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An examination of applicants to Canadian medical schools for 1966-67 revealed that 4534 applications were received for the approximately 974 available places. The number of Canadian applications was 2866 and these were made by 1815 individual applicants, an increase of 48 over 1965-66. United States applicants declined from 1143 to 1013.Evaluations made by the schools concerning the acceptability of the Canadian applicants disclosed that 55 applicants who rated as “acceptable” by one or more schools failed to gain admission to any medical school in 1966-67 (as compared to 36 in 1965-66). However, of those applicants who did find a place 76 were evaluated as “marginal” or “unacceptable”, while another 126 were rated as “acceptable” by one school but “marginal” and/or “acceptable” by one or more other schools.These results were interpreted to imply that the Canadian medical schools were still experiencing difficulty in attracting well-qualified applicants for study in medicine. 相似文献
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Clare M. O'Connor Bonnie J. Germain Kathleen M. Guthrie Dana W. Aswad Clarke F. Millette 《Molecular reproduction and development》1989,22(3):307-319
An antiserum prepared against the purified protein carboxyl methltransferase (PCMT) from bovine brain has been used to compare testicular and ovarian levels of the enzyme and to study the regulation of PCMT concentrations during spermatogenesis. The PCMT, which specifically modifies age-damaged aspartyl residues, is present at a significantly higher concentration in mature mouse testis than in ovary. However, the PCMT is present at nearly equal concentrations in extracts of germ cell-deficient ovaries and testes obtained from mutant atrichosislatrichosis mice. In normal testis, the concentration of the PCMT increases severalfold during the first 4–5 weeks after birth, paralleling the appearance and maturation of testicular germ cells. Both immunochemical and enzymatic measurements of PCMT specific activities in purified spermatogenic cell preparations indicate that PCMT levels are twofold and 3.5-fold higher in round spermatids and residual bodies, respectively, than in pachytene spermatocytes. The results are consistent with the enhanced synthesis and/or stability of the PCMT in spermatogenic cells and with the continued translation of the PCMT during the haploid portion of spermatogenesis. The relatively high levels of PCMT in spermatogenic cells may be important for the extensive metabolism of proteins accompanying spermatid condensation or for the repair of damaged proteins in translationally inactive spermatozoa. 相似文献
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Inhibition of in Vitro Pollen Tube Growth by Isolated S-Glycoproteins of Nicotiana alata 总被引:9,自引:6,他引:3 下载免费PDF全文
Pollen from three S-genotypes of Nicotiana alata was grown in vitro in the presence of S-glycoproteins isolated from styles of the same three genotypes. Pollen germination was not affected by the presence of the S-glycoproteins, but pollen tube growth of all genotypes was inhibited. S2 pollen was preferentially inhibited by the S2-glycoprotein and S3 pollen by the S3-glycoprotein. The S6-glycoprotein preferentially inhibited growth of both S2 and S6 pollen over S3 pollen. Heat treatment dramatically increased the inhibitory activity of the S-glycoproteins as inhibitors both of pollen germination and tube growth; after heat treatment, S-allele specificity of pollen tube inhibition was not detected. 相似文献
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A common theme in the amino acid sequences of actin and many actin-binding proteins? 总被引:9,自引:0,他引:9
The amino acid sequences of several actin regulatory proteins have recently been determined. Do these proteins function by mimicking actin-actin interaction sites? 相似文献
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Studies on schistosome protective immune responses have focused mainly on antigens of the parasite's syncytial surface. One of the characterized schistosome antigens, a 24-kDa glycoprotein, has been considered important in mechanisms of immune evasion by the parasites. In the present study, using affinity-purified antibodies to the 24-kDa protein for immunofluorescence and immunoelectron microscopy, we demonstrated an association of the 24-kDa antigen with the discoid bodies (the major syncytial inclusion bodies; DBs) and the surface membrane complex (most likely the apical plasma membrane) of adult Schistosoma mansoni. This is consistent with previous observations that the 24-kDa antigen appeared to be localized to the syncytial membrane and DB fractions. The present results also support the suggestion that the DBs are the precursor organelles of the apical plasma membrane. 相似文献