1
|
Skeffington A, Fischer A, Sviben S, Brzezinka M, Górka M, Bertinetti L, Woehle C, Huettel B, Graf A, Scheffel A. A joint proteomic and genomic investigation provides insights into the mechanism of calcification in coccolithophores. Nat Commun 2023; 14:3749. [PMID: 37353496 PMCID: PMC10290126 DOI: 10.1038/s41467-023-39336-1] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 06/05/2023] [Indexed: 06/25/2023] Open
Abstract
Coccolithophores are globally abundant, calcifying microalgae that have profound effects on marine biogeochemical cycles, the climate, and life in the oceans. They are characterized by a cell wall of CaCO3 scales called coccoliths, which may contribute to their ecological success. The intricate morphologies of coccoliths are of interest for biomimetic materials synthesis. Despite the global impact of coccolithophore calcification, we know little about the molecular machinery underpinning coccolithophore biology. Working on the model Emiliania huxleyi, a globally distributed bloom-former, we deploy a range of proteomic strategies to identify coccolithogenesis-related proteins. These analyses are supported by a new genome, with gene models derived from long-read transcriptome sequencing, which revealed many novel proteins specific to the calcifying haptophytes. Our experiments provide insights into proteins involved in various aspects of coccolithogenesis. Our improved genome, complemented with transcriptomic and proteomic data, constitutes a new resource for investigating fundamental aspects of coccolithophore biology.
Collapse
Affiliation(s)
- Alastair Skeffington
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Axel Fischer
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Sanja Sviben
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Magdalena Brzezinka
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Michał Górka
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Luca Bertinetti
- Max Planck Institute of Colloids and Interfaces, Potsdam-Golm, 14476, Germany
| | - Christian Woehle
- Max Planck Institute for Plant Breeding Research, Max Planck-Genome-Centre Cologne, Cologne, 50829, Germany
| | - Bruno Huettel
- Max Planck Institute for Plant Breeding Research, Max Planck-Genome-Centre Cologne, Cologne, 50829, Germany
| | - Alexander Graf
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - André Scheffel
- Technische Universität Dresden, Faculty of Biology, 01307, Dresden, Germany.
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany.
| |
Collapse
|
2
|
Silvestri A, Pätzold J, Fratzl P, Scheffel A, Faivre D. Surface-Enhanced Raman Scattering Microspectroscopy Enables the Direct Characterization of Biomineral-Associated Organic Material on Single Calcareous Microskeletons. J Phys Chem Lett 2020; 11:8623-8629. [PMID: 32960608 PMCID: PMC7584362 DOI: 10.1021/acs.jpclett.0c02041] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/22/2020] [Indexed: 05/24/2023]
Abstract
Biominerals are composite materials with inorganic and organic components. The latter provide insights into how organisms control mineralization and, if derived from micro/nannofossils, into past climates. Many calcifying organisms cannot be cultured or are extinct; the only materials available for their study are therefore complex environmental samples in which the organism of interest may only be a minor component. There is currently no method for characterizing the biomineral-associated organic material from single particles within such assemblages, so its compositional diversity is unknown. Focusing on coccoliths, we demonstrate that surface-enhanced Raman scattering microspectroscopy can be used to determine the origin and composition of fossil organic matter at the single-particle level in a heterogeneous micro/nannofossil assemblage. This approach may find applications in the study of micro/nannofossil assemblages and uncultivated species, providing evolutionary insights into the macromolecular repertoire involved in biomineralization.
Collapse
Affiliation(s)
- Alessandro Silvestri
- Max
Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany
- Max
Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Jürgen Pätzold
- University
of Bremen, MARUM-Center for
Marine Environmental Sciences, 28359 Bremen, Germany
| | - Peter Fratzl
- Max
Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - André Scheffel
- Max
Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Damien Faivre
- Max
Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany
- Aix-Marseille
Université, CEA, CNRS, BIAM, 13108 Saint Paul lez Durance, France
| |
Collapse
|
3
|
Hartmann S, Preick M, Abelt S, Scheffel A, Hofreiter M. Annotated genome sequences of the carnivorous plant Roridula gorgonias and a non-carnivorous relative, Clethra arborea. BMC Res Notes 2020; 13:426. [PMID: 32912303 PMCID: PMC7488092 DOI: 10.1186/s13104-020-05254-4] [Citation(s) in RCA: 2] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 08/24/2020] [Indexed: 11/21/2022] Open
Abstract
Objective Plant carnivory is distributed across the tree of life and has evolved at least six times independently, but sequenced and annotated nuclear genomes of carnivorous plants are currently lacking. We have sequenced and structurally annotated the nuclear genome of the carnivorous Roridula gorgonias and that of a non-carnivorous relative, Madeira’s lily-of-the-valley-tree, Clethra arborea, both within the Ericales. This data adds an important resource to study the evolutionary genetics of plant carnivory across angiosperm lineages and also for functional and systematic aspects of plants within the Ericales. Results Our assemblies have total lengths of 284 Mbp (R. gorgonias) and 511 Mbp (C. arborea) and show high BUSCO scores of 84.2% and 89.5%, respectively. We used their predicted genes together with publicly available data from other Ericales’ genomes and transcriptomes to assemble a phylogenomic data set for the inference of a species tree. However, groups of orthologs showed a marked absence of species represented by a transcriptome. We discuss possible reasons and caution against combining predicted genes from genome- and transriptome-based assemblies.
