1
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Herman RA, Zhang JXQ. Simulated gastric fluid assay for estimating the digestibility of newly expressed proteins in GE crops: Missteps in development and interpretation. Food Chem Toxicol 2022; 169:113436. [PMID: 36165819 DOI: 10.1016/j.fct.2022.113436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/09/2022] [Accepted: 09/14/2022] [Indexed: 11/28/2022]
Abstract
Digestive stability of a food protein in simulated gastric fluid (SGF) continues to be considered a risk factor for allergy, even though the current science does not support this belief. Methodological shortcomings of the adaption of the SGF assay for use with purified proteins has been cited as a reason to discount results that do not conform to this belief. Missteps in conducting and interpreting the results of SGF assays are reviewed here. However, these methodological shortcomings do not invalidate the conclusion that allergenic proteins are not systematically more stable to digestion than non-allergens. The growing evidence for the dual allergen exposure hypothesis, whereby sensitization to food allergens is primarily caused by dermal and inhalation exposure to food dust, and tolerization against food allergy is primarily induced by gut exposure in food, likely explains why the digestive stability of a protein is not a risk factor for allergenicity.
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Affiliation(s)
- Rod A Herman
- Corteva Agriscience, Regulatory and Stewardship, Indianapolis, IN, 46268, USA.
| | - John X Q Zhang
- Corteva Agriscience, Regulatory and Stewardship, Johnston, IA, USA
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2
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Park EJ, Han JS, Park EJ, Seong E, Lee GH, Kim DW, Son HY, Han HY, Lee BS. Repeated-oral dose toxicity of polyethylene microplastics and the possible implications on reproduction and development of the next generation. Toxicol Lett 2020; 324:75-85. [PMID: 31954868 DOI: 10.1016/j.toxlet.2020.01.008] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 11/26/2019] [Accepted: 01/12/2020] [Indexed: 12/21/2022]
Abstract
With the increased distribution of microplastics in the environment, the potential for harmful effects on human health and ecosystems have become a global concern. Considering that polyethylene microplastics (PE-MPs) are among the most produced plastics worldwide, we administered PE-MPs (0.125, 0.5, 2 mg/day/mouse) by gavage to mice (10 mice/sex/dose) for 90 days. Compared to control, the body weight gain was significantly reduced in the male mice, and the proportion of neutrophils in the blood stream clearly increased in both sexes of mice. Persistence of a PE-MPs-like material and migration of granules to the mast cell membrane and accumulation of damaged organelles were observed in the stomachs and the spleens from the treated dams, respectively. Additionally, the IgA level in the blood stream was significantly elevated in the dams administered with PE-MPs compared to control, and the subpopulation of lymphocytes within the spleen was altered. Following, we performed an additional study to screen the effects of PE-MPs on reproduction and development (5 mice/sex/dose). Importantly, number of live births per dam, the sex ratio of pups, and body weight of pups was notably altered in groups treated with PE-MPs compared to the control group. Additionally, PE-MPs affected the subpopulation of lymphocytes within the spleen of the offspring, as did in the dams. Therefore, we propose that reproductive and developmental toxicity testing is warranted to evaluate the safety of microplastics. Additionally, we suggest that the IgA level may be used as a biomarker for harmful effects following exposure on microplastics.
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Affiliation(s)
- Eun-Jung Park
- Graduate School of East-West Medical Science, Kyung Hee University, Yongin, 17104, Republic of Korea; Bionanocomposite Research Center, Kyung Hee University, Seoul, 02447, Republic of Korea.
