A Kinetic Study of the Colony Growth of Streptomyces coelicolor A3(2) and J802 on Solid Medium

Abstract

Colony growth kinetics of Streptomyces coelicolor A3(2), the wild-type strain, and 5802, a mutant incapable of utilizing agar as the sole carbon and energy source, have been studied on solid medium. General features comparable to colony growth of filamentous fungi were observed in both streptomycete strains. Hyphal frequency at the margins of colonies was assessed as the number of hyphae crossing an arc of defined length and increased in an exponential manner with distance from the margin, reaching a maximum at approximately 200 pm. Aerial hyphal initials were formed approximately 350 pm from the margin. Colony radial extension was linear, but in the wild-type strain grown at low medium depths, growth was sometimes multiphasic, with successive phases of linear growth each exhibiting a slower radial growth rate than that of the preceding phase. Hyphal frequency at the colony margin decreased as colony diameter increased, indicating significant changes in environmental conditions in the peripheral growth zone during colony growth. In the primary phase of linear growth, the colony radial growth rate of both strains was independent of medium depth and in the absence of a cellophane membrane was independent of glucose concentration. Colony radial growth rate of strain 5802 growing on a cellophane underlay increased with glucose concentration. Hyphal frequency of strain A3(2) increased gradually with medium depth but was independent of glucose concentration. In strain 5802, hyphal frequency exhibited a strong dependence on both medium depth and glucose concentration. A threshold glucose concentration for growth was not found and inhibition of strain A3(2) occurred above 1 g 1 -l . The results agree with many aspects of accepted theories for colony growth of both unicells and filamentous fungi, but suggest production of staling products and/or secondary metabolites to be of equal significance to nutrient limitation in controlling colony development.

Pleiotropic effects of cAMP on germination, antibiotic biosynthesis and morphological development in Streptomyces coelicolor

“…In the initial stages of germination, undefined signals trigger influx of water into spores, resulting in an increase in size and decreased phase brightness followed by germ‐tube emergence (Ensign, 1978; Hardisson et al ., 1978). Unlike unicellular bacteria, in which chromosome replication is followed by cell division, Streptomyces genomes remain associated in branching filaments, thereby generating a dense interconnected mycelial colony (Schuhmann and Bergter, 1976; Kretschmer, 1982; Allen and Prosser, 1985). Subsequently, discontinuous growth kinetics have been observed in numerous species (Holt et al ., 1992; Neumann et al ., 1996; Puglia et al ., 1995).…”

Mathematical Analysis of Growth and Interaction Dynamics of Streptomycetes and a Bacteriophage in Soil

“…In brief, spores germinate via a primary germ tube that undergoes branching after a period of linear extension and nucleoid replication. In Streptomyces coelicolor, mature colonies grow exponentially (as measured by DNA content) through linear (apical) extension of individual hyphae with an exponential increase in the number of branches (2). Exponential growth continues until limited through depletion of an essential nutrient, occupancy of all spatial niches, or the accumulation of staling compounds (3).…”

Growth of Micromycetes from Different Ecological Niches on Agar Nutrient Media

“…Міцелій покриває твер де середовище та засвоює з нього поживні речовини значно ефективніше, ніж, наприклад, колонії бактерій чи дріжджів. Кінетика росту міцеліальних грибів та актиноміцетів, а також утворення їх колоній є загальними [10,12,13,15,20].…”