Collapse
Affiliation(s)
- Stefanie Hartmann
- Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany.
| | - Michaela Preick
- Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Silke Abelt
- Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - André Scheffel
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam, Germany
| | - Michael Hofreiter
- Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| |
Collapse
|
4
|
Skeffington AW, Grimm A, Schönefeld S, Petersen K, Scheffel A. An Efficient Method for the Plating of Haploid and Diploid Emiliania huxleyi on Solid Medium 1. J Phycol 2020; 56:238-242. [PMID: 31657459 DOI: 10.1111/jpy.12942] [Citation(s) in RCA: 2] [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: 06/06/2019] [Accepted: 10/10/2019] [Indexed: 06/10/2023]
Abstract
Emiliania huxleyi is a globally important coccolithophore and one of the most successful eukaryotic organisms in the modern oceans. Despite a large body of work on this organism, including the sequencing of its genome, the tools required for forward and reverse functional genetic studies are still undeveloped. Here we present an optimized method for the clonal isolation of E. huxleyi by plating on solid medium. We demonstrate the utility of this method for a variety of strains including haploid, calcifying-diploid, and noncalcifying diploid strains. We show that, in contrast to previous studies, no changes in cell ploidy status occur when the cells are plated. Our method will greatly aid attempts to elucidate the genetic basis of the remarkable physiology of E. huxleyi by forward and reverse genetic approaches.
Collapse
Affiliation(s)
- Alastair W Skeffington
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, D-14476, Potsdam-Golm, Germany
| | - Annett Grimm
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, D-14476, Potsdam-Golm, Germany
| | - Steffi Schönefeld
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, D-14476, Potsdam-Golm, Germany
| | - Kerstin Petersen
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, D-14476, Potsdam-Golm, Germany
| | - André Scheffel
- Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, D-14476, Potsdam-Golm, Germany
| |
Collapse
|
5
|
Gal A, Wirth R, Barkay Z, Eliaz N, Scheffel A, Faivre D. Templated and self-limiting calcite formation directed by coccolith organic macromolecules. Chem Commun (Camb) 2018. [PMID: 28649685 DOI: 10.1039/c7cc03639f] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The formation of intricately shaped crystalline minerals by organisms is orchestrated by specialized biomacromolecules. The macromolecules associated with coccoliths, nanometer-sized calcite crystal arrays produced by marine microalgae, can form a distinct calcium-rich phase via macromolecular recognition. Here, we show that this calcium-rich phase can be mineralized into a thin film of single-crystalline calcite by the balanced addition of carbonate ions. Such a crystallization process provides a strategy to direct crystalline products via local interactions between soluble macromolecules and compatible templates.
Collapse
Affiliation(s)
- Assaf Gal
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany
| | | | | | | | | | | |
Collapse
|
6
|
Skeffington AW, Scheffel A. Exploiting algal mineralization for nanotechnology: bringing coccoliths to the fore. Curr Opin Biotechnol 2018; 49:57-63. [DOI: 10.1016/j.copbio.2017.07.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 07/21/2017] [Accepted: 07/25/2017] [Indexed: 12/17/2022]
|
7
|
Gal A, Sviben S, Wirth R, Schreiber A, Lassalle‐Kaiser B, Faivre D, Scheffel A. Trace-Element Incorporation into Intracellular Pools Uncovers Calcium-Pathways in a Coccolithophore. Adv Sci (Weinh) 2017; 4:1700088. [PMID: 29051853 PMCID: PMC5644232 DOI: 10.1002/advs.201700088] [Citation(s) in RCA: 15] [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] [Received: 02/15/2017] [Revised: 04/23/2017] [Indexed: 05/31/2023]
Abstract
Many organisms form minerals from precursor phases that crystallize under strict biological control. The dynamic intracellular processes of formation, transport, and deposition of these precursor phases are challenging to identify. An unusual situation is recently revealed for the calcifying alga Emiliania huxleyi, as the cells contain a compartment filled with a concentrated Ca and P phase but the final calcite crystals, which are nucleated in a different compartment, are P-free. Thus, the connection of the Ca-P-rich pool to the mineralization process remains unclear. Here, pulse-chase experiments are used with Sr to label the Ca-P-rich phase in E. huxleyi cells, and cryo X-ray absorption spectroscopy and analytical transmission electron microscopy to follow the Sr within cells. It is found that Sr is first found in the Ca-P-rich phase and then becomes incorporated into the calcite. This demonstrates that the calcium used by the cells to build calcite originates from the Ca-P-rich pool.
Collapse
Affiliation(s)
- Assaf Gal
- Max‐Planck Institute of Molecular Plant PhysiologyPotsdam‐Golm14476Germany
- Max‐Planck Institute of Colloids and InterfacesPotsdam‐Golm14476Germany
| | - Sanja Sviben
- Max‐Planck Institute of Molecular Plant PhysiologyPotsdam‐Golm14476Germany
| | | | | | | | - Damien Faivre
- Max‐Planck Institute of Colloids and InterfacesPotsdam‐Golm14476Germany
| | - André Scheffel
- Max‐Planck Institute of Molecular Plant PhysiologyPotsdam‐Golm14476Germany
| |
Collapse
|
8
|
Ishihara H, Moraes TA, Pyl ET, Schulze WX, Obata T, Scheffel A, Fernie AR, Sulpice R, Stitt M. Growth rate correlates negatively with protein turnover in Arabidopsis accessions. Plant J 2017; 91:416-429. [PMID: 28419597 DOI: 10.1111/tpj.13576] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [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: 07/18/2016] [Revised: 03/17/2017] [Accepted: 04/10/2017] [Indexed: 05/22/2023]
Abstract
Previous studies with Arabidopsis accessions revealed that biomass correlates negatively to dusk starch content and total protein, and positively to the maximum activities of enzymes in photosynthesis. We hypothesized that large accessions have lower ribosome abundance and lower rates of protein synthesis, and that this is compensated by lower rates of protein degradation. This would increase growth efficiency and allow more investment in photosynthetic machinery. We analysed ribosome abundance and polysome loading in 19 accessions, modelled the rates of protein synthesis and compared them with the observed rate of growth. Large accessions contained less ribosomes than small accessions, due mainly to cytosolic ribosome abundance falling at night in large accessions. The modelled rates of protein synthesis resembled those required for growth in large accessions, but were up to 30% in excess in small accessions. We then employed 13 CO2 pulse-chase labelling to measure the rates of protein synthesis and degradation in 13 accessions. Small accessions had a slightly higher rate of protein synthesis and much higher rates of protein degradation than large accessions. Protein turnover was negligible in large accessions but equivalent to up to 30% of synthesised protein day-1 in small accessions. We discuss to what extent the decrease in growth in small accessions can be quantitatively explained by known costs of protein turnover and what factors may lead to the altered diurnal dynamics and increase of ribosome abundance in small accessions, and propose that there is a trade-off between protein turnover and maximisation of growth rate.
