Schistosomes utilize proteinases to accomplish several activities such as tissue penetration, tissue digestion and evasion of host immune responses. Cathepsin L is a cysteine proteinase of the papain superfamily detected in their gut lumen which indicates that this enzyme contributes to the proteolysis of ingested hemoglobin. Due to the roles played in the schistosome biology, proteolytic enzymes are considered potential targets for developing and guiding antischistosomal therapies. In the present work, the cathepsin L1 cDNA coding of Schistosoma mansoni was cloned into the pAE vector that provides high-level expression of heterologous proteins in Escherichia coli. The recombinant protein was expressed as inclusion bodies, purified under denaturing conditions through nickel-charged chromatography and used for experimental animal vaccination. ELISA was performed with the pooled sera. Although this protein was shown to be immunogenic, mice immunized with three doses of recombinant protein plus aluminum hydroxide as adjuvant were not protected against S. mansoni infection.

Specimens of Biomphalaria tenagophila exposed to miracidia of Schistosoma mansoni were submitted to different desiccation periods as follows: group I: 24 h after exposure, desiccated for 28 days; group II: after cercariae elimination, desiccated for 7 days; group III: 21 days after exposure, desiccated for 7 days; group IV: 14 days after exposure, desiccated for 14 days; group V: 7 days after exposure, desiccated for 21 days. From the obtained data it was verified that desiccation was not capable of interrupting the development of larvae of S. mansoni in mollusks. A delay in the development of S. mansoni larvae in groups I, III, IV and V was observed. A pause was verified in the development of S. mansoni larvae in groups II, III, IV and V. Some larvae, in groups I, III, IV and V, did not suffer as a result of desiccation and continued their development. Larvae in the cercariae stage were shown to be more sensitive to desiccation. It was possible to obtain clearing of mollusks infected by sporocysts II and cercariae using a period of 7 days of desiccation.

Biomphalaria tenagophila é um hermafrodita simultâneo cujo investimento na função masculina foi avaliado pelo crescimento de seus órgãos sexuais em relação ao diâmetro da concha. Foram criadas novas técnicas para medir órgãos reprodutivos, sem aparentes distorções, e contar folículos do ovoteste. Durante o crescimento de espécimes sexualmente maduros de B. tenagophila, cresceu o número de folículos do ovoteste, mas seus números máximos e mínimos são menores do que os citados na literatura. O número de divertículos da próstata e de folículos do ovoteste de B. glabrata é maior do que o de B. tenagophila. Embora o comprimento do ovoteste, da próstata, da bainha do pênis e da glândula mucípara-ootecal variassem durante o crescimento do caramujo, não variou significativamente o número de divertículos da próstata.

Biomphalaria tenagophila is a simultaneous hermaphrodite whose's male function was evaluated by the growth of the sex organs in relation to the shell diameter. New techniques were applied to measure reproductive organs without apparent distorsion and to count individual ovotestis follicles. During the growth of sexually mature specimens of B. tenagophila the ovotestis follicles increased in number, but the maximum and minimum values are smaller than the ones found in the literature. The number of B. glabrata prostate diverticula and ovotestis follicles were greater than that of B. tenagophila. Although the length of ovotestis, prostate, penial sheath and muciparous-oothecal gland varied during B. tenagophila's growth, the number of prostate diverticula remained signifcantly stable.