Notes

Usage of evidence from reports without events inside meta-analyses involving undesirable events: the scientific study.
an Society for Microbiology.Azotobacter vinelandii is an obligate aerobic diazotroph with verified transient capability to reduce carbon monoxide to ethylene by its vanadium nitrogenase. In this study, we implemented an industrially relevant continuous two-stage stirred-tank system for in vivo biotransformation of a controlled supply of air enriched with 5% carbon monoxide to 302 μg ethylene g-1 glucose consumed. To attain this value, the process required overcoming critical oxygen limitations during cell proliferation while simultaneously avoiding the A. vinelandii respiratory protection mechanism that negatively impacts in vivo nitrogenase activity. Additionally, process conditions allowed for the demonstration of carbon monoxide's solubility as a reaction-limiting factor and a competitor with dinitrogen for the vanadium nitrogenase active site; implying that excess intracellular carbon monoxide could lead to a cessation of cell proliferation and ethylene formation as shown genetically using a new strain of A. vinelandii deficient in carbon monoxide dehydrogenase.IMPORTANCE Ethylene is an essential commodity feedstock used for the generation of a variety of consumer products, but its generation demands energy intensive processes and is dependent on nonrenewable substrates. This work describes a continuous biological method for investigating the nitrogenase-mediated carbon monoxide reductive coupling involved in ethylene production using whole cells of Azotobacter vinelandii If eventually adopted by industry, this white technology has the potential to significantly lower the total energy inputs, ethylene recovery costs, as well as decreasing greenhouse gas emissions associated with current production strategies. Copyright © 2020 American Society for Microbiology.Our current understanding of the host-microbiota interaction in the gut is dominated by studies focused primarily on prokaryotic bacterial communities. However, there is an underappreciated symbiotic eukaryotic protistic community that is an integral part of mammalian microbiota. How commensal protozoan-bacteria might interact to form a stable microbial community remains poorly understood. Here, we described a murine protistic commensal phylogenetically assigned as Tritrichomonas musculis, whose colonization in the gut resulted in a reduction of gut bacterial abundance and diversity in wild-type C57BL/6 mice. Selleckchem Protosappanin B Meanwhile, dietary nutrient and commensal bacteria also influenced the protozoan's intestinal colonization and stability. While mice fed on normal chow diet had abundant T. musculis, switching to a Western-type high-fat diet led to the diminishment of the protozoan from the gut. Supplementation of inulin as a dietary fiber to the high-fat diet partially restored the protozoan's colonization. In addition,crobial community dysfunctions to promote the host's health or to treat diseases. Copyright © 2020 American Society for Microbiology.The N-acetylglucosaminidase LytB of Streptococcus pneumoniae is involved in nasopharyngeal colonization and responsible for cell separation at the end of cell division; ΔlytB mutants form long chains of cells. This paper reports the construction and properties of a defective pneumococcal mutant producing an inactive LytB protein (LytBE585A). It is shown that an enzymatically active LytB is required for in vitro biofilm formation, this is, lytB mutants (either ΔlytB or producing the inactive LytBE585A) are incapable of forming substantial biofilms, even although extracellular DNA is present in the biofilm matrix. Adding small amounts (0.5-2.0 μg/ml) of exogenous LytB or some LytB constructs restored the biofilm-forming capacity of lytB mutants to wild-type levels. The LytBE585A mutant formed biofilm more rapidly than ΔlytB mutants in the presence of LytB. This suggests that the mutant protein that was present acted in a structural role, likely through the formation of complexes with extracellular DNA. The chain-dispersing capacity of LytB allowed the separation of daughter cells, presumably facilitating the formation of microcolonies and, finally, of biofilms. A role for the possible involvement of LytB in the synthesis of the extracellular polysaccharide component of the biofilm matrix is also discussed.IMPORTANCE It had been accepted that biofilm formation in S. pneumoniae is a multigenic trait because the mutation of just one gene might lead only to a partial inhibition of biofilm production. In the present study, however, evidence that the N-acetylglucosaminidasa LytB is crucial in biofilm formation is provided. Although extracellular DNA was present, either deficient or defective lytB mutants only formed shallow biofilms. Copyright © 2020 American Society for Microbiology.Dietary protein residue can result in microbial generation of various toxic metabolites in the gut, such as ammonia. A prebiotic is "a substrate that is selectively utilised by host microorganisms conferring a health benefit". Prebiotics are carbohydrates that may have the potential to reverse the harmful effects of gut bacterial protein fermentation.Three-stage continuous colonic model systems were inoculated with faecal samples from omnivore and vegetarian volunteers. Casein (equivalent to 105g protein consumption per day) was used within the systems as a fermentab274; le protein source. Two different doses of inulin type fructans (Synergy1) were later added (equivalent to 10g per day in vivo and 15g per day) to assess whether this influenced protein fermentation. Bacteria were enumerated by fluorescence in situ hybridisation with flow cytometry. Metabolites from bacterial fermentation (short chain fatty acid (SCFA), ammonia, phenol, indole and p-cresol) were monitored to further analyse proteolysis and theved both bacterial and metabolic differences between faecal bacteria from omnivore donors and vegetarian donors. Proteins with prebiotic supplementation showed higher Bacteroides spp. and inhibited clostridial cluster IX in omnivore models while in vegetarian modes, clostridial cluster IX were higher and Bacteroides spp. lowered with high protein plus prebiotic supplementation. Synergy1 addition inhibited p-cresol production in vegetarian high p-cresol producing models while the inhibitory effect was not seen in omnivore models. Copyright © 2020 American Society for Microbiology.
Read More: https://www.selleckchem.com/products/protosappanin-b.html