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Sägesser C, Kallfelz JM, Boulos S, Hammer L, Böcker L, Portmann R, Nyström L, Mathys A. A novel approach for the protein determination in food-relevant microalgae. Bioresour Technol 2023; 390:129849. [PMID: 37813318 DOI: 10.1016/j.biortech.2023.129849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/06/2023] [Accepted: 10/06/2023] [Indexed: 10/11/2023]
Abstract
Microalgae are gaining interest as food ingredient. Assessments of functional and nutritional properties are necessary to forward their implementation. In this study, protein content and composition of eight commercially available microalgae biomasses were determined and compared to conventional food proteins. A novel procedure for the determination of the true protein content was proposed: Multiplication of proteinic nitrogen with a sample-specific nitrogen-to-protein conversion factor kA. The proteinic nitrogen was derived from the difference of total nitrogen minus non-protein nitrogen. The average kA for microalgae was 5.3 and considerable variation between different microalgae biomasses were detected. In addition, the content of non-protein nitrogen varied between 3.4% and 15.4%. The amino acid profiles of Chlorella samples were nutritionally superior to the tested plant proteins but indicated lower protein interaction tendency, potentially limiting their structuring functionality. In contrast, Auxenochlorella contained lower amounts of indispensable amino acids while showing comparable interaction potential to plant proteins.
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Affiliation(s)
- Corina Sägesser
- Sustainable Food Processing Laboratory, Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Johanna M Kallfelz
- Sustainable Food Processing Laboratory, Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Samy Boulos
- Laboratory of Food Biochemistry, Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland.
| | - Laila Hammer
- Development and Analytics Research Division, Agroscope, Schwarzenburgstrasse 161, 3003 Bern, Switzerland; Department of Health, Swiss Distance University of Health (FFSH), Zollstrasse 11, 8005 Zürich, Switzerland; Division of Human Nutrition and Health, Wageningen University and Research, Stippeneng 4, 6708 Wageningen, Netherlands
| | - Lukas Böcker
- Sustainable Food Processing Laboratory, Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Reto Portmann
- Development and Analytics Research Division, Agroscope, Schwarzenburgstrasse 161, 3003 Bern, Switzerland
| | - Laura Nyström
- Laboratory of Food Biochemistry, Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Alexander Mathys
- Sustainable Food Processing Laboratory, Department of Health Sciences and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland.
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Syryamina VN, Wu X, Boulos S, Nyström L, Yulikov M. Pulse EPR spectroscopy and molecular modeling reveal the origins of the local heterogeneity of dietary fibers. Carbohydr Polym 2023; 319:121167. [PMID: 37567691 DOI: 10.1016/j.carbpol.2023.121167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/15/2023] [Accepted: 06/28/2023] [Indexed: 08/13/2023]
Abstract
Optimizing human diet by including dietary fibers would be more efficient when the fibers' chain interactions with other molecules are understood in depth. Thereby, it is important to develop methods for characterizing the fiber chain to be able to monitor its structural alterations upon intermolecular interactions. Here, we demonstrate the utility of the electron paramagnetic resonance (EPR) spectroscopy, complemented by simulations in probing the atomistic details of the chain conformations for spin-labeled fibers. Barley β-glucan, a native polysaccharide with linear chain, was utilized as a test fiber system to demonstrate the technique's capabilities. Pulse dipolar EPR data show good agreement with results of the fiber chain modeling, revealing sinuous chain conformations and providing polymer shape descriptors: the gyration tensor, spin-spin distance distribution function, and information about proton density near the spin probe. Results from EPR measurements point to the fiber aggregation in aqueous solution, which agrees with the results of the dynamic light scattering. We propose that the combination of pulse EPR measurements with modeling can be a perfect experimental tool for in-depth structural investigation of dietary fibers and their interaction under such conditions, and that the presented methodology can be extended to other weakly ordered or disordered macromolecules.
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Affiliation(s)
- Victoria N Syryamina
- Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland; Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russian Federation.
| | - Xiaowen Wu
- Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland.
| | - Samy Boulos
- Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland.
| | - Laura Nyström
- Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland.
| | - Maxim Yulikov
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg, 2, 8093 Zürich, Switzerland.
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3
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Wu X, Boulos S, Syryamina V, Nyström L, Yulikov M. Interaction of barley β-glucan with food dye molecules - An insight from pulse dipolar EPR spectroscopy. Carbohydr Polym 2023; 309:120698. [PMID: 36906364 DOI: 10.1016/j.carbpol.2023.120698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/25/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023]
Abstract
The interactions between dietary fibers (DFs) and small molecules are of great interest to food chemistry and nutrition science. However, the corresponding interaction mechanisms and structural rearrangements of DFs at the molecular level are still opaque due to the usually weak binding and the lack of appropriate techniques to determine details of conformational distributions in such weakly organized systems. By combining our previously established methodology on stochastic spin-labelling of DFs with the appropriately revised set of pulse electron paramagnetic resonance techniques, we present here a toolkit to determine the interactions between DFs and small molecules, using barley β-glucan as an example for neutral DF and a selection of food dye molecules as examples for small molecules. The proposed here methodology allowed us to observe subtle conformational changes of β-glucan by detecting multiple details of the local environment of the spin labels. Substantial variations of binding propensities were detected for different food dyes.
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Affiliation(s)
- Xiaowen Wu
- Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland.
| | - Samy Boulos
- Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland.
| | - Victoria Syryamina
- Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland; Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russia.
| | - Laura Nyström
- Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland.
| | - Maxim Yulikov
- Laboratory of Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Str. 10, 8093 Zürich, Switzerland.
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Yeo JL, Gulsin GS, Dattani A, Brady EM, Bilak JM, Ayton SL, Moss AJ, Pang W, Boulos S, House MJ, St Pierre TG, McCann GP. Association of hepatic steatosis with subclinical cardiac dysfunction in asymptomatic people with type 2 diabetes. Eur Heart J 2022. [DOI: 10.1093/eurheartj/ehac544.2406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Introduction
Non-alcoholic fatty liver disease is highly prevalent among people with type 2 diabetes (T2D) and is an emerging risk factor for heart failure with preserved ejection fraction (HFpEF). Whether excess liver adiposity is simply a marker of the coexisting adverse cardiometabolic risk profile or independently contributes to the development of HFpEF is unclear.
Purpose
To assess the association between liver fat fraction and subclinical cardiac dysfunction in adults with T2D.
Methods
Prospective cross-sectional study. Two-hundred and thirty-eight adults with T2D (mean age 63±7 years, 62% males, HbA1c 7.2±1.5%, diabetes duration 10±8 years) with no signs, symptoms, or evidence of cardiovascular disease and 40 age-, sex-, and ethnicity-matched non-diabetic controls (mean age 61±8 years, 63% males, HbA1c 5.2±1.2%) underwent comprehensive phenotyping with echocardiography and multiparametric cardiac MRI including adenosine stress and rest perfusion. Volumetric liver fat fraction (VLFF) was measured using a histologically validated, proprietary MRI technique blinded to all participant details. Inter-study reproducibility was assessed in participants (n=28) who underwent a repeat MRI within two weeks. Linear regression analysis was performed to assess any independent associations between VLFF and identified markers of subclinical cardiac dysfunction in subjects with T2D.
