Genotypic change of porcine circovirus type 2 on Japanese pig farms as revealed by restriction fragment length polymorphism analysis

Porcine circovirus type 2 (PCV2) has been recognized as the causal agent of postweaning multisystemic wasting syndrome and can be divided into two major genotypic groups. We developed a method of restriction fragment length polymorphism (RFLP) analysis of PCV2 open reading frame 2 for easy discrimination between the two major groups. Genotyping of PCV2 isolates from 10 Japanese commercial pig farms was performed, and the analysis revealed that both PCV2 groups and at least five RFLP types of PCV2 are prevalent in Japan. On two farms, the genotypes of the PCV2 isolates in the spring of 2007 were different from those in the autumn of 2006. One genotype may have become dominant within only six months on these farms.     

Winter longitudinal variation in the body size of larval fishes in the Seto Inland Sea,Japan

This study revealed the spatial variation in abundance and body size of larval fishes in the Seto Inland Sea, Japan, in January 2014 and 2015. Fish larvae were collected by a 1.3-m-diameter ring net towed at the surface and at 10-m depth at 21 stations. The most dominant species was the sandlance Ammodytes japonicus, constituting 82% of total larval fish caught. The body size of A. japonicus was greater [ca. 9 mm total length (TL) in 2014] in eastern areas than in western areas (ca. 5 mm TL in 2014). This trend was also observed in rockfishes (Sebastiscus marmoratus and Sebastes inermis species complex), suggesting a common phenomenon in this region. Because the water temperature was lower in eastern areas, it is likely that the longitudinal differences in larval body size are attributable to earlier spawning in eastern areas caused by different temperature conditions.     

Quality evaluation of different types of non-fish meal diets for yellowtail

SUMMARY: Two feeding experiments were conducted to evaluate the feed quality of non-fish meal diets having the same protein ingredient composition but prepared as different types, and to determine the supplemental effect of crystalline essential amino acids (EAA) on feed utilization by young yellowtail, Seriola quinqueradiata . Non-fish meal diets formulated with soy protein concentrate, defatted soybean meal, corn gluten meal, meat meal, and krill meal were prepared as either soft dry pellets (SDP) or extruded pellets (EP) by using a large- or a small-sized twin screw extruder under different preparation conditions; or as a single moist pellet (SMP), each with and without EAA mixtures. Commercial yellowtail SDP was used as the control diet. Fish weighing 134 g and 237 g on average were reared with the experimental diets, for 93 (net cages) and 44 (aquariums) days, respectively. The fish fed both the control and test diets were found to have a good appetite. Growth rate and feed gain ratio were highest in the control diet group. The physiological condition of fish fed the control diet was evaluated as superior compared to those on the non-fish meal diets. Among the non-fish meal diet groups, the best performances were obtained for fish fed the SDP type diet with EAA supplement, and performance parameters excelled in the order of SDP, EP and SMP both among the diets with and without supplemental EAA. This suggests that the nutritional quality of non-fish meal diet was affected by the diet preparation method. It also indicates that supplementation of EAA could improve the quality of non-fish meal diets, irrespective of the diet type, probably as a result from the enhancement of feed protein utilization.     

Depletion of naturally recruited wild Japanese eels in Okayama,Japan, revealed by otolith stable isotope ratios and abundance indices

To investigate the population dynamics of naturally recruited wild Japanese eels, fisheries data of wild individuals in Okayama Prefecture were investigated as a case study. Wild and stocked eels were discriminated using a recently developed method based on otolith stable isotopes. Of the 161 eels captured in freshwater areas where eels had been stocked, 98.1% were discriminated as stocked. In contrast, 82.8% of 128 eels captured in coastal areas where eels are not stocked were discriminated as wild. There was a significant decrease in longline and set-net catch per unit effort between 2003 and 2016 in the coastal areas where most eels were discriminated as wild, indicating ongoing depletion of wild Japanese eels in these waters.     

Effect of moisture content on the longitudinal tensile creep behavior of wood

In our previous report, we investigated the effect of the microfibril angle (MFA) in the middle layer of the secondary wall (S₂) on the longitudinal creep behavior of a thin homogeneous earlywood specimen sugi. In the present study, we investigated the role of moisture on the tensile creep behavior of wood. We discuss the creep behavior of the wood cell wall from the viewpoint of the composite structure of the cell wall and the properties of the constituent materials. A microtomed thin specimen of earlywood of sugi (Cryptomeria japonica D.Don) was used for the longitudinal tensile creep test. Creep tests were conducted at three moisture stages (oven-dry, air-dry, fiber saturation point) over a broad range of MFA. Results showed that the longitudinal tensile creep behavior was highly dependent on both the moisture content and the MFA. With a small MFA, the variation in the creep function among the three moisture states was very small. For a large MFA, the variation in the creep function was larger. At low moisture contents, the magnitude of the creep function was very small, while at high moisture content, it was very large except for the case of specimens with very small MFA. Those results show that the longitudinal tensile creep behavior was directly affected by the fine composite structure and the internal properties of the cell wall constituents.     

