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111.
Toshikazu Takesawa Minako Ito Hiroyuki Kanzaki Nanako Kameya Ikuo Nakamura 《Molecular breeding : new strategies in plant improvement》2002,9(2):93-101
To develop a rice cultivar that would be suitable for direct-seedingcultivation in cooler temperate regions, we generated transgenic rice plants inwhich a rice encoding a -class glutathioneS-transferase (GST) under the control of a maize ubiquitinpromoter. GSTs have been suggested to be responsible for tolerance to variousstresses such as cold, salt and drought by detoxification of xenobioticcompounds and reactive oxygen species. A total of 87 R0 transgenicrice plants harboring a chimeric GST gene were generatedusing Agrobacterium mediated transformation. ThreeR2 lines homozygous for the transgene were assayed for GST activityand had higher GST and glutathione peroxidase activities thannon-transformants.Seedlings of the transgenic lines demonstrated greatly enhanced germination andgrowth rates at low temperature grown under submergence. The GST transgeniclines should be useful for breeding rice cultivars suitable for direct-seedingcultivation in cooler temperate regions. 相似文献
112.
Inhibition of catalase activity by oxidative stress and its relationship to salicylic acid accumulation in plants 总被引:15,自引:0,他引:15
Ie-Sung Shim Yukie Momose Akihiro Yamamoto Dea-Wook Kim Kenji Usui 《Plant Growth Regulation》2003,39(3):285-292
The decrease in catalase activity and its relationship to change in salicylic acid content were investigated in rice, wheat, and cucumber seedlings exposed to oxidative stresses. A decrease in chlorophyll fluorescence (F/Fm), measured as an indicator of the oxidative stress, and a drop in catalase activity were observed following treatment with NaCl in all plant seedlings tested . Furthermore, such decreases in F/Fm and catalase activity were also observed under low temperature conditions in both rice cultivars, whereas the degrees of decrease were dependent on their low temperature tolerance . Although the content of salicylic acid increased in rice seedlings stressed by NaCl treatment, it was inversely correlated with the decrease in the catalase activity . Such a relationship between the decrease in catalase activity and increase in salicylic acid content was confirmed with paraquat treatment of the rice seedlings . These results suggested that the fall in catalase activity is a phenomenon occurring in many plant species under oxidative stress and is related to the accumulation of salicylic acid in oxidatively-stressed plants. 相似文献
113.
Marathe GK Harrison KA Murphy RC Prescott SM Zimmerman GA McIntyre TM 《Free radical biology & medicine》2000,28(12):203-1770
Oxidation of phospholipids results in chain-shortened fragments and oxygenated derivatives of polyunsaturated sn-2 fatty acyl residues, generating a myriad of phospholipid products. Certain oxidation products of phosphatidylcholine bind to and activate the human receptor for PAF, and these PAF-like lipids are potent, selective inflammatory mediators. Formation of PAF-like lipids is nonenzymatic and so their accumulation is unregulated. PAF-like lipids are produced in vivo in response to oxidative stresses and are responsible for attendant acute inflammatory responses. PAF-like lipids almost exclusively contain an ether-linked alkyl residue at the sn-1 position of the phosphatidylcholine backbone and molecular identification of these is facilitated by phospholipase A1 treatment to remove the bulk of the inactive phospholipids. The identity of biologically active species generated by oxidative fragmentation and oxidation can be elucidated by understanding relevant reactions leading to the formation of PAF-like lipids, and then their structure can be established by tandem mass spectrometry and chemical synthesis. 相似文献
114.
115.
TLHS1 is a class I low molecular weight heat-shock protein (LMW HSP) of tobacco (Nicotiana tabacum). For a functional study of TLHS1, a recombinant DNA coding for TLHS1 with a hexahistidine tag at the aminoterminus was constructed and expressed in Escherichia coli. An expressed fusion protein, H6TLHS1, was purified using a Ni2+ affinity column and a Sephacryl S400 HR column. A polyclonal antibody against H6TLHS1 was produced to follow the fate of H6TLHS1 in E. coli. The fusion protein in E. coli maintained its solubility at a temperature of up to 90°C and most of the proteins in the E. coli cell lysate with H6TLHS1 were prevented from thermally induced aggregation at up to 90°C. We compared the viability of E. coli cells expressing H6TLHS1 to the E. coli cells without H6TLHS1 at a temperature of 50°C. After 8 h of high temperature treatment, E. coli cells with H6TLHS1 survived about three thousand times more than the bacterial cells without H6TLHS1. These results showed that a plant class I LMW HSP, TLHS1, can protect proteins of E. coli from heat denaturation, which could lead to a higher survival rate of the bacterial cells at high temperature. 相似文献
116.
