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241.
Expression of deacetylvindoline-4-O-acetyltransferase in Catharanthus roseus hairy roots 总被引:3,自引:0,他引:3
Madagascar periwinkle [Catharanthus roseus (L.) G Don] is a pantropical plant of horticultural value that produces the powerful anticancer drugs vinblastine and vincristine that are derived from the dimerization of the monoterpenoid indole alkaloids (MIAs), vindoline and catharanthine. The present study describes the genetic engineering and expression of the terminal step of vindoline biosynthesis, deacetylvindoline-4-O-acetyltransferase (DAT) in Catharanthus roseus hairy root cultures. Biochemical analyses showed that several hairy root lines expressed high levels of DAT enzyme activity compared to control hairy root cultures expressing β-gulucuronidase activity (GUS) activity. Metabolite analysis using high performance liquid chromotagraphy established that hairy root extracts had an altered alkaloid profile with respect to hörhammericine accumulation in DAT expressing lines in comparison to control lines. Further analyses of one hairy root culture expressing high DAT activity suggested that DAT expression and accumulation of hörhammericine (9) were related. It is concluded that expression of DAT in hairy roots altered their MIA profile and suggests that further expression of vindoline pathway genes could lead to significant changes in alkaloid profiles. Evidence is provided that hörhammericine (9) accumulates via a DAT interaction with the root specific minovincinine-19-O-acetyltransferase (MAT) that inhibits the MAT mediated conversion of hörhammericine (9) into 19-O-acetyl-hörhammericine (12). 相似文献
242.
Exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine by increasing antioxidant enzyme activities 总被引:3,自引:0,他引:3
Hoque MA Okuma E Banu MN Nakamura Y Shimoishi Y Murata Y 《Journal of plant physiology》2007,164(5):553-561
Proline and betaine accumulate in plant cells under environmental stresses including salt stress. Here, we investigated effects of proline and betaine on the growth and activities of antioxidant enzymes in tobacco Bright Yellow-2 (BY-2) culture cells in suspension under salt stress. Both proline and betaine mitigated the inhibition of growth of BY-2 cells under salt stress and the mitigating effect of proline was more than that of betaine. Salt stress significantly decreased the activities of superoxide dismutase (SOD), catalase and peroxidase in BY-2 cells. Exogenous application of proline or betaine alleviated the reduction in catalase and peroxidase activities but not SOD activity under salt stress. In addition, proline was found to be effective in alleviating the inhibition of salt stress-induced catalase and peroxidase activities in BY-2 cells. Neither proline nor betaine directly scavenged superoxide (O(2)(-)) or hydrogen peroxide (H(2)O(2)). It is concluded that exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine because of its superior ability to increase the activities of antioxidant enzymes. 相似文献
243.
Hoque MA Banu MN Okuma E Amako K Nakamura Y Shimoishi Y Murata Y 《Journal of plant physiology》2007,164(11):1457-1468
Up-regulation of the antioxidant system provides protection against NaCl-induced oxidative damage in plants. Antioxidants and activity of enzymes involved in the ascorbate-glutathione (ASC-GSH) cycle in tobacco Bright Yellow-2 (BY-2) were investigated to assess the antioxidant protection offered by exogenous proline and glycinebetaine (betaine from now on) against salt stress using cells grown in suspension culture. Reduced ascorbate (ASC) was detected in BY-2 cells but dehydroascorbate (DHA) was not. Large quantities of a reduced form of glutathione (GSH) and smaller quantities of an oxidized form of glutathione (GSSG) were detected in BY-2 cells. Salt stress significantly reduced the contents of ASC and GSH as well as activities of ASC-GSH cycle enzymes such as ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR). Exogenous proline or betaine increased the activities of all enzymes except MDHAR involved in NaCl-induced ASC-GSH cycle. Levels of ASC and GSH in BY-2 cells under salt stress were lower in the presence of proline or betaine than in the absence of proline or betaine whereas there was no difference in redox status. Proline proved more effective than betaine in maintaining the activity of enzymes involved in NaCl-induced ASC-GSH cycle. Neither proline nor betaine had any direct protective effect on NaCl-induced enzyme activity involved in the antioxidant system; however, both improved salt tolerance by increasing enzyme activity. The present study, together with our earlier findings [Hoque MA, Okuma E, Banu MNA, Nakamura Y, Shimoishi Y, Murata Y. Exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine by increasing antioxidant enzyme activities. J Plant Physiol 2006;164:553-61.], suggests that proline offered greater protection against salt stress than betaine did because proline was more effective in increasing the activity of enzymes involved in the antioxidant system. 相似文献
244.
