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排序方式: 共有141条查询结果,搜索用时 15 毫秒
1.
Yoshiki Matsushita Shusuke Machida Haruyuki Kanehiro Fumio Nakamura Naoto Honda 《Fisheries Science》2008,74(2):230-235
ABSTRACT: A small number of fishers in Chiba Prefecture of eastern Japan use cotton gill nets to catch Japanese spiny lobster Panulirus japonicus. To examine the advantages of cotton gill nets, we analyzed changes in mesh breaking load of a new cotton gill net used in a fishing operation. A new cotton gill net was also soaked in a seawater tank to simulate ghost fishing conditions. The average mesh breaking load of new cotton mesh was 50.3 N. This value decreased to 19.0 N after 38 days (∼912 h), and after 82 days (∼1968 h) the mesh could be easily torn (breaking load 0.07 N). Under fishing conditions, the cumulative soak time was only 744.4 h over 19 months. The average breaking load at the end of this period was 43.1 N, a strength 86% that of the presoaked mesh. The mesh breaking load of a cotton gill net continuously soaked for 744.4 h was 26.1 N, as estimated from tank experiment data. Thus, a cotton gill net maintains reasonable strength under typical use conditions, but will degrade if lost at sea. 相似文献
2.
Katsushige Shiraki Yoshiki Shinomiya Hirofumi Shibano 《Journal of Forest Research》2006,11(6):439-447
Numerical experiments of soil water movement and bedrock infiltration based on a simplified simulation method were conducted
to analyze watershed-scale rainfall-runoff processes. To verify the model accuracy, it was applied to a Minamitani watershed
(0.45 ha). The simulation was performed with 2.5-m space grids horizontally and five cells vertically. Results of long-term
calculation of this model proved that this simulation model is robust and demonstrated good computational water mass conservation.
Calculation results showed the best agreement with observed hydrographs and the number of groundwater levels simultaneously
when laboratory-tested soil hydraulic characteristics for topsoil were used and infiltration into bedrock was included in
numerical calculations. Numerical experiments show that bedrock infiltration generated a stable base flow and suppressed the
secondary discharge peak. The reproducibility achieved by observed soil hydraulic characteristics with the assumption of bedrock
flow demonstrates the effectiveness of the simulation model used in this article for analyses of watershed-scale soil water
movements. 相似文献
3.
Background
The etiology of canine chronic bronchitis (CB) is not completely understood, although exposure to environmental tobacco smoke (ETS) affects the airway inflammatory responses in some dogs with CB. The mechanism by which this occurs is unknown.Findings
We investigated the concentrations and methylation rates of free-floating DNA fragments in bronchoalveolar lavage fluid (BALF) from dogs with chronic bronchitis. Based on serum cotinine levels, dogs with CB were divided into 2 groups: dogs that either had or had not been exposed to ETS. Our results demonstrated that the total nucleated cell and macrophage numbers increased in BALF of ETS-exposed dogs with CB. There were no significant differences in DNA concentrations and methylation rates in BALF between the 2 groups. However, 3 out of 8 dogs exposed to ETS had high DNA methylation rates in their BALF samples.Conclusion
Our results suggest that ETS exposure leads to epigenetic modifications of cellular components in BALF in dogs diagnosed with CB. 相似文献4.
Yoshiki YAMAYA Toshihiro WATARI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(4):421-425
Canine chronic rhinitis (CR) and bronchitis (CB) are suspected to be allergic diseases.
The present study tested whether dogs diagnosed with CR or CB present an atopic
predisposition based on the ratio of CC chemokine receptor 4 (CCR4)-positive cells among
peripheral blood CD4-positive cells (CCR4/CD4) and the serum levels of allergen-specific
IgE antibodies. We found that most dogs with CR and CB have a possibility of atopic
predisposition, and macrolide therapy constitutes an alternative to corticosteroid therapy
in controlling the clinical signs. 相似文献
5.
6.
