Molecular and Bioinformatic Approaches to Study Cyanobacteria and Cyanophages

Tin-Chun Chu, Ph.D. Cyanobacteria

 Algal blooms:  Usually caused by nutrient enrichment Sewage, agricultural fertilizers and industrial run-off in waterways.  Considered a threat to the water ecosystem  Produce a foul smell and an unpleasant taste to the water.  Oxygen depletion due to the decay of bloom masses.  Species of Anacystis, Microcystis, Anabaena, Cylindrospermopsis, and Nostoc commonly cause blooms in freshwater.  Some cyanobacteria can produce toxins  eg. Anabaena sp.  eg. Microcystis sp.

5/1/2013 2 BEIJING, Oct. 26 — China will spend more than $14 billion to clean up a famed lake inundated by so much pollution this year that it became a symbol of the country’s lax environmental regulation against polluting industries.

5/1/2013 3 Harmful Cyanobacterial (Algal) Blooms

Zaka lake, Santa Barbara, California

5/1/2013 4 Cyanobacteria

 Cyanobacteria (Blue-green algae)  Prokaryotic, photosynthetic organisms, which carry chlorophyll a and other photosynthetic pigments, such as phycocyanin  Gram-negative bacteria like cell wall  Aerobic, oxygenic photoautotrophs  In wide range of habitats (marine, freshwater, etc.)

 Importance  One of the oldest existing living organisms

 Responsible for O2 generation in the atmosphere  Nitrogen fixation  Major causing agent for algal blooms  Some cyanobacteria produce potent toxins thus affect human health

5/1/2013 5 Common Cyanobacteria Morphologies of a) Synechococcus sp. Synechococcus elongatus sp. PCC 6301 Synechococcus elongatus sp. PCC 7942 Synechococcus sp. CC 9605 Synechococcus sp. CC 9902 Synechococcus sp. WH8103 b) Anabaena sp. Anabaena variabilis ATCC 29413 Anabaena sp. PCC 7120 c) Gloeobacter sp. Gloeobacter violaceus PCC 7421 d) Oscillatoria sp. e) Microcystis sp. e Microcystis aeruginosa sp. PCC 7806 f) Prochlorococcus sp. Prochlorococcus marinus str. MIT 9312 Prochlorococcus marinus str. MIT 9313 Prochlorococcus marinus str. NATL2A Prochlorococcus marinus str. CCMP 1375 Prochlorococcus marinus str. CCMP 1986 5/1/2013 6 Synechococcus sp. IU 625/ Anacystis nidulans (AN)

. Freshwater cyanobacteria, blue-green algae, obligate photoautotroph.

. Rod-shaped prokaryote, cell wall similar to the gram negative type, 1~2 M in length. Lab photos

. Good environmental pollution indicators, because of its simplicity, size, ease of growth and heavy metal response.

5/1/2013 7 Cyanophage

 Viruses that infect cyanobacteria

 Ubiquitous and abundant

 Modulating cyanobacterial populations, affect primary productivity and water quality

 Extremely diverse– Myoviridae, Siphoviridae and Podoviridae Photograph taken by Mike Ganger (MSU)

5/1/2013 8 Cyanophage AS-1

 Hosts: Anacystis nidulans and Synechococcus cedrorum

 Family: Myoviridae

 Icosahedral head (90 nm) + long tail (22 nm x 244 nm).

. 90 kb linear ds DNA (53-54% GC content)

. Similar to T4 in morphology Barkley and Desjardins, AEM, 1977, p971-974 5/1/2013 9