1
|
Young TW, Kappler MP, Hockaden NM, Carpenter RL, Jacobson SC. Characterization of Extracellular Vesicles by Resistive-Pulse Sensing on In-Plane Multipore Nanofluidic Devices. Anal Chem 2023; 95:16710-16716. [PMID: 37916500 PMCID: PMC10841850 DOI: 10.1021/acs.analchem.3c03546] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Extracellular vesicles (EVs) are cell-derived, naturally produced, membrane-bound nanoscale particles that are linked to cell-cell communication and the propagation of diseases. Here, we report the design and testing of in-plane nanofluidic devices for resistive-pulse measurements of EVs derived from bovine milk and human breast cancer cells. The devices were fabricated in plane with three nanopores in series to determine the particle volume and diameter, two pore-to-pore regions to measure the electrophoretic mobility and zeta potential, and an in-line filter to prevent cellular debris and aggregates from entering the nanopore region. Devices were tested with and without the channels coated with a short-chain PEG silane to minimize electroosmotic flow and permit an accurate measurement of the electrophoretic mobility and zeta potential of the EVs. To enhance throughput of EVs, vacuum was applied to the waste reservoir to increase particle frequencies up to 1000 min-1. The nanopores had cross-sections 200 nm wide and 200 nm deep and easily resolved EV diameters from 60 to 160 nm. EVs from bovine milk and human breast cancer cells had similar particle size distributions, but their zeta potentials differed by 2-fold, -8 ± 1 and -4 ± 1 mV, respectively.
Collapse
Affiliation(s)
- Tanner W Young
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Michael P Kappler
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Natasha M Hockaden
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-Bloomington, Bloomington, Indiana 47405-7005, United States
| | - Richard L Carpenter
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine-Bloomington, Bloomington, Indiana 47405-7005, United States
| | - Stephen C Jacobson
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| |
Collapse
|
2
|
Esene JE, Nasman PR, Miner DS, Nordin GP, Woolley AT. High-performance microchip electrophoresis separations of preterm birth biomarkers using 3D printed microfluidic devices. J Chromatogr A 2023; 1706:464242. [PMID: 37595419 PMCID: PMC10473225 DOI: 10.1016/j.chroma.2023.464242] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 07/22/2023] [Accepted: 07/24/2023] [Indexed: 08/20/2023]
Abstract
We employed digital light processing-stereolithography 3D printing to create microfluidic devices with different designs for microchip electrophoresis (µCE). Short or long straight channel, and two- or four-turn serpentine channel microfluidic devices with separation channel lengths of 1.3, 3.1, 3.0, and 4.7 cm, respectively, all with a cross injector design, were fabricated. We measured current as a function of time and voltage to determine a separation time window and conditions for the onset of Joule heating in these designs. Separations in these devices were evaluated by performing µCE and measuring theoretical plate counts for electric field strengths near and above the onset of Joule heating, with fluorescently labeled glycine and phenylalanine as model analytes. We further demonstrated µCE of peptides and proteins related to preterm birth risk, showing increased peak capacity and resolution compared to previous results with 3D printed microdevices. These results mark an important step forward in the use of 3D printed microfluidic devices for rapid bioanalysis by µCE.
Collapse
Affiliation(s)
- Joule E Esene
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA
| | - Parker R Nasman
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA
| | - Dallin S Miner
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT, 84602, USA
| | - Gregory P Nordin
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT, 84602, USA
| | - Adam T Woolley
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, USA.
| |
Collapse
|
3
|
Zhou X, Song W, Novotny MV, Jacobson SC. Fractionation and characterization of sialyl linkage isomers of serum N-glycans by CE-MS. J Sep Sci 2022; 45:3348-3361. [PMID: 35819141 PMCID: PMC9473921 DOI: 10.1002/jssc.202200223] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 06/12/2022] [Accepted: 07/07/2022] [Indexed: 11/07/2022]
Abstract
Structural isomers of sialylated N-glycans contribute to the diversity of the N-glycome and to a range of biological functions. Sialyl linkage isomers can be readily distinguished by mass spectrometry with mass differences between α2,3- and α2,6-linkages generated by a two-step sialic acid linkage-specific alkylamidation. To improve the identification of N-glycans from complex mixtures, we added a delactonization step after the first alkylamidation step, which regenerates negatively charged carboxylic acids on α2,3-sialic acids. N-glycan isomers with α2,3-sialic acids are then fractionated by ion-exchange chromatography prior to the second alkylamidation step. With this modified alkylamidation method, sialylated N-glycans were enriched and stabilized for structural characterization by capillary electrophoresis-mass spectrometry and tandem mass spectrometry. We identified 52 sialylated N-glycan structures, including 107 linkage isomers, in human serum and confirmed the presence of positional isomers of specific sialyl linkage isomers. Due to the reduced sample complexity after ion-exchange fractionation and CE separation, substructural features of N-glycans were rapidly evaluated and included core- and antenna-fucosylation and poly-lactosamine.
