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Jino K, Miyamoto K, Kanbara T, Unemura C, Horiguchi N, Ago Y. Allosteric inhibition of phosphodiesterase 4D induces biphasic memory-enhancing effects associated with learning-activated signaling pathways. Psychopharmacology (Berl) 2024; 241:805-816. [PMID: 38114603 DOI: 10.1007/s00213-023-06510-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 11/20/2023] [Indexed: 12/21/2023]
Abstract
RATIONALE Phosphodiesterase 4D negative allosteric modulators (PDE4D NAMs) enhance memory and cognitive function in animal models without emetic-like side effects. However, the relationship between increased cyclic adenosine monophosphate (cAMP) signaling and the effects of PDE4D NAM remains elusive. OBJECTIVE To investigate the roles of hippocampal cAMP metabolism and synaptic activation in the effects of D159687, a PDE4D NAM, under baseline and learning-stimulated conditions. RESULTS At 3 mg/kg, D159687 enhanced memory formation and consolidation in contextual fear conditioning; however, neither lower (0.3 mg/kg) nor higher (30 mg/kg) doses induced memory-enhancing effects. A biphasic (bell-shaped) dose-response effect was also observed in a scopolamine-induced model of amnesia in the Y-maze, whereas D159687 dose-dependently caused an emetic-like effect in the xylazine/ketamine anesthesia test. At 3 mg/kg, D159687 increased cAMP levels in the hippocampal CA1 region after conditioning in the fear conditioning test, but not in the home-cage or conditioning cage (i.e., context only). By contrast, 30 mg/kg of D159687 increased hippocampal cAMP levels under all conditions. Although both 3 and 30 mg/kg of D159687 upregulated learning-induced Fos expression in the hippocampal CA1 30 min after conditioning, 3 mg/kg, but not 30 mg/kg, of D159687 induced phosphorylation of synaptic plasticity-related proteins such as cAMP-responsive element-binding protein, synaptosomal-associated protein 25 kDa, and the N-methyl-D-aspartate receptor subunit NR2A. CONCLUSIONS Our findings suggest that learning-stimulated conditions can alter the effects of a PDE4D NAM on hippocampal cAMP levels and imply that a PDE4D NAM exerts biphasic memory-enhancing effects associated with synaptic plasticity-related signaling activation.
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Affiliation(s)
- Kohei Jino
- Laboratory for Drug Discovery and Disease Research, Shionogi Pharmaceutical Research Center, Shionogi & Co., Ltd., 3-1-1 Futaba-cho, Toyonaka-shi, Osaka, 561-0825, Japan
- Department of Cellular and Molecular Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Hiroshima, 734-8553, Japan
| | - Keisuke Miyamoto
- Laboratory for Drug Discovery and Disease Research, Shionogi Pharmaceutical Research Center, Shionogi & Co., Ltd., 3-1-1 Futaba-cho, Toyonaka-shi, Osaka, 561-0825, Japan
| | - Tomoe Kanbara
- Laboratory for Drug Discovery and Disease Research, Shionogi Pharmaceutical Research Center, Shionogi & Co., Ltd., 3-1-1 Futaba-cho, Toyonaka-shi, Osaka, 561-0825, Japan
| | - Chie Unemura
- Laboratory for Drug Discovery and Disease Research, Shionogi Pharmaceutical Research Center, Shionogi & Co., Ltd., 3-1-1 Futaba-cho, Toyonaka-shi, Osaka, 561-0825, Japan
| | - Naotaka Horiguchi
- Laboratory for Drug Discovery and Disease Research, Shionogi Pharmaceutical Research Center, Shionogi & Co., Ltd., 3-1-1 Futaba-cho, Toyonaka-shi, Osaka, 561-0825, Japan.
| | - Yukio Ago
- Department of Cellular and Molecular Pharmacology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Hiroshima, 734-8553, Japan.
