DETERMINATION OF THE THICKNESS OF THE BOUNDARY-LAYER SURROUNDING BACTERIAL PHA INCLUSION-BODIES, AND IMPLICATIONS FOR MODELS DESCRIBING THEMOLECULAR ARCHITECTURE OF THIS LAYER

The thickness of the boundary layer surrounding polyhydroxyalkanoic ac id (PHA) inclusion bodies in bacteria Ras determined from electron mic rographs of ultrathin cell sections. The obtained values were compared with the thickness of boundary layers of other kinds of prokaryotic i nclusion bodies known to be monolayers (sulfur globule, hydrocarbon-co ntaining inclusion: carboxysome, gas vesicle, chlorobium vesicle) and the thickness of typical bilayer membranes (cytoplasmic membrane, phot osynthetic vesicle). The data are discussed in view of contradicting m odels published recently for the molecular architecture of the boundar y layer of PHA inclusion bodies.