Interaction of the Fluorophenyl Analog of Retinal with Proteorhodopsin from Exiguobacterium sibiricum

Abstract—

We have developed an alternative method for the synthesis of an analog of natural retinal, which contains the p-fluorophenyl fragment instead of the trimethylcyclohexene ring. The proposed scheme for the synthesis of the target all-E-isomer of the target retinoid consists of using C5-phosphonate that contains the terminal nitrile group under Horner–Emmons reaction conditions. It has been shown that this scheme is more efficient and provides a higher total yield of the target product than the previously described variant. The procedure has been developed for the preparation of an analog of microbial proteorhodopsin ESRh from Exiguobacterium sibiricum, which contains a modified chromophore. It has been found that, as in the case of bacterioopsin from Halobacterium salinarum, the replacement of the trimethylcyclohexene ring in the natural chromophore by the p-fluorophenyl fragment does not prevent the formation of the artificial pigment F-Phe-ESRh from proteorhodopsin ESRh, which preserves the cycle of photochemical reactions. Certain differences have been found between the properties of native recombinant ESRh and its analog F-Phe-ESRh including a shift in the absorption maximum to the short-wavelength region, the formation of M intermediate at lower pH values, the presence of “long-lived M,” and a general slowdown in the photocycle. The reduced stability of the resulting proteorhodopsin analog F-Phe-ESRh to prolonged exposure to visible light has been also demonstrated.

Thermoheliox: effect on the functional hemodynamics of the human brain

A kinetic study of the effect of thermoheliox (inhalation of a helium and oxygen mixture, 70 °C) on the functional hemodynamics of the human brain by functional magnetic resonance imaging was carried out. The dynamic responses of the BOLD signal were found to be biphasic. An empirical equation describing the first phase of the hemodynamic response to visual stimulus was proposed. It was shown that preliminary inhalation of thermoheliox stimulates the hemodynamic responses by slowing down the vasoconstriction.

Hydrogen inhalation in rehabilitation program of the medical staff recovered from COVID-19

Active hydrogen inhalation (H(H2O)m) has powerful antioxidant and antiapoptotic effects. In recent years, it has been used in a number of experimental and clinical studies.

Aim. To study the safety and effectiveness of inhalation of the “active form of hydrogen” (AFV;(H(H2O)m)) in the rehabilitation program of coronavirus disease 2019 (COVID-19) survivors during the recovery period.

Material and methods. This randomized controlled parallel prospective study included 60 COVID-19 survivors with post-COVID-19 syndrome (ICD-10: U09.9) during the recovery period, with clinical manifestations of chronic fatigue syndrome (CFS), who received standard therapy in accordance with the management protocol of patients with CFS (ICD-10: G93.3): physiotherapy and medication therapy with drugs containing magnesium, B vitamins and L-carnitine. The patients were divided into 2 groups. The experimental group (n=30) included patients who received hydrogen inhalation for 90 minutes every day during 10 days (SUISONIA hydrogen inhalation device, Japan). The control group (n=30) consisted of patients who received standard therapy. In both groups, patients were comparable in sex and mean age: in the experimental group — 53 (22; 70) years, in the control group — 51 (25; 70) years. Biological markers of systemic inflammation, oxygen transport, lactate metabolism, intrapulmonary shunting, 6-minute walk test, and vascular endothelial function were determined in all patients on the 1st and 10th days of follow-up.

Results. In the experimental group, a decrease in following parameters was revealed: stiffness index (SI), from 8,8±1,8 to 6,8±1,5 (p<0,0001); ALT, from 24,0±12,7 to 20,22±10,61 U/L (p<0,001); venous blood lactate, from 2,5±0,8 to 1,5±1,0 mmol/L (p<0,001); capillary blood lactate, from 2,9±0,8 to 2,0±0,8 mmol/L (p<0,0001); estimated pulmonary shunt fraction (Qs/Qt, Berggren equation, 1942) from 8,98±5,7 to 5,34±3,2 (p<0,01); white blood cells, from 6,64±1,57 to 5,92±1,32 109/L. In addition, we revealed an increase in the refractive index (RI) from 46,67±13,26% to 63,32±13,44% (p<0,0001), minimum blood oxygen saturation (SpO2) from 92,25±2,9 to 94,25±1, 56% (p<0,05), direct bilirubin from 2,99±1,41 to 3,39±1,34 pmol/L (p<0,01), partial oxygen tension (PvO2) from 26,9±5,0 to 34,8±5,6 mm Hg (p<0,0001), venous oxygen saturation (SvO2) from 51,8±020,6 to 61,1±018,1% (p<0,05), partial capillary oxygen tension (PcO2) from 48,7±15,4 to 63,8±21,2 mm Hg (p<0,01), capillary oxygen saturation (ScO2) from 82,2±4,2 to 86,2±4,8% (p<0,01), distance in 6 minute walk test from 429±45,0 to 569±60 m.

