Electrospinning Recombinant Spider Silk Fibroin-Reinforced PLGA Membranes: A Biocompatible Scaffold for Wound Healing Applications.

Polylactide-polyglycolide (PLGA) is one of the most attractive polymeric biomaterials used to fabricate medical devices for drug delivery and tissue engineering applications. Nevertheless, the utilization of PLGA in load-bearing applications is restricted due to its inadequate mechanical properties. This study examines the potential of recombinant silk fibroin (eADF4), a readily producible biomaterial, as a reinforcing agent for PLGA. The PLGA/eADF4 composite membranes were developed by using the process of electrospinning. The spinnability of the electrospinning solutions and the physicochemical, mechanical, and thermal properties of the composite membranes were characterized. The addition of eADF4 increased the viscosity of the electrospinning solutions and enhanced both the mechanical characteristics and the thermal stability of the composites. This study demonstrates that PLGA membranes reinforced with recombinant spider silk fibroin are noncytotoxic, significantly enhance cell migration and wound closure, and do not trigger an inflammatory response, making them ideal candidates for advanced wound healing applications.

Description of two new species of the genus Trachelas L. Koch, 1872 and the male of T.gaoligongensis Jin, Yin & Zhang, 2017 from China (Araneae, Trachelidae).

Two new spider species of the genus Trachelas L. Koch, 1872 are described from China: Trachelaskavanaughi sp. nov. (♀) and Trachelasventriosus sp. nov. (♀). The male of Trachelasgaoligongensis Jin, Yin & Zhang, 2017 is described for the first time. Illustrations of the body and copulatory organs and a distribution map are provided.

A Curious Case of Medium-Vessel Vasculitis.

Vasculitis, or the inflammation of vessels due to primary or secondary causes, may arise from numerous etiologies, often leading to diagnostic uncertainty. Delayed treatment due to diagnostic or etiologic uncertainty presents a significant clinical risk, with consequences including organ failure and mortality. We describe a case of a 58-year-old male with a history including ankylosing spondylitis who presented with painful ulcers involving the bilateral lower extremities following a trip to the southern Texas border. Histopathology revealed medium-vessel vasculitis; however, the search for a likely etiology in the setting of a unique combination of potential vasculitis precipitants, including glochid inoculation, a spider bite, prior IL-17 inhibitor use, and inflammatory bowel disease, contributed to treatment delay and disease progression. Although the patient was ultimately successfully treated with systemic corticosteroids, this case highlights the importance of initiating prompt therapy once vasculitis is recognized to prevent disease progression, even if lacking an identified etiology.

Enhanced detection of diabetes mellitus using novel ensemble feature engineering approach and machine learning model.

Diabetes is a persistent health condition led by insufficient use or inappropriate use of insulin in the body. If left undetected, it can lead to further complications involving organ damage such as heart, lungs, and eyes. Timely detection of diabetes helps obtain the right medication, diet, and exercise plan to lead a healthy life. ML approach has been utilized to obtain rapid and reliable diabetes detection, however, existing approaches suffer from the use of limited datasets, lack of generalizability, and lower accuracy. This study proposes a novel feature extraction approach to overcome these limitations by using an ensemble of convolutional neural network (CNN) and long short-term memory (LSTM) models. Multiple datasets are combined to make a larger dataset for experiments and multiple features are utilized for investigating the efficacy of the proposed approach. Features from the extra tree classifier, CNN, and LSTM are also considered for comparison. Experimental results reveal the superb performance of CNN-LSTM-based features with random forest model obtaining a 0.99 accuracy score. This performance is further validated by comparison with existing approaches and k-fold cross-validation which shows the proposed approach provides robust results.

Diagnosing skin cancer using social spider optimization (SSO) and error correcting output codes (ECOC) with weighted hamming distance.

