On the reproductive mechanism of Gram-negative protocells

Protocells are thought to have existed on early Earth before the origin of prokaryotes. These primitive cells are believed to have carried out processes like replication solely based on the physicochemical properties of their cell constituents. Despite considerable efforts, replication of a living cell-driven entirely by laws of physics and chemistry has never been achieved. To test this hypothesis, we transformed extant bacteria into sacks of cytoplasm, incapable of regulating either their morphology or reproductive processes. We then exposed these proxy-protocells (bacterial protoplasts) to presumed Archaean Eon environmental conditions to understand if or how these cells reproduce. Contrary to the current presumption that bacterial protoplasts reproduce in a haphazard manner, under our experimental conditions they reproduced via a multi-stage reproductive cycle, resulting in viable daughter cells. Our observations suggest that this mechanism of reproduction could in fact be well explained from a biophysical perspective. Based on our observations we argue that this method of reproduction is better suited for the environmental conditions of early Earth. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=166 SRC="FIGDIR/small/470037v1_ufig1.gif" ALT="Figure 1"> View larger version (56K): org.highwire.dtl.DTLVardef@16a35aorg.highwire.dtl.DTLVardef@3ea126org.highwire.dtl.DTLVardef@1c5e7c4org.highwire.dtl.DTLVardef@1f30421_HPS_FORMAT_FIGEXP M_FIG C_FIG