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Tobin MJ, Puskar L, Hasan J, Webb HK, Hirschmugl CJ, Nasse MJ, Gervinskas G, Juodkazis S, Watson GS, Watson JA, Crawford RJ, Ivanova EP. High-spatial-resolution mapping of superhydrophobic cicada wing surface chemistry using infrared microspectroscopy and infrared imaging at two synchrotron beamlines. JOURNAL OF SYNCHROTRON RADIATION 2013; 20:482-489. [PMID: 23592628 DOI: 10.1107/s0909049513004056] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 02/09/2013] [Indexed: 06/02/2023]
Abstract
The wings of some insects, such as cicadae, have been reported to possess a number of interesting and unusual qualities such as superhydrophobicity, anisotropic wetting and antibacterial properties. Here, the chemical composition of the wings of the Clanger cicada (Psaltoda claripennis) were characterized using infrared (IR) microspectroscopy. In addition, the data generated from two separate synchrotron IR facilities, the Australian Synchrotron Infrared Microspectroscopy beamline (AS-IRM) and the Synchrotron Radiation Center (SRC), University of Wisconsin-Madison, IRENI beamline, were analysed and compared. Characteristic peaks in the IR spectra of the wings were assigned primarily to aliphatic hydrocarbon and amide functionalities, which were considered to be an indication of the presence of waxy and proteinaceous components, respectively, in good agreement with the literature. Chemical distribution maps showed that, while the protein component was homogeneously distributed, a significant degree of heterogeneity was observed in the distribution of the waxy component, which may contribute to the self-cleaning and aerodynamic properties of the cicada wing. When comparing the data generated from the two beamlines, it was determined that the SRC IRENI beamline was capable of producing higher-spatial-resolution distribution images in a shorter time than was achievable at the AS-IRM beamline, but that spectral noise levels per pixel were considerably lower on the AS-IRM beamline, resulting in more favourable data where the detection of weak absorbances is required. The data generated by the two complementary synchrotron IR methods on the chemical composition of cicada wings will be immensely useful in understanding their unusual properties with a view to reproducing their characteristics in, for example, industry applications.
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Garderen EDV, Bambery KR, Clift M, LeBlanc GS, Martin DE, Puskar L, Starritt A, Tobin MJ, Wang D, Zhu D. Instrumentation upgrade for Top-Up operations at the Australian Synchrotron. ACTA ACUST UNITED AC 2013. [DOI: 10.1088/1742-6596/425/4/042015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Cao J, Ng ES, McNaughton D, Stanley EG, Elefanty AG, Tobin MJ, Heraud P. Fourier transform infrared microspectroscopy reveals that tissue culture conditions affect the macromolecular phenotype of human embryonic stem cells. Analyst 2013; 138:4147-60. [DOI: 10.1039/c3an00321c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Hasan J, Webb HK, Truong VK, Watson GS, Watson JA, Tobin MJ, Gervinskas G, Juodkazis S, Wang JY, Crawford RJ, Ivanova EP. Spatial variations and temporal metastability of the self-cleaning and superhydrophobic properties of damselfly wings. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012. [PMID: 23181510 DOI: 10.1021/la303560w] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Self-cleaning surfaces found in nature show great potential for application in many fields, ranging from industry to medicine. The ability for a surface to self-clean is intimately related to the wetting properties of the surface; for a surface to possess self-cleaning ability it must exhibit extremely high water contact angles and low water adhesion. While investigating the self-cleaning properties of damselfly wings, significant spatial variations in surface wettability were observed. Within an area of 100 μm × 100 μm of the wing surface the water contact angle was found to vary up to 17.8°, while remaining consistently superhydrophobic. The contributions of both surface chemistry and topography to the hydrophobicity of the wings were assessed in an effort to explain these variations. Synchrotron-sourced Fourier-transform infrared microspectroscopy revealed that some of the major components of the wing were aliphatic hydrocarbons and esters, which are attributable to epicuticular lipids. The wing topography, as determined by optical profilometry and atomic force microscopy (AFM), also showed only minor levels of heterogeneity arising from irregular ordering of surface nanostructures. The measured contact angle of a single droplet of water was also found to decrease over time as it evaporated, reaching a minimum of 107°. This is well below the threshold value for superhydrophobicity (i.e., 150°), demonstrating that when the surface is in contact with water for a prolonged period, the damselfly wings lose their superhydrophobicity and subsequently their ability to self-clean. This decrease in hydrophobicity over time can be attributed to the surface undergoing a transition from the Cassie-Baxter wettability state toward the Wenzel wettability state.