Skin cancer is a common disease resulting from genetic defects, and early detection is critical to improve treatment outcomes. Diagnostic programs that use computer aid especially those that use supervised learning are very useful in early diagnosis of skin cancer. This research therefore presents a new approach that integrates optimization methods with supervised learning to improve skin cancer diagnosis using machine vision approach. The presented method is initiated by data pre-processing that involves the removal of unnecessary data. Then, to segment the images, a combination of K-means clustering and social spider optimization technique is employed. The region of interest is then extracted from the segmented image and from this region a convolutional neural network extracts the significant features. To enhance the classification performance as compared with the standard classifiers, this research introduces a new concept of error correcting output codes coupled with a weighted Hamming distance in the group of gamma classifiers. The ability of the proposed approach in segmentation of skin lesions and classifying them was tested using samples from the ISIC-2017 and ISIC-2016 databases. The introduced method obtained state-of-the-art accuracy on both datasets (ISIC-2016: 97.10%, ISIC-2017: 95.17%). In particularly, the accuracy of the introduced approach for both these databases is at least 1.17% higher than the compared methods. This proves the high performance of the suggested method based on the usage of the convolutional neural networks for feature extraction and gamma classifiers with error correcting output codes for classification in skin cancer detection.

Detection of Filariid Infections in Mexican Primate Populations Through qPCR.

Filariae are parasitic nematodes of high veterinary and medical importance, responsible for some acute tropical diseases. They are transmitted through the bite of hematophagous vectors such as biting midges and blackflies. Filariae are among the most prevalent vector-borne parasitoses in Neotropical primates in which severe infections can cause inflammatory reactions and tissue damage. Given the location inside the host (peritoneal cavity, bloodstream, and lymphatics), the detection of filariid nematodes is challenging and is mostly postmortem; hence the scarcity of studies on the prevalence of filariae in wild primate populations. Here, we report the prevalence of filariid infections in free-ranging populations of Geoffroy's spider (Ateles geoffroyi) and black howler (Alouatta pigra) monkeys across southern Mexico, using a combination of noninvasive sampling and molecular diagnostic techniques. Fecal samples were screened for filariid DNA by qPCR protocols. A total of 88 samples were examined with an overall prevalence of 26%. Filariae were slightly more common in spider monkeys compared to howler monkeys. This study constitutes the first report of the prevalence of infection of filariid nematodes in populations of wild spider monkey across southern Mexico, and the first reporting of filariae in black howler monkeys, as part of a new era of primate parasitology and the diagnostics of parasite infections in light of the everyday more affordable molecular tools.

Three Novel Spider Genomes Unveil Spidroin Diversification and Hox Cluster Architecture: Ryuthela nishihirai (Liphistiidae), Uloborus plumipes (Uloboridae) and Cheiracanthium punctorium (Cheiracanthiidae).

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.

Phylogenetics and species delimitation of the recluse spider, Loxosceles rufescens (Araneae: Sicariidae) populations invading Bangkok, Thailand.

The Mediterranean recluse spider, Loxosceles rufescens, has been discovered for the first time inhabiting human dwellings in Bangkok, Thailand. Expeditions across 39 localities revealed five establishments with L. rufescens populations. The highest density was recorded in a storage house on Yaowarat Road, located in the heart of Bangkok's Chinatown, where 315 individuals were found, including adults, juveniles, and spiderlings. This medically significant spider's presence in such a densely populated urban area raises concerns about potential envenomation risks. Thirteen specimens of L. rufescens were extracted for DNA and sequenced for molecular phylogenetic analyses. COI and ITS2 markers were used to investigate relationships within L. rufescens and across available Loxosceles species sequences. Results indicate COI is superior for resolving species-level genetic clusters compared to ITS2. Surprisingly, L. rufescens individuals from the same house were found in significantly distant COI lineages, suggesting mtDNA may not be suitable for studying intra-specific phylogeography in this case. Species delimitation methods ABGD and ASAP demonstrated promising results for both COI and ITS2, while bPTP and GMYC tended to overestimate species numbers. ITS2 exhibited high sequence similarity in L. rufescens, suggesting potential utility as a barcoding marker for identification of this globally distributed species. Genetic distance analyses revealed a potential barcoding gap (K2P) of 8-9 % for COI and <2 % for ITS2 in Loxosceles. This study contributes valuable sequence data for the medically important genus Loxosceles and highlights the need for integrative approaches in understanding its evolution and spread. The findings have important implications for pest management strategies and public health in urban environments.

