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61.
George Dunea 《BMJ (Clinical research ed.)》1985,290(6470):776-777
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Dr. William R. Usinger George C. Clark Ellen Gottschalk Stanley Holt Robert I. Mishell 《Current microbiology》1985,12(4):203-207
A Gram-negative, psychrophilic bacterium, designated GB-2, was isolated from fetal calf serum and analyzed for its morphological, physiological, and biochemical characteristics. Gliding motility, sensitivity to actinomycin D, the presence of the pigment flexirubin and cytochrome c, growth on a variety of carbohydrates, the production of acid fermentation products, and a 34.9 mol% guanine+cytosine (G+C) content of bacterial DNA indicate GB-2 to be a member either of the generaCytophaga orFlexibacter. Growth of GB-2 was optimized in a simple defined medium to facilitate isolation and characterization of bacterial products. Liquid growth of GB-2 resulted in the release of significant quantities of a macromolecule free of both endotoxin and protein into the growth supernatant, which activated the proliferation of murine lymphocytes. The relationship between this bacterium and its end-products to other species of theCytophaga/Flexibacter group is discussed. 相似文献
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George P. Barnes Richard G. Tollefsbol Warren A. Parker John F. Nelson 《Gerodontology》1986,5(2):129-134
Increased longevity and recently intensified emphasis on gerodontology mandate that dental students'exposure to clinical care of the elderly be enhanced. The extent to which individual students can be exposed to geriatric dental care depends on the availability of elderly patients to dental school clinics and the treatment needs of these patients. The purposes of this study were (1) to determine the dental treatment needs of geriatric patients who seek care at a dental school, and (2) to ascertain if differences exist between the needs of older versus relatively young geriatric patients. Data collected on 128 elderly patients during a three month period indicate that 57% of the aged were either edentulous at examination or treatment planned to become edentulous and receive two full dentures. The remaining 43% were treatment planned to remain dentulous and receive therapies other than full upper and lower dentures. More older geriatric patients required full dentures than their younger cohorts. More young elderly required prophylaxes, scalings, root planing therapy, dental restorations, and partial dentures. Additional to their denture requirements, aged patients appear to have sufficient non-prosthetic needs to allow for meaningful gerodontic experience by students. 相似文献
67.
Properties of Mutants in Galactose Taxis and Transport 总被引:29,自引:17,他引:12
beta-Methylgalactoside (mgl) permease mutants of Escherichia coli, which are defective in three genes, mglA, mglB, and mglC, were assayed for galactose taxis and galactose transport. The mglB product is the galactose-binding protein. Previous evidence, supported by our new findings, shows that the galactose-binding protein is the recognition component for galactose taxis as well as for galactose transport. Most mutants defective in mglB showed strong effects on both chemotaxis and transport; however, a couple showed effects chiefly on one process or the other, thus allowing a separation of chemotaxis and transport. The mglA and mglC products have not yet been identified, but they must be components of the galactose transport machinery since mutants defective in mglA or mglC, or both, showed strongly reduced transport. Although some of these mutants showed little chemotaxis, most gave close to wild-type chemotactic responses. Thus, transport is not required for galactose taxis. The bacteria detect changes in the fraction of binding protein associated with galactose, not changes in the rate of transport. 相似文献
68.
Does New Guinea cannibalism have nutritional value? 总被引:1,自引:0,他引:1
This paper examines the question of the nutritional value of cannibalism. Although other authors have concluded that the practice does not have such value, we argue that this cannot properly be determined except in the context of the total subsistence economy and local human ecology. The paper also presents a format for the empirical investigation of foodgetting and new ethnographic information about New Guinea cannibalism. Our major conclusion is that this practice does have nutritional value for certain human groups, specifically tropical peoples living at lowmedium population densities and exploiting a diverse range of animal foods. 相似文献
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Purification of human placental alkaline phosphatase. Salt effects in affinity chromatography 总被引:4,自引:3,他引:1
Human placental alkaline phosphatase was chromatographed on Sepharose derivatives of d- and l-phenylalanine, l-leucine, glycine, aniline and p-aminobenzoic acid in high concentrations of (NH(4))(2)SO(4). Retention on these columns was greatest at the highest concentrations of (NH(4))(2)SO(4). By using decreasing concentrations and changing the types of salts, elution was effected from each of the columns. The (NH(4))(2)SO(4)-mediated retention appeared to be related to the hydrophobic character of the substituted Sepharose, rather than to any specific binding site of the enzyme. It is suggested that this provides a way of controlling hydrophobic affinity chromatography. By use of chromatography on l-phenylalanine-Sepharose and of DEAE-Sephadex chromatography in the presence of Triton X-100 detergent, a preparation of highly purified (1000-fold) human placental alkaline phosphatase was obtained in 22% yield. 相似文献