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Kara HH, Araiza-Calahorra A, Rigby NM, Sarkar A. Flaxseed oleosomes: Responsiveness to physicochemical stresses, tribological shear and storage. Food Chem 2024; 431:137160. [PMID: 37604004 DOI: 10.1016/j.foodchem.2023.137160] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [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: 06/16/2023] [Revised: 08/04/2023] [Accepted: 08/13/2023] [Indexed: 08/23/2023]
Abstract
This study aimed to extract oleosomes (OLs) from flaxseeds and assess their response to environmental conditions during storage (pH and ionic strengths), shear and tribological stresses. Our hypothesis was that a shear-induced instability will enable OLs to exhibit favourable lubrication performance. During storage, OLs exhibited resistance to droplet aggregation for up to 6 weeks owing to the proteins (3.5-152.8 kDa molecular weights) stabilizing the OL droplets. However, presence of divalent (Ca2+) ions induced destabilization with marked increase in droplet size (p < 0.05). OLs demonstrated shear thinning behaviour, displaying an order of magnitude higher viscosity than flaxseed oil (FSO) at low shear rates (<10 s-1). Strikingly, OLs mirrored the frictional profile of FSO regardless of entrainment speeds, due to droplet coalescence, validating the hypothesis. Such kinetic stability with shear-induced coalescing feature of OLs hold strong potential for future plant-based food development, particularly in achieving desired mouthfeel characteristics.
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Affiliation(s)
- Hasan H Kara
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK; Nutrition and Dietetics Department, Faculty of Health Sciences, Necmettin Erbakan University, 42090 Meram, Konya, Turkiye
| | - Andrea Araiza-Calahorra
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK
| | - Neil M Rigby
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK
| | - Anwesha Sarkar
- Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK.
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2
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Krupa Ł, Staroń R, Dulko D, Łozińska N, Mackie AR, Rigby NM, Macierzanka A, Markiewicz A, Jungnickel C. Importance of Bile Composition for Diagnosis of Biliary Obstructions. Molecules 2021; 26:7279. [PMID: 34885858 PMCID: PMC8659177 DOI: 10.3390/molecules26237279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 11/26/2021] [Accepted: 11/27/2021] [Indexed: 01/01/2023] Open
Abstract
Determination of the cause of a biliary obstruction is often inconclusive from serum analysis alone without further clinical tests. To this end, serum markers as well as the composition of bile of 74 patients with biliary obstructions were determined to improve the diagnoses. The samples were collected from the patients during an endoscopic retrograde cholangiopancreatography (ERCP). The concentration of eight bile salts, specifically sodium cholate, sodium glycocholate, sodium taurocholate, sodium glycodeoxycholate, sodium chenodeoxycholate, sodium glycochenodeoxycholate, sodium taurodeoxycholate, and sodium taurochenodeoxycholate as well as bile cholesterol were determined by HPLC-MS. Serum alanine aminotransferase (ALT), aspartate transaminase (AST), and bilirubin were measured before the ERCP. The aim was to determine a diagnostic factor and gain insights into the influence of serum bilirubin as well as bile salts on diseases. Ratios of conjugated/unconjugated, primary/secondary, and taurine/glycine conjugated bile salts were determined to facilitate the comparison to literature data. Receiver operating characteristic (ROC) curves were determined, and the cut-off values were calculated by determining the point closest to (0,1). It was found that serum bilirubin was a good indicator of the type of biliary obstruction; it was able to differentiate between benign obstructions such as choledocholithiasis (at the concentration of >11 µmol/L) and malignant changes such as pancreatic neoplasms or cholangiocarcinoma (at the concentration of >59 µmol/L). In addition, it was shown that conjugated/unconjugated bile salts confirm the presence of an obstruction. With lower levels of conjugated/unconjugated bile salts the possibility for inflammation and, thus, neoplasms increase.
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Affiliation(s)
- Łukasz Krupa
- Teaching Hospital No 1, Department of Gastroenterology and Hepatology with Internal Disease Unit, Chopina 2, 35-055 Rzeszów, Poland; (Ł.K.); (R.S.)
- Medical Department, University of Rzeszów, Kopisto 2a, 35-310 Rzeszów, Poland
| | - Robert Staroń
- Teaching Hospital No 1, Department of Gastroenterology and Hepatology with Internal Disease Unit, Chopina 2, 35-055 Rzeszów, Poland; (Ł.K.); (R.S.)
- Medical Department, University of Rzeszów, Kopisto 2a, 35-310 Rzeszów, Poland
| | - Dorota Dulko
- Department of Colloid and Lipid Science, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland; (D.D.); (N.Ł.); (A.M.)
| | - Natalia Łozińska
- Department of Colloid and Lipid Science, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland; (D.D.); (N.Ł.); (A.M.)
| | - Alan R. Mackie
- School of Food Science & Nutrition, University of Leeds, Leeds LS2 9JT, UK; (A.R.M.); (N.M.R.)
| | - Neil M. Rigby
- School of Food Science & Nutrition, University of Leeds, Leeds LS2 9JT, UK; (A.R.M.); (N.M.R.)
| | - Adam Macierzanka
- Department of Colloid and Lipid Science, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland; (D.D.); (N.Ł.); (A.M.)
| | - Aleksandra Markiewicz
- Laboratory of Translational Oncology Intercollegiate, Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, 80-211 Gdańsk, Poland;
| | - Christian Jungnickel
- Department of Colloid and Lipid Science, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland; (D.D.); (N.Ł.); (A.M.)
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Dulko D, Staroń R, Krupa L, Rigby NM, Mackie AR, Gutkowski K, Wasik A, Macierzanka A. The bile salt content of human bile impacts on simulated intestinal proteolysis of β-lactoglobulin. Food Res Int 2021; 145:110413. [PMID: 34112416 DOI: 10.1016/j.foodres.2021.110413] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 03/27/2021] [Accepted: 05/08/2021] [Indexed: 12/12/2022]
Abstract
The gastrointestinal hydrolysis of food proteins has been portrayed in scientific literature to predominantly depend on the activity and specificity of proteolytic enzymes. Human bile has not been considered to facilitate proteolysis in the small intestine, but rather to assist in intestinal lipolysis. However, human bile can potentially influence proteins that are largely resistant to gastric digestion, and which are mainly hydrolysed after they have been transferred to the small intestine. We used purified and food-grade bovine milk β-lactoglobulin (βLg) to assess the impact of bile salts (BS) on the in vitro gastrointestinal digestion of this protein. Quantitative analysis showed that the proteolysis rate increased significantly with increasing BS concentration. The effect was consistent regardless of whether individual BS or real human bile samples, varying in BS concentrations, were used. The total BS content of bile was more important than its BS composition in facilitating the proteolysis of βlg. We also show that the impact of human bile observed during the digestion of purified βLg and βLg-rich whey protein isolate can be closely replicated by the use of individual BS mixed with phosphatidylcholine. This could validate simple BS/phosphatidylcholine mixtures as human-relevant substitutes of difficult-to-obtain human bile for in vitro proteolysis studies.
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Affiliation(s)
- Dorota Dulko
- Gdańsk University of Technology, Faculty of Chemistry, Department of Colloid and Lipid Science, Gabriela Narutowicza 11/12, 80-322 Gdańsk, Poland
| | - Robert Staroń
- Department of Gastroenterology and Hepatology with Internal Disease Unit, Teaching Hospital No 1, Chopina 2, 35-055 Rzeszów, Poland
| | - Lukasz Krupa
- Department of Gastroenterology and Hepatology with Internal Disease Unit, Teaching Hospital No 1, Chopina 2, 35-055 Rzeszów, Poland
| | - Neil M Rigby
- University of Leeds, School of Food Science and Nutrition, Leeds LS2 9JT, United Kingdom
| | - Alan R Mackie
- University of Leeds, School of Food Science and Nutrition, Leeds LS2 9JT, United Kingdom
| | - Krzysztof Gutkowski
- Department of Gastroenterology and Hepatology with Internal Disease Unit, Teaching Hospital No 1, Chopina 2, 35-055 Rzeszów, Poland
| | - Andrzej Wasik
- Gdańsk University of Technology, Faculty of Chemistry, Department of Analytical Chemistry, Gabriela Narutowicza 11/12, 80-322 Gdańsk, Poland
| | - Adam Macierzanka
- Gdańsk University of Technology, Faculty of Chemistry, Department of Colloid and Lipid Science, Gabriela Narutowicza 11/12, 80-322 Gdańsk, Poland.
