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Sample records for instar silk glands

  1. MicroRNA of the fifth-instar posterior silk gland of silkworm identified by Solexa sequencing

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    Jisheng Li

    2014-12-01

    Full Text Available No special studies have been focused on the microRNA (miRNA in the fifth-instar posterior silk gland of Bombyx mori. Here, using next-generation sequencing, we acquired 93.2 million processed reads from 10 small RNA libraries. In this paper, we tried to thoroughly describe how our dataset generated from deep sequencing which was recently published in BMC genomics. Results showed that our findings are largely enriched silkworm miRNA depository and may benefit us to reveal the miRNA functions in the process of silk production.

  2. Silk formation mechanisms in the larval salivary glands of Apis ...

    Indian Academy of Sciences (India)

    Unknown

    The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands were dissected and prepared for light and polarized light microscopy, as well as for scanning and transmission electron microscopy. The results showed that silk formation starts at the middle of the 5th ...

  3. Silk formation mechanisms in the larval salivary glands of Apis ...

    Indian Academy of Sciences (India)

    Unknown

    The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands .... be used in the silk-manufacture industry. This paper analyses .... (figure 3C); and are highly birefringent (figure 3D).

  4. Analysis of proteome dynamics inside the silk gland lumen of Bombyx mori

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    Dong, Zhaoming; Zhao, Ping; Zhang, Yan; Song, Qianru; Zhang, Xiaolu; Guo, Pengchao; Wang, Dandan; Xia, Qingyou

    2016-01-01

    The silk gland is the only organ where silk proteins are synthesized and secreted in the silkworm, Bombyx mori. Silk proteins are stored in the lumen of the silk gland for around eight days during the fifth instar. Determining their dynamic changes is helpful for clarifying the secretion mechanism of silk proteins. Here, we identified the proteome in the silk gland lumen using liquid chromatography–tandem mass spectrometry, and demonstrated its changes during two key stages. From day 5 of the fifth instar to day 1 of wandering, the abundances of fibroins, sericins, seroins, and proteins of unknown functions increased significantly in different compartments of the silk gland lumen. As a result, these accumulated proteins constituted the major cocoon components. In contrast, the abundances of enzymes and extracellular matrix proteins decreased in the silk gland lumen, suggesting that they were not the structural constituents of silk. Twenty-five enzymes may be involved in the regulation of hormone metabolism for proper silk gland function. In addition, the metabolism of other non-proteinous components such as chitin and pigment were also discussed in this study. PMID:27102218

  5. Fabrication and characterization of biomaterial film from gland silk of muga and eri silkworms.

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    Dutta, Saranga; Talukdar, Bijit; Bharali, Rupjyoti; Rajkhowa, Rangam; Devi, Dipali

    2013-05-01

    This study discusses the possibilities of liquid silk (Silk gland silk) of Muga and Eri silk, the indigenous non mulberry silkworms of North Eastern region of India, as potential biomaterials. Silk protein fibroin of Bombyx mori, commonly known as mulberry silkworm, has been extensively studied as a versatile biomaterial. As properties of different silk-based biomaterials vary significantly, it is important to characterize the non mulberry silkworms also in this aspect. Fibroin was extracted from the posterior silk gland of full grown fifth instars larvae, and 2D film was fabricated using standard methods. The films were characterized using SEM, Dynamic contact angle test, FTIR, XRD, DSC, and TGA and compared with respective silk fibers. SEM images of films reveal presence of some globules and filamentous structure. Films of both the silkworms were found to be amorphous with random coil conformation, hydrophobic in nature, and resistant to organic solvents. Non mulberry silk films had higher thermal resistance than mulberry silk. Fibers were thermally more stable than the films. This study provides insight into the new arena of research in application of liquid silk of non mulberry silkworms as biomaterials. Copyright © 2012 Wiley Periodicals, Inc.

  6. DNA replication events during larval silk gland development in the silkworm, Bombyx mori.

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    Zhang, Chun-Dong; Li, Fang-Fang; Chen, Xiang-Yun; Huang, Mao-Hua; Zhang, Jun; Cui, Hongjuan; Pan, Min-Hui; Lu, Cheng

    2012-07-01

    The silk gland is an important organ in silkworm as it synthesizes silk proteins and is critical to spinning. The genomic DNA content of silk gland cells dramatically increases 200-400 thousand times for the larval life span through the process of endomitosis. Using in vitro culture, DNA synthesis was measured using BrdU labeling during the larval molt and intermolt periods. We found that the cell cycle of endomitosis was activated during the intermolt and was inhibited during the molt phase. The anterior silk gland, middle silk gland, and posterior silk gland cells asynchronously exit the endomitotic cycle after day 6 in 5th instar larvae, which correlated with the reduced expression of the cell cycle-related cdt1, pcna, cyclin E, cdk2 and cdk1 mRNAs in the wandering phase. Additional starvation had no effect on the initiation of silk gland DNA synthesis of the freshly ecdysed larvae. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Critical electrolyte concentration of silk gland chromatin of the sugarcane borer Diatraea saccharalis, induced using agrochemicals.

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    Santos, S A; Fermino, F; Moreira, B M T; Araujo, K F; Falco, J R P; Ruvolo-Takasusuki, M C C

    2014-09-29

    The sugarcane borer Diatraea saccharalis is widely known as the main pest of sugarcane crop, causing increased damage to the entire fields. Measures to control this pest involve the use of chemicals and biological control with Cotesia flavipes wasps. In this study, we evaluated the insecticides fipronil (Frontline; 0.0025%), malathion (Malatol Bio Carb; 0.4%), cipermetrina (Galgotrin; 10%), and neem oil (Natuneem; 100%) and the herbicide nicosulfuron (Sanson 40 SC; 100%) in the posterior region silk glands of 3rd- and 5th-instar D. saccharalis by studying the variation in the critical electrolyte concentration (CEC). Observations of 3rd-instar larvae indicated that malathion, cipermetrina, and neem oil induced increased chromatin condensation that may consequently disable genes. Tests with fipronil showed no alteration in chromatin condensation. With the use of nicosulfuron, there was chromatin and probable gene decompaction. In the 5th-instar larvae, the larval CEC values indicated that malathion and neem oil induced increased chromatin condensation. The CEC values for 5th-instar larvae using cipermetrina, fipronil, and nicosulfuron indicated chromatin unpacking. These observations led us to conclude that the quantity of the pesticide does not affect the mortality of these pests, can change the conformation of complexes of DNA, RNA, and protein from the posterior region of silk gland cells of D. saccharalis, activating or repressing the expression of genes related to the defense mechanism of the insect and contributing to the selection and survival of resistant individuals.

  8. The effect of gamma irradiation on some morphological and quantitative changes of Bombyx mori L. silk gland

    International Nuclear Information System (INIS)

    Petkov, N.; Malinova, K.; Binkh, N.

    1996-01-01

    A study to determine the effect of gamma irradiation of silkworm eggs at doses of 1.00; 2.00 and 3.00 on silk gland weight, length and width is performed. It was found that gamma irradiation of eggs in the stage of embryo most intensive growth in length (B 2 ) at doses 2.00 and 3.00 Gy stimulates increasing of silk glands weight in silkworms on the fifth day instar by 12-25 mg, as well as the silk worm width - by 7-33 μm, which is of significant importance for the synthesis and secretion of silk proteins (fibroin and sericin). A breed specificity was also observed

  9. Preparation of Porous Scaffolds from Silk Fibroin Extracted from the Silk Gland of Bombyx mori (B. mori

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    Liangjun Zhu

    2012-06-01

    Full Text Available In order to use a simple and ecofriendly method to prepare porous silk scaffolds, aqueous silk fibroin solution (ASF was extracted from silk gland of 7-day-old fifth instar larvae of Bombyx mori (B. mori. SDS-page analysis indicated that the obtained fibroin had a molecular weight higher than 200 kDa. The fabrication of porous scaffolds from ASF was achieved by using the freeze-drying method. The pore of porous scaffolds is homogenous and tends to become smaller with an increase in the concentration of ASF. Conversely, the porosity is decreased. The porous scaffolds show impressive compressive strength which can be as high as 6.9 ± 0.4 MPa. Furthermore, ASF has high cell adhesion and growth activity. It also exhibits high ALP activity. This implies that porous scaffolds prepared from ASF have biocompatibility. Therefore, the porous scaffolds prepared in this study have potential application in tissue engineering due to the impressive compressive strength and biocompatibility.

  10. Regulation of Silk Genes by Hox and Homeodomain Proteins in the Terminal Differentiated Silk Gland of the Silkworm Bombyx mori

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    Takiya, Shigeharu; Tsubota, Takuya; Kimoto, Mai

    2016-01-01

    The silk gland of the silkworm Bombyx mori is a long tubular organ that is divided into several subparts along its anteroposterior (AP) axis. As a trait of terminal differentiation of the silk gland, several silk protein genes are expressed with unique regional specificities. Most of the Hox and some of the homeobox genes are also expressed in the differentiated silk gland with regional specificities. The expression patterns of Hox genes in the silk gland roughly correspond to those in embryogenesis showing “colinearity”. The central Hox class protein Antennapedia (Antp) directly regulates the expression of several middle silk gland–specific silk genes, whereas the Lin-1/Isl-1/Mec3 (LIM)-homeodomain transcriptional factor Arrowhead (Awh) regulates the expression of posterior silk gland–specific genes for silk fiber proteins. We summarize our results and discuss the usefulness of the silk gland of Bombyx mori for analyzing the function of Hox genes. Further analyses of the regulatory mechanisms underlying the region-specific expression of silk genes will provide novel insights into the molecular bases for target-gene selection and regulation by Hox and homeodomain proteins. PMID:29615585

  11. Regulation of Silk Genes by Hox and Homeodomain Proteins in the Terminal Differentiated Silk Gland of the Silkworm Bombyx mori

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    Shigeharu Takiya

    2016-05-01

    Full Text Available The silk gland of the silkworm Bombyx mori is a long tubular organ that is divided into several subparts along its anteroposterior (AP axis. As a trait of terminal differentiation of the silk gland, several silk protein genes are expressed with unique regional specificities. Most of the Hox and some of the homeobox genes are also expressed in the differentiated silk gland with regional specificities. The expression patterns of Hox genes in the silk gland roughly correspond to those in embryogenesis showing “colinearity”. The central Hox class protein Antennapedia (Antp directly regulates the expression of several middle silk gland–specific silk genes, whereas the Lin-1/Isl-1/Mec3 (LIM-homeodomain transcriptional factor Arrowhead (Awh regulates the expression of posterior silk gland–specific genes for silk fiber proteins. We summarize our results and discuss the usefulness of the silk gland of Bombyx mori for analyzing the function of Hox genes. Further analyses of the regulatory mechanisms underlying the region-specific expression of silk genes will provide novel insights into the molecular bases for target-gene selection and regulation by Hox and homeodomain proteins.

  12. The effect of thyroxine on silk gland and the effect of two thyroxine ...

    African Journals Online (AJOL)

    The influence of feeding mulberry leaves treated with thyroxine to the growth of the silk gland, and the effect of two different mulberry species, that is, Morus nigra and Morus multicaulis treated with thyroxine on silk quality in the silkworm were studied. The silk glands from thyroxine treated Bombyx mori larvae weighed ...

  13. Silks produced by insect labial glands

    Czech Academy of Sciences Publication Activity Database

    Sehnal, František; Sutherland, T.

    2008-01-01

    Roč. 2, č. 4 (2008), s. 145-153 ISSN 1933-6896 R&D Projects: GA MŠk ME 907 Institutional research plan: CEZ:AV0Z50070508 Keywords : silk * proteinaceous polymers * alfa-helices Subject RIV: ED - Physiology Impact factor: 0.875, year: 2008 http://www.landesbioscience.com/journals/prion/article/7489

  14. Identification of circular RNA in the Bombyx mori silk gland.

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    Gan, Huaiyan; Feng, Tieshan; Wu, Yuqian; Liu, Chun; Xia, Qingyou; Cheng, Tingcai

    2017-10-01

    Bombyx mori is an economically important holometabolous lepidopteran insect. In B. mori endogenous noncoding RNAs such as microRNAs (miRNAs) and Piwi-interacting RNAs play crucial biological functions in metamorphosis and sex determination. In addition, circular RNAs (circRNAs) have been recently identified as noncoding RNAs in most common model organisms and show potential as gene regulators. However, to date, there have been few studies on the circRNAs present in the B. mori genome conducted to date. Here, we identified 3916 circRNAs by deep circular transcriptome sequencing using the silk gland of B. mori. 3155 circRNAs were found to be derived from 1727 parental genes. The circRNAs displayed tissue-specific expression between the middle silk gland (MSG) and posterior silk gland (PSG), with 2532 and 880 being upregulated circRNAs in the MSG and PSG, respectively. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that the parental genes from the MSG and PSG were generally annotated to similar categories and pathways. The interaction network of circRNAs and miRNAs showed that circRNAs might act as miRNA sponges or interact with miRNAs in some other way. Overall, the results revealed the complicated patterns of circRNAs in the B. mori silk gland providing a new angle from which to explore the mechanisms of complex gene regulation and efficient silk protein synthesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Proteome identification of the silkworm middle silk gland

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    Jian-ying Li

    2016-03-01

    Full Text Available To investigate the functional differentiation among the anterior (A, middle (M, and posterior (P regions of silkworm middle silk gland (MSG, their proteomes were characterized by shotgun LC–MS/MS analysis with a LTQ-Orbitrap mass spectrometer. To get better proteome identification and quantification, triplicate replicates of mass spectrometry analysis were performed for each sample. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium (Vizcaíno et al., 2014 [1] via the PRIDE partner repository (Vizcaino, 2013 [2] with the dataset identifier http://www.ebi.ac.uk/pride/archive/projects/PXD003371. The peptide identifications that were further processed by PeptideProphet program in Trans-Proteomic Pipeline (TPP after database search with Mascot software were also available in .XML format files. Data presented here are related to a research article published in Journal of Proteomics by Li et al. (2015 [3]. Keywords: Bombyx mori, Middle silk gland, Silk protein synthesis, Shotgun proteomics, Label-free

  16. The embryonic origin of the ampullate silk glands of the spider Cupiennius salei.

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    Hilbrant, Maarten; Damen, Wim G M

    2015-05-01

    Silk production in spiders is considered a key innovation, and to have been vital for the diversification of the clade. The evolutionary origin of the organs involved in spider silk production, however, and in particular of the silk glands, is poorly understood. Homologies have been proposed between these and other glands found in arachnids, but lacking knowledge of the embryonic development of spider silk glands hampers an evaluation of hypotheses. This study focuses on the embryonic origin of the largest silk glands of the spider Cupiennius salei, the major and minor ampullate glands. We show how the ampullate glands originate from ectodermal invaginations on the embryonic spinneret limb buds, in relation to morphogenesis of these buds. Moreover, we visualize the subsequent growth of the ampullate glands in sections of the early postembryonic stages. The invaginations are shown to correlate with expression of the proneural gene CsASH2, which is remarkable since it has been proposed that spider silk glands and their nozzles originate from sensory bristles. Hence, by confirming the ectodermal origin of spider silk glands, and by describing the (post-)embryonic morphogenesis of the ampullate glands, this work provides a starting point for further investigating into the genetic program that underlies their development. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. The effect of gamma irradiation on some morphological and quantitative changes of Bombyx mori L. silk gland; Vliyanie na gama lychite vyrhu nykoi morfologichni i kolichestveni izmeneniya na koprinenootdelitelnata zhleza na Bombyx mori L

    Energy Technology Data Exchange (ETDEWEB)

    Petkov, N; Malinova, K [Institute of Animal Breeding, Kostinbrod (Bulgaria); Binkh, N [National Centre of Sericulture, Hanoj (Viet Nam)

    1997-12-31

    A study to determine the effect of gamma irradiation of silkworm eggs at doses of 1.00; 2.00 and 3.00 on silk gland weight, length and width is performed. It was found that gamma irradiation of eggs in the stage of embryo most intensive growth in length (B{sub 2}) at doses 2.00 and 3.00 Gy stimulates increasing of silk glands weight in silkworms on the fifth day instar by 12-25 mg, as well as the silk worm width - by 7-33 {mu}m, which is of significant importance for the synthesis and secretion of silk proteins (fibroin and sericin). A breed specificity was also observed. 4 refs.

  18. Timing of autophagy and apoptosis during posterior silk gland degeneration in Bombyx mori.

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    Montali, Aurora; Romanelli, Davide; Cappellozza, Silvia; Grimaldi, Annalisa; de Eguileor, Magda; Tettamanti, Gianluca

    2017-07-01

    Over the years, the silkworm, Bombyx mori, has been manipulated by means of chemical and genetic approaches to improve silk production both quantitatively and qualitatively. The silk is produced by the silk gland, which degenerates quickly once the larva has finished spinning the cocoon. Thus, interfering with this degeneration process could help develop new technologies aimed at ameliorating silk yield. To this end, in this work we studied the cell death processes that lead to the demise of the posterior silk gland of B. mori, directing in particular our attention to autophagy and apoptosis. We focused on this portion of the gland because it produces fibroin, the main component of the silk thread. By using multiple markers, we provide a morphological, biochemical and molecular characterization of the apoptotic and autophagic processes and define their timing in this biological setting. Our data demonstrate that the activation of both autophagy and apoptosis is preceded by a transcriptional rise in key regulatory genes. Moreover, while autophagy is maintained active for several days and progressively digests silk gland cells, apoptosis is only switched on at a very late stage of silk gland demise. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Complex gene expression in the dragline silk producing glands of the Western black widow (Latrodectus hesperus).

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    Lane, Amanda Kelly; Hayashi, Cheryl Y; Whitworth, Gregg B; Ayoub, Nadia A

    2013-12-02

    Orb-web and cob-web weaving spiders spin dragline silk fibers that are among the strongest materials known. Draglines are primarily composed of MaSp1 and MaSp2, two spidroins (spider fibrous proteins) expressed in the major ampullate (MA) silk glands. Prior genetic studies of dragline silk have focused mostly on determining the sequence of these spidroins, leaving other genetic aspects of silk synthesis largely uncharacterized. Here, we used deep sequencing to profile gene expression patterns in the Western black widow, Latrodectus hesperus. We sequenced millions of 3'-anchored "tags" of cDNAs derived either from MA glands or control tissue (cephalothorax) mRNAs, then associated the tags with genes by compiling a reference database from our newly constructed normalized L. hesperus cDNA library and published L. hesperus sequences. We were able to determine transcript abundance and alternative polyadenylation of each of three loci encoding MaSp1. The ratio of MaSp1:MaSp2 transcripts varied between individuals, but on average was similar to the estimated ratio of MaSp1:MaSp2 in dragline fibers. We also identified transcription of TuSp1 in MA glands, another spidroin family member that encodes the primary component of egg-sac silk, synthesized in tubuliform glands. In addition to the spidroin paralogs, we identified 30 genes that are more abundantly represented in MA glands than cephalothoraxes and represent new candidates for involvement in spider silk synthesis. Modulating expression rates of MaSp1 variants as well as MaSp2 and TuSp1 could lead to differences in mechanical properties of dragline fibers. Many of the newly identified candidate genes likely encode secreted proteins, suggesting they could be incorporated into dragline fibers or assist in protein processing and fiber assembly. Our results demonstrate previously unrecognized transcript complexity in spider silk glands.

  20. Spider Transcriptomes Identify Ancient Large-Scale Gene Duplication Event Potentially Important in Silk Gland Evolution.

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    Clarke, Thomas H; Garb, Jessica E; Hayashi, Cheryl Y; Arensburger, Peter; Ayoub, Nadia A

    2015-06-08

    The evolution of specialized tissues with novel functions, such as the silk synthesizing glands in spiders, is likely an influential driver of adaptive success. Large-scale gene duplication events and subsequent paralog divergence are thought to be required for generating evolutionary novelty. Such an event has been proposed for spiders, but not tested. We de novo assembled transcriptomes from three cobweb weaving spider species. Based on phylogenetic analyses of gene families with representatives from each of the three species, we found numerous duplication events indicative of a whole genome or segmental duplication. We estimated the age of the gene duplications relative to several speciation events within spiders and arachnids and found that the duplications likely occurred after the divergence of scorpions (order Scorpionida) and spiders (order Araneae), but before the divergence of the spider suborders Mygalomorphae and Araneomorphae, near the evolutionary origin of spider silk glands. Transcripts that are expressed exclusively or primarily within black widow silk glands are more likely to have a paralog descended from the ancient duplication event and have elevated amino acid replacement rates compared with other transcripts. Thus, an ancient large-scale gene duplication event within the spider lineage was likely an important source of molecular novelty during the evolution of silk gland-specific expression. This duplication event may have provided genetic material for subsequent silk gland diversification in the true spiders (Araneomorphae). © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  1. Titanium dioxide nanoparticles relieve silk gland damage and increase cocooning of Bombyx mori under phoxim-induced toxicity.

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    Li, Bing; Yu, Xiaohong; Gui, Suxin; Xie, Yi; Hong, Jie; Zhao, Xiaoyang; Sheng, Lei; Sang, Xuezi; Sun, Qingqing; Wang, Ling; Shen, Weide; Hong, Fashui

    2013-12-18

    Organophosphate pesticides are applied widely in the world for agricultural purposes, and their exposures often resulted in non-cocooning of Bombyx mori in China. TiO2 nanoparticles have been demonstrated to increase pesticide resistance of Bombyx mori. While the toxicity of phoxim is well-documented, very limited information exists on the mechanisms of TiO2 nanoparticles improving the cocooning function of Bombyx mori following exposure to phoxim. The present study was, therefore, undertaken to determine whether TiO2 nanoparticles attenuate silk gland injury and elevate cocooning of B. mori following exposure to phoxim. The findings suggested that phoxim exposure resulted in severe damages of the silk gland structure and significantly decreased the cocooning in the silk gland of Bombyx mori. Furthermore, phoxim exposure significantly resulted in reductions of total protein concentrations and suppressed expressions of silk protein synthesis-related genes, including Fib-L, Fib-H, P25, Ser-2, and Ser-3, in the silk gland. TiO2 nanoparticle pretreatment, however, could significantly relieve silk gland injury of Bombyx mori. Importantly, TiO2 nanoparticles could remarkably elevate cocooning and total protein contents and promote expressions of Fib-L, Fib-H, P25, Ser-2, and Ser-3 in the silk gland following exposure to phoxim.

  2. Review structure of silk by raman spectromicroscopy: from the spinning glands to the fibers.

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    Lefèvre, Thierry; Paquet-Mercier, François; Rioux-Dubé, Jean-François; Pézolet, Michel

    2012-06-01

    Raman spectroscopy has long been proved to be a useful tool to study the conformation of protein-based materials such as silk. Thanks to recent developments, linearly polarized Raman spectromicroscopy has appeared very efficient to characterize the molecular structure of native single silk fibers and spinning dopes because it can provide information relative to the protein secondary structure, molecular orientation, and amino acid composition. This review will describe recent advances in the study of the structure of silk by Raman spectromicroscopy. A particular emphasis is put on the spider dragline and silkworm cocoon threads, other fibers spun by orb-weaving spiders, the spinning dope contained in their silk glands and the effect of mechanical deformation. Taken together, the results of the literature show that Raman spectromicroscopy is particularly efficient to investigate all aspects of silk structure and production. The data provided can lead to a better understanding of the structure of the silk dope, transformations occurring during the spinning process, and structure and mechanical properties of native fibers. Copyright © 2011 Wiley Periodicals, Inc.

  3. Hunting with sticky tape: functional shift in silk glands of araneophagous ground spiders (Gnaphosidae).

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    Wolff, Jonas O; Řezáč, Milan; Krejčí, Tomáš; Gorb, Stanislav N

    2017-06-15

    Foraging is one of the main evolutionary driving forces shaping the phenotype of organisms. In predators, a significant, though understudied, cost of foraging is the risk of being injured by struggling prey. Hunting spiders that feed on dangerous prey like ants or other spiders are an extreme example of dangerous feeding, risking their own life over a meal. Here, we describe an intriguing example of the use of attachment silk (piriform silk) for prey immobilization that comes with the costs of reduced silk anchorage function, increased piriform silk production and additional modifications of the extrusion structures (spigots) to prevent their clogging. We show that the piriform silk of gnaphosids is very stretchy and tough, which is an outstanding feat for a functional glue. This is gained by the combination of an elastic central fibre and a bi-layered glue coat consisting of aligned nanofibrils. This represents the first tensile test data on the ubiquitous piriform gland silk, adding an important puzzle piece to the mechanical catalogue of silken products in spiders. © 2017. Published by The Company of Biologists Ltd.

  4. Sequential steps of macroautophagy and chaperone-mediated autophagy are involved in the irreversible process of posterior silk gland histolysis during metamorphosis of Bombyx mori.

    Science.gov (United States)

    Shiba, Hajime; Yabu, Takeshi; Sudayama, Makoto; Mano, Nobuhiro; Arai, Naoto; Nakanishi, Teruyuki; Hosono, Kuniaki

    2016-04-15

    To elucidate the degradation process of the posterior silk gland during metamorphosis of the silkworm ITALIC! Bombyx mori, tissues collected on the 6th day after entering the 5th instar (V6), prior to spinning (PS), during spinning (SP) and after cocoon formation (CO) were used to analyze macroautophagy, chaperone-mediated autophagy (CMA) and the adenosine triphosphate (ATP)-dependent ubiquitin proteasome. Immediately after entering metamorphosis stage PS, the levels of ATP and phosphorylated p70S6 kinase protein decreased spontaneously and continued to decline at SP, followed by a notable restoration at CO. In contrast, phosphorylated AMP-activated protein kinase α (AMPKα) showed increases at SP and CO. Most of the Atg8 protein was converted to form II at all stages. The levels of ubiquitinated proteins were high at SP and CO, and low at PS. The proteasome activity was high at V6 and PS but low at SP and CO. In the isolated lysosome fractions, levels of Hsc70/Hsp70 protein began to increase at PS and continued to rise at SP and CO. The lysosomal cathepsin B/L activity showed a dramatic increase at CO. Our results clearly demonstrate that macroautophagy occurs before entering the metamorphosis stage and strongly suggest that the CMA pathway may play an important role in the histolysis of the posterior silk gland during metamorphosis. © 2016. Published by The Company of Biologists Ltd.

  5. Purification and some properties of G-factor from the silk gland of silkworm

    Energy Technology Data Exchange (ETDEWEB)

    Taira, H; Ejiri, S I; Shimura, K [Tohoku Univ., Sendai (Japan). Faculty of Agriculture

    1972-12-01

    Purification of G-factor from the silk gland of silkworms and some of its properties have been studied in comparison with the G-factor from E. coli and rat liver transferase II. In the experiment, GTP-..gamma..-/sup 32/P was prepared from GDP and /sup 32/Pi by photophosphorylation with spinach chloroplasts, and purified by Dowex-1 chromatography. The purified G-factor was homogeneous on disc gel electrophoresis. Molecular weight of 80,000 was estimated from a calibrated Sephadex G-200 column. The purified G-factor exhibited uncoupled ribosome-dependent GTPase activity, and was inhibited by fusidic acid, SH inhibitor, and diphtheria toxin plus NAD. The G-factor from E. coli and that from the silk gland were not interchangeable in GTPase reaction.

  6. Purification and some properties of G-factor from the silk gland of silkworm

    International Nuclear Information System (INIS)

    Taira, Hideharu; Ejiri, Shin-ichiro; Shimura, Kensuke

    1972-01-01

    Purification of G-factor from the silk gland of silkworms and some of its properties have been studied in comparison with the G-factor from E. coli and rat liver transferase II. In the experiment, GTP-γ- 32 P was prepared from GDP and 32 Pi by photophosphorylation with spinach chloroplasts, and purified by Dowex-1 chromatography. The purified G-factor was homogeneous on disc gel electrophoresis. Molecular weight of 80,000 was estimated from a calibrated Sephadex G-200 column. The purified G-factor exhibited uncoupled ribosome-dependent GTPase activity, and was inhibited by fusidic acid, SH inhibitor, and diphtheria toxin plus NAD. The G-factor from E. coli and that from the silk gland were not interchangeable in GTPase reaction. (Yamanoto, Y.)

  7. Proteome analysis of gut and salivary gland proteins of fifth-instar nymph and adults of the sunn pest, Eurygaster integriceps.

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    Bezdi, Mohammad Saadati; Toorchi, Mahmoud; Pourabad, Reza Farshbaf; Zarghami, Nosratollah; Nouri, Mohammad-Zaman; Komatsu, Setsuko

    2012-10-01

    In the digestive system of the sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), the salivary gland has a key role in extra oral digestion and the gut is the main site for digestion of food. In this study, proteomics was used to study the role of proteins involved in digestion. The amount of feeding on wheat grain by adult insects increased by comparison to fifth-instar nymphs. Proteins of the gut and salivary gland in adults and fifth-instar nymphs were analyzed 1 day after feeding. The proteins related to digestion, metabolism, and defense against toxins were accumulated in the gut of adult insects. Three plant proteins including serpin, dehydroascorbate reductase, and β-amylase were accumulated in guts of adults. In the salivary gland, phospholipase A2 and arginine kinase were increased in adults. Heat shock protein 70 increased in the gut of fifth-instar nymphs. Proteomic analysis revealed that most of changed proteins in digestive system of sunn pest were increased in adults. This study provided more targets derived from gut and salivary gland for pest management. © 2012 Wiley Periodicals, Inc.

  8. A histochemical study of the posterior silk glands of Bombyx mori during metamorphosis from larvae to pupae using frozen sections.

    Science.gov (United States)

    Kawamoto, K; Kawamoto, T; Shiba, H; Hosono, K

    2014-02-01

    The fine structures of the whole bodies and the posterior silk glands of Bombyx mori during metamorphosis from larvae to pupae in the cocoon were preserved virtually without damage when frozen sections were prepared using an adhesive plastic film. We used frozen sections for histochemical and enzyme histochemistry to characterize the metamorphosis of the posterior silk glands. Frozen sections were stained with DAPI to observe nuclear changes, examined using the TUNEL method to detect DNA fragments, and investigated using in situ hybridization to detect B. mori caspase expression. Both DNA fragments and expression of B. mori caspase increased with progressing metamorphosis. The degeneration of the posterior silk gland during metamorphosis appears to be an apoptotic event.

  9. DNA Synthesis during Endomitosis Is Stimulated by Insulin via the PI3K/Akt and TOR Signaling Pathways in the Silk Gland Cells of Bombyx mori

    Directory of Open Access Journals (Sweden)

    Yaofeng Li

    2015-03-01

    Full Text Available Silk gland cells undergo multiple endomitotic cell cycles during silkworm larval ontogeny. Our previous study demonstrated that feeding is required for continued endomitosis in the silk gland cells of silkworm larvae. Furthermore, the insulin signaling pathway is closely related to nutritional signals. To investigate whether the insulin signaling pathway is involved in endomitosis in silk gland cells, in this study, we initially analyzed the effects of bovine insulin on DNA synthesis in endomitotic silk gland cells using 5-bromo-2'-deoxyuridine (BrdU labeling technology, and found that bovine insulin can stimulate DNA synthesis. Insulin signal transduction is mainly mediated via phosphoinositide 3-kinase (PI3K/Akt, the target of rapamycin (TOR and the extracellular signal-regulated kinase (ERK pathways in vertebrates. We ascertained that these three pathways are involved in DNA synthesis in endomitotic silk gland cells using specific inhibitors against each pathway. Moreover, we investigated whether these three pathways are involved in insulin-stimulated DNA synthesis in endomitotic silk gland cells, and found that the PI3K/Akt and TOR pathways, but not the ERK pathway, are involved in this process. These results provide an important theoretical foundation for the further investigations of the mechanism underlying efficient endomitosis in silk gland cells.

  10. Molecular mechanisms of phoxim-induced silk gland damage and TiO2 nanoparticle-attenuated damage in Bombyx mori.

    Science.gov (United States)

    Li, Bing; Yu, Xiaohong; Gui, Suxin; Xie, Yi; Zhao, Xiaoyang; Hong, Jie; Sun, Qingqing; Sang, Xuezi; Sheng, Lei; Cheng, Zhe; Cheng, Jie; Hu, Rengping; Wang, Ling; Shen, Weide; Hong, Fashui

    2014-06-01

    Phoxim is a useful organophosphate (OP) pesticide used in agriculture in China, however, exposure to this pesticide can result in a significant reduction in cocooning in Bombyx mori (B. mori). Titanium dioxide nanoparticles (TiO2 NPs) have been shown to decrease phoxim-induced toxicity in B. mori; however, very little is known about the molecular mechanisms of silk gland damage due to OP exposure and repair of gland damage by TiO2 NP pretreatment. In the present study, exposure to phoxim resulted in a significant reduction in cocooning rate in addition to silk gland damage, whereas TiO2 NP attenuated phoxim-induced gland damage, increased the antioxidant capacity of the gland, and increased cocooning rate in B. mori. Furthermore, digital gene expression data suggested that phoxim exposure led to significant alterations in the expression of 833 genes. In particular, phoxim exposure caused significant down-regulation of Fib-L, Ser2, Ser3, and P25 genes involved in silk protein synthesis, and up-regulation of SFGH, UCH3, and Salhh genes involved in silk protein hydrolysis. A combination of both phoxim and TiO2 NP treatment resulted in marked changes in the expression of 754 genes, while treatment with TiO2 NPs led to significant alterations in the expression of 308 genes. Importantly, pretreatment with TiO2 NPs increased Fib-L, Ser2, Ser3, and P25 expression, and decreased SFGH, UCH3, and Salhh expression in silk protein in the silk gland under phoxim stress. Therefore, Fib-L, Ser2, Ser3, P25, SFGH, UCH3, and Salhh may be potential biomarkers of silk gland toxicity in B. mori caused by phoxim exposure. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Spider Silk: From Protein-Rich Gland Fluids to Diverse Biopolymer Fibers

    Science.gov (United States)

    2016-01-06

    properties from tougher than Kevlar to the extensibility of rubber and have the potential for numerous military applications ranging from high... infrared (FT- Figure 7. 31P DD-MAS and CP-MAS NMR spectra on native, hydrated (A, B), EDTA-treated (C, D) and CaCl2-treated (E, F) caddisfly silk

  12. Invited review the coiled coil silk of bees, ants, and hornets.

    Science.gov (United States)

    Sutherland, Tara D; Weisman, Sarah; Walker, Andrew A; Mudie, Stephen T

    2012-06-01

    In this article, we review current knowledge about the silk produced by the larvae of bees, ants, and hornets [Apoidea and Vespoidea: Hymenoptera]. Different species use the silk either alone or in composites for a variety of purposes including mechanical reinforcement, thermal regulation, or humidification. The characteristic molecular structure of this silk is α-helical proteins assembled into tetrameric coiled coils. Gene sequences from seven species are available, and each species possesses a copy of each of four related silk genes that encode proteins predicted to form coiled coils. The proteins are ordered at multiple length scales within the labial gland of the final larval instar before spinning. The insects control the morphology of the silk during spinning to produce either fibers or sheets. The silk proteins are small and non repetitive and have been produced artificially at high levels by fermentation in E. coli. The artificial silk proteins can be fabricated into materials with structural and mechanical properties similar to those of native silks. Copyright © 2011 Wiley Periodicals, Inc.

  13. High-efficiency production of human serum albumin in the posterior silk glands of transgenic silkworms, Bombyx mori L.

    Directory of Open Access Journals (Sweden)

    Qiujie Qian

    Full Text Available Human serum albumin (HSA is an important biological preparation with a variety of biological functions in clinical applications. In this study, the mRNA of a fusion transposase derived from the pESNT-PBase plasmid and a pBHSA plasmid containing the HSA gene under the control of a fibroin light chain (FL promoter were co-injected into fertilized eggs. Fifty-six transgenic silkworm pedigrees expressing theexogenous recombinant HSA (rHSA in the posterior silk glands (PSGs with stable inheritance were successfully obtained. The SDS-PAGE and Western blot results confirmed that the rHSA was secreted into the transgenic silkworm cocoon, and the rHSA could be easily extracted with phosphate-buffered saline (PBS. In our research, the isolated highest amount rHSA constituted up to 29.1% of the total soluble protein of the cocoon shell, indicating that the transgenic silkworm produced an average of 17.4 μg/mg of rHSA in the cocoon shell. The production of soluble rHSA in the PSGs by means of generating transgenic silkworms is a novel approach, whereby a large amount of virus-free and functional HSA can be produced through the simple rearing of silkworms.

  14. In vivo NMR analysis of incorporation of [2-13C] glycine into silk fibroin

    International Nuclear Information System (INIS)

    Asakura, Tetsuo; Nagashima, Mariko; Demura, Makoto; Osanai, Minoru.

    1990-01-01

    The biosynthetic mechanism of silk fibroin in silkworms, Bombyx mori, is unique because this fibrous protein composed mainly of glycine, alanine and serine is produced very rapidly in large quantity in the posterior silk glands. It is very meaningful to investigate into the biosynthesis of silk protein under nondestructive condition by in vivo NMR and C-13 labeling techniques. The sugar metabolism related to the production of silk fibroin was analyzed by monitoring the change in the C-13 labeled peaks in the NMR spectra for silkworms. In this paper, the monitoring of the 2-(C-13) glycine metabolism in Bombyx mori by the C-13 NMR in vivo is reported. In particular, the in vivo transport of glycine from the midgut to the posterior silk gland was measured, and the rate constants were determined with the course of the peak intensity in the C-13 NMR spectra. It is possible to discuss quantitatively the in vivo production of silk fibroin with these rate constants. The experiment and the results are reported. The in vivo C-13 NMR spectra of a 5 day old, 5th instar larva of Bombyx mori after the oral administration of 2-(C-13) glycine are shown. The significant increase of the peak intensity occurred. (K.I.)

  15. SPIDER SILK

    Directory of Open Access Journals (Sweden)

    PORAV Viorica

    2014-05-01

    Full Text Available The strengthness and toughness of spider fiber and its multifunctional nature is only surpassed in some cases by synthetic high performance fibers. In the world of natural fibers, spider silk has been long time recognized as a wonder fiber for its unique combination of high strength and rupture elongation. Scientists in civil military engineering reveal that the power of biological material (spider silk lies in the geometric configuration of structural protein, and the small cluster of week hydrogen bonds that works together to resist force and dissipate energy. Each spider and each type of silk has a set of mechanical properties optimized for their biological function. Most silks, in particular deagline silk, have exceptional mechanical properties. They exhibit a unique combination of high tensile strength and extensibility (ductility. This enables a silk fiber to absorb a lot of energy before breaking (toughness, the area under a stress- strain curve. A frequent mistake made in the mainstream media is to confuse strength and toughness when comparing silk to other materials. As shown below in detail, weight for weight, silk is stronger than steel, but not as strong as Kevlar. Silk is,however, tougher than both.This paper inform about overview on the today trend in the world of spider silk.

  16. Silk fibers and silk-producing organs of Harpactea rubicunda (C. L. Koch 1838) (Araneae, Dysderidae).

    Science.gov (United States)

    Hajer, Jaromír; Malý, Jan; Reháková, Dana

    2013-01-01

    Scanning electron microscopy and atomic force microscopy were used to study the silk spinning apparatus and silks of Harpactea rubicunda spiders. Three types of silk secretions that are produced by three kinds of silk spinning glands (ampullate, piriform, and pseudaciniform) and released through three types of spigots, were confirmed for both adult and juvenile spiders. Silk secretions for the construction of spider webs for shelter or retreat are produced by the pseudaciniform silk glands. Silk secretions that are released from spigots in the course of web construction are not processed by the legs during the subsequent process of hardening. Pairs of nanofibril bundles seemed to be part of the basic microarchitecture of the web silk fibers as revealed by AFM. These fiber bundles frequently not only overlap one another, but occasionally also interweave. This structural variability may strengthen the spider web. High-resolution AFM scans of individual nanofibrils show a distinctly segmented nanostructure. Each globular segment is ∼30-40 nm long along the longitudinal axis of the fiber, and resembles a nanosegment of artificial fibroin described by Perez-Rigueiro et al. (2007). Copyright © 2012 Wiley Periodicals, Inc.

  17. On-plant movement and feeding of western bean cutworm (Lepidoptera: Noctuidae) early instars on corn.

    Science.gov (United States)

    Paula-Moraes, S V; Hunt, T E; Wright, R J; Hein, G L; Blankenship, E E

    2012-12-01

    Western bean cutworm, Striacosta albicosta (Smith), has undergone a recent eastward expansion from the western U.S. Corn Belt to Pennsylvania and parts of Canada. Little is known about its ecology and behavior, particularly during the early instars, on corn (Zea mays L.). There is a narrow treatment window for larvae, and early detection of the pest in the field is essential. An understanding of western bean cutworm larval feeding and early-instar dispersal is essential to understand larval survival and establishment in corn. Studies were conducted in 2009 through 2011 in Nebraska to determine the feeding and dispersal of early-instar western bean cutworm on corn. The treatment design was a factorial with three corn stages (pretassel, tassel, and posttassel) and five corn plant zones (tassel, above ear, primary ear, secondary ear, and below ear) in a randomized complete block design. The effects of different corn tissues on larval survival and development were investigated in laboratory studies in a randomized complete block design during 2009 and 2011. Treatments were different corn tissues (leaf alone, leaf with developing tassel, pollen, pollen plus silk, and silk alone). Results demonstrated that neonate larvae move to the upper part of the plant, independent of corn stage. Larval growth was optimal when fed on tassel tissue. Overall results indicated a selective benefit for movement of the early instar to upper part of the plant.

  18. Silk Spinning in Silkworms and Spiders.

    Science.gov (United States)

    Andersson, Marlene; Johansson, Jan; Rising, Anna

    2016-08-09

    Spiders and silkworms spin silks that outcompete the toughness of all natural and manmade fibers. Herein, we compare and contrast the spinning of silk in silkworms and spiders, with the aim of identifying features that are important for fiber formation. Although spiders and silkworms are very distantly related, some features of spinning silk seem to be universal. Both spiders and silkworms produce large silk proteins that are highly repetitive and extremely soluble at high pH, likely due to the globular terminal domains that flank an intermediate repetitive region. The silk proteins are produced and stored at a very high concentration in glands, and then transported along a narrowing tube in which they change conformation in response primarily to a pH gradient generated by carbonic anhydrase and proton pumps, as well as to ions and shear forces. The silk proteins thereby convert from random coil and alpha helical soluble conformations to beta sheet fibers. We suggest that factors that need to be optimized for successful production of artificial silk proteins capable of forming tough fibers include protein solubility, pH sensitivity, and preservation of natively folded proteins throughout the purification and initial spinning processes.

  19. Improved strength of silk fibers in Bombyx mori trimolters induced by an anti-juvenile hormone compound.

    Science.gov (United States)

    Guo, Kaiyu; Dong, Zhaoming; Zhang, Yan; Wang, Dandan; Tang, Muya; Zhang, Xiaolu; Xia, Qingyou; Zhao, Ping

    2018-05-01

    Bombyx mori silk fibers with thin diameters have advantages of lightness and crease-resistance. Many studies have used anti-juvenile hormones to induce trimolters in order to generate thin silk; however, there has been comparatively little analysis of the morphology, structure and mechanical properties of trimolter silk. This study induced two kinds of trimolters by appling topically anti-juvenile hormones and obtained thin diameter silk. Scanning electron microscope (SEM), FTIR analysis, tensile mechanical testing, chitin staining were used to reveal that the morphology, conformation and mechanical property of the trimolter silk. Cocoon of trimolters were highly densely packed by thinner fibers and thus had small apertures. We found that the conformation of trimolter silk fibroin changed and formed more β-sheet structures. In addition, analysis of mechanical parameters yielded a higher Young's modulus and strength in trimolter silk than in the control. By chitin staining of silk gland, we postulated that the mechanical properties of trimolters' silk was enhanced greatly during to the structural changes of silk gland. We induced trimolters by anti-juvenile hormones and the resulting cocoons were more closely packed and had smaller silk fiber diameters. We found that the conformation of trimolters silk fibroin had a higher content of β-sheet structures and better mechanical properties. Our study revealed the structures and mechanical properties of trimolter silk, and provided a valuable reference to improve silk quality by influencing molting in silkworms. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Self-assembly of silk fibroin under osmotic stress

    Science.gov (United States)

    Sohn, Sungkyun

    The supramolecular self-assembly behavior of silk fibroin was investigated using osmotic stress technique. In Chapter 2, a ternary phase diagram of water-silk-LiBr was constructed based on X-ray results on the osmotically stressed regenerated silk fibroin of Bombyx mori silkworm. Microscopic data indicated that silk I is a hydrated structure and a rough estimate of the number of water molecules lost by the structure upon converting from silk I to silk II has been made, and found to be about 2.2 per [GAGAGS] hexapeptide. In Chapter 3, wet-spinning of osmotically stressed, regenerated silk fibroin was performed, based on the prediction that the enhanced control over structure and phase behavior using osmotic stress method helps improve the physical properties of wet-spun regenerated silk fibroin fibers. The osmotic stress was applied in order to pre-structure the regenerated silk fibroin molecule from its original random coil state to more oriented state, manipulating the phase of the silk solution in the phase diagram before the start of spinning. Monofilament fiber with a diameter of 20 microm was produced. In Chapter 4, we investigated if there is a noticeable synergistic osmotic pressure increase between co-existing polymeric osmolyte and salt when extremely highly concentrated salt molecules are present both at sample subphase and stressing subphase, as is the case of silk fibroin self-assembly. The equilibration method that measures osmotic pressure relative to a reference with known osmotic pressure was introduced. Osmotic pressure of aqueous LiBr solution up to 2.75M was measured and it was found that the synergistic effect was insignificant up to this salt concentration. Solution parameters of stressing solutions and Arrhenius kinetics based on time-temperature relationship for the equilibration process were derived as well. In Chapter 5, self-assembly behavior of natural silk fibroin within the gland of Bombyx mori silkworm was investigated using osmotic

  1. Effects of silk fibroin in murine dry eye

    Science.gov (United States)

    Kim, Chae Eun; Lee, Ji Hyun; Yeon, Yeung Kyu; Park, Chan Hum; Yang, Jaewook

    2017-03-01

    The study aimed to investigate the effects of silk fibroin in a mouse model of dry eye. The experimental dry eye mouse model was developed using more than twelve-weeks-old NOD.B10.H2b mice exposing them to 30-40% ambient humidity and injecting them with scopolamine hydrobromide for 10 days. Tear production and corneal irregularity score were measured by the instillation of phosphate buffered saline or silk fibroin. Corneal detachment and conjunctival goblet cell density were observed by hematoxylin and eosin or periodic acid Schiff staining in the cornea or conjunctiva. The expression of inflammatory markers was detected by immunohistochemistry in the lacrimal gland. The silk group tear production was increased, and corneal smoothness was improved. The corneal epithelial cells and conjunctival goblet cells were recovered in the silk groups. The expression of inflammatory factors was inhibited in the lacrimal gland of the silk group. These results show that silk fibroin improved the cornea, conjunctiva, and lacrimal gland in the mouse model of dry eye. These findings suggest that silk fibroin has anti-inflammatory effects in the experimental models of dry eye.

  2. Silk elasticity as a potential constraint on spider body size.

    Science.gov (United States)

    Rodríguez-Gironés, Miguel A; Corcobado, Guadalupe; Moya-Laraño, Jordi

    2010-10-07

    Silk is known for its strength and extensibility and has played a key role in the radiation of spiders. Individual spiders use different glands to produce silk types with unique sets of proteins. Most research has studied the properties of major ampullate and capture spiral silks and their ecological implications, while little is known about minor ampullate silk, the type used by those spider species studied to date for bridging displacements. A biomechanical model parameterised with available data shows that the minimum radius of silk filaments required for efficient bridging grows with the square root of the spider's body mass, faster than the radius of minor ampullate silk filaments actually produced by spiders. Because the morphology of spiders adapted to walking along or under silk threads is ill suited for moving on a solid surface, for these species there is a negative relationship between body mass and displacement ability. As it stands, the model suggests that spiders that use silk for their displacements are prevented from attaining a large body size if they must track their resources in space. In particular, silk elasticity would favour sexual size dimorphism because males that must use bridging lines to search for females cannot grow large. 2010 Elsevier Ltd. All rights reserved.

  3. Instar and outstar learning with memristive nanodevices

    International Nuclear Information System (INIS)

    Snider, Greg

    2011-01-01

    The instar and outstar synaptic models are among the oldest and most useful in the field of neural networks. In this paper we show how to approximate the behavior of instar and outstar synapses in neuromorphic electronic systems using memristive nanodevices and spiking neurons. Memristive nanodevices are especially attractive for this application since such devices are tiny, can be densely packed in crossbar-like structures and possess the long time constants, or memory, needed by the synaptic models.

  4. Transgenic Silk Moths to Produce Spider Silk

    National Research Council Canada - National Science Library

    Herrera, Rene J

    2008-01-01

    .... Other alternatives like production of the protein that yields same or similar mechanical properties of dragline silk in microorganisms or mammalian cells, in spinning fibers from concentrated protein...

  5. Biomechanics of Spider Silks

    Science.gov (United States)

    2006-03-02

    water and deformation conditions. Such fibres [Nexia ’ biosteel ’ silk ] were spun from recombinant silk ’cloned’ from Spidroin II and indeed show 67...SUBTITLE 5. FUNDING NUMBERS Biomechanics of Spider Silks F49620-03-1-0111 6. AUTHOR(S) Fritz Vollrath 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...Perform Pro, WHSIDIOR, Oct 94 COVER SHEET FINAL (3rd Year) Report to AFOSR on: BIOMECHANICS OF SPIDER SILKS Fritz Vollrath, Oxford University, England

  6. Radiation degradation of silk

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Kazushige; Kamiishi, Youichi [Textile Research Institute of Gunma, Kiryu, Gunma (Japan); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Silk fibroin powder was prepared from irradiated silk fibroin fiber by means of only physical treatment. Silk fibroin fiber irradiated with an accelerated electron beam in the dose range of 250 - 1000 kGy was pulverized by using a ball mill. Unirradiated silk fibroin fiber was not pulverized at all. But the more irradiation was increased, the more the conversion efficiency from fiber to powder was increased. The conversion efficiency of silk fibroin fiber irradiated 1000 kGy in oxygen was 94%. Silk fibroin powder shows remarkable solubility, which dissolved 57% into water of ambient temperature. It is a very interesting phenomenon that silk fibroin which did not treat with chemicals gets solubility only being pulverized. In order to study mechanism of solubilization of silk fibroin powder, amino acid component of soluble part of silk fibroin powder was analyzed. The more irradiation dose up, the more glycine or alanine degraded, but degradation fraction reached bounds about 50%. Other amino acids were degraded only 20% even at the maximum. To consider crystal construction of silk fibroin, it is suggested that irradiation on silk fibroin fiber selectively degrades glycine and alanine in amorphous region, which makes it possible to pulverize and to dissolve silk fibroin powder. (author)

  7. Early events in the evolution of spider silk genes.

    Directory of Open Access Journals (Sweden)

    James Starrett

    Full Text Available 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

  8. New application of silk protein

    International Nuclear Information System (INIS)

    Kamiishi, Youichi

    2000-01-01

    Gunma prefecture is famous for sericulture and silk textile industry district in Japan. In Gunma prefecture, some kinds of new generation silk as high performance and high quality silk were developed. These silk are used not only for the new textile materials but also for new industrial materials. New application of silk protein, fibroin and sericin, is considered. (author)

  9. New application of silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Kamiishi, Youichi [Textile Research Institute of Gunma, Kiryu, Gunma (Japan)

    2000-03-01

    Gunma prefecture is famous for sericulture and silk textile industry district in Japan. In Gunma prefecture, some kinds of new generation silk as high performance and high quality silk were developed. These silk are used not only for the new textile materials but also for new industrial materials. New application of silk protein, fibroin and sericin, is considered. (author)

  10. Comparative Study of Silk-Silk Alloy Materials

    Science.gov (United States)

    Xue, Ye; Jao, Dave; Hu, Wenbing; Wolf, Nathan; Rocks, Eva-Marie; Hu, Xiao

    Silk fibroin materials can be used for various kinds of biomedical applications. We report a comparative study of silk-silk blend materials using thermal analysis and infrared spectroscopy. Four groups of silk-silk blend films: Mori-Tussah, Mori-Muga, Mori-Eri and Mori-Thai, were fabricated from aqueous solutions and blended at different weight ratios, respectively. These silk-silk blend systems exploit the beneficial material properties of both silks. DSC and temperature-modulated DSC were used to measure the transition temperatures and heat capacity of these water-based silk-silk blend films. Fourier transform infrared spectrometer was used to characterize secondary structures of silk-silk blends. This study demonstrates that Mori silk are fully miscible with Tussah, Muga, Eri and Thai silk at different weight ratios without phase separation. Glass transition temperatures, degradation temperatures and the contents of alpha-helix and random coils of those silk-silk blend films can be controlled by changing the contents of different silks in the blend system. The features of Mori silk combined with the attributes of Tussah, Muga, Eri and Thai silk offer a useful suite of materials for a variety of applications in the future.

  11. Native Silk Feedstock as a Model Biopolymer: A Rheological Perspective.

    Science.gov (United States)

    Laity, Peter R; Holland, Chris

    2016-08-08

    Variability in silk's rheology is often regarded as an impediment to understanding or successfully copying the natural spinning process. We have previously reported such variability in unspun native silk extracted straight from the gland of the domesticated silkworm Bombyx mori and discounted classical explanations such as differences in molecular weight and concentration. We now report that variability in oscillatory measurements can be reduced onto a simple master-curve through normalizing with respect to the crossover. This remarkable result suggests that differences between silk feedstocks are rheologically simple and not as complex as originally thought. By comparison, solutions of poly(ethylene-oxide) and hydroxypropyl-methyl-cellulose showed similar normalization behavior; however, the resulting curves were broader than for silk, suggesting greater polydispersity in the (semi)synthetic materials. Thus, we conclude Nature may in fact produce polymer feedstocks that are more consistent than typical man-made counterparts as a model for future rheological investigations.

  12. Silk-microfluidics for advanced biotechnological applications: A progressive review.

    Science.gov (United States)

    Konwarh, Rocktotpal; Gupta, Prerak; Mandal, Biman B

    2016-01-01

    Silk based biomaterials have not only carved a unique niche in the domain of regenerative medicine but new avenues are also being explored for lab-on-a-chip applications. It is pertinent to note that biospinning of silk represents nature's signature microfluidic-maneuver. Elucidation of non-Newtonian flow of silk in the glands of spiders and silkworms has inspired researchers to fabricate devices for continuous extrusion and concentration of silk. Microfluidic channel networks within porous silk scaffolds ensure optimal nutrient and oxygen supply apart from serving as precursors for vascularization in tissue engineering applications. On the other hand, unique topographical features and surface wettability of natural silk fibers have inspired development of a number of simple and cost-effective devices for applications like blood typing and chemical sensing. This review mirrors the recent progress and challenges in the domain of silk-microfluidics for prospective avant-garde applications in the realm of biotechnology. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Morphometric analysis of instar variation in Tenebrio molitor (Coleoptera: Tenebrionidae)

    Science.gov (United States)

    Measurements of head capsule, mandible, metanotum, and body weight were done on larvae of Tenebrio molitor L. (Coleoptera: Tenebrionide) from the second to the last instar. Instar number varied from 14 to 18, but 15 or 16 instars were the most common. The value of dimensional measurements was evalua...

  14. Defensive responses by a social caterpillar are tailored to different predators and change with larval instar and group size

    Science.gov (United States)

    McClure, Melanie; Despland, Emma

    2011-05-01

    Gregariousness in animals is widely accepted as a behavioral adaptation for protection from predation. However, predation risk and the effectiveness of a prey's defense can be a function of several other factors, including predator species and prey size or age. The objective of this study was to determine if the gregarious habit of Malacosoma disstria caterpillars is advantageous against invertebrate natural enemies, and whether it is through dilution or cooperative defenses. We also examined the effects of larval growth and group size on the rate and success of attacks. Caterpillars of M. disstria responded with predator-specific behaviors, which led to increased survival. Evasive behaviors were used against stinkbugs, while thrashing by fourth instar caterpillars and holding on to the silk mat by second instar caterpillars was most efficient against spider attacks. Collective head flicking and biting by groups of both second and fourth instar caterpillars were observed when attacked by parasitoids. Increased larval size decreased the average number of attacks by spiders but increased the number of attacks by both stinkbugs and parasitoids. However, increased body size decreased the success rate of attacks by all three natural enemies and increased handling time for both predators. Larger group sizes did not influence the number of attacks from predators but increased the number of attacks and the number of successful attacks from parasitoids. In all cases, individual risk was lower in larger groups. Caterpillars showed collective defenses against parasitoids but not against the walking predators. These results show that caterpillars use different tactics against different natural enemies. Overall, these tactics are both more diverse and more effective in fourth instar than in second instar caterpillars, confirming that growth reduces predation risk. We also show that grouping benefits caterpillars through dilution of risk, and, in the case of parasitoids, through

  15. Effect of polyamines on mechanical and structural properties of Bombyx mori silk.

    Science.gov (United States)

    Yerra, Aparna; Mysarla, Danti Kumari; Siripurapu, Prasanthi; Jha, Anjali; Valluri, Satyavathi V; Mamillapalli, Anitha

    2017-01-01

    Silkworm, Bombyx mori (B. mori) belongs to the Lepidoptera family. The silk produced from this insect, mulberry silk, gained lot of importance as a fabric. Silk is being exploited as a biomaterial due to its surprising strength and biocompatibility. Polyamines (PA) are important cell growth regulators. In the present work the effect of treatment of polyamines, putrescine (Put), spermidine (Spd), and spermine (Spm) on the quantity and quality of silk produced was assessed. Results showed that exogenous feeding of Spd at a concentration of 50 µM increased fiber length significantly. Analysis by Fourier transform infrared (FTIR) on the properties of silk obtained from Spd treated silkworms revealed an increase in percentage of absorption with no difference in peak positions of amide I and amide III groups. Scanning electron microscopy (SEM) revealed an increase in diameter of silk. Further, analysis at molecular level showed an increase in fibroin expression in Spd treated silk glands. However, the Spd treatment showed no significant difference with respect to fibroin to sericin ratio per unit weight of cocoon, silk tenacity, and percent elongation. Thus, the present results show that polyamine treatment would influence silk quality at structural, mechanical, and molecular level in the Bombyx mori, which can be exploited in silk biomaterial production. © 2016 Wiley Periodicals, Inc.

  16. Water-insoluble Silk Films with Silk I Structure

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Q.; Hu, X; Wang, X; Kluge, J; Lu, S; Cebe, P; Kaplan, D

    2010-01-01

    Water-insoluble regenerated silk materials are normally produced by increasing the {beta}-sheet content (silk II). In the present study water-insoluble silk films were prepared by controlling the very slow drying of Bombyx mori silk solutions, resulting in the formation of stable films with a predominant silk I instead of silk II structure. Wide angle X-ray scattering indicated that the silk films stabilized by slow drying were mainly composed of silk I rather than silk II, while water- and methanol-annealed silk films had a higher silk II content. The silk films prepared by slow drying had a globule-like structure at the core surrounded by nano-filaments. The core region was composed of silk I and silk II, surrounded by hydrophilic nano-filaments containing random turns and {alpha}-helix secondary structures. The insoluble silk films prepared by slow drying had unique thermal, mechanical and degradative properties. Differential scanning calorimetry results revealed that silk I crystals had stable thermal properties up to 250 C, without crystallization above the T{sub g}, but degraded at lower temperatures than silk II structure. Compared with water- and methanol-annealed films the films prepared by slow drying had better mechanical ductility and were more rapidly enzymatically degraded, reflecting the differences in secondary structure achieved via differences in post processing of the cast silk films. Importantly, the silk I structure, a key intermediate secondary structure for the formation of mechanically robust natural silk fibers, was successfully generated by the present approach of very slow drying, mimicking the natural process. The results also point to a new mode of generating new types of silk biomaterials with enhanced mechanical properties and increased degradation rates, while maintaining water insolubility, along with a low {beta}-sheet content.

  17. DNA preservation in silk.

    Science.gov (United States)

    Liu, Yawen; Zheng, Zhaozhu; Gong, He; Liu, Meng; Guo, Shaozhe; Li, Gang; Wang, Xiaoqin; Kaplan, David L

    2017-06-27

    The structure of DNA is susceptible to alterations at high temperature and on changing pH, irradiation and exposure to DNase. Options to protect and preserve DNA during storage are important for applications in genetic diagnosis, identity authentication, drug development and bioresearch. In the present study, the stability of total DNA purified from human dermal fibroblast cells, as well as that of plasmid DNA, was studied in silk protein materials. The DNA/silk mixtures were stabilized on filter paper (silk/DNA + filter) or filter paper pre-coated with silk and treated with methanol (silk/DNA + PT-filter) as a route to practical utility. After air-drying and water extraction, 50-70% of the DNA and silk could be retrieved and showed a single band on electrophoretic gels. 6% silk/DNA + PT-filter samples provided improved stability in comparison with 3% silk/DNA + filter samples and DNA + filter samples for DNA preservation, with ∼40% of the band intensity remaining at 37 °C after 40 days and ∼10% after exposure to UV light for 10 hours. Quantitative analysis using the PicoGreen assay confirmed the results. The use of Tris/borate/EDTA (TBE) buffer enhanced the preservation and/or extraction of the DNA. The DNA extracted after storage maintained integrity and function based on serving as a functional template for PCR amplification of the gene for zinc finger protein 750 (ZNF750) and for transgene expression of red fluorescence protein (dsRed) in HEK293 cells. The high molecular weight and high content of a crystalline beta-sheet structure formed on the coated surfaces likely accounted for the preservation effects observed for the silk/DNA + PT-filter samples. Although similar preservation effects were also obtained for lyophilized silk/DNA samples, the rapid and simple processing available with the silk-DNA-filter membrane system makes it appealing for future applications.

  18. Silk-based biomaterials.

    Science.gov (United States)

    Altman, Gregory H; Diaz, Frank; Jakuba, Caroline; Calabro, Tara; Horan, Rebecca L; Chen, Jingsong; Lu, Helen; Richmond, John; Kaplan, David L

    2003-02-01

    Silk from the silkworm, Bombyx mori, has been used as biomedical suture material for centuries. The unique mechanical properties of these fibers provided important clinical repair options for many applications. During the past 20 years, some biocompatibility problems have been reported for silkworm silk; however, contamination from residual sericin (glue-like proteins) was the likely cause. More recent studies with well-defined silkworm silk fibers and films suggest that the core silk fibroin fibers exhibit comparable biocompatibility in vitro and in vivo with other commonly used biomaterials such as polylactic acid and collagen. Furthermore, the unique mechanical properties of the silk fibers, the diversity of side chain chemistries for 'decoration' with growth and adhesion factors, and the ability to genetically tailor the protein provide additional rationale for the exploration of this family of fibrous proteins for biomaterial applications. For example, in designing scaffolds for tissue engineering these properties are particularly relevant and recent results with bone and ligament formation in vitro support the potential role for this biomaterial in future applications. To date, studies with silks to address biomaterial and matrix scaffold needs have focused on silkworm silk. With the diversity of silk-like fibrous proteins from spiders and insects, a range of native or bioengineered variants can be expected for application to a diverse set of clinical needs.

