resistance properties of their spores (90 for 30 min) and resistance to novobiocin (25ml).(cel.lulolytic activity is absenr in thermoactinomycetes but common in thermomonospora) thermoactinomycetes spore are extrely long-lived and can be isolared from soi and sediment cores. they have been implicated in various forms of hypersensivity pneuonisis (extrinsic allergic alveolitis).