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Dos Santos IFS, Edwards HGM, de Faria DLA. Hematite colour revisited: Particle size and electronic transitions. Spectrochim Acta A Mol Biomol Spectrosc 2023; 310:123810. [PMID: 38232630 DOI: 10.1016/j.saa.2023.123810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/13/2023] [Accepted: 12/22/2023] [Indexed: 01/19/2024]
Abstract
Hematite has been used as a pigment since ancient times, due to its natural abundance and colour that ranges from vivid red to purple. Caput mortuum is a purple α-Fe2O3 whose colour has been ascribed as originating from particle size. In this work, submicrometric synthetic, natural and commercial hematites were investigated by diffuse reflectance spectroscopy (DRS), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and Raman microscopy aiming to clarify the origin of the purple colour. From the results it was concluded that the purple colour is associated with crystallinity, that promotes a significant decrease in absorption below 500 nm and, simultaneously, an increase in the 6A1(6S) → 4T1(4G) d-d transition at ca. 880 nm. The behaviour of the ca. 880 nm band can be explained by the more extensive magnetic interaction between adjacent Fe3+ ions in crystalline samples but cannot explain the spectral behaviour in the green-blue region considering only the d-d transitions. A plausible explanation is that in the distorted FeO6 octahedra, both the Fe-O distances and the Fe-O-Fe angles area are affected, thus interfering in the low energy oxygen-to-iron charge transfer transition, whose tail span the 400 nm - 500 nm region and is more intense than the d-d transitions in hematite nanoparticles, nanofilms and defective (red) Fe2O3 samples. The decrease in the intensity of the charge transfer band as a consequence of the FeO6 octahedral distortion is yet to be confirmed by further experiments, but the experimental results clearly show that the purple colour of hematite is due to a decrease in optical absorption below 500 nm.
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Affiliation(s)
- Isabela F S Dos Santos
- Paulista Museum, University of São Paulo, 04263-000 São Paulo - SP, Brazil; Institute of Chemistry, University of São Paulo, 05508-000 São Paulo - SP, Brazil.
| | - Howell G M Edwards
- School of Chemistry and Biosciences, Faculty of Life Sciences, University of Bradford, Bradford, BD7 1DP, UK
| | - Dalva L A de Faria
- Institute of Chemistry, University of São Paulo, 05508-000 São Paulo - SP, Brazil; Museum of Archeology and Ethnology, Interunit Postgraduate Program in Museology (PPGMus), University of São Paulo, 05508-970 São Paulo - SP, Brazil
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2
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G M Edwards H, Jehlička J, Němečková K, Culka A. Scytonin in gypsum endolithic colonisation: First Raman spectroscopic detection of a new spectral biosignature for terrestrial astrobiological analogues and for exobiological mission database extension. Spectrochim Acta A Mol Biomol Spectrosc 2023; 292:122406. [PMID: 36738580 DOI: 10.1016/j.saa.2023.122406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/13/2023] [Accepted: 01/22/2023] [Indexed: 06/18/2023]
Abstract
Microbial colonisations of gypsum from Eastern Poland (Badenian, Middle Miocene age) were investigated by Raman microspectrometry with a rarely used excitation 445 nm excitation. Zones of microbial colonisation in selenitic gypsum endolithic outcrops comprise algae and cyanobacteria, which commonly contain the photosynthetic and protective pigments carotenoids, scytonemin and gloeocapsin. Diagnostic bands differing from those of scytonemin have been identified in black colonies in gypsum outcrops at Chotel Czierwony (Poland). Raman spectral signatures of scytonin are reported here for the first time in two endolithic specimens identified by the band wavenumbers predicted from DFT calculations. The strong or medium strong intensity Raman bands observed at 1603, 1585, 1559, 1435, and 1424 cm-1. Other weaker bands were located at 1676 (sh), 1660 (sh), 1649, 1399, 1362, 1342, 1320, 1294, 1272, 1259, and 1052 cm-1. The first observation of the Raman spectrum of scytonin in the cyanobacterial colonisation of gypsum facilitates the inclusion of this new biomolecular signature in the library of unique Raman spectra of biological pigments invaluable for detection of traces of life in frame of the planetary missions.
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Affiliation(s)
- Howell G M Edwards
- Centre for Astrobiology and Extremophiles Research, Faculty of Life Sciences, University of Bradford, Bradford BD7 1DP, UK
| | - Jan Jehlička
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, 128 43 Prague, Czech Republic
| | - Kateřina Němečková
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, 128 43 Prague, Czech Republic
| | - Adam Culka
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, 128 43 Prague, Czech Republic.
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3
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Dias Santos J, Pinto PF, Edwards HGM, Cappa de Oliveira LF. Characterization by Raman and infrared spectroscopy and fluorescence microscopy of human hair treated with cosmetic products. Spectrochim Acta A Mol Biomol Spectrosc 2022; 280:121577. [PMID: 35792483 DOI: 10.1016/j.saa.2022.121577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Analytical studies on hair structures have evolved significantly over the years and vibrational spectroscopic techniques, such as Raman and infrared, have been increasingly used for such purposes. Nowadays, there is a need to understand more and more about the action of cosmetics on the hair fiber, so this work aims to analyze the permeation of cosmetic treatments into the hair. For the molecular structural characterization, Raman and infrared spectroscopy techniques were used, being verified the efficiency in the analysis of hair samples, demonstrating the internal characteristics of the fiber and the permeation of different cosmetics. Four cosmetics were chosen for this study and, due to the techniques used, it was possible to observe the diffusion of these products inside the bleached hair. It was observed with the Raman vibrational spectroscopy that the concentration of the products is found mainly in the cuticular region, decreasing the permeate content when approaching the central region, and the infrared spectroscopy showed results compatible with the Raman spectroscopy. Therefore, vibrational spectroscopy proved to be a valuable tool for the study of cosmetic permeation into the hair fiber and for the analysis of its external and internal structure.
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Affiliation(s)
- Jordana Dias Santos
- Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, Juiz de Fora 36036-900, MG, Brazil
| | - Priscila F Pinto
- Departamento de Bioquímica, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora, Juiz de Fora 36036-900, MG, Brazil
| | - Howell G M Edwards
- School of Chemistry and Biosciences, Faculty of Life Sciences, University of Bradford, Bradford, West Yorkshire BD7 1DP, United Kingdom
| | - Luiz F Cappa de Oliveira
- Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, Juiz de Fora 36036-900, MG, Brazil.
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4
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Edwards HGM, Jay WH. English delftware (c. 1770) from Bristol, Lancaster and Liverpool: A composition study using Raman spectroscopy and electron microscopy. Spectrochim Acta A Mol Biomol Spectrosc 2022; 279:121458. [PMID: 35687989 DOI: 10.1016/j.saa.2022.121458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 05/28/2022] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
Nine decorated lead-tin glazed earthenwares, colloquially termed 'delftware', produced in c. 1770 in Bristol, Lancaster and Liverpool, England, have been analysed non-invasively by Raman spectroscopy and electron microscopy. The body paste used to manufacture these west coast wares was attained by the blending of highly dolomitic [CaMg(CO3)2] "blue" clay sourced from Carrickfergus, County Antrim, Ireland, with locally sourced clays. Thus, the resulting body fabric of these wares contains significant MgO enabling them to be differentiated from MgO-free London manufactured delftware. The glazes employed all contain arsenic, obtained as a cobalt impurity or by deliberate addition. The presence of this unvolatilised arsenic in the glaze has then reacted with the lead during firing at temperatures approaching 1000 °C and then further reacted with calcium and magnesium to form needle-like crystals of lead arsenates in the form of mimetite [Pb5(AsO4)(Cl,OH)], schulténite [Pb(AsO3OH)], β-roselite [Ca2Co(AsO4)2·2H2O], hedyphane [Ca2Pb3(AsO4)3Cl], wendwilsonite [Ca2Mg(AsO4)2·2H2O] and/or adelite [CaMgAsO4(OH)] during high temperature firing.
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Affiliation(s)
- Howell G M Edwards
- Emeritus Professor, School of Chemistry and Biosciences, Faculty of Life Sciences, Bradford University, BD7 1DP, UK
| | - William H Jay
- Associate, Faculty of Arts, Monash University, Clayton 3800, Australia.
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Demaret L, Hutchinson IB, Ingley R, Edwards HGM, Fagel N, Compere P, Javaux EJ, Eppe G, Malherbe C. Fe-Rich Fossil Vents as Mars Analog Samples: Identification of Extinct Chimneys in Miocene Marine Sediments Using Raman Spectroscopy, X-Ray Diffraction, and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy. Astrobiology 2022; 22:1081-1098. [PMID: 35704291 DOI: 10.1089/ast.2021.0128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
On Earth, the circulation of Fe-rich fluids in hydrothermal environments leads to characteristic iron mineral deposits, reflecting the pH and redox chemical conditions of the hydrothermal system, and is often associated with chemotroph microorganisms capable of deriving energy from chemical gradients. On Mars, iron-rich hydrothermal sites are considered to be potentially important astrobiological targets for searching evidence of life during exploration missions, such as the Mars 2020 and the ExoMars 2022 missions. In this study, an extinct hydrothermal chimney from the Jaroso hydrothermal system (SE Spain), considered an interesting geodynamic and mineralogical terrestrial analog for Mars, was analyzed using Raman spectroscopy, X-ray diffraction, and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The sample consists of a fossil vent in a Miocene shallow-marine sedimentary deposit composed of a marl substrate, an iron-rich chimney pipe, and a central space filled with backfilling deposits and vent condensates. The iron crust is particularly striking due to the combined presence of molecular and morphological indications of a microbial colonization, including mineral microstructures (e.g., stalks, filaments), iron oxyhydroxide phases (altered goethite, ferrihydrite), and organic signatures (carotenoids, organopolymers). The clear identification of pigments by resonance Raman spectroscopy and the preservation of organics in association with iron oxyhydroxides by Raman microimaging demonstrate that the iron crust was indeed colonized by microbial communities. These analyses confirm that Raman spectroscopy is a powerful tool for documenting the habitability of such historical hydrothermal environments. Finally, based on the results obtained, we propose that the ancient iron-rich hydrothermal pipes should be recognized as singular terrestrial Mars analog specimens to support the preparatory work for robotic in situ exploration missions to Mars, as well as during the subsequent interpretation of data returned by those missions.
