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181.
Profilin‐1 (Pfn1), a ubiquitously expressed actin‐binding protein, has gained interest in epithelial‐derived cancer because of its downregulation in expression in various adenocarcinoma. Pfn1 overexpression impairs tumorigenic ability of human breast cancer xenografts thus suggesting that Pfn1 could be a tumor‐suppressor protein. The objective of the present study was to determine how Pfn1 overexpression affects cell‐cycle progression of breast cancer cells. We show that Pfn1 overexpression in MDA‐MB‐231 breast cancer cells causes cell‐cycle arrest in G1 phase and dramatically reduced proliferation in culture. Pfn1 overexpression results in increased protein stability of p27kip1 (p27—a major cyclin‐dependent kinase inhibitor) and marked elevation in the overall cellular level of p27. Proliferation defect of Pfn1 overexpressers can be partly rescued by silencing p27 expression thus suggesting a critical role of p27 in Pfn1‐induced growth inhibition of MDA‐MB‐231 cells. Finally, Pfn1 overexpression was found to sensitize MDA‐MB‐231 cells to apoptosis in response to cytotoxic stimulus thus suggesting for the first time that survival of breast cancer cells can also be negatively influenced by Pfn1 upregulation. These findings may provide novel insights underlying Pfn1's tumor‐suppressive action. J. Cell. Physiol. 223:623–629, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
182.
该文利用FIASCO法(fast isolation by AFLP of sequences containing repeats)和GenBank数据库搜索法开发花鲈微卫星标记,并对筛选的标记进行多态性检测.两种方法共获得54条能够设计引物的序列,扩增结果显示15对引物具有多态性,多态性微卫星位点的等位基因数为2~10个.15个多态性位点中,4个位点偏离了Hardy-Weinberg平衡;各位点间没有连锁不平衡现象;仅位点SP52可能存在无效等位基因;除SP17和SP468外,其余引物的P1C值均在0.5以上,可用于花鲈群体遗传分析等研究. 相似文献
183.
Liang Zhang Zhongyang Ding Peng Xu Yuhong Wang Zhenghua Gu Zhu Qian Guiyang Shi Kechang Zhang 《Biotechnology and Bioprocess Engineering》2011,16(3):457-461
Tyrosinase is a key enzyme in the biosynthesis of melanin, and the use of inhibitors against tyrosinase can prevent hyperpigmentation
by inhibiting enzymatic oxidation. However, the current use of tyrosine inhibitors is limited by their low activities and
high toxicities. The aim of the present research was to develop novel whitening agents, or tyrosinase-targeted medicine, from
a submerged culture of the fungus Ganoderma lucidum. Methyl lucidenate F was isolated from the ethanol-soluble-acidic components (ESACs) of G. lucidum, with the structure of ESACs elucidated via UV, LC-MS, and 13C-NMR spectral analysis. The tyrosinase inhibitory activity was measured using catechol as a substrate. Methyl lucidenate
F displayed uncompetitive inhibition of the potato tyrosinase activity, for which Lineweaver-Burk plots revealed a maximum
reaction rate (V
max) of 0.4367/min, Michaelis constant (K
m) of 6.765 mM and uncompetitive inhibition constant (K
i) of 19.22 μM. Meanwhile, methyl lucidenate F (tetra cyclic triterpenoid) exhibited high tyrosinase inhibitory activity, with
an IC50 of 32.23 μM. These results suggest that methyl lucidenate F may serve as a potential candidate for skin-whitening agents. 相似文献
184.