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Zheng Y, Xu W, Guo H, Yu S, Xue L, Chen M, Zhang J, Xu Z, Wu Q, Wang J, Ding Y. The potential of lactose to inhibit cereulide biosynthesis of emetic Bacillus cereus in milk. Int J Food Microbiol 2024; 411:110517. [PMID: 38096676 DOI: 10.1016/j.ijfoodmicro.2023.110517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 10/07/2023] [Accepted: 12/04/2023] [Indexed: 01/10/2024]
Abstract
This study aims to investigate the potential role of lactose on cereulide biosynthesis by emetic Bacillus cereus in dairy matrices. The cereulide yields in whole milk and lactose-free milk were investigated using the emetic reference strain F4810/72. To eliminate the influence of complex food substrates, the LB medium model was further used to characterize the effect of lactose on cereulide produced by F4810/72 and five other emetic B. cereus strains. Results showed that the lactose-free milk displayed a 13-fold higher amount of cereulide than whole milk, but the cereulide level could be reduced by 91 % when the lactose content was restored. The significant inhibition of lactose on cereulide yields of all tested B. cereus strains was observed in LB medium, showing a dose-dependent manner with inhibition rates ranging of 89-98 %. The growth curves and lactose utilization patterns of all strains demonstrated that B. cereus cannot utilize lactose as a carbon source and lactose might act as a signal molecule to regulate cereulide production. Moreover, lactose strongly repressed the expression of cereulide synthetase genes (ces), possibly by inhibiting the key regulator Spo0A at the transcriptional level. Our findings highlight the potential of lactose as an effective strategy to control cereulide production in food.
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Affiliation(s)
- Yin Zheng
- Department of Food Science & Engineering, Institute of Food Safety and Nutrition, Jinan University, Guangzhou 510632, China
| | - Wenxing Xu
- Department of Food Science & Engineering, Institute of Food Safety and Nutrition, Jinan University, Guangzhou 510632, China; National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Hui Guo
- Department of Food Science & Engineering, Institute of Food Safety and Nutrition, Jinan University, Guangzhou 510632, China
| | - Shubo Yu
- National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Liang Xue
- National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Moutong Chen
- National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Jumei Zhang
- National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Zhenlin Xu
- College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Qingping Wu
- National Health Commission Science and Technology Innovation Platform for Nutrition and Safety of Microbial Food, Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Juan Wang
- College of Food Science, South China Agricultural University, Guangzhou 510642, China.
| | - Yu Ding
- Department of Food Science & Engineering, Institute of Food Safety and Nutrition, Jinan University, Guangzhou 510632, China.
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3
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Leong SS, Korel F, King JH. Bacillus cereus: A review of "fried rice syndrome" causative agents. Microb Pathog 2023; 185:106418. [PMID: 37866551 DOI: 10.1016/j.micpath.2023.106418] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 10/19/2023] [Accepted: 10/19/2023] [Indexed: 10/24/2023]
Abstract
"Fried rice syndrome" originated from the first exposure to a fried rice dish contaminated with Bacillus cereus. This review compiles available data on the prevalence of B. cereus outbreak cases that occurred between 1984 and 2019. The outcome of B. cereus illness varies dramatically depending on the pathogenic strain encounter and the host's immune system. B. cereus causes a self-limiting, diarrheal illness caused by heat-resistant enterotoxin proteins, and an emetic illness caused by the deadly toxin named cereulide. The toxins together with their extrinsic factors are discussed. The possibility of more contamination of B. cereus in protein-rich food has also been shown. Therefore, the aim of this review is to summarize the available data, focusing mainly on B. cereus physiology as the causative agent for "fried rice syndrome." This review emphasizes the prevalence of B. cereus in starchy food contamination and outbreak cases reported, the virulence of both enterotoxins and emetic toxins produced, and the possibility of contaminated in protein-rich food. The impact of emetic or enterotoxin-producing B. cereus on public health cannot be neglected. Thus, it is essential to constantly monitor for B. cereus contamination during food handling and hygiene practices for food product preparation.
