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Kim SH, Lee JI, Kang DH. Effects of Na + adaptation on Bacillus cereus endospores inactivation and transcriptome changes. Food Res Int 2024; 195:114975. [PMID: 39277241 DOI: 10.1016/j.foodres.2024.114975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 08/20/2024] [Accepted: 08/20/2024] [Indexed: 09/17/2024]
Abstract
As Bacillus cereus endospores exist in various vegetables grown in soil, the possibility of contamination in food products with high salt concentrations cannot be ignored. Recent studies revealed that harsh conditions affect the resistance of bacteria; thus, we investigated the developmental aspect of heat resistance of B. cereus after sporulation with high NaCl concentration. RNA sequencing was conducted for transcriptomic changes when B. cereus endospores formed at high salinity, and membrane fluidity and hydrophobicity were measured to verify the transcriptomic analysis. Our data showed that increasing NaCl concentration in sporulation media led to a decrease in heat resistance. Also, endospore hydrophobicity, membrane fluidity, and endospore density decreased with sporulation at higher NaCl concentrations. When the transcript changes of B. cereus sporulated at NaCl concentrations of 0.5 and 7% were analyzed by transcriptome analysis, it was confirmed that the NaCl 7% endospores had significantly lower expression levels (FDR<0.05) of genes related to sporulation stages 3 and 4, which led to a decrease in expression of spore-related genes such as coat proteins and small acid-soluble proteins. Our findings indicated that high NaCl concentrations inhibited sporulation stages 3 and 4, thereby preventing proper cell maturation in the forespores and adequate formation of the coat protein and cortex. This inhibition led to decreased endospore density and hydrophobicity, ultimately resulting in reduced heat resistance.resistanceWe expect that this study will be utilized as a baseline for further studies and enhance sterilization strategies.
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Affiliation(s)
- Soo-Hwan Kim
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Jae-Ik Lee
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Dong-Hyun Kang
- Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gangwon-do 25354, Republic of Korea.
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2
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Rolfe CA, Morrissey TR, Redan BW, Aguilar VL, Skinner GE, Reddy NR. Role of Dipicolinic Acid in Heat Resistance of Spores of Clostridium botulinum and Clostridium sporogenes PA3679 by Thermal and Pressure-assisted Thermal Processing. J Food Prot 2024; 87:100359. [PMID: 39260571 DOI: 10.1016/j.jfp.2024.100359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 08/06/2024] [Accepted: 09/05/2024] [Indexed: 09/13/2024]
Abstract
Dipicolinic acid (DPA) is a major constituent of spores and reportedly provides protection against inactivation by various thermal processes; however, the relationship between DPA and resistance towards pressure-assisted thermal processing is not well understood. Thermal and pressure-assisted thermal inactivation studies of Clostridium botulinum nonproteolytic strains QC-B and 610-F, proteolytic strain Giorgio-A, and thermal surrogate Clostridium sporogenes PA3679 spores suspended in ACES buffer (0.05 M, pH 7.0) were performed to determine if a relationship exists between DPA release and log reduction of spores. Thermal inactivation at 80, 83, and 87 °C for nonproteolytic strains and 101, 105, and 108 °C for the proteolytic strain and thermal surrogate were conducted. Pressure-assisted thermal inactivation for nonproteolytic strains at 83 °C/600 MPa and for the proteolytic strain and thermal surrogate at 105 °C/600 MPa were performed. Surviving spores were enumerated by 5-tube MPN method for log reductions and analyzed for released DPA by liquid chromatography-tandem mass spectrometry. The correlation between MPN log reductions, released DPA, and D-values were calculated. A positive correlation between released DPA and log reduction of spores was observed for QC-B and 610-F at 80 and 83 °C (r = 0.6073 - 0.7755; P < 0.01). At 87 °C, a positive correlation was detected for 610-F (r = 0.4242, P < 0.05) and no correlation was observed for QC-B (r = 0.1641; P > 0.05). A strong, positive correlation (r = 0.8359 - 0.9284; P < 0.05) between released DPA and log reduction of spores was observed for Giorgio-A at 101, 105, and 108 °C, and a strong, positive correlation (r = 0.8402; P < 0.05) was observed for PA3679 at 101 °C. A positive correlation (r = 0.5646 - 0.6724; P < 0.01) was observed for QC-B, 610-F, and Giorgio-A after pressure-assisted thermal treatment. No correlation (r = 02494; P > 0.05) was found for PA3679 after pressure-assisted thermal treatment. These results suggest a correlation exists between DPA release and heat resistance; however, the level of correlation varied between strains and temperatures. The findings from this research may aid in the development of spore inactivation strategies targeting the thermal resistance profiles of various strains of C. botulinum spores.
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Affiliation(s)
- Catherine A Rolfe
- U. S. Food and Drug Administration, Office of Food Safety, Division of Food Processing Science and Technology, Bedford Park, IL 60501, United States.