Conclusion. Inhalation therapy with H(H2O)m in the rehabilitation program of COVID-19 survivors during the recovery period is a safe and highly effective method. Manifestations of silent hypoxemia and endothelial dysfunction decreased, while exercise tolerance increased. As for laboratory tests, a decrease in the white blood cell count, estimated pulmonary shunt fraction and lactate content parameters was revealed.

Thermovaccination: Thermoheliox as an Immune Response Stimulant. Kinetics of Antibodies and C-Reactive Protein Synthesis in Coronaviral Infection

The high efficiency of using thermoheliox (inhalation with a high-temperature mixture of helium and oxygen) in the treatment of patients affected by COVID-19 was shown. The dynamics of accumulation of IgG, IgM, and C-reactive protein (CRP) in patients with coronavirus infection in the “working” and control groups was studied experimentally. It was shown that thermoheliox intensifies the synthesis of IgG, IgM, and CRP antibodies, while eliminating the induction period on the kinetic curves of the synthesis of specific antibodies in the IgG form and transfers the synthesis of CRP to a fast phase. The results of experiments confirm the previously obtained data based on the analysis of the kinetic model of the development of coronaviral infection in the human body.

Computer Modeling of N-Acetylglutamate Synthase: From Primary Structure to Elemental Stages of Catalysis

Three-dimensional full-atom model of the enzyme complex with acetyl-CoA and substrate was constructed on the basis of the primary sequence of amino acid residues of N-acetyl glutamate synthase. Bioinformatics approaches of computer modeling were applied, including multiple sequence alignment, prediction of co-evolutionary contacts, and ab initio folding. On the basis of the results of calculations by classical molecular dynamics and combined quantum and molecular mechanics (QM/MM) methods, the structure of the active site and the reaction mechanism of N-acetylglutamate formation are described. Agreement of the structures of the enzyme-product complexes obtained in computer modeling and in the X-ray studies validates the reliability of modeling predictions.

Thermovaccination, thermoheliox as a stimulant of immune response. Kinetic model of process development

A kinetic model is proposed to describe the key features of development of an acute viral infection, accumulation of antibodies, and immune response in the human body. The general features of immune system stimulation by thermoheliox are described. The model can be used for developing the basis for the application of thermoheliox in the treatment of patients affected by coronavirus.

Kinetic model of development of acute viral infection in the human body. Critical conditions, control mechanisms, "thermoheliox"

A kinetic model of the development of acute viral infection is proposed and the dynamic behavior of key variables, including the concentrations of viral particles, infected cells, and pathogenic microorganisms, is described. The change in the hydrogen ion concentration in the lungs and pH dependence of the activity of carbonic anhydrase, a key respiration enzyme, are critical factors. An acute bifurcation transition determining either the life or collapse of the system is demonstrated. The transition is associated with exponential increase in the concentrations of participants in the process and with functioning of the key enzyme, carbonic anhydrase. A physicochemical interpretation is given for the therapeutic effect of temperature rise and potential therapeutic effect of “thermoheliox”, that is, breathing by heated helium-oxygen mixture.

[Thermal heliox proteome. High-temperature heliox does not cause destruction of human respiratory system cells]

AIM

Conducting a pilot study to assess the effect of thermal heliox on the state of the respiratory tract by studying of the exhaled breath condensate protein composition before the thermal heliox procedure, immediately after and after three hours of relaxation Materials and methods. A comparative study of the exhaled breath condensates (EBC) protein composition of five non-smoking healthy donors was carried out. The EBC was taken before the respiratory procedure, immediately after a 20-minute inhalation by mixture of He/O2 gases (70/30) heated to 70C and 3 hours later. The protein composition was determined by chromatography-mass spectrometric analysis after selective tryptic hydrolysis. The results were processed using the Mascot program and the UniProt database.

RESULTS

After the heliox procedure, the volume of the collected condensate (11.5 ml) decreases by an average of 32% and is practically restored after three hours of relaxation. Most proteins were consistent for all samples, regardless of the thermal heliox procedure. These are keratins, several proteins of the immune system (immunoglobulins, compliment proteins), tubulin. In samples after thermal heliox, the appearance of small amounts of additional proteins is observed. These are proteins of muscle metabolism (actin and calmodulin), fibrinogen, traces of hemoglobin, apolipoprotein, type B creatine kinase. After three hours of relaxation, tubulin disappears in the EBC.

