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Raida Zribi Zghal, Kais Ghedira, Jihen Elleuch, Marwa Kharrat, Slim Tounsi
BLB406 is a novel isolate of Bacillus thuringiensis with a larvicidal activity against Aedes aegypti larvae. It displays original plasmidic and crystal protein patterns. The present work reported molecular and bioinformatic analyses for the genome sequence of BLB406 using MiSeq Illumina next-generation sequencing technology. The reads were assembled by Velvet tool. Using RAST program and PGAAP the genome of BLB406 strain was shown to contain 6297 genes corresponding to 5924 protein coding sequences. The BLB406 genome investigation with BtToxin_scanner program shows that this strain has an original and different combination of toxins compared to the published ones: five cry genes (cry11, cry22, cry2, cry60, cry64) and two distinct vegetative insecticidal vip4 genes...
May 17, 2018: International Journal of Biological Macromolecules
Showkat A Lone, Abdul Malik, Jasdeep C Padaria
In this study, we present the selection and the characterization of Bacillus thuringiensis (Bt) strains with respect to their cry/cyt gene content and toxicity evaluation toward one of the most important polyphagous lepidopteran pest, Helicoverpa armigera. Fifty-six Bt isolates were obtained from 10 different regions of northwestern Himalayas, recording a total B. thuringiensis index of 0.62. Scanning electron microscopy revealed presence of bipyramidal, spherical, flat and irregular crystal shapes; SDS-PAGE analysis of spore-crystal mixtures showed the prominence of 130, 70, and 100 kDa protein bands in majority of the isolates; PCR analysis with primers for eight cry and cyt gene families and 13 cry gene subfamilies resulted in isolates showing different combinations of insecticidal genes...
December 2017: MicrobiologyOpen
Talaat A El-Kersh, Ashraf M Ahmed, Yazeed A Al-Sheikh, Frédéric Tripet, Mohamed S Ibrahim, Ali A M Metwalli
BACKGROUND: Worldwide, mosquito vectors are transmitting several etiological agents of important human diseases, including malaria, causing millions of deaths every year. In Saudi Arabia, as elsewhere, vector-control is based mostly on chemical insecticides which may be toxic and cause environmental deprivation. Here, to support the development of bio-pesticide alternatives, a study was conducted to identify native Bacillus thuringiensis (Bt) isolates with improved toxicity against the malaria vector, Anopheles gambiae (s...
December 19, 2016: Parasites & Vectors
J Zorzetti, A P S Ricietto, F A P Fazion, A M Meneguim, P M O J Neves, L A Vilas-Boas, R B Rodrigues, G T Vilas-Bôas
The citrus fruit borer, Ecdytolopha aurantiana (Lima, 1927) (Lepidoptera: Tortricidae), is responsible for major losses to the citrus industry because it causes rot and drop of fruits. The current study aimed to select and characterize Bacillus thuringiensis (Berliner, 1911) strains toxic to E. aurantiana. For this purpose, 47 B. thuringiensis strains were evaluated in selective bioassays using first instar larvae of E. aurantiana. The lethal concentration (LC50 ) of the most toxic strains was estimated, and the strains were characterized by morphological, biochemical, and molecular methods...
February 2017: Neotropical Entomology
Margot Paris, Sebastien Marcombe, Eric Coissac, Vincent Corbel, Jean-Philippe David, Laurence Després
Mosquito control is often the main method used to reduce mosquito-transmitted diseases. In order to investigate the genetic basis of resistance to the bio-insecticide Bacillus thuringiensis subsp. israelensis (Bti), we used information on polymorphism obtained from cDNA tag sequences from pooled larvae of laboratory Bti-resistant and susceptible Aedes aegypti mosquito strains to identify and analyse 1520 single nucleotide polymorphisms (SNPs). Of the 372 SNPs tested, 99.2% were validated using DNA Illumina GoldenGate® array, with a strong correlation between the allelic frequencies inferred from the pooled and individual data (r = 0...
November 2013: Evolutionary Applications
Gretel Mendoza, Amelia Portillo, Efraín Arias, Rosa M Ribas, Jorge Olmos
Twenty eight Bacillus thuringiensis strains isolated from the Tijuana-Ensenada region of northwestern Mexico were analyzed to determine the distribution of cry and cyt genes. Crystal production by the strains was examined by scanning electron microscopy, which showed the predominance of cubic crystals. Alkaline-dissolved and trypsin activated crystals were also analyzed by SDS-PAGE, yielding bands of 40-200 kDa. The cry1 and cry2 genes were molecularly characterized using general and newly designed specific primers in addition to other oligonucleotides (cry3, cry4, cry8, cry9, cry11, Nem, cry25, cry29 and cyt), resulting in the identification of novel gene combinations...
