Podcasts about sulfolobus

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.08.04.552066v1?rss=1 Authors: Charles-Orszag, A., van Wolferen, M., Lord, S. J., Albers, S.-V., Mullins, D. Abstract: Type IV pili are ancient and widespread filamentous organelles found in most bacterial and archaeal phyla where they support a wide range of functions, including substrate adhesion, DNA uptake, self aggregation, and cell motility. In most bacteria, PilT-family ATPases disassemble adhesion pili, causing them to rapidly retract and produce twitching motility, important for surface colonization. As archaea do not possess homologs of PilT, it was thought that archaeal pili cannot retract. Here, we employ live-cell imaging under native conditions (75{degrees}C and pH 2), together with automated single-cell tracking, high-temperature fluorescence imaging, and genetic manipulation to demonstrate that S. acidocaldarius exhibits bona fide twitching motility, and that this behavior depends specifically on retractable adhesion pili. Our results demonstrate that archaeal adhesion pili are capable of retraction in the absence of a PilT retraction ATPase and suggests that the ancestral type IV pilus machinery in the last universal common ancestor (LUCA) relied on such a bifunctional ATPase for both extension and retraction. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Why don't we ever talk about archaea? What can we learn from this domain of life? Why would someone want to cook a chicken in a Yellowstone National Park geyser? Find out about these things and more on this week's TLB episode. Dr. Arthur Charles-Orszag is here to teach us about Sulfolobus acidocaldarius, a sulfur-oxidizing archaeon that lives in super hot and acidic environments. We discuss Arthur's work studying DNA segregation in this microbe and we also unpack many common misconceptions about Archaea as a domain of life.Dr. Arthur Charles-Orszag, PhD is a postdoctoral fellow in the Mullins Lab at University of California-San Francisco. You can find his work on ResearchGate and follow on Twitter: @A_CharlesOrszag. Arthur is also heavily involved with Archaea Power Hour. You are encouraged to sign up for the e-mail list and/or the Slack channel on archaea.page.For more info on microbes and to follow updates of this podcast, find @couch_microscopy on Instagram, @CouchMicroscopy on Twitter, or visit www.couchmicroscopy.com/store for merch!Music is "Introducing Cosmic Space" by Elf Power and "Vorticella Dreams" by L. Felipe Benites.While some of the content on this podcast may be relevant to human or veterinary medicine, this information is not medical advice. The views and opinions expressed on this program are those of the host and guests and do not reflect the views of any institution.

Picture an active, bubbling volcano, or, if you can, a hydrothermal vent, or even perhaps a cauldron full of boiling hot water into which you now add some acid. Do you particularly associate this imagery with life? It’s hard to imagine that there could be living things in these conditions, yet there are microbes that eat, breathe, and flourish in these places. These bugs are extremophiles, literally, lovers of the extreme. How do they survive and thrive in their intense home environments? In this podcast episode, Annika and Nana Ansuah interview Dr. Paula Welander, a Stanford professor whose research lies at the intersection of geology and microbiology, about her recently published paper on extremophiles called Sulfolobus acidocaldarius. Her group showed for the first time that a modification in the membranes of Sulfolobus allows it to live in its extreme home--the hot acid soup you pictured above--and to survive when these conditions fluctuate. Dr. Welander also takes us through her path to geomicrobiology and how her work can inform investigations about life on the ancient earth. Many thanks to Dr. Welander for the interview! Image credit: “Microbial mat” by Supercarwaar is licensed under CC BY-SA 4.0 Music credits: “Vivaldi Winter mvt 1 Allegro non molto - The USAF Concert.ogg” by Antonio Vivaldi performed by The USAF Concert Band and Singing Sergeants is licensed under CC-PD-Mark. “jazzy whatever” by Annika Brakebill.

Hosts: Vincent Racaniello, Dickson Despommier, Alan Dove, Rich Condit, and Kathy Spindler The TWiVniks discuss the structure of a virus that reproduces in an extreme environment, long-term consequences of Ebolavirus infection, and VirScan, a method to identify the different virus infections you have had in your lifetime. Links for this episode Virus with A-form DNA (Science) Viruses in the extreme (virology blog) Sequelae of Ebolavirus infection (Lancet Inf Dis) Long term Ebolavirus effects (virology blog) Take the chili ME challenge Serological profiling of human viral infections (Science) Your viral past (virology blog) Letters read on TWiV 342 Timestamps by Jennifer. Thank you! Weekly Science Picks Dickson - Incredible photosAlan - Alone in a room full of science writersKathy - Calico cats and Siamese catsRich - Missing link in evolutionVincent - Podcasts saving NPR and Podcasting blossoms Listener Pick of the Week Jenny - What Bill Gates is afraid ofNeva - The Kardashian Index Send your virology questions and comments (email or mp3 file) to twiv@twiv.tv

