2,251 research outputs found
Tegument Assembly and Secondary Envelopment of Alphaherpesviruses.
Alphaherpesviruses like herpes simplex virus are large DNA viruses characterized by their ability to establish lifelong latent infection in neurons. As for all herpesviruses, alphaherpesvirus virions contain a protein-rich layer called "tegument" that links the DNA-containing capsid to the glycoprotein-studded membrane envelope. Tegument proteins mediate a diverse range of functions during the virus lifecycle, including modulation of the host-cell environment immediately after entry, transport of virus capsids to the nucleus during infection, and wrapping of cytoplasmic capsids with membranes (secondary envelopment) during virion assembly. Eleven tegument proteins that are conserved across alphaherpesviruses have been implicated in the formation of the tegument layer or in secondary envelopment. Tegument is assembled via a dense network of interactions between tegument proteins, with the redundancy of these interactions making it challenging to determine the precise function of any specific tegument protein. However, recent studies have made great headway in defining the interactions between tegument proteins, conserved across alphaherpesviruses, which facilitate tegument assembly and secondary envelopment. We summarize these recent advances and review what remains to be learned about the molecular interactions required to assemble mature alphaherpesvirus virions following the release of capsids from infected cell nuclei.HSV-1 research in the laboratory of CMC is supported by the Leverhulme Trust (Grant RPG-2012-793) and the Biotechnology and Biological Sciences Research Council (Grant BB/M021424/1). SCG is a Sir Henry Dale Fellow jointly funded by the Wellcome Trust and the Royal Society (Grant Number 098406/Z/12/Z)This is the final version of the article. It first appeared from MDPI via http://dx.doi.org/10.3390/v709286
Evaluating Amazon\u27s Mechanical Turk as a Tool for Experimental Behavioral Research
Amazon Mechanical Turk (AMT) is an online crowdsourcing service where anonymous online workers complete web-based tasks for small sums of money. The service has attracted attention from experimental psychologists interested in gathering human subject data more efficiently. However, relative to traditional laboratory studies, many aspects of the testing environment are not under the experimenter\u27s control. In this paper, we attempt to empirically evaluate the fidelity of the AMT system for use in cognitive behavioral experiments. These types of experiment differ from simple surveys in that they require multiple trials, sustained attention from participants, comprehension of complex instructions, and millisecond accuracy for response recording and stimulus presentation. We replicate a diverse body of tasks from experimental psychology including the Stroop, Switching, Flanker, Simon, Posner Cuing, attentional blink, subliminal priming, and category learning tasks using participants recruited using AMT. While most of replications were qualitatively successful and validated the approach of collecting data anonymously online using a web-browser, others revealed disparity between laboratory results and online results. A number of important lessons were encountered in the process of conducting these replications that should be of value to other researchers
Sharing and organizing research products as R packages
A consensus on the importance of open data and reproducible code is emerging. How should data and code be shared to maximize the key desiderata of reproducibility, permanence, and accessibility? Research assets should be stored persistently in formats that are not software restrictive, and documented so that others can reproduce and extend the required computations. The sharing method should be easy to adopt by already busy researchers. We suggest the R package standard as a solution for creating, curating, and communicating research assets. The R package standard, with extensions discussed herein, provides a format for assets and metadata that satisfies the above desiderata, facilitates reproducibility, open access, and sharing of materials through online platforms like GitHub and Open Science Framework. We discuss a stack of R resources that help users create reproducible collections of research assets, from experiments to manuscripts, in the RStudio interface. We created an R package, vertical, to help researchers incorporate these tools into their workflows, and discuss its functionality at length in an online supplement. Together, these tools may increase the reproducibility and openness of psychological science
Risk factors for human acute leptospirosis in northern Tanzania
Introduction:
Leptospirosis is a major cause of febrile illness in Africa but little is known about risk factors for human infection. We conducted a cross-sectional study to investigate risk factors for acute leptospirosis and Leptospira seropositivity among patients with fever attending referral hospitals in northern Tanzania.
