1
|
Trunet C, Vischer N, Coroller L, Brul S. Germination and outgrowth of Bacillus mycoides KBAB4 spores are impacted by environmental pH, quantitatively analyzed at single cell level with sporetracker. Food Microbiol 2024; 121:104509. [PMID: 38637073 DOI: 10.1016/j.fm.2024.104509] [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: 11/22/2023] [Revised: 02/06/2024] [Accepted: 02/24/2024] [Indexed: 04/20/2024]
Abstract
Quantifying spore germination and outgrowth heterogeneity is challenging. Single cell level analysis should provide supplementary knowledge regarding the impact of unfavorable conditions on germination and outgrowth dynamics. This work aimed to quantify the impact of pH on spore germination and outgrowth, investigating the behavior of individual spore crops, produced under optimal and suboptimal conditions. Bacillus mycoides (formerly B. weihenstephanensis) KBAB4 spores, produced at pH 7.4 and at pH 5.5 were incubated at different pH values, from pH 5.2 to 7.4. The spores were monitored by microscopy live imaging, in controlled conditions, at 30 °C. The images were analyzed using SporeTracker, to determine the state of single cells. The impact of pH on germination and outgrowth times and rates was estimated and the correlation between these parameters was quantified. The correlation between germination and outgrowth times was significantly higher at low pH. These results suggest that an environmental pressure highlights the heterogeneity of spore germination and outgrowth within a spore population. Results were consistent with previous observations at population level, now confirmed and extended to single cell level. Therefore, single cell level analyses can be used to quantify the heterogeneity of spore populations, which is of interest in order to control the development of spore-forming bacteria, responsible for food safety issues.
Collapse
Affiliation(s)
- C Trunet
- Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Écologie Microbienne, F-29000, Quimper, France.
| | - N Vischer
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands
| | - L Coroller
- Univ Brest, INRAE, Laboratoire Universitaire de Biodiversité et Écologie Microbienne, F-29000, Quimper, France
| | - S Brul
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Wang Y, Yuan H, Zhao X, Zhang P, Wang G, Gao F. Compressive Raman imaging by combining scattering-projection interleaving with context-aware excitation. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2024; 16:583-588. [PMID: 38189485 DOI: 10.1039/d3ay02231e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Exciting an object with a laser-focus array and randomly interleaving its scattering projection has been proved to be an effective strategy for speeding up Raman imaging. The so-called scattering interleaved Raman imaging (SIRI) method allows Raman hyperspectral imaging with a single snapshot and exhibits excellent reconstruction fidelity and signal-to-noise ratios (SNRs). Here, we show that the performance of SIRI is significantly improved when combined with context-aware excitation. The experiments on micro-plastics demonstrate that the restriction of Raman excitation within a smaller region of interest as guided by bright-field microscopy improves the signal intensity and the SNR, and it is surprising that the spectral resolution is also significantly improved. The context-aware SIRI method is successfully used for imaging of lipid-producing yeast cells, suggesting that it is a promising analytical tool for studying live cells or tissues.
Collapse
Affiliation(s)
- Yakun Wang
- School of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin, 300072, China.
| | - Hang Yuan
- School of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin, 300072, China.
| | - Xuan Zhao
- School of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin, 300072, China.
| | - Pengfei Zhang
- School of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin, 300072, China.
| | - Guiwen Wang
- Guangxi Academy of Sciences, 98 Daling Road, Nanning, Guangxi 530007, China.
| | - Feng Gao
- School of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin, 300072, China.
| |
Collapse
|
4
|
Ribis JW, Melo L, Shrestha S, Giacalone D, Rodriguez EE, Shen A, Rohlfing A. Single-spore germination analyses reveal that calcium released during Clostridioides difficile germination functions in a feedforward loop. mSphere 2023; 8:e0000523. [PMID: 37338207 PMCID: PMC10449524 DOI: 10.1128/msphere.00005-23] [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: 01/18/2023] [Accepted: 04/21/2023] [Indexed: 06/21/2023] Open
Abstract
Clostridioides difficile infections begin when its metabolically dormant spores germinate in response to sensing bile acid germinants alongside amino acid and divalent cation co-germinants in the small intestine. While bile acid germinants are essential for C. difficile spore germination, it is currently unclear whether both co-germinant signals are required. One model proposes that divalent cations, particularly Ca2+, are essential for inducing germination, while another proposes that either co-germinant class can induce germination. The former model is based on the finding that spores defective in releasing large stores of internal Ca2+ in the form of calcium dipicolinic acid (CaDPA) cannot germinate when germination is induced with bile acid germinant and amino acid co-germinant alone. However, since the reduced optical density of CaDPA-less spores makes it difficult to accurately measure their germination, we developed a novel automated, time-lapse microscopy-based germination assay to analyze CaDPA mutant germination at the single-spore level. Using this assay, we found that CaDPA mutant spores germinate in the presence of amino acid co-germinant and bile acid germinant. Higher levels of amino acid co-germinants are nevertheless required to induce CaDPA mutant spores to germinate relative to WT spores because CaDPA released by WT spores during germination can function in a feedforward loop to potentiate the germination of other spores within the population. Collectively, these data indicate that Ca2+ is not essential for inducing C. difficile spore germination because amino acid and Ca2+ co-germinant signals are sensed by parallel signaling pathways. IMPORTANCE Clostridioides difficile spore germination is essential for this major nosocomial pathogen to initiate infection. C. difficile spores germinate in response to sensing bile acid germinant signals alongside co-germinant signals. There are two classes of co-germinant signals: Ca2+ and amino acids. Prior work suggested that Ca2+ is essential for C. difficile spore germination based on bulk population analyses of germinating CaDPA mutant spores. Since these assays rely on optical density to measure spore germination and the optical density of CaDPA mutant spores is reduced relative to WT spores, this bulk assay is limited in its capacity to analyze germination. To overcome this limitation, we developed an automated image analysis pipeline to monitor C. difficile spore germination using time-lapse microscopy. With this analysis pipeline, we demonstrate that, although Ca2+ is dispensable for inducing C. difficile spore germination, CaDPA can function in a feedforward loop to potentiate the germination of neighboring spores.
