A new variety of coreopsis Californica (Compositae) Endemic to Arizona

Coreopsis californica var. newberryi, a new variety, differing from typical material ofC. californica in achene morphology, is proposed. Achene spotting in the two varieties exhibits maternal inheritance.     

A prevalent persistent global nonrandomness that distinguishes coding and non-coding eucaryotic nuclear DNA sequences

Summary Coding sequences of eucaryotic nuclear DNA were characterized by an excess of short runs and a deficit of long runs of weak and of strong hydrogen bonding bases; non-coding sequences by a deficit of short runs and an excess of long runs, in the same of purines and of pyrimidines. The conservation of these attributes across DNA sequences coding for proteins of widely different function, across widely different eucaryotic species for the same protein and across related genes that diverged a long time ago and that now show large differences in base and, if coding, amino acid sequence suggested that these attributes have survival value. It was concluded that these attributes constitute probalistic constraints on th primary structure (base sequence) of both coding and non-coding DNA.     

Electrical Properties and Ultrastructure of Mycoplasma Membranes

Mycoplasma, in particular species laidlawii and gallisepticum, are found to have a very small, low frequency conductivity as would be predicted by the dielectric model for bacteria and their apparent lack of cell wall structure. Membrane capacitance values for the two organisms are both about 0.9 μF/cm², although electron micrographs show that the membrane of M. gallisepticum is 20-40 A thicker than that of M. laidlawii.     

Passive Electrical Properties of Microorganisms: V. Low-Frequency Dielectric Dispersion of Bacteria

Very high dielectric constants have been observed for bacteria at low frequencies. High dielectric constants such as these can be explained by a theory which has been developed for the low-frequency dielectric dispersion of porous charged particles and which has been tested successfully through measurements with ion exchange resins. The bacterial cell wall is electrically similar to an ion exchange resin. Observations show that the theory provides a quantitative explanation for the low-frequency dielectric dispersion of bacteria.     

The Relationship between Cell Membrane Potassium Ion Transport and Glycolysis : The effect of ethacrynic acid

Cell membrane transport of K⁺ stimulates the rate of glycolysis in Ehrlich ascites tumor cells. A study of the characteristics of this relationship indicates that the stimulation occurs under anaerobic as well as under aerobic conditions. The data suggest that glycolysis is stimulated by a K⁺ transport mechanism that is coupled to Na⁺ transport because the effect is blunted or abolished when the principal intracellular ion is lithium or choline. This stimulus to glycolysis is blocked by ouabain and ethacrynic acid, agents that have been shown to inhibit monovalent cation transport in erythrocytes. In contrast to the action of ouabain, glycolysis is inhibited by ethacrynic acid in Ehrlich ascites tumor cells in the absence of cell membrane K⁺ transport. In studies with ghost-free hemolysates of human erythrocytes and with cytosol prepared from Ehrlich ascites tumor cells, ethacrynic acid significantly blocks lactate formation from fructose diphosphate demonstrating the direct inhibitory effect of this agent on one or more enzymes of the Embden-Meyerhof pathway. Since ethacrynic acid has no influence on lactate formation in intact erythrocytes utilizing an endogenous substrate, the presumptive site of inhibition is proximal to the 3-phosphoglycerate level.     

Electrophoretic separation of multiple bands with beta-glucuronidase activity in human sera

An electrophoretic procedure is described which resulted in the separation of up to four bands with beta-glucuronidase activity in human sera. Initial screening of a small sample of individuals revealed persons with two, three, and four bands.Supported by Special Project Grant Number 414 of the Children's Bureau, U.S. Department of Health, Education and Welfare.