Enhanced activity of an insecticidal protein, trypsin modulating oostatic factor (TMOF), through conjugation with aliphatic polyethylene glycol

Jeffers, Laura A.; Shen, Hongyan; Khalil, Sayed M.S.; Bissinger, Brooke W.; Brandt, Alan E.; Gunnoe, T. Brent; Roe, R. Michael

doi:10.1002/ps.2219

Cited by 10 publications

(11 citation statements)

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“…For example, when the decapeptide trypsin-modulating oostatic factor (TMOF) was PEGlyated, it caused an increase of TMOF toxicity to the mosquito larvae Aedes aegypti and Aedes albopictus (Diptera: Culicidae) and to the lepidopterans neonates of Heliothis virescens and Helicoverpa zea (Lepidoptera: Noctuidae). Furthermore, in H. virescens larvae the conjugated peptide-PEG was accumulated in the insect hemolymph (Jeffers et al 2012). Nachman et al (2012) demonstrated that pyrokinin analogs (multifunctional neuropeptides) conjugated with two PEG polymers promote their biostability when the pea aphid Acyrthosiphon pisum (Homoptera: Aphididae) is fed on a basal diet with the peptide analogs increasing their antifeedant activity.…”

Section: Discussionmentioning

confidence: 98%

Novel nanoinsecticides based on essential oils to control the German cockroach

et al. 2014

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The physicochemical characterization and residual insecticidal activity of poly(ethylene glycol) (PEG) nanoparticles containing essential oils (EOs) from geranium (Geranium sp.) and bergamot (Citrus reticulata L.) were evaluated against Blatella germanica for 1 year. The nanoparticles' size increased during the storage time from \235 to \450 nm; the EO content decreased approximately 50 %, and the abundance of the major components did not show any differences between pre-and post-formulation. The surface characteristics of nanoparticles were analyzed by transmission electronic microscopy. The EO nanoparticles produced a notable increase in the residual contact toxicity apparently because of the slow and persistent release of the active terpenes. In addition, the nanoformulation enhanced the EO contact toxicity. The results indicate that these novel systems could be developed as control agents against German cockroaches.

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Section: Discussionmentioning

confidence: 98%

Novel nanoinsecticides based on essential oils to control the German cockroach

et al. 2014

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“…On the other hand, feeding bollworm larvae on serial doses of TMOF, TMOF‐K and its PEG7 conjugated form “TMOF‐K‐PEG7P” caused inhibition of their food consumption (Jeffers et al . ). Another study, carried out on H. virescens , showed that injection of TMOF into third instars inhibited 50 % of the gut trypsin biosynthesis at a concentration of 0.42 μM (Nauen et al .…”

Section: Discussionmentioning

confidence: 95%

“…The hatched larvae were reared in double distilled H 2 O supplied with traces of standard mosquito food (Jeffers et al . ). The distilled water was replaced on regular bases.…”

Section: Methodsmentioning

confidence: 99%

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Synergistic activity of Bacillus thuringiensis δ‐endotoxin and TMOF against Culex pipiens and Spodoptera littoralis larvae

Mohammed

Diab

Khalil

2017

Entomological Research

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Trypsin Modulating Oostatic Factor (TMOF) is a decapeptide hormone that inhibits the biosynthesis of digestive enzymes in the mosquito midgut. The hormone inhibits food digestion and ultimately leads to starvation and death. It has been used as a biological insecticide to control mosquitoes. In an attempt to increase the insecticidal activity of TMOF, a combination of CryIC (δ‐endotoxin from Bacillus thuringiensis) and TMOF was determined. Eight recombinant proteins fused with GST (glutathione‐S‐transferase) were expressed in Escherichia coli cells. Their insecticidal activities were determined against Culex pipiens and Spodoptera littoralis larvae. Purified GST‐TMOF and its analogue GST‐YDPAS exhibited a moderate toxicity on C. pipiens larvae with LC50 of 145.9 and 339.9 μg/mL, respectively. Unexpectedly, no mortality was observed in first instar larvae of S. littoralis. Puirified GST‐TMOF and GST‐YDPAS together with Bt toxin showed a synergistic toxic effect on both Culex and Spodoptera larvae. In the presence of 100 μg/mL GST‐TMOF and GST‐YDPAS, the median lethal concentration of entomocidus on culex larvae decreased from 52.1 to 16.7 and 31.9 μg/mL, respectively. Likewise, GST‐TMOF and GST‐YDPAS incorporated with 0.07 μg/cm2 of enotmocidus showed insecticidal activity against S. littoralis with LC50 of 16.4 and 21.9 μg/cm2. The E. coli lysates containing GST‐CryIC and its 3′‐truncated version showed low toxicity against the lepidopteran insect (10.8 and 16.6 μg/cm2) compared to 0.15 μg/cm2 of the native crystalline form of CryIC. Similarly, the mosquitocidal activity of the recombinant Bt toxins was low.

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“…TMOF inhibits trypsin biosynthesis and reduces fitness of target insects (Borovsky & Nauen, ). Several methods have been proposed to improve TMOF delivery to hemolymph and insecticidal activity (Shen et al., ; Jeffers et al., ; Kamareddine et al., ). In addition, higher larval mortality was achieved by applying TMOF with other insecticidal proteins, such as toxins of B. thuringiensis (Borovsky et al., ; Misni et al., ; Saiful et al., ) and nucleopolyhedrovirus chitinase A (Fiandra et al., ).…”

Section: Trypsin As a Target Of Pest Controlmentioning

confidence: 99%

Dietary and phylogenetic correlates of digestive trypsin activity in insect pests

Lazarević

Janković-Tomanić

2015

Entomologia Exp Applicata

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Because food proteins are crucial for insect survival, growth, and fecundity, enzymes involved in their digestion have attracted the attention of fundamental entomologists studying the mechanisms and patterns of dietary specialization, and applied entomologists searching for more efficient modes of pest control. Most insects digest proteins using trypsin, an endopeptidase that cleaves polypeptide chains on the carboxyl side of arginine and lysine, two basic amino acids. As the most ancestral proteinase, trypsin is wide-spread in the digestive tract of insects from various orders and with various feeding habits. The present review focuses on biochemical and molecular characteristics, mechanisms of regulation, and adaptive/non-adaptive changes of trypsin activity in response to heterogeneous food environments in a phylogenetic context. Within-and among-species variations in trypsin structure and regulation that contribute to better matching with specific food types are emphasized. We also discuss the relevance of these data for choosing an appropriate strategy for control of insect pests. Pest control strategies to reduce trypsin activity by interfering with substrate binding or trypsin synthesis and secretion have been suggested. Successful application of these procedures requires a multidisciplinary approach and knowledge about digestive physiology of the pest, as well as the structural characteristics of trypsins that determine their interaction with proteinaceous inhibitors and other food compounds, about patterns of developmental changes in trypsin gene expression, adaptive responses of insects to food composition, and various environmental effects on trypsin activity.

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Enhanced activity of an insecticidal protein, trypsin modulating oostatic factor (TMOF), through conjugation with aliphatic polyethylene glycol

Abstract: This research suggests that aliphatic PEG polymers can be used as a new method for increasing the activity of insecticidal proteins.

Cited by 10 publications

References 42 publications

Novel nanoinsecticides based on essential oils to control the German cockroach

Novel nanoinsecticides based on essential oils to control the German cockroach

Synergistic activity of Bacillus thuringiensis δ‐endotoxin and TMOF against Culex pipiens and Spodoptera littoralis larvae

Dietary and phylogenetic correlates of digestive trypsin activity in insect pests

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