Rhythmic light-sensitive movements of the leaflets of Samanea saman depend upon ion fluxes across the plasma membrane of extensor and flexor cells in opposing regions of the leaf-movement organ (pulvinus). We have isolated protoplasts from the extensor and flexor regions of S. saman pulvini and have examined the effects of brief 30-second exposures to white, blue, or red light on the relative m...

Symbiotic dinitrogen fixation of legume nodules is fuelled by phloem-imported carbohydrates. These have to pass several cell layers to reach cells infected with Rhizobium bacteroids. It is unclear whether apoplastic steps are involved in carbohyd-rate translocation within the nodule. Protoplasts were isolated from the infected and uninfected cells of the central tissue of Vicia faba nodules usi...

Cells of the osmotolerant yeast Saccharomyces rouxii were transformed to protoplasts in good yield (85%) by digesting cell walls with snail-gut enzyme in the presence of 10 mM dithioerythritol, 0.1 M sodium phosphate buffer (pH 6.8), and 2.0 M KCl. The requirement for 2.0 M KCl compares with that for S. bisporus var. mellis (another osmotolerant species) and contrasts with the 0.3 to 0.8 M KCl ...

A simple procedure for the preparation of plant cell protoplasts is described. The leaf is first treated with pectinase under conditions that do not liberate cells; cellulase is then used to release protoplasts. The yields are comparable to those obtained by methods that entail the prior preparation of free cells. The method is of general application but is particularly useful with tissues that...

Bacterial protoplasts, released from confinement within the rigid wall of whole cells, imbibe water, swell, and burst unless their suspending medium contains high concentrations of solutes which have difficulty crossing the osmotic barrier in the protoplast surface membrane (C. Weibull, Exptl. Cell Res. 9:139, 1955; P. Mitchell and J. Moyle, J. Gen. Microbiol. 20:434, 1959). Hence, protoplast p...

When protoplasts derived from sporulating cells of Bacillus subtilis were fused by exposure to polyethylene glycol (PEG) and fixed immediately thereafter, protoplasts with two enclosed prespores could be seen by electron microscope. The number of fusion events was greatly increased, and multiply fused protoplasts appeared, when the PEG-treated suspension was diluted in hypertonic broth and rein...

Preparatory experiments for the IML-1 mission using plant protoplasts, were flown on a 14-day flight on Biokosmos 9 in September 1989. Thirty-six hours before launch of the biosatellite, protoplasts were isolated from hypocotyl cells of rapeseed (Brassica napus) and suspension cultures of carrot (Daucus carota). Ultrastructural and fluorescence analysis of cell aggregates from these protoplas...

Protoplasts isolated from root cap cells of maize were shown to secrete fucose-rich polysaccharides and were used in a patch–clamp study to monitor changes in whole-cell capacitance. Ca 2 1 was required for exocytosis, which was measured as an increase in cell capacitance during intracellular dialysis with Ca 2 1 buffers via the patch pipette. Exocytosis was stimulated significantly by small in...

AUXIN RESPONSE FACTOR7 (ARF7) is one of five ARF transcriptional activators in Arabidopsis thaliana that is proposed to regulate auxin-responsive expression of genes containing TGTCTC auxin response elements in their promoters. An Arabidopsis mutant (nonphototropic hypocotyl4-1[nph4-1]) that is a null for ARF7 showed strongly reduced expression of integrated auxin-responsive reporter genes and ...

When protoplasts of the opportunistic fungal pathogen Aspergillus fumigatus were treated with low but toxic levels of hydrogen peroxide (0.1 mM) or amphotericin B (0.5 microg ml(-1)), loss of cell viability and death were associated with a number of phenotypic changes characteristic of apoptosis. The percentage of protoplasts staining positive with annexin V-FITC, an indicator of the externaliz...