Biomarkers and their Raman spectroscopic signatures: a spectral challenge for analytical astrobiology

Edwards, Howell G. M.; Hutchinson, Ian; Ingley, Richard; Jehlička, Jan

doi:10.1098/rsta.2014.0193

Cited by 59 publications

(32 citation statements)

References 48 publications

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“…Such pigments are synthesized by a vast range of living organisms, including extremophiles that produce them as part of suites of protectant molecules to aid in the survival of such organisms in hostile environments (Sinha and Häder, 2008). These molecules have been used for some time as biomarkers in terrestrial environments , and it has been suggested that they may also be suitable targets for planetary astrobiology missions (Parnell et al, 2007;McKay et al, 2008;Edwards, 2010;Edwards et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Selection of Portable Spectrometers for Planetary Exploration: A Comparison of 532 nm and 785 nm Raman Spectroscopy of Reduced Carbon in Archean Cherts

et al. 2015

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Knowledge and understanding of the martian environment has advanced greatly over the past two decades, beginning with NASA's return to the surface of Mars with the Pathfinder mission and its rover Sojourner in 1997 and continuing today with data being returned by the Curiosity rover. Reduced carbon, however, is yet to be detected on the martian surface, despite its abundance in meteorites originating from the planet. If carbon is detected on Mars, it could be a remnant of extinct life, although an abiotic source is much more likely. If the latter is the case, environmental carbonaceous material would still provide a source of carbon that could be utilized by microbial life for biochemical synthesis and could therefore act as a marker for potential habitats, indicating regions that should be investigated further. For this reason, the detection and characterization of reduced or organic carbon is a top priority for both the ESA/Roscosmos ExoMars rover, currently due for launch in 2018, and for NASA's Mars 2020 mission. Here, we present a Raman spectroscopic study of Archean chert Mars analog samples from the Pilbara Craton, Western Australia. Raman spectra were acquired with a flight-representative 532 nm instrument and a 785 nm instrument with similar operating parameters. Reduced carbon was successfully detected with both instruments; however, its Raman bands were detected more readily with 785 nm excitation, and the corresponding spectra exhibited superior signal-to-noise ratios and reduced background levels.

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Section: Discussionmentioning

confidence: 99%

Selection of Portable Spectrometers for Planetary Exploration: A Comparison of 532 nm and 785 nm Raman Spectroscopy of Reduced Carbon in Archean Cherts

et al. 2015

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“…For detecting them in the frame of future Mars missions, the application of Raman spectroscopy was proposed [38][39][40]. In fact, it was shown that on the Earth carotenoids can unambiguously be detected in lichen encrustations [41][42][43][44].…”

Section: Discussionmentioning

confidence: 99%

Potential and limits of Raman spectroscopy for carotenoid detection in microorganisms: implications for astrobiology

Jehlička

Edwards

Osterrothová

et al. 2014

Phil. Trans. R. Soc. A.

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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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“…Brownish to black scytonemin is a well‐known UV protective pigment from some cyanobacteria Scytonema , Calothrix , Lynbya. Its distribution was investigated in endolithic microbial communities within the rocks from the Atacama desert, and it is considered as a good biomarker for future exobiological explorations . Other usually dark pigments, such as melanins, play similar protective roles in bacteria, fungi and animals including human.…”

Section: Introductionmentioning

confidence: 99%

Raman microspectrometric study of pigments in melanized fungi from the hyperarid Atacama desert gypsum crust

Culka

Jehlička

Ascaso

et al. 2017

J Raman Spectroscopy

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The Atacama desert is amongst the oldest and driest deserts in the world, and its hyperarid core is described as ‘the most barren region imaginable’. In this study, we describe for the first time the endolithic microbial communities composed by eukaryotic microorganisms, such as melanized fungi and algae, colonizing the interior of gypsum crusts collected in the hyperarid zone of the Atacama desert. Melanin pigments present in fungi cell walls have been studied by Raman microspectroscopy. Analyses have been performed directly in the gypsum crust sustaining the colonisation of fungi and algae, on the thin sections and on the cultivated culture of the fungi from Neocatenulostroma genus. Raman spectroscopic signature of melanin has been clearly observed in all the sample types. Two broad bands located at wavenumbers 1605–1580 cm−1 and around 1350 cm−1 have been detected in all the studied samples, with slight variations in the appearance of other bands or shoulders of smaller intensity documenting either the changes in melanin composition or other biomolecules bound to melanin. Blue and green lasers (445, 514 and 532 nm) have been shown as favourable excitation for the study of melanins as the longer wavelengths induced adverse effects that mask the Raman signal. Effect of laser power level on the resulting spectra has also been discussed. Algal carotenoid pigment has been detected in isolated regions of the sample by the Raman bands of 1520, 1155 and 1002 cm−1. The strong Raman signal of fungal melanin that has been detected in the host rock from the locality characterized by extreme conditions such as Atacama desert could be considered in the discussion about feasible biomarker molecules; however, low specificity of the broad Raman signature and similarity to the spectrum of amorphous carbon must be also taken into account. Copyright © 2017 John Wiley & Sons, Ltd.

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Biomarkers and their Raman spectroscopic signatures: a spectral challenge for analytical astrobiology

Cited by 59 publications

References 48 publications

Selection of Portable Spectrometers for Planetary Exploration: A Comparison of 532 nm and 785 nm Raman Spectroscopy of Reduced Carbon in Archean Cherts

Selection of Portable Spectrometers for Planetary Exploration: A Comparison of 532 nm and 785 nm Raman Spectroscopy of Reduced Carbon in Archean Cherts

Potential and limits of Raman spectroscopy for carotenoid detection in microorganisms: implications for astrobiology

Raman microspectrometric study of pigments in melanized fungi from the hyperarid Atacama desert gypsum crust

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