Yoshiki SHIRAKATA Yuuki HIRADATE Hiroki INOUE Eimei SATO Kentaro TANEMURA 《The Journal of reproduction and development》2014,60(5):383-387
The core histone is composed of four proteins (H2A, H2B, H3 and H4). Investigation of the modification patterns of histones
is critical to understanding their roles in biological processes. Although histone modification is observed in multiple cells
and tissues, little is known about its function in spermatogenesis. We focused on the modification patterns of histone H4
during murine spermatogenesis. We demonstrated that the individual N-terminal sites of H4 show different modification
patterns during the differentiation of male germ cells. The methylation pattern varied depending on the residues that were
mono-, di-, or tri-methylated. All the H4 modifications were high during the meiotic prophase, suggesting that histone H4
modification plays an important role during this stage of spermatogenesis. Elongating spermatids showed increased acetylation
of histone H4, which may be associated with a histone-to-protamine substitution. Our results provide further insight into the
specific relationship between histone H4 modification and gene expression during spermatogenesis, which could help to
elucidate the epigenetic disorders underlying male infertility. 相似文献
7.
T. Matsumoto Y. Nagashima K. Takayama K. Shimakura K. Shiomi 《Fish physiology and biochemistry》2005,31(1):95-100
In vitro accumulation of tetrodotoxin (TTX) and paralytic shellfish toxin (PST) in tiger puffer fish Takifugu rubripes was investigated using liver tissue slices. When T. rubripes liver slices were incubated with Leibovitz’s L-15 medium containing 0.13 mM TTX at 20 °C in air with saturated humidity, they accumulated 21.5 ± 7.3 μg TTX g?1 liver after the incubation for 12 h and increased to 55.3 ± 8.2 μg TTX g?1 liver at 48 h. In the incubation of T. rubripes liver slices with 0.13 mM PST-containing medium, PST was detected 6.3 ± 0.9 μg g?1 liver at 12 h and reached a plateau thereafter. These results reveal the difference between TTX and PST in accumulation in T. rubripes liver tissue slices. To examine the variation in PST accumulation among fish species, the liver tissue slices from tiger puffer fish T. rubripes, parrot-bass Oplegnathus fasciatus and green ling Hexagrammos otakii were incubated at a concentration of 0.027 mM PST. The toxin contents of 3.0 μg g?1 liver were observed at 8 h regardless of fish species but were not increased subsequently, showing no variety among these three species as to accumulation patterns of PST. It is noted that the tiger puffer fish T. rubripes liver specifically accumulate TTX in preference to PST. 相似文献
8.
The recent discovery of mammalian bitter, sweet, and umami taste receptors indicates how the different taste qualities are encoded at the periphery. However, taste representations in the brain remain elusive. We used a genetic approach to visualize the neuronal circuitries of bitter and sweet tastes in mice to gain insight into how taste recognition is accomplished in the brain. By selectively expressing a transsynaptic tracer in either bitter- or sweet and/or umami-responsive taste receptor cells, and by comparing the locations of the tracer-labeled neurons in the brain, our data revealed the potential neuronal bases that underlie discrimination of bitter versus sweet. 相似文献
9.
A protein that binds to a cis-acting element of wheat histone genes has a leucine zipper motif 总被引:34,自引:0,他引:34
T Tabata H Takase S Takayama K Mikami A Nakatsuka T Kawata T Nakayama M Iwabuchi 《Science (New York, N.Y.)》1989,245(4921):965-967
10.
Sex determination in the Drosophila germ line is regulated by both the sex of the surrounding soma and cell-autonomous cues. How primordial germ cells (PGCs) initiate sexual development via cell-autonomous mechanisms is unclear. Here, we demonstrate that, in Drosophila, the Sex lethal (Sxl) gene acts autonomously in PGCs to induce female development. Sxl is transiently expressed in PGCs during their migration to the gonads; this expression, which was detected only in XX PGCs, is necessary for PGCs to assume a female fate. Ectopic expression of Sxl in XY PGCs was sufficient to induce them to enter oogenesis and produce functional eggs when transplanted into an XX host. Our data provide powerful evidence that Sxl initiates female germline fate during sexual development. 相似文献