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Affiliation(s)
- Lucas Demaret
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liege, Liege, Belgium
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liege, Liege, Belgium
| | - Ian B Hutchinson
- Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
| | - Richard Ingley
- Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
| | - Howell G M Edwards
- Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
| | - Nathalie Fagel
- Laboratory Argiles, Géochimie et Environnements Sédimentaires, University of Liege, Liege, Belgium
| | - Philippe Compere
- Laboratory of Functional and Evolutionary Morphology, UR FOCUS, and Centre for Applied Research and Education in Microscopy (CAREM), University of Liege, Liege, Belgium
| | - Emmanuelle J Javaux
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liege, Liege, Belgium
| | - Gauthier Eppe
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liege, Liege, Belgium
| | - Cédric Malherbe
- Mass Spectrometry Laboratory, MolSys Research Unit, University of Liege, Liege, Belgium
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, University of Liege, Liege, Belgium
- Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
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6
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Sakr A, Tawab NA, Mahmoud A, Ghaly MF, Edwards HGM, Elbashar YH. New insights on plasters, pigments and binder in mural paintings of the Setka tomb (QH 110), Elephantine, Aswan, Upper Egypt. Spectrochim Acta A Mol Biomol Spectrosc 2021; 263:120153. [PMID: 34314968 DOI: 10.1016/j.saa.2021.120153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
Abstract
Mural paintings within the tomb of Setka, Qubbet el-Hawa, in Aswan, Upper Egypt, were investigated using a multi-disciplinary analytical approach (Stereomicroscopy, SEM-EXD and FT-IR spectroscopy). The walls of the tomb were hewn from fragile sandstone and covered by a clay plaster, overlaid by two layers of white gypsum plaster. SEM micrographs were indicative of the penetration of fungal mycelium within the pores of the gypsum plaster, forming white encrustations due to the re-precipitation of gypsum. SEM micrographs revealed that the calcification of the gypsum plaster had occurred due to its exposure to a high temperature. The EDX pattern for the white plaster gave the characteristic spectrum of gypsum, the blue pigment was Egyptian blue, the black pigment was magnetite, the white pigment was of gypsum (or anhydrite) and the yellow pigment was limonite. Finally, the FT-IR spectrum of the binder gave the characteristic features of gum Arabic.
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Affiliation(s)
- Akmal Sakr
- Conservation center, National Museum of Egyptian Civilization, Cairo, Egypt
| | - Nabil Abdel Tawab
- Conservation Department, Faculty of Archaeology, Zagazig University, Zagazig, Egypt
| | - Afaf Mahmoud
- Conservation Department, Ministry of Antiquities, Aswan Area, Aswan, Egypt
| | - Mohamed F Ghaly
- Botany and Microbiology Department, Faculty of Science, Zagazig University, Zagazig, Egypt
| | - Howell G M Edwards
- Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP, UK
| | - Y H Elbashar
- Department of Basic Science, EL Gazeera High institute for Engineering and Technology, Cairo, Egypt.
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7
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Whitaker DA, Munshi T, Scowen IJ, Edwards HGM. Development of a Surface-Enhanced Raman Spectroscopic Methodology to Detect Immobilized Organic Materials in Biogeological Contexts. Astrobiology 2021; 21:1089-1098. [PMID: 34129380 DOI: 10.1089/ast.2020.2278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The likelihood of finding intact cellular structures on the surface or in the near subsurface of the martian regolith is slim, due in part to the intense bombardment of the surface by ionizing radiation from outer space. Given that this radiation is predicted to be so intense that it would render a living cell inactive within minutes, it is logical to search for evidence of microbial life by looking for molecules produced by the breakdown of cellular matter. This "pool" of molecules, known as biomarkers, consists of a range of species with various functionalities that make them likely to interact with minerals in the martian regolith. Raman spectroscopy, a molecularly specific analysis method utilized for detecting organic biomarkers among inorganic geomaterials, suffers from low signal intensity when the concentration of organics is as low as it appears to be on the martian surface. This article describes the utility of a surface-enhanced Raman spectroscopy (SERS) method used to detect extremely low levels of biomarkers that were passively adhered to mineral surfaces in a method that represents how this interaction would take place in a natural environment on Mars. The methodology showed promise for the detection of multiple classes of biomarkers.
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Affiliation(s)
- Darren A Whitaker
- Department of Chemical and Forensic Sciences, University of Bradford, Bradford, UK
| | - Tasnim Munshi
- School of Chemistry, Joseph Banks Laboratories, University of Lincoln, Lincoln, UK
| | - Ian J Scowen
- School of Chemistry, Joseph Banks Laboratories, University of Lincoln, Lincoln, UK
| | - Howell G M Edwards
- Department of Chemical and Forensic Sciences, University of Bradford, Bradford, UK
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8
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Moroz TN, Edwards HGM, Zhmodik SM. Detection of carbonate, phosphate minerals and cyanobacteria in rock from the Tomtor deposit, Russia, by Raman spectroscopy. Spectrochim Acta A Mol Biomol Spectrosc 2021; 250:119372. [PMID: 33422877 DOI: 10.1016/j.saa.2020.119372] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 11/09/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
Samples of rock from the Tomtor Nb - REE (rare-earth elements) deposit (Russia) have been investigated by Raman micro-spectroscopy using visible 532 nm wavelength excitation. Raman spectra of different samples of this rock confirm their composition as calcites and other carbonates such as rhodochrosite, and mixed solid solution phases (Ca, Mn, Fe, Mg, Ba, Sr, REE)(CO3). An association between cyanobacteria and the apatite crystals has been noted Cyanobacteria exhibited Raman modes at 1520-1517 cm-1 located in the double bonds of the central part of the polyene chain of carotenoids. A slight shift of this mode in the apatite-containing samples are dependent upon the compositions of carotenoids, the ratio of the rare earth elements adsorbed by cyanobacteria as well as their interaction with the environment. Laser-induced photoluminescence of REE and Mn+2, obtained as an analytical artifact in the Raman spectra, has been observed in most cases with significant spectral intensity. The luminescence emission of Mn 2+, Sm3+, Eu 3+, Pr3+, Ho3+, Er 3+ in the spectra of the apatite-containing samples obtained with 532 nm excitation can be attributed both to apatite and to other mineral phases with a low concentration which contain these elemental ions. The results obtained in this study allowed us to confirm that the biogenic presence of the cyanobacterial mat had a significant impact on the formation of the unique Nb-REE Tomtor deposit.
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Affiliation(s)
- T N Moroz
- Sobolev Institute of Geology and Mineralogy SB RAS, 630090 Novosibirsk, Russia.
| | - H G M Edwards
- School of Chemistry and Biosciences, Faculty of Life Sciences, University of Bradford, Bradford BD7 1DP, West Yorkshire, United Kingdom.
| | - S M Zhmodik
- Sobolev Institute of Geology and Mineralogy SB RAS, 630090 Novosibirsk, Russia
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9
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Maia LF, De Oliveira VE, Edwards HGM, De Oliveira LFC. The Diversity of Linear Conjugated Polyenes and Colours in Nature: Raman Spectroscopy as a Diagnostic Tool. Chemphyschem 2020; 22:231-249. [PMID: 33225557 DOI: 10.1002/cphc.202000818] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 11/19/2020] [Indexed: 01/15/2023]
Abstract
This review is centered on the linear conjugated polyenes, which encompasses chromatic biomolecules, such as carotenoids, polyunsaturated aldehydes and polyolefinic fatty acids. The linear extension of the conjugated double bonds in these molecules is the main feature that determines the spectroscopic properties as light-absorbing. These classes of compounds are responsible for the yellow, orange, red and purple colors which are observed in their parent flora and fauna in nature. Raman spectroscopy has been used as analytical tool for the characterization of these molecules, mainly due to the strong light scattering produced by the delocalized pi electrons in the carbon chain. In addition, conjugated polyenes are one of the main target molecular species for astrobiology, and we also present a brief discussion of the use of Raman spectroscopy as one of the main analytical tools for the detection of polyenes extra-terrestrially.
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Affiliation(s)
- Lenize F Maia
- Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, Campus Universitário s/n - Martelos, Juiz de Fora-MG, 36033-620, Brazil
| | - Vanessa E De Oliveira
- Departamento de Ciências da Natureza, Universidade Federal Fluminense, Campus Universitário de Rio das Ostras, Rua Recife, Lotes 1-7, Jardim Bela Vista, Rio das Ostras, RJ, 28895-532, Brazil
| | - Howell G M Edwards
- School of Chemistry and Biosciences, Faculty of Life Sciences, University of Bradford, West Yorkshire, BD7 1DP, United Kingdom
| | - Luiz Fernando C De Oliveira
- Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, Campus Universitário s/n - Martelos, Juiz de Fora-MG, 36033-620, Brazil
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10
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Schotsmans EMJ, Wessling R, McClue WA, Wilson AS, Edwards HGM, Denton J. Histology and Raman spectroscopy of limed human remains from the Rwandan Genocide. J Forensic Leg Med 2020; 70:101895. [PMID: 31965971 DOI: 10.1016/j.jflm.2020.101895] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/16/2019] [Accepted: 01/05/2020] [Indexed: 11/17/2022]
Abstract
The Murambi Genocide Memorial Centre is one of the major centres in Rwanda that commemorate the 1994 Rwandan genocide. Seventeen months after the genocide, about 1000 excavated human remains were put on display in Murambi Technical School. Repeated efforts were made to desiccate the human remains with lime for educational reasons. The aim of this study was to assess their state of preservation and understand the extent of degradation of the tissue. Limed soft tissue samples from four individuals were examined with light and electron microscopy, and subjected to histological analysis. Raman spectroscopy at 785 nm and 1064 nm provided information about the impact of environmental conditions on the extent of deterioration to these samples, the presence of organics and the conversion of the associated lime from calcium hydroxide to calcium carbonate. While visual degradation of the bodies in Murambi has been reported, this study confirms deterioration at a microscopic and molecular level. Both histology and Raman spectroscopic analysis revealed that the limed bodies in Murambi were deteriorating at the time the samples were collected. The results of this study will inform future decisions regarding the long-term conservation of those human remains.
