Structural and physical properties ofAntheraea pernyi silk fibroin fiber treated with I2-KI aqueous solution

Silk fibroin (SF) fiber from theAntheraea pernyi silkworm was treated with a 1.23 N iodine-potassium iodide (I₂-KI) aqueous solution, and the structure and physical properties were investigated to clarify the effects of the iodine treatment. The noticeably high weight gain value of SF fiber, about 25 wt% was attributed to the absorption of polyiodide ions in the form of I₃ ^? and I₅ ^?. Fourier transform infrared spectroscopy and X-ray diffraction measurements suggested that polyiodide ions mainly entered the amorphous region. In addition, a new sharp reflection on the meridional direction, corresponding to a period of 7.0 Å, was observed and indicated the possibility of the formation of mesophase structure ofβ-conformation chains. Dynamic viscoelastic measurements showed that the damping tanδ peak at 270°C gradually shifted to lower temperature in the iodinated SF fibers, suggesting an enhancement of the molecular motion of the fibroin chains induced by the presence of polyiodide ions. With heating above 254 °C, the iodine component introduced intermolecular cross-linking of SF, and the melt flow of the sample was inhibited. The thermal decomposition stability of fibroin molecules was greatly enhanced by iodine treatment.     

Partial characterization of phylogeny,ecology and function of the fibrolytic bacterium Ruminococcus flavefaciens OS14, newly isolated from the rumen of swamp buffalo

The fibrolytic rumen bacterium Ruminococcus flavefaciensOS14 was isolated from swamp buffalo and its phylogenetic, ecological and digestive properties were partially characterized. Isolates from rumen contents of four swamp buffalo were screened for fibrolytic bacteria; one of the 40 isolates showed a distinctive feature of solubilizing cellulose powder in liquid culture and was identified as R. flavefaciens based on its 16S ribosomal DNA sequence. This isolate, OS14, was employed for detection and digestion studies, for which a quantitative PCR assay was developed and defined cultures were tested with representative forages in Thailand. OS14 was phylogenetically distant from other isolated and uncultured R. flavefaciens and showed limited distribution among Thai ruminants but was absent in Japanese cattle. OS14 digested rice straw and other tropical forage to a greater extent than the type strain C94 of R. flavefaciens. OS14 produced more lactate than C94, and digested para grass to produce propionate more extensively in co‐culture with lactate‐utilizing Selenomonas ruminantium S137 than a co‐culture of C94 with S137. These results indicate that phylogenetically distinct OS14 could digest Thai local forage more efficiently than the type strain, possibly forming a symbiotic cross‐feeding relationship with lactate‐utilizing bacteria. This strain might be useful for future animal and other industrial applications.     

Equine coronavirus induces apoptosis in cultured cells

Equine coronavirus (ECoV) was first isolated from a diarrheic foal and was found genetically similar to group II coronaviruses. However, its pathological characteristics were not adequately investigated. In our preliminary in vitro investigation, ECoV-induced cell death was observed in bovine kidney-derived MDBK cells. Based on this finding, we investigated whether the ECoV-induced CPE was apoptosis. Following ECoV infection, MDBK cells showed morphological changes such as cell rounding and detachment from the culture surface. Moreover, syncytium formation was observed as the other type of cytopathic effect in ECoV infection. Morphologic and biochemical features of apoptosis, such as nuclear fragmentation and DNA ladder formation, were also detected in ECoV-infected cells. Moreover, as is commonly observed in coronavirus infection in other animals, the activities of effecter caspases – caspase-3/7 – and initiator caspases – caspase-8 and caspase-9 – that are representative factors in the death receptor-mediated apoptotic pathway and mitochondrial apoptotic pathway, respectively, were increased in ECoV-infected MDBK cells. Therefore, it was suggested that ECoV can induce apoptosis in MDBK cells via a caspase-dependent pathway. Apoptotic death of infected cells is detrimental because it causes cell and tissue destruction and inflammatory responses. Although the pathological characteristics of ECoV are largely unknown, apoptosis may be the pathological basis of lesions of the digestive system in ECoV infection.     

Effect of SCD and SREBP genotypes on fatty acid composition in adipose tissue of Japanese Black cattle herds

Fatty acid composition of beef adipose tissue is one of important traits because high proportions of monounsaturated fatty acid are related to favorable beef flavor and tenderness. In this study, we investigated effects of genetic factors such as stearoyl-CoA desaturase (SCD) and sterol regulatory element binding protein (SREBP) on beef carcass traits including fatty acid composition using two cattle populations. Sire effect was significantly related to almost all traits except BMS, suggesting that the trait examined in this study is highly controlled by genetic factors. The effect of SCD genotype on fatty acid composition was detected remarkably in both cattle groups, especially on stearic and oleic acids. This result was consistent with our previous studies and suggests that SCD is associated with fatty acid composition. Unlike SCD genotyping, the effect of SREBP genotype was not identified in this study. Our results suggested that SCD genotype would contribute to improving beef quality in field populations. Further studies about the relationship among these factors will bring an insight into the molecular mechanism of fatty acid metabolism in cattle.     

