412 results on '"Johnson, Sd"'
Search Results
102. 'Bleeding' flowers of Ceropegia gerrardii (Apocynaceae-Asclepiadoideae) mimic wounded insects to attract kleptoparasitic fly pollinators.
- Author
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Heiduk A, Brake I, Shuttleworth A, and Johnson SD
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- Bees, Animals, Pollination physiology, Insecta physiology, Pheromones, Flowers physiology, Diptera physiology, Apocynaceae
- Abstract
Kleptomyiophily, where flowers imitate wounded insects to attract 'kleptoparasitic' flies as pollinators, is one of the most specialized types of floral mimicry and often involves physical trapping devices. However, the diversity of pollinators and functional floral traits involved in this form of mimicry remain poorly understood. We report a novel example of kleptomyiophily in the nontrapping flowers of Ceropegia gerrardii and explore the floral traits responsible for attracting pollinators. The pollinators, reproductive biology and floral traits (including epidermal surfaces, spectral reflectance and the composition of nectariferous petal secretions and scent) were investigated. Attractive volatiles were identified using electrophysiological and behavioural experiments. Ceropegia gerrardii was predominantly pollinated by kleptoparasitic Desmometopa spp. (Milichiidae) flies. The flower corollas extrude a protein- and sugar-containing secretion, similar to the haemolymph of wounded insects, on which the flies feed. Floral scent was chemically similar to that of injured honey bees. Four out of 24 electrophysiologically active compounds, all released by injured honey bees, were identified as key players in pollinator attraction. Our results suggest that C. gerrardii flowers chemically mimic wounded honey bees to attract kleptoparasitic flies and reward them with a secretion similar to the haemolymph on which they would normally feed., (© 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation.)
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- 2023
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103. Beyond pollen:ovule ratios: Evolutionary consequences of pollinator dependence and pollination efficiency for pollen and ovule production in angiosperms.
- Author
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Harder LD and Johnson SD
- Subjects
- Phylogeny, Ovule, Bayes Theorem, Reproduction, Pollen, Flowers, Pollination, Magnoliopsida
- Abstract
Premise: The relative per-flower production of ovules and pollen varies broadly with angiosperm mating systems, with outcrossing types commonly producing more pollen grains per ovule than selfing types. The evolutionary causes of this variation are contentious, especially the relevance of pollination risk. Resolution of this debate may have been hampered by its focus on pollen:ovule (P:O) ratios rather than on the evolution of pollen and ovule numbers per se., Methods: Using published mean ovule and pollen counts, we analyzed associations with the proportion of removed pollen that reaches stigmas (pollen-transfer efficiency) and differences between pollinator-dependent and autogamous forms within and among species. Analyses involved Bayesian methods that simultaneously considered variation in pollen and ovule numbers and accounted for phylogenetic relatedness. We also assessed the utility of P:O ratios as mating-system proxies and their association with female outcrossing rates., Results: Median pollen number declined consistently with pollen-transfer efficiency among species, whereas median ovule number did not. Similarly, in both intraspecific and interspecific analyses, pollinator-dependent plants produced more pollen than autogamous plants, whereas ovule production did not differ statistically. Distributions of P:O ratios overlapped extensively for self-incompatible and self-compatible species and for different mating-system classes, and P:O ratios correlated weakly with outcrossing rate., Conclusions: Our findings demonstrate that pollinator dependence and pollination efficiency commonly influence the evolution of pollen number per flower but have more limited effects on ovule number. P:O ratios provide ambiguous, possibly misleading, information about mating systems, especially when compared among clades., (© 2023 The Authors. American Journal of Botany published by Wiley Periodicals LLC on behalf of Botanical Society of America.)
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- 2023
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104. The lady's 'slippery' orchid: functions of the floral trap and aphid mimicry in a hoverfly-pollinated Phragmipedium species in Brazil.
- Author
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Cardoso JCF, Johnson SD, Rezende UC, and Oliveira PE
- Subjects
- Animals, Female, Acclimatization, Brazil, Flowers, Pollen, Pollination, Aphids
- Abstract
Background and Aims: Trap flowers are fascinating cases of adaptation, often linked to oviposition-site mimicry systems. Some trap flowers do not imprison pollinators for a pre-determined period, but rather force them to move through a specific path, manipulating their movements in a way that culminates in pollen transfer, often as they leave through a secondary opening., Methods: We investigated the previously unknown pollination system of the lady's slipper orchid Phragmipedium vittatum and assessed the function of micro-morphological traits of its trap flowers., Key Results: Our observations revealed that P. vittatum is pollinated by females of two hoverfly species (Syrphidae). Eggs laid by flies on or near raised black spots on the flowers indicate that the orchid mimics aphids which serve as food for their aphidophagous larvae. Dark, elevated aphid-like spots appear to attract the attention of hoverflies to a slipping zone. This region has downward projecting papillate cells and mucilage secretion that promote slipperiness, causing potential pollinators to fall into the labellum. They then follow a specific upward route towards inner aphid-like spots by holding onto upward oriented hairs that aid their grip. As hoverflies are funnelled by the lateral constriction of the labellum, they pass the stigma, depositing pollen they may be carrying. Later, they squeeze under one of the articulated anthers which places pollen smears onto their upper thorax. Then, they depart through one of the narrow lateral holes by holding onto hairs projecting from the petals., Conclusions: This study confirms the system of aphid mimicry in Phragmipedium and highlights the sophisticated micro-morphological traits used by trap flowers in pollinator attraction, trapping, guidance and release, thus promoting precise pollen transfer., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2023
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105. Correlation of Adenoviral Titers with Severity of Adenoviral Conjunctivitis and Time to Viral Clearance for 21 Days.
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Morettin CE, Harthan JS, Huecker JB, Perera CD, Than T, Whiteside M, Johnson SD, Shorter E, Migneco MK, Olson CK, Alferez CS, Camp D, Hartwick ATE, and Gordon MO
- Subjects
- Humans, Pilot Projects, Povidone-Iodine, Conjunctiva, Ophthalmic Solutions, Double-Blind Method, Eye Infections, Viral diagnosis, Eye Infections, Viral drug therapy, Conjunctivitis
- Abstract
Significance: This investigation reports the correlation of conjunctival viral titers in adenoviral conjunctivitis with patient-reported symptoms and clinician-graded signs for 21 days of follow-up., Purpose: Adenoviral conjunctivitis is a highly contagious viral eye infection with significant morbidity and economic impact. This study investigates whether severity of signs and symptoms and time to viral clearance are correlated with conjunctival viral titers at baseline and during 21 days of follow-up., Methods: The Reducing Adenoviral Patient Infected Days study was a pilot study of the efficacy of a single in-office administration of ophthalmic 5% povidone-iodine. This article outlines longitudinal analyses after the primary outcome report. Of 212 participants screened, 28 participants with quantitative polymerase chain reaction-confirmed adenoviral conjunctivitis were randomized and had follow-up visits on days 1, 2, 4, 7, 14, and 21. At each visit, clinician-graded signs, participant-reported symptoms, and a conjunctival swab for quantitative polymerase chain reaction analysis were obtained. The correlation of viral titers with symptoms and signs was calculated: (1) cross-sectionally at each visit and (2) longitudinally for 21 days using a repeated-measures mixed-effects model., Results: Twenty-five of 28 participants had sufficient data for this report. Higher viral titers for 21 days were correlated with greater severity of symptoms (tearing, matting, and redness, r ≥ 0.70; P < .02) and greater severity of clinical signs (bulbar redness and serous discharge, r ≥ 0.60; P < .01). Eyes with highest baseline viral titers required longer time to viral clearance ( r = 0.59, P = .008). Signs and symptoms persisted in approximately half of the eyes even after viral clearance., Conclusions: Higher conjunctival viral titers across 21 days were strongly correlated with more severe signs and symptoms and longer time to viral clearance. Our results also indicate that symptoms and signs can persist after viral clearance., Competing Interests: Conflict of Interest Disclosure: None of the authors have reported a financial conflict of interest., (Copyright © 2023 American Academy of Optometry.)
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- 2023
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106. The Effect of COVID-19 Restrictions on Routine Activities and Online Crime.
- Author
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Johnson SD and Nikolovska M
- Abstract
Objectives: Routine activity theory suggests that levels of crime are affected by peoples' activity patterns. Here, we examine if, through their impact on people's on- and off-line activities, COVID-19 restriction affected fraud committed on- and off-line during the pandemic. Our expectation was that levels of online offending would closely follow changes to mobility and online activity-with crime increasing as restrictions were imposed (and online activity increased) and declining as they were relaxed. For doorstep fraud, which has a different opportunity structure, our expectation was that the reverse would be true., Method: COVID-19 restrictions systematically disrupted people's activity patterns, creating quasi-experimental conditions well-suited to testing the effects of "interventions" on crime. We exploit those conditions using ARIMA time series models and UK data for online shopping fraud, hacking, doorstep fraud, online sales, and mobility to test hypotheses. Doorstep fraud is modelled as a non-equivalent dependent variable, allowing us to test whether findings were selective and in line with theoretical expectations., Results: After controlling for other factors, levels of crime committed online were positively associated with monthly variation in online activities and negatively associated with monthly variation in mobility. In contrast, and as expected, monthly variation in doorstep fraud was positively associated with changes in mobility., Conclusions: We find evidence consistent with routine activity theory, suggesting that disruptions to people's daily activity patterns affect levels of crime committed both on- and off-line. The theoretical implications of the findings, and the need to develop a better evidence base about what works to reduce online crime, are discussed., Supplementary Information: The online version contains supplementary material available at 10.1007/s10940-022-09564-7., (© The Author(s) 2022.)
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- 2022
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107. Confounds and overestimations in fake review detection: Experimentally controlling for product-ownership and data-origin.
