1 / 12

Completion of the Rhizocephalan Life-cycle

Completion of the Rhizocephalan Life-cycle. Joshua Sabey BIOL 4800. Rhizocephalan. Free-living stages Nauplius Cypris. Rhizocephalan. Sacculina externa. Rhizocephalan.

Download Presentation

Completion of the Rhizocephalan Life-cycle

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Completion of the Rhizocephalan Life-cycle Joshua Sabey BIOL 4800

  2. Rhizocephalan • Free-living stages Nauplius Cypris

  3. Rhizocephalan • Sacculina externa

  4. Rhizocephalan • Dioecious (most barnacles hermaphroditic). • One host in the life-cycle. • Affects host morphologically, physiologically, and behaviorally. • Infection castrates host. • Crabs (even males) protect externa as if it was their own eggs. • Creates organism with host phenotype and parasite genotype.

  5. The Life-Cycle

  6. Before the Experiment • The nature of the material injected by the Kentrogon has been poorly understood for decades. • Any injection material seen in previous experiments disintegrated into numerous cells. • All experiments performed previously were done in vitro.

  7. Rearing and Infection Experiments • Purpose was to discover the nature of the material injected by the Kentrogon. • Kentrogon injection material was observed in vivo using light and electron microscopy. • Mud crabs, Rhithropanopeus harrisii, were parasitized with the sacculinid rhizocephalan Loxothylacus panopaei.

  8. Results: The Vermigon

  9. The Vermigon • A worm-like larva • Consists of a cuticle, epidermis and body of cells that will develop into the ovary. • The cuticle remains intact throughout development to an interna. • Has a distinct internal spiral across the entire length of its body. • The central spiral and actin fibers in the epidermis provide motility.

  10. The Life-Cycle

  11. The Vermigon • The kentrogon injects its vermigon into the blood spaces of the gills. • The vermigon migrates to the heart and then to the posterior region of the crab. • Once in the posterior, the vermigon develops a rootlet system and becomes an interna. • The interna matures and an externa emerges from the rear end of the crab.

  12. Conclusions • It is no longer assumed that the mature rhizocephalan develops from numerous undifferentiated cells in the kentrogon injection material. • The injection material is a whole vermigon consisting of a cuticle, epidermis, and cell bodies that become the uterus. • The vermigon stays as one unit during the maturation process.

More Related