Статті в журналах: "Redox-type Mechanism"

1

Lewenstam, Andrzej, Johan Bobacka, and Ari Ivaska. "Mechanism of ionic and redox sensitivity of p-type conducting polymers." Journal of Electroanalytical Chemistry 368, no. 1-2 (April 1994): 23–31. http://dx.doi.org/10.1016/0022-0728(93)03080-9.

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2

Bobacka, Johan, Zhiqiang Gao, Ari Ivaska, and Andrzej Lewenstam. "Mechanism of ionic and redox sensitivity of p-type conducting polymers." Journal of Electroanalytical Chemistry 368, no. 1-2 (April 1994): 33–41. http://dx.doi.org/10.1016/0022-0728(93)03081-y.

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3

Liu, Guijie, Xing Liu, Hongjiao Xu, Xichun Liu, Hu Zhou, Zhen Huang, Jianhua Gan, Hao Chen, Lefu Lan, and Cai-Guang Yang. "Structural Insights into the Redox-Sensing Mechanism of MarR-Type Regulator AbfR." Journal of the American Chemical Society 139, no. 4 (January 23, 2017): 1598–608. http://dx.doi.org/10.1021/jacs.6b11438.

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4

Feuge, Niklas, Jan C. Namyslo, Dieter E. Kaufmann, and René Wilhelm. "Intramolecular Phosphine-Promoted Knoevenagel Based Redox-Reaction." Molecules 27, no. 15 (July 29, 2022): 4875. http://dx.doi.org/10.3390/molecules27154875.

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A Knoevenagel based redox-reaction promoted by intramolecular phosphine sources is presented for the first time. The influence of different diketones, aldehydes, bases and acids was investigated. The effects of different substituents were evaluated based on their electronical influence on the diketone structure. With the obtained results a mechanism is proposed, giving information about transition states formed during the reaction, which can lead to different products. This type of an internal redox transformation with a phosphine oxide moiety remaining in the molecule after the redox reaction represents a new type of reaction.

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5

Cheng, Chen, Manling Ding, Tianran Yan, Kehua Dai, Jing Mao, Nian Zhang, Liang Zhang, and Jinghua Guo. "Exploring the Charge Compensation Mechanism of P2-Type Na0.6Mg0.3Mn0.7O2 Cathode Materials for Advanced Sodium-Ion Batteries." Energies 13, no. 21 (November 2, 2020): 5729. http://dx.doi.org/10.3390/en13215729.

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P2-type sodium layered transition metal oxides have been intensively investigated as promising cathode materials for sodium-ion batteries (SIBs) by virtue of their high specific capacity and high operating voltage. However, they suffer from problems of voltage decay, capacity fading, and structural deterioration, which hinder their practical application. Therefore, a mechanistic understanding of the cationic/anionic redox activity and capacity fading is indispensable for the further improvement of electrochemical performance. Here, a prototype cathode material of P2-type Na0.6Mg0.3Mn0.7O2 is comprehensively investigated, which presents both cationic and anionic redox behaviors during the cycling process. By a combination of soft X-ray absorption spectroscopy and electroanalytical methods, we unambiguously reveal that only oxygen redox reaction is involved in the initial charge process, then both oxygen and manganese participate in the charge compensation in the following discharge process. In addition, a gradient distribution of Mn valence state from surface to bulk is disclosed, which could be mainly related to the irreversible oxygen activity during the charge process. Furthermore, we find that the average oxidation state of Mn is reduced upon extended cycles, leading to the noticeable capacity fading. Our results provide deeper insights into the intrinsic cationic/anionic redox mechanism of P2-type materials, which is vital for the rational design and optimization of advanced cathode materials for SIBs.

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6

Qin, Shuhao, Lei Dong, Zhuqi Chen, Sicheng Zhang, and Guochuan Yin. "Non-redox metal ions can promote Wacker-type oxidations even better than copper(ii): a new opportunity in catalyst design." Dalton Transactions 44, no. 40 (2015): 17508–15. http://dx.doi.org/10.1039/c5dt02612a.

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7

Puchades, Ivan, Colleen C. Lawlor, Christopher M. Schauerman, Andrew R. Bucossi, Jamie E. Rossi, Nathanael D. Cox, and Brian J. Landi. "Mechanism of chemical doping in electronic-type-separated single wall carbon nanotubes towards high electrical conductivity." Journal of Materials Chemistry C 3, no. 39 (2015): 10256–66. http://dx.doi.org/10.1039/c5tc02053k.

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8

Aizhulov, D. Y., N. M. Shayakhmetov, and A. Kaltayev. "Quantitative Model of the Formation Mechanism of the Rollfront Uranium Deposits." Eurasian Chemico-Technological Journal 20, no. 3 (September 28, 2018): 213. http://dx.doi.org/10.18321/ectj724.

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The rollfront type deposits are crescent shaped accumulation of mineralization including uranium, selenium, molybdenum in reduced permeable sandstones. It generally forms within a geochemical barrier between mostly reduced and predominantly oxidized environments. Redox reactions between oxidant and reductant creates favorable conditions for uranium precipitation, while constant flow of oxidant continuously dissolves uranium minerals thereby creating a reactive transport. Several previous works had either focused on the characteristics of the rollfront type deposits, or on the description of chemical and geological processes involved in their genesis. Based on these previous works, authors aimed to mimic laboratory experiments numerically by reactive flow and numerical simulation. Data from one particular experiment was used to determine reaction rates between reactants to produce a model of reactive transport and chemical processes involved in the formation of rollfront type deposits. The resulting model was used to identify the causes of crescent like formations and to determine main mechanisms influencing rollfront evolution. A better understanding and simulation of the mechanism involved in the formation of rollfront type deposits and their properties would contribute to decreased exploration and production costs of commodities trapped within such accumulations. The results of this work can be used to model other deposits formed through infiltration and subsequent precipitation of various minerals at the redox interface.

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9

Ježek, Petr, Andrea Dlasková, and Lydie Plecitá-Hlavatá. "Redox Homeostasis in Pancreatic Cells." Oxidative Medicine and Cellular Longevity 2012 (2012): 1–16. http://dx.doi.org/10.1155/2012/932838.

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We reviewed mechanisms that determine reactive oxygen species (redox) homeostasis, redox information signaling and metabolic/regulatory function of autocrine insulin signaling in pancreaticβcells, and consequences of oxidative stress and dysregulation of redox/information signaling for their dysfunction. We emphasize the role of mitochondrion inβcell molecular physiology and pathology, including the antioxidant role of mitochondrial uncoupling protein UCP2. Since in pancreaticβcells pyruvate cannot be easily diverted towards lactate dehydrogenase for lactate formation, the respiration and oxidative phosphorylation intensity are governed by the availability of glucose, leading to a certain ATP/ADP ratio, whereas in other cell types, cell demand dictates respiration/metabolism rates. Moreover, we examine the possibility that type 2 diabetes mellitus might be considered as an inevitable result of progressive self-accelerating oxidative stress and concomitantly dysregulated information signaling in peripheral tissues as well as in pancreaticβcells. It is because the redox signaling is inherent to the insulin receptor signaling mechanism and its impairment leads to the oxidative and nitrosative stress. Also emerging concepts, admiting participation of redox signaling even in glucose sensing and insulin release in pancreaticβcells, fit in this view. For example, NADPH has been firmly established to be a modulator of glucose-stimulated insulin release.

