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41.
Nielsen Johannes Vetner Max Holm Vagn Askjær Svend Aage Reske-Nielsen Edith 《Human genetics》1977,38(3):357-362
Summary A case of Meckel or Gruber syndrome is reported, together with a survey of the relevant literature of recent years (1971–1977), in reference to a probably autosomal recessive inheritance of this malformation. 相似文献
42.
Edith Zipser Geerat J. Vermeij 《Journal of experimental marine biology and ecology》1978,31(2):155-172
The Guamunian xanthids Carpilius maculatus (L.), C. convexus (Forskal), and Eriphia sebana (Shaw & Nodder), and the parthenopid Daldorfia horrida (L.), possess large master claws with molariform teeth than are used to crush the shells of hermit crabs and snails. These crabs typically sever the spire of their prey, or make a gash in the body whorl. They tend to employ sustained pressure on the prey shell, and, except for Eriphia, rarely attack the outer lip, so that the outer lip of the shell typically remains undamaged, except in shells near the critical size, i.e., the maximum size of vulnerability to predation. Temperate species of Cancer (C. productus Randall and C. oregonensi Rathbun) may also crush shelled prey in the larger of their two claws, but more commonly they use both claws together in breaking open their victims. Sustained pressure is applied for only short periods by these crabs.Gastropod adaptations conferring resistance to crushing by crabs include a thick shell, narrow or otherwise small aperture, thickened outer lip, strong sculpture, and a low spire. Emphasis on these traits lowers the critical size of the prey, i.e., permits escape from cushing at a smaller size. An equatorward increase in the expression of the characteristics of crushing-resistance parallels an increase in crushing power of the crabs. 相似文献
43.
Edith Wallace Harold I. Calvin George W. Cooper 《Molecular reproduction and development》1983,7(4):377-387
Three successive generations of mice were fed a Torula yeast based Se-deficient diet with or without 0.1 ppm Se in the drinking water. The Se-deficient mice, in the course of three generations, showed a decrease in body weight, testis weight, epididymal weight, and sperm production. The percentage of morphologically abnormal sperm increased in successive generations. The majority of sperm defects were found in the midpiece region of the tail. Many of these aberrant sperm were motile. A progressive decrease in fertility was noted during the first two generations of Se deficiency. This system confirms the essential role of Se in spermatogenesis and provides a model for the evaluation of the primary effect of Se deprivation on the structural development of sperm. 相似文献
44.
Paula N. Friedman Edith H. Wang Karen Meerovitch Nahum Sonenberg Carol Prives 《Chromosoma》1992,102(1):S60-S66
We have characterized the effects of p53 on several biochemical activities of simian virus 40 (SV40) large tumor (T) antigen. While p53 induced a strong inhibition of the T antigen DNA helicase activity, surprisingly, its RNA helicase activity was stimulated. This supports the liklihood that the DNA and RNA helicase activities of T antigen reflect discrete functions. p53 did not significantly affect the ATP-dependent conversion of T antigen monomers to hexamers. However, the ability of these hexamers to assemble on a DNA fragment containing the viral origin was impaired by p53. Thus, these results suggest that p53 inhibits the function but not the formation of T antigen multimers. This conclusion was further supported by the observation that the addition of a purified p53:T antigen complex was as inhihitory as free p53 to the DNA helicase activity of free T antigen. Thus our data indicates that the targets of p53 inhibition are the functional units of T antigen, namely the hexamers. 相似文献
45.
Receptor choice determinants in the envelope glycoproteins of amphotropic, xenotropic, and polytropic murine leukemia viruses. 总被引:46,自引:35,他引:11 下载免费PDF全文
The envelope glycoproteins (SU) of mammalian type C retroviruses possess an amino-terminal domain of about 200 residues, which is involved in binding a cell surface receptor. In this domain, highly conserved amino acid sequences are interrupted by two segments of variable length and sequence, VRA and VRB. We have studied the role of these variable regions in receptor recognition and binding by constructing chimeric molecules in which portions of the amino-terminal domains from amphotropic (4070A), xenotropic (NZB), and polytropic (MCF 247) murine leukemia virus SU proteins were permuted. These chimeras, which exchanged either one or two variable regions, were expressed at the surface of replication-defective viral particles by a pseudotyping assay. Wild-type or recombinant env genes were transfected into a cell line producing Moloney murine leukemia virus particles devoid of envelope glycoproteins in which a retrovirus vector genome carrying an Escherichia coli lacZ gene was packaged. The host range and sensitivity to interference of pseudotyped virions were assayed, and we observed which permutations resulted in receptor switch or loss of function. Our results indicate that the determinants of receptor choice are found within the just 120 amino acids of SU proteins. Downstream sequences contribute to the stabilization of the receptor-specific structure. 相似文献
46.
Purification of human C3b inactivator by monoclonal-antibody affinity chromatography 总被引:24,自引:5,他引:19 下载免费PDF全文
Li-min Hsiung A. Neil Barclay Malcolm R. Brandon Edith Sim Rodney R. Porter 《The Biochemical journal》1982,203(1):293-298
Monoclonal antibody has been obtained to the human complement control protein C3b inactivator after immunization of mice with the enzyme prepared by conventional methods. Antibody from ascitic fluid was purified and coupled to Sepharose-CL-4B to give a specific affinity column, which was used to isolate C3b inactivator from human serum in 70% yield. The product was characterized by size, chain structure, amino acid analysis and proteolytic activity. 相似文献
47.