Collapse
Affiliation(s)
- Xiaomei Zhou
- Department of Chemistry, Indiana University, Bloomington, Indiana 47401-7102, U.S.A
| | - Woran Song
- Department of Chemistry, Indiana University, Bloomington, Indiana 47401-7102, U.S.A
| | - Milos V. Novotny
- Department of Chemistry, Indiana University, Bloomington, Indiana 47401-7102, U.S.A
| | - Stephen C. Jacobson
- Department of Chemistry, Indiana University, Bloomington, Indiana 47401-7102, U.S.A
| |
Collapse
|
4
|
Cajic S, Hennig R, Burock R, Rapp E. Capillary (Gel) Electrophoresis-Based Methods for Immunoglobulin (G) Glycosylation Analysis. EXPERIENTIA SUPPLEMENTUM (2012) 2021; 112:137-172. [PMID: 34687009 DOI: 10.1007/978-3-030-76912-3_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The in-depth characterization of protein glycosylation has become indispensable in many research fields and in the biopharmaceutical industry. Especially knowledge about modulations in immunoglobulin G (IgG) N-glycosylation and their effect on immunity enabled a better understanding of human diseases and the development of new, more effective drugs for their treatment. This chapter provides a deeper insight into capillary (gel) electrophoresis-based (C(G)E) glycan analysis, addressing its impressive performance and possibilities, its great potential regarding real high-throughput for large cohort studies, as well as its challenges and limitations. We focus on the latest developments with respect to miniaturization and mass spectrometry coupling, as well as data analysis and interpretation. The use of exoglycosidase sequencing in combination with current C(G)E technology is discussed, highlighting possible difficulties and pitfalls. The application section describes the detailed characterization of N-glycosylation, utilizing multiplexed CGE with laser-induced fluorescence detection (xCGE-LIF). Besides a comprehensive overview on antibody glycosylation by comparing species-specific IgGs and human immunoglobulins A, D, E, G, and M, the chapter comprises a comparison of therapeutic monoclonal antibodies from different production cell lines, as well as a detailed characterization of Fab and Fc glycosylation. These examples illustrate the full potential of C(G)E, resolving the smallest differences in sugar composition and structure.
Collapse
Affiliation(s)
- Samanta Cajic
- Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - René Hennig
- Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.
- glyXera GmbH, Magdeburg, Germany.
| | | | - Erdmann Rapp
- Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
- glyXera GmbH, Magdeburg, Germany
| |
Collapse
|
5
|
Mehl BT, Martin RS. Enhanced Microchip Electrophoresis Separations Combined with Electrochemical Detection Utilizing a Capillary Embedded in Polystyrene. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2018; 10:37-45. [PMID: 29707044 PMCID: PMC5915312 DOI: 10.1039/c7ay02505j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The ability to use microchip-based electrophoresis for fast, high-throughput separations provides researchers with a tool for close-to real time analysis of biological systems. While PDMS-based electrophoresis devices are popular, the separation efficiency is often an issue due to the hydrophobic nature of PDMS. In this study, a hybrid microfluidic capillary device was fabricated to utilize the positive features of PDMS along with the electrophoretic performance of fused silica. A capillary loop was embedded in a polystyrene base that can be coupled with PDMS microchannels at minimal dead volume interconnects. A method for cleaning out the capillaries after a wet-polishing step was devised through the use of 3D printed syringe attachment. By comparing the separation efficiency of fluorescein and CBI-glycine with both a PDMS-based serpentine device and the embedded capillary loop device, it was shown that the embedded capillary loop device maintained higher theoretical plates for both analytes. A Pd decoupler with a carbon or Pt detection electrode were embedded along with the loop allowing integration of the electrophoretic separation with electrochemical detection. A series of catecholamines were separated to show the ability to resolve similar analytes and detect redox active species. The release of dopamine and norepinephrine from PC 12 cells was also analyzed showing the compatibility of these improved microchip separations with high ionic cell buffers associated with cell culture.
Collapse
|
6
|
Pan Q, Herr AE. Geometry-induced injection dispersion in single-cell protein electrophoresis. Anal Chim Acta 2017; 1000:214-222. [PMID: 29289313 DOI: 10.1016/j.aca.2017.11.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 11/15/2017] [Accepted: 11/16/2017] [Indexed: 10/18/2022]
Abstract
Arrays of microwells are widely used to isolate individual cells, facilitate high throughput cytometry assays, and ensure compatibility of those assays with whole-cell imaging. Microwell geometries have recently been utilized for handling and preparation of single-cell lysate, prior to single-cell protein electrophoresis. It is in the context of single-cell electrophoresis that we investigate the interplay of microwell geometry (circular, rectangular, triangular) and transport (diffusion, electromigration) on the subsequent performance of single-cell polyacrylamide gel electrophoresis (PAGE) for protein targets. We define and measure injector-induced dispersion during PAGE, and develop a numerical model of band broadening sources, experimentally validate the numerical model, and then identify operating conditions (characterized through the Peclet number, Pe) that lead to microwell-geometry induced losses in separation performance. With analysis of mammalian cells as a case study, we sought to understand at what Pe is the PAGE separation performance adversely sensitized to the microwell geometry. In developing design rules, we find that for the microwell geometries that are the most suitable for isolation of mammalian cells and moderate mass protein targets, the Pe is usually small enough (Pe < ∼20) to mitigate the effect of the microwell geometry on protein PAGE of single-cell lysate. In extreme cases where the largest mammalian cells are analyzed (Pe > ∼20), consideration of Pe suggests using a rectangular - and not the widely used circular - microwell geometry to maximize protein PAGE separation performance.
