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DAO 60:223-231 (2004)
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Abstract
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Physiology and lipid metabolism of Littorina saxatilis infected with trematodes
Katherine S. Arakelova1,*, Marina A. Chebotareva2, Stanislav A. Zabelinskii2
1Laboratory of Freshwater and Experimental Hydrobiology , Zoological Institute, Russian Academy of Sciences, 1, Universitetskaya Embankment, St. Petersburg, 199034 Russia 2Laboratory of Comparative Physiology,
I.M.Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 M.Thorez Avenue, St. Petersburg, 194223 Russia
*Email: gambar@ea3784.spb.edu

ABSTRACT: Physiological and biochemical alterations in Littorina saxatilis infected with larval trematodes were investigated and compared with the metabolism of non-parasitized snails. Oxygen consumption rates of infected snails differed from those
of non-infected controls in medium sized individuals (30 to 130 mg) but not in very large infected individuals (>200 mg). Small snails (0.5 to 8.5 mg) were seldom infected by parasites, and this size-class consisted only of non-infected specimens. The
specific oxygen consumption rate of infected snails was not dependent on their mass and remained constant over the size ranges investigated. Alterations in the snail metabolism appeared to be connected to injuries to digestive gland tissues caused by the
parasites. The glycogen concentration and fatty acids of neutral lipids and phospholipids in the digestive gland were determined. Infected snails differed from uninfected snails in the complete absence of glycogen in digestive gland and had proportionally
higher quantities of eicosenoic (20:1) acid in the total phospholipids. It remains unclear whether infection by trematodes activates enzymes in the snails digestive gland to synthesize eicosenoic (20:1) acid, or whether the sporocysts themselves
possess these enzymes. The role of phospholipid fatty acids in the regulation and maintenance of the parasites metabolism is briefly considered. Biochemical alterations observed in the fatty acid composition may have an adaptive significance, by
helping to stabilize the host-parasite system.
KEY WORDS: Littorina saxatilis · Metabolism · Trematodes · Digestive gland · Phospholipids · Fatty acids
Full text in pdf format

Published in DAO Vol.
60, No. 3
(2004) on September 8
Print ISSN: 0177-5103; Online ISSN: 1616-1580.
Copyright © Inter-Research, Oldendorf/Luhe, 2004
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