Project description:Commercial probiotic bacteria must be tested for acquired antibiotic resistance elements to avoid potential transfer to pathogens. The European Food Safety Authority recommends testing resistance using microdilution culture techniques previously used to establish inhibitory thresholds for the Bifidobacterium genus. Many Bifidobacterium animalis subsp. lactis strains exhibit increased resistance to tetracycline, historically attributed to the ribosomal protection gene tet(W). However, some strains that harbor genetically identical tet(W) genes show various inhibition levels suggesting that other genetic elements also contribute to observed differences. Here, we adapted several molecular assays to confirm the inhibition of B. animalis subsp. lactis strains Bl-04 and HN019, and employed RNA-seq to assess the transcriptional differences related to genomic polymorphisms. We detected specific stress responses to the antibiotic by correlating ATP concentration to viable genome copies from droplet digital PCR, and found that the bacteria were still metabolically active in high drug concentrations. Transcriptional analyses revealed that several polymorphic regions, particularly a novel multi-drug efflux transporter, were differentially expressed between the strains in each experimental condition, likely having phenotypic effects. We also found that the tet(W) gene was up-regulated only during sub-inhibitory tetracycline concentrations, while two novel tetracycline resistance genes were up-regulated at high concentrations. Furthermore, many genes involved in amino acid metabolism and transporter function were up-regulated while genes for complex carbohydrate utilization, protein metabolism, and CRISPR-Cas systems were down-regulated. These results provide high-throughput means for assessing antibiotic resistance and determine the genetic network that contributes to the global tetracycline response between two highly related probiotic strains.
Project description:Modulation of gut microbiota through probiotic supplementation is an interesting strategy to prevent obesity We use microarrays to study the global genome expression of C. elegans fed with the probiotic strain Bifidobacterium animalis sbsp. lactis CECT 8145
Project description:Bifidobacterium animalis subsp. lactis BLC1 is a probiotic bacterium that is widely exploited by food industries as the active ingredient of various functional foods. Here we report the complete genome sequence of B. animalis subsp. lactis BLC1, which is expected to provide insights into the biology of this health-promoting microorganism and improve our understanding of its phylogenetic relatedness with other members of the B. animalis subsp. lactis taxon.
Project description:All strains of Bifidobacterium animalis subsp. lactis described to date show medium level resistance to tetracycline. Screening of 26 strains from a variety of sources revealed the presence of tet(W) in all isolates. A transposase gene upstream of tet(W) was found in all strains, and both genes were cotranscribed in strain IPLAIC4. Mutants with increased tetracycline resistance as well as tetracycline-sensitive mutants of IPLAIC4 were isolated and genetically characterized. The native tet(W) gene was able to restore the resistance phenotype to a mutant with an alteration in tet(W) by functional complementation, indicating that tet(W) is necessary and sufficient for the tetracycline resistance seen in B. animalis subsp. lactis.
Project description:Modulation of gut microbiota through probiotic supplementation is an interesting strategy to prevent obesity We use microarrays to study the global genome expression of C. elegans fed with the probiotic strain Bifidobacterium animalis sbsp. lactis CECT 8145 Wild type strain N2 of C. elegans was cutured in Nematode Growth medium (NGM, control fed) or NGM with a bacterial lawn fed of the strain B. animalis subsp. lactis CECT 8145, until reach young adult stage. Worm population were age-synchronized. RNA was isolated from each populations (control and treated) using RNAasy Kit (Qiagen) and hybridizated on Affymetrix microarrays.
Project description:Bifidobacterium animalis subsp. lactis is a probiotic bacterium that naturally inhabits the guts of most mammals, including humans. Here we report the complete genome sequence of B. animalis subsp. lactis AD011 that was isolated from an infant fecal sample. Biological functions encoded in a single circular chromosome of 1,933,695 bp, smallest among the completely sequenced bifidobacterial genomes, are suggestive of their probiotic functions, such as utilization of bifidogenic factors and a variety of glycosidic enzymes and biosynthesis of polysaccharides.
Project description:Bifidobacterium animalis subsp. lactis strain V9 is a Chinese commercial bifidobacteria with several probiotic functions. It was isolated from a healthy Mongolian child in China. We present here the complete genome sequence of V9 and compare it to 3 other published genome sequences of B. animalis subsp. lactis strains. The result indicates the lack of polymorphism among strains of this subspecies from different continents.
Project description:Commercial probiotic bacteria must be tested for acquired antibiotic resistance elements to avoid potential transfer to pathogens. The European Food Safety Authority recommends testing resistance using microdilution culture techniques previously used to establish inhibitory thresholds for the Bifidobacterium genus. Many Bifidobacterium animalis subsp. lactis strains exhibit increased resistance to tetracycline, historically attributed to the ribosomal protection gene tet(W). However, some strains that harbor genetically identical tet(W) genes show various inhibition levels, suggesting that other genetic elements also contribute to observed differences. Here, we adapted several molecular assays to confirm the inhibition of B. animalis subsp. lactis strains Bl-04 and HN019 and employed RNA sequencing to assess the transcriptional differences related to genomic polymorphisms. We detected specific stress responses to the antibiotic by correlating ATP concentration to number of viable genome copies from droplet digital PCR and found that the bacteria were still metabolically active in high drug concentrations. Transcriptional analyses revealed that several polymorphic regions, particularly a novel multidrug efflux transporter, were differentially expressed between the strains in each experimental condition, likely having phenotypic effects. We also found that the tet(W) gene was upregulated only during subinhibitory tetracycline concentrations, while two novel tetracycline resistance genes were upregulated at high concentrations. Furthermore, many genes involved in amino acid metabolism and transporter function were upregulated, while genes for complex carbohydrate utilization, protein metabolism, and clustered regularly interspaced short palindromic repeat(s) (CRISPR)-Cas systems were downregulated. These results provide high-throughput means for assessing antibiotic resistances of two highly related probiotic strains and determine the genetic network that contributes to the global tetracycline response.IMPORTANCEBifidobacterium animalis subsp. lactis is widely used in human food and dietary supplements. Although well documented to be safe, B. animalis subsp. lactis strains must not contain transferable antibiotic resistance elements. Many B. animalis subsp. lactis strains have different resistance measurements despite being genetically similar, and the reasons for this are not well understood. In the current study, we sought to examine how genomic differences between two closely related industrial B. animalis subsp. lactis strains contribute to different resistance levels. This will lead to a better understanding of resistance, identify future targets for analysis of transferability, and expand our understanding of tetracycline resistance in bacteria.
Project description:Although intestinal microbiota play a pivotal role in the development of host immune system this biological issue was not so far studied in great detail. In this study we examined immune response of Caco-2 enterocytes after incubation with common probiotic Bifidobacterium animalis subsp. lactis BB-12 for 4 hours. We used microarrays to inspect the global gene expression of Caco-2 cells upon co-culturing with B. animalis subsp. lactis BB-12 and several distinct immune-related genes up-regulated during this process.