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Microbiology 5
| Question | Answer |
|---|---|
| alexander fleming (1881-1955) discovered...and was a... | penicillin...scottish biologist and pharmacologist |
| fleming discovered the..from the... | antibiotic substance penicillin...fungus penicillium for which he shared a nobel prize |
| fleming also discovered the..which is present in... | antibacterial substance lysozyme...human tears and saliva |
| it is estimated that fleming saved....lives bec of his discovery | over 200 million |
| in ..., fleming discovered | 1928...penicillin by accident |
| fleming observed that a plate culture of...had been contaminated by a...and that there were... | staphylococcus....blue-green mold (penicillium)...no colonies of bacteria growing adjacent to the mold |
| efforts to produce large amounts of the mold | failed for the next 10 years |
| thanks to the combined efforts of...penicillin was available in quantity to treat... | flory and chain....allied soldiers wounded on d-day and thereafter |
| fleming, flory and chain won the | nobel prize for medicine in 1945 |
| antiobiotic means | against loiving organisms (drug) |
| antimicrobial means | against microbe |
| narrow spectrum means | effective against only a limited range of organisms |
| ex of narrow spectrum is...bec it is effective against mostly... | penicillin...G+ bacteria (bec target is peptidoglycan and G-'s outer membrane prevents penicillin from getting to PG layer) |
| broad spectrum means | an antibiotic with activity against a wide range of organisms |
| ex of broad spectrum | amoxicillin is effective againstboth G+/- bacteria |
| bactericidal (cidal) means a drug that | completely destroys/kills bacteria |
| bactericidal is best for | immunosuppressed patients |
| ex of bactericidal would be | cell wall antibiotics like penicillin |
| penicllin works by...to... | irreversibly binding...active site or enzymes that link PG molecules |
| PG subunits include | nag (no peptide linkage), nam (peptide linkage) |
| alternating subunites form | PG layer |
| as the bacterical cell grows, penicillin | prevents the formation of the nam-nam peptide linkage during PG synthesis |
| bacteriostatic (static) refers to drugs | that stop cell growth |
| ex of bacteriostatic...which is a drug that ibinds to...and stops...which then stops.. | erythromycin...subunits of bacterial ribosomes...bacterial protein synthesis ..growth of bacteria w/o destroying them |
| antibiotics are often | derived from microbial species |
| semisynthetic antibiotics are molecules derived from a... | biological source and manipulated in the lab to improve characteristics |
| penicillium chrysogenum's antimicrobial is | penicillin |
| penicillium griseofulvum's antimicrobial is | griseofulvin |
| cephalosporiu's antimicrobial is | cephalothin |
| amycolatopsis orientalis' antimicrobial is | vancomycin |
| amycolatopsis rifamycinica's antimicrobial is | rifampin |
| bacillus licheniformis's antimicrobial is | bacitracin |
| bacillus polymyxa's antimicrobial is | polymixin |
| micromonospora purpurea's antimicrobial is | gentamicin |
| pseudomonas fluorescens antimicrobial is | mupirocin |
| steptomyces griseus's antimicrobial is | streptomycin |
| strepcomyces fradiae's antimicrobial is | meomycin |
| streptomyces aureafaciens' antimicrobial is | tetracycline |
| streptomyces venequelae's antimicrobial is | chloramphenical |
| streptomyces arythraeus' antimicrobial is | erthromycin |
| streptomyces nodosus' antimicrobial is | amphatericin B |
| strepcomyces avermitilis antimicrobial is | ivermectin |
| selective toxicity is when something is | toxic to one thing but not another |
| a good antibacterial drug should be | highly toxic to bacteria but non-toxic or very little toxicity to humans |
| unique target is the basis for | selective toxicity |
| the unique target is the site in a...that is...and it is what the drug needs to... | pathogen...infecting the patient...work on specifically and is not present in the patient |
| exampo=le of unique target would be | penicillin targeting PG which is present in bacteria only |
| unique targets provide a reason we need to | compare pros (bacteria) and eukaryotes (humans) in detail |
| prophylaxis is a | preventative method |