A hidden aggregation‐prone structure in the heart of hypoxia inducible factor prolyl hydroxylase 下载免费PDF全文
Hamid Hadi‐Alijanvand Elizabeth A. Proctor Feng Ding Nikolay V. Dokholyan Ali A. Moosavi‐Movahedi 《Proteins》2016,84(5):611-623
Prolyl hydroxylase domain‐containing protein 2 (PHD2), as one of the most important regulators of angiogenesis and metastasis of cancer cells, is a promising target for cancer therapy drug design. Progressive studies imply that abnormality in PHD2 function may be due to misfolding. Therefore, study of the PHD2 unfolding pathway paves the way for a better understanding of the influence of PHD2 mutations and cancer cell metabolites on the protein folding pathway. We study the unfolding of the PHD2 catalytic domain using differential scanning calorimetry (DSC), fluorescence spectroscopy, and discrete molecular dynamics simulations (DMD). Using computational and experimental techniques, we find that PHD2 undergoes four transitions along the thermal unfolding pathway. To illustrate PHD2 unfolding events in atomic detail, we utilize DMD simulations. Analysis of computational results indicates an intermediate species in the PHD2 unfolding pathway that may enhance aggregation propensity, explaining mutation‐independent PHD2 malfunction. Proteins 2016; 84:611–623. © 2016 Wiley Periodicals, Inc. 相似文献
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187.
Chenjun Ding Ling Qing Zhenghe Li Yi Liu Yajuan Qian Xueping Zhou 《Applied and environmental microbiology》2009,75(16):5380-5389
Begomovirus-DNA-β disease complexes induce different symptom phenotypes in their hosts. To investigate the genetic determinants of the phenotypic differences, Nicotiana spp. and tomato plants were inoculated with infectious clones of Tobacco curly shoot virus (TbCSV)/TbCSV DNA-β (TbCSB) and Tomato yellow leaf curl China virus (TYLCCNV)/TYLCCNV DNA-β (TYLCCNB) pseudorecombinants and showed that TYLCCNB induced characteristic vein-thickening and enation symptoms, while TbCSB only slightly exacerbated the leaf-curling symptoms, regardless of the helper virus being used. The roles of DNA-β-encoded βC1 and a 430-nucleotide fragment containing the A-rich region and the putative βC1 promoter region of the βC1 gene (referred to as AP) in symptom development were further investigated by constructing hybrid satellites in which the βC1 coding region or AP was exchanged between the two satellite molecules. A TYLCCNB hybrid with TbCSB βC1 lost the ability to elicit the vein-thickening and enation phenotypes. TbCSB hybrids containing the TYLCCNB βC1 or AP fragment failed to induce the characteristic vein thickening and enations. A TYLCCNB hybrid having the TbCSB AP fragment produced the enations, but the number of enations was less and their sizes were reduced. Differently from the phloem-specific pattern of the TYLCCNB promoter, a full-length fragment upstream of the TbCSB βC1 gene confers a constitutive β-glucuronidase expression pattern in transgenic tobacco plants. The above results indicate that the DNA-β-encoded βC1 protein is the symptom determinant, but the promoter of the βC1 gene has influence on symptom production.Geminiviruses are small plant viruses with circular single-stranded DNA (ssDNA) genomes that are encapsidated in unique twinned (geminate) particles. Members of the genus Begomovirus are transmitted by whiteflies (Bemisia tabaci) and infect dicotyledonous plants (42). Begomoviruses have either one or two circular ssDNA genomic components (DNA-A and DNA-B). The DNA-A component is capable of autonomous replication and encapsidation, whereas the DNA-B component encodes two proteins (BC1 and BV1) involved in movement (14). Recently, some monopartite begomoviruses have been found in association with a novel satellite DNA molecule, referred to as DNA-β and now known as a betasatellite (2, 5, 20, 22, 38, 45). DNA-β is approximately half the size of the viral genomic DNA, and apart from a nonanucleotide sequence (TAATATTAC), it has little sequence identity with viral genomic DNA. DNA-β depends on the helper virus for replication and encapsidation and, in turn, is required for the induction of bona fide disease symptoms. DNA-β bears a βC1 open reading frame (ORF) on the complementary-sense strand, which is conserved among distinct betasatellites in terms of position and size. Mutational analyses and constitutive expression have shown that βC1 is a strong pathogenicity/symptom determinant (7, 34, 39).Begomovirus-DNA-β disease complexes are associated with a wide range of plant species and induce different sets of symptom phenotypes in their natural hosts (25). However, the contributions of the helper virus and the satellite molecule to symptom development are not clear. Tomato yellow leaf curl China virus (TYLCCNV) and Tobacco curly shoot virus (TbCSV) are monopartite begomoviruses associated with DNA-β, but they differ in the symptom phenotypes induced in Nicotiana spp. and Solanum lycopersicum (7, 22). In the present work, we report that the symptom differences between TYLCCNV/TYLCCNV DNA-β (TYLCCNB) and TbCSV/TbCSV DNA-β (TbCSB) are determined by DNA-β and the DNA-β-encoded βC1 protein is the symptom determinant, but the promoter of the βC1 gene has influence on symptom production. 相似文献
188.