Hosts: Vincent Racaniello, Alan Dove, Rich Condit, Dickson Despommier, and Ken Stedman The complete TWiV team meets with Ken Stedman to discuss the discovery in Boiling Spring Lake of a DNA virus with the capsid of an RNA virus. Subscribe to TWiV (free) in iTunes , at the Zune Marketplace, by the RSS feed, by email, or listen on your mobile device with the Microbeworld app. Links for this episode: Novel virus from an extreme environment (Biol Direct, virology blog) Lassen Volcanic National Park Tombusviridae, Circoviridae (ViralZone) TWiV on Facebook Letters read on TWiV 195 Weekly Science Picks Ken - The Edge of Life trailer and Facebook pageDickson - The Cognitive Style of Powerpoint by Edward TufteAlan - SEMs of insects and spiders via Steve GschmeissnerRich - Curiosity Has Landed (Wiki mission summary)Vincent - Curiosity's Seven Minutes of Terror (YouTube) Listener Pick of the Week Lance - The Vaccine Confidence Project and Immune response video (YouTube)Anat - Beautiful Science Send your virology questions and comments (email or mp3 file) to twiv@twiv.tv, or call them in to 908-312-0760. You can also post articles that you would like us to discuss at microbeworld.org and tag them with twiv.

Rachel Whitaker is an assistant professor of microbiology at the University of Illinois at Urbana-Champaign, where she has developed a research program focused on the evolutionary ecology of microorganisms. Much of Dr. Whitaker’s work centers around a hyperthermophile found in geothermal springs: the archaeon Sulfolobus islandicus. Evolution is not just history – it’s still in action today, molding humans, plants, animals and, of course, microbes, in ways we still don’t completely understand. One of Whitaker’s focus areas is archaea, a group of single-celled microbes that are found in some of the harshest environments on earth. By looking at how one variety of archaea, Sulfolobus, varies from place to place, Whitaker hopes to find whether Sulfolobus is adapting new characteristics to suit its habitats, and whether this kind of adaptation can help us explain why there are so many different kinds of microbes in the world. In this interview, I asked Dr. Whitaker about the hot springs where she studies Sulfolobus, whether it’s hard to communicate with ecologists who work with bigger organisms, and about new discoveries she’s made related to an immune system in archaea.

Dynamic remodeling of chromatin or other persistent protein:DNA complexes is essential for genome expression and maintenance. Proteins of the SWI2/SNF2 family catalyze rearrangements of diverse protein:DNA complexes. Although SWI2/SNF2 enzymes exhibit a diverse domain organisation, they share a conserved catalytic ATPase domain that is related to superfamily II helicases through the presence of seven conserved sequence motifs. In contrast to helicases, SWI2/SNF2 enzymes lack helicase activity, but use ATP hydrolysis to translocate on DNA and to generate superhelical torsion into DNA. How these features implicate remodeling function or how ATP hydrolysis is coupled to these rearrangements is poorly understood and suffers from the lack of structural information regarding the catalytic domain of SWI2/SNF2 ATPase In this PhD thesis I characterized the catalytic domain of Sulfolobus solfataricus Rad54 homolog (SsoRad54cd). Like the eukaryotic SWI2/SNF2 ATPases, SsoRad54cd exhibits dsDNA stimulated ATPase activity, lacks helicase activity and has dsDNA translocation and distortion activity. These activities are thereby features of the conserved catalytic ATPase domain itself. Furthermore, the crystal structures of SsoRad54cd in absence and in complex with its dsDNA substrate were determined. The Sulfolobus solfataricus Rad54 homolog catalytic domain consists of two RecA-like domains with two helical SWI2/SNF2 specific subdomains, one inserted in each domain. A deep cleft separates the two domains. Fully base paired duplex DNA binds along the domain 1: domain 2 interface in a position, where rearrangements of the two RecA-like domains can directly be translated in DNA manipulation. The binding mode of DNA to SsoRad54cd is consistent with an enzyme that translocate along the minor groove of DNA. The structure revealed a remarkable similarity to superfamily II helicases. The related composite ATPase active site as well as the mode of DNA recognition suggests that ATP-driven transport of dsDNA in the active site of SWI2/SNF2 enzymes is mechanistically related to ATP-driven ssDNA in the active site of helicases. Based on structure-function analysis a specific model for SWI2/SNF2 function is suggested that links ATP hydrolysis to dsDNA translocation and DNA distortion. The represented results have structural implications for the core mechanism of remodeling factors. If SWI2/SNF2 ATPases are anchored to the substrate protein:DNA complex by additional substrate interacting domains or subunits, ATP-driven cycles of translocation could transport DNA towards or away from the substrate or generate torsional stress at the substrate:DNA interface. Finally, I provide a molecular framework for understanding mutations in Cockayne and X-linked mental retardation syndromes. Mapping of the mutations on the structure of SsoRad54cd reveal that the mutations colocalize in two surface clusters: Cluster I is located adjacent to a hydrophobic surface patch that may provide a macromolecular interaction site. Cluster II is situated in the domain 1 : domain 2 interface near the proposed pivot region and may interfere with ATP driven conformational changes between domain 1 and domain 2.

