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921.
Congde Huo Huanjie Yang Qiuzhi Cindy Cui Q. Ping Dou Tak Hang Chan 《Bioorganic & medicinal chemistry》2010,18(3):1252-1258
A pro-drug 8 of a synthetic analog 7 is more active in its antiproliferative activity against human breast cancer MDA-MB-231 cells possessing high catechol-O-methyltransferase (COMT) activity than the pro-drugs of EGCG and the analog 5. The higher activity of 8 is attributed to it not being a substrate of COMT. 相似文献
922.
Rentsenkhand Tserennadmid Miklós Takó László Galgóczy Tamás Papp Csaba Vágvölgyi László Gerő Judit Krisch 《Central European Journal of Biology》2010,5(5):641-648
The antibacterial effect of essential oils (EOs) derived from Citrus lemon, Juniperus communis, Origanum majorana, and Salvia sclarea, was investigated either alone or in combination, on 2 food related bacteria (Bacillus cereus and Escherichia coli). The influence of food ingredients — hydrolyzed proteins originating from animal and plant (meat extract and soy peptone)
and sucrose — on the antibacterial effect of EOs was also tested. The most effective antibacterial activities were obtained
with marjoram and clary sage oil, alone and in combination. High concentration of meat extract protected the bacteria from
the growth inhibiting effect of marjoram oil, while soy peptone had no such effect. Sucrose intensified the lag phase lengthening
by marjoram oil in a dose-independent manner. 相似文献
923.
TGF-beta is known to play a major role for the reduced NKG2D expression seen in cancer patients. However, the mechanisms for reduced TGF-beta-induced down-regulation of NKG2D are unclear. In this study, we observed that IL-2/IL-18 increased the NKG2D expression in the TGF-beta treated NK cell line in a dose-dependent manner. Incubation with the JNK inhibitor SP600125 inhibited the NKG2D expression induced by IL-2/IL-18 in the TGF-beta treated human NK cell line. Moreover, the NK cytotoxicity assay showed that the reduced NK cytotoxicity by TGF-beta was recovered by IL-2/IL-18 treatment. The results indicate that IL-2/IL-18 strongly prevented the TGF-beta-induced NKG2D down-regulation in NK cells via the JNK pathway. Taken together, the protected expression of NKG2D by IL-2/IL-18 provides insight into the mechanism of NKG2D regulation and it also supplied useful information for creating a novel therapeutic approach to treat TGF-beta-secreting cancer cells. 相似文献
924.
Non acetal-type derivatives at C-12 of artemisinin and their novel dimers including a fullerene conjugate were synthesized and some of them showed potent in vivo antiangiogenic activity on chorioallantoic membrane higher than or comparable to those of fumagillin and thalidomide. 相似文献
925.
We provide an experimental demonstration of positive rheotaxis (rapid and continuous upstream motility) in wild-type Escherichia coli freely swimming over a surface. This hydrodynamic phenomenon is dominant below a critical shear rate and robust against Brownian motion and cell tumbling. We deduce that individual bacteria entering a flow system can rapidly migrate upstream (>20 μm/s) much faster than a gradually advancing biofilm. Given a bacterial population with a distribution of sizes and swim speeds, local shear rate near the surface determines the dominant hydrodynamic mode for motility, i.e., circular or random trajectories for low shear rates, positive rheotaxis for moderate flow, and sideways swimming at higher shear rates. Faster swimmers can move upstream more rapidly and at higher shear rates, as expected. Interestingly, we also find on average that both swim speed and upstream motility are independent of cell aspect ratio. 相似文献
926.
Frykman S Teranishi Y Hur JY Sandebring A Yamamoto NG Ancarcrona M Nishimura T Winblad B Bogdanovic N Schedin-Weiss S Kihara T Tjernberg LO 《Neurochemistry international》2012,61(1):108-118
Synaptic degeneration is one of the earliest hallmarks of Alzheimer disease (AD) and results in loss of cognitive function. One of the causative agents for the synaptic degeneration is the amyloid β-peptide (Aβ), which is formed from its precursor protein by two sequential cleavages mediated by β- and γ-secretase. We have earlier shown that γ-secretase activity is enriched in synaptic compartments, suggesting that the synaptotoxic Aβ is produced locally. Proteins that interact with γ-secretase at the synapse and regulate the production of Aβ can therefore be potential therapeutic targets. We used a recently developed affinity purification approach to identify γ-secretase associated proteins (GSAPs) in synaptic membranes and synaptic vesicles prepared from rat brain. Liquid chromatography-tandem mass spectrometry analysis of the affinity purified samples revealed the known γ-secretase components presenilin-1, nicastrin and Aph-1b along with a number of novel potential GSAPs. To investigate the effect of these GSAPs on APP processing, we performed siRNA experiments to knock down the expression of the GSAPs and measured the Aβ levels. Silencing of NADH dehydrogenase [ubiquinone] iron-sulfur protein 7 (NDUFS7) resulted in a decrease in Aβ levels whereas silencing of tubulin polymerization promoting protein (TPPP) resulted in an increase in Aβ levels. Treatment with γ-secretase inhibitors often results in Notch-related side effects and therefore we also studied the effect of the siRNAs on Notch processing. Interestingly, silencing of TPPP or NDUFS7 did not affect cleavage of Notch. We also studied the expression of TPPP and NDUFS7 in control and AD brain and found NDUFS7 to be highly expressed in vulnerable neurons such as pyramidal neurons in the hippocampus, whereas TPPP was found to accumulate in intraneuronal granules and fibrous structures in hippocampus from AD cases. In summary, we here report on two proteins, TPPP and NDUFS7, which interact with γ-secretase and alter the Aβ levels without affecting Notch cleavage. 相似文献
927.
