Enzymes of Thymidylate Biosynthesis in Trichinella Pseudospiralis Muscle Larvae and Caenorhabditis Elegans Dauer Larvae
All species in the genus Trichinella, between them T. spiralis and T. pseudospiralis, have been successful in colonizing striated skeletal muscle tissue and remain infective in this niche for months to years. Trichinella spiralis causes trichinellosis, a serious disease in man and other mammals. Mating of adult worms (developing from infective larvae, deriving from digested infected meat) occurs in a non membrane-bound portion of columnar epithelium of the host’s small intestine. The fertilized females enter the intestinal wall and release to the bloodstream the newborn larvae. Each of these penetrates host’s skeletal muscle cell and lives in its modified portion, the nurse cell, surrounded by a collagen capsule around which a circulatory rete develops. The nurse cell development, initiated by T. spiralis infection, is associated with a variety of changes, including cell cycle re-entry and induction of DNA synthesis, followed by the apparent G2/M arrest of the infected cell in the cell cycle. Similar changes appear to be caused by T. pseudospiralis infection, albeit the nurse cell complexes are not encapsulated by collagenous fibers and the larvae may move between muscle cells (1).
KeywordsThymidine Kinase Thymidine Phosphorylase Nurse Cell Dihydrofolate Reductase Muscle Larva
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