Matters Microbial

Matters Microbial #112: Bacterial Size, Stress, and Antibiotic Resistance October 17, 2025 Today Dr. Petra Levin, the George and Irene Freiberg Professor of Biology at Washington University in St. Louis joins the #QualityQuorum to discuss her work with bacterial cell size, environmental stress on bacteria, and antibiotic resistance. Host: Mark O. Martin Guest: Petra Levin Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode An overview of the periplasm, found in Gram negative bacteria. An overview of beta-lactam antibiotics. The field of quantitative microbiology. An overview of B. subtilis.  An overview of E. coli.  An overview of Klebsiella.  The biography of Barbara McClintock, “A Feeling for the Organism.” A video explanation of the lac operon of E. coli. The LTEE program (Long Term Evolution Experiment) founded by Dr. Rich Lenski. The nomenclature of monoderm and diderm bacteria. A video explanation of peptidoglycan in bacteria. Penicillin binding proteins (PBP) and antibiotic resistance. A video about cell division in E. coli. A famous article coauthored by Dr. Elio Schaechter that describes cell growth and cell size in bacteria. A related article by Dr. Levin and colleagues. An overview of ESKAPE bacteria. An article from Dr. Levin’s research group describing the relationship between pH and antibiotic resistance. An article about persister cells and their relevance to antibiotic resistance. Dr. Levin’s faculty website. Dr. Levin’s very interesting laboratory website. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #111: Shocking Tales of Metal-Loving Microbes October 10, 2025 Today Dr. Jeff Gralnick, Professor of the Department of Plant and Microbial Sciences at the University of Minnesota joins the #QualityQuorum to tell us a shocking story about how his research group studies the relationship between electrons, microbes, and metals.   Host: Mark O. Martin Guest: Jeff Gralnick Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode An article about Nobel Prize winner Albert Szent-Györgyi. The Soudan Formation Iron Mine discussed during the podcast. An article on Banded Iron Formations. An article about the Oxygen Crisis early in Earth’s history. An overview of the bacterium Shewanella. An overview of the bacterium Geobacter. An overview of microbial redox reactions. The “bacterial battery” we discussed: the Mudwatt. An article on benthic microbial fuel cells. An article on extracellular electron transfer by bacteria. The laboratory of Dr. Daniel Bond at the University of Minnesota, and colleague of Dr. Gralnick’s. An essay on microbial nanowires. An essay on cable bacteria, which was the topic of #MattersMicrobial podcast #101 with Dr. Nicole Geerlings. The new field of electromicrobiology. The relationship between Shewanella and fish!  An article by Dr. Gralnick and colleagues on the Shewanella and fish (and bacteriophage) association. The article about Jon Beckwith (by Howard Shuman) discussed in the podcast:  “With Toothpicks and Logic.” Dr. Gralnick’s faculty website. Dr. Gralnick’s laboratory website. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #110: Enumerating the Microbiome October 3, 2025 Today Dr. Sean Gibbons, Associate Professor at the Institute for Systems Biology, returns to the #QualityQuorum to tell us about how he and his colleagues are able to listen very carefully to the microbiome to uncover important hints about health. Host: Mark O. Martin Guest: Sean Gibbons Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode Here is the article from Dr. Norm Pace and coworkers on the showerhead microbiome referenced in the podcast. Here is a nonspecialist summary of Dr. Pace’s work on the showerhead microbiome and mycobacteria. Here is a link to a prior episode of this podcast with Dr. Ameet Pinto on microbiology of the water supply. Here is Dr. Gibbon’s earlier visit to this podcast. An overview of the difference between microbiome and microbiota. An article about the “misnumbering” of the number of microbial to human cells in people.  