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10

Lee, Jeonghan, Michael T. Nelson, Kirstin E. Rose, and Slobodan M. Todorovic. "Redox Mechanism of S-Nitrosothiol Modulation of Neuronal CaV3.2 T-Type Calcium Channels." Molecular Neurobiology 48, no. 2 (June 28, 2013): 274–80. http://dx.doi.org/10.1007/s12035-013-8493-8.

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11

Seidel, Thorsten, Stefan Scholl, Melanie Krebs, Florian Rienmüller, Irene Marten, Rainer Hedrich, Miriam Hanitzsch, Patricia Janetzki, Karl-Josef Dietz, and Karin Schumacher. "Regulation of the V-type ATPase by redox modulation." Biochemical Journal 448, no. 2 (November 7, 2012): 243–51. http://dx.doi.org/10.1042/bj20120976.

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ATP-hydrolysis and proton pumping by the V-ATPase (vacuolar proton-translocating ATPase) are subject to redox regulation in mammals, yeast and plants. Oxidative inhibition of the V-ATPase is ascribed to disulfide-bond formation between conserved cysteine residues at the catalytic site of subunit A. Subunits containing amino acid substitutions of one of three conserved cysteine residues of VHA-A were expressed in a vha-A null mutant background in Arabidopsis. In vitro activity measurements revealed a complete absence of oxidative inhibition in the transgenic line expressing VHA-A C256S, confirming that Cys256 is necessary for redox regulation. In contrast, oxidative inhibition was unaffected in plants expressing VHA-A C279S and VHA-A C535S, indicating that disulfide bridges involving these cysteine residues are not essential for oxidative inhibition. In vivo data suggest that oxidative inhibition might not represent a general regulatory mechanism in plants.

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12

Sirisinudomkit, Pichamon, Pawin Iamprasertkun, Atiweena Krittayavathananon, Tanut Pettong, Peerapan Dittanet, Pinit Kidkhunthod, and Montree Sawangphruk. "Hybrid energy storage of battery-type nickel hydroxide and supercapacitor-type graphene: redox additive and charge storage mechanism." Sustainable Energy & Fuels 1, no. 2 (2017): 275–79. http://dx.doi.org/10.1039/c7se00052a.

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13

Arena, Francesco, Roberto di Chio, Claudia Espro, Alessandra Palella, and Lorenzo Spadaro. "A definitive assessment of the CO oxidation pattern of a nanocomposite MnCeOx catalyst." Reaction Chemistry & Engineering 3, no. 3 (2018): 293–300. http://dx.doi.org/10.1039/c8re00026c.

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14

Palm, Gottfried J., Bui Khanh Chi, Paul Waack, Katrin Gronau, Dörte Becher, Dirk Albrecht, Winfried Hinrichs, Randy J. Read, and Haike Antelmann. "Structural insights into the redox-switch mechanism of the MarR/DUF24-type regulator HypR." Nucleic Acids Research 40, no. 9 (January 11, 2012): 4178–92. http://dx.doi.org/10.1093/nar/gkr1316.

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15

Romańczyk, Piotr P., Grzegorz Rotko, and Stefan S. Kurek. "Dissociative electron transfer in polychlorinated aromatics. Reduction potentials from convolution analysis and quantum chemical calculations." Physical Chemistry Chemical Physics 18, no. 32 (2016): 22573–82. http://dx.doi.org/10.1039/c6cp02222g.

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The combination of convolution analysis and quantum-chemical calculations at DFT and CCSD(T)-F12 levels allows the determination of standard redox potentials and the mechanism type of dissociative ET in environmentally relevant polychlorinated benzenes.

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16

Campbell, D. L., J. S. Stamler, and H. C. Strauss. "Redox modulation of L-type calcium channels in ferret ventricular myocytes. Dual mechanism regulation by nitric oxide and S-nitrosothiols." Journal of General Physiology 108, no. 4 (October 1, 1996): 277–93. http://dx.doi.org/10.1085/jgp.108.4.277.

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The effects of NO-related activity and cellular thiol redox state on basal L-type calcium current, ICa,L, in ferret right ventricular myocytes were studied using the patch clamp technique. SIN-1, which generates both NO. and O2-, either inhibited or stimulated ICa,L. In the presence of superoxide dismutase only inhibition was seen. 8-Br-cGMP also inhibited ICa,L, suggesting that the NO inhibition is cGMP-dependent. On the other hand, S-nitrosothiols (RSNOs), which donate NO+, stimulated ICa,L. RSNO effects were not dependent upon cell permeability, modulation of SR Ca2+ release, activation of kinases, inhibition of phosphatases, or alterations in cGMP levels. Similar activation of ICa,L by thiol oxidants, and reversal by thiol reductants, identifies an allosteric thiol-containing "redox switch" on the L-type calcium channel subunit complex by which NO/O2- and NO+ transfer can exert effects opposite to those produced by NO. In sum, our results suggest that: (a) both indirect (cGMP-dependent) and direct (S-nitrosylation/oxidation) regulation of ventricular ICa,L, and (b) sarcolemma thiol redox state may be an important determinant of ICa,L activity.

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17

Ajduković, Marija, Nataša Jović-Jovičić, Aleksandra Milutinović-Nikolić, Predrag Banković, and Zorica Mojović. "The influence of clay modification on electrochemical behavior of quinhydrone." Tehnika 77, no. 1 (2022): 9–14. http://dx.doi.org/10.5937/tehnika2201009a.

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Montmorillonite originated from Wyoming was modified by acid activation and aluminum pillaring process. The samples of clay obtained in this manner, as well as starting clay, were applied at the surface of a glassy carbon electrode by the means of Nafion. The activity of these electrodes was investigated on the redox couple quinone/hydroquinone (Q/QH2) in buffered and unbuffered solutions. The type of clay modification influenced the activity of the electrodes and the mechanism of the redox reaction.

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18

Si, Meiru, Can Chen, Chengchuan Che, Yang Liu, Xiaona Li, and Tao Su. "The thiol oxidation-based sensing and regulation mechanism for the OasR-mediated organic peroxide and antibiotic resistance in C. glutamicum." Biochemical Journal 477, no. 19 (October 5, 2020): 3709–27. http://dx.doi.org/10.1042/bcj20200533.

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Corynebacterium glutamicum, an important industrial and model microorganism, inevitably encountered stress environment during fermentative process. Therefore, the ability of C. glutamicum to withstand stress and maintain the cellular redox balance was vital for cell survival and enhancing fermentation efficiency. To robustly survive, C. glutamicum has been equipped with many types of redox sensors. Although cysteine oxidation-based peroxide-sensing regulators have been well described in C. glutamicum, redox sensors involving in multiple environmental stress response remained elusive. Here, we reported an organic peroxide- and antibiotic-sensing MarR (multiple antibiotics resistance regulators)-type regulator, called OasR (organic peroxide- and antibiotic-sensing regulator). The OasR regulator used Cys95 oxidation to sense oxidative stress to form S-mycothiolated monomer or inter-molecular disulfide-containing dimer, resulting in its dissociation from the target DNA promoter. Transcriptomics uncovered the strong up-regulation of many multidrug efflux pump genes and organic peroxide stress-involving genes in oasR mutant, consistent with the phenomenon that oasR mutant showed a reduction in sensitivity to antibiotic and organic peroxide. Importantly, the addition of stress-associated ligands such as cumene hydroperoxide and streptomycin induced oasR and multidrug efflux pump protein NCgl1020 expression in vivo. We speculated that cell resistance to antibiotics and organic peroxide correlated with stress response-induced up-regulation of genes expression. Together, the results revealed that OasR was a key MarR-type redox stress-responsive transcriptional repressor, and sensed oxidative stress generated through hydroxyl radical formation to mediate antibiotic resistance in C. glutamicum.

