five questions about microsporidia五个问题对小孢子虫目.pdfVIP

Pearls Five Questions about Microsporidia Patrick Keeling* Canadian Institute for Advanced Research, Botany Department, University of British Columbia, Vancouver, British Columbia, Canada What Are Microsporidia? Microsporidia are a diverse group of obligate intracellular eukaryotic parasites. There are approximately 1,300 formally described species in 160 genera [1], but this certainly represents a tiny fraction of the real diversity because most potential host lineages have been poorly surveyed. Nearly all microsporidia are known to infect animals, and some are responsible for a number of human diseases (13 species of microsporidia have been docu- mented to infect humans) predominantly associated with immune suppression [2]. They also infect several commercially important animal species such as bees, silk Figure 1. Light micrograph of Antonospora locustae with pressure-induced polar tube worms, and salmon, and various domesti- eversion. The scale bar is 10 um. (A) Many ungerminated spores (one example labeled U) and a cated mammals. They are thought to be few germinated spores, showing the residual spore wall (one example labeled G). (B) A especially common in insects and fish, germinated spore where the everted polar tube (PT) has extended far from the cell and can be seen to be many times the length of the spore. although most invertebrates have been so doi:10.1371/journal.ppat.1000489.g001 poorly surveyed this may change. Their infective stage is a thick-walled spore, illustrated by their tumultuous taxonomic ally the absence of many