| | - Travis R Morrissey
- U. S. Food and Drug Administration, Office of Food Safety, Division of Food Processing Science and Technology, Bedford Park, IL 60501, United States
| | - Benjamin W Redan
- U. S. Food and Drug Administration, Office of Dietary Supplement Programs, Division of Policy and Regulation Implementation, College Park, MD 20740, United States; Food Process Evaluation Team, College Park, MD 20740, United States
| | - Viviana L Aguilar
- Institute for Food Safety and Health, Illinois Institute of Technology, Bedford Park, IL 60501, United States
| | - Guy E Skinner
- U. S. Food and Drug Administration, Office of Food Safety, Multi-Component Foods, College Park, MD 20740, United States
| | - N Rukma Reddy
- U. S. Food and Drug Administration, Office of Food Safety, Division of Food Processing Science and Technology, Bedford Park, IL 60501, United States
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Khanal S, Kim TD, Begyn K, Duverger W, Kramer G, Brul S, Rajkovic A, Devlieghere F, Heyndrickx M, Schymkowitz J, Rousseau F, Broussolle V, Michiels C, Aertsen A. Mechanistic insights into the adaptive evolvability of spore heat resistance in Bacillus cereus sensu lato. Int J Food Microbiol 2024; 418:110709. [PMID: 38663147 DOI: 10.1016/j.ijfoodmicro.2024.110709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 03/09/2024] [Accepted: 04/13/2024] [Indexed: 05/27/2024]
Abstract
Wet heat treatment is a commonly applied method in the food and medical industries for the inactivation of microorganisms, and bacterial spores in particular. While many studies have delved into the mechanisms underlying wet heat killing and spore resistance, little attention has so far been dedicated to the capacity of spore-forming bacteria to tune their resistance through adaptive evolution. Nevertheless, a recent study from our group revealed that a psychrotrophic strain of the Bacillus cereus sensu lato group (i.e. Bacillus weihenstephanensis LMG 18989) could readily and reproducibly evolve to acquire enhanced spore wet heat resistance without compromising its vegetative cell growth ability at low temperatures. In the current study, we demonstrate that another B. cereus strain (i.e. the mesophilic B. cereus sensu stricto ATCC 14579) can acquire significantly increased spore wet heat resistance as well, and we subjected both the previously and currently obtained mutants to whole genome sequencing. This revealed that five out of six mutants were affected in genes encoding regulators of the spore coat and exosporium pathway (i.e. spoIVFB, sigK and gerE), with three of them being affected in gerE. A synthetically constructed ATCC 14579 ΔgerE mutant likewise yielded spores with increased wet heat resistance, and incurred a compromised spore coat and exosporium. Further investigation revealed significantly increased spore DPA levels and core dehydration as the likely causes for the observed enhanced spore wet heat resistance. Interestingly, deletion of gerE in Bacillus subtilis 168 did not impose increased spore wet heat resistance, underscoring potentially different adaptive evolutionary paths in B. cereus and B. subtilis.
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Affiliation(s)
- Sadhana Khanal
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, KU Leuven, Leuven, Belgium
| | - Tom Dongmin Kim
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, KU Leuven, Leuven, Belgium
| | - Katrien Begyn
- Research Unit Food Microbiology and Food Preservation (FMFP-UGent), Department of Food Technology, Safety and Health, Part of Food2Know, Faculty Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Wouter Duverger
- Switch Laboratory, VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, box 802, 3000 Leuven, Belgium
| | - Gertjan Kramer
- Laboratory for Mass Spectrometry of Biomolecules, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098XH Amsterdam, the Netherlands
| | - Stanley Brul
- Molecular Biology & Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098XH Amsterdam, the Netherlands
| | - Andreja Rajkovic
- Research Unit Food Microbiology and Food Preservation (FMFP-UGent), Department of Food Technology, Safety and Health, Part of Food2Know, Faculty Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Frank Devlieghere
- Research Unit Food Microbiology and Food Preservation (FMFP-UGent), Department of Food Technology, Safety and Health, Part of Food2Know, Faculty Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Marc Heyndrickx
- ILVO - Flanders Research Institute for Agriculture, Fisheries and Food, Technology and Food Science, Unit - Food Safety, Melle, Belgium; Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Joost Schymkowitz
- Switch Laboratory, VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, box 802, 3000 Leuven, Belgium
| | - Frederic Rousseau
- Switch Laboratory, VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium; Switch Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, box 802, 3000 Leuven, Belgium
| | | | - Chris Michiels
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, KU Leuven, Leuven, Belgium
| | - Abram Aertsen
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, KU Leuven, Leuven, Belgium..
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Sundaresan A, Cheong I. Elucidating Bacterial Spore Dynamics through Lanthanide-Enhanced Live Imaging. ACS Sens 2024; 9:789-798. [PMID: 38221734 DOI: 10.1021/acssensors.3c02083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Identifying and distinguishing dormant and active bacterial spores are vital for biosecurity, food safety, and space exploration. Yet, there is a lack of simple, quick, and nondestructive methods to achieve this. The common Schaeffer-Fulton method is both sample-destructive and requires significant operator involvement. In this study, we employed lanthanide-beta-diketonate complexes to directly observe both dormant and germinated single spores. Staining is instantaneous and requires minimal sample processing. The complex stains areas outside the core of dormant spores, leaving the core hollow and nonfluorescent. However, upon germination, the complex enters the core, making it brightly fluorescent. This difference was noted in five bacterial species including Bacillus, Clostridium, and Clostridioides. Various lanthanides and beta-diketonates can be mixed to form a range of spore-visualizing complexes. Due to their low toxicity, these complexes allow for live imaging of single germinating spores. We demonstrate low-cost imaging using a USB microscope as well as imaging of spores in milk matrices. This method provides a valuable tool for studying bacterial spores.
