Harmful Parasitoses on the Russian Southern Far East under Climatic and Demographic Changes.

Progressive expansion of the most hazardous human parasitoses caused by trematodes, cestodes and nematodes has been found on the south of the Russian Far East. Decelerating expansion of the trematode Clonorchis sinensis, an agent of clonorchiasis towards the southern Primorye Territory from the Amur River basin, that began 10-15 years ago, was revealed. A prognosis was made on the activation of the natural foci of clonorchiasis and paragonimiasis. Circulation possibilities are discussed of the highly pathogenic trematode Pagonimus heterotremusar in the South Asian regional ecosystems. Our experiments showed that the freshwater gastropods of the Parajuga genus from the Amur River basin and those of Stenothyra genus from Primorsky Territory were resistant to this trematode infection. Nevertheless, this does not exclude the possibility of this parasite penetration into the Far East region via infection of the local gastropods of other genera.

[New records of bacteria-spirochetes in crystalline style of fresh water gastropods].

Freshwater mollusks belonging to 17 species, in 7 families are examined purposely to search for spirochete bacteria in their crystalline style of the digestive system. As result of this study spirochetes are recorded in gastropod families Amnicolidae, Bithyniidae, Baicaliidae and Benedictiidae, represented by 12 species, occupying different habitats. Gastropods belonging to Valvatidae, Lymnaeidae and Planorbidae, characterized by lack of crystalline style did not include spirochetes in their stomachs. Studied gastropods having spirochetes or free of them are grazers or filter-feeders and mainly phyto-detrito-bacteriaphagous.

Chiral and collinear ordering in a distorted triangular antiferromagnet.

Magnetization, specific heat, and neutron diffraction measurements are used to map out the entire magnetic phase diagram of KFe(MoO4)2. This stacked triangular antiferromagnet is structurally similar to the famous multiferroic system RbFe(MoO4)2. Because of an additional small crystallographic distortion, it contains two sets of inequivalent distorted magnetic triangular lattices. As a result, the spin network breaks down into two intercalated yet almost independent magnetic subsystems. One is a collinear antiferromagnet that shows a simple spin-flop behavior in applied magnetic fields. The other is a helimagnet that instead goes through a series of exotic commensurate-incommensurate phase transformations. In the various phases one observes either true three-dimensional or unconventional quasi-two-dimensional ordering.

Francisella tularensis resistance to bactericidal action of normal human serum.

Lipopolysaccharide and outer membranes from the three virulent encapsulated (Cap(+)) strains of three subspecies of Francisella tularensis and their isogenic avirulent capsule-deficient (Cap(-)) mutants were isolated. It was shown that the Cap cells and their outer membranes almost completely consumed the available complement of normal human serum whereas Cap(-) LPS (R-LPS), Cap(+) cells and their components activated the complement less effectively. Absorption of normal human serum with Cap(-) strain dramatically reduced the complement consumption for homologous strain and its surface structures. This reduction reflected the loss of bactericidal antibodies. Addition of antibodies to whole cells of F. tularensis completely restored complement activity. The cross-absorbing experiments demonstrated that Cap(-) cells more effectively deplete bactericidal antibodies than homologous virulent strain. From these results it can be concluded that normal human serum is bactericidal for serum-sensitive Cap(-) F. tularensis strains through the action of complement initiated by the classical complement pathway and serum resistance of virulent strains is not due to absence of targets for bactericidal antibodies, but is due to their low accessibility because of O-side chains of lipopolysaccharide.

[The dynamics of antibody formation to a vaccinal strain of Francisella tularensis in different immunization regimens]. / Dinamika obrazovaniia antitel k vaktsinnomu shtammu Francisella tularensis pri razlichnykh skhemakh immunizatsii.

The use of different schemes of albino mice immunization either by living or by killed preparations of the vaccine strain of Francisella tularensis when obtaining monoclonal antibodies to the tularemia microbe made it possible to reveal definite regularities in the dynamics of antibody formation. The highest titres of antibodies in sera of animals-donors of splenocytes were obtained during the daily (for 3 days) intraperitoneal immunization of mice with living vaccine or with its thrice administration to the spleen thrice with the interval of 10 days. Revaccination against a background of high titres of antibodies decreased their quantity in blood serum of mice, while that against a background of low titres increased them.