Growth kinetics of a bacteriophage in continuous culture

Abstract

Lytic coliphage Qbeta was grown in continuously cultured host bacteria using a cascade of stirred flow reactors. The apparatus was constructed so that the steady stream of exponentially growing bacterial cells passing through the stirred flow reactors served to prevent coevolution brought about by host-parasite interactions. Wall growth was the primary cause for deviation from ideal continuous culture conditions and is largely dependent on the surface structure of the host bacteria. Using an Escherichia coli strain deficient in adhesive type I pili expression, the desynchronization of single burst events could easily be followed over the course of four infection latency periods. Computer simulations based on a two-stage model for the Qbeta infection cycle were in perfect agreement with the experimental data. Applications of the optimized system to strategies of molecular evolution are discussed.

Control of effective expression of the phage φCTX-encoded ctx gene in Pseudomonas aeruginosa by a promoter upstream of the cos site

“…Primary ligation of the cos site of /CTX DNA was observed within 1 h (Table 2), indicating that the replication process had occurred (Xiong et al 1996). The time required for cos ligation is in accordance with experiments E. coli phages where a latent period of <1 h was observed (Ellis and DelbruÈ ck 1939;Schwienhorst et al 1996). Phage DNA ligated at the cos site by the host ligase (Chandry et al 1994) can be integrated into the chromosome and was detected between 15 and 17 h after infection with /CTX.…”

Bacteriophage Production Models: An Overview

“…Some authors have suggested the implementation of two-stage processes, one exclusively for bacteria production and a second for propagation of phages (Schwienhorst et al, 1996; Sauvageau and Cooper, 2010; Nabergoj et al, 2018a). This can be achieved with a cellstat system, where two bioreactors are connected in series with a constant flow through the system.…”

Evolution of Bacteriophage in Continuous Culture: a Model System To Test Antiviral Gene Therapies for the Emergence of Phage Escape Mutants

“…To investigate bacteriophage evolution under the selection pressure of host translational-repressor expression, we constructed a three-stage culture system ( Fig. 1) based on the previously described two-stage system (41). Briefly, the system consists of a 2.5-liter turbidostat serving as a constant supply of receptive host cells that were grown at 30°C.…”

“…In the case of normal host bacteria, bacteriophage particles are usually not diluted out under these conditions because their growth rate is much higher than that of the host cell. The system has already been used to serve different purposes: comparisons of the growth kinetics of phage with theoretical models (20,26,41), analysis of reversion kinetics starting with recombinant phage (21), production of deletion mutants by the growing of phage in a complementing host (26), and selection of RNase-resistant lytic phages (5). Furthermore, the system has been optimized to serve as a device for automated phage display experiments (41).…”