Spiders are a hyperdiverse taxon and among the most abundant predators in nearly all terrestrial habitats. Their success is often attributed to key developments in their evolution such as silk and venom production and major apomorphies such as a whole-genome duplication. Resolving deep relationships within the spider tree of life has been historically challenging, making it difficult to measure the relative importance of these novelties for spider evolution. Whole-genome data offer an essential resource in these efforts, but also for functional genomic studies. Here, we present de novo assemblies for three spider species: Ryuthela nishihirai (Liphistiidae), a representative of the ancient Mesothelae, the suborder that is sister to all other extant spiders; Uloborus plumipes (Uloboridae), a cribellate orbweaver whose phylogenetic placement is especially challenging; and Cheiracanthium punctorium (Cheiracanthiidae), which represents only the second family to be sequenced in the hyperdiverse Dionycha clade. These genomes fill critical gaps in the spider tree of life. Using these novel genomes along with 25 previously published ones, we examine the evolutionary history of spidroin gene and structural hox cluster diversity. Our assemblies provide critical genomic resources to facilitate deeper investigations into spider evolution. The near chromosome-level genome of the 'living fossil' R. nishihirai represents an especially important step forward, offering new insights into the origins of spider traits.

• Keywords
• Hi‐C, Mesothelae, assembly, chromosome, karyotype, spider silk,
• MeSH
• Phylogeny * MeSH
• Genome genetics   MeSH
• Silk genetics   MeSH
• Animals, Poisonous MeSH
• Spiders * genetics   classification   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Silk MeSH

Spider webs that serve as snares are one of the most fascinating and abundant type of animal architectures. In many cases they include an adhesive coating of silk lines-so-called viscid silk-for prey capture. The evolutionary switch from silk secretions forming solid fibres to soft aqueous adhesives remains an open question in the understanding of spider silk evolution. Here we functionally and chemically characterized the secretions of two types of silk glands and their behavioural use in the cellar spider, Pholcus phalangioides. Both being derived from the same ancestral gland type that produces fibres with a solidifying glue coat, the two types produce respectively a quickly solidifying glue applied in thread anchorages and prey wraps, or a permanently tacky glue deployed in snares. We found that the latter is characterized by a high concentration of organic salts and reduced spidroin content, showing up a possible pathway for the evolution of viscid properties by hygroscopic-salt-mediated hydration of solidifying adhesives. Understanding the underlying molecular basis for such radical switches in material properties not only helps to better understand the evolutionary origins and versatility of ecologically impactful spider web architectures, but also informs the bioengineering of spider silk-based products with tailored properties.

• Keywords
• adhesive, convergence, piriform silk, spider silk, spidroin, viscid silk,
• MeSH
• Adhesives chemistry   MeSH
• Biological Evolution MeSH
• Silk * chemistry   MeSH
• Spiders * chemistry   MeSH
• Predatory Behavior MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Adhesives MeSH
• Silk * MeSH

Short staple microfibers (SSM) based on chitosan (CS) or silk fibroin (SF) were fabricated via the wet-rotate-spinning technique and employed to adsorb hexavalent chromium from aqueous solution. Adsorption efficiencies, physicochemical and morphological properties of CS and SF-SSM were systematically investigated and evaluated before and after adsorption of Cr(VI) using different techniques like ATR-FTIR, TGA, XRD, XPS, and SEM. CS and SF-SSM showed removal efficiency (>90 %) toward Cr(VI) ions. Pseudo-second order kinetic and Langmuir isotherm models could describe the Cr(VI) ions uptake process. Considering the inexpensive, sustainability and higher adsorption capacity of CS and SF-SSM hold great promising applications as natural adsorbent materials for removing different hazardous metals from aqueous medium.

• Keywords
• Adsorption, Chitosan, Chromium (VI), Short-staple fibers, Silk fibroin, Thermodynamic studies,
• MeSH
• Chitosan chemistry   MeSH
• Chromium chemistry   isolation & purification   MeSH
• Fibroins chemistry   MeSH
• Kinetics MeSH
• Carbohydrate Conformation MeSH
• Surface Properties MeSH
• Thermodynamics * MeSH
• Particle Size MeSH
• Publication type
• Journal Article MeSH
• Comparative Study MeSH
• Names of Substances
• Chitosan MeSH
• Chromium MeSH
• Fibroins MeSH

Larvae of many lepidopteran species produce a mixture of secretory proteins, known as silk, for building protective shelters and cocoons. Silk consists of a water-insoluble silk filament core produced in the posterior silk gland (PSG) and a sticky hydrophilic coating produced by the middle silk gland (MSG). In Bombyx mori, the fiber core comprises three proteins: heavy chain fibroin (Fib-H), light chain fibroin (Fib-L) and fibrohexamerin (Fhx, previously referred to as P25). To learn more about the role of Fhx, we used transcription activator-like effector nuclease (TALEN) mutagenesis and prepared a homozygous line with a null mutation in the Fhx gene. Our characterization of cocoon morphology and silk quality showed that the mutation had very little effect. However, a detailed inspection of the secretory cells in the posterior silk gland (PSG) of mid-last-instar mutant larvae revealed temporary changes in the morphology of the endoplasmic reticulum. We also observed a morphological difference in fibroin secretory globules stored in the PSG lumen of Fhx mutants, which suggests that their fibroin complexes have a slightly lower solubility. Finally, we performed an LC-MS-based quantitative proteomic analysis comparing mutant and wild-type (wt) cocoon proteins and found a high abundance of a 16 kDa secretory protein likely involved in fibroin solubility. Overall, our study shows that whilst Fhx is dispensable for silk formation, it contributes to the stability of fibroin complexes during intracellular transport and affects the morphology of fibroin secretory globules in the PSG lumen.

