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1.
The molybdenum and tungsten dinitrogen-organonitrile complexes trans-[M(N2)(NCR)(dppe)2] (2, M=Mo; 4, M=W; R=Ph, C6H4Me-p, C6H4OMe-p, Me; dppe=Ph2PCH2CH2PPh2) underwent double protonation at the nitrile carbon atom with loss of N2 and a change in oxidation state to +4 on treatment with hydrochloric acid to afford the cationic imido complexes trans-[MCl(NCH2R)(dppe)2]+. The solid-state structure of trans-[WCl(NCH2CH3)(dppe)2][PF6]·CH2Cl2 was determined by single-crystal X-ray analysis. Protonation of complexes 2 by fluoroboric acid or hydrobromic acid also formed the similar imido complexes trans-[MoX(NCH2R)(dppe)2]+ (X=F, Br). In contrast, the dinitrogen complex trans-[Mo(N2)2(dppe)2] reacted with two equiv. of benzoylacetonitrile, a nitrile with acidic CH hydrogen atoms, to give the nitrido complex trans-[Mo(N)(NKCCHCOPh)(dppe)2] (12), which was accompanied by evolution of dinitrogen and the formation of 1-phenyl-2-propen-1-one in high yields. For complex 12, the zwitterionic structure, where the anionic enolate ligand PhC(O+)=CHCN coordinates to the cationic Mo(IV) center through its nitrogen atom, was confirmed by spectroscopic measurements and single-crystal X-ray analysis. A unique intermolecular aromatic C---HO hydrogen bonding was observed in that crystal structure. Complex 12 is considered to be formed via the cleavage of the CN triple bond of benzoylacetonitrile on the metal. A reaction mechanism is proposed, which includes the double protonation of the nitrile carbon atom of the ligating benzoylacetonitrile on a low-valent molybdenum center. 相似文献
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Novel mono-O-acetylated GM3s, one containing 9-O-acetylN-glycolyl neuraminic acid and another containing 6-O-acetyl galactose, were isolated as a mixture from equine erythrocytes, and the structures were characterized by one- and two-dimensional proton nuclear magnetic resonance (NMR) and fast atom bombardment-mass spectrometry (FAB-MS). The position of theO-acetyl residue was identified by the downfield shift of the methylene protons at C-9 ofN-glycolyl neuraminic acid (9-O-Ac GM3) and C-6 of galactose (6-O-Ac GM3) in the NMR spectrum, in comparison to the respective non-acetylated counterparts. To confirm the presence of 6-O-Ac GM3, theO-acetylated GM3 mixture was desialylated withArthrobacter neuraminidase, giving 6-O-acetyl galactosyl glucosylceramide, the structure of which was estimated by NMR and FAB-MS, together with non-acetylated lactosylceramide with a ratio of 1:1.
Abbreviations: Ac, acetyl; Gc, glycolyl; NeuGc,N-Gc neuraminic acid; GM3 (Gc), GM3 containing NeuGc (II3NeuGc-LacCer); 4-O-Ac GM3 (Gc), GM3 containing 4-O-Ac NeuGc; 9-O-Ac GM3 (Gc), GM3 containing 9-O-Ac NeuGc; 6-O-Ac GM3 (Gc), GM3 containing 6-O-Ac Gal; 1D-NMR, one-dimensional nuclear magnetic resonance spectrometry; 2D-COSY, two-dimensional chemical shift-correlated spectrometry; FAB-MS, fast atom bombardment-mass spectrometry; GLC, gas-layer chromatography; GC-MS, gas chromatography-mass spectrometry; TLC, thin-layer chromatography; Ggl, ganglioside; Cer, ceramide; CMH, monohexosylceramide; LacCer, lactosylceramide; 6-O-Ac LacCer, LacCer containing 6-O-Ac Gal; Me2SO-d6,2H6-dimethylsufloxide; CMW, chloroform-methanol-water; Nomenclature and abbreviations of glycosphingolipids follow the system of Svennerholm (J Neurochem [1963]10: 613–23) and those recommended by the IUPAC-IUB Nomenclature Commission (Lipids [1977]12: 455–68). 相似文献
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Takeshi Nishimura Setsuko Yamamoto Takaaki Yamamoto Munekiyo Kaneko Youichi Hara 《Prostaglandins & other lipid mediators》1996,51(2):149-159
The antithrombotic effect of topical application of the 3-oxamethano-prostaglandin (PG) I1 analog, SM-10902 in the microcirculation and in vitro antiplatelet functions of its active form SM-10906 were estimated in comparison with PGI2 and PGE1. In rat platelets, SM-10906 evoked accumulation of intracellular cyclic adenosine 3′,5′-monophosphate, and exhibited antiaggregatory and disaggregatory activities, which were all enhanced by the phosphodiesterase inhibitor theophylline. Additionally, SM-10906 was shown to inhibit platelet adhesion to collagen in human platelet-rich plasma. PGI2 and PGE1 also showed in vitro antiplatelet effects in the order of PGI2 > SM-10906 ≥ PGE1. SM-10902 exhibited a dose-dependent antithrombotic effect in the guinea pig mesenteric arteriole by a topical application, and this activity might be exerted by the antiplatelet functions of SM-10906. Although SM-10906, PGI2 and PGE1 also showed the antithrombotic effects, SM-10902 was the most potent. In conclusion, the present studies indicate that an external topical preparation of SM-10902 may be useful for the therapy of peripheral circulatory insufficiency. 相似文献
6.
