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Pore-forming proteins: From defense factors to endogenous executors of cell death. Chem Phys Lipids 2020; 234:105026. [PMID: 33309552 DOI: 10.1016/j.chemphyslip.2020.105026] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 12/07/2020] [Accepted: 12/07/2020] [Indexed: 02/06/2023]
Abstract
Pore-forming proteins (PFPs) and small antimicrobial peptides (AMPs) represent a large family of molecules with the common ability to punch holes in cell membranes to alter their permeability. They play a fundamental role as infectious bacteria's defensive tools against host's immune system and as executors of endogenous machineries of regulated cell death in eukaryotic cells. Despite being highly divergent in primary sequence and 3D structure, specific folds of pore-forming domains have been conserved. In fact, pore formation is considered an ancient mechanism that takes place through a general multistep process involving: membrane partitioning and insertion, oligomerization and pore formation. However, different PFPs and AMPs assemble and form pores following different mechanisms that could end up either in the formation of protein-lined or protein-lipid pores. In this review, we analyze the current findings in the mechanism of action of different PFPs and AMPs that support a wide role of membrane pore formation in nature. We also provide the newest insights into the development of state-of-art techniques that have facilitated the characterization of membrane pores. To understand the physiological role of these peptides/proteins or develop clinical applications, it is essential to uncover the molecular mechanism of how they perforate membranes.
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Lee SC, Yoon MY. Development of a receptor-based inhibitory penta-unit-conjugated peptide to enhance anthrax toxin neutralization. Int J Biol Macromol 2020; 163:327-335. [PMID: 32619663 DOI: 10.1016/j.ijbiomac.2020.06.264] [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: 04/25/2020] [Revised: 06/26/2020] [Accepted: 06/28/2020] [Indexed: 12/21/2022]
Abstract
Anthrax toxin is a key virulence factor for Bacillus anthracis. The cell-binding component of anthrax toxin, protective antigen (PA), mediates the entry of the toxin into cells by first binding to the extracellular von Willebrand factor A (VWA) domain of the cellular anthrax toxin receptor (ATR). Herein, we targeted the VWA domain of the cellular receptor to develop a more effective antitoxin agent for neutralization of anthrax toxin. We selected ATR-binding peptides by using a phage display: among these, we identified two novel peptides binding to the ATR with high affinity and specificity, and that neutralized anthrax toxicity in cells. Furthermore, to enhance the functional efficiency of the probes, the peptides were modified and conjugated to three polyvalent probe backbones: a 17 amino-acid-based cyclic form penta-unit, poly-d-lysine (PDL), or the M13 bacteriophage. One of the functionally modified polyvalent peptide probes, the penta-unit-conjugated probe (PUCP) produced the most potent neutralization of anthrax toxin, with half-maximal inhibitory concentration (IC50) of 20 nM. The PUCP disrupted anthrax toxin binding to its receptor and reduced endocytosis of anthrax toxin. This peptide-based approach may, therefore, represent a promising strategy to combat anthrax toxicosis and other bacterial diseases and may be efficient for disease treatment.
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Affiliation(s)
- Sang-Choon Lee
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA.
| | - Moon-Young Yoon
- Department of Chemistry and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea.
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Secaira-Morocho H, Castillo JA, Driks A. Diversity and evolutionary dynamics of spore-coat proteins in spore-forming species of Bacillales. Microb Genom 2020; 6. [PMID: 33052805 PMCID: PMC7725329 DOI: 10.1099/mgen.0.000451] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Among members of the Bacillales order, there are several species capable of forming a structure called an endospore. Endospores enable bacteria to survive under unfavourable growth conditions and germinate when environmental conditions are favourable again. Spore-coat proteins are found in a multilayered proteinaceous structure encasing the spore core and the cortex. They are involved in coat assembly, cortex synthesis and germination. Here, we aimed to determine the diversity and evolutionary processes that have influenced spore-coat genes in various spore-forming species of Bacillales using an in silico approach. For this, we used sequence similarity searching algorithms to determine the diversity of coat genes across 161 genomes of Bacillales. The results suggest that among Bacillales, there is a well-conserved core genome, composed mainly by morphogenetic coat proteins and spore-coat proteins involved in germination. However, some spore-coat proteins are taxa-specific. The best-conserved genes among different species may promote adaptation to changeable environmental conditions. Because most of the Bacillus species harbour complete or almost complete sets of spore-coat genes, we focused on this genus in greater depth. Phylogenetic reconstruction revealed eight monophyletic groups in the Bacillus genus, of which three are newly discovered. We estimated the selection pressures acting over spore-coat genes in these monophyletic groups using classical and modern approaches and detected horizontal gene transfer (HGT) events, which have been further confirmed by scanning the genomes to find traces of insertion sequences. Although most of the genes are under purifying selection, there are several cases with individual sites evolving under positive selection. Finally, the HGT results confirm that sporulation is an ancestral feature in Bacillus.
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Affiliation(s)
- Henry Secaira-Morocho
- School of Biological Sciences and Engineering, Yachay Tech University, San Miguel de Urcuquí, Imbabura, Ecuador
| | - José A Castillo
- School of Biological Sciences and Engineering, Yachay Tech University, San Miguel de Urcuquí, Imbabura, Ecuador
| | - Adam Driks
- Department of Microbiology and Immunology, Loyola University Chicago, Chicago, IL, USA
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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: 56] [Impact Index Per Article: 14.0] [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.
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Lawrence WS, Peel JE, Sivasubramani SK, Baze WB, Whorton EB, Beasley DWC, Comer JE, Hughes DE, Ling LL, Peterson JW. Teixobactin Provides Protection against Inhalation Anthrax in the Rabbit Model. Pathogens 2020; 9:pathogens9090773. [PMID: 32971758 PMCID: PMC7558628 DOI: 10.3390/pathogens9090773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 01/20/2023] Open
Abstract
The use of antibiotics is a vital means of treating infections caused by the bacteria Bacillus (B.) anthracis. Importantly, with the potential future use of multidrug-resistant strains of B. anthracis as bioweapons, new antibiotics are needed as alternative therapeutics. In this blinded study, we assessed the protective efficacy of teixobactin, a recently discovered antibiotic, against inhalation anthrax infection in the adult rabbit model. New Zealand White rabbits were infected with a lethal dose of B. anthracis Ames spores via the inhalation route, and blood samples were collected at various times to assess antigenemia, bacteremia, tissue bacterial load, and antibody production. Treatments were administered upon detection of B. anthracis protective antigen in the animals’ sera. For comparison, a fully protective dose of levofloxacin was used as a positive control. Rabbits treated with teixobactin showed 100% survival following infection, and the bacteremia was completely resolved by 24–48 h post-treatment. In addition, the bacterial/spore loads in tissues of the animals treated with teixobactin were either zero or dramatically less relative to that of the negative control animals. Moreover, microscopic evaluation of the tissues revealed decreased pathology following treatment with teixobactin. Overall, these results show that teixobactin was protective against inhalation anthrax infection in the rabbit model, and they indicate the potential of teixobactin as a therapeutic for the disease.
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Affiliation(s)
- William S. Lawrence
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; (J.E.P.); (D.W.C.B.); (J.E.C.); (J.W.P.)
- Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA;
- Correspondence: ; Tel.: +1-409-266-6919
| | - Jennifer E. Peel
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; (J.E.P.); (D.W.C.B.); (J.E.C.); (J.W.P.)
| | - Satheesh K. Sivasubramani
- Directorate of Environmental Health Effects Laboratory, Naval Medical Research Unit, Dayton, OH 45433, USA;
| | - Wallace B. Baze
- Department of Comparative Medicine, University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA;
| | - Elbert B. Whorton
- Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA;
| | - David W. C. Beasley
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; (J.E.P.); (D.W.C.B.); (J.E.C.); (J.W.P.)
- Institutional Office of Regulated Nonclinical Studies, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Jason E. Comer
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; (J.E.P.); (D.W.C.B.); (J.E.C.); (J.W.P.)
- Institutional Office of Regulated Nonclinical Studies, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Dallas E. Hughes
- NovoBiotic Pharmaceuticals, LLC, Cambridge, MA 02138, USA; (D.E.H.); (L.L.L.)
| | - Losee L. Ling
- NovoBiotic Pharmaceuticals, LLC, Cambridge, MA 02138, USA; (D.E.H.); (L.L.L.)
| | - Johnny W. Peterson
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; (J.E.P.); (D.W.C.B.); (J.E.C.); (J.W.P.)
- Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA;
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Tran SL, Cormontagne D, Vidic J, André-Leroux G, Ramarao N. Structural Modeling of Cell Wall Peptidase CwpFM (EntFM) Reveals Distinct Intrinsically Disordered Extensions Specific to Pathogenic Bacillus cereus Strains. Toxins (Basel) 2020; 12:toxins12090593. [PMID: 32937845 PMCID: PMC7551459 DOI: 10.3390/toxins12090593] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/04/2020] [Accepted: 09/09/2020] [Indexed: 12/21/2022] Open
Abstract
The emergence of B. cereus as an opportunistic food-borne pathogen has intensified the need to distinguish strains of public health concern. The heterogeneity of the diseases associated with B. cereus infections emphasizes the versatility of these bacteria strains to colonize their host. Nevertheless, the molecular basis of these differences remains unclear. Several toxins are involved in virulence, particularly in gastrointestinal disorders, but there are currently no biological markers able to differentiate pathogenic from harmless strains. We have previously shown that CwpFM is a cell wall peptidase involved in B. cereus virulence. Here, we report a sequence/structure/function characterization of 39 CwpFM sequences, chosen from a collection of B. cereus with diverse virulence phenotypes, from harmless to highly pathogenic strains. CwpFM is homology-modeled in silico as an exported papain-like endopeptidase, with an N-terminal end composed of three successive bacterial Src Homology 3 domains (SH3b1–3) likely to control protein–protein interactions in signaling pathways, and a C-terminal end that contains a catalytic NLPC_P60 domain primed to form a competent active site. We confirmed in vitro that CwpFM is an endopeptidase with a moderate peptidoglycan hydrolase activity. Remarkably, CwpFMs from pathogenic strains harbor a specific stretch of twenty residues intrinsically disordered, inserted between the SH3b3 and the catalytic NLPC_P60 domain. This strongly suggests this linker as a marker of differentiation between B. cereus strains. We believe that our findings improve our understanding of the pathogenicity of B. cereus while advancing both clinical diagnosis and food safety.
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Affiliation(s)
- Seav-Ly Tran
- Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France; (S.-L.T.); (D.C.); (J.V.)
| | - Delphine Cormontagne
- Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France; (S.-L.T.); (D.C.); (J.V.)
| | - Jasmina Vidic
- Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France; (S.-L.T.); (D.C.); (J.V.)
| | - Gwenaëlle André-Leroux
- MaIAGE, INRAE, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
- Correspondence: (G.A.-L.); (N.R.)
| | - Nalini Ramarao
- Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France; (S.-L.T.); (D.C.); (J.V.)
- Correspondence: (G.A.-L.); (N.R.)
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Aminu OR, Lembo T, Zadoks RN, Biek R, Lewis S, Kiwelu I, Mmbaga BT, Mshanga D, Shirima G, Denwood M, Forde TL. Practical and effective diagnosis of animal anthrax in endemic low-resource settings. PLoS Negl Trop Dis 2020; 14:e0008655. [PMID: 32925904 PMCID: PMC7513992 DOI: 10.1371/journal.pntd.0008655] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 09/24/2020] [Accepted: 07/28/2020] [Indexed: 11/19/2022] Open
Abstract
Anthrax threatens human and animal health, and people's livelihoods in many rural communities in Africa and Asia. In these areas, anthrax surveillance is challenged by a lack of tools for on-site detection. Furthermore, cultural practices and infrastructure may affect sample availability and quality. Practical yet accurate diagnostic solutions are greatly needed to quantify anthrax impacts. We validated microscopic and molecular methods for the detection of Bacillus anthracis in field-collected blood smears and identified alternative samples suitable for anthrax confirmation in the absence of blood smears. We investigated livestock mortalities suspected to be caused by anthrax in northern Tanzania. Field-prepared blood smears (n = 152) were tested by microscopy using four staining techniques as well as polymerase chain reaction (PCR) followed by Bayesian latent class analysis. Median sensitivity (91%, CI 95% [84-96%]) and specificity (99%, CI 95% [96-100%]) of microscopy using azure B were comparable to those of the recommended standard, polychrome methylene blue, PMB (92%, CI 95% [84-97%] and 98%, CI 95% [95-100%], respectively), but azure B is more available and convenient. Other commonly-used stains performed poorly. Blood smears could be obtained for <50% of suspected anthrax cases due to local customs and conditions. However, PCR on DNA extracts from skin, which was almost always available, had high sensitivity and specificity (95%, CI 95% [90-98%] and 95%, CI 95% [87-99%], respectively), even after extended storage at ambient temperature. Azure B microscopy represents an accurate diagnostic test for animal anthrax that can be performed with basic laboratory infrastructure and in the field. When blood smears are unavailable, PCR using skin tissues provides a valuable alternative for confirmation. Our findings lead to a practical diagnostic approach for anthrax in low-resource settings that can support surveillance and control efforts for anthrax-endemic countries globally.
