Digestive carbohydrases from the hepatopancreas of two Antarctic euphausiid species (Euphausia superba and E. crystallorophias)

McConville, Malcolm J.; Ikeda, Tsutomu; Bacic, Antony; Clarke, AE

doi:10.1007/bf00428561

Cited by 21 publications

(21 citation statements)

References 38 publications

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“…McConville et al (1986) reported similar results for 1,3-b-D-glucanase in krill. Hassett and Landry (1982) suggested that high activities of digestive enzymes at low food concentrations are an adaptation to a patchy and thus unpredictable food supply.…”

Section: Discussionsupporting

confidence: 60%

“…Mayzaud and Poulet 1978;Mayzaud and Mayzaud 1981;Hassett and Landry 1982;Tande and Slagstad 1982) or the midgut gland only (McConville et al 1986). The complexity of the digestion process and interactions between midgut gland and the stomach can be explained only when both organs are investigated separately (Buchholz 1989).…”

Section: Discussionmentioning

confidence: 99%

“…In addition to several glucanases and proteases (Mayzaud et al 1985;McConville et al 1986), high activities of endo-chitinase (poly-b-1,4-(2-acetamido-2-deoxy)-D-glucosid-glucanohydrolase) and N-acetyl-b-D-glucosaminidase (here NAGase) have been found in the digestive tract of krill (Buchholz 1989). Both enzymes are also present in the integument, where they show moult-related patterns of activity .…”

Section: Introductionmentioning

confidence: 99%

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A laboratory study on digestive processes in the Antarctic krill, Euphausia superba , with special regard to chitinolytic enzymes

Saborowski

Búchholz

1999

Polar Biology

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Feeding experiments of 9, 14 and 20 days duration were carried out on the Antarctic krill, Euphausia superba. Two groups were fed with the chitinous diatom Cyclotella cryptica and the non-chitinous green algae Dunaliella bioculata, respectively. A control group remained unfed. The time courses of the activities of endo-and exochitinase in the stomach and the midgut gland were compared with those of the digestive enzymes protease, cellulase (1,4-b-D-glucanase) and laminarinase (1,3-b-D-glucanase). Speci®c activities of all enzymes were higher in the stomach than in the midgut gland. Characteristic time courses of activity were evident after 4 days. In starved animals, enzyme activities decreased to a minimum after 4 days and recovered within 14 days to initial values. In the stomach, the activities of endo-and exochitinase increased when krill were fed on Cyclotella. For animals fed with Dunaliella, activities stayed constant or decreased slightly. The results con®rm chitinases as digestive enzymes and, therefore, the capability of krill to utilize various food sources.

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Section: Discussionsupporting

confidence: 60%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A laboratory study on digestive processes in the Antarctic krill, Euphausia superba , with special regard to chitinolytic enzymes

Saborowski

Búchholz

1999

Polar Biology

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“…We limited the number of enzymes studied to two extracellular enzymes, laminarinase and proteinase. The first catalyses the degradation of 1,3-beta-D-glucosidic linkages of laminarin, a major compound in phytoplankton species (McConville et al 1986;Haug and Myklestad 1973), and the ability to digest protein-rich diets is represented by the latter.…”

Section: Digestive Enzyme Activitymentioning

confidence: 99%

“…McConville et al (1986) reported that the glucanase activity was negatively related to food availability and roughly doubled after starvation, while Garrison et al (1986) found high levels of digestive enzymes in late winter krill. These findings, like our own, are suggestive of an increase in enzyme concentrations at low food levels.…”

Section: Digestive Enzyme Activitymentioning

confidence: 99%

Seasonal differences in citrate synthase and digestive enzyme activity in larval and postlarval antarctic krill, Euphausia superba

et al. 2002

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Antarctic krill maintain large population sizes despite dramatic seasonal fluctuations in food availability, but the mechanisms for this are still debated. The aim of this study was to compare seasonal differences in enzyme activity and respiration rates of larval and postlarval krill to provide insights into their overwintering strategies. Respiration rates, activity of the metabolic enzyme citrate synthase (CS), and those of the digestive enzymes laminarinase and total proteinase were measured in austral summer west of the Antarctic Peninsula, and in autumn in the southwestern Lazarev Sea. The 100-fold difference in chlorophyll a concentrations between the two studies is representative of the classic transition from a summer bloom to sparse winter conditions. Correspondingly, adult krill showed reduced respiration rates and CS activity in autumn. However, their digestive enzyme activity was significantly higher, suggesting more efficient assimilation of food at low food levels. Similar-sized larvae showed no summer-autumn differences in respiration rates and enzyme activity, supporting suggestions that they need to feed and grow year-round. However, trends in enzymatic activity varied between the larval stages measured, implying ontogenetic changes in body structure and function.

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Alpha-glucosidase from the hepatopancreas of the shrimp,Penaus vannamei (Crustacea-Decapoda)

Chevalier

Wormhoudt

1998

J. Exp. Zool.

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Digestive carbohydrases from the hepatopancreas of two Antarctic euphausiid species (Euphausia superba and E. crystallorophias)

Cited by 21 publications

References 38 publications

A laboratory study on digestive processes in the Antarctic krill, Euphausia superba , with special regard to chitinolytic enzymes

A laboratory study on digestive processes in the Antarctic krill, Euphausia superba , with special regard to chitinolytic enzymes

Seasonal differences in citrate synthase and digestive enzyme activity in larval and postlarval antarctic krill, Euphausia superba

Alpha-glucosidase from the hepatopancreas of the shrimp,Penaus vannamei (Crustacea-Decapoda)

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