Cysteine Homeostasis Disturbance in Escherichia coli Caused by Exposure to Ciprofloxacin.

E. coli exposure to ciprofloxacin disturbs cysteine homeostasis; an increase in the intracellular concentration of cysteine is dangerous due to its ability to enhance ROS generation. Unlike wild-type bacteria, in which the cysteine content did not exceed the control level, cells of the gshA mutant lacking glutathione are characterized by increased concentration of intracellular cysteine in proportion to the concentrations of the antibiotic, despite the intensive export of cysteine into the medium. At low concentrations of ciprofloxacin, the mutant strain formed half as many colonies as the parent strain in the survival test. These findings attest to the important role of the incorporation of excess cysteine into glutathione as one of the mechanisms of cysteine homeostasis during the stress response to antibiotic.

[Changes in the Activity of Antioxidant Systems of Escherichia coli under Phosphate Starvation].

Changes in the activity of antioxidant systems in Escherichia coli during phosphate starvation have been studied. It is shown that starvation was accompanied by a decrease in the intensity of respiration, an increase in the rate of superoxide production, and a decrease in the level of ATP. Simultaneously, there was a decrease in H2O2 in the medium and a significant increase in the expression of the katG and katE genes which encode the HPI and HPII catalases, respectively. At the same time, there was no drop in the membrane potential, which may indicate the retention of normal membrane activity in starving cells. It has been shown for the first time that the transition of E. coli to phosphate starvation is accompanied by significant changes in the status of glutathione. The most important of these are associated with a decrease in the level of reduced glutathione in the medium (GSHout) and with a simultaneous increase in its content in the cytoplasm (GSHin), as well as a shift in the GSHin to oxidized glutathione form (GSSGin) ratio towards reductive values, and GSHout/GSSGout towards oxidative values. Among the mutants used in the work, the gor trxB double mutant, which is deficient in the synthesis of glutathione reductase and thioredoxin reductase, showed the most pronounced distinctive features. Compared to the parental strain, this mutant showed a multiple higher expression of katG::lacZ, the highest level of oxidized intra- and extracellular glutathione, and, accordingly, the lowest GSH/GSSG ratio in both compartments. In general, the data we obtained indicate that during phosphate starvation the interaction of the glutathione redox-system and regulons that control protection against reactive oxygen species creates conditions that allow maintaining the concentration of ROS below the toxic level. As a result, phosphate-starved E. coli cells can maintain high viability for a long period of time, which allows them to quickly resume growth after the addition of phosphate.

[Justification of the need to introduce an additional criterion to the assessment of the nutrition status of military personnel].

Currently, in accordance with the regulations of the Government of the Russian Federation and the Ministry of Defense of the Russian Federation, the main indicator for assessing nutritional status is the body mass index, which does not take into account the component composition of the body. At the same time, it is necessary to assess in more detail the composition of the body of military personnel, that is, the ratio of its muscle and fat components. The purpose of the study is the scientific and methodological substantiation of the need to introduce an additional criterion for assessing the nutritional status of military personnel, that characterize body composition - the body fat percentage. Material and methods. The study involved 1.373 male military personnel aged 18 to 53 who underwent a medical examination. The following methods were used: anthropometry, bioimpedancemetry, caliperometry. Results. Various methods for determining the fat component of the body have been studied. The analysis of the data obtained showed that all methods for determining the body fat percentage have highly significant correlations among themselves and with bioimpedancemetry data. All coefficients had high reliability p<0.001 at r>0.7. When the values of the body mass index deviate from the normative ones, it is proposed to use the indicator of the body fat percentage to clarify the assessment of the nutritional status of male military personnel. Based on the data obtained, modern algorithms for assessing the nutritional status of military personnel have been developed for use in the practice of military health care at various levels of medical support for military personnel. Conclusion. As a result of a prospective study, the need to introduce an additional criterion for assessing the nutritional status of male military personnel was substantiated and proved, and calculation methods for assessing the fat component of the body, comparable with bioimpedancemetry data, were determined. Algorithms for determining the nutritional status of servicemen for different levels of medical support have been developed. In conditions where special devices for determining the fat component of the body are not included in the supply standards of the medical service, it is recommended to calculate the body fat percentage by girth methods using a centimeter tape.

