Change search
Refine search result
1 - 4 of 4
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Lindgren, Johan
    et al.
    Lund University, Sweden.
    Moyer, Alison E.
    North Carolina State University, US.
    Schweitzer, Mary Higby
    Lund University, Sweden; North Carolina State University, US; North Carolina Museum of Natural Sciences, US.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Medicinteknik.
    Uvdal, Peter
    Lund University, Sweden.
    Nilsson, Dan Eric
    Lund University, Sweden.
    Heimdal, Jimmy
    Lund University, Sweden.
    Engdahl, Anders
    Lund University, Sweden.
    Gren, Johan A.
    Lund University, Sweden.
    Schultz, Bo Pagh
    MUSERUM, Denmark.
    Kear, Benjamin P.
    Uppsala University, Sweden.
    Interpreting melanin-based coloration through deep time: A critical Review2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1813, article id 20150614Article, review/survey (Refereed)
    Abstract [en]

    Colour, derived primarily from melanin and/or carotenoid pigments, is integral to many aspects of behaviour in living vertebrates, including social signalling, sexual display and crypsis. Thus, identifying biochromes in extinct animals can shed light on the acquisition and evolution of these biological traits. Both eumelanin and melanin-containing cellular organelles (melanosomes) are preserved in fossils, but recognizing traces of ancient melanin-based coloration is fraught with interpretative ambiguity, especially when observations are based on morphological evidence alone. Assigning microbodies (or, more often reported, their ‘mouldic impressions’) as melanosome traces without adequately excluding a bacterial origin is also problematic because microbes are pervasive and intimately involved in organismal degradation. Additionally, some forms synthesize melanin. In this review, we survey both vertebrate and microbial melanization, and explore the conflicts influencing assessment of microbodies preserved in association with ancient animal soft tissues.We discuss the types of data used to interpret fossil melanosomes and evaluate whether these are sufficient for definitive diagnosis. Finally, we outline an integrated morphological and geochemical approach for detecting endogenous pigment remains and associated microstructures in multimillion-year-old fossils.

  • 2.
    Siljeström, Sandra
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Parenteau, Mary
    Carnegie Institution of Washington, USA.
    Jahnke, Linda
    NASA Ames Research Center, USA.
    Cady, Sherry
    Pacific Northwest National Laboratory, USA.
    A comparative ToF-SIMS and GC–MS analysis of phototrophic communities collected from an alkaline silica-depositing hotspring2017In: Organic Geochemistry, ISSN 0146-6380, E-ISSN 1873-5290, Vol. 109, p. 14-30Article in journal (Refereed)
    Abstract [en]

    One of few techniques that is able to spatially resolve chemical data, including organic molecules, to morphologicalfeatures in modern and ancient geological samples, is time-of-flight secondary ion mass spectrometry(ToF-SIMS). The ability to connect chemical data to morphology is key for interpreting thebiogenicity of preserved remains in ancient samples. However, due to the lack of reference data for geologicallyrelevant samples and the ease with which samples can be contaminated, ToF-SIMS data may bedifficult to interpret. In this project, we aimed to build a ToF-SIMS spectral database by performing parallelToF-SIMS and gas chromatography–mass spectrometry (GC–MS) analyses of extant photosyntheticmicrobial communities collected from an alkaline silica-depositing hot spring in Yellowstone NationalPark, USA. We built the library by analyzing samples of increasing complexity: pure lipid standards commonlyfound in thermophilic phototrophs, solvent extracts of specific lipid fractions, total lipid extracts,pure cultures of dominant phototrophic community members, and unsilicified phototrophic streamercommunities.The results showed that important lipids and pigments originating from phototrophs were detected byToF-SIMS (e.g., wax esters, monogalactosyldiacylglycerol, digalactosyldiacylglycerol, sufloquinovosyldiaglycerol,alkanes, etc.) in the streamer lipid extracts. Many of the lipids were also detected in situin the unsilicified streamer, and could even be spatially resolved to individual cells within the streamercommunity. Together with the ToF-SIMS database, this mapping ability will be used to further exploreother microbial mats and their fossilized counterparts in the geological record. This is likely to expandthe geochemical understanding of these types of samples.

