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Korza G, DePratti S, Fairchild D, Wicander J, Kanaan J, Shames H, Nichols FC, Cowan A, Brul S, Setlow P. Expression of the 2Duf protein in wild-type Bacillus subtilis spores stabilizes inner membrane proteins and increases spore resistance to wet heat and hydrogen peroxide. J Appl Microbiol 2023; 134:lxad040. [PMID: 36841229 PMCID: PMC10035073 DOI: 10.1093/jambio/lxad040] [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: 12/05/2022] [Revised: 02/09/2023] [Accepted: 02/24/2023] [Indexed: 02/27/2023]
Abstract
AIMS This work aimed to characterize spore inner membrane (IM) properties and the mechanism of spore killing by wet heat and H2O2 with spores overexpressing the 2Duf protein, which is naturally encoded from a transposon found only in some Bacillus strains with much higher spore resistance than wild-type spores. METHODS AND RESULTS Killing of Bacillus subtilis spores by wet heat or hydrogen peroxide (H2O2) was slower when 2Duf was present, and Ca-dipicolinic acid release was slower than killing. Viabilities on rich plates of wet heat- or H2O2 -treated spores +/- 2Duf were lower when NaCl was added, but higher with glucose. Addition of glucose but not Casamino acids addition increased treated spores' viability on minimal medium plates. Spores with 2Duf required higher heat activation for germination, and their germination was more wet-heat resistant than that of wild-type spores, processes that involve IM proteins. IM permeability and lipid mobility were lower in spores with 2Duf, although IM phospholipid composition was similar in spores +/- 2Duf. CONCLUSIONS These results and previous work suggests that wet heat and H2O2 kill spores by damaging an IM enzyme or enzymes involved in oxidative phosphorylation.
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Affiliation(s)
- George Korza
- Department of Molecular Biology and Biophysics, Farmington, CT 06030-3305, USA
| | - Sarah DePratti
- Department of Molecular Biology and Biophysics, Farmington, CT 06030-3305, USA
| | - Daniel Fairchild
- Department of Molecular Biology and Biophysics, Farmington, CT 06030-3305, USA
| | - James Wicander
- Department of Molecular Biology and Biophysics, Farmington, CT 06030-3305, USA
| | - Julia Kanaan
- Department of Molecular Biology and Biophysics, Farmington, CT 06030-3305, USA
| | - Hannah Shames
- Department of Molecular Biology and Biophysics, Farmington, CT 06030-3305, USA
| | - Frank C Nichols
- Division of Periodontology, UConn Health, Farmington, CT 06030-3305, USA
| | - Ann Cowan
- Department of Molecular Biology and Biophysics, Farmington, CT 06030-3305, USA
| | - Stanley Brul
- Molecular Biology & Microbial Food Safety, Swammerdam Institute for Life Science, University of Amsterdam, 1098XH Amsterdam, UK
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, Farmington, CT 06030-3305, USA
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What's new and notable in bacterial spore killing! World J Microbiol Biotechnol 2021; 37:144. [PMID: 34351499 PMCID: PMC8342367 DOI: 10.1007/s11274-021-03108-0] [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: 05/17/2021] [Accepted: 07/05/2021] [Indexed: 02/08/2023]
Abstract
Spores of many species of the orders Bacillales and Clostridiales can be vectors for food spoilage, human diseases and intoxications, and biological warfare. Many agents are used for spore killing, including moist heat in an autoclave, dry heat at elevated temperatures, UV radiation at 254 and more recently 222 and 400 nm, ionizing radiation of various types, high hydrostatic pressures and a host of chemical decontaminants. An alternative strategy is to trigger spore germination, as germinated spores are much easier to kill than the highly resistant dormant spores—the so called “germinate to eradicate” strategy. Factors important to consider in choosing methods for spore killing include the: (1) cost; (2) killing efficacy and kinetics; (3) ability to decontaminate large areas in buildings or outside; and (4) compatibility of killing regimens with the: (i) presence of people; (ii) food quality; (iii) presence of significant amounts of organic matter; and (iv) minimal damage to equipment in the decontamination zone. This review will summarize research on spore killing and point out some common flaws which can make results from spore killing research questionable.
