Mechanism for the Regulation of Cell Division inAgmenellum

Abstract

We describe a nonlethal temperature-conditional mutant of Agmenellum quadruplicatum which allows dissociation of the processes of growth and cell division. With this system, evidence has been obtained for the regulation of one step in the process of cell division by a small effector molecule. The effector molecule is apparently released into the surrounding medium and can be obtained from lyophilized spent medium by extraction with 80% ethanol. The addition of this extract to serpentine filaments of the SN29 mutant strain stimulates cell division in these filaments and leads to the production of cells approximating normal dimensions within one generation time. The degree of stimulation of cell division is directly related to the amount of extract added. A general hypothesis is presented for the positive regulation of the initiation of cell wall and cell membrane invagination in this organism.

Antibiotics of the virginiamycin family, inhibitors which contain synergistic components.

“…More recent work has shown that elongation of Bdellovibrio is a polar and unidirectional process, and that division into daughter cells requires an unimpaired protein synthesis, as well as the accumulation of a low-molecular-weight division protein (101). The latter is apparently released by dividing cells and is similar to the division proteins found by several investigators in different bacterial species (149,150,271,351).…”

Control of cell division in bacteria.

“…In certain permeability mutants, substances comprising "division potential" may be lost by leakage through membranes. An example of this may be filament-forming mutants of the blue-green alga Agmenellum quadruplicatum which leak a division-related effector (61,62). Erwinia sp.…”

Peptidoglycan synthesis and turnover in cell division mutants of Agmenellum

“…Strain I Agricultural Experiment Station Publication number 6151. SN-29 is a low-temperature, conditional filamentous mutant which has been described in several earlier investigations (13,15). Strain S-4 is a septate mutant (16) impaired in cell separation.…”