References of "Stefanuto, Pierre-Hugues"
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See detailAdvanced method optimization for volatile aroma profiling of beer using two-dimensional gas chromatography time-of-flight mass spectrometry
Stefanuto, Pierre-Hugues ULg; Perrault, Katelynn ULg; Dubois, Lena ULg et al

in Journal of Chromatography. A (2017)

The complex mixture of volatile organic compounds (VOCs) present in the headspace of Trappist and craft beers was studied to illustrate the efficiency of thermal desorption (TD) comprehensive two ... [more ▼]

The complex mixture of volatile organic compounds (VOCs) present in the headspace of Trappist and craft beers was studied to illustrate the efficiency of thermal desorption (TD) comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS) for highlighting subtle differences between highly complex mixtures of VOCs. Headspace solid-phase microextraction (HS-SPME), multiple (and classical) stir bar sorptive extraction (mSBSE), static headspace (SHS), and dynamic headspace (DHS) were compared for the extraction of a set of 21 representative flavor compounds of beer aroma. A Box-Behnken surface response methodology experimental design optimization (DOE) was used for convex hull calculation (Delaunay’s triangulation algorithms) of peak dispersion in the chromatographic space. The predicted value of 0.5 for the ratio between the convex hull and the available space was 10% higher than the experimental value, demonstrating the usefulness of the approach to improve optimization of the GC × GC separation. Chemical variations amongst aligned chromatograms were studied by means of Fisher Ratio (FR) determination and F‐distribution threshold filtration at different significance levels (α = 0.05 and 0.01) and based on z‐score normalized area for data reduction. Statistically significant compounds were highlighted following principal component analysis (PCA) and hierarchical cluster analysis (HCA). The dendrogram structure not only provided clear visual information about similarities between products but also permitted direct identification of the chemicals and their relative weight in clustering. The effective coupling of DHS-TD-GC × GC-TOFMS with PCA and HCA was able to highlight the differences and common typical VOC patterns among 24 samples of different Trappist and selected Canadian craft beers. [less ▲]

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See detailSniffing Out the Hypoxia Volatile Metabolic Signature of Aspergillus fumigatus
Stefanuto, Pierre-Hugues ULg; Rees, Christiaan A.; Beattie, Sarah R. et al

Poster (2017, May)

Background: Aspergillus fumigatus is responsible for the life-threatening infection invasive aspergillosis (IA) that is associated with high mortality in immunocompromised individuals. Current diagnostics ... [more ▼]

Background: Aspergillus fumigatus is responsible for the life-threatening infection invasive aspergillosis (IA) that is associated with high mortality in immunocompromised individuals. Current diagnostics for IA are either highly invasive or suffer from inadequate sensitivity and/or specificity. Improvement of IA diagnostic assays requires a better understanding of fungal metabolism inside the host. The infection microenvironment becomes progressively depleted of oxygen during IA. Thus, metabolites associated with hypoxia metabolism may yield to novel diagnostic biomarkers. Here, we report on the volatile metabolites emitted from A. fumigatus batch cultures under normoxia and hypoxia conditions. Methods: A. fumigatus strain CEA10 was incubated in glucose minimal medium at 37 °C under either normoxia (21% O2, 0.04% CO2) or hypoxia (0.2% O2, 5% CO2) growth conditions. Volatile molecules from the supernatants of early (1 h) and late (8 h) cultures were collected using headspace solid-phase microextraction (HS-SPME) and analyzed using two-dimensional gas chromatography-time-of-flight mass spectrometry (GCxGC-TOFMS). Results: We identified 10 volatile compounds that are significantly more abundant in late hypoxia cultures compared with all other experimental conditions. Among these compounds, we identified ethanol and acetaldehyde, which are known to result from hypoxia metabolism of glucose by A. fumigatus. In addition, we detected 2-propanol, which can be generated by the reduction of acetone via alcohol dehydrogenase, as well as 2,3-butanedione (diacetyl) and 3-hydroxy-2-butanone (acetoin), which results from the catabolism of acetolactate. Transcriptomic data collected from normoxia and hypoxia cultures validates our volatilomic findings through the identification of putative catabolic pathways that are upregulated during hypoxia growth. Diacetyl is known to be produced by bacteria as a pH-neutral fermentative byproduct to prevent lethal acidification, and we speculate that A. fumigatus may use the same pathway. Conclusion: The composition of A. fumigatus’ volatile metabolome changes according to the oxygen tension in the environment. We measured hypoxia-associated compounds, ethanol and acetaldehyde which have been previously identified as byproducts of hypoxia metabolism in this organism. 2-propanol, 2, 3-butanedione and 3-hydroxy-2-butanone represent novel metabolites that suggests the existence of other catabolic pathways activated in A. fumigatus under hypoxia growth conditions. [less ▲]

