Streptococcus pyogenes and Streptococcal Disease (page 4)
(This chapter has 4 pages)
© Kenneth Todar, PhD
Gallery of electron micrographs of Streptococcus pyogenes
from The Laboratory
of Pathogenesis and Immunology at Rockefeller University, the home
of research on Streptococcus pyogenes
Critical point dried whole
group
A streptococci (Streptococcus pyogenes) viewed directly by
transmission
electron microscopy (TEM 6,500X). Chains of streptococci are clearly
evident.
To remove cell surface proteins, cells were treated with trypsin prior
to preparation and mounting. Strain: D471; M-type 6. Electron
micrograph
of Streptococcus pyogenes by Maria Fazio and Vincent A.
Fischetti,
Ph.D. with permission. The
Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller
University.
Dividing streptococci
(12,000X).
Electron micrograph of Streptococcus pyogenes by Maria Fazio
and
Vincent A. Fischetti, Ph.D. with permission. The
Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller
University.
Electron micrograph of an
ultra-thin
section of a chain of group A streptococci (20,000X). The cell surface
fibrils, consisting primarily of M protein, are clearly evident. The
bacterial
cell wall, to which the fibrils are attached, is also clearly seen as
the
light staining region between the fibrils and the dark staining cell
interior.
Incipient cell division is also indicated by the nascent septum
formation
(seen as an indentation of the cell wall) near the cell equator. The
streptococcal
cell diameter is equal to approximately one micron. Electron micrograph
of Streptococcus pyogenes by Maria Fazio and Vincent A.
Fischetti,
Ph.D. with permission. The
Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller
University.
Negative staining of group A
streptococci viewed by TEM 28,000X. The "halo" around the chain of
cells
(approximately equal in thickness to the cell diameter) is the remnants
of the capsule that may be found surrounding the exterior of certain
strains
of group A streptococci. The septa between pairs of dividing cells may
also be seen. Electron micrograph of Streptococcus pyogenes by
Maria
Fazio and Vincent A. Fischetti, Ph.D. with permission. The
Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller
University.
High magnification electron
micrograph of an ultra-thin section of a group A streptococcus sibling
pair (70,000 X). At this magnification, especially in the cell on the
left,
the cell wall and cell surface fibrils, consisting primarily of M
protein,
are well defined. Interdigitaion of these fibrils between neighboring
cells
of different chains is also in plain view. Strain: C126/21/1; M-type
43.
Electron micrograph of Streptococcus pyogenes by Maria Fazio
and
Vincent A. Fischetti, Ph.D. with permission. The
Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller
University.