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Affiliation(s)
- Olubunmi R. Aminu
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Tiziana Lembo
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Ruth N. Zadoks
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Roman Biek
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Suzanna Lewis
- Public Health England, Porton Down, Salisbury, United Kingdom
| | - Ireen Kiwelu
- Kilimanjaro Clinical Research Institute, Kilimanjaro Christian Medical Centre, Moshi, Tanzania
- Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Blandina T. Mmbaga
- Kilimanjaro Clinical Research Institute, Kilimanjaro Christian Medical Centre, Moshi, Tanzania
- Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | | | - Gabriel Shirima
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Matt Denwood
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Taya L. Forde
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
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Alameh S, Bartolo G, O’Brien S, Henderson EA, Gonzalez LO, Hartmann S, Klimko CP, Shoe JL, Cote CK, Grill LK, Levitin A, Martchenko Shilman M. Anthrax toxin component, Protective Antigen, protects insects from bacterial infections. PLoS Pathog 2020; 16:e1008836. [PMID: 32866212 PMCID: PMC7458312 DOI: 10.1371/journal.ppat.1008836] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 07/24/2020] [Indexed: 01/23/2023] Open
Abstract
Anthrax is a major zoonotic disease of wildlife, and in places like West Africa, it can be caused by Bacillus anthracis in arid nonsylvatic savannahs, and by B. cereus biovar anthracis (Bcbva) in sylvatic rainforests. Bcbva-caused anthrax has been implicated in as much as 38% of mortality in rainforest ecosystems, where insects can enhance the transmission of anthrax-causing bacteria. While anthrax is well-characterized in mammals, its transmission by insects points to an unidentified anthrax-resistance mechanism in its vectors. In mammals, a secreted anthrax toxin component, 83 kDa Protective Antigen (PA83), binds to cell-surface receptors and is cleaved by furin into an evolutionary-conserved PA20 and a pore-forming PA63 subunits. We show that PA20 increases the resistance of Drosophila flies and Culex mosquitoes to bacterial challenges, without directly affecting the bacterial growth. We further show that the PA83 loop known to be cleaved by furin to release PA20 from PA63 is, in part, responsible for the PA20-mediated protection. We found that PA20 binds directly to the Toll activating peptidoglycan-recognition protein-SA (PGRP-SA) and that the Toll/NF-κB pathway is necessary for the PA20-mediated protection of infected flies. This effect of PA20 on innate immunity may also exist in mammals: we show that PA20 binds to human PGRP-SA ortholog. Moreover, the constitutive activity of Imd/NF-κB pathway in MAPKK Dsor1 mutant flies is sufficient to confer the protection from bacterial infections in a manner that is independent of PA20 treatment. Lastly, Clostridium septicum alpha toxin protects flies from anthrax-causing bacteria, showing that other pathogens may help insects resist anthrax. The mechanism of anthrax resistance in insects has direct implications on insect-mediated anthrax transmission for wildlife management, and with potential for applications, such as reducing the sensitivity of pollinating insects to bacterial pathogens.
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Affiliation(s)
- Saleem Alameh
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Gloria Bartolo
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Summer O’Brien
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Elizabeth A. Henderson
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Leandra O. Gonzalez
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Stella Hartmann
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Christopher P. Klimko
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Jennifer L. Shoe
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Christopher K. Cote
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, United States of America
| | - Laurence K. Grill
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
| | - Anastasia Levitin
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
- * E-mail: (AL); (MMS)
| | - Mikhail Martchenko Shilman
- Henry E. Riggs School of Applied Life Sciences, Keck Graduate Institute, Claremont, California, United States of America
- * E-mail: (AL); (MMS)
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Oh Y, Kim JA, Kim CH, Choi SK, Pan JG. Bacillus subtilis spore vaccines displaying protective antigen induce functional antibodies and protective potency. BMC Vet Res 2020; 16:259. [PMID: 32723323 PMCID: PMC7385935 DOI: 10.1186/s12917-020-02468-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 07/10/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacillus anthracis is the causative agent of anthrax, a disease of both humans and various animal species, and can be used as a bioterror agent. Effective vaccines are available, but those could benefit from improvements, including increasing the immunity duration, reducing the shot frequency and adverse reactions. In addition, more sophisticated antigen delivery and potentiation systems are urgently required. The protective antigen (PA), one of three major virulence factors associated with anthrax was displayed on the surface of Bacillus subtilis spores, which is a vaccine production host and delivery vector with several advantages such as a low production cost, straightforward administration as it is safe for human consumption and the particulate adjuvanticity. Mice were immunized orally (PO), intranasally (IN), sublingually (SL) or intraperitoneally (IP) with the PA displaying probiotic spore vaccine. Clinical observation, serological analysis and challenge experiment were conducted to investigate the safety and efficacy of the vaccine. RESULTS A/J mice immunized with the PA spore vaccine via PO, IN, SL, and IP were observed to have increased levels of active antibody titer, isotype profiles and toxin neutralizing antibody in sera, and IgA in saliva. The immunized mice were demonstrated to raise protective immunity against the challenge with lethal B. anthracis spores. CONCLUSIONS In this study, we developed a B. subtilis spore vaccine that displays the PA on its surface and showed that the PA-displaying spore vaccine was able to confer active immunity to a murine model based on the results of antibody isotype titration, mucosal antibody identification, and a lethal challenge experiment.
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Affiliation(s)
- Yeonsu Oh
- Department of Veterinary Pathology, College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon, 24341 Republic of Korea
| | - Jung Ae Kim
- Infectious Disease Research Center (Superbacteria Group), Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Chang-Hwan Kim
- The 4th R&D Institute, Agency for Defense Development (ADD), Yuseong, Daejeon, 34186 Republic of Korea
| | - Soo-Keun Choi
- Infectious Disease Research Center (Superbacteria Group), Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Jae-Gu Pan
- Infectious Disease Research Center (Superbacteria Group), Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
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Hu Z, Liu H, Zhang H, Zhang X, Zhou M, Lou L, Zheng P, Xi C, Hu B. Temporal discrepancy of airborne total bacteria and pathogenic bacteria between day and night. ENVIRONMENTAL RESEARCH 2020; 186:109540. [PMID: 32339956 DOI: 10.1016/j.envres.2020.109540] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/14/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
As the most abundant microbes in the atmosphere, airborne bacteria are closely involved in affecting human health, regional climate and ecological balance. The mobility of airborne microorganisms makes it necessary to study the community dynamic in short cycle. Nevertheless, it remains obscure how the airborne bacteria especially the pathogenic bacteria vary on the small time scale of day and night. To investigate the nycterohemeral discrepancy of airborne total bacteria and pathogenic bacteria, PM2.5 samples were collected in Hangzhou between day and night. Microbial taxonomic information was obtained through 16S rRNA gene sequencing and "human pathogens database" screening. Further analyses based on Multiple Regression Matrices (MRM) approach and Concentration Weighted Trajectory (CWT) model were conducted to elucidate the effect of local environmental factors and long-range transport. The community composition of total bacteria tended to be similar in the daytime while pathogenic bacteria turned out to be homogeneous in the nighttime. To be vigilant, the diversity of airborne pathogenic bacteria echoed the frequency of anthropogenic activities with the pathogen inhalation rate roughly at 428 copies/h and 235 copies/h respectively in daytime and nighttime. The nycterohemeral discrepancy of total bacteria was principally driven by the filtering of environmental factors, i.e., CO and NO2, indicating that anthropogenic activities brought about the homogeneity. Airborne pathogenic bacteria coupled with the strong resistances of environmental filtering stood out from their non-pathogenic counterpart, which enabled the long-range transport. Indeed, the nycterohemeral discrepancy of pathogenic bacteria was shaped by the transport of air masses. This research filled the gaps in temporal variance of airborne microorganisms on the small time scale of day and night, providing crucial foundation for precisely predicting ecological and health effects of bioaerosols.
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Affiliation(s)
- Zhichao Hu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Huan Liu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Hao Zhang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Xu Zhang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Meng Zhou
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Liping Lou
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Ping Zheng
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Chuanwu Xi
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA.
| | - Baolan Hu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
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Thouret JM, Rogeaux O, Beaudouin E, Levast M, Ramisse V, Biot FV, Valade E, Thibault F, Gorgé O, Tournier JN. Case Report of an Injectional Anthrax in France, 2012. Microorganisms 2020; 8:microorganisms8070985. [PMID: 32630109 PMCID: PMC7409126 DOI: 10.3390/microorganisms8070985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/26/2020] [Accepted: 06/26/2020] [Indexed: 11/26/2022] Open
Abstract
(1) Background: Bacillus anthracis is a spore-forming, Gram-positive bacterium causing anthrax, a zoonosis affecting mainly livestock. When occasionally infecting humans, B. anthracis provokes three different clinical forms: cutaneous, digestive and inhalational anthrax. More recently, an injectional anthrax form has been described in intravenous drug users. (2) Case presentation: We report here the clinical and microbiological features, as well as the strain phylogenetic analysis, of the only injectional anthrax case observed in France so far. A 27-year-old patient presented a massive dermohypodermatitis with an extensive edema of the right arm, and the development of drug-resistant shocks. After three weeks in an intensive care unit, the patient recovered, but the microbiological identification of B. anthracis was achieved after a long delay. (3) Conclusions: Anthrax diagnostic may be difficult clinically and microbiologically. The phylogenetic analysis of the Bacillus anthracis strain PF1 confirmed its relatedness to the injectional anthrax European outbreak group-II.
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Affiliation(s)
- Jean-Marc Thouret
- Centre Hospitalier Centre Hospitalier Métropole Savoie, rue Lucien Bizet, 73000 Chambéry, France; (J.-M.T.); (O.R.); (E.B.); (M.L.)
| | - Olivier Rogeaux
- Centre Hospitalier Centre Hospitalier Métropole Savoie, rue Lucien Bizet, 73000 Chambéry, France; (J.-M.T.); (O.R.); (E.B.); (M.L.)
| | - Emmanuel Beaudouin
- Centre Hospitalier Centre Hospitalier Métropole Savoie, rue Lucien Bizet, 73000 Chambéry, France; (J.-M.T.); (O.R.); (E.B.); (M.L.)
| | - Marion Levast
- Centre Hospitalier Centre Hospitalier Métropole Savoie, rue Lucien Bizet, 73000 Chambéry, France; (J.-M.T.); (O.R.); (E.B.); (M.L.)
| | - Vincent Ramisse
- DGA Maîtrise NRBC, 5 rue Lavoisier, 91710 Vert le Petit, France;
| | - Fabrice V. Biot
- CNR-LE Charbon (National Reference Laboratory for Anthrax), Institut de Recherche Biomédicale des Armées, 1 Place Général Valérie André, 91220 Brétigny sur Orge, France; (F.V.B.); (E.V.); (F.T.); (O.G.)
- Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 1 Place Général Valérie André, 91220 Brétigny sur Orge, France
| | - Eric Valade
- CNR-LE Charbon (National Reference Laboratory for Anthrax), Institut de Recherche Biomédicale des Armées, 1 Place Général Valérie André, 91220 Brétigny sur Orge, France; (F.V.B.); (E.V.); (F.T.); (O.G.)
- Direction Centrale du Service de Santé des Armées, 60 Boulevard du Général Martial Valin, 75015 Paris, France
- Ecole du Val-de-Grâce, 1 Place Alphonse Laveran, 75 005 Paris, France
| | - François Thibault
- CNR-LE Charbon (National Reference Laboratory for Anthrax), Institut de Recherche Biomédicale des Armées, 1 Place Général Valérie André, 91220 Brétigny sur Orge, France; (F.V.B.); (E.V.); (F.T.); (O.G.)
| | - Olivier Gorgé
- CNR-LE Charbon (National Reference Laboratory for Anthrax), Institut de Recherche Biomédicale des Armées, 1 Place Général Valérie André, 91220 Brétigny sur Orge, France; (F.V.B.); (E.V.); (F.T.); (O.G.)
- Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 1 Place Général Valérie André, 91220 Brétigny sur Orge, France
| | - Jean-Nicolas Tournier
- CNR-LE Charbon (National Reference Laboratory for Anthrax), Institut de Recherche Biomédicale des Armées, 1 Place Général Valérie André, 91220 Brétigny sur Orge, France; (F.V.B.); (E.V.); (F.T.); (O.G.)
- Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 1 Place Général Valérie André, 91220 Brétigny sur Orge, France
- Ecole du Val-de-Grâce, 1 Place Alphonse Laveran, 75 005 Paris, France
- Correspondence: ; Tel.: +33-178-65-1065
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FINKE ERNSTJÜRGEN, BEYER WOLFGANG, LODERSTÄDT ULRIKE, FRICKMANN HAGEN. Review: The risk of contracting anthrax from spore-contaminated soil - A military medical perspective. Eur J Microbiol Immunol (Bp) 2020; 10:29-63. [PMID: 32590343 PMCID: PMC7391381 DOI: 10.1556/1886.2020.00008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 04/10/2020] [Indexed: 12/31/2022] Open
Abstract
Anthrax is an infectious disease of relevance for military forces. Although spores of Bacillus anthracis obiquitously occur in soil, reports on soil-borne transmission to humans are scarce. In this narrative review, the potential of soil-borne transmission of anthrax to humans is discussed based on pathogen-specific characteristics and reports on anthrax in the course of several centuries of warfare. In theory, anthrax foci can pose a potential risk of infection to animals and humans if sufficient amounts of virulent spores are present in the soil even after an extended period of time. In praxis, however, transmissions are usually due to contacts with animal products and reported events of soil-based transmissions are scarce. In the history of warfare, even in the trenches of World War I, reported anthrax cases due to soil-contaminated wounds are virtually absent. Both the perspectives and the experience of the Western hemisphere and of former Soviet Republics are presented. Based on the accessible data as provided in the review, the transmission risk of anthrax by infections of wounds due to spore-contaminated soil is considered as very low under the most circumstance. Active historic anthrax foci may, however, still pose a risk to the health of deployed soldiers.