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See detailIdentifying infectious agents from lung transplant patients using GC×GC-TOFMS
Stefanuto, Pierre-Hugues ULg; Rees, Christiaan A.; Romamno, Rosalba et al

Poster (2017, May)

During the first year post-surgery, bacterial and fungal infections are the main causes of death in lung transplant recipients. Contributing substantially to the high mortality rate (35%) is the lengthy ... [more ▼]

During the first year post-surgery, bacterial and fungal infections are the main causes of death in lung transplant recipients. Contributing substantially to the high mortality rate (35%) is the lengthy time-to-diagnosis, which includes both pathogen identification and antibiotic resistance profiling. A novel diagnostic strategy based on the detection of volatile compounds in breath seems a promising option to improve these patients’ outcomes. In order to demonstrate the feasibility of this approach, we characterized the volatile fraction of different clinical matrices (i.e., bronchoalveolar lavage (BAL) and blind bronchial aspirate (BBA)). Due to the complexity of the mixture and high dynamic range of the concentrations, we applied headspace solid phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS) to obtain a comprehensive overview of the sample headspace composition. Following the analytical step, we applied various univariate and multivariate statistical methods (e.g. random forest, principal component analysis, and hierarchical cluster analysis) in order to extract required information from the data. Based on the composition of the volatile fraction, we were able to differentiate between BAL and BBA with a classification accuracy of 88.4 %. Furthermore, we could correctly distinguish between individuals with active respiratory infections and those without infection with a 72.2 % classification accuracy. In some cases, it was also possible to differentiate between pathogens at the species level. These results are preliminary evidence to suggest the possibility of detecting infections in these patient without the use of time-consuming culture techniques. [less ▲]

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See detailIdentifying novel biomarkers for the rapid diagnosis of invasive aspergillosis using GC×GC-TOFMS
Stefanuto, Pierre-Hugues ULg; Rees, Christiaan A.; Beattie, Sarah R. et al

Conference (2017, May)

Aspergillus fumigatus is a filamentous fungus responsible for the life-threatening infection, invasive aspergillosis (IA), in immunocompromised individuals. Currently, IA diagnostic methods take days to ... [more ▼]

Aspergillus fumigatus is a filamentous fungus responsible for the life-threatening infection, invasive aspergillosis (IA), in immunocompromised individuals. Currently, IA diagnostic methods take days to produce a result and methods to obtain samples are invasive. One approach to improve the time-to-diagnosis is based on utilizing our knowledge of fungal metabolism during pathogenesis. Recent studies have demonstrated the importance of oxygen availability during IA, which presents a potential diagnostic opportunity. In this study, we analyzed the early (1 hr) and late (8 hr) volatile profile of A. fumigatus strain CEA1o under oxygen replete (~20% O2) and deplete (0.2% O2) conditions. In order to comprehensively screen the headspace of these cultures, we applied headspace solid phase microextraction (HS-SPME) associated with comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (GC×GC-TOFMS). Comparing the headspace of the four culture conditions, we were able to identify specific volatile biomarkers of low oxygen fungal growth: ethanol, acetaldehyde, 2-propanol, 2,3-butanedione, and 3-hydroxy-2-butanone. Based on the putative identifications of these compounds, we identified potential metabolic pathways that are responsible for their production. The two first compounds are known to be produced during hypoxia metabolism of glucose, however, the three others suggest that previously uncharacterized metabolic pathways may be utilized by A. fumigatus in low oxygen conditions. Validation of these biomarker identities and translation into patients may generate metabolic insight into these organisms during IA pathogenesis. [less ▲]

