ABSTRACT
Objective To identify the characteristics of Candida utilis uricase and that of Bacillus fastidious intra-cellular uricase.Methods The new strains were cultivated to prepare the uricase.Then the uricase was purified by ammonium sulfate fractionation precipitation,DEAE-cellulose 52 chromatography and preparative PAGE.The activity,characterization and subunit constitution were determined with the purified uricase.Results The two uricas-es were the iso-tetramer.The single peptide chain molecular weight and total molecular weight of Candida utilis uricase were 33.0 ku and 134.0 ku individually,the optimum pH was close to 8.8 and more than 50% activity was reserved at pH 7.4,the Michaelis-Menten constant was (32.8 ± 3.1) μmol/L (n = 10) and the inhibition constant of xanthine was (4.8 ± 0.2) μmol/L(n = 3) for this uricase.For Bacillus fastidious intracellular uricase,its single peptide chain molecular weight and total molecular weight were 35.7 ku and 151.0 ku,the optimum pH was over 9.0 and less than 30% activity left at pH 7.4,the Michaelis-Menten constant and the inhibition constant of xanthine were (204 ± 14) μmol/L(n = 8) and (41 ± 7) μmol/L(n = 5) individually for it.Conclusion Through the research,a significant theoretical basis was funded for constructing hybrid medicinal uricase to treat diseases as-sociated with hyperuricemia.
ABSTRACT
This study examined endogenous cannabinoid (ECB)-anandamide (AEA) and its cannabinoid receptors (CBR) in mice liver with the development of schistosoma japonicum. Mice were infected with schistosoma by means of pasting the cercaria onto their abdomens. Liver fibrosis was pathologically confirmed nine weeks after the infection. High performance liquid chromatography (HPLC) was employed to determine the concentration of AEA in the plasma of mice. Immunofluorescence was used to detect the expression of CBR1 and CBR2 in liver tissue. Morphological examination showed typical pathological changes, with worm tubercles of schistosoma deposited in the liver tissue, fibrosis around the worm tubercles and infiltration or soakage of inflammatory cells. Also, CBR1 and CBR2 were present in hepatocytes and hepatic sinusoids of the two groups, but they were obviously enhanced in the schistosoma-infected mice. However, the average optical density of CBR1 in the negative control and fibrosis group was 13.28+/-7.32 and 30.55+/-7.78, and CBR2 were 28.13+/-6.42 and 52.29+/-4.24 (P<0.05). The levels of AEA in the fibrosis group were significantly increased as compared with those of the control group. The concentrations of AEA were (0.37+/-0.07) and (5.67+/-1.34) ng/mL (P<0.05). It is concluded that the expression of endocannabinoids AEA and its cannabinoid receptor CBR were significantly increased in schistosoma-infected mice. Endogenous endocannabinoids may be involved in the development of schistosoma-induced liver fibrosis.