Purification and characterization of cathepsin S from hepatopancreas of carp Cyprinus carpio

SUMMARY: Cathepsin S was purified from carp hepatopancreas to homogeneity up to 300-fold. The amino acid sequence of its NH₂-terminus was determined to be V-P-D-A-M-D-W-Y-N-K-G-Y-V-T-D-V-K-N-Q. On the contrary, that of purified cathepsin L from carp hepatopancreas was to be V-P-N-S-L-D-W-R-E-K-G. Purified cathepsin S consisted of a single chain with 37 kDa estimated by sodium dodecylsulfate–polyacrylamide gel electrophoresis. The enzyme had strong hydrolytic activity toward Z-Phe-Arg-MCA with the pH optimum of 7.0, but this lacked the ability to hydrolyze most of the other MCA substrates. The optimum pH of cathepsin S for protein substrate (carp myosin heavy chain) was also to be pH 7.0. These properties of purified cathepsin S obviously differ from cathepsins B and L. The enzyme activity was totally inhibited by E-64, leupeptin, 5–5'-dithiobis (2-nitro-benzoic acid) and p -tosyl-lys chloromethylketone as well.     

Effects of restrictive suckling on postpartum reproductive performance in mares

Quarter Horse mares (n = 30) and their foals were used in a 2-year study. Objectives of the study were (i) to determine the effects of a treatment regimen, which permitted nursing for four 1-hour periods each day, on the postpartum reproductive performance of the dams, and (ii) to assess the effects of this procedure on the growth and development of foals. Mares in the restricted suckling treatment group showed estrus and ovulated sooner (P less than 0.01) after parturition than did control mares during the first year of the study, but not during the second year. Plasma progesterone concentrations were similar for both treated and control mares and remained less than 1 ng/ml from parturition to ovulation. Conception rates were not significantly influenced by treatment. However, two mares which had records of failing to have estrus while nursing a foal were bred and ovulated, and one of the two conceived while on the restricted suckling treatment. The absence of treatment effects on any of the variables measured in the foals indicates that restricted suckling did not impair foal growth and development.     

The distribution pattern of Halicephalobus gingivalis in a horse is suggestive of a haematogenous spread of the nematode

The majority of Halicephalobus gingivalis-infections in horses have been fatal and are usually not diagnosed before necropsy. Therefore, knowledge about the nematode and the pathogenesis of infection in horses is limited. This has resulted in an on-going discussion about the port of entry and subsequent dissemination of H. gingivalis within the host. The present case of H. gingivalis-infection in a horse was diagnosed ante mortem. Post mortem findings, the distribution pattern of H. gingivalis nematodes in the brain, a high prevalence of inflammation in close relation to blood vessels, and the presence of the nematode in multiple organs with a disseminated pattern of distribution strongly suggested a haematogenous spread of the nematode in the horse.     

Substrate specificity of carp hepatopancreatic cathepsin S for peptides and myofibrillar proteins

SUMMARY: From 250 g of carp hepatopancreas, 0.29 mg of the purified enzyme was obtained. The bond specificity of cathepsin S for α-neoendorphin and neurotensin was ⁶Arg-⁷Lys and ³Tyr-⁴Glu, respectively. The cleavage sites for insulin B-chain were estimated to be the bonds at ³Asn-⁴Gln, ⁶Leu-⁷Cys, ¹²Val-¹³Glu, ¹³Glu-¹⁴Ala, ¹⁶Tyr-¹⁷Leu, ²²Arg-²³Gly, ²⁴Phe-²⁵Phe and ²⁶Tyr-²⁷Thr. P2 position on these peptides were bulky and hydrophobic amino acid residues such as Phe or Leu, small amino acid residues such as Gly, Ala and Val were also accepted in these positions. Regarding the protein substrates, cathepsin S degraded carp α-actinin, actin, tropomyosin and troponins T and I although the proteolyzing speeds were distinct from one another.