December 2012: International Microbiology: the Official Journal of the Spanish Society for Microbiology
Ketan D Patel, Sejal Purani, Sanjay S Ingle
Molecular characterization of 117 Bacillus thuringiensis (Bt) isolates from various geographical locations was previously done by PCR amplification of cry genes. In present investigation, diversity of cry genes from different soil types and climatic environments was studied using rarefaction method. Presence of cry1, cry2, cry3, 7, 8, cry4, cry5, 12, 14, 21, cry11, cry13 and cyt1 genes from Bt strains isolated from various regions of India was determined by PCR amplification. A varied distribution of cry genes and their profiles was found in four soil types...
February 2013: Journal of Invertebrate Pathology
Guillaume Tetreau, Mattia Alessi, Sylvie Veyrenc, Sophie Périgon, Jean-Philippe David, Stéphane Reynaud, Laurence Després
Bacillus thuringiensis subsp. israelensis is a bioinsecticide increasingly used worldwide for mosquito control. Despite its apparent low level of persistence in the field due to the rapid loss of its insecticidal activity, an increasing number of studies suggested that the recycling of B. thuringiensis subsp. israelensis can occur under specific, unknown conditions. Decaying leaf litters sampled in mosquito breeding sites in the French Rhône-Alpes region several months after a treatment were shown to exhibit a high level of larval toxicity and contained large amounts of spores...
December 2012: Applied and Environmental Microbiology
F P Santos, J Lopes, G T Vilas-Bôas, J A C Zequi
Aedes aegypti (Linnaeus) is the vector of dengue virus in Brazil. Bioinsecticides based on Bacillus thuringiensis have shown satisfactory results in the control of Diptera, due to the production of proteins called Cry and Cyt. The aim of the present study was to select B. thuringiensis isolates carrying the cry and cyt genes, which are efficient in the control of Ae. aegypti. A collection of 27 isolates of B. thuringiensis, derived from various regions in Brazil, was evaluated using selective bioassays against A...
April 2012: Acta Tropica
H Aboussaid, J C Vidal-Quist, K Oufdou, S El Messoussi, P Castañera, J González-Cabrera
Soils collected from five locations in the argan forest (an endemic plant) in Morocco were used to form the first collection of Bacillus thuringiensis (Bt) strains from this area (58 strains). Here we found that the argan forest is a major source of Bt, as 90.62% of the samples contained Bt strains. These strains produced mainly spherical or irregular crystals that in some cases remained adhered to the spore after cell lysis. There was no strain producing bipyramidal crystals, suggesting the absence of strains bearing crv1 genes...
August 2011: Environmental Technology
Olga Melnikov, Nadine Baranes, Monica Einav, Eitan Ben-Dov, Robert Manasherob, Mark Itsko, Arieh Zaritsky
A new gene, cry11Bb2 from a field isolate of Bacillus thuringiensis, was cloned for expression in Escherichia coli. The encoded protein, with a deduced molecular mass of 89.5 kDa, exhibits 97 and 79% identities with the overlap regions of Cry11Bb1 from B. thuringiensis ssp. medellin and Cry11Ba1 from ssp. jegathesan, respectively. It is however longer than Cry11Bb1 by 42 amino acids in its carboxy-terminus, of which 32 comprise 2 tandem repeats additional to the 5 existing in the latter polypeptide. Possible roles for this recurrent motif among Cry toxins and their accessory proteins, and for their encoding genes are proposed...
2011: Journal of Molecular Microbiology and Biotechnology
D H Sauka, R H Monella, G B Benintende
A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for detection of cry11 genes from Bacillus thuringiensis was established. Based on the analysis of conserved regions of the cry11 genes, 2 oligonucleotide primers were designed to amplify a 1459-bp fragment of the cry11Aa gene, and a 1471-bp of the cry11Ba and cry11Bb genes. The amplification products were digested with restriction endonuclease HinfI. Exotic B. thuringiensis strains and native isolates collected from soils, leaves and stored product dust of Argentina were analyzed to study the distribution of cry11 genes...
January 2010: Revista Argentina de Microbiología
J C Vidal-Quist, P Castañera, J González-Cabrera
A survey of Bacillus thuringiensis (Berliner) strains isolated from Spanish citrus orchards has been performed, and the strains were tested for insecticidal activity against the Mediterranean fruit fly Ceratitis capitata (Wiedemann), a key citrus pest in Spain. From a total of 150 environmental samples, 376 isolates were selected, recording a total B. thuringiensis index of 0.52. The collection was characterized by means of phase-contrast microscopy, SDS-PAGE, and PCR analysis with primer pairs detecting toxin genes cry1, cry2, cry3, cry4, cry5, cry7, cry8, cry9, cry10, cry11, cry12, cry14, cry17, cry19, cry21, cry27, cry39, cry44, cyt1, and cyt2...
