1
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Morris EP, Knupp C, Luther PK. Obituary: Professor John Michael Squire. J Muscle Res Cell Motil 2023; 44:125-132. [PMID: 37665489 DOI: 10.1007/s10974-023-09656-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 08/02/2023] [Indexed: 09/05/2023]
Affiliation(s)
- Edward P Morris
- School of Molecular Biosciences, University of Glasgow, Garscube Campus, Jarrett Building, 351, Bearsden Road, Glasgow, G61 1QH, UK
| | - Carlo Knupp
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF10 3AT, UK
| | - Pradeep K Luther
- Cardiac Function Section NHLI, Imperial College London, Hammersmith Campus ICTEM Building, Du Cane Road, London, W12 0NN, UK.
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2
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Yao T, Janaswamy S. Ordered hydrocolloids networks as delivery vehicles of nutraceuticals: Optimal encapsulation of curcumin and resveratrol. Food Hydrocoll 2022. [DOI: 10.1016/j.foodhyd.2021.107466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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3
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Zhao N, Yang C, Bian F, Guo D, Ouyang X. SGTools: a suite of tools for processing and analyzing large data sets from in situ X-ray scattering experiments. J Appl Crystallogr 2022. [DOI: 10.1107/s1600576721012267] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In situ synchrotron small-angle X-ray scattering (SAXS) is a powerful tool for studying dynamic processes during material preparation and application. The processing and analysis of large data sets generated from in situ X-ray scattering experiments are often tedious and time consuming. However, data processing software for in situ experiments is relatively rare, especially for grazing-incidence small-angle X-ray scattering (GISAXS). This article presents an open-source software suite (SGTools) to perform data processing and analysis for SAXS and GISAXS experiments. The processing modules in this software include (i) raw data calibration and background correction; (ii) data reduction by multiple methods; (iii) animation generation and intensity mapping for in situ X-ray scattering experiments; and (iv) further data analysis for the sample with an order degree and interface correlation. This article provides the main features and framework of SGTools. The workflow of the software is also elucidated to allow users to develop new features. Three examples are demonstrated to illustrate the use of SGTools for dealing with SAXS and GISAXS data. Finally, the limitations and future features of the software are also discussed.
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4
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Shao C, Zhang Z, Jin W, Zhang Z, Jin B, Jiang S, Pan H, Tang R, De Yoreo JJ, Liu XY. Oriented Crystallization of Hydroxyapatite in Self-Assembled Peptide Fibrils as a Bonelike Material. ACS Biomater Sci Eng 2021; 9:1808-1814. [PMID: 34855358 DOI: 10.1021/acsbiomaterials.1c00713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Controlling oriented crystallization is key to producing bonelike composite materials with a well-organized structure. However, producing this type of composite material using synthetic biopolymers as scaffolds is challenging. Inspired by the molecular structure of collagen-I, a collagenlike peptide─(Pro-Hyp-Gly)10 (POG10)─was designed to produce self-assembled fibrils that resemble the structure of collagen-I fibrils. In addition, the oriented mineralization of HAP crystals is formed in the fibrils that reproduces a bonelike material similar to collagen-I fibril mineralization. Unlike collagen-I fibrils, POG10 fibrils do not contain gap spaces. The molecular simulation results indicate that in addition to space confinement, the molecular field generated by POG10 can also confine the orientation of HAP, enriching our understanding of physical confinement and shedding light on the design of synthetic biopolymer scaffolds for bonelike material fabrication.
