Search

Your search keyword '"Hegemann, Peter"' showing total 1,087 results
Start Over Author "Hegemann, Peter"
1,087 results on '"Hegemann, Peter"'

3. Author Correction: MerMAIDs: a family of metagenomically discovered marine anion-conducting and intensely desensitizing channelrhodopsins

Author

Oppermann, Johannes, Fischer, Paul, Silapetere, Arita, Liepe, Bernhard, Rodriguez-Rozada, Silvia, Flores-Uribe, José, Schiewer, Enrico, Keidel, Anke, Vierock, Johannes, Kaufmann, Joel, Broser, Matthias, Luck, Meike, Bartl, Franz, Hildebrandt, Peter, Wiegert, J. Simon, Béjà, Oded, Hegemann, Peter, and Wietek, Jonas

Published
2024
Full Text
View/download PDF

4. Light-regulated adsorption and desorption of Chlamydomonas cells at surfaces

Author

Catalan, Rodrigo E., Fragkopoulos, Alexandros A., von Trott, Nicolas, Kelterborn, Simon, Baidukova, Olga, Hegemann, Peter, and Bäumchen, Oliver

Subjects
Physics - Biological Physics, Condensed Matter - Soft Condensed Matter, Condensed Matter - Statistical Mechanics
Abstract

Microbial colonization of surfaces represents the first step towards biofilm formation, which is a recurring phenomenon in nature with beneficial and detrimental implications in technological and medical settings. Consequently, there is a current interest in elucidating the fundamental aspects of the initial stages of biofilm formation of microorganisms on solid surfaces. While most of the research is oriented to understand bacterial surface colonization, such observations at a fundamental level using photosynthetic microalgae are thus far elusive. Recent single-cell studies showed that the flagellar adhesion of Chlamydomonas is switched on in blue light and switched off under red light [Kreis et al., Nature Physics, 2018, 14, 45-49]. Here, we study this light-switchable surface association of C. reinhardtii on the population level and measure the kinetics of adsorption and desorption of suspensions of motile cells on glass surfaces using bright field optical microscopy. We observe that both processes exhibit a response lag relative to the time at which the blue- and red-light conditions are set and model this feature using time-delayed Langmuir-type kinetics. We find that cell adsorption occurs significantly faster than desorption, which we attribute to the protein-mediated molecular adhesion mechanism of the cells. Adsorption experiments using phototactically blind Chlamydomonas mutants demonstrate that phototaxis does not affect the cell adsorption kinetics. Hence, this method can be used as an assay for characterizing the dynamics of the surface colonization of microbial species exhibiting light-regulated surface adhesion., Comment: 10, pages, 6 figures

Published
2022
Full Text
View/download PDF

6. Tip-Enhanced Infrared Difference-Nanospectroscopy of the Proton Pump Activity of Bacteriorhodopsin in Single Purple Membrane Patches

Author

Giliberti, Valeria, Polito, Raffaella, Ritter, Eglof, Broser, Matthias, Hegemann, Peter, Puskar, Ljiljana, Schade, Ulrich, Zanetti-Polzi, Laura, Daidone, Isabella, Corni, Stefano, Rusconi, Francesco, Biagioni, Paolo, Baldassarre, Leonetta, and Ortolani, Michele

Subjects
Physics - Biological Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Optics
Abstract

Photosensitive proteins embedded in the cell membrane (about 5 nm thickness) act as photoactivated proton pumps, ion gates, enzymes, or more generally, as initiators of stimuli for the cell activity. They are composed of a protein backbone and a covalently bound cofactor (e.g. the retinal chromophore in bacteriorhodopsin (BR), channel rhodopsin, and other opsins). The light-induced conformational changes of both the cofactor and the protein are at the basis of the physiological functions of photosensitive proteins. Despite the dramatic development of microscopy techniques, investigating conformational changes of proteins at the membrane monolayer level is still a big challenge. Techniques based on atomic force microscopy (AFM) can detect electric currents through protein monolayers and even molecular binding forces in single-protein molecules but not the conformational changes. For the latter, Fourier-transform infrared spectroscopy (FTIR) using difference-spectroscopy mode is typically employed, but it is performed on macroscopic liquid suspensions or thick films containing large amounts of purified photosensitive proteins. In this work, we develop AFM-assisted, tip-enhanced infrared difference-nanospectroscopy to investigate light-induced conformational changes of the bacteriorhodopsin mutant D96N in single submicrometric native purple membrane patches. We obtain a significant improvement compared with the signal-to-noise ratio of standard IR nanospectroscopy techniques by exploiting the field enhancement in the plasmonic nanogap that forms between a gold-coated AFM probe tip and an ultraflat gold surface, as further supported by electromagnetic and thermal simulations. IR difference-spectra in the 1450-1800 cm^{-1} range are recorded from individual patches as thin as 10 nm, with a diameter of less than 500 nm, well beyond the diffraction limit for FTIR microspectroscopy..., Comment: published under ACS AuthorChoice license