Takács T 《Acta biologica Hungarica》2012,63(Z1):19-37
Postnatal development of the cerebellum lasts for weeks in rodents and can be disturbed by systemic 5-bromo-2'-deoxyuridine (BrdU) administration. This thymidine analogue incorporates into the DNA of proliferating cells, and result in more or less serious damage or death granule cells, the most actively dividing neuronal population in the developing cerebellar cortex. Further consequences of postnatal BrdU administration are the interrupted postnatal migration and integrations as well as partial loss of cerebellar Purkinje cells. In the present study, C57B16 mice were administered with 50 μg/g body weight BrdU, one sc. injection daily, between P0 and P11 postnatal days, respectively.Large "cavities" appeared in the cytoplasm of a subpopulation of Purkinje cells by P7 in about one-third of administered animals, their number are size of the cavities (and PCs exhibiting unusual morphology) decreased. EM studies revealed that the unusual Purkinje cells received numerous axonal inputs of unknown origin, first of all on their somatic and dendritic spines. The transitory appearance of a subpopulation of Purkinje cells possessing unusual morphology refers to the influence of other (neuronal, glial, or both) cells on their regular differentiation. 相似文献
928.
929.
Hur YJ Yi YB Lee JH Chung YS Jung HW Yun DJ Kim KM Park DS Kim DH 《Molecular biology reports》2012,39(5):5883-5888
The ubiquitin-26S proteasome system is important in the quality control of intracellular proteins. The ubiquitin-26S proteasome
system includes the E1 (ubiquitin activating), E2 (ubiquitin conjugating), and E3 (ubiquitin ligase) enzymes. U-box proteins
are a derived version of RING-finger domains, which have E3 enzyme activity. Here, we present the isolation of a novel U-box
protein, U-box containing E3 ligase induced by phosphate starvation (OsUPS), from rice (Oryza sativa). The cDNA encoding the O. sativa U-box protein (OsUPS) comprises 1338 bp, with an open reading frame of 445 amino acids. The amino acid sequence of OsUPS
cDNA shows 41–79% identity with other plant U-box homologous genes. The open reading frame of the OsUPS protein is comprised
of notable domains: a single ~70-amino acid domain and a GKL domain that contains conserved glycine, lysine/arginine residues
and leucine-rich feature. We found that full-length expression of OsUPS was up-regulated in both rice plants and cell culture
in the absence of inorganic phosphate (Pi). A self-ubiquitination assay indicated that the bacterially expressed OsUPS protein had E3 ligase activity, and subcellular
localization results showed that OsUPS was located in the chloroplast. These results support the notion that OsUPS plays an
important role in the Pi signaling pathway through the ubiquitin-26S proteasome system. 相似文献
930.
Isolation and characterization of a non-reducing polyketide synthase gene from the lichen-forming fungus Usnea longissima 总被引:1,自引:0,他引:1
Yi Wang Jung A Kim Yong Hwa Cheong Young Jin Koh Jae-Seoun Hur 《Mycological Progress》2012,11(1):75-83
Usnea longissima has long been used as a traditional medicine in China, India, Turkey, Canada and Europe. This lichen can produce several
bioactive compounds that primarily belong to the polyketide family. The enzymes responsible for the production of these compounds
are the polyketide synthases, but the biosynthetic processes in lichens are still unclear. In this study, a cultured mycobiont
of Usnea longissima was used to isolate and characterize a polyketide synthase gene (UlPKS1). Complete sequence information regarding UlPKS1 (6,468 bp) was obtained by screening a Fosmid genomic library using a 512-bp fragment corresponding to part of the ketosynthase
(KS) domain. Sequence analysis of UlPKS1 suggested that it contained features of a non-reducing fungal type I PKS with a starter unit of ACP transacylase (SAT), ketosynthase
(KS), product template (PT), acyl carrier protein (ACP) transacylase, acyltransferase (AT) and thioesterase (TE) domain, and
had five intervening introns. The domain organization of UlPKS1 (SAT-KS-AT-PT-ACP-ACP-TE) was quite similar to that of aromatic
PKSs, and phylogenetic analysis showed that UlPKS1 belonged to the clade of lichenized fungal non-reducing PKS. RT-PCR analyses revealed that the expression of UlPKS1 was down-regulated by glycine and high concentrations of sorbitol, inositol and fructose and up-regulated by sucrose and
glucose. Here, we introduce a non-reducing PKS gene in the lichen-forming fungus U. longissima, with a domain structure similar to the structure of orsellinic acid synthase A (OrsA) which is required for orsellinic acid biosynthesis in Aspergillus nidulans. 相似文献