Development of a polyclonal antibody-based indirect competitive ELISA for the determination of tetrodotoxins in marine ribbon worms (NEMERTEA) and its comparison with high performance liquid chromatography-tandem mass spectrometry.

Tetrodotoxin (TTX) is a potent neurotoxin frequently occurring in marine organisms along with its numerous analogues. To determine the total TTX content, we developed an enzyme-linked immunosorbent assay (ELISA) technique utilizing polyclonal antibodies against TTX. The technique was tested using extracts of marine worms of the phylum Nemertea and confirmed by HPLC-MS/MS. It proved to be suitable for a preliminary assessment of the toxicity of marine organisms.

Tetrodotoxin and its analogues profile in nemertean species from the sea of Japan.

For the first time search for tetrodotoxin (TTX) and its analogues in the extracts of nemerteans using HPLC-MS/MS was performed. TTX analogues were detected in two nemertean species in addition to TTX: 7 analogues were detected in the extract of Cephalothrix simula, 3 analogues - in the extract 11-norTTX of Kulikovia manchenkoi. Presence of 5-deoxyTTX, 11-deoxyTTX, 5,6,11-trideoxyTTX and -6(R)-ol in nemerteans was shown for the first time.

[Method for the calculation of the 50% effective dose of biologically active agents]. / Sposob vychisleniia 50% éffektivnoi dozy biologicheski aktivnykh agentov.

A newly proposed method for the mathematical and graphic determination and calculation of ED50 (LD50) on the abscissa at the meeting point of the cumulate of dead and the cumulate of survived animals (in absolute figures) in "dose-effect) experiments is described. "The method of meeting cumulates) for the calculation of ED50 (LD50) is simple, eliminates unnecessary calculations, yields results, highly similar (95-100%) to those obtained by other methods and may be used in different medico-biological studies.

[Interactions of certain sapronotic infection pathogens in mixed cultures on a solid medium at different temperatures]. / Vzaimodeistvie vozbuditelei nekotorykh sapronozov v smeshannykh kul'turakh na plotnoi srede pri raznykh temperaturakh.

Under experimental conditions within the time limit of 21-35 days the causative agents of sapronotic infections in binary cultures, grown on a solid medium at 37 degrees C, 25-27 degrees C and 6-8 degrees C, interacted with one another transbiotically and through contact, their interactions having the character of amensalism, commensalisms-amensalism, competitive equilibrium, antibiosis. Irrespective of the initial density, a change in the species composition was observed, one of them playing the dominating role. At 37 degrees C mutual antagonism of Yersinia pseudotuberculosis and Pseudomonas aeruginosa killed both cultures. P. aeruginosa cells were also killed when cultivated at 37 degrees C jointly with Listeria monocytogenes, the most resistant species under experimental conditions. While studying the character of microorganisms interactions the method of contacting cultures on a solid medium was shown to give more information in comparison with the "cross-strip" method. Possible interspecific relationships between the causative agents of sapronotic infections under natural conditions are discussed.

[The model of radiation shielding of the service module of the International space station]. / Model' radiatsionnoi zashchishchennosti sluzhebnogo modulia Mezhdunarodnoi kosmicheskoi stantsii.

Compared and contrasted were models of radiation shielding of habitable compartments of the basal Mir module that had been used to calculate crew absorbed doses from space radiation. Developed was a model of the ISS Service module radiation shielding. It was stated that there is a good agreement between experimental shielding function and the one calculated from this model.

[Signal identification of potentially pathogenous Yersinia]. / Signal'naia identifikatsiia potentsial'no patogennykh iersinii.

A four-tube method with diagnostic nutrient media is proposed for differentiating between pathogenic and apathogenic Yersinia. Yersinia cultures are detected by inoculating typical or suspected colonies from solid media to media with lactose, glucose, urea, and indicators. Subsequent culturing in three other media (with sucrose and sorbitol, with esculin, rhamnose, and salicin, and with pyrasinamide) and the use of appropriate indicators help detect potentially pathogenous pseudotuberculous and enteric Yersinia of 1B, 2, 3, and 5 biovars from apathogenic species and variants. The method is simple, rapid, economic, reliable, and is recommended for clinical laboratory diagnosis.

[Modification of method of detection virulent Yersinia using crystal violet]. / Modifikatsiia metoda vyiavleniia virulentnykh iersinii s kristalli cheskim fioletovym.

A modified crystal violet method and common agarose medium are proposed for culturing Yersinia before staining. The dish variant is recommended for large quantities and the tube variant for individual strains. Up to 25-30 colonies (plaques) are inoculated into a petri dish and a "dash" inoculation is made into oblique agar in tubes. The cultures are incubated for 24 h at 37 degrees C. After 3-min staining (100 micrograms/ml) of the resultant cultures three phenomena are observed due to the presence of a virulence plasmid with molecular weight of 45-48 megadalton in the strain: violet staining (CV+ test), adhesion to substrate (adhesion+), and adhesion of Yersinia cells to each other (autoadhesion+). Strains with these phenotypical signs are virulent. The proposed method is simple, informative, and reliably detects virulent strains of Yersinia among apathogenic and pathogenic species (variants) isolated from clinical or epidemiologically significant materials.

[DNA, RNA, and protein biosynthesis in cells of Yersinia pseudotuberculosis at various cultivation temperatures]. / Biosintez DNK, RNK i belka v kletkakh Yersinia pseudotuberculosis pri raznykh temperaturakh kul'tivirovaniia.

