Dataset Information

Evaluation of Chemical Strategies for Improving the Stability and Oral Toxicity of Insecticidal Peptides.

ABSTRACT: Spider venoms are a rich source of insecticidal peptide toxins. Their development as bioinsecticides has, however, been hampered due to concerns about potential lack of stability and oral bioactivity. We therefore systematically evaluated several synthetic strategies to increase the stability and oral potency of the potent insecticidal spider-venom peptide ?-HXTX-Hv1a (Hv1a). Selective chemical replacement of disulfide bridges with diselenide bonds and N- to C-terminal cyclization were anticipated to improve Hv1a resistance to proteolytic digestion, and thereby its activity when delivered orally. We found that native Hv1a is orally active in blowflies, but 91-fold less potent than when administered by injection. Introduction of a single diselenide bond had no effect on the susceptibility to scrambling or the oral activity of Hv1a. N- to C-terminal cyclization of the peptide backbone did not significantly improve the potency of Hv1a when injected into blowflies and it led to a significant decrease in oral activity. We show that this is likely due to a dramatically reduced rate of translocation of cyclic Hv1a across the insect midgut, highlighting the importance of testing bioavailability in addition to toxin stability.

SUBMITTER: Herzig V

PROVIDER: S-EPMC6164231 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Evaluation of Chemical Strategies for Improving the Stability and Oral Toxicity of Insecticidal Peptides.

Herzig Volker V de Araujo Aline Dantas AD Greenwood Kathryn P KP Chin Yanni K-Y YK Windley Monique J MJ Chong Youmie Y Muttenthaler Markus M Mobli Mehdi M Audsley Neil N Nicholson Graham M GM Alewood Paul F PF King Glenn F GF

Biomedicines 20180828 3

Spider venoms are a rich source of insecticidal peptide toxins. Their development as bioinsecticides has, however, been hampered due to concerns about potential lack of stability and oral bioactivity. We therefore systematically evaluated several synthetic strategies to increase the stability and oral potency of the potent insecticidal spider-venom peptide ω-HXTX-Hv1a (Hv1a). Selective chemical replacement of disulfide bridges with diselenide bonds and N- to C-terminal cyclization were anticipat ...[more]

PMID: 30154370

Similar Datasets

Project description:Double-knotted peptides identified in venoms and synthetic bivalent peptide constructs targeting ion channels are emerging tools for the study of ion channel pharmacology and physiology. These highly complex and disulfide-rich peptides contain two individual cystine knots, each comprising six cysteines and three disulfide bonds. Until now, native double-knotted peptides, such as Hi1a and DkTx, have only been isolated from venom or produced recombinantly, whereas engineered double-knotted peptides have successfully been produced through enzymatic ligation using sortase A to form a seamless amide bond at the ligation site between two knotted toxins, and by alkyne/azide click chemistry, joining two peptide knots via a triazole linkage. To further pursue these double-knotted peptides as pharmacological tools or probes for therapeutically relevant ion channels, we sought to identify a robust methodology resulting in a high yield product that lends itself to rapid production and facile mutational studies. In this study, we evaluated the ligation efficiency of enzymatic (sortase A5°, butelase 1, wild-type OaAEP 1, C247A-OaAEP 1, and peptiligase) and mild chemical approaches (α-ketoacid-hydroxylamine, KAHA) for forming a native amide bond linking the toxins while maintaining the native disulfide connectivity of each pre-folded peptide. We used two NaV1.7 inhibitors: PaurTx3, a spider-derived gating modifier peptide, and KIIIA, a small cone snail-derived pore blocker peptide, which have previously been shown to increase affinity and inhibitory potency on hNaV1.7 when ligated together. Correctly folded peptides were successfully ligated in varying yields, without disulfide bond shuffling or reduction, with sortase A5° being the most efficient, resulting in 60% ligation conversion within 15 min. In addition, electrophysiology studies demonstrated that for these two peptides, the amino acid composition of the linker did not affect the activity of the double-knotted peptides. This study demonstrates the powerful application of enzymes in efficiently ligating complex disulfide-rich peptides, paving the way for facile production of double-knotted peptides.

Project description:BackgroundNanomaterials in plant protection promise many benefits over conventional pesticide products. Nano-enabled pesticides may alter the functionality or risk profile of active ingredients. Cationic nanochitin whiskers (NC) possess strong biological activity against wheat aphids. However, toxicity and synergistic effects of NC with chemical pesticides against pest insects has not been systemically reported. This study investigated the insecticidal enhancement by NC with Omethoate (40% EC), Imidacloprid (10% WP), and Acetamiprid (40% WG) for pest control using wheat aphid as piercing-sucking mouthparts insect. Fluorescein isothiocyanate labelled NC was used to monitor the uptake and transportation pathway of NC inside the target insects. Toxicity of NC was tested with Sprague-Dawley (SD) rat. Our findings provide a theoretical basis for future application of NC in plant protection against pest insects.ResultsNCs synthesized by acidic hydrolysis were rod-like nanoparticles in a range of 50-150 nm in length and 30-50 nm in width, which examined by electron microscopy and dynamic light scattering methods. The charge density and zeta potential were about 63 mmol/kg and + 36.4 mV, respectively. By absorption and/or contact action of 30-50 mg/L of NC suspension, the corrected mortality of wheat aphids reached up to 80% or above after 12 h treatment, NC could be distributed through digestive system and relocated from mouth to other tissues inside the insect body. When associated with dilutions of conventional pesticides, the corrected mortality were significantly increased up to 95% or above. The dosage of the chemical pesticide and nanochitin in the mixtures (1:1 by volume) were all reduced to half. The acute oral toxicity Lethal Dose 50% (LD50) to SD rat is greater than 5000 mg/kg BW (body weight) in male and female, acute dermal toxicity LD50 is greater than 2000 mg/kg BW of NC.ConclusionsNC has a strong promotive effect on insecticidal effectiveness of chemical insecticides. It was easily absorbed by plant, transported and distributed from mouth to other tissues of the insects while sucking plant fluid. Low acute oral and dermal toxicity to SD rat indicated that it is safe to apply in agriculture and food industry. NCs has a great potential for water-based nanopesticide formulation to reduce chemical pesticide use for future agro-environmental sustainability.

Dataset Information

Evaluation of Chemical Strategies for Improving the Stability and Oral Toxicity of Insecticidal Peptides.

Publications

Evaluation of Chemical Strategies for Improving the Stability and Oral Toxicity of Insecticidal Peptides.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets