Rafati, N., Chen, J., Herpin, A., Pettersson, M.E., Han, F., Feng, C., Wallerman, O., Rubin, C.-J., Péron, S., Cocco, A., Larssona, M., Trötschele, C., Poetsche, A., Korsching, K., Bönigk, W., Körschen, H.G., Berg, F., Folkvord, A., Kaupp, U.B., Schartl, M., and Andersson (2020). Reconstruction of the birth of a male sex chromosome present in Atlantic herring. Proc Natl Acad Sci U S A, 202009925. Link to MPG Publication Repository PuRe

Wobig, L., Wolfenstetter, T., Fechner, S., Bönigk, W., Körschen, H.G., Jikeli, J., Trötschel, C., Feederle, R., Kaupp, U.B., Seifert, R., and Berger, T.K. (2020). A family of hyperpolarization-activated channels selective for protons. Proc. Acad. Sci. USA, 202001214.Link to MPG publication database PuRe

Kaupp, U.B., Alvarez, L. (2020). Sperm as microswimmers. In: Gompper, G., Winkler, R.G., [...], Kaupp, U.B., Alvarez, L. [...], Duclos, G., Yashunsky, V., Silberzan, P., Arroyo, M. & Kale, S. (2020). The 2020 motile active matter roadmap. J Phys Condens Matter 32, 18-20 Link to MPG PuRe publication database

Schiffer, C., Rieger, S., Brenker, C., Young, S., Hamzeh, H., Wachten, D., Tüttelmann, F., Röpke, A., Kaupp, U.B., Wang, T., et al. (2020). Rotational motion and rheotaxis of human sperm do not require functional CatSper channels and transmembrane Ca2+ signaling. EMBO J. 39, e102363. Link to MPG PuRe publication database

Gong, A., Rode, S., Kaupp, U.B., Gompper, G., Elgeti, J., Friedrich, B.M., and Alvarez, L. (2020). The steering gaits of sperm. Philos Trans R Soc Lond B Biol Sci 375, 20190149. Link to MPG PuRe publication database


Trötschel, C., Hamzeh, H., Alvarez, L., Pascal, R., Lavryk, F., Bönigk, W., Körschen, H.G., Müller, A., Poetsch, A., Rennhack, A., Gui, L., Nicastro, D., Strünker, T., Seifert, R., Kaupp, U. B. (2019). Absolute proteomic quantification reveals design principles of sperm flagellar chemosensation. EMBO J., e102723. Link to MPG PuRe publication database

Gong, A., Rode, S., Kaupp, U.B., Gompper, G., Elgeti, J., Friedrich, B.M., and Alvarez, L. (2020). The steering gaits of sperm. Philos Trans R Soc Lond B Biol Sci 375, 20190149. Link to MPG PuRe publication database

Hamzeh, H., Alvarez, L., Strünker, T., Kierzek, M., Brenker, C., Deal, P.E., Miller, E.W., Seifert, R., and Kaupp, U.B. (2019). Kinetic and photonic techniques to study chemotactic signaling in sea urchin sperm. Methods Cell Biol. 151, 487-517. Link to MPG PuRe publication database


Rennhack, A., Schiffer, C., Brenker, C., Fridman, D., Nitao, E. T., Cheng, Y. M., Tamburrino, L., Balbach, M., Stölting, G., Berger, T., Kierzek, M., Alvarez, L., Wachten, D., Zeng, X. H., Baldi, E., Publicover, S., Kaupp, U. B. & Strünker, T. (2018) "A novel cross-species inhibitor to study the function of CatSper Ca 2+ channels in sperm." Br. J. Pharmacol. 175, 3144-3161 Link to MPG publication database PuRe

Windler, F., Bönigk, W., Körschen, H. G., Grahn, E., Strünker, T., Seifert, R. & Kaupp, U. B. (2018) "The solute carrier SLC9C1 is a Na+/H+-exchanger gated by an S4-type voltage-sensor and cyclic-nucleotide binding" Nature Communications 9, 2809

Brenker, C., Schiffer, C., Wagner, I.V., Tüttelmann, F., Röpke, A., Rennhack, A., Kaupp, U.B. & Strünker, T. (2018) "Action of steroids and plant triterpenoids on CatSper Ca2+ channels in human sperm” Proc. Natl. Acad. Sci. USA 115, E344–E346

