Density estimation of the giant jellyfish Nemopilema nomurai around Japan using an alternative modified detection function for left truncation in a line transect survey

Information on the distribution and bloom scale of the giant jellyfish Nemopilema nomurai is necessary to understand the impact on fisheries. In October 2009, we had an opportunity for visual counting of N. nomurai around Japan from a research/training vessel. To take into account possibly severe missed detection of N. nomurai in the close vicinity of the vessel, detection functions were modified by introducing an additional parameter δ expressing the proportion of detectable N. nomurai within a threshold perpendicular distance. Some covariate effects in the detection process were also investigated. The δ-modified hazard-rate detection function with δ variation parameter of jellyfish body size was chosen as the best-fit one by AIC model selection. The results suggested that a higher proportion (>30 % or more) of N. nomurai were undetected in the vicinity of vessel. The δ-modified model had an advantage of no loss of left-truncated data and provided better estimation of density with the smaller coefficient of variation than the conventional left truncation approach. It is applicable to other line transect surveys, e.g. aerial surveys. High densities of N. nomurai were found in the central part of the Sea of Japan and off Iwate Prefecture.     

Effect of environmental factors and prey species on daytime and nighttime vertical distribution of juvenile walleye pollock in and around Funka Bay

We examined factors affecting the vertical distribution of juvenile walleye pollock during “the second critical period” (i.e. the transition period of prey size) in and around Funka Bay, Hokkaido, Japan. During the day, small juveniles (<30 mm) were distributed mainly in shallow, warm, and low-salinity water within the bay, whereas larger ones (≥30 mm) occurred in deeper, cold and saline water. During the night, the large juveniles migrated to shallower depths. Outside the bay, small- and large-sized juveniles were distributed in water masses of similar physical properties during the daytime, whereas during the nighttime, most of the juveniles moved to shallower depth, and some juveniles dived to deeper water mass. Dietary analysis revealed that large juveniles fed on large copepods (≥0.5 mm in body width) more than small juveniles did. The composition of zooplankton in our survey area showed that large-sized copepods often occurred in deeper saline water. From these results, there is a possibility that juvenile pollock inside and outside Funka Bay occupied different water masses preferable for each feeding advantage.     

Involvement of circadian clock in crowing of red jungle fowls (Gallus gallus)

The rhythmic locomotor behavior of flies and mice provides a phenotype for the identification of clock genes, and the underlying molecular mechanism is well studied. However, interestingly, when examining locomotor rhythm in the wild, several key laboratory‐based assumptions on circadian behavior are not supported in natural conditions. The rooster crowing ‘cock‐a‐doodle‐doo’ is a symbol of the break of dawn in many countries. Previously, we used domestic inbred roosters and showed that the timing of roosters' crowing is regulated by the circadian clock under laboratory conditions. However, it is still unknown whether the regulation of crowing by circadian clock is observed under natural conditions. Therefore, here we used red jungle fowls and first confirmed that similar crowing rhythms with domesticated chickens are observed in red jungle fowls under the laboratory conditions. Red jungle fowls show predawn crowing before light onset under 12:12 light : dim light conditions and the free‐running rhythm of crowing under total dim light conditions. We next examined the crowing rhythms under semi‐wild conditions. Although the crowing of red jungle fowls changed seasonally under semi‐wild conditions, predawn crowing was observed before sunrise in all seasons. This evidence suggests that seasonally changed crowing of red jungle fowls is under the control of a circadian clock.     

The T allele at the g.1471620G>T in the EDG1 gene associated with high marbling in Japanese Black cattle is at a low frequency in breeds not selected for marbling

Our previous study detected a single nucleotide polymorphism (SNP), g.1471620G > T , in the 5' flanking region of the endothelial differentiation sphingolipid G-protein-coupled receptor 1 ( EDG1 ) gene, which has been considered as a positional functional candidate for the gene responsible for marbling, and showed association of the g.1471620G > T SNP with marbling in Japanese Black beef cattle. In the present study, we investigated the allele frequency distribution of the g.1471620G > T SNP among the 5 cattle breeds, Japanese Black, Japanese Brown, Japanese Short Horn, Holstein, and Brown Swiss breeds. The T allele at the g.1471620G > T SNP associated with high marbling was found at high frequency in Japanese Black breed that has been subjected to a strong selection for high marbling, while the allele was absent or at very low frequencies in the other breeds that have not been strongly selected for high marbling. Based on this finding, we hypothesized that the pressure of the strong selection for high marbling in Japanese Black breed has increased the frequency of the T allele at the g.1471620G > T SNP in the EDG1 .     