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19

Chen, Chwen-Lih, Liwen Zhang, Zhicheng Jin, Takhar Kasumov, and Yeong-Renn Chen. "Mitochondrial redox regulation and myocardial ischemia-reperfusion injury." American Journal of Physiology-Cell Physiology 322, no. 1 (January 1, 2022): C12—C23. http://dx.doi.org/10.1152/ajpcell.00131.2021.

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Mitochondrial reactive oxygen species (ROS) have emerged as an important mechanism of disease and redox signaling in the cellular system. Under basal or pathological conditions, electron leakage for ROS production is primarily mediated by complexes I and III of the electron transport chain (ETC) and by the proton motive force (PMF), consisting of a membrane potential (ΔΨ) and a proton gradient (ΔpH). Several factors control redox status in mitochondria, including ROS, the PMF, oxidative posttranslational modifications (OPTM) of the ETC subunits, SOD2, and cytochrome c heme lyase (HCCS). In the mitochondrial PMF, increased ΔpH-supported backpressure due to diminishing electron transport and chemiosmosis promotes a more reductive mitochondrial physiological setting. OPTM by protein cysteine sulfonation in complex I and complex III has been shown to affect enzymatic catalysis, the proton gradient, redox status, and enzyme-mediated ROS production. Pathological conditions associated with oxidative or nitrosative stress, such as myocardial ischemia and reperfusion (I/R), increase mitochondrial ROS production and redox dysfunction via oxidative injury to complexes I and III, intensely enhancing protein cysteine sulfonation and impairing heme integrity. The physiological conditions of reductive stress induced by gains in SOD2 function normalize I/R-mediated ROS overproduction and redox dysfunction. Further insight into the cellular mechanisms by which HCCS, biogenesis of c-type cytochrome, and OPTM regulate PMF and ROS production in mitochondria will enrich our understanding of redox signal transduction and identify new therapeutic targets for cardiovascular diseases in which oxidative stress perturbs normal redox signaling.

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20

Appiah, Isabella, Aleksandra Nikolic-Kokic, Zorana Orescanin-Dusic, Ratko Radojicic, Slobodan Milovanovic, Mihajlo Spasic, and Dusko Blagojevic. "Reversible Oxidation of Myometrial Voltage-Gated Potassium Channels with Hydrogen Peroxide." Oxidative Medicine and Cellular Longevity 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/105820.

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The uteri, spontaneously active or Ca2+(6 mM) induced, were allowed to equilibrate, and to inhibit voltage-gated potassium (KV) channels 1 mM 4-amino pyridine (4-AP) was applied for 15 min before adding H2O2 . H2O2was added cumulatively: 2 μM, 20 μM, 200 μM, 400 μM, and 3 mM. Average time for H2O2concentrations (2, 20, 200, and 400)μM to reach its full effect was 15 min. H2O23 mM had a prolonged effect and therefore was left to act for 30 min. Two-way ANOVA showed significant differences in time dependency between spontaneous and Ca2+-induced rat uteri after applying 3 mM H2O2(type of contraction,P=0.0280), but not 400 μM H2O2(P=0.9271). Our results indicate that H2O2oxidises channel intracellular thiol groups and activates the channel, inducing relaxation. Cell antioxidative defence system quickly activates glutathione peroxidase (GSHPx) defence mechanism but not catalase (CAT) defence mechanism. Intracellular redox mechanisms repair the oxidised sites and again establish deactivation ofKVchannels, recuperating contractility. In conclusion, our results demonstrate thatKVchannels can be altered in a time-dependent manner by reversible redox-dependent intracellular alterations.

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21

Ooi, Kenta, Yoshitaka Miyai, and Jitsuo Sakakihara. "Mechanism of lithium(1+) insertion in spinel-type manganese oxide. Redox and ion-exchange reactions." Langmuir 7, no. 6 (June 1991): 1167–71. http://dx.doi.org/10.1021/la00054a025.

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22

Kim, Myungkyu, Hyungjun Kim, Maenghyo Cho, and Duho Kim. "Unlocking veiled oxygen redox in Na-based earth-abundant binary layered oxide." Journal of Materials Chemistry A 9, no. 27 (2021): 15179–87. http://dx.doi.org/10.1039/d1ta02789a.

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The charge compensation mechanism of P2-type binary Na_2/3−x[Mn_1/2Fe_1/2]O₂ oxide is reinvestigated to unlock veiled oxygen redox reactions upon charging and their activities are selectively determined by transition metal configurations.

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23

Suzuki, Takashi, Akari Sato, Hiromi Oshita, Tatsuo Yajima, Fumito Tani, Hitoshi Abe, Kaoru Mieda-Higa, Sachiko Yanagisawa, Takashi Ogura, and Yuichi Shimazaki. "Formation of Ni(ii)-phenoxyl radical complexes by O2: a mechanistic insight into the reaction of Ni(ii)-phenol complexes with O2." Dalton Transactions 50, no. 15 (2021): 5161–70. http://dx.doi.org/10.1039/d1dt00105a.

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The reaction of Ni(ii)-(phenol)(phenolate) complexes with O₂ gave the Ni(ii)-phenoxyl radical complexes assisted by CH₃OH. This reaction was concluded to undergo via the proton transfer–electron transfer type mechanism without redox of the Ni ion.

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24

Alexandre, Gladys, Suzanne E. Greer, and Igor B. Zhulin. "Energy Taxis Is the Dominant Behavior in Azospirillum brasilense." Journal of Bacteriology 182, no. 21 (November 1, 2000): 6042–48. http://dx.doi.org/10.1128/jb.182.21.6042-6048.2000.

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ABSTRACT Energy taxis encompasses aerotaxis, phototaxis, redox taxis, taxis to alternative electron acceptors, and chemotaxis to oxidizable substrates. The signal for this type of behavior is originated within the electron transport system. Energy taxis was demonstrated, as a part of an overall behavior, in several microbial species, but it did not appear as the dominant determinant in any of them. In this study, we show that most behavioral responses proceed through this mechanism in the alpha-proteobacterium Azospirillum brasilense. First, chemotaxis to most chemoeffectors typical of the azospirilla habitat was found to be metabolism dependent and required a functional electron transport system. Second, other energy-related responses, such as aerotaxis, redox taxis, and taxis to alternative electron acceptors, were found in A. brasilense. Finally, a mutant lacking a cytochromec oxidase of the cbb 3 type was affected in chemotaxis, redox taxis, and aerotaxis. Altogether, the results indicate that behavioral responses to most stimuli inA. brasilense are triggered by changes in the electron transport system.

