تصفح Biological & Environmental Sciences حسب المؤلف "Tounsi, Slim"
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Agrotis segetum midgut putative receptor of Bacillus thuringiensis vegetative insecticidal protein Vip3Aa16 differs from that of Cry1Ac toxin
Ben Hamadou-Charfi, Dorra; Boukedi, Hanen; Abdelkefi-Mesrati, Lobna; Tounsi, Slim; Jaoua, Samir ( Elsevier Inc. , 2013 , Article)Considering the fact that Agrotis segetum is one of the most pathogenic insects to vegetables and cereals in the world, particularly in Africa, the mode of action of Vip3Aa16 of Bacillus thuringiensis BUPM95 and Cry1Ac of ... -
Amino acids Y229 and F603 are involved in Bacillus thuringiensis Cry1Ac delta-endotoxin stability and toxicity
Dammak, Mariam; Ali, Mamdouh Ben; Jaoua, Samir; Tounsi, Slim ( Blackwell Publishing , 2012 , Article)Bacillus thuringiensis Cry1Ac toxin shares structurally five conserved blocs with the other δ-endotoxins. To study the role of some amino acids belonging to these regions, two mutations, Y(229) P and F(603) S, were introduced ... -
Characterisation of novel Bacillus thuringiensis isolates against Aedes aegypti (Diptera: Culicidae) and Ceratitis capitata (Diptera:Tephridae)
Elleuch, Jihen; Tounsi, Slim; Ben Hassen, Najeh Belguith; Lacoix, Marie Noel; Chandre, Fabrice; Jaoua, Samir; Zribi Zghal, Raida... more authors ... less authors ( Elsevier Inc. , 2015 , Article)Bacillus thuringiensis is successfully used in pest management strategies as an eco-friendly bioinsecticide. Isolation and identification of new strains with a wide variety of target pests is an ever growing field. In this ... -
Chemical composition and evaluation of antioxidant and antimicrobial activities of Tunisian Thymelaea hirsuta with special reference to its mode of action
Trigui, Mohamed; Ben Hsouna, Anis; Tounsi, Slim; Jaoua, Samir ( Elsevier B.V. , 2013 , Article)In the present study, we evaluated in vitro antimicrobial and antioxidant properties of Thymelaea hirsuta extracts as well as its phytochemical composition. Total phenolic and flavonoid contents were highest in acetone and ... -
Comparative study of Bacillus thuringiensis Cry1Ia and Cry1Aa delta-endotoxins : activation process and toxicity against Prays oleae
Dammak, Mariam; Tounsi, Slim; Rousis, Souad; Jaoua, Samir ( Elsevier Inc. , 2010 , Article)Cry1Ia and Cry1Aa proteins exhibited toxicities against Prays oleae with LC(50) of 189 and 116 ng/cm(2), respectively. The ability to process Cry1Ia11 protoxin by trypsin, chymotrypsin and P. oleae larvae proteases was ... -
Construction of a Bacillus thuringiensis genetically-engineered strain harbouring the secreted Cry1Ia delta-endotoxin in its crystal
Dammak, Mariam; Jaoua, Samir; Tounsi, Slim ( Springer Netherlands , 2011 , Article)Unlike other Bacillus thuringiensis Cry proteins, Cry1 Ia does not form a crystal since it is a secreted delta-endotoxin. We have engineered a Cry1 Iac chimeric protein by substituting the C-terminal part of Cry1 Ia by the ... -
Cry4Ba and Cyt1Aa proteins from Bacillus thuringiensis israelensis: Interactions and Toxicity mechanism against Aedes aegypti
Elleuch, Jihen; Jaoua, Samir; Darriet, Frederic; Chandre, Fabrice; Tounsi, Slim; Zribi Zghal, Raida... more authors ... less authors ( Elsevier Ltd , 2015 , Article)Individual crystal proteins from Bacillus thuringiensis israelensis exhibit variable levels of insecticidal activities against mosquito larvae. In all cases, they are much less active compared to the whole crystal proteins ... -
Evidence of two mechanisms involved in Bacillus thuringiensis israelensis decreased toxicity against mosquito larvae: Genome dynamic and toxins stability
Elleuch, Jihen; Zribi Zghal, Raida; Lacoix, Marie Noel; Chandre, Fabrice; Tounsi, Slim; Jaoua, Samir... more authors ... less authors ( Elsevier GmbH , 2015 , Article)Biopesticides based on Bacillus thuringiensis israelensis are the most used and most successful around the world. This bacterium is characterized by a dynamic genome able to win or lose genetic materials which leads to a ... -
Histopathological effects and determination of the putative receptor of Bacillus thuringiensis Cry1Da toxin in Spodoptera littoralis midgut
Dalel, BenFarhat-Touzri; Saadaoui, Marwa; Abdelkefi-Mesrati, Lobna; Saadaoui, Imen; Azzouz, Hichem; Tounsi, Slim... more authors ... less authors ( Elsevier , 2012 , Article)Bacillus thuringiensis subsp. aizawai strain HD133, known by its effectiveness against Spodoptera species, produces many insecticidal proteins including Cry1Ab, Cry1Ca and Cry1Da. In the present study, the insecticidal ... -
Integration of a Recombinant Chitinase into Bacillus thuringiensis Parasporal Insecticidal Crystal
