( ( This mechanism ) ( ( ( is ( useful ( to ( the virus ) ) ) ) ( as ( it ( allows ( the ( virus ( to ( ( spread ( from infected ) ) ( to ( uninfected cells ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This) (NN mechanism)) (VP (VBZ is) (ADJP (JJ useful) (PP (TO to) (NP (DT the) (NN virus)))) (SBAR (IN as) (S (NP (PRP it)) (VP (VBZ allows) (NP (DT the) (NN virus) (S (VP (TO to) (VP (VB spread) (PP (IN from) (ADJP (JJ infected))) (PP (TO to) (NP (JJ uninfected) (NNS cells))))))))))) (. .)))
This mechanism is useful to the virus as it allows the virus to spread from infected to uninfected cells.
(ROOT (S (NP (NNP Tamiflu)) (VP (VBZ inhibits) (NP (NP (NN spread)) (PP (IN of) (NP (NN virus))))) (. .)))