Journal of Venom Research最新文献

In Iran intramuscular (IM) administration of antivenoms is used for the treatment of human scorpion envenoming of six medically dangerous scorpion species, including Odonthubuthus doriae (O. doriae). The purpose of the current study is to investigate the efficiency of the intramuscular route and the delay of injection on the neutralizing effect of the available polyvalent antivenom. We compared the pharmacokinetics parameters of O. doriae venom and its antivenom. 5µg (131)I-labeled venom and 0.2µl of antivenom were administered via subcutaneous (SC) or IM into rats. Blood samples were taken at various predetermined time intervals during a 24hr period for the venom and a 360min period for the antivenom. The radio-iodination was carried out using the chloramin-T method. The results showed that pharmacokinetic parameters of the venom were T(1/2) = 496.53min; V(d) = 1522ml/kg; Cl = 2.12 ml/kg/min; mean resident residual time (MRT) = 555.77min, and for the antivenom T(1/2) = 902.13min, V(d) = 666.66 ml/kg , Cl = 0.512 ml/kg/min and MRT = 1292min. The total body clearance of the venom is relatively low in agreement with a high mean residence time. Higher AUC and C(max) values for the antivenom as well as its longer residence time indicate that the venom and antivenom are expected to have enough opportunity to interact in the tissue compartments. Over, this study suggests that the intramuscular administration of a single dose of antivenom (2 vials each of 5ml) based on current protocol in Iran is a suitable route for the treatment of envenomation with O. doriae. Prudently, further clinical studies with similar aims need to be carried out to confirm these findings in human victims.

Testing whether venoms may aid in digestion of the prey, eleven snake venoms were compared for the presence of proteases and endopeptidases that function in alkaline pH conditions. In vitro experiments examined the relative protease and endopeptidase activity of the venoms, which involved combining bovine muscle and snake venom in a buffered solution, encased within dialysis tubing. This mixture was then incubated at room temperature (∼20°C) for 24hr, with constant shaking. Bicinchoninic acid (BCA) assay and ninhydrin assay were used to determine peptide and amino acid concentrations. Histological and immunohistochemical investigations using N. kaouthia venom confirmed in vitro findings. Results show that B. arietans venom generated the highest amount of protein/peptides and amino acids in the dialysates, while O. scutellatus, N. ater niger and P. textilis venom did not show any significant protein degradation under alkaline conditions. Histological examination revealed varying degrees of muscle cell damage for each of the venom investigated, and the immunohistochemical study on N. kaouthia venom showed that the venom penetrated the muscle tissue to a significant degree. In vitro assays and histological results indicate that particular venoms may possess the ability to enhance digestion of bovine muscle tissue.

Viperid snakes of the genus Atropoides are distributed in Mexico and Central America and, owing to their size and venom yield, are capable of provoking severe envenomings in humans. This study evaluated, using an 'antivenomics' approach, the ability of a polyspecific (polyvalent) antivenom manufactured in Costa Rica to recognize the proteins of Atropoides mexicanus and A. picadoi venoms, which are not included in the immunization mixture. In addition, the neutralization of lethal, hemorrhagic, myotoxic, coagulant, proteinase and phospholipase A(2) (PLA(2)) activities of these venoms by the antivenom was assessed. The antivenom was highly-effective in immunodepleting many venom components, particularly high molecular mass P-III metalloproteinases (SVMPs), L-amino acid oxidases, and some serine proteinases and P-I SVMPs. In contrast, PLA(2)s, certain serine proteinases and P-I SVMPs, and a C type lectin-like protein were only partially immunodepleted, and two PLA(2) molecules were not depleted at all. The antivenom was able to neutralize all toxic and enzymatic activities tested, although neutralization of lethality by A. nummifer venom was achieved when a challenge dose of 3 LD(50)s of venom was used, but was iffective when 4 LD(50)s were used. These results, and previously obtained evidence on the immunoreactivity of this antivenom towards homologous and heterologous venoms, revealed the low immunogenicity of a number of venom components (PLA(2)s, CRISPs, P-I SVMPs, and some serine proteinases), underscoring the need to search for innovative immunization protocols to improve the immune response to these antigens.

