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991.
Roy SK Chandra K Ghosh K Mondal S Maiti D Ojha AK Das D Mondal S Chakraborty I Islam SS 《Carbohydrate research》2007,342(16):2380-2389
A water-soluble polysaccharide was isolated from the aqueous extract of pods of Moringa oleifera. The polysaccharide contains d-galactose, 6-O-Me-D-galactose, D-galacturonic acid, l-arabinose, and l-rhamnose in a molar ratio of 1:1:1:1:1. On the basis of total hydrolysis, methylation analysis, periodate oxidation, and NMR ((1)H, (13)C, TOCSY, DQF-COSY, NOESY, ROESY, HSQC, and HMBC) studies, the repeating unit of the polysaccharide is established as [structure: see text]. 相似文献
992.
Flux Analysis of Central Metabolic Pathways in Geobacter metallireducens during Reduction of Soluble Fe(III)-Nitrilotriacetic Acid
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Yinjie J. Tang Romy Chakraborty Hctor García Martín Jeannie Chu Terry C. Hazen Jay D. Keasling 《Applied microbiology》2007,73(12):3859-3864
We analyzed the carbon fluxes in the central metabolism of Geobacter metallireducens strain GS-15 using 13C isotopomer modeling. Acetate labeled in the first or second position was the sole carbon source, and Fe-nitrilotriacetic acid was the sole terminal electron acceptor. The measured labeled acetate uptake rate was 21 mmol/g (dry weight)/h in the exponential growth phase. The resulting isotope labeling pattern of amino acids allowed an accurate determination of the in vivo global metabolic reaction rates (fluxes) through the central metabolic pathways using a computational isotopomer model. The tracer experiments showed that G. metallireducens contained complete biosynthesis pathways for essential metabolism, and this strain might also have an unusual isoleucine biosynthesis route (using acetyl coenzyme A and pyruvate as the precursors). The model indicated that over 90% of the acetate was completely oxidized to CO2 via a complete tricarboxylic acid cycle while reducing iron. Pyruvate carboxylase and phosphoenolpyruvate (PEP) carboxykinase were present under these conditions, but enzymes in the glyoxylate shunt and malic enzyme were absent. Gluconeogenesis and the pentose phosphate pathway were mainly employed for biosynthesis and accounted for less than 3% of total carbon consumption. The model also indicated surprisingly high reversibility in the reaction between oxoglutarate and succinate. This step operates close to the thermodynamic equilibrium, possibly because succinate is synthesized via a transferase reaction, and the conversion of oxoglutarate to succinate is a rate-limiting step for carbon metabolism. These findings enable a better understanding of the relationship between genome annotation and extant metabolic pathways in G. metallireducens. 相似文献
993.
Heavy metal content analysis of River Torsa in India did not indicate any alarming level of toxicity for human consumption
but revealed variation at the ppb level in different months. The variation in recoverable nickel and zinc resistant copiotrophic
(or eutrophic) bacterial counts was explained by the variation of the zinc content (34.0–691.3 ppb) of the river water in
different sampling months. Growth studies conducted with some purified nickel and/or zinc resistant strains revealed that
pre-exposure of the cells to ppb levels of Zn2+, comparable to the indigenous zinc ion concentration of the river, could induce the nickel or zinc resistance. A minimum
concentration of 5–10 μM Zn2+ (325–650 ppb) was found effective in inducing the Nickel resistance of the isolates. Zinc resistance of the isolates was tested
by pre-exposing the cells to 4 μM Zn2+ (260 ppb). The lag phase was reduced by 6–8 h in all the cases. Biochemical characteristics and phylogenetic analysis based
on 16S rDNA sequence indicated that some of the Torsa River isolates, having inducible nickel and zinc resistance, are members
of the genus Pseudomonas, Acinetobacter, Bacillus, Enterobacter, Serratia and Moraxella. 相似文献
994.