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Affiliation(s)
| | - WOLFGANG BEYER
- Department of Infectiology and Animal Hygiene, University of Hohenheim, Institute of Animal Science, Stuttgart, Germany
| | - ULRIKE LODERSTÄDT
- Diagnostic Department, Bernhard-Nocht-Institute for Tropical Medicine Hamburg, Hamburg, Germany
| | - HAGEN FRICKMANN
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Hamburg, Germany
- Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
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Chen H, Li F, Wang L, Jin Y, Chi CH, Kurgan L, Song J, Shen J. Systematic evaluation of machine learning methods for identifying human-pathogen protein-protein interactions. Brief Bioinform 2020; 22:5847611. [PMID: 32459334 DOI: 10.1093/bib/bbaa068] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 12/11/2022] Open
Abstract
In recent years, high-throughput experimental techniques have significantly enhanced the accuracy and coverage of protein-protein interaction identification, including human-pathogen protein-protein interactions (HP-PPIs). Despite this progress, experimental methods are, in general, expensive in terms of both time and labour costs, especially considering that there are enormous amounts of potential protein-interacting partners. Developing computational methods to predict interactions between human and bacteria pathogen has thus become critical and meaningful, in both facilitating the detection of interactions and mining incomplete interaction maps. In this paper, we present a systematic evaluation of machine learning-based computational methods for human-bacterium protein-protein interactions (HB-PPIs). We first reviewed a vast number of publicly available databases of HP-PPIs and then critically evaluate the availability of these databases. Benefitting from its well-structured nature, we subsequently preprocess the data and identified six bacterium pathogens that could be used to study bacterium subjects in which a human was the host. Additionally, we thoroughly reviewed the literature on 'host-pathogen interactions' whereby existing models were summarized that we used to jointly study the impact of different feature representation algorithms and evaluate the performance of existing machine learning computational models. Owing to the abundance of sequence information and the limited scale of other protein-related information, we adopted the primary protocol from the literature and dedicated our analysis to a comprehensive assessment of sequence information and machine learning models. A systematic evaluation of machine learning models and a wide range of feature representation algorithms based on sequence information are presented as a comparison survey towards the prediction performance evaluation of HB-PPIs.
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Drewnowska JM, Stefanska N, Czerniecka M, Zambrowski G, Swiecicka I. Potential Enterotoxicity of Phylogenetically Diverse Bacillus cereus Sensu Lato Soil Isolates from Different Geographical Locations. Appl Environ Microbiol 2020; 86:e03032-19. [PMID: 32220844 PMCID: PMC7237779 DOI: 10.1128/aem.03032-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 03/20/2020] [Indexed: 02/06/2023] Open
Abstract
Bacillus cereus sensu lato comprises Gram-positive spore-forming bacteria producing toxins associated with foodborne diseases. Three pore-forming enterotoxins, nonhemolytic enterotoxin (Nhe), hemolysin BL (Hbl), and cytotoxin K (CytK), are considered the primary factors in B. cereus sensu lato diarrhea. The aim of this study was to determine the potential risk of enterotoxicity among soil B. cereus sensu lato isolates representing diverse phylogroups and originated from different geographic locations with various climates (Burkina Faso, Kenya, Argentina, Kazakhstan, and Poland). While nheA- and hblA-positive isolates were present among all B. cereus sensu lato populations and distributed across all phylogenetic groups, cytK-2-positive strains predominated in geographic regions with an arid hot climate (Africa) and clustered together on a phylogenetic tree mainly within mesophilic groups III and IV. The highest in vitro cytotoxicity to Caco-2 and HeLa cells was demonstrated by the strains clustered within phylogroups II and IV. Overall, our results suggest that B. cereus sensu lato pathogenicity is a comprehensive process conditioned by many intracellular factors and diverse environmental conditions.IMPORTANCE This research offers a new route for a wider understanding of the dependency between pathogenicity and phylogeny of a natural bacterial population, specifically within Bacillus cereus sensu lato, that is widely distributed around the world and easily transferred into food products. Our study indicates differences in the phylogenetic and geographical distributions of potential enterotoxigenic B. cereus sensu lato strains. Hence, these bacilli possess a risk for human health, and rapid testing methods for their identification are greatly needed. In particular, the detection of the CytK enterotoxin should be a supporting strategy for the identification of pathogenic B. cereus sensu lato.
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Affiliation(s)
| | - Natalia Stefanska
- Department of Microbiology, Faculty of Biology, University of Bialystok, Bialystok, Poland
| | - Magdalena Czerniecka
- Department of Cytobiochemistry, Faculty of Biology, University of Bialystok, Bialystok, Poland
- Laboratory of Tissue Culture, Faculty of Biology, University of Bialystok, Bialystok, Poland
| | - Grzegorz Zambrowski
- Laboratory of Applied Microbiology, University of Bialystok, Bialystok, Poland
| | - Izabela Swiecicka
- Department of Microbiology, Faculty of Biology, University of Bialystok, Bialystok, Poland
- Laboratory of Applied Microbiology, University of Bialystok, Bialystok, Poland
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Toxin-neutralizing antibodies elicited by naturally acquired cutaneous anthrax are elevated following severe disease and appear to target conformational epitopes. PLoS One 2020; 15:e0230782. [PMID: 32294093 PMCID: PMC7159215 DOI: 10.1371/journal.pone.0230782] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 03/09/2020] [Indexed: 01/03/2023] Open
Abstract
Understanding immune responses to native antigens in response to natural infections can lead to improved approaches to vaccination. This study sought to characterize the humoral immune response to anthrax toxin components, capsule and spore antigens in individuals (n = 46) from the Kayseri and Malatya regions of Turkey who had recovered from mild or severe forms of cutaneous anthrax infection, compared to regional healthy controls (n = 20). IgG antibodies to each toxin component, the poly-γ-D-glutamic acid capsule, the Bacillus collagen-like protein of anthracis (BclA) spore antigen, and the spore carbohydrate anthrose, were detected in the cases, with anthrax toxin neutralization and responses to Protective Antigen (PA) and Lethal Factor (LF) being higher following severe forms of the disease. Significant correlative relationships among responses to PA, LF, Edema Factor (EF) and capsule were observed among the cases. Though some regional control sera exhibited binding to a subset of the tested antigens, these samples did not neutralize anthrax toxins and lacked correlative relationships among antigen binding specificities observed in the cases. Comparison of serum binding to overlapping decapeptides covering the entire length of PA, LF and EF proteins in 26 cases compared to 8 regional controls revealed that anthrax toxin-neutralizing antibody responses elicited following natural cutaneous anthrax infection are directed to conformational epitopes. These studies support the concept of vaccination approaches that preserve conformational epitopes.
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Brownlie T, Bishop T, Parry M, Salmon SE, Hunnam JC. Predicting the periodic risk of anthrax in livestock in Victoria, Australia, using meteorological data. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2020; 64:601-610. [PMID: 31942644 DOI: 10.1007/s00484-019-01849-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 09/30/2019] [Accepted: 12/17/2019] [Indexed: 06/10/2023]
Abstract
Cases of anthrax in livestock are infrequently and irregularly reported in the state of Victoria, Australia; however, their impact on individual livestock, farming communities and the government agencies tasked with containing these outbreaks is high. This infrequency has been anecdotally associated with differences in annual and local weather patterns. In this study, we used historical anthrax cases and meteorological data from weather stations throughout Victoria to train a generalized linear mixed effects model to predict the daily odds of a case of anthrax occurring in each shire in the coming 30 days. Meteorological variables were transformed to deviations from the mean values for temperature or cumulative values for rainfall in the shire across all years. Shire was incorporated as a random effect to account for meteorological variation between shires. The model incorporated a post hoc weighting for the frequency of historic cases within each shire and the spatial contribution of each shire to the recently redefined Australian Anthrax Belt. Our model reveals that anthrax cases were associated with drier summer conditions (OR 0.96 (95% CI 0.95-0.97) and OR 0.98 (95% CI 0.97-0.99) for every mm increase in rainfall during September and December, respectively) and cooler than average spring (OR 0.20 (95% CI 0.11-0.52) for every °C increase in minimum daily temperature during November and warmer than average summer temperatures (OR 1.45 (95% CI 1.29-1.61) for every °C increase in maximum daily temperature during January. Cases were also preceded by a 40-day period of cooler, drier temperatures (OR 0.5 (95% CI 0.27-0.74) for every °C increase in maximum daily temperature and OR 0.96 (95% CI 0.95-0.97) for every mm increase in rainfall followed by a warmer than average minimum (or nightly) temperature 10 days immediately before the case (OR 1.46 (95% CI 1.35-1.58) for every °C increase in maximum daily temperature). These coefficients of this training model were then applied daily to meteorological data for each shire, and output of these models was presented as a choropleth and timeline plot in a Shiny web application. The application builds on previous spatial modelling and provides Victorian agencies with a tool to engage at-risk farmers and guide discussions towards anthrax control. This application can contribute to the wider rejuvenation of anthrax knowledge and control in Victoria and corroborates the anecdote that increased odds of disease can be linked to meteorological events.
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Affiliation(s)
- T Brownlie
- Working Formula Ltd, Dunedin, New Zealand.
| | - T Bishop
- Working Formula Ltd, Dunedin, New Zealand
| | - M Parry
- Department of Mathematics and Statistics, University of Otago, Dunedin, New Zealand
| | - S E Salmon
- Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources, Attwood, Victoria, Australia
| | - J C Hunnam
- Agriculture Victoria, Department of Economic Development, Jobs, Transport and Resources, Attwood, Victoria, Australia
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Laut CL, Perry WJ, Metzger AL, Weiss A, Stauff DL, Walker S, Caprioli RM, Skaar EP. Bacillus anthracis Responds to Targocil-Induced Envelope Damage through EdsRS Activation of Cardiolipin Synthesis. mBio 2020; 11:e03375-19. [PMID: 32234818 PMCID: PMC7157781 DOI: 10.1128/mbio.03375-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 02/27/2020] [Indexed: 01/08/2023] Open
Abstract
Bacillus anthracis is a spore-forming bacterium that causes devastating infections and has been used as a bioterror agent. This pathogen can survive hostile environments through the signaling activity of two-component systems, which couple environmental sensing with transcriptional activation to initiate a coordinated response to stress. In this work, we describe the identification of a two-component system, EdsRS, which mediates the B. anthracis response to the antimicrobial compound targocil. Targocil is a cell envelope-targeting compound that is toxic to B. anthracis at high concentrations. Exposure to targocil causes damage to the cellular barrier and activates EdsRS to induce expression of a previously uncharacterized cardiolipin synthase, which we have named ClsT. Both EdsRS and ClsT are required for protection against targocil-dependent damage. Induction of clsT by EdsRS during targocil treatment results in an increase in cardiolipin levels, which protects B. anthracis from envelope damage. Together, these results reveal that a two-component system signaling response to an envelope-targeting antimicrobial induces production of a phospholipid associated with stabilization of the membrane. Cardiolipin is then used to repair envelope damage and promote B. anthracis viability.IMPORTANCE Compromising the integrity of the bacterial cell barrier is a common action of antimicrobials. Targocil is an antimicrobial that is active against the bacterial envelope. We hypothesized that Bacillus anthracis, a potential weapon of bioterror, senses and responds to targocil to alleviate targocil-dependent cell damage. Here, we show that targocil treatment increases the permeability of the cellular envelope and is particularly toxic to B. anthracis spores during outgrowth. In vegetative cells, two-component system signaling through EdsRS is activated by targocil. This results in an increase in the production of cardiolipin via a cardiolipin synthase, ClsT, which restores the loss of barrier function, thereby reducing the effectiveness of targocil. By elucidating the B. anthracis response to targocil, we have uncovered an intrinsic mechanism that this pathogen employs to resist toxicity and have revealed therapeutic targets that are important for bacterial defense against structural damage.
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Affiliation(s)
- Clare L Laut
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - William J Perry
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee, USA
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Andy Weiss
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Devin L Stauff
- Department of Biology, Grove City College, Grove City, Pennsylvania, USA
| | - Suzanne Walker
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Richard M Caprioli
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee, USA
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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Comparative Analysis of Blood and Marrow Cellular Structure of White Mice Infected With Bacillus Anthracis Different Genotypes. ACTA BIOMEDICA SCIENTIFICA 2020. [DOI: 10.29413/abs.2020-5.1.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background. Detection of the pathogenicity factors is one of the actual directions in studying of the anthrax causative agent. First of all, it includes the presence of tripartite toxin, capsule and the related structural and regulatory genes. Their presence or absence is defined by structural changes in cellular structure of blood and immunocomplex organs of a macroorganism.Objective: To conduct a comparative analysis of subpopulational structure of marrow and peripheral blood cells at anthrax infection in experimental animals and to trace dynamics of the infectious process caused by Bacillus anthracis of different genotypes.Methods. Comparative examination of subpopulational structure of red marrow and peripheral blood cells of white mice in dynamics of the infectious process caused by B. anthracis of different genotypes was conducted. Also, neutrophil maturing index and leucoerythrocytic correlation were calculated in red marrow. Degree of manifestation of neutrophil pathological granularity was revealed in peripheral blood smears stained by the Freifeld’s method. Statistical processing of the received data was conducted using the computer program “Statistics”, version 6 (Novosibirsk). Authentic results were considered if the error probability was less than 0.05 (р < 0.05) in relation to the control.Results. It is revealed that alterations in white mice infected by B. anthracis strains with the same set of plasmids are significantly various.Conclusion. The resulted data permit to assume that the distinction of pathological alterations in peripheral blood and red marrow is probably connected with the other factors of the pathogen invasiveness like enzymatic activity, ability to adhesion and many others.
