Microbial Locomotion PDF

Mediated Discussion 1 Microbial Locomotion CAS-02-502A | GROUP 4  Members Caliva, Azel Augustus Dacara, Janella R. Hizon, Joy Marie Cristy G. Moreno, Ingrid Vannah Sophia B. Pelagio, Neo Paulo C. Valdez, Kenneth Daniel Ron M.  Int...

Mediated Discussion 1 Microbial Locomotion CAS-02-502A | GROUP 4  Members Caliva, Azel Augustus Dacara, Janella R. Hizon, Joy Marie Cristy G. Moreno, Ingrid Vannah Sophia B. Pelagio, Neo Paulo C. Valdez, Kenneth Daniel Ron M.  Introduction Motility allows the cells to reach different parts of their environments. Major types of Prokaryotic Cell Movement: a) Swimming b) Gliding Swimming motility in prokaryotic cells is due to flagellum. Flagella & Swimming Motility Bacterial Flagella (15-20nm) a) Polar Flagellation The flagella are attached at one or both ends of a cell. b) Peritrichous Flagellation The flagella are attached at one or both ends of a cell.  Flagellar Structure Flagella are helical. It’s adjacent curves have a constant distance (wavelength). The flagellum also consists of the following parts: 1. Tip 2. Filament 3. Hook 4. Motor (L, P, MS, and C Rings) 5. Mot proteins 6. Fli proteins  Flagellar Movement The flagella is a tiny rotary motor, allowing the bacteria to move freely in a circular motion. It is composed of a rotor (Central Rod, L, P, MS, C Rings) and stator (Mot proteins), collectively making up the basal body and working to create torque. In addition, the Bacterial Proton Motive Force is the reason behind all of this as it is an energetic pathway responsible for bacterial flagella movement.  Archaeal Flagella Measuring only 10-13 nm in width. Several different flagellin proteins make up Archaea. Powered directly by ATP rather than by the proton motive force. Flagellar Synthesis Synthesis begins with assembly of MS and C rings in the cytoplasmic membrane, followed by the other rings, the hook, and the cap. Flagellin protein flows through the hook to form the filament and is guided into position by cap proteins.  Cell and Speed Motion The movement speed and direction of cells are influenced by the type and arrangement of their flagella. Bacteria with Polar Flagella Slow and Linear swimming pattern Bacteria with Peritrichous Flagella Erratic or tumbling swimming pattern  Mechanisms of Gliding Motility How do microorganisms glide? Gliding motility is the ability of certain- rod shaped bacteria to move on surfaces without the use of external appendages such as flagella, cilia, or pili. Slime Extrusion Mechanism: Secretion of slimy substance that Cyanobacteria moves them forward Type IV Pili Mechanism (Twitching Motility): It functions by repeated retraction and Pseudomonas extension of the pili aeruginosa Protein Adhesion Complex Mechanism: It forms a sticky adhesion at one end of the cell that Myxococcus remains attached to the surface xanthus Surface Protein Movement Mechanism (Ratcheting Mechanism): Utilizes gliding-specific proteins attached to the Flavobacterium outer membranes which propels the cell in forward motion.  What is Chemotaxis? Movement of an organism in response to a chemical stimulus. Chemotaxis in Peritrichously Chemotaxis in Polarly Flagellated Bacteria Flagellated Bacteria Flagella is present around the surface It only has a flagella on either side of of the bacteria the poles Movement of the bacteria can be runs Rotation of the flagella can be reversed (swimming forward) or tumbles (stops resulting in reversing the direction of and jiggles) the movement.  Measuring Chemotaxis Capillary Tube Assay If controlled; no change happens If attractant; microorganisms swarm the chemical If repellant; microorganisms move away from the chemical  Phototaxis True Phototaxis - Cells move up a gradient of light from lower to higher intensities. Scotophobotaxis - Occurs when a bacterium swims by chance out of the area illuminated by the microscope.  Other Taxes Aerotaxis - Movement toward or away from oxygen. Osmotaxis - Movement toward or away from concentration of ion strength. Hydrotaxis - Movement toward or away from water.  END Thank you for listening!