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101.
Summary Mitochondrial creatine kinase (CK) purified from canine myocardium showed a single protein band on SDS-PAGE and was free of
MMCK. Its amino acid composition was different than MMCK or BBCK and did not react to antiserum to MMCK or BBCK. Using purified
mitochondrial, MM and BBCK, the velocity of reaction (V) was estimated for creatine phosphate (CP), creatine (C), adenosine
triphosphate (ATP) and adenosine diphosphate (ADP) over a wide range of concentrations including those at Vmax. The values for Km (mM/L) derived from Lineweaver-Burke plots are shown:
The affinity of mitochondrial CK for C is much greater than MMCK which is compatible with the energy shuttle hypothesis, namely
ATP is converted by mitochondrial CK to CP, and then diffuses to the myofibril for conversion to ATP for utilization. 相似文献
102.
Anil K. Sinha V. Ann Linscombe B. Bhaskar Gollapudi George C. Jersey Colin N. Park 《Cell biology and toxicology》1985,1(4):333-342
Sister chromatid exchanges (SCE) were analyzed in peripheral blood lymphocytes from a select group of 71 healthy men, 56 nonsmokers and 15 cigarette smokers. In addition to estimating baseline SCE, data were examined to seek relationships of SCE frequencies to age and smoking. The baseline value of 7.53 SCE per cell from the 56 nonsmokers was within the range (5.60 to 9.10 SCE/cell) reported for other human populations. No relationship was found between the mean SCE frequency per cell and age. However, a significant increase in the SCE mean value was observed in smokers as compared to nonsmokers. The results of this study are compared with those of other reports on SCE effects of age and smoking.Abbreviations BUdR
5-bromo,2-deoxyuridine
- SCE
sister chromatid exchange 相似文献
103.
We report the genetic mapping of pheU , an Escherichia coli gene for phenylalanine tRNA. This gene was located near 94.5 min on the E. coli map. There are no other known tRNA or ribosomal genes in its immediate vicinity. 相似文献
104.
105.
Presynaptic Nicotinic Cholinergic Receptors Labeled by [3 H]Acetylcholine on Catecholamine and Serotonin Axons in Brain 总被引:5,自引:0,他引:5
Nicotinic cholinergic receptor binding sites labeled by [3H]acetylcholine were measured in the cerebral cortices, thalami, striata, and hypothalami of rats lesioned by intraventricular injection of either 6-hydroxydopamine or 5, 7-dihydroxytryptamine. In addition, [3H]acetylcholine binding sites were measured in the cerebral cortices of rats lesioned by injection of ibotenic acid into the nucleus basalis magnocellularis. [3H]Acetylcholine binding was significantly decreased in the striata and hypothalami of both 6-hydroxydopamine- and 5,7-dihydroxytryptamine-lesioned rats. There was no change in binding in the cortex or thalamus by either lesion. Ibotenic acid lesions of the nucleus basalis magnocellularis, which projects cholinergic axons to the cortex, did not alter [3H]acetylcholine binding. These results provide evidence for a presynaptic location of nicotinic cholinergic binding sites on catecholamine and serotonin axons in the striatum and hypothalamus. 相似文献
106.
Bolinopsis vitrea is a warm water lobate ctenophore which doesnot overlap in its distribution with Mnemiopsis mccradyi incontiguous waters. We examined its feeding ecology on a seriesof cruises. B. virrea ingested increasingly more prey at higherfood concentrations (2100 prey l1) but feedingeffort (clearance rate) decreased with increasing food availability.On a dry weight basis, smaller tentaculate Bolinopsis ingestedseveral times more than larger lobates, but based on carbonweight, specific ingestion was fairly uniform over the entiresize range investigated (660 mm total length). Bolinopsiscollected during the daytime in the Bahamas rarely had morethan three prey items in their guts. These results and laboratorymeasurements of digestion times (av. = 1.9 h) allowed computationof daily rations, which could not account for the metabolicrequirement as measured on the same cruises. Results of feedingexperiments, however, implied that prey densities in excessof 111 were sufficient to sustain a growing populationof Bolinopsis. Prey concentrations about an order of magnitudehigher were required for M. mccradyi based on similar experiments.These results were in general agreement with observed densitiesand distributions of ctenophores and their zooplankton preyin the Bahamas and coastal South Florida. 相似文献
107.
