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Dmitrović S, Pajčin I, Lukić N, Vlajkov V, Grahovac M, Grahovac J, Jokić A. Taguchi Grey Relational Analysis for Multi-Response Optimization of Bacillus Bacteria Flocculation Recovery from Fermented Broth by Chitosan to Enhance Biocontrol Efficiency. Polymers (Basel) 2022; 14:polym14163282. [PMID: 36015554 PMCID: PMC9413004 DOI: 10.3390/polym14163282] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/05/2022] [Accepted: 08/09/2022] [Indexed: 02/05/2023] Open
Abstract
Degradation of environment is a challenge to crop production around the world. Biological control of various plant diseases using antagonistic bacteria is an encouraging alternative to traditionally used chemical control strategies. Chitosan as a well-known natural flocculation agent also exhibits antimicrobial activity. The goal of this study was to investigate a dual nature of chitosan in flocculation of Bacillus sp. BioSol021 cultivation broth intended for biocontrol applications. Experiments were performed based on L18 standard Taguchi orthogonal array design with five input parameters (chitosan type and dosage, pH value, rapid and slow mixing rates). In this study, the grey relational analysis was used to perform multi-objective optimization of the chosen responses, i.e., flocculation efficiency and four inhibition zone diameters against the selected phytopathogens. The results have indicated a great potential of a highly efficient method for removal of the Bacillus bacteria from the cultivation broth using chitosan. The good flocculation efficiency and high precipitate antimicrobial activity against the selected phytopathogens were achieved. It has been shown that multiple flocculation performance parameters were improved, resulting in slightly improved response values.
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Affiliation(s)
- Selena Dmitrović
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Ivana Pajčin
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
- Correspondence: (I.P.); (J.G.)
| | - Nataša Lukić
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Vanja Vlajkov
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
| | - Mila Grahovac
- Faculty of Agriculture, University of Novi Sad, Trg Dositeja Obradovića 8, 21000 Novi Sad, Serbia
| | - Jovana Grahovac
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
- Correspondence: (I.P.); (J.G.)
| | - Aleksandar Jokić
- Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia
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Salamun, Fatimah, Fauzi A, Praduwana SN, Ni'matuzahroh. Larvicidal toxicity and parasporal inclusion of native Bacillus thuringiensis BK5.2 against Aedes aegypti. J Basic Clin Physiol Pharmacol 2021; 32:379-384. [PMID: 34214353 DOI: 10.1515/jbcpp-2020-0472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 02/21/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Native Bacillus thuringiensis BK5.2, isolated from soil of Baluran National Park, East Java, Indonesia, has been shown to be toxic against Aedes aegypti larvae. This study aims to determine the strength and the speed of the toxicity of B. thuringiensis BK5.2 against A. aegypti larvae in lethal concentration (LC) and lethal time (LT), as well as detection of toxin structure and parasporal inclusion. METHODS LC values were determined by the mortality of A. aegypti third instar larvae after 24 and 48 h exposure to five various concentrations of B. thuringiensis BK5.2, while LT values were determined based on the mortality of A. aegypti third instar larvae due to exposure to LC90 concentration at 0; 0.5; 1; 2; 4; 8; 10; 20; 24; and 48 h. Larvicidal toxicity was determined based on value of LC50 and LC90 (CFU/mL), as well as LT50 and LT90 (hours) analysed with Probit analysis. Parasporal inclusion was detected using transmission electron microscope (TEM) and scanning electron microscope (SEM). RESULTS Based on bioassay, LC50 and LC90 values were 11.6 × 106 and 22.7 × 106 CFU/mL, respectively, at 24 h exposure, as well as 8.3 × 106 and 15.4 × 106 CFU/mL, respectively, at 48 h exposure, while the value of LT50 and LT90 were 19.0 and 26.6 h, respectively. Morphological observation of the dead larvae showed there was damage on abdomen and thorax region. Detection by TEM and SEM showed there was cuboidal parasporal inclusion. CONCLUSIONS Native B. thuringiensis BK5.2 has high toxicity against A. aegypti larvae and detected flatcuboidal toxin in parasporal inclusion.
