Phytochemical and Antimicrobial Analysis of Callus Extracts of Biophytum sensitivum (Linn) DC.

Aims: In vitro studies are highly instrumental in selecting a drug for a particular disease and also in getting the preliminary evidence to proceed for further In vivo pharmacological research. Hence, the study is designed to screen and identify the therapeutic suitability of this plant extract for the treatment of a particular disease. And to find out the presence of phytochemicals and antimicrobial activity of leaf callus cultures of Biophytum sensitivum Linn. Place and Duration of Study: Department of Botany and Microbiology, Acharya Nagarjuna University, Nagarjuna Nagar, Guntur 522510, India during June 2010 to Dec 2010. Methodology: Here we induced the callus from the leaf explants of this species on Murashige and Skoog basal medium supplemented with various concentrations of BA and NAA. BA 1.0 mg/l with NAA 1.0mg/l is the best concentration for optimal results. The callus was extracted sequentially with hexane, chloroform, ethyl acetate and methanol for 24h by using Soxhlet apparatus. These extracts were used to investigate the presence of phytochemicals which was performed according to the Aiyelaagbe and Osamudiamen [29] and Egwaikhide et al. [30] methods. The mean values were statistically analyzed with the MINITAB 14 by the general one way (un stacked) analysis of variance (ANOVA) to find out the most effective extracts Results: The qualitative phytochemical analysis of various solvent extracts showed the presence of phytochemicals viz., Terpenoids, phenols, flavonoids, saponins, quinones and phenols. All the extracts except hexane showed highest zone of inhibition against gram positive and gram negative bacteria (4.46-22.9mm) as well as fungi (7.64-144.4mm) by agar well diffusion method at 100ppm concentrations. The results of present study indicate that the callus of this plant is a potential source of antimicrobial agents and drugs and need to be investigated further. Conclusion: From the present study, it is evident that, the antibacterial active constituent of Biophytum sensitivum is having a constant expression pattern over different pathogens. This plant leaf callus can be further subjected to enhancement and isolation of the therapeutic antimicrobials and carry out further pharmacological evaluation.

Optimization of the Cultural Parameters for Improved Production of Antimicrobial Metabolites by Streptomyces gulbargensis DAS 131.

Aims: To investigate the influence of appropriate culture medium by optimizing the cultural conditions affecting the growth and bioactive metabolite production by Streptomyces gulbargensis DAS 131 under submerged culture conditions in order to reduce the cost of fermentation process to improve the formation of antimicrobial compounds. Place and Duration of Study: Department of Botany and Microbiology, January 2012 to May 2012. Methodology: The impact of environmental parameters such as incubation period, pH, temperature and salt concentration and effect of various nutrients such as carbon and nitrogen sources and minerals on the antimicrobial metabolite production by Streptomyces gulbargensis DAS 131 was evaluated by employing agar well diffusion assay. Growth was measured in the form of dry mycelial weight. Results: The optimum pH and temperature for bioactive metabolite production were 7 and 35°C respectively. Highest antimicrobial metabolite production was found when the strain was inoculated into the medium amended with glucose at the concentration of 2%, soya peptone at the rate of 1% and NaCl at the concentration of 5% and incubated for six days under shaking conditions. The metabolites showed good antimicrobial activity against Gram positive and Gram negative bacteria, as well as unicellular and multicellular fungi. Conclusion: S. gulbargensis DAS 131 isolated from the semi-arid soils of Gulbarga, Northern Karnataka province, India exhibited broad spectrum antimicrobial activity. It was found that the antimicrobial metabolite production by the strain was positively influenced by carbohydrates, nitrogen sources and minerals.

Exploration of Actinobacteria from Mangrove Ecosystems of Nizampatnam and Coringa for Antimicrobial Compounds and Industrial Enzymes.

Aim: A study was made to examine the kinship between the seasonal distribution of actinobacteria and the physico-chemical properties of the mangrove sediments of Nizampatnam and Coringa located along the South East coast of Andhra Pradesh, India. Place and Duration of Study: Department of Botany and Microbiology, between April 2010 to February 2011. Methodology: Seasonal enumeration of actinobacteria from two different stations 1 (Nizampatnam) and 2 (Coringa) accorded by four different pre-treatments of soil sediments followed by plating onto three different media showed high incidence of actinobacteria in the month of February and least in December. Pretreatment with calcium carbonate and plating on starch casein agar yielded maximum number of actinobacteria. The strains were identified based on the morphological characteristics such as aerial mycelium, substrate mycelium, diffusible pigments and micro morphological features. Results: The present investigation revealed that majority of the mangrove actinobacteria 69%) belongs to Streptomyces spp. Among the 55 isolates screened for antimicrobial compounds, 28 were found to be potential producers. The isolates could also produce commercially important enzymes such as L-asparaginase, cellulase and amylase. In addition the statistical study also revealed that positive correlation between the distribution of the actinomycetes and influence of physico-chemical parameters and the organic matter of the soil. Conclusion: Our study revealed that the unexplored regions like Nizampatnam and Coringa mangrove ecosystems are proved as potential sites for antimicrobial and industrial enzyme producing actinobacteria.

Isolation, Identification and Molecular Characterization of Rare Actinomycetes from Mangrove Ecosystem of Nizampatnam

Aims: Isolate and characterize the antimicrobial actinomycetes from sediments of Mangrove ecosystems of Nizampatnam located in the south coastal region of Andhra Pradesh, India. Methodology and Results: The Mangrove soil samples were collected, pre-treated and plated on asparagine-glucose agar medium. Identification of the strain was carried out by employing the polyphasic taxonomical studies including the 16S rRNA sequence based analysis. Phylogenetic tree was constructed using the Molecular Evolutionary Genetic Analysis (MEGA) version 5. The potent bioactive metabolite strain was isolated and designated as VUK-10. Further polyphasic studies revealed that the Isolate VUK-10 belongs to the genera Pseudonocardia. Phylogenetic analysis of 16S rRNA sequencing studies revealed that the strain is closely related to Pseudonocardia endophytica and the bioactive metabolites produced by the isolate inhibited Gram positive, Gram negative and Fungi. Conclusion, significance and impact of study: The isolation, characterization of the rare actinomycetes from the mangrove ecosystem will be useful for the discovery of the novel bioactive metabolites that are effective against wide range of pathogens.

Chitinase production by Streptomyces sp. ANU 6277

Chitinase production by a terrestrial Streptomyces sp. ANU 6277 was studied under sub-merged fermentation. Chitinase production started after 24 h of incubation and reached maximum levels after 60 h of cultivation. A high level of chitinase activity was observed in the culture medium with pH 6 at 35ºC. Culture medium amended with 1 percent chitin was found to be suitable for maximum production of chitinase. An optimum concentration of colloidal chitin for chitinase production was determined. Studies on the influence of additional carbon and nitrogen sources on chitinase production revealed that starch and yeast extract served as good carbon and nitrogen sources to enhance chitinase yield.Chitinase was purified from crude enzyme extract by single step gel filtration by Sephadex G-100. Purified chitinase of the strain exhibited a distinct protein band near 45 kDa by means of SDS-PAGE.