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981.
cDNA display: a novel screening method for functional disulfide-rich peptides by solid-phase synthesis and stabilization of mRNA–protein fusions 下载免费PDF全文
982.
Shigeru Kitani Haruo Ikeda Takako Sakamoto Satoru Noguchi Takuya Nihira 《Applied microbiology and biotechnology》2009,82(6):1089-1096
Avermectin is an important macrocyclic polyketide produced by Streptomyces avermitilis and widely used as an anthelmintic agent in the medical, veterinary, and agricultural fields. The avermectin biosynthetic
gene cluster contains aveR, which belongs to the LAL-family of regulatory genes. In this study, aveR was inactivated by gene replacement in the chromosome of S. avermitilis, resulting in the complete loss of avermectin production. The aveR mutant was unable to convert an avermectin intermediate to any avermectin derivatives, and complementation by intact aveR and its proper upstream region restored avermectin production in the mutant, suggesting that AveR is a positive regulator
controlling the expression of both polyketide biosynthetic genes and postpolyketide modification genes in avermectin biosynthesis.
Despite the general concept that an increased amount of a positive pathway-specific regulator leads to higher production,
a higher amount of aveR resulted in complete loss of avermectin, indicating that there is a maximum threshold concentration of aveR for the production of avermectin. 相似文献
983.
Glycosylation defects activate filamentous growth Kss1 MAPK and inhibit osmoregulatory Hog1 MAPK 总被引:1,自引:0,他引:1 下载免费PDF全文
The yeast filamentous growth (FG) MAP kinase (MAPK) pathway is activated under poor nutritional conditions. We found that the FG‐specific Kss1 MAPK is activated by a combination of an O‐glycosylation defect caused by disruption of the gene encoding the protein O‐mannosyltransferase Pmt4, and an N‐glycosylation defect induced by tunicamycin. The O‐glycosylated membrane proteins Msb2 and Opy2 are both essential for activating the FG MAPK pathway, but only defective glycosylation of Msb2 activates the FG MAPK pathway. Although the osmoregulatory HOG (high osmolarity glycerol) MAPK pathway and the FG MAPK pathway share almost the entire upstream signalling machinery, osmostress activates only the HOG‐specific Hog1 MAPK. Conversely, we now show that glycosylation defects activate only Kss1, while activated Kss1 and the Ptp2 tyrosine phosphatase inhibit Hog1. In the absence of Kss1 or Ptp2, however, glycosylation defects activate Hog1. When Hog1 is activated by glycosylation defects in ptp2 mutant, Kss1 activation is suppressed by Hog1. Thus, the reciprocal inhibitory loop between Kss1 and Hog1 allows only one or the other of these MAPKs to be stably activated under various stress conditions. 相似文献
984.
Interaction of light and hormone signals in germinating seeds 总被引:1,自引:0,他引:1
Mitsunori Seo Eiji Nambara Giltsu Choi Shinjiro Yamaguchi 《Plant molecular biology》2009,69(4):463-472
Seed germination is regulated by several environmental factors, such as moisture, oxygen, temperature, light, and nutrients.
Light is a critical regulator of seed germination in small-seeded plants, including Arabidopsis and lettuce. Phytochromes,
a class of photoreceptors, play a major role in perceiving light to induce seed germination. Classical physiological studies
have long suggested the involvement of gibberellin (GA) and abscisic acid (ABA) in the phytochrome-mediated germination response.
Recent studies have demonstrated that phytochromes modulate endogenous levels of GA and ABA, as well as GA responsiveness.
Several key components that link the perception of light and the modulation of hormone levels and responsiveness have been
identified. Complex regulatory loops between light, GA and ABA signaling pathways have been uncovered. 相似文献
985.
