Podcasts about quorum sensing

Could the health of your skin be one of the best predictors of chronic disease risk and mortality?    In today's episode of The Longevity Podcast, Kiran Krishnan and I discuss how aging and dysfunction of skin, driven by changes in the skin microbiome, may actually precede and contribute to unhealthiness in the body, rather than simply reflecting it. Maintaining your skin's barrier function by supporting a balanced, diverse skin microbiome could be a crucial factor for health and longevity.   Our conversation delves into the science of the skin microbiome, how modern products and lifestyles impact it, and practical strategies to keep your skin's ecosystem thriving. Don't miss this episode, which may forever change how you think about skincare and healthy aging.   Kiran Krishnan is the chief microbiologist at Just Thrive with 20 years of experience in the dietary supplement and nutrition market. He comes from a strict research background, having spent several years with hands-on R&D in the fields of molecular medicine and microbiology at the University of Iowa.   To Try SIV Serum for yourself go to SIVCARE.com and use code NAT10 to save on your purchase   Thank you to our sponsors for making this episode possible: Fatty15: Visit http://fatty15.com/NAT and use promo code NAT to save. Vitali: Visit https://www.vitaliskincare.com/discount/Nathalie20 and use code Nathalie20 to save on your order. Berkeley Life: Consumers may register and place an order using my code NIDDBL for 10% off at berkeleylife.com Young Goose: www.Younggoose.com. Use code NAT10 on first order and 5NAT for all future orders   Find more from Kiran Krishnan:  Instagram: @kiranbiome   Find more from Nathalie: YouTube: https://www.youtube.com/channel/UCmholC48MqRC50UffIZOMOQ  Join Nat's Membership Community: https://www.natniddam.com/bsp-community  Sign up for Nats Newsletter: https://landing.mailerlite.com/webforms/landing/i7d5m0  Instagram: https://www.instagram.com/nathalieniddam/  Website: www.NatNiddam.com    Facebook Group: https://www.facebook.com/groups/biohackingsuperhumanperformance  What We Discuss:  03:05 GLP-1 Agonists and Gut Microbiome 19:27 The Barrier Function of the Skin and Aging 24:01 The Acid Mantle and pH of the Skin 28:12 The Role of Ceramides in Skin Health 39:07 Reinforcing and Supporting the Skin Microbiome 41:03 Quorum Sensing and Biome Balancing Serum 43:23 Application of Biome Balancing Serum 46:28 Improving Skin Health and Appearance 49:50 Maintaining Skin Health in a Toxic Environment 50:14 Ideal pH for Skincare Products   Key Takeaways The skin plays a crucial role in longevity and health span, acting as a dynamic barrier and protecting against toxins and pathogens. Maintaining the pH of the skin and the ceramide layer is essential for skin health and preventing age-related skin issues. Phytoceramides, obtained from plants, can help support the health of the skin and may be beneficial in skincare products. The majority of skin care products are not good for the skin microbiome, but it is not feasible to eliminate their use completely.  

Microbes can work work together .... if the conditions are favourable for cooperation. An understanding of quorum sensing offers new perspectives, and thus, treatment perspectives that may decrease disease severity without contributing to antibiotic resistance. The information presented on this podcast is for educational purposes only and is not intended to diagnose or prescribe for any medical or psychological condition, nor prevent, treat, mitigate, or cure any conditions. Please make your own healthcare decisions based on your judgment and research in partnership with a qualified healthcare professional.Become a supporter of this podcast: https://www.spreaker.com/podcast/that-naturopathic-podcast--4229492/support.

Bacteria may be tiny, but we can harness them to create food and medicine, to detect landmines and make blood safe for transfusions. Learn what we're still learning about how bacteria shape us and our world in this episode of BrainStuff, based on these articles: https://science.howstuffworks.com/life/cellular-microscopic/bacteria-communication.htmhttps://science.howstuffworks.com/life/cellular-microscopic/10-weirdest-sources-antibiotics.htm https://science.howstuffworks.com/life/cellular-microscopic/scientists-call-for-global-germ-bank.htm https://science.howstuffworks.com/life/cellular-microscopic/universal-blood-type.htm https://science.howstuffworks.com/bacteria-lasers-landmine-detection.htm See omnystudio.com/listener for privacy information.

TWiM reveals quorum-sensing systems that regulate intestinal inflammation and permeability caused by P. aeruginosa, and how plasmids manipulate bacterial behavior through translational regulatory crosstalk. Hosts: Vincent Racaniello, Michael Schmidt, Michele Swanson, Petra Levin. Become a patron of TWiM. Links for this episode Quorum-sensing in the intestine (mBio) Block quorum sensing, block biofilm (Antimicrob Agents Chemother) Plasmids manipulate bacterial behavior (PLoS Biol) Regulatory genes associated with integrative conjugative elements (J Bact) Take the TWiM Listener survey! Send your microbiology questions and comments (email or recorded audio) to twim@microbe.tv

Quorum Sensing Research Hopes to Reduce Antibiotic Use and Oral Biofilm By Spring Hatfield, RDH, BSPH Original article published on Today's RDH: https://www.todaysrdh.com/quorum-sensing-research-hopes-to-reduce-antibiotic-use-and-oral-biofilm/ This audio article is sponsored by LISTERINE®. Although LISTERINE® Antiseptic is the most extensively tested over-the-counter mouthrisnse in the world, with over 30 long-term clinical trials examining its safety and efficacy, there is still some misinformation out there over the uses of mouthrinses containing alcohol. To help understand the safety of alcohol-containing mouthrines, in case any patients ask you about it, head on over to https://rdh.tv/ListerineSafety Need CE? Start earning CE credits today at https://rdh.tv/ce Get daily dental hygiene articles at https://www.todaysrdh.com Follow Today's RDH on Facebook: https://www.facebook.com/TodaysRDH/ Follow Kara RDH on Facebook: https://www.facebook.com/DentalHygieneKaraRDH/ Follow Kara RDH on Instagram: https://www.instagram.com/kara_rdh/