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Affiliation(s)
- Changyu Shao
- Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou 310027, China.,Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Zhisen Zhang
- College of Physical Science and Technology, Xiamen University, Xiamen 361005, China
| | - Wenjing Jin
- Affiliated Hospital of Stomatology, School of Stomatology, Zhejiang University School of Medicine and Key Laboratory of Oral Biomedical Research of Zhejiang Province, Hangzhou 310006, China
| | - Zhan Zhang
- Department of Orthopedics, Tongde Hospital of Zhejiang Province, Hangzhou 310012, China
| | - Biao Jin
- Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Shuqin Jiang
- Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou 310027, China
| | - Haihua Pan
- Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou 310027, China
| | - Ruikang Tang
- Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - James J De Yoreo
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Xiang Yang Liu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
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5
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Squire JM, Knupp C. Analysis methods and quality criteria for investigating muscle physiology using x-ray diffraction. J Gen Physiol 2021; 153:212538. [PMID: 34351359 PMCID: PMC8348228 DOI: 10.1085/jgp.202012778] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/23/2020] [Accepted: 07/12/2021] [Indexed: 12/20/2022] Open
Abstract
X-ray diffraction studies of muscle have been tremendously powerful in providing fundamental insights into the structures of, for example, the myosin and actin filaments in a variety of muscles and the physiology of the cross-bridge mechanism during the contractile cycle. However, interpretation of x-ray diffraction patterns is far from trivial, and if modeling of the observed diffraction intensities is required it needs to be performed carefully with full knowledge of the possible pitfalls. Here, we discuss (1) how x-ray diffraction can be used as a tool to monitor various specific muscle properties and (2) how to get the most out of the rest of the observed muscle x-ray diffraction patterns by modeling where the reliability of the modeling conclusions can be objectively tested. In other x-ray diffraction methods, such as protein crystallography, the reliability of every step of the process is estimated and quoted in published papers. In this way, the quality of the structure determination can be properly assessed. To be honest with ourselves in the muscle field, we need to do as near to the same as we can, within the limitations of the techniques that we are using. We discuss how this can be done. We also use test cases to reveal the dos and don’ts of using x-ray diffraction to study muscle physiology.
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Affiliation(s)
- John M Squire
- Muscle Contraction Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK.,Faculty of Medicine, Imperial College, London, UK
| | - Carlo Knupp
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
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6
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Roig-Solvas B, Brooks DH, Makowski L. FiXR: a framework to reconstruct fiber cross-sections from X-ray fiber diffraction experiments. Acta Crystallogr D Struct Biol 2020; 76:102-117. [DOI: 10.1107/s2059798319015961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 11/26/2019] [Indexed: 11/10/2022] Open
Abstract
Ab initio reconstruction methods have revolutionized the capabilities of small-angle X-ray scattering (SAXS), allowing the data-driven discovery of previously unknown molecular conformations, exploiting optimization heuristics and assumptions behind the composition of globular molecules. While these methods have been successful for the analysis of small particles, their impact on fibrillar assemblies has been more limited. The micrometre-range size of these assemblies and the complex interaction of their periodicities in their scattering profiles indicate that the discovery of fibril structures from SAXS measurements requires novel approaches beyond extending existing tools for molecular discovery. In this work, it is proposed to use SAXS measurements, together with diffraction theory, to infer the electron distribution of the average cross-section of a fiber. This cross-section is modeled as a discrete electron density with continuous support, allowing representations beyond binary distributions. Additional constraints, such as non-negativity or smoothness/connectedness, can also be added to the framework. The proposed approach is tested using simulated SAXS data from amyloid β fibril models and using measured data of Tobacco mosaic virus from SAXS experiments, recovering the geometry and density of the cross-sections in all cases. The approach is further tested by analyzing SAXS data from different amyloid β fibril assemblies, with results that are in agreement with previously proposed models from cryo-EM measurements. The limitations of the proposed method, together with an analysis of the robustness of the method and the combination with different experimental sources, are also discussed.
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7
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Eakins F, Knupp C, Squire JM. Monitoring the myosin crossbridge cycle in contracting muscle: steps towards 'Muscle-the Movie'. J Muscle Res Cell Motil 2019; 40:77-91. [PMID: 31327096 PMCID: PMC6726672 DOI: 10.1007/s10974-019-09543-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 07/10/2019] [Indexed: 11/20/2022]
Abstract
Some vertebrate muscles (e.g. those in bony fish) have a simple lattice A-band which is so well ordered that low-angle X-ray diffraction patterns are sampled in a simple way amenable to crystallographic techniques. Time-resolved X-ray diffraction through the contractile cycle should provide a movie of the molecular movements involved in muscle contraction. Generation of 'Muscle-The Movie' was suggested in the 1990s and since then efforts have been made to work out how to achieve it. Here we discuss how a movie can be generated, we discuss the problems and opportunities, and present some new observations. Low angle X-ray diffraction patterns from bony fish muscles show myosin layer lines that are well sampled on row-lines expected from the simple hexagonal A-band lattice. The 1st, 2nd and 3rd myosin layer lines at d-spacings of around 42.9 nm, 21.5 nm and 14.3 nm respectively, get weaker in patterns from active muscle, but there is a well-sampled intensity remnant along the layer lines. We show here that the pattern from the tetanus plateau is not a residual resting pattern from fibres that have not been fully activated, but is a different well-sampled pattern showing the presence of a second, myosin-centred, arrangement of crossbridges within the active crossbridge population. We also show that the meridional M3 peak from active muscle has two components of different radial widths consistent with (i) active myosin-centred (probably weak-binding) heads giving a narrow peak and (ii) heads on actin in strong states giving a broad peak.
