Search

When someone has been shot or stabbed in the chest, time is of the essence. Here's what you need to know about the life-threatening complications to look for and the immediate treatment you'll need to initiate. [ABSTRACT FROM AUTHOR]

Peer review is an important part of the scientific publishing process that serves as a key quality control step. Learning that scientific publications go through peer review builds scientific literacy and may increase trust in published findings. Though the publication and peer review process is an established part of the practice of communicating science, this topic is not commonly taught at the undergraduate level, even in classes that regularly require students to read primary literature or author manuscripts. Often, undergraduate course lessons on peer review focus on the practice of performing peer review on other students' writing rather than explaining how this process works for independent scientists publishing their novel work as primary literature articles. As a result, there is a need for more resources related to teaching about publication and peer review. This work presents a plan for out-of-class reading and an in-class lesson on peer review practices in biology. In this module, students learn the order of events in scientific publishing and consider the relationship between peer review and public trust in science by analyzing survey data. Students completing this activity reported knowledge gains related to scientific publishing and peer review and demonstrated their knowledge on an in-class assessment. Though this activity was developed for a biochemistry course, it may be implemented in various life sciences classes from introductory to advanced levels to improve student scientific literacy., Competing Interests: The author declares no conflict of interest., (Copyright © 2023 Barry.)

In mammals, the conserved telomere binding protein Rap1 serves a diverse set of nontelomeric functions, including activation of the NF-kB signaling pathway, maintenance of metabolic function in vivo, and transcriptional regulation. Here, we uncover the mechanism by which Rap1 modulates gene expression. Using a separation-of-function allele, we show that Rap1 transcriptional regulation is largely independent of TRF2-mediated binding to telomeres and does not involve direct binding to genomic loci. Instead, Rap1 interacts with the TIP60/p400 complex and modulates its histone acetyltransferase activity. Notably, we show that deletion of Rap1 in mouse embryonic stem cells increases the fraction of two-cell-like cells. Specifically, Rap1 enhances the repressive activity of Tip60/p400 across a subset of two-cell-stage genes, including Zscan4 and the endogenous retrovirus MERVL. Preferential up-regulation of genes proximal to MERVL elements in Rap1-deficient settings implicates these endogenous retroviral elements in the derepression of proximal genes. Altogether, our study reveals an unprecedented link between Rap1 and the TIP60/p400 complex in the regulation of pluripotency., (© 2022 Barry et al.; Published by Cold Spring Harbor Laboratory Press.)

Avibacterium paragallinarum (historically called Hemophilus paragallinarum ) causes infectious coryza (IC), which is an acute respiratory disease of chickens. Recently, outbreaks of IC have been reported in Pennsylvania (PA) in broilers, layer pullets, and laying hens, causing significant respiratory disease and production losses. A tentative diagnosis of IC can be made based on history, clinical signs, and characteristic gross lesions. However, isolation and identification of the organism are required for a definitive diagnosis. Major challenges with the bacteriological diagnosis of A. paragallinarum include that the organism is difficult to isolate, slow-growing, and can only be successfully isolated during the acute stage of infection and secondary bacterial infections are also common. As there were very limited whole genomes of A. paragallinarum in the public databases, we carried out whole-genome sequencing (WGS) of PA isolates and based on the WGS data analysis; we designed a novel probe-based PCR assay targeting a highly conserved sequence in the recN , the DNA repair protein gene of A. paragallinarum . The assay includes an internal control, with a limit of detection (LOD) of 3.93 genomic copies. The PCR efficiency ranged between 90 and 97%, and diagnostic sensitivity of 98.5% compared with conventional gel-based PCR. The test was highly specific, and no cross-reactivity was observed with other species of Avibacterium and a range of other common poultry respiratory viral and bacterial pathogens. Real-time PCR testing on 419 clinical samples from suspected flocks yielded 94 positives and 365 negatives in agreement with diagnostic bacterial culture-based detection. We also compared the recN PCR assay with a previous HPG-2 based real-time PCR assay which showed a PCR efficiency of 79%., 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 Kuchipudi, Yon, Surendran Nair, Byukusenge, Barry, Nissly, Williams, Pierre, Mathews, Walner-Pendleton, Dunn, Barnhart, Loughrey, Davison, Kelly, Tewari and Jayarao.)

