Characterization and production of polyclonal antisera against pangasius (Pangasianodon hypophthalmus) serum immunoglobulin IgM derived from DEAE cellulose based ion exchange chromatography

Pangasius (Pangasianodon hypophthalmus) is a commercially important candidate species in freshwater aquaculture and it is important to understand the immune system of pangasius against infectious disease. The present study was aimed at the purification, characterization and quantification of serum IgM in pangasius (P. hypophthalmus). Serum IgM was purified by diethylaminoethyl (DEAE) cellulose based ion exchange chromatography. The molecular weight of native immunoglobulin was found to be 798 kDa. Heavy (H) and light chains were found to possess molecular weight of 70.1 and 26 kDa respectively. A 248 bp segment of IgM H chain gene of pangasius was amplified and sequenced (partial). The antisera raised against pangasius immunoglobulin cross‐reacted with the immunoglobulin H chain of catfish such as Clarias gariepinus and Clarias batrachus, but not with their light chain indicating epitope sharing among IgM H chains in these catfish. The produced polyclonal antisera were used to develop an enzyme linked immuosorbent assay to quantify IgM levels in pangasius. In conclusion, the present study provides its future implications for epidemiology and immunology studies in pangasius.     

Dynamics and Nutrient Release Pattern of Silica Sources in a Typical Entisol of Tropical Humid Region of Kerala

Silicon is considered as a beneficial element for crop nutrition especially for monocots. In order to study the effect of addition of different silica sources on the nutrient release pattern from an Entisol, a laboratory incubation study was conducted with three silica sources viz., sodium silicate, calcium silicate, and potassium silicate each @ 200 ppm and 400 ppm per kilo gram soil. The positive effect of addition of silicates was obvious on soil reaction, available Si, P, K, Ca, and Mg. Release of plant available silicon was the highest at 60th day after incubation (DAI) with potassium silicate @ 400 ppm per kg soil. Sodium silicate @ 200 ppm resulted in the highest exchangeable magnesium concentration at 45th DAI. The result of the study implies the positive influence of silicates on soil acidity as well as on enhancing the availability of phosphorus, potassium, calcium, and magnesium in an Entisol.