Lecture 7a: Microbial diversity block cards

Memorize phylum 1st, then individual bacteria

What are the defining characteristics of Tenericutes?

• Phylogenetically related to Gram-positive bacteria.

• lack a cell wall.

• described as Gram-negative in the lecture.

• often pleomorphic (variable shapes).

What are the defining characteristics of Actinobacteria?

• Gram-positive and high-GC bacteria.

• includes club-shaped coryneform bacteria and propionic acid bacteria and filamentous forms and mycobacteria.

What are the defining characteristics of Bacteroidetes?

• Large and heterogeneous phylum of Gram-negative bacteria.

• includes aerobes and anaerobes.

• few unifying characteristics.

• important members inhabit the human large intestine.

What are the defining characteristics of Acidobacteria?

• Difficult to cultivate.

• very little is known about them.

• can make up 20–50% of soil microbial communities.

• first genome sequenced in 2009.

What are the defining characteristics of Chlamydiae?

• Gram-negative cell wall type but lack peptidoglycan.

• obligate intracellular parasites.

• unique life cycle with elementary bodies and reticulate bodies.

What are the defining characteristics of Planctomycetes?

• Budding and appendaged bacteria.

• protein stalks used for attachment.

• two membrane bound compartments and peptidoglycan.

What are the defining characteristics of Cyanobacteria?

• All perform oxygenic photosynthesis.

• all are autotrophs that fix CO₂ through the Calvin cycle.

• have thylakoid membranes.

• Gram-negative cell wall type containing peptidoglycan.

• can be unicellular and filamentous or branching filamentous.

• some form nitrogen-fixing heterocysts.

What are the defining characteristics of Proteobacteria?

• Gram-negative phylum.

• most metabolically diverse bacterial phylum.

• includes chemolithotrophs and chemoorganotrophs and phototrophs.

• some are facultative and can switch metabolic lifestyles.

• six classes: Alpha and Beta and Gamma and Delta and Epsilon and Zeta.

What are the defining characteristics of Firmicutes?

• Gram-positive and low-GC bacteria.

• includes lactic acid bacteria and endospore-formers.

• lactic acid bacteria are aerotolerant anaerobes that produce lactic acid through fermentation.

What are the defining characteristics of deeply branching hyperthermophilic bacteria?

• Include bacteria that thrive at extremely high temperatures.

• their deep branching positions suggest LUCA may have been a hyperthermophile.

What are the defining features of Alphaproteobacteria?

• Includes both pathogens and non-pathogens.

• examples include nitrogen-fixing symbionts and obligate intracellular pathogens.

What are the defining features of Betaproteobacteria?

• Metabolically diverse.

• includes both pathogenic and non-pathogenic species.

What are the defining features of Gammaproteobacteria?

• Metabolically and ecologically diverse.

• many grow well in the laboratory and are important research models.

What are the defining features of Deltaproteobacteria?

Includes unusual bacteria such as predators and gliding bacteria and fruiting-body formers and sulfate reducers.

What are the defining features of Epsilonproteobacteria?

Small class containing microaerophilic and spirillum-shaped pathogens.

What are the defining features of Zetaproteobacteria?

• Barely studied.

• one known species: Mariprofundus ferrooxydans.

What are the important characteristics of Mycoplasma genitalium?

• Phylum: Tenericutes.

• Lacks a cell wall.

• often pleomorphic.

• causes urethritis and pelvic inflammatory disease.

• first free-living bacterium to have its genome sequenced.

• very small genome (~500 kbp).

What are the important characteristics of Mycobacterium tuberculosis?

• Phylum: Actinobacteria

• Modified Gram-positive cell wall with mycolic acids outside peptidoglycan. acid-fast.

• causes tuberculosis.

• slow-growing, colonies can take weeks to form.

What are the important characteristics of Corynebacterium diphtheriae?

• Phylum: Actinobacteria.

• Coryneform (club-shaped).

• produces an exotoxin that inhibits protein synthesis.

• causes diphtheria and respiratory tissue death and potentially suffocation.

What are the important characteristics of Propionibacterium acnes?

• Phylum: Actinobacteria.

• Propionic acid bacterium.

• can be found on the human body.

• non-pathogenic

What are the important characteristics of Propionibacterium freudenreichii?

• Phylum: Actinobacteria.

• Found in milk. associated with Swiss cheese.

• propionate (flavour) and CO₂ (holes).

What are the important characteristics of Streptomyces griseus?

• Phylum: Actinobacteria.

• Filamentous Gram-positive bacterium.

• forms branching hyphae and mycelia.

• produces conidia for dispersal.

• produces streptomycin and an antibiotic that inhibits protein synthesis.

What are the important characteristics of Bacteroides thetaiotaomicron?

• Phylum: Bacteroidetes.

• Strict anaerobe.

• dominant microbe in the human large intestine.

• produces enzymes that degrade polysaccharides and helps digest a wider variety of plant polymers.

What are the important characteristics of Gemmata obscuriglobus?

• Phylum: Planctomycetes.

• Budding and appendaged bacterium.

• internal membrane-bound compartments.

• contains peptidoglycan

What are the important characteristics of Chlamydia trachomatis?

• Phylum: Chlamydiae.

• Obligate intracellular parasite.

• has elementary-body and reticulate-body stages.

• causes trachoma (eye infection) and which can cause scarring and blindness.