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Kumar M, Puranik N, Varshney A, Tripathi N, Pal V, Goel AK. BA3338, a surface layer homology domain possessing protein augments immune response and protection efficacy of protective antigen against Bacillus anthracis in mouse model. J Appl Microbiol 2020; 129:443-452. [PMID: 32118336 DOI: 10.1111/jam.14624] [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: 10/16/2019] [Revised: 02/20/2020] [Accepted: 02/26/2020] [Indexed: 02/07/2023]
Abstract
AIM Category A classified Bacillus anthracis is highly fatal pathogen that causes anthrax and creates challenges for global security and public health. In this study, development of a safe and ideal next-generation subunit anthrax vaccine has been evaluated in mouse model. METHOD AND RESULTS Protective antigen (PA) and BA3338, a surface layer homology (SLH) domain possessing protein were cloned, expressed in heterologous system and purified by IMAC. Recombinant PA and BA3338 with alum were administered in mouse alone or in combination. The humoral and cell-mediated immune response was measured by ELISA and vaccinated animals were challenged with B. anthracis spores via intraperitoneal route. The circulating IgG antibody titre of anti-PA and anti-BA3338 was found significantly high in the first and second booster sera. A significant enhanced level of IL-4, IFN-γ and IL-12 was observed in antigens stimulated supernatant of splenocytes of PA + BA3338 vaccinated animals. A combination of PA and BA3338 provided 80% protection against 20 LD50 lethal dose of B. anthracis spores. CONCLUSION Both antigens induced admirable humoral and cellular immune response as well as protective efficacy against B. anthracis spores. SIGNIFICANCE AND IMPACT OF THE STUDY This study has been evaluated for the first time using BA3338 as a vaccine candidate alone or in combination with well-known anthrax vaccine candidate PA. The findings of this study demonstrated that BA3338 could be a co-vaccine candidate for development of dual subunit vaccine against anthrax.
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Affiliation(s)
- M Kumar
- Bioprocess Technology Division, Defence Research and Development Establishment, Gwalior, India
| | - N Puranik
- Bioprocess Technology Division, Defence Research and Development Establishment, Gwalior, India
| | - A Varshney
- Bioprocess Technology Division, Defence Research and Development Establishment, Gwalior, India
| | - N Tripathi
- Bioprocess Technology Division, Defence Research and Development Establishment, Gwalior, India
| | - V Pal
- Bioprocess Technology Division, Defence Research and Development Establishment, Gwalior, India
| | - A K Goel
- Bioprocess Technology Division, Defence Research and Development Establishment, Gwalior, India
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Gogoi H, Mani R, Aggarwal S, Malik A, Munde M, Bhatnagar R. Crystalline and Amorphous Preparation of Aluminum Hydroxide Nanoparticles Enhances Protective Antigen Domain 4 Specific Immunogenicity and Provides Protection Against Anthrax. Int J Nanomedicine 2020; 15:239-252. [PMID: 32021177 PMCID: PMC6970252 DOI: 10.2147/ijn.s219647] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 08/28/2019] [Indexed: 12/19/2022] Open
Abstract
Introduction Aluminum salts, although they have been used as adjuvants in many vaccine formulations since 1926, exclusively induce a Th2-biased immune response, thereby limiting their use against intracellular pathogens like Mycobacterium tuberculosis. Methods and Results Herein, we synthesized amorphous and crystalline forms of aluminum hydroxide nanoparticles (AH nps) of 150–200 nm size range. Using Bacillus anthracis protective antigen domain 4 (D4) as a model antigen, we demonstrated that both amorphous and crystalline forms of AH nps displayed enhanced antigen D4 uptake by THP1 cells as compared to commercial adjuvant aluminum hydroxide gel (AH gel). In a mouse model, both amorphous and crystalline AH nps triggered an enhanced D4-specific Th2- and Th1-type immune response and conferred superior protection against anthrax spore challenge as compared to AH gel. Physicochemical characterization of crystalline and amorphous AH nps revealed stronger antigen D4 binding and release than AH gel. Conclusion These results demonstrate that size and crystallinity of AH nps play important roles in mediating enhanced antigen presenting cells (APCs) activation and potentiating a strong antigen-specific immune response, and are critical parameters for the rational design of alum-based Th1-type adjuvant to induce a more balanced antigen-specific immune response.
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Affiliation(s)
- Himanshu Gogoi
- Laboratory of Genetic Engineering and Molecular Biology, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Rajesh Mani
- Laboratory of Genetic Engineering and Molecular Biology, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Soumya Aggarwal
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Anshu Malik
- Laboratory of Genetic Engineering and Molecular Biology, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Manoj Munde
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Rakesh Bhatnagar
- Laboratory of Genetic Engineering and Molecular Biology, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India.,Banaras Hindu University, Varanasi, Uttar Pradesh, India
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Liu X, Chen D, Wang C, Tian N, Li Z, Zhang Y, Ding ZJ. A turn-on luminescence probe for highly selective detection of an anthrax biomarker. LUMINESCENCE 2020; 35:601-607. [PMID: 31916365 DOI: 10.1002/bio.3764] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 10/21/2019] [Accepted: 12/11/2019] [Indexed: 01/14/2023]
Abstract
Highly selective detection of Bacillus anthrax spores has attracted worldwide attention because Bacillus anthrax spores not only are harmful to the health of human beings and animals, but also can be used as biological warfare agents. Here, we report a simple platform by mixing EuCl3 ·6H2 O and sodium polyacrylate in aqueous solution and further investigate its luminescence response towards Bacillus anthrax biomarker dipicolinic acid (DPA) as a turn-on luminescence probe. Importantly, our probe has good sensitivity, lower detection limit, excellent selectivity as well as great anti-interference ability due to the great luminescence enhancement of Eu3+ . Moreover, a test paper is constructed to realize the purpose of portable detection. These results indicate that our probe is an excellent candidate for sensing DPA.
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Affiliation(s)
- Xiao Liu
- National-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources Utilization, Tianjin Key Laboratory of Chemical Process Safety, School of Chemical Engineering and Technology, Hebei University of Technology, Guangrong Dao 8, Hongqiao District, Tianjin, China
| | - Dong Chen
- Beijing Institute of Pharmaceutical Chemistry, Beijing, China
| | - Chenchen Wang
- National-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources Utilization, Tianjin Key Laboratory of Chemical Process Safety, School of Chemical Engineering and Technology, Hebei University of Technology, Guangrong Dao 8, Hongqiao District, Tianjin, China
| | - Nianjuan Tian
- National-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources Utilization, Tianjin Key Laboratory of Chemical Process Safety, School of Chemical Engineering and Technology, Hebei University of Technology, Guangrong Dao 8, Hongqiao District, Tianjin, China
| | - Zhiqiang Li
- National-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources Utilization, Tianjin Key Laboratory of Chemical Process Safety, School of Chemical Engineering and Technology, Hebei University of Technology, Guangrong Dao 8, Hongqiao District, Tianjin, China
| | - Ying Zhang
- National-Local Joint Engineering Laboratory for Energy Conservation in Chemical Process Integration and Resources Utilization, Tianjin Key Laboratory of Chemical Process Safety, School of Chemical Engineering and Technology, Hebei University of Technology, Guangrong Dao 8, Hongqiao District, Tianjin, China
| | - Zhi-Jun Ding
- Beijing Institute of Pharmaceutical Chemistry, Beijing, China
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Magriñá I, Jauset-Rubio M, Ortiz M, Tomaso H, Simonova A, Hocek M, O’Sullivan CK. Duplex Electrochemical DNA Sensor to Detect Bacillus anthracis CAP and PAG DNA Targets Based on the Incorporation of Tailed Primers and Ferrocene-Labeled dATP. ACS OMEGA 2019; 4:21900-21908. [PMID: 31891068 PMCID: PMC6933787 DOI: 10.1021/acsomega.9b02890] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/21/2019] [Indexed: 05/08/2023]
Abstract
We report the duplex amplification of two plasmid DNA markers involved in the virulence of Bacillus anthracis, CAP and PAG, and the direct electrochemical detection of these amplicons. The method consists of the simultaneous amplification of the two targets in a single-pot reaction via polymerase chain reaction (PCR) using tailed primers and ferrocene-labeled dATP. Following amplification, the PCR products hybridize to probes immobilized on electrodes in a microfabricated electrode array chip. The incorporated ferrocene labeled dATP is then detected using square wave voltammetry. We evaluated the effect of electrolyte cations, anions, and concentration to condense, bend, and shrink double-stranded DNA and their effect on the intensity of the ferrocene signal. We obtained detection limits of 0.8 and 3.4 fM for CAP and PAG targets, respectively. We successfully developed a method to detect the presence of both targets in genomic DNA extracted from real samples.
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Affiliation(s)
- Ivan Magriñá
- INTERFIBIO
Consolidated Research Group, Departament d’Enginyeria Química, Universitat Rovira i Virgili, Avinguda Països Catalans
26, 43007 Tarragona, Spain
| | - Miriam Jauset-Rubio
- INTERFIBIO
Consolidated Research Group, Departament d’Enginyeria Química, Universitat Rovira i Virgili, Avinguda Països Catalans
26, 43007 Tarragona, Spain
| | - Mayreli Ortiz
- INTERFIBIO
Consolidated Research Group, Departament d’Enginyeria Química, Universitat Rovira i Virgili, Avinguda Països Catalans
26, 43007 Tarragona, Spain
| | - Herbert Tomaso
- Friedrich-Loeffler-Institut, Naumburger Str. 96a, 07743 Jena, Germany
| | - Anna Simonova
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Flemingovo nám. 2, CZ-16610 Prague, Czech Republic
- Department
of Organic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, CZ-12843 Prague 2, Czech Republic
| | - Michal Hocek
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Flemingovo nám. 2, CZ-16610 Prague, Czech Republic
- Department
of Organic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, CZ-12843 Prague 2, Czech Republic
| | - Ciara K. O’Sullivan
- INTERFIBIO
Consolidated Research Group, Departament d’Enginyeria Química, Universitat Rovira i Virgili, Avinguda Països Catalans
26, 43007 Tarragona, Spain
- Institució
Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys, 23, 08010 Barcelona, Spain
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73
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Exploring the Nature of Cationic Blocker Recognition by the Anthrax Toxin Channel. Biophys J 2019; 117:1751-1763. [PMID: 31587826 DOI: 10.1016/j.bpj.2019.08.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/11/2019] [Accepted: 08/05/2019] [Indexed: 01/20/2023] Open
Abstract
Obstructing conductive pathways of the channel-forming toxins with targeted blockers is a promising drug design approach. Nearly all tested positively charged ligands have been shown to reversibly block the cation-selective channel-forming protective antigen (PA63) component of the binary anthrax toxin. The cationic ligands with more hydrophobic surfaces, particularly those carrying aromatic moieties, inhibited PA63 more effectively. To understand the physical basis of PA63 selectivity for a particular ligand, detailed information is required on how the blocker structural elements (e.g., positively charged and aromatic groups) influence the molecular kinetics of the blocker/channel binding reactions. In this study, we address this problem using the high-resolution single-channel planar lipid bilayer technique. Several structurally distinct cationic blockers, namely per-6-S-(3-amino) propyl-β-cyclodextrin, per-6-S-(3-aminomethyl) benzyl-α-cyclodextrin, per-6-S-(3-aminomethyl) benzyl-β-cyclodextrin, per-6-S-(3-aminomethyl) benzyl-γ-cyclodextrin, methyltriphenylphosphonium ion, and G0 polyamidoamine dendrimer are tested for their ability to inhibit the heptameric and octameric PA63 variants and PA63F427A mutant. The F427 residues form a hydrophobic constriction region inside the channel, known as the "ϕ-clamp." We show that the cationic blockers interact with PA63 through a combination of forces. Analysis of the binding reaction kinetics suggests the involvement of cation-π, Coulomb, and salt-concentration-independent π-π or hydrophobic interactions in the cationic cyclodextrin binding. It is possible that these blockers bind to the ϕ-clamp and are also stabilized by the Coulomb interactions of their terminal amino groups with the water-exposed negatively charged channel residues. In PA63F427A, only the suggested Coulomb component of the cyclodextrin interaction remains. Methyltriphenylphosphonium ion and G0 polyamidoamine dendrimer, despite being positively charged, interact primarily with the ϕ-clamp. We also show that seven- and eightfold symmetric cyclodextrins effectively block the heptameric and octameric forms of PA63 interchangeably, adding flexibility to the earlier formulated blocker/target symmetry match requirement.
