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61.
Brennan JP Miller JI Fuller W Wait R Begum S Dunn MJ Eaton P 《Molecular & cellular proteomics : MCP》2006,5(2):215-225
Glutathione disulfide (GSSG) accumulates in cells under an increased oxidant load, which occurs during neurohormonal or metabolic stimulation as well as in many disease states. Elevated GSSG promotes protein S-glutathiolation, a reversible post-translational modification, which can directly alter or regulate protein function. We developed novel strategies for the study of protein S-glutathiolation that involved the simple synthesis of N,N-biotinyl glutathione disulfide (biotin-GSSG). Biotin-GSSG treatment of cells mimics a defined component of oxidative stress, namely a shift in the glutathione redox couple to the oxidized disulfide state. This induces widespread protein S-glutathiolation, which was detected on non-reducing Western blots probed with streptavidin-horseradish peroxidase and imaged using confocal fluorescence microscopy and ExtrAvidin-FITC. S-Glutathiolated proteins were purified using streptavidin-agarose and identified using proteomic methods. We conclude that biotin-GSSG is a useful tool in the investigation of protein S-glutathiolation and offers significant advantages over conventional methods or antibody-based strategies. These novel approaches may find widespread utility in the study of disease or redox signaling models where GSSG accumulation occurs. 相似文献
62.
A copper(I) complex of 2-aminobenzenethiol, [Cu(abt)]∞ (1), has been synthesized and characterized. The crystal structure determination indicates a two-dimensional metallopolymeric network formed by edge and corner sharing [Cu(μ3-S)N] coordination tetrahedra wherein the copper(I) centers are coordinated to three bridging thiolate donors and the amino group of 2-aminobenzenethiolate. The copper, the sulfur and the nitrogen atoms form sub-lattices that reveal independently striking similarities to the double-layers present in black phosphorus. 相似文献
63.
Polyamines induce rapid biosynthesis of nitric oxide (NO) in Arabidopsis thaliana seedlings 总被引:7,自引:0,他引:7
Tun NN Santa-Catarina C Begum T Silveira V Handro W Floh EI Scherer GF 《Plant & cell physiology》2006,47(3):346-354
In this study, we examined the regulation by putrescine, spermidine and spermine of nitric oxide (NO) biosynthesis in Arabidopsis thaliana seedlings. Using a fluorimetric method employing the cell-impermeable NO-binding dye diaminorhodamine-4M (DAR-4M), we observed that the polyamines (PAs) spermidine and spermine greatly increased NO release in the seedlings, whereas arginine and putrescine had little or no effect. Spermine, the most active PA, stimulated NO release with no apparent lag phase. The response was quenched by addition of 2-aminoethyl-2-thiopseudourea (AET), an inhibitor of the animal nitric oxide synthase (NOS) and plant NO biosynthesis, and by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-1-oxy-3-oxide (PTIO), an NO scavenger. By fluorescence microscopy, using the cell-permeable NO-binding dye diaminorhodamine-4M acetoxymethyl ester (DAR-4M AM), we observed that PAs induced NO biosynthesis in specific tissues in Arabidopsis seedlings. Spermine and spermidine increased NO biosynthesis in the elongation zone of the Arabidopsis root tip and in primary leaves, especially in the veins and trichomes, while in cotyledons little or no effect of PAs beyond the endogenous levels of NO-induced fluorescence was observed. We conclude that PAs induce NO biosynthesis in plants. 相似文献
64.
65.
Choudhary MI Begum A Abbaskhan A Shafiq-ur-Rehman Atta-ur-Rahman 《Carbohydrate research》2006,341(14):2398-2405
Phytochemical investigation on the whole plants of Lindelofia stylosa (Kar. and Kir.) has led to the isolation of eight fructo-oligosaccharide cinnamate esters 1-8. Six new compounds 1, 2, and 5-8 were isolated from the butanol extract of the plant. Compounds 1-4 belong to sucrose derivatives, while compounds 5-6 and 7-8 belong to 1-kestose- and nystose-type oligosaccharides, respectively. The fructo-oligosaccharides have been obtained from L. stylosa for the first time. 相似文献
66.
