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John Helmann

@johnhelmann

Professor at Cornell Univ. Bacillus subtilis physiology and stress responses (metal homeostasis, redox stress, antibiotic resistance & cell envelope). EIC of Mol Microbiol.

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17.10.2023
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Latest posts by John Helmann @johnhelmann

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Convergent MurJ flippase inhibition by phage lysis proteins - Nature A common mechanism of inhibition of the essential lipid II flippase MurJ by three distinct phage-encoded single-gene lysis proteins provides insights into potential new targets for antimicrobial devel...

Convergent MurJ flippase inhibition by phage lysis proteins www.nature.com/articles/s41...

25.02.2026 19:01 πŸ‘ 30 πŸ” 12 πŸ’¬ 0 πŸ“Œ 0
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See our newest manuscript dissecting emergent functions in a multispecies biofilm (metabolite cross-feeding, siderophore induction and cross-species utilization) that translates to plant growth promotion
Great work by @jiyuxie.bsky.social and Xinli Sun
www.biorxiv.org/content/10.6...

25.02.2026 10:08 πŸ‘ 27 πŸ” 8 πŸ’¬ 2 πŸ“Œ 2
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Oxygen metabolism in descendants of the archaeal-eukaryotic ancestor - Nature Sequencing of marine sediments finds 136 newly identified Heimdallarchaeia and several novel lineages, and indicates that Heimdallarchaeia evolved distinct metabolic capabilities from other Asgar...

At long last! Check out the link to our publication in @nature.com to learn more. doi.org/10.1038/s415...
12/12

18.02.2026 16:12 πŸ‘ 22 πŸ” 9 πŸ’¬ 1 πŸ“Œ 1

Thank you for highlighting our paper on how septal PG hydrolysis licenses a second wave of PG transpeptidation during cell separation! www.nature.com/articles/s41.... I will do a thread when the page set version is out.

18.02.2026 18:49 πŸ‘ 21 πŸ” 7 πŸ’¬ 2 πŸ“Œ 1
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Bidirectional promoters in Escherichia coli: regulatory rules and implications for gene expression noise Abstract. In prokaryotes, bidirectional promoters are pseudo-symmetrical DNA sequences that stimulate divergent transcription. Ubiquitous, and far more lik

@ewarman.bsky.social has followed up on her discovery of bidirectional promoters in bacteria by defining their basic rules for regulation and links to gene expression noise...

academic.oup.com/nar/article/...

06.02.2026 15:35 πŸ‘ 21 πŸ” 13 πŸ’¬ 0 πŸ“Œ 0
Cartoon representing the mycobacterial oxidative phosphorylation system, including cytochromes, NDH-2, and ATP synthase. Taken from Figure 1 of the article.

Cartoon representing the mycobacterial oxidative phosphorylation system, including cytochromes, NDH-2, and ATP synthase. Taken from Figure 1 of the article.

#Microbiology

The anti-tuberculosis drug bedaquiline targets the mycobacterial ATP synthase, but how that leads to bacterial death is unclear

Here the authors clarify how bedaquiline works

@jnblab.bsky.social @morwan.me
#TBSky #antibiotics #AMR

http://dlvr.it/TQjZ0W

02.02.2026 17:07 πŸ‘ 36 πŸ” 20 πŸ’¬ 3 πŸ“Œ 0
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Bacteriocin biophysics: From protein-protein interaction models to navigators of the bacterial cell envelope Bacteriocins are toxins deployed by bacteria to kill their competitors. Here, I reflect on my laboratory’s work on protein bacteriocins and their immunity proteins from Gram-negative bacteria. We unco...

A gift of an article from the inimitable Colin Kleanthous as he says a moving farewell to his laboratory. A brave, unrepentant and scientifically brilliant journey is described - please have a read, friends.

www.jbc.org/article/S002...

02.02.2026 12:39 πŸ‘ 68 πŸ” 32 πŸ’¬ 3 πŸ“Œ 1
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Microbial Primer: Ancientbiotics – making modern antimicrobials from historical infection remedies The modern antibiotic era began in the early twentieth century, but humans have long used materials from the natural world to attempt to treat the symptoms of infection. In this primer, we will discus...