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Affiliation(s)
- Salamun
- Faculty of Science and Technology, University -CoE- Research Center for Bio-Molecule Engineering, Universitas Airlangga, Surabaya, Indonesia
| | - Fatimah
- Faculty of Science and Technology, University -CoE- Research Center for Bio-Molecule Engineering, Universitas Airlangga, Surabaya, Indonesia
| | - Ahmad Fauzi
- Faculty of Science and Technology, Universitas Airlangga, Surabaya, Indonesia
| | - Seling N Praduwana
- Faculty of Science and Technology, Universitas Airlangga, Surabaya, Indonesia
| | - Ni'matuzahroh
- Faculty of Science and Technology, Faculty of Advanced Technology and Multidiscipline, University -CoE- Research Center for Bio-Molecule Engineering, Universitas Airlangga, Surabaya, Indonesia
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Potential for Bacillus thuringiensis and Other Bacterial Toxins as Biological Control Agents to Combat Dipteran Pests of Medical and Agronomic Importance. Toxins (Basel) 2020; 12:toxins12120773. [PMID: 33291447 PMCID: PMC7762171 DOI: 10.3390/toxins12120773] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 11/24/2020] [Accepted: 12/03/2020] [Indexed: 11/16/2022] Open
Abstract
The control of dipteran pests is highly relevant to humans due to their involvement in the transmission of serious diseases including malaria, dengue fever, Chikungunya, yellow fever, zika, and filariasis; as well as their agronomic impact on numerous crops. Many bacteria are able to produce proteins that are active against insect species. These bacteria include Bacillus thuringiensis, the most widely-studied pesticidal bacterium, which synthesizes proteins that accumulate in crystals with insecticidal properties and which has been widely used in the biological control of insects from different orders, including Lepidoptera, Coleoptera, and Diptera. In this review, we summarize all the bacterial proteins, from B. thuringiensis and other entomopathogenic bacteria, which have described insecticidal activity against dipteran pests, including species of medical and agronomic importance.
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Genome wide underpinning of antagonistic and plant beneficial attributes of Bacillus sp. SBA12. Genomics 2020; 112:2894-2902. [DOI: 10.1016/j.ygeno.2020.03.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/28/2020] [Accepted: 03/30/2020] [Indexed: 01/16/2023]
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El-Kawokgy TMA, Hussein HA, Aly NAH, Mohamed SAH. Highly toxic and broad-spectrum insecticidal local Bacillus strains engineered using protoplast fusion. Can J Microbiol 2014; 61:38-47. [PMID: 25485592 DOI: 10.1139/cjm-2014-0532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Protoplast fusion was performed between a local Bacillus thuringiensis UV-resistant mutant 66/1a (Bt) and Bacillus sphaericus GHAI (Bs) to produce new Bacillus strains with a wider spectrum of action against different insects. Bt is characterized as sensitive to polymyxin and streptomycin and resistant to rifampicin and has shown 87% mortality against Spodoptera littoralis larvae at concentration of 1.5 × 10(7) cells/mL after 7 days of feeding; Bs is characterized as resistant to polymyxin and streptomycin and sensitive to rifampicin and has been shown to have 100% mortality against Culex pipiens after 1 day of feeding at the same concentration as that of Bt. Among a total of 64 Bt::Bs fusants produced on the selective medium containing polymyxin, streptomycin, and rifampicin, 17 fusants were selected because of their high mortality percentages against S. littoralis (Lepidoptera) and C. pipiens (Diptera). While Bt harboured 3 plasmids (600, 350, and 173 bp) and Bs had 2 plasmids (544 and 291 bp), all the selected fusants acquired plasmids from both parental strains. SDS-PAGE protein analysis of the 17 selected fusants and their parental strains confirmed that all fusant strains acquired and expressed many specific protein bands from the 2 parental strains, especially the larvicidal proteins to both lepidopteran and dipteran species with molecular masses of 65, 70, 80, 88, 100, and 135 kDa. Four protein bands with high molecular masses of 281, 263, 220, and 190 kDa, which existed in the Bt parental strain and did not exist in the Bs parental strain, and 2 other protein bands with high molecular masses of 185 and 180 kDa, which existed in the Bs parental strain and did not exist in the Bt parental strain, were expressed in most fusants. The results indicated the expression of some cry genes encoded for insecticidal crystal proteins from Bt and the binary toxin genes from Bs in all fusant strains. The recombinant fusants have more efficient and potential values for agricultural application compared with both the insecticidal Bt and the mosquitocidal Bs strains alone against S. littoralis and C. pipiens larvae, respectively.