Nonselective Expression of Short-Wavelength Cone Opsin Improves Learning in Mice with Retinal Degeneration in a Visually Guided Task.

The study explored the potential of an animal opsin nonselectively expressed in various neuronal elements of the degenerative retina to restore the impaired visual function. A knockout murine model of inherited retinal dystrophy was used. Mice were injected intravitreally with either a virus carrying the gene of short-wavelength cone opsin associated with a reporter fluorescent protein or a control virus carrying the sequence of a modified fluorescent protein with enhanced membrane tropism. Viral transduction induced pronounced opsin expression in ganglion, bipolar, and horizontal retinal neurons. Behavioral testing included the visually guided task in the trapezoid Morris water maze and showed a partial recovery of the learning ability in the mice whose retinas had been transduced with cone opsin.

Effect of Changes in the Redox Status on Biofilm Formation in Escherichia coli.

Changes in the redox balance in the medium and in Escherichia coli cells significantly affect the ability of bacteria to form biofilms. An increase in the level of aeration in the culture of wild-type bacteria led to a 3-fold decrease in the mass of biofilms. Mutants lacking components of the glutathione and thioredoxin redox systems, as well as transporters involved in the transmembrane cycling of glutathione, demonstrated increased biofilm formation ability. The effect of exogenous glutathione on biofilm formation depended on the culturing conditions. The addition of 0.1-1 mM Trolox (a water-soluble analog of vitamin E) was accompanied by a 30-40% reduction in biofilm formation.

[The selection of optimal methods for determining the perfect body weight for the assessment of the nutritional status].

In everyday practice, for a personalized approach to assessing nutritional status it is necessary to determine the ideal body weight of a person, but bio-impedance analysis of body composition widespread in stationary conditions in an outpatient setting is not always available. Therefore, it is necessary to use other methods for determining the ideal body weight, the results of which would be most comparable with bio-impedance analysis results. The aim of the work is a comparative analysis of various calculation methods for determining the ideal body weight and the results of bio-impedance testing. Material and methods. 830 men aged 18 to 44 years were examined. The ideal body weight was calculated by 16 common methods. The obtained results were compared with bio-impedance analysis of body composition. Results and discussion. To compare the accuracy of the coincidence of the results obtained by means of the used methods, the method of standard error of the model was used, as well as the correlation analysis was carried out, and regression models were constructed. A comparative analysis revealed the most informative methods for determining the ideal body weight, which are recommended for use in practice. Conclusion. As a result of comparing several methods for determining the ideal body weight, we can conclude that the methods closest to the determination of ideal body weight obtained by bio-impedancemetry are the methods of Borgardt, Monnerot-Dumayn and the Insurance Company "Metropolitan Life".

[The participation of religious organizations in formation of population attitude to transplantation of organs and tissues].

The article discusses issue of possibility of influence of religious organizations on the attitude of population to issues of human organ transplantation. The attitude of followers of different religions to key issues of bioethics related to organ donation and transplantation is analyzed. It is concluded that there are no definite prohibitions on implementing this kind of medical intervention in modern religious regulations. The study of results of questionnaire survey of two groups of respondents revealed certain part of population, whose decision on the issues of posthumous organ donation would be influenced by the opinion of representative of religious organization. It is established that every tenth respondent appealed to the Orthodox priest when making decision to sign consent paper concerning posthumous exempt of organ from relatives. It is concluded that it is possible to affect the formation in certain part of population understanding of need to support organ donation and transplantation in case of active work in this direction of representatives of religious organizations.

Bicistronic Construct for Optogenetic Prosthesis of Ganglion Cell Receptive Field of Degenerative Retina.

To perform optogenetic prosthetics of the retinal ganglion cell receptive field, a bicistronic genetic construct carrying the genes encoding the excitatory (channelrhodopsin-2) and inhibitory (Guillardia theta anion channelrhodopsin GtACR2) rhodopsins was created. A characteristic feature of this construct was the combination of these two genes with a mutant IRES insertion between them, which ensures the exact ratio of expression levels of the first and second genes in each transfected cell. Illumination of the central part of the neuron with light with a wavelength of 470 nm induced the action potential generation in the cell. Stimulation of the peripheral neuronal region with light induced the inhibition of action potential generation. Thus, using optogenetics methods, we simulated the ON-OFF interaction in the retinal ganglion cell receptive field. Theoretically, this construct can be used for optogenetic prosthetics of degenerative retina in the case of its delivery to the ganglion cells with lentiviral vectors.

