Exactly 100 years ago, F.R. Lillie reported chemotaxis in animal sperm for the first time (Lillie, 1912). Chemo-taxis refers to the directed movement of a cell or organism to the source of a chemical gradient; the chemical agent that elicits this movement is called a chemoattrac-tant. Chemotaxis had previously been shown by Pfeffer (1884) for fern spermatozoids; however, attempts to demonstrate...

Fertilization in the brown marine algae known as fucoids, is oogamous. The naked egg cell (80 micron diam.) is fertilized by small biflagellate spermatozoids and both monoecious and dioecious species are found. Fertilization is highly species-specific and this appears to be controlled during plasmogamy. Following fusion of egg and sperm, a rapid (less than 1 min) release of polyuronide cell wal...

The accumulation of hepatotoxic microcystins (MCs) in gastropods has been demonstrated to be higher following grazing of toxic cyanobacteria than from MCs dissolved in ambient water. Previous studies, however, did not adequately consider MCs covalently bound to protein phosphatases, which may represent a considerably part of the MC body burden. Thus, using an immunohistochemical method, we exam...

Background: Infertility is a major clinical and worldwide reproductive problem that affects approximately 15% of young couples. The male factors are responsible for periphery 50 percent of these cases. Recently, the generation of oxidative stress, also described as an imbalance between the production of Reactive oxygen species (ROS) and the body’s antioxidant defence mechanisms, in the male rep...

conclusions buprenorphine is more suitable for treating opiate addiction in males since it does not affect normal testicular structure and function. results stereological analysis of rat testes showed no significant effect of methadone and buprenorphine administration on the testis volume (p > 0.05). however, microscopic stud­ies of rat tissues in the methadone-administered group showed atrophi...

Much attention is currently being devoted to the nature of the mechanisms in the cytoplasm which control and orient the deposition of polysaccharide microfibrils on the inner surface of the plant cell wall (1-4). We have approached the question of cytoplasmic participation in wall deposition by studying the fine structure of cells undergoing rapid secondary wall formation. Our study has demonst...