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Zielonka J Sarna T Roberts JE Wishart JF Kalyanaraman B 《Archives of biochemistry and biophysics》2006,456(1):39-47
Hydroethidine (HE) is a cell-permeable probe used for the intracellular detection of superoxide. Here, we report the direct measurement of the rate constant between hydroethidine and superoxide radical anion using the pulse radiolysis technique. This reaction rate constant was calculated to be ca. 2 x 10(6) M(-1) s(-1) in water:ethanol (1:1) mixture. The spectral characteristics of the intermediates indicated that the one-electron oxidation product of HE was different from the one-electron reduction product of ethidium (E+). The HPLC-electrochemical measurements of incubation mixtures containing HE and the oxygenated Fenton's reagent (Fe2+/DTPA/H2O2) in the presence of aliphatic alcohols or formate as a superoxide generating system revealed 2-OH-E+ as a major product. Formation of 2-OH-E+ by the Fenton's reagent without additives was shown to be superoxide dismutase-sensitive and we attribute the formation of superoxide radical anion to the one-electron reduction of oxygen by the DTPA-derived radical. Addition of tert-butanol, DMSO, and potassium bromide to the Fenton's system caused inhibition of 2-OH-E+ formation. Results indicate that reducing and oxidizing radicals have differential effects on the formation of 2-OH-E+. 相似文献
205.
Grden M Podgorska M Kocbuch K Szutowicz A Pawelczyk T 《Archives of biochemistry and biophysics》2006,455(1):10-17
Adenosine among other factors is known to regulate the growth and function of cardiac fibroblasts (CFs). Its action is mediated by cell-surface receptors linked to a variety of signaling systems. The goal of present work was to examine the effects of glucose and insulin on adenosine receptors (ARs) mRNA and protein level in primary culture of rat CFs by means of real-time PCR and Western blot. Elevated glucose level increased the expression of A(1)-AR, A(2A)-AR, decreased the expression of A(3)-AR, and had no effect on A(2B)-AR expression. On the other hand insulin suppressed the expression of A(1)-AR, and A(2B)-AR, and had no effect on A(2A)-AR and A(3)-AR expression. Our measurements showed that accumulation of cAMP in response to ARs agonists correlated well with the changes in receptors expression level. These results indicate that changes in glucose and insulin level independently and differentially regulate the ARs expression and functional state in CFs. 相似文献
206.
The reaction of [Ti(cp∗)2(BTMSA)] (1) (cp∗ = η5-C5Me5, BTMSA = bis(trimethylsilyl)acetylene) with malonic acids ((HOOC)2CR2, R = H, Me) and N,N-dimethylglycine resulted in the formation of titanium(IV) dicarboxylato complexes [Ti(cp∗)2{(OOC)2CR2}] (R = H, 2; R = Me, 3) and an α-amino acid titanium(III) complex [Ti(cp∗)2(OOCCH2NMe2)] (4). The identities of complexes 2-4 were confirmed by microanalysis, 1H and 13C NMR spectroscopy (2, 3), ESI-MS and CID experiments (2, 3) as well as by ESR and magnetic measurements (μeff = 1.81, 298 K) for 4. Single X-ray diffraction analyses of 2 and 4 exhibited monomolecular complexes in which the titanium atom is distorted tetrahedrally coordinated by two η5-C5Me5 rings and by the chelating bound malonato-κ2O,O′ (2) and N,N-dimethylglycinato-κ2O,O′ ligand (4). 相似文献
207.
Modulation of a turgor-growth movement called circumnutation in sunflower (Helianthus annuus L.) was investigated using a picture analysis system. Two photoperiod conditions were applied: light–darkness conditions
(LD) 8:8 and LD 20:10. After about 3 weeks of these regimes, the plants were placed under constant light to determine whether
circadian regulation of circumnutation existed or not. The rhythms of movement activity with regard to the trajectory length,
period, and shape of individual circumnutations were examined. Data were processed by Fourier spectral analysis. All the parameters,
trajectory length, period, and shape, revealed the ability to entrain to the administered daily cycles (16 h or 30 h). We
observed diurnal fluctuations of the circumnutation parameters with the phase of the highest trajectory length, the shortest
period, and the highest shape coefficient (the most circular form) during the dark period. After the LD–LL transition, the
parameters revealed periodicity, which was close to 24 h. After several days of a clear circadian free running rhythm, a gradual
decrease of the amplitude of the rhythm was observed. However, the rhythm did not disappear completely. The trajectory length
manifested the strongest entrainment; the circumnutation period and the circumnutation shape were less modulated by photoperiod.
These findings indicate for the first time that different parameters of circumnutation in sunflower are circadian-regulated
rhythms, not solely ultradian as had been thought previously. 相似文献
208.