Tang YJ Chakraborty R Martín HG Chu J Hazen TC Keasling JD 《Applied and environmental microbiology》2007,73(12):3859-3864
We analyzed the carbon fluxes in the central metabolism of Geobacter metallireducens strain GS-15 using 13C isotopomer modeling. Acetate labeled in the first or second position was the sole carbon source, and Fe-nitrilotriacetic acid was the sole terminal electron acceptor. The measured labeled acetate uptake rate was 21 mmol/g (dry weight)/h in the exponential growth phase. The resulting isotope labeling pattern of amino acids allowed an accurate determination of the in vivo global metabolic reaction rates (fluxes) through the central metabolic pathways using a computational isotopomer model. The tracer experiments showed that G. metallireducens contained complete biosynthesis pathways for essential metabolism, and this strain might also have an unusual isoleucine biosynthesis route (using acetyl coenzyme A and pyruvate as the precursors). The model indicated that over 90% of the acetate was completely oxidized to CO2 via a complete tricarboxylic acid cycle while reducing iron. Pyruvate carboxylase and phosphoenolpyruvate (PEP) carboxykinase were present under these conditions, but enzymes in the glyoxylate shunt and malic enzyme were absent. Gluconeogenesis and the pentose phosphate pathway were mainly employed for biosynthesis and accounted for less than 3% of total carbon consumption. The model also indicated surprisingly high reversibility in the reaction between oxoglutarate and succinate. This step operates close to the thermodynamic equilibrium, possibly because succinate is synthesized via a transferase reaction, and the conversion of oxoglutarate to succinate is a rate-limiting step for carbon metabolism. These findings enable a better understanding of the relationship between genome annotation and extant metabolic pathways in G. metallireducens. 相似文献
995.
Kumar Surarapu Lava Singh Ravinder Gurao Ankita Mishra S. K. Kumar Prem Vohra Vikas Niranjan Saket Kumar Sodhi Monika Dash S. K. Sarangdhar S. Mukesh Manishi Kataria Ranjit Singh 《Molecular biology reports》2022,49(7):6029-6040
Molecular Biology Reports - India has a vast riverine and swamp buffalo diversity adapted to various agro-ecological conditions. In the present study, genetic diversity data for 10 different... 相似文献
996.
Anirban Chakraborty Maki Wakamiya Tatiana Venkova-Canova Raj K. Pandita Leopoldo Aguilera-Aguirre Altaf H. Sarker Dharmendra Kumar Singh Koa Hosoki Thomas G. Wood Gulshan Sharma Victor Cardenas Partha S. Sarkar Sanjiv Sur Tej K. Pandita Istvan Boldogh Tapas K. Hazra 《The Journal of biological chemistry》2015,290(41):24636-24648
997.
A Novel Role for Protein Kinase Kin2 in Regulating HAC1 mRNA Translocation,Splicing, and Translation
Ashish Anshu M. Amin-ul Mannan Abhijit Chakraborty Saikat Chakrabarti Madhusudan Dey 《Molecular and cellular biology》2015,35(1):199-210
A signaling network called the unfolded protein response (UPR) resolves the protein-folding defects in the endoplasmic reticulum (ER) from yeasts to humans. In the yeast Saccharomyces cerevisiae, the UPR activation involves (i) aggregation of the ER-resident kinase/RNase Ire1 to form an Ire1 focus, (ii) targeting HAC1 pre-mRNA toward the Ire1 focus that cleaves out an inhibitory intron from the mRNA, and (iii) translation of Hac1 protein from the spliced mRNA. Targeting HAC1 mRNA to the Ire1 focus requires a cis-acting bipartite element (3′BE) located at the 3′ untranslated leader. Here, we report that the 3′BE plays an additional role in promoting translation from the spliced mRNA. We also report that a high dose of either of two paralogue kinases, Kin1 and Kin2, overcomes the defective UPR caused by a mutation in the 3′BE. These results define a novel role for Kin kinases in the UPR beyond their role in cell polarity and exocytosis. Consistently, targeting, splicing, and translation of HAC1 mRNA are substantially reduced in the kin1Δ kin2Δ strain. Furthermore, we show that Kin2 kinase domain itself is sufficient to activate the UPR, suggesting that Kin2 initiates a signaling cascade to ensure an optimum UPR. 相似文献
998.