Results
People with T2D had evidence of concentric left ventricular (LV) remodelling (higher LV mass/volume), extracellular matrix expansion (higher ECV fraction), both systolic and diastolic dysfunction (lower global longitudinal systolic strain and E/A ratio, respectively), and coronary microvascular dysfunction (lower myocardial perfusion reserve) (Table 1). VLFF demonstrated excellent inter-study reproducibility with an intra-class correlation coefficient (ICC) of 0.988 (0.974–0.994). T2Ds had higher VLFF compared to controls [7.5 (3.8–13.7)% vs 2.9 (1.7–4.7)%, p<0.001]. In multivariable regression analysis adjusting for age, sex, ethnicity, body mass index, ambulatory systolic blood pressure, HbA1c, and low-density lipoprotein, VLFF (β=−0.161, p=0.027) was independently associated with E/A, but not other imaging measures of subclinical cardiac dysfunction.
Conclusion
Liver fat fraction is elevated in people with T2D and is independently associated with early LV diastolic dysfunction. These results add to the growing evidence that ectopic fat plays an important role in the pathogenesis of HFpEF and may be a potential target for intervention.
Funding Acknowledgement
Type of funding sources: Public Institution(s). Main funding source(s): National Institute for Health Research (NIHR) United Kingdom through a Research Professorship award (RP-2017-08-ST2-007).British Heart Foundation through a Clinical Research Training Fellowship (FS/16/47/32190).
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Affiliation(s)
- J L Yeo
- University of Leicester and the Leicester NIHR Biomedical Research Centre , Leicester , United Kingdom
| | - G S Gulsin
- University of Leicester and the Leicester NIHR Biomedical Research Centre , Leicester , United Kingdom
| | - A Dattani
- University of Leicester and the Leicester NIHR Biomedical Research Centre , Leicester , United Kingdom
| | - E M Brady
- University of Leicester and the Leicester NIHR Biomedical Research Centre , Leicester , United Kingdom
| | - J M Bilak
- University of Leicester and the Leicester NIHR Biomedical Research Centre , Leicester , United Kingdom
| | - S L Ayton
- University of Leicester and the Leicester NIHR Biomedical Research Centre , Leicester , United Kingdom
| | - A J Moss
- University of Leicester and the Leicester NIHR Biomedical Research Centre , Leicester , United Kingdom
| | - W Pang
- Resonance Health Ltd., Burswood , Western Australia , Australia
| | - S Boulos
- Resonance Health Ltd., Burswood , Western Australia , Australia
| | - M J House
- University of Western Australia, School of Physics , Perth , Australia
| | - T G St Pierre
- University of Western Australia, School of Physics , Perth , Australia
| | - G P McCann
- University of Leicester and the Leicester NIHR Biomedical Research Centre , Leicester , United Kingdom
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Marasca E, Zehnder-Wyss O, Boulos S, Nyström L. Estimation of Iron Availability in Modified Cereal β-Glucan Extracts by an in vitro Digestion Model. Front Nutr 2022; 9:879280. [PMID: 35769375 PMCID: PMC9234558 DOI: 10.3389/fnut.2022.879280] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 05/09/2022] [Indexed: 11/28/2022] Open
Abstract
For cereal-based foods rich in dietary fibers, iron bioavailability is known to be poor. For native cereal β-glucan extracts, literature has demonstrated that the main factor impacting the bioavailability is phytic acid, which is often found in association with dietary fibers. During food processing, β-glucan can undergo modifications which could potentially affect the equilibrium between phytic acid, fiber, and iron. In this study, an in vitro digestion was used to elucidate the iron dialysability, and hence estimate iron availability, in the presence of native, chelating resin (Chelex)-treated, oxidised, or partially hydrolysed oat and barley β-glucan extracts (at 1% actual β-glucan concentration), with or without phytase treatment. It was confirmed that pure, phytic acid-free β-glucan polysaccharide does not impede iron availability in cereal foods, while phytic acid, and to a smaller extent, also proteins, associated to β-glucan can do so. Neither Chelex-treatment nor partial hydrolysis, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) or NaIO4 oxidation significantly influenced the phytic acid content of the β-glucan extracts (ranging 2.0–3.9%; p > 0.05). Consequently, as long as intrinsic phytic acid was still present, the β-glucan extracts blocked the iron availability regardless of source (oat, barley) or Chelex-treatment, partial hydrolysis or NaIO4-oxidation down to 0–8% (relative to the reference without β-glucan extract). Remarkably, TEMPO-oxidation released around 50% of the sequestered iron despite unchanged phytic acid levels in the modified extract. We propose an iron-mobilising effect of the TEMPO product β-polyglucuronan from insoluble Fe(II)/phytate/protein aggregates to soluble Fe(II)/bile salt units that can cross the dialysis membrane. In addition, Chelex-treatment was identified as prerequisite for phytase to dramatically diminish iron retention of the extract for virtually full availability, with implications for optimal iron bioavailability in cereal foods.
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Lupo C, Boulos S, Gramm F, Wu X, Nyström L. A microcalorimetric and microscopic strategy to assess the interaction between neutral soluble dietary fibers and small molecules. Carbohydr Polym 2022; 287:119229. [DOI: 10.1016/j.carbpol.2022.119229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 11/02/2022]
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Demuth T, Boulos S, Nyström L. Structural investigation of oxidized arabinoxylan oligosaccharides by negative ionization HILIC-qToF-MS. Analyst 2021; 145:6691-6704. [PMID: 32812535 DOI: 10.1039/d0an01110j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Owing to the strong structure-function relationship of polysaccharides, the targeted modification of polysaccharides is attracting widespread interest in various fields, such as food industry, nutritional science, and biomedical research. Apart from intended functionalization, polysaccharide degradation mediated by hydroxyl radicals (HO˙) occurs in various industrial processes such as food processing. In particular, the oxidative degradation of feruloylated arabinoxylan (AX), a linearly-branched polysaccharide in cereals, causes chain scissions, and introduces new functional groups in the fiber, which can potentially modify the physicochemical properties and the functionalities of AX. However, the precise characterization of those structural modifications remains challenging due to the diversity of the oxidation products formed, the high molecular weight, and the relatively low quantity of newly formed functional groups. In this paper, selective (TEMPO-mediated) and random (Fenton) oxidations of several commercial xylo- and arabinoxylan oligosaccharides (A)XOS were studied as model systems by hydrophilic interaction UPLC-MS2 in negative ion resolution mode to identify potential oxidation products. An in-depth identification of acidic (A)XOS oxidation products derived from TEMPO-mediated oxidation provided novel insights in the selective functionalization of isomeric oligosaccharides. Furthermore, MS2 enabled the precise localisation of both glycosidic linkages and functional groups in oxidized (A)XOS. An innovative combination of an enzymatic sample preparation combined with a subsequent HILIC-MS2 analysis enabled the unprecedented comprehensive characterization of Fenton-induced oxidation products derived from AX. In future, this holistic analytical approach will enable the characterization of both selective and non-selective AX oxidation procedures in various applications.
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Affiliation(s)
- Teresa Demuth
- ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 9, 8092 Zurich, Switzerland.
| | - Samy Boulos
- ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 9, 8092 Zurich, Switzerland.
| | - Laura Nyström
- ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 9, 8092 Zurich, Switzerland.
