Soil nitrogen dynamics of forest ecosystems under environmental changes     

Hideaki Shibata  Hiroto Toda  Yoshiyuki Inagaki  Ryunosuke Tateno  Keisuke Koba  Takeshi Tange 《Journal of Forest Research》2011,16(5):331-332

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Comparative Evaluation on Nitrogen Saturation of Forest Catchments in Japan and Northeastern United States     

Nobuhito Ohte  Myron J. Mitchell  Hideaki Shibata  Naoko Tokuchi  Hiroto Toda  Goro Iwatsubo 《Water, air, and soil pollution》2001,130(1-4):649-654

To analyze the differences in the status and processes of nitrogen saturation in Japan and northeastern United States, we examined the hydrobiogeochemistry of nitrogen of forested watersheds in these regions. Two distinct differences were found between watersheds in Japan compared with those in US. 1) In Japanese watersheds, marked decreases of NO₃ ^? concentration in surface waters during the summer growing season were not found and NO₃ ^? concentrations sometimes increased especially in the summer at nitrogen saturated sites. This contrast with watersheds in US where decreases in NO₃ ^? concentration during the summer are commonly observed except those watersheds in advanced stages of nitrogen saturation. These differences in NO₃ ^? concentration relationships can be attributed to climatic differences, with Japan having high precipitation and high discharge during the summer, while in many regions of North America lowest discharges are found in the summer. The climatic regime in Japan leads to high rates of mineralization and the rapid transport of NO₃ ^? to streams in summer. 2) Japanese watersheds, even those with high NO₃ ^? concentrations in surface waters, show little evidence of acidification. This is in contrast to sites in US where increased NO₃ ^? concentrations, especially during episodic events, result in surface water acidification.  相似文献   

Thermal conductivity of lunar and terrestrial igneous rocks in their melting range     

Murase T  McBirney AR 《Science (New York, N.Y.)》1970,170(3954):165-167

The thermal conductivity of a synthetic lunar rock in its melting range is about half that of a terrestrial basalt. The low conductivity and increased efficiency of insulating crusts on lunar lavas will enable flows to cover great distances without being quenched by high radiant heat losses from the surface. For a given rate of heat production, the thermal gradient of the moon would be significantly steeper than that of the earth.  相似文献   

Comparison of Bacterial Communities Associated with Microcrustaceans from the Floodwater of a Paddy Field Microcosm: Estimation Based on DGGE Pattern and Sequence Analyses     

Ainin Niswati  Jun Murase  Makoto Kimura 《Soil Science and Plant Nutrition》2005,51(2):281-290

Bacterial communities associated with five kinds of microcrustaceans ( Tanycypris sp., Moina sp., Mesocyclops sp., Cypretta sp. and Heterocypris sp.) from the floodwater of a paddy field microcosm were examined by the application of denaturing gradient gel electrophoresis (DGGE) to PCR-amplified 16S rDNA products with universal bacterial primers and by sequencing of characteristic DGGE bands. The number of DGGE bands of the associated bacteria was small, indicating the association of specific bacterial members with the microcrustaceans studied, among which Tanycypris sp. showed the smallest number of bands. Principal component analysis (PCA) demonstrated that the community structure of the associated bacteria could be divided into three groups: Podocopida ( Tanycypris sp., Cypretta sp. and Heterocypris sp.), Moina sp. and Mesocyclops sp., and further analysis separated Tanycypris sp. and Heterocypris sp. into different clusters. The duration of the incubation period affected the bacteria associated with Tanycypris sp., Moina sp. and Cypretta sp. only. Nearly all of the associated bacteria belonged to Gram-negative bacteria, especially the Cytophaga-Flavobacterium-Bacteroides (CFB) group. Closest relatives of the DGGE bands common to three Podocopida and Mesocyclops sp. belonged to an invertebrate endosymbiont.  相似文献   

Carbon cycling in rice field ecosystems in the context of input, decomposition and translocation of organic materials and the fates of their end products (CO₂ and CH₄)     

Makoto Kimura  Jun Murase 《Soil biology & biochemistry》2004,36(9):1399-1416

Rice fields are intensively managed, unique agroecosystems, where soil flooding is general performance for rice cultivation. Flooding the field results in reductive soil conditions, under which decomposition of organic materials proceeds during the period of rice cultivation. A large variety of organic materials are incorporated into rice soils according to field management. In this review, the kind and abundance of organic materials entering carbon cycling in the rice field ecosystem are evaluated first. Then, decomposition of plant residues and soil organic matter in rice fields is reviewed quantitatively. Decomposition of plant residues is shown to be the active process in carbon cycling in rice fields. Rice releases photosynthates into the rhizosphere (rhizodeposition), and they follow a different avenue of decomposition in soil from that of plant residues. Incorporation of rhizodeposition into microbial biomass and soil organic matter during the period of rice cultivation, and their fates after harvesting are evaluated quantitatively from ¹³C pulse labeled experiments. Percolating water transports inorganic and organic carbon from the plow layer to the subsoil layer. The amounts of their transport and accumulation in the subsoil layer are evaluated in relation to the amounts of soil organic C in the plow layer. Not only CO₂ but also CH₄ are produced in the decomposition process of organic materials in flooded rice fields. CH₄ evolution from rice fields is of global concern from the viewpoint of global warming. Origins of CH₄ evolved from rice fields are estimated first, followed by the fates of CH₄ in rice field ecosystems. Rhizodeposition is shown to be the main origin of CH₄ evolved from rice fields. Evolution to the atmosphere is not the sole pathway of CH₄ produced in rice fields. The amounts of CH₄ retained in soil, percolated to the subsoil layer and decomposed in soil are evaluated in the context of the amounts of CH₄ efflux. Thus, this review focuses on carbon cycling in the rice field ecosystem from the viewpoints of input, decomposition, and translocation of organic materials and the fates of their end products (CO₂ and CH₄).  相似文献   

