Spermatozoon ultrastructure of hangingflies, Bittacus strigosus and Bittacus stigmaterus.

In the present study, spermatozoon ultrastructure was documented in two species of hangingflies, Bittacus strigosus Hagen (Mecoptera: Bittacidae) and B. stigmaterus Say. Structures considered important to phylogenetic assessment that were observed in B.

AhR2-mediated, CYP1A-independent cardiovascular toxicity in zebrafish (Danio rerio) embryos exposed to retene.

In the embryo-larval stages of fish, alkylphenanthrenes such as retene (7-isopropyl-1-methylphenanthrene) produce a suite of developmental abnormalities typical of exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), including pericardial and yolk sac edema, cardiovascular dysfunction, and skeletal deformities. To investigate the mechanism and target tissue of retene toxicity, we used observational, histological, and protein knockdown techniques in zebrafish (Danio rerio) embryos. The primary overt signs of toxicity are pericardial edema and reduced blood flow, first observed at 36 h post-fertilization (hpf).