Genetic diversity of group A rotaviruses associated with repeated outbreaks of diarrhea in a farrow-to-finish farm: identification of a porcine rotavirus strain bearing a novel VP7 genotype, G26

ABSTRACT: Group A rotaviruses (GARs) are one of the most common causes of diarrhea in suckling pigs. Although a number of G and P genotypes have been identified in porcine GARs, few attempts have been made to study the molecular epidemiology of these viruses associated with diarrhea outbreaks within a farm over an extended period of time. Here, we investigated the molecular characteristics of GARs that caused four outbreaks of diarrhea among suckling pigs in a farrow-to-finish farm over the course of a year. G and P genotyping of GARs detected at each outbreak demonstrated genetic diversity in this farm as follows: G9P[23] was detected at the first outbreak, G9P[13]/[22] and G9P[23] at the second, G3P[7] at the third, and G9P[23], G5P[13]/[22], and P[7] combined with an untypeable G genotype at the fourth. Sequence analysis of the detected GARs revealed that such genetic diversity could have resulted not only from the introduction of new GAR strains, but also from gene reassortment between GAR strains within the farm. Further, the GAR strain carrying the untypeable G genotype was shown to be a novel porcine GAR bearing a new G26 genotype, as confirmed by the Rotavirus Classification Working Group.     

Immunoreactivity and morphological changes of bursal follicles in chickens infected with vaccine or wild-type strains of the infectious bursal disease virus

Infectious bursal disease (IBD) is characterized by immunosuppression due to the depletion of lymphocytes in the atrophied bursa of Fabricius (BF). We have sometimes encountered contradictory findings: chickens infected with the vaccine IBD virus (IBDV) strain have sometimes exhibited a highly atrophied BF, but not immunosuppression. In this study, chickens administered vaccine or wild-type strains of IBDV were later vaccinated with the B1 strain of the Newcastle disease virus (NDV). Bursal changes were examined histologically with a focus on the bursal follicle. The immunoreactivity to NDV was also evaluated with the hemagglutination inhibition test. In gross examination, we observed a few chickens with a severely atrophied BF in vaccine strain-administered groups (vaccine groups), and the level of severity was the same as that in the wild-type strain-administered group (wild-type group). However, these chickens retained humoral antibody responses to NDV and were revealed to possess a higher number of bursal follicles than those of the wild-type group. These results indicated that macroscopic evaluation dose not accurately reflect the immunoreactivity and degree of bursal damage in IBDV-administered chickens. We also found non-immunosuppressed chickens in the wild-type group. These non-immunosuppressed chickens retained a significantly higher number of normal follicles and total follicles according to our statistical analysis. Furthermore, a high correlation coefficient between the NDV-HI titer and the number of normal follicles was found in the wild-type group. These results implied that the retained number of normal follicles is important for the immunoreactivity of chickens infected with IBDV.     

Impact of activated charcoal and tannin amendments on microbial biomass and residues in an irrigated sandy soil under arid subtropical conditions

Effects of goat manure application combined with charcoal and tannins, added as feed additives or mixed directly, on microbial biomass, microbial residues and soil organic matter were tested in a 2-year field trial on a sandy soil under Omani irrigated subtropical conditions. Soil microbial biomass C revealed the fastest response to manure application, followed by microbial residue C, estimated on the basis of fungal glucosamine and bacterial muramic acid, and finally soil organic C (SOC), showing the slowest, but still significant response. At the end of the trial, microbial biomass C reached 220 μg g^?1 soil, i.e. contents similar to sandy soils in temperate humid climate, and showed a relatively high contribution of saprotrophic fungi, as indicated by an average ergosterol to microbial biomass C ratio of 0.35 % in the manure treatments. The mean fungal C to bacterial C ratio was 0.55, indicating bacterial dominance of microbial residues. This fraction contributed relatively low concentrations of between 20 and 35 % to SOC. Charcoal added to manure increased the SOC content and the soil C/N ratio, but did not affect any of the soil microbial properties analysed. Tannins added to manure reduce the 0.5 M K₂SO₄-extractable N to N total ratio compared to manure control. These effects occurred regardless of whether charcoal or tannins were supplied as feed additive or directly mixed to the manure.     

N-Acetyl-d-Glucosamine-Binding Lectin in Acropora tenuis Attracts Specific Symbiodiniaceae Cell Culture Strains

Many corals establish symbiosis with Symbiodiniaceae cells from surrounding environments, but very few Symbiodiniaceae cells exist in the water column. Given that the N-acetyl-d-glucosamine-binding lectin ActL attracts Symbiodiniaceae cells, we hypothesized that corals must attract Symbiodiniaceae cells using ActL to acquire them. Anti-ActL antibody inhibited acquisition of Symbiodiniaceae cells, and rearing seawater for juvenile Acropora tenuis contained ActL, suggesting that juvenile A. tenuis discharge ActL to attract these cells. Among eight Symbiodiniaceae cultured strains, ActL attracted NBRC102920 (Symbiodinium tridacnidorum) most strongly followed by CS-161 (Symbiodinium tridacnidorum), CCMP2556 (Durusdinium trenchii), and CCMP1633 (Breviolum sp.); however, it did not attract GTP-A6-Sy (Symbiodinium natans), CCMP421 (Effrenium voratum), FKM0207 (Fugacium sp.), and CS-156 (Fugacium sp.). Juvenile polyps of A. tenuis acquired limited Symbiodiniaceae cell strains, and the number of acquired Symbiodiniaceae cells in a polyp also differed from each other. The number of Symbiodiniaceae cells acquired by juvenile polyps of A. tenuis was correlated with the ActL chemotactic activity. Thus, ActL could be used to attract select Symbiodiniaceae cells and help Symbiodiniaceae cell acquisition in juvenile polyps of A. tenuis, facilitating establishment of symbiosis between A. tenuis and Symbiodiniaceae cells.     

