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Fungi: Oomycota



Saprolegnia declina Humphrey-parasitica (a.k.a. Coker Complex)


A. Species Name


  • Agaricus xanthodermus

B. Native Enviroment


  • Saprolegnia dwells in freshwater environments and bodies of aquatic organisms.
  • They invade the body of another organism to feed. "Oomycota" means "egg fungi".
  • This refers to the large round oogonia, structures containing the female gametes.

C. Characteristics of the Organism


  • Saprolegnia has a complex life cycle, which includes both sexual and asexual reproduction. A Saprolegnia nucleus contains two sets of genetic information.
  • Saprolegnias are oogamous, they produce both eggs and sperm. When the saprolegnias go through sexual reproduction, the sperm and egg combines and motile zoospores are produced.
  • They bear two dissimilar flagella, one with mastigonemes. When Saprolegnia goes through asexual reproduction, zoospores are released. These zoospores germinate and encyst to release more zoospores through a cycle called "polyplanetism".
  • During this phase, the zoospores attempt to find a host (a fish). They are considered to be the infectious spore of Saprolegnia. When zoospores find a host, it releases hairs to attach onto the host.
  • These hairs are also used for buoyancy and used to recognize other fungal hosts.

D. Adaptations to the Enviroment


  • In order to adapt to aquatic environment, the saprolegnia formed spores that possess flagellums. The flagellums help the spores swim and find hosts & food.
  • WIthout the adaptation they would be unable to reporoduce

E. Ecological and Medical Roles


  • The water mold Saprolegnia causes Saprolegniasis on fish which cause problems when the water is rather stagnant, as in aquaria or fish farms, or at high population densities, such as when salmon swim upstream to spawn.
  • Other species of Saprolegnia are parasitic on aquatic invertebrates such as rotifers, nematodes, and arthropods, and on diatoms.

F. A Picture or Sample of the Organism


Three Images of Saprolegnia declina Humphrey-parasitica

oomycota oomycota oomycota

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