Papers by Jose Diana Di Mavungu
Journal of Chromatography A, Jul 1, 2011
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
play key roles in signal transduction and cell regulation, probably during the keratinization of ... more play key roles in signal transduction and cell regulation, probably during the keratinization of human hair. Current methods using mass spectrometry (MS), however, are not sufficient to allow the comprehensive analysis of CER molecules, including isobaric and isomeric CERs. Therefore, a method for the comprehensive profiling of CERs was developed. The method developed is based on reversed-phase liquid chromatography (RPLC) coupled to atmospheric pressure chemical ionization (APCI)-MS. Comprehensive identification and profiling of CERs is achieved using two sets of multimass chromatograms obtained from two channel detections that monitor both molecular-related and sphingoid-related ions under two different in-source collision-induced dissociation conditions and using retention times obtained from RPLC. The application of this method revealed that human hair contains 73 species of CER molecules, which were all corroborated by structural analysis using tandem mass spectrometry. The results further revealed that the composition is characterized by predominant molecules consisting of even carbon atom-containing saturated/unsaturated nonhydroxy or a-hydroxy fatty acids and C 18 dihydrosphingosine, a minor but distinct content of isobaric/isomeric and odd chain-containing CERs. This successfully developed RPLC-APCI-MS technique allows the comprehensive profiling of CER molecules in hair for the investigation of their physicochemical and physiological roles.-Masukawa, Y., H. Tsujimura, and H. Narita. Liquid chromatography-mass spectrometry for comprehensive profiling of ceramide molecules in human hair.
Mycotoxins are secondary metabolites produced by fungi. When these fungi are present on agricultu... more Mycotoxins are secondary metabolites produced by fungi. When these fungi are present on agricultural commodities, they can pose a high risk to animal and human health. As the European Commission imposes strict regulations on maximum levels of several mycotoxins, it is a prerequisite for farmers to meet these regulations to avoid complete loss of a contaminated batch. In an agro-ecosystem, farmers try to avoid fungal infection and the occurrence of mycotoxins in their commodities via prevention and intervention approaches, but often fail in completely eliminating the risk. Therefore, detoxification strategies are needed such as the use of binders or microorganisms able to detoxify these mycotoxins. Our project focuses on the microbial detoxification of deoxynivalenol (DON), a worldwide prevalent mycotoxin. Bacteria were screened from natural environments for their DON-detoxification capacity in minimal medium through HPLC-UV and non-targeted LC-MS/MS. Furthermore, the residual toxicity was measured with a bioassay using the aquatic bio-indicator plant Lemna minor. Pursuing this approach, two mixed cultures were obtained, originating from soil and activated sludge, capable of converting DON into the epimer of DON and the epimer of DOM-1, both conveying no residual toxicity for the Lemna minor plant.
World Mycotoxin Journal, 2014
Nowadays, complaints about poor indoor air quality have become common. The variety of indoor air ... more Nowadays, complaints about poor indoor air quality have become common. The variety of indoor air health problems include chronic fatigue, allergy, skin and eye irritation, and can be caused by several factors including fungi and their metabolites present in a building. The objective of this study was to establish a method for untargeted analysis of secondary fungal metabolites in indoor environments. As a detection technique, time-of-flight mass spectrometry was chosen, as it provided mass accuracy and higher sensitivity in full scan acquisition mode compared to tandem mass spectrometers. The method was first applied to fungal cultures, namely Penicillium brevicompactum and Chaetomium murorum, which were isolated from mouldy houses and grown on building materials under laboratory conditions for 7-21 days. Following the proposed strategy based on accurate mass measurement and post-acquisition data processing using principal component analysis, roquefortine C, brevianamide A and mycophenolic acid were identified in Penicillium sp., while chaetoglobosin A was found to be produced by Chaetomium sp. Subsequently, samples from mouldy inhabited buildings were analysed using the developed method. The actual presence of meleagrin was demonstrated in mouldy indoor environment. Applying the method to air and dust samples collected in these mouldy buildings, no metabolites were detected possibly due to generally low concentrations in these types of samples.
Journal of Chromatography A, Dec 1, 2012
Saeger (2012). Improved positive electrospray ionization of patulin by adduct formation: Usefulne... more Saeger (2012). Improved positive electrospray ionization of patulin by adduct formation: Usefulness in liquid chromatography-tandem mass spectrometry multi-mycotoxin analysis.
