( Nucleoside ( ( analogues ( ( ( ( ( ( ( ( stop ( ( the spread ) ( of HIV ) ) ) ( by ( inhibiting ( the ( viral ( replicating enzyme ) ) ) ) ) ) , ) ( reverse transcriptase ) ) , ) but ) ( ( ( show little ) ( to ( no effectiveness ) ) ) ( in ( preventing replication ) ) ) ) ( once ( ( the virus ) ( ( has successfully ) ( integrated ( into ( the ( host ( cell chromosome ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Nucleoside)) (VP (VBZ analogues) (VP (VP (VB stop) (NP (NP (DT the) (NN spread)) (PP (IN of) (NP (NNP HIV)))) (PP (IN by) (S (VP (VBG inhibiting) (NP (DT the) (JJ viral) (JJ replicating) (NN enzyme)))))) (, ,) (VP (VB reverse) (NP (NN transcriptase))) (, ,) (CC but) (VP (VB show) (NP (RB little)) (PP (TO to) (NP (DT no) (NN effectiveness))) (PP (IN in) (S (VP (VBG preventing) (NP (NN replication)))))) (SBAR (IN once) (S (NP (DT the) (NN virus)) (VP (VBZ has) (ADVP (RB successfully)) (VP (VBN integrated) (PP (IN into) (NP (DT the) (NN host) (NN cell) (NN chromosome))))))))) (. .)))
Nucleoside analogues stop the spread of HIV by inhibiting the viral replicating enzyme, reverse transcriptase, but show little to no effectiveness in preventing replication once the virus has successfully integrated into the host cell chromosome.
(ROOT (S (NP (NNP Tamiflu)) (VP (VBZ inhibits) (NP (NP (NN spread)) (PP (IN of) (NP (NN virus))))) (. .)))