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11.
Katayoon Dehesh Aubrey Jones Deborah S. Knutzon Toni A. Voelker 《The Plant journal : for cell and molecular biology》1996,9(2):167-172
The Mexican shrub Cuphea hookeriana accumulates up to 75% caprylate (8:0) and caprate (10:0) in its seed oil. An acyl-ACP thioesterase cDNA from C. hookeriana , designated Ch FatB2 , has been identified, which, when expressed in Escherichia coli , provides thioesterase activity specific for 8:0- and 10:0-ACP substrates. Expression of this clone in seeds of transgenic canola, an oilseed crop that normally does not accumulate any 8:0 and 10:0, resulted in a dramatic increase in the levels of these two fatty acids accompanied by a preferential decrease in the levels of linoleate (18:2) and linolenate (18:3). The Ch FatB2 differs from Ch FatB1 , another Cuphea hookeriana thioesterase reported recently, in both substrate specificity and expression pattern. The Ch FatB1 has a broad substrate specificity with strong preference for 16:0-ACP and is expressed throughout the plant; whereas Ch FatB2 is specific for 8:0/10:0-ACP and its expression is confined to the seed. It is proposed that the amplified expression of Ch FatB2 in the embryo provides the hydrolytic enzyme specificity determining the fatty acyl composition of Cuphea hookeriana seed oil. 相似文献
12.
The proteolytic degradation in vitro of the NADPH-protochlorophyllide oxidoreductase of barley (Hordeum vulgare L.) 总被引:9,自引:0,他引:9
Isolde Häuser Katayoon Dehesh Klaus Apel 《Archives of biochemistry and biophysics》1984,228(2):577-586
A cell-free membrane system has been developed from isolated barley etioplasts which displays a highly selective decrease of the NADPH-protochlorophyllide oxidoreductase in vitro which is indistinguishable from that observed previously in the intact plant. The rapid breakdown of the enzyme protein in vitro is caused by a membrane-bound proteolytic activity. The protease is essentially independent of pH in the physiological pH range of 6 to 8.5. The optimum temperature for the reaction is approximately 40 degrees C. In the presence of excessive protochlorophyllide the enzyme is no longer degraded or inactivated during illumination of dark-grown plants. In the isolated membrane fraction protochlorophyllide also enhances the stability of the enzyme, a similar effect is exerted by NADPH but not by NADH. The results suggest that the inactivation of the NADPH-protochlorophyllide oxidoreductase is influenced by the interaction of the enzyme with protochlorophyllide and NADPH. In the absence of these two components the enzyme becomes susceptible to proteolytic degradation. 相似文献
13.
Recently, some evidence for the occurence of a light-independent protochlorophyllide-reducing enzyme in greening barley plants has been presented. In the present work this problem was reinvestigated. -[14C] Aminolevulinic acid was fed to isolated barley shoots from plants which had been preilluminated for various lengths of time. Porphyrins which had been synthesized during the dark incubation were analyzed by high-performance liquid chromatography. There was no evidence for a light-independent synthesis of chlorophyll(ide). The 14C-labelled precursor was incorporated almost exclusively into protochlorophyllide. The reduction of labelled protochlorophyllide to chlorophyllide was strictly light-dependent. These results are not consistent with the existence of a light-independent protochlorophyllide-reductase in barley as proposed previously.Abbreviation HPLC
high-performance liquid chromatography 相似文献
14.
The localization of NADPH-protochlorophyllide oxidoreductase (PChlide reductase, EC 1.6.99.–) in dark-grown and in irradiated dark-grown leaves of wheat ( Triticum aestivum L. cv. Walde) was investigated by subjecting thin sections of Lowicryl K4M-embedded leaf pieces to a monospecific antiserum raised against PChlide reductase followed by protein A-gold. A well-preserved antigenicity of the tissue was achieved by polymerizing the resin under UV-light at low temperature. In dark-grown leaves PChlide reductase was found in prolamellar bodies only. In leaves irradiated for 30 min with white light PChlide reductase was found not only in the transformed prolamellar bodies but also to a large extent in connection with the prothylakoids. The localization of PChlide reductase is discussed in relation to fluorescence emission spectra of the dark-grown and greening leaves. We conclude that the light-dependent transformation of protochlorophyllide to chlorophyllide initiates a translocation of PChlide reductase from the prolamellar bodies to the prothylakoids. 相似文献
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16.
