The Electrophoretic Velocity of Human Red Cells, of Their Ghosts and Mechanically Produced Fragments, and of Certain Lipid Complexes

Ghosts prepared in CO₂-saturated water from unwashed human red cells can be fragmented mechanically, but ghosts from thrice washed cells cannot. If the ghosts are prepared by freezing and thawing, this difference is not observed. The electrophoretic velocity varies also with the way in which the ghosts are prepared. The pH-mobility dependence of washed red cells flatten off to a plateau at pH 9, and the electrophoretic velocity is zero at about pH 2. Ghosts prepared by freezing and thawing have almost the same pH-mobility dependence, but if the ghosts are prepared in CO₂-saturated hyptonic saline, the mobility at pH 9.4 is 0.75 times that of washed cells. Fragments of ghosts of unwashed red cells have a smaller mobility than that of the red cells. Trypsin reduces the mobility of washed red cells and of ghosts. Sols of lipid complexes (lecithin, cephalin, and lipositol), at varying pH's, have a mobility 1.2 times that of the washed red cell. The pH-mobility relation is otherwise similar. These complexes can be coated with dextran and trypsin.     

Rapid Differentiation Between Nocardia and Streptomyces by Paper Chromatography of Whole-Cell Hydrolysates

Whole-cell hydrolysates were prepared from 58 strains of nocardiae and streptomycetes. Strains morphologically intermediate between the two genera and morphological variants of the same strains were included. Paper chromatograms made from the whole-cell hydrolysates clearly demonstrated meso-diaminopimelic acid as a major constituent of cultures of Nocardia spp., and LL-diaminopimelic acid as a major constituent of cultures of Streptomyces spp. In cultures of ten strains of N. madurae and of three of N. pelletieri, meso-diaminopimelic acid predominated, thereby supporting the assignment of these species to the genus Nocardia.     

Genetic analysis of streptomycin-resistance and-dependence inChlamydomonas

Summary Three non-chromosomal and two chromosomal genes which influence resistance to streptomycin are described. Each of the non-chromosomal factors,sr-500,sr-1500, andsd, exhibits uniparental inheritance, with all progeny receiving the factor when it is carried by the parent of mating-typeplus, and none when it is carried by the mating-typeminus parent. The streptomycin-dependence factor,sd, shows zygotic dominance when contributed by the mating-typeplus parent, but not when coming from the mating-typeminus parent, indicating that the uniparental transmission results from events occurring within the zygote early in maturation and well before meiosis. The chromosomal geneA interacts both with chromosomal and non-chromosomal genes at the biochemical level, but does not alter their patterns of inheritance.With 1 Figure in the TextThis paper is dedicated to ProfessorL. C. Dunn in gratitude to him as teacher and advisor, on the occasion of his retirement.This work was supported by grants from the U.S. Public Health Service and the National Science Foundation. The generosity and interest of ProfessorFrancis J. Ryan in providing laboratory space is gratefully acknowledged, as is the technical assistance of MissFran Yablonsky.     

Effects of carbon–dioxide-bicarbonate mixtures on oxidative phosphorylation by cauliflower mitochondria

1. Carbon dioxide-bicarbonate mixtures markedly inhibited oxidation and phosphorylation rates of mitochondria prepared from cauliflower. Inhibition occurred with succinate, malate, citrate, isocitrate and NADH as substrates. 2. Indophenol-reductase systems with malate, succinate, isocitrate and NADH as substrates were inhibited by 5% and 15% carbon dioxide. Cytochrome c oxidase was not inhibited by 15% carbon dioxide.     

Uptake and acylation of 2-acyl-lysophospholipids by Escherichia coli.

The efficiency of extracellular 2-acyl-lysophospholipid incorporation into Escherichia coli membranes and the acyl donor utilized to acylate the 2-acyl-lysophospholipid was determined. Exogenous 2-acyl-lysophospholipids were acylated via the acyl-acyl carrier protein synthetase/2-acylglycerophosphoethanolamine acyltransferase pathway. The maximum extent of 2-acyl-lysophospholipid incorporation into the membrane was approximately 2.5% of the normal phospholipid biosynthetic rate.     

Use of lacZ fusions to measure in vivo expression of the first three genes of the Escherichia coli unc operon.

We have constructed in-frame lacZ protein fusions to the first three genes of the Escherichia coli unc operon, which codes for the subunits of the proton-translocating ATPase. We have used these constructions to measure the relative in vivo expression of these genes. The second and third genes, uncB and uncE, which code for the a and c subunits of the F0 sector, were expressed at relative levels of approximately 1:10, although the measured expression of uncB depended upon how much of the gene was fused to lacZ. These rates compared favorably with the relative numbers of a and c subunits (a1:c10) in the purified F1F0 complex. The in vivo expression of uncI, the first gene of the operon, was very low, at best 10 to 20 times less than the expression of uncB.