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101.
The VP1 coat protein of FMDV strain A Venceslau (Aven) consists of 213 amino acid residues. Serum neutralization tests demonstrated that strain Aven is closely related to strain A Argentina/79 (A79) but significantly different from strain A24 Cruzeiro (A24). There is a strong correlation between the amino acid sequences and the serological data. Nucleotide and amino acid sequence analyses of VP1 showed that serologically related viruses (Aven and A79) differ less in this region of the genome than those of serologically distinct viruses (Aven vs. A24). The most significant variation between Aven and A24 occurs at amino acid positions 43 to 46, in which all four residues are different. 相似文献
102.
Oren Zinder Philip G. Hoffman William M. Bonner Dr Harvey B. Pollard 《Cell and tissue research》1978,188(2):153-170
Summary A highly enriched fraction of plasma membranes from the bovine adrenal medulla has been isolated by differential and sucrose gradient centrifugation. The membranes were found to occur as 0.1–0.5 diameter vesicles and to equilibrate at a density of 1.13–1.14 g/ml. This fraction was characterized by 4-fold elevated levels of adenylate cyclase and 20-fold elevated levels of 5-nucleotidase. Secretory vesicle membranes, isolated by repeated hypotonie and hypertonic shocks of whole vesicles, were found to equilibrate between d = 1.08 and d = 1.12 on a sucrose density step gradient. These membranes were highly enriched in cytochrome b562 and dopamine--hydroxylase. Proteins in the two membranes were compared by SDS gel electrophoresis. All protein size classes found in the vesicle membrane fraction were also represented in the plasma membrane fraction, though in different proportions on the basis of staining intensity. The plasma membrane fraction contained prominent bands co-migrating with the - and -bands of tubulin, as well as a component co-migrating with actin. These bands were absent from the vesicle membranes. Fingerprint analysis of stained bands from the membrane fraction demonstrated that the components were indeed tubulin and actin. The plasma membranes contained twice as much sialic acid residues as did the chromaffin granule membranes, but had only half the cholesterol content on a weight basis. The cholesterolphospholipid ratio in the plasma membranes was 0.63, while in the secretory vesicle membranes it was 1.04. These results show that plasma membranes and secretory vesicle membranes are functionally and structurally different.Supported, in part, by a stipend to O.Z. from The Grant Foundation, New York 相似文献
103.
The topologic arrangement of petiolar bundles varies within the length of the cottonwood petiole. Each petiolar bundle is formed by the subdivision and aggregation of acropetally differentiating subsidiary bundles in a predictable pattern. The subsidiary bundles provide vascular continuity between the stem and specific portions of the leaf lamina. Spot-labeling of individual veins with 14CO2, freeze substitution, and microautoradiography were used to establish the relation between the secondary veins of the lamina and the vasculature of the petiole. Within the petiole vasculature each subsidiary bundle was continuous with a specific portion of the lamina and seemed to have a separate function. Subsidiary bundles continuous with the central leaf trace were closely related functionally to the tip region of the lamina, while the subsidiary bundles continuous with the lateral leaf traces were functionally related to the middle and basal portions of the lamina. 相似文献
104.
Philip Serwer 《Analytical biochemistry》1980,101(1):154-159
A technique has been developed for embedding several agarose gels (running gels), each of a different agarose concentration, within a single 1.5% agarose slab. Equal portions of a sample were placed at the origin of each running gel and were simultaneously subjected to electrophoresis. Protein within the running gels was detected by staining with Coomassie blue; 0.2% gels were the least concentrated gels that were stained without gel breakage. Using the above technique, the dependence of electrophoretic mobility on agarose concentration has been measured for bacteriophage T7 capsids and a capsid dimer. 相似文献
105.
