Chicken B lymphoma DT40 cells as a useful tool for in vitro analysis of pathogenic infectious bursal disease virus

Susceptibility of DT40 cells to pathogenic field strains of infectious bursal disease virus (IBDV) including very virulent and classical virulent strains were studied. After the first and second passage of the virus in DT40 cells, IBDV-specific antigen was readily detected in DT40 cells inoculated with the pathogenic field strain infected bursal homogenates. Nucleotide sequence analysis in the VP2 hypervariable domain, which is critical for the virulence of IBDV, revealed no common amino acid substitutions among the pathogenic IBDVs in accordance with the propagation in DT40 cells. These results indicate that DT40 cells are a useful tool for rapid isolation of pathogenic field strains and successive in vitro analysis of IBDV.     

Genome‐wide association studies identified variants for taurine concentration in Japanese Black beef

We performed genome‐wide association studies (GWAS) using the BovineSNP50 array to detect significant single nucleotide polymorphisms (SNPs) that may affect the concentration of 22 free amino acids and three peptides in Japanese Black beef cattle. A total of 574 Japanese Black cattle and 40,657 SNPs from the array were used for this study. Genome‐wide significant SNPs were detected for β‐alanine (three SNPs on chromosomes 22 and 29) and taurine (26 SNPs on chromosome 22). Importantly, the top two SNPs for taurine were highly significant (p = 6.2 × 10^?21), and the frequency of the increase‐concentration allele (Q) for taurine was found to be 0.73. The Q allele frequency of this population was similar to that of the other unrelated Japanese Black cattle, but different from that of the other breeds. In addition, the significant SNPs were not associated with carcass traits or fatty acid compositions. Interestingly, the top three of the four most significant SNPs for taurine were located near solute carrier family 6, member 6 (SLC6A6), which is a membrane transporter for taurine. We also found two associated variants in the 5′‐upstream region of SLC6A6; however, they were less significantly associated than the SNPs from the BovineSNP50 array.     

Photosynthesis and biomass allocation of beech (Fagus crenata) and dwarf-bamboo (Sasa kurilensis) in response to contrasting light regimes in a Japan Sea-Type beech forest

Regeneration of beech (Fagus crenata) forests depends on the formation of canopy gaps. However, in Japan Sea-type beech forests, a dwarf bamboo (Sasa kurilensis) conspicuously occupies sunny gaps. Therefore,F. crenata seedlings must escape the severe interference ofS. kurilensis in the gaps and persist beneath a closed canopy of the beech forest. We hypothesized that the growth ofF. crenata seedlings in the understory would be favored by their being more plastic thanS. kurilensis in photosynthetic and morphological traits, which would support the matter production ofF. crenata seedlings in a wide range of light availabilities. To examine this hypothesis, the photosynthetic-light response of individual leaves and the biomass allocation in aboveground parts (i.e., the culm/foliage ratio) were surveyed at sites with contrasting light availabilities in a Japan Sea-type beech forest in central Japan. InF. crenata, photosynthetic light utilization efficiency at relatively low light was greater, and the dark respiration rate was smaller in the leaves of seedlings (10 cm in height) beneath the closed canopy than in the leaves of saplings at the sunny forest edge. The culm/foliage (C/F) ratio of theF. crenata seedlings at the shady site was small, suggesting effective matter-production beneath the beech canopy. On the other hand,S. kurilensis both in the gap and beneath the beech canopy showed low plasticity in photosynthesis and the culm/foliage ratio. Because the shoot density ofS. kurilensis was smaller beneath the beech canopy than in the gap, the light availability at the bottom of theS. kurilensis layer was greater beneath the beech canopy. These results suggest that the photosynthetic productivity of theF. crenata seedlings would be enough for the seedlings to survive in the understory with a low density ofS. kurilensis shoots beneath the closed beech canopy.     

Profiling of Polar Lipids in Marine Oleaginous Diatom Fistulifera solaris JPCC DA0580: Prediction of the Potential Mechanism for Eicosapentaenoic Acid-Incorporation into Triacylglycerol

The marine oleaginous diatom Fistulifera solaris JPCC DA0580 is a candidate for biodiesel production because of its high lipid productivity. However, the substantial eicosapentaenoic acid (EPA) content in this strain would affect the biodiesel quality. On the other hand, EPA is also known as the essential health supplement for humans. EPAs are mainly incorporated into glycerolipids in the microalgal cell instead of the presence as free fatty acids. Therefore, the understanding of the EPA biosynthesis including the incorporation of the EPA into glycerolipids especially triacylglycerol (TAG) is fundamental for regulating EPA content for different purposes. In this study, in order to identify the biosynthesis pathway for the EPA-containing TAG species, a lipidomic characterization of the EPA-enriched polar lipids was performed by using direct infusion electrospray ionization (ESI)-Q-TRAP-MS and MS/MS analyses. The determination of the fatty acid positional distribution showed that the sn-2 position of all the chloroplast lipids and part of phosphatidylcholine (PC) species was occupied by C16 fatty acids. This result suggested the critical role of the chloroplast on the lipid synthesis in F. solaris. Furthermore, the exclusive presence of C18 fatty acids in PC highly indicated the biosynthesis of EPA on PC. Finally, the PC-based acyl-editing and head group exchange processes were proposed to be essential for the incorporation of EPA into TAG and chloroplast lipids.     

