Are gram-positive bacteria capable of electron transfer across their cell wall without an externally available electron shuttle

The extensive contributions by Terry Beveridge to our understanding of the differences in cell wall organization with respect to structure, chemistry and compartmentalization between gram-positive and gram-negative bacteria are summarized. These contributions greatly aided in conceptualization of recent discoveries concerning electron export and import across cell walls of some gram-negative bacteria. Although electron export and import across the cell wall by any gram-positive has not been documented so far, Beveridge's observations and concepts concerning cell walls of gram-positive bacteria suggest potential mechanisms by which such electron transfer may occur.