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Affiliation(s)
- Ajitha Sundaresan
- Temasek Life Sciences Laboratory, National University of Singapore, 117604 Singapore
- Department of Biological Sciences, National University of Singapore, 117558 Singapore
| | - Ian Cheong
- Temasek Life Sciences Laboratory, National University of Singapore, 117604 Singapore
- Department of Biological Sciences, National University of Singapore, 117558 Singapore
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5
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Ning Z, Dong W, Bian Z, Huang H, Hong K. Insight into effects of terbium on cell growth, sporulation and spore properties of Bacillus subtilis. World J Microbiol Biotechnol 2024; 40:79. [PMID: 38281285 DOI: 10.1007/s11274-024-03904-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 01/19/2024] [Indexed: 01/30/2024]
Abstract
Recovery of rare earth elements (REEs) from wastewater with Bacillus subtilis (B. subtilis) during culture is promising due to its environmental benefits. However, the effects of REEs in the culture media on B. subtilis are poorly understood. This study aims to investigate the effects of the terbium (Tb(III)), a typical rare earth element, on the cell growth, sporulation, and spore properties of B. subtilis. Tb(III) can suppress bacterial growth while enhancing spore tolerance to wet heat. Spore germination and content of dipicolinic acid (DPA) were promoted at low concentrations of Tb(III) while inhibited at a high level, but an inverse effect on initial sporulation appeared. Scanning electron microscope and energy dispersive spectrometer detection indicated that Tb(III) complexed cells or spores and certain media components simultaneously. The germination results of the spores after elution revealed that Tb(III) attached to the spore surface was a key effector of spore germination. In conclusion, Tb(III) directly or indirectly regulated both the nutrient status of the media and certain metabolic events, which in turn affected most of the properties of B. subtilis. Compared to the coat-deficient strain, the wild-type strain grew faster and was more tolerant to Tb(III), DPA, and wet heat, which in turn implied that it was more suitable for the recovery of REEs during cultivation. These findings provide fundamental insights for the recovery of rare earths during the culture process using microorganisms.
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Affiliation(s)
- Zhoushen Ning
- Jiangxi Provincial Key Laboratory of Environmental Pollution Prevention and Control in Mining and Metallurgy, Ganzhou, 341000, China
- School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou, 341000, China
| | - Wei Dong
- Jiangxi Provincial Key Laboratory of Environmental Pollution Prevention and Control in Mining and Metallurgy, Ganzhou, 341000, China.
- Yichun Lithium New Energy Industry Research Institute, Jiangxi University of Science and Technology, Yichun, 336023, China.
- School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou, 341000, China.
- School of Life Sciences, Jiangxi University of Science and Technology, Ganzhou, 341000, China.
| | - Zijun Bian
- Jiangxi Provincial Key Laboratory of Environmental Pollution Prevention and Control in Mining and Metallurgy, Ganzhou, 341000, China
- School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou, 341000, China
| | - Huihong Huang
- School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou, 341000, China
| | - Kemin Hong
- School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou, 341000, China
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Abstract
Clostridioides difficile spores are the infective form for this endospore-forming organism. The vegetative cells are intolerant to oxygen and poor competitors with a healthy gut microbiota. Therefore, in order for C. difficile to establish infection, the spores have to germinate in an environment that supports vegetative growth. To initiate germination, C. difficile uses Csp-type germinant receptors that consist of the CspC and CspA pseudoproteases as the bile acid and cogerminant receptors, respectively. CspB is a subtilisin-like protease that cleaves the inhibitory propeptide from the pro-SleC cortex lytic enzyme, thereby activating it and initiating cortex degradation. Though several locations have been proposed for where these proteins reside within the spore (i.e., spore coat, outer spore membrane, cortex, and inner spore membrane), these have been based, mostly, on hypotheses or prior data in Clostridium perfringens. In this study, we visualized the germination and outgrowth process using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and used immunogold labeling to visualize key germination regulators. These analyses localize these key regulators to the spore cortex region for the first time. IMPORTANCE Germination by C. difficile spores is the first step in the establishment of potentially life-threatening C. difficile infection (CDI). A deeper understanding of the mechanism by which spores germinate may provide insight for how to either prevent spore germination into a disease-causing vegetative form or trigger germination prematurely when the spore is either in the outside environment or in a host environment that does not support the establishment of colonization/disease.
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7
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Chromiková Z, Chovanová RK, Tamindžija D, Bártová B, Radnović D, Bernier-Latmani R, Barák I. Implantation of Bacillus pseudomycoides Chromate Transporter Increases Chromate Tolerance in Bacillus subtilis. Front Microbiol 2022; 13:842623. [PMID: 35330768 PMCID: PMC8940164 DOI: 10.3389/fmicb.2022.842623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/14/2022] [Indexed: 11/23/2022] Open
Abstract
Chromium of anthropogenic origin contaminates the environment worldwide. The toxicity of chromium, a group I human carcinogen, is greatest when it is in a hexavalent oxidation state, Cr(VI). Cr(VI) is actively transported into the cell, triggering oxidative damage intracellularly. Due to the abundance of unspecific intracellular reductants, any microbial species is capable of bio-transformation of toxic Cr(VI) to innocuous Cr(III), however, this process is often lethal. Only some bacterial species are capable of sustaining the vegetative growth in the presence of a high concentration of Cr(VI) and thus operate as self-sustainable bioremediation agents. One of the successful microbial Cr(VI) detoxification strategies is the activation of chromate efflux pumps. This work describes transplantation of the chromate efflux pump from the potentially pathogenic but highly Cr resistant Bacillus pseudomycoides environmental strain into non-pathogenic but only transiently Cr tolerant Bacillus subtilis strain. In our study, we compared the two Bacillus spp. strains harboring evolutionarily diverged chromate efflux proteins. We have found that individual cells of the Cr-resistant B. pseudomycoides environmental strain accumulate less Cr than the cells of B. subtilis strain. Further, we found that survival of the B. subtilis strain during the Cr stress can be increased by the introduction of the chromate transporter from the Cr resistant environmental strain into its genome. Additionally, the expression of B. pseudomycoides chromate transporter ChrA in B. subtilis seems to be activated by the presence of chromate, hinting at versatility of Cr-efflux proteins. This study outlines the future direction for increasing the Cr-tolerance of non-pathogenic species and safe bioremediation using soil bacteria.
