Molecular genetic and karyological analysis of antlered sculpins of <Emphasis Type="Italic">Enophrys diceraus</Emphasis> group (Cottidae)

Molecular genetic and karyological analyses of antlered sculpin, Enophrys diceraus, from the Sea of Japan and the Sea of Okhotsk were carried out. The karyotype of this species was studied for the first time. On the basis of karyological analysis, it was established that E. diceraus from the Sea of Japan and the Sea of Okhotsk was polymorphic in terms of the number of chromosomes and their morphology (2n = 36, 35, and 37, NF = 40). It was suggested that the karyotype with 35 chromosomes could have been produced as a result of Robertsonian translocation; the karyotype with 37 chromosomes could have been produced by crossing of individuals with different number of chromosomes. On the basis of the molecular genetic analysis of the mitochondrial COI and 16S rRNA genes, considerable differences between E. diceraus from the Sea of Japan and the Sea of Okhotsk corresponding to the level of interspecies genetic variability were established. It is concluded that E. diceraus from the Sea of Japan belongs to another species, most likely, E. namiyei.     

Biological activity of hemoprotein nitrosyl complexes

Chemical and biological functions of hemoprotein nitrosyl complexes as well as their photolysis products are discussed in this review. Chemical properties of nitric oxide are discussed, and major chemical reactions such as interaction with thiols, free radicals, and transition metals are considered. Specific attention is paid to the generation of hemoprotein nitrosyl complexes. The mechanisms of nitric oxide reactions with hemoglobin and cytochrome c and physicochemical properties of their nitrosyl complexes are discussed. A review of photochemical reactions of nitrosyl complexes with various ligands is given. Finally, we observe physiological effects of visible radiation on hemoprotein nitrosyl complexes: smooth muscle relaxation and reactivation of mitochondrial respiration.     

Nonglutamate pore residues in ion selection and conduction in voltage-gated Ca(2+) channels

High-affinity, intrapore binding of Ca(2+) over competing ions is the essential feature in the ion selectivity mechanism of voltage-gated Ca(2+) channels. At the same time, several million Ca(2+) ions can travel each second through the pore of a single open Ca(2+) channel. How such high Ca(2+) flux is achieved in the face of tight Ca(2+) binding is a current area of inquiry, particularly from a structural point of view. The ion selectivity locus comprises four glutamate residues within the channel's pore. These glutamates make unequal contributions to Ca(2+) binding, underscoring a role for neighboring residues in pore function. By comparing two Ca(2+) channels (the L-type alpha(1C), and the non-L-type alpha(1A)) that differ in their pore properties but only differ at a single amino acid position near the selectivity locus, we have identified the amino-terminal neighbor of the glutamate residue in motif III as a determinant of pore function. This position is more important in the function of alpha(1C) channels than in alpha(1A) channels. For a systematic series of mutations at this pore position in alpha(1C), both unitary Ba(2+) conductance and Cd(2+) block of Ba(2+) current varied with residue volume. Pore mutations designed to make alpha(1C) more like alpha(1A) and vice versa revealed that relative selectivity for Ba(2+) over K(+) depended almost solely on pore sequence and not channel type. Analysis of thermodynamic mutant cycles indicates that the motif III neighbor normally interacts in a cooperative fashion with the locus, molding the functional behavior of the pore.     

Gramicidin derivatives as membrane-based pH sensors.

Ion channels provide a means for sensitive pH measurement at membrane interfaces. Detailed knowledge of the structure and function of gramicidin channels permits the engineering of pH-sensitive derivatives. Two derivatives, gramicidin-ethylenediamine and gramicidin-histamine, are shown to exhibit pH-dependent single-channel behaviour over the pH ranges 9-11 and 6.5-8.5, respectively. Thermal isomerization of a carbamate group at the entrance of the channels leads to a pattern of steps in single-channel recordings. The size of the steps depends on the time-averaged degree of protonation of the appended group (ethylenediamine or histamine). Measurement of the size of the steps thus permits single-molecule pH sensing under symmetrical pH conditions or in the presence of a pH gradient.     

Distribution of cytoplasmic ferroproteins and iron in human kidney tumors

Using immuno- and histochemical techniques, it has been shown that the primary tumoural node in kidney cancer is a locus with an extraordinarily high concentration of cytoplasmic ferroproteins and ferrum (Fe3+). Fe3+ is located in the cytoplasm of nephrothelium of tumour-affected kidney tubules, intensively incrustates the cell cytoplasm in the primary tumoural node and is revealed in separate nuclei of the primary node cells. Possible consequences of high local ferrum concentration in cells is discussed. It is suggested that ferroprotein accumulations and the peculiarities of their distribution in kidney tumours result from the disturbances in ferrum metabolism that antecede the onset of kidney tumours.     

Hydroacoustic characteristics of mass fishes of the Ob-Irtysh Basin

Hydroacoustic characteristics of mass fish species of the Ob-Irtysh Basin are investigated for elaboration of instrumental methods of fish identification by the results of hydroacoustic surveys. Linear-logarithmic regression equations of average values of the acoustic “target strength” are obtained, depending on the body length and weight of located objects. Instant values of the form of the echo signal envelope of amplitudes of echo signals from fish are analyzed. The numerical values of their statistical parameters are obtained. The characteristics of the backscattering from different species may be used for the solution of practical tasks of identification of fish and estimation of bioresources on inland water bodies.     

Irregularities of the bottom and fish aggregations on a stretch of the Irtysh

An original method for estimation of the effect of bottom irregularities on density of fish aggregations is elaborated. Calculation of the investigated relationship is based on material of surveys collected by an AsCor hydroacoustic complex and is made by means of special software. With reference to a deep-water stretch of the Irtysh channel, the quantitative parameters of the relationship between densities of fish aggregations and the index of bottom irregularity are revealed. The diagram of the relationship between bottom irregularities and density of fish aggregations, the three-dimensional model of bottom relief of the investigated water area, and echograms of fish aggregations on various stretches of the river are presented.