Medical Microbiology

RNA VIRUSES: -HIV, Ebola, polio, SARS (all pathogens that are RNA viruses) -RNA polymerase makes both mRNA for proteins and new RNA for viruses -most viruses have an outer protein shell called the CAPSID -occurring in the cytoplasm: -Viral particles get into host cell, and capsid comes off losing its protein shell -it then makes own polymerase to make own RNA and mRNA strands -the new RNA will be the new virus particles RNA POLYMERASE: -T-A-C- beginning sequence- start point (each three base codon is an amino acid) -Sense strand -- being read -Antisense strand – not being read *40 bases (nucleotides) per second* -A-T-T-is a stop codon, which has no amino acid meaning it’s a nonsense codon HIV: -uses reverse transcriptase to make a DNA master for new RNA’s -reverse transcriptase: -makes DNA out of its RNA and uses DNA to make RNA copies that can be used for new RNA’s and new mRNA’s. The DNA is a master copy -left over DNA can go into nucleus, then that cell is permanently infected because DNA is locked in OPERON CONROL: -most proteins produce under operon control -regulates genes by repressors: -proteins that hang onto operator (gateway) to keep it closed -promotor- where polymerase links onto -ahead of polysistronic(one gene follows another) -involves several genes linked without interruption -in order to get proteins they have to derepress-(open “gate”) which is involved in the outside of the cell and lactose a sugar cab tie up the repressor so it can’t bind to operator -feedback kicks out repressor to make amino acids—feedback from metabolic pathways can also derepress -OPERONS: also control multiple virulence production

CHAPERONS: -help fold protein to make it functional -attach to polypeptide chains after translation (also called heat shock proteins) GroEL chaperons: -in prokaryotes only -takes damaged proteins and makes tem the right shape -can recycle damaged proteins during stress DEINOCOCCUS: -have 4-10 copies of genome, which allows for radiation survival -can survive 100 radiations (lethal to humans) -makes a pigment to shield against radiation -RECA proteins: -fragments can be rejoined, to repair broken fragments -originally a method to survive extreme dehydration damage…evolved in hot dry climates millions of years ago BIOLUMENESENSE: -gives off light -enzyme reaction VIBRIOS: -bacteria that gives off light -exists in water because they can stand high salt QUORAM SENSING (LUX GENE): -a unique gene to many bacteria -allows communication by acyl compounds within populations and control of biofilm and toxin formation -has to have a certain number of genes, toxins are under quoram sensing control, signals between microorganisms -lux gene—picks up acyl’s and makes light turn on, lux gene makes acyl, bind to receptor protein **horomones resemble acyl-which can aggravate out bodies systems** TEMPLATES: -ways to make small proteins -10 to 20 amino acids -protein=polypeptide -Bacitracin-12 amino acids involved - doesn’t us MRA uses Template