  19. Characterization and assembly of a GFP-tagged cylindriform silk into hexameric complexes.

    Science.gov (United States)

    Öster, Carl; Svensson Bonde, Johan; Bülow, Leif; Dicko, Cedric

    2014-04-01

    Spider silk has been studied extensively for its attractive mechanical properties and potential applications in medicine and industry. The production of spider silk, however, has been lagging behind for lack of suitable systems. Our approach focuses on solving the production of spider silk by designing, expressing, purifying and characterizing the silk from cylindriform glands. We show that the cylindriform silk protein, in contrast to the commonly used dragline silk protein, is fully folded and stable in solution. With the help of GFP as a fusion tag we enhanced the expression of the silk protein in Escherichia coli and could optimize the downstream processing. Secondary structures analysis by circular dichroism and FTIR shows that the GFP-silk fusion protein is predominantly α-helical, and that pH can trigger a α- to β-transition resulting in aggregation. Structural analysis by small angle X-ray scattering suggests that the GFP-Silk exists in the form of a hexamer in solution. Copyright © 2013 Wiley Periodicals, Inc.

  20. Ultrastructure of the silk glands in three adult females of sphecid wasps of the genus Microstigmus (Hymenoptera: Pemphredoninae Ultraestructura de las glándulas de seda en hembras adultas de tres especies de avispas del género Microstigmus (Hymenoptera: Sphecidae: Pemphredoninae

    Directory of Open Access Journals (Sweden)

    JOSÉ EDUARDO SERRÃO

    2005-03-01

    Full Text Available The ultrastructure of silk glands in adult females of sphecid wasps is described. Individual glands are scattered in the more posterior portion of the metasoma being each gland formed by an enlarged secretory unity with one conducting canal. Each secretory unit is a gland cell containing a large lumen and numerous secretory granules, which are delimited by membrane and filled with middle electron dense content of homogeneous aspect, which are exocytosed into the extra cellular lumen. Cell cytoplasm is filled with rough endoplasmic reticulum, polyribosomes and Golgi apparatuses profiles. The basal plasma membrane has many short infoldings and is lined by a thin basement membrane. The apical membrane is invaginated to form the boundary of the lumen, containing scattered short microvilli. The cells are mononucleated and the nucleus is pleomorphic containing disperse chromatin. The extracellular lumen is separated of the receiving canal by a convoluted sponge-like wall forming many villi, which in their tip are lined by a thin single layered cuticle. In the basal region of the villi a cuticular covering is lacking. In the conducting canal secretion acquire two different electron densities. A thin cuticle lines the lumen of conducting canal and the cell cytoplasm is scarce and the organelles are represented for few rough endoplasmic reticulum and polyribosomes. These results are discussed in relation to function and origin of silk gland in adult SphecidaeSe describe la ultraestructura de las glándulas de la seda en tres hembras adultas de avispas Sphecidae del género Microstigmus. Las glándulas individualmente se dispersan en la porción más posterior del metasoma, y cada una de ellas está formada por una unidad secretora grande y un canal que conduce la secreción. Cada célula de la unidad secretora contiene un gran lumen y numerosos gránulos secretores, los que están delimitados por una membrana y repletos de un contenido denso a los

  1. Untangling spider silk evolution with spidroin terminal domains

    Directory of Open Access Journals (Sweden)

    Garb Jessica E

    2010-08-01

    Full Text Available Abstract Background Spidroins are a unique family of large, structural proteins that make up the bulk of spider silk fibers. Due to the highly variable nature of their repetitive sequences, spidroin evolutionary relationships have principally been determined from their non-repetitive carboxy (C-terminal domains, though they offer limited character data. The few known spidroin amino (N-terminal domains have been difficult to obtain, but potentially contain critical phylogenetic information for reconstructing the diversification of spider silks. Here we used silk gland expression data (ESTs from highly divergent species to evaluate the functional significance and phylogenetic utility of spidroin N-terminal domains. Results 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. Conclusions 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

  2. Silk I and Silk II studied by fast scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cebe, Peggy; Partlow, Benjamin P.; Kaplan, David L.; Wurm, Andreas; Zhuravlev, Evgeny; Schick, Christoph

    2017-06-01

    Using fast scanning calorimetry (FSC), we investigated the glass transition and crystal melting of samples of B. mori silk fibroin containing Silk I and/or Silk II crystals. Due to the very short residence times at high temperatures during such measurements, thermal decomposition of silk protein can be significantly suppressed. FSC was performed at 2000 K/s using the Mettler Flash DSC1 on fibroin films with masses around 130–270 ng. Films were prepared with different crystalline fractions (ranging from 0.26 to 0.50) and with different crystal structures (Silk I, Silk II, or mixed) by varying the processing conditions. These included water annealing at different temperatures, exposure to 50% MeOH in water, or autoclaving. The resulting crystal structure was examined using wide angle X-ray scattering. Degree of crystallinity was evaluated from Fourier transform infrared (FTIR) spectroscopy and from analysis of the heat capacity increment at the glass transition temperature. Silk fibroin films prepared by water annealing at 25 °C were the least crystalline and had Silk I structure. FTIR and FSC studies showed that films prepared by autoclaving or 50% MeOH exposure were the most crystalline and had Silk II structure. Intermediate crystalline fraction and mixed Silk I/Silk II structures were found in films prepared by water annealing at 37 °C. FSC results indicate that Silk II crystals exhibit endotherms of narrower width and have higher mean melting temperature Tm(II) = 351 ± 2.6 °C, compared to Silk I crystals which melt at Tm(I) = 292 ± 3.8 °C. Films containing mixed Silk I/Silk II structure showed two clearly separated endothermic peaks. Evidence suggests that the two types of crystals melt separately and do not thermally interconvert on the extremely short time scale (0.065 s between onset and end of melting) of the FSC experiment.

  3. Development and silk production by silkworm larvae after topical application of methoprene

    Directory of Open Access Journals (Sweden)

    Miranda José Ednilson

    2002-01-01

    Full Text Available Juvenile hormone analogues have been tested as insect growth regulators in silkworm (Bombyx mori, seeking an increment of silk production. These chemical products, when applied in small or moderate rates, promote the extension of the last larval instar. To understand the physiologic consequences on silk production by the silkworm strain C115 x N108, the application of methoprene, a juvenile hormone analogue, was performed to evaluate its effects on larval development and silk production. Methoprene was topically applied 48h after the fourth larval ecdysis, on the dorsal integument of the 2nd thoracic segment of the insects, at seven rates between 0 and 20 ng a.i. Methoprene influenced positively the duration of the fifth instar and the weight gain of the insects. The application of 1ng methoprene resulted in the heaviest silkglands, cocoons, shell cocoons and pupae weights. Comparatively to the control, the increment on silk production (approximately 24% by the use of 1ng methoprene was more accentuated than the corresponding negative effects on the cocooning rate (approximately 12%.

  4. A highly divergent gene cluster in honey bees encodes a novel silk family.

    Science.gov (United States)

    Sutherland, Tara D; Campbell, Peter M; Weisman, Sarah; Trueman, Holly E; Sriskantha, Alagacone; Wanjura, Wolfgang J; Haritos, Victoria S

    2006-11-01

    The pupal cocoon of the domesticated silk moth Bombyx mori is the best known and most extensively studied insect silk. It is not widely known that Apis mellifera larvae also produce silk. We have used a combination of genomic and proteomic techniques to identify four honey bee fiber genes (AmelFibroin1-4) and two silk-associated genes (AmelSA1 and 2). The four fiber genes are small, comprise a single exon each, and are clustered on a short genomic region where the open reading frames are GC-rich amid low GC intergenic regions. The genes encode similar proteins that are highly helical and predicted to form unusually tight coiled coils. Despite the similarity in size, structure, and composition of the encoded proteins, the genes have low primary sequence identity. We propose that the four fiber genes have arisen from gene duplication events but have subsequently diverged significantly. The silk-associated genes encode proteins likely to act as a glue (AmelSA1) and involved in silk processing (AmelSA2). Although the silks of honey bees and silkmoths both originate in larval labial glands, the silk proteins are completely different in their primary, secondary, and tertiary structures as well as the genomic arrangement of the genes encoding them. This implies independent evolutionary origins for these functionally related proteins.

  5. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits

    Directory of Open Access Journals (Sweden)

    Christine Radtke

    2016-10-01

    Full Text Available Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropods including spiders, caterpillars and mites. The silk fibers are secreted by the labial gland of the larvae of some orders of Holometabola (insects with pupa or the spinnerets of spiders. The majority of studies using silks for biomedical applications use materials from silkworms or spiders, mostly of the genus Nephila clavipes. Silk is one of the most promising biomaterials with effects not only in nerve regeneration, but in a number of regenerative applications. The development of silks for human biomedical applications is of high scientific and clinical interest. Biomaterials in use for biomedical applications have to meet a number of requirements such as biocompatibility and elicitation of no more than a minor inflammatory response, biodegradability in a reasonable time and specific structural properties. Here we present the current status in the field of silk-based conduit development for nerve repair and discuss current advances with regard to potential clinical transfer of an implantable nerve conduit for enhancement of nerve regeneration.

  6. A Hox Gene, Antennapedia, Regulates Expression of Multiple Major Silk Protein Genes in the Silkworm Bombyx mori.

    Science.gov (United States)

    Tsubota, Takuya; Tomita, Shuichiro; Uchino, Keiro; Kimoto, Mai; Takiya, Shigeharu; Kajiwara, Hideyuki; Yamazaki, Toshimasa; Sezutsu, Hideki

    2016-03-25

    Hoxgenes play a pivotal role in the determination of anteroposterior axis specificity during bilaterian animal development. They do so by acting as a master control and regulating the expression of genes important for development. Recently, however, we showed that Hoxgenes can also function in terminally differentiated tissue of the lepidopteranBombyx mori In this species,Antennapedia(Antp) regulates expression of sericin-1, a major silk protein gene, in the silk gland. Here, we investigated whether Antpcan regulate expression of multiple genes in this tissue. By means of proteomic, RT-PCR, and in situ hybridization analyses, we demonstrate that misexpression of Antpin the posterior silk gland induced ectopic expression of major silk protein genes such assericin-3,fhxh4, and fhxh5 These genes are normally expressed specifically in the middle silk gland as is Antp Therefore, the evidence strongly suggests that Antpactivates these silk protein genes in the middle silk gland. The putativesericin-1 activator complex (middle silk gland-intermolt-specific complex) can bind to the upstream regions of these genes, suggesting that Antpdirectly activates their expression. We also found that the pattern of gene expression was well conserved between B. moriand the wild species Bombyx mandarina, indicating that the gene regulation mechanism identified here is an evolutionarily conserved mechanism and not an artifact of the domestication of B. mori We suggest that Hoxgenes have a role as a master control in terminally differentiated tissues, possibly acting as a primary regulator for a range of physiological processes. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Silk Electrogel Rheology

    Science.gov (United States)

    Tabatabai, A. P.; Urbach, J. S.; Blair, D. L.; Kaplan, D. L.

    2014-03-01

    We present experimental results on the rheology on electrogels derived from aqueous solutions of reconstituted Bombyx Mori silk fibroin protein. Through electrochemistry, the silk protein solution develops local pH changes resulting in the assembly of protein into a weak gel. We determine the physical properties of the electrogels by performing rheology and observe that they exhibit the characteristics of a crosslinked biopolymer network. Interestingly, we find that these silk gels exhibit linear elasticity over a range of up to two orders of magnitude larger than most crosslinked biopolymer networks. Moreover, the nonlinear rheology exhibits a strain-stiffening behavior that is fundamentally different than the strain-stiffening observed in crosslinked biopolymers. Through rheological techniques we aim to understand this distinctive material that cannot be explained by current polymeric models. This work is supported by a grant from the AFOSR FA9550-07-1-0130.

  8. Comparative Transcriptome Analysis Reveals Different Silk Yields of Two Silkworm Strains.

    Directory of Open Access Journals (Sweden)

    Juan Li

    Full Text Available Cocoon and silk yields are the most important characteristics of sericulture. However, few studies have examined the genes that modulate these features. Further studies of these genes will be useful for improving the products of sericulture. JingSong (JS and Lan10 (L10 are two strains having significantly different cocoon and silk yields. In the current study, RNA-Seq and quantitative polymerase chain reaction (qPCR were performed on both strains in order to determine divergence of the silk gland, which controls silk biosynthesis in silkworms. Compared with L10, JS had 1375 differentially expressed genes (DEGs; 738 up-regulated genes and 673 down-regulated genes. Nine enriched gene ontology (GO terms were identified by GO enrichment analysis based on these DEGs. KEGG enrichment analysis results showed that the DEGs were enriched in three pathways, which were mainly associated with the processing and biosynthesis of proteins. The representative genes in the enrichment pathways and ten significant DEGs were further verified by qPCR, the results of which were consistent with the RNA-Seq data. Our study has revealed differences in silk glands between the two silkworm strains and provides a perspective for understanding the molecular mechanisms determining silk yield.

  9. Structural Origins of Silk Piezoelectricity.

    Science.gov (United States)

    Yucel, Tuna; Cebe, Peggy; Kaplan, David L

    2011-02-22

    Uniaxially oriented, piezoelectric silk films were prepared by a two-step method that involved: (1) air drying aqueous, regenerated silk fibroin solutions into films, and (2) drawing the silk films to a desired draw ratio. The utility of two different drawing techniques, zone drawing and water immersion drawing were investigated for processing the silk for piezoelectric studies. Silk films zone drawn to a ratio of λ= 2.7 displayed relatively high dynamic shear piezoelectric coefficients of d(14) = -1.5 pC/N, corresponding to over two orders of magnitude increase in d(14) due to film drawing. A strong correlation was observed between the increase in the silk II, β-sheet content with increasing draw ratio measured by FTIR spectroscopy (C(β)∝ e(2.5) (λ)), the concomitant increasing degree of orientation of β-sheet crystals detected via WAXD (FWHM = 0.22° for λ= 2.7), and the improvement in silk piezoelectricity (d(14)∝ e(2.4) (λ)). Water immersion drawing led to a predominantly silk I structure with a low degree of orientation (FWHM = 75°) and a much weaker piezoelectric response compared to zone drawing. Similarly, increasing the β-sheet crystallinity without inducing crystal alignment, e.g. by methanol treatment, did not result in a significant enhancement of silk piezoelectricity. Overall, a combination of a high degree of silk II, β-sheet crystallinity and crystalline orientation are prerequisites for a strong piezoelectric effect in silk. Further understanding of the structural origins of silk piezoelectricity will provide important options for future biotechnological and biomedical applications of this protein.

  10. In Vitro Evaluation of Spider Silk Meshes as a Potential Biomaterial for Bladder Reconstruction

    NARCIS (Netherlands)

    Steins, A.; Dik, P.; Müller, W.H.; Vervoort, S.J.; Reimers, K.; Kubhier, J.W.; Vogt, P.M.; van Apeldoorn, Aart A.; Coffer, P.J.; Schepers, K.

    2015-01-01

    Reconstruction of the bladder by means of both natural and synthetic materials remains a challenge due to severe adverse effects such as mechanical failure. Here we investigate the application of spider major ampullate gland-derived dragline silk from the Nephila edulis spider, a natural biomaterial

  11. Endocrine glands

    Science.gov (United States)

    ... Diabetes Gigantism Diabetes insipidus Cushing Disease Watch this video about: Pituitary gland Testes and ovaries: Lack of sex development (unclear genitalia) Thyroid: Congenital hypothyroidism Myxedema Goiter ...

  12. Journal of Biosciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Keywords. Bee; electron microscopy; larval salivary gland; light microscopy; polarized light microscopy; silk gland. Abstract. The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands were dissected and prepared for light and polarized light microscopy, as well ...

  13. Silk I and Silk II studied by fast scanning calorimetry.

    Science.gov (United States)

    Cebe, Peggy; Partlow, Benjamin P; Kaplan, David L; Wurm, Andreas; Zhuravlev, Evgeny; Schick, Christoph

    2017-06-01

    Using fast scanning calorimetry (FSC), we investigated the glass transition and crystal melting of samples of B. mori silk fibroin containing Silk I and/or Silk II crystals. Due to the very short residence times at high temperatures during such measurements, thermal decomposition of silk protein can be significantly suppressed. FSC was performed at 2000K/s using the Mettler Flash DSC1 on fibroin films with masses around 130-270ng. Films were prepared with different crystalline fractions (ranging from 0.26 to 0.50) and with different crystal structures (Silk I, Silk II, or mixed) by varying the processing conditions. These included water annealing at different temperatures, exposure to 50%MeOH in water, or autoclaving. The resulting crystal structure was examined using wide angle X-ray scattering. Degree of crystallinity was evaluated from Fourier transform infrared (FTIR) spectroscopy and from analysis of the heat capacity increment at the glass transition temperature. Silk fibroin films prepared by water annealing at 25°C were the least crystalline and had Silk I structure. FTIR and FSC studies showed that films prepared by autoclaving or 50%MeOH exposure were the most crystalline and had Silk II structure. Intermediate crystalline fraction and mixed Silk I/Silk II structures were found in films prepared by water annealing at 37°C. FSC results indicate that Silk II crystals exhibit endotherms of narrower width and have higher mean melting temperature T m (II)=351±2.6°C, compared to Silk I crystals which melt at T m (I)=292±3.8°C. Films containing mixed Silk I/Silk II structure showed two clearly separated endothermic peaks. Evidence suggests that the two types of crystals melt separately and do not thermally interconvert on the extremely short time scale (0.065s between onset and end of melting) of the FSC experiment. Silkworm silk is a naturally occurring biomaterial. The fibroin component of silk forms two types of crystals. Silk properties depend upon the

  14. Silk Film Embossing System

    Science.gov (United States)

    Paquette, Mark S.

    New tools are often required to facilitate new discoveries and test new methods. Commercial offerings can be prohibitively expensive and difficult to customize. The development of ad-hoc tools provides the most flexibility and provides an opportunity to modify and refine a technology. An embossing system was developed for silk film imprinting and stamping in order to facilitate and add versatility to the efforts involving micro- and nanoscale device manufacturing in biopolymers. This system features temperature controlled embossing surfaces, adjustable embossing pressures, and variable embossing times. The device can also be fitted with interchangeable temperature controlled embossing and stamping tools. The design, development, fabrication, applications, and future improvements are explored for the system. This device may facilitate new discoveries in the realm of biopolymer micro- and nanomanufacturing and may provide a path towards high volume production of silk film based technologies.

  15. Gamma radiation effects of 60 Co on Bombyx mori (Lep., Bombycidae) modifying the silk fiber production

    International Nuclear Information System (INIS)

    Carneiro Junior, Francisco; Bendassolli, Jose A.

    1997-01-01

    The present work aimed to verify the biological effects of the application of different doses of gamma radiation during the fifth instar of the silkworm catepillar. Sevently eight silkworm caterpillars (Bombyx mori) were irradiated with γ 60 Co radiation at the initial period of the fifth instar. The caterpillars were divided and classified in six batches of thirteen individuals each. Treatments 1 through 5 received 20, 40, 60, 80 and 100 Gy, respectively, and the control, also consisted of thirteen caterpillars, was not irradiated. The results showed a general increase in the silk fiber content in the irradiated batches compared to the control. The weight of the silk cocoons was higher with increasing doses of irradiation, from 20 to 80 Gy, respectively, followed by a decrease in weight in the treatment irradiated with 100 Gy. the results obtained in this experiment enable the conclusion that the radiation applied to the caterpillars significantly influenced the production of silk fiber in this species. (author). 4 refs., 2 figs., 3 tabs

  16. Structural Analysis of Hand Drawn Bumblebee Bombus terrestris Silk

    Directory of Open Access Journals (Sweden)

    Andrea L. Woodhead

    2016-07-01

    Full Text Available Bombus terrestris, commonly known as the buff-tailed bumblebee, is native to Europe, parts of Africa and Asia. It is commercially bred for use as a pollinator of greenhouse crops. Larvae pupate within a silken cocoon that they construct from proteins produced in modified salivary glands. The amino acid composition and protein structure of hand drawn B. terrestris, silk fibres was investigated through the use of micro-Raman spectroscopy. Spectra were obtained from single fibres drawn from the larvae salivary gland at a rate of 0.14 cm/s. Raman spectroscopy enabled the identification of poly(alanine, poly(alanine-glycine, phenylalanine, tryptophan, and methionine, which is consistent with the results of amino acid analysis. The dominant protein conformation was found to be coiled coil (73% while the β-sheet content of 10% is, as expected, lower than those reported for hornets and ants. Polarized Raman spectra revealed that the coiled coils were highly aligned along the fibre axis while the β-sheet and random coil components had their peptide carbonyl groups roughly perpendicular to the fibre axis. The protein orientation distribution is compared to those of other natural and recombinant silks. A structural model for the B. terrestris silk fibre is proposed based on these results.

  17. Applicability of biotechnologically produced insect silks.

    Science.gov (United States)

    Herold, Heike M; Scheibel, Thomas

    2017-09-26

    Silks are structural proteins produced by arthropods. Besides the well-known cocoon silk, which is produced by larvae of the silk moth Bombyx mori to undergo metamorphosis inside their silken shelter (and which is also used for textile production by men since millennia), numerous further less known silk-producing animals exist. The ability to produce silk evolved multiple independent times during evolution, and the fact that silk was subject to convergent evolution gave rise to an abundant natural diversity of silk proteins. Silks are used in air, under water, or like honey bee silk in the hydrophobic, waxen environment of the bee hive. The good mechanical properties of insect silk fibres together with their non-toxic, biocompatible, and biodegradable nature renders these materials appealing for both technical and biomedical applications. Although nature provides a great diversity of material properties, the variation in quality inherent in materials from natural sources together with low availability (except from silkworm silk) impeded the development of applications of silks. To overcome these two drawbacks, in recent years, recombinant silks gained more and more interest, as the biotechnological production of silk proteins allows for a scalable production at constant quality. This review summarises recent developments in recombinant silk production as well as technical procedures to process recombinant silk proteins into fibres, films, and hydrogels.

  18. Duplication and concerted evolution of MiSp-encoding genes underlie the material properties of minor ampullate silks of cobweb weaving spiders.

    Science.gov (United States)

    Vienneau-Hathaway, Jannelle M; Brassfield, Elizabeth R; Lane, Amanda Kelly; Collin, Matthew A; Correa-Garhwal, Sandra M; Clarke, Thomas H; Schwager, Evelyn E; Garb, Jessica E; Hayashi, Cheryl Y; Ayoub, Nadia A

    2017-03-14

    Orb-web weaving spiders and their relatives use multiple types of task-specific silks. The majority of spider silk studies have focused on the ultra-tough dragline silk synthesized in major ampullate glands, but other silk types have impressive material properties. For instance, minor ampullate silks of orb-web weaving spiders are as tough as draglines, due to their higher extensibility despite lower strength. Differences in material properties between silk types result from differences in their component proteins, particularly members of the spidroin (spider fibroin) gene family. However, the extent to which variation in material properties within a single silk type can be explained by variation in spidroin sequences is unknown. Here, we compare the minor ampullate spidroins (MiSp) of orb-weavers and cobweb weavers. Orb-web weavers use minor ampullate silk to form the auxiliary spiral of the orb-web while cobweb weavers use it to wrap prey, suggesting that selection pressures on minor ampullate spidroins (MiSp) may differ between the two groups. We report complete or nearly complete MiSp sequences from five cobweb weaving spider species and measure material properties of minor ampullate silks in a subset of these species. We also compare MiSp sequences and silk properties of our cobweb weavers to published data for orb-web weavers. We demonstrate that all our cobweb weavers possess multiple MiSp loci and that one locus is more highly expressed in at least two species. We also find that the proportion of β-spiral-forming amino acid motifs in MiSp positively correlates with minor ampullate silk extensibility across orb-web and cobweb weavers. MiSp sequences vary dramatically within and among spider species, and have likely been subject to multiple rounds of gene duplication and concerted evolution, which have contributed to the diverse material properties of minor ampullate silks. Our sequences also provide templates for recombinant silk proteins with tailored

  19. Surface ultrastructure of third-instar Megaselia scalaris (Diptera: Phoridae

    Directory of Open Access Journals (Sweden)

    Sukontason Kabkaew L

    2002-01-01

    Full Text Available We describe some ultrastructure of the third-instar Megaselia scalaris (Diptera: Phoridae using scanning electron microscopy, with the cephalic segment, anterior spiracle and posterior spiracle being emphasized. This study provides the taxonomic information of this larval species, which may be useful to differentiate from other closely-related species.

  20. Invited review nonmulberry silk biopolymers.

    Science.gov (United States)

    Kundu, S C; Kundu, Banani; Talukdar, Sarmistha; Bano, Subia; Nayak, Sunita; Kundu, Joydip; Mandal, Biman B; Bhardwaj, Nandana; Botlagunta, Mahendran; Dash, Biraja C; Acharya, Chitrangada; Ghosh, Ananta K

    2012-06-01

    The silk produced by silkworms are biopolymers and can be classified into two types--mulberry and nonmulberry. Mulberry silk of silkworm Bombyx mori has been extensively explored and used for century old textiles and sutures. But for the last few decades it is being extensively exploited for biomedical applications. However, the transformation of nonmulberry silk from being a textile commodity to biomaterials is relatively new. Within a very short period of time, the combination of load bearing capability and tensile strength of nonmulberry silk has been equally envisioned for bone, cartilage, adipose, and other tissue regeneration. Adding to its advantage is its diverse morphology, including macro to nano architectures with controllable degradation and biocompatibility yields novel natural material systems in vitro. Its follow on applications involve sustained release of model compounds and anticancer drugs. Its 3D cancer models provide compatible microenvironment systems for better understanding of the cancer progression mechanism and screening of anticancer compounds. Diversely designed nonmulberry matrices thus provide an array of new cutting age technologies, which is unattainable with the current synthetic materials that lack biodegradability and biocompatibility. Scientific exploration of nonmulberry silk in tissue engineering, regenerative medicine, and biotechnological applications promises advancement of sericulture industries in India and China, largest nonmulberry silk producers of the world. This review discusses the prospective biomedical applications of nonmulberry silk proteins as natural biomaterials. Copyright © 2012 Wiley Periodicals, Inc.

  1. Synthetic spider silk fibers spun from Pyriform Spidroin 2, a glue silk protein discovered in orb-weaving spider attachment discs.

    Science.gov (United States)

    Geurts, Paul; Zhao, Liang; Hsia, Yang; Gnesa, Eric; Tang, Simon; Jeffery, Felicia; La Mattina, Coby; Franz, Andreas; Larkin, Leah; Vierra, Craig

    2010-12-13

    Spider attachment disc silk fibers are spun into a viscous liquid that rapidly solidifies, gluing dragline silk fibers to substrates for locomotion or web construction. Here we report the identification and artificial spinning of a novel attachment disc glue silk fibroin, Pyriform Spidroin 2 (PySp2), from the golden orb weaver Nephila clavipes . MS studies support PySp2 is a constituent of the pyriform gland that is spun into attachment discs. Analysis of the PySp2 protein architecture reveals sequence divergence relative to the other silk family members, including the cob weaver glue silk fibroin PySp1. PySp2 contains internal block repeats that consist of two subrepeat units: one dominated by Ser, Gln, and Ala and the other Pro-rich. Artificial spinning of recombinant PySp2 truncations shows that the Ser-Gln-Ala-rich subrepeat is sufficient for the assembly of polymeric subunits and subsequent fiber formation. These studies support that both orb- and cob-weaving spiders have evolved highly polar block-repeat sequences with the ability to self-assemble into fibers, suggesting a strategy to allow fiber fabrication in the liquid environment of the attachment discs.

  2. Optically probing torsional superelasticity in spider silks

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Bhupesh; Thakur, Ashish; Panda, Biswajit; Singh, Kamal P. [Department of Physical Sciences, IISER Mohali, Sector 81, Manauli, Mohali 140306 (India)

    2013-11-11

    We investigate torsion mechanics of various spider silks using a sensitive optical technique. We find that spider silks are torsionally superelastic in that they can reversibly withstand great torsion strains of over 10{sup 2−3} rotations per cm before failure. Among various silks from a spider, we find the failure twist-strain is greatest in the sticky capture silk followed by dragline and egg-case silk. Our in situ laser-diffraction measurements reveal that torsional strains on the silks induce a nano-scale transverse compression in its diameter that is linear and reversible. These unique torsional properties of the silks could find applications in silk-based materials and devices.

  3. Optically probing torsional superelasticity in spider silks

    International Nuclear Information System (INIS)

    Kumar, Bhupesh; Thakur, Ashish; Panda, Biswajit; Singh, Kamal P.

    2013-01-01

    We investigate torsion mechanics of various spider silks using a sensitive optical technique. We find that spider silks are torsionally superelastic in that they can reversibly withstand great torsion strains of over 10 2−3 rotations per cm before failure. Among various silks from a spider, we find the failure twist-strain is greatest in the sticky capture silk followed by dragline and egg-case silk. Our in situ laser-diffraction measurements reveal that torsional strains on the silks induce a nano-scale transverse compression in its diameter that is linear and reversible. These unique torsional properties of the silks could find applications in silk-based materials and devices

  4. A novel ecdysone receptor mediates steroid-regulated developmental events during the mid-third instar of Drosophila.

    Directory of Open Access Journals (Sweden)

    Benjamin F B Costantino

    2008-06-01

    Full Text Available The larval salivary gland of Drosophila melanogaster synthesizes and secretes glue glycoproteins that cement developing animals to a solid surface during metamorphosis. The steroid hormone 20-hydroxyecdysone (20E is an essential signaling molecule that modulates most of the physiological functions of the larval gland. At the end of larval development, it is known that 20E--signaling through a nuclear receptor heterodimer consisting of EcR and USP--induces the early and late puffing cascade of the polytene chromosomes and causes the exocytosis of stored glue granules into the lumen of the gland. It has also been reported that an earlier pulse of hormone induces the temporally and spatially specific transcriptional activation of the glue genes; however, the receptor responsible for triggering this response has not been characterized. Here we show that the coordinated expression of the glue genes midway through the third instar is mediated by 20E acting to induce genes of the Broad Complex (BRC through a receptor that is not an EcR/USP heterodimer. This result is novel because it demonstrates for the first time that at least some 20E-mediated, mid-larval, developmental responses are controlled by an uncharacterized receptor that does not contain an RXR-like component.

  5. Structural study of Bombyx mori silk fibroin during processing for regeneration

    Science.gov (United States)

    Ha, Sung-Won

    means the proceeding backbone direction is changed 180° by this sequence. This may facilitate the beta-sheet formation of the crystal forming building blocks, GAGAGS/GY˜GY sequences, in fibroin heavy chain. It may also facilitate the solubilization of the fibroin heavy chain within the silk gland.

  6. Recombinant DNA production of spider silk proteins.

    Science.gov (United States)

    Tokareva, Olena; Michalczechen-Lacerda, Valquíria A; Rech, Elíbio L; Kaplan, David L

    2013-11-01

    Spider dragline silk is considered to be the toughest biopolymer on Earth due to an extraordinary combination of strength and elasticity. Moreover, silks are biocompatible and biodegradable protein-based materials. Recent advances in genetic engineering make it possible to produce recombinant silks in heterologous hosts, opening up opportunities for large-scale production of recombinant silks for various biomedical and material science applications. We review the current strategies to produce recombinant spider silks. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  7. PEGylated Silk Nanoparticles for Anticancer Drug Delivery.

    Science.gov (United States)

    Wongpinyochit, Thidarat; Uhlmann, Petra; Urquhart, Andrew J; Seib, F Philipp

    2015-11-09

    Silk has a robust clinical track record and is emerging as a promising biopolymer for drug delivery, including its use as nanomedicine. However, silk-based nanomedicines still require further refinements for full exploitation of their potential; the application of "stealth" design principals is especially necessary to support their evolution. The aim of this study was to develop and examine the potential of PEGylated silk nanoparticles as an anticancer drug delivery system. We first generated B. mori derived silk nanoparticles by driving β-sheet assembly (size 104 ± 1.7 nm, zeta potential -56 ± 5.6 mV) using nanoprecipitation. We then surface grafted polyethylene glycol (PEG) to the fabricated silk nanoparticles and verified the aqueous stability and morphology of the resulting PEGylated silk nanoparticles. We assessed the drug loading and release behavior of these nanoparticles using clinically established and emerging anticancer drugs. Overall, PEGylated silk nanoparticles showed high encapsulation efficiency (>93%) and a pH-dependent release over 14 days. Finally, we demonstrated significant cytotoxicity of drug loaded silk nanoparticles applied as single and combination nanomedicines to human breast cancer cells. In conclusion, these results, taken together with prior silk nanoparticle data, support a viable future for silk-based nanomedicines.

  8. Thymus Gland Anatomy

    Science.gov (United States)

    ... historical Searches are case-insensitive Thymus Gland, Adult, Anatomy Add to My Pictures View /Download : Small: 720x576 ... Large: 3000x2400 View Download Title: Thymus Gland, Adult, Anatomy Description: Anatomy of the thymus gland; drawing shows ...

  9. Adrenal Gland Tumors: Statistics

    Science.gov (United States)

    ... Gland Tumor: Statistics Request Permissions Adrenal Gland Tumor: Statistics Approved by the Cancer.Net Editorial Board , 03/ ... primary adrenal gland tumor is very uncommon. Exact statistics are not available for this type of tumor ...

  10. Aquaporins and Gland Secretion.

    Science.gov (United States)

    Delporte, Christine

    2017-01-01

    Aquaporins (AQPs ) are expressed in most exocrine and endocrine secretory glands. Consequently, summarizing the expression and functions of AQPs in secretory glands represents a daunting task considering the important number of glands present in the body, as well as the number of mammalian AQPs - thirteen. The roles played by AQPs in secretory processes have been investigated in many secretory glands. However, despite considerable research, additional studies are clearly needed to pursue our understanding of the role played by AQPs in secretory processes. This book chapter will focus on summarizing the current knowledge on AQPs expression and function in the gastrointestinal tract , including salivary glands, gastric glands, Duodenal Brunner's gland, liver and gallbladder, intestinal goblets cells, exocrine and endocrine pancreas, as well as few other secretory glands including airway submucosal glands, lacrimal glands, mammary glands and eccrine sweat glands.

  11. Effect of. gamma. -irradiation on the crystalline structure of silk fibroin and silk sericin

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, Masuhiro; Aoki, Akira

    1985-02-01

    Changes in the crystalline structure of silk sericin and silk fibroin induced by gamma-irradiation in the atmosphere described. The crystalline structure of silk sericin which had been subjected to gamma-irradiation remained unchanged. However the decomposition temperature of the specimen decreased to about 230 deg C, when the total dose of ..gamma.. rays exceeded 4.6 Mrad. The structure of the silk 1 type crystal of silk fibroin in the solid state, with a low degree of molecular orientation, changed into the silk 2 type crystal, when the total dose of ..gamma.. rays exceeded 4.6 Mrad. No changes in the crystalline structure were observed in the solid state of the silk 2 type crystal regardless of gamma-irradiation. The decrease in the decomposition temperature of the specimen was attributed to the decrease in the molecular orientation. However, the molecular conformation of silk fibroin with a randomly coiled structure remained unchanged even after gamma-irradiation.

  12. Politics of contemporary "Silk Roads"

    Directory of Open Access Journals (Sweden)

    Andrey I. Litvinov

    2016-01-01

    Full Text Available Recently in mass media we can find the idea about a new Silk Road or the concept of "Silk Road Economic Belt" which has been formulated by the Chinese PresidentXi Jinping on September 7,2013, during his official visit to Kazakhstan. This project is not only the creation of a transport, power and trade corridor, and also the project which will promote development of tourism in the region and to strengthening of cultural exchanges of China with the countries of Central Asia, it also includes construction of a network of high-speed fiber-optical networks. The economic strip of the Silk Road will begin in China and pass across the Central and the Southern Asia, part of branches across the territory of the Russian Federation and to leave to Europe. This international investment project assumes creation of a continental transport way. For implementation of overland part of "A great Silk Road is a three railway corridors (northern, central have to be constructed and southern They have form a basis for development of other means of transport, including automobile subsequently. Construction of these three railway corridors acts as the most important and necessary stage of implementation of the project. The government of China declares that creation of an economic belt of the Silk way is a revival of once prospering trade-transport and cultural corridor from Asia to Europe which will promote activization of a friendly exchange between the people of the different countries. Further all this has to connect trade and economic space of Europe and Asia in a whole that has to serve implementation of deeper economic cooperation, between the countries participating in him, to increase in a trade turnover and expansion of scientific and technical exchanges between them.

  13. PEGylated Silk Nanoparticles for Anticancer Drug Delivery

    DEFF Research Database (Denmark)

    Wongpinyochit, Thidarat; Uhlmann, Petra; Urquhart, Andrew

    2015-01-01

    Silk has a robust clinical track record and is emerging as a promising biopolymer for drug delivery, including its use as nanomedicine. However, silk-based nanomedicines still require further refinements for full exploitation of their potential; the application of “stealth” design principals...... is especially necessary to support their evolution. The aim of this study was to develop and examine the potential of PEGylated silk nanoparticles as an anticancer drug delivery system. We first generated B. mori derived silk nanoparticles by driving β-sheet assembly (size 104 ± 1.7 nm, zeta potential −56 ± 5.......6 mV) using nanoprecipitation. We then surface grafted polyethylene glycol (PEG) to the fabricated silk nanoparticles and verified the aqueous stability and morphology of the resulting PEGylated silk nanoparticles. We assessed the drug loading and release behavior of these nanoparticles using...

  14. Silk nanoparticles—an emerging anticancer nanomedicine

    Directory of Open Access Journals (Sweden)

    F. Philipp Seib

    2017-03-01

    Full Text Available Silk is a sustainable and ecologically friendly biopolymer with a robust clinical track record in humans for load bearing applications, in part due to its excellent mechanical properties and biocompatibility. Our ability to take bottom-up and top-down approaches for the generation of silk (inspired biopolymers has been critical in supporting the evolution of silk materials and formats, including silk nanoparticles for drug delivery. Silk nanoparticles are emerging as interesting contenders for drug delivery and are well placed to advance the nanomedicine field. This review covers the use of Bombyx mori and recombinant silks as an anticancer nanomedicine, highlighting the emerging trends and developments as well as critically assessing the current opportunities and challenges by providing a context specific assessment of this multidisciplinary field.

  15. Thromboelastometric and platelet responses to silk biomaterials.

    Science.gov (United States)

    Kundu, Banani; Schlimp, Christoph J; Nürnberger, Sylvia; Redl, Heinz; Kundu, S C

    2014-05-13

    Silkworm's silk is natural biopolymer with unique properties including mechanical robustness, all aqueous base processing and ease in fabrication into different multifunctional templates. Additionally, the nonmulberry silks have cell adhesion promoting tri-peptide (RGD) sequences, which make it an immensely potential platform for regenerative medicine. The compatibility of nonmulberry silk with human blood is still elusive; thereby, restricts its further application as implants. The present study, therefore, evaluate the haematocompatibility of silk biomaterials in terms of platelet interaction after exposure to nonmulberry silk of Antheraea mylitta using thromboelastometry (ROTEM). The mulberry silk of Bombyx mori and clinically used Uni-Graft W biomaterial serve as references. Shortened clotting time, clot formation times as well as enhanced clot strength indicate the platelet mediated activation of blood coagulation cascade by tested biomaterials; which is comparable to controls.

  16. Adrenal Gland Disorders: Condition Information

    Science.gov (United States)

    ... About Share Facebook Twitter Pinterest Email Print About Adrenal Gland Disorders The adrenal glands, located on the top of ... as estrogen and testosterone. What are adrenal gland disorders? Adrenal gland disorders occur when the adrenal glands do not ...

  17. The Use of Silk in Nanomedicine Applications

    DEFF Research Database (Denmark)

    Chiasson, Raymond; Hasan, Moaraj; Al Nazer, Q.

    2016-01-01

    Biopolymers made up of silk proteins have been used in numerous drug delivery applications and represent an excellent source of natural biomaterials. In particular silk fibroin has proved valuable as a building block for nanomedicines and drug delivery implants, owing to its favorable...... biocompatibility, degradation, stabilization and controllability. In this chapter we will discuss the various sources of silk biomaterial and how this naturally occurring biopolymer has been utilized in the development of nanomedicines and implantable drug delivery systems, demonstrating how silk is a unique...

  18. The Silk Route from Land to Sea

    Directory of Open Access Journals (Sweden)

    Jack Weatherford

    2018-04-01

    Full Text Available The Silk Route reached its historic and economic apogee under the Mongol Empire (1207–1368, as a direct result of the policies of Chinggis Khan (Genghis Khan and his successors. Because the land network proved inefficient for the amount of goods needing transport from one part of the empire to another, the Mongols expanded the Silk Route to ocean shipping and thus created the first Maritime Silk Route. The sea traffic initially expanded the land routes but soon strangled them. With the expansion of the Maritime Silk Route through the fourteenth century, the land connections reverted to local networks and lost their global importance.

  19. Molecular architecture of silk fibroin of Indian golden silkmoth, Antheraea assama.

    Science.gov (United States)

    Gupta, Adarsh K; Mita, Kazuei; Arunkumar, Kallare P; Nagaraju, Javaregowda

    2015-08-03

    The golden silk spun by Indian golden silkmoth Antheraea assama, is regarded for its shimmering golden luster, tenacity and value as biomaterial. This report describes the gene coding for golden silk H-fibroin (AaFhc), its expression, full-length sequence and structurally important motifs discerning the underlying genetic and biochemical factors responsible for its much sought-after properties. The coding region, with biased isocodons, encodes highly repetitious crystalline core, flanked by a pair of 5' and 3' non-repetitious ends. AaFhc mRNA expression is strictly territorial, confined to the posterior silk gland, encoding a protein of size 230 kDa, which makes homodimers making the elementary structural units of the fibrous core of the golden silk. Characteristic polyalanine repeats that make tight β-sheet crystals alternate with non-polyalanine repeats that make less orderly antiparallel β-sheets, β-turns and partial α-helices. Phylogenetic analysis of the conserved N-terminal amorphous motif and the comparative analysis of the crystalline region with other saturniid H-fibroins reveal that AaFhc has longer, numerous and relatively uniform repeat motifs with lower serine content that assume tighter β-crystals and denser packing, which are speculated to be responsible for its acclaimed properties of higher tensile strength and higher refractive index responsible for golden luster.

  20. Trends in World Silk Cocoons and Silk Production and Trade, 2007-2010

    Directory of Open Access Journals (Sweden)

    AGATHA AGATHA POPESCU

    2013-10-01

    Full Text Available The paper aimed to analyze world production and trade for fresh silk cocoons and raw silk using FAO Stat data for  the  period 2007-2010. The use of index, share and comparison methods allowed to identify the major trends in the analyzed period. Silk decline was determined by the increased importance of cotton and artificial fibres in textile and clothing industry. Important changes are taking place on silk cocoons and silk market. While, the European market decreased, the Asian market has mainly developed fresh cocoons and raw silk, while the European market became more interested of clothes. Silk consumption declined because of consumer’s preference for synthetic fibres, except traditional consumers from Asia.  China is the main producer and exporter of fresh and dry cocoons, while raw silk is produced and exported by China, Brazil and Italy and imported by India, Japan and Italy. In Europe, Bulgaria is the top producer of fresh cocoons and raw silk and Italy is the main raw silk importer and the top producer and exporter of textile and fashion clothes. Silk will remain an important raw material for producing high quality and luxury clothes.

  1. Silk film biomaterials for ocular surface repair

    Science.gov (United States)

    Lawrence, Brian David

    Current biomaterial approaches for repairing the cornea's ocular surface upon injury are partially effective due to inherent material limitations. As a result there is a need to expand the biomaterial options available for use in the eye, which in turn will help to expand new clinical innovations and technology development. The studies illustrated here are a collection of work to further characterize silk film biomaterials for use on the ocular surface. Silk films were produced from regenerated fibroin protein solution derived from the Bombyx mori silkworm cocoon. Methods of silk film processing and production were developed to produce consistent biomaterials for in vitro and in vivo evaluation. A wide range of experiments was undertaken that spanned from in vitro silk film material characterization to in vivo evaluation. It was found that a variety of silk film properties could be controlled through a water-annealing process. Silk films were then generated that could be use in vitro to produce stratified corneal epithelial cell sheets comparable to tissue grown on the clinical standard substrate of amniotic membrane. This understanding was translated to produce a silk film design that enhanced corneal healing in vivo on a rabbit injury model. Further work produced silk films with varying surface topographies that were used as a simplified analog to the corneal basement membrane surface in vitro. These studies demonstrated that silk film surface topography is capable of directing corneal epithelial cell attachment, growth, and migration response. Most notably epithelial tissue development was controllably directed by the presence of the silk surface topography through increasing cell sheet migration efficiency at the individual cellular level. Taken together, the presented findings represent a comprehensive characterization of silk film biomaterials for use in ocular surface reconstruction, and indicate their utility as a potential material choice in the

  2. Punctuated evolution of viscid silk in spider orb webs supported by mechanical behavior of wet cribellate silk

    Science.gov (United States)

    Piorkowski, Dakota; Blackledge, Todd A.

    2017-08-01

    The origin of viscid capture silk in orb webs, from cribellate silk-spinning ancestors, is a key innovation correlated with significant diversification of web-building spiders. Ancestral cribellate silk consists of dry nanofibrils surrounding a stiff, axial fiber that adheres to prey through van der Waals interactions, capillary forces, and physical entanglement. In contrast, viscid silk uses chemically adhesive aqueous glue coated onto a highly compliant and extensible flagelliform core silk. The extensibility of the flagelliform fiber accounts for half of the total work of adhesion for viscid silk and is enabled by water in the aqueous coating. Recent cDNA libraries revealed the expression of flagelliform silk proteins in cribellate orb-weaving spiders. We hypothesized that the presence of flagelliform proteins in cribellate silk could have allowed for a gradual shift in mechanical performance of cribellate axial silk, whose effect was masked by the dry nature of its adhesive. We measured supercontraction and mechanical performance of cribellate axial silk, in wet and dry states, for two species of cribellate orb web-weaving spiders to see if water enabled flagelliform silk-like performance. We found that compliance and extensibility of wet cribellate silk increased compared to dry state as expected. However, when compared to other silk types, the response to water was more similar to other web silks, like major and minor ampullate silk, than to viscid silk. These findings support the punctuated evolution of viscid silk mechanical performance.

  3. Fabrication of elastomeric silk fibers.

    Science.gov (United States)

    Bradner, Sarah A; Partlow, Benjamin P; Cebe, Peggy; Omenetto, Fiorenzo G; Kaplan, David L

    2017-09-01

    Methods to generate fibers from hydrogels, with control over mechanical properties, fiber diameter, and crystallinity, while retaining cytocompatibility and degradability, would expand options for biomaterials. Here, we exploited features of silk fibroin protein for the formation of tunable silk hydrogel fibers. The biological, chemical, and morphological features inherent to silk were combined with elastomeric properties gained through enzymatic crosslinking of the protein. Postprocessing via methanol and autoclaving provided tunable control of fiber features. Mechanical, optical, and chemical analyses demonstrated control of fiber properties by exploiting the physical cross-links, and generating double network hydrogels consisting of chemical and physical cross-links. Structure and chemical analyses revealed crystallinity from 30 to 50%, modulus from 0.5 to 4 MPa, and ultimate strength 1-5 MPa depending on the processing method. Fabrication and postprocessing combined provided fibers with extensibility from 100 to 400% ultimate strain. Fibers strained to 100% exhibited fourth order birefringence, revealing macroscopic orientation driven by chain mobility. The physical cross-links were influenced in part by the drying rate of fabricated materials, where bound water, packing density, and microstructural homogeneity influenced cross-linking efficiency. The ability to generate robust and versatile hydrogel microfibers is desirable for bottom-up assembly of biological tissues and for broader biomaterial applications. © 2017 Wiley Periodicals, Inc.

  4. SILK FIBRE DEGRADATION AND ANALYSIS BY PROTEOMICS

    Directory of Open Access Journals (Sweden)

    YUKSELOGLU S.Muge

    2016-05-01

    Full Text Available Silk is one of the promising natural fibres and has a long established history in textile production throughout the centuries. Silk is produced by cultured silk worms, spiders, scorpions, mites and flies. It is extracellular proteinaceous fibres which consist of highly crystalline and insoluble proteins, the fibroins glued with sericin and an amourphous protein. On the other hand, understanding and controlling the degradation of protein materials are important for determining quality and the value of appearance retention in textiles. Hence, for silk textiles, appearance retention is critical value for the quality. And this is one of the key properties directly related to the degree and nature of protein degradation. It is therefore necessary to understand the silk composition and damage to obtain good conservation treatments and long-term preservation especially for the historical silk fabrics. In this study, silk fibre and its properties are briefly introduced along with images on their fibre damages. Additionally, proteomics method which helps to understand the degradation at the molecular level in textiles is introduced. Finally, proteomic evaluation of silk is summarized according to the researchers carried out in the literature.

  5. Morphological and functional diversity of minor ampullate glands in spiders from the superfamily Amaurobioidea (Entelegynae: RTA clade)

    Czech Academy of Sciences Publication Activity Database

    Řezáč, M.; Krejčí, T.; Goodacre, S.L.; Haddad, C. R.; Řezáčová, Veronika

    2017-01-01

    Roč. 45, č. 2 (2017), s. 198-208 ISSN 0161-8202 Institutional support: RVO:61388971 Keywords : Cribellate capturing threads * major ampullate * silk glands Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 0.988, year: 2016

  6. Silkworms transformed with chimeric silkworm/spider silk genes spin composite silk fibers with improved mechanical properties

    Science.gov (United States)

    The development of a spider silk manufacturing process is of great interest. piggyBac vectors were used to create transgenic silkworms encoding chimeric silkworm/spider silk proteins. The silk fibers produced by these animals were composite materials that included chimeric silkworm/spider silk prote...

  7. Insecticide Resistance in Eggs and First Instars of the Bed Bug, Cimex lectularius (Hemiptera: Cimicidae

    Directory of Open Access Journals (Sweden)

    Brittany E. Campbell

    2015-01-01

    Full Text Available Two strains of the common bed bug, Cimex lectularius L., eggs and first instars collected from pyrethroid-resistant adults were evaluated for insecticide resistance and compared to a susceptible strain. Dose-response bioassays were conducted using two insecticide formulations (Temprid: imidacloprid/β-cyfluthrin, and Transport: acetamiprid/ bifenthrin. The lethal concentration (LC50 for the two resistant egg strains exposed to imidacloprid/β-cyfluthrin ranged from 3 to 5-fold higher than susceptible strain eggs. Resistant strain eggs dipped into formulations of acetamiprid/bifenthrin had LC50 values which were significantly greater (39 to 1,080-fold than susceptible strain eggs. Similar to eggs, resistant strain first instars exposed to residual applications of imidacloprid/β-cyfluthrin had LC50 values ranging from 121 to 493-fold greater than susceptible strain first instars. When resistant strain first instars were treated with acetamiprid/bifenthrin, they had LC50 values that were 99 to >1,900-fold greater than susceptible strain first instars. To determine differences between egg and first instar resistance, stage resistance ratios (SRR were compared between the two stages. There was little difference between the egg and first instar stages, indicated by small SRR values ranging from 1.1 to 10.0. This study suggests that insecticide resistance is expressed early during bed bug development.

  8. Valve spindle gland

    International Nuclear Information System (INIS)

    Burda, Z.; Harazim, A.; Kerlin, K.

    1979-01-01

    A gland is proposed of the valve spindle designed for radioactive or otherwise harmful media, such as in nuclear power plant primary circuits. The gland is installed in the valve cover and consists of a primary and a secondary part and of a gland case partitioning the gland space into two chambers. The bottom face of the gland case is provided with a double-sided collar for controlling the elements of the bottom primary gland while the top face is provided with a removable flange. (M.S.)

  9. File list: Oth.Lar.10.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Lar.10.AllAg.3rd_instar dm3 TFs and others Larvae 3rd instar SRX104963,SRX10497...4971,SRX331403 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.Lar.10.AllAg.3rd_instar.bed ...

  10. File list: Oth.Lar.20.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Lar.20.AllAg.3rd_instar dm3 TFs and others Larvae 3rd instar SRX318781,SRX31878...1403,SRX495243 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.Lar.20.AllAg.3rd_instar.bed ...

  11. File list: Unc.Lar.10.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  12. File list: His.Lar.10.AllAg.2nd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: InP.Lar.20.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.20.AllAg.3rd_instar dm3 Input control Larvae 3rd instar SRX467108,SRX287726...67103,SRX288024,SRX288023,SRX104976,SRX016172,SRX467107,SRX016173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.20.AllAg.3rd_instar.bed ...

  14. File list: His.Lar.05.AllAg.1st_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.05.AllAg.1st_instar dm3 Histone Larvae 1st instar SRX013088,SRX013009,SRX01...3064,SRX013044,SRX013097 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.05.AllAg.1st_instar.bed ...

  15. File list: His.Lar.05.AllAg.2nd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  16. File list: Pol.Lar.10.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Lar.10.AllAg.3rd_instar dm3 RNA polymerase Larvae 3rd instar SRX287908,SRX28790...7,SRX013070,SRX013082 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Pol.Lar.10.AllAg.3rd_instar.bed ...

  17. File list: ALL.Lar.05.AllAg.2nd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.05.AllAg.2nd_instar dm3 All antigens Larvae 2nd instar SRX013087,SRX013096,...SRX013043,SRX013015,SRX013112,SRX013042,SRX013113,SRX013016,SRX013114 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.05.AllAg.2nd_instar.bed ...

  18. File list: InP.Lar.10.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.10.AllAg.3rd_instar dm3 Input control Larvae 3rd instar SRX016172,SRX016173...87701,SRX287922,SRX467104,SRX287918,SRX287718,SRX104976,SRX467107 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.10.AllAg.3rd_instar.bed ...

  19. File list: ALL.Lar.10.AllAg.1st_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.10.AllAg.1st_instar dm3 All antigens Larvae 1st instar SRX013088,SRX013064,...SRX013044,SRX013009,SRX013072,SRX013097,SRX013055,SRX013056 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.10.AllAg.1st_instar.bed ...

  20. File list: ALL.Lar.50.AllAg.1st_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.50.AllAg.1st_instar dm3 All antigens Larvae 1st instar SRX013009,SRX013072,...SRX013088,SRX013044,SRX013064,SRX013097,SRX013056,SRX013055 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.50.AllAg.1st_instar.bed ...

  1. File list: His.Lar.20.AllAg.1st_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.20.AllAg.1st_instar dm3 Histone Larvae 1st instar SRX013009,SRX013088,SRX01...3044,SRX013064,SRX013097 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.20.AllAg.1st_instar.bed ...

  2. File list: ALL.Lar.20.AllAg.1st_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.20.AllAg.1st_instar dm3 All antigens Larvae 1st instar SRX013009,SRX013072,...SRX013088,SRX013044,SRX013064,SRX013097,SRX013055,SRX013056 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.20.AllAg.1st_instar.bed ...

  3. File list: ALL.Lar.05.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.05.AllAg.3rd_instar dm3 All antigens Larvae 3rd instar SRX104964,SRX104963,...SRX287718,SRX331401,SRX287658,SRX331366,SRX287906,SRX287678 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.05.AllAg.3rd_instar.bed ...

  4. File list: Pol.Lar.50.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Lar.50.AllAg.3rd_instar dm3 RNA polymerase Larvae 3rd instar SRX287908,SRX28790...7,SRX013070,SRX013082 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Pol.Lar.50.AllAg.3rd_instar.bed ...

  5. File list: ALL.Lar.50.AllAg.2nd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.50.AllAg.2nd_instar dm3 All antigens Larvae 2nd instar SRX013015,SRX013042,...SRX013112,SRX013016,SRX013114,SRX013043,SRX013087,SRX013096,SRX013113 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.50.AllAg.2nd_instar.bed ...

  6. File list: ALL.Lar.20.AllAg.2nd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.20.AllAg.2nd_instar dm3 All antigens Larvae 2nd instar SRX013015,SRX013042,...SRX013112,SRX013043,SRX013016,SRX013114,SRX013096,SRX013087,SRX013113 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.20.AllAg.2nd_instar.bed ...

  7. File list: ALL.Lar.50.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.50.AllAg.3rd_instar dm3 All antigens Larvae 3rd instar SRX1038029,SRX103803...SRX467060,SRX495306,SRX013058 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.50.AllAg.3rd_instar.bed ...

  8. File list: Unc.Lar.20.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Lar.20.AllAg.3rd_instar dm3 Unclassified Larvae 3rd instar SRX1038029,SRX103803...1,SRX1038032,SRX1038030,SRX022335,SRX032124,SRX022334,SRX032123,SRX013058 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Lar.20.AllAg.3rd_instar.bed ...

  9. File list: Pol.Lar.05.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Lar.05.AllAg.3rd_instar dm3 RNA polymerase Larvae 3rd instar SRX287907,SRX28790...8,SRX013070,SRX013082 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Pol.Lar.05.AllAg.3rd_instar.bed ...

  10. File list: His.Lar.50.AllAg.1st_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.50.AllAg.1st_instar dm3 Histone Larvae 1st instar SRX013009,SRX013088,SRX01...3044,SRX013064,SRX013097 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.50.AllAg.1st_instar.bed ...

  11. File list: ALL.Lar.10.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  12. File list: His.Lar.50.AllAg.2nd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: His.Lar.20.AllAg.2nd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.20.AllAg.2nd_instar dm3 Histone Larvae 2nd instar SRX013015,SRX013042,SRX01...3112,SRX013043,SRX013096,SRX013087 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.20.AllAg.2nd_instar.bed ...

  14. File list: ALL.Lar.20.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.20.AllAg.3rd_instar dm3 All antigens Larvae 3rd instar SRX1038029,SRX103803...SRX013082,SRX467107,SRX016173,SRX215499,SRX495243,SRX013058 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.20.AllAg.3rd_instar.bed ...

  15. File list: Unc.Lar.05.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Lar.05.AllAg.3rd_instar dm3 Unclassified Larvae 3rd instar SRX1038031,SRX103802...9,SRX1038032,SRX1038030,SRX022335,SRX022334,SRX032124,SRX013058,SRX032123 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Lar.05.AllAg.3rd_instar.bed ...

  16. File list: His.Lar.10.AllAg.1st_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.10.AllAg.1st_instar dm3 Histone Larvae 1st instar SRX013088,SRX013064,SRX01...3044,SRX013009,SRX013097 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.10.AllAg.1st_instar.bed ...

  17. File list: Pol.Lar.20.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Lar.20.AllAg.3rd_instar dm3 RNA polymerase Larvae 3rd instar SRX287908,SRX28790...7,SRX013070,SRX013082 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Pol.Lar.20.AllAg.3rd_instar.bed ...

  18. File list: ALL.Lar.05.AllAg.1st_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.05.AllAg.1st_instar dm3 All antigens Larvae 1st instar SRX013088,SRX013009,...SRX013064,SRX013044,SRX013072,SRX013055,SRX013097,SRX013056 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.05.AllAg.1st_instar.bed ...

  19. File list: InP.Lar.05.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.05.AllAg.3rd_instar dm3 Input control Larvae 3rd instar SRX016173,SRX288024...87921,SRX287718,SRX331401,SRX287658,SRX331366,SRX287906,SRX287678 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.05.AllAg.3rd_instar.bed ...

  20. File list: Oth.Lar.05.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Lar.05.AllAg.3rd_instar dm3 TFs and others Larvae 3rd instar SRX104964,SRX10496...1403,SRX495243 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.Lar.05.AllAg.3rd_instar.bed ...

  1. File list: Unc.Lar.50.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Lar.50.AllAg.3rd_instar dm3 Unclassified Larvae 3rd instar SRX1038029,SRX103803...1,SRX1038032,SRX1038030,SRX022335,SRX032124,SRX032123,SRX013058 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Lar.50.AllAg.3rd_instar.bed ...

  2. File list: InP.Lar.50.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.50.AllAg.3rd_instar dm3 Input control Larvae 3rd instar SRX287726,SRX331369...87917,SRX287921,SRX288023,SRX467107,SRX016172,SRX016173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.50.AllAg.3rd_instar.bed ...

  3. File list: Oth.Lar.50.AllAg.3rd_instar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Lar.50.AllAg.3rd_instar dm3 TFs and others Larvae 3rd instar SRX318781,SRX31878...5306 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.Lar.50.AllAg.3rd_instar.bed ...

  4. Silk-Silk Interactions between Silkworm Fibroin and Recombinant Spider Silk Fusion Proteins Enable the Construction of Bioactive Materials.

    Science.gov (United States)

    Nilebäck, Linnea; Chouhan, Dimple; Jansson, Ronnie; Widhe, Mona; Mandal, Biman B; Hedhammar, My

    2017-09-20

    Natural silk is easily accessible from silkworms and can be processed into different formats suitable as biomaterials and cell culture matrixes. Recombinant DNA technology enables chemical-free functionalization of partial silk proteins through fusion with peptide motifs and protein domains, but this constitutes a less cost-effective production process. Herein, we show that natural silk fibroin (SF) can be used as a bulk material that can be top-coated with a thin layer of the recombinant spider silk protein 4RepCT in fusion with various bioactive motifs and domains. The coating process is based on a silk assembly to achieve stable interactions between the silk types under mild buffer conditions. The assembly process was studied in real time by quartz crystal microbalance with dissipation. Coatings, electrospun mats, and microporous scaffolds were constructed from Antheraea assama and Bombyx mori SFs. The morphology of the fibroin materials before and after coating with recombinant silk proteins was analyzed by scanning electron microscopy and atomic force microscopy. SF materials coated with various bioactive 4RepCT fusion proteins resulted in directed antibody capture, enzymatic activity, and improved cell attachment and spreading, respectively, compared to pristine SF materials. The herein-described procedure allows a fast and easy route for the construction of bioactive materials.

  5. Buyid Silk and the Tale of Bibi Shahrbanu: Identification of Biomarkers of Artificial Aging (Forgery) of Silk.

    Science.gov (United States)

    Moini, Mehdi; Rollman, Christopher M

    2017-10-03

    Buyid silk forgery is one of the most famous silk forgeries in the world. In 1924-1925, excavation of the Bibi Shahrbanu site in Iran unearthed several silk textiles. The silks were thought to be of the Buyid period (934-1062 BCE) of the Persian Empire and have since been known as the "Buyid silks". In the 1930s, more silk appeared and was reported as being from the Buyid period as well. Controversy over the authenticity of these silks escalated after the purchase of the silks by museums throughout the world. Extensive investigations of several of these silks have been conducted over the years with respect to iconography, weaving patterns, dyes/mordant, style, and even radiocarbon dating. It was found that most of the silks are not from Buyid period. To test the authenticity of these silk fabrics, the recently developed silk dating technique using amino acid racemization (AAR) in conjunction with capillary electrophoresis mass spectrometry was applied to 13 Buyid silk specimens from the Textile Museum collections. Among these silk specimens, the AAR ratios of only one specimen were consistent with authentic silk fabrics collected from various museums. In addition, the aspartic acid racemization ratio of this specimen was also consistent with its 14 C dating. The other "Buyid silks" showed excessive levels of amino acid racemization not only for aspartic acid, but also for phenylalanine and tyrosine, inconsistent with racemization rates of these amino acids in authentic historical silk fabrics. Treatment of modern silk with a base at different pH and temperature reproduced the AAR pattern of the Buyid silks, implying that chemical treatment with a base at relatively high temperatures was perhaps the method used to artificially age these fabrics. The results imply that the racemization ratios of aspartic acid, phenylalanine, and tyrosine can be used as biomarkers for identification of naturally versus artificially aged silk.

