MICR 221 Lecture Notes - Lecture 7: Pilus, Bacterial Adhesin, Gram-Negative Bacteria

• School: Queen's University
• Department: Microbiology and Immunology
• Course: MICR 221
• Professor: Eric B Carstens

Document Summary

Bacterial proteinaceous appendages: locomotion: flagella, adherence factors: pili or fimbriae (mainly adherance, conjugal transfer of dna: sex pili. Pili: widespread in gram negatives, rare in gram positives. 100-300 per cell, peritrichous (located all around cell) Have to assemble on the outside of the membrane. Single operon: one promoter that drives the synthesis of mrna. Problem for cell is that it needs 1000 copies of a but only tiny amounts of the rest of the proteins. What happens: rna polymerase starts at a and there is a transcriptional terminator between a and h. Means that most of the time the transcription factor will fall off after a. Very small percent of the time the transcription factor will stay one and transcribe rest of genes. Result: lots of mrna that encode a, and small amnts of rest of the protein. How manages to accomplish this while still using a single promoter. Not all bacteria have the ability to make flagella.