Surveillance of avian influenza viruses in Northern pintails (Anas acuta) in Tohoku District, Japan

Among winter migratory waterfowl, Northern pintails (Anas acuta), in one of the largest flocks in Tohoku district, northeast Japan, were surveyed for influenza A viruses at five wintering sites in three prefectures, viz., Aomori, Akita, and Miyagi. A total of 38 influenza A viruses were isolated from 2066 fecal samples collected during November 2006 through March 2007. The overall isolation rate was 1.84%. Eleven different subtypes were isolated, including nine H5N2, seven H6N8, seven H10N1, four H4N6, three H6N1, three H11N9, and one each of H1N1, H6N2, H6N5, H10N9, H11N1. Only the H4N6 subtype was detected during two successive months, November and December, from Lake Ogawara of Aomori prefecture. One wintering site, Lake Izunuma of Miyagi prefecture, was negative for virus isolation throughout the study period. During the sampling period, the highest virus isolation rate was in December (4.90%) followed by November (2.18%), January (0.91%), and February (0.30%). Virus isolation was negative for samples collected in March 2007. These results suggest that influenza viruses are introduced by Northern pintail when they migrate into Japan, but the viruses are not maintained in the flocks, most likely because the birds are not breeding during the winter. We believe that this relatively large data set creates a strong foundation for future studies of avian influenza virus (AIV) prevalence, evolution, and ecology in wintering sites, along with the role of Northern pintails in the spread of AIV during their migration from northern Russia and Asia to Japan.     

Estimating the annual supply potential and availability of timber and logging residue using forest management records of the Tochigi prefecture, Japan

We used forest management records to estimate the annual supply potential and availability of timber and logging residue from profitable subcompartments for all the cities and towns in the Tochigi prefecture. Five log markets and three factories in the Tochigi prefecture were assumed to be the destination of timber and logging residue, and the forest operation systems were set on the basis of interviews with forestry cooperative officials. The results showed that the annual supply potential of timber and logging residue was 450,304 m³ and 549,957 tons, of which 6 % (26,304 m³) and 37 % (204,122 tons) were from precommercial thinning operations, 61 % (276,180 m³) and 50 % (276,276 tons) were from commercial thinning operations, and 33 % (147,820 m³) and 13 % (69,559 tons) were from final-felling operations, respectively. When the unit price of the logging residue was 10,000 yen/ton, the annual logging residue availability from profitable subcompartments could almost cover the annual demand of the three facilities that we considered in this study. Introduction of feed-in tariffs had a significant impact. However, the ratios of the availability to supply potential with unit prices of logging residue of 3,000, 6,000, and 10,000 yen/ton were estimated to be only 1.67, 2.06, and 4.09 %, respectively. Considering the subsidies, the ratios respectively increased to 5.79, 7.35, and 13.09 %. Furthermore, the annual logging residue availability with subsidy could meet 70 % of the annual woody biomass demand of the large-scale factory in Sano city, which is 100,000 tons.     

Effects of cooking on concentrations of polychlorinated dibenzo-p-dioxins and related compounds in fish and meat

We investigated the cooking-induced changes in concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) (dioxins) using mackerel and beef. The concentrations of dioxins (29 congeners) were determined by isomer specific analyses and were compared between uncooked and cooked samples. The cooking procedures examined in this study included grilling as a fillet, boiling as a fillet, and boiling as tsumire (small, hand-rolled balls) for mackerel and boiling as a slice, broiling as a slice, and broiling as a hamburger for beef. Three trials were carried out for each cooking method. Generally, concentrations of dioxins were reduced in every cooking trial. When nondetected congener concentrations were assumed to be half the limit of detection for mackerel, the maximum percentage reductions of total concentrations given as 2,3,7,8-tetraCDD equivalents (TEQ) were 31% in grilling as a slice, 14% in boiling as a slice, and 21% in boiling as tsumire under the conditions of this study. In contrast, for beef, the reductions were 42% in boiling as a slice, 42% in broiling as a slice, and 44% in broiling as a hamburger. These results suggest that ordinary cooking processes with heating undoubtedly reduce the dioxin content in animal products, and the reductions estimated should be considered when dioxin intake is evaluated using contamination data for individual food items.     

An H5N1 highly pathogenic avian influenza virus that invaded Japan through waterfowl migration

In 2010, an H5N1 highly pathogenic avian influenza virus (HPAIV) was isolated from feces of apparently healthy ducks migrating southward in Hokkaido, the northernmost prefecture of Japan. The H5N1 HPAIVs were subsequently detected in domestic and wild birds at multiple sites corresponding to the flyway of the waterfowl having stopovers in the Japanese archipelago. The Hokkaido isolate was genetically nearly identical to H5N1 HPAIVs isolated from swans in the spring of 2009 and 2010 in Mongolia, but less pathogenic in experimentally infected ducks than the 2009 Mongolian isolate. These findings suggest that H5N1 HPAIVs with relatively mild pathogenicity might be selected and harbored in the waterfowl population during the 2009-2010 migration seasons. Our data provide "early warning" signals for preparedness against the unprecedented situation in which the waterfowl reservoirs serve as perpetual sources and disseminators of HPAIVs.     