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Affiliation(s)
- Felicity Eakins
- Faculty of Medicine, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
| | - Carlo Knupp
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF10 3NB, UK
| | - John M Squire
- Faculty of Medicine, Imperial College London, Exhibition Road, London, SW7 2AZ, UK.
- Muscle Contraction Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK.
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8
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Different Myosin Head Conformations in Bony Fish Muscles Put into Rigor at Different Sarcomere Lengths. Int J Mol Sci 2018; 19:ijms19072091. [PMID: 30022010 PMCID: PMC6073893 DOI: 10.3390/ijms19072091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 07/13/2018] [Accepted: 07/14/2018] [Indexed: 12/26/2022] Open
Abstract
At a resting sarcomere length of approximately 2.2 µm bony fish muscles put into rigor in the presence of BDM (2,3-butanedione monoxime) to reduce rigor tension generation show the normal arrangement of myosin head interactions with actin filaments as monitored by low-angle X-ray diffraction. However, if the muscles are put into rigor using the same protocol but stretched to 2.5 µm sarcomere length, a markedly different structure is observed. The X-ray diffraction pattern is not just a weaker version of the pattern at full overlap, as might be expected, but it is quite different. It is compatible with the actin-attached myosin heads being in a different conformation on actin, with the average centre of cross-bridge mass at a higher radius than in normal rigor and the myosin lever arms conforming less to the actin filament geometry, probably pointing back to their origins on their parent myosin filaments. The possible nature of this new rigor cross-bridge conformation is discussed in terms of other well-known states such as the weak binding state and the 'roll and lock' mechanism; we speculate that we may have trapped most myosin heads in an early attached strong actin-binding state in the cross-bridge cycle on actin.
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9
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Fibre diffraction studies of biological macromolecules. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 127:43-87. [DOI: 10.1016/j.pbiomolbio.2017.04.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 03/21/2017] [Accepted: 04/05/2017] [Indexed: 12/27/2022]
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10
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Abass A, Bell JS, Spang MT, Hayes S, Meek KM, Boote C. SAXS4COLL: an integrated software tool for analysing fibrous collagen-based tissues. J Appl Crystallogr 2017; 50:1235-1240. [PMID: 28808439 PMCID: PMC5541358 DOI: 10.1107/s1600576717007877] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 05/26/2017] [Indexed: 12/02/2022] Open
Abstract
SAXS4COLL is an interactive computer program for reduction and analysis of small-angle X-ray scattering data from fibrous collagen tissues, combining data reduction, bespoke background subtraction, semi-automated peak detection and calibration. This article provides an overview of a new integrated software tool for reduction and analysis of small-angle X-ray scattering (SAXS) data from fibrous collagen tissues, with some wider applicability to other cylindrically symmetric scattering systems. SAXS4COLL combines interactive features for data pre-processing, bespoke background subtraction, semi-automated peak detection and calibration. Both equatorial and meridional SAXS peak parameters can be measured, and the former can be deconstructed into cylinder and lattice contributions. Finally, the software combines functionality for determination of collagen spatial order parameters with a rudimentary orientation plot capability.