Influence of pharmacological preconditioning on the results of lifting operations efficiency.

The main aim of the study is to determine the effectiveness and safety of lifting operations in women with varying degrees of involuntary changes of facial skin, in particular when applying pharmacological conditioning, with the objectification of the role of the latter. MATERIALS AND METHODS: A research and surgical treatment were conducted to eliminate involutional changes of various degrees in the facial skin of 461 women aged 35-75 years. Surface lifting was performed in 20.2% of patients, SMAS-lifting - 49.0%, SMAS-lifting with a three-level endoscopic assist lift of the lower face zone was performed in 30.8% of women. Before the surgery in 13.2% of cases, I degree of involutional changes in facial skin was registered, 47.9% - grade II, 38.9% - grade III. Patients were divided into two comparable groups. With the standard preparation without additional drug correction, 299 women (64.9%) were operated on in the preoperative period, they made up a comparison group. The main group included 162 (35.1%) women who underwent therapeutic conditioning before the lifting operation (Cytoflavin, n = 86; Actovegin n = 23; Ethylmethylhydroxypyridine succinate, n = 32; Meldonium, n = 21; Pentoxifylline, n = 31; Vinpocetine n = 27). Instrumental evaluation of the skin dermal microcirculation was performed using laser Doppler flowmetry and estimation of transcutaneous oxygen tension. In the blood plasma, the parameters of free radical processes (FRP) were studied. FRP were studied in terms of generation of active oxygen forms by leukocytes - intensity of chemiluminescence basal and intensity of chemiluminescence stimulated, as well as antiperoxide plasma activity and malondialdehyde. Early postoperative complications were analyzed, the number of repeated lifting surgical corrections on the face was studied for 5 years. RESULTS: The role of FRP in the pathogenesis of involuntary changes in the facial skin has been established. The imbalance of FRP was expressed in the intensification of the reactive oxygen species generation and products of lipid peroxidation. This correlated with disorders of cutaneous microcirculation and a decrease in the saturation of the facial tissues with oxygen, manifested by an increasing energy deficit and the severity of involutional skin changes. The obtained data justify the expediency of using pharmacological conditioning with energy correcting antioxidant medicine. Preoperative conditioning allowed to reduce the number of early postlifting complications associated with tissue trophism in a quarter, especially during surface lifting. In addition, in the preconditioning group, the scar was more cosmetic already at the seventh day after the operation. Based on the study of postoperative catamnesis, self-assessment data and laboratory-instrumental methods of skin system examination in people of different ages, it was revealed that while using SMAS-lifting with a three-level endoscopic-assisted lifting of the lower part of the face, the lowest frequency of complications and the best 5-year effectiveness were established.

[The Attitude of Physicians of Donor Bases to Problems of Transplantation of Human Organs and Tissues].

The article considers social aspects of transplantology on the basis of analysis of data of questionnaire survey of 266 physicians of donor bases of the Federal Center implementing transplantation of human organs and tissues. The respondents were representatives of the most prevalent medical professions and ll age gender groups. According to study results, physicians are aware of importance of development of organs and tissues transplantation in the region though take a very passive standing related to informing transplantation specialists about availability of a potential donor. The involvement of physicians in the transplantation program in the first place depends on position of administration of medical institution. At the same time, 44,3±3,1% of physicians are aware of such the most important normative legal principle regulating possibility of postmortem intake of organs as consent presumption. Less than 18,6±2,4% of physicians support this standard. Half of the respondents are ready, in case of their instant death, to become donors of organs and are ready too in case of such a proposal to sign consent to possible postmortem donorship. Therefore, one of conditions of development of organs and tissues transplantation in the region is implementation of explanatory work with medical community targeted to increasing of motivation of personnel of donor bases to active interaction with transplantology specialists.

Biodistribution of Alpha-Fetoprotein-Containing Noncovalent Complex Aimpila with Antitumor Activity.