Here is a nonspecialist summary. An overview of metagenomics. An overview of qPCR. An overview of flow cytometry. Plato’s Allegory of the Cave, discussed in this podcast. A cautionary tale about determining a cancer microbiome, as discussed in this podcast. An article by Dr. Gibbons and colleagues described in this podcast about how to estimate microbial biomass directly. An article by Dr. Gibbons and colleagues described in this podcast about how to estimate microbial growth rates in the human gut using metagenomics. An article by Dr. Gibbons and colleagues described in this podcast about how to use metagenomics to determine dietary habits. The website for Dr. Gibbon’s research group. The faculty website for Dr. Gibbons at ISB. Courses on microbiome sciences online at ISB. The website for Institute for Systems Biology. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #109: Bat-Crazy About Rabies September 26, 2025 In honor of World Rabies Day, Dr. Rodney Rohde, Regents Professor at Texas State University,  joins the #QualityQuorum to discuss rabies and some of the strategies used to limit the influence of that devastating viral disease. Host: Mark O. Martin Guest: Rodney Rohde Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode An overview of rabies from the CDC. A historical overview of rabies and Louis Pasteur. The global impact of rabies. Bats and rabies. A podcast exploring rabies and myths about vampires and werewolves. A wonderful video about rabies SO worth your time. A video with three physicians about rabies. A detailed review of rabies and the rabies virus. The lifecycle of the rabies virus. Various tests for rabies. The vaccines for rabies. Rabies research at the CDC. Use of an oral rabies vaccine to eliminate epizootic rabies in coyotes and gray foxes in Texas. Information about World Rabies Day. The Contagion Live website, including podcasts by Dr. Rohde. A video from Dr. Rohde about medical laboratory science. A video from Dr. Rohde about rabies. Dr. Rohde’s biography from the American Society for Microbiology. Dr. Rohde’s faculty website. Dr. Rohde’s personal website. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #108: Neanderthal Oral Health, Ancient Bacteria and DNA September 19, 2025 Today, Dr. Laura Weyrich, Associate Professor of Anthropology at Pennsylvania State University,  joins the #QualityQuorum to discuss the paleo oral microbiome! We will learn if our ancestors had the same kind of resident microbes as we do. In addition, we will learn about ancient DNA and what it can tell us. Host: Mark O. Martin Guest: Laura Weyrich Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode An obituary for my late and much missed microbiologist friend, Dr. Kimberly Walker. A link to Episode #9 of #MattersMicrobial, with Sebastian Cocioba.  The ethics of collecting samples from deceased humans, both ancient and modern. An overview of the efforts to study ancient DNA.  Here is another review on that topic. The importance of proper controls for the study of low DNA abundance samples—the famous “kitome” often observed.  Here is an article by Dr. Weyrich and colleagues on this topic, as well. A recent article using human bones to detect Yersinia pestis, the causative agent of plague.  An overview of the oral microbiome. An article describing how dental calculus can be used to recover ancient DNA. An article by Dr. Weyrich and colleagues describing the human oral microbiome pre and post Industrial Revolution in Great Britain. A video describing our Neanderthal ancestors. An article by Dr. Weyrich and colleagues describing the Neanderthal oral microbiome and related issues. A fine video by Dr. Weyrich describing her research program. Dr. Weyrich’s faculty website. Dr. Weyrich’s research team website (SO INTERESTING). Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #107: Listeria Sprouting Hysteria? September 11, 2025 Today, Dr. Lisa Gorski, a microbiologist and food safety consultant recently retired from the US Department of Agriculture, Agricultural Research Service, joins the #QualityQuorum to discuss the facts about the disease causing bacterium named Listeria. We will learn about the organism, the disease listeriosis, and food safety. Host: Mark O. Martin Guest: Lisa Gorski Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode A description of the ice nucleation phenomenon carried out by many bacteria. An out of print book by Dr. Jo Handelsman that explained the ice nucleation experiment I often use when I teach. An overview of ice nucleation protein. A very nice video demonstration of ice nucleation activity I created many years ago with Puget Sound students. The relationship between ice nucleation protein and the commercial substance “SnowMax.” Information from the Centers for Disease Control on Listeria.  