Investigating Impact of Mycobacterial Physiology on Mycobacteriophage Life Cycles by Mass Spectrometry

Abstract

Phage‐bacteria interaction plays an important role in both ecology and evolution. Phages lyse bacterial cells to keep nutrient and energy flows of the environment. Arm‐race between phages and bacteria drives evolution of both phages and bacteria. Current phage infection model demonstrates two typical types of phage‐bacteria interaction: lytic and lysogenic cycles. However, the model emphasizes the actions of individual phage particle and bacterial cell. Several researches have unveiled that phage‐bacteria interaction is behavior of both phage and bacterial communities, and a portion of bacterial cells can turn unsusceptible for phage infection. Since phage infection is initiated after the attachment of phage particles to bacterial cells, bacterial surface properties may impact phage‐bacteria interaction. Mycobacterium smegmatis (M. smegmatis) has a thick lipid‐rich cell envelop. Previous researches elucidated that glycopeptidolipids (GPLs) in cell envelope are involved in cell surface properties, receptors of phages and colony morphology of M. smegmatis. Therefore, GPLs may impact phage‐bacteria interaction. Besides GPLs, unique lipids including monomycoloyl trehaloses (MMTs) and triacyl glycerols (TAGs) of M. smegmatis may also impact phage‐bacteria interaction. As morphologies of both M. smegmatis cell and colony change with cell growth phase, composition of envelop lipids (GPLs, MMTs, TAGs etc.) and proteins may change with growth phage, which ultimately lead to alteration of phage‐bacteria interaction. To explore how the mycobacterial physiology affects mycobacteriophage life cycles, the impact of bacterial lipids and proteins composition change on phage and bacterial populations need to be investigated.Five mycobacteriophages from diverse clusters were selected to infect M. smegmatis cell cultures at early exponential and stationary phases for ten hours. Populations of both phages and bacterial cells were determined over time. After four and ten hours of infection, total proteins and lipids were extracted from subsamples of phage‐bacteria mixture, and further analyzed by mass spectrometry. The overall objective of this project is to figure out how phage life cycle alters when bacterial growth phase changes, and which proteins and lipids may be involved. The findings will provide a better understanding of phage‐host interactions over time and contribute towards novel applications in biotechnology.Support or Funding InformationHoward Hughes Medical Institute, Science Education Alliance; Polytechnic Institute, Purdue University; Department of Agricultural and Biological Engineering, Purdue University; Biotechnology Innovation and Regulatory Science Center, Purdue UniversityThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.