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Clues beginning to emerge on asymtomatic SARS-CoV-2 infection
Back in November of 2020, during the first wave of the COVID-19 pandemic, I was teaching an in-person microbiology laboratory. One of my students had just been home to see his parents, and they all c…
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Could there maybe be better uses of genetics and probiotics?
Professor Meng Dong and his laboratory have created a probiotic that can metabolize alcohol quickly and maybe prevent some of the adverse effects of alcohol consumption. The scientists cloned a highl…
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ChatGPT is not the end of essays in education
The takeover of AI is upon us! AI can now take all our jobs, is the click-bait premise you hear from the news. While I cannot predict the future, I am dubious that AI will play such a dubious role in…
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Fighting infections with infections
Multi-drug-resistant bacterial infections are becoming more of an issue, with 1.2 million people dying of previously treatable bacterial infections. Scientists are frantically searching for new metho…
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A tale of two colleges
COVID-19 at the University of Wisconsin this fall has been pretty much a non-issue. While we are wearing masks, full in-person teaching is happening on campus. Bars, restaurants, and all other busine…
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News

The earth’s family tree just got bigger


  Professor Jillian Banfield’s group has been research the diversity of various communities for many years. As the power of DNA sequencing has moved from a being able to generate a 500 bp in 2 weeks in the 1980, to thousands of basepairs a day in the 1990’s, to hundreds of thousands in 2000, and now with illumina technology, billions of base pairs a day, so has our understanding of what makes up the environment. Up until a few years ago, a molecular census of of a microbial community would involve isolating the genes that code for the ribosome and sequencing them. That is, until now…

In an experiment by Brown et al. the power of next-generation sequencing was focused to take a molecular census of an aquifer adjacent to the Colorado River near the town of Rifle, Colorado. In the process of the experiment, they did something clever. They used a unusually small filter to trap the bacteria for harvest instead of the typical 0.45 µm filter often used in these types of experiments. This trapped very small bacteria, that are often lost. In addition, they sequenced all the DNA, not just the ribosomal genes, thus obtaining much more information about the microbes genetic makeup.

Eight complete draft genomes and 789 partial genomes were constructed. There were some big surprises. More than 15% of the microbes found were part of a new radiation of phyla, in fact these candidate phyla radiation (CPR) bacteria are so far removed from other life forms, Bacteria, Archaea, and Eukarya, that they probably need to be placed into their own domain. CPR bacteria have a limited metabolic ability and probably depend upon other organisms to obtain the nutrients they need, explaining the inability to culture them. In addition, their ribosomal RNA genes are split by introns, meaning they would not be picked up in previous molecular surveys. In other words, we didn't know they were there because we didn't know how to look for them! In the coming years the CPR bacteria will redefine exactly what life is on this planet.