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排序方式: 共有802条查询结果,搜索用时 31 毫秒
51.
Kazutoshi Nishijima Mai Tanaka Yusuke Sakai Chihiro Koshimoto Masatoshi Morimoto Teruo Watanabe Jianglin Fan Shuji Kitajima 《Cryobiology》2014
We investigated the effects of antifreeze protein (AFP) III supplementation on the cryopreservation of rabbit sperm cells and embryos. Ejaculated semen was collected from male Japanese white (JW) rabbits and divided into four AFP-supplemented groups (0.1 μg/ml, 1 μg/ml, 10 μg/ml, 100 μg/ml) and one control group with no AFP-supplementation. The semen samples were treated with egg-yolk HEPES extender containing 6% acetamide before the sperm was cooled from room temperature to 5 °C, then packed into sperm straws. The straws were frozen in steam of liquid nitrogen (LN2) and then preserved in the LN2. The motility of the sperm after thawing in 37 °C water was analyzed. The percentage of rapidly motile sperm in the 1 μg/ml AFP group was significantly higher than in the control group. Morulae were collected from female JW rabbits and divided into three AFP-supplemented groups (100 ng/ml, 500 ng/ml, 1000 ng/ml) and one control group. The morulae, immersed in an embryo-freezing solution (M199-HEPES containing 20% ethylene glycol, 20% dimethylsulfoxide, 10% fetal bovine serum and 0.25 M sucrose), were packed into open pulled embryo straws and vitrified in LN2. The frozen embryos were thawed in the embryo-freezing solution, and the rates of embryo survival and development to blastocyte stage were analyzed after incubation for 72 h. The development rate of the embryos in the 500 ng/ml AFP group was significantly higher than in the control group, but that in the 1000 ng/ml AFP group was significantly lower. In conclusion, the appropriate dose of AFP III increased the number of rapidly motile sperm and embryo survival following freezing and thawing. The results suggest that supplementation with AFP III can increase the efficiency of cryopreservation of rabbit sperm cells and embryos. 相似文献
52.
Gao J Luo J Li Y Fan R Zhao H Guan G Liu J Wiske B Sugimoto C Yin H 《Experimental & applied acarology》2007,41(4):289-303
A primary cDNA library with a size of 1.34 × 106 PFU was constructed from Haemaphysalis qinghaiensis eggs and was immunoscreened with rabbit anti-H. qinghaiensis serum. One clone (Hq22, named following those clones obtained from adult Haemaphysalis qinghaiensis cDNA library which we constructed before) screened from the cDNA library was selected randomly for sequencing. The entire
sequence of the clone was subsequently obtained using rapid amplification of the cDNA ends (RACE). A search of the cloned
sequence against GenBank revealed that it related to ribosomal protein L23a (Rpl23a) and had a high percentage similarity
to this protein from different species. Conserved domains for Rpl23a were also identified in the cloned sequence. Expression
analysis by RT-PCR showed that this gene is expressed in salivary glands, midguts, other tissues and different developmental
stages of H. qinghaiensis. Based on the H. qinghaiensis Rpl23a sequence, open reading frames (ORF) of Rpl23a of Heamaphysalis longicornis and Boophilus microplus were also cloned and were performed for comparison with Rpl23a of H. qinghaiensis and other organisms as well. Vaccine based on Rpl23a recombinant protein cannot protect sheep against H. qinghaiensis. 相似文献
53.
Wheat SOC1 functions independently of WAP1/VRN1, an integrator of vernalization and photoperiod flowering promotion pathways 总被引:1,自引:0,他引:1
Naoki Shitsukawa Chihiro Ikari Tadayuki Mitsuya Takeshi Sakiyama Atsushi Ishikawa Shigeo Takumi Koji Murai 《Physiologia plantarum》2007,130(4):627-636
Heading time in bread wheat ( Triticum aestivum L.) is determined by three characters – vernalization requirement, photoperiodic sensitivity and narrow-sense earliness (earliness per se) – which are involved in the phase transition from vegetative to reproductive growth. The wheat APETALA1 ( AP1 )-like MADS-box gene, wheat AP1 ( WAP1 , identical with VRN1 ), has been identified as an integrator of vernalization and photoperiod flowering promotion pathways. A MADS-box gene, SUPPRESSOR OF OVEREXPRESSION OF CO 1 ( SOC1 ) is an integrator of flowering pathways in Arabidopsis . In this study, we isolated a wheat ortholog of SOC1 , wheat SOC1 ( WSOC1 ), and investigated its relationship to WAP1 in the flowering pathway. WSOC1 is expressed in young spikes but preferentially expressed in leaves. Expression starts before the phase transition and is maintained during the reproductive growth phase. Overexpression of WSOC1 in transgenic Arabidopsis plants caused early flowering under short-day conditions, suggesting that WSOC1 functions as a flowering activator in Arabidopsis . WSOC1 expression is affected neither by vernalization nor photoperiod, whereas it is induced by gibberellin at the seedling stage. Furthermore, WSOC1 is expressed in transgenic wheat plants in which WAP1 expression is cosuppressed. These findings indicate that WSOC1 acts in a pathway different from the WAP1 -related vernalization and photoperiod pathways. 相似文献
54.
55.