Balbach, M., Beckert, V., Hansen, J.N. & Wachten, D. (2018) “Shedding light on the role of cAMP in mammalian sperm physiology” Mol. Cell. Endocrinol. 468, 111-120 Link to MPG publication database PuRe


Rennhack, A., Grahn, E., Kaupp, U.B. & Berger, T.K. (2017) “Photocontrol of the Hv1 proton channel” ACS Chem.Biol.12, 2952-2957

Saggiorato, G., Alvarez, L., Jikeli, J., Kaupp, U.B., Gompper, G. & Elgeti, J. (2017) “Human sperm steer with second harmonics of the flagellar beat” Nat. Commun. 8, 1405

Zhong, W., Ciatipis, M., Wolfenstetter, T., Jessberger, J., Müller, C., Ponsel, S., Yanovsky, Y., Brankack, J., Tort, A.B.L. & Draguhn, A. (2017) “Selective entrainment of gamma subbands by different slow network oscillations” Proc. Natl. Acad. Sci. USA 114, 4519–1524

Alvarez, L. (2017) "The tailored sperm cell" J. Plant. Res. 130, 455-464

Jansen, V., Jikeli, J.F., Wachten, D. (2017) "How to control cyclic nucleotide signaling by light" Curr. Opin. Biotechnol. 48, 15 - 20

Schonauer, S., Körschen, H.G., Penno, A., Rennhack, A., Breiden, B., Sandhoff, K., Gutbrod, K., Dörmann, P., Raju, D.N., Haberkant, P., Gerl, M.J., Brügger, B., Zigdon, H., Vardi, A., Futerman, A.H., Wachten, D. (2017) "Identification of a feedback loop involving beta-glucosidase 2 and its product sphingosine sheds light on the molecular mechanisms in Gaucher disease" J. Biol. Chem., M116.762831

Kaupp, U.B. & Strünker, T. (2016) "Signaling in sperm: more different than similar?" Trends Cell Biol. 27, 101-109

Berger, T.K., Fußhöller, D.M., Goodwin, N., Bönigk, W., Müller, A., Khesroshahi, N.D., Brenker, C., Wachten, D., Krause, E., Kaupp, U.B. & Strünker, T. (2017) "Posttranslational cleavage of Hv1 in human sperm tunes pH- and voltage-dependent gating” J. Physiol. 595, 1533-1546


Kaupp, U.B. & Alvarez, L. (2016) "Sperm as microswimmers - navigation and sensing at the physical limit" Eur. Phys. J. Spec. Top. 225, 2119-2139

Schneider, S., Balbach, M., Jikeli, J., Fietz, D., Nettersheim, D., Jostes, S., Schmidt, R., Kressin, M., Bergmann, M., Wachten, D., Steger, K. & Schorle, H. (2016) "Re-visiting the Protamine-2 locus: deletion, but not haploinsufficiency, renders male mice infertile" Sci. Rep. 6, 36764

Voß, B., Seifert, R., Kaupp, U.B. & Grubmüller, H. (2016) "A quantitative model for cAMP binding to the binding Domain of MloK1" Biophys. J. 111, 1668-1678

Wachten, D., Jikeli, J. & Kaupp, U.B. (2016) "Sperm sensory signaling" CSH Perspect. Biol., a028225

Schumacher, C.H., Körschen, H.G., Nicol, C., Gasser, C., Seifert, R., Schwarzel, M. & Moglich, A. (2016) "A Fluorometric Activity Assay for Light-Regulated Cyclic-Nucleotide-Monophosphate Actuators" Methods Mol. Biol. 1408, 93-105

Björkgren, I., Alvarez, L., Blank, N., Balbach, M., Turunen, H., Laajala, T.D., Toivanen, J., Krutskikh, A., Wahlberg, N., Huhtaniemi, I., Poutanen, M., Wachten, D. & Sipilä, P. (2016) "Targeted inactivation of the mouse epididymal beta-defensin 41 alters sperm flagellar beat pattern and zona pellucida binding" Mol. Cell. Endocrinol. 427, 143-154

Mukherjee, S., Jansen, V., Jikeli, J.F., Hamzeh, H., Alvarez, L., Dombrowski, M., Balbach, M., Strünker, T., Seifert, R., Kaupp, U.B. & Wachtern, D. (2016) "A novel biosensor to study cAMP dynamics in cilia and flagella" eLife 5, e14052