Surveillance and characterization of Newcastle disease viruses isolated from northern pintail (Anas acuta) in Japan during 2006-09

A total of 38 Newcastle disease virus (NDV) isolates were obtained from 6060 fecal samples from northern pintail (Anas acuta) ducks collected in the Tohoku district in Japan during 2006-09. One isolate from each sampling location and date was selected for a total of 38 isolates, then 15 of these were characterized for their pathogenicity by mean death time of minimum lethal dose (MDT/MLD) using chicken embryos and by plaque formation on chicken embryo fibroblasts. Furthermore, nine isolates were randomly selected from these 15 isolates, and the fusion protein genes were sequenced to characterize amino acid sequences around the cleavage site. All 15 were confirmed to be nonvirulent by MDT/MLD test, and nine isolates were also confirmed as nonvirulent by the cleavage site of the fusion protein 112G/E-K/R-Q-G/E-R*L117 that was specific for nonvirulent NDVs. The characteristics of nine isolates identified by phylogenic analysis of the fusion protein gene indicated that the isolates belong to genotype I or II. In addition, we also isolated 68 avian influenza viruses and 28 other hemagglutinating viruses. Our data indicate that northern pintails are subclinically infected by, perpetuate, and distribute NDV along with different subtypes of avian influenza viruses and other hemagglutinating viruses during their migrations across vast areas over the Northern Hemisphere to Japan.     

Characterization of monoclonal antibodies against canine P-selectin glycoprotein ligand-1 (PSGL-1)

Thirteen different monoclonal antibodies against canine P-selectin glycoprotein ligand-1 (cPSGL-1) were obtained by immunization of rats with cells of a canine lymphoma cell line (Ema). O-sialoglycoprotein endopeptidase treatment of Ema cells showed that all of these antibodies recognized O-glycosylated peptides of canine PSGL-1. Experiments using deletion or point mutants of cPSGL-1 indicated that these antibodies could be categorized into several groups based on their cPSGL-1 recognition characteristics. These anti-cPSGL-1 monoclonal antibodies will be useful for analysis of the canine P-selectin and PSGL-1 system.     

Genetic and genomic analyses for predicted methane‐related traits in Japanese Black steers

The objectives of this study were to estimate genetic parameters and to perform a genome‐wide association study (GWAS) for predicted methane‐related traits in Japanese Black steers. The methane production and yield traits were predicted using on‐farm measurable traits, such as dry matter intake and average daily gain. A total of 4,578 Japanese Black steers, which were progenies of 362 sires genotyped with imputed 551,995 single nucleotide polymorphisms (SNPs), had phenotypes of predicted methane‐related traits during the total fattening period (52 weeks). For the estimation of genetic parameters, the estimated heritabilities were moderate (ranged from 0.57 to 0.60). In addition, the estimated genetic correlations of methane production traits with most of carcass traits and feed‐efficiency traits were unfavorable, but those of methane yield traits were favorable or low. For the GWAS, no genome‐wide significant SNP was detected, but a total of four quantitative trait locus (QTL) regions that explained more than 5.0% of genetic variance were localized on the genome, and some candidate genes associated with growth and feed‐efficiency traits were located on the regions. Our results suggest that the predicted methane‐related traits are heritable and some QTL regions for the traits are localized on the genome in Japanese Black steers.     

