[PARASITE FAUNA AND STRUCTURE OF PARASITE COMPONENT COMMUNITIES IN THE MINNOW PHOXNUS PHOXINUS (LINNAEUS, 1758) IN AN OIL POLLUTED WATERSTREAM].

In June 1992 and July 1996, 238 minnow specimens of the 2+--3+ age were collected from 5 parts of the Kolva River and studied using the standard technique of the general parasitological dissection. Comparative analysis of parasite fauna and the structure of component parasite communities in the minnow from ecologically safe and variably polluted parts of the river was performed. The analysis had demonstrated that the increase in the water pollution by domestic wastewater, washings of fertilizers from agricultural fields and private country houses, cattle farm drains (Dorovskikh et al., 2005, 2008), and oil results in the change of dominant parasite species of the minnow, alteration of the sum of errors in the regression equation characterizing the spread of biomass values of the species forming the parasite community, changes in the "graphic" structure of the community, and alteration of the index D(E)'. It is proved, that the high concentration of nutrients has a destructive effect on natural systems, and, at the same time, causes the process of self-organizing, leading to the alteration of the community structure. As soon as even a small part of nutrients is stopped to come into the reservoir, and the quality of environment is restored, the community restores its structure.

[Seasonal dynamics of the parasite fauna and of the component community structure of parasites of the minnow Phoxinus phoxinus (L.) from the Pechora River. 3].

During January May, 2007, 105 specimens of minnow of the 2+ -- 3+ age were col- lected from the Pechora River in the central homestead of the Pechora-Ilechsky Natural Reserve, and studied using the standard technique of the general parasitological dissection. It was concluded that in a period of studies the component parasite community was in a formation process.

[Results of the study of the geographical variability of the parasite fauna and of the structure of component communities of the minnow parasite Phoxinus phoxinus (L.) 1. Basins of the Kama and Northern Dvina Rivers].

In the basin of the Kama River, in upper Vychegda River, and in tributaries of the upper Northern Dvina River, the parasite fauna of the minnow is monotonous and component communities of parasites are mature (balanced, according to Pugachev, 1999). They are completely formed in June.

[Seasonal dynamics of the fauna and of the component community structure of parasites of the minnow Phoxinus phoxinus (L.) from the Pechora River. 2].

It is demonstrated that the component community of parasites of the minnow in the midle Pechora River in September-Decemner corresponds in its characteristics to the forming community, when relations between species in the community are formed again, but the rate of these transformation is significantly lower than in spring-summer.

[Quantitative analysis of seasonal dynamics of the species structure in a component parasite community of the minnow Phoxinus phoxinus (L.) of the Pechora River].

Earlier analysis of a seasonal succession of fish parasites assemblage was, as a rule, performed in May-October. At the same time, winter season can be important in seasonal dynamics of the assemblage. In the present work, quantitative analysis of complete seasonal dynamics of species structure of fish assemblage parasites with an example of the adult minnow of the river Pechora was performed. The new stable state of parasites assemblage of the minnow, corresponding to winter season of its existence, is revealed. Irrespective of population density or a biomass of parasitic assemblages of the minnow, obtained dynamic phase portraits well reflect their seasonal succession.

[Seasonal dynamics of the parasite fauna and of the component community structure of parasites of the Minnow phoxinus phoxinus (L.) from the Pechora River].

The material represented by 120 specimens of minnow of the age 2(+)-3* was collected according to the standard technique from the Pechora River of the Pechora-Ilechsky reserve in the region of Central homestead during May-September 2006. Three stages of the component parasite community included: the community in the process of formation (May-June), the formed community (June), the destroying community (July and August), the community in the process of formation (August and September).

[Structure of the component community of parasites of Gymnocephalus cernuus (Linnaeus, 1758) in different seasons].

In the conditions of middle stream of Vychegda River, the species diversity of parasite community associated with Gymnocephalus cernuus was found to be maximal in March and minimal in September. It is shown, that during a year the parasite community passes through the phases of development in December-March, completion in May-June, and destruction in July-September, which form the annual cycle of the community.

[Structure of component parasite communities in the grayling, Thymallus thymallus L. (Salmoniformes, Thymallidae), and minnow, Phoxinus phoxinus L. (Cypriniformes, Cyprinidae), from the upper reaches of the Pechora River].

