研究者詳細 - 山篠　貴史

論文 - 山篠　貴史

分割表示 118 件中 101 - 118 件目／全件表示 >>

Involvement of surface polysaccharides in the organic acid resistance of Shiga Toxin-producing Escherichia coli O157:H7. 査読有り

Barua S, Yamashino T, Hasegawa T, Yokoyama K, Torii K, Ohta M

Mol. Microbiol. 43 巻 ( 3 ) 頁： 629-640 2002年2月

記述言語：英語掲載種別：研究論文（学術雑誌）

In general, wild Escherichia coli strains can grow effectively under moderately acidic organic acid-rich conditions. We found that the Shiga Toxin-producing E. coli (STEC) O157:H7 NGY9 grows more quickly than a K-12 strain in Luria-Bertani (LB)-2-morpholinoethanesulphonic acid (MES) broth supplemented with acetic acid (pH 5.4). Hypothesizing that the resistance of STEC O157:H7 to acetic acid is as a result of a mechanism(s) other than those known, we screened for STEC mutants sensitive to acetic acid. NGY9 was subjected to mini-Tn5 mutagenesis and, from 50,000 colonies, five mutants that showed a clear acetic acid-sensitive phenotype were isolated. The insertion of mini-Tn5 in three mutants occurred at the fcl, wecA (rfe) and wecB (rffE) genes and caused loss of surface O-polysaccharide, loss of both O-polysaccharide and enterobacterial common antigen (ECA) and loss of ECA respectively. The other two mutants showed inactivation of the waaG (rfaG) gene but at different positions that caused a deep rough mutant with loss of the outer core oligosaccharide of lipopolysaccharide (LPS) as well as phenotypic loss of O-polysaccharide and ECA. With the introduction of plasmids carrying the fcl, wecA, wecB and waaG genes, respectively, all mutants were complemented in their production of O-polysaccharide and ECA, and normal growth was restored in organic acid-rich culture conditions. We also found that the growth of Salmonella LPS mutants Ra, Rb1, Rc, Rd1, Rd2 and Re was suppressed in the presence of acetic acid compared with that of the parents. These results suggest that the full expression of LPS (including O-polysaccharide) and ECA is indispensable to the resistance against acetic acid and other short chain fatty acids in STEC O157:H7 and Salmonella. To the best of our knowledge, this is a newly identified physiological role for O-polysaccharide and ECA as well as an acid resistance mechanism.

The APRR1/TOC1 quintet implicated in circadian rhythms of Arabidopsis thaliana: I. Characterization with APRR1-overexpressing plants. 査読有り

Makino S, Matsushika A, Kojima M, Yamashino T, Mizuno T

Plant Cell Physiol. 43 巻 ( 1 ) 頁： 58-69 2002年1月

記述言語：英語

Several Arabidopsis genes have been proposed to encode potential clock-associated components, including the Myb-related CCA1 and LHY transcription factors and a member of the novel family of pseudo response regulators (APRR1/TOC1). We previously showed that mRNAs of the APRR1/TOC1 family of genes start accumulating after dawn rhythmically and sequentially at approximately 2 h intervals in the order: APRR9--> APRR7-->APRR5-->APRR3-->APRR1/TOC1. Here we constructed APRR1-overexpressing (APRR1-ox) plants, and examined certain circadian profiles for APRRs, CCA1, LHY, GI, CCR2, and CAB2. The free-running circadian rhythms of the APRR1/TOC1 family of genes, including APRR1, were dampened in APRR1-ox plants. In particular, the light-inducible expression of APRR9 was severely repressed in APRR1-ox plants, suggesting that there is a negative APRR1-->APRR9 regulation. The free-running robust rhythm of CAB2 was also dampened in APRR1-ox. The circadian profiles of potential clock-associated genes, CCA1, LHY, GI, and CCR2 were all markedly altered in APRR1-ox, each in characteristic fashion. To gain further insight into the molecular function of APRR1, we then identified a novel Myc-related bHLH transcription factor, which physically associated with APRR1. This protein (named PIL1) is similar in its amino acid sequence to PIF3, which has been identified as a phytochrome-interacting transcription factor. These results are discussed in relation to the current idea that APRR1 (TOC1) plays a role within, or close to, the Arabidopsis central oscillator.