Collapse
Affiliation(s)
- Qiong Pan
- Department of Bioengineering, University of California Berkeley, Berkeley, CA 94720, United States
| | - Amy E Herr
- Department of Bioengineering, University of California Berkeley, Berkeley, CA 94720, United States.
| |
Collapse
|
7
|
Mantovani V, Galeotti F, Maccari F, Volpi N. Recent advances in capillary electrophoresis separation of monosaccharides, oligosaccharides, and polysaccharides. Electrophoresis 2017; 39:179-189. [DOI: 10.1002/elps.201700290] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/22/2017] [Accepted: 08/23/2017] [Indexed: 01/26/2023]
Affiliation(s)
- Veronica Mantovani
- Department of Life Sciences; University of Modena and Reggio Emilia; Modena Italy
| | - Fabio Galeotti
- Department of Life Sciences; University of Modena and Reggio Emilia; Modena Italy
| | - Francesca Maccari
- Department of Life Sciences; University of Modena and Reggio Emilia; Modena Italy
| | - Nicola Volpi
- Department of Life Sciences; University of Modena and Reggio Emilia; Modena Italy
| |
Collapse
|
8
|
Snyder CM, Zhou X, Karty JA, Fonslow BR, Novotny MV, Jacobson SC. Capillary electrophoresis-mass spectrometry for direct structural identification of serum N-glycans. J Chromatogr A 2017; 1523:127-139. [PMID: 28989033 DOI: 10.1016/j.chroma.2017.09.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 09/01/2017] [Accepted: 09/03/2017] [Indexed: 10/18/2022]
Abstract
Through direct coupling of capillary electrophoresis (CE) to mass spectrometry (MS) with a sheathless interface, we have identified 77 potential N-glycan structures derived from human serum. We confirmed the presence of N-glycans previously identified by indirect methods, e.g., electrophoretic mobility standards, obtained 31 new N-glycan structures not identified in our prior work, differentiated co-migrating structures, and determined specific linkages on isomers featuring sialic acids. Serum N-glycans were cleaved from proteins, neutralized via methylamidation, and labeled with the fluorescent tag 8-aminopyrene-1,3,6-trisulfonic acid, which renders the glycan fluorescent and provides a -3 charge for electrophoresis and negative-mode MS detection. The neutralization reaction also stabilizes the labile sialic acids. In addition to methylamidation, native charges from sialic acids were neutralized through reaction with 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium to amidate α2,6-linked sialic acids in the presence of ammonium chloride and form lactones with α2,3-linked sialic acids. This neutralization effectively labels each type of sialic acid with a unique mass to determine specific linkages on sialylated N-glycans. For both neutralization schemes, we compared the results from microchip electrophoresis and CE.
Collapse
Affiliation(s)
- Christa M Snyder
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, United States
| | - Xiaomei Zhou
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, United States
| | - Jonathan A Karty
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, United States
| | | | - Milos V Novotny
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, United States
| | - Stephen C Jacobson
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, United States.
| |
Collapse
|
9
|
Affiliation(s)
- Stefan Gaunitz
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Gabe Nagy
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Nicola L. B. Pohl
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Milos V. Novotny
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
- Regional Center for Applied Molecular Oncology, Masaryk Memorial Oncological Institute, 656 53 Brno, Czech Republic
| |
Collapse
|
10
|
Mitra I, Snyder CM, Zhou X, Campos MI, Alley WR, Novotny MV, Jacobson SC. Structural Characterization of Serum N-Glycans by Methylamidation, Fluorescent Labeling, and Analysis by Microchip Electrophoresis. Anal Chem 2016; 88:8965-71. [PMID: 27504786 DOI: 10.1021/acs.analchem.6b00882] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
To characterize the structures of N-glycans derived from human serum, we report a strategy that combines microchip electrophoresis, standard addition, enzymatic digestion, and matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). We compared (i) electrophoretic mobilities of known N-glycans from well-characterized (standard) glycoproteins through standard addition, (ii) the electrophoretic mobilities of N-glycans with their molecular weights determined by MALDI-MS, and (iii) electrophoretic profiles of N-glycans enzymatically treated with fucosidase. The key step to identify the sialylated N-glycans was to quantitatively neutralize the negative charge on both α2,3- and α2,6-linked sialic acids by covalent derivatization with methylamine. Both neutralized and nonsialylated N-glycans from these samples were then reacted with 8-aminopyrene-1,3,6-trisulfonic acid (APTS) to provide a fluorescent label and a triple-negative charge, separated by microchip electrophoresis, and detected by laser-induced fluorescence. The methylamidation step leads to a 24% increase in the peak capacity of the separation and direct correlation of electrophoretic and MALDI-MS results. In total, 37 unique N-glycan structures were assigned to 52 different peaks recorded in the electropherograms of the serum samples. This strategy ensures the needed separation efficiency and detectability, easily resolves linkage and positional glycan isomers, and is highly reproducible.
