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Hematological analysis of the ascidian Botrylloides leachii (Savigny, 1816) during whole-body regeneration

  • Blanchoud, Simon Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand - Department of Biology, University of Fribourg, Switzerland
  • Zondag, Lisa Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
  • Lamare, Miles D. Department of Marine Science, Division of Sciences, University of Otago, Dunedin, New Zealand
  • Wilson, Megan J. Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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    01.06.2017
Published in:
  • The Biological Bulletin. - 2017, vol. 232, no. 3, p. 143–157
Botrylloides leachii
hemocytes
hemolymph flow
histology
whole-body regeneration
English Whole-body regeneration (WBR)—the formation of an entire adult from only a small fragment of its own tissue—is extremely rare among chordates. Exceptionally, in the colonial ascidian Botrylloides leachii (Savigny, 1816) a fully functional adult is formed from their common vascular system after ablation of all adults from the colony in just 10 d, thanks to their high blastogenetic potential. While previous studies have identified key genetic markers and morphological changes, no study has yet focused on the hematological aspects of regeneration despite the major involvement of the remaining vascular system and the contained hemocytes in this process. To dissect this process, we analyzed colony blood flow patterns using time-lapse microscopy to obtain a quantitative description of the velocity, reversal pattern, and average distance traveled by hemocytes. We also observed that flows present during regeneration are powered by temporally and spatially synchronized contractions of the terminal ampullae. In addition, we revised previous studies of B. leachii hematology as well as asexual development using histological sectioning and compared the role played by hemocytes during WBR. We found that regeneration starts with a rapid healing response characterized by hemocyte aggregation and infiltration of immunocytes, followed by increased activity of hemoblasts, recruitment of macrophage-like cells for clearing the tissues of debris, and their subsequent disappearance from the circulation concomitant with the maturation of a single regenerated adult. Overall, we provide a detailed account of the hematological properties of regenerating B. leachii colonies, providing novel lines of inquiry toward the decipherment of regeneration in chordates.
Faculty
Faculté des sciences et de médecine
Department
Département de Biologie
Language
  • English
Classification
Biological sciences
License
License undefined
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Persistent URL
https://folia.unifr.ch/unifr/documents/307442
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