Published
2019
Full Text
View/download PDF

10. List of contributors

Author

Alric, Jean, primary, Atteia, Ariane, additional, Bailleul, Benjamin, additional, Ball, Steven G., additional, Benning, Christoph, additional, Blaby-Haas, Crysten E., additional, Bohne, Alexandra-Viola, additional, Boisset, Nicolas D., additional, Buchert, Felix, additional, Caccamo, Anna, additional, Calatrava, Victoria, additional, Cardol, Pierre, additional, Choquet, Yves, additional, Croce, Roberta, additional, Croteau, Dany, additional, Crozet, Pierre, additional, Danon, Antoine, additional, Dauvillée, David, additional, de Carpentier, Félix, additional, Deschamps, Philippe, additional, deVitry, Catherine, additional, Drouard, Laurence, additional, Duanmu, Deqiang, additional, Engel, Benjamin D., additional, Fernandez, Emilio, additional, Galvan, Aurora, additional, Goldschmidt-Clermont, Michel, additional, Gonzalez-Halphen, Diego, additional, Grossman, Arthur R., additional, Hamel, Patrice P., additional, Happe, Thomas, additional, Hauser, Charles, additional, Hegemann, Peter, additional, Hemschemeier, Anja, additional, Henri, Julien, additional, Hippler, Michael, additional, Iwai, Masakazu, additional, Johnson, Xenie, additional, Lagarias, J. Clark, additional, Le Moigne, Théo, additional, Lemaire, Stéphane D., additional, Li-Beisson, Yonghua, additional, Lohr, Martin, additional, Mackinder, Luke C.M., additional, Marchand, Christophe H., additional, Merchant, Sabeeha S., additional, Nickelsen, Joerg, additional, Niyogi, Krishna K., additional, Posewitz, Matthew C., additional, Przybyla-Toscano, Jonathan, additional, Redding, Kevin E., additional, Remacle, Claire, additional, Riekhof, Wayne, additional, Rochaix, Jean-David, additional, Rouhier, Nicolas, additional, Salinas-Giegé, Thalia, additional, Santabarbara, Stefano, additional, Sanz-Luque, Emanuel, additional, Scholz, Martin, additional, Schroda, Michael, additional, Subrahmanian, Nitya, additional, Takahashi, Yuichiro, additional, Tejada-Jimenez, Manuel, additional, Vierock, Johannes, additional, Wakao, Setsuko, additional, Warakanont, Jaruswan, additional, Wietrzynski, Wojciech, additional, Willmund, Felix, additional, Willows, Robert D., additional, Wollman, Francis-André, additional, Wostrikoff, Katia, additional, Zerges, William, additional, Zinzius, Karen, additional, and Zito, Francesca, additional

Published
2023
Full Text
View/download PDF

12. List of contributors

Author

Alford, Lea M., primary, Avasthi, Prachee, additional, Awasthi, Mayanka, additional, Bayly, Philip V., additional, Bloodgood, Robert A., additional, Brown, Alan, additional, Bui, Khanh Huy, additional, Cortese, Dario, additional, Dieckmann, Carol, additional, Diener, Dennis, additional, Dutcher, Susan K., additional, Guichard, Paul, additional, Hamel, Virginie, additional, Hegemann, Peter, additional, Hirono, Masafumi, additional, Kamiya, Ritsu, additional, King, Stephen M., additional, Kreimer, Georg, additional, Lechtreck, Karl, additional, Lefebvre, Paul A., additional, Lorentzen, Esben, additional, Mahjoub, Moe R., additional, Mitchell, David R., additional, Nicastro, Daniela, additional, Onishi, Masayuki, additional, Pan, Junmin, additional, Porter, Mary E., additional, Quarmby, Lynne M., additional, Ranjan, Peeyush, additional, Sale, Winfield S., additional, Snell, William J., additional, Wakabayashi, Ken-ichi, additional, Wan, Kirsty Y., additional, Wirschell, Maureen, additional, Witman, George B., additional, Woodhams, Louis G., additional, Yagi, Toshiki, additional, Yamamoto, Ryosuke, additional, Yang, Pinfen, additional, and Zhao, Yanhe, additional

