Bacterial Differentiation, Biofilms, and Antibiotic Resistance

Vocabulary terms and definitions covering Anabaena heterocyst differentiation, biofilm regulation via c-di-GMP and Vibrio cholerae factors, antibiotic resistance and persistence, and bacterial cell shape and division machinery.

Photosystem II (Anabaena)

A photosynthetic system that generates oxygen, which poses a threat to nitrogen fixation because nitrogenase is oxygen-sensitive.

Heterocyst Envelope

A specialized boundary in Anabaena that thickens to limit oxygen entry and protect oxygen-sensitive nitrogenase.

PatS

A signaling factor in Anabaena that produces inhibitory signals to space heterocysts along the filament and prevent too many nearby cells from forming heterocysts.

HetR

A positive regulator in Anabaena that promotes heterocyst differentiation.

Vegetative Cells (Anabaena)

Filament cells that supply fixed carbon and reducing power to neighboring heterocysts to support nitrogen fixation.

PatA

A regulatory protein in Anabaena that promotes HetR activity and decreases PatS activity, thereby favoring heterocyst formation.

Surface Attachment Proteins

Cell surface structures required for initial attachment, which can trigger biofilm-related genes and subsequent biofilm development.

Diguanylate Cyclase

An enzyme that synthesizes c-di-GMP; elevated activity raises intracellular c-di-GMP to favor attachment and biofilm matrix production.

Phosphodiesterase

An enzyme responsible for degrading and breaking down c-di-GMP; loss of its activity causes c-di-GMP to accumulate.

VpsR and VpsT

Positive regulatory proteins in Vibrio cholerae that activate transcription of biofilm matrix genes.

HapR

A repressor protein in Vibrio cholerae that negatively regulates biofilm formation.

RNA Polymerase

The enzyme responsible for the transcription of DNA into RNA, which can be directly targeted and inhibited by specific antibiotics.

Target Modification

A mechanism of antibiotic resistance in which a mutation alters the drug binding site while preserving normal function, causing the antibiotic to bind less effectively.

Antibiotic Efflux Pumps

Active transport systems that export antibiotics out of the bacterial cell, decreasing the intracellular concentration of the drug.

Persister Cells

Genetically antibiotic-sensitive bacteria that transiently survive lethal drug exposure by entering dormancy or low metabolic activity without acquiring inherited resistance.

Antibiotic Persistence

The temporary survival of dormant bacteria during antibiotic treatment, where cells regrow after drug removal and their descendants remain fully susceptible.

FtsI

A bacterial division protein required for division wall synthesis and septum construction.

MreB

A bacterial cytoskeletal protein that organizes rod-shaped cell wall elongation and maintains rod morphology.