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Affiliation(s)
- Ahmed Abass
- Structural Biophysics Group, School of Optometry and Vision Science, Cardiff University, Maindy Road, Cardiff CF24 4HQ, UK
| | - James S Bell
- Structural Biophysics Group, School of Optometry and Vision Science, Cardiff University, Maindy Road, Cardiff CF24 4HQ, UK
| | - Martin T Spang
- Structural Biophysics Group, School of Optometry and Vision Science, Cardiff University, Maindy Road, Cardiff CF24 4HQ, UK
| | - Sally Hayes
- Structural Biophysics Group, School of Optometry and Vision Science, Cardiff University, Maindy Road, Cardiff CF24 4HQ, UK
| | - Keith M Meek
- Structural Biophysics Group, School of Optometry and Vision Science, Cardiff University, Maindy Road, Cardiff CF24 4HQ, UK
| | - Craig Boote
- Structural Biophysics Group, School of Optometry and Vision Science, Cardiff University, Maindy Road, Cardiff CF24 4HQ, UK
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11
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Abstract
In the last decade, improvements in electron microscopy and image processing have permitted significantly higher resolutions to be achieved (sometimes <1 nm) when studying isolated actin and myosin filaments. In the case of actin filaments the changing structure when troponin binds calcium ions can be followed using electron microscopy and single particle analysis to reveal what happens on each of the seven non-equivalent pseudo-repeats of the tropomyosin α-helical coiled-coil. In the case of the known family of myosin filaments not only are the myosin head arrangements under relaxing conditions being defined, but the latest analysis, also using single particle methods, is starting to reveal the way that the α-helical coiled-coil myosin rods are packed to give the filament backbones.
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Affiliation(s)
- John M Squire
- Muscle Contraction Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK.
| | - Danielle M Paul
- Muscle Contraction Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK
| | - Edward P Morris
- Division of Structural Biology, The Institute of Cancer Research, London, SW3 6JB, UK
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12
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Eakins F, Pinali C, Gleeson A, Knupp C, Squire JM. X-ray Diffraction Evidence for Low Force Actin-Attached and Rigor-Like Cross-Bridges in the Contractile Cycle. BIOLOGY 2016; 5:E41. [PMID: 27792170 PMCID: PMC5192421 DOI: 10.3390/biology5040041] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/01/2016] [Accepted: 10/10/2016] [Indexed: 11/17/2022]
Abstract
Defining the structural changes involved in the myosin cross-bridge cycle on actin in active muscle by X-ray diffraction will involve recording of the whole two dimensional (2D) X-ray diffraction pattern from active muscle in a time-resolved manner. Bony fish muscle is the most highly ordered vertebrate striated muscle to study. With partial sarcomere length (SL) control we show that changes in the fish muscle equatorial A-band (10) and (11) reflections, along with (10)/(11) intensity ratio and the tension, are much more rapid than without such control. Times to 50% change with SL control were 19.5 (±2.0) ms, 17.0 (±1.1) ms, 13.9 (±0.4) ms and 22.5 (±0.8) ms, respectively, compared to 25.0 (±3.4) ms, 20.5 (±2.6) ms, 15.4 (±0.6) ms and 33.8 (±0.6) ms without control. The (11) intensity and the (10)/(11) intensity ratio both still change ahead of tension, supporting the likelihood of the presence of a head population close to or on actin, but producing little or no force, in the early stages of the contractile cycle. Higher order equatorials (e.g., (30), (31), and (32)), more sensitive to crossbridge conformation and distribution, also change very rapidly and overshoot their tension plateau values by a factor of around two, well before the tension plateau has been reached, once again indicating an early low-force cross-bridge state in the contractile cycle. Modelling of these intensity changes suggests the presence of probably two different actin-attached myosin head structural states (mainly low-force attached and rigor-like). No more than two main attached structural states are necessary and sufficient to explain the observations. We find that 48% of the heads are off actin giving a resting diffraction pattern, 20% of heads are in the weak binding conformation and 32% of the heads are in the strong (rigor-like) state. The strong states account for 96% of the tension at the tetanus plateau.
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Affiliation(s)
- Felicity Eakins
- Faculty of Medicine, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
| | - Christian Pinali
- Biophysics Group, Optometry & Vision Sciences, University of Cardiff, Cardiff CF10 3XQ, UK.
| | | | - Carlo Knupp
- Faculty of Medicine, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
- Biophysics Group, Optometry & Vision Sciences, University of Cardiff, Cardiff CF10 3XQ, UK.
| | - John M Squire
- Faculty of Medicine, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
- Muscle Contraction Group, School of Physiology, Pharmacology & Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol BS8 1TH, UK.
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13
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Ferrer P, da Silva I, Puente-Orench I. Solid acetone structure dependence on pressure: a new fibre textured thin film crystallographic structure studied by grazing-incidence X-ray diffraction. CrystEngComm 2016. [DOI: 10.1039/c6ce01333c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acetone thin films were crystallized directly from its vapour phase under UHV conditions at 120 K on two different substrates and studied them using GI-XRD.