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25

Joshi, Shweta Kanungo, Neena Sohani, Savita Khare, and Rajendra Prasad. "Kinetics and Mechanism of Slurry Phase Air Oxidation of Benzyl Alcohol over Zirconium Vanadate Catalyst." Asian Journal of Chemistry 33, no. 1 (2020): 108–12. http://dx.doi.org/10.14233/ajchem.2021.22947.

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The kinetics of slurry phase air oxidation of benzyl alcohol to benzaldehyde over zirconium vanadate catalyst is reported in this study. Initial rates for the formation of product were determined by varying the partial pressures of the reactants. The data collected were found to satisfy a rate law: R = [(k1PBk2Po)/(k1PB + k2Po)]. The study suggests that reaction follows a Mars-Van Krevelen type of redox mechanism.

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26

Costentin, Cyrille, and Jean-Michel Savéant. "Concepts and tools for mechanism and selectivity analysis in synthetic organic electrochemistry." Proceedings of the National Academy of Sciences 116, no. 23 (May 17, 2019): 11147–52. http://dx.doi.org/10.1073/pnas.1904439116.

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As an accompaniment to the current renaissance of synthetic organic electrochemistry, the heterogeneous and space-dependent nature of electrochemical reactions is analyzed in detail. The reactions that follow the initial electron transfer step and yield the products are intimately coupled with reactant transport. Depiction of the ensuing reactions profiles is the key to the mechanism and selectivity parameters. Analysis is eased by the steady state resulting from coupling of diffusion with convection forced by solution stirring or circulation. Homogeneous molecular catalysis of organic electrochemical reactions of the redox or chemical type may be treated in the same manner. The same benchmarking procedures recently developed for the activation of small molecules in the context of modern energy challenges lead to the establishment and comparison of the catalytic Tafel plots. At the very opposite, redox-neutral chemical reactions may be catalyzed by injection (or removal) of an electron from the electrode. This class of reactions has currently few, but very thoroughly analyzed, examples. It is likely that new cases will emerge in the near future.

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27

Xu, Feng, Juozas J. Kulys, Kyle Duke, Kaichang Li, Kastis Krikstopaitis, Heinz-Josef W. Deussen, Eric Abbate, Vilija Galinyte, and Palle Schneider. "Redox Chemistry in Laccase-Catalyzed Oxidation of N-Hydroxy Compounds." Applied and Environmental Microbiology 66, no. 5 (May 1, 2000): 2052–56. http://dx.doi.org/10.1128/aem.66.5.2052-2056.2000.

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ABSTRACT 1-Hydroxybenzotriazole, violuric acid, andN-hydroxyacetanilide are three N-OH compounds capable of mediating a range of laccase-catalyzed biotransformations, such as paper pulp delignification and degradation of polycyclic hydrocarbons. The mechanism of their enzymatic oxidation was studied with seven fungal laccases. The oxidation had a bell-shaped pH-activity profile with an optimal pH ranging from 4 to 7. The oxidation rate was found to be dependent on the redox potential difference between the N-OH substrate and laccase. A laccase with a higher redox potential or an N-OH compound with a lower redox potential tended to have a higher oxidation rate. Similar to the enzymatic oxidation of phenols, phenoxazines, phenothiazines, and other redox-active compounds, an “outer-sphere” type of single-electron transfer from the substrate to laccase and proton release are speculated to be involved in the rate-limiting step for N-OH oxidation.

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28

SENDA, Miki, Shigenobu KIMURA, Masao FUKUDA, Tetsuo ISHIDA, and Toshiya SENDA. "Molecular Mechanism of the Redox-dependent Interaction between NADH-dependent Ferredoxin Reductase and Rieske-type Ferredoxin." Nihon Kessho Gakkaishi 50, no. 6 (2008): 341–47. http://dx.doi.org/10.5940/jcrsj.50.341.

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29

Yan, Liang-Jun. "The Nicotinamide/Streptozotocin Rodent Model of Type 2 Diabetes: Renal Pathophysiology and Redox Imbalance Features." Biomolecules 12, no. 9 (September 2, 2022): 1225. http://dx.doi.org/10.3390/biom12091225.

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Diabetic nephropathy (DN) is a common complication of diabetes mellitus. While there has been a great advance in our understanding of the pathogenesis of DN, no effective managements of this chronic kidney disease are currently available. Therefore, continuing to elucidate the underlying biochemical and molecular mechanisms of DN remains a constant need. In this regard, animal models of diabetes are indispensable tools. This review article highlights a widely used rodent model of non-obese type 2 diabetes induced by nicotinamide (NA) and streptozotocin (STZ). The mechanism underlying diabetes induction by combining the two chemicals involves blunting the toxic effect of STZ by NA so that only a percentage of β cells are destroyed and the remaining viable β cells can still respond to glucose stimulation. This NA-STZ animal model, as a platform for the testing of numerous antidiabetic and renoprotective materials, is also discussed. In comparison with other type 2 diabetic animal models, such as high-fat-diet/STZ models and genetically engineered rodent models, the NA-STZ model is non-obese and is less time-consuming and less expensive to create. Given that this unique model mimics certain pathological features of human DN, this model should continue to find its applications in the field of diabetes research.

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30

Higgins, Jacob S., Lawson T. Lloyd, Sara H. Sohail, Marco A. Allodi, John P. Otto, Rafael G. Saer, Ryan E. Wood, et al. "Photosynthesis tunes quantum-mechanical mixing of electronic and vibrational states to steer exciton energy transfer." Proceedings of the National Academy of Sciences 118, no. 11 (March 9, 2021): e2018240118. http://dx.doi.org/10.1073/pnas.2018240118.

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Анотація:

Photosynthetic species evolved to protect their light-harvesting apparatus from photoxidative damage driven by intracellular redox conditions or environmental conditions. The Fenna–Matthews–Olson (FMO) pigment–protein complex from green sulfur bacteria exhibits redox-dependent quenching behavior partially due to two internal cysteine residues. Here, we show evidence that a photosynthetic complex exploits the quantum mechanics of vibronic mixing to activate an oxidative photoprotective mechanism. We use two-dimensional electronic spectroscopy (2DES) to capture energy transfer dynamics in wild-type and cysteine-deficient FMO mutant proteins under both reducing and oxidizing conditions. Under reducing conditions, we find equal energy transfer through the exciton 4–1 and 4–2-1 pathways because the exciton 4–1 energy gap is vibronically coupled with a bacteriochlorophyll-a vibrational mode. Under oxidizing conditions, however, the resonance of the exciton 4–1 energy gap is detuned from the vibrational mode, causing excitons to preferentially steer through the indirect 4–2-1 pathway to increase the likelihood of exciton quenching. We use a Redfield model to show that the complex achieves this effect by tuning the site III energy via the redox state of its internal cysteine residues. This result shows how pigment–protein complexes exploit the quantum mechanics of vibronic coupling to steer energy transfer.

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Kang, Jin-Wei, and Han-Yi Chen. "Cation-Modified Anionic Redox Mechanism for High-Performance Layered Oxide As Sodium-Ion Batteries Cathode Material." ECS Meeting Abstracts MA2022-01, no. 3 (July 7, 2022): 490. http://dx.doi.org/10.1149/ma2022-013490mtgabs.

