BACKGROUND One of the greatest challenges in occupational dermatology is the identification of chemical substances used by patients in their work in order to determine their allergenic potential. Numerous techniques have been described for the identification of allergenic compounds. These tests must be sensitive, specific, and safe. We describe a study to detect the presence of paraphenylenedia...

The bacterial cytoplasmic membrane is a major inhibitory target for antimicrobial compounds. Commonly, although not exclusively, these compounds unfold their antimicrobial activity by disrupting the essential barrier function of the cell membrane. As a consequence, membrane permeability assays are central for mode of action studies analysing membrane-targeting antimicrobial compounds. The most ...

Physicochemical properties of the plasma membrane have been shown to play an important role in cellular functionality. Among those properties, the molecular order of the lipids, or the lipid packing, is of high importance. Changes in lipid packing are believed to compartmentalize cellular signaling by initiating coalescence and conformational changes of proteins. A common way to infer membrane ...

Martin D. Bootman,1,2,5 Katja Rietdorf,3 Tony Collins,4 Simon Walker,1 and Michael Sanderson3 Babraham Institute, Babraham, Cambridge, CB22 3AT, United Kingdom; Department of Life, Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, United Kingdom; Department of Microbiology and Physiology Systems, University of Massachusetts Medical School, Worcester, Massac...

We carried out experiments to monitor optically the generation and spread of action potentials and subthreshold potentials in the processes of individual neurons in ganglia of the snail, Helix aspersa. The neurons were selectively stained by intracellular pressure injection of voltage-sensitive dyes. Optical signals were detected by a system for fast, multiple-site optical monitoring, utilizing...

We consider the physicochemical basis for enzyme-induced staining of cell membranes by fluorescent voltage-sensitive dyes, a method that may lead to selective labeling of genetically encoded nerve cells in brain for studies of neuronal signal processing. The approach relies on the induction of membrane binding by enzymatic conversion of a water-soluble precursor dye. We synthesized an amphiphil...

Calcium imaging of neural network function has been limited by the extent of tissue labeled or the time taken for labeling. We now describe the use of electroporation-an established technique for transfecting cells with genes-to load neurons with calcium-sensitive dyes in the isolated spinal cord of the neonatal mouse in vitro. The dyes were injected subdurally, intravascularly, or into the cen...

Studies of the spatio-temporal distribution of inhibitory postsynaptic potentials (IPSPs) in a neuron have been limited by the spatial information that can be obtained by electrode recordings. We describe a method that overcomes these limitations by imaging IPSPs with voltage-sensitive dyes. CA1 hippocampal pyramidal neurons from brain slices were loaded with the voltage-sensitive dye JPW-1114 ...

Potentiometric sensors require the implementation of conducting wires for signal transduction, but this is impractical for the readout of individual nanoparticles. It is here demonstrated for the first time that the potentiometric response of ion-selective nanospheres can be observed with voltage-sensitive dyes, thereby converting nanoscale electrochemical signals into an optical readout. No re...