Conjugal Transfer of a Toxin-Coding Megaplasmid from
 Bacillus thuringiensis
 subsp.
 israelensis
 to Mosquitocidal Strains of
 Bacillus sphaericus

Gammon, Katherine; Jones, Gareth Wyn; Hope, Steven J.; Oliveira, Cláudia Maria Fontes de; Regis, Lêda; Filha, Maria Helena N.L. Silva; Dancer, B. N.; Berry, Colin

doi:10.1128/aem.72.3.1766-1770.2006

Cited by 29 publications

(19 citation statements)

References 43 publications

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“…It is known that large plasmids can impose a metabolic burden on the strains that carry them, and that this can be a source of instability (Lucas et al ., 2005; Gammon et al ., 2006). We have shown here that pGRT1 is stable under non‐selective conditions, and that the rate of plasmid loss is below 10 −8 per cell and per cell generation, even when cells are cultured under suboptimal laboratory conditions.…”

Section: Discussionmentioning

confidence: 99%

The ttgGHI solvent efflux pump operon of Pseudomonas putida DOT‐T1E is located on a large self‐transmissible plasmid

Rodríguez‐Herva

García

Hurtado

et al. 2007

Environmental Microbiology

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Pseudomonas putida DOT-T1E is a solvent-tolerant strain able to grow in the presence of > 1% (v/v) toluene in the culture medium. A set of multidrug efflux pumps have been found to play a major role in the tolerance of this bacterium to organic solvents (Rojas et al., J Bacteriol 183: 3967-3973). In the course of studies of the mechanisms underlying solvent tolerance in DOT-T1E, we isolated a spontaneous solvent-sensitive mutant derivative which had lost the genes encoding the TtgGHI efflux pump, the most important extrusion element in quantitative terms. Genomic comparisons between the mutant and its parental strain by microarray analysis revealed that in addition to the ttgVW-ttgGHI gene cluster, another group of genes, highly similar to those found in the Tn4653A and ISPpu12 transposable elements of the TOL plasmid pWW0 from P. putida mt-2, were also absent from this strain. Further analysis demonstrated that strain DOT-T1E harboured a large plasmid (named pGRT1) that was lost from the solvent-sensitive mutant. Mapping analysis revealed that the ttgVW-ttgGHI genes and the Tn4653A-like transposon are borne by the pGRT1 plasmid. Plasmid pGRT1 is highly stable and its frequency of loss is below 10(-8) per cell per generation under a variety of growth conditions, including nutritional and physical stresses. The pGRT1 plasmid is self-transmissible, and its acquisition by the toluene-sensitive P. putida KT2440 and Pseudomonas aeruginosa PAO1 increased the recipient's tolerance to toluene up to levels similar to those exhibited by P. putida DOT-T1E. We discuss the importance and potential benefits of this plasmid for the development of bacteria with enhanced solvent tolerance, and its potential impact for bioremediation and whole-cell biotransformations.

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Section: Discussionmentioning

confidence: 99%

The ttgGHI solvent efflux pump operon of Pseudomonas putida DOT‐T1E is located on a large self‐transmissible plasmid

Rodríguez‐Herva

García

Hurtado

et al. 2007

Environmental Microbiology

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“…Another cry toxin-encoding element, pBtoxis from B. thuringiensis subsp. israelensis, is a plasmid that carries cry toxin genes, and while it is not self-transmissible, it can be mobilized by other plasmids from B. thuringiensis, such as pAW63 or pXO16 (11,21). The host strains of pHT73 and pBtoxis are two of the most widely used commercial B. thuringiensis biopesticide strains.…”

mentioning

confidence: 99%

Distribution, Diversity, and Potential Mobility of Extrachromosomal Elements Related to the Bacillus anthracis pXO1 and pXO2 Virulence Plasmids