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Affiliation(s)
- Eline M J Schotsmans
- Centre for Archaeological Science, University of Wollongong, Wollongong, Australia; PACEA De la Préhistoire à l'Actuel: Culture, Environnement et Anthropologie, Université de Bordeaux-CNRS, UMR 5199, Pessac, France.
| | - Roland Wessling
- Cranfield Forensic Institute, Cranfield University, Shrivenham, SN6 8LA, United Kingdom
| | - W Alan McClue
- Forensic Science Research Group, Bournemouth University, Bournemouth, BH12 5BB, United Kingdom
| | - Andrew S Wilson
- School of Archaeological & Forensic Sciences, University of Bradford, Bradford, BD7 1DP, United Kingdom
| | - Howell G M Edwards
- School of Chemistry and Biosciences, University of Bradford, Bradford, BD7 1DP, United Kingdom
| | - John Denton
- Department of Pathological Sciences, University of Manchester, Manchester, M13 9PT, United Kingdom
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11
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Dos Santos JD, Edwards HGM, de Oliveira LFC. Raman spectroscopy and electronic microscopy structural studies of Caucasian and Afro human hair. Heliyon 2019; 5:e01582. [PMID: 31111104 PMCID: PMC6512080 DOI: 10.1016/j.heliyon.2019.e01582] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 04/05/2019] [Accepted: 04/24/2019] [Indexed: 01/09/2023] Open
Abstract
Human hair fibre is subjected to various structural modifications due to the application of chemicals such as dyes, shampoos and bleaches and/or physical procedures such as heating, and often more than one procedure is performed on the same hair. The present work aims to analyze the changes incurred in hair samples of two ethnic groups, namely Caucasian and Afro, before and after different treatments such as thermal, bleaching and straightening. In addition to observing the damage caused by each treatment separately, the study of samples that received all three treatments was carried out. For molecular structural characterization, the Raman vibrational spectroscopic technique was used and scanning electron microscopy (SEM) was used for morphological analysis of the hair fibres. This investigation has shown, through vibrational spectroscopy, that several important bonds have been modified, such as the S-S, C-S, C-C and S-O bonds as well as the secondary structures of proteins that have indergone changes in their conformation as a result of the treatment. Hair from the two ethnic groups showed small differences in relation to each applied treatment. Excessive heat generated a higher rate of Raman spectral band intensity changes when compared to the other treatments and it was observed that the action of several treatments on the same hair fibres resulted in even more pronounced structural changes. Finally, scanning electron microscopy showed that each treatment caused a different morphological deformation pattern on the capillary surface of the human hair.
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Affiliation(s)
- Jordana Dias Dos Santos
- Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, Campus Universitario s/n, Martelos, Juiz de Fora, MG, 36036-330, Brazil
| | - Howell G M Edwards
- School of Life Sciences, University of Bradford, Bradford, West Yorkshire, BD7 1DP, United Kingdom
| | - Luiz Fernando Cappa de Oliveira
- Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, Campus Universitario s/n, Martelos, Juiz de Fora, MG, 36036-330, Brazil
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12
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Malherbe C, Hutchinson IB, McHugh M, Ingley R, Jehlička J, Edwards HGM. Accurate Differentiation of Carotenoid Pigments Using Flight Representative Raman Spectrometers. Astrobiology 2017; 17:351-362. [PMID: 28418705 DOI: 10.1089/ast.2016.1547] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Raman spectrometers will be utilized on two Mars rover missions, ExoMars and Mars 2020, in the near future, to search for evidence of life and habitable geological niches on Mars. Carotenoid pigments are recognized target biomarkers, and as they are highly active in Raman spectroscopy, they can be readily used to characterize the capabilities of space representative instrumentation. As part of the preparatory work being performed for the ExoMars mission, a gypsum crust colonized by microorganisms was interrogated with commercial portable Raman instruments and a flight representative Raman laser spectrometer. Four separate layers, each exhibiting different coloration resulting from specific halophilic microorganism activities within the gypsum crust, were studied by using two excitation wavelengths: 532 and 785 nm. Raman or fluorescence data were readily obtained during the present study. Gypsum, the main constituent of the crust, was detected with both excitation wavelengths, while the resonance Raman signal associated with carotenoid pigments was only detected with a 532 nm excitation wavelength. The fluorescence originating from bacteriochlorophyll a was found to overwhelm the Raman signal for the layer colonized by sulfur bacteria when interrogated with a 785 nm excitation wavelength. Finally, it was demonstrated that portable instruments and the prototype were capable of detecting a statistically significant difference in band positions of carotenoid signals between the sample layers. Key Words: Gypsum-Raman spectrometers-Carotenoids-ExoMars-Mars exploration-Band position shift. Astrobiology 17, 351-362.
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Affiliation(s)
- Cedric Malherbe
- 1 Department of Physics, University of Leicester , UK
- 2 Laboratory of Inorganic Analytical Chemistry, Department of Chemistry, University of Liège , Belgium
| | | | | | | | - Jan Jehlička
- 3 Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague , Czech Republic
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Hibberts S, Edwards HGM, Abdel-Ghani M, Vandenabeele P. Raman spectroscopic analysis of a 'noli me tangere' painting. Philos Trans A Math Phys Eng Sci 2016; 374:rsta.2016.0044. [PMID: 27799428 DOI: 10.1098/rsta.2016.0044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/31/2016] [Indexed: 06/06/2023]
Abstract
The discovery of an oil painting in seriously damaged condition with an important historical and a heterodox detail with possible origins in the late fifteenth century has afforded the opportunity for Raman microscopic analysis prior to its restoration being undertaken. The painting depicts a risen Christ following His crucifixion in a 'noli me tangere' pose with three women in an Italian terrace garden with a stone balustrade overlooking a rural landscape and an undoubted view of late-medieval Florence. The picture has suffered much abuse and is in very poor condition, which is possibly attributable to its controversial portrayal of a polydactylic Christ with six toes on His right foot. By the late sixteenth century, after the Council of Trent, this portrayal would almost certainly have been frowned upon by the Church authorities or more controversially as a depiction of the holy. Raman spectroscopic analysis of the pigments places the painting as being consistent chronologically with the Renaissance period following the identification of cinnabar, haematite, red lead, lead white, goethite, verdigris, caput mortuum and azurite with no evidence of more modern synthetic pigments or of modern restoration having been carried out. An interesting pigment mixture found here is that of the organic dye carmine and cinnabar to produce a particular bright red pigment coloration. Stratigraphic examination of the paint fragments has demonstrated the presence of an orange resin layer immediately on top of the canvas substrate, effectively rendering the pigment as a sandwich between this substratal resin and the overlying varnish. The Raman spectroscopic evidence clearly indicates that an attribution of the artwork to the Renaissance is consistent with the scientific analysis of the pigment composition.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'.
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Affiliation(s)
- Stephen Hibberts
- Division of Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK
| | - Howell G M Edwards
- Division of Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK
| | - Mona Abdel-Ghani
- Division of Archaeological, Geographical and Environmental Sciences, School of Life Sciences, Cairo University, Giza, Egypt
- Conservation Department, Faculty of Archaeology, Cairo University, Giza, Egypt
| | - Peter Vandenabeele
- Laboratory for Archaeometry, Department of Archaeology, Faculty of Arts and Philosophy, Ghent University, Sint-Pietersnieuwstraat 35, 9000 Ghent, Belgium
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Edwards HGM, Elkin D, Maier MS. Raman spectroscopic analysis of archaeological specimens from the wreck of HMS Swift, 1770. Philos Trans A Math Phys Eng Sci 2016; 374:rsta.2016.0053. [PMID: 27799436 PMCID: PMC5095530 DOI: 10.1098/rsta.2016.0053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/06/2016] [Indexed: 06/06/2023]
Abstract
Specimens from underwater archaeological excavations have rarely been analysed by Raman spectroscopy probably due to the problems associated with the presence of water and the use of alternative techniques. The discovery of the remains of the Royal Navy warship HMS Swift off the coast of Patagonia, South America, which was wrecked in 1770 while undertaking a survey from its base in the Falkland/Malvinas Islands, has afforded the opportunity for a first-pass Raman spectroscopic study of the contents of several glass jars from a wooden chest, some of which had suffered deterioration of their contents owing to leakage through their stoppers. From the Raman spectroscopic data, it was possible to identify organic compounds such as anthraquinone and copal resin, which were empirically used as materia medica in the eighteenth century to treat shipboard diseases; it seems very likely, therefore, that the wooden chest belonged to the barber-surgeon on the ship. Spectra were obtained from the wet and desiccated samples, but several samples from containers that had leaked were found to contain only minerals, such as aragonite and sediment.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'.
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Affiliation(s)
- Howell G M Edwards
- Division of Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Bradford BD7 1DP, West Yorkshire, UK
| | - Dolores Elkin
- CONICET, Programa de Arqueologia Subacuatica, Instituto Nacional de Antropologia y Pensamiento Latinoamericano, 3 de Febrero 1378 (1426), Buenos Aires, Argentina
| | - Marta S Maier
- Universidad de Buenos Aires. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Microanálisis y Métodos Físicos Aplicados a la Química Orgánica (UMYMFOR). Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica. Pabellón 2, Ciudad Universitaria, (C1428EGA), Ciudad Autónoma de Buenos Aires, Argentina
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Carter EA, Perez FR, Garcia JM, Edwards HGM. Raman spectroscopic analysis of an important Visigothic historiated manuscript. Philos Trans A Math Phys Eng Sci 2016; 374:rsta.2016.0041. [PMID: 27799425 PMCID: PMC5095521 DOI: 10.1098/rsta.2016.0041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/02/2016] [Indexed: 06/06/2023]
Abstract
Raman spectroscopy has been used to study fragments of early Visigothic historiated manuscripts from the important mediaeval library at Santo Domingo de Silos which were a part of a Beato dating from the tenth to the mid-eleventh centuries. These fragments are from some of the oldest manuscripts in the scriptorium of the monastery. In this study, a comparison is made between the pigments and inks used on these manuscripts and those used in a previous study of the unique Visigothic Beato de Valcavado in Santa Cruz, Valladolid, completed in the year 970, which is noted for its quality of execution as well as its content and is remarkable eschatologically in being identifiable as the complete work of only a single scribe. For comparative purposes, the pigments and inks used in the Silos Monastery Beato and a series of historiated early manuscripts from mediaeval times through to the Renaissance also held in the monastic library were analysed. Raman spectroscopy identified a range of mineral and organic pigments such as cinnabar, orpiment, minium, azurite and indigo. In addition, a number of admixtures were found, for example, indigo and orpiment to produce vergaut (green) and a mixture of cinnabar with iron-gall ink and cerussite to produce darker and lighter shades of red. Some interesting conclusions were drawn about the use of iron-gall and carbon-based inks.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'.
