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61.
Lisa Beltz Opendra Narayan Robert J. Adams Stephen J. Noga Albert D. Donnenberg 《Journal of medical primatology》1991,20(4):144-151
Rhesus progenitor-enriched BM was exposed overnight to SIV and cultured in a limiting dilution assay where the potential for progenitor interaction with lymphocytes or macrophages was low. Virus was consistently isolated late in culture, detection being aided by coculture with CEM174 lymphoblasts. Although infected cells had reduced clonogenic activity, colonies were indistinguishable from those derived from uninfected BM with respect to proliferative potential, morphology, and longevity in culture. Primate immunodeficiency viruses, therefore, may infect immature BM populations, directly affecting hematopoietic activity. 相似文献
62.
63.
Vasanti Deshpande Mala Rao Sulbha Keskar Chittra Mishra 《Enzyme and microbial technology》1984,6(8):371-374
The endo-1,4-β-d-glucanase [cellulase, 1,4-(1,3:1,4)-β-d-glucan 4-glucanohydrolase, EC 3.2.1.4] activity of two-day old culture filtrates of Penicillium janthinellum has been enhanced four-fold by incubating with a 10-day old culture filtrate of Penicillium funiculosum grown on the same medium. An inactive protein isolated by fractionation of two-day old culture filtrate of P. janthinellum using preparative isoelectric focusing, showed 30- to 50-fold enhancement of endo-1,4-β-d-glucanase activity. This fraction has been designated the ‘procellulase’ in the present paper. The purity of the procellulase was confirmed by analytical isoelectric focusing and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. It had a molecular weight of 68 000 and an isoelectric point of pH 3.7. 相似文献
64.
High concentrations of phosphate drastically inhibited the aerobic growth ofAzospirillum brasilense in liquid medium having a limiting concentration of combined nitrogen. No growth inhibition occurred if a high concentration of combined nitrogen was present. Aerobic growth occurred only in the presence of a very low amount of phosphate and this could be enhanced by adding norepinephrine. Addition of norepinephrine enhanced the O2 uptake by cell suspensions by almost a factor of 3. All of the intermediates of the tricarboxylic acid metabolic cycle were actively oxidized in cell-free extracts and their rate of oxidation increased in the presence of norepinephrine. 相似文献
65.
Syamal K. Chakrabarti Ajit K. Mishra Dr. Pran K. Chakrabartty 《Current microbiology》1984,11(6):343-347
Difference spectra of the crude cell-free extract ofAzospirillum brasilense sp. 7 indicate the presence of cytochrome b, cytochrome c, and one CO-binding pigment that exhibits the spectral characteristics of cytochrome o. All the pigments are present in varying concentrations at all stages of growth. With progress of the bacterial growth, there is a linear increase in the level of cytochrome b with a disproportionate increase in the level of cytochrome c. At the stationary phase, the amount of cytochrome b and c is increased by about sevenfold compared with that in the early log phase. The increase in the concentration of total cytochrome is not accompanied by an increase in the respiration rate of the cells. Both cytochrome b and cytochrome c are located in the particulate fraction of the cells and are not fully reducible by succinate alone. 相似文献
66.
Among diploid Lathyrus species a threefold variation in nuclear DNA amount is attributable to differences in the amount of repetitive DNA. Cross reassociation among repetitive and among non-repetitive DNA fractions from different species shows substantial divergence in DNA composition. The divergence in base composition is correlated with nuclear DNA amount. The degree of divergence is of the same order of magnitude in both the repetitive and nonrepetitive fractions. 相似文献
67.
Naturally occurring antigenic variants of visna virus isolated from two persistently infected sheep have been compared using RNAase T1 fingerprint analysis of the viral RNAs. All the viruses examined have oligonucleotide changes in the 3′-terminal region of the viral genome and many of the alterations are common among the variants of both sheep. There is progressive accumulation of point mutations in the 3′-terminal region of antigenically altered viruses isolated from persistently infected animals. In addition, antigenic variants isolated independently from another sheep contain the same altered oligonucleotides; the nucleotide sequences of these oligonucleotides are identical. These data strongly suggest that the alterations observed in the nucleotide sequence of the variants are related to the change in their antigenic character. 相似文献
68.
Summary The effects of anthraquinones and some other quinonoid and phenolic compounds on mineralization of urea N in soils were studied by estimating the influence on urease activity and nitrification. Anthraquinones did not affect the mineralization of urea N but 1,4-naphthoquinone; 2-methyl-1,4-naphthoquinone; 2–3-dichlorohydroquinone; 4,6-di-tert.butyl-o-benzoquinone; 4-tert.butylpyrocatechol and 4,6-di-tert.butylpyrocatechol inhibited urease activity and nitrification. The hydrolysis of urea (100 ppm) was not prevented by partial reduction in urease activity. The effective substances also inhibited dehydrogenase activity. 相似文献
69.
70.
L J Thal M H Makman H S Ahn R K Mishra S G Horowitz B Dvorkin R Katzman 《Life sciences》1978,23(6):629-633
Studies of displacement by agonist and antagonist drugs of 3H-spiroperidol binding in brain regions of and rhesus monkeys revealed one type of receptor in caudate nucleus and a second type of receptor in both frontal and anterior limbic cortex. Compared with caudate, the cortical regions were more sensitive to clozapine and loxapine, equally sensitive to fluphenazine and relatively less sensitive to haloperidol. Also, the cortical regions were insensitive to molindone. Parallel studies using the dopamine-stimulated adenylate cyclase have demonstrated three types of receptors, one in caudate, a second in frontal cortex, and a third in anterior limbic cortex. In each region studied, relative sensitivities to drug using these two methods differed, suggesting that in each of these regions only a relatively small portion of 3H-spiroperidol receptors are coupled to adenylate cyclase. 相似文献