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MBIO1010 > Lecture Set 4 : Part 2 > Flashcards

Lecture Set 4 : Part 2 Flashcards

1
Q

what are the proteobacteria?

A

-most metabolically diverse bacteria phylum
-includes many of the most commonly encountered bacteria (very large)
-major group of gram negatives (can be considered the most typical, although some deviation occurs)

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2
Q

what makes the proteobacteria metabolically diverse?

A

-contains chemolithotrophs, chemoorgantrophs, and anoxygenic phototrophs
-many are also facultative organisms so they can switch from one metabolic lifestyle to another based on whats available or not available

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3
Q

what are some of the different classes within proteobacteria?

A

-alphaproteobacteria
-betaproteobacteria
-gammaproteobacteria
-deltaproteobacteria
-epsilonproteobacteria

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4
Q

what is the alphaproteobacteria class?

A

-class of the proteobacteria phylum
-includes both pathogens and non-pathogens

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5
Q

what is an example of a non-pathogen in the alphaproteobacteria class? what are some characteristics?

A

-rhizobium leguminosarum
-forms root nodules on legume plants
-has a symbiotic relationship with these plants (both benefit)
-bacterium fixes nitrogen into a bioavailable form
-plant provides nutrients and a home for the bacteria

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6
Q

what is an example of a pathogen in the alphaproteobacteria class? what are some characteristics?

A

-rickettsia rickettsii
-obligate intracellular pathogen (closest relative to the mitchondria = endosymbiotic theory)
-carried by insects and transmitted in their bites
-causes rockey mountain spotted fever

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7
Q

what is the betaproteobacteria class?

A

-class of the proteobacteria phylum
-very metabolically diverse
-includes both pathogens and non-pathogens

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8
Q

what is an example of a pathogen in the betaproteobacteria class?

A

-neisseria gonorrhoeae
-causes the STI gonorrhea

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9
Q

what is an example of a non-pathogen in the betaproteobacteria class?

A

-commensal with the human body (bacteria gains but human body neither gains nor loses)
-lives on mucous membranes

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10
Q

what can be noticed with the pathogen and non-pathogen examples of the alphaproteobacteria and betaproteobacteria?

A

-those in the alphaproeobacteria do not share a genus name
-those in the betaproteobacteria do share a genus name
-shows that you cannot define what is and is not a pathogen using phylogenetics

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11
Q

what is the gammaproteobacteria class?

A

-class of the proteobacteria phylum
-metabolically and ecologically diverse
-many grow well in lab and have become important research models

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12
Q

what are 2 examples under the gammaproteobacteria class?

A

-E.coli
-pseudomonas aeruginosa

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13
Q

what are the characteristics of E.coli?

A

-rod shaped, facultative anaerobe, gram negative bacteria that is motile by the means of peritrichous flagella
-can ferment lactose very strongly to a mixture of acids and alcohols (macconkey agar)
-lives in the large intestine of warm-blooded animals
-serves as an important indicator of fecal contamination

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14
Q

what are the characteristics of pseudomonas aeruginosa?

A

-rod shaped gram negative bacteria that is motile by the means of polar flagella (lophotrichous)
-naturally resistant to many antibiotics and disinfectants
-is an opportunistic pathogen

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15
Q

what does it mean when we say that pseudomonas aeruginosa is an opportunistic pathogen?

A

-causes infections in immunocompromised patients (respiratory tract infections in cystic fibrosis patients)
-can only become pathogenic in the right conditions
-not considered weak by any means

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16
Q

what is the deltaproteobacteria class?

A

-class of the proteobacteria phylum
-contains many species with strange behaviours

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17
Q

what are 2 examples under the deltaproteobacteria class?

A

-myxobacteria (myxococcus xanthus)
-bdellovibrio bacteriovorus

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18
Q

what are the characteristics of myxococcus xanthus?

A

-has gliding motility
-it is a predatory bacteria
-when it becomes starved, its cells migrate together to form complex multicellular fruiting bodies
-an individual subset of cells within the fruiting body then differentiate into myxospores for dispersal

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19
Q

what is the predatory adaptation of the myxococcus xanthus?

A

-release exoenzymes to lyse other bacteria for nutrients

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20
Q

what are the characteristics of bdellovibrio bacteriovorus?

A

-have a curved shape (fibro = curve)
-does not divide by binary fission (one cell into two)
-divides by multiple fission (one cell into many cells)
-highly motile
-predator of other proteobacteria and other gram negative bacteria
-parasitic (uses macromolecules obtained directly from the host

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21
Q

what is the predatory behaviour of bdellovibrio bacteriovorus?