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Mackie AR, Bajka BH, Rigby NM, Wilde PJ, Alves-Pereira F, Mosleth EF, Rieder A, Kirkhus B, Salt LJ. Oatmeal particle size alters glycemic index but not as a function of gastric emptying rate. Am J Physiol Gastrointest Liver Physiol 2017; 313:G239-G246. [PMID: 28572083 DOI: 10.1152/ajpgi.00005.2017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 05/09/2017] [Accepted: 05/24/2017] [Indexed: 01/31/2023]
Abstract
The aim of this study was to determine the extent to which oat particle size in a porridge could alter glucose absorption, gastric emptying, gastrointestinal hormone response, and subjective feelings of appetite and satiety. Porridge was prepared from either oat flakes or oat flour with the same protein, fat, carbohydrate, and mass. These were fed to eight volunteers on separate days in a crossover study, and subjective appetite ratings, gastric contents, and plasma glucose, insulin, and gastrointestinal hormones were determined over a period of 3 h. The flake porridge gave a lower glucose response than the flour porridge, and there were apparent differences in gastric emptying in both the early and late postprandial phases. The appetite ratings showed similar differences between early- and late-phase behavior. The structure of the oat flakes remained sufficiently intact to delay their gastric emptying, leading to a lower glycemic response, even though initial gastric emptying rates were similar for the flake and flour porridge. This highlights the need to take food structure into account when considering relatively simple physiological measures and offering nutritional guidance.NEW & NOTEWORTHY The impact of food structure on glycemic response even in simple foods such as porridge is dependent on both timing of gastric emptying and the composition of what is emptied as well as duodenal starch digestion. Thus structure should be accounted for when considering relatively simple physiological measures and offering nutritional guidance.
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Affiliation(s)
- Alan R Mackie
- Institute of Food Research, Norwich Research Park, Norwich, United Kingdom; .,School of Food Science and Nutrition, University of Leeds, Leeds, United Kingdom
| | - Balazs H Bajka
- Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
| | - Neil M Rigby
- Institute of Food Research, Norwich Research Park, Norwich, United Kingdom.,School of Food Science and Nutrition, University of Leeds, Leeds, United Kingdom
| | - Peter J Wilde
- Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
| | - Fatima Alves-Pereira
- Radiology Department, Norfolk and Norwich University Hospital, Norwich, United Kingdom; and
| | | | | | | | - Louise J Salt
- Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
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6
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Mulet-Cabero AI, Rigby NM, Brodkorb A, Mackie AR. Dairy food structures influence the rates of nutrient digestion through different in vitro gastric behaviour. Food Hydrocoll 2017. [DOI: 10.1016/j.foodhyd.2016.12.039] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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7
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Gunning Y, Watson AD, Rigby NM, Philo M, Peazer JK, Kemsley EK. Species Determination and Quantitation in Mixtures Using MRM Mass Spectrometry of Peptides Applied to Meat Authentication. J Vis Exp 2016. [PMID: 27685654 PMCID: PMC5092036 DOI: 10.3791/54420] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We describe a simple protocol for identifying and quantifying the two components in binary mixtures of species possessing one or more similar proteins. Central to the method is the identification of 'corresponding proteins' in the species of interest, in other words proteins that are nominally the same but possess species-specific sequence differences. When subject to proteolysis, corresponding proteins will give rise to some peptides which are likewise similar but with species-specific variants. These are 'corresponding peptides'. Species-specific peptides can be used as markers for species determination, while pairs of corresponding peptides permit relative quantitation of two species in a mixture. The peptides are detected using multiple reaction monitoring (MRM) mass spectrometry, a highly specific technique that enables peptide-based species determination even in complex systems. In addition, the ratio of MRM peak areas deriving from corresponding peptides supports relative quantitation. Since corresponding proteins and peptides will, in the main, behave similarly in both processing and in experimental extraction and sample preparation, the relative quantitation should remain comparatively robust. In addition, this approach does not need the standards and calibrations required by absolute quantitation methods. The protocol is described in the context of red meats, which have convenient corresponding proteins in the form of their respective myoglobins. This application is relevant to food fraud detection: the method can detect 1% weight for weight of horse meat in beef. The corresponding protein, corresponding peptide (CPCP) relative quantitation using MRM peak area ratios gives good estimates of the weight for weight composition of a horse plus beef mixture.
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Affiliation(s)
| | | | | | - Mark Philo
- Analytical Sciences Unit, Institute of Food Research
| | - Joshua K Peazer
- Analytical Sciences Unit, Institute of Food Research; School of Chemistry, University of East Anglia
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8
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Abdullah SU, Alexeev Y, Johnson PE, Rigby NM, Mackie AR, Dhaliwal B, Mills ENC. Ligand binding to an Allergenic Lipid Transfer Protein Enhances Conformational Flexibility resulting in an Increase in Susceptibility to Gastroduodenal Proteolysis. Sci Rep 2016; 6:30279. [PMID: 27458082 PMCID: PMC4960534 DOI: 10.1038/srep30279] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/29/2016] [Indexed: 11/29/2022] Open
Abstract
Non-specific lipid transfer proteins (LTPs) are a family of lipid-binding molecules that are widely distributed across flowering plant species, many of which have been identified as allergens. They are highly resistant to simulated gastroduodenal proteolysis, a property that may play a role in determining their allergenicity and it has been suggested that lipid binding may further increase stability to proteolysis. It is demonstrated that LTPs from wheat and peach bind a range of lipids in a variety of conditions, including those found in the gastroduodenal tract. Both LTPs are initially cleaved during gastroduodenal proteolysis at three major sites between residues 39–40, 56–57 and 79–80, with wheat LTP being more resistant to cleavage than its peach ortholog. The susceptibility of wheat LTP to proteolyic cleavage increases significantly upon lipid binding. This enhanced digestibility is likely to be due to the displacement of Tyr79 and surrounding residues from the internal hydrophobic cavity upon ligand binding to the solvent exposed exterior of the LTP, facilitating proteolysis. Such knowledge contributes to our understanding as to how resistance to digestion can be used in allergenicity risk assessment of novel food proteins, including GMOs.
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Affiliation(s)
| | - Yuri Alexeev
- Institute of Food Research, Norwich Research Park, Colney, NR4 7UA, UK
| | - Philip E Johnson
- Institute of Food Research, Norwich Research Park, Colney, NR4 7UA, UK.,Institute of Inflammation and Repair, Manchester Academic Health Sciences Centre and Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Neil M Rigby
- Institute of Food Research, Norwich Research Park, Colney, NR4 7UA, UK
| | - Alan R Mackie
- Institute of Food Research, Norwich Research Park, Colney, NR4 7UA, UK
| | - Balvinder Dhaliwal
- Institute of Inflammation and Repair, Manchester Academic Health Sciences Centre and Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - E N Clare Mills
- Institute of Food Research, Norwich Research Park, Colney, NR4 7UA, UK.,Institute of Inflammation and Repair, Manchester Academic Health Sciences Centre and Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
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9
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Watson AD, Gunning Y, Rigby NM, Philo M, Kemsley EK. Meat Authentication via Multiple Reaction Monitoring Mass Spectrometry of Myoglobin Peptides. Anal Chem 2015; 87:10315-22. [DOI: 10.1021/acs.analchem.5b02318] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Andrew D. Watson
- Analytical Sciences Unit, Institute of Food Research, Norwich
Research Park, Norwich NR4 7UA, United Kingdom
| | - Yvonne Gunning
- Analytical Sciences Unit, Institute of Food Research, Norwich
Research Park, Norwich NR4 7UA, United Kingdom
| | - Neil M. Rigby
- Analytical Sciences Unit, Institute of Food Research, Norwich
Research Park, Norwich NR4 7UA, United Kingdom
| | - Mark Philo
- Analytical Sciences Unit, Institute of Food Research, Norwich
Research Park, Norwich NR4 7UA, United Kingdom
| | - E. Kate Kemsley
- Analytical Sciences Unit, Institute of Food Research, Norwich
Research Park, Norwich NR4 7UA, United Kingdom
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10
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Christiansen A, Kringelum JV, Hansen CS, Bøgh KL, Sullivan E, Patel J, Rigby NM, Eiwegger T, Szépfalusi Z, de Masi F, Nielsen M, Lund O, Dufva M. High-throughput sequencing enhanced phage display enables the identification of patient-specific epitope motifs in serum. Sci Rep 2015; 5:12913. [PMID: 26246327 PMCID: PMC4650709 DOI: 10.1038/srep12913] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 07/08/2015] [Indexed: 12/13/2022] Open
Abstract
Phage display is a prominent screening technique with a multitude of applications including therapeutic antibody development and mapping of antigen epitopes. In this study, phages were selected based on their interaction with patient serum and exhaustively characterised by high-throughput sequencing. A bioinformatics approach was developed in order to identify peptide motifs of interest based on clustering and contrasting to control samples. Comparison of patient and control samples confirmed a major issue in phage display, namely the selection of unspecific peptides. The potential of the bioinformatic approach was demonstrated by identifying epitopes of a prominent peanut allergen, Ara h 1, in sera from patients with severe peanut allergy. The identified epitopes were confirmed by high-density peptide micro-arrays. The present study demonstrates that high-throughput sequencing can empower phage display by (i) enabling the analysis of complex biological samples, (ii) circumventing the traditional laborious picking and functional testing of individual phage clones and (iii) reducing the number of selection rounds.