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Affiliation(s)
- Sui Sien Leong
- Department of Animal Sciences and Fishery, Faculty of Agricultural and Forestry Sciences, Universiti Putra Malaysia, Nyabau Road, Bintulu, 97008, Sarawak, Malaysia; Institute of Ecosystem Science Borneo, Universiti Putra Malaysia Bintulu Sarawak Campus, Nyabau Road, Bintulu, 97008, Sarawak, Malaysia.
| | - Figen Korel
- Food Engineering Department, Faculty of Engineering, Izmir Institute of Technology, Urla, 35430, İzmir, Turkey
| | - Jie Hung King
- Department of Crop Science, Faculty of Agricultural and Forestry Sciences, Universiti Putra Malaysia, Nyabau Road, Bintulu, 97008, Sarawak, Malaysia
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Wan Y, Yang L, Li Q, Wang X, Zhou T, Chen D, Li L, Wang Y, Wang X. Stability and emetic activity of enterotoxin like X (SElX) with high carrier rate of food poisoning Staphylococcus aureus. Int J Food Microbiol 2023; 404:110352. [PMID: 37549593 DOI: 10.1016/j.ijfoodmicro.2023.110352] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/24/2023] [Accepted: 07/30/2023] [Indexed: 08/09/2023]
Abstract
In order to analyze and clarify the thermal stability of food poisoning Staphylococcus aureus (S. aureus) enterotoxin-like X (SElX) and the biological characteristics of digestive enzymes, and to evaluate the risk of S. aureus carrying selx gene in food poisoning, the selx gene carrying rates of 165 strains isolated from 95 food poisoning events from 2006 to 2019 were first statistically analyzed. Subsequently, the purified recombinant SElX protein was digested and heated, and the superantigen activity was verified with mouse spleen cells and peripheral blood mononuclear cells of kittens. At the same time, the emetic activity and toxicity of SElX were evaluated using the kitten vomiting animal model, mice toxin model and in vitro cell models. The results showed the selx gene carrying rate of 165 food poisoning S. aureus strains was 90.30 %. SElX had significant resistance to heat treatment and pepsin digestion (pH = 4.0 and pH = 4.5), and had good superantigen activity and emetic activity. However, there is no significant lethal effect on mice and no significant toxicity to cells. Importantly, we found that SElX had an inhibitory effect on acidic mucus of goblet cells in various segments of the small intestine. The present study investigated the stability of SElX, and confirmed the emetic activity of SElX by establishing a kitten vomiting model for the first time, suggesting that SElX is a high risk toxin of food poisoning, which will provide new ideas for the prevention and control of S. aureus food poisoning.
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Affiliation(s)
- Yangli Wan
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Liu Yang
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Qianhong Li
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xiaowen Wang
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Ting Zhou
- College of Veterinary Medicine, Northwest A&F University, China
| | - Dishi Chen
- Sichuan Animal Disease Prevention and Control Center, Chengdu 610041, China
| | - Li Li
- Sichuan Animal Disease Prevention and Control Center, Chengdu 610041, China
| | - Yeru Wang
- Risk Assessment Division China National Center for Food Safety Risk Assessment, Chaoyang District, Beijing, China.
| | - Xin Wang
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China.
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Boutonnet C, Ginies C, Alpha-Bazin B, Armengaud J, Château A, Duport C. S-layer is a key element in metabolic response and entry into the stationary phase in Bacillus cereus AH187. J Proteomics 2023; 289:105007. [PMID: 37730087 DOI: 10.1016/j.jprot.2023.105007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 08/21/2023] [Accepted: 09/14/2023] [Indexed: 09/22/2023]
Abstract
Bacillus cereus is a food-borne Gram-positive pathogen. The emetic reference strain B. cereus AH187 is surrounded by a proteinaceous surface layer (S-layer) that contributes to its physico-chemical surface properties, and promotes its adhesion in response to starvation conditions. The S-layer produced by B. cereus AH187 is composed of two proteins, SL2 and EA1, which are incorporated at different growth stages. Here, we showed that deletion of the genes encoding SL2 and EA1 produced viable cells, but decreased the glucose uptake rate at the start of growth, and induced extensive reorganization of the cellular and exoproteomes upon entry into the stationary phase. As a consequence, stationary cells were less resistant to abiotic stress. Taken together, our data indicate that the S-layer is crucial but comes at a metabolic cost that modulates the stationary phase response. SIGNIFICANCE: The emetic strains of Bacillus cereus are known to cause severe food poisoning, making it crucial to understand the factors contributing to their selective enrichment in foods. Most emetic strains are surrounded by a crystalline S-layer, which is a costly protein structure to produce. In this study, we used high-throughput proteomics to investigate how S-layer synthesis affects the allocation of cellular resources in the emetic B. cereus strain AH187. Our results demonstrate that the synthesis of the S-layer plays a crucial role in the pathogen's ability to thrive under stationary growth phase conditions by modulating the stress response, thereby promoting its lifestyle as an emetic pathogen. We conclude that the synthesis of the S-layer is a critical adaptation for emetic B. cereus to successfully colonize specific niches.
