NOPR Collection:

Virulence of Vibrio harveyi possessing a transferable chloramphenicol resistance determinant to larvae of Indian white shrimp Fenneropenaeus indicus (Decapoda)

2006-09-01T00:00:00Z

Title: Virulence of Vibrio harveyi possessing a transferable chloramphenicol resistance determinant to larvae of Indian white shrimp Fenneropenaeus indicus (Decapoda) Authors: Abraham, T. Jawahar Abstract: The virulence of luminous Vibrio harveyi possessing a transferable chloramphenicol-resistance determinant to Indian white shrimp, Fenneropenaeus indicus larvae was studied. The V. harveyi strains isolated from luminous F. indicus larvae produced extracellular virulence factors such as haemolysin, chitinase, proteinase, lipase and phospholipase were resistant to at least four of six antibiotics tested. The chloramphenicol-resistance determinant was transferred from V. harveyi to Escherichia coli at frequencies of 6.69  10⁻⁴ - 4.27  10⁻³. The concentration of V. harveyi cells capable of causing 50% mortality differed significantly (P<0.05) and the 72 h LD₅₀ values ranged between 273 and 3,040 cells/ml. The chloramphenicol-resistant strains were more virulent to shrimp larvae compared to chloramphenicol-sensitive strain. Prevalence of highly virulent V. harveyi strains harbouring a transferable chloramphenicol-resistance determinant together with other extracellular virulence factors may hamper the hatchery production of penaeid shrimp larvae. Page(s): 275-278

Superior quality agar from red alga Gelidiella acerosa (Rhodophyta, Gelidiales) from Gujarat coast of India: An evaluation

2006-09-01T00:00:00Z

Title: Superior quality agar from red alga Gelidiella acerosa (Rhodophyta, Gelidiales) from Gujarat coast of India: An evaluation Authors: Prasad, Kamalesh; Goswami, A.M; Meena, Ramavatar; Ramavat, B.K.; Ghosh, Pushpito K.; Siddhanta, A.K. Abstract: Physicochemical and rheological properties of agars extracted from 20 samples of Gelidiella acerosa collected from Gujarat coast in various seasons have been evaluated. The agar yields varied significantly (8.5–40.4%). The gel strength values were in the range of 200-700 g cm⁻² (1.5% gel at 20ºC) having gelling temperatures 36-41ºC. It was observed that agar obtained from Gelidiella acerosa of Okha, in almost all seasons has superior physicochemical and rheological properties than the rest of the samples. The 3,6-anhydrogalactose (3,6-AG) and sulphate content too varied significantly among the agar of each place. It was observed that the better quality agar has relatively lower sulphate and higher 3,6-anhydrogalactose contents. Therefore, Gelidiella acerosa of Okha can be used as a good source of agar. Rheological data of the best agar of the lot were also in good agreement with the other physicochemical data e.g., high gel strength agar showed higher G' value and vice versa. Page(s): 268-274

Biosorption studies for removal of chromium using immobilized marine alga Isochrysis galbana

2006-09-01T00:00:00Z

Title: Biosorption studies for removal of chromium using immobilized marine alga Isochrysis galbana Authors: Kumar, K. Kishore; Prasad, M. Krishna; Sarma, G.V.S.; Murthy, Ch.V.R. Abstract: A new biosorbent material marine micro alga Isochrysis galbana, from marine sources Bay of Bengal, was immobilized and used as an adsorbent for removal of chromium. It was found that the increase in aqueous metal concentration increased metal uptake within the range of present study. The presence of acid decreased metal uptake probably due to the preferential adsorption of hydrogen ion compared to chromium ion. The immobilized calcium alginate beads were also found to adsorb chromium in absence of biomass as well and presence of biomass increased the metal adsorption by 3-4 fold. This immobilized biomass was very effective for the removal of chromium. Isochrysis galbana was found to adsorb chromium more strongly when compared to another marine micro alga, Chaetoceros calcitrans, probably due to presence of polysilicate layers over Chaetoceros cells and also due to larger size of Chaetoceros cells. Equilibrium distribution data were best correlated by Freundlich type of equation for the range of experimental parameters covered in the present study. An empirical equation was proposed to estimate the equilibrium metal concentration in the immobilized algal beads (CS) as a function of pH and aqueous metal concentration (CA). Page(s): 263-267

A stochastic model to analyse pelagic fishery resource dominance along the Karnataka coast (west coast of India)

2006-09-01T00:00:00Z

Title: A stochastic model to analyse pelagic fishery resource dominance along the Karnataka coast (west coast of India) Authors: Kuriakose, Somy; Mini, K.G. Abstract: Stochastic models are appropriate for the study of dynamics of fishery and prominent among them are Markov chain models. In this study, the dynamics of the pelagic fishery resource assemblage along the Karnataka coast is analyzed with reference to the change in resource composition and relative dominance using Markov chain. The transition probabilities of the species dominance with respect to four dominant groups namely oil sardine, Indian mackerel, carangids and whitebaits have been estimated. From the higher order transition probabilities it is clear that, if oil sardine is dominant in the fishery now, the probability that it continues to be the dominant group in the next year is 0.4875 and in case of Indian mackerel, the probability that it will dominate in the next year is only 0.3834. It is also observed that in the long run the pelagic fish assemblage is more likely to be dominated by oil sardine than Indian mackerel. Page(s): 257-262