Methods:
We enrolled patients with fever from two referral hospitals in Moshi, Tanzania, 2012ā2014, and performed Leptospira microscopic agglutination testing on acute and convalescent serum. Cases of acute leptospirosis were participants with a four-fold rise in antibody titers, or a single reciprocal titer ā„800. Seropositive participants required a single titer ā„100, and controls had titers <100 in both acute and convalescent samples. We administered a questionnaire to assess risk behaviors over the preceding 30 days. We created cumulative scales of exposure to livestock urine, rodents, and surface water, and calculated odds ratios (OR) for individual behaviors and for cumulative exposure variables.
Results:
We identified 24 acute cases, 252 seropositive participants, and 592 controls. Rice farming (OR 14.6), cleaning cattle waste (OR 4.3), feeding cattle (OR 3.9), farm work (OR 3.3), and an increasing cattle urine exposure score (OR 1.2 per point) were associated with acute leptospirosis.
Conclusions:
In our population, exposure to cattle and rice farming were risk factors for acute leptospirosis. Although further data is needed, these results suggest that cattle may be an important source of human leptospirosis. Further investigation is needed to explore the potential for control of livestock Leptospira infection to reduce human disease
Risk factors for human brucellosis in northern Tanzania
Little is known about the epidemiology of human brucellosis in sub-Saharan Africa. This hampers prevention and control efforts at the individual and population levels. To evaluate risk factors for brucellosis in northern Tanzania, we conducted a study of patients presenting with fever to two hospitals in Moshi, Tanzania. Serum taken at enrollment and at 4ā6 week follow-up was tested by Brucella microagglutination test. Among participants with a clinically compatible illness, confirmed brucellosis cases were defined as having a ā„ 4-fold rise in agglutination titer between paired sera or a blood culture positive for Brucella spp., and probable brucellosis cases were defined as having a single reciprocal titer ā„ 160. Controls had reciprocal titers < 20 in paired sera. We collected demographic and clinical information and administered a risk factor questionnaire. Of 562 participants in the analysis, 50 (8.9%) had confirmed or probable brucellosis. Multivariable analysis showed that risk factors for brucellosis included assisting goat or sheep births (Odds ratio [OR] 5.9, 95% confidence interval [CI] 1.4, 24.6) and having contact with cattle (OR 1.2, 95% CI 1.0, 1.4). Consuming boiled or pasteurized dairy products was protective against brucellosis (OR 0.12, 95% CI 0.02, 0.93). No participants received a clinical diagnosis of brucellosis from their healthcare providers. The under-recognition of brucellosis by healthcare workers could be addressed with clinician education and better access to brucellosis diagnostic tests. Interventions focused on protecting livestock keepers, especially those who assist goat or sheep births, are needed
Low Sensitivity of T-Cell Based Detection of Tuberculosis among HIV Co-Infected Tanzanian In-Patients
Objective: To evaluate the performance of QuantiFERON-TB GOLD (QFTG) in aĀ resource-poor setting among patients with and without HIV infection.Design: Cross-sectional study.Setting: Two hospitals in Northern Tanzania.Subjects: Eighty three adult male and female inpatients.Intervention: All patients were screened for HIV infection and underwent tuberculinĀ skin test (TST) and QFTG.Results: Eighty-three subjects were enrolled, and 29 (35%) of 83 were HIV-infected.Ā QFTG yielded indeterminate results in 12 (22%; 95%CI 12%-34%) of 54 HIV-uninfectedĀ and 13 (45%; 95%CI 26%-64%) of 29 HIV-infected subjects (p=0.0323). Among thoseĀ with smear-positive pulmonary tuberculosis, TST was positive in 40 (100%; 95%CIĀ 91%-100%) of 40 HIV-uninfected subjects compared with seven (54%; 95%CI 25%-Ā 81%) of 13 HIV-infected subjects (p<0.0001), and QFTG was positive in 28(70%; 95%CIĀ 53%-83%) of 40 HIV-uninfected subjects compared with three (23%; 95%CI 5%-54%)Ā of 13 HIV-infected subjects (p=0.0029). Among medical inpatients at risk for latentĀ tuberculosis infection, TST was positive in seven (50%) of 14 HIV-uninfected patientsĀ and three (19%) of 16 HIV-infected patients (p=0.0701) and QFTG was positive amongĀ two (14%) of 14 HIV-uninfected patients and three (19%) of 16 HIV-infected patientsĀ (p=0.7437).Conclusions: The presence of HIV co-infection was associated with a significant reductionĀ in sensitivity of both the TST (p<0.0001) and QFTG (p=0.0029) for the diagnosis ofĀ active M.tuberculosis infection. The high proportion of indeterminate QFTG and lackĀ of sensitivity, particularly among HIV-infected patients, may limit its applicability inĀ settings like Tanzania. Larger studies in resource-poor settings are required.
