美国国立卫生研究院的科学家在3月2日《自然—化学生物学》（Nature Chemical Biology）杂志在线版上报告说，他们利用核磁共振成像技术对流感病毒进行研究后发现，流感病毒表面被一层脂类物质所包裹。在温暖环境中，这层物质是液态，病毒如果不处于人或动物体内就会死亡。在寒冷的冬季，随着气温不断降低，这层物质会逐渐凝固变硬而对病毒起到保护作用，但这层物质会在病毒进入人的呼吸道后融化，病毒因此得以感染人体细胞。
AbstractUsing linewidth and spinning sideband intensities of lipid hydrocarbon chain resonances in proton magic angle spinning NMR spectra, we detected the temperature-dependent phase state of naturally occurring lipids of intact influenza virus without exogenous probes. Increasingly, below 41 °C ordered and disordered lipid domains coexisted for the viral envelope and extracts thereof. At 22 °C much lipid was in a gel phase, the fraction of which reversibly increased with cholesterol depletion. Diffusion measurements and fluorescence microscopy independently confirmed the existence of gel-phase domains. Thus the existence of ordered regions of lipids in biological membranes is now demonstrated. Above the physiological temperatures of influenza infection, the physical properties of viral envelope lipids, regardless of protein content, were indistinguishable from those of the disordered fraction. Viral fusion appears to be uncorrelated to ordered lipid content. Lipid ordering may contribute to viral stability at lower temperatures, which has recently been found to be critical for airborne transmission.