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Affiliation(s)
- Zuzana Chromiková
- Department of Microbial Genetics, Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
- *Correspondence: Zuzana Chromiková,
| | - Romana Kalianková Chovanová
- Department of Microbial Genetics, Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Dragana Tamindžija
- Department of Chemistry, Faculty of Sciences, Biochemistry and Environmental Protection, Novi Sad, Serbia
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| | - Barbora Bártová
- Environmental Microbiology Laboratory, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Dragan Radnović
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia
| | - Rizlan Bernier-Latmani
- Environmental Microbiology Laboratory, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Imrich Barák
- Department of Microbial Genetics, Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
- Imrich Barák,
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An Evaluation of Sporicidal Treatments against Blown Pack Spoilage Associated Clostridium estertheticum and Clostridium gasigenes Spores. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12031663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Blown pack spoilage (BPS) occurs when meat is cross-contaminated with Clostridium estertheticum or Clostridium gasigenes spores, often from the meat processing environment. This study tested the efficacy of four sporicidal disinfectants commonly used in beef processing plants against C. estertheticum and C. gasigenes spores in a suspension test. D-values were obtained under model ‘clean’ (sterile distilled water, SDW) and ‘dirty’ (3 g/L bovine serum albumin, BSA) conditions. Mean concentration (log10 CFU/mL) were calculated from direct counts. The levels of dipicolinic acid (DPA), indicating damage to the core of these spores, was also monitored using a terbium (Tb)-DPA assay for treatment 1 (peracetic acid as the active ingredient) in SDW and BSA. In SDW sporicidal treatment 3 (containing peroxymonosulphate) was the most effective against C. estertheticum spores but under ‘dirty’ (BSA) conditions sporicidal treatments 1 and 2 were more effective. A similar pattern was obtained with C. gasigenes with treatment 3 being the most effective in SDW but treatment 2 (sodium hypochlorite as the active ingredient) being more effective in BSA. The lower DPA concentrations obtained in SDW versus BSA demonstrated the protective effect of organic matter. It was concluded that meat processors should use a 5% formulation containing sodium hypochlorite, sodium hydroxide and alkylamine oxide to eliminate BPS Clostridial spores in the abattoir.
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Baloh M, Sorg JA. Clostridioides difficile spore germination: initiation to DPA release. Curr Opin Microbiol 2022; 65:101-107. [PMID: 34808546 PMCID: PMC8792321 DOI: 10.1016/j.mib.2021.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 11/01/2021] [Accepted: 11/04/2021] [Indexed: 02/03/2023]
Abstract
Germination by Clostridioides difficile spores is an essential step in pathogenesis. Spores are metabolically dormant forms of bacteria that resist severe conditions. Work over the last 10 years has elucidated that C. difficile spores germinate thorough a novel pathway. This review summarizes our understanding of C. difficile spore germination and the factors involved in germinant recognition, cortex degradation and DPA release.
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Affiliation(s)
- Marko Baloh
- Department of Biology, Texas A&M University, College Station, TX 77843
| | - Joseph A. Sorg
- Department of Biology, Texas A&M University, College Station, TX 77843,Corresponding author: ph: 979-845-6299,
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Insights into the Structure and Protein Composition of Moorella thermoacetica Spores Formed at Different Temperatures. Int J Mol Sci 2022; 23:ijms23010550. [PMID: 35008975 PMCID: PMC8745062 DOI: 10.3390/ijms23010550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 02/01/2023] Open
Abstract
The bacterium Moorella thermoacetica produces the most heat-resistant spores of any spoilage-causing microorganism known in the food industry. Previous work by our group revealed that the resistance of these spores to wet heat and biocides was lower when spores were produced at a lower temperature than the optimal temperature. Here, we used electron microcopy to characterize the ultrastructure of the coat of the spores formed at different sporulation temperatures; we found that spores produced at 55 °C mainly exhibited a lamellar inner coat tightly associated with a diffuse outer coat, while spores produced at 45 °C showed an inner and an outer coat separated by a less electron-dense zone. Moreover, misarranged coat structures were more frequently observed when spores were produced at the lower temperature. We then analyzed the proteome of the spores obtained at either 45 °C or 55 °C with respect to proteins putatively involved in the spore coat, exosporium, or in spore resistance. Some putative spore coat proteins, such as CotSA, were only identified in spores produced at 55 °C; other putative exosporium and coat proteins were significantly less abundant in spores produced at 45 °C. Altogether, our results suggest that sporulation temperature affects the structure and protein composition of M. thermoacetica spores.
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11
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Huang Y, Flint SH, Palmer JS. The heat resistance of spores from biofilms of Bacillus cereus grown in tryptic soy broth and milk. Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2021.105169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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12
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Swanson J, Navarrette A, Hazelton C, Richmann M, Stanley F. Biomass and salt-dependent effects of Bacillus spores on radionuclide migration from the Waste Isolation Pilot Plant. CHEMOSPHERE 2021; 280:130680. [PMID: 34162079 DOI: 10.1016/j.chemosphere.2021.130680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 06/13/2023]
Abstract
Spores of a Bacillus sp., isolated from radioactive waste, were tested for their ability to influence the fate and transport of neodymium (Nd3+) under high salt conditions expected at the Waste Isolation Pilot Plant (WIPP) nuclear waste repository. Spores were suspended in neodymium-spiked saline solutions up to 4 M NaCl, and concentrations of Nd and the complexing agent dipicolinic acid (DPA), a component of spores, were monitored along with optical densities and spore numbers. Results support neodymium bioassociation that is dependent upon biomass, with more apparent adsorption occurring at higher spore concentrations. However, probable spore lysis in 2 and 4 M NaCl solutions and possible germination at 0.15 M NaCl appear to drive the release of DPA and subsequent return of Nd to solution. The implications of this work for the WIPP will depend on actual biomass levels and the ionic strength of the repository brines.
