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Spinning and Applications of Spider Silk
Frontiers in Science , 2012, DOI: 10.5923/j.fs.20120205.02
Abstract: Spider silk is specially produced from the different species (sp.) of spider throughout the globe, specially the most fine and mechanically sound silk produced from nephila sp. The fibriller parallel model of spider silk gives higher mechanical properties with better Young’s modulus and lower stress than normal silk coming from the silk-moth. In this review work we dicuss about the collection, composition, spinning and molecular structure, mechanical properties with its application of the spider silk.
Molecular spring: from spider silk to silkworm silk  [PDF]
Xiang Wu,Xiang-Yang Liu,Ning Du,Gang-Qin Xu,Bao-Wen Li
Physics , 2009,
Abstract: In this letter, we adopt a new approach combining theoretical modeling with silk stretching measurements to explore the mystery of the structures between silkworm and spider silks, leading to the differences in mechanical response against stretching. Hereby the typical stress-strain profiles are reproduced by implementing the newly discovered and verified "$\beta$-sheet splitting" mechanism, which primarily varies the secondary structure of protein macromolecules; our modeling and simulation results show good accordance with the experimental measurements. Hence, it can be concluded that the post-yielding mechanical behaviors of both kinds of silks are resulted from the splitting of crystallines while the high extensibility of spider dragline is attributed to the tiny $\beta$-sheets solely existed in spider silk fibrils. This research reveals for the first time the structural factors leading to the significant difference between spider and silkworm silks in mechanical response to the stretching force. Additionally, the combination of theoretical modeling with experiments opens up a completely new approach in resolving conformation of various biomacromolecules.
Hierarchical Chain Model of Spider Capture Silk Elasticity  [PDF]
Haijun Zhou,Yang Zhang
Quantitative Biology , 2004, DOI: 10.1103/PhysRevLett.94.028104
Abstract: Spider capture silk is a biomaterial with both high strength and high elasticity, but the structural design principle underlying these remarkable properties is still unknown. It was revealed recently by atomic force microscopy that, an exponential force--extension relationship holds both for capture silk mesostructures and for intact capture silk fibers [N. Becker et al., Nature Materials 2, 278 (2003)]. In this Letter a simple hierarchical chain model was proposed to understand and reproduce this striking observation. In the hierarchical chain model, a polymer is composed of many structural motifs which organize into structural modules and supra-modules in a hierarchical manner. Each module in this hierarchy has its own characteristic force. The repetitive patterns in the amino acid sequence of the major flagelliform protein of spider capture silk is in support of this model.
Plasticity in Major Ampullate Silk Production in Relation to Spider Phylogeny and Ecology  [PDF]
Cecilia Boutry, Milan ?ezá?, Todd Alan Blackledge
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0022467
Abstract: Spider major ampullate silk is a high-performance biomaterial that has received much attention. However, most studies ignore plasticity in silk properties. A better understanding of silk plasticity could clarify the relative importance of chemical composition versus processing of silk dope for silk properties. It could also provide insight into how control of silk properties relates to spider ecology and silk uses. We compared silk plasticity (defined as variation in the properties of silk spun by a spider under different conditions) between three spider clades in relation to their anatomy and silk biochemistry. We found that silk plasticity exists in RTA clade and orbicularian spiders, two clades that differ in their silk biochemistry. Orbiculariae seem less dependent on external spinning conditions. They probably use a valve in their spinning duct to control friction forces and speed during spinning. Our results suggest that plasticity results from different processing of the silk dope in the spinning duct. Orbicularian spiders seem to display better control of silk properties, perhaps in relation to their more complex spinning duct valve.
