P C Thomas

Molecular cloning, characterization and expression analysis of F-type lectin from pearl oyster Pinctada fucata

F-type lectin is an important type of pattern recognition receptor that can recognize and bind carbohydrate moieties on the surface of potential pathogens through its carbohydrate recognition domains (CRDs). This paper reports the cloning of an F-type lectin (designated as pfF-type lectin) from the pearl oyster (Pinctada fucata) using rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA of this pfF-type lectin contains an open reading frame (ORF) of 588 bp coding for196 amino acids. A signal peptide at the N-terminus of the deduced polypeptide was predicted by the signal P program and the cleavage site is located between the positions of Gly(19)and Tyr(20). Conserved domain search at NCBI revealed the pfF-type lectin domain extends from Lys(55)to Val(192). Semi-quantitative analysis in adult tissues showed that the pfF-type lectin mRNA was abundantly expressed in haemocytes and gill and rarely expressed in other tissues tested. After challenge with lipopolysaccharide (LPS), expression of pfF-type lectin mRNA in haemocytes was increased, reaching the highest level at 4 h, then dropping to basal levels at 36 h. These results suggest that F-type lectin play a critical role in the innate immune system of the pearl oyster P. fucata.

Quality of Six Indian Populations of Artemia franciscana for Larval Finfish Culture

We explored the nutritional value to larval finfish of Artemia populations from various geographical locations in India. Cyst and nauplii biometry, hatching percentage, and nutrient content were measured and compared with commercially available San Francisco Bay Brand A. franciscana (SFB). Marakkanam population possessed the smallest cyst and nauplii, followed by SFB. The Nagercoil, Marakkanam, and Mithapur populations had significantly higher carotenoid content in cyst, nauplii, and adult stages compared to SFB. The essential polyunsaturated fatty acid 22:6n-3 was higher in nauplii of the Marakkanam, Nagercoil, Vedaranyam, and Tuticorin populations compared to SFB. Often limiting amino acids such as threonine, leucine, arginine, lysine, methionine, and histidine were observed in higher levels in the nauplii stage than in the cyst and adult stages of Artemia. The Marakkanam and Mithapur populations appeared promising as substitutes for expensive imported Artemia with respect to nutrient and biometric quality indicators.