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Affiliation(s)
- Juliet Swanson
- Los Alamos National Laboratory-Carlsbad Operations, 1400 University Drive, Carlsbad, NM, 88220, USA.
| | - Adrianne Navarrette
- Los Alamos National Laboratory-Carlsbad Operations, 1400 University Drive, Carlsbad, NM, 88220, USA
| | - Cindi Hazelton
- Los Alamos National Laboratory-Carlsbad Operations, 1400 University Drive, Carlsbad, NM, 88220, USA
| | - Michael Richmann
- Los Alamos National Laboratory-Carlsbad Operations, 1400 University Drive, Carlsbad, NM, 88220, USA
| | - Floyd Stanley
- Los Alamos National Laboratory-Carlsbad Operations, 1400 University Drive, Carlsbad, NM, 88220, USA
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Opportunities for Nanomedicine in Clostridioides difficile Infection. Antibiotics (Basel) 2021; 10:antibiotics10080948. [PMID: 34438998 PMCID: PMC8388953 DOI: 10.3390/antibiotics10080948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 12/19/2022] Open
Abstract
Clostridioides difficile, a spore-forming bacterium, is a nosocomial infectious pathogen which can be found in animals as well. Although various antibiotics and disinfectants were developed, C. difficile infection (CDI) remains a serious health problem. C. difficile spores have complex structures and dormant characteristics that contribute to their resistance to harsh environments, successful transmission and recurrence. C. difficile spores can germinate quickly after being exposed to bile acid and co-germinant in a suitable environment. The vegetative cells produce endospores, and the mature spores are released from the hosts for dissemination of the pathogen. Therefore, concurrent elimination of C. difficile vegetative cells and inhibition of spore germination is essential for effective control of CDI. This review focused on the molecular pathogenesis of CDI and new trends in targeting both spores and vegetative cells of this pathogen, as well as the potential contribution of nanotechnologies for the effective management of CDI.
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Ultraviolet-C inactivation and hydrophobicity of Bacillus subtilis and Bacillus velezensis spores isolated from extended shelf-life milk. Int J Food Microbiol 2021; 349:109231. [PMID: 34022614 DOI: 10.1016/j.ijfoodmicro.2021.109231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 03/31/2021] [Accepted: 04/25/2021] [Indexed: 11/23/2022]
Abstract
Bacterial spores are important in food processing due to their ubiquity, resistance to high temperature and chemical inactivation. This work aims to study the effect of ultraviolet C (UVC) on the spores of Bacillus subtilis and Bacillus velezensis at a molecular and individual level to guide in deciding on the right parameters that must be applied during the processing of liquid foods. The spores were treated with UVC using phosphate buffer saline (PBS) as a suspension medium and their lethality rate was determined for each sample. Purified spore samples of B. velezensis and B. subtilis were treated under one pass in a UVC reactor to inactivate the spores. The resistance pattern of the spores to UVC treatment was determined using dipicolinic acid (Ca-DPA) band of spectral analysis obtained from Raman spectroscopy. Flow cytometry analysis was also done to determine the effect of the UVC treatment on the spore samples at the molecular level. Samples were processed for SEM and the percentage spore surface hydrophobicity was also determined using the Microbial Adhesion to Hydrocarbon (MATH) assay to predict the adhesion strength to a stainless-steel surface. The result shows the maximum lethality rate to be 6.5 for B. subtilis strain SRCM103689 (B47) and highest percentage hydrophobicity was 54.9% from the sample B. velezensis strain LPL-K103 (B44). The difference in surface hydrophobicity for all isolates was statistically significant (P < 0.05). Flow cytometry analysis of UVC treated spore suspensions clarifies them further into sub-populations unaccounted for by plate counting on growth media. The Raman spectroscopy identified B4002 as the isolate possessing the highest concentration of Ca-DPA. The study justifies the critical role of Ca-DPA in spore resistance and the possible sub-populations after UVC treatment that may affect product shelf-life and safety. UVC shows a promising application in the inactivation of resistant spores though there is a need to understand the effects at the molecular level to design the best parameters during processing.
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15
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Kumar M, Flint S, Palmer J, Plieger P. A comparison of the spore heat resistance of dairy isolates of Geobacillus stearothermophilus obtained using a CDC biofilm reactor and a sporulating medium. Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2021.105000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Diallo M, Kengen SWM, López-Contreras AM. Sporulation in solventogenic and acetogenic clostridia. Appl Microbiol Biotechnol 2021; 105:3533-3557. [PMID: 33900426 PMCID: PMC8102284 DOI: 10.1007/s00253-021-11289-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/03/2021] [Accepted: 04/07/2021] [Indexed: 02/07/2023]
Abstract
The Clostridium genus harbors compelling organisms for biotechnological production processes; while acetogenic clostridia can fix C1-compounds to produce acetate and ethanol, solventogenic clostridia can utilize a wide range of carbon sources to produce commercially valuable carboxylic acids, alcohols, and ketones by fermentation. Despite their potential, the conversion by these bacteria of carbohydrates or C1 compounds to alcohols is not cost-effective enough to result in economically viable processes. Engineering solventogenic clostridia by impairing sporulation is one of the investigated approaches to improve solvent productivity. Sporulation is a cell differentiation process triggered in bacteria in response to exposure to environmental stressors. The generated spores are metabolically inactive but resistant to harsh conditions (UV, chemicals, heat, oxygen). In Firmicutes, sporulation has been mainly studied in bacilli and pathogenic clostridia, and our knowledge of sporulation in solvent-producing or acetogenic clostridia is limited. Still, sporulation is an integral part of the cellular physiology of clostridia; thus, understanding the regulation of sporulation and its connection to solvent production may give clues to improve the performance of solventogenic clostridia. This review aims to provide an overview of the triggers, characteristics, and regulatory mechanism of sporulation in solventogenic clostridia. Those are further compared to the current knowledge on sporulation in the industrially relevant acetogenic clostridia. Finally, the potential applications of spores for process improvement are discussed.Key Points• The regulatory network governing sporulation initiation varies in solventogenic clostridia.• Media composition and cell density are the main triggers of sporulation.• Spores can be used to improve the fermentation process.
