Biological characterization of the Amazon coral Micrurus spixii snake venom: Isolation of a new neurotoxic phospholipase A2

Abstract

The Micrurus genus is the American representative of Elapidae family. Micrurus spixii is endemic of South America and northern states of Brazil. Elapidic venoms contain neurotoxins that promote curare-mimetic neuromuscular blockage. In this study, biochemical and functional characterizations of M. spixii crude venom were performed and a new neurotoxic phospholipase A2 called MsPLA2-I was isolated. M. spixii crude venom caused severe swelling in the legs of tested mice and significant release of creatine kinase (CK) showing its myotoxic activity. Leishmanicidal activity against Leishmania amazonensis (IC50 1.24 μg/mL) was also observed, along with antiplasmodial activity against Plasmodium falciparum, which are unprecedented for Micrurus venoms. MsPLA2-I with a Mr 12,809.4 Da was isolated from the crude venom of M. spixii. The N-terminal sequencing of a fragment of 60 amino acids showed 80% similarity with another PLA2 from Micrurus altirostris. This toxin and the crude venom showed phospholipase activity. In a mouse phrenic nerve-diaphragm preparation, M. spixii venom and MsPLA2-I induced the blockage of both direct and indirect twitches. While the venom presented a pronounced myotoxic activity, MsPLA2-I expressed a summation of neurotoxic activity. The results of this study make M. spixii crude venom promising compounds in the exploration of molecules with microbicidal potential.

BmajPLA 2 -II, a basic Lys49-phospholipase A 2 homologue from Bothrops marajoensis snake venom with parasiticidal potential

“…The venom of Viperidae snakes, in general, exhibit more pronounced leishmanicidal activity than that exhibited by B. marajoensis venom [35,70,71]. Both enzymatically inactive and active PLA 2 s from bothropic venoms have shown activity against several species of Leishmania similar to the present study [27][28][29][30]37].…”

“…A value greater than 10 is desired for drugable bioactives [76]. Similar results for antiplasmodial activity were found for PLA 2 s from venoms of other snakes of the Viperidae family, including B. asper, C. d. cumanensis and Micrurus spixii [33][34][35]. Quintana et al [34] showed the ratio of hemolytic activity and antiplasmodial activity by means of an indirect hemolysis test.…”

“…These studies are corroborated by other studies with snake venoms and their PLA 2 s, as well as bee venoms and their PLA 2 s against Plasmodium spp. [33][34][35].…”

Coralsnake Venomics: Analyses of Venom Gland Transcriptomes and Proteomes of Six Brazilian Taxa

“…They concluded that the latter were the most important cause of the neuromuscular blockade. A catalytic phospholipase A 2 from M. s. spixii venom appears to present a similar picture, although there is insufficient information to draw any firm conclusions [182]. Carvalho et al [183] demonstrated that in cultured rat primary hippocampal cells, two PLA 2 s isolated from Micrurus l. lemniscatus venom induced cell death, exhibiting elements of apoptosis, autophagy, and necrosis.…”

Biochemical and functional studies of ColTx-I, a new myotoxic phospholipase A2 isolated from Crotalus oreganus lutosus (Great Basin rattlesnake) snake venom

“…Due to their functional versatility and role in myotoxicity, many studies have researched compounds to aid in the treatment of snakebites to inhibit the toxic effects of PLA 2 , as well as to isolate and characterize new PLA 2 s (Carvalho et al, 2013;Da Silva et al, 2009;Terra et al, 2015). The combination of two chromatographic steps: size exclusion and RP-HPLC, widely used for purification of PLA 2 s (Damico et al, 2005(Damico et al, , 2012Martins et al, 2014), effectively isolated ColTx-I.…”