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991.
Two forms of the restriction enzyme HindIII were alternated with each other under some physiological or biochemical conditions. Addition of a low amount of phase T7 to the culture of HindIII-producing Haemophilus influenzae Rd, resulted in appearance of some amounts of the P2 fraction of HindIII, which was eluted with a high concentration of KCI from a phosphocellulose column. Higher amounts of T7 caused a decrease of the P2 fraction; finally the alternative PI fraction of HindIII, which was eluted with a lower concentration of KCI, remained exclusively.Addition of disaccharides such as maltose and trehalose to the bacterial extract, yielded more P2, although the disaccharides inhibited to this enzyme. Urea showed an interesting distribution of these two forms of HindIII. Phosphocellulose chromatography in the presence of 2 m urea generated a broad peak of HindIII Activity. Addition of 4 m urea, on the contrary, showed only one active peak of this enzyme. The HindIII could be purified by the following DEAE-cellulose chromatography.These results indicate the presence of only one kind of HindIII molecule, which was alternated between free and bound forms, and a certain kind of factor that would equilibrate these two forms. 相似文献
992.
Susumu Ikegami Yuji Kamiya Saburo Tamura 《Bioscience, biotechnology, and biochemistry》2013,77(6):1087-1089
An extracellular alkaline proteinase produced by Candida lipolytica was purified through iso-propanol and ammonium sulfate precipitation, decolorization with DEAE-cellulose, gel filtration with Sephadex G–100 and ion-exchange chromatography on DEAE-Sephadex A–50. The optimum pH of its caseinolytic activity was 9.0, and this activity was completely inactivated with DFP but not with chelating reagents, PCMB, STI, TLCK, TPCK, or SSI. This enzyme also hydrolyzed salmin and synthetic esters, such as Bz. Arg. OEt, Bz. His. OMe, Tos. Lys. OMe or Ac. Tyr. OEt, and the optimum pH of its esterase activity was 8.0. The molecular weight of the enzyme was estimated to be about 30,000 by the gel filtration method. These facts indicated that this enzyme was distinguishable from other microbial alkaline proteinases so far studied. 相似文献
993.
Evaluation of Tomato Hybrids Carrying Ty‐1 and Ty‐2 Loci to Japanese Monopartite Begomovirus Species
Muhammad Shafiq Shahid Takuya Ito Junji Kimbara Ayumu Onozato Keiko T. Natsuaki Masato Ikegami 《Journal of Phytopathology》2013,161(3):205-209
Tobacco leaf curl Japan virus, Honeysuckle yellow vein mosaic virus and Tomato yellow leaf curl virus are three begomoviruses that infect tomato crops in Japan. Tomato infection by begomoviruses has increased in Japan after the development of a high level of resistance to certain insecticides in some populations of the vector B. tabaci biotypes ‘B and Q’. Ty‐1 and Ty‐2 homozygous tomato hybrids were evaluated for reaction to monopartite begomovirus species in Japan by Agrobacterium‐mediated inoculation. Test plants were evaluated by a disease assessment scale (DAS), varying from 1 = no symptoms to 4 = severe symptoms, and systemic infection was evaluated by polymerase chain reaction (PCR), using specific begomovirus primers for each virus. Ty‐1 hybrids showed tolerance to HYVMV and with a large number of plants being neither virus‐free nor symptom‐free. The response of Ty‐1 hybrids was also resistant to moderately resistant against TbLCJV. The response of Ty‐2 hybrids was resistant to highly resistant against the three monopartite begomoviruses, when compared with susceptible plants. 相似文献
994.
Tomoya Shiro Keisuke Kakiguchi Hirotada Takahashi Hidetaka Nagata Masanori Tobe 《Bioorganic & medicinal chemistry》2013,21(11):2868-2878
To identify compounds with strong mPGES-1 inhibitory activity and clear in vitro ADME profile, we optimized the lead compound 1 by carrying our substitutions at the C(7)- and C(8)-positions. Replacement of the bromine atom of 1 with various substituents led to identification of the phenyl group as the best C(7)-substituent giving strong inhibitory activity with good in vitro ADME profile. Further SAR examination on both the C(2)- and the C(7)-phenyl groups provided compound 39 as the best candidate for further development. Compound 39 exhibited strong mPGES-1 inhibitory activity (IC50 = 4.1 nM), potent cell-based functional activity (IC50 = 33 nM) with good mPGES-1 selectivity (over 700-fold), excellent in vitro ADME profile, and good oral absorption in rat PK study. 相似文献
995.
Janet Franklin Frank W. Davis Makihiko Ikegami Alexandra D. Syphard Lorraine E. Flint Alan L. Flint Lee Hannah 《Global Change Biology》2013,19(2):473-483
Recent studies suggest that species distribution models (SDMs) based on fine‐scale climate data may provide markedly different estimates of climate‐change impacts than coarse‐scale models. However, these studies disagree in their conclusions of how scale influences projected species distributions. In rugged terrain, coarse‐scale climate grids may not capture topographically controlled climate variation at the scale that constitutes microhabitat or refugia for some species. Although finer scale data are therefore considered to better reflect climatic conditions experienced by species, there have been few formal analyses of how modeled distributions differ with scale. We modeled distributions for 52 plant species endemic to the California Floristic Province of different life forms and range sizes under recent and future climate across a 2000‐fold range of spatial scales (0.008–16 km2). We produced unique current and future climate datasets by separately downscaling 4 km climate models to three finer resolutions based on 800, 270, and 90 m digital elevation models and deriving bioclimatic predictors from them. As climate‐data resolution became coarser, SDMs predicted larger habitat area with diminishing spatial congruence between fine‐ and coarse‐scale predictions. These trends were most pronounced at the coarsest resolutions and depended on climate scenario and species' range size. On average, SDMs projected onto 4 km climate data predicted 42% more stable habitat (the amount of spatial overlap between predicted current and future climatically suitable habitat) compared with 800 m data. We found only modest agreement between areas predicted to be stable by 90 m models generalized to 4 km grids compared with areas classified as stable based on 4 km models, suggesting that some climate refugia captured at finer scales may be missed using coarser scale data. These differences in projected locations of habitat change may have more serious implications than net habitat area when predictive maps form the basis of conservation decision making. 相似文献
996.