Collapse
Affiliation(s)
- John W. Ribis
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Luana Melo
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Shailab Shrestha
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - David Giacalone
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | | | - Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Amy Rohlfing
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
- Tufts University, Boston, Massachusetts, USA
| |
Collapse
|
5
|
Lyu F, Zhang T, Gui M, Wang Y, Zhao L, Wu X, Rao L, Liao X. The underlying mechanism of bacterial spore germination: An update review. Compr Rev Food Sci Food Saf 2023; 22:2728-2746. [PMID: 37125461 DOI: 10.1111/1541-4337.13160] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/22/2023] [Accepted: 04/01/2023] [Indexed: 05/02/2023]
Abstract
Bacterial spores are highly resilient and universally present on earth and can irreversibly enter the food chain to cause food spoilage or foodborne illness once revived to resume vegetative growth. Traditionally, extensive thermal processing has been employed to efficiently kill spores; however, the relatively high thermal load adversely affects food quality attributes. In recent years, the germination-inactivation strategy has been developed to mildly kill spores based on the circumstance that germination can decrease spore-resilient properties. However, the failure to induce all spores to geminate, mainly owing to the heterogeneous germination behavior of spores, hampers the success of applying this strategy in the food industry. Undoubtedly, elucidating the detailed germination pathway and underlying mechanism can fill the gap in our understanding of germination heterogeneity, thereby facilitating the development of full-scale germination regimes to mildly kill spores. In this review, we comprehensively discuss the mechanisms of spore germination of Bacillus and Clostridium species, and update the molecular basis of the early germination events, for example, the activation of germination receptors, ion release, Ca-DPA release, and molecular events, combined with the latest research evidence. Moreover, high hydrostatic pressure (HHP), an advanced non-thermal food processing technology, can also trigger spore germination, providing a basis for the application of a germination-inactivation strategy in HHP processing. Here, we also summarize the diverse germination behaviors and mechanisms of spores of Bacillus and Clostridium species under HHP, with the aim of facilitating HHP as a mild processing technology with possible applications in food sterilization. Practical Application: This work provides fundamental basis for developing efficient killing strategies of bacterial spores in food industry.
Collapse
Affiliation(s)
- Fengzhi Lyu
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruit and Vegetable Processing of Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory for Food Non-Thermal Processing, China Agricultural University, Beijing, China
| | - Tianyu Zhang
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruit and Vegetable Processing of Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory for Food Non-Thermal Processing, China Agricultural University, Beijing, China
| | - Meng Gui
- Fisheries Science Institute Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Yongtao Wang
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruit and Vegetable Processing of Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory for Food Non-Thermal Processing, China Agricultural University, Beijing, China
| | - Liang Zhao
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruit and Vegetable Processing of Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory for Food Non-Thermal Processing, China Agricultural University, Beijing, China
| | - Xiaomeng Wu
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruit and Vegetable Processing of Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory for Food Non-Thermal Processing, China Agricultural University, Beijing, China
| | - Lei Rao
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruit and Vegetable Processing of Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory for Food Non-Thermal Processing, China Agricultural University, Beijing, China
| | - Xiaojun Liao
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruit and Vegetable Processing of Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory for Food Non-Thermal Processing, China Agricultural University, Beijing, China
| |
Collapse
|
6
|
Qiu X, Chang J, Jin Y, Wu WJ. Pulsed Electric Field Treatments with Nonlethal Field Strength Alter the Properties of Bacterial Spores. J Food Prot 2022; 85:1053-1060. [PMID: 35512130 DOI: 10.4315/jfp-21-447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 05/02/2022] [Indexed: 11/11/2022]
Abstract
