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Tad pili play a dynamic role in Caulobacter crescentus surface colonization [article]

Urs Jenal, Matteo Sangermani, Isabelle Hug, Nora Sauter, Thomas Pfohl
2019 bioRxiv   pre-print
Bacterial surface attachment is mediated by rotary flagella and filamentous appendages called pili. Here, we describe the role of Tad pili during surface colonization of Caulobacter crescentus. Using an optical trap and microfluidic controlled flow conditions as a mimic of natural environments, we demonstrate that Tad pili undergo repeated cycles of extension and retraction. Within seconds after establishing surface contact, pili reorient cells into an upright position promoting walking-like
more » ... ements against the medium flow. Pili-mediated positioning of the flagellated pole close to the surface facilitates motor-mediated mechanical sensing and promotes anchoring of the holdfast, an adhesive substance that affords long-term attachment. We present evidence that the second messenger c-di-GMP regulates pili dynamics during surface encounter in distinct ways, promoting increased activity at intermediate levels and retraction of pili at peak concentrations. We propose a model, in which flagellum and Tad pili functionally interact and together impose a ratchet-like mechanism that progressively drives C. crescentus cells towards permanent surface attachment.
doi:10.1101/526160 fatcat:wdmnsjjkinhhrgjnqrxvvl6a4q

Tad Pili Play a Dynamic Role in Caulobacter crescentus Surface Colonization

Matteo Sangermani, Isabelle Hug, Nora Sauter, Thomas Pfohl, Urs Jenal, Lotte Søgaard-Andersen
2019 mBio  
Bacterial surface attachment is mediated by filamentous appendages called pili. Here, we describe the role of Tad pili during surface colonization of Caulobacter crescentus. Using an optical trap and microfluidic controlled flow conditions to mimic natural environments, we demonstrated that Tad pili undergo repeated dynamic cycles of extension and retraction. Within seconds after establishing surface contact, pilus retraction reorients cells into an upright position, promoting walking-like
more » ... ents against the medium flow. Pilus-mediated positioning of the flagellate pole close to the surface facilitates motor-mediated mechanical sensing and promotes anchoring of the holdfast, an adhesive substance that affords long-term attachment. We present evidence that the second messenger c-di-GMP regulates pilus dynamics during surface encounter in distinct ways, promoting increased activity at intermediate levels and retraction of pili at peak concentrations. We propose a model in which flagellum and Tad pili functionally interact and together impose a ratchet-like mechanism that progressively drives C. crescentus cells toward permanent surface attachment. IMPORTANCE Bacteria are able to colonize surfaces in environmental, industrial, and medical settings, where they form resilient communities called biofilms. In order to control bacterial surface colonization, microbiologists need to gain a detailed understanding of the processes that bacteria use to live at the liquid-surface interface and that allow them to adhere to and move on surfaces and eventually grow and persist on solid media. To facilitate these processes, bacteria are equipped with adhesive structures such as flagella and pili and with matrix components such as exopolysaccharides. How these cellular organelles are coordinated to optimize surface processes is currently subject to intense investigations. Here we used the model organism Caulobacter crescentus to demonstrate that polar pili are highly dynamic structures that are functionally interconnected with the flagellar motor to mediate surface sensing, thereby enforcing rapid and permanent surface attachment. These studies provide an entry point for an in-depth molecular analysis of bacterial surface colonization.
doi:10.1128/mbio.01237-19 pmid:31213565 pmcid:PMC6581867 fatcat:yjkeegbg4fenncaq2ljcndsug4

Biocatalytic atom transfer radical polymerization in a protein cage nanoreactor

Kasper Renggli, Nora Sauter, Martin Rother, Martin G. Nussbaumer, Raphael Urbani, Thomas Pfohl, Nico Bruns
2017 Polymer Chemistry  
The ATRP-catalyzing enzyme horseradish peroxidase was encapsulated into the protein cage thermosome resulting in an all-protein nanoreactor system for controlled radical polymerizations.
doi:10.1039/c6py02155g fatcat:572xtcondffdpds6esqv55sohy

