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Kothamangalam, India

Selven S.,Cochin University of Science and Technology | Selven S.,Mar Athanasius College | Philip R.,Cochin University of Science and Technology
Aquaculture Research | Year: 2013

The effect of ambient salinity on the haemolymph variables of Fenneropenaeus indicus and its susceptibility to Vibrio harveyi infection under salinity stress has been studied. Adult shrimps were acclimated to 5‰ (hypo osmotic), 25‰ (iso osmotic) and 35‰ (hyper osmotic) salinity levels and the animals were injected with a mid logarithmic culture of V. harveyi at sub lethal level and haemolymph parameters were analysed. Haemolymph proteins, intracellular superoxide anion production, phenoloxidase (PO), alkaline phosphatase (ALP) and acid phosphatase (ACP) activity were found to be at elevated level both at 5‰ and 35‰ post challenge. The haematological responses showed a progressive increase (P < 0.05) up to post challenge day 5 (PCD 5) followed by a considerable decline at all salinities with the lowest being at 35‰. The alterations in the variables were higher in shrimps held at 5‰. However, the V. harveyi infection was severe in animals held at 35‰. The reduction in the parameters could be correlated with the decrease in survival rate of shrimps at 35‰ with a concurrent increase in V. harveyi at this salinity. Multiple regression analysis revealed that ACP (P < 0.001), haemocyte protein HCP (P < 0.001) and PO (P < 0.05) could explain 91% variability in the shrimp survival. These parameters may be used as effective shrimp health indicators. It is evident from the study that ambient salinity alters the haemolymph variables, modulates the virulence in V. harveyi and makes the shrimps more vulnerable to infection at higher salinity. The virulence of V. harveyi is increased at 35‰ salinity as being evidenced from the high mortality at this salinity. The study emphasizes the importance of salinity as an important environmental factor both in terms of host susceptibility and virulence of the pathogen. © 2012 Blackwell Publishing Ltd.

Subramanian S.,Cochin University of Science and Technology | Subramanian S.,Mar Athanasius College | Philip R.,Cochin University of Science and Technology
Aquaculture International | Year: 2013

Haematological alterations in Fenneropenaeus indicus fed marine yeast glucan-incorporated diet and challenged with white spot syndrome virus were analysed. Adult F. indicus 16.45 ± 2.12 g (mean ± SD) were reared in 25 ‰ sea water and allowed to acclimate for a period of 7 days. Diet was prepared incorporating glucan (0.2 %) extracted from marine yeast, Debaryomyces hansenii S169. The shrimps were reared on experimental diet for 28 days and then challenged with white spot syndrome virus through oral administration. Random sampling was done (n = 6 shrimps) on 1st, 15th and 28th day of the experiment and on post-challenge day 2 (PCD 2) and PCD 7 for haematological analysis. The immune parameters viz. plasma protein, total haemocyte count, phenoloxidase activity, superoxide anion production, alkaline phosphatase and acid phosphatase activities were estimated in the haemolymph. Superoxide dismutase, catalase, glutathione peroxidase, hydroperoxide, conjugated dienes and malondialdehyde concentrations in the haemolymph of shrimps were also analysed. Analysis of variance showed that there are significant differences (p < 0.05) in the immune and antioxidant parameters in different treatment groups of F. indicus. The shrimps fed glucan-incorporated diet showed higher survival rate with comparatively lower accumulation of lipid peroxidation products. Correlation coefficients showed that all haematological variables except hydroperoxides and conjugated dienes exhibited positive correlation with the survival rate. The immune variables and antioxidant parameters exhibited a greater degree of correlation with each other. When multiple regression of survival rate on all immune parameters was considered, the amount of variability explained was 93 % (R Square = 0.932). When significant regression coefficients among the immune parameters were taken into account, it was found that total haemocyte count (p < 0.001), phenoloxidase activity (p < 0.05), alkaline phosphatase activity (p < 0.05) and plasma protein concentration (p < 0.05) together are explaining 84 % (R 2 = 0.842) of the variability, indicating that these four parameters are mainly supporting the survival. The amount of variability explained by the antioxidant parameters was 94 % (R 2 = 0.938). When significant regression coefficients among the antioxidant parameters were taken into account, it was found that superoxide dismutase activity (p < 0.01) and catalase activity (p < 0.05) together are explaining 87.4 % (R 2 = 0.874) of the variability, indicating that these two antioxidants act as the major immune effectors supporting the survival in shrimps. © 2013 Springer Science+Business Media Dordrecht.

