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Full-Text Articles in Life Sciences
The Voltage Sensor Of Excitation-Contraction Coupling In Skeletal Muscle. Ion Dependence And Selectivity, Gonzalo Pizarro, Robert H. Fitts, Ismael Uribe, Eduardo Rios
The Voltage Sensor Of Excitation-Contraction Coupling In Skeletal Muscle. Ion Dependence And Selectivity, Gonzalo Pizarro, Robert H. Fitts, Ismael Uribe, Eduardo Rios
Biological Sciences Faculty Research and Publications
Manifestations of excitation-contraction (EC) coupling of skeletal muscle were studied in the presence of metal ions of the alkaline and alkaline-earth groups in the extracellular medium. Single cut fibers of frog skeletal muscle were voltage clamped in a double Vaseline gap apparatus, and intramembrane charge movement and myoplasmic Ca2+ transients were simultaneously measured. In metal-free extracellular media both charge movement of the charge 1 type and Ca transients were suppressed. Under metal-free conditions the nonlinear charge distribution was the same in depolarized (holding potential of 0 mV) and normally polarized fibers (holding potentials between -80 and -90 mV). The manifestations …
Molecular Analysis Of N6-Methyladenine Patterns In Tetrahymena Thermophila Nuclear Dna, Elizabeth E. Capowski, John M. Wells, Gail Singer Harrison, Kathleen M. Karrer
Molecular Analysis Of N6-Methyladenine Patterns In Tetrahymena Thermophila Nuclear Dna, Elizabeth E. Capowski, John M. Wells, Gail Singer Harrison, Kathleen M. Karrer
Biological Sciences Faculty Research and Publications
We have cloned two DNA fragments containing 5'-GATC-3' sites at which the adenine is methylated in the macronucleus of the ciliate Tetrahymena thermophila. Using these cloned fragments as molecular probes, we analyzed the maintenance of methylation patterns at two partially and two uniformly methylated sites. Our results suggest that a semiconservative copying model for maintenance of methylation is not sufficient to account for the methylation patterns we found during somatic growth of Tetrahymena. Although we detected hemimethylated molecules in macronuclear DNA, they were present in both replicating and nonreplicating DNA. In addition, we observed that a complex methylation …
Methylation Of Replicating And Nonreplicating Dna In The Ciliate Tetrahymena Thermophila, Gail Singer Harrison, Kathleen M. Karrer
Methylation Of Replicating And Nonreplicating Dna In The Ciliate Tetrahymena Thermophila, Gail Singer Harrison, Kathleen M. Karrer
Biological Sciences Faculty Research and Publications
Methylation of adenine in replicating and nonreplicating DNA of the ciliate Tetrahymena thermophila was examined. In growing cells, 87% of the methylation occurred on the newly replicated daughter strand, but methylation was also detectable on the parental strand. Methylation of nonreplicating DNA from starved cells was demonstrated.