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Sodium-ion batteries (NIBs) have been selected as a promising candidate for large-scale energy storage systems due to their abundance. Among several NIB cathode materials, P2-type transition metal layered oxides (NaxTMO2, TM = Ti, V, Cr, Mn, Fe, Co, Ni) featuring high theoretical capacity and better rate performance have attracted much attention. However, the practical applications have to endure the low energy density of NIB cathode materials compared to lithium-ion batteries. In tradition, the capacity is constrained by transition metal ions and is closed to their limits. Hence,in order to obtain extraordinarily high capacity in cathode materials, both anionic and cationic redox chemistry are utilized. Nevertheless, their performance is impeded by irreversible structure evolution and lattice oxygen emission. Therefore, it is highly urgent to develop stable anionic redox chemistry for high energy density and long-cycle-life layered oxide cathode materials. In this study, cation-doped NaxMgyCuzMn(1−y−z)O2 cathode material featuring synergistic effects of cationic and anionic redox was reported. By cations doping, the inhibited structure evolution and lattice oxygen stabilization were achieved. Moreover, the effects of cation-doped NaxMgyCuzMn(1−y−z)O2 were also studied by electrochemical measurements. Also, the mechanism of cation-doped NaxMgyCuzMn(1−y−z)O2 was confirmed by operando synchrotron X-ray absorption spectrum, operando X-ray diffraction, and density functional theory computations. Cation-doped NaxMgyCuzMn(1−y−z)O2 was synthesized through a facile sol-gel method followed by heat treatment. The cation-doped NaxMgyCuzMn(1−y−z)O2 showed high specific capacity (203 mAh g− 1 cycled at 0.1C) as well as better cycling stability, providing sodium layered oxides a new developing stage toward high-performance cathode materials in NIBs for large scale energy storage systems. Keywords: Na-ion batteries, layered oxides, anionic redox, cathode

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32

O'Malley, Yunxia Q., Maher Y. Abdalla, Michael L. McCormick, Krzysztof J. Reszka, Gerene M. Denning, and Bradley E. Britigan. "Subcellular localization ofPseudomonaspyocyanin cytotoxicity in human lung epithelial cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 284, no. 2 (February 1, 2003): L420—L430. http://dx.doi.org/10.1152/ajplung.00316.2002.

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The Pseudomonas aeruginosa secretory product pyocyanin damages lung epithelium, likely due to redox cycling of pyocyanin and resultant superoxide and H2O2generation. Subcellular site(s) of pyocyanin redox cycling and toxicity have not been well studied. Therefore, pyocyanin's effects on subcellular parameters in the A549 human type II alveolar epithelial cell line were examined. Confocal and electron microscopy studies suggested mitochondrial redox cycling of pyocyanin and extracellular H2O2release, respectively. Pyocyanin decreased mitochondrial and cytoplasmic aconitase activity, ATP levels, cellular reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, and mitochondrial membrane potential. These effects were transient at low pyocyanin concentrations and were linked to apparent cell-mediated metabolism of pyocyanin. Overexpression of MnSOD, but not CuZnSOD or catalase, protected cellular aconitase, but not ATP, from pyocyanin-mediated depletion. This suggests that loss of aconitase activity is not responsible for ATP depletion. How pyocyanin leads to ATP depletion, the mechanism of cellular metabolism of pyocyanin, and the impact of mitochondrial pyocyanin redox cycling on other cellular events are important areas for future study.

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33

Kim, Eun Jeong, Le Anh Ma, Laurent C. Duda, David M. Pickup, Alan V. Chadwick, Reza Younesi, John T. S. Irvine, and A. Robert Armstrong. "Oxygen Redox Activity through a Reductive Coupling Mechanism in the P3-Type Nickel-Doped Sodium Manganese Oxide." ACS Applied Energy Materials 3, no. 1 (December 26, 2019): 184–91. http://dx.doi.org/10.1021/acsaem.9b02171.

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34

Imhoff, Barry R., and Jason M. Hansen. "Extracellular redox status regulates Nrf2 activation through mitochondrial reactive oxygen species." Biochemical Journal 424, no. 3 (December 10, 2009): 491–500. http://dx.doi.org/10.1042/bj20091286.

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The redox status of the extracellular compartment has only just been elucidated as a mechanism controlling intracellular signal transduction and correlates with aging, diabetes, heart disease and lung fibrosis. In the present paper, we describe a mechanism by which oxidizing extracellular environments, as maintained by the cysteine/cystine (Cys/CySS) redox couple, induce mitochondria-derived ROS (reactive oxygen species) generation and cause the activation of Nrf2 (nuclear factor-erythroid 2-related factor 2), inducing an antioxidant response. NIH 3T3 cells were cultured in medium with extracellular Cys/CySS redox potentials (Eh), ranging from 0 to −150 mV. Cellular and mitochondrial ROS production significantly increased in cells incubated under more oxidizing extracellular conditions (0 and −46 mV). Trx2 (thioredoxin-2) is a mitochondrial-specific oxidoreductase and antioxidant and became oxidized in cells incubated at 0 or −46 mV. MEFs (mouse embryonic fibroblasts) from Trx2-overexpressing transgenic (Trx2 Tg) mice produced less intracellular ROS compared with WT (wild-type) MEFs at the more oxidizing extracellular conditions. Nrf2 activity was increased in WT MEFs at the 0 or −46 mV conditions, but was inhibited in Trx2 Tg MEFs under the same conditions. Furthermore, Nrf2-regulated gene expression was significantly increased in the WT MEFs, but not in the Trx2 Tg MEFs. These results show that the Cys/CySS redox status in the extracellular compartment regulates intracellular ROS generated primarily in the mitochondria, which play an important role in the activation of Nrf2 and up-regulation of antioxidant and detoxification systems.

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35

Xu, Yan, Yue Hua Wen, Jie Cheng, Gao Ping Cao, and Yu Sheng Yang. "Electrochemical Reaction Mechanism of Tiron in Acidic Aqueous Solution." Advanced Materials Research 396-398 (November 2011): 1730–35. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.1730.

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Electrochemical oxidation of tiron in the presence of H2O as a nucleophile in strongly acidic aqueous solutions was studied by cyclic voltammetry, controlled-voltage coulometry and spectrometric investigations. The mechanism of electrochemical reaction is confirmed by spectrophotometric tracing in various times of controlled-voltage coulometry. The voltammetric and spectrophotometric foundations indicate that a 1,4-Michael addition of H2O from its hydroxy moiety to the position 4 of electrochemically derived o-quinone is occurred. The electrochemical oxidation and reduction of tiron has been successfully accomplished by controlled-voltage coulometry in a redox flow-through type cell and the final electro-reduced product was characterized by spectrophotometric, 1H NMR and mass spectrometric methods. It is demonstrated that the electro-oxidation of tiron follows an ECE mechanism in acidic aqueous solutions, leading to formation of a new compound of para- benzoquinone derivative.

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36

TAMAHARA, Satoshi, Mutsumi INABA, Kota SATO, Naoaki MATSUKI, Yoshiaki HIKASA, and Ken-ichiro ONO. "Non-essential roles of cysteine residues in functional expression and redox regulatory pathways for canine glutamate/aspartate transporter based on mutagenic analysis." Biochemical Journal 367, no. 1 (October 1, 2002): 107–11. http://dx.doi.org/10.1042/bj20011843.