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Eder S, Zueblin P, Diener M, Peydayesh M, Boulos S, Mezzenga R, Nyström L. Effect of Polysaccharide Conformation on Ultrafiltration Separation Performance. Carbohydr Polym 2021; 260:117830. [PMID: 33712169 DOI: 10.1016/j.carbpol.2021.117830] [Citation(s) in RCA: 7] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/12/2021] [Accepted: 02/13/2021] [Indexed: 11/18/2022]
Abstract
The manifold array of saccharide linkages leads to a great variety of polysaccharide architectures, comprising three conformations in aqueous solution: compact sphere, random coil, and rigid rod. This conformational variation limits the suitability of the commonly applied molecular weight cut-off (MWCO) as selection criteria for polysaccharide ultrafiltration membranes, as it is based on globular marker proteins with narrow Mw and hydrodynamic volume relation. Here we show the effect of conformation on ultrafiltration performance using randomly coiled pullulan and rigid rod-like scleroglucan as model polysaccharides for membrane rejection and molecular weight distribution. Ultrafiltration with a 10 kDa polyethersulfone membrane yielded significant different recoveries for pullulan and scleroglucan showing 1% and 71%, respectively. We found deviations greater than 77-fold between nominal MWCO and apparent Mw of pullulan and scleroglucan, while recovering over 90% polysaccharide with unchanged Mw. We anticipate our work as starting point towards an optimized membrane selection for polysaccharide applications.
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Affiliation(s)
- Severin Eder
- ETH Zurich, Department of Health Science and Technology, Institute of Food, Nutrition and Health, Laboratory of Food Biochemistry, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Patrick Zueblin
- ETH Zurich, Department of Health Science and Technology, Institute of Food, Nutrition and Health, Laboratory of Food Biochemistry, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Michael Diener
- ETH Zurich, Department of Health Science and Technology, Institute of Food, Nutrition and Health, Laboratory of Food and Soft Materials, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Mohammad Peydayesh
- ETH Zurich, Department of Health Science and Technology, Institute of Food, Nutrition and Health, Laboratory of Food and Soft Materials, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Samy Boulos
- ETH Zurich, Department of Health Science and Technology, Institute of Food, Nutrition and Health, Laboratory of Food Biochemistry, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Raffaele Mezzenga
- ETH Zurich, Department of Health Science and Technology, Institute of Food, Nutrition and Health, Laboratory of Food and Soft Materials, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Laura Nyström
- ETH Zurich, Department of Health Science and Technology, Institute of Food, Nutrition and Health, Laboratory of Food Biochemistry, Schmelzbergstrasse 9, 8092 Zurich, Switzerland.
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Shen Y, Kalograiaki I, Prunotto A, Dunne M, Boulos S, Taylor NMI, Sumrall ET, Eugster MR, Martin R, Julian-Rodero A, Gerber B, Leiman PG, Menéndez M, Peraro MD, Cañada FJ, Loessner MJ. Structural basis for recognition of bacterial cell wall teichoic acid by pseudo-symmetric SH3b-like repeats of a viral peptidoglycan hydrolase. Chem Sci 2020; 12:576-589. [PMID: 34163788 PMCID: PMC8179006 DOI: 10.1039/d0sc04394j] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [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: 12/24/2022] Open
Abstract
Endolysins are bacteriophage-encoded peptidoglycan hydrolases targeting the cell wall of host bacteria via their cell wall-binding domains (CBDs). The molecular basis for selective recognition of surface carbohydrate ligands by CBDs remains elusive. Here, we describe, in atomic detail, the interaction between the Listeria phage endolysin domain CBD500 and its cell wall teichoic acid (WTA) ligands. We show that 3′O-acetylated GlcNAc residues integrated into the WTA polymer chain are the key epitope recognized by a CBD binding cavity located at the interface of tandem copies of beta-barrel, pseudo-symmetric SH3b-like repeats. This cavity consists of multiple aromatic residues making extensive interactions with two GlcNAc acetyl groups via hydrogen bonds and van der Waals contacts, while permitting the docking of the diastereomorphic ligands. Our multidisciplinary approach tackled an extremely challenging protein–glycopolymer complex and delineated a previously unknown recognition mechanism by which a phage endolysin specifically recognizes and targets WTA, suggesting an adaptable model for regulation of endolysin specificity. Combining genetic, biochemical and computational approaches, we elucidated the molecular mechanisms underlying the recognition of Listeria wall teichoic acid by bacteriophage-encoded SH3b repeats.![]()
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Affiliation(s)
- Yang Shen
- Institute of Food, Nutrition and Health, ETH Zurich Schmelzbergstrasse 7 8092 Zurich Switzerland
| | - Ioanna Kalograiaki
- Centro de Investigaciones Biológicas, Margarita Salas, Consejo Superior de Investigaciones Científicas Ramiro de Maeztu 9 28040 Madrid Spain.,Centro de Investigación Biomédica en Red-Enfermedades Respiratorias (CIBERES) Avenida de Monforte de Lemos 3-5 28029 Madrid Spain
| | - Alessio Prunotto
- Laboratory for Biomolecular Modeling, EPFL IBI-SV Station 19 1015 Lausanne Switzerland
| | - Matthew Dunne
- Institute of Food, Nutrition and Health, ETH Zurich Schmelzbergstrasse 7 8092 Zurich Switzerland
| | - Samy Boulos
- Institute of Food, Nutrition and Health, ETH Zurich Schmelzbergstrasse 9 8092 Zurich Switzerland
| | - Nicholas M I Taylor
- Structural Biology of Molecular Machines Group, Protein Structure & Function Programme, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen Blegdamsvej 3B Copenhagen 2200 Denmark
| | - Eric T Sumrall
- Institute of Food, Nutrition and Health, ETH Zurich Schmelzbergstrasse 7 8092 Zurich Switzerland
| | - Marcel R Eugster
- Institute of Food, Nutrition and Health, ETH Zurich Schmelzbergstrasse 7 8092 Zurich Switzerland
| | - Rebecca Martin
- Institute of Food, Nutrition and Health, ETH Zurich Schmelzbergstrasse 7 8092 Zurich Switzerland
| | - Alicia Julian-Rodero
- Institute of Food, Nutrition and Health, ETH Zurich Schmelzbergstrasse 7 8092 Zurich Switzerland
| | - Benjamin Gerber
- Institute of Food, Nutrition and Health, ETH Zurich Schmelzbergstrasse 7 8092 Zurich Switzerland
| | - Petr G Leiman
- University of Texas Medical Branch, Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics 301 University Blvd Galveston TX 77555-0647 USA
| | - Margarita Menéndez
- Centro de Investigación Biomédica en Red-Enfermedades Respiratorias (CIBERES) Avenida de Monforte de Lemos 3-5 28029 Madrid Spain.,Instituto de Química-Física Rocasolano, Consejo Superior de Investigaciones Cientificas Serrano 119 28006 Madrid Spain
| | - Matteo Dal Peraro
- Laboratory for Biomolecular Modeling, EPFL IBI-SV Station 19 1015 Lausanne Switzerland
| | - Francisco Javier Cañada
- Centro de Investigaciones Biológicas, Margarita Salas, Consejo Superior de Investigaciones Científicas Ramiro de Maeztu 9 28040 Madrid Spain.,Centro de Investigación Biomédica en Red-Enfermedades Respiratorias (CIBERES) Avenida de Monforte de Lemos 3-5 28029 Madrid Spain
| | - Martin J Loessner
- Institute of Food, Nutrition and Health, ETH Zurich Schmelzbergstrasse 7 8092 Zurich Switzerland
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10
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Boulos S, Tännler A, Nyström L. Nitrogen-to-Protein Conversion Factors for Edible Insects on the Swiss Market: T. molitor, A. domesticus, and L. migratoria. Front Nutr 2020; 7:89. [PMID: 32754611 PMCID: PMC7366252 DOI: 10.3389/fnut.2020.00089] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 05/15/2020] [Indexed: 11/23/2022] Open
Abstract
With an increasing worldwide demand for animal protein, insects are becoming a promising sustainable option for meat protein replacement. However, reported protein contents of insects are often overestimated when calculated as "crude protein" = 6.25 × nitrogen content (N), compared to true protein contents quantified from the sum of amino acid (AA) residues. In this study, the main two types of usual nitrogen-to-protein conversion factors k p and k A were determined on the basis of true protein/total nitrogen and true protein/protein nitrogen, respectively, with focus on the three insect species legally sold on the Swiss food market. T. molitor (mealworm larvae), A. domesticus (house crickets), and L. migratoria (locusts) from various breeders were analyzed for total and amide nitrogen, chitin, and AA composition. Careful control experiments of insect samples spiked with a protein standard were conducted to establish the recovery of true protein, which was with >95% excellent. Mealworms, crickets, and locusts exhibited similar AA-profiles and true protein contents of 51, 55, and 47 g/100 g (dry weight basis), respectively. Specific conversion factors k p showed little variability between the three insect species with 5.41, 5.25, and 5.33 for mealworms, crickets, and locusts, respectively, and confirmed an average ~17% overestimation of protein contents when using 6.25 × N. The determined average k p of 5.33 is supported by extracted literature data and is suggested for general use instead of 6.25 × N to calculate more accurate insect protein contents, whereas the average pure protein conversion factor k A of 5.6 is proposed for use in the case of insect protein isolates.