Vrba J 《FEMS microbiology ecology》2000,33(1):81-84
The recent paper of Sherr and Sherr on detecting low-affinity beta-glucosaminidase activity in several marine microbes extends current knowledge about hydrolytic enzyme activities in natural aquatic systems. However, their conclusions regarding the whole-cell assay with MUF-N-acetyl-beta-D-glucosaminide (MUF-[GlcNAc]) cannot be accepted. First, we explicitly demonstrate a strong correlation between extracellular activities of the high-affinity enzymes and grazing rates of bacterivorous protists. Therefore, the assay can still be recommended for the estimation of total protistan grazing on prokaryotic picoplankton. Second, the ability of many aquatic organisms to produce enzymes which cleave fluorogenic substrates, such as MUF-[GlcNAc] and/or MUF-beta-D-N,N',N"-triacetylchitotriose (MUF-[GlcNAc](3)), has been well-documented during the last decade. Thus, neither of the two substrates may be considered as exclusively specific for targeting either lysozymes or beta-N-acetylhexosaminidases. 相似文献
117.
Bruno Notarnicola Gjalt Huppes Nico W. van den Berg 《The International Journal of Life Cycle Assessment》1998,3(5):289-300
LCA aims to help direct decisions in an environmentally sustainable direction. It indicates the environmental effects of choices
and evaluates these against this background. Approaches to evaluation in LCA differ substantially, related to the way of modelling
environmental effects and to the way these effects are combined into an overall judgement on alternative options. Several
approaches are now operational, which are linked to different paradigms in decision making. It is shown that the choice of
paradigm is quite decisive on the outcome of the analysis. Also within similar paradigms, different methods now operational
may lead to different outcomes. These latter differences may be alleviated more easily than those related to paradigmatic
choices, as they are partly a matter of refinement, and they partly result from legitimate differences in subjective priorities.
The more basic paradigmatic differences can hardly be bridged. The practical relevancy of the subject is proven by applying
different operational methods to one case, showing widely differing outcomes. The paradigm behind evaluating environmental
effects is either values based, directly or through policy decisions, or economics based, as individual preferences measured
in the monetary terms of willingness-to-pay. Accordingly, the different methods are “policy-oriented” or “monetary”. It may
be doubted if the differences between these can be overcome in standardisation. 相似文献
118.
肝素已经普遍用于冠状动脉介入术中,但是由于在应用过程中抗凝效果个体差异大、出血风险相对较高、并发症等问题的日益显现,已经引起了医生们的注意。相对而言,低分子肝素具有抗凝作用强、出血风险低、并发症发生率相对较低、无需实验室监测等优点,进而越来越广泛的在冠状动脉介入术中担当重要角色。普通肝素与低分子肝素在冠状动脉介入术中的有效性与安全性的比较是值得我们去探讨的,知道普通肝素与低分子肝素的优缺点后,可使我们在冠状动脉介入术中更好的选择抗凝药物,使手术的成功率大大提高,降低术后并发症的发生,减轻患者的痛苦。本文结合普通肝素与低分子肝素的药理作用及相关临床研究的结果,分析比较了普通肝素与低分子肝素在冠状动脉介入术中的有效性与安全性。 相似文献
119.
目的:观察低分子肝素联合丹参注射液治疗急性ST段抬高型心肌梗死的临床疗效及安全性。方法:按照随机原则将78例急性心肌梗死患者分成两组,在常规溶栓治疗的基础上,其中对照组39人采用低分子肝素治疗,治疗组患者在对照组治疗的基础上给予丹参注射液治疗,对两组临床费用、住院时间和冠脉再通进行评价。结果:治疗组的临床费用、住院时间和冠脉再通与对照组相比,有统计学差异(P0.05)。结论:低分子肝素联合丹参注射液治疗急性心肌梗死的临床疗效确切,值得临床推广。 相似文献
120.
Neelagandan Kamariah Sathya Moorthy Ponnuraj Balasubramanian Moovarkumudalvan Mondikalipudur Nanjappa Gounder Ponnuswamy 《Biochemical and biophysical research communications》2014
Hemoglobin (Hb) is in equilibrium between low affinity Tense (T) and high affinity Relaxed (R) states associated with its unliganded and liganded forms, respectively. Mammalian species can be classified into two groups on the basis of whether they express ‘high’ and ‘low’ oxygen affinity Hbs. Although Hbs from former group have been studied extensively, a limited number of structural studies have been performed for the low oxygen affinity Hbs. Here, the crystal structure of low oxygen affinity sheep methemoglobin (metHb) has been determined to 2.7 Å resolution. Even though sheep metHb adopts classical R state like quaternary structure, it shows localized quaternary and tertiary structural differences compared with other liganded Hb. The critical group of residues in the “joint region”, shown as a major source of quaternary constraint on deoxyHb, formed unique interactions in the α1β2/α2β1 interfaces of sheep metHb structure. In addition, the constrained β subunits heme environment and the contraction of N-termini and A-helices of β subunits towards the molecular dyad are observed for sheep metHb structure. These observations provide the structural basis for a low oxygen affinity and blunt response to allosteric effector of sheep Hb. 相似文献