A

-attaches to and penetrates the cell wall and breaks down peptidoglycan so it loses its structure
-the outer membrane then forms a bubble around the prey and the bdellovibrio bacteriovorus due to the loss of shape
-then multiples inside the periplasm and causes cell lysis to release its progeny
-can also become parasitic

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22
Q

what is the cyanobacteria phylum?

A

-also known as blue/green algae
-has impressive morphological diversity
-mostly gram negative
-can go through binary or multiple fission
-generally larger than other bacteria
-some can form heterocysts which are specialized nitrogen fixing cells
-most carry out oxygenic photosynthesis
-they are autotrophs
-wide habitat distribution
-lowest nutritional requirements of any organisms

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23
Q

what makes cyanobacteria morphologically diverse?

A

-cyanobacteria can take on many forms
-can be unicellular, filamentous, or branching filamentous

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24
Q

why are cyanobacteria similar to chloroplasts? what makes them different?

A

-they both carry out photosynthesis in specialized membranes called thylakoids
-cyanobacteria has cell walls whereas chloroplasts do not

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25
what is oxygenic photosyntheiss?
-harvesting energy from light to produce oxygen
26
what do autotrophs do?
-fix CO2 to build cell material (through the calvin cycle)
27
what habitats are cyanobacteria distributed in?
-terrestrial -freshwater -marine
28
why does cyanobacteria have low nutritional requirements?
-primary producers for different ecosystems -can fix carbon and nitrogen -can make growth factors on their own -only need CHOPKNSCaFeMg
29
what is an example of cyanobacteria?
-prochlorococus -one of the most abundant organisms on earth -accounts for half of the photosynthesis in the worlds oceans
30
what is the firmicutes phylum?
-one of two phyla with gram positive cell walls -considered the low GC gram positives (less GC in their DNA sequences) -includes the lactic acid as well as non-lactic acid bacteria -also includes endospore formers -has a small inclusion of gram negatives, as well as gram negative endospore formers
31
what are lactic-acid bacteria?
-aerotolerant anaerobes that produce lactic acid as an end product of fermentation
32
what are examples of lactic acid bacteria?
-lactobacillus delbrueckii (yogurt production) -streptococcus pyogenes (strep throat, scarlet fever, flesh eating disease) (strain + virulence factor dependent)
33
what is an example of a non-lactic acid bacteria?
-staphylcoccus aureus -facultative anaerobe that forms grape-like clusters -lives on the skin (likely in nose) -halotolerant bacteria (can be isolated on mannitol salt agar) -frequent cause of nosocomial infections
34
what is a nosocomial infection?
-infection acquired in a hospital setting -coming and going of different sicknesses and disease
35
what are the best genus' of endospore formers?
-bacillus (aerobic) -clostridium (anaerobic, strict)
36
where are endospore formers primarily found?
-in soil -most are non-pathogenic saprophytic soil organisms -some can be very dangerous pathogens
37
what does it mean to be saprophytic?
-break down and recycle complex organic molecules
38
what is an example of a gram negative firmicute? what does this suggest?
-veillonella parvula -suggests that gram positive firmicutes arose from a gram negative ancestor
39
what is proteomic modelling?
-viewing all of the proteins within a sample
40
what genus are the gram negative endospore formers closely related to? what is an example
-clostridium -ex: sporomusa malonica
41
what is the tenericutes phylum?
-the mycoplasmas -phylogenetically gram positive -lacking a cell wall (stain gram negative) and teichoic acids -still contain steriles -often pleomorphic as they lack the structure that a cell wall provides (no characteristic morphology)
42
what is an example of tenericutes?
-mycoplasma genitalium -very small bacteria -common cause of urethritis and pelvic inflammatory disease -first free living bacterium to have its genome sequenced
43
why was mycoplasma genitalium the first to have its genome sequenced?
-has one of the smallest genomes known (500kbp)
44
what is characteristic about how mycoplasma genitalium grow on agar?
-colonies penetrate down -"fried egg" look
45
what are the 2 main phyla of gram positive bacteria?
-firmicutes -actinobacteria
46
what is the actinobacteria phylum?
-one of two phyla with gram positive cell walls -considered the high GC gram positives (more GC in their DNA sequences) -includes coryneform bacteria (club shaped) -includes mycobacterium -includes a genus of filamentous gram positive bacteria (streptomyces)
