The ichthyofauna of coastal waters southwest of Crimea in 2003–2004

The ichthyofauna of the narrow coastal zone of southwest Crimea in 2003–2004 was represented by 79 fish species belonging to 36 families. The structure of the species composition of eggs, larvae, and adult fish in these years indicated to its restoration in comparison with the late 1980s to early 1990s. The abundance of commercial fish increased: Engraulis encrasicolus ponticus, Trachurus mediterraneus ponticus, and Mullus barbatus ponticus. The quantity of migratory fish increased: Pomatomus saltatrix and Sarda sarda. The presence in winter catches of Trachurus mediterraneus ponticus and Pomatomus saltatrix indicated favorable conditions for their wintering off South Crimea. Appearance in catches of the fish of elder age groups is evidence of the restoration of their age structure. The competitor for food Mnemiopsis leydyi still influences the food resources of the fish and, thus, their survival. If they appear in plankton simultaneously, the abundance of larvae drastically decreases. The obtained data indicate to the vulnerability of coastal biocenoses to anthropogenous impact and to the necessity of monitoring of fish resources and of their protection.     

Involvement of Microtubular Network and Its Motors in Productive Endocytic Trafficking of Mouse Polyomavirus

Infection of non-enveloped polyomaviruses depends on an intact microtubular network. Here we focus on mouse polyomavirus (MPyV). We show that the dynamics of MPyV cytoplasmic transport reflects the characteristics of microtubular motor-driven transport with bi-directional saltatory movements. In cells treated with microtubule-disrupting agents, localization of MPyV was significantly perturbed, the virus was retained at the cell periphery, mostly within membrane structures resembling multicaveolar complexes, and at later times post-infection, only a fraction of the virus was found in Rab7-positive endosomes and multivesicular bodies. Inhibition of cytoplasmic dynein-based motility by overexpression of dynamitin affected perinuclear translocation of the virus, delivery of virions to the ER and substantially reduced the numbers of infected cells, while overexpression of dominant-negative form of kinesin-1 or kinesin-2 had no significant impact on virus localization and infectivity. We also found that transport along microtubules was important for MPyV-containing endosome sequential acquisition of Rab5, Rab7 and Rab11 GTPases. However, in contrast to dominant-negative mutant of Rab7 (T22N), overexpression of dominant-negative mutant Rab11 (S25N) did not affect the virus infectivity. Altogether, our study revealed that MPyV cytoplasmic trafficking leading to productive infection bypasses recycling endosomes, does not require the function of kinesin-1 and kinesin-2, but depends on functional dynein-mediated transport along microtubules for translocation of the virions from peripheral, often caveolin-positive compartments to late endosomes and ER – a prerequisite for efficient delivery of the viral genome to the nucleus.     

Defining the requirements for Hsp40 and Hsp70 in the Hsp90 chaperone pathway

The Hsp90 chaperoning pathway and its model client substrate, the progesterone receptor (PR), have been used extensively to study chaperone complex formation and maturation of a client substrate in a near native state. This chaperoning pathway can be reconstituted in vitro with the addition of five proteins plus ATP: Hsp40, Hsp70, Hop, Hsp90, and p23. The addition of these proteins is necessary to reconstitute hormone-binding capacity to the immuno-isolated PR. It was recently shown that the first step for the recognition of PR by this system is binding by Hsp40. We compared type I and type II Hsp40 proteins and created point mutations in Hsp40 and Hsp70 to understand the requirements for this first step. The type I proteins, Ydj1 and DjA1 (HDJ2), and a type II, DjB1 (HDJ1), act similarly in promoting hormone binding and Hsp70 association to PR, while having different binding characteristics to PR. Ydj1 and DjA1 bind tightly to PR whereas the binding of DjB1 apparently has rapid on and off rates and its binding cannot be observed by antibody pull-down methods using either purified proteins or cell lysates. Mutation studies indicate that client binding, interactions between Hsp40 and Hsp70, plus ATP hydrolysis by Hsp70 are all required to promote conformational maturation of PR via the Hsp90 pathway.     