What are the important characteristics of Prochlorococcus?

• Phylum: Cyanobacteria.

• Performs oxygenic photosynthesis.

• autotroph that fixes CO₂.

• one of the most abundant organisms on Earth. accounts for approximately half of photosynthesis in the world’s oceans.

What are the important characteristics of Rhizobium leguminosarum?

• Phylum: Proteobacteria.

• class: Alphaproteobacteria.

• Forms root nodules on legume plants.

• symbiotic relationship.

• fixes nitrogen into a bioavailable form.

• plant provides nutrients and a home.

What are the important characteristics of Rickettsia rickettsii?

• Phylum: Proteobacteria.

• class: Alphaproteobacteria.

• Obligate intracellular pathogen. transmitted through insect bites.

• causes Rocky Mountain spotted fever.

• closest phylogenetic relative of the eukaryotic mitochondrion.

What are the important characteristics of Neisseria mucosa?

• Phylum: Proteobacteria.

• class: Betaproteobacteria.

• Non-pathogenic commensal that lives on human mucous membranes.

What are the important characteristics of Neisseria gonorrhoeae?

• Phylum: Proteobacteria.

• class: Betaproteobacteria.

• Pathogenic bacterium that causes gonorrhea.

What are the important characteristics of Escherichia coli?

• Phylum: Proteobacteria.

• class: Gammaproteobacteria.

• Gram-negative rod.

• facultative aerobe.

• peritrichous flagella.

• ferments lactose into acids and alcohols.

• lives in the large intestine of warm-blooded animals.

• indicator of fecal contamination.

What are the important characteristics of Pseudomonas aeruginosa?

• Phylum: Proteobacteria.

• class: Gammaproteobacteria.

• Gram-negative rod.

• polar flagella.

• does not ferment sugars.

• naturally resistant to many antibiotics and disinfectants.

• opportunistic pathogen and especially in immunocompromised patients.

• can cause respiratory infections in cystic fibrosis patients.

What are the important characteristics of Myxococcus xanthus?

• Phylum: Proteobacteria.

• class: Deltaproteobacteria.

• Gliding motility (A and S forms).

• predatory and releases exoenzymes to lyse other bacteria.

• starvation triggers aggregation into multicellular fruiting bodies.

• cells differentiate into myxospores for dispersal.

What are the important characteristics of Bdellovibrio bacteriovorus?

• Phylum: Proteobacteria.

• class: Deltaproteobacteria.

• Curved and highly motile predator.

• attacks other Proteobacteria and Gram-negative bacteria. penetrates the cell wall.

• multiplies in the periplasm.

• obtains macromolecules directly from its host.

What are the important characteristics of Desulfovibrio?

• Phylum: Proteobacteria.

• class: Deltaproteobacteria.

• Sulfate reducer.

• obligate anaerobe.

• some species contribute to oil well souring.

What are the important characteristics of Campylobacter jejuni?

• Phylum: Proteobacteria.

• class: Epsilonproteobacteria.

• Microaerophilic.

• spirillum-shaped.

• frequently transmitted through undercooked chicken.

• common cause of food-borne illness.

• causes gastroenteritis and bloody diarrhea.

What are the important characteristics of Lactobacillus delbrueckii?

• Phylum: Firmicutes.

• Lactic acid bacterium.

• aerotolerant anaerobe.

• produces lactic acid through fermentation.

• used in yogurt production.

What are the important characteristics of Streptococcus pyogenes?

• Phylum: Firmicutes.

• Lactic acid bacterium.

• can cause strep throat and scarlet fever and flesh-eating disease.

What are the important characteristics of Staphylococcus aureus?

• Phylum: Firmicutes.

• Facultative aerobe.

• forms grape-like clusters.

• lives on skin.

• halotolerant.

• ferments mannitol and producing acid and turning mannitol salt agar yellow. frequent cause of hospital-acquired infections.

What are the important characteristics of Staphylococcus epidermidis?

• Phylum: Firmicutes.

• Normal skin commensal.

• does not produce acid on mannitol salt agar and so the medium remains pink.

What are the important characteristics of Bacillus subtilis?

• Phylum: Firmicutes.

• genus: Bacillus.

• Aerobic endospore-former.

• important laboratory model for Gram-positive cell structure and genetics and cell division and endospore differentiation.

What are the important characteristics of Clostridium botulinum?

• Phylum: Firmicutes.

• genus: Clostridium.

• Strict anaerobe with fermentative metabolism.

• lives in anoxic soil pockets.

• can grow in anaerobic canned foods.

• produces a deadly neurotoxin that causes botulism.

• proper canning must destroy endospores or prevent germination.

What are the important characteristics of Thermus aquaticus?

• hyperthermophilic bacteria.

• Thermophilic chemoorganoheterotroph.

• source of Taq DNA polymerase.

• temperature-stable Taq is essential for PCR.

What are the important characteristics of Deinococcus radiodurans?

• Hyperthermophilic bactera

• Extremely resistant to radiation.

• highly effective DNA repair.

• forms pairs or tetrads.

• nucleoids from two cells can fuse to facilitate repair after massive DNA damage.

• Gram-negative cell wall type but stains Gram-positive due to thick peptidoglycan

Filamentous Actinobacteria

• Phylum: Actinobacteria

• form branching filaments called hyphae, which can develop into a network called mycelium

• many are soil dwelling

• some produce antibiotics