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排序方式: 共有1363条查询结果,搜索用时 15 毫秒
941.
We studied the effects of extending the rotation period (long-rotation) and related ecological variables on the biodiversity of six beetle families in larch (Larix kaempferi) plantations. Beetle diversity in the forest understory and the canopy of long-rotation and middle-aged plantations was compared. The relationships between the species richness of each beetle family and 24 ecological variables were identified. We found that beetle diversity tended to increase with long-rotation and responded differently to the ecological variables in two woodland strata (understory and canopy); e.g., an increase in phytophagies occurred in the canopy. Among the 24 measured ecological variables, the species richness of naturally regenerated mature trees, their abundance, and the quality and quantity of coarse woody material (CWM) had the strongest influences on beetle diversity. The former two variables increased with long-rotation; however, most variables related to CWM did not increase because thinned trees were left in middle-aged plantations as fallen logs. Therefore, the occurrence of naturally regenerated native trees that had grown sufficiently tall to reach canopy height in long-rotation plantations underpinned the improved biodiversity in larch plantations, contributing to native beetle species richness in these woodlands. Long-rotation makes plantations more heterogeneous, particularly in the canopy, and promotes greater native beetle diversity. 相似文献
942.
943.
Noritoshi KAWATE Makoto TSUJI Shingo HATOYA Toshio INABA Hiromichi TAMADA 《Animal Science Journal》2011,82(3):390-395
Differences in the distribution of single nucleotide polymorphisms (SNPs) and haplotypes in the estrogen receptor α gene (ESR1) were examined in Miniature Dachshunds (n = 48), Chihuahuas (n = 20) and Toy Poodles (n = 18). Five DNA fragments located in the 40‐kb region at the 3′ end of ESR1 were amplified by polymerase chain reaction and were directly sequenced. We compared allele, genotype and estimated haplotype frequencies at each SNP in the 3′ end of ESR1 for these three breeds of small dog. The frequency of the major allele and the genotype frequency of the major allele homozygotes, were significantly higher in Toy Poodles for five SNPs (SNP #5, #14–17) than in Miniature Dachshunds, and significantly higher in Toy Poodles than Chihuahuas for three SNPs (SNP #15–17). A common haplotype block was identified in an approximately 20‐kb region encompassing four SNPs (SNPs # 14–17). The frequencies of the most abundant estimated haplotype (GTTG) and GTTG homozygotes were significantly higher in Toy Poodles than in the other two breeds. These results imply that homozygosity for the allele, genotype and haplotype distribution within the block at the 3′ end of ESR1 is greater in Toy Poodles than in Miniature Dachshunds and Chihuahuas. 相似文献
944.
Kobayashi J Mori Y Okamoto K Akiyama R Ueno M Kitamori T Kobayashi S 《Science (New York, N.Y.)》2004,304(5675):1305-1308
We have developed an efficient system for triphase reactions using a microchannel reactor. Using this system, we conducted hydrogenation reactions that proceeded smoothly to afford the desired products quantitatively within 2 minutes for a variety of substrates. The system could also be applied to deprotection reactions. We could achieve an effective interaction between hydrogen, substrates, and a palladium catalyst using extremely large interfacial areas and the short path required for molecular diffusion in the very narrow channel space. This concept could be extended to other multiphase reactions that use gas-phase reagents such as oxygen and carbon dioxide. 相似文献
945.
In normal albino rats with a 4-day estrous cycle, the activity of ovarian ornithine decarboxylase undergoes a transitory rise on the evening of proestrus and only at that time. The response could be elicited by the administration of either luteinizing hormone or human chorionic gonadotrophin. When antiserum to luteinizing hormone was injected at 2 p.m. on the day of proestrus, the induction of ornithine decarboxylase was blocked, an indication that the enzyme is under luteinizing hormone control. The strategic positioning of the induction of ornithine decarboxylase between the normal release of luteinizing hormone and ovulation impties that putrescine is associated with the ovulatory process, and opens a new avenue of research on the control of ovulation. 相似文献
946.
