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Encyclopedia > Spider silk

Spider silk is a fibre secreted by spiders. Spider silk is a remarkably strong material. Its tensile strength is comparable to that of high-grade steel — according to Nature (see reference below), spider silk has a tensile strength of roughly 1.3 GPa, while one source [1] lists a tensile strength for one form of steel at 1.65 GPa. However, spider silk is much less dense than steel; its ratio of tensile strength to density is perhaps 5 times better than steel — as strong as Aramid filaments, such as Twaron or Kevlar. In fact, a strand of spider silk long enough to circle the earth would weigh less than 16 ounces[citation needed] (less than 460 grams). For the meaning of fiber in nutrition, see dietary fiber. ... Diversity 111 families, 40,000 species Suborders Mesothelae Mygalomorphae Araneomorphae  See table of families Closeup image of a Wolf Spider Wikispecies has information related to: Spiders Spiders are predatory invertebrate animals that have two body segments, eight legs, no chewing mouth parts and no wings. ... Silk weaver Silk is a natural protein fiber, some forms of which can be woven into textiles. ... Tensile strength measures the force required to pull something such as rope, wire, or a structural beam to the point where it breaks. ... Look up steel in Wiktionary, the free dictionary. ... First title page, November 4, 1869 Nature is one of the oldest and most reputable scientific journals, first published on 4 November 1869. ... The gigapascal, symbol GPa is an SI unit of pressure. ... Aramid fiber (1961) is a fire-resistant and strong synthetic fiber. ... Chemical structure of Kevlar. ... Chemical structure of Kevlar. ...

Contents

Usage

A female specimen of Argiope appensa wraps her prey in silk.
A female specimen of Argiope appensa wraps her prey in silk.

Spiders normally use their silk to make structures, either for protection for their offspring, or for predation on other creatures. They can also suspend themselves using their silk, normally for the same reasons. Image File history File links Argiopesilk. ... Image File history File links Argiopesilk. ... Binomial name Argiope appensa (Walckenaer, 1842) Synonyms Epeira appensa Coganargiope reticulata Argiope appensa is a spider that occurs on several islands in the Western Pacific Ocean. ...


The Trapdoor spider will burrow into the ground and weave a trapdoor-like structure with spindles around so it can tell when prey arrives and take it by surprise. Diversity 9 genera, 120 species Genera Bothriocyrtum Cyclocosmia Ummidia Cteniza several others, see text Trapdoor spiders (superfamily Ctenizoidea, family Ctenizidae) are medium-sized mygalomorph spiders that construct burrows with a cork-like trapdoor made of soil, vegetation and silk. ...


Many small spiders use silk threads for ballooning. They extrude several threads into the air and let themselves become carried away with upward winds. Although most rides will end a few meters later, it seems to be a common way for spiders to invade islands. Many sailors have reported that spiders have been caught in their ship's sails, even when far from land. Ballooning is a term to describe the way many spider species disperse through the air. ...


Properties

 A garden spider spinning its web.
A garden spider spinning its web.
 Structure of spider silk. Inside a typical fiber, one finds crystalline regions separated by amorphous linkages. The crystals are beta-sheets that have assembled together.
Structure of spider silk. Inside a typical fiber, one finds crystalline regions separated by amorphous linkages. The crystals are beta-sheets that have assembled together.