Biomass Cycling and Soil Properties in an Agroforestry-based Plantation System of kayu putih (Melaleuca leucadendron LINN) in East Java, Indonesia

We investigated age-related changes in biomass cycling and soil properties in a kayu putih (Melaleuca leucadendron LINN, Myrtaceae) with improved shifting cultivation system in East Java, Indonesia, to design better management plans for sustainable kayu putih oil production and crop yield. Harvested biomass of kayu putih increased markedly from 7- to 15-year-old stands, but did not increase further in older stands averaging 2.41 Mg ha⁻¹ yr⁻¹. Kayu putih contributed 1.9–31.0% of total biomass production. Cassava (Manihot esculenta Crantz) tuber was the largest component of biomass cycling. Harvested biomass of cassava decreased with increasing stand age and there was a trade-off between above- and below-ground biomass productions. Harvested biomass of maize (Zea mays L.) grain was constant throughout stand growth, whereas returned biomass fluctuated. With increasing stand age, soil organic matter (SOM) accumulated in soil indicating that returned biomass was decomposing slowly. Content of primary nutrients did not change with stand age. The contribution of cassava to harvested biomass was considerably larger than that of kayu putih. For this reason, selection of cassava as a single companion crop may not be suitable for sustaining kayu putih oil production. Maize may be a good companion crop for kayu putih because it produces a constant grain yield throughout stand growth and its contribution to harvested biomass is comparable to that of kayu putih. In addition, maize is shallow-rooted and causes less below-ground competition with deep-rooted kayu putih trees.     

Development of highly sprouting tolerant wheat germplasm with reduced germination at low temperature

The development of sprouting tolerant spring and winter wheat varieties that retain dormancy in cool, wet conditions is a long-term objective in Hokkaido, Japan. A highly tolerant spring dwarf line, “OS21-5”, derived from “Tordo” × “Zenkoji”, was used to develop transgressive spring, “OS38” and “OS74”; and winter, “OW77”, “OW104” and “OW93” wheats. More recently, winter lines with improved agronomic performance, though still deficient in quality and scab resistance, have been identified. In general, germination percentage of mature grain at 10 ^°C was closely related to the mean temperature experienced during the 5 days prior to maturity (dough–yellow ripening stage) and to the capacity to maintain a high amylograph paste viscosity. Dormancy at 10 ^°C appeared to be determined by a combination of genotype and variation in sensitivity to temperature during the later stages of ripening. Genotypes such as “OS38” and ‘OWl04’ were both highly tolerant to germination at 10 ^°C and insensitive to temperature during ripening. By comparison, most of the other cultivars showed a similar, intermediate sensitivity to ripening temperature, and dormancy decreased as ripening temperature increased. Dormancy of‘RL4137’ at maturity, and to a lesser extent ‘Gifukomugi’ and ‘KKI354’, was very sensitive to ripening temperature and useful levels of dormancy only developed under cool ripening temperatures, mean temperature < 18–20 ^°C.     

Requirement for signal peptide cleavage of Escherichia coli prolipoprotein

Oligonucleotide-directed site-specific mutagenesis was applied to alter the cleavage site in the signal peptide of the major outer membrane lipoprotein of Escherichia coli. Replacing the glycine residue at the cleavage site with an alanine residue did not affect the processing of the signal peptide. However, when the same cleavage site was constructed by the deletion of the glycine residue, the signal peptide was no longer cleaved. These results indicate that stringent structural integrity at the cleavage site in the lipoprotein signal sequence is required for correct processing of prolipoprotein.     

Effect of furnish type and high-density raw material from mill residues on properties of particleboard panels

The purposes of this study were to examine the use of furniture mill residues containing high-density raw materials in particleboard production and to evaluate the effect of mixing several types of furnish on board performance. Wood wastes collected from the furniture industry in Japan containing matoa (Pometia pinnata), Douglas-fir (Pseudotsuga menziesii), and sugi (Cryptomeria japonica) with different particle shapes were prepared as raw materials for use in the manufacture of experimental particleboards. Seven board types and three mixed boards were manufactured with three replications. Methylene diphenyl diisocyanate (MDI) resin was applied at 6 % content in mat preparation. The pressing conditions were temperature of 180 °C, initial pressure of 3 MPa, and pressing time of 5 min. The target density was 0.72 g/cm³. This study showed that matoa particleboard had properties suitable for use in interior applications, although its properties were considered inferior compared with other particleboards. Improvement of matoa particleboard could be achieved by mixing with higher quality wood particles such as those from sugi or Douglas-fir. The furnish type used in this study affected board performance. All residues from furniture mills have the potential to be used for particleboard production, even when they contain different furnish types and wood species.