Kurian M.,Mar Athanasius College | Nair D.S.,Mar Athanasius College
Journal of Water Process Engineering | Year: 2015

An evaluation of heterogeneous Fenton behavior of nano nickel-zinc ferrite catalysts in the Wet Peroxide Oxidation for the degradation of 4-chlorophenol is presented. A series of spinel type NixZn1-xFe2O4 (x =0.0, 0.25, 0.5, 0.75, 1.0) catalysts were prepared by sol-gel auto combustion method and characterized by X-ray diffraction, Transmission Electron Microscopy, X-ray fluorescence and Fourier Transform Infra-Red spectroscopy. Fenton's reaction was performed over different compositions of nickel zinc ferrite catalysts under neutral conditions and the catalytic activities were studied. The yield of the reaction, based on Gas Chromatographic and Chemical Oxygen Demand (COD) parameters were very high and the experimental results indicated complete degradation of target pollutant with significant reduction of COD with all catalysts within 75min. Zinc substitution enhanced the catalytic activity of nickel ferrite and the un-substituted ZnFe2O4 degraded the target compound completely within 45min. Catalysts were found to be reusable and the extent of iron leaching, quantified by Atomic Absorption Spectroscopic studies was negligible after five consecutive cycles indicating the mechanism to be heterogeneous. Phase analysis of catalyst using XRD after the completion of each catalytic cycle confirmed the stability of the catalyst toward the Wet Peroxide Oxidation of 4-chlorophenol. © 2014 Elsevier Ltd.

Kurian M.,Mar Athanasius College | Kunjachan C.,Mar Athanasius College
Nano-Structures and Nano-Objects | Year: 2015

Cex Fe1-x O2/Cex Zr1-x O2 (x:0, 0.25, 0.5, 0.75, 1) prepared by coprecipitation method were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), N2 adsorption at -196 °C, Fourier transform Infra Red (FT-IR) spectroscopy, Fourier Transform Raman spectroscopy and thermal analysis (TG-DTA). XRD and TEM analyses reveal the presence of nanoparticles in all oxides beyond solid solution limit. The reduction in lattice parameter values of Ce-Zr/Fe mixed oxides compared to ceria can be attributed to the compositional changes along with particle growth since the ionic radius of Fe/Zr is smaller than that of Ce. Changes in the solid solution structure from cubic fluorite occur as a result of the crystallite growth of Fe2O3/ZrO2 particles on increased Fe/Zr content. Lattice strain measured by Williamson-Hall plot indicates an increase in lattice strain as a result of incorporation of Fe/Zr ions into the ceria lattice. The BET surface area and pore volume of synthesized composites are in the range of 30-10m2/g and 0.004-0.01cm3/g. Raman analysis reveals that iron incorporated ceria lattice have increased oxygen vacancy formation and gradual shrinkage of the unit cell. FT-IR spectra reveal the characteristic Ce-O stretching and crystalline water absorption of synthesized nanoparticles. Thermal analysis data shows these oxides to be thermally stable. © 2015 Elsevier B.V.

Kurian M.,Mar Athanasius College | Nair D.S.,Mar Athanasius College
Journal of Environmental Chemical Engineering | Year: 2014

Cobalt substituted zinc ferrite nanoparticles prepared by sol-gel auto combustion method are efficient catalysts for the wet peroxide oxidation of 4-chlorophenol. Complete degradation of 4-chlorophenol occurs within one hour with all catalysts under study. 90% of the target compound is removed with oxidant concentration as low as 1 ml. Varying the catalyst dosage, it is found that direct correlation between the amount of catalyst present and extent of degradation of 4-chlorophenol is observed, ruling out the heterogeneous- homogeneous mechanism. The catalysts are reusable and the activity of the catalysts remains almost the same after four successive runs. The extent of iron leaching is fairly low after five consecutive cycles indicating the mechanism to be heterogeneous. © 2013 Published by Elsevier Ltd.

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