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51.
cDNA cloning of an extracellular dermal glycoprotein of carrot and its expression in response to wounding 总被引:2,自引:0,他引:2
Suspension-cultured cells of carrot (Daucus carota L.) synthesize and secrete a glycoprotein that is normally found only in dermal tissues (epidermis, endodermis and periderm). This protein, previously called GP57, is now referred to as EDGP (E xtracellular D ermal G lyco P rotein). We purified sufficient quantities of EDGP to obtain amino-acid sequences on two internal tryptic peptides and screened a cDNA library of young carrot roots with antiserum to EDGP and with oligonucleotides corresponding to the peptides. Here we report the derived amino-acid sequence of EDGP. Sequence comparisons show that it has 40% amino-acid sequence identity with 7S basic globulin, a protein that is released when soybean seeds are soaked in hot water for a few hours. We suggest that these two proteins belong to a new family of dermal proteins. As far as we know, this is the first reported derived amino-acid sequence for protein that is specific to the epidermis and other dermal tissues. The level of EDGP mRNA is low in dry seeds, but increases rapidly in growing seedlings as they develop dermal tissues. The level of mRNA is low in storage roots, but increases rapidly in response to wounding. The presence of EDGP in dermal tissues and its up-regulation in response to wounding indicate a role in the response of plants to biotic and-or abiotic stresses. An unusual feature of the amino-acid sequence of EDGP is that it contains a short motif, which is present at the active site of aspartyl proteases such as pepsin and chymosin.Abbreviations cDNA
copy DNA
- 2,4-D
2,4-dichlorophen-oxyacetic acid
- EDGP
extracellular dermal glycoprotein
- 7SBG
7S basic globulin
Supported by a contract from the United States Department of Energy (Energy Biosciences) (to M.J.C.) and a Grant-in-Aid for Special Research on Priority Areas (01660002, Cellular and Molecular Basis for Reproductive Processes in Plants) from the Ministry of Education, Science and Culture, and by the Fund from Basic Research Core System of Science and Technology Agency, Japan (to S.S.). 相似文献
52.
Proteins and Carbohydrates in Xylem Sap from Squash Root 总被引:8,自引:0,他引:8
Satoh Shinobu; Iizuka Chika; Kikuchi Akira; Nakamura Norio; Fujii Tadashi 《Plant & cell physiology》1992,33(7):841-847
The xylem sap from squash roots was collected from the cut surfaceof stems, and the proteins and carbohydrates in the sap wereanalyzed. The sap contained 18.6 µg ml1 proteinand the major polypeptides were as follows: 1) two polypeptides,of 75 and 40 kDa, with high-mannose glycans, the levels of whichincreased for about 24 h after cutting and then decreased; 2)a 32-kDa polypeptide, which appeared soon after cutting, disappearedand then reappeared again 4864 h after cutting; and 3)a 19-kDa and a 14-kDa polypeptide, which were present constitutively.The carbohydrates contained in the xylem sap were fractionatedinto 80% ethanol-soluble and -insoluble material, and whichwere analyzed by high-performance liquid chromatography, gaschromatography and enzymatic mathods. The former fraction containedconsiderable amounts of myo-inositol and fructose as free sugarsand oligosaccharides composed mainly of galactose, arabinoseand glucose. The latter contained polysaccharides composed mainlyof uronic acids, galactose and arabinose. The possible significanceof these substances, which may mediate the interactions betweenthe root and the aerial organs, is discussed. (Received April 20, 1992; Accepted July 4, 1992) 相似文献
53.
Masayuki Taniguchi Mitsuo Tanaka Ryuichi Matsuno Tadashi Kamikubo 《Applied microbiology and biotechnology》1982,14(1):35-39
Summary Rice straw was treated with NaOH, peracetic acid (PA), and sodium chlorite (NaClO2). Quantitative changes in the composition of the treated straw, crystallinity of the treated straw and extracted cellulose, and susceptibility of the treated straw to Trichoderma reesei cellulase were studied. The alkali treatment resulted in a remarkable decrease in hemicellulose as well as lignin. Consequently, the recovery of residual straw after NaOH treatment was lowest among the three chemical reagents evaluated. The treatment with PA or NaCIO2 resulted in a slight loss in hemicellulose and cellulose in the straw. The three chemical treatments caused little or no breakdown of the crystalline structure of cellulose in the straw. The treated straw was solubilized with the culture filtrate of T. reesei. The degree of enzymatic solubilization relative to the amount of residual straw was 69% after treatment with 0.25 N NaOH, 42% after treatment with 20% PA, and 50% after treatments with NaClO2 (twice). The degree of enzymatic solubilization relative to the amount of the untreated straw, however, was 30% after treatment with 0.25 N NaOH, 32% after treatment with 20% PA, and 37% after treatments with NaClO2 (twice). 相似文献
54.
