ABSTRACT
The search for novel antibiotics is of immense importance in research areas around the world for agricultural,pharmaceutical, and industrial applications. The Streptomyces species are widely used as an importantbiological tool for the production of a wide range of novel secondary metabolites. In the present study, isolatedstrain RSA-14 from rhizosphere soil of Alternanthera sessilis was subjected to morphological, physiological,biochemical and 16S rRNA gene sequence analysis. The isolated RSA-14 was analyzed for antimicrobialactivities by cross streak method and exhibited a broad spectrum of antimicrobial activity against test pathogens.The isolate was tested for the ability to grow in the presence of antibiotics, such as penicillin, streptomycin,chloramphenicol, gentamycin, and tetracycline and resistant to only two antibiotics, and sensitive to others. The16S ribosomal RNA gene sequencing and analysis of the phylogenetic tree showed 100% sequence similaritywith Streptomyces cinereoruber strain P.B.373.
ABSTRACT
In the present study, Pseudoxanthomonas species were isolated from rhizosphere soil samples of two selected medicinalplants, such as Alternenthera sessilis Linn. and Leucas aspera (Wild) Linn., which were collected from agriculturalfields at Kundagol, Dharwad, Karnataka. Pseudoxanthomonas sp. is Gram negative, aerobic, motile, non-spore formingrod shaped bacterium and it was designated as Pseudoxanthomonas strain RSA-23; it was found to possess broadspectrum of antimicrobial activity against pathogenic microorganisms. Furthermore, the most potent strain RSA-23was characterized by physiological, biochemical, and 16S ribosomal RNA gene sequencing. The 16S ribosomal RNAgene sequencing and analysis of phylogenetic tree showed 100% sequence similarity with Pseudoxanthomonas indica(KT204489). The methanol extract of Pseudoxanthomonas strain RSA-23 was analyzed through UV-spectroscopy andFourier transform infrared spectroscopy (FTIR). The UV-Vis. spectra revealed the presence of indole and the presenceof different functional groups, such as aldehydes, amines, and alkyl halides, were indicated by FTIR spectra.