Displaying publications 1 - 20 of 24 in total

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  1. Tan NH, Ponnudurai G
    PMID: 1360387
    1. The enzymatic, hemorrhagic, procoagulant and anticoagulant activities of venoms of some animals including snakes, lizards, toads, scorpions, spider, wasps, bees and ants were compared. 2. Snake venom was the richest source of enzymes among the animal venoms. Most other animal venoms were devoid of phosphodiesterase, L-amino acid oxidase, alkaline phosphomonoesterase and acetylcholinesterase activities and only a few exhibited arginine ester hydrolase activity. These venoms, however, exhibited wide ranges of protease, 5'-nucleotidase and hyaluronidase activities. Most of the animal venoms examined exhibited some phospholipase A activity. 3. Other than snake venoms, only venoms of the toad Bufo calamita and the lizards were hemorrhagic, and only venoms of the social wasps, social bees and harvester ant exhibited strong anticoagulant activity. Procoagulant activity occurs only in snake venoms.
    Matched MeSH terms: Amphibian Venoms/metabolism; Ant Venoms/metabolism; Bee Venoms/metabolism; Scorpion Venoms/metabolism; Snake Venoms/metabolism; Venoms/metabolism; Wasp Venoms/metabolism
  2. Malih I, Ahmad rusmili MR, Tee TY, Saile R, Ghalim N, Othman I
    J Proteomics, 2014 Jan 16;96:240-52.
    PMID: 24269350 DOI: 10.1016/j.jprot.2013.11.012
    The proteome of the venom of Naja haje legionis, the only medically important elapid species in Morocco, has been elucidated by using a combination of proteomic techniques that includes size exclusion chromatography, reverse-phase HPLC, Tricine/SDS-Page, tryptic digestion, Q-TOF tandem mass spectrometry and database search. The sequence analysis of venom fractions revealed a highly complex venom proteome which counts a total of 76 proteins identified from database that can be assigned into 9 proteins families. We report the identification of: cobra venom factor (CVF), l-amino-acid oxidases (LAAO), acetylcholinesterase (AChE), snake venom metalloproteinases (SVMP), cysteine rich secretory proteins (CRISP), venom nerve growth factor (vNGF), phospholipases A2 (PLA2), vespryns, kunitz-type inhibitor, short neurotoxins, long neurotoxins, weak neurotoxins, neurotoxin like proteins, muscarinic toxins, cardiotoxins and cytotoxins. Comparison of these proteins showed high sequence homology with proteins from other African and Asian cobras. Further works are needed to assess the contribution of individual toxins in venom toxicity.
    Matched MeSH terms: Elapid Venoms/metabolism*
  3. Tan CH, Tan KY, Lim SE, Tan NH
    J Proteomics, 2015 Aug 3;126:121-30.
    PMID: 26047715 DOI: 10.1016/j.jprot.2015.05.035
    The venom proteome of Hydrophis schistosus (syn: Enhydrina schistosa) captured in Malaysian waters was investigated using reverse-phase HPLC, SDS-PAGE and high-resolution liquid chromatography-tandem mass spectrometry. The findings revealed a minimalist profile with only 18 venom proteins. These proteins belong to 5 toxin families: three-finger toxin (3FTx), phospholipase A2 (PLA2), cysteine-rich secretory protein (CRISP), snake venom metalloprotease (SVMP) and L-amino acid oxidase (LAAO). The 3FTxs (3 short neurotoxins and 4 long neurotoxins) constitute 70.5% of total venom protein, 55.8% being short neurotoxins and 14.7% long neurotoxins. The PLA2 family consists of four basic (21.4%) and three acidic (6.1%) isoforms. The minor proteins include one CRISP (1.3%), two SVMPs (0.5%) and one LAAO (0.2%). This is the first report of the presence of long neurotoxins, CRISP and LAAO in H. schistosus venom. The neurotoxins and the basic PLA2 are highly lethal in mice with an intravenous median lethal dose of <0.2 μg/g. Cross-neutralization by heterologous elapid antivenoms (Naja kaouthia monovalent antivenom and Neuro polyvalent antivenom) was moderate against the long neurotoxin and basic PLA2, but weak against the short neurotoxin, indicating that the latter is the limiting factor to be overcome for improving the antivenom cross-neutralization efficacy.
    Matched MeSH terms: Elapid Venoms/metabolism*
  4. Nget Hong Tan, Chon Seng Tan
    Toxicon, 1988;26(11):989-96.
