Utilization of serological methods in the retrospective diagnosis of cholera and in detecting vibrion carriers]

Sensitivity and specificity of the three serological methods were studied comparatively: the vibriocidal test, the reaction of bacterial agglutination and of indirect hemagglutination, with the use of erythrocytes sensitized with the vibrio lyzate, cholera species O-antigen and cholerogen. Investigations were conducted with the blood sera of cholera patients, vibrio carriers and contacts. Vibriocidal test proved to be the most sensitive; its data correlated with the results of bacterial agglutination and indirect hemagglutination with erythrocytes, sensitized with the lysate of the vibrios and the cholera O-antigen. None of the used serological methods provided a 100% coincidence with the results of bacteriological analysis. The frequency of detection of anticholera antibodies decreased in the following order: cholera patients, vibrio carriers, contacts.     

Feldspar Tunneling by Fungi along Natural Productivity Gradients

Recently, it was hypothesized that ectomycorrhizas hyphae are involved in mineral tunneling. We evaluated the role of ectomycorrhizas in mineral weathering and the ecosystem influx of basic cations by correlating mineral tunnel density to ectomycorrhizas density in two forest productivity gradients. The gradients, two gentle slopes in northern Sweden, are the result of groundwater movement and are characterized by reduced productivity upslope due to lower nitrogen availability. As expected, ectomycorrhizas density in the O horizon was higher upslope, where nitrogen availability was lower and where the vegetation was dominated by ectomycorrhizas plant species. We consistently found that tunnel formation in mineral grains was more intense in nutrient-poor sites, indicating a higher contribution of fungi to ecosystem influx of potassium and calcium. ectomycorrhizas density was positively correlated with feldspar tunnel density in the upper 2 cm of the E horizon. This suggests that ectomycorrhizas are involved in mineral tunneling. We discuss the possible involvement of ericoid mycorrhizas and saprotrophic fungi in feldspar tunneling and the role of the weathering status of mineral grains as additional factors controlling mineral funneling.     

Intensity of the production of rheumatoid factor in patients with different degree of sensitization to Borrelia garinii antigens

The content of rheumatoid factor and serum IgA, IgM and IgG in patients with different degree of sensitization to B. garinii antigens is evaluated. An increase in the titer of rheumatoid factor in patients with a high content of antibodies to Borrelia was established. In addition, an increased concentration of serum immunoglobulins in the presence of Borrelia infection was registered. The mechanisms of autoimmune reactions are discussed, proceeding from the biological properties of the causative agent of Lyme disease.     

Intensity of the production of rheumatoid factor in patients with different degrees of sensitization to Borrelia garinii antigens

The content of rheumatoid factor and the levels of IgA, IgM, IgG in patients with different degrees of sensitization to Borrelia garinii antigens were studied. The titer of rheumatoid factor was found to increase in accordance with the growth of the levels of anti-Borrelia antibodies. A rise in the concentration of serum immunoglobulins simultaneously with the development of Borrelia infection was registered. The mechanisms of autoimmunization are discussed, taking into account the known biological properties of the causative agent of Lyme disease.     

Changes in Concentration of Calcium Ions and the Rhythm of Protein Synthesis in the Culture of Hepatocytes

We studied the effects of the chelating agents of extra- and intracellular calcium ions, EGTA and BAPTA-AM, and of the inhibitor of Ca²⁺release from the reticulum, TMB-8, in the kinetics of protein synthesis in hepatocyte cultures. We also studied dense cultures capable of self-synchronization of protein synthesis oscillations and diluted cultures, in which synchronization is induced by phenylephrine or gangliosides (standard preparation of total gangliosides from the bovine brain). Preincubation of the diluted or dense cultures in the presence of 2 mM EGTA for 1–2 h with subsequent protein assay in a medium with EGTA did not affect the kinetics of protein synthesis: no rhythm was found in the diluted cultures, while it was preserved in the dense cultures. When the diluted cultures preincubated in the presence of EGTA were placed in a medium with EGTA and 2 M phenylephrine for 2 min, the rhythm was visualized. The treatment of diluted cultures with 100 M TMB-8 for 5 or 10 min with subsequent washing and incubation in a medium with 3 M gangliosides led to visualization of the protein synthesis rhythm, i.e., to the synchronization of oscillations, while no rhythm was found in the standard cultures. Preincubation of the diluted cultures in a medium with 10, 15, or 20 M BAPTA-AM for 1 h did not affect the kinetics of protein synthesis. When, after such preincubation, the diluted cultures were placed in the medium with gangliosides, the rhythm was visualized. In the dense cultures, normally capable of self-synchronization, no rhythm of protein synthesis was found after their treatment with 10–20 M BAPTA-AM for 1 h. The transfer of such cultures in the medium with gangliosides led to visualization of the rhythm. Thus, calcium affects the kinetics of protein synthesis: after the rise of Ca²⁺in the cytoplasm was blocked, the rhythm of protein synthesis was not visualized due, supposedly, to disturbed mechanisms of medium conditioning. However, exogenous gangliosides in the dense or diluted cultures preincubated in the presence of BAPTA-AM ore TMB-8 allowed the rhythm visualization, i.e., synchronization may not depend on changes in the intracellular calcium concentration.     

Initial characteristics and isolation of bacterial mutants with altered ability to transpose Tn9

The method allowing the induction of bacterial mutations affecting Tn9 transposition from the bacteriophage genome to the Escherichia coli chromosome is described. Neither impaired ability of cells to adsorb bacteriophages, nor phage DNA degradation in the mutant cells were observed in the transposition-defective mutants isolated by the method. This led us to the conclusion that the isolated mutants were indeed defective in the transposition of Tn9.     

Transposition and inheritance of Bordetella Tn-element in Escherichia coli K12

B. pertussis genetically mobile element TnBp3 integrates the plasmid in E. coli chromosome. During culturing under nonselective conditions the majority of cells of some E. coli strains lose the kanamycin resistance marker, which indicates the instability of TnBp3 inheriting. The stability of inheriting the integrated structure is higher in E. coli cells with recB-21 recC-12 sbcB-2 mutations. The role of RecBC recombination system in extrusion of TnBp3 is discussed.