Ch 16: Bacterial Diversity (Bio 286 - Microbiology) Flashcards
common traits of bacteria
central apparatus of gene expression: RNA polymerase, ribosomal RNAs, translation factors; cells walls made of peptidoglycan
gram positive bacteria
rods and cocci; no outer membrane; thick cell wall with peptidoglycan; many are pathogens; include staphylococcus, streptococcus, and Listeria
Listeria
polymerizes actin inside host cell
(Gram positive) Lactobacillales
key genera: Lactobacillus and Streptococcus; non-sporulating, oxidase-/catalase-negative fermentative rod bacteria that produce lactic acid; widely used in food production and preservation; obtain energy only by substrate-level phosphorylation; aerotolerant anaerobes (not sensitive to oxygen); homofermentative produce only lactic acid while heterofermentative produce ethanol, CO2, and lactate
lactobacillales
aerotolerant anaerobes
(Gram positive) lactobacillus
make yogurt, milk, bread
(gram positive) streptococcus
causes strep throat and cavities
(gram positive) leuconostoc
on cabbage and makes sauerkraut
(gram positive) nonsporulating bacillales and clostridiales
key genera: Listeria, Staphylococcus, Sarcina Listeria; in the order of Bacillales; found widely in soils; opportunistic pathogen that causes foodborne illnesses; catalase-positive rod shaped; facultatively aerobic chemoorganotrophs; often grow well at low temperatures
(gram positive) staphylococcus
facultative aerobe that respires but can ferment; grows in clusters; CATALASE-POSITIVE; resistant to reduced water potential and tolerate drying in high salt (NaCl); common commensals and parasites of humans/animals that occasionally cause serious infections
staphylococcus
tolerate drying from high salt
(gram positive) sporulating bacillales and clostridiales
key genera: Bacillus, Clostridium, Sporosarcina; distinguished on basis of cell morphology, shape, and cellular position of endospore, relationship to oxygen, and energy metabolism,; generally found in soils; pathogenic species are saprophytic and infect animals incidentally; endospores are advantageous for soil microorganisms because of variations in nutrient levels/temperature/water activity
(Gram positive) Bacillales/Clostridiales
endospore forming bacteria
gram positive endospores
extremely heat resistant; spore forms inside mother cell
(gram positive) Clostridium
toxin formers of tetanus, botox, and gangrene
(gram positive) Bacillus
toxin formers of Anthrax, Bt
(gram positive) Bacillus and Paenibacillus
many produce extracellular hydrolytic enzymes that break down polymers (polysaccharides, nucleic acids, lipids); many bacilli produce antibiotics, while others produce toxic insecticidal proteins
(gram positive) Clostridium
lacks a respiratory chain and obtains ATP by substrate-level phosphorylation; SACCHAROLYTIC ferment surgars; PROTEOLYTIC ferment amino acids or amino acid pairs (stickland reactions); mainly found in anaerobic pockets in soil or mammalian intestinal tract; some are pathogenic causing botulism, tetanus, and gangrene
saccharolytic clostridium
ferment sugars
proteolytic clostridium
ferment amino acids or amino acid pairs (stickland reactions)
clostridium
causes botulism, tetanus, and gangrene
(gram positive) tenericutes (the mycoplasmas)
key genera: Mycoplasma, Spiroplasma; lack cell walls; some of smallest organisms; related to Firmicutes (nonsporulating bacillus and clostridia); typically live in close association with animal and plant hosts; small genomes
(gram positive) firmicutes
nonsporulating bacillus and clostridium; low G+C content
(gram positive) mycoplasmas
small, pleomorphic cells; colonies show a characteristic “fried egg” appearance
(gram positive) actinobacteria
key genera: Arthrobacter, Corynebacterium, Propionibacterium; rod-shaped to filamentous, usually aerobic inhabitants of soil and plant materials; mostly harmless commensals with exception of Mycobacterium; valuable for antibiotics and certain fermented dairy products; have a higher GC composition in DNA
actinobacteria
acid fast cell walls (waxy lipids in cell wall); many form long/multicellular filaments; aerial mycelia carry arthrospores
(gram positive) streptomyces
very large genome; source of many antibiotics :)
gram-negative proteobacteria
largest group of cultured organisms with six major classes; many metabolic activities (purple light receptors, use of inorganic electron donors, highly adaptable metabolism)
proteobacteria
largest group of cultured organisms
