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排序方式: 共有1006条查询结果,搜索用时 15 毫秒
911.
P. G. Martin 《Cellular and molecular life sciences : CMLS》1959,15(1):34-35
Résumé La transmission de l'albinisme panaché deBrassica oleracea L. ne dépend que d'un seul facteur. Chez les hétérozygotes ce caractère apparaît à basse température (7°C), mais pas à haute température (21°C). Chez les homozygotes le caractère se manifeste probablement toujours, tout en restant peu prononcé à des températures plus élevées. Ainsi il y a une inversion du caractère dominant avec changement de température. 相似文献
912.
913.
Vertebrate development. Limbs: a pattern emerges 总被引:1,自引:0,他引:1
914.
915.
Isolation of an HTLV-III-related retrovirus from macaques with simian AIDS and its possible origin in asymptomatic mangabeys 总被引:51,自引:0,他引:51
M Murphey-Corb L N Martin S R Rangan G B Baskin B J Gormus R H Wolf W A Andes M West R C Montelaro 《Nature》1986,321(6068):435-437
Acquired immune deficiency syndrome (AIDS) has become a worldwide epidemic, so the development of vaccines and antiviral agents effective against the causative agent, human T-lymphotropic virus type III (HTLV-III), is vital. This work would be greatly simplified if a suitable animal model could be developed. Here we report the isolation of an HTLV-III-related retrovirus, STLV-III/Delta, from rhesus macaques (Macaca mulatta) with transmissible simian AIDS (SAIDS) and from asymptomatic sooty mangabeys (Cercocebus atys). SAIDS was initially diagnosed in several macaques previously inoculated with tissue homogenates of mangabey origin. Western blot analysis of both the mangabey and macaque sera demonstrated the presence of antibody cross-reactive primarily with the HTLV-III proteins p24 and p61. In a related experiment, analysis of these same sera revealed simian antibody to STLV-III/Delta proteins similar, but not identical, to those of HTLV-III with estimated relative molecular masses (Mrs) of 16,000 (16K), 26K, 35K, 45K, 60K and 110K. Infection of the mangabey, an African primate, with an HTLV-III-related virus may provide a clue to the origin of HTLV-III in humans. The apparent difference in susceptibility to SAIDS-like disease between infected macaques and mangabeys suggests that these species may respond differently to STLV-III infection. 相似文献
916.
917.
Comparative effects of ouabain, natriuretic factor and ammonium chloride in the toad urinary bladder
Electrical changes and direct effects on Na-K ATPase activity induced by an endogenous digitalis-like natriuretic factor (NF), NH4Cl and ouabain were studied in toad bladders. NF inhibited the SCC and the Na-K ATPase activity in a similar manner to ouabain, but induced a greater increase in calculated direct current resistance (R) (p less than 0.05). NH4Cl was a weak inhibitor of Na-K ATPase activity, although it produced steeper SCC inhibition slopes than those observed with ouabain or NF (p less than 0.01). The data suggested the same mechanism of action of NF and ouabain on the sodium pump, with an additional effect of the former on apical sodium permeability of the cells and/or closure of paracellular routes leading to an increased tissue resistance. In contrast, the effects of NH4Cl were mostly compatible with intracellular inhibition of apical sodium entry into the cell. 相似文献
918.
Evolutionary dynamics on graphs 总被引:1,自引:0,他引:1
Evolutionary dynamics have been traditionally studied in the context of homogeneous or spatially extended populations. Here we generalize population structure by arranging individuals on a graph. Each vertex represents an individual. The weighted edges denote reproductive rates which govern how often individuals place offspring into adjacent vertices. The homogeneous population, described by the Moran process, is the special case of a fully connected graph with evenly weighted edges. Spatial structures are described by graphs where vertices are connected with their nearest neighbours. We also explore evolution on random and scale-free networks. We determine the fixation probability of mutants, and characterize those graphs for which fixation behaviour is identical to that of a homogeneous population. Furthermore, some graphs act as suppressors and others as amplifiers of selection. It is even possible to find graphs that guarantee the fixation of any advantageous mutant. We also study frequency-dependent selection and show that the outcome of evolutionary games can depend entirely on the structure of the underlying graph. Evolutionary graph theory has many fascinating applications ranging from ecology to multi-cellular organization and economics. 相似文献
919.
Oaks JL Gilbert M Virani MZ Watson RT Meteyer CU Rideout BA Shivaprasad HL Ahmed S Chaudhry MJ Arshad M Mahmood S Ali A Khan AA 《Nature》2004,427(6975):630-633
920.
Martin J Han C Gordon LA Terry A Prabhakar S She X Xie G Hellsten U Chan YM Altherr M Couronne O Aerts A Bajorek E Black S Blumer H Branscomb E Brown NC Bruno WJ Buckingham JM Callen DF Campbell CS Campbell ML Campbell EW Caoile C Challacombe JF Chasteen LA Chertkov O Chi HC Christensen M Clark LM Cohn JD Denys M Detter JC Dickson M Dimitrijevic-Bussod M Escobar J Fawcett JJ Flowers D Fotopulos D Glavina T Gomez M Gonzales E Goodstein D Goodwin LA Grady DL Grigoriev I Groza M Hammon N Hawkins T 《Nature》2004,432(7020):988-994