Honors & Awards

  • postdoctoral fellowship, Deutscher Akademischer Austauschdienst (DAAD) (1.1.2012-12.31.2012)

Professional Education

  • Diplom Biologe, University of Cologne, Neurobiology (2007)
  • Doctor of Philosophy, Georg August Universitat Gottingen (2011)

Stanford Advisors


Graduate and Fellowship Programs


All Publications

  • Designer aminoglycosides prevent cochlear hair cell loss and hearing loss JOURNAL OF CLINICAL INVESTIGATION Huth, M. E., Han, K., Sotoudeh, K., Hsieh, Y., Effertz, T., Vu, A. A., Verhoeven, S., Hsieh, M. H., Greenhouse, R., Cheng, A. G., Ricci, A. J. 2015; 125 (2): 583-592


    Bacterial infections represent a rapidly growing challenge to human health. Aminoglycosides are widely used broad-spectrum antibiotics, but they inflict permanent hearing loss in up to ~50% of patients by causing selective sensory hair cell loss. Here, we hypothesized that reducing aminoglycoside entry into hair cells via mechanotransducer channels would reduce ototoxicity, and therefore we synthesized 9 aminoglycosides with modifications based on biophysical properties of the hair cell mechanotransducer channel and interactions between aminoglycosides and the bacterial ribosome. Compared with the parent aminoglycoside sisomicin, all 9 derivatives displayed no or reduced ototoxicity, with the lead compound N1MS 17 times less ototoxic and with reduced penetration of hair cell mechanotransducer channels in rat cochlear cultures. Both N1MS and sisomicin suppressed growth of E. coli and K. pneumoniae, with N1MS exhibiting superior activity against extended spectrum β lactamase producers, despite diminished activity against P. aeruginosa and S. aureus. Moreover, systemic sisomicin treatment of mice resulted in 75% to 85% hair cell loss and profound hearing loss, whereas N1MS treatment preserved both hair cells and hearing. Finally, in mice with E. coli-infected bladders, systemic N1MS treatment eliminated bacteria from urinary tract tissues and serially collected urine samples, without compromising auditory and kidney functions. Together, our findings establish N1MS as a nonototoxic aminoglycoside and support targeted modification as a promising approach to generating nonototoxic antibiotics.

    View details for DOI 10.1172/JCI77424

    View details for Web of Science ID 000348962700017

  • The how and why of identifying the hair cell mechano-electrical transduction channel PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY Effertz, T., Scharr, A. L., Ricci, A. J. 2015; 467 (1): 73-84


    Identification of the auditory hair cell mechano-electrical transduction (hcMET) channel has been a major focus in the hearing research field since the 1980s when direct mechanical gating of a transduction channel was proposed (Corey and Hudspeth J Neurosci 3:962-976, 1983). To this day, the molecular identity of this channel remains controversial. However, many of the hcMET channel's properties have been characterized, including pore properties, calcium-dependent ion permeability, rectification, and single channel conductance. At this point, elucidating the molecular identity of the hcMET channel will provide new tools for understanding the mechanotransduction process. This review discusses the significance of identifying the hcMET channel, the difficulties associated with that task, as well as the establishment of clear criteria for this identification. Finally, we discuss potential candidate channels in light of these criteria.

    View details for DOI 10.1007/s00424-014-1606-z

    View details for Web of Science ID 000347157200007

    View details for PubMedID 25241775

  • Adaptation of Mammalian Auditory Hair Cell Mechanotransduction Is Independent of Calcium Entry NEURON Peng, A. W., Effertz, T., Ricci, A. J. 2013; 80 (4): 960-972


    Adaptation is a hallmark of hair cell mechanotransduction, extending the sensory hair bundle dynamic range while providing mechanical filtering of incoming sound. In hair cells responsive to low frequencies, two distinct adaptation mechanisms exist, a fast component of debatable origin and a slow myosin-based component. It is generally believed that Ca(2+) entry through mechano-electric transducer channels is required for both forms of adaptation. This study investigates the calcium dependence of adaptation in the mammalian auditory system. Recordings from rat cochlear hair cells demonstrate that altering Ca(2+) entry or internal Ca(2+) buffering has little effect on either adaptation kinetics or steady-state adaptation responses. Two additional findings include a voltage-dependent process and an extracellular Ca(2+) binding site, both modulating the resting open probability independent of adaptation. These data suggest that slow motor adaptation is negligible in mammalian auditory cells and that the remaining adaptation process is independent of calcium entry.

    View details for DOI 10.1016/j.neuron.2013.08.025

    View details for Web of Science ID 000327281200013

  • Direct gating and mechanical integrity of Drosophila auditory transducers require TRPN1. Nature neuroscience Effertz, T., Nadrowski, B., Piepenbrock, D., Albert, J. T., Göpfert, M. C. 2012; 15 (9): 1198-1200


    The elusive transduction channels for hearing are directly gated mechanically by the pull of gating springs. We found that the transient receptor potential (TRP) channel TRPN1 (NOMPC) is essential for this direct gating of Drosophila auditory transduction channels and that the channel-spring complex was disrupted if TRPN1 was lost. Our results identify TRPN1 as a mechanical constituent of the fly's auditory transduction complex that may act as the channel and/or gating spring.