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A redox regulatory mechanism and a molecular link between oxidative and excitotoxic neurodegeneration have been postulated for high-affinity Na+-dependent glutamate transporters. In the present study, mutations were introduced at three cysteine residues in canine glutamate/aspartate transporter (GLAST) to investigate the functional significance of thiol groups in response to oxidation. Cys(-) GLAST, in which all cysteines were replaced by other amino acids, as well as other mutants with disruption of one of three cysteine residues, showed insoluble oligomer formation, which was considered to be due to spontaneous and excessive oxidation as observed in wild-type GLAST. The mutant transporters also showed plasma-membrane localization and glutamate-transport kinetics that were very similar to those of wild-type GLAST. Glutamate-transport activities in COS-7 cells transfected with wild-type and Cys(-) GLAST were inhibited to the same degree when cells were exposed to Hg2+ and were recovered by the addition of thiol-specific reductant dithiothreitol. These findings suggest that cysteine residues are not critical in functional expression of GLAST and the redox-sensing pathway via glutamate transporters.

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37

Chen, Fang-Fang, Yu-Yung Chang, Chao-Cheng Cho, and Chun-Hua Hsu. "Crystallization of the C-terminal redox domain of the sulfur-assimilatory enzyme APR1 fromArabidopsis thaliana." Acta Crystallographica Section F Structural Biology Communications 70, no. 9 (August 27, 2014): 1211–14. http://dx.doi.org/10.1107/s2053230x1401574x.

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Plant-type APS reductase (APR), which catalyzes the reduction of activated sulfate to sulfite in plants, consists of a reductase domain and a C-terminal redox domain showing sequence homology to thioredoxin but possessing the activity of glutaredoxin. In order to understand the structural and biochemical properties of the redox domain of plant-type APS reductase, the C-terminal domain of APR1 (APR1C) fromArabidopsis thalianawas crystallized using the sitting-drop vapour-diffusion method. X-ray diffraction data were collected to a resolution of 2.70 Å on the SPXF beamline BL13B1 at the NSRRC, Taiwan. The crystals belonged to space groupP43212 orP41212, with unit-cell parametersa=b= 58.2,c= 86.7 Å. With one molecule per asymmetric unit, the crystal volume per unit protein weight (VM) is 2.64 Å3 Da−1, which corresponds to a solvent content of approximately 53.49%. Further structure-based functional studies of APR1C would extend knowledge of the molecular mechanism and regulation of APR.

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38

Banks, William A. "The Blood-Brain Barrier Interface in Diabetes Mellitus: Dysfunctions, Mechanisms and Approaches to Treatment." Current Pharmaceutical Design 26, no. 13 (May 6, 2020): 1438–47. http://dx.doi.org/10.2174/1381612826666200325110014.

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Diabetes mellitus (DM) is one of the most common diseases in the world. Among its effects are an increase in the risk of cognitive impairment, including Alzheimer’s disease, and blood-brain barrier (BBB) dysfunction. DM is characterized by high blood glucose levels that are caused by either lack of insulin (Type I) or resistance to the actions of insulin (Type II). The phenotypes of these two types are dramatically different, with Type I animals being thin, with low levels of leptin as well as insulin, whereas Type II animals are often obese with high levels of both leptin and insulin. The best characterized change in BBB dysfunction is that of disruption. The brain regions that are disrupted, however, vary between Type I vs Type II DM, suggesting that factors other than hyperglycemia, perhaps hormonal factors such as leptin and insulin, play a regionally diverse role in BBB vulnerability or protection. Some BBB transporters are also altered in DM, including P-glycoprotein, lowdensity lipoprotein receptor-related protein 1, and the insulin transporter as other functions of the BBB, such as brain endothelial cell (BEC) expression of matrix metalloproteinases (MMPs) and immune cell trafficking. Pericyte loss secondary to the increased oxidative stress of processing excess glucose through the Krebs cycle is one mechanism that has shown to result in BBB disruption. Vascular endothelial growth factor (VEGF) induced by advanced glycation endproducts can increase the production of matrix metalloproteinases, which in turn affects tight junction proteins, providing another mechanism for BBB disruption as well as effects on P-glycoprotein. Through the enhanced expression of the redox-related mitochondrial transporter ABCB10, redox-sensitive transcription factor NF-E2 related factor-2 (Nrf2) inhibits BEC-monocyte adhesion. Several potential therapies, in addition to those of restoring euglycemia, can prevent some aspects of BBB dysfunction. Carbonic anhydrase inhibition decreases glucose metabolism and so reduces oxidative stress, preserving pericytes and blocking or reversing BBB disruption. Statins or N-acetylcysteine can reverse the BBB opening in some models of DM, fibroblast growth factor-21 improves BBB permeability through an Nrf2-dependent pathway, and nifedipine or VEGF improves memory in DM models. In summary, DM alters various aspects of BBB function through a number of mechanisms. A variety of treatments based on those mechanisms, as well as restoration of euglycemia, may be able to restore BBB functions., including reversal of BBB disruption.

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39

Sourav, Sagar, and Israel E. Wachs. "Cr-Free, Cu Promoted Fe Oxide-Based Catalysts for High-Temperature Water-Gas Shift (HT-WGS) Reaction." Catalysts 10, no. 3 (March 6, 2020): 305. http://dx.doi.org/10.3390/catal10030305.

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Анотація:

Ca, Ni, Co, and Ge promoters were examined as potential candidates to substitute for the current toxic Cr in Cu-promoted Fe oxide-based catalysts for the HT-WGS reaction. The Ca and Ni promoters were found to improve catalyst performance relative to promotion with Cr. The HS-LEIS surface analysis data demonstrate that Ca and Ge tend to segregate on the surface, while Ni, Co, and Cr form solid solutions in the Fe3O4 bulk lattice. The corresponding number of catalytic active sites, redox, and WGS activity values of the catalysts were determined with CO-TPR, CO+H2O-TPSR, and SS-WGS studies, respectively. The poorer HT-WGS performances of the Ge and Co promoters are related to the presence of surface Ge and Co that inhibits catalyst redox ability, with the Co also not stabilizing the surface area of the Fe3O4 support. The Ni promoter uniformly disperses the Cu nanoparticles on the catalyst surface and increases the number of FeOx-Cu interfacial redox sites. The Ca promoter on the catalyst surface, however, enhances the activity of the FeOx-Cu interfacial redox sites. The CO+H2O TPSR results reveal that the redox ability of the active sites follows the SS-WGS performance of the catalysts and show the following trend: 3Cu8CaFe > 3Cu8NiFe ≥ 3Cu8CrFe > 3Cu8CoFe >> 3Cu8GeFe. Furthermore, all the catalysts followed a redox-type reaction mechanism for the HT-WGS reaction.

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40

Senda, Miki, Shinya Kishigami, Shigenobu Kimura, Masao Fukuda, Tetsuo Ishida, and Toshiya Senda. "Molecular Mechanism of the Redox-dependent Interaction between NADH-dependent Ferredoxin Reductase and Rieske-type [2Fe-2S] Ferredoxin." Journal of Molecular Biology 373, no. 2 (October 2007): 382–400. http://dx.doi.org/10.1016/j.jmb.2007.08.002.

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41

Lesanavičius, Mindaugas, Daisuke Seo, and Narimantas Čėnas. "Thioredoxin Reductase-Type Ferredoxin: NADP+ Oxidoreductase of Rhodopseudomonas palustris: Potentiometric Characteristics and Reactions with Nonphysiological Oxidants." Antioxidants 11, no. 5 (May 19, 2022): 1000. http://dx.doi.org/10.3390/antiox11051000.