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Affiliation(s)
| | | | - Laura Nyström
- Laboratory of Food Biochemistry, Department of Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, Zürich, Switzerland
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11
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Lupo C, Boulos S, Nyström L. Influence of Partial Acid Hydrolysis on Size, Dispersity, Monosaccharide Composition, and Conformation of Linearly-Branched Water-Soluble Polysaccharides. Molecules 2020; 25:E2982. [PMID: 32610625 PMCID: PMC7412010 DOI: 10.3390/molecules25132982] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/21/2020] [Accepted: 06/24/2020] [Indexed: 11/26/2022] Open
Abstract
The effect of partial acid hydrolysis on the physical and chemical properties of galactomannan, arabinoxylan, and xyloglucan was investigated. Polysaccharides were treated at 50 °C with hydrochloric acid for 3-48 h. Portions of isopropanol (i-PrOH) were added sequentially to the hydrolyzates, resulting in fractions that were collected by centrifugation. As expected, a significant reduction of weight-average molecular weight (Mw) was observed with increasing hydrolysis time. Fractional precipitation was successfully applied to collect at least one polymer fraction with dispersity (Đ) close to one for each polysaccharide. The monosaccharide composition analysis showed that the partial hydrolysis usually lowered the relative amount of side chains, with the exception of galactomannan, where the composition remained largely unaffected. Estimation of the polymer conformation in solution, through evaluation of the Mark-Houwink parameter coefficient (α), confirmed that acid hydrolysis influenced the polysaccharides' conformation. It was demonstrated that acid treatment in dilute solution followed by fractional isopropanol precipitation is a method, extendible to a variety of polysaccharides, to obtain materials of decreased molecular weight and low dispersity with slightly altered overall composition and conformation.
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Affiliation(s)
| | | | - Laura Nyström
- Department of Health Science and Technology, Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland; (C.L.); (S.B.)
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12
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Sumrall ET, Schefer CRE, Rismondo J, Schneider SR, Boulos S, Gründling A, Loessner MJ, Shen Y. Galactosylated wall teichoic acid, but not lipoteichoic acid, retains InlB on the surface of serovar 4b Listeria monocytogenes. Mol Microbiol 2020; 113:638-649. [PMID: 32185836 PMCID: PMC7155027 DOI: 10.1111/mmi.14455] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/20/2019] [Accepted: 01/09/2020] [Indexed: 11/20/2022]
Abstract
Listeria monocytogenes is a Gram-positive, intracellular pathogen harboring the surface-associated virulence factor InlB, which enables entry into certain host cells. Structurally diverse wall teichoic acids (WTAs), which can also be differentially glycosylated, determine the antigenic basis of the various Listeria serovars. WTAs have many physiological functions; they can serve as receptors for bacteriophages, and provide a substrate for binding of surface proteins such as InlB. In contrast, the membrane-anchored lipoteichoic acids (LTAs) do not show significant variation and do not contribute to serovar determination. It was previously demonstrated that surface-associated InlB non-covalently adheres to both WTA and LTA, mediating its retention on the cell wall. Here, we demonstrate that in a highly virulent serovar 4b strain, two genes gtlB and gttB are responsible for galactosylation of LTA and WTA respectively. We evaluated the InlB surface retention in mutants lacking each of these two genes, and found that only galactosylated WTA is required for InlB surface presentation and function, cellular invasiveness and phage adsorption, while galactosylated LTA plays no role thereof. Our findings demonstrate that a simple pathogen-defining serovar antigen, that mediates bacteriophage susceptibility, is necessary and sufficient to sustain the function of an important virulence factor.
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Affiliation(s)
- Eric T Sumrall
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | | | - Jeanine Rismondo
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | | | - Samy Boulos
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Angelika Gründling
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Martin J Loessner
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Yang Shen
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
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13
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Peydayesh M, Suter MK, Bolisetty S, Boulos S, Handschin S, Nyström L, Mezzenga R. Amyloid Fibrils Aerogel for Sustainable Removal of Organic Contaminants from Water. Adv Mater 2020; 32:e1907932. [PMID: 32026524 DOI: 10.1002/adma.201907932] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/16/2020] [Indexed: 05/21/2023]
Abstract
Water contamination by organic pollutants is ubiquitous and hence a global concern due to detrimental effects on the environment and human health. Here, it is demonstrated that amyloid fibrils aerogels are ideal adsorbers for removing organic pollutants from water. To this end, amyloid fibrils prepared from β-lactoglobulin, the major constituent of milk whey protein, are used as building blocks for the fabrication of the aerogels. The adsorption of Bentazone, Bisphenol A, and Ibuprofen, as model pollutants, is evaluated under quasi-static conditions, without use of energy or pressure. Through adsorption by amyloid fibrils aerogel, excellent removal efficiencies of 92%, 78%, and 98% are demonstrated for Bentazone, Bisphenol A, and Ibuprofen, respectively. Furthermore, the maximum adsorption capacity of amyloid fibrils aerogel for Bentazone, Bisphenol A, and Ibuprofen is 54.2, 50.6, and 69.6 mg g-1 , respectively. To shed light on the adsorption equilibrium process, adsorption isotherms, binding constants, saturation limits, and the effect of pH are evaluated. Finally, the regeneration of the aerogel over three consecutive cycles is studied, exhibiting high reusability with no significant changes in its removal performance. These results point at amyloid fibrils aerogels as a sustainable, efficient, and inexpensive technology for alleviating the ubiquitous water contamination by organic pollutants.
