scholarly journals Sequence Capture Phylogenomics of True Spiders Reveals Convergent Evolution of Respiratory Systems

2020 ◽  
Vol 70 (1) ◽  
pp. 14-20 ◽  
Author(s):  
Martín J Ramírez ◽  
Ivan L F Magalhaes ◽  
Shahan Derkarabetian ◽  
Joel Ledford ◽  
Charles E Griswold ◽  
...  
Keyword(s):  
Character Evolution ◽  
Silk Gland ◽  
Published Data ◽  
Spider Web ◽  
Book Lungs ◽  
Character System ◽  
Silk Glands ◽  
Genomic Scale ◽  
Respiratory Systems ◽  
Web Building

Abstract The common ancestor of spiders likely used silk to line burrows or make simple webs, with specialized spinning organs and aerial webs originating with the evolution of the megadiverse “true spiders” (Araneomorphae). The base of the araneomorph tree also concentrates the greatest number of changes in respiratory structures, a character system whose evolution is still poorly understood, and that might be related to the evolution of silk glands. Emphasizing a dense sampling of multiple araneomorph lineages where tracheal systems likely originated, we gathered genomic-scale data and reconstructed a phylogeny of true spiders. This robust phylogenomic framework was used to conduct maximum likelihood and Bayesian character evolution analyses for respiratory systems, silk glands, and aerial webs, based on a combination of original and published data. Our results indicate that in true spiders, posterior book lungs were transformed into morphologically similar tracheal systems six times independently, after the evolution of novel silk gland systems and the origin of aerial webs. From these comparative data, we put forth a novel hypothesis that early-diverging web-building spiders were faced with new energetic demands for spinning, which prompted the evolution of similar tracheal systems via convergence; we also propose tests of predictions derived from this hypothesis.[Book lungs; discrete character evolution; respiratory systems; silk; spider web evolution; ultraconserved elements.]

scholarly journals Shifts in morphology, gene expression, and selection underlie web loss in Hawaiian Tetragnatha spiders

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Cory A. Berger ◽  
Michael S. Brewer ◽  
Nobuaki Kono ◽  
Hiroyuki Nakamura ◽  
Kazuharu Arakawa ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Adaptive Traits ◽  
Deep Time ◽  
Selective Pressures ◽  
Silk Production ◽  
Silk Glands ◽  
Genetic Mechanisms ◽  
Orb Web ◽  
Short Time ◽  
Web Building

Abstract Background A striking aspect of evolution is that it often converges on similar trajectories. Evolutionary convergence can occur in deep time or over short time scales, and is associated with the imposition of similar selective pressures. Repeated convergent events provide a framework to infer the genetic basis of adaptive traits. The current study examines the genetic basis of secondary web loss within web-building spiders (Araneoidea). Specifically, we use a lineage of spiders in the genus Tetragnatha (Tetragnathidae) that has diverged into two clades associated with the relatively recent (5 mya) colonization of, and subsequent adaptive radiation within, the Hawaiian Islands. One clade has adopted a cursorial lifestyle, and the other has retained the ancestral behavior of capturing prey with sticky orb webs. We explore how these behavioral phenotypes are reflected in the morphology of the spinning apparatus and internal silk glands, and the expression of silk genes. Several sister families to the Tetragnathidae have undergone similar web loss, so we also ask whether convergent patterns of selection can be detected in these lineages. Results The cursorial clade has lost spigots associated with the sticky spiral of the orb web. This appears to have been accompanied by loss of silk glands themselves. We generated phylogenies of silk proteins (spidroins), which showed that the transcriptomes of cursorial Tetragnatha contain all major spidroins except for flagelliform. We also found an uncharacterized spidroin that has higher expression in cursorial species. We found evidence for convergent selection acting on this spidroin, as well as genes involved in protein metabolism, in the cursorial Tetragnatha and divergent cursorial lineages in the families Malkaridae and Mimetidae. Conclusions Our results provide strong evidence that independent web loss events and the associated adoption of a cursorial lifestyle are based on similar genetic mechanisms. Many genes we identified as having evolved convergently are associated with protein synthesis, degradation, and processing, which are processes that play important roles in silk production. This study demonstrates, in the case of independent evolution of web loss, that similar selective pressures act on many of the same genes to produce the same phenotypes and behaviors.

