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Full-Text Articles in Life Sciences

Detergent Extraction Of A Presumptive Gating Component From The Voltage-Dependent Sodium Channel, W J. Culp, D T. Mckenzie Nov 1981

Detergent Extraction Of A Presumptive Gating Component From The Voltage-Dependent Sodium Channel, W J. Culp, D T. Mckenzie

Dartmouth Scholarship

A physiologically characterized radiolabeled neurotoxin complex obtained from venom of the scorpion Leiurus quinquestriatus has been used to identify detergent-solubilized presumptive sodium channel components in sucrose gradients. This toxin-binding component is found in extracts prepared from three sources of excitable membrane but appears to be absent from similar extracts prepared from nonexcitable membrane or from Torpedo californica membrane. Procedures that destroy the physiological activity of the Leiurus neurotoxin lead to a corresponding loss of toxin binding to the putative sodium channel component. The major component recognized by the Leiurus toxin sediments at 6.5 S. Scatchard analysis of quantitative binding experiments …


Selection And Characterization Of Cole1 Plasmid Mutants That Exhibit Altered Stability And Replication., Joseph Inselburg Sep 1981

Selection And Characterization Of Cole1 Plasmid Mutants That Exhibit Altered Stability And Replication., Joseph Inselburg

Dartmouth Scholarship

This report describes a method for isolating mutants of plasmid ColE1 that exhibit unstable maintenance and altered replication characteristics. It also describes the initial characterization of four mutants isolated by that method. A chimeric plasmid, pHSG124, containing a ColE1 derivative and a temperature-sensitive replication derivative of pSC101 was mutagenized in vitro, using hydroxylamine. By adjusting the growth conditions of transformants containing the mutagenized chimeric deoxyribonucleic acid, it was possible to rapidly screen colonies and identify those that had a high probability of carrying ColE1 mutants that exhibit unstable maintenance. Of those mutants, some exhibited altered copy number or accumulated catenated …


Sunbathing Vermilion-Crowned Flycatchers Repulse Mates, Lawrence Kilham Mar 1981

Sunbathing Vermilion-Crowned Flycatchers Repulse Mates, Lawrence Kilham

Dartmouth Scholarship

Vermilion-crowned Flycatchers (Myiozetetes similis, formerly called Social Flycatchers) remain paired the year around (Skutch 1960). I was watching the members of a pair foraging in close association along the bank of a pond (near Escuintla in the Pacific lowlands of Guatemala) on 29 December 1976, when the two came to a patch of relatively bare earth 1-2 m in extent. This was late in the morning of a hot, sunny day. One of them immediately sprawled belly to the earth, with wings and tail widely spread and head back in the sunbathing posture of a passerine (Hauser 1957). When the …


The Isolation Of Ecdysterone Inducible Genes By Hybridization Subtraction Chromatography, Michael P. Vitek, Susan G. Kreissman, Robert H. Gross Mar 1981

The Isolation Of Ecdysterone Inducible Genes By Hybridization Subtraction Chromatography, Michael P. Vitek, Susan G. Kreissman, Robert H. Gross

Dartmouth Scholarship

We have developed a procedure for selectively enriching a mRNA population for inducible sequences. Other than the induced mRNA species, the population of mRNA in control cells is approximately the same as the mRNA population in induced cells. Cytoplasmic mRNA from control cells is bound to oligo (dT)-cellulose and used as a template for reverse transcriptase, the oligo (dT) serving as a primer. After removing the template mRNAs, the cDNA-cellulose column is used to hybridize a population of mRNAs from induced cells. The non-hybridized poly A + RNAs are greatly enriched in the inducible sequences. We have used this technique …