TY - JOUR
T1 - Production of an extracellular matrix as an isotropic growth phase of Penicillium rubens on gypsum
AU - Bekker, M.
AU - Huinink, H.P.
AU - Adan, O.C.G.
AU - Samson, R.A.
AU - Wyatt, T.
AU - Dijksterhuis, J.
N1 - Reporting year: 2012
PY - 2012
Y1 - 2012
N2 - Indoor mold represents an important environmental concern, but a fundamental knowledge of fungal growth stages is needed to limit indoor fungal proliferation on finishing materials used in buildings. The present study focused on the succession of germination stages of the common indoor fungus Penicillium rubens on a gypsum substrate. This substrate is used as a model system representing porous materials that are widely used in indoor environments. Imaging with cryo-scanning electron microscopy showed that the formation of an extracellular matrix (ECM) is a phase of the isotropic growth of P. rubens that is uniquely related to germinating conidia. Furthermore, the ECM is observed only when a dry-state inoculation of the surface is applied, i.e., applying conidia directly from a 7-day-old colony, mimicking airborne contamination of the surface. When inoculation is done by spraying an aqueous conidial suspension, no ECM is observed. Moreover, it is concluded that the formation of an ECM requires active processes in the fungal cell. The porosity of the substrate proved that the ECM substance has high-viscosity characteristics. The present results stress that studies of indoor fungal growth should consider the method of inoculation, knowing that the common aqueous suspension may obscure specific stages in the initial phases of germination. © 2012, American Society for Microbiology.
AB - Indoor mold represents an important environmental concern, but a fundamental knowledge of fungal growth stages is needed to limit indoor fungal proliferation on finishing materials used in buildings. The present study focused on the succession of germination stages of the common indoor fungus Penicillium rubens on a gypsum substrate. This substrate is used as a model system representing porous materials that are widely used in indoor environments. Imaging with cryo-scanning electron microscopy showed that the formation of an extracellular matrix (ECM) is a phase of the isotropic growth of P. rubens that is uniquely related to germinating conidia. Furthermore, the ECM is observed only when a dry-state inoculation of the surface is applied, i.e., applying conidia directly from a 7-day-old colony, mimicking airborne contamination of the surface. When inoculation is done by spraying an aqueous conidial suspension, no ECM is observed. Moreover, it is concluded that the formation of an ECM requires active processes in the fungal cell. The porosity of the substrate proved that the ECM substance has high-viscosity characteristics. The present results stress that studies of indoor fungal growth should consider the method of inoculation, knowing that the common aqueous suspension may obscure specific stages in the initial phases of germination. © 2012, American Society for Microbiology.
U2 - 10.1128/AEM.01506-12
DO - 10.1128/AEM.01506-12
M3 - Article
SN - 0099-2240
VL - 78
SP - 6930
EP - 6937
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
IS - 19
ER -