A novel glycosphingolipid from gram-negative aquatic bacteria.

The chloroform-methanol extractable lipids of the Gram-negative fresh-water bacteria Arcocella aquatica NO-502 and Flectobacillus major FM were found to contain an unusual ninhydrin-positive glycolipid. It was purified by two-stage silica gel-column chromatography. By the use of IR and (1)H-NMR spectroscopy, mass spectrometry and chemical-degradation experiment, the lipid was established to be 1-O-monoglycosyl ceramide, the carbohydrate moiety of which was the alpha-pyranose-ring form of 7-desoxy-7-amino-D-manno-heptulosonic acid, or 1-hydroxycarbonyl-6-deoxy-6-amino-alpha-D-mannopyranose. The ceramide portion consisted mainly (by 95% in the A. aquatica glycolipid and 80% in the F. major glycolipid) of 2-N-(2'-D-hydroxy-13'-methyltetradecanoyl)-15-methyl-4(E)-hexad ecasph ingenine. The minor molecular species differed from the major one only in fatty acid structure. The glycolipid accounted for 8 and 11% of the total lipids extracted from A. aquatica NO-502 and F. major FM cells, respectively.     

Human Discrimination of the Angular Velocity of the Vertical Movement of an Acoustic Image in Opposite Directions

The discrimination of the angular velocity of ventrodorsal and dorsoventral movement of an acoustic image was studied in nine test subjects. The experiments were performed using an apparent movement produced by consecutive activation of loudspeakers located along an arc in the vertical plane. The differential thresholds were measured by the minimum increment method. As the velocity of an acoustic image movement in opposite directions increased, the values of its mean absolute differential thresholds increased monotonically. Regression lines plotted by linear approximation of these values did not differ significantly.     

Classification of methylotrophic bacteria according to 5S ribosomal RNA sequencing

5S ribosomal RNA sequences of 33 strains of methylotrophic bacteria were determined. Tentative phylogenetic tree was constructed using the maximum topological similarity principle. Strains under study can be divided into 7 separate branches consistently with the current classification of methylotrophic bacteria. More extensive tree was also built to show the position of methylotrophic bacteria with respect to non-methylotrophic ones. One can conclude that the in contrast to obligate methane-oxidizing bacteria, facultative methylotrophic bacteria do not comprise phylogenetically separate domain on the tree.     

Multifactor immunopharmacological analysis. Effect of rifampicin and low-molecular immunomodulator of microbial origin on the primary immune response to fraction 1 of vaccine EV

Multifactor analysis was applied to combined effect of a low molecular immunomodulator of microbial origin and rifampicin on the primary immune response (increased delayed type hypersensitivity and antibody titer) to the antigens of vaccine EV fraction I. Computer processing of the experimental data provided construction of the 2nd order polynomial models satisfactorily describing cellular and humoral responses in the combined therapy. For increasing the informative capacity of the analysis of the polynomial statistic models it was proposed to develop quasimonofactor relationships reflecting the factor effect on the output with changing of the other factors within the studied ranges. Nomograms (equal level lines at fixed values of one factor) were constructed which provided rapid and correct estimation of optimal values for the regulating parameters (drug doses and administration time). Immunostimulating activity of the microbial immunomodulator was estimated quantitatively and conditions for selective regulation of the cellular and humoral responses were determined.     

Combined action of doxycycline and mytilan on the immune response to tularemia antigen]

Combined action of doxycycline and mytilan, a natural polysaccharide, on the primary immune response to the antigen of the tularemia vaccinal strain in CBA mice was studied. The polysaccharide was used to compensate the immunosuppressive effect of doxycycline high doses on the humoral immune response. The maximum stimulation of the antibody titers as compared to the controls (more than 250 per cent) was observed when mytilan was administered simultaneously with or prophylactically 3 days prior to the antibiotic in doses of 2.5 and 25 mg/kg. The use of mytilan in combination with doxycycline high doses made it possible to compensate the antibiotic-induced decrease of DTH and even to stimulate it as compared to the controls. The highest levels of DTH (150 per cent against the control) were observed when mytilan was administered prophylactically in doses of 2.5 and 11.25 mg/kg 3 days prior to immunization. Mytilan had the highest stimulating effect on antibody production. The combined use of doxycycline and mytilan was characterized by significant stimulation of antibody production and DTH when the dose/time regimens were rational.     

Effect of rifampicin and doxycycline on the chemiluminescence of leukocytes]

The effect of rifampicin and doxycycline on spontaneous and zymosan-induced chemiluminescence of polymorphonuclear leukocytes was studied on guinea pigs. The cells were incubated in the presence of the antibiotics, washed and stimulated by zymosan. Under such conditions rifampicin in therapeutic doses of 0.1 to 10 micrograms/kg and doxycycline in a dose of 100 micrograms/kg potentiated the leukocyte chemiluminescence. Investigation of the antibiotics effect on the cells without washing failed because of the direct interference of rifampicin and doxycycline with the cell-independent stage of the chemiluminescent reaction.     

Comparative multifactorial analysis of combined administration of injection and peroral forms of an antibiotic with a microbial immunomodulator in experimental anthrax

Comparative efficacy of the use of injection and oral dosage forms of rifampicin in the subtherapeutic doses in combination with peptidoglycan , an immunomodulator of microbial origin, was studied in respect to experimental anthracic infection with application of multifactorial analysis. It was shown that the antibiotic and immunomodulator had a pronounced synergistic effect. Polynomial statistic models were developed and nomograms or equal level curves defining the survival rate and average life-span (ALS) of the experimental animals within a wide range of the antibiotic and immunomodulator doses and the peptidoglycan dosing time were plotted. The combined use of the injection rifampicin in the subtherapeutic doses and the immunomodulator provided a significant increase in the survival rate and ALS, whereas the use of the oral antibiotic in combination with the immunomodulator increased only the ALS and not the survival rate. Multifactorial analysis proved to be an optimal methodical approach to comparative study of various antibiotic dosage forms used in combination with immunomodulators under experimental conditions.     

Immunomodulating effect of levamisole in antibiotic therapy

The use of ampicillin, benzylpenicillin, gentamicin, erythromycin, cefamezine or cephaloridine in combination with levamisole aimed at increasing their efficacy and correcting the adverse reactions was studied. Immunological activity of the antibiotics was comparatively characterized by using standard methods. It was shown that the character of the antibiotic effect on the basic factors of nonspecific resistance and immunity was heterogeneous. Schemes for using the antibiotics in combination with levamisole for correcting the detected disorders in the immunity status of the experimental animals were developed.     

Optimal combined use of rifampicin and immunomodulator of microbial origin in experimental Q-Rickettsia infection

Multifactorial analysis of the combined use of rifampicin and an immunomodulator of the microbial origin, such as peptidoglycan, was performed on a model of experimental Q fever in albino mice. On the basis of the experimental results, statistic polynomial models describing the weight of the murine spleens and the titers of the complement-binding antibodies were designed. It was shown that the action of the immunomodulator and antibiotic was highly synergistic with respect to the chemotherapeutic activity and antibody titers. The preventive use of the immunomodulator yielded a 30-fold decrease in a rifampicin therapeutic dose. The use of the immunomodulator also provided a pronounced immunomodulating effect with respect to humoral immunity. Nomographs for optimizing the dose-time parameters of the antibacterial and immunomodulating therapy were plotted.