Mutation, Duplication, and More in the Evolution of Venomous Animals and Their Toxins

Malhotra, Anita

doi:10.1007/978-94-007-6727-0_5-1

Cited by 5 publications

(5 citation statements)

References 66 publications

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“…Our present finding, however, suggests that the PLA 2 gene in at least one cobra species underwent purifying selection instead. Based on the observed phenomenon, we speculate a possible scenario where post-speciation niche shifts subjected the PLA 2 multigene to the birth-and-death and “selective sieve” processes of gene duplication, divergence, and loss, in a way similar to the evolution of the elapid three-finger toxins as reported previously [ 63 , 64 ]. Depending on the functionality of the PLA 2 , genes that are no longer effective in subduing new prey species or deterring predators were lost as in pseudogenization—a more common fate for a duplicated gene actually.…”

Section: Resultssupporting

confidence: 73%

A Neurotoxic Snake Venom without Phospholipase A2: Proteomics and Cross-Neutralization of the Venom from Senegalese Cobra, Naja senegalensis (Subgenus: Uraeus)

Wong

Tan

et al. 2021

Toxins

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The Senegalese cobra, Naja senegalensis, is a non-spitting cobra species newly erected from the Naja haje complex. Naja senegalensis causes neurotoxic envenomation in Western Africa but its venom properties remain underexplored. Applying a protein decomplexation proteomic approach, this study unveiled the unique complexity of the venom composition. Three-finger toxins constituted the major component, accounting for 75.91% of total venom proteins. Of these, cardiotoxin/cytotoxin (~53%) and alpha-neurotoxins (~23%) predominated in the venom proteome. Phospholipase A2, however, was not present in the venom, suggesting a unique snake venom phenotype found in this species. The venom, despite the absence of PLA2, is highly lethal with an intravenous LD50 of 0.39 µg/g in mice, consistent with the high abundance of alpha-neurotoxins (predominating long neurotoxins) in the venom. The hetero-specific VINS African Polyvalent Antivenom (VAPAV) was immunoreactive to the venom, implying conserved protein antigenicity in the venoms of N. senegalensis and N. haje. Furthermore, VAPAV was able to cross-neutralize the lethal effect of N. senegalensis venom but the potency was limited (0.59 mg venom completely neutralized per mL antivenom, or ~82 LD50 per ml of antivenom). The efficacy of antivenom should be further improved to optimize the treatment of cobra bite envenomation in Africa.

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Section: Resultssupporting

confidence: 73%

A Neurotoxic Snake Venom without Phospholipase A2: Proteomics and Cross-Neutralization of the Venom from Senegalese Cobra, Naja senegalensis (Subgenus: Uraeus)

Wong

Tan

et al. 2021

Toxins

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“…Venom variability is a ubiquitous phenomenon and occurs at different taxonomic levels, including intraspecific [40]. This high degree of venom variability is the result of gene duplication and functional divergence that has led to the rapid evolution of venom proteins [41,42]. The implications of venom variation on pathological effects and management of snakebite are of serious concern and need urgent attention [18,24,[43][44][45][46][47].…”

Section: Discussionmentioning

confidence: 99%

Multilevel Comparison of Indian Naja Venoms and Their Cross-Reactivity with Indian Polyvalent Antivenoms

Deka

Bhatia

Santra

et al. 2023

Toxins

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Snake envenoming is caused by many biological species, rather than a single infectious agent, each with a multiplicity of toxins in their venom. Hence, developing effective treatments is challenging, especially in biodiverse and biogeographically complex countries such as India. The present study represents the first genus-wide proteomics analysis of venom composition across Naja species (N. naja, N. oxiana, and N. kaouthia) found in mainland India. Venom proteomes were consistent between individuals from the same localities in terms of the toxin families present, but not in the relative abundance of those in the venom. There appears to be more compositional variation among N. naja from different locations than among N. kaouthia. Immunoblotting and in vitro neutralization assays indicated cross-reactivity with Indian polyvalent antivenom, in which antibodies raised against N. naja are present. However, we observed ineffective neutralization of PLA2 activities of N. naja venoms from locations distant from the source of immunizing venoms. Antivenom immunoprofiling by antivenomics revealed differential antigenicity of venoms from N. kaouthia and N. oxiana, and poor reactivity towards 3FTxs and PLA2s. Moreover, there was considerable variation between antivenoms from different manufacturers. These data indicate that improvements to antivenom manufacturing in India are highly desirable.

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“…lepida , processes involving gene duplication, followed by positive selection, may be responsible for this. This process is one of the most critical mechanisms in venom gene evolution, as documented in snakes, cone snails, spiders, scorpions, and centipedes [ 82 , 114 , 115 , 116 , 117 , 118 , 119 ]. Tandem gene duplication may explain the gene family expansion reported in the genome of Stegodyphus mimosarum spiders, which has 51 Knottin-like toxin genes [ 120 ], and Mesobuthus martensii scorpion, which has more than 100 neurotoxin genes (NaTx, KTx, and ClTx) [ 121 ].…”

Section: Discussionmentioning

confidence: 99%

Identification of Novel Toxin Genes from the Stinging Nettle Caterpillar Parasa lepida (Cramer, 1799): Insights into the Evolution of Lepidoptera Toxins

Mitpuangchon

Nualcharoen

Boonrotpong

et al. 2021

Insects

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Many animal species can produce venom for defense, predation, and competition. The venom usually contains diverse peptide and protein toxins, including neurotoxins, proteolytic enzymes, protease inhibitors, and allergens. Some drugs for cancer, neurological disorders, and analgesics were developed based on animal toxin structures and functions. Several caterpillar species possess venoms that cause varying effects on humans both locally and systemically. However, toxins from only a few species have been investigated, limiting the full understanding of the Lepidoptera toxin diversity and evolution. We used the RNA-seq technique to identify toxin genes from the stinging nettle caterpillar, Parasa lepida (Cramer, 1799). We constructed a transcriptome from caterpillar urticating hairs and reported 34,968 unique transcripts. Using our toxin gene annotation pipeline, we identified 168 candidate toxin genes, including protease inhibitors, proteolytic enzymes, and allergens. The 21 P. lepida novel Knottin-like peptides, which do not show sequence similarity to any known peptide, have predicted 3D structures similar to tarantula, scorpion, and cone snail neurotoxins. We highlighted the importance of convergent evolution in the Lepidoptera toxin evolution and the possible mechanisms. This study opens a new path to understanding the hidden diversity of Lepidoptera toxins, which could be a fruitful source for developing new drugs.

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Mutation, Duplication, and More in the Evolution of Venomous Animals and Their Toxins

Cited by 5 publications

References 66 publications

A Neurotoxic Snake Venom without Phospholipase A2: Proteomics and Cross-Neutralization of the Venom from Senegalese Cobra, Naja senegalensis (Subgenus: Uraeus)

A Neurotoxic Snake Venom without Phospholipase A2: Proteomics and Cross-Neutralization of the Venom from Senegalese Cobra, Naja senegalensis (Subgenus: Uraeus)

Multilevel Comparison of Indian Naja Venoms and Their Cross-Reactivity with Indian Polyvalent Antivenoms

Identification of Novel Toxin Genes from the Stinging Nettle Caterpillar Parasa lepida (Cramer, 1799): Insights into the Evolution of Lepidoptera Toxins

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