排序方式: 共有99条查询结果,搜索用时 15 毫秒
41.
Avi Avidan Michal Perlmutter Smadar Tal Omer Oraki Tsachi Kapp Yacov Krelin Moshe Elkabets Shahar Dotan Ron N. Apte Rachel G. Lichtenstein 《Glycoconjugate journal》2009,26(9):1181-1195
We evaluated the patterns of sialylation on fibrosarcoma cell lines arising following 3-methylcholanthrene treatments of wild-type
and IL-1α-deficient mice; the former induced progressive tumors, whereas the latter cell lines induced regressing tumors or
failed to develop into tumors in mice due to immune rejection. In regressing tumors, terminating α2-6-Neu5Ac residues were
present at lower levels than in progressively growing tumors. In both tumor cells, the amount of α2-6-Neu5Ac residues was
higher by an order of magnitude relative to the amount expressed in primary fibroblasts harvested from IL-1α-deficient and
wild-type mice. We focused on membrane proteins, which may interact with the immune system. Interestingly, HSP65, grp75, and
gp96 were found on the surfaces of malignant cells and were shown to possess sialylated N-glycans. The amount of trisialylated
glycans on gp96 and HSP65 and monosialylated glycans on grp75 of regressing cells was significantly lower than in progressively
growing cells, suggesting a dependency of these specific glycoforms on anti-tumor immunity. 相似文献
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Seley Gharanei Anna T Brini Sumathi Vaiyapuri Abdullah Alholle Ashraf Dallol Elena Arrigoni Takeshi Kishida Toru Hiruma Smadar Avigad Robert Grimer Eamonn R Maher Farida Latif 《Epigenetics》2013,8(9):893-898
Ras-association domain family of genes consist of 10 members (RASSF1-RASSF10), all containing a Ras-association (RA) domain in either the C- or the N-terminus. Several members of this gene family are frequently methylated in common sporadic cancers; however, the role of the RASSF gene family in rare types of cancers, such as bone cancer, has remained largely uninvestigated. In this report, we investigated the methylation status of RASSF1A and RASSF2 in Ewing sarcoma (ES). Quantitative real-time methylation analysis (MethyLight) demonstrated that both genes were frequently methylated in Ewing sarcoma tumors (52.5% and 42.5%, respectively) as well as in ES cell lines and gene expression was upregulated in methylated cell lines after treatment with 5-aza-2′-deoxcytidine. Overexpression of either RASSF1A or RASSF2 reduced colony formation ability of ES cells. RASSF2 methylation correlated with poor overall survival (p = 0.028) and this association was more pronounced in patients under the age of 18 y (p = 0.002). These results suggest that both RASSF1A and RASSF2 are novel epigenetically inactivated tumor suppressor genes in Ewing sarcoma and RASSF2 methylation may have prognostic implications for ES patients. 相似文献
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Harpaz-Saad S McFarlane HE Xu S Divi UK Forward B Western TL Kieber JJ 《The Plant journal : for cell and molecular biology》2011,68(6):941-953
The seeds of Arabidopsis thaliana and many other plants are surrounded by a pectinaceous mucilage that aids in seed hydration and germination. Mucilage is synthesized during seed development within maternally derived seed coat mucilage secretory cells (MSCs), and is released to surround the seed upon imbibition. The FEI1/FEI2 receptor-like kinases and the SOS5 extracellular GPI-anchored protein were shown previously to act on a pathway that regulates the synthesis of cellulose in Arabidopsis roots. Here, we demonstrate that both FEI2 and SOS5 also play a role in the synthesis of seed mucilage. Disruption of FEI2 or SOS5 leads to a reduction in the rays of cellulose observed across the seed mucilage inner layer, which alters the structure of the mucilage in response to hydration. Mutations in CESA5, which disrupts an isoform of cellulose synthase involved in primary cell wall synthesis, result in a similar seed mucilage phenotype. The data indicate that CESA5-derived cellulose plays an important role in the synthesis and structure of seed coat mucilage and that the FEI2/SOS5 pathway plays a role in the regulation of cellulose synthesis in MSCs. Moreover, these results establish a novel structural role for cellulose in anchoring the pectic component of seed coat mucilage to the seed surface. 相似文献
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Eric Aslakson Smadar Szekely Suzanne D Vernon Lucinda Bateman Jan Baumbach Yaki Setty 《Theoretical biology & medical modelling》2012,9(1):1-15
Background
Consensus exists that several bariatric surgery procedures produce a rapid improvement of glucose homeostasis in obese diabetic patients, improvement apparently uncorrelated with the degree of eventual weight loss after surgery. Several hypotheses have been suggested to account for these results: among these, the anti-incretin, the ghrelin and the lower-intestinal dumping hypotheses have been discussed in the literature. Since no clear-cut experimental results are so far available to confirm or disprove any of these hypotheses, in the present work a mathematical model of the glucose-insulin-incretin system has been built, capable of expressing these three postulated mechanisms. The model has been populated with critically evaluated parameter values from the literature, and simulations under the three scenarios have been compared.Results
The modeling results seem to indicate that the suppression of ghrelin release is unlikely to determine major changes in short-term glucose control. The possible existence of an anti-incretin hormone would be supported if an experimental increase of GIP concentrations were evident post-surgery. Given that, on the contrary, collected evidence suggests that GIP concentrations decrease post-surgery, the lower-intestinal dumping hypothesis would seem to describe the mechanism most likely to produce the observed normalization of Type 2 Diabetes Mellitus (T2DM) after bariatric surgery.Conclusions
The proposed model can help discriminate among competing hypotheses in a context where definitive data are not available and mechanisms are still not clear. 相似文献47.
