Определение эффективности способов борьбы с асфальтеносмолопарафиновыми отложениями при эксплуатации нефтяных месторождений

В качестве объекта исследования – рассматривается нефтяные месторождения, а именно Талаканского месторождения, а предметом является технологии предупреждение асфальтеносмолопарафиновых отложений (АСПО) на нефтепромысловых оборудованиях. Цель работы – определение наиболее эффективного метода борьбы с асфальтеносмолопарафиновыми отложениями, и применение технологий удаления отложений на различных нефтяных месторождениях. В процессе исследования были раскрыты причины образования парафиновых отложений и эффективность применения некоторых методов борьбы с АСПО на месторождениях. Область применения: месторождения нефти и газа, имеющие осложнения в виде асфальтосмолопарафиновых отложений.The object of the study is the oil fields, namely the Talakan field, and the subject is the technologies for the prevention of asphaltene-tar-paraffin deposits (ASPO) on oilfield equipment. The purpose of the work is to determine the most effective method of controlling asphaltene-tar-paraffin deposits, and to apply technologies for removing deposits in various oil fields. In the course of the study, the reasons for the formation of paraffin deposits and the effectiveness of the use of some methods of combating ASPO in the fields were revealed. Field of application: oil and gas fields with complications in the form of asphalt-resin-paraffin deposits

Construction and molecular analysis of genetically modified C 3 plants expressing a glycolate oxidizing pathway inside the chloroplast

Metabolism of glycolate via the photorespiratory pathway in C3 plants consumes not only ATP and reducing equivalents but results also in approximately 25% loss of the carbon from glycolate. In the present study, a novel biochemical pathway for the metabolism of glycolate was established in the chloroplast of Arabidopsis thaliana plants. The new pathway aims to increase the CO2 concentration in the vicinity of Rubisco thereby suppressing photorespiration in C3 plants. The pathway is derived from E. coli and converts the glycolate formed during photorespiration into glycerate. Three enzymatic activities are required: glycolate dehydrogenase (GDH), glyoxylate carboligase (GCL), and tartronic semialdehyde reductase (TSR). The minimal E.coli glycolate dehydrogenase enzyme is formed from three different polypeptides. As an alternative, a glycolate dehydrogenase (AtGDH) derived from A. thaliana was used. Transgenic A. thaliana plants containing the necessary genes for the novel pathway were generated. Variable amounts of foreign proteins as well as RNA were detected by Western blot and RT-PCR, respectively. Enzymatic assays showed that the proteins are active in planta. Biochemical, physiological and biophysical analyses were performed under ambient and enhanced photorespiratory conditions using different transgenic lines for evaluating the impact of the novel pathway in planta. By measuring the Gly/Ser ratio, a clear reduction in photorespiration was observed in transgenic plants expressing the novel pathway genes compared to wild type plants. A clear decrease in the amount of CO2 released in the plant mitochondria during photorespiration was also obvious in transgenic lines. The ammonia release bioassay provides an additional evidence for the partial suppression of photorespiration in some of the transgenic lines. Furthermore, establishment of the glycolate pathway in the plant chloroplasts results in a decrease in the CO2 compensation point (Gamma*). The CO2 assimilation rates in transgenic plants were also enhanced under photorespiratory conditions. Finally, plant growth measurements revealed that the transgenic plants expressing the glycolate pathway in their chloroplasts have bigger leaf area as well as bigger rosette diameter compared to the control plants. Moreover, the total fresh and dry weight measurements showed that the total plant productivity was enhanced. Interestingly, most of the described effects were also observed in plants that only overexpressed a functional GDH. However, these effects were stronger in plants overexpressing all necessary elements of the glycolate pathway. Moreover, the phenotypical effects were much stronger when the bacterial GDH was compared to the plant GDH. Taken together, it can be concluded that expression of the novel pathway in C3 plant chloroplast does not only result in a reduction of photorespiration but it also enhances plant growth