47
what is an example of a coryneform bacteria within the actinobacteria?
-corynebacterium diphtheriae -produces an exotoxin that inhibits protein synthesis -causes tissue death in the respiratory tract (diptheria - have a standard vaccine) -can lead to death by suffocation
48
what is an example of a mycobacteria within the actinobacteria?
-mycobacterium tuberculosis -slow growing (24hr for 1 gen) -colonies can take weeks to form on an agar medium -cause of tuberculosis (slow fatal respiratory disease)
49
what are the characteristics of mycobacteria?
-have a modified gram positive cell wall -layer of mycolic acids outside the peptidoglycan layer (wont stain with the gram stain) -makes them an acid fast bacteria
50
what are the characteristics of streptomyces?
-filamentous gram positive bacteria that forms branching hyphae and mycelia -most are obligate aerobes -live in well aerated soils (give soil its earthy smell by producing compunds called geosmins) -produce substances that kill or inhibit the growth of other microbes (used in antibiotics)
51
what do the hyphae of streptomyces produce?
-reproductive spores for dispersal called conidia -NOT endospores -formation process is different -more similar to fungal spores as they have a fuzzy appearance
52
what is an example of the streptomyces genus?
-streptomyces griseus -produces streptomycin (broad spectrum protein synthesis inhibitor that is active against gram negative bacteria)
53
what is the bacterioidetes phylum?
-large and heterogeneous phylum of gram negative bacteria -includes both aerobes and anaerobes -very few unifying characteristics throughout
54
what is an example within the bacteriodetes phylum?
-bacteroides thetaiotaomicron -strict anaerobe -dominant microbe in the human large intestine -produces an enzyme to degrade polysaccharides which greatly increases the variety of plant polymers that can be digested in the human gut
55
if bacteriodes thetaiotaomicron is one of the most dominant in the large intestine, why is it not used instead of e.coli for fecal contamination?
-since it is a strict anaerobe it is much harder to grow in the lab -e.coli is a facultative anaerobe so it is a lot easier to grow and culture
56
what is the chlamydiae phylum?
-phylum of gram negatives that lack peptidoglycan -obligate intracellular pathogens (why they dont suffer without peptidoglycan, dont need the extra protection) -unique life cycle with 2 cell types
57
what are the 2 cell types within the life cycle of the chlamydiae phylum?
-elementary body (do not replicate) -reticulate body (replicate and then convert back to the elementary body to be released after reproduction)
58
what is the standard life cycle of the chlamydiae phylum?
-elementary body attacks the host cell (phagocytosized) -once inside the host cell it converts to the reticulate body -reticulate body reproduces -once reproduction is done they convert back to the elementary bodies and they are released from the host cell
59
what is an example from the chlamydiae phylum?
-chlamydia trachomatis -trachoma (eye infection that causes scarring and blindness)
60
what is the plantomycetes phylum?
-budding and appendaged bacteria -have a protein stalk used for attachment (appendaged aspect) -lack peptidoglycan in the cell wall -some have membrane bound compartments inside the cell (prokaryotes with membrane bound organelles) -causes blurry lines between prokaryotes and eukaryotes
61
what is an example from the plantomycetes phylum?
-gemmata obscuriglobus -has a nucleoid surrounded by a true unit membrane -but still is not the same as a nucleus
62
what are the hyperthermophilic bacteria?
-consist of several deeply branched phyla (close to the LUCA) -suggest that the LUCA may have been a hyperthermophile -main phylum to be discussed is deinoccus-thermus -other phyla (aquificae and thermotogae) grow happily between 85 and 95)
63
what are 2 famous species within the deinococcus-thermus phylum?
-thermus aqauticus -deinococcus radiodurans
64
what are the characteristics of thermus aqauticus?
-a thermophillic chemoorganoheterotroph -is a source of temperature stable enzymes (dont denature at high temps) -taq DNA polymerase can be used for PCR as it can go between different temps with ease (DNA synthesis reactions can be carried out quickly)
65
what are the characteristics of deinococcus radiodurans?
-gram negative but stains gram positive because of having a thick peptidoglycan layer (abnormal) -extremely resistant to radiation (radiation kills by DNA damage) -has a highly effective DNA repair mechanism that allows them to withstand it -form pairs or tetrads -in response to massive DNA damage they can fuse 2 nucleoids from 2 cells to facilitate repair

MBIO1010 (28 decks)

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