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Affiliation(s)
- Mamou Diallo
- Wageningen Food and Biobased Research, Wageningen, The Netherlands.
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands.
| | - Servé W M Kengen
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
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17
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Diallo M, Kint N, Monot M, Collas F, Martin-Verstraete I, van der Oost J, Kengen SWM, López-Contreras AM. Transcriptomic and Phenotypic Analysis of a spoIIE Mutant in Clostridium beijerinckii. Front Microbiol 2020; 11:556064. [PMID: 33042064 PMCID: PMC7522474 DOI: 10.3389/fmicb.2020.556064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/20/2020] [Indexed: 11/26/2022] Open
Abstract
SpoIIE is a phosphatase involved in the activation of the first sigma factor of the forespore, σ F , during sporulation. A ΔspoIIE mutant of Clostridium beijerinckii NCIMB 8052, previously generated by CRISPR-Cas9, did not sporulate but still produced granulose and solvents. Microscopy analysis also showed that the cells of the ΔspoIIE mutant are elongated with the presence of multiple septa. This observation suggests that in C. beijerinckii, SpoIIE is necessary for the completion of the sporulation process, as seen in Bacillus and Clostridium acetobutylicum. Moreover, when grown in reactors, the spoIIE mutant produced higher levels of solvents than the wild type strain. The impact of the spoIIE inactivation on gene transcription was assessed by comparative transcriptome analysis at three time points (4 h, 11 h and 23 h). Approximately 5% of the genes were differentially expressed in the mutant compared to the wild type strain at all time points. Out of those only 12% were known sporulation genes. As expected, the genes belonging to the regulon of the sporulation specific transcription factors (σ F , σ E , σ G , σ K ) were strongly down-regulated in the mutant. Inactivation of spoIIE also caused differential expression of genes involved in various cell processes at each time point. Moreover, at 23 h, genes involved in butanol formation and tolerance, as well as in cell motility, were up-regulated in the mutant. In contrast, several genes involved in cell wall composition, oxidative stress and amino acid transport were down-regulated. These results indicate an intricate interdependence of sporulation and stationary phase cellular events in C. beijerinckii.
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Affiliation(s)
- Mamou Diallo
- Wageningen Food and Biobased Research, Wageningen, Netherlands
- Laboratory of Microbiology, Wageningen University, Wageningen, Netherlands
| | - Nicolas Kint
- Laboratoire Pathogènese des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
| | - Marc Monot
- Biomics platform, C2RT, Institut Pasteur, Paris, France
| | - Florent Collas
- Wageningen Food and Biobased Research, Wageningen, Netherlands
| | - Isabelle Martin-Verstraete
- Laboratoire Pathogènese des Bactéries Anaérobies, Institut Pasteur, UMR CNRS 2001, Université de Paris, Paris, France
- Institut Universitaire de France, Paris, France
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University, Wageningen, Netherlands
| | - Servé W. M. Kengen
- Laboratory of Microbiology, Wageningen University, Wageningen, Netherlands
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18
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Isticato R, Lanzilli M, Petrillo C, Donadio G, Baccigalupi L, Ricca E. Bacillus subtilisbuilds structurally and functionally different spores in response to the temperature of growth. Environ Microbiol 2019; 22:170-182. [DOI: 10.1111/1462-2920.14835] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/16/2019] [Accepted: 10/17/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Rachele Isticato
- Department of BiologyFederico II University of Naples, Complesso Universitario di Monte Sant'Angelo, Via Cinthia 80126 Naples Italy
| | - Mariamichela Lanzilli
- Department of BiologyFederico II University of Naples, Complesso Universitario di Monte Sant'Angelo, Via Cinthia 80126 Naples Italy
| | - Claudia Petrillo
- Department of BiologyFederico II University of Naples, Complesso Universitario di Monte Sant'Angelo, Via Cinthia 80126 Naples Italy
| | - Giuliana Donadio
- Department of BiologyFederico II University of Naples, Complesso Universitario di Monte Sant'Angelo, Via Cinthia 80126 Naples Italy
| | - Loredana Baccigalupi
- Department of Molecular Medicine and Medical BiotechnologyFederico II University of Naples, Complesso Universitario di Monte Sant'Angelo, Via Cinthia 80126 Naples Italy
| | - Ezio Ricca
- Department of BiologyFederico II University of Naples, Complesso Universitario di Monte Sant'Angelo, Via Cinthia 80126 Naples Italy
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19
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Kumar M, Flint SH, Palmer J, Plieger PG, Waterland M. The effect of phosphate on the heat resistance of spores of dairy isolates of Geobacillus stearothermophilus. Int J Food Microbiol 2019; 309:108334. [PMID: 31520893 DOI: 10.1016/j.ijfoodmicro.2019.108334] [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] [Received: 12/07/2018] [Revised: 08/15/2019] [Accepted: 09/01/2019] [Indexed: 10/26/2022]
Abstract
In this study, we show that phosphate decreases the spore heat resistance by accelerating the rate of loss of cations from spores. Heat resistance of spores of Geobacillus stearothermophilus A1, D1, P3 and ATCC 12980 were determined in distilled water containing varying concentrations (0.1, 1 and 2% w/v) of di‑sodium phosphate. The average decimal reduction times (D value) for strains A1, D1, P3 and ATCC 12980 in distilled water were 5.8, 6.8, 5.7 and 9 min at 110 °C respectively. On the addition of 0.1, 1 and 2% w/v of di‑sodium phosphate, the average D110 values of all the strains in distilled water were lowered by 50, 61 and 70% respectively. Addition of 0.05% w/v of Na-EDTA to distilled water resulted in lowering of the average D110 value of all the strains by 55%. Heat resistance of spores of A1, D1, P3 and ATCC 12980 was found to be associated with the Dipicolinic Acid (DPA) content whose concentrations were 0.25, 0.30, 0.27 and 1.6 pg per spore respectively. Analysis by atomic absorption spectroscopy revealed that the phosphate present in the heating medium causes excess release of calcium from spores with 2% w/v phosphate being highly effective, thus confirming the chelating effect of phosphate. This study provides insight into the heat resistance and the increased heat sensitivity of spores of G. stearothermophilus A1, D1 and P3 in the presence of phosphate, which can be used in the design of Cleaning in Place (CIP) systems involving phosphate based cleaning agents to combat biofilms and spores in the dairy industry.