Börger, C., Schünke, S., Lecher, J., Stoldt, M., Winkhaus, F., Kaupp, U.B. & Willbold, D. (2015) "Resonance assignment of the ligand-free cyclic nucleotide-binding domain from the murine ion channel HCN2" J. Biomol. NMR 9, 243 - 246

Fechner, S., Alvarez, L., Bönigk, W., Müller, A., Berger, T., Pascal, R., Trötschel, C., Poetsch, A., Stölting, G., Siegfried, K.R., Seifert, R. & Kaupp, U.B. (2015) "A K+-selective CNG channel orchestrates Ca2+ signalling in zebrafish sperm" eLife, e07624

Royeck, M., Kelly, T., Opitz, T., Otte, D.-M., Rennhack, A., Woitecki, A., Pitsch, J., Becer, A., Schoch, S., Kaupp, U.B., Yaari, Y., Zimmer, A. & Beck, H. (2015) "Downregulation of spermine Augments dendritic persistent sodium currents and synaptic integration after status epilepticus" J. Neurosci. 35, 15240 - 15253

Jikeli, J., Alvarez, L., Friedrich, B.M., Wilson, L.G., Pascal, R., Colin, R., Pichlo, M., Rennhack, A., Brenker, C. & Kaupp, U.B. (2015) "Sperm navigation along helical paths in 3D chemoattractant landscapes" Nat. Commun. 6, 7985

Raju, D., Schonauer, S., Hamzeh, H., Flynn, K.C., Bradke, F., vom Dorp, K., Dörmann, P., Yildiz, Y., Trötschel, C., Poetsch, A., Breiden, B., Sandhoff, K., Körschen, H.G. & Wachten, D. (2015) "Accumulation of glucosylceramide in the absence of the Beta-Glucosidase GBA2 alters cytoskeletal dynamics" PLoS Genet 11, e1005063

Scheib, U., Stehfest, K., Gee, C.E., Körschen, H.G., Fudim, R., Oertner, T.G. & Hegemann, P. (2015) "The rhodopsin-guanylyl cyclase of the aquatic fungus Blastocladiella emersonii enables fast optical control of cGMP signaling" Sci. Sinal. 8, rs8

Strünker, T., Alvarez, L. & Kaupp, U.B. (2015) "At the physical limit — chemosensation in sperm" Curr. Opin. Neurobiol. 34, 110-116

Strünker, T. & Kaupp, U.B. (2015) "Larry Cohen—50 ways to DYE your science" Neurophotonics 2, 021004-021004

Mony, L., Berger, T.K. & Isacoff, E.Y. (2015) "A specialized molecular motion opens the Hv1 voltage-gated proton channel" Nat. Struct. Mol. Biol. 22, 283-290

Berger, T.K. & Isacoff, E.Y. (2015) "Fluorescent Labeling for Patch-Clamp Fluorometry (PCF) Measurements of Real-Time Protein Motion in Ion Channels" Methods Mol. Biol. 1266, 93-106

Gunkel, M., Schöneberg, J., Alkhaldi, W., Irsen, S., Noé, F., Kaupp, U.B. & Al-Amoudi, A. (2015) "Higher-order architecture of rhodopsin in intact photoreceptors and its implication for phototransduction kinetics" Structure 23, 628 - 638

Jansen, V., Alvarez, L., Balbach, M., Strünker, T., Hegemann, P., Kaupp, U.B. & Wachten, D. (2015) "Controlling fertilization and cAMP signaling in sperm by optogenetics" eLife 4, e05161

Seifert, R., Flick, M., Bönigk, W., Alvarez, L., Trötschel, C., Poetsch, A., Müller, A., Goodwin, N., Pelzer, P., Kashikar, N.D., Kremmer, E., Jikeli, J., Timmermann, B., Kuhl, H., Fridman, D., Windler, F., Kaupp, U.B. & Strünker, T. (2015) "The CatSper channel controls chemosensation in sea urchin sperm" EMBO J. 34, 379-392


Börger, C., Schünke, S., Lecher, J., Stoldt, M., Winkhaus, F., Kaupp, U.B. & Willbold, D. (2014) "Resonance assignment of the ligand-free cyclic nucleotide-binding domain from the murine ion channel HCN2" Biomol. NMR Assign. 9, 243-246

