Cry46Ab from Bacillus thuringiensis TK-E6 is a new mosquitocidal toxin with aerolysin-type architecture

Tohru Hayakawa, Akira Sakakibara, Sho Ueda, Yoshinao Azuma, Toru Ide, So Takebe

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Cry46Ab is a Cry toxin derived from Bacillus thuringiensis TK-E6. Cry46Ab is not significantly homologous to other mosquitocidal Cry or Cyt toxins and is classified as an aerolysin-type pore-forming toxin based on structural similarity. In this study, the potency of Cry46Ab was assessed for its potential application to mosquito control. A synthetic Cry46Ab gene, cry46Ab-S1, was designed to produce recombinant Cry46Ab as a glutathione-S-transferase fusion in Escherichia coli. Recombinant Cry46Ab showed apparent toxicity to Culex pipiens larvae, with a 50% lethal dose of 1.02 μg/ml. In an artificial lipid bilayer, Cry46Ab activated by trypsin caused typical current transitions between open and closed states, suggesting it functions as a pore-forming toxin similar to other Cry and Cyt toxins. The single-channel conductance was 103.3 ± 4.1 pS in 150 mM KCl. Co-administration of recombinant Cry46Ab with other mosquitocidal Cry toxins, especially the combination of Cry4Aa and Cry46Ab, resulted in significant synergistic toxicity against C. pipiens larvae. Co-administration of multiple toxins exhibiting different modes of action is believed to prevent the onset of resistance in insects. Our data, taken in consideration with the differences in its structure, suggest that Cry46Ab could be useful in not only reducing resistance levels but also improving the insecticidal activity of Bt-based bio-insecticides.

Original languageEnglish
Pages (from-to)100-106
Number of pages7
JournalInsect Biochemistry and Molecular Biology
Volume87
DOIs
Publication statusPublished - Aug 1 2017

Fingerprint

Bacillus thuringiensis
Bacilli
Larva
Toxicity
Mosquito control
toxins
Mosquito Control
Synthetic Genes
Culex
Lipid bilayers
Lethal Dose 50
Lipid Bilayers
Insecticides
Glutathione Transferase
Trypsin
Escherichia coli
Insects
Fusion reactions
Genes
Culex pipiens

Keywords

  • Bacillus thuringiensis TK-E6
  • Cry46Ab
  • Culex pipiens larvae
  • Mosquito control
  • Single-channel analysis
  • Synergistic toxicity

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Insect Science

Cite this

Cry46Ab from Bacillus thuringiensis TK-E6 is a new mosquitocidal toxin with aerolysin-type architecture. / Hayakawa, Tohru; Sakakibara, Akira; Ueda, Sho; Azuma, Yoshinao; Ide, Toru; Takebe, So.

In: Insect Biochemistry and Molecular Biology, Vol. 87, 01.08.2017, p. 100-106.

Research output: Contribution to journalArticle

@article{99771484c3004949b3edfbb76caa45ef,
title = "Cry46Ab from Bacillus thuringiensis TK-E6 is a new mosquitocidal toxin with aerolysin-type architecture",
abstract = "Cry46Ab is a Cry toxin derived from Bacillus thuringiensis TK-E6. Cry46Ab is not significantly homologous to other mosquitocidal Cry or Cyt toxins and is classified as an aerolysin-type pore-forming toxin based on structural similarity. In this study, the potency of Cry46Ab was assessed for its potential application to mosquito control. A synthetic Cry46Ab gene, cry46Ab-S1, was designed to produce recombinant Cry46Ab as a glutathione-S-transferase fusion in Escherichia coli. Recombinant Cry46Ab showed apparent toxicity to Culex pipiens larvae, with a 50{\%} lethal dose of 1.02 μg/ml. In an artificial lipid bilayer, Cry46Ab activated by trypsin caused typical current transitions between open and closed states, suggesting it functions as a pore-forming toxin similar to other Cry and Cyt toxins. The single-channel conductance was 103.3 ± 4.1 pS in 150 mM KCl. Co-administration of recombinant Cry46Ab with other mosquitocidal Cry toxins, especially the combination of Cry4Aa and Cry46Ab, resulted in significant synergistic toxicity against C. pipiens larvae. Co-administration of multiple toxins exhibiting different modes of action is believed to prevent the onset of resistance in insects. Our data, taken in consideration with the differences in its structure, suggest that Cry46Ab could be useful in not only reducing resistance levels but also improving the insecticidal activity of Bt-based bio-insecticides.",
keywords = "Bacillus thuringiensis TK-E6, Cry46Ab, Culex pipiens larvae, Mosquito control, Single-channel analysis, Synergistic toxicity",
author = "Tohru Hayakawa and Akira Sakakibara and Sho Ueda and Yoshinao Azuma and Toru Ide and So Takebe",
year = "2017",
month = "8",
day = "1",
doi = "10.1016/j.ibmb.2017.06.015",
language = "English",
volume = "87",
pages = "100--106",
journal = "Insect Biochemistry and Molecular Biology",
issn = "0965-1748",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - Cry46Ab from Bacillus thuringiensis TK-E6 is a new mosquitocidal toxin with aerolysin-type architecture

