Journal Articles

  • Structural investigation of the interaction between the tandem SH3 domains of c-Cbl-associated protein and vinculin
    [Jun 2014]

    Publication date: Available online 28 May 2014
    Source:Journal of Structural Biology

    Author(s): Debiao Zhao , Xuejuan Wang , Junhui Peng , Chongyuan Wang , Fudong Li , Qianqian Sun , Yibo Zhang , Jiahai Zhang , Gang Cai , Xiaobing Zuo , Jihui Wu , Yunyu Shi , Zhiyong Zhang , Qingguo Gong

    c-Cbl-associated protein (CAP) is an important cytoskeletal adaptor protein involved in the regulation of adhesion turnover. The interaction between CAP and vinculin is critical for the recruitment of CAP to focal adhesions. The tandem SH3 domains (herein termed SH3a and SH3b) of CAP are responsible for its interaction with vinculin. However, the structural mechanism underlying the interaction between CAP and vinculin is poorly understood. In this manuscript, we report the solution structure of the tandem SH3 domains of CAP. Our NMR and ITC data indicate that the SH3a and SH3b domains of CAP simultaneously bind to a long proline-rich region of vinculin with different binding specificities. Furthermore, the crystal structures of the individual SH3a and SH3b domains complexed with their substrate peptides indicate that Q807SH3a and D881SH3b are the critical residues determining the different binding specificities of the SH3 domains. Based on the obtained structural information, a model of the SH3ab-vinculin complex was generated using MD simulation and SAXS data.





    Categories: Journal Articles
  • Corrigendum to “A simple Fourier filter for suppression of the missing wedge ray artefacts in single-axis electron tomographic reconstructions” [J. Struct. Biol. 186(1) (2014) 141–152]
    [Jun 2014]

    Publication date: Available online 27 May 2014
    Source:Journal of Structural Biology

    Author(s): Lubomír Kováčik , Sami Kereïche , Johanna L. Höög , Pavel Jůda , Pavel Matula , Ivan Raška







    Categories: Journal Articles
  • Heparin induced dimerization of APP is primarily mediated by E1 and regulated by its acidic domain
    [Jun 2014]

    Publication date: Available online 22 May 2014
    Source:Journal of Structural Biology

    Author(s): Sandra Hoefgen , Ina Coburger , Dirk Roeser , Yvonne Schaub , Sven O. Dahms , Manuel E. Than

    The amyloid precursor protein (APP) and its cellular processing are believed to be centrally involved in the etiology of Alzheimer’s disease (AD). In addition, many physiological functions have been described for APP, including a role in cell–cell- and cell–ECM-adhesion as well as in axonal outgrowth. We show here the molecular determinants of the oligomerization/dimerization of APP, which is central for its cellular (mis)function. Using size exclusion chromatography (SEC), dynamic light scattering and SEC-coupled static light scattering we demonstrate that the dimerization of APP is energetically induced by a heparin mediated dimerization of the E1 domain, which results in a dimeric interaction of E2. We also show that the acidic domain (AcD) interferes with the dimerization of E1 and propose a model where both, cis- and trans-dimerization occur dependent on cellular localization and function.





    Categories: Journal Articles
  • M-free: Scoring the reference bias in sub-tomogram averaging and template matching
    [Jun 2014]

    Publication date: Available online 22 May 2014
    Source:Journal of Structural Biology

    Author(s): Zhou Yu , Achilleas S. Frangakis

    Cryo-electron tomography provides a snapshot of the cellular proteome. With template matching, the spatial positions of various macromolecular complexes within their native cellular context can be detected. However, the growing awareness of the reference bias introduced by the cross-correlation based approaches, and more importantly the lack of a reliable confidence measurement in the selection of these macromolecular complexes, has restricted the use of these applications. Here we propose a heuristic, in which the reference bias is measured in real space in an analogous way to the R-free value in X-ray crystallography. We measure the reference bias within the mask used to outline the area of the template, and do not modify the template itself. The heuristic works by splitting the mask into a working and a testing area in a volume ratio of 9:1. While the working area is used during the calculation of the cross-correlation function, the information from both areas is explored to calculate the M-free score. We show using artificial data, that the M-free score gives a reliable measure for the reference bias. The heuristic can be applied in template matching and in sub-tomogram averaging. We further test the applicability of the heuristic in tomograms of purified macromolecules, and tomograms of whole Mycoplasma cells.