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See detailThe Case of the Decaying Cadaver
Stefanuto, Pierre-Hugues ULg; Focant, Jean-François ULg

in The Analytical Scientist (2017), 51

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See detailThe Odor of Death: An Overview of Current Knowledge on Characterization and Applications
Verheggen, François ULg; Perrault, Katelynn ULg; Caparros Megido, Rudy ULg et al

in Bioscience (2017)

After death, the human body undergoes various processes that result in the emission of volatile organic compounds (VOCs). The interest in these VOCs has increased substantially in recent years because ... [more ▼]

After death, the human body undergoes various processes that result in the emission of volatile organic compounds (VOCs). The interest in these VOCs has increased substantially in recent years because they are key attractants for necrophagous insects and vertebrate scavengers. Identifying cadaveric VOCs has required the effective development of analytical tools for collecting, separating, identifying, and quantifying the suite of VOCs released throughout decomposition. Analytical developments for studying cadaveric VOCs in vertebrates, ecological interactions of cadaveric VOCs with the abiotic and biotic environment, and the necessity for convergence of these two areas for the progression of future knowledge are discussed herein. [less ▲]

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See detailProfiling Volatile Organic Compounds of Decomposition
Stefanuto, Pierre-Hugues ULg; Rosier, E; Tytgat, J et al

in Schotsmans, E; Marquez-Grant, N; Forbes, S (Eds.) Taphonomy of Human Remains (2017)

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See detailA new method for identifying experimental and Palaeolithic hafting adhesives using GC×GC-HRTOFMS
Cnuts, Dries ULg; Perrault, Katelynn ULg; Dubois, Lena ULg et al

Poster (2016, September)

Hafting adhesives can be seen as an indication of the cognitive and technical capabilities of the manufacturers and therefore play a key role in the debate on human evolution [1], [2]. These adhesives are ... [more ▼]

Hafting adhesives can be seen as an indication of the cognitive and technical capabilities of the manufacturers and therefore play a key role in the debate on human evolution [1], [2]. These adhesives are mainly from plant origin (resins, gums or tar) and are often mixed with beeswax and other additives in order to make them less brittle. Archaeological evidence indicates that these adhesives were already in use in the Paleolithic from at least 120.000 years ago [3]. Discoveries for this period are however very rare and only become abundant from the Neolithic onwards [4]. Their longer exposure to biochemical alteration processes limits the chance of survival in the archaeological record. If they are present on Paleolithic stone tools, they appear often in such small quantities that they are challenging to identify by traditional gas chromatography – mass spectrometry (GC-MS) or even to remove them effectively from the stone tool. The destructive nature of traditional GC-MS analysis can damage these rare samples for other analyses. Our study aims to overcome this problem by using headspace solid phase microextraction (HS-SPME) for sample extraction and analysis by comprehensive two-dimensional gas chromatography –high-resolution time-of-flight mass spectrometry (GC×GC-HRTOFMS), which has the benefit of analyzing the volatile organic compound (VOC)s from the substance and it does not destroy the complete matrix of the adhesive. We present the results of a pilot study intended to examine the potential of this technique for analyzing Palaeolithic adhesives. The study involved (1) an examination of experimental compound adhesives (containing pine and spruce resin, acacia gum and birch tar; beeswax and additives like charcoal, flax or ochre), (2) a blind test on experimental samples to test the reliability of the method and to determine the minimal quantity necessary for analysis, and (3) the analysis of different Palaeolithic adhesives and of experimental samples of at least 15 years old. The analysis was done on extracted and non-extracted adhesives. A unique chromatographic fingerprint was obtained for all experimental adhesive samples. The VOC profile of these adhesives proved to be extremely complex and therefore benefitted significantly from multidimensional separation techniques. GC×GC-HRTOFMS provided an optimal chromatographic separation of adhesive components. HRTOFMS data was used in order to obtain high-resolution mass spectral data to contribute to compound identification. Our study demonstrates that GC×GC-HRTOFMS is a well suited method for identifying small quantities of compound adhesives with significant potential for Palaeolithic contexts. The additional sensitivity afforded by this technique in comparison to traditional GC-MS is a substantial benefit for these quantities. Furthermore, by only analyzing the VOCs of the adhesives, these rare archeological samples are not destroyed and can still be used for other types of analysis. [1] L. Wadley, ‘Compound-Adhesive Manufacture as a Behavioral Proxy for Complex Cognition in the Middle Stone Age’, Curr. Anthropol., vol. 51, no. s1, pp. S111–S119, Jun. 2010. [2] L. Barham, From Hand to Handle: The First Industrial Revolution. Oxford: Oxford University Press, 2013. [3] P. P. A. Mazza, F. Martini, B. Sala, M. Magi, M. P. Colombini, G. Giachi, F. Landucci, C. Lemorini, F. Modugno, and E. Ribechini, ‘A new Palaeolithic discovery: tar-hafted stone tools in a European Mid-Pleistocene bone-bearing bed’, J. Archaeol. Sci., vol. 33, no. 9, pp. 1310–1318, Sep. 2006. [4] M. Regert, ‘Investigating the history of prehistoric glues by gas chromatography-mass spectrometry.’, J. Sep. Sci., vol. 27, no. 3, pp. 244–54, Feb. 2004. [less ▲]