ヒトの細胞で人工的なクオラムセンシングの構築を目指した論文を紹介しました。Shownotes Synthetic mammalian signaling circuits for robust cell population control. Cell 2022 … 今回sohが紹介する論文です The Elowitz Lab at Caltech Quorum sensing (Wikipedia) 80. Guest explains everything (Researchat.fm) … Pomeさんをゲストに迎え、CAR-T治療などについて教えていただいた回 Nishimura et al. Nature Methods 2009 … “An auxin-based degron system for the rapid depletion of proteins in nonplant cells” Blasticidin S DamID Editorial Notes 随分と収録から公開の間が空いてしまいましたが引き続き論文を紹介していきます (soh) Quorum sensingおもしろいなぁ(tadasu)

When a box of fruit goes bad, usually at the beginning it's just ONE that goes off. The rest seem to be fine. What a mouldy tray of tomatoes can teach us about how to keep our lungs healthy. The basics of quorum sensing (how the mould takes over the whole tray) and how essential oils can prevent that. Also a walkthrough of how to use oils and steam to help our body heal and prevent larger infections in the lungs. Video is helpful. It is here. https://youtu.be/TQEglzyQ-Mo Join the Membership to Access the Joygasmic Birth Blueprint Videos & Courses: https://elenaharderr.com/membership-home/podcast-membership About Elena Harder Elena Harder is on a mission to Nourish Mothers and create Bulletproof Moms. She started her awakening journey in 2010. Even with a challenging hospital birth, an abusive relationship, 7 years spent in crippling postpartum depression, self loathing and people pleasing. She never gave up hope on finding a way through. Her search for “mental health” led Elena to study Mindfulness, Spirituality, NLP, Theta Healing, Tantra, Optimal Nutrition, and Intermittent Fasting to find a way to finally recover her mind and joyful soul. Now she works with other mothers to help them master the tools and skills that really work to remove their negative self talk, eliminate stress, heal their hearts, remove anxiety, fear, depression and be empowered to find their own Joygasmic Life. Get the Free Joygasmic Birth Blueprint eBook at joygasm.me Website: ElenaHarderR.com WyldBirth.com Facebook: Facebook.com/Joygasm8 Instagram: https://instagram.com/JoygasmHarder Huge Thank you to SONNY for our Intro-Outro Song https://open.spotify.com/artist/7woO5xoM5KGReQEEqdexGj --- Send in a voice message: https://anchor.fm/joygasmic/message

Did you know, Essential Oils are basically secret agent spies? I know, like we could possibly love these babies any more! It's called Quorum Sensing, and it's awesome. It works like this: when bad bacteria in our bodies start chatting about how they're going to band together and make us sick, essential oils do a little eavesdropping and decide to basically “cut the phone line” the bacteria are using to communicate. At least that's what it sounds like to me! For the real technical talk, dive into this awesome episode with Dr. Dan Gubler and learn all about quorum sensing and the great clinical trials going on in the field. A definite must listen if you love science! Connect with Dr. Dan through his site HERE or his IG HERE.See full show notes for this episode HERE. Leave us a review while you're there.Lookin' for some podcast goodies? I've got ya covered! Shop our t-shirts, swag, and other popular products HERENew to essential oils? Here is my free guide to help you demystify this topic FREE Essential Oils Guide.Our website is www.RevolutionOilsPodcast.comView hundreds of Essential Oil Recipes in our DIY DugoutSign up for my PODCAST NEWSLETTER and you'll get FREE tips on how to live a healthier, more balanced life! Say hello on social. Use the Hashtag #essentialoilrevolutionpodcast so I know you're a friend!FacebookInstagramGrab yourself a freebie here! ---> https://linktr.ee/samleewrightThank you to our amazing sponsors.Heard about a product you'd like to try? View our list of sponsors HERE and help us keep this podcast 100% free!FAQs:Who is Samantha Lee Wright?Which brand of oils do you recommend and why?Is it safe to ingest essential oils? (And other safety concerns)Are essential oils safe for cats? (See safety section)Hey! Thanks for listening. Send me a message & tell me what you think about the show. Leave a review so others can find the show more easily too.xo,SamSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Bacteria are all around us, and the role these microorganisms play in our environment – both on the farm and inside the animals themselves, is an increasingly important area of study in animal science.Quorum sensing is bacteria's unique biochemical communication system. It's how bacteria interact and talk with each other. Understanding how that communication works and how we can use it in a variety of applications is a new frontier in animal health and wellbeing.To explore how quorum sensing science works and what benefits it offers the dairy industry, Feedstuffs editor Sarah Muirhead talked with Dr. Jeff Brose, director of technical services with AHV International out of Fort Collins, Colorado, to find out more. Prior to joining AHV International, Brose served as a consultant as AHV prepared to enter the U.S. market. He previously held positions with Cargill and Monsanto after managing his own private veterinary practice.

