Bacteria and Archea Exam 2 Eco Evo

Peptidoglycan

Material in bacterial cell walls made of polysaccharide chains cross-linked by peptides.

Phospholipid

Lipid molecule that forms a major component of cell membranes.

Lipid bilayer

Double layer of lipids that forms a membrane.

Ether linkage

Bond connecting archaeal membrane lipids to glycerol.

Ester linkage

Bond connecting bacterial and eukaryotic membrane lipids to glycerol.

Branched isoprene chains

Branched lipid tails characteristic of archaeal membranes.

Unbranched fatty acids

Lipid tails characteristic of bacterial and eukaryotic membranes.

Gram-positive bacteria

Bacteria with thick peptidoglycan cell walls that typically stain purple.

Gram-negative bacteria

Bacteria with thin peptidoglycan cell walls and an outer membrane that typically stain pink.

Endospore

Tough, resistant structure formed by some bacteria.

Antibiotic resistance

Ability of bacteria to survive treatment with antibiotics.

Actinomycetota (formerly Actinobacteria)

Gram-positive bacteria with high GC content; many are soil organisms, and some produce antibiotics.

Bacillota (formerly Firmicutes)

Gram-positive bacteria with low GC content; some form endospores, and others are important in the human gut.

Pseudomonadota (formerly Proteobacteria)

Highly diverse Gram-negative bacteria, including E. coli, nitrogen-fixing Rhizobium, and important pathogens.

Bacteroidota (also called Bacteroidetes)

Gram-negative bacteria commonly found in the environment and human gastrointestinal tract; many degrade complex organic matter.

Cyanobacteriota (also called Cyanobacteria)

Aquatic, Gram-negative photoautotrophs that produced oxygen that changed Earth's atmosphere; some fix nitrogen, and some cause harmful algal blooms.

Escherichia coli (E. coli)

Important model organism belonging to Pseudomonadota; Gram-negative.

Staphylococcus aureus

Gram-positive bacterium used in the slides as an example of Gram staining.

Rhizobium

Bacteria that fix nitrogen within plant roots.

Agrobacterium tumefaciens

Bacterium associated with crown gall disease in plants.

Chondromyces

Bacterial genus whose members can form fruiting bodies.

Bacteroides fragilis

Bacterium that normally lives in the human gastrointestinal tract but can become pathogenic under certain conditions.

Bifidobacterium adolescentis

Bacterium associated with the human gut; the slides discuss Bifidobacteria in infant guts and probiotics.

Clostridium

Bacterial genus containing species that can form tough endospores.

Bacillus

Bacterial genus containing species that can form tough endospores.

Helicobacteria

Group listed in the slides as an example of photoheterotrophs.

Purple sulfur bacteria

Bacteria shown as examples of photoautotrophs.

Purple non-sulfur bacteria

Bacteria shown as examples of photoheterotrophs.

Green non-sulfur bacteria

Bacteria shown as examples of photoheterotrophs.

Cycloclasticus pugetii

Bacterium that specializes in degrading toxic polycyclic aromatic hydrocarbons (PAHs).

C. difficile

Bacterium mentioned in the slides in the context of probiotics and human health.

H. pylori (Helicobacter pylori)

Bacterium mentioned in the slides in the context of infection and human health.

Methanobacteriati

Archaeal group associated with methane cycling, hydrocarbon degradation, sulfur, nitrogen, and iron cycling, organic matter degradation, and marine carbon cycling.

Asgard archaea

Archaeal group relevant to eukaryotic ancestry; members have pathways related to ester-linked membrane lipids similar to those of Bacteria and Eukarya.

Nanobdellati

Archaeal group that includes obligate symbionts with reduced genomes; some are associated with acidic environments.

Thermoproteati

Archaeal group often found in sulfur-rich hot springs, acidic environments, and deep-ocean sediments; includes chemoautotrophs and anaerobic heterotrophs.

Methanopyrus kandleri

Archaeon highlighted for its ability to grow at 122°C under high pressure; the slides identify it as holding the known upper thermal limit for life.

Nanoarchaeum equitans

Archaeon with one of the smallest known genomes; an obligate symbiont of a larger archaeon.

Ignicoccus

Larger archaeal host associated with Nanoarchaeum equitans.

Sulfolobus

Archaeal genus with species that live in sulfur-rich hot springs.

Nitrosopumilus maritimus

Ammonia-oxidizing archaeon highlighted as the first cultured non-thermophilic archaeon in the slides.

Lokiarchaeota

Asgard archaeal group highlighted for its potential relationship to eukaryotic ancestry; its first genome was constructed from sediments near Loki's Castle hydrothermal vent field.

Methanogen

Microorganism that produces methane.

Anaerobic methanotroph

Organism that consumes methane under anaerobic conditions.

Halophile

Organism adapted to high-salt environments.

Acidophile

Organism adapted to acidic environments.

Thermophile

Organism adapted to high temperatures.

Extremophile

Organism adapted to environmental conditions that are extreme for many other organisms.

Obligate symbiont

Organism that must live in a close association with a host or partner.

Symbiosis

Close association between different organisms.

Syntrophy

Metabolic cooperation between organisms in which one organism's products support another.

Biofilm

Community of microorganisms attached to a surface and embedded in a surrounding matrix.

CRISPR

System that can provide defense against viruses in microorganisms.

Ammonia oxidation

Conversion of ammonia into oxidized nitrogen compounds; performed by some archaea.

Hydrothermal vent

Seafloor opening that releases heated, mineral-rich fluids.

Biogeochemical cycle

Movement of elements through organisms and the environment.

Methane cycle

Movement and transformation of methane through biological and environmental processes.

Bioremediation

Use of organisms to break down pollutants or help repair environmental damage.

Polycyclic aromatic hydrocarbons (PAHs)

Toxic organic compounds that certain microorganisms can degrade.

Harmful algal bloom

Rapid growth of certain aquatic organisms that can cause harmful environmental effects.

Probiotic

Live microorganism associated with potential health benefits.

Antibiotic

Substance used to kill or inhibit bacteria.

Pathogen

Organism that can cause disease.