Trichinella spiralis thymidylate synthase: cDNA cloning and sequencing, and developmental pattern of mRNA expression.

The persistent expression of thymidylate synthase activity has previously been demonstrated not only in adult forms, but also in non-developing muscle larvae of Trichinella spiralis and T. pseudospiralis, pointing to an unusual pattern of cell cycle regulation, and prompting further studies on the developmental pattern of T. spiralis thymidylate synthase gene expression.

Effect of cyclosporin A on immunological response in lungs of guinea pigs infected with Trichinella spiralis.

The effects of cyclosporin A (CsA), a potent immunosuppressive drug with antiparasitic activity, on the innate immunological response in guinea pig lungs during an early period (6th and 14th days) after T. spiralis infection were studied. CsA treatment of T.

Trichinella spiralis and Trichinella pseudospiralis: developmental patterns of enzymes involved in thymidylate biosynthesis and pyrimidine salvage.

Thymidylate synthase, dihydrofolate reductase and dUTPase specific activities were found to remain at a high and constant level in crude extracts from adult worms of Trichinella spiralis, as well as from muscle larvae of both Trichinella spiralis (isolated 1-24 months after infection) and Trichinella pseudospiralis (isolated 5.5-13 months after infection). The results obtained with Trichinella pseudospiralis muscle larvae isolated with the use of pepsin did not differ from those obtained when pepsin was not used.

Trichinella spiralis: the infectivity of synchronous newborn larvae of different ages inoculated intraocularly.

Trichinella spiralis infection results in the transformation of muscle cells into a new, non-muscular cell called the nurse cell, and the nurse cell-muscle larva complex is finally created. To investigate whether T. spiralis infectivity is NBL age-dependent, five groups of synchronous newborn larvae (sNBL) were obtained at 1, 9, 24, 48, and 72 h of age and were inoculated into mice by intravenous injection into the retro-orbital venous plexus.

Trichinella spiralis: proteinases in the larvae.

Under in vitro conditions, muscle larvae of Trichinella spiralis secreted minute amounts of a cysteine proteinase into the outer environment from the stichosome. The proteinase hydrolyzed azocoll at pH 5.0 but not a number of synthetic N-blocked and N-unsubstituted proteinase substrates at this pH.