1
|
Tuan Nguyen P, Restaino L. Isolation and Enumeration of the Bacillus cereus Group Using a Chromogenic Substrate that Targets Phosphatidylcholine Phospholipase C Activity. J Food Prot 2024:100376. [PMID: 39393642 DOI: 10.1016/j.jfp.2024.100376] [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: 07/05/2024] [Revised: 10/03/2024] [Accepted: 10/04/2024] [Indexed: 10/13/2024]
Abstract
The Bacillus cereus group is comprised of diverse yet closely-related species that are ubiquitous in nature. These Gram-positive, spore-forming bacteria are commonly isolated as potential pathogens in environmental and food samples, and they are also beneficially used in industrial applications such as probiotics or agricultural pesticides. Although phylogenetic and genomic analyses identified eight formally recognized species within the Bacillus cereus group, only five members are currently acknowledged using standardized isolation procedures. Therefore, current enumeration procedures may be inadequate and inaccurate in determining the clinical importance of the B. cereus group and their prevalence in food and environmental sources. In this investigation, the R & F® Bacillus cereus Group Chromogenic Plating Medium (BCG) was developed to target the enzyme phosphatidylcholine phospholipase C (PC-PLC) found widely distributed among the B. cereus group species. The performance evaluations of the plating medium demonstrated 100% plating productivity ratio, inclusivity, and exclusivity when compared with Trypto Soy Agar (TSA). B. cereus group species, including B. anthracis, B. cereus sensu stricto (s.s.), B. cytotoxicus, B. pseudomycoides, B. mycoides, B. thuringiensis, B. toyonensis, B. weidmannii, and B. weihenstephanensis, formed turquoise-colored colonies on the BCG agar, indicating PC-PLC activity after 24-28 hour of incubation at the selected optimal temperature of 35°C. Furthermore, no significant difference was observed between BCG and TSA when enumerating B. cereus s.s. and B. cytotoxicus artificially inoculated in whey protein powder and ultra-high temperature milk after long-term storage.
Collapse
Affiliation(s)
- Paul Tuan Nguyen
- R & F Products, Inc., 2725 Curtiss Street, Downers Grove, IL 60515, USA.
| | - Lawrence Restaino
- R & F Products, Inc., 2725 Curtiss Street, Downers Grove, IL 60515, USA
| |
Collapse
|
2
|
Dos Santos Mascarenhas LR, Vivoni AM, Caetano RG, Rusak LA, Alvarenga VO, Lacerda ICA. Molecular characterization and toxigenic profiles of Bacillus cereus isolates from foodstuff and food poisoning outbreaks in Brazil. Braz J Microbiol 2024; 55:1693-1701. [PMID: 38446406 PMCID: PMC11153380 DOI: 10.1007/s42770-024-01283-4] [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: 06/13/2023] [Accepted: 02/07/2024] [Indexed: 03/07/2024] Open
Abstract
Bacillus cereus sensu stricto (s.s.) is a well-known foodborne pathogen that produces a range of enterotoxins and is able to cause two different types of foodborne illnesses-the emetic and the diarrheal syndromes. In this study, 54 B. cereus s.s. strains isolated from foodstuff and foods involved in food poisoning outbreaks were characterized according to the presence of toxin-encoding genes, virulence-encoding genes, and panC typing. Most isolates were assigned to panC groups IV (61.1%) and III (25.9%), but members of groups II and V could also be found. Investigation of specific alleles revealed high numbers of isolates carrying toxin and other virulence genes including nheA (100%), nheB (100%), hblA (79.6%), hblC (79.6%), hblD (74.1%), cytK-2 (61.1%), clo (100%), pc-plc (75.9%), sph (68.5%), pi-plc (66.6%), hlyIII (62.9%), and hlyII (24.1%). All isolates were negative for ces and cytK-1. In summary, we detected various enterotoxin and other virulence factor genes associated with diarrheal syndrome in strains analyzed, implicated or not with food poisoning. Furthermore, the most isolates analyzed belong to high-risk phylogenetic groups' panC types III and IV. Our study provides a convenient molecular scheme for characterization of B. cereus s.s. strains responsible for food poisoning outbreaks in order to improve the monitoring and investigation and assess emerging clusters and diversity of strains.
Collapse
Affiliation(s)
- Luís Renato Dos Santos Mascarenhas
- Food Microbiology Laboratory, Ezequiel Dias Foundation, Belo Horizonte/MG, Brazil.
- Department of Food, Faculty of Pharmacy, Federal University of Minas Gerais, Belo Horizonte/MG, Brazil.
| | | | - Renata Gomes Caetano
- Department of Food, Faculty of Pharmacy, Federal University of Minas Gerais, Belo Horizonte/MG, Brazil
| | - Leonardo Alves Rusak
- Bacterial Physiology Laboratory, Oswaldo Cruz Foundation, Rio de Janeiro/RJ, Brazil
| | - Verônica Ortiz Alvarenga
- Department of Food, Faculty of Pharmacy, Federal University of Minas Gerais, Belo Horizonte/MG, Brazil
| | | |
Collapse
|
3
|
Forrest S, Ton S, Sholes SL, Harrison S, Plaut RD, Verratti K, Wittekind M, Ettehadieh E, Necciai B, Sozhamannan S, Grady SL. Genetic evidence for the interaction between Bacillus anthracis-encoded phage receptors and their cognate phage-encoded receptor binding proteins. Front Microbiol 2023; 14:1278791. [PMID: 38029077 PMCID: PMC10644760 DOI: 10.3389/fmicb.2023.1278791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023] Open
Abstract
Bacteriophages such as γ and AP50c have been shown to infect strains of Bacillus anthracis with high specificity, and this feature has been exploited in the development of bacterial detection assays. To better understand the emergence of phage resistance, and thus the potential failure of such assays, it is important to identify the host and phage receptors necessary for attachment and entry. Using genetic approaches, the bacterial receptors of AP50c and γ have been identified as sap and GamR, respectively. A second AP50c-like phage, Wip1, also appears to use sap as a receptor. In parallel with this work, the cognate phage-encoded receptor binding proteins (RBPs) have also been identified (Gp14 for γ, P28 for AP50c, and P23 for Wip1); however, the strength of evidence supporting these protein-protein interactions varies, necessitating additional investigation. Here, we present genetic evidence further supporting the interaction between sap and the RBPs of AP50c and Wip1 using fluorescently tagged proteins and a panel of B. anthracis mutants. These results showed that the deletion of the sap gene, as well as the deletion of csaB, whose encoded protein anchors sap to the bacterial S-layer, resulted in the loss of RBP binding. Binding could then be rescued by expressing these genes in trans. We also found that the RBP of the γ-like prophage λBa03 relied on csaB activity for binding, possibly by a different mechanism. RBPλBa03 binding to B. anthracis cells was also unique in that it was not ablated by heat inactivation of vegetative cells, suggesting that its receptor is still functional following incubation at 98°C. These results extend our understanding of the diverse attachment and entry strategies used by B. anthracis phages, enabling future assay development.
Collapse
Affiliation(s)
- Samantha Forrest
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, United States
| | - Sarah Ton
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, United States
| | - Samantha L. Sholes
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, United States
| | - Sarah Harrison
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, United States
| | - Roger D. Plaut
- Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, United States
| | - Kathleen Verratti
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, United States
| | | | | | - Bryan Necciai
- Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense (JPEO-CBRND), Joint Project Lead for CBRND Enabling Biotechnologies, Frederick, MD, United States
| | - Shanmuga Sozhamannan
- Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense (JPEO-CBRND), Joint Project Lead for CBRND Enabling Biotechnologies, Frederick, MD, United States
- Joint Research and Development, Inc., Stafford, VA, United States
| | - Sarah L. Grady
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, United States
| |
Collapse
|
4
|
Petrišič N, Adamek M, Kežar A, Hočevar SB, Žagar E, Anderluh G, Podobnik M. Structural basis for the unique molecular properties of broad-range phospholipase C from Listeria monocytogenes. Nat Commun 2023; 14:6474. [PMID: 37838694 PMCID: PMC10576769 DOI: 10.1038/s41467-023-42134-4] [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: 03/13/2023] [Accepted: 09/28/2023] [Indexed: 10/16/2023] Open
Abstract
Listeriosis is one of the most serious foodborne diseases caused by the intracellular bacterium Listeria monocytogenes. Its two major virulence factors, broad-range phospholipase C (LmPC-PLC) and the pore-forming toxin listeriolysin O (LLO), enable the bacterium to spread in the host by destroying cell membranes. Here, we determine the crystal structure of LmPC-PLC and complement it with the functional analysis of this enzyme. This reveals that LmPC-PLC has evolved several structural features to regulate its activity, including the invariant position of the N-terminal tryptophan (W1), the structurally plastic active site, Zn2+-dependent activity, and the tendency to form oligomers with impaired enzymatic activity. We demonstrate that the enzymatic activity of LmPC-PLC can be specifically inhibited by its propeptide added in trans. Furthermore, we show that the phospholipase activity of LmPC-PLC facilitates the pore-forming activity of LLO and affects the morphology of LLO oligomerization on lipid membranes, revealing the multifaceted synergy of the two virulence factors.
Collapse
Affiliation(s)
- Nejc Petrišič
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
- PhD Program 'Biosciences', Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Maksimiljan Adamek
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Andreja Kežar
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Samo B Hočevar
- Department of Analytical Chemistry, National Institute of Chemistry, Ljubljana, Slovenia
| | - Ema Žagar
- Department of Polymer Chemistry and Technology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Marjetka Podobnik
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia.
| |
Collapse
|
5
|
Yehuda A, Malach E, Vanunu Ofri S, Slamti L, Kuo SH, Lau JZ, Oh MW, Adeoye J, Shlezinger N, Lereclus D, Lau GW, Hayouka Z. The quorum-sensing peptidic inhibitor rescues host immune system eradication: A novel infectivity mechanism. Proc Natl Acad Sci U S A 2023; 120:e2301045120. [PMID: 37607229 PMCID: PMC10469338 DOI: 10.1073/pnas.2301045120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 06/23/2023] [Indexed: 08/24/2023] Open
Abstract
Subverting the host immune system is a major task for any given pathogen to assure its survival and proliferation. For the opportunistic human pathogen Bacillus cereus (Bc), immune evasion enables the establishment of potent infections. In various species of the Bc group, the pleiotropic regulator PlcR and its cognate cell-cell signaling peptide PapR7 regulate virulence gene expression in response to fluctuations in population density, i.e., a quorum-sensing (QS) system. However, how QS exerts its effects during infections and whether PlcR confers the immune evading ability remain unclear. Herein, we report how interception of the QS communication in Bc obliterates the ability to affect the host immune system. Here, we designed a peptide-based QS inhibitor that suppresses PlcR-dependent virulence factor expression and attenuates Bc infectivity in mouse models. We demonstrate that the QS peptidic inhibitor blocks host immune system-mediated eradication by reducing the expression of PlcR-regulated major toxins similarly to the profile that was observed for isogenic strains. Our findings provide evidence that Bc infectivity is regulated by QS circuit-mediated destruction of host immunity, thus reveal a interesting strategy to limit Bc virulence and enhance host defense. This peptidic quorum-quenching agent constitutes a readily accessible chemical tool for studying how other pathogen QS systems modulate host immunity and forms a basis for development of anti-infective therapeutics.
