Search Results (10)

Spiders and other arthropods can sometimes consume others of their kind, and this is most often associated with mating activity, whereby females cannibalize males during or after mating, or during mating attempts. Nonsexual cannibalism is less common but may be associated with food availability or territorial aggression. In the Southeastern United States, a non-native orb-weaving spider, Trichonephila clavata (the “jorō spider”), is expanding its range. Prior lab experiments indicated this species to be “shy” compared to other native spiders, based on behavioral reactions to stimuli. Here, we report descriptive observations and photo-documentation of nonsexual cannibalism by this species, including from anecdotal observations, plus findings from controlled pairings of spiders, both in the lab and in natural webs in the field. In the cases where cannibalism was witnessed, it involved one female biting and killing another, typically after a short fight. When two females of a similar size were placed together in a container (n = 25 trials), fights ensued 40% of the time. When females of different sizes were paired (n = 27 trials), fights happened 18% of the time, and the larger females were not always the aggressor. Across all the lab trials (n = 52), six bouts (9%) led to the direct killing of one female. In field trials where two females were placed on an empty web (n = 14 trials), we observed one fight (7%) where the aggressor ended up killing and wrapping the other spider in silk. Given that some of these instances happened away from any web, these observations imply that the aggression is not necessarily an act of territoriality. The intraspecific aggression could arise when females are provoked or stressed, which deserves more study. Full article

Almost 70 years after the surprise discovery of a cache of textile-wrapped relics inside an early 13th-century reliquary bust, the St Eustace head reliquary (accession number 1850,1127.1), four of the textile relic wrappings were analysed by combining multiband imaging and fibre-optic reflectance spectroscopy (FORS), as well as dye analysis by high-pressure liquid chromatography coupled to mass spectrometry (HPLC-MS) and fibre analysis by scanning electron microscopy—energy dispersive X-ray spectroscopy (SEM-EDX). In all cases, the use of silk was confirmed, in line with the idea that these precious textiles were purposefully chosen for reuse in a sacred setting. Additionally, dye analysis was able to point to the possible geographic origins of the textile fragments. For 1850,1127.1.a, a mixture of sappanwood (Biancaea sappan) and flavonoid yellow dyes was commensurate with a Chinese or Central Asian origin. Mediterranean origins were thought likely for 1850,1127.1.c and 1850,1127.1.f, from the mixture of kermes (Kermes vermilio) and cochineal (likely Porphyrophora sp.), found in the mauve band of the former, and the combination of weld (Reseda luteola), madder (Rubia tinctorum) and an indigoid dye found in the latter. Finally, the unusual combination of sappanwood, orchil and a yellow dye containing flavonoid glucuronides suggested a less straightforward origin for textile 1850,1127.1.g. The other textile fragments from the reliquary were only investigated using FORS without removing them from their Perspex glass mounts. Nonetheless, indications for the presence of insect-red anthraquinone dyes, safflower (Carthamus tinctorius) and an indigoid dye were obtained from some of these fragments. The study provides a window into the landscape of availability, use and re-use in sacred contexts of precious textiles in the 13th century and evidences the geographic reach of these silks, allowing a new perspective on the St Eustace head reliquary. Full article

Sexual signalling is influenced by environmental conditions, but limited focus has been given to the influence of light conditions on mating strategies in spiders. The males of Pisaura mirabilis (Clerck, 1757) produce nuptial gifts by wrapping the dead prey with silk, and female mate choice relies on complex signals involving visual, behavioural, vibratory, and chemical cues. Considering the former, we first examined the natural illumination conditions experienced by Pisaura mirabilis in their natural habitat. Specifically, we compared the light levels of spiders situated on leaves to those found within the denser vegetation where they typically reside. In the laboratory, we manipulated the visual conditions during courtship and mating using white (high visibility) and red (low visibility) light, and we blocked male spinnerets with dental silicone to assess the impact of males’ ability to produce silk on mating success. The aim of the study was to examine the effect of visual conditions on male investment in nuptial feeding. The places where spiders spend time outside of vegetation in the wild were 40 times brighter than habitats inside vegetation. The mating success was not significantly dependent on light conditions, but males under red lights invested more effort in the production of nuptial gifts than males under white lights. Males with blocked spinnerets had a lower mating success than silk-intact males. The blocked males under red light, although unable to produce silk, also invested more time in attempts to wrap the gift with silk compared to the silk-intact males or silk-blocked males under white lights. These results suggest that gift production is influenced by an interplay between female behaviour and light conditions, highlighting the significance of taking into account visual conditions in spider mating behaviour research. Full article