Steven JM Jones Janessa Laskin Yvonne Y Li Obi L Griffith Jianghong An Mikhail Bilenky Yaron S Butterfield Eric Chuah Richard Corbett Anthony Fejes Simon Chan Nancy Liao Katayoon Kasaian Malachi Griffith John Yee Montgomery Martin Michael Mayo Nataliya Melnyk Ryan D Morin Trevor J Pugh Tesa Severson Sohrab P Shah Margaret Sutcliffe Angela Tam Jefferson Terry Nina Thiessen Thomas Thomson Richard Varhol Thomas Zeng Yongjun Zhao Richard A Moore David G Huntsman Inanc Birol Martin Hirst Robert A Holt Marco A Marra 《Genome biology》2010,11(Z1):I5
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18.
Katayoon Pakravan Ehsan Razmara Bashdar Mahmud Hussen Fatemeh Sattarikia Majid Sadeghizadeh Sadegh Babashah 《Journal of cellular and molecular medicine》2022,26(1):1
Different cellular and molecular mechanisms contribute to chondrocyte and osteocyte development. Although vital roles of the mothers against decapentaplegic homolog 4 (also called ‘SMAD4’) have been discussed in different cancers and stem cell‐related studies, there are a few reviews summarizing the roles of this protein in the skeletal development and bone homeostasis. In order to fill this gap, we discuss the critical roles of SMAD4 in the skeletal development. To this end, we review the different signalling pathways and also how SMAD4 defines stem cell features. We also elaborate how the epigenetic factors—ie DNA methylation, histone modifications and noncoding RNAs—make a contribution to the chondrocyte and osteocyte development. To better grasp the important roles of SMAD4 in the cartilage and bone development, we also review the genotype‐phenotype correlation in animal models. This review helps us to understand the importance of the SMAD4 in the chondrocyte and bone development and the potential applications for therapeutic goals. 相似文献
19.
The composition and positional distribution of lipids in developing and mature transgenic Brassica napus seeds accumulating up to 7 mol% of caprylate (8:0), 29 mol% caprate (10:0) or 63 mol% of laurate (12:0) were examined. The
accumulation of 8:0 and 10:0 resulted from over-expression of the medium-chain-specific thioesterase (Ch FatB2) alone or together with the respective chain-length-specific condensing enzyme (Ch KASIV). Seeds containing high levels of 12:0 were obtained from plants expressing bay thioesterase (BTE) alone or crossed
with a line over-expressing the coconut lysophosphatidic acid acyltransferase (LPAAT), an enzyme responsible for the increase
in acylation of 12:0 at the sn-2 position. In all instances, 10:0 and 12:0 fatty acids were present in substantial amounts in phosphatidylcholine during
seed development with a drastic decrease of 80–90% in mature seeds. At all stages of seed development however, 8:0 was barely
detectable in this membrane lipid. Altogether, these results indicate that these transgenic seeds exclude and/or remove the
medium-chain fatty acids from their membrane and that this mechanism(s) is more effective with the shorter-chain fatty acids.
Furthermore, seeds of 8:0- and 10:0-producing lines had only negligible levels of these fatty acids present in the sn-2 position of the triacylglycerols. In contrast, all 12:0-producing seeds had a substantial amount of this fatty acid in
the sn-2 position of the triacylglycerols, suggesting that the endogenous LPAAT is able to acylate 12:0 if no other acyl-CoA species
are available.
Received: 11 February 2000 / Accepted: 2 May 2000 相似文献
20.
Katayoon KHERADMAND Karim KAMALI Yaghoub FATHIPOUR Edward UECKERMANN Ebrahim Mohammadi GOLTAPEH 《昆虫学报》2007,50(4):416-422
2004年春季至2006年夏季期间,调查了伊朗Karaj地区双孢蘑菇上的螨类,发现了3目9科17种食菌性、捕食性和腐食性螨类,包括:光滑巨螯螨Macrocheles glaber (Müller),粪巨螯螨Macrocheles merdarius (Berlese),近褐巨螯螨Macrocheles subbadius(Berlese),甲虫寄螨Parasitus coleoptratorum (Linnaeus),粪堆寄螨Parasitus fimetorum (Berlese),乳突寄螨Parasitus mammillatus (Berlese),Sancassania rodionovi Zachvatkin,腐食酪螨Tyrophagus putrescentiae (Schrank),Uroobovella fimicola (Berlese),Ameroseius fungicolus* Masan,Pediculaster kneeboni* Wicht,Pediculaster flechtmanni* Wicht,Scutacarus longitarsus (Berlese),Dendrolaelaps multidentatus* Masan,柴特北绥螨Arctoseius cetratus (Sellnick),Lasioseius sugawarai* Ehara和Ameroseius plumigera Oudemans。其中有“*”号标记的6个种为伊朗新纪录种,12个种为在蘑菇上首次发现。 相似文献