Santosh K. Dasari Eyal Schejter Shani Bialik Aya Shkedy Vered Levin-Salomon Smadar Levin-Zaidman 《Cell cycle (Georgetown, Tex.)》2017,16(21):2003-2010
Autophagy is critical for homeostasis and cell survival during stress, but can also lead to cell death, a little understood process that has been shown to contribute to developmental cell death in lower model organisms, and to human cancer cell death. We recently reported1 on our thorough molecular and morphologic characterization of an autophagic cell death system involving resveratrol treatment of lung carcinoma cells. To gain mechanistic insight into this death program, we performed a signalome-wide RNAi screen for genes whose functions are necessary for resveratrol-induced death. The screen identified GBA1, the gene encoding the lysosomal enzyme glucocerebrosidase, as an important mediator of autophagic cell death. Here we further show the physiological relevance of GBA1 to developmental cell death in midgut regression during Drosophila metamorphosis. We observed a delay in midgut cell death in two independent Gba1a RNAi lines, indicating the critical importance of Gba1a for midgut development. Interestingly, loss-of-function GBA1 mutations lead to Gaucher Disease and are a significant risk factor for Parkinson Disease, which have been associated with defective autophagy. Thus GBA1 is a conserved element critical for maintaining proper levels of autophagy, with high levels leading to autophagic cell death. 相似文献
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Shulami S Yaniv O Rabkin E Shoham Y Baasov T 《Extremophiles : life under extreme conditions》2003,7(6):471-481
3-Deoxy-d-manno-2-octulosonate-8-phosphate (KDO8P) synthase, catalyzes the aldol-type condensation between phosphoenolpyruvate (PEP) and d-arabinose-5-phosphate (A5P) to produce the unusual 8-carbon sugar KDO8P, and inorganic phosphate. A 15.5-kb segment containing the kdsA gene from the hyperthermophilic bacterium Aquifex pyrophilus was cloned from a genomic library and sequenced. The native kdsA gene lacks a typical ribosome binding site, but contains a conserved U,A-rich sequence upstream to the start codon. The purified kdsA gene product catalyzes the formation of KDO8P from its natural substrates, PEP and A5P, as determined by 1H NMR analysis. KDO8P synthase showed maximum activity at 80 °C and pH 5.5–6.0 at 10-min reaction assay. At temperatures of 70, 80, and 90 °C, the enzyme exhibited half-lives of 8.0, 2.25, and 0.5 h, respectively. The kinetic constants at 60 °C were KmA5P=70 M, KmPEP=290 M, and kcat=4 s–1. The isolated enzyme contained 0.19 and 0.26 mol iron and zinc, respectively, per mole of enzyme subunit. Treatment with metal chelators eliminated enzyme activity, and by the addition of several divalent metal ions, the activity was restored and even exceeded the original activity. These results indicate that A. pyrophilus KDO8P synthase is a metal-dependent enzyme. A C11A mutant of KDO8P synthase from A. pyrophulis retained less than 1% of the wild-type activity and was shown to be incapable of metal binding.Communicated by G. Antranikian 相似文献
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