Ac dc headstage preamplifier

The electrophysiological recordings of whole male and female antennae in response to four sex pheromone components and pheromone analogs were performed according to the standard technique (Cao et al., 2016 (link)). The components used in the EAG assay were dissolved in paraffin oil and diluted to 10 μg/μL. A piece of filter paper (0.5 × 5 cm) loaded with 10 μL pheromones was used as a stimulus, and paraffin oil was used as a control. 3-day-old moths were tested and signals from antennae were amplified with a 10 × AC/DC headstage preamplifier (Syntech, Kirchzarten, Germany) and further acquired with an Intelligent Data Acquisition Controller (IDAC-4-USB; Syntech, Kirchzarten, Germany). Signals were recorded with Syntech EAG-software (EAGPro 2.0). After subtracting the responses of the control, data were analyzed using the Student’s t-test (El-Sayed et al., 2009 (link)).

The antennae of 2- to 3-day-old virgin male and female moths were cut at the base of the flagellum. After removing the tip, one antenna was inserted between two glass electrodes filled with 0.1 M KCl solution. In each test, a 10-μl solution of each odorant was added onto a piece of filter paper (0.5 cm × 0.5 cm) and then inserted into a Pasteur pipette. About 100 ng/μl stock solutions of individual odorants and different doses of the mixture IAC were prepared with paraffin oil. A continuous airflow of 30 ml/s was produced by a stimulus controller (CS-55, Syntech, Kirchzarten, Germany). Odor stimulation was controlled by a puff of purified air (0.2 s at 10 ml/s airflow) from the CS-55. EAG signals were amplified with a 10× AC/DC headstage preamplifier (Syntech) and further acquired with an Intelligent Data Acquisition Controller (IDAC-4-USB, Syntech) (Cao et al. 2016 (link)). The signals were recorded, monitored, and analyzed using Syntech EAG-software (Syntech, Germany). The EAG response values for each compound were calculated by subtracting the value of the same antennae corresponding to a solvent blank of paraffin oil.