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Effect of Culture Conditions on Ergosterol as an Indicator of Biomass in the Aquatic Hyphomycetes

Charcosset, Jean-Yves and Chauvet, Eric Effect of Culture Conditions on Ergosterol as an Indicator of Biomass in the Aquatic Hyphomycetes. (2001) Applied and Environmental Microbiology, Vol. 6 (n° 5). pp. 2051-2055.

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Official URL: http://dx.doi.org/10.1128/AEM.67.5.2051-2055.2001

Abstract

Ergosterol is a membrane component specific to fungi that can be used to estimate fungal biomass using appropriate factors of conversion. Our objectives were to determine the limits of use of ergosterol content as a measure of biomass for aquatic hyphomycetes, and to evaluate a previously established ergosterol-to-biomass conversion factor. We varied inoculum quality, growth medium, and degree of shaking of four aquatic hyphomycete species. In cultures inoculated with homogenized mycelium, we found a significant effect of shaking condition and culture age on ergosterol content. In liquid cultures with defined medium, ergosterol content reached 10 to 11 mg/mg of mycelium (dry mass) and varied by factors of 2.2 during exponential growth and 1.3 during stationary phase. The increase in ergosterol content during exponential phase could be attributed, at least in part, to rapid depletion of glucose. Oxygen availability to internal hyphae within the mycelial mass is also responsible for the differences found between culture conditions. Ergosterol concentration ranged from 0.8 to 1.6 mg/mg in static cultures inoculated with agar plugs. Ergosterol content varied by a factor of 4 in two media of different richnesses. For different combinations of these parameters, strong (r2 5 0.83 to 0.98) and highly significant (P ! 0.001) linear relationships between ergosterol and mycelial dry mass (up to 110 mg) were observed. Overall, the ergosterol content varied by a factor of 14 (0.8 to 11 mg/g). These results suggest that care must be taken when the ergosterol content is used to compare data generated in different field environments.

Item Type:Article
Additional Information:Thanks to American Society for Microbiology.The definitive version is available at http://aem.asm.org/cgi/content/short/67/5/2051. The original PDF of the article can be found at Applied and Environmental Microbiology website:http://aem.asm.org/
Audience (journal):International peer-reviewed journal
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Institution: Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
French research institutions > Centre National de la Recherche Scientifique - CNRS
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Deposited By: Florence Amor
Deposited On:04 Jun 2010 15:11

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