In Aspergillus nidulans there is an NADP(+)-dependent glycerol dehydrogenase that is specifically induced on transfer to D-galacturonate medium. In contrast to the previously characterised constitutive NADP(+)-dependent glycerol dehydrogenase it has a much broader substrate specificity, having activity as an ethanol dehydrogenase, and is subject to carbon-catabolite repression. In addition to the two NADP(+)-dependent glycerol dehydrogenases, alcohol dehydrogenase I and II are also present on transfer to D-galacturonate medium, and have weak activity as glycerol dehydrogenases.

Acetate-non-utilizing mutants in

In Aspergillus nidulans three alcohol dehydrogenases (ADHs) have been described. ADHI is induced by ethanol and is the physiological enzyme of ethanol utilization, ADHll has not been attributed a function but is repressed by ethanol. The ALCR regulatory protein acts positively to induce ADHI, and negatively in its control of ADHII. ADHlll is specifically induced by anaerobic stress. We have characterized the substrate specificity of these three enzymes by looking at their staining profile on polyacrylamide gels with a range of alcohols. In addition to these enzymes we have observed six other NAD+-dependent ADHs, two of which, propan-2-01 dehydrogenase and pentan-2-01 dehydrogenase, share similar control with ADHII. The inducibility of these enzymes with some alcohols has also been investigated. The profile of ADHs with NADP' as an electron acceptor is also reported.

No abstract

It has been suggested that the regulation of plant growth by ethylene may involve modification of IAA transport. We have examined this theory and an account will be given of the effects of ethylene on lateral and longitudinal IAA transport in potato sprouts and stolons. The techniques employed included microautoradiography and a new micropipette injection system.