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891.
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Wenhua L Ruming Z Zhixiong X Xiangdong C Ping S 《Biological trace element research》2003,94(2):167-177
Rare earth elements have been emitted into the environment largely as fertilizer components. This has caused much fear about
whether they would influence our environment, especially on the metabolism and genetics of microorganisms. In this article,
the trivalent ion of a rare earth element, lanthanum, was studied for the effects on growth, transformation, and gene expression
of Escherichia coli. The results showed that La3+ at concentrations from 50 to 150 μg/mL stimulated the endogenic metabolism and ectogenic metabolism, but had few effects
on gene expression. La3+ at lower concentrations from 0.5 to 30 μg/mL inhibit intensively E. coli-absorbing external DNA, decreasing the transformation efficiency. It is also supported by observations using transmission
electron microscopy. Our results are significant in understanding the function of rare earth elements to microorganisms and
assessing the risk of application of rare earth compounds. 相似文献
895.
In preparing intracellular microbial samples for one- or two-dimensional electrophoresis, trichloroacetic acid (TCA) precipitation is frequently used to remove interfering compounds. Solubilization of TCA precipitate typically requires the addition of a number of chaotropes or detergents, in a multistep process, that requires hours to carry out. In this study, a simple, rapid, one-step method to solubilize TCA precipitated proteins is presented. Precipitated proteins are pretreated with 0.2 M NaOH for less than 5 min, followed by addition of standard sample solubilization buffer (SSSB). When compared to solubilization with SSSB alone, NaOH pretreatment of TCA-precipitated intracellular protein from Aspergillus oryzae and Escherichia coli shows an approximate 5-fold increase in soluble protein. In addition, two-dimensional gel electrophoresis on resolubilized proteins shows an equivalent number of proteins in samples with and without NaOH pretreatment. 相似文献
896.
Martin MJ Yin D Adams C Houtz J Shen J Chong AS Sharma A Byrne GW Wiseman BS Logan JS 《Cloning and stem cells》2003,5(2):117-121
Nuclear transfer technology allows for the reprogramming of somatic cells, and the production of embryonic stem cells and animals that are genetically identical in terms of nuclear DNA to the parental somatic cell. It is assumed that these products of nuclear transfer technology will be immunologically compatible to each other in spite of the fact that there are data that show differences in the expression patterns and phenotypes between animals produced by nuclear transfer. We have produced a series of cloned pigs from embryonic fibroblasts. Microsatellite analysis was used to confirm that the clones were genetically identical. Skin transplants were performed to assess immunological reactivity. Skin transplants between genetically identical cloned pigs were accepted, whereas third party grafts were rejected. Histological analysis of the grafts showed edema and mononuclear cell infiltrates in the recipient's skin in rejected grafts and not in grafts that were accepted. Our data supports the notion that genetically identical cloned pigs are immunologically compatible. 相似文献
897.
Proteomics approach to identify wound-response related proteins from rice leaf sheath 总被引:4,自引:0,他引:4
In order to avoid the complex conditions of the intact plant for simple analysis of proteins in wound-response stress, we used the detached rice leaf sheath which is a very active part of the rice seedling. Proteins were extracted from rice leaf sheath at 0, 12, 24, 48 h after cutting and separated by two-dimensional (2-D) polyacrylamide gel electrophoresis. Changes in differentially displayed proteins were found in leaf sheaths after cutting in the 0-48 h time course. Ten proteins were up-regulated, while 19 proteins were down-regulated compared with those on the four 2-D gels. Among them, 14 proteins were analyzed by N-terminal, or internal amino acid sequence. The clear functions of nine proteins could be identified. Six proteins did not yield amino acid sequence information due to their blocked N-termini. Furthermore, 11 proteins were determined by matrix-assisted laser desorption/ionization-time of flight mass spectrometry, and identified protein database matching. It was shown that the down-regulated proteins were calreticulin (nos. 5, 6), histone H1 (no. 15) and hemoglobin (no. 17), putative peroxidase (no. 19); the up-regulated proteins were Bowman-Birk trypsin inhibitor (no. 23), putative receptor-like protein kinase (nos. 24, 25), calmodulin-related protein (no. 26), small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (no. 27), mannose-binding rice lectin (nos. 28, 29). Among all the above proteins, four (nos. 23, 24, 25, 26) have been confirmed to be wound-response proteins. The others cannot be excluded as also being related to wound-responses, such as the signal transduction-related proteins (nos. 5, 6), photosynthesis-related protein (no. 27), and stress-response proteins (nos. 19, 28, 29). This is the first time protein changes in response to wounding in rice leaf sheath have been shown. 相似文献
898.
