ISSN:
1432-0703
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
,
Medicine
Notes:
Abstract Freshwater clams,Anodonta cygnea, were treated during three months with the chitin-inhibitor, diflubenzuron (Dimilin® PH 60-40), suspended in water at a concentration of 200 mg/L. Cytochemical observations, carried out on the outer mantle epithelium (OME) of the treated and control animals, showed secretory cells with a periodic-acid Schiff (PAS) positive reaction and a negative reaction to enzymatic hydrolysis by amylase. However, morphological observations by scanning electron microscopy (SEM) showed that diflubenzuron strongly affects the normal calcification process on the lamellar layer of the shell, since the calcareous crystals do not form continuous layers, but rather disintegrated layers. These observations suggest that diflubenzuron may block the polycondensation reactions to chitin chains in the OME secretory cells of the freshwater clam,Anodonta cygnea, producing unpolymerized chitin (unstablized chitin) only. Diflubenzuron suspended at this concentration (200 mg/L), is not directly toxic to freshwater clam,Anodonta cygnea; however, a more persistent (chronic) exposure to this chemical compound may render the shell breakable.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01059810
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