  6. Adrenal Gland Cancer

    Science.gov (United States)

    ... either benign or malignant. Benign tumors aren't cancer. Malignant ones are. Most adrenal gland tumors are ... and may not require treatment. Malignant adrenal gland cancers are uncommon. Types of tumors include Adrenocortical carcinoma - ...

  7. Production of silk sericin/silk fibroin blend nanofibers

    Directory of Open Access Journals (Sweden)

    Zhang Xianhua

    2011-01-01

    Full Text Available Abstract Silk sericin (SS/silk fibroin (SF blend nanofibers have been produced by electrospinning in a binary SS/SF trifluoroacetic acid (TFA solution system, which was prepared by mixing 20 wt.% SS TFA solution and 10 wt.% SF TFA solution to give different compositions. The diameters of the SS/SF nanofibers ranged from 33 to 837 nm, and they showed a round cross section. The surface of the SS/SF nanofibers was smooth, and the fibers possessed a bead-free structure. The average diameters of the SS/SF (75/25, 50/50, and 25/75 blend nanofibers were much thicker than that of SS and SF nanofibers. The SS/SF (100/0, 75/25, and 50/50 blend nanofibers were easily dissolved in water, while the SS/SF (25/75 and 0/100 blend nanofibers could not be completely dissolved in water. The SS/SF blend nanofibers could not be completely dissolved in methanol. The SS/SF blend nanofibers were characterized by Fourier transform infrared (FTIR spectroscopy, differential scanning calorimetry, and differential thermal analysis. FTIR showed that the SS/SF blend nanofibers possessed a random coil conformation and ß-sheet structure.

  8. Silk Electrogel Based Gastroretentive Drug Delivery System

    Science.gov (United States)

    Wang, Qianrui

    Gastric cancer has become a global pandemic and there is imperative to develop efficient therapies. Oral dosing strategy is the preferred route to deliver drugs for treating the disease. Recent studies suggested silk electro hydrogel, which is pH sensitive and reversible, has potential as a vehicle to deliver the drug in the stomach environment. The aim of this study is to establish in vitro electrogelation e-gel based silk gel as a gastroretentive drug delivery system. We successfully extended the duration of silk e-gel in artificial gastric juice by mixing silk solution with glycerol at different ratios before the electrogelation. Structural analysis indicated the extended duration was due to the change of beta sheet content. The glycerol mixed silk e-gel had good doxorubicin loading capability and could release doxorubicin in a sustained-release profile. Doxorubicin loaded silk e-gels were applied to human gastric cancer cells. Significant cell viability decrease was observed. We believe that with further characterization as well as functional analysis, the silk e-gel system has the potential to become an effective vehicle for gastric drug delivery applications.

  9. Effect of electronic beam irradiation on last instar larvae of lasioderma serricorne fabricius

    International Nuclear Information System (INIS)

    Chen Yuntang; Guo Dongquan; Lu Xiaohua; Zhang Jianwei; Yang Baoan; Du Yueguang; Liu Jiangyu; Tian Zhanjun; Zhang Xiaoyan

    2010-01-01

    The electronic beam irradiation effects on the last instar larvae of cigarette beetle (Lasioderma serricorne Fabricius) in tobacco were studied, and the mortality in 42 days, lethal time, pupation rate, emergence rate and reproductive capacity after irradiation were measured. The results showed that the mortality increased with the increase of irradiation dosage, but the larvae did not dead immediately. The last instar larvae irradiated by the dosages higher than 480 Gy could prevent the development of larvae to adults. No new generation was found after 300 Gy treatment of the last instar larvae. So 300 Gy irradiation could be considered as a suitable dose to prevent the reproduction of cigarette beetle of the last instar larvae in the tobacco. (authors)

  10. Spider Silk Fibers Spun from Soluble Recombinant Silk Produced in Mammalian Cells

    Science.gov (United States)

    Lazaris, Anthoula; Arcidiacono, Steven; Huang, Yue; Zhou, Jiang-Feng; Duguay, François; Chretien, Nathalie; Welsh, Elizabeth A.; Soares, Jason W.; Karatzas, Costas N.

    2002-01-01

    Spider silks are protein-based ``biopolymer'' filaments or threads secreted by specialized epithelial cells as concentrated soluble precursors of highly repetitive primary sequences. Spider dragline silk is a flexible, lightweight fiber of extraordinary strength and toughness comparable to that of synthetic high-performance fibers. We sought to ``biomimic'' the process of spider silk production by expressing in mammalian cells the dragline silk genes (ADF-3/MaSpII and MaSpI) of two spider species. We produced soluble recombinant (rc)-dragline silk proteins with molecular masses of 60 to 140 kilodaltons. We demonstrated the wet spinning of silk monofilaments spun from a concentrated aqueous solution of soluble rc-spider silk protein (ADF-3; 60 kilodaltons) under modest shear and coagulation conditions. The spun fibers were water insoluble with a fine diameter (10 to 40 micrometers) and exhibited toughness and modulus values comparable to those of native dragline silks but with lower tenacity. Dope solutions with rc-silk protein concentrations >20% and postspinning draw were necessary to achieve improved mechanical properties of the spun fibers. Fiber properties correlated with finer fiber diameter and increased birefringence.

  11. Uncovering the structure-function relationship in spider silk

    Science.gov (United States)

    Yarger, Jeffery L.; Cherry, Brian R.; van der Vaart, Arjan

    2018-03-01

    All spiders produce protein-based biopolymer fibres that we call silk. The most studied of these silks is spider dragline silk, which is very tough and relatively abundant compared with other types of spider silks. Considerable research has been devoted to understanding the relationship between the molecular structure and mechanical properties of spider dragline silks. In this Review, we overview experimental and computational studies that have provided a wealth of detail at the molecular level on the highly conserved repetitive core and terminal regions of spider dragline silk. We also discuss the role of the nanocrystalline β-sheets and amorphous regions in determining the properties of spider silk fibres, endowing them with strength and elasticity. Additionally, we outline imaging techniques and modelling studies that elucidate the importance of the hierarchical structure of silk fibres at the molecular level. These insights into structure-function relationships can guide the reverse engineering of spider silk to enable the production of superior synthetic fibres.

  12. Dermatologic Diseases in Silk Workers

    Directory of Open Access Journals (Sweden)

    J S Pasricha

    1985-01-01

    Full Text Available A survey of 112 workers of a silk facory near Bangalore, for dermatologic diseases revealed (1 a characteristic wearing off of the medial halves of the distal free edges of the finger nail plates in 10 of the 15 cocoonsorters, (2 maceration of the palms in 58 workers of the boiling and reeling section, and (3 pitted keratolysis of the palms, in 42 workers, also from the boiling and reeling section. There was no clinical evidence of contact dermatitis, and patch tests with the silk thread from the cocoons in 25 workers showed a very mild reaction in 2 workers and a doubtful reaction in another two. In addition, one worker from the skeining section had crisscross superficial fissures on the finger tips caused by friction, two workers had paronychia ′of the fingers and four workers had dermatophytFNx01t fingers webs. As in the previous survey, these workers also had a high incidence of ichthyosis (92 workers and hyperketatosis of the palms (62 workers and soles (110 workers.

  13. Defensive behavior associated with secretions from the prosternal paired glands of the larvae of Heliconius erato phyllis Fabricius (Lepidoptera, Nymphalidae

    Directory of Open Access Journals (Sweden)

    Eliane de Oliveira Borges

    2014-06-01

    Full Text Available Defensive behavior associated with secretions from the prosternal paired glands of the larvae of Heliconius erato phyllis Fabricius (Lepidoptera, Nymphalidae. Our work presents for the first time, the defensive behavior associated with the release of the product of the prosternal paired glands of the larva of Heliconius erato phyllis Fabricius, 1775 (Lepidoptera, Nymphalidae, Heliconiinae. The prosternal glands were first described for larvae of H. erato phyllis. They are formed by two types of glandular structures: the impair gland and the paired glands. The prosternal glands are located within the conical integumentary sac, which in turn is situated on the individual's prosternum. The main goal of this study is to analyze the existence of any secretion from the prosternal paired glands, and check the action mode of this secretion. The methodology used for chemical analysis of the glands included the aeration and, analysis in gas chromatography and gas chromatography-mass spectrometry. The results show that the prosternal glands do not produce volatiles. Bioassays were conducted with simulated and natural attacks and revealed that the prosternal paired glands produce secretions of defense together with silk produced by labials glands as a defense strategy, described for the first time, against ants. The strategy consists in wrapping the ant with silk threads, the entire wrapped object moved to the end of the body, with the aid of the legs and prolegs, and possibly fixed in a nearby place. Evidence for the existence of a conical integumentary sac in larvae of other species and families of Lepidoptera allows us to propose the possibility of occurrence of prosternal paired glands with defensive function in these other groups as well.

  14. Intra-instar larval cannibalism in Anopheles gambiae (s.s.) and Anopheles stephensi (Diptera: Culicidae).

    Science.gov (United States)

    Porretta, Daniele; Mastrantonio, Valentina; Crasta, Graziano; Bellini, Romeo; Comandatore, Francesco; Rossi, Paolo; Favia, Guido; Bandi, Claudio; Urbanelli, Sandra

    2016-11-02

    Cannibalism has been observed in a wide range of animal taxa and its importance in persistence and stability of populations has been documented. In anopheline malaria vectors the inter-instar cannibalism between fourth- and first-instar larvae (L4-L1) has been shown in several species, while intra-instar cannibalism remains poorly investigated. In this study we tested the occurrence of intra-instar cannibalism within larvae of second-, third- and fourth-instar (L2, L3 and L4) of Anopheles gambiae (s.s.) and An. stephensi. Experiments were set up under laboratory conditions and the effects of larval density, duration of the contact period among larvae and the presence of an older larva (i.e. a potential cannibal of bigger size) on cannibalism rate were analysed. Cannibalism was assessed by computing the number of missing larvae after 24 and 48 h from the beginning of the experiments and further documented by records with a GoPro videocamera. Intra-instar cannibalism was observed in all larval instars of both species with higher frequency in An. gambiae (s.s.) than in An. stephensi. In both species the total number of cannibalistic events increased from 0-24 to 0-48 h. The density affected the cannibalism rate, but its effect was related to the larval instar and to the presence of older larvae. Interestingly, the lower cannibalism rate between L4 larvae was observed at the highest density and the cannibalism rate between L3 larvae decreased when one L4 was added. The present study provides experimental evidence of intra-instar cannibalism in the malaria vectors An. gambiae (s.s.) and An. stephensi and highlights the possible occurrence of complex interactions between all larval instars potentially present in the breeding sites. We hypothesize that the high density and the presence of a potential cannibal of bigger size could affect the readiness to attack conspecifics, resulting into low risk larval behavior and lower cannibalism rate. The understanding of

  15. Intra-instar larval cannibalism in Anopheles gambiae (s.s. and Anopheles stephensi (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Daniele Porretta

    2016-11-01

    Full Text Available Abstract Background Cannibalism has been observed in a wide range of animal taxa and its importance in persistence and stability of populations has been documented. In anopheline malaria vectors the inter-instar cannibalism between fourth- and first-instar larvae (L4-L1 has been shown in several species, while intra-instar cannibalism remains poorly investigated. In this study we tested the occurrence of intra-instar cannibalism within larvae of second-, third- and fourth-instar (L2, L3 and L4 of Anopheles gambiae (s.s. and An. stephensi. Experiments were set up under laboratory conditions and the effects of larval density, duration of the contact period among larvae and the presence of an older larva (i.e. a potential cannibal of bigger size on cannibalism rate were analysed. Cannibalism was assessed by computing the number of missing larvae after 24 and 48 h from the beginning of the experiments and further documented by records with a GoPro videocamera. Results Intra-instar cannibalism was observed in all larval instars of both species with higher frequency in An. gambiae (s.s. than in An. stephensi. In both species the total number of cannibalistic events increased from 0–24 to 0–48 h. The density affected the cannibalism rate, but its effect was related to the larval instar and to the presence of older larvae. Interestingly, the lower cannibalism rate between L4 larvae was observed at the highest density and the cannibalism rate between L3 larvae decreased when one L4 was added. Conclusions The present study provides experimental evidence of intra-instar cannibalism in the malaria vectors An. gambiae (s.s. and An. stephensi and highlights the possible occurrence of complex interactions between all larval instars potentially present in the breeding sites. We hypothesize that the high density and the presence of a potential cannibal of bigger size could affect the readiness to attack conspecifics, resulting into low risk larval behavior

  16. Manufacture and Drug Delivery Applications of Silk Nanoparticles.

    Science.gov (United States)

    Wongpinyochit, Thidarat; Johnston, Blair F; Seib, F Philipp

    2016-10-08

    Silk is a promising biopolymer for biomedical and pharmaceutical applications due to its outstanding mechanical properties, biocompatibility and biodegradability, as well its ability to protect and subsequently release its payload in response to a trigger. While silk can be formulated into various material formats, silk nanoparticles are emerging as promising drug delivery systems. Therefore, this article covers the procedures for reverse engineering silk cocoons to yield a regenerated silk solution that can be used to generate stable silk nanoparticles. These nanoparticles are subsequently characterized, drug loaded and explored as a potential anticancer drug delivery system. Briefly, silk cocoons are reverse engineered first by degumming the cocoons, followed by silk dissolution and clean up, to yield an aqueous silk solution. Next, the regenerated silk solution is subjected to nanoprecipitation to yield silk nanoparticles - a simple but powerful method that generates uniform nanoparticles. The silk nanoparticles are characterized according to their size, zeta potential, morphology and stability in aqueous media, as well as their ability to entrap a chemotherapeutic payload and kill human breast cancer cells. Overall, the described methodology yields uniform silk nanoparticles that can be readily explored for a myriad of applications, including their use as a potential nanomedicine.

  17. Radiation degradation of silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Wachiraporn Pewlong; Boonya Sudatis [Office of Atomic Energy for Peace, Bangkok (Thailand); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-09-01

    Silk fibroin fiber from the domesticated silkworm Bombyx mori was irradiated in the dose range up to 2500 kGy using an electron beam accelerator to apply the radiation degradation technique as a means to solubilize fibroin. The tensile strength of irradiated fibroin fiber decreased with increasing dose and the presence of oxygen in the irradiation atmosphere enhanced the degradation. The solubilization of irradiated fibroin fiber was evaluated using the following three kinds of solutions: calcium chloride solution (CaCl{sub 2}/C{sub 2}H{sub 5}OH/H{sub 2}O = 1 : 2 : 8 in mole ratio), hydrochloric acid (0.5N) and distilled water. Dissolution of fibroin fiber into these solutions was significantly enhanced by irradiation. Especially, an appreciable amount of water-soluble protein was extracted by distilled water. (author)

  18. Radiation degradation of silk protein

    International Nuclear Information System (INIS)

    Pewlong, W.; Sudatis, B.; Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu

    2000-01-01

    Silk fibroin fiber from the domesticated silkworm Bombyx mori was irradiated using an electron beam accelerator to investigate the application of the radiation degradation technique as a means to solubilize fibroin. The irradiation caused a significant degradation of the fiber. The tensile strength of fibroin fiber irradiated up to 2500 kGy decreased rapidly with increasing dose. The presence of oxygen in the irradiation atmosphere enhanced degradation of the tensile strength. The solubilization of irradiated fibroin fiber was evaluated using the following three kinds of solutions: a calcium chloride solution(CaCl 2 /C 2 H 5 OH/H 2 O=1:2:8 in mole ratio), a hydrochloric acid (0.5 N) and a distilled water. Dissolution of fibroin fiber into these solutions was significantly enhanced by irradiation. Especially, an appreciable amount of water soluble proteins was extracted by a distilled water. (author)

  19. Radiation degradation of silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Pewlong, W; Sudatis, B [Office of Atomic Energy for Peace, Bangkok (Thailand); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Silk fibroin fiber from the domesticated silkworm Bombyx mori was irradiated using an electron beam accelerator to investigate the application of the radiation degradation technique as a means to solubilize fibroin. The irradiation caused a significant degradation of the fiber. The tensile strength of fibroin fiber irradiated up to 2500 kGy decreased rapidly with increasing dose. The presence of oxygen in the irradiation atmosphere enhanced degradation of the tensile strength. The solubilization of irradiated fibroin fiber was evaluated using the following three kinds of solutions: a calcium chloride solution(CaCl{sub 2}/C{sub 2}H{sub 5}OH/H{sub 2}O=1:2:8 in mole ratio), a hydrochloric acid (0.5 N) and a distilled water. Dissolution of fibroin fiber into these solutions was significantly enhanced by irradiation. Especially, an appreciable amount of water soluble proteins was extracted by a distilled water. (author)

  20. Facts and myths of antibacterial properties of silk.

    Science.gov (United States)

    Kaur, Jasjeet; Rajkhowa, Rangam; Afrin, Tarannum; Tsuzuki, Takuya; Wang, Xungai

    2014-03-01

    Silk cocoons provide protection to silkworm from biotic and abiotic hazards during the immobile pupal phase of the lifecycle of silkworms. Protection is particularly important for the wild silk cocoons reared in an open and harsh environment. To understand whether some of the cocoon components resist growth of microorganisms, in vitro studies were performed using gram negative bacteria Escherichia coli (E. coli) to investigate antibacterial properties of silk fiber, silk gum, and calcium oxalate crystals embedded inside some cocoons. The results show that the previously reported antibacterial properties of silk cocoons are actually due to residues of chemicals used to isolate/purify cocoon elements, and properly isolated silk fiber, gum, and embedded crystals free from such residues do not have inherent resistance to E. coli. This study removes the uncertainty created by previous studies over the presence of antibacterial properties of silk cocoons, particularly the silk gum and sericin. Copyright © 2013 Wiley Periodicals, Inc.

  1. Structural analysis and application to biomaterials of the silk fibroins

    International Nuclear Information System (INIS)

    Nakazawa, Yasumoto

    2010-01-01

    Silk fibroin from Bombyx mori silkworm has outstanding mechanical properties despite being spun from aqueous solution. I have clarified two distinct structures in the solid state; silk I and silk II, which mean the structures before and after spinning, by using solid state NMR. Moreover, I have been developing several kinds of biomaterials, such as bone regeneration materials and vascular grafts. In this paper, I present two topics: one is the structural analyses of the silk fibroin in detail, the other is applications of silk fibroins to tissue engineering. In the case of vascular regeneration, I have developed the small diameter vascular grafts made by silk fibroins. The new grafts from silk fibroins have good patency, and these grafts were commonly covered with cells and platelets at 4 weeks after implantation. For bone tissue engineering, I performed structural analyses of a new silk-like peptide, E n (AGSGAG) 4 , in order to consider the molecular design of biomaterials for bone regeneration. (author)

  2. Protective effects of flavonoids from corn silk on oxidative stress ...

    African Journals Online (AJOL)

    Protective effects of flavonoids from corn silk on oxidative stress induced by ... The present study aims at exploring the effects of flavonoids from corn silk (FCS) on oxidative stress induced by exhaustive exercise in mice. ... from 32 Countries:.

  3. Gamma radiation effects of {sup 60} Co on Bombyx mori (Lep., Bombycidae) modifying the silk fiber production; Influencia da radiacao gama ({sup 60} Co) na producao de fios de seda em Bombyx mori(Lep.,Bombycidae)

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro Junior, Francisco [Universidade Metodista de Piracicaba (UNIMEP), SP (Brazil); Bendassolli, Jose A. [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)

    1997-12-01

    The present work aimed to verify the biological effects of the application of different doses of gamma radiation during the fifth instar of the silkworm catepillar. Sevently eight silkworm caterpillars (Bombyx mori) were irradiated with {gamma}{sup 60} Co radiation at the initial period of the fifth instar. The caterpillars were divided and classified in six batches of thirteen individuals each. Treatments 1 through 5 received 20, 40, 60, 80 and 100 Gy, respectively, and the control, also consisted of thirteen caterpillars, was not irradiated. The results showed a general increase in the silk fiber content in the irradiated batches compared to the control. The weight of the silk cocoons was higher with increasing doses of irradiation, from 20 to 80 Gy, respectively, followed by a decrease in weight in the treatment irradiated with 100 Gy. the results obtained in this experiment enable the conclusion that the radiation applied to the caterpillars significantly influenced the production of silk fiber in this species. (author). 4 refs., 2 figs., 3 tabs.

  4. Quantitative analysis of allantoin in Iranian corn silk

    OpenAIRE

    E. Khanpour*; M. Modarresi

    2017-01-01

    Background and objectives: Zea mays is cultivated in different parts of Iran and corn silk is used in traditional medicine. Allantoin is one of the major compounds in corn silk. The purpose of this research was the quantitatve analysis of allantoin in corn silks belonging to several regions of Iran. Methods: The samples of corn silk were prepared from three provinces of Iran (Kermanshah, Fars and Razavi Khorasan). The dried plant materials were infused in boiling distilled water with a temper...

  5. Immunohistochemical sweat gland profiles.

    Science.gov (United States)

    Noël, Fanchon; Piérard, Gérald E; Delvenne, Philippe; Quatresooz, Pascale; Humbert, Philippe; Piérard-Franchimont, Claudine

    2013-09-01

    Human sweat glands are heterogeneous in their structures and functions. Accordingly, eccrine, apocrine, and apoeccrine glands are distinguished. Some immunohistochemical markers are expected to distinguish the sweat gland types in their secretory and excretory parts. This study used two sets of antibodies. The first panel was composed of antibodies directed to well-defined sweat gland structures. The molecular targets included the low-molecular-weight cytokeratins CAM 5.2, the S100-B protein, the epithelial membrane antigen (EMA), the carcinoembryonic antigen (CEA), and the lectin Ulex europaeus agglutinin-1 (UEA-1). A second exploratory panel of antibodies targeted syndecan-1 (CD138), NKI-C3 (CD63), and CD68. They were used to disclose some undescribed antigen expressions in human sweat glands. The first set of antibodies confirmed previous findings. The immunoreactivities of the three sweat gland types were similar in the excretory ducts. By contrast, they were distinguished in the deeper coiled secretory portions of the glands. Clues supporting their distinction and probably their functional activity were obtained by immunohistochemistry using the S100-B protein, CEA and CD63 antibodies. The immunoreactivity to the S100-B protein, CEA and CD63 possibly help identifying apoeccrine sweat glands or a peculiar functional activity of eccrine sweat glands. © 2013 Wiley Periodicals, Inc.

  6. Polymorphic regenerated silk fibers assembled through bioinspired spinning.

    Science.gov (United States)

    Ling, Shengjie; Qin, Zhao; Li, Chunmei; Huang, Wenwen; Kaplan, David L; Buehler, Markus J

    2017-11-09

    A variety of artificial spinning methods have been applied to produce regenerated silk fibers; however, how to spin regenerated silk fibers that retain the advantages of natural silks in terms of structural hierarchy and mechanical properties remains challenging. Here, we show a bioinspired approach to spin regenerated silk fibers. First, we develop a nematic silk microfibril solution, highly viscous and stable, by partially dissolving silk fibers into microfibrils. This solution maintains the hierarchical structures in natural silks and serves as spinning dope. It is then spun into regenerated silk fibers by direct extrusion in the air, offering a useful route to generate polymorphic and hierarchical regenerated silk fibers with physical properties beyond natural fiber construction. The materials maintain the structural hierarchy and mechanical properties of natural silks, including a modulus of 11 ± 4 GPa, even higher than natural spider silk. It can further be functionalized with a conductive silk/carbon nanotube coating, responsive to changes in humidity and temperature.

  7. Nucleic acids levels in X-irradiated 5th instar nymphs of Dysdercus koenigii F

    International Nuclear Information System (INIS)

    Harwalkar, M.R.; Ramakrishnan, V.

    1993-01-01

    Irradiation of early 5th instar nymphs of Dysdercus koenigii F. with X-ray doses ranging from 10 to 70 Gy affected their metamorphosis in a dose dependent manner. At 70 Gy dose, metamorphosis of nymphs was completely inhibited although these nymphs survived for more than 10 days. In unirradiated 5th instar nymphs, DNA content doubled between 2nd and 3rd day and it remained at this level till these nymphs completed metamorphosis. However, DNA content of nymphs exposed to metamorphosis inhibition dose of 70 Gy X-rays showed only slight increase from 4th day and its profile remained at lower level throughout 5th instar nymphal period. Though the increase in RNA content in both the groups was found to be gradual upto 3rd day, the increase was more pronounced in case of unexposed insects. (author). 9 refs., 2 tabs

  8. Hybrid Silk Fibers Dry-Spun from Regenerated Silk Fibroin/Graphene Oxide Aqueous Solutions.

    Science.gov (United States)

    Zhang, Chao; Zhang, Yaopeng; Shao, Huili; Hu, Xuechao

    2016-02-10

    Regenerated silk fibroin (RSF)/graphene oxide (GO) hybrid silk fibers were dry-spun from a mixed dope of GO suspension and RSF aqueous solution. It was observed that the presence of GO greatly affect the viscosity of RSF solution. The RSF/GO hybrid fibers showed from FTIR result lower β-sheet content compared to that of pure RSF fibers. The result of synchrotron radiation wide-angle X-ray diffraction showed that the addition of GO confined the crystallization of silk fibroin (SF) leading to the decrease of crystallinity, smaller crystallite size, and new formation of interphase zones in the artificial silks. Synchrotron radiation small-angle X-ray scattering also proved that GO sheets in the hybrid silks and blended solutions were coated with a certain thickness of interphase zones due to the complex interaction between the two components. A low addition of GO, together with the mesophase zones formed between GO and RSF, enhanced the mechanical properties of hybrid fibers. The highest breaking stress of the hybrid fibers reached 435.5 ± 71.6 MPa, 23% improvement in comparison to that of degummed silk and 72% larger than that of pure RSF silk fiber. The hybrid RSF/GO materials with good biocompatibility and enhanced mechanical properties may have potential applications in tissue engineering, bioelectronic devices, or energy storage.

  9. Silk: a potential medium for tissue engineering.

    Science.gov (United States)

    Sobajo, Cassandra; Behzad, Farhad; Yuan, Xue-Feng; Bayat, Ardeshir

    2008-01-01

    Human skin is a complex bilayered organ that serves as a protective barrier against the environment. The loss of integrity of skin by traumatic experiences such as burns and ulcers may result in considerable disability or ultimately death. Therefore, in skin injuries, adequate dermal substitutes are among primary care targets, aimed at replacing the structural and functional properties of native skin. To date, there are very few single application tissue-engineered dermal constructs fulfilling this criterion. Silk produced by the domestic silkworm, Bombyx mori, has a long history of use in medicine. It has recently been increasingly investigated as a promising biomaterial for dermal constructs. Silk contains 2 fibrous proteins, sericin and fibroin. Each one exhibits unique mechanical and biological properties. Comprehensive review of randomized-controlled trials investigating current dermal constructs and the structures and properties of silk-based constructs on wound healing. This review revealed that silk-fibroin is regarded as the most promising biomaterial, providing options for the construction of tissue-engineered skin. The research available indicates that silk fibroin is a suitable biomaterial scaffold for the provision of adequate dermal constructs.

  10. Spinning Gland Transcriptomics from Two Main Clades of Spiders (Order: Araneae) - Insights on Their Molecular, Anatomical and Behavioral Evolution

    Science.gov (United States)

    Prosdocimi, Francisco; Bittencourt, Daniela; da Silva, Felipe Rodrigues; Kirst, Matias; Motta, Paulo C.; Rech, Elibio L.

    2011-01-01

    Characterized by distinctive evolutionary adaptations, spiders provide a comprehensive system for evolutionary and developmental studies of anatomical organs, including silk and venom production. Here we performed cDNA sequencing using massively parallel sequencers (454 GS-FLX Titanium) to generate ∼80,000 reads from the spinning gland of Actinopus spp. (infraorder: Mygalomorphae) and Gasteracantha cancriformis (infraorder: Araneomorphae, Orbiculariae clade). Actinopus spp. retains primitive characteristics on web usage and presents a single undifferentiated spinning gland while the orbiculariae spiders have seven differentiated spinning glands and complex patterns of web usage. MIRA, Celera Assembler and CAP3 software were used to cluster NGS reads for each spider. CAP3 unigenes passed through a pipeline for automatic annotation, classification by biological function, and comparative transcriptomics. Genes related to spider silks were manually curated and analyzed. Although a single spidroin gene family was found in Actinopus spp., a vast repertoire of specialized spider silk proteins was encountered in orbiculariae. Astacin-like metalloproteases (meprin subfamily) were shown to be some of the most sampled unigenes and duplicated gene families in G. cancriformis since its evolutionary split from mygalomorphs. Our results confirm that the evolution of the molecular repertoire of silk proteins was accompanied by the (i) anatomical differentiation of spinning glands and (ii) behavioral complexification in the web usage. Finally, a phylogenetic tree was constructed to cluster most of the known spidroins in gene clades. This is the first large-scale, multi-organism transcriptome for spider spinning glands and a first step into a broad understanding of spider web systems biology and evolution. PMID:21738742

  11. Spinning gland transcriptomics from two main clades of spiders (order: Araneae--insights on their molecular, anatomical and behavioral evolution.

    Directory of Open Access Journals (Sweden)

    Francisco Prosdocimi

    Full Text Available Characterized by distinctive evolutionary adaptations, spiders provide a comprehensive system for evolutionary and developmental studies of anatomical organs, including silk and venom production. Here we performed cDNA sequencing using massively parallel sequencers (454 GS-FLX Titanium to generate ∼80,000 reads from the spinning gland of Actinopus spp. (infraorder: Mygalomorphae and Gasteracantha cancriformis (infraorder: Araneomorphae, Orbiculariae clade. Actinopus spp. retains primitive characteristics on web usage and presents a single undifferentiated spinning gland while the orbiculariae spiders have seven differentiated spinning glands and complex patterns of web usage. MIRA, Celera Assembler and CAP3 software were used to cluster NGS reads for each spider. CAP3 unigenes passed through a pipeline for automatic annotation, classification by biological function, and comparative transcriptomics. Genes related to spider silks were manually curated and analyzed. Although a single spidroin gene family was found in Actinopus spp., a vast repertoire of specialized spider silk proteins was encountered in orbiculariae. Astacin-like metalloproteases (meprin subfamily were shown to be some of the most sampled unigenes and duplicated gene families in G. cancriformis since its evolutionary split from mygalomorphs. Our results confirm that the evolution of the molecular repertoire of silk proteins was accompanied by the (i anatomical differentiation of spinning glands and (ii behavioral complexification in the web usage. Finally, a phylogenetic tree was constructed to cluster most of the known spidroins in gene clades. This is the first large-scale, multi-organism transcriptome for spider spinning glands and a first step into a broad understanding of spider web systems biology and evolution.

  12. Salivary Gland Secretion.

    Science.gov (United States)

    Dorman, H. L.; And Others

    1981-01-01

    Describes materials and procedures for an experiment utilizing a live dog to demonstrate: (1) physiology of the salivary gland; (2) parasympathetic control of the salivary gland; (3) influence of varying salivary flow rates on sodium and potassium ions, osmolarity and pH; and (4) salivary secretion as an active process. (DS)

  13. Salivary Gland Cancer

    Science.gov (United States)

    ... contains antibodies that can kill germs. Salivary gland cancer is a type of head and neck cancer. It is rare. It may not cause any ... pain in your face Doctors diagnose salivary gland cancer using a physical exam, imaging tests, and a ...

  14. Effect of degumming ph value on electrospining of silk fibroin

    Directory of Open Access Journals (Sweden)

    Lu Shen-Zhou

    2014-01-01

    Full Text Available Regenerated silk fibroin fibers show properties dependent on the molecular weight of fibroin. The cocoon-degumming approaches had great impact on the degradation of silk fibroin. The effect of degumming pH value to electrospining of fibroin was studied in this paper. The viscosity and molecular weight of regenerated silk fibroin were studied using rheometer and gel electrophoresis. The results showed that the weaker the alkalinity of degumming reagent, there was the milder the effect on silk fibroin molecular. The fibroin fibers can be prepared by electrospining with low concentration of regenerated silk fibroin solution.

  15. Atomistic model of the spider silk nanostructure

    Science.gov (United States)

    Keten, Sinan; Buehler, Markus J.

    2010-04-01

    Spider silk is an ultrastrong and extensible self-assembling biopolymer that outperforms the mechanical characteristics of many synthetic materials including steel. Here we report atomic-level structures that represent aggregates of MaSp1 proteins from the N. Clavipes silk sequence based on a bottom-up computational approach using replica exchange molecular dynamics. We discover that poly-alanine regions predominantly form distinct and orderly beta-sheet crystal domains while disorderly structures are formed by poly-glycine repeats, resembling 31-helices. These could be the molecular source of the large semicrystalline fraction observed in silks, and also form the basis of the so-called "prestretched" molecular configuration. Our structures are validated against experimental data based on dihedral angle pair calculations presented in Ramachandran plots, alpha-carbon atomic distances, as well as secondary structure content.

  16. Silk industry and carbon footprint mitigation

    Science.gov (United States)

    Giacomin, A. M.; Garcia, J. B., Jr.; Zonatti, W. F.; Silva-Santos, M. C.; Laktim, M. C.; Baruque-Ramos, J.

    2017-10-01

    Currently there is a concern with issues related to sustainability and more conscious consumption habits. The carbon footprint measures the total amount of greenhouse gas (GHG) emissions produced directly and indirectly by human activities and is usually expressed in tonnes of carbon dioxide (CO2) equivalents. The present study takes into account data collected in scientific literature regarding the carbon footprint, garments produced with silk fiber and the role of mulberry as a CO2 mitigation tool. There is an indication of a positive correlation between silk garments and carbon footprint mitigation when computed the cultivation of mulberry trees in this calculation. A field of them mitigates CO2 equivalents in a proportion of 735 times the weight of the produced silk fiber by the mulberry cultivated area. At the same time, additional researches are needed in order to identify and evaluate methods to advertise this positive correlation in order to contribute to a more sustainable fashion industry.

  17. Silk fibroin in tissue engineering.

    Science.gov (United States)

    Kasoju, Naresh; Bora, Utpal

    2012-07-01

    Tissue engineering (TE) is a multidisciplinary field that aims at the in vitro engineering of tissues and organs by integrating science and technology of cells, materials and biochemical factors. Mimicking the natural extracellular matrix is one of the critical and challenging technological barriers, for which scaffold engineering has become a prime focus of research within the field of TE. Amongst the variety of materials tested, silk fibroin (SF) is increasingly being recognized as a promising material for scaffold fabrication. Ease of processing, excellent biocompatibility, remarkable mechanical properties and tailorable degradability of SF has been explored for fabrication of various articles such as films, porous matrices, hydrogels, nonwoven mats, etc., and has been investigated for use in various TE applications, including bone, tendon, ligament, cartilage, skin, liver, trachea, nerve, cornea, eardrum, dental, bladder, etc. The current review extensively covers the progress made in the SF-based in vitro engineering and regeneration of various human tissues and identifies opportunities for further development of this field. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Multifunctional silk-heparin biomaterials for vascular tissue engineering applications

    Science.gov (United States)

    Seib, F. Philipp; Herklotz, Manuela; Burke, Kelly A.; Maitz, Manfred F.; Werner, Carsten; Kaplan, David L.

    2013-01-01

    Over the past 30 years, silk has been proposed for numerous biomedical applications that go beyond its traditional use as a suture material. Silk sutures are well tolerated in humans, but the use of silk for vascular engineering applications still requires extensive biocompatibility testing. Some studies have indicated a need to modify silk to yield a hemocompatible surface. This study examined the potential of low molecular weight heparin as a material for refining silk properties by acting as a carrier for vascular endothelial growth factor (VEGF) and improving silk hemocompatibility. Heparinized silk showed a controlled VEGF release over 6 days; the released VEGF was bioactive and supported the growth of human endothelial cells. Silk samples were then assessed using a humanized hemocompatibility system that employs whole blood and endothelial cells. The overall thrombogenic response for silk was very low and similar to the clinical reference material polytetrafluoroethylene. Despite an initial inflammatory response to silk, apparent as complement and leukocyte activation, the endothelium was maintained in a resting, anticoagulant state. The low thrombogenic response and the ability to control VEGF release support the further development of silk for vascular applications. PMID:24099708

  19. Alimentary Canal of the Adult Blow Fly, Chrysomya megacephala (F. (Diptera: Calliphoridae—Part I: Ultrastructure of Salivary Glands

    Directory of Open Access Journals (Sweden)

    Worachote Boonsriwong

    2012-01-01

    Full Text Available The salivary gland ultrastructure of the adult male blow fly, Chrysomya megacephala (F. (Diptera: Calliphoridae, was investigated at the ultrastructural level using light microscopy (LM, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. The salivary glands are paired structures composed of a single median deferent duct bifurcated into two long, narrow efferent ducts connected to the coiled tubular glands. The SEM image of the gland surface revealed that the basal lamina is relatively smooth in general, but the whole surface appeared as a trace of rough swollen insertion by intense tracheal ramification. Ultrastructurally, the salivary gland is enclosed within the basal lamina, and interdigitation cytoplasmic extensions were apparent between the adjacent gland cells. The basement membrane appeared infoldings that is similar to the complex of the labyrinth channel. The cytoplasm characteristic of the gland revealed high activity, based on the abundance of noticeable secretory granules, either singly or in an aggregated reservoir. In addition, mitochondria were found to intersperse among rich parallel of arrays rough endoplasmic reticulum. Thick cuticle, which was well-delineated and electron dense, apically lined the gland compartments, with discontinuity of the double-layer cuticle revealing a trace of secretion discharged into the lumen. Gross anatomy of the adult salivary gland was markedly different from that of the third instar of the same species, and structural dissimilarity is discussed briefly.

  20. Variation in Protein Intake Induces Variation in Spider Silk Expression

    Science.gov (United States)

    Blamires, Sean J.; Wu, Chun-Lin; Tso, I-Min

    2012-01-01

    Background It is energetically expensive to synthesize certain amino acids. The proteins (spidroins) of spider major ampullate (MA) silk, MaSp1 and MaSp2, differ in amino acid composition. Glutamine and proline are prevalent in MaSp2 and are expensive to synthesize. Since most orb web spiders express high proline silk they might preferentially attain the amino acids needed for silk from food and shift toward expressing more MaSp1 in their MA silk when starved. Methodology/Principal Findings We fed three spiders; Argiope aetherea, Cyrtophora moluccensis and Leucauge blanda, high protein, low protein or no protein solutions. A. aetherea and L. blanda MA silks are high in proline, while C. moluccesnsis MA silks are low in proline. After 10 days of feeding we determined the amino acid compositions and mechanical properties of each species' MA silk and compared them between species and treatments with pre-treatment samples, accounting for ancestry. We found that the proline and glutamine of A. aetherea and L. blanda silks were affected by protein intake; significantly decreasing under the low and no protein intake treatments. Glutmaine composition in C. moluccensis silk was likewise affected by protein intake. However, the composition of proline in their MA silk was not significantly affected by protein intake. Conclusions Our results suggest that protein limitation induces a shift toward different silk proteins with lower glutamine and/or proline content. Contradictions to the MaSp model lie in the findings that C. moluccensis MA silks did not experience a significant reduction in proline and A. aetherea did not experience a significant reduction in serine on low/no protein. The mechanical properties of the silks could not be explained by a MaSp1 expressional shift. Factors other than MaSp expression, such as the expression of spidroin-like orthologues, may impact on silk amino acid composition and spinning and glandular processes may impact mechanics. PMID:22363691

  1. Instar- and stage-specific photoperiodic diapause response of Lygus hesperus (Hemiptera: Miridae)

    Science.gov (United States)

    The western tarnished plant bug (Lygus hesperus Knight)(Hemiptera:Miridae) is a polyphagous pest of numerous western crops. This pest overwinters in a relatively short duration adult diapause, but many details regarding diapause induction and maintenance remain unstudied. Instar-specific responses t...

  2. The coffee berry borer, Hypothenemus hampei: how many instars are there?

    Science.gov (United States)

    After more than a century since the description of the coffee berry borer, Hypothenemus hampei (Ferrari), and dozens of scientific articles on the basic biology of the insect, there is still debate on the number of female larval instars. This paper analyzes the metamorphosis of H. hampei females thr...

  3. Ingestion of a marked bacterial pathogen of cotton conclusively demonstrates feeding by first instar southern green stink bug (Hemiptera: Pentatomidae)

    Science.gov (United States)

    Long-held dogma dictates that 1st instars of Nezara viridula (L.) do not feed, yet recent observations of stylet activity within a food source suggest otherwise. As a cosmopolitan pest of cotton and other high-value cash crops, confirmation of feeding by 1st instars may ultimately influence the biol...

  4. Developmental plasticity in Tenebrio molitor (Coleoptera: Tenebrionidae): Analysis of Instar Variation in Number and Development Time under Different Diets

    Science.gov (United States)

    The variation in instar number and the pattern of sequential instar development time of Tenebrio molitor L. (Coleoptera: Tenebrionidae) was studied under 4 different diet regimes. Addition of dietary supplements consisting of dry potato or a mix of dry potato and dry egg whites significantly reduced...

  5. 21 CFR 184.1262 - Corn silk and corn silk extract.

    Science.gov (United States)

    2010-04-01

    ... specific limitations: Category of food Maximum level of use in food (as served) 1 Functional use Baked... chapter 10 Do. Soft candy, § 170.3(n)(38) of this chapter 20 Do. All other food categories 4 Do. 1 Parts... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Corn silk and corn silk extract. 184.1262 Section...

  6. [The pathology of salivary glands. Tumors of the salivary glands].

    Science.gov (United States)

    Mahy, P; Reychler, H

    2006-01-01

    The management of benign and malignant neoplasms of the salivary glands requires precise knowledge of tumor histogenesis and classification as well as surgical skills. Pleomorphic adenoma and Whartin's tumor are the most frequent tumors in parotid glands while the probability for malignant tumors is higher in other glands, especially in sublingual and minor salivary glands. Those malignant salivary glands tumors are rare and necessitate multidisciplinar staging and management in close collaboration with the pathologist and the radiation oncologist.

  7. Adrenal Gland Disorders

    Science.gov (United States)

    ... Cushing's syndrome, there's too much cortisol, while with Addison's disease, there is too little. Some people are born unable to make enough cortisol. Causes of adrenal gland disorders include Genetic mutations Tumors ...

  8. Mammary gland stem cells

    DEFF Research Database (Denmark)

    Fridriksdottir, Agla J R; Petersen, Ole W; Rønnov-Jessen, Lone

    2011-01-01

    Distinct subsets of cells, including cells with stem cell-like properties, have been proposed to exist in normal human breast epithelium and breast carcinomas. The cellular origins of epithelial cells contributing to gland development, tissue homeostasis and cancer are, however, still poorly...... and differences between mouse and human gland development with particular emphasis on the identity and localization of stem cells, and the influence of the surrounding microenvironment. It is concluded that while recent advances in the field have contributed immense insight into how the normal mammary gland...... develops and is maintained, significant discrepancies exist between the mouse and human gland which should be taken into consideration in current and future models of mammary stem cell biology....

  9. Enzymatically crosslinked silk-hyaluronic acid hydrogels.

    Science.gov (United States)

    Raia, Nicole R; Partlow, Benjamin P; McGill, Meghan; Kimmerling, Erica Palma; Ghezzi, Chiara E; Kaplan, David L

    2017-07-01

    In this study, silk fibroin and hyaluronic acid (HA) were enzymatically crosslinked to form biocompatible composite hydrogels with tunable mechanical properties similar to that of native tissues. The formation of di-tyrosine crosslinks between silk fibroin proteins via horseradish peroxidase has resulted in a highly elastic hydrogel but exhibits time-dependent stiffening related to silk self-assembly and crystallization. Utilizing the same method of crosslinking, tyramine-substituted HA forms hydrophilic and bioactive hydrogels that tend to have limited mechanics and degrade rapidly. To address the limitations of these singular component scaffolds, HA was covalently crosslinked with silk, forming a composite hydrogel that exhibited both mechanical integrity and hydrophilicity. The composite hydrogels were assessed using unconfined compression and infrared spectroscopy to reveal of the physical properties over time in relation to polymer concentration. In addition, the hydrogels were characterized by enzymatic degradation and for cytotoxicity. Results showed that increasing HA concentration, decreased gelation time, increased degradation rate, and reduced changes that were observed over time in mechanics, water retention, and crystallization. These hydrogel composites provide a biologically relevant system with controllable temporal stiffening and elasticity, thus offering enhanced tunable scaffolds for short or long term applications in tissue engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Mud and silk in the dark

    DEFF Research Database (Denmark)

    P. S. Reboleira, Ana Sofia; Enghoff, Henrik

    2016-01-01

    chamber, using the available substrate reinforced by a silken web. We present the detailed ultrastructure of the moulting chamber and silk. It takes five days to build the moulting chamber and between 29 (female) and 35 (male) days to shed the exuviae. The male maturation moult is preceded...

  11. Solubilization of silk protein by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sudatis, Boonya; Pongpat, Suchada [Office of Atomic Energy of Peace, Bangkok (Thailand)

    2002-03-01

    Gamma irradiated silk fibroin at doses of 0, 5, 10, 20, 40, 60, 80, 100, 125, 250, 500, 750 and 1000 kGy were soaked in water for 1 hr. Silk fibroin solubilized percentage was investigated from lost weight of sample (dried at 105{sup 0}C), they were 0, 0, 0.7, 0, 0.11, 0.11, 0, 0.73, 0.77, 4.38, 8.32, 10.22 and 18.52 respectively. It showed that at the higher dose up to 250 kGy had direct effect to solubility, and increased with increasing dose. In addition, silk sericin dissolved 77.76, 82.22, 83.55, 84.31, 86.04, 86.67 and 87.37% after gamma irradiation at the doses of 0, 50, 100, 200, 500, 750 and 1000 kGy respectively. It presents that radiation can cause silk protein, fibroin and sericin dissolve because of their degradation. (author)

  12. Curcumin-functionalized silk biomaterials for anti-aging utility.

    Science.gov (United States)

    Yang, Lei; Zheng, Zhaozhu; Qian, Cheng; Wu, Jianbing; Liu, Yawen; Guo, Shaozhe; Li, Gang; Liu, Meng; Wang, Xiaoqin; Kaplan, David L

    2017-06-15

    Curcumin is a natural antioxidant that is isolated from turmeric (Curcuma longa) and exhibits strong free radical scavenging activity, thus functional for anti-aging. However, poor stability and low solubility of curcumin in aqueous conditions limit its biomedical applications. Previous studies have shown that the anti-oxidation activity of curcumin embedded in silk fibroin films could be well preserved, resulting in the promoted adipogenesis from human mesenchymal stem cells (hMSCs) cultured on the surface of the films. In the present study, curcumin was encapsulated in both silk fibroin films (silk/cur films) and nanoparticles (silk/cur NPs), and their anti-aging effects were compared with free curcumin in solution, with an aim to elucidate the mechanism of anti-aging of silk-associated curcumin and to better serve biomedical applications in the future. The morphology and structure of silk/cur film and silk/cur NP were characterized using SEM, FTIR and DSC, indicating characteristic stable beta-sheet structure formation in the materials. Strong binding of curcumin molecules to the beta-sheet domains of silk fibroin resulted in the slow release of curcumin with well-preserved activity from the materials. For cell aging studies, rat bone marrow mesenchymal stem cells (rBMSCs) were cultured in the presence of free curcumin (FC), silk/cur film and silk/cur NP, and cell proliferation and markers of aging (P53, P16, HSP70 gene expression and β-Galactosidase activity) were examined. The results indicated that cell aging was retarded in all FC, silk/cur NP and silk/cur film samples, with the silk-associated curcumin superior to the FC. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Radionuclide salivary gland imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mishkin, F.S.

    1981-10-01

    Salivary gland imaging with 99mTc as pertechnetate provides functional information concerning trapping and excretion of the parotid and submandibular glands. Anatomic information gained often adds little to clinical evaluation. On the other hand, functional information may detect subclinical involvement, which correlates well with biopsy of the minor labial salivary glands. Salivary gland abnormalities in systemic disease such as sarcoidosis, rheumatoid arthritis, lupus erythematosus, and other collagenvascular disorders may be detected before they result in the clinical manifestaions of Sjoegren's syndrome. Such glands, after initially demonstrating increased trapping in the acute phase, tend to have decreased trapping and failure to discharge pertechnetate in response to an appropriate physiologic stimulus. Increased uptake of gallium-67 citrate often accompanies these findings. Inflammatory parotitis can be suspected when increased perfusion is evident on radionuclide angiography with any agent. The ability of the salivary gland image to detect and categorize mass lesions, which result in focal areas of diminished activity such as tumors, cysts, and most other masses, is disappointing, while its ability to detect and categorize Warthin's tumor, which concentrates pertechnetate, is much more valuable, although not specific.

  14. Radionuclide salivary gland imaging

    International Nuclear Information System (INIS)

    Mishkin, F.S.

    1981-01-01

    Salivary gland imaging with 99mTc as pertechnetate provides functional information concerning trapping and excretion of the parotid and submandibular glands. Anatomic information gained often adds little to clinical evaluation. On the other hand, functional information may detect subclinical involvement, which correlates well with biopsy of the minor labial salivary glands. Salivary gland abnormalities in systemic disease such as sarcoidosis, rheumatoid arthritis, lupus erythematosus, and other collagenvascular disorders may be detected before they result in the clinical manifestaions of Sjoegren's syndrome. Such glands, after initially demonstrating increased trapping in the acute phase, tend to have decreased trapping and failure to discharge pertechnetate in response to an appropriate physiologic stimulus. Increased uptake of gallium-67 citrate often accompanies these findings. Inflammatory parotitis can be suspected when increased perfusion is evident on radionuclide angiography with any agent. The ability of the salivary gland image to detect and categorize mass lesions, which result in focal areas of diminished activity such as tumors, cysts, and most other masses, is disappointing, while its ability to detect and categorize Warthin's tumor, which concentrates pertechnetate, is much more valuable, although not specific

  15. 3D freeform printing of silk fibroin.

    Science.gov (United States)

    Rodriguez, Maria J; Dixon, Thomas A; Cohen, Eliad; Huang, Wenwen; Omenetto, Fiorenzo G; Kaplan, David L

    2018-04-15

    Freeform fabrication has emerged as a key direction in printing biologically-relevant materials and structures. With this emerging technology, complex structures with microscale resolution can be created in arbitrary geometries and without the limitations found in traditional bottom-up or top-down additive manufacturing methods. Recent advances in freeform printing have used the physical properties of microparticle-based granular gels as a medium for the submerged extrusion of bioinks. However, most of these techniques require post-processing or crosslinking for the removal of the printed structures (Miller et al., 2015; Jin et al., 2016) [1,2]. In this communication, we introduce a novel method for the one-step gelation of silk fibroin within a suspension of synthetic nanoclay (Laponite) and polyethylene glycol (PEG). Silk fibroin has been used as a biopolymer for bioprinting in several contexts, but chemical or enzymatic additives or bulking agents are needed to stabilize 3D structures. Our method requires no post-processing of printed structures and allows for in situ physical crosslinking of pure aqueous silk fibroin into arbitrary geometries produced through freeform 3D printing. 3D bioprinting has emerged as a technology that can produce biologically relevant structures in defined geometries with microscale resolution. Techniques for fabrication of free-standing structures by printing into granular gel media has been demonstrated previously, however, these methods require crosslinking agents and post-processing steps on printed structures. Our method utilizes one-step gelation of silk fibroin within a suspension of synthetic nanoclay (Laponite), with no need for additional crosslinking compounds or post processing of the material. This new method allows for in situ physical crosslinking of pure aqueous silk fibroin into defined geometries produced through freeform 3D printing. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights

  16. Cytocompatibility of a silk fibroin tubular scaffold

    International Nuclear Information System (INIS)

    Wang, Jiannan; Wei, Yali; Yi, Honggen; Liu, Zhiwu; Sun, Dan; Zhao, Huanrong

    2014-01-01

    Regenerated silk fibroin (SF) materials are increasingly used for tissue engineering applications. In order to explore the feasibility of a novel biomimetic silk fibroin tubular scaffold (SFTS) crosslinked by poly(ethylene glycol) diglycidyl ether (PEG-DE), biocompatibility with cells was evaluated. The novel biomimetic design of the SFTS consisted of three distinct layers: a regenerated SF intima, a silk braided media and a regenerated SF adventitia. The SFTS exhibited even silk fibroin penetration throughout the braid, forming a porous layered tube with superior mechanical, permeable and cell adhesion properties that are beneficial to vascular regeneration. Cytotoxicity and cell compatibility were tested on L929 cells and human umbilical vein endothelial cells (EA.hy926). DNA content analysis, scanning electron and confocal microscopies and MTT assay showed no inhibitory effects on DNA replication. Cell morphology, viability and proliferation were good for L929 cells, and satisfactory for EA.hy926 cells. Furthermore, the suture retention strength of the SFTS was about 23 N and the Young's modulus was 0.2–0.3 MPa. Collectively, these data demonstrate that PEG-DE crosslinked SFTS possesses the appropriate cytocompatibility and mechanical properties for use as vascular scaffolds as an alternative to vascular autografts. - Highlights: • A PEG-DE cross-linked small caliber porous silk fibroin tubular scaffold (SFTS) • PEG-DE cross-linked SF film had no inhibitory effect on DNA replication of cells. • Cells cultured on the SFTS showed good morphology, cell viability and proliferative activity. • SFTS would be beneficial to endothelialization. • SFTS had good suture retention strength and flexibility

  17. Electrodeposited silk coatings for functionalized implant applications

    Science.gov (United States)

    Elia, Roberto

    The mechanical and morphological properties of titanium as well as its biocompatibility and osteoinductive characteristics have made it the material of choice for dental implant systems. Although the success rate of titanium implants exceeds 90% in healthy individuals, a large subset of the population has one or more risk factors that inhibit implant integration. Treatments and coatings have been developed to improve clinical outcomes via introduction of appropriate surface topography, texture and roughness or incorporation of bioactive molecules. It is essential that the coatings and associated deposition techniques are controllable and reproducible. Currently, methods of depositing functional coatings are dictated by numerous parameters (temperature, particle size distribution, pH and voltage), which result in variable coating thickness, strength, porosity and weight, and hinder or preclude biomolecule incorporation. Silk is a highly versatile protein with a unique combination of mechanical and physical properties, including tunable degradation, biocompatibility, drug stabilizing capabilities and mechanical properties. Most recently an electrogelation technique was developed which allows for the deposition of gels which dry seamlessly over the contoured topography of the conductive substrate. In this work we examine the potential use of silk electrogels as mechanically robust implant coatings capable of sequestering and releasing therapeutic agents. Electrodeposition of silk electrogels formed in uniform electric fields was characterized with respect to field intensity and deposition time. Gel formation kinetics were used to derive functions which allowed for the prediction of coating deposition over a range of process and solution parameters. Silk electrogel growth orientation was shown to be influenced by the applied electric field. Coatings were reproducible and tunable via intrinsic silk solution properties and extrinsic process parameters. Adhesion was

  18. Spider Silk Processing for Spidroin Recovery from Crossopriza Lyoni Web

    Science.gov (United States)

    Mohtar, J. A.; Ooi, W. L.; Yusuf, F.

    2018-03-01

    Spider silk is a potential biomaterial that can be used in various applications for its outstanding physicomechanical properties attributed by the spidroin composition. Efforts for commercializing spider silks have been mainly focused on the characterization of spidroins from the Entelegyne spiders for exceptional fibre construction. Hence, studies on silk proteins from the Haplogyne species remain neglected. The aim of this study is to isolate spidroin from Crossopriza lyoni web. Silk processing involved the pretreatment of fibres for the shell layer removal from the surface. A screening study was conducted to analyze the effect of temperature, incubation time and agitation speed on spidroin extraction using Ajisawa’s reagent by OFAT analysis followed by statistical optimization of the extraction process via RSM for maximal protein recovery. All parameters exerted significant effect on spidroin recovery (pspider silk to meet the demand for a variety of silk-based products in the near future.

  19. Thin Film Assembly of Spider Silk-like Block Copolymers

    Science.gov (United States)

    2011-01-01

    Shipley, N. H.; Lewis, R. V. Int. J. Biol.Macromol. 1999, 24, 271. (c) Thiel, B. L.; Guess, K. B.; Viney, C. Biopolymers 1997, 41, 703. (13) Silk ...Film Assembly of Spider Silk -like Block Copolymers Sreevidhya T. Krishnaji,†,‡ Wenwen Huang,§ Olena Rabotyagova,†,‡ Eugenia Kharlampieva, ) Ikjun Choi...Received November 26, 2010 We report the self-assembly of monolayers of spider silk -like block copolymers. Langmuir isotherms were obtained for a series of

  20. The effects of corn silk on glycaemic metabolism

    OpenAIRE

    Han Linna; Liu Tongjun; Guo Jianyou; Liu Yongmei

    2009-01-01

    Abstract Background Corn silk contains proteins, vitamins, carbohydrates, Ca, K, Mg and Na salts, fixed and volatile oils, steroids such as sitosterol and stigmasterol, alkaloids, saponins, tannins, and flavonoids. Base on folk remedies, corn silk has been used as an oral antidiabetic agent in China for decades. However, the hypoglycemic activity of it has not yet been understood in terms of modern pharmacological concepts. The purpose of this study is to investigate the effects of corn silk ...

  1. Ptychographic X-ray Tomography of Silk Fiber Hydration

    DEFF Research Database (Denmark)

    Esmaeili, Morteza; Fløystad, Jostein B.; Diaz, Ana

    2013-01-01

    Studying noninvasively the internal nanoporous structure of a single Tussah silk fiber under different humidity conditions, we demonstrate for the first time the feasibility of in-situ ptychographic tomography. The resulting 3D images of the silk fiber interior, obtained at both dry and humid con...... normal to the fiber axis. Exploiting quantitative information on the fiber’s electron density, hydration was found to proceed through interaction with the silk protein rather than filling of pores....

  2. Mechanism of Stabilization of Labile Compounds by Silk Fibroin Proteins

    Science.gov (United States)

    2017-04-05

    saliva, or urine , and their collection and storage is critical to obtain reliable results. Without proper temperature regulation protein biomarkers in... samples for long-term ambient storage and subsequent on-demand recovery and laboratory analysis. Air dried silks provide a protective barrier that...silk in the stabilization of a range of different analytes, including entrapment, storage and recovery. Here, we successfully used silk fibroin as a

  3. SilkDB: a knowledgebase for silkworm biology and genomics

    DEFF Research Database (Denmark)

    Wang, Jing; Xia, Qingyou; He, Ximiao

    2005-01-01

    The Silkworm Knowledgebase (SilkDB) is a web-based repository for the curation, integration and study of silkworm genetic and genomic data. With the recent accomplishment of a approximately 6X draft genome sequence of the domestic silkworm (Bombyx mori), SilkDB provides an integrated representati....... SilkDB is publicly accessible at http://silkworm.genomics.org.cn. Udgivelsesdato: 2005-Jan-1...

  4. Metal nanoparticles triggered persistent negative photoconductivity in silk protein hydrogels

    Science.gov (United States)

    Gogurla, Narendar; Sinha, Arun K.; Naskar, Deboki; Kundu, Subhas C.; Ray, Samit K.

    2016-03-01

    Silk protein is a natural biopolymer with intriguing properties, which are attractive for next generation bio-integrated electronic and photonic devices. Here, we demonstrate the negative photoconductive response of Bombyx mori silk protein fibroin hydrogels, triggered by Au nanoparticles. The room temperature electrical conductivity of Au-silk hydrogels is found to be enhanced with the incorporation of Au nanoparticles over the control sample, due to the increased charge transporting networks within the hydrogel. Au-silk lateral photoconductor devices show a unique negative photoconductive response under an illumination of 325 nm, with excitation energy higher than the characteristic metal plasmon resonance band. The enhanced photoconductance yield in the hydrogels over the silk protein is attributed to the photo-oxidation of amino groups in the β-pleated sheets of the silk around the Au nanoparticles followed by the breaking of charge transport networks. The Au-silk nanocomposite does not show any photoresponse under visible illumination because of the localization of excited charges in Au nanoparticles. The negative photoconductive response of hybrid Au-silk under UV illumination may pave the way towards the utilization of silk for future bio-photonic devices using metal nanoparticle platforms.

  5. Structure-function-property-design interplay in biopolymers: spider silk.

    Science.gov (United States)

    Tokareva, Olena; Jacobsen, Matthew; Buehler, Markus; Wong, Joyce; Kaplan, David L

    2014-04-01

    Spider silks have been a focus of research for almost two decades due to their outstanding mechanical and biophysical properties. Recent advances in genetic engineering have led to the synthesis of recombinant spider silks, thus helping to unravel a fundamental understanding of structure-function-property relationships. The relationships between molecular composition, secondary structures and mechanical properties found in different types of spider silks are described, along with a discussion of artificial spinning of these proteins and their bioapplications, including the role of silks in biomineralization and fabrication of biomaterials with controlled properties. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  6. Fabrication and Biocompatibility of Electrospun Silk Biocomposites

    Directory of Open Access Journals (Sweden)

    Ick-Soo Kim

    2011-10-01

    Full Text Available Silk fibroin has attracted great interest in tissue engineering because of its outstanding biocompatibility, biodegradability and minimal inflammatory reaction. In this study, two kinds of biocomposites based on regenerated silk fibroin are fabricated by electrospinning and post-treatment processes, respectively. Firstly, regenerated silk fibroin/tetramethoxysilane (TMOS hybrid nanofibers with high hydrophilicity are prepared, which is superior for fibroblast attachment. The electrospinning process causes adjacent fibers to ‘weld’ at contact points, which can be proved by scanning electron microscope (SEM. The water contact angle of silk/tetramethoxysilane (TMOS composites shows a sharper decrease than pure regenerated silk fibroin nanofiber, which has a great effect on the early stage of cell attachment behavior. Secondly, a novel tissue engineering scaffold material based on electrospun silk fibroin/nano-hydroxyapatite (nHA biocomposites is prepared by means of an effective calcium and phosphate (Ca–P alternate soaking method. nHA is successfully produced on regenerated silk fibroin nanofiber within several min without any pre-treatments. The osteoblastic activities of this novel nanofibrous biocomposites are also investigated by employing osteoblastic-like MC3T3-E1 cell line. The cell functionality such as alkaline phosphatase (ALP activity is ameliorated on mineralized silk nanofibers. All these results indicate that this silk/nHA biocomposite scaffold material may be a promising biomaterial for bone tissue engineering.

  7. Spider Silk as Guiding Biomaterial for Human Model Neurons

    Directory of Open Access Journals (Sweden)

    Frank Roloff

    2014-01-01

    Full Text Available Over the last years, a number of therapeutic strategies have emerged to promote axonal regeneration. An attractive strategy is the implantation of biodegradable and nonimmunogenic artificial scaffolds into injured peripheral nerves. In previous studies, transplantation of decellularized veins filled with spider silk for bridging critical size nerve defects resulted in axonal regeneration and remyelination by invading endogenous Schwann cells. Detailed interaction of elongating neurons and the spider silk as guidance material is unknown. To visualize direct cellular interactions between spider silk and neurons in vitro, we developed an in vitro crossed silk fiber array. Here, we describe in detail for the first time that human (NT2 model neurons attach to silk scaffolds. Extending neurites can bridge gaps between single silk fibers and elongate afterwards on the neighboring fiber. Culturing human neurons on the silk arrays led to an increasing migration and adhesion of neuronal cell bodies to the spider silk fibers. Within three to four weeks, clustered somata and extending neurites formed ganglion-like cell structures. Microscopic imaging of human neurons on the crossed fiber arrays in vitro will allow for a more efficient development of methods to maximize cell adhesion and neurite growth on spider silk prior to transplantation studies.

