One or two membranes? Diderm Firmicutes challenge the Gram‐positive/Gram‐negative divide

@article{Megrian2020OneOT,
  title={One or two membranes? Diderm Firmicutes challenge the Gram‐positive/Gram‐negative divide},
  author={Daniela Megrian and Najwa Taib and Jerzy Witwinowski and Christophe Beloin and Simonetta Gribaldo},
  journal={Molecular Microbiology},
  year={2020},
  volume={113},
  pages={659 - 671}
}
How, when and why the transition between cell envelopes with one membrane (Gram‐positives or monoderms) and two (Gram‐negative or diderms) occurred in Bacteria is a key unanswered question in evolutionary biology. Different hypotheses have been put forward, suggesting that either the monoderm or the diderm phenotype is ancestral. The existence of diderm members in the classically monoderm Firmicutes challenges the Gram‐positive/Gram‐negative divide and provides a great opportunity to tackle the… 
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TLDR
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