Collapse
Affiliation(s)
- Indranil Mitra
- Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States
| | - Christa M Snyder
- Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States
| | - Xiaomei Zhou
- Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States
| | - Margit I Campos
- Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States
| | - William R Alley
- Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States
| | - Milos V Novotny
- Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States
| | - Stephen C Jacobson
- Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States
| |
Collapse
|
11
|
Hajba L, Csanky E, Guttman A. Liquid phase separation methods for N-glycosylation analysis of glycoproteins of biomedical and biopharmaceutical interest. A critical review. Anal Chim Acta 2016; 943:8-16. [PMID: 27769380 DOI: 10.1016/j.aca.2016.08.035] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 12/25/2022]
Abstract
Comprehensive carbohydrate analysis of glycoproteins from human biological samples and biotherapeutics are important from diagnostic and therapeutic points of view. This review summarizes the current state-of-the-art liquid phase separation techniques used in N-glycosylation analysis. The different liquid chromatographic techniques and capillary electrophoresis methods are critically discussed in detail. Miniaturization of these methods is also important to increase throughput and decrease analysis time. The sample preparation and labeling methods for asparagine linked oligosaccharides are also addressed.
Collapse
Affiliation(s)
- Laszlo Hajba
- MTA-PE Translational Glycomics Research Group, University of Pannonia, Veszprem, Hungary
| | | | - Andras Guttman
- MTA-PE Translational Glycomics Research Group, University of Pannonia, Veszprem, Hungary; Horvath Csaba Laboratory of Bioseparation Sciences, University of Debrecen, Debrecen, Hungary.
| |
Collapse
|
12
|
Yamamoto S, Kinoshita M, Suzuki S. Current landscape of protein glycosylation analysis and recent progress toward a novel paradigm of glycoscience research. J Pharm Biomed Anal 2016; 130:273-300. [PMID: 27461579 DOI: 10.1016/j.jpba.2016.07.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 07/09/2016] [Accepted: 07/09/2016] [Indexed: 12/25/2022]
Abstract
This review covers the basics and some applications of methodologies for the analysis of glycoprotein glycans. Analytical techniques used for glycoprotein glycans, including liquid chromatography (LC), capillary electrophoresis (CE), mass spectrometry (MS), and high-throughput analytical methods based on microfluidics, were described to supply the essentials about biopharmaceutical and biomarker glycoproteins. We will also describe the MS analysis of glycoproteins and glycopeptides as well as the chemical and enzymatic releasing methods of glycans from glycoproteins and the chemical reactions used for the derivatization of glycans. We hope the techniques have accommodated most of the requests from glycoproteomics researchers.
Collapse
Affiliation(s)
- Sachio Yamamoto
- Faculty of Pharmaceutical Sciences, Kinki University, 3-4-1, Kowakae, Higashi-osaka, Osaka, 577-8502, Japan.
| | - Mitsuhiro Kinoshita
- Faculty of Pharmaceutical Sciences, Kinki University, 3-4-1, Kowakae, Higashi-osaka, Osaka, 577-8502, Japan
| | - Shigeo Suzuki
- Faculty of Pharmaceutical Sciences, Kinki University, 3-4-1, Kowakae, Higashi-osaka, Osaka, 577-8502, Japan
| |
Collapse
|
13
|
Recent applications of microchip electrophoresis to biomedical analysis. J Pharm Biomed Anal 2015; 113:72-96. [DOI: 10.1016/j.jpba.2015.03.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 02/28/2015] [Accepted: 03/03/2015] [Indexed: 11/22/2022]
|
14
|
Yang Z, Sweedler JV. Application of capillary electrophoresis for the early diagnosis of cancer. Anal Bioanal Chem 2014; 406:4013-31. [DOI: 10.1007/s00216-014-7722-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 02/18/2014] [Accepted: 02/21/2014] [Indexed: 02/07/2023]
|
15
|
Mitra I, Marczak SP, Jacobson SC. Microchip electrophoresis at elevated temperatures and high separation field strengths. Electrophoresis 2013; 35:374-8. [PMID: 24114979 DOI: 10.1002/elps.201300427] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/03/2013] [Accepted: 09/05/2013] [Indexed: 11/11/2022]
Abstract
We report free-solution microchip electrophoresis performed at elevated temperatures and high separation field strengths. We used microfluidic devices with 11 cm long separation channels to conduct separations at temperatures between 22 (ambient) and 45°C and field strengths from 100 to 1000 V/cm. To evaluate separation performance, N-glycans were used as a model system and labeled with 8-aminopyrene-1,3,6-trisulfonic acid to impart charge for electrophoresis and render them fluorescent. Typically, increased diffusivity at higher temperatures leads to increased axial dispersion and poor separation performance; however, we demonstrate that sufficiently high separation field strengths offset the impact of increased diffusivity in order to maintain separation efficiency. Efficiencies for these free-solution separations are the same at temperatures of 25, 35, and 45°C with separation field strengths ≥ 500 V/cm.