scholarly journals Distinct movement patterns generate stages of spider web building

2021 ◽  
Author(s):  
Abel Corver ◽  
Nicholas Wilkerson ◽  
Jeremiah Miller ◽  
Andrew Gordus
Keyword(s):  
Movement Patterns ◽  
Spider Web ◽  
Web Building

scholarly journals Adhesion enhancement of cribellate capture threads by epicuticular waxes of the insect prey sheds new light on spider web evolution

2017 ◽  
Vol 284 (1855) ◽  
pp. 20170363 ◽  
Author(s):  
Raya A. Bott ◽  
Werner Baumgartner ◽  
Peter Bräunig ◽  
Florian Menzel ◽  
Anna-Christin Joel
Keyword(s):  
Adhesive Force ◽  
Arms Race ◽  
Epicuticular Waxes ◽  
Cuticular Waxes ◽  
Free Surfaces ◽  
Spider Web ◽  
Insect Prey ◽  
Reinforced Composite ◽  
Artificial Surfaces ◽  
Web Building

To survive, web-building spiders rely on their capture threads to restrain prey. Many species use special adhesives for this task, and again the majority of those species cover their threads with viscoelastic glue droplets. Cribellate spiders, by contrast, use a wool of nanofibres as adhesive. Previous studies hypothesized that prey is restrained by van der Waals' forces and entrapment in the nanofibres. A large discrepancy when comparing the adhesive force on artificial surfaces versus prey implied that the real mechanism was still elusive. We observed that insect prey's epicuticular waxes infiltrate the wool of nanofibres, probably induced by capillary forces. The fibre-reinforced composite thus formed led to an adhesion between prey and thread eight times stronger than that between thread and wax-free surfaces. Thus, cribellate spiders employ the originally protective coating of their insect prey as a fatal component of their adhesive and the insect promotes its own capture. We suggest an evolutionary arms race with prey changing the properties of their cuticular waxes to escape the cribellate capture threads that eventually favoured spider threads with viscous glue.

scholarly journals A Targeted In-Fusion Expression System for Recombinant Protein Production in Bombyx mori

2022 ◽  
Vol 12 ◽  
Author(s):  
Zhiqian Li ◽  
Lang You ◽  
Qichao Zhang ◽  
Ye Yu ◽  
Anjiang Tan
Keyword(s):  
Bombyx Mori ◽  
Recombinant Proteins ◽  
Expression System ◽  
Silk Gland ◽  
Fusion Expression ◽  
Transcription Activator ◽  
Genomic Locus ◽  
Silk Proteins ◽  
Silk Glands ◽  
New Strategy

The domesticated silkworm, Bombyx mori, is an economically important insect that synthesizes large amounts of silk proteins in its silk gland to make cocoons. In recent years, germline transformation strategies advanced the bioengineering of the silk gland as an ideal bioreactor for mass production of recombinant proteins. However, the yield of exogenous proteins varied largely due to the random insertion and gene drift caused by canonical transposon-based transformation, calling for site-specific and stable expression systems. In the current study, we established a targeted in-fusion expression system by using the transcription activator-like effector nuclease (TALEN)-mediated targeted insertion to target genomic locus of sericin, one of the major silk proteins. We successfully generated chimeric Sericin1-EGFP (Ser-2A-EGFP) transformant, producing up to 3.1% (w/w) of EGFP protein in the cocoon shell. With this strategy, we further expressed the medically important human epidermal growth factor (hEGF) and the protein yield in both middle silk glands, and cocoon shells reached to more than 15-fold higher than the canonical piggyBac-based transgenesis. This natural Sericin1 expression system provides a new strategy for producing recombinant proteins by using the silkworm silk gland as the bioreactor.