A comparative analysis of parasite communities in the grayling and minnow has been performed. These communities differ in the number of constituent species and in that the community of the minnow is dominated by one allogenic species, whereas that of the grayling usually has two dominants, both being autogenic species. The values of species diversity indices characterizing these communities are also different. Differences between the parasite communities of these fish species reflect the position of their hosts in the hydrobiocenosis. Species prevailing in both communities are classified as specialists, which is characteristic of parasite communities of the boreal-piedmont faunal complex. Both these communities consist of three species groups distinguished by their proportions in the total biomass, which indicates that parasitic communities are structured in a certain way and that the distribution of species in them in not random.

[Age-related and individual psychological differences in student behavior under conditions of the reward choice].

Strategies of behavior of choice between the probability (100-0%) and value of the reward (scored as 1-5 or 6-10 on a 10-point scale) depending on the traits of impulsivity/reflectivity, anxiety, and emotional state were studied in schoolchildren at the age of 7-8 (form 1-2), 9-10 (form 3-4), and 11-14 (form 5-7). Differences in behavioral strategies were highest among the children who "worked" under conditions of 50-10% probability of getting a valuable reward. Children who more frequently chose lower scores but occurring with the highest (100%) probability were referred to as "careful", and those who chose higher scores with lower probability were referred to as "inclined towards risky behavior" ("risky"). On this principle, schoolchildren of each age group were assigned to "risky", "moderately risky", moderately careful", and "careful" groups. Individual-psychological differences between the groups were more pronounced at the age of 11-14 years than at the age of 7-8 years. Under conditions of 25% probability of getting a valuable reward, differences in behavioral strategy were essential between the "risky" and "careful" group; under conditions of 10% of probability, the differences between the "moderately risky" and the remaining groups were most pronounced. Choice of a reward received with lower probability under conditions of uncertainty (50-10%) was performed with longer latency than the choice of the reward received with 100% probability. There were more "careful" children in the 3th-4th forms, a "moderate inclination to risky behavior" prevailed in the 5th-7th forms. From the 1st to 7th form, impulsivity prevailed in children "moderately inclined to risk", whereas there were more reflective children in "careful" and "moderately careful" groups. Choice behavior had an impact on the emotional state of children. Heart rate increased after the choice performance. In "careful" children scores of personal and class anxiety were higher than in the "moderately risky" group.

[Component parasite communities in the minnow Phoxinus phoxinus (L.) from ecologically safe and polluted reservoirs].

A comparative analysis of the structure of component parasite communities in the minnow from ecologically safe or polluted to variable extent reservoirs was made. The analysis showed that the increase of the reservoir pollution by everyday drains, washings of fertilizers from the fields around and the dacha sections causes the change of dominant parasite species in the minnow, alteration of the sum of errors in the regression equation characterizing the spread of values of biomasses of the species forming the parasite community, and change of the "graphic" structure of the community. It is proved, that the high concentration of biogens has a destructive effect on natural systems, and at the same time causes the process of self-organizing, leading to the alteration of the community structure. As soon as even a small part of biogens is stopped to come into the reservoir, and the quality of environment is restored, the community restores its structure.

[Dependence of the structure of component parasite communities on host age].

Dependence of the structure of component parasite communities on host age is studied by the example of parasite communities in minnow and grayling from the North Dvina and Pechora rivers basins. Parasite communities from immature host groups are revealed to be different from those in mature fishes by lesser number of parasite individuals and biomass, number of groups discriminated by the ratio of biomasses, and frequently by lesser number of species. Indices of diversity describing parasite communities from hosts of different ages are nearly always the same in the area examined. This observation needs in verification because values of the indices characterizing parasite communities from fishes of different ages are not equal in the parasite communities from grayling of different age from the Pinega river and minnow from the Chovju river (Dorovskikh, 2002).

[Component communities of parasites in the grayling Thymallus thymallus (L.) (Salmoniformes, Thymallidae) and the minnow Phoxinus phoxinus (L.) (Cypriniformes, Cyprinidae) from the Pechora River].

Component communities of parasites of Thymallus thymallus and Phoxinus phoxinus are described. The communities differ in the number of species and in the number of dominate species, which is one in P. phoxinus and usually two in T. thymallus. In the first case the dominate species is allogenic, while in the second case dominate species are autogenic. Values of the species diversity indexes are also different for these communities. The differences between parasite communities of T. thymallus and P. phoxinus underline positions of these hosts in hydrobiocenose. Species specialists take first place in the parasite communities both of the hosts, that is characteristic for the parasite communities of the fishes from the boreal submountain faunistic complex. Parasite communities in both of the hosts consist of three groups of species discriminated by the ratio of their biomasses, that suggests forming of the groups by a coordination of the species biomasses.