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Affiliation(s)
| | | | - Béatrice Alpha-Bazin
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, 30200 Bagnols-sur-Cèze, France
| | - Jean Armengaud
- Université Paris Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, 30200 Bagnols-sur-Cèze, France
| | - Alice Château
- Avignon Université, INRAE, UMR SQPOV, F-84914 Avignon, France
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Abstract
Very different toxins are responsible for the two types of gastrointestinal diseases caused by Bacillus cereus: the diarrhoeal syndrome is linked to nonhemolytic enterotoxin NHE, hemolytic enterotoxin HBL, and cytotoxin K, whereas emesis is caused by the action of the depsipeptide toxin cereulide. The recently identified cereulide synthetase genes permitted development of a molecular assay that targets all toxins known to be involved in food poisoning in a single reaction, using only four different sets of primers. The enterotoxin genes of 49 strains, belonging to different phylogenetic branches of the B. cereus group, were partially sequenced to encompass the molecular diversity of these genes. The sequence alignments illustrated the high molecular polymorphism of B. cereus enterotoxin genes, which is necessary to consider when establishing PCR systems. Primers directed towards the enterotoxin complex genes were located in different CDSs of the corresponding operons to target two toxin genes with one single set of primers. The specificity of the assay was assessed using a panel of B. cereus strains with known toxin profiles and was successfully applied to characterize strains from food and clinical diagnostic labs as well as for the toxin gene profiling of B. cereus isolated from silo tank populations.
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Affiliation(s)
- Monika Ehling-Schulz
- Microbial Ecology Group, Department of Biosciences, WZW, Technische Universität München, Freising, Germany.
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Ehling-Schulz M, Svensson B, Guinebretiere MH, Lindbäck T, Andersson M, Schulz A, Fricker M, Christiansson A, Granum PE, Märtlbauer E, Nguyen-The C, Salkinoja-Salonen M, Scherer S. Emetic toxin formation of Bacillus cereus is restricted to a single evolutionary lineage of closely related strains. Microbiology (Reading) 2005; 151:183-197. [PMID: 15632437 DOI: 10.1099/mic.0.27607-0] [Citation(s) in RCA: 232] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
An in-depth polyphasic approach was applied to study the population structure of the human pathogen Bacillus cereus. To assess the intraspecific biodiversity of this species, which is the causative agent of gastrointestinal diseases, a total of 90 isolates from diverse geographical origin were studied by genetic [M13-PCR, random amplification of polymorphic DNA (RAPD), multilocus sequence typing (MLST)] and phenetic [Fourier transform Infrared (FTIR), protein profiling, biochemical assays] methods. The strain set included clinical strains, isolates from food remnants connected to outbreaks, as well as isolates from diverse food environments with a well documented strain history. The phenotypic and genotypic analysis of the compiled panel of strains illustrated a considerable diversity among B. cereus connected to diarrhoeal syndrome and other non-emetic food strains, but a very low diversity among emetic isolates. Using all typing methods, cluster analysis revealed a single, distinct cluster of emetic B. cereus strains. The isolates belonging to this cluster were neither able to degrade starch nor could they ferment salicin; they did not possess the genes encoding haemolysin BL (Hbl) and showed only weak or no haemolysis. In contrast, haemolytic-enterotoxin-producing B. cereus strains showed a high degree of heterogeneity and were scattered over different clusters when different typing methods were applied. These data provide evidence for a clonal population structure of cereulide-producing emetic B. cereus and indicate that emetic strains represent a highly clonal complex within a potentially panmictic or weakly clonal background population structure of the species. It may have originated only recently through acquisition of specific virulence factors such as the cereulide synthetase gene.
