Paul Arenz Lemke

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A nontoxigenic isolate of Aspergillus flavus (NRRL 5565) contains a viral genome consisting of 3 double-stranded RNA (ds-RNA) components with molecular weights of approximately 3 kb each. It thus shares a characteristical feature with a virus occuring in strains of Penicillium chrysogenum. Application of known inhibitors of doublestranded RNA virus(More)
Protoplasts of the ectomycorrhizal fungus, Laccaria laccata, were transformed at frequencies of 5–50 transformants/μg DNA. Transformation was based on positive selection for resistance to hygromycin B (HmB) using the Escherichia coli aminocyclitol phosphotransferase (aph) gene bracketed by an Aspergillus nidulans glyceraldehyde-3-phosphate dehydrogenase(More)
The existece of plasmid like DNA was demonstrated in senescent mycelia of Podospora anserina (strain s) by biophysical and electronmicroscopic methods. According to their contour length of about 1.4 and 2.7 μm respectively the molecular weight for the monomer is in the range of 3·106.
Double-stranded ribonucleic acid present in virus-infected mushrooms of Agaricus bisporus has been resolved through polyacrylamide gel electrophoresis into six molecular-weight forms. Identification of these six double-stranded ribonucleic acids in mushrooms by this procedure has proven to be a useful and diagnostic method for viral infection in the(More)
Conditions for the formation of protoplasts from selected species of ectomycorrhizal fungi are described. The age of the fungal culture and extent of incubation in a lytic enzyme mixture are critical factors for efficient formation of protoplasts. There is a correlation between the distribution of nuclei in hyphal fragments and protoplasts and the frequency(More)
A transformation system employing selectable resistance to hygromycin B has been developed for the mushroom-forming fungus, Pleurotus ostreatus. Vector pAN7-1, a commonly used non-replicative vector for integrative transformation in fungi, yielded 5–46 resistant colonies per μg of DNA per 107 viable protoplasts. Southern blot analysis of certain(More)
 An Aspergillus nidulans strain, auxotrophic for pyrimidine, was transformed to prototrophy by means of microprojectile bombardment. The transformation frequency was somewhat lower than conventional polyethyleneglycol-mediated transformation of protoplasts. However, the percentage of stable transformants was considerably higher with the biolistic approach.(More)
A convenient miniassay for aflatoxin has been developed for cultures ofAspergillus flavus andA. parasiticus grown for 3–10 days in 10 ml of a coconut extract medium. The sensitivity of the assay, as measured by photofluorometry (365 nm maximum excitation; 445 nm maximum emission), is of the order of 0.01 μM (3.12 ng/ml) for aflatoxin B1 dissolved in aqueous(More)
The genetic investigation of fungi has been extended substantially by DNA-mediated transformation, providing a supplement to more conventional genetic approaches based upon sexual and parasexual processes. Initial transformation studies with the yeastSaccharomyces cerevisiae provided the model for transformation systems in other fungi with regard to(More)
Replicative plasmids pP01 and pP02, recovered from Pleurotus ostreatus transformants, contain an insert of bacteriophage origin. These plasmids have been amplified by the polymerase chain reaction (PCR) and have been shown to represent a low-grade component in the initial preparation of the vector pAN7-1. The pP01 and pP02 plasmids share an insert (P01A) of(More)