- Author
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Soldner F, Kleinberg B, and Johnson SD
- Subjects
- Humans, Research Design, Ownership
- Abstract
The popularity of online shopping is steadily increasing. At the same time, fake product reviews are published widely and have the potential to affect consumer purchasing behavior. In response, previous work has developed automated methods utilizing natural language processing approaches to detect fake product reviews. However, studies vary considerably in how well they succeed in detecting deceptive reviews, and the reasons for such differences are unclear. A contributing factor may be the multitude of strategies used to collect data, introducing potential confounds which affect detection performance. Two possible confounds are data-origin (i.e., the dataset is composed of more than one source) and product ownership (i.e., reviews written by individuals who own or do not own the reviewed product). In the present study, we investigate the effect of both confounds for fake review detection. Using an experimental design, we manipulate data-origin, product ownership, review polarity, and veracity. Supervised learning analysis suggests that review veracity (60.26-69.87%) is somewhat detectable but reviews additionally confounded with product-ownership (66.19-74.17%), or with data-origin (84.44-86.94%) are easier to classify. Review veracity is most easily classified if confounded with product-ownership and data-origin combined (87.78-88.12%). These findings are moderated by review polarity. Overall, our findings suggest that detection accuracy may have been overestimated in previous studies, provide possible explanations as to why, and indicate how future studies might be designed to provide less biased estimates of detection accuracy., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Soldner et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2022
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108. Radiographic Demonstration of Hypoxic Pulmonary Vasoconstriction during One-lung Ventilation.
- Author
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Royster RL, Johnson SD, Krupp ND, and Sullivan TP
- Subjects
- Humans, Hypoxia diagnostic imaging, Lung, Pulmonary Circulation, Vasoconstriction, One-Lung Ventilation
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- 2022
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109. Service providers' perspectives on substance use and treatment needs among human trafficking survivors.
- Author
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Koegler E, Wood CA, Johnson SD, and Bahlinger L
- Subjects
- Humans, Survivors, Referral and Consultation, Human Trafficking prevention & control, Substance-Related Disorders therapy
- Abstract
Introduction: Understanding substance use and treatment needs for survivors of human trafficking remains an underdeveloped area in the field of substance use treatment. This study assessed the nature of substance use among survivors of all types of human trafficking and identified treatment barriers and needs, as reported by human trafficking service providers in one Midwest major metropolitan area., Methods: Participants were purposively selected from agencies that served foreign-born and domestic-born survivors of human trafficking. The study interviewed fifteen key informants across 13 agencies directly serving survivors of trafficking., Results: Providers highlighted frequent use of alcohol and marijuana, as well as polysubstance use. They noted survivors' significant use of opioids, associated concerns regarding fentanyl-related deaths, and increased frequency of stimulant use. Barriers for addressing substance use problems with survivors included low self-perceptions of need, lack of available residential or inpatient treatment options, and prioritizing basic needs such as housing over substance use treatment., Conclusions: Results underscore how broader trends in substance use and overdose in a region can mirror substance use patterns and treatment needs of human trafficking survivors. Further, a need exists for broader substance use screening and low-barrier referral services to address emergent needs of survivors of trafficking., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2022 Elsevier Inc. All rights reserved.)
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- 2022
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110. Early treatment with anti-α 4 β 7 antibody facilitates increased gut macrophage maturity in SIV-infected rhesus macaques.
- Author
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Johnson SD, Knight LA, Kumar N, Olwenyi OA, Thurman M, Mehra S, Mohan M, and Byrareddy SN
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- Animals, Macaca mulatta, Antibodies therapeutic use, Macrophages, Simian Immunodeficiency Virus, Simian Acquired Immunodeficiency Syndrome, HIV Infections drug therapy
- Abstract
Despite advances in combination antiretroviral therapy (cART), people living with HIV (PLWH) continue to experience gastrointestinal dysfunction. Infusions of anti-α
4 β7 monoclonal antibodies (mAbs) have been proposed to increase virologic control during simian immunodeficiency virus (SIV) infection in macaques with mixed results. Recent evidences suggested that therapeutic efficacy of vedolizumab (a humanized anti-α4 β7 mAb), during inflammatory bowel diseases depends on microbiome composition, myeloid cell differentiation, and macrophage phenotype. We tested this hypothesis in SIV-infected, anti-α4 β7 mAb-treated macaques and provide flow cytometric and microscopic evidence that anti-α4 β7 administered to SIV-infected macaques increases the maturity of macrophage phenotypes typically lost in the small intestines during SIV disease progression. Further, this increase in mature macrophage phenotype was associated with tissue viral loads. These phenotypes were also associated with dysbiosis markers in the gut previously identified as predictors of HIV replication and immune activation in PLWH. These findings provide a novel model of anti-α4 β7 efficacy offering new avenues for targeting pathogenic mucosal immune response during HIV/SIV infection., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Johnson, Knight, Kumar, Olwenyi, Thurman, Mehra, Mohan and Byrareddy.)- Published
- 2022
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111. Bird pollination.
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Johnson SD
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- Animals, Birds, Plants, Pollination, Flowers
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Johnson gives an overview of bird pollinators and the plant species they pollinate., (Copyright © 2022 Elsevier Inc. All rights reserved.)
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- 2022
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112. Systems biology analyses reveal enhanced chronic morphine distortion of gut-brain interrelationships in simian human immunodeficiency virus infected rhesus macaques.
- Author
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Olwenyi OA, Johnson SD, Bidokhti M, Thakur V, Pandey K, Thurman M, Acharya A, Uppada S, Callen S, Giavedoni L, Ranga U, Buch SJ, and Byrareddy SN
- Abstract
Background: Commonly used opioids, such as morphine have been implicated in augmented SIV/HIV persistence within the central nervous system (CNS). However, the extent of myeloid cell polarization and viral persistence in different brain regions remains unclear. Additionally, the additive effects of morphine on SIV/HIV dysregulation of gut-brain crosstalk remain underexplored. Therefore, studies focused on understanding how drugs of abuse such as morphine affect immune dynamics, viral persistence and gut-brain interrelationships are warranted., Materials and Methods: For a total of 9 weeks, rhesus macaques were ramped-up, and twice daily injections of either morphine ( n = 4) or saline ( n = 4) administered. This was later followed with infection with SHIVAD8EO variants. At necropsy, mononuclear cells were isolated from diverse brain [frontal lobe, cerebellum, medulla, putamen, hippocampus (HIP) and subventricular zone (SVZ)] and gut [lamina propria (LP) and muscularis (MUSC) of ascending colon, duodenum, and ileum] regions. Multiparametric flow cytometry was used to were profile for myeloid cell polarity/activation and results corroborated with indirect immunofluorescence assays. Simian human immunodeficiency virus (SHIV) DNA levels were measured with aid of the digital droplet polymerase chain reaction (PCR) assay. Luminex assays were then used to evaluate soluble plasma/CSF biomarker levels. Finally, changes in the fecal microbiome were evaluated using 16S rRNA on the Illumina NovaSeq platform., Results: Flow Cytometry-based semi-supervised analysis revealed that morphine exposure led to exacerbated M1 (CD14/CD16)/M2 (CD163/CD206) polarization in activated microglia that spanned across diverse brain regions. This was accompanied by elevated SHIV DNA within the sites of neurogenesis-HIP and SVZ. HIP/SVZ CD16+ activated microglia positively correlated with SHIV DNA levels in the brain ( r = 0.548, p = 0.042). Simultaneously, morphine dependence depleted butyrate-producing bacteria, including Ruminococcus ( p = 0.05), Lachnospira ( p = 0.068) genera and Roseburia_sp_831b ( p = 0.068). Finally, morphine also altered the regulation of CNS inflammation by reducing the levels of IL1 Receptor antagonist (IL1Ra)., Conclusion: These findings are suggestive that morphine promotes CNS inflammation by altering receptor modulation, increasing myeloid brain activation, distorting gut-brain crosstalk, and causing selective enhancement of SHIV persistence in sites of neurogenesis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Olwenyi, Johnson, Bidokhti, Thakur, Pandey, Thurman, Acharya, Uppada, Callen, Giavedoni, Ranga, Buch and Byrareddy.)
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- 2022
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113. Ion Mobility and Fourier Transform Ion Cyclotron Resonance Collision Cross Section Techniques Yield Long-Range and Hard-Sphere Results, Respectively.
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Heravi T, Arslanian AJ, Johnson SD, and Dearden DV
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- Fourier Analysis, Ions, Cyclotrons, Metals, Alkali
- Abstract
We determined collision cross section (CCS) values for singly and doubly charged cucurbit[ n ]uril ( n = 5-7), decamethylcucurbit[5]uril, and cyclohexanocucurbit[5]uril complexes of alkali metal cations (Li
+ -Cs+ ). These hosts are relatively rigid. CCS values calculated using the projection approximation (PA) for computationally modeled structures of a given host are nearly identical for +1 and +2 complexes, with weak metal ion dependence, whereas trajectory method (TM) calculations of CCS for the same structures consistently yield values 7-10% larger for the +2 complexes than for the corresponding +1 complexes and little metal ion dependence. Experimentally, we measured relative CCS values in SF6 for pairs of +1 and +2 complexes of the cucurbituril hosts using the cross-sectional areas by Fourier transform ion cyclotron resonance ("CRAFTI") method. At center-of-mass collision energies <∼30 eV, CRAFTI CCS values are sensitive to the relative binding energies in the +1 and +2 complexes, but at collision energies >∼40 eV (sufficient that ion decoherence occurs on essentially every collision) that dependence is not evident. Consistent with the PA calculations, these experiments found that the +2 complex ions have CCS values ranging between 94 and 105% of those of their +1 counterparts (increasing with metal ion size). In contrast, but consistent with the TM CCS calculations, ion mobility measurements of the same complexes at close to thermal energies in much less polarizable N2 find the CCS of +2 complexes to be in all cases 9-12% larger than those of the corresponding +1 complexes, with little metal ion dependence.- Published
- 2022
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114. Intraoperative Transesophageal Echocardiographic Detection of a Gerbode Defect in a Patient Referred for Aortic Valve Endocarditis: A Case Report.
- Author
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Fernando RJ, Johnson SD, and Richardson K
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- Aortic Valve diagnostic imaging, Aortic Valve surgery, Echocardiography, Transesophageal, Humans, Aortic Valve Insufficiency diagnostic imaging, Aortic Valve Insufficiency surgery, Endocarditis complications, Endocarditis diagnostic imaging, Endocarditis surgery, Endocarditis, Bacterial complications, Endocarditis, Bacterial diagnostic imaging, Endocarditis, Bacterial surgery, Heart Septal Defects, Ventricular surgery, Hypertension, Pulmonary
- Abstract
This clinical challenge discusses a case in which a patient was referred for aortic valve repair or replacement due to severe aortic regurgitation from infective endocarditis. In addition to discovering a previously unknown tricuspid valve vegetation, the intraoperative echocardiographic evaluation was instrumental in revealing an undiagnosed Gerbode defect. The flow through this Gerbode defect was previously mistaken for tricuspid regurgitation, and the patient was misdiagnosed as exhibiting severe pulmonary hypertension. This case highlights the importance of reviewing preoperative echocardiographic imaging, as well as diligence in completing a thorough intraoperative transesophageal echocardiographic exam prior to cardiopulmonary bypass. In addition, while flow typically occurs in Gerbode defects during systole, this case demonstrates that flow can also occur during diastole, which was most likely due to the severe aortic regurgitation. Fortunately, the patient was able to undergo successful treatment for the unexpected sequalae of the infective endocarditis, including repair of the Gerbode defect, tricuspid valve repair, and aortic valve and root replacement. Importantly, the incorrect diagnosis of severe pulmonary hypertension was removed.