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Affiliation(s)
- Elizabeth A Carter
- Vibrational Spectroscopy Core Facility and School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Fernando Rull Perez
- Unidad Asociada UVa-CSIC al Centro de Astrobiología, Parque Tecnológico de Boecillo, Valladolid, Spain
| | - Jesús Medina Garcia
- Division of Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK
| | - Howell G M Edwards
- Division of Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK
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Edwards HGM, Vandenabeele P. Raman spectroscopy in art and archaeology. Philos Trans A Math Phys Eng Sci 2016; 374:rsta.2016.0052. [PMID: 27799435 PMCID: PMC5095529 DOI: 10.1098/rsta.2016.0052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/09/2016] [Indexed: 06/06/2023]
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O'Connor S, Edwards HGM, Ali EMA. The preservation of archaeological brain remains in a human skeleton. Philos Trans A Math Phys Eng Sci 2016; 374:rsta.2016.0208. [PMID: 27799437 DOI: 10.1098/rsta.2016.0208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/08/2016] [Indexed: 06/06/2023]
Abstract
The identification of biomass within the cranial cavity of a waterlogged human skeleton inside a fish-tailed wooden coffin from a nineteenth century burial has been confirmed as brain tissue. A comparison is made between the Raman spectra obtained in the current study with those from an Iron Age brain found in an isolated cranium dating from about 500 years BCE, the only other Raman spectroscopy study made of human brain recovered from waterlogged, archaeological excavations. The spectra give some surprisingly detailed information about the state of preservation of brain tissue in both burials, especially when it is realized that, unlike preserved bog bodies, no other soft tissue has survived. The biosignatures of proteinaceous brain material are well characterized. The presence of spectral signatures from extraneous cyanobacterial colonization in the depositional site of the Iron Age brain had been construed to be responsible in part for the unusual preservation of brain tissues in the waterlogged environment, but they were not detected in the current study of the nineteenth century brain. The challenges for Raman spectroscopic analysis of biomaterials under these conditions are reviewed in the light of the successful outcome of the experiments.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'.
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Affiliation(s)
- Sonia O'Connor
- Department of Archaeological Sciences, School of Life Sciences, University of Bradford, Bradford BD7 1 DP, UK
| | - Howell G M Edwards
- Division of Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Bradford BD7 1 DP, UK
| | - Esam M A Ali
- Division of Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Bradford BD7 1 DP, UK
- Department of Forensic Medicine, University of Sohag, Sohag, Egypt
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Schotsmans EMJ, García-Rubio A, Edwards HGM, Munshi T, Wilson AS, Ríos L. Analyzing and Interpreting Lime Burials from the Spanish Civil War (1936-1939): A Case Study from La Carcavilla Cemetery. J Forensic Sci 2016; 62:498-510. [PMID: 27907232 DOI: 10.1111/1556-4029.13276] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 05/14/2016] [Accepted: 05/28/2016] [Indexed: 11/29/2022]
Abstract
Over 500 victims of the Spanish Civil War (1936-1939) were buried in the cemetery of La Carcavilla (Palencia, Spain). White material, observed in several burials, was analyzed with Raman spectroscopy and powder XRD, and confirmed to be lime. Archaeological findings at La Carcavilla's cemetery show that the application of lime was used in an organized way, mostly associated with coffinless interments of victims of Francoist repression. In burials with a lime cast, observations made it possible to draw conclusions regarding the presence of soft tissue at the moment of deposition, the sequence of events, and the presence of clothing and other evidence. This study illustrates the importance of analyzing a burial within the depositional environment and taphonomic context.
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Affiliation(s)
- Eline M J Schotsmans
- Laboratoire PACEA De la Préhistoire à l'Actuel: Culture, Environnement et Anthropologie UMR 5199, Université de Bordeaux, Bat. B8, Allee Geoffroy St Hilaire, CS 50023, 33615, Pessac Cedex, France.,Department of Archaeological Sciences, University of Bradford, West Yorkshire, BD7 1DP, UK
| | - Almudena García-Rubio
- Unit of Physical Anthropology, Department of Biology, Universidad Autónoma de Madrid, C/Darwin 2, Madrid, 28049, Spain.,Department of Physical Anthropology, Aranzadi Society of Sciences, Zorroagagaina 11, Donostia, Basque Country, Spain
| | - Howell G M Edwards
- Department of Chemistry, University of Bradford, West Yorkshire, BD7 1DP, UK
| | - Tasnim Munshi
- School of Chemistry, University of Lincoln, Lincoln, LN6 7DL, UK
| | - Andrew S Wilson
- Department of Archaeological Sciences, University of Bradford, West Yorkshire, BD7 1DP, UK
| | - Luis Ríos
- Department of Physical Anthropology, Aranzadi Society of Sciences, Zorroagagaina 11, Donostia, Basque Country, Spain.,Department of Paleobiology, National Museum of Natural Sciences (MNCN-CSIC), José Gutierrez Abascal 2, 28006, Madrid, Spain
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Jehlička J, Edwards HGM, Němec I, Oren A. Raman spectroscopic study of the Chromobacterium violaceum pigment violacein using multiwavelength excitation and DFT calculations. Spectrochim Acta A Mol Biomol Spectrosc 2015; 151:459-467. [PMID: 26151435 DOI: 10.1016/j.saa.2015.06.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 06/08/2015] [Accepted: 06/17/2015] [Indexed: 06/04/2023]
Abstract
Violacein is a bisindole pigment occurring as a biosynthetic product of Chromobacterium violaceum and Janthinobacterium lividum. It has some structural similarities to the cyanobacterial UV-protective pigment scytonemin, which has been the subject of comprehensive spectroscopic and structural studies. A detailed experimental Raman spectroscopic study with visible and near-infrared excitation of violacein produced by C. violaceum has been undertaken and supported using theoretical DFT calculations. Raman spectra with 514 and 785 nm excitation of cultivated cells as well as extracts and Gaussian (B3LYP/6-311++G(d,p)) calculations with proposed molecular vibrational assignments are reported here.
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Affiliation(s)
- Jan Jehlička
- Charles University in Prague, Institute of Geochemistry, Mineralogy and Mineral Resources, Albertov 6, 128 43 Prague, Czech Republic.
| | - Howell G M Edwards
- Centre for Astrobiology and Extremophiles Research, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK
| | - Ivan Němec
- Charles University in Prague, Department of Inorganic Chemistry, Hlavova 8, 128 43 Prague, Czech Republic
| | - Aharon Oren
- Department of Plant and Environmental Sciences, The Institute of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus Givat Ram, 91904 Jerusalem, Israel
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de Oliveira VE, Neves Miranda MAC, Soares MCS, Edwards HGM, de Oliveira LFC. Study of carotenoids in cyanobacteria by Raman spectroscopy. Spectrochim Acta A Mol Biomol Spectrosc 2015; 150:373-380. [PMID: 26057091 DOI: 10.1016/j.saa.2015.05.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 05/14/2015] [Accepted: 05/15/2015] [Indexed: 06/04/2023]
Abstract
Cyanobacteria have established dominant aquatic populations around the world, generally in aggressive environments and under severe stress conditions, e.g., intense solar radiation. Several marine strains make use of compounds such as the polyenic molecules for their damage protection justifying the range of colours observed for these species. The peridinin/chlorophyll-a/protein complex is an excellent example of essential structures used for self-prevention; their systems allow to them surviving under aggressive environments. In our simulations, few protective dyes are required to the initial specimen defense; this is an important data concern the synthetic priority in order to supply adequate damage protection. Raman measurements obtained with 1064 and 514.5 nm excitations for Cylindrospermopsis raciborskii and Microcystis aeruginosa strains shows bands assignable to the carotenoid peridinin. It was characterized by bands at 1940, 1650, 1515, 1449, 1185, 1155 and 1000 cm(-1) assigned to ν(C=C=C) (allenic vibration), ν(C=C/CO), ν(C=C), δ(C-H, C-18/19), δ(C-H), ν(C-C), and ρ(C-CH3), respectively. Recognition by Raman spectroscopy proved to be an important tool for preliminaries detections and characterization of polyene molecules in several algae, besides initiate an interesting discussion about their synthetic priority.
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Affiliation(s)
- Vanessa End de Oliveira
- Departamento de Ciências da Natureza, Universidade Federal Fluminense, Campus de Rio das Ostras, RJ 28890-000, Brazil.
| | | | - Maria Carolina Silva Soares
- Departamento de Engenharia Sanitária e Ambiental, Universidade Federal de Juiz de Fora, Juiz de Fora, MG 36036-900, Brazil
| | - Howell G M Edwards
- School of Life Sciences, University of Bradford, Bradford BD7 1DP, West Yorkshire, England, United Kingdom
| | - Luiz Fernando Cappa de Oliveira
- NEEM - Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, Juiz de Fora, MG 36036-900, Brazil
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Edwards HGM, Vandenabeele P, Benoy TJ. Raman spectroscopic study of "The Malatesta": a Renaissance painting? Spectrochim Acta A Mol Biomol Spectrosc 2015; 137:45-49. [PMID: 25194320 DOI: 10.1016/j.saa.2014.07.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 07/02/2014] [Accepted: 07/18/2014] [Indexed: 06/03/2023]
Abstract
Raman spectroscopic analysis of the pigments on an Italian painting described as a "Full Length Portrait of a Gentleman", known also as the "Malatesta", and attributed to the Renaissance period has established that these are consistent with the historical research provenance undertaken earlier. Evidence is found for the early 19th Century addition of chrome yellow to highlighted yellow ochre areas in comparison with a similar painting executed in 1801 by Sir Thomas Lawrence of John Kemble in the role of Hamlet, Prince of Denmark. The Raman data are novel in that no analytical studies have previously been made on this painting and reinforces the procedure whereby scientific analyses are accompanied by parallel historical research.
