Prolongation of oxidative stress by long-lived reactive protein species induced by X-ray radiation and their genotoxic action

Abstract The formation of long-lived reactive protein species of bovine serum albumin (BSA), ovalbumin, casein and casein hydrolyzate with a half-life of 3-5 hours was shown using chemiluminescence induced by X-ray radiation. It was found that long-lived reactive protein species are capable of generating reactive oxygen species (ROS) (H(2)O(2), OH(?), HO(2)(?, 1)O(2)) in the aquatic environment over a long period of time in vitro. The interaction of X-ray-irradiated BSA with DNA in vitro led to the formation of 8-oxoguanine (8-oxo-7,8-dihydroguanine), a biomarker of oxidative damage to DNA. Some natural antioxidants are effective scavengers of ROS (inosine, tryptophan, methionine and ascorbate). They protect DNA from the action of long-lived reactive protein species leading to ROS generation and the formation of 8-oxoguanine. The intravenous injection of X-ray radiation-induced, long-lived reactive protein species to rats, as well as the peroral and intraperitoneal administration of these products to mice, gave rise to cytogenetic injuries in the cells of their red bone marrow through the formation of micronuclei in polychromatophilic erythrocytes. The administration of the same natural antioxidants used for in vitro experiments soon after irradiation made it possible to effectively eliminate the genotoxic action of oxidative stress caused by radiation-induced, long-lived reactive protein species. Our data represent clear evidence that the oxidative damage to proteins induced by X-rays is directly involved in the induction of a response to DNA damage in rodents.     

Guanosine and inosine as natural geneprotectors for mice blood cells exposed to X-rays

The radioprotective effects of guanosine and of inosine on bone marrow cells of mice exposed to acute X-rays (1.5 Gy) were studied by using the micronuclear test. The guanosine and inosine (riboxine) decrease the frequency of micronucleated polychromatic erythrocytes and significantly recover erythropoiesis. Also, radioprotective effects of the guanosine and of the inosine on the irradiated leucocytes of mice were tested by the alkaline comet assay. Was shown that purine ribonucleosides diminish quantity of DNA damage and activates repair processes in leucocytes under irradiation of blood and animals. The reactive oxygen species induced by ionizing radiation perform essential role in DNA damaging. Using a sensitive method of enhanced chemiluminescence in a peroxidase-luminol-p-iodophenol system for quantitative measurement of hydrogen peroxide and coumarin-3-carboxylic acid for quantitative measurement of hydroxyl radicals we have shown that guanosine and inosine essentially decrease the yield of hydrogen peroxide and hydroxyl radicals in X-ray-irradiated water. The results obtained indicate that radioprotective properties of guanosine and inosine (riboxine) in the blood cells are operative at the genome level.     

Pegasys: software for executing and integrating analyses of biological sequences

Background  

We present Pegasys – a flexible, modular and customizable software system that facilitates the execution and data integration from heterogeneous biological sequence analysis tools.     

Oxygen effect in heat-induced DNA damage

The major kinds of heat-induced damage to DNA (depurination, guanine oxidation to 8-oxoguanine, cytosine deamination to uracil) were shown to depend in their extent on the oxygen content in solution. Formation of hydrogen peroxide in water upon heating was enhanced in the presence of D₂O and decreased by various scavengers of singlet oxygen, corroborating the involvement of ¹O₂ in the thermal generation of reactive oxygen species. The aggregate data indicate that all kinds of heat-induced DNA damage in solution arise through this common mechanism.     

First report of Phytopythium vexans causing the “Avocado sadness” in Michoacan,Mexico

Mexico is the main producer, consumer and exporter of avocado in the world, being Michoacan the main producer state contributing more than 80% of the national production. There are phytopathogens that decimate the production causing the death of the tree. Root samples were collected in avocado trees that showed the characteristic symptomatology of the disease known as avocado sadness, the sampling was carried out in four of the main avocado producing towns, in the state of Michoacan, Mexico. The isolation consisted in sowing root tissue in Petri dishes with V8^®-PARPH culture medium, subsequently they were identified morphologically and for species level it was determined by molecular biology, with the PCR-ITS technique. Pathogenicity tests were performed in triplicate with avocado seedlings with more than six leaves. After 24 hours, the inoculated plants expressed decay in the apical part, after 120 hours the leaves showed yellowing and after 15 days there was a generalized wilt on the stem and leaves, re-isolating the phytopathogen Phytopythium vexans. This study confirms the first report of the oomycete P. vexans affecting avocado trees in the most important producing region of the Mexican Republic.     

