Anti-influenza A virus activities of mannan-binding lectins and bovine conglutinin

Mannan-binding lectin (MBL) and bovine conglutinin (BKg) belong to the collectin family, which is involved in first-line host defense against various infectious agents. We have previously reported that human MBL inhibited type A influenza viral hemagglutination, infection and spreading to adjacent cells without complement activation. In this study, we investigated the direct antiviral activities of bovine MBL, rabbit MBL and BKg. All collectins used in this study inhibited viral infectivity and hemagglutination at concentrations of 0.02-0.3 microg/ml. They also demonstrated inhibitory activity against viral spreading. Like human MBL, bovine MBL and BKg showed antiviral activities at their physiological concentrations. These results suggest that mammalian MBLs and BKg may inhibit the spread of influenza A virus through the bloodstream.     

Experimental infection by Yersinia ruckeri O1 biotype 2 induces brain lesions and neurological signs in rainbow trout (Oncorhynchus mykiss)

Pathological manifestations in rainbow trout (Oncorhynchus mykiss) following experimental waterborne infection with Yersinia ruckeri serotype O1 biotype 2 (strain 07111224) were investigated. Rainbow trout were exposed to 8 × 10⁷ CFU/ml of Y. ruckeri by bath for 6 hr, and mortality was then monitored for 22 days post‐infection (dpi). Organs were sampled at 3 dpi and also from moribund fish showing signs of severe systemic infection such as bleeding, exophthalmia or erratic swimming behaviour. Y. ruckeri was observed in the meninges and diencephalon of the brain, and lamina propria of olfactory organ at 3 dpi. At 12 dpi, Y. ruckeri had spread throughout the brain including cranial connective tissues and ventricles and the infection was associated with haemorrhages and an infiltration with leucocytes. Y. ruckeri infection and associated with leucocyte infiltration were observed at 13 dpi. In conclusion, Y. ruckeri strain 07111224 causes encephalitis in the acute phase of infection, which could explain why Y. ruckeri‐affected fish show exophthalmia and erratic swimming known as signs of ERM.     

Effect of annual rings on abrasive wear property of wood

In this study we investigated the abrasive wear property of Douglas fir (Pseudostuga menziesii Franco) on abrasive paper using test specimens with various dimensions and annual ring widths. The effect of the annual rings on the abrasive wear property of Douglas fir was clarified from the relation with the compression strength of the wood specimens. The dispersion of the wear coefficient, which was calculated as the wear volume divided by the friction distance and the load applied to the friction surface, varied when there were fewer than approximately three annual rings in the specimen, as did the compression strength. As clarified from these results, it was found that the effect of the annual rings on the abrasive wear and compression properties of Douglas fir is closely related to the earlywood/ latewood ratio.Part of this report was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000     

Performance of coated carbide tools in turning wood-based materials: Effect of cutting speeds and coating materials on the wear characteristics of coated carbide tools in turning wood-chip cement board

This paper reports on the performance of coated carbide tools in turning wood-chip cement board. The coating materials studied were titanium carbonitride (TiCN), titanium nitride (TiN), chromium nitride (CrN), and titanium nitride/aluminum nitride (TiN/AlN), which were synthesized on the P30 carbide substrate. The aim is to investigate the effect of coating materials and cutting speeds on the wear characteristics of the coated carbide tools. Cutting tests were performed when turning wood-chip cement board at cutting speeds of 30, 40, 50 and 60 m/s, a depth of cut of 1mm, and a feed of 0.05 mm/rev. The results of the study show that the coated carbide tools provided better performance than the P30 carbide tool, especially in terms of reducing the progression of the wear rate and clearance wear. The TiN/AlN-coated carbide tool showed the smallest increase in both wear rate and clearance wear with an increase in cutting speed and had the longest tool life among the coated carbide tools investigated. Though the TiCN-coated carbide tool was observed to have a low wear rate and low clearance wear for cutting speeds of 30 and 40m/s, when the cutting speeds were >50m/s its wear rate and clearance wear were almost the same as those of CrN-and TiN-coated carbide tools, which had high values for these parameters.Part of this paper was presented at the 21st IUFRO World Congress, August 2000, Kuala Lumpur, Malaysia     

Effect of shear deflection on vibrational properties of compressed wood

In this paper, we have investigated vibrational properties of compressed Japanese cedar (Cryptomeria japonica D. Don). The test specimens were compressed in the radial direction at 180°C for 5 h. Compression ratios (the ratio of deformation to the initial thickness) were 33% and 67%, and the vibrational properties were measured by free-free flexural vibration test. The contribution of shear deflection was large when the length-to-depth ratio was small and the Youngs modulus to shear modulus ratio was large. The Youngs to shear modulus ratio increased as the compression ratio increased and was larger under vibration in the radial than in the tangential direction. The loss tangent increased when the contribution of shear deflection to total measured flexural deflection increased.     

