Mechanisms of carbacholine and GABA action on resting membrane potential and Na+/K+-ATPase of Lumbricus terrestris body wall muscles.

This work was aimed to identify the action of several ion channel and pump inhibitors as well as nicotinic, GABAergic, purinergic and serotoninergic drugs on the resting membrane potential (RMP) and assess the role of cholinergic and GABAergic sensitivity in earthworm muscle electrogenesis. The nicotinic agonists acetylcholine (ACh), carbacholine (CCh) and nicotine depolarize the RMP at concentrations of 5 μM and higher. The nicotinic antagonists (+)tubocurarine, α-bungarotoxin, muscarinic antagonists atropine and hexamethonium do not remove or prevent the CCh-induced depolarization.

Controlling the enzymatic activity of a restriction enzyme by light.

For many applications it would be desirable to be able to control the activity of proteins by using an external signal. In the present study, we have explored the possibility of modulating the activity of a restriction enzyme with light. By cross-linking two suitably located cysteine residues with a bifunctional azobenzene derivative, which can adopt a cis- or trans-configuration when illuminated by UV or blue light, respectively, enzymatic activity can be controlled in a reversible manner.

A convenient solid-phase method for the synthesis of novel oligonucleotide-folate conjugates.

We describe the preparation of two batches of a polymer support for the incorporation of folic acid into oligonucleotides. The method permits the regioselective attachment of a target nucleic acid sequence through its 3'-end to either the alpha-or gamma-carboxyl group of L-glutamic acid, respectively. The supports have been tested in solid-phase synthesis of oligonucleotide-folate conjugates for cell delivery studies.

Detection of glycosylase, endonuclease and methyltransferase enzyme activities using immobilized oligonucleotides.

A novel rapid assay for detection of DNA glycosylase, restriction endonuclease, and DNA methyltransferase enzyme activities is presented. The assay is based on enzyme-dependent label release (in case of glycosylase and endonuclease), or non-release (in case of methyltransferase) into solution from end-labeled DNA immobilized on solid support (CPG or Tenta Gel S-NH2). The assay has been validated for monitoring activity of repair enzyme uracil-DNA glycosylase, restriction endonucleases SsoII, MvaI and EcoRII and (cytosine-5)-DNA methyltransferase SsoII.