Bioinformatics investigation of CRISPR/Cas systems in Bifidobacterium longum

Bifidobacterium longum is one of the most important probiotics used in the food industries. These bacteria are also applied for the treatment or prevention of gastrointestinal and gynecological diseases as well the regulation of immune system. On the other hand, the discovery of clustered regularly interspaced short palindromic repeats (CRISPR) systems has revolutionized gene therapy approaches and provided a novel tool for gene editing. Several investigators are seeking for potential CRISPR sequences as well the CRISPR-associated (Cas) proteins in various microorganism. Considering the importance of B. longum and its safe application in food industry, the aim of the present study is to investigate the presence and characteristics of CRISPRs in this bacterium via in silico study in 96 strains of the bacteria. According to the results obtained in this study, nine B. longum strains demonstrated high occurrence of CRISPR arrays. These arrays could probably form four RNA secondary structures. Since the bacterium B. longum have been widely used as a safe microorganism in foods, the first report on the probable presence of CRISPR sequences may provide the opportunity to introduce the bacteria as a gene editing tool.