Monitoring MVOC Profiles over Time from Isolates of Aspergillus flavus Using SPME GC-MS

Sun, Dongdi; Wood-Jones, Alicia; Wang, Wenshuang; Vanlangenberg, Chris; Jones, David S.; Gower, Julie L.; Simmons, Patrice; Baird, Richard E.; Mlsna, Todd

doi:10.4236/jacen.2014.32007

Cited by 13 publications

(15 citation statements)

References 28 publications

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“…To the best of our knowledge, none of the reported molecules have previously been measured in the headspace of A. fumigatus cultures, likely because the hypoxia-associated volatile metabolome of this organism has never been measured. Five of the six molecules (excluding benzonitrile) have, however, been measured in the headspace of either Aspergillus flavus or Aspergillus niger cultures [35, 36]. …”

Section: Resultsmentioning

confidence: 99%

Sniffing out the hypoxia volatile metabolic signature ofAspergillus fumigatus

et al. 2017

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Invasive Aspergillosis (IA) is a life-threatening infectious disease caused by fungi from the genus Aspergillus, with an associated mortality as high as 90% in certain populations. IA-associated pulmonary lesions are characteristically depleted in oxygen relative to normal lung tissue, and it has been shown that the most common causal agent of IA, Aspergillus fumigatus, must respond to low-oxygen environments for pathogenesis and disease progression. Previous studies have demonstrated marked alterations to the Aspergillus fumigatus transcriptome in response to low oxygen environments that induce a “hypoxia response.” Consequently, we hypothesized that these transcriptomic changes would alter the volatile metabolome and generate a volatile hypoxia signature. In the present study, we analyzed the volatile molecules produced by A. fumigatus in both oxygen replete (normoxia) and depleted (hypoxia) environments via headspace solid-phase microextraction coupled to two-dimensional gas chromatography-time-of-flight mass spectrometry (HS-SPME-GC×GC-TOFMS). Using the machine learning algorithm Random Forest, we identified 19 volatile molecules that were discriminatory between the four growth conditions assessed in this study (i.e., early hypoxia (1 h), late hypoxia (8 h), early normoxia (1 h), and late normoxia (8 h)), as well as a set of 19 that were discriminatory between late hypoxia cultures and all other growth conditions in aggregate. Nine molecules were common to both comparisons, while the remaining 20 were specific to only one of two. We assigned putative identifications to 13 molecules, of which six were most highly abundant in late hypoxia cultures. Previously acquired transcriptomic data identified putative biochemical pathways induced in hypoxia conditions that plausibly account for the production of a subset of these molecules, including 2,3-butanedione and 3-hydroxy-2-butanone. These two molecules may represent a novel hypoxia fitness pathway in A. fumigatus, and could be useful in the detection of hypoxia-associated A. fumigatus lesions that develop in established IA infections.

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Section: Resultsmentioning

confidence: 99%

Sniffing out the hypoxia volatile metabolic signature ofAspergillus fumigatus

et al. 2017

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“…Using peak area %, the RSD%'s of CAR/PDMS, DVB/CAR/PDMS and DVB/PDMS are 56.7%, 52.1% and 39.5%, respectively. Previous studies show that RSD%'s determined using analytical standards calculated by peak area were 18.4%, 14.9% and 13.1%, for CAR/PDMS, DVB/CAR/PDMS and DVB/PDMS, respectively [32]. Several volatile metabolites show large fluctuations in concentration under identical experimental condition; this is due in part to uninduced biological variation [48].…”

Section: Evaluation Of Spme Fiber On Metabolic Profilingmentioning

confidence: 99%

“…For SPME fiber evaluation, the extraction efficiencies of three commercially available SPME fibers coated with carboxen/polydimethylsiloxane (CAR/PDMS), divinylbenzene/polydimethylsiloxane (DVB/PDMS) and carboxen/divinylbenzene /PDMS were compared. A single A. flavus isolate was selected for this study in an attempt to reduce variations due to phenotype differences associated with different isolates [32]. For the growth parameters' effect study, the A. flavus isolate was grown under varied conditions using different temperatures and numbers of spores inoculated and on different substrates to evaluate the influence of these factors on MVOCs' production.…”