Discovery of Gibellula floridensis from Infected Spiders and Analysis of the Surrounding Fungal Entomopathogen Community.

Characterization of fungal spider pathogens lags far behind their insect counterparts. In addition, little to nothing is known concerning the ecological reservoir and/or fungal entomopathogen community surrounding infection sites. Five infected spider cadavers were identified in the neo-tropical climate of north-central Florida, USA, from three of which viable cultures were obtained. Multi-locus molecular phylogenetic and morphological characterization identified one isolate as a new Gibellula species, here named, Gibellula floridensis, and the other isolates highly similar to Parengyodontium album. The fungal entomopathogen community surrounding infected spiders was sampled at different habitats/trophic levels, including soil, leaf litter, leaf, and twig, and analyzed using ITS amplicon sequencing. These data revealed broad but differential distribution of insect-pathogenic fungi between habitats and variation between sites, with members of genera belonging to Metarhizium and Metacordyceps from Clavicipitaceae, Purpureocillium and Polycephalomyces from Ophiocordyceps, and Akanthomyces and Simplicillium from Cordycipitaceae predominating. However, no sequences corresponding to Gibellula or Parengyodontium, even at the genera levels, could be detected. Potential explanations for these findings are discussed. These data highlight novel discovery of fungal spider pathogens and open the broader question regarding the environmental distribution and ecological niches of such host-specific pathogens.

Characterization of the Virome Associated with the Ubiquitous Two-Spotted Spider Mite, Tetranychus urticae.

Agricultural pests can cause direct damage to crops, including chlorosis, loss of vigor, defoliation, and wilting. In addition, they can also indirectly damage plants, such as by transmitting pathogenic micro-organisms while feeding on plant tissues, affecting the productivity and quality of crops and interfering with agricultural production. Among the known arthropod pests, mites are highly prevalent in global agriculture, particularly those from the Tetranychidae family. The two-spotted spider mite, Tetranychus urticae, is especially notorious, infesting about 1600 plant species and causing significant agricultural losses. Despite its impact on agriculture, the virome of T. urticae is poorly characterized in the literature. This lack of knowledge is concerning, as these mites could potentially transmit plant-infecting viral pathogens, compromising food security and complicating integrated pest management efforts. Our study aimed to characterize the virome of the mite T. urticae by taking advantage of publicly available RNA deep sequencing libraries. A total of 30 libraries were selected, covering a wide range of geographic and sampling conditions. The library selection step included selecting 1 control library from each project in the NCBI SRA database (16 in total), in addition to the 14 unique libraries from a project containing field-collected mites. The analysis was conducted using an integrated de novo virus discovery bioinformatics pipeline developed by our group. This approach revealed 20 viral sequences, including 11 related to new viruses. Through phylogenetic analysis, eight of these were classified into the Nodaviridae, Kitaviridae, Phenuiviridae, Rhabdoviridae, Birnaviridae, and Qinviridae viral families, while three were characterized only at the order level within Picornavirales and Reovirales. The remaining nine viral sequences showed high similarity at the nucleotide level with known viral species, likely representing new strains of previously characterized viruses. Notably, these include the known Bean common mosaic virus (BCMV) and Phaseolus vulgaris alphaendornavirus 1, both of which have significant impacts on bean agriculture. Altogether, our results expand the virome associated with the ubiquitous mite pest T. urticae and highlight its potential role as a transmitter of important plant pathogens. Our data emphasize the importance of continuous virus surveillance for help in the preparedness of future emerging threats.

The protamines of the spider Steatoda sp. provide an example of liquid-liquid phase separation chromatin transitions during spermiogenesis.

