Identification of Novel Mt-Guab2 Inhibitor Series Active against M. tuberculosis

Tuberculosis (TB) remains a leading cause of mortality worldwide. With the emergence of multidrug resistant TB, extensively drug resistant TB and HIV-associated TB it is imperative that new drug targets be identified. The potential of Mycobacterium tuberculosis inosine monophosphate dehydrogenase (IMPDH) as a novel drug target was explored in the present study. IMPDH exclusively catalyzes the conversion of inosine monophosphate (IMP) to xanthosine monophosphate (XMP) in the presence of the cofactor nicotinamide adenine dinucleotide (NAD+). Although the enzyme is a dehydrogenase, the enzyme does not catalyze the reverse reaction i.e. the conversion of XMP to IMP. Unlike other bacteria, M. tuberculosis harbors three IMPDH-like genes, designated as Mt-guaB1, Mt-guaB2 and Mt-guaB3 respectively. Of the three putative IMPDH's, we previously confirmed that Mt-GuaB2 was the only functional ortholog by characterizing the enzyme kinetically. Using an in silico approach based on designed scaffolds, a series of novel classes of inhibitors was identified. The inhibitors possess good activity against M. tuberculosis with MIC values in the range of 0.4 to 11.4 µg mL−1. Among the identified ligands, two inhibitors have nanomolar Kis against the Mt-GuaB2 enzyme

Recombinase technology: applications and possibilities

The use of recombinases for genomic engineering is no longer a new technology. In fact, this technology has entered its third decade since the initial discovery that recombinases function in heterologous systems (Sauer in Mol Cell Biol 7(6):2087–2096, 1987). The random insertion of a transgene into a plant genome by traditional methods generates unpredictable expression patterns. This feature of transgenesis makes screening for functional lines with predictable expression labor intensive and time consuming. Furthermore, an antibiotic resistance gene is often left in the final product and the potential escape of such resistance markers into the environment and their potential consumption raises consumer concern. The use of site-specific recombination technology in plant genome manipulation has been demonstrated to effectively resolve complex transgene insertions to single copy, remove unwanted DNA, and precisely insert DNA into known genomic target sites. Recombinases have also been demonstrated capable of site-specific recombination within non-nuclear targets, such as the plastid genome of tobacco. Here, we review multiple uses of site-specific recombination and their application toward plant genomic engineering. We also provide alternative strategies for the combined use of multiple site-specific recombinase systems for genome engineering to precisely insert transgenes into a pre-determined locus, and removal of unwanted selectable marker genes

Lessons from mouse chimaera experiments with a reiterated transgene marker:revised marker criteria and a review of chimaera markers

Recent reports of a new generation of ubiquitous transgenic chimaera markers prompted us to consider the criteria used to evaluate new chimaera markers and develop more objective assessment methods. To investigate this experimentally we used several series of fetal and adult chimaeras, carrying an older, multi-copy transgenic marker. We used two additional independent markers and objective, quantitative criteria for cell selection and cell mixing to investigate quantitative and spatial aspects of developmental neutrality. We also suggest how the quantitative analysis we used could be simplified for future use with other markers. As a result, we recommend a five-step procedure for investigators to evaluate new chimaera markers based partly on criteria proposed previously but with a greater emphasis on examining the developmental neutrality of prospective new markers. These five steps comprise (1) review of published information, (2) evaluation of marker detection, (3) genetic crosses to check for effects on viability and growth, (4) comparisons of chimaeras with and without the marker and (5) analysis of chimaeras with both cell populations labelled. Finally, we review a number of different chimaera markers and evaluate them using the extended set of criteria. These comparisons indicate that, although the new generation of ubiquitous fluorescent markers are the best of those currently available and fulfil most of the criteria required of a chimaera marker, further work is required to determine whether they are developmentally neutral. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11248-015-9883-7) contains supplementary material, which is available to authorized users

Investigation of hospital discharge cases and SARS-CoV-2 introduction into Lothian care homes

