Reduction of formaldehyde emission from plywood using composite resin composed of resorcinol–formaldehyde and urea-modified scallop shell nanoparticles

More than 200,000 tons of scallop shells are disposed annually alone in Japan. Nanoparticles derived from scallop shells have the potential to adsorb gaseous formaldehyde; therefore, such discarded shells have now been tested as additive filler in plywood adhesive by mixing high specific surface area, urea-modified shell nanoparticles with a resorcinol–formaldehyde resin. With this procedure, it was found that the emission of formaldehyde from the resulting plywood could be substantially reduced. The urea-modified scallop shell nanoparticles were prepared by two different methods: (1) a dry method where the shells were treated by planetary ball-grinding under ambient conditions—a completely dried powder was obtained after addition of the surface-modifying urea solution; (2) a moist method by treating dry ground shell particles in a wet grinding process with the urea solution, followed by centrifugation to obtain a paste. The specific surface area of the nanoparticles obtained by both treatments was 42 ± 3 m²/g. Measurement of the subsequent formaldehyde emission showed that the addition of the modified scallop shell nanoparticles substantially reduced the formaldehyde emission from plywood. The reduction of the specific mass uptake of urea depends on the nanoparticles which especially was the case when resins containing nanoparticles processed by the moist method were used.     

Differential Expression of Two Cytosolic Ascorbate Peroxidases and Two Superoxide Dismutase Genes in Response to Abiotic Stress in Rice

Superoxide dismutase (SOD) and ascorbate peroxidase (APX) play central roles in the pathway for scavenging reactive oxygen species in plants, thereby contributing to the tolerance against abiotic stress. Here we report the responses of cytosolic SOD (cSOD; sodCc1 and sodCc2) and cytosolic APX (cAPX; OsAPX1 and OsAPX2) genes to oxidative and abiotic stress in rice. RNA blot analyses revealed that methyl viologen treatment caused a more prominent induction of cAPXs compared with cSODs, and hydrogen peroxide t...     

Transmission of <Emphasis Type="Italic">Tomato chlorotic dwarf viroid</Emphasis> by bumblebees (<Emphasis Type="Italic">Bombus ignitus</Emphasis>) in tomato plants

Quantitative PCR revealed that Tomato chlorotic dwarf viroid (TCDVd) was present in substantial amounts in viroid-infected tomato flowers. Healthy tomato plants were arranged in two different glasshouses, and plants were mechanically inoculated with TCDVd. Bumblebees (Bombus ignitus) were then introduced into the glasshouses to reveal whether the viroid was transmitted from infected source plants to neighbouring healthy plants. TCDVd infection was found in neighbouring tomato plants more than 1 month after the introduction of the bees, some of which expressed symptoms, in both glasshouses. Thus, bumblebees transmitted TCDVd from tomato to tomato by pollination activities.     

Biomass yield and accumulations of bioactive compounds in red amaranth (Amaranthus tricolor L.) grown under different colored shade polyethylene in spring season

Biomass yield and accumulations of betacyanin, chlorophyll, total polyphenol, and antioxidant activity were evaluated growing red amaranth (Amaranthus tricolor L.) in spring season under five different shades made of white, blue, green, yellow, and black polyethylene, and non-shaded frame. Temperature and light intensity varied significantly (P < 0.05) under the different colored polyethylene shades, and these differences in microclimate are implicated for the variability in growth and accumulations of bioactive compounds. The highest temperature was obtained under the blue polyethylene shade and the plants achieved highest plant height, stem length and leaf number, fresh and dry matter biomass, betacyanins, total polyphenol, and antioxidant activity. The achieved biomass yield and accumulation of bioactive compounds were almost similar to field grown red amaranth in summer season. Blue polyethylene shade has probably ensured the optimum microclimate for growth and development of red amaranth in the studied growing period. Exceptionally the plants grown under green polyethylene shade accumulated highest chlorophyll. Although non-shaded plants received highest sunlight intensity but gave the poor biomass yield as well as accumulated less bioactive compounds than plants grown under blue polyethylene shade due to low air temperature. Thus, the results indicated that blue polyethylene has potentials to increase the yield with health beneficiary bioactive compounds betacyanins, polyphenol and antioxidant activity during the low temperature regime in spring season.     

