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991.
Received 23 March 1999/ Accepted in revised form 9 April 1999 相似文献
992.
Yuzy Matsuo Kouhei Nishino Kouhei Mizuno Takashi Akihiro Takashi Toda Yasuhiro Matsuo Tomohiro Kaino Makoto Kawamukai 《PloS one》2013,8(3)
Polypeptone is widely excluded from Schizosaccharomyces pombe growth medium. However, the reasons why polypeptone should be avoided have not been documented. Polypeptone dramatically induced cell lysis in the ura4 deletion mutant when cells approached the stationary growth phase, and this phenotype was suppressed by supplementation of uracil. To determine the specificity of this cell lysis phenotype, we created deletion mutants of other genes involved in de novo biosynthesis of uridine monophosphate (ura1, ura2, ura3, and ura5). Cell lysis was not observed in these gene deletion mutants. In addition, concomitant disruption of ura1, ura2, ura3, or ura5 in the ura4 deletion mutant suppressed cell lysis, indicating that cell lysis induced by polypeptone is specific to the ura4 deletion mutant. Furthermore, cell lysis was also suppressed when the gene involved in coenzyme Q biosynthesis was deleted. This is likely because Ura3 requires coenzyme Q for its activity. The ura4 deletion mutant was sensitive to zymolyase, which mainly degrades (1,3)-beta-D glucan, when grown in the presence of polypeptone, and cell lysis was suppressed by the osmotic stabiliser, sorbitol. Finally, the induction of cell lysis in the ura4 deletion mutant was due to the accumulation of orotidine-5-monophosphate. Cell wall integrity was dramatically impaired in the ura4 deletion mutant when grown in the presence of polypeptone. Because ura4 is widely used as a selection marker in S. pombe, caution needs to be taken when evaluating phenotypes of ura4 mutants. 相似文献
993.
Ahmed Bettaieb Jesse Bakke Naoto Nagata Kosuke Matsuo Yannan Xi Siming Liu Daniel AbouBechara Ramzi Melhem Kimber Stanhope Bethany Cummings James Graham Andrew Bremer Sheng Zhang Costas A. Lyssiotis Zhong-Yin Zhang Lewis C. Cantley Peter J. Havel Fawaz G. Haj 《The Journal of biological chemistry》2013,288(24):17360-17371
Protein-tyrosine phosphatase 1B (PTP1B) is a physiological regulator of glucose homeostasis and adiposity and is a drug target for the treatment of obesity and diabetes. Here we identify pyruvate kinase M2 (PKM2) as a novel PTP1B substrate in adipocytes. PTP1B deficiency leads to increased PKM2 total tyrosine and Tyr105 phosphorylation in cultured adipocytes and in vivo. Substrate trapping and mutagenesis studies identify PKM2 Tyr-105 and Tyr-148 as key sites that mediate PTP1B-PKM2 interaction. In addition, in vitro analyses illustrate a direct effect of Tyr-105 phosphorylation on PKM2 activity in adipocytes. Importantly, PTP1B pharmacological inhibition increased PKM2 Tyr-105 phosphorylation and decreased PKM2 activity. Moreover, PKM2 Tyr-105 phosphorylation is regulated nutritionally, decreasing in adipose tissue depots after high-fat feeding. Further, decreased PKM2 Tyr-105 phosphorylation correlates with the development of glucose intolerance and insulin resistance in rodents, non-human primates, and humans. Together, these findings identify PKM2 as a novel substrate of PTP1B and provide new insights into the regulation of adipose PKM2 activity. 相似文献
994.
Akihiko Matsuo Kazunori Atsumi Kazumi Nadaya Mitsuru Nakayama Shûichi Hayashi 《Phytochemistry》1981,20(5):1065-1068
13C NMR spectra of several 2,3-seco-alloaromadendrane-type acetyl hemiacetals were analysed and the structure of an additional plant growth-inhibitor was determined to be (+)-9α-acetoxyovalifoliene. The biological activity of the new compound is also described. 相似文献
995.
