Lecture 3, 9/5/07

• • CJD – no nucleic acids
• How do they reproduce if they are just protein.
• Mold have spores, yeast have buds.
• Cynobacteria are filamentous

• reasons to take micro
• ubiquitous distribution – widest distribution of any living organisms
• ideal experimental subjects
• they grow so rapidly
• a new generation of e. coli comes around every 20 min. we have more information on this one cell than any other cell in the world
• bacillus subtilis* has the second most information
• we have about a 20 year generation
• cause variety of diseases
• study of microorganisms began to understand the major epidemics such as: smallpox, polio, TB*, the plague, diptheria
• Top Disease killers Today:
• diahhrea caused by cholera or e. coli and many protozoans
• pnemonia. Pnemonia organisms: mycoplasma, streptococcus, etc
• TB – kills 3 million/yr
• malaria is a protozoan
• Hep B caused by a virus called HBV. There is a link between HBV and and primary hepatinoma liver cancer
• Measles – kills 1.5 million/yr
• Tetnus (we don’t see it due to vaccinations) - clostridium tetna* – lockjaw. Can’t get your nerves to relax. There was a horse with this and its tail was straight out
• purtussis (this is still seen in those who do not get vaccinated – whooping cough
• HIV
• Dysyntari - shigella dysenteriae – looks a lot like e. coli – tough organism
• Vacilary dysyntary
• In civil war more people died from dysenteriae than anything else
• Causes severe diarrhea
• you either have infectious disease or rectal cancer if you have blood in your poop

• • CYCLE OF LIFE – this world might last only a week without bacteria. Bacteria are big in going from inorganic to organic
• plants – need inorganic material (autotrophs)→ animals – eat organic nutrients (heterotrophs) → microorganisms (autotrophs and heterotrophs) →plants → animals (etc)
• microorganisms take things from organic to inorganic allowing plants to use them

• • Genetic Engineering
• e. coli – read the ecoli article
• (this process is a little bit confusing to me but I wrote it down as best I could) e. coli has something called a plasmid. This is what you use to make copies. Cut the plasmid with restriction enzymes. Cut the DNA of the host too. Then you put back together the plasmid and a gene from the eukaryotic cell – tied in by DNA ligase. Once you have this recombinant DNA and e. coli’s plasmid (chimera) then you put it back into another e.coli by a process called transformation. Once it is there it is called the expression host/ expression vector. You can then go two ways: make genes or more e. coli (gene cloning). This e. coli then can pump off different stuff such as insulin. This is called end product cloning
• for all this to occur you need
  

• a host cell
  
• a plasmid (from e. coli)
• foreign DNA purified by electrophoresis
• restriction endonuclease to cut the DNA
• and something to tie it together DNA ligase

• • Unique biochemical aspects of some prokaryotic cells
• nitrogen fixation
• we can’t use inorganic nitrogen. The microorganism change it to organic so we can use it. N2 → NH3 → Organic nitrogen
• NIF gene allows these certain organisms to do this. The organisms are: Rhizobium. The Rhizobium are part of a symbiotic relationship with legumes (alfalfa, soybeans). Some genetic engineering will allow plants to create their own nitrogen
• Free living – non-symbiotic nitrogen fixers – Azotobacter choococcum
• extreme thermophily – grow at high temperatures in boiling hot springs and volcanic vents in the oceans.
• chemoautotrophy – they get their energy from the oxidation of inorganic substances.
• We get our energy from oxidized organic substances, we are chemoheterotrophs
• If an organism has “nitro” in front of it then it is probably a chemoautotroph.
• Obligate anaerobiosis – organisms that only grow without air (e. coli and yeast can go either way)
• Grow without air – that is the only way they can grow. This is the clostridial group.
• Ex. botulism, tetanus, gas gang green or turkey day food poisoning.
• Clostridium difficile – causes AAPMC – antibiotic associated pseudo membranous colitus. We all have it in our intestines (small numbers). When you take a lot of antibiotics you kill the good guys and these guys take over
• Bacteroides fragilis – if this gets into your peritoneum you will be very sick

• • HISTORY
• Fracastoro (monk)
• Infectious disease
• disease was spread from person to person
• Kircher (monk)
• Worms (invisible) can be in bad meat and bad milk and poop
• Hooke
• First one to see molds