Published
2023
Full Text
View/download PDF

13. List of contributors

Author

Baidukova, Olga, primary, Blaby, Ian K., additional, Blaby-Haas, Crysten E., additional, Breker-Dekel, Michal, additional, Craig, Rory J., additional, Darienko, Tatyana, additional, Dutcher, Susan K., additional, Engel, Benjamin D., additional, Glaesener, Anne G., additional, Goodenough, Ursula, additional, Hegemann, Peter, additional, Hui, Colleen, additional, Joo, Sunjoo, additional, Kelterborn, Simon, additional, Kobayashi, Yusuke, additional, Lee, Jae-Hyeok, additional, Li, Xiaobo, additional, Liu, Dianyi, additional, Mackinder, Luke C.M., additional, Miller, Stephen M., additional, Nishimura, Yoshiki, additional, Nozaki, Hisayoshi, additional, Pröschold, Thomas, additional, Schmollinger, Stefan, additional, Silflow, Carolyn D., additional, Sizova, Irina, additional, Snell, William J., additional, Soto, Maria J., additional, Stormo, Gary D., additional, Tulin, Frej, additional, Umen, James, additional, Vallon, Olivier, additional, Wang, Yulong, additional, Weeks, Donald P., additional, Wingfield, Jenna, additional, and Yang, Yuqing, additional

Published
2023
Full Text
View/download PDF

15. Reverse genetics

Author

Baidukova, Olga, primary, Kelterborn, Simon, additional, Sizova, Irina, additional, and Hegemann, Peter, additional

Published
2023
Full Text
View/download PDF

17. Rhodopsin-bestrophin fusion proteins from unicellular algae form gigantic pentameric ion channels

Author

Rozenberg, Andrey, Kaczmarczyk, Igor, Matzov, Donna, Vierock, Johannes, Nagata, Takashi, Sugiura, Masahiro, Katayama, Kota, Kawasaki, Yuma, Konno, Masae, Nagasaka, Yujiro, Aoyama, Mako, Das, Ishita, Pahima, Efrat, Church, Jonathan, Adam, Suliman, Borin, Veniamin A., Chazan, Ariel, Augustin, Sandra, Wietek, Jonas, Dine, Julien, Peleg, Yoav, Kawanabe, Akira, Fujiwara, Yuichiro, Yizhar, Ofer, Sheves, Mordechai, Schapiro, Igor, Furutani, Yuji, Kandori, Hideki, Inoue, Keiichi, Hegemann, Peter, Béjà, Oded, and Shalev-Benami, Moran

Published
2022
Full Text
View/download PDF

18. Potassium channel-based optogenetic silencing

Author

Bernal Sierra, Yinth Andrea, Rost, Benjamin R, Pofahl, Martin, Fernandes, António Miguel, Kopton, Ramona A, Moser, Sylvain, Holtkamp, Dominik, Masala, Nicola, Beed, Prateep, Tukker, John J, Oldani, Silvia, Bönigk, Wolfgang, Kohl, Peter, Baier, Herwig, Schneider-Warme, Franziska, Hegemann, Peter, Beck, Heinz, Seifert, Reinhard, and Schmitz, Dietmar

Subjects
Biomedical and Clinical Sciences, Neurosciences, Genetics, Adenylyl Cyclases, Animals, Animals, Genetically Modified, Channelrhodopsins, Gene Expression, HEK293 Cells, Humans, Light, Mice, Models, Animal, Myocytes, Cardiac, Neurons, Optogenetics, Potassium Channels, Rhodopsin, Silencer Elements, Transcriptional, Zebrafish
Abstract

Optogenetics enables manipulation of biological processes with light at high spatio-temporal resolution to control the behavior of cells, networks, or even whole animals. In contrast to the performance of excitatory rhodopsins, the effectiveness of inhibitory optogenetic tools is still insufficient. Here we report a two-component optical silencer system comprising photoactivated adenylyl cyclases (PACs) and the small cyclic nucleotide-gated potassium channel SthK. Activation of this 'PAC-K' silencer by brief pulses of low-intensity blue light causes robust and reversible silencing of cardiomyocyte excitation and neuronal firing. In vivo expression of PAC-K in mouse and zebrafish neurons is well tolerated, where blue light inhibits neuronal activity and blocks motor responses. In combination with red-light absorbing channelrhodopsins, the distinct action spectra of PACs allow independent bimodal control of neuronal activity. PAC-K represents a reliable optogenetic silencer with intrinsic amplification for sustained potassium-mediated hyperpolarization, conferring high operational light sensitivity to the cells of interest.