Why should microbiologists be interested in historical infection remedies, and how can we best investigate them for antimicrobial discovery? Thoroughly enjoyed co-writing this Microbiology Primer with @tosinorababa.bsky.social www.microbiologyresearch.org/content/jour... #MicroSky #Ancientbiotics

29.01.2026 10:44 πŸ‘ 24 πŸ” 13 πŸ’¬ 3 πŸ“Œ 2
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PlanktoScope Open and frugal modular imaging platform for citizen oceanography

www.planktoscope.org

28.01.2026 20:14 πŸ‘ 6 πŸ” 2 πŸ’¬ 1 πŸ“Œ 0

CuiT is a Cu importer required for metal homeostasis in Salmonella enterica https://www.biorxiv.org/content/10.64898/2026.01.22.701185v1

23.01.2026 10:17 πŸ‘ 3 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
PNAS Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...

Congrats @regolab.bsky.social! www.pnas.org/doi/10.1073/...

17.01.2026 19:08 πŸ‘ 8 πŸ” 4 πŸ’¬ 1 πŸ“Œ 0

Regulatory divergence and functional diversification of a c-di-GMP-controlled sigma factor in Actinomycetota https://www.biorxiv.org/content/10.64898/2026.01.14.699351v1

15.01.2026 02:17 πŸ‘ 4 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
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The Bacillus subtilis class A penicillin-binding protein 4 (PBP4) requires an accessory protein RpdA Peptidoglycan (PG) synthesis is essential to maintain cell integrity during bacterial growth and division. In Bacillus subtilis, PG synthesis involves class A PBPs that act independently and class B P...

The Bacillus subtilis class A penicillin-binding protein 4 (PBP4) requires an accessory protein RpdA www.biorxiv.org/content/10.6...

12.01.2026 14:22 πŸ‘ 7 πŸ” 4 πŸ’¬ 0 πŸ“Œ 1
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A mechanotransduction mechanism for antibiotic defense in Gram-positive bacteria In this issue of Structure, Yu et al. show that the Bacillus subtilis ytr operon encodes two distinct ABC transporters. The authors present the cryo-EM structures of YtrEF in the apo and ADP-vanadate-...

🫴 A mechanotransduction mechanism for antibiotic defense in Gram-positive bacteria (Bacillus subtilis, with some interesting suppressor mutants):

In

Structure www.cell.com/structure/fu...

#subtiWiki #subtilis

11.01.2026 13:55 πŸ‘ 7 πŸ” 1 πŸ’¬ 1 πŸ“Œ 1
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Membrane editing with proximity labeling reveals regulators of lipid homeostasis - Nature Chemical Biology Coupling an optogenetic lipid-modifying enzyme with proximity labeling reveals protein networks and mechanisms regulating lipid homeostasis in the membranes of target organelles.

Thrilled to share our latest study, led by @reikatei.bsky.social, in @natchembio.nature.com! We began by asking a simple questionβ€”how do cells know if they have too much of a lipid in a particular membrane, and how do they respond to rectify this imbalance?
www.nature.com/articles/s41...
More info πŸ‘‡

07.01.2026 14:59 πŸ‘ 156 πŸ” 61 πŸ’¬ 7 πŸ“Œ 7
2026 Microbial Stress Response Conference GRC The 2026 Gordon Research Conference on Microbial Stress Response will be held in South Hadley, Massachusetts. Apply today to reserve your spot.

Registration is open for the 2026 Gordon Research Conference on Microbial Stress Response to be held on July 19-24 2026!! Submit your abstract by February 15th to be considered for a short talk. Apply now before it fills up!! Hope to see you there!! www.grc.org/microbial-st...

06.01.2026 19:15 πŸ‘ 24 πŸ” 23 πŸ’¬ 0 πŸ“Œ 2
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The Taste of Carbonation The enzyme carbonic anhydrase mediates the taste sensation of carbonated drinks.