An Arabidopsis histidine-containing phosphotransfer (HPt) factor implicated in phosphorelay signal transduction: overexpression of AHP2 in plants results in hypersensitiveness to cytokinin 査読有り

Suzuki T, Ishikawa K, Yamashino T, Mizuno T

Plant Cell Physiol. 43 巻 ( 1 ) 頁： 123-129 2002年1月

記述言語：英語掲載種別：研究論文（学術雑誌）

Histidine-containing phosphotransfer (HPt) factors from Arabidopsis thaliana, designated as AHPs, function most likely in concert with histidine (His)-kinases (HKs) and response regulators (RRs) in certain multistep histidine (His)-->aspartate (Asp) phosphorelays that are involved in the signal transduction mechanisms, by which plant cells appear to respond to certain hormonal stimuli, including cytokinin. Although some previous in vitro results from studies on Arabidopsis AHPs (AHP1 to AHP5) supported this hypothesis, it has not yet been proven. To this end, here we constructed transgenic plants that contained the AHP2 protein in a considerably higher amount than in wild-type plants. Such AHP2-overexpressing young seedlings were examined in comparison with wild-type plants, with special reference to hormone responses; particularly, their inhibitory effects on root elongation of plants grown on agar-plates, and also hypocotyl elongation of etiolated seedlings grown in the dark. The results of this study suggested that AHP2-overexpressing plants showed a characteristic phenotype of cytokinin-hypersensitive. These in vivo observations were best interpreted by assuming that the AHP factor(s) is somehow implicated, if not directly, in a cytokinin-mediated His-->Asp phosphorelay signaling in Arabidopsis.

The APRR1/TOC1 quintet implicated in circadian rhythms of Arabidopsis thaliana: II. Characterization with CCA1-overexpressing plants 査読有り

Matsushika A, Makino S, Kojima M, Yamashino T, Mizuno T

Plant Cell Physiol. 43 巻 ( 1 ) 頁： 118-122 2002年1月

記述言語：英語掲載種別：研究論文（学術雑誌）

We previously identified a novel class of proteins, named pseudo-response regulators (APRRs) in Arabidopsis thaliana, each of which (APRR1, APRR3, APRR5, APRR7, and APRR9) has an intriguing structural design containing an N-terminal pseudo receiver domain and a C-terminal CONSTANS motif. Among them, APRR1 is identical to TOC1, previously proposed to be a candidate component of an Arabidopsis circadian clock. Intriguingly, expressions of the APRR1/TOC1 family of genes are under control of coordinate circadian rhythms at the level of transcription, in the manner that each APRR-transcript starts accumulating sequentially after dawn with 2 to 3 h intervals in the order: APRR9-->APRR7-->APRR5-->APRR3-->APRR1/TOC1. Here we examined this circadian-related event, "circadian waves of the APRR1/TOC1 quintet", by employing CCA1-overexpression (CCA1-ox) transgenic plants, based on the fact that CCA1 is a well-characterized and the most plausible oscillator component. It was found that aberrant overexpression of the CCA1 gene severely perturbed free-running and sequential rhythms of the APRR1/TOC1 family of genes. In the accompanying paper, it was shown that overexpression of APRR1 also results in a marked alteration of the CCA1 circadian rhythm, and vice versa. Taken together, it was suggested that there are intimate and mutual links between these two types of circadian-associated components (APRRs and CCA1).

Resolution of Escherichia coli O157:H7 that contaminated radish sprouts in two outbreaks by two-dimensional gel electrophoresis.

"Yokoyama K, Iinuma Y, Kawano Y, Nakano M, Kawagishi M, Yamashino T, Hasegawa T, Ohta M"

Curr. Microbiol. 43 巻 ( 5 ) 頁： 311-315 2001年11月

Characterization of the RcsC-->YojN-->RcsB phosphorelay signaling pathway involved in capsular synthesis in Escherichia coli.

