Obtaining monoclonal antibodies to Bordetella pertussis antigens

The immunization of mice with the protein fraction of B. pertussis strain 305 has made it possible to obtain hybridomas producing monoclonal antibodies to B. pertussis antigens. Ascitic fluids containing monoclonal antibodies react in the ELISA in high titers and actively agglutinate B. pertussis strains 305 and 475.     

Further results on the survival of a gene represented in a founder population

This paper is concerned with gene survival in a population which may increase without density dependence according to a generalization of the Moran model for haploid individuals. A selective advantage to one allele and the possibility of differential reproductive rates are allowed. Simple conditions are given for ultimate homozygosity to be certain and for the possibility of ultimate polymorphism. The results complement and extend those of Heyde (1981, 1982).     

Purine salvage as metabolite and energy saving mechanism in Camelus dromedarius: the recovery of guanine

The preservation of purine ring as purine bases appears to be a common feature of camel liver. Hepatic guanine appears to be actively converted into GMP in the camel rather than further degraded. The limiting step of guanine degradation appears to be the lack of hepatic guanase activity. Higher purine bases over uric acid ratios were found in camel urine with respect to those of zebu.     

Conformational differences between linear alpha (2----8)-linked homosialooligosaccharides and the epitope of the group B meningococcal polysaccharide

The alpha-(2----8)-linked sialic acid oligosaccharides (NeuAc)n exhibit an unusual degree of heterogeneity in the conformation of their linkages. This was diagnosed by observation in their 13C NMR spectra of an equivalent and unique heterogeneity in the chemical shifts of their anomeric carbons and subsequently confirmed by more comprehensive 1H and 13C NMR studies. In these studies both one-dimensional and two-dimensional experiments were carried out on the trisaccharide (NeuAc)3 and colominic acid. In addition to the unambiguous assignment of the signals in the spectra, these experiments demonstrated that both linkages of (NeuAc)3 differed in conformation from each other and from the inner linkages of colominic acid. The NMR data indicate that these conformational differences extend to both terminal disaccharides of oligosaccharides larger than (NeuAc)5, a result that has considerable physical and biological significance. In the context of the group B meningococcal polysaccharide, it provides an explanation for the conformational epitope of the group B meningococcal polysaccharide, which was proposed on the evidence that (NeuAc)10, larger than the optimum size of an antibody site, was the smallest oligosaccharide able to bind to group B polysaccharide specific antibodies. Because the two terminal disaccharides of (NeuAc)10 differ in conformation to its inner residues, the immunologically functional part of (NeuAc)10 resides in its inner six residues. This number of residues is now consistent with the maximum size of an antibody site.     

Gentamicin and amikacin repress the growth of Plasmodium falciparum in culture, probably by inhibiting a parasite acid phospholipase

Human erythrocytes were loaded with either gentamicin or amikacin and subsequently infected with the human malarial parasite Plasmodium falciparum and grown in culture. Parasite invasion of erythrocytes was unaffected by the drugs, but subsequent development was retarded. The digestion of host cell cytosol in ring-stage parasites was inhibited by the drugs. A substantial acid, Ca2+-independent phospholipase activity could be monitored in parasite cytosol and was found to be inhibited by the drugs. These results imply that phospholipases are involved in the feeding mechanism of the parasite and that gentamicin and amikacin exert their inhibitory activity by affecting these enzymes.     

Phenotype frequencies of vitamin D binding protein (Gc) and of posttransferrin-2 (Ptf-2) in Belgian cattle breeds*

The vitamin D binding protein (Gc) and posttransferrin-2 (Ptf-2) phenotypes have been determined in a number of Belgian cattle breeds. A very slow migrating variant of the Gc protein — Gc C — has been found in White and Red East Flemish breed. This variant was absent from the other breeds studied. This slow variant was identified as a vitamin D binding protein by autoradiography. The Gc C protein was shown to be controlled by a codominant autosomal allele Gc C at the Gclocus. The Gc C protein is probably identical with a fraction previously described in buffalo and an Italian cattle breed. The allele frequencies for the Gc and Pft-2 systems are reported for several Belgian breeds of cattle.     

Tunicamycin-resistant mutants of Bacillus amyloliquefaciens are deficient in amylase, protease and penicillinase synthesis and have altered sensitivity to antibiotics and autolysis

Mutants of Bacillus amyloliquefaciens resistant to at least 10 micrograms/ml of tunicamycin were isolated and shown to be pleiotropic. The mutants were more resistant to streptomycin, chloramphenicol, kanamycin and neomycin than was the parent strain but less resistant to penicillin G and tetracycline. They were more autolytic, presumably due to an altered cell wall. The mutants produced reduced levels of amylase, penicillinase and both metal and serine protease besides having an enhanced sporulation frequency and being more motile.