Том 49, № 6 (2018)

Functional interaction of the gastrointestinal tract (GI) and the central nervous system (CNS) is due to various relationships, which includes autonomic and enteral nervous systems as well as the immune and neuroendocrine systems. The microbiota of the macroorganism plays the central role in this interaction. Microbiota produces hundreds of biologically active substances that have a neurochemical effects through neuroendocrine, immune, and metabolic pathways. The microbiota also synthesizes and releases products (neurotoxins, neurotransmitters, lipopolysaccharides, amyloids, etc.) that can negatively affect the neurochemistry of the CNS, stimulating the development of amyloidosis, synucleinopathies, and tauopathies, thereby promoting the development and/or progression of neurodegenerative diseases. Under the influence of external and internal factors, human microbiota can be changed and the symbionts/pathogens ratio is also changed. The permeability of intestinal and blood-brain barrier varies. Metabolites produced by the altered microflora are able to enter the bloodstream and possibly into the CNS, thereby disrupting its functioning. Infections can play a significant role and even act as a cofactor in the induction of neurodegenerative diseases. Disturbance of the functions of the GI can precede long before the neurodegenerative processes. Early diagnosis, detection, monitoring, and treatment of negative gastrointestinal symptoms, including normalization of the microbiota, can lead to a significant improvement in the quality of life of patients with neurodegenerative diseases.

Agnathans, the most ancient of the extant vertebrates, evoke steadily increasing interest as the object of research on the basic processes of vertebrate ontogeny. Lampreys have been more accessible to researchers than myxines (hagfish), representatives of the other class of jawless vertebrates, for more than 100 years. Studies on the functional and evolutionary aspects of early ontogeny in lamprey at the molecular level became possible in the past two decades. Studies on the distinctive features of lampreys as the ancient representatives of vertebrates and comparison to gnathostomes, the more modern vertebrates, are of great interest. Molecular studies of lampreys can provide insight into the evolutionary mechanisms for the emergence and development of individual unique structures of vertebrates. The appearance of the telencephalon, which was first detected in lampreys, was one of the most important aromorphoses of vertebrates. Development and advancement of the telencephalon in the course of evolution enabled the implementation of higher forms of nervous activity in vertebrates, including humans. Research on the molecular mechanisms of basic ontogenetic events, such as early embryonic differentiation and neural induction, in the lamprey and other vertebrates is also important. Studies on the well-developed regeneration capacity of lampreys, in turn, give hope for at least partial use of the knowledge gained in future medical practice. This article is a review of recent data on the molecular aspects of the early development of the telencephalon, early embryonic differentiation, and regeneration of lampreys.

The technology of creating genetically modified animals (placental mammals) by microinjection into the pronucleus of a fertilized egg suggests, as one of the key stages, the transplantation of early embryos into female recipients. However, there is a wide range of opinions among researchers about the optimal number of embryos to be transferred to the female recipient. Thus, data on transplantation of 20–60 mouse embryos and from 2 to 6 goat embryos to one recipient are given in the methodological literature and experimental articles devoted to the method of creating genetically modified animals. Thus, the standard recommendation is the transfer of a much larger number of embryos than that which develops in animals of both species in physiological pregnancy. At the same time, technology of transplantation of bovine embryos (cattle) involves the transfer of one embryo, which is the physiological norm for this species of animals. Clinical protocols of assisted reproductive technologies for the transplantation of human embryos also recommend the transfer of one embryo, because transferring the number of embryos greater than in physiological pregnancy leads to increased risks. In our work, we analyze the results of experiments on obtaining genetically modified mice and goats and provide data indicating the need to revise the standard recommendations on the number of transferred embryos downward. We believe that the number of transferred embryos should not exceed the number of embryos characteristic for physiological pregnancy. Excess of the number of transplanted embryos leads to a pathological course of pregnancy and a significant decrease in overall performance.