Environment International, Jul 1, 2013
This study was conducted to investigate mycotoxin exposure in children (n=220, aged 1.5-4.5 years... more This study was conducted to investigate mycotoxin exposure in children (n=220, aged 1.5-4.5 years) from high mycotoxin contamination regions of Cameroon and to examine the association between the mycotoxin levels (in total 18 analytes) and several socio-demographic factors and anthropometric characteristics. A cross-sectional study was conducted in six villages in Cameroon with 220 children. Mycotoxins and their metabolites were detected in 160/220 (73%) urine samples. There were significant differences in the mean contamination levels of ochratoxin A (p = 0.01) and β-zearalenol (p = 0.017) between the two agro-ecological zones investigated. Likewise significant differences were observed in the mean levels of aflatoxin M 1 (p = 0.001) across the weaning categories of these children. The mean concentration of aflatoxin M 1 detected in the urine of the partially breastfed children (1.43 ng/mL) was significantly higher (p = 0.001) than those of the fully weaned children (0.282 ng/mL). Meanwhile, the mean concentrations of deoxynivalenol (3.0 ng/mL) and fumonisin B 1 (0.59 ng/mL) detected in the urine of the male children was significantly (p value 0.021 for deoxynivalenol and 0.004 for fumonisin B 1) different from the levels detected in the urine of female children; 0.71 ng/mL and 0.01 ng/mL for deoxynivalenol and fumonisin B 1 respectively. In this study, there was no association between the different malnutrition categories (stunted, wasting and underweight) and the mycotoxin concentrations detected in the urine of these children. However, there is sufficient evidence to suggest that children in Cameroon under the age 5 are exposed to high levels of carcinogenic substances such as fumonisin B 1 , aflatoxin M 1 and ochratoxin A through breastfeeding. To the best of our knowledge, this is the first report of its kind carried out in West Africa to determine multi-mycotoxin exposure in infants.
John Wiley & Sons, Ltd eBooks, Jan 30, 2015
Patulin is a mycotoxin produced by several fungal species, mainly by Penicillium spp. and Aspergi... more Patulin is a mycotoxin produced by several fungal species, mainly by Penicillium spp. and Aspergillus spp. Since patulin-producing fungi are widely spread, this toxin has been detected in food (fruit-and vegetablebased products, cereal products, cheese), feed and even in mouldy waterdamaged dwellings. Co-occurrence of patulin with other mycotoxins has also been reported. The aim of the current study was the optimisation of the electrospray ionization of patulin in positive mode (ESI+) with the view of a concomitant LC-MS/MS analysis with other mycotoxins.
Microorganisms, May 11, 2020
Two fungi, i.e., Aspergillus flavus Link and Aspergillus oryzae (Ahlb.) E. Cohn, were cultivated ... more Two fungi, i.e., Aspergillus flavus Link and Aspergillus oryzae (Ahlb.) E. Cohn, were cultivated according to two methodologies, namely submerged and biofilm cultures with the primary aim to use their secondary metabolites the supernatant CL 50 , and CL 90 varied between 1.3% (v/v) to 12.7% (v/v) for incubation times from 24 to 72 h. While the A. flavus supernatant entomotoxicity was higher than this of A. oryzae, the biofilm culture application increased the efficiency of the former. Proteomic analysis of the supernatants revealed discrepancies among the two species and modes of cultivation. Furthermore, the secondary metabolite profiles of both Aspergillus cultures were verified. Aspergillic acid, beta-cyclopiazonic acid, cyclopiazonic acid, ferrineospergillin, flavacol, and spermadin A were most predominant. Generally, these secondary metabolites were present in higher concentrations in the supernatants of A. flavus and biofilm cultures. These molecular identifications correlated positively with entomotoxic activity. Noteworthy, the absence of carcinogenic aflatoxins was remarkable, and it will allow further valorization to produce A. flavus to develop potential biopesticides.
