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87 Cards in this Set
- Front
- Back
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Describe the sucession of bacteria and the peaks that drive the changes in coco fermentation
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yeasts> ethanol peak
latic acid bactiera > lactic acid peak acetic acid bacteria > acetic acid peak, temperature peak spore-forming bacteria |
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what molecule in chocolate has health benefits
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epicatechin
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what is aremsinin
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a drug used to treat multi-drug resistan strains of malaria. It is isolated from the plant Artemisia annua (wormwood). It is only producted when the plant is subjected to stress, E. coli has been engineered to make this drug in a much more reliable fashion
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what is a major CO2 resevoir
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the ocean, the earth's crust
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How is CO2 reduced
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biochemically to carbohydrates during fermentation/ respiration
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which microbes oxidize CO2
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methanogens oxidize CO2 by using it as an electron donor and making CH4`
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Which pathways of the carbon cycle are oxidative
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Respiration- CH2O is oxidized to CO2
Methanotrophy- CH4 is oxidized to CH2O |
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Which pathways of the carbon cycle are reductive
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(anaerobic) Lithotrophy- CO2 is reduced to organic biomass CH2O
Photosynthesis- CO2 is reduced to CH2O Methanogenesis- CO2 is reduced to CH4 |
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what is the reservior for nitrogen
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the atmosphere
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What is the role of nitrogenase
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to fix N2 into NH3 and NH4 (ammonia and ammonium), fertilizer is a way to chemically "fix" nitrogen
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Fixing nitrogen is (reduction. oxidation)
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reductiong, N2 becomes NH3, NH4
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what bacteria oxidize nitrogen from NH3 to NH2OH
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nitrosomonas bacteria
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what is a consequence of excess N2 in the soil
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the excess N2 can end up in water and lead to a high growth rate of microbes. the microbes can use up the oyxgen and lead to hypoxic conditions which restricts the growth of other organisms
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what must be removed druing the waste water treament process
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residual pharmesuticals, pathogens, ecess C,N,P, waste products
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describe preliminary waste water treatment
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removal of large objects by screening
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describe primary waste water treatment
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filtering and settling tank, soaps on top, water in the middle, heavy things like chemicals on the bottom
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describe secondary waste water treatment
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micribial processes, airated tank with aerobic respiration to use carbon, filamentus microbes used so that they settle out of the tank, eukaryotic microbe predators or porkaryotes further control microbes, the sludge settles water water goes on to tertiary treatment, Nitrosomonase and nitrobacter removed nitrogen the goal is to turn the nitrogen into N2 and release it into the atmosphere
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describe tertiary waste water treatment
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chlorination, sluge gets digested via anaerobic fermentaion by methanogens, methane can be burned or turned into fertilizer
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How is phosphorus removed from waste water
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removed from the aerobic tank, cycled back to the anaerobic tank, acumulocater accumulates the phosphorus
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why are soil microbes particularly useful for bioremediation
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they use lignan, polymerized monomerics units, as a large resevoir of biological carbon
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what bacteria is useful in bioremediating uranium, describe the process
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desulfovibrio desulfuricans, usually a sulfer redoxer, can use U6 as an electron acceptor when aetate or molasses is pumped to the ground to serve as an electron donor, the reduced uranium will precipitate so it can't flow into the ground water
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describe the microbes used to clean up oil spills
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they bind to hydrocarons on contact, made of hollow microsperes, N, P, K serve as food sources and they release waste enzymes that break down the hydrocarbon into CO2 and H2O
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describe biofuel production
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microbes break down non human foods, the pathways lead to smaller aromatic compounds that go into the TCA cycle to produce lipids, ethanol, and hydrogen gas, sugars can be turned into ethanol by fermentation, cyanobacteria can make oils as a biofuel source
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describe the "ideal organism" for biofuel production
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possess high substrate use and processing capacities, fast and deregulated pathways of sugar transport, good tolerances to inhibitors and produt, high metabolic fluxes, single fermentation product
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what is biological oxygen demand