Kato L Stanlie A Begum NA Kobayashi M Aida M Honjo T 《Journal of immunology (Baltimore, Md. : 1950)》2012,188(8):3559-3566
An ortholog of activation-induced cytidine deaminase (AID) was, evolutionarily, the first enzyme to generate acquired immune diversity by catalyzing gene conversion and probably somatic hypermutation (SHM). AID began to mediate class switch recombination (CSR) only after the evolution of frogs. Recent studies revealed that the mechanisms for generating immune and genetic diversity share several critical features. Meiotic recombination, V(D)J recombination, CSR, and SHM all require H3K4 trimethyl histone modification to specify the target DNA. Genetic instability related to dinucleotide or triplet repeats depends on DNA cleavage by topoisomerase 1, which also initiates DNA cleavage in both SHM and CSR. These similarities suggest that AID hijacked the basic mechanism for genome instability when AID evolved in jawless fish. Thus, the risk of introducing genome instability into nonimmunoglobulin loci is unavoidable but tolerable compared with the advantage conferred on the host of being protected against pathogens by the enormous Ig diversification. 相似文献
67.
68.
69.
Microbial selection on enhanced biological phosphorus removal systems fed exclusively with glucose 总被引:1,自引:0,他引:1
The microbial selection on an enhanced biological phosphorus removal (EBPR) system was investigated in a laboratory-scale
sequencing batch reactor fed exclusively with glucose as the carbon source. Fluorescence In Situ Hybridization analysis was
performed to target two polyphosphate accumulating organisms (PAOs) (i.e., Candidatus Accumulibacter phosphatis and Microlunatus phosphovorus) and two glycogen accumulating organisms (GAOs) (i.e., Candidatus Competibacter phosphatis and Micropruina glycogenica). The results show that glucose might not select for Candidatus Accumulibacter phosphatis. However, Microlunatus phosphovorus, Candidatus Competibacter phosphatis, and Micropruina glycogenica might be selected. The highest percent relative abundance (% RA) of Candidatus Accumulibacter phosphatis was about 42%; this occurred at the beginning of the experimental period when phosphorus removal
was efficient. However, the % RA of these bacteria decreased, reaching below 4% at the end of the run. The maximum % RA of
Microlunatus phosphovorus, Candidatus Competibacter phosphatis, and Micropruina glycogenica was about 21, 37, 17%, respectively. It appears that a higher glucose concentration might be detrimental for Microlunatus phosphovorus and Micropruina glycogenica. Results also indicate a dominance of GAOs over PAOs when EBPR systems are fed with glucose. It is possible that the GAOs
outcompete the PAOs at low pH values; it has been reported that at low pH, GAOs use glycogen as the energy source to uptake
glucose. As a result, P-removal deteriorated. Therefore, glucose is not a strong candidate as a carbon source to supplement
EBPR systems that do not contain sufficient volatile fatty acids. 相似文献
70.
Han SJ Hawkins SM Begum K Jung SY Kovanci E Qin J Lydon JP DeMayo FJ O'Malley BW 《Nature medicine》2012,18(7):1102-1111
Endometriosis is considered to be an estrogen-dependent inflammatory disease, but its etiology is unclear. Thus far, a mechanistic role for steroid receptor coactivators (SRCs) in the progression of endometriosis has not been elucidated. An SRC-1-null mouse model reveals that the mouse SRC-1 gene has an essential role in endometriosis progression. Notably, a previously unidentified 70-kDa SRC-1 proteolytic isoform is highly elevated both in the endometriotic tissue of mice with surgically induced endometriosis and in endometriotic stromal cells biopsied from patients with endometriosis compared to normal endometrium. Tnf?/? and Mmp9?/? mice with surgically induced endometriosis showed that activation of tumor necrosis factor a (TNF-α)-induced matrix metallopeptidase 9 (MMP9) activity mediates formation of the 70-kDa SRC-1 C-terminal isoform in endometriotic mouse tissue. In contrast to full-length SRC-1, the endometriotic 70-kDa SRC-1 C-terminal fragment prevents TNF-α-mediated apoptosis in human endometrial epithelial cells and causes the epithelial-mesenchymal transition and the invasion of human endometrial cells that are hallmarks of progressive endometriosis. Collectively, the newly identified TNF-α-MMP9-SRC-1 isoform functional axis promotes pathogenic progression of endometriosis. 相似文献