| | - Ji-Seok Han
- Toxicopathological Center, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea; Department of Veterinary Pathology, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Eun-Jun Park
- Graduate School of East-West Medical Science, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Eunsol Seong
- Graduate School of East-West Medical Science, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Gwang-Hee Lee
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Dong-Wan Kim
- School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Hwa-Young Son
- Department of Veterinary Pathology, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
| | - Hyoung-Yun Han
- Department of Predictive Toxicology Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea
| | - Byoung-Seok Lee
- Toxicopathological Center, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea
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Colgrave ML, Byrne K, Caine J, Kowalczyk L, Vibhakaran Pillai S, Dong B, Lovrecz G, MacIntosh S, Scoble JA, Petrie JR, Singh S, Zhou XR. Proteomics reveals the in vitro protein digestibility of seven transmembrane enzymes from the docosahexaenoic acid biosynthesis pathway. Food Chem Toxicol 2019; 130:89-98. [PMID: 31085220 DOI: 10.1016/j.fct.2019.05.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 05/08/2019] [Accepted: 05/10/2019] [Indexed: 11/29/2022]
Abstract
The measurement of protein digestibility is one of the key steps in determining the safety of a genetically modified crop that has been traditionally accomplished using antibodies. Membrane proteins are often extremely difficult to express with replicated authentic tertiary structure in heterologous systems. As a result raising antibodies for use in safety assessment may not be feasible. In this study, LC-MS based proteomics was used to characterise seven transmembrane enzymes from the docosahexaenoic acid biosynthetic pathway that had been introduced into canola. The application of a two-stage digestion strategy involving simulated gastric fluid followed by trypsin enabled the measurement of protein digestibility in vitro. Tryptic peptide markers that spanned the length of each desaturase protein were monitored and showed that these proteins were readily degraded (>95% within 5 min) and highlighted regions of the elongase enzymes that showed limited resistance to simulated gastric digestion. Traditional gel-based and Western blotting analysis of ω3-desaturase and Δ6-elongase revealed rapid hydrolysis of the intact proteins within seconds and no fragments (>3 kDa) remained after 60 min, complementing the novel approach described herein. The LC-MS approach was sensitive, selective and did not require the use of purified proteins.
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Affiliation(s)
| | - Keren Byrne
- CSIRO Agriculture and Food, 306 Carmody Rd, St Lucia, QLD, 4067, Australia
| | - Joanne Caine
- CSIRO Manufacturing, 343 Royal Parade, Parkville, VIC, 3052, Australia
| | - Lukasz Kowalczyk
- CSIRO Manufacturing, 343 Royal Parade, Parkville, VIC, 3052, Australia
| | | | - Bei Dong
- CSIRO Agriculture and Food, GPO Box 1700, Canberra, ACT, 2601, Australia
| | - George Lovrecz
- CSIRO Manufacturing, 343 Royal Parade, Parkville, VIC, 3052, Australia
| | - Susan MacIntosh
- Nuseed Americas, 11901 S. Austin Avenue, Alsip, IL, 60803, USA
| | - Judith A Scoble
- CSIRO Manufacturing, 343 Royal Parade, Parkville, VIC, 3052, Australia
| | - James R Petrie
- CSIRO Agriculture and Food, GPO Box 1700, Canberra, ACT, 2601, Australia
| | - Surinder Singh
- CSIRO Agriculture and Food, GPO Box 1700, Canberra, ACT, 2601, Australia
| | - Xue-Rong Zhou
- CSIRO Agriculture and Food, GPO Box 1700, Canberra, ACT, 2601, Australia
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4
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Song P, Podevin N, Mirsky H, Anderson J, Delaney B, Mathesius C, Rowe L, Herman RA. Q-X1-P-X2 motif search for potential celiac disease risk has poor selectivity. Regul Toxicol Pharmacol 2018; 99:233-237. [PMID: 30266240 DOI: 10.1016/j.yrtph.2018.09.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/19/2018] [Accepted: 09/21/2018] [Indexed: 11/24/2022]
Abstract
The European Food Safety Authority (EFSA) recently published guidelines for assessment of potential celiac disease risk for newly expressed proteins in genetically modified (GM) crops. This novel step-wise approach prescribes, in part, how to conduct sequence identity searches between a newly expressed protein and known celiac disease peptides including a Q/E-X1-P-X2 amino acid motif. To evaluate the specificity of the recommended sequence identity searches in the context of risk assessment, protein sequences from celiac disease causing crops, as well as from crops not associated with celiac disease, were compared with known HLA-DQ restricted epitopes and searched for the presence of motifs followed by peptide analysis. Searches for the presence of the Q/E-X1-P-X2-motif were found to generate a high proportion of false-positive hits irrelevant to celiac disease risk. Identification of a 9mer exact match between a newly expressed protein and the known celiac disease peptides (recommended by the guideline) along with a supplementary sequence comparisons (suggested by FARRP/AllergenOnline) is considered better suited to more specifically capture the potential risk of a newly expressed protein for celiac disease.