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Affiliation(s)
- Monika Ehling-Schulz
- Lehrstuhl für Mikrobielle Ökologie, Department für Grundlagen der Biowissenschaften, Technische Universität München, Weihenstephaner Berg 3, D-85354 Freising, Germany
| | | | - Marie-Helene Guinebretiere
- Institut National de la Recherche Agronomique, UMR A408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, Domaine Saint-Paul, Site Agroparc, F-84914 Avignon Cedex 9, France
| | - Toril Lindbäck
- Department of Pharmacology, Microbiology and Food Hygiene, The Norwegian School of Veterinary Science, Ullevalsveien 72, PO Box 8146, Dep., N-0033 Oslo, Norway
| | - Maria Andersson
- Dept for Applied Chemistry and Microbiology, College of Agriculture and Forestry at the University of Helsinki, Biocenter PO Box 56, Viikinkaari 9, FIN 00014 Helsinki University, Finland
| | - Anja Schulz
- Institute of Hygiene and Technology of Food of Animal Origin, Ludwig-Maximilians-Universität München, Veterinaerstr 13, D-80539 Munich, Germany
| | - Martina Fricker
- Lehrstuhl für Mikrobielle Ökologie, Department für Grundlagen der Biowissenschaften, Technische Universität München, Weihenstephaner Berg 3, D-85354 Freising, Germany
| | | | - Per Einar Granum
- Department of Pharmacology, Microbiology and Food Hygiene, The Norwegian School of Veterinary Science, Ullevalsveien 72, PO Box 8146, Dep., N-0033 Oslo, Norway
| | - Erwin Märtlbauer
- Institute of Hygiene and Technology of Food of Animal Origin, Ludwig-Maximilians-Universität München, Veterinaerstr 13, D-80539 Munich, Germany
| | - Christophe Nguyen-The
- Institut National de la Recherche Agronomique, UMR A408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, Domaine Saint-Paul, Site Agroparc, F-84914 Avignon Cedex 9, France
| | - Mirja Salkinoja-Salonen
- Dept for Applied Chemistry and Microbiology, College of Agriculture and Forestry at the University of Helsinki, Biocenter PO Box 56, Viikinkaari 9, FIN 00014 Helsinki University, Finland
| | - Siegfried Scherer
- Lehrstuhl für Mikrobielle Ökologie, Department für Grundlagen der Biowissenschaften, Technische Universität München, Weihenstephaner Berg 3, D-85354 Freising, Germany
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Toh M, Moffitt MC, Henrichsen L, Raftery M, Barrow K, Cox JM, Marquis CP, Neilan BA. Cereulide, the emetic toxin of Bacillus cereus, is putatively a product of nonribosomal peptide synthesis. J Appl Microbiol 2004; 97:992-1000. [PMID: 15479414 DOI: 10.1111/j.1365-2672.2004.02381.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To determine if cereulide, the emetic toxin produced by Bacillus cereus, is produced by a nonribosomal peptide synthetase (NRPS). METHODS AND RESULTS NC Y, an emetic strain of Bacillus cereus, was examined for a NRPS gene using PCR with primers recognizing a fragment of a NRPS gene from the cyanobacterium Microcystis. The amplicon was sequenced and compared with other gene sequences using BLAST analysis, which showed that the amplicon from strain NC Y was similar in sequence to peptide synthetase genes in other micro-organisms, including Bacillus subtilis and B. brevis, while no such sequence was found in the complete genome sequence of a nonemetic strain of B. cereus. Specific PCR primers were then designed and used to screen 40 B. cereus isolates previously implicated in outbreaks of foodborne illness. The isolates were also screened for toxin production using the MTT cell cytotoxicity assay. PCR and MTT assay screening of the B. cereus isolates revealed a high correlation between the presence of the NRPS gene and cereulide production. CONCLUSIONS The results indicate that cereulide is produced by a NRPS complex. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first study to provide evidence identifying the mechanism of production of cereulide, the emetic toxin of B. cereus. The PCR primers developed in the study allow determination of the potential for cereulide production among isolates of B. cereus.
