Efficient and reliable protoplasting, regeneration, and fusion techniques were established for the prototrophic strain Bacillus stearothermophilus NUB36. Auxotrophic mutants were isolated, and protoplast fusion was used to construct isogenic mutant strains and for chromosomal mapping. Markers were mapped using two-, three-, and four-factor crosses. The order of the markers was hom-1-thr-1-his-1...

The electric field method of gene transfer via electroporation of cell membranes is gaining importance in cellular and molecular biology. In particular the electroporation technique provides the low copy number transfection required fqr genetic studies. As demonstrated with mouse lyoma cells, with lymphoid cell lines and with plant protoplast, the electric method has appreciable advantages comp...

Intraspecific protoplast fusion, induced by polyethylene glycol and Ca2+, was carried out in various pairings between auxotrophic nystatin-sensitive, ergosterol-producing strains of Candida albicans and their nystatin-resistant, ergosterol-less mutants of different origins. Nutritionally-complemented stable heterozygous diploid hybrids were obtained, which proved to be sensitive, semi-resistant...

Double auxotrophic and morphological mutants of Trichoderma pseudokoningii Rifai were fused by anastomosis and by protoplast fusion. The recovery of recombinants from heterokaryons on different selective media and from heterokaryotic colonies indicated the occurrence of parasexual events. Prototrophic colonies growing on minimal medium produced binucleate spores, green in colour, revealing a no...