Driss, Fatma; Rouis, Souad; Azzouz, Hichem; Tounsi, Slim; Zouari, Nabil; Jaoua, Samir... more authors ... less authors ( Springer-Verlag , 2011 , Article)Chitinases have been successfully used in combination with Bacillus thuringiensis delta-endotoxins forming crystals in order to enhance their insecticidal activities. In this context, we opted for promoting the chitinase ... -
Isolation of the Bacillus thuringiensis plasmid carrying Bacthuricin F4 coding genes and evidence of its conjugative transfer
Ben Fguira, Ines; Fourati, Zaineb; Kamoun, Fakher; Tounsi, Slim; Jaoua, Samir ( The Journal of Infection in Developing Countries , 2014 , Article)INTRODUCTION: Conjugation is an excellent natural mode of DNA transfer in vivo between bacteria, particularly when these conjugative elements carry technological traits such as bacteriocin encoding genes. In the present ... -
New Bacillus thuringiensis toxin combinations for biological control of Lepidopteran larvae
Elleuch, Jihen; Zribi Zghal, Raida; Jemaa, Mohamed; Azzouz, Hichem; Tounsi, Slim; Jaoua, Samir... more authors ... less authors ( Elsevier B.V. , 2014 , Article)Cyt1Aa from Bacillus thuringiensis israelensis is known by its synergistical activity with B. thuringiensis and Bacillus sphaericus toxins. It is able to improve dipteran specific toxins activity and can prevent or overcome ... -
Potential of Photorhabdus temperata K122 bioinsecticide in protecting wheat flour against Ephestia kuehniella
Jallouli, Wafa; Abdelkefi-Mesrati, Lobna; Tounsi, Slim; Jaoua, Samir; Zouari, Nabil ( Elsevier Ltd , 2013 , Article)The present study reports investigations on the insecticidal activity of the entomopathogenic bacterium Photorhabdus temperata K122 against the Mediterranean flour moth Ephestia kuehniella. Cultured in the optimized medium, ... -
Relationship between plasmid loss and gene expression in Bacillus thuringiensis
Driss, Fatma; Tounsi, Slim; Jaoua, Samir ( Springer-Verlag , 2011 , Article)The large genome of Bacillus thuringiensis was shortened by provoking plasmid loss, and the effect of such loss on the expression of both chromosomal and plasmid-harboured genes was studied. It was evidenced that the genomic ... -
Study of the Bacillus thuringiensis Vip3Aa16 histopathological effects and determination of its putative binding proteins in the midgut of Spodoptera littoralis
Abdelkefi-Mesrati, Lobna; Boukedi, Hanen; Dammak-Karray, Mariam; Sellami-Boudawara, Tahya; Jaoua, Samir; Tounsi, Slim... more authors ... less authors ( Elsevier Inc. , 2011 , Article)The bacterium Bacillus thuringiensis produces, at the vegetative stage of its growth, Vip3A proteins with activity against a broad spectrum of lepidopteran insects. The Egyptian cotton leaf worm (Spodoptera littoralis) is ... -
Susceptibility of Agrotis segetum (noctuidae) to Bacillus thuringiensis and analysis of midgut proteinases
Ben Hamadou-Charfi, Dorra; Sauer, Annette Juliane; Abdelkefi-Mesrati, Lobna; Tounsi, Slim; Jaoua, Samir; Stephan, Dietrich... more authors ... less authors ( Taylor & Francis , 2015 , Article)Seventy-eight Bacillus thuringiensis isolates were selected for a screening against the Lepidoptera species Agrotis segetum to search the higher insecticidal activity. In a preliminary bioassay, the spore-crystal mixture ... -
Synthesis of silver nanoparticles using Bacillus velezensis M3-7 lipopeptides: Enhanced antifungal activity and potential use as a biocontrol agent against Fusarium crown rot disease of wheat seedlings
Msmoudi, Fatma; Pothuvattil, Nandagopal S.; Tounsi, Slim; Saadaoui, Imen; Trigui, Mohamed ( Elsevier , 2023 , Article)Bacillus velezensis M3-7 is a hyperactive mutant, 12-fold improved in its antifungal activity, obtained during a previous study from the wild strain BLB371 after a combination of random mutagenesis and medium component ... -
Towards novel Cry toxins with enhanced toxicity/broader: a new chimeric Cry4Ba / Cry1Ac toxin
Zghal, Raida Zribi; Elleuch, Jihen; Ali, Mamdouh Ben; Darriet, Frederic; Rebaï, Ahmed; Chandre, Fabrice; Jaoua, Samir; Tounsi, Slim... more authors ... less authors ( Springer-Verlag , 2017 , Article)Attempts have been made to express or to merge different Cry proteins in order to enhance toxic effects against various insects. Cry1A proteins of Bacillus thuringiensis form a typical bipyramidal parasporal crystal and ... -
Toxin stability improvement and toxicity increase against dipteran and lepidopteran larvae of Bacillus thuringiensis crystal protein Cry2Aa
Elleuch, Jihen; Jaoua, Samir; Ginibre, Carole; Chandre, Fabrice; Tounsi, Slim; Zghal, Raida Z.... more authors ... less authors ( Wiley , 2016 , Article)BACKGROUND Bacillus thuringiensis δ-endotoxins are the most widely used biopesticides for controlling economically important crop pests and disease vectors. Improving their efficacy is of great benefit. Here, an improvement ...