Glycosidases in the american oyster, Crassostreavirginica Gmelin, digestive tract

Mayasich, Sally A.; Smucker, Richard A.

doi:10.1016/0022-0981(86)90090-0

Cited by 14 publications

(2 citation statements)

References 11 publications

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“…In a series of feeding experiments, particulate 14Clignocellulosic material was either introduced directly by syringe into the stomach of oysters (Newel1 & Langdon 1986) or oysters were allowed to feed on a suspension of the material in flow-through chambers (Crosby et al 1989). Despite the presence of extracellular p-1, 4-glucanase and reported intracellular P-glucosidase activities (Mayasich & Smucker 1986), oysters absorbed 14C from ingested lignocellulosic material with efficiencies of only 1.3 O/O * 0.6 % (n = 11) (syringe-fed oysters; Newel1 & Langdon 1986) and 2.7 % f 1.8 % (n = 20) (naturally fed oysters; Crosby et al 1989). On the basis of estimates given in Table 1, cellulosic carbon would only contribute 0.7 % of the summer metabolic carbon requirements of oysters inhabiting Canary Creek.…”

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confidence: 99%

Utilization of detritus and bacteria as food sources by two bivalve suspension-feeders, the oyster Crassostrea virginica and the mussel Geukensia demissa

Langdon¹,

Newell²

1989

Mar. Ecol. Prog. Ser.

214

111

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The concentration and composition of suspended particulate food available to estuarine suspension-feeding bivalve molluscs varies temporarily and spatially. Non-algal food sources may be important to suspension-feeders when algal concentrations are seasonally low or where there are high concentrations of suspended detrital material and bacteria, as found withln marshes. We carried out a series of laboratory experiments and field measurements to determine to what extent 2 common estuarine bivalve molluscs, the oyster Crassostrea virgin~ca and the ribbed mussel Geukensia demissa, could utilize cellulose and bacteria from Canary Creek marsh. Delaware, USA. Endogenously produced extracellular cellulases of the oyster depolymerized ingested cellulose to soluble oligomers. Subsequent intracellular cleavage of the oligomers to glucose was limited. The oyster absorbed carbon from refractory cellulosic material with an efficiency of only 3 %. In contrast, the ribbed mussel absorbed carbon from the same cellulosic material with an efficiency of 9 % and thls increased to 14 % if mussels were subjected to a 6 h exposure/6 h submergence cycle, a typical exposure regime for this intertidal species. We estimated that suspended cellulosic carbon in Canary Creek marsh during summer could supply 0.7 O/O and 8.6 % of the respiratory carbon requirements of subtidal oysters and intertidal mussels, respectively. In laboratory feeding experiments, colonization of refractory cellulosic food material by cellulolytic bacteria isolated from the marsh resulted in the oyster indirectly assimilating cellulosic carbon with an efficiency of 10 %. The oyster was able to filter free, unattached bacteria from suspension with an efficiency of only 5.0 %, compared with an efficiency of 15.8 % for the ribbed mussel. We estimated that both unattached and attached bacteria combined in Canary Creek marsh during summer provide only 5.5 % of the oysters' metabolic carbon requirements but could provide 31.0 % of an intertidal mussel's metabolic carbon requirements. Experiments with 1 5~ labelled bacteria indicated that attached bacteria associated with the breakdown of cellulosic material could mediate the flow of dissolved inorganic nitrogen from seawater to the oyster We estimated that unattached and attached bacteria in Canary Creek marsh during summer could contribute 26.7 % and 70.6 % of the metabolic nitrogen requirements of subtidal oysters and intertidal mussels, respectively. These results indicate that in thls marsh, utilization of bacteria as a food source could make a significant contribution during the summer to the nitrogen requirements of the oyster and to the carbon and nitrogen requirements of the mussel. However, cellulosic detritus and bacteria do not appear to fully meet the requirements of these bivalve species for carbon and nitrogen and utilization of other food sources is required, such as phytoplankton, nanozooplankton or non-cellulosic particulate and dissolved organic matter O Inter-Research/

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confidence: 99%

Utilization of detritus and bacteria as food sources by two bivalve suspension-feeders, the oyster Crassostrea virginica and the mussel Geukensia demissa

Langdon¹,

Newell²

1989

Mar. Ecol. Prog. Ser.

214

111

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“…Koopmans (1970) found that style extracts from the bivalve Cardium edule only weakly converted cotton to reducing sugars, compared with breakdown of reprecipitated cellulose or carboxymethyl cellulose. The presence of P-l,4-glucanase and P-glucosidase activities has been demonstrated in many bivalve species (Kristensen 1972, Wojtowicz 1972, Mathers 1973, Morton 1983, Lucas & Newel1 1984, Mayasich & Smucker 1986.…”

Section: Introductionmentioning

confidence: 99%

Digestion and absorption of refractory carbon from the plant Spartina alterniflora by the oyster Crassosfrea virginica

Newell¹,

Langdon²

1986

Mar. Ecol. Prog. Ser.

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The vascular plant Spartina alterniflora Loisel., grown in an atmosphere containing '"CO2, was chem~cally treated to produce a lignocellulosic, crude f~b e r material containing 0 1 ' 10 lipid, no measurable protein, 4.4 Yo starch, 85.4 % cellulose and 7.7 YO lignin. This material was introduced. via syringe through the mouth, into the stomachs of oysters Crassostrea virginjca; these were then held for 24 h in 13 ppt filter-sterilized seawater at 25 "C. A second group of C, virginica was treated identically, except for the addition of 5 mg I-' of the antibiotics chlorarnphenlcol and rifampicin to both food material and seawater. Direct enumeration (DAPI) of bacteria demonstrated that treatment with antibiotics eliminated bacteria from the oysters' stomach fluid. The I4C specific activities of cell-free hemolymph and tissue samples taken 24 h after feeding indicated that oysters were able to digest and absorb carbon from the S. alterniflora mater~al with a mean efficiency of 1.3 %. There were no significant differences (ANOVA, p > 0.05) in the digestion and absorption of I4C material between antibiotic treated and untreated oysters. Furthermore, in vjtro cellulolytic activities of tissue homogenates of antibiotic treated oysters were not significantly different (ANOVA, p > 0.05) from those of untreated oysters. These results indicate that oysters are able to digest only small amounts of refractory cellulosic material and that this process is not enhanced by bacterla present in the stomach. In vitro characterization of the cellulolytic enzymes of the crystalline style of C. virginica under aseptic conditions indicated the presence of P-1,4-glucanase (Cx cellulase) activity that released oligosaccharides from the S. alterniflora material. Neither C, cellulase, capable of degrading crystalline cellulose, nor $-glucosidase activities were detected, using cotton fibre and cellobiose as substrates, respectively. These results suggest that the principal function of style cellulase activity is the partial depolymerisation of refractory amorphous cellulose, perhaps aiding the digestion of algal cells and detritus.

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Chitinase Activity in Estuarine Waters

Smucker¹,

Kim²

1991

Microbial Enzymes in Aquatic Environments

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Glycosidases in the american oyster, Crassostreavirginica Gmelin, digestive tract

Cited by 14 publications

References 11 publications

Utilization of detritus and bacteria as food sources by two bivalve suspension-feeders, the oyster Crassostrea virginica and the mussel Geukensia demissa

Utilization of detritus and bacteria as food sources by two bivalve suspension-feeders, the oyster Crassostrea virginica and the mussel Geukensia demissa

Digestion and absorption of refractory carbon from the plant Spartina alterniflora by the oyster Crassosfrea virginica

Chitinase Activity in Estuarine Waters

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