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T4 Infection of Stationary Phase E. coli |
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Elizabeth Kutter, Thain Maurer, Alexey Ball, Tor Nelson, Celia Beamish, Elizabeth Thomas, Erik Goldberg, Lynn Messinger, Pia Lippincott and Jim Neitzel, Evergreen State College, Olympia, WA Bacteriophage have traditionally been studied under lab conditions with hosts in exponential phase. To explore infection in an environment closer to nature, we are investigating the infection of stationary phase E. coli by T4. We find that T4 infection of E. coli B or W3110 from 1 to 4 days after innoculation in M9 with glucose leads to an apparently dormant hibernation phase which can last at least several days. If the infected cells are then plated for ³infective centers² or glucose and amino acids are added after a 1:3 dilution in M9 salts, the T4 infection cycle resumes, but with important variations. The extent and timing of subsequent phage production reflects the time in stationary phase. Pulse labeling and SDS-PAGE gel electrophoresis were used to compare the time course of protein synthesis after addition of glucose in infected and uninfected E. coli. The results were in sharp contrast to those seen in exponential phase, where host protein synthesis is shut off rapidly. After the transition into lag phase, infected cells made most host proteins, while showing induction of specific bacteriophage proteins; by 2 hours, most proteins were phage specific. These results may help explain the coexistence of lytic phage and host in nature and may have important implications in the microbial ecologies of areas as diverse as industry, the environment, and the human gut. Back to Current Projects. E. coli Membrane Changes During Bacteriophage T4 Infection Previous research on phospholipids in E. coli during T4 bacteriophage infection found changes in total phospholipid synthesis. We sought to determine if and how the fatty acid composition of bacterial membranes changed. After extraction of lipids and preparation of methyl esters, we used a Hewlett-Packard GC/MS to determine the composition of fatty acids both while the bacteria were growing in broth culture and during T4 infection. We found that significant short-lived changes in fatty acid composition occur immediately after T4 infection. This composition resembles that of fatty acids found in stationary phase cells. |
Bacteriophage |
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Last Updated: May 29, 2008 All content and images on this site are copyrighted by The Evergreen State College. |
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