19.7 BACTERIAL DIVERSITY

Bacteria serve as decomposers, cycle nutrients, and form partnership with many other species.

Heat-Loving Bacteria- Thermus Aquaticus, was discovered in a volcanic spring in Yellowstone National Park.

- Biochemist, Kary Mullis isolated a heat stable DNA polymerase from T. Aquaticus and put the enzyme to work in the first PCR reactions. He won a Nobel Prize for inventing this process which is now widely used in biotechnology.

19.7 BACTERIAL DIVERSITY

Oxygen-Producing Cyanobacteria Cyanobacteria – releases fee oxygen by a noncyclic pathway, as plants do.

- Some cyanobacteria partner with fungi and form lichens and some live on the surface of soil but most are aquatic.

- Other aquatic cyanobacteria carry out the ecologically important task of Nitrogen Fixation: Incorporation of nitrogen gas to ammonia.

19.7 BACTERIAL DIVERSITY

Highly Diverse Proteobacteria

Proteobacteria – the most diverse bacterial lineage, also includes some nitrogen fixers.

- are a major group (phylum) of gram-negative bacteria.

-They include a wide variety of pathogens, such as Escherichia, Salmonella, Vibrio, Helicobacter, and Yersinia, and many other notable genera. Others are free-living (nonparasitic), and include many of the bacteria responsible for nitroge fixation.

Normal Flora – normally harmless or beneficial microorganisms that typically live in or on a body.

19.7 BACTERIAL DIVERSITY

The Thick-Walled Gram PositivesGram Staining- process used to prepare bacterial cells for microscopy, and to distinguish groups based on a cell wall structure

19.7 BACTERIAL DIVERSITY

[The staining process is allowed to be carried out for 2-3 minutes. The smear is washed again, heat dried and examined microscopically.]

19.7 BACTERIAL DIVERSITYGram Positive Bacteria – are lineage characterized by thick cell walls that are tinted purple when prepared for microscopy by Gram staining.

Gram Negative Bacteria – thinner-walled bacteria such as cyanobacteria and proteobacteria are stained by pink.

Endospore – it can survive heating, freezing, radiation and disinfectants. - resistant resting stage of some soil bacteria.

Clostridium and Bacillus are one of the gram positive soil …bacteria that can form an endospore.

Spring-Shaped Spirochetes

Spirochetes – is a bacteria that resemble a stretched-out spring.

A pathogenic spirochete causes the sexually ..transmitted disease syphilis.

19.7 BACTERIAL DIVERSITY

Parasitic Chlamydias

Chlamydias are tiny cocci. - They can only live and replicate in eukaryotic cells.

Chlamydia infection is the most commonly sexually transmitted bacterial disease in the United States.

19.7 BACTERIAL DIVERSITY