Whole-genome sequencing for One Health surveillance of antimicrobial resistance in conflict zones: a case study of Salmonella spp. and Campylobacter spp. in the West Bank, Palestine
Antimicrobial resistance (AMR) is a critical global concern driven by the overuse, misuse, and/or usage of inadequate antibiotics on humans, animals' agriculture, and as a result of contaminated environments. This study is the first One Health survey in the Middle East that incorporated whole-genome sequencing (WGS) to examine the spread of AMR in Campylobacter spp. and Salmonella spp. This cross-sectional study was conducted to examine the role of AMR at the human-animal-environmental interface and was performed in Ramallah/Al-Bireh and Jerusalem governorates of the central West Bank, Palestine. In 2021 and 2022, a total of 592 samples were collected and analyzed. From a total of 65 Campylobacter jejuni and 19 Salmonella spp. isolates, DNA was extracted for WGS using Oxford Nanopore Technologies MinION platform. We found that the dominant serotypes of C. jejuni and Salmonella enterica were present in chicken manure, chicken meat sold in markets, and feces of asymptomatic farm workers, with high genetic similarities between the isolates regardless of origin. Additionally, our results showed rapid strain turnover in C. jejuni from the same sites between 2021 and 2022. Most of the positive Salmonella spp. samples were multidrug-resistant (MDR) S. enterica serovar Muenchen carrying the plasmid of emerging S. infantis (pESI) megaplasmid, conferring resistance to multiple antibiotics. Our findings highlight the spread of MDR foodborne pathogens from animals to humans through the food chain, emphasizing the importance of a One Health approach that considers the interconnections between human, animal, and environmental health. IMPORTANCE Prior to this study, there existed hardly an integrated human-animal-environmental study of Salmonellosis and Campylobacteriosis and related AMR in Middle Eastern countries. The few existing studies lack robust epidemiological study designs, adequate for a One Health approach, and did not use WGS to determine the circulating serotypes and their AMR profiles. Civil unrest and war in Middle Eastern countries drive AMR because of the breakdown of public health and food security services. This study samples simultaneously humans, animals, and the environment to comprehensively investigate foodborne pathogens in the broiler chicken production chain in Palestine using WGS. We show that identical serotypes of C. jejuni and S. enterica can be found in samples from chicken farms, chicken meat sold in markets, and asymptomatic broiler chicken production workers. The most striking feature is the rapid dynamic of change in the genetic profile of the detected species in the same sampling locations. The majority of positive Salmonella spp. samples are MDR S. enterica serovar Muenchen isolates carrying the pESI megaplasmid. The results demonstrate a close relationship between the S. enterica serovar Muenchen isolates found in our sample collection and those responsible for 40% of all clinical Salmonella spp. isolates in Israel as previously reported, with a sequence identity of over 99.9%. These findings suggest the transboundary spread of MDR S. enterica serovar Muenchen strains from animals to humans through the food chain. The study underscores the importance of combining integrated One Health studies with WGS for detecting environmental-animal-human transmission of foodborne pathogens that could not be detected otherwise. This study showcases the benefits of integrated environmental-animal-human sampling and WGS for monitoring AMR. Environmental samples, which may be more accessible in conflict-torn places where monitoring systems are limited and regulations are weak, can provide an effective AMR surveillance solution. WGS of bacterial isolates provides causal inference of the distribution and spread of bacterial serotypes and AMR in complex social-ecological systems. Consequently, our results point toward the expected benefits of operationalizing a One Health approach through closer cooperation of public and animal health and food safety authorities
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