In Vitro Disassembly of the Influenza A Virus Core Using pH-Controlled Gradient Centrifugation

Take centrifugation tubes containing detergent-free glycerol.
For the control sample, add high-concentration, detergent-free glycerol at neutral pH.
For test samples, add high-concentration glycerol containing detergent, adjusted to different pH values.
Overlay the influenza A virus (IAV), containing a lipid envelope and a core composed of matrix protein and ribonucleoproteins.
Perform ultracentrifugation.
In the control, viruses pass through the detergent-free gradient and sediment as intact virions.
In the test samples, detergent in the lower layer solubilizes the viral envelope without disrupting the core.
At neutral pH, the intact core remains stable and sediments.
At mildly acidic pH, which mimics early endosomal conditions, the matrix protein dissociates, leaving the ribonucleoproteins to sediment.
At a more acidic pH, which mimics late endosomal conditions, the viral core fully disassembles, leaving no components to sediment.
This enables in vitro analysis of the IAV core disassembly under different pH conditions.

Using a five-milliliter syringe and a needle, add three milliliters of 15% glycerol solution to six ultraclear centrifugation tubes. Wash the needle in doubly-distilled water