Purification and antibacterial activities of an L-amino acid oxidase from king cobra (Ophiophagus hannah) venom

Some constituents of snake venom have been found to display a variety of biological activities. The antibacterial property of snake venom, in particular, has gathered increasing scientific interest due to antibiotic resistance. In the present study, king cobra venom was screened against three strains of Staphylococcus aureus [including methicillin-resistant Staphylococcus aureus (MRSA)], three other species of gram-positive bacteria and six gram-negative bacteria. King cobra venom was active against all the 12 bacteria tested, and was most effective against Staphylococcus spp. (S. aureus and S. epidermidis). Subsequently, an antibacterial protein from king cobra venom was purified by gel filtration, anion exchange and heparin chromatography. Mass spectrometry analysis confirmed that the protein was king cobra L-amino acid oxidase (Oh-LAAO). SDS-PAGE showed that the protein has an estimated molecular weight of 68 kDa and 70 kDa under reducing and non-reducing conditions, respectively. The minimum inhibitory concentrations (MIC) of Oh-LAAO for all the 12 bacteria were obtained using radial diffusion assay method. Oh-LAAO had the lowest MIC value of 7.5 µg/mL against S. aureus ATCC 25923 and ATCC 29213, MRSA ATCC 43300, and S. epidermidis ATCC 12228. Therefore, the LAAO enzyme from king cobra venom may be useful as an antimicrobial agent.(AU)

Cytotoxicity of Southeast Asian snake venoms

Cytotoxicity of venoms from eleven medically important snakes found in Southeast Asia (Naja kaouthia, Naja siamensis, Naja sumatrana, Ophiophagus hannah, Bungarus candidus, Bungarus fasciatus, Enhydrina schistosa, Calloselasma rhodostoma, Trimeresurus purpureomaculatus and Tropidolaemus sumatranus) was determined, based on the MTS cytotoxicity assay, which determines the survival of viable cells in monolayer MDCK and Vero cell cultures upon exposure to the snake venoms. Snake venom toxicity was expressed as the venom dose that killed 50% of the cells (CTC50) under the assay conditions. Venoms of C. rhodostoma (2.6 µg/mL, 1.4 µg/mL) and O. hannah were the most cytotoxic (3.8 µg/mL, 1.7 µg/mL) whereas N. siamensis venom showed the least cytotoxicity (51.9 µg/mL, 45.7 µg/mL) against Vero and MDCK cells, respectively. All the viper venoms showed higher cytotoxic potency towards both Vero and MDCK cell lines, in comparison to krait and cobra venoms. E. schistosa did not cause cytotoxicity towards MDCK or Vero cells at the tested concentrations. The cytotoxicity correlates well with the known differences in the composition of venoms from cobras, kraits, vipers and sea snakes.(AU)

Efficacy of tannins from Mimosa pudica and tannic acid in neutralizing cobra (Naja kaouthia) venom

In the present study, the effectiveness of Mimosa pudica tannins (MPT) in neutralizing the lethality of Naja kaouthia venom was compared with commercially derived tannins. Preincubation of MPT with N. kaouthia venom maintained 100 percent survival of mice after 24 hours. The mouse group in which there was no preincubation, no protection against the effects of the venom was observed. M. pudica tannin was found to be more effective in neutralizing the lethality of N. kaouthia venom when compared to commercial tannic acid. Two protein spots were missing in the two-dimensional gel electrophoresis (2-DE) of the MPT treated mouse indicating the down-regulation of venom proteins. The results from this study indicated that tannins obtained from M. pudica are better than tannic acid in neutralizing the lethality of N. kaouthia venom in vitro. However, further investigations are required to establish that M. pudica has potential for treating N. kaouthia snakebites.(AU)

Protein profile analysis of Malaysian snake venoms by two-dimensional gel electrophoresis

