Population analysis of minor hemoglobin fractions. I. Hemoglobin A2]

The inhabitants of 7 isolated villages (of different nationalities) and of 5 panmictic populations were studied. Populational and segregation analyses of Hb A2 in 3036 normal and 150 heterozygous individuals for beta- and delta beta-thalassemia were carried out. The Hb A2 levels in some populations are established to deviate from the normal distribution. Bimodal dependency of the levels of Hb A2 distribution is demonstrated, which suggests the existance of heterogenous subpopulations by the Hb A2 level. The segregation analysis has revealed distinct genetic determination of Hb A2 levels. There was a good correlation between Hb A2 and Hb F values (r=-0.82).     

Characteristics of immunomodulating effect of histamine in inbred strain mice]

The activity of 5'-nucleotidase of peritoneal exudate in subcutaneous injection of histamine in a dose of 1.0-100 microliters was studied in mice of different lines (CBA, C57, B1/6, Balb/c, NFS/n, NFR/n). There were interline differences in the influence of histamine on this metabolic index.     

Characteristic properties of the complex of glycogen synthase with glycogen

The glycogen synthase I--glycogen complex isolated from rabbit skeletal muscles is stable during precipitation with trichloroacetic acid and Sepharose 2B chromatography. The complex catalyzes the synthesis (lengthening) of the alpha-1.4-glucosyl chains when endogenous or exogenous enzyme-free glycogen is used, the initial rates of this synthesis being identical. Preincubation with glycogen does not cause activation of the complex or formation of additional glycogen synthase I--polysaccharide bonds. The complex is characterized by saturation with respect to glycogen; the molar concentration ratios of the non-reducible chain and protein monomer within the complex does not exceed 100. An increase in the length of the synthesized alpha-1.4-glycosyl chains of glycogen results in a decrease of the rate of the glycogen synthase reaction in time.     

Isolation and physico-chemical properties of a protein, included in an endotoxin from Yersinia pseudotuberculosis

A major protein of the endotoxin from Yersinia pseudotuberculosis was isolated from the complex lipid A--protein by treatment with SDS and triton X-100 followed by gel-chromatography on Sephacryl S-300. Protein has apparent molecular mass 40 kDa and alanine as N-terminal amino acid residue. CD and IR spectroscopy conformational changes of the protein molecule in the process of its isolation. The thermal and pH stabilities of the protein were investigated by the methods of intrinsic fluorescence and differential scanning microcalorimetry. The isolated protein revealed two thermal transitions (at 30-35 and 50-55 degrees C), which depend on Ca2+ concentration.     

Mitochondrial DNA evolution in the genus Equus

Employing mitochondrial DNA (mtDNA) restriction-endonuclease maps as the basis of comparison, we have investigated the evolutionary affinities of the seven species generally recognized as the genus Equus. Individual species' cleavage maps contained an average of 60 cleavage sites for 16 enzymes, of which 29 were invariant for all species. Based on an average divergence rate of 2%/Myr, the variation between species supports a divergence of extant lineages from a common ancestor approximately 3.9 Myr before the present. Comparisons of cleavage maps between Equus przewalskii (Mongolian wild horse) and E. caballus (domestic horse) yielded estimates of nucleotide sequence divergence ranging from 0.27% to 0.41%. This range was due to intraspecific variation, which was noted only for E. caballus. For pairwise comparisons within this family, estimates of sequence divergence ranged from 0% (E. hemionus onager vs. E. h. kulan) to 7.8% (E. przewalskii vs. E. h. onager). Trees constructed according to the parsimony principle, on the basis of 31 phylogenetically informative restriction sites, indicate that the three extant zebra species represent a monophyletic group with E. grevyi and E. burchelli antiquorum diverging most recently. The phylogenetic relationships of E. africanus and E. hemionus remain enigmatic on the basis of the mtDNA analysis, although a recent divergence is unsupported.      

Structural studies on the immunodominant group of lipid A from lipopolysaccharide of Yersinia pseudotuberculosis.

