Electron microscopic and biochemical research on the vacuoles formed in the erythrocytes of frogs as affected by neutral red and novocaine

No lysosomes were found in the frog intact erythrocytes with electron microscope. Under the influence of neutral red (NR-8.7.10(-5) M) and novocaine (N-4.6.10(-3) M) segregation zones (vacuoles) including these substances are formed. Using electron microscopy and morphometry the action of NR and N for 5 minutes up to 48 hours was found to provoke the formation of four types of vacuoles differing in their morphology: with electron-transparent content, with amorphous inclusions and membrane whorls. The dynamics of vacuole formation, of their changes and amount were followed depending on the time of exposition of these substances. Biochemical investigation of both NR and N isolated vacuoles showed in these some activities of lysosomal marker enzymes--acid phosphatase and N-acetyl-beta,D-glucosaminidase. Ultrastructural investigation of acid phosphatase localization in the isolated vacuoles revealed the histochemical reaction product mainly in electron-translucent vacuoles (primary lysosomes) and partly in electron dense ones (secondary lysosomes). On the ground of the above studies a conclusion is made that in frog erythrocytes treated with NR and N lysosome formation is induced to be followed by the induced autophagocytosis and heterophagocytosis. Some possible ways of the vacuolar system formation in frog erythrocytes and the origin of lysosomal hydrolases are discussed.     

Antigenic polysaccharides of bacteria. 35. Establishment of the structure of polysaccharide chains of lipopolysaccharides of Pseudomonas cepacia IMV 4176 and IMV 4202 (Serotype 3)

On mild acid degradation of the Pseudomonas cepacia strain IMV 4176 lipopolysaccharide, two polysaccharides were obtained, one of which is a homopolymer of N-acetyl-D-galactosamine and the other is composed of equal amounts of N-acetyl-D-galactosamine and D-ribose. Partial hydrolysis with aqueous oxalic acid caused depolymerization of the heteropolysaccharide, and the homopolysaccharide was isolated in the individual state. On the basis of methylation and 13C NMR analysis, it was concluded that both polysaccharides are built up of disaccharide repeating units having the following structures: ----4)-alpha-D-GalpNAc-(1----4)-beta-D-GalpNAc-(1---- and ----4)-alpha-D-GalpNAc-(1----2)-beta-D-Ribf-(1----. The heteropolysaccharide from P. cepacia strain 4176 is identical by the structure of the repeating unit to the O-specific polysaccharide of P. cepacia strain IMV 4202 (serotype 3), Pseudomonas aeruginosa O12 and Serratia marcescens O14.     

Analysis of 13C-NMR spectra of oligosaccharides using microcomputers

A microcomputer programme, ANMROL, has been developed to check whether structure of an oligo- or polysaccharide may be elucidated unambiguously from the 13C NMR data. Principles of the programme are described and its application for the series of linear and branched oligosaccharides is discussed.     

Fire behaviour and the invasion of Acacia sieberiana into savanna grassland openings

Following the recent decline in browsing and grazing pressures and changed fire regimes in Queen Elizabeth National Park, Uganda, Acacia thickets have encroached on grassland habitats important for grazing mammals. The objective of this research was to test experimentally the effects of fire behaviour, using simulated and natural fuel loading conditions, on A. sieberiana seedling and sapling regeneration. A high fire intensity (3200 kW m^-1) in natural fuels stimulated high seedling emergence (172 seedlings m^-2) compared to 6 seedlings m^-2 without fire. Also a highly significant linear regression was established between percentage top-kill of seedlings and fire intensities. High fire intensities during late dry season fires were more effective in controlling sapling height growth than early dry season fires of low intensities. A conceptual diagram was developed to show the major factors and possible pathways leading to successful invasion by A. sieberiana into grassland openings of the savanna.     

Structural organization of the genome of paramyxoviruses

The review summarizes the recent papers on the studies of primary structure of genome of a number of paramyxoviruses from the three genera of a family. The cited data demonstrate that despite the common principles of the genetic material arrangement shared by paramyxoviruses, they are variable in the genome, the primary structure of intragenic region, as well as the strategy of coding for some proteins. The data on the arrangement of the genetic material is discussed as useful as a criterion for classification of single stranded viruses with unsegmented genome.     

Role of the NS gene in regulating the synthesis of RNA-segments of the influenza A virus

To find the role of any influenza virus gene in regulation of the RNA-segments replication the transfer of ts-mutants to nonpermissive temperature on the late step of infection has been used (shift-up). The mutants having impaired the NS or NP-genes have been obtained and studied. The transfer of mutants to partially nonpermissive conditions (when the amount of replication is decreased, but it still continues) results in the distinct return to the early mode of replication in ts-mutant with the mutation in NS-gene. This suggests the NS-gene role in replication of viral RNA-segments, in particular, in the switch from the "early" stage of replication to the "late" one. In NP-gene mutant only the decrease in general replication takes place without the shift to "early" replication mode.     

Coefficients of distribution of cyclic polyether macrotetrolide antibiotics between hydrophobic and hydrophilic solvents

Dependence of distribution of 14C-macrotetrolide antibiotics between water and chloroform on the presence of various additives in the aqueous phase was studied with the radioindicator procedure. It was shown that in comparison to distilled water aqueous solutions of chlorine salts of ammonium, potassium and sodium increased the content of macrotetrolides in chloroform as a result of forming strong hydrophobic complexes. This is especially applied to the ions of ammonium whose addition to the aqueous phase led to an increase of macrotetrolide level in chloroform up to 98.4 per cent. Addition of weak hydrochloric acid or alkaline agents resulted in marked transfer of the ionophores into the aqueous phase at the expense of hydrolysis of the antibiotic cyclic molecules. The highest hydrolysis levels were induced by potassium hydroxide, the content of the ionophores in the hydrophobic phase decreasing up to 90.6 per cent. The effect of picric acid on distribution of the macrotetrolides between water and chloroform was different and depended on its concentration.     

Effect of lincomycin and staphylococcal vaccine on the course of experimental staphylococcal sepsis

Therapeutic efficacy of lincomycin used alone and in combination with inactivated staphylococcal vaccine and the effect of these agents on synthesis of antibodies and their content in blood serum were investigated. Lincomycin was shown to inhibit septic processes in the host. After its administration the number of the pathogens in the blood and organs markedly decreased. At the same time, lincomycin lowered antibody synthesis in the lymphoid organs and the content of alpha-antitoxins in blood serum. The use of lincomycin in combination with inactivated staphylococcal vaccine promoted an increase in the number of the antibody forming cells in the spleen and lymph nodes and the content of the antibodies to the staphylococcal alpha-toxin in blood serum of the animals with staphylococcal sepsis.