PHYSIOLOGY OF SOME ACTINOMYCETE GENERA

Actinomycetes are widespread in the environment and are mainly organot rophic. Studies of their ecology have been primarily focussed on their detection and isolation, with comparatively little attention to the c ontrol mechanisms that determine their occurrence and behaviour in the ir natural environments. This session provided some diverse examples o f approaches to this problem. Several actinomycete genera produce moti le spores. The significance of flagella proteins and factors influenci ng spore motility and germination are considered. The genus Frankia fo rms nitrogen-fixing associations with non-leguminous plants. Molecular techniques have been used to clarify the endophyte-host relationships . Micromonospora species are common in the environment. The growth and physiology of a gentamicin-producing strain are described. Thermophil ic actinomycetes in the genus Thermoactinomyces are common in composts and other self-heating environments. Novel isolates from acid soil, w hich grow and produce enzymes active at high temperatures and in acidi c conditions, are discussed.