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61.
Jean-Pierre Suzzoni 《Cell and tissue research》1972,128(3):426-437
Résumé Chez les Silphes et en particulier chez Phosphuga atrata, la glande de la spermathèque présente une structure particulière liée à la présence d'une intima cuticulaire tapissant la lumière de la glande. Elle comporte trois types cellulaires: les cellules sécrétrices, les cellules de l'épithélium sous-cuticulaire et les cellules-manchons. Les cellules sécrétrices de grande taille contiennent une invagination de la membrane cytoplasmique formant une «vacuole» extracellulaire bordée de microvillosités. Dans cette vacuole plonge l'extrémité, différenciée en ampoule poreuse, d'un canalicule de nature cuticulaire, qui véhicule la sécrétion jusqu'à la lumière de la glande. Le canalicule est élaboré par une cellule-manchon qui l'accompagne sur toute sa longueur sauf à son extrémité intravacuolaire.Ce type de glande, qui se retrouve chez de nombreux Insectes, y assurant des fonctions diverses (sécrétion odorifique, sécrétion de défense, sécrétion spermale, etc.), est susceptible de nombreuses variations.
Ultrastructure of the spermathecal accessory gland in Phosphuga atrata L. (coleoptera: silphidae)
Summary The spermathecal accessory gland in the female of Phosphuga atrata (Silphidae), exhibits a special structure which is due to the presence of a cuticular intima lining the lumen. The wall of the gland shows three cellular types: the secretory cells, the epithelial cells and the ductule carrying cells. Each large secretory cell contains a cavity formed by an invagination of the cytoplasmic membrane and lined by many microvilli. The secretory cell is connected with a cuticular ductule ending in the cavity of the glandular cell, in a porous organelle. This ductule, which carries the secretory material to the lumen, is surrounded by the ductule carrying cell.This type of integumentary gland is very common in insects, where it assumes various functions (attraction, defense, conservation of sperm, etc.) and its morphology varies considerably.相似文献
62.
63.
Among the different approaches used to define the function of a protein of interest, alteration and/or deletion of its encoding gene is the most direct strategy. Homologous recombination between the chromosomal gene locus and an appropriately designed targeting vector results in an alteration or knockout of the gene of interest. Homologous recombination is easily performed in yeast or in murine embryonic stem cells, but is cumbersome in more differentiated and diploid somatic cell lines. Here we describe an efficient method for targeting both alleles of a complex human gene locus in DG75 cells, a cell line of lymphoid origin. The experimental approach included a conditional knockout strategy with three genotypic markers, which greatly facilitated the generation and phenotypic identification of targeted recombinant cells. The vector was designed such that it could be reused for two consecutive rounds of recombination to target both alleles. The human DG75 cell line appears similar to the chicken DT40 pre B-cell line, which supports efficient homologous recombination. Therefore, the DG75 cell line is a favorable addition to the limited number of cell lines amenable to gene targeting and should prove useful for studying gene function through targeted gene alteration or deletion in human somatic cells. 相似文献
64.
Gilleron P Wlodarczyk N Houssin R Farce A Laconde G Goossens JF Lemoine A Pommery N Hénichart JP Millet R 《Bioorganic & medicinal chemistry letters》2007,17(19):5465-5471
A new series of FTase inhibitors containing a tricyclic moiety--dioxodibenzothiazepine or dibenzocycloheptane--has been designed and synthesized. Among them, dioxodibenzothiazepine 18d displayed significant inhibitory FTase activity (IC(50)=17.3 nM) and antiproliferative properties. 相似文献
65.
A mutation within the C-terminal domain of Sup35p that affects [PSI+] prion propagation 总被引:1,自引:0,他引:1
The epigenetic factor [PSI+] in the yeast Saccharomyces cerevisiae is due to the prion form of Sup35p. The N-terminal domain of Sup35p (N), alone or together with the middle-domain (NM), assembles in vitro into fibrils that induce [PSI+] when introduced into yeast cells. The Sup35p C-terminal domain (C), involved in translation termination, is essential for growth. The involvement of Sup35p C-terminal domain into [PSI+] propagation is subject to debate. We previously showed that mutation of threonine 341 within Sup35p C-domain affects translation termination efficiency. Here, we demonstrate that mutating threonine 341 to aspartate or alanine results in synthetic lethality with [PSI+] and weakening of [PSI+] respectively. The corresponding Sup35D and Sup35A proteins assemble into wild-type like fibrils in vitro, but with a slower elongation rate. Moreover, cross-seeding between Sup35p and Sup35A is inefficient both in vivo and in vitro, suggesting that the point mutation alters the structural properties of Sup35p within the fibrils. Thus, Sup35p C-terminal domain modulates [PSI+] prion propagation, possibly through a functional interaction with the N and/or M domains of the protein. Our results clearly demonstrate that Sup35p C-terminal domain plays a critical role in prion propagation and provide new insights into the mechanism of prion conversion. 相似文献
66.