Pichlo, M., Bungert-Plümke, S., Weyand, I., Seifert, R., Bönigk, W., Strünker, T., Kashikar, N.D., Goodwin, N., Müller, A., Pelzer, P., Van, Q., Enderlein, J., Klemm, C., Krause, E., Trotschel, C., Poetsch, A., Kremmer, E. & Kaupp, U.B. (2014) "High density and ligand affinity confer ultrasensitive signal detection by a guanylyl cyclase chemoreceptor" J. Cell. Biol. 206, 541-557

Schiffer, C., Müller, A., Egeberg, D.L., Alvarez, L., Brenker, C., Rehfeld, A., Frederiksen, H., Wäschle, B., Kaupp, U.B., Balbach, M., Wachten, D., Skakkebaek, N.E., Almstrup, K. & Strünker, T. (2014) "Direct action of endocrine disrupting chemicals on human sperm" EMBO Rep. 15, 731-815

Brenker, C., Zhou, Y., Müller, A., Echeverry, F.A., Trotschel, C., Poetsch, A., Xia, X.M., Bönigk, W., Lingle, C.J., Kaupp, U.B. & Strünker, T. (2014) "The Ca2+-activated K+ current of human sperm is mediated by Slo3" eLife 3, e01438

Mass, E., Wachten, D., Aschenbrenner, A.C., Voelzmann, A. & Hoch, M. (2014) "Murine Creld1 Controls Cardiac Development through Activation of Calcineurin/NFATc1 Signaling" Dev. Cell 28, 711-726

Alvarez, L., Friedrich, B.M., Gompper, G. & Kaupp, U.B. (2014) "The computational sperm cell" Trends Cell Biol. 24, 198-207


Geißler, K.J., Jung, M.J., Riecken, L.B., Sperka, T., Cui, Y., Schacke, S., Merkel, U., Markwart, R., Rubio, I., Than, M.E., Breithaupt, C., Peuker, S., Seifert, R., Kaupp, U.B., Herrlich, P. & Morrison, H. (2013) "Regulation of Son of sevenless by the membrane-actin linker protein ezrin" Proc. Natl. Acad. Sci. USA 110, 20587-20592

Krähling, M., Alvarez, L., Debowski, K., Van, Q., Gunkel, M., Irsen, S., Al-Amoudi, A., Strünker, T., Kremmer, E., Krause, E., Voigt, I., Wörtge, S., Waisman, A., Weyand, I., Seifert, R., Kaupp, U.B. & Wachten, D. (2013) "CRIS- a novel cAMP-binding protein controlling spermiogenesis and the development of flagellar bending" PLoS Genet.9, e1003960

Rabionet, M., Bayerle, A., Marsching, C., Jennemann, R., Grone, H.J., Yildiz, Y., Wachten, D., Shaw, W., Shayman, J.A. & Sandhoff, R. (2013) "1-O-Acylceramides are natural components of human and mouse epidermis" J. Lipid. Res. 54, 3312-3321

Hirohashi, N., Alvarez, L., Shiba, K., Fujiwara, E., Iwata, Y., Mohri, T., Inaba, K., Chiba, K., Ochi, H., Supuran, C.T., Kotzur, N., Kakiuchi, Y., Kaupp, U.B. & Baba, S.A. (2013) "Sperm from Sneaker Male Squids Exhibit Chemotactic Swarming to CO2" Curr. Biol. 23, 775-781

Peuker, S., Cukkemane, A., Held, M., Noé, F., Kaupp, U.B. & Seifert, R. (2013) "Kinetics of ligand-receptor interaction reveals an induced-fit mode of binding in a cyclic nucleotide-activated protein" Biophys. J. 104, 63-74

Körschen, H.G., Yildiz, Y., Raju, D.N., Schonauer, S., Bönigk, W., Jansen, V., Kremmer, E., Kaupp, U.B. & Wachten, D. (2013) "The non-lysosomal beta-glucosidase GBA2 is a non-integral membrane-associated protein at the ER and Golgi" J. Biol. Chem. 288, 3388-3393


Alvarez, L., Dai, L., Friedrich, B.M., Kashikar, N., Gregor, I., Pascal, R. & Kaupp, U.B. (2012) "The rate of change in Ca 2+ concentration controls sperm chemotaxis" J. Cell Biol. 196, 653-663

