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385 results on '"Ikeda, Tsukasa"'

15. The plant pathogen Pantoea ananatis produces N-acylhomoserine lactone and causes center rot disease of onion by quorum sensing

Author

Morohoshi, Tomohiro, Nakamura, Yuta, Yamazaki, Go, Ishida, Akio, Kato, Norihiro, and Ikeda, Tsukasa

Subjects
Enterobacter -- Physiological aspects, Enterobacteriaceae -- Physiological aspects, Quorum sensing -- Health aspects, Bacteria, Pathogenic -- Physiological aspects, Plant diseases -- Causes of, Onions -- Diseases, Biological sciences
Abstract

A number of gram-negative bacteria have a quorum-sensing system and produce N-acyl-L-homoserine lactone (AHL) that they use them as a quorum-sensing signal molecule. Pantoea ananatis is reported as a common colonist of wheat heads at ripening and causes center rot of onion. In this study, we demonstrated that P. ananatis SK-1 produced two AHLs, N-hexanoyl-L-homoserine lactone (C6-HSL) and N-(3-oxohexanoyl)-L-homoserine lactone (3-oxo-C6-HSL). We cloned the AHL-synthase gene (eanI) and AHL-receptor gene (eanR) and revealed that the deduced amino acid sequence of EanI/EanR showed high identity to those of EsaI/EsaR from P. stewartii. EanR repressed the ean box sequence and the addition of AHLs resulted in derepression of ean box. Inactivation of the chromosomal eanI gene in SK-1 caused disruption of exopolysaccharide (EPS) biosynthesis, biofilm formation, and infection of onion leaves, which were recovered by adding exogenous 3-oxo-C6-HSL. These results demonstrated that the quorum-sensing system involved the biosynthesis of EPS, biofiim formation, and infection of onion leaves in P. ananatis SK-1.

Published
2007

16. Inhibition of Quorum sensing in Serratia marcescens AS-1 by synthetic analogs of N-Acylhomoserine lactone

Author

Morohoshi, Tomohiro, Shiono, Toshitaka, Takidouchi, Kiyomi, Kato, Masashi, Kato, Norihiro, Kato, Junichi, and Ikeda, Tsukasa

Subjects
Quorum sensing -- Research, Nocardia corallina -- Research, Nocardia corallina -- Physiological aspects, Biological sciences
Abstract

A series of N-acyl cyclopentylamides is synthesized with acyl chain lengths ranging from 4 to 12 and their inhibitory effects on prodigiosin production in AS-1are estimated. It is observed that N-nonanoyl-cyclopentylamide ([C.sub.9]-CPA) is an effective quorum-sensing inhibitor for Serratia marcescens AS-1.

Published
2007

19. Accumulation of inorganic polyphosphate in phoU mutants Escherichia coli and Synechocystis sp. strain PCC6803

Author

Morohoshi, Tomohiro, Maruo, Tatsuya, Shirai, Yoko, Kato, Junichi, Ikeda, Tsukasa, Takiguchi, Noboru, Ohtake, Hisao, and Kuroda, Akio

Subjects
Microbiological research -- Analysis, Microbiology -- Environmental aspects, Escherichia coli -- Genetic aspects, Phosphates -- Genetic aspects, Polymers -- Genetic aspects, Gene mutations -- Physiological aspects, Inorganic compounds -- Physiological aspects, Biological sciences
Abstract

Research has been conducted on Synechocystis sp. strain PCC6803. The insertional phoU gene inactivation in this strain and the intracellular polyphosphate level increase in the mutant are discussed.

Published
2002

24. Involvement of an extracellular protease in algicidal activity of the marine bacterium Pseudoalteromonas sp strain A28

Author

Lee, Sun-Og, Kato, Junichi, Takiguchi, Noboru, Kuroda, Akio, Ikeda, Tsukasa, Mitsutani, Atsushi, and Ohtake, Hisao

Subjects
Marine bacteria -- Physiological aspects, Diatoms -- Physiological aspects, Proteases -- Physiological aspects, Cell death -- Physiological aspects, Biological sciences
Abstract

Research reveal that extracellular product of the marine bacterium Pseudoalteromonas sp strain A28 possesses algicidal activity mediated by protease. Studies with the purified enzyme and protease minus mutants show that extracellularly produced serine protease is responsible for the algicidal activity against the diatom.

Published
2000

25. Identification and characterization of two chemotactic transducers for inorganic phosphate in Pseudomonas aeruginosa

Author

Wu, Hong, Kato, Junichi, Kuroda, Akio, Ikeda, Tsukasa, Takiguchi, Noboru, and Ohtake, Hisao

Subjects
Bacteriology -- Research, Phosphates -- Research, Pseudomonas aeruginosa -- Research, Chemoreceptors -- Research, Biological sciences
Abstract

Research has been conducted on the Pseudomonas aeruginosa. Results indicate that P. aeruginosa possesses two chemoreceptors for inorganic phosphate.