Biodistribution of [125I]Aimpila (20 mg/kg) in the tumor and normal tissues, including the mammary gland tissue, after single oral dose was studied in BALB/c nude mice with T47D/ReCAF+++ human breast tumor sensitive to this drug and in closely related BALB/c nude+mice without tumors. The maximum concentration of [125I]Aimpila was in fact the same in the tumor and in the mammary gland, while the time course of its accumulation/elimination differed. The time of the maximum accumulation of the drug in the tumor was shorter and its persistence longer than in normal tissue. After 24 h, label concentration in the tumor was 4.5 times higher (p=0.002). Differences in the time course of label accumulation in the tumor were detected. The maximum ratio of tumor/blood concentrations of the preparation was recorded in 1 h after administration. [125I]Aimpila and [125I]alpha-fetoprotein accumulated in the tumor in comparable concentrations and were eliminated simultaneously at the same rate. The results of comparative analysis of accumulation of the labeled compounds in Aimpila-sensitive T47D/RECAF+++ tumor from 0.5 to 9.0 h after drug administration could be interpreted as a result of possible receptor-mediated binding of the complex with the tumor at the expense of the alpha-fetoprotein transporting part. Differences in the parameters of [125I]Aimpila biodistribution in the tumor and normal mammary tissue indirectly attested to selective antiproliferative activity of the complex.

Chloride conducting light activated channel GtACR2 can produce both cessation of firing and generation of action potentials in cortical neurons in response to light.

Optogenetics is a powerful technique in neuroscience that provided a great success in studying the brain functions during the last decade. Progress of optogenetics crucially depends on development of new molecular tools. Light-activated cation-conducting channelrhodopsin2 was widely used for excitation of cells since the emergence of optogenetics. In 2015 a family of natural light activated chloride channels GtACR was identified which appeared to be a very promising tool for using in optogenetics experiments as a cell silencer. Here we examined properties of GtACR2 channel expressed in the rat layer 2/3 pyramidal neurons by means of in utero electroporation. We have found that despite strong inhibition the light stimulation of GtACR2-positive neurons can surprisingly lead to generation of action potentials, presumably initiated in the axonal terminals. Thus, when using the GtACR2 in optogenetics experiments, its ability to induce action potentials should be taken into account. Our results also open an interesting possibility of using the GtACR2 both as cell silencer and cell activator in the same experiment varying the pattern of light stimulation.

The effect of 20-hydroxyecdysone on the susceptibility of Escherichia coli to different antibiotics.

AIMS: The aim of this study was to investigate the influence of 20-hydroxyecdysone (20E) on the susceptibility of growing Escherichia coli to antibiotics. METHODS AND RESULTS: Susceptibility of E. coli to antibiotics in the presence of 20E was estimated by determination of the colony-forming ability and the specific growth rate. Pretreatment with 20E decreased the bactericidal effect of ciprofloxacin (0·3 and 3·0 µg ml-1 ), streptomycin (10 and 40 µg ml-1 ) and kanamycin (10 µg ml-1 ) and increased the bactericidal action of 0·03 µg ml-1 ciprofloxacin. To study the influence of 20E on gene expression, we used strains of E. coli carrying fusions of promoters of relevant genes with the structural gene of ß-galactosidase. 20E had no marked effect on the expression of antioxidant genes katG, katE, sodA and the rpoS gene (general stress response), while it (alone or combined with ciprofloxacin) markedly stimulated expression of the sulA gene belonging to the SOS regulon (DNA damage response). CONCLUSION: In growing E. coli, 20E modulated the bactericidal action of antibiotics and stimulated the SOS response. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study may be used to enhance the efficiency of antibacterial therapies.

[Role of Thiol Redox Systems in Escherichia coli Response to Thermal and Antibiotic Stresses].

Isogenic knockout mutants of Escherichia coli deficient in components of the glutathione and thioredoxin redox systems and growing at various temperatures (20-46°C) exhibited considerable differences in growth rate and survival, as well as in expression of the antioxidant genes. In the parent strain E. coli BW25113 (wt) treated with ciprofloxacin, ampicillin, or streptomycin, dependence of survival from growth temperature was a V-shaped curve with the maximum sensitivity within the range corresponding to high growth rates (40-44°C). Significant inverse correlation was observed between log CFU at different temperatures and specific growth rate prior to antibiotic addition. This applied to most of the mutants, which exhibited higher resistance to the three antibiotics tested at nonoptimal temperatures (20 and 46°C) than at 37 and 40°C. No correlation was found between resistance to stress and antibiotics and expression of the antioxidant genes. The role of global regulators ppGpp and σ(s) in E. coli resistance to antibiotics and nonoptimal temperatures was shown.

