排序方式： 共有9条查询结果，搜索用时 31 毫秒
1
1.
Fukuzawa R Fukuzawa K Abe H Nagai T Kameyama K 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2004,33(1):39-42
Abstract: A male African pygmy hedgehog ( Atelerix albiventris ), estimated to be 3 years old, presented with exophthalmos and fixed abduction of the right eye. Radiographic examination revealed a retrobulbar tumor in the right orbital cavity. The mass was surgically resected but recurred 3 months later and the hedgehog died. There was no gross or microscopic evidence of salivary or lacrimal gland involvement of the tumor at surgery or at necropsy. The histopathologic, immunohistochemical, and ultrastructural findings were those of acinic cell carcinoma, the origin of which was unknown. This is the first known case of acinic cell carcinoma in an African hedgehog. 相似文献
2.
Merchant SS Prochnik SE Vallon O Harris EH Karpowicz SJ Witman GB Terry A Salamov A Fritz-Laylin LK Maréchal-Drouard L Marshall WF Qu LH Nelson DR Sanderfoot AA Spalding MH Kapitonov VV Ren Q Ferris P Lindquist E Shapiro H Lucas SM Grimwood J Schmutz J Cardol P Cerutti H Chanfreau G Chen CL Cognat V Croft MT Dent R Dutcher S Fernández E Fukuzawa H González-Ballester D González-Halphen D Hallmann A Hanikenne M Hippler M Inwood W Jabbari K Kalanon M Kuras R Lefebvre PA Lemaire SD Lobanov AV 《Science (New York, N.Y.)》2007,318(5848):245-250
Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the approximately 120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella. 相似文献
3.
We investigated the dynamics of litterfall and litter decomposition of Sasa dwarf bamboo (Sasa senanensis) and trees to clarify the characteristics of organic matter and nitrogen cycling between plant and soil in a natural cool-temperate mixed forest ecosystem dominated by an understory vegetation of Sasa. Mean annual Sasa litterfall over the 3-year study period was 164 g m?2 year?1, which accounted for approximately 29% of total litterfall. Litter decomposition of Sasa leaf and Sasa culm was significantly slower than that of tree leaf during first and second years. The slow decomposition rates of both Sasa litter types were caused by a significantly higher silicate than in tree leaf. Nitrogen concentration in litter increased as decomposition progressed, especially in Sasa leaf and tree leaf. As a result of the slow decomposition of both Sasa litter types, 111 and 73% of nitrogen to the initial amounts were retained in Sasa leaf and Sasa culm after 3 years, respectively. The amounts of retained nitrogen in Sasa leaf, Sasa culm, and tree leaf after 3 years were 1.29, 0.47, and 3.92 g N m?2, respectively, indicating that the differences of litter decomposition rates among the litter types influence on the nitrogen cycling in forest ecosystem through the differences of the nitrogen release from litter. 相似文献
4.
Kentaro Hayashi Kentaro Takagi Izumi Noguchi Karibu Fukuzawa Hiroyuki Takahashi Tatsuya Fukazawa Hideaki Shibata Yasumi Fujinuma 《Water, air, and soil pollution》2009,200(1-4):33-46
The present study aimed to elucidate the atmosphere–forest exchange of ammoniacal nitrogen (NHX-N) at a young larch ecosystem. NHX-N exchanges were measured at a remote site in northernmost Japan where 4-year-old larches were growing after a pristine forest had been clear-cut and subsequent dense dwarf bamboo (Sasa) had been strip-cut. The site was a clean area for atmospheric ammonia with mean concentrations of 0.38 and 0.11 μg N m?3 in snowless and snow seasons, respectively. However, there was a general net emission of NHX-N. The annual estimated emission of NHX-N of 4.8 kg N ha?1 year?1 exceeded the annual wet deposition of 2.4 kg N ha?1 year?1, but the weekly exchange fluxes may have been underestimated by 28–60%. The main cause of the ammonia loss from the young larch ecosystem was probably enhanced nitrogen supply stimulated by the cutting of the pristine forest and Sasa, in particular, the Sasa. 相似文献
5.
New Forests - The use of heavy forestry machines for clear-cutting and site preparation causes soil compaction, which can decrease forest productivity. This process becomes complicated in forests... 相似文献
6.
Megumi Fukuzawa Naomi Hayashi 《Journal of Veterinary Behavior: Clinical Applications and Research》2013,8(4):221-224
Effective dog training involves reinforcement of the dog's correct actions in response to specific cues given by the trainer. Food is usually selected as the primary reinforcer (reward), although this selection does not necessarily account for the learning preferences of individual dogs. We evaluated the relationship between reward and learning efficiency. Fifteen dogs were allocated to 3 different reward groups (food, stroking, and praise) and trained by an identical process. The food reward was the only one that shortened the time taken for the response to the command to be completed. However, this difference occurred only in the early training stages and not later in the training process. 相似文献
7.