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- 2022
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115. Diagnostic accuracy of clinical signs, symptoms and point-of-care testing for early adenoviral conjunctivitis.
- Author
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Shorter ES, Whiteside MM, Harthan JS, Morettin CE, Perera CD, Johnson SD, Migneco MK, Huecker JB, Hartwick ATE, Than TP, and Gordon MO
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- Adult, Humans, Point-of-Care Testing, Polymerase Chain Reaction methods, Adenovirus Infections, Human diagnosis, Adenovirus Infections, Human drug therapy, Conjunctivitis diagnosis, Conjunctivitis, Viral diagnosis, Conjunctivitis, Viral drug therapy
- Abstract
Clinical Relevance: This study identifies key signs and symptoms of acute conjunctivitis, that when combined with a point-of-care test, can improve clinician accuracy of diagnosing adenoviral conjunctivitis., Background: Adenoviral conjunctivitis is a common ocular infection with the potential for high economic impact due to widespread outbreaks and subsequent furloughs from work and school. In this report, we describe clinical signs and participant-reported symptoms that most accurately identify polymerase chain reaction (PCR)-confirmed adenoviral conjunctivitis., Methods: Adults with 'red eye' symptoms of four days or less were enrolled. Participants rated 10 ocular symptoms from 0 (not bothersome) to 10 (very bothersome), and indicated the presence or absence of systemic flu-like symptoms. Clinicians determined the presence or absence of swollen lymph nodes and rated the severity of eight ocular signs using a 5-point scale. An immunoassay targeting adenovirus antigen was utilised for the point-of-care test, and conjunctival swab samples were obtained for subsequent adenovirus detection by PCR analyses. Univariate and multivariate logistic regression models were used to identify symptoms and signs associated with PCR-confirmed adenoviral conjunctivitis. The diagnostic accuracy of these clinical findings, and the potential benefit of incorporating point-of-care test results, was assessed by calculating areas under the receiver operating characteristic curves (AUC)., Results: Clinician-rated bulbar conjunctival redness, participant-rated eyelid swelling and overall ocular discomfort had the best predictive value in the multivariate logistic regression model with an AUC of 0.83. The addition of the point-of-care test results to these three clinical sign/symptom scores improved diagnostic accuracy, increasing the AUC to 0.94., Conclusions: Conjunctival redness severity and participant-reported eyelid swelling and overall discomfort, along with adenoviral point-of-care test results, were highly predictive in identifying individuals with PCR-confirmed adenoviral conjunctivitis. Improved diagnostic accuracy by clinicians at the initial presenting visit could prevent unnecessary work furloughs and facilitate earlier treatment decisions.
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- 2022
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116. Household occupancy and burglary: A case study using COVID-19 restrictions.
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Frith MJ, Bowers KJ, and Johnson SD
- Abstract
Introduction: In response to COVID-19, governments imposed various restrictions on movement and activities. According to the routine activity perspective, these should alter where crime occurs. For burglary, greater household occupancy should increase guardianship against residential burglaries, particularly during the day considering factors such as working from home. Conversely, there should be less eyes on the street to protect against non-residential burglaries., Methods: In this paper, we test these expectations using a spatio-temporal model with crime and Google Community Mobility data., Results: As expected, burglary declined during the pandemic and restrictions. Different types of burglary were, however, affected differently but largely consistent with theoretical expectation. Residential and attempted residential burglaries both decreased significantly. This was particularly the case during the day for completed residential burglaries. Moreover, while changes were coincident with the timing and relaxation of restrictions, they were better explained by fluctuations in household occupancy. However, while there were significant decreases in non-residential and attempted non-residential burglary, these did not appear to be related to changes to activity patterns, but rather the lockdown phase., Conclusions: From a theoretical perspective, the results generally provide further support for routine activity perspective. From a practical perspective, they suggest considerations for anticipating future burglary trends., Competing Interests: None., (© 2022 Published by Elsevier Ltd.)
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- 2022
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117. Single oral or intravenous administration of voriconazole achieved recommended therapeutic minimum inhibitory concentrations against Aspergillus in the common raven (Corvus corax).
- Author
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Johnson SD, Buchweitz JP, and Lehner AF
- Subjects
- Administration, Intravenous veterinary, Administration, Oral, Animals, Antifungal Agents, Area Under Curve, Aspergillus, Microbial Sensitivity Tests veterinary, Pyrimidines, Triazoles, Voriconazole, Crows
- Abstract
Objective: To determine the pharmacokinetics of voriconazole after single IV or orally administered boluses in common ravens (Corvus corax)., Animals: 8 healthy common ravens., Procedures: Voriconazole (5 mg/mL, 10 mg/kg IV) was administered to 8 birds, and then plasma voriconazole concentrations were measured at various time points by high-pressure liquid chromatography with mass spectrometry. Starting 6 months later in a randomized 3-treatment 3-period regimen, birds received a single oral dose of voriconazole suspension (10 mg/mL; 6, 12, and 24 mg/kg PO). The study period was May 2015 to March 2016., Results: Voriconazole (10 mg/kg IV) achieved an initial plasma concentration of 6.31 µg/mL when measured over 21 hours. After oral administration of voriconazole at 6, 12, and 24 mg/kg, the relative bioavailability was 67.5%, 209%, and 183%, respectively. For the 6-mg/kg dose, the maximum plasma concentration was reached at 30 minutes after administration and remained in the therapeutic range of 0.5 to 1 µg/mL for approximately 15 hours. The 12- and 24-mg/kg doses resulted in concentrations in a potentially toxic range., Clinical Relevance: Voriconazole was well tolerated. All 4 doses resulted in plasma concentrations of voriconazole > 0.5 µg/mL, which is the minimum inhibitory concentration recommended for pathogenic species of Aspergillus fungi known to affect birds. A single dose of voriconazole administered as 10 mg/kg IV or 6 mg/kg PO resulted in recommended target plasma concentrations. Administration of voriconazole 6 mg/kg PO 2 to 3 times daily may be adequate for treatment without exceeding the toxic range.
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- 2022
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118. Biomechanics of nectar feeding explain flower orientation in plants pollinated by long-proboscid flies.
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McCarren S, Midgley JJ, and Johnson SD
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- Animals, Biomechanical Phenomena, Flowers, Plant Nectar, Plants, Pollination, Butterflies, Diptera
- Abstract
The function of flower orientation is much debated, with adaptation to pollinator mouthparts being a particularly compelling explanation, but also one that has lacked empirical support from broad-scale comparative studies. The two families of long-proboscid fly pollinators show similar hovering behaviour while feeding on nectar but differ in the biomechanics of their proboscides which can be up to 80 mm in length: Tabanidae have a fixed forward-pointing proboscis while Nemestrinidae can swivel their proboscis downwards. We predicted that this difference has implications for the evolution of flower orientation. We established the flower angles of 156 South African plant species specialised for pollination by long-proboscid flies. Using a phylogenetically corrected analysis, we found that flowers pollinated by Tabanidae tend to be horizontally orientated, while those pollinated by Nemestrinidae tend to be more variable in orientation and more often vertically orientated. These results confirm the importance of pollinator biomechanics for the evolution of floral traits and highlight a potential mechanism of reproductive isolation between sympatric plant species pollinated by different long-proboscid fly families., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2022
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119. A generalized bird pollination system in Schotia brachypetala (Fabaceae).
- Author
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Kiepiel I, Brown M, and Johnson SD
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- Animals, Flowers, Plant Breeding, Plant Nectar, Pollination, Trees, Fabaceae, Passeriformes
- Abstract
Bird pollination systems are diverse, ranging from narrow-tubed flowers pollinated by specialist nectarivores such as hummingbirds and sunbirds, to relatively open flowers pollinated by opportunistic (i.e. generalist) nectarivores. The role of opportunistic avian nectarivores as pollinators has historically been under-appreciated. A key aspect to understanding the importance of opportunistic birds as pollinators is to investigate how efficiently they transfer pollen among flowers. Here, we document the pollination and breeding systems of Schotia brachypetala, a southern African tree known as the 'weeping boer-bean' on account of its prolific production of dilute hexose-dominated nectar. The cup-shaped flowers of this tree attract a large number of bird species, including both opportunistic and specialist nectarivores. We identified floral visitors using observations and camera traps and quantified the floral traits responsible for animal attraction. We documented the breeding system, used selective pollinator exclusion to test the contribution of birds to fecundity, and performed supplemental pollination to test for pollen limitation. Single-visit pollen deposition trials were undertaken to determine the efficacy of bird pollinators. Controlled hand-pollination experiments showed that S. brachypetala is genetically self-incompatible and therefore dependent on pollinators for seed production. Supplemental hand-pollination experiments showed that natural fecundity is limited by either the amount and/or the quality of pollen on stigmas. Flowers from which birds but not insects were experimentally excluded set fewer seeds than open control flowers. Opportunistic birds deposited more pollen per visit than did specialist sunbirds. We conclude that S. brachypetala has a generalized bird pollination system that mainly involves opportunistic nectarivores., (© 2022 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.)
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- 2022
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120. Why honeybees are poor pollinators of a mass-flowering plant: Experimental support for the low pollen quality hypothesis.
