title: Combining microdilution with MicroResp™: microbial substrate utilization, antimicrobial susceptibility and respiration.
abstract: Pharmacological studies focus on susceptibility of pathogenic microbes against specific drugs or combinations of them, ecological studies on substrate utilization efficiency of variable microbial communities. The MicroResp™ system was especially developed to study soil microbial communities. It was slightly modified to facilitate exploring of microbial growth efficiency in a concentration-dependent fashion (microdilutions of carbohydrate mixtures or specific toxic chemicals). After turbidimetric growth assessment, colorimetric indicator plates (cresol red agar) were mounted to the assay plates. The substrate utilisation design is illustrated by glucose and a plant carbohydrate mixture, the antimicrobial susceptibility design by the naphthoquinone juglone. Dose-response effects are explored by curve fitting of nonlinear models that especially have been developed to detect hormetic effects that are characterized by stimulation at lower followed by inhibition at higher dosages (U- and inverse U-shaped effects). Multivariate analyses are presented utilizing metavariables that were obtained in the curve fitting process of the measured parameters growth and respiration and the factor growth efficiency.
authors.affiliation: Department of Chemical Ecology and Ecosystem Research, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
authors.forename: Sigrid
authors.initials: S
authors.lastname: Drage
authors.forename: Doris
authors.initials: D
authors.lastname: Engelmeier
authors.forename: Gert
authors.initials: G
authors.lastname: Bachmann
authors.forename: Angela
authors.initials: A
authors.lastname: Sessitsch
authors.forename: Birgit
authors.initials: B
authors.lastname: Mitter
authors.forename: Franz
authors.initials: F
authors.lastname: Hadacek
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000145:classification* / Q000187:drug effects* / Q000378:metabolism; D015373:Bacterial Typing Techniques / Q000379:methods*; D050260:Carbohydrate Metabolism; D003470:Culture Media / Q000737:chemistry; D008826:Microbial Sensitivity Tests / Q000379:methods; D010084:Oxidation-Reduction
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media