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Cone snail

Daryl C Yang, Jennifer R Deuis, Daniel Dashevsky, James Dobson, Timothy N W Jackson, Andreas Brust, Bing Xie, Ivan Koludarov, Jordan Debono, Iwan Hendrikx, Wayne C Hodgson, Peter Josh, Amanda Nouwens, Gregory J Baillie, Timothy J C Bruxner, Paul F Alewood, Kelvin Kok Peng Lim, Nathaniel Frank, Irina Vetter, Bryan G Fry
Millions of years of evolution have fine-tuned the ability of venom peptides to rapidly incapacitate both prey and potential predators. Toxicofera reptiles are characterized by serous-secreting mandibular or maxillary glands with heightened levels of protein expression. These glands are the core anatomical components of the toxicoferan venom system, which exists in myriad points along an evolutionary continuum. Neofunctionalisation of toxins is facilitated by positive selection at functional hotspots on the ancestral protein and venom proteins have undergone dynamic diversification in helodermatid and varanid lizards as well as advanced snakes...
October 18, 2016: Toxins
Briony E Forbes
The last two years of insulin-like growth factor (IGF) research has yielded a vast literature highlighting the central role IGFs factors play in processes such as development, growth, aging and neurological function. It also provides our latest understanding of how IGF system perturbation is linked to diseases including growth deficiency, cancer, and neurological and cardiovascular diseases. A snapshot of the highlights is presented in this review, focussing on the topics of IGFs and growth, comparative and structural biology to understand insulin-like peptide function, IGFs and cancer, and IGFs and neurological function...
September 30, 2016: Growth Hormone & IGF Research
Muriel Primon-Barros, Alexandre José Macedo
Microbial infections affect people worldwide, causing diseases with significant impact on public health, indicating the need for research and development of new antimicrobial agents. Animal venoms represent a vast and largely unexploited source of biologically active molecules with attractive candidates for the development of novel therapeutics. Venoms consist of complex mixtures of molecules, including antimicrobial peptides (AMPs). Since the discovery of AMPs, they have been studied as promising new antimicrobial drugs...
September 30, 2016: Current Topics in Medicinal Chemistry
Frédéric Ducancel
Animal venoms are complex chemical cocktails, comprising a wide range of biologically active reticulated peptides that target with high selectivity and efficacy a variety of enzymes, membrane receptors, ion channels...Venoms can therefore be seen as large natural libraries of biologically active molecules that are continuously selected and highly refined by the evolution process, up to the point where every molecule is endowed with pharmacological properties that are highly valuable in the context of human use and drug development...
2016: Biologie Aujourd'hui
John G Menting, Joanna Gajewiak, Christopher A MacRaild, Danny Hung-Chieh Chou, Maria M Disotuar, Nicholas A Smith, Charleen Miller, Judit Erchegyi, Jean E Rivier, Baldomero M Olivera, Briony E Forbes, Brian J Smith, Raymond S Norton, Helena Safavi-Hemami, Michael C Lawrence
Insulins in the venom of certain fish-hunting cone snails facilitate prey capture by rapidly inducing hypoglycemic shock. One such insulin, Conus geographus G1 (Con-Ins G1), is the smallest known insulin found in nature and lacks the C-terminal segment of the B chain that, in human insulin, mediates engagement of the insulin receptor and assembly of the hormone's hexameric storage form. Removal of this segment (residues B23-B30) in human insulin results in substantial loss of receptor affinity. Here, we found that Con-Ins G1 is monomeric, strongly binds the human insulin receptor and activates receptor signaling...
October 2016: Nature Structural & Molecular Biology
B R Green, B M Olivera
The venoms of cone snails provide a rich source of neuroactive peptides (conotoxins). Several venom peptide families have been identified that are either agonists (ι- and δ-conotoxins) or antagonists (μ- and μO-conotoxins) of voltage-gated sodium channels (VGSCs). Members of these conotoxin classes have been integral in identifying and characterizing specific neurotoxin binding sites on the channel. Furthermore, given the specificity of some of these peptides for one sodium channel subtype over another, conotoxins have also proven useful in exploring differences between VGSC subtypes...
2016: Current Topics in Membranes
Helena Safavi-Hemami, Aiping Lu, Qing Li, Alexander E Fedosov, Jason Biggs, Patrice Showers Corneli, Jon Seger, Mark Yandell, Baldomero M Olivera
A specialized insulin was recently found in the venom of a fish-hunting cone snail, Conus geographus Here we show that many worm-hunting and snail-hunting cones also express venom insulins, and that this novel gene family has diversified explosively. Cone snails express a highly conserved insulin in their nerve ring; presumably this conventional signaling insulin is finely tuned to the Conus insulin receptor, which also evolves very slowly. By contrast, the venom insulins diverge rapidly, apparently in response to biotic interactions with prey and also possibly the cones' own predators and competitors...
