Characterization of the Venom of C. d. cumanesis of Colombia: Proteomic Analysis and Antivenomic Study.

The Colombian rattlesnake Crotalus durissus cumanensis is distributed in three geographic zones of the country: the Atlantic Coast, the upper valley of the Magdalena River, and the eastern plains of the Colombian Orinoquía. Its venom induces neurological symptoms, such as eyelid ptosis, myasthenic facies, and paralysis of the respiratory muscles, which can lead to death. Identification and analysis of C. d. cumanensis showed nine groups of proteins responsible for the neurotoxic effect, of which the crotoxin complex was the most abundant (64.71%). Immunorecognition tests of C. d. cumanensis showed that the use of a commercial antivenom manufactured in Mexico resulted in immunoreactivity.

Purification of nasulysin-1: A new toxin from Porthidium nasutum snake venom that specifically induces apoptosis in leukemia cell model through caspase-3 and apoptosis-inducing factor activation.

Nasulysin-1, a new zinc-metalloproteinase from the snake venom of the hognose pit viper Porthidium nasutum, was purified to homogeneity using molecular exclusion chromatography and high performance liquid chromatography on a reverse phase column. The molecular mass of the purified enzyme was 25,900 kDa and pI 4.1, as determined by 1D and 2D polyacrylamide gel electrophoresis. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis of the N-terminal amino acid sequence (1FSPRYIELVVVADHGMFKKYNSNLNTIR28; 1TASLANLEVWSK12; 1DLLPR6) of the purified nasulysin-1, shows close structural homology with other snake venom metalloproteinases isolated from different snake venoms. The purified nasulysin-1 showed specific apoptosis-inducing activity in Jurkat and K562 cells, a T-cell acute lymphocytic leukemia (ALL) and chronic myeloid leukemia (AML) cell model, respectively, without affecting the viability of human lymphocyte cells. After 48 h treatment, nasulysin-1 (20 µg/mL) induced loss of the mitochondrial membrane potential (ΔΨm), activated the apoptosis-inducing factor (AIF), activated the protease caspase-3, and induced chromatin condensation and DNA fragmentation, all hallmarks of apoptosis. These results strongly suggest that nasulysin-1 selectively induces apoptosis to eliminate leukemia cells. Thus, these data warrant further investigation into the use of the metalloproteinase protein, nasulysin-1 as a potential therapeutic agent for treating leukemia.

Cloning and characterization of an antibacterial L-amino acid oxidase from Crotalus durissus cumanensis venom.

An L-amino acid oxidase (LAAO) from Crotalus durissus cumanensis venom (CdcLAAO) was purified to homogeneity using a combination of size-exclusion and ion exchange chromatographies. CdcLAAO is a monomeric protein exhibiting an apparent molecular mass of 55 kDa and a calculated pI of 8. Its complete 498-amino-acid sequence was deduced through cDNA and protein sequencing. The enzyme oxidized L-Leu with K(m) and a V(Max) of 9.23 µM and 0.46 µM/min respectively, and exhibited Kcat and a Kcat/K(m) of 1.8 s(-1) and 195 mM(-1)s(-1). CdcLAAO inhibited in a dose-dependent manner the growth of Staphylococcus aureus and Acinetobacter baumannii. The inhibitory effect was more significant on S. aureus, with a Minimal Inhibitory Concentration (MIC) of 8 µg/mL and Minimal Bactericidal Concentration (MBC) of 16 µg/mL, than against A. baumannii, with a MIC of 16 µg/mL and MBC of 32 µg/mL. However, against Escherichia coli CdcLAAO did not show inhibitory capacity at the concentrations tested (2-128 µg/mL). CdcLAAO did not exhibit cytotoxic activity on the mouse myoblast cell line C(2)C(12) and on peripheral blood mononuclear cell (PBMC).

In vitro antiplasmodial activity of phospholipases A2 and a phospholipase homologue isolated from the venom of the snake Bothrops asper.

The antimicrobial and antiparasite activity of phospholipase A(2) (PLA(2)) from snakes and bees has been extensively explored. We studied the antiplasmodial effect of the whole venom of the snake Bothrops asper and of two fractions purified by ion-exchange chromatography: one containing catalytically-active phospholipases A(2) (PLA(2)) (fraction V) and another containing a PLA(2) homologue devoid of enzymatic activity (fraction VI). The antiplasmodial effect was assessed on in vitro cultures of Plasmodium falciparum. The whole venom of B. asper, as well as its fractions V and VI, were active against the parasite at 0.13 ± 0.01 µg/mL, 1.42 ± 0.56 µg/mL and 22.89 ± 1.22 µg/mL, respectively. Differences in the cytotoxic activity on peripheral blood mononuclear cells between the whole venom and fractions V and VI were observed, fraction V showing higher toxicity than total venom and fraction VI. Regarding toxicity in mice, the whole venom showed the highest lethal effect in comparison to fractions V and VI. These results suggest that B. asper PLA(2) and its homologue have antiplasmodial potential.

An acidic phospholipase A2 with antibacterial activity from Porthidium nasutum snake venom.

Snake venoms are complex mixtures of proteins among which both basic and acidic phospholipases A(2) (PLA(2)s) can be found. Basic PLA(2)s are usually responsible for major toxic effects induced by snake venoms, while acidic PLA(2)s tend to have a lower toxicity. A novel PLA(2), here named PnPLA(2), was purified from the venom of Porthidium nasutum by means of RP-HPLC on a C18 column. PnPLA(2) is an acidic protein with a pI of 4.6, which migrates as a single band under both non-reducing and reducing conditions in SDS-PAGE. PnPLA(2) had a molecular mass of 15,802.6 Da, determined by ESI-MS. Three tryptic peptides of this protein were characterized by HPLC-nESI-MS/MS, and N-terminal sequencing by direct Edman degradation showing homology to other acidic PLA(2)s from viperid venoms. PnPLA(2) displayed indirect hemolytic activity in agarose erythrocyte-egg yolk gels and bactericidal activity against Staphylococcus aureus in a dose-dependent manner, with a MIC and MBC of 32 µg/mL. In addition, PnPLA(2) showed a potent inhibitory effect on platelet aggregation with doses up to 40 µg/mL. This acidic PLA(2), in contrast to basic enzymes isolated from other viperid snake venoms, was not cytotoxic to murine skeletal muscle myoblasts C(2)C(12). This is the first report on a bactericidal protein of Porthidium nasutum venom.