Wastewater Microbiology and Bacterial Development

Flashcards covering wastewater treatment processes, hydrothermal vent microbiology, social behaviors like quorum sensing and motility, biofilm development, bacteriophage biology, and endospore formation based on lecture notes.

Biochemical Oxygen Demand (BOD)

$$\text{The milligrams of oxygen consumed per L of sample during 5 days of incubation at 20 °C; used as an indicator of organic contaminants in wastewater.}$$

Nitrification

$$\text{The process where bacteria convert ammonia first into nitrite then into nitrate: NH}_3 + \text{O}_2 \rightarrow \text{NO}_3^-$$

Denitrification

$$\text{The process where denitrifying bacteria convert nitrates in soil or water to gaseous nitrogen: NO}_3^- \rightarrow \text{N}_2$$

Activated Sludge Process

$$\text{A secondary biological treatment process involving an aeration tank plus a secondary clarifier that recycles biomass to maintain a sufficient concentration of microorganisms.}$$

Zoogloea spp.

$$\text{A Gram-negative rod-shaped genus known as "living glue" that makes exopolysaccharides (EPS) to hold flocs together and trap toxins or nutrients.}$$

Anaerobic Digestion

$$\text{A biological method of sludge processing where anaerobic bacteria convert organic materials into CO}_2 \text{ and CH}_4\text{ (methane).}$$

Cryptosporidium parvum

$$\text{A protozoan parasite that causes waterborne disease and is notably resistant to chlorine and chlorine dioxide disinfection.}$$

Nitrogen fixation

$$\text{The process where lightning or nitrogen-fixing bacteria combine (fix) nitrogen gas with hydrogen to form ammonia.}$$

Haber-Bosch process

$$\text{The human production of fertilizers by combining nitrogen and hydrogen to synthesize ammonia.}$$

Chemosynthesis

$$\text{The primary production process in deep-sea hydrothermal vents where microbes (thermophilic chemolithoautotrophs) gain energy from oxidizing reduced inorganic compounds.}$$

Beggiatoa

$$\text{A mat-forming sulfur-oxidizing prokaryote that can reach up to 200 microns in diameter and stores elemental sulfur in filaments.}$$

Riftia pachyptila

$$\text{Giant tubeworms found at hydrothermal vents that lack a mouth or stomach and rely on symbiotic bacteria in a specialized organ called the trophosome.}$$

Quorum sensing

$$\text{A cell-to-cell communication mechanism used by bacteria to coordinate group behaviors based on cell density and the concentration of signaling molecules.}$$

LuxI and LuxR

$$\text{The basic components of the Vibrio fischeri quorum sensing system; LuxI is the AHL synthase and LuxR is the transcriptional regulator that binds the signal.}$$

Myxococcus xanthus

$$\text{A Gram-negative soil-dwelling bacterium that engages in social behaviors, including swarming motility and the formation of multicellular fruiting bodies under starvation.}$$

Twitching Motility

$$\text{Social (S) motility that involves Type IV pili extending and retracting to pull the cell forward in a "jerky" motion.}$$

Magnetosome

$$\text{Membrane-bound inclusions of magnetite (Fe}_3\text{O}_4\text{) or greigite (Fe}_3\text{S}_4\text{) that allow magnetotactic bacteria to orient themselves along the Earth's magnetic field.}$

Gas Vesicles

$$\text{Small, gas-filled protein structures that confer buoyancy on phototrophic cells, allowing them to move up and down in the water column.}$$

Biofilm

$$\text{Aggregates of bacteria attached to a surface and/or each other, encased in a self-produced matrix of extracellular polymeric substances (EPS).}$$

Cyclic di-GMP

$$\text{An intracellular signaling molecule that act as a switch to a biofilm lifestyle by increasing cell surface adhesiveness and attachment.}$$

Bacterial Nucleoid

$$\text{A highly compacted, non-membrane-bound region in the center of a prokaryotic cell where the genomic DNA resides.}$$

Carboxysome

$$\text{A proteinaceous organelle that contains carbon fixation machinery (RubisCO) and serves to trap and concentrate CO}_2\text{ for the Calvin Cycle.}$$

Virion

$$\text{An individual viral particle consisting of the genome (DNA or RNA) and its protective protein shell or head.}$$

Lysogeny

$$\text{A phage lifestyle where the viral genome (prophage) integrates into the host bacterial chromosome rather than immediately lysing the cell.}$$

Viral Shunt

$$\text{The process where viral lysis of microbes recycles nutrients and dissolved organic matter back into the environment instead of passing them up the food chain.}$$

CRISPR-Cas System

$$\text{An adaptive bacterial immune system that acquires "memory" of past phage infections by integrating viral DNA fragments as spacers into its own genome.}$$

Endospore

$$\text{A highly resistant, metabolically dormant cell type formed by certain bacteria like Bacillus subtilis in response to extreme nutrient starvation.}$$

Spo0A

$$\text{The master regulator protein that, when phosphorylated (Spo0A~P), initiates the transcriptional program for bacterial sporulation.}$$

Small, Acid-Soluble Proteins (SASPs)

$$\text{Proteins that coat the DNA of an endospore to form a crystalline lattice, providing protection for the genome.}$$