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  • 1
    Publication Date: 2010-07-27
    Description: Electrical gradients are critical for many biological processes, including the normal function of excitable tissues, left-right patterning, organogenesis and wound healing. The fundamental mechanisms that regulate the establishment and maintenance of such electrical polarities are poorly understood. Here we identify a gradient of electrical coupling across the developing ventricular myocardium using high-speed optical mapping of transmembrane potentials and calcium concentrations in the zebrafish heart. We excluded a role for differences in cellular excitability, connexin localization, tissue geometry and mechanical inputs, but in contrast we were able to demonstrate that non-canonical Wnt11 signals are required for the genesis of this myocardial electrical gradient. Although the traditional planar cell polarity pathway is not involved, we obtained evidence that Wnt11 acts to set up this gradient of electrical coupling through effects on transmembrane Ca(2+) conductance mediated by the L-type calcium channel. These data reveal a previously unrecognized role for Wnt/Ca(2+) signalling in establishing an electrical gradient in the plane of the developing cardiac epithelium through modulation of ion-channel function. The regulation of cellular coupling through such mechanisms may be a general property of non-canonical Wnt signals.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2921013/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2921013/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Panakova, Daniela -- Werdich, Andreas A -- Macrae, Calum A -- K08 HL068711/HL/NHLBI NIH HHS/ -- R21 GM075946/GM/NIGMS NIH HHS/ -- R21 GM075946-01/GM/NIGMS NIH HHS/ -- R21 GM075946-02/GM/NIGMS NIH HHS/ -- R21 GM075946-03/GM/NIGMS NIH HHS/ -- R21 GM075946-04/GM/NIGMS NIH HHS/ -- R21 HL098938/HL/NHLBI NIH HHS/ -- R21 HL098938-01/HL/NHLBI NIH HHS/ -- England -- Nature. 2010 Aug 12;466(7308):874-8. doi: 10.1038/nature09249. Epub 2010 Jul 25.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Brigham and Women's Hospital/Harvard Medical School, Cardiovascular Division, 75 Francis Street, Thorn 11, Boston, Massachusetts 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20657579" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Calcium/metabolism ; Calcium Channels, L-Type/*metabolism ; Calcium Signaling ; *Electric Conductivity ; Heart/embryology ; Ion Channel Gating/*physiology ; Myocardium/cytology/*metabolism ; Myocytes, Cardiac/metabolism ; *Signal Transduction ; Wnt Proteins/deficiency/genetics/*metabolism ; Zebrafish/*embryology/metabolism ; Zebrafish Proteins/deficiency/genetics/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2010-03-26
    Description: Recent studies indicate that mammals, including humans, maintain some capacity to renew cardiomyocytes throughout postnatal life. Yet, there is little or no significant cardiac muscle regeneration after an injury such as acute myocardial infarction. By contrast, zebrafish efficiently regenerate lost cardiac muscle, providing a model for understanding how natural heart regeneration may be blocked or enhanced. In the absence of lineage-tracing technology applicable to adult zebrafish, the cellular origins of newly regenerated cardiac muscle have remained unclear. Using new genetic fate-mapping approaches, here we identify a population of cardiomyocytes that become activated after resection of the ventricular apex and contribute prominently to cardiac muscle regeneration. Through the use of a transgenic reporter strain, we found that cardiomyocytes throughout the subepicardial ventricular layer trigger expression of the embryonic cardiogenesis gene gata4 within a week of trauma, before expression localizes to proliferating cardiomyocytes surrounding and within the injury site. Cre-recombinase-based lineage-tracing of cells expressing gata4 before evident regeneration, or of cells expressing the contractile gene cmlc2 before injury, each labelled