Showing papers by "I. S. Bright Singh published in 2014"

Isolation and characterization of broad spectrum bacteriophages lytic to Vibrio harveyi from shrimp farms of Kerala, India.

Abstract: UNLABELLED Of 33 phages isolated from various shrimp farms in Kerala, India, six were segregated to have broad spectrum lytic efficiency towards 87 isolates of Vibrio harveyi with cross-infecting potential to a few other important aquaculture pathogens. They were further tested on beneficial aquaculture micro-organisms such as probiotics and nitrifying bacterial consortia and proved to be noninfective. Morphological characterization by transmission electron microscopy (TEM) and molecular characterization by RAPD and SDS-PAGE proved them distinct and positioned under Caudovirales belonging to Myoviridae and Siphoviridae. SIGNIFICANCE AND IMPACT OF THE STUDY In sustainable aquaculture, application of antibiotics is prohibited to manage vibriosis, including the one caused by Vibrio harveyi. In lieu of antibiotics, an eco-friendly alternative method, phage therapy, is recommended here. To facilitate the same, a set of six broad spectrum V. harveyi phages, as cocktail, has been constituted and characterized based on morphological traits and by employing molecular tools. These phages were also found to infect other aquaculture pathogens belonging to Vibrio and Aeromonas. Subsequent to in vivo trials, they can find application in shrimp hatcheries as prophylactics and therapeutics.

Potential application of β-1, 3 glucanase from an environmental isolate of Pseudomonas aeruginosa MCCB 123 in fungal DNA extraction

Abstract: Pseudomonas aeruginosa MCCB 123 was grown in a synthetic medium for β-1,3 glucanase production. From the culture filtrate, β-1,3 glucanase was purified with a molecular mass of 45 kDa. The enzyme was a metallozyme as its β-1,3 glucanase activity got inhibited by the metal chelator EDTA. Optimum pH and temperature for β-1,3 glucanase activity on laminarin was found to be 7 and 50 °C respectively. The MCCB 123 β-1,3 glucanase was found to have good lytic action on a wide range of fungal isolates, and hence its application in fungal DNA extraction was evaluated. β-1,3 glucanase purified from the culture supernatant of P. aeruginosa MCCB 123 could be used for the extraction of fungal DNA without the addition of any other reagents generally used. Optimum pH and temperature of enzyme for fungal DNA extraction was found to be 7 and 65 °C respectively. This is the first report on β-1,3 glucanase employed in fungal DNA extraction.

Nitrifi cation by stringed bed suspended bioreactors at different salinities and substrate concentrations

Abstract: Stringed Bed Suspended Bioreactor (SBSBR) is a fixed film bioreactor activated with indigenous nitrifying bacterial consortia under salinity regimes of 15 and 30 ppt for rapid nitrification in brackish water and marine aquaculture systems respectively. Compared to domestic wastewater; total ammonia nitrogen (TAN) is a limiting factor for nitrification in most aquaculture treatment systems. Therefore, the nitrification by SBSBRs was analyzed at TAN concentrations of 1, 2, 3 and 4 mg/L under salinities of 15 and 30 ppt for 12 hr. Percentage TAN removal was maximum when the total ammonia concentration was 1 mg/L. There was no significant difference in nitrification rates at different salinities whereas the rates differed significantly (P<0.01) with increasing TAN concentrations. Regression analysis showed that nitrification rates at both the salinities followed a linear increase with increasing TAN concentrations.

Evaluation of phytotoxicity of coir pith black liquor generated by oxidative delignification process to Oryza sativa L

Abstract: Coir pith is a polyphenol containing agroindustrial residue which causes land and water pollution. Research programs are advancing by utilising coir pith as a substrate for bio energy production, and oxidative delignificationwas reported as an effective pretreatmentmethod. Oxidative delignification process generates highly coloured ‘Coir pith Black Liquor’ (CBL) as effluent and its release to open environment poses pollution risks. Evaluation of toxicity of CBL is of significance for its safe disposal plans. In the present study, we investigated the phytotoxicity of CBL to a standard test species Oryza sativa. A 96 hour bioassay was conducted. Root length, shoot length, seed germination, Germination Index (GI), Seed Vigor Index (SVI) and Shoot toRoot ratio (S:R)were the parameters studied. Data acquisition was done with the help of image analysis software ‘Fiji’. Statistical analysis was carried out using ‘R’ software. The EC50 (Median Effective Concentration), the concentration at which 50% reduction in growth, compared to control, occurred was calculated for each parameter. The EC50s were converted into Toxic Units (TU) for comparison. All parameters studied were significantly affected by the CBL. The study revealed that CBL was acutely toxic to Oryza sativa. Root length and Germination Index (GI) were the most sensitive endpoints (TUs = 8.9 and 8.8 respectively) whereas seed germinationwas the least sensitive endpoint (TU = 1.73). Based on sensitivity, the parameters were arranged as : Root length=GI>Seedling length=SVI>Shoot length>Germination. The results points towards the necessity of further characterization of toxicants present in the CBL and treatment procedures to eliminate the toxicity.