openBEB: open biological experiment browser for correlative measurements

Chandrasekhar Ramakrishnan, Andrej Bieri, Nora Sauter, Sophie Roizard, Philippe Ringler, Shirley A Müller, Kenneth N Goldie, Kaloyan Enimanev, Henning Stahlberg, Bernd Rinn, Thomas Braun
2014 BMC Bioinformatics  
New experimental methods must be developed to study interaction networks in systems biology. To reduce biological noise, individual subjects, such as single cells, should be analyzed using high throughput approaches. The measurement of several correlative physical properties would further improve data consistency. Accordingly, a considerable quantity of data must be acquired, correlated, catalogued and stored in a database for subsequent analysis. Results: We have developed openBEB (open
more » ... cal Experiment Browser), a software framework for data acquisition, coordination, annotation and synchronization with database solutions such as openBIS. OpenBEB consists of two main parts: A core program and a plug-in manager. Whereas the data-type independent core of openBEB maintains a local container of raw-data and metadata and provides annotation and data management tools, all data-specific tasks are performed by plug-ins. The open architecture of openBEB enables the fast integration of plug-ins, e.g., for data acquisition or visualization. A macro-interpreter allows the automation and coordination of the different modules. An update and deployment mechanism keeps the core program, the plug-ins and the metadata definition files in sync with a central repository. Conclusions: The versatility, the simple deployment and update mechanism, and the scalability in terms of module integration offered by openBEB make this software interesting for a large scientific community. OpenBEB targets three types of researcher, ideally working closely together: (i) Engineers and scientists developing new methods and instruments, e.g., for systems-biology, (ii) scientists performing biological experiments, (iii) theoreticians and mathematicians analyzing data. The design of openBEB enables the rapid development of plug-ins, which will inherently benefit from the "house keeping" abilities of the core program. We report the use of openBEB to combine live cell microscopy, microfluidic control and visual proteomics. In this example, measurements from diverse complementary techniques are combined and correlated.
doi:10.1186/1471-2105-15-84 pmid:24666611 pmcid:PMC3987129 fatcat:33lyusgpjncuddbrqipz2u5ugm

Single-cell lysis for visual analysis by electron microscopy

Simon Kemmerling, Stefan A. Arnold, Benjamin A. Bircher, Nora Sauter, Carlos Escobedo, Gregor Dernick, Andreas Hierlemann, Henning Stahlberg, Thomas Braun
2013 Journal of Structural Biology  
The stochastic nature of biological systems makes the study of individual cells a necessity in systems biology. Yet, handling and disruption of single cells and the analysis of the relatively low concentrations of their protein components still challenges available techniques. Transmission electron microscopy (TEM) allows for the analysis of proteins at the single-molecule level. Here, we present a system for single-cell lysis under light microscopy observation, followed by rapid uptake of the
more » ... ell lysate. Eukaryotic cells were grown on conductively coated glass slides and observed by light microscopy. A customdesigned microcapillary electrode was used to target and lyse individual cells with electrical pulses. Nanoliter volumes were subsequently aspirated into the microcapillary and dispensed onto an electron microscopy grid for TEM inspection. We show, that the cell lysis and preparation method conserves protein structures well and is suitable for visual analysis by TEM.
doi:10.1016/j.jsb.2013.06.012 pmid:23816812 fatcat:6xuetkdjuvekphw4otpktczstm

Live cell X-ray imaging of autophagic vacuoles formation and chromatin dynamics in fission yeast

Natalja Strelnikova, Nora Sauter, Manuel Guizar-Sicairos, Michael Göllner, Ana Diaz, Petrina Delivani, Mariola Chacón, Iva M. Tolić, Vasily Zaburdaev, Thomas Pfohl
2017 Scientific Reports  
Seeing physiological processes at the nanoscale in living organisms without labeling is an ultimate goal in life sciences. Using X-ray ptychography, we explored in situ the dynamics of unstained, living fission yeast Schizosaccharomyces pombe cells in natural, aqueous environment at the nanoscale. In contrast to previous X-ray imaging studies on biological matter, in this work the eukaryotic cells were alive even after several ptychographic X-ray scans, which allowed us to visualize the
more » ... n motion as well as the autophagic cell death induced by the ionizing radiation. The accumulated radiation of the sequential scans allowed for the determination of a characteristic dose of autophagic vacuole formation and the lethal dose for fission yeast. The presented results demonstrate a practical method that opens another way of looking at living biological specimens and processes in a time-resolved label-free setting. Studies of nanoscale structures and dynamics of biological matter greatly benefit from observing samples in living state using label-free methods 1 . X-ray ptychography enables quantitative visualization of whole biological cells with nanoscale resolution based on the natural electron density contrast of the cell content 2-5 . An ideal eukaryotic model organism for cellular dynamic studies is fission yeast at the horsetail stage owing to the oscillations of meiotic chromosomes in the time scale of minutes to hours 6-8 . Moreover, intracellular structure changes caused by X-ray radiation are of interest for a direct analysis in situ 9 . The major challenge of X-ray imaging of living cellular specimens is the very low lethal radiation dose, and owing to the intense radiation damage and a low electron density contrast, sequential X-ray imaging of live eukaryotic cells was not possible so far 10-13 . To record sufficient information, the samples have to be exposed to a certain amount of radiation, which has to be greater than the minimum of the required dose for imaging and less than the maximum tolerable dose for the specimen 10 . The limiting factor of the resolution is therefore set by the X-ray radiation dose 10,11 . Natural, aqueous environments of biological specimens significantly decrease the electron density contrast, thus higher X-ray flux is required, which consequently increases the radiation dose needed for a given resolution 10 . Radiation induced degradation can be reduced by chemical or cryo-fixation. Using cryo-fixation, X-ray ptychography 2,4,14 and diffraction microscopy 15,16 of frozen hydrated cells were accomplished. More advanced X-ray studies were realized on living cells 17,18 and appear to be a promising approach to analyze cellular processes in situ. Imaging of initially alive cells simplifies sample preparation, owing to the fact that fixation steps are not required. Imaged living cells died during the first X-ray scan 18 or after a free electron laser (FEL) pulse 13 , due to the lethal radiation dose. However, first electron density maps measured with X-rays of initially alive bacteria, which were obtained with less than a lethal dose, were recently presented 12,19 . X-ray ptychography is a coherent diffractive imaging (CDI) technique that combines scanning microscopy with advanced phase retrieval algorithms [20] [21] [22] . It relies on scanning the extended sample by the X-ray beam, collecting 2D diffraction patterns from a number of overlapping regions of the specimen and a subsequent iterative reconstruction of a single projection image, which is consistent with all recorded diffraction patterns 21 . Published: xx xx xxxx OPEN www.nature.com/scientificreports/ 2 SCIentIfIC REPORTS | 7: 13775 |
doi:10.1038/s41598-017-13175-9 pmid:29061993 pmcid:PMC5653777 fatcat:njizaxcoyjc7jjsqc5d4vvajri