67.
Ghassen Abid Yordan Muhovski Jean-Marie Jacquemin Dominique Mingeot Khaled Sassi André Toussaint Jean-Pierre Baudoin 《Plant Cell, Tissue and Organ Culture》2011,107(2):341-353
Two genotypes of common bean (Phaseolus vulgaris L.) were studied to determine the structural cause of seed abortion in this species. In the non-abortive control (wild-type,
cultivar BAT93), the histological analysis revealed a classical pattern of seed development and showed coordinated differentiation
of the embryo proper, suspensor, endosperm tissue and seed coat. In contrast, the ethyl methanesulfonate (EMS) mutant (cultivar
BAT93) showed disruption in the normal seed development leading to embryo abortion. Aborted embryos from these degenerate
seeds showed abnormalities in suspensor and cotyledons at the globular, heart, torpedo and cotyledon stages. Exploring the
feasibility of incorporating the available online bioinformatics databases, we identified 22 genes revealing high homology
with genes involved in Arabidopsis
thaliana embryo development and expressed in common bean immature seeds. The expression patterns of these genes were confirmed by
RT–PCR. All genes were highly expressed in seed tissues. To study the expression profiles of isolated genes during Phaseolus embryogenesis, six selected genes were examined by quantitative RT–PCR analysis on the developing embryos of wild-type and
EMS mutant plants. All selected genes were expressed differentially at different stages of embryo development. These results
could help to improve understanding of the mechanism of common bean embryogenesis. 相似文献
68.
Molecular systematics, character evolution, and pollen morphology of Cistus and Halimium (Cistaceae)
Laure Civeyrel Julie Leclercq Jean-Pierre Demoly Yannick Agnan Nicolas Qu��bre C��line P��lissier Thierry Otto 《Plant Systematics and Evolution》2011,295(1-4):23-54
Pollen analysis and parsimony-based phylogenetic analyses of the genera Cistus and Halimium, two Mediterranean shrubs typical of Mediterranean vegetation, were undertaken, on the basis of cpDNA sequence data from the trnL-trnF, and trnS-trnG regions, to evaluate limits between the genera. Neither of the two genera examined formed a monophyletic group. Several monophyletic clades were recognized for the ingroup. (1) The ??white and whitish pink Cistus??, where most of the Cistus sections were present, with very diverse pollen ornamentations ranging from striato-reticulate to largely reticulate, sometimes with supratectal elements; (2) The ??purple pink Cistus?? clade grouping all the species with purple pink flowers belonging to the Macrostylia and Cistus sections, with rugulate or microreticulate pollen. Within this clade, the pink-flowered endemic Canarian species formed a monophyletic group, but with weak support. (3) Three Halimium clades were recovered, each with 100% bootstrap support; all Halimium species had striato-reticulate pollen. Two Halimium clades were characterized by yellow flowers, and the other by white flowers. 相似文献
69.
70.
Fung EN Xia YQ Aubry AF Zeng J Olah T Jemal M 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(27):2919-2927
A liquid chromatography-full scan high resolution accurate mass spectrometry (LC-HRMS) method for quantifying prednisone and prednisolone in human plasma using a quadrupole time-of-flight mass spectrometer (Q-TOF) was developed. Plasma samples were extracted using a liquid-liquid extraction procedure. Full scan data were acquired in the TOF only mode and extracted ion chromatograms were generated post-acquisition with the exact masses of the analytes. The calibration range was 5-2500 ng/mL, with a Lower Limit of Quantitation (LLOQ) of 5 ng/mL. The assay accuracy was between 98.4% and 106.3%. The between-run (inter-day) and within-run (intra-day) precision were within 1.7% and 2.9%, respectively. The matrix effect was between 0.98 and 1.10 for the six different lots of human plasma evaluated. Pooled incurred samples were analyzed by the method and the results matched those obtained from an LC-MS/MS method. In addition, qualitative information on phospholipids, and other endogenous components were also extracted from the full-scan data acquired. 相似文献