Auwera

Timmery

et al. 2009

Appl Environ Microbiol

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The presence of a pXO1-and/or pXO2-like plasmid(s) in clinical isolates of Bacillus cereus sensu stricto and in strains of the biopesticide Bacillus thuringiensis has been reported recently, and the pXO2-like plasmid pBT9727 and another pXO2-like plasmid, pAW63, were found to be conjugative. In this study, a total of 1,000 B. cereus group isolates were analyzed for the presence of pXO1-and pXO2-like replicons and for the presence of pXO2-related conjugative modules. pXO1-and pXO2-like replicons were present in ca. 6.6% and 7.7% of random environmental samples, respectively, and ca. 1.54% of the strains were positive for pXO2-like transfer module genes. Only the strains harboring a pXO2-like replicon also contained the corresponding transfer genes. For the strains which contained a pXO1-and/or pXO2-like replicon(s), a large plasmid(s) whose size was similar to that of pXO1-like and/or pXO2-like plasmids was also observed, but none of these isolates were found to carry the Bacillus anthracis toxin or capsule virulence genes. Furthermore, 17 of 22 pXO2-like plasmids containing the transfer modules were able to self-transfer and to mobilize small plasmids. No pXO1-or pXO2-like plasmid lacking the cognate transfer modules has been found to have transfer potential. In the strains possessing the putative pXO2-like conjugative apparatus, variations in the presence of the group II introns B.th.I.1 and B.th.I.2 were observed, suggesting that there is important flexibility in the conjugation modules and their regulation. There was no consistent correlation between a pXO2-like repA dendrogram and the presence of the tra region or between a virB4 dendrogram and transfer ability. Discrepancies between pXO2-like repA and virB4 dendrograms were also observed, indicating that the evolution of pXO2 is an active process.The Bacillus cereus group includes Bacillus anthracis, B. cereus sensu stricto, Bacillus thuringiensis, Bacillus mycoides, Bacillus pseudomycoides, and Bacillus weihenstephanensis. All members of this group are genetically closely related and could be considered members of a single species or taxon (15,16,24,25). Several of their major phenotypic features, including their virulence spectra, are directly associated with large plasmids. In B. anthracis, the anthrax toxin and capsule genes responsible for anthrax disease are located on the 182-kb pXO1 and 95-kb pXO2 plasmids, respectively (26, 27). These plasmids are not self-transmissible but can be mobilized by conjugative plasmids, such as pXO14 from B. thuringiensis (29). The biopesticide properties that are the main characteristics of B. thuringiensis and distinguish it from B. cereus are due to large plasmids carrying cry genes. These genes are responsible for the production of different Cry toxins that form insecticidal crystal protein inclusions. Some of these large plasmids have been found to have conjugative transfer capability (12,20). For instance, plasmid pHT73 from B. thuringiensis subsp. kurstaki carries cry toxin genes and is conjugative (41). Another ...

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“…Berliner e Bacillus sphaericus Neide fazem parte de um complexo de linhagens bacterianas que produzem toxinas ativas para larvas de mosquitos (Charles et al 1996;Capalbo et al 2004;brar et al 2006;Gammon et al 2006;Osborn et al 2007). Produtos comerciais, possuindo os cristais produzidos por essas bactérias como princípio ativo, são amplamente utilizados em diferentes formulações para controle de espécies de mosquito vetores de patógenos (laCey 1984;yap et al 1991;alves et al 1999;DominiC amalraj et al 2000;alves et al 2001;DelGaDo et al 2001;alves et al 2006;osborn et al 2007).…”

Section: B Acillus Thuringiensis Israelensisunclassified

“…Produtos contendo B. spahericus apresentam melhor atividade em água poluída, quando comparado aos produtos formulados com B. thuringiensis israelensis (Wirth et al 2007), inclusive mostrando efeito residual superior ao verificado com a utilização de B. thuringiensis (thiery et al 1999; pontes et al 2005; Gammon et al 2006). Porém, estudos de campo demonstraram que o uso intensivo de formulações de B. sphaericus pode resultar na seleção de organismos resistentes, especialmente em populações do complexo Culex pipiens Linnaeus, 1758, limitando assim sua eficácia (rao et al 1995;silva-Filha et al 1995;yuan et al 2000;mulla et al 2003).…”