Construction and molecular analysis of genetically modified C 3 plants expressing a glycolate oxidizing pathway inside the chloroplast

Metabolism of glycolate via the photorespiratory pathway in C3 plants consumes not only ATP and reducing equivalents but results also in approximately 25% loss of the carbon from glycolate. In the present study, a novel biochemical pathway for the metabolism of glycolate was established in the chloroplast of Arabidopsis thaliana plants. The new pathway aims to increase the CO2 concentration in the vicinity of Rubisco thereby suppressing photorespiration in C3 plants. The pathway is derived from E. coli and converts the glycolate formed during photorespiration into glycerate. Three enzymatic activities are required: glycolate dehydrogenase (GDH), glyoxylate carboligase (GCL), and tartronic semialdehyde reductase (TSR). The minimal E.coli glycolate dehydrogenase enzyme is formed from three different polypeptides. As an alternative, a glycolate dehydrogenase (AtGDH) derived from A. thaliana was used. Transgenic A. thaliana plants containing the necessary genes for the novel pathway were generated. Variable amounts of foreign proteins as well as RNA were detected by Western blot and RT-PCR, respectively. Enzymatic assays showed that the proteins are active in planta. Biochemical, physiological and biophysical analyses were performed under ambient and enhanced photorespiratory conditions using different transgenic lines for evaluating the impact of the novel pathway in planta. By measuring the Gly/Ser ratio, a clear reduction in photorespiration was observed in transgenic plants expressing the novel pathway genes compared to wild type plants. A clear decrease in the amount of CO2 released in the plant mitochondria during photorespiration was also obvious in transgenic lines. The ammonia release bioassay provides an additional evidence for the partial suppression of photorespiration in some of the transgenic lines. Furthermore, establishment of the glycolate pathway in the plant chloroplasts results in a decrease in the CO2 compensation point (Gamma*). The CO2 assimilation rates in transgenic plants were also enhanced under photorespiratory conditions. Finally, plant growth measurements revealed that the transgenic plants expressing the glycolate pathway in their chloroplasts have bigger leaf area as well as bigger rosette diameter compared to the control plants. Moreover, the total fresh and dry weight measurements showed that the total plant productivity was enhanced. Interestingly, most of the described effects were also observed in plants that only overexpressed a functional GDH. However, these effects were stronger in plants overexpressing all necessary elements of the glycolate pathway. Moreover, the phenotypical effects were much stronger when the bacterial GDH was compared to the plant GDH. Taken together, it can be concluded that expression of the novel pathway in C3 plant chloroplast does not only result in a reduction of photorespiration but it also enhances plant growth

A glycolate dehydrogenase in the mitochondria of Arabidopsis thaliana

The fixation of molecular O2 by the oxygenase activity of Rubisco leads to the formation of phosphoglycolate in the chloroplast that is further metabolized in the process of photorespiration. The initial step of this pathway is the oxidation of glycolate to glyoxylate. Whereas in higher plants this reaction takes place in peroxisomes and is dependent on oxygen as a co-factor, most algae oxidize glycolate in the mitochondria using organic co-factors. The identification and characterization of a novel glycolate dehydrogenase in Arabidopsis thaliana is reported here. The enzyme is dependent on organic co-factors and resembles algal glycolate dehydrogenases in its enzymatic properties. Mutants of E. coli incapable of glycolate oxidation can be complemented by overexpression of the Arabidopsis open reading frame. The corresponding RNA accumulates preferentially in illuminated leaves, but was also found in other tissues investigated. A fusion of the N-terminal part of the Arabidopsis glycolate dehydrogenase to red fluorescent protein accumulates in mitochondria when overexpressed in the homologous system. Based on these results it is proposed that the basic photorespiratory system of algae is conserved in higher plants

St. John's Daily Star, 1920-02-17

The St. John's Daily Star was published daily except Sunday between 17 April 1915 - 23 July 1921