• Keywords
• BMSK0001030, BMSK0001060, ER stress, ER whorls, Gene editing, Targeted mutagenesis,
• MeSH
• Bombyx * genetics   ultrastructure   MeSH
• Endoplasmic Reticulum metabolism   ultrastructure   MeSH
• Fibroins genetics   metabolism   ultrastructure   MeSH
• Silk * chemistry   genetics   MeSH
• Mutation MeSH
• Mutagenesis, Site-Directed methods   MeSH
• Salivary Glands * cytology   ultrastructure   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• fhx protein, Bombyx mori MeSH Browser
• Fibroins MeSH
• Silk * MeSH

Filippi's glands (FGs), formerly also called Lyonet's glands, are accessory secretory structures of the labial (silk) glands of lepidopteran caterpillars, which were implicated to play an important role in the maturation of the silk material and the construction of the cocoon. In our previous study, we have identified several species of giant silk moths that completely lack the FGs. Interestingly, the absence of FGs in these species correlates with the construction of a loose cocoon architecture. We investigated the functions of FGs by their surgical extirpation in the last instar larvae of the silkworm, Bombyx mori. We found that the absence of FGs altered the structure of the resulting cocoon, in which the different layers of silk were separated. In further experiments, we found no effects of the absence of FGs on larval cocoon formation behavior or on changes in cocoon mass or lipid content. Differential proteomic analysis revealed no significant contribution of structural proteins from FGs to silk cocoon material, but we identified several low abundance proteins that may play a role in posttranslational modifications of some silk proteins. Proteomic analysis also revealed a difference in phosphorylation of the N-terminal sequence of fibroin-heavy chain molecule. Thus, FGs appear to affect silk stickiness during spinning by regulating posttranslational modifications. This could also explain the link that exists between the absence of these glands and the formation of loose cocoons in some giant silk moth species.

• Keywords
• Bombyx mori, Filippi’s glands, Saturniidae, cocoon structure, proteomic analysis, silk,
• MeSH
• Bombyx metabolism   MeSH
• Fibroins metabolism   MeSH
• Silk metabolism   MeSH
• Larva metabolism   MeSH
• Moths metabolism   MeSH
• Proteomics methods   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Fibroins MeSH
• Silk MeSH

• MeSH
• Edema etiology   MeSH
• Fibroins MeSH
• Hematoma MeSH
• Immobilization MeSH
• Middle Aged MeSH
• Humans MeSH
• Hand Injuries complications   MeSH
• Tendons * MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Fibroins MeSH

Tissue engineering benefits from novel materials with precisely tunable physical, chemical and mechanical properties over a broad range. Here we report a practical approach to prepare Bombyx mori silk fibroin hydrogels using the principle of non-solvent induced phase separation (NIPS). A combination of reconstituted silk fibroin (RSF) and methanol (non-solvent), with a final concentration of 2.5% w/v and 12.5% v/v respectively, maintained at 22 °C temperature turned into a hydrogel within 10 hours. Freeze-drying of this gel gave a foam with a porosity of 88%, a water uptake capacity of 89% and a swelling index of 8.6. The gelation kinetics and the loss tangent of the gels were investigated by rheometry. The changes in the morphology of the porous foams were visualized by SEM. The changes in RSF chemical composition and the relative fraction of its secondary structural elements were analyzed by ATR-FTIR along with Fourier self-deconvolution. And, the changes in the glass transition temperature, specific heat capacity and the relative fraction of crystallinity of RSF were determined by TM-DSC. Data suggested that RSF-water-methanol behaved as a polymer-solvent-non-solvent ternary phase system, wherein the demixing of the water-methanol phases altered the thermodynamic equilibrium of RSF-water phases and resulted in the desolvation and eventual separation of the RSF phase. Systematic analysis revealed that both gelation time and the properties of hydrogels and porous foams could be controlled by the ratios of RSF and non-solvent concentration as well as by the type of non-solvent and incubation temperature. Due to the unique properties we envisage that the herein prepared NIPS induced RSF hydrogels and porous foams can possibly be used for the encapsulation of cells and/or for the controlled release of both hydrophilic and hydrophobic drugs.