Koichi Hirata Tadashi Oku Aaron E. Freeman 《In vitro cellular & developmental biology. Plant》1982,18(9):789-799
Summary Twenty to twenty-two days postcoitum mouse fetal pancreas organ bits were cultured on the dermal surface of irradiated pigskin
as a substrate. The medium used for long term culture consisted of Eagle’s Minimum Essential Medium with the addition of 10%
bovine serum, 0.02 U/ml insulin, 0.025 μg/ml glucagon, 3.63 μg/ml hydrocortisone, 100 μg/ml soybean trypsin inhibitor or 10−8
M atropine. When the medium lacked trypsin inhibitor or atropine but contained the three hormones, the pigskin support began
to be destroyed after 2 to 4 wk in culture. Thereafter, the cultured cells could not grow and survive on the digested pigskin.
When 10−6
M atropine was added to the medium, amylase secretion from cultured cells and destruction of pigskin were inhibited completely
but pancreas cells could not grow or survive. In contrast, 100 μg/ml soybean trypsin inhibitor or 10−8
M atropine permitted cell growth, permitted amylase secretion from the cultured acinar cells, and prevented the destruction
of pigskin. Under these conditions pancreas cells migrated or grew or both from the organ bits onto the surface of the pigskin
dermis and organoid aggregations formed. Hydrocortisone was needed to permit growth for more than 2 wk. Glucagon and insulin
had additive effects. Light and electron microscopic observations indicated the culture of at least five kinds of cells, i.e.,
duct, acinar, centroacinar, endocrine, and mesenchymal. The majority of cultured cells were duct cells and acinar cells. There
were few mesenchymal cells. Mouse pancreas cells were cultured for at least 12 wk by this method.
This investigation was supported by PHS Grant CA 30220 awarded by the National Cancer Institute, DHHS, Grant 1203M awarded
by the Council for Tobacco Research, Inc., and Grant RD-65 (for equipment) awarded by the American Cancer Society. Nude mice
were provided by Dr. Wendall M. Farrow of Life Sciences, Inc., Resource Laboratory N01, CP6-1005 of the National Cancer Institute. 相似文献
55.
Independently derived mutants of Chinese hamster ovary cells have been isolated and shown to exhibit a subtle glycosylation defect resulting in the premature termination of certain asparagine-linked carbohydrate moieties. This carbohydrate alteration is akin to the types of structural variation termed microheterogeneity and is thought not to affect the biological activities of glycoproteins that manifest the phenomenon. However, the carbohydrate change expressed by the mutants is stable and heritable, and 1251-lectin-binding studies suggest that it profoundly alters their surface recognition properties. The mutation appears to affect a specific subpopulation of galactose residues in asparagine-linked carbohydrate of the type found associated with the G glycoprotein of vesicular stomatitis virus. The mutant cells also exhibit morphological changes in substratum culture. 相似文献
56.
Small circular DNA complexes in eucaryotic cells 总被引:7,自引:0,他引:7
A small number of eucaryotic cells (100 to 1000 cells) were pressed by mica sheet; then the extruded contents were adsorbed on mica and processed for electron microscopy. In the absence of divalent cation, small polydisperse circular DNA molecules bound to proteins or membrane material were preferentially adsorbed. The small circular DNA complexes have been found in every eucaryotic cell, primary lymphoid tissue cells of bursa and thymus, primary cell lines of retina and liver, and established cultured cell lines of embryonal teratocarcinoma, F9 and PCC3, HeLa and 3T6. Size distribution of these DNA complexes varies, depending on the cell source. The circles less than 1 μm in contour length predominate in cultured cell lines and the larger ones in primary cell lines and cells in situ. Polydisperse covalently closed circular DNAs were recovered from thymus lymphocytes by the conventional dye-CsCl buoyant density method. Their size distribution was similar to that of the small circular DNA complexes detected by the mica-press-adsorption method. They are present in several tens to hundreds of copies per cell representing, at a maximum, 0.02% of the total cellular DNA. The possibility that small circular DNA complexes may result from gene rearrangement as well as from replicon “misfiring” (A. Varshavsky, 1981, Proc. Nat. Acad. Sci. USA 78, 3673–3677) are discussed. 相似文献
57.
