DISCUSSIONS Thymic Involution in Ontogenesis: Role in Aging Program

Despite the important role of the thymus as the central organ of the immune system, aging is accompanied by thymic involution in most mammals In addition to physiological conditions that change throughout life and control age-related thymus development, random events can cause thymic involution as well as reversible temporal hypoplasia or hyperplasia of the thymus. Rapid reduction of thymic cellularity takes place in young patients who have experienced trauma, chemotherapy, and other forms of stress. Mechanisms that determine the process of involution appear to depend on factors inherent in thymic tissue, such as the local production of cytokines and chemoattractants that promote mobilization, growth, and differentiation of T-cells predecessors in the thymus and on external factors, such as the levels of endocrine hormones and mediators released by intrathymic neurons of the autonomic nervous system Abstract-In most mammals, involution of the thymus occurs with aging. In this issue of Biochemistry (Moscow) devoted to phenoptosis, A. V. Khalyavkin considered involution of a thymus as an example of the program of development and further -of proliferation control and prevention of tumor growth. However, in animals devoid of a thymus (e.g. naked mice), stimulation of carcinogenesis, but not its prevention was observed. In this report, we focus on the involution of the thymus as a manifestation of the aging program (slow phenoptosis). We also consider methods of reversal/arrest of this program at different levels of organization of life (cell, tissue, and organism) including surgical manipulations, hormonal effects, genetic techniques, as well as the use of conventional and mitochondria-targeted antioxidants. We conclude that programmed aging (at least on the model of age-dependent thymic atrophy) can be inhibited

Development of blast-resistant rice varieties based on application of DNA technologies

Diseases of agricultural crops are the main reason for decreased yield and quality of product. Blast (causative agent: Pyricularia oryzae Cav.) is the most harmful disease on rice fields. Economic damage caused by the pathogen is significant in all areas of the world’s rice cultivation. The most effective, economically justified and environmentally friendly strategy for combating it is development of resistant varieties. The application of DNA markers linked to loci of resistance to blast is relevant in this area. This makes it possible to significantly shorten the breeding process and promptly develop disease-resistant rice forms. In this regard, the aim of the work was to develop source material for breeding as well as highly productive rice varieties and lines with genes of resistance to blast based on the use of molecular marking method. To achieve this goal, we have launched a program since 2007 aimed at introduction of the blast resistance Pi-ta gene, effective for the south of Russia, into the domestic rice cultivar Flagman. After a number of recurrent crosses, the breeding material was obtained, which was studied for economically valuable traits in breeding nurseries. As a result of evaluation and rigorous discarding as well as according to the results of a phytopathological test for blast resistance, several lines were identified that have high indicators of milled rice quality, resistance to blast, yield and economically valuable traits. Rice accession KP-171-14 with the Pi-ta gene, adapted to growing conditions in the south of Russia, resistant to the Krasnodar population of P. oryzae, and having high yield and grain quality, in 2017 was submitted for State Variety Trials (SVT) under the name Alyans. Accessions KP-30 and KP-23 are tested for economically valuable traits and disease resistance in competitive variety trials. The best accession will be submitted to SVT. The introduction and cultivation of such varieties will reduce the use of chemical protection products, obtain environmentally friendly agricultural products and avoid contamination of grain ecosystem

Six Functions of Respiration: Isn’t It Time to Take Control over ROS Production in Mitochondria, and Aging Along with It?

Cellular respiration is associated with at least six distinct but intertwined biological functions. (1) biosynthesis of ATP from ADP and inorganic phosphate, (2) consumption of respiratory substrates, (3) support of membrane transport, (4) conversion of respiratory energy to heat, (5) removal of oxygen to prevent oxidative damage, and (6) generation of reactive oxygen species (ROS) as signaling molecules. Here we focus on function #6, which helps the organism control its mitochondria. The ROS bursts typically occur when the mitochondrial membrane potential (MMP) becomes too high, e.g., due to mitochondrial malfunction, leading to cardiolipin (CL) oxidation. Depending on the intensity of CL damage, specific programs for the elimination of damaged mitochondria (mitophagy), whole cells (apoptosis), or organisms (phenoptosis) can be activated. In particular, we consider those mechanisms that suppress ROS generation by enabling ATP synthesis at low MMP levels. We discuss evidence that the mild depolarization mechanism of direct ATP/ADP exchange across mammalian inner and outer mitochondrial membranes weakens with age. We review recent data showing that by protecting CL from oxidation, mitochondria-targeted antioxidants decrease lethality in response to many potentially deadly shock insults. Thus, targeting ROS- and CL-dependent pathways may prevent acute mortality and, hopefully, slow aging