The evolution of venom-conducting fangs: Insights from developmental biology

Jackson, Kate

doi:10.1016/j.toxicon.2007.01.007

Cited by 54 publications

(43 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As has been previously reported by SEMs, mineralization occurs from tip to base, with the discharge orifice emerging already formed as the mineralised layer is laid down (Fig. 1E) (Jackson, 2002(Jackson, , 2007. In sections, it is clear that the venom-conducting canal does not sit freely within the fang papilla, but is found towards the ventral side of the fang, anchored to the outer layer by a line of dentine (Fig 2A and B).…”

Section: The Morphology Of the Fully Formed Fangsupporting

confidence: 73%

See 1 more Smart Citation

Viperous fangs: Development and evolution of the venom canal

Zahradnicek

Horáček

Tucker

2008

Mechanisms of Development

View full text Add to dashboard Cite

Fangs are specialised long teeth that contain either a superficial groove (Gila monster, Beaded lizard, some colubrid snakes), along which the venom runs, or an enclosed canal (viperid, elapid and atractaspid), down which the venom flows inside the tooth. The fangs of viperid snakes are the most effective venom-delivery structures among vertebrates and have been the focus of scientific interests for more than 200 years. Despite this interest the questions of how the canal at the centre of the fang forms remains unresolved. Two different hypotheses have been suggested. The mainstream hypothesis claims that the venom-conducting canal develops by the invagination of the epithelial wall of the developing tooth germ. The sides of this invagination make contact and finally fuse to form the enclosed canal. The second hypothesis, known as the "brick chimney", claims the venom-conducting canal develops directly by successive dentine deposition as the tooth develops. The fang is thus built up from the tip to the base, without any folding of the tooth surface. In an attempt to cast further light on this subject the early development of the fangs was followed in a pit viper, Trimeresurus albolabris, using the expression of Sonic hedgehog (Shh). We demonstrate that the canal is indeed formed by an early folding event, resulting from an invagination of epithelial cells into the dental mesenchyme. The epithelial cells proliferate to enlarge the canal and then the cells die by apoptosis, forming an empty tube through which the poison runs. The entrance and discharge orifices at either end of the canal develop by a similar invagination but the initial width of the invagination is very different from that in the middle of the tooth, and is associated with higher proliferation. The two sides of the invaginating epithelium never come into contact, leaving the orifice open. The mechanism by which the orifices form can be likened to that observed in reptiles with an open groove along their fangs, such as the boomslang. It is thus tempting to speculate that the process of orifice formation in viperids represents the ancestral pleisomorphic state, and that enclosed canals developed by a change in the shape and size of the initial invagination.

show abstract

Section: The Morphology Of the Fully Formed Fangsupporting

confidence: 73%

“…In viperids, the surface of the fang on the anterior side, in between the entrance and discharge orifice, is smooth. In contrast, in elapids and atractaspids an anterior suture line connects the two orifices, although the venom canal is still enclosed (Bogert, 1943;Kochva and Meier, 1986;Jackson, 2002Jackson, , 2007.…”

Section: Introductionmentioning

confidence: 99%

Viperous fangs: Development and evolution of the venom canal

Zahradnicek

Horáček

Tucker

2008

Mechanisms of Development

View full text Add to dashboard Cite

show abstract

“…[15] The mechanical properties, microstructure and chemical composition of the teeth of extant reptiles is still a poorly studied area, with some investigations being focussed on the microstructure and chemical composition [11,12,16] and others concentrated on the evolution, surface features and modifications associated with venom delivery through fangs. [6,[17][18][19][20][21] However, exploration of the mechanical properties and mechanisms in relation to the compositional characteristics are essential factors in understanding natural composites [9] as found in teeth and fangs.…”

Section: Introductionmentioning

confidence: 99%

Chemical and mechanical properties of snake fangs

Vuuren

Dickenson

Gordon

et al. 2016

J Raman Spectroscopy

View full text Add to dashboard Cite

The composition of dental tissues and their interaction determines its mechanical properties. The mechanical properties and chemical composition of the teeth of extant reptiles are still poorly studied areas. As a preliminary study the fangs of four species of snakes and a human tooth were investigated through nanoindentation and Raman spectroscopy. The average elastic modulus values for the main body of the fangs ranged from 15.3 GPa to 24.6 GPa, and 19.1 GPa for the human dentine. Raman spectroscopy and principal component analysis (PCA) showed that snake fangs are similar in composition to human dentine, both of which comprised of hydroxyapatite and an organic matrix. The elastic modulus and hardness data were correlated to the Raman spectra using partial least squares regression (PLS). The spectral features which correlated with the elastic modulus would suggest that elastic modulus is dependent on the relative protein to mineral amounts in the tooth. The form of the phosphate and the relative levels of phosphate to organic components also appear to be governing factors for elastic modulus. The PLS of Raman spectra against the hardness gave very similar results. The small differences between snake fangs and human dentine appeared to be because of carbonate content, with higher levels of carbonate in the human tooth than the snake fangs.Snake fangs should be able to withstand large lateral forces. Human dentine aids in dissipating imposed loads. This similarity in the chemical composition of the snake fangs and human dentine supported the findings of the similarities in mechanical properties, which may be attributed to the similar functional demands of these biocomposites.

show abstract

“…Possuem um aparelho inoculador solenóglifo (as maxilas possuem apenas um par de dentes funcional agudo e oco) (MELGAREJO et al, 2003). Em associação ao aparato inoculador, estão presentes as glândulas de peçonha na região pós-orbital e, quando comprimidas por músculos acessórios, secretam seu conteúdo (JACKSON, 2007;FRY et al, 2008;VONK et al, 2008). A subfamília Crotalinae, incluída na família Viperidae, apresenta um par de fosseta loreal, um órgão que é termorreceptor e se encontra localizado entre a narina e o olho da serpente.…”

Section: Serpentes Do Brasilunclassified

Caracterização estrutural e funcional de um fator de crescimento endotelial vascular, VEGF, da peçonha da serpente Crotalus durissus collilineatus

Ferreira¹

View full text Add to dashboard Cite

The evolution of venom-conducting fangs: Insights from developmental biology

Cited by 54 publications

References 15 publications

Viperous fangs: Development and evolution of the venom canal

Viperous fangs: Development and evolution of the venom canal

Chemical and mechanical properties of snake fangs

Caracterização estrutural e funcional de um fator de crescimento endotelial vascular, VEGF, da peçonha da serpente Crotalus durissus collilineatus

Contact Info

Product

Resources

About