Collapse
Affiliation(s)
- Indranil Mitra
- Department of Chemistry, Indiana University, Bloomington, IN, USA
| | | | | |
Collapse
|
16
|
Mitra I, Alley WR, Goetz JA, Vasseur JA, Novotny MV, Jacobson SC. Comparative profiling of N-glycans isolated from serum samples of ovarian cancer patients and analyzed by microchip electrophoresis. J Proteome Res 2013; 12:4490-6. [PMID: 23984816 DOI: 10.1021/pr400549e] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ovarian cancer is the fifth leading cause of cancer-related mortalities for women in the United States and the most lethal gynecological cancer. Aberrant glycosylation has been linked to several human diseases, including ovarian cancer, and accurate measurement of changes in glycosylation may provide relevant diagnostic and prognostic information. In this work, we used microchip electrophoresis coupled with laser-induced fluorescence detection to determine quantitative differences among the N-glycan profiles of control individuals and late-stage recurrent ovarian cancer patients prior to and after an experimental drug treatment that combined docetaxel and imatinib mesylate. N-Glycans were enzymatically released from 5-μL aliquots of serum samples, labeled with the anionic fluorescent tag, 8-aminopyrene-1,3,6-trisulfonic acid, and analyzed on microfluidic devices. A 22-cm long separation channel, operated at 1250 V/cm, generated analysis times less than 100 s, separation efficiencies up to 8 × 10(5) plates (3.6 × 10(6) plates/m), and migration time reproducibilities better than 0.1% relative standard deviation after peak alignment. Principal component analysis (PCA) and analysis of variance (ANOVA) tests showed significant differences between the control and both pre- and post-treatment cancer samples and subtle differences between the pre- and post-treatment cancer samples. Area-under-the-curve (AUC) values from receiver operating characteristics (ROC) tests were used to evaluate the diagnostic merit of N-glycan peaks, and specific N-glycan peaks used in combination provided AUCs > 0.90 (highly accurate test) when the control and pretreatment cancer samples and control and post-treatment samples were compared.
Collapse
Affiliation(s)
- Indranil Mitra
- Department of Chemistry, Indiana University , Bloomington, Indiana 47405, United States
| | | | | | | | | | | |
Collapse
|
17
|
Novotny MV, Alley WR. Recent trends in analytical and structural glycobiology. Curr Opin Chem Biol 2013; 17:832-40. [PMID: 23790311 DOI: 10.1016/j.cbpa.2013.05.029] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 05/24/2013] [Indexed: 12/22/2022]
Abstract
The great complexity of glycosylated biomolecules necessitates a set of powerful analytical methodologies to reveal functionally important structural features. Mass spectrometry (MS), with its different ionization techniques, mass analyzers, and detection strategies, has become the most important analytical method in glycomic and glycoproteomic investigations. In combination with MS, microscale separations (based on capillary chromatography and electrophoresis) and carbohydrate microchemistry, we feature here conceptually important applications of the recent years. This review focuses on methodological advances pertaining to disease biomarker research, immunology, developmental biology, and measurements of importance to biopharmaceuticals. High-sensitivity determinations and sample enrichment/preconcentration are particularly emphasized in glycomic and glycoproteomic profiling.
Collapse
Affiliation(s)
- Milos V Novotny
- Department of Chemistry, Indiana University, Bloomington, IN 47405, United States.
