Damien Devos (EMBL, Heidelberg Germany, moving to the Center of Organismal Studies (COS) at the Heidelberg University) then presented his talk entitled "Microbiology's platypus". He first recapitulated the origin of the protocoatomer hypothesis, starting from a structural analysis of the nuclear pore complex; again highlighting the limits of sequences-only based methods. The first part of his talk ended with the importance of the membrane coat innovation as they form the core of the multi-protein complexes sustaining most divisions of the eukaryotic endomembrane system. As such, they must have been present in the LECA (him again) and probably in the ancestor of.
He then developed a method to use structure (since sequence search is limited, remember?) to search for this particular protein architecture and found it only in some of the PVC proteomes. Immunological characterization located such bacterial membrane coat-like proteins in the paryphoplasm of Gemmata cells. However, the differences of interpretation between him and the previous speaker, John Fuerst, became clear at that moment. Damien doesn't interpret the planctomycetes cell plan as different from the classical bacterial one, but just as an extension of it, when John interprets it as fundamentally different. An interesting discussion ensued and was followed over tee. Damien then presented his last work, where they reconstructed in three-dimensions various complete Gemmata cells. He showed a movie that first went through the tomogram of a cell, followed by the process of modeling the membranes and other features and ending with the final model. Unlike the previous speaker, no isolated compartments or even nucleoid envelope could be observed in this study. It would be interesting to pursue this analysis and resolve this issue. Damien then ended with his interpretation of the possible evolutionary connections between the PVC and the eukaryotic or archaeal features. He made the parallel between the special features found in PVC and the eukaryotes or archaea and the avian or reptilian ones found in the mammal platypus, hence the title of his talk.
He then developed a method to use structure (since sequence search is limited, remember?) to search for this particular protein architecture and found it only in some of the PVC proteomes. Immunological characterization located such bacterial membrane coat-like proteins in the paryphoplasm of Gemmata cells. However, the differences of interpretation between him and the previous speaker, John Fuerst, became clear at that moment. Damien doesn't interpret the planctomycetes cell plan as different from the classical bacterial one, but just as an extension of it, when John interprets it as fundamentally different. An interesting discussion ensued and was followed over tee. Damien then presented his last work, where they reconstructed in three-dimensions various complete Gemmata cells. He showed a movie that first went through the tomogram of a cell, followed by the process of modeling the membranes and other features and ending with the final model. Unlike the previous speaker, no isolated compartments or even nucleoid envelope could be observed in this study. It would be interesting to pursue this analysis and resolve this issue. Damien then ended with his interpretation of the possible evolutionary connections between the PVC and the eukaryotic or archaeal features. He made the parallel between the special features found in PVC and the eukaryotes or archaea and the avian or reptilian ones found in the mammal platypus, hence the title of his talk.
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