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74
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YpeB dimerization may be required to stabilize SleB for effective germination of Bacillus anthracis spores. BMC Microbiol 2019; 19:169. [PMID: 31349814 PMCID: PMC6660665 DOI: 10.1186/s12866-019-1544-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 07/18/2019] [Indexed: 12/16/2022] Open
Abstract
Background Bacillus cells faced with unfavorable environmental conditions undergo an asymmetric division process ultimately leading to the formation of the bacterial spore. In some instances the spore serves as an infectious agent; such is the case with the spore of Bacillus anthracis and the disease anthrax. Spores are resistant to a variety of environment conditions including traditional decontamination techniques due to the formation of specialized cellular structures. One such structure, the spore cortex, is a thick layer of modified peptidoglycan that contributes to spore dormancy through maintenance of the dehydrated state of the spore core. During spore germination, degradation of the cortex is required to facilitate complete hydration of the core and a return to vegetative growth. Degradation of the cortex is accomplished through the action of germination-specific lytic enzymes. One of these enzymes, SleB, has been previously shown to require the presence of the YpeB protein for its stable incorporation and subsequent function in spores of B. anthracis. The focus of the present study is to identify protein interactions of YpeB through in vivo chemical cross-linking and two-hybrid analysis. Results Conserved residues within YpeB PepSY domains were altered to facilitate implementation of a site-specific chemical cross-linker, 4-Azidophenacyl bromide. Analyses of crosslinked-spore extracts suggests that YpeB exists as a dimer or larger multimer within the spore, potentially mediated through interactions of the C-terminal domains. Spores expressing stable truncated forms of YpeB were crosslinked and corresponding truncated dimers were detected. Further characterization of individual YpeB domains using bacterial two-hybrid analysis indicated a possible role for both N-and C-terminal domains in YpeB oligomerization. Conclusions The YpeB protein likely exists as dimer or higher-order multimer in the dormant spore. Both the N- and C-terminal YpeB domains contribute to multimerization. SleB likely also exists as an oligomer, and SleB and YpeB may be found together within a protein complex. Disassembly of this complex during spore germination likely allows SleB to become active in spore cortex degradation. Further study of this protein complex may contribute to the development of methods to inhibit or stimulate germination, allowing more effective spore decontamination. Electronic supplementary material The online version of this article (10.1186/s12866-019-1544-1) contains supplementary material, which is available to authorized users.
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75
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Koné KM, Douamba Z, Halleux MD, Bougoudogo F, Mahillon J. Prevalence and Diversity of the Thermotolerant Bacterium Bacillus cytotoxicus among Dried Food Products. J Food Prot 2019; 82:1210-1216. [PMID: 31233363 DOI: 10.4315/0362-028x.jfp-19-006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
HIGHLIGHTS Bacillus cytotoxicus was found in all tested potato flakes but at loads lower than 102 CFU/g. B. cytotoxicus was observed in other potato-containing products and in millet flour. B. cytotoxicus isolates (n = 57) fell into six RAPD patterns and 11 plasmid profiles. A large proportion of B. cytotoxicus isolates contained small and/or large plasmids.
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Affiliation(s)
- Klèma Marcel Koné
- 1 Laboratory of Food and Environmental Microbiology, Earth and Life Institute, UCLouvain, Croix du Sud 2/L7.05.12 1348, Louvain-la-Neuve, Belgium
| | - Zoénabo Douamba
- 1 Laboratory of Food and Environmental Microbiology, Earth and Life Institute, UCLouvain, Croix du Sud 2/L7.05.12 1348, Louvain-la-Neuve, Belgium
| | - Maëlle de Halleux
- 1 Laboratory of Food and Environmental Microbiology, Earth and Life Institute, UCLouvain, Croix du Sud 2/L7.05.12 1348, Louvain-la-Neuve, Belgium
| | - Flabou Bougoudogo
- 2 Faculty of Pharmacy, Université des Sciences, des Techniques et des Technologies de Bamako, BP:1805, Bamako, Mali
| | - Jacques Mahillon
- 1 Laboratory of Food and Environmental Microbiology, Earth and Life Institute, UCLouvain, Croix du Sud 2/L7.05.12 1348, Louvain-la-Neuve, Belgium
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76
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Toyomane K, Furuta Y, Fujikura D, Higashi H. Upstream sequence-dependent suppression and AtxA-dependent activation of protective antigens in Bacillus anthracis. PeerJ 2019; 7:e6718. [PMID: 30997291 PMCID: PMC6463858 DOI: 10.7717/peerj.6718] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 03/05/2019] [Indexed: 01/07/2023] Open
Abstract
The anthrax toxin is a virulence factor produced by the bacterium Bacillus anthracis. Transcription of anthrax toxin genes is controlled by the transcription factor AtxA. Thus, AtxA is thought to be a key factor for the pathogenicity of B. anthracis. Despite its important role in B. anthracis infection, the molecular mechanism by which AtxA controls expression of anthrax toxin remains unclear. This study aimed to characterize the molecular mechanism of AtxA-mediated regulation of protective antigen (PA), a component of anthrax toxin encoded by the pagA gene. First, the interaction between the upstream region of pagA and AtxA was evaluated in vivo by constructing a transcriptional fusion of the upstream region with an auxotrophic marker. The results showed that (i) the upstream region of pagA suppressed transcription of the downstream gene and (ii) AtxA recovered suppressed transcription. Second, in vitro analysis using a gel mobility shift assay was performed to evaluate binding specificity of the AtxA–DNA interaction. The result showed sequence-independent binding of AtxA to DNA. Taken together, our findings suggest that the expression of PA was suppressed by the upstream region of pagA and that an interaction of AtxA and the upstream region releases the suppression.
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Affiliation(s)
- Kochi Toyomane
- Division of Infection and Immunity, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Yoshikazu Furuta
- Division of Infection and Immunity, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Daisuke Fujikura
- Division of Infection and Immunity, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Hideaki Higashi
- Division of Infection and Immunity, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
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77
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Bauman ZM, Morizio K, Singer M, Hood CR, Feliciano DV, Vercruysse GA. The Heroin Epidemic in America: A Surgeon's Perspective. Surg Infect (Larchmt) 2019; 20:351-358. [PMID: 30900946 DOI: 10.1089/sur.2019.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: The United States is currently experiencing a heroin epidemic. Recent reports have demonstrated a three-fold increase in heroin use among Americans since 2007 with a shift in demographics to more women and white Americans. Furthermore, there has been a correlation between the recent opioid epidemic and an increase in heroin abuse. Much has been written about epidemiology and prevention of heroin abuse, but little has been dedicated to the surgical implications, complications, and resource utilization. Discussion: This article focuses on the surgical problems encountered from heroin abuse and how to manage them in a constant effort to improve morbidity and mortality for these heroin abusers.
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Affiliation(s)
- Zachary M Bauman
- 1 Division of Trauma, Emergency General Surgery, and Critical Care, Department of Surgery, University of Nebraska, Omaha, Nebraska
| | - Kate Morizio
- 2 Department of Pharmacy, University of Arizona, Tucson, Arizona
| | - Matthew Singer
- 3 Division of Acute Care Surgery, Department of Surgery, University of Arizona, Tucson, Arizona
| | - Courtney R Hood
- 3 Division of Acute Care Surgery, Department of Surgery, University of Arizona, Tucson, Arizona
| | - David V Feliciano
- 4 Division of Surgical Critical Care, University of Maryland Medical Center, Baltimore, Maryland
| | - Gary A Vercruysse
- 5 Division of Acute Care Surgery, Department of Surgery, University of Michigan, Ann Arbor, Michigan
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78
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Blackburn JK, Ganz HH, Ponciano JM, Turner WC, Ryan SJ, Kamath P, Cizauskas C, Kausrud K, Holt RD, Stenseth NC, Getz WM. Modeling R₀ for Pathogens with Environmental Transmission: Animal Movements, Pathogen Populations, and Local Infectious Zones. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:E954. [PMID: 30884913 PMCID: PMC6466347 DOI: 10.3390/ijerph16060954] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 03/04/2019] [Accepted: 03/07/2019] [Indexed: 01/24/2023]
Abstract
How a disease is transmitted affects our ability to determine R₀, the average number of new cases caused by an infectious host at the onset of an epidemic. R₀ becomes progressively more difficult to compute as transmission varies from directly transmitted diseases to diseases that are vector-borne to environmentally transmitted diseases. Pathogens responsible for diseases with environmental transmission are typically maintained in environmental reservoirs that exhibit a complex spatial distribution of local infectious zones (LIZs). Understanding host encounters with LIZs and pathogen persistence within LIZs is required for an accurate R₀ and modeling these contacts requires an integrated geospatial and dynamical systems approach. Here we review how interactions between host and pathogen populations and environmental reservoirs are driven by landscape-level variables, and synthesize the quantitative framework needed to formulate outbreak response and disease control.
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Affiliation(s)
- Jason K Blackburn
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, 3141 Turlington Hall, Gainesville, FL 32611, USA.
- Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, Gainesville, FL 32611, USA.
| | - Holly H Ganz
- Davis Genome Center, University of California, 451 Health Sciences Dr., Davis, CA 95616, USA.
| | | | - Wendy C Turner
- Department of Biological Sciences, State University of New York, 1400 Washington Avenue, Albany, NY 12222, USA.
| | - Sadie J Ryan
- Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, Gainesville, FL 32611, USA.
- Quantitative Disease Ecology & Conservation Lab, Department of Geography, University of Florida, 3141 Turlington Hall, Gainesville, FL 32611, USA.
- School of Life Sciences, University of KwaZulu-Natal, Durban 4041, South Africa.
| | - Pauline Kamath
- School of Food and Agriculture, University of Maine, 5763 Rogers Hall, Room 210, Orono, ME 04469, USA.
| | - Carrie Cizauskas
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, 130 Mulford Hall, Berkeley, CA 94720, USA.
| | - Kyrre Kausrud
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0361 Oslo, Norway.
| | - Robert D Holt
- Department of Biology, University of Florida, Gainesville, FL 32611, USA.
| | - Nils Chr Stenseth
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0361 Oslo, Norway.
| | - Wayne M Getz
- School of Food and Agriculture, University of Maine, 5763 Rogers Hall, Room 210, Orono, ME 04469, USA.
- School of Mathematical Sciences, University of KwaZulu-Natal, Durban 4041, South Africa.
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79
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Bacillus anthracis Edema Toxin Inhibits Efferocytosis in Human Macrophages and Alters Efferocytic Receptor Signaling. Int J Mol Sci 2019; 20:ijms20051167. [PMID: 30866434 PMCID: PMC6429438 DOI: 10.3390/ijms20051167] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 02/27/2019] [Accepted: 03/04/2019] [Indexed: 12/21/2022] Open
Abstract
The Bacillus anthracis Edema Toxin (ET), composed of a Protective Antigen (PA) and the Edema Factor (EF), is a cellular adenylate cyclase that alters host responses by elevating cyclic adenosine monophosphate (cAMP) to supraphysiologic levels. However, the role of ET in systemic anthrax is unclear. Efferocytosis is a cAMP-sensitive, anti-inflammatory process of apoptotic cell engulfment, the inhibition of which may promote sepsis in systemic anthrax. Here, we tested the hypothesis that ET inhibits efferocytosis by primary human macrophages and evaluated the mechanisms of altered efferocytic signaling. ET, but not PA or EF alone, inhibited the efferocytosis of early apoptotic neutrophils (PMN) by primary human M2 macrophages (polarized with IL-4, IL-10, and/or dexamethasone) at concentrations relevant to those encountered in systemic infection. ET inhibited Protein S- and MFGE8-dependent efferocytosis initiated by signaling through MerTK and αVβ5 receptors, respectively. ET inhibited Rac1 activation as well as the phosphorylation of Rac1 and key activating sites of calcium calmodulin-dependent kinases CamK1α, CamK4, and vasodilator-stimulated phosphoprotein, that were induced by the exposure of M2(Dex) macrophages to Protein S-opsonized apoptotic PMN. These results show that ET impairs macrophage efferocytosis and alters efferocytic receptor signaling.
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80
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Abstract
Why some parasites evolve and maintain extreme levels of virulence is a question that remains largely unanswered. A body of theory predicts that parasites that form long-lived spores able to persist in the environment evolve higher virulence, known as the sit and wait hypothesis. Such parasites can obliterate their local host population and wait in the environment for further hosts to arrive, reducing some of the costs of high virulence. On the other hand, some models predict the opposite to be true, that virulence and environmental persistence are both costly and traded off, the resource allocation hypothesis. I conducted a meta-analysis on published data on the relationship between environmental persistence and virulence collected to date. I first examined all data available to date and then conducted a smaller analysis focussing on just those studies testing the specific predictions of the sit and wait hypothesis. Empirical work supports both hypotheses; however, the direction of the effect is largely associated with parasite type. In both analyses, viruses tend to show evidence of resource allocation trade-offs, these traits are positively correlated in bacterial and fungal parasites.
