@article{PanzerZhangKonteetal.2021,
  author    = {Panzer, Sabine and Zhang, Chong and Konte, Tilen and Br{\"a}uer, Celine and Diemar, Anne and Yogendran, Parathy and Yu-Strzelczyk, Jing and Nagel, Georg and Gao, Shiqiang and Terpitz, Ulrich},
  title     = {Modified Rhodopsins From Aureobasidium pullulans Excel With Very High Proton-Transport Rates},
  series = {Frontiers in Molecular Biosciences},
  volume    = {8},
  journal   = {Frontiers in Molecular Biosciences},
  issn      = {2296-889X},
  doi       = {10.3389/fmolb.2021.750528},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-249248},
  year      = {2021},
  abstract  = {Aureobasidium pullulans is a black fungus that can adapt to various stressful conditions like hypersaline, acidic, and alkaline environments. The genome of A. pullulans exhibits three genes coding for putative opsins ApOps1, ApOps2, and ApOps3. We heterologously expressed these genes in mammalian cells and Xenopus oocytes. Localization in the plasma membrane was greatly improved by introducing additional membrane trafficking signals at the N-terminus and the C-terminus. In patch-clamp and two-electrode-voltage clamp experiments, all three proteins showed proton pump activity with maximal activity in green light. Among them, ApOps2 exhibited the most pronounced proton pump activity with current amplitudes occasionally extending 10 pA/pF at 0 mV. Proton pump activity was further supported in the presence of extracellular weak organic acids. Furthermore, we used site-directed mutagenesis to reshape protein functions and thereby implemented light-gated proton channels. We discuss the difference to other well-known proton pumps and the potential of these rhodopsins for optogenetic applications.},
  language  = {en}
}
@article{LichtensteinGruebelSpaethe2018,
  author    = {Lichtenstein, Leonie and Gr{\"u}bel, Kornelia and Spaethe, Johannes},
  title     = {Opsin expression patterns coincide with photoreceptor development during pupal development in the honey bee, Apis mellifera},
  series = {BMC Developmental Biology},
  volume    = {18},
  journal   = {BMC Developmental Biology},
  number    = {1},
  doi       = {10.1186/s12861-018-0162-8},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175665},
  year      = {2018},
  abstract  = {Background: The compound eyes of insects allow them to catch photons and convert the energy into electric signals. All compound eyes consist of numerous ommatidia, each comprising a fixed number of photoreceptors. Different ommatidial types are characterized by a specific set of photoreceptors differing in spectral sensitivity. In honey bees, males and females possess different ommatidial types forming distinct retinal mosaics. However, data are lacking on retinal ontogeny and the mechanisms by which the eyes are patterned. In this study, we investigated the intrinsic temporal and circadian expression patterns of the opsins that give rise to the ultraviolet, blue and green sensitive photoreceptors, as well as the morphological maturation of the retina during pupal development of honey bees. Results: qPCR and histological labeling revealed that temporal opsin mRNA expression differs between sexes and correlates with rhabdom elongation during photoreceptor development. In the first half of the pupal stage, when the rhabdoms of the photoreceptors are still short, worker and (dorsal) drone retinae exhibit similar expression patterns with relatively high levels of UV (UVop) and only marginal levels of blue (BLop) and green (Lop1) opsin mRNA. In the second half of pupation, when photoreceptors and rhabdoms elongate, opsin expression in workers becomes dominated by Lop1 mRNA. In contrast, the dorsal drone eye shows high expression levels of UVop and BLop mRNA, whereas Lop1 mRNA level decreases. Interestingly, opsin expression levels increase up to 22-fold during early adult life. We also found evidence that opsin expression in adult bees is under the control of the endogenous clock. Conclusions: Our data indicate that the formation of the sex-specific retinal composition of photoreceptors takes place during the second half of the pupal development, and that opsin mRNA expression levels continue to increase in young bees, which stands in contrast to Drosophila, where the highest expression levels are found during the late pupal stage and remain constant in adults. From an evolutionary perspective, we hypothesize that the delayed retinal maturation during the early adult phase is linked to the delayed transition from indoor to outdoor activities in bees, when vision becomes important.},
  language  = {en}
}