Structure and properties of silk from the African wild silkmoth Gonometa postica reared indoors.
Bottom Line: The cocoons reared indoors showed inferior quality in weight, length, width, and cocoon shell ratio compared to cocoons reared outdoors.Indoor-reared cocoon shells had a significantly higher breaking strain, while the breaking stress was higher for cocoons reared outdoors.Fibers from indoor cocoons had a significantly higher breaking stress while outdoor fibers had higher breaking strain.
Affiliation: International Centre for Insect Physiology and Ecology, P.O. Box, 30772-00100, Nairobi, Kenya email@example.com.Show MeSH
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Mentions: Figure 1 shows the surface and cross sections of silk cocoon shells and degummed fibers of G. postica reared indoors and outdoors. There was no clear difference in the surface structures and cross sectional shapes of degummed fibers from cocoons reared indoors and outdoors (Figure 1A–D). There were some artifacts of the degumming process and the spinning behavior, causing inconsistency in the diameter along the fiber axis. The average diameter of the fibers was smaller (16 µm) in indoor cocoons compared to outdoor cocoons (21 µm). The fibers had regular and unfractured surfaces with globular to triangular cross sections (Figure 1C, D). The surfaces of both cocoon shells were rough, covered with randomly arranged fibers, and showed countless cross bindings, wrinkles, and networking of twisted filaments (Figure 1E, F). The cocoons were multilayered and porous, with high sericin/gum content. Cocoon thickness was 0.536 mm for outdoor cocoons, which was considerably higher than indoor cocoons (0.326 mm). The cocoon shells were covered with crystals, though the crystals on the outdoor cocoons were larger in size than indoor cocoons (Figure 1G, H). The crystal layer was also thinner in indoor cocoon shells (Figure 1I, J). The FTIR spectra showed the peaks (at 1312/cm and 777/cm) were attributed to calcium oxalate monohydrate crystals (Sigma-Aldrich, www.sigmaaldrich.com) (Figure 2).
Affiliation: International Centre for Insect Physiology and Ecology, P.O. Box, 30772-00100, Nairobi, Kenya firstname.lastname@example.org.