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91.
92.
Ninety-seven strains of Cryptococcus neoformans and C. bacillisporus were examined for 44 biochemical characters and the results were analyzed numerically. One phenon emerged at the 86% level of similarity when strains were clustered according to their M-similarity values. All strains grew in ten carbon sources (D-glucose, D-galactose, arbutin, maltose, sucrose, D-melezitose, D-xylose, D-mannitol, D-glucitol, and meso-inositol), and also grew at 37 ° C and produced urease and phenoloxidase. None of them grew in melibiose, lactose, nor valine, and none reduced nitrate to nitrite. Comparison of selected biochemical characters, creatinine utilization, and serotypes of 49 aberrant strains is presented. Forty-eight of the 97 strains produced the Filobasidiella state either alone or when paired with a strain of compatible mating-type. Filobasidiella neoformans serotypes A and D were interfertile with compatible mating-types of F. bacillispora serotypes B and C. The 44 biochemical characters and 4 serotypes did not predict barriers to mating competence. The present study further substantiates that Filobasidiella neoformans and F. bacillispora are one species. 相似文献
93.
94.
A microorganism that produces glucose isomerase was isolated from soil and identified as a strain of Streptomyces flavogriseus. The organism produced a large quantity of glucose isomerase when grown on straw hemicellulose, xylan, xylose, and H2SO4 hydrolysate of ryegrass straw. The organism produced glucose isomerase both intra- and extra-cellularly. The highest level of intracellular glucose isomerase (3.5 U/ml) was obtained in about 36 h by a culture grown on straw hemicellulose; the extracellular enzyme (1.5 U/ml) appeared in cultures grown for about 72 h. About equal levels of enzyme were produced in cultures grown on straw hemicellulose, xylan, xylose, and H2SO4 hydrolysate of straw, but production of the enzyme was drastically reduced when the organism was grown on other carbon sources. As a nitrogen source, corn steep liquor produced the best results. Soy flour extract, yeast extract, and various peptones also were adequate substrates for glucose isomerase production. Addition of Mg2+, Mn2+, or Fe2+ to the growth medium significantly enhanced enzyme production. The organism, however, did not require Co2+, which is commonly required by microorganisms used in the production of glucose isomerase. 相似文献
95.
The presence of Ca2+-ATPase activities with high-affinity sites for Ca2+ in brush border as well as basolateral plasma membranes of rat duodenal epithelium has been reported previously (Ghijsen, W.E.J.M. and van Os, C.H. (1979) Nature 279, 802–803). Since both plasma membranes contain alkaline phosphatase (EC 3.1.3.1), which also can be stimulated by Ca2+, the substrate specificity of Ca2+-induced ATP-hydrolysis has been studied to determine whether or not alkaline phosphatase and Ca2+-ATPase are two distinct enzymes. In basolateral fragments, the rate of Ca2+-dependent ATP-hydrolysis was greater than that of ADP, AMP and at Ca2+ concentrations below 25 μM. At 0.2 mM Ca2+ the rates of ATP, ADP, AMP and hydrolysis were not significantly different. In brush border fragments the rates of ATP, ADP and AMP hydrolysis were identical at low Ca2+, but at 0.2 mM Ca2+, Ca2+-induced hydrolysis of ADP and AMP was greater than either ATP or . Alkaline phosphatase in brush border and basolateral membranes was inhibited by 75% after addition of 2.5 mM theophylline. Ca2+-stimulated ATP hydrolysis at 1 μM Ca2+ was not sensitive to theophylline in basolateral fragments while the same activity in brush border fragments was totally inhibited. At 0.2 mM Ca2+, Ca2+-induced ATP hydrolysis in both basolateral and brush border membranes was sensitive to theophylline. Oligomycin and azide had no effect on Ca2+-stimulated ATP hydrolysis, either at low or at high Ca2+ concentrations. Chlorpromazine fully inhibited Ca2+-stimulated ATP hydrolysis in basolateral fragments at 5 μM Ca2+, while it had no effect in brush border fragments. From these results we conclude that, (i) Ca2+-ATPase and alkaline phosphatase are two distinct enzymes, (ii) high-affinity Ca2+-ATPase is exclusively located in basolateral plasma membranes, (iii) alkaline phosphatase activity, present on both sides of duodenal epithelium, is stimulated slightly by low Ca2+ concentrations, but this Ca2+-induced activity is inhibited by theophylline and shows no specificity with respect to ATP, ADP or AMP. 相似文献
96.
