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101.
Stable expression of two variable surface glycoproteins by cloned Trypanosoma equiperdum 总被引:5,自引:0,他引:5
African trypanosomes are thought to evade the host immune system by periodically changing their variable surface glycoprotein (VSG). VSG genes are activated by a complex process involving the duplicative transposition of silent basic copy genes to one of several expression sites. These expression-linked copies (ELCs) of the VSG genes are also subject to regulation within expression sites by as yet unknown mechanisms. It is generally assumed that trypanosomes can express only one VSG gene at a time. Nevertheless, the finding that they contain multiple VSG gene expression sites suggests that multiple expression is possible. We show here that Trypanosoma equiperdum can stably express two VSG genes in a simple axenic culture system and that both antigens are present on the cell surface. The two antigens do not co-cap or form heterodimers. Their corresponding genes show no cross-hybridization and are situated in different telomere-linked expression sites. Northern blot analysis reveals that both genes are active in the double expressors. 相似文献
102.
Zusammenfassung Kalium erhöht die Bildung von markiertem Noradrenalin aus markiertem Tyrosin im isolierten Vas deferens. Es wird angenommen, dass dieser Effekt auf eine Steigerung der Tyrosin-Hydroxylase zurückzuführen ist. 相似文献
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Summary In cold-adapted guinea pigs, increased amounts of arginine-vasopressin (AVP) immunoreactive material could be visualized in neurons of the supraoptic and paraventricular nucleus, in fibers projecting to the neurohypophysis and in fiber terminals in the ventral lateral septum and in the amygdala. In warm-adapted animals the reactivity to AVP antiserum was poor in all neuronal structures examined. High AVP-immunoreactivity was accompanied by a reduced febrile response to bacterial pyrogen in cold-adapted guinea pigs. 相似文献
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L. Kohidai J. Barsony J. Roth S. J. Marx 《Cellular and molecular life sciences : CMLS》1992,48(5):476-481
We studied rapid changes in location of cyclic GMP inTetrahymena pyriformis. Insulin caused cGMP localization in cilia and near the plasma membrane (0.5–1 min). Later (1–5 min) cGMP localization was diffuse in cytoplasm with perinuclear accentuation. Inactive insulin analogs did not elicit these changes. 相似文献
109.
The genome of the model beetle and pest Tribolium castaneum 总被引:6,自引:0,他引:6
Tribolium Genome Sequencing Consortium Richards S Gibbs RA Weinstock GM Brown SJ Denell R Beeman RW Gibbs R Beeman RW Brown SJ Bucher G Friedrich M Grimmelikhuijzen CJ Klingler M Lorenzen M Richards S Roth S Schröder R Tautz D Zdobnov EM Muzny D Gibbs RA Weinstock GM Attaway T Bell S Buhay CJ Chandrabose MN Chavez D Clerk-Blankenburg KP Cree A Dao M Davis C Chacko J Dinh H Dugan-Rocha S Fowler G Garner TT Garnes J Gnirke A Hawes A Hernandez J Hines S Holder M Hume J Jhangiani SN Joshi V Khan ZM 《Nature》2008,452(7190):949-955
Tribolium castaneum is a member of the most species-rich eukaryotic order, a powerful model organism for the study of generalized insect development, and an important pest of stored agricultural products. We describe its genome sequence here. This omnivorous beetle has evolved the ability to interact with a diverse chemical environment, as shown by large expansions in odorant and gustatory receptors, as well as P450 and other detoxification enzymes. Development in Tribolium is more representative of other insects than is Drosophila, a fact reflected in gene content and function. For example, Tribolium has retained more ancestral genes involved in cell-cell communication than Drosophila, some being expressed in the growth zone crucial for axial elongation in short-germ development. Systemic RNA interference in T. castaneum functions differently from that in Caenorhabditis elegans, but nevertheless offers similar power for the elucidation of gene function and identification of targets for selective insect control. 相似文献
110.
Park S Park SH Baek JY Jy YJ Kim KS Roth J Cho JW Choe KM 《Cellular and molecular life sciences : CMLS》2011,68(20):3377-3384
Modification of nuclear and cytosolic proteins by O-linked N-acetylglucosamine (O-GlcNAcylation) is ubiquitous in cells. The in vivo function of the protein O-GlcNAcylation, however, is not well understood. Here, we manipulated the cellular O-GlcNAcylation level in Drosophila and found that it promotes developmental growth by enhancing insulin signaling. This increase in growth is due mainly to
cell growth and not to cell proliferation. Our data suggest that the increase in the insulin signaling activity is mediated,
at least in part, through O-GlcNAcylation of Akt. These results indicate that O-GlcNAcylation is one of the crucial mechanisms involved in control of insulin signaling during Drosophila development. 相似文献