scholarly journals Defensive Venoms: Is Pain Sufficient for Predator Deterrence?

Toxins ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 260 ◽  
Author(s):  
Crystal N. Niermann ◽  
Travis G. Tate ◽  
Amber L. Suto ◽  
Rolando Barajas ◽  
Hope A. White ◽  
...  

Pain, though unpleasant, is adaptive in calling an animal’s attention to potential tissue damage. A long list of animals representing diverse taxa possess venom-mediated, pain-inducing bites or stings that work by co-opting the pain-sensing pathways of potential enemies. Typically, such venoms include toxins that cause tissue damage or disrupt neuronal activity, rendering painful stings honest indicators of harm. But could pain alone be sufficient for deterring a hungry predator? Some venomologists have argued “no”; predators, in the absence of injury, would “see through” the bluff of a painful but otherwise benign sting or bite. Because most algogenic venoms are also toxic (although not vice versa), it has been difficult to disentangle the relative contributions of each component to predator deterrence. Southern grasshopper mice (Onychomys torridus) are voracious predators of arthropods, feeding on a diversity of scorpion species whose stings vary in painfulness, including painful Arizona bark scorpions (Centruroides sculpturatus) and essentially painless stripe-tailed scorpions (Paravaejovis spinigerus). Moreover, southern grasshopper mice have evolved resistance to the lethal toxins in bark scorpion venom, rendering a sting from these scorpions painful but harmless. Results from a series of laboratory experiments demonstrate that painful stings matter. Grasshopper mice preferred to prey on stripe-tailed scorpions rather than bark scorpions when both species could sting; the preference disappeared when each species had their stingers blocked. A painful sting therefore appears necessary for a scorpion to deter a hungry grasshopper mouse, but it may not always be sufficient: after first attacking and consuming a painless stripe-tailed scorpion, many grasshopper mice went on to attack, kill, and eat a bark scorpion even when the scorpion was capable of stinging. Defensive venoms that result in tissue damage or neurological dysfunction may, thus, be required to condition greater aversion than venoms causing pain alone.

2021 ◽  
Author(s):  
Tarek Mohamed Abd El-Aziz ◽  
Yucheng Xiao ◽  
Jake Kline ◽  
Harold Gridley ◽  
Alyse Heaston ◽  
...  

The voltage-gated sodium channel Nav1.8 is linked to neuropathic and inflammatory pain, high-lighting the potential to serve as a drug target. However, the biophysical mechanisms that regu-late Nav1.8 activation and inactivation gating are not completely understood. Progress has been hindered by a lack of biochemical tools for examining Nav1.8 gating mechanisms. Arizona bark scorpion (Centruroides sculpturatus) venom proteins inhibit Nav1.8 and block pain in grasshopper mice (Onychomys torridus). These proteins provide tools for examining Nav1.8 structure-activity relationships. To identify proteins that inhibit Nav1.8 activity, venom samples were fractioned using liquid chromatography (reversed phase and ion exchange). A recombinant Nav1.8 clone expressed in ND7/23 cells was used to identify subfractions that inhibited Nav1.8 Na+ current. Mass spectrometry-based bottom-up proteomic analyses identified unique peptides from inhibi-tory subfractions. A search of the peptides against the AZ bark scorpion venom gland transcrip-tome revealed four novel proteins between 40 and 60% conserved with venom proteins from scorpions in four genera (Centruroides, Parabuthus, Androctonus, and Tityus). Ranging from 63 to 82 amino acids, each primary structure includes 8 cysteines and a CXCE motif where X = an aro-matic residue (tryptophan, tyrosine or phenylalanine). Electrophysiology data demonstrated that the inhibitory effects of bioactive subfractions can be removed by hyperpolarizing the channels, suggesting that proteins may function as gating modifiers as opposed to pore blockers.


Neurosurgery ◽  
2001 ◽  
Vol 48 (6) ◽  
pp. 1393-1401 ◽  
Author(s):  
Rene O. Sanchez Mejia ◽  
Victor O. Ona ◽  
Mingwei Li ◽  
Robert M. Friedlander

Shock ◽  
2010 ◽  
Vol 33 (2) ◽  
pp. 189-196 ◽  
Author(s):  
Axel Menzebach ◽  
Stefan Bergt ◽  
Philine von Waldthausen ◽  
Christian Dinu ◽  
Gabriele Nöldge-Schomburg ◽  
...  

2018 ◽  
Vol 638 ◽  
pp. 52-57 ◽  
Author(s):  
Edson Norberto Carcamo-Noriega ◽  
Timoteo Olamendi-Portugal ◽  
Rita Restano-Cassulini ◽  
Ashlee Rowe ◽  
Selene Jocelyn Uribe-Romero ◽  
...  

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