| prophylaxis example would be if a patient has a history of...you would treat...with... | rheumatic fever...prophylactically...antibiotics before a dental or surgical procedure |
| cell wall synthesis inhibitors are....and their unique target is the... | bactericidal...cell wall |
| cell wall synthesis inhibitors include | beta lactams, vancomycin and bacitracin |
| beta lactams form the basis of | things that synthesize more peptidoglycan |
| beta lactams include | penicillins and cephalosporins |
| dna synthesis inhibitors are...and they target the... | bactericidal...dna polymerase (replication) |
| dna synthesis inhibitors include | quinolones and metronidazoles |
| rna plymerase inhibitors are...and they target... | bactericidal...rna polymerase (transcription) |
| rna polymerase inhibitors include | rifampin |
| plasma membrane inhibitors are...and they target... | bactericidal...cytoplasmic membranes |
| plasma membrane inhibitors include..which do what... | polymyxins...insert peptides that disrupt the membrane |
| protein synthesis inhibitors are...and their target is... | bacteristatic ...70s ribosomes (translation) |
| protein synthesis inhibitors include | erythromycin, chloramphenicol and tetracycline |
| antimetabolites are...and their target is... | bacteriostatic...metabolites needed for growth |
| antimetabolitesinclude | folic acid syhnthesis inhibitors |
| folic acid synthesis inhibitors include | sulfonamides |
| side effects of antibiotics include | allergies and organ toxicity |
| allergies to penicillin include | hypersensitivity (anaphylaxis) which may lead to shock and death |
| all drugs can cause | allergies (have to check w/ patient) |
| organ toxicity happens in side effect to | vancomycin, chloramphenicol, bacitracin and tetracycline |
| vancomycin can be | neurotoxic or nephrotoxic |
| chloramphenicol can ..by... | suppress bone marrow function...depressing immune system |
| bacitracin can be...and it is only used as a... | nephrotoxic...topical agent |
| tetracyclin complexes with...and causes... | calcium...abnormalities in bone and teeth |
| you should avoid giving..to... | tetracyclin...children and pregnant women |
| the human commensal flora is a term given to all | the natural bacteria that live on and in a healthy person |
| there are about..living in the human...which is about... | 10^14 bacteria..gut...10x as many human cells in the entire body |
| many of these bacteria have...relationships with the host | mutualistic or potentially pathogenic |
| the major areas of colonization are the | skin, oral cavity, upper resp tract, lower GI and the urogenital tract |
| populations in the...can reach... | small intestine...10^11 cells per ml. of feces |
| harmful commensals can cause | opportunistic infections (e. coli causes UTIs) |
| unique targets in fungi includ | ergosterol |
| fungi are more closely | related to humans than bacteria |
| ergosterol is only in | fungal plasma membranes and belongs to the steroid fam |
| the...inhibit the synthesis of... | azole antifungal agents...ergosterol |
| azole antifungal agents result in the | accumulation of toxic sterols in the fungal plasma membrane leading to te cell death |
| mechanisms of drug resistance include | inactivation, decreased uptake, pump, overproduction of the target and metabolic bypass |
| inactivation is when the...for example... | drug is destroyed....penicillin resistant bacteria produce B=lactamase, destroying the drug's target-binding site |
| decreased uptake happens when the...so that the drug can no longer... | bacterium changes...get into the bacterium to act |
| pumps do what | pump the drug right back out |
| ex of pump | tetracycline resistant bacteria pump out the drug |
| overproduction of the target happens when the...to a specific molecule, bacteri amkes huge... | antibiotic binds...numbers of those molecules so they are not all inhibited from working |
| metabolic bypassmakes the | target redundant |
| plasmids are | circular dna outside of the chromosome in bacteria |
| A. Griffith was the fifrst to | demonstrate genetic transfer 1920 |
| how do microbial resistances arise | genetic transfer |
| ex of genetic trasnfer | mice with S strain w/ capsule died, ones without capsule (glycocalyx) lived, mixed two strains (S&R) and it killed mice bec even dead dna from S joined with R |