Takeshi Kato Kimi Iwase Toshiharu Nagatsu Masami Hino Tadashi Takemoto Shumpei Sakakibara 《Molecular and cellular biochemistry》1979,24(1):9-13
Summary A new assay procedure for X-prolyl dipeptidyl-aminopeptidase activity in human serum was developed with glycylproline p-phenylazoanilide tosylate as substrate. p-Phenylazoaniline liberated by the enzyme reaction was measured photometrically at 493 nm after stopping the reaction with acid. This assay was simple and sensitive, and less than 50 l of human serum was required for the assay. Km value was 2.5 mm and the optimum pH was 8.7. After disc gel electrophoresis of human serum, the enzyme activity could be distinctly observed as a reddish band on the gel when the gel was incubated with this substrate. 相似文献
58.
Hiroshi Sagami Kyozo Ogura Shuichi Seto Tadashi Kurokawa 《Biochemical and biophysical research communications》1978,85(2):572-578
A new prenyltransferase which catalyzes the synthesis of geranyl pyrophosphate as the only product from dimethylallyl pyrophosphate and isopentenyl pyrophosphate has been separated from other known prenyltransferases from . This enzyme fraction is also capable of synthesizing all- geranylgeranyl pyrophosphate from farnesyl pyrophosphate and isopentenyl pyrophosphate though it lacks ability to synthesize farnesyl pyrophosphate. 相似文献
59.
Five triterpenoid saponins isolated from the flowers, the mature fruits and the leaves of Fatsia japonica were identified as 3-O-[β-d-glucopyranosyl(1→4)-β-d-glucopyranosyl]-hederagenin (1), 3-O-[β-d-glucopyranosyl-(1→4)-α-l-arabinopyranosyl]-oleanolic acid (2), 3-O-[α-l-arabinopyranosyl]-hederagenin (3), 3-O-[β-d-glucopyranosyl]-hederagenin (4) and 3-O-[β-d-glucopyranosyl(1→4)-α-l-arabinopyranosyl]-hederagenin (5). The saponins 1 and 2 are new, naturally occurring, triterpenoid saponins. The distribution of the five saponins in three parts of the plant was investigated. Saponins 2, 3 and 5 were present in the flowers, saponins 1, 3, 4 and 5 were in the mature fruits and saponins 2, 3, 4 and 5 were in the leaves. 相似文献
60.
Exposure of Avena coleoptile sections to 8% O2 brought aboutrespiration decrease, resulting in a decrease of ATP production.The pH at the cell wall surface slightly rose in sections exposedto 8% O2, while their growth was greatly accelerated. Moreover,this growth acceleration was observed even in sections treatedwith CCCP known to make membranes permeable for protons. Weconcluded that the growth acceleration with reduction of O2concentration is probably not the result of secretion of H+ions into cell wall compartments. Results of this study provided evidence to support the hypothesisthat there is an inverse relationship between hydroxyproline-proteinlevel and the ability of a cell to undergo rapid cell elongation.Total labeling of the cell wall fraction with 14C-proline wasunaffected by 8% O2 treatment, although the radioactivitiesof hydroxyproline incorporated into this fraction during thetreatments fell to about 45% of the control. Moreover, the radioactivitiesof hydroxyproline incorporated into the SLS-insoluble cell wallfraction of sections exposed to 8% O2 decreased to about 30%of the control. This decrease of hydroxyproline was also observedin sections treated with cycloheximide, which inhibits the secretionof H+ ions into the cell wall compartment. Reduction of O2 concentrationin the surrounding atmosphere affects not only the hydroxylationof peptidyl proline, but also the binding of hydroxyproline-protein(s)to cell wall polysaccharides, and the resulting decrease ofthe protein rigidly bound to them may induce cell elongation. (Received December 5, 1975; ) 相似文献