23. Van Baalen, C. and R. M. Brown, Jr.
1969. The ultrastructure of the marine blue-green alga Trichodesmium
erythraeum, with special reference to the cell wall, gas vacuoles,
and cylindrical bodies. Archiv. f. Mikrobiol. 69:79-91.
23. Summary
The marine blue green alga, Trichodesmium
erythraeum, was studied with electron microscopy in an attempt
to elucidate the structural basis for its rapid lysis when removed
from its marine environment. In this connection, it was found
that a thinning of the electron-dense layer of the longitudinal
wall at the site adjacent to transverse wall attachment was responsible
for lysis. The underlying biochemical basis for this change has
not been elucidated because of the extreme difficulties of maintaining
and growing the alga in culture under defined conditions. Several
other features of considerable interest also were found. Especially
interesting is the very regular array of gas vacuoles in the form
of a hollow cylinder which shields most of the photosynthetic
system. It was suggested that the gas vacuoles might possibly
function optically, having adaptive value in protecting the free-floating
alga from excessive radiation. In addition, a detailed structure
of the cylindrical bodies was presented, and its structure with
the photosynthetic lamellae was compared. On the basis of sectoring
to form fragments of double lamellar units from the cylindrical
body which are identical in structure to the photosynthetic lamellae,
it has been postulated that the cylindrical body may be the site
of synthesis for the photosynthetic system in Trichodesmium
erythraeum.