Search results for "microbiology"
showing 10 items of 7546 documents
The genus thiobacillus: Physiology and industrial applications
1983
This review deals with different aspects concerning the genus Thiobacillus as an obligat chemoautotroph able to oxidize reduced anorganic sulphur compounds. There are given the following topics: physiology of the genus (nutritional requirements, enzymatic complexes for sulphur oxidation, energy generation, reductive CO2 assimilation and growing in presence of organic compounds). The ecological significance of Thiobacilli in the sulphur cycle in Nature is presented. The industrial applications of Thiobacilli in respect to the leaching processes that allow the recovery of metals through oxidation and solubilization from low-grade ores are discussed, with special reference to copper and uraniu…
The fnr Gene of Bacillus licheniformis and the Cysteine Ligands of the C-Terminal FeS Cluster
1998
Many of the O2-responsive gene regulators of bacteria are members of the fumarate nitrate reductase-cyclic AMP receptor protein family of transcriptional regulators (12, 13, 15, 17) with predicted structures similar to those of the cyclic AMP receptor protein (11). The Fnr (stands for fumarate nitrate reductase regulator) protein from Escherichia coli (FnrEc) controls the expression of a variety of genes, mainly of anaerobic respiration and metabolism (5, 13). It contains a N-terminal cluster of three essential cysteine residues which are supposed to bind together with Cys122 a [4Fe 4S]2+ cluster which is required for O2 sensing (4, 7, 8, 10, 16). A wide variety of gram-negative bacteria co…
One pot light assisted green synthesis, storage and antimicrobial activity of dextran stabilized silver nanoparticles.
2014
Background Green synthesis of nanomaterials finds the edge over chemical methods due to its environmental compatibility. Herein, we report green synthesis of silver nanoparticles (Ag NPs) mediated with dextran. Dextran was used as a stabilizer and capping agent to synthesize Ag NPs using silver nitrate (AgNO3) under diffused sunlight conditions. Results UV–vis spectra of as synthesized Ag nanoparticles showed characteristic surface plasmon band in the range from ~405-452 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies showed spherical Ag NPs in the size regime of ~50-70 nm. Face centered cubic lattice of Ag NPs was confirmed by powder X-ray diffraction (PXRD…
Molecular basis of early epithelial response to streptococcal exotoxin: role of STIM1 and Orai1 proteins
2011
Streptolysin O (SLO) is a cholesterol-dependent cytolysin (CDC) from Streptococcus pyogenes. SLO induces diverse types of Ca(2+) signalling in host cells which play a key role in membrane repair and cell fate determination. The mechanisms behind SLO-induced Ca(2+) signalling remain poorly understood. Here, we show that in NCI-H441 cells, wild-type SLO as well as non-pore-forming mutant induces long-lasting intracellular Ca(2+) oscillations via IP(3) -mediated depletion of intracellular stores and activation of store-operated Ca(2+) (SOC) entry. SLO-induced activation of SOC entry was confirmed by Ca(2+) add-back experiments, pharmacologically and by overexpression as well as silencing of ST…
Evolutionary Study of Disorder in Protein Sequences
2020
Intrinsically disordered proteins (IDPs) contain regions lacking intrinsic globular structure (intrinsically disordered regions, IDRs). IDPs are present across the tree of life, with great variability of IDR type and frequency even between closely related taxa. To investigate the function of IDRs, we evaluated and compared the distribution of disorder content in 10,695 reference proteomes, confirming its high variability and finding certain correlation along the Euteleostomi (bony vertebrates) lineage to number of cell types. We used the comparison of orthologs to study the function of disorder related to increase in cell types, observing that multiple interacting subunits of protein comple…
Ventilator-Associated Pneumonia in Patients with COVID-19: A Systematic Review and Meta-Analysis
2021
The aim of this systematic review and meta-analysis was to estimate the pooled occurrence of ventilator-associated pneumonia (VAP) among patients admitted to an intensive care unit with COVID-19 and mortality of those who developed VAP. We performed a systematic search on PubMed, EMBASE and Web of Science from inception to 2nd March 2021 for nonrandomized studies specifically addressing VAP in adult patients with COVID-19 and reporting data on at least one primary outcome of interest. Random effect single-arm meta-analysis was performed for the occurrence of VAP and mortality (at the longest follow up) and ICU length of stay. Twenty studies were included in the systematic review and meta-an…
Distinctive Evasion Mechanisms to Allow Persistence of Borrelia burgdorferi in Different Human Cell Lines
2021
Lyme borreliosis is a multisystemic disease caused by the pleomorphic bacteria of the Borrelia burgdorferi sensu lato complex. The exact mechanisms for the infection to progress into a prolonged sequelae of the disease are currently unknown, although immune evasion and persistence of the bacteria in the host are thought to be major contributors. The current study investigated B. burgdorferi infection processes in two human cell lines, both non-immune and non-phagocytic, to further understand the mechanisms of infection of this bacterium. By utilizing light, confocal, helium ion, and transmission electron microscopy, borrelial infection of chondrosarcoma (SW1353) and dermal fibroblast (BJ) c…
Autour de L’écriture des juristes. Sur la question de l’action de l’écriture et du droit
2014
Resume : Cet article entre dans le champ "Droit et litterature" a partir de la question de l'action, qui n'est ici ni la notion des sociologues, ni celle de la rhetorique. Reflechir en termes d'action d'ecriture ou d'action de l'ecrit permet de deplacer les appartenances disciplinaires, comme le montrent plusieurs cas envisages dans un ouvrage collectif consacre a L'ecriture des juristes (Garnier, 2010). Ce "retour sur experience" est ainsi l'occasion de poser plusieurs questions : comment le droit agit-il ? quel est le rapport entre une volonte (royale par exemple) et une action d'ecriture mise en œuvre par toutes sortes de personnes, sur la longue duree ? comment l'ecrit participe-t-il d'…
Interkingdom Gut Microbiome and Resistome of the Cockroach Blattella germanica
2021
Cockroaches are intriguing animals with two coexisting symbiotic systems, an endosymbiont in the fat body, involved in nitrogen metabolism, and a gut microbiome whose diversity, complexity, role, and developmental dynamics have not been fully elucidated. In this work, we present a metagenomic approach to study Blattella germanica populations not treated, treated with kanamycin, and recovered after treatment, both naturally and by adding feces to the diet, with the aim of better understanding the structure and function of its gut microbiome along the development as well as the characterization of its resistome.
Crystallization and preliminary crystallographic analysis of the major capsid proteins VP16 and VP17 of bacteriophage P23-77.
2012
The major capsid proteins VP16 and VP17 of bacteriophage P23-77 have been crystallized using both recombinant and purified virus and preliminary diffraction analyses have been performed.