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J. Venom. Anim. Toxins incl. Trop. Dis.
V.19, p.125-130, 2013.
Original paper - ISSN 1678-9199.
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J. Venom. Anim. Toxins incl. Trop. Dis. V.19, p.125-130, 2013. Original paper - ISSN 1678-9199. |
Characteristics of hemolytic activity induced by skin secretions of the frog Kaloula pulchra hainana
1Key Laboratory of Tropic Biological Resources, Minister of Education, College of Marine Science, Hainan University, Haikou, China
2College of Agriculture, Hainan University, 58, Renmin Road, Haikou, Hainan, 570228, China
ABSTRACT
Background
The hemolytic activity of skin secretions obtained by stimulating the frogKaloula pulchra hainana with diethyl ether was tested using human, cattle, rabbit, and chicken erythrocytes. The skin secretions had a significant concentration-dependent hemolytic effect on erythrocytes. The hemolytic activity of the skin secretions was studied in the presence of osmotic protectants (polyethylene glycols and carbohydrates), cations (Mg2+, Ca2+, Ba2+, Cu2+, and K+), or antioxidants (ascorbic acid, reduced glutathione, and cysteine).
Results
Depending on their molecular mass, osmotic protectants effectively inhibited hemolysis. The inhibition of skin hemolysis was observed after treatment with polyethylene glycols (1000, 3400, and 6000 Da). Among divalent cations, only 1 mM Cu2+ markedly inhibited hemolytic activity. Antioxidant compounds slightly reduced the hemolytic activity.
Conclusions
The results suggested that skin secretions of K. pulchra hainana induce a pore-forming mechanism to form pores with a diameter of 1.36-2.0 nm rather than causing oxidative damage to the erythrocyte membrane.
Key words: Amphibian; Skin secretions; Hemolysis; Pore-forming
Financial source This work was supported by the grants from the National Natural Science Foundation (30700128, 30960053), Natural Science Foundation of Hainan Province (312067), and Foundation of Hainan University (hd09xm67qnjj1148).
Abbreviations PEGs: Polyethylene glycols; NAGA: N-acetyl-D-galactosamine; GSH: Reduced glutathione; BSA: Bovine serum albumin; EDTA: Ethylene diamine tetraacetic acid; KPHTI: Kaloula pulchra hainana trypsin inhibitor; PBS: Phosphate-buffered saline; SE: Standard error; SDS-PAGE: Sodium dodecyl sulfate polyacrylamide gel electrophoresis.
Received: January 8, 2013; Accepted: April 11, 2013