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Affiliation(s)
- Anders Christiansen
- Department of Micro- and Nanotechnology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Jens V Kringelum
- Center for Biological Sequence Analysis, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Christian S Hansen
- Center for Biological Sequence Analysis, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Katrine L Bøgh
- National Food Institute, Technical University of Denmark, Søborg, Denmark
| | - Eric Sullivan
- Roche NimbleGen, Madison, Wisconsin, the United States of America
| | - Jigar Patel
- Roche NimbleGen, Madison, Wisconsin, the United States of America
| | - Neil M Rigby
- Institute of Food Research, Norwich, United Kingdom
| | - Thomas Eiwegger
- Department of Paediatrics, Medical University of Vienna, Vienna, Austria
| | - Zsolt Szépfalusi
- Department of Paediatrics, Medical University of Vienna, Vienna, Austria
| | - Federico de Masi
- Center for Biological Sequence Analysis, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Morten Nielsen
- 1] Center for Biological Sequence Analysis, Technical University of Denmark, Kgs. Lyngby, Denmark [2] Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Ole Lund
- Center for Biological Sequence Analysis, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Martin Dufva
- Department of Micro- and Nanotechnology, Technical University of Denmark, Kgs. Lyngby, Denmark
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Bajka BH, Rigby NM, Cross KL, Macierzanka A, Mackie AR. The influence of small intestinal mucus structure on particle transport ex vivo. Colloids Surf B Biointerfaces 2015; 135:73-80. [PMID: 26241918 DOI: 10.1016/j.colsurfb.2015.07.038] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 07/14/2015] [Accepted: 07/15/2015] [Indexed: 12/17/2022]
Abstract
Mucus provides a barrier to bacteria and toxins while allowing nutrient absorption and waste transport. Unlike colonic mucus, small intestinal mucus structure is poorly understood. This study aimed to provide evidence for a continuous, structured mucus layer and assess the diffusion of different sized particles through it. Mucus structure was assessed by histology and immunohistochemistry. Ultra-structure was assessed by scanning electron microscopy. Tracking of 100 nm and 500 nm latex beads was conducted using ex vivo porcine mucus. The porcine jejunum and ileum were filled with mucus. Layered MUC2 staining was visible throughout the small intestine, covering villus tips. Scanning electron microscopy showed net-like mucin sheets covering villi (211 ± 7 nm pore diameter). Particle tracking of 100 nm latex beads, showed no inhibition of diffusion through mucus while 500 nm beads displayed limited diffusion. These results suggest a continuous mucus layer exists throughout the small intestine, which is highly stratified adjacent to the epithelium. The network observed is consistent with previous observations and correlates with stratified MUC2 staining. Mucin pore size is consistent with free diffusion of 100 nm and limited diffusion of 500 nm particles. Small Intestinal mucus structure has important implications for drug delivery systems and prevention and treatment of conditions like mucositis and inflammatory bowel disease.
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Affiliation(s)
| | - Neil M Rigby
- Institute of Food Research, Norwich, Norfolk, UK
| | | | - Adam Macierzanka
- Institute of Food Research, Norwich, Norfolk, UK; Department of Fats and Detergents Technology, Faculty of Chemistry, Gdansk University of Technology, Narutowicza 11/12, 80-952 Gdansk, Poland
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12
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Downs ML, Semic-Jusufagic A, Simpson A, Bartra J, Fernandez-Rivas M, Rigby NM, Taylor SL, Baumert JL, Mills ENC. Characterization of low molecular weight allergens from English walnut (Juglans regia). J Agric Food Chem 2014; 62:11767-75. [PMID: 25388987 DOI: 10.1021/jf504672m] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Although English walnut is a commonly allergenic tree nut, walnut allergens have been poorly characterized to date. The objective of this work was to characterize the natural, low molecular weight (LMW) allergens from walnut. A protocol was developed to purify LMW allergens (specifically 2S albumins) from English walnuts. In addition to 2S albumins, a series of peptides from the N-terminal region of the 7S seed storage globulin proprotein were also identified and characterized. These peptides comprised a four-cysteine motif (C-X-X-X-C-X10-12-C-X-X-X-C) repeated throughout the 7S N-terminal region. Upon IgE immunoblotting, 3/11 and 5/11 sera from walnut-allergic subjects showed IgE reactivity to the 7S N-terminal fragments and 2S albumin, respectively. The mature 7S protein and the newly described 7S N-terminal peptides represent two distinct types of allergens. Because the proteolytic processing of 7S globulins has not been elucidated in many edible plant species, similar protein fragments may be present in other nuts and seeds.
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Affiliation(s)
- Melanie L Downs
- 143 Food Industry Complex, Food Allergy Research and Resource Program, Department of Food Science and Technology, University of Nebraska-Lincoln , Lincoln, Nebraska 68583-0919, United States
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Mandalari G, Rigby NM, Bisignano C, Lo Curto RB, Mulholland F, Su M, Venkatachalam M, Robotham JM, Willison LN, Lapsley K, Roux KH, Sathe SK. Effect of food matrix and processing on release of almond protein during simulated digestion. Lebensm Wiss Technol 2014. [DOI: 10.1016/j.lwt.2014.05.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Parker R, Rigby NM, Ridout MJ, Gunning AP, Wilde PJ. The adsorption-desorption behaviour and structure function relationships of bile salts. Soft Matter 2014; 10:6457-6466. [PMID: 25008989 DOI: 10.1039/c4sm01093k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The digestion of dietary components in the human gastrointestinal (GI) tract is a complex, dynamic, inherently heterogeneous process. A key aspect of the digestion of lipid in the GI tract is the combined action of bile salts, lipase and colipase in hydrolysing and solubilising dispersed lipid. The bile salts are a mixture of steroid acid conjugates with surfactant properties. In order to examine whether the different bile salts have different interfacial properties their dynamic interfacial behaviour was characterised. Differences in the adsorption behaviour to solid hydrophobic surfaces of bile salt species were studied using dual polarisation interferometry and atomic force microscopy (AFM) under physiological conditions. Specifically, the cholates adsorbed more slowly and a significant proportion were irreversibly adsorbed following buffer rinsing; whereas the deoxycholates and chenodeoxycholates adsorbed more rapidly and desorbed to a greater extent following buffer rinsing. The conjugating groups (taurine, glycine) did not influence the behaviour. AFM showed that the interfacial structures that remained following buffer rinsing were also different between these two groups. In addition, the adsorption-desorption behaviour affected the adsorption of colipase to a solid surface. This supports the idea that cooperative adsorption occurs between certain bile salts and colipase to facilitate the adsorption and activity of pancreatic lipase in order to restore lipolytic activity in the presence of bile salts. This study provides insights into how differences in bile salt structure could affect lipase activity and solubilisation of lipolysis products and other lipid-soluble bioactive molecules.
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Affiliation(s)
- Roger Parker
- Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA, UK.
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Kroghsbo S, Rigby NM, Johnson PE, Adel-Patient K, Bøgh KL, Salt LJ, Mills ENC, Madsen CB. Assessment of the sensitizing potential of processed peanut proteins in Brown Norway rats: roasting does not enhance allergenicity. PLoS One 2014; 9:e96475. [PMID: 24805813 PMCID: PMC4013017 DOI: 10.1371/journal.pone.0096475] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 04/08/2014] [Indexed: 11/29/2022] Open
Abstract
Background IgE-binding of process-modified foods or proteins is the most common method for examination of how food processing affects allergenicity of food allergens. How processing affects sensitization capacity is generally studied by administration of purified food proteins or food extracts and not allergens present in their natural food matrix. Objectives The aim was to investigate if thermal processing increases sensitization potential of whole peanuts via the oral route. In parallel, the effect of heating on sensitization potential of the major peanut allergen Ara h 1 was assessed via the intraperitoneal route. Methods Sensitization potential of processed peanut products and Ara h 1 was examined in Brown Norway (BN) rats by oral administration of blanched or oil-roasted peanuts or peanut butter or by intraperitoneal immunization of purified native (N-), heated (H-) or heat glycated (G-)Ara h 1. Levels of specific IgG and IgE were determined by ELISA and IgE functionality was examined by rat basophilic leukemia (RBL) cell assay. Results In rats dosed orally, roasted peanuts induced significant higher levels of specific IgE to NAra h 1 and 2 than blanched peanuts or peanut butter but with the lowest level of RBL degranulation. However, extract from roasted peanuts was found to be a superior elicitor of RBL degranulation. Process-modified Ara h 1 had similar sensitizing capacity as NAra h 1 but specific IgE reacted more readily with process-modified Ara h 1 than with native. Conclusions Peanut products induce functional specific IgE when dosed orally to BN rats. Roasted peanuts do not have a higher sensitizing capacity than blanched peanuts. In spite of this, extract from roasted peanuts is a superior elicitor of RBL cell degranulation irrespectively of the peanut product used for sensitization. The results also suggest that new epitopes are formed or disclosed by heating Ara h 1 without glucose.