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See detailPostmortem Internal Gas Reservoir Monitoring Using GCxGC-HRTOFMS
Stefanuto, Pierre-Hugues ULg; Perrault, Katelynn ULg; Grabher, Silke et al

in separations (2016), 3(24),

Forensic investigations often require postmortem examination of a body. However, the collection of evidence during autopsy is often destructive, meaning that the body can no longer be examined in its ... [more ▼]

Forensic investigations often require postmortem examination of a body. However, the collection of evidence during autopsy is often destructive, meaning that the body can no longer be examined in its original state. In order to obtain an internal image of the body, whole body postmortem computed tomography (PMCT) has proven to be a valuable non-destructive tool and is currently used in medicolegal centers. PMCT can also be used to visually locate gas reservoirs inside a cadaver, which upon analysis can provide useful information regarding very volatile compounds that are produced after death. However, the non-targeted profiling of all potential volatile organic compounds (VOCs) present in these reservoirs has never been attempted. The aim of this study was to investigate the VOC profile of these reservoirs and to evaluate potential uses of such information to document circumstances surrounding death, cause of death and body taphonomy. Comprehensive two-dimensional gas chromatography coupled to time-of-flight high-resolution mass spectrometry (GC GC-HRTOF-MS) was used for VOC measurements. This study demonstrated that the chemical composition of VOCs within the gas reservoirs differed between locations within a single body but also between individuals. In the future, this work could be expanded to investigate a novel, non-destructive cadaver screening approach prior to full autopsy procedures. [less ▲]

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See detailExploring variable electron ionization for forensic blood VOC profiling
Dubois, Lena ULg; Perrault, Katelynn ULg; Stefanuto, Pierre-Hugues ULg et al

Scientific conference (2016, July 07)

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See detailTime travelling into human prehistory using GC×GC-TOFMS
Perrault, Katelynn ULg; Dubois, Lena ULg; Stefanuto, Pierre-Hugues ULg et al

Scientific conference (2016, July 07)

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See detailStatistical comparisons of beer types using GC×GC-HRTOFMS
Stefanuto, Pierre-Hugues ULg; Dubois, Lena ULg; Perrault, Katelynn ULg et al

Scientific conference (2016, June 02)

Detailed reference viewed: 47 (20 ULg)