Zoomorphology

, Volume 110, Issue 3, pp 165–174 | Cite as

Alternative modes of asexual reproduction inTrichoplax adhaerens (Placozoa)

  • Martin Thiemann
  • August Ruthmann
Article

Summary

Hollow swarmers are budded off at the dorsal surface ofTrichoplax and are covered by dorsal epithelium. Their inner cavity is lined with the flagellated cells of the ventral epithelium. There is no indication that the fiber cells included between the epithelia take any part either in morphologenesis or the separation of the bud from the mother animal. The early primordium forms in the interspace. A single layer of cells derived from both epithelia surrounds a cavity filled with granular matter that stains like proteins. The latter is used up during the floating phase of the swarmers that may last for a week. After settling at the bottom, the hollow sphere opens at one point. The concave ventral epithelium gradually flattens as more cells become incorporated in it. The latter form new flagella and flagellar pits. More frequently found than swarmers are small spherical forms that are unable to float and possess a distinct polarity. Their upper half is covered by dorsal epithelium and their lower half by ventral epithelium. Large fiber cells are in the center. Their site and mode of formation is unknown. Rarely observed are dorsal stolons whose bulbous end flattens upon touching the substrate. Since they are totally covered by the flat cells of the dorsal epithelium, they may have to undergo a transformation, like the hollow swarmers, to bring the ventral epithelium into contact with the substrate.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Allen RE (1980) Staining protein in isoelectric focusing gels with fast green. Anal Biochem 104:494Google Scholar
  2. Behrendt G, Ruthmann A (1986) The cytoskeleton of the fiber cells ofTrichoplax adhaerens (Placozoa). Zoomorphology 106:123–130Google Scholar
  3. Birnstein VJ (1989) On the karyotype ofTrichoplax sp. (Placozoa). Biol Zentralbl 108:63–67Google Scholar
  4. Grell KG (1974) Vom Einzeller zum Vielzeller. Hundert Jahre Gastraea-Theorie. Biologie in unserer Zeit 4:65–71Google Scholar
  5. Grell KG, Benwitz G (1971) Die Ultrastruktur vonTrichoplax adhaerens F.E. Schulze. Cytobiologie 4:216–240Google Scholar
  6. Grell KG, Benwitz G (1981) Ergänzende Untersuchungen zur Ultrastruktur vonTrichoplax adhaerens F.E. Schulze (Placozoa). Zoomorphology 98:47–67Google Scholar
  7. Ivanov DL, Malakhov VV, Tzetlin AB (1980) Fine morphology and ultrastructure of a primitive multicellular organism (Trichoplax sp. I. Morphology of adult and vagrants by the data of scanning electron microscopy (in Russian). Zool J 59:1765–1769Google Scholar
  8. Ruthmann A (1977) Cell differentiation, DNA content and chromosomes ofTrichoplax adhaerens F.E. Schulze. Cytobiologie 15:58–64Google Scholar
  9. Ruthmann A, Terwelp U (1979) Disaggregation and reaggregation of cells of the primitive metazoonTrichoplax adhaerens. Differentiation 13:185–198Google Scholar
  10. Ruthmann A, Behrendt G, Wahl R (1986) The ventral epithelium ofTrichoplax adhaerens (Placozoa): Cytoskeletal structures, cell contacts and endocytosis. Zoomorphology 106:115–122Google Scholar
  11. Schulze FE (1891) ÜberTrichoplax adhaerens. Physikal Abh Kgl Akad Wiss Berlin 1–23Google Scholar
  12. Schwartz V (1984) Das radiopolare Differenzierungsmuster beiTrichoplax adhaerens F.E. Schulze (Placozoa). Z Naturforsch 39c:818–832Google Scholar
  13. Thiemann M, Ruthmann A (1988)Trichoplax adhaerens F.E. Schulze (Placozoa): The formation of swarmers. Z Naturforsch 43c:955–957Google Scholar
  14. Thiemann M, Ruthmann A (1989) Microfilaments and microtubules in isolated fiber cells ofTrichoplax adhaerens (Placozoa). Zoomorphology 109:89–96Google Scholar

Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • Martin Thiemann
    • 1
  • August Ruthmann
    • 1
  1. 1.Lehrstuhl für Zellmorphologie, Fakultät für BiologieRuhr-Universität BochumBochum 1Federal Republic of Germany

Personalised recommendations