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Affiliation(s)
- Stine Kroghsbo
- National Food Institute, Technical University of Denmark, Søborg, Denmark
| | - Neil M. Rigby
- Institute of Food Research, Norwich Research Park, Colney, Norwich, United Kingdom
| | - Philip E. Johnson
- Institute of Food Research, Norwich Research Park, Colney, Norwich, United Kingdom
| | | | - Katrine L. Bøgh
- National Food Institute, Technical University of Denmark, Søborg, Denmark
| | - Louise J. Salt
- Institute of Food Research, Norwich Research Park, Colney, Norwich, United Kingdom
| | - E. N. Clare Mills
- Institute of Food Research, Norwich Research Park, Colney, Norwich, United Kingdom
| | - Charlotte B. Madsen
- National Food Institute, Technical University of Denmark, Søborg, Denmark
- * E-mail:
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16
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Macierzanka A, Mackie AR, Bajka BH, Rigby NM, Nau F, Dupont D. Transport of particles in intestinal mucus under simulated infant and adult physiological conditions: impact of mucus structure and extracellular DNA. PLoS One 2014; 9:e95274. [PMID: 24755941 PMCID: PMC3995753 DOI: 10.1371/journal.pone.0095274] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 03/25/2014] [Indexed: 12/12/2022] Open
Abstract
The final boundary between digested food and the cells that take up nutrients in the small intestine is a protective layer of mucus. In this work, the microstructural organization and permeability of the intestinal mucus have been determined under conditions simulating those of infant and adult human small intestines. As a model, we used the mucus from the proximal (jejunal) small intestines of piglets and adult pigs. Confocal microscopy of both unfixed and fixed mucosal tissue showed mucus lining the entire jejunal epithelium. The mucus contained DNA from shed epithelial cells at different stages of degradation, with higher amounts of DNA found in the adult pig. The pig mucus comprised a coherent network of mucin and DNA with higher viscosity than the more heterogeneous piglet mucus, which resulted in increased permeability of the latter to 500-nm and 1-µm latex beads. Multiple-particle tracking experiments revealed that diffusion of the probe particles was considerably enhanced after treating mucus with DNase. The fraction of diffusive 500-nm probe particles increased in the pig mucus from 0.6% to 64% and in the piglet mucus from ca. 30% to 77% after the treatment. This suggests that extracellular DNA can significantly contribute to the microrheology and barrier properties of the intestinal mucus layer. To our knowledge, this is the first time that the structure and permeability of the small intestinal mucus have been compared between different age groups and the contribution of extracellular DNA highlighted. The results help to define rules governing colloidal transport in the developing small intestine. These are required for engineering orally administered pharmaceutical preparations with improved delivery, as well as for fabricating novel foods with enhanced nutritional quality or for controlled calorie uptake.
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Affiliation(s)
- Adam Macierzanka
- Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
- Agrocampus Ouest, UMR 1253, Rennes, France
- Institut National de la Recherche Agronomique, STLO, UMR 1253, Rennes, France
- * E-mail:
| | - Alan R. Mackie
- Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
| | - Balazs H. Bajka
- Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
| | - Neil M. Rigby
- Institute of Food Research, Norwich Research Park, Norwich, United Kingdom
| | - Françoise Nau
- Agrocampus Ouest, UMR 1253, Rennes, France
- Institut National de la Recherche Agronomique, STLO, UMR 1253, Rennes, France
| | - Didier Dupont
- Agrocampus Ouest, UMR 1253, Rennes, France
- Institut National de la Recherche Agronomique, STLO, UMR 1253, Rennes, France
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17
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Ash A, Burnett GR, Parker R, Ridout MJ, Rigby NM, Wilde PJ. Structural characterisation of parotid and whole mouth salivary pellicles adsorbed onto DPI and QCMD hydroxyapatite sensors. Colloids Surf B Biointerfaces 2014; 116:603-11. [DOI: 10.1016/j.colsurfb.2013.10.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 10/10/2013] [Accepted: 10/16/2013] [Indexed: 10/26/2022]
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18
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Johnson PE, Rigby NM, Dainty JR, Mackie AR, Immer UU, Rogers A, Titchener P, Shoji M, Ryan A, Mata L, Brown H, Holzhauser T, Dumont V, Wykes JA, Walker M, Griffin J, White J, Taylor G, Popping B, Crevel R, Miguel S, Lutter P, Gaskin F, Koerner TB, Clarke D, Sherlock R, Flanagan A, Chan CH, Mills EC. A multi-laboratory evaluation of a clinically-validated incurred quality control material for analysis of allergens in food. Food Chem 2014; 148:30-6. [DOI: 10.1016/j.foodchem.2013.09.115] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 09/17/2013] [Accepted: 09/21/2013] [Indexed: 10/26/2022]
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19
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Macierzanka A, Böttger F, Rigby NM, Lille M, Poutanen K, Mills ENC, Mackie AR. Enzymatically structured emulsions in simulated gastrointestinal environment: impact on interfacial proteolysis and diffusion in intestinal mucus. Langmuir 2012; 28:17349-17362. [PMID: 23171215 DOI: 10.1021/la302194q] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Fundamental knowledge of physicochemical interactions in the gastrointestinal environment is required in order to support rational designing of protein-stabilized colloidal food and pharmaceutical delivery systems with controlled behavior. In this paper, we report on the colloidal behavior of emulsions stabilized with the milk protein sodium caseinate (Na-Cas), and exposed to conditions simulating the human upper gastrointestinal tract. In particular, we looked at how the kinetics of proteolysis was affected by adsorption to an oil-water interface in emulsion and whether the proteolysis and the emulsion stability could be manipulated by enzymatic structuring of the interface. After cross-linking with the enzyme transglutaminase, the protein was digested with use of an in vitro model of gastro-duodenal proteolysis in the presence or absence of physiologically relevant surfactants (phosphatidylcholine, PC; bile salts, BS). Significant differences were found between the rates of digestion of Na-Cas cross-linked in emulsion (adsorbed protein) and in solution. In emulsion, the digestion of a population of polypeptides of M(r) ca. 50-100 kDa was significantly retarded through the gastric digestion. The persistent interfacial polypeptides maintained the original emulsion droplet size and prevented the system from phase separating. Rapid pepsinolysis of adsorbed, non-cross-linked Na-Cas and its displacement by PC led to emulsion destabilization. These results suggest that structuring of emulsions by enzymatic cross-linking of the interfacial protein may affect the phase behavior of emulsion in the stomach and the gastric digestion rate in vivo. Measurements of ζ-potential revealed that BS displaced the remaining protein from the oil droplets during the simulated duodenal phase of digestion. Diffusion of the postdigestion emulsion droplets through ex vivo porcine intestinal mucus was only significant in the presence of BS due to the high negative charge these biosurfactants imparted to the droplets. This implies that the electrostatic repulsion produced can prevent the droplets from being trapped by the mucus matrix and facilitate their transport across the small intestine mucosal barrier.
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Affiliation(s)
- Adam Macierzanka
- Institute of Food Research, Norwich Research Park, Colney Lane, Norwich NR4 7UA, United Kingdom.
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20
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Round AN, Rigby NM, Garcia de la Torre A, Macierzanka A, Mills ENC, Mackie AR. Lamellar structures of MUC2-rich mucin: a potential role in governing the barrier and lubricating functions of intestinal mucus. Biomacromolecules 2012; 13:3253-61. [PMID: 22978827 DOI: 10.1021/bm301024x] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mucus is a ubiquitous feature of mammalian wet epithelial surfaces, where it lubricates and forms a selective barrier that excludes a range of particulates, including pathogens, while hosting a diverse commensal microflora. The major polymeric component of mucus is mucin, a large glycoprotein formed by several MUC gene products, with MUC2 expression dominating intestinal mucus. A satisfactory answer to the question of how these molecules build a dynamic structure capable of playing such a complex role has yet to be found, as recent reports of distinct layers of chemically identical mucin in the colon and anomalously rapid transport of nanoparticles through mucus have emphasized. Here we use atomic force microscopy (AFM) to image a MUC2-rich mucus fraction isolated from pig jejunum. In the freshly isolated mucin fraction, we find direct evidence for trigonally linked structures, and their assembly into lamellar networks with a distribution of pore sizes from 20 to 200 nm. The networks are two-dimensional, with little interaction between lamellae. The existence of persistent cross-links between individual mucin polypeptides is consistent with a non-self-interacting lamellar model for intestinal mucus structure, rather than a physically entangled polymer network. We only observe collapsed entangled structures in purified mucin that has been stored in nonphysiological conditions.
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Affiliation(s)
- Andrew N Round
- School of Pharmacy, University of East Anglia , Norwich Research Park, Norwich, UK.
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21
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Bøgh KL, Barkholt V, Rigby NM, Mills ENC, Madsen CB. Digested Ara h 1 loses sensitizing capacity when separated into fractions. J Agric Food Chem 2012; 60:2934-2942. [PMID: 22364549 DOI: 10.1021/jf2052306] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The major peanut allergen Ara h 1 is an easily digestible protein under physiological conditions. The present study revealed that pepsin digestion products of Ara h 1 retained the sensitizing potential in a Brown Norway rat model, while this sensitizing capacity was lost by separating the digest into fractions by gel permeation chromatography. Protein chemical analysis showed that the peptide composition as well as the aggregation profiles of the fractions of Ara h 1 digest differed from that of the whole pool. These results indicate that the sensitizing capacity of digested Ara h 1 is a consequence of the peptides being in an aggregated state resembling the intact molecule or that most peptides of the digests need to be present in the same solution, having a synergistic or adjuvant effect and thereby augmenting the immune response against other peptides.