This study examined the impact of Syrian refugees on 1 area of the Canadian health care sector. We predicted that pediatric hematology clinics across Canada would see a spike in their Syrian refugee patient population in proportion to their recent migration and, as a result, an increase in perceived workload. Data on the number of refugee patients, types of diseases, and perceived workload were gathered from hematology clinics across Canada using a clinical survey (Supplemental Digital Content 1, http://links.lww.com/JPHO/A315). The results showed that Ontario had the most Syrian refugee patients, followed by the Quebec, Western Canadian, and Atlantic regions. The results also showed that perceived workload ranged from "no increase" (4 programs) to "minimal increase" <25% (1 program), "moderate increase" 25% to 75% (4 programs), and "significant increase" >75% (3 programs, 2 of which had no transfusion-dependent thalassemia patients before the immigration).

Mammalian cells have evolved multiple pathways to repair DNA double strand breaks (DSBs) and ensure genome stability. In addition to non-homologous end-joining (NHEJ) and homologous recombination (HR), cells evolved an error-prone repair pathway termed microhomology-mediated end joining (MMEJ). The mutagenic outcome of MMEJ derives from the activity of DNA polymerase theta (Polθ) - a multidomain enzyme that is minimally expressed in normal tissue but overexpressed in tumors. Polθ expression is particularly crucial for the proliferation of HR deficient cancer cells. As a result, this mutagenic repair emerged as an attractive target for cancer therapy, and inhibitors are currently in pre-clinical development. Here, we review the multifunctionality of this enigmatic polymerase, focusing on its role during DSB repair in mammalian cells and its impact on cancer genomes., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Purpose: The purpose of this study was to assess impact of operator positioning on the development of musculoskeletal disorders (MSDs) and workforce issues among practicing dental hygienists in the state of Mississippi. Methods: The sample consisted of all dental hygienists (n=1,553) licensed in the state of Mississippi. A modified 47 item, online version of the Standardized Nordic Questionnaire was used to document the following: types of MSDs, practice history, operator positioning, ergonomic work habits and the impact of MSDs on workforce issues. Descriptive statistics were used to analyze practice history and work habits. Chi-square analysis examined the relationship between operator positioning and MSDs as well as the relationship between the onset of MSDs and their impact on patient workload, work hours, time off from work, and ability to practice clinical dental hygiene. Survival analyses were used to test the onset of MSDs in relationship to operator positioning. Results: The survey yielded a 22% (n=338) response rate. There was no significant difference in the prevalence of MSDs between those sitting in front of the patient as compared to those sitting behind the patient (PL) (χ 2 (1) = 1.67, p=0.196), although respondents sitting behind the patient reported developing their MSDs earlier (χ 2 (1) = 3.92, p=0.048). Of the participants who had practiced 15 or more years, 85% reported developing MSDs. However, only 13% reported ever having to modify their patient load. Sixteen percent reported reducing work hours and 21% reported taking time off from work due to MSDs. Conclusions: Regardless of the operator position used, the majority of practicing dental hygienists surveyed developed MSDs earlier than has been previously reported in the literature. Workforce related issues were not shown to have a negative impact on this study population., (Copyright © 2017 The American Dental Hygienists’ Association.)

