Supernumerary limb induction in the anura

Abstract

Supernumerary Limb Induction in t h e A n u r a B. 1. BALINSKY D e p u r t m e n t of Zoology, Llniucrsity of the Witzutrtcrsrtr 1 1~1 , Johrlizn rsburg ABSTRACTInduction of supcrnumcrary limbs in Bufo tadpoles was achieved by transplanting the transverse rieural fold with adjoining tissue €rom neurulae into tail bud stage embryos. The graft differentiatcd into brain, eyes, noses and mouthparts. Induced limb rudiments were associatcd with either noses or mouthparts. l'he author rejects the suggestion made by Perri that the induction is due to release of products of cytoolysis froin the graft and suggests that limb induction is due to a disorganization or reduction of the subepidermal basement imcmbrane (layer of collagen fibres) by certain grafts, and that as a result the potentially limb forming flank mesenchyme is allowed to interact with the epidermis -a precondition for limb development. In support of this view the author prvscnts clectronmicrographs in which it is shown that at the edge of the nostril, arid on the mouthparts (lips, oral papillae), the basal membrane is attenuated and disorganised, allowing processes of mesenchyme cells to penetrate through the layer of collagen fibres and reach the inner surface 01 the epidermis.

Developmental origin of the clavicle, and its implications for the evolution of the neck and the paired appendages in vertebrates

“…). Even in late developmental stages, the application of certain tissues or substances can induce supernumerary limb initiation in the interlimb region in various osteichthyan species (Balinsky, ; Hornbruch & Wolpert, ; Cohn et al. ; Ohuchi et al.…”

“…Actually, in early-stage chicken embryos, the neck and interlimb levels of the LPM with its associated ectoderm, endoderm, somites and intermediate mesoderm were reported to be able to differentiate into limbs when they were implanted into the body cavity (Stephens et al 1989). Even in late developmental stages, the application of certain tissues or substances can induce supernumerary limb initiation in the interlimb region in various osteichthyan species (Balinsky, 1974;Hornbruch & Wolpert, 1991;Cohn et al 1995;Ohuchi et al 1995;Abud et al 1996;Tanaka et al 2000;Yonei-Tamura et al 2008). Because gene expressions in chondrichthyes imply the presence of a limbforming field in the lateral flank as well, the appendageforming competence is assumed to have allowed various rostrocaudal positions of paired appendages in early gnathostomes (Yonei-Tamura et al 2008).…”

Competent stripes for diverse positions of limbs/fins in gnathostome embryos

“…The competent stripe also remains at the lateral region. Results of some studies—including those for the zebrafish presented here—indicate that several kinds of artificial manipulation can stimulate the flank region to induce additional AER and limb/fin buds (Balinsky 1974; Cohn et al 1995; Tanaka et al 2000). The use of the lateral stripe differs greatly among gnathostomes and each species has different ratios for the forelimb/pectoral fin, flank, and hindlimb/pelvic fin.…”

“…Generally, gnathostomes possess two pairs of lateral appendages separated by the flank, or diastema, between the appendages. Similarly to the dorsal stripe, the flank is also known to be competent for AER induction, at least in tetrapods (amphibians, Balinsky 1974 and references therein; chicken, Cohn et al 1995; mouse, Tanaka et al 2000). We examined the lateral competence in teleost fish.…”

Introduction of Boris Balinsky to Embryology

“…When back in the Republic of South Africa, he carried out a detailed study of limb development in amphibians using this method. One of his papers based on the use of electron microscopy (Balinsky, 1974b) was recognized by Current Contents as one of the most frequently cited papers. In this paper, Balinsky repeated his experiment of the 1920s and demonstrated that, like during normal development, the formation of ectopic limbs is related to the absence of basal membrane in the limb rudiment.…”