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Varela, E.

Publications and source records attributed to Varela, E..

2 recordsLinked to original sources

Aquavert: Imaging and Microfluidics for Vertical Swimming of Microorganisms

Investigating aquatic microorganisms swimming and feeding behaviors under well-controlled conditions is of great interest across multiple disciplines. Thus, broader access to resources that enable these investigations is desirable. Given the organisms microscopic dimensions, an ideal system should combine microscopy to visualize and fluidics to control and modulate their environments. We report an integrated device (Aquavert) that combines DIY microscopy and microfluidics for biomechanical investigations of marine microorganisms, emphasizing vertical swimming. The DIY microscope was developed for modularity, and imaging chambers were secured in vertical orientations (either in portrait or landscape mode). Fluid channels were used to introduce flow and fluid segmentation while remaining upright. Fluid segmentation established two distinct environments (e.g., with and without algae) in neighboring regions inside a chamber. System application with multiple marine larvae (sand dollars, sea urchins, and starfish) and introduction of unicellular algae were demonstrated. Finally, the devices capabilities were extended to fluorescence imaging to visualize tracer beads. The role of gravity is often ignored in conventional plate or microfluidic experiments. Beyond the current application, Aquavert enables investigations of the behavior and physiology of microorganisms where the role of gravity is critical.

biophysics↗

Discrete escape responses are generated by neuropeptide-mediated circuit logic

Animals display a plethora of escape behaviors when faced with environmental threats. Selection of the appropriate response by the underlying neuronal network is key to maximize chances of survival. We uncovered a somatosensory network in Drosophila larvae that encodes two escape behaviors through input-specific neuropeptide action. Sensory neurons required for avoidance of noxious light and escape in response to harsh touch, each converge on discrete domains of the same neuromodulatory hub neurons. These gate harsh touch responses via short Neuropeptide F, but noxious light avoidance via compartmentalized, acute Insulin-like peptide 7 action and cognate Relaxin-family receptor signaling in connected downstream neurons. Peptidergic hub neurons can thus act as central circuit elements for first order processing of converging sensory inputs to gate specific escape responses. One Sentence SummaryCompartment-specific neuropeptide action regulates sensory information processing to elicit discrete escape behavior in Drosophila larvae.

neuroscience↗