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Affiliation(s)
- Mohammad Peydayesh
- ETH Zurich, Department of Health Sciences and Technology, 8092, Zurich, Switzerland
| | - Meret Kim Suter
- ETH Zurich, Department of Health Sciences and Technology, 8092, Zurich, Switzerland
| | - Sreenath Bolisetty
- ETH Zurich, Department of Health Sciences and Technology, 8092, Zurich, Switzerland
- BluAct Technologies GmbH, 8092, Zurich, Switzerland
| | - Samy Boulos
- Laboratory of Food Biochemistry, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zurich, 8092, Zurich, Switzerland
| | - Stephan Handschin
- ETH Zurich, Department of Health Sciences and Technology, 8092, Zurich, Switzerland
| | - Laura Nyström
- Laboratory of Food Biochemistry, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zurich, 8092, Zurich, Switzerland
| | - Raffaele Mezzenga
- ETH Zurich, Department of Health Sciences and Technology, 8092, Zurich, Switzerland
- Department of Materials, ETH Zurich, 8093, Zurich, Switzerland
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14
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Marasca E, Boulos S, Nyström L. Bile acid-retention by native and modified oat and barley β-glucan. Carbohydr Polym 2020; 236:116034. [PMID: 32172850 DOI: 10.1016/j.carbpol.2020.116034] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [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: 08/29/2019] [Revised: 01/15/2020] [Accepted: 02/17/2020] [Indexed: 10/25/2022]
Abstract
Foods rich in cereal β-glucan are efficient dietary tools to help reduce serum cholesterol levels and hence the risk of cardiovascular diseases. However, β-glucan undergoes various reactions during food processing, which alter its viscous properties and interactions with components of the gastrointestinal tract. It has been proposed in the literature that oxidation and partial hydrolysis increase β-glucan's bile acid-binding activity, and therefore its effectiveness in lowering cholesterol. Here, the passage kinetics of a bile salt mix across a dialysis membrane was studied with or without oat and barley β-glucan extracts, native or modified (partial hydrolysis and oxidations by sodium periodate or TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl)). Bile acid-retention turned out to be purely a function of viscosity, with the most viscous native extracts exhibiting the strongest retardation of bile acid permeation. Opposite of what was suggested in the literature, oxidation and molecular weight reduction do not seem to increase the bile acid-binding capability of β-glucan.
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Affiliation(s)
- Elena Marasca
- Institute of Food, Nutrition and Health, ETH Zurich, 8092, Zurich, Switzerland
| | - Samy Boulos
- Institute of Food, Nutrition and Health, ETH Zurich, 8092, Zurich, Switzerland
| | - Laura Nyström
- Institute of Food, Nutrition and Health, ETH Zurich, 8092, Zurich, Switzerland.
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15
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Gold M, Cassar CM, Zurbrügg C, Kreuzer M, Boulos S, Diener S, Mathys A. Biowaste treatment with black soldier fly larvae: Increasing performance through the formulation of biowastes based on protein and carbohydrates. Waste Manag 2020; 102:319-329. [PMID: 31707321 DOI: 10.1016/j.wasman.2019.10.036] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 10/18/2019] [Accepted: 10/20/2019] [Indexed: 05/12/2023]
Abstract
A key challenge for black soldier fly larvae (BSFL) treatment is its variable reliability and efficiency when applied to different biowastes. Similar to other biowaste treatment technologies, co-conversion could compensate for variability in the composition of biowastes. Using detailed nutrient analyses, this study assessed whether mixing biowastes to similar protein and non-fibre carbohydrate (NFC) contents increased the performance and reduced the variability of BSFL treatment in comparison to the treatment of individual wastes. The biowastes examined were mill by-products, human faeces, poultry slaughterhouse waste, cow manure, and canteen waste. Biowaste formulations had a protein-to-NFC ratio of 1:1, a protein content of 14-19%, and a NFC content of 13-15% (dry mass). Performance parameters that were assessed included survival and bioconversion rate, waste reduction, and waste conversion and protein conversion efficiency. In comparison to poultry feed (benchmark), vegetable canteen waste showed the best performance and cow manure performed worst. Formulations showed significantly improved performance and lower variability in comparison to the individual wastes. However, variability in performance was higher than expected for the formulations. One reason for this variability could be different fibre and lipid contents, which correlated with the performance results of the formulations. Overall, this research provides baseline knowledge and guidance on how BSFL treatment facilities may systematically operate using biowastes of varying types and compositions.
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Affiliation(s)
- Moritz Gold
- ETH Zurich: Swiss Federal Institute of Technology Zurich, Institute of Food, Nutrition and Health, Laboratory of Sustainable Food Processing, Schmelzbergstrasse 9, 8092 Zurich, Switzerland; Eawag: Swiss Federal Institute of Aquatic Science and Technology, Sandec: Department Sanitation, Water and Solid Water for Development, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Cecille Marie Cassar
- ETH Zurich: Swiss Federal Institute of Technology Zurich, Institute of Food, Nutrition and Health, Laboratory of Sustainable Food Processing, Schmelzbergstrasse 9, 8092 Zurich, Switzerland; Eawag: Swiss Federal Institute of Aquatic Science and Technology, Sandec: Department Sanitation, Water and Solid Water for Development, Überlandstrasse 133, 8600 Dübendorf, Switzerland; University of Stuttgart: Institute for Sanitary Engineering, Water Quality and Solid Waste Management, Chair of Waste Management and Emissions, Bandtäle 2, 70569 Stuttgart, Germany
| | - Christian Zurbrügg
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, Sandec: Department Sanitation, Water and Solid Water for Development, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Michael Kreuzer
- ETH Zurich: Swiss Federal Institute of Technology Zurich, Institute of Agricultural Sciences, Animal Nutrition, Universitätstrasse 2, 8092 Zurich, Switzerland
| | - Samy Boulos
- ETH Zurich: Swiss Federal Institute of Technology Zurich, Institute of Food, Nutrition and Health, Laboratory of Food Biochemistry, Schmelzbergstrasse 9, 8092 Zurich, Switzerland
| | - Stefan Diener
- Biovision Foundation, Heinrichstrasse 147, 8005 Zurich, Switzerland
| | - Alexander Mathys
- ETH Zurich: Swiss Federal Institute of Technology Zurich, Institute of Food, Nutrition and Health, Laboratory of Sustainable Food Processing, Schmelzbergstrasse 9, 8092 Zurich, Switzerland.
