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51.
The basic anatomy of lateral twig insertion onto the main branch in both healthy and damaged Quercus cerris L. trees was studied. An abscission zone is always present: in healthy trees it is formed by a smaller number of cell layers than in damaged ones, where it is more evident with many layers of cells. Cells of the abscission zone are roundish, with many intercellular spaces between them; cell walls are thin, non-lignified and without secondary walls. No starch was found in cells of the abscission zone, where, instead, a few scattered calcium oxalate druses are seen. 相似文献
52.
Alessandro Ferrari Felice Petraglia Erlio Gurpide 《The Journal of steroid biochemistry and molecular biology》1995,54(5-6):251-255
Decidualization of endometrial cells is a hormone-dependent process of differentiation which occurs during the menstrual cycle and pregnancy. Recent in vitro studies have revealed that cAMP and its generators induce decidualization of stromal cells isolated from proliferative endometrium and that progestins enhance the effect of cAMP. Since corticotropin releasing factor (CRF) generates cAMP and prostaglandins in other organs, in the present study the effect of CRF, a hypothalamic factor also produced by decidua and fetal membranes, on in vitro decidualization of endometrial stromal cells was evaluated. The addition of CRF to a culture medium of stromal cells induced in vitro decidualization, as indicated by morphologic changes from elongated fibroblast-like cells into larger and round cells and by the release of prolactin in the medium. The effect of CRF on stromal cells and on prolactin release was significantly augmented by the coincubation in the presence of medroxyprogesterone acetate. This observation indicates CRF as a novel factor of decidualization and confirms that progestins act as enhancers of the expression of decidual products. 相似文献
53.
Leilo Zolla Harry A. Kuiper Alessandro Finazzi Agrò Maurizio Brunori 《Journal of inorganic biochemistry》1984,22(3):143-153
Addition of KCN to Helix pomatia β-hemocyanin fully saturated with either O2 or CO results in a decrease of the spectroscopic properties of the protein (absorbance at 340 nm and luminescence at 550 nm) due to the displacement of the gaseous ligands (O2 or CO) from the active site. The anionic form of cyanide (CN?) is supposed to bind to the active site; its intrinsic affinity for the protein, as calculated from independent O2 and CO displacement experiments, is between 2 and 6 × 106M?1. The replacement of O2 or CO shows some differences which may be correlated with the different modes of binding at the active site. Thus, while displacement of oxygen by cyanide is hyperbolic, addition of cyanide to carbonylated hemocyanin shows a lag phase. This finding suggests the formation of a mixed liganded complex at the active site. The simultaneous presence of CO and CN? at the active site of hemocyanin is also supported by the experiment in which addition of small amounts of KCN to hemocyanin partially saturated with O2 and CO gives rise to an increase of emission intensity and a concomitant decrease of the O2 absorption band. The mixed-liganded species displays luminescence properties similar to those of CO-saturated hemocyanin, and the formation of the complex is reversible on dialysis or oxygenation. 相似文献
54.
Phytohemagglutinin, the major lectin in the seeds of the common bean Phaseolus vulgaris L., was isolated by affinity chromatography from cotyledons of nearly mature seeds and from developing cotyledons labeled with [3H]glucosamine, [3H]mannose or [3H]fucose. The protein was subjected to exhaustive proteolysis and the carbohydrate composition of the resulting glycopeptides examined. Two classes of oligosaccharide side-chains were found. The sidechains of the first class are of the high-mannose type, containing two residues of N-acetylglucosamine and 8 or 9 mannose residues. The sidechains of the second class are of the modified type containing N-acetylglucosamine, mannose, fucose, xylose in molar ratios of 2:3.8:0.6:0.5. Two-dimensional gel electrophoresis shows that phytohemagglutinin can be fractionated into seven different glycosylated polypeptides, and that each one contains at least one modified oligosaccharide chain. The results indicate that most glycosylated polypeptides probably contain one chain of each class. The carbohydrate composition of the two types of chains is similar to that found in other plant glycoproteins, but this is the first report of a plant glycoprotein with both highmannose and modified oligosaccharides on the same polypeptide chain.Abbreviations endo H
endo--N-acetylglucosaminidase H
- GlcN
glucosamine
- GlcNAc
N-acetylglucosamine
- Man
mannose
- PHA
phytohemagglutinin
This work was done while A.V. was on leave from the Istituto Biosintesi Vegetali, C.N.R., via Bassini 15, I-20133 Milano, Italy 相似文献
55.
