Insect antenna potential measurement system (EAG)
——Insects use sex pheromones to find mates, host plant odors to find hosts, and aggregate pheromones to find partners. Tentacles are the main olfactory organs for insects to feel these odorous substances. Electron potential electrogram (EAG) is a very important biometric method in the rapid detection of the reactivity and sensitivity of antennae to odor. Since EAG technology was invented by Schneider in 1957, due to its high sensitivity and selectivity, EAG technology has been widely used in the study of insect olfaction, and has become one of the most powerful tools for the bioassay of insect pheromones and other volatile information compounds . Principle: There are a variety of chemical sensors on the antennae of insects, especially hair-shaped sensors and tapered sensors, which mainly sense the chemical odor in the environment. The odor enters the sensory lymph through micropores on the sensor, and combines with the binding protein in the lymph to form a complex. The complex then interacts with the dendritic membrane of the sensory cell to generate an action potential, causing behavioral responses of insects. Each sensory cell on the antennae can be regarded as a power supply and a resistance. Generally, the power supply voltage is only a few microvolts to a few millivolts, and the resistance is several megaohms. There are many such sensory cells between the base and end of the antennae. When stimulated by active odor compounds, a large number of sensory cells will produce corresponding electrophysiological responses. After recording at the base and end of the antennae, a total potential change can be obtained. This is the antenna potential diagram. Device: analysis: Applications: Related papers: Travel Mug,Tea Cup,Special Shape Coffee Mug,Steel Lid Bamboo Coffee Mug NINGBO GECEN PROMOTION & GIFT CO.,LTD. , https://www.nbgecen.com
The EAG device is mainly composed of a micro-manipulator, an amplifier, an odor stimulus control device, and a tentacle potential recording display output device. The two electrodes connected to the antennae are fixed on the micromanipulator, and its position can be adjusted by the regulator. The amplifier is equipped with low-pass, high-pass filters and level discriminator filters, which are used to recognize action potentials and perform the function of frequency / voltage converter. The stimulating odor control device generates a continuous air flow blowing through the tentacles through the odor mixing tube, and the foot pedal is used to control the trigger of the air flow.
The recorded tentacle potential is the sum of the action potentials of all the receptors on the antenna that are stimulated by odor. Therefore, according to the relative magnitude of the potential change, it is possible to infer the number of corresponding odor receptors and the sensitivity of the receptors to odor. The rising phase, falling phase and continuous phase of the EAG peak can reflect some relevant information in the process of antenna feel. The ascending phase is related to the process of depolarization of sensor cells, while the descending phase is related to the inactivation of odor compounds. Different odor compounds cause different EAG waveforms, namely different ascending phase, descending phase, and sustained equal kinetic parameters, reflecting the different sensitivity of antennae receptors to different odor compounds, and the difference in the process and time of inactivation of different odor compounds.
EAG can be combined with gas chromatography (GC-EAG) to identify the components of plant odors and pheromones, and speculate on the types and structures of plant odors and pheromones. In this example, GC-EAG technology was used to analyze the damage of Brussels sprouts (Brussels sprouts) by caterpillars. Studies have confirmed that Brussels sprouts will release pheromones that attract natural enemies of pests when they are infested by them. Table 7 in the attachment is the EAG reaction caused by the chemical substances released by Brussels sprouts after being attacked by P. rapae (Cotesia Rubecula) (top half). Each peak in the lower half represents a released chemical substance. Figure 8 in the appendix shows the EAG reaction of the natural enemy Cotsia Glomerata to the chemical released by Brussels sprouts after being attacked by P. brassicae. The chemical substances released by Brussels sprouts are identified by GC-MS and listed in the attached icon VI.
(GC-EAG-analysis of volatiles from Brussels sprouts plants
damaged by two species of Pieris caterpillars: olfactory
receptive range of a specialist and a generalist parasitoid wasp
species, Chemoecology, Volume 12, Number 4, 169-176, 2002)
1. Yongjun Du, Guy M. Poppy, Wilf Powell, John A. Pickett, Lester J. Wadhams and Christine M. Woodcock, Identification of
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2. Luciane G. Batista-Pereira; João B. Fernandes *; Arlene G. Corrêa; M. Fátima GF da Silva; Paulo C. Vieira,
Electrophysiological responses of eucalyptus brown looper Thyrinteina arnobia to essential oils of seven Eucalyptus species,
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Edson Rodrigues Filho and Orlando S. Ohashi, Electrophysiological Responses of Female and Male Hypsipyla grandella (Zeller)
to Swietenia macrophylla Essential Oils Journal of Chemical Ecology, Volume 29, Number 9, 2143-2151, 2003