Over the last decade fundamentally new features have been revealed for the participation of glutathione and glutathione-dependent enzymes (glutathione transferase and glutaredoxin) in cell ...proliferation, apoptosis, protein folding, and cell signaling. Reduced glutathione (GSH) plays an important role in maintaining cellular redox status by participating in thiol-disulfide exchange, which regulates a number of cell functions including gene expression and the activity of individual enzymes and enzyme systems. Maintaining optimum GSH/GSSG ratio is essential to cell viability. Decrease in the ratio can serve as an indicator of damage to the cell redox status and of changes in redox-dependent gene regulation. Disturbance of intracellular GSH balance is observed in a number of pathologies including cancer. Consequences of inappropriate GSH/GSSG ratio include significant changes in the mechanism of cellular redox-dependent signaling controlled both nonenzymatically and enzymatically with the participation of isoforms of glutathione transferase and glutaredoxin. This review summarizes recent data on the role of glutathione, glutathione transferase, and glutaredoxin in the regulation of cellular redox-dependent processes.
Cellular redox homeostasis involves a combination of redox processes and corresponding regulatory systems and represents an important factor ensuring cell viability. Redox-dependent regulation of ...cellular processes is a multi-level system including not only proteins and enzyme complexes, but also non-coding RNAs, among which an important role belongs to microRNAs. The review focuses on the involvement of miRNAs in the redox-dependent regulation of both ROS (reactive oxygen species)-generating enzymes and antioxidant enzymes with special emphasis on the effects of miRNAs on redox-dependent processes in tumor cells. The impact of ROS on the miRNA expression and the role of the ROS/miRNA feedback regulation in the cell redox state are discussed.
Among the key antioxidant enzymes, thioredoxin and glutaredoxin systems play an important role in cell defense against oxidative stress and maintenance of redox homeostasis owing to the regulation of ...thiol--disulfide exchange. The thioredoxin isoforms Trx1 (cytoplasmic form) and Trx2 (mitochondrial form) can reduce inter- and intramolecular disulfide bonds in proteins, in particular, in oxidized peroxiredoxins, which disrupt organic hydroperoxides, H₂O₂, and peroxynitrite. NADPH-dependent thioredoxin reductase, which reduces a broad range of substrates including oxidized form of thioredoxin, can also directly reduce lipid hydroperoxides, H₂O₂, and dehydroascorbic and lipoic acids. Glutaredoxin, whose major isoforms in mammals are Grx1, Grx2, and Grx5, as well as thioredoxin, catalyzes S-glutathionylation and deglutathionylation of proteins to protect SH-groups from oxidation and restore functionally active thiols. However, in contrast to thioredoxin, glutaredoxin reduces GSH-mixed disulfides and catalyzes the reaction not only via a dithiol mechanism but also via monothiol reduction. In addition to the role in cellular antioxidant defense, all of the reviewed redox proteins (thioredoxin, thioredoxin reductase, peroxiredoxin, and glutaredoxin) have a number of significant functions required for cell viability: they regulate transcription factor activities, play the role of growth factors, serve as enzyme cofactors, take part in regulation of cell cycle, and are involved in antiapoptotic mechanisms.
Closed-shell atoms scattered from a metal surface exchange energy and momentum with surface phonons mostly via the interposed surface valence electrons, i.e., via the creation of virtual ...electron-hole pairs. The latter can then decay into surface phonons via electron-phonon interaction, as well as into acoustic surface plasmons (ASPs). While the first channel is the basis of the current inelastic atom scattering (IAS) surface-phonon spectroscopy, no attempt to observe ASPs with IAS has been made so far. In this study we provide evidence of ASP in Ni(111) with both Ne atom scattering and He atom scattering. While the former measurements confirm and extend so far unexplained data, the latter illustrate the coupling of ASP with phonons inside the surface-projected phonon continuum, leading to a substantial reduction of the ASP velocity and possibly to avoided crossing with the optical surface phonon branches. The analysis is substantiated by a self-consistent calculation of the surface response function to atom collisions and of the first-principle surface-phonon dynamics of Ni(111). It is shown that in Ni(111) ASP originate from the majority-spin Shockley surface state and are therefore collective oscillation of surface electrons with the same spin, i.e. it represents a new kind of collective quasiparticle: a Spin Acoustic Surface Plasmon (SASP).
