943 research outputs found

    Variation in genome content and predatory phenotypes between \u3cem\u3eBdellovibrio\u3c/em\u3e sp. NC01 isolated from soil and \u3cem\u3eB. bacteriovorus\u3c/em\u3e type strain HD100

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    Defining phenotypic and associated genotypic variation among Bdellovibrio may further our understanding of how this genus attacks and kills different Gram-negative bacteria. We isolated Bdellovibrio sp. NC01 from soil. Analysis of 16S rRNA gene sequences and average amino acid identity showed that NC01 belongs to a different species than the type species bacteriovorus. By clustering amino acid sequences from completely sequenced Bdellovibrio and comparing the resulting orthologue groups to a previously published analysis, we defined a ‘core genome’ of 778 protein-coding genes and identified four protein-coding genes that appeared to be missing only in NC01. To determine how horizontal gene transfer (HGT) may have impacted NC01 genome evolution, we performed genome-wide comparisons of Bdellovibrio nucleotide sequences, which indicated that eight NC01 genomic regions were likely acquired by HGT. To investigate how genome variation may impact predation, we compared protein-coding gene content between NC01 and the B. bacteriovorus type strain HD100, focusing on genes implicated as important in successful killing of prey. Of these, NC01 is missing ten genes that may play roles in lytic activity during predation. Compared to HD100, NC01 kills fewer tested prey strains and kills Escherichia coli ML35 less efficiently. NC01 causes a smaller log reduction in ML35, after which the prey population recovers and the NC01 population decreases. In addition, NC01 forms turbid plaques on lawns of E. coli ML35, in contrast to clear plaques formed by HD100. Linking phenotypic variation in interactions between Bdellovibrio and Gram-negative bacteria with underlying Bdellovibrio genome variation is valuable for understanding the ecological significance of predatory bacteria and evaluating their effectiveness in clinical applications

    Variation in genome content and predatory phenotypes between Bdellovibrio sp. NC01 isolated from soil and B. bacteriovorus type strain HD100

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    © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Williams, L. E., Cullen, N., DeGiorgis, J. A., Martinez, K. J., Mellone, J., Oser, M., Wang, J., & Zhang, Y. Variation in genome content and predatory phenotypes between Bdellovibrio sp. NC01 isolated from soil and B. bacteriovorus type strain HD100. Microbiology, 165(12), (2019): 1315-1330, doi: 10.1099/mic.0.000861.Defining phenotypic and associated genotypic variation among Bdellovibrio may further our understanding of how this genus attacks and kills different Gram-negative bacteria. We isolated Bdellovibrio sp. NC01 from soil. Analysis of 16S rRNA gene sequences and average amino acid identity showed that NC01 belongs to a different species than the type species bacteriovorus. By clustering amino acid sequences from completely sequenced Bdellovibrio and comparing the resulting orthologue groups to a previously published analysis, we defined a ‘core genome’ of 778 protein-coding genes and identified four protein-coding genes that appeared to be missing only in NC01. To determine how horizontal gene transfer (HGT) may have impacted NC01 genome evolution, we performed genome-wide comparisons of Bdellovibrio nucleotide sequences, which indicated that eight NC01 genomic regions were likely acquired by HGT. To investigate how genome variation may impact predation, we compared protein-coding gene content between NC01 and the B. bacteriovorus type strain HD100, focusing on genes implicated as important in successful killing of prey. Of these, NC01 is missing ten genes that may play roles in lytic activity during predation. Compared to HD100, NC01 kills fewer tested prey strains and kills Escherichia coli ML35 less efficiently. NC01 causes a smaller log reduction in ML35, after which the prey population recovers and the NC01 population decreases. In addition, NC01 forms turbid plaques on lawns of E. coli ML35, in contrast to clear plaques formed by HD100. Linking phenotypic variation in interactions between Bdellovibrio and Gram-negative bacteria with underlying Bdellovibrio genome variation is valuable for understanding the ecological significance of predatory bacteria and evaluating their effectiveness in clinical applications.This research was supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant no. P20GM103430 and by funding to LEW from Providence College. This material is based upon work conducted at a Rhode Island NSF EPSCoR research facility, the Genomics and Sequencing Center, supported in part by the National Science Foundation EPSCoR Cooperative Agreement #EPS-1004057. This material is based upon work supported in part by the National Science Foundation under EPSCoR Cooperative Agreement #OIA-1655221. The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication

    Association between the histopathologic findings of a zero-time biopsy and the donor kidney function 24 hours and a year after nephrectomy

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    Background: The living-donor transplantation (LDT) is essential to provide patients with chronic kidney disease (CKD) a superior quality of life and improve their lifespan. Recent investigations prove that the living donors (LD) have a risk of developing CKD, without there being a way to anticipate it. The zero-time biopsies provide valuable information that may contribute to this objective since they report histopathologic findings of subclinical chronic damage. Methods: Retrospective, observational and analytical study. The information from the medical files and pathology department of LD attended at “Dr. Miguel Silva” general hospital from January 2006 to January 2018 was analyzed. The glomerular filtrate rate was obtained 24 hours and a year after nephrectomy and was estimated based on CDK-EPI. The comparison among groups was made through Mann-Whitney testing for continuous numeric. A value of p36 years, the dropping of the GFR >43%, the GFR and the creatinine levels after 24 hours of nephrectomy were associated with a reduction of the GFR the year after nephrectomy

    LIGO detector characterization in the second and third observing runs

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    The characterization of the Advanced LIGO detectors in the second and third observing runs has increased the sensitivity of the instruments, allowing for a higher number of detectable gravitational-wave signals, and provided confirmation of all observed gravitational-wave events. In this work, we present the methods used to characterize the LIGO detectors and curate the publicly available datasets, including the LIGO strain data and data quality products. We describe the essential role of these datasets in LIGO–Virgo Collaboration analyses of gravitational-waves from both transient and persistent sources and include details on the provenance of these datasets in order to support analyses of LIGO data by the broader community. Finally, we explain anticipated changes in the role of detector characterization and current efforts to prepare for the high rate of gravitational-wave alerts and events in future observing runs

    Reconstructing the Population Genetic History of the Caribbean

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    The Caribbean basin is home to some of the most complex interactions in recent history among previously diverged human populations. Here, by making use of genome-wide SNP array data, we characterize ancestral components of Caribbean populations on a sub-continental level and unveil fine-scale patterns of population structure distinguishing insular from mainland Caribbean populations as well as from other Hispanic/Latino groups. We provide genetic evidence for an inland South American origin of the Native American component in island populations and for extensive pre-Columbian gene flow across the Caribbean basin. The Caribbean-derived European component shows significant differentiation from parental Iberian populations, presumably as a result of founder effects during the colonization of the New World. Based on demographic models, we reconstruct the complex population history of the Caribbean since the onset of continental admixture. We find that insular populations are best modeled as mixtures absorbing two pulses of African migrants, coinciding with early and maximum activity stages of the transatlantic slave trade. These two pulses appear to have originated in different regions within West Africa, imprinting two distinguishable signatures in present day Afro-Caribbean genomes and shedding light on the genetic impact of the dynamics occurring during the slave trade in the Caribbean.Comment: 26 pages, 6 figures, and supporting informatio

    Extracorporeal liver assist device to exchange albumin and remove endotoxin in acute liver failure: Results of a pivotal pre-clinical study