Spider silk is also especially ductile, able to stretch up to 40% of its length without breaking. This gives it a very high toughness (or work to fracture), which according to "Liquid crystalline spinning of spider silk" (Nature, vol 410, p. 541), "equals that of commercial polyaramid (aromatic nylon) filaments, which themselves are benchmarks of modern polymer fiber technology." The notion that spider silk is stronger than any other fiber now known is thus erroneous, especially considering current research with carbon nanotubes that have yielded stronger fibers. Nonetheless, there is much interest in duplicating the silk process artificially, since spiders use renewable materials as input and operate at room temperature and low pressure. Spider silk can be harvested in large scale quantities if one has proper harvesting equipment. One can also make near indestructible spidersilk threads by weaving the fine threads into thicker and more durable ones in the same fashion as industrial threads are made today. ImageMetadata File history File links Download high resolution version (1024x768, 109 KB) Common garden spider, underside, spinning web. ... ImageMetadata File history File links Download high resolution version (1024x768, 109 KB) Common garden spider, underside, spinning web. ... Binomial name Araneus diadematus Clerck, 1757 The European garden spider (Araneus diadematus, cross spider) is a very common and well-known orb-weaver spider in Western Europe. ... Image File history File links Spider_silk_microscopic_structure. ... Image File history File links Spider_silk_microscopic_structure. ... Ductility is the physical property of being capable of sustaining large plastic deformations without fracture (in metals, such as being drawn into a wire). ... In materials science and metallurgy, toughness is the resistance to fracture of a material when stressed. ... 3D model of three types of single-walled carbon nanotubes. ...


Spider silk is made of complex protein molecules. This, coupled with the spider's preference—as a predatory animal—for isolation from other species, has made the study and replication of this substance quite challenging. Because of the repetitive nature of the DNA encoding the silk protein, it is difficult to determine its sequence, and the silk from only 14 species has been decoded. As of 2001 ten such sequences have been completed through a collaboration between the University of California at Riverside and the University of Wyoming. In 2005, indepedent researchers in University of Wyoming (Tian and Lewis), University of the Pacific (Hu and Vierra), the University of California at Riverside (Garb and Hayashi) and Shinshu University (Zhao and Nakagaki) uncovered the molecular structure of the gene for the protein that various female spider species use to make their silken egg cases. A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... In chemistry, a molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical bonds [1] [2] [3] [4] [5]. Chemical substances are not infinitely divisible into smaller fractions of the same substance: a molecule is generally considered the smallest particle of a pure... This snapping turtle is trying to make a meal of a Canada goose, but the goose is too wary. ... In biology, a species is one of the basic units of biodiversity. ... The structure of part of a DNA double helix Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living organisms. ... In genetics and biochemistry, sequencing means to determine the primary structure (or primary sequence) of an unbranched biopolymer. ... In biology, a species is one of the basic units of biodiversity. ... 2001 is a common year starting on Monday of the Gregorian calendar, and also: The International Year of the Volunteer The United Nations Year of Dialogue Among Civilizations Events January January 1 - A black monolith measuring approximately nine feet tall appears in Seattles Magnuson Park, placed by an anonymous... The University of California, Riverside is a public, coeducational university situated in Riverside, California beside Box Springs Mountain. ... The University of Wyoming is a land-grant university located in Laramie, Wyoming, situated on Wyomings high plains, at an elevation of 7,200 feet (2194 m), between the Laramie and Medicine Bow mountain ranges. ... The University of the Pacific (also known as Pacific, and formerly known as UOP) is a private northern California university originally chartered on July 10, 1851 in Santa Clara, California, under the name California Wesleyan College by the California Supreme Court. ...


Although different species of spider, and different types of silk, have different protein sequences, a general trend in spider silk structure is a sequence of amino acids (usually alternating glycine and alanine, or alanine alone) that self-assemble into a beta sheet conformation. These "Ala rich" blocks are separated by segments of amino acids with bulky side-groups. The beta sheets stack to form crystals, whereas the other segments form amorphous domains. It is the interplay between the hard crystalline segments, and the elastic amorphous regions, that gives spider silk its extraordinary properties. Glycine (Gly, G) is a nonpolar amino acid. ... Alanine (Ala, A) also 2-aminopropanoic acid is a non-essential α-amino acid. ... Self-assembly is the fundamental principle which generates structural organization on all scales from molecules to galaxies. ... Diagram of β-pleated sheet with H-bonding between protein strands The β sheet (also β-pleated sheet) is the second form of regular secondary structure in proteins — the first is the alpha helix — consisting of beta strands connected laterally by three or more hydrogen bonds, forming a generally twisted, pleated sheet. ... Crystal (disambiguation) Insulin crystals A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ... An amorphous solid is a solid in which there is no long-range order of the positions of the atoms. ...