πŸ§ͺHAPPY 2026 EVERYONE!!!! πŸ₯‚πŸΎπŸ₯³

When you enjoy your bubbly this evening, do spare a thought about carbonic anhydrase - it's an amazing enzyme (almost as fast as 2025 felt! 😜), and it turns out, it's also responsible for tasting CO2's "fizziness"!!! 🍾

www.science.org/doi/10.1126/...

31.12.2025 12:56 πŸ‘ 13 πŸ” 4 πŸ’¬ 0 πŸ“Œ 0

This work was also our first time doing membrane localization (way to go Cassidy)! And so proud of Bella’s gorgeous Paenibacillus tree showing the distribution of the transmembrane containing Spo0B! Also it’s the lab’s first paper without ribosomes 🫨, but don’t worry - the ribosomes made the Spo0B!

30.12.2025 14:01 πŸ‘ 28 πŸ” 7 πŸ’¬ 1 πŸ“Œ 0
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The Mannose Phosphotransferase System in Enterococcus lactis Is Essential for Gastrointestinal Colonization Enterococcus lactis, a recently established species that was previously classified as Enterococcus faecium clade B. Given its recent taxonomic classification, studies on this bacterium are scarce, an...

Interesting new paper on Enterococcus lactis (the species formerly known as Clade B E. faecium)

'The Mannose Phosphotransferase System in Enterococcus lactis Is Essential for Gastrointestinal Colonization'

onlinelibrary.wiley.com/doi/abs/10.1...

27.12.2025 11:48 πŸ‘ 15 πŸ” 10 πŸ’¬ 0 πŸ“Œ 0
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Predicting drug inactivation by changes in bacterial growth dynamics - npj Antimicrobials and Resistance npj Antimicrobials and Resistance - Predicting drug inactivation by changes in bacterial growth dynamics

Our recent paper in npj Antimicrobials and Resistance is a great example of scientific serendipity: after staring at thousands of bacterial growth curves over many studies, we started wondering whether the curve shapes themselves carry mechanistic information 1/9 🦠πŸ§ͺ
www.nature.com/articles/s44...

22.12.2025 15:25 πŸ‘ 48 πŸ” 26 πŸ’¬ 2 πŸ“Œ 2
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Mycobacterium tuberculosis overcomes phosphate starvation by extensively remodelling its lipidome with phosphorus-free lipids - Nature Communications Here, the authors show that Mycobacterium tuberculosis manipulates lipid metabolism to overcome host restriction, by remodelling its lipidome and utilising host lipids as an alternative phosphate sour...

We’re excited to share our latest study that reshapes our understanding of Mycobacterium tuberculosis (Mtb) lipid composition, with major implications for drug discovery, immunity, and vaccine development.

www.nature.com/articles/s41...

A thread.

22.12.2025 13:11 πŸ‘ 95 πŸ” 30 πŸ’¬ 14 πŸ“Œ 3
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The FsrA‐Mediated Iron‐Sparing Response Regulates the Biosynthesis of the Epipeptide EPE in Bacillus subtilis Under iron-limited conditions, FsrA base-pairs with the intergenic region between epeX and epeE, enhancing epeE translation and triggering EPE production. Toxin-mediated cell lysis releases nutrients....

The FsrA-Mediated Iron-Sparing Response Regulates the Biosynthesis of the Epipeptide EPE in Bacillus subtilis

#MolMicrobiol by Sarah Miercke, Rabea Ghandour, Kai Papenfort and Thorsten Mascher

onlinelibrary.wiley.com/doi/10.1111/...

18.12.2025 11:54 πŸ‘ 4 πŸ” 2 πŸ’¬ 0 πŸ“Œ 1
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Contribution of the Bacillus subtilis ytrGABCDEF operon to antibiotic stress adaptation | Microbiology Spectrum The Bacillus subtilis ytrGABCDEF operon is a reliable and specific marker for the inhibition of cell wall biosynthesis by antibiotics. It has therefore advanced as a common reporter in transcriptomic,...

