Isolation of
            <i>Bacillus thuringiensis</i>
            from Stored Tobacco and
            <i>Lasioderma serricorne</i>
            (F.)

Kaelin, Pascale; Morel, P. C. H.; Gadani, Ferruccio

doi:10.1128/aem.60.1.19-25.1994

Cited by 55 publications

(25 citation statements)

References 24 publications

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“…Following this technique they isolated Bacillus thuringiensis from environmental samples with more than 10 9 bacilli g )1 of soil. Although this method has been successfully and extensively employed (Martin and Travers 1989;Carozzi et al 1991;Kaelin et al 1994) for the isolation of soil Bacillus species, each sample is required to undergo a lengthy isolation procedure and it results in the selection of both toxic and atoxic strains of spore-forming bacilli.…”

Section: Discussionmentioning

confidence: 99%

Novel cost-effective method of screening soils for the presence of mosquito-pathogenic bacilli

Dhindsa

Sangodkar

2002

Lett Appl Microbiol

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Aims: The aim was to simplify the cumbersome conventional process of isolating virulent bacilli, which involves isolating all bacilli strains from a source followed by screening for strains that are effective for bio‐control of mosquito vectors. Methods: A new simplified technique involving eight steps was devised for screening soil samples for the presence of mosquito‐pathogenic bacilli before isolating individual strains. Results: Using the new technique, we obtained eight bacilli strains (KSD1‐8) showing pathogenic activity against mosquito larvae from three out of 10 soil samples screened. These strains were characterized, identified and the main bioassay tests were performed with three most promising strains (KSD‐4, KSD‐7 and KSD‐8), and their pathogenic activity against Anopheles stephensi Liston, Culex quinquefasciatus, Say and Aedes aegypti Linnaeus compared well with commercial reference strains of B. thuringiensis israelensis and B. sphaericus. Significance and Impact of the Study: The new technique of screening soil samples for the presence of virulent pathogenic strains of bacilli against mosquito larvae proved quick, efficient and cost effective.

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Section: Discussionmentioning

confidence: 99%

Novel cost-effective method of screening soils for the presence of mosquito-pathogenic bacilli

Dhindsa

Sangodkar

2002

Lett Appl Microbiol

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“…Bacillus thuringiensis morrisoni 1925 and B.t. morrisoni 3123 was kindly provided by Prof. Feruccio Gadani, Philip Morris Europe S.A., Neuchatel, Switzerland (Kaelin et al. 1994).…”

Section: Methodsmentioning

confidence: 99%

Inorganic phosphate has a crucial effect on Cry3Aa delta-endotoxin production

Kurt

Özkan

Özcengiz

2005

Lett Appl Microbiol

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Aims:The study aimed at increasing Cry3Aa d-endotoxin production by a local isolate of Bacillus thuringiensis (B.t. strain Mm2). To this end, different nutritional conditions were tested for their effects on Cry3Aa yields. Methods and Results: Bacillus thuringiensis Mm2 was grown by shaking at 30°C in different media. Samples were taken from the cultures at intervals and used for protein extraction. SDS-PAGE was performed for toxin analysis. Inclusion of inorganic phosphate (Pi) into the Difco's sporulation medium at an increased level of 200 mmol l )1 caused a fivefold increase (from 3 to 15AE6 lg ml )1 ) in toxin production. Omission of FeSO 4 from the medium decreased this yield by half. Resuspension experiments suggested catabolite repression of toxin biosynthesis by glucose. The inclusion of high Pi invariably increased toxin synthesis, even in the absence of sugars. Conclusions: Inorganic phosphate had the most striking effect on toxin biosynthesis. Iron effect was found to be unique to our isolate whereas Pi effect seemed to be common to the biosynthesis of Cry3Aa-type toxins. Stimulation of toxin synthesis by Pi did not seem to represent a relief from glucose repression. Significance and Impact of the Study: Bacillus thuringiensis is the most versatile biopesticide for use in pest management. Regarding cost-effectiveness of related fermentations, high Pi supplement drastically increases Coleoptera-specific toxin synthesis.

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“…The diversity of habitats from which subspecies of Bt strains have been isolated indicates that the ecology of this bacterium is probably very complex. For example, Bt has been isolated from habitats as different as soil, which is thought to be the preferred habitat (DeLucca et al 1981;Martin and Travers 1989;Chilcott and Wigley 1993), grain mills (DeLucca et al 1982), stored products (Kaelin et al 1994), rearing facilities (Dulmage 1970), the phylloplane (Smith and Couche 1991) and diseased insects (Feitelson et al 1992;Wiwat et al 2000). Recent studies on insecticidal crystal protein (ICP) genes are beginning to provide insight into the possible origin of the diversity of subspecies.…”

Section: Introductionmentioning

confidence: 99%

cry Genes profiling and the toxicity of isolates of Bacillus thuringiensis from soil samples against American bollworm, Helicoverpa armigera

Baig

Bukhari

Shakoori

2010

Journal of Applied Microbiology

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Aims: The aim of this study was to search for Bacillus thuringiensis (Bt) harbouring cry1A gene which could effectively control cotton pest, American bollworm, Helicoverpa armigera. Methods and Results: cry gene profiling of 50 Bt isolates showed the presence of cry1, cry2, cry3, cry4, cry7, cry8 and cry9 genes. None of the isolates harboured cry1 gene alone. It was always found in combination with cry3. There was no isolate positive for cry10 gene. Considering isolates with single cry genes, the frequency of cry4 was predominant (22%) followed cry2 (6%), cry3 (4%) and cry8 (2%). Isolates having two cry genes in combination had 14% incidence for cry2 + cry4, 12% for cry3 + cry4 and 10% for cry1 + cry3. The most dominant three gene linkage was cry1 + cry3 + cry4. Further profiling of cry1 gene showed that cry1K gene was abundantly present in all combinations such as cry1A, cry1D, cry1F and cry1I. However, cry1C existed independent of other subtypes. Finally, the Bt isolates with cry1A were analyzed for 16S rRNA gene, which showed two distinct groups of isolates on the basis of sequence homology. Bioassays of spore-crystal mixtures of 8, 17, 21 and 26 harbouring cry1 against neonate larvae of H. armigera showed LC 50 1288, 1202, 467AE7, 524AE8 and 108AE5 lg ml )1 . The SBS-Bt26 showed fourfold higher toxicity than the cry 1Ac harbouring positive control, HD-73. Conclusions: None of the isolates harboured single cry 1 gene. They were always in combination of two or three genes. A Bt isolate (Bt26) had fourfold higher toxicity against H. armigera larvae compared with the positive control HD 73 and hence can be commercially exploited to control insect pest. Significance and Impact of the Study: The inter relationship between the cry genes content and the toxicity may allow better understanding of Bt ecology.

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Isolation of Bacillus thuringiensis from Stored Tobacco and Lasioderma serricorne (F.)

Cited by 55 publications

References 24 publications

Novel cost-effective method of screening soils for the presence of mosquito-pathogenic bacilli

Novel cost-effective method of screening soils for the presence of mosquito-pathogenic bacilli

Inorganic phosphate has a crucial effect on Cry3Aa delta-endotoxin production

cry Genes profiling and the toxicity of isolates of Bacillus thuringiensis from soil samples against American bollworm, Helicoverpa armigera

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