Synthesis

The thread is released through silk glands. Many species of spider have different glands for different jobs, such as housing and web construction, defense, capturing and detaining prey, mobility and in extreme cases even as food.[citation needed] Thus, the silk needs to be specialized for the task at hand so success is guaranteed. This article is about yarn fiber. ... A gland is an organ in an animals body that synthesizes a substance for release such as hormones, often into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). ... In biology, a species is one of the basic units of biodiversity. ... Diversity 111 families, 40,000 species Suborders Mesothelae Mygalomorphae Araneomorphae  See table of families Closeup image of a Wolf Spider Wikispecies has information related to: Spiders Spiders are predatory invertebrate animals that have two body segments, eight legs, no chewing mouth parts and no wings. ... A spinneret is a spiders silk spinning organ. ... A house in Pathanapuram, Kerala (India) A house, a structure used for habitation by people, generally has walls and a roof to shelter its enclosed space from precipitation, wind, heat, and cold. ... Spider web with morning dew enhancing its visibility. ... Prey can refer to: Look up Prey in Wiktionary, the free dictionary A prey animal eaten by a predator in an act called predation. ...


The gland's visible, or external, part is termed the spinneret. Depending on the species, spiders will have anything from two to eight spinnerets, usually in pairs. The beginning of the gland is rich in thiol and tyrosine groups, the main ingredient to silk fiber. After this beginning process, the ampulla acts as a storage sac for the newly created fibers. From there, the spinning duct effectively removes water from the fiber and through fine channels also assists in its formation. Lipid secretions take place just at the end of the distal limb of the duct, and proceeds to the valve. The valve is believed to assist in rejoining broken fibers, acting much in the way of a helical pump. A spinneret is a spiders silk spinning organ. ... In biology, a species is one of the basic units of biodiversity. ... A spinneret is a spiders silk spinning organ. ... Sulfhydryl // In organic chemistry, a thiol is a compound that contains the functional group composed of a sulfur atom and a hydrogen atom (-SH). ... Tyrosine (from the Greek tyros, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in cheese[1][2]), 4-hydroxyphenylalanine, or 2-amino-3(4-hydroxyphenyl)-propanoic acid, is one of the 20 amino acids that are used by cells to synthesize proteins. ... The ampulla of Vater is a sphincter (a small muscle) where the common bile duct enters the duodenum. ... SAC can mean: S-Allyl cysteine, a chemical constituent of garlic SAC Capital Partners, a hedge fund managed by Steven A. Cohen SAC programming language St. ... A duct may refer to: An atmospheric duct. ... Impact of a drop of water. ... Lipids are a class of hydrocarbon-containing organic compounds. ... A duct may refer to: An atmospheric duct. ... These water valves are regulated by handles. ... A progressive cavity pump is a kind of pump which moves fluid by means of a cavity which progresses along the body of the pump. ...


Various compounds other than protein are used to enhance the fiber's properties. Pyrrolidine has hygroscopic properties and helps to keep the thread moist. It occurs in especially high concentration in glue threads. Potassium hydrogen phosphate releases protons in aqueous solution, resulting in a pH of about 4, making the silk acidic and thus protecting it from fungus and bacteria that would otherwise digest the protein. Potassium nitrate is believed to prevent the protein from denaturating in the acidic milieu.[1] Flash point 3 °C R/S statement R: 11 20/21/22 35 S: 16 26 28 36/37 45 RTECS number UX9650000 Related compounds Related compounds pyrrole piperidine Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and... A hygroscopic substance is a substance that absorbs water readily from its surroundings. ... General Name, Symbol, Number potassium, K, 19 Chemical series alkali metals Group, Period, Block 1, 4, s Appearance silvery white Atomic mass 39. ... This page meets Wikipedias criteria for speedy deletion. ... // Properties [1][2] In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... The correct title of this article is . ... Acidity redirects here. ... Divisions Chytridiomycota Zygomycota Glomeromycota Ascomycota Basidiomycota Deuteromycota The fungi (singular fungus) are a kingdom of eukaryotic organisms. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... R-phrases   S-phrases   Supplementary data page Structure and properties n, εr, etc. ...


