Elena Garnik - Academia.edu (original) (raw)

Papers by Elena Garnik

Siberian journal of life sciences and agriculture, Dec 25, 2022

Электрон-транспортная цепь митохондрий, в частности дыхательный комплекс I, является одним из осн... more Электрон-транспортная цепь митохондрий, в частности дыхательный комплекс I, является одним из основных источников активных форм кислорода (АФК) в клетках живых организмов. Подавление работы комплекса I в клетках человека посредством химического ингибирования или мутаций, нарушающих функциональность этого комплекса, ведет к существенному возрастанию содержания АФК. Для растений также известны мутанты по субъединицам комплекса I, однако до настоящего времени не ясно, приводит ли подавление активности этого комплекса к возрастанию уровня АФК и развитию окислительного стресса. Цель. Исследовать уровень супероксида, перекиси водорода и чувствительность к прооксидантам в клетках линии арабидопсиса ndufs4 с инактивированным посредством инсерционного мутагенеза комплексом I. Материалы и методы. Использовали суспензионную культуру клеток арабидопсиса дикого типа и инсерционного мутанта по субъединице комплекса I NDUFS4. Содержание перекиси водорода в клетках оценивали по флуоресценции дихлорофлуоресцеина. Уровень супероксидного радикала определяли путем окрашивания клеток нитросиним тетразолием.

Journal of Experimental Botany, 2017

Doklady Biochemistry and Biophysics, 2014

92 Light is the key factor in the regulation of plant cell functioning, which affects the process... more 92 Light is the key factor in the regulation of plant cell functioning, which affects the processes associated not only with chloroplasts but also with other organelles, including mitochondria. The aim of this work was to compare the level of expression of nuclear and mito� chondrial genes encoding subunits of various com� plexes in the respiratory chain in Arabidopsis leaves in the light and in the dark. The result showed that some of the studied nuclear genes encoding primarily sub� units of respiratory complexes V and I are expressed in the plants at higher levels in the light. The level of tran� scripts of the majority of mitochondrial genes encod� ing the components of the same respiratory complexes is not changed or increased under conditions of dark incubation compared to the plants exposed to light. These data are suggestive of a coordinated regulation of the expression of subunits of certain respiratory chain complexes encoded by the nucleus in the light.

Doklady Biochemistry and Biophysics, 2013

Russian Journal of Plant Physiology, 2010

The mutant line of Arabidopsis thaliana obtained by insertion mutagenesis of fro gene (at5g67590)... more The mutant line of Arabidopsis thaliana obtained by insertion mutagenesis of fro gene (at5g67590) encoding the 18 kD Fe-S subunit of mitochondrial respiratory chain complex I was characterized. The homozygous plants carrying the insert were selected by PCR genotyping. The absence in these plants of tran scripts corresponding in size to the fro gene was confirmed by gene expression analysis. The homozygous plants obtained were characterized by several phenotypic features, such as late seed germination, retarded growth and development, the increased number and deep green color of leaves. At variance with earlier data obtained for splicing defective mutants of the Arabidopsis fro gene, the plants obtained in this study did not exhibit a lower resistance to abiotic stresses. Despite complete inactivation of the fro gene, the mutant plants were similar to the wild type plants in terms of biomass growth and productivity. It is concluded that regula tory systems for gene expression in mutant Arabidopsis plants with impaired respiratory complex I are able to largely compensate for the respiratory deficiency at the phenotypic level.

Biologia plantarum, 2012

Alternative oxidase (AOX) transfers electrons from ubiquinone to oxygen in the respiratory chain ... more Alternative oxidase (AOX) transfers electrons from ubiquinone to oxygen in the respiratory chain of plant mitochondria. It is widely accepted that AOX functions as a mechanism decreasing the formation of reactive oxygen species (ROS) produced during respiratory electron transport. However, there are no experimental data to provide unambiguous proof of this hypothesis. We have studied growth characteristics, ROS content, and stress sensitivity in Arabidopsis transgenic lines with reduced or increased levels of AOX. We demonstrated that AOX-deficient plants grown in soil had an extended reproductive phase. Changes in AOX activity did not affect ROS content or stress sensitivity in the whole plants. However in the suspension culture, cells overexpressing AOX had significantly lower ROS content, whereas the AOX-deficient cells had higher ROS content compared to the wild-type (WT) cells. Prooxidant treatment led to the increase in ROS content and to the reduction of viability more in the cells overexpressing AOX than in WT and AOX-deficient cells. Thus, we demonstrated that differences in the metabolism of whole plants and cultured cells might affect AOX functioning.

Biochemistry (Moscow), 2009

Expression of the gdh2 gene encoding the α subunit of mitochondrial glutamate dehydrogenase depen... more Expression of the gdh2 gene encoding the α subunit of mitochondrial glutamate dehydrogenase depends on redox state of the mitochondrial electron transport chain. Treatment of Arabidopsis thaliana cell suspension with antimycin A, a respiratory chain complex III inhibitor, resulted in an increase in gdh2 transcripts within 2 h. Inhibition of complex I by rotenone did not influence the transcript level, but treatment with potassium cyanide, a complex IV inhibitor, also increased the transcript content. Thus, gdh2 gene expression obviously responds to changes in the respiratory chain segment localized between complexes I and III. Lack of activation of gene expression after treatment of a cell suspension with hydrogen per oxide and the prooxidant paraquat and results of experiments with antioxidants suggest that gdh2 gene expression is not associated with increased content of reactive oxygen species generated during inhibition of the electron transport chain. Protein phosphorylation by serine/threonine protein kinases is the essential step required for signal transduction into nucle us resulting in the induction of gdh2 expression.

Journal of Experimental Botany, 2016

In a number of dicotyledonous plants, including Arabidopsis, the transcription of organellar gene... more In a number of dicotyledonous plants, including Arabidopsis, the transcription of organellar genes is performed by three nuclear-encoded RNA polymerases, RPOTm, RPOTmp, and RPOTp. RPOTmp is a protein with a dual targeting, which is presumably involved in the control of gene expression in both mitochondria and chloroplasts. A previous study of the Arabidopsis insertion rpotmp mutant showed that it has retarded growth and development, altered leaf morphology, changed expression of mitochondrial and probably some chloroplast genes, and decreased activities of the mitochondrial respiratory complexes. To date, there is no clear evidence as to which of these disorders are associated with a lack of RPOTmp in each of the two organelles. The aim of this study was to elucidate the role that this RNA polymerase specifically plays in mitochondria and chloroplasts. Two sets of Arabidopsis transgenic lines with complementation of RPOTmp function in either mitochondria or chloroplasts were obtained. It was found that the recovery of RPOTmp RNA polymerase activity in chloroplasts, although restoring the transcription from the RPOTmp-specific PC promoter, did not lead to compensation of the mutant growth defects. In contrast, the rpotmp plants expressing RPOTmp with mitochondrial targeting restored the level of mitochondrial transcripts and exhibit a phenotype resembling that of the wild-type plants. We conclude that despite its localization in two cell compartments, Arabidopsis RPOTmp plays an important role in mitochondria, but not in chloroplasts.

Russian Journal of Plant Physiology, 2006