Published
2018

28. Insights into degradation and targeting of the photoreceptor channelrhodopsin‐1.

Author

Wolfram, Michaela, Greif, Arne, Baidukova, Olga, Voll, Hildegard, Tauber, Sandra, Lindacher, Jana, Hegemann, Peter, and Kreimer, Georg

Subjects
CYSTEINE proteinases, CYCLIC adenylic acid, EXTRACELLULAR vesicles, CHLAMYDOMONAS, CELL membranes
Abstract

In Chlamydomonas, the directly light‐gated, plasma membrane‐localized cation channels channelrhodopsins ChR1 and ChR2 are the primary photoreceptors for phototaxis. Their targeting and abundance is essential for optimal movement responses. However, our knowledge how Chlamydomonas achieves this is still at its infancy. Here we show that ChR1 internalization occurs via light‐stimulated endocytosis. Prior or during endocytosis ChR1 is modified and forms high molecular mass complexes. These are the solely detectable ChR1 forms in extracellular vesicles and their abundance therein dynamically changes upon illumination. The ChR1‐containing extracellular vesicles are secreted via the plasma membrane and/or the ciliary base. In line with this, ciliogenesis mutants exhibit increased ChR1 degradation rates. Further, we establish involvement of the cysteine protease CEP1, a member of the papain‐type C1A subfamily. ΔCEP1‐knockout strains lack light‐induced ChR1 degradation, whereas ChR2 degradation was unaffected. Low light stimulates CEP1 expression, which is regulated via phototropin, a SPA1 E3 ubiquitin ligase and cyclic AMP. Further, mutant and inhibitor analyses revealed involvement of the small GTPase ARL11 and SUMOylation in ChR1 targeting to the eyespot and cilia. Our study thus defines the degradation pathway of this central photoreceptor of Chlamydomonas and identifies novel elements involved in its homoeostasis and targeting. Summary Statement: How Chlamydomonas targets and controls the level of its main photoreceptor for photomovement responses is largely unknown. Here we show involvement of light‐stimulated endocytosis, cilia, a small GTPase, and a phototropin E3 ubiquitin ligase‐ and cAMP‐controlled cysteine protease in these processes. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

32. Cytokinin‐deficient Chlamydomonas reinhardtii CRISPR‐Cas9 mutants show reduced ability to prime resistance of tobacco against bacterial infection

Author

Sandor, Roman, primary, Wagh, Sopan Ganpatrao, additional, Kelterborn, Simon, additional, Großkinsky, Dominik K., additional, Novak, Ondrej, additional, Olsen, Niels, additional, Paul, Bichitra, additional, Petřík, Ivan, additional, Wu, Shujie, additional, Hegemann, Peter, additional, Strnad, Miroslav, additional, Červený, Jan, additional, and Roitsch, Thomas, additional

Published
2024
Full Text
View/download PDF

35. Cytokinin-deficient Chlamydomonas reinhardtii CRISPR-Cas9 mutants show reduced ability to prime resistance of tobacco against bacterial infection

Author

Sandor, Roman, Wagh, Sopan Ganpatrao, Kelterborn, Simon, Großkinsky, Dominik K., Novak, Ondrej, Olsen, Niels, Paul, Bichitra, Petřík, Ivan, Wu, Shujie, Hegemann, Peter, Strnad, Miroslav, Červený, Jan, Roitsch, Thomas, Sandor, Roman, Wagh, Sopan Ganpatrao, Kelterborn, Simon, Großkinsky, Dominik K., Novak, Ondrej, Olsen, Niels, Paul, Bichitra, Petřík, Ivan, Wu, Shujie, Hegemann, Peter, Strnad, Miroslav, Červený, Jan, and Roitsch, Thomas