While there is extensive information about sperm nuclear basic proteins (SNBP) in vertebrates, there is by comparison, very little information in Arthropoda. This paper aims to contribute to filling this gap by analyzing these proteins in the sperm of the noble false widow spider Steatoda nobilis (Order Araneae, Family Theridiidae). To this end, we have developed a protein extraction method that allows the extraction of both cysteine-containing and non-Cysteine-containing protamines that is suitable for the preparation and analysis of SNBPs from samples where the amount of starting tissue material is limited. We carried out top-down mass spectrometry sequencing and molecular phylogenetic analyses to characterize the protamines of S. nobilis and other spiders. We also used electron microscopy to analyse the chromatin organization of the Steatoda sperm and we found it to exhibit liquid-liquid phase spinodal decomposition during the late stages of spermiogenesis. These studies further our knowledge on the distribution of SNBPs within the animal kingdom and provide additional support for a proposed evolutionary origin of many protamines from a histone H1 (H5) replication independent precursor.

Using a conditioned place preference assay in fruit flies to examine effects of insecticidal compounds on contextual memory.

Insecticides are vital for safeguarding agricultural crops against pests, albeit many lack selectivity towards pest species and are poorly bio-degradable. This leads to targeting of beneficial organisms like pollinators and widespread environmental contamination of soil and water. Exposure to insecticides such as neonicotinoids causes insect paralysis and mortality at higher doses, while sublethal doses can disrupt other functions that are crucial for survival such as learning and memory performance. Potent and selective arachnid venom peptides affecting a variety of molecular targets are being explored as bioinsecticide candidates. However, their effect on insect learning is poorly understood. We therefore established a sucrose-induced conditioned place preference (CPP) assay using Drosophila melanogaster fruit flies to provide a means of evaluating how various classes of insecticidal compounds interact with insect memory to assess their broader ecological consequences. Our results confirmed the adverse effect of a sublethal dose of the neonicotinoid insecticide imidacloprid (20 pg/fly) on fly CPP formation upon daily injection during the conditioning phase. However, imidacloprid did not affect CPP retrieval when applied after the conditioning phase. Sublethal doses of the two insecticidal spider venom peptides µ-DGTX-Dc1a (Dc1a; 70 pg/fly) and U1-AGTX-Ta1a (Ta1a; 125 pg/fly) had no effect on either CPP formation or retrieval, underlining their potential as novel and safe bioinsecticide candidates.

The genome sequence of the harvestman spider, Odiellus spinosus (Bosc, 1792).

We present a genome assembly from an individual female Odiellus spinosus (harvestman spider; Arthropoda; Arachnida; Opiliones; Phalangiidae). The genome sequence spans 443.70 megabases. Most of the assembly is scaffolded into 16 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 16.07 kilobases in length.

The role of wild bees and cavity-nesting wasps as ecological indicators of the last traditionally managed meadows in Eastern Europe.

The number of wild bees and cavity-nesting wasps is abundant in agricultural areas and they contribute significantly to ecosystem services. Due to their specialization in nesting sites and food sources, these groups are sensitive to habitat condition changes and they are therefore important indicators for environmental impact assessments. As semi-natural habitats are steadily declining and often understudied, their significance for research is increasingly recognized. During this research, the role of wild bee species and cavity-nesting Hymenopteran taxa as indicators was examined, along the unique combination of high nature value and traditional land use habitats in Eastern Europe, Transylvania. Transects and trap nests were used to test the diversity and abundance of wild bees and cavity-nesting Hymenopterans to identify possible differences between highly protected and less protected areas. The differences in taxonomic groups between the sites and the potential effects of landscape structure on wild bees and cavity-nesting Hymenopterans were also assessed. We detected a high diversity of wild bee species and a significant species replacement from one study year to another. Among the nest-building Hymenopteran taxa, the majority of nests was built by Trypoxylon sp. during both study years, with a stronger dominance in the second year. The different taxonomic groups of wild bees and cavity-nesting Hymenopterans showed differences in their habitat affinities. The majority of the sampled bumblebee species as well as Trypoxylon sp. had an affinity towards the study sites located within the highly protected study area. Altogether, we found different habitat preferences for different Hymenopteran groups (both wild bees and wasps) and conclude that these groups definitely have the potential to serve as indicators for differences in the intensity of land use.

