cone snails
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2022 ◽  
Author(s):  
Ksenia G Kuznetsova ◽  
Sofia S Zvonareva ◽  
Rustam Ziganshin ◽  
Elena S Mekhova ◽  
Polina Yu Dgebuadze ◽  
...  

Venoms of predatory marine cone snails (the family Conidae, order Neogastropoda) are intensely studied because of the broad range of biomedical applications of the neuropeptides that they contain, conotoxins. Meanwhile anatomy in some other neogastropod lineages strongly suggests that they have evolved similar venoms independently of cone snails, nevertheless their venom composition remains unstudied. Here we focus on the most diversified of these lineages, the genus Vexillum (the family Costellariidae). We have generated comprehensive multi-specimen, multi-tissue RNA-Seq data sets for three Vexillum species, and supported our findings in two species by proteomic profiling. We show that venoms of Vexillum are dominated by highly diversified short cysteine-rich peptides that in many aspects are very similar to conotoxins. Vexitoxins possess the same precursor organization, display overlapping cysteine frameworks and share several common post-translational modifications with conotoxins. Some vexitoxins show detectable sequence similarity to conotoxins, and are predicted to adopt similar domain conformations, including a pharmacologically relevant inhibitory cysteine-know motif (ICK). The tubular gL of Vexillum is a notably more recent evolutionary novelty than the conoidean venom gland. Thus, we hypothesize lower divergence between the toxin genes, and their somatic counterparts compared to that in conotoxins, and we find support for this hypothesis in the molecular evolution of the vexitoxin cluster V027. We use this example to discuss how future studies on vexitoxins can inform origin and evolution of conotoxins, and how they may help addressing standing questions in venom evolution.


2021 ◽  
Vol 288 (1954) ◽  
pp. 20211017
Author(s):  
Alexander Fedosov ◽  
Paul Zaharias ◽  
Nicolas Puillandre

Marine gastropods of the genus Conus are renowned for their remarkable diversity and deadly venoms. While Conus venoms are increasingly well studied for their biomedical applications, we know surprisingly little about venom composition in other lineages of Conidae. We performed comprehensive venom transcriptomic profiling for Conasprella coriolisi and Pygmaeconus traillii , first time for both respective genera. We complemented reference-based transcriptome annotation by a de novo toxin prediction guided by phylogeny, which involved transcriptomic data on two additional ‘divergent’ cone snail lineages, Profundiconus , and Californiconus . We identified toxin clusters (SSCs) shared among all or some of the four analysed genera based on the identity of the signal region—a molecular tag present in toxins. In total, 116 and 98 putative toxins represent 29 and 28 toxin gene superfamilies in Conasprella and Pygmaeconus , respectively; about quarter of these only found by semi-manual annotation of the SSCs. Two rare gene superfamilies, originally identified from fish-hunting cone snails, were detected outside Conus rather unexpectedly, so we further investigated their distribution across Conidae radiation. We demonstrate that both these, in fact, are ubiquitous in Conidae, sometimes with extremely high expression. Our findings demonstrate how a phylogeny-aware approach circumvents methodological caveats of similarity-based transcriptome annotation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. W. A. Himaya ◽  
Ai-Hua Jin ◽  
Brett Hamilton ◽  
Subash K. Rai ◽  
Paul Alewood ◽  
...  

AbstractThe venom duct origins of predatory and defensive venoms has not been studied for hook-and-line fish hunting cone snails despite the pharmacological importance of their venoms. To better understand the biochemistry and evolution of injected predatory and defensive venoms, we compared distal, central and proximal venom duct sections across three specimens of C. striatus (Pionoconus) using proteomic and transcriptomic approaches. A total of 370 conotoxin precursors were identified from the whole venom duct transcriptome. Milked defensive venom was enriched with a potent cocktail of proximally expressed inhibitory α-, ω- and μ-conotoxins compared to milked predatory venom. In contrast, excitatory κA-conotoxins dominated both the predatory and defensive venoms despite their distal expression, suggesting this class of conotoxin can be selectively expressed from the same duct segment in response to either a predatory or defensive stimuli. Given the high abundance of κA-conotoxins in the Pionoconus clade, we hypothesise that the κA-conotoxins have evolved through adaptive evolution following their repurposing from ancestral inhibitory A superfamily conotoxins to facilitate the dietary shift to fish hunting and species radiation in this clade.


2021 ◽  
Vol 12 ◽  
Author(s):  
Zhenjian Lin ◽  
Joshua P. Torres ◽  
Maren Watkins ◽  
Noemi Paguigan ◽  
Changshan Niu ◽  
...  

