Absorption of disaccharides by the gut of the chiton, Crypotochiton stelleri

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1970

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Abstract

The everted sac technique was utilized to study the absorption of trehalose, maltose and sucrose by the gut of Cryptochiton stelleri. No evidence was obtained which indicated that any of the disaccharides were actively transported from the mucosal to the serosal compartments. However, each disaccharide was accumulated in significantly higher amounts in the ethanol fraction than in the ambient solution. This, plus the fact that at least 50% of this activity was in the form of unaltered disaccharide suggests that the disaccharides were actively transported into the intestinal tissue in the following decreasing order of rate of accumulation: maltose trehalose sucrose. The increased amount of activity with trehalose under anaerobic conditions suggests that the mechanism of absorption of this disaccharide in this animal is insensitive to anaerobic conditions or is characterized by exhibiting the Pasteur effect. It also suggests that this accumulation is not by active transport mechanisms or that the transport mechanism does not depend on metabolic energy. The increase seen with trehalose is probably due to its partial conversion to metabolites which would explain the fact that only 50% of the trehalose from the ethanol soluble fraction was recovered in developed spots using one-dimensional chromatography. It is obvious from the results that some digestion of the disaccharides did occur although no alterations in the disaccharides were detected. The accumulation of all three disaccharides studied in the insoluble ethanol fraction indicates that these disaccharides (which are normally quite soluble in ethanol) were being metabolized or altered in some manner. If, indeed, disaccharide transport does occur as evidenced by their high accumulation in the intestinal tissue, this is the first time that this phenomenon has been reported in this group of animals.

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