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Diller C, Castañeda-Zárate M, and Johnson SD
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- Animals, Flowers, Pollen, Seeds, Bees, Magnoliopsida, Pollination
- Abstract
Premise: Honeybees dominate the flower-visitor assemblages of many plant species, yet their efficiency in terms of the quality of pollen delivered to stigmas is largely unknown. We investigated why honeybees are poor pollinators of Aloe ferox, a self-incompatible succulent treelet with large numbers of flowers. Honeybees are very frequent visitors to flowers of this species, yet contribute very little to seed production., Methods: We assessed pollen loads on honeybees, studied their visitation behavior, selectively excluded birds from plants to determine direct effects of bees on pollen deposition, seed set, and ovule abortion, and used a novel "split-pollinator" method to test whether honeybees deposit mainly low-quality self pollen. For the latter, we captured honeybees, and with their existing pollen loads, used them to either pollinate virgin flowers on the plant on which they were caught or to pollinate virgin flowers on different plants., Results: Honeybees cumulatively deposit as much pollen on stigmas as do birds, but our experiments showed that the pollen deposited by honeybees is mostly low-quality self pollen that leads to substantial ovule discounting and depressed seed set., Conclusions: Lack of movement among A. ferox plants during individual honeybee foraging bouts is the most likely explanation for their deposition of low-quality self pollen on stigmas. The "split-pollinator" method is a simple and cost-effective technique to test the quality of pollination., (© 2022 The Authors. American Journal of Botany published by Wiley Periodicals LLC on behalf of Botanical Society of America.)
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- 2022
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121. Rodent responses to volatile compounds provide insights into the function of floral scent in mammal-pollinated plants.
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Johnson SD and Govender K
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- Animals, Esters, Ketones, Mammals, Odorants, Rodentia physiology
- Abstract
Flowers pollinated by mammals have evolved in many plant families. Several scent compounds that attract bats to flowers have been identified, but the chemical ecology of pollination mutualisms between plants and ground-dwelling mammals is poorly understood. Rodents are key pollinators in South Africa and rely heavily on olfaction to locate food. Our aim was to identify compounds that may function to attract rodents to flowers. Eighteen volatile compounds, including 14 that are prominent in the scent of rodent-pollinated flowers, were used in choice experiments involving wild-caught individuals of four native rodent species. Rodents were generally attracted to oxygenated aliphatic compounds, specifically ketones and esters, but not to some aromatic compounds common in floral scents of insect-pollinated species, nor to a sulfide compound that is attractive to bats. Associative conditioning using sugar solution as a reward had only weak effects on the attractiveness of compounds to rodents. The attractive effect of some compounds disappeared when they were blended with compounds that did not attract rodents. We conclude that aliphatic ketones and esters are likely to play a key role in attracting rodents to flowers. Deployment of these compounds may allow plants to exploit rodent sensory bias that evolved in other contexts such as intra-specific communication and searching for seeds. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.
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- 2022
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122. HIV-associated dysbiosis and immune recovery during antiretroviral therapy.
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Johnson SD and Byrareddy SN
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The microbiomes of people living with HIV (PLWH) are significantly dysregulated with a loss of bacteria diversity and shifts in composition, including increases in pathogenic and decreases in beneficial species. Because of the microbiome's role in modulating health, the effect of this dysbiosis on immune response in PLWH has been a significant concern, mainly because these shifts can persist even after viral suppression during combination antiretroviral therapy (cART). However, due to limitations on sample availability, few studies have been able to provide insights into these microbiome-immune interactions. Recently, Olivas-Martínez, et al. characterized ileum and caecum mucosa-associated microbiomes of PLWH based on their level of peripheral CD4+ T-cell reconstitution following long-term cART. Their analysis revealed distinct microbiome signatures predictive of recovery. Additionally, differences in markers of gut inflammation and damage between response groups were described, further implicating mucosal disruptions with immune reconstitution. These new data demonstrate an interdependence of microbiome and therapy response, and additional studies were urgently required to fully elucidate this crosstalk and microbiome dynamics from before/after infection and finally, long-term viral suppression with cART., Competing Interests: Conflict of Interest The authors declare no conflict of interest.
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- 2022
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123. Chronic Opioid Administration is Associated with Prevotella-dominated Dysbiosis in SIVmac251 Infected, cART-treated Macaques.
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Johnson SD, Fox HS, Buch S, and Byrareddy SN
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- Humans, Animals, Analgesics, Opioid toxicity, RNA, Ribosomal, 16S, Macaca mulatta, Opioid-Related Disorders, HIV Infections
- Abstract
People living with the human immunodeficiency virus (HIV) have an elevated risk of opioid misuse due to both prescriptions for HIV-associated chronic pain and because injection drug use remains a primary mode of HIV transmission. HIV pathogenesis is characterized by chronic immune activation and microbial dysbiosis, and translocation across the gut barrier exacerbating inflammation. Despite the high rate of co-occurrence, little is known about the microbiome during chronic opioid use in the context of HIV and combination antiretroviral therapy (cART). We recently demonstrated the reduction of the CD4 + T-cell reservoir in lymphoid tissues but increased in microglia/macrophage reservoirs in CNS by using morphine-treated, simian immunodeficiency virus (SIV)-infected rhesus macaques with viremia suppressed by cART. To understand whether morphine may perturb the gut-brain axis, fecal samples were collected at necropsy, DNA isolated, and 16S rRNA sequenced and changes of the microbiome analyzed. We found that morphine treatment led to dysbiosis, primarily characterized by expansion of Bacteroidetes, particularly Prevotellaceae, at the expense of Firmicutes and other members of healthy microbial communities resulting in a lower α-diversity. Of the many genera in Prevotellaceae, the differences between the saline and morphine group were primarily due to a higher relative abundance of Prevotella_9, the taxa most similar to Prevotella copri, an inflammatory pathobiont in the human microbiome. These findings reinforce previous research showing that opioid abuse is associated with dysbiosis, therefore, warranting additional future research to elucidate the complex interaction between the host and opioid abuse during HIV and SIV infection., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2022
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124. Progression of muscle loss and fat accumulation in a rabbit model of rotator cuff tear.
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Vargas-Vila MA, Gibbons MC, Wu IT, Esparza MC, Kato K, Johnson SD, Masuda K, and Ward SR
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- Adipose Tissue pathology, Animals, Female, Fibrosis, Muscular Atrophy pathology, Rabbits, Rotator Cuff pathology, Rotator Cuff Injuries pathology
- Abstract
Rotator cuff (RC) tears present a treatment challenge due to muscle atrophy and degeneration, fatty infiltration, and fibrosis. The purpose of this study was to generate a high time-resolution model of RC tear in rabbits and to characterize the progression of architectural and histological changes. Thirty-five female New Zealand White rabbits (age: 6 months) underwent left supraspinatus tenotomy. Five rabbits were used to evaluate immediate muscle architectural changes. The remaining 30 rabbits underwent right shoulder sham surgery and sacrifice at 1, 2, 4, 8, or 16 weeks. Histology was used to quantify muscle fiber cross-sectional area (CSA), muscle degeneration and regeneration, and fat localized to inter- versus intrafascicular regions. Muscle fiber CSA decreased by 26.5% compared to sham at 16 weeks (effect of treatment, p < 0.0001). Muscle degeneration increased after tenotomy (effect of treatment, p = 0.0006) without any change in regeneration. Collagen and fat content increased by 4 weeks and persisted through 16 weeks. Interfascicular fat was increased at all time points, but intrafascicular fat was increased only at 1, 4, and 16 weeks posttenotomy. Intrafascicular fat adjacent to degenerating muscle fibers increased as well (effect of treatment, p < 0.0001; effect of time, p = 0.0102). Statement of clinical relevance: Rabbit supraspinatus tenotomy recapitulates key features of the pathophysiology of human RC tears, including muscle atrophy and degeneration, lack of regeneration, fat accumulation, and fibrosis., (© 2021 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)
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- 2022
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125. Erratum to Efficacy of a Single Administration of 5% Povidone-Iodine in the Treatment of Adenoviral Conjunctivitis. Am J Ophthalmol 2021;231:28-38.
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Than T, Morettin CE, Harthan JS, Hartwick ATE, Huecker JB, Johnson SD, Migneco MK, Shorter E, Whiteside M, Margolis MS, Olson CK, Alferez CS, Zyl TV, Rodic-Polic B, Storch GA, and Gordon MO
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- 2022
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126. Cryptocurrencies and future financial crime.
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Trozze A, Kamps J, Akartuna EA, Hetzel FJ, Kleinberg B, Davies T, and Johnson SD
- Abstract
Background: Cryptocurrency fraud has become a growing global concern, with various governments reporting an increase in the frequency of and losses from cryptocurrency scams. Despite increasing fraudulent activity involving cryptocurrencies, research on the potential of cryptocurrencies for fraud has not been examined in a systematic study. This review examines the current state of knowledge about what kinds of cryptocurrency fraud currently exist, or are expected to exist in the future, and provides comprehensive definitions of the frauds identified., Methods: The study involved a scoping review of academic research and grey literature on cryptocurrency fraud and a 1.5-day expert consensus exercise. The review followed the PRISMA-ScR protocol, with eligibility criteria based on language, publication type, relevance to cryptocurrency fraud, and evidence provided. Researchers screened 391 academic records, 106 of which went on to the eligibility phase, and 63 of which were ultimately analysed. We screened 394 grey literature sources, 128 of which passed on to the eligibility phase, and 53 of which were included in our review. The expert consensus exercise was attended by high-profile participants from the private sector, government, and academia. It involved problem planning and analysis activities and discussion about the future of cryptocurrency crime., Results: The academic literature identified 29 different types of cryptocurrency fraud; the grey literature discussed 32 types, 14 of which were not identified in the academic literature (i.e., 47 unique types in total). Ponzi schemes and (synonymous) high yield investment programmes were most discussed across all literature. Participants in the expert consensus exercise ranked pump-and-dump schemes and ransomware as the most profitable and feasible threats, though pump-and-dumps were, notably, perceived as the least harmful type of fraud., Conclusions: The findings of this scoping review suggest cryptocurrency fraud research is rapidly developing in volume and breadth, though we remain at an early stage of thinking about future problems and scenarios involving cryptocurrencies. The findings of this work emphasise the need for better collaboration across sectors and consensus on definitions surrounding cryptocurrency fraud to address the problems identified., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2021.)
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- 2022
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127. Antibiotic-functionalized gold nanoparticles for the detection of active β-lactamases.
