Metabolism of endogenous trehalose by Streptomyces griseus spores and by spores or cells of other actinomycetes

Abstract

The disaccharide trehalose is accumulated as a storage product by spores of Streptomyces griseus. Nongerminating spores used their trehalose reserves slowly when incubated in buffer for several months. In contrast, spores rapidly depleted their trehalose pools during the first hours of germination. Extracts of dormant spores contained a high specific activity of the enzyme trehalase. The level of trehalase remained relatively constant during germination or incubation in buffer. Nongerminating spores of Streptomyces viridochromogenes, Streptomyces antibioticus, and Micromonospora echinospora and nongrowing spherical cells of Arthrobacter crystalopoietes and Nocardia coralina also maintained large amounts of trehalose and active trehalase. These trehalose reserves were depleted during spore germination or outgrowth of spherical Arthrobacter and Nocardia cells into rods.Large amounts of the disaccharide trehalose are present in the dormant spores or cysts of a variety of organisms including actinomycetes, fungi, nematodes, and brine shrimp (1,3,5,6,18). Trehalose is degraded very slowly by these organisms during periods of dormancy but is rapidly metabolized following the onset of vegetative growth (2,11,20,22).We previously reported (15, 18) the accumulation of large amounts of trehalose by spores of Streptomyces griseus and the effects of trehalose content on spore properties. In this report we describe the results of an investigation of the metabolism of the endogenous reserves of trehalose by dormant and germinating spores of S. griseus. Results of studies of the metabolism of trehalose by some other actinomycetes are also described. MATERIALS AND METHODSGrowth conditions. S. griseus NRRL B-2682 spores were harvested from DMC agar as described previously (18 Germination conditions for S. griseus spores. The complex germination medium contained 0.5% yeast extract and 0.5% casein hydrolysate in 10 mM 3-morpholinepropanesulfonic acid (MOPS) buffer (pH 7.0). The defined germination medium consisted of 10 mM potassium phosphate buffer (pH 7.0)-5 mM (NH4)2SO4-0.5 mM MgSO4-7.6 mM Lisoleucine-7.6 mM L-leucine-8.5 mM L-valine-4.9 mM Ltryptophan-0.75 mM adenosine-14 mM glucose. In some experiments glucose was replaced by 27 mM glycerol. Spores were heat activated (15 min at 45°C) in 10 mM glycine buffer (pH 9.5), rapidly cooled to 0°C, and washed 3 times with 10 mM potassium phosphate buffer (pH 7.0) by centrifugation. Activated spores were inoculated into the germination media at final concentrations of approximately 2 x 108 spores per ml. The spores were incubated in 100 ml of medium in 1-liter flasks at 33°C with shaking at 185 rpm.Germination was monitored microscopically and was quantitated by taking advantage of the relative resistance of dormant spores to dilute acid. The number of acid-resistant CFUs was used to measure the number of dormant spores during sporulation or germination. Samples (0.2 ml) were added to 0.8 ml of 0.125 N HCI, dispersed by gentle sonication in a sonic water bath (Heat Systems Ultrasonics...

Organic solutes in Rubrobacter xylanophilus: the first example of di-myo-inositol-phosphate in a thermophile

“…Generally, glutamate, proline and ectoine are the most abundant compatible solutes of those Bacteria, while a few high G + C Gram-Positive Bacteria (Phylum Actinobacteria) studied, namely corynebacteria and streptomycetes accumulate trehalose, proline, glutamine and alanine under osmotic stress (Shimakata and Minatogawa 2000;Wolf et al 2003). These organisms as well as mycobacteria accumulate a low steady-state trehalose pool, and in some Streptomyces sp., trehalose is also involved in spore germination being implicated in their heat and desiccation resistance (McBride and Ensign 1987;Woodruff et al 2004 Glycine betaine (GB), a common compatible solute of mesophilic prokaryotes, was a minor solute in R. xylanophilus grown in Thermus medium, indicating that it was taken up, along with glutamate, from the yeast extract and tryptone. This solute cannot, however, have a role in osmotic adjustment in this organism because of the minor amounts accumulated.…”

Trehalose accumulation in vegetative cells and spores of Myxococcus xanthus

“…Growth was observed in CTH containing up to 0.3 M NaCl but not in medium containing 0.4 M NaCl. Cells harvested from media containing elevated levels of various (12). No trehalase activity was detected in these extracts.…”

“…The spores of all members of these groups that have been examined accumulate trehalose (1,11,17). In each of these organisms trehalose is metabolized slowly by dormant cells but is rapidly metabolized during germination (12,17). These similarities suggest that this pattern of trehalose accumulation and metabolism confers some selective advantage on these organisms in their natural environments.…”

“…Trehalose is generally degraded very slowly within dormant spores or cysts of the organisms that accumulate this sugar but is rapidly metabolized following the onset of vegetative growth (12,17). Trehalose metabolism is controlled by a reversible activation of the trehalase enzyme of some fungi.…”

Regulation of trehalose metabolism by Streptomyces griseus spores

“…In these organisms trehalose is degraded very slowly during periods of dormancy but is rapidly metabolized following the onset of vegetative growth (1,9,14,20,22).…”