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Peña-Rico MA, Bravo-D HR, Roldan-Sabino C, Castro-Cerritos KV, Huerta-Heredia A, Navarro-Mtz AK. Addition of proteinase K during the culture alter the physiology of Bacillus thuringiensis culture and the cry1Ac, nprX, nprA, and spo0A gene transcription. Antonie van Leeuwenhoek 2021; 115:89-102. [PMID: 34797466 DOI: 10.1007/s10482-021-01683-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 11/03/2021] [Indexed: 11/30/2022]
Abstract
Bacillus thuringiensis is the major bioinsecticide worldwide produced due to the Cry protein activity. Several studies have been done to improve the cost-productivity relation. The neutral protease A (NprA) is the major extracellular protein massively produced during the stationary phase by this bacterium, contributing to the Cry proteins' degradation. Also, the deletion of aprA and nprA genes enhanced the yield of Cry protein, stabilizing it. Therefore, to increase Cry production, one possibility is to degrade the NprA protease in the culture media. In the present study, proteinase K was used to hydrolyze the NprA to increase Cry production. Proteinase K was added during the exponential growth of B. thuringiensis culture. The bacilli and endospores were measured along all culture, while the Cry protein was measured at the end of the culture. The addition of PK affects the bacilli and spore kinetics positively but negatively to the Cry protein (there is no Cry protein detection). Therefore, the gene expression of the cry1Ac, nprX, nprA, and spo0A was measured. The expression of each gene was followed along all culture. Results demonstrated that PK alters both the transcriptional levels and the expression order of the genes.
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Affiliation(s)
- Miguel A Peña-Rico
- Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Humberto R Bravo-D
- División de Estudios de Posgrado, Doctorado en Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Crisanto Roldan-Sabino
- Ingeniería en Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Karla V Castro-Cerritos
- Instituto de Química Aplicada, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - Ariana Huerta-Heredia
- Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México.,CONACyT-UNPA, Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México
| | - A Karin Navarro-Mtz
- Instituto de Biotecnología, Universidad del Papaloapan, Circuito Central 200, Parque Industrial, 68301, Tuxtepec, Oaxaca, México.
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Elleuch J, Zghal RZ, Ben Fguira I, Lacroix MN, Suissi J, Chandre F, Tounsi S, Jaoua S. Effects of the P20 protein from Bacillus thuringiensis israelensis on insecticidal crystal protein Cry4Ba. Int J Biol Macromol 2015; 79:174-9. [DOI: 10.1016/j.ijbiomac.2015.04.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/08/2015] [Accepted: 04/09/2015] [Indexed: 11/25/2022]
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Pacheco-Cano RD, de la Fuente-Salcido NM, Salcedo-Hernández R, León-Galván MF, Bideshi DK, Hernández-Guzmán G, Barboza-Corona JE. Characterization, N-terminal sequencing and classification of Tolworthcin 524: A bacteriocin produced by Bacillus thuringiensis subsp. tolworthi. Microbiol Res 2014; 169:948-53. [DOI: 10.1016/j.micres.2014.04.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 04/11/2014] [Accepted: 04/29/2014] [Indexed: 10/25/2022]
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Cytolytic peptide fragments of Cyt1Aa from Bacillus thuringiensis subsp. israelensis. Cell Biochem Biophys 2012; 65:121-7. [PMID: 22875467 DOI: 10.1007/s12013-012-9405-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Cyt1Aa is the major and most active component of the parasporal crystal of the Gram-positive soil entomopathogenic bacterium Bacillus thuringiensis subsp. israelensis. The Cyt1Aa protoxin exhibits some hemolytic and cytolytic activity. However, highly active 22-25 kDa toxins are obtained after proteolysis of Cyt1Aa from both the N- and the C-termini. As shown in this study, preliminary binding of the protoxin to polylamellary liposomes or partial denaturation of Cyt1Aa and further processing by several exogenous proteases yielded short 4.9-11.5 kDa cytolytic peptide fragments of Cyt1Aa. The shortest 51 amino acid peptide was obtained after pre-incubation of Cyt1Aa with SDS and proteolysis with proteinase K. This peptide was purified, identified as the Ile87-Asp137 fragment of Cyt1Aa and was shown to exhibit more than 30 % hemolysis of rabbit erythrocytes.
