Evidence for Human-Centric In-Vehicle Lighting: Part 1

Today, up to hundreds of RGB and W-LEDs are positioned in a vehicle’s interior context and are able to be individually controlled in intensity, color and sequence. However, which kind of illumination distracts or supports car occupants and how to define such a modern illumination system is still under discussion and unknown. For that, first a definition for an in-vehicle lighting system is introduced. Second, a globally distributed study was performed based on a free-access online survey to investigate in-vehicle lighting for visual signaling within 10 colors, eight positions and six dynamic patterns. In total, 238 participants from China and Europe rated color preferences, color moods, light-position preferences, differences between manual and autonomous driving and also different meanings for dynamic lighting patterns. Out of these, three strong significant (p < 0.05) color preference groups were identified with a polarized, accepted or merged character. For the important driving-signaling mood attention, we found a significant hue dependency for Europeans which was missing within the Chinese participants. In addition, we identified that light positioned at the door and foot area was globally favored. Furthermore, we evaluated qualitative results: men are primarily focusing on fast-forward, whereas women paid more attention on practical light usage. These findings conclude the need for a higher lighting-car-occupant adaptation in the future grounded by deeper in-vehicle human factors research to achieve a higher satisfaction level. In interdisciplinary terms, our findings might also be helpful for interior building or general modern cockpit designs for trains or airplanes.

Transmembrane Signaling Regulates the Remodeling of the Actin Cytoskeleton:Roles of PKC and Adducin

Members of the conventional protein kinase C (cPKC) family are activated by both DAG and Ca2+ and have been implicated in the regulation of the actin cytoskeleton. Drosophila contains two cPKCs, Pkc53E (Pkc1) and eye-PKC (Pkc2); mutants missing each PKC lead to retinal degeneration. While eye-PKC is critical for the visual signaling, the role of Pkc53E is not known. We identified a photoreceptor-specific isoform of Pkc53E and show Pkc53E-RNAi negatively impacts the actin cytoskeleton of rhabdomeres. Interestingly, Pkc53E-RNAi enhances the degeneration of norpAP24 photoreceptors, suggesting Pkc53E could be activated independently of NorpA/PLCβ4. We further demonstrate that in norpAP24 photoreceptors Plc21C can be activated by Gq, which is responsible for the activation of Pkc53E. We explored whether Pkc53E regulates adducin in Drosophila photoreceptors. Adducin cross-links the actin cytoskeleton to the spectrin network, which is blunted by PKC phosphorylation. Importantly, we observed that phosphorylation of adducin was greatly reduced in a null allele of pkc53E. Downregulation of hts that encodes Drosophila adducin, exerts a more severe effect than Pkc53E-RNAi to impact the actin cytoskeleton. In contrast, overexpression of a mCherry tagged Add2, one of the three Drosophila adducin isoforms, led to the apical expansion of rhabdomeres with overgrowth of the actin cytoskeleton. This phenotype is likely caused by the dominant-negative activity of the tagged Add2 as it also was observed in α-spectrin-RNAi or β-spectrin-RNAi. Interestingly, downregulation of Pkc53E does not suppress the expansion of rhabdomeres during development, but negatively affects the appearance of rhabdomeres in adult photoreceptors. We conclude that Drosophila adducin has two distinct functions: in pupal photoreceptors, it regulates rhabdomere morphogenesis, which is independent of Pkc53E. In adult photoreceptors, it promotes the maintenance of the actin cytoskeleton, which is regulated by Pkc53E in response to the light-induced activation of the PLCβ activity.

Calcium Channels in Retinal Function and Disease

Voltage-gated Ca2+ (Cav) channels play pivotal roles in regulating gene transcription, neuronal excitability, and neurotransmitter release. In order to meet the spatial and temporal demands of visual signaling, Cav channels exhibit unusual properties in the retina compared to their counterparts in other areas of the nervous system. Here, we review current concepts regarding the specific subtypes of Cav channels expressed in the retina, their intrinsic properties and forms of modulation, and how their dysregulation could lead to retinal disease.

