一个常识，当细胞菌进入机体内后，会产生两种不同的结果，一是导致疾病，二是与机体产生共生关系，这会导致有益的结果，如肠道内益生菌群。那么为什么会出现这种完全不同的现象呢？最新出版的Science文章揭示这个秘密。PGN和脂多糖LPS在其中起到关键作用。
To date, molecules conserved among microbes, such as LPS and PGN, have been collectively described as "pathogen"-associated molecular patterns (PAMPs) (1). However, the majority of animal-microbe interactions are benign or mutualistic, raising the question: What role might such factors play in other types of host-microbe associations?
The reciprocal dialogue between partners in benign host-symbiont associations has been shown to be important for host tissue maturation (2–4), although the identification of the bacterial signals involved has proven elusive. The symbiosis between the Hawaiian bobtail squid E. scolopes and the luminous, Gram-negative bacterium V. fischeri offers the opportunity to decipher experimentally the precise dialogue between host and microbe partners. In this system, the bacterium colonizes epithelium-lined crypts within the host's light-emitting organ as a monospecific, extracellular symbiont