Collapse
Affiliation(s)
- Hirofumi Ishihara
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Thiago Alexandre Moraes
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Eva-Theresa Pyl
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Waltraud X Schulze
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
- Department of Plant Systems Biology, University of Hohenheim, Garbenstraße 30, Stuttgart, 70599, Germany
| | - Toshihiro Obata
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - André Scheffel
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| | - Ronan Sulpice
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
- Plant Systems Biology Laboratory, Plant and AgriBiosciences Research Centre, Botany and Plant Science, National University of Ireland Galway, Galway, H91 TK33, Ireland
| | - Mark Stitt
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
| |
Collapse
|
9
|
Hood MA, Leemreize H, Scheffel A, Faivre D. Lattice distortions in coccolith calcite crystals originate from occlusion of biomacromolecules. J Struct Biol 2016; 196:147-154. [DOI: 10.1016/j.jsb.2016.09.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 09/08/2016] [Accepted: 09/15/2016] [Indexed: 11/15/2022]
|
10
|
Gal A, Wirth R, Kopka J, Fratzl P, Faivre D, Scheffel A. Macromolecular recognition directs calcium ions to coccolith mineralization sites. Science 2016; 353:590-3. [DOI: 10.1126/science.aaf7889] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/14/2016] [Indexed: 01/16/2023]
|
11
|
Sviben S, Gal A, Hood MA, Bertinetti L, Politi Y, Bennet M, Krishnamoorthy P, Schertel A, Wirth R, Sorrentino A, Pereiro E, Faivre D, Scheffel A. A vacuole-like compartment concentrates a disordered calcium phase in a key coccolithophorid alga. Nat Commun 2016; 7:11228. [PMID: 27075521 PMCID: PMC4834641 DOI: 10.1038/ncomms11228] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 02/25/2016] [Indexed: 02/07/2023] Open
Abstract
Coccoliths are calcitic particles produced inside the cells of unicellular marine
algae known as coccolithophores. They are abundant components of sea-floor
carbonates, and the stoichiometry of calcium to other elements in fossil coccoliths
is widely used to infer past environmental conditions. Here we study cryo-preserved
cells of the dominant coccolithophore Emiliania huxleyi using
state-of-the-art nanoscale imaging and spectroscopy. We identify a compartment,
distinct from the coccolith-producing compartment, filled with high concentrations
of a disordered form of calcium. Co-localized with calcium are high concentrations
of phosphorus and minor concentrations of other cations. The amounts of calcium
stored in this reservoir seem to be dynamic and at a certain stage the compartment
is in direct contact with the coccolith-producing vesicle, suggesting an active role
in coccolith formation. Our findings provide insights into calcium accumulation in
this important calcifying organism. Coccolithophores are unicellular marine algae that produce calcitic
particles inside their cells. Here the authors study cells of the dominant
coccolithophore Emiliania huxleyi and identify an intracellular compartment that
is filled with high concentrations of a disordered form of calcium.
Collapse
Affiliation(s)
- Sanja Sviben
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany
| | - Assaf Gal
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany.,Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany
| | - Matthew A Hood
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany.,Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany
| | - Luca Bertinetti
- Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany
| | - Yael Politi
- Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany
| | - Mathieu Bennet
- Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany
| | | | - Andreas Schertel
- Carl Zeiss Microscopy GmbH, Global Applications Support, Oberkochen 73447, Germany
| | - Richard Wirth
- Department of Geomaterials, GeoForschungsZentrum Potsdam, Potsdam 14473, Germany
| | - Andrea Sorrentino
- ALBA Synchrotron Light Source, Cerdanyola del Vallés, Barcelona 08290, Spain
| | - Eva Pereiro
- ALBA Synchrotron Light Source, Cerdanyola del Vallés, Barcelona 08290, Spain
| | - Damien Faivre
- Department of Biomaterials, Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm 14476, Germany
| | - André Scheffel
- Max-Planck Institute of Molecular Plant Physiology, Potsdam-Golm 14476, Germany
| |
Collapse
|
12
|
Kotzsch A, Pawolski D, Milentyev A, Shevchenko A, Scheffel A, Poulsen N, Shevchenko A, Kröger N. Biochemical Composition and Assembly of Biosilica-associated Insoluble Organic Matrices from the Diatom Thalassiosira pseudonana. J Biol Chem 2015; 291:4982-97. [PMID: 26710847 DOI: 10.1074/jbc.m115.706440] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [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: 11/24/2015] [Indexed: 11/06/2022] Open
Abstract
The nano- and micropatterned biosilica cell walls of diatoms are remarkable examples of biological morphogenesis and possess highly interesting material properties. Only recently has it been demonstrated that biosilica-associated organic structures with specific nanopatterns (termed insoluble organic matrices) are general components of diatom biosilica. The model diatom Thalassiosira pseudonana contains three types of insoluble organic matrices: chitin meshworks, organic microrings, and organic microplates, the latter being described in the present study for the first time. To date, little is known about the molecular composition, intracellular assembly, and biological functions of organic matrices. Here we have performed structural and functional analyses of the organic microrings and organic microplates from T. pseudonana. Proteomics analysis yielded seven proteins of unknown function (termed SiMat proteins) together with five known silica biomineralization proteins (four cingulins and one silaffin). The location of SiMat1-GFP in the insoluble organic microrings and the similarity of tyrosine- and lysine-rich functional domains identifies this protein as a new member of the cingulin protein family. Mass spectrometric analysis indicates that most of the lysine residues of cingulins and the other insoluble organic matrix proteins are post-translationally modified by short polyamine groups, which are known to enhance the silica formation activity of proteins. Studies with recombinant cingulins (rCinY2 and rCinW2) demonstrate that acidic conditions (pH 5.5) trigger the assembly of mixed cingulin aggregates that have silica formation activity. Our results suggest an important role for cingulins in the biogenesis of organic microrings and support the hypothesis that this type of insoluble organic matrix functions in biosilica morphogenesis.