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81
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Schnell L, Felix I, Müller B, Sadi M, Bank F, Papatheodorou P, Popoff MR, Aktories K, Waltenberger E, Benz R, Weichbrodt C, Fauler M, Frick M, Barth H. Revisiting an old antibiotic: bacitracin neutralizes binary bacterial toxins and protects cells from intoxication. FASEB J 2019; 33:5755-5771. [DOI: 10.1096/fj.201802453r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Leonie Schnell
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
| | - Ina Felix
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
| | - Bastian Müller
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
| | - Mirko Sadi
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
| | - Franziska Bank
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
| | | | | | - Klaus Aktories
- Institute of ExperimentalClinical Pharmacology and ToxicologyUniversity of Freiburg Freiburg Germany
| | - Eva Waltenberger
- Department of Life Sciences and ChemistryJacobs University Bremen Bremen Germany
| | - Roland Benz
- Department of Life Sciences and ChemistryJacobs University Bremen Bremen Germany
| | | | - Michael Fauler
- Institute of General PhysiologyUniversity of Ulm Ulm Germany
| | - Manfred Frick
- Institute of General PhysiologyUniversity of Ulm Ulm Germany
| | - Holger Barth
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
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82
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Kandari D, Gopalani M, Gupta M, Joshi H, Bhatnagar S, Bhatnagar R. Identification, Functional Characterization, and Regulon Prediction of the Zinc Uptake Regulator ( zur) of Bacillus anthracis - An Insight Into the Zinc Homeostasis of the Pathogen. Front Microbiol 2019; 9:3314. [PMID: 30687290 PMCID: PMC6336718 DOI: 10.3389/fmicb.2018.03314] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 12/19/2018] [Indexed: 11/29/2022] Open
Abstract
Zinc has an abounding occurrence in the prokaryotes and plays paramount roles including catalytic, structural, and regulatory. Zinc uptake regulator (Zur), a Fur family transcriptional regulator, is connoted in maintaining zinc homeostasis in the pathogenic bacteria by binding to zinc and regulating the genes involved in zinc uptake and mobilization. Zinc homeostasis has been marginally scrutinized in Bacillus anthracis, the top-rated bio-terror agent, with no decipherment of the role of Zur. Of the three Fur family regulators in B. anthracis, BAS4181 is annotated as a zinc-specific transcriptional regulator. This annotation was further substantiated by our stringent computational and experimental analyses. The residues critical for zinc and DNA binding were delineated by homology modeling and sequence/structure analysis. ba zur existed as a part of a three-gene operon. Purified BaZur prodigiously existed in the dimeric form, indicated by size exclusion chromatography and blue native-polyacrylamide gel electrophoresis (PAGE). Computational and manual strategies were employed to decipher the putative regulon of ba zur, comprising of 11 genes, controlled by six promoters, each harboring at least one Zur box. The DNA binding capability of the purified BaZur to the upstream regions of the ba zur operon, yciC, rpmG, znuA, and genes encoding a GTPase cobalamine synthesis protein and a permease was ascertained by electrophoretic mobility shift assays. The regulon genes, implicated in zinc uptake and mobilization, were mostly negatively regulated by BaZur. The ba zur expression was downregulated upon exposure of cells to an excess of zinc. Conversely, it exhibited a marked upregulation under N, N, N', N'-Tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) mediated zinc-depleted environment, adding credence to its negative autoregulation. Moreover, an increase in the transcript levels of the regulon genes znuA, rpmG, and yciC upon exposure of cells to TPEN connoted their role in combating hypo-zincemic conditions by bringing about zinc uptake and mobilization. Thus, this study functionally characterizes Zur of B. anthracis and elucidates its role in maintaining zinc homeostasis.
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Affiliation(s)
- Divya Kandari
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Monisha Gopalani
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Manish Gupta
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Hemant Joshi
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Sonika Bhatnagar
- Computational and Structural Biology Laboratory, Division of Biotechnology, Netaji Subhas Institute of Technology, University of Delhi, New Delhi, India
| | - Rakesh Bhatnagar
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
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83
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Hartmann S, Nusbaum DJ, Kim K, Alameh S, Ho CLC, Cruz RL, Levitin A, Bradley KA, Martchenko M. Role of a Small Molecule in the Modulation of Cell Death Signal Transduction Pathways. ACS Infect Dis 2018; 4:1746-1754. [PMID: 30354048 DOI: 10.1021/acsinfecdis.8b00231] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inflammasomes activate caspase-1 in response to molecular signals from pathogens and other dangerous stimuli as a part of the innate immune response. A previous study discovered a small-molecule, 4-fluoro- N'-[1-(2-pyridinyl)ethylidene]benzohydrazide, which we named DN1, that reduces the cytotoxicity of anthrax lethal toxin (LT). We determined that DN1 protected cells irrespectively of LT concentration and reduced the pathogenicity of an additional bacterial exotoxin and several viruses. Using the LT cytotoxicity pathway, we show that DN1 does not prevent LT internalization and catalytic activity or caspase-1 activation. Moreover, DN1 does not affect the proteolytic activity of host cathepsin B, which facilitates the cytoplasmic entry of toxins. PubChem Bioactivities lists two G protein-coupled receptors (GPCR), type-1 angiotensin II receptor and apelin receptor, as targets of DN1. The inhibition of phosphatidylinositol 3-kinase, phospholipase C, and protein kinase B, which are downstream of GPCR signaling, synergized with DN1 in protecting cells from LT. We hypothesize that DN1-mediated antagonism of GPCRs modulates signal transduction pathways to induce a cellular state that reduces LT-induced pyroptosis downstream of caspase-1 activation. DN1 also reduced the susceptibility of Drosophila melanogaster to toxin-associated bacterial infections. Future experiments will aim to further characterize how DN1 modulates signal transduction pathways to inhibit pyroptotic cell death in LT-sensitive macrophages. DN1 represents a novel chemical probe to investigate host cellular mechanisms that mediate cell death in response to pathogenic agents.
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Affiliation(s)
- Stella Hartmann
- School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Drive, Claremont, California 91711, United States
| | - David J. Nusbaum
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E. Young Drive East, Los Angeles, California 90095, United States
| | - Kevin Kim
- School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Drive, Claremont, California 91711, United States
| | - Saleem Alameh
- School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Drive, Claremont, California 91711, United States
| | - Chi-Lee C. Ho
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E. Young Drive East, Los Angeles, California 90095, United States
| | - Renae L. Cruz
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E. Young Drive East, Los Angeles, California 90095, United States
| | - Anastasia Levitin
- School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Drive, Claremont, California 91711, United States
| | - Kenneth A. Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E. Young Drive East, Los Angeles, California 90095, United States
| | - Mikhail Martchenko
- School of Applied Life Sciences, Keck Graduate Institute, 535 Watson Drive, Claremont, California 91711, United States
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84
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Chapman RN, Liu L, Boons GJ. 4,6- O-Pyruvyl Ketal Modified N-Acetylmannosamine of the Secondary Cell Wall Polysaccharide of Bacillus anthracis Is the Anchoring Residue for Its Surface Layer Proteins. J Am Chem Soc 2018; 140:17079-17085. [PMID: 30452253 DOI: 10.1021/jacs.8b08857] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The secondary cell wall polysaccharide (SCWP) of Bacillus anthracis plays a key role in the organization of the cell envelope of vegetative cells and is intimately involved in host-guest interactions. Genetic studies have indicated that it anchors S-layer and S-layer-associated proteins, which are involved in multiple vital biological functions, to the cell surface of B. anthracis. Phenotypic observations indicate that specific functional groups of the terminal unit of SCWP, including 4,6- O-pyruvyl ketal and acetyl esters, are important for binding of these proteins. These observations are based on genetic manipulations and have not been corroborated by direct binding studies. To address this issue, a synthetic strategy was developed that could provide a range of pyruvylated oligosaccharides derived from B. anthracis SCWP bearing base-labile acetyl esters and free amino groups. The resulting oligosaccharides were used in binding studies with a panel of S-layer and S-layer-associated proteins, which identified structural features of SCWP important for binding. A single pyruvylated ManNAc monosaccharide exhibited strong binding to all proteins, making it a promising structure for S-layer protein manipulation. The acetyl esters and free amine of SCWP did not significantly impact binding, and this observation is contrary to a proposed model in which SCWP acetylation is a prerequisite for association of some but not all S-layer and S-layer-associated proteins.
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Affiliation(s)
- Robert N Chapman
- Complex Carbohydrate Research Center , University of Georgia , Athens , Georgia 30602 , United States.,Department of Chemistry , University of Georgia , Athens , Georgia 30602 , United States
| | - Lin Liu
- Complex Carbohydrate Research Center , University of Georgia , Athens , Georgia 30602 , United States
| | - Geert-Jan Boons
- Complex Carbohydrate Research Center , University of Georgia , Athens , Georgia 30602 , United States.,Department of Chemistry , University of Georgia , Athens , Georgia 30602 , United States.,Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, and Bijvoet Center for Biomolecular Research , Utrecht University , Universiteitsweg 99 , 3584 CG Utrecht , The Netherlands
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85
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A label-free impedimetric aptasensor for the detection of Bacillus anthracis spore simulant. Biosens Bioelectron 2018; 126:640-646. [PMID: 30522085 DOI: 10.1016/j.bios.2018.11.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 12/27/2022]
Abstract
Herein, we report an impedimetric DNA-based aptamer sensor for a single-step detection of B. anthracis spore simulant (B. cereus spore). Specifically, we designed a miniaturized label-free aptasensor for B. cereus spores based on a gold screen-printed electrode functionalized with B. cereus spores-binding aptamer (BAS-6R). Several parameters were optimized to fabricate the aptasensor such as the concentration of DNA aptamer solution (0.5 µM), the time (48 h), the temperature (4 °C), and the pH (7.5) for aptamer immobilization on the working electrode surface. Once the aptasensor was developed, it was tested against B. cereus spores 14579 evaluating the effect of incubation time and MgCl2 concentration. Under the optimized conditions (incubation time equal to 3 h and absence of MgCl2), B. cereus spores 14579 were detected with a linear range between 104 CFU/ml and 5 × 106 CFU/ml and a detection limit of 3 × 103 CFU/ml. Furthermore, the study of selectivity toward B. cereus 11778, B. subtilis, Legionella pneumophila, and Salmonella Typhimurium has demonstrated the capability of this sensor to detect B. cereus spores, proving the suitability of the DNA-based sensing element combined with a portable instrument for a label-free measurement on site of B. anthracis spore simulant.
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86
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Loss of Bacitracin Resistance Due to a Large Genomic Deletion among Bacillus anthracis Strains. mSystems 2018; 3:mSystems00182-18. [PMID: 30417107 PMCID: PMC6208641 DOI: 10.1128/msystems.00182-18] [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: 08/23/2018] [Accepted: 10/04/2018] [Indexed: 12/25/2022] Open
Abstract
Anthrax is caused by Bacillus anthracis, an endospore-forming soil bacterium. The genetic diversity of B. anthracis is known to be low compared with that of Bacillus species. In this study, we performed whole-genome sequencing of Zambian isolates of B. anthracis to understand the genetic diversity between closely related strains. Comparison of genomic sequences revealed that closely related strains were separated into three groups based on single nucleotide polymorphisms distributed throughout the genome. A large genomic deletion was detected in the region containing a bacitracin resistance gene cluster flanked by rRNA operons, resulting in the loss of bacitracin resistance. The structure of the deleted region, which was also conserved among species of the Bacillus cereus group, has the potential for both deletion and amplification and thus might be enabling the species to flexibly control the level of bacitracin resistance for adaptive evolution. Bacillus anthracis is a Gram-positive endospore-forming bacterial species that causes anthrax in both humans and animals. In Zambia, anthrax cases are frequently reported in both livestock and wildlife, with occasional transmission to humans, causing serious public health problems in the country. To understand the genetic diversity of B. anthracis strains in Zambia, we sequenced and compared the genomic DNA of B. anthracis strains isolated across the country. Single nucleotide polymorphisms clustered these strains into three groups. Genome sequence comparisons revealed a large deletion in strains belonging to one of the groups, possibly due to unequal crossing over between a pair of rRNA operons. The deleted genomic region included genes conferring resistance to bacitracin, and the strains with the deletion were confirmed with loss of bacitracin resistance. Similar deletions between rRNA operons were also observed in a few B. anthracis strains phylogenetically distant from Zambian strains. The structure of bacitracin resistance genes flanked by rRNA operons was conserved only in members of the Bacillus cereus group. The diversity and genomic characteristics of B. anthracis strains determined in this study would help in the development of genetic markers and treatment of anthrax in Zambia. IMPORTANCE Anthrax is caused by Bacillus anthracis, an endospore-forming soil bacterium. The genetic diversity of B. anthracis is known to be low compared with that of Bacillus species. In this study, we performed whole-genome sequencing of Zambian isolates of B. anthracis to understand the genetic diversity between closely related strains. Comparison of genomic sequences revealed that closely related strains were separated into three groups based on single nucleotide polymorphisms distributed throughout the genome. A large genomic deletion was detected in the region containing a bacitracin resistance gene cluster flanked by rRNA operons, resulting in the loss of bacitracin resistance. The structure of the deleted region, which was also conserved among species of the Bacillus cereus group, has the potential for both deletion and amplification and thus might be enabling the species to flexibly control the level of bacitracin resistance for adaptive evolution.
