Elevated exposure to arsenic has been suggested to be associated with atherosclerosis leading to cardiovascular disease (CVD). However, biochemical events underlying the arsenic-induced atherosclerosis have not yet been fully documented. The aim of this study was to investigate the associations of circulating molecules involved in atherosclerosis with arsenic exposure in the individuals exposed to arsenic in Bangladesh. A total of 324 study subjects, 218 from arsenic-endemic areas and 106 from nonendemic areas in Bangladesh, were recruited. Drinking water, hair, nail, and blood samples were collected from the study subjects for analysis. Total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) levels were lower in arsenic-endemic subjects than those of nonendemic subjects. Oxidized LDL (Ox-LDL), C-reactive protein (CRP), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) levels were significantly higher in arsenic-endemic subjects than those in nonendemic subjects. All these circulating molecules showed significant correlations with arsenic exposure (water, hair, and nail arsenic concentrations), and all these relations were significant before and after adjusting for relevant covariates. Among the circulating molecules tested in this study, HDL, Ox-LDL, and CRP showed dose-response relationships with arsenic exposure. Ox-LDL/HDL ratios were increased with the increasing concentrations of arsenic in the water, hair, and nails. Furthermore, non-HDL cholesterol and TC/HDL ratios were significantly correlated with arsenic exposure before and after adjusting for relevant covariates. Thus, all the observed associations may be the major features of arsenic exposure-related atherosclerosis leading to CVD.

An actinomycete strain was isolated from northern part of Bangladesh and identified as a new Streptomyces species on the basis of its morphological, biochemical, cultural characteristics and 16S rRNA data. Attempts were made to optimize the culture conditions for the production of antimicrobial metabolites by this strain. Antimicrobial metabolites production was started after 7 days of incubation of culture broth and reached its maximum levels after 10 days and thereafter gradually decreased. The maximum production of antimicrobial metabolites was obtained when the culture medium pH was adjusted to 8. The optimum temperature for antimicrobial metabolites production was 39℃, indicated the new strain as mesophilic organism. Basel medium supplemented with glucose and yeast extract as carbon and nitrogen sources, respectively, was proved to be the best for the production of bioactive metabolites. Maximum production of bioactive metabolites was when NaCl concentration was 1% and among different minerals tested, K2HPO4 and NaCl showed positive influence on antibiotic production by the strain.

It can be concluded that, potent antibacterial and antifungal phytochemicals are present in ethanol extract of Z. zerumbet (L).

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