  • 3.
    Thiel, V.
    et al.
    University of Göttingen, Germany.
    Lausmaa, Jukka
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Medicinteknik.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Medicinteknik.
    Ragazzi, E.
    University of Padova, Italy.
    Seyfullah, L. J.
    University of Göttingen, Germany.
    Schmidt, A. R.
    University of Göttingen, Germany.
    Microbe-like inclusions in tree resins and implications for the fossil record of protists in amber2016In: Geobiology, ISSN 1472-4677, E-ISSN 1472-4669, Vol. 14, no 4, p. 364-373Article in journal (Refereed)
    Abstract [en]

    During the past two decades, a plethora of fossil micro-organisms have been described from various Triassic to Miocene ambers. However, in addition to entrapped microbes, ambers commonly contain microscopic inclusions that sometimes resemble amoebae, ciliates, microfungi, and unicellular algae in size and shape, but do not provide further diagnostic features thereof. For a better assessment of the actual fossil record of unicellular eukaryotes in amber, we studied equivalent inclusions in modern resin of the Araucariaceae; this conifer family comprises important amber-producers in Earth history. Using time-of-flight secondary ion mass spectrometry (ToF-SIMS), we investigated the chemical nature of the inclusion matter and the resin matrix. Whereas the matrix, as expected, showed a more hydrocarbon/aromatic-dominated composition, the inclusions contain abundant salt ions and polar organics. However, the absence of signals characteristic for cellular biomass, namely distinctive proteinaceous amino acids and lipid moieties, indicates that the inclusions do not contain microbial cellular matter but salts and hydrophilic organic substances that probably derived from the plant itself. Rather than representing protists or their remains, these microbe-like inclusions, for which we propose the term 'pseudoinclusions', consist of compounds that are immiscible with the terpenoid resin matrix and were probably secreted in small amounts together with the actual resin by the plant tissue. Consequently, reports of protists from amber that are only based on the similarity of the overall shape and size to extant taxa, but do not provide relevant features at light-microscopical and ultrastructural level, cannot be accepted as unambiguous fossil evidence for these particular groups.

  • 4. Thiel, V.
    et al.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Medicinteknik.
    Time-of-flight secondary ion mass spectrometry (TOF-SIMS): Principles and practice in the biogeosciences2014In: Principles and practice of analytical techniques in Geosciences / [ed] Kliti Grice, Royal Society of Chemistry, 2014, no 4, p. 122-170Chapter in book (Refereed)
    Abstract [en]

    Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provides chemical information on the outermost molecular layers of sample surfaces without solvent extraction. In TOF-SIMS, a pulsed beam of high-energy ions (primary ions) is scanned over a selected analysis area on the sample. During the primary ion bombardment, neutral and charged particles (secondary ions) are released from the outermost molecular layers of the sample surface. Analysis of the secondary ions in a TOF analyser yields a mass spectral data set that allows the retrospective production of(1) ion images showing the spatial signal intensity distribution from selected ions over the analysis area; (2) mass spectra from the total analysis area; or (3) mass spectra from user-defined regions of interest inside the analysis area. In the so-called static SIMS regime, the primary ions are provided in very short pulses and the analysis is completed before the incoming primary ions damage a significant fraction of the surface. Static TOF-SIMS is therefore capable of providing molecularly specific secondary ions, and thus mass spectra with detailed organic information, which is not possible with other (‘dynamic’) SIMS techniques. In this chapter, we describe the principles of static TOF-SIMS instrumentation and data evaluation, review a number of relevant applications, and discuss the potential of this technique in the biogeosciences, with a focus on organic biomarker applications.

1 - 4 of 4
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
v. 2.35.9