World Mycotoxin Journal, 2014
The manuscript details the development of an in vitro model plant system using detached leaves be... more The manuscript details the development of an in vitro model plant system using detached leaves because there is a need for biosynthetic methods for the production and isolation of masked mycotoxins. This detached leaf in vitro model was firstly applied to deoxynivalenol with satisfying results. The biosynthesis of deoxynivalenol-3-glucoside was confirmed using its respective commercially available reference standard. The detached leaf in vitro model was also secondly applied to T-2 toxin. Mono-and tri-glucoside derivatives of T-2 toxin and HT-2 toxin, T-2-(3)-glucoside, T-2-(3)-triglucoside and HT-2-(3)-glucoside were identified and characterized using Orbitrap high-resolution mass spectrometry. This is the first report on a triglucoside of T-2 toxin. The discovery of new masked forms implies the importance of the development of analytical methods for their detection, the constitution of toxicity studies, and proving the relevance of presence in the food and feed chain.
World Mycotoxin Journal, May 1, 2013
A rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the d... more A rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of ergot alkaloids in buffered solutions from in vitro studies. The method implied a liquid-liquid extraction of the analytes under alkaline conditions prior to LC-MS/MS analysis and resulted in good recovery (91-123%) of the six ergot alkaloids defined by the European Food Safety Authority as most important, namely ergometrine, ergosine, ergotamine, ergocornine, ergokryptine and ergocristine, as well as their corresponding epimers. The method also proved to be sensitive, repeatable, linear, accurate and robust. Furthermore, the method was applied to evaluate the in vitro binding efficacy of a clay-based mycotoxin binder towards ergometrine, ergosine and ergocornine, through a design encompassing pH 3.0 and 6.8 to mimic the digestive tract. The binder demonstrated binding efficacy of 24, 93 and 97%, respectively, for these ergot alkaloids.
Analytical and Bioanalytical Chemistry, Mar 9, 2017
An analytical strategy based on a hybrid quadrupole-Orbitrap mass spectrometry was proposed for t... more An analytical strategy based on a hybrid quadrupole-Orbitrap mass spectrometry was proposed for the simultaneous screening of known destruxins and characterization of potential members of this class of secondary metabolites, in order to evaluate the metabolite production of entomopathogenic fungi used as biocontrol agents. Initially, the fragmentation pathway of the known and commercially available destruxin A was established combining high resolution mass spectrometry (HRMS) and multiple stage MS data in order to obtain the strategy for the characterization of other destruxins for which reference standards were not available. Nineteen known destruxins including A
Talanta, 2014
A holistic approach based on high resolution and multiple stage mass spectrometry was developed f... more A holistic approach based on high resolution and multiple stage mass spectrometry was developed for identification of less studied or novel ergot alkaloid derivatives. Initially, the fragmentation of nine known ergot alkaloids was studied to establish a strategy for the identification of novel ergot alkaloids. Ions with m/z 223 and m/z 251 were found to be common for all ergopeptines, ergoamides and ergopeptams. Subsequently, parent scan experiments using these ions were performed to screen grain samples for the presence of possible ergot alkaloid derivatives. Besides the six most common ergot alkaloids and their corresponding epimers (for which reference standards were available), eleven other ergot alkaloid derivatives were identified following the proposed strategy.
Food Additives & Contaminants: Part A, Jan 2, 2014
Journal of Chromatography A, Dec 1, 2018
An ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI+/--MS/... more An ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI+/--MS/MS) method for the simultaneous analysis of citrinin (CIT) and ochratoxin A (OTA) in feed (chicken and pig) and food (cereal-based products, fruit, vegetable juices, nuts, seeds, herbs, spices, vegetarian and soy products, alcoholic beverages, baby food products and food supplements) was developed. The mycotoxins were extracted from these matrices using a QuEChERS-based extraction method without any further clean-up step. The samples were 5-fold concentrated. Final extracts were analyzed using a UPLC-MS/MS system and chromatographic separation was achieved by applying a gradient elution for a total run time of 10 min. Mycotoxins were quantified using an internal calibration via analyte/13C-labeled internal standard ratio. The developed method was validated according to the criteria described in Commission Regulation No. 401/2006/EC and Commission Decision No. 2002/657/EC. Specificity, linearity, apparent recovery, limit of detection and quantification, intraday and interday precision, measurement uncertainty, matrix effect, and extraction efficiency were the parameters studied. Finally, 90 Belgian chicken and pig feed samples were analyzed, revealing the simultaneous presence of CIT (
