Differences in the digestive biochemistry between the intertidal clam, Ruditapes decussatus, and the subtidal clam, Venerupis pullastra

Abstract

The present study was aimed to evaluate differences in physicochemical characteristics (pH and temperature optima) of the main digestive enzymes (amylase, cellulase, laminarinase, and protease) in two commercially important bivalves, the intertidal clam, Ruditapes decussatus, and the subtidal clam, Venerupis pullastra, as well to assess individual variability of such activities. The assays were performed on extracts obtained from the digestive glands and crystalline styles of individuals collected in the wild and laboratory-conditioned during 1 week. In both species, maximum activity for amylase and cellulase was measured at pH 6 and that of laminarinase at pH 5.5, while pH profiles of protease activity showed important differences between them. Temperature profiles also showed interspecific variations, mainly in laminarinase. Carbohydrase activities were comparatively much higher in R. decussatus and proteolytic activities in V. pullastra. The observed differences both in physicochemical characteristics and relative importance of digestive enzymes are discussed in relation to the amount and type of food available in their respective habitats.

Development of anin vitromodel to assess protein bioavailability in diets for common octopus (Octopus vulgaris)

“…Protease in extracts from PSG (which showed the greater activity of both salivary glands) showed maximum activity at alkaline pH; this could be related to the fact that secretion of the salivary glands is produced to carry on the initial hydrolysis of protein which takes place externally, in contact to surrounding sea water, which is neutral or slightly alkaline. In contrast, the most important activity detected in the HP was measured at an acid pH (between 4.0 and 5.0), this being in agreement to the optimal pH reported for protease activity in the digestive glands of other mollusc species (Ibarrola, Larretxea, Iglesias, Urrutia & Navarro ; Albentosa & Moyano ). This could be related to the fact that protein digestion in this zoological group still relies to a great extent on intracellular digestion performed by cathepsin‐type proteases in the digestive gland, showing those enzymes optimum pH ranges from 4–6.…”

Changes in enzymatic activity during early ­development of bay scallops Argopecten irradians and sea scallops Placopecten magellanicus

“…Digestive capacity may also differ between species with differing life histories or environmental adaptations (Albentosa & Moyano 2009). The sea scallop Placopecten magellanicus is restricted to cold waters (≤20°C; Naidu 1991) and growth rates are relatively slow, attaining a market size of 90 mm shell height (SH) in ~3 yr (Dadswell & Parsons 1991).…”

Digestive Enzyme Activity within Crystalline Style in Three Species of Bivalves

“…당면체가 아미노산과 탄수화 물 성분으로 구성되었다는 사실이 알려졌다 (Bailey and Worboys, 1960;Doyle, 1966;Albentosa and Moyano, 2009). 그러나 여러 저자들이 당면체의 효소활성에 대한 분석 을 진행하기는 했지만 (Horiuchi and Lane, 1966;Wojtowicz, 1972;Trainer and Tillinghast, 1982) …”

“…Crassostrea virginica, Geukensia demissa, Macoma balthica, M. mitchlli, Rangia cuneata에서는 amylase, cellulase, laminarinase 등 주로 탄수화물 분해효소들로 구성된다 (Brocka and Kennedy, 1992). 하지만 Cerastoderma edule (Ibarrola et al, 1998) 과 Ruditapaes decussatus 및 Venerupis pullastra 의 당면체는 탄수화물 분해효소와 protease로 구성된다 (Albentosa and Moyano, 2009). 당면체의 소화효소학적 기능에 관한 연구들은 Strombus gigas의 간췌장과 당면체에서 적정 온도와 pH에 따른 탄수화 물 분해효소의 활성 (Horiuchi and Lane, 1966),…”