    Categories: Journal Articles
  • Spherical deconvolution improves quality of single particle reconstruction
    [Jun 2014]

    Publication date: Available online 16 May 2014
    Source:Journal of Structural Biology

    Author(s): Gregory P. Kishchenko , Ardean Leith

    One single-particle reconstruction technique is the reconstruction of macromolecules from projection images of randomly oriented particles (SPRR). In SPRR the reliability and consequent interpretation of the final reconstruction is affected by errors arising from incorrect assignment of projection angles to individual particles. In order to improve the resolution of SPRR we studied the influence of imperfect assignment on 3D blurring. We find that this blurring can be described as a Point Spread Function (PSF) that depends on the distance from geometrical center of the reconstructed volume and that blurring is higher at the periphery. This particular PSF can be described by an almost pure tangential angular function with a negligible radial component. We have developed a reliable algorithm for spherical deconvolution of the 3D reconstruction. This spherical deconvolution operation was tested on reconstructions of GroEL and mitochondrial ribosomes. We show that spherical deconvolution improves the quality of SPRR by reducing blurring and enhancing high frequency components, particularly near the periphery of the reconstruction.





    Categories: Journal Articles
  • Crystal structure of the transport unit of the autotransporter adhesin involved in diffuse adherence from Escherichia coli
    [Jun 2014]

    Publication date: Available online 16 May 2014
    Source:Journal of Structural Biology

    Author(s): Iris Gawarzewski , Frank DiMaio , Elisa Winterer , Britta Tschapek , Sander H.J. Smits , Joachim Jose , Lutz Schmitt

    Several serious gastrointestinal diseases, which are widespread all over the world, are caused by enteropathogenic Escherichia coli. The monomeric autotransporter AIDA-I (adhesin involved in diffuse adherence) represents an important virulence factor of these strains and is involved in adhesion, biofilm formation, aggregation and invasion into host cells. Here, we present the crystal structure of the transport unit of AIDA-I at 3.0Å resolution, which forms a 12-stranded β-barrel harboring the linker domain in its pore. Mutagenesis studies of the C-terminal amino acid demonstrated the great impact of this terminal residue on membrane integration of AIDA-I and passenger translocation.





    Categories: Journal Articles
  • In silico analysis and experimental verification of OSR1 kinase – Peptide interaction
    [Jun 2014]

    Publication date: Available online 9 May 2014
    Source:Journal of Structural Biology

    Author(s): Thomas M. Austin , David P. Nannemann , Samuel L. Deluca , Jens Meiler , Eric Delpire

    The oxidative-stress-responsive kinase 1 (OSR1) and the STE20/SPS1-related proline/alanine-rich kinase (SPAK) are key enzymes in a signaling cascade regulating the activity of Na+–K+–2Cl− cotransporters (NKCC1–2) and Na+–Cl− cotransporter (NCC). Both kinases have a conserved carboxyl-terminal (CCT) domain, which recognizes a unique peptide motif present in OSR1- and SPAK-activating kinases (with-no-lysine kinase 1 (WNK1) and WNK4) as well as their substrates (NKCC1, NKCC2, and NCC). Utilizing various modalities of the Rosetta Molecular Modeling Software Suite including flexible peptide docking and protein design, we comprehensively explored the sequence space recognized by the CCT domain. Specifically, we studied single residue mutations as well as complete unbiased designs of a hexapeptide substrate. The computational study started from a crystal structure of the CCT domain of OSR1 in complex with a hexapeptide derived from WNK4. Point mutations predicted to be favorable include Arg to His or Trp substitutions at position 2 and a Phe to Tyr substitution at position 3 of the hexapeptide. In addition, de novo design yielded two peptides predicted to bind to the CCT domain: FRFQVT and TRFDVT. These results, which indicate a little bit more freedom in the composition of the peptide, were confirmed through the use of yeast two-hybrid screening.





