Aislamiento, identificación y actividad antimicrobiana de bacterias del ácido láctico del estuario de Bahía Blanca

This study analyzed the biodiversity of lactic acid bacteria present in the Bahía Blanca Estuary and their antimicrobial activity against pathogens associated with the cultivation of salmonid. A total of 21 lactic acid bacteria (LAB) strains were isolated from superficial sediments and fish of the estuary. The fish species were selected from those that spend most of their life cycle in the estuary. According to 16S rDNA analysis, isolates were affiliated with the genera Lactobacillus, Pediococcus, Leuconostoc, Enterococcus and Weissella. The predominant LAB isolates from the fish species belonged to Weissella viridescens, which was isolated from three of the four species analyzed. None of the LAB species isolated from fish was found in sediments. The agar diffusion method was used for detection of antagonistic activity against Listeria monocytogenes, Yersinia ruckeri, Aeromonas salmonicida subsp. salmonicida and two strains of Lactococcus garvieae. All the isolates exhibited some degree of antagonistic activity against L. monocytogenes, Y. ruckeri and both strains of Lc. garvieae. Twelve strains were found to be inhibitory for A. salmonicida. This study is the first report on the diversity of lactic acid bacteria in a coastal marine environment and fish from Argentina. The sediments and fish analyzed showed microbial strains with the ability to suppress pathogen growth under in vitro conditions, suggesting their potential as biological control agents for aquaculture and fish processing.Este estudio analiza la biodiversidad de bacterias del ácido láctico presentes en el estuario de Bahía Blanca y su actividad antimicrobiana frente a patógenos relacionados con el cultivo de salmónidos. Se aislaron 21 cepas de bacterias del ácido láctico a partir de peces y sedimentos del estuario. Las especies de peces fueron seleccionadas entre aquellas que habitan la mayor parte de su ciclo en el estuario. De acuerdo al análisis de la secuencia 16S ADNr, los aislamientos correspondieron a los géneros Lactobacillus, Pediococcus, Leuconostoc, Enterococcus y Weissella. La especie predominante en los aislamientos obtenidos de peces fue Weissella viridescens, la cual fue aislada de tres de las cuatro especies de peces estudiados. Ninguna de las especies aisladas de los peces fue encontrada en los sedimentos. El método de difusión en agar se empleó para detectar la actividad antimicrobiana de las cepas aisladas frente a patógenos de salmónidos: Yersinia ruckeri, Aeromonas salmonicida subsp. salmonicida, y dos cepas de Lactococcus garvieae, y frente a Listeria monocytogenes. Todas las cepas mostraron algún grado de inhibición frente a L. monocytogenes, Y. ruckeri and Lc. garvieae. Doce cepas mostraron actividad frente a A. salmonicida. Este estudio es el primer reporte sobre la diversidad de bacterias del ácido láctico en un ambiente marino costero y en peces de la Argentina. Las cepas de bacterias del ácido láctico obtenidas de peces y sedimentos con capacidad de inhibir in vitro los patógenos estudiados podrían tener aplicación en el control biológico en acuicultura y en la industria procesadora de pescado.Fil: Sica, María Gabriela. Universidad Nacional del Sur; ArgentinaFil: Olivera, Nelda Lila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Brugnoni, Lorena Inés. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Marucci, Patricia Liliana. Universidad Nacional del Sur; ArgentinaFil: López Cazorla, Andrea C.. Universidad Nacional del Sur; ArgentinaFil: Cubitto, María Amelia. Universidad Nacional del Sur; Argentin

Neonatal Astrocyte Damage Is Sufficient to Trigger Progressive Striatal Degeneration in a Rat Model of Glutaric Acidemia-I