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Affiliation(s)
- Howell G M Edwards
- Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Bradford, West Yorkshire BD7 1DP, UK.
| | - Peter Vandenabeele
- Laboratory for Archaeometry, Department of Archaeology, Faculty of Arts and Philosophy, University of Ghent, Sint-Pietersnieuwstraat 35, B-9000 Ghent, Belgium
| | - Timothy J Benoy
- The de Brecy Trust, de Brecy House, Lower Withington, Macclesfield, Cheshire SK11 9DF, UK
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Souza NLGD, Salles TF, Brandão HM, Edwards HGM, Oliveira LFCD. Synthesis, Vibrational Spectroscopic and Thermal Properties of Oxocarbon Cross-Linked Chitosan. J BRAZIL CHEM SOC 2015. [DOI: 10.5935/0103-5053.20150090] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Varnali T, Edwards HGM. Raman spectroscopic identification of scytonemin and its derivatives as key biomarkers in stressed environments. Philos Trans A Math Phys Eng Sci 2014; 372:rsta.2014.0197. [PMID: 25368346 DOI: 10.1098/rsta.2014.0197] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Raman spectroscopy has been identified as an important first-pass analytical technique for deployment on planetary surfaces as part of a suite of instrumentation in projected remote space exploration missions to detect extant or extinct extraterrestrial life signatures. Aside from the demonstrable advantages of a non-destructive sampling procedure and an ability to record simultaneously the molecular signatures of biological, geobiological and geological components in admixture in the geological record, the interrogation and subsequent interpretation of spectroscopic data from these experiments will be critically dependent upon the recognition of key biomolecular markers indicative of life existing or having once existed in extreme habitats. A comparison made with the characteristic Raman spectral wavenumbers obtained from standards is not acceptable because of shifts that can occur in the presence of other biomolecules and their host mineral matrices. In this paper, we identify the major sources of difficulty experienced in the interpretation of spectroscopic data centring on a key family of biomarker molecules, namely scytonemin and its derivatives; the parent scytonemin has been characterized spectroscopically in cyanobacterial colonies inhabiting some of the most extreme terrestrial environments and, with the support of theoretical calculations, spectra have been predicted for the characterization of several of its derivatives which could occur in novel extraterrestrial environments. This work will form the foundation for the identification of novel biomarkers and for their Raman spectroscopic discrimination, an essential step in the interpretation of potentially complex and hitherto unknown biological radiation protectants based on the scytoneman and scytonin molecular skeletons which may exist in niche geological scenarios in the surface and subsurface of planets and their satellites in our Solar System.
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Affiliation(s)
- Tereza Varnali
- Department of Chemistry, Bogazici University, Istanbul, Turkey
| | - Howell G M Edwards
- Centre for Astrobiology and Extremophiles Research, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
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Jehlička J, Edwards HGM. Raman spectroscopy meets extremophiles on Earth and Mars: studies for successful search of life. Philos Trans A Math Phys Eng Sci 2014; 372:rsta.2014.0207. [PMID: 25368352 PMCID: PMC4223863 DOI: 10.1098/rsta.2014.0207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Affiliation(s)
- Jan Jehlička
- Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague, Albertov 6, Prague 2, Czech Republic
| | - Howell G M Edwards
- Centre for Astrobiology and Extremophiles Research, School of Life Sciences, University of Bradford, Bradford, West Yorkshire BD7 1DP, UK
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Culka A, Osterrothová K, Hutchinson I, Ingley R, McHugh M, Oren A, Edwards HGM, Jehlička J. Detection of pigments of halophilic endoliths from gypsum: Raman portable instrument and European Space Agency's prototype analysis. Philos Trans A Math Phys Eng Sci 2014; 372:20140203. [PMID: 25368354 PMCID: PMC4223862 DOI: 10.1098/rsta.2014.0203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
A prototype instrument, under development at the University of Leicester, for the future European Space Agency (ESA) ExoMars mission, was used for the analysis of microbial pigments within a stratified gypsum crust from a hypersaline saltern evaporation pond at Eilat (Israel). Additionally, the same samples were analysed using a miniaturized Raman spectrometer, featuring the same 532 nm excitation. The differences in the position of the specific bands, attributed to carotenoid pigments from different coloured layers, were minor when analysed by the ESA prototype instrument; therefore, making it difficult to distinguish among the different pigments. The portable Delta Nu Advantage instrument allowed for the discrimination of microbial carotenoids from the orange/green and purple layers. The purpose of this study was to complement previous laboratory results with new data and experience with portable or handheld Raman systems, even with a dedicated prototype Raman system for the exploration of Mars. The latter is equipped with an excitation wavelength falling within the carotenoid polyene resonance region. The ESA prototype Raman instrument detected the carotenoid pigments (biomarkers) with ease, although further detailed distinctions among them were not achieved.
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Affiliation(s)
- Adam Culka
- Institute of Geochemistry, Mineralogy, and Mineral Resources, Charles University in Prague, Prague, Czech Republic
| | - Kateřina Osterrothová
- Institute of Geochemistry, Mineralogy, and Mineral Resources, Charles University in Prague, Prague, Czech Republic
| | - Ian Hutchinson
- Department of Physics and Astronomy, University of Leicester, Leicester, UK
| | - Richard Ingley
- Department of Physics and Astronomy, University of Leicester, Leicester, UK
| | - Melissa McHugh
- Department of Physics and Astronomy, University of Leicester, Leicester, UK
| | - Aharon Oren
- Department of Plant and Environmental Sciences, The Alexander Silverman Institute of Life Sciences, The Edmond J. Safra Campus, Givat Ram, Jerusalem, Israel
| | - Howell G M Edwards
- Division of Chemical and Forensic Sciences, University of Bradford, Bradford BD7 1DP, UK
| | - Jan Jehlička
- Institute of Geochemistry, Mineralogy, and Mineral Resources, Charles University in Prague, Prague, Czech Republic
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Vítek P, Jehlička J, Edwards HGM, Hutchinson I, Ascaso C, Wierzchos J. Miniaturized Raman instrumentation detects carotenoids in Mars-analogue rocks from the Mojave and Atacama deserts. Philos Trans A Math Phys Eng Sci 2014; 372:rsta.2014.0196. [PMID: 25368344 DOI: 10.1098/rsta.2014.0196] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This study is primarily focused on proving the potential of miniaturized Raman systems to detect any biomolecular and mineral signal in natural geobiological samples that are relevant for future application of the technique within astrobiologically aimed missions on Mars. A series of evaporites of varying composition and origin from two extremely dry deserts were studied, namely Atacama and Mojave. The samples represent both dry evaporitic deposits and recent evaporitic efflorescences from hypersaline brines. The samples comprise halite and different types of sulfates and carbonates. The samples were analysed in two different ways: (i) directly as untreated rocks and (ii) as homogenized powders. Two excitation wavelengths of miniaturized Raman spectrometers were compared: 532 and 785 nm. The potential to detect carotenoids as biomarkers on Mars compared with the potential detection of carbonaceous matter using miniaturized instrumentation is discussed.
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Affiliation(s)
- P Vítek
- Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague, Albertov 6, 128 43 Prague 2, Czech Republic
| | - J Jehlička
- Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague, Albertov 6, 128 43 Prague 2, Czech Republic
| | - H G M Edwards
- Department of Physics and Astronomy, Space Sciences Research Centre, University of Leicester, Leicester LE1 7RH, UK
| | - I Hutchinson
- Department of Physics and Astronomy, Space Sciences Research Centre, University of Leicester, Leicester LE1 7RH, UK
| | - C Ascaso
- Museo Nacional de Ciencias Naturales, CSIC, c/ Serrano 115 dpdo., 28006 Madrid, Spain
| | - J Wierzchos
- Museo Nacional de Ciencias Naturales, CSIC, c/ Serrano 115 dpdo., 28006 Madrid, Spain
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Hutchinson IB, Ingley R, Edwards HGM, Harris L, McHugh M, Malherbe C, Parnell J. Raman spectroscopy on Mars: identification of geological and bio-geological signatures in Martian analogues using miniaturized Raman spectrometers. Philos Trans A Math Phys Eng Sci 2014; 372:rsta.2014.0204. [PMID: 25368350 DOI: 10.1098/rsta.2014.0204] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The first Raman spectrometers to be used for in situ analysis of planetary material will be launched as part of powerful, rover-based analytical laboratories within the next 6 years. There are a number of significant challenges associated with building spectrometers for space applications, including limited volume, power and mass budgets, the need to operate in harsh environments and the need to operate independently and intelligently for long periods of time (due to communication limitations). Here, we give an overview of the technical capabilities of the Raman instruments planned for future planetary missions and give a review of the preparatory work being pursued to ensure that such instruments are operated successfully and optimally. This includes analysis of extremophile samples containing pigments associated with biological processes, synthetic materials which incorporate biological material within a mineral matrix, planetary analogues containing low levels of reduced carbon and samples coated with desert varnish that incorporate both geo-markers and biomarkers. We discuss the scientific importance of each sample type and the challenges using portable/flight-prototype instrumentation. We also report on technical development work undertaken to enable the next generation of Raman instruments to reach higher levels of sensitivity and operational efficiency.
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Affiliation(s)
- Ian B Hutchinson
- Department of Physics and Astronomy, Space Research Centre, University of Leicester, Leicester LE1 7RH, UK
| | - Richard Ingley
- Department of Physics and Astronomy, Space Research Centre, University of Leicester, Leicester LE1 7RH, UK
| | - Howell G M Edwards
- Department of Physics and Astronomy, Space Research Centre, University of Leicester, Leicester LE1 7RH, UK
| | - Liam Harris
- Department of Physics and Astronomy, Space Research Centre, University of Leicester, Leicester LE1 7RH, UK
| | - Melissa McHugh
- Department of Physics and Astronomy, Space Research Centre, University of Leicester, Leicester LE1 7RH, UK
| | - Cedric Malherbe
- Department of Physics and Astronomy, Space Research Centre, University of Leicester, Leicester LE1 7RH, UK Department of Inorganic Analytical Chemistry, Chemistry Institute (B6c), University of Liège, 4000 Liège, Belgium
| | - J Parnell
- Department of Geology & Petroleum Geology, University of Aberdeen, King's College, Aberdeen AB24 3UE, UK
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Jehlička J, Edwards HGM, Osterrothová K, Novotná J, Nedbalová L, Kopecký J, Němec I, Oren A. Potential and limits of Raman spectroscopy for carotenoid detection in microorganisms: implications for astrobiology. Philos Trans A Math Phys Eng Sci 2014; 372:rsta.2014.0199. [PMID: 25368348 PMCID: PMC4223861 DOI: 10.1098/rsta.2014.0199] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this paper, it is demonstrated how Raman spectroscopy can be used to detect different carotenoids as possible biomarkers in various groups of microorganisms. The question which arose from previous studies concerns the level of unambiguity of discriminating carotenoids using common Raman microspectrometers. A series of laboratory-grown microorganisms of different taxonomic affiliation was investigated, such as halophilic heterotrophic bacteria, cyanobacteria, the anoxygenic phototrophs, the non-halophilic heterotrophs as well as eukaryotes (Ochrophyta, Rhodophyta and Chlorophyta). The data presented show that Raman spectroscopy is a suitable tool to assess the presence of carotenoids of these organisms in cultures. Comparison is made with the high-performance liquid chromatography approach of analysing pigments in extracts. Direct measurements on cultures provide fast and reliable identification of the pigments. Some of the carotenoids studied are proposed as tracers for halophiles, in contrast with others which can be considered as biomarkers of other genera. The limits of application of Raman spectroscopy are discussed for a few cases where the current Raman spectroscopic approach does not allow discriminating structurally very similar carotenoids. The database reported can be used for applications in geobiology and exobiology for the detection of pigment signals in natural settings.
