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Decleer M, Jovanovic J, Vakula A, Udovicki B, Agoua RSEK, Madder A, De Saeger S, Rajkovic A. Oxygen Consumption Rate Analysis of Mitochondrial Dysfunction Caused by Bacillus cereus Cereulide in Caco-2 and HepG2 Cells. Toxins (Basel) 2018; 10:E266. [PMID: 30004412 PMCID: PMC6070949 DOI: 10.3390/toxins10070266] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 06/20/2018] [Accepted: 06/22/2018] [Indexed: 12/28/2022] Open
Abstract
The emetic syndrome of Bacillus cereus is a food intoxication caused by cereulide (CER) and manifested by emesis, nausea and in most severe cases with liver failure. While acute effects have been studied in the aftermath of food intoxication, an exposure to low doses of cereulide might cause unnoticed damages to the intestines and liver. The toxicity which relies on the mitochondrial dysfunction was assessed on Caco-2 and HepG2 cells after exposure of one, three and ten days to a range of low doses of cereulide. Oxygen consumption rate analyses were used to study the impact of low doses of CER on the bioenergetics functions of undifferentiated Caco-2 and HepG2 cells using Seahorse XF extracellular flux analyzer. Both Caco-2 and HepG2 cells experienced measurable mitochondrial impairment after prolonged exposure of 10 days to 0.25 nM of cereulide. Observed mitochondrial dysfunction was greatly reflected in reduction of maximal cell respiration. At 0.50 nM CER, mitochondrial respiration was almost completely shut down, especially in HepG2 cells. These results corresponded with a severe reduction in the amount of cells and an altered morphology, observed by microscopic examination of the cells. Accurate and robust quantification of basal respiration, ATP production, proton leak, maximal respiration, spare respiratory capacity, and non-mitochondrial respiration allowed better understanding of the effects of cereulide in underlying respiratory malfunctions in low-dose exposure.
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Affiliation(s)
- Marlies Decleer
- Department of Food Technology, Food Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
- Laboratory of Food Analysis, Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
| | - Jelena Jovanovic
- Department of Food Technology, Food Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
| | - Anita Vakula
- Department of Food Preservation Engineering, Faculty of Technology, University of Novi Sad, Bulevar Cara Lazara 1, 21000 Novi Sad, Serbia.
| | - Bozidar Udovicki
- Department of Food Safety and Food Quality Management, Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11081 Zemun-Belgrade, Serbia.
| | - Rock-Seth E K Agoua
- Department of Food Technology, Food Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
| | - Annemieke Madder
- Department of Organic and Macromolecular Chemistry, Organic and Biomimetic Chemistry Research Group, Faculty of Sciences, Campus Sterre, Krijgslaan 281, Building S4, 9000 Gent, Belgium.
| | - Sarah De Saeger
- Laboratory of Food Analysis, Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
| | - Andreja Rajkovic
- Department of Food Technology, Food Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
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McHugh AJ, Feehily C, Hill C, Cotter PD. Detection and Enumeration of Spore-Forming Bacteria in Powdered Dairy Products. Front Microbiol 2017; 8:109. [PMID: 28197144 PMCID: PMC5281614 DOI: 10.3389/fmicb.2017.00109] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 01/16/2017] [Indexed: 01/28/2023] Open
Abstract
With the abolition of milk quotas in the European Union in 2015, several member states including Ireland, Luxembourg, and Belgium have seen year on year bi-monthly milk deliveries to dairies increase by up to 35%. Milk production has also increased outside of Europe in the past number of years. Unsurprisingly, there has been a corresponding increased focus on the production of dried milk products for improved shelf life. These powders are used in a wide variety of products, including confectionery, infant formula, sports dietary supplements and supplements for health recovery. To ensure quality and safety standards in the dairy sector, strict controls are in place with respect to the acceptable quantity and species of microorganisms present in these products. A particular emphasis on spore-forming bacteria is necessary due to their inherent ability to survive extreme processing conditions. Traditional microbiological detection methods used in industry have limitations in terms of time, efficiency, accuracy, and sensitivity. The following review will explore the common spore-forming bacterial contaminants of milk powders, will review the guidelines with respect to the acceptable limits of these microorganisms and will provide an insight into recent advances in methods for detecting these microbes. The various advantages and limitations with respect to the application of these diagnostics approaches for dairy food will be provided. It is anticipated that the optimization and application of these methods in appropriate ways can ensure that the enhanced pressures associated with increased production will not result in any lessening of safety and quality standards.
