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Chitin in the silk gland ducts of the spider Nephila edulis and the silkworm Bombyx mori.

Davies GJ, Knight DP, Vollrath F - PLoS ONE (2013)

Bottom Line: Here we report the detection and localisation of chitin in the cuticle of the spinning ducts of both the spider Nephila edulis and the silkworm Bombyx mori.Our observations demonstrate that the duct walls of both animals contain chitin notwithstanding totally independent evolutionary pathways of the systems.We conclude that chitin may well be an essential component for the construction of spinning ducts; we further conclude that in both species chitin may indicate the evolutionary origin of the spinning ducts.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, The University of Oxford, South Parks Road, Oxford, United Kingdom.

ABSTRACT
Here we report the detection and localisation of chitin in the cuticle of the spinning ducts of both the spider Nephila edulis and the silkworm Bombyx mori. Our observations demonstrate that the duct walls of both animals contain chitin notwithstanding totally independent evolutionary pathways of the systems. We conclude that chitin may well be an essential component for the construction of spinning ducts; we further conclude that in both species chitin may indicate the evolutionary origin of the spinning ducts.

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Chitin location within the spider duct.(A) Tracing of spider duct, showing portion solubilised by acid in yellow and section remaining after KOH treatment and testing positive for chitin highlighted in red. (B) Duct profile of both and early and late spider instars from Figure 2 in Davies, Knight et al. 2013, with valve positioned at x = 0. The symbols (red diamonds early instar; red triangles late instar) are for the part of the duct that stains for chitin and the yellow from the remainder of the duct that is destroyed in the test. This indicates that the surviving region is confined to the section of the duct that narrows linearly in both early and late instar spiders.
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pone-0073225-g003: Chitin location within the spider duct.(A) Tracing of spider duct, showing portion solubilised by acid in yellow and section remaining after KOH treatment and testing positive for chitin highlighted in red. (B) Duct profile of both and early and late spider instars from Figure 2 in Davies, Knight et al. 2013, with valve positioned at x = 0. The symbols (red diamonds early instar; red triangles late instar) are for the part of the duct that stains for chitin and the yellow from the remainder of the duct that is destroyed in the test. This indicates that the surviving region is confined to the section of the duct that narrows linearly in both early and late instar spiders.

Mentions: For each of the spider duct studied, the portion remaining after KOH treatment and staining was found to extend from the tip of the spigot to a point approximately half way along the final limb of the three folded limbs of the duct. This location is shown in Figure 3 (A) in which the portion of duct wall testing positively for chitin is shown superimposed on a traced image of the entire duct.


Chitin in the silk gland ducts of the spider Nephila edulis and the silkworm Bombyx mori.

Davies GJ, Knight DP, Vollrath F - PLoS ONE (2013)

Chitin location within the spider duct.(A) Tracing of spider duct, showing portion solubilised by acid in yellow and section remaining after KOH treatment and testing positive for chitin highlighted in red. (B) Duct profile of both and early and late spider instars from Figure 2 in Davies, Knight et al. 2013, with valve positioned at x = 0. The symbols (red diamonds early instar; red triangles late instar) are for the part of the duct that stains for chitin and the yellow from the remainder of the duct that is destroyed in the test. This indicates that the surviving region is confined to the section of the duct that narrows linearly in both early and late instar spiders.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756001&req=5

pone-0073225-g003: Chitin location within the spider duct.(A) Tracing of spider duct, showing portion solubilised by acid in yellow and section remaining after KOH treatment and testing positive for chitin highlighted in red. (B) Duct profile of both and early and late spider instars from Figure 2 in Davies, Knight et al. 2013, with valve positioned at x = 0. The symbols (red diamonds early instar; red triangles late instar) are for the part of the duct that stains for chitin and the yellow from the remainder of the duct that is destroyed in the test. This indicates that the surviving region is confined to the section of the duct that narrows linearly in both early and late instar spiders.
Mentions: For each of the spider duct studied, the portion remaining after KOH treatment and staining was found to extend from the tip of the spigot to a point approximately half way along the final limb of the three folded limbs of the duct. This location is shown in Figure 3 (A) in which the portion of duct wall testing positively for chitin is shown superimposed on a traced image of the entire duct.

Bottom Line: Here we report the detection and localisation of chitin in the cuticle of the spinning ducts of both the spider Nephila edulis and the silkworm Bombyx mori.Our observations demonstrate that the duct walls of both animals contain chitin notwithstanding totally independent evolutionary pathways of the systems.We conclude that chitin may well be an essential component for the construction of spinning ducts; we further conclude that in both species chitin may indicate the evolutionary origin of the spinning ducts.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, The University of Oxford, South Parks Road, Oxford, United Kingdom.

ABSTRACT
Here we report the detection and localisation of chitin in the cuticle of the spinning ducts of both the spider Nephila edulis and the silkworm Bombyx mori. Our observations demonstrate that the duct walls of both animals contain chitin notwithstanding totally independent evolutionary pathways of the systems. We conclude that chitin may well be an essential component for the construction of spinning ducts; we further conclude that in both species chitin may indicate the evolutionary origin of the spinning ducts.

Show MeSH