A description of listeriosis, caused by Listeria. A cute plush toy depicting Listeria, by the Giant Microbes company. A recent review article on Listeria and listeriosis. A video depicting “actin rockets” allowing Listeria to move within eukaryotic cells. A review article on actin-related motility of intracellular bacteria. A description of a recent Listeria outbreak. Advice for consumers regarding avoiding listeriosis.   The United States Department of Agriculture group on food safety and surveillance.  Articles by Dr. Gorski and colleagues on topics under discussion today. Dr. Gorski’s LinkedIn profile. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #106: Cells Without Walls – Full-Frontal Bacteria September 6, 2025 Today, Dr. Dennis Claessen of Leiden University’s Institute of Biology joins the #QualityQuorum to discuss how some bacteria lose their cell walls, the costs and advantages of that strategy, and how such cells can shed light on antibiotic resistance and even pathogenesis!  Host: Mark O. Martin Guest: Dennis Claessen Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode Website for the Institute for Biology at Leiden University in the Netherlands. The website of Micropia, the world’s best known (and perhaps only) museum devoted to microbial life, in Amsterdam, the Netherlands. The “Tardigrade Chair” at Micropia. The art of Dr. Lizah van der Aart. A video about the cell wall of bacteria. A useful overview of the cell wall of bacteria. A useful review article about the cell membrane of bacteria. An overview of peptidoglycan. The discovery of L-forms of bacteria, and Emmy Klieneberger-Nobel, who named them in 1935. A review article on L-forms (cell wall deficient) bacteria. An article relating L-forms of bacteria and the ability to resist certain antibiotics.  Here is another article. An article suggesting that L-forms could shed light on the origins of life. An article suggesting that L-forms are a strategy for dealing with stress. An article from Dr. Claessen’s research group showing that L-forms of bacteria are often resistant to bacteriophage infection—and in a reversible fashion. A video presentation by Dr. Claessen. The faculty website of Dr. Claessen. The research website for Dr. Claessen’s group. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #105:  Snails Farming Bacteria in the Deep Sea August 29, 2025 Let’s take a deep dive into chemoautotrophy!  Today, Dr. Roxanne Beinart, Associate Professor of Oceanography at the University of Rhode Island, joins the #QualityQuorum to discuss how some marine creatures use bacterial symbioses to provide organic compounds for growth and reproduction.  Host: Mark O. Martin Guest: Roxanne Beinart Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode An appreciation of the late Dr. Moselio (Elio) Schaechter from his friends at the blog “Small Things Considered.” A video from This Week in Microbiology appreciating Elio Schaechter. A video describing deep sea symbioses. A video by the great Dr. Colleen Cavanaugh about chemoautotrophy/chemosynthesis. An overview of chemoautotrophic strategies in the ocean. An overview of hydrothermal vents. A video review of  thiotrophic (sulfur based) symbiotic associations. A video about hydrothermal vent exploration. A review of hydrothermal vent communities. Alvinella, the extremophilic bristleworm discussed in this episode (includes videos). An article by Dr. Beinart and colleagues, describing how a hydrothermal vent community is disrupted by a volcanic eruption. A report on the 2020 submarine volcano eruption discussed in this episode. An interesting article about studying deep sea symbioses, coauthored by Dr. Beinart.  A great video by Dr. Beinart about her research.  Dr. Beinart’s research team website. Dr. Beinart’s faculty webpage. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #104: Antibiotic “Tolerance” and Biofilms August 21, 2025 Today, Dr. Boo Shan Tseng, Associate Professor at the University of Nevada Las Vegas School of Life Sciences, joins the #QualityQuorum to discuss bacterial biofilms and antibiotic tolerance.  