Section: B Acillus Thuringiensis Israelensisunclassified

Eficiência e Persistência de Três Produtos Comerciais à Base de Bacillus thuringiensis israelensis e Bacillus sphaericus no controle de Culicidae (Diptera) em Lagoas de Tratamento de Efluentes

et al. 2010

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S a ú d E P ú B l I c aResumo. A ação hematofágica exercida por fêmeas de algumas espécies de Culicidae sobre o homem e outros animais pode estar diretamente relacionada à transmissão de patógenos, além de provocar reações alérgicas e causar incômodo. O aparecimento de populações resistentes aos inseticidas químicos impulsiona o uso de métodos de controle alternativos, principalmente o biológico. Objetivando testar a eficiência e persistência de produtos comerciais com principio ativo a base de Bacillus thuringiensis israelensis Berliner e Bacillus sphaericus Neide foram realizados experimentos em três lagoas de tratamento de efluentes, sobre larvas de Culicidae. Testou-se Vectolex (formulação granulada de B. sphaericus), Sphaericus (formulação líquida de B. sphaericus) e Bt-horus (formulação líquida de B. thuringiensis). As aplicações foram realizadas quinzenalmente com avaliações realizadas a 0, 24, 48, 72 e 120 horas após a aplicação. As lagoas estavam colonizadas por Culex nigripalpus Theobald (1,5%), Culex saltanensis Dyar (2,25%) e Culex quinquefasciatus Say (96,25%). Com o produto Bt horus, registrou-se redução larval de 89,06%, 83,97% e 89,96% respectivamente a 24, 48 e 72 horas após a aplicação. Nos produtos contendo B. sphaericus, respectivamente na formulação granulada e líquida observou-se uma redução de 98,89% e 98,34%, após 24 horas da aplicação e de 99,79% e 99,78% após 48 horas. Os produtos e as diferentes formulações foram eficientes no controle de larvas das três espécies de culicídeos em lagoas com grande quantidade de matéria orgânica, porém a persistência verificada foi de dois e três dias para produtos contendo respectivamente B. sphaericus e B. thuringiensis israelensis. Palavras-Chave: Água poluída; Controle biológico; Culex Efficiency and Persistence of Three Commercial Products Based on Bacillus thuringiensis israelensis and Bacillus sphaericus in Controlling Culicidae (Diptera) in Effluent Treatment LagoonsAbstract. The hematofagic effect caused by females belonging to some species of Culicidae on humans and animals can be directly related to pathogen transmission, allergic reactions and uneasiness. The emergence of populations resistant to chemical insecticides has fostered the use of alternative methods, mainly biological control. The trials were conducted in three effluent treatment lagoons, on larvae of Culicidae to test the efficiency and persistence of commercial products whose active principles are based on Bacillus thuringiensis israelensis Berliner and Bacillus sphaericus Neide. The products tested were Vectolex (a granulated formulation of B. sphaericus), Sphaericus (a liquid formulation of B. sphaericus) and Bt-horus (a liquid formulation of B. thuringiensis). The products were applied biweekly and evaluations were conducted 0, 24, 48, 72, and 120 hours after each application. The lagoons were colonized by Culex nigripalpus Theobald (1.5%), Culex saltanensis Dyar (2.25%), and Culex quinquefasciatus Say (96.25%). Bt horus reduced larvae by 89.06%, 83.97% and 89.96% at 24, 48 ...

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Conjugal Transfer of a Toxin-Coding Megaplasmid from Bacillus thuringiensis subsp. israelensis to Mosquitocidal Strains of Bacillus sphaericus

Cited by 29 publications

References 43 publications

The ttgGHI solvent efflux pump operon of Pseudomonas putida DOT‐T1E is located on a large self‐transmissible plasmid

The ttgGHI solvent efflux pump operon of Pseudomonas putida DOT‐T1E is located on a large self‐transmissible plasmid

Distribution, Diversity, and Potential Mobility of Extrachromosomal Elements Related to the Bacillus anthracis pXO1 and pXO2 Virulence Plasmids

Eficiência e Persistência de Três Produtos Comerciais à Base de <i>Bacillus thuringiensis israelensis</i> e <i>Bacillus sphaericus</i> no controle de Culicidae (Diptera) em Lagoas de Tratamento de Efluentes

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