Somatic embryogenesis in Larix: the state of art and perspectives.

Clonal propagation of conifers using somatic embryogenesis is essential for the selection of tree species, and for the implementation of afforestation and reforestation. In combination with cryopreservation, somatic embryogenesis creates the basis for the development of economically valuable lines of clones and elite genotypes. The industrial use of such genetically verified clone lines in forestry can significantly increase forest productivity compared to any conventional methods for improving tree crops that are available. Larch is considered as one of the main conifer candidates for large-scale reforestation, not only due to the vastness of its habitat, but also due to the unique quality of its wood, rapid growth and high ecological plasticity. However, the vast majority of larch species are characterized by uneven yields and extremely low seed quality. In this regard, obtaining planting material for reforestation from larch seeds on seed plantations is not advisable, but can be successfully implemented in afforestation programs using somatic embryogenesis technologies. Research on the somatic embryogenesis of larch has been conducted for over 30 years, which allowed considerable experience in this field to be accumulated. To date, the conditions for the initiation and maintenance of embryogenic cultures, as well as for the formation and development of somatic embryos have been determined. Significant progress has been made in the study of both the factors affecting these processes and the molecular mechanisms that underlie the various stages of embryogenesis. Nevertheless, despite the successes achieved, knowledge available today on the somatic embryogenesis of representatives of the genus Larix is still not enough to develop technologies for producing valuable plant-breeding material in vitro. This review analyzes the current state of research on the problem of somatic embryogenesis of representatives of the genus Larix. Particular attention is paid to the choice of explants for somatic embryogenesis, the composition of the media for cultivation, the dependence of the potential of somatic embryogenesis on the duration of cultivation, and the genetic control of somatic embryogenesis.

Induction of Arabidopsis gdh2 gene expression during changes in redox state of the mitochondrial respiratory chain.

Expression of the gdh2 gene encoding the alpha-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 peroxide 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 nucleus resulting in the induction of gdh2 expression.

[Disruption of the electrolyte and microelement composition of gastric juice and bile in patients with chronic diseases of the hepatobiliary system]. / Narushenie élektrolitnogo i mikroélementonogo sostava zheludochnogo soka i zhelchi u bol'nykh khronicheskimi zabolevaniiami geptobiliarnoi sistemy.

A study is presented of 403 patients with chronic diseases of the stomach and biliary tract. It was established that these patients showed disorders of the electrolytic and micro-element composition of the gastric juice and bile depending on the functional state of the stomach and liver.

[The treatment of peptic ulcer]. / O lechenii iazvennoi bolezni.

Problems are discussed on the differential pathogenetic treatment of patients with duodenal ulcer. Variants are singled out of the course of ulcer disease depending on the prevalence of clinical symptoms. The characteristic features of these symptoms are described and the most rational and individualized therapeutic complexes for each of these clinical variants are evaluated.

[Training and practical summer work of 4th-year medical students]. / Podgotovka i provedenie letnei proizvodstvennoi praktiki u studentov IV kursa lechebnogo fakul'teta.

Practical work of the 4th-year medical students is aimed at strengthening the knowledge acquired by them at medical and theoretical chairs, further extension and improvement of practical skills, acquaintance with the organization of curative work, physicians' labour conditions at the regional and country level, principles of public health organization and antiepidemic activity.