Spermiogenesis in the Australian cockatiel Nymphicus hollandicus.

Information on the ultrastructure of parrot spermatids and spermatozoa is limited to only four species with no comprehensive study of spermiogenesis conducted within the order Psittaciformes. The present study was undertaken to describe the development of the cockatiel spermatid using electron microscopy. Four phases of spermatid maturation were documented on the basis of nuclear morphology, development of the acrosome, perforatorium, and axial filament.

Light and electron microscopy observations of embryogenesis and egg development in the human liver fluke, Opisthorchis viverrini (Platyhelminthes, Digenea).

Eggs of most species digenean flukes hatch in the external environment to liberate larvae that seek and penetrate a snail intermediate host. Those of the human liver flukes, Opisthorchis viverrini, hatch within the gastrointestinal canal of their snail hosts. While adult parasites are primarily responsible for the pathology in cases of human opisthorchiasis, their eggs also contribute by inducing granulomata and in serving as nidi for gallstone formation.

A cytochrome b561 with ferric reductase activity from the parasitic blood fluke, Schistosoma japonicum.

Background: Iron has an integral role in numerous cellular reactions and is required by virtually all organisms. In physiological conditions, iron is abundant in a largely insoluble ferric state. Ferric reductases are an essential component of iron uptake by cells, reducing iron to the soluble ferrous form.

Exposed proteins of the Schistosoma japonicum tegument.

The ability of the mammalian blood fluke Schistosoma japonicum to survive in the inhospitable environment of the mammalian bloodstream can be attributed, at least in part, to its host-exposed outer surface, called the tegument. The tegument is a dynamic organ and is involved in nutrition, immune evasion and modulation, excretion, osmoregulation and signal transduction. Given its importance for parasite survival, proteins exposed to the host at the surface of the tegument are ideal targets for the development of vaccines and drugs.