| | | |
Collapse
|
18
|
Mittermayr S, Bones J, Guttman A. Unraveling the Glyco-Puzzle: Glycan Structure Identification by Capillary Electrophoresis. Anal Chem 2013; 85:4228-38. [DOI: 10.1021/ac4006099] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Stefan Mittermayr
- Horváth
Laboratory of
Bioseparation Sciences, Regional Center for Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Jonathan Bones
- NIBRT−The National Institute for Bioprocessing Research and Training, Fosters Avenue, Mount Merrion, Blackrock, Co. Dublin, Ireland
| | - András Guttman
- Horváth
Laboratory of
Bioseparation Sciences, Regional Center for Molecular Medicine, University of Debrecen, Debrecen, Hungary
- MTA-PE Translational Glycomics
Group, University of Pannonia, Veszprem,
Hungary
| |
Collapse
|
19
|
Alley WR, Mann BF, Novotny MV. High-sensitivity analytical approaches for the structural characterization of glycoproteins. Chem Rev 2013; 113:2668-732. [PMID: 23531120 PMCID: PMC3992972 DOI: 10.1021/cr3003714] [Citation(s) in RCA: 239] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- William R. Alley
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States
- National Center for Glycomics and Glycoproteomics, Indiana University, Bloomington, Indiana, United States
| | - Benjamin F. Mann
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States
- National Center for Glycomics and Glycoproteomics, Indiana University, Bloomington, Indiana, United States
| | - Milos V. Novotny
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States
- National Center for Glycomics and Glycoproteomics, Indiana University, Bloomington, Indiana, United States
- Indiana University School of Medicine, Indiana University, Indianapolis, Indiana, United States
| |
Collapse
|
20
|
Nge PN, Rogers CI, Woolley AT. Advances in microfluidic materials, functions, integration, and applications. Chem Rev 2013; 113:2550-83. [PMID: 23410114 PMCID: PMC3624029 DOI: 10.1021/cr300337x] [Citation(s) in RCA: 519] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Pamela N. Nge
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
| | - Chad I. Rogers
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
| | - Adam T. Woolley
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602
| |
Collapse
|
21
|
Nandi P, Scott DE, Desai D, Lunte SM. Development and optimization of an integrated PDMS based-microdialysis microchip electrophoresis device with on-chip derivatization for continuous monitoring of primary amines. Electrophoresis 2013; 34:895-902. [PMID: 23335091 PMCID: PMC3744098 DOI: 10.1002/elps.201200454] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 11/20/2012] [Accepted: 11/23/2012] [Indexed: 01/08/2023]
Abstract
An all-PDMS on-line microdialysis-microchip electrophoresis with on-chip derivatization and electrophoretic separation for near real-time monitoring of primary amine-containing analytes is described. Each part of the chip was optimized separately, and the effect of each of the components on temporal resolution, lag time, and separation efficiency of the device was determined. Aspartate and glutamate were employed as test analytes. Derivatization was accomplished with naphthalene-2,3,-dicarboxyaldehyde/cyanide (NDA/CN(-)), and the separation was performed using a 15-cm serpentine channel. The analytes were detected using LIF detection.
Collapse
Affiliation(s)
- Pradyot Nandi
- Department of Pharmaceutical, Chemistry, University of Kansas, Lawrence, KS, USA
- Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS, USA
| | - David E. Scott
- Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS, USA
- Department of Chemistry, University of Kansas, Lawrence, KS, USA
| | - Dhara Desai
- Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS, USA
- Department of Chemistry, University of Kansas, Lawrence, KS, USA
| | - Susan M. Lunte
- Department of Pharmaceutical, Chemistry, University of Kansas, Lawrence, KS, USA
- Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS, USA
- Department of Chemistry, University of Kansas, Lawrence, KS, USA
| |
Collapse
|
22
|
Novotny MV, Alley WR, Mann BF. Analytical glycobiology at high sensitivity: current approaches and directions. Glycoconj J 2013; 30:89-117. [PMID: 22945852 PMCID: PMC3586546 DOI: 10.1007/s10719-012-9444-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Revised: 06/29/2012] [Accepted: 08/14/2012] [Indexed: 12/30/2022]
Abstract
This review summarizes the analytical advances made during the last several years in the structural and quantitative determinations of glycoproteins in complex biological mixtures. The main analytical techniques used in the fields of glycomics and glycoproteomics involve different modes of mass spectrometry and their combinations with capillary separation methods such as microcolumn liquid chromatography and capillary electrophoresis. The need for high-sensitivity measurements have been emphasized in the oligosaccharide profiling used in the field of biomarker discovery through MALDI mass spectrometry. High-sensitivity profiling of both glycans and glycopeptides from biological fluids and tissue extracts has been aided significantly through lectin preconcentration and the uses of affinity chromatography.
Collapse
Affiliation(s)
- Milos V Novotny
- Department of Chemistry, Indiana University, Bloomington, IN, USA.
| | | | | |
Collapse
|
23
|
Mechref Y, Hu Y, Desantos-Garcia JL, Hussein A, Tang H. Quantitative glycomics strategies. Mol Cell Proteomics 2013; 12:874-84. [PMID: 23325767 DOI: 10.1074/mcp.r112.026310] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The correlations between protein glycosylation and many biological processes and diseases are increasing the demand for quantitative glycomics strategies enabling sensitive monitoring of changes in the abundance and structure of glycans. This is currently attained through multiple strategies employing several analytical techniques such as capillary electrophoresis, liquid chromatography, and mass spectrometry. The detection and quantification of glycans often involve labeling with ionic and/or hydrophobic reagents. This step is needed in order to enhance detection in spectroscopic and mass spectrometric measurements. Recently, labeling with stable isotopic reagents has also been presented as a very viable strategy enabling relative quantitation. The different strategies available for reliable and sensitive quantitative glycomics are herein described and discussed.
