Comparative study of eye defective worm 'menashi' and regenerating wild-type in planarian, Dugesia ryukyuensis

Yukiko Sato, Kazuya Kobayashi, Midori Matsumoto, Motonori Hoshi, Sumiko Negishi

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Inbreeding of the sexualized planarian, Dugesia ryukyuensis, produces eye-defective worms, menashi, in the F1 population. To study the effects of this mutation on the eye, we observed the eye-region of menashi using electron microscopy and compared it with the regenerating eye in wild-type worms. The intact eye of wild-type planarians consisted of a few pigment cells and a number of visual cells. Pigment cells containing spherically-shaped electron-dense melanosomes contacted each other and enclosed rhabdomes of visual cells. Rhabdomes had numerous tubular microvilli extending radially and touching the pigment cells. However, in menashi, various lengths of tubular microvilli were irregularly distributed near the pigment cells, which contained numerous electron-lucent premelanosomes, and no adhesive structures were found between the pigment cells. The premelanosomes of menashi were equal in size to those seen after 2 days of regeneration in wild-type planarians and were similar in maturation to those found after 3 days of regeneration in wild-type planarian. These results suggest that menashi is defective in the mechanism(s) of developing pigment granules and constructing visual cells. These findings also suggest that pigment cells in menashi are defective in the mechanism(s) involved with cell adhesion.

Original languageEnglish
Pages (from-to)86-91
Number of pages6
JournalPigment Cell Research
Issue number2
Publication statusPublished - 2005 Apr


  • Eye-defective
  • Ocellus
  • Pigment cell
  • Planarian
  • Regeneration

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science
  • Developmental Biology
  • Clinical Biochemistry
  • Cell Biology


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