Getting stoned: Characterisation of the coagulotoxic and neurotoxic effects of reef stonefish (Synanceia verrucosa) venom.

The reef stonefish (Synanceia verrucosa) is a venomous fish which causes excruciatingly painful envenomations. While some research on the pathophysiology and functions of the venom have been conducted, there are still some gaps in the understanding of the venom effects due to the extreme lability of fish venom toxins and the lack of available testing platforms. Here we set out to assess new functions of the venom whilst also attempting to address some unclear pathophysiological effects from previous literature. Utilising a biolayer interferometry assay, our results highlight that the venom binds to the orthosteric site of the α-1 nicotinic acetylcholine receptor as well as the domain IV of voltage-gated Ca2+ (CaV1.2) channel mimotopes. Both these results add some clarity to the previously ambiguous literature. We further assessed the coagulotoxic effects of the venom using thromboelastography and Stago STA-R Max coagulation analyser assays. We reveal that the venom produced anticoagulant activity and significantly delayed time until clot formation of recalcified human plasma which is likely through the degradation of phospholipids. There was a difference between fresh and lyophilised venom activity toward the nicotinic acetylcholine receptor mimotopes and coagulation assays, whilst no difference was observed in the activity toward the domain IV of CaV1.2 mimotopes. This research adds further insights into the neglected area of fish venom whilst also highlighting the extreme labile nature of fish venom toxins.

Is stonefish Synanceia verrucosa envenomation potentially lethal?

Stonefish sting lethality in man has been scarcely documented since the middle of the 20th century. We report three clinical cases, including one fatality, emphasizing the cardiovascular toxicity of the Synanceia verrucosa venom, and its potentially lethal effects. All clinical data have been recently collected in New Caledonia and French Polynesia.

Biochemical and histopathological effects of the stonefish (Synanceia verrucosa) venom in rats.

The Reef Stonefish (Synanceia verrucosa) is one of the most dangerous venomous fish known, and has caused occasional human fatalities. The present study was designed to examine some of the pathological effects of the venom from this fish in Sprague Dawley rats. Crude venom was extracted from venom glands of the dorsal spines of stonefish specimens collected from coral reefs in the Gulf of Aqaba (in the northeastern branch of the Red Sea). The rats were given intramuscular injections of the venom and acute toxicity and effect on selected serum marker enzymes as well as normal architecture of vital organs were evaluated. The rat 24 h LD50 was 38 µg/kg body weight. The serum biochemical markers; alanine transaminase (ALT), lactate dehydrogenase (LDH) and creatine kinase (CK) increased after 6 h of administration of a sub lethal dose of the venom and remained significantly raised at 24 h. Amylase levels also significantly increased after venom injection. The venom caused histological damage manifested as an interstitial hemorrhage, inflammatory cell infiltration, and necrosis. The demonstrated rises in the levels of different critical biochemical parameters in the serum may have led to the observed abnormal morphological changes in these organs. These results may account for some of the clinical manifestations observed in victims of stonefish envenomation. Thus, the presented data provide further in vivo evidence of the stonefish toxic effects that may threaten human life and call for the need for special measures to be considered.

The complete mitochondrial genome of the Synanceia verrucosa (Scorpaeniformes: Synanceiidae).

The complete mitochondrial genome of the Synanceia verrucosa has been sequenced. The mitochondrial genome is 16,506 bp in length, containing 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and one control region. The gene order and the composition of S. verrucosa mitochondrial genome were similar to that of most other vertebrates. The overall nucleotides base composition of the heavy strand is A (31.01%), G (15.06%), C (25.60%), and T (28.34%). With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. The tRNA-Ser2 gene lacked DHC arm and could not fold into a typical clover-leaf secondary structure. Seen from the phylogenetic tree, a stonefish (S. verrucosa), two lionfishes, and eight rockfishes from the same order (Scorpaeniformes) clustered into one branch.