Pertussis toxin suppresses dendritic cell-mediated delivery of B. pertussis into lung-draining lymph nodes

The adenylate cyclase (ACT) and the pertussis (PT) toxins of Bordetella pertussis exert potent immunomodulatory activities that synergize to suppress host defense in the course of whooping cough pathogenesis. We compared the mouse lung infection capacities of B. pertussis (Bp) mutants (Bp AC⁻ or Bp PT^–) producing enzymatically inactive toxoids and confirm that ACT action is required for maximal bacterial proliferation in the first days of infection, whereas PT action is crucial for persistence of B. pertussis in mouse lungs. Despite accelerated and near complete clearance from the lungs by day 14 of infection, the PT⁻ bacteria accumulated within the lymphoid tissue of lung-draining mediastinal lymph nodes (mLNs). In contrast, the wild type or AC⁻ bacteria colonized the lungs but did not enter into mLNs. Lung infection by the PT⁻ mutant triggered an early arrival of migratory conventional dendritic cells with associated bacteria into mLNs, where the PT⁻ bacteria entered the T cell-rich paracortex of mLNs by day 5 and proliferated in clusters within the B-cell zone (cortex) of mLNs by day 14, being eventually phagocytosed by infiltrating neutrophils. Finally, only infection by the PT⁻ bacteria triggered an early production of anti-B. pertussis serum IgG antibodies already within 14 days of infection. These results reveal that action of the pertussis toxin blocks DC-mediated delivery of B. pertussis bacteria into mLNs and prevents bacterial colonization of mLNs, thus hampering early adaptive immune response to B. pertussis infection.     

Use of quantitative immunofluorescence for determining the adsorption capacity of magnetic immunosorbents

The adsorption capacity of microgranulated polyacrylamide magnetic immunosorbents has been studied by the method of quantitative immunofluorescence as applied to the causative agents of plague, cholera, and melioidosis. Similar regularity in the dynamics of antigen adsorption on the granules of magnetic immunoadsorbents has been established. This regularity consists in the direct relationship between this process and the concentration of infective agents interacting with magnetic sorbents.     

The expression of hetero-organic antigens of kidney origin on the surfaces of cultured rat hepatocytes under the influence of the narrow-band fractions of non-histone chromosomal proteins]

Narrow fractions of nonhistone chromosomal proteins (NHCP) eluted with 0.4-0.5 M NaCl from the phosphocellulose column stimulate expression of hetero-organic antigens of kidney origin on the membrane of intact hepatocytes cultured in suspension. These fractions of NHCP were isolated from the intact rats kidney, from cells of hepatoma 27 and Zajdela hepatoma, and from the carcinogenic liver after a single diethylnirozamine injection. The membrane hetero-organic antigens were identified by means of indirect immunofluorescence using specific immune serum.     

Radioprotective effect of nucleosides and nucleotides and the mechanism of action of adenosine

Adenosine and a majority of adenine mononucleotides have a radioprotective action; adenine and 2'-deoxyadenosine have no radioprotective effect, and that of 3',5'-cAMP only approaches the detectable level. Ribo- and deoxyribonucleosides and nucleotides of guanine, uracil, thymine, and cytosine have no protective action. Dipyridamole increases and alkylxanthines block the radioprotective effect of adenosine. So it follows that the radioprotective effect is realized via A-receptors of the plasmatic membrane external surface.     

Tetracycline inactivation by magnesium sulfate in testing for microbial contamination by the membrane filtration method]

It was shown that the residual amounts of tetracyclines adsorbed on membrane filters may be inactivated by addition of 2M magnesium sulphate solution to the agar for placing the filters after filtration. The antibiotic inactivation increases the possibilities of the test for antibiotic sensitivity of the microflora present in the drugs and may be used in determination of microbial dissmination of non-injection tetracyclines.