The Grueneberg ganglion is a specialized olfactory sensor. In mice, its activation induces freezing behavior. The topographical map corresponding to the central projections of its sensory axons is poorly defined, as well as the guidance molecules involved in its establishment. We took a transgenic approach to label exclusively Grueneberg sensory neurons and their axonal projections. We observed that a stereotyped convergence map in a series of coalescent neuropil-rich structures is already present at birth. These structures are part of a peculiar and complex neuronal circuit, composed of a chain of glomeruli organized in a necklace pattern that entirely surrounds the trunk of the olfactory bulb. We found that the necklace chain is composed of two different sets of glomeruli: one exclusively innervated by Grueneberg ganglion neurons, the other by axonal inputs from the main olfactory neuroepithelium. Combining the transgenic Grueneberg reporter mouse with a conditional null genetic approach, we then show that the axonal wiring of Grueneberg neurons is dependent on neuropilin 1 expression. Neuropilin 1-deficient Grueneberg axonal projections lose their strict and characteristic avoidance of vomeronasal glomeruli, glomeruli that are innervated by secondary neurons expressing the repulsive guidance cue and main neuropilin 1 ligand Sema3a. Taken together, our observations represent a first step in the understanding of the circuitry and the coding strategy used by the Grueneberg system. 相似文献
996.
Previously, it was reported that like land plants, the green alga Klebsormidium flaccidum (Streptophyta) accumulates sucrose during cold acclimation (Nagao et al. Plant Cell Environ 31:872–885, 2008), suggesting that synthesis of sucrose could enhance the freezing tolerance of this alga. Because sucrose phosphate phosphatase
(SPP; EC 3.1.3.24) is a key enzyme in the sucrose synthesis pathway in plants, we analyzed the SPP gene in K. flaccidum (KfSPP, GenBank accession number AB669024) to clarify its role in sucrose accumulation. As determined from its deduced amino acid
sequence, KfSPP contains the N-terminal domain that is characteristic of the L-2-haloacid-dehalogenase family of phosphatases/hydrolases
(the HAD phosphatase domain). However, it lacks the extensive C-terminal domain found in SPPs of land plants. Database searches
revealed that the SPPs in cyanobacteria also lack the C-terminal domain. In addition, the green alga Coccomyxa (Chlorophyta) and K. flaccidum, which are closely related to land plants, have cyanobacterial-type SPPs, while Chlorella (Chlorophyta) has a land plant-type SPP. These results demonstrate that even K. flaccidum (Streptophyta), as a recent ancestor of land plants, has the cyanobacterial-type SPP lacking the C-terminal domain. Because
SPP and sucrose phosphate synthase (SPS) catalyze sequential reactions in sucrose synthesis in green plant cells and the lack
of the C-terminal domain in KfSPP is predicted to decrease its activity, the interaction between decreased KfSPP activity
and SPS activity may alter sucrose synthesis during cold acclimation in K. flaccidum. 相似文献
997.
Cycad seed consumption by the native islanders of Guam is frequently associated with high rates of amyotrophic lateral sclerosis-parkinsonism
dementia complex (ALS/PDC); furthermore, accompanying pathological examination often exhibits α-synuclein inclusions in the
neurons of the affected brain. Acylated steryl-β-glucoside (ASG) contained in cycad seeds is considered as causative environmental
risk factor. We aimed to investigate whether ASG influences aggregation and cell toxicity of α-synuclein. To understand whether
ASG is a causative factor in the development of ALS/PDC, soybean-derived ASG was tested for its effect on in vitro aggregation
of α-synuclein using Thioflavin-T. ASG was also tested to determine whether it modulates α-synuclein cytotoxicity in yeast
cells. In addition, we determined whether an interaction between ASG and α-synuclein occurs in the plasma membrane or cytoplasm
using three factors: GM1 ganglioside, small unilamellar vesicles, and ATP. In the present study, we found that ASG-mediated
acceleration of α-synuclein aggregation is influenced by the presence of ATP, but not by the presence of GM1. ASG accelerated
the α-synuclein aggregation in the cytoplasm. ASG also enhanced α-synuclein-induced cytotoxicity in yeast cells. This study
demonstrated that ASG directly enhances aggregation and cytotoxicity of α-synuclein, which are often observed in patients
with ALS/PDC. These results, using assays that replicate cytoplasmic conditions, are consistent with the molecular mechanism
that cytotoxicity is caused by intracellular α-synuclein fibril formation in neuronal cells. 相似文献
998.
