Transport of Hexoses in <i>Streptomyces violaceoruber</i>

Transport of glucose, mannose and fructose has been studied in spores and mycelia of Streptomyces violaceroruber grown under a variety of nutritional conditions. Each of the three sugars is transported into mycelial cells by a specific, constitutive transport system. The apparent Michaelis constants of these systems for glucose, mannose and fructose are 1, 1.5 and 3 mM, respectively. At least in the case of mannose and fructose, transport seems to be of the non‐active type. In contrast with vegetative cells, spores of Streptomyces appreciably transport only glucose, with a Km of 1 mM, but not mannose and fructose. This observation can be related to the lag for growth of Streptomyces spores on mannose or fructose with respect to growth on glucose.