  8. Second-order nonlinear optical microscopy of spider silk

    Science.gov (United States)

    Zhao, Yue; Hien, Khuat Thi Thu; Mizutani, Goro; Rutt, Harvey N.

    2017-06-01

    Asymmetric β-sheet protein structures in spider silk should induce nonlinear optical interaction such as second harmonic generation (SHG) which is experimentally observed for a radial line and dragline spider silk using an imaging femtosecond laser SHG microscope. By comparing different spider silks, we found that the SHG signal correlates with the existence of the protein β-sheets. Measurements of the polarization dependence of SHG from the dragline indicated that the β-sheet has a nonlinear response depending on the direction of the incident electric field. We propose a model of what orientation the β-sheet takes in spider silk.

  9. Instar- and host-associated differentiation of bacterial communities in the Mediterranean fruit fly Ceratitis capitata

    OpenAIRE

    Malacrinò, Antonino; Campolo, Orlando; Medina, Raul F; Palmeri, Vincenzo

    2018-01-01

    Microorganisms are acknowledged for their role in shaping insects' evolution, life history and ecology. Previous studies have shown that microbial communities harbored within insects vary through ontogenetic development and among insects feeding on different host-plant species. In this study, we characterized the bacterial microbiota of the highly polyphagous Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), at different instars and when feeding on different host-plant speci...

  10. The Effects of Biopesticide Azadirachtin on the Fifth Instar Galleria mellonella L. (Lepidoptera: Pyralidae) Larval Integument

    OpenAIRE

    Ünsal, Sadettin; Güner, Emine

    2016-01-01

    The chitin synthesis inhibitory (CSI) effects of azadirachtin on the fifth instar Galleria mellonella L. larval integument were investigated. Using probit analysis, the LC95 value for G. mellonella larvae was detected as 3991 ppm. In this study, 3991 ppm and the reduced 1995, 997, and 498 ppm concentrations were used. It was observed that azadirachtin had different effects on the integument when the larvae were fed semi-synthetic feed containing 498, 997, 1995, or 3991 ppm azadirachtin. Morph...

  11. Last instar larva of Microstigmus nigrophthalmus Melo (Hymenoptera, Crabronidae, Pemphredoninae, with notes on biology

    Directory of Open Access Journals (Sweden)

    Sandor Christiano Buys

    2002-09-01

    Full Text Available The last instar larva of Microstigmus nigrophthalmus Melo, 1992 is described. It markedly differs from that of M. comes Krombein, 1967 the only other species in the genus whose mature larva have been described, for features as follows: presence of spinnerets; setae on the labrum, maxillae and labium; mandibles with tridentate apex and a bidentate lateral projection; lack of the conical supranal processo Notes on habitat, structure, and content of nests are also presented.

  12. Observations of the third instar larva and puparium of Chrysomya bezziana (Diptera: Calliphoridae).

    Science.gov (United States)

    Sukontason, K L; Piangjai, S; Boonsriwong, W; Bunchu, N; Ngern-klun, R; Vogtsberger, R C; Sukontason, K

    2006-11-01

    Observations on the ultrastructure of the third instar larva and puparium of the Old World screw-worm fly, Chrysomya bezziana, are presented utilizing both light microscopy (LM) and scanning electron microscopy (SEM). Results of this study indicate that the shape of the intersegmental spines between the pro- and mesothorax markedly differ from other blow fly species (Chrysomya megacephala, Chrysomya rufifacies, Chrysomya nigripes, Lucilia cuprina) in being broad-based with sharp recurved tips. Other characters such as the posterior spiracles, number of papillae on the anterior spiracles, oral grooves, and posterior spiracular hairs also differ. The strong and robust mouthhooks may explain the ability of larvae to penetrate deeply into human tissues. Perforated sieve plates covered with antler-like projections were observed within the anterior spiracles of the puparium of C. bezziana. The posterior spiracular discs each bear three spiracular slits with approximately 2-microm wide openings that were viewed either open or closed by a membrane underneath. This study expands our knowledge of the fine details of the external morphology of both the third instar larva and puparium of C. bezziana, which is an obligatory myiasis-producing species in many regions. A key to differentiate the third instar of C. bezziana from other blow flies in Thailand is given.

  13. Malignant salivary gland tumours

    International Nuclear Information System (INIS)

    Thompson, S.H.

    1982-01-01

    The most frequent malignant salivary gland tumours are the mucoepidermoid tumour, adenoid cystic carcinoma and adenocarcinoma. The major salivary glands and the minor glands of the mouth and upper respiratory tract may potentially develop any of these malignant lesions. Malignant lesions most frequently present as a palpable mass and tend to enlarge more rapidly than benign neoplasms. Pain, paresthesia, muscle paralysis and fixation to surrounding tissue are all ominous signs and symptoms. The only reliable means of differential diagnosis of these lesions is biopsy and histologic analysis. Therapy involves surgery or a combination of surgery and radiation therapy. The ultimate prognosis is governed by the intrinsic biologic behaviour of the neoplasms, the extent of disease and adequate clinical therapy

  14. Malignant salivary gland tumours

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, S.H. (University of the Witwatersrand, Johannesburg (South Africa). Dept. of Oral Pathology)

    1982-08-01

    The most frequent malignant salivary gland tumours are the mucoepidermoid tumour, adenoid cystic carcinoma and adenocarcinoma. The major salivary glands and the minor glands of the mouth and upper respiratory tract may potentially develop any of these malignant lesions. Malignant lesions most frequently present as a palpable mass and tend to enlarge more rapidly than benign neoplasms. Pain, paresthesia, muscle paralysis and fixation to surrounding tissue are all ominous signs and symptoms. The only reliable means of differential diagnosis of these lesions is biopsy and histologic analysis. Therapy involves surgery or a combination of surgery and radiation therapy. The ultimate prognosis is governed by the intrinsic biologic behaviour of the neoplasms, the extent of disease and adequate clinical therapy.

  15. Lacrimal gland ductal carcinomas

    DEFF Research Database (Denmark)

    Andreasen, Simon; Grauslund, Morten; Heegaard, Steffen

    2017-01-01

    and xerophtalmia; case 2: A 53-year-old man, presented with headache, proptosis and chemosis and case 3: A 73-year-old man, presenting with chemosis and a corneal abscess. All three cases were characterized morphologically including immunohistochemistry and genetically with fluorescence in situ hybridization (FISH...... HER2 amplification was found in cases 2 and 3. CONCLUSION: This study identified a spectrum of genetic events and pattern of protein expression in DC of the lacrimal gland similar to a subset of carcinomas of the breast and ductal carcinomas of the salivary glands. For therapeutic purposes...

  16. Silk constructs for delivery of muskuloskeletal therapeutics

    Science.gov (United States)

    Meinel, Lorenz; Kaplan, David L.

    2012-01-01

    Silk fibroin (SF) is a biopolymer with distinguishing features from many other bio- as well as synthetic polymers. From a biomechanical and drug delivery perspective, SF combines remarkable versatility for scaffolding (solid implants, hydrogels, threads, solutions), with advanced mechanical properties and good stabilization and controlled delivery of entrapped protein and small molecule drugs, respectively. It is this combination of mechanical and pharmaceutical features which render SF so exciting for biomedical applications. his pattern along with the versatility of this biopolymer have been translated into progress for musculoskeletal applications. We review the use and potential of silk fibroin for systemic and localized delivery of therapeutics in diseases affecting the musculoskeletal system. We also present future directions for this biopolymer as well as the necessary research and development steps for their achievement. PMID:22522139

  17. From Nano to Micro: Importance of Structure and Architecture in Spider Silk Adhesives

    Science.gov (United States)

    Sahni, Vasav; Dhinojwala, Ali

    2012-02-01

    Spiders have developed outstanding adhesives over millions of years of evolution for prey capture and locomotion. We show that the structure and architecture of these adhesives play an important role in the adhesion. The adhesive produced by orb-weaving spiders to capture prey (viscid glue) is laid on a pair of silk fibers as micron-size glue drops composed of salts and glycoproteins. By stretching single drops, we show that viscid glue behaves like a viscoelastic solid and that elasticity is critical in enhancing adhesion caused by specific adhesive ligands by over 100 times. Comparing viscid glue with gumfoot glue, the glue produced by cob-weavers, the evolutionary descendants of orb-weavers, showed that, in spite of being produced in homologous aggregate glands, gumfoot glue behaves like a viscoelastic liquid. Moreover, gumfoot glue is humidity-resistant and viscid glue is humidity-sensitive. We use a synthetic strategy to spin beads-on-a-string (BOAS) architecture to mimic the adhesive properties of spider silk. Using these mimic threads, we show that the BOAS structure adheres more than a cylindrical structure during contact (collision of prey) and during separation (escape attempt of prey). These results inspire design of novel tunable adhesives.

  18. Silk fibroin nanostructured materials for biomedical applications

    Science.gov (United States)

    Mitropoulos, Alexander N.

    Nanostructured biopolymers have proven to be promising to develop novel biomedical applications where forming structures at the nanoscale normally occurs by self-assembly. However, synthesizing these structures can also occur by inducing materials to transition into other forms by adding chemical cross-linkers, changing pH, or changing ionic composition. Understanding the generation of nanostructures in fluid environments, such as liquid organic solvents or supercritical fluids, has not been thoroughly examined, particularly those that are based on protein-based block-copolymers. Here, we examine the transformation of reconstituted silk fibroin, which has emerged as a promising biopolymer due to its biocompatibility, biodegradability, and ease of functionalization, into submicron spheres and gel networks which offer applications in tissue engineering and advanced sensors. Two types of gel networks, hydrogels and aerogels, have small pores and large surface areas that are defined by their structure. We design and analyze silk nanoparticle formation using a microfluidic device while offering an application for drug delivery. Additionally, we provide a model and characterize hydrogel formation from micelles to nanoparticles, while investigating cellular response to the hydrogel in an in vitro cell culture model. Lastly, we provide a second model of nanofiber formation during near-critical and supercritical drying and characterize the silk fibroin properties at different drying pressures which, when acting as a stabilizing matrix, shows to improve the activity of entrapped enzymes dried at different pressures. This work has created new nanostructured silk fibroin forms to benefit biomedical applications that could be applied to other fibrous proteins.

  19. Gaochang Buddhism and the Silk Road

    Directory of Open Access Journals (Sweden)

    Wang Xin

    2014-02-01

    Full Text Available At the crossroads between the West and the East in ancient times, one point along the Silk Road was Gaochang (the Turpan basin in Xinjiang which played an important role in cultural exchange and the spread of Buddhism. The bidirectional influence of Buddhism in Gaochang was achieved as Buddhism spread eastward, and through its westward transmission which resulted in Gaochang’s unique and significant position in the history of cultural interaction.

  20. Interactions between Bacillus thuringiensis and parasitoids of late-instar larvae of the spruce budworm (Lepidoptera: Tortricidae)

    NARCIS (Netherlands)

    Schoenmaker, A.; Cusson, M.; Frankenhuyzen, van K.

    2001-01-01

    We investigated interactions between Bacillus thuringiensis Berliner var. kurstaki and parasitoids that attack late instars of the eastern spruce budworm, Choristoneura fumiferana (Clemens). In a petri-dish arena, females of Tranosema rostrale rostrale (Brishke) (Hymenoptera: Ichneumonidae) were

  1. The effects of corn silk on glycaemic metabolism.

    Science.gov (United States)

    Guo, Jianyou; Liu, Tongjun; Han, Linna; Liu, Yongmei

    2009-11-23

    Corn silk contains proteins, vitamins, carbohydrates, Ca, K, Mg and Na salts, fixed and volatile oils, steroids such as sitosterol and stigmasterol, alkaloids, saponins, tannins, and flavonoids. Base on folk remedies, corn silk has been used as an oral antidiabetic agent in China for decades. However, the hypoglycemic activity of it has not yet been understood in terms of modern pharmacological concepts. The purpose of this study is to investigate the effects of corn silk on glycaemic metabolism. Alloxan and adrenalin induced hyperglycemic mice were used in the study. The effects of corn silk on blood glucose, glycohemoglobin (HbA1c), insulin secretion, damaged pancreatic beta-cells, hepatic glycogen and gluconeogenesis in hyperglycemic mice were studied respectively. After the mice were orally administered with corn silk extract, the blood glucose and the HbA1c were significantly decreased in alloxan-induced hyperglycemic mice (p corn silk extract 15 days later. Also, the body weight of the alloxan-induced hyperglycemic mice was increased gradually. However, ascension of blood glucose induced by adrenalin and gluconeogenesis induced by L-alanine were not inhibited by corn silk extract treatment (p > 0.05). Although corn silk extract increased the level of hepatic glycogen in the alloxan-induced hyperglycemic mice, there was no significant difference between them and that of the control group(p > 0.05). Corn silk extract markedly reduced hyperglycemia in alloxan-induced diabetic mice. The action of corn silk extract on glycaemic metabolism is not via increasing glycogen and inhibiting gluconeogenesis but through increasing insulin level as well as recovering the injured beta-cells. The results suggest that corn silk extract may be used as a hypoglycemic food or medicine for hyperglycemic people in terms of this modern pharmacological study.

  2. Recombinant protein blends: silk beyond natural design.

    Science.gov (United States)

    Dinjaski, Nina; Kaplan, David L

    2016-06-01

    Recombinant DNA technology and new material concepts are shaping future directions in biomaterial science for the design and production of the next-generation biomaterial platforms. Aside from conventionally used synthetic polymers, numerous natural biopolymers (e.g., silk, elastin, collagen, gelatin, alginate, cellulose, keratin, chitin, polyhydroxyalkanoates) have been investigated for properties and manipulation via bioengineering. Genetic engineering provides a path to increase structural and functional complexity of these biopolymers, and thereby expand the catalog of available biomaterials beyond that which exists in nature. In addition, the integration of experimental approaches with computational modeling to analyze sequence-structure-function relationships is starting to have an impact in the field by establishing predictive frameworks for determining material properties. Herein, we review advances in recombinant DNA-mediated protein production and functionalization approaches, with a focus on hybrids or combinations of proteins; recombinant protein blends or 'recombinamers'. We highlight the potential biomedical applications of fibrous protein recombinamers, such as Silk-Elastin Like Polypeptides (SELPs) and Silk-Bacterial Collagens (SBCs). We also discuss the possibility for the rationale design of fibrous proteins to build smart, stimuli-responsive biomaterials for diverse applications. We underline current limitations with production systems for these proteins and discuss the main trends in systems/synthetic biology that may improve recombinant fibrous protein design and production. Copyright © 2016. Published by Elsevier Ltd.

  3. The differential effects of herbivory by first and fourth instars of Trichoplusia ni (Lepidoptera: Noctuidae) on photosynthesis in Arabidopsis thaliana.

    Science.gov (United States)

    Tang, Jennie Y; Zielinski, Raymond E; Zangerl, Arthur R; Crofts, Antony R; Berenbaum, May R; Delucia, Evan H

    2006-01-01

    The effect of different feeding behaviours of 1st and 4th instar Trichoplusia ni on photosynthesis of Arabidopsis thaliana var. Columbia was characterized using spatially resolved measurements of fluorescence and leaf temperature, as well as leaf gas exchange,. First instars made small holes with a large perimeter-to-area ratio and avoided veins, while 4th instars made large holes with a low perimeter-to-area ratio and consumed veins. Herbivory by 1st instars reduced photosynthesis more strongly in the remaining leaf tissue than that by 4th instars. Photosystem II operating efficiency (PhiPSII) was correlated with the rate of CO2 exchange, and reductions in PhiPSII in areas around the missing tissues contributed to a 15.6% reduction in CO2 assimilation on the first day following removal of 1st instars. The corresponding increases in non-photochemical quenching and greater rates of non-stomatal water loss from these regions, as well as the partial reversal of low PhiPSII by increasing the ambient CO2 concentration, suggests that localized water stress and reduced stomatal conductance contributed to the inhibition of photosynthesis. Damage by 1st but not 4th instars reduced the maximum quantum efficiency of photosystem II photochemistry (Fv/Fm) by 4-8%. While herbivory by both 1st and 4th instars increased dark respiration rates, the rates were too low to have contributed to the observed reductions in CO2 exchange. The small holes produced by 1st instars may have isolated patches of tissue from the vascular system thereby contributing to localized water stress. Since neither 1st nor 4th instar herbivory had a detectable effect on the expression of the Rubisco small subunit gene, the observed differences cannot be attributed to changes in expression of this gene. The mode of feeding by different instars of T. ni determined the photosynthetic response to herbivory, which appeared to be mediated by the level of water stress associated with herbivore damage.

  4. Morphology and identification of first instars of the European and Mediterranean blowflies of forensic importance. Part II. Luciliinae

    DEFF Research Database (Denmark)

    Szpila, K.; Hall, M. J. R.; Pape, Thomas

    2013-01-01

    First instars of Lucilia ampullacea Villeneuve, Lucilia caesar Linnaeus, Lucilia cuprina Weidemann, Lucilia richardsi Collin, Lucilia sericata Meigen and Lucilia silvarum Meigen (Diptera: Calliphoridae) are thoroughly documented with scanning electron microscopy images, light microscopy photograp...... larva of L. richardsi is described for the first time and an identification key to the first instars of European species of Lucilia Robineau-Desvoidy of forensic importance is presented....

  5. PARASITISASI DAN KAPASITAS REPRODUKSI COTESIA FLAVIPES CAMERON (HYMENOPTERA: BRACONIDAE) PADA INANG DAN INSTAR YANG BERBEDA DI LABORATORIUM

    OpenAIRE

    Purnomo .

    2012-01-01

    Parasitization and reproductive capacity of Cotesia flavipes Cameron (Hymenoptaera: Braconidae) on different hosts and instar in laboratory. C. flavipes is an important parasitoid on sugar cane spotted borer, Chilo sacchariphagus Bojer.  The biology informations of C. flavipes is needed in order to make more effective as acontroling agent. The objectives of this research were to investigate the effect of host species (C. sacchariphagus, C. auricilius, Scirpophaga nivella) and different instar...

  6. Parasitisasi Dan Kapasitas Reproduksi Cotesia Flavipes Cameron (Hymenoptera: Braconidae) Pada Inang Dan Instar Yang Berbeda Di Laboratorium

    OpenAIRE

    Purnomo

    2006-01-01

    Parasitization and reproductive capacity of Cotesia flavipes Cameron (Hymenoptaera: Braconidae) on different hosts and instar in laboratory. C. flavipes is an important parasitoid on sugar cane spotted borer, Chilo sacchariphagus Bojer. The biology informations of C. flavipes is needed in order to make more effective as acontroling agent. The objectives of this research were to investigate the effect of host species (C. sacchariphagus, C. auricilius, Scirpophaga nivella) and different instar...

  7. Major salivary glands

    International Nuclear Information System (INIS)

    Mancuso, A.A.

    1985-01-01

    This chapter deals with two important features of treatment of malignant tumors of the parotid and submandibular gland: the lack of a satisfactory means of staging these lesions, and the all-important treatment considerations relative to the facial nerve in parotid gland malignancies. The imaging physician and the clinician should also consider that many suspected parotid mass lesions turn out to arise from structures extrinsic to the gland. The authors discuss in detail the sources of such mass lesions as well as how CT can be used to differentiate these from intrinsic lesions in the parotid and submandibular glands. Computed tomography and, perhaps in the near future, magnetic resonance imaging (MRI) will provide us with a means to diagnose these tumors earlier. This is especially true when studies are used in situations such as unexplained peripheral seventh nerve paralysis or in the early screening of patients with parotid or periparotid masses. Unfortunately, it is usually patient delay that leads to late diagnosis of palpable mass lesions in this region, and there is little that any imaging study can do to reduce this factor

  8. Determining the Number of Instars in Simulium quinquestriatum (Diptera: Simuliidae) Using k-Means Clustering via the Canberra Distance.

    Science.gov (United States)

    Yang, Yao Ming; Jia, Ruo; Xun, Hui; Yang, Jie; Chen, Qiang; Zeng, Xiang Guang; Yang, Ming

    2018-02-21

    Simulium quinquestriatum Shiraki (Diptera: Simuliidae), a human-biting fly that is distributed widely across Asia, is a vector for multiple pathogens. However, the larval development of this species is poorly understood. In this study, we determined the number of instars in this pest using three batches of field-collected larvae from Guiyang, Guizhou, China. The postgenal length, head capsule width, mandibular phragma length, and body length of 773 individuals were measured, and k-means clustering was used for instar grouping. Four distance measures-Manhattan, Euclidean, Chebyshev, and Canberra-were determined. The reported instar numbers, ranging from 4 to 11, were set as initial cluster centers for k-means clustering. The Canberra distance yielded reliable instar grouping, which was consistent with the first instar, as characterized by egg bursters and prepupae with dark histoblasts. Females and males of the last cluster of larvae were identified using Feulgen-stained gonads. Morphometric differences between the two sexes were not significant. Validation was performed using the Brooks-Dyar and Crosby rules, revealing that the larval stage of S. quinquestriatum is composed of eight instars.

  9. The implications of temperature-mediated plasticity in larval instar number for development within a marine invertebrate, the shrimp Palaemonetes varians.

    Directory of Open Access Journals (Sweden)

    Andrew Oliphant

    Full Text Available Variations in larval instar number are common among arthropods. Here, we assess the implications of temperature-mediated variations in larval instar number for larval development time, larval growth rates, and juvenile dry weight within the palaemonid shrimp, Palaemonetes varians. In contrast with previous literature, which focuses on terrestrial arthropods, particularly model and pest species often of laboratory lines, we use wild shrimp, which differ in their life history from previous models. Newly-hatched P. varians larvae were first reared at 5, 10, 17, 25, and 30 °C to assess their thermal scope for development. Larvae developed at 17, 25, and 30 °C. At higher temperatures, larvae developed through fewer larval instars. Two dominant developmental pathways were observed; a short pathway of four instars and a long pathway of five instars. Longer developmental pathways of six to seven instars were rarely observed (mostly at lower temperatures and consisted of additional instars as 'repeat' instars; i.e. little developmental advance over the preceding instar. To assess the implications of temperature-mediated variation in larval instar number, newly-hatched larvae were then reared at 15, 20, and 25 °C. Again, the proportion of larvae developing through four instars increased with temperature. At all temperatures, larval development time and juvenile dry weight were greater for larvae developing through five instars. Importantly, because of the increasing proportion of larvae developing through four instars with increasing temperature, larval traits associated with this pathway (reduced development time and juvenile dry weight became more dominant. As a consequence of increasing growth rate with temperature, and the shift in the proportion of larvae developing through four instars, juvenile dry weight was greatest at intermediate temperatures (20 °C. We conclude that at settlement P. varians juveniles do not follow the temperature-size rule

  10. The implications of temperature-mediated plasticity in larval instar number for development within a marine invertebrate, the shrimp Palaemonetes varians.

    Science.gov (United States)

    Oliphant, Andrew; Hauton, Chris; Thatje, Sven

    2013-01-01

    Variations in larval instar number are common among arthropods. Here, we assess the implications of temperature-mediated variations in larval instar number for larval development time, larval growth rates, and juvenile dry weight within the palaemonid shrimp, Palaemonetes varians. In contrast with previous literature, which focuses on terrestrial arthropods, particularly model and pest species often of laboratory lines, we use wild shrimp, which differ in their life history from previous models. Newly-hatched P. varians larvae were first reared at 5, 10, 17, 25, and 30 °C to assess their thermal scope for development. Larvae developed at 17, 25, and 30 °C. At higher temperatures, larvae developed through fewer larval instars. Two dominant developmental pathways were observed; a short pathway of four instars and a long pathway of five instars. Longer developmental pathways of six to seven instars were rarely observed (mostly at lower temperatures) and consisted of additional instars as 'repeat' instars; i.e. little developmental advance over the preceding instar. To assess the implications of temperature-mediated variation in larval instar number, newly-hatched larvae were then reared at 15, 20, and 25 °C. Again, the proportion of larvae developing through four instars increased with temperature. At all temperatures, larval development time and juvenile dry weight were greater for larvae developing through five instars. Importantly, because of the increasing proportion of larvae developing through four instars with increasing temperature, larval traits associated with this pathway (reduced development time and juvenile dry weight) became more dominant. As a consequence of increasing growth rate with temperature, and the shift in the proportion of larvae developing through four instars, juvenile dry weight was greatest at intermediate temperatures (20 °C). We conclude that at settlement P. varians juveniles do not follow the temperature-size rule; this is of

  11. Production of fine powder from silk by radiation

    International Nuclear Information System (INIS)

    Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu

    2000-01-01

    Silk fine power was prepared directly from silk fiber irradiated with an accelerated electron beam(EB). Irradiated silk fiber was well pulverized only by physical crushing using ball mill without any chemical pretreatment. Raw and degummed silk fibers were irradiated at ambient temperature in the dose range of 250-1000 kGy. Although unirradiated silk fibers were not pulverized at all, irradiated fibers were easily pulverized and showed higher conversion from fiber to powder for higher doses. The presence of oxygen in the irradiation atmosphere enhanced pulverization of silk fiber. Raw silk fibers were less pulverized compared to degummed ones. The electron microscope observation showed that the minimum particle size of silk powder obtained from fiber irradiated by 1000 kGy in oxygen was less than 10 microns. It was found that fibroin powder obtained in this work dissolved remarkably into cold water, thought unirradiated fibroin fiber had little solubility even in hot water. A typical soluble fraction was about 60% for fibroin powder obtained from fiber irradiated by 1000 kGy in oxygen. (author)

  12. Acute and Subacute Toxicity Evaluation of Corn Silk Extract.

    Science.gov (United States)

    Ha, Ae Wha; Kang, Hyeon Jung; Kim, Sun Lim; Kim, Myung Hwan; Kim, Woo Kyoung

    2018-03-01

    Many studies have reported therapeutic efficacy of corn silk extract. However, research on its toxicity and safe dose range is limited. Thus, the objective of this study was to determine the acute and subacute toxicity of corn silk extract in ICR mice. To determine acute toxicity, corn silk extract containing high levels of maysin was orally administered to mice at a dose of 0 or 2,000 mg/kg. Clinical symptoms, mortality, and body weight changes were recorded for 14 days. To determine subacute toxicity, corn silk extract was orally administered to mice over a 4-week period, and then body weight, water and food consumption, and organ weight were determined. In addition, urine and serum analyses were performed. In the acute toxicity study, no death or abnormal symptoms was observed in all treatment groups during the study period. Body weights did not show any significant change compared to those of the control group. Lethal dose of corn silk extract was estimated to be more than 2,000 mg/kg. In the 4-week subacute toxicity study, there was no corn silk extract related toxic effect on body weight, water intake, food consumption, urine parameters, clinical chemistry, or organ weight. Histopathological examination showed no abnormality related to the administration of corn silk extract at 500 mg/kg. The maximum non-toxic dose of corn silk extract containing high levels of maysin was found to be more than 500 mg/kg.

  13. Clay-Enriched Silk Biomaterials for Bone Formation

    Science.gov (United States)

    Mieszawska, Aneta J.; Llamas, Jabier Gallego; Vaiana, Christopher A.; Kadakia, Madhavi P.; Naik, Rajesh R.; Kaplan, David L.

    2011-01-01

    The formation of silk protein/clay composite biomaterials for bone tissue formation is described. Silk fibroin serves as an organic scaffolding material offering mechanical stability suitable for bone specific uses. Clay montmorillonite (Cloisite ® Na+) and sodium silicate are sources of osteoinductive silica-rich inorganic species, analogous to bioactive bioglass-like bone repair biomaterial systems. Different clay particle-silk composite biomaterial films were compared to silk films doped with sodium silicate as controls for support of human bone marrow derived mesenchymal stem cells (hMSCs) in osteogenic culture. The cells adhered and proliferated on the silk/clay composites over two weeks. Quantitative real-time RT-PCR analysis revealed increased transcript levels for alkaline phosphatase (ALP), bone sialoprotein (BSP), and collagen type 1 (Col I) osteogenic markers in the cells cultured on the silk/clay films in comparison to the controls. Early evidence for bone formation based on collagen deposition at the cell-biomaterial interface was also found, with more collagen observed for the silk films with higher contents of clay particles. The data suggest that the silk/clay composite systems may be useful for further study toward bone regenerative needs. PMID:21549864

  14. Re-opening the silk road to transform Chinese trade

    NARCIS (Netherlands)

    N. Mao (Ning); M.J. McAleer (Michael)

    2017-01-01

    textabstractUnder anti-globalization and isolationism, China is seeking to portray itself as a new leader for globalization under the banner of the Silk Road initiative. Meanwhile, China's traditional and comparatively advantaged industry, silk, has faced dire predicaments and challenges for long

  15. The failure mode of natural silk epoxy triggered composite tubes

    International Nuclear Information System (INIS)

    Eshkour, R A; Ariffin, A K; Zulkifli, R; Sulong, A B; Azhari, C H

    2012-01-01

    In this study the quasi static compression test over natural silk epoxy triggered composite tubes has been carried out, the natural silk epoxy composite tubes consist of 24 layer of woven natural silk as reinforcement and thermoset epoxy resin as matrix which both of them i e natural silk and epoxy have excellent mechanical properties More over the natural silk have better moisture resistance in comparison with other natural reinforcements, the length of tubes are 50, 80 and 120 mm The natural silk epoxy composite tubes are associated with an external trigger which includes 4 steel pieces welded on downside flat plate fixture The hand lay up fabrication method has been used to make the natural silk epoxy composite tubes Instron universal testing machine with 250 KN load capacity has been employed to accomplish this investigation The failure modes of natural silk epoxy triggered composite tubes has been investigated by representative photographs which has been taken by a high resolution camera(12 2 Mp) during the quasi static compression test, from the photographs is observed the failure modes is progressive local buckling

  16. Re-Opening the Silk Road to Transform Chinese Trade

    NARCIS (Netherlands)

    M. Ning (Mao); M.J. McAleer (Michael)

    2017-01-01

    textabstractUnder anti-globalization and isolationism, China is seeking to portray itself as a new leader for globalization under the banner of the Silk Road initiative. Meanwhile, China’s traditional and comparatively advantaged industry, silk, has faced dire predicaments and challenges for long

  17. Structure, composition and mechanical properties of the silk fibres of ...

    Indian Academy of Sciences (India)

    The silk egg case and orb web of spiders are elaborate structures that are assembled from a number of components. We analysed the structure, the amino acid and fibre compositions, and the tensile properties of the silk fibres of the egg case of Nephila clavata. SEM shows that the outer and inner covers of the egg case ...

  18. Production of fine powder from silk by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Ishida, Kazunari; Kamiishi, Youichi [Textile Research Institute of Gunma, Kiryu, Gunma (Japan)

    2000-03-01

    Silk fine power was prepared directly from silk fiber irradiated with an accelerated electron beam(EB). Irradiated silk fiber was well pulverized only by physical crushing using ball mill without any chemical pretreatment. Raw and degummed silk fibers were irradiated at ambient temperature in the dose range of 250-1000 kGy. Although unirradiated silk fibers were not pulverized at all, irradiated fibers were easily pulverized and showed higher conversion from fiber to powder for higher doses. The presence of oxygen in the irradiation atmosphere enhanced pulverization of silk fiber. Raw silk fibers were less pulverized compared to degummed ones. The electron microscope observation showed that the minimum particle size of silk powder obtained from fiber irradiated by 1000 kGy in oxygen was less than 10 microns. It was found that fibroin powder obtained in this work dissolved remarkably into cold water, thought unirradiated fibroin fiber had little solubility even in hot water. A typical soluble fraction was about 60% for fibroin powder obtained from fiber irradiated by 1000 kGy in oxygen. (author)

  19. Corn silk induces nitric oxide synthase in murine macrophages.

    Science.gov (United States)

    Kim, Kyung A; Choi, Sang Kyu; Choi, Hye Seon

    2004-12-31

    Corn silk has been purified as an anticoagulant previously and the active component is a polysaccharide with a molecular mass of 135 kDa. It activates murine macrophages to induce nitric oxide synthase (NOS) and generate substantial amounts of NO in time and dose-dependent manners. It was detectable first at 15 h after stimulation by corn silk, peaked at 24 h, and undetectable by 48 h. Induction of NOS is inhibited by pyrolidine dithiocarbamate (PDTC) and genistein, an inhibitor of nuclear factor kappa B (NF-kappaB) and tyrosine kinase, respectively, indicating that iNOS stimulated by corn silk is associated with tyrosine kinase and NF-kappaB signaling pathways. IkappaB-alpha degradation was detectible at 10 min, and the level was restored at 120 min after treatment of corn silk. Corn silk induced nuclear translocation of NF-kappaB by phosphorylation and degradation of IkappaB-alpha.

  20. Study on silk yellowing induced by gamma-irradiation

    International Nuclear Information System (INIS)

    Tsukada, Masuhiro; Aoki, Akira

    1985-01-01

    The changes in the yellow color of silk threads with total dose of irradiation applied were described and studied by a colorimetric method and by monochrome photography. The change into a yellow color of the specimen in the course of irradiation was clearly detected in photographs using filters, 2B and SC 56 under light conditions at the wavelength of 366 nm. The b/L value measured by colorimetry in undegummed and degummed silk fibers sharply increased in the early stage of irradiation. Yellow color indices (b/L) of the specimen subjected to gamma-irradiation continued to increase and the yellow color of the silk threads became more pronounced above a total dose of irradiation of 21 Mrad. The b/L value of the undegummed silk fiber which had deen irradiated was about 2 times that of the degummed silk fiber. (author)

  1. Optical surface profiling of orb-web spider capture silks

    Energy Technology Data Exchange (ETDEWEB)

    Kane, D M; Joyce, A M; Staib, G R [Department of Physics, Macquarie University, Sydney, NSW 2109 (Australia); Herberstein, M E, E-mail: deb.kane@mq.edu.a [Department of Biological Sciences, Macquarie University, Sydney, NSW 2109 (Australia)

    2010-09-15

    Much spider silk research to date has focused on its mechanical properties. However, the webs of many orb-web spiders have evolved for over 136 million years to evade visual detection by insect prey. It is therefore a photonic device in addition to being a mechanical device. Herein we use optical surface profiling of capture silks from the webs of adult female St Andrews cross spiders (Argiope keyserlingi) to successfully measure the geometry of adhesive silk droplets and to show a bowing in the aqueous layer on the spider capture silk between adhesive droplets. Optical surface profiling shows geometric features of the capture silk that have not been previously measured and contributes to understanding the links between the physical form and biological function. The research also demonstrates non-standard use of an optical surface profiler to measure the maximum width of a transparent micro-sized droplet (microlens).

  2. Optical surface profiling of orb-web spider capture silks

    International Nuclear Information System (INIS)

    Kane, D M; Joyce, A M; Staib, G R; Herberstein, M E

    2010-01-01

    Much spider silk research to date has focused on its mechanical properties. However, the webs of many orb-web spiders have evolved for over 136 million years to evade visual detection by insect prey. It is therefore a photonic device in addition to being a mechanical device. Herein we use optical surface profiling of capture silks from the webs of adult female St Andrews cross spiders (Argiope keyserlingi) to successfully measure the geometry of adhesive silk droplets and to show a bowing in the aqueous layer on the spider capture silk between adhesive droplets. Optical surface profiling shows geometric features of the capture silk that have not been previously measured and contributes to understanding the links between the physical form and biological function. The research also demonstrates non-standard use of an optical surface profiler to measure the maximum width of a transparent micro-sized droplet (microlens).

  3. Tumors of the sublingual gland

    DEFF Research Database (Denmark)

    Andreasen, Simon; Bjørndal, K; Agander, T K

    2016-01-01

    Tumors of the salivary glands are a heterogeneous group of diseases most often originating in the major salivary glands. Only a minor proportion of mainly malignant tumors arise in the sublingual gland. Due to the rarity of sublingual gland tumors (SGTs), little is known about the clinicopathologic...... are malignant, most frequently ACC with a high rate of metastatic spread. The diagnostic value of FNAC in SGTs seems inferior to what is found for other major salivary glands. DSS is determined by stage and T-stage and not by histopathological parameters. International collaboration is warranted to confirm...

  4. Effects of alkyl polyglycoside (APG) on Bombyx mori silk degumming and the mechanical properties of silk fibroin fibre

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Fei; Zhang, Yu-Qing, E-mail: sericult@suda.edu.cn

    2017-05-01

    Alkyl polyglycoside (APG), a nonionic surfactant, is often considered to be a green surfactant and is synthesized using glucose and long chain fatty alcohols. It is used as a degumming agent of Bombyx mori silk fibre in this study for the first time. We studied APG systematically in comparison to the traditional degumming methods, such as aqueous solutions of sodium carbonate (Na{sub 2}CO{sub 3}) and neutral soap (NS). After repeatedly boiling silk fibres in an aqueous solution of 0.25% APG three times for 30 min and using a bath ratio of 1:90–120 (g/mL), sericin was completely removed from the fibre. SDS-PAGE showed that the degumming in APG did not induce an evident breakage of the silk fibroin peptide chains, including the light chain and P25 protein. The tensile properties, thermal analysis, and scanning electron microscopic (SEM) observation of the degummed fibroin fibre all show that APG is a degumming agent similar to NS and far superior to Na{sub 2}CO{sub 3}. These results indicate that APG is an environment-friendly silk degumming/refining agent in the silk textile industry and in the manufacture of silk floss quilts. - Graphical abstract: APG has potential uses as a green degumming/refining reagent for silkworm cocoons or silk fibres in the silk industry and for sericulture production. Display Omitted.

  5. Multiscale mechanisms of nutritionally induced property variation in spider silks

    Science.gov (United States)

    Nobbs, Madeleine; Martens, Penny J.; Tso, I-Min; Chuang, Wei-Tsung; Chang, Chung-Kai; Sheu, Hwo-Shuenn

    2018-01-01

    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. PMID:29390013

  6. Sexual distinction between 5th instar nymphs of six species of Triatominae (Hemiptera, Reduviidae

    Directory of Open Access Journals (Sweden)

    João Aristeu da Rosa

    1992-06-01

    Full Text Available The aim of this paper is to present the analysis of sexual morphological differences observed in 5th instar nymphs of the following species: Panstrongylus megistus; Rhodnius neglectus; Triatoma brasiliensis; T. infestans; T. matogrosensis and T. tibiamaculata. Male and female nymphs were examined and photographed with a Scanning Electron Microscope. The 9th segment dimensions of dorsal and ventral faces were determined through a Profile Projector. Results and statistical analysis showed significant differences: the 9th sternite is significantly broader in male than female nymphs, while in five species; tergites in female nymphs are broad and in male are narrow.

  7. The influence of specific binding of collagen-silk chimeras to silk biomaterials on hMSC behavior.

    Science.gov (United States)

    An, Bo; DesRochers, Teresa M; Qin, Guokui; Xia, Xiaoxia; Thiagarajan, Geetha; Brodsky, Barbara; Kaplan, David L

    2013-01-01

    Collagen-like proteins in the bacteria Streptococcus pyogenes adopt a triple-helix structure with a thermal stability similar to that of animal collagens, can be expressed in high yield in Escherichia coli and can be easily modified through molecular biology techniques. However, potential applications for such recombinant collagens are limited by their lack of higher order structure to achieve the physical properties needed for most biomaterials. To overcome this problem, the S. pyogenes collagen domain was fused to a repetitive Bombyx mori silk consensus sequence, as a strategy to direct specific non-covalent binding onto solid silk materials whose superior stability, mechanical and material properties have been previously established. This approach resulted in the successful binding of these new collagen-silk chimeric proteins to silk films and porous scaffolds, and the binding affinity could be controlled by varying the number of repeats in the silk sequence. To explore the potential of collagen-silk chimera for regulating biological activity, integrin (Int) and fibronectin (Fn) binding sequences from mammalian collagens were introduced into the bacterial collagen domain. The attachment of bioactive collagen-silk chimeras to solid silk biomaterials promoted hMSC spreading and proliferation substantially in comparison to the controls. The ability to combine the biomaterial features of silk with the biological activities of collagen allowed more rapid cell interactions with silk-based biomaterials, improved regulation of stem cell growth and differentiation, as well as the formation of artificial extracellular matrices useful for tissue engineering applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Pituitary gland tumors

    International Nuclear Information System (INIS)

    Jesser, J.; Schlamp, K.; Bendszus, M.

    2014-01-01

    This article gives an overview of the most common tumors of the pituitary gland and the differential diagnostics with special emphasis on radiological diagnostic criteria. A selective search of the literature in PubMed was carried out. Pituitary adenomas constitute 10-15 % of all intracranial tumors and are the most common tumors of the sellar region. Tumors smaller than 1 cm in diameter are called microadenomas while those larger than 1 cm in diameter are called macroadenomas. Approximately 65 % of pituitary gland adenomas secrete hormones whereby approximately 50 % secrete prolactin, 10 % secrete growth hormone (somatotropin) and 6 % secrete corticotropin. Other tumors located in the sella turcica can also cause endocrinological symptoms, such as an oversecretion of pituitary hormone or pituitary insufficiency by impinging on the pituitary gland or its stalk. When tumors spread into the space cranial to the sella turcica, they can impinge on the optic chiasm and cause visual disorders. A common differential diagnosis of a sellar tumor is a craniopharyngeoma. In children up to 10 % of all intracranial tumors are craniopharyngeomas. Other differential diagnoses for sellar tumors are metastases, meningiomas, epidermoids and in rare cases astrocytomas, germinomas or Rathke cleft cysts As these tumors are located in an anatomically complex region of the skull base and are often very small, a highly focused imaging protocol is required. The currently favored modality is magnetic resonance imaging (MRI) with the administration of a contrast agent. The sellar region should be mapped in thin slices. In cases of suspected microadenoma the imaging protocol should also contain a sequence with dynamic contrast administration in order to assess the specific enhancement characteristics of the tumor and the pituitary gland. (orig.) [de

  9. [Pituitary gland tumors].

    Science.gov (United States)

    Jesser, J; Schlamp, K; Bendszus, M

    2014-10-01

    This article gives an overview of the most common tumors of the pituitary gland and the differential diagnostics with special emphasis on radiological diagnostic criteria. A selective search of the literature in PubMed was carried out. Pituitary adenomas constitute 10-15% of all intracranial tumors and are the most common tumors of the sellar region. Tumors smaller than 1 cm in diameter are called microadenomas while those larger than 1 cm in diameter are called macroadenomas. Approximately 65% of pituitary gland adenomas secrete hormones whereby approximately 50% secrete prolactin, 10% secrete growth hormone (somatotropin) and 6% secrete corticotropin. Other tumors located in the sella turcica can also cause endocrinological symptoms, such as an oversecretion of pituitary hormone or pituitary insufficiency by impinging on the pituitary gland or its stalk. When tumors spread into the space cranial to the sella turcica, they can impinge on the optic chiasm and cause visual disorders. A common differential diagnosis of a sellar tumor is a craniopharyngeoma. In children up to 10% of all intracranial tumors are craniopharyngeomas. Other differential diagnoses for sellar tumors are metastases, meningiomas, epidermoids and in rare cases astrocytomas, germinomas or Rathke cleft cysts As these tumors are located in an anatomically complex region of the skull base and are often very small, a highly focused imaging protocol is required. The currently favored modality is magnetic resonance imaging (MRI) with the administration of a contrast agent. The sellar region should be mapped in thin slices. In cases of suspected microadenoma the imaging protocol should also contain a sequence with dynamic contrast administration in order to assess the specific enhancement characteristics of the tumor and the pituitary gland.

  10. Inhibitory effect of corn silk on skin pigmentation.

    Science.gov (United States)

    Choi, Sang Yoon; Lee, Yeonmi; Kim, Sung Soo; Ju, Hyun Min; Baek, Ji Hwoon; Park, Chul-Soo; Lee, Dong-Hyuk

    2014-03-03

    In this study, the inhibitory effect of corn silk on melanin production was evaluated. This study was performed to investigate the inhibitory effect of corn silk on melanin production in Melan-A cells by measuring melanin production and protein expression. The corn silk extract applied on Melan-A cells at a concentration of 100 ppm decreased melanin production by 37.2% without cytotoxicity. This was a better result than arbutin, a positive whitening agent, which exhibited a 26.8% melanin production inhibitory effect at the same concentration. The corn silk extract did not suppress tyrosinase activity but greatly reduced the expression of tyrosinase in Melan-A cells. In addition, corn silk extract was applied to the human face with hyperpigmentation, and skin color was measured to examine the degree of skin pigment reduction. The application of corn silk extract on faces with hyperpigmentation significantly reduced skin pigmentation without abnormal reactions. Based on the results above, corn silk has good prospects for use as a material for suppressing skin pigmentation.

  11. Inhibitory Effect of Corn Silk on Skin Pigmentation

    Directory of Open Access Journals (Sweden)

    Sang Yoon Choi

    2014-03-01

    Full Text Available In this study, the inhibitory effect of corn silk on melanin production was evaluated. This study was performed to investigate the inhibitory effect of corn silk on melanin production in Melan-A cells by measuring melanin production and protein expression. The corn silk extract applied on Melan-A cells at a concentration of 100 ppm decreased melanin production by 37.2% without cytotoxicity. This was a better result than arbutin, a positive whitening agent, which exhibited a 26.8% melanin production inhibitory effect at the same concentration. The corn silk extract did not suppress tyrosinase activity but greatly reduced the expression of tyrosinase in Melan-A cells. In addition, corn silk extract was applied to the human face with hyperpigmentation, and skin color was measured to examine the degree of skin pigment reduction. The application of corn silk extract on faces with hyperpigmentation significantly reduced skin pigmentation without abnormal reactions. Based on the results above, corn silk has good prospects for use as a material for suppressing skin pigmentation.

  12. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    Energy Technology Data Exchange (ETDEWEB)

    Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A [Department of Tissue Regeneration, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Hedhammar, My; Johansson, Jan [Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, the Biomedical Centre, Box 575, 751 23 Uppsala (Sweden); Blom, Tobias; Leifer, Klaus [Department of Engineering Sciences, Uppsala University, Box 534, S-751 21 Uppsala (Sweden)

    2010-08-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  13. The processing and heterostructuring of silk with light

    Science.gov (United States)

    Sidhu, Mehra S.; Kumar, Bhupesh; Singh, Kamal P.

    2017-09-01

    Spider silk is a tough, elastic and lightweight biomaterial, although there is a lack of tools available for non-invasive processing of silk structures. Here we show that nonlinear multiphoton interactions of silk with few-cycle femtosecond pulses allow the processing and heterostructuring of the material in ambient air. Two qualitatively different responses, bulging by multiphoton absorption and plasma-assisted ablation, are observed for low- and high-peak intensities, respectively. Plasma ablation allows us to make localized nanocuts, microrods, nanotips and periodic patterns with minimal damage while preserving molecular structure. The bulging regime facilitates confined bending and microwelding of silk with materials such as metal, glass and Kevlar with strengths comparable to pristine silk. Moreover, analysis of Raman bands of microwelded joints reveals that the polypeptide backbone remains intact while perturbing its weak hydrogen bonds. Using this approach, we fabricate silk-based functional topological microstructures, such as Mobiüs strips, chiral helices and silk-based sensors.

  14. The processing and heterostructuring of silk with light.

    Science.gov (United States)

    Sidhu, Mehra S; Kumar, Bhupesh; Singh, Kamal P

    2017-09-01

    Spider silk is a tough, elastic and lightweight biomaterial, although there is a lack of tools available for non-invasive processing of silk structures. Here we show that nonlinear multiphoton interactions of silk with few-cycle femtosecond pulses allow the processing and heterostructuring of the material in ambient air. Two qualitatively different responses, bulging by multiphoton absorption and plasma-assisted ablation, are observed for low- and high-peak intensities, respectively. Plasma ablation allows us to make localized nanocuts, microrods, nanotips and periodic patterns with minimal damage while preserving molecular structure. The bulging regime facilitates confined bending and microwelding of silk with materials such as metal, glass and Kevlar with strengths comparable to pristine silk. Moreover, analysis of Raman bands of microwelded joints reveals that the polypeptide backbone remains intact while perturbing its weak hydrogen bonds. Using this approach, we fabricate silk-based functional topological microstructures, such as Mobiüs strips, chiral helices and silk-based sensors.

  15. Binding Quantum Dots to Silk Biomaterials for Optical Sensing

    Directory of Open Access Journals (Sweden)

    Disi Lu

    2015-01-01

    Full Text Available Quantum dots (QDs, have great potential for fabricating optical sensing devices and imaging biomaterial degradation in vivo. In the present study, 2-mercaptoethylamine- (MEA- and mercaptopropionic acid- (MPA- capped CdTe-QDs were physically incorporated in silk films that contained a high content (>30% of crystalline beta-sheet structure. The beta-sheets were induced by the addition of glycerol, water annealing, glycerol/annealing, or treatment with methanol. Incorporation of QDs did not influence the formation of beta-sheets. When the films were extracted with water, most QDs remained associated with the silk, based on the retention of photoluminescence in the silk films and negligible photoluminescence in the extracts. Compared to the solution state, photoluminescence intensity significantly decreased for MEA-QDs but not for MPA-QDs in the silk films, while the emission maximum blue shifted (≈4 nm slightly for both. Further film digestion using protease XIV, alpha-chymotrypsin, and the combination of the two proteases suggested that QDs may be bound to the silk beta-sheet regions but not the amorphous regions. QDs photoluminescence in silk films was quenched when the concentration of hydrogen peroxide (H2O2 was above 0.2-0.3 mM, indicating the QDs-incorporated silk films can be used to report oxidation potential in solution.

  16. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    International Nuclear Information System (INIS)

    Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A; Hedhammar, My; Johansson, Jan; Blom, Tobias; Leifer, Klaus

    2010-01-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

  17. Microbial gut diversity of Africanized and European honey bee larval instars.

    Directory of Open Access Journals (Sweden)

    Svjetlana Vojvodic

    Full Text Available The first step in understanding gut microbial ecology is determining the presence and potential niche breadth of associated microbes. While the core gut bacteria of adult honey bees is becoming increasingly apparent, there is very little and inconsistent information concerning symbiotic bacterial communities in honey bee larvae. The larval gut is the target of highly pathogenic bacteria and fungi, highlighting the need to understand interactions between typical larval gut flora, nutrition and disease progression. Here we show that the larval gut is colonized by a handful of bacterial groups previously described from guts of adult honey bees or other pollinators. First and second larval instars contained almost exclusively Alpha 2.2, a core Acetobacteraceae, while later instars were dominated by one of two very different Lactobacillus spp., depending on the sampled site. Royal jelly inhibition assays revealed that of seven bacteria occurring in larvae, only one Neisseriaceae and one Lactobacillus sp. were inhibited. We found both core and environmentally vectored bacteria with putatively beneficial functions. Our results suggest that early inoculation by Acetobacteraceae may be important for microbial succession in larvae. This assay is a starting point for more sophisticated in vitro models of nutrition and disease resistance in honey bee larvae.

  18. A novel electrospun silk fibroin/hydroxyapatite hybrid nanofibers

    International Nuclear Information System (INIS)

    Ming, Jinfa; Zuo, Baoqi

    2012-01-01

    A novel electrospinning of silk fibroin/hydroxyapatite hybrid nanofibers with different composition ratios was performed with methanoic acid as a spinning solvent. The silk fibroin/hydroxyapatite hybrids containing up to 30% hydroxyapatite nanoparticles could be electrospun into the continuous fibrous structure. The electrospun silk fibroin/hydroxyapatite hybrid nanofibers showed bigger diameter and wider diameter distribution than pure silk fibroin nanofibers, and the average diameter gradually increased from 95 to 582 nm. At the same time, the secondary structure of silk fibroin/hydroxyapatite nanofibers was characterized by X-ray diffraction, Fourier transform infrared analysis, and DSC measurement. Comparing with the pure silk fibroin nanofibers, the crystal structure of silk fibroin was mainly amorphous structure in the hybrid nanofibers. X-ray diffraction results demonstrated the hydroxyapatite crystalline nature remained as evidenced from the diffraction planes (002), (211), (300), and (202) of the hydroxyapatite crystallites, which was also confirmed by Fourier transform infrared analysis. The thermal behavior of hybrid nanofibers exhibited the endothermic peak of moisture evaporation ranging from 86 to 113 °C, and the degradation peak at 286 °C appeared. The SF/HAp nanofibers mats containing 30% HAp nanoparticles showed higher breaking tenacity and extension at break for 1.1688 ± 0.0398 MPa and 6.55 ± 1.95%, respectively. Therefore, the electrospun silk fibroin/hydroxyapatite hybrid nanofibers should be provided potentially useful options for the fabrication of biomaterial scaffolds for bone tissue engineering. -- Highlights: ► The novel SF/HAp nanofibers were directly prepared by electrospinning method. ► The nanofiber diameter had significant related to the content of HAp. ► The crystal structure of silk fibroin was mainly amorphous structure in the hybrid nanofibers. ► The HAp crystals existing in the hybrid nanofibers were characterized

  19. Formation of different gold nanostructures by silk nanofibrils

    International Nuclear Information System (INIS)

    Fang, Guangqiang; Yang, Yuhong; Yao, Jinrong; Shao, Zhengzhong; Chen, Xin

    2016-01-01

    Metal nanostructures that have unique size- and shape-dependent electronic, optical and chemical properties gain more and more attention in modern science and technology. In this article, we show the possibility that we are able to obtain different gold nanostructures simply with the help of silk nanofibrils. We demonstrate that only by varying the pH of the reaction solution, we get gold nanoparticles, nano-icosahedrons, nanocubes, and even microplates. Particularly, we develop a practical method for the preparation of gold microplates in acid condition in the presence of silk nanofibrils, which is impossible by using other forms of silk protein. We attribute the role of silk nanofibrils in the formation of gold nanostructure to their reduction ability from several specific amino acid residues, and the suitable structural anisotropic features to sustain the crystal growth after the reduction process. Although the main purpose of this article is to demonstrate that silk nanofibrils are able to mediate the formation of different gold nanostructure, we show the potential applications of these resulting gold nanostructures, such as surface-enhanced Raman scattering (SERS) and photothermal transformation effect, as same as those produced by other methods. In conclusion, we present in this communication a facile and green synthesis route to prepare various gold nanostructures with silk nanofibrils by simply varying pH in the reaction system, which has remarkable advantages in future biomedical applications. - Highlights: • Different Au nanostructures can be obtained by a facile and green protein reduction method. • Silk nanofibrils serve as both reductant and template in the formation of Au nanostructures. • Different Au nanostructures can be obtained simply by regulating the pH in the medium. • Large Au microplates can be obtained with a cheap, abundant, sustainable silk protein. • Silk/Au hybrid nanocomposites show potential application in SERS and

  20. The effects of corn silk on glycaemic metabolism

    Directory of Open Access Journals (Sweden)

    Han Linna

    2009-11-01

    Full Text Available Abstract Background Corn silk contains proteins, vitamins, carbohydrates, Ca, K, Mg and Na salts, fixed and volatile oils, steroids such as sitosterol and stigmasterol, alkaloids, saponins, tannins, and flavonoids. Base on folk remedies, corn silk has been used as an oral antidiabetic agent in China for decades. However, the hypoglycemic activity of it has not yet been understood in terms of modern pharmacological concepts. The purpose of this study is to investigate the effects of corn silk on glycaemic metabolism. Methods Alloxan and adrenalin induced hyperglycemic mice were used in the study. The effects of corn silk on blood glucose, glycohemoglobin (HbA1c, insulin secretion, damaged pancreatic β-cells, hepatic glycogen and gluconeogenesis in hyperglycemic mice were studied respectively. Results After the mice were orally administered with corn silk extract, the blood glucose and the HbA1c were significantly decreased in alloxan-induced hyperglycemic mice (p 0.05. Although corn silk extract increased the level of hepatic glycogen in the alloxan-induced hyperglycemic mice, there was no significant difference between them and that of the control group(p > 0.05. Conclusion Corn silk extract markedly reduced hyperglycemia in alloxan-induced diabetic mice. The action of corn silk extract on glycaemic metabolism is not via increasing glycogen and inhibiting gluconeogenesis but through increasing insulin level as well as recovering the injured β-cells. The results suggest that corn silk extract may be used as a hypoglycemic food or medicine for hyperglycemic people in terms of this modern pharmacological study.

  1. Formation of different gold nanostructures by silk nanofibrils

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Guangqiang [State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433 (China); Yang, Yuhong [Research Centre for Analysis and Measurement, Fudan University, Shanghai 200433 (China); Yao, Jinrong; Shao, Zhengzhong [State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433 (China); Chen, Xin, E-mail: chenx@fudan.edu.cn [State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, 200433 (China)

    2016-07-01

    Metal nanostructures that have unique size- and shape-dependent electronic, optical and chemical properties gain more and more attention in modern science and technology. In this article, we show the possibility that we are able to obtain different gold nanostructures simply with the help of silk nanofibrils. We demonstrate that only by varying the pH of the reaction solution, we get gold nanoparticles, nano-icosahedrons, nanocubes, and even microplates. Particularly, we develop a practical method for the preparation of gold microplates in acid condition in the presence of silk nanofibrils, which is impossible by using other forms of silk protein. We attribute the role of silk nanofibrils in the formation of gold nanostructure to their reduction ability from several specific amino acid residues, and the suitable structural anisotropic features to sustain the crystal growth after the reduction process. Although the main purpose of this article is to demonstrate that silk nanofibrils are able to mediate the formation of different gold nanostructure, we show the potential applications of these resulting gold nanostructures, such as surface-enhanced Raman scattering (SERS) and photothermal transformation effect, as same as those produced by other methods. In conclusion, we present in this communication a facile and green synthesis route to prepare various gold nanostructures with silk nanofibrils by simply varying pH in the reaction system, which has remarkable advantages in future biomedical applications. - Highlights: • Different Au nanostructures can be obtained by a facile and green protein reduction method. • Silk nanofibrils serve as both reductant and template in the formation of Au nanostructures. • Different Au nanostructures can be obtained simply by regulating the pH in the medium. • Large Au microplates can be obtained with a cheap, abundant, sustainable silk protein. • Silk/Au hybrid nanocomposites show potential application in SERS and

  2. Inhibitory Effect of Corn Silk on Skin Pigmentation

    OpenAIRE

    Sang Yoon Choi; Yeonmi Lee; Sung Soo Kim; Hyun Min Ju; Ji Hwoon Baek; Chul-Soo Park; Dong-Hyuk Lee

    2014-01-01

    In this study, the inhibitory effect of corn silk on melanin production was evaluated. This study was performed to investigate the inhibitory effect of corn silk on melanin production in Melan-A cells by measuring melanin production and protein expression. The corn silk extract applied on Melan-A cells at a concentration of 100 ppm decreased melanin production by 37.2% without cytotoxicity. This was a better result than arbutin, a positive whitening agent, which exhibited a 26.8% melanin prod...

  3. Spider silk reinforced by graphene or carbon nanotubes

    Science.gov (United States)

    Lepore, Emiliano; Bosia, Federico; Bonaccorso, Francesco; Bruna, Matteo; Taioli, Simone; Garberoglio, Giovanni; Ferrari, Andrea C.; Pugno, Nicola Maria

    2017-09-01

    Spider silk has promising mechanical properties, since it conjugates high strength (~1.5 GPa) and toughness (~150 J g-1). Here, we report the production of silk incorporating graphene and carbon nanotubes by spider spinning, after feeding spiders with the corresponding aqueous dispersions. We observe an increment of the mechanical properties with respect to pristine silk, up to a fracture strength ~5.4 GPa and a toughness modulus ~1570 J g-1. This approach could be extended to other biological systems and lead to a new class of artificially modified biological, or ‘bionic’, materials.

  4. The effect of within-instar development on tracheal diameter and hypoxia-inducible factors α and β in the tobacco hornworm, Manduca sexta.

    Science.gov (United States)

    Lundquist, Taylor A; Kittilson, Jeffrey D; Ahsan, Rubina; Greenlee, Kendra J

    2017-12-12

    As insects grow within an instar, body mass increases, often more than doubling. The increase in mass causes an increase in metabolic rate and hence oxygen demand. However, the insect tracheal system is hypothesized to increase only after molting and may be compressed as tissues grow within an instar. The increase in oxygen demand in the face of a potentially fixed or decreasing supply could result in hypoxia as insects near the end of an instar. To test these hypotheses, we first used synchrotron X-ray imaging to determine how diameters of large tracheae change within an instar and after molting to the next instar in the tobacco hornworm, Manduca sexta. Large tracheae did not increase in diameter within the first, second, third, and fourth instars, but increased upon molting. To determine if insects are hypoxic at the end of instars, we used the presence of hypoxia-inducible factors (HIFs) as an index. HIF-α and HIF-β dimerize in hypoxia and act as a transcription factor that turns on genes that will increase oxygen delivery. We sequenced both of these genes and measured their mRNA levels at the beginning and end of each larval instar. Finally, we obtained an antibody to HIF-α and measured protein expression during the same time. Both mRNA and protein levels of HIFs were increased at the end of most instars. These data support the hypothesis that some insects may experience hypoxia at the end of an instar, which could be a signal for molting. As caterpillars grow within an instar, major tracheae do not increase in size, while metabolic demand increases. At the same life stages, caterpillars increased expression of hypoxia inducible factors, suggesting that they become hypoxic near the end of an instar. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Plasticity in Major Ampullate Silk Production in Relation to Spider Phylogeny and Ecology

    Science.gov (United States)

    Boutry, Cecilia; Řezáč, Milan; Blackledge, Todd Alan

    2011-01-01

    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. PMID:21818328

  6. Plasticity in major ampullate silk production in relation to spider phylogeny and ecology.

    Directory of Open Access Journals (Sweden)

    Cecilia Boutry

    Full Text Available 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.

  7. Fluorescence Imaging of Posterior Spiracles from Second and Third Instars of Forensically Important Chrysomya rufifacies (Diptera: Calliphoridae).

    Science.gov (United States)

    Flores, Danielle; Miller, Amy L; Showman, Angelique; Tobita, Caitlyn; Shimoda, Lori M N; Sung, Carl; Stokes, Alexander J; Tomberlin, Jeffrey K; Carter, David O; Turner, Helen

    2016-11-01

    Entomological protocols for aging blowfly (Diptera: Calliphoridae) larvae to estimate the time of colonization (TOC) are commonly used to assist in death investigations. While the methodologies for analyzing fly larvae differ, most rely on light microscopy, genetic analysis, or, more rarely, electron microscopy. This pilot study sought to improve resolution of larval stage in the forensically important blowfly Chrysomya rufifacies using high-content fluorescence microscopy and biochemical measures of developmental marker proteins. We established fixation and mounting protocols, defined a set of measurable morphometric criteria and captured developmental transitions of 2nd instar to 3rd instar using both fluorescence microscopy and anti-ecdysone receptor Western blot analysis. The data show that these instars can be distinguished on the basis of robust, nonbleaching, autofluorescence of larval posterior spiracles. High-content imaging techniques using confocal microscopy, combined with morphometric and biochemical techniques, may therefore aid forensic entomologists in estimating TOC. © 2016 American Academy of Forensic Sciences.