Three forms of glutamate dehydrogenase have been isolated from developing soybean seed. Their intracellular locations could not be determined directly because organelles and marker enzymes showed abnormal distribution on sucrose density gradient fractionation. By analogy with enzymes from other parts of the plant, glutamate dehydrogenase 2 was shown to be located in chloroplasts and glutamate dehydrogenase 3 in mitochondria. Glutamate dehydrogenase 1 could not be located in this way because it is found only in the seed. The three enzymes are similar in pH optima, molecular weight and substrate specificity with respect to 2-oxoglutarate and l-glutamate. The mitochondrial enzyme is specific for NAD+. The chloroplast enzyme shows low activity with NADP+ relative to NAD+ but uses NADPH readily in the aminating direction. Glutamate dehydrogenase 1 is active with both nucleotides and is the only form to show substantial deaminating activity with NADP+. Glutamate dehydrogenases 1 and 2 are activated and stabilized by glutathione and 2-mercaptoethanol whereas enzyme 3 is unaffected. No significant metabolic control of any of the enzymes could be detected. Malate, citrate, adenine nucleotides and long-chain fatty acyl CoA derivatives gave slight inhibition at high concentrations. Amino acids had no effect on activity. A possible role for the enzyme characteristic of the developing seed is discussed in relation to nutrient supply during the accumulation of reserve materials in the seed. 相似文献
48.
Marc Uzan Renée Favre Edith Gallay Lucien Caro 《Molecular & general genetics : MGG》1981,182(3):462-470
Summary Eight ilvC transducing phages generated from E. coli K12 secondary site lysogens have been analysed genetically and physically. Two of them carry, in addition, the rho gene and its promotor region, but not the cya gene. The ilvO603 mutation has been located between ilvG and ilvE. Electrophoretic analysis of the proteins synthesized by these phages in a system of UV irradiated cells allowed us to assign molecular weights of 55000 and 66000 daltons to the ilvC and the ilvD gene products, respectively, and to show that an ilvG-encoded polypeptide of 60000 daltons is made from an ilvO
- but not from an ilvO
+ phage. The expression of the ilvG gene is discussed in the light of the recent finding of a promoter-attenuator region lying upstream to ilvG. Finally, we have found that one of the ilv phages does not have the classical structure of a transducing phage. 相似文献
49.
Zusammenfassung Der Waldrapp verfügt als soziale Vogelart über Verhaltensweisen des Gruppen- wie Paarkontaktes, die durch Veränderung von Körperumriß und Färbung unbefiederter Hautstellen verstärkt werden können: Grüßen, Imponieren, Aggressivverhalten (auch bei Nestlingen), Beschwichtigen, soziale Körperpflege, Kopula, Nestbau-Verhalten, Paarsitzen. Für das Zusammenspiel der Kolonie wichtig sind Grüßen, verschiedene Formen des Imponierens und ritualisierte Aggressionshandlungen. Das Fortpflanzungsgeschehen synchronisieren soziale Gefiederpflege, Kopulationen (bzw. Scheinkopulae) und Nestbauhandlungen. Das Paarsitzen, besonders deutlich außerhalb der Brutperiode, zeigt vermutlich Monogamie an.Das Lautrepertoire, eintönig für das menschliche Ohr, ist individuell variabel.Eine Besonderheit der Waldrappe ist auch die Nestlings-Aggressivität. Nestgeschwister trachten, einander durch Schnabelhiebe in eine Beschwichtigungshaltung zu drängen und so am Betteln zu hindern. Das Verhalten erlischt bei Erreichen eines Gewichtes von ca. 800 g, zugleich mit dem Abflachen der Wachstumskurve. Da Waldrappe ab dem ersten Ei brüten, überleben untergewichtige Letztgeschlüpfte (Nesthäkchen) bei ausreichendem Nahrungsangebot aufgrund ihrer länger anhaltenden Aggressivität.
Social behaviour of the Bald IbisGeronticus eremita — observations at the Alpenzoo, Innsbruck
Summary As a social bird the Bald Ibis shows behaviour patterns for group contact as well as for pair contact: greeting, display, aggressive behaviour of adults and sibling competition, appeasement behaviour, social preening, nesting behaviour, and Paarsitzen (spatial bond). Some of them may be reinforced by changing body-shape and colour of unfeathered skin. Greeting, some forms of display and ritualized aggressions are important for normal intraspecific interactions. Social preening, copulations (false copulae also) and nesting behaviour do not only stimulate the partner, they also synchronize activity within a colony. Paarsitzen might indicate longer lasting monogamy. The vocal inventory is rather uniform, but some calls may vary individually. — The Bald Ibis shows a strong sibling competition. Siblings force to prevent each other to gape by violent pecking and thus releasing appeasement behaviour. Sibling competition stops with about 800 g at the end of the period of rapid body growth. As the Bald Ibis is breeding with the first egg, this behaviour may allow survival of the runt because of its longer lasting aggressivity when there is sufficient food supply.相似文献
50.