Purification and Characterization of a Novel Insecticidal Toxin, μ-sparatoxin-Hv2, from the Venom of the Spider Heteropoda venatoria

Zhen Xiao; Yunxiao Zhang; Jiao Zeng; Songping Liang; Cheng Tang; Zhonghua Liu

doi:10.3390/toxins10060233

Purification and Characterization of a Novel Insecticidal Toxin, μ-sparatoxin-Hv2, from the Venom of the Spider Heteropoda venatoria

Toxins (Basel). 2018 Jun 7;10(6):233. doi: 10.3390/toxins10060233.

Authors

Zhen Xiao¹, Yunxiao Zhang², Jiao Zeng³, Songping Liang⁴, Cheng Tang⁵, Zhonghua Liu⁶

Affiliations

¹ The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China. Zhen-Xiao@outlook.com.
² The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China. Zhangyx@smail.hunnu.edu.cn.
³ The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China. Jiaozeng_@outlook.com.
⁴ The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China. liangsp@hunnu.edu.cn.
⁵ The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China. chengtang@hunnu.edu.cn.
⁶ The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China. liuzh@hunnu.edu.cn.

Abstract

The venom of the spider Heteropoda venatoria produced lethal effect to cockroaches as reported in our previous study, and could be a resource for naturally-occurring insecticides. The present study characterized a novel cockroach voltage-gated sodium channels (Na_Vs) antagonist, μ-sparatoxin-Hv2 (μ-SPRTX-Hv2 for short), from this venom. μ-SPRTX-Hv2 is composed of 37 amino acids and contains six conserved cysteines. We synthesized the toxin by using the chemical synthesis method. The toxin was lethal to cockroaches when intraperitoneally injected, with a LD₅₀ value of 2.8 nmol/g of body weight. Electrophysiological data showed that the toxin potently blocked Na_Vs in cockroach dorsal unpaired median (DUM) neurons, with an IC₅₀ of 833.7 ± 132.2 nM, but it hardly affected the DUM voltage-gated potassium channels (K_Vs) and the DUM high-voltage-activated calcium channels (HVA Ca_Vs). The toxin also did not affect Na_Vs, HVA Ca_Vs, and Kvs in rat dorsal root ganglion (DRG) neurons, as well as Na_V subtypes Na_V1.3⁻1.5, Na_V1.7, and Na_V1.8. No envenomation symptoms were observed when μ-SPRTX-Hv2 was intraperitoneally injected into mouse at the dose of 7.0 μg/g. In summary, μ-SPRTX-Hv2 is a novel insecticidal toxin from H. venatoria venom. It might exhibit its effect by blocking the insect Na_Vs and is a candidate for developing bioinsecticide.

Keywords: bioinsecticide; spider peptide toxin; voltage-gated sodium channels.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Cells, Cultured
Cockroaches / drug effects
Ganglia, Spinal / drug effects
Ganglia, Spinal / physiology
Insecticides / pharmacology*
Mice, Inbred C57BL
Neurons / drug effects
Neurons / physiology
Rats, Sprague-Dawley
Spider Venoms / chemistry*
Toxins, Biological / genetics
Toxins, Biological / pharmacology*
Voltage-Gated Sodium Channel Blockers / pharmacology*
Voltage-Gated Sodium Channels / physiology*

Substances

Insecticides
Spider Venoms
Toxins, Biological
Voltage-Gated Sodium Channel Blockers
Voltage-Gated Sodium Channels