Kinds Of Silk Research Articles

Secretion of dermal glands in freshwater mites (acariformes, parasitengonina, hydrachnidia) and its structural characteristics

Freshwater mites, single possessors of dermal glands in Parasitengonina, demonstrate production of special filamentous substance, which may be characterized as silk. The silk secretion and silk stricture in water mites are described and analyzed in comparison with other arthropods. A single silk thread has the simplest organization among that of other arthropods - it is an infinitely long unbranched uniform hollow tube, the walls of which are composed of fine fibrils crossing at different angles to each other. Although silk in water mites does not form a structural organized web as in spiders, it is highly likely that in mass production it serves for capturing prey - small water arthropods. This kind of silk - is a new discovered type of arthropod silk, and the ability of silk production has elaborated in water mites after their ancestors have invaded and mastered the aquatic environment. This property greatly expands the possibilities in the competition for resources.

The Properties and Application of Natural Spider Silk: a Literature Review

Drag silk, which is produced by the main ampullate silk gland, is a kind of natural insect silk which outperforms some other kinds of silk. Given its exceptional mechanical characteristics and excellent biocompatibility, drag silk, a kind of spider silk, does have the potential to be utilized by humans. The excellent properties of natural spider silk make it useful in many fields. But due to the cannibalistic nature of spiders, spiders cannot be reared on a large scale to meet the huge demand for spider silk. The development of recombinant spider silk protein and artificial spider silk through research and development is vital for the commercialization of spider silk and its applications. This research outlines the possible applications of natural spider silk by examining its physical, biological, and characteristic features. Due to its extraordinary physical and biological properties, drag silk and its corresponding silk proteins have been found to have the potential for the applications in the aerospace industry and biomedical treatments.

Identification and characterization of sericin5 reveals non-cocoon silk sericin components with high β-sheet content and adhesive strength

Sericins are glue proteins on the surface of silk fibers. Four sericins have been characterized in silkworm, namely sericin1 (Ser1), sericin2 (Ser2), sericin3 (Ser3), and sericin4 (Ser4). In this study, we report a novel sericin, sericin5 (Ser5), which exists only in non-cocoon silk. We describe the sequence, exon-intron structure, and translation products of Ser5 in Bombyx mori. The Ser5 gene is approximately 22-kb long and comprises 16 exons. Ser5 protein has a size of 260 kDa, as determined by SDS-PAGE, western blot, and LC-MS/MS. Immunofluorescence analysis revealed that Ser5 co-localizes with Ser1 in the sericin layer. The expression pattern of Ser5 was detected at the transcriptional and translational levels. We systematically analyzed and compared the amino acid composition, repeat regions, and hydrophilicity of silkworm sericins. Morphological observations showed that non-cocoon silk had more sericin than cocoon silk. Circular dichroism spectra revealed that non-cocoon silk sericin contained more β-sheet structures than cocoon silk sericin. In addition, we found that the hydrophilicity and adhesive strength of native sericin increases gradually from the inner layer to the outer layer. This research enhances our understanding of various sericins from cocoon silk and non-cocoon silk with regard to their expression patterns, hydrophilicity, secondary structure and adhesive performances. Statement of significanceSericin is a natural biomaterial with diverse biological properties, which has long been used as tissue engineering and biomedical applications. However, the composition and distribution of sericins in different kinds of silk are still uncertain, and the properties difference between sericins have not yet been reported. Our study makes a significant contribution to the literature as it identifies the sequence, composition, hydrophilicity and adhesive property of sericins. Moreover, it provides key insights into the structure-function and function-distribution relationships associated with sericins. We believe that this study will arouse the interest to the readership of your journal as it identifies the new complete sequence of sericin and revealed the composition and properties of sericin, thus highlighting their future potentials applications in both the biomaterial and technical fields.

Phantoms in the Classroom: Midwifery Training in Enlightenment Europe

Phantoms in the Classroom: Midwifery Training in Enlightenment Europe

Environmentally responsive composite films fabricated using silk nanofibrils and silver nanowires

Two kinds of silk nanofibril/silver nanowire composite films were fabricated by using a facile vacuum-filtration method, and can act as a humidity sensor or a pressure sensor.

