Matters Microbial #63: A Symphony of Cyanobacteria

Today, Dr. Nathan Algren, Associate Professor of Biology at Clark University, joins the #QualityQuorum to discuss the centrality of cyanobacteria to our biosphere, the viruses that prey upon them, and his interests in outreach and science-oriented art.

Host: Mark O. Martin

Guest: Nathan Ahlgren

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• An overview of the cyanobacteria.
• An overview of Prochlorococcus.
• An overview of marine bacteriophages.
• The Great Oxidation Event Cyanobacteria are thought to have radically changed our planet 2.5-3.5 billion years ago by producing oxygen through photosynthesis. In essence, they and other microbes are the original terraformers.
• The Purple Earth Hypothesis Photosynthesis as we know it, using chlorophyll, may have evolved after another way of doing photosynthesis, with retinal that looks purple. This means that our planets and other ‘younger’ planets may look or have looked purple rather than green.
• Self-assembly of viral capsids, as modeled by 3D-printed parts (Art Olson)
• TED talk from Penny Chisholm on Prochlorococcus
• Co-occurring Synechococcus ecotypes occupy four major oceanic regimes defined by temperature, macronutrients and iron  Study showing how different populations of Synechococcus occupy different niches and regions of the oceans according to their adaptations to temperature and nutrients.
• Long-term stability and Red Queen-like strain dynamics in marine viruses  Study showing turnover of strains within relatively stable phage populations.
• Viral treadmills in the ocean—running to stand still  Companion ‘behind the paper’ article.
• Diverse Marine T4-like Cyanophage Communities Are Primarily Comprised of Low-Abundance Species Including Species with Distinct Seasonal, Persistent, Occasional, or Sporadic Dynamics  Paper showing cyanophage ‘species’ have different time patterns in the oceans.
• Rapid diversification of coevolving marine Synechococcus and a virus Study showing stable co-existence and co-evolution of a single Synechococcus host and phage over time. The emergence of resistance hosts and phage that overcome them demonstrate the principles of the Red Queen hypothesis and phage-host ‘arms race’.
• Present and future global distributions of the marine Cyanobacteria Prochlorococcus and Synechococcus Figure from this paper is in the presentation. Shows modeled distributions of Pro and Syn across the globe. They also use this to estimate a ~25% contribution of Pro and Syn to global net primary productivity in the oceans.
• Link to 3D prints that Dr. Ahlgren made an are available on NIH page
• Some resources on how to 3D protein structures: I like this guide on the practical guide of how to do actually to do it (going from PDB to print files):
• A link to another resource for 3D printing of protein structures.
• Dr. Ahlgren’s faculty website.
• Dr. Ahlgren’s laboratory website with many fascinating links.

Intro music is by Reber Clark

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