  8. Morphology of second and third instars of Chrysomya villeneuvi Patton (Diptera: Calliphoridae), a fly species of forensic importance.

    Science.gov (United States)

    Sukontason, Kom; Sukontason, Kabkaew L; Piangjai, Somsak; Narongchai, Paitoon; Samai, Wirachai; Boonchu, Noppawan; Sripakdee, Duanghatai; Ngern-Klun, Radchadawan; Siriwattanarungsee, Sirisuda

    2005-11-25

    The morphology of the second and third instars of Chrysomya villeneuvi Patton, a fly species of forensic importance, was presented by use of light microscopy. Both instars were of hairy appearance, bearing elongated tubercles along the abdominal and caudal segments. The anterior spiracle had 13-15 papillae. Minute dark spots were observed to thoroughly cover the tubercle's surface, with 4-6 strong dark tips. Regarding the third instar, the intersegmental spines between the prothorax and mesothorax were heavily pigmented. The posterior spiracle had a thick and heavily pigmented incomplete peritreme. The surface and tip of the tubercles was covered with heavily pigmented sharp spines. The integument of the body was covered with numerous distinct net-like patches. A comparison with another well-known hairy maggot, Chrysomya rufifacies (Macquart), was discussed.

  9. [The functioning of the mitochondrial system and respiration at the 5th larval instar in Pieris brassicae (Lepidoptera)].

    Science.gov (United States)

    Guillet, C; Fourche, J

    1980-01-01

    The profiles of respiratory rate, total proteins, mitochondrial proteins and mitochondrial activity have been described during the fifth instar of Pieris brassicae reared either under long-day or short-day photoperiod. There was no fundamental difference per unit of live weight between the long-day and short-day larvae. The biochemical characteristics of the larval mitochondria have been described, and the mitochondria were shown to oxidize succinate better than alpha-glycerophosphate. Two periods during the fifth instar were related to mitochondrial activity. During the first one, this specific activity was high during 50 to 60 p. 100 of the instar; it then decreased. This alteration was superimposed on changes in the hormonal balance. It is shown that the respiratory rate was not only a passive response to the energy demand, and that specific mitochondrial activity must be considered as a parameter of the development program.

  10. Fluorescence Imaging of Posterior Spiracles from Second and Third Instars of Forensically-important Chrysomya rufifacies (Diptera: Calliphoridae)*

    Science.gov (United States)

    Flores, Danielle; Miller, Amy L.; Showman, Angelique; Tobita, Caitlyn; Shimoda, Lori M.N.; Sung, Carl; Stokes, Alexander J.; Tomberlin, Jeffrey K.; Carter, David O.; Turner, Helen

    2016-01-01

    Entomological protocols for aging blow fly (Diptera: Calliphoridae) larvae to estimate the time of colonization (TOC) are commonly used to assist in death investigations. While the methodologies for analysing fly larvae differ, most rely on light microscopy, genetic analysis or, more rarely, electron microscopy. This pilot study sought to improve resolution of larval stage in the forensically-important blow fly Chrysomya rufifacies using high-content fluorescence microscopy and biochemical measures of developmental marker proteins. We established fixation and mounting protocols, defined a set of measurable morphometric criteria and captured developmental transitions of 2nd instar to 3rd instar using both fluorescence microscopy and anti-ecdysone receptor Western blot analysis. The data show that these instars can be distinguished on the basis of robust, non-bleaching, autofluorescence of larval posterior spiracles. High content imaging techniques using confocal microscopy, combined with morphometric and biochemical techniques, may therefore aid forensic entomologists in estimating TOC. PMID:27706817

  11. PARASITISASI DAN KAPASITAS REPRODUKSI COTESIA FLAVIPES CAMERON (HYMENOPTERA: BRACONIDAE PADA INANG DAN INSTAR YANG BERBEDA DI LABORATORIUM

    Directory of Open Access Journals (Sweden)

    Purnomo .

    2012-02-01

    Full Text Available Parasitization and reproductive capacity of Cotesia flavipes Cameron (Hymenoptaera: Braconidae on different hosts and instar in laboratory. C. flavipes is an important parasitoid on sugar cane spotted borer, Chilo sacchariphagus Bojer.  The biology informations of C. flavipes is needed in order to make more effective as acontroling agent. The objectives of this research were to investigate the effect of host species (C. sacchariphagus, C. auricilius, Scirpophaga nivella and different instar on parasitization and reproductive capacity of C. flavipes. The results showed that the best host for                    C.  flavipes is  C. sacchariphagus and at fifth instar of  C. sacchariphagus.

  12. Chitin in the Silk Gland Ducts of the Spider Nephila edulis and the Silkworm Bombyx mori

    Science.gov (United States)

    Davies, Gwilym J. G.; Knight, David P.; Vollrath, Fritz

    2013-01-01

    Here we report the detection and localisation of chitin in the cuticle of the spinning ducts of both the spider Nephila edulis and the silkworm Bombyx mori. Our observations demonstrate that the duct walls of both animals contain chitin notwithstanding totally independent evolutionary pathways of the systems. We conclude that chitin may well be an essential component for the construction of spinning ducts; we further conclude that in both species chitin may indicate the evolutionary origin of the spinning ducts. PMID:24015298

  13. Conductive Au nanowires regulated by silk fibroin nanofibers

    Science.gov (United States)

    Dong, Bo-Ju; Lu, Qiang

    2014-03-01

    Conductive Au-biopolymer composites have promising applications in tissue engineering such as nerve tissue regeneration. In this study, silk fibroin nanofibers were formed in aqueous solution by regulating silk self-assembly process and then used as template for Au nanowire fabrication. We performed the synthesis of Au seeds by repeating the seeding cycles for several times in order to increase the density of Au seeds on the nanofibers. After electroless plating, densely decorated Au seeds grew into irregularly shaped particles following silk nanofiber to fill the gaps between particles and finally form uniform continuous nanowires. The conductive property of the Au-silk fibroin nanowires was studied with current-voltage ( I-V) measurement. A typical ohmic behavior was observed, which highlighted their potential applications in nerve tissue regeneration.

  14. Silk-polypyrrole biocompatible actuator performance under biologically relevant conditions

    Science.gov (United States)

    Hagler, Jo'elen; Peterson, Ben; Murphy, Amanda; Leger, Janelle

    Biocompatible actuators that are capable of controlled movement and can function under biologically relevant conditions are of significant interest in biomedical fields. Previously, we have demonstrated that a composite material of silk biopolymer and the conducting polymer polypyrrole (PPy) can be formed into a bilayer device that can bend under applied voltage. Further, these silk-PPy composites can generate forces comparable to human muscle (>0.1 MPa) making them ideal candidates for interfacing with biological tissues. Here silk-PPy composite films are tested for performance under biologically relevant conditions including exposure to a complex protein serum and biologically relevant temperatures. Free-end bending actuation performance, current response, force generation and, mass degradation were investigated . Preliminary results show that when exposed to proteins and biologically relevant temperatures, these silk-PPy composites show minimal degradation and are able to generate forces and conduct currents comparable to devices tested under standard conditions. NSF.

  15. Synthetic Adhesive Attachment Discs based on Spider Pyriform Silk Architecture

    Science.gov (United States)

    Jain, Dharamdeep; Sahni, Vasav; Dhinojwala, Ali

    2014-03-01

    Among the variety of silks produced by spiders, pyriform silk is used in conjunction with the dragline silk to attach webs to different surfaces. Cob weaver spiders employ different architectural patterns to utilize the pyriform silk and form attachment joints with each pattern having a characteristic adhesive performance. The staple pin architecture is a one of the strongest attachment designs employed by spiders to attach their webs. Here we use a synthetic approach to create the a similar patterned architecture attachment discs on aluminum substrate using thermoplastic polyurethane. Measurable pull off forces are generated when the synthetic discs are peeled off a surface. This innovative adhesive strategy can be a source of design in various biomedical applications. Financial Support from National Science Foundation.

  16. Biomimetic calcium phosphate coatings on recombinant spider silk fibres

    NARCIS (Netherlands)

    Yang, Liang; Hedhammar, My; Blom, Tobias; Leifer, Klaus; Johansson, Jan; Habibovic, Pamela; van Blitterswijk, Clemens

    2010-01-01

    Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently,

  17. Bioprospection of immature salivary glands of Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae).

    Science.gov (United States)

    Caleffe, Ronaldo Roberto Tait; de Oliveira, Stefany Rodrigues; Gigliolli, Adriana Aparecida Sinópolis; Ruvolo-Takasusuki, Maria Claudia Colla; Conte, Helio

    2018-06-08

    Larval therapy (LT) comprises the application of sterile Calliphoridae larvae for wound debridement, disinfection, and healing in humans and animals. Larval digestion plays a key role in LT, where the salivary glands and gut produce and secrete proteolytic and antimicrobial substances. The objective of this work was to bioprospect the salivary glands of Chrysomya megacephala (Fabricius, 1794) larvae, using ultrastructural, morphological, and histological observations, and the total protein electrophoretic profile. The salivary glands present a deferent duct, originating from the buccal cavity, which bifurcates into efferent ducts that insert through a slight dilatation to a pair of tubular-shaped tissues, united in the region of fat cells. Histologically, the secretion had protein characteristics. Cell cytoplasm presented numerous free ribosomes, autophagic vacuoles, spherical and elongated mitochondria, atypical Golgi complexes, and dilated rough endoplasmic reticulum. In the apical cytoplasm, secretory granules and microvilli secretions demonstrated intense protein synthesis, basal cytoplasm with trachea insertions, and numerous mitochondria. The present work described the ultrastructure and morphology of C. megacephala third instar salivary glands, confirming intense protein synthesis and the molecular weight of soluble proteins. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Silk scaffolds in bone tissue engineering: An overview.

    Science.gov (United States)

    Bhattacharjee, Promita; Kundu, Banani; Naskar, Deboki; Kim, Hae-Won; Maiti, Tapas K; Bhattacharya, Debasis; Kundu, Subhas C

    2017-11-01

    Bone tissue plays multiple roles in our day-to-day functionality. The frequency of accidental bone damage and disorder is increasing worldwide. Moreover, as the world population continues to grow, the percentage of the elderly population continues to grow, which results in an increased number of bone degenerative diseases. This increased elderly population pushes the need for artificial bone implants that specifically employ biocompatible materials. A vast body of literature is available on the use of silk in bone tissue engineering. The current work presents an overview of this literature from materials and fabrication perspective. As silk is an easy-to-process biopolymer; this allows silk-based biomaterials to be molded into diverse forms and architectures, which further affects the degradability. This makes silk-based scaffolds suitable for treating a variety of bone reconstruction and regeneration objectives. Silk surfaces offer active sites that aid the mineralization and/or bonding of bioactive molecules that facilitate bone regeneration. Silk has also been blended with a variety of polymers and minerals to enhance its advantageous properties or introduce new ones. Several successful works, both in vitro and in vivo, have been reported using silk-based scaffolds to regenerate bone tissues or other parts of the skeletal system such as cartilage and ligament. A growing trend is observed toward the use of mineralized and nanofibrous scaffolds along with the development of technology that allows to control scaffold architecture, its biodegradability and the sustained releasing property of scaffolds. Further development of silk-based scaffolds for bone tissue engineering, taking them up to and beyond the stage of human trials, is hoped to be achieved in the near future through a cross-disciplinary coalition of tissue engineers, material scientists and manufacturing engineers. The state-of-art of silk biomaterials in bone tissue engineering, covering their wide

  19. Direct transfer of subwavelength plasmonic nanostructures on bioactive silk films.

    Science.gov (United States)

    Lin, Dianmin; Tao, Hu; Trevino, Jacob; Mondia, Jessica P; Kaplan, David L; Omenetto, Fiorenzo G; Dal Negro, Luca

    2012-11-27

    By a reusable transfer fabrication technique, we demonstrate high-fidelity fabrication of metal nanoparticles, optical nanoantennas, and nanohole arrays directly on a functional silk biopolymer. The ability to reproducibly pattern silk biopolymers with arbitrarily complex plasmonic arrays is of importance for a variety of applications in optical biosensing, tissue engineering, cell biology, and the development of novel bio-optoelectronic medical devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. [Study on the chemical constituents of flavones from corn silk].

    Science.gov (United States)

    Zhang, Hui-en; Xu, De-ping

    2007-02-01

    The three flavones were isolated from water extracts of corn silk by chromatography on macroporous resin, polyamide, ODS and Sephadex LH-20. Three compounds were identified as formononetin (7-hydroxy-4'-methoxyisoflavone) ( I ) ,2"-O-alpha-L-rham-nosyl-6-C-( 3-deoxyglucosyl) -3 '-methoxyluteolin( II ) ,2"-O-alpha-L-rhamnosyl-6-C-( 6-deoxy-ax-5-methyl-xylo-hexos-4-ulosyl) -3'-methoxyluteolin( II ). Compounds ( I ) and ( II ) were isolated from the corn silk for the first time.

  1. Nanostructure and molecular mechanics of spider dragline silk protein assemblies

    Science.gov (United States)

    Keten, Sinan; Buehler, Markus J.

    2010-01-01

    Spider silk is a self-assembling biopolymer that outperforms most known materials in terms of its mechanical performance, despite its underlying weak chemical bonding based on H-bonds. While experimental studies have shown that the molecular structure of silk proteins has a direct influence on the stiffness, toughness and failure strength of silk, no molecular-level analysis of the nanostructure and associated mechanical properties of silk assemblies have been reported. Here, we report atomic-level structures of MaSp1 and MaSp2 proteins from the Nephila clavipes spider dragline silk sequence, obtained using replica exchange molecular dynamics, and subject these structures to mechanical loading for a detailed nanomechanical analysis. The structural analysis reveals that poly-alanine regions in silk predominantly form distinct and orderly beta-sheet crystal domains, while disorderly regions are formed by glycine-rich repeats that consist of 31-helix type structures and beta-turns. Our structural predictions are validated against experimental data based on dihedral angle pair calculations presented in Ramachandran plots, alpha-carbon atomic distances, as well as secondary structure content. Mechanical shearing simulations on selected structures illustrate that the nanoscale behaviour of silk protein assemblies is controlled by the distinctly different secondary structure content and hydrogen bonding in the crystalline and semi-amorphous regions. Both structural and mechanical characterization results show excellent agreement with available experimental evidence. Our findings set the stage for extensive atomistic investigations of silk, which may contribute towards an improved understanding of the source of the strength and toughness of this biological superfibre. PMID:20519206

  2. Effects of buprofezin on the ultrastructure of the third instar cuticle of the insect Trialeurodes vaporariorum.

    Science.gov (United States)

    De Cock, A; Degheele, D

    1991-01-01

    Treatment with buprofezin at the beginning of the third instar of Trialeurodes vaporariorum results in death of the larvae at the time of moulting. Electron microscopic observations, after treatment of the larvae with 20 mg a.i./l buprofezin, does not reveal any difference in the ultrastructural profile before apolysis, however formation of a normal lamellate procuticle is disturbed. The pharate procuticle is amorphous, varying in thickness and the mean thickness is greatly reduced. The subcuticle is interrupted several times at locations corresponding with the thinnest places of the pharate cuticle. Epidermal cells contain unusual structures such as myelin figures and hypertrophied mitochondria indicating that buprofezin may have an additional toxic effect on epidermal cells.

  3. Honey Bee (Apis mellifera Queen Reproductive Potential Affects Queen Mandibular Gland Pheromone Composition and Worker Retinue Response.

    Directory of Open Access Journals (Sweden)

    Juliana Rangel

    Full Text Available Reproductive division of labor is one of the defining traits of honey bees (Apis mellifera, with non-reproductive tasks being performed by workers while a single queen normally monopolizes reproduction. The decentralized organization of a honey bee colony is maintained in large part by a bouquet of queen-produced pheromones, the distribution of which is facilitated by contact among workers throughout the hive. Previous studies have shown that the developmental fate of honey bee queens is highly plastic, with queens raised from younger worker larvae exhibiting higher measures of reproductive potential compared to queens raised from older worker larvae. We investigated differences in the chemical composition of the mandibular glands and attractiveness to workers of "high-quality" queens (i.e., raised from first instar worker larvae; more queen-like and "low-quality" queens (i.e., raised from third instar worker larvae; more worker-like. We characterized the chemical profiles of the mandibular glands of high-quality queens and low-quality queens using GC-MS and used the worker retinue response as a measure of the attractiveness to workers of high-quality queens vs. low-quality queens. We found that queen quality affected the chemical profiles of mandibular gland contents differently across years, showing significant differences in the production of the queen mandibular pheromone ("QMP" components HVA and 9-HDA in 2010, but no significant differences of any glandular compound in 2012. We also found that workers were significantly more attracted to high-quality queens than to low-quality queens in 2012, possibly because of increased attractiveness of their mandibular gland chemical profiles. Our results indicate that the age at which honey bee larvae enter the "queen-specific" developmental pathway influences the chemical composition of queen mandibular glands and worker behavior. However, these changes are not consistent across years, suggesting

  4. The ectopic posterior pituitary gland

    African Journals Online (AJOL)

    2013-11-04

    Nov 4, 2013 ... crinology with short stature, delayed bone age and biochemical features suggestive of hypo pituitarism. Magnetic resonance imaging of the brain demonstrated a flattened anterior pituitary gland within the sella, associated with absence of the infundibular stalk and an ectopic posterior pituitary gland (Fig.

  5. Flexible and wearable electronic silk fabrics for human physiological monitoring

    Science.gov (United States)

    Mao, Cuiping; Zhang, Huihui; Lu, Zhisong

    2017-09-01

    The development of textile-based devices for human physiological monitoring has attracted tremendous interest in recent years. However, flexible physiological sensing elements based on silk fabrics have not been realized. In this paper, ZnO nanorod arrays are grown in situ on reduced graphene oxide-coated silk fabrics via a facile electro-deposition method for the fabrication of silk-fabric-based mechanical sensing devices. The data show that well-aligned ZnO nanorods with hexagonal wurtzite crystalline structures are synthesized on the conductive silk fabric surface. After magnetron sputtering of gold electrodes, silk-fabric-based devices are produced and applied to detect periodic bending and twisting. Based on the electric signals, the deformation and release processes can be easily differentiated. Human arterial pulse and respiration can also be real-time monitored to calculate the pulse rate and respiration frequency, respectively. Throat vibrations during coughing and singing are detected to demonstrate the voice recognition capability. This work may not only help develop silk-fabric-based mechanical sensing elements for potential applications in clinical diagnosis, daily healthcare monitoring and voice recognition, but also provide a versatile method for fabricating textile-based flexible electronic devices.

  6. Compliant threads maximize spider silk connection strength and toughness

    Science.gov (United States)

    Meyer, Avery; Pugno, Nicola M.; Cranford, Steven W.

    2014-01-01

    Millions of years of evolution have adapted spider webs to achieve a range of functionalities, including the well-known capture of prey, with efficient use of material. One feature that has escaped extensive investigation is the silk-on-silk connection joints within spider webs, particularly from a structural mechanics perspective. We report a joint theoretical and computational analysis of an idealized silk-on-silk fibre junction. By modifying the theory of multiple peeling, we quantitatively compare the performance of the system while systematically increasing the rigidity of the anchor thread, by both scaling the stress–strain response and the introduction of an applied pre-strain. The results of our study indicate that compliance is a virtue—the more extensible the anchorage, the tougher and stronger the connection becomes. In consideration of the theoretical model, in comparison with rigid substrates, a compliant anchorage enormously increases the effective adhesion strength (work required to detach), independent of the adhered thread itself, attributed to a nonlinear alignment between thread and anchor (contact peeling angle). The results can direct novel engineering design principles to achieve possible load transfer from compliant fibre-to-fibre anchorages, be they silk-on-silk or another, as-yet undeveloped, system. PMID:25008083

  7. Transmission Electron Microscopy of Bombyx Mori Silk Fibers

    Science.gov (United States)

    Shen, Y.; Martin, D. C.

    1997-03-01

    The microstructure of B. Mori silk fibers before and after degumming was examined by TEM, selected area electron diffraction (SAED), WAXS and low voltage SEM. SEM micrographs of the neat cocoon revealed a network of pairs of twisting filaments. After degumming, there were only individual filaments showing a surface texture consistent with an oriented fibrillar structure in the fiber interior. WAXS patterns confirmed the oriented beta-sheet crystal structure common to silkworm and spider silks. Low dose SAED results were fully consistent with the WAXS data, and revealed that the crystallographic texture did not vary significantly across the fiber diameter. TEM observations of microtomed fiber cross sections indicated a somewhat irregular shape, and also revealed a 0.5-2 micron sericin coating which was removed by the degumming process. TEM observations of the degummed silk fiber showed banded features with a characteristic spacing of nominally 600 nm along the fiber axis. These bands were oriented in a roughly parabolic or V-shape pointing along one axis within a given fiber. We hypothesize that this orientation is induced by the extrusion during the spinning process. Equatorial DF images revealed that axial and lateral sizes of the β-sheet crystallites in silk fibroin ranged from 20 to 170 nm and from 1 to 24 nm, respectively. Crazes developed in the degummed silk fiber parallel to the fiber direction. The formation of these crazes suggests that there are significant lateral interactions between fibrils in silk fibers.

  8. Engagement and contestation: The entangled imagery of the Silk Road

    Directory of Open Access Journals (Sweden)

    Timur Dadabaev

    2018-03-01

    Full Text Available There is considerable debate over how and in what form Central Asian (CA states should conduct relations among each other and with other post-Soviet states. The notion of the “Silk Road” has become one of the symbols of extended economic and political cooperation. Notably, however, Japan (Silk Road Diplomacy, 1996–1999, China (One Belt, One Road [OBOR] or the Belt and Road initiative [BRI] and South Korea (Silk Road Strategy, 2011 have used the rhetoric of reviving the Silk Road to imply closer engagement with the CA region but with different connotations. This paper focuses on the formation of this discourse of engagement with the CA region through the notion of the Silk Road in China, South Korea and Japan and raises the following questions: What are the approaches that facilitate the most effective ways of engaging CA states under this “Silk Road” rhetoric? What are the principles that have detrimental effects on the successes and failures of the engagement of China, Japan and South Korea? The primary objective of this paper is to address these questions and to stimulate debate among both academics and policy makers on the formats of engagement and cooperation in Eurasia.

  9. Development and Evaluation of Isoniazid Loaded Silk Fibroin Microsphere

    Directory of Open Access Journals (Sweden)

    Narinder Singh

    Full Text Available Aim: Current experimental investigation is dedicated to prepare microspheres with small size and good sphericity by Phase Separation method using Isoniazid (INH as model drug. Silk fibroin has unique intrinsic qualities like biodegradability, biocompatibility or release properties and their tunable drug loading capacity. The delivery loading proficiency of the drug molecules in silk spheres be contingent on their charge, and hydrophobicity or subsequent in altered drug release profiles. Methods: In the present work Isoniazid loaded silk fibroin microsphere was prepared by using phase separation method. Microsphere was evaluated for Ultraviolet-visible spectroscopy, Fourier Transform infrared spectroscopy, Entrapment efficiency, Scanning electron microscopy Studies. Results: Scanning electron microscopy studies revealed that Isoniazid Loaded Silk Fibroin Microspheres were spherical. Entrapment Efficiency of Isoniazid loaded Microspheres of different Formulation from F1 to F5 was in range of 53 to 68 %. F3 showed 68.47 % entrapment Efficiency and the optimized formulation drug release was 93.56 % at 24 hours. Conclusion: Experimental report disclosed a new aqueous based formulation method for silk spheres with controllable shape or size and sphere. Isoniazid loaded silk microspheres may act as ideal nano formulation with elaborated studies.

  10. Recombinant spider silk genetically functionalized with affinity domains.

    Science.gov (United States)

    Jansson, Ronnie; Thatikonda, Naresh; Lindberg, Diana; Rising, Anna; Johansson, Jan; Nygren, Per-Åke; Hedhammar, My

    2014-05-12

    Functionalization of biocompatible materials for presentation of active protein domains is an area of growing interest. Herein, we describe a strategy for functionalization of recombinant spider silk via gene fusion to affinity domains of broad biotechnological use. Four affinity domains of different origin and structure; the IgG-binding domains Z and C2, the albumin-binding domain ABD, and the biotin-binding domain M4, were all successfully produced as soluble silk fusion proteins under nondenaturing purification conditions. Silk films and fibers produced from the fusion proteins were demonstrated to be chemically and thermally stable. Still, the bioactive domains are concluded to be folded and accessible, since their respective targets could be selectively captured from complex samples, including rabbit serum and human plasma. Interestingly, materials produced from mixtures of two different silk fusion proteins displayed combined binding properties, suggesting that tailor-made materials with desired stoichiometry and surface distributions of several binding domains can be produced. Further, use of the IgG binding ability as a general mean for presentation of desired biomolecules could be demonstrated for a human vascular endothelial growth factor (hVEGF) model system, via a first capture of anti-VEGF IgG to silk containing the Z-domain, followed by incubation with hVEGF. Taken together, this study demonstrates the potential of recombinant silk, genetically functionalized with affinity domains, for construction of biomaterials capable of presentation of almost any desired biomolecule.

  11. Determination of Na, Mn and Cu in cocoon, raw silk and degummed silk by nondestructive activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Maki, Y; Ishiguro, Y [Industrial Research Inst. of Kanagawa Prefecture, Yokohama (Japan)

    1976-01-01

    The sodium, manganese and copper contained in cocoons, raw silk and degummed silk thread were determined by the nondestructive activation analysis. After each sample was irradiated with the thermal neutron flux of 5 x 10/sup 11/n/cm/sup 2/.sec, its ..gamma..-ray spectrum was measured with a NaI(Tl) detector. With the photoelectric peaks at 511 keV (/sup 64/Cu), 1368 keV (/sup 24/Na) and 847 keV (/sup 56/Mn), each element was quantitatively determined and its content was obtained. The measurement of the ..gamma..-ray spectra of samples with a Ge (Li) detector proved the presence of An, Sb, Fe, Zn, Cr, Sc, Co, etc. Large amounts of Na and Cu were detected in the sericin portion of cocoons, and the adhesion of Cu from a reeling-off machine to raw silk was also observed during the process of degumming cocoons to make raw silk.

  12. Electricity from the Silk Cocoon Membrane

    Science.gov (United States)

    Tulachan, Brindan; Meena, Sunil Kumar; Rai, Ratan Kumar; Mallick, Chandrakant; Kusurkar, Tejas Sanjeev; Teotia, Arun Kumar; Sethy, Niroj Kumar; Bhargava, Kalpana; Bhattacharya, Shantanu; Kumar, Ashok; Sharma, Raj Kishore; Sinha, Neeraj; Singh, Sushil Kumar; Das, Mainak

    2014-01-01

    Silk cocoon membrane (SCM) is an insect engineered structure. We studied the electrical properties of mulberry (Bombyx mori) and non-mulberry (Tussar, Antheraea mylitta) SCM. When dry, SCM behaves like an insulator. On absorbing moisture, it generates electrical current, which is modulated by temperature. The current flowing across the SCM is possibly ionic and protonic in nature. We exploited the electrical properties of SCM to develop simple energy harvesting devices, which could operate low power electronic systems. Based on our findings, we propose that the temperature and humidity dependent electrical properties of the SCM could find applications in battery technology, bio-sensor, humidity sensor, steam engines and waste heat management. PMID:24961354

  13. Silla Art and the Silk Road

    Directory of Open Access Journals (Sweden)

    Kwangshik Choe

    2014-02-01

    Full Text Available Western and Indian features found in Silla art, whether they came from the Western border regions of China or through a connection with China, it is recognized that there was both a direct and indirect a relationship between Silla, the West, and India. Many scholars have been interested in these aspects, conducting various studies as these factors played a large part in defining the origin of ancient culture and the process of harmonization between cultures. Through the Silk Road scholars are able to identify how Western cultures and civilizations were introduced to the Silla Dynasty. As the Korean peninsula has been a nexus for exchange between the East and the West, this paper aims to understand the meaning of the “Silk Road” and examines the actual state of cultural exchange at this historical site. Through artifacts excavated from Hwangnamdae-ch’ong (especially glass products, it has been determined that the Western and Western bordering countries of China culturally influenced the art of Silla. They also clearly prove that Buddhist sculptures from India and the Western bordering countries of China had a great impact on Silla art as well. Through these findings, it can be confirmed that from ancient times the influence of many cultures including China, the West, and the Western bordering countries of China had an impact on Korean culture. Particularly, Indian Buddhism which flowed into China and the Korea peninsula participated in the development of Silla culture and also played a significant role in the formation of traditional Korean culture.

  14. The Potential of Silk and Silk-Like Proteins as Natural Mucoadhesive Biopolymers for Controlled Drug Delivery.

    Science.gov (United States)

    Brooks, Amanda E

    2015-01-01

    Drug delivery across mucus membranes is a particularly effective route of administration due to the large surface area. However, the unique environment present at the mucosa necessitates altered drug formulations designed to (1) deliver sensitive biologic molecules, (2) promote intimate contact between the mucosa and the drug, and (3) prolong the drug's local residence time. Thus, the pharmaceutical industry has an interest in drug delivery systems formulated around the use of mucoadhesive polymers. Mucoadhesive polymers, both synthetic and biological, have a history of use in local drug delivery. Prominently featured in the literature are chitosan, alginate, and cellulose derivatives. More recently, silk and silk-like derivatives have been explored for their potential as mucoadhesive polymers. Both silkworms and spiders produce sticky silk-like glue substances, sericin and aggregate silk respectively, that may prove an effective, natural matrix for drug delivery to the mucosa. This mini review will explore the potential of silk and silk-like derivatives as a biocompatible mucoadhesive polymer matrix for local controlled drug delivery.

  15. The potential of silk and silk-like proteins as natural mucoadhesive biopolymers for controlled drug delivery

    Directory of Open Access Journals (Sweden)

    Amanda E Brooks

    2015-11-01

    Full Text Available Drug delivery across mucus membranes is a particularly effective route of administration due to the large surface area. However, the unique environment present at the mucosa necessitates altered drug formulations designed to (1 deliver sensitive biologic molecules, (2 promote intimate contact between the mucosa and the drug, and (3 prolong the drug’s local residence time. Thus, the pharmaceutical industry has an interest in drug delivery systems formulated around the use of mucoadhesive polymers. Mucoadhesive polymers, both synthetic and biological, have a history of use in local drug delivery. Prominently featured in the literature are chitosan, alginate, and cellulose derivatives. More recently, silk and silk-like derivatives have been explored for their potential as mucoadhesive polymers. Both silkworms and spiders produce sticky silk-like glue substances, sericin and aggregate silk respectively, that may prove an effective, natural matrix for drug delivery to the mucosa. This mini review will explore the potential of silk and silk-like derivatives as a biocompatible mucoadhesive polymer matrix for local controlled drug delivery.

  16. Pituitary gland tumors; Hypophysentumoren

    Energy Technology Data Exchange (ETDEWEB)

    Jesser, J.; Schlamp, K.; Bendszus, M. [Radiologische Klinik, Universitaetsklinikum Heidelberg, Abteilung fuer Neuroradiologie, Heidelberg (Germany)

    2014-10-15

    This article gives an overview of the most common tumors of the pituitary gland and the differential diagnostics with special emphasis on radiological diagnostic criteria. A selective search of the literature in PubMed was carried out. Pituitary adenomas constitute 10-15 % of all intracranial tumors and are the most common tumors of the sellar region. Tumors smaller than 1 cm in diameter are called microadenomas while those larger than 1 cm in diameter are called macroadenomas. Approximately 65 % of pituitary gland adenomas secrete hormones whereby approximately 50 % secrete prolactin, 10 % secrete growth hormone (somatotropin) and 6 % secrete corticotropin. Other tumors located in the sella turcica can also cause endocrinological symptoms, such as an oversecretion of pituitary hormone or pituitary insufficiency by impinging on the pituitary gland or its stalk. When tumors spread into the space cranial to the sella turcica, they can impinge on the optic chiasm and cause visual disorders. A common differential diagnosis of a sellar tumor is a craniopharyngeoma. In children up to 10 % of all intracranial tumors are craniopharyngeomas. Other differential diagnoses for sellar tumors are metastases, meningiomas, epidermoids and in rare cases astrocytomas, germinomas or Rathke cleft cysts As these tumors are located in an anatomically complex region of the skull base and are often very small, a highly focused imaging protocol is required. The currently favored modality is magnetic resonance imaging (MRI) with the administration of a contrast agent. The sellar region should be mapped in thin slices. In cases of suspected microadenoma the imaging protocol should also contain a sequence with dynamic contrast administration in order to assess the specific enhancement characteristics of the tumor and the pituitary gland. (orig.) [German] Diese Arbeit ist eine Uebersicht ueber die haeufigsten Hypophysentumoren und deren Differenzialdiagnosen mit Augenmerk auf die

  17. Chapter 13. Adrenal glands

    International Nuclear Information System (INIS)

    Roux, H.; Paulin, R.

    1975-01-01

    The condition of isotopic methods to the functional and morphological exploration of the adrenal glands is shown, with emphasis on the fact that althought the cortico-adrenal responds to these methods the same does not apply to the medullo-adrenal, which expresses its morphological changes by producing deformations on the cortical image. Funtional tests, mainly directed at the cortico-adrenal, are described first: study of exchangeable sodium and potassium; determination of the plasma concentration and metabolic clearance of some steroid hormones (cortisol, corticosterone, aldosterone); evaluation of the renin activity. These tests are based on competitive analysis and radioimmunological methods. Morphological tests are examined next. Adrenal scintigraphy uses a simple technique (intraveinous administration of 131 I 19-iodocholesterol with no special preliminary preparation) which gives good images and is only limited now by the need to avoid over exposure of the gonads to ionising radiations [fr

  18. Cryopreservation of Parathyroid Glands

    Directory of Open Access Journals (Sweden)

    Marlon A. Guerrero

    2010-01-01

    Full Text Available The risk of permanent hypoparathyroidism following thyroid and parathyroid surgery is around 1% in the hands of experienced endocrine surgeons. Although this complication is rare, rendering a patient permanently aparathyroid has significant consequences on the health and quality of life of the patient. Immediate autotransplantation of parathyroid glands that are injured or unintentionally removed offers the best possibility of graft viability and functionality. However, since the majority of cases of hypoparathyroidism are transient, immediate autotransplantation can complicate postoperative surveillance in certain patients, especially those with primary hyperparathyroidism. Cryopreservation of parathyroid tissue is an alternate technique that was developed to treat patients with permanent hypoparathyroidism. This method allows for parathyroid tissue to be stored and then autotransplanted in a delayed fashion once permanent hypoparathyroidism is confirmed. This article provides a contemporary review on cryopreservation of parathyroid tissue and its current role in thyroid and parathyroid surgery.

  19. Irradiation effects on the duration of intermolt in nymphs of the fourth instar of Panstrongylus megistus Burmeister, 1835 (Hemiptera: Reduviidae)

    International Nuclear Information System (INIS)

    Barros Falcao, P.H. de.

    1987-01-01

    The duration of intermolt, in nymphs of the fourth instar, of P. megistus, submitted to irradiation with Cobalt 60, 24 hs after the blood meal is studied. The insects were divided in four groups of 40 and were irradiated with doses of 10, 20, 40 and 80 Gray, respectively. (M.A.C.) [pt

  20. Description and key to the fifth-instars of some Cicadas (Hemiptera: Cicadidae) associated with coffee plants in Brazil.

    Science.gov (United States)

    Maccagnan, D H B; Martinelli, N M

    2011-01-01

    Fifth-instars of the cicada species Dorisiana drewseni (Stål), Dorisiana viridis (Olivier), Fidicina mannifera (Fabricius), Fidicinoides pronoe (Walker) and Carineta fasciculata (Germar) are described and illustrated. Moreover, a key to the nymphs of these species along with Quesada gigas (Olivier) is also provided.

  1. Description of Larval Instars To Fill a Gap in Forensic Entomology: The Larvae of Paralucilia pseudolyrcea (Diptera: Calliphoridae).

    Science.gov (United States)

    Da Silva, S M; Vairo, K P; Moura, M O

    2018-05-04

    A fundamental assumption of forensic entomology for estimating the postmortem interval is that insect species are accurately identified, which depends on diagnostic morphological characters. Larvae of the blow fly Paralucilia pseudolyrcea (Mello, 1969) (Diptera: Calliphoridae) were sampled from four corpses in the state of Paraná, Brazil, but despite the forensic importance of this species, morphological data for the identification of its larval instars are lacking, limiting its usefulness in such cases. Thus, the main goal of this study was to describe the larval instars of P. pseudolyrcea. The material was obtained from a colony established by larvae collected from a corpse of a murder case. Overall, the distribution of spines is a key character for identifying this species in the first, second and third instars. Other characteristics, such as the presence of an accessory oral sclerite, the small cirri, the number of lobes of the anterior spiracle and the morphology of posterior spiracles, separates P. pseudolyrcea from other necrophagous blow flies. The detailed morphological description provided here facilitates the identification of larval instars of P. pseudolyrcea and their differentiation from those of other calliphorid species.

  2. Application of a frequency distribution method for determining instars of the beet armyworm (Lepidoptera: Noctuidae) from widths of cast head capsules

    Science.gov (United States)

    Y. Chen; S. J. Seybold

    2013-01-01

    Instar determination of field-collected insect larvae has generally been based on the analysis of head capsule width frequency distributions or bivariate plotting, but few studies have tested the validity of such methods. We used head capsules from exuviae of known instars of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae),...

  3. Descrição da larva de último instar e pupa de Epacroplon cruciatum (Aurivillius (Coleoptera, Cerambycidae, Cerambycinae e notas biológica

    Directory of Open Access Journals (Sweden)

    Juares Fuhrmann

    2012-03-01

    Full Text Available Descrição da larva de último instar e pupa de Epacroplon cruciatum (Aurivillius (Coleoptera, Cerambycidae, Cerambycinae e notas biológicas. Último instar larval e pupa do Hexoplonini sul-americano Epacroplon cruciatum (Aurivillius, 1899 são descritos, ilustrados e disponibilizadas notas biológicas.

  4. Natural Silk as a Photonics Component: a Study on Its Light Guiding and Nonlinear Optical Properties

    OpenAIRE

    Kujala, Sami; Mannila, Anna; Karvonen, Lasse; Kieu, Khanh; Sun, Zhipei

    2016-01-01

    Silk fibers are expected to become a pathway to biocompatible and bioresorbable waveguides, which could be used to deliver localized optical power for various applications, e.g., optical therapy or imaging inside living tissue. Here, for the first time, the linear and nonlinear optical properties of natural silk fibers have been studied. The waveguiding properties of silk fibroin of largely unprocessed Bombyx mori silkworm silk are assessed using two complementary methods, and found to be on ...

  5. Traveling the Silk Road: A Measurement of a Large Anonymous Online Marketplace

    Science.gov (United States)

    2012-11-28

    Silk Road, an anonymous, international online marketplace that operates as a Tor hidden service and uses Bitcoin as its exchange currency. We gather...analysis of Silk Road, an anonymous, international on- line marketplace that operates as a Tor hidden service and uses Bitcoin as its exchange currency. We...anonymity, Silk Road needs to also preserve payment anonymity. To that effect, Silk Road only supports Bitcoin (BTC, [30]) as a trading currency

  6. Multifunctional surface modification of silk fabric via graphene oxide repeatedly coating and chemical reduction method

    Science.gov (United States)

    Cao, Jiliang; Wang, Chaoxia

    2017-05-01

    Multifunctional silk fabrics with electrical conductive, anti-ultraviolet and water repellent were successfully prepared by surface modification with graphene oxide (GO). The yellow-brown GO deposited on the surface of silk fabric was converted into graphitic black reduced graphene (RGO) by sodium hydrosulfite. The surface properties of silk fabrics were changed by repeatedly RGO coating process, which have been proved by SEM and XPS. The SEM results showed that the RGO sheets were successive form a continuously thin film on the surface of silk fabrics, and the deposition of GO or RGO also can be proved by XPS. The electrical conductivity was tested by electrical surface resistance value of the silk fabric, the surface resistance decreased with increasing of RGO surface modification times, and a low surface resistance value reached to 3.24 KΩ cm-1 after 9 times of modification, indicating the silk obtained excellent conductivity. The UPF value of one time GO modification silk fabric (silk-1RGO) was enhanced significantly to 24.45 in comparison to 10.40 of original silk. The contact angle of RGO coating silk samples was all above of 120°. The durability of RGO coated silk fabrics was tested by laundering. The electrical surface resistance of silk-4RGO (65.74 KΩ cm-1), silk-6RGO (15.54 KΩ cm-1) and silk-8RGO (3.86 KΩ cm-1) fabrics was up to 86.82, 22.30 and 6.57 KΩ cm-1 after 10 times of standard washing, respectively. The UPF value, contact angle and color differences of RGO modified silk fabric slightly changed before and after 10 times of standard washing. Therefore, the washing fastness of electric conduction, anti-ultraviolet and water repellent multifunctional silk fabrics was excellent.

  7. Solubilization of spider silk proteins and its structural analysis using Fourier transform infrared spectroscopy

    Science.gov (United States)

    Osbin, K.; Jayan, Manuel; Bhadrakumari, S.; Predeep, P.

    2017-06-01

    This study investigates the presence of various amide bands present in different spider silk species, which provides extraordinary physical properties. Three different spider silks were collected from Western Ghats region. The collected spider silks samples belonging to the spider Heteropoda venatoria (species 1), Hersilia savignyi (species 2) and Pholcus phalangioides (species 3). Fourier transform infrared (FTIR) spectra reveals the protein peaks in the amide I, II, and III regions in all the three types of spider silk species.

  8. Synthetic Spider Silk Production on a Laboratory Scale

    Science.gov (United States)

    Hsia, Yang; Gnesa, Eric; Pacheco, Ryan; Kohler, Kristin; Jeffery, Felicia; Vierra, Craig

    2012-01-01

    As society progresses and resources become scarcer, it is becoming increasingly important to cultivate new technologies that engineer next generation biomaterials with high performance properties. The development of these new structural materials must be rapid, cost-efficient and involve processing methodologies and products that are environmentally friendly and sustainable. Spiders spin a multitude of different fiber types with diverse mechanical properties, offering a rich source of next generation engineering materials for biomimicry that rival the best manmade and natural materials. Since the collection of large quantities of natural spider silk is impractical, synthetic silk production has the ability to provide scientists with access to an unlimited supply of threads. Therefore, if the spinning process can be streamlined and perfected, artificial spider fibers have the potential use for a broad range of applications ranging from body armor, surgical sutures, ropes and cables, tires, strings for musical instruments, and composites for aviation and aerospace technology. In order to advance the synthetic silk production process and to yield fibers that display low variance in their material properties from spin to spin, we developed a wet-spinning protocol that integrates expression of recombinant spider silk proteins in bacteria, purification and concentration of the proteins, followed by fiber extrusion and a mechanical post-spin treatment. This is the first visual representation that reveals a step-by-step process to spin and analyze artificial silk fibers on a laboratory scale. It also provides details to minimize the introduction of variability among fibers spun from the same spinning dope. Collectively, these methods will propel the process of artificial silk production, leading to higher quality fibers that surpass natural spider silks. PMID:22847722

  9. Molecular mechanics of silk nanostructures under varied mechanical loading.

    Science.gov (United States)

    Bratzel, Graham; Buehler, Markus J

    2012-06-01

    Spider dragline silk is a self-assembling tunable protein composite fiber that rivals many engineering fibers in tensile strength, extensibility, and toughness, making it one of the most versatile biocompatible materials and most inviting for synthetic mimicry. While experimental studies have shown that the peptide sequence and molecular structure of silk have a direct influence on the stiffness, toughness, and failure strength of silk, few molecular-level analyses of the nanostructure of silk assemblies, in particular, under variations of genetic sequences have been reported. In this study, atomistic-level structures of wildtype as well as modified MaSp1 protein from the Nephila clavipes spider dragline silk sequences, obtained using an in silico approach based on replica exchange molecular dynamics and explicit water molecular dynamics, are subjected to simulated nanomechanical testing using different force-control loading conditions including stretch, pull-out, and peel. The authors have explored the effects of the poly-alanine length of the N. clavipes MaSp1 peptide sequence and identify differences in nanomechanical loading conditions on the behavior of a unit cell of 15 strands with 840-990 total residues used to represent a cross-linking β-sheet crystal node in the network within a fibril of the dragline silk thread. The specific loading condition used, representing concepts derived from the protein network connectivity at larger scales, have a significant effect on the mechanical behavior. Our analysis incorporates stretching, pull-out, and peel testing to connect biochemical features to mechanical behavior. The method used in this study could find broad applications in de novo design of silk-like tunable materials for an array of applications. Copyright © 2011 Wiley Periodicals, Inc.

  10. Correlation between fibroin amino acid sequence and physical silk properties.

    Science.gov (United States)

    Fedic, Robert; Zurovec, Michal; Sehnal, Frantisek

    2003-09-12

    The fiber properties of lepidopteran silk depend on the amino acid repeats that interact during H-fibroin polymerization. The aim of our research was to relate repeat composition to insect biology and fiber strength. Representative regions of the H-fibroin genes were sequenced and analyzed in three pyralid species: wax moth (Galleria mellonella), European flour moth (Ephestia kuehniella), and Indian meal moth (Plodia interpunctella). The amino acid repeats are species-specific, evidently a diversification of an ancestral region of 43 residues, and include three types of regularly dispersed motifs: modifications of GSSAASAA sequence, stretches of tripeptides GXZ where X and Z represent bulky residues, and sequences similar to PVIVIEE. No concatenations of GX dipeptide or alanine, which are typical for Bombyx silkworms and Antheraea silk moths, respectively, were found. Despite different repeat structure, the silks of G. mellonella and E. kuehniella exhibit similar tensile strength as the Bombyx and Antheraea silks. We suggest that in these latter two species, variations in the repeat length obstruct repeat alignment, but sufficiently long stretches of iterated residues get superposed to interact. In the pyralid H-fibroins, interactions of the widely separated and diverse motifs depend on the precision of repeat matching; silk is strong in G. mellonella and E. kuehniella, with 2-3 types of long homogeneous repeats, and nearly 10 times weaker in P. interpunctella, with seven types of shorter erratic repeats. The high proportion of large amino acids in the H-fibroin of pyralids has probably evolved in connection with the spinning habit of caterpillars that live in protective silk tubes and spin continuously, enlarging the tubes on one end and partly devouring the other one. The silk serves as a depot of energetically rich and essential amino acids that may be scarce in the diet.

  11. 'Surfing the Silk Road': a study of users' experiences.

    Science.gov (United States)

    Van Hout, Marie Claire; Bingham, Tim

    2013-11-01

    The online drug marketplace called 'Silk Road' has operated anonymously on the 'Deep Web' since 2011. It is accessible through computer encrypting software (Tor) and is supported by online transactions using peer to peer anonymous and untraceable crypto-currency (Bit Coins). The study aimed to describe user motives and realities of accessing, navigating and purchasing on the 'Silk Road' marketplace. Systematic online observations, monitoring of discussion threads on the site during four months of fieldwork and analysis of anonymous online interviews (n=20) with a convenience sample of adult 'Silk Road' users was conducted. The majority of participants were male, in professional employment or in tertiary education. Drug trajectories ranged from 18 months to 25 years, with favourite drugs including MDMA, 2C-B, mephedrone, nitrous oxide, ketamine, cannabis and cocaine. Few reported prior experience of online drug sourcing. Reasons for utilizing 'Silk Road' included curiosity, concerns for street drug quality and personal safety, variety of products, anonymous transactioning, and ease of product delivery. Vendor selection appeared to be based on trust, speed of transaction, stealth modes and quality of product. Forums on the site provided user advice, trip reports, product and transaction reviews. Some users reported solitary drug use for psychonautic and introspective purposes. A minority reported customs seizures, and in general a displacement away from traditional drug sourcing (street and closed markets) was described. Several reported intentions to commence vending on the site. The study provides an insight into 'Silk Road' purchasing motives and processes, the interplay between traditional and 'Silk Road' drug markets, the 'Silk Road' online community and its communication networks. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. [Immunoendocrine associations in adrenal glands].

    Science.gov (United States)

    Sterzl, I; Hrdá, P

    2010-12-01

    Immune and endocrine systems are basic regulatory mechanisms of organism and, including the nervous system, maintain the organism's homeostasis. The main immune system representatives are mononuclear cells, T- and B-cells and their products, in the endocrine system the main representatives are cells of the glands with inner secretion and their products. One of the most important glands for maintaining homeostasis are adrenal glands. It has been proven that either cells of the immune system, either endocrine cells can, although in trace amounts, produce mutually mediators of both systems (hormones, cytokines). Disorders in one system can lead to pathological symptoms in the other system. Also here represent adrenals an important model.

  13. [Engineered spider silk: the intelligent biomaterial of the future. Part I].

    Science.gov (United States)

    Florczak, Anna; Piekoś, Konrad; Kaźmierska, Katarzyna; Mackiewicz, Andrzej; Dams-Kozłowska, Hanna

    2011-06-17

    The unique properties of spider silk such as strength, extensibility, toughness, biocompatibility and biodegradability are the reasons for the recent development in silk biomaterial technology. For a long time scientific progress was impeded by limited access to spider silk. However, the development of the molecular biology strategy was a breaking point in synthetic spider silk protein design. The sequences of engineered spider silk are based on the consensus motives of the corresponding natural equivalents. Moreover, the engineered silk proteins may be modified in order to gain a new function. The strategy of the hybrid proteins constructed on the DNA level combines the sequence of engineered silk, which is responsible for the biomaterial structure, with the sequence of polypeptide which allows functionalization of the silk biomaterial. The functional domains may comprise receptor binding sites, enzymes, metal or sugar binding sites and others. Currently, advanced research is being conducted, which on the one hand focuses on establishing the particular silk structure and understanding the process of silk thread formation in nature. On the other hand, there are attempts to improve methods of engineered spider silk protein production. Due to acquired knowledge and recent progress in synthetic protein technology, the engineered silk will turn into intelligent biomaterial of the future, while its industrial production scale will trigger a biotechnological revolution.

  14. Effects of Japanese beetle (Coleoptera: Scarabaeidae) and silk clipping in field corn.

    Science.gov (United States)

    Steckel, Sandy; Stewart, S D; Tindall, K V

    2013-10-01

    Japanese beetle (Popillia japonica Newman) is an emerging silk-feeding insect found in fields in the lower Corn Belt and Midsouthern United States. Studies were conducted in 2010 and 2011 to evaluate how silk clipping in corn affects pollination and yield parameters. Manually clipping silks once daily had modest effects on yield parameters. Sustained clipping by either manually clipping silks three times per day or by caging Japanese beetles onto ears affected total kernel weight if it occurred during early silking (R1 growth stage). Manually clipping silks three times per day for the first 5 d of silking affected the number of kernels per ear, total kernel weight, and the weight of individual kernels. Caged beetles fed on silks and, depending on the number of beetles caged per ear, reduced the number of kernels per ear. Caging eight beetles per ear significantly reduced total kernel weight compared with noninfested ears. Drought stress before anthesis appeared to magnify the impact of silk clipping by Japanese beetles. There was evidence of some compensation for reduced pollination by increasing the size of pollinated kernels within the ear. Our results showed that it requires sustained silk clipping during the first week of silking to have substantial impacts on pollination and yield parameters, at least under good growing conditions. Some states recommend treating for Japanese beetle when three Japanese beetles per ear are found, silks are clipped to < 13 mm, and pollination is < 50% complete, and that recommendation appears to be adequate.

  15. The inflammatory responses to silk films in vitro and in vivo

    NARCIS (Netherlands)

    Meinel, L.; Hofmann, S.; Karageorgiou, V.; Kirker-Head, C.; McCool, J.; Gronowicz, G.; Zichner, L.; Langer, R.; Vunjak-Novakovic, G.; Kaplan, D.L.

    2005-01-01

    Silks have a long history of biomedical use as sutures. Silk can be purified, chemically modified to attach RGD sequences and processed into highly porous scaffolds for tissue engineering. We report biocompatibility studies of silk films (with or without covalently bound RGD) that were seeded with

  16. Physical characterization of functionalized spider silk: electronic and sensing properties

    Directory of Open Access Journals (Sweden)

    Eden Steven, Jin Gyu Park, Anant Paravastu, Elsa Branco Lopes, James S Brooks, Ongi Englander, Theo Siegrist, Papatya Kaner and Rufina G Alamo

    2011-01-01

    Full Text Available This work explores functional, fundamental and applied aspects of naturally harvested spider silk fibers. Natural silk is a protein polymer where different amino acids control the physical properties of fibroin bundles, producing, for example, combinations of β-sheet (crystalline and amorphous (helical structural regions. This complexity presents opportunities for functional modification to obtain new types of material properties. Electrical conductivity is the starting point of this investigation, where the insulating nature of neat silk under ambient conditions is described first. Modification of the conductivity by humidity, exposure to polar solvents, iodine doping, pyrolization and deposition of a thin metallic film are explored next. The conductivity increases exponentially with relative humidity and/or solvent, whereas only an incremental increase occurs after iodine doping. In contrast, iodine doping, optimal at 70 °C, has a strong effect on the morphology of silk bundles (increasing their size, on the process of pyrolization (suppressing mass loss rates and on the resulting carbonized fiber structure (that becomes more robust against bending and strain. The effects of iodine doping and other functional parameters (vacuum and thin film coating motivated an investigation with magic angle spinning nuclear magnetic resonance (MAS-NMR to monitor doping-induced changes in the amino acid-protein backbone signature. MAS-NMR revealed a moderate effect of iodine on the helical and β-sheet structures, and a lesser effect of gold sputtering. The effects of iodine doping were further probed by Fourier transform infrared (FTIR spectroscopy, revealing a partial transformation of β-sheet-to-amorphous constituency. A model is proposed, based on the findings from the MAS-NMR and FTIR, which involves iodine-induced changes in the silk fibroin bundle environment that can account for the altered physical properties. Finally, proof

  17. Physical characterization of functionalized spider silk: electronic and sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Steven, Eden; Brooks, James S [Department of Physics and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac, Tallahassee, FL 32310 (United States); Park, Jin Gyu [FAMU-FSU Department of Industrial and Manufacturing Engineering, High-Performance Materials Institute, Florida State University, 2005 Levy Ave., Tallahassee, FL 32310 (United States); Paravastu, Anant; Siegrist, Theo; Kaner, Papatya; Alamo, Rufina G [FAMU-FSU Department of Chemical and Biomedical Engineering and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac, Tallahassee, FL 32310 (United States); Branco Lopes, Elsa [Departamento de Quimica, Instituto Tecnologico e Nuclear/CFMC-UL, P-2686-953 Sacavem (Portugal); Englander, Ongi, E-mail: esteven@magnet.fsu.edu [FAMU-FSU Department of Mechanical Engineering and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac, Tallahassee, Florida 32310 (United States)

    2011-10-15

    This work explores functional, fundamental and applied aspects of naturally harvested spider silk fibers. Natural silk is a protein polymer where different amino acids control the physical properties of fibroin bundles, producing, for example, combinations of {beta}-sheet (crystalline) and amorphous (helical) structural regions. This complexity presents opportunities for functional modification to obtain new types of material properties. Electrical conductivity is the starting point of this investigation, where the insulating nature of neat silk under ambient conditions is described first. Modification of the conductivity by humidity, exposure to polar solvents, iodine doping, pyrolization and deposition of a thin metallic film are explored next. The conductivity increases exponentially with relative humidity and/or solvent, whereas only an incremental increase occurs after iodine doping. In contrast, iodine doping, optimal at 70 deg. C, has a strong effect on the morphology of silk bundles (increasing their size), on the process of pyrolization (suppressing mass loss rates) and on the resulting carbonized fiber structure (that becomes more robust against bending and strain). The effects of iodine doping and other functional parameters (vacuum and thin film coating) motivated an investigation with magic angle spinning nuclear magnetic resonance (MAS-NMR) to monitor doping-induced changes in the amino acid-protein backbone signature. MAS-NMR revealed a moderate effect of iodine on the helical and {beta}-sheet structures, and a lesser effect of gold sputtering. The effects of iodine doping were further probed by Fourier transform infrared (FTIR) spectroscopy, revealing a partial transformation of {beta}-sheet-to-amorphous constituency. A model is proposed, based on the findings from the MAS-NMR and FTIR, which involves iodine-induced changes in the silk fibroin bundle environment that can account for the altered physical properties. Finally, proof

  18. Physical characterization of functionalized spider silk: electronic and sensing properties

    International Nuclear Information System (INIS)

    Steven, Eden; Brooks, James S; Park, Jin Gyu; Paravastu, Anant; Siegrist, Theo; Kaner, Papatya; Alamo, Rufina G; Branco Lopes, Elsa; Englander, Ongi

    2011-01-01

    This work explores functional, fundamental and applied aspects of naturally harvested spider silk fibers. Natural silk is a protein polymer where different amino acids control the physical properties of fibroin bundles, producing, for example, combinations of β-sheet (crystalline) and amorphous (helical) structural regions. This complexity presents opportunities for functional modification to obtain new types of material properties. Electrical conductivity is the starting point of this investigation, where the insulating nature of neat silk under ambient conditions is described first. Modification of the conductivity by humidity, exposure to polar solvents, iodine doping, pyrolization and deposition of a thin metallic film are explored next. The conductivity increases exponentially with relative humidity and/or solvent, whereas only an incremental increase occurs after iodine doping. In contrast, iodine doping, optimal at 70 deg. C, has a strong effect on the morphology of silk bundles (increasing their size), on the process of pyrolization (suppressing mass loss rates) and on the resulting carbonized fiber structure (that becomes more robust against bending and strain). The effects of iodine doping and other functional parameters (vacuum and thin film coating) motivated an investigation with magic angle spinning nuclear magnetic resonance (MAS-NMR) to monitor doping-induced changes in the amino acid-protein backbone signature. MAS-NMR revealed a moderate effect of iodine on the helical and β-sheet structures, and a lesser effect of gold sputtering. The effects of iodine doping were further probed by Fourier transform infrared (FTIR) spectroscopy, revealing a partial transformation of β-sheet-to-amorphous constituency. A model is proposed, based on the findings from the MAS-NMR and FTIR, which involves iodine-induced changes in the silk fibroin bundle environment that can account for the altered physical properties. Finally, proof-of-concept applications of

  19. Intrasellar Symptomatic Salivary Gland Rest

    Directory of Open Access Journals (Sweden)

    Chih-Hao Chen

    2007-05-01

    Full Text Available Ectopic salivary gland tissue in sellar turcica is frequently observed in microscopic examination at autopsy. This tissue is considered clinically silent. Only 2 symptomatic cases have been previously reported. Here we report a 28-year-old woman presenting with galactorrhea and hyperprolactinemia. Magnetic resonance imaging revealed a 6×5-mm nodule in the posterior aspect of the pituitary gland. This nodule showed isointensity on T1- and T2-weighted images and less enhancement on post-contrast T1-weighted images. Transsphenoidal exploration revealed a cystic lesion within the pituitary gland, which consisted of a grayish gelatinous content. The pathologic examination confirmed the diagnosis of salivary gland rest.

  20. Subchronic toxicity study of corn silk with rats.

    Science.gov (United States)

    Wang, Cuina; Zhang, Tiehua; Liu, Jun; Lu, Shuang; Zhang, Cheng; Wang, Erlei; Wang, Zuozhao; Zhang, Yan; Liu, Jingbo

    2011-09-01

    Corn silk is a traditional herbal medicine in China, which has been used in many parts of the world for the treatment of edema as well as for cystitis, gout, kidney stones, nephritis, prostatitis and similar ailments. However, there is little scientific evidence about its safety. As a part of its safety assessment, a subchronic toxicity was performed in this paper. The subchronic toxicity was investigated in male and female Wistar rats by dietary administration at concentrations of 0.5%, 2.0% and 8.0% (w/w) for 90 days. Overall health, body weight, food consumption, hematology, blood chemistry, organ weights, gross and microscopic appearance of tissues were compared between test and control groups. A number of significant differences were seen between groups, but none of them was considered to be adverse. Based on the present study, the no-observed-adverse-effect level (NOAEL) of corn silk is at least 8.0% which corresponds to a mean daily corn silk intake of approximately 9.354 and 10.308 g/day/kg body weight for males and females, respectively. The results obtained in the present study suggest that consumption of corn silk has no adverse effects and support the safety of corn silk for humans. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  1. Adsorption Properties of Lac Dyes on Wool, Silk, and Nylon

    Directory of Open Access Journals (Sweden)

    Bo Wei

    2013-01-01

    Full Text Available There has been growing interest in the dyeing of textiles with natural dyes. The research about the adsorption properties of natural dyes can help to understand their adsorption mechanism and to control their dyeing process. This study is concerned with the kinetics and isotherms of adsorption of lac dyes on wool, silk, and nylon fibers. It was found that the adsorption kinetics of lac dyes on the three fibers followed the pseudosecond-order kinetic model, and the adsorption rate of lac dyes was the fastest for silk and the slowest for wool. The activation energies for the adsorption process on wool, silk, and nylon were found to be 107.15, 87.85, and 45.31 kJ/mol, respectively. The adsorption of lac dyes on the three fibers followed the Langmuir mechanism, indicating that the electrostatic interactions between lac dyes and those fibers occurred. The saturation values for lac adsorption on the three fibers decreased in the order of wool > silk > nylon; the Langmuir affinity constant of lac adsorption on nylon was much higher than those on wool and silk.

  2. Biomaterials Derived from Silk-Tropoelastin Protein Systems

    Science.gov (United States)

    Hu, Xiao; Wang, Xiuli; Rnjak, Jelena; Weiss, Anthony S.; Kaplan, David L.