(gram negative) alpha proteobacteria
photoheterotrophs (Rhodospirillum) ; endosymbionts (Rhizobium, Agrobacterium, Rickettsias)
alpha proteobacteria
most genetically similar to mitochondria
(gram negative) rhizobium
fixes nitrogen; found in root nodules
(gram negative) agrobacterium
pathogen of plants causing plant tumors
(gram negative) rickettsias
obligate intracellular parasites causing Rocky Mountain Spotty Fever
(gram negative) beta proteobacteria
lithotrophs: nitrate/sulfur/iron oxidizers, nitrosomes; pathogens: burkholderia, Neisseria gonorrhoeae
nitrosomes
beta proteobacteria used in wastewater treatment
(gram negative) Neisseria gonorrhoeae
sexually transmitted disease
(gram negative) gamma proteobacteria
lithotrophs; some are phototrophs (purple sulfur bacteria, Chromatium - deposits sulfur inside cell, Thiocapsa - uses nitrite as electron donor); use of iron or H2S as electron donor
(gram negative) enteric gamma proteobacteria
facultatively anaerobic rods where many are motile and many form biofilms- includes Escherichia coli and pathogens: salmonella, proteus, shigella; can also be aerobic rods that are in biofilms or pathogens including pseudomonas and Legionella
enteric gamma proteobacteria
Escherichia coli
(gram negative) delta proteobacteria
Myxococcus xanthus, Bdellovibrio bacteriovorus
(gram negative delta proteobacteria) Myxococcus xanthus
attacks other bacteria in “packs” which exhibits social movement; aggregates into fruiting bodies; disperses myxospores
(gram negative delta proteobacteria) Bdellovibrio bacteriovorus
parasitizes other bacteria (E. coli); grows in periplasm; lyses the host
(gram negative) Epsilon proteobacteria
smallest group of proteobacteria; Helicobacter pylori CAUSES STOMACH ULCERS (burrows below protective mucous layer)
(gram negative) nitrospirae
spiral shape; most oxidize nitrite to nitrate (Nitrospira), while Leptospirillum oxidizes iron and fixes carbon
(gram negative) bacteriodetes and chlorobi
OBLIGATE ANAEROBES; bacteriodes (major flora of human colon, break down toxins in food to provide food) and CHLOROBIUM (green sulfur bacterium)
(gram negative) chlorobium
obligate anaerobe that is a green sulfur bacterium
(gram negative) spirochetes
flexible/narrow spiral shape; flagella at ends but fully enclosed within periplasm to form axial filament… flagellar rotation turns cell
(gram negative) Chlamydiae
sexually transmitted disease and can cause blindness; obligate intracellular parasites that exist in the forms large reticulate body and small elementary bodies
reticulate body of Chlamydiae
grows within cells but cannot survive outside of host
elementary bodies of Chlamydiae
the form that infects new host cells; survives outside of host cells to be transferred to new host, similar in function to spores
(gram negative) planctomycetes
multiple internal membranes (a double membrane surrounds the nucleoid but does not make a nucleus because ribosomes are also within enclosed space); verrocomicrobia: irregular shape, contains tubulin
(gram negative) Cyanobacteria
oxygenic phototrophs; many fix nitrogen (specialized cell types); have subcellular structures thylakoids, carboxysomes, and gas vesicles; can secrete protective mucilage; many grow as filaments (multiple cells growing in a line) while others grow as colonies; many form akinetes
cyanobacteria
oxygenic phototrophs
thylakoids (of cyanobacteria)
site of photosynthesis; similar to chloroplasts
carboxysomes (of cyanobacteria)
lipid bodies
akinetes
specialized spore cells produced by cyanobacteria that survive long periods of dry to germinate later
chloroflexi
green nonsulfur bacteria; filamentous phototrophs, live at high temperatures (thermophiles); many have chromosomes (membrane bound organelles that contain chlorophyll)
deinococcus-thermus
aerobic chemoorganotrophs; stain gram positively but have gram negative cell wall structure containing several layers but lacking lipid A and containing ormithine instead of diaminopimelic acid
(thermales) thermus aquaticus
model for life at high temperatures and is source of Taq DNA polymerase for PCR (polymerase chain reaction)
Deinoccoccus radiodurans
radiation and desiccation resistant; most are red/pink from carotenoids; resistant to most mutagenic agents
Wolbachia
intracellular parasites of arthropods (crustaceans and insects)
mycoplasma lack cell walls
so they frequently exist as obligate symbionts
Neisseria gonorrhoeae
causes gonorrhea, a sexually transmitted disease
