Search results for "Bacterium"
showing 10 items of 595 documents
Transcriptome analysis revealed that a quorum sensing system regulates the transfer of the pAt megaplasmid in Agrobacterium tumefaciens.
2016
Background Agrobacterium tumefaciens strain P4 is atypical, as the strain is not pathogenic and produces a for this species unusual quorum sensing signal, identified as N-(3-hydroxy-octanoyl)-homoserine lactone (3OH,C8-HSL). Results By sequence analysis and cloning, a functional luxI-like gene, named cinI, has been identified on the At plasmid of A. tumefaciens strain P4. Insertion mutagenesis in the cinI gene and transcriptome analyses permitted the identification of 32 cinI-regulated genes in this strain, most of them encoding proteins responsible for the conjugative transfer of pAtP4. Among these genes were the avhB genes that encode a type 4 secretion system (T4SS) involved in the forma…
The Impact of Microbiota on the Pathogenesis of Amyotrophic Lateral Sclerosis and the Possible Benefits of Polyphenols. An Overview
2021
The relationship between gut microbiota and neurodegenerative diseases is becoming clearer. Among said diseases amyotrophic lateral sclerosis (ALS) stands out due to its severity and, as with other chronic pathologies that cause neurodegeneration, gut microbiota could play a fundamental role in its pathogenesis. Therefore, polyphenols could be a therapeutic alternative due to their anti-inflammatory action and probiotic effect. Thus, the objective of our narrative review was to identify those bacteria that could have connection with the mentioned disease (ALS) and to analyze the benefits produced by administering polyphenols. Therefore, an extensive search was carried out selecting the most…
Extending the hosts of Tectiviridae into four additional genera of Gram-positive bacteria and more diverse Bacillus species
2017
Abstract Tectiviridae are composed of tailless bacteriophages with an icosahedral capsid and an inner membrane enclosing a double-stranded 15 kb linear DNA genome. Five of the seven previously studied Tectivirus isolates infect bacteria from Bacillus cereus sensu lato group (Betatectivirus), one distantly related member (PRD1) infect Enterobactericeae (Alpatectivirus) and one recently discovered virus infect Gluconobacter cerinus (Gammatectivirus). Here we expand the host spectrum of Betatectivirus elements to four additional genera (Streptococcus, Exiguobacterium, Clostridium and Brevibacillus) and to more distantly related Bacillus species (B. pumilus and B. flexus) by studying the genome…
ICTV Virus Taxonomy Profile: Finnlakeviridae
2020
Finnlakeviridae is a family of icosahedral, internal membrane-containing bacterial viruses with circular, single-stranded DNA genomes. The family includes the genus, Finnlakevirus, with the species, Flavobacterium virus FLiP. Flavobacterium phage FLiP was isolated with its Gram-negative host bacterium from a boreal freshwater habitat in Central Finland in 2010. It is the first described single-stranded DNA virus with an internal membrane and shares minimal sequence similarity with other known viruses. The virion organization (pseudo T=21 dextro) and major capsid protein fold (double-β-barrel) resemble those of Pseudoalteromonas phage PM2 (family Corticoviridae), which has a double-stranded…
Biosurfactant production by hydrocarbon-degradingBrevibacteriumandVibrioisolates from the sea penPteroeides spinosum(Ellis, 1764)
2016
Among filter-feeders, pennatulids are the most complex and polymorphic members of the cnidarian class Anthozoa. They display a wide distribution throughout all the oceans, constituting a significant component of the sessile megafauna from intertidal to abyssal depths. In this study, a total of 118 bacterial isolates from enrichment cultures, carried out with homogenates of the sea pen Pteroeides spinosum (Ellis, 1764), were screened for hydrocarbon utilization by using the 2,6-dichlorophenol indophenol assay. Among them, 83 hydrocarbon-oxidizing isolates were analyzed for biosurfactant production by standard screening tests (i.e., emulsifying activity, E24 detection, surface tension measure…
