Matters Microbial

Matters Microbial #141: How Tardigrades Survive What We Do To Them October 20, 2026

Today Dr. Molly Jane Kirk, postdoctoral scholar in the Department of Molecular, Cellular, and Developmental Biology at UC Santa Barbara, joins the quality quorum to discuss her research fascination with the biology and resilience of a microscopic multicellular eukaryote, the famous tardigrade.

Host: Mark O. Martin

Guest: Molly Jane Kirk

Download MM141 (40 MB MP3, 66 mins)

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Links for this episode

• Here is a link to ASM's "Agar Art" program, where participants create art by "painting" with bacteria.
• Here is a link to some of the luminous art projects by Dr. Hunter Cole.
• Here is a link to some of the luminous art projects by Dr. Siouxsie Wiles.
• Here is a link to a #LuxArt session I did recently at the University of Texas Austin.
• A wonderful overview of tardigrades.
• A video presentation about tardigrades.
• An overview of organisms that possess multiple extremophilic traits: polyextremophily.
• The concept of cryptobiosis in tardigrades.
• A recent review article on tardigrade genomics and responses to stress.
• An overview of how tardigrades enter dormancy or the "tun" state.
• An article on the evolution of tardigrades.
• A video overview of DIC microscopy.
• A book that describes how physics works for very small organisms.
• An essay on hypergravity and biology.
• The concept of biological vitrification and intrinsically disorder proteins.
• An overview of the nervous system of tardigrades.
• An article on the imposter syndrome, of great interest to Dr. Kirk.
• Here is a preprint of an article on the imposter syndrome, authored by Dr. Kirk.
• A preprint by Dr. Kirk and colleagues, describing how tardigrade biology makes it resilient to physical damage.
• A description of the NIH K99 grant program, awarded to Dr. Kirk to transition into a faculty position.
• The laboratory of Dr. Joel H. Rothman, the postdoctoral advisor of Dr. Kirk.
• Dr. Kirk's fascinating website.

Intro music is by Reber Clark

Send your questions and comments to [email protected]

Matters Microbial #140: Out of Many, One — Coral and Jellyfish Holobionts October 7, 2026

Today Dr. Monica Medina, Professor in the Department of Ecology and Evolutionary Biology at UCLA, joins the quality quorum to discuss how organisms are made up of myriad other organisms—the holonbiont concept. Dr. Medina and her research group focus on studying this in jellyfish and coral.

Host: Mark O. Martin

Guest: Monica Medina

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Links for this episode

• A link to my host city in New Zealand, Christchurch.
• A link to the School of Biological Sciences at the University of Canterbury in Christchurch New Zealand.
• The website for the laboratory of Dr. Tom Miller of UC Riverside.
• A recent video exploring the holobiont concept.
• A recent article describing how the holobiont concept is involved in coral biology.
• A recent review article describing the holobiont concept.
• The life cycle of the cnidarian Cassiopia xamachana used by Dr. Medina's research group as a model system.
• A book chapter from Dr. Medina describing the use of Cassiopia xamachana as a cnidarian model system for symbiosis and holobiont studies.
• A video description of how to raise Cassiopia xamachana from a member of Dr. Medina's research group.
• An article from Dr. Medina's research group discussing the microbial community of the holobiont of coral.
• An article from Dr. Medina's research group discussing the coral-algal symbiosis.
• An article about Dr. Medina and colleagues' work on ancient coral DNA to study the holobiont concept over time.
• A video of Dr. Medina discussing her research.
• A link showing Dr. Medina's interest in the intersection between art and science.
• A link showing Dr. Medina's interest in the intersection between coral art and science.
• A very informative Wikipedia page about Dr. Medina.
• A link to Dr. Medina's research group website.
• A link to Dr. Medina's faculty website.

Intro music is by Reber Clark

Send your questions and comments to [email protected]

Matters Microbial #139: How Listeria Gets By With a Little Help From Its Friends September 23, 2026

Today Dr. Jasna Kovac, Huck Chair in Microbiomes in Food Safety and Associate Professor of Food Science at Penn State University (and active member of Penn State's One Health Microbiome Center) joins the quality quorum to discuss how understanding the microbiome in food processing facilities can help reduce the incidence of food borne illnesses, including Listeria.