T. Aran Mooney Songhai Li Darlene R. Ketten Kexiong Wang Ding Wang 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2011,197(12):1149-1158
Temporal cues are important for some forms of auditory processing, such as echolocation. Among odontocetes (toothed whales,
dolphins, and porpoises), it has been suggested that porpoises may have temporal processing abilities which differ from other
odontocetes because of their relatively narrow auditory filters and longer duration echolocation signals. This study examined
auditory temporal resolution in two Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis) using auditory evoked potentials (AEPs) to measure: (a) rate following responses and modulation rate transfer function for
100 kHz centered pulse sounds and (b) hearing thresholds and response amplitudes generated by individual pulses of different
durations. The animals followed pulses well at modulation rates up to 1,250 Hz, after which response amplitudes declined until
extinguished beyond 2,500 Hz. The subjects had significantly better hearing thresholds for longer, narrower-band pulses similar
to porpoise echolocation signals compared to brief, broadband sounds resembling dolphin clicks. Results indicate that the
Yangtze finless porpoise follows individual acoustic signals at rates similar to other odontocetes tested. Relatively good
sensitivity for longer duration, narrow-band signals suggests that finless porpoise hearing is well suited to detect their
unique echolocation signals. 相似文献
189.
Chen SB Tan JH Ou TM Huang SL An LK Luo HB Li D Gu LQ Huang ZS 《Bioorganic & medicinal chemistry letters》2011,21(3):1004-1009
Discovery of potent and selective ligands for telomeric G-quadruplex DNA is a challenging work. Through a combination approach of pharmacophore model construction, model validation, database virtual screening, chemical synthesis and interaction evaluation, we discovered and confirmed triaryl-substituted imidazole TSIZ01 to be a new telomeric G-quadruplex ligand with potent binding and stabilizing activity to G-quadruplex DNA, as well as a 8.7-fold selectivity towards telomeric G-quadruplex DNA over duplex DNA. 相似文献
190.
记述了中国同脉缟蝇亚属20个种团,其中17个种团,即异突同脉缟蝇种团H.(H.)abnormis group,双带同脉缟蝇种团H.(H.)bistriata group,短突同脉缟蝇种团H.(H.)brevis group,台湾同脉缟蝇种团H.(H.)formosae group,河南同脉缟蝇种团H.(H.)henanensis group,叉突同脉缟蝇种团H.(H.)laticosta group,李氏同脉缟蝇种团H.(H.)lii group,背斑同脉缟蝇种团H.(H.)notostigma group,美额同脉缟蝇种团H.(H.)ornatifrons group,多斑同脉缟蝇种团H.(H.)picta group,五斑同脉缟蝇种团H.(H.)quiquenotat group,单突同脉缟蝇种团H.(H.)singularis group,纹额同脉缟蝇种团H.(H.)striatifrons group,斑腿同脉缟蝇种团H.(H.)substigmata group,西藏同脉缟蝇种团H.(H.)tibetensis group,三尖同脉缟蝇种团H.(H.)trispina group,爪突同脉缟蝇种团日.(H.)unguiculata group为首次提出,并描述了2新种,平截同脉缟蝇H.(H.)trunciformis sp.nov.和长膜同脉缟蝇H.(H.)longinotata sp.nov.,提供了该亚属分种团检索表.所有观察标本均保存于中国农业大学昆虫标本馆. 相似文献