Collapse
Affiliation(s)
- Avishag Yehuda
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
| | - Einav Malach
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
| | - Shahar Vanunu Ofri
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
| | - Leyla Slamti
- Unité Micalis, Domaine de La Minière, Unité Mixte de Recherche 1319, Institut National de la Recherche Agronomique, 78280Guyancourt, France
| | - Shanny Hsuan Kuo
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL61802
| | - Jonathan Z. Lau
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL61802
| | - Myung Whan Oh
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL61802
| | - John Adeoye
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
| | - Neta Shlezinger
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
| | - Didier Lereclus
- Unité Micalis, Domaine de La Minière, Unité Mixte de Recherche 1319, Institut National de la Recherche Agronomique, 78280Guyancourt, France
| | - Gee W. Lau
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL61802
| | - Zvi Hayouka
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agricultural, Food & Environment, The Hebrew University of Jerusalem, Rehovot76100, Israel
| |
Collapse
|
6
|
Manoharan S, Taylor-Joyce G, Brooker TA, Hernández Rodríguez CS, Hapeshi A, Baldwin V, Baillie L, Oyston PCF, Waterfield NR. From cereus to anthrax and back again: Assessment of the temperature-dependent phenotypic switching in the "cross-over" strain Bacillus cereus G9241. Front Microbiol 2023; 14:1113562. [PMID: 36937299 PMCID: PMC10017872 DOI: 10.3389/fmicb.2023.1113562] [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: 12/01/2022] [Accepted: 02/07/2023] [Indexed: 03/06/2023] Open
Abstract
Bacillus cereus G9241 was isolated from a Louisiana welder suffering from an anthrax-like infection. The organism carries two transcriptional regulators that have previously been proposed to be incompatible with each other in Bacillus anthracis: the pleiotropic transcriptional regulator PlcR found in most members of the Bacillus cereus group but truncated in all B. anthracis isolates, and the anthrax toxin regulator AtxA found in all B. anthracis strains and a few B. cereus sensu stricto strains. Here we report cytotoxic and hemolytic activity of cell free B. cereus G9241 culture supernatants cultured at 25°C to various eukaryotic cells. However, this is not observed at the mammalian infection relevant temperature 37°C, behaving much like the supernatants generated by B. anthracis. Using a combination of genetic and proteomic approaches to understand this unique phenotype, we identified several PlcR-regulated toxins to be secreted highly at 25°C compared to 37°C. Furthermore, results suggest that differential expression of the protease involved in processing the PlcR quorum sensing activator molecule PapR appears to be the limiting step for the production of PlcR-regulated toxins at 37°C, giving rise to the temperature-dependent hemolytic and cytotoxic activity of the culture supernatants. This study provides an insight on how B. cereus G9241 is able to "switch" between B. cereus and B. anthracis-like phenotypes in a temperature-dependent manner, potentially accommodating the activities of both PlcR and AtxA.
Collapse
Affiliation(s)
- Shathviga Manoharan
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Grace Taylor-Joyce
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Thomas A. Brooker
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | | | - Alexia Hapeshi
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | | | - Les Baillie
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | | | - Nicholas R. Waterfield
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| |
Collapse
|
7
|
Wang Y, Zhang J, Yuan Z, Sun L. Characterization of the pathogenicity of a Bacillus cereus isolate from the Mariana Trench. Virulence 2022; 13:1062-1075. [PMID: 35733351 PMCID: PMC9235904 DOI: 10.1080/21505594.2022.2088641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Bacillus cereus is an important opportunistic pathogen widely distributed in the environment. In this study, we reported the isolation and characterization of a B. cereus isolate, MB1, from the Challenger Deep of the Mariana Trench. MB1 is aerobic, motile, and able to form endospores. It possesses 5966 genes distributed on a circular chromosome and two plasmids. The MB1 genome contains 14 sets of 23S, 5S, and 16S ribosomal RNA operons, 106 tRNA genes, 4 sRNA genes, 12 genomic islands, 13 prophages, and 302 putative virulence genes, including enterotoxins and cytolysins. Infection studies showed that MB1 was able to cause acute and lethal infection in fish and mice, and was highly toxic to mammalian cells. MB1 induced, in a dose-dependent manner, pyroptotic cell death, characterized by activation of caspase-1, cleavage of gasdermin D, and release of IL-1β and IL-18. MB1 spores exhibited swimming and haemolytic capacity, but were severely attenuated in pathogenicity, which, however, was regained to the full extent when the spores germinated under suitable conditions. Taken together, these results provide new insights into the biological and pathogenic mechanism of deep sea B. cereus.
Collapse
Affiliation(s)
- Yujian Wang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jian Zhang
- School of Ocean, Yan tai University, Yantai, China
| | - Zihao Yuan
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Li Sun
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
8
|
Structural and Functional Analysis of Toxin and Small RNA Gene Promoter Regions in Bacillus anthracis. J Bacteriol 2022; 204:e0020022. [PMID: 36043862 PMCID: PMC9487513 DOI: 10.1128/jb.00200-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It was previously demonstrated that anthrax toxin activator (AtxA) binds directly to the σA-like promoter region of pagA (encoding protective antigen, PA) immediately upstream of the RNA polymerase binding site. In this study, using electrophoretic mobility shift assays and in vivo analyses, we identified AtxA-binding sites in the promoter regions of the lef and cya genes (encoding lethal and edema factors, respectively) and of two Bacillus anthracis small RNAs (XrrA and XrrB). Activities of all four newly studied promoters were enhanced in the presence of CO2/bicarbonate and AtxA, as previously seen for the pagA promoter. Notably, the cya promoter was less activated by AtxA and CO2/bicarbonate conditions. The putative promoter of a recently described third small RNA, XrrC, showed a negligible response to AtxA and CO2/bicarbonate. RNA polymerase binding sites of the newly studied promoters show no consensus and differ from the σA-like promoter region of pagA. In silico analysis of the probable AtxA binding sites in the studied promoters revealed several palindromes. All the analyzed palindromes showed very little overlap with the σA-like pagA promoter. It remains unclear as to how AtxA and DNA-dependent RNA-polymerase identify such diverse DNA-sequences and differentially regulate promoter activation of the studied genes. IMPORTANCE Anthrax toxin activator (AtxA) is the major virulence regulator of Bacillus anthracis, the causative agent of anthrax. Understanding AtxA's mechanism of regulation could facilitate the development of therapeutics for B. anthracis infection. We provide evidence that AtxA binds to the promoters of the cya, lef, xrrA, and xrrB genes. In vivo assays confirmed the activities of all four promoters were enhanced in the presence of AtxA and CO2/bicarbonate, as previously seen for the pagA promoter. The cya and lef genes encode important toxin components. The xrrA and xrrB genes encode sRNAs with a suggested function as cell physiology regulators. Our data provides further evidence for the direct regulatory role of AtxA that was previously shown with the pagA promoter.
Collapse
|
9
|
Algammal AM, Alfifi KJ, Mabrok M, Alatawy M, Abdel-moneam DA, Alghamdi S, Azab MM, Ibrahim RA, Hetta HF, El-Tarabili RM. Newly Emerging MDR B. cereus in Mugil seheli as the First Report Commonly Harbor nhe, hbl, cytK, and pc-plc Virulence Genes and bla1, bla2, tetA, and ermA Resistance Genes. Infect Drug Resist 2022; 15:2167-2185. [PMID: 35498633 PMCID: PMC9052338 DOI: 10.2147/idr.s365254] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/15/2022] [Indexed: 01/23/2023] Open
Abstract
Background Bacillus cereus is a common food poisoning pathogen in humans. This study aimed to investigate the prevalence, molecular typing, antibiogram profile, pathogenicity, dissemination of virulence and antibiotic resistance genes associated with natural B. cereus infection among Mugil seheli. Methods Consequently, 120 M. seheli (40 healthy and 80 diseased) were obtained from private fish farms in Port-said Governorate, Egypt. Afterward, samples were processed for clinical, post-mortem, and bacteriological examinations. The recovered isolates were tested for antimicrobial susceptibility, phenotypic assessment of virulence factors, pathogeneicity, and PCR-based detection of virulence and antibiotic resistance genes. Results B. cereus was isolated from 30 (25%) examined fish; the highest prevalence was noticed in the liver (50%). The phylogenetic and sequence analyses of the gyrB gene revealed that the tested B. cereus isolate displayed a high genetic similarity with other B. cereus strains from different origins. All the recovered B. cereus isolates (n =60, 100%) exhibited β-hemolytic and lecithinase activities, while 90% (54/60) of the tested isolates were biofilm producers. Using PCR, the tested B. cereus isolates harbor nhe, hbl, cytK, pc-plc, and ces virulence genes with prevalence rates of 91.6%, 86.6%, 83.4%, 50%, and 33.4%, respectively. Moreover, 40% (24/60) of the tested B. cereus isolates were multidrug-resistant (MDR) to six antimicrobial classes and carried the bla1, bla2, tetA, and ermA genes. The experimentally infected fish with B. cereus showed variable mortality in direct proportion to the inoculated doses. Conclusion As far as we know, this is the first report that emphasized the existence of MDR B. cereus in M. seheli that reflects a threat to the public health and the aquaculture sector. Newly emerging MDR B. cereus in M. seheli commonly carried virulence genes nhe, hbl, cytK, and pc-plc, as well as resistance genes bla1, bla2, tetA, and ermA.
Collapse
Affiliation(s)
- Abdelazeem M Algammal
- Department of Bacteriology, Immunology, and Mycology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, 41522, Egypt
| | - Khyreyah J Alfifi
- Biology Department, Faculty of Science, Tabuk University, Tabuk, 71421, Saudi Arabia
| | - Mahmoud Mabrok
- Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, 41522, Egypt
| | - Marfat Alatawy
- Biology Department, Faculty of Science, Tabuk University, Tabuk, 71421, Saudi Arabia
| | - Dalia A Abdel-moneam
- Department of Aquatic Animal Medicine and Management, Faculty of Veterinary Medicine, Cairo University, Cairo, 12613, Egypt
| | - Saad Alghamdi
- Laboratory Medicine Department, Faculty of Applied Medical Sciences, Umm Al-Qura University, Makkah, 21955, Saudi Arabia
| | - Marwa M Azab
- Department of Microbiology and Immunology, Faculty of Pharmacy, Suez Canal University, Ismailia, 41522, Egypt
| | - Reham A Ibrahim
- Marine Environmental Division- National Institute of Oceanography and Fisheries (NIOF), Suez, 43511, Egypt
| | - Helal F Hetta
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, 71515, Egypt
| | - Reham M El-Tarabili
- Department of Bacteriology, Immunology, and Mycology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, 41522, Egypt
| |
Collapse
|
10
|
Bhat AH, Dar KB, Khan A, Alshahrani S, Alshehri SM, Ghoneim MM, Alam P, Shakeel F. Tricyclodecan-9-yl-Xanthogenate (D609): Mechanism of Action and Pharmacological Applications. Int J Mol Sci 2022; 23:3305. [PMID: 35328726 PMCID: PMC8954530 DOI: 10.3390/ijms23063305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 12/04/2022] Open
Abstract
Tricyclodecan-9-yl xanthogenate (D609) is a synthetic tricyclic compound possessing a xanthate group. This xanthogenate compound is known for its diverse pharmacological properties. Over the last three decades, many studies have reported the biological activities of D609, including antioxidant, antiapoptotic, anticholinergic, anti-tumor, anti-inflammatory, anti-viral, anti-proliferative, and neuroprotective activities. Its mechanism of action is extensively attributed to its ability to cause the competitive inhibition of phosphatidylcholine (PC)-specific phospholipase C (PC-PLC) and sphingomyelin synthase (SMS). The inhibition of PCPLC or SMS affects secondary messengers with a lipidic nature, i.e., 1,2-diacylglycerol (DAG) and ceramide. Various in vitro/in vivo studies suggest that PCPLC and SMS inhibition regulate the cell cycle, block cellular proliferation, and induce differentiation. D609 acts as a pro-inflammatory cytokine antagonist and diminishes Aβ-stimulated toxicity. PCPLC enzymatic activity essentially requires Zn2+, and D609 might act as a potential chelator of Zn2+, thereby blocking PCPLC enzymatic activity. D609 also demonstrates promising results in reducing atherosclerotic plaque formation, post-stroke cerebral infarction, and cancer progression. The present compilation provides a comprehensive mechanistic insight into D609, including its chemistry, mechanism of action, and regulation of various pharmacological activities.