    Categories: Journal Articles
  • Oxygen–aromatic contacts in intra-strand base pairs: Analysis of high-resolution DNA crystal structures and quantum chemical calculations
    [Jun 2014]

    Publication date: Available online 9 May 2014
    Source:Journal of Structural Biology

    Author(s): Alok Jain , R.N.V. Krishna Deepak , Ramasubbu Sankararamakrishnan

    Three-dimensional structures of biomolecules are stabilized by a large number of non-covalent interactions and some of them such as van der Waals, electrostatic and hydrogen bond interactions are well characterized. Delocalized π–electron clouds of aromatic residues are known to be involved in cation–π, CH–π, OH–π and π–π interactions. In proteins, many examples have been found in which the backbone carbonyl oxygen of one residue makes close contact with the aromatic center of aromatic residues. Quantum chemical calculations suggest that such contacts may provide stability to the protein secondary structures. In this study, we have systematically analyzed the experimentally determined high-resolution DNA crystal structures and identified 91 examples in which the aromatic center of one base is in close contact (<3.5Ǻ) with the oxygen atom of preceding (Group-I) or succeeding base (Group-II). Examples from Group-I are overwhelmingly observed and cytosine or thymine is the preferred base contributing oxygen atom in Group-I base pairs. A similar analysis of high-resolution RNA structures surprisingly did not yield many examples of oxygen–aromatic contact of similar type between bases. Ab initio quantum chemical calculations on compounds based on DNA crystal structures and model compounds show that interactions between the bases in base pairs with oxygen–aromatic contacts are energetically favorable. Decomposition of interaction energies indicates that dispersion forces are the major cause for energetically stable interaction in these base pairs. We speculate that oxygen–aromatic contacts in intra-strand base pairs in a DNA structure may have biological significance.





    Categories: Journal Articles
  • Cover 2 - Editorial Board
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2









    Categories: Journal Articles
  • Table of Contents / barcode
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2









    Categories: Journal Articles
  • Correlative Light- and Electron Microscopy with chemical tags
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2

    Author(s): Mario Perkovic , Michael Kunz , Ulrike Endesfelder , Stefanie Bunse , Christoph Wigge , Zhou Yu , Victor-Valentin Hodirnau , Margot P. Scheffer , Anja Seybert , Sebastian Malkusch , Erin M. Schuman , Mike Heilemann , Achilleas S. Frangakis

    Correlative microscopy incorporates the specificity of fluorescent protein labeling into high-resolution electron micrographs. Several approaches exist for correlative microscopy, most of which have used the green fluorescent protein (GFP) as the label for light microscopy. Here we use chemical tagging and synthetic fluorophores instead, in order to achieve protein-specific labeling, and to perform multicolor imaging. We show that synthetic fluorophores preserve their post-embedding fluorescence in the presence of uranyl acetate. Post-embedding fluorescence is of such quality that the specimen can be prepared with identical protocols for scanning electron microscopy (SEM) and transmission electron microscopy (TEM); this is particularly valuable when singular or otherwise difficult samples are examined. We show that synthetic fluorophores give bright, well-resolved signals in super-resolution light microscopy, enabling us to superimpose light microscopic images with a precision of up to 25nm in the x–y plane on electron micrographs. To exemplify the preservation quality of our new method we visualize the molecular arrangement of cadherins in adherens junctions of mouse epithelial cells.





    Categories: Journal Articles
  • Identification of the chemical form of sulfur compounds in the Japanese pink coral (Corallium elatius) skeleton using μ-XRF/XAS speciation mapping
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2

    Author(s): Yusuke Tamenori , Toshihiro Yoshimura , Nguyen Trong Luan , Hiroshi Hasegawa , Atsushi Suzuki , Hodaka Kawahata , Nozomu Iwasaki

    The distributions and chemical forms of sulfur compounds in the skeleton of Japanese pink coral (Corallium elatius) were investigated using X-ray spectroscopic techniques combined with micro-focused soft X-ray radiation. Microscopic X-ray fluorescence/soft X-ray photoabsorption (μ-XRF/XAS) speciation mapping clarified that sulfate is the primary species in the coral skeleton, with minor amounts of organic sulfur, whereas both sulfate and organic sulfur coexist in coenenchyme. Analysis of the post-edge region of the XAS spectra confirmed that sulfate ions in the coral skeleton are mainly in the form of gypsum-like inorganic sulfate substituting for the carbonate ions in the calcite skeleton. The sulfate concentration was negatively correlated with the magnesium concentration and positively correlated with that of phosphorus. Speciation mapping of sulfate in the coral skeleton showed clear fluctuations with sulfate concentrations being higher at dark bands, whereas the small amount of organic sulfur had unclear dark/bright bands. These results suggest that the little organic sulfur that is present is contained in the organic matter embedded in the biocrystal of coral skeleton.