The popular conception of ants is that “anatomy is destiny”: an ant's body type determines its role in the colony, for once and ever. But this is not the case; rather than forming rigid castes, ants act like a distributed computer in which tasks are re-allocated as the situation changes. “Division of labor” implies a constant “assembly line” environment, not fluid adaptation to evolving conditions. But ants do not just “graduate” from one task to another as they age; they pivot to accept the work required by their colony in any given moment. In this “agile” and dynamic process, ants act more like verbs than nouns — light on specialization and identity, heavy on collaboration and responsiveness. What can we learn from ants about the strategies for thriving in times of uncertainty and turbulence?What are the algorithms that ants use to navigate environmental change, and how might they inform the ways that we design technologies? How might they teach us to invest more wisely, to explore more thoughtfully?Welcome to COMPLEXITY, the official podcast of the Santa Fe Institute. I'm your host, Michael Garfield, and every other week we'll bring you with us for far-ranging conversations with our worldwide network of rigorous researchers developing new frameworks to explain the deepest mysteries of the universe.In this episode we talk to SFI External Professor Deborah Gordon at Stanford University about the lessons we can learn from insect species whose individuals cannot be trained, but whose collective smarts have reshaped every continent. We muse on what the ants can teach us about a wide variety of real-world and philosophical concerns, including:  how our institutions age, how to fight cancer, how to build a more resilient Internet, and why the notion of the “individual” is overdue for renovation…If you value our research and communication efforts, please subscribe to Complexity Podcast wherever you prefer to listen, rate and review us at Apple Podcasts, and/or consider making a donation at santafe.edu/podcastgive. You can find numerous other ways to engage with us at santafe.edu/engage. Thank you for listening!Join our Facebook discussion group to meet like minds and talk about each episode.Podcast theme music by Mitch Mignano.Follow us on social media:Twitter • YouTube • Facebook • Instagram • LinkedInKey Links:Deborah Gordon at StanfordDeborah's TED Talk, "What Ants Can Teach Us About Brain Cancer and The Internet"Deborah's Google Scholar PageDeborah's book, Ants at Work: How an Insect Society is OrganizedFurther Exploration:Complexity 10 with Melanie Moses (ants, scaling, and computation)Complexity 29 with David Krakauer (catastrophe and investment strategy)Complexity 56 with J. Doyne Farmer (market ecology)Krakauer, et al., "The Information Theory of Individuality"W. Brian Arthur, "Economics in Nouns & Verbs"Michael Lachmann's research on Costly Signaling and Cancer 

In the late 1960s, Hastings was studying bioluminescence in the marine bacteria Vibrio fischeri. He and his post-doc, Kenneth Nealson, discovered that bacteria could communicate by secreting a small peptide. This allowed V. fischeri to sense the concentration of their fellow bacteria and, when the density reached a critical level, turn on bioluminescence. Hastings named this process autoinduction, also known as quorum sensing. Quorum sensing has since been shown to play a critical role in bacterial behaviors such as toxin production and biofilm formation.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.11.01.364125v1?rss=1 Authors: Narla, A., Borenstein, D. B., Wingreen, N. S. Abstract: Bacteria grow on surfaces in complex immobile communities known as biofilms, which are composed of cells embedded in an extracellular matrix. Within biofilms, bacteria often interact with members of their own species, and cooperate or compete with members of other species via quorum sensing (QS). QS is a process by which microbes produce, secrete, and subsequently detect small molecules called autoinducers (AIs) to assess their local population density. We explore the competitive advantage of QS through agent-based simulations of a spatial model in which colony expansion via extracellular matrix production provides greater access to a limiting diffusible nutrient. We note a significant difference in results based on whether AI production is constitutive or limited by nutrient availability: If AI production is constitutive, simple QS-based matrix-production strategies can be far superior to any fixed strategy. However, if AI production is limited by nutrient availability, QS-based strategies fail to provide a significant advantage over fixed strategies. To explain this dichotomy, we derive a novel biophysical limit for the dynamic range of nutrient-limited AI concentrations in biofilms. This range is remarkably small (less than 10-fold) for the realistic case in which a growth-limiting diffusible nutrient is taken up within a narrow active growth layer. This biophysical limit implies that for QS to be most effective in biofilms, AI production should be a protected function not directly tied to metabolism. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.23.352641v1?rss=1 Authors: Dalwadi, M. P., Pearce, P. Abstract: Bacteria use intercellular signaling, or quorum sensing (QS), to share information and respond collectively to aspects of their surroundings. The autoinducers that carry this information are exposed to the external environment; consequently, they are affected by factors such as removal through fluid flow, a ubiquitous feature of bacterial habitats ranging from the gut and lungs to lakes and oceans. To understand how QS genetic architectures in cells promote appropriate population-level phenotypes throughout the bacterial life cycle requires knowledge of how these architectures determine the QS response in realistic spatiotemporally varying flow conditions. Here, we develop and apply a general theory that identifies and quantifies the conditions required for QS activation in fluid flow by systematically linking cell- and population-level genetic and physical processes. We predict that, when a subset of the population meets these conditions, cell-level positive feedback promotes a robust collective response by overcoming flow-induced autoinducer concentration gradients. By accounting for a dynamic flow in our theory, we predict that positive feedback in cells acts as a low-pass filter at the population level in oscillatory flow, allowing a population to respond only to changes in flow that occur over slow enough timescales. Our theory is readily extendable, and provides a framework for assessing the functional roles of diverse QS network architectures in realistic flow conditions. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.05.327148v1?rss=1 Authors: Janssens, Y., Debunne, N., De Spiegeleer, A., Wynendaele, E., Planas, M., Feliu, L., Quarta, A., Claes, C., Van Dam, D., De Deyn, P. P., Ponsaerts, P., Blurton-Jones, M., De Spiegeleer, B. Abstract: Background Quorum sensing peptides (QSPs) are bacterial peptides produced by Gram-positive bacteria to communicate with their peers in a cell-density dependent manner. These peptides do not only act as interbacterial communication signals, but can also have effects on the host. Compelling evidence demonstrates the presence of a gut-brain axis and more specifically, the role of the gut microbiota in microglial functioning. The aim of this study is to investigate microglial activating properties of a selected QSP (PapRIV) which is produced by Bacillus cereus species. Methods Gastro-intestinal transport of the peptide is investigated using the in vitro Caco-2 model while transport over the blood-brain barrier is investigated in mice using multiple time regression experiments. Microglial activation is assessed using ELISA, fluorometry, immunoblotting, qPCR and phase-contrast microscopy. In vivo plasma detection and ex vivo metabolization experiments are performed using UHPLC-MS/MS and UHPLC-UV/MS, respectively. Results PapRIV showed in vitro activating properties of BV-2 microglia cells and was able to cross the in vitro Caco-2 cell model and pass the blood-brain barrier in vivo. In vivo peptide presence was also demonstrated in mouse plasma. The peptide caused induction of IL-6, TNF and ROS expression and increased the fraction of ameboid BV-2 microglia cells in an NF-{kappa}B dependent manner. Different metabolites were identified in serum, of which the main metabolite (DLPFEH) still remained active. Conclusions PapRIV is thus able to cross the gastro-intestinal tract and the blood-brain barrier and shows in vitro activating properties in BV-2 microglia cells, hereby indicating a potential role of this quorum sensing peptide in gut-brain interaction. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.03.281394v1?rss=1 Authors: Medarametla, P., Laitinen, T., Poso, A. Abstract: Quorum sensing is being investigated as an alternative therapeutic strategy in antibacterial drug discovery to combat bacterial resistance. LsrK is an autoinducer-2 kinase, playing a key role in the phosphorylation of autoinducer-2 (AI-2) signalling molecules involved in quorum sensing. Inhibiting LsrK could result in reduced pathogenicity by interfering with the quorum sensing signalling. Previously, we have generated homology models to identify LsrK inhibitors using structure-based virtual screening and successfully found the first class of LsrK inhibitors. While conducting these studies, the crystal structure of LsrK was released providing us an opportunity to inspect the reliability and quality of our models. Structural analysis of crystal structure and homology models revealed the consistencies of constructed models with crystal structure in the structural fold and binding site. Further, binding characteristics and conformational changes are investigated using molecular dynamics. These simulations provided us insights into the protein function and flexibility that need to be considered during the structure-based drug design studies targeting LsrK. Copy rights belong to original authors. Visit the link for more info

