Calcification of Keratin

Blakey, P. R.; Earland, Christopher; Stell, J. G. P.

doi:10.1038/198481a0

Cited by 29 publications

(15 citation statements)

References 2 publications

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“…Chemical elements such as Cl, together with Al and Mg may contribute to exoskeleton biomineralization of protein components and coating [6] , [7] . The structural proteins described in arthropod exoskeleton and cytoskeleton include keratins and desmoplakin [8] , [9] , which are involved in biomineralization processes [10] , [11] . The structural proteins in blood-feeding arthropods such as ticks may derive from both host and ectoparasite and the levels of tick and host derived proteins vary in response to pathogen infection [12] , [13] , [14] , [15] .…”

Section: Resultsmentioning

confidence: 99%

Anaplasma pathogen infection alters chemical composition of the exoskeleton of hard ticks (Acari: Ixodidae)

Fuente

Lima-Barbero

Prado

et al. 2020

Computational and Structural Biotechnology Journal

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Ticks are arthropod ectoparasites and vectors of pathogens affecting human and animal health worldwide. The exoskeleton is a structure that protect arthropods from natural threats such as predators and diseases. Both structural proteins and chemical elements are components of the exoskeleton. However, the chemical composition and effect of pathogen infection on tick exoskeleton properties has not been characterized. In this study, we characterized the chemical composition of tick exoskeleton and the effect of Anaplasma pathogen infection on the chemical elements of the exoskeleton and selected structural proteins. The chemical composition was characterized ventral, dorsal upper and dorsal lower regions of tick exoskeleton by scanning electron microscopy and energy dispersive spectroscopy and compared between infected and uninfected ticks. The levels of selected structural proteins were analyzed in infected and uninfected I. scapularis salivary glands by immunofluorescence analysis. The results showed that tick exoskeleton contains chemical elements also found in other arthropods. Some of the identified elements such as Mg and Al may be involved in tick exoskeleton stabilization through biomineralization of structural proteins that may be overrepresented in response to pathogen infection. These results suggested that pathogen infection alters the chemical composition of tick exoskeleton by mechanisms still to be characterized and with tick species and exoskeleton region-specific differences.

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Section: Resultsmentioning

confidence: 99%

Anaplasma pathogen infection alters chemical composition of the exoskeleton of hard ticks (Acari: Ixodidae)

Fuente

Lima-Barbero

Prado

et al. 2020

Computational and Structural Biotechnology Journal

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“…Non‐pigmented feathers and scales leave no organic residue, but can still preserve through residues of calcium phosphate, known to harden keratinous tissues in vivo (Blakey et al . ; Pautard , ), which can be detected through fluorescence imaging (Mayr et al . ; Vinther et al .…”

Section: The Role and Challenges Of Maturation Experimentsmentioning

confidence: 99%

Sediment‐encased maturation: a novel method for simulating diagenesis in organic fossil preservation

Saitta

Kaye²,

Vinther

2018

Palaeontology

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Exceptional fossils can preserve diageneticallyaltered biomolecules. Understanding the pathways that lead to such preservation is vital to utilizing fossil information in evolutionary and palaeoecological studies. Experimental taphonomy explores the stability of tissues during microbial/ autolytic decay or their molecular stability through maturation under high pressure and temperature. Maturation experiments often take place inside sealed containers, preventing the loss of labile, mobile or volatile molecules. However, wrapping tissues inside aluminium foil, for example, can create too open a system, leading to loss of both labile and recalcitrant materials. We present a novel experimental procedure for maturing tissues under elevated pressure/temperature inside compacted sediment. In this procedure, porous sediment allows maturation breakdown products to escape into the sediment and maturation chamber, while recalcitrant, immobile components are contained, more closely mimicking the natural conditions of fossilization. To test the efficacy of this procedure in simulating fossil diagenesis, we investigate the differential survival of melanosomes relative to proteinaceous tissues through maturation of fresh lizard body parts and feathers. Macro-and ultrastructures are then compared to fossils. Similar to many carbonaceous exceptional fossils, the resulting organic components are thin, dark films composed mainly of exposed melanosomes resting on the sediment in association with darkened bones. Keratinous, muscle, collagenous and adipose tissues appear to be lost. Such results are consistent with predictions derived from non-sediment-encased maturation experiments and our understanding of biomolecular stability. These experiments also suggest that organic preservation is largely driven by the original molecular composition of the tissue and the diagenetic stability of those molecules, rather than the tissue's decay resistance alone; this should be experimentally explored in the future.

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“…Some keratinous structures are hardened through deposition of calcium phosphate salts (Pautard ) such as baleen, claws and feather rachises (Blakey et al . ). These salts are known from the fossil record (Mayr et al .…”

mentioning

confidence: 97%

Low fossilization potential of keratin protein revealed by experimental taphonomy

et al. 2017

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Recent studies have suggested the presence of keratin in fossils dating back to the Mesozoic. However, ultrastructural studies revealing exposed melanosomes in many fossil keratinous tissues suggest that keratin should rarely, if ever, be preserved. In this study, keratin's stability through diagenesis was tested using microbial decay and maturation experiments on various keratinous structures. The residues were analysed using pyrolysis‐gas chromatography‐mass spectrometry and compared to unpublished feather and hair fossils and published fresh and fossil melanin from squid ink. Results show that highly matured feathers (200–250°C/250 bars/24 h) become a volatile‐rich, thick fluid with semi‐distinct pyrolysis compounds from those observed in less degraded keratins (i.e. fresh, decayed, moderately matured, and decayed and moderately matured) suggesting hydrolysis of peptide bonds and potential degradation of free amino acids. Neither melanization nor keratin (secondary) structure (e.g. ⍺‐ vs β‐keratin) produced different pyrograms; melanin pyrolysates are largely a subset of those from proteins, and proteins have characteristic pyrolysates. Analyses of fossil fur and feather found a lack of amides, succinimide and piperazines (present even in highly matured keratin) and showed pyrolysis compounds more similar to fossil and fresh melanin than to non‐matured or matured keratin. Although the highly matured fluid was not water soluble at room temperature, it readily dissolved at elevated temperatures easily attained during diagenesis, meaning it could leach away from the fossil. Future interpretations of fossils must consider that calcium phosphate and pigments are the only components of keratinous structures known to survive fossilization in mature sediments.

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Calcification of Keratin

Cited by 29 publications

References 2 publications

Anaplasma pathogen infection alters chemical composition of the exoskeleton of hard ticks (Acari: Ixodidae)

Anaplasma pathogen infection alters chemical composition of the exoskeleton of hard ticks (Acari: Ixodidae)

Sediment‐encased maturation: a novel method for simulating diagenesis in organic fossil preservation

Low fossilization potential of keratin protein revealed by experimental taphonomy

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