Brenker, C., Goodwin, N., Weyand, I., Kashikar, N.D., Naruse, M., Krähling, M., Müller, A., Kaupp, U.B. & Strünker, T. (2012) "The CatSper channel: a polymodal chemosensor in human sperm" EMBO J. 31, 1654-1665

Cukkemane, A., Nand, D., Gradmann, S., Weingarth, M., Kaupp, U.B. & Baldus, M. (2012) "Solid-state NMR [ [++13)C, (15)N] resonance assignments of the nucleotide-binding domain of a bacterial cyclic nucleotide-gated channel" Biomol. NMR Assign. 6, 225-229

Drawnel, F.M., Wachten, D., Molkentin, J.D., Maillet, M., Aronsen, J.M., Swift, F., Sjaastad, I., Liu, N., Catalucci, D., Mikoshiba, K., Hisatsune, C., Okkenhaug, H., Andrews, S.R., Bootman, M.D. & Roderick, H.L. (2012) "Mutual antagonism between IP3RII and miRNA-133a regulates calcium signals and cardiac hypertrophy" J. Cell Biol. 199, 783-798

Kashikar, N.D., Alvarez, L., Seifert, R., Gregor, I., Jäckle, O., Beyermann, M., Krause, E. & Kaupp, U.B. (2012) "Temporal sampling, resetting, and adaptation orchestrate gradient sensing in sperm" J. Cell Biol. 198, 1075-1091

Kaupp, U.B. (2012) "100 years of sperm chemotaxis" J. Gen. Physiol. 140, 583-586

Kusch, J., Thon, S., Schulz, E., Biskup, C., Nache, V., Zimmer, T., Seifert, R., Schwede, F. & Benndorf, K. (2012) "How subunits cooperate in cAMP-induces activation of homotetrameric HCN2 channels" Nature Chem. Biol. 8, 162-169

Nache, V., Zimmer, T., Wongsamitkul, N., Schmauder, R., Kusch, J., Reinhardt, L., Bönigk, W., Seifert, R., Biskup, C., Schwede, F. & Benndorf, K. (2012) "Differential regulation by cyclic nucleotides of the CNGA4 and CNGB1b subunits in olfactory cyclic nucleotide-gated channels" Sci. Signal. 5, ra48

Strünker, T. (2012) "A unique K+-selective ion channel activated by a single cGMP molecule controls chemotaxis of sea urchin sperm" In: Morisawa, M. (ed.): Sperm Cell Research in the 21st Century: Historical Discoveries to New Horizons (Tokyo: Adthree Publishing Co.m Ltd), 142-145


Cukkemane, A., Seifert, R. & Kaupp, U.B. (2011) "Cooperative and uncooperative cyclic-nucleotide-gated ion channels" Trends Biochem. Sci. 36, 55-64

Elgeti, J., Kaupp, U.B. & Gompper, G. "Response to comment on article: hydrodynamics of sperm cells near surfaces" (2011) Biophys. J. 100, 2321-2324

Friedrich, B.M. & Kaupp, U.B. (2011) "Eine schwimmende Sinneszelle" Phys. in unserer Zeit 42, 196-200

Harzheim, D., Roderick, H.L. & Bootman, M.D. (2011) "Intracellular calcium signaling" In: Bradshaw, R.A. & Dennis, E.A. (eds.): Functioning of transmembrane receptors in cell signaling mechanisms (Amsterdam: Academic Press), 377-382

Schünke, S., Stoldt, M., Lecher, J., Kaupp, U.B. & Willbold, D. (2011) "Structural insights into conformational changes of a cyclic nucleotide-binding domain in solution from Mesorhizobium loti K1 channel" Proc. Natl. Acad. Sci. USA 108, 6121-6126

Strünker, T., Goodwin, N., Brenker, C., Kashikar, N.D., Weyand, I., Seifert, R. & Kaupp, U.B. (2011) "The CatSper channel mediates progesterone-induced Ca 2+ influx in human sperm" Nature 471, 382-386


Elgeti, J., Kaupp, U.B. & Gompper, G. (2010) "Hydrodynamics of sperm cells near surfaces" Biophys. J. 99, 1018-1026