Snake venoms comprise a highly complex mixture of proteins, which requires for their characterization the use of versatile two-dimensional electrophoresis techniques. In the present study, venoms obtained from eight snakes (Ophiophagus hannah, Naja kaouthia, Naja sumatrana, Bungarus fasciatus, Trimeresurus sumatranus, Tropidolaemus wagleri, Enhydrina schistosa and Calloselasma rhodostoma) commonly found in Malaysia were separated based on two independent properties, isoelectric point (pI) and molecular weight (MW). Many differences in snake venoms at the inter-family, inter-subfamily, inter-genus and inter-species levels were revealed. Notably, proteins from individuals of the Viperidae family – Trimeresurus sumatranus, Tropidolaemus wagleri and Calloselasma rhodostoma – were found to be numerous and scattered by the two-dimensional gel electrophoresis (2DE) specifically in regions between 37 and 100 kDa compared to the Elapidae venom proteins. The latter were clustered at the basic and lower molecular mass region (less than 20 kDa). Trains of spots were commonly observed, indicating that these proteins may be derived from post-translational modifications. Ophiophagus hannah (Elapidae) revealed a great amount of protein spots in the higher molecular mass range when compared to Enhydrina schistosa, Naja kaouthia, Naja sumatrana and Bungarus fasciatus. Overall 2DE showed large differences in the venom profile of each species, which might be employed as an ancillary tool to the identification of venomous snake species.

Protein profile analysis of Malaysian snake venoms by two-dimensional gel electrophoresis

Snake venoms comprise a highly complex mixture of proteins, which requires for their characterization the use of versatile two-dimensional electrophoresis techniques. In the present study, venoms obtained from eight snakes (Ophiophagus hannah, Naja kaouthia, Naja sumatrana, Bungarus fasciatus, Trimeresurus sumatranus, Tropidolaemus wagleri, Enhydrina schistosa and Calloselasma rhodostoma) commonly found in Malaysia were separated based on two independent properties, isoelectric point (pI) and molecular weight (MW). Many differences in snake venoms at the inter-family, inter-subfamily, inter-genus and inter-species levels were revealed. Notably, proteins from individuals of the Viperidae family - Trimeresurus sumatranus, Tropidolaemus wagleri and Calloselasma rhodostoma - were found to be numerous and scattered by the two-dimensional gel electrophoresis (2DE) specifically in regions between 37 and 100 kDa compared to the Elapidae venom proteins. The latter were clustered at the basic and lower molecular mass region (less than 20 kDa). Trains of spots were commonly observed, indicating that these proteins may be derived from post-translational modifications. Ophiophagus hannah (Elapidae) revealed a great amount of protein spots in the higher molecular mass range when compared to Enhydrina schistosa, Naja kaouthia, Naja sumatrana and Bungarus fasciatus. Overall 2DE showed large differences in the venom profile of each species, which might be employed as an ancillary tool to the identification of venomous snake species.(AU)

Studies on animal schistosomes in Peninsular Malaysia: record of naturally infected animals and additional hosts of Schistosoma spindale.

Surveillance studies on cercarial dermatitis were carried out in paddy growing areas in Peninsular Malaysia. It was observed that dermatitis in paddy planters occurred in paddy fields which were cultivated using animals such as bafflos or fields where domestic animals were allowed to graze during the off planting season as these animals harbored the parasite. The causative agent of cercarial dermatitis was Schistosoma spindale. A total of 215 small mammals trapped from Alor Setar and 126 trapped from Labu were examined for the schistosome. In Alor Setar Bandicota indica, Rattus argentiventer and Rattus rattus diardii were the only wild mammals found to be infected with the parasite, while in the Labu areas only Rattus tiomanicus jalorensis was positive for the schistosome. The occurrence of S. spindale in R. argentiventer and R.r. diardii in Alor Setar and in R.t. jalorensis in Labu constitute new host and geographic distribution records of the schistosome.

Detection of Angiostrongylus malaysiensis circulating antigen using monoclonal antibody-based enzyme-linked immunosorbent assay (MAb-ELISA).