Bacteria talk to each other using molecules that allow them to coordinate group behaviors, which has been termed “quorum sensing”.  A number of bacteria utilize quorum sensing to form gangs that coordinate beneficial behaviors such as symbiotic light production, as well as detrimental behaviors such as attacking their host. Dr. Marvin Whiteley is a Professor at the Georgia Institute of Technology who studies bacterial chatter. He has developed some innovative means to investigate bacterial chitchat, including trapping small clusters of bacteria in tiny synthesized “lobster traps” to see what kind of dialogue ensues.   Dr. Whiteley talks about how and why bacteria talk to each other, whether lab conditions can help us understand what a pathogen does inside a host, how a polymicrobial “love story” in the mouth leads to dental problems, and how his interest in birds with colorful tails led him to a career in microbiology.   microTalk recorded this discussion with Dr. Whiteley at the American Society for Microbiology Microbe 2018 meeting in Atlanta Georgia.      The microCase for listeners to solve is about Kerosene Lampe, an infant who comes down with a scary infectious disease when her mother takes her to “the happiest place in the galaxy”. Participants: Karl Klose, Ph.D. (UTSA) Marvin Whiteley, Ph.D. (Georgia Institute of Technology) Janakiram Seshu, Ph.D. (UTSA) Jesus Romo (UTSA) Subscribe to microTalk via Apple Podcasts, Google Podcasts, Android, Email or RSS and never miss an episode!

Pete Greenberg tells how bacteria can communicate based on cell density, a phenomenon he helped name quorum sensing. He talks about therapeutics based on quorum-sensing discoveries, and how studying bacterial interactions can be used to test ecological principles like cooperation and social cheating. Julie's biggest takeaways: Quorum sensing can be likened to an old-fashioned smoking room, where a few cigar smokers don’t affect the air quality, but as more smokers enter the room, it becomes beneficial to the group to open the window: a changed behavior that benefits the group environment. Differentiating waste molecules from signaling molecules is important to define specific quorum sensing. The experimental evidence that shows that molecules serve as quorum sensing signals that allow bacteria to respond at high density comes from social engineering experiments to identify ‘cheaters.’ Quorum sensing results in changes in gene expression that benefit the community but not necessarily individual cells. An example is antibiotics, which when made by a single cell aren’t at a high enough concentration to kill competitor microbes. As a group, all cells working together can produce a cloud of antibiotic that may be able to protect from competitors. The ability of microbes to receive or ‘eavesdrop’ on the signals produced may be cooperative, but is more likely competitive, giving the eavesdropper a competitive advantage by informing them about another species’ presence. If you knock out quorum sensing, you get abnormal biofilms, but it doesn’t ablate biofilms completely. Although a self-described disinterested high-school student, Greenberg signed up for a weekend field trip to get out of a test on a Friday. It was looking at animals in the intertidal bay of the Pacific Northwest that inspired him to be a biologist! Greenberg also credits his broad biology undergraduate training for preparing him to apply socioecology concepts to bacteria. Quorum sensing was originally called ‘auto induction.’ In the early 1990s, Greenberg was writing a minireview for the Journal of Bacteriology and wanted to think of a catchy title. As Greenberg remembers, coauthor Steve Winans explained the concept to his family, and his brother-in-law said “it’s like the bacteria need a quorum” - the birth of the term ‘quorum sensing.’ Featured Quotes (in order of appearance): “So-called ‘cheaters’ don’t respond to the signal, they’ve lost the ability to respond to the signal. The product that’s useful for the common good any more. They don’t pay the cost of cooperation but they can benefit by the cooperative activity of everyone else in the community...there’s a fitness advantage for cheaters in this environment.” “It’s a real case of convergent evolution. It’s important that the bacteria can do this, and these two really distinct types of [gram-positive and gram-negative] bacteria have evolved completely different mechanisms to perform quorum sensing.” “I think of bacteria as a way to study what is called ‘Darwin’s dilemma.’ If a cheater emerges among a population, it will have a fitness advantage over the population of cooperators. It should take over the population and ultimately cause the tragedy of the commons, where there are too many cheaters and not enough cooperators and the whole system collapses. Darwin’s dilemma is: how is cooperation stabilized? We know it exists and it seems like it shouldn’t - we can use bacteria to get at the rules.” “I got interested in [quorum sensing] because it was so cool!” “I had this idea, as we began to unravel quorum sensing in these marine luminescent bacteria, that any idea in biology that’s a good idea will occur more than once - but I didn’t have any evidence of that. For 15 years, my lab and essentially one other lab, Mike Silverman’s lab, were the only labs working on this. It was really the early 90s when our group and other groups started to realie that lots of bacteria do this. It’s one of those fantastic oddesies. It’s luck - luck and hard work, I guess. Hard work by the people in my lab as I sit around as watch!” “It’s funny how a term can catch on and sort of crystallize a field! But somehow, it seemed to do that. I’ve gotten really into trying to think of catchy terms since then, and the latest one is ‘sociomicrobiology,’ which I introduced with Matt Parsek about 12 years ago and there’s a burgeoning field called sociomicrobiology. I’m trying to think of another term now, before I retire!” Links for this episode   Pete Greenberg lab at the University of Washington Pete Greenberg 2004 PNAS bio Journal of Bacteriology minireview: Quorum Sensing in Bacteria HOM: Woody Hastings memoriam ASM Podcasts     Send your stories about our guests and/or your comments to jwolf@asmusa.org.

