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Xiang SL, Xu KZ, Yin LJ, Jia AQ. An Investigation of Quorum Sensing Inhibitors against Bacillus cereus in The Endophytic Fungus Pithomyces sacchari of the Laurencia sp. Mar Drugs 2024; 22:161. [PMID: 38667778 PMCID: PMC11051030 DOI: 10.3390/md22040161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/28/2024] [Accepted: 03/29/2024] [Indexed: 04/28/2024] Open
Abstract
Bacillus cereus, a common food-borne pathogen, forms biofilms and generates virulence factors through a quorum sensing (QS) mechanism. In this study, six compounds (dankasterone A, demethylincisterol A3, zinnimidine, cyclo-(L-Val-L-Pro), cyclo-(L-Ile-L-Pro), and cyclo-(L-Leu-L-Pro)) were isolated from the endophytic fungus Pithomyces sacchari of the Laurencia sp. in the South China Sea. Among them, demethylincisterol A3, a sterol derivative, exhibited strong QS inhibitory activity against B. cereus. The QS inhibitory activity of demethylincisterol A3 was evaluated through experiments. The minimum inhibitory concentration (MIC) of demethylincisterol A3 against B. cereus was 6.25 μg/mL. At sub-MIC concentrations, it significantly decreased biofilm formation, hindered mobility, and diminished the production of protease and hemolysin activity. Moreover, RT-qPCR results demonstrated that demethylincisterol A3 markedly inhibited the expression of QS-related genes (plcR and papR) in B. cereus. The exposure to demethylincisterol A3 resulted in the downregulation of genes (comER, tasA, rpoN, sinR, codY, nheA, hblD, and cytK) associated with biofilm formation, mobility, and virulence factors. Hence, demethylincisterol A3 is a potentially effective compound in the pipeline of innovative antimicrobial therapies.
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Affiliation(s)
| | | | | | - Ai-Qun Jia
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou 570228, China
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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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The Food Poisoning Toxins of Bacillus cereus. Toxins (Basel) 2021; 13:toxins13020098. [PMID: 33525722 PMCID: PMC7911051 DOI: 10.3390/toxins13020098] [Citation(s) in RCA: 113] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/14/2021] [Accepted: 01/25/2021] [Indexed: 12/13/2022] Open
Abstract
Bacillus cereus is a ubiquitous soil bacterium responsible for two types of food-associated gastrointestinal diseases. While the emetic type, a food intoxication, manifests in nausea and vomiting, food infections with enteropathogenic strains cause diarrhea and abdominal pain. Causative toxins are the cyclic dodecadepsipeptide cereulide, and the proteinaceous enterotoxins hemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe) and cytotoxin K (CytK), respectively. This review covers the current knowledge on distribution and genetic organization of the toxin genes, as well as mechanisms of enterotoxin gene regulation and toxin secretion. In this context, the exceptionally high variability of toxin production between single strains is highlighted. In addition, the mode of action of the pore-forming enterotoxins and their effect on target cells is described in detail. The main focus of this review are the two tripartite enterotoxin complexes Hbl and Nhe, but the latest findings on cereulide and CytK are also presented, as well as methods for toxin detection, and the contribution of further putative virulence factors to the diarrheal disease.
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Zamyatina AV, Rudenko NV, Karatovskaya AP, Shepelyakovskaya AO, Siunov AV, Andreeva-Kovalevskaya ZI, Nagel AS, Salyamov VI, Kolesnikov AS, Brovko FA, Solonin AS. Monoclonal Antibody HlyIIC‑15 to C-End Domain HlyII B. cereus Interacts with the Trombin Recognition Site. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020; 46:1214-1220. [PMID: 33390685 PMCID: PMC7768993 DOI: 10.1134/s1068162020060382] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 11/23/2022]
Abstract
Among the panel of monoclonal antibodies to the recombinant protein HlyIICTD Bacillus cereus an antibody was found capable of forming an immune complex with a thrombin recognition region, the amino acid sequence of which is located inside the recombinant HlyIICTD. Localization of the epitope was carried out using peptide phage display methods, as well as enzyme immunoassay and immunoblotting for interaction with recombinant proteins, either containing or not containing individual components HlyIICTD. The identified epitope is located in the region of the thrombin site and retains the ability to interact with the antibody after the proteolyotic attack of the protein by thrombin.