Identification and determination of antigenic proteins of Korean ranavirus-1 (KRV-1) using MALDI-TOF/TOF MS analysis

Ranaviruses are serious pathogens of fish, amphibians, and reptiles, and pose a major threat to global biodiversity. A ranavirus isolated from tissues of diseased tadpoles and frogs in Gangwon province, Korea, in 2006 and 2007, was designated Korean ranavirus-1 (KRV-1) and was infectious in a variety of fish cell lines with highest titers (10¹⁰ TCID₅₀/ml) in Epithelioma papulosum cyprini cells (EPCs) and baby hamster kidney-21 (BHK-21) cells. Bullfrog (Rana catesbeiana) tadpoles challenged by immersion in 10⁵ TCID₅₀/ml of KRV-1 showed 60% mortality within 10 days. SDS-PAGE of frog virus 3 (FV3) and KRV-1 proteins yielded several bands 35-49 kDa in size, which were identified as major capsid proteins (MCPs) by MALDI-TOF MS. Immunoblotting of FV3 proteins showed antigenic bands 34 kDa and 93 kDa in size which were identified by MALDI-TOF/TOF MS as MCP and neurofilament triplet H1-like protein (NF-H1), respectively. In KRV-1, antigenic bands at 32 kDa, 69 kDa, and 72 kDa were identified as MCP, Hypothetical protein, and NF-H1, respectively. The genes encoding these KRV-1 proteins were sequenced. KRV-1 appeared to be closely related to the soft-shelled turtle iridovirus (STIV), based on alignments of amino acid sequences from various ranaviruses. Variability in ranavirus antigenic proteins was apparent in an earlier study. It is expected that use of the methods employed here, together with the results of the present work, will contribute to an understanding of the pathogenesis of ranaviruses, and will further the development of DNA- or protein-based bait vaccines for conservation of natural habitats.     

An improved dry ash procedure for the detection of titanium dioxide in cattle feces

We improved the dry ash procedure for detecting titanium dioxide (TiO₂) in cattle feces containing chromium dioxide (Cr₂O₃). First, the effect of amount of sodium sulfate (Na₂SO₄) on the recovery of TiO₂ from cattle feces that contained Cr₂O₃ was evaluated. Average recovery of TiO₂ at the 2.5 g Na₂SO₄ level was significantly higher (P < 0.0001) than that at 0.75 g Na₂SO₄. Second, the effect of Cr₂O₃ concentration on the recovery of TiO₂ of cattle feces by using two levels of Na₂SO₄ addition was examined. The recovery of TiO₂ decreased with the increase in the amount of Cr₂O₃ at the 0.75 g Na₂SO₄ level but was consistently high at 2.5 g Na₂SO₄. Third, the recovery of Cr₂O₃ from cattle feces was checked. The recoveries of TiO₂ and Cr₂O₃ were high enough at the 2.5 g Na₂SO₄ level. Fourth, the improved dry ash procedure (5 mL of concentrated H₂SO₄ and 2.5 g of Na₂SO₄ were used for sample digestion) was compared to the wet ash procedure. Average recovery of TiO₂ by the improved dry ash procedure was significantly higher (P = 0.0077) than that by the wet ash procedure. Thus, the improved dry ash procedure can be used for TiO₂ analysis in cattle feces containing Cr₂O₃.     

Proliferation of kuchijirosho causative agent in a fugu-derived cell line

Kuchijirosho is a fatal disease of commercially cultured fugu, Takifugu rubripes. The transmissible nature of kuchijirosho strongly suggests that an infectious pathogen is the causative agent. Because it is filtrable, the agent is thought to be a virus; however, it has not yet been identified. The lack of a permissive cell line for the putative kuchijirosho-causing agent (KCA) has hindered research on the identification of this pathogen. We inoculated brain extract prepared from kuchijirosho-affected fugu onto an established fugu cell line, fugu eye, and observed that cytopathic effect appeared 7 days after inoculation. Injection of the culture medium of infected fugu eye cells into fugu resulted in the onset of kuchijirosho, indicating that fugu eye cells are able to proliferate KCA. An infectious fraction separated by sodium iottalamate density gradient centrifugation showed a density of 1.15 g mL(-1) equivalent to that of KCA derived from affected fugu brain. To determine whether the genome of KCA is RNA or DNA based, nucleotide synthesis inhibitors were applied to inoculated fugu eye cell line to influence the production of KCA. 5-Fluorouracil but not IUdR showed a concentration-dependent inhibition of KCA yield. These results suggest that KCA is an RNA virus.