Lecture 7: Prokaryotic diversity Flashcards

Question

Provide an example of a member part of the mycobacteria

Answer 1

Mycobacterium tuberculosis • SLOW growing (~ 24 hr/gen) - can get a test (swab of sputum) but won't see growth for a long period of time on a petri dish - but would do genetic analysis, chest X-ray, manto test etc., in meantime in order to make a (+) diagnosis • Colonies can take weeks to form on agar medium (for conclusive (+) diagnosis) • Cause of tuberculosis – slow, fatal respiratory disease * in active cases vs. latent infection (substantial amount of ppl can become active cases)

Answer 2

• Genus of filamentous (long and thin) Gram positives • Form branching hyphae and mycelia - sounds like gungi, extracellular digestion and absorption • Hyphae produce reproductive spores for dispersal – conidia • DO NOT PRODUCE endospores - OBLIGATE AEROBES Live in well aerated soils;in well mixed soils, O2 at top is mixed into layers below • Give soil its earthy smell: geosmins • Also produce substances that kill or inhibit the growth of other microbes - antibiotics; organism tries to kill off competitors

Answer 3

• Produces streptomycin: BROAD spectrum protein synthesis INHIBITOR active AGAINST Gram NEGATIVE bacteria - widely used antibiotic - not just targeting 1 partic. species (ex: Mycobacterium tuberculus only targets 1 partic. species (v. narrow spectrum) - narrow spectrum in the sense that its active against gram - bacteria NOT gram +

Answer 4

a) Streptomyces griseus CORRECT - an ex of obligate aerobes b) a member of the bacteriodetes phylum such as Bacteriodes spp. - obligate ANAEROBES - tube would have it down at bottom (far from O2) c) using fermentation to produce ATP - organism in q is engaging with aerobic respiration - using O2 & cellular respiration - NOT fermentation b/c it would've been far away from O2 & this is close to O2 so means it must be using O2 d) cannot produce enzymes to remove ROS - can tolerate O2, therefore means you must be able to deal with the toxic forms that accumulate - so would need enzymes (only obligate anaerobes or microaerophiles don't produce them - steer clear of O2)

Answer 5

• Large, heterogeneous phylum of Gram NEGATIVE bacteria • Aerobes and anaerobes - diversity with respect to O2 utilization • FEW unifying characteristics - genetically makes sense to put them here, but aside from that, diff. to group based on physical features or phenotypes

Answer 6

Bacteroides (genus) thetaiotaomicron • STRICT ANAEROBE - poisoned by presence of O2 (can't tolerate it) • NUMERICALLY DOMINANT microbe in the human large intestine - even if you got a lot of species diversity (lot of diff. organisms present within large intestine that collectively create your community within environment) - these organisms will still be most abundant numerically • PRODUCES ENZYMES to DEGRADE POLYSACCHARIDES, greatly increasing the variety of plant polymers that can be digested in the human gut - expansion of what is able to be digested

Answer 7

• PRODUCES ENZYMES to DEGRADE POLYSACCHARIDES; we haven't digested it, it went straight thru small intestine which is location for absorption and digestion but in this case we didn't do anything with it but this organism has enzymes allowing for it to be digested greatly increasing the variety of plant polymers that can be digested in the human gut - expansion of what is able to be digested * if it wasn't present we wouldn't be able to digest it *we aren't specialized for absorption in LI that means simple sugars produced by this will only be used to sustain local microbial growth, whatever organism doesn't take if its hydrophobic and small it can cross wall of LI and into blood stream

Answer 8

• Gram negative cell wall type, but lack peptidoglycan • Obligate intracellular parasites; obligation to live inside and parasit= +/- similar to viruses in this way, small like them - cant be grown in the lab * most relevant STI can casue PID

Answer 9

• Unique life-cycle with two types of cells: 1. Elementary body • Small dense cell, resists drying • Allows infection of new host cells * INFECTIOUS FORM naive cell= uninfected 2. Reticulate body - large vegetative cell (metabolically active, making proteins) - multiplying in host cell - not infective

Answer 10

Example: Chlamydia trachomatis • Trachoma: infection of the eye • Causes scarring and blindness in certain places in the world this is more common among children bc of closeness and can be spread from person to person bc of close interactions -WOMEN will have higher chance of getting this bc mother is in contact with kids more the infection can be gotten and then cleared so isnt a problem but problem is with recurrent infection which leads to scar tissue formation * eyelashes rub on surface of eye everytime you blink bad bc it can scar the surface and make it difficult to see

Answer 11

organism is living inside of the cell; nto free living so antibiotic needs to have good tissue penetration

Answer 12

STI travel in groups just based on mode of spread ; if person has one they could have others want to give treatment that'll have good coverage against more than 1

Answer 13

Neither Gram + or -; protein cell wall similar to archea - No PD - Protein stalk for attachment - Appendaged bacteria and Budding bacteria - membrane bound compartments Example: Gemmata obscuriglobus • Nuceoid is surrounded by a true unit membrane

Answer 14

Impressive morphological diversity, generally larger than other bacteria: pleomorphic • Unicellular, filamentous, or branching filamentous * Some form heterocysts * Specialized nitrogen fixing cells ( anoxic environment; low o2 environment) bc poisined by O2 arry out oxygenic photosynthesis • Harvest energy from light, and produce oxygen • All are autotrophs • Fix CO2 to build cell material- Calvin cycle • Like chloroplasts they carry out photosynthesis in specialized membranes called thylakoids * Unlike chloroplasts they have cell walls * Contain peptidoglycan * Gram negative cell wall type

Answer 15

- Most abundant and encountered * contain medically relevant bacteria - diverse metabolic styles - Facultative; can switch metabolic styles depending on what is present or not Alpha Gamma Beta; well studied Delta-, Epsilon- are smaller classes but with a broad range of phenotypes • Zetaproteobacteria has barely been studied with only one known species: Mariprofundus ferrooxydans

Answer 16

includes path/ non pathogens ex; non path ``` Rhizobium leguminosarum • Forms root nodules on legume plants • Symbiotic relationship • Bacterium fixes nitrogen into a bioavailable form n2--> 2 NH3 • Plant provides nutrients and a home for the bacteria ``` ``` pathogen ex; Rickettsia rickettsii • Obligate intracellular pathogen • Carried by insects and transmitted by insect bites; vector based transmission • Causes Rocky Mountain spotted fever • Phylogenetically Rickettsia is the closest relative to the eukaryotic mitochondrion ```

Answer 17

Metabolically diverse; shows that we shouldn't use functional diversity • Some are pathogens and some are non- pathogens • Examples: • Neisseria mucosa • Non-pathogenic commensal of the human body: lives on mucous membranes - lives on mucosal sites and has modes of attachment so it doesn't get flushed - microbial antagonism and competitive exclusion • Neisseria gonorrhoeae • Pathogenic: causes gonorrhea

Answer 18

Metabolically and ecologically diverse • Many grow well in the lab and have become important research models • Examples: • Escherichia coli • Gram negative, rod shaped, facultative aerobes • Motile by means of peritrichous flagella • Ferments lactose to a mixture of acids and alcohols • Resident of the large intestine of warm-blooded animals • Serves as an important indicator of fecal contamination Pseudomonas aeruginosa • Gram negative, rod shaped, motile by means of polar flagella • Does not ferment sugars • Naturally resistant to many antibiotics and disinfectantsl; grows in contact lens solutions • Opportunistic pathogen – causes infections in immunocompromised patients * coward- looking for organisms that cant fight back • Ex) Respiratory tract infections in cystic fibrosis patients

Answer 19

causes infections in immunocompromised | patients