Background Preservation of anatomic integrity and function of the cranial nerves during the removal of skull base tumors is one of the most challenging procedures in endoscopic endonasal surgery. It ...is possible to use intraoperative mapping and identification of the cranial nerves in order to facilitate their preservation. The purpose of this study was to evaluate the effectiveness of intraoperative trigger electromyography in prevention of iatrogenic damage to the cranial nerves. Methods Twenty three patients with various skull base tumors (chordomas, neuromas, pituitary adenomas, meningiomas, cholesteatomas) underwent mapping and identification of cranial nerves during tumor removal using the endoscopic endonasal approach in Department of Neurooncology of Federal State Autonomous Institution “N.N. Burdenko National Medical Research Center of Neurosurgery” of the Ministry of Health of the Russian Federation from 2013 to 2018. During the surgical interventions, mapping and identification of the cranial nerves were carried out using electromyography in triggered mode. The effectiveness of the method was evaluated based on a comparison with a control group (41 patients). Results In the main group of patients, 44 nerves were examined during surgery using triggered electromyography. During the study, the III, V, VI, VII, and XII cranial nerves were identified intraoperatively. Postoperative cranial nerve deficiency was observed in 5 patients in the study group and in 13 patients in the control group. The average length of hospitalization was 9 days. Conclusion We did not receive statistically significant data supporting the fact that intraoperative identification of cranial nerves using trigger electromyography reduces the incidence of postoperative complications in the form of cranial nerve deficits (p = 0.56), but the odds ratio (0.6) suggests a less frequent occurrence of complications in the study group. Based on our experience, the trigger electromyography methodology appears quite promising and requires further research.
The effect of curcumin on the resistance of SKOV-3 human ovarian adenocarcinoma cells to cisplatin was studied. It was found that curcumin induced “reversal” of cancer cells resistance, which was ...associated with suppression of the expression of genes encoding the key antioxidant enzymes (
SOD1
,
SOD2
,
CAT
,
GPX1
, and
HO-1
) and transcription factor Nrf2 and a decrease in the expression of genes encoding kinases of the PI3K/Akt/mTOR signaling pathway. The obtained results confirm the role of redox-dependent regulation in the “reversal” of cancer cells resistance to cisplatin.
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•Endohedral fullerenes with paramagnetic encapsulated atoms are new magnetic materials.•They have new vibrational frequencies not associated with empty fullerenes.•The vibrational ...spectrum depends considerably on the encapsulated atom’s spin state.
Endohedral fullerenes with paramagnetic encapsulated atoms are new magnetic materials of interest for numerous applications from medicine to quantum computers. An important phenomenon with endohedral fullerenes is the appearance of new vibrational frequencies not associated with empty fullerenes. The vibrational spectra of the lanthanide endohedral fullerenes La@C60 and Ce@C60 in various spin states are calculated using the density functional method. Most of the spectral lines lie in the 300–1600 cm-1range, and their intensities change dramatically depending on the molecule’s symmetry and spin state, which are determined by the encapsulated lanthanide atom. The average frequency shift of the carbon cage vibrations caused by spin transition is only 5 cm-1. The calculated frequencies of the coupled “metal–carbon cage” vibrations of the lanthanide endohedral fullerenes La@C60 and Ce@C60 in various spin states lie in the 10–170 cm-1range. The computational results for both the frequencies and intensities of the metal–cage modes depend considerably on the spin state. The changes in these vibrational modes are due to the changes in the molecular symmetry and the metal–carbon bond lengths. Such dependence can be used as a basis for controlling the spin state of metallofullerenes by measuring the vibration frequencies in the far-infrared zone, which could be important for nanoelectronics and quantum informatics.