Collapse
Affiliation(s)
- Aashiq Hussain Bhat
- Department of Clinical Biochemistry, University of Kashmir, Srinagar 190006, India; (A.H.B.); (K.B.D.)
| | - Khalid Bashir Dar
- Department of Clinical Biochemistry, University of Kashmir, Srinagar 190006, India; (A.H.B.); (K.B.D.)
| | - Andleeb Khan
- Department of Pharmacology and Toxicology, College of Pharmacy, Jazan University, Jazan 45142, Saudi Arabia;
| | - Saeed Alshahrani
- Department of Pharmacology and Toxicology, College of Pharmacy, Jazan University, Jazan 45142, Saudi Arabia;
| | - Sultan M. Alshehri
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; (S.M.A.); (F.S.)
| | - Mohammed M. Ghoneim
- Department of Pharmacy Practice, College of Pharmacy, AlMaarefa University, Ad Diriyah 13713, Saudi Arabia;
| | - Prawez Alam
- Department of Pharmacognosy, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia;
| | - Faiyaz Shakeel
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; (S.M.A.); (F.S.)
| |
Collapse
|
11
|
Haddaji N, Chakroun I, Fdhila K, Smati H, Bakhrouf A, Mzoughi R. Pathogenic Impacts of Bacillus cereus Strains on Crassostrea gigas. Foodborne Pathog Dis 2022; 19:151-158. [PMID: 35029524 DOI: 10.1089/fpd.2021.0050] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Regarding the economic importance of bivalve farming, a great deal of interest has recently been devoted to studying the pathogenesis of infectious diseases of these mollusks to prepare for public health emergencies. Bacillus cereus is one of these pathogens; it is a ubiquitous soil bacterium responsible for many types of gastrointestinal diseases associated with food. This study was conducted to determine the pathogenic effect of B. cereus on Crassostrea gigas. This effect was studied by assessing hemocytes death using flow cytometry analysis. The results showed that only ∼15% of C. gigas were able to survive after B. cereus artificial infection with 108 CFU (colony-forming unit)/oyster. Evenly, the percentage of nonviable hemocytes gradually increased with the concentration of B. cereus, with a peak value of ∼40% after infection. Indeed, findings showed that this strain is harmful to C. gigas.
Collapse
Affiliation(s)
- Najla Haddaji
- Department of Biology, Faculty of Sciences, University of Ha'il, Ha'il, Kingdom of Saudi Arabia.,Laboratory of Analysis, Treatment and Valorization of Pollutants of the Environment and Products, Faculty of Pharmacy, Monastir, Tunisia
| | - Ibtissem Chakroun
- Laboratory of Analysis, Treatment and Valorization of Pollutants of the Environment and Products, Faculty of Pharmacy, Monastir, Tunisia
| | - Kais Fdhila
- Laboratory of Analysis, Treatment and Valorization of Pollutants of the Environment and Products, Faculty of Pharmacy, Monastir, Tunisia
| | - Hela Smati
- Laboratory of Analysis, Treatment and Valorization of Pollutants of the Environment and Products, Faculty of Pharmacy, Monastir, Tunisia
| | - Amina Bakhrouf
- Laboratory of Analysis, Treatment and Valorization of Pollutants of the Environment and Products, Faculty of Pharmacy, Monastir, Tunisia
| | - Ridha Mzoughi
- Laboratory of Analysis, Treatment and Valorization of Pollutants of the Environment and Products, Faculty of Pharmacy, Monastir, Tunisia
| |
Collapse
|
12
|
Yokotani A, Takahashi F, Aoyama R, Kamoshida G, Kosaka T, Nakanishi M, Fujita N. Differences in the sequence of PlcR transcriptional regulator binding site affect sphingomyelinase production in Bacillus cereus. Microbiol Immunol 2021; 66:157-165. [PMID: 34914844 DOI: 10.1111/1348-0421.12959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/08/2021] [Accepted: 12/12/2021] [Indexed: 11/28/2022]
Abstract
Bacillus cereus is an opportunistic pathogen that often causes severe infections such as bacteremia, with sphingomyelinase (SMase) being a crucial virulence factor. Although many strains of B. cereus carry the SMase gene, they are classified as SMase-producing and non-producing strains. The reason for different SMase production among B. cereus strains remains unknown. In this study, we investigated the relationship between SMase and the PlcR transcriptional regulation system to clarify the mechanism leading to varied SMase production among B. cereus strains. We analyzed the sequence of the PlcR box, which is a transcriptional regulator binding site, located at the promoter region of SMase and phosphatidylcholine-specific phospholipase C. Based on differences in the PlcR box sequences, we classified the B. cereus strains into three groups (I, II, and III). SMase expression and activity were hardly detected in Group III strains. In Group I strains, SMase activity and its expression were maximal at the onset of the stationary phase and decreased during the stationary phase, whereas those were maintained during the stationary phase in Group II stains. On injection of B. cereus strains into mice or incubation with macrophages for phagocytosis assay, the SMase-producing Group I and II strains showed higher pathogenicity than Group III strains. These findings suggest that PlcR box sequence in B. cereus affects the production of SMase, which may provide important clinical information for the detection of highly pathogenic B. cereus strains. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Atsushi Yokotani
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Fumi Takahashi
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Ryoko Aoyama
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Go Kamoshida
- Department of Microbiology and Infection Control Science, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Tadashi Kosaka
- Department of Pharmacy, University Hospital, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Masaki Nakanishi
- Division of Infection Control & Laboratory Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Naohisa Fujita
- Kyoto Prefectural Institute of Public Health and Environment, Kyoto, Japan
| |
Collapse
|
13
|
Eddehech A, Smichi N, Violot S, Bettler E, Brizuela L, Noiriel A, Abousalham A, Zarai Z. Deciphering the recombinant thermostable phosphatidylcholine-specific phospholipase C activity from Bacillus thuringiensis: Biochemical and interfacial properties. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
14
|
Lee HY, Loong SK, Ya'cob Z, Low VL, Teoh BT, Ahmad-Nasrah SN, Yap PC, Sofian-Azirun M, Takaoka H, AbuBakar S, Adler PH. Culturable bacteria in adults of a Southeast Asian black fly, Simulium tani (Diptera:Simuliidae). Acta Trop 2021; 219:105923. [PMID: 33878305 DOI: 10.1016/j.actatropica.2021.105923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/09/2021] [Accepted: 04/10/2021] [Indexed: 10/21/2022]
Abstract
Although the microbiome of blood-feeding insects serves an integral role in host physiology, both beneficial and pathogenic, little is known of the microbial community of black flies. An investigation, therefore, was undertaken to identify culturable bacteria from one of Malaysia's most common black flies, Simulium tani Takaoka and Davies, using 16S rDNA sequencing, and then evaluate the isolates for antibiotic resistance and virulence genes. A total of 20 isolates representing 11 bacterial species in four genera were found. Five isolates showed β-hemolysis on Columbia agar, and virulence genes were found in three of these isolates. Some degree of resistance to six of the 12 tested antibiotics was found among the isolates. The baseline data from this study suggest rich opportunities for comparative studies exploring the diversity and roles of the microbiome of S. tani and other Southeast Asian black flies.
Collapse
|
15
|
Amin HM, Tawfick MM. High Risk of Potential Diarrheagenic Bacillus cereus in Diverse Food Products in Egypt. J Food Prot 2021; 84:1033-1039. [PMID: 33465240 DOI: 10.4315/jfp-20-384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 01/11/2021] [Indexed: 11/11/2022]
Abstract
ABSTRACT Bacillus cereus is one of the important foodborne pathogens that can be found in various foodstuffs, causes diarrheal and/or emetic syndromes, and can cause severe systemic diseases that may lead to death. This study was conducted to evaluate the prevalence, antimicrobial susceptibility profile, pathogenic potential, and genotypic diversity of B. cereus isolates recovered from diverse food products collected from markets in Cairo, Egypt. Of 165 food samples investigated in this study, 39 (24%) were positive for B. cereus, with contamination levels of 2 to 6 log CFU/g or mL and a higher prevalence of levels >3 log CFU. Antimicrobial susceptibility testing revealed that the B. cereus isolates were fully sensitive to all tested antimicrobial agents except β-lactams. The pathogenic potential of the 39 B. cereus isolates was assessed by detecting and profiling genes encoding virulence factors or toxins: the chromosomal genes hblA, bceT, plc, sph, nheA, entFM, and cytK associated with the diarrheal syndrome and the plasmid ces gene associated with the emetic syndrome. The most frequently detected genes were hblA, nheA, and entFM. All isolates harbored more than one of the diarrheal enterotoxin genes, and the genetic profile hblA-bceT-nheA-entFM-cytK-plc-sph was the most prevalent (20 of 39 isolates). The emetic toxin gene ces was not detected in any isolate. Enterobacterial repetitive intergenic consensus analysis of the 20 B. cereus isolates harboring the most prevalent genetic profile revealed that these isolates were genetically distinct, with a Simpson index of diversity value of 0.989. These findings provide useful information for public health management and serve as a warning of the potential risk of diarrheagenic B. cereus in diverse food products. Therefore, extensive study of the epidemiology of this food pathogen in Egypt is warranted. Strict procedures should be developed to monitor, protect, and safely handle food products, particularly ready-to-eat foodstuffs that are usually consumed without heat treatment. HIGHLIGHTS
Collapse
Affiliation(s)
- Heba M Amin
- Department of Microbiology and Immunology, Faculty of Pharmacy, October University for Modern Sciences and Arts (MSA), 6th of October City, Giza, Egypt
| | - Mahmoud M Tawfick
- Department of Microbiology and Immunology, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City, Cairo, Egypt; and
- Department of Microbiology and Public Health, Faculty of Pharmacy, Heliopolis University, Cairo, Egypt
| |
Collapse
|
16
|
Kim HS, Arellano K, Park H, Todorov SD, Kim B, Kang H, Park YJ, Suh DH, Jung ES, Ji Y, Holzapfel WH. Assessment of the safety and anti-inflammatory effects of three Bacillus strains in the respiratory tract. Environ Microbiol 2021; 23:3077-3098. [PMID: 33899316 DOI: 10.1111/1462-2920.15530] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/12/2021] [Indexed: 11/29/2022]
Abstract
Chronic respiratory diseases are part of accumulating health problems partly due to worldwide increase in air pollution. By their antimicrobial and immunomodulatory properties, some probiotics constitute promising alternatives for the prevention and treatment of chronic respiratory diseases. We have isolated Bacillus strains from Korean fermented foods and selected three potentially probiotic strains (two Bacillus subtilis and one Bacillus amyloliquefaciens) based on safety, antimicrobial efficacy, activity against airborne pathogens and their immunomodulatory properties in vivo. Safety evaluation included in silico analysis for confirming absence of virulence genes. Safety for the respiratory tract was confirmed by an in vivo pathogenicity test using a murine model. Antimicrobial activity was displayed against several airborne pathogens. Potential antimicrobial metabolites such as 2,3-butanediol and propylene glycol were identified as possible antagonistic agents. Immunomodulatory properties in vitro were confirmed by upregulation of IL-10 expression in a macrophage cell line. Intranasal instillation and inhalation in an ovalbumin (OVA)-induced lung inflammation murine model reduced T helper type 2 (Th2) cytokines at transcriptional and protein levels in the lungs. The safety and potentially beneficial role of these Bacillus strains could be demonstrated for the respiratory tract of a murine model.