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Affiliation(s)
- Jan Jehlička
- Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague, Albertov 6, 12843 Prague, Czech Republic
| | - Howell G M Edwards
- Centre for Astrobiology and Extremophiles Research, University of Bradford, Bradford BD7 1DP, UK
| | - Kateřina Osterrothová
- Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague, Albertov 6, 12843 Prague, Czech Republic
| | - Julie Novotná
- Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague, Albertov 6, 12843 Prague, Czech Republic
| | - Linda Nedbalová
- Department of Ecology, Charles University in Prague, Viničná 7, 12844 Prague, Czech Republic
| | - Jiří Kopecký
- Academy of Science of the Czech Republic, Institute of Microbiology, Třeboň, Czech Republic
| | - Ivan Němec
- Department of Inorganic Chemistry, Charles University in Prague, Hlavova 8, 12843 Prague, Czech Republic
| | - Aharon Oren
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat-Ram, Jerusalem 91904, Israel
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29
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Edwards HGM, Hutchinson IB, Ingley R, Jehlička J. Biomarkers and their Raman spectroscopic signatures: a spectral challenge for analytical astrobiology. Philos Trans A Math Phys Eng Sci 2014; 372:rsta.2014.0193. [PMID: 25368349 DOI: 10.1098/rsta.2014.0193] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The remote robotic exploration of extraterrestrial scenarios for evidence of biological colonization in 'search for life' missions using Raman spectroscopy is critically dependent on two major factors: firstly, the Raman spectral recognition of characteristic biochemical spectral signatures in the presence of mineral matrix features; and secondly, the positive unambiguous identification of molecular biomaterials which are indicative of extinct or extant life. Both of these factors are considered here: the most important criterion is the clear definition of which biochemicals truly represent biomarkers, whose presence in the planetary geological record from an analytical astrobiological standpoint will unambiguously be indicative of life as recognized from its remote instrumental interrogation. Also discussed in this paper are chemical compounds which are associated with living systems, including biominerals, which may not in themselves be definitive signatures of life processes and origins but whose presence provides an indicator of potential life-bearing matrices.
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Affiliation(s)
- Howell G M Edwards
- Department of Physics and Astronomy, Centre for Astrobiology and Extremophiles Research, Space Research Centre, University of Leicester, Leicester LE1 7RH, UK
| | - Ian B Hutchinson
- Department of Physics and Astronomy, Centre for Astrobiology and Extremophiles Research, Space Research Centre, University of Leicester, Leicester LE1 7RH, UK
| | - Richard Ingley
- Department of Physics and Astronomy, Centre for Astrobiology and Extremophiles Research, Space Research Centre, University of Leicester, Leicester LE1 7RH, UK
| | - Jan Jehlička
- Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague, Albertov 6, 12843 Prague, Czech Republic
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30
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Varnali T, Edwards HGM. Raman spectroscopic fingerprints of scytonemin-imine: density functional theory calculations of a novel potential biomarker. Philos Trans A Math Phys Eng Sci 2014; 372:rsta.2014.0201. [PMID: 25368353 DOI: 10.1098/rsta.2014.0201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Scytonemin-imine, a novel derivative of scytonemin, has been isolated and identified very recently and proposed to serve as a photoprotective biomarker for certain bacteria growing under intense photon flux density. This study predicts theoretically the Raman spectrum of scytonemin-imine by density functional theory calculations and provides comparison of major bands to those of scytonemin, the parent compound for which both the experimentally characterized and theoretically predicted spectra exist in the literature. It is proposed to be an addendum to the collection of our previous work on scytonamin and its derivatives to facilitate recognition of the diagnostic Raman spectral signatures for scytonemin-imine.
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Affiliation(s)
- Tereza Varnali
- Department of Chemistry, Bogazici University, Istanbul, Turkey
| | - Howell G M Edwards
- Centre for Astrobiology and Extremophiles Research, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
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Abstract
This paper draws a comparison between the 700-year-old historically reported will-o'-the-wisp phenomenon and the more recent discovery of extremophilic colonization of hostile environments; both have been observed as present in isolated, stressed environmental regions and originating from biological phenomena. However, whereas extremophilic activity can be understood in terms of a survival strategy based upon the synthesis of specific suites of protective biochemicals which are designed to control biogeologically the stressed habitats and to provide protection against the extreme environments, the analytical techniques that have proved so successful for the illumination of these survival strategies of extremophiles and which are now being miniaturized for in-field studies and for extraterrestrial exploration have not been applied to a clarification or evaluation of the phenomenon of will-o'-the-wisp. The reason is simply that the will-o'-the-wispsightings have now disappeared completely. Tantalizingly, all of the most reasonable physico-chemical and biological explanations for the will-o'-the-wisp phenomenon proved to be unsatisfactory in some respect and it is clear that, just as in the case of extremophilic colonization, will-o'-the-wisp would benefit from a modern rigorous analytical study which would produce the data from which the potentially novel biological behaviour could be characterized and which would help a better understanding to be made of our natural world.
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Affiliation(s)
- Howell G M Edwards
- Centre for Astrobiology and Extremophiles Research, Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK
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Maia LF, Ferreira GR, Costa RCC, Lucas NC, Teixeira RI, Fleury BG, Edwards HGM, de Oliveira LFC. Raman Spectroscopic Study of Antioxidant Pigments from Cup Corals Tubastraea spp. J Phys Chem A 2014; 118:3429-37. [DOI: 10.1021/jp501278w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Lenize F. Maia
- NEEM
Núcleo de Espectroscopia e Estrutura Molecular, Departamento
de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, 36036-330 Juiz
de Fora, MG, Brazil
| | - Gilson R. Ferreira
- NEEM
Núcleo de Espectroscopia e Estrutura Molecular, Departamento
de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, 36036-330 Juiz
de Fora, MG, Brazil
- Faculdade
de Ciências
Médicas e da Saúde de Juiz de Fora, Hospital Maternidade Therezinha de Jesus - SUPREMA, 36033-003 Juiz de Fora, MG, Brazil
| | - Regina C. C. Costa
- NEEM
Núcleo de Espectroscopia e Estrutura Molecular, Departamento
de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, 36036-330 Juiz
de Fora, MG, Brazil
| | - Nanci C. Lucas
- Instituto
de Química, Centro de Tecnologia, Universidade Federal do Rio de Janeiro, 21949-900 Rio de Janeiro, RJ, Brazil
| | - Rodolfo I. Teixeira
- Instituto
de Química, Centro de Tecnologia, Universidade Federal do Rio de Janeiro, 21949-900 Rio de Janeiro, RJ, Brazil
| | - Beatriz G. Fleury
- Departamento
de Ecologia, IBRAG, Universidade do Estado do Rio de Janeiro, 20559-000 Rio de Janeiro, RJ, Brazil
| | - Howell G. M. Edwards
- Centre
for Astrobiology and Extremophile Research, School of Life Sciences, University of Bradford, Bradford BD7 1DP, United Kingdom
| | - Luiz F. C. de Oliveira
- NEEM
Núcleo de Espectroscopia e Estrutura Molecular, Departamento
de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, 36036-330 Juiz
de Fora, MG, Brazil
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33
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Varnali T, Edwards HGM. Scytonin, a novel cyanobacterial photoprotective pigment: calculations of Raman spectroscopic biosignatures. J Mol Model 2014; 20:2157. [DOI: 10.1007/s00894-014-2157-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 01/22/2014] [Indexed: 10/25/2022]
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Edwards HGM, Vandenabeele P, Jehlicka J, Benoy TJ. An analytical Raman spectroscopic study of an important english oil painting of the 18th Century. Spectrochim Acta A Mol Biomol Spectrosc 2014; 118:598-602. [PMID: 24095770 DOI: 10.1016/j.saa.2013.07.059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 07/06/2013] [Accepted: 07/21/2013] [Indexed: 06/02/2023]
Abstract
An opportunity was afforded to analyse pigment specimens from an unrestored oil painting in the style of the English School of the mid-18th Century prior to conservation being undertaken. Raman spectroscopy was adopted to characterise the pigments and indicated the presence of a novel red pigment which was assigned to the complex chromium mineral, hemihedrite, in addition to other interesting materials found in combination. This is the first recorded identification of hemihedrite spectral signals in an art context in a range of mineral pigments that are otherwise typical of this period and some hypotheses are presented to explain its presence based on its occurrence with associated mineral pigments. It is suggested that the presence of powdered glass identified in certain areas of the painting enhanced the reflectivity of the pigment matrix.
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Affiliation(s)
- Howell G M Edwards
- Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK.