The spinneret apparatus of a Araneus diadematus consists of the following glands: Binomial name Araneus diadematus Clerck, 1757 The European garden spider (Araneus diadematus, cross spider) is a very common and well-known orb-weaver spider in Western Europe. ...

  • 500 Glandulae piriformes for attachment points
  • 4 Glandulae ampullaceae for the web frame
  • about 300 Glandulae aciniformes for the outer lining of egg sacs, and for ensnaring prey
  • 4 Glandulae tubuliformes for egg sac silk
  • 4 Glandulae aggregatae for glue
  • 2 Glandulae coronatae for the thread of glue lines[2]

Human use

Peasants in the southern Carpathian Mountains used to cut up tubes built by Atypus and cover wounds with the inner lining. It reportedly facilitated healing, and even connected with the skin. This is believed to be due to antiseptic properties of spider silk (which is made of protein)[1] Some fishermen in the indo-pacific ocean use the web of Nephila to catch small fish.[1] Spider silk, normally that of the golden orb spider, is occasionally harvested and spun into usable textiles. Due to the difficulty of the process, the resulting fabric is invariably extremely expensive, and is generally utilized in fine couture. Satellite image of the Carpathians. ... Species N. clavata N. clavipes N. edulis N. inaurata N. maculata N. pilipes The golden silk orb-weavers (genus Nephila) are also commonly called golden orb-weavers or banana spiders. ...


Artificial spider silk

Spider silk's properties have made it the target of industrial research efforts. It is not generally considered possible to use spiders themselves to produce industrially useful quantities of spider silk, due to the difficulties of managing large quantities of small spiders (although it was tried with Nephila silk[1]). It is thought that using one large genetically engineered "super-spider" would be more practical. Compared to silkworms, spiders are aggressive and will eat one another, making it inadvisable to keep many small spiders together in the same space. Other efforts have involved extracting the spider silk gene and using other organisms to produce the required amount of spider silk. In 2000, Nexia, a Canadian biotechnology company, was successful in producing spider silk protein in transgenic goats. These goats carried the gene for spider silk protein, and the milk produced by the goats contained significant quantities of the protein. Attempts to spin the protein into a fiber similar to natural spider silk failed, however. The spider's highly sophisticated spinneret is instrumental in organizing the silk proteins into strong domains. Specifically, the spinneret creates a gradient of protein concentration, pH, and pressure, which drive the protein solution through liquid crystalline phase transitions, ultimately generating the required silk structure (which is a mixture of crystalline and amorphous biopolymer regions). Replicating these complex conditions in lab environment has proved difficult. Nexia attempted to press the pherotein solution through small extrusion holes in order to simulate the behavior of the spinneret, but this was insufficient to properly organize the fibers. Ultimately, Nexia was forced to abandon research on artificial spider silk, despite having successfully created the silk protein in genetically modified organisms. Species N. clavata N. clavipes N. edulis N. inaurata N. maculata N. pilipes The golden silk orb-weavers (genus Nephila) are also commonly called golden orb-weavers or banana spiders. ... Binomial name Bombyx mori Linnaeus, 1758 For the band named Silkworm, see Silkworm (band). ... For other meanings of this term, see gene (disambiguation). ... This article is about the year 2000. ... The structure of insulin Biotechnology is technology based on biology, especially when used in agriculture, food science, and medicine. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... A genetically modified organism is an organism whose genetic material has been deliberately altered. ... Species See Species and subspecies The goat is a mammal in the genus Capra, which consists of nine species: the Ibex, the West Caucasian Tur, the East Caucasian Tur, the Markhor, and the Wild Goat. ... In chemistry, concentration is the measure of how much of a given substance there is mixed with another substance. ... The correct title of this article is . ... The use of water pressure - the Captain Cook Memorial Jet in Lake Burley Griffin, Canberra. ... Schlieren texture of Liquid Crystal nematic phase Liquid crystals are substances that exhibit a phase of matter that has properties between those of a conventional liquid, and those of a solid crystal. ... In physics, a phase transition is the transformation of a thermodynamic system from one phase to another. ... Quartz crystal Copper(II) sulfate and iodine crystal Synthetic bismuth crystal Insulin crystals Gallium, a metal that easily forms large single crystals A huge monocrystal of potassium dihydrogen phosphate grown from solution by Saint-Gobain for the megajoule laser of CEA. In chemistry and mineralogy, a crystal is a solid... An amorphous solid is a solid in which there is no long-range order of the positions of the atoms. ... Biopolymers are a special class of polymers produced by living organisms. ... Genetic engineering, genetic modification (GM), and gene splicing (once in widespread use but now deprecated) are terms for the process of manipulating genes in an organism, usually outside of the organisms normal reproductive process. ...