Thermoregulation Effects of Phoneutria nigriventer Isolated Toxins in Rats.

Body temperature is primarily regulated by the hypothalamus, ensuring proper metabolic function. Envenomation by Phoneutria nigriventer can cause symptoms such as hypothermia, hyperthermia, sweating, and shivering, all related to thermoregulation. This study aims to analyze and identify components of the venom that affect thermoregulation and to evaluate possible mechanisms. Rats were used for thermoregulation analysis, venom fractionation by gel filtration and reverse-phase chromatography (C18), and sequencing by Edman degradation. The venom exhibited hypothermic effects in rats, while its fractions demonstrated both hypothermic (pool II) and hyperthermic (pool III) effects. Further separations of the pools with C18 identified specific peaks responsible for these effects. However, as the peaks were further purified, their effects became less significant. Tests on U87 human glioblastoma cells showed no toxicity. Sequencing of the most active peaks revealed masses similar to those of the Tachykinin and Ctenotoxin families, both known to act on the nervous system. The study concludes that molecules derived from venom can act synergistically or antagonistically. Additionally, toxins that affect thermoregulation are poorly studied and require further characterization. These toxins could potentially serve as sources for the development of new thermoregulatory drugs.

Sequence analysis, homology modeling, tissue expression, and potential functions of seven putative acetylcholinesterases in the spider Cupiennius salei.

Acetylcholine esterases (AChEs) are essential enzymes in cholinergic synapses, terminating neurotransmission by hydrolysing acetylcholine. While membrane bound AChEs at synaptic clefts efficiently perform this task, soluble AChEs are less stable and effective, but function over broader areas. In vertebrates, a single gene produces alternatively spliced forms of AChE, whereas invertebrates often have multiple genes, producing both enzyme types. Despite their significance as pesticide targets, the physiological roles of invertebrate AChEs remain unclear. Here, we characterized seven putative AChEs in the wandering spider, Cupiennius salei, a model species for neurophysiological studies. Sequence analyses and homology modeling predicted CsAChE7 as the sole stable, membrane-bound enzyme functioning at synaptic clefts, while the others are likely soluble enzymes. In situ hybridization of sections from the spider's nervous system revealed CsAChE7 transcripts co-localizing with choline acetyltransferase in cells that also exhibited AChE activity. CsAChE7 transcripts were also found in rapidly adapting mechanosensory neurons, suggesting a role in precise and transient activation of postsynaptic cells, contrasting with slowly adapting, also cholinergic, neurons expressing only soluble AChEs, which allow prolonged activation of postsynaptic cells. These findings suggest that cholinergic transmission is influenced not only by postsynaptic receptors but also by the enzymatic properties regulating acetylcholine clearance. We also show that acetylcholine is a crucial neurotransmitter in the spider's visual system and sensory and motor pathways, but absent in excitatory motor neurons at neuromuscular junctions, consistent with other arthropods. Our findings on sequence structures may have implications for the development of neurological drugs and pesticides.

Influence of Initial Secondary Structure on Conformation and Mechanical Properties of Spider Silk Protein Gels.

Recombinant spider silk protein (RSP) is a promising biomaterial for developing high-performance materials independent of fossil fuels. In this study, we investigated the influence of the initial secondary structure of RSPs on the properties of RSP-based hydrogels. By altering the initial structure of RSP to ß-sheets (ß-RSP), α-helices (α-RSP), and random coils (rc-RSP) through solvent treatment, we compared the structures and mechanical properties of the resulting gels. Solid-state NMR revealed a ß-sheet-rich structure in all gels, with the α-RSP gel exhibiting significantly higher strength and Young's modulus compared to the rc-RSP gel. X-ray diffraction revealed that the α-RSP gel had a unique crystalline structure, distinguishing it from the ß-RSP and rc-RSP gels. The different initial secondary structures possibly lead to variations in the crystalline and network structures of the molecular chains within the gels, explaining the superior mechanical properties observed in the α-RSP gels.

