Том 6, № 6 (2016)

A half century of studying the neurogenesis of the adult brain has produced much evidence for an endogenous conversion of neural stem cells. Yet the idea receives increasing criticism, in addition to the many positive comments. Does neurogenesis proceed at a rate sufficiently high for its functional significance? Are new cells capable of integrating into proper brain regions in order to perform a reparative role? How long do new neurons persist in the integration sites, and how significant is their role in the neuronal circuit structure? An organizing function is hypothesized for endogenous adult brain neurogenesis on the basis of current information. One of the main arguments for the hypothesis is the multiplicity of key physiological processes functionally associated with the involvement of new neurons and glial cells: learning, memory, adaptive behavior, protective stress responses, reproductive function, changes in the state of mind, injuries, ischemic and neurodegenerative disorders, etc. The adjustable reprogramming of neuronal precursors and the reparative role of new cells are analyzed. The organizing role of neurogenesis is considered a justified complex process that is important for the function of the adult brain.

Mycobacterium tuberculosis (Mtb) is an intracellular pathogen that mainly affects alveolar macrophages. We have still no satisfactory vaccine against tuberculosis, and more than one-third of the global population are carriers of this pathogen. For the development of a vaccine that would induce not only humoral but, particularly, cell-mediated immunity, we must know all of the processes involved in the interaction between elements of the immune system and Mtb at all stages of the disease. This review considers the responses of immune system elements to various factors used by Mtb for cell invasion, survival, and reproduction.

Several molecular and genetic features of cells from Down syndrome patients are considered in comparison to those of healthy donors, as is the possibility of using these cells to study mechanisms of the transformation of normal cells to malignant ones, based on the study of the expression of the genes controlling these processes. The role of microRNAs in the regulation of gene activity is estimated. These investigations make it possible to detect the genes for a hereditary predisposition to oncogenesis. The application of antimutagens-anticancerogens provides a new approach to the prophylaxis of this and other human pathologies. In addition, the data on the hypersensitivity of Down syndrome cells to genotoxicants (radiation and others) and the possibility of correcting these disturbances with antimutagens are presented. A special section is devoted to specific changes in cells typical for Down syndrome and Alzheimer disease; the commonality of several elements of the pathogenesis of these diseases is emphasized. The research on Down syndrome cells in terms of an imbalance in the entire genome under this pathology opens new means for the prophylaxis and treatment of several human pathologies.

Only a few decades ago, symbiosis between insects and bacteria was considered a relatively rare phenomenon. The concept of symbiosis has changed in the past two decades due to the development of molecular-genetic methods. At the same time, a peculiar variant of symbiotic relationships, reproductive parasitism (i.e., modification of the host reproductive strategy by symbiotic bacteria) has been actively discussed by researchers. The intracytoplasmic bacterium Wolbachia pipientis is the most common reproductive symbiont of insects. The age of the symbiosis between the Wolbachia and insects is estimated to be 150 million years. The biological effects of the bacterium on different insect species vary from sporadic asymptomatic carriage to obligate symbiosis with many intermediate forms. Each of the millions of insect species infected with Wolbachia develops its own unique genetic mechanisms of the interaction with the bacterium. New events of infection of insect species with Wolbachia and its losses occur quite often, and not only in evolutionary time periods. The present review summarizes the current data on the genetic control of modification of the insect reproductive behavior caused by the Wolbachia and data on the effect of Wolbachia on the adaptation of infected insects. The paper also presents the data on the relatively poorly studied process of genetic recombination in representatives of the bacterial genus.