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Ivanova EP, Hasan J, Webb HK, Truong VK, Watson GS, Watson JA, Baulin VA, Pogodin S, Wang JY, Tobin MJ, Löbbe C, Crawford RJ. Natural bactericidal surfaces: mechanical rupture of Pseudomonas aeruginosa cells by cicada wings. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:2489-94. [PMID: 22674670 DOI: 10.1002/smll.201200528] [Citation(s) in RCA: 485] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Indexed: 05/22/2023]
Abstract
Natural superhydrophobic surfaces are often thought to have antibiofouling potential due to their self-cleaning properties. However, when incubated on cicada wings, Pseudomonas aeruginosa cells are not repelled; instead they are penetrated by the nanopillar arrays present on the wing surface, resulting in bacterial cell death. Cicada wings are effective antibacterial, as opposed to antibiofouling, surfaces.
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Caine S, Heraud P, Tobin MJ, McNaughton D, Bernard CC. The application of Fourier transform infrared microspectroscopy for the study of diseased central nervous system tissue. Neuroimage 2012; 59:3624-40. [DOI: 10.1016/j.neuroimage.2011.11.033] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 10/20/2011] [Accepted: 11/09/2011] [Indexed: 12/13/2022] Open
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Croxford AM, Nandakumar KS, Holmdahl R, Tobin MJ, McNaughton D, Rowley MJ. Chemical changes demonstrated in cartilage by synchrotron infrared microspectroscopy in an antibody-induced murine model of rheumatoid arthritis. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:066004. [PMID: 21721805 DOI: 10.1117/1.3585680] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Collagen antibody-induced arthritis develops in mice following passive transfer of monoclonal antibodies (mAbs) to type II collagen (CII) and is attributed to effects of proinflammatory immune complexes, but transferred mAbs may react directly and damagingly with CII. To determine whether such mAbs cause cartilage damage in vivo in the absence of inflammation, mice lacking complement factor 5 that do not develop joint inflammation were injected intravenously with two arthritogenic mAbs to CII, M2139 and CIIC1. Paws were collected at day 3, decalcified, paraffin embedded, and 5-μm sections were examined using standard histology and synchrotron Fourier-transform infrared microspectroscopy (FTIRM). None of the mice injected with mAb showed visual or histological evidence of inflammation but there were histological changes in the articular cartilage including loss of proteoglycan and altered chondrocyte morphology. Findings using FTIRM at high lateral resolution revealed loss of collagen and the appearance of a new peak at 1635 cm(-1) at the surface of the cartilage interpreted as cellular activation. Thus, we demonstrate the utility of synchrotron FTIRM for examining chemical changes in diseased cartilage at the microscopic level and establish that arthritogenic mAbs to CII do cause cartilage damage in vivo in the absence of inflammation.
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Whelan DR, Bambery KR, Heraud P, Tobin MJ, Diem M, McNaughton D, Wood BR. Monitoring the reversible B to A-like transition of DNA in eukaryotic cells using Fourier transform infrared spectroscopy. Nucleic Acids Res 2011; 39:5439-48. [PMID: 21447564 PMCID: PMC3141270 DOI: 10.1093/nar/gkr175] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The ability to detect DNA conformation in eukaryotic cells is of paramount importance in understanding how some cells retain functionality in response to environmental stress. It is anticipated that the B to A transition might play a role in resistance to DNA damage such as heat, desiccation and toxic damage. To this end, conformational detail about the molecular structure of DNA has been derived primarily from in vitro experiments on extracted or synthetic DNA. Here, we report that a B- to A-like DNA conformational change can occur in the nuclei of intact cells in response to dehydration. This transition is reversible upon rehydration in air-dried cells. By systematically monitoring the dehydration and rehydration of single and double-stranded DNA, RNA, extracted nuclei and three types of eukaryotic cells including chicken erythrocytes, mammalian lymphocytes and cancerous rodent fibroblasts using Fourier transform infrared (FTIR) spectroscopy, we unequivocally assign the important DNA conformation marker bands within these cells. We also demonstrate that by applying FTIR spectroscopy to hydrated samples, the DNA bands become sharper and more intense. This is anticipated to provide a methodology enabling differentiation of cancerous from non-cancerous cells based on the increased DNA content inherent to dysplastic and neoplastic tissue.
