Nice to see a follow up story on @drlauranolan.bsky.social Pseudomonas aeruginosa T6SS toxin Tse8

Our latest efforts to understand Enterococcal wound infection. In long-term collaboration with @gthibault.bsky.social, we discovered how E. faecalis makes extracellular ROS - via EET!⚡️Which in turn dysregulates host UPR to delay wound healing. Led by @aarontan.bsky.social - his videos below are 🤩!

Genevieve is retiring and that will leave a big gap at the CNRS in Marseille. Some of the past members of the lab celebrated the event. Enjoy a deserved relaxing time.

A bit late but it has been a fantastic ETOX25 conference organized by @pbernalt6ss.bsky.social and @davidalbesa.bsky.social A fantastic opportunity for @casandratan.bsky.social from @fillouxlab.bsky.social to attend and to reunite a whole crew of Imperial College London Alumni.

Escherichia coli with a 57-codon genetic code The near-universal genetic code uses 64 codons to encode the 20 canonical amino acids and protein synthesis. Here we designed and generated Escherichia coli with a 4 Mb synthetic genome in which we re...

Escherichia coli with a 57-codon genetic code | Science www.science.org/doi/10.1126/...

Functional replacement of ancestral antibacterial secretion system in a bacterial plant pathogen Nature Ecology & Evolution - The bacterial plant pathogen genus Xanthomonas uses two distinct secretion systems for antibacterial competition. Here the authors show that some Xanthomonas...

Plant pathogen bacterium replaced its ancestral antibacterial secretion system with a new functional one, revealing bacterial adaptability.
This work highlights evolutionary innovation in microbial competition, crucial for understanding pathogen survival and plant disease dynamics.
rdcu.be/eyz8W

On the biological meaning of the population pangenome The prokaryotic pangenome, the full complement of genes within a species, is strikingly large. To understand how ecological forces shape this diversity, it is useful to examine the variable gene pool within a single population, defined as cells of the same species coexisting in the same time and place. This single-population pangenome reflects the minimal flexible gene repertoire required in a specific environmental context. Recent long-read metagenomic studies of marine prokaryotes show that local population pangenomes remain large, often comprising thousands of genes. Specifically, cells belonging to the same species of the streamlined alfaproteobacterium Pelagibacter, coming from the same sampling site and even sample, contain more than a thousand genes. Many of these genes are related variants that collectively expand the population’s metabolic potential, akin to paralogs within a single large genome. We propose for them the name 'metaparalogs' together with the idea that these data reflect cooperative, population-level strategies, where the flexible genome operates as a public good (sensu Samuelson), enhancing both adaptability and ecological resilience. A role for extracellular vesicles in facilitating resource sharing is also suggested.

On the biological meaning of the population pangenome: Trends in Microbiology https://www.cell.com/trends/microbiology/fulltext/S0966-842X(25)00216-1?rss=yes&utm_source=dlvr.it&utm_medium=twitter

electron microscopy image of a C elegans on a yellow background

🧬June's most-read Genetics paper independently validates previous research showing that #CElegans can inherit learned pathogen avoidance: buff.ly/HQgprLp

Figure 2. Contact-dependent predation relies on specific adaptations of the predator cell envelope. (a) Envelope-spanning multiprotein machineries, including type IV pili (T4P, in shades of pink) and secretion systems (shades of brown and orange), participate in various predatory mechanisms. For clarity, subcomplexes (such as the OM secretin of T4P) are represented as single objects rather than complex oligomeric assemblies; for further details about molecular composition, structural architecture, and annotations of these systems, we refer the reader to Refs. 14••, 42••, 43 (Kil and Tad systems), 39, 44 (T4aP), 35, 45 (T4aSS), 30••, 46 (T9SS and grappling hook), 30••, 47 (T6SS), and 32, 15••, 42••, 48 (T3SS*). (i) Tight adherence (Tad) and type IVa (T4a) pili located at the prey-contacting cell pole are essential for B. bacteriovorus predation, but their precise function is unclear. (ii) L. enzymogenes contact-dependent killing of prey involves a type IVa secretion system (T4aSS), hypothesised to deliver toxic effectors into prey cells. (iii) In liquid environments, prey capture by Aureispira sp. CCB-QB1 depends on grappling hooks consisting of a GhpA heptamer, a T9SS substrate. Subsequent prey killing and lysis is proposed to rely on the contraction of an unusual T6SS harbouring antenna-like structures of unknown function. (iv) M. xanthus prey killing and lysis are mediated by the interplay of a Tad-like system, termed the Kil system, and a needle-less type III secretion system complex (T3SS*, lacking components usually required for toxic effectors delivery). Both systems localise at prey contact sites and are hypothesised to form a complex for the delivery of toxic effectors into prey cells via specialised Tips located at the extremity of the Kil pilus. (b) During epibiotic predation, B. exovorus uses its nonflagellated pole to form a stable junction with the prey OM. (i) Representative Cryo-EM image showing B. exovorus attached to the C. crescentus prey surface (…

