CHANGE OF ACID AGGLUTINATION OPTIMUM AS INDEX OF BACTERIAL MUTATION

A distinct difference in acid agglutination optimum for Type D (bacillus of rabbit septicemia) and its mutant form, Type G, has been observed. The optimum for Type D lies between pH 3.5 and pH 3.0. This changes during mutation, the resulting Type G mutants having in general an optimum lying between pH 4.7 and pH 3.8. The constancy of the optimum for Type D is very strict, while that for Type G is slightly less so. The variation is never so great as to cause an overlapping of optima and consequent failure of differentiation. These acid agglutination optima are in the nature of physical constants for the two types and would imply a fundamental difference in the chemical constitution of the organisms. Animal passage, far from causing a reversion of the mutant Type G to the primordial Type D form, brings about a still greater instability in the presence of H ions.     

Isolation by affinity chromatography of a cholinergic proteolipid from Nucleus caudatus.

A cholinergic proteolipid fraction (i.e. a hydrophobic lipoprotein) was separated from the $\text{n. caudatus}$ of the cow, using affinity chromatography with the lipophilic gel Sephadex LH-20 and p-phenyltrimethylamonium as the active group. High affinity binding studies showed that only the specific fraction, desorbed after an acetylcholine (or acid) pulse, and corresponding to 0,72% of the proteolipids, is the one that binds the cholinergic ligands. The binding of (³H)atropine and (¹⁴C)d-tubocurarine demonstrated that there are 814 picomoles/g fresh tissue of muscarinic sites and only 76 picomoles/g of nicotinic sites. The specific radioactivity for (³H)atropine is 10,000 nmoles/g protein, suggesting a high degree of purification of the specific cholinergic proteolipid.     

UDP-Gal: <Emphasis Type="Italic">N</Emphasis>-acetylglucosamine β 1–4 galactosyltransferase expressing live attenuated parasites as vaccine for visceral leishmaniasis

As compared to cutaneous leishmaniasis, vaccination against visceral leishmaniasis (VL) has received limited attention. In this study, we demonstrate for the first time that an UDP-Galactose: N-acetylglucosamine β 1–4 galactosyltransferase (GenBank Accession No. EF159943) expressing attenuated LD clonal population (A-LD) is able to confer protection against the experimental challenge with the virulent LD AG83 parasite. A-LD was also effective in established leishmania infection. The vaccinated animals showed both cell mediated (in vitro T-cell proliferation, and DTH response) and humoral responses (Th1 type). These results demonstrate the potential of the attenuated clones as an immunotherapeutic and immunoprophylactic agent against visceral leishmaniasis.     

Kulturversuche mit Flechtenpilzen (Xanthoria parietina)

Ohne Zusammenfassung     

Linkage analysis of the murine mos proto-oncogene on chromosome 4

A linkage analysis of the murine Mos gene, which codes for the c-mos proto-oncogene, was performed in 88 backcross progeny of an interspecies cross of laboratory mice and Mus spretus. Linkage was tested for four different genes on mouse chromosome 4: Aco-1, Mup-1, b, and Ifb. The gene order (from centromere) with intervening percentage recombination is Mos-15.9 (+/- 3.9)-Aco-1-5.6 (+/- 2.4)-Mup-1-3.4 (+/- 1.9)-b-5.6 (+/- 2.4)-Ifb. These results confirm the previous assignment of Mos to chromosome 4 on the basis of segregation in somatic cell hybrids (D. Swan et al., 1982, J. Virol. 44: 752-754) and show furthermore that Mos and the Ifa/Ifb clusters are not tightly linked as a group of intronless genes, but are separated by a map distance of 30.6 +/- 4.9 recombination units. The linkage data obtained in the present study place Mos in a region compatible with the physical map (D. W. Threadgill and J. E. Womack, 1988, Genomics 3: 82-86).     

ESR evidence of superoxide radical dismutation by human ceruloplasmin

The formation of the paramagnetic complex between human ceruloplasmin and radiation produced superoxide radicals was observed by the ESR method at low temperatures. The disappearance of the complex without changes in the oxidation state of copper give the direct evidence that ceruloplasmin, the major antioxidant in serum, is able to dismutate superoxide radicals.