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Affiliation(s)
- Aoife J McHugh
- Food Bioscience Department, Teagasc Food Research CentreCork, Ireland; School of Microbiology, University College CorkCork, Ireland
| | - Conor Feehily
- Food Bioscience Department, Teagasc Food Research CentreCork, Ireland; APC Microbiome InstituteCork, Ireland
| | - Colin Hill
- School of Microbiology, University College CorkCork, Ireland; APC Microbiome InstituteCork, Ireland
| | - Paul D Cotter
- Food Bioscience Department, Teagasc Food Research CentreCork, Ireland; APC Microbiome InstituteCork, Ireland
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Rajkovic A, Grootaert C, Butorac A, Cucu T, Meulenaer BD, van Camp J, Bracke M, Uyttendaele M, Bačun-Družina V, Cindrić M. Sub-emetic toxicity of Bacillus cereus toxin cereulide on cultured human enterocyte-like Caco-2 cells. Toxins (Basel) 2014; 6:2270-90. [PMID: 25093386 PMCID: PMC4147582 DOI: 10.3390/toxins6082270] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 07/18/2014] [Accepted: 07/22/2014] [Indexed: 12/16/2022] Open
Abstract
Cereulide (CER) intoxication occurs at relatively high doses of 8 µg/kg body weight. Recent research demonstrated a wide prevalence of low concentrations of CER in rice and pasta dishes. However, the impact of exposure to low doses of CER has not been studied before. In this research, we investigated the effect of low concentrations of CER on the behavior of intestinal cells using the Caco-2 cell line. The MTT (mitochondrial 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and the SRB (sulforhodamine B) reactions were used to measure the mitochondrial activity and cellular protein content, respectively. Both assays showed that differentiated Caco-2 cells were sensitive to low concentrations of CER (in a MTT reaction of 1 ng/mL after three days of treatment; in an SRB reaction of 0.125 ng/mL after three days of treatment). Cell counts revealed that cells were released from the differentiated monolayer at 0.5 ng/mL of CER. Additionally, 0.5 and 2 ng/mL of CER increased the lactate presence in the cell culture medium. Proteomic data showed that CER at a concentration of 1 ng/mL led to a significant decrease in energy managing and H2O2 detoxification proteins and to an increase in cell death markers. This is amongst the first reports to describe the influence of sub-emetic concentrations of CER on a differentiated intestinal monolayer model showing that low doses may induce an altered enterocyte metabolism and membrane integrity.
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Affiliation(s)
- Andreja Rajkovic
- Laboratory of Food Microbiology and Food Preservation, Ghent University, Ghent B-9000, Belgium; E-Mail:
| | - Charlotte Grootaert
- Laboratory of Food Chemistry and Human Nutrition, Ghent University, Ghent B-9000, Belgium; E-Mails: (C.G.); (T.C.); (B.D.M.); (J.C.)
| | - Ana Butorac
- Laboratory for Biology and Microbial Genetics, Faculty of Food Technology and Biotechnology, Zagreb University, Zagreb HR-10000, Croatia; E-Mails: (A.B.); (V.B.-D.)
| | - Tatiana Cucu
- Laboratory of Food Chemistry and Human Nutrition, Ghent University, Ghent B-9000, Belgium; E-Mails: (C.G.); (T.C.); (B.D.M.); (J.C.)
| | - Bruno De Meulenaer
- Laboratory of Food Chemistry and Human Nutrition, Ghent University, Ghent B-9000, Belgium; E-Mails: (C.G.); (T.C.); (B.D.M.); (J.C.)
| | - John van Camp
- Laboratory of Food Chemistry and Human Nutrition, Ghent University, Ghent B-9000, Belgium; E-Mails: (C.G.); (T.C.); (B.D.M.); (J.C.)
| | - Marc Bracke
- Laboratory of Experimental Cancer Research, University Hospital Ghent, Ghent B-9000, Belgium; E-Mail:
| | - Mieke Uyttendaele
- Laboratory of Food Microbiology and Food Preservation, Ghent University, Ghent B-9000, Belgium; E-Mail:
| | - Višnja Bačun-Družina
- Laboratory for Biology and Microbial Genetics, Faculty of Food Technology and Biotechnology, Zagreb University, Zagreb HR-10000, Croatia; E-Mails: (A.B.); (V.B.-D.)
