Publications by authors named "Yukihiro Tamaki"

Vaccines against Shiga toxin (Stx)-producing Escherichia coli (STEC) have not yet been developed. Two immunologically distinct serotypes of Stx (Stx1 and Stx2) are the main virulence factors of STEC. Thus, blocking their B subunits (StxB) from binding to the cell surface receptor globotriaosylceramide (Gb3) efficiently prevents the action of these toxins.

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Article Synopsis
  • Pvs25, a protein from Plasmodium vivax, is being studied for use in a malaria transmission-blocking vaccine, but its expression is challenging due to its complex structure.
  • Researchers successfully expressed Pvs25 in silkworms, producing it in a form that did not require extensive purification, unlike other systems.
  • The Pvs25 protein from silkworms induced strong immune responses in mice and accurately targeted malaria parasites, highlighting its potential as a vaccine candidate.
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Egg-drop syndrome (EDS) virus is an avian adenovirus that causes a sudden drop in egg production and in the quality of the eggs when it infects chickens, leading to substantial economic losses in the poultry industry. Inactivated EDS vaccines produced in embryonated duck eggs or cell culture systems are available for the prophylaxis of EDS. However, recombinant subunit vaccines that are efficacious and inexpensive are a desirable alternative.

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The cholera toxin B subunit (CTB) is secreted in its pentameric form from Escherichia coli if its leader peptide is replaced with one of E. coli origin. However, the secretion of the pentamer is generally severely impaired when the molecule is mutated or fused to a foreign peptide.

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A novel α-glucan substituted rare 6-deoxy-D-altropyranose was isolated from edible fruiting bodies of a mushroom (Lactarius lividatus) grown in Okinawa, Japan. The polysaccharide consists of D-glucose, D-galactose and 6-deoxy-D-altrose in a molar ratio of 3.0:1.

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6-Deoxy-L-altrose is well known as a constituent sugar moiety of lipopolysaccharides in Gram-negative bacteria. However, its isomer, 6-deoxy-D-altrose, is little known. Identification of 6-deoxy-D-altrose isolated from a polysaccharide extracted from an edible mushroom (Lactarius lividatus), its comparison with chemically synthesized 6-deoxy-D-altrose using (1)H and (13)C NMR including COSY, HMQC spectroscopy, and investigation of its specific optical rotation were all conducted in this study.

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The flow behavior, dynamic viscoelasticity, and optical rotation of aqueous solutions of wheat amylose were measured using a rheogoniometer and a polarimeter. The amylose solutions, at 25 °C, showed shear-thinning behavior at a concentration of 1.2%, but plastic behavior at 1.

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Analysis of the chemical components of lignocellulosic biomass is essential to understanding its potential for utilization. Mid-infrared spectroscopy and partial least-squares regression were used for rapid measurement of the carbohydrate (total glycans; glucan; xylan; galactan; arabinan; mannan), ash, and extractives content of triticale and wheat straws. Calibration models for total glycans, glucan, and extractives showed good and excellent predictive performance on the basis of slope, r², RPD, and R/SEP criteria.

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The effects of temperature (116 °C, 150 °C, and 183 °C) and flow rate (66, 150, and 234 mL/min) on the fractionation of triticale straw into different products was determined using a flow-through pressurized low polarity water reactor. The greatest concentration of biomass was hydrolyzed and extracted in the first two of eight 600 mL fractions (1.2 L), after which dry matter yield decreased.

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To determine lignin content in triticale and wheat straws, calibration models were built using Fourier transform mid-infrared spectroscopy combined with partial least-squares regression. The best model for triticale and wheat straws was built using averaged spectra with raw spectrum in spectrum format and constant in path length as spectral pretreatments. The values of r(2), root-mean-square error of prediction (RMSEP), and residual predictive deviation (RPD) for the triticale straw model were 0.

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We investigated macrophage activation by fucoidan from Laminaria angustata var. longissima in a murine macrophage cell line, RAW 264.7.

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A galactomannan isolated from seeds of Delonix regia was investigated. The specific rotation of the galactomannan was +15 degrees at 25 degrees C. The molecular mass of the galactomannnan was estimated to be 2.

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Lignocellulose is a promising starting material for bioproducts, ranging from biofuels to specialty chemicals; however, lignocellulose is resistant to enzymatic degradation. Overcoming this resistance is therefore an important priority for the development of the lignocellulosic biorefinery concept. In this work, 1-ethyl-3-methylimidazolium acetate ([emim]Ac) was selected from six ionic liquid candidates for the extraction of lignin from triticale and wheat straw and flax shives.

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A pectin was extracted from the peel of Citrus tankan with a yield of 2.75%. The uronic acid content was 80.

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