A protocol for the generation of high yields of viable protoplasts has been developed for several highly branched (colonial) strains of the Quorn® myco-protein fungus, Fusarium graminearum A3/5. Driselase was found to produce higher protoplast yields (ca 109 g−1 wet weight) than the other lytic enzymes tested (Glucanex, Novozyme, β-glucuronidase, Sigma lytic enzyme, or ICN lytic enzyme), although yields differed for the various strains. Protoplast regeneration frequencies of 25–50% were observed when glucose (1·0 M) or sucrose (1·0 M) was used as the osmotic stabilizer. A highly branched strain of F. graminearum CC1-5, which grows better in submerged culture than the more sparsely branched wild-type strain (A3/5) was transformed using the hygromycin B resistance plasmid pAN7-1.

The formal taxonomy of the new family Myzocytiopsidaceae, with three new genera Myzocytiopsis, Chlamydomyzium and Syzygangia, is presented. The family also includes Gonimochaete.

Four isolates of Myzocytiopsidales infecting Rhabditis nematodes, Distylae rotifers and nematode eggs, are described. Some of these, and other species of Myzocytiopsidales, were obtained in pure culture for the first time. Reinfection of host organisms from pure culture, fulfilling Koch's postulates was achieved for all species in axenic culture.