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Revision as of 12:57, 2 October 2024


BmK IT1

Description

BmK IT1 produces a scorpion toxin that acts as a neurotoxin, and it is a type of toxin that is selectively active on lepidopterous and dipterous insects. Due to its high insect toxicity and its selectivity for only lepidopterous and dipterous insects, scorpion toxins can be applied as potential biological insecticides in pest control. [1]


Usage and Biology

Scorpion toxin can be separated into two major categories, excitatory and inhibitory; BmK IT1, the toxin we selected, is an excitatory insect toxin that affects the nervous system of insects by causing an instantaneous contraction paralysis and an increased peak sodium current and a voltage-dependent slowing of sodium current inactivation. Due to its high insect toxicity and its selectivity for only lepidopterous and dipterous insects, scorpion toxins can be applied as potential biological insecticides in pest control.[2][3]

Plasmid construct

Fig 1. Plasmid construct design in pET-28a

Characterization

Fig 2. Western blot analysis was performed to detect His-tagged proteins.

Lane 1: pET-28a-Xpp81Aa1 without IPTG; Lane 2: E. coli BL21 (DE3) cells with pET-28a-Xpp81Aa1 incubated with 1mM IPTG; Lane 3: pET-28a-Cyt2Ba without IPTG; Lane 4: pET-28a-Cyt2Ba incubated with 1mM IPTG; Lane 5: pET-28a-Bmk without IPTG; Lane 6: pET-28a-Bmk with 1mM IPTG

Larvicidal Assay

The larvicidal efficacy of BmK IT1 against Aedes albopictus larvae was tested by exposing 10 larvae in a cup to BmK IT1 by dissolving its pellets collected and dried into powder form. (Pellets containing recombinant biolarvicidal toxins were collected from BL21(DE3) bacterial cultures.) The larvicidal efficacy of toxins was compared with ddH2O as a control. (Note: control larvae were still alive when collected, whereas larvae exposed to larvicides were collected when they died.) The LC50 (lethal concentration required to kill 50% of the population) of larvae was examined and analyzed.

Fig 3. Larvicidal mortality of Aedes albopictus larvae exposed to BmK IT1 collected under IPTG induction for 37°C overnight.

The LC50 was calculated to be 179 mg/mL.

Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    COMPATIBLE WITH RFC[1000]


Reference

[1] Gu, J.-B., Dong, Y.-Q., Peng, H.-J., & Chen, X.-G. (2010). A Recombinant AeDNA Containing the Insect-Specific Toxin, BmK IT1, Displayed an Increasing Pathogenicity on Aedes albopictus. American Journal of Tropical Medicine and Hygiene, 83(3), 614–623. https://doi.org/10.4269/ajtmh.2010.10-0074

[2] Deng, S.-Q., Deng, M.-Z., Chen, J.-T., Zheng, L.-L., & Peng, H.-J. (2017). [Larvicidal activity of recombinant Escherichia coli expressing scorpion neurotoxin AaIT or B.t.i toxin Cyt2Ba against mosquito larvae and formulations for enhancing the effects]. Nan Fang Yi Ke Da Xue Xue Bao = Journal of Southern Medical University, 37(6). https://doi.org/10.3969/j.issn.1673-4254.2017.06.06

[3] Bougis, P. E., Kopeyan, C., Li, H. M., Luo, M. J., Xiong, Y. M., Barton, K. A., & Eitan, M. (1999, January 6). The cdna sequence of an excitatory insect selective neurotoxin from the scorpion buthus martensi karsch. Toxicon. https://www.sciencedirect.com/science/article/abs/pii/S0041010198001767