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Affiliation(s)
- Ping Song
- Corteva Agriscience™, Agriculture Division of DowDuPont™, Indianapolis, IN, USA.
| | - Nancy Podevin
- Corteva Agriscience™, Agriculture Division of DowDuPont™, Johnston, IA, USA
| | - Henry Mirsky
- Corteva Agriscience™, Agriculture Division of DowDuPont™, Johnston, IA, USA
| | - Jennifer Anderson
- Corteva Agriscience™, Agriculture Division of DowDuPont™, Johnston, IA, USA
| | - Bryan Delaney
- Corteva Agriscience™, Agriculture Division of DowDuPont™, Johnston, IA, USA
| | - Carey Mathesius
- Corteva Agriscience™, Agriculture Division of DowDuPont™, Johnston, IA, USA
| | - Laura Rowe
- Corteva Agriscience™, Agriculture Division of DowDuPont™, Johnston, IA, USA
| | - Rod A Herman
- Corteva Agriscience™, Agriculture Division of DowDuPont™, Indianapolis, IN, USA
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Herman RA, Ekmay RD, Schafer BW, Song P, Fast BJ, Papineni S, Shan G, Juberg DR. Food and feed safety of DAS-444Ø6-6 herbicide-tolerant soybean. Regul Toxicol Pharmacol 2018; 94:70-74. [PMID: 29366656 DOI: 10.1016/j.yrtph.2018.01.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/17/2017] [Accepted: 01/18/2018] [Indexed: 11/24/2022]
Abstract
DAS-444Ø6-6 soybean was genetically engineered (GE) to withstand applications of three different herbicides. Tolerance to glufosinate and glyphosate is achieved through expression of the phosphinothricin acetyltransferase (PAT) and double-mutated maize 5-enolpyruvyl shikimate-3-phosphate synthase (2mEPSPS) enzymes, respectively. These proteins are expressed in currently commercialized crops and represent no novel risk. Tolerance to 2,4-dichlorophenoxyacetic acid (2,4-D) is achieved through expression of the aryloxyalkanoate dioxygenase 12 (AAD-12) enzyme, which is novel in crops. The safety of the AAD-12 protein and DAS-444Ø6-6 event was assessed for food and feed safety based on the weight of evidence and found to be as safe as non-GE soybean.
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Affiliation(s)
- Rod A Herman
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA.
| | - Ricardo D Ekmay
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Barry W Schafer
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Ping Song
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Brandon J Fast
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Sabitha Papineni
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Guomin Shan
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Daland R Juberg
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
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6
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Papineni S, Thomas J, Marshall VA, Juberg DR, Herman RA. No treatment-related effects with aryloxyalkanoate dioxygenase-12 in three 28-day mouse toxicity studies. Regul Toxicol Pharmacol 2018; 92:220-225. [PMID: 29258926 DOI: 10.1016/j.yrtph.2017.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 12/13/2017] [Accepted: 12/15/2017] [Indexed: 11/28/2022]
Abstract
The aryloxyalkanoate dioxygenase-12 (AAD-12) protein is expressed in genetically modified soybean events DAS-68416-4 and DAS-444Ø6-6. Expression of the AAD-12 protein in soybeans confers tolerance to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) providing an additional herbicide choice to farmers. This enzyme acts by catalyzing the degradation of 2,4-D into herbicidally inactive metabolites. To meet evolving interpretation of regulations in the European Union, three separate 28-day repeat-dose oral mouse studies were conducted at increasing doses of up to 1100 mg AAD-12 protein/kg bw/day. No treatment-related effects were seen in any of these three studies.
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Affiliation(s)
- Sabitha Papineni
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN 46268, USA.
| | - Johnson Thomas
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, 1803 Building, Washington Street, Midland, MI 48674, USA.
| | - Valerie A Marshall
- Toxicology and Environmental Research and Consulting, The Dow Chemical Company, 1803 Building, Washington Street, Midland, MI 48674, USA.
| | - Daland R Juberg
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN 46268, USA.
| | - Rod A Herman
- Dow AgroSciences LLC., 9330 Zionsville Road, Indianapolis, IN 46268, USA.
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