Functional Aspects of Nutrition and Digestion

Dall, W.; Moriarty, David

doi:10.1016/b978-0-12-106405-1.50015-1

Cited by 184 publications

(126 citation statements)

References 181 publications

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“…By contraction of the muscle ®bres these enzymes are pumped actively from the tubules through the funnel into the pylorus. This description is also in close accordance with detailed investigations by Powell (1974) on thalassinid crustaceans (see also Dall and Moriarty 1983;Icely and Nott 1992). While feeding, digestion proceeds as described above.…”

Section: Discussionsupporting

confidence: 75%

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: 75%

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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“…Crustaceans occupy a huge variety of ecological niches. In re-sponse to environmental factors they have developed highly specialized biochemical adaptations which are particularly reflected by the immeasurable diversity of digestive enzymes [2][3][4][5][6]. The detailed function of digestive enzymes in crustaceans and particularly their synergetic interplay is still poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Stability and effects of organic solvents on endopeptidases from the gastric fluid of the marine crab Cancer pagurus

Saborowski

Sahling

Toro³

et al. 2004

Journal of Molecular Catalysis B: Enzymatic

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Activities of proteolytic enzymes, represented by azocasein digestion (total protease), trypsin, and chymotrypsin from the gastric fluid of the marine crab, Cancer pagurus, were evaluated for operational parameters like pH-optimum, thermal stability, and effectors such as metal ions and organic solvents. Total protease activity was 98.5 ± 4.3 E 366 min −1 ml −1 . Trypsin and chymotrypsin activities amounted to 14.7 ± 1.5 U ml −1 and 197 ± 59 U ml −1 , respectively. The maximum activity of total protease appeared at pH 5-7, that of trypsin at pH 7-9, and that of chymotrypsin at pH 6.5-7. Trypsin and chymotrypsin activities were slightly activated by Ca 2+ , but were drastically reduced by Zn 2+ . In the presence of 2-propanol, trypsin activity was enhanced 8-fold at 30• C. Highest amplification of activity of up to 30-fold, however, appeared below 12• C. The effects of ethanol and acetone were less distinct. These caused a 2.5-fold increase of activity. Methanol was the least activating solvent.Activities of all enzymes remained stable for up to 127 days at 5• C, keeping up to 70% of the initial activity. When stored at 25• C for 120 days, total protease decreased to about 40% and trypsin and chymotrypsin activities kept more than 60% of initial activity. Zymograms showed five major and several minor proteolytic bands with apparent molecular weight of 20-45 kDa. After long-term storage at room temperature, the major bands remained active, while some bands with minor activity disappeared. This proteolytic enzyme preparation from the gastric fluid of crab seems suitable for biotechnological application at neutral pH and in the presence of organic solvents.

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“…He incorrectly concluded that these glands produced digestive enzymes. Their function is more likely lubricative, since secretion of enzymes in crustaceans is limited to the midgut (Dall and Moriarty, 1983).…”

Section: Digestive Systemmentioning

confidence: 99%

The sensory mediation of symbiosis between hyperiid amphipods and salps

Diebel¹

1988

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Functional Aspects of Nutrition and Digestion

Cited by 184 publications

References 181 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

Stability and effects of organic solvents on endopeptidases from the gastric fluid of the marine crab Cancer pagurus

The sensory mediation of symbiosis between hyperiid amphipods and salps

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