• MeSH
• Biocompatible Materials chemistry   MeSH
• Bombyx chemistry   MeSH
• Fibroins chemistry   MeSH
• Hydrophobic and Hydrophilic Interactions MeSH
• Hydrogels chemistry   MeSH
• Porosity MeSH
• Solvents chemistry   MeSH
• Temperature MeSH
• Tissue Engineering MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Biocompatible Materials MeSH
• Fibroins MeSH
• Hydrogels MeSH
• Solvents MeSH

Caddisfly larvae produce silk containing heavy and light fibroins, similar to the silk of Lepidoptera, for the construction of underwater structures. We analyzed the silk of Limnephilus lunatus belonging to the case-forming suborder Integripalpia. We analyzed the transcriptome, mapped the transcripts to a reference genome and identified over 80 proteins using proteomic methods, and checked the specificity of their expression. For comparison, we also analyzed the transcriptome and silk proteome of Limnephilus flavicornis. Our results show that fibroins and adhesives are produced together in the middle and posterior parts of the silk glands, while the anterior part produces enzymes and an unknown protein AT24. The number of silk proteins of L. lunatus far exceeds that of the web-spinning Plectrocnemia conspersa, a previously described species from the suborder Annulipalpia. Our results support the idea of increasing the structural complexity of silk in rigid case builders compared to trap web builders.

• Keywords
• Limnephilus flavicornis, Plectrocnemia conspersa, Fibroin, Gene duplication, Hydrophobicity, Sericin,
• MeSH
• Fibroins genetics   metabolism   chemistry   MeSH
• Silk * metabolism   chemistry   MeSH
• Insecta metabolism   genetics   MeSH
• Insect Proteins genetics   metabolism   MeSH
• Proteome MeSH
• Proteomics methods   MeSH
• Gene Expression Profiling MeSH
• Transcriptome MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH

Many lepidopteran larvae produce silk secretions to build feeding tubes and cocoons that play important protective roles in their lives. Recent research on the silk of bombycoid and pyralid moths has shown that it contains several highly abundant silk components with remarkable mechanical properties. It was also found to contain a number of other proteins of which the functions have yet to be identified. To gain an overview of the silk composition in more primitive lepidopteran species and to identify the core silk components common to most species, we analyzed the cocoon proteins of Tineola bisselliella, which belongs to the basal ditrysian moth line. Using de novo transcriptome sequencing combined with mass spectrometry (MS)-based proteomics, we detected more than 100 secretory proteins in the silk cocoons. Fibroin, sericins, and protease inhibitors were found to be the most abundant proteins, along with several novel candidate silk components. We also verified the tissue and developmental stage specificity of the silk protein expression and characterized the morphology of both the silk glands and silk in T. bisselliella. Our study provides a detailed analysis of silk in the primitive moth, expands the known set of silk-specific genes in Lepidoptera, and helps to elucidate their evolutionary relationships.

• Keywords
• Adhesive, Fibroin, Peptide fingerprinting, Sericin, Serine protease, Transcriptome, Zonadhesin-like,
• MeSH
• Biological Evolution * MeSH
• Fibroins metabolism   MeSH
• Silk * chemistry   genetics   metabolism   MeSH
• Insect Proteins genetics   metabolism   MeSH
• Protease Inhibitors metabolism   MeSH
• Larva genetics   metabolism   physiology   MeSH
• Moths * genetics   metabolism   physiology   MeSH
• Proteomics methods   MeSH
• Sericins metabolism   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Fibroins MeSH
• Silk * MeSH
• Insect Proteins MeSH
• Protease Inhibitors MeSH
• Sericins MeSH

Concomitant intake of alcoholic beverages with sustained-release oral formulations may potentially lead to dose dumping. Alcohol-resistance testing is currently a requirement for the manufacturers by regulatory authorities. Silk fibroin produced by silkworm Bombyx mori is suggested in this work as a potential alternative to a narrow spectrum of alcohol-resistant excipients. Oxycodone HCl, tramadol HCl, and flurbiprofen were selected as model drugs and formulated with regenerated silk fibroin either in the form of an amorphous solid dispersion or as a physical mixture and compressed into tablets. Preliminary compactability and tampering-resistance studies were performed. The ethanol-resistance was tested in media containing 5%, 10%, 20%, or 40% (v/v) ethanol concentration. Drug release profiles were compared using f2 similarity factor. Good mechanical tampering-resistance (tensile strength of 14.6 MPa at 400 MPa compression pressure) was obtained for tablets compressed from physical mixture. Tablets compressed from amorphous solid dispersion had lower tensile strength (2.2 MPa) but showed chemical tampering-resistance to extraction by pure ethanol (7.1% of oxycodone HCl after 24 h). Drug release is controlled predominantly by swelling and diffusion. With an increasing ethanol concentration in release medium, the tablets swelled less, resulting in a slower release. This trend was similar for all tested drugs and for both physical states formulations. No dose dumping occurred in the presence of ethanol; therefore, silk fibroin could be considered as an alternative alcohol-resistant excipient for sustained release application.

• Keywords
• alcohol-induced dose dumping, ethanol-resistant, opioids, silk fibroin, sustained-release,
• MeSH
• Fibroins chemistry   MeSH
• Delayed-Action Preparations * MeSH
• Excipients * MeSH
• Tablets MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Fibroins MeSH
• Delayed-Action Preparations * MeSH
• Excipients * MeSH
• Tablets MeSH