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    Background & AimsIn acute liver failure, severity of liver injury and clinical progression of disease are in part consequent upon activation of the innate immune system. Endotoxaemia contributes to innate immune system activation and the detoxifying function of albumin, critical to recovery from liver injury, is irreversibly destroyed in acute liver failure. University College London-Liver Dialysis Device is a novel artificial extracorporeal liver assist device, which is used with albumin infusion, to achieve removal and replacement of dysfunctional albumin and reduction in endotoxaemia. We aimed to test the effect of this device on survival in a pig model of acetaminophen-induced acute liver failure.MethodsPigs were randomised to three groups: Acetaminophen plus University College London-Liver Dialysis Device (n=9); Acetaminophen plus Control Device (n=7); and Control plus Control Device (n=4). Device treatment was initiated two h after onset of irreversible acute liver failure.ResultsThe Liver Dialysis Device resulted in 67% reduced risk of death in acetaminophen-induced acute liver failure compared to Control Device (hazard ratio=0.33, p=0.0439). This was associated with 27% decrease in circulating irreversibly oxidised human non-mercaptalbumin-2 throughout treatment (p=0.046); 54% reduction in overall severity of endotoxaemia (p=0.024); delay in development of vasoplegia and acute lung injury; and delay in systemic activation of the TLR4 signalling pathway. Liver Dialysis Device-associated adverse clinical effects were not seen.ConclusionsThe survival benefit and lack of adverse effects would support clinical trials of University College London-Liver Dialysis Device in acute liver failure patients

    Effects of Estradiol Withdrawal on Mood in Women With Past Perimenopausal Depression: A Randomized Clinical Trial

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    IMPORTANCE: Perimenopause is accompanied by an increased risk of new and recurrent depression. The coincidence of declining ovarian function with the onset of depression led to the inference that "withdrawal" from physiologic estradiol levels underpinned depression in perimenopause. To our knowledge, this is the first controlled systematic study to directly test the estrogen withdrawal theory of perimenopausal depression (PMD). OBJECTIVE: To examine the role of estradiol withdrawal in PMD. DESIGN, SETTING, AND PARTICIPANTS: Initial open-label treatment with estradiol followed by randomized, double-blind, placebo-controlled, parallel-design evaluation of continued estradiol treatment was evaluated at an outpatient research facility at the National Institutes of Health Clinical Center. An intent-to-treat analysis was performed between October 2003 and July 2012. Participants included asymptomatic postmenopausal women with past PMD responsive to hormone therapy (n = 26) and asymptomatic postmenopausal women with no history of depression (n = 30) matched for age, body mass index, and reproductive status who served as controls. Data were analyzed between November 2012 and October 2013 by repeated-measures analysis of variance. INTERVENTIONS: After 3 weeks of open-label administration of transdermal estradiol (100 µg/d), participants were randomized to a parallel design to receive either estradiol (100 µg/d; 27 participants) or matched placebo skin patches (29 participants) for 3 additional weeks under double-blind conditions. MAIN OUTCOMES AND MEASURES: Center for Epidemiologic Studies-Depression Scale and 17-item Hamilton Depression Rating Scale (completed by raters blind to diagnosis and randomization status), self-administered visual analog symptom ratings, and blood hormone levels obtained at weekly clinic visits. RESULTS: None of the women reported depressive symptoms during open-label use of estradiol. Women with past PMD who were crossed over from estradiol to placebo experienced a significant increase in depression symptom severity demonstrated using the Center for Epidemiologic Studies-Depression Scale and 17-item Hamilton Depression Rating Scale, with mean (SD) scores increasing from estradiol (ie, 2.4 [2.0] and 3.0 [2.5]) to placebo (8.8 [4.9] and 6.6 [4.5], respectively [P = .0004 for both]). Women with past PMD who continued estradiol therapy and all women in the control group remained asymptomatic. Women in both groups had similar hot-flush severity and plasma estradiol levels during use of placebo. CONCLUSIONS AND RELEVANCE: In women with past PMD that was previously responsive to hormone therapy, the recurrence of depressive symptoms during blinded hormone withdrawal suggests that normal changes in ovarian estradiol secretion can trigger an abnormal behavioral state in these susceptible women. Women with a history of PMD should be alert to the risk of recurrent depression when discontinuing hormone therapy. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00060736

    The \u3cem\u3eChlamydomonas\u3c/em\u3e Genome Reveals the Evolution of Key Animal and Plant Functions

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    Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the ∼120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella
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