Untangling spider silk evolution with spidroin terminal domains
Jessica E Garb, Nadia A Ayoub, Cheryl Y Hayashi
BMC Evolutionary Biology , 2010, DOI: 10.1186/1471-2148-10-243
Abstract: We report 11 additional spidroin N-termini found by sequencing ~1,900 silk gland cDNAs from nine spider species that shared a common ancestor > 240 million years ago. In contrast to their hyper-variable repetitive regions, spidroin N-terminal domains have retained striking similarities in sequence identity, predicted secondary structure, and hydrophobicity. Through separate and combined phylogenetic analyses of N-terminal domains and their corresponding C-termini, we find that combined analysis produces the most resolved trees and that N-termini contribute more support and less conflict than the C-termini. These analyses show that paralogs largely group by silk gland type, except for the major ampullate spidroins. Moreover, spidroin structural motifs associated with superior tensile strength arose early in the history of this gene family, whereas a motif conferring greater extensibility convergently evolved in two distantly related paralogs.A non-repetitive N-terminal domain appears to be a universal attribute of spidroin proteins, likely retained from the origin of spider silk production. Since this time, spidroin N-termini have maintained several features, consistent with this domain playing a key role in silk assembly. Phylogenetic analyses of the conserved N- and C-terminal domains illustrate dramatic radiation of the spidroin gene family, involving extensive duplications, shifts in expression patterns and extreme diversification of repetitive structural sequences that endow spider silks with an unparalleled range of mechanical properties.There are numerous types of spider silks and each has its own suite of mechanical properties, including exceptional tensile strengths, extensibilities, and toughness [1,2]. This mechanical diversity is associated with the distinct functional demands of the different silk types and largely stems from variation in the molecular composition of the silk proteins [3,4]. An individual spider spins a multitude of silk types, with each
Early Events in the Evolution of Spider Silk Genes  [PDF]
James Starrett, Jessica E. Garb, Amanda Kuelbs, Ugochi O. Azubuike, Cheryl Y. Hayashi
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038084
Abstract: Silk spinning is essential to spider ecology and has had a key role in the expansive diversification of spiders. Silk is composed primarily of proteins called spidroins, which are encoded by a multi-gene family. Spidroins have been studied extensively in the derived clade, Orbiculariae (orb-weavers), from the suborder Araneomorphae (‘true spiders’). Orbicularians produce a suite of different silks, and underlying this repertoire is a history of duplication and spidroin gene divergence. A second class of silk proteins, Egg Case Proteins (ECPs), is known only from the orbicularian species, Lactrodectus hesperus (Western black widow). In L. hesperus, ECPs bond with tubuliform spidroins to form egg case silk fibers. Because most of the phylogenetic diversity of spiders has not been sampled for their silk genes, there is limited understanding of spidroin gene family history and the prevalence of ECPs. Silk genes have not been reported from the suborder Mesothelae (segmented spiders), which diverged from all other spiders >380 million years ago, and sampling from Mygalomorphae (tarantulas, trapdoor spiders) and basal araneomorph lineages is sparse. In comparison to orbicularians, mesotheles and mygalomorphs have a simpler silk biology and thus are hypothesized to have less diversity of silk genes. Here, we present cDNAs synthesized from the silk glands of six mygalomorph species, a mesothele, and a non-orbicularian araneomorph, and uncover a surprisingly rich silk gene diversity. In particular, we find ECP homologs in the mesothele, suggesting that ECPs were present in the common ancestor of extant spiders, and originally were not specialized to complex with tubuliform spidroins. Furthermore, gene-tree/species-tree reconciliation analysis reveals that numerous spidroin gene duplications occurred after the split between Mesothelae and Opisthothelae (Mygalomorphae plus Araneomorphae). We use the spidroin gene tree to reconstruct the evolution of amino acid compositions of spidroins that perform different ecological functions.
Antheraea pernyi Silk Fiber: A Potential Resource for Artificially Biospinning Spider Dragline Silk
Yaopeng Zhang,Hongxia Yang,Huili Shao,Xuechao Hu
Journal of Biomedicine and Biotechnology , 2010, DOI: 10.1155/2010/683962
Abstract: The outstanding properties of spider dragline silk are likely to be determined by a combination of the primary sequences and the secondary structure of the silk proteins. Antheraea pernyi silk has more similar sequences to spider dragline silk than the silk from its domestic counterpart, Bombyx mori. This makes it much potential as a resource for biospinning spider dragline silk. This paper further verified its possibility as the resource from the mechanical properties and the structures of the A. pernyi silks prepared by forcible reeling. It is surprising that the stress-strain curves of the A. pernyi fibers show similar sigmoidal shape to those of spider dragline silk. Under a controlled reeling speed of 95 mm/s, the breaking energy was 1.04×105 J/kg, the tensile strength was 639 MPa and the initial modulus was 9.9 GPa. It should be noted that this breaking energy of the A. pernyi silk approaches that of spider dragline silk. The tensile properties, the optical orientation and the -sheet structure contents of the silk fibers are remarkably increased by raising the spinning speeds up to 95 mm/s.