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Rhodopseudomonas palustris ferredoxin:NADP+ oxidoreductase (RpFNR) belongs to a novel group of thioredoxin reductase-type FNRs with partly characterized redox properties. Based on the reactions of RpFNR with the 3-acetylpyridine adenine dinucleotide phosphate redox couple, we estimated the two-electron reduction midpoint potential of the FAD cofactor to be −0.285 V. 5-Deaza-FMN-sensitized photoreduction revealed −0.017 V separation of the redox potentials between the first and second electron transfer events. We examined the mechanism of oxidation of RpFNR by several different groups of nonphysiological electron acceptors. The kcat/Km values of quinones and aromatic N-oxides toward RpFNR increase with their single-electron reduction midpoint potential. The lower reactivity, mirroring their lower electron self-exchange rate, is also seen to have a similar trend for nitroaromatic compounds. A mixed single- and two-electron reduction was characteristic of quinones, with single-electron reduction accounting for 54% of the electron flux, whereas nitroaromatics were reduced exclusively via single-electron reduction. It is highly possible that the FADH· to FAD oxidation reaction is the rate-limiting step during the reoxidation of reduced FAD. The calculated electron transfer distances in the reaction with quinones and nitroaromatics were close to those of Anabaena and Plasmodium falciparum FNRs, thus demonstrating their similar “intrinsic” reactivity.

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42

Hemmi, Hisashi, Yosuke Ikeda, Satoshi Yamashita, Toru Nakayama, and Tokuzo Nishino. "Catalytic mechanism of type 2 isopentenyl diphosphate:dimethylallyl diphosphate isomerase: verification of a redox role of the flavin cofactor in a reaction with no net redox change." Biochemical and Biophysical Research Communications 322, no. 3 (September 2004): 905–10. http://dx.doi.org/10.1016/j.bbrc.2004.08.013.

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43

Bergerhausen, Lukas, Julius Grosche, Juliane Meißner, Christina Hecker, Michele F. Caliandro, Christoph Westerhausen, Andrej Kamenac та ін. "Extracellular Redox Regulation of α7β Integrin-Mediated Cell Migration Is Signaled via a Dominant Thiol-Switch". Antioxidants 9, № 3 (10 березня 2020): 227. http://dx.doi.org/10.3390/antiox9030227.

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Анотація:

While adhering to extracellular matrix (ECM) proteins, such as laminin-111, cells temporarily produce hydrogen peroxide at adhesion sites. To study the redox regulation of α7β1 integrin-mediated cell adhesion to laminin-111, a conserved cysteine pair within the α-subunit hinge region was replaced for alanines. The molecular and cellular effects were analyzed by electron and atomic force microscopy, impedance-based migration assays, flow cytometry and live cell imaging. This cysteine pair constitutes a thiol-switch, which redox-dependently governs the equilibrium between an extended and a bent integrin conformation with high and low ligand binding activity, respectively. Hydrogen peroxide oxidizes the cysteines to a disulfide bond, increases ligand binding and promotes cell migration toward laminin-111. Inversely, extracellular thioredoxin-1 reduces the disulfide, thereby decreasing laminin binding. Mutation of this cysteine pair into the non-oxidizable hinge-mutant shows molecular and cellular effects similar to the reduced wild-type integrin, but lacks redox regulation. This proves the existence of a dominant thiol-switch within the α subunit hinge of α7β1 integrin, which is sufficient to implement activity regulation by extracellular redox agents in a redox-regulatory circuit. Our data reveal a novel and physiologically relevant thiol-based regulatory mechanism of integrin-mediated cell-ECM interactions, which employs short-lived hydrogen peroxide and extracellular thioredoxin-1 as signaling mediators.

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44

Finol-Urdaneta, Rocio K., Nina Strüver, and Heinrich Terlau. "Molecular and Functional Differences between Heart mKv1.7 Channel Isoforms." Journal of General Physiology 128, no. 1 (June 26, 2006): 133–45. http://dx.doi.org/10.1085/jgp.200609498.

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Ion channels are membrane-spanning proteins that allow ions to permeate at high rates. The kinetic characteristics of the channels present in a cell determine the cell signaling profile and therefore cell function in many different physiological processes. We found that Kv1.7 channels from mouse heart muscle have two putative translation initiation start sites that generate two channel isoforms with different functional characteristics, mKv1.7L (489 aa) and a shorter mKv1.7S (457 aa). The electrophysiological analysis of mKv1.7L and mKv1.7S channels revealed that the two channel isoforms have different inactivation kinetics. The channel resulting from the longer protein (L) inactivates faster than the shorter channels (S). Our data supports the hypothesis that mKv1.7L channels inactivate predominantly due to an N-type related mechanism, which is impaired in the mKv1.7S form. Furthermore, only the longer version mKv1.7L is regulated by the cell redox state, whereas the shorter form mKv1.7S is not. Thus, expression starting at each translation initiation site results in significant functional divergence. Our data suggest that the redox modulation of mKv1.7L may occur through a site in the cytoplasmic N-terminal domain that seems to encompass a metal coordination motif resembling those found in many redox-sensitive proteins. The mRNA expression profile and redox modulation of mKv1.7 kinetics identify these channels as molecular entities of potential importance in cellular redox-stress states such as hypoxia.

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45

Sha, Wenxin, Fei Hu, Yang Xi, Yudong Chu, and Shizhong Bu. "Mechanism of Ferroptosis and Its Role in Type 2 Diabetes Mellitus." Journal of Diabetes Research 2021 (June 28, 2021): 1–10. http://dx.doi.org/10.1155/2021/9999612.

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Ferroptosis is a novel form of nonapoptotic regulated cell death (RCD). It features iron-dependent lipid peroxide accumulation accompanied by inadequate redox enzymes, especially glutathione peroxidase 4 (GPX4). RAS-selective lethal 3 (RSL3), erastin, and ferroptosis inducing 56 (FIN56) induce ferroptosis via different manners targeting GPX4 function. Acyl-CoA synthetase long-chain family 4 (ACSL4), lysophosphatidylcholine acyltransferase 3 (LPCAT3), and lipoxygenases (LOXs) participate in the production of lipid peroxides. Heat shock protein family B member 1 (HSPB1) and nuclear receptor coactivator 4 (NCOA4) regulate iron homeostasis preventing ferroptosis caused by the high concentration of intracellular iron. Ferroptosis is ubiquitous in our body as it exists in both physiologic and pathogenic processes. It is involved in glucose-stimulated insulin secretion (GSIS) impairment and arsenic-induced pancreatic damage in the pathogenesis of diabetes. Moreover, iron and the iron-sulfur (Fe-S) cluster influence each other, causing mitochondrial iron accumulation, more reactive oxygen species (ROS) production, endoplasmic reticulum (ER) stress, failure in biosynthesis of insulin, and ferroptosis in β-cells. In addition, ferroptosis also engages in the pathogenesis of diabetic complications such as myocardial ischemia and diabetic cardiomyopathy (DCM). In this review, we summarize the mechanism of ferroptosis and especially its association with type 2 diabetes mellitus (T2DM).

