Ontogeny of α-Amylase Gene Expression in Sea Bass Larvae (Lates calcarifer)

Abstract

The enzymatic activities of alpha-amylase and its corresponding messenger RNA levels in developing sea bass (Lates calcarifer) larvae were studied from hatching until 27 days post hatching (dph). An increasing activity of amylase enzyme was measured until 5 dph, and the activity gradually decreased thereafter and reached a constant level by 12 dph. To achieve a better understanding of the molecular mechanisms underlying amylase expression, we have cloned and sequenced a 318-bp fragment of alpha-amylase complementary DNA. Based on this sequence, a real-time reverse transcriptase polymerase chain reaction technique to monitor the changes in the mRNA levels in the larvae was developed. A correlation between enzymatic activity and mRNA level of alpha-amylase could be demonstrated during the early development of sea bass larvae. This suggests that the changes in alpha-amylase are controlled at least at the transcriptional level during early larval development of sea bass.

Ontogenetic development of digestive enzymes in Sobaity sea bream Sparidentex hasta larvae under culture condition

“…Although carbohydrate content is reduced in zooplanktonic prey (Dhont and Van Stappen, 2003), α-amylase has been found in ontogenetic development of digestive enzymes in carnivorous fish larvae (Martínez et al, 1999;Ribeiro et al, 1999;Zambonino-Infante and Cahu, 2001). Our findings further support the idea of genetically programmed and non stimulus-dependent secretion of amylase during early larval stage (Ma et al, 2005;Zambonino-Infante and Cahu, 2001), also a transcriptional regulation of the amylase expression in the subsequent days after hatching (Douglas et al, 2000;Ma et al, 2001). Meanwhile, the dietary level of the amylase substrate in micro diet used, might increase the late individual activity of this enzyme during weaning period (Chen et al, 2006;Ma et al, 2005).…”

Effects of constant light on haematological parameters of cultured rainbow trout (Oncorhynchus mykiss) in the Southern Hemisphere

“…The date of the decline of these pancreatic enzymes depended on the species: around the third week of life in D. labrax (Zambonino Infante and Cahu 1994), and S. ocellatus (Buchet et al 2000), the 10th day after hatching in S. senegalensis (Martinez et al 1999;Ribeiro et al 1999), and P. californicus (present study), and the 5th day after hatching in L. calcarifer (Ma et al 2001). The above-mentioned decline in specific enzyme activity of amylase, trypsin and chymotrypsin during larval ontogeny can be mainly explained by the normal increase of tissue proteins in growing larvae, which reflects anatomical and physiological changes in fish larvae, and does not correspond to a lowering in the amount of digestive enzymes or dietary shifts (Zambonino Infante and Cahu 2001).…”

Ontogenetic changes in digestive enzyme activities and the amino acid profile of starry flounder Platichthys stellatus

“…This change suggests a natural predisposition of young larvae to use carbohydrate (Krogdahl and Sunby, 1999). Several authors have reported that amylase expression is regulated at the transcriptional level and that the low mRNA level found in older larvae results in a decline in amylase activity (Douglas et al, 2000;Ma et al, 2001). The change in nutrient source from yolk (internal glycogen) to an external diet (protein) may be responsible for this pattern.…”