Knockout of SlTOM1 and SlTOM3 results in differential resistance to tobamovirus in tomato

During tobamovirus–host coevolution, tobamoviruses developed numerous interactions with host susceptibility factors and exploited these interactions for replication and movement. The plant‐encoded TOBAMOVIRUS MULTIPLICATION (TOM) susceptibility proteins interact with the tobamovirus replicase proteins and allow the formation of the viral replication complex. Here CRISPR/Cas9‐mediated mutagenesis allowed the exploration of the roles of SlTOM1a, SlTOM1b, and SlTOM3 in systemic tobamovirus infection of tomato. Knockouts of both SlTOM1a and SlTOM3 in sltom1a/sltom3 plants resulted in an asymptomatic response to the infection with recently emerged tomato brown rugose fruit virus (ToBRFV). In addition, an accumulation of ToBRFV RNA and coat protein (CP) in sltom1a/sltom3 mutant plants was 516‐ and 25‐fold lower, respectively, than in wild‐type (WT) plants at 12 days postinoculation. In marked contrast, sltom1a/sltom3 plants were susceptible to previously known tomato viruses, tobacco mosaic virus (TMV) and tomato mosaic virus (ToMV), indicating that SlTOM1a and SlTOM3 are not essential for systemic infection of TMV and ToMV in tomato plants. Knockout of SlTOM1b alone did not contribute to ToBRFV and ToMV resistance. However, in triple mutants sltom1a/sltom3/sltom1b, ToMV accumulation was three‐fold lower than in WT plants, with no reduction in symptoms. These results indicate that SlTOM1a and SlTOM3 are essential for the replication of ToBRFV, but not for ToMV and TMV, which are associated with additional susceptibility proteins. Additionally, we showed that SlTOM1a and SlTOM3 positively regulate the tobamovirus susceptibility gene SlARL8a3. Moreover, we found that the SlTOM family is involved in the regulation of plant development.     

Pathways of degradation of organic components of waste water of (meth)acrylate-producing factories to methane by communities of microorganisms of adapted and unadapted sludge]

Pathways of the degradation of the main compounds of (meth)acrylate-producing factories wastewater (methyl methacrylate, methyl and butyl acrylate, acrylate and methacrylate, acetone, isopropanol, butanol and methanol) by the anaerobic microbial consortium of mesophilic unadapted granulated sludge from the "UASB" reactor and of adapted activated sludge from the contact reactor were comparatively studied. It was shown that the degradation of fatty acids and alcohols took place in both types of sludge. Methacrylate, acrylate and acetone degradation occurred only in adapted sludge. Both types of sludge were characterized by the reversible conversion of acetone and isopropanol and by the presence of the isomeric transition of butyrate and isobutyrate too. The present results allow to suggest that the adaptation of activated sludge to substrate includes the accumulation of biomass of microorganisms capable of hydrolyze specific substrates into such general intermediates as low-molecular-weight fatty acid and alcohols further metabolized to methane and carbon dioxide.     

The genotoxic action of uranyl ions on DNA in vitro caused by the generation of reactive oxygen species

8-Oxoguanine (8-OG) is an important biomarker of oxidative DNA damage induced by reactive oxygen species (ROS). By using ELISA with monoclonal antibodies against 8-OG, the formation of 8-OG in DNA by the action of uranyl ions, gamma-irradiation, and heating at 37 degrees C and their combined action was investigated in view of environmental pollution by uranium oxides as a result of the use of armor piercing shells with depleted uranium. The content of 8-OG in DNA induced by the action of gamma-irradiation, 5 microM uranyl ions and heating changes with time in a complicated manner. These results suggest that, by the action of uranyl ions, an additional generation of ROS occurs, which leads both to the formation of 8-OG in DNA and its further oxidation. Uranyl ions at a conceptration of 5 microM increase the thermal deamination of cytosine in DNA several times but do not influence DNA thermal depurination. It is shown that uranyl ions essentially increase the production of hydrogen peroxide and hydroxyl radicals by the action of heat on water. The results indicate a high chemical genotoxicity of uranyl ions and their enhancing effect on DNA base damage by the action of heat and gamma-irradiation.