In vitro probiotic characterization of Lactobacillus casei isolated from marine samples

The present study evaluated probiotic potentials of marine bacteriocinogenic lactic acid bacteria (LAB).Three marine LAB isolates, designated SB71, SB73 and SB93, were characterized as Lactobacillus casei.They possessed features like high level of gastrointestinal survival, inability to form biogenic amines,adherence to Caco-2 cells and marked cholesterol assimilation. To the best of our knowledge, this is the first report about marine probiotic bacteria from the Indian subcontinent. Tolerance of the three isolates to NaCl, bile and low pH was noteworthy. EPS from SB93 markedly disrupted bacterial adherence and promoted remediation of cadmium and lead. Broad-spectrum antimicrobial and antiadhesive activities were exhibited by the SB93 bacteriocin and the active principle survived autoclaving. All three bacteriocins exhibited antimicrobial activity against Vibrio cholerae as opposed to previous results. Earlier reports mentioned that the bacteriocinogenic isolates were cultivated for 24 h following which antimicrobial action of bacteriocins (in cell-free culture supernatants) was noted. However, in the present study, the test LAB isolates were cultivated for a period of up to 5 days and bacteriocins (in cell-free supernatants collected daily from the cultures) continued to exhibit antimicrobial activity, thus advocating for their potential lasting effect in diseased individuals

Green surfactant of marine origin exerting a cytotoxic effect on cancer cell lines

The present work reveals the efficacy of a marine antimicrobial lipopeptide biosurfactant in blocking proliferation of breast cancer and colon cancer cell lines, without displaying any significant antioxidant activity. A novel isoform of 1382 Da played the key role, in sharp contrast to proliferation-blocking marine biosurfactant isoforms detected earlier in the range of 996–1077 Da and 1470–1509 Da. Inhibition of cancer cells was promoted by nanomolar concentrations of the test compound whereas much higher concentrations were reported for a few biosurfactants of marine origin as well as those of terrestrial origin like surfactin and rhamnolipids. Dual staining with annexin V and propidium iodide followed by FACS analysis showed an increased population of cancer cells at the sub G0G1 phase indicative of the programmed cell death after treatment. Although in vivo studies are yet to be done, the results of the in vitro studies displaying the cytotoxicity of this non-hemolytic marine biosurfactant product advocates for its exploitation as a potential drug candidate in anticancer chemotherapy