Document Type : Original Article
Authors
1
Department OF Environmental Researches and Medical Malacology, Theodor Bilharz Research Institute, Egypt.
2
Regional Center for Mycology and Biotechnology, Al-Azhar University, Cairo, Egypt.
Abstract
Silver nanoparticles (AgPNs) extracts were prepared from seven Seven fungal isolates were evaluated through measuring their toxicity against Biomphalaria alexandrina snails. The effects of the two promising Paecilomyces variotii and Aspergillus niger AgNPs sublethal concentrations (LC10 & LC25) on the levels of steroid sex hormones, liver enzymes, total protein, lipids, albumin, glucose, total and differential count of hemocytes and morphology of hemocytes, oocytes and sperms were studied in this work. The short period of snails’ exposure (24h) to the two fungal AgNPs resulted in significant decrease in the levels of progesterone in B. alexandrina. The level of testosterone hormone showed significant increase in snails exposed to P. variotii AgNPs while no significant change was recorded at the exposure to A. niger AgNPs. Also, estradiol hormone concentration increased significantly in this investigation with the increase of the
concentration of the two tested compounds. In addition, significant elevation in ALT, AST and Alkaline phosphatase was recorded. The total number of the hematocytes increased significantly by17.4-47.8%. Snails’ granulocytes were reduced by 19.1- 43.8%, while hyalinocytes increased by 63.6-354.5%. The exposure of B. alexandrina to LC25 of both P. variotii and A. niger AgNPs showed apoptotic hemolymph cells, fragmented, vacuolated and degenerated cytoplasm, shrunken nucleus and phagocytosis in the light microscopy photographs of the hemocytes. Besides, the photographs showed also, abnormal nuclear division, degeneration and large fat vacuoles in the cytoplasm and swallowed atretic oocytes. Also, the photographs showed dead sperm head separated from its tail, other sperms showed abnormal swallowed head with severely nodded tail, dead sperms with wrinkled tails, hyperplasia and necrotic sperm heads led to overlapping of
tails. In conclusion, applying the biosynthesized compounds which led to destruction of blood cells (the immune system), ova and sperms (the reproductive system) of snails is an important effective step to control schistosomiasis.
Keywords
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