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Allievi MC, Palomino MM, Prado Acosta M, Lanati L, Ruzal SM, Sánchez-Rivas C. Contribution of S-layer proteins to the mosquitocidal activity of Lysinibacillus sphaericus. PLoS One 2014; 9:e111114. [PMID: 25354162 PMCID: PMC4213006 DOI: 10.1371/journal.pone.0111114] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 09/26/2014] [Indexed: 11/25/2022] Open
Abstract
Lysinibacillus sphaericus strains belonging the antigenic group H5a5b produce spores with larvicidal activity against larvae of Culex mosquitoes. C7, a new isolated strain, which presents similar biochemical characteristics and Bin toxins in their spores as the reference strain 2362, was, however, more active against larvae of Culex mosquitoes. The contribution of the surface layer protein (S-layer) to this behaviour was envisaged since this envelope protein has been implicated in the pathogenicity of several bacilli, and we had previously reported its association to spores. Microscopic observation by immunofluorescence detection with anti S-layer antibody in the spores confirms their attachment. S-layers and BinA and BinB toxins formed high molecular weight multimers in spores as shown by SDS-PAGE and western blot detection. Purified S-layer from both L. sphaericus C7 and 2362 strain cultures was by itself toxic against Culex sp larvae, however, that from C7 strain was also toxic against Aedes aegypti. Synergistic effect between purified S-layer and spore-crystal preparations was observed against Culex sp. and Aedes aegypti larvae. This effect was more evident with the C7 strain. In silico analyses of the S-layer sequence suggest the presence of chitin-binding and hemolytic domains. Both biochemical characteristics were detected for both S-layers strains that must justify their contribution to pathogenicity.
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Affiliation(s)
- Mariana Claudia Allievi
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - María Mercedes Palomino
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Mariano Prado Acosta
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Leonardo Lanati
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Sandra Mónica Ruzal
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Carmen Sánchez-Rivas
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
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Park HW, Bideshi DK, Federici BA. The 20-kDa protein of Bacillus thuringiensis subsp. israelensis enhances Bacillus sphaericus 2362 bin toxin synthesis. Curr Microbiol 2007; 55:119-24. [PMID: 17597341 DOI: 10.1007/s00284-006-0359-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Accepted: 01/01/2007] [Indexed: 11/26/2022]
Abstract
Improving the amount of protein endotoxins synthesized by Bacillus thuringiensis and B. sphaericus per unit of culture medium is important because higher yields typically correlate with higher insecticidal activity per unit weight of spore/toxin mixtures. Higher levels of synthesis can also result in larger crystals that could persist for longer periods in the environment. Improving endotoxin production in B. thuringiensis can be achieved by manipulating genetic elements that regulate protein synthesis at the transcriptional, translational, and even posttranslational levels. In the present study, we used a combination of genetic elements to improve yields of B. sphaericus 2362 binary toxin (Bin) in B. thuringiensis. Our results show that a 20-kDa chaperone-like protein, which occurs as the third open-reading frame in the cry11Aa operon, improves Bin yields when expression of the genes encoding this binary toxin is driven by the native bin promoter, cyt1A promoters, or a novel cyt1A-p/STAB-SD expression system, the latter of which yields maximal levels of Bin synthesis. The 20-kDa helper protein increased Bin toxin levels in B. thuringiensis by as much as 53% and concomitant toxicity by at least 90% when Bin was produced using the cyt1A promoters.
