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121.
Summary The occurrence of plasmodesmata in the graft interfaces of two heteroplastic grafts (Impatiens walleriana onImpatiens olivieri andHelianthus annum onVicia faba) has been studied. For both systems two types of intercellular strand are described: 1. Continuous plasmodesmata interconnecting the cells of stock and scion and 2. half plasmodesmata traversing the wall part of one partner cell without connection to the abutting cell. Single strands or branched forms occur in both types of plasmodesma. In the case of half plasmodesmata, branchings with extended median nodules predominate. The distribution of half and continuous plasmodesmata varies with the different areas of a graft interface: in the region of bridging vascular tissues most cell connections are continuous. In areas where cortex or pith-derived callus cells and those of misaligned tissues (cortex/vascular tissue; cortex/pith; pith/vascular tissue) match, discontinuous strands predominate.Branched half plasmodesmata also occur in presumably fused walls between related callus cells; they are typical structures secondarily formed in non-division walls.The results are discussed with regard to compatibility/incompatibility phenomena in heterografts and the development and function of interspecific cell bridges. 相似文献
122.
Lott Timothy J.; Yang Junghui; Ye Jianhong; Wallace Douglas C. 《Bioinformatics (Oxford, England)》1985,1(4):249-252
We have developed an inexpensive yet versatile microcomputer-basedsystem for quantitating light intensity levels in autoradiographs.This system employs a standard video camera interfaced to ananalog-to-digital convertor. A program has been written forthis system which can measure intensities within a defined regionof an autoradiograph, permitting an easy and accurate quantitationof spots or bands of irregular shape.
Received on June 18, 1985; accepted on September 3, 1985 相似文献
123.
<正> 我们实验室曾报道,用胆酸盐透析法将猪心线粒体H~+-ATP酶嵌入大豆磷脂脂质体形成脂酶体时,透析液中Mg~(2+)的存在会降低脂酶体的膜脂流动性,并明显提高重建H~+-ATP酶的活性以及对寡霉素或DCCD的敏感性,因而推论Mg~(2+)的作用很可能是通过改变膜脂的物理状态,形成了维持H~+-ATP酶较高活性的合适构象。但共确切的作用机制仍 相似文献
124.
On the mechanism of activation of the ATP X Mg(II)-dependent phosphoprotein phosphatase by kinase FA 总被引:4,自引:0,他引:4
S Jurgensen E Shacter C Y Huang P B Chock S D Yang J R Vandenheede W Merlevede 《The Journal of biological chemistry》1984,259(9):5864-5870
The mechanism of activation of the Mg(II) X ATP-dependent phosphatase by the kinase FA has been investigated. The inactive protein phosphatase can be represented as FC X M where FC is the inactive catalytic component and M is the heat-stable modulator protein (also known as inhibitor-2). Phosphorylation of the modulator protein is demonstrated during activation of FC X M. In addition, continuous ATP hydrolysis during the activation is observed. This suggests that a cyclic phosphorylation-dephosphorylation reaction is continuously occurring during the activation. It is proposed that phosphorylation of the modulator protein causes an isomerization in FC to generate an active phosphatase. The activated phosphatase is capable of dephosphorylating the phosphorylated modulator. Upon dephosphorylation of modulator, the active phosphatase returns to its inactive form via a slow isomerization. 相似文献
125.
This investigation examines the immunologic basis for specific antigen-induced tube leukocyte adherence inhibition (LAI) reactivity of draining lymph node cells (LNC) from dogs with canine transmissible venereal sarcoma (CTVS). CTVS regressor LNC, macrophage-depleted LNC, and enriched T lymphocyte fractions, but not enriched B lymphocyte fractions, were specifically reactive to CTVS antigen extract in direct tube LAI. In addition, regressor LNC amplified tube LAI responses by generating supernatants with leukocyte adherence inhibition factor (LAIF) activity for normal dog indicator LNC and enriched peripheral blood mononuclear cells (PBMC) in an indirect tube LAI assay. However, macrophage-depleted LNC and enriched T lymphocyte fractions failed to generate supernatants with LAIF activity, suggesting that macrophage accessory cells play a central role in the amplification of tube LAI. Interestingly, CTVS regressor peripheral blood leukocytes (PBL) and PBMC, which were specifically reactive in direct tube LAI, also failed to generate supernatants with LAIF activity. These findings demonstrate a distinction between LAIF-mediated amplification and direct tube LAI reactivity, and suggest that leukocyte populations with differing cellular proportions and from different immunologic compartments may participate in tube LAI via different mechanisms. 相似文献
126.
127.
128.