ABSTRACT Pulsed electric field (PEF) treatment, an alternative to thermal processing in the food industry, is insufficient to inactivate bacterial spores. Although spores that have been treated in this manner remain alive, specific understanding of their physiological properties is limited. The purpose of this study is to describe the morphology, viability, and germination behavior of Bacillus atrophaeus spores treated with PEF. Our findings indicate that nonlethal PEF treatment results in spore deformation, dipicolinic acid (DPA) leakage, and a shorter and more uniform germination lag time (\(\def\upalpha{\unicode[Times]{x3B1}}\)\(\def\upbeta{\unicode[Times]{x3B2}}\)\(\def\upgamma{\unicode[Times]{x3B3}}\)\(\def\updelta{\unicode[Times]{x3B4}}\)\(\def\upvarepsilon{\unicode[Times]{x3B5}}\)\(\def\upzeta{\unicode[Times]{x3B6}}\)\(\def\upeta{\unicode[Times]{x3B7}}\)\(\def\uptheta{\unicode[Times]{x3B8}}\)\(\def\upiota{\unicode[Times]{x3B9}}\)\(\def\upkappa{\unicode[Times]{x3BA}}\)\(\def\uplambda{\unicode[Times]{x3BB}}\)\(\def\upmu{\unicode[Times]{x3BC}}\)\(\def\upnu{\unicode[Times]{x3BD}}\)\(\def\upxi{\unicode[Times]{x3BE}}\)\(\def\upomicron{\unicode[Times]{x3BF}}\)\(\def\uppi{\unicode[Times]{x3C0}}\)\(\def\uprho{\unicode[Times]{x3C1}}\)\(\def\upsigma{\unicode[Times]{x3C3}}\)\(\def\uptau{\unicode[Times]{x3C4}}\)\(\def\upupsilon{\unicode[Times]{x3C5}}\)\(\def\upphi{\unicode[Times]{x3C6}}\)\(\def\upchi{\unicode[Times]{x3C7}}\)\(\def\uppsy{\unicode[Times]{x3C8}}\)\(\def\upomega{\unicode[Times]{x3C9}}\)\(\def\bialpha{\boldsymbol{\alpha}}\)\(\def\bibeta{\boldsymbol{\beta}}\)\(\def\bigamma{\boldsymbol{\gamma}}\)\(\def\bidelta{\boldsymbol{\delta}}\)\(\def\bivarepsilon{\boldsymbol{\varepsilon}}\)\(\def\bizeta{\boldsymbol{\zeta}}\)\(\def\bieta{\boldsymbol{\eta}}\)\(\def\bitheta{\boldsymbol{\theta}}\)\(\def\biiota{\\boldsymbol{\iota}}\)\(\def\bikappa{\boldsymbol{\kappa}}\)\(\def\bilambda{\boldsymbol{\lambda}}\)\(\def\\bimu{\boldsymbol{\mu}}\)\(\def\binu{\boldsymbol{\nu}}\)\(\def\bixi{\boldsymbol{\xi}}\)\(\def\biomicron{\boldsymbol{\micron}}\)\(\def\bipi{\boldsymbol{\pi}}\)\(\def\birho{\boldsymbol{\rho}}\)\(\def\bisigma{\boldsymbol{\sigma}}\)\(\def\bitau{\boldsymbol{\\tau}}\)\(\def\biupsilon{\boldsymbol{\upsilon}}\)\(\def\biphi{\boldsymbol{\phi}}\)\(\def\bichi{\boldsymbol{\chi}}\)\(\def\bipsy{\boldsymbol{\psy}}\)\(\def\biomega{\boldsymbol{\omega}}\)\(\def\bupalpha{\bf{\alpha}}\)\(\def\bupbeta{\bf{\beta}}\)\(\def\bupgamma{\bf{\gamma}}\)\(\def\bupdelta{\bf{\delta}}\)\(\def\bupvarepsilon{\bf{\varepsilon}}\)\(\def\bupzeta{\bf{\zeta}}\)\(\def\bupeta{\bf{\eta}}\)\(\def\buptheta{\bf{\theta}}\)\(\def\bupiota{\bf{\iota}}\)\(\def\bupkappa{\bf{\kappa}}\)\(\def\\buplambda{\bf{\lambda}}\)\(\def\bupmu{\bf{\mu}}\)\(\def\bupnu{\bf{\nu}}\)\(\def\bupxi{\bf{\xi}}\)\(\def\bupomicron{\bf{\micron}}\)\(\def\buppi{\bf{\pi}}\)\(\def\buprho{\bf{\rho}}\)\(\def\bupsigma{\bf{\sigma}}\)\(\def\buptau{\bf{\tau}}\)\(\def\bupupsilon{\bf{\upsilon}}\)\(\def\bupphi{\bf{\phi}}\)\(\def\bupchi{\bf{\chi}}\)\(\def\buppsy{\bf{\psy}}\)\(\def\bupomega{\bf{\omega}}\)\(\def\bGamma{\bf{\Gamma}}\)\(\def\bDelta{\bf{\Delta}}\)\(\def\bTheta{\bf{\Theta}}\)\(\def\bLambda{\bf{\Lambda}}\)\(\def\bXi{\bf{\Xi}}\)\(\def\bPi{\bf{\Pi}}\)\(\def\bSigma{\bf{\Sigma}}\)\(\def\bPhi{\bf{\Phi}}\)\(\def\bPsi{\bf{\Psi}}\)\(\def\bOmega{\bf{\Omega}}\)\({T_{{\rm{lag}}}}\)), but that there is no change in release duration (\(\Delta {T_{{\rm{release}}}}\)), germination ratio, or viability. Based on our findings, we conclude that an intact morphologic state and DPA content are not prerequisites for germination and full viability and that, in contrast to nutrient-induced germination in which initially slowly released DPA triggers subsequent germination events, leaked DPA during PEF treatment does not. Spores that have been subjected to this procedure remain dormant and preserve their full germinability. We found that PEF-treated spores respond to germinants more quickly and with less heterogeneity, possibly because the tiny cracks formed on the spore surface facilitate the germinants' access to the germination receptors situated on the spore's inner membrane. The consensus view that nonlethal PEF has less impact on spores that are still capable of forming CFUs under proper conditions is one-sided. This research advances our understanding of how spores behave following nonlethal PEF treatment and gives information on the topics of nosocomial sterilization, food safety, and public health. HIGHLIGHTS
Collapse
Affiliation(s)
- Xing Qiu
- Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong 999077, People's Republic of China
| | - Jinhui Chang
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong 999077, People's Republic of China
| | - Yong Jin
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong 999077, People's Republic of China.,Faculty of Business, The Hong Kong Polytechnic University, Hong Kong 999077, People's Republic of China
| | - Wen Jie Wu
- Department of Radiation Physics, The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, People's Republic of China.,Zhejiang Key Laboratory of Radiation Oncology, Hangzhou, Zhejiang 310022, People's Republic of China
| |
Collapse
|
7
|
Grosso RA, Walther AR, Brunbech E, Sørensen A, Schebye B, Olsen KE, Qu H, Hedegaard MAB, Arnspang EC. Detection of low numbers of bacterial cells in a pharmaceutical drug product using Raman spectroscopy and PLS-DA multivariate analysis. Analyst 2022; 147:3593-3603. [DOI: 10.1039/d2an00683a] [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]
Abstract
Fast and non-invasive approach to detect drug product (DP) samples with low numbers of bacteria within the primary packaging. The method combines Raman spectroscopy and partial least squared discriminant analysis (RS-PLS-DA).
