Systematic morphological and morphometric analysis of identified olfactory receptor neurons inDrosophila melanogaster

Abstract

The biophysical properties of sensory neurons are influenced by their morphometric and morphological features, whose precise measurements require high-quality volume electron microscopy (EM). However, systematic surveys of these nanoscale characteristics for identified neurons are scarce. Here, we characterize the morphology of Drosophila olfactory receptor neurons (ORNs) across the majority of genetically identified sensory hairs. By analyzing serial block-face electron microscopy (SBEM) images of cryofixed antennal tissues, we compile an extensive morphometric dataset based on 122 reconstructed 3D models of 33 identified ORN types. In addition, we observe multiple novel features, including extracellular vacuoles within sensillum lumen, intricate dendritic branching, mitochondria enrichment in select ORNs, novel sensillum types, and empty sensilla containing no neurons, which raise new questions pertinent to cell biology and sensory neurobiology. Our systematic survey is critical for future investigations into how the size and shape of sensory neurons influence their responses, sensitivity and circuit function.

Unilateral ephaptic program underlying sweetness dominance

“…3F, left). In other words, sGRN soma volume was like that of the large ORNs 12,46 . We did not see any correlation between the measured volume difference and the voxel intensities (Fig.…”

Functional olfactory evolution in Drosophila suzukii and the subgenus Sophophora

“…With all this in mind, whatever the cause for this change in the ab2B and ab3A OSNs, we show it occurs repeatedly, and that it is therefore likely to provide a new avenue for rapid olfactory evolution throughout the Sophophora subgenus ( Figure 4 ). Recent research into D. melanogaster has also highlighted an additional large basiconic, currently named abx(3), that is indistinguishable from ab3 based on morphological and morphometric features, though its receptor identity and function have yet to be characterized ( Gonzales et al., 2021 ).…”