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16
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Sumrall ET, Shen Y, Keller AP, Rismondo J, Pavlou M, Eugster MR, Boulos S, Disson O, Thouvenot P, Kilcher S, Wollscheid B, Cabanes D, Lecuit M, Gründling A, Loessner MJ. Phage resistance at the cost of virulence: Listeria monocytogenes serovar 4b requires galactosylated teichoic acids for InlB-mediated invasion. PLoS Pathog 2019; 15:e1008032. [PMID: 31589660 PMCID: PMC6779246 DOI: 10.1371/journal.ppat.1008032] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [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: 04/08/2019] [Accepted: 08/15/2019] [Indexed: 01/13/2023] Open
Abstract
The intracellular pathogen Listeria monocytogenes is distinguished by its ability to invade and replicate within mammalian cells. Remarkably, of the 15 serovars within the genus, strains belonging to serovar 4b cause the majority of listeriosis clinical cases and outbreaks. The Listeria O-antigens are defined by subtle structural differences amongst the peptidoglycan-associated wall-teichoic acids (WTAs), and their specific glycosylation patterns. Here, we outline the genetic determinants required for WTA decoration in serovar 4b L. monocytogenes, and demonstrate the exact nature of the 4b-specific antigen. We show that challenge by bacteriophages selects for surviving clones that feature mutations in genes involved in teichoic acid glycosylation, leading to a loss of galactose from both wall teichoic acid and lipoteichoic acid molecules, and a switch from serovar 4b to 4d. Surprisingly, loss of this galactose decoration not only prevents phage adsorption, but leads to a complete loss of surface-associated Internalin B (InlB),the inability to form actin tails, and a virulence attenuation in vivo. We show that InlB specifically recognizes and attaches to galactosylated teichoic acid polymers, and is secreted upon loss of this modification, leading to a drastically reduced cellular invasiveness. Consequently, these phage-insensitive bacteria are unable to interact with cMet and gC1q-R host cell receptors, which normally trigger cellular uptake upon interaction with InlB. Collectively, we provide detailed mechanistic insight into the dual role of a surface antigen crucial for both phage adsorption and cellular invasiveness, demonstrating a trade-off between phage resistance and virulence in this opportunistic pathogen. L. monocytogenes is a Gram-positive, food-borne, intracellular pathogen that causes severe infection in susceptible individuals. Interestingly, almost all infections are caused by a subset of strains belonging to certain serovars featuring a complex glycosylation pattern on their cell surface. Using an engineered bacteriophage that specifically recognizes these modifications we selected for mutants that lost these sugars. We found that the resulting strains are severely deficient in invading host cells as we observed that a major virulence factor mediating host cell entry requires galactose decoration of the cell surface for its function. Without this galactose decoration, the strain represents a serovar not associated with disease. Altogether, we show a complex interplay between bacteriophages, bacteria, and the host, demonstrating that cellular invasiveness is dependent upon a serovar-defining structure, which also serves as a phage receptor.
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Affiliation(s)
- Eric T. Sumrall
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Yang Shen
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
- * E-mail: (YS); (MJL)
| | - Anja P. Keller
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Jeanine Rismondo
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Maria Pavlou
- Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
| | - Marcel R. Eugster
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Samy Boulos
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Olivier Disson
- Biology of Infection Unit, Institut Pasteur, Paris, France
- Inserm U1117, Paris, France
| | - Pierre Thouvenot
- Biology of Infection Unit, Institut Pasteur, Paris, France
- Inserm U1117, Paris, France
| | - Samuel Kilcher
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Bernd Wollscheid
- Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
| | - Didier Cabanes
- i3S - Instituto de Investigação e Inovação em Saúde; Institute for Molecular and Cell Biology, University of Porto, Porto, Portugal
| | - Marc Lecuit
- Biology of Infection Unit, Institut Pasteur, Paris, France
- Inserm U1117, Paris, France
- Paris Descartes University, Department of Infectious Diseases and Tropical Medicine, Necker-Enfants Malades University Hospital, APHP, Institut Imagine, Paris, France
| | - Angelika Gründling
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Martin J. Loessner
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
- * E-mail: (YS); (MJL)
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17
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Münger LH, Boulos S, Nyström L. UPLC-MS/MS Based Identification of Dietary Steryl Glucosides by Investigation of Corresponding Free Sterols. Front Chem 2018; 6:342. [PMID: 30186828 PMCID: PMC6113793 DOI: 10.3389/fchem.2018.00342] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 07/19/2018] [Indexed: 11/17/2022] Open
Abstract
Dietary plant foods are characterized by a vast molecular diversity of glycosylated sterols (SG) that differ in the structure of the steryl backbone. The identification of these polar steryl conjugates represents a major challenge as they are structurally highly similar, and commercial standards are limited to a few naturally abundant species. Spectral databases do not yet contain MS/MS spectra of these sterol conjugates obtained by electrospray ionization (ESI), which would facilitate their reliable identification. Thus, this study aimed at providing novel information on ESI-MS/MS spectra of both abundant and minor SG found in foods. As a first step, however, free sterols (FS) were investigated for their fragmentation behavior as they share the same intermediate ion as SG. Pure SG were obtained from commercially available standard mixtures and minor SG were extracted from different food sources (oat bran, wheat bran, pumpkin seeds, melon, rapeseeds, and potato peel). ESI-MS/MS spectra of 15 FS were assessed and fragment ions reflective of structural features were identified and rationalized. Subsequently, 14 SG were identified at four different levels, while relative retention times from chromatographic separation and spectral features of FS served to identify five SG. Spectral data from FS were directly transferable to SG when analyzed as aglycone ions as shown by similarity scores while SG were characterized by shorter retention times in reverse phase chromatography and the additional analysis as sodiated adduct confirmed their glycosidic nature. Moreover, we report for the first time the occurrence of 24-methylenecholesterol and a 4-monomethyl sterol as glycosidic conjugates in higher plants. The presented data will serve as a valuable tool for SG profiling of foods by facilitating their identification.
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Affiliation(s)
- Linda H Münger
- Laboratory of Food Biochemistry, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Zurich, Switzerland
| | - Samy Boulos
- Laboratory of Food Biochemistry, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Zurich, Switzerland
| | - Laura Nyström
- Laboratory of Food Biochemistry, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Zurich, Switzerland
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18
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Boulos S, Nyström L. Complementary Sample Preparation Strategies for Analysis of Cereal β-Glucan Oxidation Products by UPLC-MS/MS. Front Chem 2017; 5:90. [PMID: 29164106 PMCID: PMC5673685 DOI: 10.3389/fchem.2017.00090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/17/2017] [Indexed: 11/18/2022] Open
Abstract
The oxidation of cereal (1→3,1→4)-β-D-glucan can influence the health promoting and technological properties of this linear, soluble homopolysaccharide by introduction of new functional groups or chain scission. Apart from deliberate oxidative modifications, oxidation of β-glucan can already occur during processing and storage, which is mediated by hydroxyl radicals (HO•) formed by the Fenton reaction. We present four complementary sample preparation strategies to investigate oat and barley β-glucan oxidation products by hydrophilic interaction ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), employing selective enzymatic digestion, graphitized carbon solid phase extraction (SPE), and functional group labeling techniques. The combination of these methods allows for detection of both lytic (C1, C3/4, C5) and non-lytic (C2, C4/3, C6) oxidation products resulting from HO•-attack at different glucose-carbons. By treating oxidized β-glucan with lichenase and β-glucosidase, only oxidized parts of the polymer remained in oligomeric form, which could be separated by SPE from the vast majority of non-oxidized glucose units. This allowed for the detection of oligomers with mid-chain glucuronic acids (C6) and carbonyls, as well as carbonyls at the non-reducing end from lytic C3/C4 oxidation. Neutral reducing ends were detected by reductive amination with anthranilic acid/amide as labeled glucose and cross-ring cleaved units (arabinose, erythrose) after enzyme treatment and SPE. New acidic chain termini were observed by carbodiimide-mediated amidation of carboxylic acids as anilides of gluconic, arabinonic, and erythronic acids. Hence, a full characterization of all types of oxidation products was possible by combining complementary sample preparation strategies. Differences in fine structure depending on source (oat vs. barley) translates to the ratio of observed oxidized oligomers, with in-depth analysis corroborating a random HO•-attack on glucose units irrespective of glycosidic linkage and neighborhood. The method was demonstrated to be (1) sufficiently sensitive to allow for the analysis of oxidation products also from a mild ascorbate-driven Fenton reaction, and (2) to be specific for cereal β-glucan even in the presence of other co-oxidized polysaccharides. This opens doors to applications in food processing to assess potential oxidations and provides the detailed structural basis to understand the effect oxidized functional groups have on β-glucan's health promoting and technological properties.