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Perchat S, Dubois T, Zouhir S, Gominet M, Poncet S, Lemy C, Aumont-Nicaise M, Deutscher J, Gohar M, Nessler S, Lereclus D. A cell-cell communication system regulates protease production during sporulation in bacteria of the Bacillus cereus group. Mol Microbiol 2011; 82:619-33. [PMID: 21958299 DOI: 10.1111/j.1365-2958.2011.07839.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In sporulating Bacillus, major processes like virulence gene expression and sporulation are regulated by communication systems involving signalling peptides and regulators of the RNPP family. We investigated the role of one such regulator, NprR, in bacteria of the Bacillus cereus group. We show that NprR is a transcriptional regulator whose activity depends on the NprX signalling peptide. In association with NprX, NprR activates the transcription of an extracellular protease gene (nprA) during the first stage of the sporulation process. The transcription start site of the nprA gene has been identified and the minimal region necessary for full activation has been characterized by promoter mutagenesis. We demonstrate that the NprX peptide is secreted, processed and then reimported within the bacterial cell. Once inside the cell, the mature form of NprX, presumably the SKPDIVG heptapeptide, directly binds to NprR allowing nprA transcription. Alignment of available NprR sequences from different species of the B. cereus group defines seven NprR clusters associated with seven NprX heptapeptide classes. This cell-cell communication system was found to be strain-specific with a possible cross-talk between some pherotypes. The phylogenic relationship between NprR and NprX suggests a coevolution of the regulatory protein and its signalling peptide.
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Rocha-Estrada J, Aceves-Diez AE, Guarneros G, de la Torre M. The RNPP family of quorum-sensing proteins in Gram-positive bacteria. Appl Microbiol Biotechnol 2010; 87:913-23. [PMID: 20502894 DOI: 10.1007/s00253-010-2651-y] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 03/29/2010] [Accepted: 04/20/2010] [Indexed: 11/29/2022]
Abstract
Quorum sensing is one of several mechanisms that bacterial cells use to interact with each other and coordinate certain physiological processes in response to cell density. This mechanism is mediated by extracellular signaling molecules; once a critical threshold concentration has been reached, a target sensor kinase or response regulator is activated (or repressed), facilitating the expression of quorum sensing-dependent genes. Gram-positive bacteria mostly use oligo-peptides as signaling molecules. These cells have a special kind of quorum-sensing systems in which the receptor protein interacts directly with its cognate signaling peptide. The receptors are either Rap phosphatases or transcriptional regulators and integrate the protein family RNPP, from Rap, Npr, PlcR, and PrgX. These quorum-sensing systems control several microbial processes, like sporulation, virulence, biofilm formation, conjugation, and production of extracellular enzymes. Insights of the mechanism of protein-signaling peptide binding as well as the molecular interaction among receptor protein, signaling peptide, and target DNA have changed some earlier perceptions. In spite of the increased knowledge and the potential biotechnological applications of these quorum-sensing systems, few examples on engineering for biotechnological applications have been published. Real applications will arise only when researchers working in applied microbiology and biotechnology are aware of the importance of quorum-sensing systems for health and bioprocess applications.
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Affiliation(s)
- Jorge Rocha-Estrada
- Centro de Investigación en Alimentación y Desarrollo, A. C., Carretera a la Victoria Km. 0.6, 83304, Hermosillo, Sonora, México
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Nisnevitch M, Sigawi S, Cahan R, Nitzan Y. Isolation, characterization and biological role of camelysin from Bacillus thuringiensis subsp. israelensis. Curr Microbiol 2010; 61:176-83. [PMID: 20127334 DOI: 10.1007/s00284-010-9593-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 01/18/2010] [Indexed: 10/19/2022]
Abstract
The present study reports a simple rapid method for isolating the zinc-containing metalloprotease camelysin from Bacillus thuringiensis subsp. israelensis (Bti) by extraction from intact bacterial cells with egg L-alpha-phosphatidylcholine containing monolamellar liposomes, followed by separation on a sucrose gradient. Characterization of the isolated camelysin revealed a molecular weight of 23 kDa and a pI of 6.2. The camelysin exhibited maximal activity against the substrate azocasein at a temperature of 37 degrees C and pH 7.5. However, the enzyme's activity remained high also at basic pH values (8-10). In a rich growth medium (LB), camelysin appeared at the late logarithmic phase of Bti growth and reached its maximum in the stationary phase. Camelysin was shown to activate the protoxins Cyt1Aa and Cyt2Ba produced by Bti. The hemolytic activity of Cyt1Aa increased from 40 to 70% and that of Cyt2Ba from 6 to 50% in the presence of 50% (w/w) camelysin. It is concluded that these protoxins can be activated not only by insect gut proteases, but also by the endogeneous metalloprotease camelysin of the Bti bacterium.