    PMID: 3245058
    The toxic and biological activities of four samples of Trimeresurus purpureomaculatus venom were examined. The lethality, protein composition and biological activities of the four venom samples were similar. Three of the venom samples had LD50 (i.v.) values of 0.9 micrograms/g while the fourth had a lower LD50 (i.v.) of 0.45 micrograms/g. All four venom samples exhibited hemorrhagic, edema-inducing, anticoagulant and thrombin-like activities as well as the usual enzymes found in crotalid venoms. DEAE-Sephacel ion exchange chromatographic fractionation of the venom yielded 10 protein fractions. Only two fractions (fractions A and F) were lethal to mice; the major lethal fraction being fraction F. This fraction had an LD50 (i.v.) of 0.2 micrograms/g and exhibited hemorrhagic, edema-inducing and thrombin-like activity. It also exhibited phospholipase A, arginine ester hydrolase, arginine amidase, protease, 5'-nucleotidase, acetylcholinesterase and alkaline phosphomonoesterase activities. The lethal potency of fraction F is potentiated by fraction G, which exhibited anticoagulant activity as well as hemorrhagic, edema-inducing and enzymatic activities. Fractions F plus G account for almost 100% of the lethal potency of the venom.
    Matched MeSH terms: Crotalid Venoms/metabolism
  5. Tan CH, Tan KY, Tan NH
    Methods Mol Biol, 2019;1871:83-92.
    PMID: 30276733 DOI: 10.1007/978-1-4939-8814-3_5
    Snake venoms are complex mixtures of proteins and peptides that play vital roles in the survival of venomous snakes. As with their diverse pharmacological activities, snake venoms can be highly variable, hence the importance of understanding the compositional details of different snake venoms. However, profiling venom protein mixtures is challenging, in particular when dealing with the diversity of protein subtypes and their abundances. Here we described an optimized strategy combining a protein decomplexation method with in-solution trypsin digestion and mass spectrometry of snake venom proteins. The approach involves the integrated use of C18 reverse-phase high-performance liquid chromatography (RP-HPLC), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and nano-electrospray ionization tandem mass spectrometry (nano-ESI-LC-MS/MS).
    Matched MeSH terms: Snake Venoms/metabolism*
  6. Tan CH, Wong KY, Huang LK, Tan KY, Tan NH, Wu WG
    Toxins (Basel), 2022 Dec 07;14(12).
    PMID: 36548757 DOI: 10.3390/toxins14120860
    Naja nivea (Cape Cobra) is endemic to southern Africa. Envenoming by N. nivea is neurotoxic, resulting in fatal paralysis. Its venom composition, however, has not been studied in depth, and specific antivenoms against it remain limited in supply. Applying a protein decomplexation approach, this study unveiled the venom proteome of N. nivea from South Africa. The major components in the venom are cytotoxins/cardiotoxins (~75.6% of total venom proteins) and alpha-neurotoxins (~7.4%), which belong to the three-finger toxin family. Intriguingly, phospholipase A2 (PLA2) was undetected-this is a unique venom phenotype increasingly recognized in the African cobras of the Uraeus subgenus. The work further showed that VINS African Polyvalent Antivenom (VAPAV) exhibited cross-reactivity toward the venom and immunorecognized its toxin fractions. In mice, VAPAV was moderately efficacious in cross-neutralizing the venom lethality with a potency of 0.51 mg/mL (amount of venom completely neutralized per milliliter of antivenom). In the challenge-rescue model, VAPAV prevented death in 75% of experimentally envenomed mice, with slow recovery from neurotoxicity up to 24 h. The finding suggests the potential para-specific utility of VAPAV for N. nivea envenoming, although a higher dose or repeated administration of the antivenom may be required to fully reverse the neurotoxic effect of the venom.
    Matched MeSH terms: Elapid Venoms/metabolism
  7. Tan CH, Tan KY, Fung SY, Tan NH
    BMC Genomics, 2015;16:687.
    PMID: 26358635 DOI: 10.1186/s12864-015-1828-2
    The king cobra (Ophiophagus hannah) is widely distributed throughout many parts of Asia. This study aims to investigate the complexity of Malaysian Ophiophagus hannah (MOh) venom for a better understanding of king cobra venom variation and its envenoming pathophysiology. The venom gland transcriptome was investigated using the Illumina HiSeq™ platform, while the venom proteome was profiled by 1D-SDS-PAGE-nano-ESI-LCMS/MS.
    Matched MeSH terms: Venoms/metabolism*
  8. Mariam K, Tu AT
    J Nat Toxins, 2002 Dec;11(4):393-8.
