Cores, Microbial Organelles Possibly Specific to Group D Streptococci

Abstract

A long, thin, approximately cylindrical core spans the interior of cells of 24-hr cultures of all group D streptococci that were examined, five strains of Streptococcus faecalis, single strains of S. faecalis subsp. zymogenes and S. durans, and three strains of Streptococcus spp. In one strain of S. faecalis, serial section electron microscopy showed that most cells possess a core. The core is 0.10 to 0.16 Asm thick and consists of a matrix and an axial array of ribosomelike particles. It resembles one of two types of cores present in a stable protoplast form of one of the S. faecalis strains. Cores were not present in single strains of S. pyogenes (f-hemolytic group A), S. agalactiae (group B), S. dysgalactiae (group C), S. equisimilis (group C), and S. mitis (viridans group) that were examined; nor were cores observed in single strains of Staphylococcus aureus, Escherichia coli, and Bacillus megaterium. Cores may be useful, therefore, in identification of group D streptococci. For preservation and rapid recognition of cores, a glutaraldehyde-osmium tetroxide sequence of fixation appears superior to the osmium tetroxide method often employed in processing bacteria for electron microscopy.

The biology of methanogenic bacteria.

“…Coccus-type cells. The fine structure of M. ruminantium is very similar to that reported for streptococci (39,63). The cell envelope of M. ruminantium has a distinctive triple-layered appearance (Fig.…”

Early Changes in the Ultrastructure of Streptococcus faecalis After Amino Acid Starvation

“…Proc., p. 38, 1969) of many members of the group D streptococci, including the ATCC 9790 strain used in these studies. In fact, it has been proposed that these organelles are specific to group D streptococci (14). In several thousand sections, of several dozen cell preparations from both LOG-and stationary-phase cells, we have failed to observe a single core, or core-like structure.…”

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

“…Because the fine structure of the non-membraneous cores is very siniilar to those of gram positive cell walls somc authors suggest that they may be deposits of cell wall material containing the group D antigene formed as a consequence of a disturbed wall synthesis (COIIEN et al , MCCANDLESS et al 1968 It was shown by COLEMAN and BLEIWEIS (1971,1977) that the typical cores in D streptococci are proteins containing no cell wall components. They are stable a t p H 6; and their forniation can be inhibited by chloramphenicol.…”