Collapse
Affiliation(s)
- Hye-Shin Kim
- Department of Advanced Convergence, Handong Global University, Pohang, Gyungbuk, 37554, Republic of Korea
| | - Karina Arellano
- Department of Advanced Convergence, Handong Global University, Pohang, Gyungbuk, 37554, Republic of Korea
| | - Haryung Park
- HEM Inc., Pohang, Gyungbuk, 37554, Republic of Korea
| | - Svetoslav D Todorov
- Department of Advanced Convergence, Handong Global University, Pohang, Gyungbuk, 37554, Republic of Korea
| | - Bobae Kim
- HEM Inc., Pohang, Gyungbuk, 37554, Republic of Korea
| | - Hyeji Kang
- Department of Advanced Convergence, Handong Global University, Pohang, Gyungbuk, 37554, Republic of Korea.,HEM Inc., Pohang, Gyungbuk, 37554, Republic of Korea
| | - Yu Jin Park
- HEM Inc., 77, Changnyong-daero 256 Beon-gil, Suwon-si, Gyeonggi-do, 16229, Republic of Korea
| | - Dong Ho Suh
- HEM Inc., 77, Changnyong-daero 256 Beon-gil, Suwon-si, Gyeonggi-do, 16229, Republic of Korea
| | - Eun Sung Jung
- HEM Inc., 77, Changnyong-daero 256 Beon-gil, Suwon-si, Gyeonggi-do, 16229, Republic of Korea
| | - Yosep Ji
- Department of Advanced Convergence, Handong Global University, Pohang, Gyungbuk, 37554, Republic of Korea.,HEM Inc., 77, Changnyong-daero 256 Beon-gil, Suwon-si, Gyeonggi-do, 16229, Republic of Korea
| | - Wilhelm H Holzapfel
- Department of Advanced Convergence, Handong Global University, Pohang, Gyungbuk, 37554, Republic of Korea.,HEM Inc., Pohang, Gyungbuk, 37554, Republic of Korea
| |
Collapse
|
17
|
Bacillus cereus: Epidemiology, Virulence Factors, and Host-Pathogen Interactions. Trends Microbiol 2020; 29:458-471. [PMID: 33004259 DOI: 10.1016/j.tim.2020.09.003] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 12/30/2022]
Abstract
The toxin-producing bacterium Bacillus cereus is an important and neglected human pathogen and a common cause of food poisoning. Several toxins have been implicated in disease, including the pore-forming toxins hemolysin BL (HBL) and nonhemolytic enterotoxin (NHE). Recent work revealed that HBL binds to the mammalian surface receptors LITAF and CDIP1 and that both HBL and NHE induce potassium efflux and activate the NLRP3 inflammasome, leading to pyroptosis. These mammalian receptors, in part, contribute to inflammation and pathology. Other putative virulence factors of B. cereus include cytotoxin K, cereulide, metalloproteases, sphingomyelinase, and phospholipases. In this review, we highlight the latest progress in our understanding of B. cereus biology, epidemiology, and pathogenesis, and discuss potential new directions for research in this field.
Collapse
|
18
|
Oda M, Yokotani A, Hayashi N, Kamoshida G. Role of Sphingomyelinase in the Pathogenesis of Bacillus cereus Infection. Biol Pharm Bull 2020; 43:250-253. [DOI: 10.1248/bpb.b19-00762] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Masataka Oda
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University
| | - Atsushi Yokotani
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University
| | - Naoki Hayashi
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University
| | - Go Kamoshida
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University
| |
Collapse
|
19
|
Abdeen EES, Hussien H, Hadad GAE, Mousa WS. Prevalence of Virulence Determinants among Bacillus cereus Isolated from Milk Products with Potential Public Health Concern. Pak J Biol Sci 2020; 23:206-212. [PMID: 31944080 DOI: 10.3923/pjbs.2020.206.212] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND OBJECTIVE Bacillus cereus is described as one of the public health pathogen causing severe food poisoning outbreaks worldwide. Accurate surveillance about B. cereus in Egypt is scanty. For this reason, the current study was conducted to determine the prevalence of B. cereus and its virulence genes among milk powder and Ras-cheese products. MATERIALS AND METHODS Two hundred samples (130 and 70) from milk powder and Ras-cheese, respectively were aseptically collected and cultured onto specific media. The obtained isolates were subjected to mPCR for screening of virulence genes (nhe, cytK, pc-plc, hblD, hbI and ces) among of B. cereus isolates that obtained from milk powder and Ras-cheese. RESULTS The result revealed that B. cereus was recovered with 6.9 and 8.5% from milk powder and Ras-cheese, respectively. The nhe gene was detected and dominated in all isolates 100% from both products. In milk powder, pc-plc was the most prevalent gene (100%). However, cytK, hblD, hbl and ces genes were prevalent with 55.5, 33.3, 33.3 and 22.2%, respectively. Regarding to Ras-cheese, the prevalence of cytK was (83.33%) while each of hbI, hblD, pc-plc and ces genes were recovered in 50% of tested isolates. CONCLUSION This result provided an important epidemiological view about the contamination rate and the most prevalent virulence genes of B. cereus in milk products in Egypt.
Collapse
|
20
|
McCall RM, Sievers ME, Fattah R, Ghirlando R, Pomerantsev AP, Leppla SH. Bacillus anthracis Virulence Regulator AtxA Binds Specifically to the pagA Promoter Region. J Bacteriol 2019; 201:e00569-19. [PMID: 31570528 PMCID: PMC6832065 DOI: 10.1128/jb.00569-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 01/12/2023] Open
Abstract
Anthrax toxin activator (AtxA) is the master virulence gene regulator of Bacillus anthracis It regulates genes on the chromosome as well as the pXO1 and pXO2 plasmids. It is not clear how AtxA regulates these genes, and direct binding of AtxA to its targets has not been shown. It has been previously suggested that AtxA and other proteins in the Mga/AtxA global transcriptional regulators family bind to the curvature of their DNA targets, although this has never been experimentally proven. Using electrophoretic mobility shift assays, we demonstrate that AtxA binds directly to the promoter region of pagA upstream of the RNA polymerase binding site. We also demonstrate that in vitro, CO2 appears to have no role in AtxA binding. However, phosphomimetic and phosphoablative substitutions in the phosphotransferase system (PTS) regulation domains (PRDs) do appear to influence AtxA binding and pagA regulation. In silico, in vitro, and in vivo analyses demonstrate that one of two hypothesized stem-loops located upstream of the RNA polymerase binding site in the pagA promoter region is important for AtxA binding in vitro and pagA regulation in vivo Our study clarifies the mechanism by which AtxA interacts with one of its targets.IMPORTANCE Anthrax toxin activator (AtxA) regulates the major virulence genes in Bacillus anthracis The bacterium produces the anthrax toxins, and understanding the mechanism of toxin production may facilitate the development of therapeutics for B. anthracis infection. Since the discovery of AtxA 25 years ago, the mechanism by which it regulates its targets has largely remained a mystery. Here, we provide evidence that AtxA binds to the promoter region of the pagA gene encoding the main central protective antigen (PA) component of the anthrax toxin. These data suggest that AtxA binding plays a direct role in gene regulation. Our work also assists in clarifying the role of CO2 in AtxA's gene regulation and provides more evidence for the role of AtxA phosphorylation in virulence gene regulation.
Collapse
Affiliation(s)
- Rita M McCall
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Mary E Sievers
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Rasem Fattah
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Andrei P Pomerantsev
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Stephen H Leppla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| |
Collapse
|
21
|
Jessberger N, Kranzler M, Da Riol C, Schwenk V, Buchacher T, Dietrich R, Ehling-Schulz M, Märtlbauer E. Assessing the toxic potential of enteropathogenic Bacillus cereus. Food Microbiol 2019; 84:103276. [PMID: 31421762 DOI: 10.1016/j.fm.2019.103276] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/18/2019] [Accepted: 07/20/2019] [Indexed: 12/17/2022]
Abstract
The diarrheal type of food poisoning caused by enteropathogenic Bacillus cereus has been linked to various exotoxins. Best described are the non-hemolytic enterotoxin (Nhe), hemolysin BL (Hbl), and cytotoxin K (CytK). Due to the ubiquitous prevalence of B. cereus in soil and crops and its ability to form highly resistant endospores, contaminations during food production and processing cannot be completely avoided. Although phylogenetically closely related, enteropathogenic B. cereus strains show a high versatility of their toxic potential. Thus, functional tools for evaluating the pathogenic potential are urgently needed in order to predict hazardous food contaminations. As the diarrheal syndrome is the result of a toxico-infection with enterotoxin production in the intestine, the entire passage of the bacteria within the host, from spore survival in the stomach, spore germination, host cell adherence, and motility, to enterotoxin production under simulated intestinal conditions was compared in a panel of 20 strains, including high pathogenic as well as apathogenic ones. This approach resulted in an overarching virulence analysis scheme. In parallel, we searched for potential toxico-specific secreted markers to discriminate low and high pathogenic strains. To this end, we targeted known exotoxins using an easy to implement immunoblotting approach as well as a caseinolytic exoprotease activity assay. Overall, Nhe component B, sphingomyelinase, and exoproteases showed good correlation with the complex virulence analysis scheme and can serve as a template for future fast and easy risk assessment tools to be implemented in routine diagnostic procedures and HACCP studies.
Collapse
Affiliation(s)
- Nadja Jessberger
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764, Oberschleißheim, Germany.
| | - Markus Kranzler
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210, Vienna, Austria
| | - Claudia Da Riol
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764, Oberschleißheim, Germany
| | - Valerie Schwenk
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764, Oberschleißheim, Germany
| | - Tanja Buchacher
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210, Vienna, Austria
| | - Richard Dietrich
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764, Oberschleißheim, Germany
| | - Monika Ehling-Schulz
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210, Vienna, Austria
| | - Erwin Märtlbauer
- Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764, Oberschleißheim, Germany
| |
Collapse
|
22
|
Arcanobacterium haemolyticum Utilizes Both Phospholipase D and Arcanolysin To Mediate Its Uptake into Nonphagocytic Cells. Infect Immun 2019; 87:IAI.00832-18. [PMID: 30745329 DOI: 10.1128/iai.00832-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 02/04/2019] [Indexed: 01/14/2023] Open
Abstract
Arcanobacterium haemolyticum is an emerging human pathogen that causes pharyngitis and wound infections. A few studies have suggested that A. haemolyticum is able to induce its uptake into nonphagocytic epithelial cells, but the bacterial factors associated with host cell invasion and the host cell processes involved have yet to be studied. We investigated how two A. haemolyticum virulence factors, arcanolysin (ALN) and phospholipase D (PLD), affect the ability of the bacteria to adhere to and subsequently invade Detroit 562 pharyngeal epithelial cells. The sphingomyelinase activity of phospholipase D was necessary to increase bacterial adherence, while the absence of a functional arcanolysin had no effect on A. haemolyticum adherence but did lead to a decrease in A. haemolyticum invasion into Detroit 562 cells. Because of the known roles of cholesterol-dependent cytolysins in disrupting calcium gradients and inducing F-actin-mediated bacterial internalization, we sought to determine whether ALN and PLD played a similar role in the ability of A. haemolyticum to invade nonphagocytic cells. Elimination of extracellular calcium and inhibition of the Arp2/3 complex or F-actin polymerization also caused a decrease in the ability of A. haemolyticum to invade Detroit 562 cells. Overall, our findings suggest that A. haemolyticum utilizes phospholipase D primarily for adherence and utilizes arcanolysin primarily for invasion into Detroit 562 cells in a process dependent on extracellular calcium and F-actin polymerization. Our work marks the first insight into how the individual activities of arcanolysin and phospholipase D affect A. haemolyticum host-pathogen interactions using the biologically relevant Detroit 562 cell line.
Collapse
|
23
|
Sharma AK, Leppla SH, Pomerantsev AP, Shiloach J. Effect of over expressing protective antigen on global gene transcription in Bacillus anthracis BH500. Sci Rep 2018; 8:16108. [PMID: 30382110 PMCID: PMC6208434 DOI: 10.1038/s41598-018-34196-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/08/2018] [Indexed: 01/22/2023] Open
Abstract
Protective antigen (PA) of Bacillus anthracis is being considered as a vaccine candidate against anthrax and its production has been explored in several heterologous host systems. Since the systems tested introduced adverse issues such as inclusion body formation and endotoxin contamination, the production from B. anthracis is considered as a preferred method. The present study examines the effect of PA expression on the metabolism of B. anthracis producing strain, BH500, by comparing it with a control strain carrying an empty plasmid. The strains were grown in a bioreactor and RNA-seq analysis of the producing and non-producing strain was conducted. Among the observed differences, the strain expressing rPA had increased transcription of sigL, the gene encoding RNA polymerase σ54, sigB, the general stress transcription factor gene and its regulators rsbW and rsbV, as well as the global regulatory repressor ctsR. There were also decreased expression of intracellular heat stress related genes such as groL, groES, hslO, dnaJ, and dnaK and increased expression of extracellular chaperons csaA and prsA2. Also, major central metabolism genes belonging to TCA, glycolysis, PPP, and amino acids biosynthesis were up-regulated in the PA-producing strain during the lag phase and down-regulated in the log and late-log phases, which was associated with decreased specific growth rates. The information obtained from this study may guide genetic modification of B. anthracis to improve PA production.