Gino Toffano Silvio Mazzari Adriano Zanotti Alessandro Bruni 《Neurochemical research》1984,9(8):1065-1073
The influence of phosphatidylserine (PS) on the isoniazid-induced convulsions has been studied in mice. Sonicated dispersions of this phospholipid given intravenously do not show anticonvulsant activity but they do so when -aminobutyric acid (GABA) is simultaneously injected. GABA alone is inactive. The synergism between PS and GABA is influenced by the structure of the phospholipid liposomes. In contrast to multilamellar vesicles, oligolamellar vesicles are active. Under these conditions the effect shows head group specificity, in that the neutral phosphatidylcholine (PC) or the acidic phosphatidylinositol (PI) are inactive, either in the presence or in the absence of GABA. Lysophosphatidylserine (lysoPS), the deacylated PS derivative, shows increased efficacy as an isoniazid antagonist in the presence of GABA, and has anticonvulsant activity also in the absence of GABA. Other lysophospholipids are inactive. It is suggested that PS, after its metabolic conversion to lysoPS, enhances the anticonvulsant effect of GABA. 相似文献
56.
57.
Alessandro Ballio Renato Capasso Antonio Evidente Giuliano Grandolini Giacomino randazzo 《Phytochemistry》1982,21(7):1810-1811
The stereostructure of cotylenol, the aglycone of the cotylenins, has been confirmed by chemical correlation with the aglycone of fusicoccin A. 相似文献
58.
L Paradisi F Negro C Panagini M V Torrielli 《Bollettino della Società italiana di biologia sperimentale》1979,55(18):1877-1883
G-6-Pase activity was investigated in the microsomal fraction from rat liver in the presence of carbon tetrachloride and/or propyl gallate (PG), reduced glutathione (GSH) and superoxide dismutase. Results obtained "in vitro" demonstrated that CCl4 induced a 60% inhibition of the microsomal enzyme activity. Moreover, a marked inhibition of G-6-Pase activity was found also when propyl gallate and reduced glutathione were added, at different concentrations, to incubation mixture. In addition, these drugs were unable to interfere with the dangerous effect exerted on the enzymatic activity by the haloalkane. Additional experiments carried out "in vivo" with propyl gallate produced evidence that intraperitoneal administration of the antioxidant was followed by a significant inhibition of G-6-Pase activity, while the damaging action of CCl4 was unaffected. Some possible explanations of these results are reported. 相似文献
59.
Romano Tenconi Emanuela Piovan Alessandro Preto Roberto Magnabosco Carlo Baccichetti 《Human genetics》1977,39(1):97-101
Summary Familial 12/15 translocation with a child trisomic for the short arm of chromosome 12 (segment p 12.1pter) is reported. The clinical picture of the child is strikingly similar to previous reports of 12p trisomy. The main symptoms of 12p syndrome are defined. 相似文献
60.
Cloning and expression of human ciliary neurotrophic factor 总被引:1,自引:0,他引:1
A Negro E Tolosano S D Skaper I Martini L Callegaro L Silengo F Fiorini F Altruda 《European journal of biochemistry》1991,201(1):289-294
Ciliary neurotrophic factor (CNTF) is a survival factor for avian ciliary ganglion neurons and a variety of other neuronal cell types in vitro. We report here the cloning of the entire genomic sequence encoding human CNTF and its primary structure. Biologically active CNTF has been expressed in Chinese hamster ovary cells from a human genomic DNA clone. Human CNTF has no significant sequence similarity to any previously reported protein, although approximately 84% similarity exists compared with rat and rabbit CNTF. The lack of both an N-terminal signal sequence and consensus sequences for glycosylation or hydrophobic regions, and the fact that active CNTF is expressed but not released into the culture medium of transfected cells, argue in favour of human CNTF as a cytosolic protein. These data provide a basis for understanding the role of CNTF in nervous system physiology and pathology. 相似文献