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Affiliation(s)
- Katrine L Bøgh
- National Food Institute, Division of Toxicology and Risk Assessment, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark.
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22
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Blanc F, Vissers YM, Adel-Patient K, Rigby NM, Mackie AR, Gunning AP, Wellner NK, Skov PS, Przybylski-Nicaise L, Ballmer-Weber B, Zuidmeer-Jongejan L, Szépfalusi Z, Ruinemans-Koerts J, Jansen APH, Bernard H, Wal JM, Savelkoul HFJ, Wichers HJ, Mills ENC. Boiling peanut Ara h 1 results in the formation of aggregates with reduced allergenicity. Mol Nutr Food Res 2011; 55:1887-94. [DOI: 10.1002/mnfr.201100251] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 08/26/2011] [Accepted: 08/28/2011] [Indexed: 11/09/2022]
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23
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Vissers YM, Blanc F, Skov PS, Johnson PE, Rigby NM, Przybylski-Nicaise L, Bernard H, Wal JM, Ballmer-Weber B, Zuidmeer-Jongejan L, Szépfalusi Z, Ruinemans-Koerts J, Jansen APH, Savelkoul HFJ, Wichers HJ, Mackie AR, Mills CEN, Adel-Patient K. Effect of heating and glycation on the allergenicity of 2S albumins (Ara h 2/6) from peanut. PLoS One 2011; 6:e23998. [PMID: 21901150 PMCID: PMC3162016 DOI: 10.1371/journal.pone.0023998] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Accepted: 07/29/2011] [Indexed: 11/19/2022] Open
Abstract
Background Peanut allergy is one of the most common and severe food allergies, and processing is known to influence the allergenicity of peanut proteins. We aimed to establish the effect of heating and glycation on the IgE-binding properties and biological activity of 2S albumins (Ara h 2/6) from peanut. Methodology/Principal Findings Native Ara h 2/6 was purified from raw peanuts and heated in solution (15 min, 110°C) in the presence or absence of glucose. Ara h 2 and 6 were also purified from roasted peanut. Using PBMC and sera from peanut-allergic patients, the cellular proliferative potency and IgE reactivity (reverse EAST inhibition) and functionality (basophil degranulation capacity) of allergens were assessed. Heating Ara h 2/6 at 110°C resulted in extensive denaturation, hydrolysis and aggregation of the protein, whilst Ara h 2 and 6 isolated from roasted peanut retained its native conformation. Allergen stimulation of PBMC induced proliferation and Th2 cytokine secretion which was unaffected by thermal processing. Conversely, IgE reactivity and functionality of Ara h 2/6 was decreased by heating. Whilst heating-glycation further reduced the IgE binding capacity of the proteins, it moderated their loss of histamine releasing capacity. Ara h 2 and 6 purified from roasted peanut demonstrated the same IgE reactivity as unheated, native Ara h 2/6. Conclusions/Significance Although no effect of processing on T-cell reactivity was observed, heat induced denaturation reduced the IgE reactivity and subsequent functionality of Ara h 2/6. Conversely, Ara h 2 and 6 purified from roasted peanut retained the structure and IgE reactivity/functionality of the native protein which may explain the allergenic potency of this protein. Through detailed molecular study and allergenicity assessment approaches, this work then gives new insights into the effect of thermal processing on structure/allergenicity of peanut proteins.
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Affiliation(s)
- Yvonne M Vissers
- Cell Biology and Immunology Group, Wageningen University and Research Centre, Wageningen, The Netherlands
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24
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Bossios A, Theodoropoulou M, Mondoulet L, Rigby NM, Papadopoulos NG, Bernard H, Adel-Patient K, Wal JM, Mills CE, Papageorgiou P. Effect of simulated gastro-duodenal digestion on the allergenic reactivity of beta-lactoglobulin. Clin Transl Allergy 2011; 1:6. [PMID: 22410304 PMCID: PMC3339358 DOI: 10.1186/2045-7022-1-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 08/09/2011] [Indexed: 02/02/2023] Open
Abstract
Background Cow's milk (CM) allergy affects about 2% of infants. The allergenicity of dietary proteins, including those from CM, has been related to their digestibility although the generality of the link and its causality remains to be demonstrated. In this study we use an in vitro digestion system, to investigate the digestibility of β-lactoglobulin (blg) during gastrointestinal transit and to assess the impact of this process on blg allergenic reactivity in CM allergic children. Methods Blg digesta were prepared using an in vitro digestion protocol simulating either gastric digestion alone or followed by duodenal digestion with or without phosphatidylcholine (PC). Biochemical analysis of blg digesta was performed by SDS-PAGE and their concentration was measured by a sandwich ELISA. Assessment of their allergenic reactivity was done in vitro by EAST inhibition, specific basophil activation (basotest) and lymphocyte proliferation (PCNA-flow cytometry) assays using sera and cells from patients allergic to blg and in vivo by skin prick testing (SPT) of these patients. Results Blg was only broken down to smaller peptides after gastro-duodenal digestion although a sizeable amount of intact protein still remained. Digestion did not modify the IgE binding capacity of blg except for gastro-duodenal digestion performed in the absence of PC. These results are consistent with the quantity of intact blg remaining in the digesta. Overall both gastric and gastroduodenal digestion enhanced activation of sensitized basophils and proliferation of sensitized lymphocytes by blg. However, there was a tendency towards reduction in mean diameter of SPT following digestion, the PC alone during phase 1 digestion causing a significant increase in mean diameter. Conclusions Digestion did not reduce the allergenic reactivity of blg to a clinically insignificant extent, PC inhibiting digestion and thereby protecting blg allergenic reactivity. SPT reactivity was reduced compared to blg immunoreactivity in in vitro tests.
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Affiliation(s)
- Apostolos Bossios
- Athens University, P. & A. Kyriakou Children's Hospital, Athens, Greece.,Krefting Research Centre, Department of Internal Medicine, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Maria Theodoropoulou
- Athens University, P. & A. Kyriakou Children's Hospital, Athens, Greece.,Thessaly University Hospital, Larissa, Greece
| | - Lucie Mondoulet
- Lab d'Immuno-Allergie Alimentaire, INRA-CEA, Saclay, France.,DBV Technologies, 92220, Bagneux, France
| | - Neil M Rigby
- Institute of Food Research, Norwich Research Park, Colney NR4 7UA UK
| | | | - Hervé Bernard
- Lab d'Immuno-Allergie Alimentaire, INRA-CEA, Saclay, France
| | | | | | - Clare En Mills
- Institute of Food Research, Norwich Research Park, Colney NR4 7UA UK
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25
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Vissers YM, Iwan M, Adel-Patient K, Stahl Skov P, Rigby NM, Johnson PE, Mandrup Müller P, Przybylski-Nicaise L, Schaap M, Ruinemans-Koerts J, Jansen APH, Mills ENC, Savelkoul HFJ, Wichers HJ. Effect of roasting on the allergenicity of major peanut allergens Ara h 1 and Ara h 2/6: the necessity of degranulation assays. Clin Exp Allergy 2011; 41:1631-42. [PMID: 21801247 DOI: 10.1111/j.1365-2222.2011.03830.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Peanuts are often consumed after roasting, a process that alters the three-dimensional structure of allergens and leads to Maillard modification. Such changes are likely to affect their allergenicity. OBJECTIVE We aimed to establish the effect of thermal treatment mimicking the roasting process on the allergenicity of Ara h 1 and a mix of 2S albumins from peanut (Ara h 2/6). METHODS Ara h 1 and Ara h 2/6 were purified from raw peanuts and heated in a dry form for 20 min at 145°C in the presence (R+g) or absence (R-g) of glucose, and soluble proteins were then extracted. Sera obtained from 12 well-characterized peanut-allergic patients were used to assess the IgE binding and degranulation capacities of the allergens. RESULTS Extensive heating at low moisture resulted in the hydrolysis of both Ara h 1 and Ara h 2/6. However, in contrast to Ara h 2/6, soluble R+g Ara h 1 formed large aggregates. Although the IgE-binding capacity of R+g and R-g Ara h 1 was decreased 9000- and 3.6-fold, respectively, compared with native Ara h 1, their capacity to elicit mediator release was increased. Conversely, both the IgE-binding capacity and the degranulation capacity of R-g Ara h 2/6 were 600-700-fold lower compared with the native form, although the presence of glucose during heating significantly moderated these losses. CONCLUSIONS AND CLINICAL RELEVANCE Extensive heating reduced the degranulation capacity of Ara h 2/6 but significantly increased the degranulation capacity of Ara h 1. This observation can have important ramifications for component-resolved approaches for diagnosis and demonstrates the importance of investigating the degranulation capacity in addition to IgE reactivity when assessing the effects of food processing on the allergenicity of proteins.
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Affiliation(s)
- Y M Vissers
- Cell Biology and Immunology Group, Wageningen University and Research Centre, Wageningen, The Netherlands.