The formation process of button ulcers in pigs experimentally infected with a subgenotype 2.1 isolate of classical swine fever virus

We evaluated the role of classical swine fever virus (CSFV) in the formation of button ulcers in the mucosa of the gastrointestinal tract. Histopathological and immunohistochemical analyses of pigs experimentally infected with a subgenotype 2.1 isolate of CSFV, which was isolated in Japan in 2019, revealed follicular necrosis in the submucosal mucosa-associated lymphoid tissue and herniation of crypts as factors that contribute to the development of button ulcers during CSFV infection. These findings indicate that CSFV induces follicular necrosis and is one of the causative agents of button ulcers in pigs.     

Large-scale survey of frequency of forest walking and related factors in a Japanese population inhabiting a large city, and comparison of an urban area and a rural area

The frequency of forest walking among the general population is a major topic of study in forest science. The objectives of this study were threefold: to assess the frequency of forest walking among Japanese residents of Nagoya, a large city; to evaluate differences among frequency of forest walking by participants from a large city, an urban area (Shizuoka; 4,666 participants), and a rural area (Yakumo Town, Hokkaido; 397 participants) in previous studies; and to examine factors related to frequency of forest walking. The survey, by self-administered questionnaire, in the major city of Nagoya was conducted between June 2008 and May 2010. In all, 5,158 participants (M/F, 1,466/3,692; mean age ± SD [range], 52.5 ± 10.3 [35–69] years) were included in the analysis. The proportions of frequency of forest walking ≥ once/month and ≥ once/year were 10.9 % (M/F, 15.1/9.3 %) and 46.1 % (51.0/44.1 %), respectively. In multiple logistic regression analysis, significant differences were noted among study sites for the adjusted odds ratio for frequency of forest walking. Overall, the order of highest to lowest frequency of forest walking was Shizuoka > Nagoya > Yakumo. Factors related to frequency of forest walking were common among the three study sites. Higher frequency of forest walking was associated with male sex and older age; the most relevant factor related to frequency of forest walking was its enjoyment level. Further studies will be required to clarify why these factors are related to frequency of forest walking.     

Expression of Glucocorticoid Receptor α and Its Regulation in the Bovine Endometrium: Possible Role in Cyclic Prostaglandin F2α Production

Cortisol (Cr), the most important glucocorticoid (GC), is well known to suppress uterine prostaglandin F2α (PGF) production. However, the details of the regulatory mechanisms controlling the cyclic changes in endometrial PGF production remain unclear. Here we investigated the expression of the GC receptor (GC-Rα), the actions of cortisol throughout the estrous cycle and the regulatory mechanism of GC-Rα in the bovine endometrium. The levels of GC-Rα protein were greater at the mid-luteal stage (Days 8–12) than at the other stages. Cr more strongly suppressed PGF production at the mid-luteal stage than at the follicular stage. GC-Rα expression was increased by progesterone (P4) but decreased by estradiol-17β (E2) in cultured endometrial stromal cells. The overall results suggest that ovarian steroid hormones control the cyclic changes in endometrial PGF production by regulating GC-Rα expression in bovine endometrial stromal cells.     

Timing of Puberty and Its Relationship with Body Growth and Season in Male Raccoons (Procyon lotor) in Hokkaido

The raccoon (Procyon lotor), indigenous to North America, has naturalized in Japan as an invasive alien species, having been introduced into the country in the 1970s. In Hokkaido, the northernmost island of Japan, feral raccoons have been increasing in number and spreading throughout the island. The age at the onset of puberty for raccoons is important for estimating individual lifetime reproductive success and population growth. The present study investigated the timing of and potential factors affecting the onset of puberty in male raccoons in Hokkaido. External characteristics and histology of testes were studied in 151 male feral raccoons and in 1 captive juvenile. For the majority of feral yearling raccoons, prepubertal development began in May, and spermatozoa production began in October prior to their second mating season. However, some larger juveniles attained puberty during the juvenile period. The captive juvenile, which was fed throughout the winter, attained puberty only 11 months after birth. These results suggest that if male raccoons can achieve enough body growth before the first mating season, puberty can be attained early. In both juveniles and yearlings, spermatozoa production was only observed after autumn. This timing coincided with the recrudescence of seasonally active spermatogenesis in adult males. Therefore, attaining puberty in male raccoons appears to require both adequate body nutrient development and several environmental factors that control seasonal testicular changes.