In situ monitoring of chitin degradation by Streptomyces lividans pCHIO12 within Enchytraeus crypticus (Oligochaeta) feeding on Aspergillus proliferans

Enchytraeus crypticus (Oligochaeta) subsists on the fungus Aspergillus prol iferans. The proliferation can be considerably enhanced by co-feeding the G ram-positive bacterium Streptomyces lividans pCHIO12 overproducing an exoch itinase. In situ hybridizations with 23S rRNA-targeting, fluorescein-labell ed oligonucleotides revealed that S. lividans pCHIO12 survives well within the gut of E. crypticus. Immunological analyses using a rhodamine-labelled alpha-chitin-binding protein (CHB1) allowed the conclusion that the bacteri al enzyme degrades chitin within hyphae of A. proliferans. Our data show th at the established in situ monitoring methods are valuable tools to analyze interactions between Enchytraeidae and microorganisms. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.