    PMID: 12503884
    Sea snake venoms contain less protein than those of land snakes (Toom et al., 1969). Sea snake venoms lack arginine ester hydrolyzing activity, whereas those of Crotalidae and Viperidae have such activity (Tu et al., 1966). Sea snakes live in salty water, and their venoms may be different from those of land snakes. Because of the difficulty in obtaining sea snake venoms, information about sea snake venoms is quite incomplete. NGF is commonly present in the venoms of land snakes such as Elapidae, Viperidae, and Crotalidae (Cohen and Levi-Montalcini, 1956; Lipps, 2002). It is therefore of interest to investigate the presence or absence of NGF in sea snake venoms. In order to investigate the presence or absence of NGF, five sea snake venoms were selected. Lapemis hardwickii (Hardwick's sea snake) and Acalyptophis peronii venom were obtained from the Gulf of Thailand. Hydrophis cyanocinctus (common sea snake) and Enhydrina schistosa (beaked sea snake) venom were obtained from the Strait of Malacca. Laticauda semifasciata (broad band blue sea snake) venom was also examined and the venom was obtained from Gato Island in the Philippines.
    Matched MeSH terms: Elapid Venoms/metabolism*
  9. Tan NH, Arunmozhiarasi A, Ponnudurai G
    PMID: 1685421
    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.
    Matched MeSH terms: Elapid Venoms/metabolism
  10. Tan NH, Ponnudurai G
    PMID: 1981349
    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.
    Matched MeSH terms: Elapid Venoms/metabolism
  11. Lazarev VN, Polina NF, Shkarupeta MM, Kostrjukova ES, Vassilevski AA, Kozlov SA, et al.
    Antimicrob Agents Chemother, 2011 Nov;55(11):5367-9.
    PMID: 21876050 DOI: 10.1128/AAC.00449-11
    Spider venoms are vast natural pharmacopoeias selected by evolution. The venom of the ant spider Lachesana tarabaevi contains a wide variety of antimicrobial peptides. We tested six of them (latarcins 1, 2a, 3a, 4b, 5, and cytoinsectotoxin 1a) for their ability to suppress Chlamydia trachomatis infection. HEK293 cells were transfected with plasmid vectors harboring the genes of the selected peptides. Controlled expression of the transgenes led to a significant decrease of C. trachomatis viability inside the infected cells.
    Matched MeSH terms: Spider Venoms/metabolism*
  12. Tan NH, Ponnudurai G, Chung MC
    Toxicon, 1997 Jun;35(6):979-84.
    PMID: 9241791
    The proteolytic specificity of rhodostoxin, the major hemorrhagin from Calloselasma rhodostoma (Malayan pit viper) venom was investigated using oxidized B-chain of bovine insulin as substrate. Six peptide bonds were cleaved: Ser9-Hist10, His10-Leu11, Ala14-Leu15, Tyr16-Leu17, Gly20-Glu21 and Phe24-Phe25. Deglycosylated rhodostoxin, however, cleaved primarily at Arg22-Gly23.
    Matched MeSH terms: Crotalid Venoms/metabolism*
  13. Tan CH, Tan KY
    Methods Mol Biol, 2019;1871:153-158.
    PMID: 30276739 DOI: 10.1007/978-1-4939-8814-3_11
    Reverse-phase high-performance liquid chromatography is commonly employed as a decomplexing strategy in snake venom proteomics. The chromatographic fractions often contain relatively pure toxins that can be assessed functionally for toxicity level through the determination of their median lethal doses (LD50). Further, antivenom efficacy can be evaluated specifically against these venom fractions to understand the limitation of the antivenom as the treatment for snake envenomation. However, methods of toxicity assessment and antivenom evaluation vary across laboratories; hence there is a need to standardize the protocols and parameters, in particular those related to the neutralizing efficacy of antivenom. This chapter outlines the important in vivo techniques and data interpretation that can be applied in the functional study of snake venom proteomes.
    Matched MeSH terms: Snake Venoms/metabolism*
  14. Tan KY, Liew JL, Tan NH, Quah ESH, Ismail AK, Tan CH
    J Proteomics, 2019 02 10;192:246-257.
