Human gut microbiome is associated with various diseases, including autism spectrum disorders (ASD). Variations of the taxonomical composition in the gut microbiome of children with ASD have been observed repeatedly. However, features and parameters of the CRISPR-Cas systems in the gut microbiome of children with ASD have not been investigated yet. Here we demonstrate such an analysis in comparison with the healthy microbiome. For the identification of CRISPR-Cas systems, we used a combination of the publicly available tools suited for completed genomes with subsequent filtrations. In all considered datasets, the microbiomes of children with ASD contained fewer arrays per Gb of assembly, than the control group, but the arrays included more spacers on average. These patterns were observed systematically in our datasets, although their statistical significance hardly matched the thresholds. CRISPR arrays from the microbiomes of children with ASD differed from the control group neither in the fractions of spacers with protospacers from known genomes, nor in the sets of known bacteriophages providing protospacers. The majority of bacterial protospacers of the gut microbiome systems for both children with ASD and the healthy ones was located in the prophage islands.

Strain L. fermentum U-21 secretes chaperones into the medium and it is considered as the candidate for the development of drugs, so-called disaggregases, for Parkinson’s disease therapy. This study is devoted to characterization of secreted protein encoded by C0965_000195 locus. Analysis of sequence and predicted structure of the protein encoded by C0965_000195 allows us to attribute it to the ClpL, homologs of which are known to be chaperones. The chaperone activity of ClpL L. fermentum U-21 was evaluated in vivo by refolding of differing in thermostability luciferases from Aliivibrio fischeri and Photorhabdus luminescens in Escherichia coli cells. It was observed that clpL from L. fermentum U-21 can compensate for the deficiency in the clpB gene and enhance the ability to refold thermodenatured proteins in clpB- cells. In vitro experiments have demonstrated the ability of a spent culture medium containing proteins secreted by L. fermentum U-21 cells, including ClpL, to prevent thermodenaturation of luciferases partially.We suggest that the ClpL protein from L. fermentum U-21 strain, which exhibits disaggregase properties against aggregating proteins, may be one of the clue components that play a role in the pharmabiotic properties of this strain.