Colchicum Ritchii flower: a new molluscicidal plant for Biomphalaria alexandrina snails and the infective stages of Schistosoma mansoni

Evaluation of the Effects of Papain on Schistosoma mansoni: Miracidial Infection Capacity, Infection Prevalence, Cercarial Shedding and Molecular Changes in Biomphalaria alexandrina

PURPOSE

The aim of the present study is to assess the molluscicidal, larvicidal and genotoxicological activities of papain and how it can affect the host-parasite interactions.

METHODS

Toxicity of papain on snails by making series of concentrations to calculate LC50, and then study its larvicide effect on the free larval stages of S. mansoni and infection rate of snails.

RESULTS

Papain has a molluscicidal activity on adult snails of Biomphalaria alexandrina with a lethal concentration LC50 equals to 43.1 mg/L. In addition, it has activity on miracidia with half Lethal time (LT50) of 16.11 min., and on cercariae with 12.1 min. compared to control ones. The sub lethal concentration LC10 and LC25 (6.9 or 24.1 mg/L, respectively) decreased the survival rate of snails at the first cercarial shedding, the rate of infection, the average total number of cercariae per snail, the shedding period and the life span of snails, while the prepatent period was significantly increased than the control ones. The morphological alterations in cercariae after exposure to papain were occurred where the cercariae lacked motility and some had a dark tail with complete detachment of head and tail. Compared to the control group, the levels of cytochrome oxidase subunit I (COI) and (ND1) genes significantly decreased in snails after exposure to papain.

CONCLUSIONS

Papain could be used as a potential molluscicide for elimination of schistosomiasis and decrease its transmission and deterioration of host-parasite interaction.

Biomonitoring of manganese metal pollution in water and its impacts on biological activities of Biomphalaria alexandrina snail and larvicidal potencies

Metal pollution has many dangerous environmental and human health consequences due to the bioaccumulation in the tissues. The present study aims to measure the bioaccumulation factor of the manganese (Mn) heavy metal in Biomphalaria alexandrina snails' tissues and water samples. The current results showed the concentration of Mn heavy metal in water (87.5 mg/l) and its bioaccumulation factor in Helisoma duryi tissue was higher than that in tissues of Physa acuta and B. alexandrina snails. Results showed that 87.5 mg/l Mn concentration had miracidicidal and cercaricidal activities. Also, this concentration decreased the mean total number of the hemocytes after exposure for 24 h or 48 h, while increasing both the mean mortality and phagocytic indices of the hemocytes of exposed snails. It caused alterations in the cytomorphology of the hemocytes of exposed snails after 24 or 48 h, where the granulocytes had irregular cell membranes and formed pseudopodia. Besides, levels of testosterone (T) and estradiol (E) were increased after exposure to 87.5 mg/l Mn metal compared to the control group. Also, it increased MDA (malonaldehyde) and TAC (total antioxidant capacity) contents, while decreasing SOD (superoxide dismutase). Besides, it caused significant histopathological damages in both hermaphrodite and digestive glands, represented in the degeneration of the gonadal, digestive, secretory cells, and the connective tissues. Therefore, B. alexandrina might be used as a sensitive bioindicator of pollution with Mn heavy metal to avoid ethics rules; besides, they are readily available and large in number.

Histopathological, Immunohistochemical, Biochemical, and In Silico Molecular Docking Study of Fungal-Mediated Selenium Oxide Nanoparticles on Biomphalaria alexandrina (Ehrenberg, 1831) Snails

Daphnia magna and freshwater snails are used as delicate bioindicators of contaminated aquatic habitats. Due to their distinctive characteristics, selenium oxide nanoparticles (SeONPs) have received interest regarding their possible implications on aquatic environments. The current study attempted to investigate the probable mechanisms of fungal-mediated selenium nanoparticles' ecotoxicological effects on freshwater Biomphalaria alexandrina snails and Daphnia magna. SeONPs revealed a toxicological impact on D. magna, with a half-lethal concentration (LC₅₀) of 1.62 mg/L after 24 h and 1.08 mg/L after 48 h. Survival, fecundity, and reproductive rate were decreased in B. alexandrina snails exposed to SeONPs. Furthermore, the aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were markedly elevated, while albumin and total protein levels decreased. Histopathological damage in the hermaphrodite and digestive glands was detected by light, electron microscopy, and immunohistochemistry studies. The molecular docking study revealed interactions of selenium oxide with the ALT and AST. In conclusion, B. alexandrina snails and D. magna could be employed as bioindicators of selenium nanomaterial pollution in aquatic ecosystems. This study emphasizes the possible ecological effects of releasing SeONPs into aquatic habitats, which could serve as motivation for regulatory organizations to monitor and control the use and disposal of SeONPs in industry.