They lie in wait, biding their time until their numbers grow. Then suddenly, they strike and wreak havoc upon the harmonious community. You'd think this is a story about revolution, but actually we're talking about the constant battle for supremacy which is being waged inside us. It's called quorum sensing, and it's a mechanism whereby micro-organisms silently grow in number while evading immune surveillance until they are numerous enough to sprout forth and cause an overt infection. They often do this by forming biofilms, which cloak their communities enabling them to evade detection - even antibiotics have a hard time penetrating these coatings! Today, Belinda Reynolds will take us through quorum sensing, biofilms and how we can effectively rebalance our microcosmic communities using natural medicines. *****DISCLAIMER: The information provided on FX Medicine is for educational and informational purposes only. The information provided is not, nor is it intended to be, a substitute for professional advice or care. Please seek the advice of a qualified health care professional in the event something you learn here raises questions or concerns regarding your health.*****

Leberkrebs ist schwer zu diagnostizieren, doch Tal Danino, synthetischer Biologe, hatte eine geniale Idee: Was wäre, wenn wir probiotische, essbare Bakterien "programmieren" könnten, so dass sie Leberkrebs erkennen? Seine Idee basiert auf neuen, bislang nur wenig untersuchten Erkenntnissen über Bakterien: ihre Fähigkeit zum "Quorum Sensing", zu snychronisierten Aktivitäten, nachdem eine kritische Dichte erreicht ist. Der TED Fellow Danino erklärt, wie Quorum Sensing funktioniert – und wie schlaue kooperierende Bakterien die Zukunft der Krebstherapie revolutionieren können.

Mon, 4 May 2015 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/18505/ https://edoc.ub.uni-muenchen.de/18505/1/Rabener_Elaine.pdf Rabener, Elaine ddc:570, ddc:500, Fakultät für Biologie

Pete Greenberg, Department of Microbiology, University of Washington, Seattle WA - USA speaks on "Quorum sensing and cooperation in bacteria: considerations of socialism in the microbial world". This seminar has been recorded by ICGEB Trieste

Zystische Fibrose ist die häufigste vererbbare letale Erkrankung in Europa, die trotz Fortschritten in Diagnostik und Therapie weiterhin mit einer verkürzten Lebenserwartung einhergeht. Einer der Hauptgründe verfrühter Sterblichkeit betroffener Patienten sind persistierende pulmonale Infektionen mit Pseudomonas aeruginosa. Der Keim bedient sich des Quorum Sensing (QS), eines interbakterielles Kommunikationssystems, um die Ausbildung von Virulenzfaktoren zu regulieren und die Immunantwort des Patienten zu beeinflussen. In dieser Arbeit wurde die Auswirkung des P. aeruginosa QS Moleküls 3oxoC12-HSL auf die Reifung humaner Dendritischer Zellen (DZ) untersucht. DZ vermitteln als professionelle Antigen-präsentierende Zellen zwischen angeborenem und erworbenem Immunsystem. Eine Infektion wurde simuliert, indem humane DZ mit Lipopolysaccharid oder Zytokin-Cocktail aktiviert wurden. Anschliessend wurde die Expression von Maturations- und Migrationsmarkern sowie Zytokinsekretion in Anwesenheit von 3oxoC12-HSL untersucht. Bei LPS-stimulierten DZ kam es in Anwesenheit von 3oxoC12-HSL zu einer erniedrigten Expression der Reifungsmarker CD80, CD86, CD83, CD40, HLA-DR, sowie der Migrationsmarker CD184 (CXCR4) und CD197 (CCR7). Die Coinkubation mit Zytokin-Cocktail und 3oxoC12-HSL ergab eine Herabregulierung der Maturationsmarker CD80, CD86 und HLA-DR. Auf unstimulierte DZ zeigte 3oxoC12-HSL keinen Effekt, das Oberflächenmarker-Expressionsprofil dieser Zellen glich dem unreifer DZ. 3oxoC12-HSL inhibierte auch die Sekretion der pro-inflammatorischer Zytokine IL-12, IFN-gamma, MIP-1alpha, TNF-alpha durch LPS- bzw. Zytokin-Cocktail-gereifte DZ. Insgesamt zeigen unsere Ergebnisse, dass 3oxoC12-HSL die Reifung von DZ unterdrückt und somit das Zustandekommen einer effektiven Immunantwort verhindert wird.

