Cell and Tissue Research

, Volume 325, Issue 3, pp 577–587 | Cite as

Immunogold-labeled S-phase neoblasts, total neoblast number, their distribution, and evidence for arrested neoblasts in Macrostomum lignano (Platyhelminthes, Rhabditophora)

  • A. Bode
  • W. Salvenmoser
  • K. Nimeth
  • M. Mahlknecht
  • Z. Adamski
  • R. M. Rieger
  • R. Peter
  • P. Ladurner
Regular Article


Neoblasts in Platyhelminthes are the only cells to proliferate and differentiate into all cell types. In Macrostomum lignano, the incorporation of 5′-bromo-2′-deoxyuridine (BrdU) in neoblasts confirmed the distribution of S-phase cells in two lateral bands. BrdU labeling for light and for transmission electron microscopy (TEM) identified three populations of proliferating cells: somatic neoblasts located between the epidermis and gastrodermis (mesodermal neoblasts), neoblasts located within the gastrodermis (gastrodermal neoblasts), and gonadal S-phase cells. In adults, three stages of mesodermal neoblasts (2, 2–3, and 3) defined by their ultrastructure were found. Stage 1 neoblasts where only seen in hatchlings. These stages either were phases within the S-phase of one neoblast pool or were subsequent stages of differentiating neoblasts, each with its own cell cycle. Regular TEM and immunogold labeling provided the basis for calculating the total number of neoblasts and the ratio of labeled to non-labeled neoblasts. Somatic neoblasts represented 6.5% of the total number of cells. Of these, 27% were labeled in S-phase. Of this fraction, 33% were in stage 2, 46% in stage 2–3, and 21% in stage 3. Immunogold labeling substantiated results concerning the differentiation of neoblasts into somatic cells. Non-labeled stage 2 neoblasts were present, even after a 2-week BrdU exposure. Double labeling of mitoses and FMRF-amide revealed a close spatial relationship of mesodermal neoblasts with the nervous system. Immunogold-labeled sections showed that nearly 70% of S-phase cells were in direct contact or within 5 μm from nerve cords.


Stem cells BrdU Immunogold Electron microscopy Planarian Macrostomum lignano (Platyhelminthes) 



We thank Gunde Rieger and Robert Gschwentner for rewarding discussions.


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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • A. Bode
    • 1
  • W. Salvenmoser
    • 1
  • K. Nimeth
    • 1
  • M. Mahlknecht
    • 1
  • Z. Adamski
    • 2
    • 3
  • R. M. Rieger
    • 1
  • R. Peter
    • 4
  • P. Ladurner
    • 1
  1. 1.Institute of Zoology and LimnologyUniversity of InnsbruckInnsbruckAustria
  2. 2.Faculty of Biology, Institute of Experimental Biology, Electron Microscope LaboratoryAdam Mickiewicz UniversityPoznañPoland
  3. 3.Faculty of Biology, Institute of Experimental Biology, Department of Animal PhysiologyAdam Mickiewicz UniversityPoznañPoland
  4. 4.Department of Cell BiologyUniversity of SalzburgSalzburgAustria

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