Collapse
Affiliation(s)
- Ashish K Sharma
- Biotechnology Core Laboratory, National Institute of Diabetes and Digestives and Kidney Diseases (NIDDK) NIH, Maryland, USA
| | - Stephen H Leppla
- Microbial Pathogenesis Section, National Institute of Allergy and Infectious diseases (NIAID), NIH, Maryland, USA
| | - Andrei P Pomerantsev
- Microbial Pathogenesis Section, National Institute of Allergy and Infectious diseases (NIAID), NIH, Maryland, USA
| | - Joseph Shiloach
- Biotechnology Core Laboratory, National Institute of Diabetes and Digestives and Kidney Diseases (NIDDK) NIH, Maryland, USA.
| |
Collapse
|
24
|
Arcanobacterium haemolyticum Phospholipase D Enzymatic Activity Promotes the Hemolytic Activity of the Cholesterol-Dependent Cytolysin Arcanolysin. Toxins (Basel) 2018; 10:toxins10060213. [PMID: 29882842 PMCID: PMC6024514 DOI: 10.3390/toxins10060213] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/14/2018] [Accepted: 05/18/2018] [Indexed: 02/06/2023] Open
Abstract
Arcanolysin, produced by the human pathogen Arcanobacterium haemolyticum, is a cholesterol-dependent cytolysin. To mediate the pore-formation process, arcanolysin is secreted by A. haemolyticum and then must interact with cholesterol embedded within a host membrane. However, arcanolysin must compete with membrane components, such as the phospholipid sphingomyelin, to interact with cholesterol and form pores. Cholesterol forms transient hydrogen bonds with the extracellular portion of sphingomyelin, shielding cholesterol from extracellular factors, including arcanolysin. A. haemolyticum also produces a sphingomyelin-specific phospholipase D, which removes the choline head from sphingomyelin, leaving cyclic-ceramide phosphate and eliminating the potential for cholesterol sequestration. We hypothesized that the enzymatic activity of phospholipase D decreases sphingomyelin-mediated cholesterol sequestration and increases cholesterol accessibility for arcanolysin. Using purified arcanolysin and phospholipase D, we demonstrate that the enzymatic activity of phospholipase D is necessary to promote arcanolysin-mediated hemolysis in both time- and concentration-dependent manners. Phospholipase D promotion of arcanolysin-mediated cytotoxicity was confirmed in Detroit 562 epithelial cells. Furthermore, we determined that incubating phospholipase D with erythrocytes corresponds with an increase in the amount of arcanolysin bound to host membranes. This observation suggests that phospholipase D promotes arcanolysin-mediated cytotoxicity by increasing the ability of arcanolysin to bind to a host membrane.
Collapse
|
25
|
Yang BW, Yeo IC, Choi JH, Sumi CD, Hahm YT. RNA-Seq Analysis of Antibiotic-Producing Bacillus subtilis SC-8 Reveals a Role for Small Peptides in Controlling PapR Signaling. Appl Biochem Biotechnol 2017; 185:359-369. [PMID: 29152694 DOI: 10.1007/s12010-017-2653-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 10/30/2017] [Indexed: 02/02/2023]
Abstract
Bacillus subtilis SC-8 (BSSC8) shows a narrow antimicrobial activity against the Bacillus cereus group. Previously, B. cereus-derived PapR as a signal peptide to stimulate PlcR, which plays a significant role in regulating the transcription of virulence factors, was assumed to stimulate antibiotic production in BSSC8. To better understand the functional role of PapR in the antibiotic production of BSSC8 and the interspecies interaction, the global transcriptomic profiling of BSSC8 was investigated using RNA-Seq in this study. Small peptides derived from B. cereus wild type (WTBC) and a papR-deleted mutant strain (MTBC) were individually supplied to BSSC8 cultures, and changes in global transcription levels were compared by RNA-Seq. In the presence of WTBC small peptides, more genes (80.9%) were significantly upregulated than in cells exposed to MTBC small peptides. Specifically, 48.8 and 83.4% of genes involved in glycolysis and the TCA cycle, respectively, showed changes in transcription levels in response to small peptides from both strains. Of the genes showing the alterations, 35.0% (glycolysis) and 60.0% (TCA cycle) of transcripts were significantly regulated only in response to WTBC-derived small peptides. Furthermore, the expression of biosynthetic genes encoding several known antibiotics in BSSC8 was further decreased in response to WTBC small peptides.
Collapse
Affiliation(s)
- Byung Wook Yang
- Department of Systems Biotechnology, Chung-Ang University, 4726, Seodong-daero, Anseong-si, Gyeonggi-do, 17546, Republic of Korea
| | - In-Cheol Yeo
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Jae Hee Choi
- Department of Systems Biotechnology, Chung-Ang University, 4726, Seodong-daero, Anseong-si, Gyeonggi-do, 17546, Republic of Korea
| | - Chandra Datta Sumi
- Department of Systems Biotechnology, Chung-Ang University, 4726, Seodong-daero, Anseong-si, Gyeonggi-do, 17546, Republic of Korea
| | - Young Tae Hahm
- Department of Systems Biotechnology, Chung-Ang University, 4726, Seodong-daero, Anseong-si, Gyeonggi-do, 17546, Republic of Korea.
| |
Collapse
|
26
|
Murakami C, Mizuno S, Kado S, Sakane F. Development of a liquid chromatography-mass spectrometry based enzyme activity assay for phosphatidylcholine-specific phospholipase C. Anal Biochem 2017; 526:43-49. [PMID: 28315318 DOI: 10.1016/j.ab.2017.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 02/24/2017] [Accepted: 03/13/2017] [Indexed: 01/01/2023]
Abstract
Phosphatidylcholine (PC)-specific phospholipase C (PC-PLC) hydrolyzes PC to generate the second messenger 1,2-diacylglycerol (DG) and phosphocholine. PC-PLC plays pivotal roles in inflammation, carcinogenesis, tumor progression, atherogenesis, and subarachnoid hemorrhage. Although the activity of PC-PLC in mammalian tissues was discovered approximately 40 years ago, neither the protein nor its gene has been identified. In the present study, we developed a non-radioactive enzyme activity assay for PC-PLC based on mass spectrometric detection of DG following HPLC separation. This new liquid chromatography-mass spectrometry (LC-MS) assay directly determines a specific reaction product, 1-palmitoyl-2-oleoyl-DG, that is generated from 1-palmitoyl-2-oleoyl-PC by purified Bacillus cereus PC-PLC. The LC-MS assay offers several advantages including a lower background (0.02% versus 91%), higher signal background ratio (4242 versus 1.06)/signal noise ratio (7494 versus 4.4), higher sensitivity (≥32-fold), and lower limit of quantitation (0.04 pmol versus 0.69 pmol of PC-PLC), than a conventional fluorometric assay, which indirectly detects phosphocholine produced in the reaction. In addition to Bacillus cereus PC-PLC, the LC-MS assay was applicable to the measurement of mammalian PC-PLC prepared from the mouse brain. The radioisotope-free, highly sensitive and precise LC-MS assay for PC-PLC would be useful for the purification and identification of PC-PLC protein.
Collapse
Affiliation(s)
- Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Satoru Mizuno
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Sayaka Kado
- Center for Analytical Instrumentation, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
| |
Collapse
|
27
|
In vivo characterization of an Hfq protein encoded by the Bacillus anthracis virulence plasmid pXO1. BMC Microbiol 2017; 17:63. [PMID: 28288571 PMCID: PMC5348863 DOI: 10.1186/s12866-017-0973-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 03/07/2017] [Indexed: 12/15/2022] Open
Abstract
Background Bacterial Hfq proteins post-transcriptionally regulate gene expression, primarily by mediating the interaction between sRNAs (small RNAs) and their target mRNAs. The role of Hfq-based regulation has been well defined in Gram-negative bacteria, but comparatively less is known about the impact of Hfq proteins in Gram-positive species. The Gram-positive pathogen Bacillus anthracis (causative agent of anthrax) is distinct in that it expresses three homologs of Hfq: Hfq1 and Hfq2 from the chromosome, and Hfq3 from the pXO1 virulence plasmid. Results In this study, we utilized overexpression as a strategy to examine the impact of Hfq3 on B. anthracis physiology. The increase in Hfq3 protein levels led to anomalous cell shape and chain formation, which manifested as a severe growth defect. This phenotype was specific to B. anthracis, as Hfq3 expression in B. subtilis at similar levels was not toxic. Toxicity was dependent on residues on the distal face of Hfq3 that are involved in mRNA binding in other bacterial species. Conclusions Thus, we hypothesize that Hfq3 interacts with RNA(s) involved in essential functions in the B. anthracis cell, leading to increased binding upon overexpression that either sequesters or accelerates degradation of RNAs important for growth. These results not only aid in elucidating the role of Hfq proteins in B. anthracis, but also contribute to our current understanding of Hfq in Gram-positive bacteria. Electronic supplementary material The online version of this article (doi:10.1186/s12866-017-0973-y) contains supplementary material, which is available to authorized users.
Collapse
|
28
|
AlMasoud N, Xu Y, Trivedi DK, Salivo S, Abban T, Rattray NJW, Szula E, AlRabiah H, Sayqal A, Goodacre R. Classification of Bacillus and Brevibacillus species using rapid analysis of lipids by mass spectrometry. Anal Bioanal Chem 2016; 408:7865-7878. [PMID: 27604269 PMCID: PMC5061856 DOI: 10.1007/s00216-016-9890-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 08/16/2016] [Indexed: 01/02/2023]
Abstract
Bacillus are aerobic spore-forming bacteria that are known to lead to specific diseases, such as anthrax and food poisoning. This study focuses on the characterization of these bacteria by the detection of lipids extracted from 33 well-characterized strains from the Bacillus and Brevibacillus genera, with the aim to discriminate between the different species. For the purpose of analysing the lipids extracted from these bacterial samples, two rapid physicochemical techniques were used: matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) and liquid chromatography in conjunction with mass spectrometry (LC-MS). The findings of this investigation confirmed that MALDI-TOF-MS could be used to identify different bacterial lipids and, in combination with appropriate chemometrics, allowed for the discrimination between these different bacterial species, which was supported by LC-MS. The average correct classification rates for the seven species of bacteria were 62.23 and 77.03 % based on MALDI-TOF-MS and LC-MS data, respectively. The Procrustes distance for the two datasets was 0.0699, indicating that the results from the two techniques were very similar. In addition, we also compared these bacterial lipid MALDI-TOF-MS profiles to protein profiles also collected by MALDI-TOF-MS on the same bacteria (Procrustes distance, 0.1006). The level of discrimination between lipids and proteins was equivalent, and this further indicated the potential of MALDI-TOF-MS analysis as a rapid, robust and reliable method for the classification of bacteria based on different bacterial chemical components. Graphical abstract MALDI-MS has been successfully developed for the characterization of bacteria at the subspecies level using lipids and benchmarked against HPLC.
