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Summary A histological, histochemical and ultrastrucutral study of the pars intercerebralis (PI) has been made in Locusta migratoria.
The acellular neural lamella is made up of an elastic tissue and collagen fibrils. The cells of the perilemma contain numerous lysosome structures and lipid granules.Three different types of neurosecretory cells (NSC A, B and C) have been distinguished in the PI associated with giant neurons.The cells termed A and B seem not to have an activity cycle during the two last larval instars. At the moment of sexual maturity the NSC A show an important accumulation of neurosecretory material and their number increases at the expense of the NSC B. The NSC A, which are characterized by a highly developped endoplasmic reticulum, contain numerous secretory granules which appear to be individualized in the Golgi complex in three different ways. The NSC B, with a reduced endoplasmic reticulum and an almost quiescent Golgi complex, contain abundant lysosome structures and more seldom some neurosecretory granules. In fact, the study of the fine structure shows different intermediate types, linking in a continuous way typical A cells and typical B cells. NSC A and NSC B might correspond to two opposed stages of secretory activity of one single cell type: the A cell representing the activity stage and the B cell the quiescent stage.NSC C show an accumulation of their neurosecretory products in relation to metamorphosis and sexual maturity. Ultrastructural evidence confirms their neurosecretory activity.A mode of regulating neurosecretion in NSC A and B by internal catabolism of the secretion and formation of lysosome like structures is discussed in the present paper.The giant neurons, which are surrounded by a glial envelope (trophospongium), contain several dense granules originated from Golgi complex. 相似文献
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Hanne Gahéry-Ségard Evelyne Jouvin-Marche Adrien Six Carine Gris-Liebe Marie Malissen Bernard Malissen Pierre-André Cazenave Patrice N. Marche 《Immunogenetics》1996,44(4):298-305
The number of mouse Tcra-V gene segments varies from one individual to another and is estimated to be about 100. Southern blot analysis revealed that
most of the Tcra-V are organized in clusters composed of copies of Tcra-V belonging to different subfamilies. We analyzed in detail a Tcra-V subfamily and looked for new Tcra-V in order to improve the knowledge of the mouse Tcra locus organization. A series of genomic clones derived from the B10.A mouse strain enclosing these clusters was used to determined
the structure of all the Tcra-V2. We were able to identify ten Tcra-V2. This study showed that the Tcra-V2 can be organized into three structural subgroups. The distribution of the genes along the Tcra locus, plus their structural organization, indicates that successive duplications occurred during the processes of expansion
and contraction of the Tcra-V gene subfamilies. Several Tcra-V2 are also identical, indicating recent duplications. The most divergent Tcra-V2 differ by 7.4% nucleotides, leading to 5.2% differences in amino acid contents.
Received: 8 August 1995 / Revised: 24 April 1996 相似文献
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Josiane Girardie Adrien Girardie Alain Van Dorsselaer Odile Sorokine Serge Geoffre Michel Hospital Gilles Precigoux 《Journal of peptide science》1995,1(5):311-318
An original insect neurohormone of 65 residues was synthesized by the solid-phase methodology using t-Boc strategy and Boc-Val-PAM–resin. The purification, conducted by several steps of liquid chromatography having mass, polarity or charge as separative criteria, yielded the product with the correct molecular weight of 6922 Da determined by mass spectrometry. The synthetic peptide had both the same affinity for the antinative neurohormone serum and the same biological activity as the native neurohormone. 相似文献
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S Mellon-Nussbaum L Ponticorvo S Lieberman 《The Journal of biological chemistry》1979,254(24):12500-12505
Using mass spectrometric, radioisotopic, chromatographic and chemical techniques, five fatty acid esters of 3 beta-hydroxy-5-pregnen-20-one (pregnenolone) have been identified as components of the lipoidal derivatives biosynthesized in vitro with bovine adrenal mitochondria. The five compounds are: pregnenolone arachidonate, pregnenolone linoleate, pregnenolone oleate, pregnenolone palmitate, and pregnenolone stearate. The distribution of the fatty acids among these five esters is different from the previously reported (Cmelik, S.H.W., and Ley, H. (1977) Comp. Biochem. Physiol. 56B, 267-270) fatty acid composition of these organelles. 相似文献
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Clostridium paraputrificum, an obligate anaerobe recovered from human feces, reduces the alpha,beta-unsaturated carbonyl of deoxycorticosterone, corticosterone, cortisone, and cortisol. The same steroids are 21-dehydroxylated by Culture 116, recently isolated from human feces, and by a closely related organism, Eubacterium lentum. The 21-dehydroxylase has no effect on hydroxyl groups at carbon atoms 11 and 17. 相似文献
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Michel Roberge Gilles Grondin Louise Larose Adrien R. Beaudoin 《Cell and tissue research》1981,220(4):781-786
Summary Stimulation of the exocrine pancreas by the secretagogue urecholine causes degranulation of the acinar cells. Under in vivo conditions, this degranulation is not uniform throughout the tissue. Indeed some of the acini are almost completely depleted of their granules while others display the appearance of resting acini. A noticeable feature is that all the cells of the same acinus display a comparable degree of degranulation. Moreover, groups of neighbouring acini seem to respond simultaneously suggesting that the secretory stimulus is propagated from one acinus to the other. In vitro stimulation of dispersed acini also showed that some of the acini are more responsive than others indicating that this phenomenon can not be attributed to accessibility of the secretagogue to its receptor. These observations lead us to the concept that the response of the pancreatic acinar cell is controlled at the level of the acinus. 相似文献