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St John AM, Best SP, Wang Y, Tobin MJ, Puskar L, Siegele R, Cattrall RW, Kolev SD. Micrometer-Scale 2D Mapping of the Composition and Homogeneity of Polymer Inclusion Membranes. Aust J Chem 2011. [DOI: 10.1071/ch10458] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A new method for determining variations in composition at the micrometer level of polymer inclusion membranes (PIMs) using synchrotron-based Fourier-transform infrared (FTIR) microspectrometry is described and used to investigate the relationship between PIM composition and the reproducibility of formation of optically clear, ‘homogeneous’ polymer membranes. Membranes based on Aliquat 336 and poly(vinyl chloride) (PVC), di(2-ethylhexyl) phosphoric acid and PVC, and Aliquat 336 and cellulose triacetate give highly reproducible PIMs with excellent optical properties which are chemically homogeneous on the micrometer scale. The close relationship between the spatial distribution of the extractant in the PIM and the extracted species was demonstrated by proton-induced X-ray emission microspectrometry (µ-PIXE) examination of chemically homogeneous membranes loaded with uranium. There is a high correlation between the homogeneity of the distributions of extracted uranium, polymer, and extractant, both on the surface of the PIM and over its cross-section. This approach provides a quantitative basis for the evaluation and optimization of PIMs and similar composite materials.
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Chonanant C, Jearanaikoon N, Leelayuwat C, Limpaiboon T, Tobin MJ, Jearanaikoon P, Heraud P. Characterisation of chondrogenic differentiation of human mesenchymal stem cells using synchrotron FTIR microspectroscopy. Analyst 2011; 136:2542-51. [DOI: 10.1039/c1an15182g] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Carter EA, Rayner BS, McLeod AI, Wu LE, Marshall CP, Levina A, Aitken JB, Witting PK, Lai B, Cai Z, Vogt S, Lee YC, Chen CI, Tobin MJ, Harris HH, Lay PA. Silicon nitride as a versatile growth substrate for microspectroscopic imaging and mapping of individual cells. MOLECULAR BIOSYSTEMS 2010; 6:1316-22. [DOI: 10.1039/c001499k] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Chronic obstructive pulmonary disease (COPD) is no longer considered to affect only the lungs and airways but also the rest of the body. The systemic manifestations of COPD include a number of endocrine disorders, such as those involving the pituitary, the thyroid, the gonads, the adrenals and the pancreas. The mechanisms by which COPD alters endocrine function are incompletely understood but likely involve hypoxaemia, hypercapnia, systemic inflammation and glucocorticoid administration. Altered endocrine function can worsen the clinical manifestations of COPD through several mechanisms, including decreased protein anabolism, increased protein catabolism, nonenzymatic glycosylation and activation of the rennin-angiotensin-aldosterone system. Systemic effects of endocrine disorders include abnormalities in control of breathing, decreases in respiratory and limb-muscle mass and function, worsening of respiratory mechanics, impairment of cardiac function and disorders of fluid balance. Research on endocrine manifestations of COPD embraces techniques of molecular biology, integrative physiology and controlled clinical trials. A sound understanding of the various disorders of endocrine function associated with COPD is prudent for every physician who practices pulmonary medicine.
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Heraud P, Caine S, Campanale N, Karnezis T, McNaughton D, Wood BR, Tobin MJ, Bernard CCA. Early detection of the chemical changes occurring during the induction and prevention of autoimmune-mediated demyelination detected by FT-IR imaging. Neuroimage 2009; 49:1180-9. [PMID: 19796690 DOI: 10.1016/j.neuroimage.2009.09.053] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 09/17/2009] [Accepted: 09/22/2009] [Indexed: 11/30/2022] Open
Abstract
Multiple sclerosis (MS) is an inflammatory, demyelinating and neurodegenerative disease of the central nervous system (CNS). Despite progress in understanding immunogenetic aspects of this disease, the mechanisms involved in lesion formation are unknown. To gain new insights into the neuropathology of MS, we used an innovative integration of Fourier transform infrared (FT-IR) microspectroscopy, bioinformatics, and a synchrotron light source to analyze macromolecular changes in the CNS during the course and prevention of experimental autoimmune encephalomyelitis (EAE), an animal model for MS. We report that subtle chemical and structural changes not observed by conventional histology were detected before the onset of clinical signs of EAE. Moreover, trained artificial neural networks (ANNs) could discriminate, with excellent sensitivity and specificity, pathology from surrounding tissues and the early stage of the disease progression. Notably, we show that this novel measurement platform can detect characteristic differences in biochemical composition of lesion pathology in animals partially protected against EAE by vaccination with Nogo-A, an inhibitor of neural outgrowth, demonstrating the potential for automated screening and evaluation of new therapeutic agents.