Shiro Kitano Mashimo Nakayama Akio Yamane Yusuke Tsukahara Masahiko Amano 《Analytical biochemistry》2011,408(2):197
Molecularly targeted agents for cancer therapy are recognized as being effective and are gaining in popularity. However, the efficacy of the agents depends on the status of the targeted molecule such as the number of molecules expressed, activity, and mutation. Therefore, the use of companion diagnostics for investigating the status of the targeted molecule prior to therapy is highly important. We developed a simple and cost-effective somatic mutation detection method called the fluorescence resonance energy transfer-based preferential homoduplex formation assay (FRET–PHFA). By using double-stranded labeled DNA and fluorescence measurement with thermal control, this method provides higher reproducibility, easier handling, less risk for contamination, shorter assay time (only ∼15 min), and less cost compared with conventional PHFA. Here we report the evaluation of FRET–PHFA on the detection of multiallelic KRAS mutations in codons 12 and 13 compared with the TheraScreen clinical diagnostics kit. We found that FRET–PHFA detected KRAS mutations (1.25–50%) from all cell line DNA titration samples. 相似文献
997.
Inhibition of preovulatory synthesis and action of progesterone impairs ovulation in rodents. We evaluated effects of supplementation of exogenous progesterone on human chorionic gonadotropin (hCG)-induced ovulatory response in immature rats. Equine CG-primed mature follicles responded to hCG with induction of immunoreactive steroidogenic acute regulatory protein (StAR) mainly in thecal layers and a transient enhancement in progesterone synthesis peaking at 6h after hCG (hCG6h). A single dose of natural progesterone or a synthetic agonist (MP) at hCG0h both decreased ovulation rates in dose-dependent manners. MP was still effective when treated at hCG4h. Treatment with these agents at hCG0h reduced circulating progesterone and thecal expression of StAR at hCG6h. The treatments further attenuated induction of cyclooxygenase (COX)-2 in mural granulosa cells and ovarian prostaglandin (PG) E(2) level at hCG8h. We also found a significant reduction in bromo-deoxyuridine incorporation by mural granulosa cells. Obtained results show that the early treatment with exogenous progesterone agonist caused attenuated amplitude of endogenous progesterone surge, reduced COX-2/PGE(2) system, dysregulated mitosis of granulosa cells, and decreased oocytes release. We suggest that optimal progesterone synthesis and action are an early critical component of hCG-initiated ovulatory cascade that regulates biochemical function of granulosa cells. 相似文献
998.
999.
Konuma T Chatani E Yagi M Sakurai K Ikegami T Naiki H Goto Y 《Journal of molecular biology》2011,405(3):851-34253
Amyloid fibril elongation in denatured proteins involves cycles of coupled binding and misfolding. To gain insights into possible kinetic intermediates, we performed hydrogen/deuterium exchange of amide protons during fibril elongation with β2-microglobulin (β2-m) at pD = 2.5, under which conditions β2-m is acid denatured. To study the conformational change in monomeric β2-m monitored by NMR spectroscopy, we used 15N-labeled monomers and nonlabeled seeds. Pulse-labeling hydrogen/deuterium exchange with a quenched-flow apparatus indicated that the rate-limiting intermediate at pD = 2.5 is not protected from the exchange, even disrupting a hydrophobic cluster present in the acid-denatured β2-m. Significant protection was acquired upon transition to the fibrils. In view of the suggestion that the rate-limiting intermediates are bound to the lateral surface of seed fibrils, weak interactions with a largely unfolded conformation might be useful for their dynamic sliding to the growing ends. The results support a new model of fibril elongation with intermediates bound to the lateral surface of seeds. 相似文献
1000.
Fujishiro T Shoji O Nagano S Sugimoto H Shiro Y Watanabe Y 《The Journal of biological chemistry》2011,286(34):29941-29950
Cytochrome P450SPα (CYP152B1) isolated from Sphingomonas paucimobilis is the first P450 to be classified as a H2O2-dependent P450. P450SPα hydroxylates fatty acids with high α-regioselectivity. Herein we report the crystal structure of P450SPα with palmitic acid as a substrate at a resolution of 1.65 Å. The structure revealed that the Cα of the bound palmitic acid in one of the alternative conformations is 4.5 Å from the heme iron. This conformation explains the highly selective α-hydroxylation of fatty acid observed in P450SPα. Mutations at the active site and the F–G loop of P450SPα did not impair its regioselectivity. The crystal structures of mutants (L78F and F288G) revealed that the location of the bound palmitic acid was essentially the same as that in the WT, although amino acids at the active site were replaced with the corresponding amino acids of cytochrome P450BSβ (CYP152A1), which shows β-regioselectivity. This implies that the high regioselectivity of P450SPα is caused by the orientation of the hydrophobic channel, which is more perpendicular to the heme plane than that of P450BSβ. 相似文献