    2010-01-01

    A structural protein blend system based on silkworm silk fibroin and recombinant human tropoelastin is described. Silk fibroin, a semicrystalline fibrous protein with beta-sheet crystals provides mechanical strength and controllable biodegradation, while tropoelastin, a noncrystallizable elastic protein provides elasticity. Differential scanning calorimetry (DSC) and temperature modulated DSC (TMDSC) indicated that silk becomes miscible with tropoelastin at different blend ratios, without macrophase separation. Fourier transform infrared spectroscopy (FTIR) revealed secondary structural changes of the blend system (beta-sheet content) before and after methanol treatment. Atomic Force Microscopy (AFM) nano-indentation demonstrated that blending silk and tropoelastin at different ratios resulted in modification of mechanical features, with resilience from ~68% to ~97%, and elastic modulus between 2~9Mpa, depending on the ratio of the two polymers. Some of these values are close to those of native aortic elastin or elastin-like polypeptides. Significantly, during blending and drying silk-tropoelastin form micro- and nano-scale porous morphologies which promote human mesenchymal stem cell attachment and proliferation. These blends offer a new protein biomaterial system for cell support and tailored biomaterial properties to match mechanical needs. PMID:20674969

  3. The Effects of Silk Protein Solution on Quality of Mangosteen

    International Nuclear Information System (INIS)

    Phadvibulya, Valailak; Sudatis, Boonya; Panyarum, Kanyarat; Junsaithong, Mayuree; Kerdchoechuen, Orapin

    2011-06-01

    Full text: Sericin silk protein solution prepared from irradiated silk waste was applied as a wax coating on mangosteen fruits but was found not appropriate. Nonetheless, when the solution was sprayed onto fruits from the setting stage till maturity, it enhanced the fruit quality. Fruits showed a bigger stalk and greener, thicker and larger-angled calyx than untreated ones. They were edible after being kept at 25 C for 3 to 4 weeks. Fruits sprayed with the silk protein solution and untreated fruits were separately harvested and packed for export. A half of them were irradiated with gamma radiation for insect eradication and then kept at 10 C with 80 percents relative humidity. The unirradiated half was stored similarly. Results showed that rind color of irradiated fruits changed slower than unirradiated ones. However, silk protein solution spraying and irradiation did not affect fruit firmness and total soluble solids of mangosteen flesh. For sensory evaluation, it was found that sprayed and irradiated fruits showed no differences from the untreated ones in their physical properties, color, taste and odor. Fruits sprayed with the silk protein solution without irradiation had the longest shelf life of 6 weeks

  4. Extracted sericin from silk waste for film formation

    Directory of Open Access Journals (Sweden)

    Rungsinee Sothornvit

    2010-03-01

    Full Text Available Sericin is the second main component in cocoons, which are removed in the silk reeling process of the raw silk industry and in the silk waste degumming of the spun silk industry. The main amino acid of sericin, serine, exhibits a skin moisturing and antiwrinkle action, which is interesting to use for film formation in this study. The extraction conditions of sericin from two silk wastes, pieced cocoon and inferior knubbs were studied to find the optimum extraction conditions. Boiling water extraction was considered based on the response surface methodology (RSM in order to identify the important factors for the sericin extraction. The two factors considered were time and temperature. Both factors were needed to be independent parameters in the predicted equation in order to improve the model fit with R2 = 0.84. The components ofextracted sericin were 18.24% serine, 9.83% aspatate, and 5.51% glycine with a molecular weight of 132 kDa. Film formationfrom extracted sericin was carried out to find the optimum conditions. Extracted sericin could not form a stand-alonefilm. Therefore, polysaccharide polymers, such as glucomannan, were incorporated with glycerol to form a flexible film.Sericin-based films were characterized for its properties in terms of solubility and permeability before application. It wasfound that sericin-based films showed a film flexibility and solubility without an increasing film water vapor permeability.

  5. The Effects of Silk Protein Solution on Quality of Mangosteen

    Energy Technology Data Exchange (ETDEWEB)

    Phadvibulya, Valailak; Sudatis, Boonya; Panyarum, Kanyarat; Junsaithong, Mayuree [Thailand Institute of Nuclear Technology, Nakhon Nayok, (Thailand); Kerdchoechuen, Orapin [School of Bioresources and Technology, King Mongkuts University, Bangkok (Thailand)

    2011-06-15

    Full text: Sericin silk protein solution prepared from irradiated silk waste was applied as a wax coating on mangosteen fruits but was found not appropriate. Nonetheless, when the solution was sprayed onto fruits from the setting stage till maturity, it enhanced the fruit quality. Fruits showed a bigger stalk and greener, thicker and larger-angled calyx than untreated ones. They were edible after being kept at 25{sup C} for 3 to 4 weeks. Fruits sprayed with the silk protein solution and untreated fruits were separately harvested and packed for export. A half of them were irradiated with gamma radiation for insect eradication and then kept at 10{sup C} with 80 percents relative humidity. The unirradiated half was stored similarly. Results showed that rind color of irradiated fruits changed slower than unirradiated ones. However, silk protein solution spraying and irradiation did not affect fruit firmness and total soluble solids of mangosteen flesh. For sensory evaluation, it was found that sprayed and irradiated fruits showed no differences from the untreated ones in their physical properties, color, taste and odor. Fruits sprayed with the silk protein solution without irradiation had the longest shelf life of 6 weeks.

  6. Respiratory response of fifth-instar codling moth (Lepidoptera: Tortricidae) to rapidly changing temperatures.

    Science.gov (United States)

    Neven, L G

    1998-02-01

    Fifth-instar codling moth, Cydia pomonella (L.), larvae were exposed to 10 simulated heat treatments of apples and pears and CO2 levels were monitored as a measure of respiration. Marked increases in respiration rates (microliter CO2/mg/min) were noted during these treatments. Respiration peaked between 3.5 and 4.8 microliters CO2/mg/min; the amount of time to peak respiration depended on the heating rate and was correlated to the LT95. No differences were observed between male and female larvae in the timing of the peaks of CO2 production. In treatments where mortality occurred, CO2 levels dropped to zero, but only after a considerable time after death. Respiratory recovery rates, the time it took for CO2 levels to return to normal, were recorded after treatments at time points where CO2 production reached 3/4 and maximum peak. Respiration rates at constant temperatures were recorded within the range of 10-30 degrees C. Q10 over this range was 1.49, whereas Q10 was the greatest, 2.54, between 10 and 15 degrees C.

  7. Addition of selenium nanoparticles to electrospun silk scaffolds improves mammalian cell activity while reducing bacterial growth

    Directory of Open Access Journals (Sweden)

    Stanley Chung

    2016-07-01

    Full Text Available Silk possesses many beneficial wound healing properties, and electrospun scaffolds are especially applicable for skin applications, due to their smaller interstices and higher surface areas compared to non-electrospun equivalents. However, purified silk promotes microbial growth. In contrast, selenium nanoparticles have excellent antibacterial properties and are a novel antimicrobial chemistry. Here, electrospun silk scaffolds were doped with selenium nanoparticles to impart antibacterial properties to the silk scaffolds. Results showed significantly improved bacterial inhibition and improvement in human dermal fibroblast metabolic activity. These results suggest that the addition of selenium nanoparticles to electrospun silk is a promising approach to improve wound healing with reduced infection, without relying on antibiotics.

  8. Rapid nano impact printing of silk biopolymer thin films

    Science.gov (United States)

    White, Robert D.; Gray, Caprice; Mandelup, Ethan; Amsden, Jason J.; Kaplan, David L.; Omenetto, Fiorenzo G.

    2011-11-01

    In this paper, nano impact printing of silk biopolymer films is described. An indenter is rapidly accelerated and transfers the nanopattern from a silicon master into the silk film during an impact event that occurs in less than 1 ms. Contact stresses of greater than 100 MPa can be achieved during the short impact period with low power and inexpensive hardware. Ring shaped features with a diameter of 2 µm and a ring width of 100-200 nm were successfully transferred into untreated silk films using this method at room temperature. Mechanical modeling was carried out to determine the contact stress distribution, and demonstrates that imprinting can occur for contact stresses of less than 2 MPa. Thermal characterization at the impact location shows that raising the temperature to 70 °C has only a limited effect on pattern transfer. Contact stresses of greater than approximately 100 MPa result in excessive deformation of the film and poor pattern transfer.

  9. Rapid nano impact printing of silk biopolymer thin films

    International Nuclear Information System (INIS)

    White, Robert D; Gray, Caprice; Mandelup, Ethan; Amsden, Jason J; Kaplan, David L; Omenetto, Fiorenzo G

    2011-01-01

    In this paper, nano impact printing of silk biopolymer films is described. An indenter is rapidly accelerated and transfers the nanopattern from a silicon master into the silk film during an impact event that occurs in less than 1 ms. Contact stresses of greater than 100 MPa can be achieved during the short impact period with low power and inexpensive hardware. Ring shaped features with a diameter of 2 µm and a ring width of 100–200 nm were successfully transferred into untreated silk films using this method at room temperature. Mechanical modeling was carried out to determine the contact stress distribution, and demonstrates that imprinting can occur for contact stresses of less than 2 MPa. Thermal characterization at the impact location shows that raising the temperature to 70 °C has only a limited effect on pattern transfer. Contact stresses of greater than approximately 100 MPa result in excessive deformation of the film and poor pattern transfer.

  10. Beneficial Effects of Corn Silk on Metabolic Syndrome.

    Science.gov (United States)

    Wang, Bing; Xiao, Tiegang; Ruan, Jun; Liu, Wensheng

    2017-01-01

    Metabolic syndrome (MS) is a very common medical problem worldwide. It includes obesity, hypertension, hyperglycemia, and abnormal levels of triglycerides and high-density lipoprotein cholesterol. It is closely associated with insulin resistance and may lead to diabetes mellitus, liver diseases, or cardiovascular diseases. Corn silk (CS), a traditional Chinese medicine, has been reported to have multiple beneficial effects, including hypotensive, anti-diabetic, and hypolipidemic properties. This suggests that corn silk could be used to treat or prevent metabolic syndrome. In this review, we will discuss the potential role of corn silk in different components of metabolic syndrome. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Improved human tenocyte proliferation and differentiation in vitro by optimized silk degumming

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiao; Qiu Yiwei; Carr, Andrew J; Triffitt, James T; Sabokbar, Afsie; Xia Zhidao, E-mail: z.xia@swansea.ac.uk [Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford (United Kingdom)

    2011-06-15

    Tendon disorders are common clinical conditions. Tendon tissue engineering provides a new approach for tendon repair by integrating engineered substitutes with their native counterparts. Silk is considered to be a promising candidate for tendon engineering because of its biological and mechanical properties. However, a major concern with using silk for biomedical applications is the immune responses generated by sericin, a glue-like protein that coats the silk fibres. This study improves the existing protocols for silk 'degumming' which removes sericin and enables preparation of silk that is suitable for tendon regeneration. Bombyx mori silks were treated by sequential treatments with different proteases. The efficiency of degumming was determined by measuring weight loss, picric acid and carmine staining and scanning electron microscopy. To evaluate the cellular responses after degumming, the growth and differentiation of human tenocytes on silks were examined. The results showed that sequential protease treatment effectively degummed raw silks. The sequentially degummed silks showed enhanced tenocyte proliferation and upregulated mRNA levels of tendon markers. Thick cell multilayers formed on the treated silks, with cells and collagen fibres penetrating into the spaces in individual silk filaments, resulting in a structure resembling human tendon.

  12. Improved human tenocyte proliferation and differentiation in vitro by optimized silk degumming

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Wang; Yiwei, Qiu; Carr, Andrew J; Triffitt, James T; Sabokbar, Afsie; Xia Zhidao, E-mail: z.xia@swansea.ac.uk [Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford (United Kingdom)

    2011-06-15

    Tendon disorders are common clinical conditions. Tendon tissue engineering provides a new approach for tendon repair by integrating engineered substitutes with their native counterparts. Silk is considered to be a promising candidate for tendon engineering because of its biological and mechanical properties. However, a major concern with using silk for biomedical applications is the immune responses generated by sericin, a glue-like protein that coats the silk fibres. This study improves the existing protocols for silk 'degumming' which removes sericin and enables preparation of silk that is suitable for tendon regeneration. Bombyx mori silks were treated by sequential treatments with different proteases. The efficiency of degumming was determined by measuring weight loss, picric acid and carmine staining and scanning electron microscopy. To evaluate the cellular responses after degumming, the growth and differentiation of human tenocytes on silks were examined. The results showed that sequential protease treatment effectively degummed raw silks. The sequentially degummed silks showed enhanced tenocyte proliferation and upregulated mRNA levels of tendon markers. Thick cell multilayers formed on the treated silks, with cells and collagen fibres penetrating into the spaces in individual silk filaments, resulting in a structure resembling human tendon.

  13. Streaming submandibular gland

    International Nuclear Information System (INIS)

    Zajicek, G.; Yagil, C.; Michaeli, Y.

    1985-01-01

    Twenty female young adult rats were injected with tritiated thymidine ( 3 HTdR). The animals were then killed in groups of five, at the following times: 1 hour, and 4, 16, and 23 days. Autoradiograms of sections through the submandibular gland were prepared, and the location of labelled cells in relationship to tubuli and acini was recorded. The different tubular and acinar cross sections could be distinguished by their cell number. Narrow tubuli had fewer nuclei than the wider ones. The nuclear number of a cross section was defined as its class and the location of a labelled epithelial cell was expressed in relationship to the class where it was found. The location of a labelled stromal cell was determined by the class of its neighboring tubular or acinar cross sections. The mean cell numbers of intercalated, granular, and striated duct cross sections were, respectively, 4.7, 10.5, and 10.2, while the average cell content of acini was 4.7 cells. One hour after labelling most labelled tubular epithelial and stromal cells were found in tubular cross sections (or low tubular classes), while in the acini, labelled epithelial and stromal cells were found mainly in wider cross sections (or higher acinar classes). Within the next 23 days labelled tubular cells and stroma proceeded into higher classes, while labelled acinar epithelium and stroma cells were displaced into narrower cross sections (or lower classes). The displaced tubular epithelium and stroma covered daily 0.26 classes. At this velocity the cell will reach the highest tubular class in 62 days and the estimated maximal tubular cell life span is 62 days

  14. The osteogenic potential of mesoporous bioglasses/silk and non-mesoporous bioglasses/silk scaffolds in ovariectomized rats: in vitro and in vivo evaluation.

    Directory of Open Access Journals (Sweden)

    Ning Cheng

    Full Text Available Silk-based scaffolds have been introduced to bone tissue regeneration for years, however, their local therapeutic efficiency in bone metabolic disease condition has been seldom reported. According to our previous report, mesoporous bioactive glass (MBG/silk scaffolds exhibits superior in vitro bioactivity and in vivo osteogenic properties compared to non-mesoporous bioactive glass (BG/silk scaffolds, but no information could be found about their efficiency in osteoporotic (OVX environment. This study investigated a biomaterial-based approach for improving MSCs behavior in vitro, and accelerating OVX defect healing by using 3D BG/silk and MBG/silk scaffolds, and pure silk scaffolds as control. The results of SEM, CCK-8 assay and quantitative ALP activity showed that MBG/silk scaffolds can improve attachment, proliferation and osteogenic differentiation of both O-MSCs and sham control. In vivo therapeutic efficiency was evaluated by μCT analysis, hematoxylin and eosin staining, safranin O staining and tartrate-resistant acid phosphatase, indicating accelerated bone formation with compatible scaffold degradation and reduced osteoclastic response of defect healing in OVX rats after 2 and 4 weeks treatment, with a rank order of MBG/silk > BG/silk > silk group. Immunohistochemical markers of COL I, OPN, BSP and OCN also revealed that MBG/silk scaffolds can better induce accelerated collagen and non-collagen matrix production. The findings of this study suggest that MBG/silk scaffolds provide a better environment for cell attachment, proliferation and differentiation, and act as potential substitute for treating local osteoporotic defects.

  15. Quantitative analysis of allantoin in Iranian corn silk

    Directory of Open Access Journals (Sweden)

    E. Khanpour*

    2017-11-01

    Full Text Available Background and objectives: Zea mays is cultivated in different parts of Iran and corn silk is used in traditional medicine. Allantoin is one of the major compounds in corn silk. The purpose of this research was the quantitatve analysis of allantoin in corn silks belonging to several regions of Iran. Methods: The samples of corn silk were prepared from three provinces of Iran (Kermanshah, Fars and Razavi Khorasan. The dried plant materials were infused in boiling distilled water with a temperature of 90-95 °C on magnetic stirrer for 30 min. The levels of allantoin in aqueous extracts were determined by HPLC. Quantification was achieved using an C18 column (250×4.6 mm, 5 µm under isocratic conditions and phosphate buffer solution (pH 3.0 as the mobile phase at a flow rate of 0.5 mL/min. Column effluent was monitored at 210 nm. The calibration curve of allantoin standard was plotted with concentrations from 6.25 to 100 µg/mL. Results: The calibration curve of standard was linear over the concentration range used (R2=0.9999. The results showed that the amount of allantoin in samples was between 205 and 374 mg/100g of dry plant material. The corn silk samples of Razavi Khorasan and Fars provinces showed the lowest and highest amount of allantoin, respectively. Conclusion: The levels of allantoin obtained in this study were higher than the values reported in other studies; therefore, the researchers of this project are investigating the wound healing effect of corn silk.

  16. Design and Optimization of Resorbable Silk Internal Fixation Devices

    Science.gov (United States)

    Haas, Dylan S.

    Limitations of current material options for internal fracture fixation devices have resulted in a large gap between user needs and hardware function. Metal systems offer robust mechanical strength and ease of implantation but require secondary surgery for removal and/or result in long-term complications (infection, palpability, sensitivity, etc.). Current resorbable devices eliminate the need for second surgery and long-term complications but are still associated with negative host response as well as limited functionality and more difficult implantation. There is a definitive need for orthopedic hardware that is mechanically capable of immediate fracture stabilization and fracture fixation during healing, can safely biodegrade while allowing complete bone remodeling, can be resterilized for reuse, and is easily implantable (self-tapping). Previous work investigated the use of silk protein to produce resorbable orthopedic hardware for non- load bearing fracture fixation. In this study, silk orthopedic hardware was further investigated and optimized in order to better understand the ability of silk as a fracture fixation system and more closely meet the unfulfilled market needs. Solvent-based and aqueous-based silk processing formulations were cross-linked with methanol to induce beta sheet structure, dried, autoclaved and then machined to the desired device/geometry. Silk hardware was evaluated for dry, hydrated and fatigued (cyclic) mechanical properties, in vitro degradation, resterilization, functionalization with osteoinductive molecules and implantation technique for fracture fixation. Mechanical strength showed minor improvements from previous results, but remains comparable to current resorbable fixation systems with the advantages of self-tapping ability for ease of implantation, full degradation in 10 months, ability to be resterilized and reused, and ability to release molecules for osteoinudction. In vivo assessment confirmed biocompatibility, showed

  17. Orientational structure formation of silk fibroin with anisotropic properties in solutions

    International Nuclear Information System (INIS)

    Kholmuminov, A.A.

    2008-06-01

    Key words:silk fibroin, dissolution, solution's model systems, gelation, orientational crystallization, optical polarization, longitudinal stream, α - β transition, structure formation, phase transformations, relaxation, anisotropy of swelling and desorption, thermo- and biodegradation. Subjects of the inquiry: silk fibroin is the main subject of investigation. Fibroin's solutions were obtained on the base of water and organic solvents, containing salts. Comparative investigations were carried out by using biosolution - secretion of silkworm, solutions of silk sericin, cotton cellulose, methylcellulose, polystyrene and (co) polycrylonitrile. Aim of the inquiry: the elucidation of the regularities of silk fibroin anisotropic structures formation in the direct generation of orientational ordering in solutions taking into account of influences of its the molecular structures, configuration information, α - β conformational transformations, and development jointly using polarization-optical and hydrodynamic methods to control of structure formation. And also definition of possibility fields for use biopolymers anisotropic structure formation principles. Method of inquiry: birefringence, dispersion optical rotation, circular dichroism, polarization- ultramicroscope, ultracentrifuge, viscosimetry, potentiometry, differential thermal analysis, chromatography, x-ray analysis, spectroscopy. The results achieved and their novelty: the physical regularity amorphous-crystalline fibroin dissolutions in salt-containing solvents based on chains melting, distribution and redistribution were recognized; fibroin statistical parameters, molecular-mass and conformational characteristics were established; It was shown that fibroin molecules turned into fully uncoiled and oriented state with the breakdown decay of α-spiral chain sections by I type phase transition mechanism, but in oriented state with α-spiral conservation by II type transition; the presence of longitudinal field

  18. Laconicae cuspidis instar. The Correspondence of Justus Lipsius: 1598. Critical Edition with Introduction, Annotations and Stylistic Study

    OpenAIRE

    Deneire, Tom

    2009-01-01

    Dit doctoraat met als titel “Laconicae cuspidis instar”. De corresponden tie van Justus Lipsius: 1598. Kritische editie met inleiding, commentaar en stilistische studie betreft de correspondentie van de Brabantse huma nist Justus Lipsius (Joost Lips, Overijse 1547 - Leuven 1606) bewaard vo or het jaar 1598, en bestaat uit drie grote delen: A – Inleiding; B – IL E 98 (Kritische editie met commentaar) en C – Stilistische studie. * Deel A bevat na een preliminair ad lectorem en de bibliograf...

  19. Scanning electron microscopic (Sem studies on fourth instar larva and pupa of Anopheles (Cellia stephensi Liston (Anophelinae: Culicidae

    Directory of Open Access Journals (Sweden)

    Jagbir Singh Kirti

    2014-12-01

    Full Text Available Anopheles (Cellia stephensi Liston is a major vector species of malaria in Indian subcontinent. Taxonomists have worked on its various morphological aspects and immature stages to explore additional and new taxonomic attributes. Scanning electron microscopic (SEM studies have been conducted on the fourth instar larva and pupa of An. stephensi to find additional taxonomic features for the first time from Punjab state.

  20. Posterior spiracles of fourth instar larvae of four species of phlebotomine sand flies (Diptera: Psychodidae under scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Pessoa Felipe Arley Costa

    2000-01-01

    Full Text Available In the present study, posterior spiracles of laboratory-reared fourth instar larvae of Lutzomyia longipalpis, L. migonei, L. lenti, and L. whitmani (Diptera: Psychodidae of the State of Ceará, Brazil, were examined under scanning electron microscopy. The number of papillae of spiracles examined varied according to the species examined, but no intraspecific differences were found. The importance of this structure to sand fly larva identification and phylogeny is commented.

  1. Silk-Quality, Spinnability and Low Temperature Behavior

    Science.gov (United States)

    2015-12-02

    inert  atmosphere  (N2   gas   flow  rate  of  100  mL/min).  Changes   in  weight  percentage  during   temperature...Performance 3. DATES COVERED (From - To) 01-06-2012 to 31-05-2015 4. TITLE AND SUBTITLE Silk-Quality, Spinnability and Low Temperature Behaviour 5a...deploy the huge range in mechanical behaviour between different silk species and intra-species varieties. In particular, I set out to formulate a

  2. Corn silk induced cyclooxygenase-2 in murine macrophages.

    Science.gov (United States)

    Kim, Kyung A; Shin, Hyun-Hee; Choi, Sang Kyu; Choi, Hye-Seon

    2005-10-01

    Stimulation of murine macrophages with corn silk induced cyclooxygenase (COX)-2 with secretion of PGE2. Expression of COX-2 was inhibited by pyrolidine dithiocarbamate (PDTC), and increased DNA binding by nuclear factor kappa B (NF-kappaB), indicating that COX-2 induction proceeds also via the NF-kappaB signaling pathway. A specific inhibitor of COX-2 decreased the expression level of inducible nitric oxide synthase (iNOS) stimulated by corn silk. PGE2 elevated the expression level of iNOS, probably via EP2 and EP4 receptors on the surface of the macrophages.

  3. Structure determination of spider silk from X-ray images

    Energy Technology Data Exchange (ETDEWEB)

    Ulrich, Stephan; Zippelius, Annette [Universitaet Goettingen, Institut fuer Theoretische Physik (Germany); Meling, Martin [Max-Planck-Institut fuer biophysikalische Chemie, Goettingen (Germany); Glisovic, Anja; Salditt, Tim [Universitaet Goettingen, Institut fuer Roentgenphysik (Germany)

    2008-07-01

    Spider silk consists of interconnected crystallites, which are typically aligned along the fiber axis. We present a method to systematically determine the structure of these crystallites. Hereby we introduce a model that calculates the scattering function G(q) which is fitted to the measured X-ray image (silk from nephila clavipes). With it, the crystallites' size, the constitution and dimensions of their unit cell, as well as their tilt with respect to the fiber axis is identified, and furthermore the effect of coherent scattering from different crystallites is investigated. The shown methods and the presented model can easily be generalized to a wide class of composite materials.

  4. Basic Helix-Loop-Helix Transcription Factor Bmsage Is Involved in Regulation of fibroin H-chain Gene via Interaction with SGF1 in Bombyx mori

    Science.gov (United States)

    Li, Qiong-Yan; Hu, Wen-Bo; Zhou, Meng-Ting; Nie, Hong-Yi; Zhang, Yin-Xia; Peng, Zhang-Chuan; Zhao, Ping; Xia, Qing-You

    2014-01-01

    Silk glands are specialized in the synthesis of several secretory proteins. Expression of genes encoding the silk proteins in Bombyx mori silk glands with strict territorial and developmental specificities is regulated by many transcription factors. In this study, we have characterized B. mori sage, which is closely related to sage in the fruitfly Drosophila melanogaster. It is termed Bmsage; it encodes transcription factor Bmsage, which belongs to the Mesp subfamily, containing a basic helix–loop–helix motif. Bmsage transcripts were detected specifically in the silk glands of B. mori larvae through RT-PCR analysis. Immunoblotting analysis confirmed the Bmsage protein existed exclusively in B. mori middle and posterior silk gland cells. Bmsage has a low level of expression in the 4th instar molting stages, which increases gradually in the 5th instar feeding stages and then declines from the wandering to the pupation stages. Quantitative PCR analysis suggested the expression level of Bmsage in a high silk strain was higher compared to a lower silk strain on day 3 of the larval 5th instar. Furthermore, far western blotting and co-immunoprecipitation assays showed the Bmsage protein interacted with the fork head transcription factor silk gland factor 1 (SGF1). An electrophoretic mobility shift assay showed the complex of Bmsage and SGF1 proteins bound to the A and B elements in the promoter of fibroin H-chain gene(fib-H), respectively. Luciferase reporter gene assays confirmed the complex of Bmsage and SGF1 proteins increased the expression of fib-H. Together, these results suggest Bmsage is involved in the regulation of the expression of fib-H by being together with SGF1 in B. mori PSG cells. PMID:24740008

  5. Morphology and identification of first instar larvae of Australian blowflies of the genus Chrysomya of forensic importance.

    Science.gov (United States)

    Szpila, Krzysztof; Wallman, James F

    2016-10-01

    Light microscopy photographs, line illustrations and scanning electron microscopy micrographs are provided for first instar larvae of six Australian species of Chrysomya. All species have confirmed or potential in forensic investigations given their carrion-breeding habits. Morphology of the first instar larvae of Ch. nigripes, Ch. rufifacies, Ch. saffranea and Ch. varipes is revised, while larvae of Ch. incisularis and Ch. latifrons are described for the first time. The following morphological structures are documented: pseudocephalon, antennal complex, maxillary palpus, facial mask, thoracic and abdominal spinulation, spiracular field, posterior spiracles and cephaloskeleton. New diagnostic features of the cephaloskeleton and the spinulation of the abdominal segments are described. Verification of earlier descriptions revealed major discrepancies between published data, especially in the case of Ch. nigripes. The present results allow clarification, correction and, especially, complementation of the existing information provided by numerous authors. Finally, an identification key for first instar larvae of Australian necrophagous Chrysomya is presented. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. TOXICITY OF INSECTICIDES USED IN MUSKMELON ON FIRST-INSTAR LARVAE OF Chrysoperla genanigra FREITAS (NEUROPTERA: CHRYSOPIDAE

    Directory of Open Access Journals (Sweden)

    BÁRBARA KARINE DE ALBUQUERQUE SILVA

    2017-01-01

    Full Text Available Brazil is one of the world's largest producers of melon (Cucumis melo L., and Rio Grande do Norte and Ceará are the largest producers states of the country (99% of exports. This crop had great socio- economic importance in the Brazilian Northeast, however, it is affected by insect pests and consequently, large amounts of pesticides are applied to it, which greatly affect beneficial organisms, such as Chrysopidae. This bioassay evaluated the toxicity of nine insecticides used in commercial crops of muskmelon, applied to first- instar larvae of Chrysoperla genanigra of up to 24-hour-old, from mass rearing cultures. Sublethal effects were evaluated, classifying the insecticides into the toxicity classes recommended by the IOBC. A completely randomized design was used, consisting of ten treatments (clothianidin, pymetrozine, lambda-cyhalothrin, chlorantraniliprole, indoxacarb, pyriproxyfen, beta-cyfluthrin+imidacloprid, imidacloprid, beta-cypermethrin and a control consisted of distilled water. The treatments consisted of exposure of thirty larvae to dry residues of each product in Petri dishes, assessing their mortality, duration of instars, sex ratio, fecundity and viability of eggs from adults of the insects evaluated. The products were classified in toxicity classes as harmful (Class 4 (clothianidin, pymetrozine, indoxacarb, lambda-cyhalothrin, beta-cyfluthrin+imidacloprid, imidacloprid, beta- cypermethrin and pyriproxyfen and innocuous (Class 1 (chlorantraniliprole to first -instar larvae of C. genanigra, by calculate their total effect. Based on this work, chlorantraniliprole is the only recommended insecticide for use in integrated pest management (IPM programs in muskmelon crops.

  7. Rotational-echo Double-resonance in Complex Biopolymers: a Study of Nephila Clavipes Dragline Silk

    International Nuclear Information System (INIS)

    Michal, Carl A.; Jelinski, Lynn W.

    1998-01-01

    Rotational-Echo Double-Resonance (REDOR) NMR on strategically 13C and 15N labeled samples is used to study the conformation of the LGXQ (X = S, G, or N) motif in the major ampullate gland dragline silk from the spider Nephila clavipes. A method is described for calculating REDOR dephasing curves suitable for background subtractions, using probability distributions of nitrogen atoms surrounding a given carbon site, which are developed from coordinates in the Brookhaven Protein Data Bank. The validity of the method is established by comparison to dephasings observed from natural abundance 13C peaks for G and A. Straightforward fitting of universal REDOR dephasing curves to the background corrected peaks of interest provide results which are not self-consistent, and a more sophisticated analysis is developed which better accounts for 15N labels which have scrambled from the intended positions. While there is likely some heterogeneity in the structures formed by the LGXQ sequences, the data indicate that they all form compact turn-like structures

  8. Choice of hunting site as a consequence of experience in late-instar crab spiders.

    Science.gov (United States)

    Morse, Douglass H

    1999-08-01

    Earlier experiences may play an important role in the choice of hunting sites, but their effects on the foraging repertoire of most animals remain poorly understood. I tested the role of previous flower choices (hunting sites) by penultimate-instar female crab spiders Misumena vatia in making subsequent patch-choice decisions. M. vatia is a sit-and-wait predator, and the two flower species used, ox-eye daisy Chrysanthemum leucanthemum and common buttercup Ranunculus acris, are important hunting sites. Spiders with different immediate experience showed similar short-term (<1 day) giving-up times on the two flower species, independent of their previous substrate. However, four-fifths of the individuals that remained a day or longer tended to leave buttercups sooner than daisies, especially if they had previously occupied daisies. Thus they may directly assess the quality of a potential hunting site, perhaps in response to prey abundance, but previous experience may play a minor role as well. Of spiders that made several consecutive choices of hunting sites, those on daisies often confined these runs to daisies (one of two years); those on buttercups did not exhibit comparable fidelity. Spiders molting into the adult stage almost always subsequently chose the same flower species (either daisy or buttercup) as the one on which they molted. Thus, juvenile experiences may influence adults, the critical stage when virtually all of the spiders' reproductive resources are gathered, even if this resulted from imprinting on their molt sites rather than carrying information over the molt.

  9. Loblolly pine grown under elevated CO2 affects early instar pine sawfly performance.

    Science.gov (United States)

    Williams, R S; Lincoln, D E; Thomas, R B

    1994-06-01

    Seedlings of loblolly pine Pinus taeda (L.), were grown in open-topped field chambers under three CO 2 regimes: ambient, 150 μl l -1 CO 2 above ambient, and 300 μl l -1 CO 2 above ambient. A fourth, non-chambered ambient treatment was included to assess chamber effects. Needles were used in 96 h feeding trials to determine the performance of young, second instar larvae of loblolly pine's principal leaf herbivore, red-headed pine sawfly, Neodiprion lecontei (Fitch). The relative consumption rate of larvae significantly increased on plants grown under elevated CO 2 , and needles grown in the highest CO 2 regime were consumed 21% more rapidly than needles grown in ambient CO 2 . Both the significant decline in leaf nitrogen content and the substantial increase in leaf starch content contributed to a significant increase in the starch:nitrogen ratio in plants grown in elevated CO 2 . Insect consumption rate was negatively related to leaf nitrogen content and positively related to the starch:nitrogen ratio. Of the four volatile leaf monoterpenes measured, only β-pinene exhibited a significant CO 2 effect and declined in plants grown in elevated CO 2 . Although consumption changed, the relative growth rates of larvae were not different among CO 2 treatments. Despite lower nitrogen consumption rates by larvae feeding on the plants grown in elevated CO 2 , nitrogen accumulation rates were the same for all treatments due to a significant increase in nitrogen utilization efficiency. The ability of this insect to respond at an early, potentially susceptible larval stage to poorer food quality and declining levels of a leaf monoterpene suggest that changes in needle quality within pines in future elevated-CO 2 atmospheres may not especially affect young insects and that tree-feeding sawflies may respond in a manner similar to herb-feeding lepidopterans.

  10. Structure to function: Spider silk and human collagen

    Science.gov (United States)

    Rabotyagova, Olena S.

    Nature has the ability to assemble a variety of simple molecules into complex functional structures with diverse properties. Collagens, silks and muscles fibers are some examples of fibrous proteins with self-assembling properties. One of the great challenges facing Science is to mimic these designs in Nature to find a way to construct molecules that are capable of organizing into functional supra-structures by self-assembly. In order to do so, a construction kit consisting of molecular building blocks along with a complete understanding on how to form functional materials is required. In this current research, the focus is on spider silk and collagen as fibrous protein-based biopolymers that can shed light on how to generate nanostructures through the complex process of self-assembly. Spider silk in fiber form offers a unique combination of high elasticity, toughness, and mechanical strength, along with biological compatibility and biodegrability. Spider silk is an example of a natural block copolymer, in which hydrophobic and hydrophilic blocks are linked together generating polymers that organize into functional materials with extraordinary properties. Since silks resemble synthetic block copolymer systems, we adopted the principles of block copolymer design from the synthetic polymer literature to build block copolymers based on spider silk sequences. Moreover, we consider spider silk to be an important model with which to study the relationships between structure and properties in our system. Thus, the first part of this work was dedicated to a novel family of spider silk block copolymers, where we generated a new family of functional spider silk-like block copolymers through recombinant DNA technology. To provide fundamental insight into relationships between peptide primary sequence, block composition, and block length and observed morphological and structural features, we used these bioengineered spider silk block copolymers to study secondary structure

  11. Enhancing analysis of cells and proteins by fluorescence imaging on silk-based biomaterials: modulating the autofluorescence of silk.

    Science.gov (United States)

    Neo, Puay Yong; Tan, Daryl Jian-An; Shi, Pujiang; Toh, Siew Lok; Goh, James Cho-Hong

    2015-02-01

    Silk is a versatile and established biomaterial for various tissue engineering purposes. However, it also exhibits strong autofluorescence signals-thereby hindering fluorescence imaging analysis of cells and proteins on silk-derived biomaterials. Sudan Black B (SB) is a lysochrome dye commonly used to stain lipids in histology. It has also been reported to be able to quench autofluorescence of tissues in histology and has been tested on artificial biomedical polymers in recent years. It was hypothesized that SB would exert similar quenching effects on silk, modulating the autofluorescence signals, and thereby enabling improved imaging analysis of cells and molecules of interests. The quenching effect of SB on the intrinsic fluorescence properties of silk and on commercial fluorescent dyes were first investigated in this study. SB was then incorporated into typical fluorescence-based staining protocols to study its effectiveness in improving fluorescence-based imaging of the cells and proteins residing with the silk-based biomaterials. Silk processed into various forms of biomaterials (e.g., films, sponges, fibers, and electrospun mats) was seeded with cells and cultured in vitro. At sacrificial time points, specimens were harvested, fixed, and prepared for fluorescence staining. SB, available commercially as a powder, was dissolved in 70% ethanol (0.3% [w/v]) to form staining solutions. SB treatment was introduced at the last step of typical immunofluorescence staining protocols for 15-120 min. For actin staining protocols by phalloidin toxin, SB staining solutions were added before and after permeabilization with Triton-X for 15-30 min. Results showed that ideal SB treatment duration is about 15 min. Apart from being able to suppress the autofluorescence of silk, this treatment duration was also not too long to adversely affect the fluorescent labeling probes used. The relative improvement brought about by SB treatment was most evident in the blue and green

  12. Bioprospecting finds the toughest biological material: extraordinary silk from a giant riverine orb spider.

    Directory of Open Access Journals (Sweden)

    Ingi Agnarsson

    Full Text Available BACKGROUND: Combining high strength and elasticity, spider silks are exceptionally tough, i.e., able to absorb massive kinetic energy before breaking. Spider silk is therefore a model polymer for development of high performance biomimetic fibers. There are over 41,000 described species of spiders, most spinning multiple types of silk. Thus we have available some 200,000+ unique silks that may cover an amazing breadth of material properties. To date, however, silks from only a few tens of species have been characterized, most chosen haphazardly as model organisms (Nephila or simply from researchers' backyards. Are we limited to 'blindly fishing' in efforts to discover extraordinary silks? Or, could scientists use ecology to predict which species are likely to spin silks exhibiting exceptional performance properties? METHODOLOGY: We examined the biomechanical properties of silk produced by the remarkable Malagasy 'Darwin's bark spider' (Caerostris darwini, which we predicted would produce exceptional silk based upon its amazing web. The spider constructs its giant orb web (up to 2.8 m(2 suspended above streams, rivers, and lakes. It attaches the web to substrates on each riverbank by anchor threads as long as 25 meters. Dragline silk from both Caerostris webs and forcibly pulled silk, exhibits an extraordinary combination of high tensile strength and elasticity previously unknown for spider silk. The toughness of forcibly silked fibers averages 350 MJ/m(3, with some samples reaching 520 MJ/m(3. Thus, C. darwini silk is more than twice tougher than any previously described silk, and over 10 times better than Kevlar®. Caerostris capture spiral silk is similarly exceptionally tough. CONCLUSIONS: Caerostris darwini produces the toughest known biomaterial. We hypothesize that this extraordinary toughness coevolved with the unusual ecology and web architecture of these spiders, decreasing the likelihood of bridgelines breaking and collapsing the web

  13. Response of human corneal fibroblasts on silk film surface patterns.

    Science.gov (United States)

    Gil, Eun Seok; Park, Sang-Hyug; Marchant, Jeff; Omenetto, Fiorenzo; Kaplan, David L

    2010-06-11

    Transparent, biodegradable, mechanically robust, and surface-patterned silk films were evaluated for the effect of surface morphology on human corneal fibroblast (hCF) cell proliferation, orientation, and ECM deposition and alignment. A series of dimensionally different surface groove patterns were prepared from optically graded glass substrates followed by casting poly(dimethylsiloxane) (PDMS) replica molds. The features on the patterned silk films showed an array of asymmetric triangles and displayed 37-342 nm depths and 445-3 582 nm widths. hCF DNA content on all patterned films were not significantly different from that on flat silk films after 4 d in culture. However, the depth and width of the grooves influenced cell alignment, while the depth differences affected cell orientation; overall, deeper and narrower grooves induced more hCF orientation. Over 14 d in culture, cell layers and actin filament organization demonstrated that confluent hCFs and their cytoskeletal filaments were oriented along the direction of the silk film patterned groove axis. Collagen type V and proteoglycans (decorin and biglycan), important markers of corneal stromal tissue, were highly expressed with alignment. Understanding corneal stromal fibroblast responses to surface features on a protein-based biomaterial applicable in vivo for corneal repair potential suggests options to improve corneal tissue mimics. Further, the approaches provide fundamental biomaterial designs useful for bioengineering oriented tissue layers, an endemic feature in most biological tissue structures that lead to critical tissue functions.

  14. Visual responses of corn silk flies (Diptera: Ulidiidae)

    Science.gov (United States)

    Corn silk flies are major pests impacting fresh market sweet corn production in Florida and Georgia. Control depends solely on well-times applications of insecticides to protect corn ear development. Surveillance depends on visual inspection of ears with no effective trapping methods currently ava...

  15. Antibiotic-Releasing Silk Biomaterials for Infection Prevention and Treatment

    OpenAIRE

    Pritchard, Eleanor M.; Valentin, Thomas; Panilaitis, Bruce; Omenetto, Fiorenzo; Kaplan, David L.

    2012-01-01

    Effective treatment of infections in avascular and necrotic tissues can be challenging due to limited penetration into the target tissue and systemic toxicities. Controlled release polymer implants have the potential to achieve the high local concentrations needed while also minimizing systemic exposure. Silk biomaterials possess unique characteristics for antibiotic delivery including biocompatibility, tunable biodegradation, stabilizing effects, water-based processing and diverse material f...

  16. Differential scanning fluorimetry illuminates silk feedstock stability and processability

    Czech Academy of Sciences Publication Activity Database

    Dicko, C.; Kasoju, Naresh; Hawkins, N.; Vollrath, F.

    2016-01-01

    Roč. 12, č. 1 (2016), s. 255-262 ISSN 1744-683X R&D Projects: GA MŠk(CZ) EE2.3.30.0029 Institutional support: RVO:61389013 Keywords : differential scanning fluorimetry * biomaterials * silk fibroin Subject RIV: CE - Biochemistry Impact factor: 3.889, year: 2016

  17. Silk cocoon drying in forced convection type solar dryer

    International Nuclear Information System (INIS)

    Singh, Panna Lal

    2011-01-01

    The thin layer silk cocoon drying was studied in a forced convection type solar dryer. The drying chamber was provided with several trays on which the cocoons loaded in thin layer. The hot air generated in the solar air heater was forced into drying chamber to avoid the direct exposure of sunlight and UV radiation on cocoons. The drying air temperature varied from 50 to 75 o C. The cocoon was dried from the initial moisture content of about 60-12% (wb). The drying data was fitted to thin layer drying models. Drying behaviour of the silk cocoon was best fitted with the Wang and Singh drying model. Good agreement was obtained between predicted and experimental values. Quality of the cocoons dried in the solar dryer was at par with the cocoons dried in the conventional electrical oven dryer in term of the silk yield and strength of the silk. Saving of electrical energy was about 0.75 kWh/kg cocoons dried. Economic analysis indicated that the NPV of the solar dryer was higher and more stable (against escalation rate of electricity) as compare to the same for electrical oven dryer. Due to simplicity in design and construction and significant saving of operational electrical energy, solar cocoon dryer seems to be a viable option.

  18. The Political Economics of the New Silk Road

    Directory of Open Access Journals (Sweden)

    Sárvári Balázs

    2016-02-01

    Full Text Available What has now been coined the term XXI Century Silk Road had evolved from a speech given by Chinese premier Xi Jinping in Kazakhstan in 2013. It was initially a plan aimed at promoting the bilateral relations of China and its neighbors; however, the initiative had since then traversed the region’s borders and become a global project.

  19. Silk for silver : Dutch-Vietnamese relations, 1637-1700

    NARCIS (Netherlands)

    Hoang Anh Tuan,

    2006-01-01

    Against the background of a regional crisis caused by dynastic change in China and the closure of Japan in the middle of the seventeenth century, the Vietnamese kingdom of Tonkin rose to the fore as the major silk producing and exporting region in East Asia. Based on a wealth of so far unused

  20. Silk fibroin as biomaterial for bone tissue engineering.

    Science.gov (United States)

    Melke, Johanna; Midha, Swati; Ghosh, Sourabh; Ito, Keita; Hofmann, Sandra

    2016-02-01

    Silk fibroin (SF) is a fibrous protein which is produced mainly by silkworms and spiders. Its unique mechanical properties, tunable biodegradation rate and the ability to support the differentiation of mesenchymal stem cells along the osteogenic lineage, have made SF a favorable scaffold material for bone tissue engineering. SF can be processed into various scaffold forms, combined synergistically with other biomaterials to form composites and chemically modified, which provides an impressive toolbox and allows SF scaffolds to be tailored to specific applications. This review discusses and summarizes recent advancements in processing SF, focusing on different fabrication and functionalization methods and their application to grow bone tissue in vitro and in vivo. Potential areas for future research, current challenges, uncertainties and gaps in knowledge are highlighted. Silk fibroin is a natural biomaterial with remarkable biomedical and mechanical properties which make it favorable for a broad range of bone tissue engineering applications. It can be processed into different scaffold forms, combined synergistically with other biomaterials to form composites and chemically modified which provides a unique toolbox and allows silk fibroin scaffolds to be tailored to specific applications. This review discusses and summarizes recent advancements in processing silk fibroin, focusing on different fabrication and functionalization methods and their application to grow bone tissue in vitro and in vivo. Potential areas for future research, current challenges, uncertainties and gaps in knowledge are highlighted. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Redoable Tie-Over Dressing Using Multiple Loop Silk Threads

    Directory of Open Access Journals (Sweden)

    Hyeon Jong Jo

    2013-05-01

    Full Text Available After skin grafting, to prevent hematoma or seroma collection at the graft site, a tie-over dressing has been commonly used. However, although the conventional tie-over dressing by suture is a useful method for securing a graft site, refixation is difficult when repeated tie-over dressing is needed. Therefore, we recommend a redoable tie-over dressing technique with multiple loops threads and connecting silk threads. After the raw surface of each of our cases was covered with a skin graft, multiple loop silk thread attached with nylon at the skin graft margin. We applied the ointment gauze and wet cotton/fluffy gauze over the skin graft, then fixed the dressing by connecting cross-counter multiple loop thread with connecting silk threads. When we opened the tie-over dressing by cutting the connecting silk threads, we repeated the tie-over dressing with the same method. The skin graft was taken successfully without hematoma or seroma collection or any other complications. In conclusion, we report a novel tie-over dressing enabling simple fixation of the dressing to maintain proper tension for wounds that require repetitive fixation. Further, with this reliable method, the skin grafts were well taken.

  2. Redoable Tie-Over Dressing Using Multiple Loop Silk Threads

    Directory of Open Access Journals (Sweden)

    Hyeon Jong Jo

    2013-05-01

    Full Text Available After skin grafting, to prevent hematoma or seroma collection at the graft site, a tie-over dressing has been commonly used. However, although the conventional tie-over dressing by suture is a useful method for securing a graft site, refixation is difficult when repeated tieover dressing is needed. Therefore, we recommend a redoable tie-over dressing technique with multiple loops threads and connecting silk threads. After the raw surface of each of our cases was covered with a skin graft, multiple loop silk thread attached with nylon at the skin graft margin. We applied the ointment gauze and wet cotton/fluffy gauze over the skin graft, then fixed the dressing by connecting cross-counter multiple loop thread with connecting silk threads. When we opened the tie-over dressing by cutting the connecting silk threads, we repeated the tie-over dressing with the same method. The skin graft was taken successfully without hematoma or seroma collection or any other complications. In conclusion, we report a novel tie-over dressing enabling simple fixation of the dressing to maintain proper tension for wounds that require repetitive fixation. Further, with this reliable method, the skin grafts were well taken.

  3. Silk fibroin as an organic polymer for controlled drug delivery

    NARCIS (Netherlands)

    Hofmann, S.; Foo, S.; Rossetti, F.; Textor, M.; Vunjak-Novakovic, G.; Kaplan, D.L.; Merkle, H.P.; Meinel, L.

    2006-01-01

    The pharmaceutical utility of silk fibroin (SF) materials for drug delivery was investigated. SF films were prepared from aqueous solutions of the fibroin protein polymer and crystallinity was induced and controlled by methanol treatment. Dextrans of different molecular weights, as well as proteins,

  4. Conservation of silk genes in Trichoptera and Lepidoptera

    Czech Academy of Sciences Publication Activity Database

    Yonemura, N.; Mita, K.; Tamura, T.; Sehnal, František

    2009-01-01

    Roč. 68, č. 6 (2009), s. 641-653 ISSN 0022-2844 R&D Projects: GA AV ČR IAA5007402 Institutional research plan: CEZ:AV0Z50070508 Keywords : silk evolution * Trichoptera * Lepidoptera Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.323, year: 2009

  5. Nutrient Deprivation Induces Property Variations in Spider Gluey Silk

    Science.gov (United States)

    Blamires, Sean J.; Sahni, Vasav; Dhinojwala, Ali; Blackledge, Todd A.; Tso, I-Min

    2014-01-01

    Understanding the mechanisms facilitating property variability in biological adhesives may promote biomimetic innovations. Spider gluey silks such as the spiral threads in orb webs and the gumfoot threads in cobwebs, both of which comprise of an axial thread coated by glue, are biological adhesives that have variable physical and chemical properties. Studies show that the physical and chemical properties of orb web gluey threads change when spiders are deprived of food. It is, however, unknown whether gumfoot threads undergo similar property variations when under nutritional stress. Here we tested whether protein deprivation induces similar variations in spiral and gumfoot thread morphology and stickiness. We manipulated protein intake for the orb web spider Nephila clavipes and the cobweb spider Latrodectus hesperus and measured the diameter, glue droplet volume, number of droplets per mm, axial thread width, thread stickiness and adhesive energy of their gluey silks. We found that the gluey silks of both species were stickier when the spiders were deprived of protein than when the spiders were fed protein. In N. clavipes a concomitant increase in glue droplet volume was found. Load-extension curves showed that protein deprivation induced glue property variations independent of the axial thread extensions in both species. We predicted that changes in salt composition of the glues were primarily responsible for the changes in stickiness of the silks, although changes in axial thread properties might also contribute. We, additionally, showed that N. clavipes' glue changes color under protein deprivation, probably as a consequence of changes to its biochemical composition. PMID:24523902

  6. Co-effect of silk and amniotic membrane for tendon repair.

    Science.gov (United States)

    Seo, Young-Kwon; Kim, Jun-Hyung; Eo, Su-Rak

    2016-08-01

    The objective of the present study was to determine the feasibility and biocompatibility of a silk scaffold and a composite silk scaffold in terms of new tendon generation using a rabbit Achilles tendon model. The silk scaffold was constructed using a weaving machine, then soaked in a 1% collagen-hyaluronan (HA) solution and air-dried, whereas the composite silk scaffold was composed of a silk scaffold containing a lyophilized collagen-HA substrate. Tenocytes were cultured in vitro to compare cell populations in the two groups. The cellular densities on composite silk scaffolds were 40% higher on average than those on silk scaffolds in 30-day tenocyte cultures. The tendon scaffolds had implanted into Achilles tendon defects in 16 white New Zealand rabbits. Rabbits were randomly divided into the following three groups: group I, silk scaffold alone; group II, composite silk scaffold; and group III, composite silk scaffold wrapped by an amniotic membrane. Implants were harvested 2, 8, and 12 weeks post-implantation. Histological examinations were conducted using hematoxylin-eosin (H&E), Masson's trichrome, and by performing immunohistochemical staining for CD34. After 12 weeks, the three groups were distinguishable based on gross examination. The histological examination revealed more organized collagen fibrils in groups III, which showed a dense, parallel, linear organization of collagen bundles. CD34 staining revealed neoangiogenesis in groups III. The results of this research showed that collagen-HA substrates with amniotic membrane accelerate cellular migration and angiogenesis in neotendons.

  7. Thermal Performance Testing of Cryogenic Multilayer Insulation with Silk Net Spacers

    International Nuclear Information System (INIS)

    Johnson, W L; Frank, D J; Nast, T C; Fesmire, J E

    2015-01-01

    Early comprehensive testing of cryogenic multilayer insulation focused on the use of silk netting as a spacer material. Silk netting was used for multiple test campaigns that were designed to provide baseline thermal performance estimates for cryogenic insulation systems. As more focus was put on larger systems, the cost of silk netting became a deterrent and most aerospace insulation firms were using Dacron (or polyester) netting spacers by the early 1970s. In the midst of the switch away from silk netting there was no attempt to understand the difference between silk and polyester netting, though it was widely believed that the silk netting provided slightly better performance. Without any better reference for thermal performance data, the silk netting performance correlations continued to be used. In order to attempt to quantify the difference between the silk netting and polyester netting, a brief test program was developed. The silk netting material was obtained from Lockheed Martin and was tested on the Cryostat-100 instrument in three different configurations, 20 layers with both single and double netting and 10 layers with single netting only. The data show agreement within 15 - 30% with the historical silk netting based correlations and show a substantial performance improvement when compared to previous testing performed using polyester netting and aluminum foil/fiberglass paper multilayer insulation. Additionally, the data further reinforce a recently observed trend that the heat flux is not directly proportional to the number of layers installed on a system. (paper)

  8. Genetic engineered color silk: fabrication of a photonics material through a bioassisted technology.

    Science.gov (United States)

    Shimizu, Katsuhiko

    2018-05-15

    Silk produced by the silkworm Bombyx mori is an attractive material because of its luster, smooth and soft texture, conspicuous mechanical strength, good biocompatibility, slow biodegradation, and carbon neutral synthesis. Silkworms have been domesticated and bred for production of better quality and quantity of silk, resulting in the development of sericulture and the textile industry. Silk is generally white, so dyeing is required to obtain colored fiber. However, the dyeing process involves harsh conditions and generates a large volume of waste water, which have environmentally and economically negative impacts. Although some strains produce cocoons that contain pigments derived from the mulberry leaves that they eat, the pigments are distributed in the sericin layer and are lost during gumming. In trials for production of colored silk by feeding silkworms on diets containing dyes, only limited species of dye molecules were incorporated into the silk threads. A method for the generation of transgenic silkworm was established in conjunction with the discovery of green fluorescent protein (GFP), and silkworms carrying the GFP gene spun silk threads that formed cocoons that glowed bright green and still retained the original properties of silk. A wide range of color variation of silk threads has been obtained by replacing the GFP gene with the genes of other fluorescent proteins chosen from the fluorescent protein palette. The genetically modified silk with photonic properties can be processed to form various products including linear threads, 2D fabrics, and 3D materials. The transgenic colored silk could be economically advantageous due to addition of a new value to silk and reduction of cost for water waste, and environmentally preferable for saving water. Here, I review the literature regarding the production methods of fluorescent silk from transgenic silkworms and present examples of genetically modified color silk.

  9. Osteoinductive recombinant silk fusion proteins for bone regeneration.

    Science.gov (United States)

    Dinjaski, Nina; Plowright, Robyn; Zhou, Shun; Belton, David J; Perry, Carole C; Kaplan, David L

    2017-02-01

    Protein polymers provide a unique opportunity for tunable designs of material systems due to the genetic basis of sequence control. To address the challenge of biomineralization interfaces with protein based materials, we genetically engineered spider silks to design organic-inorganic hybrid systems. The spider silk inspired domain (SGRGGLGGQG AGAAAAAGGA GQGGYGGLGSQGT) 15 served as an organic scaffold to control material stability and to allow multiple modes of processing, whereas the hydroxyapatite binding domain VTKHLNQISQSY (VTK), provided control over osteogenesis. The VTK domain was fused either to the N-, C- or both terminals of the spider silk domain to understand the effect of position on material properties and mineralization. The addition of the VTK domain to silk did not affect the physical properties of the silk recombinant constructs, but it had a critical role in the induction of biomineralization. When the VTK domain was placed on both the C- and N-termini the formation of crystalline hydroxyapatite was significantly increased. In addition, all of the recombinant proteins in film format supported the growth and proliferation of human mesenchymal stem cells (hMSCs). Importantly, the presence of the VTK domain enhanced osteoinductive properties up to 3-fold compared to the control (silk alone without VTK). Therefore, silk-VTK fusion proteins have been shown suitable for mineralization and functionalization for specific biomedical applications. Organic-inorganic interfaces are integral to biomaterial functions in many areas of repair and regeneration. Several protein polymers have been investigated for this purpose. Despite their success the limited options to fine-tune their material properties, degradation patterns and functionalize them for each specific biomedical application limits their application. Various studies have shown that the biological performance of such proteins can be improved by genetic engineering. The present study provides data

  10. The neuro secretory activity in the permanent nymphs of schistocerca gregarea (Forskal) as a result of gamma irradiation of the third nymphal instar

    International Nuclear Information System (INIS)

    Elgammal, A.M.; Abdelsalam, K.A.; Mourad, A.K.

    1986-01-01

    Laboratory studies were carried out to evaluate the effect of different doses of gamma radiation on the neuro secretory activity in the permanent nymphs of schistocerca gregaria by treating them in the third nymphal instar. Treatment with 30 gray induced complete mortality for all treated nymphs. However, irradiation with a dose of 20 gray produced fourth instar nymphs which entered a state of suspended development for about 14 days. Exposure to a dose of 10 gray induced three types of response associated with the endocrine activities. Some of the treated nymphs developed to the fifth instar with soft and thin cuticle without tanning or darkening, these nymphs did not survive more than a few hours after ecdysis. Others became fifth instar with anomalous wings and normal cuticle, these survived about 18 days as permanent fifth instar nymphs before dying. The rest molted to permanent fourth instar that survived more than one month and eventually died. Corporal allata (CA) volume in the permanent nymphs were estimated by planimeter method, revealing a pronounced reduction in their size in comparison with the untreated control. This reflects a sharp inhibition in their synthetic activity of juvenile hormone (J H). It is assumed that the permanent nymphs were produced as a result of direct effect on the cerebral neuro secretory cells of the brain, the source of stimulation for J H an decdysone production. In the main time, gamma rays prevented the production of the tanning and darkening factor (Bursicon hormone) in these cells.1 fig.,3 tab

  11. [Meibomian gland disfunction in computer vision syndrome].

    Science.gov (United States)

    Pimenidi, M K; Polunin, G S; Safonova, T N

    2010-01-01

    This article reviews ethiology and pathogenesis of dry eye syndrome due to meibomian gland disfunction (MDG). It is showed that blink rate influences meibomian gland functioning and computer vision syndrome development. Current diagnosis and treatment options of MDG are presented.

  12. Imaging of the major salivary glands

    DEFF Research Database (Denmark)

    Afzelius, Pia; Nielsen, Ming-Yuan; Ewertsen, Caroline

    2016-01-01

    The major salivary glands, submandibular, parotid and sublingual glands play an important role in preserving the oral cavity and dental health. Patients with problems of the major salivary glands may present with symptoms such as dry mouth, dysphagia and obstruction of duct, inflammation, severe...

  13. [Brunners gland hiperplasia. Report of two cases].

    Science.gov (United States)

    Padilla Ruiz, Maykel

    2014-04-01

    Brunner's gland hyperplasia is an infrequent benign injury located on the first or second portion of the duodenum. The disease spectrum includes diffuse nodular hyperplasia, circumscribed nodular hyperplasia, and Brunner's gland adenoma. We report two cases, one with an adenoma of Brunner's glands as a duodenal polyp and the other as a diffuse nodular hyperplasia of the duodenal bulb.

  14. Sample selection, preparation methods, and the apparent tensile properties of silkworm (B. mori) cocoon silk.

    Science.gov (United States)

    Reed, Emily J; Bianchini, Lindsay L; Viney, Christopher

    2012-06-01

    Reported literature values of the tensile properties of natural silk cover a wide range. While much of this inconsistency is the result of variability that is intrinsic to silk, some is also a consequence of differences in the way that silk is prepared for tensile tests. Here we explore how measured mechanical properties of Bombyx mori cocoon silk are affected by two intrinsic factors (the location from which the silk is collected within the cocoon, and the color of the silk), and two extrinsic factors (the storage conditions prior to testing, and different styles of reeling the fiber). We find that extrinsic and therefore controllable factors can affect the properties more than the intrinsic ones studied. Our results suggest that enhanced inter-laboratory collaborations, that lead to standardized sample collection, handling, and storage protocols prior to mechanical testing, would help to decrease unnecessary (and complicating) variation in reported tensile properties. Copyright © 2011 Wiley Periodicals, Inc.

  15. Concentration state dependence of the rheological and structural properties of reconstituted silk.

    Science.gov (United States)

    Mo, Chunli; Holland, Chris; Porter, David; Shao, Zhengzhong; Vollrath, Fritz

    2009-10-12

    The ability to control the processing of artificial silk is key to the successful application of this important and high performance biopolymer. Understanding where our current reconstitution process can be improved will not only aid us in the creation of better materials, but will also provide insight into the natural material along the way. This study aims to understand what proportion of reconstituted silk contributes to its rheological properties and what conformational state the silk proteins are in. It shows, for the first time, that a change in rheological properties can be related to a change in silk structures present in solution and reveals a low concentration gel state for silk that may have important implications for future successful artificial processing of silk.

  16. Invited review current progress and limitations of spider silk for biomedical applications.

    Science.gov (United States)

    Widhe, Mona; Johansson, Jan; Hedhammar, My; Rising, Anna

    2012-06-01

    Spider silk is a fascinating material combining remarkable mechanical properties with low density and biodegradability. Because of these properties and historical descriptions of medical applications, spider silk has been proposed to be the ideal biomaterial. However, overcoming the obstacles to produce spider silk in sufficient quantities and in a manner that meets regulatory demands has proven to be a difficult task. Also, there are relatively few studies of spider silk in biomedical applications available, and the methods and materials used vary a lot. Herein we summarize cell culture- and in vivo implantation studies of natural and synthetic spider silk, and also review the current status and future challenges in the quest for a large scale production of spider silk for medical applications. Copyright © 2011 Wiley Periodicals, Inc.

  17. Investigation of synthetic spider silk crystallinity and alignment via electrothermal, pyroelectric, literature XRD, and tensile techniques.

    Science.gov (United States)

    Munro, Troy; Putzeys, Tristan; Copeland, Cameron G; Xing, Changhu; Lewis, Randolph V; Ban, Heng; Glorieux, Christ; Wubbenhorst, Michael

    2017-04-01

    The processes used to create synthetic spider silk greatly affect the properties of the produced fibers. This paper investigates the effect of process variations during artificial spinning on the thermal and mechanical properties of the produced silk. Property values are also compared to the ones of the natural dragline silk of the N. clavipes spider, and to unprocessed (as-spun) synthetic silk. Structural characterization by scanning pyroelectric microscopy is employed to provide insight into the axial orientation of the crystalline regions of the fiber and is supported by XRD data. The results show that stretching and passage through liquid baths induce crystal formation and axial alignment in synthetic fibers, but with different structural organization than natural silks. Furthermore, an increase in thermal diffusivity and elastic modulus is observed with decreasing fiber diameter, trending towards properties of natural fiber. This effect seems to be related to silk fibers being subjected to a radial gradient during production.

  18. Spider genomes provide insight into composition and evolution of venom and silk

    Science.gov (United States)

    Sanggaard, Kristian W.; Bechsgaard, Jesper S.; Fang, Xiaodong; Duan, Jinjie; Dyrlund, Thomas F.; Gupta, Vikas; Jiang, Xuanting; Cheng, Ling; Fan, Dingding; Feng, Yue; Han, Lijuan; Huang, Zhiyong; Wu, Zongze; Liao, Li; Settepani, Virginia; Thøgersen, Ida B.; Vanthournout, Bram; Wang, Tobias; Zhu, Yabing; Funch, Peter; Enghild, Jan J.; Schauser, Leif; Andersen, Stig U.; Villesen, Palle; Schierup, Mikkel H; Bilde, Trine; Wang, Jun

    2014-01-01

    Spiders are ecologically important predators with complex venom and extraordinarily tough silk that enables capture of large prey. Here we present the assembled genome of the social velvet spider and a draft assembly of the tarantula genome that represent two major taxonomic groups of spiders. The spider genomes are large with short exons and long introns, reminiscent of mammalian genomes. Phylogenetic analyses place spiders and ticks as sister groups supporting polyphyly of the Acari. Complex sets of venom and silk genes/proteins are identified. We find that venom genes evolved by sequential duplication, and that the toxic effect of venom is most likely activated by proteases present in the venom. The set of silk genes reveals a highly dynamic gene evolution, new types of silk genes and proteins, and a novel use of aciniform silk. These insights create new opportunities for pharmacological applications of venom and biomaterial applications of silk. PMID:24801114

  19. Dissolvable Films of Silk Fibroin for Ultrathin Conformal Bio-Integrated Electronics

    Science.gov (United States)

    2010-06-01

    implantation. *A full list of authors and their affiliations appears at the end of the paper. Silk is an appealing biopolymer as a temporary, soluble...18 APR 2010 2. REPORT TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Dissolvable films of silk fibroin for ultrathin...10.1038/NMAT2745 Dissolvable films of silk fibroin for ultrathin conformal bio-integrated electronics Dae-Hyeong Kim and Jonathan Viventi et al

  20. Graphene oxide from silk cocoon: a novel magnetic fluorophore for multi-photon imaging

    OpenAIRE

    Roy, Manas; Kusurkar, Tejas Sanjeev; Maurya, Sandeep Kumar; Meena, Sunil Kumar; Singh, Sushil Kumar; Sethy, Niroj; Bhargava, Kalpana; Sharma, Raj Kishore; Goswami, Debabrata; Sarkar, Sabyasachi; Das, Mainak

    2013-01-01

    In this work, we synthesized graphene oxide from silk cocoon embarking its new dimension as a magnetic fluorophore when compared with its present technical status, which at best is for extracting silk as a biomaterial for tissue engineering applications. We produced graphene oxide by pyrolysing the silk cocoon in an inert atmosphere. The collected raw carbon is oxidized by nitric acid that readily produces multilayer graphene oxide with nano carbon particulates. Structural properties of the g...

