Roles of raccoons in the transmission cycle of severe fever with thrombocytopenia syndrome virus

The present study investigated severe fever with thrombocytopenia syndrome virus (SFTSV) infection in raccoons in Wakayama Prefecture from 2007 to 2019. To perform surveillance, an enzyme-linked immunosorbent assay (ELISA) was established, and the sensitivity and specificity of the ELISA were 100% in comparison with a 50% focus-reduction neutralization assay. Using the established ELISA, we performed serosurveillance of SFTSV infection in 2,299 raccoons in Tanabe region, Wakayama Prefecture from 2007 to 2019. The first anti-SFTSV-positive raccoon was captured in October 2009. The seroprevalence of SFTSV infection was <10% between April 2009 and March 2013, 23.9% between April 2013 and March 2014, 37.5% between April, 2014 and March 2015, and over 50% from April 2015. Next, we performed detection of SFTSV genes in sera of raccoons captured in Wakayama Prefecture after April 2013. The results indicated that 2.4% of raccoons were positive for SFTSV genes and that the frequency of SFTSV infection among raccoons between January and March (0.7%) was lower than that between April and June (3.4%). In addition, virus genes were detected from many specimens, including sera and feces of two raccoons, and viral antigens were detected in lymphoid cells in lymphoid follicles in the colon by immunohistochemical staining. In conclusion, SFTSV had recently invaded the area and had rapidly spread among wild animals. The first patient in this area was reported in June 2014, indicating that raccoons are good sentinels for assessing the risk of SFTSV in humans.     

Evaluation of Starch Properties of Wheats Used for Chinese Yellow-Alkaline Noodles in Japan

The objective of the present research was to assess the functional properties of the starches isolated from Australian prime hard wheat (PH) and hard red winter wheat (HRW) in the United States. These wheats are favorably used in Japan for the production of Chinese yellow-alkaline noodles (YAN). Starches isolated from PH showed higher amylose content than those of noodle wheat but lower than bread wheat. Analysis of swelling power showed that PH starch had lower values than noodle wheat starches but higher values than bread wheat starches. By contrast, HRW starch showed relatively higher amylose content and lower swelling power. There were large differences in the starch pasting properties between PH and HRW. High-performance size-exclusion chromatography studies on the components leached from the starch (80°C, 20 min) showed that PH starch had a somewhat characteristic leaching profile. Its peak ratio of high molecular weight region to low molecular weight region was greater than that of HRW starch. PH starch also characterized by having lower endothermal enthalpy (ΔH) in amylose-lipid transition. The eating quality assessment for YAN revealed that PH had more elastic texture than HRW. Additional reconstitution studies showed that these quality differences could be attributable to its starch properties.     

Identification of Disulfide Proteins in the Salt Soluble Fraction of Rice (Oryza sativa) Seed

Evidence has been accumulating to suggest that disulfide bonding is one of the key causes of allergenicity. Recently we developed the “disulfide proteome”, a technique for the comprehensive analysis of disulfide bonding of proteins. We applied this new technique to the rice seed's salt‐soluble fraction, which has long been known to be allergenic. Most proteins in the fraction, including α‐amylase/trypsin inhibsitor, α‐ globulin, and glutelin fragments, have formed intramolecular disulfide bonds. Also, unknown proteins, including one sharing similarities with known allergens, had disulfide bonds, from which we can infer possible allergenicity. This is a preliminary study to screen allergens from the basis of disulfide bonding.