Koizumi J Kojima T Kamekura R Kurose M Harimaya A Murata M Osanai M Chiba H Himi T Sawada N 《The Journal of membrane biology》2007,218(1-3):1-7
The epithelium of upper respiratory tissues such as nasal mucosa forms a continuous barrier to a wide variety of exogenous
antigens. The epithelial barrier function is regulated in large part by the intercellular junctions, referred to as gap and
tight junctions. However, changes of gap and tight junctions during differentiation of human nasal epithelial (HNE) cells
are still unclear. In the present study, to investigate changes of gap and tight junctions during differentiation of HNE cells
in vitro, we used primary human HNE cells cocultured with primary human nasal fibroblast (HNF) cells in a noncontact system. In HNE
cells cocultured with HNF cells for 2 weeks, numerous elongated cilia-like structures were observed compared to those without
HNF cells. In the coculture, downregulation of Cx26 and upregulation of Cx30.3 and Cx31 were observed together with extensive
gap junctional intercellular communication. Furthermore, expression of the tight junction proteins claudin-1, claudin-4, occludin
and ZO-2 was increased. These results suggest that switching in expression of connexins and induction of tight junction proteins
may be closely associated with differentiation of HNE cells in
vitro and that differentiation of HNE cells requires unknown soluble factors secreted from HNF cells. 相似文献
245.
Ishikawa T Terai S Urata Y Marumoto Y Aoyama K Murata T Mizunaga Y Yamamoto N Nishina H Shinoda K Sakaida I 《Cell and tissue research》2007,327(3):463-470
We previously reported that fibroblast growth factor 2 (FGF2) facilitated the differentiation of transplanted bone marrow
cells (BMCs) into hepatocytes. Our earlier study also demonstrated that administration of FGF2 in combination with bone marrow
transplantation (BMT) synergistically activated tumor necrosis factor-alpha signaling and significantly improved liver function
and prognosis more than BMT alone. However, the way that it affected the extracellular matrix remained unclear. Here, we investigated
the effect of FGF2 treatment together with BMT on liver fibrosis in mice treated with carbon tetrachloride (CCl4). Transplantation of BMCs and concurrent treatment with FGF2 caused a statistically significant reduction in CCl4-induced liver fibrosis that was accompanied by strong expression of matrix metalloproteinase 9 as compared with FGF2-only
treatment or BMT alone. Moreover, in this process, the proliferation of bone-marrow-derived cells was accelerated without
causing apoptosis. Thus, the administration of FGF2 in combination with BMT synergistically improves CCl4-induced liver fibrosis in mice. This treatment has the potential of being an effective therapy for patients with liver cirrhosis.
This study was supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (nos. 16390211
and 16590597) and for translational research from the Ministry of Health, Labor and Welfare (H-trans-5 and H17-Special-015). 相似文献
246.
NADP(H) Phosphatase Activities of Archaeal Inositol Monophosphatase and Eubacterial 3′-Phosphoadenosine 5′-Phosphate Phosphatase
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NADP(H) phosphatase has not been identified in eubacteria and eukaryotes. In archaea, MJ0917 of hyperthermophilic Methanococcus jannaschii is a fusion protein comprising NAD kinase and an inositol monophosphatase homologue that exhibits high NADP(H) phosphatase activity (S. Kawai, C. Fukuda, T. Mukai, and K. Murata, J. Biol. Chem. 280:39200-39207, 2005). In this study, we showed that the other archaeal inositol monophosphatases, MJ0109 of M. jannaschii and AF2372 of hyperthermophilic Archaeoglobus fulgidus, exhibit NADP(H) phosphatase activity in addition to the already-known inositol monophosphatase and fructose-1,6-bisphosphatase activities. Kinetic values for NADP+ and NADPH of MJ0109 and AF2372 were comparable to those for inositol monophosphate and fructose-1,6-bisphosphate. This implies that the physiological role of the two enzymes is that of an NADP(H) phosphatase. Further, the two enzymes showed inositol polyphosphate 1-phosphatase activity but not 3′-phosphoadenosine 5′-phosphate phosphatase activity. The inositol polyphosphate 1-phosphatase activity of archaeal inositol monophosphatase was considered to be compatible with the similar tertiary structures of inositol monophosphatase, fructose-1,6-bisphosphatase, inositol polyphosphate 1-phosphatase, and 3′-phosphoadenosine 5′-phosphate phosphatase. Based on this fact, we found that 3′-phosphoadenosine 5′-phosphate phosphatase (CysQ) of Escherichia coli exhibited NADP(H) phosphatase and fructose-1,6-bisphosphatase activities, although inositol monophosphatase (SuhB) and fructose-1,6-bisphosphatase (Fbp) of E. coli did not exhibit any NADP(H) phosphatase activity. However, the kinetic values of CysQ and the known phenotype of the cysQ mutant indicated that CysQ functions physiologically as 3′-phosphoadenosine 5′-phosphate phosphatase rather than as NADP(H) phosphatase. 相似文献
247.