Collapse
Affiliation(s)
- R. A. Grosso
- Department of Green Technology, SDU- Biotechnology, University of Southern Denmark, Odense, Denmark
- Product Supply Injectable Finished Products, Microbial Competence Centre, Novo Nordisk A/S, Copenhagen, Denmark
| | - A. R. Walther
- Department of Green Technology, SDU- Biotechnology, University of Southern Denmark, Odense, Denmark
| | - E. Brunbech
- Product Supply Injectable Finished Products, Microbial Competence Centre, Novo Nordisk A/S, Copenhagen, Denmark
| | - A. Sørensen
- Product Supply Injectable Finished Products, Microbial Competence Centre, Novo Nordisk A/S, Copenhagen, Denmark
| | - B. Schebye
- Product Supply Injectable Finished Products, Technology Innovation, Novo Nordisk A/S, Copenhagen, Denmark
| | - K. E. Olsen
- Product Supply Injectable Finished Products, Microbial Competence Centre, Novo Nordisk A/S, Copenhagen, Denmark
| | - H. Qu
- Department of Green Technology, SDU- Biotechnology, University of Southern Denmark, Odense, Denmark
| | - M. A. B. Hedegaard
- Department of Green Technology, SDU- Biotechnology, University of Southern Denmark, Odense, Denmark
| | - E. C. Arnspang
- Department of Green Technology, SDU- Biotechnology, University of Southern Denmark, Odense, Denmark
| |
Collapse
|
8
|
AlMasoud N, Muhamadali H, Chisanga M, AlRabiah H, Lima CA, Goodacre R. Discrimination of bacteria using whole organism fingerprinting: the utility of modern physicochemical techniques for bacterial typing. Analyst 2021; 146:770-788. [DOI: 10.1039/d0an01482f] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review compares and contrasts MALDI-MS, FT-IR spectroscopy and Raman spectroscopy for whole organism fingerprinting and bacterial typing.
Collapse
Affiliation(s)
- Najla AlMasoud
- Department of Chemistry
- College of Science
- Princess Nourah bint Abdulrahman University
- Riyadh 11671
- Saudi Arabia
| | - Howbeer Muhamadali
- Department of Biochemistry and Systems Biology
- Institute of Systems
- Molecular and Integrative Biology
- University of Liverpool
- Liverpool L69 7ZB
| | - Malama Chisanga
- School of Chemistry and Manchester Institute of Biotechnology
- University of Manchester
- Manchester
- UK
| | - Haitham AlRabiah
- Department of Pharmaceutical Chemistry
- College of Pharmacy
- King Saud University
- Riyadh
- Saudi Arabia
| | - Cassio A. Lima
- Department of Biochemistry and Systems Biology
- Institute of Systems
- Molecular and Integrative Biology
- University of Liverpool
- Liverpool L69 7ZB
| | - Royston Goodacre
- Department of Biochemistry and Systems Biology
- Institute of Systems
- Molecular and Integrative Biology
- University of Liverpool
- Liverpool L69 7ZB
| |
Collapse
|
9
|
Wu MY, Li WW, Christie G, Setlow P, Li YQ. Characterization of Heterogeneity and Dynamics of Lysis of Single Bacillus subtilis Cells upon Prophage Induction During Spore Germination, Outgrowth, and Vegetative Growth Using Raman Tweezers and Live-Cell Phase-Contrast Microscopy. Anal Chem 2020; 93:1443-1450. [PMID: 33369381 DOI: 10.1021/acs.analchem.0c03341] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A prophage comprises a bacteriophage genome that has integrated into a host bacterium's DNA, which generally permits the cell to grow and divide normally. However, the prophage can be induced by various stresses, or induction can occur spontaneously. After prophage induction, viral replication and production of endolysins begin until the cell lyses and phage particles are released. However, the heterogeneity of prophage induction and lysis of individual cells in a population and the dynamics of a cell undergoing lysis by prophage induction have not been fully characterized. Here, we used Raman tweezers and live-cell phase-contrast microscopy to characterize the Raman spectral and cell length changes that occur during the lysis of individual Bacillus subtilis cells from spores that carry PBSX prophage during spores' germination, outgrowth, and then vegetative growth. Major findings of this work are as follows: (i) After addition of xylose to trigger prophage induction, the intensities of Raman spectral bands associated with nucleic acids of single cells in induced cultures gradually fell to zero, in contrast to the much smaller changes in protein band intensities and no changes in nucleic acid bands in uninduced cultures; (ii) the nucleic acid band intensities from an individual induced cell exhibited a rapid decrease, following a long lag period; (iii) after the addition of nutrient-rich medium with xylose, single spores underwent a long period (228 ± 41.4 min) for germination, outgrowth, and vegetative growth, followed by a short period of cell burst in 1.5 ± 0.8 min at a cell length of 8.2 ± 5.5 μm; (iv) the latent time (Tlatent) between the addition of xylose and the start of cell burst was heterogeneous in cell populations; however, the period (ΔTburst) from the latent time to the completion of cell lysis was quite small; (v) in a poor medium with l-alanine alone, addition of xylose caused prophage induction following spore germination but with longer Tlatent and ΔTburst times and without cell elongation; (vi) spontaneous prophage induction and lysis of individual cells from spores in a minimal nutrient medium were observed without xylose addition, and cell length prior to cell lysis was ∼4.1 μm, but spontaneous prophage induction was not observed in a rich medium; (vii) in a rich medium, addition of xylose at a time well after spore germination and outgrowth significantly shortened the average Tlatent time. The results of this study provide new insights into the heterogeneity and dynamics of lysis of individual B. subtilis cells derived from spores upon prophage induction.
