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71.
72.
The effects of gamma-irradiation on glucose oxidase activity were studied inBacillus cereus T spores. Radiation was found to activate oxidase in native spores. This activation was greatly enhanced when irradiated spores were subsequently heat-activated. Although activation by heat alone was 1.6 times that by radiation alone, the combined treatment with both radiation and heating resulted in a 12-fold enhancement of oxidase activity over that obtainable by optimum heat activation. Activation by combined treatment of gamma-rays and heat depended on the presence of exchangeable calcium during heating but not during irradiation. 相似文献
73.
An escape reaction of the hyphae from virus-containing strain Bali 1 of A. arbuscula was detected when intra- and interspecific Allomyces cultures were opposed on solid media. Hyphae of this virus-containing strain proliferate into witch-broom structures only detectable on solid media in which bunches of rhizoid-like structures remain more superficial than those of the control cultures, suggesting that metabolism of the Bali 1 strain is altered into a more aerobic type. 相似文献
74.
75.
Studies on the subcellular distribution of NADPH-linked aldehyde reductase from rat brain showed that 10% of the total reductase activity is located in the mitochondrial-synaptosomal fraction. There are differences in the percentages of reductase activity found in the synaptosomes compared to cytosol in various regions of the brain. The NADPH-linked aldehyde reductase from the synaptosomal fraction exhibited a nonlinear Lineweaver-Burk plot. This nonlinearity is due to the presence of two distinct aldehyde reductases, which can be distinguished by Michealis constants forp-nitrobenzaldehyde of 4.1×10–5 M and 2.6×10–6 M. The two NADPH-linked aldehyde reductases isolated from synaptosomes were further characterized according to pH optima, andK
i
values for inhibition by barbiturates. In addition regional distributions for the two enzymes were determined. TheK
i
values for pentobarbital for the highK
m
enzyme and the lowK
m
enzyme were estimated to be 2×10–5 M and 6×10–5 M, respectively. It was concluded from the above studies that the lowK
m
reductase is probably responsible for 3,4-dihydroxyphenylglycoaldehyde (derived from norepinephrine) reduction in brain and a role of the highK
m
enzyme for protection of neurons from high concentrations of chemically reactive aldehydes was proposed.This work was supported in part by Grants from the National Institute of Mental Health, MH 18948 from the University of Colorado Council on Research and Creative Work and by an MBS Program Grant #081-39.This work was performed in partial fulfillment of the requirements for the Ph. D. thesis. 相似文献
76.
TheLyb-2 locus responsible for the B-lymphocyte alloantigen system Lyb-2 is located on chromosome 4 at a distance of 20.6±4.9 map units fromPgm-2. A three-point cross indicated the orderLyb-2: Mup-1b Pgm-2. 相似文献
77.
J.M. Katz S.J.M. Skinner T. Wilson D.H. Gray 《Prostaglandins & other lipid mediators》1983,26(4):545-555
Mouse calvaria were maintained in organ culture without serum additives. Basal active resorption, as measured by 45Ca and hydroxyproline release, was significantly inhibited to 74% control levels by indomethacin (1.4 × 10−7 M). Prostaglandin F and prostaglandin E2 production, determined by radioimmunoassay, were both significantly lowered by this concentration of indomethacin. DNA, protein and hydroxyproline synthesis, as indices of cell toxicity, were unaffected by low concentrations of indomethacin, while concentrations of 1.4 × 10−6M inhibited protein synthesis (p<0.005). In the presence of indomethacin (1.4 × 10−7M) both PGE2 and PGF2α stimulated resorption in a dose-dependent manner, with PGE2 being the more potent. Neither prostaglandin affected hydroxyproline synthesis at low concentrations, but PGE2 had a marked inhibitory action at a higher concentration (10−6M). In combination, the effects of PGE2 and PGF2α showed no evidence of synergism or any antagonistic action. The study shows that in vitro calcium and hydroxyproline resorption in the unstimulated mouse calvaria are inhibited by indomethacin at concentrations measured in serum during human therapy. The decreased PGF and PGE2 production associated with this decreased bone resorption in the presence of non-toxic concentrations of indomethacin would suggest a role for these prostaglandins in maintaining the basal resorption of cultured bone. 相似文献
78.
Hans Lindblom U.-B. Axiö-Rredriksson Edward H. Cooper Ron Turner 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1983,273(1):107-116
Proteins excreted in urine due to renal failure were separated on Mono QTM, a new strong anion exchanger designed for fast high-resolution protein separations. The separation procedure was divided into two steps. The first step involved removal of low-molecular- weight substances by rapid desalting on a Sephadex G-25 Superfine column. In the second step, the total protein fraction (3–6 ml) was loaded onto the Mono Q column with the aid of a superloop. The proteins were adsorbed onto the top of the ion-exchanger column and gradually displaced by a combined pH and salt gradient in 40 min. The choice of ion exchanger and initial operating conditions were based on data obtained from electrophoretic titration curve experiments. Identification of separated proteins was achieved by fused rocket electrophoresis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, respectively. 相似文献
79.
Edward G. Shaskan Bruce J. Brew Marc Rosenblum Randall M. Thompson Richard W. Price 《Journal of neurochemistry》1992,59(4):1541-1546
Postmortem levels of native neopterin (D-erythro-neopterin) were measured in cerebral cortical samples from 44 human immunodeficiency virus type 1-infected and eight uninfected, nonneurological control patients. Cerebral cortical gray and white matter neopterin levels for the controls ranged from 0.5 to 7.2 pmol/mg of protein in contrast to neopterin levels in brains of the virus-infected patients, which frequently were more than threefold and occasionally more than 30-fold higher than mean control levels. Cortical neopterin levels did not correlate with severity of the acquired immunodeficiency syndrome dementia complex, but subcortical levels correlated with the presence of active human immunodeficiency virus type 1 infection, as reflected by pathological evidence of multinucleated giant cell encephalitis. Evidence of opportunistic cytomegalovirus infections in approximately 25% of the human immunodeficiency virus type 1-infected patients was associated with enhanced levels of neopterin in frontal cortex. 相似文献
80.
M Carey J Kolman D A Katz L Gradoville L Barberis G Miller 《Journal of virology》1992,66(8):4803-4813