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:The goal of this study was to lay the groundwork for comparative transcriptomics of sex differences in the brain of wolf spiders, a non-model organism of the pyhlum Euarthropoda, by generating transcriptomes and analyzing gene expression. To examine differences in sex-differential gene expression, short read transcript sequencing and de novo transcriptome assembly were performed. Messenger RNA (mRNA) was isolated from dissected brain tissue of male and female subadult and mature wolf spiders (Schizocosa ocreata). The data consist of short read sequences for the two different life stages in each sex. Computational analyses on these data include de novo transcriptome assembly, using Trinity and CAP3 assembly suites, and differential expression analysis using the edgeR package. Sample-specific and combined transcriptomes, gene annotations, and differential expression results are described in this data note and are available from associated database submissions.
Project description:About 430 million years ago spiders and scorpions evolved from a common ancestor that had experienced a whole genome duplication (WGD) The genetic remnants of this WGD event (genes called ohnologs) can still be found in the genome of the approximately 45,000 species of these animals alive today and these ohnologs may have contributed to their adaptation and diversification. Interestingly, the WGD in arachnids like scorpions and spiders was contemporary with independent WGDs in vertebrates. This presents an opportunity to compare these events to determine if there are general principals underlying the outcomes of WGDs and their contribution to animal diversification. Therefore, the aims of this project are to identify arachnid ohnologs, explore how they have contributed to the evolutionary success of these animals, and compare the outcomes of this event to WGD in vertebrates. This includes sequencing new genomes and transcriptomes of species occupying key phylogenetic positions.
Project description:Hyaluronidases are important venom components by acting as spreading factor of neurotoxins. In several studies this spreading effect was tested on vertebrate tissue. However, data about the spreading activity on invertebrates, which are the main prey organisms of spiders, are lacking. In this study, a hyaluronidase-like enzyme was isolated from the venom of the spider Cupiennius salei. The amino acid sequence of the enzyme was solved by cDNA analysis of the venom gland transcriptome and confirmed by protein analytics. Two complex N-linked glycans, which akin honey bee hyaluronidase glycosylations, were identified by tandem mass spectrometry.
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:Prey-specialised spiders are adapted to capture specific prey items, including dangerous prey such as ants, termites or other spiders. It has been observed that the venoms of specialists are often prey-specific and less complex than those of generalists, but venom composition has not been studied in detail in prey-specialised spiders. Here, we investigated the venom of the prey-specialised white-tailed spider (Lamponidae: Lampona sp.), which utilises specialised morphological and behavioural adaptations to capture spider prey. We hypothesised Lampona spiders also possess venomic adaptations, specifically, its venom is more effective to focal spider prey due to the presence of prey-specific toxins. We analysed the venom composition using proteo-transcriptomics and taxon-specific toxicity using venom bioassays. Our analysis identified 208 putative toxin sequences, comprising 103 peptides <10 kDa and 105 proteins >10 kDa. Most peptides belonged to one of two families characterised by scaffolds containing eight or ten cysteine residues. Protein toxins showed similarity to galectins, leucine-rich repeat proteins, trypsins and neprilysins. The venom of Lampona was shown to be spider-specific, as it was more potent against the preferred spider prey than against alternative prey represented by a cricket. In contrast, the venom of a related generalist (Gnaphosidae: Gnaphosa sp.) was similarly potent against both prey types. Prey-specific Lampona toxins were found to form part of the protein (>10 kDa) fraction of the venom. These data provide insights into the molecular adaptations of venoms produced by prey-specialised spiders.