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Affiliation(s)
- Marina Nisnevitch
- Department of Chemical Engineering and Biotechnology, Ariel University Center of Samaria, Ariel 44837, Israel.
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Batch and fed-batch fermentation of Bacillus thuringiensis using starch industry wastewater as fermentation substrate. Bioprocess Biosyst Eng 2009; 33:691-700. [PMID: 19888605 DOI: 10.1007/s00449-009-0391-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Accepted: 10/16/2009] [Indexed: 10/20/2022]
Abstract
Bacillus thuringiensis var. kurstaki biopesticide was produced in batch and fed-batch fermentation modes using starch industry wastewater as sole substrate. Fed-batch fermentation with two intermittent feeds (at 10 and 20 h) during the fermentation of 72 h gave the maximum delta-endotoxin concentration (1,672.6 mg/L) and entomotoxicity (Tx) (18.5 x 10(6) SBU/mL) in fermented broth which were significantly higher than maximum delta-endotoxin concentration (511.0 mg/L) and Tx (15.8 x 10(6) SBU/mL) obtained in batch process. However, fed-batch fermentation with three intermittent feeds (at 10, 20 and 34 h) of the fermentation resulted in the formation of asporogenous variant (Spo-) from 36 h to the end of fermentation (72 h) which resulted in a significant decrease in spore and delta-endotoxin concentration and finally the Tx value. Tx of suspended pellets (27.4 x 10(6) SBU/mL) obtained in fed-batch fermentation with two feeds was the highest value as compared to other cases.
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Freilich S, Kreimer A, Borenstein E, Yosef N, Sharan R, Gophna U, Ruppin E. Metabolic-network-driven analysis of bacterial ecological strategies. Genome Biol 2009; 10:R61. [PMID: 19500338 PMCID: PMC2718495 DOI: 10.1186/gb-2009-10-6-r61] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 05/06/2009] [Accepted: 06/05/2009] [Indexed: 11/10/2022] Open
Abstract
Bacterial ecological strategies revealed by metabolic network analysis show that ecological diversity correlates with metabolic flexibility, faster growth rate and intense co-habitation. Background The growth-rate of an organism is an important phenotypic trait, directly affecting its ability to survive in a given environment. Here we present the first large scale computational study of the association between ecological strategies and growth rate across 113 bacterial species, occupying a variety of metabolic habitats. Genomic data are used to reconstruct the species' metabolic networks and habitable metabolic environments. These reconstructions are then used to investigate the typical ecological strategies taken by organisms in terms of two basic species-specific measures: metabolic variability - the ability of a species to survive in a variety of different environments; and co-habitation score vector - the distribution of other species that co-inhabit each environment. Results We find that growth rate is significantly correlated with metabolic variability and the level of co-habitation (that is, competition) encountered by an organism. Most bacterial organisms adopt one of two main ecological strategies: a specialized niche with little co-habitation, associated with a typically slow rate of growth; or ecological diversity with intense co-habitation, associated with a typically fast rate of growth. Conclusions The pattern observed suggests a universal principle where metabolic flexibility is associated with a need to grow fast, possibly in the face of competition. This new ability to produce a quantitative description of the growth rate-metabolism-community relationship lays a computational foundation for the study of a variety of aspects of the communal metabolic life.
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Affiliation(s)
- Shiri Freilich
- The Blavatnik School of Computer Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.
