MmpL3-IN-6

Membrane protein extraction with detergents and chaotropes solubilizes lipid-bilayer-associated proteins by disrupting protein-lipid and protein-protein interactions while maintaining proteins in a soluble state for downstream electrophoresis, purification, or mass spectrometry. Chaotropes such as urea and thiourea improve solubilization of difficult proteins, while nonionic and zwitterionic detergents such as CHAPS, ASB-14, SB 3-10, MEGA-10, dodecyl maltoside, and Triton X-100 differ in extraction efficiency depending on sample type and membrane protein properties.

The LIVE/DEAD bacterial viability staining method is based on differential permeability of nucleic-acid-binding fluorescent dyes, most commonly SYTO 9 and propidium iodide (PI), which enables discrimination of bacterial populations with intact versus compromised cytoplasmic membranes. SYTO 9 penetrates both intact and damaged bacterial membranes and binds nucleic acids to produce green fluorescence, whereas propidium iodide penetrates only cells with compromised membranes and fluoresces red while also reducing SYTO 9 signal through competitive binding and fluorescence interactions. The resulting fluorescence pattern is interpreted as a proxy for membrane integrity, which is widely used as an indicator of bacterial viability in microscopy, flow cytometry, and spectroscopic platforms. However, mechanistic studies show that SYTO 9 and PI interactions involve displacement and fluorescence resonance energy transfer effects, which can influence signal interpretation depending on dye ratios a