    PMID: 30243938 DOI: 10.1016/j.jprot.2018.09.006
    The Asiatic coral snakes are basal in the phylogeny of coral snakes. Although envenoming by the Asiatic coral snakes is rarely fatal, little is known about their venom properties and variability from the American coral snakes. Integrating reverse-phase high performance liquid chromatography and nano-liquid chromatography-tandem mass spectrometry, we showed that the venom proteome of the Malaysian banded or striped coral snake (Calliophis intestinalis) was composed of mainly phospholipases A2 (PLA2, 43.4%) and three-finger toxins (3FTx, 20.1%). Within 3FTx, the cytotoxins or cardiotoxins (CTX) dominated while the neurotoxins' content was much lower. Its subproteomic details contrasted with the 3FTx profile of most Micrurus sp., illustrating a unique dichotomy of venom phenotype between the Old and the New World coral snakes. Calliophis intestinalis venom proteome was correlated with measured enzymatic activities, and in vivo it was myotoxic but non-lethal to mice, frogs and geckos at high doses (5-10 μg/g). The venom contains species-specific toxins with distinct sequences and antigenicity, and the antibodies raised against PLA2 and CTX of other elapids showed poor binding toward its venom antigens. The unique venom proteome of C. intestinalis unveiled a repertoire of novel toxins, and the toxicity test supported the need for post-bite monitoring of myotoxic complication. SIGNIFICANCE: Malaysian banded or striped coral snake (Calliophis intestinalis) has a cytotoxin (CTX)-predominating venom proteome, a characteristic shared by its congener, the Malayan blue coral snake (Calliophis bivirgata). With little neurotoxins (NTX), it illustrates a CTX/NTX dichotomy of venom phenotype between the Old World and the New World coral snakes. The low toxicity of the venom imply that C. intestinalis bite envenoming can be managed via symptomatic relief of the mild to moderate pain with appropriate analgesia. Systemically, the serum creatine kinase level of patients should be monitored serially for potential complication of myotoxicity. The distinct antigenicity of the venom proteins implies that the empirical use of heterologous antivenom is mostly inappropriate and not recommended.
    Matched MeSH terms: Elapid Venoms/metabolism*
  15. Courtney R, Sachlikidis N, Jones R, Seymour J
    PLoS One, 2015;10(5):e0124256.
    PMID: 25970583 DOI: 10.1371/journal.pone.0124256
    Adult Carukia barnesi medusae feed predominantly on larval fish; however, their mode of prey capture seems more complex than previously described. Our findings revealed that during light conditions, this species extends its tentacles and 'twitches' them frequently. This highlights the lure-like nematocyst clusters in the water column, which actively attract larval fish that are consequently stung and consumed. This fishing behavior was not observed during dark conditions, presumably to reduce energy expenditure when they are not luring visually oriented prey. We found that larger medusae have longer tentacles; however, the spacing between the nematocyst clusters is not dependent on size, suggesting that the spacing of the nematocyst clusters is important for prey capture. Additionally, larger specimens twitch their tentacles more frequently than small specimens, which correlate with their recent ontogenetic prey shift from plankton to larval fish. These results indicate that adult medusae of C. barnesi are not opportunistically grazing in the water column, but instead utilize sophisticated prey capture techniques to specifically target larval fish.
    Matched MeSH terms: Cnidarian Venoms/metabolism
  16. Tan NH, Ponnudurai G
    Comp. Biochem. Physiol., B, 1991;99(2):351-4.
    PMID: 1764914
    1. The protease, phosphodiesterase, alkaline phosphomonoesterase, L-amino acid oxidase, acetylcholinesterase, phospholipase A, 5'-nucleotidase, hyaluronidase, arginine ester hydrolase, procoagulant, anticoagulant and hemorrhagic activities of ten samples of venoms from seven taxa of sea snakes were examined. 2. The results show that venoms of sea snakes of both subfamilies of Hydrophiinae and Laticaudinae are characterized by a very low level of enzymatic activities, except phospholipase A activity and, for some species, hyaluronidase activity. 3. Because of the low levels of enzymatic activities and the total lack of procoagulant and hemorrhagic activities, venom biological properties are not useful for the differentiation of species of sea snakes. Nevertheless, the unusually low levels of enzymatic activities of sea snake venoms may be used to distinguish sea snake venoms from other elapid or viperid venoms.
    Matched MeSH terms: Snake Venoms/metabolism*
  17. Tan NH, Ponnudurai G
    Comp. Biochem. Physiol., B, 1990;96(4):683-8.
    PMID: 2171867
    1. The hemorrhagic, procoagulant, anticoagulant, phosphodiesterase, hyaluronidase, alkaline phosphomonoesterase, 5'-nucleotidase, arginine ester hydrolase, phospholipase A, L-amino acid oxidase and protease activities of 26 samples of venoms of 13 taxa of Vipera were determined and the Sephadex G-75 gel filtration patterns for some of the venoms were also examined. 2. The results indicate the presence of certain common characteristics among the venoms, particularly if V. russelli is excluded from the comparison. The results also support the recently proposed reassignment of V. russelli to a separate genus. 3. The data show that information on venom biological properties can be used for differentiation of venoms of many species of Vipera. Particularly useful for this purpose are the protease, phosphodiesterase, phospholipase A and the procoagulant activities and the Sephadex G-75 gel filtration patterns of the venoms.