Yoshiharu Inoue Wataru Nomura Yoko Takeuchi Takumi Ohdate Shogo Tamasu Atsushi Kitaoka Yoshifumi Kiyokawa Hiroshi Masutani Kazuo Murata Yoshinori Wakai Shingo Izawa Junji Yodoi 《Applied microbiology》2007,73(5):1672-1675
Thioredoxin, an antioxidant protein, is a promising molecule for development of functional foods because it protects the gastric mucosa and reduces the allergenicity of allergens. To establish a method for obtaining an ample amount of yeast thioredoxin, we found here that thioredoxin is released from Saccharomyces cerevisiae by treatment with 20% ethanol. We also found that Japanese sake contains a considerable amount of thioredoxin. 相似文献
248.
Murata Y Tsuruzoe K Kawashima J Furukawa N Kondo T Motoshima H Igata M Taketa K Sasaki K Kishikawa H Kahn CR Toyonaga T Araki E 《Biochemical and biophysical research communications》2007,364(2):301-307
Insulin receptor substrate-1 (IRS-1) is the major substrate of both the insulin receptor and the IGF-1 receptor. In this study, we created IRS-1 transgenic (IRS-1-Tg) mice which express human IRS-1 cDNA under control of the mouse IRS-1 gene promoter. In the IRS-1-Tg mice, IRS-1 mRNA expression was significantly increased in almost all tissues, but its protein expression was increased in very limited tissues (epididymal fat and skeletal muscle). IRS-1-Tg mice showed glucose intolerance and significantly enlarged epididymal fat mass, as well as elevated serum TNF-α concentrations. Importantly insulin signaling was significantly attenuated in the liver of IRS-1-Tg mice, which may contribute to the glucose intolerance. Our results suggest that excess IRS-1 expression may not provide a beneficial impact on glucose homeostasis in vivo. 相似文献
249.
250.
Ikejiri M Ohshima T Kato K Toyama M Murata T Shimotohno K Maruyama T 《Bioorganic & medicinal chemistry》2007,15(22):6882-6892
On the basis of our previous study on antiviral agents against the severe acute respiratory syndrome (SARS) coronavirus, a series of nucleoside analogues whose 5'-hydroxyl groups are masked by various protective groups such as carboxylate, sulfonate, and ether were synthesized and evaluated to develop novel anti-hepatitis C virus (HCV) agents. Among these, several 5'-O-masked analogues of 6-chloropurine-2'-deoxyriboside (e.g., 5'-O-benzoyl, 5'-O-p-methoxybenzoyl, and 5'-O-benzyl analogues) were found to exhibit effective anti-HCV activity. In particular, the 5'-O-benzoyl analogue exhibited the highest potency with an EC(50) of 6.1 microM in a cell-based HCV replicon assay. Since the 5'-O-unmasked analogue (i.e., 6-chloropurine-2'-deoxyriboside) was not sufficiently potent (EC(50)=47.2 microM), masking of the 5'-hydroxyl group seems to be an effective method for the development of anti-HCV agents. Presently, we hypothesize two roles for the 5'-O-masked analogues: One is the role as an anti-HCV agent by itself, and the other is as a prodrug of its 5'-O-demasked (deprotected) derivative. 相似文献