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the amount of oxygen needed to support an aquatic community, increasing microbial respiration competes with that of other animals for the limited supply of dissolved oxygen, the higher then concentration of organic substances, the higher the BOD
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define commensal symbioses
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one microbe benefits and the other is unharmmed
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define mutualistic symbiosis
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both parties benefit
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define parasitic or pathogenic symbiosis
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one microbe benefits and the other is harmed
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T/F most host-microbe interactions are harmful
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False, most interactions are commensal or mutualistic
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The rhizobia- legume interaction is an example of what type of symbiosis
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mutualism
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define syntrophy
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an interaction between organisms that combine their metabolic capabilities to catabolize substances that individuals cannot catabolize alone
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what do plants secrete to attrach rhizobia
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flavonoids attrach the bacteria to the roots, the microbe binds loosely to plant lectins and tightly to specific interactions (species specific)
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describe NOD factors
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molecules secreted by rhizobia, hormone like molecules with a chitin backbone,
cause palnt cortical cells to divivde- root hair curling |
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define quorum sensing
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the ability of bacteria to communicate and coordinate behavior via small molecules, applies to both intra and inter species communication, its purpose is to coordinate cetrain behavior based on the local density of bacteria
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what are some things that bacteria use quorum sensing for
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adaptation to availibility of nutrients, defese against other MOs, avoidance of toxic compounds, coordination of virulunce in order to escape the immune response of the host
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Describe how oligopeptides are used in quorum sensing
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used by gram positive bacteria for communication within a species
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Describe how N-acyl Homoserine lactones (AHLs) are used in quorum sensing
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used by gram negative bacteria for communication within a species
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what molecule is used for quorum sensing communication across different species
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Al-2 "auto inducer"
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Give some examples of AHL regulated processes
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Bioluminescence- Vibrio fischeri
Virulence- P. aeruginosa and Agrobacterium tumefaciens antibiotic and exoenzyme production- Erwinina caratovora |
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describe how bioluminescence occurs
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requries oxygen, an unstable flavin molecule is excited and falls back to its resting state releasing light, luciferase reduces long chain aldehyde with electrons consuming oxygen and produing light
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describe the role of the lux operon and quorum sensing in bioluminescence
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when the concentration of AHL exceeds a cetain limit, the transcription of the lux oerpon begins. The AHL helps the LuxR activator bind to the the promoter on the operon and activate transcription. Trascription of the operon results in the expression of LuxA and LuxB which form the luciferase protein
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How is the proper bacteria (V. fischeri) selected into the squid's light organ
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a stickly mucuos binds V. fischeri while cillia beat to keep other microbes out, motility is needed to navigate the duct, in the light organ, macrophages digest other bacteria while the oxidative environment kills others, the V. fischeri binds to a mannose receptor to remain safe. the mircoe then releases a compound that triggers maturation of the light organ through apoptosis
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how can quorum sensing be inhibited by other bacteria
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AHL antagonizing compounds (D. pulchra a red algae eukaryote)
AHL lactonase (Bacillus species) AHL acylase (Ralstonia species) inhibition of autoinducer peptide mediated signaling (S. Aureus) |
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why might a bacteria want to inhibit quorum sensing of another species
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competition for nutrients, modulate pathogenicity
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desribe a biofilm
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structured community of bacteria encolsed in a self produced extracelluar poylmeric matrix adherant to inert or living surfaces
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what do biofilms protect bacteria from
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predators, phages, biocides, antibiotics, immunophagocytes, antibodies
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describe biofilm development
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bacteria in the planktonic (free living) state use flagella and sad genes to lead to cell proliferation and creation of an attached monolayer
type 4 pili, twitching, and sad genes allow for the formation of a microcolony quoram sensing and lasi dependent signaling lead to the formation of a mature biofilm, the mature biofilm and disperse cells in two ways 1 the removal of a segment by physical forces 2. the programmed moblization of planktonic cells |