Thin-film transistor fabricated in single-crystalline transparent oxide semiconductor 总被引:1,自引:0,他引:1
Nomura K Ohta H Ueda K Kamiya T Hirano M Hosono H 《Science (New York, N.Y.)》2003,300(5623):1269-1272
We report the fabrication of transparent field-effect transistors using a single-crystalline thin-film transparent oxide semiconductor, InGaO3(ZnO)5, as an electron channel and amorphous hafnium oxide as a gate insulator. The device exhibits an on-to-off current ratio of approximately 106 and a field-effect mobility of approximately 80 square centimeters per volt per second at room temperature, with operation insensitive to visible light irradiation. The result provides a step toward the realization of transparent electronics for next-generation optoelectronics. 相似文献
947.
Interaction of the IL-2 receptor with the src-family kinase p56lck: identification of novel intermolecular association 总被引:104,自引:0,他引:104
M Hatakeyama T Kono N Kobayashi A Kawahara S D Levin R M Perlmutter T Taniguchi 《Science (New York, N.Y.)》1991,252(5012):1523-1528
In the interleukin-2 (IL-2) system, intracellular signal transduction is triggered by the beta chain of the IL-2 receptor (IL-2R beta); however, the responsible signaling mechanism remains unidentified. Evidence for the formation of a stable complex of IL-2R beta and the lymphocyte-specific protein tyrosine kinase p56lck is presented. Specific association sites were identified in the tyrosine kinase catalytic domain of p56lck and in the cytoplasmic domain of IL-2R beta. As a result of interaction, IL-2R beta became phosphorylated in vitro by p56lck. Treatment of T lymphocytes with IL-2 promotes p56lck kinase activity. These data suggest the participation of p56lck as a critical signaling molecule downstream of IL-2R via a novel interaction. 相似文献
948.
Accumulation of phosphorylated repressor for gibberellin signaling in an F-box mutant 总被引:4,自引:0,他引:4
Sasaki A Itoh H Gomi K Ueguchi-Tanaka M Ishiyama K Kobayashi M Jeong DH An G Kitano H Ashikari M Matsuoka M 《Science (New York, N.Y.)》2003,299(5614):1896-1898
Gibberellin (GA) regulates growth and development in plants. We isolated and characterized a rice GA-insensitive dwarf mutant, gid2. The GID2 gene encodes a putative F-box protein, which interacted with the rice Skp1 homolog in a yeast two-hybrid assay. In gid2, a repressor for GA signaling, SLR1, was highly accumulated in a phosphorylated form and GA increased its concentration, whereas SLR1 was rapidly degraded by GA through ubiquitination in the wild type. We conclude that GID2 is a positive regulator of GA signaling and that regulated degradation of SLR1 is initiated through GA-dependent phosphorylation and finalized by an SCF(GID2)-proteasome pathway. 相似文献
949.
Luteophanol D (1), a new polyhydroxyl linear carbon-chain metabolite, has been isolated from the cultured marine dinoflagellate Amphidinium sp., which was isolated from Okinawan marine acoel flatworm Pseudaphanostoma luteocoloris. The structure of 1 was elucidated by detailed analyses of 2D NMR spectra. Luteophanol D (1) possesses two tetrahydropyran rings and twenty-three hydroxyl groups on C63-linear aliphatic chain with one exo-methylene and two methyl branches. 相似文献
950.
Hidetoshi MORITA Akiyo NAKANO Mitsuharu SHIMAZU Hidehiro TOH Fumihiko NAKAJIMA Masahiro NAGAYAMA Shin HISAMATSU Yukio KATO Misako TAKAGI Hideto TAKAMI Hiroaki AKITA Minoru MATSUMOTO Toshio MASAOKA Masaru MURAKAMI 《Animal Science Journal》2009,80(3):339-346
To detect the predominant lactobacilli in the intestinal flora of healthy thoroughbreds, we isolated lactobacilli from the feces of nine thoroughbreds (five males and four females; 0–15-year-old). The isolated lactobacilli comprise 17 species (37 strains), and they were classified into five groups: Lactobacillus salivarius (6 species), L. reuteri (6 species), Lactobacillus delbrueckii (3 species), L. buchneri (1 species) and L. vitulinus (1 species). On the basis of 16S rRNA gene sequences, we identified 3 other phylogenetic relatives belonging to the genus Lactobacillus . These results suggest that the intestinal flora of thoroughbreds may comprise many species of the genus Lactobacillus . Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analyses of the 340-bp fragments of the 16S rRNA genes from the same nine fecal samples showed that L. hayakitensis , L. equigenerosi and L. equi are contained in all the samples, suggesting that these species are predominant lactobacilli in the intestinal flora of thoroughbreds. 相似文献