BACKGROUND: We have investigated whether an acute metabolic damage to astrocytes during the neonatal period may critically disrupt subsequent brain development, leading to neurodevelopmental disorders. Astrocytes are vulnerable to glutaric acid (GA), a dicarboxylic acid that accumulates in millimolar concentrations in Glutaric Acidemia I (GA-I), an inherited neurometabolic childhood disease characterized by degeneration of striatal neurons. While GA induces astrocyte mitochondrial dysfunction, oxidative stress and subsequent increased proliferation, it is presently unknown whether such astrocytic dysfunction is sufficient to trigger striatal neuronal loss. METHODOLOGY/PRINCIPAL FINDINGS: A single intracerebroventricular dose of GA was administered to rat pups at postnatal day 0 (P0) to induce an acute, transient rise of GA levels in the central nervous system (CNS). GA administration potently elicited proliferation of astrocytes expressing S100β followed by GFAP astrocytosis and nitrotyrosine staining lasting until P45. Remarkably, GA did not induce acute neuronal loss assessed by FluoroJade C and NeuN cell count. Instead, neuronal death appeared several days after GA treatment and progressively increased until P45, suggesting a delayed onset of striatal degeneration. The axonal bundles perforating the striatum were disorganized following GA administration. In cell cultures, GA did not affect survival of either striatal astrocytes or neurons, even at high concentrations. However, astrocytes activated by a short exposure to GA caused neuronal death through the production of soluble factors. Iron porphyrin antioxidants prevented GA-induced astrocyte proliferation and striatal degeneration in vivo, as well as astrocyte-mediated neuronal loss in vitro. CONCLUSIONS/SIGNIFICANCE: Taken together, these results indicate that a transient metabolic insult with GA induces long lasting phenotypic changes in astrocytes that cause them to promote striatal neuronal death. Pharmacological protection of astrocytes with antioxidants during encephalopatic crisis may prevent astrocyte dysfunction and the ineluctable progression of disease in children with GA-I

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Improved imputation of low-frequency and rare variants using the UK10K haplotype reference panel

Imputing genotypes from reference panels created by whole-genome sequencing (WGS) provides a cost-effective strategy for augmenting the single-nucleotide polymorphism (SNP) content of genome-wide arrays. The UK10K Cohorts project has generated a data set of 3,781 whole genomes sequenced at low depth (average 7x), aiming to exhaustively characterize genetic variation down to 0.1% minor allele frequency in the British population. Here we demonstrate the value of this resource for improving imputation accuracy at rare and low-frequency variants in both a UK and an Italian population. We show that large increases in imputation accuracy can be achieved by re-phasing WGS reference panels after initial genotype calling. We also present a method for combining WGS panels to improve variant coverage and downstream imputation accuracy, which we illustrate by integrating 7,562 WGS haplotypes from the UK10K project with 2,184 haplotypes from the 1000 Genomes Project. Finally, we introduce a novel approximation that maintains speed without sacrificing imputation accuracy for rare variants

Whole-genome sequence-based analysis of thyroid function

Tiina Paunio on työryhmän UK10K Consortium jäsen.Normal thyroid function is essential for health, but its genetic architecture remains poorly understood. Here, for the heritable thyroid traits thyrotropin (TSH) and free thyroxine (FT4), we analyse whole-genome sequence data from the UK10K project (N = 2,287). Using additional whole-genome sequence and deeply imputed data sets, we report meta-analysis results for common variants (MAF >= 1%) associated with TSH and FT4 (N = 16,335). For TSH, we identify a novel variant in SYN2 (MAF = 23.5%, P = 6.15 x 10(-9)) and a new independent variant in PDE8B (MAF = 10.4%, P = 5.94 x 10(-14)). For FT4, we report a low-frequency variant near B4GALT6/ SLC25A52 (MAF = 3.2%, P = 1.27 x 10(-9)) tagging a rare TTR variant (MAF = 0.4%, P = 2.14 x 10(-11)). All common variants explain >= 20% of the variance in TSH and FT4. Analysis of rare variants (MAFPeer reviewe

Role of T cells during the cerebral infection with Trypanosoma brucei

The infection by Trypanosoma brucei brucei (T.b.b.), a protozoan parasite, is characterized by an early-systemic stage followed by a late stage in which parasites invade the brain parenchyma in a T cell-dependent manner. Here we found that early after infection effector-memory T cells were predominant among brain T cells, whereas, during the encephalitic stage T cells acquired a tissue resident memory phenotype (TRM) and expressed PD1. Both CD4 and CD8 T cells were independently redundant for the penetration of T.b.b. and other leukocytes into the brain parenchyma. The role of lymphoid cells during the T.b.b. infection was studied by comparing T- and B-cell deficient rag1-/- and WT mice. Early after infection, parasites located in circumventricular organs, brain structures with increased vascular permeability, particularly in the median eminence (ME), paced closed to the sleep-wake regulatory arcuate nucleus of the hypothalamus (Arc). Whereas parasite levels in the ME were higher in rag1-/- than in WT mice, leukocytes were instead reduced. Rag1-/- infected mice showed increased levels of meca32 mRNA coding for a blood /hypothalamus endothelial molecule absent in the blood-brain-barrier (BBB). Both immune and metabolic transcripts were elevated in the ME/Arc of WT and rag1-/- mice early after infection, except for ifng mRNA, which levels were only increased in WT mice. Finally, using a non-invasive sleep-wake cycle assessment method we proposed a putative role of lymphocytes in mediating sleep alterations during the infection with T.b.b. Thus, the majority of T cells in the brain during the early stage of T.b.b. infection expressed an effector-memory phenotype while TRM cells developed in the late stage of infection. T cells and parasites invade the ME/Arc altering the metabolic and inflammatory responses during the early stage of infection and modulating sleep disturbances