Published
2000

26. Physical map location of the multicopy genes coding for ammonia monooxygenase and hydroxylamine oxidoreductase in the ammonia-oxidizing bacterium Nitrosomonas sp. strain ENI-11

Author

HIrota, Ryuichi, Yamagata, Akira, Kato, Junichi, Kuroda, Akio, Ikeda, Tsukasa, Takiguchi, Noboru, and Ohtake, Hisao

Subjects
Bacteriology -- Research, Genetic translation -- Analysis, Ammonia -- Analysis, Oxidation-reduction reaction -- Analysis, Chromosomes -- Analysis, Electrophoresis -- Analysis, Biological sciences
Abstract

Research has been conducted on the PmeI digests of Nitrosomonas sp. strain ENI-11 chromosome. The results of the PmeI pulsed-field electrophoresis are discussed.

Published
2000

27. Fluorescent cyclodextrins responsive to molecules and metal ions. Fluorescence properties and inclusion phenomena of Nalpha-dansyl-L-lysine-beta-cyclodextrin and monensin-incorporated Nalpha-dansyl-L-lysine-beta-cyclodextrin

Author

Ueno, Akihiko, Ikeda, Akira, Ikeda, Hiroshi, Ikeda, Tsukasa, and Toda, Fujio

Subjects
Cyclodextrins -- Analysis, Monensin -- Analysis, Chemistry, Organic -- Research, Biological sciences, Chemistry
Abstract

The synthesis, fluorescence spectra, lifetimes and guest-dependent properties of monensin-incorporated Nalpha-dansyl-L-lysine-beta-cyclodextrin (CD) have been studied by using Nalpha-dansyl-L-lysine-beta-CD and Nepsilon-benzyloxycarbonyl-Nalpha-dansyl-L-lysine-beta-CD as the reference compounds. Results indicate that monensin can change the environment around the cyclodextrin cavity by forming a ring-like conformation with a sodium ion in the center.

Published
1999

31. Fluorescent cyclodextrins for molecule sensing: fluorescent properties, NMR characterization, and inclusion phenomena of N-dansylleucine-modified cyclodextrins

Author

Ikeda, Hiroshi, Nakamura, Michiei, Ise, Nobuyuki, Oguma, Naomi, Nakamura, Asao, Ikeda, Tsukasa, Toda, Fujio, and Ueno, Akihiko

Subjects
Cyclodextrins -- Research, Molecular spectroscopy -- Research, Chemistry
Abstract

The synthesis and characterization of fluorophore-amino acid-cyclodextrin (CD) triads as molecular sensors were carried out. The fluorescent CDs, which displayed variable fluorescence and absorption intensities upon addition of a guest molecule, were N-dansyl-L-leucine-modified and N-dansyl-D-leucine-modified beta-CD, and N-dansyl-L-leucine-modified and N-dansyl-D-leucine-modified gamma-CD.

Published
1996

35. Inclusion of azulene and alcohol by beta-cyclodextrin in aqueous solutions

Author

Hamai, Sanyo, Ikeda, Tsukasa, Nakamura, Asao, Ikeda, Hiroshi, Ueno, Akihiko, and Toda, Fujio

Subjects
Cyclodextrins -- Research, Circular dichroism -- Methods, Nuclear magnetic resonance spectroscopy -- Methods, Chemistry
Abstract

A ternary inclusion complex of beta-cyclodextrin (beta-CD) with alcohol and azulene is studied by induced circular dichroism (ICD) and 1H NMR techniques. The complex consists of two beta-CD's, two alcohols and one azulene. The fluorescence spectra of azulene aqueous solution with varying concentration of beta-CD and the ICD spectra with beta-CD and with both beta-CD and 1-propanol are presented.

Published
1992

43. Evaluation of Intraspecies Interactions in Biofilm Formation by Methylobacterium Species Isolated from Pink-Pigmented Household Biofilms

Author

Xu, Fang-Fang, Morohoshi, Tomohiro, Wang, Wen-Zhao, Yamaguchi, Yuka, Liang, Yan, and Ikeda, Tsukasa

Subjects
Family Characteristics, Microscopy, Confocal, Molecular Sequence Data, pink biofilm, Articles, Pigments, Biological, Sequence Analysis, DNA, biochemical phenomena, metabolism, and nutrition, DNA, Ribosomal, Methylobacterium, Biofilms, Environmental Microbiology, RNA, Ribosomal, 18S, bacteria, Cluster Analysis, Humans, Microbial Interactions, household biofilm, intraspecies interaction, Phylogeny
Abstract

Concern regarding household biofilms has grown due to their widespread existence and potential to threaten human health by serving as pathogen reservoirs. Previous studies identified Methylobacterium as one of the dominant genera found in household biofilms. In the present study, we examined the mechanisms underlying biofilm formation by using the bacterial consortium found in household pink slime. A clone library analysis revealed that Methylobacterium was the predominant genus in household pink slime. In addition, 16 out of 21 pink-pigmented bacterial isolates were assigned to the genus Methylobacterium. Although all of the Methylobacterium isolates formed low-level biofilms, the amount of the biofilms formed by Methylobacterium sp. P-1M and P-18S was significantly increased by co-culturing with other Methylobacterium strains that belonged to a specific phylogenetic group. The single-species biofilm was easily washed from the glass surface, whereas the dual-species biofilm strongly adhered after washing. A confocal laser scanning microscopy analysis showed that the dual-species biofilms were significantly thicker and tighter than the single-species biofilms.

Published
2014

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