Provided by magdalene so, phd, University of Washington 5.0kV17.1mmx8.00kSE(M)3/52010 5.00um Bacteria caught in the act of infecting a human cell A cluster of Neisseria gonorrhoeae attached to a human epithelial cell. Bacteria are pseudocolored in yellow. All other features are in grey. The bacteria are covered by a network of fibers called Type lv pili. These Type Iv pili extend from, and retract into, the body of the bacterium, much like a fishing line. when the fibers retract, they pull with tremendous force on the surface of a human cell, causing changes to the cell surface Fiber retraction stimulates the formation of microvilli, seen here as thick tubes underneath and adjacent to the bacteria. It also causes the membrane to form waves". These and other changes to the human cell caused by Type iv pili are the beginning of the infection process. 2016/5/12 E. coli-Junqi's Lecture 152016/5/12 E.coli-Junqi's Lecture 15 Bacteria caught in the act of infecting a human cell A cluster of Neisseria gonorrhoeae attached to a human epithelial cell. Bacteria are pseudocolored in yellow. All other features are in grey. The bacteria are covered by a network of fibers called Type IV pili. These Type IV pili extend from, and retract into, the body of the bacterium, much like a fishing line. When the fibers retract, they pull with tremendous force on the surface of a human cell, causing changes to the cell surface. Fiber retraction stimulates the formation of microvilli, seen here as thick tubes underneath and adjacent to the bacteria. It also causes the membrane to form “waves”. These and other changes to the human cell caused by Type IV pili are the beginning of the infection process. Provided by Magdalene So, PhD, University of Washington