Host: Mark O. Martin Guest: Boo Shan Tseng Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode A video overview of biofilms. A comprehensive review article on biofilms. An article describing the impact biofilms have on disease. An article describing the impact of biofilms on implanted medical devices. A link to the Center for Biofilm Engineering at Montana State University that has MANY links of interest. An overview of biofilm development. An overview of confocal laser microscopy. Studying biofilms in flow cells. An article about the role proteins play in biofilm formation, which intersects with the Tseng group’s research. The technique of single cell RNA seq. The technique of mRNA-FISH. An article about porins in bacteria, and how that can relate to antibiotic resistance. An article by Dr. Tseng and coworkers on the eDNA and biofilms discussed today. A lovely video of Dr. Tseng talking about the research she and her colleagues carry out in the laboratory. Dr. Tseng’s biography from the American Society for Microbiology. Dr. Tseng’s laboratory group website with wonderful links and images. Dr. Tseng’s faculty website. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #103: Giant Bacteria and Bigger Questions August 14, 2025 Today, Dr. Jean-Marie Volland, Assistant Professor at the University of California in Santa Barbara joins the #QualityQuorum to discuss the discovery and analysis of the (so far) largest bacterium known:  Thiomargarita magnifica, which can be a centimeter long! Definitely #OMG and #WTM! Host: Mark O. Martin Guest: Jean-Marie Vollard Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode Here is a review article discussing the environmental persistence of antibiotic resistance genes. Here is a link to Episode 41 of this podcast, with Dr. Esther Angert, on the wily ways of Epulopiscium. A review article regarding “giant bacteria.” A video explaining the surface area versus volume issue discussed on this podcast. An interesting article exploring how much “territory” is within a bacterial cell; this is relevant to bacterial polyploidy. A review of Epulopiscium, the first of the giant bacteria described. Here is a video of Epulopisicum.   An article describing polyploidy in Epulopiscium.  A review of Thiomargarita nambiensis, another giant bacterium with an interesting strategy. Here is a video of T. nambiensis.  An essay from “Small Things Considered” about the very, very strange world of Achromatium, which is so worth your time. The first report of Thiomargarita magnifica, the world’s largest bacterium (thus far) by Dr. Volland and coauthors. Here is a report on this discovery for novice micronauts. A great review about giant microbes by Dr. Volland. A more recent article on T. magnifica by Dr. Volland and colleagues. A video regarding T. magnifica. A video by Dr. Volland describing T. magnifica work. A lovely essay regarding how Dr. Volland and family trekked California searching for giant microbes. Don’t miss! The research lab website for Dr. Volland and colleagues, with so much interesting information. The faculty website for Dr. Volland at UC Santa Barbara. Intro music is by Reber Clark

Matters Microbial #102: Teaching Through the Issues with Microbes! July 31, 2025 Today, Dr. Davida Smyth, Professor of Biology and Deputy Director of the National Center for Science and Civic Engagement at Texas A&M University-San Antonio joins the #QualityQuorum to discuss her impressive work using microbiology to engage students at the intersection of cutting edge research and current events. #MicrobialLiteracy! Host: Mark O. Martin Guest: Davida Smyth Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode The American Society for Microbiology Carski Award website. The American Society for Microbiology Distinguished Lecturer website. The concept of “classroom agreements.” The 10:1 (microbial cells to human cells) story, and a related article. The 3-2-1 approach to learning in the classroom. Dr. Smyth’s “How Toilets Changed the World” class. The American Society for Microbiology Curriculum Guidelines. The National Science Foundation’s “Vision and Change” website describing improvements in biology education. The American Society for Microbiology profile for Dr. Smyth. A video seminar by Dr. Smyth describing open science in undergraduate education. The website for the National Center for Science and Civic Engagement. Dr. Smyth’s faculty website. Dr. Smyth’s superb research website. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #101: Electrifying News about Cable Bacteria July 25, 2025 Today, Dr. Nicole Geerlings from the University of Vienna in Austria joins the #QualityQuorum to discuss some of the wonderful work she and colleagues have carried out studying the wild, weird, and wonderful world of cable bacteria, which can conduct electricity over microbially enormous distances!  Definitely time for #OMG and #WTM! Host: Mark O. Martin Guest: Nicole Geerlings Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode This just became available:  a wonderful short introduction to day’s topic, the cable bacteria, from Asimov Press.  It is an absolute must read for everyone interested. Here is a link to the Summer Science Program, a wonderful outreach program for high school juniors. An essay about Nobel Prize winning Albert Szent-Györgyi, who stated that life was a matter of electrons finding a place to rest.  Here is a short video introduction to his work. A video introduction to microbial metabolism. A video introduction to electron transport.  Remember that bacteria and archaea are VERY skilled at using different electron donors and acceptors than eukaryotic life. The really fun concept of the “Jagendorf Jump,” showing electron transport vs. pH in chloroplasts. An overview of the microbial fuel cell concept.  Here is a nice overview I highly recommend. A commercial source for you to build your own microbial fuel cell. A DIY approach to building a MFC.  An ESSENTIAL overview to the idea of electrons in microbial sediments. A review article about cable bacteria.  Here is another fine review. This is a third great introduction to cable bacteria. And here is a video overview.   An article by Dr. Geerlings and colleagues describing cable bacteria for new #Micronauts.  HIGHLY RECOMMENDED. An review of stable isotope probing in microbiology. Here is a video seminar using SIP in microbiology. An overview of Nano-SIMS and how it is used in microbiology.  Here is another review.   A deeply wonderful article by Dr. Geerlings and colleagues suggesting that inactive cells with the “microbial cable” are still conducting electrons! Dr. Geerlings postdoctoral scholar website. Links and References on Cable Bacteria from Dr. Geerlings: 1. Here is a website from the group of Prof. Dr. Filip Meysman from the University of Antwerp, which includes a great video on the electron conductivity of cable bacteria. 2. The first paper describing redox half-reactions separated by long-distance electron transport. Nielsen, L. P., Risgaard-Petersen, N., Fossing, H., Christensen, P. B., and Sayama, M. (2010). Electric currents couple spatially separated biogeochemical processes in marine sediment. Nature 463, 1071–1074. doi: 10.1038/nature08790 3. The paper describing the discovery of cable bacteria. Look into the supplemental material for the excellent experimental set-up to prove that the cable bacteria are the ones doing the long-distance electron transport. Pfeffer, C., Larsen, S., Song, J., Dong, M., Besenbacher, F., Meyer, R. L., et al. (2012). Filamentous bacteria transport electrons over centimetre distances. Nature 491, 218–221. Doi: 10.1038/nature11586 4. A paper that dives into the conductivity of the cable bacteria network and shows that these fibres can conduct electrons just as well as a copper wire. Meysman, F. J. R., Cornelissen, R., Trashin, S., Bonné, R., Martinez, S. H., van der Veen, J., et al. 2019. A highly conductive fibre network enables centimetre-scale electron transport in multicellular cable bacteria. Nat. Commun. 10:1–8. doi: 10.1038/s41467-019-12115-7 5. This paper describes how cable bacteria activity generates a layer of iron oxyhydroxides on the top of the sediment layer and how this delays the release of sulfide into the water column for several weeks in a seasonally hypoxic basin in the Netherlands. Seitaj, D., R. Schauer, F. Sulu-Gambari, et al. 2015. “Cable Bacteria Generate a Firewall Against Euxinia in Seasonally Hypoxic Basins.” Proceedings of the National Academy of Sciences of the United States of America 112: 13278–13283. 