Establishment and characterization of a canine sebaceous epithelial cell line derived from an eyelid mass

Little is known about the pathological roles of sebaceous glands in canine skin diseases, as most examinations have been conducted with cultured human sebaceous epithelial cell lines. To our knowledge, there is no available canine sebaceous epithelial cell line. The purpose of this study was to establish a canine sebaceous epithelial cell line and characterize it. An eyelid mass in a dog was surgically resected for treatment, and it was histologically diagnosed as sebaceous epithelioma. Collected tissue was conducted for culture, and the growing epithelial-like cells were passaged. The cells showed continuous proliferation for over 6 months. After 40 passages, the cells were named CMG-1. Lipid droplets in the cytoplasm of CMG-1 cells were confirmed by Oil Red O staining. As reported in studies with human sebaceous epithelial cell lines, lipogenesis in CMG-1 cells was promoted by linoleic acid, whereas transforming growth factor-β (TGF-β) suppressed it. Additionally, real-time PCR revealed that the expression levels of chemokines and cytokines, including CC chemokine ligand (CCL)-2, CCL-20, CXCL-10, Tumor necrosis factor-α (TNF-α), Interleukin (IL)-1α, IL-1β, and IL-8, were significantly increased in CMG-1 cells following treatment with lipopolysaccharide. In conclusion, we successfully established a new canine sebaceous epithelial cell line. Our data indicated that lipogenesis and inflammatory responses were quantitatively evaluable in this cell line. CMG-1 cells could be useful for the pathological analysis of sebaceous gland diseases in dogs.     

Increased total nitrogen content of poultry manure by decreasing water content through composting processes

Microbial mineralization of urea and uric acid in poultry litter can lead to loss of nitrogen (N) content and its value as a fertilizer. To minimize the loss of N in the composting processes, controlling the water content in litters is a key to reduce the mineralization processes of N compounds. The N content of litter may be influenced by diets, hen age and the type of poultry houses used. The objectives of the present study were i) to determine the relationship between the water content and the decomposition rate of uric acid in poultry litter and ii) to investigate the effect of hen age and crude protein (CP) percentages in diets on the N content of poultry litter. A layer feeding trial was conducted in two poultry farms with windowless and open-floor houses. An incubation study of poultry litter was performed under different levels of water content. Our study found that the diet CP percentage (16.5–18%) and the growth stage of laying hens did not have a significant effect on the amount of total N (52–56?g?kg^?1) and uric acid-N (26–31g?kg^?1) in fresh litters. At the 7^th day of litter incubation study, the concentration of uric acid-N was 22 g kg^?1 in litters with a water content of 35%, whereas it further decreased to less than 1.3 g kg^?1 in litters with a water content of 55% and higher levels. The decomposition rate of uric acid-N in litter was 0.3–3.1g?kg^?1?day^?1 in the windowless house and 3.1–7.1g?kg^?1?day^?1 in the open-floor house. Decomposition of uric acid in litters was positively correlated to the litter moisture content that is controlled to be lower in windowless houses (40–50%) than in open-floor houses (55–80%) during the composting period. Our study suggests that the use of windowless houses for layer chicken production is effective for producing poultry manure with a high N content.     

Surface-active properties of particle size fractions in two humic acids

The relationships between surface active properties and humic acid (HA) particle sizes were investigated. Two HAs from an Ando soil and a Brown forest soil were separated into 6 particle size fractions by gel permeation chromatography. Surface-active properties characterized by surface excess value (\gT mol cm^-2), cross-sectional surface area per molecule (A nm²), critical micelle concentration (CMC g L^-1), efficiency and effectiveness of water surface tension reduction were obtained by the measurement of the surface tension of HA solutions from different particle size fractions. For the HA from the Ando soil, except for the smallest particle size fraction, increasing particle size enhanced the efficiency of reduction of the water surface tension and decreased the CMC, while the effectiveness of reduction of the water surface tension was about the same. The surface activity of the HA from the Ando soil increased with increasing particle size. This phenomenon was similar to the surface activity of a homologous series of surfactants, which increased with increasing alkyl chain length. For the HA from the Brown forest soil, the smallest particle size fraction and three large fractions showed a high efficiency, namely a high surface activity. The smallest fraction from the Brown forest soil showed the highest efficiency and the lowest CMC value. In both HAs, the smallest particle size fraction showed exceptional surface-active properties compared with the other fractions and three fractions with large particle size showed a higher surface activity than other smaller fractions.