chapter 7 pt 2 Flashcards
human bacteria
symbiotic
-some can become opportunistic pathogens and cause infection
biofilm
surface microorgamisms enclosed in an extracellular matrix
-on most natural environments on earth
quorum sensing
bacterial communication with chemical messages than initiate a repsonse as a function of population density
-function as a group to accomplish tasks too big for one cell
-release toxin, digest food, flourescence
pseudomonas
-small gram negative rods with single polar flagellum
-free living in soil, sea, plants an d animals (biofilms)
-contaminate homes and hospitals
-decomposers
-aerobic respiration but dont ferment carbohydrates (non fermenters)
-produce oxidase and catalase, some make water soluble pigments
-true pathogens of plants
can some psuedomonas grow anaerobically?
yes but only if given growth factors
pseudomonas aeruginosa
soil and water
-intestinal resident in some people
-resist soap, dyes, quaternary ammonium disinfectant, drugs and drying
-contaminate ventilators, iv solutions, anesthesia equipment, contact lenses
-grape odor, green blue pigment (pyocyanin)
-multidrug resistance
-opportunistic nosocomial pathogen (attacks unhealthy) (burns, cancer, CF)
-pneumonia, uti, abscesses, corneal disease otitis externa (minor ear infection)
-meningitis, endocarditis, bronchopneumonia, bone and joint infection
-no tissue, cant infect
-eye drop outbreak
how do psuedomonas talk
autoinducer molecules
-inhibit them to shut down biofilm and toxin secretion
-can potentially put the inhibiting agent on clothing, medical supplies etc
microbial growth
-grows at cellular level which increases size
-grows at population level
binary fission
-how cell divides (splits in half)
-parent cell enlargers, duplicates chromosome, forms septum dividing the cell into 2 daughter cells
generation/ doubling time
time necessary for fission cycle
-each new cycle increases population by factor of 2 (exponential growth)
generation time
minutes or days
equation for population size
nf= (ni)2^n
nf
total number of cells in the population
ni
starting number of cells
exponent N
number of generations