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Heraud P, Tobin MJ. The emergence of biospectroscopy in stem cell research. Stem Cell Res 2009; 3:12-4. [DOI: 10.1016/j.scr.2009.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2009] [Accepted: 04/25/2009] [Indexed: 10/20/2022] Open
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65
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Webster GT, de Villiers KA, Egan TJ, Deed S, Tilley L, Tobin MJ, Bambery KR, McNaughton D, Wood BR. Discriminating the intraerythrocytic lifecycle stages of the malaria parasite using synchrotron FT-IR microspectroscopy and an artificial neural network. Anal Chem 2009; 81:2516-24. [PMID: 19278236 DOI: 10.1021/ac802291a] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synchrotron Fourier transform infrared (FT-IR) spectra of fixed single erythrocytes infected with Plasmodium falciparum at different stages of the intraerythrocytic cycle are presented for the first time. Bands assigned to the hemozoin moiety at 1712, 1664, and 1209 cm(-1) are observed in FT-IR difference spectra between uninfected erythrocytes and infected trophozoites. These bands are also found to be important contributors in separating the trophozoite spectra from the uninfected cell spectra in principal components analysis. All stages of the intraerythrocytic lifecycle of the malarial parasite, including the ring and schizont stage, can be differentiated by visual inspection of the C-H stretching region (3100-2800 cm(-1)) and by using principal components analysis. Bands at 2922, 2852, and 1738 cm(-1) assigned to the nu(asym)(CH(2) acyl chain lipids), nu(sym)(CH(2) acyl chain lipids), and the ester carbonyl band, respectively, increase as the parasite matures from its early ring stage to the trophozoite and finally to the schizont stage. Training of an artificial neural network showed that excellent automated spectroscopic discrimination between P. falciparum-infected cells and the control cells is possible. FT-IR difference spectra indicate a change in the production of unsaturated fatty acids as the parasite matures. The ring stage spectrum shows bands associated with cis unsaturated fatty acids. The schizont stage spectrum displays no evidence of cis bands and suggests an increase in saturated fatty acids. These results demonstrate that different phases of the P. falciparum intraerthyrocytic life cycle are characterized by different lipid compositions giving rise to distinct spectral profiles in the C-H stretching region. This insight paves the way for an automated infrared-based technology capable of diagnosing malaria at all intraerythrocytic stages of the parasite's life cycle.
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Wood BR, Chernenko T, Matthäus C, Diem M, Chong C, Bernhard U, Jene C, Brandli AA, McNaughton D, Tobin MJ, Trounson A, Lacham-Kaplan O. Shedding new light on the molecular architecture of oocytes using a combination of synchrotron Fourier transform-infrared and Raman spectroscopic mapping. Anal Chem 2008; 80:9065-72. [PMID: 18983174 PMCID: PMC2761072 DOI: 10.1021/ac8015483] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synchrotron Fourier transform-infrared (FT-IR) and Raman microspectroscopy were applied to investigate changes in the molecular architecture of mouse oocytes and demonstrate the overall morphology of the maturing oocyte. Here we show that differences were identified between immature mouse oocytes at the germinal vesicle (GV) and mature metaphase II (MII) stage when using this technology, without the introduction of any extrinsic markers, labels, or dyes. GV mouse oocytes were found to have a small, centrally located lipid deposit and another larger polar deposit of similar composition. MII oocytes have very large, centrally located lipid deposits. Each lipid deposit for both cell types contains an inner and outer lipid environment that differs in composition. To assess interoocyte variability, line scans were recorded across the diameter of the oocytes and compared from three independent trials (GV, n = 91; MII, n = 172), and the data were analyzed with principal component analysis (PCA). The average spectra and PCA loading plots show distinct and reproducible changes in the CH stretching region that can be used as molecular maturation markers. The method paves the way for developing an independent assay to assess oocyte status during maturation providing new insights into lipid distribution at the single cell level.
