An actin gene (CfACT1) was cloned by using RT-PCR, 3’and 5’RACE from hemocytes of the sea scallop Chlamys farreri. The full length of the transcript is 1 535 bp, which contains a long 3’ un-translated region of 436bp and 59bp of a 5’ un-translated sequence. The open reading frame encodes a polypeptide of 376 amino acids. Sequence comparisons indicated that CfACT1 is more closely related to vertebrate cytoplasmic actins than muscle types. Phylogenetic analysis showed that molluscan actins could be generally divided into two categories: muscle and cytoplasmic, although both are similar to vertebrate cytoplasmic actins. It was also inferred that different isotypes existed in muscle or cytoplasma in mollusks. The genomic sequence of CfACT1 was cloned and sequenced. Only one intron was detected: it was located between codons 42 and 43 and different from vertebrate actin genes.
Biodeposition method, a recently developed method used in studies on physio-ecological characteristics of bivalval mollusks, including clearance rate (CR), ingestion rate (IR), absorption efficiency (AE) and energy budget, is reviewed in this paper. The method estimates feeding and absorption rates through measurements of suspended particles and biodeposit production. The main assumption of this method is that ingested particulate inorganic matter can be used as an inert tracer of feeding and digestive processes. The method is based on feeding responses that are integrated over long time scales, reducing the variability on the measurements affecting growth parameters associated to instantaneous responses.
