ABSTRACT
Tuberculosis (TB) is a communicable disease caused by Mycobacterium tuberculosis (M. tuberculosis). WHO estimated that 10.4 million new (incident) TB cases worldwide in year 2016. The increased prevalence of drug resistant strains and side effects associated with the current anti-tubercular drugs make the treatment options more complicated. Hence, there are necessities to identify new drug candidates to fight against various sub-populations of M. tuberculosis with less or no toxicity/side effects and shorter treatment duration. Bacteriocins produced by lactic acid bacteria (LAB) attract attention of researchers because of its 'Generally recognized as safe' status. LAB and its bacteriocins possess an effective antimicrobial activity against various bacteria and fungi. Interestingly bacteriocins such as nisin and lacticin 3147 have shown antimycobacterial activity in vitro. As probiotics, LAB plays a vital role in promoting various health benefits including ability to modulate immune response against various infectious diseases. LAB and its metabolic products activate immune system and thereby limiting the M. tuberculosis pathogenesis. The protein and peptide engineering techniques paved the ways to obtain hybrid bacteriocin derivatives from the known peptide sequence of existing bacteriocin. In this review, we focus on the antimycobacterial property and immunomodulatory role of LAB and its metabolic products. Techniques for large scale synthesis of potential bacteriocin with multifunctional activity and enhanced stability are also discussed.
ABSTRACT
An attempt was made for the isolation of colicinogenic E. coli from cow and sheep dung samples. Total of 112 E. coli isolates were collected from sheep and cow dung samples in which 63 isolates are from cow dung and 49 isolates are from sheep dung samples. In the screening for colicin production, two E. coli isolates C22 and C51 from cow dung sample and one isolate S39 from sheep dung sample showed activity against the pathogenic strain E. coli O157:H7. Colicin production by all the three E. coli isolates was found to be enhanced by 0.25mg/l of mitomycin-c and three hours of incubation at 370C. Plasmid DNA was isolated from colicinogenic E. coli strains by alkali lysis method and their molecular weight was found to be 6.5 kb. The transformation experiment carried out with the standard strain E. coli DH5 confirmed that the plasmids were col-plasmids. The three colicinogenic E. coli strains isolated in this study will be a candidate to develop as probiotic for veterinary applications.