Collapse
Affiliation(s)
- Mei-Yan Wu
- Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353, United States
| | | | - Graham Christie
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, U.K
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, UCONN Health, Farmington, Connecticut 06030-3305, United States
| | - Yong-Qing Li
- Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353, United States.,School of Electronic Engineering, Dongguan University of Technology, Dongguan, Guangdong 523808, P. R. China
| |
Collapse
|
10
|
Kakagianni M, Chatzitzika C, Koutsoumanis KP, Valdramidis VP. The impact of high power ultrasound for controlling spoilage by Alicyclobacillus acidoterrestris: A population and a single spore assessment. INNOV FOOD SCI EMERG 2020. [DOI: 10.1016/j.ifset.2020.102405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
|
11
|
Enhancing Double-Beam Laser Tweezers Raman Spectroscopy (LTRS) for the Photochemical Study of Individual Airborne Microdroplets. Molecules 2019; 24:molecules24183325. [PMID: 31547361 PMCID: PMC6766935 DOI: 10.3390/molecules24183325] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/03/2019] [Accepted: 09/05/2019] [Indexed: 11/23/2022] Open
Abstract
A new device and methodology for vertically coupling confocal Raman microscopy with optical tweezers for the in situ physico- and photochemical studies of individual microdroplets (Ø ≤ 10 µm) levitated in air is presented. The coupling expands the spectrum of studies performed with individual particles using laser tweezers Raman spectroscopy (LTRS) to photochemical processes and spatially resolved Raman microspectroscopy on airborne aerosols. This is the first study to demonstrate photochemical studies and Raman mapping on optically levitated droplets. By using this configuration, photochemical reactions in aerosols of atmospheric interest can be studied on a laboratory scale under realistic conditions of gas-phase composition and relative humidity. Likewise, the distribution of photoproducts within the drop can also be observed with this setup. The applicability of the coupling system was tested by studying the photochemical behavior of microdroplets (5 µm < Ø < 8 µm) containing an aqueous solution of sodium nitrate levitated in air and exposed to narrowed UV radiation (254 ± 25 nm). Photolysis of the levitated NaNO3 microdroplets presented photochemical kinetic differences in comparison with larger NaNO3 droplets (40 µm < Ø < 80 µm), previously photolyzed using acoustic traps, and heterogeneity in the distribution of the photoproducts within the drop.
Collapse
|
12
|
McEvoy B, Rowan NJ. Terminal sterilization of medical devices using vaporized hydrogen peroxide: a review of current methods and emerging opportunities. J Appl Microbiol 2019; 127:1403-1420. [PMID: 31410952 DOI: 10.1111/jam.14412] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 07/03/2019] [Accepted: 07/25/2019] [Indexed: 01/08/2023]
Abstract
Medical devices are an important and growing aspect of healthcare provision and are increasing in complexity to meet established and emerging patient needs. Terminal sterilization plays a vital role in the provision of safe medical devices. While terminal sterilization technologies for medical devices include multiple radiation options, ethylene oxide remains the predominant nonthermal gaseous option, sterilizing c. 50% of all manufactured devices. Vaporized hydrogen peroxide (abbreviated VH2O2 by the International Organization for Standardization) is currently deployed for clinical sterilization applications, where its performance characteristics appear aligned to requirements, constituting a viable alternative low-temperature process for terminal processing of medical devices. However, VH2O2 has operational limitations that create technical challenges for industrial-scale adoption. This timely review provides a succinct overview of VH2O2 in gaseous sterilization and addresses its applicability for terminal sterilization of medical devices. It also describes underappreciated factors such as the occurrence of nonlinear microbial inactivation kinetic plots that may dictate a need to develop a new standard approach to validate VH2O2 for terminal sterilization of medical devices.
Collapse
Affiliation(s)
- B McEvoy
- STERIS Applied Sterilization Technologies, IDA Business and Technology Park, Tullamore, Ireland
| | - N J Rowan
- Bioscience Research Institute, Athlone Institute of Technology, Athlone, Ireland
| |
Collapse
|
13
|
Aspholm ME, Kollerud KK, Høgberg Hansen HC, Granum PE, Christie G, Lindbäck T. Biochemical and mutational analysis of spore cortex-lytic enzymes in the food spoiler Bacillus licheniformis. Food Microbiol 2019; 84:103259. [PMID: 31421778 DOI: 10.1016/j.fm.2019.103259] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/01/2019] [Accepted: 07/03/2019] [Indexed: 12/11/2022]
Abstract
Bacillus licheniformis is frequently associated with food spoilage due to its ability to form highly resistant endospores. The present study reveals that B. licheniformis spore peptidoglycan shares a similar structure to spores of other species of Bacillus. Two enzymatic activities associated with depolymerisation of the cortical peptidoglycan, which represents a crucial step in spore germination, were detected by muropeptide analysis. These include lytic transglycosylase and N-acetylglucosaminidase activity, with non-lytic epimerase activity also being detected. The role of various putative cortex-lytic enzymes that account for the aforementioned activity was investigated by mutational analysis. These analyses indicate that SleB is the major lysin involved in cortex depolymerisation in B. licheniformis spores, with CwlJ and SleL having lesser roles. Collectively, the results of this work indicate that B. licheniformis spores employ a similar approach for cortical depolymerisation during germination as spores of other Bacillus species.
