Publications by authors named "Hirotaka Tajima"

Streptolysin O (SLO), a bacterial toxin produced by common hemolytic streptococci, including and resident microbiota, may be associated with inflammation in the cardiovascular system. We previously reported that short-term treatment with SLO at relatively high concentrations (10-1000 ng/mL) diminished acetylcholine-induced, endothelial-dependent relaxation in a concentration-dependent manner. However, the vascular function effects of long-term exposure to SLO at lower concentrations are poorly understood.

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Uropathogenic (UPEC) is a major causative agent of urinary tract infections. The bacteria internalize into the uroepithelial cells, where aggregate and form microcolonies. UPEC fimbriae and flagella are important for the formation of microcolonies in uroepithelial cells.

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Article Synopsis
  • Some bacteria can change a harmful chemical called tellurate into a safer form, but scientists didn't know which genes helped with this process.
  • In a study, researchers looked at the genes in E. coli and found that taking away 29 specific genes made it harder for the bacteria to reduce tellurate.
  • They discovered that the ynfEF genes were mainly responsible for this process and also found that certain other genes played important roles in helping E. coli make necessary enzymes.
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The grape skins after pressing the juice are a major problem for winery. However, because it contains a large amount of polyphenols, development of effective usages are expected to construct sustainable waste use. In this study, we examined whether grape skin extract is effective for recovery of DNA damage caused by UV irradiation.

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Cellulose synthase is the enzyme that produces cellulose in the living organisms like plant, and has two functions: polymerizing glucose residues (polymerization) and assembling these polymerized molecules into a crystalline microfibril with a "cellulose I" crystallographic structure (crystallization). Many studies, however, have shown that an in vitro reaction of cellulose synthase produces aggregates of a non-native crystallographic structure "cellulose II", despite the remaining polymerizing activity. This is partial denaturation or loss of crystallization function in cellulose synthase, which needs to be resolved to reconstitute its native activity.

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This paper presents a method for single cell stiffness measurement based on a nano-needle and nanomanipulation. The nano-needle with a buffering beam was fabricated from an atomic force microscope cantilever by the focused ion beam etching technique. Wild type yeast cells (W303) were prepared and placed on the sample stage inside an environmental scanning electron microscope (ESEM) chamber.

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Scaffolds serving as artificial extracellular matrixes (ECMs) play a pivotal role in the process of tissue regeneration by providing optimal cellular environments for penetration, ingrowth, and vascularization. Stacks of sheet-like scaffold can be engineered to become artificial ECMs, suggesting a great potential for achieving complex 3-D tissue regeneration to support cell survival and growth. In this study, we proposed and investigated a combined particulate leaching of magnetic sugar particles (MSPs) and salt particles for the development of a sheet-like scaffold.

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The chemotaxis of Vibrio cholerae, the causative agent of cholera, has been implicated in pathogenicity. The bacterium has more than 40 genes for methyl-accepting chemotaxis protein (MCP)-like proteins (MLPs). In this study, we found that glycine and at least 18 L-amino acids, including serine, arginine, asparagine, and proline, serve as attractants to the classical biotype strain O395N1.

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Escherichia coli has closely related amino acid chemoreceptors with distinct ligand specificity, Tar for l-aspartate and Tsr for l-serine. Crystallography of the ligand-binding domain of Tar identified the residues interacting with aspartate, most of which are conserved in Tsr. However, swapping of the nonconserved residues between Tsr and Tar did not change ligand specificity.

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