most cardiac muscle in the ensuing regenerate. By optical voltage mapping of surface myocardium in whole ventricles, we found that electrical conduction is re-established between existing and regenerated cardiomyocytes between 2 and 4 weeks post-injury. After injury and prolonged fibroblast growth factor receptor inhibition to arrest cardiac regeneration and enable scar formation, experimental release of the signalling block led to gata4 expression and morphological improvement of the injured ventricular wall without loss of scar tissue. Our results indicate that electrically coupled cardiac muscle regenerates after resection injury, primarily through activation and expansion of cardiomyocyte populations. These findings have implications for promoting regeneration of the injured human heart.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3040215/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3040215/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kikuchi, Kazu -- Holdway, Jennifer E -- Werdich, Andreas A -- Anderson, Ryan M -- Fang, Yi -- Egnaczyk, Gregory F -- Evans, Todd -- Macrae, Calum A -- Stainier, Didier Y R -- Poss, Kenneth D -- GM075846/GM/NIGMS NIH HHS/ -- HL007101/HL/NHLBI NIH HHS/ -- HL007208/HL/NHLBI NIH HHS/ -- HL054737/HL/NHLBI NIH HHS/ -- HL064282/HL/NHLBI NIH HHS/ -- HL081674/HL/NHLBI NIH HHS/ -- K08 HL068711/HL/NHLBI NIH HHS/ -- R01 HL081674/HL/NHLBI NIH HHS/ -- R01 HL081674-05/HL/NHLBI NIH HHS/ -- R01 HL081674-06/HL/NHLBI NIH HHS/ -- R01 HL109264/HL/NHLBI NIH HHS/ -- R21 GM075946/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Mar 25;464(7288):601-5. doi: 10.1038/nature08804.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20336144" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Animals, Genetically Modified ; Cell Proliferation ; Electric Conductivity ; GATA Transcription Factors/*genetics/*metabolism ; Gene Expression Regulation ; Heart/*physiology ; Myocytes, Cardiac/*cytology/*metabolism ; Regeneration/genetics/*physiology ; Zebrafish/genetics/metabolism/*physiology ; Zebrafish Proteins/*genetics/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2014-01-13
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 4
    Publication Date: 2016-12-01
    Description: Kummerite, ideally Mn 2+ Fe 3+ Al(PO 4 ) 2 (OH) 2 ·8H 2 O, is a new secondary phosphate mineral belonging to the laueite group, from the Hagendorf-Süd pegmatite, Hagendorf, Oberpfalz, Bavaria, Germany. Kummerite occurs as sprays or rounded aggregates of very thin, typically deformed, amber yellow laths. Cleavage is good parallel to {010}. The mineral is associated closely with green Zn- and Al-bearing beraunite needles. Other associated minerals are jahnsite-(CaMnMn) and Al-bearing frondelite. The calculated density of kummerite is 2.34 g cm –3 . It is optically biaxial (–), α = 1.565(5), β = 1.600(5) and = 1.630(5), with weak dispersion. Pleochroism is weak, with amber yellow tones. Electron microprobe analyses (average of 13 grains) with H 2 O and FeO/Fe 2 O 3 calculated on structural grounds and normalized to 100%, gave Fe 2 O 3 17.2, FeO 4.8, MnO 5.4, MgO 2.2, ZnO 0.5, Al 2 O 3 9.8, P 2 O 5 27.6, H 2 O 32.5, total 100 wt.%. The empirical formula, based on 3 metal apfu is (Mn 2+ 0.37 Mg 0.27 Zn 0.03 Fe 2+ 0.33 ) 1.00 (Fe 3+ 1.06 Al 0.94 ) 2.00 PO 4 ) 1.91 (OH) 2.27 (H 2 O) 7.73 . Kummerite is triclinic, , with the unit-cell parameters of a = 5.316(1) Å, b = 10.620(3) Å , c = 7.118(1) Å, α = 107.33(3)°, β = 111.22(3)°, = 72.22(2)° and V = 348.4(2) Å 3 . The strongest lines in the powder X-ray diffraction pattern are [ d obs in Å(I) ( hkl )] 9.885 (100) (010); 6.476 (20) (001); 4.942 (30) (020); 3.988 (9) ( ); 3.116 (18) ( ); 2.873 (11) ( ). Kummerite is isostructural with laueite, but differs in having Al and Fe 3+ ordered into alternate octahedral sites in the 7.1 Å trans -connected octahedral chains.
    Print ISSN: 0026-461X
    Electronic ISSN: 1471-8022
    Topics: Geosciences
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  • 5
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