Collapse
Affiliation(s)
- Marina E Aspholm
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Pb 369 Sentrum, 0102, Oslo, Norway
| | - Kristian K Kollerud
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Pb 369 Sentrum, 0102, Oslo, Norway
| | - Helge C Høgberg Hansen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Pb 369 Sentrum, 0102, Oslo, Norway
| | - Per Einar Granum
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Pb 369 Sentrum, 0102, Oslo, Norway
| | - Graham Christie
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom
| | - Toril Lindbäck
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Pb 369 Sentrum, 0102, Oslo, Norway.
| |
Collapse
|
14
|
Intracellular membranes of bacterial endospores are reservoirs for spore core membrane expansion during spore germination. Sci Rep 2018; 8:11388. [PMID: 30061638 PMCID: PMC6065386 DOI: 10.1038/s41598-018-29879-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/16/2018] [Indexed: 11/08/2022] Open
Abstract
Bacterial endospores are formed by certain bacteria, such as Bacillus subtilis or the pathogenic Bacillus anthracis and Clostridioides difficile, to allow survival in environmental conditions which are lethal to vegetative bacteria. The spores possess a particular architecture and molecular inventory which endow them with a remarkable resistance against desiccation, heat and radiation. Another remarkable spore feature is their rapid return to vegetative growth during spore germination and outgrowth. The underlying processes of this latter physiological and morphological transformation involve a number of different events, some of which are mechanistically not entirely understood. One of these events is the expansion of the central spore core, which contains the DNA, RNA and most spore enzymes. To date, it has been unclear how the ~1.3- to 1.6-fold expansion of the core membrane surface area that accompanies core expansion takes place, since this occurs in the absence of significant if any ATP synthesis. In the current work, we demonstrate the presence of intracellular membrane structures in spores located just below the core membrane. During spore germination these internal core membranes disappear when the core size increases, suggesting that they are integrated into the core membrane to allow core expansion. These intracellular membranes are most probably present as more or less compressed vesicles or tubules within the dormant spore core. Investigations of spores from different species suggest that these intracellular membrane structures below the core membrane are a general feature of endospore forming bacteria.
Collapse
|
15
|
Chisanga M, Muhamadali H, Ellis DI, Goodacre R. Surface-Enhanced Raman Scattering (SERS) in Microbiology: Illumination and Enhancement of the Microbial World. APPLIED SPECTROSCOPY 2018; 72:987-1000. [PMID: 29569946 DOI: 10.1177/0003702818764672] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The microbial world forms a huge family of organisms that exhibit the greatest phylogenetic diversity on Earth and thus colonize virtually our entire planet. Due to this diversity and subsequent complex interactions, the vast majority of microorganisms are involved in innumerable natural bioprocesses and contribute an absolutely vital role toward the maintenance of life on Earth, whilst a small minority cause various infectious diseases. The ever-increasing demand for environmental monitoring, sustainable ecosystems, food security, and improved healthcare systems drives the continuous search for inexpensive but reproducible, automated and portable techniques for detection of microbial isolates and understanding their interactions for clinical, environmental, and industrial applications and benefits. Surface-enhanced Raman scattering (SERS) is attracting significant attention for the accurate identification, discrimination and characterization and functional assessment of microbial cells at the single cell level. In this review, we briefly discuss the technological advances in Raman and Fourier transform infrared (FT-IR) instrumentation and their application for the analysis of clinically and industrially relevant microorganisms, biofilms, and biological warfare agents. In addition, we summarize the current trends and future prospects of integrating Raman/SERS-isotopic labeling and cell sorting technologies in parallel, to link genotype-to-phenotype in order to define community function of unculturable microbial cells in mixed microbial communities which possess admirable traits such as detoxification of pollutants and recycling of essential metals.
Collapse
Affiliation(s)
- Malama Chisanga
- School of Chemistry, Manchester Institute of Biotechnology, University of Manchester, UK
| | - Howbeer Muhamadali
- School of Chemistry, Manchester Institute of Biotechnology, University of Manchester, UK
| | - David I Ellis
- School of Chemistry, Manchester Institute of Biotechnology, University of Manchester, UK
| | - Royston Goodacre
- School of Chemistry, Manchester Institute of Biotechnology, University of Manchester, UK
| |
Collapse
|
16
|
Simmert S, Abdosamadi MK, Hermsdorf G, Schäffer E. LED-based interference-reflection microscopy combined with optical tweezers for quantitative three-dimensional microtubule imaging. OPTICS EXPRESS 2018; 26:14499-14513. [PMID: 29877486 DOI: 10.1364/oe.26.014499] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 04/28/2018] [Indexed: 06/08/2023]
Abstract
Optical tweezers combined with various microscopy techniques are a versatile tool for single-molecule force spectroscopy. However, some combinations may compromise measurements. Here, we combined optical tweezers with total-internal-reflection-fluorescence (TIRF) and interference-reflection microscopy (IRM). Using a light-emitting diode (LED) for IRM illumination, we show that single microtubules can be imaged with high contrast. Furthermore, we converted the IRM interference pattern of an upward bent microtubule to its three-dimensional (3D) profile calibrated against the optical tweezers and evanescent TIRF field. In general, LED-based IRM is a powerful method for high-contrast 3D microscopy.