Collapse
Affiliation(s)
- Yehia Mechref
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, USA.
| | | | | | | | | |
Collapse
|
24
|
Alley WR, Novotny MV. Structural glycomic analyses at high sensitivity: a decade of progress. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2013; 6:237-65. [PMID: 23560930 PMCID: PMC3992932 DOI: 10.1146/annurev-anchem-062012-092609] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The field of glycomics has recently advanced in response to the urgent need for structural characterization and quantification of complex carbohydrates in biologically and medically important applications. The recent success of analytical glycobiology at high sensitivity reflects numerous advances in biomolecular mass spectrometry and its instrumentation, capillary and microchip separation techniques, and microchemical manipulations of carbohydrate reactivity. The multimethodological approach appears to be necessary to gain an in-depth understanding of very complex glycomes in different biological systems.
Collapse
Affiliation(s)
- William R. Alley
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405
| | - Milos V. Novotny
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405
- Department of Medicine, Indiana University, Indianapolis, Indiana 46202
| |
Collapse
|
25
|
Lazar IM, Lee W, Lazar AC. Glycoproteomics on the rise: established methods, advanced techniques, sophisticated biological applications. Electrophoresis 2012; 34:113-25. [PMID: 23161435 DOI: 10.1002/elps.201200445] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Revised: 10/07/2012] [Accepted: 10/07/2012] [Indexed: 02/05/2023]
Abstract
Glycosylation is the most complex form of protein PTMs. Affected proteins may carry dozens of glycosylation sites with tens to hundreds of glycan residues attached to every site. Glycosylated proteins have many important functions in biology, from cellular to organismal levels, being involved in cell-cell signaling, cell adhesion, immune response, host-pathogen interactions, and development and growth. Glycosylation, however, expands the biological functional diversity of proteins at the expense of a tremendous increase in structural heterogeneity. Aberrant glycosylation of cell surface proteins, as well as their detectable fingerprint in plasma samples, has been associated with cancer, inflammatory and degenerative diseases, and congenital disorders of glycosylation. Therefore, there are on-going efforts directed toward developing new technologies and approaches for glycan sequencing and high-throughput analysis of glycosylated proteins in complex samples with simultaneous characterization of both the protein and glycan moieties. This work is aimed primarily at pinpointing the challenges associated with the large-scale analysis of glycoproteins and the latest developments in glycoproteomic research, with focus on recent advancements (2011-2012) in microcolumn separations and MS detection.
Collapse
Affiliation(s)
- Iulia M Lazar
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
| | | | | |
Collapse
|
26
|
Mitra I, Zhuang Z, Zhang Y, Yu CY, Hammoud ZT, Tang H, Mechref Y, Jacobson SC. N-glycan profiling by microchip electrophoresis to differentiate disease states related to esophageal adenocarcinoma. Anal Chem 2012; 84:3621-7. [PMID: 22397697 DOI: 10.1021/ac203431s] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We report analysis of N-glycans derived from disease-free individuals and patients with Barrett's esophagus, high-grade dysplasia, and esophageal adenocarcinoma by microchip electrophoresis with laser-induced fluorescence detection. Serum samples in 10 μL aliquots are enzymatically treated to cleave the N-glycans that are subsequently reacted with 8-aminopyrene-1,3,6-trisulfonic acid to add charge and a fluorescent label. Separations at 1250 V/cm and over 22 cm yielded efficiencies up to 700,000 plates for the N-glycans and analysis times under 100 s. Principal component analysis (PCA) and analysis of variance (ANOVA) tests of the peak areas and migration times are used to evaluate N-glycan profiles from native and desialylated samples and determine differences among the four sample groups. With microchip electrophoresis, we are able to distinguish the three patient groups from each other and from disease-free individuals.
Collapse
Affiliation(s)
- Indranil Mitra
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Ruiz-May E, Thannhauser TW, Zhang S, Rose JKC. Analytical technologies for identification and characterization of the plant N-glycoproteome. FRONTIERS IN PLANT SCIENCE 2012; 3:150. [PMID: 22783270 PMCID: PMC3389394 DOI: 10.3389/fpls.2012.00150] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 06/18/2012] [Indexed: 05/09/2023]
Abstract
N-glycosylation is one of the most common and complex post-translational modifications of eukaryotic proteins and one that has numerous roles, such as modulating protein stability, sorting, folding, enzyme activity, and ligand interactions. In plants, the functional significance of N-glycosylation is typically obscure, although it is a feature of most secreted proteins and so is potentially of considerable interest to plant cell wall biologists. While analytical pipelines have been established to characterize yeast, mammalian, and bacterial N-glycoproteomes, such large-scale approaches for the study of plant glycoproteins have yet to be reported. Indeed, the N-glycans that decorate plant and mammalian or yeast proteins are structurally distinct and so modification of existing analytical approaches are needed to tackle plant N-glycoproteomes. In this review, we summarize a range of existing technologies for large-scale N-glycoprotein analysis and highlight promising future approaches that may provide a better understanding of the plant N-glycoproteome, and therefore the cell wall proteome and other proteins associated with the secretory pathway.