We investigated the role of a sirolimus-embedded silk microneedle (MN) wrap as an external vascular device for drug delivery efficacy, inhibition of neointimal hyperplasia, and vascular remodeling. Using dogs, a vein graft model was developed to interpose the carotid or femoral artery with the jugular or femoral vein. The control group contained four dogs with only interposed grafts; the intervention group contained four dogs with vein grafts in which sirolimus-embedded silk-MN wraps were applied. After 12-weeks post-implantation, 15 vein grafts in each group were explanted and analyzed. Vein grafts applied with the rhodamine B–embedded silk-MN wrap showed far higher fluorescent signals than those without the wrap. The diameter of vein grafts in the intervention group decreased or remained stable without dilatation; however, it increased in the control group. The intervention group had femoral vein grafts with a significantly lower mean neointima-to-media ratio, and had vein grafts with an intima layer showing a significantly lower collagen density ratio than the control group. In conclusion, sirolimus-embedded silk-MN wrap in a vein graft model successfully delivered the drug to the intimal layer of the vein grafts. It prevented vein graft dilatation, avoiding shear stress and decreasing wall tension, and it inhibited neointimal hyperplasia. Full article

Li[Ni_0.8Co_0.15Al_0.05]O₂ (NCA) is a cathode material for lithium-ion batteries and has high power density and capacity. However, this material has disadvantages such as structural instability and short lifespan. To address these issues, herein, we explore the impact of N-doped carbon wrapping on NCA. Sericin, an easily obtained carbon- and nitrogen-rich component of silk cocoons, is utilized as the precursor material. The electrochemical performance evaluation of N-doped carbon-coated NCA shows that the capacity retention of 0.3 NC@NCA at 1C current density is 69.83% after 200 cycles, which is about 19% higher than the 50.65% capacity retention of bare NCA. The results reveal that the sericin-resultant N-doped carbon surface wrapping improves the cycling stability of NC@NCA. Full article

Textile metal threads were used to decorate historical Croatian textiles. There are three basic types of metal threads usually used on historical textiles in Croatia. These are narrow stripes, wires, and combined metal textile yarn called “srma”, made of metal thread spirally wrapped around the nonmetal textile yarn. Textile yarns were made of silk, linen, wool, or cotton. Metal threads were primarily made of gold, silver, and copper, and different alloys of these metals or threads are layered in the structure. Analysis of metal threads with three different methods was made and the most adequate method for the analysis of metal threads from historical textiles was established. Metal thread analysis was performed with scanning electron microscopy with an energy-dispersive X-ray detector (SEM-EDX), which was determined to be the most suitable for the analysis of historical textiles if cross-section analysis of metal threads is also performed. Textile threads from combined metal textile threads were analysed with a light microscope. This information of the metal threads’ content and structure as well as the composition of textile thread can lead to an understanding of the technology of production threads and also temporal and spatial dating of textile objects which is helpful to conservators and restorers of valuable historical textiles. Full article

Aerogel fiber, with the characteristics of ultra-low density, ultra-high porosity, and high specific surface area, is the most potential candidate for manufacturing wearable thermal insulation material. However, aerogel fibers generally show weak mechanical properties and complex preparation processes. Herein, through firstly preparing a cellulose acetate/polyacrylic acid (CA/PAA) hollow fiber using coaxial wet-spinning followed by injecting the silk fibroin (SF) solution into the hollow fiber, the CA/PAA-wrapped SF aerogel fibers toward textile thermal insulation were successfully constructed after freeze-drying. The sheath (CA/PAA hollow fiber) possesses a multiscale porous structure, including micropores (11.37 ± 4.01 μm), sub-micron pores (217.47 ± 46.16 nm), as well as nanopores on the inner (44.00 ± 21.65 nm) and outer (36.43 ± 17.55 nm) surfaces, which is crucial to the formation of a SF aerogel core. Furthermore, the porous CA/PAA-wrapped SF aerogel fibers have many advantages, such as low density (0.21 g/cm³), high porosity (86%), high strength at break (2.6 ± 0.4 MPa), as well as potential continuous and large-scale production. The delicate structure of multiscale porous sheath and ultra-low-density SF aerogel core synergistically inhibit air circulation and limit convective heat transfer. Meanwhile, the high porosity of aerogel fibers weakens heat transfer and the SF aerogel cellular walls prevent infrared radiation. The results show that the mat composed of these aerogel fibers exhibits excellent thermal insulating properties with a wide working temperature from −20 to 100 °C. Therefore, this SF-based aerogel fiber can be considered as a practical option for high performance thermal insulation. Full article

