E. V. Mashkina

Comparative Analysis of Thermotolerance of Sunflower Chlorophyll Mutants

The influence of high temperatures on sunflower chlorophyll mutants was studied. The tolerance criteria were the level of chromosome aberrations and the mitotic index in the root apical meristem of seedlings, the level of nucleus-free cells in the epidermis of cotyledonous leaves, and the intensity of chlorophyll accumulation after the action of heat shock (HS). In addition, the frequency of plants with an altered content of pigments in M1 and M2 was analyzed. The results indicated that the plastomic mutant en-chlorina-5 is more tolerant to temperature stress as compared to other sunflower lines.

Effect of Allantoin on the Activity of Enzymes Providing Regulation of the ROS-Dependent Status of an Organism

In most vertebrates, intermediate products of purine degradation play the role of molecular quenchers of free radicals. Many authors regard these products as a specific level of systemic antioxidant protection. Carbon dioxide and ammonia are terminal products of enzymatic degradation of purines (e.g., adenine) in fish and amphibians. It is well known that certain intermediate products of this process (uric acid, urea, etc.) are effective antioxidants [1]. In most mammals, this cascade of reactions includes the stage at which urate oxidase catalyzes conversion of uric acid into allantoin (glyoxyl diureide). However, urate oxidase is absent in primates (including humans). As a result, the allantoin concentration in human blood plasma is an order of magnitude lower than in blood plasma of other mammals. According to the results reported by different researchers, these values are 4.4–37.9 and 50–150 mM, respectively [2–4]. The allantoin found in primates either comes from allantoin-containing food or is synthesized as a result of uric acid interaction with free radicals [5, 6]. Therefore, intake of pure allantoin would be expected to increase the antioxidant status of the organism. The goal of this work was to study the effects of allantoin on the level of products of lipid peroxidation (LPO), activity of antioxidant enzymes, and repair systems in tissues of animals exposed to oxidative stress. Nonpurebred white male rats weighing 180–200 g were used. Oxidative stress was simulated by exposure to increased pressure of oxygen (hyperbaric oxygenation, HBO) at 0.5 MPa for 2 h. Experimental animals were divided into four groups, eight animals each. The first group contained intact control rats. The second group was exposed to HBO at 0.5 MPa for 2 h. The animals of the third group received three intraperitoneal injections of an allantoin solution (24, 12, and 1 h before decapitation). The antioxidant efficiency of several concentrations of allantoin was preliminarily tested in vitro using chemiluminescence analysis. An optimum concentration of 0.08 mg of allantoin per 100 g body weight was used in further experiments. To test the protective effect of allantoin, the animals of the fourth group received three intraperitoneal injections of the optimal dose of allantoin (24, 12, and 1 h before exposure to HBO).

Effect of Plastoquinone Derivative 10(6 'Plastoquinonyl)decyltriphenylphosphonium (SkQ1) on Contents of Steroid Hormones and NO Level in Rats

Introduction of the plastoquinone derivative 10-(6′-plastoquinonyl)decyltriphenylphosphonium (SkQ1) into male Wistar rats once a day for two weeks in doses of 25 and 250 nmol/kg led to elevation of 17ß-estradiol level in blood serum by 33 and 41%, respectively. At the same time, nitrate and nitrite contents in the rat blood serum increased by 49 and 34%, respectively. ESR spectroscopy with diethyldithiocarbamate-iron complex as a spin trap showed more than twofold increase in NO production in lungs, but not in blood, liver, and intestines, following the SkQ1 daily introduction at a dose of 25 nmol/kg.

Testing the Concept of the Interatomic Status of the NFE2L2/AP1 Pathway as a Systemic Biomarker for Examination Stress

Background and ObjectivesOxidative status-based interactomic profiling is a promising approach for fundamental integrative cell biology, diagnostics, and therapy. However, this approach has been neither utilized as a method nor tested as a tool. Thus, we aimed (1) to develop an oxidative status pathway state assessment-based analytical procedure relying on NFE2L2/AP1 pathway evaluation, and (2) to preliminarily assess its responsiveness, performance and diagnostic properties when applied to deciphering stress conditions of the academic examination period and academic term. These conditions were chosen as those representing a common model of mild, everyday-life stressors causing shifts in oxidative status.MethodsTo meet the aim of the study, we performed a repetitive-measurements study collating gene expression of NFE2L2/AP1 pathway targets and controllers under the two stress conditions using semi-quantitative reverse transcription-polymerase chain reaction.ResultsSurprisingly, even with some sensitivity limitations of the methods employed, a pathway state analysis approach based on a multiple target-to-controller ratio calculation was highly responsive and yielded very high receiver operating characteristics in deciphering the model stress conditions.ConclusionAlthough further testing of the approach is required, the interactomic pathway activation assaying concept was preliminarily experimentally proven to be a highly promising clinical diagnostic tool that may easily be adapted for current tasks.