The biogenesis of rat mitochondrial ATPase. Two subunits are synthesized inside the mitochondria 总被引:3,自引:0,他引:3
Isolated mitochondria from regenerating rat liver synthesize at least five different polypeptides with molecular weights ranging from 19 000 to 43 000. Among these, two polypeptides with molecular weights of 22 000 and 25 ooo could be identified as ATPase subunits. It has previously been shown that these subunits, designated 6 and 7, are lacking in the ATPase complex that is formed in vivo when mitochondrial protein synthesis is blocked by thiamphenicol treatment. The 22 000 Mr protein is enriched in the fraction containing the fully assembled ATPase complex, whereas the 25 000 Mr protein is not. 相似文献
97.
The cellular immune response (MIF, E-rosette formation and changes in nucleolar morphology of lymphocytes) was followed as
related to age and antigenic stimulation. MIF in healthy infants increased from the 2nd to the 12th week of life as compared
with the first week, probably due to BCG vaccination. The total and active E-rosette formation did not change during the whole
period of investigation. Ring-shaped nucleoli increased gradually from the second week of life. Active nucleoli increased
up to the 4th week,i.e. after BCG vaccination and then slowly decreased. Micronucleoli being high in the first week, decreased during 24 weeks of
life. After artificial colonization of the intestine the production of MIF was slightly lower in colonized infants than in
controls from the 2nd to the 12th week. The other parameters followed were not influenced by colonization. 相似文献
98.
The oviducts of 24 mares were examined to determine the site of retention of unfertilized eggs. The ampullary-isthmic junction regions of 42 of the 48 oviducts were serially sectioned and examined histologically. The remaining parts of the oviducts were flushed and the flushings searched microscopically. Of 45 eggs located, 40 were in the sectioned segments of 24 oviducts and only 5 were in the flushings. All but one of the sectioned segments contained prominent masses of material obstructing the lumen, but these were apparently not the direct cause of egg retention since eggs were found on both sides of them. 相似文献
99.
Five sets of cytotoxic effector cells were generated, using haploidentical, first degree relatives in five different families, against the HLA-A3; B7 serological determinants combined with different DR antigens. When tested against a panel of cells bearing combinations of the HLA-A, -B and -DR antigens it was shown that the HLA-B7 antigen was as strong a CML target determinant alone as it was in the presence of HLA-A3. The strength of the HLA-A3 antigen as target determinant varied. With effector cells primed to the HLA-A3; B7; DR2 haplotype, the A3 antigen alone behaved as a weak target determinant. When the same target cells were tested with the effector cells generated against HLA-A3; B7 without DR2, the A3 antigen behaved as a strong target determinant. A number of target cells lacking the serologically detectable HLA determinants present on the sensitizing HLA haplotype were identified as being killed by specific effector cells. These data suggest either a number of new CML target determinants controlled by different loci or the presence of a single, new locus with multiple alleles controlling CML targets. 相似文献
100.
G J Hughes C de Jong R W Fischer K H Winterhalter K J Wilson 《The Biochemical journal》1981,199(1):61-67
Native rat haemoglobins were found to bind simetryn sulphoxide to an extent 40-fold greater than human haemoglobin. This specific behaviour was studied by using only high-pressure ('performance') liquid chromatography for the preparative separation of globin chains and the isolation of peptides resulting from chemical and enzymic degradation. High recoveries (greater than 80%) of peptides throughout the procedures in combination with microsequence techniques, allow a definitive assignment of the residue undergoing modification. The haemoglobin beta-chain cystine-125 residue, with a stoichiometry of one per tetramer of rat haemoglobin, was found to be modified. Stereochemical implications of this finding are discussed. Simetryn sulphoxide would appear to be useful as a specific reagent for the mapping of exposed thiol residues in proteins. 相似文献