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Balotf S, Wilson R, Tegg RS, Nichols DS, Wilson CR. Quantitative proteomics provides an insight into germination-related proteins in the obligate biotrophic plant pathogen Spongospora subterranea. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:521-532. [PMID: 33928759 DOI: 10.1111/1758-2229.12955] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 04/15/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
The soil-borne and obligate plant-associated nature of S. subterranea has hindered a detailed study of this pathogen and in particular, the regulatory pathways driving the germination of S. subterranea remain unknown. To better understand the mechanisms that control the transition from dormancy to germination, protein profiles between dormant and germination stimulant-treated resting spores were compared using label-free quantitative proteomics. Among the ~680 proteins identified 20 proteins were found to be differentially expressed during the germination of S. subterranea resting spores. Elongation factor Tu, histones (H2A and H15), proteasome and DJ-1_PfpI, involved in transcription and translation, were upregulated during the germination of resting spores. Downregulation of both actin and beta-tubulin proteins occurred in the germinating spores, indicating that the changes in the cell wall cytoskeleton may be necessary for the morphological changes during the germination of the resting spore in S. subterranea. Our findings provide new approaches for the study of these and similar recalcitrant micro-organisms provide the first insights into the basic protein components of S. subterranea spores. A better understanding of S. subterranea biology may lead to the development of novel approaches for the management of persistent soil inoculum.
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Affiliation(s)
- Sadegh Balotf
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, New Town, Tas., 7008, Australia
| | - Richard Wilson
- Central Science Laboratory, University of Tasmania, Hobart, Tas., 7001, Australia
| | - Robert S Tegg
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, New Town, Tas., 7008, Australia
| | - David S Nichols
- Central Science Laboratory, University of Tasmania, Hobart, Tas., 7001, Australia
| | - Calum R Wilson
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, New Town, Tas., 7008, Australia
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Delbrück AI, Zhang Y, Heydenreich R, Mathys A. Bacillus spore germination at moderate high pressure: A review on underlying mechanisms, influencing factors, and its comparison with nutrient germination. Compr Rev Food Sci Food Saf 2021; 20:4159-4181. [PMID: 34147040 DOI: 10.1111/1541-4337.12789] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 02/05/2023]
Abstract
Spore-forming bacteria are resistant to stress conditions owing to their ability to form highly resistant dormant spores. These spores can survive adverse environmental conditions in nature, as well as decontamination processes in the food and related industries. Bacterial spores may return to their vegetative state through a process called germination. As spore germination is critical for the loss of resistance, outgrowth, and development of pathogenicity and spoilage potential, the germination pathway has piqued the interest of the scientific community. The inhibition and induction of germination have critical applications in the food industry. Targeted germination can aid in decreasing the resistance of spores and allow the application of milder inactivation procedures. This germination-inactivation strategy allows better maintenance of important food quality attributes. Different stimuli are reported to trigger germination. Among those, isostatic high pressure (HP) has gained increasing attention due to its potential applications in industrial processes. However, pressure-mediated spore germination is extremely heterogeneous as some spores germinate rapidly, while others exhibit slow germination or do not undergo germination at all. The successful and safe implementation of the germination-inactivation strategy, however, depends on the germination of all spores. Therefore, there is a need to elucidate the mechanisms of HP-mediated germination. This work aimed to critically review the current state of knowledge on Bacillus spore germination at a moderate HP of 50-300 MPa. In this review, the germination mechanism, heterogeneity, and influencing factors have been outlined along with knowledge gaps.
