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Soil microbial immobilization and plant uptake of N were evaluated for three forest types in Kochi, Shikoku district. During 196-d laboratory incubation, soil NO3 -N production in the Hinoki cypress forest was negligible for the initial 40 d and then rapidly increased, whereas NO3 -N production was rapid from the beginning in Japanese cedar and deciduous hardwood forests. Microbial immobilization of the labeled 15 N decreased in the order of NH4 -N>glycine-N>NO3 -N. The 15 N immobilization was higher for soil in the Hinoki cypress forest than other two soils. The delayed NO3 -N production in the Hinoki cypress forest was likely related with low availability of NH4 -N due to NH4 -N immobilization and substantial NO3 -N immobilization. In the field experiment, 15 N uptake by roots decreased in the order of NH4 -N>NO3 -N>glycine-N. The absorption of the labeled 13 C suggested direct uptake of organic N. The preference of N forms by root uptake was not different among forest types. Trees in three forest types can absorb inorganic and organic forms of N, suggesting trees absorb the N form that is the most abundant in the soil. 相似文献
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Munang'andu HM Munag'andu HM Siamudaala VM Nambota A Bwalya JM Munyeme M Mweene AS Takada A Kida H 《The Japanese journal of veterinary research》2006,54(1):3-13
Eco-tourism depending on wildlife is becoming increasingly profitable and landowners are beginning to favor game farming and ecotourism. In these areas, large-scale translocation of wildlife involves a diversity of species and large populations. The African buffalo (Syncerus caffer) is one of the major tourist attractions in Zambia. It accounts for 8.7% and 12.4% of the total animal species hunted in the Game Management Areas and the total hunting revenue earned in Zambia, respectively. It is ecologically an important animal species essential for the purpose of habitat control and facilitating the provision of suitable grazing pastures. However, the rearing of the African buffalo on game ranches has been hampered by its carrier state of the Southern Africa Terroritory (SAT) serotypes of foot and mouth disease virus (FMD). The African buffalo is also known to be a carrier of Theileria parva lawrencei, the causative agent of corridor disease (CD) that continues to have devastating effects on the livestock industry in Zambia. In addition, the importation of buffaloes from countries with populations endemic to bovine tuberculosis is highly restricted. Veterinary regulations in Zambia, strongly advocate against the translocation of buffaloes from protected areas to private ranches for disease control purposes thereby mounting a considerable constraint on the economic and ecological viability of the industry. It is hoped that this review will motivate the relevant government authorities in exploiting ways in which this animal species play a central role in eco-tourism. 相似文献
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Shimotori Koichi Yamamoto Haruki Imai Akio Kohzu Ayato Okamoto Takahiro 《Journal of Soils and Sediments》2021,21(2):1222-1231
Journal of Soils and Sediments - Sediment oxygen demand (SOD) measurement currently requires a long preparation time and bulky experimental equipment, which represent major obstacles to conducting... 相似文献
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Ayato Kohzu Toshihiro Miyajima Takashi Watanabe Eitaro Wada 《Soil biology & biochemistry》2005,37(9):1598-1607
Factors that affect the δ13C values of fungi need to be analyzed for the progress of isotope-based studies of food-chain or organic matter dynamics in soils. To analyze the factors that control δ13C values of the fungal body, basidiomycete and ascomycete species were grown on a beechwood substrate (six species) and in glucose medium (nine species), and the δ13C value of produced fungal body was compared to that of the carbon source. The 13C enrichment (Δδ13C) in the fungal aggregates compared to the decomposed wood varied from 1.2 to 6.3‰ among six species. In the glucose substrate experiment, the degree of 13C enrichment in the hyphal mat was relatively small and varied from −0.1 to 2.8‰ among nine basidiomycetes species depending on their growth stage. Calculated δ13C values of the respired CO2 were lower than those of the hyphal mat, organic metabolites and the glucose used. The degree of 13C enrichment was affected by fungal species, substrate and growth stage. Fungal internal metabolic processes are the plausible mechanism for the observed isotopic discrimination between fungal bodies and substrates. Especially, dark fixation of ambient CO2 and kinetic isotope fractionation during assimilation and dissimilation reactions could well explain Δδ13C dynamics in our experiments. Through the analysis of field Δδ13C, we could know undisturbed fungal status about starvation, aeration and type of decomposition. 相似文献
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Kajihara M Matsuno K Simulundu E Muramatsu M Noyori O Manzoor R Nakayama E Igarashi M Tomabechi D Yoshida R Okamatsu M Sakoda Y Ito K Kida H Takada A 《The Japanese journal of veterinary research》2011,59(2-3):89-100
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. 相似文献
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Ayato Kohzu Takahiro Tateishi Akiyoshi Yamada Keisuke Koba Eitaro Wada 《Soil Science and Plant Nutrition》2013,59(3):733-739
The 15N natural abundance in Pinus densiflora Sieb. et Zucco that had been inoculated and not inoculated with ectomycorrhizal fungi (Suillus granulatus (L.:Fr.) O. Kuntze) was compared. The inoculated pine needles showed a lower δ15N value, while the uninoculated ones showed a higher δ15N value. Higher δ15N values in the mycelial mat of the ectomycorrhizal fungi compared to those of the inoculated pine needles were also observed. These facts indicate that nitrogen isotope fractionation occurred during the nitrogen transport from mycorrhizal fungi to the host plants. 相似文献
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Seroepidemiological evidence of avian H4, H5, and H9 influenza A virus transmission to pigs in southeastern China 总被引：1，自引：0，他引：1
Pig serum samples collected in southeastern China were examined for antibodies to influenza A viruses. Since the hemagglutination inhibition (HI) test does not accurately detect antibodies to the hemagglutinins (HAs) of "avian" influenza viruses, we utilized the neutralization (NT) test to detect subtype-specific antibodies to the HA of avian viruses in pig sera. Neutralizing antibodies to H1, H3, H4, and H5 influenza viruses were detected in the serum samples collected in 1977-1982 and 1998, suggesting that pigs in China have been sporadically infected with avian H4 and H5 viruses in addition to swine and human H1 and H3 viruses. Antibodies to H9 virus, on the other hand, were found only in the sera collected in 1998, not in those collected in 1977-1982, correlating with the recent spread in poultry and subsequent isolation of H9N2 viruses from pigs and humans in 1998. The present results indicate that avian influenza viruses have been transmitted to pig populations in southeastern China. 相似文献
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Neurotropism of the 1997 Hong Kong H5N1 influenza virus in mice 总被引：12，自引：0，他引：12
Tanaka H Park CH Ninomiya A Ozaki H Takada A Umemura T Kida H 《Veterinary microbiology》2003,95(1-2):1-13
The direct transmission of H5N1 influenza A viruses from chickens to humans in Hong Kong in 1997 emphasized the need to have information on the pathogenesis of avian influenza virus infection in mammals. H5N1 influenza viruses isolated from patients during the incident killed experimentally infected mice. The principal lesions of the mice were broncho-interstitial pneumonia and nonsuppurative encephalitis. Infectious viruses and/or viral antigens were detected in the brain as well as in the trigeminal and vagal ganglia but not in the blood of the mice. These findings suggest that the virus reached the brain through the vagus and/or trigeminal nerves following replication in the respiratory mucosa. The results imply that neurotropism of the H5N1 virus in mice is a novel characteristic in the pathogenesis of infection by human influenza virus isolates. 相似文献