Žurnal èvolûcionnoj biohimii i fiziologii

Understanding the molecular mechanisms of oocyte maturation, as well as early embryonic development, is of fundamental importance not only for embryology, but also for medical biology. However, the difficulties of experimental studies of this kind of problems in mammals, and especially in humans, are obvious. It is also well known that many key processes and mechanisms of oogenesis — early embryogenesis are highly evolutionarily conserved. They can be traced from the level of the most studied model invertebrates, such as Drosophila D. melanogaster and roundworm C. elegans, to mammals and humans. In this review, using these model invertebrates as an example, in comparison with model vertebrates, we will discuss the conservatism of such key processes and mechanisms as: (1) Transport/localization of mRNA by molecular motors; (2) Calcium wave; (3) Transport/localization of molecules by cytoplasmic streaming; (4) Segregation of determinant molecules by PAR protein networks; (5) Segregation of determinant molecules by actin filaments and myosins. The most general problem in this area is how cytoskeletal structures and protein networks are organized and reorganized, and how they interact with calcium waves, cytoplasmic streaming, and active transport by molecular motors. It is important that these conserved processes interact with each other, and the modes and mechanisms of their interaction also tend to be conservative. Thus, the transport of developmental determinants by motors along the cytoskeleton is interconnected with virtually all other processes. It is also significant that these processes and mechanisms also tend to form conservative scenarios. Thus, the prototypical scenario calcium wave → reorganization of actin-myosin cytoskeleton → generation of cytoplasmic flows can be traced back to mammals and humans, and is easier to study in detail in models. Finally, many of the conserved components under consideration turn out to be involved in pathological processes, including oncology. Thus, genes and the factors of the PAR network encoded by them, key to the mechanisms of cellular polarization, are characterized as oncogenes/oncofactors for a number of model objects. Analysis of large-scale studies of the processes and mechanisms of early development of model organisms raises a number of general evolutionary questions, discussed in the conclusion of this review.

The aim of the work is to study the development of the nervous apparatus and muscle structures of the rat lung in the early stages of postnatal development. The objects of study were extramural and intramural parts of the lung (trachea, main bronchi and lobar parts of the lung, including the respiratory section) of Wistar rats aged from one to fourteen days. Nervous structures were studied using immunohistochemical markers: PGP 9.5 protein, tyrosine hydroxylase, synaptophysin. Sarcomeric actin was used to identify muscle cells. It was found that in newborn rats, the distribution density of cholinergic structures (parasympathetic ganglia, microganglia of the nerve plexuses and terminal synaptic networks) prevails over catecholaminergic (sympathetic neurons and bundles of postganglionic fibers). Ganglionic plexuses are located around the trachea and main bronchi. Changes in tissue innervation in the bronchial wall of the lung in the cranio-caudal direction were detected. High density of distribution of nerve plexuses is characteristic of the proximal sections. They are absent in the alveolar regions. Close relationships of the main terminal nerve plexus with muscle tissue cells of the bronchial wall of different calibers up to the bronchioles are shown. Low innervation of cellular elements in the lobules around the pulmonary sacs and the absence of nerve terminals in the interalveolar septa are noted. Using the reaction to the S100β protein, cellular elements morphologically similar to the glial cells of Cajal, without axons included in their cytoplasm, were revealed in these places. An important feature is noted: the presence of cardiomyocytes in the muscular wall of the main pulmonary veins of the mediastinum and the cranial section of the lung. In the alveolar parts of the lungs, the wall of the pulmonary vein consists of smooth myocytes and the sphincters formed by them. The issues of differences in the histological structure and innervation of the afferent, efferent and exchange arterial and venous vessels of the microcirculatory bed of the lung require further special study. The absence of broncho-associated lymphoid tissue, characteristic of sexually mature animals, in the studied material at early stages of development was noted. The synchronicity of the formation of interneuronal and neuromuscular synapses, which are important for regulating the onset of the respiratory process in animals, was established.

The effects of specific blockers (ω-conotoxin GVIA, ω-agatoxin IVA, nitrendipine, SNX-482, mibefradil) of N, P/Q, L, R, and T-type potential-dependent Ca²⁺ channels were studied by fluorescence confocal microscopy, as well as the glycogen synthase kinase-3 enzyme inhibitor GSK3 (1-azakenpaullone) on exo-endovesicular cycle processes in cholinergic neuromuscular synapses of somatic muscle of the earthworm Lumbricus terrestris. The mechanisms of the vesicular cycle involve Ca²⁺ ions entering the terminals through all types of potential-dependent Ca²⁺ channels of the presynaptic membrane. At the same time, N-, P/Q-, and L-type Ca²⁺ channels contribute most to endocytosis processes, whereas only N- and P/Q-type channels contribute to exocytosis. Dynamin-dependent endocytosis plays an essential role in recycling processes, and the recovery of vesicular pools in such synapses is predominantly facilitated by clathrin-dependent endocytosis. It can be considered that the basic mechanisms of vesicular cycle regulation in motor neuromuscular synapses are common to the entire phylogenetic tree of vertebrates and invertebrates, beginning with annelids. At the same time, the importance of individual regulatory elements of the vesicular secretion machinery in annelids has its own distinct specificity.