Tatsuo Nehira Kaoru Ishihara Koichi Matsuo Shunsuke Izumi Takeshi Yamazaki Atsuhiko Ishida 《Analytical biochemistry》2012,430(2):179-184
We report an improved fluorescence-detected circular dichroism (FDCD)-based analytical method that is useful for probing protein three-dimensional structures. The method uses a novel FDCD device with an ellipsoidal mirror that functions on a standard circular dichroism (CD) spectrometer and eliminates all artifacts. Our experiments demonstrated three important findings. First, the method is applicable to any proteins either by using intrinsic fluorescence derived from tryptophan residues or by introducing a fluorescent label onto nonfluorescent proteins. Second, by using intrinsic fluorescence, FDCD spectroscopy can detect a structural change in the tertiary structure of metmyoglobin due to stepwise denaturation on a change in pH. Such changes could not be detected by conventional CD spectroscopy. Third, based on the typical advantages of fluorescence-based analyses, FDCD measurements enable observation of only the target proteins in a solution even in the presence of other peptides. Using our ellipsoidal mirror FDCD device, we could observe structural changes of fluorescently labeled calmodulin on binding with Ca2+ and/or interacting with binding peptides. Because FDCD appears to reflect the protein’s local structure around the fluorophore, it may provide a useful means for “pinpoint analysis” of protein structures. 相似文献
999.
Arruda DC Santos LC Melo FM Pereira FV Figueiredo CR Matsuo AL Mortara RA Juliano MA Rodrigues EG Dobroff AS Polonelli L Travassos LR 《The Journal of biological chemistry》2012,287(18):14912-14922
Complementarity-determining regions (CDRs) from monoclonal antibodies tested as synthetic peptides display anti-infective and antitumor activities, independent of the specificity of the native antibody. Previously, we have shown that the synthetic peptide C7H2, based on the heavy chain CDR 2 from monoclonal antibody C7, a mAb directed to a mannoprotein of Candida albicans, significantly reduced B16F10 melanoma growth and lung colony formation by triggering tumor apoptosis. The mechanism, however, by which C7H2 induced apoptosis in tumor cells remained unknown. Here, we demonstrate that C7H2 interacts with components of the tumor cells cytoskeleton, being rapidly internalized after binding to the tumor cell surface. Mass spectrometry analysis and in vitro validation revealed that β-actin is the receptor of C7H2 in the tumor cells. C7H2 induces β-actin polymerization and F-actin stabilization, linked with abundant generation of superoxide anions and apoptosis. Major phenotypes following peptide binding were chromatin condensation, DNA fragmentation, annexin V binding, lamin disruption, caspase 8 and 3 activation, and organelle alterations. Finally, we evaluated the cytotoxic efficacy of C7H2 in a panel of human tumor cell lines. All tumor cell lines studied were equally susceptible to C7H2 in vitro. The C7H2 amide without further derivatization significantly reduced lung metastasis of mice endovenously challenged with B16F10-Nex2 melanoma cells. No significant cytotoxicity was observed toward nontumorigenic cell lines on short incubation in vitro or in naïve mice injected with a high dose of the peptide. We believe that C7H2 is a promising peptide to be developed as an anticancer drug. 相似文献
1000.
Tojo T Spears GW Tsuji K Nishimura H Ogino T Seki N Sugiyama A Matsuo M 《Bioorganic & medicinal chemistry letters》2002,12(17):2427-2430
A series of quinoline-3-carbothioamides and their analogues was prepared via four synthetic routes and evaluated for their antinephritic and immunomodulating activities. The optimal compound 9g strongly inhibited the T-cell independent antibody production in mice immunized with TNP-LPS and was highly effective in two nephritis models, namely chronic graft-versus-host disease and autoimmune MRL/l mice. 相似文献