BIO 326R 1st Edition Lecture 29 Outline of Last Lecture I. Stress Responsea. Generalb. SpecificII. Antimicrobialsa. Traitsb. Historyc. Basic sitesd. Penicilline. Other cell wall inhibitors Outline of Current Lecture I. Antibioticsa. Resistance i. Mechanismsb. EcologyII. Virusesa. Differ from cellsi. Sing and double stranded DNA and RNAii. + and - polarityb. Naked vs. envelopedCurrent LectureAntibiotics Continued- Resistanceo Daptomycin—effective against some gram +- Mechanism of resistanceo Modify or inactivate the antibiotic Like beta- lactam inactivation of beta-lactamaseo Modify the target of the antibiotic by genetic mutationThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Random mutation of component of the antibiotic target so that it no longer can target that componento Restrict access to the target—often by preventing entry into the cytoplasm to prevent targeting transcription Make less permeable—reduce porins for gram – Active efflux of antibiotic out of cytoplasm- Accomplished by membrane proteins (pumps) in cytoplasmic membraneo Pumps usually used to ridding waste but also rid antibiotic- Mutations that increase expression of efflux pumpso Can be a bad thing—broad resistanceo Failure to activate the antibiotic Less common than other mechanisms- Ecologyo Change in microbiota Like clostridium difficile - Not usually a pathogen unless microbiota has been alteredo In typical cases, a reduction in gut flora, often in the hospital settingViruses- Parasites- Mimi virus= ~600 nm (large), 1.1 billion baseso Encodes ~979 proteins- Viruses that kill other viruses- All viruses need a host cell to replicateo Do not have their own replication machineryo Obligate parasites- Differ from cellso No metabolismo No ribosomeso Simple organizationo Different nucleic acids DNA or RNA possible in a single viral genome- dsDNA, ssDNA, ssRNA, or dsRNAo dsDNA and ssDNA still follow the central dogma DNA RNA proteino ssRNA + strand (polarity) viruses= ssRNA genome is an mRNA- Immediately ready to be translated into a protein - strand (polarity) viruses= complementary to mRNA—does not encode protein In both, have a different/unique enzyme that can make RNA from RNA= RNA replicase- + polarity replicase is encoded on the genome—virus enterstranslation of genome (and replicase) replicate RNA genome- - polarity replicase protein enters with the genome- Naked virus (nonenveloped)o Nucleic acid enclosed in capsido Stable against detergents- Enveloped viruso Nucleic acid enclosed in capsid and membraneo Susceptible to detergents Amphiphillic detergent dissolved amphiphillic
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