A radically different approach to dealing with bacteria would be to stop them from communicating and coordinating attacks, rather than trying to kill them. The bugs would be rendered harmless and much less likely to develop drug resistance. This is the hope of researchers who are working on an aspect of bacterial life known as Quorum Sensing.Medical experts have warned that within 20 years, unless something is done, the spread of antibiotic resistance may have returned us to an almost 19th Century state of medicine. Infections following routine operations will be untreatable and fatal because so many common bacteria will have acquired immunity to all the available antibiotic drugs.The vast majority of the antibiotics we rely upon today were developed between the 1940s and 1970s. There has been no new class of antibiotic for 25 years.Bacteria may just be single-celled organisms but microbiologists now realise they have a kind of social life. They need to cooperate and coordinate their attacks on the bodies they infect. Many kinds of bacteria only become dangerous to us when they sense that their numbers are high enough. Only when they 'know' that there are enough of them to overwhelm human defences, do they release their toxins and cause illness and death.Geoff Watts talks to scientist and doctors who are exploring this phenomenon in disease-causing bacteria. They are trying to devise ways of interfering with microbial communications. One line of thinking is the development of drugs which stop the microbes from either 'talking' or 'hearing' the chemical messages. Another more radical idea, is to treat infected patients with doses of the kind of bacteria causing the illness - except that the 'medicinal' bugs would be ones that would subvert the communication system and bring the infection to an end.

England's chief medical officer recently warned that within twenty years, the spread of antibiotic resistance may have returned us to an almost 19th century state of medicine. Infections following routine operations will be untreatable and fatal because so many common bacteria will have acquired immunity to all the available antibiotic drugs. The vast majority of the antibiotics we rely upon today were developed between the 1940s and 1970s. There has been no new class of antibiotic for 25 years. A radically different approach to dealing with bacteria would be stop them from communicating and coordinating their attacks, rather than trying to kill them. The bugs would be rendered harmless and much less likely to develop drug resistance. This is the hope of researchers who are working on an aspect of bacterial life known as Quorum Sensing. Bacteria may just be single-celled organisms but microbiologists now realise they have a kind of social life. They need to cooperate and coordinate their attacks on the bodies they infect. Many kinds of bacteria only become dangerous to us when they sense that their numbers are high enough. Only when they 'know' that there are enough of them to overwhelm human defences, do they release their toxins and cause illness and death. They monitor the number of their fellow bugs by sensing the concentration of a message molecule which they all manufacture and secrete into the environment. It's a rudimentary form of communication which many bacteria use to synchronise their activities. In Frontiers, Geoff Watts talks to scientist and doctors who are exploring this phenomenon in disease-causing bacteria, and trying to devise ways of interfering with the microbial communications. One line of thinking is the development of drugs which stop the microbes from either 'talking' or 'hearing' the chemical messages. Another more radical idea is to treat infected patients with doses of the kind of bacteria causing the illness - except that the 'medicinal' bugs would be ones that would subvert the communication system and bring the infection to an end. At least, that is the theory.

Bacteria produce and excrete signaling molecules, so called autoinducers, which allow them to monitor their population density and/or their environment in a process best known as quorum sensing. The Gram-negative marine bacterium Vibrio harveyi regulates certain virulence factors like type III secretion, siderophore production, and exoproteolytic activity as well as biofilm formation and bioluminescence using quorum sensing. The bacterium produces three different autoinducers: HAI-1, a N-(3-hydroxybutyryl)-D-homoserine lactone, AI-2, a furanosylborate diester, and CAI-1, a (Z)-3-aminoundec-2-en-4-one. The autoinducers are recognized by the hybrid sensor kinases LuxN, LuxQ and CqsS. All information is transferred to the phosphotransfer protein LuxU and the response regulator LuxO via phosphorelay and further transduced into the copy number of the master regulator LuxR. LuxR induces/represses a multitude of genes/operons (>100) including the lux-operon responsible for the production of bioluminescence. In order to understand how single cells behave within an autoinducer-activated community, autoinducer-induced processes were investigated in a homogeneous environment over time. Analysis of wild type single cells with respect to bioluminescence revealed that even at high cell densities only 70% of the cells of a population were bright. Moreover, fractionation of the population was found for autoinducer-controlled promoters (of genes coding for bioluminescence, exoproteolytic activity, and type III secretion) using reporter strains containing promoter::gfp fusions. These results indicated phenotypic heterogeneity of a genetic homogeneous population and were independent of the used cultivation medium, temperature or strain. An artificial increase of the autoinducer concentrations resulted in an all-bright cell population similar as observed for a luxO deletion mutant. Both, wild type and deletion mutant switched to biofilm formation at high cell density. However, the capability of the mutant to produce biofilm was significantly reduced. These data suggest that a population of the non-differentiating bacterium Vibrio harveyi takes advantages of division of labor. In addition, a temporal variation of the autoinducer concentrations over time was found. The extracellular concentrations of the three autoinducers and quorum sensing-regulated functions of Vibrio harveyi were monitored in a growing culture. In the early and mid-exponential growth phase only AI-2 was detectable and bioluminescence was induced. In the late exponential growth phase both, HAI-1 and AI-2 reached their maximum values, bioluminescence stayed high and exoproteolytic activity was induced. The stationary phase was characterized by equal concentrations of HAI-1 and AI-2, exoproteolytic activity reached its maximum, and CAI-1 activity was detectable in the culture fluids. Furthermore, only a stable and mature biofilm was formed, when HAI-1 and AI-2 were present in the above described ratios over time. CAI-1 had no influence on the biofilm formation in Vibrio harveyi. These results demonstrate that not the cell density per se is important, but that autoinducers rather control the development of a Vibrio harveyi population.