Silk recycling in larvae of the wax moth, Galleria mellonella (Lepidoptera: Pyralidae)

Galleria mellonella larvae spin protective tubes, which they use until they finish feeding, when they spin cocoons. A feeding choice experiment showed that some of the silk produced by feeding larvae was consumed in addition to the standard diet (STD). To determine the effect of feeding on silk, last instar larvae were fed for 24 h on foods based on STD but modified by replacing the dry milk component (10% of the diet) with equal amounts of different kinds of silk. While each control larva consumed 21 ± 0.5 mg of the STD and produced 4.5 ± 0.1 mg of silk, larvae that ate the food that contained larval silk consumed 10 ± 0.4 mg of food and produced 6.1 ± 0.1 mg silk; the percentage ratio of silk produced to diet consumed was 21% and 61%, respectively. A more pronounced reduction in food consumption occurred when larvae were supplied with Galleria silk or the sericin fraction of such silk, and only 3.8 mg/larva was ingested of the diet containing Bombyx mori cocoon silk or its sericin fraction. Silk production expressed in terms of percentage of diet consumed was always higher than that recorded for larvae fed STD. We conclude that G. mellonella larvae recycle part of the silk that they produce during feeding. Presence of silk in the diet reduces food intake but increases the ratio of silk production to diet consumption. Sericin fraction of the cocoon silk seems to deter feeding.

A Study on the Types, Sizes and Materials of Honor Guard Flags for the Crown Prince in the late Joseon Period

The study aims to examine the types, sizes and materials of honor guard flags for the Crown Prince in the Late Joseon based on “Crown Prince Munhyo’s Chaekrye Dogam Uigwe.” The findings are as follows: As the records on honor guard flags in Crown Prince Munhyo’s Chaekrye Dogam Uigwe specify the types, quantities and usage of materials, it is considered to be a valuable document that can be referenced for the purpose of reproducing the flags of honor for the Crown Prince. The Crown Prince’s honor guard flags include a total of ten flags of six different types, featuring Giringi, Baektaekgi, Hyeonhakgi, Baekhakgi, Gaguiseoningi and Yeongjagi. Yeongjagi takes the shape of a right-angled trapezoid, and the remainder take the form of a rectangle. Excluding the Yeongjagi, the background of the five honor guard flags is white. The collar is black, the tail is red and the tied string is red against the background of icons. Yeongjagi has a red collar against the red background where a Chinese character “令(Young)” is written in black, and it takes the form of a right-angled trapezoid. By size, Yeongjagi is a small flag, while the other flags are medium-sized. The background of the medium sized flags is 167.3 to 196.8 ㎝ in width and 148 to 164.5 ㎝ in length. The upper edge of the Yeongjagi is 162.4 ㎝ in width, its lower edge is 103.3 ㎝ in width, and its length is 98.7 ㎝. The flags are made with Jeongju, a kind of silk. Ten types of pigments were used to draw the icons on the background. The handle was made with a medium-sized bamboo pole painted in black, and the top of the handle, which was made with a piece of walnut wood, was painted in red. The storage case for an honor guard flag was made with blue cotton, and the rain cover for an honor guard flag was made with thick oilpaper.

Genome engineering and parthenocloning in the silkworm, Bombyx mori.

Genetic engineering of the silkworm, Bombyx mori, opens door to the production of new kinds of silk and to the use of silkworms as proteosynthetic bioreactors. The insertion of foreign genes into silkworm genome and the control of their expression by diverse promoters have become possible but are not yet efficient enough for commercial use. Several methods of gene targeting are being developed to minimize position effect on transgene expression and facilitate cloning. Parthenocloning can be exploited to conserve genetic traits and improve selection and amplification of clones containing genes of interest. Some silkworm clones have been bred for decades as genetically stable female stocks whose unfertilized eggs are induced to develop by heat-shock treatment. Any exclusively female generation contains exact copies of the maternal clone-founder genome. Ovaries transplanted in either direction between the standard and the parthenogenetic genotypes yield eggs capable of parthenocloning. In addition, use ofmale larvae as ovary recipients eliminates diapause in eggs produced in the implants. Unfertilized eggs of some silkworm clones respond also to the cold-shock treatment by producing homozygous fertile sons; cloned females can be crossed with their parthenogenetic sons to obtain progeny homozygous for the transgene in both sexes. Rational exploitation of available parthenozygous pools and the use of parthenocloning methods enable rapid fixation and maintenance of the desired genotypes.

