The enzymatic activities of four samples of Malayan cobra venom were investigated. There was significant variation in the contents of L-amino acid oxidase, alkaline phosphomonoesterase, acetylcholinesterase, phospholipase A, 5'-nucleotidase and hyaluronidase. The phosphodiesterase content was, however, constant. Storage of the lyophilized venom powder at 25 degrees C for 1 month did not affect the enzymatic activities. The venom enzymatic activities were generally also stable at 4 degrees C in 0.85% saline solution. After incubation at 37 degrees C for 39 days in 0.85% saline solution, the venom still retained considerable amounts of enzymatic activities. SP-Sephadex C-25 ion-exchange chromatography of the venom showed that the phospholipase A, L-amino acid oxidase, 5'-nucleotidase, phosphodiesterase and alkaline phosphomonoesterase exist in multiple forms.
1. The biological properties of twelve samples of venoms from all four species of Dendroaspis (mamba) were investigated. 2. Dendroaspis venoms generally exhibited very low levels of protease, phosphodiesterase and alkaline phosphomonoesterase; low to moderately low level of 5'-nucleotidase and very high hyaluronidase activities, but were devoid of L-amino acid oxidase, phospholipase A, acetylcholinesterase and arginine ester hydrolase activities. The unusual feature in venom enzyme content can be used to distinguish Dendroaspis venoms from other snake venoms. 3. All Dendroaspis venoms did not exhibit hemorrhagic or procoagulant activity. Some Dendroaspis venoms, however, exhibited strong anticoagulant activity. The intravenous median lethal dose of the venoms ranged from 0.5 microgram/g mouse to 4.2 micrograms/g mouse. 4. Venom biological activities are not very useful for the differentiation of the Dendroaspis species. The four Dendroaspis venoms, however, can be differentiated by their venom SDS-polyacrylamide gel electrophoretic patterns.
1. The hemorrhagic, procoagulant, anticoagulant, protease, phosphodiesterase, alkaline phosphomonoesterase, L-amino acid oxidase, acetylcholinesterase, arginine ester hydrolase, phospholipase A, 5'-nucleotidase and hyaluronidase activities of 39 samples of venoms from 13 species (15 taxa) of Australian elapids were determined and the Sephadex G-75 gel filtration patterns for some of the venoms were also examined. 2. The results indicate that Australian elapid venoms can be divided into two groups: procoagulant Australian venoms (including N. scutatus, N. ater, O. scutellatus, O. microlepidotus, P. porphyriacus, T. carinatus, H. stephensii and P. textilis) and non-procoagulant Australian venoms (including A. superbus, P. colletti, P. australis, P. guttatus and A. antarcticus). 3. The non-procoagulant Australian venoms exhibited biological properties similar to other elapid venoms, while the procoagulant Australian venoms exhibited some properties characteristic of viperid venoms. 4. The data show that information on venom biological properties can be used for differentiation of many species of Australian elapids. 5. Particularly useful for this purpose are the hyaluronidase, alkaline phosphomonoesterase, acetylcholinesterase, and the procoagulant activities and the Sephadex G-75 gel filtration patterns of the venoms.
1. The biological properties of four venom pooled samples from adult taipan (Oxyuranus scutellatus) snakes and one pooled venom sample from six juvenile taipan snakes (11 months old) were compared. 2. The intravenous LD50 (median lethal dose), procoagulant activity and enzymatic activities of the juvenile venom were not significantly different from those of the adult venoms. 3. The juvenile and adult venoms exhibited similar polyacrylamide gel electrophoretic (PAGE) and SDS-PAGE patterns, indicating that they possessed a similar protein composition. 4. The results suggest that there is no significant age-dependency in the biological properties of taipan venom.
1. The intravenous median lethal doses (LD50), protease, phosphodiesterase, alkaline phosphomonoesterase, L-amino acid oxidase, acetylcholinesterase, phospholipase A, 5'-nucleotidase, hyauronidase and anticoagulant activities of fourteen samples of venoms from the four common species of krait (Bungarus caeruleus, Bungarus candidus, Bungarus multicinctus and Bungarus fasciatus) were examined. 2. The results indicate that even though there are individual variations in the biological properties of the krait venoms, interspecific differences in the properties can be used for differentiation of the venoms from the four species of Bungarus. Particularly useful for this purpose are the LD50's and the contents of 5'-nucleotidase and hyaluronidase of the venoms.
Naja sumatrana venom cytotoxin (sumaCTX) is a basic protein which belongs to three-finger toxin family. It has been shown to induce caspase-dependent, mitochondrial-mediated apoptosis in MCF-7 cells at lower concentrations. This study aimed to investigate the alteration of secretome in MCF-7 cells following membrane permeabilization by high concentrations of sumaCTX, using label-free quantitative (LFQ) approach. The degree of membrane permeabilization of sumaCTX was determined by lactate dehydrogenase (LDH) assay and calcein-propidium iodide (PI) assays. LDH and calcein-PI assays revealed time-dependent membrane permeabilization within a narrow concentration range. However, as toxin concentrations increased, prolonged exposure of MCF-7 cells to sumaCTX did not promote the progression of membrane permeabilization. The secretome analyses showed that membrane permeabilization was an event preceding the release of intracellular proteins. Bioinformatics analyses of the LFQ secretome revealed the presence of 105 significantly distinguished proteins involved in metabolism, structural supports, inflammatory responses, and necroptosis in MCF-7 cells treated with 29.8 μg/mL of sumaCTX. Necroptosis was presumably an initial stress response in MCF-7 cells when exposed to high sumaCTX concentration. Collectively, sumaCTX-induced the loss of membrane integrity in a concentration-dependent manner, whereby the cell death pattern of MCF-7 cells transformed from apoptosis to necroptosis with increasing toxin concentrations.
Four homologous single chain phospholipases A2 (Pa-1G, Pa-5, Pa-12C and Pa-15) were tested for neuromuscular effects on chick biventer cervicis and mouse hemidiaphragm nerve-muscle preparations. The four isozymes blocked directly elicited (mouse hemidiaphragm) and indirectly elicited (mouse and chick nerve-muscle preparations) twitch responses in concentrations of 1-30 micrograms/ml. The order of potency seen in both types of preparations was Pa-1G = Pa-5 greater than Pa-12C much greater than Pa-15. All four isozymes caused slow-onset, sustained contractures and reduction of muscle membrane potentials. In the chick preparation, responses to acetylcholine, carbachol and KCl were reduced by exposure to the toxins. It is concluded that the toxins act primarily postsynaptically to depress muscle contractility, perhaps by directly damaging muscle fibres. The order of potency agrees with their phospholipase A2 activity. Pa-1G is unusual because it is an acidic molecule, most toxic phospholipases being basic.