Arabidopsis AtGPAT1, a member of the membrane-bound glycerol-3-phosphate acyltransferase gene family,is essential for tapetum differentiation and male fertility 总被引:3,自引:0,他引:3 下载免费PDF全文
Membrane-bound glycerol-3-phosphate acyltransferase (GPAT; EC 2.3.1.15) mediates the initial step of glycerolipid biosynthesis in the extraplastidic compartments of plant cells. Here, we report the molecular characterization of a novel GPAT gene family from Arabidopsis, designated AtGPAT. The corresponding polypeptides possess transmembrane domains and GPAT activity when expressed heterologously in a yeast lipid mutant. The functional significance of one isoform, AtGPAT1, is the focus of the present study. Disruption of the AtGPAT1 gene causes a massive pollen development arrest, and subsequent introduction of the gene into the mutant plant rescues the phenotype, illustrating a pivotal role for AtGPAT1 in pollen development. Microscopic examinations revealed that the gene lesion results in a perturbed degeneration of the tapetum, which is associated with altered endoplasmic reticulum profiles and reduced secretion. In addition to the sporophytic effect, AtGPAT1 also exerts a gametophytic effect on pollen performance, as the competitive ability of a pollen grain to pollinate is dependent on the presence of an AtGPAT1 gene. Deficiency in AtGPAT1 correlates with several fatty acid composition changes in flower tissues and seeds. Unexpectedly, however, a loss of AtGPAT1 causes no significant change in seed oil content. 相似文献
899.
Sun H Luo H Yu C Sun T Chen J Peng S Qin J Shen J Yang Y Xie Y Chen K Wang Y Shen X Jiang H 《Protein expression and purification》2003,32(2):302-308
Severe acute respiratory syndrome (SARS) is an acute respiratory illness, which has broken out in China. It has been known that SARS coronavirus (SARS_CoV) is a novel human coronavirus and is responsible for SARS infection. Belonging to one of the major proteins associated with SARS_CoV, SARS 3C-like protease (SARS_3CL(pro)) functions as a cysteine protease engaging in the proteolytic cleavage of the viral precursor polyprotein to a series of functional proteins required for coronavirus replication and is considered as an appealing target for designing anti-SARS agents. To facilitate the studies regarding the functions and structures of SARS_3CL(pro), in this report the synthetic genes encoding 3CL(pro) of SARS_CoV were assembled, and the plasmid was constructed using pQE30 as vector and expressed in Escherichia coli M15 cells. The highly yielded ( approximately 15mg/L) expressed protease was purified by use of NTA-Ni(2+) affinity chromatography and FPLC system, and its sequence was determined by LC/MS with the residue coverage of 46.4%. 相似文献
900.
Bcl-2 antisense oligodeoxynucleotide increases the sensitivity of leukemic cells to arsenic trioxide 总被引:3,自引:0,他引:3
Cell culture, tissue chemistry and flow cytometry were used to determine whether antisense bcl-2 oligodeoxynucleotides enhanced the sensitivity of leukemia cells to arsenic trioxide. A combination of arsenic trioxide with antisense bcl-2 oligodeoxynucleotides inhibited cell growth, induced apoptosis and induced bcl-2 protein expression in K562 and NB4 leukemic cells more significantly than either arsenic trioxide or the oligodeoxynucleotides on their own (P<0.01). Thus, bcl-2 antisense oligodeoxynucleotides increase the sensitivity of leukemic cells to arsenic trioxide. Combined use of the two agents could be a novel and attractive strategy in leukemia treatment. 相似文献