Naoki Yokotani Takanari Ichikawa Youichi Kondou Satoru Maeda Masaki Iwabuchi Masaki Mori Hirohiko Hirochika Minami Matsui Kenji Oda 《Plant molecular biology》2009,71(4-5):391-402
Plant growth and crop production are limited by environmental stress. We used a large population of transgenic Arabidopsis expressing rice full-length cDNAs to isolate the rice genes that improve the tolerance of plants to environmental stress. By sowing T2 seeds of the transgenic lines under conditions of salinity stress, the salt-tolerant line R07047 was isolated. It expressed a rice gene, OsSMCP1, which encodes a small protein with a single C2 domain, a Ca2+-dependent membrane-targeting domain. Retransformation of wild-type Arabidopsis revealed that OsSMCP1 is responsible for conferring the salt tolerance. It is particularly interesting that R07047 and newly constructed OsSMCP1-overexpressing Arabidopsis showed enhanced tolerance not only to high salinity but also to osmotic, dehydrative, and oxidative stresses. Furthermore, R07047 showed improved resistance to Pseudomonas syringae. The OsSMCP1 expression in rice is constitutive. Particle-bombardment-mediated transient expression analysis revealed that OsSMCP1 is targeted to plastids in rice epidermal cells. It induced overexpression of several nuclear encoded genes, including the stress-associated genes, in transgenic Arabidopsis. No marked morphological change or growth retardation was observed in R07047 or retransformants. For molecular breeding to improve the tolerance of crops against environmental stress, OsSMCP1 is a promising candidate. 相似文献
7.
Youichi Tamai Hiroshi Shinmoto Masayoshi Takakuwa 《Bioscience, biotechnology, and biochemistry》2013,77(12):2713-2721
A thermo-labile antigen (TLA) on the yeast cell surface was isolated from a yeast cell autolyzate and purified to a homogeneous state by chromatography on an immunoadsorbent affinity column. The molecular weight of TLA was about 1.45 x 105 on SDS-polyacrylamide gel electrophoresis and about 1.5 x l05 on gel chromatography on Sephadex G-200. The TLA contained 74.5% protein and 25.5% sugar. It was characterized by high contents of glycine, glutamic acid, serine and aspartic acid. Half-cystine, methionine, histidine and arginine were not found. The sugar moiety was composed of galactose, mannose, N-acetylglucosamine and fucose. The antigenic determinant of TLA was distinct from that of cell wall mannan in the Ouchterlony immunodiffusion test. No precipitin line against anti-TLA serum was observed, when TLA was heated at 90°C for 10 min. Oxidation with periodate had little effect on antigenicity, but digestion with Pronase or treatment with protein denaturants resulted in loss of the antigenicity. These results suggest that the protein moiety plays an important role as the antigenic determinant of TLA. Moreover, the antiserum specific to TLA agglutinated fresh yeast cells, and the distribution of TLA was apparent on the yeast cell surface by immunofluorescence staining. These findings suggest that TLA molecules were exposed on the outer surface of the yeast cell wall. 相似文献
8.
