Sweat Chlorides in Salt-Deprived Cystic Fibrosis Heterozygotes

Sweat chlorides of 10 sets of parents of children with cystic fibrosis and 11 controls were studied in an attempt to develop a test for the diagnosis of cystic fibrosis heterozygotes by subjecting both the parents and controls to a low sodium diet and comparing sweat chloride values as the diet progressed. It was hoped that the sweat chloride levels of the parents, the heterozygotes, would remain stationary throughout the diet, since their children, the homozygotes, reveal this finding under similar conditions of salt deprivation. The sweat chloride levels of the controls, because of effects of aldosterone, were expected to decrease steadily from the commencement of the diet to its termination.A decrease in sweat chloride values of similar magnitude was found in both parents and controls as the diet continued. It is concluded that the study of sweat electrolyte levels in salt-deprived subjects is of no value in the diagnosis of cystic fibrosis heterozygotes.     

Antioxidant Activity of 5-Hydroxytryptophan, 5-Hydroxyindole, and Dopa Against Microsomal Lipid Peroxidation and Its Dependence on Vitamin E

The antioxidant capacity of 5-hydroxy-tryptophan. 5-hydroxy-indole. and DOPA (3,4-dihydroxy-phenyI-alanine) was tested in the Fe-induced lipid peroxidation of liver microsomes of normal- and vitamin E-deficient rats, using ascorbate as a reductant. Lipid peroxidation was monitored as low-level chemilu-minescence, indicative of generation of electronically-excited states arising from the recombination of secondary lipid peroxyl radicals.     

N-cyanoimidazole and diimidazole imine: water-soluble condensing agents for the formation of the phosphodiester bond

The reaction of BrCN with imidazole results in the formation of N-cyanoimidazole and diimidazole imine. These compounds were shown to be useful condensing agents for the formation of the phosphodiester bound in aqueous solution.     

Combined in-beam electron impact-B/E-linked scan mass spectrometry of oxazoline derivatives for the structure determination of long-chain unsaturated fatty acids

Long-chain unsaturated fatty acids (UFA) having up to six double bonds are derivatized to 2-substituted 4,4-dimethyloxazolines (DMOX) and then analyzed by combined in-beam electron impact (IBEI)-B/E-linked scan mass spectrometry. This technique provides highly characteristic mass spectra and may serve as an auxiliary means for direct structure determination of individual UFA in mixtures.     

Classical plant taxonomic ambiguities extend to the molecular level

Summary The molecular evolution of cytochrome c from angiosperms is compared to that from vertebrates. On the basis of a cladistic analysis from 26 plant species, compared to that from 27 vertebrate species, we find that although the vertebrate sequences yield reasonably well-defined minimal trees that are congruent with the biological tree, the plant sequences yield multiple minimal trees that are not only highly incongruent with each other, but none of which is congruent with any reasonably biological tree. That is, the plant sequence set is much more homoplastic than that of the animal. However, as judged by the relative rate test, the extent of divergence, and degree of functional constraint, cytochrome c evolution in plants does not appear to differ from that of vertebrates.     

Evaluation of a method to measure conjugal transfer of recombinant DNA in soil slurries

Release of recombinant microbes into the environment necessitates an evaluation of their ability to transfer genetic material. The present report evaluates a method to detect conjugal DNA plasmid transfer in soil slurries under various environmental conditions. DonorPseudomonas cepacia containing pR388::Tn1721 andP. cepacia recipient cultures were coincubated in soil slurries containing autoclaved or natural soil and treated with one or more of 14 experimental conditions. Conjugal mating frequency (transconjugants per initial donor) ranged from 4.8×10^–1 to 1.9×10^–7. Highest numbers of transconjugants, 1.5×10⁷ colony forming units/ml soil slurry, were observed following incubation at 35°C with an enriched nutrient supplement added to the soil. Low numbers of transconjugants, 10³ colony forming units/ml soil slurry, were observed when mating pairs were subjected to low nutrient or pH stress even though initial donor and recipient populations were maintained at high levels. This test system provides a simple way to estimate effects of changing environmental factors on plasmid transfer rates and on the survival of recombinant microorganisms. By use of soil collected from sites proposed to receive genetically engineered microorganisms, preliminary risk assessments can be obtained regarding the potential for gene transfer and microorganism survival with this soil slurry test system.