Reproductive phenotypes in mice with targeted disruption of the 20alpha-hydroxysteroid dehydrogenase gene

In the corpus luteum of rats and mice, 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD) catalyzes the conversion of progesterone to a biologically inactive metabolite, 20alpha-dihydroprogesterone (20alpha-OHP). The reduction of progesterone by 20alpha-HSD is believed to be important for functional luteolysis in these rodent species. In addition to the corpus luteum, expression of 20alpha-HSD has been demonstrated in tissues such as the placenta, endometrial epithelia, and fetal skin, although the roles it plays in the latter tissues remain to be determined. To determine the contribution of 20alpha-HSD to functional luteolysis and to the rodent reproductive system more generally, we generated a strain of mice with targeted disruption of the 20alpha-HSD gene. In the 20alpha-HSD-/- mice we obtained, which lacked the genomic region essential for catalytic reaction, neither 20alpha-HSD activity in the corpus luteum nor an increase in the serum concentrations of 20alpha-OHP during pseudopregnancy or pregnancy was detected. The durations of the estrous cycle, pseudopregnancy, and pregnancy were significantly prolonged in the 20alpha-HSD-/- mice, although the serum progesterone levels decreased to levels low enough for delivery of pups at term of pregnancy. In addition, the number of pups, especially live pups, was markedly decreased in the 20alpha-HSD-/- mice. These findings suggest that the role of 20alpha-HSD in functional luteolysis is relatively minor but that it is involved in the survival of newborn mice.     

Operational efficiencies and costs of an arm roll forwarder: A case study at Nasu in Tochigi Prefecture, Japan

We investigated a developed arm roll forwarder at Nasu in Tochigi Prefecture, Japan. An arm roll forwarder can only load a steel container that has been fully loaded with logs beforehand, and can later unload such a container. Such a forwarder can shorten the loading and unloading times and improve operational efficiency. We examined two operation systems with an arm roll forwarder and a forwarder. In the first system the loading was done with a grapple-loader. In the second system the loading was done with a processor. The loading times of an arm roll forwarder were significantly less than those of a forwarder. Because the optimal cycle times (excluding the waiting times for an arm roll forwarder) were significantly reduced, the costs of using an arm roll forwarder are lower, although the loading capacity was small and the hourly operation cost was high. The maximum operational efficiencies varied depending on forwarding distances. The second operation system with an arm roll forwarder exhibited the best operational efficiency within a 1,580-m forwarding distance, and beyond that distance it exhibited the highest operational efficiency when a forwarder was used. Similarly, the cost of operation of the system with an arm roll forwarder was the lowest within a 1,130-m forwarding distance, and beyond that distance the cost was the lowest when using the forwarder. Therefore, the arm roll forwarder is effective within a certain forwarding distance.     

Increased Cellular Distribution of Vimentin and Ret in the Cingulum of Rat Offspring After Developmental Exposure to Decabromodiphenyl Ether or 1,2,5,6,9,10-Hexabromocyclododecane

Abstract: To determine effects of developmental exposure to brominated flame retardants (BFRs), weak thyroid hormone disruptors, on white matter development, white matter-specific global gene expression analysis was performed using microdissection techniques and microarrays in male rats exposed maternally to decabromodiphenyl ether (DBDE), one of the representative BFRs, at 10, 100 or 1000 ppm. Based on previous gene expression profiles of developmental hypothyroidism and DBDE-exposed cases, vimentin⁺ immature astrocytes and ret proto-oncogene (Ret)⁺ oligodendrocytes were immunohistochemically examined after developmental exposure to representative BFRs, i.e., DBDE, 1,2,5,6,9,10-hexabromocyclododecane (HBCD; 100, 1000 or 10,000 ppm) and tetrabromobisphenol A (TBBPA; 100, 1000 or 10,000 ppm). Vimentin⁺ and Ret⁺ cell populations increased at ≥ 100 ppm and ≥ 10 ppm DBDE, respectively. Vimentin⁺ and Ret⁺ cells increased at ≥ 1000 ppm HBCD, with no effect of TBBPA. The highest dose of DBDE and HBCD revealed subtle fluctuations in serum thyroid-related hormone concentrations. Thus, DBDE and HBCD may exert direct effects on glial cell development at ≥ middle doses. At high doses, hypothyroidism may additionally be an inducing mechanism, although its contribution is rather minor.     

Gentian Kobu-sho-associated virus: a tentative, novel double-stranded RNA virus that is relevant to gentian Kobu-sho syndrome

A virus-like dsRNA of about 23 kbp was detected in gentian plants showing Kobu-sho syndrome including stunting, shortened internodes, and tumors on stems, nodes and roots. Nucleotide sequence analysis has suggested that this dsRNA is related to Pestivirus species but not to any other plant viruses. It was protected from externally added RNase, suggesting that the dsRNA is encapsidated. The dsRNA was co-extracted in a crude homogenate of glutaraldehyde-fixed tissue with the virus-like particles that have been associated previously with Kobu-sho syndrome in gentian (Usugi et al. Jpn J Phytopathol 76:21–24, 2010). The RNA sequence was detected in more than 99 % of Kobu-sho gentian individuals but in less than 20 % of apparently healthy gentian individuals from fields affected with Kobu-sho. Thus, we propose naming the virus Gentian Kobu-sho-associated virus.