Hideaki Shibata Rieko Urakawa Hiroto Toda Yoshiyuki Inagaki Ryunosuke Tateno Keisuke Koba Asami Nakanishi Karibu Fukuzawa Ayaka Yamasaki 《Journal of Forest Research》2011,16(5):374-385
Net nitrogen transformation was investigated under different climate conditions by soil transplantation and in situ incubation
of forest surface soils using the resin-core method. Selected conditions were considered to reflect those of the natural climate
gradient in the Japanese archipelago. Study sites were established in natural forests in northern Hokkaido (Uryu), northern
Kanto (Kusaki), central Kinki (Kamigamo), and southern Kyushu (Takakuma), representing the northernmost to the southernmost
island regions of Japan. Field experiments comparing soils incubated at “native” and “transplanted” sites were conducted from
June 2008 to May 2009. Net production, accumulation, and leaching of soil ammonium (NH4
+) and nitrate (NO3
−) were measured at each of the sites during the growing season (June–October), the dormant season (November–May), and throughout
the year. Net nitrate production was highest in Kusaki soil, especially during the growing season, whereas net ammonium production
was highest in Uryu soil, the coldest site, especially during the dormant season. Net nitrate production increased significantly
in soils transplanted to a warmer climate during the growing season. However, net ammonium production increased in soils transplanted
to colder climates during the dormant season. These findings indicate that, with the exception of the infertile soil samples
from Kamigamo, the range of natural climates in Japan has a significant effect on nitrogen availability in surface soil. In
addition, the original characteristics of the nitrogen cycle of the surface soil from each native site were retained, even
when marked changes in soil temperature (approximately 8°C) occurred after transplantation. 相似文献
8.
Sakaue M Ishimura R Kurosawa S Fukuzawa NH Kurohmaru M Hayashi Y Tohyama C Ohsako S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(2):107-113
ABSTRACT. To study the role of estrogen in the testes, testosterone and testicular steroidogenic enzyme mRNA levels were investigated in male Sprague-Dawley rats 24 hr after intramuscular administration of a single dose of estradiol-3-benzoate (EB). EB administration resulted in a greater decrease in intra-testicular and serum testosterone in 10-week-old rats than in 3- or 5-week-old rats. A dose of 2 microg EB/kg had the lowest observed effect. The level of serum luteinizing hormone (LH) was unchanged at any dose. Semiquantitative RT-PCR analysis revealed that, of the four major testicular steroidogenic enzymes, mRNA levels of cytochrome P450 side-chain cleavage and 17beta-hydroxysteroid dehydrogenase type-III were significantly reduced, and mRNA levels of cytochrome P450 17alpha-hydroxylase/ C17-20 lyase (P450c17) were reduced severely and significantly, by EB administration. However, the level of 3beta-hydroxysteroid dehydrogenase type-I mRNA was not changed. In addition, the P450c17 mRNA level in EB-treated rats was much lower than that in the testes of hypophysectomized rats, with the level in the latter being equal to that in control rats. LH is secreted into blood periodically, the effects of estrogen on the LH secretion pattern of the pituitary gland, for example, in frequency and amplitude of LH pulse, were difficult to detect with the methods of the present study. The results indicated, at least, that EB administration down-regulates P450c17 gene expression predominantly, resulting in the inhibition of testosterone production. From the differences in the steroidogenic enzyme expressions between hypophysectomized and EB-treated rats, it was suggested that EB acts on the testis directly or indirectly though not via alteration of LH secretion and induces reduction of P450c17 mRNA level. 相似文献
9.
Ge M Chen Z Onishi HR Kohler J Silver LL Kerns R Fukuzawa S Thompson C Kahne D 《Science (New York, N.Y.)》1999,284(5413):507-511
Vancomycin is an important drug for the treatment of Gram-positive bacterial infections. Resistance to vancomycin has begun to appear, posing a serious public health threat. Vancomycin analogs containing modified carbohydrates are very active against resistant microorganisms. Results presented here show that these carbohydrate derivatives operate by a different mechanism than vancomycin; moreover, peptide binding is not required for activity. It is proposed that carbohydrate-modified vancomycin compounds are effective against resistant bacteria because they interact directly with bacterial proteins involved in the transglycosylation step of cell wall biosynthesis. These results suggest new strategies for designing glycopeptide antibiotics that overcome bacterial resistance. 相似文献
1