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26
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Macierzanka A, Bordron F, Rigby NM, Mills EC, Lille M, Poutanen K, Mackie AR. Transglutaminase cross-linking kinetics of sodium caseinate is changed after emulsification. Food Hydrocoll 2011. [DOI: 10.1016/j.foodhyd.2010.07.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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27
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Rigby NM, Sancho AI, Salt LJ, Foxall R, Taylor S, Raczynski A, Cochrane SA, Crevel RWR, Mills ENC. Quantification and partial characterization of the residual protein in fully and partially refined commercial soybean oils. J Agric Food Chem 2011; 59:1752-1759. [PMID: 21250696 DOI: 10.1021/jf103560h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A method has been developed to determine residual protein in refined oils, a potential trigger of allergic reactions. High-pH bicarbonate or borate buffers were found to be the most effective extractants, residual oil protein comprising a mixture of proteins of M(r) 6000-100000. Extracted protein could be quantified with superior precision using 3-(4-carboxybenzoyl)quinolone-2-carboxaldehyde (CBQCA). Residual protein content determined in a set of oils using the borate extraction-CBQCA assay was positively correlated with contents determined using a bicarbonate-total amino acid analysis method. Oil refining substantially reduced the oil protein content determined by the borate-CBQCA assay with neutralized/refined, bleached, and deodorized (fully refined) oils containing 62-265 ng/g oil, whereas crude un-degummed oils contained 86000-87900 ng/g of protein. These analyses and published data on cumulative threshold doses for soybean suggest that even the most sensitive individuals would need to consume at least 50 g of highly refined oil to experience subjective symptoms.
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Affiliation(s)
- Neil M Rigby
- Institute of Food Research , Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom
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28
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Kroghsbo S, Bøgh KL, Rigby NM, Mills ENC, Rogers A, Madsen CB. Sensitization with 7S globulins from peanut, hazelnut, soy or pea induces IgE with different biological activities which are modified by soy tolerance. Int Arch Allergy Immunol 2011; 155:212-24. [PMID: 21282960 DOI: 10.1159/000321200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 09/08/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND It is not known why some foods sensitizing via the gastrointestinal tract are prevalent allergenic foods and others are not. Eating habits, processing, and the food matrix have been suggested to influence the allergenicity of a given food. Factors related to protein structure, such as stability to digestion, have also been suggested. 7S globulins from peanut, hazelnut, soy, and pea were studied to determine whether related proteins would induce a similar sensitization when removed from their 'normal' matrix. METHODS Brown Norway rats (soy tolerant or nontolerant) were immunized i.p. 3 times with 100 μg purified peanut, hazelnut, soy, or pea 7S without adjuvant. Sera were analyzed for specific antibodies by different ELISAs (IgG1, IgG2a, and IgE), inhibition ELISA, and rat basophilic leukemia cell assay. RESULTS The 4 related 7S globulins induced a response with an almost identical level of specific antibodies, but peanut 7S induced IgE of higher avidity than hazelnut and pea 7S which, again, had a higher avidity than IgE induced by soy 7S. Soy tolerance reduced the functionality of IgE without influencing antibody titers. CONCLUSIONS Although the 4 7S globulins are structurally related allergens, they induce antibodies with different antigen-binding characteristics. Peanut 7S induces IgE of a higher avidity than hazelnut and pea 7S which, again, has a higher avidity than IgE induced by soy 7S. We also show that soy tolerance influences the function of antibodies to peanut 7S. These findings may help explain how antibodies of different clinical significances can develop in different individuals sensitized to the same allergen.
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Affiliation(s)
- Stine Kroghsbo
- National Food Institute, Technical University of Denmark, Søborg, Denmark.
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29
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Round AN, Rigby NM, MacDougall AJ, Morris VJ. A new view of pectin structure revealed by acid hydrolysis and atomic force microscopy. Carbohydr Res 2010; 345:487-97. [DOI: 10.1016/j.carres.2009.12.019] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 12/11/2009] [Accepted: 12/18/2009] [Indexed: 10/20/2022]
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Clare Mills EN, Gao C, Wilde PJ, Rigby NM, Wijesinha-Bettoni R, Johnson VE, Smith LJ, Mackie AR. Partially Folded Forms of Barley Lipid Transfer Protein Are More Surface Active. Biochemistry 2009; 48:12081-8. [DOI: 10.1021/bi901328f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- E. N. Clare Mills
- Institute of Food Research, Norwich Research Park, Colney NR4 7UA, U.K
| | - Chunli Gao
- Institute of Food Research, Norwich Research Park, Colney NR4 7UA, U.K
| | - Peter J. Wilde
- Institute of Food Research, Norwich Research Park, Colney NR4 7UA, U.K
| | - Neil M. Rigby
- Institute of Food Research, Norwich Research Park, Colney NR4 7UA, U.K
| | - Ramani Wijesinha-Bettoni
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, U.K
| | - Victoria E. Johnson
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, U.K
| | - Lorna J. Smith
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, U.K
| | - Alan R. Mackie
- Institute of Food Research, Norwich Research Park, Colney NR4 7UA, U.K
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Mills ENC, Sancho AI, Rigby NM, Jenkins JA, Mackie AR. Impact of food processing on the structural and allergenic properties of food allergens. Mol Nutr Food Res 2009; 53:963-9. [PMID: 19603402 DOI: 10.1002/mnfr.200800236] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This article reviews recent studies that address one of the major unanswered questions in food allergy research: what attributes of food or food proteins contribute to or enhance food allergenicity?
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Affiliation(s)
- E N Clare Mills
- Institute of Food Research, Norwich Research Park, Colney Norwich, NR4 7UA UK.
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Abstract
BACKGROUND Food allergies are a public health issue of growing concern, with peanuts in particular being associated with severe reactions. The peanut allergen, Ara h 1, belongs to the cupin plant food allergen family, which, unlike other structural families, appears to be broken down rapidly following gastrointestinal digestion. OBJECTIVE Using Ara h 1 as a model allergen, the ability of digested protein to sensitize has been investigated. METHODS Ara h 1 was purified from whole roasted peanuts. Intact Ara h 1 was digested in an in vitro model, simulating the human gastrointestinal digestion process. Digestion products were analysed for peptide sizes and their ability to aggregate. Brown Norway (BN) rats, used as an animal model, were immunized with purified intact Ara h 1 or the gastrointestinal digestion products thereof. The sensitizing capacity was evaluated by analyses of specific antibody (IgG1, IgG2a and IgE) responses and ability to trigger mediator release of rat basophilic leukaemia (RBL)-2H3 cells. RESULTS The present study showed that Ara h 1 was broken down, resulting in peptide fragments of sizes<2.0 kDa, of which approximately 50% was in aggregated complexes of Mr up to 20 kDa. Ara h 1 digesta were shown to have sensitizing capacity in BN rats, being capable of inducing specific IgG and IgE antibodies. The IgE response was functional, having the capacity to induce specific degranulation of RBL cells. CONCLUSION From this study, it can be concluded that lability of a food allergen to gastrointestinal digestion does not necessarily abrogate its allergenic sensitizing potential.
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Affiliation(s)
- K L Bøgh
- Department of Toxicology and Risk Assessment, National Food Institute, Technical University of Denmark, Søborg, Denmark.
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33
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Mandalari G, Mackie AM, Rigby NM, Wickham MSJ, Mills ENC. Physiological phosphatidylcholine protects bovine β-lactoglobulin from simulated gastrointestinal proteolysis. Mol Nutr Food Res 2009; 53 Suppl 1:S131-9. [DOI: 10.1002/mnfr.200800321] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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34
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Gaier S, Oberhuber C, Hemmer W, Radauer C, Rigby NM, Marsh JT, Mills CEN, Shewry PR, Hoffmann-Sommergruber K. Pru p 3 as a marker for symptom severity for patients with peach allergy in a birch pollen environment. J Allergy Clin Immunol 2009; 124:166-7. [PMID: 19368964 DOI: 10.1016/j.jaci.2009.02.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 01/29/2009] [Accepted: 02/09/2009] [Indexed: 11/30/2022]
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35
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Gaier S, Marsh J, Oberhuber C, Rigby NM, Lovegrove A, Alessandri S, Briza P, Radauer C, Zuidmeer L, van Ree R, Hemmer W, Sancho AI, Mills C, Hoffmann-Sommergruber K, Shewry PR. Purification and structural stability of the peach allergens Pru p 1 and Pru p 3. Mol Nutr Food Res 2009; 52 Suppl 2:S220-9. [PMID: 18384093 DOI: 10.1002/mnfr.200700274] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pru p 1 (a Bet v 1 homologue) and Pru p 3 (a nonspecific lipid transfer protein; nsLTP) are major allergenic proteins in peach fruit, but differ in their abundance and stability. Pru p 1 has low abundance and is highly labile and was purified after expression as a recombinant protein in Escherichia coli. Pru p 3 is highly abundant in peach peel and was purified by conventional methods. The identities of the proteins were confirmed by sequence analysis and their masses determined by MS analysis. The purified proteins reacted with antisera against related allergens from other species: Pru p 1 with antiserum to Bet v 1 and Pru p 3 with antiserum to Mal d 3 (from apple). The presence of secondary and tertiary structure was demonstrated by circular dichroism (CD) and high field NMR spectroscopy. CD spectroscopy also showed that the two proteins differed in their stability at pH 3 and in their ability to refold after heating to 95 degrees C. Thus, Pru p 1 was unfolded at pH 3 even at 25 degrees C but was able to refold after heating to 95 degrees C at pH 7.5. In contrast, Pru p 3 was unable to refold after heating under neutral conditions but readily refolded after heating at pH 3.
