Trehalose degradation and glucose efflux precede cell ejection during germination of heat-resistant ascospores of Talaromyces macrosporus

TY - JOUR

T1 - Trehalose degradation and glucose efflux precede cell ejection during germination of heat-resistant ascospores of Talaromyces macrosporus

AU - Dijksterhuis, Jan

AU - van Driel, Kenneth G A

AU - Sanders, Mark G

AU - Molenaar, Douwe

AU - Houbraken, Jos A M P

AU - Samson, Rob A

AU - Kets, Edwin P W

PY - 2002/7

Y1 - 2002/7

N2 - Talaromyces macrosporus forms ascospores that survive pasteurization treatments. Ascospores were dense (1.3 g ml(-1)), relatively dry [0.6 g H(2)O (g dry weight)(-1)] and packed with trehalose (9-17% fresh weight). Trehalose was degraded to glucose monomers between 30 and 100 min after heat activation of the spores. The maximal activity of trehalase was calculated as 400-520 nmol glucose formed min(-1) (mg protein)(-1) as judged by measurements of the trehalose content of spores during germination. During early germination, glucose was released from the cell (10% of the cell weight or more). The intracellular concentration of glucose only peaked briefly. After 160-200 min, the protoplast encompassed by the inner cell wall was ejected through the outer cell wall in a very quick process. Subsequently, respiration of spores increased strongly. The data suggested that trehalose is primarily present for the protection of cell components as glucose is released from the cell. Then, an impenetrable outer cell wall is shed before metabolic activity increases.

AB - Talaromyces macrosporus forms ascospores that survive pasteurization treatments. Ascospores were dense (1.3 g ml(-1)), relatively dry [0.6 g H(2)O (g dry weight)(-1)] and packed with trehalose (9-17% fresh weight). Trehalose was degraded to glucose monomers between 30 and 100 min after heat activation of the spores. The maximal activity of trehalase was calculated as 400-520 nmol glucose formed min(-1) (mg protein)(-1) as judged by measurements of the trehalose content of spores during germination. During early germination, glucose was released from the cell (10% of the cell weight or more). The intracellular concentration of glucose only peaked briefly. After 160-200 min, the protoplast encompassed by the inner cell wall was ejected through the outer cell wall in a very quick process. Subsequently, respiration of spores increased strongly. The data suggested that trehalose is primarily present for the protection of cell components as glucose is released from the cell. Then, an impenetrable outer cell wall is shed before metabolic activity increases.

KW - Talaromyces

KW - ascospores

KW - dormancy

KW - germination

KW - trehalose

KW - trehalase

KW - heat-resistant fungi

U2 - 10.1007/s00203-002-0410-x

DO - 10.1007/s00203-002-0410-x

M3 - Article

C2 - 12070763

SN - 0302-8933

VL - 178

SP - 1

EP - 7

JO - Archives of Microbiology

JF - Archives of Microbiology

IS - 1

ER -