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Marshall LJR, Almond MJ, Cook SR, Pantos M, Tobin MJ, Thomas LA. Mineralised organic remains from cesspits at the Roman town of Silchester: processes and preservation. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008; 71:854-861. [PMID: 18406198 DOI: 10.1016/j.saa.2008.02.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 02/04/2008] [Accepted: 02/04/2008] [Indexed: 05/26/2023]
Abstract
Mineralised organic remains (including apple pips and cereal grains) collected during the ongoing excavations of Insula IX at the Roman town of Silchester, Hampshire have been analysed by a combination of SEM-EDX, powder XRD and IR spectroscopy. The experiments included mapping experiments using spatially resolved versions of each technique. IR and powder XRD mapping have been carried out utilising the synchrotron source at The Daresbury Laboratory on stations 11.1 and 9.6. It is concluded that these samples are preserved by rapid mineralisation in the carbonate-substituted calcium phosphate mineral, dahllite. The rapid mineralisation leads to excellent preservation of the samples and a small crystal size. The value of IR spectroscopy in studying materials like this where the crystal size is small is demonstrated. A comparison is made between the excellent preservation seen in this context and the much poorer preservation of mineralised remains seen in Context 5276 or Cesspit 5251. Comments on the possible mechanism of mineralisation of these samples are made.
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Tobin MJ, Martin-fernandez M, Jones GR. A facility for confocal imaging and microvolume fluorescence lifetime spectroscopy at the SRS. ACTA ACUST UNITED AC 2008. [DOI: 10.1080/08940889808260938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Salvadó N, Butí S, Tobin MJ, Pantos E, Prag AJNW, Pradell T. Advantages of the use of SR-FT-IR microspectroscopy: applications to cultural heritage. Anal Chem 2007; 77:3444-51. [PMID: 15924374 DOI: 10.1021/ac050126k] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Synchrotron radiation Fourier transform infrared (SR-FT-IR) microspectroscopy represents an advance over conventional FT-IR spectroscopy because it gives a higher signal/noise ratio at the highest spatial resolution due to the high brightness and collimation of synchrotron radiation. It has been successfully applied to the study of ancient paintings, alteration and corrosion layers which are heterogeneous microlayered materials made by complex mixtures of organic and inorganic compounds. Moreover, the high brightness attribute allows FT-IR spectra to be routinely obtained directly on the surfaces of the objects and opens the possibility for nondestructive testing of museum objects. We present in this paper a selection of applications of SR-FT-IR to the analysis of ancient paintings, alteration and corrosion layers where the technique has proven to be especially useful: first, the separation and identification of pigment microparticles from ancient Roman wall paintings; second, the determination of the binding media and the byproducts resulting from the interaction between binders and pigments from medieval altarpieces; and third, the study of the surface corrosion layers of a bronze helmet by means of direct analysis of the surface.
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German MJ, Pollock HM, Zhao B, Tobin MJ, Hammiche A, Bentley A, Cooper LJ, Martin FL, Fullwood NJ. Characterization of putative stem cell populations in the cornea using synchrotron infrared microspectroscopy. Invest Ophthalmol Vis Sci 2006; 47:2417-21. [PMID: 16723451 DOI: 10.1167/iovs.05-1254] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
PURPOSE High-resolution synchrotron radiation-based Fourier transform infrared (SR-FTIR) microspectroscopy coupled with multivariate analysis was used to investigate the characteristics of putative adult stem cell (SC), transiently amplified (TA) cell, and terminally differentiated (TD) cell populations of the corneal epithelium. METHODS Spectra of individual cells in situ in cryosections of bovine cornea were collected by using a synchrotron microspectroscopy facility at Daresbury Laboratory (United Kingdom). The resultant spectra were analyzed by multivariate analysis. RESULTS The median spectra of the three different cell populations showed marked differences, which correlated with their degree of differentiation and proliferative capacity. Multivariate (principal component) analysis (PCA) showed that the three cell populations could be segregated into discrete clusters, with only a slight overlap between the SC and TA cell populations. Further analysis (Mann-Whitney test) indicated that the most significant (P<0.001) spectral differences between the SC and TA cell populations were chiefly associated with changes in nucleic acid conformation. CONCLUSIONS SR-FTIR microspectroscopy coupled with PCA appears to enable the identification of SC, TA cell, and TD cell populations. The results also suggest that a small subpopulation of cells in the corneal epithelial SC niche possess TA cell-like characteristics. The most significant spectral characteristics associated with the SCs appear to relate to differences in nucleic acid conformation. This finding is consistent with recent theories suggesting that the control of differentiation is related to major changes in chromatin structure.