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Affiliation(s)
- Sonja Gaier
- Department of Pathophysiology, Medical University of Vienna, Vienna, Austria
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36
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Rigby NM, Marsh J, Sancho AI, Wellner K, Akkerdaas J, van Ree R, Knulst A, Fernández-Rivas M, Brettlova V, Schilte PP, Summer C, Pumphrey R, Shewry PR, Mills ENC. The purification and characterisation of allergenic hazelnut seed proteins. Mol Nutr Food Res 2009; 52 Suppl 2:S251-61. [PMID: 19006093 DOI: 10.1002/mnfr.200800083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A lipid transfer protein (LTP, Cor a 8) together with the 11S (Cor a 9) and 7S seed storage globulins (Cor a 11) are major food allergens present in hazelnut. Methods are described for their purification and characterisation using in-gel tryptic digestion mass spectrometry to confirm their identities and circular dichroism and Fourier-transform infrared spectroscopies to demonstrate that they are authentically folded. Preliminary immunochemical studies have also confirmed that the purified preparations retain their immunological properties in terms of immunoglobulin E binding, determined by immunoblotting using serum from hazelnut allergic patients. These preparations form a basis for development of improved methods of diagnosis of food allergy based on the concept of component-resolved diagnosis.
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Burnett GR, Rigby NM, Mills ENC, Belton PS, Fido RJ, Tatham AS, Shewry PR. Characterization of the emulsification properties of 2S albumins from sunflower seed. J Colloid Interface Sci 2007; 247:177-85. [PMID: 16290454 DOI: 10.1006/jcis.2001.8093] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2001] [Accepted: 11/08/2001] [Indexed: 11/22/2022]
Abstract
The ability of 2S albumins from sunflower seeds to stabilize oil-in-water emulsions has been investigated, demonstrating that one of the proteins (SFA8) effectively stabilizes emulsions, while another (SF-LTP) does not stabilize emulsions. The surface tension and surface dilation viscosity of these two proteins were measured, rationalizing the emulsifying ability of SFA8 in terms of its ability to form a strongly elastic monolayer at interfaces. The secondary structure changes that occur upon adsorption of SFA8 to the oil/water interface have also been studied by fluorescence, circular dichroism (CD), and Fourier-transform infrared (FT-IR) spectroscopy. It was found that the beta-sheet content of the protein increased upon adsorption at the expense of alpha-helix and random structure. Moreover, FT-IR measurements indicate the presence of intermolecular beta-sheet formation upon adsorption. Fluorescence studies with an oil-soluble fluorescence quencher indicate that the single tryptophan residue present in SFA8 may become located in the oil-phase of the emulsion. This residue is thought to be partially buried in the native protein, and these data suggest that changes in the polypeptide region flanking this residue may play an important role in the molecular rearrangement that occur on or following adsorption to the oil/water interface.
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Affiliation(s)
- Gary R Burnett
- Institute of Food Research, Norwich Research Park, Colney Lane, Norwich, NR4 7UA, United Kingdom.
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38
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Sancho AI, Foxall R, Rigby NM, Browne T, Zuidmeer L, van Ree R, Waldron KW, Mills ENC. Maturity and storage influence on the apple (Malus domestica) allergen Mal d 3, a nonspecific lipid transfer protein. J Agric Food Chem 2006; 54:5098-104. [PMID: 16819922 DOI: 10.1021/jf0530446] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Consumption of apples can provoke severe allergic reactions, in susceptible individuals, due to the presence of the allergen Mal d 3, a nonspecific lipid transfer protein, found largely in the fruit skin. Levels of Mal d 3 were determined in peel as a function of apple cultivar, position of the fruit growing on the tree, apple maturity, and postharvest storage by ELISA. As the apples mature, Mal d 3 levels increased, although the rate was dependent on cultivar and tree position. During storage, levels of Mal d 3 decreased in all cultivars (cvs. Cox, Jonagored, and Gala), the rate of overall decrease being greatest under controlled atmosphere conditions. There was no correlation between Mal d 3 levels and total apple peel protein, indicating specific alterations in Mal d 3 expression. Thus pre- and postharvest treatments (i.e., storage) can modify the allergen load in apple peel, the highest levels being found in overly mature and freshly harvested fruits.
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Affiliation(s)
- Ana I Sancho
- Institute of Food Research, Norwich Research Park, Colney, Norwich NR47UA, United Kingdom.
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39
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Sancho AI, Rigby NM, Zuidmeer L, Asero R, Mistrello G, Amato S, González-Mancebo E, Fernández-Rivas M, van Ree R, Mills ENC. The effect of thermal processing on the IgE reactivity of the non-specific lipid transfer protein from apple, Mal d 3. Allergy 2005; 60:1262-8. [PMID: 16134992 DOI: 10.1111/j.1398-9995.2005.00876.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [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: 11/30/2022]
Abstract
BACKGROUND Non-specific lipid transfer proteins (LTPs) are involved in allergy to fresh and processed fruits. We have investigated the effect of thermal treatment and glycation on the physico-chemical and IgE-binding properties of the LTP from apple (Mal d 3). METHODS Mal d 3 was purified from apple peel and the effect of heating in the absence and presence of glucose investigated by CD spectroscopy, electrospray and MALDI-TOF mass spectrometry. IgE reactivity was determined by RAST and immunoblot inhibition, SPT and basophil histamine release test. RESULTS The identity and IgE reactivity of purified Mal d 3 was confirmed. Mild heat treatment (90 degrees C, 20 min) in the absence or presence of glucose did not alter its IgE reactivity. More severe heat treatment (100 degrees C, 2 h) induced minor changes in protein structure, but a significant decrease in IgE-binding (30-fold) and biological activity (100- to 1000-fold). Addition of glucose resulted in up to four glucose residues attached to Mal d 3 and only a 2- and 10-fold decrease of IgE-binding and biological activity, respectively. CONCLUSIONS Only severe heat treatment caused a significant decrease in the allergenicity of Mal d 3 but glycation had a protective effect. The presence of sugars in fruits may contribute to the thermostability of the allergenic activity of LTP in heat-processed foods.
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Affiliation(s)
- A I Sancho
- Institute of Food Research, Norwich Research Park, Colney, Norwich, UK
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40
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Moreno FJ, Jenkins JA, Mellon FA, Rigby NM, Robertson JA, Wellner N, Clare Mills EN. Mass spectrometry and structural characterization of 2S albumin isoforms from Brazil nuts (Bertholletia excelsa). Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2004; 1698:175-86. [PMID: 15134650 DOI: 10.1016/j.bbapap.2003.11.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2003] [Revised: 09/03/2003] [Accepted: 11/13/2003] [Indexed: 11/26/2022]
Abstract
Proteomic approaches have been used to characterise the main 2S albumin isoforms from Brazil nuts (Bertholletia excelsa). Whilst most isoforms ( approximately 10 discrete protein species) exhibited molecular masses of around 12 kDa with a high amino acid sequence homology, important charge heterogeneity was found, with pIs varying between 4.6 and 6.6, with one >or=7.0. Proteomic analysis showed that these corresponded to a total of six National Center for Biotechnology Information (NCBI) accessions and that three isoforms had been purified to homogeneity corresponding to gi/384327, 112754 and 99609. The latter sequence corresponds to an isoform, previously only identified at the nucleotide sequence level, had a slightly higher molecular weight (13.4 kDa), and with noticeable differences in the primary structure. Proteins corresponding to six different NCBI accessions were identified, the heterogeneity of which had been increased by posttranslational processing. Evidence was found of cyclization of the N-terminal glutamine residue in two isoforms, together with ragged C-termini, indicative of carboxypeptidase activity within the vacuole following posttranslational processing. No evidence of glycosylation was found. Circular dichroism (CD) and Fourier transform-infrared (FT-IR) spectroscopy indicated all the studied isoforms were predominantly alpha-helical in nature, but that the Mr 13400 species was structurally distinct, with a higher proportion of alpha-helical structure.
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Affiliation(s)
- F Javier Moreno
- Institute of Food Research, Norwich Research Park, Colney Lane, Norwich NR4 7UA, UK.
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41
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Affiliation(s)
- Roger J Fido
- Long Ashton Research Station, Department of Agricultural Sciences, University of Bristol, UK
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42
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Abstract
The swelling of tomato pectin and isolated tomato pericarp cell wall material was investigated in aqueous media under different ionic conditions, pH, and external osmotic stress. Conditions were chosen to include those that would be encountered in vivo. Swelling in these systems was strongly influenced by the polyelectrolyte nature of the polymer and the extent of cross-linking with divalent counterions.