PRELIMINARY REARING TECHNIQUE FOR ATTACUS ATLAS (LEPIDOPTERA: SATURNIIDAE) A WILD SILK WORM OF INDIA

Sericulture is agro based industry. India is the only country where all four kinds of silks viz. Mulberry, Muga, Tasar and Eri are commercially exploited. Attacus atlas, Linnaeus (Lepidoptera: Saturniidae) is wild silk worm of India. Its conservation and exploitation in silk production is essential component of wild silk technology development in India. Therefore, rearing technique of A. atlas has been given in the paper. Cocoons were formed within 35-43 days. Cocoon weight, shell weight, shell length, shell width and shell thickness were 9.4 g, 1.82 g, 4.4 cm, 1.4 cm and 0.21 mm respectively, while shell ratio calculated was 19.32%. The rearing success of A. atlas was 15% on Angeer Ficus carica. The mated females laid 147 eggs and produced 22 offspring’s with an average sex ratio (m: f) 1: 0.75.

The Conservation Methods of Ancient Lu Embroidery Fabric

As a kind of silk, Lu Embroider is an valuable cultural heritage. This textile adequately approves the advancement of Chinese civilization. At the same time, Lu Embroider is easy decayed. We lack the consciousness of protecting the cultural heritage. In this paper, the reasons and significance of conservation ancient Lu Embroider fabric are introduced. The correspond conservation methods also is presented at the same time.

The Cultural Exchange between Sino-Western: Silk Trade in Han Dynasty

As we all know, the Silk Road, as a famous ancient transportation route, was a trade line cross-Eurasian continent in history. Its name was from the delivery of silk. However, no Chinese ancient documents mentioned the name of “Silk Road”. German F. V. Richthofen (1933-1905) firstly used the term “Silk Road” in his book China, published in 1877. Afterwards, the name of “Silk Road” has been accepted universally and used by the world widely. The Silk Road was an ancient business channel, acrossing the middle of China and countries in Central Asia, gradually forming after Qian Zhang visited Western Regions twice, two thousand and one hundred years ago. The north-west land Silk Road started from Chinese ancient Capital Chang’an (now Xi’an), acrossing Central Asia, and reaching ancient Rome in Europe. It was a bridge for communication of politics, economy, and culture between ancient China and the Western. Before 11 Century, the Sino-Western silk trade mainly depended on the land transportation. During Han Dynasty, it was a competition between the Huns and the Hans for occupy the Silk road. The silk as a kind of material culture was a sort of intermediary for making people to know how to get along together.This article attempts to describe the Sino-Western silk trade conditions before and after the two missions of Qian Zhang to Western Regions (Xiyu), including archaeological evidences, kinds of silk and trade scale, transportation routes, trade participants, and so on.

A MaSp2-like gene found in the Amazon mygalomorph spider Avicularia juruensis

Two unique spidroins are present in the silk of the Amazon mygalomorph spider - Avicularia juruensis (Theraphosidae), and for the first time the presence and expression of a major ampullate spidroin 2-like in Mygalomorphae are demonstrated. Molecular analysis showed the presence of (GA)(n,) poly-A and GPGXX motifs in the amino acid sequence of Spidroin 2, the last being a motif described so far only in MaSp2 and Flag spidroins. Phylogenetic analysis confirmed the previously known orthologous silk gene clusters, and placed this gene firmly within the orbicularian MaSp2 clade. Gene tree-species tree reconciliations show a pattern of multiple gene duplication throughout spider silk evolution, and pinpoint the oldest speciation in which MaSps must have been present in spiders on the mygalomorph-araneomorph split, 240 MYA. Therefore, while not refuting orb weaver monophyly, MaSp2s, and major ampullate silks in general cannot be classified as orbicularian synapomorphies, but have to be considered plesiomorphic for Opisthothelae. The evidence presented here challenges the simplified notion that mygalomorphs spin only one kind of silk, and adds to the suite of information suggesting a pattern of early niche diversification between Araneomorphae and Mygalomorphae. Additionally, mygalomorph MaSp2-like might accommodate mechanical demands arising from the arboreal habitat preference of Avicularia.