Katsuyoshi Matsunami Hideaki Otsuka Kazunari Kondo Takakazu Shinzato Masatoshi Kawahata Kentaro Yamaguchi Yoshio Takeda 《Phytochemistry》2009,70(10):1277-1285
A lignan glucoside, (+)-pinoresinol 4-O-[6″-O-galloyl]-β-d-glucopyranoside (1), and two megastigmane glucosides, named macarangiosides E and F (2, 3), together with 15 known compounds (4–18) were isolated from leaves of Macaranga tanarius (L.) Müll.-Arg. (Euphorbiaceae). Their structures were elucidated by spectroscopic and chemical analyses. In addition, the absolute stereochemistry of macarangiosides B and C isolated previously from the same plant was also determined for the first time. Compounds 1 and 2 were galloylated on glucose and possessed potent DPPH radical-scavenging activity. 相似文献
986.
Isolation and Characterization of Hydroxyproline-Rich Glycopeptide Signals in Black Nightshade Leaves 下载免费PDF全文
Gregory Pearce Ramcharan Bhattacharya Yu-Chi Chen Guido Barona Yube Yamaguchi Clarence A. Ryan 《Plant physiology》2009,150(3):1422-1433
A gene encoding a preprohydroxyproline-rich systemin, SnpreproHypSys, was identified from the leaves of black nightshade (Solanum nigrum), which is a member of a small gene family of at least three genes that have orthologs in tobacco (Nicotiana tabacum; NtpreproHypSys), tomato (Solanum lycopersicum; SlpreproHypSys), petunia (Petunia hybrida; PhpreproHypSys), potato (Solanum tuberosum; PhpreproHypSys), and sweet potato (Ipomoea batatas; IbpreproHypSys). SnpreproHypSys was induced by wounding and by treatment with methyl jasmonate. The encoded precursor protein contained a signal sequence and was posttranslationally modified to produce three hydroxyproline-rich glycopeptide signals (HypSys peptides). The three HypSys peptides isolated from nightshade leaf extracts were called SnHypSys I (19 amino acids with six pentoses), SnHypSys II (20 amino acids with six pentoses), and SnHypSys III (20 amino acids with either six or nine pentoses) by their sequential appearance in SnpreproHypSys. The three SnHypSys peptides were synthesized and tested for their abilities to alkalinize suspension culture medium, with synthetic SnHypSys I demonstrating the highest activity. Synthetic SnHypSys I was capable of inducing alkalinization in other Solanaceae cell types (or species), indicating that structural conformations within the peptides are recognized by the different cells/species to initiate signal transduction pathways, apparently through recognition by homologous receptor(s). To further demonstrate the biological relevance of the SnHypSys peptides, the early defense gene lipoxygenase D was shown to be induced by all three synthetic peptides when supplied to excised nightshade plants. 相似文献
987.
Gen Kume Keisuke Furumitsu Shinya Tanaka Atsuko Yamaguchi 《Environmental Biology of Fishes》2009,85(4):289-298
Size at sexual maturity, reproductive cycle, and fecundity of the guitarfish, Rhinobatos hynnicephalus, were examined in Ariake Bay, Japan. Females reached sexual maturity at a larger size than males [total length (TL) at 50%
sexual maturity: males, 431 mm; females, 476 mm]. Monthly gonadosomatic indices of males decreased abruptly from July to August.
Histological examinations confirmed the presence of mature spermatozoa in the testes in July, with semen in seminal vesicles
in July and August. Preovulatory ova were observed in females with near-term embryos in August. Parturition occurred in August,
immediately followed by mating, ovulation, and fertilization. Gestation period is approximately 1 year. Fertilized uterine
eggs without embryonic development were present throughout the annual reproductive cycle. Embryonic development began in June
and ended in August, indicating that R. hynnicephalus undergoes embryonic diapause (9 months). Fecundity increased with TL and ranged from 1 to 9 (mean, 4.4) embryos per litter. 相似文献
988.
