Nanostructural and mechanical property changes to spider silk as a consequence of insecticide exposure

Benamú, Marco Antonio; Lacava, Mariángeles; García, Luis Fernando; Santana, M. de F. S. de; Fang, J.; Wang, Xungai; Blamires, Sean J.

doi:10.1016/j.chemosphere.2017.04.079

Cited by 25 publications

(16 citation statements)

References 58 publications

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“…Accordingly, 48 frames were collected per treatment per species, i.e. 6 frames x 8 individual threads (see [ 26 , 52 ] for details).…”

Section: Methodsmentioning

confidence: 99%

“…We collected silk from a further three individuals per treatment per species for SAXS/WAXS analyses. We did this by spooling their silk onto 3 mm x 1 mm titanium frames containing 0.5 mm x 0.5 mm windows (see [ 52 ]) for ~1 h ( A . keyserlingi , L .…”

Section: Methodsmentioning

confidence: 99%

“…We collected between 1000–2000 rounds of silk across the windows of each frame. We have previously found this amount of silk to be adequate for attaining quality scattering from 5-35keV synchrotron X-ray sources [ 25 , 27 , 52 ].…”

Section: Methodsmentioning

confidence: 99%

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Multiscale mechanisms of nutritionally induced property variation in spider silks

et al. 2018

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Variability in spider major ampullate (MA) silk properties at different scales has proven difficult to determine and remains an obstacle to the development of synthetic fibers mimicking MA silk performance. A multitude of techniques may be used to measure multiscale aspects of silk properties. Here we fed five species of Araneoid spider solutions that either contained protein or were protein deprived and performed silk tensile tests, small and wide-angle X-ray scattering (SAXS/WAXS), amino acid composition analyses, and silk gene expression analyses, to resolve persistent questions about how nutrient deprivation induces variations in MA silk mechanical properties across scales. Our analyses found that the properties of each spider’s silk varied differently in response to variations in their protein intake. We found changes in the crystalline and non-crystalline nanostructures to play specific roles in inducing the property variations we found. Across treatment MaSp expression patterns differed in each of the five species. We found that in most species MaSp expression and amino acid composition variations did not conform with our predictions based on a traditional MaSp expression model. In general, changes to the silk’s alanine and proline compositions influenced the alignment of the proteins within the silk’s amorphous region, which influenced silk extensibility and toughness. Variations in structural alignment in the crystalline and non-crystalline regions influenced ultimate strength independent of genetic expression. Our study provides the deepest insights thus far into the mechanisms of how MA silk properties vary from gene expression to nanostructure formations to fiber mechanics. Such knowledge is imperative for promoting the production of synthetic silk fibers.

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“…Accordingly, 48 frames were collected per treatment per species, i.e. 6 frames x 8 individual threads (see [ 26 , 52 ] for details).…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Multiscale mechanisms of nutritionally induced property variation in spider silks

et al. 2018

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“…First, to collect the silk for both spectrophotometry and WAXS a single MA silk thread was pulled across 3 mm × 1 mm titanium frames containing 0.5 mm × 0.5 mm windows. We then spooled the silk for 1 h, which resulted in approximately 1000 rounds being collected across the frame windows (see Benamú et al [51] for details). Second, the silk was wrapped around a glass tube connected to the rotating spool for another 1 h. This resulted in approximately 15 mg of thread being wound onto the glass tube.…”

Section: Silk Collectionmentioning

confidence: 99%

“…These parameters allowed us to thereupon calculate: (i) d-spacing (or relative distances between pleated β-sheet) among the crystalline structures, (ii) relative crystalline intensity ratios (I 020 /I amorphous and I 210 /I amorphous ) with I 020 , I 210 and I amorphous , representing the sum of the scattering intensity at the (0 2 0) and (2 1 0) Bragg reflections and the amorphous halo, respectively, (iii) crystallinity index (X c ), representing an estimate of size of β-sheet crystallites and (iv) Herman's orientation function ( f c ). Details pertaining to the application, analytical procedures and equations used in the WAXS analyses are found elsewhere [41,49,51].…”

Section: Wide-angle X-ray Diffraction Analysismentioning

confidence: 99%

Spider silk colour covaries with thermal properties but not protein structure

Blamires

Cerexhe

White

et al. 2019

J. R. Soc. Interface.

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Understanding how and why animal secretions vary in property has important biomimetic implications as desirable properties might covary. Spider major ampullate (MA) silk, for instance, is a secretion earmarked for biomimetic applications, but many of its properties vary among and between species across environments. Here, we tested the hypothesis that MA silk colour, protein structure and thermal properties covary when protein uptake is manipulated in the spider Trichonephila plumipes . We collected silk from adult female spiders maintained on a protein-fed or protein-deprived diet. Based on spectrophotometric quantifications, we classified half the silks as ‘bee visible’ and the other half ‘bee invisible’. Wide angle X-ray diffraction and differential scanning calorimetry were then used to assess the silk's protein structure and thermal properties, respectively. We found that although protein structures and thermal properties varied across our treatments only the thermal properties covaried with colour. This ultimately suggests that protein structure alone is not responsible for MA silk thermal properties, nor does it affect silk colours. We speculate that similar ecological factors act on silk colour and thermal properties, which should be uncovered to inform biomimetic programmes.

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