Fried, H.U., Kaupp, U.B. & Müller, F. (2010) "Hyperpolarization-activated and cyclic nucleotide-gated channels are differentially expressed in juxtaglomerular cells in the olfactory bulb of mice" Cell Tissue Res. 339, 463-479

Georgiev, P., Okkenhaug, H., Drews, A., Wright, D., Lambert, S., Flick, M., Carta, V., Martel, C., Oberwinkler, J. & Raghu, P. (2010) "TRPM channels mediate zinc homeostasis and cellular growth during Drosophila larval development" Cell Metab. 12, 386-397

Harzheim, D., Talasila, A., Movassagh, M., Foo, R.S., Figg, N., Bootman, M.D. & Roderick, H.L. (2010) "Elevated InsP 3R expression underlies enhanced calcium fluxes and spontaneous extra-systolic calcium release events in hypertrophic cardiac myocytes" Channels (Austin) 4, 67-71

Kaupp, U.B. (2010) "Olfactory signalling in vertebrates and insects: differences and commonalities" Nat. Rev. Neurosci. 11, 188-200

Schünke, S., Lecher, J., Stoldt, M., Kaupp, U.B. & Willbold, D. (2010) "Resonance assignments of the nucleotide-free wildtype MloK1 cyclic nucleotide-binding domain" Biomol. NMR Assign. 4, 147-150

Smyrnias, I., Mair, W., Harzheim, D., Walker, S.A., Roderick, H.L. & Bootman, M.D. (2010) "Comparison of the T-tubule system in adult rat ventricular and atrial myocytes, and its role in excitation-contraction coupling and inotropic stimulation" Cell Calcium 47, 210-223


Bönigk, W., Loogen, A., Seifert, R., Kashikar, N., Klemm, C., Krause, E., Hagen, V., Kremmer, E., Strünker, T. & Kaupp, U.B. (2009) "An atypical CNG channel activated by a single cGMP molecule controls sperm chemotaxis" Sci. Signal. 2, ra68

Fleissner, M.R., Brustad, E.M., Kálai, T., Altenbach, C., Cascio, D., Peters, F.B., Hideg, K., Peuker, S., Schultz, P.G. & Hubbell, W.L. (2009) "Site-directed spin labeling of a genetically encoded unnatural amino acid" Proc. Natl. Acad. Sci. USA 106, 21637-21642

Harzheim, D., Movassagh, M., Foo, R.S., Ritter, O., Tashfeen, A., Conway, S.J., Bootman, M.D. & Roderick, H.L. (2009) "Increased InsP3Rs in the junctional sarcoplasmic reticulum augment Ca 2+ transients and arrhythmias associated with cardiac hypertrophy" Proc. Natl. Acad. Sci. USA 106, 11406-11411

Kilic, F., Kashikar, N.D., Schmidt, R., Alvarez, L., Dai, L., Weyand, I., Wiesner, B., Goodwin, N., Hagen, V. & Kaupp, U.B. (2009) "Caged progesterone: a new tool for studying rapid nongenomic actions of progesterone" J. Am. Chem. Soc. 131, 4027-4030

Schünke, S., Stoldt, M., Novak, K., Kaupp, U.B. & Willbold, D. (2009) "Solution structure of the Mesorhizobium loti K1 channel cyclic nucleotide-binding domain in complex with cAMP" EMBO Rep. 10, 729-735


Harzheim, D., Seifert, R., Pfeiffer, K.H., Fabritz, L., Kremmer, E., Buch, T., Waisman, A., Kirchhof, P. & Kaupp, U.B. (2008) "Cardiac pacemaker function of HCN4 channels is confined to embryonic development and requires cyclic AMP" EMBO J. 27, 692-703

Kaupp, U.B., Kashikar, N. & Weyand, I. (2008) "Mechanisms of sperm chemotaxis" Ann. Rev. Physiol. 70, 93-117

Knop, G.C., Seeliger, M.W., Thiel, F., Mataruga, A., Kaupp, U.B., Friedburg, C., Tanimoto, N. & Müller, F. (2008) "Light responses in the mouse retina are prolonged upon targeted deletion of the HCN1 channel gene" Eur. J. Neurosci. 28, 2221-2230

Löer, B. & Hoch, M. (2008) "Wech proteins: roles in integrin functions and beyond" Cell Adh. Migr. 2, 177-179