How did bacterial ancestors reproduce? Lessons from L-form cells and giant lipid vesicles

摘要

In possible scenarios on the origin of life, protocellsrepresent the precursors of the rst living cells. To studysuch hypothetical protocells, giant vesicles are beingwidely used as a simple model. Lipid vesicles canundergo complex morphological changes enabling selfreproduction such as growth, ssion, and extra- andintravesicular budding. These properties of vesicular systems may in some way reect the mechanism of reproduction used by protocells. Moreover, remarkablesimilarities exist between the morphological changesobserved in giant vesicles and bacterial L-form cells,which represent bacteria that have lost their rigid cellwall, but retain the ability to reproduce. L-forms featurea dismantled cellular structure and are unable to carryout classical binary ssion. We propose that the strikingsimilarities in morphological transitions of L-forms andgiant lipid vesicles may provide insights into primitivereproductive mechanisms and contribute to a betterunderstanding of the origin and evolution of mechanismsof cell reproduction.