In vitro growth and differentiation of human kidney tubular cells on a basement membrane substrate 总被引:4,自引:0,他引:4
An Hang Yang Jeanine Gould-Kostka Terry D. Oberley 《In vitro cellular & developmental biology. Plant》1987,23(1):34-46
Summary Kidney cortical tubular cells, mainly proximal tubular cells, isolated from human kidney and grown either on a basement membrane
substrate in chemically defined medium or on plastic in serum-supplemented medium, had substantial proliferative potential
and could be propagated for more than 10 generations or 8 passages before senescence. Basement membrane produced on a plastic
substrate by the HR-9 endodermal cell line could replace serum supplementation in promoting tubular cell growth. Tubular cells
grown on an HR-9 basement membrane substrate exhibited stable epithelial morphology over an extended period of time; in the
presence of 5% serum they differentiated into organized structures such as hemicysts and cell cords. Cells grown on plastic
failed to differentiate and gradually degenerated. Tubular cells on HR-9 basement membrane were characterized by densely packed
microvilli, abundant rough endoplasmic reticulum and free polysomes, basal cell membrane interdigitations, a well-developed
endocytotic apparatus, and conspicuous junctional complexes—all features of the proximal tubular cell. Compared with cells
on plastic substrate, there were higher levels of the brush border enzymes γ-glutamyl transpeptidase,l-leucine aminopeptidase, and alkaline phosphatase in cells maintained on an HR-9 basement membrane substrate, further supporting
the conclusion that a basement membrane substrate promoted differentiation of tubular cells. These data and morphological
observations indicate that a basement membrane substrate can promote growth and both functional and morphologic differentiation
of human kidney tubular cells.
This work was supported by the Veterans Administration. 相似文献
129.
Kidney glomerular explants in serum-free media. Sequential morphologic and quantitative analysis of cell outgrowths 总被引:3,自引:0,他引:3
T D Oberley B W Steinert A H Yang P J Anderson 《Virchows Archiv. B, Cell pathology including molecular pathology》1986,50(3):209-235
Guinea pig glomeruli were grown in vitro for 22 days in a serum-free medium composed of Waymouth's MB 752/1 supplemented with sodium pyruvate, nonessential amino acids, antibiotics, insulin, transferrin, selenium, triiodothyronine, and fibronectin (FN), and sequential morphologic and quantitative studies of cell outgrowth were performed. Glomeruli grown in serum-free medium showed preservation of glomerular visceral epithelial cells but extensive necrosis of endocapillary cells (endothelial and mesangial cells). Morphologic analysis demonstrated progressive morphologic changes in cultured glomerular cells; however, most cell types observed in culture appeared to grow from the epithelial side of the glomerular basement membrane. Mitosis was a prominent component of glomerular cell outgrowth in vitro, and total DNA increased slightly during glomerular culture. FN was required for glomerular cell outgrowth, and studies using FN fragments demonstrated that the carboxy-terminal portion of FN was required for whole glomerular attachment. These results are used to develop a model for glomerular cell outgrowth in vitro. 相似文献
130.
Kaiyu Yang 《World journal of microbiology & biotechnology》1986,2(4):421-426
Summary Studies on immobilized enzymes and whole cells have been made since 1970 in China. A new method for immobilization was developed by using the bifunctional reagent, -sulphatoethyl-sulphonylaniline to activate polysaccharides. More than ten immobilized biocatalysts such as polynucleotide phosphorylase and penicillin acylase, have been used in the pharmaceutical industry, the production of high value chemicals, and in pollutant treatment. The prospects and scientific constraints in this field are discussed in this paper.
Paper presented at the VII International Conference on the Global Impacts of Applied Microbiology, Helsinki, 12–16 August 1985. 相似文献
Resumen Desde 1970 se estan llevando a cabo en China estudios sobre enzimas inmovilizados y células enteras. Un nuevo método para la inmovilización fue diseñado utilizando el reactivo bifuncional -sulfatoetilsulfonilanilina para activar polisacaridos. Màs de 10 biocatalizadores inmovilizados, tales como polinucleotidofosforilasa y penicillin-acilasa, se han utilizado en la industria farmaceútica, en la producción de compuetos químicos de alto coste y en el tratamiento de polucionantes. En este trabajo se discuten las perspectivas y las dificultades científicas en este campo.
Résumé Des études sur les enzymes fixés et les cellules immobilisées ont été entreprises en Chine à partir de 1970. II a été mis au point une nouvelle méthode d'immobilisation, utilisant pour l'activation des polysaccharides un réactif bifonctionnel, la -sulphato-éthyl-sulphonyl-aniline. Plus de 10 biocatalyseurs immobilisés, dont la polynucléotide-phosphorylase et la pénicilline-acylase, ont été employés dans l'industrie pharmaceutique, pour la production de composés chimiques à haute valeur commerciale et pour la dépollution. Les perspectives et les contraintes scientifiques dans le domaine considéré sont discutées.
Paper presented at the VII International Conference on the Global Impacts of Applied Microbiology, Helsinki, 12–16 August 1985. 相似文献