TREHALASE ACTIVITY IN THE SILK GLANDS OF THE SILKWORM, BOMBYX MORI (LEPIDOPTERA: BOMBYCIDAE)

1975 ◽  
Vol 107 (12) ◽  
pp. 1311-1314 ◽  
Author(s):  
Shuya Shimada
Keyword(s):  
Bombyx Mori ◽  
Divalent Cations ◽  
Silk Gland ◽  
Trehalase Activity ◽  
Gland Cells ◽  
Silk Glands ◽  
Tunica Propria ◽  
Silkworm Bombyx Mori ◽  
Cu And Zn ◽  
Tunica Intima

Abstract(1) Crude extracts prepared from the silk glands of the silkworm, Bombyx mori L. contain trehalase activity. (2) Trehalase in the silk glands has a pH of 5.5 and a Km of 0.71 mM. The activity of the enzyme is inhibited by divalent cations such as Mn, Cu, and Zn. (3) By histochemical methods, it is shown that trehalase is localized in the periphery of the silk gland cells, especially in the tunica propria and tunica intima. (4) Trehalase activity is low in fifth instar and increases greatly in spinning stages, after which the activity decreases.

scholarly journals Structure Water-Solubility Relationship in α-Helix-Rich Films Cast from Aqueous and 1,1,1,3,3,3-Hexafluoro-2-Propanol Solutions of S. c. ricini Silk Fibroin

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3945
Author(s):  
Moseti ◽  
Yoshioka ◽  
Kameda ◽  
Nakazawa
Keyword(s):  
Silk Fibroin ◽  
Water Solubility ◽  
Silk Gland ◽  
Post Treatment ◽  
Water Soluble ◽  
Cast Film ◽  
Silk Glands ◽  
Α Helix ◽  
Β Sheet ◽  
Structure Water

Silk fibroin (SF) produced by the domesticated wild silkworm, Samia cynthia ricini (S. c. ricini) is attracting increasing interest owing to its unique mechanical properties, biocompatibility, and abundance in nature. However, its utilization is limited, largely due to lack of appropriate processing strategies. Various strategies have been assessed to regenerate cocoon SF, as well as the use of aqueous liquid fibroin (LFaq) prepared by dissolution of silk dope obtained from the silk glands of mature silkworm larvae in water. However, films cast from these fibroin solutions in water or organic solvents are often water-soluble and require post-treatment to render them water-stable. Here, we present a strategy for fabrication of water-stable films from S. c. ricini silk gland fibroin (SGF) without post-treatment. Aqueous ethanol induced gelation of fibroin in the posterior silk glands (PSG), enabling its separation from the rest of the silk gland. When dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), the SGF-gel gave a solution from which a transparent, flexible, and water-insoluble film (SGFHFIP) was cast. Detailed structural characterization of the SGFHFIP as-cast film was carried out and compared to a conventional, water-soluble film cast from LFaq. FTIR and 13C solid-state NMR analyses revealed both cast films to be α-helix-rich. However, gelation of SGF induced by the 40%-EtOH-treatment resulted in an imperfect β-sheet structure. As a result, the SGF-gel was soluble in HFIP, but some β-sheet structural memory remains, and the SGFHFIP as-cast film obtained has some β-sheet content which renders it water-resistant. These results reveal a structure water-solubility relationship in S. c. ricini SF films that may offer useful insights towards tunable fabrication of novel biomaterials. A plausible model of the mechanism that leads to the difference in water resistance of the two kinds of α-helix-rich films is proposed.

scholarly journals Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

2016 ◽  
Author(s):  
Elizabeth J Roberson ◽  
Michael J Chips ◽  
Walter P Carson ◽  
Thomas P Rooney
Keyword(s):  
Vegetation Structure ◽  
Prey Availability ◽  
Forest Disturbance ◽  
Geographic Region ◽  
Spider Webs ◽  
Spider Web ◽  
Food Web Interactions ◽  
Closed Canopy ◽  
Availability Index ◽  
Web Building

Indirect effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in Pennsylvania and Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Wisconsin sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7-12 times greater in deer-free plots. Prey availability was also higher in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread throughout the region.