Venomous molluscs (Superfamily Conoidea) comprise a substantial fraction of tropical marine biodiversity (>15,000 species). Prior characterization of cone snail venoms established that bioactive venom components used to capture prey, defend against predators and for competitive interactions were relatively small, structured peptides (10–35 amino acids), most with multiple disulfide crosslinks. These venom components (“conotoxins, conopeptides”) have been widely studied in many laboratories, leading to pharmaceutical agents and probes. In this review, we describe how it has recently become clear that to varying degrees, cone snail venoms also contain bioactive non-peptidic small molecule components. Since the initial discovery of genuanine as the first bioactive venom small molecule with an unprecedented structure, a broad set of cone snail venoms have been examined for non-peptidic bioactive components. In particular, a basal clade of cone snails (Stephanoconus) that prey on polychaetes produce genuanine and many other small molecules in their venoms, suggesting that this lineage may be a rich source of non-peptidic cone snail venom natural products. In contrast to standing dogma in the field that peptide and proteins are predominantly used for prey capture in cone snails, these small molecules also contribute to prey capture and push the molecular diversity of cone snails beyond peptides. The compounds so far characterized are active on neurons and thus may potentially serve as leads for neuronal diseases. Thus, in analogy to the incredible pharmacopeia resulting from studying venom peptides, these small molecules may provide a new resource of pharmacological agents.


Toxins ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 270
Author(s):  
Henrike Schmidtberg ◽  
Björn M. von Reumont ◽  
Sarah Lemke ◽  
Andreas Vilcinskas ◽  
Tim Lüddecke

Spiders are one of the most successful groups of venomous animals, but surprisingly few species have been examined in sufficient detail to determine the structure of their venom systems. To learn more about the venom system of the family Araneidae (orb-weavers), we selected the wasp spider (Argiope bruennichi) and examined the general structure and morphology of the venom apparatus by light microscopy. This revealed morphological features broadly similar to those reported in the small number of other spiders subject to similar investigations. However, detailed evaluation of the venom duct revealed the presence of four structurally distinct compartments. We propose that these subunits facilitate the expression and secretion of venom components, as previously reported for similar substructures in pit vipers and cone snails.


Biomedicines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 344
Author(s):  
Anicet Ebou ◽  
Dominique Koua ◽  
Audrey Addablah ◽  
Solange Kakou-Ngazoa ◽  
Sébastien Dutertre

Despite their impressive diversity and already broad therapeutic applications, cone snail venoms have received less attention as a natural source in the investigation of antimicrobial peptides than other venomous animals such as scorpions, spiders, or snakes. Cone snails are among the largest genera (Conus sp.) of marine invertebrates, with more than seven hundred species described to date. These predatory mollusks use their sophisticated venom apparatus to capture prey or defend themselves. In-depth studies of these venoms have unraveled many biologically active peptides with pharmacological properties of interest in the field of pain management, the treatment of epilepsy, neurodegenerative diseases, and cardiac ischemia. Considering sequencing efficiency and affordability, cone snail venom gland transcriptome analyses could allow the discovery of new, promising antimicrobial peptides. We first present here the need for novel compounds like antimicrobial peptides as a viable alternative to conventional antibiotics. Secondly, we review the current knowledge on cone snails as a source of antimicrobial peptides. Then, we present the current state of the art in analytical methods applied to crude or milked venom followed by how antibacterial activity assay can be implemented for fostering cone snail antimicrobial peptides studies. We also propose a new innovative profile Hidden Markov model-based approach to annotate full venom gland transcriptomes and speed up the discovery of potentially active peptides from cone snails.


2021 ◽  
Vol 99 (9) ◽  
pp. 9-9
Author(s):  
Celia Henry Arnaud
Keyword(s):  

Marine Drugs ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 60
Author(s):  
David A. Armstrong ◽  
Ai-Hua Jin ◽  
Nayara Braga Emidio ◽  
Richard J. Lewis ◽  
Paul F. Alewood ◽  
...  

Conotoxins are disulfide-rich peptides found in the venom of cone snails. Due to their exquisite potency and high selectivity for a wide range of voltage and ligand gated ion channels they are attractive drug leads in neuropharmacology. Recently, cone snails were found to have the capability to rapidly switch between venom types with different proteome profiles in response to predatory or defensive stimuli. A novel conotoxin, GXIA (original name G117), belonging to the I3-subfamily was identified as the major component of the predatory venom of piscivorous Conus geographus. Using 2D solution NMR spectroscopy techniques, we resolved the 3D structure for GXIA, the first structure reported for the I3-subfamily and framework XI family. The 32 amino acid peptide is comprised of eight cysteine residues with the resultant disulfide connectivity forming an ICK+1 motif. With a triple stranded β-sheet, the GXIA backbone shows striking similarity to several tarantula toxins targeting the voltage sensor of voltage gated potassium and sodium channels. Supported by an amphipathic surface, the structural evidence suggests that GXIA is able to embed in the membrane and bind to the voltage sensor domain of a putative ion channel target.


Author(s):  
Baldomero M. Olivera

My path to research in neuropharmacology has been a coalescing of my training as a molecular biologist and my intense interest in an esoteric group of animals, the fish-hunting cone snails. Attempting to bridge these two disparate worlds has led me to an idiosyncratic career as a pharmacologist.


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