Section: Introductionmentioning

confidence: 99%

“…Sampling methods, such as thermal desorption tube (Tenax TA) [4,26,27], purge and trapping of headspace gases [28,29], headspace sorptive extraction [12,30] and solid phase microextraction (SPME) [31][32][33][34], have been used for the collection of MVOCs. SPME is a popular technique because it has the advantages of low cost per analysis and portability.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Growth Parameters on the Analysis of Aspergillus flavus Volatile Metabolites

et al. 2016

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Aspergillus flavus produces dangerous secondary metabolites known as aflatoxins, which are toxic and carcinogenic, and their contamination of agricultural products results in health issues and economic hardships in the U.S. and around the world. Early identification of aflatoxigenic isolates of A. flavus is the key in the management of these fungi. An emerging detection method for specific fungi identification involves the analysis of microbial volatile organic compounds (MVOCs) released by the fungi. Complicating this approach is the understanding that many factors influence metabolic production, including growth parameters, such as growth media, temperature, spore counts and oxidation stress. In addition, analytical and data analysis methods can also influence the results. Several growth and analysis methods were evaluated and optimized in order to better understand the effect of the methods on fungi MVOC signatures. The results indicate that carboxen/polydimethylsiloxane (CAR/PDMS) has the best extraction efficiency for the MVOCs emitted by A. flavus. Both chemical defined agar (CDA) and chemical defined liquid (CDL) are suitable growth media for MVOC emission studies. The highest MVOC production was found at 30˝C. Log transformation was considered one of the best data pretreatment methods when analyzing MVOC data and resulted in the best principal component analysis (PCA) clustering in the experiments with different growth media. This study aims to elucidate fungal volatile organic compounds (VOCs) differences due to variations in growth parameters as a first step in the development of an analytical method for the monitoring of aflatoxigenic A. flavus contamination in crop storage facilities.

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“…In our study, we have identified 57 compounds already known to be emitted by fungi (Table 1). In particular, we have identified 13 compounds known to be associated with the fungal presence (a in Table 1) and/or the genus Aspergillus (b in Table 1), and more precisely, 44 compounds known in the literature to be involved with the presence of A. flavus strains (c in Table 1) [10,23,[28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. In addition, 20 compounds (not counting the 6 unidentified compounds) were identified for the first time to be emitted by A. flavus.…”

Section: Mvocsmentioning

confidence: 99%

Volatile Organic Compounds Emitted by Aspergillus flavus Strains Producing or Not Aflatoxin B1

Josselin

Clerck

Boevre

et al. 2021

Toxins

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Aspergillus flavus is a phytopathogenic fungus able to produce aflatoxin B1 (AFB1), a carcinogenic mycotoxin that can contaminate several crops and food commodities. In A. flavus, two different kinds of strains can co-exist: toxigenic and non-toxigenic strains. Microbial-derived volatile organic compounds (mVOCs) emitted by toxigenic and non-toxigenic strains of A. flavus were analyzed by solid phase microextraction (SPME) coupled with gas chromatography–mass spectrometry (GC-MS) in a time-lapse experiment after inoculation. Among the 84 mVOCs emitted, 44 were previously listed in the scientific literature as specific to A. flavus, namely alcohols (2-methylbutan-1-ol, 3-methylbutan-1-ol, 2-methylpropan-1-ol), aldehydes (2-methylbutanal, 3-methylbutanal), hydrocarbons (toluene, styrene), furans (2,5-dimethylfuran), esters (ethyl 2-methylpropanoate, ethyl 2-methylbutyrate), and terpenes (epizonaren, trans-caryophyllene, valencene, α-copaene, β-himachalene, γ-cadinene, γ-muurolene, δ-cadinene). For the first time, other identified volatile compounds such as α-cadinol, cis-muurola-3,5-diene, α-isocomene, and β-selinene were identified as new mVOCs specific to the toxigenic A. flavus strain. Partial Least Square Analysis (PLSDA) showed a distinct pattern between mVOCs emitted by toxigenic and non-toxigenic A. flavus strains, mostly linked to the diversity of terpenes emitted by the toxigenic strains. In addition, the comparison between mVOCs of the toxigenic strain and its non-AFB1-producing mutant, coupled with a semi-quantification of the mVOCs, revealed a relationship between emitted terpenes (β-chamigrene, α-corocalene) and AFB1 production. This study provides evidence for the first time of mVOCs being linked to the toxigenic character of A. flavus strains, as well as terpenes being able to be correlated to the production of AFB1 due to the study of the mutant. This study could lead to the development of new techniques for the early detection and identification of toxigenic fungi.

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Monitoring MVOC Profiles over Time from Isolates of Aspergillus flavus Using SPME GC-MS

Cited by 13 publications

References 28 publications

Sniffing out the hypoxia volatile metabolic signature ofAspergillus fumigatus

Sniffing out the hypoxia volatile metabolic signature ofAspergillus fumigatus

Effects of Growth Parameters on the Analysis of Aspergillus flavus Volatile Metabolites

Volatile Organic Compounds Emitted by Aspergillus flavus Strains Producing or Not Aflatoxin B1

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