"Chen MH, Takeda S, Yamada H, Ishii Y, Yamashino T, Mizuno T"

Biosci. Biotechnol. Biochem. 65 巻 ( 10 ) 頁： 2364-2367 2001年10月

The Arabidopsis AHK4 histidine kinase is a cytokinin-binding receptor that transduces cytokinin signals across the membrane.

"Yamada H, Suzuki T, Terada K, Takei K, Ishikawa K, Miwa K, Yamashino T, Mizuno T"

Plant Cell Physiol. 42 巻 ( 9 ) 頁： 1017-1023 2001年9月

Postantibiotic suppression effect of macrolides on the expression of flagellin in Pseudomonas aeruginosa and Proteus mirabilis.

"Kawamura-Sato K, Iinuma Y, Hasegawa T, Yamashino T, Ohta M."

J. Infect. Chemother. 7 巻 ( 1 ) 頁： 51-54 2001年3月

Proteolytic cleavage of staphylococcal exoproteins analyzed by two-dimensional gel electrophoresis.

"Kawano Y, Kawagishi M, Nakano M, Mase K, Yamashino T, Hasegawa T, Ohta M."

Microbiol. Immunol. 45 巻 ( 4 ) 頁： 285-90 2001年1月

Production of shiga toxin by Escherichia coli measured with reference to the membrane vesicle-associated toxins.

"Yokoyama K, Horii T, Yamashino T, Hashikawa S, Barua S, Hasegawa T, Watanabe H, Ohta M."

FEMS Microbiol. Lett. 192 巻 ( 1 ) 頁： 139-144 2000年11月

Effect of subinhibitory concentrations of macrolides on expression of flagellin in Pseudomonas aeruginosa and Proteus mirabilis.

"Kawamura-Sato K, Iinuma Y, Hasegawa T, Horii T, Yamashino T, Ohta M."

Antimicrob. Agents Chemother. 44 巻 ( 10 ) 頁： 2869-2872 2000年10月

Rapid isolation and identification of staphylococcal exoproteins by reverse phase capillary high performance liquid chromatography-electrospray ionization mass spectrometry.

"Kawano Y, Ito Y, Yamakawa Y, Yamashino T, Horii T, Hasegawa T, Ohta M."

FEMS Microbiol. Lett. 189 巻 ( 1 ) 頁： 103-108 2000年8月

Deletion of the yhhP gene results in filamentous cell morphology in Escherichia coli.

Ishii Y, Yamada H, Yamashino T, Ohashi K, Katoh E, Shindo H, Yamazaki T, Mizuno T

Biosci. Biotechnol. Biochem. 64 巻 ( 4 ) 頁： 799-807 2000年4月

Firm adherence of Staphylococcus aureus and Staphylococcus epidermidis to human hair and effect of detergent treatment.

"Mase K, Hasegawa T, Horii T, Hatakeyama K, Kawano Y, Yamashino T, Ohta M."

Microbiol. Immunol. 44 巻 ( 8 ) 頁： 653-656 2000年1月

The yhhP gene encoding a small ubiquitous protein is fundamental for normal cell growth of Escherichia coli.

"Yamashino T, Isomura M, Ueguchi C, Mizuno T"

J. Bacteriol. 180 巻 ( 8 ) 頁： 2257-61 1998年4月

Quantitative control of the stationary phase-specific sigma factor σ^s, in Escherichia coli : involvement of the nucleoid protein H-NS

EMBO J. 14 巻頁： 594-602 1995年

An analogue of the Dna J molecular chaperone whose expression is controlled by σ^s during the stationary phase and phosphate starvation in Escherichia coli

Mol. Microbiol. 13 巻頁： 475-483 1994年

Expression of the Escherichia coli Dimorphic Glutamic Acid Decarboxylases is Regulated by the Nucleoid Protein H-NS 査読有り

Biosci. Biotech. Biochem. 57 巻頁： 1568-1569 1993年

　前のページ - 次のページ　

<山篠 貴史>

論文 - 山篠 貴史

<山篠　貴史>

論文 - 山篠　貴史