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35
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Varnali T, Edwards HGM. Reduced and oxidised scytonemin: theoretical protocol for Raman spectroscopic identification of potential key biomolecules for astrobiology. Spectrochim Acta A Mol Biomol Spectrosc 2014; 117:72-77. [PMID: 23981417 DOI: 10.1016/j.saa.2013.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 07/23/2013] [Accepted: 08/02/2013] [Indexed: 06/02/2023]
Abstract
Scytonemin is an important UV-radiation protective biomolecule synthesised by extremophilic cyanobacteria in stressed terrestrial environments. Scytonemin and its reduced form have been both isolated experimentally and the Raman spectrum for scytonemin has been assigned and characterised experimentally both in extracts and in living extremophilic cyanobacterial colonies. Scytonemin is recognised as a key biomarker molecule for terrestrial organisms in stressed environments. We propose a new, theoretically plausible structure for oxidised scytonemin which has not been mentioned in the literature hitherto. DFT calculations for scytonemin, reduced scytonemin and the new structure modelled and proposed for oxidised scytonemin are reported along with their Raman spectroscopic data and λmax UV-absorption data obtained theoretically. Comparison of the vibrational spectroscopic assignments allows the three forms of scytonemin to be detected and identified and assist not only in the clarification of the major features in the experimentally observed Raman spectral data for the parent scytonemin but also support a protocol proposed for their analytical discrimination. The results of this study provide a basis for the search for molecules of this type in future astrobiological missions of exploration and the search for extinct and extant life terrestrially.
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Affiliation(s)
- Tereza Varnali
- Department of Chemistry, Faculty of Arts and Sciences, Bogazici University, Bebek 34342, Istanbul, Turkey.
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36
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Vandenabeele P, Edwards HGM, Jehlička J. The role of mobile instrumentation in novel applications of Raman spectroscopy: archaeometry, geosciences, and forensics. Chem Soc Rev 2014; 43:2628-49. [PMID: 24382454 DOI: 10.1039/c3cs60263j] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The applications of analytical Raman spectroscopy in the characterisation of materials associated with archaeologically excavated artefacts, forensic investigations of drugs of abuse, security and crime scenes, minerals and rocks and future astrobiological space missions are now well established; however, these applications have emphasised the need for new developments in the area of miniaturised instrumentation which extends the concept and breadth of the analytical requirement to facilitate the provision of data from 'in field' studies. In this respect, the apparently unrelated themes of art and archaeology, forensic science, geological science and astrobiology as covered by this review are unified broadly by the ability to record data nondestructively and without resorting to sampling and the subsequent transfer of samples to the analytical laboratory. In studies of works of art there has long been a requirement for on-site analysis, especially for valuable paintings held under strict museum security and for wall paintings which cannot physically be removed from their setting; similarly, the use of portable Raman spectroscopy in archaeological and geological field work as a first-pass screening device which obviates the necessity of multiple and wasteful specimen collection is high on the wish-list of practicing spectroscopists. As a first-pass screening probe for forensic crime scenes, Raman spectroscopy has proved to be of inestimable value for the early detection of dangerous and prohibited materials such as drugs of abuse, explosives and their chemical precursors, and banned contraband biomaterials such as ivories and animal products; in these applications the advantage of the Raman spectroscopic technique for the recognition of spectral signatures from mixtures of inorganic and organic compounds is paramount and not afforded by other less portable instrumental techniques. Finally, in astrobiological work, these requirements also apply but with the additional prerequisite for system operation remotely - often over distances of several hundred million kilometres - as part of instrumental suites on robotic spacecraft and planetary landers; this necessitates robust and reliable instrumentation for the observation of unique and characteristic spectral features from the planetary geological surface and subsurface which are dependent on the assignment of both biological and geological band signatures.
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Affiliation(s)
- P Vandenabeele
- Department of Archaeology, Ghent University, Sint-Pietersnieuwstraat 35, B-9000 Ghent, Belgium.
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37
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Ali EMA, Edwards HGM. Analytical Raman spectroscopy in a forensic art context: the non-destructive discrimination of genuine and fake lapis lazuli. Spectrochim Acta A Mol Biomol Spectrosc 2013; 121:415-419. [PMID: 24287050 DOI: 10.1016/j.saa.2013.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 09/29/2013] [Accepted: 11/04/2013] [Indexed: 06/02/2023]
Abstract
The differentiation between genuine and fake lapis lazuli specimens using Raman spectroscopy is assessed using laboratory and portable instrumentation operating at two longer wavelengths of excitation in the near-infrared, namely 1064 and 785 nm. In spite of the differences between the spectra excited here in the near infrared and those reported in the literature using visible excitation, it is clear that Raman spectroscopy at longer wavelengths can provide a means of differentiating between the fakes studied here and genuine lapis lazuli. The Raman spectra obtained from portable instrumentation can also achieve this result, which will be relevant for the verification of specimens which cannot be removed from collections and for the identification of genuine lapis lazuli inlays in, for example, complex jewellery and furniture. The non-destructive and non-contact character of the technique offers a special role for portable Raman spectroscopy in forensic art analysis.
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Affiliation(s)
- Esam M A Ali
- Division of Chemical and Forensic Sciences, University of Bradford, Bradford BD7 1DP, UK.
| | - Howell G M Edwards
- Division of Chemical and Forensic Sciences, University of Bradford, Bradford BD7 1DP, UK
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38
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de Oliveira LN, de Oliveira VE, D'ávila S, Edwards HGM, de Oliveira LFC. Raman spectroscopy as a tool for polyunsaturated compound characterization in gastropod and limnic terrestrial shell specimens. Spectrochim Acta A Mol Biomol Spectrosc 2013; 114:541-546. [PMID: 23792293 DOI: 10.1016/j.saa.2013.05.095] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 05/20/2013] [Accepted: 05/24/2013] [Indexed: 06/02/2023]
Abstract
The colours of mollusc shells were determined using the Raman spectroscopy and these analyses suggest that the conjugated polyenes (carotenoids) and psittacofulvins are the organic pigments incorporated into their skeletal structures responsible by their colorations. The symmetric stretching vibration of the carbonate ion gives rise to a very strong Raman band at ca. 1089 cm(-1) and a weak band at 705 cm(-1), for all samples; the second band characterizes the aragonite as the inorganic matrix and can be used as a marker. The specimens show bands at 1523-1500 and at 1130-1119 cm(-1), assigned to the ν1 and ν2 modes of the polyenic chain vibrations, respectively. Another band at 1293 cm(-1), assigned to the CH=CH in-plane rocking mode of the olefinic hydrogen is also observed in all samples, which reinforces the psittacofulvin compound as the main pigment present in the analyzed samples.
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Affiliation(s)
- Leandra N de Oliveira
- NEEM-Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, Campus Martelos, Juiz de Fora, MG, Brazil
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Jehlička J, Osterrothová K, Oren A, Edwards HGM. Raman spectrometric discrimination of flexirubin pigments from two genera of Bacteroidetes. FEMS Microbiol Lett 2013; 348:97-102. [PMID: 24033756 DOI: 10.1111/1574-6968.12243] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 08/21/2013] [Accepted: 08/25/2013] [Indexed: 11/30/2022] Open
Abstract
Flexirubins are specific polyene pigments produced by several genera of Bacteroidetes. Colonies and cell extracts of Flavobacterium johnsoniae and Flexibacter elegans have been investigated by Raman spectroscopy to show that this fast and non-destructive technique can be used to differentiate these pigments from carotenoids and to compare the flexirubin content of the two microorganisms. The presence or absence of certain distinguishing features in the CH combination band region at 2500-2750 cm(-1) can assist in the discrimination between the two flexirubins investigated. Raman spectroscopy is thus a suitable tool not only to detect flexirubin pigments in bacterial cells, but also to further characterize the pigments present in members of the Bacteroidetes genera that are rich in flexirubins.
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Affiliation(s)
- Jan Jehlička
- Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University, Prague, Czech Republic
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Varnali T, Edwards HGM. Theoretical study of novel complexed structures for methoxy derivatives of scytonemin: potential biomarkers in iron-rich stressed environments. Astrobiology 2013; 13:861-869. [PMID: 23992252 DOI: 10.1089/ast.2013.0980] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Scytonemin is a cyanobacterial sheath pigment with potent UV (UVA, UVB, and UVC) absorbing properties. Di- and tetramethoxy derivatives of scytonemin have also been found and described in the literature. The importance of these biomolecules is their photoprotective function, which is one of the major survival strategies adopted by extremophiles in environmentally stressed conditions. Also, iron compounds [particularly iron(III) oxides] offer an additional UV-protecting facility to subsurface endolithic biological colonization; hence, banded iron formations (accompanied by zones of depletion of iron) in rock matrices have attracted attention with special interest in the method of transportation of iron compounds through the rock. Di- and tetramethoxyscytonemin and their iron(III) complexes have been modeled and studied computationally by using density functional theory calculations at the level of B3LYP/6-31G** methodology. We propose new structures that could feature in survival strategy and facilitate the movement of iron through the rock especially for iron-rich stressed terrestrial environments exemplified by the Río Tinto system with the added potential of subsurface Mars exploration. This study represents a continuation of our previous work on scytonemin. The calculated Raman spectra of the proposed iron complexes are compared with those of their parent compounds and discussed in relation to structural changes effected in the parent ligand upon complexation. This information leads to new insights to be gained by experimental Raman spectroscopists and the characterization of spectroscopic biosignatures for the database being compiled for the remote Raman analytical interrogation of the martian surface and subsurface being proposed for the ESA ExoMars mission planned for launch in 2018.
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Affiliation(s)
- Tereza Varnali
- 1 Department of Chemistry, Bogazici University , Istanbul, Turkey
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41
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Georgopoulos SL, Edwards HGM, de Oliveira LFC. Raman spectroscopic analysis of the interaction between squaric acid and dimethylsulfoxide. Spectrochim Acta A Mol Biomol Spectrosc 2013; 111:54-61. [PMID: 23603576 DOI: 10.1016/j.saa.2013.03.052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 03/07/2013] [Accepted: 03/12/2013] [Indexed: 06/02/2023]
Abstract
The investigation of solutions of squaric acid in dimethylsulfoxide (DMSO) by Raman spectroscopy has facilitated the observation of the presence of different species derived from squaric acid such as the squarate dianion in solutions of 0.3M and 0.5M concentration and the hydrogen-squarate ion in solution concentrations greater than 2.0M. The method described by Alía and coworkers was used to calculate the two pK values corresponding to the ions produced by squaric acid interacting with DMSO: the hydrogen squarate (pK1=0.80) ion and the squarate dianion (pK2=0.84). From the spectroscopic data it has been also possible to determine the complex formation between associated squaric acid/DMSO in the proportion squaric acid 1:1 DMSO in which the associated squaric acid is hydrogen-bonded to the S atom in the DMSO structure.