The aim of this paper is to present the results of research undertaken on a wooden box that holds an important historical book: a hand Bible handwritten in the thirteenth century. Tradition connects this Bible to the name of Marco Polo (Venice, 1254–1324), who was supposedly the owner—the book possibly accompanied him on his travels (1262 and 1271) to China. The Bible is of fine workmanship and written on thin parchment, and its container—along with a yellow silk cloth—are preserved in the ancient and prestigious Laurentian Library in Florence. The manuscript was in very poor condition and was being restored during the period of study (2011). Surveys were carried out to determine the place and period of manufacture of the box, and to determine if it was contemporary to or later than the manuscript it contained or whether it was made in China or Europe. An additional aim of the work was to demonstrate that a fast and inexpensive in situ survey under imperfect time and space conditions was possible using in-depth observation and simple tools as well as a portable microscope, all performed without sampling. During the restoration process, a team of experts used instruments helpful in determining the chemical composition of the paper and related ink. Other specialists studied the paleography of the text. The results indicate that the Bible is definitely from the same period as Marco Polo. Nothing excludes the possibility that Marco Polo may have seen it or lived not too far from this manuscript, which traveled in a small wooden box, wrapped in a precious yellow silk cloth. Full article

The outstanding material properties of spider dragline silk fibers have been attributed to two spidroins, major ampullate spidroins 1 and 2 (MaSp1 and MaSp2). Although dragline silk fibers have been treated with different chemical solvents to elucidate the relationship between protein structure and fiber mechanics, there has not been a comprehensive proteomic analysis of the major ampullate (MA) gland, its spinning dope, and dragline silk using a wide range of chaotropic agents, inorganic salts, and fluorinated alcohols to elucidate their complete molecular constituents. In these studies, we perform in-solution tryptic digestions of solubilized MA glands, spinning dope and dragline silk fibers using five different solvents, followed by nano liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis with an Orbitrap Fusion™ Tribrid™. To improve protein identification, we employed three different tryptic peptide fragmentation modes, which included collision-induced dissociation (CID), electron transfer dissociation (ETD), and high energy collision dissociation (HCD) to discover proteins involved in the silk assembly pathway and silk fiber. In addition to MaSp1 and MaSp2, we confirmed the presence of a third spidroin, aciniform spidroin 1 (AcSp1), widely recognized as the major constituent of wrapping silk, as a product of dragline silk. Our findings also reveal that MA glands, spinning dope, and dragline silk contain at least seven common proteins: three members of the Cysteine-Rich Protein Family (CRP1, CRP2 and CRP4), cysteine-rich secretory protein 3 (CRISP3), fasciclin and two uncharacterized proteins. In summary, this study provides a proteomic blueprint to construct synthetic silk fibers that most closely mimic natural fibers. Full article

Spider aciniform (wrapping) silk is a remarkable fibrillar biomaterial with outstanding mechanical properties. It is a modular protein consisting, in Argiope trifasciata, of a core repetitive domain of 200 amino acid units (W units). In solution, the W units comprise a globular folded core, with five α-helices, and disordered tails that are linked to form a ~63-residue intrinsically disordered linker in concatemers. Herein, we present nuclear magnetic resonance (NMR) spectroscopy-based ¹⁵N spin relaxation analysis, allowing characterization of backbone dynamics as a function of residue on the ps–ns timescale in the context of the single W unit (W₁) and the two unit concatemer (W₂). Unambiguous mapping of backbone dynamics throughout W₂ was made possible by segmental NMR active isotope-enrichment through split intein-mediated trans-splicing. Spectral density mapping for W₁ and W₂ reveals a striking disparity in dynamics between the folded core and the disordered linker and tail regions. These data are also consistent with rotational diffusion behaviour where each globular domain tumbles almost independently of its neighbour. At a localized level, helix 5 exhibits elevated high frequency dynamics relative to the proximal helix 4, supporting a model of fibrillogenesis where this helix unfolds as part of the transition to a mixed α-helix/β-sheet fibre. Full article