Figure 1. Contact-dependent predation strategies among bacteria. (a–d) Physical contacts between predator (light blue) and prey (dark grey) cells are highlighted with orange halos. A characterised prey–predator pair was selected to illustrate each predation strategy. All represented prey cells are diderm bacteria; the periplasm is indicated when relevant. Plain arrows indicate transitions between key predation steps. Dashed arrows represent active cell movement. Indicative scale bars are included on each panel. (a) Epibiotic predation. Bdellovibrio exovorus firmly attaches to the surface of prey, including Caulobacterales species (Caulobacter crescentus is depicted here) and consumes their contents from outside (prey shown in pale grey). (b) Endobiotic predation. Upon contact with a broad range of proteobacteria, such as Escherichia coli, Bdellovibrio bacteriovorus transiently attaches to the prey surface before invading its periplasm and digesting the prey from inside. (c) Ixotrophy. Multicellular filaments of Aureispira sp. CCB-QB1 capture, immobilise, and lyse their prey, which include Vibrio (e.g. Vibrio campbellii) and Cyanobacteria species. (d) Group attack. Myxococcus xanthus uses social motility to efficiently invade prey colonies (e.g. E. coli). M. xanthus kill and lyse prey cells in a contact-dependent manner. M. xanthus can also prey on monoderm species, but efficient prey lysis requires bacteriolytic factors secreted in the environment in addition to direct contact 14••, 15••, 16. (c,d) Prey lysis upon contact is depicted with dashed lines.

a compendium of vampires and pirates
(and their armories). actually more of an encyclopedia...

by @coralietesseur.bsky.social (drawings made by hand!⭐), @ysantin.bsky.social & @lalouxlab.bsky.social

read! > www.sciencedirect.com/science/arti...
#MicroSky

1/16 New pre-print from the Sternberg Lab!
We uncover how temperate phages can use RNA-guided transcription factors to remodel the flagellar composition of their bacterial host and enhance their fitness.
Find the preprint and full story here: tinyurl.com/mshwjd77

Systematic, high-throughput characterization of bacteriophage gene essentiality on diverse hosts Chen et al. report PhageMaP, a high-throughput approach to generate and characterize genome-wide loss-of-function phage libraries. PhageMaP systematically interrogates conditional gene essentiality, p...

Characterizing phage gene essentiality with PhageMaP:

• High-throughput approach to generate genome-wide loss-of-function phage libraries.
• Interrogates gene essentiality w/insights into phage genome organization, host antiviral defense & gene function
www.cell.com/cell-host-mi...

Screenshot of Dor's link to his PNAS paper, preview image is a hissing snake's head

Note to @fillouxlab.bsky.social lose the molecular structure slides, more snake analogies to describe T6SS!

A massive thank you to all the incredible participants and speakers who made ETOX 2025 in the Basque Country an unforgettable event! Your insights, discussions, and passion for bacterial protein toxins have truly advanced the field. We're already looking forward to next time! #ETOX2025

@pbernalt6ss.bsky.social and @davidalbesa.bsky.social opening #ETOX2025. Looking forward to some hot science in the next couple of days.

How a Biofilm’s Strange Shape Emerges From Cellular Geometry | Quanta Magazine Micro decisions can have macro consequences. A soft matter physicist reveals how interactions within simple cellular collectives can lead to emergent physical traits.

Reading:

How a Biofilm’s Strange Shape Emerges From Cellular Geometry www.quantamagazine.org/how-a-biofil... via @QuantaMagazine

I'm pleased to announce that I will be starting my lab as an Assistant Professor at UMass Chan Medical School in August! My group will study phages that infect corynebacteria and mycobacteria to understand bacterial cell envelope assembly and phage gene function. Website and more info to come soon!

A get-together of Dartmouth folks at ASM Microbe!
#ASMicrobe

New in JB: Oladosu and Sauer show that FleQ, SagS and BrlR contribute to fine tuning the expression of genes contributing to antibiotic tolerance in P. aeruginosa biofilms.
journals.asm.org/doi/10.1128/...
@asm.org #JBacteriology

The Power Duo: How the Interplay Between Nucleoid‐Associated Proteins and Small Noncoding RNAs Orchestrates the Cellular Regulatory Symphony Nucleoid-associated proteins play a crucial role in the compaction of bacterial DNA and the regulation of gene expression. The emergence of small noncoding RNAs as regulatory elements in these proces...