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Affiliation(s)
- Hyun-Woo Park
- John A. Mulrennan, Sr., Public Health Entomology Research and Education Center, College of Engineering Sciences, Technology, and Agriculture, Florida A & M University, 4000 Frankford Avenue, Panama City, FL 32405, USA.
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Federici BA, Park HW, Bideshi DK, Wirth MC, Johnson JJ, Sakano Y, Tang M. Developing recombinant bacteria for control of mosquito larvae. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2007; 23:164-75. [PMID: 17853605 DOI: 10.2987/8756-971x(2007)23[164:drbfco]2.0.co;2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Genetic engineering techniques have been used to significantly improve mosquito larvicides based on the bacteria Bacillus thuringiensis (Bt) subsp. israelensis (Bti) and Bacillus sphaericus (Bs). These new larvicides hold excellent promise for providing better and more cost-effective control of nuisance mosquitoes and vectors of important diseases, including the anopheline vectors of malaria and culicine vectors responsible for filariasis and viral encephalitides. The toxicity of Bti and Bs is due primarily to endotoxin proteins produced during sporulation. After ingestion by larvae, these are activated and destroy the larval stomach, quickly resulting in death. By cloning the genes encoding various endotoxins from Bt and Bs species, and engineering these for high levels of synthesis, we have been able to generate recombinant bacterial strains based on Bti that are more than 10 times as effective as the conventional strains of Bti or Bs that serve as the active ingredients of commercial bacterial larvicides currently used for mosquito control. The best of these recombinants contain all major Bti endotoxins, specifically, Cry4A, Cry4B, Cry11A, and Cyt1A, plus the binary (Bin) endotoxin of Bs, the principal mosquitocidal protein responsible for the activity of this species. The presence of Cyt1A in these recombinants, which synergizes Cry toxicity and delays resistance to these proteins and Bs Bin, should enable long term use of these recombinants with little if any development of resistance. In the field, these new recombinants should be particularly effective larvicides against most important vectors and nuisance species of the genus Culex, the malaria vectors Anopheles gambiae and An. arabiensis, and species of Aedes and Ochlerotatus sensitive to Bs.
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Affiliation(s)
- Brian A Federici
- Department of Entomology, University of California, Riverside, Riverside, CA 92521, USA
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Gammon K, Jones GW, Hope SJ, de Oliveira CMF, Regis L, Silva Filha MHNL, Dancer BN, Berry C. Conjugal transfer of a toxin-coding megaplasmid from Bacillus thuringiensis subsp. israelensis to mosquitocidal strains of Bacillus sphaericus. Appl Environ Microbiol 2006; 72:1766-70. [PMID: 16517620 PMCID: PMC1393184 DOI: 10.1128/aem.72.3.1766-1770.2006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Accepted: 12/12/2005] [Indexed: 11/20/2022] Open
Abstract
Both Bacillus sphaericus and Bacillus thuringiensis subsp. israelensis produce mosquitocidal toxins during sporulation and are extensively used in the field for control of mosquito populations. All the known toxins of the latter organism are known to be encoded on a large plasmid, pBtoxis. In an attempt to combine the best properties of the two bacteria, an erythromycin resistance-marked pBtoxis plasmid was transferred to B. sphaericus by a mating technique. The resulting transconjugant bacteria were significantly more toxic to Aedes aegypti mosquitoes and were able to overcome resistance to B. sphaericus in a resistant colony of Culex quinquefasciatus, apparently due to the production of Cry11A but not Cry4A or Cry4B. The stability of the plasmid in the B. sphaericus host was moderate during vegetative growth, but segregational instability was observed, which led to substantial rates of plasmid loss during sporulation.