| the glycocalyx serves as a | virulence factor |
| important observations from griffith's experiment: bacteria can | exchange genetic material |
| important observations from griffith's experiment: avery suggested the molecule responsible for | transformation (transforming principle) was DNA |
| important observations from griffith's experiment: the transforming molecule was not destroyed by...but was destroyed by... | protease or rnase...dnase so it was DNA |
| the work of hershey and chase provided the final | proof that DNA, not protein, was the genetic material which is the component of heredity |
| DNA is sufficiently ...for.. | complex..genetic code since 3 contiguous bases in the DNA strand encode one amino acid |
| mechanisms of drug resistance also include | mutations |
| mutations are the | change in the genetic material (DNA) |
| mutations can either be | spontaneous or induced |
| spontaneous mutations are | extremely rare events which occurs as a result of natural processes in cells |
| ex of spontaneous mutations | mistakes in DNA replication |
| induced mutations occur...as a result of... | more frequently...interaction of DNA with a mutagen |
| mutagens are an | outside agent that induces mutation (evolutionary principle) |
| mutagens are...that change the... | natural or human-made (physical or chemical) agents...genome (DNA) or an organism |
| mutagens increase the | frequency of mutations above the natural spontaneous rates |
| examples of mutagens are | UV light (sun screan), pesticides (eat organic), pollutants such as cigs, food additives (read labels) |
| do mutagens select for mutants?...e.g.... | no...antibiotic in the patient selects for cells that are resistant |
| antibiotics do not..they only... | induce mutation..provide selective pressure for the mutant bacteria to grow |
| mechanisms of gene transfer in bacteria | transformation (naked DNA), conjugation (plasmid DNA) transduction (bacteriophages) |
| transformation is...but since theres... | rare...so many bacteria in a colony, it happens often |
| transformation is the procesas by which...take up...and... | bacterial cells...naked DNa molecules...incorporate it to their own DNA |
| example of transformation | Griffith's experiment w/ s. pneumoniae production of capsule |
| efficiency of gene transfer in case of transformation is...since bacteria have to be the... | low...same or very close relative to each other |
| transformation occurs as...combine with... | dna fragments....recipient cell w/ chromosomal DNA |
| first step of transformation happens when the recipient cell | takes up donor dNA |
| second step of transformation, ... occurs between.... | recombination...donor DNA and recip DNA |
| conjugation can happen between...as long as... | two dif species...there is the same surface protein present |
| conjugation is an | active process |
| conjugation is also called...and works best with... | nonconventional bacterial sex...g- |
| in conjugation, the...has an...coding for a... | f+ male...F+ plasmid...sex pilus and can serve as a genetic donor |
| the sex pilus....and then... | adheres to an F- female (recip)...one strand of the f+ plasmid breaks |
| the sex pilus then...and a...between... | retracts...bridge is formed...two bacteria |
| once the bridge is formed between the two bacteria, one | strand of the f+ plasmid enters the recip bacterium |
| in conjugation, both bacteria then make a...and both are now... | complementary strand of the F+ plasmid...f+, capable of producing a sex pilus |
| conjugation is the... | most efficient mechanism of genetic exchange amongst bacteria |
| in conjugation, the F+ can cause the F- to be | antibiotic resistant also |
| transduction happens via a...which is a... | bacteriophage...virus that attacts bacteria |
| transduction begins with a.. | lytic bacteriophage adhering to a susceptible bacterium |
| in trandsuction, after the lytic bact. adheres to a bacterium, the bacteriophage....and... | genome enters the bacterium...directs the bacteriums metabolic machinery to manufacture bacteriphage components and enzymes |
