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Dan Richards

@dan-m-richards.bsky.social
14 followers 47 following 5 posts

PhD candidate specializing in mass spectrometry based proteomics

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Dan Richards @dan-m-richards.bsky.social · 16/04/2026
Using rhythmic intestinal calcium waves as a reporter for defecation, Jeremy and Mark found that wild-type worms on PHB-producing bacteria (75 mM lactate) show highly abnormal and heterogeneous defects in the defecation motor program — and this is largely improved in nuc-1 mutants!
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Dan Richards @dan-m-richards.bsky.social · 16/04/2026
The phenotypes are striking. L1s are arrested by pharyngeal blockage and adult worms show a pronounced deformed anal region (Dar) 🫢 phenotype. Thanks to Jeremy Florman, Mark Alkema and their cool calcium imaging tools, we were able to systematically quantify these PHB associated phenotypes.
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Dan Richards @dan-m-richards.bsky.social · 16/04/2026
To get at the host side, a forward genetic screen shows mutations to nuc-1, homolog of mammalian DNASE2, rescues PHB toxicity. How does removal of a nuclease blocks PHB toxicity? It's an open question, but our EM images nicely show nuc-1 mutant animals accumulate less PHB in their intestine.
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Dan Richards @dan-m-richards.bsky.social · 16/04/2026
Importantly this requires live bacteria, worms fed dead bacteria or purified PHB develop normally. PHB synthesis is both necessary and sufficient for killing. Mutations to the PHB biosynthetic pathway inhibits toxicity and expressing PHB synthesis genes in E. coli is enough to make it toxic.
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Dan Richards @dan-m-richards.bsky.social · 16/04/2026
Normally non-toxic bacteria, when induced to produce the bioplastic PHB, kill C. elegans! PHB has been in the microbiology text books for over a century — in this new study I co-authored with Gabrielle Giese in the Walhout lab we show this bioplastic is also relevant for host-microbe interactions!
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Reposted by Dan Richards
Nathan Rohde @pacnorthimages.bsky.social · 17/03/2026
🪶 Anna’s Hummingbird 🎨 Full Color - Southern Oregon - Pacific Northwest #hummingbird #naturephotography #birdphotography #birding #birdsofbsky
Anna’s Hummingbird in full color
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Reposted by Dan Richards
Institut Pasteur | 130 years of biomedical research @pasteur.fr · 17/03/2025
Research led by Yasmine Belkaid & her team shows that the maternal immune system plays a key role in lactation. Unconventional T cells help develop mammary glands & promote milk production—essential for newborn health. 🔗 Read more: www.pasteur.fr/en/research-...
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