ISSN 10623604, Russian Journal of Developmental Biology, 2012, Vol. 43, No. 1, pp. 1–11. © Pleiades Publishing, Inc., 2012.
Original Russian Text © E.S. Pshennikova, A.S. Voronina, 2012, published in Ontogenez, 2012, Vol. 43, No. 1, pp. 3
In the utmost point of the rostral area of a larvae of
most batrachians, there is a small, slightly raised, and
very daub isle of cells called the cement gland—an
adhesive organ that is also termed cupule, although it
would be more correct to call it sticker (Nieuwkoop
and Faber, 1967; Ryder, 1888; reviews by Sive and Bra
dley, 1996; Pennati et al., 2000). Cells of the cement
gland extract waterproof mucus which allows the
hatched embryo to attach to a solid support until it is
able to swim and feed well. There are data that the
embryo’s cement gland is fixed to the internal surface
of the vitellin sheath even before hatching. In the point
of action of the enzyme produced by the hatching
gland (it is located in the front of the embryo above the
cement gland and has an inversed Vform), the vitellin
sheath breaks and the embryo is driven from it by the
fluid head but remains fixed on it (Bles, 1905—cited
from Nochbatolfoghahai and Downie, 2005).
The cement glands have been discovered in
embryos of other chordates, i.e., single ascidia and
some bony fishes such as cichlids (Sive and Bradley,
1996). In some urodelous amphibians, the temporal
adhesion organ—balancers—exists (Harrison, 1925).
Both stickers and balancers produce mucus, have sim
ilar innervation, and are likely to be evolutionally close
(SaukaSpengler et al., 2002). However, their histo
logical structure is not clearly similar (Nokhbatol
foghahai and Downie, 2005).
The review by Desnitskii (2004) is devoted to the
study of ontogenesis of batrachians with direct devel
opment and marsupial frogs and the batrachians’
. It is quite natural that
cement glands are not found in species whose embryo
development does not involve coming into open water
reservoirs (Nokhbatolfoghahai and Downie, 2005).
Thus, tadpoles of the
hatch at a later stage than those of
are able to swim and feed. Tree frog
does not have a tadpole stage at all, and the
young frog pips from a large egg. The third amphibian
species in which the authors have not found the
cement gland (
) is biologically
very close to the species having this organ. This
appeared to be unexpected but quite explainable:
before coming to the water, the hatched tadpole enters
the state of socalled “development arrest” which
spans until heavy rain, and for this time, the tadpole
becomes ready for life in the water reservoir.
In batrachians, the cement gland is seen first as a
pigmented plain strip of cells located a bit more ven
trally than the frontmost end of the embryo. Further,
it remains in the same location only in embryos of
. In other species, it acquires a V or
Mshaped form or is divided into two parts, as in
(Nokhbatolfoghahai and Downie, 2005).
The same paper cites the results of scrupulous micro
scopic studies in the cement glands of 20 species of
batrachians belonging to six families and makes an
attempt to morphologically classify these structures.
Five types of development of the cement gland in these
animals’ embryos are described in detail, and compar
ison of the data obtained with the literature data of
other authors is given.
The cement gland has its own innervation with the
lowerjaw branch of the trifacial, resulting in inhibi
tory response, which prevents the attached embryo’s
movements. This is energysaving, and the embryo
becomes less visible (Roberts and Blight, 1975; Davies
et al., 1982; Boothby and Roberts, 1992a and b).
Attachment of the tadpole with the help of the
cement gland is a complex physiological process
(Lambert et al., 2004). In the resting state, mucus tears
Cement Gland as the Adhesion Organ in
E. S. Pshennikova and A. S. Voronina
Bakh Institute of Biochemistry, Russian Academy of Sciences, Leninskii pr. 33, Moscow, 119071 Russia
Received April 5, 2010; in final form, December 23, 2010
—The cement gland in batrachians is a temporal ectodermic organ which is necessary for an
embryo’s attachment to the substrate. In this review, some notions about the origin of the cement gland of
frogs, its functioning, genes being expressed in it, and regulation of its formation and develop
ment are provided. The role of some homologies of
genes of the cement gland in
at different conditions of other animals and man.
, cement gland, embryonic induction, regulation of gene expression.