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Miller LM, Simmons MD, Silver CD, Krauss TF, Thomas GH, Johnson SD, and Duhme-Klair AK
- Abstract
Antimicrobial resistance (AMR) continues to threaten the effective treatment and prevention of bacterial infections. The spread of resistant infections is accelerated by the lack of fast and cost-effective tests for the detection of AMR at the point-of-care. We aimed to address this challenge by developing a diagnostic tool to detect one of the major forms of AMR, the β-lactamase enzymes. Antibiotic-functionalized gold nanoparticles (AuNPs) have been successfully developed for the detection of β-lactamases in challenging biological media, namely undiluted urine. Furthermore, these tools are compatible with samples containing a urine sample preservative (boric acid) or hematuria (blood). The functionalized AuNPs interact with the active β-lactamases, resulting in the hydrolysis of the surface-bound antibiotics, which then inhibits binding of the AuNPs to a capture protein (a penicillin-binding protein) to indicate the presence of active β-lactamases. We successfully integrated the antibiotic-functionalized AuNPs into a new lateral flow assay (LFA), which can be used to detect active β-lactamases down to the detection limit of 11 nM. While we demonstrate the use of antibiotic-functionalized AuNPs in an LFA format to provide a novel method of detecting active β-lactamases, these functionalized AuNPs are amenable to a range of alternative diagnostic technologies and could lead to vital point-of-care diagnostics for the early detection of multi-drug resistant infections., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper., (This journal is © The Royal Society of Chemistry.)
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- 2021
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128. Efficacy of a Single Administration of 5% Povidone-Iodine in the Treatment of Adenoviral Conjunctivitis.
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Than T, Morettin CE, Harthan JS, Hartwick ATE, Huecker JB, Johnson SD, Migneco MK, Shorter E, Whiteside M, Olson CK, Alferez CS, van Zyl T, Rodic-Polic B, Storch GA, and Gordon MO
- Subjects
- Double-Blind Method, Glucocorticoids, Humans, Lubricant Eye Drops, Ophthalmic Solutions, Treatment Outcome, Conjunctivitis, Povidone-Iodine
- Abstract
Purpose: To evaluate the safety and efficacy of a single, in-office administration of 5% povidone-iodine (PVP-I) compared to artificial tears (AT) for adenoviral conjunctivitis (Ad-Cs)., Design: Double-masked pilot randomized trial., Methods: Patients presenting with presumed adenoviral conjunctivitis were screened at 9 U.S. clinics., Inclusion Criteria: ≥18 years of age, symptoms ≤4 days, and a positive AdenoPlus test., Exclusion Criteria: thyroid disease, iodine allergy, recent ocular surgery, and ocular findings inconsistent with early-stage Ad-Cs. Randomization was to a single administration of 5% PVP-I or AT in 1 eye and examinations on days 1-2, 4, 7, 14, and 21 with conjunctival swabs taken at each visit for quantitative polymerase chain reaction. Primary outcome was percent reduction from peak viral load. Secondary outcomes were improvement in clinical signs and symptoms., Results: Of 56 patients randomized, 28 had detectable viral titers at baseline. Day 4 posttreatment, viral titers in the 5% PVP-I and AT groups were 2.5% ± 2.7% and 14.4% ± 10.5% of peak, respectively (P = .020). Severity of participant-reported tearing, lid swelling, and redness as well as clinician-graded mucoid discharge, bulbar redness, and bulbar edema were lower in the 5% PVP-I group than AT group on day 4 (P < .05). After day 4, viral titers and severity of signs and symptoms decreased markedly in both groups and no differences between groups were detected., Conclusions: Pilot data suggest a single, in-office administration of 5% PVP-I could reduce viral load and hasten improvement of clinical signs and symptoms in patients with Ad-Cs., (Copyright © 2021 Elsevier Inc. All rights reserved.)
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- 2021
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129. Mental Health Issues During and After COVID-19 Vaccine Era.
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Pandey K, Thurman M, Johnson SD, Acharya A, Johnston M, Klug EA, Olwenyi OA, Rajaiah R, and Byrareddy SN
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- COVID-19 Vaccines administration & dosage, Communicable Disease Control, Humans, Longitudinal Studies, Mental Health trends, Pandemics prevention & control, Public Health, SARS-CoV-2 pathogenicity, Vaccination trends, Vaccination Refusal trends, Vaccines, COVID-19 psychology, Vaccination psychology, Vaccination Refusal psychology
- Abstract
The COVID-19 pandemic has persisted for more than a year, and post-COVID-19 sequelae of neurological complications, including direct and indirect effects on the central nervous system (CNS), have been recognized. There is a plethora of evidence for neurological, cognitive, and emotional deficits in COVID-19 patients. Acute neurological symptoms like neuroinflammation, cognitive impairment, loss of smell, and brain stroke are common direct effects among SARS-CoV-2 infected individuals. Work-associated stress, lockdowns, social distancing, and quarantine in response to contain SARS-CoV-2 have also affected the mental health of large populations, regardless of age. Public health emergencies have affected individuals and communities, resulting in emotional reactions and unhealthy behaviors. Although vaccines have been widely distributed and administered among large populations, vaccine hesitancy still exists and may be due to apprehension about vaccine efficacy, preliminary trials, and associated side effects. This review highlights the impact of COVID-19 on the CNS by outlining direct and indirect effects and factors contributing to the decline in people's mental health throughout the COVID-19 pandemic both during and after vaccine administration. Furthermore, we also discuss reasons for vaccine hesitancy and why some groups of people are deprived of vaccines. Finally, we touched upon the social determinants of mental health and their impact on disadvantaged populations during times of crisis which may help policymakers set up some action plans to mitigate the COVID-19 mental health turmoil during this ongoing pandemic., (Copyright © 2021 Elsevier Inc. All rights reserved.)
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- 2021
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130. Diminished Peripheral CD29hi Cytotoxic CD4+ T Cells Are Associated With Deleterious Effects During SIV Infection.
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Olwenyi OA, Johnson SD, Pandey K, Thurman M, Acharya A, Buch SJ, Fox HS, Podany AT, Fletcher CV, and Byrareddy SN
- Subjects
- Animals, Anti-Retroviral Agents pharmacology, Cells, Cultured, Cytokines metabolism, Disease Models, Animal, Host-Pathogen Interactions, Macaca mulatta, Morphine pharmacology, Phenotype, Simian Acquired Immunodeficiency Syndrome drug therapy, Simian Acquired Immunodeficiency Syndrome metabolism, Simian Acquired Immunodeficiency Syndrome virology, Simian Immunodeficiency Virus drug effects, Simian Immunodeficiency Virus growth & development, T-Lymphocytes, Cytotoxic drug effects, T-Lymphocytes, Cytotoxic metabolism, T-Lymphocytes, Cytotoxic virology, Viral Load, Virus Replication, Cytotoxicity, Immunologic, Integrin beta1 metabolism, Simian Acquired Immunodeficiency Syndrome immunology, Simian Immunodeficiency Virus immunology, T-Lymphocytes, Cytotoxic immunology
- Abstract
Cytotoxic CD4+ T cells (CD4+ CTLs) limit HIV pathogenesis, as evidenced in elite controllers (a subset of individuals who suppress the virus without the need for therapy). CD4+ CTLs have also been shown to kill HIV-infected macrophages. However, little is known about their contribution towards HIV persistence, how they are affected following exposure to immune modulators like morphine, and what factors maintain their frequencies and function. Further, the lack of robust markers to identify CD4+ CTLs in various animal models limits understanding of their role in HIV pathogenesis. We utilized various PBMC samples obtained from SIV infected and cART treated rhesus macaques exposed to morphine or saline and subjected to flow cytometry evaluations. Thereafter, we compared and correlated the expression of CD4+ CTL-specific markers to viral load and viral reservoir estimations in total CD4+ T cells. We found that CD29 could be reliably used as a marker to identify CD4+ CTLs in rhesus macaques since CD29hi CD4+ T cells secrete higher cytotoxic and proinflammatory cytokines following PMA/ionomycin or gag stimulation. In addition, this immune cell subset was depleted during untreated SIV infection. Strikingly, we also observed that early initiation of cART reconstitutes depleted CD29hi CD4+ T cells and restores their function. Furthermore, we noted that morphine exposure reduced the secretion of proinflammatory cytokines/cytotoxic molecules in CD29hi CD4+ T cells. Lastly, increased functionality of CD29hi CD4+ T cells as depicted by elevated levels of either IL-21 or granzyme B hi T Bet+ gag specific responses were linked to limiting the size of the replication-competent reservoir during cART treatment. Collectively, our data suggest that CD4+ CTLs are crucial in limiting SIV pathogenesis and persistence., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Olwenyi, Johnson, Pandey, Thurman, Acharya, Buch, Fox, Podany, Fletcher and Byrareddy.)
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- 2021
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131. Author Correction: A global-scale expert assessment of drivers and risks associated with pollinator decline.
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Dicks LV, Breeze TD, Ngo HT, Senapathi D, An J, Aizen MA, Basu P, Buchori D, Galetto L, Garibaldi LA, Gemmill-Herren B, Howlett BG, Imperatriz-Fonseca VL, Johnson SD, Kovács-Hostyánszki A, Kwon YJ, Lattorff HMG, Lungharwo T, Seymour CL, Vanbergen AJ, and Potts SG
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- 2021
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132. A global-scale expert assessment of drivers and risks associated with pollinator decline.
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Dicks LV, Breeze TD, Ngo HT, Senapathi D, An J, Aizen MA, Basu P, Buchori D, Galetto L, Garibaldi LA, Gemmill-Herren B, Howlett BG, Imperatriz-Fonseca VL, Johnson SD, Kovács-Hostyánszki A, Kwon YJ, Lattorff HMG, Lungharwo T, Seymour CL, Vanbergen AJ, and Potts SG
- Subjects
- Crops, Agricultural, Europe, Humans, North America, Pesticides, Pollination
- Abstract
Pollinator decline has attracted global attention and substantial efforts are underway to respond through national pollinator strategies and action plans. These policy responses require clarity on what is driving pollinator decline and what risks it generates for society in different parts of the world. Using a formal expert elicitation process, we evaluated the relative regional and global importance of eight drivers of pollinator decline and ten consequent risks to human well-being. Our results indicate that global policy responses should focus on reducing pressure from changes in land cover and configuration, land management and pesticides, as these were considered very important drivers in most regions. We quantify how the importance of drivers and risks from pollinator decline, differ among regions. For example, losing access to managed pollinators was considered a serious risk only for people in North America, whereas yield instability in pollinator-dependent crops was classed as a serious or high risk in four regions but only a moderate risk in Europe and North America. Overall, perceived risks were substantially higher in the Global South. Despite extensive research on pollinator decline, our analysis reveals considerable scientific uncertainty about what this means for human society., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)
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- 2021
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133. Florivory can facilitate rain-assisted autogamy in a deceptive tropical orchid.