November 2016: Molecular Biology and Evolution
Stephen Estes, Liana Artinian, Vincent Rehder
Carbon monoxide (CO) is physiologically produced via heme degradation by heme oxygenase enzymes. Whereas CO has been identified as an important physiological signaling molecule, the roles it plays in neuronal development and regeneration are poorly understood. During these events, growth cones guide axons through a rich cellular environment to locate target cells and establish synaptic connections. Previously, we have shown that another gaseous signaling molecule, nitric oxide (NO), has potent effects on growth cone motility...
August 11, 2016: Developmental Neurobiology
Mark A Phuong, Gusti N Mahardika, Michael E Alfaro
BACKGROUND: Although diet is believed to be a major factor underlying the evolution of venom, few comparative studies examine both venom composition and diet across a radiation of venomous species. Cone snails within the family, Conidae, comprise more than 700 species of carnivorous marine snails that capture their prey by using a cocktail of venomous neurotoxins (conotoxins or conopeptides). Venom composition across species has been previously hypothesized to be shaped by (a) prey taxonomic class (i...
2016: BMC Genomics
Mohammed Abdel-Wahab, Masahiro Miyashita, Atsushi Kitanaka, Hironori Juichi, Moustafa Sarhan, Maged Fouda, Mohamed Abdel-Rahman, Samy Saber, Yoshiaki Nakagawa
Over 200 components with molecular mass ranging mainly from 400 to 4000 Da were characterized from the venom of the vermivorous cone snail Conus fulgetrum that inhabit Egyptian Red Sea. One major component having a molecular mass of 2946 Da was purified by HPLC, and its primary structure was determined by a combination of Edman degradation and MS/MS analysis.
October 2016: Bioscience, Biotechnology, and Biochemistry
Soohyun Kwon, Frank Bosmans, Quentin Kaas, Olivier Cheneval, Anne C Conibear, K Johan Rosengren, Conan K Wang, Christina I Schroeder, David J Craik
Disulfide-rich peptides isolated from cone snails are of great interest as drug leads due to their high specificity and potency toward therapeutically relevant ion channels and receptors. They commonly contain the inhibitor cystine knot (ICK) motif comprising three disulfide bonds forming a knotted core. Here we report the successful enzymatic backbone cyclization of an ICK-containing peptide κ-PVIIA, a 27-amino acid conopeptide from Conus purpurascens, using a mutated version of the bacterial transpeptidase, sortase A...
October 2016: Biotechnology and Bioengineering
Chao Peng, Ge Yao, Bing-Miao Gao, Chong-Xu Fan, Chao Bian, Jintu Wang, Ying Cao, Bo Wen, Yabing Zhu, Zhiqiang Ruan, Xiaofei Zhao, Xinxin You, Jie Bai, Jia Li, Zhilong Lin, Shijie Zou, Xinhui Zhang, Ying Qiu, Jieming Chen, Steven L Coon, Jiaan Yang, Ji-Sheng Chen, Qiong Shi
BACKGROUND: The venom of predatory marine cone snails mainly contains a diverse array of unique bioactive peptides commonly referred to as conopeptides or conotoxins. These peptides have proven to be valuable pharmacological probes and potential drugs because of their high specificity and affinity to important ion channels, receptors and transporters of the nervous system. Most previous studies have focused specifically on the conopeptides from piscivorous and molluscivorous cone snails, but little attention has been devoted to the dominant vermivorous species...
2016: GigaScience
Marco A De León-Nava, Eunice Romero-Núñez, Angélica Luna-Nophal, Johanna Bernáldez-Sarabia, Liliana N Sánchez-Campos, Alexei F Licea-Navarro, Jorge Morales-Montor, Saé Muñiz-Hernández
Toxins that are secreted by cone snails are small peptides that are used to treat several diseases. However, their effects on parasites with human and veterinary significance are unknown. Toxoplasma gondii is an opportunistic parasite that affects approximately 30% of the world's population and can be lethal in immunologically compromised individuals. The conventional treatment for this parasitic infection has remained the same since the 1950s, and its efficacy is limited to the acute phase of infection. These findings have necessitated the search for new drugs that specifically target T...
April 2016: Marine Drugs
Helena Safavi-Hemami, Qing Li, Ronneshia L Jackson, Albert S Song, Wouter Boomsma, Pradip K Bandyopadhyay, Christian W Gruber, Anthony W Purcell, Mark Yandell, Baldomero M Olivera, Lars Ellgaard
Formation of correct disulfide bonds in the endoplasmic reticulum is a crucial step for folding proteins destined for secretion. Protein disulfide isomerases (PDIs) play a central role in this process. We report a previously unidentified, hypervariable family of PDIs that represents the most diverse gene family of oxidoreductases described in a single genus to date. These enzymes are highly expressed specifically in the venom glands of predatory cone snails, animals that synthesize a remarkably diverse set of cysteine-rich peptide toxins (conotoxins)...
