Project description:Spiders have distinct capture prey behaviors selected along Araneae´s evolutive history, but mainly based on the use of venom for prey paralysis. Uloboridae spiders lost the venom glands secondarily in evolution. Due to that they extensively wrap prey with silk to paralyze and begin digestion. During the extra-oral digestion, the digestive fluid very efficiently performs the liquefaction of both the prey and the AcSp2 spidroins from the web fibers. Despite the efficiency of this process, the cocktail of enzymes involved in digestion in Uloboridae spiders is unknown. In this study, we evaluated the protein content in the midgut of Uloborus sp. using enzymatic, proteomic, and phylogenetic analysis approaches. Hydrolases as peptidases (endo and exopeptidases: cysteine, serine and metallopeptidases), carbohydrases (alpha-amylase, chitinase, alpha-mannosidase), and lipases were biochemically assayed; 50 proteins, annotated as enzymes, structural proteins, and toxins, were identified. This is the first characterization of the molecules involved in the digestive process and the midgut protein content of a nonvenomous spider.
Project description:Spiders are a highly diverse group of arthropods that occur in most habitats on land. Notably, spiders have significant ecological impact as predators because of their extraordinary prey capture adaptations, venom and silk. Spider venom is among the most heterogeneous animal venoms and has pharmacological applications, while spider silk is characterized by great toughness with potential for biomaterial application. We describe the genome sequences of two spiders representing two major taxonomic groups, the social velvet spider Stegodyphus mimosarum (Araneomorphae), and the Brazilian white-knee tarantula Acanthoscurria geniculata (Mygalomorphae). We annotate genes using a combination of transcriptomic and in-depth proteomic analyses. The genomes are large (2.6 Gb and 6 Gb, respectively) with short exons and long introns and approximately 50% repeats, reminiscent of typical mammalian genomes. Phylogenetic analyses show that spiders and ticks are sister groups outgrouped by mites, and phylogenetic dating using a molecular clock dates separation of velvet spider and tarantula at 270 my. Based on the genomes and proteomes, we characterize the genetic basis of venom and silk production of both species in detail. Venom protein composition differs markedly between the two spiders, with lipases as the most abundant protein in the velvet spider and present only at low concentration in tarantula. Venom in both spiders contains proteolytic enzymes, and our analyses suggest that these enzymes target and process precursor peptides that subsequently mediate the toxic effects of venom. Complete analysis of silk genes reveal a diverse suite of silk proteins in the velvet spider including novel types of spidroins, and dynamic evolution of major ampullate spidroin genes, whereas silk protein diversity in tarantula is far less complex. The difference in silk proteins between species is consistent with a more complex silk gland morpholgy and use of three-dimentional capture webs consisting of multiple silk types in aranomorph spiders.
Project description:This dataset comprises bulk RNA sequencing of 45 samples isolated from adult female L. sclopetarius spiders. The samples include spider abdomen (5 replicates), head (5), major ampullate glands (5), minor ampullate glands (5), aggregate glands (5), tubuliform glands (3), and major ampullate gland cut into three parts, i.e., tail (6), sac (6) and duct (5).
Project description:Callobius koreanus (C.koreanus) is a wandering spider and a member of the Amaurobiidae family, infraorder Araneae. RNA-sequencing was performend for venom gland tissue and whole body except venom gland.
Project description:Spiders are renowned for their efficient capture of flying insects using intricate aerial webs. How the spider nervous systems evolved to cope with this specialized hunting strategy and various environmental clues in an aerial space remains unknown. Here, we report a brain cell atlas of >30,000 single-cell transcriptomes from a web-building spider (Hylyphantes graminicola). Our analysis revealed the preservation of ancestral neuron types in spiders, including the potential coexistence of noradrenergic and octopaminergic neurons, and many peptidergic neuronal types that are lost in insects. By comparing the genome of two newly sequenced plesiomorphic burrowing spiders with three aerial web-building spiders, we found that the positively selected genes in the ancestral branch of web-building spiders were preferentially expressed (42%) in the brain, especially in the three mushroom body-like neuronal types. By gene enrichment analysis and RNAi experiments, these genes were suggested to be involved in the learning and memory pathway and may influence the spiders’ web-building and hunting behavior. Our results provide key sources for understanding the evolution of behavior in spiders and reveal how molecular evolution drives neuron innovation and the diversification of associated complex behaviors.