Molecular characterization of avian polyomavirus isolated from psittacine birds based on the whole genome sequence analysis

Seven avian polyomaviruses (APVs) were isolated from seven psittacine birds of four species. Their whole genome sequences were genetically analyzed. Comparing with the sequence of BFDV1 strain, nucleotide substitutions in the sequences of seven APV isolates were found at 63 loci and a high level of conservation of amino acid sequence in each viral protein (VP1, VP2, VP3, VP4, and t/T antigen) was predicted. An A-to-T nucleotide substitution was observed in non-control region of all seven APV sequences in comparison with BFDV1 strain. Two C-to-T nucleotide substitutions were also detected in non-coding regions of one isolate. A phylogenetic analysis of the whole genome sequences indicated that the sequences from the same species of bird were closely related. APV has been reported to have distinct tropism for cell cultures of various avian species. The present study indicated that a single amino acid substitution at position 221 in VP2 was essential for propagating in chicken embryonic fibroblast culture and this substitution was promoted by propagation on budgerigar embryonic fibroblast culture. For two isolates, three serial amino acids appeared to be deleted in VP4. However, this deletion had little effect on virus propagation.     

Spinal nephroblastoma in a miniature Dachshund

A 2-year-old castrated miniature Dachshund dog was presented to the Rakuno Gakuen Veterinary Teaching Hospital for diagnosis of progressive hindlimb paresis and ataxia. There was no thoracolumbar intervertebral disk hernia and magnetic resonance imaging revealed an intramedullary spinal cord lesion at the ninth and tenth thoracic vertebrae. Following surgical excision of the neoplasm, there was minor amelioration of neurological signs, but forelimb function was not recovered. The extracted tumor was histopathlogically diagnosed as spinal nephroblastoma.     

Synergistic effect of heartwood extractives and quaternary ammonium compounds on termite resistance of treated wood

This study evaluates the synergistic effect of wood extractives and quaternary ammonium compounds (QACs) on the resistance to termites of several treated wood species. Wood specimens from different natural durability classes were extracted with either hot water alone or hot water + ethanol/benzene. The extracted and unextracted wood specimens were treated with either didecyldimethylammonium tetrafluoroborate (DBF) or commercial didecyldimethylammonium chloride (DDAC) solutions and then exposed to subterranean termites, Coptotermes formosanus Shiraki, for 3 weeks under laboratory conditions. The results showed that extractives of the heartwood portions of the wood species contributed to increased resistance against termite attack in the presence of either DBF or DDAC wood preservatives. The synergistic effect of wood extractives and DBF was much clearer with Pseudotsuga menziesii (Mirbel) Franco and Tsuga heterophylla Sarg wood samples. Further studies are needed for a better understanding of the synergism between wood extractives and either DBF or DDAC using both the sapwood and heartwood portions of the same wood species.     

Calcium-sensitive extracellular poly(α-L-guluronate)lyase from a marine bacterium Pseudomonas sp. strain F6: Purification and some properties

ABSTRACT: Poly(α- L -guluronate)lyase, as one of alginate lyases, was purified from the culture medium of a marine bacterium, Pseudomonas sp. strain F6, to an electrophoretically homogeneous state. The enzyme was shown to have a molecular mass of 36 kDa by sodium dodecylsulfate–polyacrylamide gel electrophoresis (SDS-PAGE), and was most active at around pH 7.5 and was stable between pH 6.5 and pH 8.5. In the thermal stability experiments, the enzyme's activity diminished through an intermediate state with increasing incubation temperatures and was finally lost when heated at 100°C for 15 min. The addition of hen egg-white lysozyme to the enzyme decreased thermal stability dramatically. The apparent retention of enzyme activity (approximately 50%) was observed after the addition of 6 M guanidine hydrochloride and 8 M urea. Enzyme activity was lost completely with 10 mMSDS, while the ordered structure, which is considered likely to be β-structure, was markedly created. The similar conformational feature has also been created in marine bacterial and mollusc enzymes and the β-structure is commonly observed in polyuronate lyases. The divalent cation (Ca²⁺) promoted the activity of the calcium chelator-treated enzyme significantly, suggesting that Ca²⁺ is involved in the formation of the active intermediate between the acidic uronate(s) and amino acid side-chain(s) of the enzyme.