Antifouling activity of marine epibiotic bacterium <i>Bacillus flexus</i> APGI isolated from Kanyakumari Coast, Tamilnadu, India

1396-1400In this study, an attempt has been made to explore the antifouling activity of newly isolated seaweed epibiotic bacterium Bacillus flexus APGI. Antimicrofouling activity of ethyl acetate extract of B. flexus APGI inferred that, it exhibited pronounced inhibitory zones against fouling bacterial strains (5 to 14 mm) with least minimal inhibitory concentration (MIC) ranged between 25 and 100 µg ml-1. Antimacrofouling activity results showed that, the MIC of ethyl acetate extract for complete inhibition of byssal thread production and attachment of mussel Perna indica was found to be 108 µg ml-1. Further, EC50 50 and 100% recovery of P. indica in toxicity assay propagated the non-toxic nature of the extract. Anticrustacean assay using Artemia salina larvae registered LC50 value of 835 µg ml-1. Analysis of chemical constituents suggested the presence of mid polar components such as alkaloids, coumarins and quinones in the extract. This study tends to indicate that, B. flexus APGI could be potentially explored for the development of new antifouling agents

RAPD analysis of dominant denitrifying bacterial species in the estuarine environment of south west coast of India

1696-1703An investigation was made on the Random amplification of polymorphic DNA (RAPD) analysis of dominant denitrifying bacterial species in an estuarine environment (Rajakkamangalam estuary) of South west coast of India. From the collected water samples, the dominant denitrifying bacterial populations such as Pseudomons aeruginosa and Bacillus cereus were identified. These dominant denitrifying bacterial species were further characterized by using RAPD-PCR analysis. The results indicated that the amplification of polymorphic DNA of the above strains was varied much with respect to the variation in sampling stations and seasons. Accordingly, the similarity index and homology coefficient (%) of the isolates were also varied much

Screening and partial purification of antifungal metabolite from <i style="mso-bidi-font-style:normal">Streptomyces rochei</i> MSA14: an isolate from marine mining soil of Southwest coast of India.

888-897A total of fourteen actinobacterial strains were isolated from the mining sediment of Manavalakurichi, Southeast coast of India. Primary screening results through agar well diffusion method revealed that 28.57% actinobacterial strains had in vitro antifungal activity. Most potent actinobacterial isolate MSA14 showed strongest inhibitory activity and was identified as Streptomyces rochei through morphological, physiological, biochemical and 16S rRNA gene sequence characteristics. Crude ethyl acetate extract of S. rochei exhibited wide spectrum antifungal activity which was ranged between 12 and 17 mm. Further evaluation of Minimum inhibitory concentration (MIC) and Minimum fungicidal concentration (MFC) showed the values ranged from 50 to 200 and 100 to 200 µg/ml, respectively. Partial purification of crude extract through TLC using various gradient solvent system recorded different spots of active principles with the respective Rf values between 0.22 and 0.90. TLC autobiography assay evidenced that, spot with the Rf value of 0.54 had promising antagonistic activity

Investigation on antibacterial, antifungal and cytotoxic properties of chosen mangroves

1769-1777In the present study antibacterial, antifungal and cytotoxic properties of organic solvent extracts of three mangroves viz. Avicennia marina, Acanthus ilicifolius and Excoecaria agallocha were evaluated. Results showed significant variation in bioactivity with respect to mangroves and solvents used for extraction. Antibacterial and antifungal activity of crude extracts revealed that, methanol extracts had wide spectrum antagonistic activity than chloroform and acetone extracts. Antagonistic activity exhibited by methanol extracts were in the following order: E. agallocha > A. marina > A. ilicifolius. Artemia cytotoxicity assay results inferred that, methanol extracts of E. agallocha, A. marina and A. ilicifolius recorded higher toxicity at lower concentration. Phytochemical analysis of crude extracts showed marked variation in its presence. Findings of the present study indicated that, the synergistic effect of active principles within the crude extracts were responsible for promising biological activity. Thus mangroves proved to be a good source of antimicrobial and cytotoxic agent