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Affiliation(s)
- P. Ferrer
- SpLine-BM25 ICMM-CSIC
- ESRF (European Synchrotron Radiation Facility)
- Grenoble, France
- Diamond Light Source
- Harwell Science and Innovation Campus
| | - I. da Silva
- SpLine-BM25 ICMM-CSIC
- ESRF (European Synchrotron Radiation Facility)
- Grenoble, France
- ISIS Facility
- Rutherford Appleton Laboratory
| | - I. Puente-Orench
- Universidad de Zaragoza
- CSIC
- Instituto de Ciencia de Materiales de Aragón
- Zaragoza, Spain
- Institut Laue-Langevin
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14
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Study on the crystallization of poly(alkylene dicarboxylate)s derived from 1,9-nonanediol and mixtures with different ratios of azelaic acid and pimelic acid units. JOURNAL OF POLYMER RESEARCH 2015. [DOI: 10.1007/s10965-015-0902-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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15
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Hydrocolloid-based nutraceutical delivery systems: Effect of counter-ions on the encapsulation and release. Food Hydrocoll 2015; 43:658-663. [PMID: 25419030 DOI: 10.1016/j.foodhyd.2014.07.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Nutraceuticals provide health benefits, especially for the prevention and treatment of chronic diseases such as diabetes, obesity, cardiovascular disease and cancer. Their incorporation in food supplements, functional foods and medicinal foods is a major technological challenge due to lower water solubility, instability during processing and storage conditions. Carriers that can effectively overcome these predicaments and protect them during product development, consumption and delivery are in high demand. Toward this end, our research approach is to entrap nutraceuticals in the ordered networks of hydrocolloids. We have examined the effect cations in regulating the encapsulated amounts and release characteristics. Iota-carrageenan and eugenol have been chosen as models of hydrocolloid and nutraceutical, respectively, in the presence of Na and Ca ions. The results suggest that carrageenan maintains its network organization even after encapsulating the eugenol molecules. Increased eugenol amounts are found in the Na carrageenan complex compared to the Ca complex, and the release rate is faster from the former but it is more controlled from the latter. These differences highlight the vital role of cations on the encapsulation efficiency and release profiles of hydrocolloid-based nutraceutical carriers. The outcome offers an elegant opportunity for developing novel and value-added food systems employing low-in-cost, nontoxic and heavily consumed food grade hydrocolloids.
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Janaswamy S, Gill KL, Campanella OH, Pinal R. Organized polysaccharide fibers as stable drug carriers. Carbohydr Polym 2013; 94:209-15. [PMID: 23544530 DOI: 10.1016/j.carbpol.2013.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 01/04/2013] [Accepted: 01/05/2013] [Indexed: 10/27/2022]
Abstract
Many challenges arise during the development of new drug carrier systems, and paramount among them are safety, solubility and controlled release requirements. Although synthetic polymers are effective, the possibility of side effects imposes restrictions on their acceptable use and dose limits. Thus, a new drug carrier system that is safe to handle and free from side effects is very much in need and food grade polysaccharides stand tall as worthy alternatives. Herein, we demonstrate for the first time the feasibility of sodium iota-carrageenan fibers and their distinctive water pockets to embed and release a wide variety of drug molecules. Structural analysis has revealed the existence of crystalline network in the fibers even after encapsulating the drug molecules, and iota-carrageenan maintains its characteristic and reproducible double helical structure suggesting that the composites thus produced are reminiscent of cocrystals. The melting properties of iota-carrageenan:drug complexes are distinctly different from those of either drug or iota-carrageenan fiber. The encapsulated drugs are released in a sustained manner from the fiber matrix. Overall, our research provides an elegant opportunity for developing effective drug carriers with stable network toward enhancing and/or controlling bioavailability and extending shelf-life of drug molecules using GRAS excipients, food polysaccharides, that are inexpensive and non-toxic.
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Affiliation(s)
- Srinivas Janaswamy
- Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West Lafayette, IN 47907, USA.