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Affiliation(s)
- Alessia I Delbrück
- Sustainable Food Processing Laboratory, Institute of Food, Nutrition and Health, Department of Health Science and Technology, ETH Zürich, Zurich, Switzerland
| | - Yifan Zhang
- Sustainable Food Processing Laboratory, Institute of Food, Nutrition and Health, Department of Health Science and Technology, ETH Zürich, Zurich, Switzerland
| | - Rosa Heydenreich
- Sustainable Food Processing Laboratory, Institute of Food, Nutrition and Health, Department of Health Science and Technology, ETH Zürich, Zurich, Switzerland
| | - Alexander Mathys
- Sustainable Food Processing Laboratory, Institute of Food, Nutrition and Health, Department of Health Science and Technology, ETH Zürich, Zurich, Switzerland
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Luo Y, Korza G, DeMarco AM, Kuipers OP, Li YQ, Setlow P. Properties of spores of Bacillus subtilis with or without a transposon that decreases spore germination and increases spore wet heat resistance. J Appl Microbiol 2021; 131:2918-2928. [PMID: 34042237 DOI: 10.1111/jam.15163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 03/14/2021] [Accepted: 05/03/2021] [Indexed: 01/01/2023]
Abstract
AIMS This work aimed to determine how genes on transposon Tn1546 slow Bacillus subtilis spore germination and increase wet heat resistance, and to clarify the transposon's 3 gene spoVA operon's role in spore properties, since the seven wild-type SpoVA proteins form a channel transporting Ca2+ -dipicolinic acid (DPA) in spore formation and germination. METHODS AND RESULTS Deletion of the wild-type spoVA operon from a strain with Tn1546 gave spores with slightly reduced wet heat resistance but some large decreases in germination rate. Spore water content and CaDPA analyses found no significant differences in contents of either component in spores with different Tn1546 components or lacking the wild-type spoVA operon. CONCLUSIONS This work indicates that the SpoVA channel encoded by Tn1546 functions like the wild-type SpoVA channel in CaDPA uptake into developing spores, but not as well in germination. The essentially identical CaDPA and water contents of spores with and without Tn1546 indicate that low core water content does not cause elevated wet heat resistance of spores with Tn1546. SIGNIFICANCE AND IMPACT OF THE STUDY Since wet heat resistance of spores of Bacillus species poses problems in the food industry, understanding mechanisms of spores' wet heat resistance is of significant applied interest.
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Affiliation(s)
- Y Luo
- Department of Physics, East Carolina University, Greenville, NC, USA.,Laboratory for Biomedical Photonics & Engineering, Life Sciences Institute, Guangxi Medical University, Nanning, Guangxi, P.R. China
| | - G Korza
- Department of Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - A M DeMarco
- Department of Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - O P Kuipers
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
| | - Y-Q Li
- Department of Physics, East Carolina University, Greenville, NC, USA.,School of Electronic Engineering, Dongguan University of Technology, Dongguan, Guangdong, P.R. China
| | - P Setlow
- Department of Molecular Genetics, University of Groningen, Groningen, The Netherlands
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Xing Y, Harper WF. Bacillus spore awakening: recent discoveries and technological developments. Curr Opin Biotechnol 2020; 64:110-115. [DOI: 10.1016/j.copbio.2019.12.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 12/21/2019] [Accepted: 12/23/2019] [Indexed: 12/25/2022]
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The Copy Number of the spoVA 2mob Operon Determines Pressure Resistance of Bacillus Endospores. Appl Environ Microbiol 2019; 85:AEM.01596-19. [PMID: 31375487 DOI: 10.1128/aem.01596-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 07/27/2019] [Indexed: 12/27/2022] Open
Abstract
The spoVA 2mob operon confers heat resistance to Bacillus spp., and the resistance correlates to the copy number of the operon. Bacillus endospores also exhibit a strong variation in resistance to pressure, but the underlying mechanisms of endospore resistance to pressure are not fully understood. We determined the effects of multiple spoVA 2mob operons on high-pressure resistance in Bacillus endospores. The copy numbers of the spoVA 2mob operon in 17 strains of Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus cereus, Bacillus velezensis, and Bacillus pumilus were determined via droplet digital PCR (ddPCR) and genome sequencing. These strains contained between 0 and 3 copies of the spoVA 2mob operon; the quantification