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Affiliation(s)
- A. V. Zamyatina
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
- Pushchino State Natural Science Institute, Pushchino, Moscow oblast 142290 Russia
| | - N. V. Rudenko
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - A. P. Karatovskaya
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - A. O. Shepelyakovskaya
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - A. V. Siunov
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - Zh. I. Andreeva-Kovalevskaya
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - A. S. Nagel
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - V. I. Salyamov
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - A. S. Kolesnikov
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - F. A. Brovko
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
- Pushchino State Natural Science Institute, Pushchino, Moscow oblast 142290 Russia
| | - A. S. Solonin
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
- Pushchino State Natural Science Institute, Pushchino, Moscow oblast 142290 Russia
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McBrayer DN, Cameron CD, Tal-Gan Y. Development and utilization of peptide-based quorum sensing modulators in Gram-positive bacteria. Org Biomol Chem 2020; 18:7273-7290. [PMID: 32914160 PMCID: PMC7530124 DOI: 10.1039/d0ob01421d] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Quorum sensing (QS) is a mechanism by which bacteria regulate cell density-dependent group behaviors. Gram-positive bacteria generally rely on auto-inducing peptide (AIP)-based QS signaling to regulate their group behaviors. To develop synthetic modulators of these behaviors, the natural peptide needs to be identified and its structure-activity relationships (SARs) with its cognate receptor (either membrane-bound or cytosolic) need to be understood. SAR information allows for the rational design of peptides or peptide mimics with enhanced characteristics, which in turn can be utilized in studies to understand species-specific QS mechanisms and as lead scaffolds for the development of therapeutic candidates that target QS. In this review, we discuss recent work associated with the approaches used towards forwarding each of these steps in Gram-positive bacteria, with a focus on species that have received less attention.
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Affiliation(s)
- Dominic N McBrayer
- Department of Chemistry, SUNY New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA. and Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV 89557, USA.
| | - Crissey D Cameron
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV 89557, USA.
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV 89557, USA.
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Rap-Phr Systems from Plasmids pAW63 and pHT8-1 Act Together To Regulate Sporulation in the Bacillus thuringiensis Serovar kurstaki HD73 Strain. Appl Environ Microbiol 2020; 86:AEM.01238-20. [PMID: 32680861 DOI: 10.1128/aem.01238-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 07/13/2020] [Indexed: 02/07/2023] Open
Abstract
Bacillus thuringiensis is a Gram-positive spore-forming bacterium pathogenic to various insect species. This property is due to the Cry toxins encoded by plasmid genes and mostly produced during sporulation. B. thuringiensis contains a remarkable number of extrachromosomal DNA molecules and a great number of plasmid rap-phr genes. Rap-Phr quorum-sensing systems regulate different bacterial processes, notably the commitment to sporulation in Bacillus species. Rap proteins are quorum sensors acting as phosphatases on Spo0F, an intermediate of the sporulation phosphorelay, and are inhibited by Phr peptides that function as signaling molecules. In this study, we characterize the Rap63-Phr63 system encoded by the pAW63 plasmid from the B. thuringiensis serovar kurstaki HD73 strain. Rap63 has moderate activity on sporulation and is inhibited by the Phr63 peptide. The rap63-phr63 genes are cotranscribed, and the phr63 gene is also transcribed from a σH-specific promoter. We show that Rap63-Phr63 regulates sporulation together with the Rap8-Phr8 system harbored by plasmid pHT8_1 of the HD73 strain. Interestingly, the deletion of both phr63 and phr8 genes in the same strain has a greater negative effect on sporulation than the sum of the loss of each phr gene. Despite the similarities in the Phr8 and Phr63 sequences, there is no cross talk between the two systems. Our results suggest a synergism of these two Rap-Phr systems in the regulation of the sporulation of B. thuringiensis at the end of the infectious cycle in insects, thus pointing out the roles of the plasmids in the fitness of the bacterium.IMPORTANCE The life cycle of Bacillus thuringiensis in insect larvae is regulated by quorum-sensing systems of the RNPP family. After the toxemia caused by Cry insecticidal toxins, the sequential activation of these systems allows the bacterium to trigger first a state of virulence (regulated by PlcR-PapR) and then a necrotrophic lifestyle (regulated by NprR-NprX); ultimately, sporulation is controlled by the Rap-Phr systems. Our study describes a new rap-phr operon carried by a B. thuringiensis plasmid and shows that the Rap protein has a moderate effect on sporulation. However, this system, in combination with another plasmidic rap-phr operon, provides effective control of sporulation when the bacteria develop in the cadavers of infected insect larvae. Overall, this study highlights the important adaptive role of the plasmid Rap-Phr systems in the developmental fate of B. thuringiensis and its survival within its ecological niche.
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Thomas GH. Microbial musings – April 2020. Microbiology (Reading) 2020; 166:332-334. [PMID: 32553068 PMCID: PMC7376259 DOI: 10.1099/mic.0.000925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Gavin H. Thomas
- Department of Biology, University of York, York, YO10 5YW, UK
- *Correspondence: Gavin H. Thomas,
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