iNOS is expressed by perivascular macrophages in the brain during infection with <i>T</i>.<i>b</i>. <i>brucei</i>.

<p>(A) Concentration of NO₃ in plasma as measured by Griess assay after nitrate reductase reaction. The mean NO₃ concentration ± SEM in the plasma of infected mice (n = 5 per time point) is depicted. Differences with uninfected controls are significant (**p<0.01, ***p<0.001, unpaired Student’s <i>t</i> test). (B) Levels of S-nitrosylated molecules in plasma as measured using the 2,3-diaminonapthalene (DAN) assay. The mean relative fluorescence units (RFU) ± SEM in WT and <i>inos</i>^<i>-/-</i> infected and control animals are indicated. Differences with uninfected control and <i>inos</i>^<i>-/—</i>infected mice are significant (**<i>p</i><0.01, unpaired Student’s t test). (C) The accumulation of <i>inos</i> or <i>hprt</i> transcripts in brains sampled at various dpi with <i>T</i>.<i>b</i>. <i>brucei</i> was measured by real time PCR. The mean fold <i>inos</i> mRNA increase ± SEM in brains from infected mice (n ≥ 5 per group) is depicted. Differences with controls are significant (*<i>p</i><0.05; ***<i>p</i><0.001, unpaired Student’s <i>t</i> test). (D) Levels of S-nitrosylated proteins in brain lysates from <i>T</i>.<i>b</i>. <i>brucei</i> infected mice were measured by the biotin switch assay as described in the supplemental methods (<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005442#ppat.1005442.s011" target="_blank">S1 Text</a>). GAPDH was used as a loading control. Similar results were obtained in 3 independent experiments. (E) iNOS labelling in the brain of WT mice at 0 or 30 dpi with <i>T</i>.<i>b</i>. <i>brucei</i>. (F) Immunolabelling with the activated microglia marker Iba-1 in a WT mouse. (G) FACS analysis of CD45^highCD11b⁺ macrophages (R1), CD45^dim CD11b⁺ microglia (R2) and CD45^high CD11b^- lymphocytes (R3) in the brain of WT mice was determined at 0 or 25 dpi. (H) The frequency of iNOS⁺ cells in gated populations (panel G) are depicted. Cells from <i>inos</i>^<i>-/-</i> infected mice were used as negative controls. (I) The mean percentage ± SEM of iNOS⁺ CD45^high CD11b⁺ or CD45^dim CD11b⁺ (n = 4 per group) is depicted. (J) Levels of <i>inos</i> transcripts in sorted CD45^highCD11b⁺, CD45^dimCD11b⁺ and CD45^high CD11b^- populations are shown. Three mice were pooled for each determination and at least 4 independent determinations were performed.</p

iNOS expression is associated with integrity of the BBB during infection with <i>T</i>.<i>b</i>. <i>brucei</i>.

<p>(A, D, F) IgG (A) and fibrin (D) immunolabeling and Evan’s blue extravasation (F) in the brains of WT and <i>inos</i>^<i>-/-</i> mice 23 dpi with <i>T</i>.<i>b</i>. <i>brucei</i>. (B, E, G) The mean relative integrated fluorescence densities (RIF) of IgG (B), fibrin (E) or EB (G) ± SEM in the brain parenchyma from at least 3 sections per brain and 4 animals per group are depicted. (C) IgG was also detected by Western Blot in brain lysates of <i>inos</i>^<i>-/-</i> mice 25 dpi with <i>T</i>.<i>b</i>. <i>brucei</i> but not in infected or uninfected WT mice. Differences between WT and <i>inos</i>^<i>-/-</i> mice are significant (*<i>p</i><0.05 unpaired Student’s <i>t</i> test).</p