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describe multispecies biofilms
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coaggregation of genetically distinct bacteria attach via specific molecules, frequently via lectin like adhesions and polysaccardies, it is a very ordered structure with specific interactions
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describe human dental bacterial biofilm (plaque)
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primary colonizers- gram positive rods and cocci
bridge organism- Fusobacterium nucleatum |
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Describe how periodontal pathogens colonize the mouth
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Actionbacillus actinomycetemcmitans and Porphyromonas gingivalis are major periodontal pathogens, they use AI-2 signaling to metabolize carbohydrates and form a mixed species biofilm
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describe how biofilms resist antibiotics
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persister cells are resistant phenotypes, the assum a suspended state which is unaffected by antibiotics, physical barriers such as slime can prevent drug entry and pumps can be upregulated
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how can interferance of quorum sensing be used to treat biofilm infections, what are some advantages of treating infections this way
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breaking down the biofilm can inhibit pathogenicity without the need to kill the cells i.e. if they can't form a film they won't become harmful. by using this technqiue, antibiotic resistance is avoided because the cells are not killed and there is no selective pressure to become resistant
this techniuqe can also be used to help other drugs be more effective and help natural defenses |
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what microbes inhabit the moist areas of the skin
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a large diversity, S. aureus, Corynebacteria species, some gram negative species
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what microbes inhabit the dry areas of skin
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S. epidermidis and P. acnes
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List some bacteria of the oral biofilm
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at least 400 species, Corynebacteria, Lactobacillus, Staphylococcus, Streptococcus, strict anaerobes like Bacteroides
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What are some benefits of normal flora
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colonize surfaces that would otherwise be used by pathogens
stimulate the immune system importnat in the development of gut associated lymphoid tissue synthesize vitamin K and some B vitamins actively antagonzise pathogens |
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List some microbes that inhabit the respiratory tract
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many of the same species as the oral cavity
H. influenaze and M. pneumoniae can cause respiratory disease if body defenses are compromized (opportunistic pathogens) |
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T/F the stomach has lost of microorganisms
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False, the low pH of the stomach inhibits most microbes
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describe probiotics
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live bacteria that have a beneficial effect on the host, elimination of food borne pathogens, help fight off infections
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describe the role of adhesions in pathogenicity
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adhesions allow the pathogens to localize at specific tissue sites, capsule, flagella, and/or pili are adhesions,
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T/F all pathogens must gain entry into tissues to cause disease
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False, pathogens such as B. pertussis and V. cholerase remain on the surface of the respiratory and GI tracts and cause dease by releasing toxins
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Describe some extracellular proteins that pathogens produce to cause damage or avoid host defenses
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leukocidin- protein that is lethal to host phagocytes
hemolysin- dissolves host RBCs limiting oxygen delivery and induces anemia haluronidase- digests hyaloronic acid allowing tissue penetration |
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describe endotoxins
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produced by gram negative bacteria, part of the cells structure (LPS outer membrane), only toxic after cell lysis and release they can increase body temperatue, induce vomiting, diarrhea, hemorrhaging, swelling, shock and death
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describe exotoxins
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produced by gram positive and gram negative bacteria, a toxin that is secreted from the live cell, host responds by producing antibodies
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what is a virulence factor
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required to successfully colonize host, produced by the pathogen and specifically influence host function to allow pathogne to thrive, induce adhesins, exoenzymes, and toxins
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what are the four common steps of all infections
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1. encounter
2. entry 3. establish infection 4. cause damage |
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Describe B. anthracis
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Discovered by Koch in 1877, first microbe shown to cause disease, gram positive endospore forming facultative anaerobe,
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Desce botlinum toxin from Clostridium botulinum
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it is a protease that inhibits membrane fusion and acetylcholine release leading to paralyiss, it can be used for medical and cosmetic applications (botox)
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describe Cholera toxin from Vibrio Cholerae
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AB5 toxin with active subunit ADP-ribosylates the regulatory protein for Adenylate Cyclase
leads to a high concentration of cAMP and an imbalance ofion pumps, leads to severe diarrhea and dehydration |
