Vol 53, No 6 (2017)

Proteins of the macroglobulin family are thioether-containing glycoproteins that act as inhibitors of a wide range of hydrolases, transporters and regulators of cytokine, hormone, lipid and oligonucleotide synthesis. As ancient components of innate immunity, these proteins are involved in folding of endogenous proteins as well as recognition and presentation of exogenous antigens. Interaction of macroglobulins with transmembrane receptors triggers cascades of reactions that regulate energy metabolism, cell division and apoptosis, participate in reproduction and cancerogenesis. A broad spectrum of conformational and functional states of molecules, depending on the type of ligands, and an appropriate set of implemented functions allow us to consider these proteins as key regulators of proteostasis. This review addresses the structure and function of macroglobulin proteins during evolution of organisms staying at different phylogenetic levels.

Using an indirect solid-phase immunoassay (ELISA test), cytochrome P-450, serotoninmodulated anticonsolidation protein (SMAP) and 70-kDa heat shock protein (HSP70) levels were analyzed in the brain and liver of the common carp Cyprinus carpio L. and golden carp Carassius auratus caught in reservoirs of the Arpachay river (clean zone) and Araks river (polluted zone) in Nakhchivan Autonomous Republic of Azerbaijan. Upregulation of cytochrome P-450 (p < 0.05) and SMAP (p < 0.01) in the common carp brain and downregulation of cytochrome P-450 (p < 0.05) and HSP70 (p < 0.05) in the golden carp liver were detected in fish caught in the Araks river reservoir as compared to levels of the same substances in fish from the Arpachay river reservoir. It is concluded that the brain plays a regulatory role in adaptation of animals to adverse environmental conditions and in protection of tissues from negative effects of pollutants.

A comparative immunological survey of cytotoxic properties of whole and cell-free haemolymph (plasma) was performed on four species of marine molluscs. Diverse target cells were used: auto- and heterologous mollusc haemocytes, starfish Asterias rubens coelomocytes, trematode Himasthla elongata rediae, and human erythrocytes. While all the four mollusc species were found to contain cytotoxic factors in their plasma, functional features of these molecules in bivalve and gastropod species are essentially different. Cell-free haemolymph of two clams, Mya arenaria and Mytilus edulis, contains pre-synthetized cytolytic complexes capable of immediate and generalized activation, leading to destruction of a broad range of target cells. On the contrary, two gastropod species, Buccinum undatum and Littorina littorea, possess haemolytic factors which display high specificity of recognition of receptor molecules on the target cells and slow cytolytic reaction. Overall, molecular strategies of cytolytic cascade activation in Bivalvia and Gastropoda can be described as low- and highly selective, respectively.

Hydrogen peroxide at a concentration of 100 μM was found to exert a pronounced modulatory effect on motor (R/L cells in B1–B4 clusters) and modulatory (R/L cerebral giant cells) neurons in the feeding neural network of the mollusc Lymnaea stagnalis as manifested in changes in the firing rate, membrane potential level and spike amplitude in these cells. The observed effects were reversible, transient, and reached their peak values in 1 min since application of the preparation. Injection of hydrogen peroxide into the cavity of the cephalopedal sinus resulted in no statistically significant changes in the parameters of mollusc feeding behavior. Hydrogen peroxide is assumed to act as a rapid neuromodulator towards neurons of the central feeding rhythm generator in Lymnaea stagnalis.

We investigated structural changes in the Wistar rat hippocampal CA1 field and fascia dentate during the pubertal period (on P60) after perinatal hypoxic exposure as well as the distribution of GAD67-expressing neurons in these structures. It was established that in the granular layer of the fascia dentata and in the CA1 field acute perinatal hypoxia leads to irreversible homotypic abnormalities as expressed in the reduced number of neurons and their rows as well as injury of a considerable portion of cells, which exhibit the signs of chromatolysis and vacuolization of the cytoplasm. Both in experimental and control animals, GAD67-expressing neurons in the fascia dentata are scattered diffusely and share approximately the same size of their populations. In the CA1 field, immunoreactive neurons lie in the lower rows of the pyramidal layer, while neurons in the upper layers exhibit no immunolabeling and have less synaptic structures in experimental animals than in control. We suggest that neurons in the hippocampal structures are involved in the regulation of functions and formation of prenatal pathology.