Factors that accelerate dimethylamine formation in dark muscle of three gadoid species during frozen storage

We investigated factors that accelerate dimethylamine formation in gadoid dark muscle. The degradation rate of trimethylamine-N-oxide into dimethylamine and formaldehyde during frozen storage was compared between ordinary muscle and dark muscle from walleye pollock, southern blue whiting, and hoki. Dimethylamine was generated faster in dark muscle than in ordinary muscle in each species, and it was produced most abundantly in hoki dark muscle compared with the other two species. We investigated the mechanism that caused dimethylamine to be generated more abundantly in dark muscle during frozen storage, and found that the amount of dark muscle nonheme iron, which catalyzes trimethylamine-N-oxide degradation, was higher than that in ordinary muscle in each species, and hoki dark muscle in particular contained the highest levels of nonheme iron among these three species. Moreover, dark muscle in all three fish species had a higher taurine content (known to accelerate dimethylamine formation) than ordinary muscle. These data suggested two candidate factors, namely nonheme iron and taurine, that may accelerate dimethylamine generation during frozen storage. In addition, gel filtration results suggested that walleye pollock dark muscle contains as yet unidentified low-molecular-weight agents that stably accelerate dimethylamine generation.     

Quantitative analysis of <Emphasis Type="Italic">Ichthyobodo salmonis</Emphasis> an ectoparasitic flagellate infecting juvenile chum salmon <Emphasis Type="Italic">Oncorhynchus keta</Emphasis> in hatcheries

Ichthyobodosis caused by the ectoparasitic flagellate Ichthyobodo salmonis is a significant cause of mortality in juvenile chum salmon Oncorhynchus keta reared in hatcheries of northern Japan. The present study established a real-time quantitative polymerase chain reaction assay (qPCR) of I. salmonis ribosomal DNA (rDNA) using SYBR Green. This assay allows monitoring of parasite infections for the epidemiological study and control of ichthyobodosis in hatcheries. qPCR showed high reproducibility for measurements between 1.0 and 1.0 × 10⁸ rDNA copy/μl. There was a significant positive correlation between the number of parasites and the amount of I. salmonis rDNA. A survey using the qPCR assay indicated that infection by I. salmonis was present in 23 of 87 hatcheries; parasite loads were estimated to be between 50 and 750 parasites/g juvenile body weight. These results demonstrate that our qPCR assay enables the surveying of juvenile chum salmon reared in hatcheries for infection by I. salmonis.     

Prevalence of Shiga toxin-producing Escherichia coli in Yezo sika deer (Cervus nippon yesoensis) in the Tokachi sub-prefecture of Hokkaido,Japan

In food hygiene, the surveillance of foodborne pathogens in wild animals is indispensable because we cannot control hygienic status of them. Yezo sika deer (Cervus nippon yesoensis), which are found only on the island of Hokkaido, Japan, are the most common game animal in the country. In this study, we analyzed the incidence of Shiga toxin-producing Escherichia coli (STEC) in Yezo sika deer hunted in the Tokachi sub-prefecture, which is one of the densest zones for the sub-species. Real-time polymerase chain reaction testing detected STEC in 18.3% of fecal samples (59/323) collected from deer hunted between 2016 and 2017, whereas no Shigella and Salmonella markers were detected. No correlation was found between STEC detection from fecal samples and characteristics of carcasses, such as hunting area, age, and fascioliasis. From 59 STEC-positive fecal samples, we isolated 37 STEC strains, including 34 O- and H-genotyped strains, in which 16 different serogroups were detected. Genetic analysis revealed that our isolates included various stx gene types (stx1⁺/stx2⁻, stx1⁺/stx2⁺, and stx1⁻/stx2⁺) and carried eae. This study demonstrated that STEC strains with various features colonized the Yezo sika deer, similar to other subspecies of sika deer. We conclude that continuous surveillance activity is important to monitor the suitability of game animals as a food source and to assess the validity of the food safety management system for game meat production.