排序方式: 共有143条查询结果,搜索用时 46 毫秒
51.
Nagahama H Oshima T Mori H Matsumoto K Hara H 《The Journal of General and Applied Microbiology》2007,53(2):143-151
An Escherichia coli pgsA null mutant deficient in acidic phospholipids shows a thermosensitive cell lysis phenotype because of activation of the Rcs phosphorelay signal transduction system. We conducted a DNA microarray analysis with special attention to the genes affected by growth temperature in the mutant deficient in acidic phospholipids. Among the genes identified as highly expressed at high temperature in the pgsA null mutant, the osmB gene was shown to be dependent on the Rcs system for the high expression by dot blot hybridization. Induction of the cloned osmB in the pgsA null mutant caused the thermosensitive defect even in the absence of the Rcs system. Although the deletion of osmB did not suppress the thermosensitivity in the presence of the Rcs system, indicating a multifactorial nature of the deleterious effect of the Rcs activation, we suggest that the osmB hyperexpression is one of the causes of the Rcs-dependent lysis phenotype of the pgsA null mutant. 相似文献
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Kitagawa Masanari; Ara Takeshi; Arifuzzaman Mohammad; Ioka-Nakamichi Tomoko; Inamoto Eiji; Toyonaga Hiromi; Mori Hirotada 《DNA research》2005,12(5):291-299
Based on the genomic sequence data of Escherichia coli K-12strain, we have constructed a complete set of cloned individualgenes encoding Histidine-tagged proteins with or without GFPfused for functional genomic analysis. Each clone encodes aprotein of predicted ORF attached by Histidines and seven spaceramino acids at the N-terminal end, and five spacer amino acidsand GFP at the C-terminal end. SfiI restriction sites are generatedat both the N- and C-terminal boundaries of ORF upon cloning,which enables easy transfer of ORF to other vector systems bycutting with SfiI. Expression of cloned ORF is under the controlof an IPTG-inducible promoter, which is strictly repressed bylacIq repressor gene product. The set of cloned ORFs describedhere should provide unique resources for systematic functionalgenomic approaches including (i) construction of DNA microarray,(ii) production and purification of proteins, (iii) analysisof protein localization by monitoring GFP fluorescence and (iv)analysis of proteinprotein interaction. 相似文献
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Butland G Babu M Díaz-Mejía JJ Bohdana F Phanse S Gold B Yang W Li J Gagarinova AG Pogoutse O Mori H Wanner BL Lo H Wasniewski J Christopolous C Ali M Venn P Safavi-Naini A Sourour N Caron S Choi JY Laigle L Nazarians-Armavil A Deshpande A Joe S Datsenko KA Yamamoto N Andrews BJ Boone C Ding H Sheikh B Moreno-Hagelseib G Greenblatt JF Emili A 《Nature methods》2008,5(9):789-795
Physical and functional interactions define the molecular organization of the cell. Genetic interactions, or epistasis, tend to occur between gene products involved in parallel pathways or interlinked biological processes. High-throughput experimental systems to examine genetic interactions on a genome-wide scale have been devised for Saccharomyces cerevisiae, Schizosaccharomyces pombe, Caenorhabditis elegans and Drosophila melanogaster, but have not been reported previously for prokaryotes. Here we describe the development of a quantitative screening procedure for monitoring bacterial genetic interactions based on conjugation of Escherichia coli deletion or hypomorphic strains to create double mutants on a genome-wide scale. The patterns of synthetic sickness and synthetic lethality (aggravating genetic interactions) we observed for certain double mutant combinations provided information about functional relationships and redundancy between pathways and enabled us to group bacterial gene products into functional modules. 相似文献
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Makoto Moro Ryuzo Torii Hajime Ishii Yoshikuni Tanioka Yoichi Inada Masami Kojima Hirotada Tsujii 《Primates; journal of primatology》2001,42(4):375-390
We investigated the relationship between the menstrual cycle and hormone levels in cynomolgus monkeys, and developed a sulpiride-induced
hyperprolactinemic anovulation model. On this study, we demonstrated the usefulness of the commercial human prolactin immunoradiometric
assay kit for the measurement of cynomolgus monkey serum samples. In the normal menstrual cycle of the cynomolgus monkey,
serum prolactin concentrations were not significantly different between luteal and follicular phases. However, the serum prolactin
concentration tended to elevate at the ovulation stage. And serum progesterone began to increase after an estradiol surge,
and then declined before the ensuing preovulatory rise in estradiol. During the luteal phase, the serum concentration of progesterone
was elevated. Moreover, we aimed to develop an anovulation model, using sulpiride-induced hyperprolactinemia in the cynomolgus
monkey. The serum prolactin level gradually increased during the twice-daily administration of sulpiride, and the drug produced
as big a response at 5 mg/kg. In this study, the length of the menstrual cycle was approximately 29 days in normal cynomolgus
monkeys. When treatment with sulpiride had been continued for more than one month, serum progesterone and estradiol levels
fell to within the range seen in the follicular phase of the normal cycle, and the absence of ovulation was recognized by
laparoscopy. Moreover, in this period we found that amenorrhea or anovulatory menstruation in the experimental animals. We
could produce an anovulatory model induced by sulpiride repeatedly administered over a long time period. Our findings suggest
that the cynomolgus monkey is useful as a endocrinological model that uses prolactin as a parameter and as an anovulatory
model; thus, it could be a useful model for the hyperprolactinemic amenorrhea and/or anovulation seen in humans. 相似文献
57.