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Affiliation(s)
- M Toh
- Food Science and Technology, School of Chemical Engineering and Industrial Chemistry, The University of New South Wales, Sydney, Australia
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Abstract
CASE HISTORY A 25-year-old woman who had ingested about 20 tablets of diazepam 2.5 mg in a suicide attempt was given cupric sulfate 2.5 g in 1750 mL water as an emetic, but died 3 days later. On autopsy, death was attributed to acute hemolysis and acute renal failure due to copper poisoning. Copper concentrations were 5.31 microg/mL in whole blood, 19.0 microg/g in the liver, 8.9 microg/g in the kidney, 1.1 microg/L in the brain, 1.1 microg/g in the gastric wall, 1.5 microg/g in the jejunal wall, 0.3 microg/g in the colon wall, 4.6 microg/g in the gastric contents, and 12.6 microg/g in the intestinal contents (fresh weight). This case and 10 others from the Chinese medical literature provide additional evidence that cupric sulfate is a corrosive poison and contraindicated as an emetic.
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Affiliation(s)
- J Liu
- Department of Chemistry, China Medical University, Shenyang, People's Republic of China.
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Asano T, Kushida H, Sadakane C, Ishihara K, Wakui Y, Yanagisawa T, Kimura M, Kamei H, Yoshida T. Metabolism of ipecac alkaloids cephaeline and emetine by human hepatic microsomal cytochrome P450s, and their inhibitory effects on P450 enzyme activities. Biol Pharm Bull 2001; 24:678-82. [PMID: 11411558 DOI: 10.1248/bpb.24.678] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this study, we identified the metabolites and the CYP forms that are specifically involved in emetine O-demethylation in human liver microsomes, and cleared the inhibitory potential of cephaeline and emetine on the activity of the major drug-metabolizing CYP enzymes. Incubation of emetine with human liver microsomes yielded three metabolites identified by using HPLC by comparison of the retention time with the authentic sample of cephaeline, 9-O-demethylemetine and 10-O-demethylemetine. CYP3A4 and CYP2D6 were able to metabolize emetine to cephaeline and 9-O-demethylemetine, and CYP3A4 also participated in metabolizing emetine to 10-O-demethylemetine. Cephaeline and emetine inhibited probe substrates metabolism. IC50 for cephaeline against CYP2D6 and CYP3A4 were 121 and 1000 microM, respectively. For the emetine, CYP2D6 and CYP3A4 were 80 and 480 microM, respectively. Inhibition constants (Ki) for both compounds on the CYP2D6 and CYP3A4 activities were determined by graphic analysis of Dixon plots at various concentrations. The obtained Ki values of cephaeline for CYP2D6 and CYP3A4 were 54 and 355 microM, respectively, and the values of emetine were 43 and 232 microM, respectively. We concluded that these in vitro inhibitions of cephaeline and emetine would hardly increase plasma concentrations of co-administered drugs in clinical therapy.
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Affiliation(s)
- T Asano
- New Drug Discovery Laboratories R&D Division, Tsumura & Co.. Ltd., Inashiki, Ibaraki, Japan.
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Abstract
Seven emetic toxin-producing strains of Bacillus cereus were examined for toxin production in Skim Milk Medium at incubation temperatures ranging from 10 to 50 degrees C. Minimum and maximum growth temperatures were found to be 12 and 46 degrees C, respectively. At 12 and 15 degrees C, levels of toxin production were significantly higher (P < 0.01) than that observed at 30 degrees C, while no toxin was produced above 37 degrees C. Increased levels of sporulation were observed at increased temperatures, and no correlation was found between levels of sporulation and toxin production (R(2) = 0.086).
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Affiliation(s)
- W J Finlay
- School of Biological and Biomedical Sciences, Glasgow Caledonian University, UK
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12
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Decker WJ, Goldsmith WA, Mills RC, Banez RJ. Systemic absorption of copper after oral administration of radioactive copper sulfate emetic in rats. Toxicol Appl Pharmacol 1972; 21:331-4. [PMID: 5027966 DOI: 10.1016/0041-008x(72)90152-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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