August 2009: Journal of Microbiology and Biotechnology
Amin Nazarian, Rosa Jahangiri, Gholamreza Salehi Jouzani, Ali Seifinejad, Saeed Soheilivand, Omolbanin Bagheri, Mansoureh Keshavarzi, Khalil Alamisaeid
The characterization of the strains containing Coleopteran-specific and also putative novel cry genes in Iranian native Bacillus thuringiensis collection is presented. Characterization was based on PCR analysis using 31 general and specific primers for cry1B, cry1I, cry3A, cry3B, cry3C, cry7A, cry8A, cry8B, cry8C, cry14, cry18, cry26, cry28, cry34 and cry35 genes, protein band patterns as well as their insecticidal activity on Xanthogaleruca luteola Mull. larvae. Forty six isolates (65.7%) contained minimum one Coleopteran-active cry gene...
October 2009: Journal of Invertebrate Pathology
Dil Ara Abbas Bukhari, Abdul Rauf Shakoori
The six most toxic Pakistani isolates of Bacillus thuringiensis (SBS Bt-23, 29, 34, 37, 45 and 47), which were previously characterized for their toxicity against larvae of mosquito, Anopheles stephensi, and the presence of cry4 gene, were used for cry11 (cry4D) gene amplification. A 1.9-kb DNA fragment of cry11 gene was PCR-amplified, cloned in expression vector pT7-7, and then used for transformation of E. coli BL21C. The optimum expression was obtained with 1 mM IPTG at 37 degrees C for 3 h. This gene showed different percentage homologies at protein level with scattered mutations in the toxic region...
September 2009: Molecular Biology Reports
Glen Arrieta, Ana M Espinoza
Costa Rican natural ecosystems are among the most diverse in the world. For this reason, we isolated strains of the entomopathogenic bacteria Bacillus thuringiensis (Bt) to determine their diversity, distribution and abundance. A total of 146 Bt strains were obtained from environmental samples collected from diverse natural ecosystems and life zones of Costa Rica. We recovered Bt strains from 71%, 63%, 61% and 54% of soil samples, fresh leaves, other substrates and leaf litter respectively. Bt was isolated in 65% of the samples collected in the humid tropical forest in national parks (Braulio Carrillo, Gandoca Manzanillo, Sierpe, Hitoy Cerere, and Cahuita), and in 59% of the samples collected in the dry tropical forest (Parque Nacional Marino las Baulas, Palo Verde and Santa Rosa)...
March 2006: Revista de Biología Tropical
Gholamreza Salehi Jouzani, Ali Pourjan Abad, Ali Seifinejad, Rasoul Marzban, Khalil Kariman, Bahram Maleki
One hundred and twenty-eight Bacillus thuringiensis isolates from fields of different ecological regions of Iran were collected to study the distribution and diversity of Dipteran-specific cry and cyt genes. The percentage of samples with Bt showed significant differences between different regions and also between different fields. The most Bt frequency was observed in the soil samples collected from Caspianic zone (7%) and soils of cotton (17%). Characterization of isolates was based on morphological characteristics of crystals, plasmid profiles and protein band patterns as well as PCR analysis using general and specific primers for 22 different cry and cyt genes encoding proteins active against mosquitoes...
February 2008: Journal of Industrial Microbiology & Biotechnology
Glen Arrieta, Alejandro Hernández, Ana M Espinoza
The coffee berry borer Hypothenemus hampei Ferrari (Coleoptera: Scolytidae) was first reported infecting Costa Rican coffee plantations in the year 2000. Due to the impact that this plague has in the economy of the country, we were interested in seeking new alternatives for the biological control of H. hampei, based on the entomopathogenic bacteria Bacillus thuringiensis. A total of 202 B. thuringiensis isolates obtained from Costa Rican coffee plantations infested with H. hampei were analyzed through crystal morphology of the crystal inclusions and SDS-PAGE of 6-endotoxins, while 105 strains were further evaluated by PCR for the presence cry, cyt and vip genes...
September 2004: Revista de Biología Tropical
G Armengol, M C Escobar, M E Maldonado, S Orduz
AIM: To evaluate the genetic and molecular diversity and insecticidal activity of Bacillus thuringiensis isolates from all the natural regions of Colombia. METHODS AND RESULTS: A total of 445 isolates from a collection of B. thuringiensis were characterized. The parasporal crystal morphology that was most abundant was bipyramidal (60%). Almost 10% of the isolates were toxic to Spodoptera frugiperda and 5.6% against Culex quinquefasciatus larvae. cry gene content determined by PCR indicated that 10...
January 2007: Journal of Applied Microbiology
S Jara, P Maduell, S Orduz
AIMS: To evaluate the distribution of Bacillus thuringiensis strains from maize and bean phylloplane and their respective soils. METHODS AND RESULTS: B. thuringiensis was isolated from the phylloplane and soil of maize and bean from three municipalities in Antioquia, Colombia. Ninety six samples of phylloplane and 24 of soil were analyzed. A total of 214 isolates were obtained from 96 phylloplane samples while 59 isolates were recovered from 24 soil samples. Sixty five per cent and 12% of the phylloplane and soil isolates, respectively, showed activity against Spodoptera frugiperda...
July 2006: Journal of Applied Microbiology
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