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Affiliation(s)
- Katherine Gammon
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, United Kingdom
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Promdonkoy B, Promdonkoy P, Panyim S. Co-expression of Bacillus thuringiensis Cry4Ba and Cyt2Aa2 in Escherichia coli revealed high synergism against Aedes aegypti and Culex quinquefasciatus larvae. FEMS Microbiol Lett 2005; 252:121-6. [PMID: 16168580 DOI: 10.1016/j.femsle.2005.08.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 06/29/2005] [Accepted: 08/25/2005] [Indexed: 11/28/2022] Open
Abstract
Cry4Ba is a delta-endotoxin produced by Bacillus thuringiensis subsp. israelensis and Cyt2Aa2 is a cytolytic delta-endotoxin produced by B. thuringiensis subsp. darmstadiensis. Cry4Ba produced in Escherichia coli was toxic to Aedes aegypti larvae (LC(50)=140 ng ml(-1)) but virtually inactive to Culex quinquefasciatus larvae. Cyt2Aa2 expressed in E. coli exhibited moderate activity against A. aegypti and C. quinquefasciatus larvae with LC(50) values of 350 and 250 ng ml(-1), respectively. Co-expression of both toxins in E. coli dramatically increased toxicity to both A. aegypti andC. quinquefasciatus larvae (LC(50)=7 and 20 ng ml(-1), respectively). This is the first report to demonstrate that Cry4Ba and Cyt2Aa2 have high synergistic activity against C. quinquefasciatus larvae.
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Affiliation(s)
- Boonhiang Promdonkoy
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand.
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Wirth MC, Jiannino JA, Federici BA, Walton WE. Synergy between toxins of Bacillus thuringiensis subsp. israelensis and Bacillus sphaericus. JOURNAL OF MEDICAL ENTOMOLOGY 2004; 41:935-941. [PMID: 15535624 DOI: 10.1603/0022-2585-41.5.935] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Synergistic interactions among the multiple endotoxins of Bacillus thuringiensis subsp. israelensis de Barjac play an important role in its high toxicity to mosquito larvae and the absence of insecticide resistance in populations treated with this bacterium. A lack of toxin complexity and synergism are the apparent causes of resistance to Bacillus sphaericus Neide in particular Culex field populations. To identify endotoxin combinations of the two Bacillus species that might improve insecticidal activity and manage mosquito resistance to B. sphaericus, we tested their toxins alone and in combination. Most combinations of B. sphaericus and B. t. subsp. israelensis toxins were synergistic and enhanced toxicity relative to B. sphaericus, particularly against Culex quinquefasciatus Say larvae resistant to B. sphaericus and Aedes aegypti (L.), a species poorly susceptible to B. sphaericus. Toxicity also improved against susceptible Cx. quinquefasciatus. For example, when the CytlAa toxin from B. t. subsp. israelensis was added to Bin and Cry toxins, or when native B. t. subsp. israelensis was combined with B. sphaericus, synergism values as high as 883-fold were observed and combinations were 4-59,000-fold more active than B. sphaericus. These data, and previous studies using cytolytic toxins, validate proposed strategies for improving bacterial larvicides by combining B. sphaericus with B. t. subsp. israelensis or by engineering recombinant bacteria that express endotoxins from both strains. These combinations increase both endotoxin complexity and synergistic interactions and thereby enhance activity and help avoid insecticide resistance.
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Affiliation(s)
- Margaret C Wirth
- Department of Entomology, University of California, Riverside, CA 92521, USA
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Nielsen-Leroux C, Pasteur N, Prètre J, Charles JF, Sheikh HB, Chevillon C. High resistance to Bacillus sphaericus binary toxin in culex pipiens (Diptera: Culicidae): the complex situation of west Mediterranean countries. JOURNAL OF MEDICAL ENTOMOLOGY 2002; 39:729-735. [PMID: 12349855 DOI: 10.1603/0022-2585-39.5.729] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This study was aimed at clarifying the nature of the resistance to Bacillus sphaericus Neide (Bs) that Culex pipiens L. has developed in west Mediterranean countries, France, and Tunisia. Two recessive and sex-linked mutants, sp-1R and sp-2R, were previously detected in southern France. Here, the Tunisian resistance was also shown to involve a single recessive and sex-linked gene that was temporarily named sp-T(R). In addition, sp-1R, sp-2R, and sp-T(R) were shown to separately confer a similar high resistance level (> 5,000-fold) in the homozygous state. Knowing that sp-1R resistance does not alter the binding of Bs binary toxin to its specific receptor, we investigated this character in sp-2RR and sp-T(RR) homozygotes. This was performed by in vitro experiments in which larval brush border membrane fractions (BBMF) were exposed to the 125I-Bin2 toxin of B. sphaericus strain 1593. The toxin-receptor binding was found disrupted by sp-2R but not by sp-T(R). Comparing the binding kinetics among nine Culex pipiens strains of diverse origins revealed that the Bs receptors of sp-1RR and Sp-T(RR) homozygous larvae were displaying the highest affinity toward Bs binary toxins. These results are discussed with regard to alternative assumptions on the dynamics of high Bs-resistance and on the emerging possibilities to test them in a near future.