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O'Connor AR, Stephenson TJ, Johnson A, Tobin MJ, Ratib S, Fielder AR. Change of refractive state and eye size in children of birth weight less than 1701 g. Br J Ophthalmol 2006; 90:456-60. [PMID: 16547327 PMCID: PMC1857007 DOI: 10.1136/bjo.2005.083535] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
AIMS To determine the refractive status and ocular dimensions of a cohort of children at age 10-12 years with birth weight below 1701 g, and also the relation between the neonatal ophthalmic findings and subsequent refractive state. METHODS 293 low birthweight children who had been examined in the neonatal period were assessed at 10-12 years of age. The examination consisted of autorefraction, keratometry, and A-scan. Results of right eyes were compared with published normative data. RESULTS 293 of the birth cohort of 572 children consented to participate. The average mean spherical equivalent (MSE) in the low birthweight cohort was +0.691 dioptre, significantly higher than the control data (+0.30D, p = 0.02). The average change in MSE over the 10-12 year period was -1.00 dioptre (n = 256), but only 62.1% of cases showed a shift in refractive error of the appropriate magnitude and direction. The presence of any retinopathy of prematurity (ROP) increases the risk of developing anisometropia sixfold. CONCLUSIONS Low birth weight and ROP both significantly impact the refractive state in the long term. At age 10-12 years children born preterm have an increased prevalence of all refractive errors. In low birthweight children refractive state is relatively stable over the first decade of life with a shift towards myopia of 1 dioptre.
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German MJ, Hammiche A, Ragavan N, Tobin MJ, Cooper LJ, Matanhelia SS, Hindley AC, Nicholson CM, Fullwood NJ, Pollock HM, Martin FL. Infrared spectroscopy with multivariate analysis potentially facilitates the segregation of different types of prostate cell. Biophys J 2006; 90:3783-95. [PMID: 16500983 PMCID: PMC1440759 DOI: 10.1529/biophysj.105.077255] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The prostate gland is conventionally divided into zones or regions. This morphology is of clinical significance as prostate cancer (CaP) occurs mainly in the peripheral zone (PZ). We obtained tissue sets consisting of paraffin-embedded blocks of cancer-free transition zone (TZ) and PZ and adjacent CaP from patients (n = 6) who had undergone radical retropubic prostatectomy; a seventh tissue set of snap-frozen PZ and TZ was obtained from a CaP-free gland removed after radical cystoprostatectomy. Paraffin-embedded tissue slices were sectioned (10-mum thick) and mounted on suitable windows to facilitate infrared (IR) spectra acquisition before being dewaxed and air dried; cryosections were dessicated on BaF(2) windows. Spectra were collected employing synchrotron Fourier-transform infrared (FTIR) microspectroscopy in transmission mode or attenuated total reflection-FTIR (ATR) spectroscopy. Epithelial cell and stromal IR spectra were subjected to principal component analysis to determine whether wavenumber-absorbance relationships expressed as single points in "hyperspace" might on the basis of multivariate distance reveal biophysical differences between cells in situ in different tissue regions. After spectroscopic analysis, plotted clusters and their loadings curves highlighted marked variation in the spectral region containing DNA/RNA bands ( approximately 1490-1000 cm(-1)). By interrogating the intrinsic dimensionality of IR spectra in this small cohort sample, we found that TZ epithelial cells appeared to align more closely with those of CaP while exhibiting marked structural differences compared to PZ epithelium. IR spectra of PZ stroma also suggested that these cells are structurally more different to CaP than those located in the TZ. Because the PZ exhibits a higher occurrence of CaP, other factors (e.g., hormone exposure) may modulate the growth kinetics of initiated epithelial cells in this region. The results of this pilot study surprisingly indicate that TZ epithelial cells are more likely to exhibit what may be a susceptibility-to-adenocarcinoma spectral signature. Thus, IR spectroscopy on its own may not be sufficient to identify premalignant prostate epithelial cells most likely to progress to CaP.
