6β-Amidinopenicillanic Acids—a New Group of Antibiotics

Analysis of the effect of ppGpp on the ftsQAZ operon in Escherichia coli

“…When added to a wild-type E. coli culture, the cells become spherical (Lund and Tybring, 1972), and, although the optical density increases for many generations, cell division stops rather quickly, at least in rich medium (Vinella et al, 1993). The loss of rod shape in the presence of mecillinam implies that PBP2 is required for lateral elongation of the peptidoglycan cell wall (Spratt, 1975).…”

Distinct penicillin binding proteins involved in the division, elongation, and shape of Escherichia coli K12.

“…The Fig. 1, and 3) should be to produce a normal rod-shaped filament during the first 50 min. After 50 min the blocking of protein 2 should result in the production of the cell shape changes (bulges) within these filaments.…”

“…In addition, some of these compounds produce bulges in cells at intermediate concentrations (2). Another penicillin derivative (the amidino-penicillanic acid, mecillinam-previously called FL1060) produces ovoid-shaped cells at low concentrations without specifically inhibiting cell division or causing typical penicillin lysis (3)(4)(5).…”

Triggering of autolytic cell wall degradation in Escherichia coli by beta-lactam antibiotics

“…Others, such as cephalexin, cause inhibition of cell division and induce the formation of long filamentous cells (11,29). Still another group of beta-lactams, namely, mecillinam (10,21) and, at low concentrations, thienamycin and clavulanic acid (31), cause the formation of ovoid cells. In parallel to their different physiological effects, beta-lactams also seem to differ in their affinities to the penicillin-binding proteins (PBPs) of the E. coli plasma membrane (28), and beta-lactams which show strong cell lytic action have high affinity for PBP-1 (-PBPla and/or -lb) (30,33).…”