We describe a general, simple and inexpensive method for the isolation of DNA from filamentous fungi. Starting from freeze‐dried mycelium 01–015% by weight can be isolated as high molecular weight DNA suitable for restriction and ligation in 2 h. The preparation can be done in Eppendorf tubes and allows the processing of many samples in parallel. We have used the method with the basidiomycetes Phanerochaete chrysosporium, Coprinus cinereus and the ascomycete Aspergillus nidulans and others have used it with Trichoderma reesei, Aspergillus niger and for the isolation of DNA from tomato plants.

Some of a set of independently arising Tol- (non toluate-utilising) derivatives of Pseudomonas putida mt-2 have lost the unique plasmid present in the parent strain. In others this plasmid has suffered a deletion of a specific region of about 27 Md.

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A physiological and molecular biological study was made of the control of methylenomycin biosynthesis by Streptomyces coelicolor A3(2). A simple and reliable assay for this antibiotic was developed. Conditions that permit the synthesis of methylenomycin by S. coelicolor cultures grown in defined medium were elucidated: a readily assimilated carbon and nitrogen source is required. Under these conditions methylenomycin is produced late in the growth phase, at the time of transition from exponential to linear growth. Provided that the phosphate concentration in the medium is kept high, there is synthesis of methylenomycin but not of the other secondary metabolites that this strain can produce. These conditions were used to study the transcription of the methylenomycin gene cluster during the transition from primary to secondary metabolism. The biosynthetic genes of at least one of the mmy transcription units appear to be transcribed before the mmr resistance determinant. The possibility that methylenomycin induces the transcription of mmr is discussed.

The genome of Phanerochaete chrysosporium strain ME446 contains multiple, non-allelic, cellobiohydrolase I (CBHI)-like sequences, at least two of which are expressed in a cellulose-dependent manner. Each of the expressed genes contains two identically positioned introns within its coding region. The lengths and sequences of these introns are different and one is not excised from all transcripts, raising the possibility that subtly different protein products may be expressed from a common gene. Introns are also present upstream of both genes but these differ in number and position, as well as sequence and length. Endoglucanase-like sequences could not be identified and it is suggested that variant CBHI-like proteins may provide endoglucanase activity in this fungus.

Rewired 5 April IY84; rvcised 4 Jurre 1984) A sedimentation chamber and Andersen sampler were used to isolate a range of actinomycetes on selective and non-selective media. The Occurrence of different actinomycete groups in natural substrates was compared and strains were screened for the ability to degrade ball-milled straw or to grow on lignin-related phenolic compounds. Evidence for ligninolytic activity in representatives of several genera was obtained by assaying IJCO2 evolution from [ 'Tlligninlabelled wheat lignocellulose. Most of the straw-degrading isolates were assigned to the genera Thvrmumumspora and Mic.rontorwspora, but only representatives of the latter were found to be active against [lJC]lignin. Of the non-straw-degrading strains also examined, some which could utilize phenolic substrates produced ' T O 2 from the [lignin-~4C]lignocellulose, and two of these were selected for further study. These strains, Thermomunospara mesophila and a Strvptoniycvs sp., attacked [ 'JC]lignin yielding ' T O 2 and water-soluble lJC-labelled compounds during primary growth. This activity was not accounted for by the utilization of phenolic acids linked to the carbohydrate fraction of wheat lignocellulose and was unaffected by cultural parameters known to influence lignin degradation by white-rot fungi,

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