BIOL/CSES 4684

OSCILLATORIA

SOIL MICROBIOLOGY

This webpage was created by Karen Stewart

1. IDENTIFYING CHARACTERISTICS

Oxygenic Phototrophic bacteria, but can perform Anoxygenic Photosynthesis.
Straight unbranched trichome.
Exclusively vegetative cells.
Contains gas vacuoles.
Contains Chlorophyll a.
Cells stain Gram negative.
Species are motile by gliding.
No unusual structures are formed.
Produces Geosmin.
Peptidoglycan present in cell walls.
The percent G+C ranges from 40 to 67%.
Contains various Phycobilins.
Glycogen is used as the storage product.
Some species can be toxic.

The above picture shows Oscillatoria Princeps (200x).

2. TAXONOMIC DESCRIPTION
Cells are in a trichome disc-shape and are not separated by deep constrictions. Heterocysts are not present. Oscillatoria divides in a single plane using binary fission. All species use glycogen as their storage product. They are motile due to the secretion of slime through small pores. The thin cell wall aids in gliding. There is no sheath. Oscillatoria glides at a rate of 11um/sec = 39.6 mm/hr = 396 m/year. Peptidoglycan is a major constituent of the cell wall (up to 50% of the dry weight). The cytoplasm is filled with photosynthetic membranes called thylakoids, which contain Chlorophyll a. Oscillatoria gets the green color from Chlorophyll a and the blue color from Phycocyanin. However, not all Bluegreen algae are blue-green. Phycoerythrin can be found in some, giving a red or pink pigment. The Red Sea gets its name from occasional blooms of a reddish species of Oscillatoria. The carotenoids echinone and myxoxanthophyll are present. Many species produce Geosmin, a chemical with an earthy smell to it. Gas Vacuoles are used to move vertically in the water column. Prefers to use Oxygenic Photosynthesis, some species can switch to Anoxygenic Photosynthesis if conditions demand it. An example is O. Limnetica, which lives in sulfide-rich saline ponds. H₂S strongly inhibits electron flow from Photosystem II, so O. Limnetica uses H₂S as an electron donor for Photosystem I. Sulfur granules are deposited outside the cell in that case. Some species fix nitrogen.

I have found over 35 described species in the genus Oscillatoria. There are probably more that I have no information on. Many more probably exist in areas that haven?t been researched or published. Various Oscillatoria species can be found in hot springs, freshwater, marine, estuarine, and sulfur environments.

The above picture shows Oscillatoria being collected in the field.

3. ISOLATION AND ECOLOGY
General and selective media are available and when isolated, Oscillatoria start out as small trichomes with the color of the original organism. One problem with culturing Oscillatoria is its tendency to move around, sometimes ending up on a dry surface and dying. Oscillatoria must remain moist.

Oscillatoria can be used as an indicator of water quality or Eutrophication of a water source. As a body of water becomes more eutrophic or polluted, O. rubescens increases in population as O. agardhii decreases in population. Widely distributed in nature, some species are toxic to humans and animals. Algae can enter a toxic phase and be indistinguishable from the nontoxic algae around it. Oscillatoria are known to produce both neurotoxins called anatoxins and hepatotoxins called microcystins. ?Anatoxins can block the transmission of signals from neuron to neuron and neuron to muscle, while microcystins cause bleeding in the liver. The threat is more to livestock then to humans. More research is needed into Oscillatoria in regards to uses as biological indicators and into methods to test for toxic algae.

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The picture to the left shows a typical group of Oscillatoria, while the picture to the right shows a single Oscillatoria trichome.

4. ADDITIONAL SOURCES OF INFORMATION

Atlas, Ronald. 1995. Principles of Microbiology 1^st edition. Mosby-Year Book, Inc. St. Louis, Missouri. 888 pp.

Lee, Robert Edward.1999. Phycology 3^rd edition. Cambridge University Press. New York, NY. 614 pp.

Madigan, M.T., Martinko, J.M., Parker, J. 2000. Brock Biology of Microorganisms 9^th edition. Prentice Hall. Upper Saddle River, NJ. 991 pp.

Parker, Bruce. Spring 2000. Virginia Tech. Biology 4234: Algae. 3 credit course.

5. LINKS TO OTHER SITES ON OSCILLATORIA

Cyanobacteria This site is a good general introduction to Cyanobacteria and it has a variety of info .

Cyanosite This is a webserver for Cyanobacterial research, and a good place to go for all sorts of resources. Has a good image gallery.

Phycological Society of America Useful as a search engine for finding specific research, but not much information actually on the web.