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Affiliation(s)
- M Kumar
- Massey Institute of Food Science and Technology, Massey University, Palmerston North 4442, New Zealand
| | - S H Flint
- Massey Institute of Food Science and Technology, Massey University, Palmerston North 4442, New Zealand.
| | - J Palmer
- Massey Institute of Food Science and Technology, Massey University, Palmerston North 4442, New Zealand
| | - P G Plieger
- School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - M Waterland
- School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
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20
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Microbiota of milk powders and the heat resistance and spoilage potential of aerobic spore-forming bacteria. Int Dairy J 2018. [DOI: 10.1016/j.idairyj.2018.06.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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21
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Malleck T, Daufouy G, André S, Broussolle V, Planchon S. Temperature impacts the sporulation capacities and spore resistance of Moorella thermoacetica. Food Microbiol 2018. [DOI: 10.1016/j.fm.2017.11.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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22
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Lee CW, Park SH, Lee SG, Park HH, Kim HJ, Park H, Park H, Lee JH. Crystal structure of dihydrodipicolinate reductase (PaDHDPR) from Paenisporosarcina sp. TG-14: structural basis for NADPH preference as a cofactor. Sci Rep 2018; 8:7936. [PMID: 29786696 PMCID: PMC5962572 DOI: 10.1038/s41598-018-26291-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 05/04/2018] [Indexed: 11/09/2022] Open
Abstract
Dihydrodipicolinate reductase (DHDPR) is a key enzyme in the diaminopimelate- and lysine-synthesis pathways that reduces DHDP to tetrahydrodipicolinate. Although DHDPR uses both NADPH and NADH as a cofactor, the structural basis for cofactor specificity and preference remains unclear. Here, we report that Paenisporosarcina sp. TG-14 PaDHDPR has a strong preference for NADPH over NADH, as determined by isothermal titration calorimetry and enzymatic activity assays. We determined the crystal structures of PaDHDPR alone, with its competitive inhibitor (dipicolinate), and the ternary complex of the enzyme with dipicolinate and NADPH, with results showing that only the ternary complex had a fully closed conformation and suggesting that binding of both substrate and nucleotide cofactor is required for enzymatic activity. Moreover, NADPH binding induced local conformational changes in the N-terminal long loop (residues 34–59) of PaDHDPR, as the His35 and Lys36 residues in this loop interacted with the 2′-phosphate group of NADPH, possibly accounting for the strong preference of PaDHDPR for NADPH. Mutation of these residues revealed reduced NADPH binding and enzymatic activity, confirming their importance in NADPH binding. These findings provide insight into the mechanism of action and cofactor selectivity of this important bacterial enzyme.
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Affiliation(s)
- Chang Woo Lee
- Unit of Polar Genomics, Korea Polar Research Institute, Incheon, 21990, Republic of Korea.,Department of Polar Sciences, University of Science and Technology, Incheon, 21990, Republic of Korea
| | - Sun-Ha Park
- Unit of Polar Genomics, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Sung Gu Lee
- Unit of Polar Genomics, Korea Polar Research Institute, Incheon, 21990, Republic of Korea.,Department of Polar Sciences, University of Science and Technology, Incheon, 21990, Republic of Korea
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, 84 Heukseok-ro, Dongjak, Seoul, 06974, Republic of Korea
| | - Hak Jun Kim
- Department of Chemistry, Pukyong National University, 45 Yongso-ro, Busan, 48513, Republic of Korea
| | - HaJeung Park
- X-Ray Core, TRI, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Hyun Park
- Unit of Polar Genomics, Korea Polar Research Institute, Incheon, 21990, Republic of Korea.,Department of Polar Sciences, University of Science and Technology, Incheon, 21990, Republic of Korea
| | - Jun Hyuck Lee
- Unit of Polar Genomics, Korea Polar Research Institute, Incheon, 21990, Republic of Korea. .,Department of Polar Sciences, University of Science and Technology, Incheon, 21990, Republic of Korea.
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23
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Zhang J, Zhou A, Liu Y, Zhao B, Luan Y, Wang S, Yue X, Li Z. Microbial network of the carbonate precipitation process induced by microbial consortia and the potential application to crack healing in concrete. Sci Rep 2017; 7:14600. [PMID: 29097756 PMCID: PMC5668378 DOI: 10.1038/s41598-017-15177-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 10/23/2017] [Indexed: 11/09/2022] Open
Abstract
Current studies have employed various pure-cultures for improving concrete durability based on microbially induced carbonate precipitation (MICP). However, there have been very few reports concerned with microbial consortia, which could perform more complex tasks and be more robust in their resistance to environmental fluctuations. In this study, we constructed three microbial consortia that are capable of MICP under aerobic (AE), anaerobic (AN) and facultative anaerobic (FA) conditions. The results showed that AE consortia showed more positive effects on inorganic carbon conversion than AN and FA consortia. Pyrosequencing analysis showed that clear distinctions appeared in the community structure between different microbial consortia systems. Further investigation on microbial community networks revealed that the species in the three microbial consortia built thorough energetic and metabolic interaction networks regarding MICP, nitrate-reduction, bacterial endospores and fermentation communities. Crack-healing experiments showed that the selected cracks of the three consortia-based concrete specimens were almost completely healed in 28 days, which was consistent with the studies using pure cultures. Although the economic advantage might not be clear yet, this study highlights the potential implementation of microbial consortia on crack healing in concrete.