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Khasdan V, Ben-Dov E, Manasherob R, Boussiba S, Zaritsky A. Toxicity and synergism in transgenic Escherichia coli expressing four genes from Bacillus thuringiensis subsp. israelensis. Environ Microbiol 2001; 3:798-806. [PMID: 11846773 DOI: 10.1046/j.1462-2920.2001.00253.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The genes cyt1Aa and p20, encoding, respectively, cytolytic and accessory proteins of Bacillus thuringiensis subsp. israelensis, were introduced into previously constructed clones expressing cry4Aa and cry11Aa in Escherichia coli (Ben-Dov et al., 1995). Fifteen clones with all possible combinations of the four genes were obtained and found to express the genes included. Two new combinations, pVE4-ADRC and pVE4-ARC, expressing cyt1Aa, p20 and cry4Aa, with or without cry11Aa, respectively, were more toxic than their counterparts without cyt1Aa. They displayed the highest toxicity against Aedes aegypti larvae ever reached in transgenic bacteria. Five out of the six clones (except pVE4-DC) containing cry4Aa or cry11Aa (with or without p20) displayed varying levels of synergism with cyt1Aa: they are 1.5-to 34-fold more toxic than the respective clones without cyt1Aa against exposed larvae. Their lethal times also decreased (they kill larvae quicker), more so at higher cell concentrations. These clones are anticipated to dramatically reduce the likelihood of resistant development in the target organisms (Wirth et al., 1997).
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Affiliation(s)
- V Khasdan
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er-Sheva 84105, Israel
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Regis L, Silva-Filha MH, Nielsen-LeRoux C, Charles JF. Bacteriological larvicides of dipteran disease vectors. Trends Parasitol 2001; 17:377-80. [PMID: 11685898 DOI: 10.1016/s1471-4922(01)01953-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The apparent success in vector control observed between 1950 and 1970 was followed by worldwide resistance to organosynthetic insecticides wherever they were used intensively. Insect resistance to one or more categories of insecticides has limited the effectiveness of these compounds, and their non-selective mode of action adversely affects non-target organisms. This scenario highlights the need for selective agents in integrated vector control programs. This article gives an overview of the main fundamental and applied research topics on entomopathogenic bacteria in relation to their role in vector control.
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Affiliation(s)
- L Regis
- Fundação Oswaldo Cruz-Fiocruz, CPqAM, Dept Entomology, Av Moraes Rego s/n 50670.420 Recife, PE, Brazil.
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Wirth MC, Delécluse A, Walton WE. Cyt1Ab1 and Cyt2Ba1 from Bacillus thuringiensis subsp. medellin and B. thuringiensis subsp. israelensis Synergize Bacillus sphaericus against Aedes aegypti and resistant Culex quinquefasciatus (Diptera: Culicidae). Appl Environ Microbiol 2001; 67:3280-4. [PMID: 11425753 PMCID: PMC93012 DOI: 10.1128/aem.67.7.3280-3284.2001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interaction of two cytolytic toxins, Cyt1Ab from Bacillus thuringiensis subsp. medellin and Cyt2Ba from Bacillus thuringiensis subsp. israelensis, with Bacillus sphaericus was evaluated against susceptible and resistant Culex quinquefasciatus and the nonsensitive species Aedes aegypti. Mixtures of B. sphaericus with either cytolytic toxin were synergistic, and B. sphaericus resistance in C. quinquefasciatus was suppressed from >17,000- to 2-fold with a 3:1 mixture of B. sphaericus and Cyt1Ab. This trait may prove useful for combating insecticide resistance and for improving the activity of microbial insecticides.
