1062-3604/04/3504- © 2004
Russian Journal of Developmental Biology, Vol. 35, No. 4, 2004, pp. 228–232. Translated from Ontogenez, Vol. 35, No. 4, 2004, pp. 285–290.
Original Russian Text Copyright © 2004 by Sheiman, Kreshchenko, Sedel’nikov, Groznyi.
Regeneration is keeping many riddles. Planarians
are a time-tested object for studies of regeneration
because of its great morphogenetic plasticity. Some
planarians that reproduce asexually are capable of both
natural (after ﬁssion) and artiﬁcial (induced) regenera-
tion. Some patterns of regeneration were described in
the beginning of the 20th century (Morgan, 1901;
Studies of restorative morphogenesis in ﬁssioning
planarians can further understanding of regeneration
induced by body injuries. We have undertaken a com-
parative analysis of regeneration after ﬁssion of planar-
ians and after transections at different body levels.
Studies were carried out at the initial stage of regenera-
tion: blastema formation and growth.
MATERIALS AND METHODS
Studies were carried out on the laboratory
race of planarians
at the Institute of Cell Biophysics, Russian Academy of
Sciences, for tens of years under constant conditions.
Water is changed in the aquaria twice a year and tem-
perature is maintained at 19–21
C. Planarians are fed
on earthworms and chironomid larvae. Racks with jars
containing planarians are shielded by dark cloth. For
experiments, planarians, 12–13 mm long, with sharp
tail end were selected.
Transections were performed under a
dissection microscope using an ophthalmic scalpel.
Planarians on ﬁlter paper were placed on ice-cold sur-
face in Petri dishes for partial immobilization. After
transection, various body parts were formed which
were designated as fragments: anterior (
, and posterior (
on the site of transection. The blastemas from which the
anterior end was formed were designated as head blast-
emas, while those from which the posterior end was
formed were designated as tail blastemas. Fissioned
planarians were picked up in the morning after night
The blastema growth was studied
using morphometry. A device was designed and tech-
nique was developed for image analysis, which allows
measurement of the blastema area in planarians. There
were certain difﬁculties in choosing the camcorder.
First, planarians poorly contrast with the background in
water and, second, they respond to sharp changes in
illumination. A WAT-502A camcorder (Watec, Japan)
was selected, which could work at a low level of illumi-
nation and was characterized by a high sensitivity. It is
equipped with a screw thread allowing attachment of a
special adapter for mounting onto the dissection micro-
scope ocular. Another difﬁculty is related to the mobil-
ity of planarians. Since it is impossible to ﬁx the object,
it is necessary to choose a moment for ﬁlming. An Aver
Media TV Capture 98 with VCR was used for input of
images from the camcorder, which allows a stop-frame.
At the required position of a planarian, a stop-frame is
made and if the resulting image is satisfactory, it is
input in the computer. The software NIH Image on a
Pentium II Celeron (USA) was used as a program capa-
ble of isolating the object and measuring its length and
Blastema was isolated on images of regenerating
planarians and its area was expressed in arbitrary units
= 1266 arb. units).
Measurements were performed for ﬁve days of
regeneration starting from day 3 after the operation.
Ten to 30 animals were examined in each group of
Morphogenesis in Planarians
I. M. Sheiman*, N. D. Kreshchenko*, Z. V. Sedel’nikov**, and A. V. Groznyi*
* Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290 Russia
** Pushchino State University, Pushchino, Moscow oblast, 142290 Russia
Received May 21, 2003; in ﬁnal form, February 3, 2004
—We carried out computer morphometry in regenerates of planarians
. The blastema
growth was analyzed in fragments of planarians after their ﬁssion and after transverse transection at different
body levels. The blastema was growing at a higher rate on tail fragments than on the head fragments and the
growth rate was the higher, the closer the transection was to the head end. After ﬁssion, the blastema was grow-
ing at a slower rate than after transection in the ﬁssion zone. The growth of adjacent blastemas formed on both
sides after ﬁssion or transection proceeded at different rates as a function of new body polarity.
: planarians, ﬁssion, regeneration, morphogenesis, morphometry.