Biology M200 1st Edition Lecture 10 Outline of Last Lecture I. Controlling microbiological growth in the environmentOutline of Current Lecture II. Controlling microbiological growth in the bodyIII. AntibioticsCurrent LectureHistory of antibiotics- Alexander Flemingo Worked with bacteriao Fungus called Penicillium secreted something that killed nearby bacteria.- Gerhard Domagko Discovered sulfonamides (first large-scale use of an antibiotic)- Selman Waksmano Discovered many species of soil-dwelling bacteria produced antibiotics.Antibiotics and Selective Toxicity- To be useful to humans, an antibiotic must have SELECTIVE TOXICITY.- To be selective, the antibiotic must target specialized function in a microorganism.Selective Toxicity- Antibacterial antibiotics are the largest and most diverse group of antimicrobial agents.- Even fewer antiviral agents- why? Think about how viruses infect.Inhibition of Cell wall synthesis- Beta-Lactam antibiotics prevent the NAM in peptidoglycan from forming cross-linkers.Other Inhibitors of cell wall synthesis- Bacitracin: blocks transport of NAG and NAM from cytoplasm out to the cell wall. - Vancomycin: interferes with the formation of NAM to NAM bonds in Gram-positive bacteria.These 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.Inhibition of protein synthesis- Prokaryotic ribosomes are 70S- Eukaryotic ribosomes are 80S- Drugs can selectively target translation in 70S ribosome.Antibiotics:- Tetracyclineo Blocks the tRNA binding siteo Amino acids can no longer be added.- Streptomycino Changes the shape of 70S ribosomeso mRNA is misread- Chloramphenicolo Blocks peptide bond formation- Lincomycino Prevents movement of the ribosome.o Translation stops.Disruption of cell membranes:- Gramicidin- disrupts cytoplasmic membranes of Gram-positive bacteria.o Also eukaryotic cells.o Can only be used on skin.- Polymyxin- disrupts cytoplasmic membranes of Gram-negative bacteria.o Toxic: Kidney and nerve damage.Targeting metabolism- Humans get folic acid in their diet. - Bacteria must make their own folic