    Categories: Journal Articles
  • Structural insights into regulatory mechanisms of MO25-mediated kinase activation
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2

    Author(s): Qian Hao , Miao Feng , Zhubing Shi , Chuanchuan Li , Min Chen , Wenjia Wang , Meng Zhang , Shi Jiao , Zhaocai Zhou

    The tumor suppressor kinase LKB1 and germinal center kinases (GCKs) are key regulators of various cellular functions. The adaptor molecule MO25 not only recruits and activates LKB1 through the pseudokinase STRAD, but also may directly activate GCKs like MST3, MST4, STK25, OSR1 and SPAK. Targeting MO25 in a pathological setting has been recently studied in mouse. Yet the regulatory mechanism of MO25-mediated kinase activation is not fully understood. Here, our structural studies of MO25-related kinases reveal that MO25 binds to and activates GCK kinases or pseudokinase through a unified structural mechanism, featuring an active conformation of the αC helix and A-loop stabilized by MO25. Compared to GCKs that are directly activated by MO25-binding, activation of LKB1 has evolved additional layer of regulatory machinery, i.e., MO25 “activates” the pseudokinase STRAD, which in turn activates LKB1. Importantly, the structures of MO25α–STK25 and MO25α–MST3 determined in this work represent a transition/intermediate state and a fully activated state, respectively during the MO25-mediated kinase activating process.





    Categories: Journal Articles
  • Frealix: Model-based refinement of helical filament structures from electron micrographs
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2

    Author(s): Alexis Rohou , Nikolaus Grigorieff

    The structures of many helical protein filaments can be derived from electron micrographs of their suspensions in thin films of vitrified aqueous solutions. The most successful and generally-applicable approach treats short segments of these filaments as independent “single particles”, yielding near-atomic resolution for rigid and well-ordered filaments. The single-particle approach can also accommodate filament deformations, yielding sub-nanometer resolution for more flexible filaments. However, in the case of thin and flexible filaments, such as some amyloid-β (Aβ) fibrils, the single-particle approach may fail because helical segments can be curved or otherwise distorted and their alignment can be inaccurate due to low contrast in the micrographs. We developed new software called Frealix that allows the use of arbitrarily short filament segments during alignment to approximate even high curvatures. All segments in a filament are aligned simultaneously with constraints that ensure that they connect to each other in space to form a continuous helical structure. In this paper, we describe the algorithm and benchmark it against datasets of Aβ(1–40) fibrils and tobacco mosaic virus (TMV), both analyzed in earlier work. In the case of TMV, our algorithm achieves similar results to single-particle analysis. In the case of Aβ(1–40) fibrils, we match the previously-obtained resolution but we are also able to obtain reliable alignments and ∼8-Å reconstructions from curved filaments. Our algorithm also offers a detailed characterization of filament deformations in three dimensions and enables a critical evaluation of the worm-like chain model for biological filaments.





    Categories: Journal Articles
  • Two and three dimensional characterization of Zucchini Yellow Mosaic Virus induced structural alterations in Cucurbita pepo L. plants
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2

    Author(s): Günther Zellnig , Michael Herbert Pöckl , Stefan Möstl , Bernd Zechmann

