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141.
Roche Susceptibility Test (RST) Medium represents the most completely optimized and convenient fully defined medium described. It requires no post-autoclaving supplementation with vitamins, supports good growth of all common aerobic and anaerobic pathogens and may be used as a broth or agar gel on which the swarming of Proteus spp. is virtually eliminated. The broth as a superior buffering capacity to most complex media and an osmolality and pH close to those of human serum. RST is highly satisfactory for the susceptibility testing of commonly used antibiotics and meets the requirements of the National Committe for Clinical Laboratory Standards of the U.S.A. in almost every respect.  相似文献   
142.
143.
Peanut agglutinin (PNA), a lectin specific for terminal d-galactosyl residues, was found to react with embryonal carcinoma cells, but not with their differentiated derivatives. Receptors for PNA were detectable at the surface of all cells of the quasinullipotent F9 line and on only 50% of the multipotent PCC3/A/1 line. The fraction of the PCC3/A/1 population which expresses the F9 antigen was found to be included in the subpopulation carrying the PNA receptors. PNA+ and PNA? subpopulations of PCC3/A/1 were separated by a PNA-mediated reversible agglutination of PNA+ cells with rabbit erythrocytes. These subpopulations were essentially F9+ and F9?, respectively.  相似文献   
144.
We have developed a cytoenzymological method for localizing DNA polymerase activities in situ and for studying their responses to various chemical agents or environmental conditions. The incubation mixtures and the stimulatory or inhibitory agents added to these media were defined with reference to in vitro biochemical tests used to detect and to characterize DNA polymerases- or - found in eukaryotic cells. This method has already been used to study DNA polymerase activities during cell differentiation or cell senescence. Apart from two exceptions found with lower organisms, the nuclear DNA polymerase activity was always higher under conditions which favoured the in vitro expression of DNA polymerase- rather than DNA polymerase-. — In the various cell types studied, the cellular DNA polymerase activities were almost exclusively found in the nuclei. It is hoped that this methodology will be useful for obtaining more complete biochemical data on the intracellular localization of various DNA polymerases.  相似文献   
145.
DNA polymerase activity was extracted from testis cells of the dogfish Scyliorhinus caniculus. On a sucrose gradient, two main peaks could be separated, corresponding to DNA polymerases beta (3.8 S) and alpha (7.5 S). DNA polymerase gamma could also be detected when poly(A) . (dT)12 was used as template. The properties of alpha and beta polymerases of this primitive vertebrate were similar to those generally described, especially in mammals. The beta enzyme was highly sensitive to N-ethylmaleimide, however, and could use poly(dT) . poly(A) as template. Polymerase alpha was present in spermatogonia, spermatocytes and spermatids. Activity was maximal in spermatocytes. DNA polymerase beta was present in all testis cells with similar activities in spermatogonia and spermatocytes. Decreased activities were observed during spermiogenesis. Some activity remained associated with the chromatin fraction of mature sperm cells.  相似文献   
146.
A number of novel, aryl and aralkyl d-mannopyranosides and 1-thio-d-mannopyranosides were synthesized for evaluation of insulin-like and insulin-antagonistic properties. The substituted-phenyl α-d-mannopyranosides were prepared by the general procedure of Helferich and Schmitz-Hillebrecht, the substituted-phenyl 1-thio-α-d-mannopyranosides by a method corresponding to the Michael synthesis of aromatic glycosides, and the aralkyl 1-thio-α-d-mannopyranosides by aralkylation of 2,3,4,6-tetra-O-acetyl-1-thio-α-d-mannopyranose (15) and subsequent O-deacetylation. Compound 15 was obtained by basic cleavage of the amidino group in 2-S-(tetra-O-acetyl-α-d-mannopyranosyl)-2-thiopseudourea hydrobromide, the product of the reaction of tetra-O-acetyl-α-d-mannosyl bromide with thiourea. Benzyl 1-thio-β-d-mannopyranoside, obtained by reaction of the sodium salt of 1-thio-β-d-mannopyranose with α-bromotoluene, and benzyl 1-thio-α-l-mannopyranoside were also synthesized, in order to assess the stereospecificity of the biological activities measured.  相似文献   
147.