[Host age and structure of the component communities of parasites in river minnow Phoxinus phoxinus (L.)].

Species composition and structure of the communities of fish parasites in river minnow Phoxinus phoxinus (L.) from the Pechora river were investigated in two of the Pechora-Ilychsky Biosphere Nature Reserve, Komi Republic. The component communities of the parasites in river minnow are shown to have a one-year cycle including the states of development, completion, and destruction. Communities in the state of development are characterized by a low variety of species, low values of Shannon index, often high values of domination index, presence of only two groups of parasites in the structure described by variational curved of the conditional biomasses of species, deviation of the conditional biomasses of species from the linear regression, and sum of errors of the regression equations lower a threshold value. The communities consist of young individual parasites and their larval stages. Completed community is characterized by the following properties. There are three groups of parasites, differing in allometric index, in the structure, discerned by the ratio of conditional biomasses of the species included. Conditional biomasses of species in ecologically safe reservoirs lie on the segments of straight lines. Species variety reaches its maximum. Species are presented mainly by mature specimens and larval stages of the parasites using fish as intermediate host. Community in the state of destruction shows low values of domination index and relatively small variety pf species. Such community is consist of one or two groups of species, which are represented by mature, oviparous, and dying individuals. There are larval stages of parasites using fish as intermediate hosts. Dominant species or species groups, as well as values of indexes describing the component communities of parasites, can be different in mature river minnow from different geographical regions. However, the number of groups of parasites, formed by the ratio of conditional biomasses, remains constant, and sum of errors of the regression equations characterizing the communities is always below 0.25. Component communities of parasites in young river minnows differ from the communities in mature fishes by lower variety of species. Lower biomass, and lower number of individual parasites. The communities of parasites in 0+ old fishes are often characterized by lesser number of groups of parasites, classified by the ratio of their biomasses, and presence of two dominate species. It is often impossible to count the sum of errors of the regression equations describing spread in values of biomasses of the species forming the community.

[Monosulfated triterpene glycosides from Cucumaria okhotensis Levin et Stepanov, a new species of sea cucumbers from Sea of Okhotsk].

Three compounds were isolated from the fraction of monosulfated triterpene glycosides from Cucumaria okhotensis, a new sea cucumber species, and their structures were elucidated. First of them, okhotoside A1-1, is a new glycoside containing tetrasaccharide sugar moiety; the second, okhotoside A2-1, is a new pentaoside with a glucose residue in the second position of sugar moiety (such a structural peculiarity has been found in holothurians of the genus Cucumaria for the first time); and the third is a previously known pentaoside cucumarioside A0-1 from C. japonica. The species-specificity of the triterpene glycosides from C. okhotensis was revealed, which justifies the description of this sea cucumber as a new species.

[The occurrence of tumors in the minnow Phoxinus phoxinus (L.), their influence upon the parasite fauna, component community of parasites, and organism of the host].

The occurrence of tumors, their influence upon the organism of Phoxinus phoxinus (L.), its parasite fauna, and parasite component community were investigated in the upstream of the Pechora River. According to the data obtained, tumors could occur in the fishes of every age group, but one-year (0+) or two-year (1+) old minnow is affected by tumors more frequently. The tumors lesion extensiveness ranges from 0.02 to 3 %. From 1 to 3 tumors were recorded on one fish specimen. The investigated tumors were in progressive stage (Georgiev, 2000), since the vascular ingrowth and dissemination (in few cases) of the tumors were observed. Tumors are colored in intensive-black and taupe. The taupe tumors usually have a compact capsule at its peripheries, which isolates affected tissue from muscle fibers. In the intensive-black tumors the invasion of tumor cells to the adjacent transversal striated musculature is observed. Distinct symptoms of necrosis are revealed in all slides of the new growths. Blood vessels are formed in most tumors, and the blood flow is recorded before the completion of the vessels forming, that apparently supplies the tumors feeding. Metastases in different organs revealed in several minnow specimens. Tumor affected individuals of the minnow has parasite species complex practically identical (by species list and quantity) with the same of the even-aged unaffected fishes. However, the parasite component communities of the affected individuals are characterized by 4 groups of species, while the parasite component communities of the intact individuals--by 3 groups. The parasite communities of affected and unaffected one-year fishes are similar by the number of the groups of species, but differ in the number of species.

Efficient separation of Thermus aquaticus EF-Tu functional complexes.