Three MAbs 1C4.2D8, 1C4.2C4 and 1C4.1F5 were produced using sonicated adult worm antigens of Angiostrongylus malaysiensis and they were found to be secreters of IgG1. The MAbs 1C4.2C4 and 1C4.2D8 were found to react with antigens of A. malaysiensis and cross-react with the closely related A. cantonensis but not with other helminths. A total of 108 human sera collected from Orang Asli (aborigenes) from Grik, in the State of Perak were tested for A. malaysiensis infection using the MAb-ELISA. MAb 1C4.1F5 and 25 (23%) were positive. Twenty of these positive samples were tested with the MAb 1C4.2D8 and none was found to be positive.

Spargana infection of frogs in Malaysia.

Frogs caught from two States (Selangor and Langkawi) in Malaysia were examined for spargana of Spirometra sp. Infected frogs usually show no marks of infection but some had swelling and bleeding at the infection site. The size and weight of the infected frogs did not correlate with the infection status. The infection status in relation to human health is discussed.

Humoral and cell mediated immune responses against Schistosoma spindale in BALB/c mice.

(BALB/c mice were infected with cercariae of Schistosoma spindale by tail immersion technique and by dropping some cercariae from a pipet onto the outer surface of the pinna of the ears. Groups of mice were removed on Days 10, 20 and 30 and tested for humoral and cell mediated immune responses using either adult worm or cercarial antigen. On Day 50 the mice were sacrificed and the worm burden was determined for each mouse. This method resulted in an infectivity rate of 89.7%. There was a significant increase in antibody titer to the adult worm antigen while no significant increase was observed for cercarial antigen over the period of the study. Results obtained for cell mediated immunity were more dramatic. There was a significant increase in foot pad swelling for adult worm antigen compared to a significant decrease for cercarial antigen during the course of the infection.

Epidemiology and control of malaria in Malaysia.

In spite of more than 30 years of control activities, malaria continues to be the most important parasitic infection in Malaysia, accounting for 39,189 confirmed cases in 1991, giving an annual parasite incidence rate of 2.2 per 1,000 population. Some factors contributing to the continued transmission of malaria are the development of drug resistant Plasmodium falciparum, changes in vector behavior, and ecological changes due to socio-economic reasons. Malaria parasite rates are higher among the Aborigines, land scheme settlers and those in intimate contact with the jungle, like loggers. There has been no substantial change in the proportion of the three common malaria species responsible for infections, P. falciparum, P. vivax, P. malariae and mixed infections accounting for about 70%, 28%, 1% and 1%, respectively of all infections. Drug resistant P. falciparum is unevenly distributed in Malaysia, but based on clinical experience and in vitro drug sensitivity studies, chloroquine resistance is frequently encountered. There has been clinical and laboratory evidence of resistance to sulfadoxine/pyrimethamine combination as well as quinine, but all these have so far been successfully treated with a combination of quinine and tetracycline. The eradication of the disease is impossible in the near future but there is confidence that with better surveillance techniques and the use of alternative control measures like permethrin impregnated bed-nets to complement existing ones, the target of bringing down the annual parasite incidence to 2 per 1,000 population during the Sixth Malaysian Plan period (1991-1995) can be achieved.

Humoral immune response of Balb/c mice to larval and adult worm antigens of Angiostrongylus malaysiensis.

The development of Angiostrongylus malaysiensis in Balb/c mice and the humoral response due to it were studied by using the enzyme-linked immunosorbent assay (ELISA) with adult worm and L3 antigens. The worms recovered from mice were seen in the brain tissue only, they failed to migrate to the lung as in the normal host (rats). The antibody titres of sera from infected mice, showed similar patterns in response to L3 antigen and to adult worm antigen. However, the highest antibody response could be detected by L3 antigen in the early period after infection while the adult worm antigen detected a higher response in the later stages of development.