Environmental Pollution, May 1, 2019
This study was conducted to investigate mycotoxin exposure in 260 rural residents (age 18-66 year... more This study was conducted to investigate mycotoxin exposure in 260 rural residents (age 18-66 years) in Nanjing, China. Paired plasma and first morning urine samples were analyzed for 26 mycotoxin biomarkers, including parent mycotoxins and 14 mycotoxin metabolites, by an ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method. Mycotoxins and their metabolites were detected in 95/260 (36.5%) plasma samples and 144/260 (55.4%) urine samples. The most prevalent mycotoxin in plasma was ochratoxin A (OTA), with the incidence of 27.7% (range 0.312-9.18 µg/L), while aflatoxin B 1-lysine (AFB 1-lysine) (incidence 19.6%, range 10.5-74.5 pg/mg albumin), fumonisin B 1 (FB 1) (incidence 2.7%, range 0.305-0.993 µg/L), deoxynivalenol (DON) (incidence 2.3%, range 1.39-5.53 µg/L), zearalenone (ZEN) (incidence 6.5%, range 0.063-0.418 µg/L) and zearalanone (ZAN) (incidence 1.2%, range 0.164-0.346 µg/L) were also detected in plasma samples. Deoxynivalenol-15-glucuronide (DON-15-GlcA) was the most frequently detected urinary mycotoxin, with the incidence of 43.8% (range 0.828-37.7 µg/L). DON (incidence 10.0%, range 1.39-14.7 µg/L), DON-3-glucuronide (DON-3-GlcA) (incidence 15.8%, range 0.583-5.84 µg/L), aflatoxin M 1 (AFM 1) (incidence 10.4%, range 0.125-0.464 µg/L), ZAN (incidence 7.7%, range 0.106-1.82 µg/L), ZEN (incidence 6.9%, range 0.056-0.311 µg/L), FB 1 (incidence 3.1%, range 0.230-1.33 µg/L), T-2 toxin (incidence 2.3%, range 0.248-3.61 µg/L) and OTA (incidence 1.2%, range 0.153-0.557 µg/L) were also found in urine samples. Based on the plasma or urinary levels, the daily intakes of AFB 1 , FB 1 , ZEN, DON and OTA were estimated.
Journal of Chromatography A, Dec 1, 2014
A UPLC-ESI +/−-MS/MS method for the simultaneous determination of free (alternariol, alternariol ... more A UPLC-ESI +/−-MS/MS method for the simultaneous determination of free (alternariol, alternariol monomethyl ether, altenuene, tenuazonic acid, tentoxin, altertoxin-I) and conjugated (sulfates and glucosides of alternariol and alternariol monomethyl ether) Alternaria toxins in cereals and cereal products (rice, oat flakes and barley) was developed. Optimization of the sample preparation and extraction methodology was achieved through experimental design, using full factorial design for extraction solvent composition optimization and fractional factorial design to identify the critical factors in the sample preparation protocol, which were in turn subjected to optimization. Final extracts were analysed using an Waters Acquity UPLC system coupled to a Quattro Premier XE mass spectrometer equipped with an electrospray interface operated in both positive and negative ionization mode. Chromatographic separation was achieved using an Acquity UPLC HSS T3 column, and the applied gradient elution programme allowed for the simultaneous determination of 10 Alternaria toxins in a one-step chromatographic run with a total run time of only 7 min. Subsequently, the method, applying isotopically labelled internal standards ([ 2 H 4 ]-alternariol monomethyl ether and [ 13 C 6 , 15 N]-tenuazonic acid), was validated for several parameters such as linearity, apparent recovery, limit of detection, limit of quantification, precision, measurement uncertainty and specificity (in agreement with the criteria mentioned in Commission Regulation No. 401/2006/EC and Commission Decision No. 2002/657/EC). During validation, quality of the bioanalytical data was improved by counteracting the observed heteroscedasticity through the application of weighted least squares linear regression (WLSLR). Finally, 24 commercially available cereal-based foodstuffs were subjected to analysis, revealing the presence of tenuazonic acid in both rice and oat flake samples (<LOQ-68 ± 7 g kg −1) and tentoxin in rice samples (<LOQ-10.9 ± 2.0 g kg −1).
Analytica Chimica Acta, Sep 1, 2012
Saeger (2012). A direct assessment of mycotoxin biomarkers in human urine samples by liquid chrom... more Saeger (2012). A direct assessment of mycotoxin biomarkers in human urine samples by liquid chromatography tandem mass spectrometry.
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Papers by Jose Diana Di Mavungu