ENVIRONMENTAL SIGNALS TRIGGERING METHYLENOMYCIN PRODUCTION BY STREPTOMYCES-COELICOLOR A3(2)

Methylenomycin production by Streptomyces coelicolor A3(2) may be trig gered by either of two environmental signals: alanine growth-rate-limi ting conditions and/or an acidic pH shock. The production of this SCP1 -encoded antibiotic was studied by using batch end chemostat cultures. Batch cultures indicated a role for both nutritional status and cultu re pH in its regulation. Steady-state methylenomycin production and tr anscription of an mmy gene under alanine but not glucose growth-rate-l imiting conditions was demonstrated in chemostat culture. Transient mm y expression and methylenomycin production occurred following an acidi c pH shock. This stimulation of methylenomycin production occurred ind ependently of the nutritional status of the growth environment. Antibi otic production was partially suppressed under alanine compared with g lucose growth-rate-limiting conditions following the acidic pH shock. A low specific growth rate was a prerequisite for both steady-state an d transient production of methylenomycin.