Antimutagenic activity of mitochondria-targeted plastoquinone derivative

The ability of cationic plastoquinone derivative 10-(6′-plastoquinonyl) decyltriphenylphosphonium (SkQ1) to modify processes of spontaneous and induced mutagenesis was studied. It is shown that daily introduction of this compound into male Wistar rats in doses of 25 and 250 nmol/kg during two weeks decreases spontaneous level of chromosome aberrations in anaphase in the eye cornea from 0.39 ± 0.09 to 0.13 ± 0.08 and 0.14 ± 0.05, respectively. The level of 8-hydroxy-2′-deoxyguanosine in blood serum of the investigated animals decreases from 32.12 ± 1.55 to 25.90 ± 2.26 and 25.76 ± 1.50 ng/ml, respectively. These facts indicate that the decrease in spontaneous clastogenesis is caused by decreased level of DNA damage by endogenous reactive oxygen species. A higher dose of SkQ1 also decreases to control level chromosome aberrations caused by oxygen under pressure of 0.5 MPa for 60 min. It is also shown in experiments with bacterial biosensors that SkQ1 is able to efficiently protect cells against genotoxic effect of UV radiation at 300–400 nm.

Responses of Sunflower Chlorophyll Mutants to Increased Temperature and Oxidative Burst

A tolerance of nuclear, plastome, and mitochondrial mutants of sunflower (Helianthus annuus L.) to extreme factors, increased temperature and oxidative stress, which was simulated by hyperbaric oxygenation was studied. In model experiments, activities of superoxide dismutase and catalase were assayed; cytogenetic analysis was used for the assessments of proliferative activity of cells in the root meristem; in field experiments, seedling emergence and growth at the stage of 3–4 leaf pair were evaluated. Most tolerant to increased temperature and oxygen pressure were a plastome en:chlorina-5 mutant and a partial revertant pr6-en:chlorina-7 with a changed structure of mitochondrial DNA.

Modification of the Effect of Nitrosomethylurea on Sunflower Seedlings by Heat Shock

Separate and combined action of nitrosomethylurea (NMU) and heat shock (HS) on germination of seeds of the inbred line 3629 and derived nuclear and plastome mutant lines, n-chlorina-1 and en-chlorina-5, respectively, were studied. NMU at a concentration of 0.015%, as well as HS (40°C), had no effect on the spontaneous level of chromosome aberrations in root meristem of sunflower seedlings. However, at a concentration of 0.03%, the mutagen considerably increased the frequency of chromosome rearrangements. Pretreatment with heat for 30 min enhanced the cytogenetic effect of NMU (0.03%) on line 3629 seedlings. In the nuclear mutant, the reaction of root meristematic cells did not depend on the additional heat treatment. The combined action of HS and NMU at early germination stages had no effect on the survival of line 3629 plants and plastome mutant en-chlorina-5; the survival of n-chlorina-1 plants decreased. The highest frequency of M1plants with chlorophyllic abnormalities (green revertants, lethals, and variegated forms) was observed in n-chlorina-1 line.

Mutation processes in oxidative stress preadapted animals

The present paper deals with the problem of the preadaptation of the metabolic system of newborn rats to hyperbaric oxygenation (HBO) (0.2 MPa) induced oxidative stress, as well as with the assessment of the longevity of a metabolic track that is observed after such treatment. A possible increase in resistance of the animals to the oxidative stress induced by hyperbaric oxygenation (0.5 MPa) after preadaptation in the early neonatal period is discussed. Long-term mutation processes after preadaptation are studied. Changes in the reaction norm to oxidative stress in the progeny of reciprocal crossbreedings of preadapted rats are assessed.

The effect of oxidative stress on nitrosomethylurea-induced mutagenesis in sunflower Helianthus annuus L.

The effect of hyberbaric oxygenation on mutagenicity of nitrosomethylurea (NMU) was examined. It was shown that in the regimes studied, hyperbaric oxygenation enhances the NMU mutagenic effect on the plastid genetic material of sunflower. Possible mechanisms of the increase of NMU-induced mutagenesis by hyperbaric oxygenation are discussed.

Mutagenic Effect of Nitrosomethylurea Modified by Heat Shock at Early Stages of the Sunflower Seedlings Development

A comparative study of chlorophyll mutations induced in sunflower seedlings of the initial line 3629 and its nuclear and plastom mutant derivatives by nitrosomethylurea (NMU), heat shock (HS, 40°C), and their combination was performed. The spectrum and frequency of chlorophyll mutations depended on the treatment conditions and on the genotype of the lines tested. Nuclear mutant displayed highest sensitivity to NMU, HS, and their combination. The line 3629 plants displayed highest tolerance to NMU and HS. However, plastom mutants were more tolerant to the combination of the mutagens compared to the plants of the initial line.