Pei-Yu Wang Wei-Cheng Lin Yi-Cheng Tsai Mei-Ling Cheng Yu-Hung Lin Shu-Heng Tseng Archan Chakraborty Li-Mei Pai 《Genetics》2015,201(4):1511-1523
CTP synthase (CTPsyn) plays an essential role in DNA, RNA, and lipid synthesis. Recent studies in bacteria, yeast, and Drosophila all reveal a polymeric CTPsyn structure, which dynamically regulates its enzymatic activity. However, the molecular mechanism underlying the formation of CTPsyn polymers is not completely understood. In this study, we found that reversible ubiquitination regulates the dynamic assembly of the filamentous structures of Drosophila CTPsyn. We further determined that the proto-oncogene Cbl, an E3 ubiquitin ligase, controls CTPsyn filament formation in endocycles. While the E3 ligase activity of Cbl is required for CTPsyn filament formation, Cbl does not affect the protein levels of CTPsyn. It remains unclear whether the regulation of CTPsyn filaments by Cbl is through direct ubiquitination of CTPsyn. In the absence of Cbl or with knockdown of CTPsyn, the progression of the endocycle-associated S phase was impaired. Furthermore, overexpression of wild-type, but not enzymatically inactive CTPsyn, rescued the endocycle defect in Cbl mutant cells. Together, these results suggest that Cbl influences the nucleotide pool balance and controls CTPsyn filament formation in endocycles. This study links Cbl-mediated ubiquitination to the polymerization of a metabolic enzyme and reveals a role for Cbl in endocycles during Drosophila development. 相似文献
999.
Haiming Xu Nikolay L. Malinin Niranjan Awasthi Roderich E. Schwarz Margaret A. Schwarz 《The Journal of biological chemistry》2015,290(15):9753-9766
Pro-endothelial monocyte-activating polypeptide II (EMAP II), one component of the multi-aminoacyl tRNA synthetase complex, plays multiple roles in physiological and pathological processes of protein translation, signal transduction, immunity, lung development, and tumor growth. Recent studies have determined that pro-EMAP II has an essential role in maintaining axon integrity in central and peripheral neural systems where deletion of the C terminus of pro-EMAP II has been reported in a consanguineous Israeli Bedouin kindred suffering from Pelizaeus-Merzbacher-like disease. We hypothesized that the N terminus of pro-EMAP II has an important role in the regulation of protein-protein interactions. Using a GFP reporter system, we defined a putative leucine zipper in the N terminus of human pro-EMAP II protein (amino acid residues 1–70) that can form specific strip-like punctate structures. Through GFP punctum analysis, we uncovered that the pro-EMAP II C terminus (amino acids 147–312) can repress GFP punctum formation. Pulldown assays confirmed that the binding between the pro-EMAP II N terminus and its C terminus is mediated by a putative leucine zipper. Furthermore, the pro-EMAP II 1–70 amino acid region was identified as the binding partner of arginyl-tRNA synthetase, a polypeptide of the multi-aminoacyl tRNA synthetase complex. We also determined that the punctate GFP pro-EMAP II 1–70 amino acid aggregate colocalizes and binds to the neurofilament light subunit protein that is associated with pathologic neurofilament network disorganization and degeneration of motor neurons. These findings indicate the structure and binding interaction of pro-EMAP II protein and suggest a role of this protein in pathological neurodegenerative diseases. 相似文献
1000.
Jason K. Wasserman Garth Nicholas Rebecca Yaworski Anne-Marie Wasserman John M. Woulfe Gerard H. Jansen Santanu Chakraborty Thanh B. Nguyen 《PloS one》2015,10(4)