volatile-sex-pheromone-extraction-chemoattraction-assay

Volatile Sex Pheromone Extraction and Chemoattraction Assay in <i>Caenorhabditis elegans</i>

Chemical communication is vital in organismal health, reproduction, and overall well-being. Understanding the molecular pathways, neural processes, and ...

California Institute of Technology

Neuropeptides are evolutionarily conserved modulators of many aspects of animal behavior and physiology, and expand the repertoire of processes that can be controlled by a limited number of neurons. Deciphering the neuropeptidergic codes that govern distinct processes requires systematic functional analyses of neuropeptides and their cognate receptors. Even in well-studied model organisms like Caenorhabditis elegans, however, such efforts have been precluded by a lack of mutant reagents. Here, we generated and screened 21 C. elegans neuropeptide G-protein coupled receptor mutants with no pre-existing reagents for the touch-evoked escape response, and implicated six receptors expressed in diverse neuron classes representing multiple circuit levels in this behavior. We further characterized the mutant with the most severe phenotype, frpr-14, which was defective in multiple behavioral paradigms. We leveraged this range of phenotypes to reveal that FRPR-14 modulation of different precommand interneuron classes, AVH and AIB, can drive distinct behavioral subsets, demonstrating cellular context-dependent roles for FRPR-14 signaling. We then show that Caenorhabditis briggsae CBR-FRPR-14 modulates an AVH-like interneuron pair to regulate the same behaviors as C. elegans but to a smaller extent. Our results also suggest that differences in touch-evoked escape circuit architecture between closely related species results from changes in neuropeptide receptor expression pattern, as opposed to ligand-receptor pairing. This study provides insights into the principles utilized by a compact, multiplexed nervous system to generate intraspecific behavioral complexity and interspecific variation.

A conserved behavioral role for a nematode interneuron neuropeptide receptor.

Animals integrate sensory information from the environment and display various behaviors in response to external stimuli. In  hermaphrodites, 33 types of sensory neurons are responsible for chemosensation, olfaction, and mechanosensation. However, the functional roles of all sensory neurons have not been systematically studied due to the lack of facile genetic accessibility. A bipartite cGAL-UAS system has been previously developed to study tissue- or cell-specific functions in . Here, we report a toolkit of new cGAL drivers that can facilitate the analysis of a vast majority of the 60 sensory neurons in  hermaphrodites. We generated 37 sensory neuronal cGAL drivers that drive cGAL expression by cell-specific regulatory sequences or intersection of two distinct regulatory regions with overlapping expression (split cGAL). Most cGAL-drivers exhibit expression in single types of cells. We also constructed 28 UAS effectors that allow expression of proteins to perturb or interrogate sensory neurons of choice. This cGAL-UAS sensory neuron toolkit provides a genetic platform to systematically study the functions of  sensory neurons.

A cGAL-UAS bipartite expression toolkit for  sensory neurons.

Bacteria can swim upstream in a narrow tube and pose a clinical threat of urinary tract infection to patients implanted with catheters. Coatings and structured surfaces have been proposed to repel bacteria, but no such approach thoroughly addresses the contamination problem in catheters. Here, on the basis of the physical mechanism of upstream swimming, we propose a novel geometric design, optimized by an artificial intelligence model. Using , we demonstrate the anti-infection mechanism in microfluidic experiments and evaluate the effectiveness of the design in three-dimensionally printed prototype catheters under clinical flow rates. Our catheter design shows that one to two orders of magnitude improved suppression of bacterial contamination at the upstream end, potentially prolonging the in-dwelling time for catheter use and reducing the overall risk of catheter-associated urinary tract infection.

Xuan Wan

Division of Biology and Biological Engineering

California Institute of Technology

Volatile Sex Pheromone Extraction and Chemoattraction Assay in Caenorhabditis elegans

Xuan Wan

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Division of Biology and Biological Engineering

California Institute of Technology

Volatile Sex Pheromone Extraction and Chemoattraction Assay in Caenorhabditis elegans

Division of Biology and Biological Engineering