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Cardoso JCF, Johnson SD, Maciel AA, and Oliveira PE
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- Animals, Bees, Flowers, Pollen, Rain, Orchidaceae, Pollination
- Abstract
Florivores and rainfall generally have negative impacts on plant fecundity. However, in some cases, they can mediate fruit set. Some plants face severe pollen-limited fecundity and any additional fruit set, even if from self-pollination, can be advantageous. This is the case in some tropical deceptive orchids, such as the threatened Cyrtopodium hatschbachii. Here we test the hypothesis that florivory of the anther cap would facilitate rain-assisted autogamy in this species. In the field, we followed flowers in which the anther cap was removed by the orthopteran Stenopola sp. and found cases where pollinia self-deposited after rainfall and in one case this resulted in swelling of the column typical of fruit development. This event comprised 33% of all fruit set in the population in 2019. We then experimentally varied anther cap removal and rainfall in a factorial design and found increased fruit set in the group with cap removal (simulated florivory) followed by rain. The water absorption by pollinia makes them heavier, causing the stipe to bend. The droplet of water on the stigma then shrinks and pulls the pollinia back onto the stigma, causing self-pollination. Seeds from self-pollination have considerable viability and may allow population persistence, given that bee-mediated cross-pollination is uncertain and even absent in some years. Our study provides a unique example of how two unrelated factors (i.e., florivory and rain) that are detrimental alone may together promote fruit set., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2021
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134. Therapeutic implications of SARS-CoV-2 dysregulation of the gut-brain-lung axis.
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Johnson SD, Olwenyi OA, Bhyravbhatla N, Thurman M, Pandey K, Klug EA, Johnston M, Dyavar SR, Acharya A, Podany AT, Fletcher CV, Mohan M, Singh K, and Byrareddy SN
- Subjects
- Brain, Humans, Lung, Pandemics, Prospective Studies, COVID-19, SARS-CoV-2
- Abstract
The emergence and rapid spread of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused over 180 million confirmed cases resulting in over 4 million deaths worldwide with no clear end in sight for the coronavirus disease 19 (COVID-19) pandemic. Most SARS-CoV-2 exposed individuals experience mild to moderate symptoms, including fever, cough, fatigue, and loss of smell and taste. However, many individuals develop pneumonia, acute respiratory distress syndrome, septic shock, and multiorgan dysfunction. In addition to these primarily respiratory symptoms, SARS-CoV-2 can also infiltrate the central nervous system, which may damage the blood-brain barrier and the neuron's synapses. Resultant inflammation and neurodegeneration in the brain stem can further prevent efferent signaling to cranial nerves, leading to the loss of anti-inflammatory signaling and normal respiratory and gastrointestinal functions. Additionally, SARS-CoV-2 can infect enterocytes resulting in gut damage followed by microbial dysbiosis and translocation of bacteria and their byproducts across the damaged epithelial barrier. As a result, this exacerbates pro-inflammatory responses both locally and systemically, resulting in impaired clinical outcomes. Recent evidence has highlighted the complex interactions that mutually modulate respiratory, neurological, and gastrointestinal function. In this review, we discuss the ways SARS-CoV-2 potentially disrupts the gut-brain-lung axis. We further highlight targeting specific responses to SARS-CoV-2 for the development of novel, urgently needed therapeutic interventions. Finally, we propose a prospective related to the individuals from Low- and Middle-Income countries. Here, the underlying propensity for heightened gut damage/microbial translocation is likely to result in worse clinical outcomes during this COVID-19 pandemic., Competing Interests: Conflict-of-interest statement: Authors declare no conflict of interests for this article., (©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.)
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- 2021
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135. Predictive Accuracy and Densitometric Analysis of Point-of-Care Immunoassay for Adenoviral Conjunctivitis.
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Johnson SD, Harthan JS, Than T, Migneco MK, Shorter E, Whiteside MM, Morettin CE, Olson CK, Rosemann CA, Margolis MS, Haertter LW, Huecker JB, Rodic-Polic B, Buller RS, Storch GA, Gordon MO, and Hartwick ATE
- Subjects
- Adult, Humans, Immunoassay, Point-of-Care Systems, Sensitivity and Specificity, Adenoviridae Infections diagnosis, Conjunctivitis
- Abstract
Purpose: Accurate diagnosis of adenoviral conjunctivitis (Ad-Cs) is important for timely and appropriate patient management to reduce disease transmission. This study assessed the diagnostic accuracy of a commercially available point-of-care adenovirus immunoassay and determined whether its predictive accuracy is influenced by signal intensities of test result bands., Methods: Point-of-care immunoassay (AdenoPlus) testing and quantitative polymerase chain reaction (qPCR) testing was performed on conjunctival swab samples obtained from eyes of 186 eligible adult participants with presumed infectious conjunctivitis and symptoms of ≤4 days. Masked observers assessed signal intensities of the immunoassay test and control bands using densitometry., Results: Ad-Cs was confirmed by qPCR in 28 of the 56 eyes that tested positive on the AdenoPlus, a 50% positive predictive value (95% confidence interval [CI] = 36.9, 63.1). No adenovirus was detected by qPCR in 128 of 130 eyes that tested negative on AdenoPlus, a 98.5% negative predictive value (CI = 96.3, 100). Sensitivity and specificity were 93% (CI = 84.4, 100) and 82% (CI = 76.0, 88.1), respectively. Viral titers significantly correlated with ratio of test band signal intensities (R2 = 0.32, P = 0.002). Higher positive predictive value was associated with higher densitometry ratios (receiver operating characteristic [ROC] area = 0.71; 95% CI = 0.59, 0.83)., Conclusions: Densitometric analyses suggest that the diagnostic accuracy of AdenoPlus is influenced by the signal intensity of the test result bands. Visual comparison of the test band intensities by clinicians could reduce the false positive rate of point-of-care immunoassays and aid in the diagnosis of viral infections., Translational Relevance: Ratiometric densitometry of point-of-care immunoassays could aid clinicians' decision making in diagnosing infectious diseases, including Ad-Cs.
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- 2021
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136. A Randomized Comparison of Positional Stability: The EZ-Blocker Versus Left-Sided Double-Lumen Endobronchial Tubes in Adult Patients Undergoing Thoracic Surgery.
- Author
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Morris BN, Fernando RJ, Garner CR, Johnson SD, Gardner JC, Marchant BE, Johnson KN, Harris HM, Russell GB, Wudel LJ Jr, and Templeton TW
- Subjects
- Adult, Humans, Intubation, Intratracheal, Prospective Studies, One-Lung Ventilation, Thoracic Surgery, Thoracic Surgical Procedures
- Abstract
Objective: To assess if there is a difference in the repositioning rate of the EZ-Blocker versus a left-sided double-lumen endobronchial tube (DLT) in patients undergoing thoracic surgery and one-lung ventilation., Design: Prospective, randomized., Setting: Single center, university hospital., Participants: One hundred sixty-three thoracic surgery patients., Interventions: Patients were randomized to either EZ-Blocker or a DLT., Measurements and Main Results: The primary outcome was positional stability of either the EZ-Blocker or a left-sided double-lumen endobronchial tube, defined as the number of repositionings per hour of surgery and one-lung ventilation. Secondary outcomes included an ordinal isolation score from 1 to 3, in which 1 was poor, up to 3, which represented excellent isolation, and a visual analog postoperative sore throat score (0-100) on postoperative days (POD) one and two. Rate of repositionings per hour during one-lung ventilation and surgical manipulation in left-sided cases was similar between the two devices: 0.08 ± 0.15 v 0.11 ± 0.3 (p = 0.72). In right-sided cases, the rate of repositioning was higher in the EZ-Blocker group compared with DLT: 0.38 ± 0.65 v 0.09 ± 0.21 (p = 0.03). Overall, mean isolation scores for the EZ-Blocker versus the DLT were 2.76 v 2.92 (p = 0.04) in left-sided cases and 2.70 v 2.83 (p = 0.22) in right-sided cases. Median sore throat scores for left sided cases were 0 v 5 (p = 0.13) POD one and 0 v 5 (p = 0.006) POD two for the EZ-Blocker and left-sided DLT, respectively., Conclusion: For right-sided procedures, the positional stability of the EZ-Blocker is inferior to a DLT. In left-sided cases, the rate of repositioning for the EZ-Blocker and DLT are not statistically different., (Copyright © 2020 Elsevier Inc. All rights reserved.)
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- 2021
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137. Fly Pollination of Kettle Trap Flowers of Riocreuxia torulosa (Ceropegieae-Anisotominae): A Generalized System of Floral Deception.
- Author
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Heiduk A, Meve U, Menzel F, Haenni JP, Tschirnhaus MV, Dötterl S, and Johnson SD
- Abstract
Elaborated kettle trap flowers to temporarily detain pollinators evolved independently in several angiosperm lineages. Intensive research on species of Aristolochia and Ceropegia recently illuminated how these specialized trap flowers attract particular pollinators through chemical deception. Morphologically similar trap flowers evolved in Riocreuxia ; however, no data about floral rewards, pollinators, and chemical ecology were available for this plant group. Here we provide data on pollination ecology and floral chemistry of R. torulosa . Specifically, we determined flower visitors and pollinators, assessed pollen transfer efficiency, and analysed floral scent chemistry. R. torulosa flowers are myiophilous and predominantly pollinated by Nematocera. Pollinating Diptera included, in order of decreasing abundance, male and female Sciaridae, Ceratopogonidae, Scatopsidae, Chloropidae, and Phoridae. Approximately 16% of pollen removed from flowers was successfully exported to conspecific stigmas. The flowers emitted mainly ubiquitous terpenoids, most abundantly linalool, furanoid ( Z )-linalool oxide, and ( E )-β-ocimene-compounds typical of rewarding flowers and fruits. R. torulosa can be considered to use generalized food (and possibly also brood-site) deception to lure small nematocerous Diptera into their flowers. These results suggest that R. torulosa has a less specific pollination system than previously reported for other kettle trap flowers but is nevertheless specialized at the level of Diptera suborder Nematocera.
- Published
- 2021
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138. Sexual deception of a beetle pollinator through floral mimicry.
