MBIO 1010 Lecture Notes - Lecture 10: Pilus, Bacterial Gliding, Ionic Strength

• School: University of Manitoba
• Department: Microbiology
• Course: MBIO 1010
• Professor: Christopher Rathgeber

Document Summary

Differences in swimming motions (figure 2. 54: peritrichously flagellated cells move slowly in a straight line, polarly flagellated cells move more rapidly and typically spin around. Unidirectional flagella - doesn"t ha(cid:448)e a(cid:271)ilit(cid:455) (cid:449)ith ccw dire(cid:272)tio(cid:374) so it has to stop. Mechanisms: excretion of polysaccharide slime, type iv pili, gliding-specific proteins. Taxis: directed movement in response to chemical or physical gradients o chemotaxis: response to chemicals: phototaxis: response to light, aerotaxis: response to oxygen, osmotaxis: response to ionic strength, hydrotaxis: response to water. If it"s e(cid:454)tre(cid:373)el(cid:455) isotonic in the environment (he hopes) and he can move depending on if the environment starts to go hypo or hypertonic. Chemotaxis: best studied in e. coli, bacteria respond to temporal, not spatial, difference in chemical concentration, (cid:862)run and tumble(cid:863) behavior (figure 2. 57, attractants and repellants sensed by chemoreceptors. Directed movement toward an attractant or away from a repellent (^^this happens from a concentration gradient: biased random walk ex.