AU - Hayakawa, Tohru

AU - Sakakibara, Akira

AU - Ueda, Sho

AU - Azuma, Yoshinao

AU - Ide, Toru

AU - Takebe, So

PY - 2017/8/1

Y1 - 2017/8/1

N2 - Cry46Ab is a Cry toxin derived from Bacillus thuringiensis TK-E6. Cry46Ab is not significantly homologous to other mosquitocidal Cry or Cyt toxins and is classified as an aerolysin-type pore-forming toxin based on structural similarity. In this study, the potency of Cry46Ab was assessed for its potential application to mosquito control. A synthetic Cry46Ab gene, cry46Ab-S1, was designed to produce recombinant Cry46Ab as a glutathione-S-transferase fusion in Escherichia coli. Recombinant Cry46Ab showed apparent toxicity to Culex pipiens larvae, with a 50% lethal dose of 1.02 μg/ml. In an artificial lipid bilayer, Cry46Ab activated by trypsin caused typical current transitions between open and closed states, suggesting it functions as a pore-forming toxin similar to other Cry and Cyt toxins. The single-channel conductance was 103.3 ± 4.1 pS in 150 mM KCl. Co-administration of recombinant Cry46Ab with other mosquitocidal Cry toxins, especially the combination of Cry4Aa and Cry46Ab, resulted in significant synergistic toxicity against C. pipiens larvae. Co-administration of multiple toxins exhibiting different modes of action is believed to prevent the onset of resistance in insects. Our data, taken in consideration with the differences in its structure, suggest that Cry46Ab could be useful in not only reducing resistance levels but also improving the insecticidal activity of Bt-based bio-insecticides.

AB - Cry46Ab is a Cry toxin derived from Bacillus thuringiensis TK-E6. Cry46Ab is not significantly homologous to other mosquitocidal Cry or Cyt toxins and is classified as an aerolysin-type pore-forming toxin based on structural similarity. In this study, the potency of Cry46Ab was assessed for its potential application to mosquito control. A synthetic Cry46Ab gene, cry46Ab-S1, was designed to produce recombinant Cry46Ab as a glutathione-S-transferase fusion in Escherichia coli. Recombinant Cry46Ab showed apparent toxicity to Culex pipiens larvae, with a 50% lethal dose of 1.02 μg/ml. In an artificial lipid bilayer, Cry46Ab activated by trypsin caused typical current transitions between open and closed states, suggesting it functions as a pore-forming toxin similar to other Cry and Cyt toxins. The single-channel conductance was 103.3 ± 4.1 pS in 150 mM KCl. Co-administration of recombinant Cry46Ab with other mosquitocidal Cry toxins, especially the combination of Cry4Aa and Cry46Ab, resulted in significant synergistic toxicity against C. pipiens larvae. Co-administration of multiple toxins exhibiting different modes of action is believed to prevent the onset of resistance in insects. Our data, taken in consideration with the differences in its structure, suggest that Cry46Ab could be useful in not only reducing resistance levels but also improving the insecticidal activity of Bt-based bio-insecticides.

KW - Bacillus thuringiensis TK-E6

KW - Cry46Ab

KW - Culex pipiens larvae

KW - Mosquito control

KW - Single-channel analysis

KW - Synergistic toxicity

UR - http://www.scopus.com/inward/record.url?scp=85021708299&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85021708299&partnerID=8YFLogxK

U2 - 10.1016/j.ibmb.2017.06.015

DO - 10.1016/j.ibmb.2017.06.015

M3 - Article

VL - 87

SP - 100

EP - 106

JO - Insect Biochemistry and Molecular Biology

JF - Insect Biochemistry and Molecular Biology

SN - 0965-1748

ER -