Collapse
Affiliation(s)
| | | | - Alexander Milentyev
- the Max-Planck-Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany, and
| | - Anna Shevchenko
- the Max-Planck-Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany, and
| | - André Scheffel
- the Max-Planck-Institute of Plant Physiology, 14476 Potsdam, Germany
| | | | - Andrej Shevchenko
- the Max-Planck-Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany, and
| | - Nils Kröger
- From the B CUBE Center for Molecular Bioengineering and the Department of Chemistry and Food Chemistry, Technische Universität Dresden, 01307 Dresden, Germany,
| |
Collapse
|
13
|
|
14
|
Poulsen N, Scheffel A, Sheppard VC, Chesley PM, Kröger N. Pentalysine clusters mediate silica targeting of silaffins in Thalassiosira pseudonana. J Biol Chem 2013; 288:20100-9. [PMID: 23720751 DOI: 10.1074/jbc.m113.469379] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The biological formation of inorganic materials (biomineralization) often occurs in specialized intracellular vesicles. Prominent examples are diatoms, a group of single-celled eukaryotic microalgae that produce their SiO2 (silica)-based cell walls within intracellular silica deposition vesicles (SDVs). SDVs contain protein-based organic matrices that control silica formation, resulting in species specifically nanopatterned biosilica, an organic-inorganic composite material. So far no information is available regarding the molecular mechanisms of SDV biogenesis. Here we have investigated by fluorescence microscopy and subcellular membrane fractionation the intracellular transport of silaffin Sil3. Silaffins are a group of phosphoproteins constituting the main components of the organic matrix of diatom biosilica. We demonstrate that the N-terminal signal peptide of Sil3 mediates import into a specific subregion of the endoplasmic reticulum. Additional segments from the mature part of Sil3 are required to reach post-endoplasmic reticulum compartments. Further transport of Sil3 and incorporation into the biosilica (silica targeting) require protein segments that contain a high density of modified lysine residues and phosphoserines. Silica targeting of Sil3 is not dependent on a particular peptide sequence, yet a lysine-rich 12-14-amino acid peptide motif (pentalysine cluster), which is conserved in all silaffins, strongly promotes silica targeting. The results of the present work provide the first insight into the molecular mechanisms for biogenesis of mineral-forming vesicles from an eukaryotic organism.
Collapse
|
15
|
Katzmann E, Scheffel A, Gruska M, Plitzko JM, Schüler D. Loss of the actin-like protein MamK has pleiotropic effects on magnetosome formation and chain assembly in Magnetospirillum gryphiswaldense. Mol Microbiol 2010; 77:208-24. [PMID: 20487281 DOI: 10.1111/j.1365-2958.2010.07202.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Magnetotactic bacteria synthesize magnetosomes, which are unique organelles consisting of membrane-enclosed magnetite crystals. For magnetic orientation individual magnetosome particles are assembled into well-organized chains. The actin-like MamK and the acidic MamJ proteins were previously implicated in chain assembly. While MamK was suggested to form magnetosome-associated cytoskeletal filaments, MamJ is assumed to attach the magnetosome vesicles to these structures. Although the deletion of either mamK in Magnetospirillum magneticum, or mamJ in Magnetospirillum gryphiswaldense affected chain formation, the previously observed phenotypes were not fully consistent, suggesting different mechanisms of magnetosome chain assembly in both organisms. Here we show that in M. gryphiswaldense MamK is not absolutely required for chain formation. Straight chains, albeit shorter, fragmented and ectopic, were still formed in a mamK deletion mutant, although magnetosome filaments were absent as shown by cryo-electron tomography. Loss of MamK also resulted in reduced numbers of magnetite crystals and magnetosome vesicles and led to the mislocalization of MamJ. In addition, extensive analysis of wild type and mutant cells revealed previously unidentified ultrastructural characteristics in M. gryphiswaldense. Our results suggest that, despite of their functional equivalence, loss of MamK proteins in different bacteria may result in distinct phenotypes, which might be due to a species-specific genetic context.
