BIMM 120 CH 1

1-2um

everywhere

T. namibiensis

bacteria, archaea, and eukarya

Bacteria and archaea

collection of DNA sequences within an environment

2 million

1000bp/gene

bacteria on teeth

non-living

False

litotrophs

• - first compound light microscope
• - coined the term "cell"

- first to observe single-celled microbes

• - microbial basis of fermentation
• - swan-neck flask

clone of cells derived from same parent cell

• 1. microbe is always present in diseased host and absent in healthy individuals
• 2. microbe can be grown in pure culture and characterized
• 3. introduction of microbe into healthy host causes the original disease
• 4. same microbe is re-isolated from new host

antiseptic prevents bacterial growth whereas antibiotic kills and stops bacterial growth

completely pathogen free

penicillin; Fleming

Tobacco Mosaic disease

• discovered litotrophs using enrichment cultures
• developed Winogradsky column

Fix nitrogen to ammonium

microbes living symbiotically inside larger organism

induce the roots of legumes to form special nodules to facilitate bacterial nitrogen fixation

• light microscopes too low resolution
• microbial species are hard to define

cyanobacteria

proteobacteria

discovered archaea growing in hot springs that produced methane

• electron microscope
• ultracentrifuge