( ( During ( penetration ( of ( ( host cells ) ( by ( ( sporozoites or ) merozoites ) ) ) ) ) ) ( , ( ( an ( electron-dense layer ) ) ( ( ( ( forms ( at ( ( the point ) ( of attachment ) ) ) ) and ) ( ( is ( morphologically reminiscent ) ) ( of ( a desmosome ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN During) (NP (NP (NN penetration)) (PP (IN of) (NP (NP (NN host) (NNS cells)) (PP (IN by) (NP (NNS sporozoites) (CC or) (NNS merozoites))))))) (, ,) (NP (DT an) (JJ electron-dense) (NN layer)) (VP (VP (VBZ forms) (PP (IN at) (NP (NP (DT the) (NN point)) (PP (IN of) (NP (NN attachment)))))) (CC and) (VP (VBZ is) (ADJP (RB morphologically) (JJ reminiscent)) (PP (IN of) (NP (DT a) (NN desmosome))))) (. .)))
During penetration of host cells by sporozoites or merozoites, an electron-dense layer forms at the point of attachment and is morphologically reminiscent of a desmosome.
(ROOT (S (NP (NNS Sporozoites)) (VP (VBP are) (NP (NP (DT the) (NNS cells)) (VP (VBN caused) (SBAR (IN that) (S (NP (NNS parasites)) (VP (VBD spread) (PP (IN through) (NP (PRP$ their) (NN host))))))))) (. .)))