of the gene copy number by ddPCR was as accurate as whole-genome sequencing. We further tested the pressure resistance of 17 Bacillus endospores at 600 MPa and 80°C. Strains with one or no spoVA 2mob operon had significantly lower pressure resistance than strains with two or three copies of the operons (P < 0.001), indicating that redundant spoVA 2mob operons in Bacillus contributed to higher pressure resistance of endospores. The copy number of the spoVA 2mob operon was not related to the dipicolinic acid (DPA) content of endospores. Overall, the copy number of the spoVA 2mob operon contributes to pressure resistance of Bacillus endospores. This improves our understanding of the pressure resistance mechanisms in Bacillus spp. and may inform the development of high-pressure sterilization in food processing.IMPORTANCE Bacillus spp. are considered pressure-resistant microorganisms, but the resistance mechanisms remain unknown. The spoVA 2mob operon is a mobile genetic element, and it can transfer to pathogenic or spoilage organisms by horizontal gene transfer. Results in this study indicate that multiple copies of the spoVA 2mob operon mediate high-pressure resistance of Bacillus endospores, and it might contribute to the identification of the source of pressure-resistant pathogens and spoilage organisms that may contaminate the food supply. The droplet digital PCR (ddPCR) system is well suited for analysis in some human diseases due to its high efficiency and capability to provide high precision; however, no relevant studies in food microbiology have been reported so far. This study demonstrates a novel application of ddPCR in food microbiology.
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Daqu Fermentation Selects for Heat-Resistant Enterobacteriaceae and Bacilli. Appl Environ Microbiol 2018; 84:AEM.01483-18. [PMID: 30120119 DOI: 10.1128/aem.01483-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 08/15/2018] [Indexed: 11/20/2022] Open
Abstract
Daqu is a spontaneous solid-state cereal fermentation used as saccharification and starter culture in Chinese vinegar and liquor production. The evolution of microbiota in this spontaneous fermentation is controlled by the temperature profile, which reaches temperatures from 50 to 65°C for several days. Despite these high temperatures, mesophilic Enterobacteriaceae (including Cronobacter) and bacilli are present throughout Daqu fermentation. This study aimed to determine whether Daqu spontaneous solid-state fermentation selects for heat-resistant variants of these organisms. Heat resistance in Enterobacteriaceae is mediated by the locus of heat resistance (LHR). One LHR-positive strain of Kosakonia cowanii was identified in Daqu, and it exhibited higher heat resistance than the LHR-negative K. cowanii isolated from malted oats. Heat resistance in Bacillus endospores is mediated by the spoVA 2mob operon. Out of 10 Daqu isolates of the species Bacillus licheniformis, Brevibacillus parabrevis, Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus velezensis, 5 did not contain spoVA 2mob, 3 contained one copy, and 2 contained two copies. The presence and copy number of the spoVA 2mob operon increased the resistance of spores to treatment with 110°C. To confirm the selection of LHR- and spoVA 2mob-positive strains during Daqu fermentation, the copy numbers of these genetic elements in Daqu samples were quantified by quantitative PCR (qPCR). The abundance of LHR and the spoVA 2mob operon in community DNA relative to that of total bacterial 16S rRNA genes increased 3-fold and 5-fold, respectively, during processing. In conclusion, culture-dependent and culture-independent analyses suggest that Daqu fermentation selects for heat-resistant Enterobacteriaceae and bacilli.IMPORTANCE Daqu fermentations select for mobile genetic elements conferring heat resistance in Enterobacteriaceae and bacilli. The locus of heat resistance (LHR), a genomic island conferring heat resistance in Enterobacteriaceae, and the spoVA 2mob operon, conferring heat resistance on bacterial endospores, were enriched 3- to 5-fold during Daqu fermentation and maturation. It is therefore remarkable that the LHR and the spoVA 2mob operon are accumulated in the same food fermentation. The presence of heat-resistant Kosakonia spp. and Bacillus spp. in Daqu is not of concern for food safety; however, both genomic islands are mobile and transferable to pathogenic bacteria or toxin-producing bacteria by horizontal gene transfer. The identification of the LHR and the spoVA 2mob operon as indicators of fitness of Enterobacteriaceae and bacilli in Daqu fermentation provides insights into environmental sources of heat-resistant organisms that may contaminate the food supply.
