Oligomeric protein complexes of apolipoproteins stabilize the internal fluid environment of organism in redfins of the Tribolodon genus [Pisces; Cypriniformes, Cyprinidae].

One of the most important functions of plasma proteins in vertebrates is their participation in osmotic homeostasis in the organism. Modern concepts about plasma proteins and their capillary filtration are based on a model of large monomeric proteins that are able to penetrate the interstitial space. At the same time, it was revealed that a considerable amount of oligomeric complexes are present in the low-molecular-weight (LM) protein fraction in the extracellular fluids of fishes. The functions of these complexes are unknown. In the present study, we investigated the LM-fraction proteins in the plasma and interstitial fluid (IF) of redfins of the genus Tribolodon. This fish alternatively spends parts of its life cycle in saline and fresh waters. We identified the protein Wap65, serpins and apolipoproteins in this fraction. By combining the methods of 2D-E under native and denaturing conditions with MALDI, we demonstrated that only apolipoproteins formed complexes. We showed that serum apolipoproteins (АроА-I, Аро-14) were present in the form of homooligomeric complexes that were dissociated with the release of monomeric forms of proteins in the course of capillary filtration to IF. Dissociation of homooligomers is not directly correlated with the change in salinity but is correlated with seasonal dynamics. We found that there was a significant decrease in the total protein concentration in IF relative to plasma. Therefore, we suggested that dissociation of homooligomeric complexes from various apolipoproteins supports the isoosmoticity of extracellular fluids relative to capillary wall stabilization through a fluid medium in fish.

Analgetic effect of docosahexaenoic acid is mediated by modulating the microglia activity in the dorsal root ganglia in a rat model of neuropathic pain.

The analgetic activity of docosahexaenoic acid (DHA, 22:6 n-3) was studied using a chronic constriction injury (CCI) model in rats, and the dynamics of iba-1 (+) microglia/macrophages in the dorsal root ganglia (DRG) were characterized. DHA reduced the intensity and duration of neurogenic pain. The application of DHA led to an earlier stabilization of weight bearing in the incapacitance test and prevented the development of cold allodynia and degenerative changes in tissues of the denervated limb. DHA treatment significantly reduced satellite glia reaction and expression of the pro-apoptotic p53 protein in the DRG. Thus, DHA's anti-pain effect may be a result of the modulation of microglia/macrophages activity and the development of neuroprotective effects at the level of the dorsal root ganglia.

Proteases from the regenerating gut of the holothurian Eupentacta fraudatrix.

Four proteases with molecular masses of 132, 58, 53, and 47 kDa were detected in the digestive system of the holothurian Eupentacta fraudatrix. These proteases displayed the gelatinase activity and characteristics of zinc metalloproteinases. The 58 kDa protease had similar protease inhibitor sensitivity to that of mammalian matrix metalloproteinases. Zymographic assay revealed different lytic activities of all four proteases during intestine regeneration in the holothurian. The 132 kDa protease showed the highest activity at the first stage. During morphogenesis (stages 2-4 of regeneration), the highest activity was measured for the 53 and 58 kDa proteases. Inhibition of protease activity exerts a marked effect on regeneration, which was dependent on the time when 1,10-phenanthroline injections commenced. When metalloproteinases were inhibited at the second stage of regeneration, the restoration rates were decreased. However, such an effect proved to be reversible, and when inhibition ceased, the previous rate of regeneration was recovered. When protease activity is inhibited at the first stage, regeneration is completely abolished, and the animals die, suggesting that early activation of the proteases is crucial for triggering the regenerative process in holothurians. The role of the detected proteases in the regeneration processes of holothurians is discussed.

Three cone opsin genes determine the properties of the visual spectra in the Japanese anchovy, Engraulis japonicus (Engraulidae, Teleostei).

A complement of cone visual pigments was identified in the Japanese anchovy Engraulis japonicus, one of the engraulid fish species that has a retina specialized for polarization and color vision. The nature of the chromophore bound to opsin proteins was investigated using high performance liquid chromatography. The opsin genes were then cloned and sequenced, and the absorption spectra of different types of cones were obtained by microspectrophotometry. Two green (EJ-RH2-1, EJ-RH2-2) and one red (EJ-LWS) cone opsin genes were identified and are presumably related to the vitamin A1-based visual pigments (i.e. rhodopsins) with λmax values of 492, 474 and 512 nm, respectively. The long and short cones from the ventro-temporal retinal zone consisted of a pure population of RH2 class gene-based pigments (λmax=492 nm). The long and short cones from other retinal areas and the lateral components of the triple cones possessed a mixture of RH2 and LWS class gene-based pigments that exhibited a λmax of ~502 nm. The central component of the triple cones contained only RH2 class gene-based pigments (λmax=474 nm). Thus, E. japonicus possesses a middle-wave range of spectral sensitivity and acquires different color vision systems in distinct visual fields.

Changes in the nitric oxide system in the shore crab Hemigrapsus sanguineus (Crustacea, Decapoda) CNS induced by a nociceptive stimulus.

Using NADPH-diaphorase (NADPH-d) histochemistry, inducible nitric oxide synthase (iNOS)-immunohistochemistry and immunoblotting, we characterized the nitric oxide (NO)-producing neurons in the brain and thoracic ganglion of a shore crab subjected to a nociceptive chemical stimulus. Formalin injection into the cheliped evoked specific nociceptive behavior and neurochemical responses in the brain and thoracic ganglion of experimental animals. Within 5-10 min of injury, the NADPH-d activity increased mainly in the neuropils of the olfactory lobes and the lateral antenna I neuropil on the side of injury. Later, the noxious-induced expression of NADPH-d and iNOS was detected in neurons of the brain, as well as in segmental motoneurons and interneurons of the thoracic ganglion. Western blotting analysis showed that an iNOS antiserum recognized a band at 120 kDa, in agreement with the expected molecular mass of the protein. The increase in nitrergic activity induced by nociceptive stimulation suggests that the NO signaling system may modulate nociceptive behavior in crabs.