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Exploration of the protein conformation and mechanical properties of different spider silks. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Büsse S, Büscher TH, Kelly ET, Heepe L, Edgerly JS, Gorb SN. Pressure-induced silk spinning mechanism in webspinners (Insecta: Embioptera). SOFT MATTER 2019; 15:9742-9750. [PMID: 31742303 DOI: 10.1039/c9sm01782h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The articulated appendages of arthropods are highly adaptable and potentially multifunctional, used for walking, swimming, feeding, prey capture, or other functions. Webspinners (Order Embioptera) are a paragon in this context. In contrast to other arthropods producing silk, they utilize their front feet for silk production. However, employing the same leg for alternative functions rather than for pure locomotion potentially imposes constraints and compromises. We here present morphological and experimental evidence for a "passive" pressure-induced silk spinning mechanism induced by external mechanical stimuli. Furthermore, we demonstrate that, as a consequence of the conflicting functions for their front feet, webspinners have evolved a unique style of walking that reduces the potentially problematic contact between silk ejectors and the substrate. Here we answer for the first time a long-term question within this enigmatic group of insects-how webspinners can use their front feet to spin their nanoscale silk. This knowledge may open the door for experimental studies on an artificial spinning process and for future utilization in applied fields of robotics or chemistry.
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Affiliation(s)
- Sebastian Büsse
- Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Kiel, Germany.
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Szumik C, Juárez ML, Ramirez MJ, Goloboff P, Pereyra VV. Implications of the Tympanal Hearing Organ and Ultrastructure of Chaetotaxy for the Higher Classification of Embioptera. AMERICAN MUSEUM NOVITATES 2019. [DOI: 10.1206/3933.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Claudia Szumik
- Unidad Ejecutora Lillo, Consejo Nacional de Investigaciones Científicas y Técnicas, Tucumán, Argentina
| | - María Laura Juárez
- Unidad Ejecutora Lillo, Consejo Nacional de Investigaciones Científicas y Técnicas, Tucumán, Argentina
| | - Martín J. Ramirez
- División Aracnología, Museo Argentino de Ciencias Naturales, Buenos Aires, Argentina
| | - Pablo Goloboff
- Unidad Ejecutora Lillo, Consejo Nacional de Investigaciones Científicas y Técnicas, Tucumán, Argentina
| | - Verónica V. Pereyra
- Unidad Ejecutora Lillo, Consejo Nacional de Investigaciones Científicas y Técnicas, Tucumán, Argentina
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Stokes GY, DiCicco EN, Moore TJ, Cheng VC, Wheeler KY, Soghigian J, Barber RP, Edgerly JS. Structural and wetting properties of nature's finest silks (order Embioptera). ROYAL SOCIETY OPEN SCIENCE 2018; 5:180893. [PMID: 30839723 PMCID: PMC6170577 DOI: 10.1098/rsos.180893] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 08/13/2018] [Indexed: 06/09/2023]
Abstract
Insects from the order Embioptera (webspinners) spin silk fibres which are less than 200 nm in diameter. In this work, we characterized and compared the diameters of single silk fibres from nine species-Antipaluria urichi, Pararhagadochir trinitatis, Saussurembia calypso, Diradius vandykei, Aposthonia ceylonica, Haploembia solieri, H. tarsalis, Oligotoma nigra and O. saundersii. Silk from seven of these species have not been previously quantified. Our studies cover five of the 10 named taxonomic families and represent about one third of the known taxonomic family-level diversity in the order Embioptera. Naturally spun silk varied in diameter from 43.6 ± 1.7 nm for D. vandykei to 122.4 ± 3.2 nm for An. urichi. Mean fibre diameter did not correlate with adult female body length. Fibre diameter is more similar in closely related species than in more distantly related species. Field observations indicated that silk appears shiny and smooth when exposed to rainwater. We therefore measured contact angles to learn more about interactions between silk and water. Higher contact angles were measured for silks with wider fibre diameter and higher quantity of hydrophobic amino acids. High static contact angles (ranging up to 122° ± 3° for An. urichi) indicated that silken sheets spun by four arboreal, webspinner species were hydrophobic. A second contact angle measurement made on a previously wetted patch of silk resulted in a lower contact angle (average difference was greater than 27°) for all four species. Our studies suggest that silk fibres which had been previously exposed to water exhibited irreversible changes in hydrophobicity and water adhesion properties. Our results are in alignment with the 'super-pinning' site hypothesis by Yarger and co-workers to describe the hydrophobic, yet water adhesive, properties exhibited by webspinner silk fibres. The physical and chemical insights gained here may inform the synthesis and development of smaller diameter silk fibres with unique water adhesion properties.
