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41.
R. D. Lillie P. Pizzolato R. Henderson P. Donaldson 《Histochemistry and cell biology》1970,24(2):156-158
Summary Alcohol fixed blood films and fresh blocks of spinal cord were immersed in phosphate buffered neutral 10% formol for graded intervals, the films for 10, 30 min, 1, 2, 4, 8, 24 hr; the blocks for 2, 4, 6, 24 hr at 3 and 24° C; 1, 3, 7, 14, 21, 28, 42, 56 da, 3 and 14 mo at 24–26°. Graded deaminations in 2 N NaNO2/HAc at 3° C were applied: 1, 2, 5, 10, 20, 30 min; 1, 2, 4, 6, 8, 12, 18, 24, 36 hr. Blood films were stained at pH 6 and 6.5, tissue at pH 4.5 and 5.0, both in azure A eosin B. The point at which erythrocytes reached a slightly bluish green was taken as the end point, since no further color change occurred on further exposure and erythrocytes were the last of usually deamination susceptible tissue elements to lose their oxyphilia on deamination. Deamination of alcohol fixed blood films is completed in about 2 min, of sublimate fixed spinal cord in about 1 hr. Progressive formaldehyde exposure increased deamination time of blood films to 10–20 min in 1 hr, to 6–8 hr in 4 hr and to 12 hr in 24 hr. The tissue deamination showed similar progressive increase of deamination time, slower with 3° C fixation than with 24–26°, reaching 18–36 hr by about 3 days formol, and remaining about the same thereafter.Supported by National Cancer Institute Grant No. C-04816, National Institutes of Health. 相似文献
42.
H. M. Henderson 《The Biochemical journal》1965,95(3):775-779
1. Evidence is presented for the presence of pyridoxine phosphate oxidase in aqueous extracts of Escherichia coli. Some comparison is made with pyridoxamine phosphate oxidase. 2. Isoniazid and iproniazid were found to combine with pyridoxal phosphate, but isoniazid did not combine with either pyridoxamine phosphate or pyridoxine phosphate. Both oxidase activities were somewhat inhibited by benzylamine and putrescine, but not by phenethylamine or cadaverine. 3. The significance of pyridoxine phosphate oxidase in cell metabolism is discussed. 相似文献
43.
We assessed respiratory muscle response patterns to chemoreceptor stimuli (hypercapnia, hypoxia, normocapnic hypoxia, almitrine, and almitrine + CO2) in six awake dogs. Mean electromyogram (EMG) activities were measured in the crural (CR) diaphragm, triangularis sterni (TS), and transversus abdominis (TA). Hypercapnia and normocapnic hypoxia caused mild to marked hyperpnea [2-5 times control inspiratory flow (VI)] and increased activity in CR diaphragm, TS, and TA. When hypocapnia was permitted to develop during hypoxia and almitrine-induced moderate hyperpnea, CR diaphragm activity increased, whereas TS and TA activities usually did not change or were reduced below control. Over time in hypercapnia, CR diaphragm, TS, and TA were augmented and maintained at these levels over many minutes; with hypoxic hyperventilation CR diaphragm, TS, and TA were first augmented but then CR diaphragm remained augmented while TS and, less consistently, TA were inhibited over time. Marked hyperpnea (4-5 times control) due to carotid body stimulation increased TA and TS EMG activity despite an accompanying hypocapnia. We conclude that in the intact awake dog 1) carotid body stimulation augments the activity of both inspiratory and expiratory muscles; 2) hypocapnia overrides the augmenting effect of carotid body stimulation on expiratory muscles during moderate hyperpnea, usually resulting in either no change or inhibition; 3) at higher levels of hyperpnea both chemoreceptor stimulation and stimulatory effects secondary to a high ventilatory output favor expiratory muscle activation; these effects override any inhibitory effects of a coincident hypocapnia; and 4) expiratory muscles of the rib cage/abdomen may be augmented/inhibited independently of one another. 相似文献
44.