March 22, 2016: Proceedings of the National Academy of Sciences of the United States of America
Joel Castro, Andrea M Harrington, Sonia Garcia-Caraballo, Jessica Maddern, Luke Grundy, Jingming Zhang, Guy Page, Paul E Miller, David J Craik, David J Adams, Stuart M Brierley
OBJECTIVE: α-Conotoxin Vc1.1 is a small disulfide-bonded peptide from the venom of the marine cone snail Conus victoriae. Vc1.1 has antinociceptive actions in animal models of neuropathic pain, but its applicability to inhibiting human dorsal root ganglion (DRG) neuroexcitability and reducing chronic visceral pain (CVP) is unknown. DESIGN: We determined the inhibitory actions of Vc1.1 on human DRG neurons and on mouse colonic sensory afferents in healthy and chronic visceral hypersensitivity (CVH) states...
February 17, 2016: Gut
A I Kuzmenkov, E V Grishin, A A Vassilevski
Potassium (K+) channels are a widespread superfamily of integral membrane proteins that mediate selective transport of K+ ions through the cell membrane. They have been found in all living organisms from bacteria to higher multicellular animals, including humans. Not surprisingly, K+ channels bind ligands of different nature, such as metal ions, low molecular mass compounds, venom-derived peptides, and antibodies. Functionally these substances can be K+ channel pore blockers or modulators. Representatives of the first group occlude the channel pore, like a cork in a bottle, while the second group of ligands alters the operation of channels without physically blocking the ion current...
December 2015: Biochemistry. Biokhimii︠a︡
Johanna Bernáldez, Samanta Jiménez, Luis Javier González, Jesús Noda Ferro, Enrique Soto, Emilio Salceda, Daniela Chávez, Manuel B Aguilar, Alexei Licea-Navarro
A novel conotoxin, named as PiVIIA, was isolated from the venom of Conus princeps, a marine predatory cone snail collected in the Pacific Southern Coast of Mexico. Chymotryptic digest of the S-alkylated peptide in combination with liquid chromatography coupled to tandem mass spectrometry, were used to define the sequencing of this peptide. Eleven N-terminal amino acids were verified by automated Edman degradation. PiVIIA is a 25-mer peptide (CDAOTHYCTNYWγCCSGYCγHSHCW) with six cysteine residues forming three disulphide bonds, a hydroxyproline (O) and two gamma carboxyglutamic acid (γ) residues...
February 2016: Toxins
Samuel S Espino, Taleen Dilanyan, Julita S Imperial, Manuel B Aguilar, Russell W Teichert, Pradip Bandyopadhyay, Baldomero M Olivera
Cone snails in the Virgiconus clade prey on marine worms. Here, we identify six related conotoxins in the O1-superfamily from three species in this clade, Conus virgo, Conus terebra and Conus kintoki. One of these peptides, vi6a, was directly purified from the venom of C. virgo by following its activity using calcium imaging of dissociated mouse dorsal root ganglion (DRG) neurons. The purified peptide was biochemically characterized, synthesized and tested for activity in mice. Hyperactivity was observed upon both intraperitoneal and intracranial injection of the peptide...
April 2016: Toxicon: Official Journal of the International Society on Toxinology
Brad R Green, Joanna Gajewiak, Sandeep Chhabra, Jack J Skalicky, Min-Min Zhang, Jean E Rivier, Grzegorz Bulaj, Baldomero M Olivera, Doju Yoshikami, Raymond S Norton
Cone snail toxins are well known blockers of voltage-gated sodium channels, a property that is of broad interest in biology and therapeutically in treating neuropathic pain and neurological disorders. Although most conotoxin channel blockers function by direct binding to a channel and disrupting its normal ion movement, conotoxin μO§-GVIIJ channel blocking is unique, using both favorable binding interactions with the channel and a direct tether via an intermolecular disulfide bond. Disulfide exchange is possible because conotoxin μO§-GVIIJ contains anS-cysteinylated Cys-24 residue that is capable of exchanging with a free cysteine thiol on the channel surface...
March 25, 2016: Journal of Biological Chemistry
J R Prashanth, S Dutertre, A H Jin, V Lavergne, B Hamilton, F C Cardoso, J Griffin, D J Venter, P F Alewood, R J Lewis
Venoms comprise of complex mixtures of peptides evolved for predation and defensive purposes. Remarkably, some carnivorous cone snails can inject two distinct venoms in response to predatory or defensive stimuli, providing a unique opportunity to study separately how different ecological pressures contribute to toxin diversification. Here, we report the extraordinary defensive strategy of the Rhizoconus subgenus of cone snails. The defensive venom from this worm-hunting subgenus is unusually simple, almost exclusively composed of αD-conotoxins instead of the ubiquitous αA-conotoxins found in the more complex defensive venom of mollusc- and fish-hunting cone snails...
January 2016: Molecular Ecology
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