Collapse
Affiliation(s)
- Emanuel Katzmann
- Ludwig-Maximillians-Universität München, Department Biologie I, Bereich Mikrobiologie, Biozentrum der LMU, D-82152 Martinsried, Germany
| | | | | | | | | |
Collapse
|
16
|
Scheffel A, Schüler D. The acidic repetitive domain of the Magnetospirillum gryphiswaldense MamJ protein displays hypervariability but is not required for magnetosome chain assembly. J Bacteriol 2007; 189:6437-46. [PMID: 17601786 PMCID: PMC1951895 DOI: 10.1128/jb.00421-07] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Magnetotactic bacteria navigate along the earth's magnetic field using chains of magnetosomes, which are intracellular organelles comprising membrane-enclosed magnetite crystals. The assembly of highly ordered magnetosome chains is under genetic control and involves several specific proteins. Based on genetic and cryo-electron tomography studies, a model was recently proposed in which the acidic MamJ magnetosome protein attaches magnetosome vesicles to the actin-like cytoskeletal filament formed by MamK, thereby preventing magnetosome chains from collapsing. However, the exact functions as well as the mode of interaction between MamK and MamJ are unknown. Here, we demonstrate that several functional MamJ variants from Magnetospirillum gryphiswaldense and other magnetotactic bacteria share an acidic and repetitive central domain, which displays an unusual intra- and interspecies sequence polymorphism, probably caused by homologous recombination between identical copies of Glu- and Pro-rich repeats. Surprisingly, mamJ mutant alleles in which the central domain was deleted retained their potential to restore chain formation in a DeltamamJ mutant, suggesting that the acidic domain is not essential for MamJ's function. Results of two-hybrid experiments indicate that MamJ physically interacts with MamK, and two distinct sequence regions within MamJ were shown to be involved in binding to MamK. Mutant variants of MamJ lacking either of the binding domains were unable to functionally complement the DeltamamJ mutant. In addition, two-hybrid experiments suggest both MamK-binding domains of MamJ confer oligomerization of MamJ. In summary, our data reveal domains required for the functions of the MamJ protein in chain assembly and maintenance and provide the first experimental indications for a direct interaction between MamJ and the cytoskeletal filament protein MamK.
Collapse
Affiliation(s)
- André Scheffel
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | | |
Collapse
|
17
|
Dalisay DS, Webb JS, Scheffel A, Svenson C, James S, Holmström C, Egan S, Kjelleberg S. A mannose-sensitive haemagglutinin (MSHA)-like pilus promotes attachment of Pseudoalteromonas tunicata cells to the surface of the green alga Ulva australis. Microbiology (Reading) 2006; 152:2875-2883. [PMID: 17005969 DOI: 10.1099/mic.0.29158-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This study demonstrates that attachment of the marine bacterium Pseudoalteromonas tunicata to the cellulose-containing surface of the green alga Ulva australis is mediated by a mannose-sensitive haemagglutinin (MSHA-like) pilus. We have identified an MSHA pilus biogenesis gene locus in P. tunicata, termed mshI1I2JKLMNEGFBACDOPQ, which shows significant homology, with respect to its genetic characteristics and organization, to the MSHA pilus biogenesis gene locus of Vibrio cholerae. Electron microscopy studies revealed that P. tunicata wild-type cells express flexible pili peritrichously arranged on the cell surface. A P. tunicata mutant (SM5) with a transposon insertion in the mshJ region displayed a non-piliated phenotype. Using SM5, it has been demonstrated that the MSHA pilus promotes attachment of P. tunicata wild-type cells in polystyrene microtitre plates, as well as to microcrystalline cellulose and to the living surface of U. australis. P. tunicata also demonstrated increased pilus production in response to cellulose and its monomer constituent cellobiose. The MSHA pilus thus functions as a determinant of attachment in P. tunicata, and it is proposed that an understanding of surface sensing mechanisms displayed by P. tunicata will provide insight into specific ecological interactions that occur between this bacterium and higher marine organisms.
Collapse
MESH Headings
- Bacterial Adhesion/genetics
- Bacterial Proteins/genetics
- Cellulose/metabolism
- DNA Transposable Elements
- DNA, Bacterial/chemistry
- DNA, Bacterial/genetics
- Fimbriae Proteins/genetics
- Fimbriae Proteins/metabolism
- Fimbriae Proteins/physiology
- Fimbriae, Bacterial/genetics
- Fimbriae, Bacterial/physiology
- Fimbriae, Bacterial/ultrastructure
- Gene Deletion
- Gene Expression Regulation, Bacterial
- Mannose/metabolism
- Mannose-Binding Lectin/genetics
- Mannose-Binding Lectin/metabolism
- Mannose-Binding Lectin/physiology
- Microscopy, Electron, Transmission
- Microscopy, Fluorescence
- Molecular Sequence Data
- Multigene Family
- Mutagenesis, Insertional
- Polystyrenes/metabolism
- Pseudoalteromonas/genetics
- Pseudoalteromonas/physiology
- Sequence Analysis, DNA
- Ulva/microbiology
Collapse
Affiliation(s)
- Doralyn S Dalisay
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Jeremy S Webb
- Centre for Marine Biofouling and Bio-innovation, University of New South Wales, Sydney, NSW 2052, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - André Scheffel
- Max-Planck-Institute for Marine Microbiology, Celsiusstraße 1 28359, Bremen, Germany
| | - Charles Svenson
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Sally James
- Centre for Marine Biofouling and Bio-innovation, University of New South Wales, Sydney, NSW 2052, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Carola Holmström
- Centre for Marine Biofouling and Bio-innovation, University of New South Wales, Sydney, NSW 2052, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Suhelen Egan
- Centre for Marine Biofouling and Bio-innovation, University of New South Wales, Sydney, NSW 2052, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Staffan Kjelleberg
- Centre for Marine Biofouling and Bio-innovation, University of New South Wales, Sydney, NSW 2052, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| |
Collapse
|
18
|
Scheffel A, Gruska M, Faivre D, Linaroudis A, Plitzko JM, Schüler D. An acidic protein aligns magnetosomes along a filamentous structure in magnetotactic bacteria. Nature 2005; 440:110-4. [PMID: 16299495 DOI: 10.1038/nature04382] [Citation(s) in RCA: 316] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2005] [Accepted: 10/28/2005] [Indexed: 11/09/2022]
Abstract
Magnetotactic bacteria are widespread aquatic microorganisms that use unique intracellular organelles to navigate along the Earth's magnetic field. These organelles, called magnetosomes, consist of membrane-enclosed magnetite crystals that are thought to help to direct bacterial swimming towards growth-favouring microoxic zones at the bottom of natural waters. Questions in the study of magnetosome formation include understanding the factors governing the size and redox-controlled synthesis of the nano-sized magnetosomes and their assembly into a regular chain in order to achieve the maximum possible magnetic moment, against the physical tendency of magnetosome agglomeration. A deeper understanding of these mechanisms is expected from studying the genes present in the identified chromosomal 'magnetosome island', for which the connection with magnetosome synthesis has become evident. Here we use gene deletion in Magnetospirillum gryphiswaldense to show that magnetosome alignment is coupled to the presence of the mamJ gene product. MamJ is an acidic protein associated with a novel filamentous structure, as revealed by fluorescence microscopy and cryo-electron tomography. We suggest a mechanism in which MamJ interacts with the magnetosome surface as well as with a cytoskeleton-like structure. According to our hypothesis, magnetosome architecture represents one of the highest structural levels achieved in prokaryotic cells.