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Abstract
Dormant Bacillales and Clostridiales spores begin to grow when small molecules (germinants) trigger germination, potentially leading to food spoilage or disease. Germination-specific proteins sense germinants, transport small molecules, and hydrolyze specific bonds in cortex peptidoglycan and specific proteins. Major events in germination include (a) germinant sensing; (b) commitment to germinate; (c) release of spores' depot of dipicolinic acid (DPA); (d) hydrolysis of spores' peptidoglycan cortex; and (e) spore core swelling and water uptake, cell wall peptidoglycan remodeling, and restoration of core protein and inner spore membrane lipid mobility. Germination is similar between Bacillales and Clostridiales, but some species differ in how germinants are sensed and how cortex hydrolysis and DPA release are triggered. Despite detailed knowledge of the proteins and signal transduction pathways involved in germination, precisely what some germination proteins do and how they do it remain unclear.
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Affiliation(s)
- Peter Setlow
- Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut 06030-3305;
| | - Shiwei Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China;
| | - Yong-Qing Li
- Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353;
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Spore Heat Activation Requirements and Germination Responses Correlate with Sequences of Germinant Receptors and with the Presence of a Specific spoVA2mob Operon in Foodborne Strains of Bacillus subtilis. Appl Environ Microbiol 2017; 83:AEM.03122-16. [PMID: 28130296 DOI: 10.1128/aem.03122-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 01/21/2017] [Indexed: 01/19/2023] Open
Abstract
Spore heat resistance, germination, and outgrowth are problematic bacterial properties compromising food safety and quality. Large interstrain variation in these properties makes prediction and control of spore behavior challenging. High-level heat resistance and slow germination of spores of some natural Bacillus subtilis isolates, encountered in foods, have been attributed to the occurrence of the spoVA2mob operon carried on the Tn1546 transposon. In this study, we further investigate the correlation between the presence of this operon in high-level-heat-resistant spores and their germination efficiencies before and after exposure to various sublethal heat treatments (heat activation, or HA), which are known to significantly improve spore responses to nutrient germinants. We show that high-level-heat-resistant spores harboring spoVA2mob required higher HA temperatures for efficient germination than spores lacking spoVA2mob The optimal spore HA requirements additionally depended on the nutrients used to trigger germination, l-alanine (l-Ala), or a mixture of l-asparagine, d-glucose, d-fructose, and K+ (AGFK). The distinct HA requirements of these two spore germination pathways are likely related to differences in properties of specific germinant receptors. Moreover, spores that germinated inefficiently in AGFK contained specific changes in sequences of the GerB and GerK germinant receptors, which are involved in this germination response. In contrast, no relation was found between transcription levels of main germination genes and spore germination phenotypes. The findings presented in this study have great implications for practices in the food industry, where heat treatments are commonly used to inactivate pathogenic and spoilage microbes, including bacterial spore formers.IMPORTANCE This study describes a strong variation in spore germination capacities and requirements for a heat activation treatment, i.e., an exposure to sublethal heat that increases spore responsiveness to nutrient germination triggers, among 17 strains of B. subtilis, including 9 isolates from spoiled food products. Spores of industrial foodborne isolates exhibited, on average, less efficient and slower germination responses and required more severe heat activation than spores from other sources. High heat activation requirements and inefficient, slow germination correlated with elevated resistance of spores to heat and with specific genetic features, indicating a common genetic basis of these three phenotypic traits. Clearly, interstrain variation and numerous factors that shape spore germination behavior challenge standardization of methods to recover highly heat-resistant spores from the environment and have an impact on the efficacy of preservation techniques used by the food industry to control spores.