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Impact of different pH control agents on biopesticidal activity of Bacillus thuringiensis during the fermentation of starch industry wastewater. Bioprocess Biosyst Eng 2008; 32:511-9. [DOI: 10.1007/s00449-008-0271-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 10/07/2008] [Indexed: 11/27/2022]
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11
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Cahan R, Friman H, Nitzan Y. Antibacterial activity of Cyt1Aa from Bacillus thuringiensis subsp. israelensis. Microbiology (Reading) 2008; 154:3529-3536. [DOI: 10.1099/mic.0.2008/020784-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Rivka Cahan
- Department of Chemical Engineering and Biotechnology, Ariel University Center of Samaria, Ariel 44837, Israel
| | - Hen Friman
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel
- Department of Chemical Engineering and Biotechnology, Ariel University Center of Samaria, Ariel 44837, Israel
| | - Yeshayahu Nitzan
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel
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Cahan R, Hetzroni E, Nisnevitch M, Nitzan Y. Purification and identification of a novel leucine aminopeptidase from Bacillus thuringiensis israelensis. Curr Microbiol 2007; 55:413-9. [PMID: 17682820 DOI: 10.1007/s00284-007-9004-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Accepted: 05/20/2007] [Indexed: 11/25/2022]
Abstract
A novel leucine aminopeptidase was purified from a Bacillus thuringiensis israelensis (Bti) culture. The purification stages included heating the concentrated supernatant to 65 degrees C for 90 min, anion-exchange chromatography by DEAE cellulose, and hydrophobic chromatography by phenyl Sepharose. The specific activity of leucine aminopeptidase after the hydrophobic chromatography increased by 215.5-fold and the yield was 16%. The molecular weight of the active enzyme was 59 kDa. Mass spectrometry analysis of the 59-kDa leucine aminopeptidase revealed that this protein has at least 41% homology with the cytosol leucine aminopeptidase produced by Bacillus cereus. Maximal leucine aminopeptidase activity occurred at 65 degrees C, pH 10 toward leucine as the amino acid terminus. The enzyme was strongly inhibited by bestatin, dithiothreitol, and 1,10-phenanthroline, indicating that the enzyme might be considered as a metallo-aminopeptidase that has disulfide bonds at the catalytic site or at a region that influences its configuration. Examination of the purified leucine aminopeptidase's effect on the activation of the protoxin Cyt1Aa from Bti revealed that when it acts synergistically with Bti endogenous proteases, it has only a minor role in the processing of Cyt1Aa into an active toxin.
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Affiliation(s)
- Rivka Cahan
- Department of Chemical Engineering and Biotechnology, College of Judea and Samaria, Ariel 44837, Israel.
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Nisnevitch M, Cohen S, Ben-Dov E, Zaritsky A, Sofer Y, Cahan R. Cyt2Ba of Bacillus thuringiensis israelensis: activation by putative endogenous protease. Biochem Biophys Res Commun 2006; 344:99-105. [PMID: 16630537 DOI: 10.1016/j.bbrc.2006.03.134] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Accepted: 03/20/2006] [Indexed: 10/24/2022]
Abstract
The gene cyt2Ba of Bacillus thuringiensis subsp. israelensis was cloned for expression, together with p20, in an acrystalliferous strain. The large hexagonal crystals formed were composed of Cyt2Ba, which facilitated its purification. Crystal solubilization in the presence of endogenous proteases (with spores and cell debris) enabled quick and simple procedure to obtain rather pure and active toxin species by cleavage between amino acid residues 34 and 35, most likely by a camelysin-like protease that was discovered in association with activated Cyt2Ba. The product of this cleavage displayed haemolytic activity comparable to that of exogenously activated Cyt2Ba. The sequence of this putative protease shares high homology with the cell envelope-bound metalloprotease (camelysin) of the closely related species Bacillus cereus.
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Affiliation(s)
- Marina Nisnevitch
- Department of Chemical Engineering and Biotechnology, College of Judea and Samaria, Ariel 44837, Israel
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Brar SK, Verma M, Tyagi RD, Valéro JR, Surampalli RY. Efficient centrifugal recovery of Bacillus thuringiensis biopesticides from fermented wastewater and wastewater sludge. WATER RESEARCH 2006; 40:1310-20. [PMID: 16515801 DOI: 10.1016/j.watres.2006.01.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Revised: 11/27/2005] [Accepted: 01/21/2006] [Indexed: 05/06/2023]
Abstract
Studies were conducted on harvesting of Bacillus thuringiensis (Bt)-based biopesticides from fermented broths of starch industry wastewater (SIW), wastewater sludge (raw and hydrolyzed-NH and TH, respectively) and semi-synthetic soyameal to enhance entomotoxicity (Tx) by centrifugation. Pertinent factors influencing Tx, solids concentration, pH, temperature and centrifugal force were investigated. The centrifugate solids concentration beyond 100 g/l did not enhance Tx, instead caused pellet formation. Centrifugation efficiency (Tx recovery) was higher at pH 4, and temperature 20 degrees C for starch wastewater (98%), wastewater sludge (98% and 97.8% for non-hydrolyzed and hydrolyzed, respectively) and soya broth (83%). For maximum Tx recovery (SIW-95%; NH-90%; TH-98% and soya-78%), the centrifugal force and time required was 48,000 g and 30 min, respectively. Losses in recovery efficiency were lower for SIW and wastewater sludge in comparison to soya on adopting commercially recommended centrifugal force of 9000 g. The settling velocity computations for different fermented broths enabled calculation of Sigma factor for continuous commercial centrifuge of a given capacity and hence simulation of power requirements. It was established that power requirements for a given Tx recovery efficiency were highest for conventional medium (soya) in comparison to other waste-based fermented broths.