Y. pseudotuberculosis cells cultivated at temperatures of 37 degrees C and 8 degrees C were found to be capable of incorporating exogenic precursors into DNA, RNA and protein. The linear growth of thymidine incorporation occurred during 8 hours of cultivation at 37 degrees C, then the amount of the incorporated label decreased. At 8 degrees C the level of thymidine incorporation into DNA gradually increased for 80 hours and longer, but not reaching the level of incorporation observed at 37 degrees C. The incorporation of uridine into RNA of Y. pseudotuberculosis cells reached its maximum after 4 hours of cultivation at 37 degrees C, at a lower temperature of cultivation the incorporation of uridine into bacterial cells was almost linear, though slower, and lasted for 20 hours. The content of radioactive alanine in Y. pseudotuberculosis protein increased during 16 hours of cultivation at a high temperature, while at 8 degrees C the growth of the incorporation level lasted for at least 40 hours. For all precursors under study the incorporation rate into the cell biopolymers at the initial stages of cultivation was higher at 37 degrees C, than at a lower temperature.

[Interactions between bacteria of the genus Yersinia in a water environment]. / Vzaimodeistviia mezhdu bakteriiami roda Yersinia v vodnoi srede.

Under the conditions of a prolonged experiment in sterile water at 4-6 degrees with no outside supply of any substances pathogenic Y.pseudotuberculosis, Y.enterocolitica and other Yersinia species in pure and binary cultures remained viable for the period of 12-24 months (the term of observation). In monocultures, all Yersinia actually returned to their initial amounts. In associations with Y.enterocolitica O:3, Y.frederiksenii and Y.intermedia, a delay in the lag-phase (1-2 weeks) was observed in Y.pseudotuberculosis, while in the other pair they stimulated the lag- and log-phase in Y.enterocolitica O:8. In other associations, the growth of different cultures was balanced; 12 and 24 months later their amount characteristics exceeded the initial ones by 2-4.9 and 1-3.5 orders respectively. The possibility of interaction with the signs of protocooperation between different Yersinia cells under natural conditions is discussed.

[The pathomorphosis of opisthorchiasis]. / Patomorfoz opistorkhoza.

Based on the data available in the literature and their own findings, the authors have come to the conclusion that the clinical picture of opisthorchiasis has undergone profound changes in the past decades, which may be regarded as a manifestation of induced and reduced pathomorphism. Uninduced pathomorphism appears as decreased invasion rates and as acute forms. Induced pathomorphism shows up in reduced invasion or by timely liquidation of invasion. The etiological and pathogenetic role of Helicobacter pylori in the development of the gastroduodenal pathology in patients with opisthorchiasis is considered as a manifestation of false pathomorphism.

[Pasteurized milk as a factor in the transmission of the causative agents of yersiniosis]. / Pasterizovannoe moloko kak faktor peredachi vozbuditelei iersiniozov.

From 43 (35.8%) out of 120 samples of pasteurized milk used by volunteers 182 cultures of five Yersinia species--Y. enterocolitica, biovar 1 (70.3%), Y. intermedia (18.1%), Y. frederiksenii (7.7%), Y. kristensenii (3.3%) and Y. aldovae (0.5%)--were isolated in the course of bacteriological studies carried out in 1987-1990. The isolated Yersinia cultures belonged to nonpathogenic pyraminidaze-positive serovars. Yersinia pathogenic bio/serovars (4/O3, 2/O9, 1B/O8) were not detected. No deviations from the normal state were registered in the volunteers drinking pasteurized milk, and Yersinia could be isolated from their feces only during the first 3 days following milk consumption. In 390 patients examined for the presence of Yersinia infections the isolation rate of Yersinia of biovar 1 (99.6% of the cultures) varied between 4.4% and 21.3% and correlated with the increase of the isolation rate from milk (13.6% to 53.9%). The results of the study suggest that unboiled pasteurized milk contributes to the spread of Yersinia carriership among the population.

[The isolation of Yersinia intermedia strains with a plasmid of 82-megadalton molecular weight in natural populations of Yersinia]. / Vydelenie shtammov Yersinia intermedia s plazmidoi molekuliarnoi massy 82 megadal'ton v prirodnykh populiatsiiakh iersinii.

For the first time Y. intermedia strains containing plasmids with a molecular weight of 82 MD have been detected in natural populations of urease-positive Yersinia. Such populations have been isolated from two species of birds and from the soil in the area where they have been killed (the Maritime Territory), as well as from washings from the surface of onions in a vegetable store (Chita Province). The strains, administered orally to white mice, proved to be nonpathogenic. Plasmids with a molecular weight of 82 MD are supposed to occur in natural populations of other Yersinia species.

[Ultrastructure of neuromuscular synapses of 3 types of muscle fibers of the rat diaphragm in acute chlorophos poisoning]. / Ul'trastruktura nervno-myshechnykh sinapsov trekh tipov myshechnykh volokon diafragmy krysy pri ostrom otravlenii khlorofosom.

A comparative analysis of changes in ultrastructure of neuro-muscular synapses of three types has been studied in the rat diaphragmal muscle at an acute poisoning with chlorophos. A high stability to the damaging action of chlorophos in white muscle fibers has been revealed in comparison with other types. The most essential changes of the ultrastructure have taken place in slow intermediate fibers. These differences are evidently connected with certain peculiarities in morphofunctional organization of calcium-sequestring ++ components of three types of muscle fibers (sarcotubular system, mitochondria) and presence of parvalbulin.