Comparison of the Uptake of Vitamin B12 by Spirometra mansonoides and Hymenolepis diminuta and the Functional Groups of B12 Analogs Affecting Uptake

Uptake of 57Co-vitamin B12 (CN-Cbl) by spargana (larvae) of the pseudophyllidean tapeworm, Spirometra mansonoides, was affected by temperature, was saturable with respect to concentration of CN-Cbl in the medium, and was inhibited in the presence of several structural analogs of CN-Cbl. In uptake st...

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Bibliographic Details
Published in:The Journal of parasitology 1976-02, Vol.62 (1), p.94-101
Main Authors: Tkachuck, Richard D., Weinstein, Paul P., Mueller, Justus F.
Format: Article
Language:English
Subjects:
Animals
Benzimidazoles
Cestoda - metabolism
Cobamides - pharmacology
Enzymes
Flasks
Functional groups
Intestines
Male
Mice
Molecules
Parasitism
Parasitology
Sparganum - metabolism
Structure-Activity Relationship
Tapeworms
Vitamin B 12 - analogs & derivatives
Vitamin B 12 - metabolism
Vitamin B12
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Summary:Uptake of 57Co-vitamin B12 (CN-Cbl) by spargana (larvae) of the pseudophyllidean tapeworm, Spirometra mansonoides, was affected by temperature, was saturable with respect to concentration of CN-Cbl in the medium, and was inhibited in the presence of several structural analogs of CN-Cbl. In uptake studies with various analogs it was found that chemical modifications which altered the benzimidazole moiety greatly reduced the ability of the worm to take up these analogs. Modifications in which the amide groups of the propionamide side chains were removed, resulting in carboxylic acid derivatives, showed greatly reduced transport properties. The C-13 epimer in which the e-propionamide side chain is no longer on the benzimidazole side (lower) of the molecule but is inverted to a position on the upper side was freely taken up. The pharmacological implications of this last observation are discussed. Adult Hymenolepis diminuta did not take up CN-Cbl in vitro, which correlated with the finding that no CN-Cbl was detected in the worm by Ochromonas malhamensis assay.
ISSN:0022-3395
1937-2345
DOI:10.2307/3279048