The goal of this study is to clarify how different aspects of plant function are coordinated developmentally for species of ring‐porous versus diffuse‐porous deciduous trees, comparing the timing of leaf phenology and vessel formation in twigs and stems from an ecophysiological viewpoint. Cylindrical stem cores and twigs were collected at intervals from early spring through summer from five ring‐porous and five diffuse‐porous species in a cool temperate forest, and leaf and vessel formation were observed simultaneously. We found that the first‐formed vessels of the year were lignified in twigs around the time of leaf appearance and at or before full leaf expansion of each tree in both groups of species with flush‐leaves. Vessels in stems were lignified 2 weeks before to 4 weeks after leaf appearance and before or around full leaf expansion of the tree in ring‐porous species. This was significantly earlier than in diffuse‐porous species, in which stem vessel lignification was 2–8 weeks after leaf appearance and at or after full leaf expansion of the tree. The timing of vessel formation in twigs compared to stems was significantly earlier in ring‐porous species than in diffuse‐porous species. Lignification of vessels in stems occurred within 2 weeks of lignification in the twigs of ring‐porous species and 2–8 weeks after lignification in twigs of diffuse‐porous species. These results indicate the order and time‐lag of leaf and vessel formation. Ring‐porous species showed intensive leaf/vessel production, whereas diffuse‐porous species showed less intensive leaf/vessel production.

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Water sampling and filtration of environmental DNA (eDNA) analysis have been performed by several different methods, and each method may yield a different species composition or eDNA concentration. Here, we investigated the eDNA of seawater samples directly collected by SCUBA to compare two widely used filtration methods: open filtration with a glass filter (GF/F) and enclosed filtration (Sterivex). We referred to biomass based on visual observation data collected simultaneously to clarify the difference between organism groups. Water samples were collected at two points in the Sea of Japan in May, September and December 2018. The respective samples were filtered through GF/F and Sterivex for eDNA extraction. We quantified the eDNA concentration of five fish and two cnidarian species by quantitative polymerase chain reaction (qPCR) using species-specific primers/probe sets. A strong correlation of eDNA concentration was obtained between GF/F and Sterivex; the intercepts and slopes of the linear regression lines were slightly different in fish and jellyfish. The amount of eDNA detected using the GF/F filtration method was higher than that detected using Sterivex when the eDNA concentration was high; the opposite trend was observed when the eDNA concentration was relatively low. The concentration of eDNA correlated with visually estimated biomass; eDNA concentration per biomass in jellyfish was approximately 700 times greater than that in fish. We conclude that GF/F provides an advantage in collecting a large amount of eDNA, whereas Sterivex offers superior eDNA sensitivity. Both filtration methods are effective in estimating the spatiotemporal biomass size of target marine species.

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The prevalence of faecal carriage of salmonella in 5393 pigs reared on 218 pig farms located in 31 of 47 prefectures in Japan over the period July 2003 to June 2005 was investigated. We isolated 172 strains belonging to 20 serovars and one untypable Salmonella enterica from 169 pig faecal samples (3.1%) collected from 48 farms (22.0%). The most prevalent type of S. enterica was untypable O4,12:d:- which lacks phase 2 flagellar antigen, representing 29.1% (50/172) of all isolates. Of 26 S. enterica serovar Typhimurium isolates, 16 strains appeared to be definitive phage type 104 (DT104) by polymerase chain reaction.

SUMMARYThe cyclobutane pyrimidine dimer (CPD), which represents a major type of DNA damage induced by ultraviolet-B (UVB) radiation, is a principal cause of UVB-induced growth inhibition in plants. CPD photolyase is the primary enzyme for repairing CPDs and is crucial for determining the sensitivity of Oryza sativa (rice) to UVB radiation. CPD photolyase is widely distributed among species ranging from eubacteria to eukaryotes, and is classified into class I or II based on its primary structure. We previously demonstrated that rice CPD photolyase (OsPHR), which belongs to class II and is encoded by a single-copy gene, is a unique nuclear/ mitochondrial/chloroplast triple-targeting protein; however, the location and nature of the organellar targeting information contained within OsPHR are unknown. Here, the nuclear and mitochondrial targeting signal sequences of OsPHR were identified by systematic deletion analysis. The nuclear and mitochondrial targeting sequences are harbored within residues 487-489 and 391-401 in the C-terminal region of OsPHR (506 amino acid residues), respectively. The mitochondrial targeting signal represents a distinct topogenic sequence that differs structurally and functionally from classical N-terminal pre-sequences, and this region, in addition to its role in localization to the mitochondria, is essential for the proper functioning of the CPD photolyase. Furthermore, the mitochondrial targeting sequence, which is characteristic of class-II CPD photolyases, was acquired before the divergence of class-II CPD photolyases in eukaryotes. These results indicate that rice plants have evolved a CPD photolyase that functions in mitochondria to protect cells from the harmful effects of UVB radiation.

Enterotoxigenic Escherichia coli (ETEC) is a major cause of post-weaning diarrhea (PWD) in pigs and causes significant damage to the swine industry worldwide. In recent years, there has been increased regulation against the use of antibacterial agents in swine due to their health risks. Utilizing experimental models that consistently recapitulate PWD is important for the development of non-antibacterial agents against PWD in pigs. In this study, we established a highly reproducible PWD infection model by examining differences in adhesion of ETEC to the intestinal tissue as well as the association between MUC4 polymorphisms and sensitivity to PWD. Post-weaning diarrhea differences between pig breeds were also examined. The adhesion to enterocytes varied from 104.0 to 106.4 CFU/mL even among the F4 ETEC strains. Experimental infection revealed that PWD can be induced in all MUC4 genotypes after infection with 1010 CFU/pig of highly adherent ETEC, although there were variable sensitivities between the genotypes. Lowly adherent ETEC did not cause PWD as efficiently as did highly adherent ETEC. The incidence of PWD was confirmed for all pigs with the ETEC-susceptible MUC4 genotypes in all of the breeds. These results indicate that high-precision and reproducible experimental infection is possible regardless of pig breeds by controlling factors on the pig-end (MUC4 genotype) and the bacterial-end (adhesion ability).

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