H B Dixon R A Giddens R A Harrison C E Henderson W E Norris D M Parker R N Perham P Slater M J Sparkes 《Journal of enzyme inhibition》1991,5(2):111-117
Acylphosphonic acids, R-CO-PO(OH)2, have been synthesized by the steps [formula: see text] of which the last is new and provides a mild method for de-esterifying acylphosphonic acids. Their reductive amination gives a simple way of making 1-aminoalkylphosphonic acids. Acetylphosphonic acid inhibited NAD+ reduction by pyruvate with the pyruvate dehydrogenases from Escherichia coli and Bacillus stearothermophilus. The inhibition was competitive with pyruvate, with Ki of 6 microM for the E. coli enzyme (pyruvate Km 0.5 mM) and one of 0.4 mM of the B. stearothermophilus enzyme (pyruvate Km 0.1 mM). Acetylphosphonate and its monomethyl ester are substates for pig heart lactate dehydrogenase, with Km values of 15 mM and 10 mM respectively (pyruvate Km 0.05 mM) and specificity constants one thousandth that for pyruvate. 相似文献
45.
46.
Gillian Henderson 《Biometals》1989,2(2):83-88
Summary Growth ofSaccharomyces cerevisiae on non-fermentable medium was more sensitive to inhibition by chromate than growth on fermentable medium. Chromate was selectively toxic against oxygen uptake in cells grown in non-fermentable medium and also inducedpetite mutations. CdO demonstrated similar but lesser effects on growth and respiration. However, molybdate had little toxicity to yeast non-fermentable growth and stimulated oxygen uptake in cells grown in fermentable and non-fermentable media. These results suggest that chromate, a carcinogen, may act more directly against the mitochondria ofS. cerevisiae than related chemical species, CdO and molybdate. 相似文献
47.
Noninfectious human immunodeficiency virus type 1 mutants deficient in genomic RNA. 总被引:84,自引:64,他引:20 下载免费PDF全文
R J Gorelick S M Nigida Jr J W Bess Jr L O Arthur L E Henderson A Rein 《Journal of virology》1990,64(7):3207-3211
All retroviruses contain, in the nucleocapsid domain of the Gag protein, one or two copies of the sequence Cys-X2-Cys-X4-His-X4-Cys. We have generated a series of mutants in the two copies of this motif present in human immunodeficiency virus type 1. These mutants encoded virus particles that were apparently composed of the normal complement of viral proteins but contained only 2 to 20% of the normal level of genomic RNA. No infectivity could be detected in the mutant particles, while 10(5) infectious U were present in an equivalent amount of wild-type particles. Thus, the mutants have another defect in addition to the inefficiency with which they encapsidate genomic RNA. Our results show that both copies of the motif are required for normal RNA packaging and for infectivity. Mutants of this type may have important applications, including nonhazardous materials for research, immunogens in vaccine and immunotherapy studies, and diagnostic reagents. 相似文献
48.
K Rithidech J A Hotchkiss W C Griffith R F Henderson A L Brooks 《Mutation research》1990,241(1):67-73
To determine whether ozone is clastogenic at environmentally relevant exposure levels, rats were exposed for 6 h to 0.0, 0.12, 0.27, or 0.80 ppm ozone. The alveolar macrophages were isolated from animals sacrificed 28 h after the end of the exposure. The mitotic index and frequency of chromosome aberrations were determined. No change in the mitotic index was detected following 0.12 ppm ozone exposure. A significant decrease in mitotic index was observed after exposure to 0.27 ppm ozone; a significant (4-fold) increase in the frequency of dividing macrophages was detected following exposure to 0.8 ppm ozone. Only chromatid-type aberrations were observed. There was a significant increase in the frequency of cells with chromatid gaps and in the frequency of cells with chromatid deletions. Animals exposed to 0.27 ppm ozone had the highest proportion of cells with chromatid deletions (0.172) relative to background level (0.028). No exchanges or chromosome-type aberrations were detected in any of the animals. These data suggest that ozone, at relatively low levels, is clastogenic in macrophages from exposed rats. 相似文献
49.
Gag precursors of HIV and SIV are cleaved into six proteins found in the mature virions 总被引:10,自引:0,他引:10
L E Henderson R C Sowder T D Copeland S Oroszlan R E Benveniste 《Journal of medical primatology》1990,19(3-4):411-419
During retroviral maturation gag precursors are proteolytically cleaved to mature gag proteins. The number of mature gag proteins and their order in the gag precursors of HIV-I3B, SIVMne (captive macaque isolate), and SIVCat (wild mangabey isolate) has been determined by N-terminal amino acid sequence analysis of mature gag proteins and alignment with predicted sequences of homologous gag precursors. For HIV-1 and SIVs maturation proteolysis results in six gag proteins and the gag precursor cleavage pattern is distinctive and different from cleavage patterns for all other known retroviruses. 相似文献
50.