Whole-exome sequencing of cell-free DNA (cfDNA) could enable comprehensive profiling of tumors from blood but the genome-wide concordance between cfDNA and tumor biopsies is uncertain. Here we report ichorCNA, software that quantifies tumor content in cfDNA from 0.1× coverage whole-genome sequencing data without prior knowledge of tumor mutations. We apply ichorCNA to 1439 blood samples from 520 patients with metastatic prostate or breast cancers. In the earliest tested sample for each patient, 34% of patients have ≥10% tumor-derived cfDNA, sufficient for standard coverage whole-exome sequencing. Using whole-exome sequencing, we validate the concordance of clonal somatic mutations (88%), copy number alterations (80%), mutational signatures, and neoantigens between cfDNA and matched tumor biopsies from 41 patients with ≥10% cfDNA tumor content. In summary, we provide methods to identify patients eligible for comprehensive cfDNA profiling, revealing its applicability to many patients, and demonstrate high concordance of cfDNA and metastatic tumor whole-exome sequencing.

Classical swine fever (CSF) is a highly contagious and potentially fatal disease of domestic pigs. Classical swine fever is routinely diagnosed by clinical signs, serology, detection of CSF virus (CSFV) nucleic acid by PCR and virus isolation. Most of the current CSF diagnostic methods are expensive and have an extended turnaround time. In the majority of the CSF endemic countries, lack of easy access to diagnostic facilities is a major problem for swine producers trying to obtain early diagnosis and often results in the entire herd being infected. The acute form of CSF can show non-specific signs of illness, leaving CSF often undiagnosed. Hence there is an urgent need for a rapid and reliable pen side diagnostic assay for the better detection and control of this economically important disease of swine. We developed an immuno-chromatographic lateral flow assay (LFA) for on the farm detection of CSFV. A CSFV isolate [CSFV/AP/TRP2/2009 (TS2)] of genotype 1.1 was used for the production of monoclonal antibodies (mAbs) for the LFA's development. The virus detection level of the LFA device was 36.8 TCID 50 /ml of CSFV. The sensitivity and specificity of LFA in comparison with PCR were 80.36% and 87.10%, respectively. The positive and negative predictive values of the LFA device were 91.84% and 87.10%, respectively. In conclusion, the CSFV-LFA is a reliable and convenient resource for preliminary on the farm detection of classic swine fever.

Background: The efficacy of protein-conjugated pneumococcal polysaccharide vaccines has been well characterized for children. The level of protection conferred by unconjugated polysaccharide vaccines remains less clear, particularly for elderly individuals who have had prior antigenic experience through immunization with unconjugated polysaccharide vaccines or natural exposure to Streptococcus pneumoniae., Methods: We compared the magnitude, diversity and genetic biases of antigen-specific memory B cells in two groups of adult cynomolgus macaques that were immunized with a 7-valent conjugated vaccine and boosted after five years with either a 13-valent pneumococcal polysaccharide conjugate vaccine (13vPnC) or a 23-valent unconjugated pneumococcal polysaccharide vaccine (23vPS) using microengraving (a single-cell analysis method) and single-cell RT-PCR., Results: Seven days after boosting, the mean frequency of antigen-specific memory B cells was significantly increased in macaques vaccinated with 13vPnC compared to those receiving 23vPS. The 13vPnC-vaccinated macaques also exhibited a more even distribution of antibody specificities to four polysaccharides in the vaccine (PS4, 6B, 14, 23F) that were examined. However, single-cell analysis of the antibody variable region sequences from antigen-specific B cells elicited by unconjugated and conjugated vaccines indicated that both the germline gene segments forming the heavy chains and the average lengths of the Complementary Determining Region 3 (CDR3) were similar., Conclusions: Our results confirm that distinctive differences can manifest between antigen-specific memory B cell repertoires in nonhuman primates immunized with conjugated and unconjugated pneumococcal polysaccharide vaccines. The study also supports the notion that the conjugated vaccines have a favorable profile in terms of both the frequency and breadth of the anamnestic response among antigen-specific memory B cells.

Chromatin exhibits increased mobility on DNA damage, but the biophysical basis for this behavior remains unknown. To explore the mechanisms that drive DNA damage-induced chromosome mobility, we use single-particle tracking of tagged chromosomal loci during interphase in live yeast cells together with polymer models of chromatin chains. Telomeres become mobilized from sites on the nuclear envelope and the pericentromere expands after exposure to DNA-damaging agents. The magnitude of chromatin mobility induced by a single double-strand break requires active microtubule function. These findings reveal how relaxation of external tethers to the nuclear envelope and internal chromatin-chromatin tethers, together with microtubule dynamics, can mobilize the genome in response to DNA damage., (© 2017 Lawrimore et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).)