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Heraud P, Wood BR, Tobin MJ, Beardall J, McNaughton D. Mapping of nutrient-induced biochemical changes in living algal cells using synchrotron infrared microspectroscopy. FEMS Microbiol Lett 2005; 249:219-25. [PMID: 16006070 DOI: 10.1016/j.femsle.2005.06.021] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 05/24/2005] [Accepted: 06/02/2005] [Indexed: 10/25/2022] Open
Abstract
High quality Fourier transform infrared (FTIR) spectra were acquired from living Micrasterias hardyi cells maintained in an IR transparent flow-through cell using a FTIR microscope coupled to a synchrotron light source. Spectral maps of living, nutrient-replete cells showed band intensities consistent with the known location of the nucleus and the chloroplasts. These were very similar to maps acquired from fixed, air-dried cells. Bands due to lipids were lowest in absorbance in the region of the nucleus and highest in the chloroplast region and this trend was reversed for the absorbance of bands attributed to protein. Spectra acquired in 10 microm steps across living phosphorus-starved (P-starved) cells, repeated approximately every 30 min, were consistent over time, and bands correlated well with the known position of the nucleus and the observed chloroplasts, corroborating the observations with replete cells. Experiments in which missing nutrients were re-supplied to starved cells showed that cells could be maintained in a functional state in the flow-through cell for up to one day. Nitrogen-starved cells re-supplied with N showed an increase in lipid in all positions measured across the cell over a 23 h period of re-supply, with the largest increases occurring in positions where the chloroplasts were observed. Re-supply of phosphorus to P-starved cells produced no changes in bands attributable to lipid or protein. Due to their thin cell body ( approximately 12 microm) and large diameter ( approximately 300 microm) Micrasterias sp. make an ideal spectroscopic model to study nutrient kinetics in algal cells.
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Martin-Fernandez M, Longshaw SV, Kirby I, Santis G, Tobin MJ, Clarke DT, Jones GR. Adenovirus type-5 entry and disassembly followed in living cells by FRET, fluorescence anisotropy, and FLIM. Biophys J 2005; 87:1316-27. [PMID: 15298934 PMCID: PMC1304470 DOI: 10.1529/biophysj.103.035444] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
We have used fluorescence resonance energy transfer (FRET) to follow the process of capsid disassembly for adenovirus (Ad) serotype 5 (Ad5) in living CHO-CAR cells. Ad5 were weakly labeled on their capsid proteins with FRET donor and acceptor fluorophores. A progressive decrease in FRET efficiency recorded during Ad5 uptake revealed that the time course of Ad5 capsid disassembly has two sequential protein dissociation rates with half-times of 3 and 60 min. Fluorescence anisotropy measurements of the segmental motions of fluorophores on Ad5 indicate that the first rate is linked to the detachment from the capsid of the protruding, flexible fiber proteins. The second rate was shown to report on the combined dissociation of protein IX, penton base, and hexons, which form the rigid icosahedral capsid shell. Fluorescence lifetime imaging microscopy measurements using a pH-sensitive probe provided information on the pH of the microenvironment of Ad5 particles during intracellular trafficking, and confirmed that the fast fiber dissociation step occurred at the onset of endocytosis. The slower dissociation phase was shown to coincide with the escape of Ad5 from endocytic compartments into the cytosol, and its arrival at the nuclear membrane. These results demonstrate a rapid, quantitative live-cell assay for the investigation of virus-cell interactions and capsid disassembly.
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O'Connor AR, Stephenson TJ, Johnson A, Tobin MJ, Ratib S, Moseley M, Fielder AR. Visual function in low birthweight children. Br J Ophthalmol 2004; 88:1149-53. [PMID: 15317706 PMCID: PMC1772308 DOI: 10.1136/bjo.2003.035154] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To determine the visual functions, at age 10-12 years, of a geographically based cohort of children of birth weight less than 1701 g. The results were compared to a group of children born at full term. METHODS 572 low birthweight (LBW) "low birthweight cohort" children who had been examined in the neonatal period were invited for review at 10-12 years of age. 169 11 year old schoolchildren born at full term were also recruited, "school cohort." Visual acuity (at distance and near), contrast sensitivity, colour vision, and visual fields were measured. RESULTS 293 of the original 572 participants consented to a further examination. Compared to the school cohort of children born at term the low birthweight cohort showed significantly lower near and distance acuities and contrast sensitivity (p<0.001 for all uniocular and binocular measures). Retinopathy of prematurity (ROP) was a very poor predictor of outcome and multivariate analysis did not identify any key neonatal factors as predictors of long term visual outcome. CONCLUSIONS Low birthweight children have a small but statistically significant deficit in both visual acuity and contrast sensitivity. Low birth weight and ROP both impact on long term visual functions.
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