Host: Mark O. Martin

Guest: Jasna Kovac

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Links for this episode

• Here is an overview of Listeria as a microbe.
• Here is an overview of Listeria pathogenesis.
• A video showing "actin rockets" moving Listeria around inside of a eukaryotic cell.
• Overview from the CDC regarding Listeria.
• Prior #MattersMicrobial podcast about Listeria by Dr. Lisa Gorski.
• An overview of microbial food safety issues.
• Description of the cantaloupe associated Listeria outbreak.
• Description of the caramel apple Listeria outbreak.
• An overview of whole genome sequencing as a diagnostic tool.
• A video description of MIC (minimal inhibitory concentration) relationship between microbes and antimicrobials.
• An overview of biofilms.
• A prior #MattersMicrobial podcast about biofilms with Dr. Matthew Fields.
• The One Health Concept linking many aspects of everyday life to microbiology.
• A description of Sanger 16S rRNA sequencing.
• An overview of MPN (most probably number) analysis in microbiology.
• A video describing the very useful LIVE/DEAD dye approach in microbiology.
• Microbiology and sanitizers.
• An overview of EPS (extracellular polysaccharides).
• Description of SNPs (single nucleotide polymorphisms).
• An overview of the lineages of Listeria.
• A description of Dr. Kovac's approach to precision food safety.
• A nice description of Dr. Kovac's evaluation of tree fruit processing plants described in this podcast.
• A wonderful video presentation by Dr. Kovac.
• Dr. Kovac's academic website.
• The research laboratory website for Dr. Kovac and colleagues.

Intro music is by Reber Clark

Send your questions and comments to [email protected]

Matters Microbial #138: Sightseeing the Microbial World September 8, 2026

Today Dr. Monika Oli, Instructional Professor of the Department of Microbiology and Cell Science at the University of Florida joins the quality quorum to discuss how she teaches microbiology students to view the topic through a global lens as a study abroad program. Her approach demonstrates how travel enriches scientific understanding, broadens cultural perspectives, and prepares students to become globally engaged microbiologists equipped to address the challenges of an interconnected world.

Host: Mark O. Martin

Guest: Monika Oli

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Links for this episode

• Here is a link to some basic history of microbiology.
• A nice biography of Antonie van Leeuwenhoek.
• A truly wonderful video about Leeuwenhoek that is SO worth your time.
• A description of the "Leeuwenhoek Microscope."
• A website that explains how you can build a replica of this famous instrument.
• An overview of the Delft school of microbiology.
• A biography of Martinus Beijerinck (an amazing microbiologist).
• The website of Micropia, the microbiology focused museum in Amsterdam.
• A fun article about the "tardigrade chair" at Micropia I discussed.
• An article about "microbial tours."
• The CEPA company that helps to create academic tours.
• An overview of experiential learning.
• The story of Ignaz Semmelweis.
• A description of the abbey where Gregor Mendel did his work with pea plants.
• A biography of Karl Stetter.
• An amazing video featuring Karl Stetter.
• The famous book, "The Little Prince," by Antoine de Saint-Exupéry which can be linked to microbiology.
• How some UNESCO Heritage sites are related to microbiology.
• The fermented food kimchi and its microbiological origin.
• The microbiology of sourdough bread.
• A video by Dr. Oli describing the ideas behind her microbial tours.
• A microbiology themed tour program by BYU.
• An ASM biography of Dr. Oli.
• The faculty website of Dr. Oli.

Intro music is by Reber Clark

Send your questions and comments to [email protected]

Matters Microbial #137: The Living Skin of Our Planet August 25, 2026

Today Dr. Estelle Couradeau, Assistant Professor in the Department of Ecosystem Science and Management and the Huck Institutes of the Life Sciences at the Pennsylvania State University, joins the quality quorum today to discuss the role that the soil microbiome can play in terms of agriculture, moderating temperature, and protecting specific environments.

Host: Mark O. Martin

Guest: Estelle Couradeau

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Links for this episode

• The Erskine Foundation fellowship website.
• An overview of Paenibacillus.
• An article discussing the fascinating colonial morphology often found with Paenbacillus.
• A blog post that demonstrates that the odd appearance of Paenibacillus can be used by other microbes for dispersal!
• Dr. Jo Handelsman's essential book, "A World Without Soil."
• A fine video describing the soil microbiome.
• The complexity of soil with regard to where and how microbes can live.
• Science journalist Carl Zimmer's indispensable essay likening the microbial ecology of lakes to the human body: "The Human Lake."
• An overview of dormancy in microbes.
• The "BonCat" (bio-orthogonal non-canonical amino acid tagging) technique for detecting living microbes in a sample without cultivation.
• An overview of flow cytometry in microbiology.
• An essay suggesting that marine bacteria are involved in the production of clouds.
• An article about climate change and microbes.
• An article about cyanobacteria and "sunscreen."
• A review article about the "biocrust" concept.
• A video overview of beautiful and fascinating microbial fossils: stromatolites.
• A video by Dr. Couradeau describing her research.
• Articles by Dr. Couradeau and colleagues asking which microbes are active in soil: here, here, and here.
• Articles by Dr. Couradeau and colleagues asking if microbes can change the temperature of a desert: here and here.
• Articles by Dr. Couradeau and colleagues that explore the hidden microbiomes of Andean páramo wetlands: here and here.
• Dr. Couradeau's faculty website.
• Dr. Couradeau's research website.