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Affiliation(s)
- A J MacDougall
- Food Biopolymer Section, Institute of Food Research, Norwich Laboratory, Norwich Research Park, Colney, Norwich NR4 7UA, U.K.
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43
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Craig ID, Parker R, Rigby NM, Cairns P, Ring SG. Maillard reaction kinetics in model preservation systems in the vicinity of the glass transition: experiment and theory. J Agric Food Chem 2001; 49:4706-4712. [PMID: 11600011 DOI: 10.1021/jf0100752] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Rates of reactant consumption for the Maillard reaction between lysine and glucose were measured for a noncrystallizing trehalose-sucrose-water matrix in the glass transition region. At temperatures above the glass transition temperature (T(g)), the consumption rates showed Arrhenius temperature dependence with activation energies of 135 and 140 kJ mol(-1) for lysine and glucose, respectively. Finite reaction rates were observed for glassy samples that were faster than that of one of the nonglassy samples. A comparison of experimental results with predicted diffusion-controlled reaction rate constants indicated that the reaction was reaction-controlled at temperatures above T(g) and approached the diffusion-influenced regime in the glassy state. The needs for further research on reactant diffusivity, the theory of the orientation dependence of reactivity, and a detailed understanding of the reaction mechanism and kinetics were identified.
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Affiliation(s)
- I D Craig
- Food Materials Science Division, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK
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44
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MacDougall AJ, Brett GM, Morris VJ, Rigby NM, Ridout MJ, Ring SG. The effect of peptide-pectin interactions on the gelation behaviour of a plant cell wall pectin. Carbohydr Res 2001; 335:115-26. [PMID: 11567642 DOI: 10.1016/s0008-6215(01)00221-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [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: 11/20/2022]
Abstract
The effect of basic peptides on the gelation of a pectin from the cell wall of tomato was examined through the determination of gel stiffness, and swelling behaviour of the gel in water. Poly-L-lysine, poly-L-arginine, and a synthetic peptide, designed to mimic a sequence of basic amino acids found in a plant cell wall extensin, act as crosslinking agents. Circular dichroism studies on the interaction of synthetic extensin peptides with sodium polygalacturonate demonstrated that a conformational change was induced as a result of their complexation. In addition to their effect as crosslinking agents, the polycationic peptides reduced the swelling of the pectin network in water.
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Affiliation(s)
- A J MacDougall
- Division of Food Materials Science, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK.
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45
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Needs PW, Rigby NM, Ring SG, MacDougall AJ. Specific degradation of pectins via a carbodiimide-mediated Lossen rearrangement of methyl esterified galacturonic acid residues. Carbohydr Res 2001; 333:47-58. [PMID: 11423110 DOI: 10.1016/s0008-6215(01)00120-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [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: 11/24/2022]
Abstract
A specific, chemical degradation of the methyl esterified galacturonic acid residues of pectins is described. These residues are converted, with hydroxylamine, to hydroxamic acids, and then, with a carbodiimide, to isoureas; the latter undergo a Lossen rearrangement on alkaline hydrolysis. The isocyanates formed are hydrolysed to 5-aminoarabinopyranose derivatives, which spontaneously ring open to give 1,5-dialdehydes. The latter are reduced, in situ, to avoid peeling reactions, with sodium borohydride to give substituted arabitol residues. Thus, overall, partially esterified pectins are specifically cleaved to generate a series of oligogalacturonic acids bearing an arabitol residue as aglycone. Analysis of oligomers so generated discloses the pattern of contiguous nonesterification in a variety of pectins of differing degrees of esterification. Other potential applications are described.
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Affiliation(s)
- P W Needs
- Nutrition, Health, and Consumer Science Division, Institute of Food Research, Norwich Research Park, Colney Lane, Norwich NR4 7UA, UK.
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46
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Round AN, Rigby NM, MacDougall AJ, Ring SG, Morris VJ. Investigating the nature of branching in pectin by atomic force microscopy and carbohydrate analysis. Carbohydr Res 2001; 331:337-42. [PMID: 11383904 DOI: 10.1016/s0008-6215(01)00039-8] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [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: 11/18/2022]
Abstract
Atomic force microscopy (AFM) has been used to investigate the nature of the long branches attached to pectin which were described in a previous report [Round, A. N.; MacDougall, A. J.; Ring, S. G.; Morris, V. J. Carbohydr. Res. 1997, 303, 251-253]. Analysis of the AFM images and comparison with neutral sugar and linkage analyses of the two pectin fractions suggest that the distribution and total amount of branches observed do not correspond with the pattern of neutral sugar distribution. It is thus postulated that the long chains consist of polygalacturonic acid, attached via an as yet undetermined linkage to the pectin backbone, with the neutral sugars present as short, undetected branches. This explanation would have important implications for the nature of 'in situ' pectin networks within plant cell walls and models of gelation in commercial extracted pectin, and the existence of significant branching will markedly influence the viscosity of extracted pectins.
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Affiliation(s)
- A N Round
- Institute of Food Research, Norwich Research Park, Colney, UK.
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47
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Abstract
Oligogalacturonates were produced by the limited enzymic hydrolysis of polygalacturonic acid and purified by ion-exchange chromatography. The fractions obtained were of limited polydispersity, determined by analytical ion-exchange chromatography. Oligomers with an average degree of polymerization of 10-15 were readily crystallized from aqueous salt solutions at neutral pH as single crystals. Crystal morphology of the salts examined, Na+, K+ and Ca2+ were characteristic of the salt. The wide-angle X-ray diffraction patterns obtained for the sodium salt were consistent with published fibre diffraction data of this salt form.
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Affiliation(s)
- N M Rigby
- Food Quality and Materials Science, Institute of Food Research, Norwich Laboratory, Colney, UK.
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48
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Gunning YM, Parker R, Ring SG, Rigby NM, Wegg B, Blake A. Phase behavior and component partitioning in low water content amorphous carbohydrates and their potential impact on encapsulation of flavors. J Agric Food Chem 2000; 48:395-399. [PMID: 10691646 DOI: 10.1021/jf9904158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The compositions at which amorphous ethanol-maltose-water mixtures exhibit liquid-liquid separation have been determined in the temperature range from 20 to 80 degrees C. At water contents below approximately 20% w/w two phases were observed, with the maltose-rich phase slightly richer in water. Partition coefficients of organic nonelectrolytes ranging in hydrophobicity from 1, 2-ethanediol and 1,2-propanediol to benzyl alcohol and propyl acetate have been measured for octanol/sorbitol, benzyl alcohol/sorbitol, and 1-butanol/sorbitol mixtures. Linear correlations were found between the log partition coefficients in the various solvent systems. Replacing water with sorbitol results in more organic partitioning into the octanol. Replacing octanol with benzyl alcohol or 1-butanol also results in more organic partitioning into the hydrophobic phase. The results establish a relationship with partition coefficients for octanol/water mixtures, which are well studied experimentally and for which predictive approaches exist. The implications of these results for flavor retention and encapsulation are discussed.
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Affiliation(s)
- Y M Gunning
- Food Materials Science Division, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom
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49
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Macdougall AJ, Rigby NM, Needs PW, Selvendran RR. Movement and metabolism of oligogalacturonide elicitors in tomato shoots. Planta 1992; 188:566-574. [PMID: 24178390 DOI: 10.1007/bf00197050] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/23/1992] [Indexed: 06/02/2023]
Abstract
We have studied the movement and metabolism of oligogalacturonides through shoots of tomato (Lycopersicon esculentum L. cv Rutgers). Oligomers of polygalacturonic acid were prepared by enzyme digestion and gel filtration. These were end-reduced with [(3)H]NaBH4, using an improved reaction method, to yield oligoalditols. The radiolabelled oligomer of degree of polymerisation 6 was supplied to tomato shoots through their transpiration stream. Analysis of the distribution of radiolabel in the plant, and TLC of radiolabelled material recovered from the plant revealed the following: a) material recovered from the plant could be identified as an oligogalacturonide from its behaviour on TLC and susceptibility to digestion with polygalacturonase; b) end-reduced oligogalacturonides moved freely through the plant and were not complexed to high-molecularweight compounds and immobilised; c) during passage through the plant, modifications to the oligogalacturonide occurred, presumably as a consequence of metabolism in the apoplastic space. We found evidence of i) esterification of the molecule, and ii) shortening of the oligogalacturonide chain. The results show that in the assay for protease-inhibitor-inducing factor using cut shoots, oligogalacturonide elicitors can move into the leaves and act directly on the cells producing protease inhibitor.
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Affiliation(s)
- A J Macdougall
- AFRC Institute of Food Research, Norwich Laboratory, Norwich Research Park, Colney, Norwich NR4 7UA, UK
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50
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Coxon DT, Peers KE, Rigby NM. Selective formation of dihydroperoxides in the α-tocopherol inhibited autoxidation of methyl linolenate. ACTA ACUST UNITED AC 1984. [DOI: 10.1039/c39840000067] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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