| | - Mario Cindrić
- Laboratory for System Biomedicine and Centre for Proteomics and Mass Spectrometry, “Ruđer Bošković” Institute, Zagreb HR-10000, Croatia; E-Mail:
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Veiga T, Nijland JG, Driessen AJM, Bovenberg RAL, Touw H, van den Berg MA, Pronk JT, Daran JM. Impact of velvet complex on transcriptome and penicillin G production in glucose-limited chemostat cultures of a β-lactam high-producing Penicillium chrysogenum strain. OMICS : A JOURNAL OF INTEGRATIVE BIOLOGY 2012; 16:320-33. [PMID: 22439693 PMCID: PMC3369278 DOI: 10.1089/omi.2011.0153] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The multicomponent global regulator Velvet complex has been identified as a key regulator of secondary metabolite production in Aspergillus and Penicillium species. Previous work indicated a massive impact of PcvelA and PclaeA deletions on penicillin production in prolonged batch cultures of P. chrysogenum, as well as substantial changes in transcriptome. The present study investigated the impact of these mutations on product formation and genome-wide transcript profiles under glucose-limited aerobic conditions, relevant for industrial production of β-lactams. Predicted amino acid sequences of PcVelA and PcLaeA in this strain were identical to those in its ancestor Wisconsin54-1255. Controls were performed to rule out transformation-associated loss of penicillin-biosynthesis clusters. The correct PcvelA and PclaeA deletion strains revealed a small reduction of penicillin G productivity relative to the reference strain, which is a much smaller reduction than previously reported for prolonged batch cultures of similar P. chrysogenum mutants. Chemostat-based transcriptome analysis yielded only 23 genes with a consistent differential response in the PcvelAΔ and PclaeAΔ mutants when grown in the absence of the penicillin G side-chain precursor phenylacetic acid. Eleven of these genes belonged to two small gene clusters, one of which contained a gene with high homology to the aristolochene synthase. These results provide a clear caveat that the impact of the Velvet complex on secondary metabolism in filamentous fungi is strongly context dependent.
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Affiliation(s)
- Tânia Veiga
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
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Popoff MR, Poulain B. Bacterial toxins and the nervous system: neurotoxins and multipotential toxins interacting with neuronal cells. Toxins (Basel) 2010; 2:683-737. [PMID: 22069606 PMCID: PMC3153206 DOI: 10.3390/toxins2040683] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2010] [Revised: 03/18/2010] [Accepted: 04/07/2010] [Indexed: 12/13/2022] Open
Abstract
Toxins are potent molecules used by various bacteria to interact with a host organism. Some of them specifically act on neuronal cells (clostridial neurotoxins) leading to characteristics neurological affections. But many other toxins are multifunctional and recognize a wider range of cell types including neuronal cells. Various enterotoxins interact with the enteric nervous system, for example by stimulating afferent neurons or inducing neurotransmitter release from enterochromaffin cells which result either in vomiting, in amplification of the diarrhea, or in intestinal inflammation process. Other toxins can pass the blood brain barrier and directly act on specific neurons.
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Affiliation(s)
- Michel R. Popoff
- Neurotransmission et Sécrétion Neuroendocrine, CNRS UPR 2356 IFR 37 - Neurosciences, Centre de Neurochimie, 5, rue Blaise Pascal, F-67084 STRASBOURG cedex, France;
- Author to whom correspondence should be addressed;
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Parvathi A, Krishna K, Jose J, Joseph N, Nair S. Biochemical and molecular characterization of Bacillus pumilus isolated from coastal environment in Cochin, India. Braz J Microbiol 2009; 40:269-75. [PMID: 24031357 PMCID: PMC3769717 DOI: 10.1590/s1517-838220090002000012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 07/10/2008] [Accepted: 02/26/2009] [Indexed: 11/22/2022] Open
Abstract
Bacillus species constitute a diverse group of bacteria widely distributed in soil and the aquatic environment. In this study, Bacillus strains isolated from the coastal environment of Cochin, India were identified by detailed conventional biochemical methods, fatty acid methyl ester (FAME) analysis and partial 16S rDNA sequencing. Analysis of the data revealed that Bacillus pumilus was the most predominant species in the region under study followed by B. cereus and B. sphaericus. The B. pumilus isolates were further characterized by arbitrarily primed PCR (AP-PCR), antibiotic sensitivity profiling and PCR screening for known toxin genes associated with Bacillus spp. All B. pumilus isolates were biochemically identical, exhibited high protease and lipase activity and uniformly sensitive to antibiotics tested in this study. One strain of B. pumilus harboured cereulide synthetase gene cesB of B. cereus which was indistinguishable from rest of the isolates biochemically and by AP-PCR. This study reports, for the first time, the presence of the emetic toxin gene cesB in B. pumilus.