Reconstructing web evolution and spider diversification in the molecular era

The evolutionary diversification of spiders is attributed to spectacular innovations in silk. Spiders are unique in synthesizing many different kinds of silk, and using silk for a variety of ecological functions throughout their lives, particularly to make prey-catching webs. Here, we construct a broad higher-level phylogeny of spiders combining molecular data with traditional morphological and behavioral characters. We use this phylogeny to test the hypothesis that the spider orb web evolved only once. We then examine spider diversification in relation to different web architectures and silk use. We find strong support for a single origin of orb webs, implying a major shift in the spinning of capture silk and repeated loss or transformation of orb webs. We show that abandonment of costly cribellate capture silk correlates with the 2 major diversification events in spiders (1). Replacement of cribellate silk by aqueous silk glue may explain the greater diversity of modern orb-weaving spiders (Araneoidea) compared with cribellate orb-weaving spiders (Deinopoidea) (2). Within the "RTA clade," which is the sister group to orb-weaving spiders and contains half of all spider diversity, >90% of species richness is associated with repeated loss of cribellate silk and abandonment of prey capture webs. Accompanying cribellum loss in both groups is a release from substrate-constrained webs, whether by aerially suspended webs, or by abandoning webs altogether. These behavioral shifts in silk and web production by spiders thus likely played a key role in the dramatic evolutionary success and ecological dominance of spiders as predators of insects.

Spidroins from the Brazilian spider Nephilengys cruentata (Araneae: Nephilidae)

Spiders produce up to six different kinds of silk, each one for a specific biological function. Spider silks are also known for their unique mechanical properties. The possibility of producing new materials with similar properties motivated research on these silk proteins (spidroins). Using expression sequence tags, we identified four spidroins produced by major ampullate, minor ampullate, flagelliform and tubuliform silk glands from the Brazilian spider Nephilengys cruentata (Araneae: Nephilidae). The new protein sequences showed substantial similarity to other spidroins previously described, with high content of alanine and glycine due to the presence of the highly repetitive motifs (polyAla, (GA) n, (GGX) n, (GPGGX) n). Similarities among sequences were also observed between the different spidroins with the exception of tubuliform spidroin, which presents a unique complex amino acid sequence with high amounts of serine and low amounts of glycine.

Tightly winding structure of sequential model peptide for repeated helical region in Samia cynthia ricini silk fibroin studied with solid‐state NMR

There are many kinds of silks from silkworms and spiders with different structures and properties, and thus, silks are suitable to study the structure-property relationship of fibrous proteins. Silk fibroin from a wild silkworm, Samia cynthia ricini, mainly consists of the repeated similar sequences by about 100 times where there are alternative appearances of the polyalanine (Ala)(12-13) region and the Gly-rich region. In this paper, a sequential model peptide, GGAGGGYGGDGG(A)(12)GGAGDGYGAG, which is a typical sequence of the silk fibroin, was synthesized, and the atomic-level conformations of Gly residues at the N- and C-terminal ends of the polyalanine region were determined as well as that of the central Ala residue using (13)C 2D spin diffusion solid-state nuclear magnetic resonance (NMR) under off-magic angle spinning. In the model peptide with alpha-helical conformation, the torsion angle of the central Ala residue, the 19th Ala, was determined to be (phi, psi) = (-60 degrees, -50 degrees ), which was a typical alpha-helical structure, but the torsion angles of two Gly residues, the 12th and 25th Gly residues, which are located at the N- and C-terminal ends of the polyalanine region, were determined to be (phi, psi) = (-70 degrees, -30 degrees ) and (phi, psi) = (-70 degrees, -20 degrees ), respectively. Thus, it was observed that the turns at both ends of polyalanine with alpha-helix conformation in the model peptide are tightly wound.