Lately, the growing body of quantitative data has provided evidence of the importance of mechanical forces in embryogenesis. The study of spatial and temporal distribution of mechanical tension in the course of embryogenesis is one of the most important problems of modern developmental biology. Development of genetically encoded fluorescent mechanosensors allowed their application in an intravital study of mechanical tension in developing embryos via noninvasive techniques. The possibility of applying fluorescent mechanosensors based on vinculin and C-cadherin to visualize mechanical tension in tissues of Gallus and Xenopus embryos was studied. The methods to express and detect these proteins, as well as process the resulting images, were elaborated. The best results were obtained using Xenopus embryos and the vinculin-based mechanosensor.

In vitro cultivation of embryogenic cultures of Siberian larch on AI medium supplemented with different concentrations of antimicrobial peptides of two Trichoderma species, T. citrinoviride (strain TYVI 4/11) and T. viride (strain 346), has been performed to achieve a direct antimicrobial effect and initiate the mechanisms of induced resistance (regulatory function of embryogenic cultures) as well as to study the morphogenesis and growth activity of regenerant plants. The experiment was arranged using four cell lines, CL4, CL5, CL6, and CL12, differing in their embryogenic activity. The effect of treatment of cell cultures with Trichoderma peptides was manifested via significant growth stimulation of proliferating embryogenic cell lines, root growth stimulation, and formation of callus excrescences on regenerant plants. No difference between the treated and untreated variants was observed in seedlings. Conceivably, such peptide treatment may provide an increased immunity of soil-grown seedlings in forest nurseries. Study of the effect of biocontrol strains’ use in a plantation reforestation to stimulate the growth and development of calluses and embryos and to obtain disease-resistant regenerant plants of conifer species will provide the development of a clonal silviculture, a new trend that recently appeared abroad (Park 2002, 2014).

Individual growth of 15 great ramshorn snail Planorbarius corneus individuals was studied in aquaculture at 20°С starting from 2 weeks after hatching until the death of the animals. It was demonstrated that the weight of mollusks increases throughout the study period by an S-type curve. The linear growth (shell diameter) follows a parabolic (convex) curve. Both weight and linear growth on a specified age range is well approximated by the Bertalanffy equation, while the interdependence between the shell weight and diameter by an allometric equation. The value of Bertalanffy equation coefficients is different in different individuals. The mean values of the growth constants in these equations for the weight and linear growth do not differ. Their value is 0.041 ± 0.004 weeks^–1. The species lifespan, which is determined by a product of the growth constant into maximal lifespan, is ≈4.5.

The expression of Toll-like receptors TLR2 and TLR4 in the human retina during early prenatal development is shown for the first time. It was found that the development and differentiation of the retina is accompanied by specific spatial changes in the location of these receptors. TLR2 and TLR4 expression was detected in both neuroblastic retinal layers in gestation week 9. At subsequent developmental stages, the immunohistochemical staining for TLR2 and TLR4 gradually shifted towards the inner and outer plexiform layers of the retina and the nerve fiber layer. Our results suggest a possible involvement of these receptors in the regulation of neurogenesis and axonogenesis and the formation of synaptic connections between neurons and axons. The presence of TLR receptors in the endothelial cells forming retinal vessel walls does not exclude their role in the blood–retina barrier in pathogen infection.

The Agr (anterior gradient) group proteins belong to the family of proteins with a noncanonical thioredoxin motif and are involved in the regulation of various processes: embryonic development, regeneration, and oncogenesis. Normally, the human Agr2 gene is predominantly expressed in the secreting cells of mucin-producing organs. However, Agr2 is associated with active metastasis during the development of some types of malignant tumors. The molecular mechanism of its functioning is poorly understood. The model of Xenopus laevis embryos is one of the most convenient and available basic models for the proper study of various molecular mechanisms and signaling cascades of proteins. Previously, only the expression activity of the Agr genes was studied in this model; in particular, active expression of the Agr2 gene was demonstrated in the early stages of embryonic development and during tadpole regeneration of the tail and hindlimbs in Xenopus laevis. To begin the study on the molecular mechanism of the Agr2 protein functioning, it is necessary to obtain Agr2 specific antibodies and to test their effectiveness, which was the main goal of this work. The obtained purified antibodies were tested by the immunohistochemical method; as a result, the distribution pattern of the Agr2 protein during early development of the embryos and in regenerating tails of the tadpoles of Xenopus laevis, completely coinciding with the expression pattern of this gene, was first obtained.