Collapse
Affiliation(s)
- Najla AlMasoud
- School of Chemistry and Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Yun Xu
- School of Chemistry and Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Drupad K Trivedi
- School of Chemistry and Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Simona Salivo
- Shimadzu, Kratos Analytical Ltd. Wharfside, Trafford Wharf Road, Manchester, M17 1GP, UK
| | - Tom Abban
- Shimadzu, Kratos Analytical Ltd. Wharfside, Trafford Wharf Road, Manchester, M17 1GP, UK
| | - Nicholas J W Rattray
- School of Chemistry and Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Ewa Szula
- School of Chemistry and Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Haitham AlRabiah
- School of Chemistry and Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.,Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh, 11451, Saudi Arabia
| | - Ali Sayqal
- School of Chemistry and Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Royston Goodacre
- School of Chemistry and Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
| |
Collapse
|
29
|
The IntXO-PSL Recombination System Is a Key Component of the Second Maintenance System for Bacillus anthracis Plasmid pXO1. J Bacteriol 2016; 198:1939-1951. [PMID: 27137503 DOI: 10.1128/jb.01004-15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 04/25/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED We previously identified three noncontiguous regions on Bacillus anthracis plasmid pXO1 that comprise a system for accurate plasmid partitioning and maintenance. However, deletion of these regions did not decrease retention of certain shortened pXO1 plasmids during vegetative growth. Using two genetic tools developed for DNA manipulation in B. anthracis (the Cre-loxP and Flp-FRT systems), we found two other noncontiguous pXO1 regions that together are sufficient for plasmid stability. This second pXO1 maintenance system includes the tubZ and tubR genes, characteristic of a type III partitioning system, and the IntXO recombinase gene (GBAA_RS29165), encoding a tyrosine recombinase, along with its adjacent 37-bp perfect stem-loop (PSL) target. Insertion of either the tubZ and tubR genes or the IntXO-PSL system into an unstable mini-pXO1 plasmid did not restore plasmid stability. The need for the two components of the second pXO1 maintenance system follows from the sequential roles of IntXO-PSL in generating monomeric circular daughter pXO1 molecules (thereby presumably preventing dimer catastrophe) and of TubZ/TubR in partitioning the monomers during cell division. We show that the IntXO recombinase deletes DNA regions located between two PSL sites in a manner similar to the actions of the Cre-loxP and Flp-FRT systems. IMPORTANCE Tyrosine recombinases catalyze cutting and joining reactions between short specific DNA sequences. Three types of reactions occur: integration and excision of DNA segments, inversion of DNA segments, and separation of monomeric forms from replicating circular DNA molecules. Here we show that the newly discovered site-specific IntXO-PSL recombinase system that contributes to the maintenance of the B. anthracis plasmid pXO1 can be used for genome engineering in a manner similar to that of the Cre-loxP or Flp-FRT system.
Collapse
|
30
|
Abstract
Bacterial sphingomyelinases and phospholipases are a heterogeneous group of esterases which are usually surface associated or secreted by a wide variety of Gram-positive and Gram-negative bacteria. These enzymes hydrolyze sphingomyelin and glycerophospholipids, respectively, generating products identical to the ones produced by eukaryotic enzymes which play crucial roles in distinct physiological processes, including membrane dynamics, cellular signaling, migration, growth, and death. Several bacterial sphingomyelinases and phospholipases are essential for virulence of extracellular, facultative, or obligate intracellular pathogens, as these enzymes contribute to phagosomal escape or phagosomal maturation avoidance, favoring tissue colonization, infection establishment and progression, or immune response evasion. This work presents a classification proposal for bacterial sphingomyelinases and phospholipases that considers not only their enzymatic activities but also their structural aspects. An overview of the main physiopathological activities is provided for each enzyme type, as are examples in which inactivation of a sphingomyelinase- or a phospholipase-encoding gene impairs the virulence of a pathogen. The identification of sphingomyelinases and phospholipases important for bacterial pathogenesis and the development of inhibitors for these enzymes could generate candidate vaccines and therapeutic agents, which will diminish the impacts of the associated human and animal diseases.
Collapse
|
31
|
Celandroni F, Salvetti S, Senesi S, Ghelardi E. Bacillus thuringiensis membrane-damaging toxins acting on mammalian cells. FEMS Microbiol Lett 2014; 361:95-103. [PMID: 25283838 DOI: 10.1111/1574-6968.12615] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/26/2014] [Accepted: 09/29/2014] [Indexed: 01/20/2023] Open
Abstract
Bacillus thuringiensis is widely used as a biopesticide in forestry and agriculture, being able to produce potent species-specific insecticidal toxins and considered nonpathogenic to other animals. More recently, however, repeated observations are documenting the association of this microorganism with various infectious diseases in humans, such as food-poisoning-associated diarrheas, periodontitis, bacteremia, as well as ocular, burn, and wound infections. Similar to B. cereus, B. thuringiensis produces an array of virulence factors acting against mammalian cells, such as phosphatidylcholine- and phosphatidylinositol-specific phospholipase C (PC-PLC and PI-PLC), hemolysins, in particular hemolysin BL (HBL), and various enterotoxins. The contribution of some of these toxins to B. thuringiensis pathogenicity has been studied in animal models of infection, following intravitreous, intranasal, or intratracheal inoculation. These studies lead to the speculation that the activities of PC-PLC, PI-PLC, and HBL are responsible for most of the pathogenic properties of B. thuringiensis in nongastrointestinal infections in mammals. This review summarizes data regarding the biological activity, the genetic basis, and the structural features of these membrane-damaging toxins.
Collapse
Affiliation(s)
- Francesco Celandroni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | | | | | | |
Collapse
|
32
|
Identification of three noncontiguous regions on Bacillus anthracis plasmid pXO1 that are important for its maintenance. J Bacteriol 2014; 196:2921-33. [PMID: 24914182 DOI: 10.1128/jb.01747-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus anthracis pXO1 minireplicon (MR) plasmid consisting of open reading frames (ORFs) GBAA_pXO1_0020 to GBAA_pXO1_0023 is not stably maintained in B. anthracis, whereas the full-size parent pXO1 plasmid (having 181,677 bp and 217 ORFs) is extremely stable under the same growth conditions. Two genetic tools developed for DNA manipulation in B. anthracis (Cre-loxP and Flp-FRT systems) were used to identify pXO1 regions important for plasmid stability. We localized a large segment of pXO1 that enables stable plasmid maintenance during vegetative growth. Further genetic analysis identified three genes that are necessary for pXO1 maintenance: amsP (GBAA_pXO1_0069), minP (GBAA_pXO1_0082), and sojP (GBAA_pXO1_0084). Analysis of conserved domains in the corresponding proteins indicated that only AmsP (activator of maintenance system of pXO1) is predicted to bind DNA, due to its strong helix-turn-helix domain. Two conserved domains were found in the MinP protein (Min protein from pXO1): an N-terminal domain having some similarity to the B. anthracis septum site-determining protein MinD and a C-terminal domain that resembles a baculovirus single-stranded-DNA-binding protein. The SojP protein (Soj from pXO1) contains putative Walker box motifs and belongs to the ParA family of ATPases. No sequences encoding other components of type I plasmid partition systems, namely, cis-acting centromere parS and its binding ParB protein, were identified within the pXO1 genome. A model describing the role of the MinP protein in pXO1 distribution between daughter cells is proposed.
Collapse
|
33
|
Ghosh N, Goel AK, Alam SI. Exoproteome analysis of a novel strain of Bacillus cereus implicated in disease resembling cutaneous anthrax. INFECTION GENETICS AND EVOLUTION 2014; 22:1-11. [PMID: 24412723 DOI: 10.1016/j.meegid.2013.12.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 11/06/2013] [Accepted: 12/11/2013] [Indexed: 12/15/2022]
Abstract
Bacillus cereus belongs to B. cereus sensu lato group, shared by six other related species including Bacillus anthracis. B. anthracis is the causative agent for serious illness affecting a wide range of animals as well as humans and is a category A Biological and Toxin Warfare (BTW) agent. Recent studies indicate that a Bacillus species other than B. anthracis can cause anthrax-like disease and role of anthrax virulence plasmids (pXO1 and pXO2) on the pathogenicity of B. cereus has been documented. B. cereus strain TF5 was isolated from the tissue fluid of cutaneous anthrax-like skin lesions of a human patient from an anthrax endemic area in India. The strain harboured a PA gene, however, presence of pXO1 or pXO2-like plasmids could not be ascertained using reported primers. Abundant exoproteome of the strain in the early stationary phase was elucidated using a 2-DE MS approach and compared with that from a reference B. cereus strain. Analysis of proteins showing qualitative and quantitative differences between the two strains indicated an altered regulatory mechanism and putative role of S-layer protein and sphingomyelinase in the pathogenesis of strain TF5. Phylogenetic analysis of the S-layer protein indicated close affiliation of the strain with anthracis-like B. cereus strains such as B. cereus var. anthracis strain CI; whereas sphingomyelinase exhibited specific relationship with all the strains of B. anthracis apart from that with anthracis-like B. cereus strains.
Collapse
Affiliation(s)
- Neha Ghosh
- Biotechnology Division, Defence Research and Development Establishment, Gwalior 474002, India.
| | - Ajay Kumar Goel
- Biotechnology Division, Defence Research and Development Establishment, Gwalior 474002, India.
| | - Syed Imteyaz Alam
- Biotechnology Division, Defence Research and Development Establishment, Gwalior 474002, India.
| |
Collapse
|
34
|
Genetic evidence for the involvement of the S-layer protein gene sap and the sporulation genes spo0A, spo0B, and spo0F in Phage AP50c infection of Bacillus anthracis. J Bacteriol 2013; 196:1143-54. [PMID: 24363347 DOI: 10.1128/jb.00739-13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
In order to better characterize the Bacillus anthracis typing phage AP50c, we designed a genetic screen to identify its bacterial receptor. Insertions of the transposon mariner or targeted deletions of the structural gene for the S-layer protein Sap and the sporulation genes spo0A, spo0B, and spo0F in B. anthracis Sterne resulted in phage resistance with concomitant defects in phage adsorption and infectivity. Electron microscopy of bacteria incubated with AP50c revealed phage particles associated with the surface of bacilli of the Sterne strain but not with the surfaces of Δsap, Δspo0A, Δspo0B, or Δspo0F mutants. The amount of Sap in the S layer of each of the spo0 mutant strains was substantially reduced compared to that of the parent strain, and incubation of AP50c with purified recombinant Sap led to a substantial reduction in phage activity. Phylogenetic analysis based on whole-genome sequences of B. cereus sensu lato strains revealed several closely related B. cereus and B. thuringiensis strains that carry sap genes with very high similarities to the sap gene of B. anthracis. Complementation of the Δsap mutant in trans with the wild-type B. anthracis sap or the sap gene from either of two different B. cereus strains that are sensitive to AP50c infection restored phage sensitivity, and electron microscopy confirmed attachment of phage particles to the surface of each of the complemented strains. Based on these data, we postulate that Sap is involved in AP50c infectivity, most likely acting as the phage receptor, and that the spo0 genes may regulate synthesis of Sap and/or formation of the S layer.
Collapse
|
35
|
Sastalla I, Fattah R, Coppage N, Nandy P, Crown D, Pomerantsev AP, Leppla SH. The Bacillus cereus Hbl and Nhe tripartite enterotoxin components assemble sequentially on the surface of target cells and are not interchangeable. PLoS One 2013; 8:e76955. [PMID: 24204713 PMCID: PMC3799921 DOI: 10.1371/journal.pone.0076955] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 08/28/2013] [Indexed: 02/06/2023] Open
Abstract
Bacillus cereus is a spore-forming, Gram-positive bacterium commonly associated with outbreaks of food poisoning. It is also known as an opportunistic pathogen causing clinical infections such as bacteremia, meningitis, pneumonia, and gas gangrene-like cutaneous infections, mostly in immunocompromised patients. B. cereus secretes a plethora of toxins of which four are associated with the symptoms of food poisoning. Two of these, the non-hemolytic enterotoxin Nhe and the hemolysin BL (Hbl) toxin, are predicted to be structurally similar and are unique in that they require the combined action of three toxin proteins to induce cell lysis. Despite their dominant role in disease, the molecular mechanism of their toxic function is still poorly understood. We report here that B. cereus strain ATCC 10876 harbors not only genes encoding Nhe, but also two copies of the hbl genes. We identified Hbl as the major secreted toxin responsible for inducing rapid cell lysis both in cultured cells and in an intraperitoneal mouse toxicity model. Antibody neutralization and deletion of Hbl-encoding genes resulted in significant reductions of cytotoxic activity. Microscopy studies with Chinese Hamster Ovary cells furthermore showed that pore formation by both Hbl and Nhe occurs through a stepwise, sequential binding of toxin components to the cell surface and to each other. This begins with binding of Hbl-B or NheC to the eukaryotic membrane, and is followed by the recruitment of Hbl-L1 or NheB, respectively, followed by the corresponding third protein. Lastly, toxin component complementation studies indicate that although Hbl and Nhe can be expressed simultaneously and are predicted to be structurally similar, they are incompatible and cannot complement each other.
