Search

Huanglongbing (HLB) is a fatal citrus disease that is currently threatening citrus varieties worldwide. One putative causative agent, Candidatus Liberibacter asiaticus (CLas), is vectored by Diaphorina citri, known as the Asian citrus psyllid (ACP). Understanding the details of CLas infection in HLB disease has been hindered by its Candidatus nature and the inability to confidently detect it in diseased trees during the asymptomatic stage. To identify early changes in citrus metabolism in response to inoculation of CLas using its natural psyllid vector, leaves from Madam Vinous sweet orange (Citrus sinensis (L.) Osbeck) trees were exposed to CLas-positive ACP or CLas-negative ACP and longitudinally analyzed using transcriptomics (RNA sequencing), proteomics (liquid chromatography-tandem mass spectrometry; data available in Dryad: 10.25338/B83H1Z), and metabolomics (proton nuclear magnetic resonance). At 4 weeks postexposure (wpe) to psyllids, the initial HLB plant response was primarily to the ACP and, to a lesser extent, the presence or absence of CLas. Additionally, analysis of 4, 8, 12, and 16 wpe identified 17 genes and one protein as consistently differentially expressed between leaves exposed to CLas-positive ACP versus CLas-negative ACP. This study informs identification of early detection molecular targets and contributes to a broader understanding of vector-transmitted plant pathogen interactions.

Presymptomatic detection of citrus trees infected with Candidatus Liberibacter asiaticus (CLas), the bacterial pathogen associated with Huanglongbing (HLB; citrus greening disease), is critical to controlling the spread of the disease. To test whether infected citrus trees produce systemic signals that may be used for indirect disease detection, lemon (Citrus limon) plants were graft-inoculated with either CLas-infected or control (CLas-) budwood, and leaf samples were longitudinally collected over 46 weeks and analyzed for plant changes associated with CLas infection. RNA, protein, and metabolite samples extracted from leaves were analyzed using RNA-Seq, mass spectrometry, and 1H NMR spectroscopy, respectively. Significant differences in specific transcripts, proteins, and metabolites were observed between CLas-infected and control plants as early as 2 weeks post graft (wpg). The most dramatic differences between the transcriptome and proteome of CLas-infected and control plants were observed at 10 wpg, including coordinated increases in transcripts and proteins of citrus orthologs of known plant defense genes. This integrated approach to quantifying plant molecular changes in leaves of CLas-infected plants supports the development of diagnostic technology for presymptomatic or early disease detection as part of efforts to control the spread of HLB into uninfected citrus groves.

Huanglongbing (HLB) is a deadly, incurable citrus disease putatively caused by the unculturable bacterium, 'Candidatus Liberibacter asiaticus' (CLas), and transmitted by Diaphorina citri. Prior studies suggest D. citri transmits CLas in a circulative and propagative manner; however, the precise interactions necessary for CLas transmission remain unknown, and the impact of insect sex on D. citri-CLas interactions is poorly understood despite reports of sex-dependent susceptibilities to CLas. We analyzed the transcriptome, proteome, metabolome, and microbiome of male and female adult D. citri reared on healthy or CLas-infected Citrus medica to determine shared and sex-specific responses of D. citri and its endosymbionts to CLas exposure. More sex-specific than shared D. citri responses to CLas were observed, despite there being no difference between males and females in CLas density or relative abundance. CLas exposure altered the abundance of proteins involved in immunity and cellular and oxidative stress in a sex-dependent manner. CLas exposure impacted cuticular proteins and enzymes involved in chitin degradation, as well as energy metabolism and abundance of the endosymbiont 'Candidatus Profftella armatura' in both sexes similarly. Notably, diaphorin, a toxic Profftella-derived metabolite, was more abundant in both sexes with CLas exposure. The responses reported here resulted from a combination of CLas colonization of D. citri as well as the effect of CLas infection on C. medica. Elucidating these impacts on D. citri and their endosymbionts contributes to our understanding of the HLB pathosystem and identifies the responses potentially critical to limiting or promoting CLas acquisition and propagation in both sexes.

The current three sigma tension in the unitarity test of the Cabbibo-Kobayashi-Maskawa (CKM) matrix is a notable problem with the Standard Model of elementary particle physics. A long-standing goal of the study of free neutron beta decay is to better determine the CKM element Vud through measurements of the neutron lifetime and a decay correlation parameter. The Nab collaboration intends to measure a, the neutrino-electron correlation, with accuracy sufficient for a competitive evaluation of Vud based on neutron decay data alone. This paper gives a status report and an outlook.

This study investigates climate change perceptions of secondary science teachers in a Blue state and a Red state. A total of 832 secondary science teachers, 456 from California, and 376 from Texas public schools responded to an online questionnaire regarding their climate change perceptions. Findings indicate that a significant proportion of teachers in both states lack adequate knowledge and have misconceptions about basic climate change concepts. However, California teachers have a better understanding and fewer misconceptions about the greenhouse effect. More California than Texas teachers emphasize the scientific consensus about climate change anthropogenic causes, while more Texas than California teachers send conflicting messages by emphasizing climate change's natural causes and scientific consensus about its anthropogenic causes. Study findings reveal a significant association between teachers' political orientation and their views of the scientific consensus about climate change anthropogenic causes. The notable differences in teachers' understanding of climate change, instructional approaches, and views of the scientific consensus between responding California and Texas teachers suggest that climate change is taught differently in the two states. Findings highlight the need for additional in-service training to improve teachers' climate knowledge, climate science communication, the epistemology of science knowledge, and the ethics of professional responsibility.