Zusammenfassung 1. Das für das Proteolipid aus Methanocaldococcus jannaschii kodierende Gen atpK wurde in E. coli DH5alpha und in dem Minizell-Produzenten E. coli DK6 exprimiert. Das Genprodukt wurde durch radioaktive Markierung nachgewiesen. 2. Aus den Membranen der thermophilen, hydrogenotrophen methanogenen Archaea M. jannaschii, Methanothermobacter thermautotrophicus, Methanothermobacter marburgensis sowie aus den Membranen des mesophilen, methylotrophen methanogenen Archäons Methanosarcina mazei Gö1 wurden mit Chloroform/Methanol die Proteolipide der A1AO-ATPasen und die MtrD-Untereinheiten der Methyltetrahydromethanopterin:CoenzymM-methyl-transferase extrahiert. Die einzelnen Peptide wurden mittels N-terminaler Sequenzierung identifiziert. 3. Durch MALDI-TOF-Analyse wurde die molekulare Masse des maturen Proteolipids aus M. jannaschii zu 21316 Da und 21183 Da (Methionin-freie Form) bestimmt. Zusammen mit der Gensequenz konnte daraus gefolgert werden, daß es sich um eine triplizierte Form des bakteriellen 8-kDa Proteolipids handelt, also 3 Haarnadel-Domänen ausweist. Die ionentranslozierenden Carboxylate sind nur in Haarnadel 2 und 3 konserviert. Bei einer angenommenen Anzahl von 24 Helices im c-Oligomer bedeutet das, daß ein Ionen/ATP-Verhältnis von 2,7 für die Synthese von ATP ausreichen würde. 4. Die Proteolipide aus M. thermautotrophicus und M. marburgensis besitzen duplizierte Proteolipide. Die aktiven Carboxylat-Reste sind im Gegensatz zu den bisher bekannten duplizierten Proteolipiden der V1VO-ATPasen in beiden Haarnadeln konserviert. 5. Die archäellen A1AO-ATPasen-Operone der Pyrococcen enthalten ebenfalls Gene, die für duplizierte Proteolipide kodieren. Allerdings sind die für die Ionentranslokation essentiellen Carboxylat-Reste wie in den Proteolipiden der V-Typ-ATPasen nur in der zweiten Haarnadel vorhanden. Die Abtrennung der A1AO- und V1VO-ATPasen muß daher vor der Entwicklung der Eukaryonten erfolgt sein. 6. Sequenzanalysen haben gezeigt, daß das Proteolipid-Gen aus Methanopyrus kandleri dreizehnmal so groß wie das aus Bakterien ist. Es kodiert für ein Protein mit 13 Haarnadel-Domänen. Die Ionenbindstelle ist in jeder Haarnadel konserviert. 7. Alle heute bekannten Formen der Proteolipide der V- und F-ATPasen waren schon in den Archaea enthalten. Die Vielfalt an Proteolipid-Größen und -Formen der archäellen ATPasen läßt vermuten, daß sie ein Reservoir an Möglichkeiten darstellen, aus denen die V1VO- und F1FO-ATPasen gespeist wurden. 8. Durch Sequenzvergleich mit den Na+-translozierenden Proteolipiden der bakteriellen F1FO-ATPasen wurde auch in den Proteolipiden der A1AO-ATPasen ein Na+-Bindemotiv identifiziert. Es lautet: P/S/T-XXX-Q/E (Motiv I in Helix eins), ET/S (Motiv II in Helix zwei). 9. Aus Membranen von Sulfolobus acidocaldarius und M. jannaschii wurden durch Chloroform/Methanol Lipide extrahiert, anschließend wurde aus diesen Lipiden Liposomen hergestellt, in die die A1AO-ATPase aus M. jannaschii rekonstituiert wurde. Die Synthese von ATP konnte jedoch nicht nachgewiesen werden. 10. Die ATPase-Gene ahaE, ahaC, ahaF, ahaA, ahaB, ahaD und ahaG wurden in den Fusionsvektor pMal kloniert und in Escherichia coli exprimiert. Die Fusionsproteine wurden aus dem Zellextrakt isoliert und zur Immunisierung von Kanninchen eingesetzt. Die erhaltenen Antiseren gegen die ATPase-Untereinheiten AhaA, AhaB, AhaC und AhaE waren spezifisch und wurden für die Analysen dieser Arbeit eingesetzt. 11. Das für die gesamte A1AO-ATPase kodierende Operon ahaHIKECFABDG des methanogenen Archäons Methanosarcina mazei Gö1 wurde in den Expressionsvektor pVSBAD2 hinter den ara-Promotor kloniert. Das Konstrukt wurde pRT1 genannt. 12. Die auf pRT1 lokalisierten Gene wurden heterolog in E. coli DK8 exprimiert. Die A1AO-ATPase war in E. coli membran-assoziiert und funktionell. Die spezifische ATPase-Aktivität an Membranen von E. coli DK8 betrug 150 mU/mg Protein. 13. DCCD und der für archäelle ATPasen spezifische Inhibitor DES hemmten das Enzym. Die I50-Wert betrugen 0,5 mM/mg Protein, beziehungsweise 200 nmol/mg Protein. 14. Die Synthese von AhaA, AhaB, AhaC, AhaE, AhaH, AhaK, und zum ersten Mal auch des gesamten AhaI, konnten nachgewiesen werden. Gegen AhaF, AhaD und AhaG lagen keine funktionellen Antikörper vor.