Osmotic gradients induce stable dome morphogenesis on extracellular matrix

ABSTRACTOne of the fundamental processes in morphogenesis is dome formation, but many of the mechanisms involved are unexplored. Previous in vitro studies showed that an osmotic gradient is the driving factor of dome formation. However, these investigations were performed without extracellular matrix (ECM), which provides structural support to morphogenesis. With the use of ECM, we observed that basal hypertonic stress induced stable domes in vitro that have not been seen in previous studies. These domes developed as a result of ECM swelling via aquaporin water transport activity. Based on computer simulation, uneven swelling, with a positive feedback between cell stretching and enhanced water transport, was a cause of dome formation. These results indicate that osmotic gradients induce dome morphogenesis via both enhanced water transport activity and subsequent ECM swelling.

Chromatin streaming from giant polyploid nuclei in Ishikawa endometrial hollow spheroids results in the amitotic proliferation of nuclei that fill the spheroid envelope

This paper describes the amitotic proliferation of nuclei that fill the envelope of Ishikawa hollow spheroids. The presence of hollow spheroids in malignant ascites fluid has intrigued cancer researchers, but little is understood about how they form. Observations in Ishikawa endometrial cell cultures demonstrate that nuclei filling the spheroid envelope are generated amitotically by the same mechanism responsible for cell formation in domes. Transient structures of aggregated chromatin surrounded by fused giant mitochondria, the initiating structure for dome formation, are also the starting point for the differentiation of unicellular polyploid hollow spheroids. Nuclei from monolayer cells are aggregated in a single enlarged cell where they become surrounding by giant fused mitochondria. A gaseous vacuole forms inside the mitonucleon extending it so that all of the cell material, including nuclei is pressed against the cell membrane. The resulting unicellular hollow spheroid detaches from the colony, capable of migration from the site of its formation. Ultimately, pressure on the aggregated chromatin results in the release of streams of chromatin granules that initially travel as if guided by microtubules through the shell of the hollow spheroid. Granules dissolve into filaments and, as initially described in dome formation, this material self-assembles into clusters of nuclei. Nuclei move out of these clusters into a regular array within the spheroid envelope, with formation of cell membranes as the final step in the creation of multicellular hollow spheroids. The curved membrane characteristic of domes and spheroids, as well as colonies of nuclei produced by amitosis have been identified in tumor tissue that survives chemotherapy, suggesting that amitotic cell proliferation may at least partially explain the population of cancer tumor cells in humans that are resistant to chemotherapy.

Chromatin streaming from giant polyploid nuclei in Ishikawa endometrial hollow spheroids results in the amitotic proliferation of nuclei that fill the spheroid envelope

This paper describes the amitotic proliferation of nuclei that fill the envelope of Ishikawa hollow spheroids. The presence of hollow spheroids in malignant ascites fluid has intrigued cancer researchers, but little is understood about how they form. Observations in Ishikawa endometrial cell cultures demonstrate that nuclei filling the spheroid envelope are generated amitotically by the same mechanism responsible for cell formation in domes. Transient structures of aggregated chromatin surrounded by fused giant mitochondria, the initiating structure for dome formation, are also the starting point for the differentiation of unicellular polyploid hollow spheroids. Nuclei from monolayer cells are aggregated in a single enlarged cell where they become surrounding by giant fused mitochondria. A gaseous vacuole forms inside the mitonucleon extending it so that all of the cell material, including nuclei is pressed against the cell membrane. The resulting unicellular hollow spheroid detaches from the colony, capable of migration from the site of its formation. Ultimately, pressure on the aggregated chromatin results in the release of streams of chromatin granules that initially travel as if guided by microtubules through the shell of the hollow spheroid. Granules dissolve into filaments and, as initially described in dome formation, this material self-assembles into clusters of nuclei. Nuclei move out of these clusters into a regular array within the spheroid envelope, with formation of cell membranes as the final step in the creation of multicellular hollow spheroids. The curved membrane characteristic of domes and spheroids, as well as colonies of nuclei produced by amitosis have been identified in tumor tissue that survives chemotherapy, suggesting that amitotic cell proliferation may at least partially explain the population of cancer tumor cells in humans that are resistant to chemotherapy.

Japanese volcanoes visualized with muography

High-energy muons that are generated via the reaction between primary cosmic rays and the Earth's atmosphere can be used to map out the density distribution in shallow parts of a volcano's interior. This new subterranean imaging technique called muography has been applied to three different kinds of volcano dynamics in Japan: lava dome formation, vulcanian explosions and magma convection. Taking all of the observational data together, it appears that muography can serve as a new and alternative volcano observation technique, providing a fresh approach to understanding eruption mechanism. This review describes observational studies in which muography has been used to explore the volcano's interior. This article is part of the Theo Murphy meeting issue ‘Cosmic-ray muography’.