Sándor Pongor, ICGEB, Trieste, Italy speaks on "Models of quorum sensing communities". This seminar has been recorded by ICGEB Trieste

Peter Greenberg, University of Washington, USA speaks on "Sociomicrobiology: Quorum Sensing Circuits in Pseudomonas aeruginosa..". This seminar has been recorded by ICGEB Trieste

Stephen Farrand, University of Illinois at Urbana, USA speaks on "Sensing the Right Place, Sensing the Right Time: Variations on the Quorum-Sensing System that Regulates Plasmid Transfer in the Alpha-Proteobacteria". This seminar has been recorded by ICGEB Trieste

Die Signaltransduktionskaskade des komplexen Quorum sensing-Systems in Vibrio harveyi umfasst die drei Hybridsensorkinasen LuxN, LuxQ und CqsS, das Histidinphosphotransferprotein LuxU und den Antwortregulator LuxO. Bei niedriger Zelldichte funktionieren die Hybridsensorkinasen als Autokinasen. Die Phosphorylgruppe wird zunächst intramolekular übertragen und anschließend auf LuxU und LuxO weitergeleitet. Phosphoryliertes LuxO aktiviert die Expression von fünf regulatorischen RNAs, die im Zusammenspiel mit dem RNA-Chaperon Hfq die Translation der mRNA des Masterregulators LuxR inhibieren. Bei hoher Zelldichte wird die Kinaseaktivität der Hybridsensorkinasen durch die jeweiligen Autoinduktoren (LuxN: HAI-1, LuxQ: AI-2, CqsS: CAI-1) inhibiert, sodass es zum Abschalten der Phosphorylierungskaskade und zur Anreicherung von LuxR kommt. Im Rahmen dieser Arbeit wurden die Proteine LuxN und LuxO biochemisch näher charakterisiert. Mit Hilfe diverser Methoden konnte die Topologie des Membranproteins LuxN, zusammen mit der Lage des N-Terminus, gelöst werden: das Protein besteht aus neun Transmembrandomänen mit einem periplasmatisch lokalisierten N-Terminus. Im Zuge der biochemischen Charakterisierung von LuxN wurden zwei an der Bindung des Autoinduktors HAI-1 beteiligte Aminosäuren identifiziert. Das Membranprotein LuxN wurde erfolgreich gereinigt und in Escherichia coli- und V. harveyi-basierten Proteoliposomen rekonstituiert. Ebenso wurde der in Form von Inclusion Bodies heterolog in E. coli überproduzierte Antwortregulator LuxO gereinigt und renaturiert. Das renaturierte Protein konnte erstmalig mit dem niedermolekularen Phosphodonor [γ-32P]-Acetylphosphat markiert werden und eine Bindung an die DNA in phosphorylierter und nicht-phosphorylierter Form im Bereich der hypothetischen σ54- und LuxO-Bindestelle gezeigt werden.

Wed, 15 Oct 2008 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/10323/ https://edoc.ub.uni-muenchen.de/10323/1/Stambrau_Nina.pdf Stambrau, Nina ddc:570, ddc:

Pseudomonas aeruginosa ist ein bedeutender Erreger nosokomialer Infektionen. Besondere Bedeutung erlangt es im Krankheitsverlauf der Cystischen Fibrose. Hier und bei anderen Erkrankungen kann die Expression verschiedener Virulenzfaktoren zu schweren Verläufen führen. Ein Typ-III-Sekretions-positiver Phänotyp, das heißt der Besitz des ExoS-Regulons, ist dabei von prognostischem Wert hinsichtlich Gewebszerstörung, Krankheitsverlauf und Überleben. Bisher ist jedoch wenig über die Regulation des ExoS-Regulon bekannt. Sinnvoll erscheint eine gegensätzliche Expression mit dem Typ-II-Sekretionssytem, da hier zahlreiche degradierende Enzyme sezerniert werden, die auch den Typ-III-Sekretionsapparat beschädigen könnten, und mit der Biofilmbildung, da für Typ-III-Sekretion ein direkter Zellkontakt zur Wirtszelle notwendig ist. Bekannte Regulatoren von Biofilmbildung und Typ-II-Sekretion sind Quorum Sensing, der Sigmafaktor der Stationären Phase (RpoS) und der AlgU-Antisigmafaktor MucA für die Alginatsynthese. In der vorliegenden Arbeit wurden daher ihre Auswirkungen auf die Typ-III-Sekretion untersucht. Hierbei zeigt sich unter Stimulationsbedingungen für Typ-III-Sekretion in vitro und durch Kokulturversuche mit humanen Zellen, daß P. aeruginosa in einem Biofilm nahezu kein ExoS exprimiert. Im Gegensatz dazu werden im Überstand dieser Kokultur größere Mengen an Exotoxin S durch planktonisch wachsende Bakterien erzeugt. Es ließ sich zeigen, daß das rhl-Quorum-Sensing-System von P. aeruginosa die Expression von ExoS und ExoU hemmen kann. Ebenso vermindert der Sigmafaktor der Stationären Phase RpoS die Expression von exoS ebenfalls stark. Die Mutation des AlgU-Antisigmafaktors MucA führt zu einem Anstieg von ExoS in der stationären Phase. Ein möglicher Regulationsweg durch Quorum Sensing besteht in der Aktivierung von ExsD, einem negativen Regulator des ExoS-Regulons. exsD besitzt in der Promotorregion eine Sequenz, die einer lux-Box, das heißt einer Bindungsstelle für die Regulatorproteine (RhlR, LasR) des Quorum Sensing, entspricht. Diese Ergebnisse zeigen, daß die Typ-III-sezernierten Exotoxine durch die oben genannten Faktoren reguliert werden können. Dadurch könnte die Expression des ExoS-Regulons im wesentlichen auf die exponentielle Phase beschränkt und in der stationären Phase und im Biofilm gehemmt werden. Zum anderen kann die verstärkte Expression von Typ-III-sezernierten Exotoxinen bei Mutation des mucA-Genes zur erhöhten Virulenz von mucoiden Isolaten von P. aeruginosa in vivo beitragen.

