Many animal embryos pull and close an epithelial sheet around the ellipsoidal egg surface during a gastrulation process known as epiboly. The ovoidal geometry dictates that the epithelial sheet first expands and subsequently compacts. Moreover, the spreading epithelium is mechanically stressed and this stress needs to be released. Here we show that during extraembryonic tissue (serosa) epiboly in the insect Tribolium castaneum, the non-proliferative serosa becomes regionalized into a solid-like dorsal region with larger non-rearranging cells, and a more fluid-like ventral region surrounding the leading edge with smaller cells undergoing intercalations. Our results suggest that a heterogeneous actomyosin cable contributes to the fluidization of the leading edge by driving sequential eviction and intercalation of individual cells away from the serosa margin. Since this developmental solution utilized during epiboly resembles the mechanism of wound healing, we propose actomyosin cable-driven local tissue fluidization as a conserved morphogenetic module for closure of epithelial gaps.

• MeSH
• aktomyosin metabolismus   MeSH
• biomechanika MeSH
• epitel embryologie   metabolismus   MeSH
• gastrulace fyziologie   MeSH
• hmyz embryologie   MeSH
• hmyzí proteiny metabolismus   MeSH
• hojení ran MeSH
• morfogeneze MeSH
• pohyb buněk MeSH
• serózní membrána embryologie   metabolismus   MeSH
• Tribolium embryologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Early male-killing (MK) bacteria are vertically transmitted reproductive parasites which kill male offspring that inherit them. Whereas their incidence is well documented, characteristics allowing originally non-MK bacteria to gradually evolve MK ability remain unclear. We show that horizontal transmission is a mechanism enabling vertically transmitted bacteria to evolve fully efficient MK under a wide range of host and parasite characteristics, especially when the efficacy of vertical transmission is high. We also show that an almost 100% vertically transmitted and 100% effective male-killer may evolve from a purely horizontally transmitted non-MK ancestor, and that a 100% efficient male-killer can form a stable coexistence only with a non-MK bacterial strain. Our findings are in line with the empirical evidence on current MK bacteria, explain their high efficacy in killing infected male embryos and their variability within and across insect taxa, and suggest that they may have evolved independently in phylogenetically distinct species.

• MeSH
• Bacteria klasifikace   genetika   MeSH
• biologická evoluce * MeSH
• fyziologie bakterií MeSH
• hmyz embryologie   mikrobiologie   MeSH
• interakce hostitele a patogenu * MeSH
• poměr pohlaví MeSH
• přenos infekční nemoci * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• biologická evoluce MeSH
• biologická proměna MeSH
• embryo nesavčí MeSH
• finanční podpora výzkumu jako téma MeSH
• fylogeneze MeSH
• hmyz embryologie   klasifikace   ultrastruktura   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

• MeSH
• hmyz embryologie   růst a vývoj   MeSH
• spermie fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

• MeSH
• hmyz anatomie a histologie   embryologie   MeSH
• Publikační typ
• periodika MeSH

• Konspekt
• Biologické vědy
• NLK Obory
• biologie