Genomic and functional characterization of a strain isolated from human gut microbiota.

The gut is the most complex microbial ecosystem in the body that greatly influences human immune and metabolic health. However, the functional understanding of gut microbiome is hampered by our limited ability to obtain bacterial cultures for experimental validation, particularly low-abundant species that may carry specific functions but are often overlooked by population-based analyses. Here, we isolated and characterized a novel strain of (named Bp 531D) from human gut microbiota, representing the first butyrate-producing human isolate within a phylogenetic clade of complex.

regulates carbohydrate metabolic functions of the gut microbiome in C57BL/6 mice.

The probiotic impact of microbes on host metabolism and health depends on both host genetics and bacterial genomic variation. is the predominant human gut commensal emerging as a next-generation probiotic. Although this bacterium exhibits substantial intraspecies diversity, it is unclear whether genetically distinct strains might lead to functional differences in the gut microbiome.

Characterization of the novel bequatrovirus vB-BcgM and its antibacterial effects in a food matrix.

Bacteria belonging to the Bacillus cereus group are ubiquitous in nature, causing food spoilage and food poisoning cases. A bequatrovirus, vB-BcgM, belonging to the C3 cluster infecting B. cereus group members, was isolated and characterized.

Characterization of vB_SalS_PSa2, a T5-like Demerecviridae bacteriophage, and its potential use in food matrices.

This study characterizes a newly isolated Demerecviridae phage, named vB_SalS_PSa2, belonging to the phage T5 group. The main variations between vB_SalS_PSa2 and T5 concern structural proteins related to morphology and host recognition. vB_SalS_PSa2 is infective to 19 out of the 25 tested Salmonella enterica (including the rare "Sendai" and "Equine" serotypes) and Escherichia coli isolates, most of them being multidrug resistant.

Interspecies Horizontal Transfer and Specific Integration of the Mosquitocidal Toxin-Encoding Plasmid pTAND672-2 from Bacillus thuringiensis subsp. to Lysinibacillus sphaericus.

pTAND672-2, a 144-kb resident plasmid of Bacillus thuringiensis serovar strain TAND672, was sequenced and characterized. This extrachromosomal element carries mosquitocidal toxin-, conjugation-, and recombinase-encoding genes, together with a putative arbitrium system, a genetic module recently discovered in temperate phages controlling lysogeny-lysis transition and in mobile genetic elements (MGEs) where its function remains clarified. Using conjugation experiments, pTAND672-2 is shown to be a novel integrative and conjugative element (ICE), which can horizontally transfer from B.

Influence of the Phagemid PfNC7401 on Cereulide-Producing NC7401.

A phagemid-cured strain, NC7401-∆Pf, was constructed to survey the biological function of the plasmidal prophage PfNC7401 in cereulide-producing NC7401. The transcriptome analysis between the mutant and the wild strains revealed a series of differentially expressed genes mainly involved in different function classifications, including the two-component signal transduction system, bacterial structure, transporters, related antibiotic response, purine biosynthesis, non-ribosomal peptide synthetases (NRPS) and related secondary metabolites, and aromatic or other amino acid synthesis. BIOLOG and phenotypic experiment analyses confirmed that PfNC7401 may affect phage immunity and the metabolism of several amino acids, including L-Alanine, which was suggested to be related to one precursor (D-Alanine) of cereulide synthesis.

Characterization and heterologous expression of a novel Co-dependent leucyl aminopeptidase Amp0279 originating from Lysinibacillus sphaericus.

This study aims to explore the potential aminopeptidases of Lysinibacillus sphaericus based on the unique metabolic characteristics of this species which cannot metabolize carbohydrates and may have a strong ability to metabolize amino acids. Fifteen peptidase-encoding genes predicted in L. sphaericus C3-41 have been heterologously expressed in Escherichia coli BL21, and of these genes, only Amp0279 shows a high ability to hydrolyze L-leucine-4-nitroanilide (Leu-pNA).

[Advances of phage receptor binding proteins].

Bacteriophages bind to the bacteria receptor through the receptor binding proteins (RBPs), a process that requires the involvement of complex atomic structures and conformational changes. In response to bacteriophage infection, bacteria have developed a variety of resistance mechanisms, while bacteriophages have also evolved multiple antagonistic mechanisms to escape host resistance. The exploration of the "adsorption-anti adsorption-escape process" between bacteriophages and bacteria helps us better understand the co-evolution process of bacteriophages and bacteria, which is important for the development of phage therapeutic technologies and phage-based biotechnologies.

Characterization of two newly isolated bacteriophages PW2 and PW4 and derived endolysins with lysis activity against Bacillus cereus group strains.

This study characterized two novel Siphoviridae phages, PW2 and PW4, that can infect 52% and 44% of the tested Bacillus cereus group isolates and display relatively high activity against four cereulide-producing isolates belonging to B. weihenstephanensis and B. paranthracis.

Horizontal transfer of large plasmid with type IV secretion system and mosquitocidal genomic island with excision and integration capabilities in Lysinibacillus sphaericus.

We identified a ~30-kb genomic island (named GI8) carrying the binary toxin gene operon binA/binB on both the chromosome and large pBsph plasmid in the mosquitocidal Lysinibacillus sphaericus C3-41 strain. We found that GI8 is related to the occurrence of binA/binB within L. sphaericus and displays excision and integration capability by recognizing the attB region, which consists of a 2-nt target site (AT) flanked by an 11-nt imperfect inverted repeat.

Application of Bacillus thuringiensis strains with conjugal and mobilizing capability drives gene transmissibility within Bacillus cereus group populations in confined habitats.

Background: Bacillus thuringiensis bacteria share similar genetic, physiological, and biochemical characteristics with other members of the Bacillus cereus group. Their diversity and entomopathogenic origin are related to their mobile genetic elements. However, the effects of wide-spread application of B.

CesH Represses Cereulide Synthesis as an Alpha/Beta Fold Hydrolase in .

Cereulide is notorious as a heat-stable emetic toxin produced by and glucose is supposed to be an ingredient supporting its formation. This study showed that glucose addition benefited on cell growth and the early transcription of genes involved in substrate accumulation and toxin synthesis, but it played a negative role in the final production of cereulide. Meanwhile, a lasting enhancement of transcription was observed with the addition of glucose.

vB_LspM-01: a novel myovirus displaying pseudolysogeny in Lysinibacillus sphaericus C3-41.

Lysinibacillus sphaericus has great application potential not only in the biocontrol of mosquitoes but also in the bioremediation of toxic metals. Phages contribute to the genetic diversity and niche adaptation of bacteria, playing essential roles in their life cycle, but may also cause economic damage for industrially important bacteria through phage contamination during fermentation. In this study, the L.

Characterization of three autolysins with activity against cereulide-producing Bacillus isolates in food matrices.

Bacillus cereus is a pathogen related with diarrhoeal or emetic food poisoning cases, of which the latter caused by the cereulide-producing isolates are more severe with several reported lethal cases. It is therefore necessary to develop an effective strategy to prevent the propagation of B. cereus in the food supply.