Molecular Microbiology | Microbiology Journal | Wiley Online Library onlinelibrary.wiley.com/doi/10.1111/...

𝔟α𝐜𝐓𝕖Ř𝒾ⒶĹ ＳＨⓐ𝓹Ẹ 丂ħ𝓲ƒ𝓉ⒺⓇร 🦠

Ultra-sensitive RNA-seq and FISH show 𝘉𝘢𝘤𝘵𝘦𝘳𝘰𝘪𝘥𝘦𝘴 𝘵𝘩𝘦𝘵𝘢𝘪𝘰𝘵𝘢𝘰𝘮𝘪𝘤𝘳𝘰𝘯 cells adopt different shapes reflecting distinct gene expression profiles and metabolic specializations

A deliberate survival strategy for the ever-changing gut environment?

www.cell.com/cell-reports...

Flipping the magic switch to persistence via GTP depletion - Nature Microbiology Different forms of bacterial persistence in Bacillus subtilis are driven by a common (p)ppGpp-mediated switch that depletes GTP, triggering a rapid transition from a sensitive to an antibiotic-recalci...

🚨Out now!

#News&Views

Different forms of bacterial persistence in Bacillus subtilis are driven by a common (p)ppGpp-mediated switch that depletes GTP, triggering a rapid transition from a sensitive to an antibiotic-recalcitrant state.

#MicroSky

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

This is figure 2, which shows a genome-wide map of the Shigella geneset required to invade the human enteroid infection model.

A study in Nature Genetics establishes the comprehensive genome-wide map of Shigella genes required to infect human intestinal epithelium. go.nature.com/4e7fdKp 🧬 🧪

A copper shield The bacteria responsible for tuberculosis use a system that imports copper to help defend themselves against the immune system.

The bacteria responsible for tuberculosis use a system that imports copper to help defend themselves against the immune system.

Trade-off between resistance and persistence in high cell density cultures
doi.org/10.1128/msys...

Unveiling the structural spectrum of SARS-CoV-2 fusion by in situ cryo-ET - Nature Communications This study delineates the full sequence of SARS-CoV-2 spike-mediated membrane fusion and shows how S2-targeting antibodies inhibit this process, using a near-native functional fusion system and cryo-e...

"Unveiling the structural spectrum of SARS-CoV-2 fusion by in situ cryo-ET"

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

Out this weekend in @ismepublications.bsky.social

We looked at 10,000 species to map the diversity and history of the bacterial #flagellar motor across the tree of life.

Lots of (re)analysis , especially from Jamiema Sara Philip @unswbabs.bsky.social

academic.oup.com/ismej/advanc...

Diagrams of Borrelia burgdorferi flagella, adapted from https://www.nature.com/articles/nrmicro1086

Regulation of the main structural element of Lyme spirochete flagella

"The Flagellin-specific chaperone FliS of Borrelia burgdorferi controls the cytoplasmic pool of Flagellins at the level of translation initiation, secretion, and proteolysis"
pubmed.ncbi.nlm.nih.gov/40491023/

#MicroSky

Left: Schematical overview of the PelBC structure, the charge distribution and the key protein:protein and protein:lipid interactions resolved in the study. Right: The putative route of the substrate, Pel exopolysaccharide (yellow), across the tunneled conformation of the PelBC export complex. The polysaccharide composed of GalNAc is partially de-acetylated by PelA while bound to the helical scaffold of PelB, and the transport is facilitated by electrostatic interactions with the anionic interior of the PelB β-barrel. The polysaccharide uses the exit tunnel formed upon Plug-S displacement, while being screened by the conserved Tyr-1103 residue.

Fig. 9.
caption see ALT

Assembly and the gating mechanism of the Pel exopolysaccharide export complex PelBC of Pseudomonas aeruginosa - Nature Communications The pathogen Pseudomonas aeruginosa uses a membrane complex, PelBC, to produce exopolysaccharides for biofilm formation. Here the authors combine structural analysis, simulations and single-channel re...

biofilm aficionados take note 👇
#MicroSky #CryoEM

doi.org/10.1038/s414...

Bacteria poison and eat their neighbors Bacteria leverage a secretion system to kill and scavenge nutrients from nearby competitors

Bacteria poison and eat their neighbors | Science www.science.org/doi/10.1126/...