Environmental Microbiology Exam 3

Taxonomic level 1

Domain

Taxonomic level 2

Phylum

Taxonomic level 3

Class

Taxonomic level 4

Order

Taxonomic level 5

Family

Taxonomic level 6

Genus

Taxonomic level 7

Species

-ales

order suffix

-aceae

family suffix

DNA

deoxyribonucleic acid

Thymine pairs with…

adenine

Adenine pairs with…

thymine

Cytosine pairs with…

guanine

Guanine pairs with…

cytosine

What bond do base pairs use?

Hydrogen

G+C content (%) =

(G+C)/(G+C+A+T) x 100

Actinobacteria G+C

High

Firmicutes G+C

Low

Actinobacteria and Firmicutes are gram…

positive

Actinomycetes are commonly found in…

soil

actinomycetes lack

flagella

Actinomycetes are

filamentousa

actinomycetes produce

hyphae (filaments), forming mycelium

Actinomycete aerial hyphae differentiate into

exospores

What percent of streptomyces produce antibiotics?

50%

How many antibiotics are produced by streptomyces?

Over 500

Streptomyces can produce ____ antibiotics

one or more

How large is a typical streptomyces genome?

greater than or equal to 8Mbp

Antibiotic synthesis requires

many genes

Streptomyces also produces

antifungals and anticancer drugs

In adverse conditions, streptomyces…

• directs nutrients to aerial hyphae

• uses PCD in substrate mycelium

• produces antibiotics to protect released nutrients

Streptomyces filamentous growth G+C content

69-78%

Streptomyces filamentous growth produces

exospores

Streptomyces filaments grow by

hyphal tip extension

Step 1 of streptomyces exospore formation

growth phase

Step 2 of streptomyces exospore formation

Tip curls

Step 3 of streptomyces exospore formation

partitioning of tip

Step 4 of streptomyces exospore formation

cell walls thicken and constrict

Step 5 of streptomyces exospore formation

spores mature

What does streptomyces substrate mycelium produce?

antibiotics and antifungals

What do aerial hyphae form?

exospores

Step 1 of sporulating actinomycetes life cycle

spore germination

Step 2 of sporulating actinomycetes life cycle

vegetative growth

Step 3 of sporulating actinomycetes life cycle

substrate mycelium

Step 4 of sporulating actinomycetes life cycle

antibiotic production & formation of reproductive aerial hyphae

Step 5 of sporulating actinomycetes life cycle

chromosome segregation and septation

Step 6 of sporulating actinomycetes life cycle

spore maturation

Step 7 of sporulating actinomycetes life cycle

spore dispersal

Exospores can

withstand desiccation

Exospores can not

withstand heat

Exospores are dispersed by

wind

What streptomyces spore-bearing structure is this?

Biverticillate with spirals

What streptomyces spore-bearing structure is this?

Biverticillate, no spirals

What streptomyces spore-bearing structure is this?

Monoverticillate with spirals

What streptomyces spore-bearing structure is this?

Closed spirals

What streptomyces spore-bearing structure is this?

Open spirals

What streptomyces spore-bearing structure is this?

Open loops, primitive spirals, hooks

What streptomyces spore-bearing structure is this?

Monoverticillate, no spirals

What streptomyces spore-bearing structure is this?

Flexous

What streptomyces spore-bearing structure is this?

Straight

What streptomyces spore-bearing structure is this?

Fascicled

Streptomyces are primarily found in

soil

Streptomyces are (oxygen requirements)

strict aerobes

Earthy smells come from

geosmin

Streptomyces produce

extracellular enzymes

Streptomyces can

mineralize organic matter

Streptomyces are

mostly free-living, a few pathogens

Nocardia mycelium breaks into

rods and coccoid elements

Nocardia can form

aerial mycelium and conidia

Conidia

asexual, non-motile spores produced by fungi

Nocardia are (oxygen requirements)

strict aerobes

Nocardia are

free-living saprophytes

Saprophytes

organisms that feed on dead and decaying organic matter

Nocardia can degrade

petroleum, hydrocarbons, detergents, benzene, and pesticides

Nocardia may cause

Nocardiosis

Nocardiosis can infect

lungs and central nervous system

Rhodococcus are

soil saprotrophs

Rhodococcus can store

lipids

Rhodococcus can degrade

xenobiotics

Xenobiotics

petroleum hydrocarbons, detergents, benzene, various pesticides, polychlorinated biphenyls

TEM

transmission electron microscopy

Propionibacterium is mainly used in

dairy products (swiss cheese)

What propionibacterium does

ferments sugars

Propionibacterium fermentation produces

CO2 - holes in swiss cheese

Proprionic acid - unique flavor of cheese

Acetic acid

Pyruvate fermentation of sugar lactose produces

lactic acid

Streptococcus Lactobacillus fermentation product

Lactic acid

Cutibacterium is found in

skin and digestive tracts of animals

Cutibacterium on human skin causes

cutibacterium acne and body odor

Frankia forms

nodules in nonleguminous tree species

How many nonleguminous tree species are there?

8

What do Frankia do?

symbiotically fixate nitrogen gas

N2

nitrogen gas

Frankia also produce

hyphae and multilocular sporangia with spores

Mycobacterium looks like

straight or slightly curved rods that sometimes branch or form filaments

Mycobacterium are (oxygen requirements)

aerobic

Mycobacterium have

capsules

Mycobacterium filaments fragment into

rods and coccoid bodies

Mycobacterium growth rate

slowm

Mycobacterium strains causes ___ in humans

tuberculosis and leprosy

Mycobacterium cell walls contain

waxes: mycolic acids, lipids, and polysaccharides linked to peptidoglycan