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Affiliation(s)
- Jiaguang Zhang
- College of Architecture and Civil Engineering, Taiyuan University of Technology, Taiyuan, China
- Shanxi Construction Engineering Group Corporation, Taiyuan, China
| | - Aijuan Zhou
- College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, China.
| | - Yuanzhen Liu
- College of Architecture and Civil Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Bowei Zhao
- College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Yunbo Luan
- College of mechanics, Taiyuan University of Technology, Taiyuan, China
| | - Sufang Wang
- College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Xiuping Yue
- College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Zhu Li
- College of Architecture and Civil Engineering, Taiyuan University of Technology, Taiyuan, China.
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24
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Kochan TJ, Somers MJ, Kaiser AM, Shoshiev MS, Hagan AK, Hastie JL, Giordano NP, Smith AD, Schubert AM, Carlson PE, Hanna PC. Intestinal calcium and bile salts facilitate germination of Clostridium difficile spores. PLoS Pathog 2017; 13:e1006443. [PMID: 28704538 PMCID: PMC5509370 DOI: 10.1371/journal.ppat.1006443] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 06/03/2017] [Indexed: 12/26/2022] Open
Abstract
Clostridium difficile (C. difficile) is an anaerobic gram-positive pathogen that is the leading cause of nosocomial bacterial infection globally. C. difficile infection (CDI) typically occurs after ingestion of infectious spores by a patient that has been treated with broad-spectrum antibiotics. While CDI is a toxin-mediated disease, transmission and pathogenesis are dependent on the ability to produce viable spores. These spores must become metabolically active (germinate) in order to cause disease. C. difficile spore germination occurs when spores encounter bile salts and other co-germinants within the small intestine, however, the germination signaling cascade is unclear. Here we describe a signaling role for Ca2+ during C. difficile spore germination and provide direct evidence that intestinal Ca2+ coordinates with bile salts to stimulate germination. Endogenous Ca2+ (released from within the spore) and a putative AAA+ ATPase, encoded by Cd630_32980, are both essential for taurocholate-glycine induced germination in the absence of exogenous Ca2+. However, environmental Ca2+ replaces glycine as a co-germinant and circumvents the need for endogenous Ca2+ fluxes. Cd630_32980 is dispensable for colonization in a murine model of C. difficile infection and ex vivo germination in mouse ileal contents. Calcium-depletion of the ileal contents prevented mutant spore germination and reduced WT spore germination by 90%, indicating that Ca2+ present within the gastrointestinal tract plays a critical role in C. difficile germination, colonization, and pathogenesis. These data provide a biological mechanism that may explain why individuals with inefficient intestinal calcium absorption (e.g., vitamin D deficiency, proton pump inhibitor use) are more prone to CDI and suggest that modulating free intestinal calcium is a potential strategy to curb the incidence of CDI. The anaerobic, spore-forming bacterium Clostridium difficile (C. difficile) is a prominent pathogen in hospitals worldwide and the leading cause of nosocomial diarrhea. Numerous risk factors are associated with C. difficile infections (CDIs) including: antibiotics, advanced age, vitamin D deficiency, and proton pump inhibitors. Antibiotic use disrupts the intestinal microbiota allowing for C. difficile to colonize, however, why these other risk factors increase CDI incidence is unclear. Notably, deficient intestinal calcium absorption (i.e., increased calcium levels) is associated with these risk factors. In this work, we investigate the role of calcium in C. difficile spore germination. C. difficile spores are the infectious particles and they must become metabolically active (germinate) to cause disease. Here, we show that calcium is required for C. difficile germination, specifically activating the key step of cortex hydrolysis, and that this calcium can be derived from either within the spore or the environment. We also demonstrate that intestinal calcium is required for efficient spore germination in vivo, suggesting that intestinal concentrations of other co-germinants are insufficient to induce C. difficile germination. Collectively, these data provide a mechanism that explains the strong clinical correlations between increased intestinal calcium levels and risk of CDI.
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Affiliation(s)
- Travis J. Kochan
- University of Michigan Medical School, Department of Microbiology and Immunology. Ann Arbor, Michigan, United States of America
| | - Madeline J. Somers
- University of Michigan Medical School, Department of Microbiology and Immunology. Ann Arbor, Michigan, United States of America
| | - Alyssa M. Kaiser
- University of Michigan Medical School, Department of Microbiology and Immunology. Ann Arbor, Michigan, United States of America
| | - Michelle S. Shoshiev
- University of Michigan Medical School, Department of Microbiology and Immunology. Ann Arbor, Michigan, United States of America
| | - Ada K. Hagan
- University of Michigan Medical School, Department of Microbiology and Immunology. Ann Arbor, Michigan, United States of America
| | - Jessica L. Hastie
- Center for Biologics Evaluation and Research, US Food and Drug Administration. Silver Spring, Maryland, United States of America
| | - Nicole P. Giordano
- Center for Biologics Evaluation and Research, US Food and Drug Administration. Silver Spring, Maryland, United States of America
| | - Ashley D. Smith
- Center for Biologics Evaluation and Research, US Food and Drug Administration. Silver Spring, Maryland, United States of America
| | - Alyxandria M. Schubert
- Center for Biologics Evaluation and Research, US Food and Drug Administration. Silver Spring, Maryland, United States of America
| | - Paul E. Carlson
- Center for Biologics Evaluation and Research, US Food and Drug Administration. Silver Spring, Maryland, United States of America
| | - Philip C. Hanna
- University of Michigan Medical School, Department of Microbiology and Immunology. Ann Arbor, Michigan, United States of America
- * E-mail:
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