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Affiliation(s)
- Grace Y. Stokes
- Department of Chemistry & Biochemistry, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053, USA
| | - Evangelea N. DiCicco
- Department of Physics and Center for Nanostructures, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053, USA
| | - Trevor J. Moore
- Department of Chemistry & Biochemistry, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053, USA
| | - Vivian C. Cheng
- Department of Biology, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053, USA
| | - Kira Y. Wheeler
- Department of Physics and Center for Nanostructures, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053, USA
| | - John Soghigian
- Department of Environmental Sciences, The Connecticut Agricultural Experiment Station, New Haven, CT, USA
| | - Richard P. Barber
- Department of Physics and Center for Nanostructures, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053, USA
| | - Janice S. Edgerly
- Department of Biology, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053, USA
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Blamires SJ, Blackledge TA, Tso IM. Physicochemical Property Variation in Spider Silk: Ecology, Evolution, and Synthetic Production. ANNUAL REVIEW OF ENTOMOLOGY 2017; 62:443-460. [PMID: 27959639 DOI: 10.1146/annurev-ento-031616-035615] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The unique combination of great stiffness, strength, and extensibility makes spider major ampullate (MA) silk desirable for various biomimetic and synthetic applications. Intensive research on the genetics, biochemistry, and biomechanics of this material has facilitated a thorough understanding of its properties at various levels. Nevertheless, methods such as cloning, recombination, and electrospinning have not successfully produced materials with properties as impressive as those of spider silk. It is nevertheless becoming clear that silk properties are a consequence of whole-organism interactions with the environment in addition to genetic expression, gland biochemistry, and spinning processes. Here we assimilate the research done and assess the techniques used to determine distinct forms of spider silk chemical and physical property variability. We suggest that more research should focus on testing hypotheses that explain spider silk property variations in ecological and evolutionary contexts.
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Affiliation(s)
- Sean J Blamires
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan;
- Evolution & Ecology Research Centre, School of Biological, Earth & Environmental Sciences, The University of New South Wales, Sydney 2052, Australia;
| | - Todd A Blackledge
- Department of Biology, Integrated Bioscience Program, The University of Akron, Akron, Ohio 44325;
| | - I-Min Tso
- Department of Life Science, Tunghai University, Taichung 40704, Taiwan;
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Identification and bioactivity evaluation of the first neuropeptide from the lesser-known insect order Embioptera (webspinner). Amino Acids 2016; 48:1677-84. [DOI: 10.1007/s00726-016-2229-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 04/01/2016] [Indexed: 11/28/2022]
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McMillan D, Hohu K, Edgerly JS. Choreography of silk spinning by webspinners (Insecta: Embioptera) reflects lifestyle and hints at phylogeny. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12749] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David McMillan
- Department of Biology; Santa Clara University; Santa Clara CA USA
| | - Kyle Hohu
- Department of Biology; Santa Clara University; Santa Clara CA USA
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Addison JB, Popp TMO, Weber WS, Edgerly JS, Holland GP, Yarger JL. Structural characterization of nanofiber silk produced by embiopterans (webspinners). RSC Adv 2014; 4:41301-41313. [PMID: 25383190 DOI: 10.1039/c4ra07567f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Embiopterans produce silken galleries and sheets using exceptionally fine silk fibers in which they live and breed. In this study, we use electron microscopy (EM), Fourier-transform infrared (FT-IR) spectroscopy, wide angle X-ray diffraction (WAXD) and solid-state nuclear magnetic resonance (ssNMR) techniques to elucidate the molecular level protein structure of webspinner (embiid) silks. Silks from two species Antipaluria urichi and Aposthonia ceylonica are studied in this work. Electron microscopy images show that the fibers are about 90-100 nm in diameter, making webspinner silks among the finest of all known animal silks. Structural studies reveal that the silk protein core is dominated by β-sheet structures, and that the protein core is coated with a hydrophobic alkane-rich surface coating. FTIR spectra of native embiid silk shows characteristic alkane CH2 stretchings near 2800-2900 cm-1, which decrease approximately 50% after washing the silk with 2 : 1 CHCl3 : MeOH. Furthermore, 13C ssNMR data shows a significant CH2 resonance that is strongly affected by the presence of water, supporting the idea that the silk fibers are coated with a hydrocarbon-rich layer. Such a layer is likely used to protect the colonies from rain. FTIR data also suggests that embiid silks are dominated by β-sheet secondary structures similar to spider and silkworm silk fibers. NMR data confirms the presence of β-sheet nanostructures dominated by serine-rich repetitive regions. A deconvolution of the serine Cβ NMR resonance reveals that approximately 70% of all seryl residues exist in a β-sheet structure. This is consistent with WAXD results that suggest webspinner silks are 70% crystalline, which is the highest crystalline fraction reported for any animal silks. The work presented here provides a molecular level structural picture of silk fibers produced by webspinners.