Youichi Suzuki Wei-Xin Chin Qi'En Han Koji Ichiyama Ching Hua Lee Zhi Wen Eyo Hirotaka Ebina Hirotaka Takahashi Chikako Takahashi Beng Hui Tan Takayuki Hishiki Kenji Ohba Toshifumi Matsuyama Yoshio Koyanagi Yee-Joo Tan Tatsuya Sawasaki Justin Jang Hann Chu Subhash G. Vasudevan Kouichi Sano Naoki Yamamoto 《PLoS pathogens》2016,12(1)
Dengue virus (DENV) is one of the most important arthropod-borne pathogens that cause life-threatening diseases in humans. However, no vaccine or specific antiviral is available for dengue. As seen in other RNA viruses, the innate immune system plays a key role in controlling DENV infection and disease outcome. Although the interferon (IFN) response, which is central to host protective immunity, has been reported to limit DENV replication, the molecular details of how DENV infection is modulated by IFN treatment are elusive. In this study, by employing a gain-of-function screen using a type I IFN-treated cell-derived cDNA library, we identified a previously uncharacterized gene, C19orf66, as an IFN-stimulated gene (ISG) that inhibits DENV replication, which we named Repressor of yield of DENV (RyDEN). Overexpression and gene knockdown experiments revealed that expression of RyDEN confers resistance to all serotypes of DENV in human cells. RyDEN expression also limited the replication of hepatitis C virus, Kunjin virus, Chikungunya virus, herpes simplex virus type 1, and human adenovirus. Importantly, RyDEN was considered to be a crucial effector molecule in the IFN-mediated anti-DENV response. When affinity purification-mass spectrometry analysis was performed, RyDEN was revealed to form a complex with cellular mRNA-binding proteins, poly(A)-binding protein cytoplasmic 1 (PABPC1), and La motif-related protein 1 (LARP1). Interestingly, PABPC1 and LARP1 were found to be positive modulators of DENV replication. Since RyDEN influenced intracellular events on DENV replication and, suppression of protein synthesis from DENV-based reporter construct RNA was also observed in RyDEN-expressing cells, our data suggest that RyDEN is likely to interfere with the translation of DENV via interaction with viral RNA and cellular mRNA-binding proteins, resulting in the inhibition of virus replication in infected cells. 相似文献
9.
Jariya Roddee Youichi Kobori Yupa Hanboonsong 《Entomologia Experimentalis et Applicata》2019,167(2):108-117
The leafhopper Matsumuratettix hiroglyphicus (Matsumura) (Hemiptera: Cicadellidae) is the most important vector of sugarcane white leaf (SCWL) phytoplasma that significantly affects the sugarcane crop in Asia. Here, we aimed to study the characteristics of SCWL phytoplasma transmission by M. hiroglyphicus. To this end, the stylet penetration activities performed during the acquisition access period (AAP) and inoculation access period (IAP) were investigated by the direct current electrical penetration graph technique and confirmed by quantitative polymerase chain reaction (qPCR). Additionally, the latent period (LP) of SCWL phytoplasma in the vector was determined by qPCR and localised by fluorescent in situ hybridisation. The results indicated that the acquisition of SCWL phytoplasma occurred during phloem ingestion (waveform D), whereas its inoculation was associated with salivation into the phloem sieve element (waveform C). The minimum AAP was 15 min and the minimum duration of phloem ingestion was 2.35 min. The minimum LP of SCWL phytoplasma in the vector was at least 14 days; then, SCWL phytoplasma moved to the salivary glands of the insect, enabling the transmission of the pathogen to the host plants. The minimum IAP for a successful transmission of SCWL phytoplasma to the host plants was 11–12 min, with a minimum duration of salivation into phloem of 1.35 min. The female vectors had higher SCWL phytoplasma copy numbers than the male vectors, and displayed faster AAP, IAP, and LP. Overall, our findings provide important information related to the feeding behaviour of M. hiroglyphicus and its effect on the transmission of SCWL phytoplasma. 相似文献
10.
Disruption of phospholipase B gene, PLB1, increases the survival of baker's yeast Torulaspora delbrueckii 总被引:2,自引:0,他引:2
Abstract An uracil auxotrophic mutant of baker's yeast Torulaspora delbrueckii , which is resitant to 5-fluoro-orotic acid, was complemented by transformation with YEp24 which harbors 2 μm origin and URA3 derived from Saccharomyces cerevisiae . The phospholipase B in T. delbrueckii cells is active in both acidic and alkaline conditions. However, activity of phospholipase B gene ( PLB1 ) in cells of disruption mutant ( plbI : : URA3 ) was lost in both conditions, which indicates that all phospholipase B activity is encoded by a single gene (or a single polypeptide) in these yeast cells. Over-expression of PLB1 with YEp plasmid vector in T. delbrueckii cells showed ∼ 2.5-fold increase in phospholipase B activity, comparing with that in wild-type cells. Cells of plb1 Δ mutant showed increased survival when cells of plb1 Δ mutant and wild-type strain were incubated in water at 30 °C. Cells of PLB1 -over-expressed strain died rapidly even during the cultivation period, indicating that phospholipase B activity may be a determinant for the survival of this yeast. 相似文献