Search results for "bacterium"
showing 10 items of 595 documents
Production of High Amounts of Hepatotoxin Nodularin and New Protease Inhibitors Pseudospumigins by the Brazilian Benthic Nostoc sp. CENA543
2017
Nostoc is a cyanobacterial genus, common in soils and a prolific producer of natural products. This research project aimed to explore and characterize Brazilian cyanobacteria for new bioactive compounds. Here we report the production of hepatotoxins and new protease inhibitors from benthic Nostoc sp. CENA543 isolated from a small, shallow, saline-alkaline lake in the Nhecolandia, Pantanal wetland area in Brazil. Nostoc sp. CENA543 produces exceptionally high amounts of nodularin-R. This is the first free-living Nostoc that produces nodularin at comparable levels as the toxic, bloom-forming, Nodularia spumigena. We also characterized pseudospumigins A-F, which are a novel family of linear te…
Photobacterium malacitanum sp. nov., and Photobacterium andalusiense sp. nov., two new bacteria isolated from diseased farmed fish in Southern Spain.
2018
Three strains, H01100409BT, H01100413B, and H27100402HT, were isolated from several internal organs of diseased redbanded seabream (Pagrus auriga) reared in Andalusia (Southern Spain). All strains were studied by phenotypic, including chemotaxonomy, and genomic characteristics. Phylogenetic analysis based on concatenated sequences of six housekeeping genes (gyrB, ftsZ, topA, mreB, gapA, and 16S rRNA) supported the inclusion of the strains within the clade Phosphoreum of the genus Photobacterium, and two of the strains (H27100402HT and H01100409BT) formed a tight group separated from the closest species P. aquimaris. Genomic analyses, including average nucleotide identity (ANIb and ANIm) and…
Photobacterium toruni sp. nov., a bacterium isolated from diseased farmed fish.
2017
Three bacterial strains were isolated from liver and spleen of diseased farmed redbanded seabream (Pagrus auriga) in south-west Spain. Their partial 16S rRNA gene sequences clustered within those of the genus Photobacterium , showing high similarity (98.6–99.3 %) to the type strains of Photobacterium iliopiscarium , P. piscicola , P. kishitanii , P. aquimaris and P. phosphoreum . Multilocus sequence analysis using six housekeeping genes (gapA, topA, mreB, ftsZ, gyrB and 16S rRNA) confirmed the new strains as forming an independent branch with a bootstrap value of 100, likely to represent a novel species. To confirm this, we used whole genome sequencing and genomic analysis (ANIb, ANIm and i…
Phylogenomics of Mycobacterium africanum reveals a new lineage and a complex evolutionary history.
2021
Coscolla et al.
Intensive aquaculture selects for increased virulence and interference competition in bacteria
2016
Although increased disease severity driven by intensive farming practices is problematic in food production, the role of evolutionary change in disease is not well understood in these environments. Experiments on parasite evolution are traditionally conducted using laboratory models, often unrelated to economically important systems. We compared how the virulence, growth and competitive ability of a globally important fish pathogen, Flavobacterium columnare , change under intensive aquaculture. We characterized bacterial isolates from disease outbreaks at fish farms during 2003–2010, and compared F. columnare populations in inlet water and outlet water of a fish farm during the 2010 outbre…
Human milk and mucosa-associated disaccharides impact on cultured infant fecal microbiota
2020
Human milk oligosaccharides (HMOs) are a mixture of structurally diverse carbohydrates that contribute to shape a healthy gut microbiota composition. The great diversity of the HMOs structures does not allow the attribution of specific prebiotic characteristics to single milk oligosaccharides. We analyze here the utilization of four disaccharides, lacto-N-biose (LNB), galacto-N-biose (GNB), fucosyl-α1,3-GlcNAc (3FN) and fucosyl-α1,6-GlcNAc (6FN), that form part of HMOs and glycoprotein structures, by the infant fecal microbiota. LNB significantly increased the total levels of bifidobacteria and the species Bifidobacterium breve and Bifidobacterium bifidum. The Lactobacillus genus levels wer…
Complete Genome Sequence of an Aquaculture-Associated Phage, FL-1, Infecting Flavobacterium spp
2017
Flavobacterium spp. are abundant and widespread in freshwater environments (1, 2). Despite the prevalence of the members in this genus, the phages infecting Flavobacterium spp. are less known. So far, most of the phages studied in detail infect fish pathogenic members of the genus, such as F. psychrophilum (3). The phage FL-1 and its Flavobacterium sp. host strain B183 were previously isolated from a water sample from a fish farm in Central Finland. Transmission electron microscopy revealed FL-1 to be a member of the family Myoviridae (4). In addition to the isolation host, FL-1 also infects multiple Flavobacterium sp. isolates and strains of the fish pathogen F. columnare, the causative ag…
DNA Damage Signaling Instructs Polyploid Macrophage Fate in Granulomas.
2018
Granulomas are immune cell aggregates formed in response to persistent inflammatory stimuli. Granuloma macrophage subsets are diverse and carry varying copy numbers of their genomic information. The molecular programs that control the differentiation of such macrophage populations in response to a chronic stimulus, though critical for disease outcome, have not been defined. Here, we delineate a macrophage differentiation pathway by which a persistent Toll-like receptor (TLR) 2 signal instructs polyploid macrophage fate by inducing replication stress and activating the DNA damage response. Polyploid granuloma-resident macrophages formed via modified cell divisions and mitotic defects and not…
First molecular detection of mycobacterium bovis in environmental samples from a French region with endemic bovine tuberculosis
2016
Aims The aim of the study was to determine the prevalence of Mycobacterium bovis (the causative agent of bovine tuberculosis, bTB) in environmental matrices within a French region (Cote d'Or) affected by this zoonotic disease. Methods and Results We report here the development and the use of molecular detection assays based on qPCR (double fluorescent dye labelled probe) to monitor the occurrence of Mycobacterium tuberculosis complex (MTBC) or M. bovis in environmental samples collected in pastures where infected cattle and wildlife had been reported. Three qPCR assays targeting members of the MTBC (IS1561’ and Rv3866 loci) or M. bovis (RD4 locus) were developed or refined from existing ass…
Coinfection outcome in an opportunistic pathogen depends on the inter-strain interactions
2017
Background In nature, organisms are commonly coinfected by two or more parasite strains, which has been shown to influence disease virulence. Yet, the effects of coinfections of environmental opportunistic pathogens on disease outcome are still poorly known, although as host-generalists they are highly likely to participate in coinfections. We asked whether coinfection with conspecific opportunistic strains leads to changes in virulence, and if these changes are associated with bacterial growth or interference competition. We infected zebra fish (Danio rerio) with three geographically and/or temporally distant environmental opportunist Flavobacterium columnare strains in single and in coinf…