Intro music is by Reber Clark

Send your questions and comments to [email protected]

Matters Microbial #136: When Bacteria Open the Wrong Door August 11, 2026

Today Dr. Michael D.L. Johnson, Associate Professor of Immunobiology at the University of Arizona, joins the quality quorum today to discuss copper, microbiology, and a possible new strategy to fight bacteria that cause disease.

Host: Mark O. Martin

Guest: Michael D. L. Johnson

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Links for this episode

• A link to Hartiful, the Etsy artist who custom creates glow in the dark (and many other kinds) pins.
• A link to the essential science artist Beatrice the Biologist.
• A link to World Microbiome Day.
• A link to Micropia, the microbiology museum in Amsterdam.
• A recent article on the growing threat of antibiotic resistance among disease causing bacteria.
• A video demonstrating the Kirby Bauer procedure, which shows antimicrobial effects and zones of inhibition.
• A link to an earlier #MattersMicrobial episode with Dr. Michael Schmidt describing copper and microbes.
• A review article describing the impact that copper can have on microbes.
• A review article on Streptococcus pneumoniae, the organism with which Dr. Johnson works.
• An video celebrating the role that S. pneumoniae had in determining that DNA was the genetic material prior to World War 2.
• An overview of siderophores that help microbes obtain needed iron.
• An article about redox activity and copper and microbes.
• The relationship between metal toxicity and antimicrobial activity.
• The role that copper plays in agriculture.
• The differences between Gram positive and Gram negative bacteria.
• An article on efflux pumps and metal toxicity in microbes.
• An article describing how iron binding proteins also bind copper.
• An article describing how zinc interacts with microbes.
• A wonderful description of Dr. Johnson's "Trojan Horse" approach to battle disease causing microbes.
• A relevant review article by Dr. Johnson and his colleagues discussing copper and microbes.
• An overview of the "Hypothesis Fund," which supports unusual ideas in science.
• A video of Dr. Johnson describing his research.
• Dr. Johnson's faculty website.
• Dr. Johnson's research laboratory website.

Intro music is by Reber Clark

Send your questions and comments to [email protected]

Matters Microbial #135: Biofilms in Motion—The Adorable Zorbs July 30, 2026

Host: Mark O. Martin

Guest: Jo Handelsmann, Shruthi Magesh

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Links for this episode

• Here is a link to the Etsy shop where one can buy the wonderful "THIS IS WHAT A MICROBIOLOGIST LOOKS LIKE" enamel pins.
• Here is a link to the World Microbiome Day website.
• Here is a link to the interesting work of Contamination Club.
• The story of Alexander Fleming's famous contaminant that led to the discovery of penicillin.
• Here is a link to Dr. Handelsman's recent book, "A World Without Soil." Highly recommended.
• The website for Dr. Handelsman's wonderful "Tiny Earth" program, helping students worldwide to screen soil for antimicrobial production (and learning about microbial diversity).
• An overview of the microbial complexity of soil.
• A video overview of biofilms.
• A video overview of types of bacterial motility.
• A video overview of "gliding motility" among bacteria.
• Some bacteria can "hitchhike" or are carried by other bacteria, such as Paenibacillus.
• Learning about an odd sport involving "zorbs."
• An introductory essay on "zorbing" and motility.
• Another introductory essay on "co-zorbing," the topic of today's discussion.
• A description of Flavobacterium johnsoniae, which carries out "zorbing."
• The original article on THOR ("The Hitchhikers of the Rhizosphere") by Dr. Handelsman and colleagues.
• The original "zorb" paper by Dr. Handelsman and colleagues that was discussed during today's podcast.
• The "co-zorb" paper by Dr. Handelsman, Dr. Magesh, and colleagues that was discussed during today's podcast.
• A fascinating video by Dr. Handelsman and her path to becoming a microbial scientist. Highly recommended..
• Dr. Handelsman's faculty website.
• The website for the Wisconsin Institute for Discovery.
• Dr. Handelsman's research laboratory website.