    Matched MeSH terms: Viper Venoms/metabolism*
  18. Ratanabanangkoon K, Simsiriwong P, Pruksaphon K, Tan KY, Eursakun S, Tan CH, et al.
    Sci Rep, 2017 08 17;7(1):8545.
    PMID: 28819275 DOI: 10.1038/s41598-017-08962-3
    Snake envenomation is an important medical problem. One of the hurdles in antivenom development is the in vivo assay of antivenom potency which is expensive, gives variable results and kills many animals. We report a novel in vitro assay involving the specific binding of the postsynaptic neurotoxins (PSNTs) of elapid snakes with purified Torpedo californica nicotinic acetylcholine receptor (nAChR). The potency of an antivenom is determined by its antibody ability to bind and neutralize the PSNT, thus preventing it from binding to nAChR. The PSNT of Naja kaouthia (NK3) was immobilized on microtiter wells and nAChR was added to bind with it. The in vitro IC50 of N. kaouthia venom that inhibited 50% of nAChR binding to the immobilized NK3 was determined. Varying concentrations of antisera against N. kaouthia were separately pre-incubated with 5xIC50 of N. kaouthia venom. The remaining free NK3 were incubated with nAChR before adding to the NK3 coated plates. The in vitro and in vivo median effective ratio, ER50s of 12 batches of antisera showed correlation (R 2) of 0.9809 (p 
    Matched MeSH terms: Snake Venoms/metabolism
  19. Tan CH, Tan KY
    Toxins (Basel), 2021 02 09;13(2).
    PMID: 33572266 DOI: 10.3390/toxins13020127
    Envenomation resulted from sea snake bite is a highly lethal health hazard in Southeast Asia. Although commonly caused by sea snakes of Hydrophiinae, each species is evolutionarily distinct and thus, unveiling the toxin gene diversity within individual species is important. Applying next-generation sequencing, this study investigated the venom-gland transcriptome of Hydrophis curtus (spine-bellied sea snake) from Penang, West Malaysia. The transcriptome was de novo assembled, followed by gene annotation and sequence analyses. Transcripts with toxin annotation were only 96 in number but highly expressed, constituting 48.18% of total FPKM in the overall transcriptome. Of the 21 toxin families, three-finger toxins (3FTX) were the most abundantly expressed and functionally diverse, followed by phospholipases A2. Lh_FTX001 (short neurotoxin) and Lh_FTX013 (long neurotoxin) were the most dominant 3FTXs expressed, consistent with the pathophysiology of envenomation. Lh_FTX001 and Lh_FTX013 were variable in amino acid compositions and predicted epitopes, while Lh_FTX001 showed high sequence similarity with the short neurotoxin from Hydrophis schistosus, supporting cross-neutralization effect of Sea Snake Antivenom. Other toxins of low gene expression, for example, snake venom metalloproteinases and L-amino acid oxidases not commonly studied in sea snake venom were also identified, enriching the knowledgebase of sea snake toxins for future study.
    Matched MeSH terms: Elapid Venoms/metabolism
  20. Daltry JC, Ponnudurai G, Shin CK, Tan NH, Thorpe RS, Wüster W
    Toxicon, 1996 Jan;34(1):67-79.
    PMID: 8835335
    The Malayan pit viper (Calloselasma rhodostoma) is of major clinical significance both as a leading cause of snakebite and as the source of ancrod (Arvin). Although its venom has been extensively studied, the degree to which venom composition varies between individuals is poorly known. We individually analysed the venoms of over 100 C. rhodostoma using isoelectric focusing. In all populations, females produced an intense band that was absent from all males, and significant ontogenetic variation was detected. Principal components analysis of the banding profiles also revealed strong geographic variation, which was significantly congruent with variation in the biological activities of the venom (phosphodiesterase, alkalinephosphoesterase, L-amino acid oxidase, arginine ester hydrolase, 5'-nucleotidase, thrombin-like enzyme, haemorrhagic activity). Studies of captive-bred snakes indicate that the intraspecific variation in venom is genetically inherited rather than environmentally induced. The intraspecific variation in venom composition and biological activity could be of applied importance to snakebite therapy, both in correct diagnosis of the source of envenomation and in the development of a more effective antivenom. Greater attention should be given to the source of C. rhodostoma venom used in research to ensure reproducibility of results.
    Matched MeSH terms: Viper Venoms/metabolism
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