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Johnson CL, Moir A. Proteins YlaJ and YhcN contribute to the efficiency of spore germination in Bacillus subtilis. FEMS Microbiol Lett 2017; 364:3045907. [DOI: 10.1093/femsle/fnx047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 02/22/2017] [Indexed: 11/14/2022] Open
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Warda AK, Xiao Y, Boekhorst J, Wells-Bennik MHJ, Nierop Groot MN, Abee T. Analysis of Germination Capacity and Germinant Receptor (Sub)clusters of Genome-Sequenced Bacillus cereus Environmental Isolates and Model Strains. Appl Environ Microbiol 2017; 83:e02490-16. [PMID: 27881417 PMCID: PMC5288832 DOI: 10.1128/aem.02490-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 11/17/2016] [Indexed: 12/28/2022] Open
Abstract
Spore germination of 17 Bacillus cereus food isolates and reference strains was evaluated using flow cytometry analysis in combination with fluorescent staining at a single-spore level. This approach allowed for rapid collection of germination data under more than 20 conditions, including heat activation of spores, germination in complex media (brain heart infusion [BHI] and tryptone soy broth [TSB]), and exposure to saturating concentrations of single amino acids and the combination of alanine and inosine. Whole-genome sequence comparison revealed a total of 11 clusters of operons encoding germinant receptors (GRs): GerK, GerI, and GerL were present in all strains, whereas GerR, GerS, GerG, GerQ, GerX, GerF, GerW, and GerZ (sub)clusters showed a more diverse presence/absence in different strains. The spores of tested strains displayed high diversity with regard to their sensitivity and responsiveness to selected germinants and heat activation. The two laboratory strains, B. cereus ATCC 14579 and ATCC 10987, and 11 food isolates showed a good germination response under a range of conditions, whereas four other strains (B. cereus B4085, B4086, B4116, and B4153) belonging to phylogenetic group IIIA showed a very weak germination response even in BHI and TSB media. Germination responses could not be linked to specific (combinations of) GRs, but it was noted that the four group IIIA strains contained pseudogenes or variants of subunit C in their gerL cluster. Additionally, two of those strains (B4086 and B4153) carried pseudogenes in the gerK and gerRI (sub)clusters that possibly affected the functionality of these GRs. IMPORTANCE Germination of bacterial spores is a critical step before vegetative growth can resume. Food products may contain nutrient germinants that trigger germination and outgrowth of Bacillus species spores, possibly leading to food spoilage or foodborne illness. Prediction of spore germination behavior is, however, very challenging, especially for spores of natural isolates that tend to show more diverse germination responses than laboratory strains. The approach used has provided information on the genetic diversity in GRs and corresponding subclusters encoded by B. cereus strains, as well as their germination behavior and possible associations with GRs, and it provides a basis for further extension of knowledge on the role of GRs in B. cereus (group member) ecology and transmission to the host.
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Affiliation(s)
- Alicja K Warda
- TI Food and Nutrition, Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
- Wageningen Food and Biobased Research, Wageningen, The Netherlands
| | - Yinghua Xiao
- TI Food and Nutrition, Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Jos Boekhorst
- TI Food and Nutrition, Wageningen, The Netherlands
- NIZO Food Research B.V., Ede, The Netherlands
| | - Marjon H J Wells-Bennik
- TI Food and Nutrition, Wageningen, The Netherlands
- NIZO Food Research B.V., Ede, The Netherlands
| | - Masja N Nierop Groot
- TI Food and Nutrition, Wageningen, The Netherlands
- Wageningen Food and Biobased Research, Wageningen, The Netherlands
| | - Tjakko Abee
- TI Food and Nutrition, Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
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Prospects for improved control of dairy-relevant sporeformers using -omics technologies. Curr Opin Food Sci 2016. [DOI: 10.1016/j.cofs.2016.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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