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Affiliation(s)
| | - Laura Nyström
- Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
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19
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Shen Y, Boulos S, Sumrall E, Gerber B, Julian-Rodero A, Eugster MR, Fieseler L, Nyström L, Ebert MO, Loessner MJ. Structural and functional diversity in Listeria cell wall teichoic acids. J Biol Chem 2017; 292:17832-17844. [PMID: 28912268 DOI: 10.1074/jbc.m117.813964] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [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: 08/22/2017] [Indexed: 11/06/2022] Open
Abstract
Wall teichoic acids (WTAs) are the most abundant glycopolymers found on the cell wall of many Gram-positive bacteria, whose diverse surface structures play key roles in multiple biological processes. Despite recent technological advances in glycan analysis, structural elucidation of WTAs remains challenging due to their complex nature. Here, we employed a combination of ultra-performance liquid chromatography-coupled electrospray ionization tandem-MS/MS and NMR to determine the structural complexity of WTAs from Listeria species. We unveiled more than 10 different types of WTA polymers that vary in their linkage and repeating units. Disparity in GlcNAc to ribitol connectivity, as well as variable O-acetylation and glycosylation of GlcNAc contribute to the structural diversity of WTAs. Notably, SPR analysis indicated that constitution of WTA determines the recognition by bacteriophage endolysins. Collectively, these findings provide detailed insight into Listeria cell wall-associated carbohydrates, and will guide further studies on the structure-function relationship of WTAs.
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Affiliation(s)
- Yang Shen
- From the Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, CH-8092 Zurich,
| | - Samy Boulos
- the Laboratory of Food Biochemistry, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 9, CH-8092 Zurich
| | - Eric Sumrall
- From the Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, CH-8092 Zurich
| | - Benjamin Gerber
- From the Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, CH-8092 Zurich
| | - Alicia Julian-Rodero
- From the Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, CH-8092 Zurich
| | - Marcel R Eugster
- From the Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, CH-8092 Zurich
| | - Lars Fieseler
- the ZHAW School of Life Sciences and Facility Management, Einsiedlerstrasse 31, CH-8820 Wädenswil, and
| | - Laura Nyström
- the Laboratory of Food Biochemistry, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 9, CH-8092 Zurich
| | - Marc-Olivier Ebert
- the Laboratory of Organic Chemistry, ETH Zurich, Vladmimir-Prelog-Weg 3, CH-8093 Zurich, Switzerland
| | - Martin J Loessner
- From the Laboratory of Food Microbiology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, CH-8092 Zurich
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20
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Abstract
Fenton-induced degradation of isomeric β-d-glucotetraoses is systematically investigated by negative mode HILIC UPLC-MS/MS with regard to the effect of the glycosidic linkage on kinetics, product profiles, and MS/MS fragmentation patterns.
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Affiliation(s)
- Samy Boulos
- ETH Zurich
- Institute of Food
- Nutrition and Health
- 8092 Zurich
- Switzerland
| | - Laura Nyström
- ETH Zurich
- Institute of Food
- Nutrition and Health
- 8092 Zurich
- Switzerland
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21
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Anderton RS, Price LL, Turner BJ, Meloni BP, Mitrpant C, Mastaglia FL, Goh C, Wilton SD, Boulos S. Co-regulation of survival of motor neuron and Bcl-xL expression: implications for neuroprotection in spinal muscular atrophy. Neuroscience 2012; 220:228-36. [PMID: 22732506 DOI: 10.1016/j.neuroscience.2012.06.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Revised: 06/15/2012] [Accepted: 06/18/2012] [Indexed: 11/29/2022]
Abstract
Spinal muscular atrophy (SMA), a fatal genetic motor disorder of infants, is caused by diminished full-length survival of motor neuron (SMN) protein levels. Normally involved in small nuclear ribonucleoprotein (snRNP) assembly and pre-mRNA splicing, recent studies suggest that SMN plays a critical role in regulating apoptosis. Interestingly, the anti-apoptotic Bcl-x isoform, Bcl-xL, is reduced in SMA. In a related finding, Sam68, an RNA-binding protein, was found to modulate splicing of SMN and Bcl-xL transcripts, promoting SMNΔ7 and pro-apoptotic Bcl-xS transcripts. Here we demonstrate that Bcl-xL expression increases SMN protein by ∼2-fold in SH-SY5Y cells. Conversely, SMN expression increases Bcl-xL protein levels by ∼6-fold in SH-SY5Y cells, and ∼2.5-fold in the brains of transgenic mice over-expressing SMN (PrP-SMN). Moreover, Sam68 protein levels were markedly reduced following SMN and Bcl-xL expression in SH-SY5Y cells, suggesting a feedback mechanism co-regulating levels of both proteins. We also found that exogenous SMN expression increased full-length SMN transcripts, possibly by promoting exon 7 inclusion. Finally, co-expression of SMN and Bcl-xL produced an additive anti-apoptotic effect following PI3-kinase inhibition in SH-SY5Y cells. Our findings implicate Bcl-xL as another potential target in SMA therapeutics, and indicate that therapeutic increases in SMN may arise from modest increases in total SMN.
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Affiliation(s)
- R S Anderton
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Australian Neuromuscular Research Institute, Western Australia, Australia.