Lipid A isolated from lipopolysaccharide of Yersinia pseudotuberculosis was used for immunization of rabbits to afford antisera to lipid A with titers of 1:640 in the passive hemolysis test. Exhaustion of immune serume with sheep erythrocytes decreased antibody titers up to 1:160. Authentic samples of 2-(DL-3-hydroxytetradecanoyl)amino-2-deoxy-D-glucose 6-phosphate, 2-tetradecanoylamino-2-deoxy-D-glucose 6-phosphate and 2-acetamido-2-deoxy-D-glucose 6-phosphate have been synthesized in order to carry out a comparative study of inhibitory activity of these compounds and lipid A using a system of lipid A and antiserum to lipid A. As a result, the immunodominant moiety of the lipid A of Y. pseudotuberculosis proved to contain a D-glucosamine residue acylated with 3-hydroxytetradecanoic acid at the amino group. The nature of the fatty acid acylating the amino group of glucosamine does not play an important role in the structure of immunodominant moiety of lipid A.     

Comparative antibiotic sensitivity of different species of staphylococci isolated from humans]

A total of 206 strains of various staphylococcal species isolated from various sources were studied with respect to their sensitivity to 18 antibiotics. The number of strains poly-resistant to the antibiotics was almost the same among Staph. aureus and Staph. epidermidis, i. e. 54.8 and 51.3 per cent respectively. The coagulase-negative and mannitol-negative variants of Staph. aureus and Staph. epidermidis possessing high biological activity (10-14 properties) were resistant to more antibiotics as compared to the low active strains.     

Cassava leaf harvesting as vegetables; a cause of vulnerability of cassava plant to cassava mosaic disease and eventual yield reduction: Ernte von cassavablättern als gemüse; eine ursache für die anfälligkeit der cassavapflanze für die cassava-mosaikkrankheit und für spätere ertragseinbußen

The consequence of harvesting young leaves of cassava as vegetable on the vulnerability of the crop to cassava mosaic disease (CMD) and on storage root yield was investigated using 30 cassava genotypes planted in IITA fields located in the humid forest (Port Harcourt?:?Onne), forest-savannah transition (Ibadan), southern guinea savannah (Mokwa) and northern guinea savannah (Zaria) agroecologies in Nigeria. Tender apical leaves and shoots of the cassava genotypes were removed from forty plants per cassava genotype with the same number of plants considered as control. Whitefly infestation, disease incidence (DI) and symptom severity (ISS) of the disease were assessed at monthly interval for six months and also at the ninth month after planting (MAP). Yield reduction due to this treatment was calculated as percentage harvest index (HI). Whitefly population fluctuated throughout the period of observation at all locations with higher population obtained generally for treated plants compared to control plants. Sprouting leaves of some treated genotypes were observed with severe mosaic symptoms, while corresponding control showed no mosaic symptoms. Contrarily, no remarkable difference was observed in Zaria between the mean ISS of treated and control cassava genotypes. There was a highly significant difference (P?<?0.01) in DI and ISS among cassava genotypes across all locations. Also, there was a highly significant interaction (P?<?0.01) in symptom severity between location (loc) and genotype, genotype and treatment (trt), loc and trt. Interaction between loc, genotypes and trt with regard to DI was highly significant at 2, 3 and 4 MAP, while with ISS, the interaction was highly significant all through the counting period. There was a positive relationship between DI and ISS on plants of genotypes 96/1039 and ISU. The percentage HI (27.4) of treated plants of genotype 95/0166 in Ibadan was remarkably lower than the value obtained for corresponding control (41.9) plants. Also, sharp distinction in% HI of treated (39.5) and control (43.8) ISU was observed in Onne with their respective ISS values as 3.7 and 3.2. Therefore, harvesting tender apical leaves and shoots of cassava as vegetables should be discouraged as it increases the severity of CMD infection in the regenerating shoots of cassava with attendant storage root yield reduction.