  1. Physico-chemical study of flavonoids from different matureness corn silk material

    OpenAIRE

    Li, Peng; Lapčík, Lubomír; Lapčíková, Barbora; Kalytchuk, Sergii

    2018-01-01

    There was tested a simple extraction procedure of flavonoids separation from the original corn silk (CS) material. It was found, that the total flavonoids content differs with the extraction time and extraction temperature. There were found different flavonoids contents in extracts prepared from different maturity stages of the original corn silk material (silking stage (CS-S), milky stage (CS-M)). Extracted flavonoids content was quantified by the lutin standardization method by means of col...

  2. Evaluating drug trafficking on the Tor Network: Silk Road 2, the sequel.

    Science.gov (United States)

    Dolliver, Diana S

    2015-11-01

    Housing an illicit, online drug retail market generating sales in the millions of USD, the Silk Road was a profitable marketplace with a growing and loyal consumer base. Following its FBI-forced shut down in October 2013, the Silk Road enjoyed newfound fame that contributed to an increase in new users downloading and accessing the Tor Network; however, with this particular marketplace out of order, Silk Road 2 was launched to fill the void. The goals of this study were to (1) compare the metrics of Silk Road 2 to the original site, and to (2) determine if there were any indications of the presence of more sophisticated drug trafficking operations. Data were collected from Silk Road 2 during the months of August and September 2014 using webcrawling software. Silk Road 2 was a much smaller marketplace than the original Silk Road. Of the 1834 unique items for sale, 348 were drug items sold by 145 distinct vendors shipping from 19 countries. Of the drug items advertised, most were stimulants and hallucinogens. The United States is both the number one country of origin for drug sales on Silk Road 2 and the number one destination country. Interestingly, 73% of all vendor accounts on Silk Road 2 advertised drug items, even though drugs only constituted 19% of all items advertised. This study was the first to research Silk Road 2, the replacement illicit marketplace to the original virtual Silk Road. This study was also the first to examine indications of the presence of more coordinated drug trafficking efforts in an online setting. The findings indicated that while Silk Road 2 was not primarily a drug market, there were indications that some vendor accounts may have connections reaching beyond a base retail market. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits

    OpenAIRE

    Christine Radtke

    2016-01-01

    Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropo...

  4. Scanning electron microscopy of the four larval instars of the Dengue fever vector Aedes aegypti (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Stefan Schaper

    2006-09-01

    Full Text Available Aedes aegypti is the main insect vector of Dengue fever and dengue hemorrhagic fever/dengue shock syndrome and represents the only vulnerable element in the control of this disease. Therefore, the identification and quantification of this mosquito is an important task; however, the majority of taxonomic keys are based on the 4th larval instar. For that reason, this study describes the four larval instars of A. aegypti using scanning electron microscopy. Morphological changes during larval development were observed at the pecten, comb scales and the ventral brush of the abdominal segment X; however, the 3rd and 4th instars showed similar structures with only a slight variation. The structures described in this study will be helpful in the identification of the four instars of A. aegypti, a fundamental task for comprehending the natural history of dengue mainly in new territories affected. Rev. Biol. Trop. 54 (3: 847-852. Epub 2006 Sept. 29.Aedes aegypti es el principal insecto vector de la fiebre del dengue y del dengue hemorrágico/síndrome del choque por dengue y es el único elemento atacable para el control de esta virosis. La identificación y cuantificación de éste es una tarea importante; no obstante, la mayoría de las llaves taxonómicas se basan en el cuarto estadio larval. Por esta razón, en este trabajo se describen los cuatro estadios larvales de A. aegypti los cuales fueron examinados mediante microscopia electrónica de rastreo. Los cambios morfológicos ocurridos durante el desarrollo larval fueron observados en el pecten, las escamas del peine, el cepillo ventral del décimo segmento. El 3ero y 4to estadios larvales mostraron estructuras similares con sólo ligeras variaciones. Las estructuras descritas en este artículo permiten identificar cualquiera de los cuatro estadios larvales de A. aegypti, lo cual representa una tarea importante en la comprensión de la historia natural del dengue en los nuevos territorios afectados.

  5. The first instar larva of two species of Miltogramminae (Diptera: Sarcophagidae) from the Middle East - examples of peculiar morphology

    DEFF Research Database (Denmark)

    Szpila, Krzysztof; Pape, Thomas

    2017-01-01

    species of Miltogramma and shares larval synapomorphies with species representing the subgenera Anacanthothecum Rohdendorf, Cylindrothecum Rohdendorf and Miltogrammidium Rohdendorf. Unique character states of the first instar larva of this species are the spine-like shape of antennal complex, laterally...... compressed apical part of mouthhooks and an extreme elongation of the sensilla of the maxillary palpus. Phrosinella (Asiometopa) ujgura (Rohdendorf) possesses a pair of retractable, robust processes on the ventral margin of the first thoracic segment and a very strong, elongated labrum. Both character states...

  6. Scanning electron microscopy of third-instar sarcophagid (Diptera: Sarcophagidae recovered from a mummified human corpse in Thailand

    Directory of Open Access Journals (Sweden)

    Sukontason Kom

    2003-01-01

    Full Text Available The third-instar of an unidentified sarcophagid, recovered from a mummified body of a 32-yr-old Thai male was examined using scanning electron microscopy (SEM. Although the morphological features of this larva are similar to the other sarcophagid larvae, some features could be helpful for species identification, which is a basic requirement for estimation of postmortem interval in forensic investigation. These features included number and arrangement of papillae on the anterior spiracle, structure of spines, size of circumspiracular tubercles at caudal segment and branching peculiarity of the posterior spiracular hairs. This information could benefit future identification of the sarcophagid larvae that exist in Thailand.

  7. Blood sampling from adrenal gland vein

    International Nuclear Information System (INIS)

    Sun Yong; Ni Caifang

    2009-01-01

    Adrenal gland vein sampling is an interventional method to get the blood samples from the adrenal gland vein. The blood is obtained via a catheter which is selectively inserted in the adrenal gland vein. This technique is mainly used to be diagnostic for primary hyperaldosteronism. A full knowledge of the anatomy and variations of the adrenal gland vein, serious preoperative preparation and skilled catheterization manipulation are necessary for obtaining sufficient blood sample and for reducing the occurrence of complications. Providing the physicians with definite diagnostic evidence and being technically feasible, adrenal gland vein sampling should become one of the routine examinations for clarifying the cause of primary hyperaldosteronism. (authors)

  8. Silk Composite with a Fluoropolymer as a Water-Resistant Protein-Based Material

    Directory of Open Access Journals (Sweden)

    Keiji Numata

    2018-04-01

    Full Text Available Silk-based materials are water-sensitive and show different physical properties at different humidities and under wet/dry conditions. To overcome the water sensitivity of silk-based materials, we developed a silk composite material with a fluoropolymer. Blending and coating the silk protein-based materials, such as films and textiles, with the fluoropolymer enhanced the surface hydrophobicity, water vapor barrier properties, and size stability during shrinkage tests. This material design with a protein biopolymer and a fluoropolymer is expected to broaden the applicability of protein-based materials.

  9. Flame retardancy and ultraviolet resistance of silk fabric coated by graphene oxide

    Directory of Open Access Journals (Sweden)

    Ji Yi-Min

    2017-01-01

    Full Text Available Silk fabrics were coated by graphene oxide hydrosol in order to improve its flame retardancy and ultraviolet resistance. In addition, montmorillonoid was doped into the graphene oxide hydrosol to further improve the flame retardancy of silk fabrics. The flame retardancy and ultraviolet resistance were mainly characterized by limiting oxygen index, vertical flame test, smoke density test, and ultraviolet protection factor. The synergistic effect of graphene oxide and montmorillonoid on the thermal stabilization property of the treated silk fabrics was also investigated. The results show that the treated silk fabrics have excellent flame retardancy, thermal stability, smoke suppression, and ultraviolet resistance simultaneously.

  10. Nutritional compositions and antioxidative capacity of the silk obtained from immature and mature corn

    Directory of Open Access Journals (Sweden)

    Nurhanan Abdul Rahman

    2014-04-01

    Full Text Available The silks of immature and mature corn were evaluated for their variations in nutritional compositions, mineral content and antioxidant capacity. Both immature and mature silks were good source of nutritional compositions. Immature silks contained significantly higher moisture (89.31% (fresh basis, lipid (1.27% and protein (12.96% content than the mature silk. Mature silks contained higher composition of ash (5.51%, carbohydrate (29.74% and total dietary fiber (51.25 g/100 g, than the immature silk, but the difference was not significant. In mineral determination, immature silk was rich source of Ca (1087.08 μg/g, Mg (1219.17 μg/g, Cu (5.60 μg/g and Zn (46.37 μg/g than the mature silks. In contrast, other minerals such as K (35671.67 μg/g, Na (266.67 μg/g, Fe (4.50 μg/g and Mn (35.57 μg/g were found higher in the mature silk. The silks were extracted with ethyl acetate, ethanol and water using the Soxhlet extraction method to determine the polyphenol and ABTS radical scavenging capacity. From this study, the highest content of total polyphenol of immature silks was exhibited by ethanol extract (92.21 mg GAE/g while water extract (64.22 mg GAE/g had the highest polyphenol content among mature silk extracts. Total flavonoid content of both immature and mature silks was higher in the water extract at 8.40 mg CAE/g and 2.31 mg CAE/g, respectively. In the ABTS free radical assay method, all immature silk extracts had higher percentage of inhibition compared to the mature silks. Among all three crude extracts, the ethanol extract of immature (EC50 = 0.478 mg/ml and mature silk (EC50 = 0.799 mg/ml exhibited the strongest antioxidant capacity followed by the water and ethyl acetate extract.

  11. A highly divergent gene cluster in honey bees encodes a novel silk family

    OpenAIRE

    Sutherland, Tara D.; Campbell, Peter M.; Weisman, Sarah; Trueman, Holly E.; Sriskantha, Alagacone; Wanjura, Wolfgang J.; Haritos, Victoria S.

    2006-01-01

    The pupal cocoon of the domesticated silk moth Bombyx mori is the best known and most extensively studied insect silk. It is not widely known that Apis mellifera larvae also produce silk. We have used a combination of genomic and proteomic techniques to identify four honey bee fiber genes (AmelFibroin1–4) and two silk-associated genes (AmelSA1 and 2). The four fiber genes are small, comprise a single exon each, and are clustered on a short genomic region where the open reading frames are GC-r...

  12. Biobased silver nanocolloid coating on silk fibers for prevention of post-surgical wound infections

    Directory of Open Access Journals (Sweden)

    Dhas SP

    2015-10-01

    Full Text Available Sindhu Priya Dhas, Suruthi Anbarasan, Amitava Mukherjee, Natarajan Chandrasekaran Center for Nanobiotechnology, VIT University, Vellore, India Abstract: Bombyx mori silk fibers are an important biomaterial and are used in surgical sutures due to their remarkable biocompatibility. The major drawback to the application of biomaterials is the risk of bacterial invasion, leading to clinical complications. We have developed an easy and cost-effective method for fabrication of antibacterial silk fibers loaded with silver nanoparticles (AgNPs by an in situ and ex situ process using an aqueous extract of Rhizophora apiculata leaf. Scanning electron microscopy revealed that well dispersed nanoparticles impregnated the silk fibers both in situ and ex situ. The crystalline nature of the AgNPs in the silk fibers was demonstrated by X-ray diffraction. The thermal and mechanical properties of the silk fibers were enhanced after they were impregnated with AgNPs. The silver-coated silk fibers fabricated by the in situ and ex situ method exhibited more than 90% inhibition against Pseudomonas aeruginosa and Staphylococcus aureus. Silk fibers doped with AgNPs were found to be biocompatible with 3T3 fibroblasts. The results obtained represent an important advance towards the clinical application of biocompatible AgNP-loaded silk fibers for prevention of surgical wound infections. Keywords: silk fibers, silver nanoparticles, antibacterial activity, wound infections, cytotoxicity, 3T3 fibroblast cells

  13. Structural and thermal properties of silk fibroin - Silver nanoparticles composite films

    Science.gov (United States)

    Shivananda, C. S.; Rao B, B. Lakshmeesha; Shetty, G. Rajesh; Sangappa, Y.

    2018-05-01

    In this work, silk fibroin-silver nanoparticles (SF-AgNPs) composite films have been prepared by simple solution casting method. The composite films were examined for structural and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results showed that with the introduction of AgNPs in the silk fibroin matrix the amorphous nature of the silk fibroin decreases with increasing nanoparticles concentration. The silk fibroin films possess good thermal stability with the presence of AgNPs.

  14. Radiation processing of silk protein (Bilateral research cooperation OAEP and JAERI. December 1998 - December 2002)

    International Nuclear Information System (INIS)

    2003-01-01

    Thailand's production of silk, about 1,200 ton per year, also gives about 10% of silk waste which is expected to be recycled into new material (non-textile application) and to avoid environmental pollution. For this purpose, cooperative program 'radiation processing of silk protein' was conducted between OAEP (Thailand) and JAERI. Among the results already obtained are: radiation degradation of silk protein (fibroin) with gamma rays at 160 kGy, production of fine silk milled powder (<90 microns) by electron beam irradiation at 250-1000 kGy (dry method) using electron accelerator (1 MeV, 1 mA), use of antioxidant effect of silk protein on lipid peroxidation and antibacterial activity of irradiated silk protein powder, and wound dressing hydrogel mixed with silk protein and use of antibacterial activity of cross-linked silk protein/PVA hydrogel. Other topics of interest are gamma irradiation of anionic natural polymer solution for use as latex protein scavenger and gamma radiation degradation of chitosan for use as plant growth promoter and fungicide. (S. Ohno)

  15. Silk fibroin-chondroitin sulfate scaffold with immuno-inhibition property for articular cartilage repair.

    Science.gov (United States)

    Zhou, Feifei; Zhang, Xianzhu; Cai, Dandan; Li, Jun; Mu, Qin; Zhang, Wei; Zhu, Shouan; Jiang, Yangzi; Shen, Weiliang; Zhang, Shufang; Ouyang, Hong Wei

    2017-11-01

    The demand of favorable scaffolds has increased for the emerging cartilage tissue engineering. Chondroitin sulfate (CS) and silk fibroin have been investigated and reported with safety and excellent biocompatibility as tissue engineering scaffolds. However, the rapid degradation rate of pure CS scaffolds presents a challenge to effectively recreate neo-tissue similar to natural articular cartilage. Meanwhile the silk fibroin is well used as a structural constituent material because its remarkable mechanical properties, long-lasting in vivo stability and hypoimmunity. The application of composite silk fibroin and CS scaffolds for joint cartilage repair has not been well studied. Here we report that the combination of silk fibroin and CS could synergistically promote articular cartilage defect repair. The silk fibroin (silk) and silk fibroin/CS (silk-CS) scaffolds were fabricated with salt-leaching, freeze-drying and crosslinking methodologies. The biocompatibility of the scaffolds was investigated in vitro by cell adhesion, proliferation and migration with human articular chondrocytes. We found that silk-CS scaffold maintained better chondrocyte phenotype than silk scaffold; moreover, the silk-CS scaffolds reduced chondrocyte inflammatory response that was induced by interleukin (IL)-1β, which is in consistent with the well-documented anti-inflammatory activities of CS. The in vivo cartilage repair was evaluated with a rabbit osteochondral defect model. Silk-CS scaffold induced more neo-tissue formation and better structural restoration than silk scaffold after 6 and 12weeks of implantation in ICRS histological evaluations. In conclusion, we have developed a silk fibroin/ chondroitin sulfate scaffold for cartilage tissue engineering that exhibits immuno-inhibition property and can improve the self-repair capacity of cartilage. Severe cartilage defect such as osteoarthritis (OA) is difficult to self-repair because of its avascular, aneural and alymphatic nature

  16. Development of an enzyme-linked-immunosorbent-assay technique for accurate identification of poorly preserved silks unearthed in ancient tombs.

    Science.gov (United States)

    Zheng, Qin; Wu, Xiaofeng; Zheng, Hailing; Zhou, Yang

    2015-05-01

    We report the preparation of a specific fibroin antibody and its use for the identification of unearthed ancient silk relics. Based on the 12-amino-acid repeat sequence "GAGAGSGAGAGS", which is found in fibroin of the silkworm Bombyx mori, a specific antibody against fibroin was prepared in rabbits through peptide synthesis and carrier-protein coupling. This antibody was highly specific for fibroin found in silk. Using this antibody we have successfully identified four silk samples from different time periods. Our results reveal, for the first time, a method capable of detecting silk from a few milligrams of archaeological fabric that has been buried for thousands of years, confirming that the ancient practice of wearing silk products while praying for rebirth dated back to at least 400 BCE. This method also complements current approaches in silk detection, especially for the characterization of poorly preserved silks, promoting the investigation of silk origins and of ancient clothing cultures.

  17. Submandibular gland function and parotid gland function in Bell's palsy, 3

    International Nuclear Information System (INIS)

    Ino, Chiyonori; Yamashita, Toshio; Kato, Mako; Kumazawa, Tadami

    1986-01-01

    With the use of sup(99m)Tc, we attempted to measure simultaneously submandibular gland function and parotid gland function, which is thought not to be controlled by the facial nerve, in patients with unilateral Bell's palsy. For comparison, the lachrymal gland function of some patients was measured by the thread method. We found that facial palsy sometimes affects parotid gland function as well as submandibular gland function. In 60 % of the patients the function of the two glands tended to be affected in the same way. Lachrymal gland function tended to be affected in a similar way to parotid gland function. We conclude that the chorda tympani and the greater petrosal nerve may influence parotid gland function. (author)

  18. Pituitary gland development: an update.

    Science.gov (United States)

    Bancalari, Rodrigo E; Gregory, Louise C; McCabe, Mark J; Dattani, Mehul T

    2012-01-01

    The embryonic development of the pituitary gland involves a complex and highly spatio-temporally regulated network of integrating signalling molecules and transcription factors. Genetic mutations in any of these factors can lead to congenital hypopituitarism in association with a wide spectrum of craniofacial/midline defects ranging from incompatibility with life to holoprosencephaly (HPE) and cleft palate and septo-optic dysplasia (SOD). Increasing evidence supports a genotypic overlap with hypogonadotrophic hypogonadal disorders such as Kallmann syndrome, which is consistent with the known overlap in phenotypes between these disorders. This chapter reviews the cascade of events leading up to the successful development of the pituitary gland and to highlight key areas where genetic variations can occur thus leading to congenital hypopituitarism and associated defects. Copyright © 2012 S. Karger AG, Basel.

  19. Silk Film Topography Directs Collective Epithelial Cell Migration

    Science.gov (United States)

    Rosenblatt, Mark I.

    2012-01-01

    The following study provides new insight into how surface topography dictates directed collective epithelial cell sheet growth through the guidance of individual cell movement. Collective cell behavior of migrating human corneal limbal-epithelial cell sheets were studied on highly biocompatible flat and micro-patterned silk film surfaces. The silk film edge topography guided the migratory direction of individual cells making up the collective epithelial sheet, which resulted in a 75% increase in total culture elongation. This was due to a 3-fold decrease in cell sheet migration rate efficiency for movement perpendicular to the topography edge. Individual cell migration direction is preferred in the parallel approach to the edge topography where localization of cytoskeletal proteins to the topography’s edge region is reduced, which results in the directed growth of the collective epithelial sheet. Findings indicate customized biomaterial surfaces may be created to direct both the migration rate and direction of tissue epithelialization. PMID:23185573

  20. SILK ROAD DISEASE: FROM LEGENDS TO THE 21st CENTURY

    Directory of Open Access Journals (Sweden)

    Z. S. Alekberova

    2015-01-01

    Full Text Available The paper considers the historical and geographical aspects of Behcet’s disease (BD. As is known, the geographical distribution of this disease is associated with the ancient caravan route called the Silk Road: it was in these areas along which the latter once ran there have been predominantly cases of BD so far. There are discrepancies in the literature regarding whether the Silk Road was across the North Caucasus, along the coast of the Caspian Sea in particular. In support of this conjecture, there is interesting evidence: stone-cutting images that have been retained on the houses of the Dagestani settlement of Kubachi. All give an answer why the natives of the North Caucasus constitute one-fourth of the total number of BD patients followed up at the V.A. Nasonova Research Institute of Rheumatology 

  1. Peculiar torsion dynamical response of spider dragline silk

    Science.gov (United States)

    Liu, Dabiao; Yu, Longteng; He, Yuming; Peng, Kai; Liu, Jie; Guan, Juan; Dunstan, D. J.

    2017-07-01

    The torsional properties of spider dragline silks from Nephila edulis and Nephila pilipes spiders are investigated by using a torsion pendulum technique. A permanent torsional deformation is observed after even small torsional strain. This behaviour is quite different from that of the other materials tested here, i.e., carbon fiber, thin metallic wires, Kevlar fiber, and human hair. The spider dragline thus displays a strong energy dissipation upon the initial excitation (around 75% for small strains and more for a larger strain), which correspondingly reduces the amplitude of subsequent oscillations around the new equilibrium position. The variation of torsional stiffness in relaxation dynamics of spider draglines for different excitations is also determined. The experimental result is interpreted in the light of the hierarchical structure of dragline silk.

  2. Prognosis and submandibular gland function

    International Nuclear Information System (INIS)

    Ino, Chiyonori; Yamashita, Toshio; Hanaoka, Mako; Kumazawa, Tadami

    1984-01-01

    Submandibular gland function was tested with sup(99m)Tc-pertechnetate scan 10 days and 3-4 weeks after the onset Bell's palsy, and the results and prognoses were correlated. In the first report we divided the cases into groups A, B and C, and this time group D classified in S.S.R. was poor. Groups A and D can be differentiated by submandibular gland scan within 10 days after the onset; that is to say, the prognosis of more than half the cases can be determined in this early phase. Especially, it is noticeable that group D showing the poor prognosis is differentiated within 10 days after the onset. This method was compared with other tests of facial palsy. Four to five weeks after the onset all tests were of equal accuracy in predicting the prognosis of each group. Within 10 days after the onset, however, submandibular gland scan seems to be more useful than the other tests. (author)

  3. Low pressure-induced secondary structure transitions of regenerated silk fibroin in its wet film studied by time-resolved infrared spectroscopy.

    Science.gov (United States)

    He, Zhipeng; Liu, Zhao; Zhou, Xiaofeng; Huang, He

    2018-06-01

    The secondary structure transitions of regenerated silk fibroin (RSF) under different external perturbations have been studied extensively, except for pressure. In this work, time-resolved infrared spectroscopy with the attenuated total reflectance (ATR) accessory was employed to follow the secondary structure transitions of RSF in its wet film under low pressure. It has been found that pressure alone is favorable only to the formation of β-sheet structure. Under constant pressure there is an optimum amount of D 2 O in the wet film (D 2 O : film = 2:1) so as to provide the optimal condition for the reorganization of the secondary structure and to have the largest formation of β-sheet structure. Under constant amount of D 2 O and constant pressure, the secondary structure transitions of RSF in its wet film can be divided into three stages along with time. In the first stage, random coil, α-helix, and β-turn were quickly transformed into β-sheet. In the second stage, random coil and β-turn were relatively slowly transformed into β-sheet and α-helix, and the content of α-helix was recovered to the value prior to the application of pressure. In the third and final stage, no measurable changes can be found for each secondary structure. This study may be helpful to understand the secondary structure changes of silk fibroin in silkworm's glands under hydrostatic pressure. © 2018 Wiley Periodicals, Inc.

  4. Ultra-high Thermal Conductivity of Spider Silk: Protein Function Study with Controlled Structure Change and Comparison

    Science.gov (United States)

    2016-01-23

    induced increase in energy transport capacity of silkworm silks , Biopolymers , (10 2014): 0. doi: 10.1002/bip.22496 Shen Xu, Zaoli Xu, James Starrett...SECURITY CLASSIFICATION OF: In the past three years, we have conducted extensive research to study the structure of spider silks and investigate how the...manually spun spider silks demonstrates that the alignment of the antiparallel beta-sheet crystals in spider silks plays one of the most important

  5. An Understanding of The Maritime Silk Road International Strategic Importance

    Institute of Scientific and Technical Information of China (English)

    Lin; Hongyu

    2015-01-01

    "The Maritime Silk Road"conception has a very significant international strategic importance,and to China,will certainly play a great role in promoting its economic development,which is only on the surface,and an in-depth reading is that it is a top-level strategic design,whose strategic role with the passage of time will be enlarged.In his address to Indonesian National Assembly in October 2013,President Xi

  6. Silk fibroin gelation via non-solvent induced phase separation

    Czech Academy of Sciences Publication Activity Database

    Kasoju, Naresh; Hawkins, N.; Pop-Georgievski, Ognen; Kubies, Dana; Vollrath, F.

    2016-01-01

    Roč. 4, č. 3 (2016), s. 460-473 ISSN 2047-4830 R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : silk fibroin * non-solvent induced phase separation * desolvation Subject RIV: CE - Biochemistry Impact factor: 4.210, year: 2016

  7. Unique molecular architecture of silk fibroin in the waxmoth

    Czech Academy of Sciences Publication Activity Database

    Žurovec, Michal; Sehnal, František

    2002-01-01

    Roč. 277, č. 25 (2002), s. 22639-22647 ISSN 0021-9258 R&D Projects: GA ČR GA204/96/1100; GA ČR GA204/00/0019; GA MŠk ME 204 Institutional research plan: CEZ:AV0Z5007907 Keywords : silk Subject RIV: EG - Zoology Impact factor: 6.696, year: 2002

  8. Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

    Science.gov (United States)

    Zhang, Yu-Qing; Shen, Wei-De; Xiang, Ru-Li; Zhuge, Lan-Jian; Gao, Wei-Jian; Wang, Wen-Bao

    2007-10-01

    When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl2, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the ɛ-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and α-helix form (Silk I) into anti-parallel β-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, 13C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with β-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular substructure of the degraded silk

  9. Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

    International Nuclear Information System (INIS)

    Zhang Yuqing; Shen Weide; Xiang Ruli; Zhuge Lanjian; Gao Weijian; Wang Wenbao

    2007-01-01

    When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl 2 , the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the ε-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and α-helix form (Silk I) into anti-parallel β-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, 13 C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with β-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular substructure of the degraded silk

  10. Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yuqing, E-mail: yqzhang@public1.sz.js.cn; Shen Weide; Xiang Ruli [Soochow University, Silk Biotechnol. Lab., School of Life Science (China); Zhuge Lanjian; Gao Weijian; Wang Wenbao [Soochow University, Analytical Center (China)

    2007-10-15

    When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl{sub 2}, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the {epsilon}-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and {alpha}-helix form (Silk I) into anti-parallel {beta}-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, {sup 13}C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with {beta}-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular

  11. Web building and silk properties functionally covary among species of wolf spider.

    Science.gov (United States)

    Lacava, Mariángeles; Camargo, Arley; Garcia, Luis F; Benamú, Marco A; Santana, Martin; Fang, Jian; Wang, Xungai; Blamires, Sean J

    2018-04-15

    Although phylogenetic studies have shown covariation between the properties of spider major ampullate (MA) silk and web building, both spider webs and silks are highly plastic so we cannot be sure whether these traits functionally covary or just vary across environments that the spiders occupy. As MaSp2-like proteins provide MA silk with greater extensibility, their presence is considered necessary for spider webs to effectively capture prey. Wolf spiders (Lycosidae) are predominantly non-web building, but a select few species build webs. We accordingly collected MA silk from two web-building and six non-web-building species found in semirural ecosystems in Uruguay to test whether the presence of MaSp2-like proteins (indicated by amino acid composition, silk mechanical properties and silk nanostructures) was associated with web building across the group. The web-building and non-web-building species were from disparate subfamilies so we estimated a genetic phylogeny to perform appropriate comparisons. For all of the properties measured, we found differences between web-building and non-web-building species. A phylogenetic regression model confirmed that web building and not phylogenetic inertia influences silk properties. Our study definitively showed an ecological influence over spider silk properties. We expect that the presence of the MaSp2-like proteins and the subsequent nanostructures improves the mechanical performance of silks within the webs. Our study furthers our understanding of spider web and silk co-evolution and the ecological implications of spider silk properties. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology.

  12. Gel spinning of silk tubes for tissue engineering

    Science.gov (United States)

    Lovett, Michael; Cannizzaro, Christopher; Vunjak-Novakovic, Gordana; Kaplan, David L.

    2011-01-01

    Tubular vessels for tissue engineering are typically fabricated using a molding, dipping, or electrospinning technique. While these techniques provide some control over inner and outer diameters of the tube, they lack the ability to align the polymers or fibers of interest throughout the tube. This is an important aspect of biomaterial composite structure and function for mechanical and biological impact of tissue outcomes. We present a novel aqueous process system to spin tubes from biopolymers and proteins such as silk fibroin. Using silk as an example, this method of winding an aqueous solution around a reciprocating rotating mandrel offers substantial improvement in the control of the tube properties, specifically with regard to winding pattern, tube porosity, and composite features. Silk tube properties are further controlled via different post-spinning processing mechanisms such as methanol-treatment, air-drying, and lyophilization. This approach to tubular scaffold manufacture offers numerous tissue engineering applications such as complex composite biomaterial matrices, blood vessel grafts and nerve guides, among others. PMID:18801570

  13. Silk Fibroin Degradation Related to Rheological and Mechanical Properties.

    Science.gov (United States)

    Partlow, Benjamin P; Tabatabai, A Pasha; Leisk, Gary G; Cebe, Peggy; Blair, Daniel L; Kaplan, David L

    2016-05-01

    Regenerated silk fibroin has been proposed as a material substrate for biomedical, optical, and electronic applications. Preparation of the silk fibroin solution requires extraction (degumming) to remove contaminants, but results in the degradation of the fibroin protein. Here, a mechanism of fibroin degradation is proposed and the molecular weight and polydispersity is characterized as a function of extraction time. Rheological analysis reveals significant changes in the viscosity of samples while mechanical characterization of cast and drawn films shows increased moduli, extensibility, and strength upon drawing. Fifteen minutes extraction time results in degraded fibroin that generates the strongest films. Structural analysis by wide angle X-ray scattering (WAXS) and Fourier transform infrared spectroscopy (FTIR) indicates molecular alignment in the drawn films and shows that the drawing process converts amorphous films into the crystalline, β-sheet, secondary structure. Most interesting, by using selected extraction times, films with near-native crystallinity, alignment, and molecular weight can be achieved; yet maximal mechanical properties for the films from regenerated silk fibroin solutions are found with solutions subjected to some degree of degradation. These results suggest that the regenerated solutions and the film casting and drawing processes introduce more complexity than native spinning processes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Fabrication and Mechanical Characterization of Hydrogel Infused Network Silk Scaffolds

    Directory of Open Access Journals (Sweden)

    Lakshminath Kundanati

    2016-09-01

    Full Text Available Development and characterization of porous scaffolds for tissue engineering and regenerative medicine is of great importance. In recent times, silk scaffolds were developed and successfully tested in tissue engineering and drug release applications. We developed a novel composite scaffold by mechanical infusion of silk hydrogel matrix into a highly porous network silk scaffold. The mechanical behaviour of these scaffolds was thoroughly examined for their possible use in load bearing applications. Firstly, unconfined compression experiments show that the denser composite scaffolds displayed significant enhancement in the elastic modulus as compared to either of the components. This effect was examined and further explained with the help of foam mechanics principles. Secondly, results from confined compression experiments that resemble loading of cartilage in confinement, showed nonlinear material responses for all scaffolds. Finally, the confined creep experiments were performed to calculate the hydraulic permeability of the scaffolds using soil mechanics principles. Our results show that composite scaffolds with some modifications can be a potential candidate for use of cartilage like applications. We hope such approaches help in developing novel scaffolds for tissue engineering by providing an understanding of the mechanics and can further be used to develop graded scaffolds by targeted infusion in specific regions.

  15. Study on antibacterial activity of hydrogel from irradiated silk protein

    International Nuclear Information System (INIS)

    Bunnak, J.; Chaisupakitsin, M.

    2001-01-01

    Hydrogels for biomedical application were prepared from solution blends of 3% silk protein and 3%, 10% poly (vinyl alcohol) (PVA) and followed with irradiation. Mixture of hydrogels were gamma irradiated at 10, 20, 30, 40 and 50 kGy under N 2 atmosphere. To clarify anti-bacterial activity of hydrogels, modified of the Agar disk diffusion method and American Association of Textile Chemists and Colorists, AATCC Test Method 90-1977, were carried out. The four kinds of bacteria such as Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis, were used. It was found that a 1:3 volume ratio of 3% silk protein and 3% PVA respectively, at 50 kGy irradiation, is suitable conditions for preparation hydrogels and trend to indicate the highest of an antibacterial activity against E. coli, B. subtilis and S. aureus. However the antibacterial activity of hydrogels against S. epidermidis was not clearly. These results are very useful to expand the application of hydrogel from irradiated silk protein to the medical products. (author)

  16. Anisotropic silk fibroin/gelatin scaffolds from unidirectional freezing

    Energy Technology Data Exchange (ETDEWEB)

    Asuncion, Maria Christine Tankeh, E-mail: christine.asuncion@u.nus.edu [National University of Singapore, Department of Biomedical Engineering (Singapore); Goh, James Cho-Hong [National University of Singapore, Department of Biomedical Engineering (Singapore); National University of Singapore, Department of Orthopedic Surgery (Singapore); Toh, Siew-Lok [National University of Singapore, Department of Biomedical Engineering (Singapore); National University of Singapore, Department of Mechanical Engineering (Singapore)

    2016-10-01

    Recent studies have underlined the importance of matching scaffold properties to the biological milieu. Tissue, and thus scaffold, anisotropy is one such property that is important yet sometimes overlooked. Methods that have been used to achieve anisotropic scaffolds present challenges such as complicated fabrication steps, harsh processing conditions and toxic chemicals involved. In this study, unidirectional freezing was employed to fabricate anisotropic silk fibroin/gelatin scaffolds in a simple and mild manner. Morphological, mechanical, chemical and cellular compatibility properties were investigated, as well as the effect of the addition of gelatin to certain properties of the scaffold. It was shown that scaffold properties were suitable for cell proliferation and that mesenchymal stem cells were able to align themselves along the directed fibers. The fabricated scaffolds present a platform that can be used for anisotropic tissue engineering applications such as cardiac patches. - Highlights: • Silk/gelatin scaffolds with unidirectional alignment were fabricated using a simple and scalable process • Presence of gelatin in silk resulted to lesser shrinkage, better water retention and improved cell proliferation. • Mesenchymal stem cells were shown to align themselves according to the fiber alignment.

  17. Interfacial Shear Strength and Adhesive Behavior of Silk Ionomer Surfaces.

    Science.gov (United States)

    Kim, Sunghan; Geryak, Ren D; Zhang, Shuaidi; Ma, Ruilong; Calabrese, Rossella; Kaplan, David L; Tsukruk, Vladimir V

    2017-09-11

    The interfacial shear strength between different layers in multilayered structures of layer-by-layer (LbL) microcapsules is a crucial mechanical property to ensure their robustness. In this work, we investigated the interfacial shear strength of modified silk fibroin ionomers utilized in LbL shells, an ionic-cationic pair with complementary ionic pairing, (SF)-poly-l-glutamic acid (Glu) and SF-poly-l-lysine (Lys), and a complementary pair with partially screened Coulombic interactions due to the presence of poly(ethylene glycol) (PEG) segments and SF-Glu/SF-Lys[PEG] pair. Shearing and adhesive behavior between these silk ionomer surfaces in the swollen state were probed at different spatial scales and pressure ranges by using functionalized atomic force microscopy (AFM) tips as well as functionalized colloidal probes. The results show that both approaches were consistent in analyzing the interfacial shear strength of LbL silk ionomers at different spatial scales from a nanoscale to a fraction of a micron. Surprisingly, the interfacial shear strength between SF-Glu and SF-Lys[PEG] pair with partially screened ionic pairing was greater than the interfacial shear strength of the SF-Glu and SF-Lys pair with a high density of complementary ionic groups. The difference in interfacial shear strength and adhesive strength is suggested to be predominantly facilitated by the interlayer hydrogen bonding of complementary amino acids and overlap of highly swollen PEG segments.

  18. Processing Techniques and Applications of Silk Hydrogels in Bioengineering

    Directory of Open Access Journals (Sweden)

    Michael Floren

    2016-09-01

    Full Text Available Hydrogels are an attractive class of tunable material platforms that, combined with their structural and functional likeness to biological environments, have a diversity of applications in bioengineering. Several polymers, natural and synthetic, can be used, the material selection being based on the required functional characteristics of the prepared hydrogels. Silk fibroin (SF is an attractive natural polymer for its excellent processability, biocompatibility, controlled degradation, mechanical properties and tunable formats and a good candidate for the fabrication of hydrogels. Tremendous effort has been made to control the structural and functional characteristic of silk hydrogels, integrating novel biological features with advanced processing techniques, to develop the next generation of functional SF hydrogels. Here, we review the several processing methods developed to prepare advanced SF hydrogel formats, emphasizing a bottom-up approach beginning with critical structural characteristics of silk proteins and their behavior under specific gelation environments. Additionally, the preparation of SF hydrogel blends and other advanced formats will also be discussed. We conclude with a brief description of the attractive utility of SF hydrogels in relevant bioengineering applications.

  19. Study on antibacterial activity of hydrogel from irradiated silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Bunnak, J; Chaisupakitsin, M [King Mongkut' s Institute of Technology Lardkrabang, Bangkok (Thailand)

    2001-03-01

    Hydrogels for biomedical application were prepared from solution blends of 3% silk protein and 3%, 10% poly (vinyl alcohol) (PVA) and followed with irradiation. Mixture of hydrogels were gamma irradiated at 10, 20, 30, 40 and 50 kGy under N{sub 2} atmosphere. To clarify anti-bacterial activity of hydrogels, modified of the Agar disk diffusion method and American Association of Textile Chemists and Colorists, AATCC Test Method 90-1977, were carried out. The four kinds of bacteria such as Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis, were used. It was found that a 1:3 volume ratio of 3% silk protein and 3% PVA respectively, at 50 kGy irradiation, is suitable conditions for preparation hydrogels and trend to indicate the highest of an antibacterial activity against E. coli, B. subtilis and S. aureus. However the antibacterial activity of hydrogels against S. epidermidis was not clearly. These results are very useful to expand the application of hydrogel from irradiated silk protein to the medical products. (author)

  20. Exploring the mechanism of microarteriogenesis in porous silk fibroin film.

    Science.gov (United States)

    Bai, Lun; Wang, Guangqian; Tan, Xiaoyan; Xu, Jianmei

    2012-01-01

    Purpose. Based on the experiment of the microarteriogenesis that is associated with angiogenesis during tissue repair process in porous silk fibroin films (PSFFs), we investigate the characteristics of micro-arteriogenesis and explore its mechanism. Methods. After the porous silk fibroin materials are implanted into the back hypodermal tissue of SD rats, the arteriole development and the morphogenesis of smooth muscle cell are histologically monitored and the micro-arteriogenesis is quantitatively analyzed. Results. 10 days after implantation, the arteriole density reaches the highest level in the junction of silk fibroin materials with tissues. Three weeks later, the arteriolar density in the materials reaches the maximum, and the arterioles in the junction of materials with tissues appear to be in a mature and upgrading state. Modeling of Microarteriogenesis. The arterioles in materials are generated after capillary angiogenesis. It is inferred that arteriolar development does not start until the network of the capillaries is formed. At first, the arterioles grow in the conjunct area of precapillaries with arterioles. Then with the extension of the arterioles, the upgrade of arterioles in connecting area is observed at a later stage. Based on the observation, the conditions and the mechanism of microarterializations as well as the upgrade of arterioles are analyzed.

  1. Evaluation of the toxic potential of aspartame in third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ) Bg9

    Energy Technology Data Exchange (ETDEWEB)

    Siddique, Y.H.; Anjum, S.; Rahul x, Smita Jyoti

    2017-07-01

    Aspartame is commonly used as a sweetener in prepared foods, beverages and in recipes. In the present study the possible toxic effects of aspartame were studied in third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ) Bg9. The third instar larvae were allowed to feed on the diet having different doses of aspartame. The results obtained in the present study suggest that the exposure of third instar larvae to the diet having 20, 40, 80, 160 and 320 mM of aspartame did not show any significant the toxic effects after 24 hours of the exposure compared to control (p<0.05). The results for pupae formation and emergence of flies also did not show any significant difference compared to control (p<0.05).

  2. Evaluation of the toxic potential of aspartame in third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ Bg9

    Directory of Open Access Journals (Sweden)

    YASIR HASAN SIDDIQUE

    2017-07-01

    Full Text Available Aspartame is commonly used as a sweetener in prepared foods, beverages and in recipes. In the present study the possible toxic effects of aspartame were studied in third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ Bg9. The third instar larvae were allowed to feed on the diet having different doses of aspartame. The results obtained in the present study suggest that the exposure of third instar larvae to the diet having 20, 40, 80, 160 and 320 mM of aspartame did not show any significant the toxic effects after 24 hours of the exposure compared to control (p<0.05. The results for pupae formation and emergence of flies also did not show any significant difference compared to control (p<0.05.

  3. Evaluation of the toxic potential of aspartame in third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ) Bg9

    International Nuclear Information System (INIS)

    Siddique, Y.H.; Anjum, S.; Rahul x, Smita Jyoti

    2017-01-01

    Aspartame is commonly used as a sweetener in prepared foods, beverages and in recipes. In the present study the possible toxic effects of aspartame were studied in third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ) Bg9. The third instar larvae were allowed to feed on the diet having different doses of aspartame. The results obtained in the present study suggest that the exposure of third instar larvae to the diet having 20, 40, 80, 160 and 320 mM of aspartame did not show any significant the toxic effects after 24 hours of the exposure compared to control (p<0.05). The results for pupae formation and emergence of flies also did not show any significant difference compared to control (p<0.05).

  4. Optimization of the silk scaffold sericin removal process for retention of silk fibroin protein structure and mechanical properties

    International Nuclear Information System (INIS)

    Teh, Thomas K H; Toh, Siew-Lok; Goh, James C H

    2010-01-01

    In the process of removing sericin (degumming) from a raw silk scaffold, the fibroin structural integrity is often challenged, leading to mechanical depreciation. This study aims to identify the factors and conditions contributing to fibroin degradation during alkaline degumming and to perform an optimization study of the parameters involved to achieve preservation of fibroin structure and properties. The methodology involves degumming knitted silk scaffolds for various durations (5-90 min) and temperatures (60-100 0 C). Mechanical agitation and use of the refreshed solution during degumming are included to investigate how these factors contribute to degumming efficiency and fibroin preservation. Characterizations of silk fibroin morphology, mechanical properties and protein components are determined by scanning electron microscopy (SEM), single fiber tensile tests and gel electrophoresis (SDS-PAGE), respectively. Sericin removal is ascertained via SEM imaging and a protein fractionation method involving SDS-PAGE. The results show that fibroin fibrillation, leading to reduced mechanical integrity, is mainly caused by prolonged degumming duration. Through a series of optimization, knitted scaffolds are observed to be optimally degummed and experience negligible mechanical and structural degradation when subjected to alkaline degumming with mechanical agitation for 30 min at 100 0 C.

  5. Folding behavior of four silks of giant honey bee reflects the evolutionary conservation of aculeate silk proteins.

    Science.gov (United States)

    Maitip, Jakkrawut; Trueman, Holly E; Kaehler, Benjamin D; Huttley, Gavin A; Chantawannakul, Panuwan; Sutherland, Tara D

    2015-04-01

    Multiple gene duplication events in the precursor of the Aculeata (bees, ants, hornets) gave rise to four silk genes. Whilst these homologs encode proteins with similar amino acid composition and coiled coil structure, the retention of all four homologs implies they each are important. In this study we identified, produced and characterized the four silk proteins from Apis dorsata, the giant Asian honeybee. The proteins were readily purified, allowing us to investigate the folding behavior of solutions of individual proteins in comparison to mixtures of all four proteins at concentrations where they assemble into their native coiled coil structure. In contrast to solutions of any one protein type, solutions of a mixture of the four proteins formed coiled coils that were stable against dilution and detergent denaturation. The results are consistent with the formation of a heteromeric coiled coil protein complex. The mechanism of silk protein coiled coil formation and evolution is discussed in light of these results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Optimization of the silk scaffold sericin removal process for retention of silk fibroin protein structure and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Teh, Thomas K H; Toh, Siew-Lok; Goh, James C H, E-mail: dosgohj@nus.edu.s, E-mail: dostkh@nus.edu.s, E-mail: bietohsl@nus.edu.s [Division of Bioengineering, National University of Singapore (Singapore)

    2010-06-01

    In the process of removing sericin (degumming) from a raw silk scaffold, the fibroin structural integrity is often challenged, leading to mechanical depreciation. This study aims to identify the factors and conditions contributing to fibroin degradation during alkaline degumming and to perform an optimization study of the parameters involved to achieve preservation of fibroin structure and properties. The methodology involves degumming knitted silk scaffolds for various durations (5-90 min) and temperatures (60-100 {sup 0}C). Mechanical agitation and use of the refreshed solution during degumming are included to investigate how these factors contribute to degumming efficiency and fibroin preservation. Characterizations of silk fibroin morphology, mechanical properties and protein components are determined by scanning electron microscopy (SEM), single fiber tensile tests and gel electrophoresis (SDS-PAGE), respectively. Sericin removal is ascertained via SEM imaging and a protein fractionation method involving SDS-PAGE. The results show that fibroin fibrillation, leading to reduced mechanical integrity, is mainly caused by prolonged degumming duration. Through a series of optimization, knitted scaffolds are observed to be optimally degummed and experience negligible mechanical and structural degradation when subjected to alkaline degumming with mechanical agitation for 30 min at 100 {sup 0}C.

  7. Institutionalizing Chineseness. The legacies of Chinese commercial hegemony in the Cambodian silk industry

    NARCIS (Netherlands)

    Dahles, H.; ter Horst, J.

    2012-01-01

    The Cambodian silk weaving industry shows a remarkable pattern of ethnicised positions interlocked in processes of production and trade stretching beyond Cambodia into the Southeast Asian region and into Europe and the United States. Key commercial positions in the Cambodian silk trading networks

  8. Mechanical properties of silk of the Australian golden orb weavers Nephila pilipes and Nephilaplumipes.

    Science.gov (United States)

    Kerr, Genevieve G; Nahrung, Helen F; Wiegand, Aaron; Kristoffersen, Joanna; Killen, Peter; Brown, Cameron; Macdonald, Joanne

    2018-02-22

    Silks from orb-weaving spiders are exceptionally tough, producing a model polymer for biomimetic fibre development. The mechanical properties of naturally spun silk threads from two species of Australian orb-weavers, Nephila pilipes and Nephila plumipes , were examined here in relation to overall thread diameter, the size and number of fibres within threads, and spider size. N. pilipes , the larger of the two species, had significantly tougher silk with higher strain capacity than its smaller congener, producing threads with average toughness of 150 MJ m -3 , despite thread diameter, mean fibre diameter and number of fibres per thread not differing significantly between the two species. Within N. pilipes , smaller silk fibres were produced by larger spiders, yielding tougher threads. In contrast, while spider size was correlated with thread diameter in N. plumipes , there were no clear patterns relating to silk toughness, which suggests that the differences in properties between the silk of the two species arise through differing molecular structure. Our results support previous studies that found that the mechanical properties of silk differ between distantly related spider species, and extends on that work to show that the mechanical and physical properties of silk from more closely related species can also differ remarkably. © 2018. Published by The Company of Biologists Ltd.

  9. Feeding Single-Walled Carbon Nanotubes or Graphene to Silkworms for Reinforced Silk Fibers.

    Science.gov (United States)

    Wang, Qi; Wang, Chunya; Zhang, Mingchao; Jian, Muqiang; Zhang, Yingying

    2016-10-12

    Silkworm silk is gaining significant attention from both the textile industry and research society because of its outstanding mechanical properties and lustrous appearance. The possibility of creating tougher silks attracts particular research interest. Carbon nanotubes and graphene are widely studied for their use as reinforcement. In this work, we report mechanically enhanced silk directly collected by feeding Bombyx mori larval silkworms with single-walled carbon nanotubes (SWNTs) and graphene. We found that parts of the fed carbon nanomaterials were incorporated into the as-spun silk fibers, whereas the others went into the excrement of silkworms. Spectroscopy study indicated that nanocarbon additions hindered the conformation transition of silk fibroin from random coil and α-helix to β-sheet, which may contribute to increased elongation at break and toughness modules. We further investigated the pyrolysis of modified silk, and a highly developed graphitic structure with obviously enhanced electrical conductivity was obtained through the introduction of SWNTs and graphene. The successful generation of these SWNT- or graphene-embedded silks by in vivo feeding is expected to open up possibilities for the large-scale production of high-strength silk fibers.

  10. Energy absorption and failure response of silk/epoxy composite square tubes: Experimental

    DEFF Research Database (Denmark)

    Oshkovr, Simin Ataollahi; Taher, Siavash Talebi; A. Eshkoor, Rahim

    2012-01-01

    This paper focuses on natural silk/epoxy composite square tubes energy absorption and failure response. The tested specimens were featured by a material combination of different lengths and same numbers of natural silk/epoxy composite layers in form of reinforced woven fabric in thermosetting epoxy...

  11. Investigation of synthetic spider silk crystallinity and alignment via electrothermal, pyroelectric, literature XRD, and tensile techniques

    NARCIS (Netherlands)

    Munro, Troy; Putzeys, Tristan; Copeland, Cameron G.; Xing, Changhu; Lewis, Randolph V.; Ban, Heng; Glorieux, Christ; Wubbenhorst, Michael

    2017-01-01

    The processes used to create synthetic spider silk greatly affect the properties of the produced fibers. This paper investigates the effect of process variations during artificial spinning on the thermal and mechanical properties of the produced silk. Property values are also compared to the ones of

  12. More than a safety line: jump-stabilizing silk of salticids.

    Science.gov (United States)

    Chen, Yung-Kang; Liao, Chen-Pan; Tsai, Feng-Yueh; Chi, Kai-Jung

    2013-10-06

    Salticids are diurnal hunters known for acute vision, remarkable predatory strategies and jumping ability. Like other jumpers, they strive for stability and smooth landings. Instead of using inertia from swinging appendages or aerodynamic forces by flapping wings as in other organisms, we show that salticids use a different mechanism for in-air stability by using dragline silk, which was previously believed to function solely as a safety line. Analyses from high-speed images of jumps by the salticid Hasarius adansoni demonstrate that despite being subject to rearward pitch at take-off, spiders with dragline silk can change body orientation in the air. Instantaneous drag and silk forces calculated from kinematic data further suggest a comparable contribution to deceleration and energy dissipation, and reveal that adjustments by the spider to the silk force can reverse its body pitch for a predictable and optimal landing. Without silk, upright-landing spiders would slip or even tumble, deferring completion of landing. Thus, for salticids, dragline silk is critical for dynamic stability and prey-capture efficiency. The dynamic functioning of dragline silk revealed in this study can advance the understanding of silk's physiological control over material properties and its significance to spider ecology and evolution, and also provide inspiration for future manoeuvrable robot designs.

  13. Preparation and characterization of regenerated fiber from the aqueous solution of Bombyx mori cocoon silk fibroin

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Zhenghua [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Department of Application Engineering, ZheJiang Vocational College of Economic and Trade, HangZhou, ZheJiang 310018 (China); Imada, Takuzo [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Asakura, Tetsuo, E-mail: asakura@cc.tuat.ac.jp [Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2009-10-15

    The regenerated silk fibers with high strength and high biodegradability were prepared from the aqueous solution of Bombyx mori silk fibroin from cocoons with wet spinning method. Although the tensile strength of the regenerated silk fibroin fiber, 210 MPa is still half of the strength of native silk fiber, the diameter of the fiber is about 100 {mu}m which is suitable for monofilament of suture together with high biodegradability. The high concentration (30%, w/v) of the aqueous solution of the silk fibroin which corresponds to the high concentration in the middle silkgland of silkworm was obtained. This was performed by adjusting the pH of the aqueous solution to 10.4 which corresponds to pK{sub a} value of the OH group of Tyr residues in the silk fibroin. The mixed solvent, methanol/acetic acid (7:3 in volume ratio) was used as coagulant solvent for preparing the regenerated fiber. The structural change of silk fibroin fiber by stretching was monitored with both {sup 13}C solid state NMR and X-ray diffraction methods, indicating that the high strength of the fiber is related with the long-range orientation of the silk fibroin chain with {beta}-sheet structure.

  14. Highly water-absorbing silk yarn with interpenetrating network via in situ polymerization.

    Science.gov (United States)

    Lee, Ka I; Wang, Xiaowen; Guo, Xia; Yung, Ka-Fu; Fei, Bin

    2017-02-01

    Silk was modified via in situ polymerization of two monomers acrylamide and sodium acrylate by swelling in an effective LiBr dissolution system. Swelling of natural silks in LiBr solutions of low concentration was clearly observed under optical microscope, and their conformational changes were revealed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Dissolution tests and FTIR spectra of these modified silks suggested the presence of interpenetrating network of polyacrylamide and poly(sodium acrylate) in the silk yarns. These modified silks exhibited superior water absorption to that of raw silk and greatly improved mechanical properties in both dry and wet states. These novel modified silks also showed low cytotoxicity towards skin keratinocytes, having potential applications in biomedical textiles. This modification method by in situ polymerization after swelling in LiBr provides a new route to highly enhance the properties and performance of silk for various applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. The protective ability of Camellia meal extract on the silk protein

    Science.gov (United States)

    Weng, JZ; Cai, C.; Zhang, DY; Dai, BK

    2018-02-01

    With the enhancement of living standards, people pay more and more attention to the health. The edible oil become more and more popular, but also produced a large amount of Camellia meal which can not fully put into utilization. In this study, the extracting liquid of Camellia meal was used on the process of silk degumming. Firstly, tussah silk was treated by degumming in the Na2CO3 solution, and the preliminary condition of tussah silk degumming was obtained by orthogonal experiment: the concentration Na2CO3 was 0.1%, the degumming time was 1 hour, and the ratio of silk/water was 40:1. Then the extract of Camellia meal (GCJSY) was added before the bleaching process of tussah silk to investigate the protective ability of GCJSY on the silk protein basry on the residual ratio of the silk. While the concentration of GYJSY was 0.08%, the residual ratio of silk after degumming in the Na2CO3 solution and bleaching in the 2% H2O2 solution was 87.2%.

  16. Study on improving antioxidant and antibacterial activities of silk fibroin by irradiation treatment

    International Nuclear Information System (INIS)

    Tran Bang Diep; Nguyen Van Binh; Hoang Phuong Thao; Hoang Dang Sang; Nguyen Thuy Huong Trang

    2014-01-01

    The silk fibroin solutions were prepared in solvent system of CaCl 2 . CH 3 CH 2 OH. H 2 O (mole ratio = 1:2:8) followed dialysis against deionized water. The 3% silk fibroin solutions were irradiated under gamma Co-60 source with dose ranging from 0 to 50 kGy at Hanoi Irradiation Centre and bioactivities of the irradiated silk fibroin solutions were investigated with different radiation doses. The results indicated that the antioxidant and antibacterial activities of fibroin were much improved by gamma irradiation. Maximum value of DPPH radical scavenging activity was 70.4% for the solution of silk fibroin irradiated at 10 kGy. Silk fibroin solutions irradiated at doses higher than 10 kGy also exhibited rather high antibacterial activity against E. coli and S. aureus. In order to estimate the applicability of our irradiated fibroin, the silk fibroin solutions were lyophilized to obtain a pure fibroin powder, then their bio-activities were compared with those of commercial silk fibroin (Proteines De Soie/ Zijdeproteine, Bioflore, Canada). Our fibroin powder revealed higher antioxidant and antibacterial activities. The amino acid compositions of our irradiated fibroin were also higher than that of the commercial product. Thus, the irradiated silk fibroin can be used for further application in cosmetic and other related fields. (author)

  17. Distinct spinning patterns gain differentiated loading tolerance of silk thread anchorages in spiders with different ecology.

    Science.gov (United States)

    Wolff, Jonas O; van der Meijden, Arie; Herberstein, Marie E

    2017-07-26

    Building behaviour in animals extends biological functions beyond bodies. Many studies have emphasized the role of behavioural programmes, physiology and extrinsic factors for the structure and function of buildings. Structure attachments associated with animal constructions offer yet unrealized research opportunities. Spiders build a variety of one- to three-dimensional structures from silk fibres. The evolution of economic web shapes as a key for ecological success in spiders has been related to the emergence of high performance silks and thread coating glues. However, the role of thread anchorages has been widely neglected in those models. Here, we show that orb-web (Araneidae) and hunting spiders (Sparassidae) use different silk application patterns that determine the structure and robustness of the joint in silk thread anchorages. Silk anchorages of orb-web spiders show a greater robustness against different loading situations, whereas the silk anchorages of hunting spiders have their highest pull-off resistance when loaded parallel to the substrate along the direction of dragline spinning. This suggests that the behavioural 'printing' of silk into attachment discs along with spinneret morphology was a prerequisite for the evolution of extended silk use in a three-dimensional space. This highlights the ecological role of attachments in the evolution of animal architectures. © 2017 The Author(s).

  18. Radiological diagnosis of the adrenal glands

    International Nuclear Information System (INIS)

    Engelbrecht, V.

    2005-01-01

    The adrenal gland is a common site of disease involving hormonal dysfunction as well as benign and malignant masses. Radiology, especially computed tomography (CT) and magnetic resonance (MR), plays a critical role in detecting and characterizing diseases affecting the adrenal gland. This paper contains a summary of the most important diseases of the adrenal gland and presents criteria for differentiating between benign and malignant masses as well as an algorithm for the diagnostic steps in incidentaloma. (orig.)

  19. Description of the last nymphal instar of Talipes appendiculatus (Hemiptera: Membracidae: Membracinae, and notes on the biology of the immatures and adults

    Directory of Open Access Journals (Sweden)

    Frederico Lencioni-Neto

    Full Text Available ABSTRACT The last instar nymph of Talipes appendiculatus (Fonseca is described and illustrated, and biological data are given on the immatures and adults. The 5th instar nymph has the body covered with tuberculate chalazae; head and thorax without scoli; abdomen with terga III-VIII with single dorsal scoli, all different in size, III and VIII small, V the largest about 2x longer than wide. Descriptions of the adults (male and female are also provided, with the addition of some new characters. The species (adults, immatures of various stages has been collected on branches of Cassia fistula L. (Leguminosae: Caesalpinioidea, and is frequently attended by bees and wasps.

  20. Morphology and identification of the final instar nymphs of three cicadas (Hemiptera, Cicadidae) in Guanzhong Plain, China based on comparative morphometrics.

    Science.gov (United States)

    Hou, Zehai; Li, Qinglong; Wei, Cong

    2014-01-01

    The present investigation provides comparative morphometrics of the final instar nymphs of three dominant cicada species, i.e., Cryptotympana atrata (Fabricius), Meimuna mongolica (Distant) and Platypleura kaempferi (Fabricius), in Guanzhong Plain, China. Particularly, characters on the antennae, legs, and apex of abdomen of both males and females of these three species were investigated and analyzed. In addition, the numbers of hind tibial spines of the final instar nymphs of 21 representatives of Cicadoidea were compared. The results provide useful characteristics for nymph identification of related species and for further taxonomic and phylogenetic analysis of Cicadoidea.

  1. Morphology and identification of the final instar nymphs of three cicadas (Hemiptera, Cicadidae in Guanzhong Plain, China based on comparative morphometrics

    Directory of Open Access Journals (Sweden)

    Zehai Hou

    2014-07-01

    Full Text Available The present investigation provides comparative morphometrics of the final instar nymphs of three dominant cicada species, i.e., Cryptotympana atrata (Fabricius, Meimuna mongolica (Distant and Platypleura kaempferi (Fabricius, in Guanzhong Plain, China. Particularly, characters on the antennae, legs, and apex of abdomen of both males and females of these three species were investigated and analyzed. In addition, the numbers of hind tibial spines of the final instar nymphs of 21 representatives of Cicadoidea were compared. The results provide useful characteristics for nymph identification of related species and for further taxonomic and phylogenetic analysis of Cicadoidea.

  2. Parotitis and Sialendoscopy of the Parotid Gland.

    Science.gov (United States)

    Hernandez, Stephen; Busso, Carlos; Walvekar, Rohan R

    2016-04-01

    Nonneoplastic disorders of the salivary glands involve inflammatory processes. These disorders have been managed conservatively with antibiotics, warm compresses, massage, sialogogues, and adequate hydration. Up to 40% of patients may have an inadequate response or persistent symptoms. When conservative techniques fail, the next step is operative intervention. Sialendoscopy offers a minimally invasive option for the diagnosis and management of chronic inflammatory disorders of the salivary glands and offers the option of gland and function preservation. In this article, we review some of the more common nonneoplastic disorders of the parotid gland, indications for diagnostic and interventional sialendoscopy, and operative techniques. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Lacrimal Gland Pathologies from an Anatomical Perspective

    Directory of Open Access Journals (Sweden)

    Mahmut Sinan Abit

    2015-06-01

    Full Text Available Most of the patients in our daily practice have one or more ocular surface disorders including conjucntivitis, keratitis, dry eye disease, meibomian gland dysfunction, contact lens related symptoms, refractive errors,computer vision syndrome. Lacrimal gland has an important role in all above mentioned pathologies due to its major secretory product. An anatomical and physiological knowledge about lacrimal gland is a must in understanding basic and common ophthalmological cases. İn this paper it is aimed to explain the lacrimal gland diseases from an anatomical perspective.

  4. Exocrine glands of Schwarziana quadripunctata (Hymenoptera, Apinae, Meliponini

    Directory of Open Access Journals (Sweden)

    C. CRUZ-LANDIM

    Full Text Available This article describes the location, anatomy, histology and ontogeny of adult Schwarziana quadripunctata exocrine glands. These glands appear either as individualized organs (salivary gland system and Dufour gland or as epidermis differentiation (tegumentary glands. Variations in the occurrence and degree of development among colony components with regard to their degree of maturity are also described.