Collapse
Affiliation(s)
- André Scheffel
- Max Planck Institute for Marine Microbiology, Celsiusstr. 1, D-28359 Bremen, Germany
| | | | | | | | | | | |
Collapse
|
19
|
Schübbe S, Kube M, Scheffel A, Wawer C, Heyen U, Meyerdierks A, Madkour MH, Mayer F, Reinhardt R, Schüler D. Characterization of a spontaneous nonmagnetic mutant of Magnetospirillum gryphiswaldense reveals a large deletion comprising a putative magnetosome island. J Bacteriol 2003; 185:5779-90. [PMID: 13129949 PMCID: PMC193972 DOI: 10.1128/jb.185.19.5779-5790.2003] [Citation(s) in RCA: 171] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Frequent spontaneous loss of the magnetic phenotype was observed in stationary-phase cultures of the magnetotactic bacterium Magnetospirillum gryphiswaldense MSR-1. A nonmagnetic mutant, designated strain MSR-1B, was isolated and characterized. The mutant lacked any structures resembling magnetosome crystals as well as internal membrane vesicles. The growth of strain MSR-1B was impaired under all growth conditions tested, and the uptake and accumulation of iron were drastically reduced under iron-replete conditions. A large chromosomal deletion of approximately 80 kb was identified in strain MSR-1B, which comprised both the entire mamAB and mamDC clusters as well as further putative operons encoding a number of magnetosome-associated proteins. A bacterial artificial chromosome clone partially covering the deleted region was isolated from the genomic library of wild-type M. gryphiswaldense. Sequence analysis of this fragment revealed that all previously identified mam genes were closely linked with genes encoding other magnetosome-associated proteins within less than 35 kb. In addition, this region was remarkably rich in insertion elements and harbored a considerable number of unknown gene families which appeared to be specific for magnetotactic bacteria. Overall, these findings suggest the existence of a putative large magnetosome island in M. gryphiswaldense and other magnetotactic bacteria.
Collapse
Affiliation(s)
- Sabrina Schübbe
- Max-Planck-Institut für Marine Mikrobiologie, 28359 Bremen, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Scheffel A, Kramer B. Electric signals in the social behavior of sympatric elephantfish (Mormyridae, Teleostei) from the upper Zambezi River. Naturwissenschaften 2000; 87:142-7. [PMID: 10798201 DOI: 10.1007/s001140050693] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Electrocommunication in mormyrid fish from African freshwaters is a challenging research field in neuroethology (Turner et al. 1999). However, virtually nothing is known about electrocommunication within natural mormyrid populations involving sympatric, syntopic species. Here we report on the nocturnal activities and electrocommunication among three syntopic species in a spacious laboratory setting resembling the natural one. Petrocephalus catostoma, Cyphomyrus discorhynchus, and Hippopotamyrus sp. nov. differ characteristically in their behavior, such as in territorial defense, schooling, and joining members of other species during foraging. Comparing social encounters within and between species, the first evidence for interspecific electrocommunication among syntopic species was found.
Collapse
Affiliation(s)
- A Scheffel
- Zoologisches Institut, Universität Regensburg, Germany
| | | |
Collapse
|
21
|
Kłoszewska I, Scheffel A. [Aggressive behavior of psychiatric patients among geriatric population]. Psychiatr Pol 1998; 32:423-31. [PMID: 9816900] [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] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Medical documentation of 674 elderly patients of gerontopsychiatric department was studied in order to estimate the frequency of physical aggression in relation to sex, diagnosis of dementia and other psychiatric disorders. This form of aggression was found significantly more often in men (52%) than in women (32%). The prevalence of aggression in men was even more evident in the dementia group (67% men and 39% women). Aggressive acts, with the use of objects as weapons, were aimed mainly against other patients when carried out by women, while male patients more often used the objects to attack the staff. None of the 118 aggressive women injured the attacked person, but 7% of the 160 aggressive men did. The aggression of sexual nature was observed in men (5%) only.
