Juan Pablo Gomez-Escribano & Javier Santos Aberturas, John Innes Centre
Most of the compounds we use as antibiotics, or that we transform into useful antibiotics, are obtained from soil-dwelling microbes called actinomycetes. These bacteria grow as filaments on a solid substrate. When the environmental conditions are adequate, part of the filaments grow into the air and develop into spores, tiny but strong reproductive structures that can persist even under very tough conditions (very high or very low temperature, complete dryness).
In this macro-photograph you can see a very close view of a colony of the actinomycete Streptomyces coelicolor. It is not the original strain isolated from nature, it is an engineered derivative in which the tight control that normally regulates antibiotic production has been loosened, leading to an overproduction of the blue antibiotic actinorhodin. The loss of control has also resulted in an overgrowth of the colony, forming these amazing creases within which drops of water have condensed with accumulated blue antibiotic in very high concentration, hence the dark deep blue colour.