Edible marine algae: a new source for anti-mycobacterial agents.

Tuberculosis is a dreaded disease, which causes innumerable death worldwide. The emergence of drug resistance strains makes the situation devastating. Therefore, for better management of public health, it is mandatory to search for new anti-mycobacterial agents. In this context, the current study investigated two edible marine algae, Ulva lactuca and Ulva intestinalis, for the probable source of new anti-mycobacterial agents. To test the anti-mycobacterial activity, alcoholic extracts of these two algae were spotted on the Mycobacterium smegmatis lawn. Upon incubation, clear zone was observed at the spots. It indicated that these two extracts have anti-mycobacterial activity. In addition, their anti-biofilm property was also tested. It was found that both the extracts inhibit the mycobacterial biofilm development as well as they can disperse the preformed mycobacterial biofilm. Since these two are capable of dispersing preformed mycobacterial biofilm, it is possible that in the presence of either of these two extracts, isoniazid and rifampicin can kill biofilm encapsulated mycobacterium in combinatorial therapy. Consistent with the hypothesis, rifampicin and isoniazid killed mycobacteria that were present in biofilm. Thus, these two extracts augment the activity of rifampicin and isoniazid upon biofilm dispersal. Moreover, treatment of different cell lines with these two extracts exhibited no or little cytotoxic effects. Thus, these two agents have the potential to be good therapeutic agents against mycobacterial diseases.

Nitrogen dynamics of the aquatic system is an important driving force for efficient sewage purification in single pond natural treatment wetlands at East Kolkata Wetland.

At East Kolkata Wetlands, though the domestic city sewage is purified very rapidly, the mechanisms of treatment remains inadequately explored. In this context, the present study investigated nitrogen dynamics of the single pond treatment systems during purification and explored its potential role in sewage treatment. For this purpose the concentrations of different forms of nitrogen present both in water and soil at different time points of purification were measured. The organic nitrogen content decreased sharply, in the early phase, with an increase in ammonium concentration. Notably the reduction in organic nitrogen was significantly higher than the increase in NH4+ which can be attributed to the volatilization of NH4+ under alkaline pH. This volatilization results in reduced oxygen demand. The nitrate-N concentration decreased sharply from soil with a concomitant increase in water column. However the reduction of nitrate in soil was significantly higher than the increase in water column. It indicated the occurrence of denitrification under anoxic condition wherein nitrate serves as terminal electron acceptor. Additionally a part of the nitrate supported planktonic growth. Thus it describes another mechanism of reducing oxygen demand. The initial NH4+-N concentration in the soil was very low and it increased gradually during purification due to increasing soil cation exchange capacity. Thus by trapping NH4+ ion soil contributes towards preventing contamination of water. Thus at EKW, the cumulative activities in water and soil involved in nitrogen dynamics lead to overall reduction of the oxygen demand and contribute towards efficient sewage purification.

Vitamin C prevents cigarette smoke induced atherosclerosis in guinea pig model.

AIM: Cigarette smoking is a major risk for developing atherosclerosis; however, the underlying mechanism is poorly understood. This paucity of knowledge is largely attributed to the lack of an animal model; therefore, our efforts were targeted towards establishing cigarette smoke (CS)-induced atherosclerosis in guinea pig. To understand the mechanism, we investigated apoptosis, an event implicated in atherosclerosis, in the aorta of CS-exposed animals. Since a major deleterious effect of CS is oxidative stress, we also examined the effect of vitamin C, an antioxidant, on CS- induced atherosclerosis. METHODS AND RESULTS: Guinea pigs on a diet with or without vitamin C supplement were exposed to CS for different time periods. Aortal sections from these animals were examined for atherosclerotic changes by staining with H&E and Oil red O. Atherogenic changes were observed in sections obtained from CS-exposed guinea pigs only. TUNEL assay showed the occurrence of apoptosis in CS-exposed guinea pig aorta. Our results revealed that CS-induced apoptosis could contribute to the progression but not to the initiation of the disease. Immunohistochemical analysis documents that CS-induced apoptosis in aortal sections is mediated at least in part by an increased Bax/Bcl2 ratio. In contrast, CS-exposed guinea pigs fed with vitamin C-supplemented diet exhibit little or no atherogenic changes. This anti-atherosclerotic activity of vitamin C can be attributed partly to its ability to inhibit CS-induced apoptosis and platelet activation. CONCLUSION: Exposure of guinea pigs to cigarette smoke causes the development of atherosclerosis, which can be prevented by vitamin C supplement.