A new method for fast separation of the main functional complexes of the elongation factor Tu from Thermus aquaticus has been developed. Binary complexes EF-Tu * GDP and EF-Tu * GDPNP as well as the ternary complex EF-Tu * GDPNP * Leu approximately tRNA were separated from each other by means of HPLC on a hydrophobic sorbent TSK-Gel Phenyl 5PW in a reverse gradient of ammonium sulfate. This technique is suitable for monitoring EF-Tu activity, characterisation of the ratio between different EF-Tu forms in cell extracts, and isolation of individual EF-Tu complexes for structural and functional investigations. In order to illustrate the potentials of the method, we used HPLC on a TSK-Gel Phenyl 5PW matrix to determine the ratio between affinities of GDP and GDPNP for EF-Tu. We found that K(a)(GDP) is about 27 times higher than K(a)(GDPNP) at 37 degrees C, the value being close to the one reported for Thermus thermophilus EF-Tu.

Affinity modification of phenylalanyl-tRNA synthetase from Thermus thermophilus by tRNAPhe transcripts containing 4-thiouridine.

Photoreactive derivatives of tRNAPhe containing residues of 4-thiouridine (s4U) were synthesized by the transcription system of T7 RNA polymerase. Complete substitution of s4U for 16 uridine residues ([16s4U]-tRNAPhe) caused a 14-fold decrease in the catalytic efficiency of aminoacylation of the tRNAPhe transcript by phenylalanyl-tRNA synthetase from T. thermophilus. [1s4U]-tRNAPhe obtained by random incorporation of s4U residues with further isolation of s4U-monosubstituted RNA molecules on an affinity gel has the same kinetic parameters in aminoacylation as the tRNAPhe transcript. The s4U-containing tRNAPhe transcripts were shown to bind covalently to phenylalanyl-tRNA synthetase, and the specificity of modification was demonstrated. The modification stoichiometry determined in this work suggests that the enzyme is a functional dimer. The modification labels both alpha- and beta-subunits of the enzyme, which has an oligomeric structure of alpha2beta2, and forms "cross-linking" products of subunits upon modification with [16s4U]-tRNAPhe. The prevalence of modification of the alpha-subunit suggests that tRNA has contacts with the enzyme, which have not been deciphered previously by X-ray analysis.

A peculiarity of the reaction of tRNA aminoacylation catalyzed by phenylalanyl-tRNA synthetase from the extreme thermophile Thermus thermophilus.

It was confirmed unambiguously that the anomalously high plateau in the tRNA aminoacylation reaction catalyzed by Thermus thermophilus phenylalanyl-tRNA synthetase is a result of enzymatic synthesis of tRNA bearing two bound phenylalanyl residues (bisphenylalanyl-tRNA). The efficiency of bisphenylalanyl-tRNA formation was shown to be quite low: the second phenylalanyl residue is attached to tRNA approximately 50 times more slowly than the first one. The thermophilic synthetase can aminoacylate twice not only T. thermophilus tRNAPhe but also Escherichia coli tRNAPhe and E. coli tRNAPhe transcript, indicating that the presence of modified nucleotides is not necessary for tRNAPhe overcharging. Bisphenylalanyl-tRNA is stable in acidic solution, but it decomposes in alkaline medium yielding finally tRNA and free phenylalanine. Under these conditions phenylalanine is released from bisphenylalanyl-tRNA with almost the same rate as from monophenylalanyl-tRNA. In the presence of the enzyme the rate of bisphenylalanyl-tRNA deacylation increases. Aminoacylated tRNAPhe isolated from T. thermophilus living cells was observed to contain no detectable bisphenylalanyl-tRNA under normal growth of culture. A possible mechanism of bisphenylalanyl-tRNA synthesis is discussed.

[The role of the 3'-CCA sequence in the interaction of tRNA(Phe) from E. coli and Thermus thermophilus with homologous phenylalanyl-tRNA-synthetases]. / Rol' 3'-CCA-posledovatel'nosti vo vzaimodeistvii tRNA(Phe) iz E. coli i Thermus thermophilus s gomologichnymi fenilalanil-tRNK-sintetazami.

The 3'-CCA end of tRNA(Phe) from E. coli and Thermus thermophilus was modified by stepwise degradation and ligation of the shortened tRNA with different trinucleotides (pUpUpA, (pA)3, (pC)3, (pU)3). Kinetic parameters for the aminoacylation reaction of modified tRNAs have been determined. The role of the 3'-terminal trinucleotide of tRNA(Phe) in tRNA binding and aminoacylation by phenylalanyl-tRNA synthetases from E. coli and Thermus thermophilus is postulated.