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Affiliation(s)
- J Bennett Addison
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA
| | - Thomas M Osborn Popp
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA
| | - Warner S Weber
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA
| | - Janice S Edgerly
- Department of Biology, Santa Clara University, Santa Clara, CA, USA
| | - Gregory P Holland
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA
| | - Jeffery L Yarger
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, USA
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Proaño CB, Cruz S, McMillan DM, Edgerly JS. Exploration of substrate vibrations as communication signals in a webspinner from Ecuador (Embioptera: Clothodidae). NEOTROPICAL ENTOMOLOGY 2012; 41:196-203. [PMID: 23950043 DOI: 10.1007/s13744-012-0034-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 03/19/2012] [Indexed: 06/02/2023]
Abstract
Embiopterans are among the least known of all insect orders, and yet their behavior is worthy of investigation for many reasons. They spin silk produced in glands in their front tarsi and live in groups, usually mothers with their young and sometimes in large colonies with many reproductive females sharing the silk. We discovered a large embiid (Clothodidae) in an Ecuadorian rain forest living under camouflaged silk sheets spun onto the bark of trees. Observations in previous studies of a related Trinidadian clothodid revealed that individuals shake and lunge their bodies in response to intruders of their silk domicile. We took the opportunity afforded by the discovery of the large clothodids to rear them in the laboratory and to investigate their communication behavior. We used piezoelectric film to detect substrate vibrations generated by adult females as elicited by a variety of intruders (an artificial stimulus, conspecific female or male, or a female of different species of webspinners). The residents produced three signals distinguishable by behavioral action, frequency (hertz), pulses per bout, and amplitude at peak frequency. We designated these as lift silk, shake, and snapback. Shakes varied the most in amplitude and frequency in response to the different intruders, and therefore, we propose that shakes may transmit the most information as individuals contact each other. This is the first report to characterize spectral qualities and contexts of substrate vibrations in an embiopteran.
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Affiliation(s)
- C B Proaño
- Lab de Ecología y Comportamiento, Univ San Francisco de Quito, Quito, Ecuador
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Collin MA, Edgerly JS, Hayashi CY. Comparison of fibroin cDNAs from webspinning insects: insight into silk formation and function. ZOOLOGY 2011; 114:239-46. [PMID: 21741226 DOI: 10.1016/j.zool.2011.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 01/20/2011] [Accepted: 01/23/2011] [Indexed: 10/18/2022]
Abstract
Embiopterans (webspinning insects) are renowned for their prolific use of silk. These organisms spin silk to construct elaborate networks of tubes in which they live, forage, and reproduce. The silken galleries are essential for protecting these soft-bodied insects from predators and other environmental hazards. Despite the ecological importance of embiopteran silk, very little is known about its constituent proteins. Here, we characterize the silk protein cDNAs from four embiopteran species to better understand the function and evolution of these adaptive molecules. We show that webspinner fibroins (silk proteins) are highly repetitive in sequence and possess several conserved characteristics, despite differences in habitat preferences across species. The most striking similarities are in the codon usage biases of the fibroin genes, particularly in the repetitive regions, as well as sequence conservation of the carboxyl-terminal regions of the fibroins. Based on analyses of the silk genes, we propose hypotheses regarding codon bias and its effect on the translation and replication of these unusual genes. Furthermore, we discuss the significance of specific fibroin motifs to the mechanical and structural characteristics of silk fibers. Lastly, we report that the conservation of webspinner fibroin carboxyl-terminal regions suggests that fiber formation may occur through a mechanism analogous to that found in Lepidoptera. From these results, insight is gained into the tempo and mode of evolution that has shaped embiopteran fibroins.
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Affiliation(s)
- Matthew A Collin
- Department of Biology, University of California, Riverside, CA 92521, USA.
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