Lactic Acid Bacteria
2008
A typical lactic acid bacterium grown under standard conditions is aerotolerant, acid tolerant, organotrophic, and a strictly fermentative rod or coccus, producing lactic acid as a major end product. It lacks cytochromes and is unable to synthesize porphyrins. Its features can vary under certain conditions. Catalase and cytochromes may be formed in the presence of hemes and lactic acid can be further metabolized, resulting in lower lactic acid concentrations. Cell division occurs in one plane, except pediococci. The cells are usually nonmotile. They have a requirement for complex growth factors such as vitamins and amino acids. An unequivocal definition of LAB is not possible (Axelsson, Lac…
Heat-Treated Bifidobacterium longum CECT-7347: A Whole-Cell Postbiotic with Antioxidant, Anti-Inflammatory, and Gut-Barrier Protection Properties
2021
Non-viable preparations of probiotics, as whole-cell postbiotics, attract increasing interest because of their intrinsic technological stability, and their functional properties, such as immune system modulation, gut barrier maintenance, and protection against pathogens. However, reports on Bifidobacteria-derived postbiotics remain scarce. This study aims to demonstrate the functional properties of a heat-treated (HT), non-viable, Bifidobacterium longum strain, CECT-7347, a strain previously selected for its anti-inflammatory phenotype and ability to improve biomarkers of intestinal integrity in clinical trials. The study used the nematode Caenorhabditis elegans and HT-29 cell cultures as e…
Human CD4 T-Cells With a Naive Phenotype Produce Multiple Cytokines During Mycobacterium Tuberculosis Infection and Correlate With Active Disease
2018
T-cell-mediated immune responses play a fundamental role in controlling Mycobacterium tuberculosis (M. tuberculosis) infection, and traditionally, this response is thought to be mediated by Th1-type CD4+ T-cells secreting IFN-γ. While studying the function and specificity of M. tuberculosis-reactive CD4+ T-cells in more detail at the single cell level; however, we found a human CD4+ T-cell population with a naive phenotype that interestingly was capable of producing multiple cytokines (TCNP cells). CD4+ TCNP cells phenotyped as CD95lo CD28int CD49dhi CXCR3hi and showed a broad distribution of T cell receptor Vβ segments. They rapidly secreted multiple cytokines in response to different M. t…
Harnessing Unconventional T Cells for Immunotherapy of Tuberculosis
2020
Even if the incidence of tuberculosis (TB) has been decreasing over the last years, the number of patients with TB is increasing worldwide. The emergence of multidrug-resistant and extensively drug-resistant TB is making control of TB more difficult. Mycobacterium bovis bacillus Calmette–Guérin vaccine fails to prevent pulmonary TB in adults, and there is an urgent need for a vaccine that is also effective in patients with human immunodeficiency virus (HIV) coinfection. Therefore, TB control may benefit on novel therapeutic options beyond antimicrobial treatment. Host-directed immunotherapies could offer therapeutic strategies for patients with drug-resistant TB or with HIV and TB coinfecti…
The swinholide biosynthesis gene cluster from a terrestrial cyanobacterium, Nostoc sp. strain UHCC 0450
2017
ABSTRACT Swinholides are 42-carbon ring polyketides with a 2-fold axis of symmetry. They are potent cytotoxins that disrupt the actin cytoskeleton. Swinholides were discovered from the marine sponge Theonella sp. and were long suspected to be produced by symbiotic bacteria. Misakinolide, a structural variant of swinholide, was recently demonstrated to be the product of a symbiotic heterotrophic proteobacterium. Here, we report the production of swinholide A by an axenic strain of the terrestrial cyanobacterium Nostoc sp. strain UHCC 0450. We located the 85-kb trans -AT polyketide synthase (PKS) swinholide biosynthesis gene cluster from a draft genome of Nostoc sp. UHCC 0450. The swinholide …