Mizrahi Lab

With a lot of appreciation to the @erc.europa.eu , @dfg.de , Israel Science Foundation, @snsf.ch & Novartis Foundation for their support, which made this study possible. (12/12)

Huge thanks to the incredible team and collaborators: Dr. Anke Trautwein-Schult, Sarah Moraïs, @bwmr.net , Dörte Becher, Ohad Medalia, Omar Tovar, Ed Bayer, Itai Amit, Meltem Tatli, Sebastian Simoni, Liron Levin. (11/12)

By understanding the molecular mechanics of R. bromii, we can design better nutritional guidelines and probiotics. If we know how to support the "key" unlocking the fiber, we can improve gut health, metabolism, and inflammation for the host. (10/12)

By understanding the molecular mechanics of R. bromii, we can design better nutritional guidelines and probiotics. If we know how to support the "key" unlocking the fiber, we can improve gut health, metabolism, and inflammation for the host. (9/12)

We found that two specific enzymes, Amy4 and Amy16, are the key. By design, they are positioned next to each other. This deliberate positioning dramatically boosts their overall function and the microbe’s ability to break down resistant starch. (8/12)

R. bromii also adapts itself to what we eat. Our proteomics data shows that when RS is abundant, the bacterium dramatically shifts the composition of the amylosome, pumping out specific enzymes needed for the job. (7/12)

We solved the structures of the main enzymes in the amylosome. This allowed us to look at them from extremely close-up, down to the atomic level, and understand how each enzyme works and how their shapes, positions, and interactions help the bacterium break down resistant starch efficiently. (6/12)

For the first time, we visualized the amylosome in situ! Cryo-ET revealed it as a dense, stable protein layer anchored to the cell wall, physically reaching out to contact and degrade the starch granules. (5/12)

The ability lies in the Amylosome. We knew this enzyme complex existed on the bacterial cell surface, but its precise architecture and composition were not resolved before. We combined Cryo-ET, proteomics, and structural biology to see R. bromii from the micrometer down to the nanometer scale.(4/12)

Ruminococcus bromii, is the "Keystone Species" for resistant starch degradation. It initiates the breakdown of RS, releasing energy that feeds the rest of the beneficial bacteria in our gut. But how does it dismantle such tough granules? (3/12)

Dietary fiber is essential for our gut wellfare, yet we can’t digest to its full extend ourselves. Specifically, Resistant Starch (RS), found in potatoes 🥔, green bananas 🍌, and whole grains, is a beneficial source for our well-being. but brake it is a complex job (2/12)

In our new paper in @natcomms.nature.com We discovered how Ruminococcus bromil organizes and regulates its enzyme complex to efficiently break down resistant starch, forming a key metabolic foundation for the human gut ecosystem. (1/12)

📄 www.nature.com/articles/s41...

With a lot of appreciation to the @erc.europa.eu , @dfg.de , Israel Science Foundation, @snsf.ch & Novartis Foundation for their support, which made this study possible. (12/12)

Huge thanks to the incredible team and collaborators: Dr. Anke Trautwein-Schult, Sarah Moraïs, @bwmr.net, Dörte Becher, Ohad Medalia, Omar Tovar, Ed Bayer, Itai Amit, Meltem Tatli, Sebastian Simoni, Liron Levin. (11/12)

By understanding the molecular mechanics of R. bromii, we can design better nutritional guidelines and probiotics. If we know how to support the "key" unlocking the fiber, we can improve gut health, metabolism, and inflammation for the host. (10/12)

We discovered that the amylosome uses Spatial Constraints to force synergy. Amy4 acts as a scaffold. Amy16 connects to it like a specific LEGO brick . This "lock and key" mechanism ensures they are always positioned side-by-side for maximum degradation efficiency. (9/12)

We found that two specific enzymes, Amy4 and Amy16, are the key. Alone, they are okay. Together? They are a powerhouse. But they don't just float around randomly. (8/12)

R. bromii also adapts itself to what we eat. Our proteomics data shows that when RS is abundant, the bacterium dramatically shifts the composition of the amylosome, pumping out specific enzymes needed for the job. (7/12)

We solved the structures of the main enzymes in the amylosome. This allowed us to look at them from extremely close-up, down to the atomic level, and understand how each enzyme works and how their shapes, positions, and interactions help the bacterium break down resistant starch efficiently. (6/12)

For the first time, we visualized the amylosome in situ! Cryo-ET revealed it as a dense, stable protein layer anchored to the cell wall, physically reaching out to contact and degrade the starch granules. (5/12)

The ability lies in the Amylosome. We knew this enzyme complex existed on the bacterial cell surface, but its precise architecture and composition were not resolved before. We combined Cryo-ET, proteomics, and structural biology to see R. bromii from the micrometer down to the nanometer scale.(4/12)

Ruminococcus bromii, is the "Keystone Species" for resistant starch degradation. It initiates the breakdown of RS, releasing energy that feeds the rest of the beneficial bacteria in our gut. But how does it dismantle such tough granules? (3/12)

Dietary fiber is essential for our gut wellfare, yet we can’t digest to its full extend ourselves. Specifically, Resistant Starch (RS), found in potatoes 🥔, green bananas 🍌, and whole grains, is a beneficial source for our well-being. but brake it is a complex job. (2/12)

Ruth, thank you so much for your support.

A glimpse into the role of auxiliary metabolic genes in cyanophages during infection

Our BEHIND THE STORY. A glimpse into the role of auxiliary metabolic genes in cyanophages during infection communities.springernature.com/posts/a-glim...

Occurrence and temporal dynamics of denitrifying protist endosymbionts in the wastewater microbiome Abstract. Effective wastewater treatment is of critical importance for preserving public health and protecting natural environments. Key processes in waste

Protist–bacteria partnerships are more common in wastewater treatment plants than we thought. In this ISME communications paper, we uncovered widespread denitrifying endosymbionts inside ciliates, their global distribution, and their temporal dynamics across WWTPs.🦠
academic.oup.com/ismecommun/a...

Picture of a metabolic pathway map

1/3 We're hiring! Join us as a PhD student in metabolic microbiome modeling within @spp2474.bsky.social — help uncover the microbiome’s dark matter alongside top microbiome labs across Germany! @uni-kiel.de
jobs.uksh.de/job/Kiel-PhD...

Very cool stuff from the the @mizrahilab.bsky.social!

Thank you very much Jonathan!

Really fascinating and important work