Tanned silks

1974 ◽  
Vol 187 (1087) ◽  
pp. 133-170 ◽  
Keyword(s):  
Phenolic Compounds ◽  
Silk Gland ◽  
Oxidation Products ◽  
Gentisic Acid ◽  
Silk Glands ◽  
Cross Links ◽  
The Subject ◽  
Hydroxyanthranilic Acid ◽  
Physical And Chemical ◽  
Natural Metabolite

The silks of the large cocoons of saturniid moths range in colour from pale to dark brown. They are invariably accompanied by phenolic compounds. The nature of these phenols and their interaction with silk form the subject of this paper. Silk, though fluid when secreted, dries out almost instantly. It is pure white; and if artificially kept dry remains white. If the larva is allowed (as is in normal) to drench it with a watery secretion from the anus, or if artificially moistened, it darkens. Saturniid silks are here shown to consist, not only of structural fibroin and sericin, but also of enzymes and phenols. The presence of moisture allows these to interact. The phenols in the silk gland are in the form of glucosides. They are cleaved by a glucosidase and the liberated phenols are then oxidized by an oxidase. The oxidation products act as tanning agents supposedly by introducing exogenous cross-links between protein chains. Tanning brings about considerable physical and chemical changes in the properties of the silk. These are described. Two of the tanning phenols have been identified. The O -glucoside of 3-hydroxyanthranilic acid has not been previously recorded as a natural metabolite of animals or plants (although it is said to appear in the excreta of Bombyx larvae following enforced administration of 3-hydroxyanthranilic acid). The 5- O -glucoside of gentisic acid has not been recorded in animals but has been found in boron-deficient plants. The identity of both has been confirmed by synthesis. 3-Hydroxyanthranilic acid glucoside is derived from dietary tryptophan, but gentisic acid does not arise from an aromatic amino acid. Our evidence is consistent with its being taken up from the food-plant as a conjugate, and with the phenolic moiety being used, without change, by the silk glands. The biological and industrial implications of tanning of the cocoon silk are briefly considered.

Using spider web types as a substitute for assessing web-building spider biodiversity and the success of habitat restoration

2010 ◽  
Vol 19 (11) ◽  
pp. 3141-3155 ◽  
Author(s):  
John R. Gollan ◽  
Helen M. Smith ◽  
Matthew Bulbert ◽  
Andrew P. Donnelly ◽  
Lance Wilkie
Keyword(s):  
Habitat Restoration ◽  
Spider Web ◽  
Web Building

scholarly journals Dynamic environments do not appear to constrain spider web building behaviour

2021 ◽  
Vol 108 (3) ◽  
Author(s):  
Tom Mulder ◽  
Lucas Wilkins ◽  
Beth Mortimer ◽  
Fritz Vollrath
Keyword(s):  
Wind Loading ◽  
Spider Webs ◽  
Spider Web ◽  
Thread Tension ◽  
In The Wild ◽  
Orb Web ◽  
Araneus Diadematus ◽  
Orb Web Spiders ◽  
Building Behaviour ◽  
Web Building

AbstractMany laboratory experiments demonstrate how orb-web spiders change the architecture of their webs in response to prey, surroundings and wind loading. The overall shape of the web and a range of other web parameters are determined by frame and anchor threads. In the wild, unlike the lab, the anchor threads are attached to branches and leaves that are not stationary but move, which affects the thread tension field. Here we experimentally test the effect of a moving support structure on the construction behaviour and web-parameters of the garden cross spider Araneus diadematus. We found no significant differences in building behaviour between rigid and moving anchors in total time spent and total distance covered nor in the percentage of the total time spent and distance covered to build the three major web components: radials, auxiliary and capture spirals. Moreover, measured key parameters of web-geometry were equally unaffected. These results call for re-evaluation of common understanding of spider webs as thread tensions are often considered to be a major factor guiding the spider during construction and web-operation.

Sign in / Sign up

Export Citation Format

Share Document