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17
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Patel BK, Campanella OH, Janaswamy S. Impact of urea on the three-dimensional structure, viscoelastic and thermal behavior of iota-carrageenan. Carbohydr Polym 2012; 92:1873-9. [PMID: 23399231 DOI: 10.1016/j.carbpol.2012.11.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 10/19/2012] [Accepted: 11/08/2012] [Indexed: 11/17/2022]
Abstract
Urea breaks hydrogen bonds among biopolymers leading to structural destabilization. In the case of hydrocolloids urea addition is thought to impact gelation. Detailed information about its pertinent role on influencing the structure-function relationships of hydrocolloids is still elusive, however. The present investigation is aimed at delineating hydrocolloids structural behavior in the presence of urea employing iota-carrageenan as a model system. X-ray fiber diffraction, rheological and thermal properties of two iota-carrageenan solutions with weight concentrations 4.5 and 6.0% (w/w) at two urea molar concentrations (0.5 and 2.0 M) with and without heat treatments have been analyzed. X-ray results suggest that the canonical double helical structural arrangement of iota-carrageenan is maintained even after urea addition. However, improved crystallinity, ordering and altered unit cell dimensions especially with heat treatments of the binary mixtures indicate the promotion of favorable interactions among carrageenan helices in the presence of urea. Increased elastic modulus and onset temperature of melting endotherm with the heat treatment compared to cold addition further attests the X-ray observations of enhanced structural ordering. Overall, results suggest that urea molecules synergistically aid iota-carrageenan interactions and stabilize structure of junction zones. Our findings are deemed to be helpful in the design and development of novel non-food applications of hydrocolloids.
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Affiliation(s)
- Bhavesh K Patel
- Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907-2093, USA
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18
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McDonald M, Box H, Bian W, Kendall A, Tycko R, Stubbs G. Fiber diffraction data indicate a hollow core for the Alzheimer's aβ 3-fold symmetric fibril. J Mol Biol 2012; 423:454-61. [PMID: 22903058 DOI: 10.1016/j.jmb.2012.08.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 07/11/2012] [Accepted: 08/09/2012] [Indexed: 10/28/2022]
Abstract
Amyloid β protein (Aβ), the principal component of the extracellular plaques found in the brains of patients with Alzheimer's disease, forms fibrils well suited to structural study by X-ray fiber diffraction. Fiber diffraction patterns from the 40-residue form Aβ(1-40) confirm a number of features of a 3-fold symmetric Aβ model from solid-state NMR (ssNMR) but suggest that the fibrils have a hollow core not present in the original ssNMR models. Diffraction patterns calculated from a revised 3-fold hollow model with a more regular β-sheet structure are in much better agreement with the observed diffraction data than patterns calculated from the original ssNMR model. Refinement of a hollow-core model against ssNMR data led to a revised ssNMR model, similar to the fiber diffraction model.
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Affiliation(s)
- Michele McDonald
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634, USA
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19
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Abstract
Nutraceuticals are important due to their inherent health benefits. However, utilization and consumption are limited by their poor water solubility and instability at normal processing and storage conditions. Herein, we propose an elegant and novel approach for the delivery of nutraceuticals in their active form using hydrocolloid matrices that are inexpensive and non-toxic with generally recognized as safe (GRAS) status. Iota-carrageenan and curcumin have been chosen as models of hydrocolloid and nutraceutical compounds, respectively. The iota-carrageenan network maintains a stable organization after encapsulating curcumin molecules, protects them from melting and then releases them in a sustained manner. These findings lay a strong foundation for developing value-added functional and medicinal foods.
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Affiliation(s)
- Srinivas Janaswamy
- Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, 745 Agriculture Mall Drive, West Lafayette, IN 47907-2009, USA.
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Abstract
This communication reports gelation of lambda-carrageenan, for the first time, in the presence of trivalent iron ions. Kappa-, iota- and lambda-carrageenans are sulfated polysaccharides used extensively in food, pharmaceutical and medical applications. Kappa- and iota-carrageenans show gelation in the presence of mono- and di-valent ions, but lambda-carrageenan yields only viscous solutions. Our results show that gelation in lambda-carrageenan indeed is possible, but with trivalent ions. X-ray fiber diffraction patterns of iron (III)-lambda-carrageenan are characteristic of highly oriented and polycrystalline fibers containing well resolved Bragg reflections. The elastic modulus (G') of the product is far greater than the loss modulus (G") indicating the thermal stability of lambda-carrageenan in the presence of iron (III) ions. This novel finding has potential to expand lambda-carrageenan's current utility beyond a viscosifying agent.
