( ( ( The significance ) ( of ( these changes ) ) ) ( ( ( lies ( in ( the demonstration ) ) ) ( that ( they ( were ( associated ( with ( ( the release ) ( of ( ( ( calcium ion ) , ) ( which ( ( as ( a ( ` ( second ( messenger ' ) ) ) ) ) ( , ( was ( ( proposed ( in turn ) ) ( to ( ( activate systems ) ( ( that ( direct development ) ) ( of ( ( the ( early stages ) ) ( of ( ( the parasite ) ( -LRB- ( 94 -RRB- ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN significance)) (PP (IN of) (NP (DT these) (NNS changes)))) (VP (VBZ lies) (PP (IN in) (NP (DT the) (NN demonstration))) (SBAR (IN that) (S (NP (PRP they)) (VP (VBD were) (VP (VBN associated) (PP (IN with) (NP (NP (DT the) (NN release)) (PP (IN of) (NP (NP (NN calcium) (NN ion)) (, ,) (SBAR (WHNP (WDT which)) (S (PP (IN as) (NP (DT a) (`` `) (JJ second) (NN messenger) ('' '))) (, ,) (VP (VBD was) (VP (VBN proposed) (PP (IN in) (NP (NN turn))) (S (VP (TO to) (VP (VB activate) (NP (NNS systems)) (NP (NP (DT that) (JJ direct) (NN development)) (PP (IN of) (NP (NP (DT the) (JJ early) (NNS stages)) (PP (IN of) (NP (NP (DT the) (NN parasite)) (PRN (-LRB- -LRB-) (NP (CD 94)) (-RRB- -RRB-))))))))))))))))))))))) (. .)))
The significance of these changes lies in the demonstration that they were associated with the release of calcium ion, which as a 'second messenger', was proposed in turn to activate systems that direct development of the early stages of the parasite (94).
(ROOT (S (NP (NNP Calcium) (NNP ion)) (VP (VBZ is) (NP (NP (DT an) (NN example)) (PP (IN of) (NP (DT a) (JJ second) (NN messenger))))) (. .)))
Calcium ion is an example of a second messenger.