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Affiliation(s)
- Stéfanos L Georgopoulos
- Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Universidade Federal de Juiz de Fora, Juiz de Fora, MG 36036-900, Brazil
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Vítek P, Jehlička J, Edwards HGM. Practical considerations for the field application of miniaturized portable Raman instrumentation for the identification of minerals. Appl Spectrosc 2013; 67:767-78. [PMID: 23816130 DOI: 10.1366/12-06774] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The nondestructive identification of both inorganic and organic compounds without the need for chemical or mechanical sample preparation is an advantage of the Raman spectroscopic analytical technique when applied in situ using miniaturized equipment for the geosciences. This is critically assessed here for several real life geoscientific scenarios in which several groups of minerals were analyzed with emphasis on evaporites, carbonates, and selected types of dark minerals and weak Raman scatterers. The role of individual analytical instrumental parameters such as focal plane precision, exposure time, and ambient light conditions that can affect the acquisition and interpretation of spectroscopic data from these specimens in field conditions was also evaluated.
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Affiliation(s)
- Petr Vítek
- Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague, Albertov 6, 128 43 Prague 2, Czech Republic.
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43
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Jehlička J, Edwards HGM, Oren A. Bacterioruberin and salinixanthin carotenoids of extremely halophilic Archaea and Bacteria: a Raman spectroscopic study. Spectrochim Acta A Mol Biomol Spectrosc 2013; 106:99-103. [PMID: 23376264 DOI: 10.1016/j.saa.2012.12.081] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/18/2012] [Accepted: 12/21/2012] [Indexed: 05/08/2023]
Abstract
Laboratory cultures of a number of red extremely halophilic Archaea (Halobacterium salinarum strains NRC-1 and R1, Halorubrum sodomense, Haloarcula valismortis) and of Salinibacter ruber, a red extremely halophilic member of the Bacteria, have been investigated by Raman spectroscopy using 514.5nm excitation to characterize their carotenoids. The 50-carbon carotenoid α-bacterioruberin was detected as the major carotenoid in all archaeal strains. Raman spectroscopy also detected bacterioruberin as the main pigment in a red pellet of cells collected from a saltern crystallizer pond. Salinibacter contains the C40-carotenoid acyl glycoside salinixanthin (all-E, 2'S)-2'-hydroxy-1'-[6-O-(methyltetradecanoyl)-β-d-glycopyranosyloxy]-3',4'-didehydro-1',2'-dihydro-β,ψ-carotene-4-one), for which the Raman bands assignments of are given here for the first time.
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Affiliation(s)
- J Jehlička
- Charles University, Institute of Geochemistry, Mineralogy and Mineral Resources, Prague, Czech Republic.
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Munshi T, Brewster VL, Edwards HGM, Hargreaves MD, Jilani SK, Scowen IJ. Monitoring of the interconversion of gamma-butyrolactone (GBL) to gamma hydroxybutyric acid (GHB) by Raman spectroscopy. Drug Test Anal 2012; 5:678-82. [DOI: 10.1002/dta.1438] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 10/15/2012] [Accepted: 10/16/2012] [Indexed: 11/06/2022]
Affiliation(s)
- Tasnim Munshi
- Chemical & Forensic Sciences; University of Bradford; Bradford; BD7 1DP; UK
| | - Victoria. L. Brewster
- School of Chemistry, Manchester Interdisciplinary Biocentre; University of Manchester; 131 Princess Street; Manchester; M1 7DN; UK
| | | | - Michael D. Hargreaves
- Thermo Scientific Portable Optical Analyzers; Thermo Fisher Scientific; Wilmington; MA; USA
| | - Shelina. K. Jilani
- Chemical & Forensic Sciences; University of Bradford; Bradford; BD7 1DP; UK
| | - Ian J Scowen
- Chemical & Forensic Sciences; University of Bradford; Bradford; BD7 1DP; UK
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Vítek P, Jehlička J, Edwards HGM, Hutchinson I, Ascaso C, Wierzchos J. The miniaturized Raman system and detection of traces of life in halite from the Atacama Desert: some considerations for the search for life signatures on Mars. Astrobiology 2012; 12:1095-9. [PMID: 23151300 PMCID: PMC3522129 DOI: 10.1089/ast.2012.0879] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 07/18/2012] [Indexed: 05/18/2023]
Abstract
Raman spectroscopy is being adopted as a nondestructive instrumentation for the robotic exploration of Mars to search for traces of life in the geological record. Here, miniaturized Raman spectrometers of two different types equipped with 532 and 785 nm lasers for excitation, respectively, were compared for the detection of microbial biomarkers in natural halite from the hyperarid region of the Atacama Desert. Measurements were performed directly on the rock as well as on the homogenized, powdered samples prepared from this material-the effects of this sample preparation and the excitation wavelength employed in the analysis are compared and discussed. From these results, 532 nm excitation was found to be superior for the analysis of powdered specimens due to its high sensitivity toward carotenoids and hence a higher capability for their detection at relatively low concentration in bulk powdered specimens. For the same reason, this wavelength was a better choice for the detection of carotenoids in direct measurements made on the rock samples. The 785 nm excitation wavelength, in contrast, proved to be more sensitive toward the detection of scytonemin.
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Affiliation(s)
- Petr Vítek
- Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague, 128 43 Prague 2, Czech Republic.
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Edwards HGM, Hutchinson I, Ingley R. The ExoMars Raman spectrometer and the identification of biogeological spectroscopic signatures using a flight-like prototype. Anal Bioanal Chem 2012; 404:1723-31. [DOI: 10.1007/s00216-012-6285-z] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 06/25/2012] [Accepted: 07/18/2012] [Indexed: 11/30/2022]
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47
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Bowen RD, Edwards HGM, Varnali T. Influence of a methyl substituent on the Raman spectrum of but-3-enyl methyl ether. Spectrochim Acta A Mol Biomol Spectrosc 2012; 93:26-32. [PMID: 22465764 DOI: 10.1016/j.saa.2012.02.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 02/10/2012] [Indexed: 05/31/2023]
Abstract
The Raman spectrum of but-3-enyl methyl ether, CH(2)CHCH(2)CH(2)OCH(3) is reported and compared with those of its homologues in which a methyl group is substituted for a hydrogen atom on one of the carbon atoms of the alkenyl chain. Attention is focused on the influence of this methyl group on the bands in the spectrum associated with specific CH, skeletal stretching and bending vibrations. The use of ab initio DFT quantum mechanical calculations to assist in making these assignments reveals a high degree of mode-mixing in the skeletal vibrations. The value of model studies of this kind in refining the correlations between the presence and absence of specific bands in a Raman spectrum with molecular structure is emphasised.
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Affiliation(s)
- Richard D Bowen
- Chemical and Forensic Sciences, School of Life Sciences, University of Bradford, Bradford, West Yorkshire BD7 1DP, United Kingdom.
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Dartnell LR, Page K, Jorge-Villar SE, Wright G, Munshi T, Scowen IJ, Ward JM, Edwards HGM. Destruction of Raman biosignatures by ionising radiation and the implications for life detection on Mars. Anal Bioanal Chem 2012; 403:131-44. [DOI: 10.1007/s00216-012-5829-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 02/01/2012] [Accepted: 02/01/2012] [Indexed: 10/28/2022]
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49
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Vítek P, Ali EMA, Edwards HGM, Jehlička J, Cox R, Page K. Evaluation of portable Raman spectrometer with 1064 nm excitation for geological and forensic applications. Spectrochim Acta A Mol Biomol Spectrosc 2012; 86:320-7. [PMID: 22079176 DOI: 10.1016/j.saa.2011.10.043] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 08/26/2011] [Accepted: 10/17/2011] [Indexed: 05/16/2023]
Abstract
The development of miniaturized Raman instrumentation is in demand for applications relevant to forensic, pharmaceutical and art analyses, as well as geosciences, and planetary exploration. In this study we report on evaluation of a portable dispersive Raman spectrometer equipped with 1064 nm laser excitation. Selected samples from geological, geobiological and forensic areas of interest have been studied from which the advantages, disadvantages and the analytical potential of the instrument are assessed based on a comparison with bench instrumentation and other portable Raman spectrometers using 785 nm excitation. It is demonstrated that the instrument operating with 1064 nm excitation has potential for expanding the number and types of samples that can be measured by miniaturized Raman spectroscopy without interfering fluorescence background emission. It includes inorganic and organic minerals, biomolecules within living lichen and endolithic cyanobacteria as well as drugs of abuse and explosives.
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Affiliation(s)
- Petr Vítek
- Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague, Albertov 6, 128 43 Prague 2, Czech Republic.
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50
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Jehlička J, Vandenabeele P, Edwards HGM. Discrimination of zeolites and beryllium containing silicates using portable Raman spectroscometric equipment with near-infrared excitation. Spectrochim Acta A Mol Biomol Spectrosc 2012; 86:341-346. [PMID: 22099060 DOI: 10.1016/j.saa.2011.10.046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 10/19/2011] [Accepted: 10/20/2011] [Indexed: 05/31/2023]
Abstract
In this paper Raman spectra were obtained for a series of zeolites (thomsonite, stilbite, natrolite) and beryllium containing silicates (beryl, chrysoberyl, euclase, phenacite, bavenite, milarite) using a portable Raman specrometer with a 785 nm laser excitation to show the possibility to apply this setting for unambiguous detection and discrimination of these silicate minerals. Obtained spectra contain the most intense Raman bands at the same positions ±2-4 cm(-1) as reported in the literature. The use of these bands permits the unambiguous identification of these phases. Data show the possibility to discriminate individual species of similar whitish color and aspect. Measurements showed an excellent correspondence of Raman bands obtained using the portable system and a laboratory Raman microspectrometer (with the same excitation laser wavelenght). However, for several minerals of these groups (chrysoberyl, bertrandite, chiavennite) Raman spectra were not of sufficient quality to permit unambiguous identification. The reasons are discussed. Raman spectrum of chiavennite CaMnBe(2)Si(5)O(13)(OH)(2)·2(H(2)O) - a transformation product occurring together with bavenite on the surface of beryl crystals was obtained for the first time using the laboratory Raman spectrometer.
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Affiliation(s)
- J Jehlička
- Charles University in Prague, Institute of Geochemistry, Mineralogy and Mineral Resources, Prague, Czech Republic.
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