胶东地区西洋参营养元素含量研究

测定了胶东地区３～５年生西洋参中氨基酸和总皂甙含量的变化情况,结果显示：氨基酸含量侧根高于主根;在同龄参中１０月采收样品氨基酸含量最高;总皂甙含量依次为则根和须根＞叶＞主根＞茎。     

Atomic structure of an alphabeta T cell receptor (TCR) heterodimer in complex with an anti-TCR fab fragment derived from a mitogenic antibody.

Each T cell receptor (TCR) recognizes a peptide antigen bound to a major histocompatibility complex (MHC) molecule via a clonotypic alphabeta heterodimeric structure (Ti) non-covalently associated with the monomorphic CD3 signaling components. A crystal structure of an alphabeta TCR-anti-TCR Fab complex shows an Fab fragment derived from the H57 monoclonal antibody (mAb), interacting with the elongated FG loop of the Cbeta domain, situated beneath the Vbeta domain. This loop, along with the partially exposed ABED beta sheet of Cbeta, and glycans attached to both Cbeta and Calpha domains, forms a cavity of sufficient size to accommodate a single non-glycosylated Ig domain such as the CD3epsilon ectodomain. That this asymmetrically localized site is embedded within the rigid constant domain module has implications for the mechanism of signal transduction in both TCR and pre-TCR complexes. Furthermore, quaternary structures of TCRs vary significantly even when they bind the same MHC molecule, as manifested by a unique twisting of the V module relative to the C module.     

人蚤(Pulex irritans Linn.)及猫栉头蚤(Ctenocephalides felis Bouché)小志

人蚤及猫栉头蚤是家庭内常见的两种跳蚤。它们的分布遍及全世界。关于它们的调查和研究,世界各地曾有很多报告。作者在北京(1950—51     

Identification and Phylogenetic Classification of <Emphasis Type="Italic">Pennisetum</Emphasis> (Poaceae) Ornamental Grasses Based on SSR Locus Polymorphisms

Pennisetum species are widely used as ornamental grasses and may be a valuable genetic resource for their breeding to broaden its genetic basis. At present, new ornamental Pennisetum cultivars are primarily bred via somaclone, which increases the number of variants. It is difficult to estimate whether the suspected variants are authentic in genetic features by morphological traits because of their many limitations. Moreover, although the phylogenetic classification of the Pennisetum genus has been approved in some morphological and cytological studies, genetic evidence is lacking. In the present study, we developed 15 specific simple sequence repeat (SSR) markers with a large amount of polymorphisms and strong distinguishing abilities for Pennisetum ornamental grasses using magnetic bead enrichment. These markers, together with the other 11 reported polymorphic SSRs, were further used for the identification of a broad collection of 55 Pennisetum samples, including nine original taxa and 46 suspected variants. After comparing the genetic characteristics between each variant and its corresponding original taxon, we verified 20 suspected variants that possess the potential to become new, commercially desirable cultivars. The nine original taxa and the 20 verified variants were identified based on the polymorphisms of six core loci, and unique molecular identities with 15 denary digits for each taxon were further established. The rationality of the traditional phylogenetic classification system of the Pennisetum genus was further verified using 147 polymorphic alleles. The present study promotes the protection, registration, breeding, and international communication of Pennisetum ornamental grasses.     

Lactotransferrin is the major estrogen inducible protein of mouse uterine secretions

Antibody to an estrogen inducible mouse uterine protein (Teng, C. T., Walker, M. P., Bhattacharyya, S. N., Klapper, D. G., DiAugustine, R. P., and McLachlan, J. A. (1986) Biochem. J. 240, 413-422) has been used to isolate cDNA to the messenger RNA. Analysis of the deduced primary structure and additional biochemical characterization indicates that the protein is lactotransferrin. An increase in the level of lactotransferrin mRNA of at least 300-fold can be induced in the mouse uterus by estrogen. In contrast, the mRNA is virtually undetectable in rat uterine tissue following estrogen administration. The estrogenic stimulation in mouse uterus contrasts with the known prolactin dependence in mammary gland.     

高糖膳食对大鼠载脂蛋白AⅠ、CⅡ和CⅢ基因表达的影响

 我们以Sprague-Dawley大鼠为实验对象,研究高糖膳食对大鼠肝脏及小肠载脂蛋白(apo)AⅠ、CⅡ和CⅢmRNA相对含量的影响。摄取高糖膳食6天后,大鼠空腹血清TG含量和胰岛素水平均显著升高,cAMP含量则显著下降。同时,用RNA斑点杂交技术分析表明,摄取高糖膳食6天后,肝脏apoAⅠCⅡ和CⅢmRNA相对含量均显著下降(P<0.01,P<0.05);小肠apoAⅠ和CⅡmRNA相对含量也显著下降(P<0.05,P<0.01),但小肠apoCⅢmRNA相对含量无改变。