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Affiliation(s)
- M C Wirth
- Department of Entomology, University of California, Riverside, California 92521, USA.
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Gutierrez P, Alzate O, Orduz S. A theoretical model of the tridimensional structure of Bacillus thuringiensis subsp. medellin Cry 11Bb toxin deduced by homology modelling. Mem Inst Oswaldo Cruz 2001; 96:357-64. [PMID: 11313644 DOI: 10.1590/s0074-02762001000300013] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cry11Bb is an insecticidal crystal protein produced by Bacillus thuringiensis subsp. medellin during its stationary phase; this partial differential-endotoxin is active against dipteran insects and has great potential for mosquito borne disease control. Here, we report the first theoretical model of the tridimensional structure of a Cry11 toxin. The tridimensional structure of the Cry11Bb toxin was obtained by homology modelling on the structures of the Cry1Aa and Cry3Aa toxins. In this work we give a brief description of our model and hypothesize the residues of the Cry11Bb toxin that could be important in receptor recognition and pore formation. This model will serve as a starting point for the design of mutagenesis experiments aimed to the improvement of toxicity, and to provide a new tool for the elucidation of the mechanism of action of these mosquitocidal proteins.
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Affiliation(s)
- P Gutierrez
- Unidad de Biotecnología y Control Biológico, Corporación para Investigaciones Biológica, Medellin, Colombia
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Aquino de Muro M, Priest FG. Construction of chromosomal integrants of Bacillus sphaericus 2362 by conjugation with Escherichia coli. Res Microbiol 2000; 151:547-55. [PMID: 11037132 DOI: 10.1016/s0923-2508(00)00224-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
IncP-based plasmids conjugated between Escherichia coli and mosquitocidal strains of Bacillus sphaericus at frequencies of 10(-7) to 10(-9) per recipient. Plasmid transfer was most efficient when a restriction-deficient strain of B. sphaericus 2362 (serotype 5a5b) was used as recipient and was least efficient with recipients from serotypes 1a and 2a2b. A deleted version of the cryptic locus 'gene 80' from strain 2362 was cloned into the suicide vector pMTL30, which could not replicate in B. sphaericus to provide a site for chromosomal integration. Conjugational transfer from E. coli and integration into the B. sphaericus recipient chromosome was achieved with this construct. The coding region of the cry11A gene from Bacillus thuringiensis subsp. israelensis was PCR-amplified and fused to the promoter of the crystal protein (Bin) gene of B. sphaericus 2362. This construct was cloned into the integrative vector, conjugated with B. sphaericus 2362 and chromosomal integrants were recovered which harboured the cry11A gene. The fusion gene was efficiently transcribed in the recombinant host, but cells failed to accumulate appreciable amounts of Cry11A toxin. This system offers a simple and efficient means of transferring plasmids into B. sphaericus and obtaining chromosomal integration for strain construction and gene analysis.
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Affiliation(s)
- M Aquino de Muro
- Biosystematics and Molecular Biology, CABI Bioscience UK Centre, Egham, Surrey, UK.
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Escobar E, Segura C, Vanegas M, Patarroyo ME, Orduz S. Proteolytic processing of the Cyt1Ab1 toxin produced by Bacillus thuringiensis subsp. medellin. Mem Inst Oswaldo Cruz 2000; 95:693-700. [PMID: 10998218 DOI: 10.1590/s0074-02762000000500014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bacillus thuringiensis produces d-endotoxins that require proteolytic processing to become active. The activation of the B. thuringiensis subsp. medellin 28 kDa (Cyt1Ab1) cytolytic toxin by trypsin, chymotrypsin and gut extract from Culex quinquefasciatus larvae was analyzed. The Cyt1Ab1 toxin of B. thuringiensis subsp. medellin was processed by all proteases tested to fragments between 23 and 25 kDa, while processing of the Cyt1Aa1 toxin produce fragments between 22.5 and 24.5 kDa. The Cyt1Ab1 toxin was preferentially processed at the alkaline pH of 12. The in vitro proteolytic processing of the Cyt1Ab1 toxin by C. quinquefasciatus larvae midgut extract showed a 25 kDa fragment; a similar result was observed when the activation was performed in the in vivo experiments. The solubilized Cyt1Ab1 toxin and the protease resistant cores generated by in vitro processing showed hemolytic activity but not mosquitocidal activity. Amino terminal sequence of the C. quinquefasciatus gut extract resistant fragment indicated that the cutting site was located between Lys31 and Asp32, with a sequence DDPNEKNNHNS; while for the trypsin-resistant fragment the cutting site was determined between Leu29 and Arg30, and for the chymotrypsin-resistant fragment between Arg30 and Lys31.