6. This paper describes how the catabolic division of labor is coupled to an anabolic division of labor where cells reducing oxygen cannot grow and therefore provide a “community service” for the rest of the filament. Nicole M. J. Geerlings, Cheryl Karman, Stanislav Trashin, Karel S. As, Michiel V. M. Kienhuis, Silvia Hidalgo-Martinez, Diana Vasquez-Cardenas, Henricus T.S. Boschker, Karolien de Wael, Jack J. Middelburg, Lubos Polerecky, and Filip J.R. Meysman. Division of labor and growth during electrical cooperation in multicellular cable bacteria. Proc. Natl. Acad. Sci. U.S.A. 117, 5478–5485. Doi: 10.1073/pnas.1916244117   Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #100: What’s the Buzz on Phage Therapy for Honeybees? July 14, 2025 Today, Dr. Heather Hendrickson from the University of Canterbury in New Zealand joins the #QualityQuorum to discuss the research she and her team are conducting on bacteriophage therapy to protect vulnerable honeybees from bacterial infections. Host: Mark O. Martin Guest: Heather Hendrickson Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode Here is the website for a former undergraduate research student of mine, Dr. Paula Welander, now a professor and administrator at Stanford University.  Yes, I am proud. Here is a link to another former undergraduate research student of mine, Dr. Krista Venecia Edmiston, now a professor at California Health Sciences University.  Yes, I am proud. A review on cell shape in bacteria. A review on the cytoskeleton of bacteria and archaea. I am a great admirer of Dr. John Roth, and his clearheaded and direct approach to microbial genetics.  Here is his academic website with many publications. An article about the causative agent of American Foulbrood, Paenibacillus larvae. An overview of American Foulbrood’s impact on honeybees. The honeybee lifecycle. Beemites and honeybees. A video overview of bacteriophage therapy against bacterial diseases. An explainer of bacteriophage plaques. A video overview of lytic versus lysogenic bacteriophages. Dr. Graham Hatfull and his simply amazing SEAPHAGEs program, teaching so many people about isolating and studying bacteriophages. An article from Dr. Hendrickson’s laboratory exploring cell shape in bacteria. An article from Dr. Hendrickson’s laboratory explaining the importance of protecting honeybees from American Foulbrood, and the approach her laboratory uses. An article from Dr. Hendrickson’s laboratory describing a community based approach to search for bacteriophages of Paenibacillus larvae. An article from Dr. Hendrickson’s laboratory analyzing the types of Paenibacillus attacking bacteriophages isolated in New Zealand. An article from Dr. Hendrickson’s laboratory describing an improved method for isolating bacteriophages. A truly great video from Dr. Hendrickson some years ago, explaining her research.  This is a “must see.” Dr. Hendrickson’s faculty webpage. Dr. Hendrickson’s informative research group website. This section of Dr. Hendrickson’s research group website is devoted to outreach, and so very worth your time. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #99: Albert Kluyver—Microbial Unity and Diversity in Metabolism July 10, 2025 Today, Dr. Dianne Newman of Caltech joins the #QualityQuorum live at ASM Microbe in Los Angeles, to discuss the role that Albert Kluvyer played in helping microbial scientists to understand the unity and diversity to be found in microbial metabolism. Host: Mark O. Martin Guest: Dianne Newman Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode A review article by Roberto Kolter about the history of microbiology. An overview of the “Delft School” of microbiology.  Here is another article on that topic. The 1924 article by Albert Kluyver that Dr. Newman references—very much worth you time. A video overview of microbial metabolism.  Here is a recent article on that topic. A short biography of Albert Kluyver. Here is another article on that topic. A wonderful 2023 video seminar by Dr. Newman exploring the unity and diversity of microbial metabolism.  Much recommended. Dr. Newman’s faculty website. Dr. Newman’s very impressive research group website. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #98: Nesting Dolls of Endosymbiosis July 3, 2025 Today, Dr. John McCutcheon of Arizona State University joins the #QualityQuorum to discuss the work he and his research group do to investigate the strategies by which microbes become symbionts of other cells. After all, the mitochondria and chloroplasts of eukaryotic cells, including yours, were once bacteria! Host: Mark O. Martin Guest: John McCutcheon Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode A video about the symbiosis of Hydra virdissima, which captured my heart when I was young.  