Organism of The Week Microbiology

myxococcus xanthus

• soil bacterium; gliding motion + mobile biofilm

• mistaken for eukaryote due to other multicellular behavior

• eats amino acids and other bacteria

• multicellular fruiting bodies, sporulous

• makes antibiotics + anticancer drugs

streptococcus pneumoniae

• gram positive dipolccocus

• infects lungs; responsible for the flu deaths as secondary infection

• natural transformation with com system

• makes 90 different capsules to invade immune system

• capsules will mimic host sugars

Yersinia pestis

• the bacterium that causes black plague that killed 30% of the European population

• vectors are rodents and fleas

• virulence factors encoded on plasmids; injects toxins directly

  • the plasmid HPI responsible for biofilm formation is what causes the fleas’ digestive tract to be blocked which makes them bite more humans and when they are unable to feast they spit pathogen into the human

  • plasmid pPCP1 - encodes for protease

  • plasmid pMTI - encodes for pili

  • plasmid pCO1 - encodes for toxins and type III secretion which allows for toxins to be directly injected into the host cells and minimizes the ability of the toxins to be revealed

Streptomyces coelicolor

• resembles eukaryotic fungus

• gram positive soil bacterium; large linear chromosome

• hyphal growth + cell division is rare

• developmental cycle, sporulation, polyketide antibiotics

• 75% of antibiotics come from strep; species unique + multiple antibiotics

• aerial spores grow into air and forms chains of spores

• during starvation it will secrete antibiotics and hydrophobin