Background The first epidemic wave of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in Scotland resulted in high case numbers and mortality in care homes. In Lothian, over one-third of care homes reported an outbreak, while there was limited testing of hospital patients discharged to care homes. Aim To investigate patients discharged from hospitals as a source of SARS-CoV-2 introduction into care homes during the first epidemic wave. Methods A clinical review was performed for all patients discharges from hospitals to care homes from 1st March 2020 to 31st May 2020. Episodes were ruled out based on coronavirus disease 2019 (COVID-19) test history, clinical assessment at discharge, whole-genome sequencing (WGS) data and an infectious period of 14 days. Clinical samples were processed for WGS, and consensus genomes generated were used for analysis using Cluster Investigation and Virus Epidemiological Tool software. Patient timelines were obtained using electronic hospital records. Findings In total, 787 patients discharged from hospitals to care homes were identified. Of these, 776 (99%) were ruled out for subsequent introduction of SARS-CoV-2 into care homes. However, for 10 episodes, the results were inconclusive as there was low genomic diversity in consensus genomes or no sequencing data were available. Only one discharge episode had a genomic, time and location link to positive cases during hospital admission, leading to 10 positive cases in their care home. Conclusion The majority of patients discharged from hospitals were ruled out for introduction of SARS-CoV-2 into care homes, highlighting the importance of screening all new admissions when faced with a novel emerging virus and no available vaccine

Multimodal decoding of human liver regeneration.

Acknowledgements: This work was supported by a Wellcome Trust Senior Research Fellowship in Clinical Science (ref. 219542/Z/19/Z) to N.C.H., a Chan Zuckerberg Initiative Seed Network Grant to N.C.H., and a Tenovus Scotland grant (E20-03) to K.P.M., S. J. Wallace and N.C.H. J.R.P. was supported by a Medical Research Council Precision Medicine PhD studentship. C.A.K. was a cross-disciplinary post-doctoral fellow (XDF) supported by funding from the University of Edinburgh and Medical Research Council (MC_UU_00009/2). T.G.B. was funded by the Wellcome Trust (ref. WT107492Z). S.M. was funded by Cancer Research UK core funding to the CRUK Beatson Institute (refs. A17196 and A31287). J.B.G.M. was supported by a CRUK programme grant (A23390). F.F., J.B.G.M. and L.M.C. were supported by CRUK core funding to the Beatson Institute (A31287) and CRUK core funding to L.M.C. (A23983; DRCRPG-Nov22/100007). D.J.M. was supported by a Medical Research Council Senior Clinical Fellowship (MR/P008887/1). P.R. was supported by a Medical Research Council Clinician Scientist Fellowship (MR/N008340/1) and Medical Research Council Senior Clinical Fellowship (MR/W015919/1). M.M.S. was supported by a Peter Samuel Fellowship. We thank the patients who donated liver tissue for this study; J. Davidson, J. Black, C. Ibbotson and A. Baird of the Scottish Liver Transplant Unit and the research nurses of the Wellcome Trust Clinical Research Facility for assistance with consenting patients for this study; the liver transplant coordinators and surgeons of the Scottish Liver Transplant Unit and the surgeons and staff of the Hepatobiliary Surgical Unit, Royal Infirmary of Edinburgh for assistance in procuring human liver samples; the US ALFSG network for assistance in procuring human liver samples; core facilities and services at the Beatson Institute, in particular the Biological Research Unit & the Beatson Advanced Imaging Resource (BAIR); G. Jacquemet for advice on Cellpose segmentation for IVM analysis; R. Insall and L. Machesky for helpful scientific discussions; W. Mungall for technical support; C. Nicol for help with manuscript illustrations; N. Pham for technical assistance with Incucyte; and C. Winchester and R. Li for critical reading of the manuscript. We acknowledge the contribution to this study made by the University of Birmingham’s Human Biomaterials Resource Centre, which has been supported through Birmingham Science City–Experimental Medicine Network of Excellence project. This research was funded in whole, or in part, by the Wellcome Trust (Wellcome Trust Senior Research Fellowship in Clinical Science to N.C.H.; ref. 219542/Z/19/Z). This publication is part of the Human Cell Atlas (www.humancellatlas.org/publications).The liver has a unique ability to regenerate1,2; however, in the setting of acute liver failure (ALF), this regenerative capacity is often overwhelmed, leaving emergency liver transplantation as the only curative option3-5. Here, to advance understanding of human liver regeneration, we use paired single-nucleus RNA sequencing combined with spatial profiling of healthy and ALF explant human livers to generate a single-cell, pan-lineage atlas of human liver regeneration. We uncover a novel ANXA2+ migratory hepatocyte subpopulation, which emerges during human liver regeneration, and a corollary subpopulation in a mouse model of acetaminophen (APAP)-induced liver regeneration. Interrogation of necrotic wound closure and hepatocyte proliferation across multiple timepoints following APAP-induced liver injury in mice demonstrates that wound closure precedes hepatocyte proliferation. Four-dimensional intravital imaging of APAP-induced mouse liver injury identifies motile hepatocytes at the edge of the necrotic area, enabling collective migration of the hepatocyte sheet to effect wound closure. Depletion of hepatocyte ANXA2 reduces hepatocyte growth factor-induced human and mouse hepatocyte migration in vitro, and abrogates necrotic wound closure following APAP-induced mouse liver injury. Together, our work dissects unanticipated aspects of liver regeneration, demonstrating an uncoupling of wound closure and hepatocyte proliferation and uncovering a novel migratory hepatocyte subpopulation that mediates wound closure following liver injury. Therapies designed to promote rapid reconstitution of normal hepatic microarchitecture and reparation of the gut-liver barrier may advance new areas of therapeutic discovery in regenerative medicine