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Cohen C, Liltved WR, Colville JF, Shuttleworth A, Weissflog J, Svatoš A, Bytebier B, and Johnson SD
- Subjects
- Animals, Bees, Flowers, Insecta, Macrolides, Coleoptera, Diptera, Orchidaceae, Pollination, Wasps
- Abstract
Sexual mimicry is a complex multimodal strategy used by some plants to lure insects to flowers for pollination.
1-4 It is notable for being highly species-specific and is typically mediated by volatiles belonging to a restricted set of chemical compound classes.3 , 4 Well-documented cases involve exploitation of bees and wasps (Hymenoptera)5 , 6 and flies (Diptera).7-9 Although beetles (Coleoptera) are the largest insect order and are well known as pollinators of both early and modern plants,10 , 11 it has been unclear whether they are sexually deceived by plants during flower visits.12 , 13 Here we report the discovery of an unambiguous case of sexual deception of a beetle: male longhorn beetles (Chorothyse hessei, Cerambycidae) pollinate the elaborate insectiform flowers of a rare southern African orchid (Disa forficaria), while exhibiting copulatory behavior including biting the antennae-like petals, curving the abdomen into the hairy lip cleft, and ejaculating sperm. The beetles are strongly attracted by (16S,9Z)-16-ethyl hexadec-9-enolide, a novel macrolide that we isolated from the floral scent. Structure-activity studies14 , 15 confirmed that chirality and other aspects of the structural geometry of the macrolide are critical for the attraction of the male beetles. These results demonstrate a new biological function for plant macrolides and confirm that beetles can be exploited through sexual deception to serve as pollinators., Competing Interests: Declaration of interests The authors declare no competing interests, (Copyright © 2021 Elsevier Inc. All rights reserved.)- Published
- 2021
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139. Success of Masking 5% Povidone-Iodine Treatment: The Reducing Adenoviral Patient Infected Days Study.
- Author
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Whiteside MM, Shorter ES, Margolis MS, Alvi F, Huecker JB, Than TP, Migneco MK, Harthan JS, Morettin CE, Hartwick ATE, Johnson SD, Perera CD, and Gordon MO
- Subjects
- Administration, Ophthalmic, Adolescent, Adult, Double-Blind Method, Female, Humans, Lubricant Eye Drops administration & dosage, Male, Ophthalmic Solutions, Pilot Projects, Treatment Outcome, Young Adult, Adenovirus Infections, Human drug therapy, Anti-Infective Agents, Local therapeutic use, Conjunctivitis, Viral drug therapy, Eye Infections, Viral drug therapy, Povidone-Iodine therapeutic use
- Abstract
Significance: The effectiveness of masking is rarely evaluated or reported in single- or double-masked clinical trials. Knowledge of treatment assignment by participants and clinicians can bias the assessment of treatment efficacy., Purpose: This study aimed to evaluate the effectiveness of masking in a double-masked trial of 5% povidone-iodine for the treatment of adenoviral conjunctivitis., Methods: The Reducing Adenoviral Patient Infected Days study is a double-masked, randomized trial comparing a one-time, in-office administration of 5% povidone-iodine with artificial tears for the treatment of adenoviral conjunctivitis. Masking was assessed by asking participants and masked clinicians at designated time points if they believed the treatment administered was povidone-iodine or artificial tears, or if they were unsure. Adequacy of masking was quantified using a modified Bang Blinding Index., Results: Immediately after treatment, 34% of participants who received povidone-iodine and 69% of those who received artificial tears guessed incorrectly or were unsure of their treatment (modified Bang Indices of 0.31 and -0.38, respectively). On day 4, 38% of the povidone-iodine participants and 52% of the artificial tear participants guessed incorrectly or were unsure of their treatment (modified Bang Indices of 0.24 and -0.05, respectively), indicating adequate and ideal masking. On days 1, 4, 7, 14, and 21, masked clinicians guessed incorrectly or were unsure of treatment in 53%, 50%, 40%, 39%, and 42% among povidone-iodine participants compared with 44%, 35%, 38%, 35%, and 39% among artificial tears participants, respectively. The modified Bang Indices for clinician masking in the povidone-iodine group ranged from -0.05 to 0.25 and from 0.13 to 0.29 in the artificial tears group., Conclusions: Masking of participants and clinicians was adequate. Successful masking increases confidence that subjective measurements are not biased. We recommend quantitative assessment and reporting the effectiveness of masking in ophthalmic clinical trials., Competing Interests: Conflict of Interest Disclosure: None of the authors have reported a financial conflict of interest., (Copyright © 2021 American Academy of Optometry.)
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- 2021
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140. Foods Implicated in U.S. Outbreaks Differ from the Types Most Commonly Consumed.
- Author
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Richardson LC, Cole D, Hoekstra RM, Rajasingham A, Johnson SD, and Bruce BB
- Subjects
- Animals, Disease Outbreaks, Eggs, Food Contamination, Fruit, Humans, Vegetables, Foodborne Diseases epidemiology
- Abstract
Abstract: Foodborne disease outbreak investigations identify foods responsible for illnesses. However, it is not known the degree to which foods implicated in outbreaks reflect the distribution of food consumption in the U.S. population or the risk associated with their consumption. We compared the distribution of 24 categories of foods implicated in outbreaks with the distribution of foods consumed by the U.S. population. Beef, chicken, eggs, fish, herbs, mollusks, pork, sprouts, seeded vegetables, and turkey were implicated in outbreaks significantly more often than expected based on the frequency of their consumption by the general population, suggesting a higher risk of contamination or mishandling from foods in these categories than from foods in other categories. In contrast, pasteurized dairy, fruits, grains and beans, oils and sugars, and root and underground vegetables were less frequently implicated in outbreaks than their frequency of consumption by the general population, suggesting a lower health risk associated with these food categories., (Published 2021 by the International Association for Food Protection. Not subject to U.S. Copyright.)
- Published
- 2021
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141. Optimising backscatter from multiple beam interference.
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O'Donnell L, Padgett MJ, and Johnson SD
- Abstract
Optical sensing applications are usually reliant on the intensity of the measured signal. For remote sensing applications where a target is probed with a laser beam, the sensitivity will be limited by the amount of backscattered light returned from the target to the detector. We demonstrate a method of increasing the signal returned to the detector by illuminating the target with a number of independently controlled beams, where both the position and phase are optimised. We show an improvement in the backscattered signal that is proportional to the number of beams used. The method is demonstrated within a laser microphone, measuring audio signal due to vibrations in surfaces, showing a significant improvement in the signal-to-noise of the measurement.
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- 2021
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142. The relationship of public and private religiosity to African American women caregivers' use of alcohol for coping with caregiving burden.
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Pickard JG, Williams Woodson SL, and Johnson SD
- Subjects
- Adaptation, Psychological, Aged, Cross-Sectional Studies, Female, Humans, Religion, Black or African American, Caregivers
- Abstract
The number of African American women providing unpaid care to an older person is increasing. Multiple stresses are associated with the caregiving experience. This article examines the relationship of both public and private religiosity to the use of alcohol to cope with these stresses. Data were from the Black Rural and Urban Caregivers Mental Health and Functioning Study. This cross-sectional study included 521 midwestern urban ( n = 256) and rural ( n = 265) African American women who were caregivers of dependent African Americans age 65 years and older. Results of heiarchical multinomial logistic regression revealed that those who are younger, those living in an urban area, and those with lower levels of religious attendance were more likely to use alcohol to cope with the stresses of caregiving. Helping professionals can use a strengths perspective, which highlights the importance of emphasizing strengths to increase caregivers' personal power, the development of strong coping skills, and the improvement of social support systems to create a positive approach to self-care with a focus on community building.
- Published
- 2021
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143. Mechanisms of Male-Male Interference during Dispersal of Orchid Pollen.
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Harder LD, Richards SA, Ågren J, and Johnson SD
- Subjects
- Animals, Bees physiology, Orchidaceae physiology, Pollen, Pollination physiology
- Abstract
AbstractSiring success of flowering plants depends on the fates of male gametophytes, which compete for access to stigmas, stylar resources, and ovules. Although rarely considered, pollen may often compete during dispersal, affecting the processes required for export to stigmas: pollen pickup, transport, and deposition. We quantified dispersal interference by tracking bee-mediated dispersal of stained Anacamptis morio (Orchidaceae) pollen from individual donor flowers and inferred the affected dispersal mechanisms on the basis of the fit of a process-based model. During individual trials, all recipient flowers were either emasculated, precluding interference with donor pollen, or intact, adding potentially interfering pollen to the pollinator. The presence of competing pollinaria on bees reduced pickup of additional pollinaria, doubled the overall proportion of lost donor pollen, and reduced total pollen export by 27%. Interference specifically increased loss of donor pollen between successive flower visits and variation in deposition among trials, and it likely also reduced pollen contact with stigmas and pollen deposition when contact occurred. Thus, by altering pollen removal, transport, and deposition, male-male interference during pollen dispersal can significantly-and perhaps commonly-limit plant-siring success.
- Published
- 2021
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144. Floral hosts of leaf-cutter bees (Megachilidae) in a biodiversity hotspot revealed by pollen DNA metabarcoding of historic specimens.
- Author
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Gous A, Eardley CD, Johnson SD, Swanevelder DZH, and Willows-Munro S
- Subjects
- Animals, South Africa, Species Specificity, Bees, Biodiversity, DNA Barcoding, Taxonomic, Flowers, Pollen genetics
- Abstract
South Africa is a megadiverse country with three globally recognised biodiversity hotspots within its borders. Bees in particular show high diversity and endemism in the western part of the country. Not much is currently known about the floral host preferences of indigenous bees in South Africa, with data only available from observational studies. Pollen metabarcoding provides provenance information by utilising DNA analyses instead of floral visitation and traditional microscopic identification to identify pollinator food plants, which can be time consuming and imprecise. In this study, we sampled pollen from leaf-cutter bees (Megachilidae) specimens maintained in a historic insect collection (National Collection of Insects, South Africa) that were originally collected from two florally important areas in South Africa (Succulent Karoo and Savanna) and used metabarcoding to determine pollen provenance. We also sampled pollen from leafcutter bee species with wider distributions, that extend across many different biomes, to determine if these 'generalist' species show relaxed floral host specificity in some biomes. Metabarcoding involved sequencing of the nuclear internal transcribed spacer 2 (ITS2) region. Amplicons were compared to a sequence reference database to assign taxonomic classifications to family level. Sequence reads were also clustered to OTUs based on 97% sequence similarity to estimate numbers of plant species visited. We found no significant difference in the mean number of plant taxa visited in the Succulent Karoo and Savanna regions, but the widespread group visited significantly more floral hosts. Bees from the widespread group were also characterised by a significantly different composition in pollen assemblage. The time since specimens were collected did not have an effect on the mean number of taxa visited by any of the bee species studied. This study highlights national history collections as valuable sources of temporal and spatial biodiversity data., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2021
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145. Food Reward Chemistry Explains a Novel Pollinator Shift and Vestigialization of Long Floral Spurs in an Orchid.