    Infection of plants by Zucchini Yellow Mosaic Virus (ZYMV) induces severe ultrastructural changes. The aim of this study was to investigate ultrastructural changes during ZYMV-infection in Cucurbita pepo L. plants on the two and three dimensional (2D and 3D) level and to correlate these changes with the spread of ZYMV throughout the plant by transmission electron microscopy (TEM) and image analysis. This study revealed that after inoculation of the cotyledons ZYMV moved into roots [3days post inoculation (dpi)], then moved upwards into the stem and apical meristem (5dpi), then into the first true leaf (7dpi) and could finally be found in all plant parts (9dpi). ZYMV-infected cells contained viral inclusion bodies in the form of cylindrical inclusions (CIs). These CIs occurred in four different forms throughout the cytosol of roots and leaves: scrolls and pinwheels when cut transversely and long tubular structures and bundles of filaments when cut longitudinally. 3D reconstruction of ZYMV-infected cells containing scrolls revealed that they form long tubes throughout the cytosol. The majority has a preferred orientation and an average length and width of 3μm and 120nm, respectively. Image analysis revealed an increased size of cells and vacuoles (107% and 447%, respectively) in younger ZYMV-infected leaves leading to a similar ratio of cytoplasm to vacuole (about 1:1) in older and younger ZYMV-infected leaves which indicates advanced cell growth in younger tissues. The collected data advances the current knowledge about ZYMV-induced ultrastructural changes in Cucurbita pepo.





    Categories: Journal Articles
  • Three-dimensional structure of minipig fibrolamellar bone: Adaptation to axial loading
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2

    Author(s): Rotem Almany Magal , Natalie Reznikov , Ron Shahar , Steve Weiner

    Fibrolamellar bone is transiently produced by large, fast growing mammals. The fibrolamellar bone unit is initially formed by elaboration of a network of blood vessels. This is followed by the deposition of a thin, porous and hypercalcified layer, then by the infilling of the vascular cavities by the sequential deposition of a relatively thick rapidly forming bone on both sides of the hypercalcified layer, and finally by lamellar bone. We investigated the 3D structure of the collagenous network of fibrolamellar bone from the femora of a young minipig using mainly the FIB–SEM dual beam microscope and the Serial Surface View method. This enabled us to identify the fibril orientation, the canalicular network organization and other structural motifs within each element of the fibrolamellar unit. The first formed primary hypercalcified layer (PHL) is composed of fibril arrays and multiple small pores, and appears to have an isotropic structure. The major bone component is deposited on both sides of the PHL, and is composed of collagen fibrils with a preferred orientation, mainly aligned parallel to the bone long axis. This bone component is therefore parallel-fibered bone and not woven bone. We also observed that the collagen fibers are organized into bundles. The lamellar bone has most of its collagen fibrils aligned with the bone long axis. This study therefore shows that the large majority of collagen fibrils in fibrolamellar bone are aligned with the bone long axis. This anisotropic structure therefore appears to be adapted to loading along the bone long axis.





    Categories: Journal Articles
  • A method for 3D-reconstruction of a muscle thick filament using the tilt series images of a single filament electron tomogram
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2

    Author(s): G. Márquez , A. Pinto , L. Alamo , B. Baumann , F. Ye , H. Winkler , K. Taylor , R. Padrón

    Myosin interacting-heads (MIH) motifs are visualized in 3D-reconstructions of thick filaments from striated muscle. These reconstructions are calculated by averaging methods using images from electron micrographs of grids prepared using numerous filament preparations. Here we propose an alternative method to calculate the 3D-reconstruction of a single thick filament using only a tilt series images recorded by electron tomography. Relaxed thick filaments, prepared from tarantula leg muscle homogenates, were negatively stained. Single-axis tilt series of single isolated thick filaments were obtained with the electron microscope at a low electron dose, and recorded on a CCD camera by electron tomography. An IHRSR 3D-recontruction was calculated from the tilt series images of a single thick filament. The reconstruction was enhanced by including in the search stage dual tilt image segments while only single tilt along the filament axis is usually used, as well as applying a band pass filter just before the back projection. The reconstruction from a single filament has a 40Å resolution and clearly shows the presence of MIH motifs. In contrast, the electron tomogram 3D-reconstruction of the same thick filament – calculated without any image averaging and/or imposition of helical symmetry – only reveals MIH motifs infrequently. This is – to our knowledge – the first application of the IHRSR method to calculate a 3D reconstruction from tilt series images. This single filament IHRSR reconstruction method (SF-IHRSR) should provide a new tool to assess structural differences between well-ordered thick (or thin) filaments in a grid by recording separately their electron tomograms.





