Before revision:  Noteworthy, a structural transition in the network is observed such that, for connectivities k\ge40 , bacterial PPI networks are mostly populated by genesthat are conserved, essential and which , in most cases, belong to the COG cluster J, related to ribosomal functions and to the processing of genetic information.
After revision:  In particular, we isolate a core of highly connected proteins (with connectivities k\ge40 , bacterial PPI networks are mostly populated by genesthat are conserved, essential and which , in most cases, belong to the COG cluster J, related to ribosomal functions and to the processing of genetic information.