Ongoing Coxsackievirus Myocarditis Is Associated with Increased Formation and Activity of Myocardial Immunoproteasomes

Gudrun Szalay, Silke Meiners, Antje Voigt, Jörg Lauber, Christian Spieth, Nora Speer, Martina Sauter, Ulrike Kuckelkorn, Andreas Zell, Karin Klingel, Karl Stangl, Reinhard Kandolf
2006 American Journal of Pathology  
A growing body of evidence indicates that viral infections of the heart contribute to ongoing myocarditis and dilated cardiomyopathy. Murine models of coxsackievirus B3 (CVB3)-induced myocarditis mimic the human disease and allow identification of susceptibility factors that modulate the course of viral myocarditis. Susceptible mouse strains develop chronic myocarditis on the basis of restricted viral replication, whereas resistant strains recover after successful virus elimination. In
more » ... ve whole-genome microarray analyses of infected hearts, several genes involved in the processing and presentation of viral epitopes were found to be uniformly up-regulated in acutely CVB3-infected susceptible mice compared with resistant animals. In particular, expression of the catalytic subunits LMP2, LMP7, and MECL-1, immunoproteasome proteins important in the generation of major histocom-patibility complex (MHC) class I-restricted peptides, was clearly enhanced in the susceptible host. Increased expression resulted in enhanced formation of immunoproteasomes and altered proteolytic activities of proteasomes in the heart. This was accompanied by a concerted up-regulation of the antigen-presenting machinery in susceptible mice. Thus, we propose that increased formation of immunoproteasomes in susceptible mice affects the generation of antigenic peptides and the subsequent T-cell-mediated immune responses.
doi:10.2353/ajpath.2006.050865 pmid:16651621 pmcid:PMC1606581 fatcat:vbgg2zrahjdoxpjr53zciekjca

Out-of-hospital cardiac arrests in Switzerland: Predictors for emergency department mortality in patients with ROSC or on-going CPR on admission to the emergency department

Thomas C. Sauter, Nora Iten, Patrik R. Schwab, Wolf E. Hautz, Meret E. Ricklin, Aristomenis K. Exadaktylos, Andreas Schäfer
2017 PLoS ONE  
OPEN ACCESS Citation: Sauter TC, Iten N, Schwab PR, Hautz WE, Ricklin ME, Exadaktylos AK (2017) Out-of-hospital cardiac arrests in Switzerland: Predictors for emergency department mortality in patients  ...  Sauter, Patrik R. Schwab, Wolf E. Hautz, Meret E. Ricklin, Aristomenis K. Exadaktylos.  ... 
doi:10.1371/journal.pone.0188180 pmid:29145510 pmcid:PMC5690603 fatcat:ghha2ncqxjahzj3q2eclu42ate

Biocatalytic atom transfer radical polymerization in a protein cage nanoreactor

Kasper Renggli, Nora Sauter, Martin Rother, Martin G. Nussbaumer, Raphael Urbani, Thomas Pfohl, Nico Bruns
2017
doi:10.5451/unibas-ep56109 fatcat:4jjxqf4bavhl7cnbzlji3gkxfm

