Cytoplasmic flows in starfish oocytes are fully determined by cortical contractions.
Cytoplasmic flows are an ubiquitous feature of biological systems, in particular in large cells, such as oocytes and eggs in early animal development. Here we show that cytoplasmic flows in starfish oocytes, which can be imaged well with transmission light microscopy, are fully determined by the cor...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2018-11-01
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| Series: | PLoS Computational Biology |
| Online Access: | https://doi.org/10.1371/journal.pcbi.1006588 |
| _version_ | 1818348826801471488 |
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| author | Nils Klughammer Johanna Bischof Nikolas D Schnellbächer Andrea Callegari Péter Lénárt Ulrich S Schwarz |
| author_facet | Nils Klughammer Johanna Bischof Nikolas D Schnellbächer Andrea Callegari Péter Lénárt Ulrich S Schwarz |
| author_sort | Nils Klughammer |
| collection | DOAJ |
| description | Cytoplasmic flows are an ubiquitous feature of biological systems, in particular in large cells, such as oocytes and eggs in early animal development. Here we show that cytoplasmic flows in starfish oocytes, which can be imaged well with transmission light microscopy, are fully determined by the cortical dynamics during surface contraction waves. We first show that the dynamics of the oocyte surface is highly symmetric around the animal-vegetal axis. We then mathematically solve the Stokes equation for flows inside a deforming sphere using the measured surface displacements as boundary conditions. Our theoretical predictions agree very well with the intracellular flows quantified by particle image velocimetry, proving that during this stage the starfish cytoplasm behaves as a simple Newtonian fluid on the micrometer scale. We calculate the pressure field inside the oocyte and find that its gradient is too small as to explain polar body extrusion, in contrast to earlier suggestions. Myosin II inhibition by blebbistatin confirms this conclusion, because it diminishes cell shape changes and hydrodynamic flow, but does not abolish polar body formation. |
| first_indexed | 2024-12-13T17:56:14Z |
| format | Article |
| id | doaj.art-2c9775629a5542da85415b1b6ac6bbeb |
| institution | Directory Open Access Journal |
| issn | 1553-734X 1553-7358 |
| language | English |
| last_indexed | 2024-12-13T17:56:14Z |
| publishDate | 2018-11-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Computational Biology |
| spelling | doaj.art-2c9775629a5542da85415b1b6ac6bbeb2022-12-21T23:36:21ZengPublic Library of Science (PLoS)PLoS Computational Biology1553-734X1553-73582018-11-011411e100658810.1371/journal.pcbi.1006588Cytoplasmic flows in starfish oocytes are fully determined by cortical contractions.Nils KlughammerJohanna BischofNikolas D SchnellbächerAndrea CallegariPéter LénártUlrich S SchwarzCytoplasmic flows are an ubiquitous feature of biological systems, in particular in large cells, such as oocytes and eggs in early animal development. Here we show that cytoplasmic flows in starfish oocytes, which can be imaged well with transmission light microscopy, are fully determined by the cortical dynamics during surface contraction waves. We first show that the dynamics of the oocyte surface is highly symmetric around the animal-vegetal axis. We then mathematically solve the Stokes equation for flows inside a deforming sphere using the measured surface displacements as boundary conditions. Our theoretical predictions agree very well with the intracellular flows quantified by particle image velocimetry, proving that during this stage the starfish cytoplasm behaves as a simple Newtonian fluid on the micrometer scale. We calculate the pressure field inside the oocyte and find that its gradient is too small as to explain polar body extrusion, in contrast to earlier suggestions. Myosin II inhibition by blebbistatin confirms this conclusion, because it diminishes cell shape changes and hydrodynamic flow, but does not abolish polar body formation.https://doi.org/10.1371/journal.pcbi.1006588 |
| spellingShingle | Nils Klughammer Johanna Bischof Nikolas D Schnellbächer Andrea Callegari Péter Lénárt Ulrich S Schwarz Cytoplasmic flows in starfish oocytes are fully determined by cortical contractions. PLoS Computational Biology |
| title | Cytoplasmic flows in starfish oocytes are fully determined by cortical contractions. |
| title_full | Cytoplasmic flows in starfish oocytes are fully determined by cortical contractions. |
| title_fullStr | Cytoplasmic flows in starfish oocytes are fully determined by cortical contractions. |
| title_full_unstemmed | Cytoplasmic flows in starfish oocytes are fully determined by cortical contractions. |
| title_short | Cytoplasmic flows in starfish oocytes are fully determined by cortical contractions. |
| title_sort | cytoplasmic flows in starfish oocytes are fully determined by cortical contractions |
| url | https://doi.org/10.1371/journal.pcbi.1006588 |
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