This video visualizes the intracellular movement of pathogenic Listeria monocytogenes within a mammalian host cell. It demonstrates how these bacteria propel themselves through the cytosol by recruiting and polymerizing host cell actin, forming characteristic "comet's tails." The footage captures specific behaviors such as bacteria creating temporary protrusions in the plasma membrane before bouncing back, and the division of a bacterium followed by both daughter cells immediately assembling new actin tails and beginning independent movement. The video also shows Listeria movement in cell extracts, using fluorescent labels for both the bacteria and actin, and concludes by noting that these dynamic processes can be modeled based on known biochemical and physical properties.
Summarizing Listeria monocytogenes Movement within Host Cells
0:00:03 - Intracellular Movement: Pathogenic Listeria monocytogenes are shown infecting a mammalian cell and moving within its cytosol.
0:00:10 - Actin-Based Propulsion: Bacteria recruit host cell actin, which polymerizes to form a "comet's tail," pushing the bacteria forward.
0:00:22 - Plasma Membrane Interaction: When a bacterium encounters the plasma membrane, it creates a temporary protrusion before bouncing back to continue its movement.
0:00:37 - Bacterial Division and Movement: A bacterium is observed dividing inside the host cell, and immediately after separation, both daughter cells form their own actin tails and begin moving independently.
0:00:54 - In Vitro Observation: The bacteria are also shown moving and forming actin comet tails in cell extracts, where they express green fluorescent protein (GFP) and actin is labeled with a red fluorescent dye.
0:01:09 - Dynamic Modeling: The dynamics of these actin tails and bacterial propulsion are amenable to modeling based on known biochemical and physical properties.