Function analysis of the calls of Dendropsophus microps of the Campos do Jordão State Park, São Paulo, Brazil

In this study, we describe the calls emitted by Dendropsophus microps, a species of frog in the family Hylidae, in Serra da Mantiqueira, Campos do Jordão, São Paulo, Brazil, and evaluate their functions in the social context using playback experiments. Between October 2016 and November 2017, 15 males of D. microps were recorded. Six hundred and five calls were analyzed and the existence of five types of call compositions was verified: simple call “A normal”; compound call “Af”; shorter “A” call + longer “A” call; “A + Af” calls; and simple call “B”; demonstrating the presence of compound calling in the vocalization structure. One thousand, six hundred and seventeen calls were recorded during the playback experiment in response to the 5 previously constructed stimuli. The “B” call was the most emitted in response to stimuli. The “A”, “Af”, “AA” and “AAf” stimuli caused visual signaling. We recorded a series of 4 to 5 “A” calls during agonistic interactions. Call "B" was identified as an advertisement call and calls "A", "Af", "AA" and "AAf" as aggressive calls. The presence of visual communication in addition to the acoustic communication of these individuals was also observed. The findings increase knowledge of the calling repertoire of this species and can be used in the future in other behavioral and taxonomic studies.

Structure of the Visual Signaling Complex between Transducin and Phosphodiesterase 6

SUMMARYHeterotrimeric G proteins communicate signals from activated G protein-coupled receptors to downstream effector proteins. In the phototransduction pathway responsible for vertebrate vision, the G protein-effector complex is comprised of the GTP-bound transducin α subunit (GαT·GTP) and the cyclic GMP (cGMP) phosphodiesterase 6 (PDE6), which stimulates cGMP hydrolysis to transmit signals to the optic nerve. Here we report a cryo-electron microscopy (cryoEM) structure of PDE6 complexed to GTP-bound GαT. The structure reveals two GαT·GTP subunits engaging the PDE6 hetero-tetramer at both the PDE6 catalytic core and the PDEγ subunits, driving extensive rearrangements to relieve all inhibitory constraints on enzyme catalysis. Analysis of the conformational ensemble in the cryoEM data highlights the dynamic nature of the contacts between the two GαT·GTP subunits and PDE6 that support an alternating-site catalytic mechanism.

Comparative Transcriptomics Provides Insights into Reticulate and Adaptive Evolution of a Butterfly Radiation

Butterfly eyes are complex organs that are composed of a diversity of proteins and they play a central role in visual signaling and ultimately, speciation, and adaptation. Here, we utilized the whole eye transcriptome to obtain a more holistic view of the evolution of the butterfly eye while accounting for speciation events that co-occur with ancient hybridization. We sequenced and assembled transcriptomes from adult female eyes of eight species representing all major clades of the Heliconius genus and an additional outgroup species, Dryas iulia. We identified 4,042 orthologous genes shared across all transcriptome data sets and constructed a transcriptome-wide phylogeny, which revealed topological discordance with the mitochondrial phylogenetic tree in the Heliconius pupal mating clade. We then estimated introgression among lineages using additional genome data and found evidence for ancient hybridization leading to the common ancestor of Heliconius hortense and Heliconius clysonymus. We estimated the Ka/Ks ratio for each orthologous cluster and performed further tests to demonstrate genes showing evidence of adaptive protein evolution. Furthermore, we characterized patterns of expression for a subset of these positively selected orthologs using qRT-PCR. Taken together, we identified candidate eye genes that show signatures of adaptive molecular evolution and provide evidence of their expression divergence between species, tissues, and sexes. Our results demonstrate: 1) greater evolutionary changes in younger Heliconius lineages, that is, more positively selected genes in the cydno–melpomene–hecale group as opposed to the sara–hortense–erato group, and 2) suggest an ancient hybridization leading to speciation among Heliconius pupal-mating species.