Biology subjects

Neupert, S.

Publications and source records attributed to Neupert, S..

4 recordsLinked to original sources

bioRxiv2024

Pigment-dispersing factor neuropeptides act as multifunctional hormones and modulators in tardigrades

Pigment-dispersing factors (PDFs) are neuropeptides that play key roles in controlling the circadian rhythms in various insects, whereas their function remains elusive in other protostomes including tardigrades (water bears). Here we show that the three PDFs of the tardigrade Hypsibius exemplaris are co-localized in two pairs of inner lobe cells in the brain, whereas only one PDF occurs in four additional cerebral and two extracerebral cells. The axons of the inner lobe cells pass through the contralateral brain hemisphere, descend to the ventral nerve cord and terminate in two pairs of potential release sites in the posteriormost trunk ganglion. Using in vitro assays, we demonstrate that all three PDFs and their deorphanized receptor (PDFR) are functional. Widespread localization of PDFR suggests that tardigrade PDFs may act as multifunctional hormones and neuromodulators that control major functions including light detection, neural processing, locomotion, feeding, digestion, osmoregulation, growth, embryonic development, and oogenesis/reproduction.

zoology↗

bioRxiv2024

Functional characterization of CCHamides and deorphanization of their receptors in the yellow fever mosquito, Aedes aegypti

As a widely distributed anthropophilic mosquito species and vector of various arboviruses, Aedes aegypti poses a significant threat to human health on a global scale. Investigating mosquito neuropeptides allows us to better understand their physiology. The neuropeptides CCHamide1 (CCHa-1) and CCHamide-2 (CCHa-2) and their associated G protein-coupled receptors (CCHa-1R and CCHa-2R) were recently identified and studied across insects. However, expression profiles and physiological roles of CCHamides and their receptors in many other insects, including A. aegypti, remain unclear. This research aimed to quantify and localize the expression of CCHamides along with their receptors and to elucidate their physiological function in the yellow fever mosquito. RT-qPCR analysis revealed transcript abundance of CCHamides and receptors changes over development. Differential expression was also observed in tissues/organs of adult mosquitoes indicating CCHa-1 and CCHa-2 transcripts are most highly enriched in the midgut, while receptors are expressed across various tissues. Further, CCHamides were immunolocalized in neurons in the brain and ventral nerve cord along with enteroendocrine cells in the posterior midgut adjacent to the midgut-hindgut junction, corroborating their transcript expression profiles. Using different mass spectrometrical approaches, presence of CCHamides were confirmed in the brain of both sexes, including the pars intercerebralis of female mosquitoes, as well as in the gut of adult mosquitoes. For chemical identification of predicted CCHamides, we analyzed brain and gut extracts by ESI-Q Exactive Orbitrap MS and resulting fragmentations confirmed CCHa1 and CCHa2 in brain and midgut samples of both male and female mosquitoes. A heterologous functional assay was used to confirm the specificity and sensitivity of the two CCHamide receptors by assessing their activation in response to diverse mosquito peptides, which confirmed CCHa-1 and CCHa-2 as the natural ligands. Finally, using a capillary feeder (CAFE) bioassay, our results suggest that CCHa-2 modulates feeding behaviour in female mosquitoes.

zoology↗

bioRxiv2022

Sugar alcohols have the potential as bee-safe feeding stimulants for wasp control

Pest insects are often baited with poisoned feeding stimulants, the most common of which are sugars. However, sugars are attractive for most animal species, which makes it difficult to target only a specific pest insect species. Here, we assessed different sugar alcohols for their potential as more species-selective feeding stimulants for pest insects. We tested the attractiveness of the sugar alcohols sorbitol, xylitol and erythritol with a capillary feeder assay in wasps (as potential pest insects, because introduced wasps are a pest in many regions) and bees (as non-target insects). For the common wasp (Vespula vulgaris), sorbitol and xylitol acted as nutritive feeding stimulants, and erythritol acted as a non-nutritive feeding stimulant. For the buff-tailed bumble bee (Bombus terrestris), sorbitol acted as a feeding stimulant, while for the honey bee (Apis mellifera), none of the sugar alcohols acted as feeding stimulant. The species-specific preferences for sugar alcohols suggest their potential as species-selective insect baits. The wasp-specific preference for xylitol suggests its potential as bee-safe alternative to sugar-containing bait for wasp pest control. GRAPHICAL ABSTRACT O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY We tested the attractiveness of sugar alcohols with a capillary feeder assay in wasps and bees. Species-specific preferences suggests that sugar alcohols have the potential for being used as bee-safe insect baits. C_FIG_DISPLAY

ecology↗

bioRxiv2020

Adaptive evolution of olfactory degeneration in recently flightless insects

Fast-moving animals need fast-acting sensory systems. Flying insects have thus evolved exceptionally quick visual (1) and olfactory processing ability (2). For example, flighted insects can track the temporal structure of turbulent odor plumes at rates above 100 Hz (3). The evolutionary lability of such sensory systems, however, remains unknown. We test for rapid evolutionary shifts in olfactory processing speed associated with flight loss, through neurobiological comparisons of sympatric flighted versus flightless lineages within a wing-polymorphic stonefly species. Our analyses of sensory responses reveal that recently-evolved flightless lineages have substantially degraded olfactory acuity. By comparing flighted versus flightless ecotypes with similar genetic backgrounds (4), we eliminate other confounding factors that might have affected the evolution of their olfactory reception mechanisms. Our detection of different patterns of degraded olfactory sensitivity and speed in independently wing-reduced lineages highlights parallel evolution of sensory degeneration. These reductions in sensory ability also echo the rapid vestigialization of wings themselves (4, 5), and represent a neurobiological parallel to the convergent phenotypic shifts seen under sharp selective gradients in other systems (e.g. parallel loss of vision in diverse cave fauna (6)). Our study provides the first direct evidence for the hypothesis that flight poses a selective pressure on the speed of olfactory receptor neurons. Our findings also emphasize the energetic costs of rapid olfaction, and the key role of natural selection in shaping dramatic neurobiological shifts. Significance StatementFlying insects move fast and have therefore evolved exceptionally quick-acting sensory systems. The speed with which such neurobiological shifts can evolve, however, remains unclear. Under the use it or lose it hypothesis, loss of flight should lead to degradation of this fast sensory processing ability. We test for evolutionary reductions in olfactory acuity linked to flight loss, through neurobiological comparisons of flightless versus flighted lineages within a wing-polymorphic insect. Our analyses reveal that newly wing-reduced populations have substantially degraded olfactory acuity, with parallel reductions in this sensory ability detected in independently flightless lineages. These findings reveal that flight poses strong selective pressure for rapid olfaction, and highlight the potential of natural selection in rapidly shaping adaptive shifts in animal sensory systems.

neuroscience↗