Synthesizing spider silk

Spider silks have remarkable mechanical properties that make them attractive for medical, military and industrial applications. All spiders can make seven kinds of silk, one type to wrap its prey, one to wrap its eggs and five to construct the web. Each type is biologically engineered to perform its task to perfection. ‘Capture’ silk, which is used to snare insects, is very sticky and can stretch three times its length before breaking. ‘Dragline’ silk, used to anchor the web and form its spokes, has a higher tensile strength than high-tensile steel of the same weight. The protein core of dragline silk fibers is secreted as a mixture of two soluble proteins from epithelial cells in specialized glands. The spinneret, a sophisticated apparatus, transforms the water-soluble silk proteins into the insoluble, strong threads that make up webs. The different silk proteins contain repetitive amino acid sequences that vary slightly, depending on their use. These small changes in sequence can confer different mechanical properties.

PIXE analysis of silk

The method of proton-induced X-ray emission (PIXE) was first utilized to analyze the elements in silk. Different kinds of silk from home and the wild were examined. The results show that every silk, besides C, H, O, and N, contains many types of elements such as Si, P. S, Ca, Mn, Fe, Cu, Zn, and Sr and different samples have different relative contents. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 405–408, 1997

The silk-producing system ofLinyphia triangularis (Araneae, Linyphiidae) and some comparisons with Araneidae

The spinning apparatus ofLinyphia triangularis, adult females and males, was studied with the scanning electron microscope and the main anatomical and histochemical characteristics of the silk glands, including the epigastric apparatus of males, are presented. The epigastric glands seem to be important for the construction of sperm webs. A detailed account of the use of the different kinds of silk in web building is given. The spinning apparatus ofLinyphia closely corresponds to the araneid pattern. Characteristic of linyphiid spiders is the poor development of the aciniform glands. Corresponding to the minor importance of capture threads forLinyphia, the triads (aggregate and flagelliform glands) are less developed than in Araneidae.Linyphia make much less use of the secretions of the piriform glands for connecting threads than Araneidae. Capture threads adhere to other threads by their own glue; other threads seem mostly to be bound to one another by the secretion of the minor ampullate glands whose chemical properties, inLinyphia, appear especially adapted to this function. Neither the anatomical and histochemical data concerning the spinning apparatus nor the structure of the webs provide any indication of close relationships between Linyphiidae and Agelenidae, as was recently claimed.

Configurations of silk fibroins and synthetic polypeptides

The infra-red spectra of a number of different kinds of silk are compared with spectra of synthetic polypeptides prepared from L-alanine and glycine. It is shown that the molecular configuration depends on the composition of the material and on the solvent used for the preparation of the specimen. In the case of films of water-soluble Antherea mylitta (tussah) silk, there is strong evidence for α-helices consisting mainly of L-alanine residues. These results are discussed in relation to the configuration of the molecules in solution.

Silk-producing Insects of West Africa

THE following observations in connection with the wild silk-producing insects of West Africa may be considered of interest. In parts of Nigeria (Ibadan, Ilorin, &c.) the cocoons of Anaphe infracta, Wlsm., and A. venata, Butler, are used for the production of a cloth termed “Sanyan,” which is woven from yarn, spun from the boiled cocoon masses, mixed with native cotton yarns. In a state of nature the silk from the cocoons of both these species is brown or yellow-brown, and is of this colour when exposed for sale in the markets, but another kind of silk, which is brought to Ibadan from Bauchi and Bornu (in N. Nigeria), is pure white in colour, and is called “Gambari,” or Haussa silk. This is only obtainable as boiled cocoon masses, and the dried remains of the worms found in them seem to indicate that they are allied to Anaphe. The collectors of this silk are said to gather the worms from the trees, on which they find them, when they are prepared to spin, and to confine them in calabashes.