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Ammoun S, Zhou L, Barczyk M, Hilton D, Hafizi S, Hanemann C, Lehnus KS, Donovan LK, Pilkington GJ, An Q, Anderson IA, Thomson S, Bailey M, Lekka E, Law J, Davis C, Banfill K, Loughrey C, Hatfield P, Bax D, Elliott R, Bishop R, Taylor K, Marshall L, Gaspar N, Viana-Pereira M, Reis R, Renshaw J, Ashworth A, Lord C, Jones C, Bellamy C, Shaw L, Alder J, Shorrocks A, Lea R, Birks S, Burnet M, Pilkington G, Bruch JD, Ho J, Watts C, Price SJ, Camp S, Apostolopoulos V, Mehta A, Roncaroli F, Nandi D, Clark B, Mackinnon M, MacLeod N, Stewart W, Chalmers A, Cole A, Hanna G, Bailie K, Conkey D, Harney J, Darlow C, Chapman S, Mohsen L, Price S, Donovan L, Birks S, Pilkington G, Dyer H, Lord H, Fletcher K, das Nair R, MacNiven J, Basu S, Byrne P, Glancz L, Critchley G, Grech-Sollars M, Saunders D, Phipps K, Clayden J, Clark C, Greco A, Acquati S, Marino S, Hammouche S, Wilkins SP, Smith T, Brodbelt A, Hammouche S, Clark S, Wong AHL, Eldridge P, Farah JO, Ho J, Bruch J, Watts C, Price S, Lamb G, Smith S, James A, Glegg M, Jeffcote T, Boulos S, Robbins P, Knuckey N, Banigo A, Brodbelt AR, Jenkinson MD, Jeyapalan JN, Mumin MA, Forshew T, Lawson AR, Tatevossian RG, Jacques TS, Sheer D, Kilday J, Wright K, Leavy S, Lowe J, Schwalbe E, Clifford S, Gilbertson R, Coyle B, Grundy R, Kinsella P, Clynes M, Amberger-Murphy V, Barron N, Lambert SR, Jones D, Pearson D, Ichimura I, Collins V, Steele L, Sinha P, Chumas P, Tyler J, Ogawa D, Chiocca E, DeLay M, Bronisz A, Nowicki M, Godlewski J, Lawler S, Lee MK, Javadpour M, Jenkinson MD, Lekka E, Abel P, Dawson T, Lea B, Davis C, Lim CSK, Grundy PL, Pendleton M, Lord H, Mackinnon M, Williamson A, James A, Stewart W, Clark B, Chalmers A, Merve A, Zhang X, Marino S, Miller S, Rogers HA, Lyon P, Rand V, Adamowicz-Brice M, Clifford SC, Hayden JT, Dyer S, Pfister S, Korshunov A, Brundler MA, Lowe J, Coyle B, Grundy RG, Nankivell M, Mulvenna P, Barton R, Wilson P, Faivre-Finn C, Pugh C, Langley R, Ngoga D, Tennant D, Williams A, Moss P, Cruickshank G, Owusu-Agyemang K, Bell S, Stewart W, St.George J, Piccirillo SG, Watts C, Qadri S, Pirola E, Jenkinson M, Brodbelt A, Rahman R, Rahman C, Smith S, MacArthur D, Rose F, Shakesheff K, Grundy R, Carroll C, Watson P, Hawkins M, Spoudeas H, Walker D, Holland T, Ring H, Rooney A, McNamara S, Mackinnon M, Fraser M, Rampling R, Carson A, Grant R, Royds J, Al Nadaf S, Ahn A, Chen YJ, Wiles A, Jellinek D, Braithwaite A, Baguley B, MacFarlane M, Hung N, Slatter T, Rusbridge S, Walmsley N, Griffiths S, Wilford P, Rees J, Ryan D, Watts C, Liu P, Galavotti S, Shaked-Rabi M, Tulchinsky E, Brandner S, Jones C, Salomoni P, Schulte A, Gunther HS, Zapf S, Riethdorf S, Westphal M, Lamszus K, Selvanathan SK, Hammouche S, Salminen HJ, Jenkinson MD, Setua S, Watts C, Welland ME, Shevtsov M, Khachatryan W, Kim A, Samochernych K, Pozdnyakov A, Guzhova IV, Romanova IV, Margulis B, Smith S, Rahman R, Rahman C, Barrow J, Macarthur D, Rose F, Grundy R, Smith S, Long A, Barrow J, Macarthur D, Coyle B, Grundy R, Maherally Z, Smith JR, Dickson L, Pilkington GJ, Prabhu S, Harris F, Lea R, Snape TJ, Sussman M, Wilne S, Whitehouse W, Chow G, Liu JF, Walker D, Snape T, Karakoula A, Rowther F, Warr T, Williamson A, Mackinnon M, Zisakis A, Varsos V, Panteli A, Karypidou O, Zampethanis A, Fotovati A, Abu-Ali S, Wang PS, Deleyrolle L, Lee C, Triscott J, Chen JY, Franciosi S, Nakamura Y, Sugita Y, Uchiumi T, Kuwano M, Leavitt BR, Singh SK, Jury A, Jones C, Wakimoto H, Reynolds BA, Pallen CJ, Dunn SE, Shepherd S, Scott S, Bowyer D, Wallace L, Hacking B, Mohsen L, Jena R, Gillard J, Price S, Lee C, Fotovati A, Verraeult M, Wakimoto H, Reynolds B, Dunham C, Bally M, Hukin J, Singhal S, Singh S, Dunn S. Abstracts from the 2011 BNOS Conference, June 29 - July 1, 2011, Homerton College, Cambridge. Neuro Oncol 2011. [DOI: 10.1093/neuonc/nor144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Anderton RS, Meloni BP, Mastaglia FL, Greene WK, Boulos S. Survival of motor neuron protein over-expression prevents calpain-mediated cleavage and activation of procaspase-3 in differentiated human SH-SY5Y cells. Neuroscience 2011; 181:226-33. [PMID: 21333717 DOI: 10.1016/j.neuroscience.2011.02.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 01/11/2011] [Accepted: 02/14/2011] [Indexed: 01/25/2023]
Abstract
Spinal muscular atrophy (SMA), a neurodegenerative disorder primarily affecting motor neurons, is the most common genetic cause of infant death. This incurable disease is caused by the absence of a functional SMN1 gene and a reduction in full length survival of motor neuron (SMN) protein. In this study, a neuroprotective function of SMN was investigated in differentiated human SH-SY5Y cells using an adenoviral vector to over-express SMN protein. The pro-survival capacity of SMN was assessed in an Akt/PI3-kinase inhibition (LY294002) model, as well as an oxidative stress (hydrogen peroxide) and excitotoxic (glutamate) model. SMN over-expression in SH-SY5Y cells protected against Akt/phosphatidylinositol 3-kinase (PI3-kinase) inhibition, but not oxidative stress, nor against excitotoxicity in rat cortical neurons. Western analysis of cell homogenates from SH-SY5Y cultures over-expressing SMN harvested pre- and post-Akt/PI3-kinase inhibition indicated that SMN protein inhibited caspase-3 activation via blockade of calpain-mediated procaspase-3 cleavage. This study has revealed a novel anti-apoptotic function for the SMN protein in differentiated SH-SY5Y cells. Finally, the cell death model described herein will allow the assessment of future therapeutic agents or strategies aimed at increasing SMN protein levels.
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Affiliation(s)
- R S Anderton
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia, WA, Australia.
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Boulos S, Gadallah M, Naguib S, Ezzat E, Youssef A, Cassano E, Miller A, Mittra I, Costa A. THE CAIRO BREAST SCREENING STUDY (CBCST). Maturitas 2009. [DOI: 10.1016/s0378-5122(09)70176-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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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Boulos S, Gadallah M, Neguib S, Essam E, Youssef A, Costa A, Mittra I, Miller AB. Breast screening in the emerging world: High prevalence of breast cancer in Cairo. Breast 2005; 14:340-6. [PMID: 16131468 DOI: 10.1016/j.breast.2005.07.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 07/11/2005] [Accepted: 07/13/2005] [Indexed: 10/25/2022] Open
Abstract
The Cairo Breast Screening Trial (CBST) was designed to evaluate the role of clinical breast examination as a primary screening modality in the context of primary care, as in Egypt breast cancer is usually diagnosed at an advanced stage. A specialised medical centre in Cairo (the Italian Hospital) was selected as the headquarters of the study. The initial target group was women age 35-64 living in a geographically defined area around the Italian Hospital, 4116 being contacted by social workers and invited to attend a Primary Health Centre for clinical breast examination. High rates of breast cancer were observed; 8 per 1000 at the first examination and approximately 2 per thousand among those who attended for re-screening. The initial prevalence suggests that many women in the community with early but palpable breast cancer fail to seek medical attention until their cancer is advanced. The detection rate on re-screening, and after follow-up of those who only received one or no screens, ( approximately 3/1000) is similar to expectation.
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Affiliation(s)
- S Boulos
- Italian Hospital, 18 Sarayat Street, Abassiah, Cairo, Egypt.
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Boulos S, Gadallah M, Naguib S, Ezzat E, Youssef A, Cassano E, Miller A, Mittra I, Costa A. How does Egypt cope? EJC Suppl 2004. [DOI: 10.1016/s1359-6349(04)90836-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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