scholarly journals Synthesis and Characterization of Cry2Ab–AVM Bioconjugate: Enhanced Affinity to Binding Proteins and Insecticidal Activity

Toxins ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 497
Author(s):  
Zhi-Zhen Pan ◽  
Lian Xu ◽  
Yi-Shu Zheng ◽  
Li-Yang Niu ◽  
Bo Liu ◽  
...  
Keyword(s):  
Pest Management ◽  
Insecticidal Activity ◽  
Ligand Docking ◽  
Potential Mechanism ◽  
Protein Fragments ◽  
Bt Toxin ◽  
Dissociation Equilibrium ◽  
Bt Toxins ◽  
Lactone Group

Bacillus thuringiensis insecticidal proteins (Bt toxins) have been widely used in crops for agricultural pest management and to reduce the use of chemical insecticides. Here, we have engineered Bt toxin Cry2Ab30 and bioconjugated it with 4”-O-succinyl avermectin (AVM) to synthesize Cry2Ab–AVM bioconjugate. It was found that Cry2Ab–AVM showed higher insecticidal activity against Plutella xylostella, up to 154.4 times compared to Cry2Ab30. The binding results showed that Cry2Ab–AVM binds to the cadherin-like binding protein fragments, the 10th and 11th cadherin repeat domains in the P. xylostella cadherin (PxCR10–11), with a much higher affinity (dissociation equilibrium constant KD = 3.44 nM) than Cry2Ab30 (KD = 28.7 nM). Molecular docking suggested that the macrolide lactone group of Cry2Ab–AVM ligand docking into the PxCR10–11 is a potential mechanism to enhance the binding affinity of Cry2Ab–AVM to PxCR10–11. These findings offer scope for the engineering of Bt toxins by bioconjugation for improved pest management.

scholarly journals Larvicidal Activity against Aedes aegypti and Chemical Characterization of the Inflorescences of Tagetes patula

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Letícia Maria Krzyzaniak ◽  
Tânia Mara Antonelli-Ushirobira ◽  
Gean Panizzon ◽  
Ana Luiza Sereia ◽  
José Roberto Pinto de Souza ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Aedes Aegypti ◽  
Larvicidal Activity ◽  
Insecticidal Activity ◽  
Chemical Characterization ◽  
Reversed Phase ◽  
Acetone Extract ◽  
Tagetes Patula ◽  
Larval Population

The crude acetone extract (CAE) of defatted inflorescences of Tagetes patula was partitioned into five semipurified fractions: n-hexane (HF), dichloromethane (DF), ethyl acetate (EAF), n-butanol (BF), and aqueous (AQF). BF was fractionated by reversed-phase polyamide column chromatography, obtaining 34 subfractions, which were subjected to HSCCC, where patuletin and patulitrin were isolated. CAE and the fractions BF, EAF, DF, and AQF were analyzed by LC-DAD-MS, and patuletin and patulitrin were determined as the major substances in EAF and BF, respectively. BF was also analyzed by HPLC and capillary electrophoresis (CE), and patulitrin was again determined to be the main substance in this fraction. CAE and the semipurified fractions (750, 500, 300, 100, and 50 mg/L) were assayed for larvicidal activity against Aedes aegypti, with mortality rate expressed as percentage. All fractions except AQF showed insecticidal activity after 24 h exposure of larvae to the highest concentration. However, EAF showed the highest activity with more than 50% reduction in larval population at 50 mg/L. The insecticidal activity observed with EAF might have been due to the higher concentration of patuletin present in this fraction.

scholarly journals Insecticidal Activity of Bacteria from Larvae Breeding Site with Natural Larvae Mortality: Screening of Separated Supernatant and Pellet Fractions

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 486 ◽  
Author(s):  
Handi Dahmana ◽  
Didier Raoult ◽  
Florence Fenollar ◽  
Oleg Mediannikov
Keyword(s):  
Biological Control ◽  
Insecticidal Activity ◽  
Breeding Site ◽  
Bacterial Strains ◽  
Activity Prediction ◽  
Pcr Screening ◽  
Breeding Sites ◽  
Insecticide Activity ◽  
New Compounds

Mosquitoes can transmit to humans devastating and deadly pathogens. As many chemical insecticides are banned due to environmental side effects or are of reduced efficacy due to resistance, biological control, including the use of bacterial strains with insecticidal activity, is of increasing interest and importance. The urgent actual need relies on the discovery of new compounds, preferably of a biological nature. Here, we explored the phenomenon of natural larvae mortality in larval breeding sites to identify potential novel compounds that may be used in biological control. From there, we isolated 14 bacterial strains of the phylum Firmicutes, most of the order Bacillales. Cultures were carried out under controlled conditions and were separated on supernatant and pellet fractions. The two fractions and a 1:1 mixture of the two fractions were tested on L3 and early L4 Aedes albopictus. Two concentrations were tested (2 and 6 mg/L). Larvae mortality was recorded at 24, 48 and 72 h and compared to that induced by the commercialized B. thuringiensis subsp. israelensis. Of the 14 strains isolated, 11 were active against the A. albopictus larvae: 10 of the supernatant fractions and one pellet fraction, and mortality increased with the concentration. For the insecticide activity prediction in three strains of the Bacillus cereus complex, PCR screening of the crystal (Cry) and cytolytic (Cyt) protein families characteristic to B. thuringiensis subsp. israelensis was performed. Most of the genes coding for these proteins’ synthesis were not detected. We identified bacterial strains that exhibit higher insecticidal activity compared with a commercial product. Further studies are needed for the characterization of active compounds.

