Publications by authors named "Minoru Takeda"

Aims: Hydrogels have applications as food additives and cosmetics, as well as medical applications such as the drug delivery and scaffolding materials for cells. There is high demand for new hydrogels that can facilitate technological innovation. Here, we report a galactomannan-like gelling agent (hydrogel) produced by the sheath-forming bacterium Sphaerotilus hippei.

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Aims: Glucosaminoglucan (β-1,4-linked glucose and glucosamine) produced by a mixotrophic sulfur-oxidizing bacterium, Thiothrix nivea, is a useful cellulose-aminating agent. Lithotrophic and mixotrophic glucosaminoglucan production were examined using fed-batch techniques.

Methods And Results: A jar fermenter was used for the fed-batch cultivation.

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A microaerophilic Gram-stain-negative bacilliform bacterial strain, FB-5, was isolated from activated sludge in Yokohama, Japan, that exhibited filamentous growth and formed a microtube (sheath). Cells were motile using a single polar flagellum. The optimum growth temperature and pH were 30 °C and 7.

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Aims: Enzymatic degradation of β-1,4-linked glucose and glucosamine (glucosaminoglucan, GG), which is prepared from Thiothrix nivea and can act as a cellulose-aminating agent with a strong affinity to cellulose, was attempted.

Methods And Results: A chitosanase-secreting fungal strain was isolated as a GG-degrading microbe. GG was found to be degraded by not only chitosanases but also cellulases.

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Genetic strategies such as gene disruption and fluorescent protein tagging largely contribute to understanding the molecular mechanisms of biological functions in bacteria. However, the methods for gene replacement remain underdeveloped for the filamentous bacteriaSP-6. Their cell chains are encased in sheath composed of entangled nanofibrils, which may prevent the conjugation for gene transfer.

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Article Synopsis
  • - The bacterium Leptothrix cholodnii forms cell chains with protective sheaths made of woven nanofibrils, primarily consisting of glycoconjugate repeats, and relies on specific glycosyltransferases (GTs) for their formation, with LthA being the only one identified so far.
  • - A study discovered a new GT, designated LthB, that plays a crucial role in nanofibril biosynthesis, as deletion of this protein resulted in sheathless cell chains, indicating that sheaths are not essential for the elongation of these chains.
  • - The research suggests that the cooperation between LthA and LthB in glycoconjugate biosynthesis is regulated by different signals
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Haliscomenobacter hydrossis is a filamentous bacterium common in activated sludge. The bacterium was found to utilize hyaluronic acid, and hyaluronate lyase activity was detected in its culture. However, no hyaluronate lyase gene was found in the genome, suggesting the bacterium secretes a novel hyaluronate lyase.

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The bacterium Leptothrix cholodnii generates filaments encased in a sheath comprised of woven nanofibrils. In static liquid culture, moves toward the air-liquid interface, where it forms porous pellicles. Observations of aggregation at the interface reveal that clusters consisting of only a few bacteria primarily grow by netting free cells.

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The resistive switching temperature associated with the metal-insulator transition (MIT) of epitaxial VO thin films grown on flexible synthetic mica was modulated by bending stress. The resistive switching temperature of polycrystalline VO and VO thin films, initially grown on synthetic mica without a buffer layer, was observed not to shift with bending stress. By inserting a SnO buffer layer, epitaxial growth of the VO (010) thin film was achieved, and the MIT temperature was found to vary with the bending stress.

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Aims: This study aimed to unveil perrhenate sorption properties of the filamentous sheaths formed by Sphaerotilus montanus, Sphaerotilus natans and Thiothrix fructosivorans.

Methods And Results: The adsorptions of perrhenate on lyophilizates of the above-mentioned filamentous sheaths were analysed by ICP, IR, XPS and EDX. The capacity reached 82 mg per g-adsorbent, when using S.

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Sphaerotilus natans is a filamentous sheath-forming bacterium commonly found in activated sludge. Its sheath is assembled from a thiolic glycoconjugate called thiopeptidoglycan. S.

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β-1,4-glucosaminoglucan (GG) was prepared from the sheath of a sulfur-oxidizing bacterium . Recently, GG was found to be adsorbed by cellulose (paper) and is therefore potentially applicable as an aminating agent for cellulose. We attempted to increase the yield of GG using a fed-batch cultivation method.

