Structure - Property and Structure - Function Relations of Leafhopper (Kahaono montana) Silk

Abstract

Kahaono montana Evans (Insecta: Hemiptera: Cicadellidae), an endemic Australian leafhopper, is unique among the insect order Hemiptera in producing a silk. In this study, the secondary structure of the protein comprising leafhopper silk, and the surface stretching mechanical properties of this biopolymer, were investigated using Fourier-transform infrared microscopy and atomic force microscopy, respectively. The curve-fitted amide I and amide III bands revealed a composition of 13.1% α-helix, 23.8% β-sheet, 25.5% random coil, and 37.6% aggregated side chains. The molecular stretching behaviour of raw and cleaned silk fibres differed markedly. Analysis of the AFM force curves showed an adhesive property of the raw silk, while the pure fibre showed only the presence of protein. These findings suggest that the silk fibres act as a structural support for other leafhopper secretions and together form a hydrophobic barrier that may protect the insects from rain and natural enemies. This is the first time such a use of silk has been found in a biological system.

Comparison of Embiopteran Silks Reveals Tensile and Structural Similarities across Taxa

“…In particular, the amide I and amide III regions of the FTIR spectrograms are often used for protein structural studies. 23,40,46 Although weaker in intensity than amide I, spectral bands in amide III are more resolved, which aids in band assignment. 47 This difference in resolution can be seen with the embiopteran silks.…”

Electrospinning of silk fibroin and collagen for vascular tissue engineering

“…As shown in Fig. 6, strong peaks at 1621 cm −1 , 1517 cm −1 and 1230 cm −1 appeared, indicative of the characteristic peaks of ␤-sheets [22,27]. Compared with the scaffolds that were untreated, the amide peaks moved from may suggest the reaction between SF and collagen.…”

“…FTIR is based on the absorption differences in vibration of the amide bonds, including ␣-helix, ␤-sheet, turns, random coil, and aggregated strands. Three major spectral regions identified in a protein spectrum, amides I, II, and III, contain various vibration bands corresponding to each individual conformation [22,23]. The reported peaks of the ␤-sheet conformation appear at 1616-1637 cm −1 (amide I), 1515-1525 cm −1 (amide II) and 1265 cm −1 (amide III), while the typical peaks of the random coil/␣-helix are at 1638-1660 cm −1 (amide I), 1540-1545 cm −1 (amide II) and 1235 cm −1 (amide III) [16,[24][25][26].…”

Corymbia leaf oils, latitude, hybrids and herbivory: A test using common‐garden field trials

“…Kahaono montana Evans (Hemiptera: Cicadellidae) is unique within the Hemiptera in its production of silken shelters (Chang et al 2006;Sutherland et al 2010), and has previously been recorded from three eucalypt species (Fletcher & Kent 2002;M. Fletcher pers.…”