ISSN:
1615-6102
Keywords:
Harveyella
;
Host-parasite
;
Odonthalia
;
Pit connection
;
Red algae
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Harveyella mirabilis is a colourless red algal alloparasite which grows on and within its photosynthetic hostOdonthalia floccosa. Cells ofHarveyella establish secondary pit connections (PCs) with other parasite cells and with cells of the host. Small, uninucleate conjunctor cells are produced by parasite cells and remain connected to them by PCs. Conjunctor cells may fuse with either an adjacent host or parasite cell, with the parasite-conjunctor cell PC becoming either a host-parasite or parasite-parasite secondary PC. Occasionally the conjunctor cell does not fuse with an adjacent cell (either host or parasite) and degenerates. The secondary pit plug which forms between a parasite cell and its conjunctor cell always develops with two structurally distinct surfaces characteristic of a host-parasite pit plug. Only if the conjunctor cell fuses with another parasite cell will the structure of the pit plug be altered to that of a parasite-parasite pit plug. Fungal hyphae also invade the region of infection, andHarveyella cells respond by producing nonfunctional conjunctor cells that grow towards adjacent hyphae. Evidence suggests that secondary PCs may be induced to form mechanically, by the physical presence of another cell, rather than in direct response to a message received from an adjacent cell. The mechanism of secondary PC formation described here is similar to that reported for the closely related alloparasiteHolmsella and may be common to a number of red algal parasitic associations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01287818
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