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Affiliation(s)
- Satinder K Brar
- INRS-ETE, Université du Québec, 490, Rue de la Couronne, Quebec, Canada G1K 9A9
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Ghorbel-Frikha B, Sellami-Kamoun A, Fakhfakh N, Haddar A, Manni L, Nasri M. Production and purification of a calcium-dependent protease from Bacillus cereus BG1. J Ind Microbiol Biotechnol 2005; 32:186-94. [PMID: 15843974 DOI: 10.1007/s10295-005-0228-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Accepted: 03/18/2005] [Indexed: 10/25/2022]
Abstract
The production and purification of a calcium-dependent protease by Bacillus cereus BG1 were studied. The production of the protease was found to depend specifically on the calcium concentration in the culture medium. This suggests that this metal ion is essential for the induction of protease production and/or stabilisation of the enzyme after synthesis. The calcium requirement is highly specific since other metal ions (such as Mg(2+) and Ba(2+), which both activate the enzyme) are not able to induce protease production. The most appropriate medium for growth and protease production comprises (g L(-1)) starch 5, CaCl(2) 2, yeast extract 2, K(2)HPO(4) 0.2 and KH(2)PO(4) 0.2. The protease of BG1 strain was purified to homogeneity by ultrafiltration, heat treatment, gel filtration on Sephacryl S-200, ion exchange chromatography on DEAE-cellulose and, finally, a second gel filtration on Sephacryl S-200, with a 39-fold increase in specific activity and 23% recovery. The molecular weight was estimated to be 34 kDa on SDS-PAGE. The optimum temperature and pH of the purified enzyme were determined to be 60 degrees C and 8.0, respectively, in 100 mM Tris-HCl buffer + 2 mM CaCl(2).
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Affiliation(s)
- B Ghorbel-Frikha
- Laboratoire de Génie Enzymatique et de Microbiologie, Ecole Nationale d'Ingénieurs de Sfax, Tunisia
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Shao Z, Liu Z, Yu Z. Effects of the 20-kilodalton helper protein on Cry1Ac production and spore formation in Bacillus thuringiensis. Appl Environ Microbiol 2001; 67:5362-9. [PMID: 11722880 PMCID: PMC93317 DOI: 10.1128/aem.67.12.5362-5369.2001] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus thuringiensis produces large amounts of various pesticidal proteins during the stationary phase. In order to achieve a high yield and form crystals, some pesticidal proteins require the presence of other proteins. Helper protein P20 is required for efficient production of both the Cyt1A and Cry11A crystal proteins in B. thuringiensis subsp. israelensis. Although full-length Cry1 protoxins are usually independent in terms of expression and crystallization in B. thuringiensis, in this study P20 significantly enhanced production of Cry1Ac protoxin (133 kDa) in an acrystalliferous and plasmid-negative strain. In the presence of P20, the yield of Cry1Ac protoxin increased 2.5-fold, and on average the resulting crystals were 1.85 microm long and 0.85 microm wide, three times the size of the crystals formed in the control lacking P20. Correspondingly, the recombinant strain that coexpressed P20 and Cry1Ac exhibited higher toxicity against Heliothis armigera larvae than the control. Furthermore, serious degradation of Cry1Ac in vivo was observed, which has seldom been reported previously. Actually, most protein was completely degraded during synthesis, and after synthesis about one-third of the expressed protoxins were degraded further before crystallization. In this process, P20 protected only nascent Cry1Ac from degradation, indicating that it acted as a molecular chaperon. In addition, spores were smaller and rounder and had a thinner exosporium layer when they were produced in the presence of P20. In summary, Cry1Ac was severely degraded during synthesis; this degradation was effectively relieved by P20, which resulted in enhanced production. Our results indicated that P20 is an effective tool for optimizing protein production in vivo.