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what are the three forms of anthrax infection and what do they depend on
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the forms depend on the site of infection
cutaneous anthrax- spores enter through breaks in skin lead to gelatinous edema can spead can cause septicemia GI anthrax- caused by ingestion of spores from undercooked foods, leads to leasions in GI tract Inhalation anthrax- occurs when spores enter the lungs symptoms include malaise, fever, cough and muscle aches (often mistaken for the flu) after 2-3 days abrupt onset of fever and chest pain with rapid progression to systemic infection, rapidly fatal if not Dx early |
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describe the mechanism of anthrax pathogenesis
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polypeptide capsuple- polymer of glutamate gives the microbe a wet mucoid apperance, protects the microbe against phagocytes especially important in early infection, capsule is only made under 5% CO2 atmosphere, bicarbonate is the signal to the microbe that it is in a host, mutants that cannot make the capsule do not cause disease
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describe anthrax toxin and its action
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a zinc dependent metalloprotease, attacks specific kinases in the cell, prevents interaction of signaling pathways and blocks signals to the immune system. Macrophages are the trage and they are forces to secrete shock inducing cytokines which is deadly
edema factor- adenylate cyclase activity leads to cAMP, changes in membrane permeability and efflux of water out, depletes the ATP in neutrophils and macrophages 3 polypeptides LF, EF, and PA form the PA heterodimer and the receptor is endocytosed, |
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How can antrax be treated
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many antibiotics such as penicillin, and ciprofloxacin as a prophylactic, toxins lead to shock and inflammation so the best time for treatment is before the symptoms appear
a vaccine is availble that uses a non-encapsulated strains that produces the protective antigen toxin which stimulates antibody release |
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how does ciprofloxacin work
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it is a member of the fluoroquinolone family and prevents replication by binding GYRASE an enzyme needed to unwind the two strands of parent DNA
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Describe the M. tuberculosis microbe
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large rod, motile, obligate aerobe, grows slowly
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what are the clinical manfestations of M. tuberculosis infection
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there is a wide arrary of outscomes based on the immune response, much of the damage is acutally caused by the immune resonse, the immune system can halt the disease at several stages but it can remain dormant and reestablish itself later
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how is TB treated
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multi drug therapy used to prevent resistance (rifampicin, isoniazid, pyrazinamide, and ethambutol or stremtomycin)
treatment must be continued for 6-9 monts, 95% efficacy pt non compliance a huge problem |
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how does rifampicin work
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inhibits RNA polymerase by bindig to beta subunit
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how does streptomycin work
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it is an aminoglycoside that inhibits translation by binding to the ribosome, it is a natural product of Streptomyces
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what microbe produces a toxin that is used to prevent lepidopteran (gypsy moth) infection of decidious trees
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B. thuringensis, it produces oval shaped spores with a cystal S-endotoxin
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describe B. cereus as a food toxin
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the endotoxin leads to diaherrea and vomiting, hemolysin BL is comprosided of three proteins B, L, an dL2 which lead to pore formation and cell lysis
Cereulide, a 12 amion acid cycylic peptide, is a toxin that leads to vomiting |
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what microbe is most important in cheese fermentation? what does it do?
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lactococcus lactis converts lactose to L-latic acid
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What is a major threat to cheese production (contamination wise)
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bacteriophage
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GIve an example of a non starter lactic acid bacteria and how it can effect cheese production
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L. casei can effect cheese flavor depending on when it is introduced
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What is this molecule and what is its purpose
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This molecule is genistein, a flavoniod. Flavonoids are secreted by plants in order to attrach rhizobia, they bind NodD and initiate the transcrpition pathway for NOD genes. The slight molecular differences among flavonoids lead to the species- species specificty seen in plant- rhizobia interactions
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what is this molecule and what does it do
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This is a NOD factor. Nod factors are secreted by Rhizobia to cause plant cortical cells to divide and lead to root hair curling resulting in nodule formation. The molecule consists of a chitin backbone with an acetylated end and a lipidation end. Nod factors are released after the plants senese flavonoids released from the plant
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What is this molecule and what does it do
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This is the AHL (acyl-homoserine lactone) autoinducer of P. aeruginosa RHl I. The R group after the double bonded oxygen varies depending on species. THis molecule is involved in quorum sensing. In addition to receiving a flavonid signal from plant roots, rhizobia must also sense a quorum using AHL before NOD genes are expressed.
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