Comparative characteristics of two anion-channel rhodopsins and prospects of their use in optogenetics.

Anion-selective opsins slow ChloC and ACR2 were expressed in rat brain cortical neurons by electroporation in utero. It is shown that the light-activated channel ACR2 has pronounced advantages in terms of both the inactivation kinetics and the neuron inhibition intensity, which is associated with a more negative value of the light-activated current reversal potential compared to the slow ChloC channel. The identified properties of opsin ACR2 indicate that it can be used for strictly controlled suppression of neuronal activity in optogenetic experiments, including the expression in the retinal ganglionic cells for reconstituting the OFF-component of their receptive field, which is essential for optogenetic prosthetics of degenerative retina.

Effects of allogenic fetal pancreatic tissue transplantation on regeneration of islet cells in recipient rats with alloxan-induced diabetes mellitus.

The linear parameters and number of Langerhans islets were evaluated in rats with alloxaninduced diabetes mellitus after transplantation of fetal pancreatic tissue to the anterior chamber of the eye. The islets significantly increased in size by week 3 after surgery and a trend to an increase in their number was observed.

Vanadate reduction by Pseudomonas aeruginosa strains.

The ability of three Pseudomonas aeruginosa strains to reduce vanadate under microaerophilic conditions has been studied. It has been demonstrated that P. aeruginosa strains A17, A03 and C25a were able to reduce up to 38-60% pentavalent vanadium present in the medium. Vanadate reduction by P. aeruginosa strains A17, A03 and C25a was not associated with anaerobic respiration. It has been shown that vanadate reduction by P. aeruginosa strains is not the result of the spontaneous process. This is the first report of stimulation of vanadate reduction by ATPase activity inhibitor N-N-dicyclohexylcarbodiimide under aerobic conditions.

[Chromate reduction by Pseudomonas sp. str. 10 in the presence of some heavy metals and alternative electron acceptors].

Pseudomonas sp. str. 10 reduces chromate with a rate of 0.54 mg / L.h. The availability of Cd2+ and Zn2+ in the medium has no noticeable effect on the rate or slightly increases it. The presence of nickel and copper in the ionic form in the medium resulted in a decrease of chromate reduction rate 2.4 and 4.2 times, respectively. Change of these metals into hydroxide form significantly lowers their negative influence. Iron (III) both in ionic and hydroxide form inhibits the reduction of chromate by Pseudomonas sp. 10. Joint presence of all studied metals decreases their negative impact on chromate reduction, therefore these metals may be neutralized together without a significant lowering of the process efficacy on condition that copper-containing drain will be cleaned separately. The presence of alternative acceptors of electrons inhibited the reduction of chromate. Sulfate and oxyanions of chlorine - chlorate and perchlorate have the highest inhibitory effect on chromate reduction.

[Metabolism features of bacteria resistant to high concentrations of chromate].

Twenty strains of bacteria resistant to high concentrations of chromate were isolated from different ecological niches. They were able to reduce chromate to compounds of trivalent chromium--nonsoluble chromium hydroxide or soluble crystalline hydrates of trivalent chromium. The growth features of these microorganisms on media containing chromate at high concentrations (up to 20.0 g/l) are described. Besides chromate bacteria can reduce vanadate to compounds of V(4+) and Mo(6+) to Mo(5+). The best reduction takes place on the media where MPB. glucose or ethanol serves as the source of carbon. The growth and reduction of anion-in-study did not occur on organic acids. It was shown that tungstate, chlorate or perchlorate were not toxic for the studied bacteria up to concentrations of 10.0 g/l, however were not reduced by these microorganisms. The most active strains belong to genera Pseudomonas, Oerskovia, Bacillus, Micrococcus.

[Study of the accidental thymus involution during the formation of hierarchic communities by a novel physical method for recording the social stress].

A novel method for recording the aggressive behavior in newly formed hierarchic communities has been developed. A temporal and age-related dynamics of the accidental thymus involution in mammals has been studied.