Ultrastructural characterization of core structures and paracrystalline inclusion bodies in L‐form cells of streptomycetes

Abstract

AbstractProtoplast type L‐form cells of Streptomyces hygroscopicus and S. griseus contain different types of inclusion bodies. Cytoplasmic cores and paracrystalline structures are peculiar inclusions which could not be observed in normal parent bacteria. The cytoplasmic cores are 1–4 μm long and 0.05–0.25 μm broad straight and stiff non‐tubular structures consisting of homogeneous moderate electron opaque material. Paracrystalline inclusions have side‐lengths between 0.2 and 0.5 μm and show a characteristic pattern of 15–20 nm thick straight dark lines and electron lucent intervening spaces of 20–30 nm. Both cytoplasmic cores and paracrystalline inclusions are apparently proteins. Their occurrence in L‐form cells indicates an altered synthesis of one or several proteins in these cell types.