Intro music is by Reber Clark

Send your questions and comments to [email protected]

Matters Microbial #134: Could Alien Life Use Different Chemistry? July 14, 2026

Today Dr. Morgan Sobol, Assistant Professor in the Department of Biology at Texas State University, joins the Quality Quorum today to discuss how microbes on early earth began interacting with elements like nitrogen, making life possible here and perhaps elsewhere in the universe! You will learn about the fundamental and amazing enzyme nitrogenase!

Host: Mark O. Martin

Guest: Morgan Sobol

Download MM134 (37 MB MP3, 62 mins)

Subscribe: Apple Podcasts, Spotify

Become a patron of Matters Microbial!

Links for this episode

• The website for ASM Microbe, the annual meeting of microbiologists.
• The "live" #MattersMicrobial session recorded at ASM Microbe, with Dr. Hannah Reich.
• An essential article about "A World Without Microbes."
• A video version of "A World Without Microbes."
• An introduction to microbial ecology.
• An overview of the enzyme that fixes carbon dioxide into organic matter, Rubisco.
• An overview of the enzyme that converts practically inert dinitrogen gas into bioavailable ammonia, nitrogenase.
• A short essay on metalloenzymes, including nitrogenase.
• An overview of nitrogen fixing microbes, and the strategies they use.
• A review editorial describing the burgeoning field of astrobiology.
• A link to a NASA program exploring early evolution of microbial life.
• An article on the microbially caused Great Oxidation Event that changed our atmosphere eons ago, making life like forms like ours possible.
• An article exploring the evolution of microbial nitrogen fixation.
• An abstract by Dr. Sobol and colleagues, discussing the evolution of nitrogen fixation in an ancient ecological context.
• A lovely article about the microbiology of Yellowstone National Park.
• Dr. Sobol's faculty website.
• Dr. Sobol's interesting research group website.

Intro music is by Reber Clark

Send your questions and comments to [email protected]

Matters Microbial #133: The Microbial Partnerships That Help Corals Survive June 29, 2026

Dr. Hannah Reich of the Department of Environmental Biology at the State University of New York's College of Environmental Science and Forestry joins the #QualityQuorum to discuss how microalgal interactions (including with bacteria) are fundamental contributors to large scale ecosystem processes including the ocean carbon pump, the duration of algal blooms, and the evolutionary success of coral reefs.

Host: Mark O. Martin

Guest: Hannah Reich

Subscribe: Apple Podcasts, Spotify

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Links for this episode

• An essay on the coral holobiont.
• A discussion of the phycosphere.
• A discussion of the rhizosphere.
• A review of the roles of iron in microbial biology.
• An overview of siderophores in the microbial world.
• An article about iron, the warming oceans, and coral.
• A VERY recent article by Dr. Reich and colleagues regarding siderophores in the coral holobiont.
• A very nice short video by Dr. Reich explaining her work at ESF.
• Dr. Reich's faculty website.
• Dr. Reich's fascinating laboratory group website.

Intro music is by Reber Clark

Send your questions and comments to [email protected]

Matters Microbial #132: What 83,000 Generations of Bacteria Reveal About Evolution June 17, 2026

Today Dr. Jeffrey Barrick, John A. Hannah Distinguished Professor of the Department of Microbiology, Genetics, & Immunology and the Department of Entomology at Michigan State University, joins the quality quorum today to discuss how microbes can be used to study evolution itself. He will also discuss the impressive and ongoing LTEE program, the experiments that originate from it, and what they tell us about evolution.

Host: Mark O. Martin

Guest: Jeffrey Barrick

Subscribe: Apple Podcasts, Spotify

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Links for this episode

• Here is a link to an article about the late great Abigail Salyers.
• Here is what I wrote about Dr. Salyers. I learned so much from her.
• An article about the contributions of Dr. Theodosius Dobzhansky to the study of evolution.
• The concept of contingency during evolution.
• An overview of microbial evolution.
• A link to "Microbes and Evolution," a book discussed during this podcast.
• A link to "A Primer for Experimental Evolution," a book discussed during this podcast.
• The concept of Growth Advantage in Stationary Phase (GASP).
• A video about the MEGA plate experiment by Dr. Michael Baym and colleagues. This is a "must watch."
• An video about Dr. Richard Lenski, originator of the LTEE.
• Dr. Lenski's website.
• The LTEE (long term evolutionary experiment) website. There is so much here to explore.
• An excellent introduction to the LTEE.
• An article about the amazing " climbing citrate mountain" innovation during LTEE described in the podcast.
• A video by Dr. Lenski about LTEE.
• A video by Dr. Barrick that is worth your time.
• Dr. Barrick's faculty website at Michigan State University.
• Dr. Barrick's research laboratory website.

Intro music is by Reber Clark

Send your questions and comments to [email protected]