Características do zumbido em trabalhadores expostos a ruído The characteristics of tinnitus in workers exposed to noise

O zumbido é um sintoma auditivo relatado por indivíduos expostos ao ruído. OBJETIVO: Estudar as características do zumbido relatadas por indivíduos expostos ao ruído ocupacional. FORMA DE ESTUDO: Descritivo prospectivo. MATERIAL E MÉTODO: Participaram 52 indivíduos com idade média de 29 anos que faziam parte do programa de prevenção da perda auditiva de um frigorífico. Os indivíduos responderam a uma anamnese e suas audiometrias realizadas em 2005 e 2006 foram utilizadas. RESULTADOS: No presente estudo, 71% dos indivíduos apresentaram audiometria normal. A prevalência do zumbido para o sexo masculino foi de 16% e para o sexo feminino foi de 9% apresentando tempo médio de exposição ao ruído de sete anos a um nível médio de ruído entre 86 e 91 dBA (48%). Verificou-se um predomínio do zumbido bilateral (46%), do tipo chiado (40%) de intensidade média (49%), com tempo de instalação do sintoma entre um a cinco anos (67%), sendo sua freqüência semanal (41%) e a noite o período que mais perturba (34%). Encontrou-se significância entre a periodicidade do zumbido e o nível de ruído. CONCLUSÃO: Recomenda-se a inclusão do tema zumbido em programas de prevenção da perda auditiva a fim de promover a saúde auditiva dos trabalhadores.<br>Tinnitus is a common auditory complaint among individuals exposed to noise. AIM: this paper aims to study the characteristics of tinnitus in workers exposed to noise. STUDY DESIGN: this is a descriptive prospective study. MATERIALS AND METHOD: Fifty-two individuals averaging 29 years of age were enrolled in a hearing loss prevention program at a meat processing plant. The participants were interviewed and had their hearing tested in 2005 and 2006. RESULTS: seventy-one percent of the participants were found to have normal hearing. Tinnitus was present in 16% of the males and in 9% of the females. Mean noise exposure length was 7 years and noise levels ranged from 86 to 91 dBA (48%). Bilateral tinnitus (46%) of the hissing type (40%) and moderate intensity (49%) was the most prevalent. Symptoms began to be observed within one to five years after initial exposure to noise (67%) and manifested themselves in weekly episodes (41%) that bothered the patients mostly at night (34%). A significant correlation was observed between the frequency of tinnitus episodes and the noise levels to which workers were exposed. CONCLUSION: tinnitus should be included in hearing loss prevention programs in order to more comprehensively promote occupational hearing health