In geographically isolated populations where intensive medical care or serum therapy is not easily accessible snake envenomation is a major cause for concern. The aim of the present study was to test Camellia sinensis extracts, theaflavin and epigallocatechin (two of the main C. sinensis components) against the irreversible neuromuscular blockade induced by Crotalus durissus terrificus venom in mouse phrenic-nerve diaphragm preparations. A quantitative histological study was also performed. The venom (20µg/ml) completely decreased twitch tension after 70min and 5µg/ml venom abolished 50% of twitch amplitude after 60min. C. sinensis extract induced intense facilitatory effect in the preparation activity at 0.2mg/ml and slightly facilitatory effect at 0.05mg/ml. Both 0.05mg/ml C. sinensis extract and 0.05mg/ml commercial theaflavin maintained partial muscular activity in presence of 5µg/ml venom. The histological data confirms that Cs is able to protect the muscle from the myotoxic activity of the venom. Commercial epigallocatechin gallate did not show pre-synaptic nor post-synaptic activities. C. sinensis extract was able to protect the mouse phrenic-nerve diaphragm against the irreversible neuromuscular blockade induced by C. durissus terrificus venom.

Present study shows that non-covalent interaction of kaouthiotoxin (KTX) with their respective pohospholipase A(2) (PLA(2)) from the venom of N. kaouthia displayed marked synergism to exert cytotoxicity without altering the biochemical properties of PLA(2). For example, although NK-PLA(2) or KTX alone did not induce appreciable hemolysis of washed human erythrocytes; however, the hemolytic potency of NK-PLA(2): KTX complex was significantly higher. Identically, selective lysis of virus infected Sf9 and normal Tn insect cells was further enhanced by the cognate NK-PLA(2): KTX complex as compared to individual components of the complex. Gas-chromatographic analysis of fatty acids released from intact erythrocytes by cytotoxic action of individual NK-PLA(2) and NK-PLA(2): KTX complex demonstrated that ratio between saturated fatty acids (SFA) and unsaturated FA (UFA) was increasing with time of hydrolysis of RBC either in the case of NK-PLA(2) or NK-PLA(2)-KTX complex suggesting NK-PLA(2)-KTX complex apparently displayed the more preference for glycerophospholipids with SFAs on the sn-2 position. Therefore, it may be suggested that KTX first destabilize the target cell membrane followed by higher enzymatic activity of PLA(2) on dislocated and disorganized phospholipid bilayers resulting in a significantly higher (p < 0.05) membrane damage by NK-PLA(2)-KTX complex compared to individual components of the complex.

Mouse P19 embryonic carcinoma (EC) cells are pluripotent and can differentiate into a population consisting largely of neurons and glia cells using a concentration of 5x10(-7)M of retinoic acid (RA). Thus, P19 EC cells are a good model system to study events occurring during the critical phases of neuronal differentiation, in vitro. Honey bee venom (BV) consists of mellitin, phospholipase A2, apamin and several other bioactive substances. Previous studies have shown that mellitin and phospholipase A2 - two major components of BV - play an important role in the differentiation of neurons. The purpose of this study was to examine effects of BV and RA on the differentiation of cholinergic neuron in P19 cell line. Preliminary results obtained from morphological examination showed that six days after treatment with 5x10(-7)M RA, P19 cells produced processes, and gradually obtained neuronal phenotype at approximately day-10. All cells then died at day-11. P19 cells treated with 1.3μg/ml BV produced processes on day-6 and neurons appeared in the next four days. They then proceeded to total size until day-10 and produced elongated processes; however, all cells died on day-11. Using BV and RA together had the same effect but more pronounced differentiating results. It can be concluded that applying BV with RA has an additive effect on cell differentiation and proliferation. The presence of acetylcholinesterase (AChE), frequently used as a marker for neuronal differentiation, was also determined and found using DTNB.

Wasp venoms contain a number of pharmacologically active biomolecules, undertaking a wide range of functions necessary for the wasp's survival. We purified and characterized a novel bioactive peptide (vespin) from the venoms of Vespa magnifica (Smith) wasps with unique primary structure. Its amino acid sequence was determined to be CYQRRVAITAGGLKHRLMSSLIIIIIIRINYLRDNSVIILESSY. It has 44 residues including 15 leucines or isoleucines (32%) in the sequence. Vespin showed contractile activity on isolated ileum smooth muscle. The cDNA encoding vespin precursor was cloned from the cDNA library of the venomous glands. The precursor consists of 67 amino acid residues including the predicted signal peptide and mature vespin. A di-basic enzymatic processing site (-KR-) is located between the signal peptide and the mature peptide. Vespin did not show similarity with any known proteins or peptides by BLAST search, suggesting it is a novel bioactive peptide from wasp venoms.