An exploratory comparative study of volatile compounds in exhaled breath andemitted by skin using selected ion flow tube mass spectrometry

摘要

This study examined the utilization patterns of key Carbon sources (CS, 24:including key sugars, aminoacids and fatty acids) in maize by strains ofAspergillus flavus and Fusarium verticillioides under different water activity(aw, 0.87-0.98 aw) and temperature (20-35°C) values and compared the nicheoverlap indices (NOI) that estimate the in vitro carbon source utilizationprofiles (Wilson and Lindow, 1994). The ability to grow in these key CS inminimal media was studied for 120 hrs in 12 hr steps. The NOI was calculated forinter-species (F. verticillioides – A. flavus) and for intra-species (A. flavus- A. flavus) using CS utilisation patterns over the range of interactingenvironmental conditions. 30°C, over the whole aw range examined, was found tobe optimal for utilization of the maximum number of CS by A. flavus. Incontrast, for F. verticillioides this was more so at 20°C; 25°C allowed asuboptimal usage of CS for both species. NOIs confirmed the nutritionaldominance of A. flavus at 30°C, especially at lower aw levels and that of F.verticillioides at 20°C, mainly at 0.95 aw. In other conditions of aw, based onCS utilization patterns, the data indicated that A. flavus and F.verticillioides occupied different ecological niches. The variability innutritional sources utilization between A. flavus strains was not related totheir ability to produce aflatoxins (AFs). This type of data helps to explainthe nutritional dominance of fungal species and strains under differentenvironmental conditions. This could be useful in trying to find appropriatenatural biocontrol microorganisms to compete with these mycotoxigenic