Collapse
Affiliation(s)
- I Kłoszewska
- II Kliniki Psychiatrycznej Akademii Medycznej w Lodzi
| | | |
Collapse
|
22
|
Abstract
Falling is an everyday risk for elderly people, with the consequence of getting hurt. What exactly the dangers are, especially in people with gerontopsychiatric disorders, has hardly ever been mentioned in today's literature. Therefore this report deals with 887 documented fall cases in 758 gerontopsychiatric inpatients during a cumulative time period of 3845 months. The consequences of the falls according to sex and diagnosis of dementia were divided in four categories, depending on how serious the injuries were. About 65 to 71% of the patients don't show any direct consequences, about 10% have serious injuries of which 5% are fractures. There are significantly more dement women than dement men who suffer from fractures. Women over eighty years have significantly fewer serious fall injuries than women in their eighties; the same phenomenon can be observed in men concerning light injuries.
Collapse
Affiliation(s)
- A Scheffel
- Abteilung Gerontopsychiatrie, Rheinische Landesklinik Bedburg-Hau
| | | |
Collapse
|
23
|
Beanlands RS, deKemp R, Scheffel A, Nahmias C, Garnett ES, Coates G, Johansen HL, Fallen E. Can nitrogen-13 ammonia kinetic modeling define myocardial viability independent of fluorine-18 fluorodeoxyglucose? J Am Coll Cardiol 1997; 29:537-43. [PMID: 9060890 DOI: 10.1016/s0735-1097(96)00561-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVES The hypothesis of this study was that evaluation of myocardial flow and metabolism using nitrogen-13 (N-13) ammonia kinetic modeling with dynamic positron emission tomographic (PET) imaging could identify regions of myocardial scar and viable myocardium as defined by fluorine-18 fluorodeoxyglucose (F-18 FDG) PET. BACKGROUND Uptake of most perfusion tracers depends on both perfusion and metabolic retention in tissue. This characteristic has limited their ability to differentiate myocardial scar from viable tissue. The kinetic modeling of N-13 ammonia permits quantification of blood flow and separation of the metabolic component of its uptake, which may permit differentiation of scar from viable tissue. METHODS Sixteen patients, > 3 months after myocardial infarction, underwent dynamic N-13 ammonia and F-18 FDG PET imaging. Regions of reduced and normal perfusion were defined on static N-13 ammonia images. Patients were classified into two groups (group I [ischemic viable], n = 6; group II [scar], n = 10) on the basis of percent of maximal F-18 FDG uptake in hypoperfused segments. Nitrogen-13 ammonia kinetic modeling was applied to dynamic PET data, and rate constants were determined. Flow was defined by K1; volume of distribution (VD = K1/k2) of N-13 ammonia was used as an indirect indication of metabolic retention. RESULTS Fluorine-18 FDG uptake was reduced in patients with scar compared with normal patients with ischemic viable zones (ischemic viable 93 +/- 27% [mean +/- SD]; scar 37 +/- 16%, p < or = 0.01). Using N-13 ammonia kinetic modeling, flow and VD were reduced in the hypoperfused regions of patients with scar (ischemic viable flow: 0.65 +/- 0.20 ml/min per g, scar: 0.36 +/- 0.16 ml/min per g, p < or = 0.01; VD: 3.9 +/- 1.3 and 2.0 +/- 1.07 ml/g, respectively, p < or = 0.01). For detection of viable myocardium in these patients, the sensitivity and specificity were 100% and 80% for N-13 ammonia PET flow > 0.45 ml/min per g; 100% and 70% for VD > 2.0 ml/g; and 100% and 90% for both flow > 0.45 ml/min per g and VD > 2.0 ml/g, respectively. The positive and negative predictive values for the latter approach were 86% and 100%, respectively. CONCLUSIONS In this cohort, patients having regions with flow < or = 0.45 ml/min per g or VD < or = 2.0 ml/g had scar. Viable myocardium had both flow > 0.45 ml/min per g and VD > 2.0 ml/g. Nitrogen-13 ammonia kinetic modeling permits determination of blood flow and metabolic integrity in patients with previous myocardial infarction and can help differentiate between scar and ischemic but viable myocardium.
Collapse
Affiliation(s)
- R S Beanlands
- Division of Cardiology, E. S. Garnett Medical Imaging Research Centre, McMaster University Medical Centre, Ottawa, Ontario, Canada
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Scheffel A. [Aggression in elderly persons with psychiatric disorders]. Psychiatr Pol 1997; 31:111-20. [PMID: 9527649] [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] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In recent years aggression among elderly patients with psychiatric disorders has become an area of scientific research. A review of 19 reports, mostly from the USA, shows that a great part of these people demonstrate aggression of varied intensity. It is often a very serious problem for family members and a reason for psychiatric admissions. The aggression-index in this population varies depending on the place of living from 14% in the community, 12%-48% in adult homes to more than 60% in psychiatric hospitals. Nearly half of demented patients show aggressive behaviour in different situations, often of extreme intensity. Some reports suggest aggression to be more common among men, but perhaps only in association with dementia.
Collapse
Affiliation(s)
- A Scheffel
- Oddział Gerontopsychiatrii Rheinische Landesklinik Bedburg-Hau, Niemcy
| |
Collapse
|
25
|
Scheffel A. [Serum cholesterol, triglycerides, HDL and LDL in aggressive elderly patients with dementia]. Psychiatr Pol 1996; 30:159-70. [PMID: 8722248] [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] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Associations were analysed between serum concentrations of cholesterol, triglycerides, HDL and LDL measured after hospital admission, and physical aggression in a sample of elderly patients with dementia (210 women and 160 men). A significant lower serum cholesterol and LDL concentration were found in aggressive patients of both sexes and a significant lower serum triglycerides only in aggressive women. In the subgroups of Alzheimer type dementia, women showed significant lower serum triglycerides, and aggressive men significant lower LDL concentration compared with non-aggressive controls. There were no significant differences in serum HDL between aggressive and non-aggressive patients.
