Project description:Short open reading frames (sORF) have the potential to encode small proteins in the human gut microbiome, but their role in this environment is rarely understood. These small proteins, known as sORF-encoded peptides (SEP), are less than or equal to 100 amino acids in length. Using bottom-up proteomics (BUP) and top-down proteomics (TDP) approaches, we aimed to identify SEP under various growth conditions and stress exposure in Blautia producta, a key species in mediating colonization resistance and dampening gut inflammation. After applying a rigorous filtering and validation procedure, we identified 45 SEP. Our findings indicate that in contrast to previous results the production of specific SEP is not restricted to direct bacterial interactions within the microbiome but rather depends on growth and stress conditions of the environment. Top-down analysis improved identification confidence and detected a number of full-length with and without N-terminal methionine excision (NME), N- or C-terminal truncated or post-translational modified proteoforms of SEP, indicating that these are common occurrences in B. producta. These findings highlight SEP as a ubiquitous class of non-annotated polypeptides that have been overlooked as a subset of proteins in B. producta.
Project description:In recent years, Blautia has attracted attention for its role in ameliorating host diseases. In particular, Blautia producta DSM 2950 has been considered a potential probiotic due to its ability to mitigate inflammation in poly(I:C) induced HT-29 cells. Thus, to promote the development of indigenous intestinal microorganisms with potential probiotic function, we conducted a comprehensive experimental analysis of DSM 2950 to determine its safety. This comprised a study of its potential virulence genes, antibiotic resistance genes, genomic islands, antibiotic resistance, and hemolytic activity and a 14-day test of its acute oral toxicity in mice. The results indicated no toxin-related virulence genes in the DSM 2950 genome. Most of the genomic islands in DSM 2950 were related to metabolism, rather than virulence expression. DSM 2950 was sensitive to most of the tested antibiotics but was tolerant of treatment with kanamycin, neomycin, clindamycin, or ciprofloxacin, probably because it possessed the corresponding antibiotic resistance genes. Oral acute toxicity tests indicated that the consumption of DSM 2950 does not cause toxic side effects in mice. Overall, the safety profile of DSM 2950 confirmed that it could be a candidate probiotic for use in food and pharmaceutical preparations.