  5. Flexible, highly sensitive pressure sensor with a wide range based on graphene-silk network structure

    Science.gov (United States)

    Liu, Ying; Tao, Lu-Qi; Wang, Dan-Yang; Zhang, Tian-Yu; Yang, Yi; Ren, Tian-Ling

    2017-03-01

    In this paper, a flexible, simple-preparation, and low-cost graphene-silk pressure sensor based on soft silk substrate through thermal reduction was demonstrated. Taking silk as the support body, the device had formed a three-dimensional structure with ordered multi-layer structure. Through a simple and low-cost process technology, graphene-silk pressure sensor can achieve the sensitivity value of 0.4 kPa - 1 , and the measurement range can be as high as 140 kPa. Besides, pressure sensor can have a good combination with knitted clothing and textile product. The signal had good reproducibility in response to different pressures. Furthermore, graphene-silk pressure sensor can not only detect pressure higher than 100 kPa, but also can measure weak body signals. The characteristics of high-sensitivity, good repeatability, flexibility, and comfort for skin provide the high possibility to fit on various wearable electronics.

  6. Research On Degradation Of Silk Fibroin By Combination Of Electron Beam Irradiation And Hydrothermal Processing

    International Nuclear Information System (INIS)

    Nguyen Thi Kim Lan; Dang Van Phu; Le Anh Quoc; Nguyen Quoc Hien

    2014-01-01

    Silk fibers and silk proteins have been demonstrated to be useful to apply in the textile industry, biomedical, cosmetics, pharmaceuticals. In this study, the effects of electron beam (EB) irradiation combined with hydrothermal processing to the solubility of silk fibroin and generation of soluble silk protein were investigated. The solubility of unirradiated and irradiated fibroin were greater than 80 % when hydrothermal degradation was performed in the sodium hydroxide solution at appropriate concentration of 0.05 M. However, the solubility of irradiated fibroin was greater than that of unirradiated sample. The protein content increased from 0.4617 to 0.6530 mg/mg when irradiation doses increased from 0 to 200 kGy, respectively. The molecular weight of protein was determined by SDS-PAGE method. The characteristics of silk protein were confirmed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). (author)

  7. Morphological Features of the Porcine Lacrimal Gland and Its Compatibility for Human Lacrimal Gland Xenografting

    OpenAIRE

    Henker, Robert; Scholz, Michael; Gaffling, Simone; Asano, Nagayoshi; Hampel, Ulrike; Garreis, Fabian; Hornegger, Joachim; Paulsen, Friedrich

    2013-01-01

    In this study, we present first data concerning the anatomical structure, blood supply and location of the lacrimal gland of the pig. Our data indicate that the porcine lacrimal gland may serve as a potential xenograft candidate in humans or as an animal model for engineering of a bioartificial lacrimal gland tissue construct for clinical application. For this purpose, we used different macroscopic preparation techniques and digital reconstruction of the histological gland morphology to gain ...

  8. Morus planting and silk production in Oxus civilization (2000 BC), Transoxiana

    Science.gov (United States)

    Zhou, X.; Li, X.; Wang, J.

    2017-12-01

    Silk is the most important luxury in ancient trade, which promoted communications between east and west civilizations that facilitated the development of them. Currently, probably more than 99% of the silk in commerce in the world today comes from a single species called the silkworm or mulberry silk moth, Bombyx mori (L.), of the family Bombycidae. At present, a list of occurrences of unearthed early silk thread, textile and terracotta figures of China suggests that wild silk has been widely used for weave in Yangtze river and Yellow River basin at least 5000 cal yr BP. On the other hand, the earliest silk fabric out China is from the earliest civilization Harappa site (4500-4000 cal a BP) that confirmed the early use of wild silkworms in South Asia.. In addition, in the Egyptian Deir al Medina relics site, the unearthed silk also as old as nearly 3000 cal a BP, and a serials of pre-han silk also unearthed 3000-2500 cal a BP in Europe. But, the appearance of these out-China silk is usually considered to be the result of the early trade or wild silkmoth products. Here we present a synthesis study of chronology, entomology, protein group, the paleoethnobotany form three Bronze Age site (Sapalli, Jarzgudan, Molleli) concerning on the paleo environment, agriculture gardening, and the possible mulberry silkworm utilization in Bronze Age Tensoxiana 4000 cal a BP. Together with archaeobotany and chronology data from Xinjiang, Hexi corridor and the Loess Plateau in China, we analysis the status of the mulberry silk factory in Bronze Age in Transoxiana and it possible connection to ancient China.

  9. Preparation and characterization of silk fibroin as a biomaterial with potential for drug delivery

    Directory of Open Access Journals (Sweden)

    Zhang Hao

    2012-06-01

    Full Text Available Abstract Background Degummed silk fibroin from Bombyx mori (silkworm has potential carrier capabilities for drug delivery in humans; however, the processing methods have yet to be comparatively analyzed to determine the differential effects on the silk protein properties, including crystalline structure and activity. Methods In this study, we treated degummed silk with four kinds of calcium-alcohol solutions, and performed secondary structure measurements and enzyme activity test to distinguish the differences between the regenerated fibroins and degummed silk fibroin. Results Gel electrophoresis analysis revealed that Ca(NO32-methanol, Ca(NO32-ethanol, or CaCl2-methanol treatments produced more lower molecular weights of silk fibroin than CaCl2-ethanol. X-ray diffraction and Fourier-transform infrared spectroscopy showed that CaCl2-ethanol produced a crystalline structure with more silk I (α-form, type II β-turn, while the other treatments produced more silk II (β-form, anti-parallel β-pleated sheet. Solid-State 13C cross polarization and magic angle spinning-nuclear magnetic resonance measurements suggested that regenerated fibroins from CaCl2-ethanol were nearly identical to degummed silk fibroin, while the other treatments produced fibroins with significantly different chemical shifts. Finally, enzyme activity test indicated that silk fibroins from CaCl2-ethanol had higher activity when linked to a known chemotherapeutic drug, L-asparaginase, than the fibroins from other treatments. Conclusions Collectively, these results suggest that the CaCl2-ethanol processing method produces silk fibroin with biomaterial properties that are appropriate for drug delivery.

  10. Interaction Between Short-Term Heat Pretreatment and Avermectin On 2nd Instar Larvae of Diamondback Moth, Plutella Xylostella (Linn)

    Science.gov (United States)

    Gu, Xiaojun; Tian, Sufen; Wang, Dehui; Gao, Fei

    2009-01-01

    Based on the cooperative virulence index (c.f.), the interaction effect between short-term heat pretreatment and avermectin on 2nd instar larvae of diamondback moth (DBM), Plutella xylostella (Linnaeus), was assessed. The results suggested that the interaction results between short-term heat pretreatment and avermectin on the tested insects varied with temperature level as well as its duration and avermectin concentration. Interaction between heat pretreatment at 30°C and avermectin mainly resulted in addition. Meanwhile, pretreatment at 35°C for 2 or 4 h could antagonize the toxicity of avermectin at lower concentrations, which indicated a hormetic effect occurred. The results indicate that cooperative virulence index (c.f.) may be adopted in hormetic effect assessment. PMID:19809544

  11. Pituitary gland imaging and outcome.

    Science.gov (United States)

    Di Iorgi, Natascia; Morana, Giovanni; Gallizia, Anna Lisa; Maghnie, Mohamad

    2012-01-01

    Magnetic resonance imaging (MRI) allows a detailed and precise anatomical study of the pituitary gland by differentiating between the anterior and posterior pituitary lobes. The identification of posterior pituitary hyperintensity, now considered a marker of neurohypophyseal functional integrity, has been the most striking advance for the diagnosis and understanding of anterior and posterior pituitary diseases. The advent of MRI has in fact led to a significant improvement in the understanding of the pathogenesis of disorders that affect the hypothalamo-pituitary area. Today, there is convincing evidence to support the hypothesis that marked MRI differences in pituitary morphology indicate a diverse range of disorders which affect the organogenesis and function of the anterior pituitary gland with different prognoses. Furthermore, the association of extrapituitary malformations accurately defined by MRI has supported a better definition of several conditions linked to pituitary hormone deficiencies and midline defects. MRI is a very informative procedure that should be used to support a diagnosis of hypopituitarism. It is useful in clinical management, because it helps endocrinologists determine which patients to target for further molecular studies and genetic counselling, which ones to screen for additional hormone deficits, and which ones may need growth hormone replacement into adult life. Copyright © 2012 S. Karger AG, Basel.

  12. Schwannoma of the adrenal gland

    Directory of Open Access Journals (Sweden)

    Anunayi Jeshtadi

    2014-07-01

    Full Text Available Visceral schwannomas are extremely rare and are usually discov-ered incidentally on USG/CT-Scan. Primary schwannomas of the adrenal gland are extremely uncommon. It has been theorized that they originate from Schwann cells that insulate the nerve fi-bers innervating the adrenal medulla. Histopathological examina-tion coupled with immunohistochemistry provides the definitive diagnosis. A 55 year old normotensive female presented with pain in the right loin since 5 months. Her renal parameters were normal. Contrast enhanced computed tomography of abdomen showed a well delineated 6.5 x 5cms mass at upper pole of her right kidney. 24-hour urinary metanephrine was slightly elevated (3.07mg/24hrs. A decline in Serum cortisol levels was observed following a dexamethasone suppression test (18.89nmol/l. Histopathological examination revealed a spindle cell tumor. Immunohistochemistry showed strong and diffuse positive staining for S-100 with negative expression for CD-117, desmin, CD-34, HMB-45, synaptophysin, chromogranin, cytokeratin, and SMA. Ki-67 index was 2%.A diagnosis of cellular schwannoma of adrenal gland was confirmed.

  13. Effect of Na2CO3 degumming concentration on LiBr-formic acid-silk fibroin solution properties

    Directory of Open Access Journals (Sweden)

    Liu Zhi

    2016-01-01

    Full Text Available Salt-acid system has been proved to be of high efficiency for silk fibroin dissolution. Using salt-acid system to dissolve silk, native silk fibrils can be preserved in the regenerated solution. Increasing experiments indicate that acquirement of silk fibrils in solution is strongly associated with the degumming process. In this study, the effect of sodium carbonate degumming concentration on solution properties based on lithium bromide-formic acid dissolution system was systematically investigated. Results showed that the morphology transformation of silk fibroin in solution from nanospheres to nanofibrils is determined by sodium carbonate concentration during the degumming process. Solutions containing different silk fibroin structure exhibited different rheological behaviors and different electrospinnability, leading to different electrospun nanofibre properties. The results have guiding significance for preparation and application of silk fibroin solutions.

  14. Acylation Modification of Antheraea pernyi Silk Fibroin Using Succinic Anhydride and Its Effects on Enzymatic Degradation Behavior

    Directory of Open Access Journals (Sweden)

    Xiufang Li

    2013-01-01

    Full Text Available The degradation rate of tissue engineering scaffolds should match the regeneration rate of new tissues. Controlling the degradation behavior of silk fibroin is an important subject for silk-based tissue engineering scaffolds. In this study, Antheraea pernyi silk fibroin was successfully modified with succinic anhydride and then characterized by zeta potential, ninhydrin method, and FTIR. In vitro, three-dimensional scaffolds prepared with modified silk fibroin were incubated in collagenase IA solution for 18 days to evaluate the impact of acylation on the degradation behavior. The results demonstrated that the degradation rate of modified silk fibroin scaffolds was more rapid than unmodified ones. The content of the β-sheet structure in silk fibroin obviously decreased after acylation, resulting in a high degradation rate. Above all, the degradation behavior of silk fibroin scaffolds could be regulated by acylation to match the requirements of various tissues regeneration.

  15. Orientational structure formation of silk fibroin with anisotropic properties in solutions; Orientastionnoe strukturoobrazovanie fibroina shelka s anizotropnymi svojstvami v rastvorakh

    Energy Technology Data Exchange (ETDEWEB)

    Kholmuminov, A A [AS RU, Institute of Polymer Chemistry and Physics, Tashkent (Uzbekistan)

    2008-06-15

    Key words:silk fibroin, dissolution, solution's model systems, gelation, orientational crystallization, optical polarization, longitudinal stream, {alpha} - {beta} transition, structure formation, phase transformations, relaxation, anisotropy of swelling and desorption, thermo- and biodegradation. Subjects of the inquiry: silk fibroin is the main subject of investigation. Fibroin's solutions were obtained on the base of water and organic solvents, containing salts. Comparative investigations were carried out by using biosolution - secretion of silkworm, solutions of silk sericin, cotton cellulose, methylcellulose, polystyrene and (co) polycrylonitrile. Aim of the inquiry: the elucidation of the regularities of silk fibroin anisotropic structures formation in the direct generation of orientational ordering in solutions taking into account of influences of its the molecular structures, configuration information, {alpha} - {beta} conformational transformations, and development jointly using polarization-optical and hydrodynamic methods to control of structure formation. And also definition of possibility fields for use biopolymers anisotropic structure formation principles. Method of inquiry: birefringence, dispersion optical rotation, circular dichroism, polarization- ultramicroscope, ultracentrifuge, viscosimetry, potentiometry, differential thermal analysis, chromatography, x-ray analysis, spectroscopy. The results achieved and their novelty: the physical regularity amorphous-crystalline fibroin dissolutions in salt-containing solvents based on chains melting, distribution and redistribution were recognized; fibroin statistical parameters, molecular-mass and conformational characteristics were established; It was shown that fibroin molecules turned into fully uncoiled and oriented state with the breakdown decay of {alpha}-spiral chain sections by I type phase transition mechanism, but in oriented state with {alpha}-spiral conservation by II type transition; the

  16. Comparative ultrasound measurement of normal thyroid gland ...

    African Journals Online (AJOL)

    2011-08-31

    Aug 31, 2011 ... the normal thyroid gland has a homogenous increased medium level echo texture. The childhood thyroid gland dimension correlates linearly with age and body surface unlike adults. [14] Iodothyronine (T3) and thyroxine (T4) are thyroid hormones which function to control the basal metabolic rate (BMR).

  17. Ductal carcinoma of the parotid gland.

    Science.gov (United States)

    Eriksen, H E; Greisen, O; Hastrup, N

    1987-06-01

    A case of ductal carcinoma of the parotid gland is described. The medical literature contains only 13 previous reports on this kind of adenocarcinoma of the parotid gland. The tumour is characterized by its histologic resemblance to ductal carcinomas of the breast and prostate. The course of previously described cases suggests that this tumour has a highly aggressive biological behaviour.

  18. Gordon Research Conference on Mammary Gland Biology

    International Nuclear Information System (INIS)

    1989-01-01

    The 1989 conference was the tenth in the series of biennial Gordon Research Conferences on Mammary Gland Biology. Traditionally this conference brings together scientists from diverse backgrounds and experience but with a common interest in the biology of the mammary gland. Investigators from agricultural and medical schools, biochemists, cell and molecular biologists, endocrinologists, immunologists, and representatives from the emerging biotechnology industries met to discuss current concepts and results on the function and regulation of the normal and neoplastic mammary gland in a variety of species. Of the participants, approximately three-fourths were engaged in studying the normal mammary gland function, whereas the other quarter were engaged in studying the neoplastic gland. The interactions between scientists, clinicians, veterinarians examining both normal and neoplastic cell function serves to foster the multi-disciplinary goals of the conference and has stimulated many cooperative projects among participants in previous years

  19. Homeobox Genes in the Rodent Pineal Gland

    DEFF Research Database (Denmark)

    Rath, Martin Fredensborg; Rohde, Kristian; Klein, David C

    2013-01-01

    The pineal gland is a neuroendocrine gland responsible for nocturnal synthesis of melatonin. During early development of the rodent pineal gland from the roof of the diencephalon, homeobox genes of the orthodenticle homeobox (Otx)- and paired box (Pax)-families are expressed and are essential...... for normal pineal development consistent with the well-established role that homeobox genes play in developmental processes. However, the pineal gland appears to be unusual because strong homeobox gene expression persists in the pineal gland of the adult brain. Accordingly, in addition to developmental...... functions, homeobox genes appear to be key regulators in postnatal phenotype maintenance in this tissue. In this paper, we review ontogenetic and phylogenetic aspects of pineal development and recent progress in understanding the involvement of homebox genes in rodent pineal development and adult function...

  20. Cancer of the thyroid and salivary glands

    International Nuclear Information System (INIS)

    Ezaki, H.; Hayashi, Y.; Ishimaru, Toranosuke; Takeichi, N.

    1986-01-01

    The relationship of atomic bomb exposure to tumors of the head and neck has been studied in detail for the thyroid and salivary gland. It has been deomonstrated by animal experiments and studies conducted on those undergoing radiation therapy of the neck during childhood, and on those exposed to radioactive fallout from hydrogen-bomb tests in the Marshall Islands, that thyroid neoplasms can be induced by radiation. Although it was assumed that radiation would ahve a similar effect on the salivary gland located near the thyroid gland, it was in the 1970s that studies were commenced on the salivary gland. A study of the Adult Health Study population presented data which show that the incidence of salivary gland tumors was 9.3-fold higher in the group exposed to 300+ rad than in the control group and when confined only to malignant tumors the incidence was 21.8-fold higher

  1. Assessing the impact of the maritime silk road

    Directory of Open Access Journals (Sweden)

    Orestis Schinas

    2017-09-01

    Full Text Available The plans for the Maritime Silk Road affect the existing liner services. The purpose of this paper is to quantify using the terms of network theory the impact of these plans and to project the effects on the fleet, utilization, port throughput, and carbon footprint. The analysis is based on publicly available information and reasonable fleet deployment assumptions. It also considers current and alternative routing schedules from Shanghai to Europe. The impact of existing and expected emission control areas (ECAs along the port chains is also considered.

  2. Material quality assessment of silk nanofibers based on swarm intelligence

    Science.gov (United States)

    Brandoli Machado, Bruno; Nunes Gonçalves, Wesley; Martinez Bruno, Odemir

    2013-02-01

    In this paper, we propose a novel approach for texture analysis based on artificial crawler model. Our method assumes that each agent can interact with the environment and each other. The evolution process converges to an equilibrium state according to the set of rules. For each textured image, the feature vector is composed by signatures of the live agents curve at each time. Experimental results revealed that combining the minimum and maximum signatures into one increase the classification rate. In addition, we pioneer the use of autonomous agents for characterizing silk fibroin scaffolds. The results strongly suggest that our approach can be successfully employed for texture analysis.

  3. NMR analysis of silk for the interpretation of ancient history

    International Nuclear Information System (INIS)

    Chujo, Riichiro

    1998-01-01

    The aim of this paper is the characterization of archaeological silk with the aid of nuclear magnetic resonance (NMR). In this paper the nucleus is confined to 13C as a stable isotope carbon which is the most basic element in organic compounds. Among the stable carbon isotopes 12C is the most abundant but it has no magnetic moment and the natural abundance of 13C is only 1.108% and this isotope is frequently used in NMR due to its non-zero magnetic moment

  4. Silk fibroin/pullulan blend films: Preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Shivananda, C. S.; Rao, B. Lakshmeesha; Madhukumar, R.; Asha, S. [Department of Studies in Physics, Mangalore University, Mangalagangotri – 574 199 (India); Sarojini, B. K. [Department of Industrial Chemistry, Mangalore University, Mangalagangotri, Mangalore –574 199 (India); Somashekhar, R. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore – 570 006 (India); Sangappa, Y., E-mail: syhalabhavi@yahoo.co.in [Department of Studies in Physics, Mangalore University, Mangalagangotri – 574 199 (India); School of Material Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2016-05-23

    In this work silk fibroin/pullulan blend films have been prepared by solution casting method. The blend films were examined for structural, and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results indicate that with the introduction of pullulan, the interaction between SF and pullulan in the blend films induced the conformation transition of SF films and amorphous phase increases with increasing pullulan ratio. The thermal properties of the blend films were improved significantly in the blend films.

  5. Hemolin expression in the silk glands of Galleria mellonella in response to bacterial challenge and prior to cell disintegration

    Czech Academy of Sciences Publication Activity Database

    Shaik, Haq Abdul; Sehnal, František

    2009-01-01

    Roč. 55, č. 9 (2009), s. 781-787 ISSN 0022-1910 R&D Projects: GA AV ČR IAA5007402 Institutional research plan: CEZ:AV0Z50070508 Keywords : cell recognition * hemolin * 20-hydroxyecdysone Subject RIV: ED - Physiology Impact factor: 2.235, year: 2009

  6. Silk fibroin/gold nanocrystals: a new example of biopolymer-based nanocomposites

    Science.gov (United States)

    Noinville, S.; Garnier, A.; Courty, A.

    2017-05-01

    The dispersion of nanoparticles in ordered polymer nanostructures can provide control over particle location and orientation, and pave the way for tailored nanomaterials that have enhanced mechanical, electrical, or optical properties. Here we used silk fibroin, a natural biopolymer, to embed gold nanocrystals (NCs), so as to obtain well-ordered structures such as nanowires and self-assembled triangular nanocomposites. Monodisperse gold NCs synthesized in organic media are mixed to silk fibroin and the obtained nanocomposites are characterized by UV-visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and Infrared spectroscopy. The optical properties study of gold NCs and silk-gold nanocomposites shows that the Surface Plasmon band is blue shifted compared to gold NCs. The size and shape of NCs gold superlattices can be well controlled by the presence of silk fibroin giving nanowires and also self-assembled triangular nanocomposites as characterized by TEM, FE-SEM and AFM. The strong interaction between gold NCs and silk fibroin is also revealed by the conformation change of silk protein in presence of gold NCs, as shown by FTIR analysis. The formation of such ordered nanocomposites (gold NCs/silk fibroin) will provide new nanoplasmonic devices.

  7. Introducing biomimetic shear and ion gradients to microfluidic spinning improves silk fiber strength.

    Science.gov (United States)

    Li, David; Jacobsen, Matthew M; Gyune Rim, Nae; Backman, Daniel; Kaplan, David L; Wong, Joyce Y

    2017-05-31

    Silkworm silk is an attractive biopolymer for biomedical applications due to its high mechanical strength and biocompatibility; as a result, there is increasing interest in scalable devices to spin silk and recombinant silk so as to improve and customize their properties for diverse biomedical purposes (Vepari and Kaplan 2007 Prog. Polym. Sci. 32 ). While artificial spinning of regenerated silk fibroins adds tunability to properties such as degradation rate and surface functionalization, the resulting fibers do not yet approach the mechanical strength of native silkworm silk. These drawbacks reduce the applicability and attractiveness of artificial silk (Kinahan et al 2011 Biomacromolecules 12 ). Here, we used computational fluid dynamic simulations to incorporate shear in tandem with biomimetic ion gradients by coupling a modular novel glass microfluidic device to our previous co-axial flow device. Fibers spun with this combined apparatus demonstrated a significant increase in mechanical strength compared to fibers spun with the basic apparatus alone, with a three-fold increase in Young's modulus and extensibility and a twelve-fold increase in toughness. These results thus demonstrate the critical importance of ionic milieu and shear stress in spinning strong fibers from solubilized silk fibroin.

  8. Corn silk aqueous extracts and intraocular pressure of systemic and non-systemic hypertensive subjects.

    Science.gov (United States)

    George, Gladys O; Idu, Faustina K

    2015-03-01

    Hypotensive properties have been attributed to the stigma/style of Zea mays L (corn silk). Although the effect of corn silk extract on blood pressure has been documented in animal studies, we are not aware of any study on its effect on human blood pressure and intraocular pressure. A randomised study was carried out on the effect of water only, masked doses of corn silk aqueous extract (60, 130, 192.5 and 260 mg/kg body weight) on intraocular pressure and blood pressure of 20 systemic and 20 non-systemic hypertensive subjects. Intraocular pressure and blood pressure were measured at baseline and every hour for eight hours after administering water or a masked dose of corn silk aqueous extract. Each dose was administered at two-week intervals to each subject in the two study groups. The results showed that the last three doses of corn silk aqueous extract gave a statistically significant reduction (p Corn silk aqueous extract has a lowering effect on intraocular pressure in systemic and non-systemic hypertensive subjects. This may have resulted from the fall in blood pressure that is due to potassium-induced natriuresis and diuresis caused by the high potassium content in the high doses of the corn silk extract. © 2015 The Authors. Clinical and Experimental Optometry © 2015 Optometry Australia.

  9. The effect of hirudin modification of silk fibroin on cell growth and antithrombogenicity

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qiongyu; Tu, Fangfang; Liu, Yunfei; Zhang, Yujin; Li, Helei; Kang, Zhao [National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, No. 199 Ren-ai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China); Yin, Yin [Laboratory Animal Research Center, Soochow University, Suzhou, Jiangsu 215123 (China); Wang, Jiannan, E-mail: wangjn@suda.edu.cn [National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, No. 199 Ren-ai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China)

    2017-06-01

    Thrombus formation remains a particular challenge for small-diameter vascular grafts. In this study, the direct thrombin inhibitor hirudin (Hir) was used to modify silk fibroin films in an attempt to enhance its antithrombogenic properties. Hir was successfully attached to silk fibroin and uniformly distributed in the regenerative material. Hir-modified films showed good cytocompatibility, and supported adhesion and proliferation of fibroblasts (L929), human umbilical vascular endothelial cells (HUVECs) and human aortic smooth muscle cells (HASMCs). Proliferation of HAVSMCs was inhibited by increasing Hir concentration. Activated partial thrombin time (APTT), prothrombin time (PT) and thrombin time (TT) of Hir-modified silk fibroin tubular scaffolds (SFTSs) were all increased markedly compared with fresh rabbit blood, ethanol-treated SFTS and unmodified SFTS, demonstrating the improved antithrombogenicity of SFTSs following modification with Hir. - Highlights: • A direct thrombin inhibitor hirudin was used to modify silk fibroin. • Antithrombogenic property of Hir-modified silk fibroin films was improved. • Hir-modified silk fibroin films supported adhesion and proliferation of HUVECs and HAVSMCs. • Proliferation of HAVSMCs on silk fibroin films was inhibited by increasing Hir concentration.

  10. Research on degradation of silk fibroin by combination of electron beam irradiation and hydrothermal processing

    International Nuclear Information System (INIS)

    Nguyen Thi Kim Lan; Dang Van Phu; Le Anh Quoc; Nguyen Quoc Hien

    2014-01-01

    Silk fibers and silk proteins have been demonstrated to be useful to apply in the textile industry, biomedical, cosmetics, pharmaceuticals. In this study, the effects of electron beam (EB) irradiation combined with hydrothermal processing to the solubility of silk fibroin and generation of soluble silk protein were investigated. The solubility of unirradiated and irradiated fibroin samples were greater than 80 % when hydrothermal degradation was performed in the sodium hydroxide solution at an appropriate concentration of 0.05 M. However, the solubility of irradiated fibroin was greater than that of unirradiated sample. The soluble silk protein content increased from 0.462 to 0.653 mg protein/mg silk fibroin when irradiation doses increased from 0 to 200 kGy, respectively. The molecular weight of protein was determined by SDS-PAGE method. The characteristics of silk protein were confirmed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). (author)

  11. Regulation of Silk Material Structure by Temperature-Controlled Water Vapor Annealing

    Science.gov (United States)

    Hu, Xiao; Shmelev, Karen; Sun, Lin; Gil, Eun-Seok; Park, Sang-Hyug; Cebe, Peggy; Kaplan, David L.

    2011-01-01

    We present a simple and effective method to obtain refined control of the molecular structure of silk biomaterials through physical temperature-controlled water vapor annealing (TCWVA). The silk materials can be prepared with control of crystallinity, from a low content using conditions at 4°C (alpha-helix dominated silk I structure), to highest content of ~60% crystallinity at 100°C (beta-sheet dominated silk II structure). This new physical approach covers the range of structures previously reported to govern crystallization during the fabrication of silk materials, yet offers a simpler, green chemistry, approach with tight control of reproducibility. The transition kinetics, thermal, mechanical, and biodegradation properties of the silk films prepared at different temperatures were investigated and compared by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), uniaxial tensile studies, and enzymatic degradation studies. The results revealed that this new physical processing method accurately controls structure, in turn providing control of mechanical properties, thermal stability, enzyme degradation rate, and human mesenchymal stem cell interactions. The mechanistic basis for the control is through the temperature controlled regulation of water vapor, to control crystallization. Control of silk structure via TCWVA represents a significant improvement in the fabrication of silk-based biomaterials, where control of structure-property relationships is key to regulating material properties. This new approach to control crystallization also provides an entirely new green approach, avoiding common methods which use organic solvents (methanol, ethanol) or organic acids. The method described here for silk proteins would also be universal for many other structural proteins (and likely other biopolymers), where water controls chain interactions related to material properties. PMID:21425769

  12. Novel silk fibroin films prepared by formic acid/hydroxyapatite dissolution method

    International Nuclear Information System (INIS)

    Ming, Jinfa; Liu, Zhi; Bie, Shiyu; Zhang, Feng; Zuo, Baoqi

    2014-01-01

    Bombyx mori silk fibroin from the silkworm was firstly found to be soluble in formic acid/hydroxyapatite system. The rheological behavior of silk fibroin solution was significantly influenced by HAp contents in dissolved solution. At the same time, silk fibroin nanofibers were observed in dissolved solution with 103.6 ± 20.4 nm in diameter. Moreover, the structure behavior of SF films prepared by formic acid/hydroxyapatite dissolution method was examined. The secondary structure of silk fibroin films was attributed to silk II structure (β-sheet), indicating that the hydroxyapatite contents in dissolved solution were not significantly affected by the structure of silk fibroin. The X-ray diffraction results exhibited obviously hydroxyapatite crystalline nature existing in silk fibroin films; however, when the hydroxyapatite content was 5.0 wt.% in dissolved solution, some hydroxyapatite crystals were converted to calcium hydrogen phosphate dehydrate in silk fibroin dissolution process. This result was also confirmed by Fourier transform infrared analysis and DSC measurement. In addition, silk fibroin films prepared by this dissolution method had higher breaking strength and extension at break. Based on these analyses, an understanding of novel SF dissolution method may provide an additional tool for designing and synthesizing advanced materials with more complex structures, which should be helpful in different fields, including biomaterial applications. - Highlights: • SF fibers were firstly successfully dissolved in FA/HAp solution. • The rheological behavior of SF solution was significantly influenced by HAp contents. • SF nanofibrils were observed in FA/HAp solution with 103.6 ± 20.4 nm in diameter. • SF films prepared by FA/HAp dissolution method had higher mechanical properties

  13. Tunable green graphene-silk biomaterials: Mechanism of protein-based nanocomposites.

    Science.gov (United States)

    Wang, Fang; Jyothirmayee Aravind, S S; Wu, Hao; Forys, Joseph; Venkataraman, Venkat; Ramanujachary, Kandalam; Hu, Xiao

    2017-10-01

    Green graphene materials prepared by photoreduction of graphite oxide were first time blended with aqueous-based silk fibroin proteins to improve the mechanical and thermal properties of silk biomaterials, and their nanocomposite interaction mechanism was illustrated. Powder X-ray diffraction (XRD) analysis confirmed the complete exfoliation of graphite oxide to graphene in presence of focused pulses of solar radiation. By varying the concentration of graphene (0.1wt% to 10wt%), a series of free standing graphene-silk films were prepared and were systematically characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and nanoindentation measurements. The homogeneity of graphene in silk as well as the thermal stability of the composite films was demonstrated by thermal gravimetric analysis (TGA) and temperature-modulated differential scanning calorimetry (TMDSC). Surprisingly, silk composite film containing only 0.5wt% of graphene gives the highest Young's modulus of 1.65GPa (about 5.8 times higher than the pure silk's modulus), indicating a nano-composite to micro-composite transition of silk-graphene structure occurred around this mixing ratio. This finding provided an easy approach to improve the elastic modulus and other physical properties of silk materials by adding a tiny amount of graphene sheets. Fibroblast cells studies also proved that these graphene-silk materials can significantly improve cell adhesion, growth and proliferation. This protein nanocomposite study provided a useful model to understand how to manipulate the hydrophobic-hydrophobic and polar-polar interactions between high-surface-area inorganic nanomaterials and amphiphilic protein materials, which has many emerging applications in the material science and engineering, such as bio-device fabrication, drug storage and release, and tissue regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Functional regeneration of ligament-bone interface using a triphasic silk-based graft.

    Science.gov (United States)

    Li, Hongguo; Fan, Jiabing; Sun, Liguo; Liu, Xincheng; Cheng, Pengzhen; Fan, Hongbin

    2016-11-01

    The biodegradable silk-based scaffold with unique mechanical property and biocompatibility represents a favorable ligamentous graft for tissue-engineering anterior cruciate ligament (ACL) reconstruction. However, the low efficiency of ligament-bone interface restoration barriers the isotropic silk graft to common ACL therapeutics. To enhance the regeneration of the silk-mediated interface, we developed a specialized stratification approach implementing a sequential modification on isotropic silk to constitute a triphasic silk-based graft in which three regions respectively referring to ligament, cartilage and bone layers of interface were divided, followed by respective biomaterial coating. Furthermore, three types of cells including bone marrow mesenchymal stem cells (BMSCs), chondrocytes and osteoblasts were respectively seeded on the ligament, cartilage and bone region of the triphasic silk graft, and the cell/scaffold complex was rolled up as a multilayered graft mimicking the stratified structure of native ligament-bone interface. In vitro, the trilineage cells loaded on the triphasic silk scaffold revealed a high proliferative capacity as well as enhanced differentiation ability into their corresponding cell lineage. 24 weeks postoperatively after the construct was implanted to repair the ACL defect in rabbit model, the silk-based ligamentous graft exhibited the enhancement of osseointegration detected by a robust pullout force and formation of three-layered structure along with conspicuously corresponding matrix deposition via micro-CT and histological analysis. These findings potentially broaden the application of silk-based ligamentous graft for ACL reconstruction and further large animal study. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Novel silk fibroin films prepared by formic acid/hydroxyapatite dissolution method

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Jinfa, E-mail: jinfa.ming@gmail.com [National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, Suzhou 215021 (China); Liu, Zhi; Bie, Shiyu [National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, Suzhou 215021 (China); Zhang, Feng [Jiangsu Province Key Laboratory of Stem Cell Research, Medical College, Soochow University, Suzhou 215006 (China); Zuo, Baoqi, E-mail: bqzuo@suda.edu.cn [National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, Suzhou 215021 (China)

    2014-04-01

    Bombyx mori silk fibroin from the silkworm was firstly found to be soluble in formic acid/hydroxyapatite system. The rheological behavior of silk fibroin solution was significantly influenced by HAp contents in dissolved solution. At the same time, silk fibroin nanofibers were observed in dissolved solution with 103.6 ± 20.4 nm in diameter. Moreover, the structure behavior of SF films prepared by formic acid/hydroxyapatite dissolution method was examined. The secondary structure of silk fibroin films was attributed to silk II structure (β-sheet), indicating that the hydroxyapatite contents in dissolved solution were not significantly affected by the structure of silk fibroin. The X-ray diffraction results exhibited obviously hydroxyapatite crystalline nature existing in silk fibroin films; however, when the hydroxyapatite content was 5.0 wt.% in dissolved solution, some hydroxyapatite crystals were converted to calcium hydrogen phosphate dehydrate in silk fibroin dissolution process. This result was also confirmed by Fourier transform infrared analysis and DSC measurement. In addition, silk fibroin films prepared by this dissolution method had higher breaking strength and extension at break. Based on these analyses, an understanding of novel SF dissolution method may provide an additional tool for designing and synthesizing advanced materials with more complex structures, which should be helpful in different fields, including biomaterial applications. - Highlights: • SF fibers were firstly successfully dissolved in FA/HAp solution. • The rheological behavior of SF solution was significantly influenced by HAp contents. • SF nanofibrils were observed in FA/HAp solution with 103.6 ± 20.4 nm in diameter. • SF films prepared by FA/HAp dissolution method had higher mechanical properties.

  16. Molecular and macro-scale analysis of enzyme-crosslinked silk hydrogels for rational biomaterial design.

    Science.gov (United States)

    McGill, Meghan; Coburn, Jeannine M; Partlow, Benjamin P; Mu, Xuan; Kaplan, David L

    2017-11-01

    Silk fibroin-based hydrogels have exciting applications in tissue engineering and therapeutic molecule delivery; however, their utility is dependent on their diffusive properties. The present study describes a molecular and macro-scale investigation of enzymatically-crosslinked silk fibroin hydrogels, and demonstrates that these systems have tunable crosslink density and diffusivity. We developed a liquid chromatography tandem mass spectroscopy (LC-MS/MS) method to assess the quantity and order of covalent tyrosine crosslinks in the hydrogels. This analysis revealed between 28 and 56% conversion of tyrosine to dityrosine, which was dependent on the silk concentration and reactant concentration. The crosslink density was then correlated with storage modulus, revealing that both crosslinking and protein concentration influenced the mechanical properties of the hydrogels. The diffusive properties of the bulk material were studied by fluorescence recovery after photobleaching (FRAP), which revealed a non-linear relationship between silk concentration and diffusivity. As a result of this work, a model for synthesizing hydrogels with known crosslink densities and diffusive properties has been established, enabling the rational design of silk hydrogels for biomedical applications. Hydrogels from naturally-derived silk polymers offer versitile opportunities in the biomedical field, however, their design has largely been an empirical process. We present a fundamental study of the crosslink density, storage modulus, and diffusion behavior of enzymatically-crosslinked silk hydrogels to better inform scaffold design. These studies revealed unexpected non-linear trends in the crosslink density and diffusivity of silk hydrogels with respect to protein concentration and crosslink reagent concentration. This work demonstrates the tunable diffusivity and crosslinking in silk fibroin hydrogels, and enables the rational design of biomaterials. Further, the characterization methods

  17. The metapleural gland of ants

    DEFF Research Database (Denmark)

    Yek, Sze Huei; Mueller, Ulrich G

    2011-01-01

    The metapleural gland (MG) is a complex glandular structure unique to ants, suggesting a critical role in their origin and ecological success. We synthesize the current understanding of the adaptive function, morphology, evolutionary history, and chemical properties of the MG. Two functions......-compressible invagination of the integument and the secretion is thought to ooze out passively through the non-closable opening of the MG or is groomed off by the legs and applied to target surfaces. MG loss has occurred repeatedly among the ants, particularly in the subfamilies Formicinae and Myrmicinae, and the MG...... is more commonly absent in males than in workers. MG chemistry has been characterized mostly in derived ant lineages with unique biologies (e.g. leafcutter ants, fire ants), currently precluding any inferences about MG chemistry at the origin of the ants. A synthetic approach integrating functional...

  18. Determination of Antimicrobial Activity of the Dyed Silk Fabrics with Some Natural Dyes

    OpenAIRE

    ALKAN, Rezan; TORGAN, Emine; AYDIN, Canan; KARADAG, Recep

    2015-01-01

    In this study, silk fabric is dyed with natural indigo. Dyed silk fabric with natural indigo was cut in the 20x20 cm2 size. Excluding a fabric, all fabrics were mordanted in the same percentage with alum metal (KAl(SO4)2.12H2O). Then, silk fabrics for green color dyeing are dyed separately with weld (Reseda luteola), gall oak (Quercus infectoria Olivier) and together weld (Reseda luteola) and gall oak (Quercus infectoria) in different percentage. Antimicrobial functionality of the twenty seve...

  19. China and megaregional integration: the New Maritime Silk Road in Africa

    Directory of Open Access Journals (Sweden)

    Manuel de Jesús Rocha Pino

    2016-12-01

    Full Text Available This article examines the China’s Belt and Road (B&R trade and investment initiative. The B&R concept is formed of two projects: the Silk Road Economic Belt and the New Maritime Silk Road. This study focusses, specifically, on the range of implementation of the New Maritime Silk Road in Africa. For this, two variables are analysed that could be decisive in this process: the current regionalism trend of establishing megaregional free trade agreements and the agenda for domestic economic reform in China.

  20. Preparation and properties of silk sericin/cellulose cross-linking films

    Directory of Open Access Journals (Sweden)

    Wang Kunyan

    2017-01-01

    Full Text Available Silk sericin/cellulose cross-linked films were successfully prepared using glutaraldehyde as cross-linkinger. FTIR was applied to characterize the chemical structure of films. Cross-linked silk sericin film was found the peak intensity of FTIR for cross-linked film decreased markedly compared to pure silk sericin, which indicating cross-linking reaction has been occurred. The increasing value of swelling ratio also indicated the cross-linking has been happened. The cross-linking reaction increased the thermal decomposition temperature.

  1. Dissolution behavior of silk fibroin in a low concentration CaCl2-methanol solvent: From morphology to nanostructure.

    Science.gov (United States)

    Shen, Tingting; Wang, Tao; Cheng, Guotao; Huang, Lan; Chen, Lei; Wu, Dayang

    2018-02-05

    Regenerated Silk biomaterials are usually pre-formed from silk fibroin solutions. However, the dissolution of silk fibroin in proper solvents by a simple and low cost way is still a challenge. Here, we employed a CaCl 2 -methanol solvent system with a very low CaCl 2 concentration of 6wt% to dissolve silk fibroin. During the dissolution process, the evaporation of methanol cause the changing of solvation sheath of ions in the solvent. The remaining solvent with the incomplete solvation sheath is absorbed by the silk fiber and interacts with fibroin chains to complete the solvation sheath, which accounts for the dissolution of silk fibroin. Silk fibroin dissolution stops as all the solvation sheaths are complete. The final CaCl 2 concentration is ca. 26% and silk fibroin is completely dissolved with a yield of about 90%. Silk fibroin is dissolved into multi-scale nanofibrils solution which is potential for producing regenerated silk fibroin materials for functional applications. Copyright © 2018. Published by Elsevier B.V.

  2. Phononic band gap and mechanical anisotropy in spider silk

    Science.gov (United States)

    Papadopoulos, Periklis; Gomopoulos, Nikos; Kremer, Friedrich; Fytas, George

    2010-03-01

    Spider dragline silk is a semi-crystalline biopolymer exhibiting superior properties compared to synthetic polymers with similar chemical structure, such as polyamides. This is ascribed to the hierarchical nanostructure that is created in the spinning duct. During this process the aqueous solution of the two protein constituents of dragline silk is crystallized, while the macromolecules maintain their high orientation, leading to a high value of the Young's modulus (in the order of 10 GPa) along the fiber. We employed spontaneous Brillouin light scattering to measure the longitudinal modulus (M//,,M) along the two symmetry directions of the native fiber with increased (decreased) pre-strain created by stretching (supercontracting after hydration). A strong mechanical anisotropy is found; at about 18% strain M///M˜5. Most important, an unexpected finding is the first observation of a unidirectional hypersonic phononic band gap in biological structures. This relates to the existence of a strain-dependent correlation length of the mechanical modulus in the submicron range along the fiber axis.

  3. Nanofibrous nonmulberry silk/PVA scaffold for osteoinduction and osseointegration.

    Science.gov (United States)

    Bhattacharjee, Promita; Kundu, Banani; Naskar, Deboki; Maiti, Tapas K; Bhattacharya, Debasis; Kundu, Subhas C

    2015-05-01

    Poly-vinyl alcohol and nonmulberry tasar silk fibroin of Antheraea mylitta are blended to fabricate nanofibrous scaffolds for bone regeneration. Nanofibrous matrices are prepared by electrospinning the equal volume ratio blends of silk fibroin (2 and 4 wt%) with poly-vinyl alcohol solution (10 wt%) and designated as 2SF/PVA and 4SF/PVA, respectively with average nanofiber diameters of 177 ± 13 nm (2SF/PVA) and 193 ± 17 nm (4SF/PVA). Fourier transform infrared spectroscopy confirms retention of the secondary structure of fibroin in blends indicating the structural stability of neo-matrix. Both thermal stability and contact angle of the blends decrease with increasing fibroin percentage. Conversely, fibroin imparts mechanical stability to the blends; greater tensile strength is observed with increasing fibroin concentration. Blended scaffolds are biodegradable and support well the neo-bone matrix synthesis by human osteoblast like cells. The findings indicate the potentiality of nanofibrous scaffolds of nonmulberry fibroin as bone scaffolding material. © 2014 Wiley Periodicals, Inc.

  4. Silk Fibroin/Polyvinyl Pyrrolidone Interpenetrating Polymer Network Hydrogels

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    Dajiang Kuang

    2018-02-01

    Full Text Available Silk fibroin hydrogel is an ideal model as biomaterial matrix due to its excellent biocompatibility and used in the field of medical polymer materials. Nevertheless, native fibroin hydrogels show poor transparency and resilience. To settle these drawbacks, an interpenetrating network (IPN of hydrogels are synthesized with changing ratios of silk fibroin/N-Vinyl-2-pyrrolidonemixtures that crosslink by H2O2 and horseradish peroxidase. Interpenetrating polymer network structure can shorten the gel time and the pure fibroin solution gel time for more than a week. This is mainly due to conformation from the random coil to the β-sheet structure changes of fibroin. Moreover, the light transmittance of IPN hydrogel can be as high as more than 97% and maintain a level of 90% within a week. The hydrogel, which mainly consists of random coil, the apertures inside can be up to 200 μm. Elastic modulus increases during the process of gelation. The gel has nearly 95% resilience under the compression of 70% eventually, which is much higher than native fibroin gel. The results suggest that the present IPN hydrogels have excellent mechanical properties and excellent transparency.

  5. Gender inequality and entrepreneurship: the Indian silk industry.

    Science.gov (United States)

    Mayoux, L

    1993-12-01

    The production of raw silk yarns from cocoons (reeling) is a crucial middle stage in the silk industry. The author reviews the experience of attempts to encourage women's entrepreneurship in this industry in Karnataka, South India. Reeling is a potentially lucrative field with possibilities for upward mobility from small-scale to large-scale production if credit is readily available. The industry in India employs large numbers of skilled female workers from all communities and is one of few in which a sectoral gender policy is being implemented. While these factors may be thought to be conducive to the development of women entrepreneurs, none were in the areas studied at the time of research. No women were involved in marketing through the official marketing system and no women's co-operatives were operating. While women were listed among registered reelers, men controlled the businesses. Men simply used women to obtain supplementary bank loans or funds through other avenues otherwise open to only women. Policies for women in reeling have therefore proved to be overwhelmingly unsuccessful. The author considers gender inequality and gender policy at length in this context and concludes that the problem is systemic and structural in nature. Policy implications are considered.

  6. Bioengineered Lacrimal Gland Organ Regeneration in Vivo

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    Masatoshi Hirayama

    2015-07-01

    Full Text Available The lacrimal gland plays an important role in maintaining a homeostatic environment for healthy ocular surfaces via tear secretion. Dry eye disease, which is caused by lacrimal gland dysfunction, is one of the most prevalent eye disorders and causes ocular discomfort, significant visual disturbances, and a reduced quality of life. Current therapies for dry eye disease, including artificial tear eye drops, are transient and palliative. The lacrimal gland, which consists of acini, ducts, and myoepithelial cells, develops from its organ germ via reciprocal epithelial-mesenchymal interactions during embryogenesis. Lacrimal tissue stem cells have been identified for use in regenerative therapeutic approaches aimed at restoring lacrimal gland functions. Fully functional organ replacement, such as for tooth and hair follicles, has also been developed via a novel three-dimensional stem cell manipulation, designated the Organ Germ Method, as a next-generation regenerative medicine. Recently, we successfully developed fully functional bioengineered lacrimal gland replacements after transplanting a bioengineered organ germ using this method. This study represented a significant advance in potential lacrimal gland organ replacement as a novel regenerative therapy for dry eye disease. In this review, we will summarize recent progress in lacrimal regeneration research and the development of bioengineered lacrimal gland organ replacement therapy.

  7. Dysfunctional ectopic thyroid gland: A case report

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    Stokić Edita

    2014-01-01

    Full Text Available Introduction. Lingual thyroid gland is a rare anomaly of thyroid gland development, occurring more frequently in females. If it causes local symptomatology such as dysphagia, dysphonia or dyspnea it is diagnosed in childhood, however, if it is asymptomatic it is usually diagnosed in adulthood. Case Outline. We present a 23-year-old female patient in whom we diagnosed lingual thyroid gland coincidentally during diagnostic procedures of a concomitant disease. The application of 131I scintigraphy showed an oval field of intensive accumulation of radio markers in the zone of medial face line, around tongue base, with the absence of thyroid gland in its physiological position. Functional testing proved primary hypothyroidism and we started the application of substitution therapy. The application of levothyroxine resulted in reaching euthyroid state and the reduction of thyroid gland size. Conclusion. We present a very rare anomaly of the thyroid gland, and so far there have been no clear attitudes about further treatment. The general condition of the patient, age, the size of ectopic thyroid gland and the existence of local symptomatology or complications represent the factors that have influence on the choice of treatment method.

  8. Primary parotid gland lymphoma: a case report

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    Paraskevas Katsaronis

    2011-08-01

    Full Text Available Abstract Introduction Mucosa associated lymphoid tissue lymphomas are the most common lymphomas of the salivary glands. The benign lymphoepithelial lesion is also a lymphoproliferative disease that develops in the parotid gland. In the present case report, we describe one case of benign lymphoepithelial lesion with a subsequent low transformation to grade mucosa associated lymphoid tissue lymphoma appearing as a cystic mass in the parotid gland. Case presentation A 78-year-old Caucasian female smoker was referred to our clinic with a non-tender left facial swelling that had been present for approximately three years. The patient underwent resection of the left parotid gland with preservation of the left facial nerve through a preauricular incision. The pathology report was consistent with a low-grade marginal-zone B-cell non-Hodgkin lymphoma (mucosa associated lymphoid tissue lymphoma following benign lymphoepithelial lesion of the gland. Conclusions Salivary gland mucosa associated lymphoid tissue lymphoma should be considered in the differential diagnosis of cystic or bilateral salivary gland lesions. Parotidectomy is recommended in order to treat the tumor and to ensure histological diagnosis for further follow-up planning. Radiotherapy and chemotherapy should be considered in association with surgery in disseminated forms or after removal.

  9. Thyroid Gland in Patients with Rheumatoid Arthritis

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    B T Turumhambetova

    2009-09-01

    Full Text Available The purpose of our study was to investigate the main parameters of thyroid status in patients with rheumatoid arthritis (RA, as well as particularities of course of this disease depending on of thyroid gland function disorder. Materials and methods. 52 women with RA were examined. The first group consisted of 11 women with subclinical and manifestive hypothyroidism the second one 41 women without thyroid gland function disorder. The group comparison was conducted on main indexes of thyroid gland condition the hormon level, AT-TPO, ultrasonic data, as well as clinical and laboratory RA data. Results. In women with hypothyroidism the systemic manifestations of RA were more often truely diagnosed; DAS28 indexes, ESR, the number ot swollen joints were higher. The high level ot AT-TPO was diagnosed in 54,55% – I group and in 31,7% – II group TTG level was really less in patients receiving synthetic glycocorticoids. Small thyroid gland volume was diagnosed in 23,07% of examined patients. The thyroid gland status indexes in them did not differ from patients with normal thyroid gland volume. Reliable increasing of the peripheral resistance index was revealed in lower thyroid artery according to the ultrasonic study data under the reduced thyroid gland size. Conclusions. High incidence of hypothyroidism and AT-TPO carriage in RA was revealed. Hypothyroidism development is accompanied by high clinic-laboratory RA activity. The reduction of the thyroid gland volumes in RA is possibly stipulated not only by autoimmunal pathology, but also chronic ischemia of the organ in the conditions of immune-complex vasculitis and early atherosclerosis. The TTG level in patients with RA is defined not only by pathology of the thyroid gland, but glycocorticoid therapy as well.

  10. Lymphoma type MALT of the parotid gland

    International Nuclear Information System (INIS)

    Frometa Neirai, Carlos; Gonzalez Gomez, Juan Manuel; Arredondo Lopez, Miguel

    2010-01-01

    The lymphomas type MALT or the mucosa-associated lymphoid tissue, are the most recent variety of non-Hodgkin lymphomas present mainly in the gastric mucosa associated with Helycobacter pylori infection and in the thyroid gland in relation to Hashimoto's thyroiditis. Frequently the origin of this lesion can't be determined only by cytology study, thus it is necessary the histopathology analysis for a definitive diagnosis in most cases. Present paper includes the case of male patient with bilateral volume increase of both parotid glands and a diagnosis cytopathological of a benign lymphoepithelial process and the development of a type MALT lymphoma in relation to the right parotid gland. (author)

  11. Hydatid disease of the submandibular gland

    International Nuclear Information System (INIS)

    Ullah, N.; Yousaf, N.

    2001-01-01

    Echinococcosis is a tissue infection of the human caused by the larval stage of echinococcus granulosus or E. multilocularis. Hydatid cyst of the head and neck region is uncommon and the involvement of salivary glands, especially the submandibular gland, is very rare. A case of submandibular gland hydatid cyst is reported in this article, in a patient who was presented with swelling of this area of three months' duration. Examination revealed a soft, non-tender, mobile mass measuring 6x4 cm. Chest X-ray and abdominal ultrasonography were normal. Excision of the whole mass was performed and pathological examination confirmed the fine needle aspiration cytology report. (author)

  12. [Salivary gland drainage into the thyroglossal duct].

    Science.gov (United States)

    Siem, G; Natvig, K; Kolbenstvedt, A; Lømo, J

    2001-01-20

    Failure in regression of the thyroglossal duct is one of the most common reasons for midline swellings in the neck. Several authors have described recurrent thyroglossal duct remnants with persisting draining sinuses. However, few have described accessory salivary glands that drain into the thyroglossal duct. In this article we report two such cases with midline salivary glands in the floor of the mouth. These two patients were subsequently successfully treated with radical tissue resection in the area between the hyoid bone and foramen cecum. Preoperative fistulography or sinography was useful to demonstrate the ductal ramification of the salivary glands, and use of methylene blue during surgery proved of significant value for the result.

  13. Electromechanical response of silk fibroin hydrogel and conductive polycarbazole/silk fibroin hydrogel composites as actuator material.

    Science.gov (United States)

    Srisawasdi, Thanida; Petcharoen, Karat; Sirivat, Anuvat; Jamieson, Alexander M

    2015-11-01

    Pure silk fibroin (SF) hydrogel and polycarbazole/silk fibroin (SF/PCZ) hydrogels were fabricated by solvent casting technique to evaluate electromechanical responses, dielectric properties, and cantilever deflection properties as functions of electric field strength, SF concentration, glutaraldehyde concentration, and PCZ concentration in the blends. Electromechanical properties were characterized in oscillatory shear mode at electric field strengths ranging from 0 to 600V/mm and at a temperature of 27°C. For both the pristine SF and SF/PCZ hydrogels, the storage modulus response (ΔG') and the storage modulus sensitivity (ΔG'/G'0) increased dramatically with increasing electric field strength. The pristine hydrogel possessed the highest storage modulus sensitivity value of 5.87, a relatively high value when compared with other previously studied electroactive polymers. With the addition of conductive PCZ in SF hydrogel, the storage modulus sensitivity and the relative dielectric constant decreased; the conductive polymer thus provided the softening effect under electric field. In the deflection response, the dielectrophoresis force and deflection distance increased monotonically with electric field strength, where the pure SF hydrogel showed the highest deflection distance and dielectrophoresis force. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. [Description of Melolonthidae (Coleoptera) third instar larvae associated to Agave tequilana var. Azul and their population fluctuation in Jalisco, Mexico].

    Science.gov (United States)

    García, Gabriel L; Ortega-Arenas, Laura; Hernández, Héctor G; García, Agustín A; Nápoles, Jesús R; Cortés, Ramón R

    2009-01-01

    Third instars of white grubs of six species associated to agave tequilero in Jalisco, México were described from 1,145 specimens collected from soil samples from September 2006 to August 2007, in the municipalities of Ixtlahuacán del Río, Tepatitlán de Morelos and San Juan de Escobedo, Jalisco, México. Diagnostic characters were illustrated and a key was also included. Cyclocephala comata (Bates) was the most abundant species (63.2%), followed by Phyllophaga ravida (Blanchard) (21.9%), Phyllophaga polyphylla (Bates) (9.4%), Phyllophaga misteca (Bates) (4.1%), Strategus aloeus (L.) (1.1%) and Anomala hoepfneri (Bates) (0.3%). Phyllophaga ravida and A. hoepfneri are reported for the first time on the agave plant and the latter is a new record for the State of Jalisco. All Melolonthidae species showed a marked seasonality with lower number of larvae in June 2007 and high number in August 2007, which is associated with the region's rainy season and the agave plant age, respectively.

  15. Eco-friendly synthesis of silver nanoparticles and its larvicidal property against fourth instar larvae of Aedes aegypti.

    Science.gov (United States)

    Ali, Zainal Abidin; Roslan, Muhammad Aidil; Yahya, Rosiyah; Wan Sulaiman, Wan Yusoff; Puteh, Rustam

    2017-03-01

    In this study, larvicidal activity of silver nanoparticles (AgNPs) synthesised using apple extract against fourth instar larvae of Aedes aegypti was determined. As a result, the AgNPs showed moderate larvicidal effects against Ae. aegypti larvae (LC 50  = 15.76 ppm and LC 90  = 27.7 ppm). In addition, comparison of larvicidal activity performance of AgNPs at high concentration prepared using two different methods showed that Ae. aegypti larvae was fully eliminated within the duration of 2.5 h. From X-ray diffraction, the AgNP crystallites were found to exhibit face centred cubic structure. The average size of these AgNPs as estimated by particle size distribution was in the range of 50-120 nm. The absorption maxima of the synthesised Ag showed characteristic Ag surface plasmon resonance peak. This green synthesis provides an economic, eco-friendly and clean synthesis route to Ag.

  16. Ultrastructure of the ovary of Dermatobia hominis (Diptera: cuterebridae. I. Development during the 3rd larval instar

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    E. A. Gregorio

    1990-09-01

    Full Text Available The ultrastructure and distribution of gonial and somatic cells in the ovary of Dermatobia hominis was studied during the 3rd larval instar. In larvae weighing between 400 and 500 mg, the ovary is partially divided into basal and apical regions by oblong somatic cells that penetrate from the periphery; these cells show ovoid nucleus and cytoplasm full of microtubules. In both regions, gonial cells with regular outlines, large nucleus and low electron-density cytoplasm are scattered among the interstitial somatic cells. These later cells have small nucleus and electrodense cytoplasm. Clear somatic cells with small nucleus and cytoplasm of very low electron-density are restrict to the apical region of the gonad. Degenerating interstitial somatic cells are seen in the basal portion close to the ovary peduncle. During all this larval period the morphological features of the ovary remain almost the same. At the end of the period there is a gradual deposition of glycogen in the cytoplasm of the somatic cells, increase in the number and density of their mitochondria plus nuclear modification as membrane wrinkling and chromatin condensation in masses.

  17. Selection of reference genes for tissue/organ samples on day 3 fifth-instar larvae in silkworm, Bombyx mori.

    Science.gov (United States)

    Wang, Genhong; Chen, Yanfei; Zhang, Xiaoying; Bai, Bingchuan; Yan, Hao; Qin, Daoyuan; Xia, Qingyou

    2018-06-01

    The silkworm, Bombyx mori, is one of the world's most economically important insect. Surveying variations in gene expression among multiple tissue/organ samples will provide clues for gene function assignments and will be helpful for identifying genes related to economic traits or specific cellular processes. To ensure their accuracy, commonly used gene expression quantification methods require a set of stable reference genes for data normalization. In this study, 24 candidate reference genes were assessed in 10 tissue/organ samples of day 3 fifth-instar B. mori larvae using geNorm and NormFinder. The results revealed that, using the combination of the expression of BGIBMGA003186 and BGIBMGA008209 was the optimum choice for normalizing the expression data of the B. mori tissue/organ samples. The most stable gene, BGIBMGA003186, is recommended if just one reference gene is used. Moreover, the commonly used reference gene encoding cytoplasmic actin was the least appropriate reference gene of the samples investigated. The reliability of the selected reference genes was further confirmed by evaluating the expression profiles of two cathepsin genes. Our results may be useful for future studies involving the quantification of relative gene expression levels of different tissue/organ samples in B. mori. © 2018 Wiley Periodicals, Inc.

  18. Comparative proteomics and expression analysis of five genes in Epicauta chinensis larvae from the first to fifth instar.

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    Qiurong Li

    Full Text Available Blister beetle is an important insect model for both medicinal and pure research. Previous research has mainly focused on its biology and biochemistry, but very little data is yet available in the molecular biology. This study uses differential proteomics technology to analyze the soluble proteins extracted from each of the 5 instars larvae of Epicauta chinensis. 42 of the differentially-expressed proteins were identified successfully by MALDI-TOF/TOF-MS. Some of these proteins' function and their expression profiles are analyzed. Our analysis revealed dynamics regulation of the following proteins: Axin-like protein pry-1 (APR-1, dihydrolipoyl dehydrogenase (DLD, vitellogenin (Vg and lysozyme C (Lmz-S. APR-1 negatively regulates the Wnt signaling pathway. Its overexpression could result in embryo, leg, eye and ovary ectopica or malformation. DLD catalyzes the pyruvate into acetyl-CoA, the latter is the starting material of juvenile hormone (JH and ipsdienol biosynthesis through the MVA pathway in insects. While Vg synthesis can be regulated by JH and stimulated by food factors. So DLD may affect the synthesis of JH, ipsdienol and Vg indirectly. The activity of lysozyme is an indicator of the immunity. Nutrition/food should be taken into account for its potential role during the development of larva in the future. Among the five genes and their corresponding proteins' expression, only hsc70 gene showed a good correspondence with the protein level. This reflects the fluctuating relationship between mRNA and protein levels.

  19. Drawing-induced changes in morphology and mechanical properties of hornet silk gel films.

    Science.gov (United States)

    Kameda, Tsunenori; Kojima, Katsura; Togawa, Eiji; Sezutsu, Hideki; Zhang, Qiang; Teramoto, Hidetoshi; Tamada, Yasushi

    2010-04-12

    Complete amino acid sequences of the four major proteins (Vssilk 1-4) of silk (hornet silk) obtained from yellow hornet ( Vespa simillima , Vespinae, Vespidae) cocoons have been determined. The native structure of the hornet silk (HS), in which Vssilk 1-4 have an alpha-helix domain with coiled-coil alpha-helices and a beta-sheet domain, is restored when hornet silk gel films (HSGFs) are formed by pressing and drying HS hydrogel. Necking occurs when dry HSGFs are drawn; however, wet HSGFs can be uniaxially drawn with a draw ratio (DR) of 2. Drawing helps obtain high-performance films with a maximum tensile strength and tensile modulus of 170 MPa and 5.5 GPa, respectively. Drawing-induced changes in the orientation and conformation of the coiled-coil structure are investigated.

  20. Conization of the cervix uteri. Complications in connection with plain catgut or silk suturing

    DEFF Research Database (Denmark)

    Holmskov, A; Qvist, N; Møller, A

    1984-01-01

    During a retrospective study on postoperative complications in 213 patients who had undergone conization, a (non-significant) reduction in the bleeding rate from 27.9% to 18.6% was found when using silk sutures (102 patients) instead of plain catgut (111 patients) for adaption of the edges...... group and 16.6% in the silk group. On the other hand, more cases of stenosis of the cervical canal were observed, i.e., 25.5% in the silk group and 8.1% in the catgut group (p less than 0.001). The period of hospitalization was reduced on an average by 2 days when using silk (p less than 0.001)....