The universally conserved enzyme CTP synthase (CTPS) forms filaments in bacteria and eukaryotes. In bacteria, polymerization inhibits CTPS activity and is required for nucleotide homeostasis. Here we show that for human CTPS, polymerization increases catalytic activity. The cryo-EM structures of bacterial and human CTPS filaments differ considerably in overall architecture and in the conformation of the CTPS protomer, explaining the divergent consequences of polymerization on activity. The structure of human CTPS filament, the first structure of the full-length human enzyme, reveals a novel active conformation. The filament structures elucidate allosteric mechanisms of assembly and regulation that rely on a conserved conformational equilibrium. The findings may provide a mechanism for increasing human CTPS activity in response to metabolic state and challenge the assumption that metabolic filaments are generally storage forms of inactive enzymes. Allosteric regulation of CTPS polymerization by ligands likely represents a fundamental mechanism underlying assembly of other metabolic filaments.

Resolving how the early signaling events initiated by cell-cell interactions are transduced into diverse functional outcomes necessitates correlated measurements at various stages. Typical approaches that rely on bulk cocultures and population-wide correlations, however, only reveal these relationships broadly at the population level, not within each individual cell. Here, we present a microfluidics-based cell-cell interaction assay that enables longitudinal investigation of lymphocyte interactions at the single-cell level through microfluidic cell pairing, on-chip culture, and multiparameter assays, and allows recovery of desired cell pairs by micromanipulation for off-chip culture and analyses. Well-defined initiation of interactions enables probing cellular responses from the very onset, permitting single-cell correlation analyses between early signaling dynamics and later-stage functional outcomes within same cells. We demonstrate the utility of this microfluidic assay with natural killer cells interacting with tumor cells, and our findings suggest a possible role for the strength of early calcium signaling in selective coordination of subsequent cytotoxicity and IFN-gamma production. Collectively, our experiments demonstrate that this new approach is well-suited for resolving the relationships between complex immune responses within each individual cell.

Over evolutionary time, Wolbachia has been repeatedly transferred between host species contributing to the widespread distribution of the symbiont in arthropods. For novel infections to be maintained, Wolbachia must infect the female germ line after being acquired by horizontal transfer. Although mechanistic examples of horizontal transfer exist, there is a poor understanding of factors that lead to successful vertical maintenance of the acquired infection. Using Anopheles mosquitoes (which are naturally uninfected by Wolbachia) we demonstrate that the native mosquito microbiota is a major barrier to vertical transmission of a horizontally acquired Wolbachia infection. After injection into adult Anopheles gambiae, some strains of Wolbachia invade the germ line, but are poorly transmitted to the next generation. In Anopheles stephensi, Wolbachia infection elicited massive blood meal-induced mortality, preventing development of progeny. Manipulation of the mosquito microbiota by antibiotic treatment resulted in perfect maternal transmission at significantly elevated titers of the wAlbB Wolbachia strain in A. gambiae, and alleviated blood meal-induced mortality in A. stephensi enabling production of Wolbachia-infected offspring. Microbiome analysis using high-throughput sequencing identified that the bacterium Asaia was significantly reduced by antibiotic treatment in both mosquito species. Supplementation of an antibiotic-resistant mutant of Asaia to antibiotic-treated mosquitoes completely inhibited Wolbachia transmission and partly contributed to blood meal-induced mortality. These data suggest that the components of the native mosquito microbiota can impede Wolbachia transmission in Anopheles. Incompatibility between the microbiota and Wolbachia may in part explain why some hosts are uninfected by this endosymbiont in nature.