Abstract

Although microalgae have only recently been recognized as part of the plant and soil microbiome, their application as biofertilizers has a tradition in sustainable crop production. Under consideration of their ability to produce the plant growth-stimulating hormone cytokinin (CK), known to also induce pathogen resistance, we have assessed the biocontrol ability of CK-producing microalgae. All pro- and eukaryotic CK-producing microalgae tested were able to enhance the tolerance of tobacco against Pseudomonas syringae pv. tabaci (PsT) infection. Since Chlamydomonas reinhardtii (Cre) proved to be the most efficient, we functionally characterized its biocontrol ability. We employed the CRISPR-Cas9 system to generate the first knockouts of CK biosynthetic genes in microalgae. Specifically, we targeted Cre Lonely Guy (LOG) and isopentenyltransferase (IPT) genes, the key genes of CK biosynthesis. While Cre wild-type exhibits a strong protection, the CK-deficient mutants have a reduced ability to induce plant defence. The degree of protection correlates with the CK levels, with the IPT mutants showing less protection than the LOG mutants. Gene expression analyses showed that Cre strongly stimulates tobacco resistance through defence gene priming. This study functionally verifies that Cre primes defence responses with CK, which contributes to the robustness of the effect. This work contributes to elucidate microalgae-mediated plant defence priming and identifies the role of CKs. In addition, these results underscore the potential of CK-producing microalgae as biologicals in agriculture by combining biofertilizer and biocontrol ability for sustainable and environment-friendly crop management.

Published
2024

36. Optogenetics: 10 years after ChR2 in neurons—views from the community

Author

Adamantidis, Antoine, Arber, Silvia, Bains, Jaideep S, Bamberg, Ernst, Bonci, Antonello, Buzsáki, György, Cardin, Jessica A, Costa, Rui M, Dan, Yang, Goda, Yukiko, Graybiel, Ann M, Häusser, Michael, Hegemann, Peter, Huguenard, John R, Insel, Thomas R, Janak, Patricia H, Johnston, Daniel, Josselyn, Sheena A, Koch, Christof, Kreitzer, Anatol C, Lüscher, Christian, Malenka, Robert C, Miesenböck, Gero, Nagel, Georg, Roska, Botond, Schnitzer, Mark J, Shenoy, Krishna V, Soltesz, Ivan, Sternson, Scott M, Tsien, Richard W, Tsien, Roger Y, Turrigiano, Gina G, Tye, Kay M, and Wilson, Rachel I

Subjects
Biomedical and Clinical Sciences, Neurosciences, Action Potentials, Animals, Channelrhodopsins, Humans, Neurons, Optogenetics, Psychology, Cognitive Sciences, Neurology & Neurosurgery, Biological psychology
Published
2015

40. Phototropin connects blue light perception to starch metabolism in green algae

Author

Yuan, Yizhong, primary, Iannetta, Anthony A, additional, Kim, Minjae, additional, Sadecki, Patric W., additional, Arend, Marius, additional, Tsichla, Angeliki, additional, Ruiz-Sola, M. Águila, additional, Kepesidis, Georgios, additional, Falconet, Denis, additional, Thevenon, Emmanuel, additional, Tardif, Marianne, additional, Brugière, Sabine, additional, Couté, Yohann, additional, Kleman, Jean Philippe, additional, Sizova, Irina, additional, Schilling, Marion, additional, Jouhet, Juliette, additional, Hegemann, Peter, additional, Li-Beisson, Yonghua, additional, Nikoloski, Zoran, additional, Bastien, Olivier, additional, Hicks, Leslie M., additional, and Petroutsos, Dimitris, additional

Published
2024
Full Text
View/download PDF

41. BiPOLES is an optogenetic tool developed for bidirectional dual-color control of neurons

Author

Vierock, Johannes, Rodriguez-Rozada, Silvia, Dieter, Alexander, Pieper, Florian, Sims, Ruth, Tenedini, Federico, Bergs, Amelie C. F., Bendifallah, Imane, Zhou, Fangmin, Zeitzschel, Nadja, Ahlbeck, Joachim, Augustin, Sandra, Sauter, Kathrin, Papagiakoumou, Eirini, Gottschalk, Alexander, Soba, Peter, Emiliani, Valentina, Engel, Andreas K., Hegemann, Peter, and Wiegert, J. Simon

Published
2021
Full Text
View/download PDF

46. Experimental Assessment of the Electronic and Geometrical Structure of a Near-Infrared Absorbing and Highly Fluorescent Microbial Rhodopsin

Author

Broser, Matthias, primary, Andruniów, Tadeusz, additional, Kraskov, Anastasia, additional, Palombo, Riccardo, additional, Katz, Sagie, additional, Kloz, Miroslav, additional, Dostál, Jakub, additional, Bernardo, César, additional, Kennis, John T. M., additional, Hegemann, Peter, additional, Olivucci, Massimo, additional, and Hildebrandt, Peter, additional

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results