Isolation and characterization of aminopeptidase (Jc-peptidase) from Japanese cedar pollen (Cryptomeria japonica)     

Noguchi Y  Nagata H  Koganei H  Kodera Y  Hiroto M  Nishimura H  Inada Y  Matsushima A 《Journal of agricultural and food chemistry》2002,50(12):3540-3543

An aminopeptidase, Jc-peptidase, was purified from Japanese cedar pollen by seven steps, including precipitation with ammonium sulfate, ion-exchange chromatography, gel filtration, hydrophobic interaction chromatography on phenyl-agarose, and high-performance liquid chromatography. Purified Jc-peptidease has a molecular weight of 42 kDa and hydrolyzes the synthetic substrates of L-phenylalanyl-4-methylcoumaryl-7-amide (Phe-MCA) with Km = 5 x 10(-5) M, Tyr-MCA with Km = 7 x 10(-4) M, Leu-MCA with Km = 1 x 10(-3) M, and Met-MCA with Km = 1 x 10(-3) M. Other MCA analogues such as Arg-MCA or Glu-MCA failed to serve as its substrates. The activity was inhibited in the presence of phebestin, [(2S,3R)-3-amino-2-hydroxy-4-phenylbutanoyl-L-valyl]-L-phenylalanine, with Ki = 4.7 x 10(-5) M, or bestatin, [(2S,3R)-3-amino-2-hydroxy-4-phenylbutanoyl]-L-leucine, with Ki = 1.1 x 10(-4) M. According to amino acid sequence analysis, the N-terminal amino group seems to be blocked. The physiological function of the aminopeptidase (Jc-peptidase) has not been clarified in vivo.  相似文献   

Partial laryngectomy     

K Hiroto 《Science (New York, N.Y.)》1970,170(955):Suppl:1209-Suppl:1212

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Male Pseudohermaphroditism in a raccoon dog (Nyctereutes procynoides)     

Weng Q  Murase T  Asano M  Tsubota T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(6):603-605

A wild raccoon dog (Nyctereutes procynoides) which died due to a traffic accident on 18 October 2001, and was determined to be 4.5 years old, was examined. Visual appearance of the external genitalia in this animal showed to be female with a large penis-like clitoris protruding from the vulvar juncture. Visual examination of the internal genitalia revealed that the animal possessed both testes and uterus. Histological appearance of the removed gonads showed only Sertoli cells but no spermatogenesis. Using polymerase chain reaction with skin biopsy directed against the sex-determining region on the Y chromosome (SRY) gene, the genomic SRY gene was expressed as a single band and sequenced. Based on these findings, this raccoon dog was diagnosed as male pseudohermaphrodite.  相似文献   

Detection of the esp gene in high-level gentamicin resistant Enterococcus faecalis strains from pet animals in Japan   总被引：1，自引：0，他引：1  

Harada T  Tsuji N  Otsuki K  Murase T 《Veterinary microbiology》2005,106(1-2):139-143

We investigated the prevalence of the esp gene and the susceptibility to gentamicin in Enterococcus faecalis and E. faecium strains obtained from pet animals. Nine of 30 E. faecalis and 2 of 38 E. faecium strains from the pet animals had the esp gene. Three esp-positive E. faecalis strains, which were isolated from two dogs and a cat, showed gentamicin MICs of > or =256 microg/ml and harbored the high-level gentamicin resistance (HLGR) gene, aac(6')-Ie-aph(2')-Ia. Of the nine esp-positive E. faecalis strains, five, including the three strains with the HLGR gene, were closely related by numerical analysis of PFGE patterns. Longitudinal investigation needs to elucidate whether the HLGR gene was incorporated into a subpopulation of the esp-positive E. faecalis.  相似文献   

Electroejaculation and semen cryopreservation of free-ranging Japanese black bears (Ursus thibetanus japonicus)     

Okano T  Murase T  Tsubota T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(11):1371-1376

The Japanese black bear (Ursus thibetanus japonicus) is endangered for extinction in some areas of Japan, and semen collection and cryopreservation are an important means to preserve genetic resources. The aim of this study was to characterize and cryopreserve semen of free-ranging Japanese black bears. Semen was collected by electroejaculation procedure from 4 free-ranging Japanese black bears at the capture point in the field. Ejaculates containing motile sperm were recovered from all of the animals and ejaculate volume, total sperm count, % motility (percentage of motile spermatozoa), % viability (percentage of spermatozoa that excluded eosin) and % abnormal morphology (range (mean)) were 0.65-2.20 (1.51) ml, 99-1082 (490) x 10(6), 5-100 (31), 42-97 (66) and 20-87 (53), respectively. Three of the 4 ejaculates were diluted with an egg yolk-TRIS-citrate-glucose extender and cryopreserved in liquid nitrogen. Motile spermatozoa were observed after freezing and thawing in all cases. This study showed that electroejaculation would be a useful method for collecting semen from free-ranging Japanese black bears and that at least motile spermatozoa would be obtained by freezing the thus collected electroejaculates.  相似文献