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Affiliation(s)
- Cordelia A. Running
- Whistler Center for Carbohydrate Research, Department of Food Science, 745 Agriculture Mall Drive, Purdue University, West Lafayette, IN 47907-2009, USA
| | - Ruth Falshaw
- 5 Mahana Place, Springfield, Rotorua, New Zealand
| | - Srinivas Janaswamy
- Whistler Center for Carbohydrate Research, Department of Food Science, 745 Agriculture Mall Drive, Purdue University, West Lafayette, IN 47907-2009, USA
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Nishiyama Y, Wada M, Hanson BL, Langan P. Time-resolved X-ray diffraction microprobe studies of the conversion of cellulose I to ethylenediamine-cellulose I. CELLULOSE (LONDON, ENGLAND) 2010; 17:735-745. [PMID: 22693365 PMCID: PMC3371382 DOI: 10.1007/s10570-010-9415-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Structural changes during the treatment of films of highly crystalline microfibers of Cladophora cellulose with ethylenediamine (EDA) have been studied by time-resolved X-ray microprobe diffraction methods. As EDA penetrates the sample and converts cellulose I to EDA-cellulose I, the measured profile widths of reflections reveal changes in the shapes and average dimensions of cellulose I and EDA-cellulose I crystals. The (200) direction of cellulose I is most resistant to EDA penetration, with EDA penetrating most effectively at the hydrophilic edges of the hydrogen bonded sheets of cellulose chains. Most of the cellulose chains in the initial crystals of cellulose I are incorporated into crystals of EDA-cellulose I. The size of the emerging EDA-cellulose I crystals is limited to about half of their size in cellulose I, most likely due to strains introduced by the penetration of EDA molecules. There is no evidence of any gradual structural transition from cellulose I to EDA-cellulose I involving a continuously changing intermediate phase. Rather, the results point to a rapid transition to EDA-cellulose I in regions of the microfibrils that have been penetrated by EDA.
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Affiliation(s)
- Yoshiharu Nishiyama
- Centre de Recherches sur les Macromolécules, Végétales—CNRS, Joseph Fourier University of Grenoble, BP 53, 38041 Grenoble Cedex 9, France
| | - Masahisa Wada
- Department of Biomaterials Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan. Department of Plant & Environmental New Resources, College of Life Sciences, Kyung Hee University, 1, Seocheon-dong, Giheung-ku, Yongin-si, Gyeonggi-do 446-701, Korea
| | - B. Leif Hanson
- Department of Chemistry, University of Toledo, 2801W. Bancroft, Toledo, OH 43606, USA
| | - Paul Langan
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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Antipova O, Orgel JPRO. In situ D-periodic molecular structure of type II collagen. J Biol Chem 2010; 285:7087-96. [PMID: 20056598 DOI: 10.1074/jbc.m109.060400] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Collagens are essential components of extracellular matrices in multicellular animals. Fibrillar type II collagen is the most prominent component of articular cartilage and other cartilage-like tissues such as notochord. Its in situ macromolecular and packing structures have not been fully characterized, but an understanding of these attributes may help reveal mechanisms of tissue assembly and degradation (as in osteo- and rheumatoid arthritis). In some tissues such as lamprey notochord, the collagen fibrillar organization is naturally crystalline and may be studied by x-ray diffraction. We used diffraction data from native and derivative notochord tissue samples to solve the axial, D-periodic structure of type II collagen via multiple isomorphous replacement. The electron density maps and heavy atom data revealed the conformation of the nonhelical telopeptides and the overall D-periodic structure of collagen type II in native tissues, data that were further supported by structure prediction and transmission electron microscopy. These results help to explain the observed differences in collagen type I and type II fibrillar architecture and indicate the collagen type II cross-link organization, which is crucial for fibrillogenesis. Transmission electron microscopy data show the close relationship between lamprey and mammalian collagen fibrils, even though the respective larger scale tissue architecture differs.
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Affiliation(s)
- Olga Antipova
- Center for Molecular Study of Condensed Soft Matter Centers (microCoSM), Pritzker Institute of Biomedical Science and Engineering, Chicago, Illinois 60616, USA.
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Morris K, Serpell L. From natural to designer self-assembling biopolymers, the structural characterisation of fibrous proteins & peptides using fibre diffraction. Chem Soc Rev 2010; 39:3445-53. [DOI: 10.1039/b919453n] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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