Mitsuoki Kawano Shigehiko Kanaya Taku Oshima Yasushi Masuda Takeshi Ara Hirotada Mori 《DNA research》2002,9(1):1-10
In the present study, we developed a method for detecting sequences whose similarity to a target sequence is statistically significant and we examined the distribution of these sequences in the E. coli K-12 genome. Target sequences examined are as follows: (i) short repeat: Crossover hot-spot instigator (Chi) sequence, replication termination (Ter) sequence, and DnaA binding sequence (DnaA box); (ii) potential stem-loop structure repeats: palindromic unit (PU), boxC sequences, and intergenic repeat unit (IRU); (iii) potential RNA coding repeats: rRNAs, PAIR, TRIP, and QUAD; and (iv) potential protein coding repeats: insertion elements (ISs) and Long Direct Repeats (LDRs). We also examined the distribution of these sequences on leading and lagging strands. We obtained another four statistically significant LDR sequences with more than 187 bp matched to LDR-A near the LDR loci, suggesting that these regions might be used as high recombination hot spots for LDR. Adaptation of individual LDRs to E. coli genome is also discussed on the basis of codon usage. 相似文献
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Responses of the central metabolism in Escherichia coli to phosphoglucose isomerase and glucose-6-phosphate dehydrogenase knockouts 下载免费PDF全文
The responses of Escherichia coli central carbon metabolism to knockout mutations in phosphoglucose isomerase and glucose-6-phosphate (G6P) dehydrogenase genes were investigated by using glucose- and ammonia-limited chemostats. The metabolic network structures and intracellular carbon fluxes in the wild type and in the knockout mutants were characterized by using the complementary methods of flux ratio analysis and metabolic flux analysis based on [U-(13)C]glucose labeling and two-dimensional nuclear magnetic resonance (NMR) spectroscopy of cellular amino acids, glycerol, and glucose. Disruption of phosphoglucose isomerase resulted in use of the pentose phosphate pathway as the primary route of glucose catabolism, while flux rerouting via the Embden-Meyerhof-Parnas pathway and the nonoxidative branch of the pentose phosphate pathway compensated for the G6P dehydrogenase deficiency. Furthermore, additional, unexpected flux responses to the knockout mutations were observed. Most prominently, the glyoxylate shunt was found to be active in phosphoglucose isomerase-deficient E. coli. The Entner-Doudoroff pathway also contributed to a minor fraction of the glucose catabolism in this mutant strain. Moreover, although knockout of G6P dehydrogenase had no significant influence on the central metabolism under glucose-limited conditions, this mutation resulted in extensive overflow metabolism and extremely low tricarboxylic acid cycle fluxes under ammonia limitation conditions. 相似文献
59.
Role of phosphoenolpyruvate in the NADP-isocitrate dehydrogenase and isocitrate lyase reaction in Escherichia coli 下载免费PDF全文
Phosphoenolpyruvate inhibited Escherichia coli NADP-isocitrate dehydrogenase allosterically (Ki of 0.31 mM) and isocitrate lyase uncompetitively (Ki' of 0.893 mM). Phosphoenolpyruvate enhances the uncompetitive inhibition of isocitrate lyase by increasing isocitrate, which protects isocitrate dehydrogenase from the inhibition, and contributes to the control through the tricarboxylic acid cycle and glyoxylate shunt. 相似文献
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A 718-kb DNA Sequence of the Escherichia coli K-12 Genome Corresponding to the 12.7-28.0 min Region on the Linkage Map 总被引:3,自引:0,他引:3
Oshima Taku; Aiba Hiroji; Baba Tomoya; Fujita Katsutoshi; Hayashi Kouji; Honjo Atsuko; Ikemoto Keiichi; Inada Toshifumi; Itoh Takeshi; Kajihara Miwako; Kanai Kiyotaka; Kashimoto Kaoru; Kimura Shigenobu; Kitagawa Masanari; Makino Kouzou; Masuda Shinji; Miki Takeyoshi; Mizobuchi Kiyoshi; Mori Hirotada; Motomura Kouji; Nakamura Yoshikazu; Nashimoto Hiroko; Nishio Yoshitaka; Saito Noriko; Sampei Gen-ichi; Seki Yasushi; Tagami Hideaki; Takemoto Keiko; Wada Chieko; Yamamoto Yoshihiro; Yano Minoru; Horiuchi Takashi 《DNA research》1996,3(3):137-155
The 718,122 base pair (bp) sequence of the Escherichia coliK-12 genome corresponding to the region from 12.7 to 28.0 minuteson the genetic map is described. This region contains at least682 potential open reading frames, of which 278 (41%) have beenpreviously identified, 147 (22%) were homologous to other knowngenes, 138 (20%) are identical or similar to the hypotheticalgenes registered in databases, and the remaining 119 (17%) didnot show a significant similarity to any other gene. In thisregion, we assigned a cluster of cit genes encoding multienzymecitrate lyase, two clusters of fimbrial genes and a set of lysogenicphage genes encoding integrase, excisionase and repressor inthe e14 genetic element. In addition, a new valine tRNA gene,designated valZ, and a family of long directly repeated sequences,LDR-A, -B and -C, were found. 相似文献