| ultrastructural features of cystic and merogonic stages of hepatozoon sipedon (apicomplexa: adeleorina) in northern leopard frogs (rana pipiens) and northern water snakes (nerodia sipedon) from ontario, canada. | the cystic and merogonic stages of the haemogregarine hepatozoon sipedon, infecting northern water snakes (nerodia sipedon sipedon) and northern leopard frogs (rana pipiens), respectively, in ontario, canada, were investigated by transmission electron microscopy. cysts, which were observed in the liver of northern leopard frogs (rana pipiens) after these anurans ingested mosquitoes (culex pipiens) containing oocysts of the parasite, harboured two cystozoites, each of which contained a large crys ... | 1998 | 9703677 |
| morphology, ultrastructure and taxonomic status of toddia sp. in northern water snakes (nerodia sipedon sipedon) from ontario, canada. | inclusions characteristic of an infection caused by toddia sp. were found in the erythrocytes and erythroblasts of 15 of 26 northern water snakes (nerodia sipedon sipedon) collected near kingston, ontario, canada. erythrocytes contained translucent inclusions, small acidophilic bodies, and square-shaped crystalloid structures. erythrocytes infected with toddia sp. were more rounded than uninfected erythrocytes and had pycnotic nuclei. we observed icosahedral virus particles measuring 195 to 210 ... | 1994 | 8028100 |
| microgeographic population genetic structure in the northern water snake, nerodia sipedon sipedon detected using microsatellite dna loci. | we describe the isolation and genetic characterization of eight microsatellite dna loci from the northern water snake, nerodia sipedon sipedon and use these loci to analyse levels of genetic differentiation between local (< 2 km apart) populations of these snakes in ontario. these loci are variable, with expected heterozygosities ranging from 0.28 to 0.91, and can correctly exclude nonsires in parentage analyses with a high probability (0.998). population analyses reveal significant deviation fr ... | 1999 | 10065548 |
| polychlorinated biphenyls and organochlorine pesticides in plasma and the embryonic development in lake erie water snakes (nerodia sipedon insularum) from pelee island, ontario, canada (1999). | from three locations along a 34-km shoreline of pelee island, ontario, 30 gravid female lake erie water snakes (nerodia sipedon insularum) were sampled to determine the organochlorine (oc) contaminant levels in plasma and the number of live and dead embryos present in the body cavity. plasma was analyzed for 59 polychlorinated biphenyl (pcb) congeners and 14 organochlorine pesticides. concentrations of pesticides were low (< or =0.1 ng/g wet wt) in all snakes, but there was significant variation ... | 2006 | 16823523 |