Molecular basis of guanine nucleotide dissociation inhibitor activity of human neuroglobin by chemical cross-linking and mass spectrometry 总被引:1,自引:0,他引:1
Kitatsuji C Kurogochi M Nishimura S Ishimori K Wakasugi K 《Journal of molecular biology》2007,368(1):150-160
Oxidized human neuroglobin (Ngb), a heme protein expressed in the brain, has been proposed to act as a guanine nucleotide dissociation inhibitor (GDI) for the GDP-bound form of the heterotrimeric G protein alpha-subunit (Galpha(i)). Here, to elucidate the molecular mechanism underlying the GDI activity of Ngb, we used an glutathione-S-transferase pull-down assay to confirm that Ngb competes with G-protein betagamma-subunits (Gbetagamma) for binding to Galpha(i), and identified the Galpha(i)-binding site in Ngb by chemical cross-linking with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and sulfo-N-hydroxysuccinimide, coupled with mass spectrometry (MS). Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS analysis for tryptic peptides derived from the cross-linked Ngb-Galpha(i) complex revealed several binding regions in Ngb. Furthermore, MALDI-TOF/TOF MS analysis of the cross-linked Ngb and Galpha(i) peptides, together with the MS/MS scoring method, predicted cross-linking between Glu60 (Ngb) and Ser206 (Galpha(i)), and between Glu53 (Ngb) and Ser44 (Galpha(i)). Because Ser206 of Galpha(i) is located in the region that contacts Gbetagamma, binding of Ngb could facilitate the release of Gbetagamma from Galpha(i). Binding of Ngb to Galpha(i) would also inhibit the exchange of GDP for GTP, because Ser44 (Galpha(i)) is adjacent to the GDP-binding site and Glu53 (Ngb), which is cross-linked to Ser44 (Galpha(i)), could be located close to GDP. Thus, we have identified, for the first time, the sites of interaction between Ngb and Galpha(i), enabling us to discuss the functional significance of this binding on the GDI activity of Ngb. 相似文献
56.
Lee S Shinji C Ogura K Shimizu M Maeda S Sato M Yoshida M Hashimoto Y Miyachi H 《Bioorganic & medicinal chemistry letters》2007,17(17):4895-4900
We designed and synthesized hydroxamic acid derivatives bearing a 4-(3-pyridyl)phenyl group as a cap structure, and found that they exhibit potent histone deacetylase (HDAC) inhibitory activity. A representative compound, 17a, showed more potent growth-inhibitory activity against pancreatic cancer cells and greater upregulation of p21(WAF1/CIP1) expression than the clinically used HDAC inhibitor suberoylanilide hydroxamic acid (Zolinza). 相似文献
57.
The methanol extract of Sophora flavescens, which is used in traditional Chinese medicine (sophorae radix), showed potent Na(+)-glucose cotransporter (SGLT) inhibitory activity. Our search for active components identified many well-known flavonoid antioxidants: kurarinone, sophoraflavanone G, kushenol K, and kushenol N. 相似文献
58.
Morimura K Yamazaki C Hattori Y Makabe H Kamo T Hirota M 《Bioscience, biotechnology, and biochemistry》2007,71(11):2837-2840
A chromene-type compound, daedalin A (1), was isolated from mycelial culture broth of Daedalea dickinsii. Based on spectroscopic data, the structure of 1 was found to be (2R)-6-hydroxy-2-hydroxymethyl-2-methyl-2H-chromene. Daedalin A (1) strongly inhibited the activity of tyrosinase (IC(50): 194 muM). In addition, 1 also showed 1,1-diphenyl-2-picrylhydrazyl scavenging activity (IC(50): 16.9 microM) and superoxide anion scavenging activity (IC(50): 28.5 microM). 相似文献
59.
Junichi Nemoto Chihiro Harada Yoshihito Takei Naoto Katakura Masao Kaneko 《Photochemical & photobiological sciences》2007,6(1):77-82
Visible light decomposition of aqueous NH3 to N2 was investigated using a photocatalyst aqueous solution based on molecular photoelectron relay systems of either sensitizer (tris(2,2'-bipyridine)ruthenium(II), (Ru(bpy)3(2+))/potassium peroxodisulfate(K(2)S(2)O(8)) or Ru(bpy)3(2+)/methylviologen dichloride(MV2+)/O2, capable of using visible light instead of UV-driven semiconductors such as TiO2. It was confirmed by using an in situ visible absorption spectral change under irradiation that the Ru(II) complex is oxidized to the Ru(III) complex by K(2)S(2)O(8), and that the Ru(III) complex formed is stable without NH3, while the added NH3 was oxidized by the Ru(III) complex to produce the Ru(II) complex. In the presence of 1 mM NH3 aqueous solution, the Ru(III) complex was the predominant species under the photostationary state, but in the presence of 100 mM NH3, Ru(II) predominated. Gas-chromatographic analysis of the gaseous phase in the presence of 8.1 M NH3 showed that the photochemical oxidation of ammonia yielded N2. It was also demonstrated by using the in situ visible absorption spectrum under irradiation of the NH3 (1 M)/Ru(bpy)3(2+) (0.1 mM)/MV2+ (10 mM) system under Ar that MV+* is accumulated, showing that NH3 works as an electron donor for MV+* accumulation with simultaneous formation of the oxidized product of ammonia ((NH3)ox) without producing N2. It was suggested that the reduced product (MV+*) and the oxidized product ((NH3)ox) are in a kind of dynamic equilibrium prohibiting further oxidation of (NH3)ox by Ru(bpy)3(3+) to N2. In the O2 atmosphere, the oxidation of MV+* to MV2+ takes place to accumulate Ru(III) complex, so that (NH3)ox was further oxidized to N2. The high activity of IrO2 as a cocatalyst in this system was demonstrated. 相似文献