Fine Structure, Physiology and Biochemistry of Arthrospore Germination in Streptomyces antibioticus

Abstract

203During germination, Streptomyces antibioticus arthrospores passed through three stages : darkening, swelling and germ tube emergence. The first stage, darkening, whose main features were a decrease in absorbance and a loss of refractility, only required exogenous divalent cations (Ca2+, Mg2+ or Fe2+) and energy that can be obtained from the spore reserves. This stage was blocked by agents that inhibit ATP formation but not by antibiotics that inhibit macromolecular synthesis. The second stage, swelling, needed an excgenous carbon source and was not blocked by mitomycin C. In this stage, the spores exhibited the highest cytochrome oxidase and catalase activities and respiratory quotient. The last stage, germ tube emergence, required additional carbon and nitrogen sources. Ammonium compounds were superior to nitrate. Dry weight remained constant during the stages of darkening and swelling, with a rapid increase from the moment of germ tube emergence. Optimum pH and temperature for germination were 8.0 and 45 "C, respectively. Heat treatment (55 "C for 10 min) had no effect on germination.The fine structure of the spore underwent important changes during germination. The wall of the swollen spore became stratified and the inner layer was continuous with the germ tube wall.Macromolecular synthesis occurred in the sequence RNA, protein and then DNA. Rifampicin, streptomycin and mitomycin C prevented synthesis when added at the start of incubation. The same effect was obtained if the addition was made during germination, except with mitomycin C which inhibited DNA, but not RNA and protein synthesis.

Glycogen and Trehalose Accumulation during Colony Development in Streptomyces antibioticus

“…Streptomyces antibioticus ATCC 1 1891 was grown as lawns on sterile cellophane films placed on solid glucose/asparagine/yeast extract medium (GAE medium;. The plates (containing 30 ml culture medium) were inoculated by spreading 0.2 ml of a spore suspension, obtained as described previously (Hardisson et al, 1978), on the surface of the cellophane and were incubated at 28°C. The developmental stage of colonial growth was followed by observing the changes in coloration of the surface of the cultures, and by light microscopic observation of semi-thin sections of the colonies (Mendez et al, 1985~).…”

Enzymatic Control of the Related Pathways of Fatty Acid and Undecylprodiginine Biosynthesis in <i>Streptomyces coelicolor</i>

“…Subsequently in response to nutrient depletion and other signals, some hyphae start growing away from the surface to form the aerial mycelium. Aerial growth coincides with the initiation of both production of secondary metabolites and morphological differentiation [5]. When growth of the aerial mycelium stops, they develop septa which include one nucleoid per cell compartment.…”

Purification and characterization of an extracellular enzyme from Streptomyces antibioticus that converts inactive glycosylated oleandomycin into the active antibiotic

“…Spore suspensions were obtained after sporulation on glucose/asparagine/yeast extract solid medium plates (Hardisson et al, 1978) kept at 30°C for 7 days. Growth in liquid cultures was achieved using 2-1 conical flasks containing 500 ml buffered minimal medium consisting of (g/l): glucose, 10; asparagine, 2; (NH,), SO,,2;MgS04,0.5;FeSO,,0.01;K,PO,H,4.28;KP04H2,0.81.…”