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46

Song, Xiaohan, Xu Han, Rui Zhang, Hong Liu, and Jiang Wang. "Rhodium(III)-Catalyzed [4+2] Annulation via C-H Activation: Synthesis of Multi-Substituted Naphthalenone Sulfoxonium Ylides." Molecules 24, no. 10 (May 16, 2019): 1884. http://dx.doi.org/10.3390/molecules24101884.

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Анотація:

A convenient Rh(III)-catalyzed C-H activation and cascade [4+2] annulation for the synthesis of naphthalenone sulfoxonium ylides has been developed. This method features perfect regioselectivity, mild and redox-neutral reaction conditions, and broad substrate tolerance with good to excellent yields. Preliminary mechanistic experiments were conducted and a plausible reaction mechanism was proposed. The new type naphthalenone sulfoxonium ylides could be further transformed into multi-substituted naphthols, which demonstrates the practical utility of this methodology.

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47

Mansell, J., J. E. Drewes, and T. Rauch. "Removal mechanisms of endocrine disrupting compounds (steroids) during soil aquifer treatment." Water Science and Technology 50, no. 2 (July 1, 2004): 229–37. http://dx.doi.org/10.2166/wst.2004.0132.

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The objective of this study was to determine the primary removal mechanisms of endocrine disruptors such as steroidal hormones present in reclaimed water, specifically 17b-estradiol, estriol, and testosterone, during groundwater recharge via soil aquifer treatment (SAT). Steroidal hormones were quantified using enzyme-linked immunosorbent assays. Bench-scale studies and laboratory-scale soil column experiments were employed to determine what mechanisms (i.e., adsorption, biodegradation, photolytic degradation) dominate the removal of the three compounds of interest during SAT. Findings of these studies revealed that the dominating removal mechanism for the compounds of interest during SAT is adsorption to the porous media matrix and additional attenuation to below the detection limit occurred in the presence of bioactivity. This additional removal occurred regardless of dominating redox conditions (aerobic vs. anoxic) or the type of organic carbon matrix present (hydrophobic acids, hydrophilic carbon vs. colloidal carbon).

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48

Leung, Joseph-Hang, Hong-Thai Nguyen, Shih-Wei Feng, Sofya B. Artemkina, Vladimir E. Fedorov, Shang-Chin Hsieh, and Hsiang-Chen Wang. "Characteristics of P-Type and N-Type Photoelectrochemical Biosensors: A Case Study for Esophageal Cancer Detection." Nanomaterials 11, no. 5 (April 21, 2021): 1065. http://dx.doi.org/10.3390/nano11051065.

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P-type and N-type photoelectrochemical (PEC) biosensors were established in the laboratory to discuss the correlation between characteristic substances and photoactive material properties through the photogenerated charge carrier transport mechanism. Four types of human esophageal cancer cells (ECCs) were analyzed without requiring additional bias voltage. Photoelectrical characteristics were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–vis reflectance spectroscopy, and photocurrent response analyses. Results showed that smaller photocurrent was measured in cases with advanced cancer stages. Glutathione (L-glutathione reduced, GSH) and Glutathione disulfide (GSSG) in cancer cells carry out redox reactions during carrier separation, which changes the photocurrent. The sensor can identify ECC stages with a certain level of photoelectrochemical response. The detection error can be optimized by adjusting the number of cells, and the detection time of about 5 min allowed repeated measurement.

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49

Lev, Sophie, Ruthi Hadar, Paolo Amedeo, Scott E. Baker, O. C. Yoder, and Benjamin A. Horwitz. "Activation of an AP1-Like Transcription Factor of the Maize Pathogen Cochliobolus heterostrophus in Response to Oxidative Stress and Plant Signals." Eukaryotic Cell 4, no. 2 (February 2005): 443–54. http://dx.doi.org/10.1128/ec.4.2.443-454.2005.

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ABSTRACT Redox sensing is a ubiquitous mechanism regulating cellular activity. Fungal pathogens face reactive oxygen species produced by the host plant's oxidative burst in addition to endogenous reactive oxygen species produced during aerobic metabolism. An array of preformed and induced detoxifying enzymes, including superoxide dismutase, catalases, and peroxidases, could allow fungi to infect plants despite the oxidative burst. We isolated a gene (CHAP1) encoding a redox-regulated transcription factor in Cochliobolus heterostrophus, a fungal pathogen of maize. CHAP1 is a bZIP protein that possesses two cysteine-rich domains structurally and functionally related to Saccharomyces cerevisiae YAP1. Deletion of CHAP1 in C. heterostrophus resulted in decreased resistance to oxidative stress caused by hydrogen peroxide and menadione, but the virulence of chap1 mutants was unaffected. Upon activation by oxidizing agents or plant signals, a green fluorescent protein (GFP)-CHAP1 fusion protein became localized in the nucleus. Expression of genes encoding antioxidant proteins was induced in the wild type but not in chap1 mutants. Activation of CHAP1 occurred from the earliest stage of plant infection, in conidial germ tubes on the leaf surface, and persisted during infection. Late in the course of infection, after extensive necrotic lesions were formed, GFP-CHAP1 redistributed to the cytosol in hyphae growing on the leaf surface. Localization of CHAP1 to the nucleus may, through changes in the redox state of the cell, provide a mechanism linking extracellular cues to transcriptional regulation during the plant-pathogen interaction.

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50

Martin, Andrew J., Iain McDonald, Christopher J. MacLeod, Hazel M. Prichard, and Katie McFall. "Extreme enrichment of selenium in the Apliki Cyprus-type VMS deposit, Troodos, Cyprus." Mineralogical Magazine 82, no. 3 (April 15, 2018): 697–724. http://dx.doi.org/10.1180/mgm.2018.81.

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ABSTRACTThe Troodos ophiolite Cyprus hosts the type locality for Cyprus-type, mafic volcanogenic massive sulfide (VMS) deposits. Regional soil geochemical data for Troodos are highly variable with the Solea graben, one of three regional graben structures on Cyprus, showing enrichment in Te and Se. Of the three VMS sampled within the Solea graben, Apliki exhibits the most significant enrichment in Se. Samples from the South Apliki Breccia Zone; a zone of hematite-rich breccia containing euhedral pyrite and chalcopyrite, contain up to 4953 and 3956 ppm Se in pyrite and chalcopyrite, respectively. Four paragenetic stages are identified at Apliki and different generations of pyrite are distinguishable using trace-element chemistry analysed via laser ablation inductively coupled plasma mass spectrometry. Results indicate stage I pyrite formed under reduced conditions at high temperatures >280°C and contains 182 ppm (n = 22 σ = 253) Se. Late stage III pyrite which is euhedral and overprints chalcopyrite and hematite is enriched in Se (averaging 1862 ppm; n = 23 σ = 1394). Sulfide dissolution and hematite formation displaced large amounts of Se as hematite cannot accommodate high concentrations of Se in its crystal structure. The mechanisms proposed to explain the pronounced change in redox are twofold. Fault movement leading to localized seawater ingress coupled with a decreasing magmatic flux that generated locally oxidizing conditions and promoted sulfide dissolution. A Se/S ratio of 9280 indicates a probable magmatic component for late stage III pyrite, which is suggested as a mechanism explaining the transition from oxidizing back to reduced conditions. This study highlights the significance of changes in redox which promote sulfide dissolution, mobilization and enrichment of Se.

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