Collapse
Affiliation(s)
- Eliel Ruiz-May
- Department of Plant Biology, Cornell University,Ithaca, NY, USA
| | | | - Sheng Zhang
- Institute for Biotechnology and Life Science Technologies, Cornell University,Ithaca, NY, USA
| | - Jocelyn K. C. Rose
- Department of Plant Biology, Cornell University,Ithaca, NY, USA
- *Correspondence: Jocelyn K. C. Rose, Department of Plant Biology, Cornell University, 412 Mann Library Building, Ithaca, NY 14853, USA. e-mail:
| |
Collapse
|
28
|
Mechref Y. Analysis of glycans derived from glycoconjugates by capillary electrophoresis-mass spectrometry. Electrophoresis 2011; 32:3467-81. [PMID: 22180203 PMCID: PMC3360420 DOI: 10.1002/elps.201100342] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The high structural variation of glycan derived from glycoconjugates, which substantially increases with the molecular size of a protein, contributes to the complexity of glycosylation patterns commonly associated with glycoconjugates. In the case of glycoproteins, such variation originates from the multiple glycosylation sites of proteins and the number of glycan structures associated with each site (microheterogeneity). The ability to comprehensively characterize highly complex mixture of glycans has been analytically stimulating and challenging. Although the most powerful MS and MS/MS techniques are capable of providing a wealth of structural information, they are still not able to readily identify isomeric glycan structures without high-order MS/MS (MS(n) ). The analysis of isomeric glycan structures has been attained using several separation methods, including high-pH anion-exchange chromatography, hydrophilic interaction chromatography and GC. However, CE and microfluidics CE (MCE) offer high separation efficiency and resolutions, allowing the separation of closely related glycan structures. Therefore, interfacing CE and MCE to MS is a powerful analytical approach, allowing potentially comprehensive and sensitive analysis of complex glycan samples. This review describes and discusses the utility of different CE and MCE approaches in the structural characterization of glycoproteins and the feasibility of interfacing these approaches to MS.
Collapse
Affiliation(s)
- Yehia Mechref
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA.
| |
Collapse
|
29
|
Archer-Hartmann SA, Crihfield CL, Holland LA. Online enzymatic sequencing of glycans from Trastuzumab by phospholipid-assisted capillary electrophoresis. Electrophoresis 2011; 32:3491-8. [DOI: 10.1002/elps.201100432] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 09/19/2011] [Accepted: 09/21/2011] [Indexed: 12/17/2022]
|
30
|
Joshi H, Singharoy A, Sereda YV, Cheluvaraja SC, Ortoleva PJ. Multiscale simulation of microbe structure and dynamics. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 107:200-17. [PMID: 21802438 PMCID: PMC3383072 DOI: 10.1016/j.pbiomolbio.2011.07.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 07/01/2011] [Indexed: 10/18/2022]
Abstract
A multiscale mathematical and computational approach is developed that captures the hierarchical organization of a microbe. It is found that a natural perspective for understanding a microbe is in terms of a hierarchy of variables at various levels of resolution. This hierarchy starts with the N -atom description and terminates with order parameters characterizing a whole microbe. This conceptual framework is used to guide the analysis of the Liouville equation for the probability density of the positions and momenta of the N atoms constituting the microbe and its environment. Using multiscale mathematical techniques, we derive equations for the co-evolution of the order parameters and the probability density of the N-atom state. This approach yields a rigorous way to transfer information between variables on different space-time scales. It elucidates the interplay between equilibrium and far-from-equilibrium processes underlying microbial behavior. It also provides framework for using coarse-grained nanocharacterization data to guide microbial simulation. It enables a methodical search for free-energy minimizing structures, many of which are typically supported by the set of macromolecules and membranes constituting a given microbe. This suite of capabilities provides a natural framework for arriving at a fundamental understanding of microbial behavior, the analysis of nanocharacterization data, and the computer-aided design of nanostructures for biotechnical and medical purposes. Selected features of the methodology are demonstrated using our multiscale bionanosystem simulator DeductiveMultiscaleSimulator. Systems used to demonstrate the approach are structural transitions in the cowpea chlorotic mosaic virus, RNA of satellite tobacco mosaic virus, virus-like particles related to human papillomavirus, and iron-binding protein lactoferrin.
Collapse
Affiliation(s)
- Harshad Joshi
- Center for Cell and Virus Theory, Department of Chemistry, Indiana University, Bloomington, IN 47405 U. S. A
| | - Abhishek Singharoy
- Center for Cell and Virus Theory, Department of Chemistry, Indiana University, Bloomington, IN 47405 U. S. A
| | - Yuriy V. Sereda
- Center for Cell and Virus Theory, Department of Chemistry, Indiana University, Bloomington, IN 47405 U. S. A
| | - Srinath C. Cheluvaraja
- Center for Cell and Virus Theory, Department of Chemistry, Indiana University, Bloomington, IN 47405 U. S. A
| | - Peter J. Ortoleva
- Center for Cell and Virus Theory, Department of Chemistry, Indiana University, Bloomington, IN 47405 U. S. A
| |
Collapse
|