CTP Synthetase (CtpS) is a universally conserved and essential metabolic enzyme. While many enzymes form small oligomers, CtpS forms large-scale filamentous structures of unknown function in prokaryotes and eukaryotes. By simultaneously monitoring CtpS polymerization and enzymatic activity, we show that polymerization inhibits activity, and CtpS's product, CTP, induces assembly. To understand how assembly inhibits activity, we used electron microscopy to define the structure of CtpS polymers. This structure suggests that polymerization sterically hinders a conformational change necessary for CtpS activity. Structure-guided mutagenesis and mathematical modeling further indicate that coupling activity to polymerization promotes cooperative catalytic regulation. This previously uncharacterized regulatory mechanism is important for cellular function since a mutant that disrupts CtpS polymerization disrupts E. coli growth and metabolic regulation without reducing CTP levels. We propose that regulation by large-scale polymerization enables ultrasensitive control of enzymatic activity while storing an enzyme subpopulation in a conformationally restricted form that is readily activatable., (Copyright © 2014, Barry et al.)

The organization of chromosomes into territories plays an important role in a wide range of cellular processes, including gene expression, transcription, and DNA repair. Current understanding has largely excluded the spatiotemporal dynamic fluctuations of the chromatin polymer. We combine in vivo chromatin motion analysis with mathematical modeling to elucidate the physical properties that underlie the formation and fluctuations of territories. Chromosome motion varies in predicted ways along the length of the chromosome, dependent on tethering at the centromere. Detachment of a tether upon inactivation of the centromere results in increased spatial mobility. A confined bead-spring chain tethered at both ends provides a mechanism to generate observed variations in local mobility as a function of distance from the tether. These predictions are realized in experimentally determined higher effective spring constants closer to the centromere. The dynamic fluctuations and territorial organization of chromosomes are, in part, dictated by tethering at the centromere., (Copyright © 2013 Elsevier Inc. All rights reserved.)

The bacterial cytoskeleton is composed of a complex and diverse group of proteins that self-assemble into linear filaments. These filaments support and organize cellular architecture and provide a dynamic network controlling transport and localization within the cell. Here, we review recent discoveries related to a newly appreciated class of self-assembling proteins that expand our view of the bacterial cytoskeleton and provide potential explanations for its evolutionary origins. Specifically, several types of metabolic enzymes can form structures similar to established cytoskeletal filaments and, in some cases, these structures have been repurposed for structural uses independent of their normal roles. The behaviors of these enzymes suggest that some modern cytoskeletal proteins may have evolved from dual-role proteins with catalytic and structural functions., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Numerous surveys identify the occurrence of musculoskeletal complaints as a concern in dentistry. However, no longitudinal data exist to indicate whether postural changes occur as a result of practicing dental hygiene. The purpose of this preliminary, four-year longitudinal study was to investigate whether any postural changes developed during the hygienists' clinical education and/or during subsequent dental hygiene practice after one and/or two years. It was anticipated that the awkward positions and intense physical demands placed on hygienists might initiate musculoskeletal problems, but that no postural changes would occur over this short period of time. Nine of 10 dental hygienists in the graduating class of 1987 were surveyed for existing musculoskeletal complaints, and the subjects were photographed for a measurement of postural change. Responses from participants indicated an increase in musculoskeletal-related complaints in each of the six areas investigated. The photographic findings indicated that one of the nine hygienists showed an increase in forward head posture, a postural change.

Murine hybridoma cells that produce monoclonal antibody directed against human fibronectin have been cultured in VITAFIBER II and VITAFIBER V hollow fiber bioreactors using defined, serum-free WRC 935 medium. During a two-week growth period, following inoculation of the bioreactors, the cells proliferated to an extent where the bioreactor was filled with cultured cells. Using a 5 sq. ft. VITAFIBER V bioreactor, over 15 grams of antibody were produced during the 40 days of the experiment. This antibody was greater than 95% IgG. During the production period, this packed mass of cells produced 579 +/- 15 mg IgG per day. Because the medium is formulated for air equilibration and high cell densities, WRC 935 medium is especially useful for production of gram quantities of monoclonal antibodies using continuous feed hollow fiber bioreactor cell culture systems.