Streptomyces antibioticalis, a Novel Species from a Sanitary Landfill Soil.

A novel isolate belonging to the genus Streptomyces, strain SL-4(T), was isolated from soil sample collected from a sanitary landfill, New Delhi, India. The taxonomic status of this isolate was studied by polyphasic approach including morphological, physiological and chemo-taxonomic characterization. Spore chains of SL-4(T) were open loops, hooks or extended spirals of wide diameter (retinaculiperti). The cell wall peptidoglycan of the isolate SL-4(T) contained L,L-diaminopimelic acid, suggesting that the strain has a cell wall of chemotype-I. The polar lipid profile of the isolate was of Type II, with phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The 16SrRNA gene sequence similarity between SL-4(T) and its phylogenetic relatives Streptomyces atrovirens NRRLB 16357 (T) (DQ026672), S. albogriseolus NRRLB 1305 (T) (AJ494865), S viridodiastaticus NBRC 13106 (T) (AB184317), S. caelestis NRRL 2418 (T) (X80824), S. flavoviridis NBRC 12772 (T) (AB184842), S. pilosus NBRC 12807 (T) (AB184161) and S. longispororuber NBRC 13488 (T) (AB184440) was 99.65, 99.65, 99.64, 99.23, 99.15, 99.14 and 99.13 % respectively. Subsequent DNA-DNA hybridization experiments with the test strain and its clade members showed 55.27, 44.27, 36.86, and 15.65 % relatedness between SL-4(T) and its relatives S. atrovirens, S. albogriseolus, S. viridodiastaticus and S. longispororuber respectively. The genotypic and phenotypic data was analyzed to verify possibility of the isolate SL-4(T) representing novel member of the genus Streptomyces, for which the name S. antibioticalis is being proposed. The type strain is SL-4(T) (=CCM 7434(T)=MTCC 8588(T)).

Bioactive compounds from marine actinomycetes.

Actinomycetes are one of the most efficient groups of secondary metabolite producers and are very important from an industrial point of view. Among its various genera, Streptomyces, Saccharopolyspora, Amycolatopsis, Micromonospora and Actinoplanes are the major producers of commercially important biomolecules. Several species have been isolated and screened from the soil in the past decades. Consequently the chance of isolating a novel actinomycete strain from a terrestrial habitat, which would produce new biologically active metabolites, has reduced. The most relevant reason for discovering novel secondary metabolites is to circumvent the problem of resistant pathogens, which are no longer susceptible to the currently used drugs. Existence of actinomycetes has been reported in the hitherto untapped marine ecosystem. Marine actinomycetes are efficient producers of new secondary metabolites that show a range of biological activities including antibacterial, antifungal, anticancer, insecticidal and enzyme inhibition. Bioactive compounds from marine actinomycetes possess distinct chemical structures that may form the basis for synthesis of new drugs that could be used to combat resistant pathogens.