Kei Ishibashi Tadahiko Tokumoto Hiroki Shirakawa Koichi Hashimoto Nobuhiro Kushida Tomohiko Yanagida Keiichi Shishido Ken Aikawa Osamu Yamaguchi Hiroshi Toma Kazunari Tanabe Tatsuo Suzutani 《Microbiology and immunology》2009,53(7):412-416
The gH of CMV is a major target for strain-specific neutralizing antibodies. To verify whether there is a correlation between HLA-DR type and strain-specific antibodies, antibodies against CMV gH in potential donors and recipients for renal transplantation were investigated. Among 471 subjects, 404 (86%) showed reactivity to CMV gH, but no antibodies against gH were detected in 67 (14%) subjects. The positive rates were over 80% in most HLA subpopulations. Fewer subjects with HLA-DR10 and DR11 had antibodies to CMV gH than did those without HLA-DR10 and DR11. HLA-DR10 and DR11 may be associated with fewer/non-responders for strain-specific neutralizing antibodies. 相似文献
989.
Knockdown of tight junction protein claudin-2 prevents bile canalicular formation in WIF-B9 cells 总被引:1,自引:0,他引:1
Seiichi Son Takashi Kojima Catherine Decaens Hiroshi Yamaguchi Tatsuya Ito Masafumi Imamura Masaki Murata Satoshi Tanaka Hideki Chiba Koichi Hirata Norimasa Sawada 《Histochemistry and cell biology》2009,131(3):411-424
The polarization of hepatocytes involves formation of functionally distinct sinusoidal (basolateral) and bile canalicular
(apical) plasma membrane domains that are separated by tight junctions. Although various molecular mechanisms and signaling
cascades including polarity complex proteins may contribute to bile canalicular formation in hepatocytes, the role of tight
junction proteins in bile canalicular formation remains unclear. To investigate the role of the integral tight junction protein
claudin-2 in bile canalicular formation, we depleted claudin-2 expression by siRNA in the polarized hepatic cell line WIF-B9
after treatment with or without phenobarbital. When WIF-B9 cells were treated with phenobarbital, claudin-2 expression and
tight junction strands were markedly increased together with induction of canalicular formation with a biliary secretion function.
Knockdown of claudin-2 prevented bile canalicular formation after treatment with or without phenobarbital. Furthermore, knockdown
of claudin-2 caused a change from a hepatic polarized phenotype to a simple polarized phenotype, together with upregulation
of pLKB1, pMAPK, pAkt and pp38 MAPK, but not pMLC, PTEN or cdc42, and an increase of intracellular vacuoles, which were present
before bile canalicular formation. These results suggest that claudin-2 may affect not only the bile canalicular seal but
also bile canalicular formation. 相似文献
990.
Takeo Sato Shugo Maekawa Shigetaka Yasuda Yutaka Sonoda Etsuko Katoh Takanari Ichikawa Miki Nakazawa Motoaki Seki Kazuo Shinozaki Minami Matsui Derek B. Goto Akira Ikeda Junji Yamaguchi 《The Plant journal : for cell and molecular biology》2009,60(5):852-864
Plants are able to sense and respond to changes in the balance between carbon (C) and nitrogen (N) metabolite availability, known as the C/N response. During the transition to photoautotrophic growth following germination, growth of seedlings is arrested if a high external C/N ratio is detected. To clarify the mechanisms for C/N sensing and signaling during this transition period, we screened a large collection of FOX transgenic plants, overexpressing full‐length cDNAs, for individuals able to continue post‐germinative growth under severe C/N stress. One line, cni1‐D (carbon/nitrogen insensitive 1‐dominant), was shown to have a suppressed sensitivity to C/N conditions at both the physiological and molecular level. The CNI1 cDNA encoded a predicted RING‐type ubiquitin ligase previously annotated as ATL31. Overexpression of ATL31 was confirmed to be responsible for the cni1‐D phenotype, and a knock‐out of this gene resulted in hypersensitivity to C/N conditions during post‐germinative growth. The ATL31 protein was confirmed to contain ubiquitin ligase activity using an in vitro assay system. Moreover, removal of this ubiquitin ligase activity from the overexpressed protein resulted in the loss of the mutant phenotype. Taken together, these data demonstrated that CNI1/ATL31 activity is required for the plant C/N response during seedling growth transition. 相似文献