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Affiliation(s)
- E Escobar
- Unidad de Biotecnología y Control Biológico, Corporación para Investigaciones Biológicas, Medellín, Colombia
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Wirth MC, Federici BA, Walton WE. Cyt1A from Bacillus thuringiensis synergizes activity of Bacillus sphaericus against Aedes aegypti (Diptera: Culicidae). Appl Environ Microbiol 2000; 66:1093-7. [PMID: 10698776 PMCID: PMC91947 DOI: 10.1128/aem.66.3.1093-1097.2000] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus sphaericus is a mosquitocidal bacterium recently developed as a commercial larvicide that is used worldwide to control pestiferous and vector mosquitoes. Whereas B. sphaericus is highly active against larvae of Culex and Anopheles mosquitoes, it is virtually nontoxic to Aedes aegypti, an important vector species. In the present study, we evaluated the capacity of the cytolytic protein Cyt1A from Bacillus thuringiensis subsp. israelensis to enhance the toxicity of B. sphaericus toward A. aegypti. Various combinations of these two materials were evaluated, and all were highly toxic. A ratio of 10:1 of B. sphaericus to Cyt1A was 3, 600-fold more toxic to A. aegypti than B. sphaericus alone. Statistical analysis showed this high activity was due to synergism between the Cyt1A toxin and B. sphaericus. These results suggest that Cyt1A could be useful in expanding the host range of B. sphaericus.
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Affiliation(s)
- M C Wirth
- Department of Entomology, University of California, Riverside, California 92521, USA.
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Servant P, Rosso ML, Hamon S, Poncet S, Del cluse A, Rapoport G. Production of Cry11A and Cry11Ba toxins in Bacillus sphaericus confers toxicity towards Aedes aegypti and resistant Culex populations. Appl Environ Microbiol 1999; 65:3021-6. [PMID: 10388698 PMCID: PMC91451 DOI: 10.1128/aem.65.7.3021-3026.1999] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cry11A from Bacillus thuringiensis subsp. israelensis and Cry11Ba from Bacillus thuringiensis subsp. jegathesan were introduced, separately and in combination, into the chromosome of Bacillus sphaericus 2297 by in vivo recombination. Two loci on the B. sphaericus chromosome were chosen as target sites for recombination: the binary toxin locus and the gene encoding the 36-kDa protease that may be responsible for the cleavage of the Mtx protein. Disruption of the protease gene did not increase the larvicidal activity of the recombinant strain against Aedes aegypti and Culex pipiens. Synthesis of the Cry11A and Cry11Ba toxins made the recombinant strains toxic to A. aegypti larvae to which the parental strain was not toxic. The strain containing Cry11Ba was more toxic than strains containing the added Cry11A or both Cry11A and Cry11Ba. The production of the two toxins together with the binary toxin did not significantly increase the toxicity of the recombinant strain to susceptible C. pipiens larvae. However, the production of Cry11A and/or Cry11Ba partially overcame the resistance of C. pipiens SPHAE and Culex quinquefasciatus GeoR to B. sphaericus strain 2297.
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Affiliation(s)
- P Servant
- Unité de Biochimie Microbienne, URA 1300 du Centre National de la Recherche Scientifique, Institut Pasteur, 75724 Paris, France.
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