Project description:Spiders are insect predators and their venoms are important to prey capture. Spider venomshave several potential applications as pharmaceutical compounds and insecticides. However,transcriptomic and proteomic analyses of the digestive system (DS) of spiders show that DS is also a rich source of new inhibitor molecules. Biochemical, transcriptomic and proteomic data of crude DS extracts show the presence of molecules with inhibitor potential in the spider Nephilingis cruentata. Therefore, the aims of this work were to isolate and characterize molecules with serine peptidase inhibitory activity. The DS of fasting adult females was homogenized under acidic conditions and subjected to heat treatment. After that, samples were submitted to ion exchange batch and high-performance reverse-phase chromatography. The fractions with inhibitory activity were confirmed by mass spectrometry, identifying 6 molecules with inhibitor potential. The inhibitor Nc6834 was kinetically characterized, showing a KD value of 30.25 nM ± 8.13. Analysis of the tertiary structure by molecular modeling using Alpha-Fold2 indicates that the inhibitor Nc6834 structurally belongs to theMIT1-like atracotoxin family. This is the first time that a serine peptidase inhibitory function is attributed to this structural family and the reactive site inhibitor residue is identified. Sequence analysis indicates that these molecules may be present in the DS of other spiders.
Project description:Orb-weaving spiders use a highly strong, sticky and elastic web to catch their prey. These web properties alone would be enough for the entrapment of prey; however, these spiders may be hiding venomous secrets in the web, which current research is revealing. Here, we provide strong proteotranscriptomic evidence for the presence of toxin/neurotoxin-like proteins, defensins and proteolytic enzymes on the web silk from Nephila clavipes spider. The results from quantitative-based transcriptomics and proteomic approaches showed that silk-producing glands produce an extensive repertoire of toxin/neurotoxin-like proteins, similar to those already reported in spider venoms. Meanwhile, the insect toxicity results demonstrated that these toxic components can be lethal and/or paralytic chemical weapons used for prey capture on the web; and the presence of fatty acids in the web may be responsible mechanism for open the way to the web-toxins for accessing the interior of prey's body, as showed here. Comparative phylogenomic-level evolutionary analyses revealed orthologous genes among two spider groups - Araneomorphae and Mygalomorphae; and the findings showed protein sequences similar to toxins found in the taxa Scorpiones and Hymenoptera in addition to Araneae. Overall, these data represent a valuable resource to further investigate other spider web toxin systems; these data also suggest that N. clavipes web is not a passive mechanical trap for prey capture, but it exerts an active role in prey paralysis/killing using a series of neurotoxins.
Project description:In this study, we profiled the transcriptional changes in a polyphagous spider mite, Tetranychus urticae, after adaptation to spatial and tempospatial stress. We show heritable down-regulation of genes encoding for core enzymes involved in the citric acid and gluconeogenesis/glycolyse pathways (glucose 6-phosphatase among others). Additionally, we observe heritable transcriptional changes in amino acid pathways (methionine, tyrosine and phenylalanine) and in laterally acquired genes from bacteria (cobalamin-independent methionine synthase). By similiar study results in other organisms, we argue that these heritable transcriptional changes (partially) underpin the changed life history traits observed in our experimental evolution set-up.
Project description:Spider venom neurotoxins and cytolytic peptides are expressed as elongated precursor peptides, which are post-translationally processed by proteases to yield the active mature peptides. The recognition motifs for these processing proteases, first published more than ten years ago, include the Processing Quadruplet Motif (PQM) and the inverted Processing Quadruplet Motif (iPQM). However, the identification of the relevant proteases was still pending. Here we describe the purification of a neurotoxin precursor processing protease from the venom of the spider Cupiennius salei. The chymotrypsin – like serine protease is a 28 kDa heterodimer with optimum activity at venom’s pH of 6.0. We designed multiple synthetic peptides mimicking the predicted cleavage sites of neurotoxin precursors. Using these peptides as substrates, we confirm the biochemical activity of the protease in propeptide removal from neurotoxin precursors by cleavage C-terminal of the PQM. Furthermore, the PQM protease also cleaves the iPQM relevant for heterodimerization of a subgroup of neurotoxins. An involvement in the maturing of cytolytic peptides is very likely, due to high similarity of present protease recognition motifs. Finally, bioinformatics analysis, identifying sequences of homolog proteins from 18 spiders of 9 families, demonstrate the wide distribution and importance of the isolated enzyme for spiders. In summary, we establish the first example of a PQM protease, essential for maturing of spider venom neurotoxins. In the future, the here described protease may be established as powerful tool for production strategies of recombinant toxic peptides, adapted to the maturing of spider venom toxins.