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87
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Dupke S, Barduhn A, Franz T, Leendertz FH, Couacy-Hymann E, Grunow R, Klee SR. Analysis of a newly discovered antigen of Bacillus cereus biovar anthracis for its suitability in specific serological antibody testing. J Appl Microbiol 2018; 126:311-323. [PMID: 30253024 DOI: 10.1111/jam.14114] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 08/31/2018] [Accepted: 09/12/2018] [Indexed: 12/21/2022]
Abstract
AIMS The aim of this work was to identify a protein which can be used for specific detection of antibodies against Bacillus cereus biovar anthracis (Bcbva), an anthrax-causing pathogen that so far has been described in African rainforest areas. METHODS AND RESULTS Culture supernatants of Bcbva and classic Bacillus anthracis (Ba) were analysed by gel electrophoresis, and a 35-kDa protein secreted only by Bcbva and not Ba was detected. The protein was identified as pXO2-60 by mass spectrometry. Sequence analysis showed that Ba is unable to secrete this protein due to a premature stop codon in the sequence for the signal peptide. Immunization of five outbred mice with sterile bacterial culture supernatants of Bcbva revealed an immune response in ELISA against pXO2-60 (three mice positive, one borderline) and the protective antigen (PA; four mice). When supernatants of classic Ba were injected into mice or human sera from anthrax patients were analysed, only antibodies against PA were detected. CONCLUSIONS In combination with PA, the pXO2-60 protein can be used for the detection of antibodies specific against Bcbva and discriminating from Ba. SIGNIFICANCE AND IMPACT OF THE STUDY After further validation, serological assays based on pXO2-60 can be used to perform seroprevalence studies to determine the epidemiology of B. cereus bv anthracis in affected countries and assess its impact on the human population.
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Affiliation(s)
- S Dupke
- Robert Koch-Institute, Centre for Biological Threats and Special Pathogens (ZBS2), Berlin, Germany
| | - A Barduhn
- Robert Koch-Institute, Centre for Biological Threats and Special Pathogens (ZBS2), Berlin, Germany
| | - T Franz
- Robert Koch-Institute, Centre for Biological Threats and Special Pathogens (ZBS2), Berlin, Germany
| | - F H Leendertz
- Robert Koch-Institute, Epidemiology of Highly Pathogenic Microorganisms (P3), Berlin, Germany
| | - E Couacy-Hymann
- Laboratoire National d'Appui au Développement Agricole (LANADA), Laboratoire Central Vétérinaire de Bingerville (LCVB), Bingerville, Côte d'Ivoire
| | - R Grunow
- Robert Koch-Institute, Centre for Biological Threats and Special Pathogens (ZBS2), Berlin, Germany
| | - S R Klee
- Robert Koch-Institute, Centre for Biological Threats and Special Pathogens (ZBS2), Berlin, Germany
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88
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Karimi F, Alizadeh S, Alizadeh H. Immunogenicity of multi-walled carbon nanotubes functionalized with recombinant protective antigen domain 4 toward development of a nanovaccine against anthrax. J Drug Deliv Sci Technol 2018. [DOI: 10.1016/j.jddst.2018.07.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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89
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Andreou A, Giastas P, Christoforides E, Eliopoulos EE. Structural and Evolutionary Insights within the Polysaccharide Deacetylase Gene Family of Bacillus anthracis and Bacillus cereus. Genes (Basel) 2018; 9:E386. [PMID: 30065210 PMCID: PMC6115787 DOI: 10.3390/genes9080386] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/24/2018] [Accepted: 07/25/2018] [Indexed: 02/06/2023] Open
Abstract
Functional and folding constraints impose interdependence between interacting sites along the protein chain that are envisaged through protein sequence evolution. Studying the influence of structure in phylogenetic models requires detailed and reliable structural models. Polysaccharide deacetylases (PDAs), members of the carbohydrate esterase family 4, perform mainly metal-dependent deacetylation of O- or N-acetylated polysaccharides such as peptidoglycan, chitin and acetylxylan through a conserved catalytic core termed the NodB homology domain. Genomes of Bacillus anthracis and its relative Bacillus cereus contain multiple genes of putative or known PDAs. A comparison of the functional domains of the recently determined PDAs from B. anthracis and B. cereus and multiple amino acid and nucleotide sequence alignments and phylogenetic analysis performed on these closely related species showed that there were distinct differences in binding site formation, despite the high conservation on the protein sequence, the folding level and the active site assembly. This may indicate that, subject to biochemical verification, the binding site-forming sequence fragments are under functionally driven evolutionary pressure to accommodate and recognize distinct polysaccharide residues according to cell location, use, or environment. Finally, we discuss the suggestion of the paralogous nature of at least two genes of B. anthracis, ba0330 and ba0331, via specific differences in gene sequence, protein structure, selection pressure and available localization patterns. This study may contribute to understanding the mechanisms under which sequences evolve in their structures and how evolutionary processes enable structural variations.
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Affiliation(s)
- Athena Andreou
- Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
| | - Petros Giastas
- Department of Neurobiology, Hellenic Pasteur Institute, Vasilissis Sofias 127, 11521 Athens, Greece.
| | - Elias Christoforides
- Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
| | - Elias E Eliopoulos
- Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
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90
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Certhrax Is an Antivirulence Factor for the Anthrax-Like Organism Bacillus cereus Strain G9241. Infect Immun 2018; 86:IAI.00207-18. [PMID: 29610258 DOI: 10.1128/iai.00207-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 03/28/2018] [Indexed: 11/20/2022] Open
Abstract
Bacillus cereus G9241 caused a life-threatening anthrax-like lung infection in a previously healthy human. This strain harbors two large virulence plasmids, pBCXO1 and pBC210, that are absent from typical B. cereus isolates. The pBCXO1 plasmid is nearly identical to pXO1 from Bacillus anthracis and carries genes (pagA1, lef, and cya) for anthrax toxin components (protective antigen [called PA1 in G9241], lethal factor [LF], and edema factor [EF], respectively). The plasmid also has an intact hyaluronic acid capsule locus. The pBC210 plasmid has a tetrasaccharide capsule locus, a gene for a PA1 homolog called PA2 (pagA2), and a gene (cer) for Certhrax, an ADP-ribosyltransferase toxin that inactivates vinculin. LF, EF, and Certhrax require PA for entry into cells. In this study, we asked what role PA1, PA2, LF, and Certhrax play in the pathogenicity of G9241. To answer this, we generated isogenic deletion mutations in the targeted toxin gene components and then assessed the strains for virulence in highly G9241-susceptible (A/J) and moderately G9241-sensitive (C57BL/6) mice. We found that full virulence of G9241 required PA1 and LF, while PA2 contributed minimally to pathogenesis of G9241 but could not functionally replace PA1 as a toxin-binding subunit in vivo Surprisingly, we discovered that Certhrax attenuated the virulence of G9241; i.e., a Δcer Δlef mutant strain was more virulent than a Δlef mutant strain following subcutaneous inoculation of A/J mice. Moreover, the enzymatic activity of Certhrax contributed to this phenotype. We concluded that Certhrax acts as an antivirulence factor in the anthrax-like organism B. cereus G9241.
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91
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Majumder S, Das S, Somani V, Makam SS, Joseph KJ, Bhatnagar R. A bivalent protein r-PB, comprising PA and BclA immunodominant regions for comprehensive protection against Bacillus anthracis. Sci Rep 2018; 8:7242. [PMID: 29740033 PMCID: PMC5940697 DOI: 10.1038/s41598-018-25502-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 04/23/2018] [Indexed: 01/09/2023] Open
Abstract
Anthrax infection is primarily initiated by B. anthracis endospores that on entry into the host germinate to vegetative cells and cause severe bacteremia and toxaemia employing an array of host colonisation factors and the lethal tripartite toxin. The protective efficacy of conventional protective antigen (PA) based anthrax vaccines is improved by co-administration with inactivated spores or its components. In the present study, using structural vaccinology rationale we synthesized a bivalent protein r-PB encompassing toxin (PAIV) and spore components (BclACTD) and characterized its protective efficacy against B. anthracis infection. Active immunization of mice with r-PB generated high titer circulating antibodies which facilitated the phagocytic uptake of spores, inhibited their germination to vegetative cells and completely neutralized anthrax toxins in vivo resulting in 100 % survival against anthrax toxin challenge. Proliferation of CD4+ T cell subsets with up-regulation of Th1 (IFN-γ, IL-2, and IL-12), Th2 (IL-5, IL-10) cytokines and balanced expression of IgG1:IgG2a antibody isotypes indicated the stimulation of both Th1 and Th2 subsets. The immunized mice exhibited 100 % survival upon challenge with B. anthracis spores or toxin indicating the ability of r-PB to provide comprehensive protection against anthrax. Our results thus demonstrate r-PB an efficient vaccine candidate against anthrax infection.
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Affiliation(s)
- Saugata Majumder
- Microbiology Division, Defence Food Research Laboratory, Defence Research Development Organisation, Mysore, 570011, India
| | - Shreya Das
- Microbiology Division, Defence Food Research Laboratory, Defence Research Development Organisation, Mysore, 570011, India
| | - Vikas Somani
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Shivakiran S Makam
- Microbiology Division, Defence Food Research Laboratory, Defence Research Development Organisation, Mysore, 570011, India
| | - Kingston J Joseph
- Microbiology Division, Defence Food Research Laboratory, Defence Research Development Organisation, Mysore, 570011, India.
| | - Rakesh Bhatnagar
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India
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92
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Lekota KE, Hassim A, Rogers P, Dekker EH, Last R, de Klerk-Lorist L, van Heerden H. The reporting of a Bacillus anthracis B-clade strain in South Africa after more than 20 years. BMC Res Notes 2018; 11:264. [PMID: 29716659 PMCID: PMC5930959 DOI: 10.1186/s13104-018-3366-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 04/20/2018] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVES Anthrax is a disease with an age old history in Africa caused by the Gram-positive endospore forming soil bacterium Bacillus anthracis. Epizootics of wild ungulates occur annually in the enzootic region of Pafuri, Kruger National Park (KNP) in the Limpopo Province of South Africa. Rigorous routine surveillance and diagnostics in KNP, has not revealed these rare isolates since the 1990s, despite unabated annual outbreaks. In 2011 a cheetah was diagnosed as anthrax positive from a private game reserve in Limpopo Province and reported to State Veterinary Services for further investigation. Isolation, molecular diagnostics, whole genome sequencing and comparative genomics were carried out for B. anthracis KC2011. RESULTS Bacteriological and molecular diagnostics confirmed the isolate as B. anthracis. Subsequent typing and whole genome single nucleotide polymorphisms analysis indicated it clustered alongside B. anthracis SA A0091 in the B.Br.010 SNP branch. Unlike B. anthracis KrugerB strain, KC2011 strain has unique SNPs and represents a new branch in the B-clade. The isolation and genotypic characterisation of KC2011 demonstrates a gap in the reporting of anthrax outbreaks in the greater Limpopo province area. The identification of vulnerable and susceptible cheetah mortalities due to this strain has implications for conservation measures and disease control.
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Affiliation(s)
- K E Lekota
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa. .,College of Agriculture and Environmental Sciences, University of South Africa, Christiaan De Wet/Pioneer Dr., Florida, South Africa.
| | - A Hassim
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - P Rogers
- Provet Wildlife Services, Raptors Safari Junction, Main Road, Hoedspruit, South Africa
| | - E H Dekker
- State Veterinary Services, Department of Agriculture, Forestry and Fisheries, Skukuza, South Africa
| | - R Last
- Vetdiagnostix-Veterinary Pathology Services, 257 Boshoff Street, Pietermaritzburg, South Africa
| | - L de Klerk-Lorist
- State Veterinary Services, Department of Agriculture, Forestry and Fisheries, Skukuza, South Africa
| | - H van Heerden
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
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93
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Dale JL, Raynor MJ, Ty MC, Hadjifrangiskou M, Koehler TM. A Dual Role for the Bacillus anthracis Master Virulence Regulator AtxA: Control of Sporulation and Anthrax Toxin Production. Front Microbiol 2018; 9:482. [PMID: 29599764 PMCID: PMC5862856 DOI: 10.3389/fmicb.2018.00482] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/28/2018] [Indexed: 12/02/2022] Open
Abstract
Bacillus anthracis is an endemic soil bacterium that exhibits two different lifestyles. In the soil environment, B. anthracis undergoes a cycle of saprophytic growth, sporulation, and germination. In mammalian hosts, the pathogenic lifestyle of B. anthracis is spore germination followed by vegetative cell replication, but cells do not sporulate. During infection, and in specific culture conditions, transcription of the structural genes for the anthrax toxin proteins and the biosynthetic operon for capsule synthesis is positively controlled by the regulatory protein AtxA. A critical role for the atxA gene in B. anthracis virulence has been established. Here we report an inverse relationship between toxin production and sporulation that is linked to AtxA levels. During culture in conditions favoring sporulation, B. anthracis produces little to no AtxA. When B. anthracis is cultured in conditions favoring toxin gene expression, AtxA is expressed at relatively high levels and sporulation rate and efficiency are reduced. We found that a mutation within the atxA promoter region resulting in AtxA over-expression leads to a marked sporulation defect. The sporulation phenotype of the mutant is dependent upon pXO2-0075, an atxA-regulated open reading frame located on virulence plasmid pXO2. The predicted amino acid sequence of the pXO2-0075 protein has similarity to the sensor domain of sporulation sensor histidine kinases. It was shown previously that pXO2-0075 overexpression suppresses sporulation. We have designated pXO2-0075 “skiA” for “sporulation kinase inhibitor.” Our results indicate that in addition to serving as a positive regulator of virulence gene expression, AtxA modulates B. anthracis development.