Collapse
|
17
|
Esfahani SS, Emtiazi G, Rabbani M. Germination assay of Bacillus amyloliquefaciens as a spore-based biosensing method for detection of cell wall destruction antibiotics. JOURNAL OF FOOD MEASUREMENT AND CHARACTERIZATION 2018. [DOI: 10.1007/s11694-017-9657-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
18
|
Nuding DL, Gough RV, Venkateswaran KJ, Spry JA, Tolbert MA. Laboratory Investigations on the Survival of Bacillus subtilis Spores in Deliquescent Salt Mars Analog Environments. ASTROBIOLOGY 2017; 17:997-1008. [PMID: 29048223 DOI: 10.1089/ast.2016.1545] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Observed features such as recurring slope lineae suggest that liquid water may exist on the surface and near-subsurface of Mars today. The presence of this liquid water, likely in the form of a brine, has important implications for the present-day water cycle, habitability, and planetary protection policies. It is possible that this water is formed, at least partially, by deliquescence of salts, a process during which hygroscopic salts absorb water vapor from the atmosphere and form a saturated liquid brine. We performed laboratory experiments to examine the ability of Bacillus subtilis (B-168) spores, alone or mixed with calcium perchlorate salt (Ca(ClO4)2), to form liquid water via deliquescence under Mars-relevant conditions. Spore survival after exposure to these conditions was examined. An environmental chamber was used to expose the samples to temperature and relative humidity (RH) values similar to those found on Mars, and Raman microscopy was used to identify the phases of water and salt that were present and to confirm the presence of spores. We found that B-168 spores did not condense any detectable water vapor on their own during the diurnal cycle, even at 100% RH. However, when spores were mixed with perchlorate salt, the entire sample deliquesced at low RH values, immersing the spores in a brine solution during the majority of the simulated martian temperature and humidity cycle. After exposure to the simulated diurnal cycles and, in some cases, perchlorate brine, the impact of each environmental scenario on spore survival was estimated by standard plate assay. We found that, if there are deliquescent salts in contact with spores, there is a mechanism for the spores to acquire liquid water starting with only atmospheric water vapor as the H2O source. Also, neither crystalline nor liquid Ca(ClO4)2 is sporicidal despite the low water activity. Key Words: Raman microscopy-Mars-Planetary protection-Salts-Water activity. Astrobiology 17, 997-1008.
Collapse
Affiliation(s)
- Danielle L Nuding
- 1 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California
| | - Raina V Gough
- 2 Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado
- 3 Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado
| | | | | | - Margaret A Tolbert
- 2 Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado
- 3 Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado
| |
Collapse
|
19
|
Raman Plus X: Biomedical Applications of Multimodal Raman Spectroscopy. SENSORS 2017; 17:s17071592. [PMID: 28686212 PMCID: PMC5539739 DOI: 10.3390/s17071592] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/04/2017] [Accepted: 07/04/2017] [Indexed: 12/11/2022]
Abstract
Raman spectroscopy is a label-free method of obtaining detailed chemical information about samples. Its compatibility with living tissue makes it an attractive choice for biomedical analysis, yet its translation from a research tool to a clinical tool has been slow, hampered by fundamental Raman scattering issues such as long integration times and limited penetration depth. In this review we detail the how combining Raman spectroscopy with other techniques yields multimodal instruments that can help to surmount the translational barriers faced by Raman alone. We review Raman combined with several optical and non-optical methods, including fluorescence, elastic scattering, OCT, phase imaging, and mass spectrometry. In each section we highlight the power of each combination along with a brief history and presentation of representative results. Finally, we conclude with a perspective detailing both benefits and challenges for multimodal Raman measurements, and give thoughts on future directions in the field.
Collapse
|
20
|
Kakagianni M, Aguirre JS, Lianou A, Koutsoumanis KP. Effect of storage temperature on the lag time of Geobacillus stearothermophilus individual spores. Food Microbiol 2017. [PMID: 28648296 DOI: 10.1016/j.fm.2017.04.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The lag times (λ) of Geobacillus stearothermophilus single spores were studied at different storage temperatures ranging from 45 to 59 °C using the Bioscreen C method. A significant variability of λ was observed among individual spores at all temperatures tested. The storage temperature affected both the position and the spread of the λ distributions. The minimum mean value of λ (i.e. 10.87 h) was observed at 55 °C, while moving away from this temperature resulted in an increase for both the mean and standard deviation of λ. A Cardinal Model with Inflection (CMI) was fitted to the reverse mean λ, and the estimated values for the cardinal parameters Tmin, Tmax, Topt and the optimum mean λ of G. stearothermophilus were found to be 38.1, 64.2, 53.6 °C and 10.3 h, respectively. To interpret the observations, a probabilistic growth model for G. stearothermophilus individual spores, taking into account λ variability, was developed. The model describes the growth of a population, initially consisting of N0 spores, over time as the sum of cells in each of the N0 imminent subpopulations originating from a single spore. Growth simulations for different initial contamination levels showed that for low N0 the number of cells in the population at any time is highly variable. An increase in N0 to levels exceeding 100 spores results in a significant decrease of the above variability and a shorter λ of the population. Considering that the number of G. stearothermophilus surviving spores in the final product is usually very low, the data provided in this work can be used to evaluate the probability distribution of the time-to-spoilage and enable decision-making based on the "acceptable level of risk".
