WAR  of  the  MICROWORLDS  

How do I kill Thee?   Let me count the Ways!   (# 30)  click here for full list

Harposporium spirosporum: The serpentine conidia are acutely pointed at both ends with the opposite ends out of alignment such that they tend to rotate in the oesophagous of the host during ingestion.  Conidia are apparently attractive to rotifers as a food source but, as with some of the Harposprorium species that attack nematodes,  the conidia lodge in the oesophagous (before they reach the mastax of the host, see diagram below).   Here,  they germinate and fill the host with  filamentous, assimilative hyphae of variable and irregular width.   Eventually, assimilative hyphae fill the host and short unbranched conidiophores bearing clusters of flask-shaped conidiogenous cells (phialides) burst throught he walls of the infected host and produce a new generation of conidia.    In older infections conidiogenous cells often proliferate and produce a succession of phialidic mouths.  . (For further details on this species see -  Barron, G.L. 1986. A new Harposporium parasitic on bdelloid rotifers. Can. J. Bot. 64: 2379).

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Harposporium parasites of rotifers are obviously closely related morphologically and perhaps physiologically to the Harposporium species that attack nematodes.   It should be noted that in Haptoglossa (a sophisticated endoparasite) a single species  can attack  rotifers,  nematodes and possibly tardigrades suggesting that once past the wall these microfauna are similar inside.   It is possible (probable),therefore, that some of the species of Harposporium that attack rotifers will also be capable of attacking nematodes and vice versa.   This could easily be tested by cross feeding experiments.  Nice project!