See also

  • Hagfish - produces similar fiber.

Genera Eptatretus Myxine Nemamyxine Neomyxine Notomyxine Paramyxine Quadratus This article is about the Hagfish. ...

References

  1. ^ a b c d Heimer, S. (1988). Wunderbare Welt der Spinnen. Urania. p.12
  2. ^ Heimer, S. (1988). Wunderbare Welt der Spinnen. Urania p.12
  • Forbes, Peter (4th Estate, London 2005) 'The Gecko's Foot - Bio Inspiration: Engineered from Nature' ISBN 0-00-717990-1 in H/B

August 15 is the 227th day of the year in the Gregorian Calendar (228th in leap years), with 138 days remaining. ... For album titles with the same name, see 2002 (album). ... First title page, November 4, 1869 Nature is one of the oldest and most reputable scientific journals, first published on 4 November 1869. ...

External links

Wikinews has news related to:
Spiders' egg case silk gene found
  • The Silk Gland - A very nice breakdown of the silk gland, its parts and uses with images and drawings.
  • Spiders in Space - NASA article and database information on the research of spiders in space.
  • Production of spider silk proteins in tobacco and potato - Article on nature.com
  • Israeli and German scientists created artificial silk using genetically engineered spider proteins - Article on IsraCast
  • The mechanical design of spider silks: from fibroin sequence to mechanical function - Article on The Journal of Experimental Biology
  • The Real Spider-Man - Article on forming Spider Silk Fibers from Caterpillars
  • Genetic tweak boosts stiffness of spider silk
  • Silk & Webs - The Arachnology Home Page

  Results from FactBites:
 
Access Excellence: Science Updates Archive (497 words)
Dragline silk is the fiber from which spiders make the scaffolding of their webs.
Tirrell reports that the primary constituents of spider silk turn out to be the two simplest amino acids, glycine and alanine, and he notes that researchers at Cornell have recently discovered that the alignment of these amino acids is responsible for spider silk's incredible strength.
Spider silk, for instance, could be made in the lab by taking an arachnid's genes and inserting them into bacteria to produce that insect's strong, durable thread.
Spider Silk (0 words)
All spiders possess spinning glands and make silk, they use it for a safety dragline, to fly, for making a highly durable cocoon for their eggs, to line their homes, to trap their prey and to immobilise their victims.
With all these things considered we learn that the tensile strength of spider silk under normal laboratory conditions is slightly less than steel if you compare it in terms of the threads diametre, but it is far greater than that of steel if you compare it in terms of the weight of the thread.
Spiders that possess a cribellum are called 'Cribellate', as compared with the remaining spiders which are sometimes referred to as 'Ecribellate'.
  More results at FactBites »

 
 

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