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

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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

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