Study of Spider Silk Fibers by Raman Microscopy  [PDF]
Maria Fernanda Vargas-Charry, Carlos Vargas-Hernández
American Journal of Analytical Chemistry (AJAC) , 2018, DOI: 10.4236/ajac.2018.910039
Abstract: Spider silk fibers of species of the genera Araneus, Gasteracantha, and Linothele sericata were studied. The fibers are composed of axial threads and lateral villi, allowing adhesion to surfaces. Raman spectroscopy was used to determine the surface and internal composition of the threads forming the structure. In the three species, the characteristic amino acid peaks of the spider web were found between 2871 and 2975 cm-1, which belong to L-glycine, L-alanine, L-glutamine, and L-proline. The threads are composed of a protective layer mainly composed of amides, alanine, and glycine. The fibrils surrounding the axial fibers consist mainly of amide II (1533 cm-1), which allows adhesion between the thread and the surfaces onto which the spider weaves the web. For the genus Linothele sericata, there is a peak on the surface of this spider web located at 2145 cm-1, which is associated with isonitriles with R-N-C bonds.
Evidence for antimicrobial activity associated with common house spider silk
Simon Wright, Sara L Goodacre
BMC Research Notes , 2012, DOI: 10.1186/1756-0500-5-326
Abstract: In this study we compared the growth of a Gram positive and a Gram negative bacterium in the presence and absence of silk produced by the common house spider Tegenaria domestica. We demonstrate that native web silk of Tegenaria domestica can inhibit the growth of the Gram positive bacterium, Bacillus subtilis. No significant inhibition of growth was detected against the Gram negative bacterium, Escherichia coli. The antimicrobial effect against B. subtilis appears to be short lived thus the active agent potentially acts in a bacteriostatic rather than bactericidal manner. Treatment of the silk with Proteinase K appears to reduce the ability to inhibit bacterial growth. This is consistent with the active agent including a protein element that is denatured or cleaved by treatment. Tegenaria silk does not appear to inhibit the growth of mammalian cells in vitro thus there is the potential for therapeutic applications.Spiders use silk for a variety of different purposes such as web spinning, cocoon construction and as substrates upon which to deposit sperm. Silks vary in their mechanical properties such as in the degree of extensibility and maximum strength [1][2]. The range of physical properties observed likely reflects differences amongst silk types in the relative proportions and combinations of particular amino acids such as alanine, glycine and proline [3].Spider silks can be grouped into five basic categories: dragline (also known as major ampullate), capture spiral, tubiliform, aciniform and minor-ampullate silks, each of which is used for a different purpose. In this study we examined the properties of combined samples of dragline and capture spiral silk from the agelenid spider Tegenaria domestica (Clerk 1757). This spider weaves funnel webs and is commonly found in leaf detritus or underneath rocks [4]. It uses dragline silk for creating the web’s outer rim and spokes, and also for the lifeline that attaches the spider to a surface. Capture spiral silk is use
Interactions between Spider Silk and Cells – NIH/3T3 Fibroblasts Seeded on Miniature Weaving Frames  [PDF]
Joern W. Kuhbier,Christina Allmeling,Kerstin Reimers,Anja Hillmer,Cornelia Kasper,Bjoern Menger,Gudrun Brandes,Merlin Guggenheim,Peter M. Vogt
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0012032
Abstract: Several materials have been used for tissue engineering purposes, since the ideal matrix depends on the desired tissue. Silk biomaterials have come to focus due to their great mechanical properties. As untreated silkworm silk has been found to be quite immunogenic, an alternative could be spider silk. Not only does it own unique mechanical properties, its biocompatibility has been shown already in vivo. In our study, we used native spider dragline silk which is known as the strongest fibre in nature.
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