Regulation of phage λ development with the growth rate of host cells: A homeostatic mechanism

Cleavage of the cII protein of phage lambda by purified HflA protease: control of the switch between lysis and lysogeny.

“…Incubation was for 15 bypassed by an hflA -mutation (38). Carbon-source starvation markedly raises the frequency of lysogenization (39) [although exponential growth in poor carbon sources does not (40) (43) and turns on SOS mutagenesis the overproduced through cleavage of UmuD (44)(45)(46). We expect that other assays, cII would examples of this mode of regulation will be important for state (33) …”

A New Look at Bacteriophage λ Genetic Networks

“…High multiplicities of infection ensure that CII accumulates to a threshold allowing the lysogenic switch. This CII multiplicity-dependent switch is epistatic to the N effect in rich or minimal medium (18). On the other hand, infection of a cell by a single phage leads predominantly to lytic development under all growth conditions.…”

Inhibition of spontaneous induction of lambdoid prophages in Escherichia colicultures: simple procedures with possible biotechnological applications

“…These differences could be caused either by a lower frequency of prophage induction in slowly growing cells or by a less efficient lytic development after excision of the phage DNA from the host chromosome under conditions supporting low bacterial growth rates. In fact, low burst sizes of λ phage in slowly growing bacteria have already been reported [7,8,9]. Nevertheless, irrespective of the specific mechanism of the observed phenomenon, it is clear that the number of phages per cell in cultures of slowly growing lysogenic bacteria was below the detection limit (Table 1).…”

“…It was found previously that bacterial growth rate significantly influences lytic development of bacteriophages T4 and λ [6,7,8,9]. We asked whether the efficiency of spontaneous λ prophage induction is also dependent on this parameter.…”

“…Although effects of bacterial growth rate on phage lytic development have been investigated previously [7,8,9], the results of these studies were used in basic research rather than in biotechnological applications. Here we report that deleterious effects of spontaneous lambdoid prophage induction are significantly decreased at low growth rates of lysogenic bacteria relative to high growth rates.…”