| occasionaly during...a... | maturation (transduction)...bacteriophage head or capsid assembles around a fragment of donor bacterium's nucleoid or around a plasmid instead of a phage genome by mistake |
| step four of transduction | bacteriphages are released |
| step 5 of transduction involves the bacteriphage that is....to... | carrying the donor bacteriums DNA...adhere to a recipient bacterium |
| the bacteriophage then (step 6 of transduction) | inserts the donor bacteriums DNA into the recipient bacterium |
| the donor bacterium's dna is then | exchanged for some of the recipient's DNA (step 7) |
| what can mix in the lysogenic phase | viral DNa and bacterial dna |
| plasmids are a problem in the..bec they are... | clinic...resistant |
| plasmids are | small, circular molecules of DNA that are seperate from the bacterial chromosome |
| the size of a plasmid ranges from | 3-20% of the size of the bacterial chromosome |
| plasmids ofte3n carry | genes that affect the ability of bacteria to respond to environmental challenges |
| plasmid genes determine....including... | a wide variety of bacterial properties ...pilus formation, resistance to antibiotics, ability to produce toxins (virulence factors) |
| plasmids are often used as | vectors in recombinant DNA tech |
| r factors are..that carry... | plasmids...r (resistant) genes for antibiotics and gives the bacterium the ability to resist many antibiotics |
| recombinant protein examples include | human insulin, vaccines, antibiotics, hormones,enzymes and spider silk |
| transgenics is the process of taking... | genes from one species to the next |
| transgenic things can include...like.. | microbes, plants or animals...herbicide resistant cereal crops, animals producing foreign proteins |
| knock out or knock in mice involve the....in order to study... | removal or replacement of a gene with a mutant form from/to a mouse...effect of gene silencing, or to study the effects |
| knock out and knock in methods are useful to study | new therapies for human inborn errors of metabolism |
| a transgenic animal or plant is a | genetically modified organismt that carries a foreign gene from another species that has been deliberately inserted into its genome by techniques of genetic engineering |
| the foreing gene in transgenic animals/plants is constructed using | recombinant DNA methodology |
| in animals for transgenesis, a...is added to a... | gene...fertilized egg cell, planted in a uterus, and the animal grows that expresses the new gene |
| animals can then | pass the gene on to its progeny |
| cloing an animal involves first taking a ...and... | donor egg...removing the nucleus |
| once the nucleus is removed, you | fuse a diff animal's cell and the enucleated egg with electricity |
| the fused egg w/ cell forms an..and then you just have to... | embryo...implant the embryo |
| DNA sequencing is the process of | determining the exact order of the 3 billion base pairs that make up the dna of the 24 diff human chromosomes |
| the worlwide scientific project began in...and was completed in... | 1990-2003 |
| achieving this goal has helped reveal the estimaed...human genes w/i our dNA as well as the... | 20,000-25,000...regions controlling them |
| the ultimate goal of genome research is to find...and to develop tools for... | all the genes in the DNA sequence...using this info in the study of human bio and medicine |
| the treatment of..is our biggest challenge | staphylococcus aureus |
| staphylococcus aureus is a | major human pathogen causing a variety of infections - some life threatening |
| an increasing number of...that are... | patients are being seen w/ skin infections caused by staph aureus...resistant to many antibiotics |
| ...was introduced in...to fight staphy aureus | penicillin g...1942 |
| in the 1950s a ...bug strain devestated hospital patients world wide | penicillin-resistant staph |
| methicillin was made in...and is a... | 1960s...penecillin derivative not affected by beta lactams |
| staph aureus became resistant to ...in... | methicillin...1970s (MRSA) |
| lastly, ...was found in...and involved... | vancomycin...1970s...visa 1997 and vrsa 2000 |
| today,..is the most common drug resistant bug in... | mrsa...north america, europe, north africa, middle east, and east asia |
Created by:
handrzej
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