Green extraction of chitin from hard spider crab shells.

A green protocol to extract chitin from crab shells using water soluble ionic liquids (ILs) is here reported. Compared to conventional multistep acid-base extraction methods, this one-pot procedure achieves pulping of recalcitrant crustacean waste shells by employing ammonium acetate, ammonium formate and hydroxylammonium acetate as water-soluble, low-cost and easy to prepare ILs. An extensive parametric analysis of the pulping process has been carried out with different ILs, different ratios, temperature and time. The optimized protocol provides a high-quality chitin comparable, if not better, to commercial chitin. The best results were obtained at 150 °C with ammonium formate prepared in-situ from aqueous ammonia and formic acid: chitin was isolated in a 17 wt% yield (based on dried crab shells as starting biowaste), a degree of acetylation (DA) > 94 %, a crystallinity index of 39-46 %, a molecular weight up to 6.6 × 105 g/mol and a polydispersity of ca 2.0.

Spider silk tensile performance does not correlate with web use.

Spider silk is amongst the toughest materials produced by living systems, but its tensile performance varies considerably between species. Despite the extensive sampling of the material properties and composition of dragline silk, the understanding why some silks perform better than others is still limited. Here, I adopted a phylogenetic comparative approach to re-analyse structural and mechanical data from the Silkome database and the literature across 164 species to (a) provide an extended model of silk property evolution, (b) test for correlations between structural and mechanical properties, and (c) to test if silk tensile performance differs between web-building and non-web-building species. Unlike the common notion that orb-weavers have evolved the best performing silks, outstanding tensile properties were found both in and outside the araneoid clade. Phylogenetic linear models indicated that the mechanical and structural properties of spider draglines poorly correlate, but silk strength and toughness correlated better with birefringence (an indicator of the material anisotropy) than crystallinity. Furthermore, in contrast to previous ideas, silk tensile performance did not differ between ecological guilds. These findings indicate multiple unknown pathways towards the evolution of spider silk tensile super-performance, calling for a better integration of non-orb-weaving spiders in spider silk studies.

Optimizing Nav1.7-Targeted Analgesics: Revealing Off-Target Effects of Spider Venom-Derived Peptide Toxins and Engineering Strategies for Improvement.

The inhibition of Nav1.7 is a promising strategy for the development of analgesic treatments. Spider venom-derived peptide toxins are recognized as significant sources of Nav1.7 inhibitors. However, their development has been impeded by limited selectivity. In this study, eight peptide toxins from three distinct spider venom Nav channel families demonstrated robust inhibition of hNav1.7, rKv4.2, and rKv4.3 (rKv4.2/4.3) currents, exhibiting a similar mode of action. The analysis of structure and function relationship revealed a significant overlap in the pharmacophore responsible for inhibiting hNav1.7 and rKv4.2 by HNTX-III, although Lys25 seems to play a more pivotal role in the inhibition of rKv4.2/4.3. Pharmacophore-guided rational design is employed for the development of an mGpTx1 analogue, mGpTx1-SA, which retains its inhibition of hNav1.7 while significantly reducing its inhibition of rKv4.2/4.3 and eliminating cardiotoxicity. Moreover, mGpTx1-SA demonstrates potent analgesic effects in both inflammatory and neuropathic pain models, accompanied by an improved in vivo safety profile. The results suggest that off-target inhibition of rKv4.2/4.3 by specific spider peptide toxins targeting hNav1.7 may arise from a conserved binding motif. This insight promises to facilitate the design of hNav1.7-specific analgesics, aimed at minimizing rKv4.2/4.3 inhibition and associated toxicity, thereby enhancing their suitability for therapeutic applications.