Cloning and expression of the superoxide dismutase gene of the feline strain of Porphyromonas gingivalis: immunological recognition of the protein by cats with periodontal disease.

Recent evidence suggests that feline members of the genus Porphyromonas are of consequence in periodontal disease in cats. Several possible virulence factors from feline strains of Porphyromonas gingivalis have been described that have similarities to those of human P. gingivalis.

Inheritance of levamisole and benzimidazole resistance in an isolate of Haemonchus contortus.

Reciprocal crosses between an isolate of Haemonchus contortus resistant to both benzimidazole and levamisole anthelmintics and a susceptible isolate were performed in order to determine the mode of inheritance of these resistances. F1 and F2 generations and parent isolates were assayed for susceptibility to thiabendazole and levamisole in vitro. For each drug all of the filial generations were intermediate in susceptibility between the parent isolates, and analysis indicated that resistance was inherited as an incompletely recessive character determined by more than one gene in each case.

Cryopreservation of the first-stage larvae of trichostrongylid nematode parasites.

First stage (L1) larvae of Haemonchus contortus, Trichostrongylus colubriformis and Ostertagia circumcincta can be cryopreserved in the presence of DMSO using a two-step freezing protocol involving an initial period at -80 degrees C prior to transfer to liquid nitrogen. Thawed L1 larvae continue development in vitro producing third stage (L3) larvae that are infective to sheep when dosed per os. Establishment rates for L3 larvae grown from thawed L1 larvae were 40 and 80% for H.