Once they reach your respiratory lining, the viruses attach to a specific kind of cell receptor, called sialic acid.

一旦病毒进入你的呼吸系统，就会附着在一种叫做唾液酸的特定细胞受体上。

They then screened 2.1m of these mutant viruses to see which bind to sialic acid of the mammalian variety.

他们筛选了210万种突变病毒以找到能与哺乳动物细胞的唾液酸相接的病毒。

He found that N224K, Q226L and N158D all control areas in the head of the HA protein-ie, the hook-and probably help it attach to the mammalian flavour of sialic acid.

他发现N224K, Q226L和N158D这三种基因都能控制血凝素蛋白的头部—即爪部—且可能可以帮助血凝素与哺乳动物的唾液酸相连。

HA is the viral equivalent of a grappling hook: it lets the virus latch onto a cell by binding to substances called sialic acids that are found in receptors on the cell's surface.

它通过抓住一种位于细胞表面受体中称作唾液酸的物质而使病毒与细胞相黏附。