Tadeusz Wroblewski Katherine S. Caldwell Urszula Piskurewicz Keri A. Cavanaugh Huaqin Xu Alexander Kozik Oswaldo Ochoa Leah K. McHale Kirsten Lahre Joanna Jelenska Jose A. Castillo Daniel Blumenthal Boris A. Vinatzer Jean T. Greenberg Richard W. Michelmore 《Plant physiology》2009,150(4):1733-1749
Bacterial plant pathogens manipulate their hosts by injection of numerous effector proteins into host cells via type III secretion systems. Recognition of these effectors by the host plant leads to the induction of a defense reaction that often culminates in a hypersensitive response manifested as cell death. Genes encoding effector proteins can be exchanged between different strains of bacteria via horizontal transfer, and often individual strains are capable of infecting multiple hosts. Host plant species express diverse repertoires of resistance proteins that mediate direct or indirect recognition of bacterial effectors. As a result, plants and their bacterial pathogens should be considered as two extensive coevolving groups rather than as individual host species coevolving with single pathovars. To dissect the complexity of this coevolution, we cloned 171 effector-encoding genes from several pathovars of Pseudomonas and Ralstonia. We used Agrobacterium tumefaciens-mediated transient assays to test the ability of each effector to induce a necrotic phenotype on 59 plant genotypes belonging to four plant families, including numerous diverse accessions of lettuce (Lactuca sativa) and tomato (Solanum lycopersicum). Known defense-inducing effectors (avirulence factors) and their homologs commonly induced extensive necrosis in many different plant species. Nonhost species reacted to multiple effector proteins from an individual pathovar more frequently and more intensely than host species. Both homologous and sequence-unrelated effectors could elicit necrosis in a similar spectrum of plants, suggesting common effector targets or targeting of the same pathways in the plant cell. 相似文献
209.
Agnieszka Bajda Dorota Konopka-Postupolska Magdalena Krzymowska Jacek Hennig Karolina Skorupinska-Tudek Liliana Surmacz Jacek Wójcik Zdzislaw Matysiak Tadeusz Chojnacki Ewa Skorzynska-Polit Maria Drazkiewicz Pawel Patrzylas Monika Tomaszewska Magdalena Kania Malgorzata Swist Witold Danikiewicz Wieslawa Piotrowska and Ewa Swiezewska 《Physiologia plantarum》2009,135(4):351-364
Infection with avirulent pathogens, tobacco mosaic virus (TMV) or Pseudomonas syringae pv. tabaci induced accumulation of polyisoprenoid alcohols, solanesol and a family of polyprenols [from polyprenol composed of 14 isoprene units (Pren-14) to -18, with Pren-16 dominating] in the leaves of resistant tobacco plants Nicotiana tabacum cv. Samsun NN. Upon TMV infection, solanesol content was increased seven- and eight-fold in the inoculated and upper leaves, respectively, while polyprenol content was increased 2.5- and 2-fold in the inoculated and upper leaves, respectively, on the seventh day post-infection. Accumulation of polyisoprenoid alcohols was also stimulated by exogenously applied hydrogen peroxide but not by exogenous salicylic acid (SA). On the contrary, neither inoculation of the leaves of susceptible tobacco plants nor wounding of tobacco leaves caused an increase in polyisoprenoid content. Taken together, these results indicate that polyisoprenoid alcohols might be involved in plant resistance against pathogens. A putative role of accumulated polyisoprenoids in plant response to pathogen attack is discussed. Similarly, the content of plastoquinone (PQ) was increased two-fold in TMV-inoculated and upper leaves of resistant plants. Accumulation of PQ was also stimulated by hydrogen peroxide, bacteria ( P. syringae ) and SA. The role of PQ in antioxidant defense in cellular membranous compartments is discussed in the context of the enzymatic antioxidant machinery activated in tobacco leaves subjected to viral infection. Elevated activity of several antioxidant enzymes (ascorbate peroxidase, guaiacol peroxidase, glutathione reductase and superoxide dismutase, especially the CuZn superoxide dismutase isoform) and high, but transient elevation of catalase was found in inoculated leaves of resistant tobacco plants but not in susceptible plants. 相似文献
210.
The Sunshine Farm, in central Kansas, offers a unique data set detailing all the inputs and outputs of a farming project intended to be based, as much as possible, on solar energy. Such a complete and detailed data set, encompassing more than 1.25 M data points for an 85-ha, 7-year project, has never before been compiled for any farm. The data show that important energy inputs that have thus far been left out of existing farm energy efficiency estimates, with implications for biofuels and other biomass for energy technologies. The SSF achieved energy efficiencies superior to conventional agriculture while maintaining soil health and delivering more nutritious, organic products. A first-ever analysis of the energy efficiency of horse traction shows that horses are significantly less energy efficient and much less labor efficient than tractors, although the horses in the study were clearly underutilized. An analysis of the farm removing all inputs and outputs relevant to the horses shows that without horses the Sunshine Farm would have been competitive with conventional energy efficiencies even taking into account the farm's higher labor inputs and small size. 相似文献