Globally, the number of drug users and the proportion of the drug using population has increased from 210 million in 2009 to 269 million in 2019. Several studies suggest that music festival attendees are more likely to abuse illicit substances and have a high‐risk profile. Consequently, it is crucial to develop robust field drug analysis methods that facilitate harm reduction and drug monitoring. The work presented in this report aimed at developing and validating qualitative analytical methods for 3,4‐methylenedioxymethamphetamine, 4‐bromo‐2,5‐dimethoxyphenethylamine (2C‐B), ketamine and N‐ethylpentylone on two portable gas chromatography–mass spectrometry (GC–MS) systems: Griffin G510 (Teledyne FLIR, West Lafayette, IN) and Torion T‐9 (PerkinElmer, Shelton, CT). The diagnostic ability of the mobile GC–MS units was assessed on 200 samples in total, seized at two large summer music festivals in the United Kingdom. The method validation process included selectivity/specificity, limit of identification, carry‐over, ruggedness/robustness, and inter‐ and intra‐day precision (repeatability and reproducibility). The Griffin G510 demonstrated a limit of identification from 1 mg/mL for 2C‐B to 0.063 mg/mL for ketamine and good ruggedness and precision results. The precision for 2C‐B using the Torion T‐9 was poorer than for the Griffin G510, but equivalent for the other compounds tested. Correct identifications (versus benchtop GC–MS) for the two festivals were 85%–86% and 74%–83% for the Griffin G510 and the Torion T‐9, respectively. The two portable instruments were able to adequately cover current on‐site drug‐testing analytical gaps and proved to be a powerful addition to the on‐site drug analysis techniques. [ABSTRACT FROM AUTHOR]

Abstract Background Recent genomic analyses of arthropod defense mechanisms suggest conservation of key elements underlying responses to pathogens, parasites and stresses. At the center of pathogen-induced immune responses are signaling pathways triggered by the recognition of fungal, bacterial and viral signatures. These pathways result in the production of response molecules, such as antimicrobial peptides and lysozymes, which degrade or destroy invaders. Using the recently sequenced genome of the pea aphid (Acyrthosiphon pisum), we conducted the first extensive annotation of the immune and stress gene repertoire of a hemipterous insect, which is phylogenetically distantly related to previously characterized insects models. Results Strikingly, pea aphids appear to be missing genes present in insect genomes characterized to date and thought critical for recognition, signaling and killing of microbes. In line with results of gene annotation, experimental analyses designed to characterize immune response through the isolation of RNA transcripts and proteins from immune-challenged pea aphids uncovered few immune-related products. Gene expression studies, however, indicated some expression of immune and stress-related genes. Conclusions The absence of genes suspected to be essential for the insect immune response suggests that the traditional view of insect immunity may not be as broadly applicable as once thought. The limitations of the aphid immune system may be representative of a broad range of insects, or may be aphid specific. We suggest that several aspects of the aphid life style, such as their association with microbial symbionts, could facilitate survival without strong immune protection.

In practice, sustainable development is the use of natural resources in a manner that allows ecosystems to continue to function as natural ecosystems and biotic and abiotic interactions to maintain checks and balances are homeostatic. Historically, human activity has led to modification of nature that leads to (1) economic development, (2) biotic simplification (e.g., loss of biodiversity and simplified food chains), and (3) abiotic degradation (e.g., large changes in nutrient or light availability). Many experts believe that further biotic simplification and abiotic degradation are no longer sustainable, that the conflict between development and environment is the key to the quality of future human life on the planet, and that sustainability education should begin with young children. Thus, the central sustainable development focus is to balance quality of life with quality of the environment. The focus of the activity described in this article is to introduce and understand the concept of sustainable development by using ideas found in "The Lorax." While the activity as it is written is best suited for fifth grade, it has been used with minimal modification in grades 3-8. This activity is typically used as an introductory activity for a unit of instruction on sustainability and environmental problems, with appropriate follow-up activities tailored to meet specific school contexts. The activity is also suitable for use following lessons and activities on energy in both formal and informal (afterschool science clubs) settings. The recommended way of beginning this activity is small-group read-alouds using the Readers' Theater format. This type of integrated curricular reading is supported by both the anchor and grade-level standards of the "Common Core English Language Arts Standards" (CCSS-ELA). A project rubric and discussion sheet is available at www.nsta.org/SC1603.

Increasing popularity and known shortfalls in the regulation of electronic cigarettes (ECs) emphasises the urgent need for closer content monitoring and for comprehensible information on their possible health effects. This study investigated components of EC liquids in samples submitted from 2014 to 2021 and discussed the trends driven by legislation changes. Samples originating from prisoners, teenagers and 'test purchases' of commercially available ECs were analysed by gas chromatography‐mass spectrometry (GC‐MS). For those containing delta‐9‐tetrahydrocannabinol (THC) and/or cannabidiol (CBD), the content of these components was quantified by liquid chromatography with quadrupole time‐of‐flight mass spectrometry (LC‐QTOF‐MS) to show variation of these compounds in EC liquids; 112 EC liquids were included in this study. Nicotine was detected in 87 (78%) of the EC liquids analysed. Twenty‐two, including samples from before and after introduction of the UK Psychoactive Substances Act (2016), contained one or more synthetic cannabinoid receptor agonist (SCRA). THC was detected in only 11 samples, whereas a single sample was found to contain CBD only. Six samples contained a mixture of THC and CBD. In all cases where information was available, the THC/CBD content was less than that stated on the product label. The data collected showed great variation in EC liquid content. Therefore, it is important that users are educated regarding risks associated with EC use. Additionally, substances now controlled under both the UK Misuse of Drugs Act and Psychoactive Substances Act were present. These substances each carry a potential risk to health, which is possibly exacerbated if multiple compounds are inhaled concomitantly. [ABSTRACT FROM AUTHOR]