Look at those symbiotic algae!  Here is an overview of this topic. A video describing the Rhizobium – legume nitrogen fixing symbiosis in all of its glory—by my PhD advisor, the great Dr. Sharon Long.  Here is an overview of this topic.   An appreciation of Paul Buchner’s very important book, “Endosymbiosis of Animals with Plant Microorganisms.” A wonderful review by Dr. McCutcheon on how symbioses form. A wonderful essay by Ed Yong about an event that made eukaryotic cells possible:  how bacteria became mitochondria. A story about an anaerobic protist that lost its mitochondria completely. A bacterial symbiont of mitochondria, the “midichlorian.” The recent discovery of a new integrated symbiont that has become an organelle, the nitrosome. The “X-bacteria” and amoebae story. A retrospective on endosymbiosis, and Paramecium based on Tracey Sonneborn’s work. An essay on aphids and bacteria. An article on the Moranella/Tremblaya symbiosis. An article on “bacteria inside other bacteria” found in several symbioses, written by Dr.McCutcheon and colleagues. Genomic instability in bacterial endosymbionts. An article on cicadas and bacterial endosymbionts from Dr. McCutcheon and colleagues. An article on mealybugs and bacterial endosymbionts from Dr. McCutcheon and colleagues. Dr. McCutcheon’s thoughts on his career path (so worth reading). The Center for Mechanisms of Evolution research institute in which Dr. McCutcheon works. Dr. McCutcheon’s faculty website. Dr. McCutcheon’s (and his research team’s) wonderful research website. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #97: Microbes in the Air (Way) June 27, 2025 Today, Dr. Ari Kozik, Assistant Professor at the University of MIchigan joins the #QualityQuorum to discuss the work she and her research group do to investigate microbes living within the lung and their relationship to health as well as microbiology outreach and representation. Host: Mark O. Martin Guest: Ari Kozik Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode A wonderful discussion of airway microbes. A thought provoking article about microbes in our breath! Geography of mouth to lung and relevance to health. Relevance and definition of the term “microaspiration.” Some general characteristics of anaerobic bacteria A commercial video explaining the basics of anaerobic chambers An article about the airway microbiome A video overview about biofilms Kombucha sculpture as discussed briefly. A relevant article from Dr. Kozik’s and coworkers. A video from This Week in Virology including Dr. Kozik about representation in the microbial sciences (very important to watch). Dr. Kozik’s important efforts in science outreach. Dr. Kozik’s faculty website. Dr. Kozik’s research group website. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #96: Molecular Microbiology in High Schools June 19, 2025 Today, Bob Kuhn, biotechnology teacher at the Fulton County Schools Innovation Academy STEM high school in Alpharetta, Georgia joins the #QualityQuorum to discuss his strategies for teaching molecular microbiology skills and concepts to high school students — and why that matters. Host: Mark O. Martin Guest: Bob Kuhn Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode An article on Mr. Kuhn’s original microbiological interest:  salt marsh foraminifera. Another interest:  a video of the beautiful organism Volvox. An overview of the fantastic world of protists. A classroom CURE that Mr. Kuhn uses:  the Tiny Earth program. A classroom CURE that Mr. Kuhn uses:  the SEAPHAGES program. A classroom CURE that Mr. Kuhn uses:  the Evolving Stem program. A classroom CURE that Mr. Kuhn uses:  the Discover the Microbes Within program. Mr. Kuhn’s classroom received help from the University of Georgia Microscopy Center. A video of the Wolbachia Project with which Mr. Kuhn has collaborated for years. An overview of wonderful and various isopods, including the “roly polies” used in some Wolbachia work. The Journal of Emerging Investigators, in which some of Mr. Kuhn’s high school students have published. The LTEE program that studies evolution in E. coli.   The Experiment.com program that supported some of Mr. Kuhn’s students. The very inspirational MEGAplate video that demonstrates how quickly antibiotic resistance can occur. Innovation Academy STEM program in Georgia, where Mr. Kuhn works with high school students. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #95: Bacteria and Aphids — A Symbiotic Story June 12, 2025 Today, Dr. Tory Hendry, Associate Professor of Microbiology at Cornell University, joins the #QualityQuorum to tell us about the relationship between plant munching aphids and fluorescent Pseudomonas . . . and why we should care. Host: Mark O. Martin Guests: Tory Hendry Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode An overview of siderophores in microorganisms. An essay about aphid life cycle and characteristics. An article describing parthenogenesis in aphids. An essay describing aphids and color vision. The agricultural costs of aphids as pests. An article describing aphids and one type of bacterial symbiont. An overview of microbes of the phyllosphere. An overview of quorum sensing. An overview of pyoverdin, a fluorescent siderophore.  An old essay I wrote for the Small Things Considered blog about semiochemicals, bacterial, and insect predation. A nice description of the work Dr. Hendry talked about during today’s podcast.  The actual article by Dr. Hendry and collaborators. A preprint by Dr. Hendry’s research group, following up on the above research.  Dr. Hendry’s faculty website. Dr. Hendry’s research group website (with SO MANY cool projects to think about, including the topic discussed today). Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #94: One Health and Microbiomes Everywhere June 5, 2025 Today, Dr. Seth Bordenstein and Dr. Nichole Ginnan of Pennsylvania State University join the #QualityQuorum to tell us about their new publication linking One Health to the myriad microbiomes that exist all around us through the lens of the holobiome—and an opportunity to see the world in a different fashion. Host: Mark O. Martin Guests: Seth Bordenstein and Nichole Ginnan Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode Michele Banks microbially themed art can found at her Etsy site.  Highly recommended! The paper under discussion today, with Dr. Ginnan as first author.  You will see that coauthors include Dr. Bordenstein, and two previous visitors to the #MattersMicrobial podcast!  Thank you Erika and Francisco. Dr. Bordenstein’s first podcast with #MattersMicrobial for those who missed it. A review of the One Health concept. The One Health Microbiome Center at Penn State. A very clear overview of the holobiont concept and biology, authored by Dr. Bordenstein and colleagues. Another longer review on this topic. The faculty website for Dr. Ginnan. The faculty website for Dr. Bordenstein. The research website for Dr. Ginnan. The research website for Dr. Bordenstein. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com

Matters Microbial #93: Preventing Antibiotic Resistance May 29, 2025 Today’s episode was an in-person podcast at the University of Texas Austin!  Dr. Despoina Mavridou, Assistant Professor of Molecular Biosciences, joins the #QualityQuorum to discuss how her research group improves antibiotic effectiveness by impeding protein folding, and why this matters in the fight against antimicrobial resistance. Host: Mark O. Martin Guest: Despoina Mavridou Subscribe: Apple Podcasts, Spotify Become a patron of Matters Microbial! Links for this episode Here is a link to a wonderful video of the #LuxArt by UT-Austin students during my visit. Please give it watch and enjoy the creativity and positive #MicrobialPR. An effective TED talk by science journalist Maryn McKenna describing the threat of AMR in an accessible fashion. A CDC report on the growing threat of AMR. A review article about antibiotics. An overview of how bacteria become resistant to antibiotics.  A very recent review of the cell wall of bacteria—often the target of antibiotics. A video overview of beta-lactam antibiotics and resistance mechanisms. An overview of how protein folding is related to activity of proteins…including AMR gene products. A wonderful article by Dr. Mavridou and coworkers, describing how altering protein folding in bacteria can make them more vulnerable to antibiotics. A less technical version of the above article; well worth your reading. Dr. Mavridou’s faculty website. Dr. Mavridou’s research group website, which is most interesting. Intro music is by Reber Clark Send your questions and comments to mattersmicrobial@gmail.com