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81.
82.
Organic osmolytes are used in animal and plant cells to adapt to hyper- and hypoosmolar stress. We used our RBC-membrane model to investigate the effects of the osmolytes betaine, sorbitol and myo-inositol on Na(+)/K(+)-ATPase, Ca(2+)-ATPase and calmodulin-stimulated Ca(2+)-ATPase (CaM). Our results show that betaine inhibited ATPases by more than 61%: Na(+)/K(+)-ATPase (75 +/- 5.9 vs 27 +/- 2.2), Ca(2+)-ATPase (236 +/- 18.9 vs 62 +/- 4.9), and CaM (450 +/- 18 vs 174 +/- 6.9) (microM pi/min/mg protein, control (0 microM betaine) vs 100 micromol/L betaine). Sorbitol (100 micromol/L) inhibited the Ca(2+)-ATPases by 41% (126 +/- 7.6 vs 74 +/- 4.4) and CaM by 42% (253 +/- 17.7 vs 147 +/- 10.3). Inositol (100 micromol/L) inhibited Na(+)/K(+)-ATPase strongest (37 +/- 1.9 vs 20 +/- 1.0; 47% inhibition) while it showed a lesser effect on the Ca(2+)-ATPases (136 +/- 6.8 vs 102 +/- 5.1; 25% inhibition). All osmolytes inhibited RBC membrane ATPases at concentrations above 50 micromol/L, which corresponds to high normal physiologic range for organic osmolytes in serum. Furthermore, the presence of osmolytes (250 micromol/L) decreased hypoosmotic stress induced hemolysis by 42%. Together these data indicate an important regulatory role of organic osmolytes on human RBC membrane ATPases and a protective function of osmolytes in RBCs against hypoosmotic stress. 相似文献
83.
Natural polysaccharides, derived from biomass feedstocks, marine resources, and microorganisms, have been attracting considerable attention as benign and environmentally friendly substitutes for synthetic polymeric products. Besides many other applications, these biopolymers are rapidly emerging as viable alternatives to harmful synthetic flocculating agents for the removal of contaminants from water and wastewater. In recent years, a great deal of effort has been devoted to improve the production and performance of polysaccharide bio-based flocculants. In this review, current trends in preparation and chemical modification of polysaccharide bio-based flocculants and their flocculation performance are discussed. Aspects including mechanisms of flocculation, biosynthesis, classification, purification and characterization, chemical modification, the effect of physicochemical factors on flocculating activity, and recent applications of polysaccharide bio-based flocculants are summarized and presented. 相似文献
84.
Although the basic plant body plan is established during embryogenesis, the molecular basis of embryonic patterning remains to be fully understood. We have identified two receptor-like kinases, RECEPTOR-LIKE PROTEIN KINASE1 (RPK1) and TOADSTOOL2 (TOAD2), required for Arabidopsis embryonic pattern formation. Genetic analysis indicates that RPK1 and TOAD2 have overlapping embryonic functions. The zygotic gene dosage of TOAD2 in an rpk1 background is of critical importance, suggesting that signaling mediated by RPK1 and TOAD2 must be above a threshold level for proper embryo development. The localization of RPK1 and TOAD2 translational fusions to GFP coupled with the analysis of cell-type-specific markers indicate that RPK1 and TOAD2 are redundantly required for both pattern formation along the radial axis and differentiation of the basal pole during early embryogenesis. We propose that RPK1 and TOAD2 receive intercellular signals and mediate intracellular responses that are necessary for embryonic pattern formation. 相似文献
85.
86.
Functional analysis of Hes-1 in preadipocytes 总被引:3,自引:0,他引:3
87.
M. Elizabeth Sublette Matthew S. Milak Joseph R. Hibbeln Peter J. Freed Maria A. Oquendo Kevin M. Malone Ramin V. Parsey J. John Mann 《Prostaglandins, leukotrienes, and essential fatty acids》2009,80(1):57-64
Deficiencies in polyunsaturated essential fatty acids (PUFA) are implicated in mood disorders, although mechanisms of action and regional specificity in the brain are unknown. We hypothesized that plasma phospholipid PUFA levels are correlated with regionally specific relative cerebral metabolic rates of glucose (rCMRglu). Medication-free depressed subjects (N=29) were studied using [18F]-fluoro-2-deoxyglucose positron emission tomography. Docosahexaenoic acid (22:6n-3), arachidonic acid (20:4n-6), and eicosapentaenoic acid (20:5n-3) were assessed as a percentage of total phospholipid PUFA (DHA%, AA%, and EPA%, respectively). DHA% and AA% correlated positively with rCMRglu in temporoparietal cortex. In addition, DHA% correlated negatively with rCMRglu in prefrontal cortex and anterior cingulate. No correlations were seen with EPA%. Thus, under conditions of low plasma DHA, rCMRglu was higher in temporoparietal cortex and lower in anterior cingulate/prefrontal cortex. Opposing effects of DHA on these regions is a hypothesis that could be addressed in future prospective studies with n-3 supplementation. This pilot study is the first to demonstrate fatty acid and regionally specific correlations in the brain between plasma PUFA and rCMRglu in humans. 相似文献
88.
Zahra B. Mokhtari-Hosseini Ebrahim Vasheghani-Farahani Ali Heidarzadeh-Vazifekhoran S. Abbas Shojaosadati Ramin Karimzadeh Kianoush Khosravi Darani 《Bioresource technology》2009,100(8):2436-2443
Media components were optimized by statistical design for cell growth and PHB production of Methylobacterium extorquens DSMZ 1340. Four important components of growth media were optimized by central composite design. The growth increased from an OD = 1.35 for Choi medium as control to an OD = 2.15 for optimal medium. Then media components for PHB production were optimized. Optimization of five important factors was conducted by response surface method. The optimal composition of PHB production medium was found to be at 7.8 (g/L) Na2HPO4 · 12H2O, and surprisingly at zero concentration of (NH4)2SO4, KH2PO4, MgSO4 and MnSO4. The PHB production was found to be 2.95 (g/L) at this medium. RSM results indicated that a deficiency of nitrogen and magnesium is crucial for PHB accumulation in this microorganism. Also, PHB production was carried out in a 5 L fermentor at the optimum condition which resulted in 9.5 g/L PHB and 15.4 g/L cell dry weight with 62.3% polymer content. 相似文献
89.
Katayoun?JavidniaEmail author Farzaneh?Aram Mahmood?Solouki Ahmad?Reza Mehdiopour Maryam?Gholami Ramin?Miri 《Annals of microbiology》2009,59(2):349
High commercial value compounds can be obtained through the microbial biotransformation of monoterpenes. Some of these monoterpenic substances are not expensive and produced in a variety of plant species. Biotransformation of some monoterpene hydrocarbons such as α-pinene, β-pinene, myrcene and p-cymene by 7 strain bacteria and 2 strain fungi was investigated. It was observed that some of microorganisms transformed monoterpenes to oxygenated monoterpenes in a good yield which among themStaphylococcus epidermidis showed higher yields. 相似文献
90.
Ramin Farzaneh-Far Jue Lin Elissa Epel Kyle Lapham Elizabeth Blackburn Mary A. Whooley 《PloS one》2010,5(1)