Abstract— The affinity of the fucose-binding lectin from Lotus tetragonolobus for fuco-oligosaccharides accumulating in the brain and other tissues of a patient with fucosidosis was studied by two methods: by inhibition of the co-precipitation of the lectin with porcine stomach mucin and by one-step affinity chromatography on a column of the lectin bound to Sepharose-4B. Both methods indicated that the lectin had greater affinity for the disaccharide Fuc(α, 1-6)GlcNAc than for either the main fucosidosis storage material in brain, a fuco-dekasaccharide, or the heterogeneous fuco-glycopeptide fractions obtained from normal human and rat brain glycoproteins. Our results suggest that the fucose residue linked α(1-6) to the N -acetylglucosamine residue involved in the N -glycosidic linkage to asparagine is not available to the lectin in the intact N -glycosidic chains of normal brain glycopeptide fractions and that the lectin has poor affinity for the Fuc(α, 1-3)Glc N Ac linkage in rat brain glycoproteins.  相似文献   
148.
The number of Rous viral genomes in the cellular DNA from two subclones (RS2/3, RS2/6) derived from the same clone of hamster BHK-21 cells transformed by Rous sarcoma virus was determined by hybridization with viral complementary DNA made in vitro, and the capacity of the cellular DNA to infect (transfect) chicken embryo fibroblasts was compared before and after shearing this DNA to about the size of the provirus (6 x 10(6) to 7 x 10(6) daltons). The two subclones differed widely both in their capacity to give rise to virus (inducibility) after fusion with chicken embryo fibroblasts and in level of expression of viral proteins. It was shown that cells of both subclones contain a single copy of Rous DNA and yield infectious DNA. However, whereas transfection of chicken embryo fibroblasts was successful with both unsheared (>/=18 x 10(6) daltons) and sheared DNA from the most inducible subclone (RS2/3 subclone), which also expresses viral proteins to an appreciable amount, transfection with DNA from the least inducible subclone (RS2/6 subclone), in which viral proteins are not expressed, succeeded only with sheared DNA. It was then about as successful as with sheared or unsheared RS2/3 DNA. The lack of infectivity of unsheared RS2/6 DNA may be explained by the hypothesis proposed by Cooper and Temin (G. M. Cooper and H. T. Temin, J. Virol. 17:422-430, 1976) to explain the lack of infectivity of DNA from certain chicken cells producing spontaneously low amounts of RAV-0 and resistant to exogenous RAV-0 infection, that is, that the viral genome (proviral DNA) is linked to a cis-acting control element which blocks its expression. This linkage might originate, in RS2/6 cells, from translocation of cellular DNA containing the single proviral copy.  相似文献   
149.
The effect of formate and of various electron acceptors—fumarate, aspartate, or nitrate—on the growth of 36 catalase-producingCampylobacter strains was quantitatively investigated in a semisynthetic medium, under aerobic (5% oxygen, 10% carbon dioxide, 85% nitrogen) or anaerobic (10% carbon dioxide, 90% nitrogen) conditions. Under anaerobic conditions, 24 strains ofC. jejuni failed to grow, or grew poorly, in the presence of fumarate, whereas ten strains ofC. fetus subsp.fetus and two strains ofC. fetus subsp.venerealis grew abundantly, rather better than under aerobic conditions. The quantitative differences of growth yields were very significant between the two species with fumarate, but less pronounced with aspartate or nitrate. The activity of fumarate-reductase inC. fetus was substantiated by identification of relevant metabolites by gas liquid chromatography and by mass spectrometry. The anaerobic fumarate respiration in the genusCampylobacter has taxonomic implications.  相似文献   
150.
The mainly neotropical genus Calliandra Benth. (Leguminosae–Mimosoideae–Ingeae) is reported for the first time as native in continental Africa. There are two species known, C. gilbertii Thulin & Hunde sp. nov. in E Kenya and Somalia and C. redacta (J. H. Ross) Thulin & Hunde comb. nov. in South Africa near the Namibia border. On pollen morphological grounds they are supposed to be most related to certain neotropical species but the pollen does not agree entirely with any previously known group of the genus. The distribution of C gilbertii and C. redacta stresses the phytogeographical link between the arid zones of northern and southern Africa.  相似文献   
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