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This study reveals that the abundance of the filament Kouleothrix (Eikelboom type 1851) correlated positively with poor settleability of activated sludge biomass in a Japanese full-scale nutrient removal wastewater treatment plant sampled over a one-year period. 16S rRNA amplicon sequence data confirmed that Kouleothrix was the dominant filament in the plant, with a relative abundance of 3.06% positively correlated with sludge volume index (SVI) (R = 0.

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Prolific heterotrophic biofilm growth is a common occurrence in airport receiving streams containing deicers and anti-icers, which are composed of low-molecular weight organic compounds. This study investigated biofilm spatiotemporal patterns and responses to concurrent and antecedent (i.e.

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Recently, a project was initiated in Japan to transport a large amount of liquid hydrogen (LH₂) from Australia to Japan by sea. It is important to understand the sloshing and boil-off that are likely to occur inside an LH₂ tank during marine transportation by ship, but such characteristics are yet to be experimentally clarified. To do so, we combined the liquid level detected by five 500 mm long external-heating-type magnesium diboride (MgB₂) level sensors with synchronous measurements of temperature, pressure, ship motion, and acceleration during a zigzag maneuver.

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Thiothrix nivea is a filamentous sulfur-oxidizing bacterium common in activated sludge and its filament is covered with a polysaccharide layer called sheath. In this study, we found that T. nivea aggregates under acidic conditions.

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Thiothrix nivea is a filamentous sulfur-oxidizing bacterium commonly found in activated sludge. The filament of this bacterium is covered with a sheath. The sheath is an assemblage of macromolecular glucosaminoglucan (GG), [4)-β-d-GlcN-(1 → 4)-β-d-Glc-(1 → ], modified with an unidentified deoxy-sugar at position 3 of Glc.

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Thiothrix strains are filamentous sulfur-oxidizing bacteria common in activated sludge. Some of the members, including Thiothrix nivea and T. fructosivorans, are known to form a microtubular sheath that covers a line of cells.

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A soil bacterium, Mycobacterium sp. B-009, is able to grow on racemic 1,2-propanediol (PD). The strain was revealed to oxidize 3-methyl-1,5-pentanediol (MPD) to 5-hydroxy-3-methyl-pentanoic acid (HMPA) during growth on PD.

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Thiothrix fructosivorans forms a microtube (sheath) that encloses a line of cells. This sheath is an assemblage of [→4)-GlcN-(1→4)-Glc-(1→]n with side chains of Rha4N-(1→3)-Fuc(1→ at position 3 of Glc. The sheath-forming polysaccharide (SFP) may have some substitutions but this is not yet confirmed.

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An enzyme capable of reducing acetoin in the presence of NADH was purified from Mycobacterium sp. B-009, a non-clinical bacterial strain of soil origin. The enzyme is a homotetramer and can be classified as a medium-chain alcohol dehydrogenase/reductase based on the molecular weight of the monomer.

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A sheath-forming and sulfur-oxidizing bacterium, Thiothrix fructosivorans, was heterotrophically cultured. The sheath, which is an extracellular microtube, was prepared by selectively removing the cells using lysozyme, sodium dodecyl sulfate, and sodium hydroxide. Solid-state (13)C-nuclear magnetic resonance (NMR) spectrum revealed that the sheath is assembled from a glycan possessing acetyl and methyl groups.

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Sphaerotilus natans is a filamentous sheath-forming bacterium. A method of selective fluorescent-labeling of its sheath using conventional reagents was developed. Terminal expansion of the sheath was confirmed by this method.

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Sphaerotilus natans is a filamentous sheath-forming bacterium, commonly found in bulking activated sludge. The bulky nature of this bacterium is caused by an extracellular polysaccharide (EPS). EPS is a linear acidic polysaccharide with the following chemical structure: [ → 4)-α-D-Glcp-(1 → 2)-β-D-GlcpA-(1 → 2)-α-L-Rhap-(1 → 3)-β-L-Rhap-(1 → ](n).

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Leptothrix cholodnii is a Mn(II)-oxidizing and sheath-forming member of the class β-Proteobacteria. Its sheath is a microtube-like filament that contains a chain of cells. From a chemical perspective, the sheath can be described as a supermolecule composed of a cysteine-rich polymeric glycoconjugate, called thiopeptidoglycan.

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