Single-cell lysis for visual analysis by electron microscopy

Simon Kemmerling, Stefan A Arnold, Benjamin A Bircher, Nora Sauter, Carlos Escobedo, Gregor Dernick, Andreas Hierlemann, Henning Stahlberg, Thomas Braun
2013
The stochastic nature of biological systems makes the study of individual cells a necessity in systems biology. Yet, handling and disruption of single cells and the analysis of the relatively low concentrations of their protein components still challenges available techniques. Transmission electron microscopy (TEM) allows for the analysis of proteins at the single-molecule level. Here, we present a system for single-cell lysis under light microscopy observation, followed by rapid uptake of the
more » ... ell lysate. Eukaryotic cells were grown on conductively coated glass slides and observed by light microscopy. A custom-designed microcapillary electrode was used to target and lyse individual cells with electrical pulses. Nanoliter volumes were subsequently aspirated into the microcapillary and dispensed onto an electron microscopy grid for TEM inspection. We show, that the cell lysis and preparation method conserves protein structures well and is suitable for visual analysis by TEM. (2013). Single-cell lysis for visual analysis by electron microscopy. Journal of Structural Biology, 183(3):467-73. a b s t r a c t The stochastic nature of biological systems makes the study of individual cells a necessity in systems biology. Yet, handling and disruption of single cells and the analysis of the relatively low concentrations of their protein components still challenges available techniques. Transmission electron microscopy (TEM) allows for the analysis of proteins at the single-molecule level. Here, we present a system for single-cell lysis under light microscopy observation, followed by rapid uptake of the cell lysate. Eukaryotic cells were grown on conductively coated glass slides and observed by light microscopy. A customdesigned microcapillary electrode was used to target and lyse individual cells with electrical pulses. Nanoliter volumes were subsequently aspirated into the microcapillary and dispensed onto an electron microscopy grid for TEM inspection. We show, that the cell lysis and preparation method conserves protein structures well and is suitable for visual analysis by TEM.
doi:10.5167/uzh-80940 fatcat:tlavzlcj45eohm36jw3y4otpia

Page 17 of JAOA: The Journal of the American Osteopathic Association Vol. 54, Issue 1 [page]

1954 JAOA: The Journal of the American Osteopathic Association  
Sauter, II, Speaker, presiding.)  ...  McMains, Maryland; Anna Northup-Little, Saskatchewan; Georgianna Pfeiffer, North Dakota; Nora Prather, Kentucky; A. G. Reed, Oklahoma; Phil R. Rus- sell, Texas; T. T.  ... 

Page 453 of American Annals of the Deaf Vol. 56, Issue 4 [page]

1911 American Annals of the Deaf  
—Miss Nora M. Hisey has resigned to take charge of the Toledo, Ohio, Day-School; Miss Anna L.  ...  Sauter, Miss Laura L. Arbaugh, Miss Alice Arbaugh, Miss Pauline Fisk, Miss Susan H. Norris, Miss Edna Y. Rocap, Miss Carolyn Gay Taft, and Miss Ernestine Faye Ball have resigned.  ... 

Work organization interventions: state of knowledge and future directions

Steven L. Sauter, Lawrence R. Murphy
2004 Sozial- und Präventivmedizin  
al. 2002) that was prepared under the auspices of the US National Occupational Research Agenda (NORA, http://www2.cdc.gov/NORA/default.html).  ...  In this regard, it is notable that the topic of intervention effectiveness has been recognized as a research priority under NORA, and a team of specialists from the National Institute for Occupational  ... 
doi:10.1007/s00038-004-3085-z pmid:15150855 fatcat:wshflkhhu5bnlhy6mov4q7pcge

Page 77 of JAOA: The Journal of the American Osteopathic Association Vol. 41, Issue 1 [page]

1941 JAOA: The Journal of the American Osteopathic Association  
Gibson Nora Prather |Not represented) I. J. Shalett Lester P. Gross Grace R. McMains Chas. W. Sauter, 2nd Ernest A. Marcoux Amalia Sperl E. Frank Wood Philip E. Haviland R,. K. Homan Harold D.  ... 

Page 43 of JAOA: The Journal of the American Osteopathic Association Vol. 44, Issue 1 [page]

1944 JAOA: The Journal of the American Osteopathic Association  
Gibson Nora Prather James A. Keller Roswell P. Bates Francis J. Chase Grace R. Mc Mains Alden Q. Abbott Amalia Sper! Charles W. Sauter, II Robert K. Homan Philip E. Haviland Leroy C.  ... 
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