scholarly journals Outdoor trapping and genetical characterization of populations of the webbing clothes moth Tineola bisselliella (Lepidoptera: Tineidae) in the broader area of Berlin

2011 ◽  
Vol 43 (2) ◽  
pp. 129 ◽  
Author(s):  
Bianca Krüger-Carstensen ◽  
Rudy Plarre
Keyword(s):  
Gene Flow ◽  
Pest Management ◽  
Management Strategies ◽  
Seasonal Abundance ◽  
Subspecies Level ◽  
Culture Heritage ◽  
The City ◽  
Species Mobility ◽  
Tineola Bisselliella

Adapted and effective pest management strategies for the protection of irreplaceable culture heritage as well as for the prevention of damages in households and warehouses are based on reliable information about the presence and distribution of the pest organisms. Monitoring the webbing clothes moth <em>Tineola bisselliella </em>at thirteen outdoor stations in the broader area of Berlin give a first idea of their occurrence in an urban area and the hinterlands. The results demonstrate a seasonal abundance in the city and a missing of this species in the countryside. Data suggest a synanthropic occurrence of the webbing clothes moth rather than an invasion from natural reservoires. Possible molecular examinations on the species and subspecies level are presented to analyze the gene flow between populations and give an impression of species mobility as well as pathways of infestation.

Molecular and Morphological characterization of multiple nucleopolyhedrovirus from Mexico and their insecticidal activity against Spodoptera frugiperda (Lepidoptera: Noctuidae)

2019 ◽  
Vol 144 (1-2) ◽  
pp. 123-132
Author(s):  
Magali Ordóñez‐García ◽  
Claudio Rios‐Velasco ◽  
José de Jesús Ornelas‐Paz ◽  
Juan Carlos Bustillos‐Rodríguez ◽  
Carlos Horacio Acosta‐Muñiz ◽  
...  
Keyword(s):  
Insecticidal Activity ◽  
Spodoptera Frugiperda ◽  
Morphological Characterization ◽  
Multiple Nucleopolyhedrovirus ◽  
Lepidoptera Noctuidae

Purification and Characterization of a High-Molecular-Weight Insecticidal Protein Complex Produced by the Entomopathogenic BacteriumPhotorhabdus luminescens

1998 ◽  
Vol 64 (8) ◽  
pp. 3029-3035 ◽  
Author(s):  
David J. Bowen ◽  
Jerald C. Ensign
Keyword(s):  
Molecular Weight ◽  
Insecticidal Activity ◽  
Protein Complex ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Protein Toxin ◽  
The Family ◽  
Toxin Complex

ABSTRACT Photorhabdus luminescens is a gram-negative enteric bacterium that is found in association with entomopathogenic nematodes of the family Heterorhabditidae. The nematodes infect a variety of soil-dwelling insects. Upon entering an insect host, the nematode releases P. luminescens cells from its intestinal tract, and the bacteria quickly establish a lethal septicemia. When grown in peptone broth, in the absence of the nematodes, the bacteria produce a protein toxin complex that is lethal when fed to, or injected into the hemolymph of, Manduca sexta larvae and several other insect species. The toxin purified as a protein complex which has an estimated molecular weight of 1,000,000 and contains no protease, phospholipase, or hemolytic activity and only a trace of lipase activity. The purified toxin possesses insecticidal activity whether injected or given orally. Analyses of the denatured complex by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed it to be composed of several protein subunits ranging in size from 30 to 200 kDa. The complex was further separated by native gel electrophoresis into three components, two of which retained insecticidal activity. The purified native toxin complex was found to be active in nanogram concentrations against insects representing four orders of the classInsecta.

scholarly journals The genetic characterization of fall armyworm populations in Ecuador and its implications to migration and pest management in the northern regions of South America

PLoS ONE ◽  
2020 ◽  
Vol 15 (8) ◽  
pp. e0236759
Author(s):  
Rodney N. Nagoshi ◽  
Ernesto Cañarte ◽  
Bernardo Navarrete ◽  
Jimmy Pico ◽  
Catalina Bravo ◽  
...  
Keyword(s):  
South America ◽  
Pest Management ◽  
Genetic Characterization ◽  
Fall Armyworm ◽  
Northern Regions
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