Published: September 14th, 2018
To test the inhibitory effects of pharmacologic agents on phospholipase C (PLC) in different regions of the honeybee brain, we present a biochemical assay to measure PLC activity in those regions. This assay could be useful for comparing PLC activity among tissues, as well as among bees exhibiting different behaviors.
The honeybee is a model organism for evaluating complex behaviors and higher brain function, such as learning, memory, and division of labor. The mushroom body (MB) is a higher brain center proposed to be the neural substrate of complex honeybee behaviors. Although previous studies identified genes and proteins that are differentially expressed in the MBs and other brain regions, the activities of the proteins in each region are not yet fully understood. To reveal the functions of these proteins in the brain, pharmacologic analysis is a feasible approach, but it is first necessary to confirm that pharmacologic manipulations indeed alter the protein activity in these brain regions.
We previously identified a higher expression of genes encoding phospholipase C (PLC) in the MBs than in other brain regions, and pharmacologically assessed the involvement of PLC in honeybee behavior. In that study, we biochemically tested two pharmacologic agents and confirmed that they decreased PLC activity in the MBs and other brain regions. Here, we present a detailed description of how to detect PLC activity in honeybee brain homogenate. In this assay system, homogenates derived from different brain regions are reacted with a synthetic fluorogenic substrate, and fluorescence resulting from PLC activity is quantified and compared between brain regions. We also describe our evaluation of the inhibitory effects of certain drugs on PLC activity using the same system. Although this system is likely affected by other endogenous fluorescence compounds and/or the absorbance of the assay components and tissues, the measurement of PLC activity using this system is safer and easier than that using the traditional assay, which requires radiolabeled substrates. The simple procedure and manipulations allow us to examine PLC activity in the brains and other tissues of honeybees involved in different social tasks.
The European honeybee (Apis mellifera L.) is a eusocial insect, and female bees show caste-dependent reproduction and age-dependent division of labor. For example, in the sterile caste of bees referred to as 'workers', younger individuals feed the broods while older ones forage nectar and pollen outside the hive1. Learning and memory ability is critically important in the life of the honeybee, because foragers must repeatedly go back and forth between food sources and their nest and then communicate the locations of good food sources to their nestmates through dance communication1. Previous stu....
1. Capture of Foraging Honeybees
Protein Concentrations in Brain Homogenates:
We prepared homogenates using forager bees. The calculated protein concentrations in the original homogenates are shown in Figure 3. The approximate protein concentrations in the original homogenate were as follows: 1.5 mg/mL in the MBs and 2.3 mg/mL in other brain regions. We used two bees per lot and six lots were analyzed.
The biochemical examination of protein activity is profoundly important for understanding molecular signaling in the brain, because the activity of an enzyme is affected by various molecules, such as substrates and inhibitors, and can, thus, change along with animal behavior (e.g., learning and memory)5. In honeybee studies, enzymes such as cyclic AMP-dependent protein kinase A, cyclic GMP-dependent protein kinase, PKC, phosphorylated CaMKII, and adenylate cyclase are reported to be diffe.......
Figure 4B - 4D was modified from Suenami et al.24 with the permission of Biology Open. The authors are grateful to the publisher for the permission. This work was supported by the Human Frontier Science Program (RGY0077/2016) to Shota Suenami and Ryo Miyazaki.....
|Pierce BCA Protein Assay Kit
|The reagent kit for measurement of protein concentration
|Pierce Bovine Serum Albumin Standard Ampules 2mg/mL
|The standard samples used in BCA assay
|Dental wax used as dissection stage
|Stainless, solid head
|A fluorogenic substrate of PLC
|Low-volume, round-bottom plate in black color
|Gemini EM microplate reader
|Santa Cruz Biotechnology
|Santa Cruz Biotechnology
Copyright © 2024 MyJoVE Corporation. All rights reserved