Cat pancreatic eicosapeptide and its biosynthetic intermediate. Conservation of a monobasic processing site. 下载免费PDF全文
Pancreatic eicosapeptide is synthesized together with the hormone pancreatic polypeptide in a common precursor in the major endocrine cell type of the duodenal pancreas. This processing has been previously demonstrated in man and in the dog. In the present study the cat pancreatic eicosapeptide and a C-terminally extended form of this were isolated and characterized from acid/ethanol extracts of pancreas by gel filtration and reverse-phase h.p.l.c. The sequence homology in the C-terminal part of the eicosapeptides from different species was shown to continue to the other side of the monobasic cleavage site in the extended intermediate form, whereas the end of the extension differed both in chain length and amino acid sequence. It is concluded that the processing site in the intermediate form of the pancreatic eicosapeptide is an example of a proline-directed monobasic cleavage site that has been conserved during evolution. 相似文献
108.
Synergism of v-myc and v-Ha-ras in the in vitro neoplastic progression of murine lymphoid cells. 总被引:19,自引:11,他引:8 下载免费PDF全文
R C Schwartz L W Stanton S C Riley K B Marcu O N Witte 《Molecular and cellular biology》1986,6(9):3221-3231
Murine bone marrow was either singly or doubly infected with retroviral vectors expressing v-myc (OK10) or v-Ha-ras. The infected bone marrow was cultured in a system that supports the long-term growth of B-lineage lymphoid cells. While the v-myc vector by itself had no apparent effect on lymphoid culture establishment and growth, infection with the v-Ha-ras vector or coinfection with both v-myc and v-Ha-ras vectors led to the appearance of growth-stimulated cell populations. Clonal pre-B-cell lines stably expressing v-Ha-ras alone or both v-myc and v-Ha-ras grew out of these cultures. In comparison with cell lines expressing v-Ha-ras alone, cell lines expressing both v-myc and v-Ha-ras grew to higher densities, had reduced dependence on a feeder layer for growth, and had a marked increase in ability to grow in soft-agar medium. The cell lines expressing both oncogenes were highly tumorigenic in syngeneic animals. These experiments show that the v-myc oncogene in synergy with v-Ha-ras can play a direct role in the in vitro transformation of murine B lymphoid cells. 相似文献
109.
I Tattersall J H Schwartz 《Folia primatologica; international journal of primatology》1983,41(3-4):231-239
A new primate genus and species, represented by isolated teeth, is described from the middle Eocene Alsatian site of Bouxwiller. This new form is closely related to Egerkingen 'Adapis' ruetimeyeri, for which a new genus is proposed because of the important distinctions from type Adapis present in its dentition. Nonetheless, both new genera are closely related to Adapis and Leptadapis. 相似文献
110.
Catalase and superoxide dismutase in Escherichia coli 总被引:9,自引:0,他引:9
C E Schwartz J Krall L Norton K McKay D Kay R E Lynch 《The Journal of biological chemistry》1983,258(10):6277-6281
We assessed the roles of intrabacterial catalase and superoxide dismutase in the resistance of Escherichia coli to killing by neutrophils. E. coli in which the synthesis of superoxide dismutase and catalase were induced by paraquat 10-fold and 5-fold, respectively, did not resist killing by neutrophils. When bacteria were allowed to recover from the toxicity of paraquat for 1 h on ice and for 30 min at 37 degrees C, they still failed to resist killing by neutrophils. Induction of the synthesis of catalase 9-fold by growth in the presence of phenazine methosulfate did not render E. coli resistant to killing by either neutrophils or by H2O2 itself. The lack of protection by intrabacterial catalase from killing by neutrophils could not be attributed to an impermeable bacterial membrane; the evolution of O2 from H2O2 was no less rapid in suspensions of E. coli than in lysates. The failure of intrabacterial catalase or superoxide dismutase to protect bacteria from killing by neutrophils might indicate either that the flux of O-2 and H2O2 in the phagosome is too great for the intrabacterial enzymes to alter or that the site of injury is at the bacterial surface. 相似文献