Simple Ways to Measure Behavioral Responses of Drosophila to Stimuli and Use of These Methods to Characterize a Novel Mutant

The behavioral responses of adult Drosophila fruit flies to a variety of sensory stimuli – light, volatile and non-volatile chemicals, temperature, humidity, gravity, and sound - have been measured by others previously. Some of those assays are rather complex; a review of them is presented in the Discussion. Our objective here has been to find out how to measure the behavior of adult Drosophila fruit flies by methods that are inexpensive and easy to carry out. These new assays have now been used here to characterize a novel mutant that fails to be attracted or repelled by a variety of sensory stimuli even though it is motile

Ionic liquids at electrified interfaces

Until recently, “room-temperature” (<100–150 °C) liquid-state electrochemistry was mostly electrochemistry of diluted electrolytes(1)–(4) where dissolved salt ions were surrounded by a considerable amount of solvent molecules. Highly concentrated liquid electrolytes were mostly considered in the narrow (albeit important) niche of high-temperature electrochemistry of molten inorganic salts(5-9) and in the even narrower niche of “first-generation” room temperature ionic liquids, RTILs (such as chloro-aluminates and alkylammonium nitrates).(10-14) The situation has changed dramatically in the 2000s after the discovery of new moisture- and temperature-stable RTILs.(15, 16) These days, the “later generation” RTILs attracted wide attention within the electrochemical community.(17-31) Indeed, RTILs, as a class of compounds, possess a unique combination of properties (high charge density, electrochemical stability, low/negligible volatility, tunable polarity, etc.) that make them very attractive substances from fundamental and application points of view.(32-38) Most importantly, they can mix with each other in “cocktails” of one’s choice to acquire the desired properties (e.g., wider temperature range of the liquid phase(39, 40)) and can serve as almost “universal” solvents.(37, 41, 42) It is worth noting here one of the advantages of RTILs as compared to their high-temperature molten salt (HTMS)(43) “sister-systems”.(44) In RTILs the dissolved molecules are not imbedded in a harsh high temperature environment which could be destructive for many classes of fragile (organic) molecules

How to measure response to a non-volatile repellent, quinine HCl.

<p>The red tube indicates agar plus quinine, the blue tube agar without quinine. Flies start out at the right end and go away from the quinine. Readings are in each of the halves. See text.</p

Repulsion of flies by gravity.

<p>Data are presented for the top third of the tube. Mean ± S.E.M. for 6 vertical experiments and 6 horizontal experiments.</p

Repulsion of flies by cold.

<p>A) Flies are placed opposite a cold source. Data from each of the quarters are presented for every 5 minutes. Mean ± S.E.M. for 8 experiments. B) Control without cold. Mean ± S.E.M. for 2 experiments. Temperatures in each quarter are the average of 8 experiments for A and 2 experiments for B.</p

How to measure response to water.

<p>Flies start out at the left end and go to the water-Kimwipe end. Readings are in 4 parts as indicated. See text.</p

How to measure response to light.

<p>Flies start out in the vial and go to the light source. Readings are in 4 parts as indicated. See text.</p

A mutant that fails to respond to multiple stimuli.

<p>At the right end of an 11 cm×70 cm tube were placed two repellents—benzaldehyde and high temperature (38°C)—and at the left end two attractants—light and a favored temperature (29°C). Flies were placed near the repellent end (labeled here “origin”). A) Nearly all the parental flies went to the attractant end (labeled here “furthest”). Mean ± S.E.M. for 7 experiments. B) Mutant flies failed to be repelled or attracted. Mean ± S.E.M. for 4 experiments. Details will be presented elsewhere [Vang <i>et al.</i>, “<i>Drosophila</i> mutants that are motile but fail to respond to stimuli” (manuscript in preparation, 2012)].</p