[Osphradial chemosensory organ as a probable trigger of the cardiac system adaptive reaction to the effect of heavy metals in aquatic mollusks].

The responses of osphradium in the fresh-water mollusk Viviparus sp. and single osphradial neurons in the pond snail Lymnaea stagnalis to L-glutamine and L-asparagine as well as the changes in these responses under the effect of heavy metals (Cu, Cd) were recorded electrophysiologically. The functional connections of osphradium with the identified neurons of the central pattern generator of respiratory movements and cardiac activity as well as the modification of these connections under the effect of short-term application of HgCl2 solution on the snail's osphradium were investigated. The cardiac rhythm in the mollusk Littorina littorea under the effect of Cu ions was registered non-invasively in long-lasting experiments. The dose-dependent short-term effects of heavy metals changes after osphradium injury were revealed. The implication of osphradium in adaptive reactions of the cardiac system in aquatic mollusks to the environmental heavy metal pollution is suggested. The dependence of cardiac rhythm on the degree of accumulation of copper ions in the mollusk tissues was detected. The results obtained are essential for unraveling neural mechanisms and pathways allowing heavy metals to affect the functional state of hydrobionts, particularly, the cardiac activity frequency characteristics of which are widely used as informative biomarkers to assess physiological condition of aquatic invertebrates.

A multibiomarker approach to the assessment of pollution impacts in two Baltic Sea coastal areas in Sweden using caged mussels (Mytilus trossulus).

Blue mussels (Mytilus trossulus) were transplanted in cages for three months in two Swedish coastal areas in the Bothnian Sea (northern Baltic Sea) to investigate the interactions between analysed environmental chemicals and biological responses. A wide array of biological parameters (biomarkers) including antioxidant and biotransformation activity, geno-, cyto- and neurotoxic effects, phagocytosis, bioenergetic status and heart rate were measured to detect the possible effects of contaminants. Integrated Biomarker Response index and Principal Component Analysis performed on the individual biological response data were able to discriminate between the two study areas as well as the contaminated sites from their respective local reference sites. The two contaminated sites outside the cities of Sundsvall (station S1) and Gävle (station G1) were characterised by different biomarker response patterns. Mussels at station S1 showed a low condition index, increased heart rate recovery time and phagocytosis activity coinciding with the highest tissue concentrations of some trace metals, polycyclic aromatic hydrocarbons and organotins. At station G1 the highest organochlorine pesticide concentration was recorded as well as elevations in glutathione S-transferase activity, thiamine content and low lysosomal membrane stability. Significant variability in the geno- and cytotoxic responses and bioenergetic status was also observed at the different caging stations. The results obtained suggest that different chemical mixtures present in the study areas cause variable biological response patterns in organisms.

[Total protein in crawfish hemolymph as a parameter of functional state of animals and biomarker of quality of habitat].

Analysis of total protein in hemolymph was performed by Lowry method on sexually mature crawfish Pontastacus leptodactylus. The total protein content in the crawfish hemolymph was studied for one year. The protein concentration varied widely, amounted to from 12 to 95 mg/ml, and depended on season and the moulting cycle phase. There are presented histograms for distribution of animals for the protein level for different seasons and their character is analyzed. In summer the amount of protein is maximal prior to moult and decreases by 40 % at once after it. There is studied the diapason of total protein concentrations in hemolymph, in which survival of crawfish at unfavorable changes in habitat is maximal. The adaptive possibilities of crawfish with the low protein content are reduced. The crawfish with the protein concentration in hemolymph lower than the "critical" one were submitted for different time by action of hydroquinone (1 g/l) used as a model toxicant. A brief action did not affect the protein content in hemolymph. At a long toxic action the protein level in hemolymph fell, on average, by 40%, which preceded the death of the animals. Possible mechanisms of positive correlation of the protein concentration in the crawfish hemolymph and of their survival at deterioration of quality of the water medium are discussed.

[Evaluation of functional state of crayfish Pontastacus leptodactylus in normal and toxic environment by characteristics of their cardiac activity and hemolymph biochemical parameters].

The work deals with study of basic characteristics of cardiac activity (HR and stress-index) and hemolymph protein parameters in the crayfish Pontastacus leptodactylus. The main criteria of the crayfish selection are developed for formation of the animal reference groups available for subsequent toxicologic experiments. The action of a model toxicant, hydroquinone (often present in waste water), at a concentration of 1 g/l on parameters of the crayfish cardiac activity at various exposition time, its effect on circadian cardiac activity and on the hemolymph total protein were studied. At its short-term exposure, hydroquinone produced a temporary increase of HR and stress-index, but had no marked effect on the total protein parameters in hemolymph. At long action (for one day), hydroquinone led to a considerable tachycardia, disturbance of the circadian cardioactivity and to a decrease by 40% of the hemolymph total protein. In 50% of cases the toxicant caused death of the animals either in the course of its action or at period of washout from the toxicant. Mechanisms of the toxic action of hydroquinone at various levels of organization are discussed.

[Study of circadian activity in the crayfish Pontastacus leptodactylus during their multimonth stay in the river water flow].

By the method of non-invasive on-line recording and processing of photoplethysmograms of testaceous invertebrates, the circadian rhythm of cardiac activity was studied in the crayfish Pontastacus leptodactylus by recording for several months the heart rate (HR) and stress-index (characteristics of variational pulsometry). The crayfish were kept in the natural running water in the regime of natural illumination alteration (the first group) or at constant artificial illumination of low intensity (the second group). The circadian rhythm was more frequent and more distinct in crayfish of the first group. The criteria were established to determine the appearance and stabilization of the nocturnal, active rhythm phase: an increase of HR by more than 30% as compared with daytime rest period and duration of such increase for at least 2.5 h. The stress-index has been shown to be a reliable parameter of the beginning of the nocturnal phase of cardioactivity, while preservation of the typical circadian rhythm can be considered as a bioindicator in the biomonitoring systems of the quality of superficial waters.

[New measurement standard for cytofluorimetry]. / Novyi étalon dlia tsitofluorimetrii.

New phosphor crystals, on the basis of zeolit, activated by tin (Sn), appeared to be a very suitable permanent fluorescent test-object for setting up microscopes, intructing new users and for calibrating microfluorimeters. Their properties provide the control of conditions of various fluorescent experiments in both visible and ultraviolet regions. The crystal size may vary from 1 to 100 micron along the facet. Spectral, polarization and fading fluorescence characteristics of the new crystals are described.