CONCLUSION

Most exhaled proteins are the same before, after the procedure, and for three hours of relaxation. The results obtained demonstrate the relative safety of the use of high temperature heliox as a therapeutic agent.

Kinetics of Chemical Processes in the Human Brain. The Cholinergic Synapse-Mechanisms of Functioning and Control Methods

In the framework of the kinetic model, the functioning of the cholinergic synapse is considered. The results of mathematical modeling of changes in the level of acetylcholine, induced pH impulse, the influence of the frequency of impulse transmission and inhibition of acetylcholinesterase are presented. Physicochemical explanation for a number of important physiological phenomena, such as neuromuscular paralysis, the molecular mechanism of neurological memory, and actions of nerve poisons and toxins, is given.

Kinetics of Chemical Processes in the Human Brain. Proton Blockade of Acetylcholinesterase and pH-Impulse in the Mechanism of Functioning of the Cholinergic Synapse

A kinetic model describing the dynamics of synaptic "discharge" taking into account the kinetics of the injection of the neurotransmitter into the synaptic cleft, the pH-dependence of the catalytic activity of the enzyme, and diffusion withdrawal of protons is proposed. The model provides a physicochemical explanation for a number of important physiological phenomena, such as the neuromuscular paralysis, the molecular mechanism of neurological memory, and the effect of some neurotoxins and drugs.

Dynamics of in Vivo Metabolites Concentrations in Posttraumatic Period of Human Brain. 1H MRS Study

For the first time the intracellular concentrations of N-acetylaspartate (NAA), aspartate (Asp), and glutamate (Glu) were measured in human brain in vivo, and the effect of severe traumatic brain injury on NAA synthesis in acute and remote posttraumatic phases was revealed. In non-damaged (MRI-negative) lobes the next day after injury, Asp and Glu decreased by 45% and 35%, respectively, while NAA decreased only by 16%. A negative correlation between NAA and Asp/Glu ratio was found. The Glu level returned to the norm long after injury, Asp remained below the norm by 60%, NAA decreased by 65% relative to the norm, and Asp/Glu decreased significantly. The results obtained educe the leading role of neuronal aspartate-malate shuttle in NAA synthesis alterations.

Kinetic Instability of Zero Steady State As a Fundamental Cause of Low Efficiency of Chemotherapy of Cancer

Using mathematical modeling of the process of cancer treatment by the classical chemotherapy methods and therapy with biological agents, the effect of the kinetic parameters of the model on the final outcome of treatment was studied. It is established that the complete cure (i.e., the formation of a stable steady state with a zero number of cancer cells) cannot be reached by means of only classical chemotherapy.

Kinetics of DNA elongation

A mathematical model of the DNA elongation stage is proposed, and a formula for calculating the characteristic time of doubling a DNA strand consisting of a large numbers of nucleotides was derived. It is shown that, when the number of nucleotides is greater than 50, it is fair to use a linear dependence of the elongation time on the number of nucleotides. Calculations of the DNA elongation time for a number of organisms are given.

(1)H-MRS and MEGA-PRESS pulse sequence in the study of balance of inhibitory and excitatory neurotransmitters in the human brain of ultra-high risk of schizophrenia patients

The MEGA-PRESS pulse sequence was used for determination of overlapping signals in the (1)H-MRS spectra of the human brain. For the first time, the balance of GABA glutamate/glutamine concentrations was estimated quantitatively in the human brain of patients with ultra-high risk of schizophrenia. It was found that GABA concentration and GABA/GLX ratios were significantly reduced in the left frontal lobe of UHR subjects.

[Proteomic analysis of exhaled breath condensate for diagnosis of pathologies of the respiratory system]

Study of the proteomic composition of exhaled breath condensate (EBC), is a promising non-invasive method for the diagnosis of the respiratory tract diseases in patients. In this study the EBC proteomic composition of the 79 donors, including patients with different pathologies of the respiratory system has been investigated. Cytoskeletal keratins type II (1, 2, 3, 4, 5, 6) and cytoskeletal keratins the type I (9, 10, 14, 15, 16) were invariant for all samples. Analyzing the frequency of occurrence of proteins in different groups of examined patients, several categories of protein have been recognized: found in all pathologies (Dermcidin, Alpha-1-microglobulin, SHROOM3), found in several pathologies (CSTA, LCN1, JUP, PIP, TXN), and specific for a single pathology (PRDX1, Annexin A1/A2). The EBC analysis by HPLC-MS/MS can be used to identify potential protein markers characteristic for pathologies such as chronic obstructive pulmonary disease (PRDX1) and pneumonia (Annexin A1/A2).