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Affiliation(s)
- Ammini Parvathi
- Department of Biological Oceanography, National Institute of Oceanography, Regional Center , Cochin - 682 018 , India
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Identification of Bacillus cereus group species associated with food poisoning outbreaks in British Columbia, Canada. Appl Environ Microbiol 2008; 74:7451-3. [PMID: 18849447 DOI: 10.1128/aem.01284-08] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Food poisoning laboratories identify Bacillus cereus using routine methods that may not differentiate all Bacillus cereus group species. We recharacterized Bacillus food-poisoning strains from 39 outbreaks and identified B. cereus in 23 outbreaks, B. thuringiensis in 4, B. mycoides in 1, and mixed strains of Bacillus in 11 outbreaks.
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Cheng YQ. Deciphering the biosynthetic codes for the potent anti-SARS-CoV cyclodepsipeptide valinomycin in Streptomyces tsusimaensis ATCC 15141. Chembiochem 2006; 7:471-7. [PMID: 16511823 PMCID: PMC7162017 DOI: 10.1002/cbic.200500425] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Indexed: 11/27/2022]
Abstract
Valinomycin was recently reported to be the most potent agent against severe acute respiratory-syndrome coronavirus (SARS-CoV) in infected Vero E6 cells. Aimed at generating analogues by metabolic engineering, the valinomycin biosynthetic gene cluster has been cloned from Streptomyces tsusimaensis ATCC 15141. Targeted disruption of a nonribosomal peptide synthetase (NRPS) gene abolishes valinomycin production, which confirms its predicted nonribosomal-peptide origin. Sequence analysis of the NRPS system reveals four distinctive modules, two of which contain unusual domain organizations that are presumably involved in the generation of biosynthetic precursors D-alpha-hydroxyisovaleric acid and L-lactic acid. The respective adenylation domains in these two modules contain novel substrate-specificity-conferring codes that might specify for a class of hydroxyl acids for the biosynthesis of the depsipeptide natural products.
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Affiliation(s)
- Yi-Qiang Cheng
- Department of Biological Sciences, Biotechnology Program, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
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Ehling-Schulz M, Vukov N, Schulz A, Shaheen R, Andersson M, Märtlbauer E, Scherer S. Identification and partial characterization of the nonribosomal peptide synthetase gene responsible for cereulide production in emetic Bacillus cereus. Appl Environ Microbiol 2005; 71:105-13. [PMID: 15640177 PMCID: PMC544239 DOI: 10.1128/aem.71.1.105-113.2005] [Citation(s) in RCA: 194] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cereulide, a depsipeptide structurally related to valinomycin, is responsible for the emetic type of gastrointestinal disease caused by Bacillus cereus. Due to its chemical structure, (D-O-Leu-D-Ala-L-O-Val-L-Val)(3), cereulide might be synthesized nonribosomally. Therefore, degenerate PCR primers targeted to conserved sequence motifs of known nonribosomal peptide synthetase (NRPS) genes were used to amplify gene fragments from a cereulide-producing B. cereus strain. Sequence analysis of one of the amplicons revealed a DNA fragment whose putative gene product showed significant homology to valine activation NRPS modules. The sequences of the flanking regions of this DNA fragment revealed a complete module that is predicted to activate valine, as well as a putative carboxyl-terminal thioesterase domain of the NRPS gene. Disruption of the peptide synthetase gene by insertion of a kanamycin cassette through homologous recombination produced cereulide-deficient mutants. The valine-activating module was highly conserved when sequences from nine emetic B. cereus strains isolated from diverse geographical locations were compared. Primers were designed based on the NRPS sequence, and the resulting PCR assay, targeting the ces gene, was tested by using a panel of 143 B. cereus group strains and 40 strains of other bacterial species showing PCR bands specific for only the cereulide-producing B. cereus strains.
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Affiliation(s)
- Monika Ehling-Schulz
- Microbial Ecology Group, Department of Biosciences, WZW, Technische Universität München, D-85354 Freising, Germany
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