Yitzhak Stabinsky Philip Gottlieb Mati Fridkin 《Molecular and cellular biochemistry》1980,30(3):165-170
Summary Sixteen new analogs of the phagocytosis-stimulating peptide tuftsin have been synthesized. The biological activities of these synthetic peptides, in which either the C-terminal or both C- and N-terminals are chemically altered, were evaluated by studying their effects on the phagocytosis of heat-killed yeasts and on the reduction of the dye nitroblue tetrazolium by normal human polymorphonuclear leukocytes. The results demonstrate that the integrity of the guanidine side chain of arginine at position four of tuftsin is crucial for maximal activity. Modification, even in side chain length, of the guanidine leads to decreasing activity. Preservation of the positive charge of position four of tuftsin yields analogs possessing considerable activity. Simultaneous alterations of both C- and N-terminal results in diminishing activites. The results of this study are discussed in relation to the structural features of tuftsin. It appears that interaction between the carboxyl of Arg4 and the amino group of Thr1 which would indicate a specific conformation such as a 4 1 -turn are not favored. 相似文献
106.
Summary Desert populations of the evergreen dioecious shrub Simmondsia chinensis exhibit sex-related leaf and canopy dimorphisms not present in populations from more mesic coastal environments. Leaves on female shrubs have characteristically larger sizes, greater specific weights, and greater water-holding capacity than male leaves in desert habitats. In coastal scrub environments no significant difference is present, with leaf characteristics of both sexes similar to those of desert male shrubs. Desert female shrub canopies are typically relatively open with little mutual branch shading. In male shrubs canopies are more densely branched with considerable mutual shading of branches. Female plants allocate a greater proportion of their vegetative resources to leaves than do male plants. Considering total biomass, male plants allocate 10–15% of their resources (biomass, calories, glucose-equivalents, nitrogen, phosphorus) to reproductive tissues. Female allocation is dependent on seed set. At 100% seed set females would allocate 30–40% of their resources to reproduction, while female reproductive investment would equal that of males at approximately 30% seed set. Sexual dimorphism and the associated physiological characteristics in Simmondsia act as an alternative to differential habitat selection by male and female plants. Female plants respond to limited water resources in desert areas by increasing their efficiency in allocating limited resources to reproductive structures. 相似文献
107.
Philip Hershkovitz 《Primates; journal of primatology》1979,20(2):277-287
The two described subspecies of the emperor tamarin,Saguinus imperator imperator Goeldi andSaguinus imperator subgrisescens Lönnberg are defined and compared, the geographic range of each plotted. 相似文献
108.
Antibody prepared in I-E-subregion-incompatible strains (anti-A
e
s
:E
/k
) cross-reacts with I-A-subregion controlled A
b
: A
/b
and A
q
A
q
complexes. This cross-reaction defines a new I-region specificity designated Ia.50. The implications of this finding for the genetic origin of the I region and immuneresponse-gene function are discussed. 相似文献
109.
Henry R. Black Samuel O. Thier Philip F. Felig James F. Jekel Joseph Belsky James L. Bernene Everett Cooper Vincent A. De Luca Jr. Martin H. Floch Marvin Garrell Pasquale E. Perillie Robert L. Piscatelli George F. Thornton 《The Yale journal of biology and medicine》1977,50(6):637-644
In July, 1975, the Departments of Internal Medicine at the Yale University School of Medicine and eight community hospitals in southern and western Connecticut formed the Yale Affiliated Hospital Program (YAHP) in Internal Medicine. The YAHP provides a planned and focused program of continuing education for medical staff and housestaff at the affiliated hospitals. Six formats for the over 1,000 rounds, lectures, and conferences given annually are used. The members of the YAHP also cooperate in housestaff and faculty recruiting, evaluation of quality of care and evaluation of the process of continuing medical education itself. This report summarizes the organization, goals and future plans of the YAHP. 相似文献
110.
Summary The influence of a range of pesticides, lime and organic amendments on the level of soil ethylene was determined. Ethylene is important in soils because it can influence the growth of both plants and micro-organisms and thus influence soil fertility. The pesticides used, with the exception of fungicides, had a negligible influence on ethylene production. Fungicide treatment however, led to increased ethylene production. Similar, though more marked increases followed liming, and the addition of chitin, cellulose, urea and barley straw to soil. The results suggest that the action of fungicide in soils is due in part to the secondary production of ethylene following treatment. In the same way increased ethylene production following the addition of lime and organic amendments is likely to influence the activities of both saprophytic and plant pathogenic micro-organisms in the soil. re]19760726 相似文献