Phylogenetic analysis of hindgut microbiota in Hokkaido native horses compared to light horses

The analysis of 16S rDNA sequence of bacteria in feces of Hokkaido native horses and light horses were performed to compare the hindgut microbiota between the two breeds. One hundred and four bacterial 16S rDNA clones (57 clones from four native horses and 47 clones from two light horses) were obtained. Only four sequences (3.8% of total sequences) showed 97% or more similarity to known species. The sequences were mainly affiliated with Cytophaga–Flavobacter–Bacteroides and low GC Gram‐positive bacteria (LGCGP). Proportion of LGCGP was higher in light horses. Other phyla including Verrucomicrobia, Spirochaetes and Archaea were detected only for native horses, suggesting high diversity of microbiota in native horses. In LGCGP, clusters related to known cellulolytic species were found only for native horses, while a cluster related to soluble sugar‐utilizing species was detected only for light horses. The library composition‐comparing software LIBSHUFF showed significant (P < 0.05) difference of fecal microbiota between the horse breeds. The number of Fibrobacter succinogenes‐related sequence and the frequency of detection of novel groups were found to be higher in native horses by selective amplification analysis. The results suggest that genetic diversity and population size of the F. succinogenes group are higher in the hindgut of native horses.     

Phase transition of FeO and stratification in Earth's outer core

Light elements such as oxygen in Earth's core influence the physical properties of the iron alloys that exist in this region. Describing the high-pressure behavior of these materials at core conditions constrains models of core structure and dynamics. From x-ray diffraction measurements of iron monoxide (FeO) at high pressure and temperature, we show that sodium chloride (NaCl)-type (B1) FeO transforms to a cesium chloride (CsCl)-type (B2) phase above 240 gigapascals at 4000 kelvin with 2% density increase. The oxygen-bearing liquid in the middle of the outer core therefore has a modified Fe-O bonding environment that, according to our numerical simulations, suppresses convection. The phase-induced stratification is seismologically invisible but strongly affects the geodynamo.     

Localization of interleukin-6 receptor mRNA in the pregnant and non-pregnant mouse uterus

To understand roles of interleukin 6 (IL-6) family cytokines for pregnancy in mice, localization of IL-6 receptor (IL-6R) mRNA was investigated in non- and early pregnant uteri by in situ hybridization. IL-6R mRNA was expressed in all non-pregnant uteri and in pregnant uteri from the third day (Day 3) to the sixth day of pregnancy (Day 6; the day of plug = Day 1). IL-6R mRNA signals were detected in non-pregnant mice in the luminal and glandular epithelium. Signal strength varied according to the sexual cycle. There was no correlation between the signal strength of the IL-6R mRNA and the serum concentrations of progesterone and 17beta-estradiol, which show a monophasic rise in the non-pregnant sexual cycle. In pregnant mice, slight signals were detectable in the luminal and glandular epithelium on Day 3. IL-6R mRNA messages increased with progression towards Day 4, however, localization changed drastically on Day 5. Stromal cells abruptly expressed their mRNA on Day 5, and these cells strongly expressed it on Day 6. The function of IL-6R in the luminal and glandular epithelium might be different from that in the stroma during the implantation period. In addition, few signals were identified in the stromal cells adjacent to the luminal epithelium on Day 6. This suggests that there are two types of stromal cells on Day 6 in mice.     

Genetic population structure of the Pacific bluefin tuna Thunnus orientalis and the yellowfin tuna Thunnus albacares in the North Pacific Ocean

The genetic population structure of the Pacific bluefin tuna (PBF) Thunnus orientalis and the yellowfin tuna (YFT) T. albacares in the North Pacific Ocean was investigated. The polymorphism of microsatellite (SSR) loci and sequences of mitochondrial DNA control region (mtCR) were analyzed for 71 samples of PBF from Japan and Mexico and 45 samples of YFT from Japan and Panama. In the SSR analyses, both single-locus (?0.010 to 0.008 in PBF and ?0.023 to 0.020 in YFT) and global multilocus (0.003 in PBF and ?0.002 in YFT) F _ST values among the geographic populations were low and not significant in these species. In the mtCR analyses, neither the neighbor-joining tree nor the minimum spanning network showed genetic differentiation among the geographic populations in each species. The pairwise F _ST values among the geographic populations of them (?0.005 in PBF and ?0.020 to ?0.014 in YFT) were low and not significant. Our SSR and mtCR data suggested that genetic differentiations were not evident among the eastern and western populations in the North Pacific Ocean either in PBF or in YFT. Mismatch distributions, demographic parameters, and neutrality tests suggested that sudden population expansion of PBF and YFT in the North Pacific Ocean occurred 628,000–731,000 and 450,000–525,000 years ago, respectively.     

Presence of surfactant proteins in the uteri and placentae of pregnant mares

Immunohistochemical investigations of the expression of surfactant protein A (SP-A) and surfactant protein D (SP-D) in the uterine and placental tissues of 13 pregnant mares were performed using anti-horse monoclonal primary antibodies. Strong positive reactions for both SP-A and SP-D were observed in the trophoblasts in the microcotyledons of the placentae at 182 to 314 days of gestation; in uterine glandular epithelial cells, faint-to-weak reactions were observed during gestation. This study describes, for the first time, the changes in the SP-A and SP-D expression levels in the endometrium of mares during gestation; the SP-A and SP-D expression levels increased after the second trimester of gestation.