    View details for DOI 10.1038/nn.3175

    View details for PubMedID 22842145

  • NompC TRP Channel Is Essential for Drosophila Sound Receptor Function CURRENT BIOLOGY Effertz, T., Wiek, R., Goepfert, M. C. 2011; 21 (7): 592-597


    The idea that the NompC TRPN1 channel is the Drosophila transducer for hearing has been challenged by remnant sound-evoked nerve potentials in nompC nulls. We now report that NompC is essential for the function of Drosophila sound receptors and that the remnant nerve potentials of nompC mutants are contributed by gravity/wind receptor cells. Ablating the sound receptors reduces the amplitude and sensitivity of sound-evoked nerve responses, and the same effects ensued from mutations in nompC. Ablating the sound receptors also suffices to abolish mechanical amplification, which arises from active receptor motility, is linked to transduction, and also requires NompC. Calcium imaging shows that the remnant nerve potentials in nompC mutants are associated with the activity of gravity/wind receptors and that the sound receptors of the mutants fail to respond to sound. Hence, Drosophila sound receptors require NompC for mechanical signal detection and amplification, demonstrating the importance of this transient receptor potential channel for hearing and reviving the idea that the fly's auditory transducer might be NompC.

    View details for DOI 10.1016/j.cub.2011.02.048

    View details for Web of Science ID 000289662600023

    View details for PubMedID 21458266

  • Antennal hearing in insects--new findings, new questions. Hearing research Nadrowski, B., Effertz, T., Senthilan, P. R., Göpfert, M. C. 2011; 273 (1-2): 7-13


    Mosquitoes, certain Drosophila species, and honey bees use Johnston's organ in their antennae to detect the wing-beat sounds of conspecifics. Recent studies on these insects have provided novel insights into the intricacies of insect hearing and sound communication, with main discoveries including transduction and amplification mechanisms as known from vertebrate hearing, functional and molecular diversifications of mechanosensory cells, and complex mating duets that challenge the frequency-limits of insect antennal ears. This review discusses these recent advances and outlines potential avenues for future research.

    View details for DOI 10.1016/j.heares.2010.03.092

    View details for PubMedID 20430076

  • Transcuticular optical imaging of stimulus-evoked neural activities in the Drosophila peripheral nervous system NATURE PROTOCOLS Kamikouchi, A., Wiek, R., Effertz, T., Goepfert, M. C., Fiala, A. 2010; 5 (7): 1229-1235


    The nervous system of Drosophila is widely used to study neuronal signal processing because the activities of neurons can be controlled and monitored by cell type-specific expression of genetically encoded actuator and sensor proteins. Measuring neural activities in adult flies, however, usually requires surgical approaches to penetrate the firm and pigmented cuticular exoskeleton. Interfering with this exoskeleton is critical in the case of the peripheral nervous system (PNS), as sensory neurons are often located directly beneath the cuticle and are associated with specialized stimulus-receiving and -conducting cuticular structures. In this article, we describe how the activities of these neurons can be probed nondestructively through the cuticle if a genetically encoded fluorescent protein sensor with strong baseline fluorescence is used. The method is exemplified for mechanosensory neurons in the adult antenna but can also be applied to many other PNS neurons, as is shown for the femoral chordotonal organ located in the fly's leg.

    View details for DOI 10.1038/nprot.2010.85

    View details for Web of Science ID 000279404800001

    View details for PubMedID 20595952

  • Using Drosophila for studying fundamental processes in hearing Lu, Q., Senthilan, P. R., Effertz, T., Nadrowski, B., Goepfert, M. C. OXFORD UNIV PRESS INC. 2009: 674-680


    Apart from detecting sounds, vertebrate ears occasionally produce sounds. These spontaneous otoacoustic emissions are the most compelling evidence for the existence of the cochlear amplifier, an active force-generating process within the cochlea that resides in the motility of the hair cells. Insects have neither a cochlea nor hair cells, yet recent studies demonstrate that an active process that is equivalent to the cochlear amplifier occurs in at least some insect ears; like hair cells, the chordotonal sensory neurons that mediate hearing in Drosophila actively generate forces that augment the minute vibrations they transduce. This neuron-based force-generation, its impact on the ear's macroscopic performance, and the underlying molecular mechanism are the topics of this article, which summarizes some of the recent findings on how the Drosophila organ of hearing works. Functional parallels with vertebrate auditory systems are described that recommend the fly for the study of fundamental processes in hearing.

    View details for DOI 10.1093/icb/icp072

    View details for Web of Science ID 000272083100006

    View details for PubMedID 21665849

  • The neural basis of Drosophila gravity-sensing and hearing NATURE Kamikouchi, A., Inagaki, H. K., Effertz, T., Hendrich, O., Fiala, A., Goepfert, M. C., Ito, K. 2009; 458 (7235): 165-U1


    The neural substrates that the fruitfly Drosophila uses to sense smell, taste and light share marked structural and functional similarities with ours, providing attractive models to dissect sensory stimulus processing. Here we focus on two of the remaining and less understood prime sensory modalities: graviception and hearing. We show that the fly has implemented both sensory modalities into a single system, Johnston's organ, which houses specialized clusters of mechanosensory neurons, each of which monitors specific movements of the antenna. Gravity- and sound-sensitive neurons differ in their response characteristics, and only the latter express the candidate mechanotransducer channel NompC. The two neural subsets also differ in their central projections, feeding into neural pathways that are reminiscent of the vestibular and auditory pathways in our brain. By establishing the Drosophila counterparts of these sensory systems, our findings provide the basis for a systematic functional and molecular dissection of how different mechanosensory stimuli are detected and processed.

    View details for DOI 10.1038/nature07810

    View details for Web of Science ID 000264059700035

    View details for PubMedID 19279630