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Affiliation(s)
- Jennifer L Dale
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States.,MD Anderson Cancer Center and UTHealth Graduate School of Biomedical Sciences, The University of Texas, Houston, TX, United States
| | - Malik J Raynor
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States.,MD Anderson Cancer Center and UTHealth Graduate School of Biomedical Sciences, The University of Texas, Houston, TX, United States
| | - Maureen C Ty
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Maria Hadjifrangiskou
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States.,MD Anderson Cancer Center and UTHealth Graduate School of Biomedical Sciences, The University of Texas, Houston, TX, United States
| | - Theresa M Koehler
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States.,MD Anderson Cancer Center and UTHealth Graduate School of Biomedical Sciences, The University of Texas, Houston, TX, United States
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94
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Yilmaz MD, Oktem HA. Eriochrome Black T–Eu3+ Complex as a Ratiometric Colorimetric and Fluorescent Probe for the Detection of Dipicolinic Acid, a Biomarker of Bacterial Spores. Anal Chem 2018; 90:4221-4225. [DOI: 10.1021/acs.analchem.8b00576] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- M. Deniz Yilmaz
- Department of Bioengineering, Faculty of Engineering and Architecture, Konya Food and Agriculture University, 42080 Konya, Turkey
- Research and Development Center for Diagnostic Kits (KIT-ARGEM), Konya Food and Agriculture University, 42080 Konya, Turkey
| | - Huseyin Avni Oktem
- Department of Biological Sciences, Middle East Technical University, 06800 Ankara, Turkey
- Nanobiz R&D Ltd., Gallium Bld. No.18, METU Science Park, Ankara, Turkey
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95
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Joon S, Gopalani M, Rahi A, Kulshreshtha P, Gogoi H, Bhatnagar S, Bhatnagar R. Biochemical characterization of the GTP-sensing protein, CodY of Bacillus anthracis. Pathog Dis 2018; 75:3791465. [PMID: 28472295 DOI: 10.1093/femspd/ftx048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 04/22/2017] [Indexed: 12/30/2022] Open
Abstract
The pleiotropism of the GTP-sensing transcriptional regulator CodY is evident by the gamut of processes that it regulates in almost all low G+C Gram-positive bacteria, including general metabolism, biosynthesis of some amino acids and transport systems, nitrogen uptake, sporulation, biofilm formation, motility and virulence. The role of CodY in virulence has been established in Bacillus anthracis, the top rated bioterrorism agent. In this study, we investigated the biochemical attributes of this global regulator. Homology modeling and sequence/structure analysis revealed putative GTP-binding residues in CodY of B. anthracis. CodY exhibited an interaction with the GTP as tested by ultraviolet cross-linking experiments. It could autophosphorylate itself at a conserved Ser215 residue. This was further corroborated by the impairment of autophosphorylation activity in the CodYS215A mutant. Autophosphorylation may be speculated as an additional mechanism regulating CodY activity in the cell. The protein could also hydrolyze GTP, albeit weakly, as indicated by thin- layer chromatography and spectrophotometric quantification of its kinetic parameters. Altogether, these observations provide us an insight into the mechanism of action of this global regulator and a better understanding of its functional regulation.
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Affiliation(s)
- Shikha Joon
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, Munirka, New Delhi 110067, India.,Structural and Computational Biology Laboratory, Department of Biotechnology, Netaji Subhas Institute of Technology, New Delhi 110078, India
| | - Monisha Gopalani
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, Munirka, New Delhi 110067, India
| | - Amit Rahi
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, Munirka, New Delhi 110067, India
| | | | - Himanshu Gogoi
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, Munirka, New Delhi 110067, India
| | - Sonika Bhatnagar
- Structural and Computational Biology Laboratory, Department of Biotechnology, Netaji Subhas Institute of Technology, New Delhi 110078, India
| | - Rakesh Bhatnagar
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, Munirka, New Delhi 110067, India
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96
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Characterisation of the antibacterial properties of the recombinant phage endolysins AP50-31 and LysB4 as potent bactericidal agents against Bacillus anthracis. Sci Rep 2018; 8:18. [PMID: 29311588 PMCID: PMC5758571 DOI: 10.1038/s41598-017-18535-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 12/08/2017] [Indexed: 11/08/2022] Open
Abstract
The recombinant phage endolysins AP50-31 and LysB4 were developed using genetic information from bacteriophages AP50 and B4 and were produced by microbial cultivation followed by chromatographic purification. Subsequently, appropriate formulations were developed that provided an acceptable stability of the recombinant endolysins. The bacteriolytic properties of the formulated endolysins AP50-31 and LysB4 against several bacterial strains belonging to the Bacillus genus including Bacillus anthracis (anthrax) strains were examined. AP50-31 and LysB4 displayed rapid bacteriolytic activity and broad bacteriolytic spectra within the Bacillus genus, including bacteriolytic activity against all the B. anthracis strains tested. When administered intranasally, LysB4 completely protected A/J mice from lethality after infection with the spores of B. anthracis Sterne. When examined at 3 days post-infection, bacterial counts in the major organs (lung, liver, kidney, and spleen) were significantly lower compared with those of the control group that was not treated with endolysin. In addition, histopathological examinations revealed a marked improvement of pathological features in the LysB4-treated group. The results of this study support the idea that phage endolysins are promising candidates for developing therapeutics against anthrax infection.
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Turk BE. Exceptionally Selective Substrate Targeting by the Metalloprotease Anthrax Lethal Factor. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1111:189-203. [PMID: 30267305 DOI: 10.1007/5584_2018_273] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The zinc-dependent metalloprotease anthrax lethal factor (LF) is the enzymatic component of a toxin thought to have a major role in Bacillus anthracis infections. Like many bacterial toxins, LF is a secreted protein that functions within host cells. LF is a highly selective protease that cleaves a limited number of substrates in a site-specific manner, thereby impacting host signal transduction pathways. The major substrates of LF are mitogen-activated protein kinase kinases (MKKs), which lie in the middle of three-component phosphorylation cascades mediating numerous functions in a variety of cells and tissues. How LF targets its limited substrate repertoire has been an active area of investigation. LF recognizes a specific sequence motif surrounding the scissile bonds of substrate proteins. X-ray crystallography of the protease in complex with peptide substrates has revealed the structural basis of selectivity for the LF cleavage site motif. In addition to having interactions proximal to the cleavage site, LF binds directly to a more distal region in its substrates through a so-called exosite interaction. This exosite has been mapped to a surface within a non-catalytic domain of LF with previously unknown function. A putative LF-binding site has likewise been identified on the catalytic domains of MKKs. Here we review our current state of understanding of LF-substrate interactions and discuss the implications for the design and discovery of inhibitors that may have utility as anthrax therapeutics.
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Affiliation(s)
- Benjamin E Turk
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA.
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Ben Rejeb S, Lereclus D, Slamti L. Analysis of abrB Expression during the Infectious Cycle of Bacillus thuringiensis Reveals Population Heterogeneity. Front Microbiol 2017; 8:2471. [PMID: 29312181 PMCID: PMC5732988 DOI: 10.3389/fmicb.2017.02471] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/28/2017] [Indexed: 11/19/2022] Open
Abstract
Using the model host/pathogen pair Galleria mellonella/Bacillus thuringiensis, we have shown that these bacteria could kill their insect host, survive in its cadaver and form spores by sequentially activating virulence, necrotrophism and sporulation genes. However, the population isolated from the cadavers was heterogeneous, including non-sporulating cells in an unknown physiological state. To characterize these bacteria, we used a transcriptional fusion between the promoter of a gene expressed during early exponential growth (abrB) and a reporter gene encoding a destabilized version of GFP, in combination with a fluorescent reporter of the necrotrophic state. The composition of the bacterial population during infection was then analyzed by flow cytometry. We showed that the PabrB promoter was activated in the population that had turned on the necrotrophic reporter, suggesting a re-entry into vegetative growth. Strikingly, the cells that did not go through the necrotrophic state did not activate the PabrB promoter and appear as a dormant subpopulation. We propose a new model describing the B. thuringiensis cell types during infection.
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Affiliation(s)
- Samia Ben Rejeb
- Micalis Institute, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Didier Lereclus
- Micalis Institute, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Leyla Slamti
- Micalis Institute, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
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99
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Gallegos-Candela M, Boyer AE, Woolfitt AR, Brumlow J, Lins RC, Quinn CP, Hoffmaster AR, Meister G, Barr JR. Validated MALDI-TOF-MS method for anthrax lethal factor provides early diagnosis and evaluation of therapeutics. Anal Biochem 2017; 543:97-107. [PMID: 29224733 PMCID: PMC7904043 DOI: 10.1016/j.ab.2017.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/01/2017] [Accepted: 12/06/2017] [Indexed: 01/12/2023]
Abstract
Anthrax lethal factor (LF) is a zinc-dependent endoprotease and a critical virulence factor for Bacillus anthracis, the causative agent of anthrax. The mass spectrometry (MS) method for total-LF quantification includes three steps; 1) LF specific antibody capture/concentration, 2) LF-specific hydrolysis of a peptide substrate, and 3) detection and quantification of LF-cleaved peptides by isotope-dilution MALDI-TOF/MS. Recombinant LF spiked plasma was used for calibration and quality control (QC) materials. Specificity was 100% from analysis of serum and plasma from 383 non-infected humans, 31 rabbits, and 24 rhesus macaques. Sensitivity was 100% from 32 human clinical anthrax cases including infections by inhalation, ingestion, cutaneous and injection exposures and experimental infections for 29 rabbits and 24 rhesus macaques with inhalation anthrax. Robustness evaluation included sample storage, serum and plasma, antimicrobial and antitoxin effects and long-term performance. Data from 100 independent runs gave detection limits 0.01 ng/mL (111 amol/mL) for the 4-h method and 0.0027 ng/mL (30 amol/mL) for an alternate 20-h method. QC precision ranged from 7.7 to 14.8% coefficient of variation and accuracy from 0.2 to 9.8% error. The validated LF MS method provides sensitive quantification of anthrax total-LF using a robust high throughput platform for early diagnosis and evaluation of therapeutics during an anthrax emergency.
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Affiliation(s)
- Maribel Gallegos-Candela
- Centers for Disease Control and Prevention, 4770 Buford Highway Mailstop F-50, Atlanta, GA 30341, USA
| | - Anne E Boyer
- Centers for Disease Control and Prevention, 4770 Buford Highway Mailstop F-50, Atlanta, GA 30341, USA.
| | - Adrian R Woolfitt
- Centers for Disease Control and Prevention, 4770 Buford Highway Mailstop F-50, Atlanta, GA 30341, USA
| | - Judy Brumlow
- Battelle Atlanta Analytical Services, 2987 Clairmont Road NE, Suite 450, Atlanta, GA 30329, USA
| | - Renato C Lins
- Battelle Atlanta Analytical Services, 2987 Clairmont Road NE, Suite 450, Atlanta, GA 30329, USA
| | - Conrad P Quinn
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA
| | - Alex R Hoffmaster
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA
| | - Gabriel Meister
- Battelle Biomedical Research Center, 1425 Plain City Georgesville Rd, West Jefferson, OH 43162, USA
| | - John R Barr
- Centers for Disease Control and Prevention, 4770 Buford Highway Mailstop F-50, Atlanta, GA 30341, USA
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100
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Nagy CF, Leach TS, King A, Guttendorf R. Safety, Pharmacokinetics, and Immunogenicity of Obiltoxaximab After Intramuscular Administration to Healthy Humans. Clin Pharmacol Drug Dev 2017; 7:652-660. [PMID: 29125719 PMCID: PMC6668011 DOI: 10.1002/cpdd.410] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 09/24/2017] [Indexed: 12/15/2022]
Abstract
Inhalational anthrax is a highly lethal infection caused by Bacillus anthracis and a serious bioterrorism threat. Protective antigen (PA) is a critical component required for the virulence of Bacillus anthracis. Obiltoxaximab, a high‐affinity monoclonal antibody that neutralizes PA, is approved in the United States for intravenous use for the treatment of inhalational anthrax in combination with appropriate antibacterial drugs and for prophylaxis of inhalational anthrax when alternative therapies are not available or appropriate. Here, we explored the safety, pharmacokinetics (PK), and immunogenicity of obiltoxaximab administered by intramuscular injection at doses of 4, 8, 16, 20, and 24 mg/kg in healthy humans. Systemic exposures were approximately dose proportional, maximum serum concentrations were observed after 6–9 days, and terminal half‐life ranged from 16 to 23 days. Average absolute intramuscular bioavailability was 64%. Obiltoxaximab was well tolerated, and local tolerability was acceptable up to 24 mg/kg intramuscularly, up to 6 injections per dose, and up to 5 mL per injection. No injection‐site abscesses or hypersensitivity reactions occurred; no subjects developed treatment‐emergent antitherapeutic antibodies over the study period of 71 days.
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Affiliation(s)
- Christa F Nagy
- Department of Clinical Operations, Elusys Therapeutics, Inc., Pine Brook, NJ, USA
| | | | - Alex King
- Covance Clinical Research Unit, Inc., Dallas, TX, USA
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