Contribution of the Bacillus subtilis ytrGABCDEF operon to antibiotic stress adaptation

Microbiology Spectrum from from Michaela Wenzel at Chalmer University of Technology, Gothenburg

journals.asm.org/doi/10.1128/...

06.12.2025 20:34 πŸ‘ 1 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0
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Spx inhibits expression of the SwrAβ€’DegU master flagellar activator in Bacillus subtilis | Journal of Bacteriology Bacterial flagella are elaborate machines that are inserted through the bacterial cell envelope. The regulation of flagellar gene expression is organized in hierarchical tiers that largely correlate w...

Spx inhibits expression of the SwrAβ€’DegU master flagellar activator in Bacillus subtilis

-in JBacteriol

journals.asm.org/doi/10.1128/...

06.12.2025 20:36 πŸ‘ 8 πŸ” 5 πŸ’¬ 0 πŸ“Œ 0
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The molecular basis of the synergistic toxicity of nickel and copper, common environmental co-contaminants | Applied and Environmental Microbiology Many environments are contaminated by metals. These metals are toxic to the microorganisms that inhabit these environments and carry out important ecosystem services. While much is known about bacteri...

journals.asm.org/doi/10.1128/...

We have a new paper out, led by my PhD student Linda! Ni and Cu are common co-occurring contaminants. They are also synergistic in their toxicity. We examined the mechanisms of this synergism, finding that sulfur assimilation and Fe-S cluster biogenesis are targets.

24.11.2025 13:24 πŸ‘ 8 πŸ” 4 πŸ’¬ 0 πŸ“Œ 0
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Structural analysis of a Gram-positive type VII ABC transporter induced by cell wall-targeting antibiotics Bacteria utilize a variety of mechanisms to remodel the cell wall in response to environmental and antimicrobial stress. In the model organism Bacillu…

Cool new paper on the structure and possible function of the type VII ABC transporter YtrEF in cell wall remodeling in Bacillus subtilis!
#SubtiWiki

www.sciencedirect.com/science/arti...

29.10.2025 15:28 πŸ‘ 9 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
The Fine Structure of the Gene on JSTOR Seymour Benzer, The Fine Structure of the Gene, Scientific American, Vol. 206, No. 1 (January 1962), pp. 70-87

For those interested in further reading, the studies establishing the triplet nature of the genetic code were also reviewed by both Benzer and Crick in two 1962 Scientific American articles -- both worth a read!
www.jstor.org/stable/24937...
www.jstor.org/stable/24936...

12.09.2025 17:50 πŸ‘ 3 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0
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See our @natmicrobiol.nature.com News&Views on the publication from Yun Chen laboratory

A rapid writing exercise for MarΓ­a Negre RodrΓ­guez, a PhD student in my group

Ecological function of phenazine in soil
www.nature.com/articles/s41...

#MicrobiomeEcology at #LeidenBiology

12.09.2025 09:42 πŸ‘ 16 πŸ” 5 πŸ’¬ 2 πŸ“Œ 0

🚨 New Preprint Alert 🚨

Our latest work, A Zur-dependent regulatory RNA involved in maintaining zinc homeostasis in Staphylococcus aureus, is now live on bioRxiv! πŸ§¬πŸ¦ πŸ“„

Check it out here: www.biorxiv.org/content/10.1...

24.08.2025 06:38 πŸ‘ 13 πŸ” 12 πŸ’¬ 4 πŸ“Œ 0
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Monitoring single cell bioenergetic status and cell lysis in dense and differentiating Bacillus subtilis cultures Bacillus subtilis is a major model organism for studying population heterogeneity in clonal bacterial cultures due to its high genetic tractability and ability to differentiate into subpopulations wit...

A new methods paper from us, this time with a focus on reliable monitoring membrane potential and cell lysis at different growth stages and cell densities. Also, note the surprisingly high level of background lysis in seemingly healthy B. subtilis cultures.
www.biorxiv.org/content/10.1...

22.08.2025 07:24 πŸ‘ 31 πŸ” 13 πŸ’¬ 1 πŸ“Œ 1