Collapse
Affiliation(s)
- A Scheffel
- Z Oddziału Gerontopsychiatrii, Rheinische Landesklinik, Bedburg-Hau, Niemcy
| |
Collapse
|
26
|
Coates G, Chirakal R, Fallen EL, Firnau G, Garnett ES, Kamath MV, Scheffel A, Nahmias C. Regional distribution and kinetics of [18F]6-flurodopamine as a measure of cardiac sympathetic activity in humans. Heart 1996; 75:29-34. [PMID: 8624867 PMCID: PMC484217 DOI: 10.1136/hrt.75.1.29] [Citation(s) in RCA: 11] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
OBJECTIVES To determine whether an increase in cardiac sympathetic activity produced by exercise or sublingual glyceryl trinitrate causes an increased rate of loss of fluorine-18 from the myocardium after intravenous [18F]6-fluorodopamine ([18F]F-DA) in normal volunteers. In addition, to determine the contribution of non-specific uptake of [18F]F-DA in the myocardium in patients with recent heart transplant. PROTOCOL [18F]F was prepared by direct electrophilic fluorination of dopamine. Nine healthy volunteers each received 1.85 x 10(8) Bq (168-250 micrograms) [18F]F-DA over a period of 3 min and were scanned for 2 h in an ECAT 953/31 tomograph. Three controls were scanned before and after vigorous cycle exercise and two were scanned before and after sublingual glyceryl trinitrate. In addition, two patients (1 and 2 years post-heart transplant) underwent a myocardial perfusion study with ammonia labelled with nitrogen-13 followed by an [18F]F-DA study. RESULTS There was intense uniform uptake of [18F]F-DA throughout the myocardium in the healthy volunteers. The time course of 18F in the myocardium under resting conditions fitted a biexponential function with mean half-times of 8.0 and 109 min. Vigorous exercise produced a three to fivefold increase in the rate of loss of 18F compared with that when resting. After glyceryl trinitrate, one control had a profound reduction in blood pressure (23%) and twofold increase in the rate of loss of myocardial 18F. The other control had no physiologically significant change in blood pressure, heart rate, or rate of loss of myocardial 18F. Uptake of [18F]F-DA in the two posttransplant patients was confined to a small anterobasal region adjacent to the atrioventricular groove, while blood flow, as measured with [13N] ammonia, was uniformly distributed throughout the myocardium. Partial reinnervation of the myocardium was confirmed by the presence of distinct low frequency spectral peaks of the heart rate power spectrum in both patients. CONCLUSIONS These results suggest that the uptake of [18F]F-DA reflects the distribution of cardiac sympathetic innervation and that the rate of loss of 18F from the myocardium partially reflects spill over of noradrenaline. The technique may be useful in investigating various cardiac conditions in which the sympathetic system is compromised.
Collapse
Affiliation(s)
- G Coates
- Department of Radiology and Nuclear Medicine, Chedoke-McMaster Hospitals and Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Fallen EL, Nahmias C, Scheffel A, Coates G, Beanlands R, Garnett ES. Redistribution of myocardial blood flow with topical nitroglycerin in patients with coronary artery disease. Circulation 1995; 91:1381-8. [PMID: 7867177 DOI: 10.1161/01.cir.91.5.1381] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Unlike nonselective coronary vasodilators, nitroglycerin (GTN) is said to exert its primary vasodilatory effect on epicardial conductance vessels. Thus, in experimental models of coronary occlusion GTN appears to preferentially direct blood flow to poststenotic zones of ischemia. This phenomenon has, to date, not been tested in humans. Using positron emission tomography we examined the effect of transdermal GTN on global and regional myocardial perfusion in patients with angiographically proven coronary artery disease. METHODS AND RESULTS Myocardial perfusion with [13N]ammonia was estimated from dynamic time-activity curves at baseline and 3 hours following application of either a 0.4 mg/h GTN skin patch (n = 10) or a placebo patch (n = 10) in a double-blind parallel design. From resliced cross-sectional images, regional flow, expressed as [13N]ammonia retention, was estimated from 216 myocardial sectors. Ischemia was defined as a significant reduction (> 2 SDs from average counts/pixel in maximally perfused zones) in [13N]ammonia retention within 10 contiguous myocardial sectors coupled with an increase or no change in counts derived from [18F]fluorodeoxyglucose. There was no change in global myocardial blood flow as expressed by [13N]ammonia retention following either placebo (0.61 +/- 0.14 to 0.62 +/- 0.12 min-1) or GTN (0.75 +/- 0.22 to 0.74 +/- 0.19 min-1). Conversely, there was a significant increase in the proportion of blood flow to the ischemic zones with GTN (73.9 +/- 12.6% to 94.9 +/- 17.8%; P < .05). No change in the distribution of blood flow to either ischemic or nonischemic zones was observed with placebo. A slight but insignificant decrease in [13N]ammonia retention in nonischemic zones was observed with GTN (1.01 +/- 0.31 to 0.93 +/- 0.26 min-1). CONCLUSIONS This study suggests that under resting conditions topical GTN alters myocardial perfusion by preferentially increasing flow to areas of reduced perfusion with little or no change in global myocardial perfusion in patients whose angina is responsive to GTN.
Collapse
Affiliation(s)
- E L Fallen
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | | | | | | | | | | |
Collapse
|
28
|
Affiliation(s)
- E S Garnett
- Department of Nuclear Medicine, McMaster University Medical Centre, Chedoke-McMaster Hospitals, Hamilton, Ontario, Canada
| | | | | | | | | |
Collapse
|