Larvae of related Diptera species from thermally contrasting habitats exhibit continuous up-regulation of heat shock proteins and high thermotolerance

A population of Stratiomys japonica, a species belonging to the family Stratiomyidae (Diptera), common name ‘soldier flies’, occurs in a hot volcanic spring, which is apparently among the most inhospitable environments for animals because of chemical and thermal conditions. Larvae of this species, which naturally often experience temperatures more than 40 °C, have constitutively high concentrations of the normally inducible heat-shock protein Hsp70, but very low level of corresponding mRNA. Larvae of three other species of the same family, Stratiomys singularior, Nemotelus bipunctatus and Oxycera pardalina, are confined to different type semi-aquatic habitats with contrasting thermal regime. However, all of them shared the same pattern of Hsp70 expression. Interestingly, heat-shock treatment of S. japonica larvae activates heat-shock factor and significantly induces Hsp70 synthesis, whereas larvae of O. pardalina, a species from constant cold environment, produce significantly less Hsp70 in response to heat shock. Adults of the four species also exhibit lower, but detectable levels of Hsp70 without heat shock. Larvae of all species studied have very high tolerance to temperature stress in comparison with other Diptera species investigated, probably representing an inherent adaptive feature of all Stratiomyidae enabling successful colonization of highly variable and extreme habitats.     

Experimental evidence for simultaneous existence of two dominantas in the central nervous system

For the first time a possibility of simultaneous existence of two dominants was demonstrated: the polarization in the cortical representation of the forelimb and the dominanta of hunger. The two foci of stable excitation were created at the subthreshold level. A sound stimulus simultaneously produced a movement of the forelimb and a gulp. Manifestation of the two dominantas could be observed over the course of the experiment (about 1 h).     

Comparison of the biological effects of tritium oxide and gamma radiation based on changes in the mass of the rat thymus gland

RBE of tritium oxide (cumulative doses from 0.33 to 14.7 Gy), in comparison with gamma-radiation, amounted to 2-3 as estimated by the thymus mass. As determined by the rate of injury and repair, the RBE values decreased from 4 to 1.4 with dose increasing, and from 6.5 to 1.3, by the periods of half-decrease and half-recovery of the organ mass. The 2-3-fold variations in the RBE values for various parameters of the organ mass changes were registered at low doses, whereas within the range of median and high doses under study, the differences were insignificant.     

Multiple activation loop conformations and their regulatory properties in the insulin receptor's kinase domain

Low catalytic efficiency of protein kinases often results from intrasteric inhibition caused by the activation loop blocking the active site. In the insulin receptor's kinase domain, Asp-1161 and Tyr-1162 in the peptide substrate-like sequence of the unphosphorylated activation loop can interact with four invariant residues in the active site: Lys-1085, Asp-1132, Arg-1136, and Gln-1208. Contributions of these six residues to intrasteric inhibition were tested by mutagenesis, and the unphosphorylated kinase domains were characterized. The mutations Q1208S, K1085N, and Y1162F each relieved intrasteric inhibition, increasing catalytic efficiency but without changing the rate-limiting step of the reaction. The mutants R1136Q and D1132N were virtually inactive. Steric accessibility of the active site was ranked by relative changes in iodide quenching of intrinsic fluorescence, and A-loop conformation was ranked by limited tryptic cleavage. Together these ranked the openness of the active site cleft as R1136Q approximately D1132N > or = D1161A > Y1162F approximately K1085N > Q1208S > or = wild-type. These findings demonstrate the importance of specific invariant residues for intrasteric inhibition and show that diverse activation loop conformations can produce similar steady-state kinetic properties. This suggests a broader range of regulatory properties for the activation loop than expected from a simple off-versus-on switch for kinase activation.     

Interactions between electrical activities of the sensomotor cortex and the hippocampus during 'animal hypnosis' in rabbits

The electrical activity of the left and right sensorimotor cortex and left and right dorsal hippocampus (CA3 fields) was recorded during "animal hypnosis" in rabbits. The "animal hypnosis" produced asymmetry in the spectral power of the hippocampal electrical activity due to an increase in the power of delta 1, delta 2, and theta 1 components in the left-hippocampus and decrease in the spectral power in the same ranges in the right-hippocampus. Hemispheric asymmetry in the electrical activity during the "animal hypnosis" was also expressed in the indices of coherence between the sensorimotor cortex and hippocampus. EEG coherence between the left sensorimotor cortex and left hippocampus in the delta 1, theta 1, and theta 2 ranges was higher than that between the right-side structures.     

Intercentral reticulo-cortical relations of brain electrical activity during "animal hypnosis" in rabbits

The electrical activity of the right and left sensorimotor and premotor cortical areas and right and left medulary reticular formation was recorded during "animal hypnosis" in rabbits. In this state, the spectral power of potentials (predominantly, in the delta-range) recorded from the left reticular formation was higher than that recorded from the right side. The value of the function of coherence between the right and left reticular recordings was decreased to 0.1-0.2 in the whole frequency range. The tight-side intrahemispheric coherence between the activities recorded from the sensorimotor cortex and reticular formation was higher than respective left-side values, whereas the coherent relations between the activities recorded from the reticular formation and premotor cortex were not changed (as compared to nonhypnotic state).     

Cortico-hippocampal relation of electrical activity during a motor polarization dominant in rabbits

By the method of spectral-coherent analysis, the intercentral relations were studied of the electrical activity of the sensorimotor and premotor cortices and of CAs field of the dorsal hippocampus of both hemispheres during the motor polarization dominant, created by the action of the direct current on the rabbits sensorimotor cortical area. The formation was shown of a new structure of the intercentral relations of electrical activity of the sensorimotor cortex and CA3 of the dorsal hippocampus. It should be noted that the dominant optimum and its inhibition are characterized by different interhippocampal relations: at the optimum a low range of the theta-rhythm is highly coherent while at the activation of "the non-dominant" hemisphere--a high range.