to that of the cells suffices to explain our observations and yields a morphospace consistent with observations across a range of multicellular choanoflagellate colonies. Overall, our biophysical perspective on rosette development complements previous genetic perspectives and, thus, helps illuminate the interplay between cell biology and physics in regulating morphogenesis.

Laugié, M., Donnadieu, Y., Ladant, J.-B., Green, M., Bopp, L., Raisson, F., 2020. Stripping back the Modern to reveal Cretaceous climate and temperature gradient underneath. Climate of the Past Discussions 2020, 1-39.

https://www.clim-past-discuss.net/cp-2019-166/ During past geological times, the Earth suffered several intervals of global warmth but their driving factors remain equivocal. A careful appraisal of the main processes involved in those past events is essential to evaluate how they can inform future climates, and thus to provide decision makers with a clear understanding of the processes at play in a warmer world. In this context, the greenhouse Earth of the Cretaceous era, specifically the Cenomanian- Turonian (~ 94 Ma), is of particular interest, as it c orresponds to a thermal maximum. Here we use the IPSL-CM5A2 Earth System Model to unravel the forcing parameters of the Cenomanian-Turonian greenhouse climate. We perform six simulations with an incremental change in five major boundary conditions in order to isolate their respective role on climate change between the Cretaceous and the preindustrial. Starting with a preindustrial simulation, we implement: (1) the absence of polar ice sheets, (2) the increase in p atmospheric CO to 1120 ppm, (3) the change of vegetation and soil parameters, (4) the 1 %decrease in the 2 Cenomanian-Turonian value of the solar constant and (5) the Cenomanian-Turonian paleogeography. Between the first (preindustrial) simulation and the last (Cretaceous) simulation, the model simulates a global warming of p more than 11 °C. Most of this warming is driven by the increase in atmospheric CO to 1120 ppm. 2 Paleogeographic changes represent the second major contributor to the global warming while the reduction in the solar constant counteracts most of the geographically-driven global warming. We also demonstrate that the implementation of Cretaceous boundary conditions flattens the temperature gradients compared to the piControl simulation. Interestingly, we show that paleogeography is the major driver of the flattening in the low- to mid- p latitudes whereas the CO rise and polar ice sheet retreat dominate the high-latitudes response. 2

Le, T., Žárský, V., Nývltová, E., Rada, P., Harant, K., Vancová, M., Verner, Z., Hrdý, I., Tachezy, J., 2020. Mastigamoeba balamuthi Anaerobic peroxisomes in . Proceedings of the National Academy of Sciences 117, 2065-2075.

https://doi.org/10.1073/pnas.1909755117 Significance: It is generally accepted that peroxisomes are absent in anaerobic eukaryotes. These organelles have evolved to compartmentalize oxidative pathways and prevent cellular oxidative damage, namely, the β - oxidation of fatty acids that utilizes molecular oxygen and produces hydrogen peroxide. Mitochondria possess a parallel β -oxidation pathway coupled with the respiratory chain. The adaptation of eukaryotes to anaerobiosis is reflected by the reduction of mitochondrial metabolism and, not surprisingly, concomitant loss of peroxisomes. Mastigamoeba balamuthi The free-living anaerobic protist is an organism that contradicts this paradigm. Mastigamoeba Although possesses hydrogenosomes, an anaerobic form of mitochondria, it also harbors peroxisomes. These organelles contain the archetypical Pexs that are required for peroxisomal biogenesis; however, they lack the hallmarks of peroxisomal metabolism, β -oxidation and catalase. Abstract: The adaptation of eukaryotic cells to anaerobic conditions is reflected by substantial changes to mitochondrial metabolism and functional reduction. Hydrogenosomes belong among the most modified mitochondrial derivative and generate molecular hydrogen concomitant with ATP synthesis. The reduction of mitochondria is frequently associated with loss of peroxisomes, which compartmentalize pathways that generate reactive oxygen species (ROS) and thus protect against cellular damage. The biogenesis and function of peroxisomes are tightly coupled with mitochondria. These organelles share fission machinery components, oxidative metabolism pathways, ROS scavenging activities, and some metabolites. The loss of peroxisomes in eukaryotes with reduced mitochondria is thus not unexpected. Surprisingly, we identified peroxisomes in the Mastigamoeba balamuthi anaerobic, hydrogenosome-bearing protist . We found a conserved set of peroxin (Pex) proteins that are required for protein import, peroxisomal growth, and division. Key membrane-associated