δ/ω-Plectoxin-Pt1a: an excitatory spider toxin with actions on both Ca(2+) and Na(+) channels

Towards a Sustainable Management of the Spotted-Wing Drosophila: Disclosing the Effects of Two Spider Venom Peptides on Drosophila suzukii

The spotted-wing drosophila (Drosophila suzukii) is a polyphagous pest that causes severe damage and economic losses to soft-skinned fruit production. Current control methods are dominated by inefficient cultural practices and broad-spectrum insecticides that, in addition to having toxic effects on non-target organisms, are becoming less effective due to acquired resistance. The increasing awareness of the real impact of insecticides on health and the environment has promoted the exploration of new insecticidal compounds, addressing novel molecular targets. This study explores the efficacy of two orally delivered spider venom peptides (SVPs), J-atracotoxin-Hv1c (Hv1c) and µ-theraphotoxin-Hhn2b (TRTX), to manage D. suzukii, through survival assays and the evaluation of gene expression associated with detoxification pathways. Treatment with TRTX at 111.5 µM for 48 h enhanced fly longevity compared with the control group. Gene expression analysis suggests that detoxification and stress-related mechanisms, such as expression of P450 proteins and apoptotic stimuli signaling, are triggered in D. suzukii flies in response to these treatments. Our results highlight the potential interest of SVPs to control this pest, shedding light on how to ultimately develop improved target-specific formulations.

Not so Dangerous After All? Venom Composition and Potency of the Pholcid (Daddy Long-Leg) Spider Physocyclus mexicanus

Pholcid spiders (Araneae: Pholcidae), officially "cellar spiders" but popularly known as "daddy long-legs," are renown for the potential of deadly toxic venom, even though venom composition and potency has never formally been studied. Here we detail the venom composition of male Physocyclus mexicanus using proteomic analyses and venom-gland transcriptomes ("venomics"). We also analyze the venom's potency on insects, and assemble available evidence regarding mammalian toxicity. The majority of the venom (51% of tryptic polypeptides and 62% of unique tryptic peptides) consists of proteins homologous to known venom toxins including enzymes (astacin metalloproteases, serine proteases and metalloendopeptidases, particularly neprilysins) and venom peptide neurotoxins. We identify 17 new groups of peptides (U1-17-PHTX) most of which are homologs of known venom peptides and are predicted to have an inhibitor cysteine knot fold; of these, 13 are confirmed in the proteome. Neprilysins (M13 peptidases), and astacins (M12 peptidases) are the most abundant venom proteins, respectively representing 15 and 11% of the individual proteins and 32 and 20% of the tryptic peptides detected in crude venom. Comparative evidence suggests that the neprilysin gene family is expressed in venoms across a range of spider taxa, but has undergone an expansion in the venoms of pholcids and may play a central functional role in these spiders. Bioassays of crude venoms on crickets resulted in an effective paralytic dose of 3.9 µg/g, which is comparable to that of crude venoms of Plectreurys tristis and other Synspermiata taxa. However, crickets exhibit flaccid paralysis and regions of darkening that are not observed after P. tristis envenomation. Documented bites on humans make clear that while these spiders can bite, the typical result is a mild sting with no long-lasting effects. Together, the evidence we present indicates pholcid venoms are a source of interesting new peptides and proteins, and effects of bites on humans and other mammals are inconsequential.

Protein Palmitoylation and Its Role in Bacterial and Viral Infections

S-palmitoylation is a reversible, enzymatic posttranslational modification of proteins in which palmitoyl chain is attached to a cysteine residue via a thioester linkage. S-palmitoylation determines the functioning of proteins by affecting their association with membranes, compartmentalization in membrane domains, trafficking, and stability. In this review, we focus on S-palmitoylation of proteins, which are crucial for the interactions of pathogenic bacteria and viruses with the host. We discuss the role of palmitoylated proteins in the invasion of host cells by bacteria and viruses, and those involved in the host responses to the infection. We highlight recent data on protein S-palmitoylation in pathogens and their hosts obtained owing to the development of methods based on click chemistry and acyl-biotin exchange allowing proteomic analysis of protein lipidation. The role of the palmitoyl moiety present in bacterial lipopolysaccharide and lipoproteins, contributing to infectivity and affecting recognition of bacteria by innate immune receptors, is also discussed.

Plectreurys tristis venome: A proteomic and transcriptomic analysis

Spider venoms are complex cocktails rich in peptides, proteins and organic molecules that collectively act to immobilize prey. Venoms of the primitive hunting spider, Plectreurys tristis, have numerous neurotoxic peptides called "plectoxins" (PLTX), a unique acylpolyamine called bis(agmatine)oxalamide, and larger unidentified protein components. These spiders also have unconventional multi-lobed venom glands. Inspired by these unusual characteristics and their phylogenetic position as Haplogynes, we have partially characterized the venome of P. tristis using combined transcriptomic and proteomic methods. With these analyses we found known venom neurotoxins U1-PLTX-Pt1a, U3-PLTX-Pt1a, and we discovered new groups of potential neurotoxins, expanding the U1- and ω-PLTX families and adding U4-through U9-PLTX as six new groups. The venom also contains proteins that are homologs of astacin metalloproteases that, combined with venom peptides, make up 94% of components detected in crude venom, while the remaining 6% is a single undescribed protein with unknown function. Other proteins detected in the transcriptome were found to be members of conserved gene families and make up 20% of the transcripts. These include cDNA sequences that match venom proteins from Mesobuthus and Hottentotta scorpions, Loxosceles and Dysdera spiders, and also salivary and secreted peptide sequences from Ixodes, Amblyomma and Rhipicephalus ticks. Finally, we show that crude venom has neurotoxic effects and an effective paralytic dose on crickets of 3.3µg/gm.