Collapse
Affiliation(s)
- Inka Sastalla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| | - Rasem Fattah
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nicole Coppage
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Poulomi Nandy
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Devorah Crown
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Andrei P. Pomerantsev
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Stephen H. Leppla
- Microbial Pathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| |
Collapse
|
36
|
Rendón-Ramírez A, Shukla M, Oda M, Chakraborty S, Minda R, Dandekar AM, Ásgeirsson B, Goñi FM, Rao BJ. A computational module assembled from different protease family motifs identifies PI PLC from Bacillus cereus as a putative prolyl peptidase with a serine protease scaffold. PLoS One 2013; 8:e70923. [PMID: 23940667 PMCID: PMC3733634 DOI: 10.1371/journal.pone.0070923] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 06/28/2013] [Indexed: 12/12/2022] Open
Abstract
Proteolytic enzymes have evolved several mechanisms to cleave peptide bonds. These distinct types have been systematically categorized in the MEROPS database. While a BLAST search on these proteases identifies homologous proteins, sequence alignment methods often fail to identify relationships arising from convergent evolution, exon shuffling, and modular reuse of catalytic units. We have previously established a computational method to detect functions in proteins based on the spatial and electrostatic properties of the catalytic residues (CLASP). CLASP identified a promiscuous serine protease scaffold in alkaline phosphatases (AP) and a scaffold recognizing a β-lactam (imipenem) in a cold-active Vibrio AP. Subsequently, we defined a methodology to quantify promiscuous activities in a wide range of proteins. Here, we assemble a module which encapsulates the multifarious motifs used by protease families listed in the MEROPS database. Since APs and proteases are an integral component of outer membrane vesicles (OMV), we sought to query other OMV proteins, like phospholipase C (PLC), using this search module. Our analysis indicated that phosphoinositide-specific PLC from Bacillus cereus is a serine protease. This was validated by protease assays, mass spectrometry and by inhibition of the native phospholipase activity of PI-PLC by the well-known serine protease inhibitor AEBSF (IC50 = 0.018 mM). Edman degradation analysis linked the specificity of the protease activity to a proline in the amino terminal, suggesting that the PI-PLC is a prolyl peptidase. Thus, we propose a computational method of extending protein families based on the spatial and electrostatic congruence of active site residues.
Collapse
Affiliation(s)
- Adela Rendón-Ramírez
- Unidad de Biofísica (Consejo Superior de Investigaciones Científicas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Manish Shukla
- Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, India
| | - Masataka Oda
- Department of Microbiology, Faculty of Pharmaceutical Science, Tokushima Bunri University, Tokushima, Japan
| | - Sandeep Chakraborty
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
- * E-mail:
| | - Renu Minda
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Abhaya M. Dandekar
- Plant Sciences Department, University of California, Davis, Davis, California, United States of America
| | - Bjarni Ásgeirsson
- Science Institute, Department of Biochemistry, University of Iceland, Dunhaga, Reykjavik, Iceland
| | - Félix M. Goñi
- Unidad de Biofísica (Consejo Superior de Investigaciones Científicas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain
| | - Basuthkar J. Rao
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| |
Collapse
|
37
|
Manos J, Hu H, Rose BR, Wainwright CE, Zablotska IB, Cheney J, Turnbull L, Whitchurch CB, Grimwood K, Harmer C, Anuj SN, Harbour C. Virulence factor expression patterns in Pseudomonas aeruginosa strains from infants with cystic fibrosis. Eur J Clin Microbiol Infect Dis 2013; 32:1583-92. [DOI: 10.1007/s10096-013-1916-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 06/17/2013] [Indexed: 12/16/2022]
|
38
|
Doll VM, Ehling-Schulz M, Vogelmann R. Concerted action of sphingomyelinase and non-hemolytic enterotoxin in pathogenic Bacillus cereus. PLoS One 2013; 8:e61404. [PMID: 23613846 PMCID: PMC3628865 DOI: 10.1371/journal.pone.0061404] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 03/10/2013] [Indexed: 11/18/2022] Open
Abstract
Bacillus cereus causes food poisoning and serious non-gastrointestinal-tract infections. Non-hemolytic enterotoxin (Nhe), which is present in most B. cereus strains, is considered to be one of the main virulence factors. However, a B. cereus ΔnheBC mutant strain lacking Nhe is still cytotoxic to intestinal epithelial cells. In a screen for additional cytotoxic factors using an in vitro model for polarized colon epithelial cells we identified B. cereus sphingomyelinase (SMase) as a strong inducer of epithelial cell death. Using single and double deletion mutants of sph, the gene encoding for SMase, and nheBC in B. cereus we demonstrated that SMase is an important factor for B. cereus cytotoxicity in vitro and pathogenicity in vivo. SMase substantially complemented Nhe induced cytotoxicity in vitro. In addition, SMase but not Nhe contributed significantly to the mortality rate of larvae in vivo in the insect model Galleria mellonella. Our study suggests that the role of B. cereus SMase as a secreted virulence factor for in vivo pathogenesis has been underestimated and that Nhe and SMase complement each other significantly to cause full B. cereus virulence hence disease formation.
Collapse
Affiliation(s)
- Viktoria M. Doll
- Abteilung Mikrobiologie, Zentralinstitut für Ernährungs- und Lebensmittelforschung ZIEL, Technische Universität München, Freising Weihenstephan, Germany
| | - Monika Ehling-Schulz
- Functional Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Roger Vogelmann
- Second Department of Internal Medicine, Universitätsmedizin Mannheim, University Heidelberg, Mannheim, Germany
- * E-mail:
| |
Collapse
|
39
|
Bishop-Lilly KA, Plaut RD, Chen PE, Akmal A, Willner KM, Butani A, Dorsey S, Mokashi V, Mateczun AJ, Chapman C, George M, Luu T, Read TD, Calendar R, Stibitz S, Sozhamannan S. Whole genome sequencing of phage resistant Bacillus anthracis mutants reveals an essential role for cell surface anchoring protein CsaB in phage AP50c adsorption. Virol J 2012; 9:246. [PMID: 23098174 PMCID: PMC3545897 DOI: 10.1186/1743-422x-9-246] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 10/24/2012] [Indexed: 01/12/2023] Open
Abstract
Background Spontaneous Bacillus anthracis mutants resistant to infection by phage AP50c (AP50R) exhibit a mucoid colony phenotype and secrete an extracellular matrix. Methods Here we utilized a Roche/454-based whole genome sequencing approach to identify mutations that are candidates for conferring AP50c phage resistance, followed by genetic deletion and complementation studies to validate the whole genome sequence data and demonstrate that the implicated gene is necessary for AP50c phage infection. Results Using whole genome sequence data, we mapped the relevant mutations in six AP50R strains to csaB. Eleven additional spontaneous mutants, isolated in two different genetic backgrounds, were screened by PCR followed by Sanger sequencing of the csaB gene. In each spontaneous mutant, we found either a non-synonymous substitution, a nonsense mutation, or a frame-shift mutation caused by single nucleotide polymorphisms or a 5 base pair insertion in csaB. All together, 5 and 12 of the 17 spontaneous mutations are predicted to yield altered full length and truncated CsaB proteins respectively. As expected from these results, a targeted deletion or frame-shift mutations introduced into csaB in a different genetic background, in a strain not exposed to AP50c, resulted in a phage resistant phenotype. Also, substitution of a highly conserved histidine residue with an alanine residue (H270A) in CsaB resulted in phage resistance, suggesting that a functional CsaB is necessary for phage sensitivity. Conversely, introduction of the wild type allele of csaB in cis into the csaB deletion mutant by homologous recombination or supplying the wild type CsaB protein in trans from a plasmid restored phage sensitivity. The csaB mutants accumulated cell wall material and appeared to have a defective S-layer, whereas these phenotypes were reverted in the complemented strains. Conclusions Taken together, these data suggest an essential role for csaB in AP50c phage infection, most likely in phage adsorption. (The whole genome sequences generated from this study have been submitted to GenBank under SRA project ID: SRA023659.1 and sample IDs: AP50 R1: SRS113675.1, AP50 R2: SRS113676.1, AP50 R3: SRS113728.1, AP50 R4: SRS113733.1, AP50 R6: SRS113734.1, JB220 Parent: SRS150209.1, JB220 Mutant: SRS150211.1).
Collapse
|
40
|
Frenzel E, Doll V, Pauthner M, Lücking G, Scherer S, Ehling-Schulz M. CodY orchestrates the expression of virulence determinants in emetic Bacillus cereus by impacting key regulatory circuits. Mol Microbiol 2012; 85:67-88. [PMID: 22571587 DOI: 10.1111/j.1365-2958.2012.08090.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Bacillus cereus causes gastrointestinal diseases and local and systemic infections elicited by the depsipeptide cereulide, enterotoxins, phospholipases, cytolysins and proteases. The PlcR-PapR quorum sensing system activates the expression of several virulence factors, whereas the Spo0A-AbrB regulatory circuit partially controls the plasmid-borne cereulide synthetase (ces) operon. Here, we show that CodY, a nutrient-responsive regulator of Gram-positive bacteria, has a profound effect on both regulatory systems, which have been assumed to operate independently of each other. Deletion of codY resulted in downregulation of virulence genes belonging to the PlcR regulon and a concomitant upregulation of the ces genes. CodY was found to be a repressor of the ces operon, but did not interact with the promoter regions of PlcR-dependent virulence genes in vitro, suggesting an indirect regulation of the latter. Furthermore, CodY binds to the promoter of the immune inhibitor metalloprotease InhA1, demonstrating that CodY directly links B. cereus metabolism to virulence. In vivo studies using a Galleria mellonella infection model, showed that the codY mutant was substantially attenuated, highlighting the importance of CodY as a key regulator of pathogenicity. Our results demonstrate that CodY profoundly modulates the virulence of B. cereus, possibly controlling the development of pathogenic traits in suitable host environments.
Collapse
Affiliation(s)
- Elrike Frenzel
- Institute of Functional Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | | | | | | | | | | |
Collapse
|
41
|
Gu C, Jenkins SA, Xue Q, Xu Y. Activation of the classical complement pathway by Bacillus anthracis is the primary mechanism for spore phagocytosis and involves the spore surface protein BclA. THE JOURNAL OF IMMUNOLOGY 2012; 188:4421-31. [PMID: 22442442 DOI: 10.4049/jimmunol.1102092] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Interactions between spores of Bacillus anthracis and macrophages are critical for the development of anthrax infections, as spores are thought to use macrophages as vehicles to disseminate in the host. In this study, we report a novel mechanism for phagocytosis of B. anthracis spores. Murine macrophage-like cell line RAW264.7, bone marrow-derived macrophages, and primary peritoneal macrophages from mice were used. The results indicated that activation of the classical complement pathway (CCP) was a primary mechanism for spore phagocytosis. Phagocytosis was significantly reduced in the absence of C1q or C3. C3 fragments were found deposited on the spore surface, and the deposition was dependent on C1q and Ca(2+). C1q recruitment to the spore surface was mediated by the spore surface protein BclA, as recombinant BclA bound directly and specifically to C1q and inhibited C1q binding to spores in a dose-dependent manner. C1q binding to spores lacking BclA (ΔbclA) was also significantly reduced compared with wild-type spores. In addition, deposition of both C3 and C4 as well as phagocytosis of spores were significantly reduced when BclA was absent, but were not reduced in the absence of IgG, suggesting that BclA, but not IgG, is important in these processes. Taken together, these results support a model in which spores actively engage CCP primarily through BclA interaction with C1q, leading to CCP activation and opsonophagocytosis of spores in an IgG-independent manner. These findings are likely to have significant implications on B. anthracis pathogenesis and microbial manipulation of complement.