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Affiliation(s)
- Z Shao
- Life Science and Technology College, Huazhong Agricultural University, Wuhan 430070, Hubei, People's Republic of China
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18
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Tan Y, Donovan WP. Deletion of aprA and nprA genes for alkaline protease A and neutral protease A from bacillus thuringiensis: effect on insecticidal crystal proteins. J Biotechnol 2001; 84:67-72. [PMID: 11035189 DOI: 10.1016/s0168-1656(00)00328-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The aprA gene encoding alkaline protease A (AprA) was cloned from Bacillus thuringiensis subsp. kurstaki, and the cloned gene was used to construct aprA-deleted (aprA1) strains of B. thuringiensis. An aprA1 strain of B. thuringiensis that contained the wild-type gene for neutral protease A (nprA(+)) displayed levels of extracellular proteolytic activity that were similar to those of an aprA(+)nprA(+) strain. However, when EDTA was included in the protease assay to inhibit NprA activity the aprA1nprA(+) strain displayed only 2% of the extracellular proteolytic activity of the aprA(+)nprA(+) strain. A strain that was deleted for both aprA and nprA (aprA1nprA3 strain) failed to produce detectable levels of proteolytic activity either in the presence or absence of EDTA in the assay. Compared with the aprA(+)nprA(+) strain the aprA1nprA(+) strain yielded 10% more full-length Cry1Bb crystal protein and the aprA1nprA3 strain yielded 25% more full-length Cry1Bb protein. No significant differences were seen in the 50% lethal dose of Cry1Bb protein from aprA(+)nprA(+) and aprA1nprA3 strains against three species of lepidopteran insects. These results suggest that enhanced yield of certain crystal proteins can be obtained by deletion of the genes aprA and nprA which are the major extracellular proteases of B. thuringiensis.
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Affiliation(s)
- Y Tan
- Ecogen, Inc., 2000 Cabot Boulevard West, Langhorne, Pennsylvania, PA 19047, USA
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19
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Production and characterization of metalloproteases synthesized concomitantly with δ-endotoxin by Bacillus thuringiensis subsp. kurstaki strain grown on gruel-based media. Enzyme Microb Technol 1999. [DOI: 10.1016/s0141-0229(99)00054-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bach H, Errampalli D, Leung KT, Lee H, Hartmann A, Trevors JT, Munch JC. Specific detection of the gene for the extracellular neutral protease of Bacillus cereus by PCR and blot hybridization. Appl Environ Microbiol 1999; 65:3226-8. [PMID: 10388725 PMCID: PMC91478 DOI: 10.1128/aem.65.7.3226-3228.1999] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A pair of primers and a gene probe for the amplification and detection of the Bacillus cereus neutral protease gene (NPRC) were developed. Specificity for the npr genes of the B. cereus group members B. cereus, B. mycoides, and B. thuringiensis was shown. Restriction polymorphism patterns of the PCR products confirmed the presence of the NPRC gene in all three species.
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Affiliation(s)
- H Bach
- Institute for Soil Ecology, GSF-National Research Center for Environment and Health, 85764 Neuherberg, Germany.
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Schnepf E, Crickmore N, Van Rie J, Lereclus D, Baum J, Feitelson J, Zeigler DR, Dean DH. Bacillus thuringiensis and its pesticidal crystal proteins. Microbiol Mol Biol Rev 1998; 62:775-806. [PMID: 9729609 PMCID: PMC98934 DOI: 10.1128/mmbr.62.3.775-806.1998] [Citation(s) in RCA: 1690] [Impact Index Per Article: 65.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During the past decade the pesticidal bacterium Bacillus thuringiensis has been the subject of intensive research. These efforts have yielded considerable data about the complex relationships between the structure, mechanism of action, and genetics of the organism's pesticidal crystal proteins, and a coherent picture of these relationships is beginning to emerge. Other studies have focused on the ecological role of the B. thuringiensis crystal proteins, their performance in agricultural and other natural settings, and the evolution of resistance mechanisms in target pests. Armed with this knowledge base and with the tools of modern biotechnology, researchers are now reporting promising results in engineering more-useful toxins and formulations, in creating transgenic plants that express pesticidal activity, and in constructing integrated management strategies to insure that these products are utilized with maximum efficiency and benefit.
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Affiliation(s)
- E Schnepf
- Mycogen Corp., San Diego, California 92121, USA
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