Abstract
Precision laboratory measurements are presented for 135 O
i
lines in the infrared (including 51 lines not measured previously in the laboratory) using time-resolved Fourier transform ...infrared spectroscopy in the 800–13,000 cm
−1
region. The fine structure of some lines is observed for the first time. Using our linelist together with all relevant measurements from other works, we perform a re-optimization of O
i
level energies to obtain an internally consistent system of 2
p
3
4
S
nl
levels. Some O
i
level energies measured long ago are corrected. We also present a long list of oscillator strengths calculated with the help of quantum defect theory.
Background. Hordeum bulbosum L. is the only wild species of the genus Hordeum , the gene pool of which is successfully used in introgressive hybridization to increase the genetic diversity of ...H. vulgare L. When creating introgression forms based on hybrids of H. vulgare with H. bulbosum , it is necessary to take into consideration the ploidy of the parent species, and their genetic features that determine the intensity of the process of H. bulbosum chromosomes elimination in embryogenesis. The purpose of our investigation was to study the features associated with the elimination of bulbous barley chromosomes in embryos obtained in various combinations of crosses involving the tetraploid hybrid H. bulbosum with H. vulgare for its effective use in obtaining introgression lines of H. vulgare . Material and methods. The analysis was performed on 9-15 days old embryos obtained in crosses of the tetraploid hybrid F2 ( H. bulbosum A17 (4x) × H. vulgare ‘Borwina’ (4x)) (HbHbHvHv) with ‘Igri’ (2x) and ‘Borwina’ (2x) barley varieties, with H. bulbosum A17 (4x), as well as during its self-pollination. The chromosomal composition of embryos of different ages was analyzed on squashed embryo slides using genomic in situ hybridization (GISH). Results. Among the 11-15 days old embryos obtained from self-pollination of the hybrid, approximately half of the studied ones were mixoploids, while in other embryos the majority of cells contained only the genomic material of H. vulgare . The elimination process was very intensive in crosses of the hybrid with the barley varieties ‘Igri’ (2x) and ‘Borwina’ (2x), and by day 10-11 after pollination cells containing only the genomic material of H. vulgare predominated in all embryos, regardless of the direction of crossing and the variety used. Hybrid embryos with a stable chromosomal composition resulted from a cross of a tetraploid hybrid with H. bulbosum A17 (4x). Embryos with recombinant H. vulgare chromosomes carrying alien genetic material of bulbous barley were identified in all types of crosses. Conclusion. The most efficient way for the mass production of introgression lines of cultivated barley varieties based on the partially fertile hybrid F2 ( H. bulbosum A17 (4x) × H. vulgare ‘Borwina’ (4x)), is the crossing with varieties of H. vulgare (2x). The progeny from such crosses will contain only cultivated barley plants, among which it is possible to identify forms with the introgression of H. bulbosum and use already the first generation from their self-pollination for selecting H. vulgare lines carrying the genetic material of bulbous barley in both homologs.
•The mathematical model of a gas bubble growth in high-viscosity liquids is presented.•The half-analytical solution of the problem is obtained.•It is shown that after a certain time solution of the ...problem becomes self-similar.•The time-dependencies of concentration profile and bubble growth rate are found.
The present paper describes the growth dynamics of a gas bubble formed as a result of nucleation in a highly-viscous gas-saturated liquid under rapid decompression. The mathematical model presented combines both dynamical and diffusion problems. The half-analytical solution for the dissolved gas concentration profile, bubble growth rate and the rate of bubble mass change is found. In contrast to previously reported solutions, it can be applied at all stages of the process in a wide range of supersaturation. The half-analytical solution is in good agreement with the results of numerical simulations and with known solutions for limiting cases.
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