Ziel der vorliegenden Arbeit war es, verschiedene physiologische Parameter hinsichtlich ihres Einflusses auf die Kolonisierungs- und Plasmidtransfereffizienz von P. chlororaphis SPR044 in der Rhizosphäre von A. thaliana zu untersuchen. Zu diesem Zweck wurden TnMod-Insertionsderivate mit Veränderungen "Quorum-Sensing"-regulierter Funktionen untersucht. Darüber hinaus sollten Auswirkungen von pJP4 auf die Fitness von SPR044 festgestellt werden. Weiterhin sollte eine Strategie zur in situ-Detektion plasmid-tragender Stämme in der Rhizosphäre entwickelt werden. Folgende Ergebnisse wurden erhalten: Das natürliche Isolat P. chlororaphis SPR044 produzierte BHSL, 3-OH-OHSL und ein weiteres, bisher nicht identifiziertes Acyl-HSL. Alle drei Acyl-HSLs wurden ebenfalls von den PCN-negativen SPR044-Derivaten sowie vom PCN-Überproduzierer produziert, nicht jedoch von den "Quorum-Sensing"-negativen Derivaten. Entsprechend der regulatorischen Funktion der Acyl-HSLs zeigten quantitative Analysen eine Korrelation zwischen der Menge von produzierten Acyl-HSLs, antimikrobiellen Metaboliten und extrazellulären Proteasen. Die einzige Ausnahme bildete der PCN-Überproduzierer. Dessen PCN-Überproduktion basiert vermutlich auf einer Veränderung des LPS und nicht auf der Ausschaltung eines negativen Regulators. In Einzelkultivierungs-Experimenten zeigte sich nach 14 Tagen kein Unterschied zwischen den Populationsgrößen des Wildtyps und der Derivate. Nach 28 und 42 Tagen war die Population des Wildtyps gleich groß wie die des PCN-negativen Derivats und signifikant größer als die des gacS-negativen Derivats und des PCN-Überproduzierers. In Kokultivierungs-Experimenten war die Population des gacS-negativen Derivats hingegen stets gleich groß wie die des Wildtyps. Eine Erklärung dieses Phänomens konnte durch Untersuchung der Wachstumskinetiken in Flüssigkultur erbracht werden. Die "Quorum-Sensing"-negativen Derivate wiesen eine stark verkürzte Lag-Phase und eine reduzierte Produktion des für die stationäre Phase spezifischen Sigmafaktors Rpos auf. Dies führte nach Koinokulation mit anderen Bakterien offenbar zu einer Aufhebung des selektiven Nachteils. Vermutlich nutzen die gacS-negativen Stämme komplexe C-Quellen, die durch die Enzyme des Wildtyps zugänglich gemacht werden und profitieren darüber hinaus von der verkürzten Lag-Phase. Die Frequenz des konjugativen pJP4-Transfers von SPR044 zu R. eutropha ist unabhängig von "Quorum-Sensing"- und PCN-Produktion. Die Transformation mit pJP4 per se hatte keinen negativen Einfluss auf die Rhizosphäre-Kolonisierungseffizienz von SPR044. Lag jedoch zusätzlich abiotischer oder biotischer Stress vor, manifestierte sich die metabolische Last durch pJP4 in einer verringerten Populationsgröße. Dieser Effekt war unabhängig vom "Quorum-Sensing"-System und der PCN-Produktion von SPR044. VirB5 von A. tumefaciens assembliert in einer höhermolekularen Struktur, die durch Scherkräfte von der Zelle gelöst und mittels Ultrazentrifugation sedimentiert werden kann. Bei verschiedenen Reinigungsschritten wurde eine Kofraktionierung mit der Haupt-Piluskomponente VirB2 beobachtet. VirB5 ist somit eine Nebenkomponente des T-Pilus. Das homologe Protein TraC aus dem IncN-Plasmid übt vermutlich eine ähnliche Funktion in pKM101-determinierten Pili aus. Zellfraktionierung pJP4-tragender P. chlororaphis-Zellen und Detektion mit spezifischen Antiseren deuten darauf hin, dass TrbC und TrbF Haupt- und Nebenkomponente pJP4-determinierter Pili sind. Bei TrbH handelt es sich um ein membran-assoziiertes Lipoprotein. Die Detektion pJP4-tragender Bakterien aus der Rhizosphäre war mit den TrbF- und TrbH-spezifischen Antiseren in situ möglich. Das TrbF-spezifische Antiserum ermöglichte die Erkennung IncP-Plasmid-tragender Bakterien. Das TrbH-spezifische Antiserum ermöglichte eine zusätzliche Unterscheidung zwischen IncPa- und IncPß-Plasmid-tragenden Zellen. Eine Kombination der Immunfluoreszenz-Analyse mit FISH erwies sich als geeignet für die Detektion von pJP4-Transfer zwischen SPR044 und R. eutropha in der Rhizosphäre von A. thaliana.