Collapse
Affiliation(s)
- Chunfang Gu
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | | | | | | |
Collapse
|
42
|
Santos C, Almeida F, Guimarães A, Abrahão W, Arantes O, Vilas-Bôas G. RE-PCR variability and toxigenic profile of food poisoning, foodborne and soil-associated Bacillus cereus isolates from Brazil. Int J Food Microbiol 2011; 151:277-83. [DOI: 10.1016/j.ijfoodmicro.2011.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 07/25/2011] [Accepted: 09/11/2011] [Indexed: 11/25/2022]
|
43
|
Li H, Zhang L, Yin D, Zhang Y, Miao J. Targeting phosphatidylcholine-specific phospholipase C for atherogenesis therapy. Trends Cardiovasc Med 2011; 20:172-6. [PMID: 21742273 DOI: 10.1016/j.tcm.2011.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Atherosclerosis, a dynamic and progressive vascular disease arising from the combination of endothelial dysfunction and inflammation, is becoming a major killer in the 21st century. Accumulating evidence implicates phosphatidylcholine-specific phospholipase C (PC-PLC) in endothelial dysfunction and several inflammation processes. In addition, in a recent study, we demonstrated that PC-PLC contributed to the progression of atherosclerosis. Considering the important roles of PC-PLC in vascular endothelial cell dysfunction and its proinflammatory properties, we propose that a pharmacological blockade of PC-PLC represents a rational approach to atherosclerosis therapy.
Collapse
Affiliation(s)
- HaiYing Li
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100, China
| | | | | | | | | |
Collapse
|
44
|
A Bacillus anthracis strain deleted for six proteases serves as an effective host for production of recombinant proteins. Protein Expr Purif 2011; 80:80-90. [PMID: 21827967 DOI: 10.1016/j.pep.2011.05.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 05/23/2011] [Indexed: 12/25/2022]
Abstract
Bacillus anthracis produces a number of extracellular proteases that impact the integrity and yield of other proteins in the B. anthracis secretome. In this study we show that anthrolysin O (ALO) and the three anthrax toxin proteins, protective antigen (PA), lethal factor (LF), and edema factor (EF), produced from the B. anthracis Ames 35 strain (pXO1⁺, pXO2⁻), are completely degraded at the onset of stationary phase due to the action of proteases. An improved Cre-loxP gene knockout system was used to sequentially delete the genes encoding six proteases (InhA1, InhA2, camelysin, TasA, NprB, and MmpZ). The role of each protease in degradation of the B. anthracis toxin components and ALO was demonstrated. Levels of the anthrax toxin components and ALO in the supernatant of the sporulation defective, pXO1⁺ A35HMS mutant strain deleted for the six proteases were significantly increased and remained stable over 24 h. A pXO1-free variant of this six-protease mutant strain, designated BH460, provides an improved host strain for the preparation of recombinant proteins. As an example, BH460 was used to produce recombinant EF, which previously has been difficult to obtain from B. anthracis. The EF protein produced from BH460 had the highest in vivo potency of any EF previously purified from B. anthracis or Escherichia coli hosts. BH460 is recommended as an effective host strain for recombinant protein production, typically yielding greater than 10mg pure protein per liter of culture.
Collapse
|
45
|
Wargo MJ, Gross MJ, Rajamani S, Allard JL, Lundblad LKA, Allen GB, Vasil ML, Leclair LW, Hogan DA. Hemolytic phospholipase C inhibition protects lung function during Pseudomonas aeruginosa infection. Am J Respir Crit Care Med 2011; 184:345-54. [PMID: 21562128 DOI: 10.1164/rccm.201103-0374oc] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
RATIONALE The opportunistic pathogen Pseudomonas aeruginosa causes both acute and chronic lung infections and is particularly problematic in patients with cystic fibrosis and those undergoing mechanical ventilation. Decreased lung function contributes significantly to morbidity and mortality during P. aeruginosa infection, and damage inflicted by P. aeruginosa virulence factors contributes to lung function decline. OBJECTIVES We sought to describe direct contribution of a bacterial phospholipase C/sphingomyelinase, PlcHR, to alteration of host lung physiology and characterize a potential therapeutic for protection of lung function. METHODS We infected C57Bl/6 mice with P. aeruginosa wild-type or isogenic plcHR deletion strains and measured lung function using computer-controlled ventilators. For in vivo testing, miltefosine was delivered intraperitoneally 1 hour after infection. Infection and respiratory endpoints were at 24 hours after infection. MEASUREMENTS AND MAIN RESULTS P. aeruginosa wild-type infection caused significant lung function impairment, whereas the effects of a ΔplcHR strain infection were much less severe. Surfactometry analysis of bronchoalveolar lavage fluid indicated that PlcHR decreased pulmonary surfactant function. Miltefosine has structural similarity to the PC and sphingomyelin substrates of PlcHR, and we found that it inhibits the cleavage of these choline-containing lipids in vitro. Miltefosine administration after P. aeruginosa infection limited the negative effects of PlcHR activity on lung function. CONCLUSIONS We have directly linked production of a single virulence factor in P. aeruginosa with effects on lung function, and demonstrated that the inhibitor miltefosine protects lung function from PlcHR-dependent surfactant dysfunction.
Collapse
Affiliation(s)
- Matthew J Wargo
- Department of Microbiology and Molecular Genetics, University of Vermont College of Medicine, Burlington, VT 05405, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Sastalla I, Maltese LM, Pomerantseva OM, Pomerantsev AP, Keane-Myers A, Leppla SH. Activation of the latent PlcR regulon in Bacillus anthracis. MICROBIOLOGY-SGM 2010; 156:2982-2993. [PMID: 20688829 PMCID: PMC3068694 DOI: 10.1099/mic.0.041418-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Many genes in Bacillus cereus and Bacillus thuringiensis are under the control of the transcriptional regulator PlcR and its regulatory peptide, PapR. In Bacillus anthracis, the causative agent of anthrax, PlcR is inactivated by truncation, and consequently genes having PlcR binding sites are expressed at very low levels when compared with B. cereus. We found that activation of the PlcR regulon in B. anthracis by expression of a PlcR–PapR fusion protein does not alter sporulation in strains containing the virulence plasmid pXO1 and thereby the global regulator AtxA. Using comparative 2D gel electrophoresis, we showed that activation of the PlcR regulon in B. anthracis leads to upregulation of many proteins found in the secretome of B. cereus, including phospholipases and proteases, such as the putative protease BA1995. Transcriptional analysis demonstrated expression of BA1995 to be dependent on PlcR–PapR, even though the putative PlcR recognition site of the BA1995 gene does not exactly match the PlcR consensus sequence, explaining why this protein had escaped recognition as belonging to the PlcR regulon. Additionally, while transcription of major PlcR-dependent haemolysins, sphingomyelinase and anthrolysin O is enhanced in response to PlcR activation in B. anthracis, only anthrolysin O contributes significantly to lysis of human erythrocytes. In contrast, the toxicity of bacterial culture supernatants from a PlcR-positive strain towards murine macrophages occurred independently of anthrolysin O expression in vitro and in vivo.
Collapse
Affiliation(s)
- Inka Sastalla
- Laboratory of Bacterial Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Lauren M Maltese
- Laboratory of Bacterial Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Olga M Pomerantseva
- Biological Defense Research Directorate, Naval Medical Research Center, Rockville, MD, USA
| | - Andrei P Pomerantsev
- Laboratory of Bacterial Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Andrea Keane-Myers
- Biological Defense Research Directorate, Naval Medical Research Center, Rockville, MD, USA
| | - Stephen H Leppla
- Laboratory of Bacterial Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
47
|
Mohan H, Maheswari KU, Bera AK, Suraishkumar G. Reactive oxygen species mediated modifications in Bacillus subtilis lipid membrane to improve protein productivities. Process Biochem 2010. [DOI: 10.1016/j.procbio.2009.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
48
|
Abstract
An 8,883-bp mini-pXO1 plasmid containing a replicon from Bacillus anthracis pXO1 (181.6 kb) was identified by making large deletions in the original plasmid using a newly developed Cre-loxP system. Portions of the truncated mini-pXO1 were cloned into an Escherichia coli vector unable to replicate in B. anthracis. A 5.95-kb region encompassing three putative genes was identified as the minimal pXO1 fragment required for replication of the resulting recombinant shuttle plasmid (named pMR) in B. anthracis. Deletion analysis showed that the only genes essential for replication were the pXO1-14 and pXO1-16 genes, which are transcribed in opposite directions and encode predicted proteins of 66.5 and 67.1 kDa, respectively. The ORF14 protein contains a helix-turn-helix motif, while the ORF16 upstream region contains attributes of a theta-replicating plasmid origin of replication (Ori), namely, an exclusively A+T-containing segment, five 9-bp direct repeats, an inverted repeat, and a sigma(A)-dependent promoter for the putative replication initiator Rep protein (ORF16). Spontaneous mutations generated in the ORF14, ORF16, and Ori regions of pMR during PCR amplification produced a temperature-sensitive plasmid that is unable to replicate in B. anthracis at 37 degrees C. The efficacy of transformation of plasmid-free B. anthracis Ames and Sterne strains by the original pMR was approximately 10(3) CFU/microg, while Bacillus cereus strains 569 and ATCC 10987 were transformed with efficiencies of 10(4) and 10(2) CFU/microg, respectively. Around 95% of B. anthracis cells retained pMR after one round of sporulation and germination.
Collapse
|
49
|
Didelot X, Barker M, Falush D, Priest FG. Evolution of pathogenicity in the Bacillus cereus group. Syst Appl Microbiol 2009; 32:81-90. [PMID: 19200684 DOI: 10.1016/j.syapm.2009.01.001] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 01/06/2009] [Accepted: 01/07/2009] [Indexed: 11/25/2022]
Abstract
The Bacillus cereus group of bacteria comprises soil-dwelling saprophytes but on occasion these bacteria can cause a wide range of diseases in humans, including food poisoning, systemic infections and highly lethal forms of anthrax. While anthrax is almost invariably caused by strains from a single evolutionary lineage, Bacillus anthracis, variation in the virulence properties of strains from other lineages has not been fully addressed. Using multi-locus sequence data from 667 strains, we reconstructed the evolutionary history of the B. cereus group in terms of both clonal inheritance and recombination. The strains included 155 clinical isolates representing B. anthracis, and isolates from emetic and diarrhoeal food poisoning, septicaemia and related infections, wound, and lung infections. We confirmed the existence of three major clades and found that clinical isolates of B. cereus (with the exception of emetic toxin-producing strains) are evenly distributed between and within clades 1 and 2. B. anthracis in particular and emetic toxin-producing B. cereus show more clonal structure and are restricted to clade 1. Our characterization of the patterns of genetic exchange showed that there exist partial barriers to gene flow between the three clades. The pathogenic strains do not exhibit atypically high or low rates of recombination, consistent with the opportunistic nature of most pathogenic infections. However, there have been a large number of recent imports in clade 1 of strains from external origins, which is indicative of an on-going shift in gene-flow boundaries for this clade.
Collapse
Affiliation(s)
- Xavier Didelot
- Department of Statistics, University of Warwick, Coventry CV4 7AL, UK.
| | | | | | | |
Collapse
|
50
|
Codon-optimized fluorescent proteins designed for expression in low-GC gram-positive bacteria. Appl Environ Microbiol 2009; 75:2099-110. [PMID: 19181829 DOI: 10.1128/aem.02066-08] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Fluorescent proteins have wide applications in biology. However, not all of these proteins are properly expressed in bacteria, especially if the codon usage and genomic GC content of the host organism are not ideal for high expression. In this study, we analyzed the DNA sequences of multiple fluorescent protein genes with respect to codons and GC content and compared them to a low-GC gram-positive bacterium, Bacillus anthracis. We found high discrepancies for cyan fluorescent protein (CFP), yellow fluorescent protein (YFP), and the photoactivatable green fluorescent protein (PAGFP), but not GFP, with regard to GC content and codon usage. Concomitantly, when the proteins were expressed in B. anthracis, CFP- and YFP-derived fluorescence was undetectable microscopically, a phenomenon caused not by lack of gene transcription or degradation of the proteins but by lack of protein expression. To improve expression in bacteria with low genomic GC contents, we synthesized a codon-optimized gfp and constructed optimized photoactivatable pagfp, cfp, and yfp, which were in contrast to nonoptimized genes highly expressed in B. anthracis and in another low-GC gram-positive bacterium, Staphylococcus aureus. Using optimized GFP as a reporter, we were able to monitor the activity of the protective antigen promoter of B. anthracis and confirm its dependence on bicarbonate and regulators present on virulence plasmid pXO1.
Collapse
|