- Author
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Castañeda-Zárate M, Johnson SD, and van der Niet T
- Subjects
- Animals, Bees physiology, Feeding Behavior physiology, Flowers metabolism, Moths physiology, Odorants, Oils, Volatile metabolism, Phylogeny, Plant Oils metabolism, Reward, Adaptation, Physiological, Evolution, Molecular, Flowers chemistry, Orchidaceae physiology, Pollination physiology
- Abstract
During the evolutionary history of flowering plants, transitions between pollinator groups (pollinator shifts) have been frequent,
1 and contributed to the spectacular radiation of angiosperms.2 Although the evolution of floral traits during pollinator shifts has been studied in real time under controlled laboratory conditions,3 it is challenging to study in nature and therefore poorly understood.4-7 Using a comparative, multidisciplinary approach, we dissect the evolution of floral traits during a pollinator shift in the long-spurred African orchid Satyrium longicauda. Phylogenetic analysis and ecological experiments revealed a shift from moth- to oil-collecting bee pollination. Remarkably, flowers of the bee-pollinated form are similar in morphology, color, and overall volatile chemistry to those of moth-pollinated forms, but differ in having spurs that are mostly devoid of nectar, and have an elevated presence of the oil-derived compound diacetin, which oil-collecting bees use as a cue for oil presence.8 Experiments demonstrated that long spurs are critical for pollination of a moth-pollinated form, but are not needed for pollination of the bee-pollinated form. We conclude that the pollinator shift in Satyrium was mediated by a switch in chemistry of the pollinator reward. The ancestral presence of diacetin might have served as a pre-adaptation for bee pollination, whereas the current mismatch between flower morphology and bees is due to the retention of vestigial floral spurs. These results elucidate the sequence of floral evolution in the early stages of pollinator shifts and help to explain the assembly of suites of co-varying traits through pre-adaptation and vestigialization.9-12 ., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)- Published
- 2021
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146. Racial Equity as a Human Rights Issue: Field Agency Practices and Field Instructors' Knowledge and Attitudes.
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McDermott C, Stafford JD, and Johnson SD
- Abstract
Racial equity which, at minimum, is defined as the state in which health, social, and economic outcomes are no longer predicted by race has become a critical issue for social workers who work with and advocate for the rights of marginalized communities. Despite its importance, it remains to be seen if field instructors and the agencies they work for understand racial equity as a human rights issue. Through an anonymous survey, we assessed field instructor's racial equity awareness, knowledge, and understanding and examined actions agencies have taken to address and advance racial equity. It was hypothesized that field instructors who view racial equity as a human right would report promoting and advancing these important concepts with their students and organizations. A total of 170 field instructors accessed the survey through an emailed link in this exploratory effort. Descriptive analyses found that field instructors believe that racial equity is a significant human rights issue and that their agency's culture views racial equity as important; however, issues with time, resources, funding, and expertise to promote racial equity initiatives create obstacles to bring about change. The discussion emphasizes the importance of building capacity among field educators to address racial equity through a human rights lens, which is integral to advancing the collective social work goals of social justice and dismantling systemic oppression., Competing Interests: Conflict of InterestThe authors declare they have no conflicts of interest., (© Springer Nature Switzerland AG 2021.)
- Published
- 2021
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147. Dung mimicry: the function of volatile emissions and corolla patterning in fly-pollinated Wurmbea flowers.
- Author
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Johnson SD, Sivechurran J, Doarsamy S, and Shuttleworth A
- Subjects
- Animals, Feces, Female, Flowers, Pollination, Biological Mimicry, Colchicaceae, Magnoliopsida
- Abstract
It has been suggested that flowers of some angiosperms mimic vertebrate faeces (dung) in order to exploit insect pollinators that utilize faeces as a source of food and/or oviposition sites. We investigated a potential case of mimicry in Wurmbea elatior (Colchicaceae), a lily that exhibits a faecal odour and pattern of dark spots on the corolla. We found that W. elatior is pollinated by a broad assemblage of coprophagous flies and is dependent on pollinator visits for seed production. The flowers emit volatiles that are characteristic of vertebrate faeces, and three of these compounds - skatole, indole, and an unidentified compound - elicited electrophysiological antennal responses from flies. Artificial flowers laced with indole and skatole or skatole alone attracted the same assemblage of flies as was recorded on flowers of W. elatior. Spotted artificial flowers attracted twice as many flies as did those lacking spots. Experimental addition of indole and skatole to flowers of Wurmbea kraussii, a congener with unscented flowers pollinated by hoverflies, induced a shift to an insect visitor assemblage dominated by coprophagous flies. This study clarifies the roles of volatile emissions (particularly skatole) and visual signals in floral dung mimicry., (© 2020 The Authors. New Phytologist © 2020 New Phytologist Trust.)
- Published
- 2020
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148. Diel scent and nectar rhythms of an African orchid in relation to bimodal activity patterns of hawkmoth pollinators.
- Author
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Balducci MG, Van der Niet T, and Johnson SD
- Subjects
- Animals, Flowers, Odorants, Plant Nectar, Pollination, Moths, Orchidaceae
- Abstract
Background and Aims: The temporal dimensions of floral adaptation to pollinators are not yet well understood, partly because we lack accurate information on the diel rhythms of flower visitation for many pollinators. We investigated whether diel patterns of pollinator visitation to flowers of the African woodland orchid Bonatea polypodantha are synchronized with rhythms of floral anthesis, scent emission and nectar availability., Methods: Direct observations and motion-activated cameras were used to identify pollinators of B. polypodantha and to document their activity periods. The timing of pollinaria removal from flowers, emission of scent and availability of nectar was also measured., Results: We found that B. polypodantha is pollinated exclusively by short-tongued hawkmoths. Pollinaria of the orchid are affixed between the labial palps of the moths and brush over the protruding stigmatic arms. The flowers also receive visits by long-tongued hawkmoths, but these act as nectar thieves. Tracking of pollinaria removal from flowers confirmed that pollination occurs only at night. Camera footage revealed a striking crepuscular pattern of foraging by short-tongued hawkmoths with peaks of activity during the twilight periods at dusk and at dawn. In contrast, long-tongued hawkmoths were found to visit flowers throughout the night. Flowers of B. polypodantha exhibit unimodal peaks of anthesis, scent emission (dominated by nitrogenous aromatics) and nectar availability before or around dusk., Conclusions: Flowers of B. polypodantha are pollinated exclusively by short-tongued hawkmoths, which show crepuscular foraging activity at dusk and dawn. Floral phenophases of the orchid are closely synchronized with the peak of pollinator activity at dusk., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2020
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149. Floral Color Variation in Drosera cistiflora Is Associated With Switches in Beetle Pollinator Assemblages.
- Author
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Johnson SD, von Witt CG, and Anderson B
- Abstract
Floral color shifts are thought to be one of the most common evolutionary transitions in plants, and pollinators are often proposed as important selective agents driving these transitions. However, shifts in flower color can also be related to neutral genetic processes or pleiotropy linked with selection via other biotic agents or abiotic factors. Here we ask whether abiotic factors or pollinators provide the best explanation for divergence in flower color among populations of the sundew Drosera cistiflora s.l. (Droseraceae). This species complex in the Greater Cape Floristic Region contains at least five distinctive floral color forms. Abiotic factors do not appear to play a significant role in color determination, as the forms are not specific to a single soil or vegetation type, sometimes co-occur in the same habitat, and maintain their color traits in common-garden and soil switching experiments. Instead, we found strong associations between flower color and the composition of pollinator assemblages which are dominated by hopliine scarab beetles. Pollinator assemblages show geographical structuring, both within and among color forms. This makes it difficult to dissect the roles of geography versus floral traits in explaining pollinator assemblages, but strong pollinator partitioning among color forms at sites where they are sympatric indicates that pollinators may select strongly on color. These results suggest that beetle pollinators are a significant factor in the evolution of D. cistiflora s.l. flower color., (Copyright © 2020 Johnson, von Witt and Anderson.)
- Published
- 2020
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150. Breeding systems of floral colour forms in the Drosera cistiflora species complex.
- Author
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von Witt CG, Anderson B, Durbach IN, and Johnson SD
- Subjects
- Color, Pollination, Seeds, South Africa, Drosera genetics, Flowers physiology, Pigmentation, Plant Breeding
- Abstract
Variation in plant breeding systems has implications for pollinator-mediated selection on floral traits and the ecology of populations. Here we evaluate pollinator contribution to seed production, self-compatibility and pollen limitation in different floral colour forms of Drosera cistiflora sensu lato (Droseraceae). These insectivorous perennial plants are endemic to fynbos and renosterveld vegetation in the Cape Floristic Region of South Africa, and the species complex includes five floral colour forms (pink, purple, red, white and yellow), some of which are known to be pollinated by beetles. Controlled hand-pollination experiments were conducted in 15 populations of D. cistiflora s.l. (two to four populations per floral colour form) to test whether the colour forms vary in their degree of self-compatibility and their ability to produce seeds through autonomous self-fertilization. Yellow-flowered forms were highly self-incompatible, while other floral colour forms exhibited partial self-compatibility. Seed set resulting from autonomous selfing was very low, and pollinator dependence indices were high in all populations. Since hand cross-pollination resulted in greater seed set than open pollination in 13 of the 15 populations, we inferred that seed production is generally pollen-limited. Drosera cistiflora s.l. typically exhibits high levels of pollinator dependence and pollen limitation. This is unusual among Drosera species worldwide and suggests that pollinators are likely to mediate strong selection on attractive traits such as floral colour and size in D. cistiflora s.l. These results also suggest that the floral colour forms of D. cistiflora s.l. which are rare and threatened are likely to be vulnerable to local extinction if mutualisms were to collapse indefinitely., (© 2020 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.)
- Published
- 2020
- Full Text
- View/download PDF
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