    Categories: Journal Articles
  • Vitrification of Tokuyasu-style immuno-labelled sections for correlative cryo light microscopy and cryo electron tomography
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2

    Author(s): Erik Bos , Leonie Hussaarts , Jan R.T. van Weering , Mark H. Ellisman , Heidi de Wit , Abraham J. Koster

    We present an approach for the preparation of immuno-labelled ultrathin sections from cells or tissue that are compatible with both fluorescence and transmission electron microscopy. Our approach is inspired by a method of Sabanay et al. (1991) that is based on the Tokuyasu technique for immunogold labelling of sections from aldehyde-fixed samples. The difference of this method with the original Tokuyasu technique is that the immuno-labelled sections are stabilized in a thin layer of vitreous water by plunge-freezing prior to electron microscopical observation. The vitrification step allows for phase contrast-based imaging at cryogenic conditions. We show that this immuno-labelling method is well-suited for imaging cellular ultrastructure in three dimensions (tomography) at cryogenic conditions, and that fluorescence associated with the sections is retained. This method is a valuable tool for Correlative Light and Electron Microscopy (CLEM), and we refer to this method in combination with CLEM as VOS (vitrification of sections). We provide examples for the application of VOS using dendritic cells and neurons, and show specifically that this method enables the researcher to navigate to lysosomes and synapses.





    Categories: Journal Articles
  • Crystal structure of the extracellular juxtamembrane region of Robo1
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2

    Author(s): Reut Barak , Roxane Lahmi , Lada Gevorkyan-Airapetov , Eliad Levy , Amit Tzur , Yarden Opatowsky

    Robo receptors play pivotal roles in neurodevelopment, and their deregulation is implicated in several neuropathological conditions and cancers. To date, the mechanism of Robo activation and regulation remains obscure. Here we present the crystal structure of the juxtamembrane (JM) domains of human Robo1. The structure exhibits unexpectedly high backbone similarity to the netrin and RGM binding region of neogenin and DCC, which are functionally related receptors of Robo1. Comparison of these structures reveals a conserved surface that overlaps with a cluster of oncogenic and neuropathological mutations found in all Robo isoforms. The structure also reveals the intricate folding of the JM linker, which points to its role in Robo1 activation. Further experiments with cultured cells demonstrate that exposure or relief of the folded JM linker results in enhanced shedding of the Robo1 ectodomain.





    Categories: Journal Articles
  • Crystallinity and microchemistry of Nassarius reticulatus (Caenogastropoda) statoliths: Towards their structure stability and homogeneity
    [Jun 2014]

    Publication date: May 2014
    Source:Journal of Structural Biology, Volume 186, Issue 2

    Author(s): Susana Galante-Oliveira , Raquel Marçal , Fernanda Guimarães , Jorge Soares , José Carlos Lopes , Jorge Machado , Carlos Barroso

    Gastropod statoliths are spherical biocarbonates formed during their lifespan. The stability and homogeneity of these structures’ mineral matrix was characterised along their radiuses, using Nassarius reticulatus as a model. Generally, they were proved to be bimineralic. Two of the three CaCO3 crystalline polymorphs occurring in biocarbonates – aragonite and calcite – coexist along statolith radiuses, aragonite being unequivocally the most abundant phase. The presence of a diffuse organic matrix was also perceived by the detection of a weak Raman band between 2800 and 3000cm−1 consistently observed along radiuses. Beyond the apparent stability and homogeneity, different crystalline orientations were disclosed by Raman spectroscopy. A change in the intensity pattern of the features related to the lattice and bending modes of aragonite between different radiuses give new insights for a possible spherulitic-like growth of these structures. As expected from the relative homogeneity of both mineral and organic signals, there was no pattern on the distribution of Ca, O, Na and S along radiuses. However, a higher concentration of Sr occurs in growth rings (known as winter tags), corroborating the already described negative correlation between the concentration of this element in statoliths and temperature. Despite the apparent stability and homogeneity of the matrix during its lifespan, the periodic distribution of Sr potentially influences a dissimilar incorporation of trace elements in increments and growth rings. Since gastropod statolith elemental fingerprinting was recently suggested as a new tool to monitor marine environmental changes, the pressing need for further studies on the incorporation of traces in these structures is highlighted.





    Categories: Journal Articles
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