Investigation of the final stages of a P4-like coliphage infection in Escherichia coli through scanning, transmission and nano-scanning-auger electron microscopy (NanoSAM)

Abstract

Enlargement of bacterial cells during bacteriophage replication has been observed in the past with T-even, Lambda and N4 bacteriophages by the use of transmission electron microscopy (TEM) and light microscopy techniques and hypotheses explaining the enlargement of bacteriophage-infected cells have been postulated in literature. In this study, enlarged Escherichia coli cells were observed using scanning electron microscopy (SEM) after 45 min of a P4-like bacteriophage infection. These bacteria were also studied using scanning auger microscopy (SAM) in combination with anthe Argon-ion gunof a scanning Auger microscope (SAM) by which the bacteria were etched. Neither SEM nor SAM have been used during the analysis of bacteriophage infected enlarged host cells, making this study unique. The use of SAM on bacteriophage-related investigations is also novel. Small phage-like particles were observed inside the etched enlarged and etched normal bacteriophage-exposed host cells. The presence of bacteriophage-like particles inside both types of cells confirmed that the enlarged cells, which were scarce in this sample, were not artifacts of some kind such as contamination by other microorganisms. Due to the scarcity of these enlarged cells, it was concluded that a previous hypothesis on tThe enlargement of bacteriophage infected host cells coincides with previous studies reported in literature, did not apply to thebut never before with P4-like bacteriophages. used in this study. Key words: Bacteriophage, coliphage, replication cycle, Esherichia coli, Nano scanning electron microscopy.