Collapse
Affiliation(s)
- Myrsini Kakagianni
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Juan S Aguirre
- Laboratorio de Microbiología y Probioticos, INTA, Universidad de Chile, Avenida El Líbano 5524, Macul, Santiago, Chile
| | - Alexandra Lianou
- Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, School of Food, Biotechnology and Development, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece
| | - Konstantinos P Koutsoumanis
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.
| |
Collapse
|
21
|
Ha TMH, Yong D, Lee EMY, Kumar P, Lee YK, Zhou W. Activation and inactivation of Bacillus pumilus spores by kiloelectron volt X-ray irradiation. PLoS One 2017; 12:e0177571. [PMID: 28493969 PMCID: PMC5426783 DOI: 10.1371/journal.pone.0177571] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 04/28/2017] [Indexed: 11/30/2022] Open
Abstract
In this study, we investigated the inactivation efficacy of endospore-forming bacteria, Bacillus pumilus, irradiated by low-energy X-rays of different beam qualities. The different low-energy X-rays studied had cut-off energies of 50, 100 and 150 keV. Bacillus pumilus spores (in biological indicator strips) were irradiated at step doses between 6.5 to 390 Gy. The resulting bacteria populations were then quantified by a pour plate method. Results showed that X-rays of lower energies were more effective in inactivating bacterial spores. In addition, an increment in bacterial population was observed at doses below 13Gy. We attributed this increase to a radiation-induced activation of bacterial spores. Four kinetic models were then evaluated for their prediction of bacterial spore behavior under irradiation. This included: (i) first-order kinetics model; (ii) Shull model; (iii) Sapru model; and (iv) probabilistic model. From R2 and AIC analyses, we noted that the probabilistic model performed the best, followed by the Sapru model. We highlighted that for simplicity in curve fitting the Sapru model should be used instead of the probabilistic model. A 12-log reduction in bacterial population (corresponding to a sterility assurance level of 10−6 as required in the sterilization of medical devices) was computed to be achievable at doses of 1000, 1600 and 2300 Gy for the three different X-ray cut-off energies respectively. These doses are an order in magnitude lesser than that required in gamma irradiation. This highlights the applicability of cheaper and safer table-top X-ray sources for sterilization application.
Collapse
Affiliation(s)
- Thi Mai Hoa Ha
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
- * E-mail:
| | - Derrick Yong
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
| | - Elizabeth Mei Yin Lee
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore
| | - Prathab Kumar
- Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Yuan Kun Lee
- Department of Microbiology, National University of Singapore, Singapore, Singapore
| | - Weibiao Zhou
- Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, Singapore, Singapore
| |
Collapse
|
22
|
Carney RP, Hazari S, Colquhoun M, Tran D, Hwang B, Mulligan MS, Bryers JD, Girda E, Leiserowitz GS, Smith ZJ, Lam KS. Multispectral Optical Tweezers for Biochemical Fingerprinting of CD9-Positive Exosome Subpopulations. Anal Chem 2017; 89:5357-5363. [PMID: 28345878 DOI: 10.1021/acs.analchem.7b00017] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Extracellular vesicles (EVs), including exosomes, are circulating nanoscale particles heavily implicated in cell signaling and can be isolated in vast numbers from human biofluids. Study of their molecular profiling and materials properties is currently underway for purposes of describing a variety of biological functions and diseases. However, the large, and as yet largely unquantified, variety of EV subpopulations differing in composition, size, and likely function necessitates characterization schemes capable of measuring single vesicles. Here we describe the first application of multispectral optical tweezers (MS-OTs) to single vesicles for molecular fingerprinting of EV subpopulations. This versatile imaging platform allows for sensitive measurement of Raman chemical composition (e.g., variation in protein, lipid, cholesterol, nucleic acids), coupled with discrimination by fluorescence markers. For exosomes isolated by ultracentrifugation, we use MS-OTs to interrogate the CD9-positive subpopulations via antibody fluorescence labeling and Raman spectra measurement. We report that the CD9-positive exosome subset exhibits reduced component concentration per vesicle and reduced chemical heterogeneity compared to the total purified EV population. We observed that specific vesicle subpopulations are present across exosomes isolated from cell culture supernatant of several clonal varieties of mesenchymal stromal cells and also from plasma and ascites isolated from human ovarian cancer patients.
Collapse
Affiliation(s)
- Randy P Carney
- Department of Biochemistry and Molecular Medicine, University of California Davis , Sacramento, California 95817, United States
| | - Sidhartha Hazari
- Department of Biochemistry and Molecular Medicine, University of California Davis , Sacramento, California 95817, United States
| | - Macalistair Colquhoun
- Department of Biochemistry and Molecular Medicine, University of California Davis , Sacramento, California 95817, United States
| | - Di Tran
- Department of Biochemistry and Molecular Medicine, University of California Davis , Sacramento, California 95817, United States
| | - Billanna Hwang
- Department of Surgery, University of Washington , 850 Republican Street, Seattle, Washington 98195-0005, United States
| | - Michael S Mulligan
- Department of Surgery, University of Washington , 850 Republican Street, Seattle, Washington 98195-0005, United States
| | - James D Bryers
- Department of Bioengineering, University of Washington , 3720 15th Avenue NE, Seattle, Washington 98195, United States
| | - Eugenia Girda
- Division of Gynecologic Oncology, University of California Davis Medical Center , Sacramento, California 98517, United States
| | - Gary S Leiserowitz
- Division of Gynecologic Oncology, University of California Davis Medical Center , Sacramento, California 98517, United States
| | - Zachary J Smith
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China , Hefei, Anhui 230027 China
| | - Kit S Lam
- Department of Biochemistry and Molecular Medicine, University of California Davis , Sacramento, California 95817, United States.,Division of Hematology/Oncology, University of California Davis Cancer Center , Sacramento, California 95817, United States
| |
Collapse
|
23
|
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.
Collapse
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
| |
Collapse
|
24
|
Leggett M, Setlow P, Sattar S, Maillard JY. Assessing the activity of microbicides against bacterial spores: knowledge and pitfalls. J Appl Microbiol 2016; 120:1174-80. [DOI: 10.1111/jam.13061] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/25/2015] [Accepted: 10/14/2015] [Indexed: 11/27/2022]
Affiliation(s)
- M.J. Leggett
- Cardiff School of Pharmacy and Pharmaceutical Sciences; Cardiff University; Cardiff UK
| | | | - S.A. Sattar
- Faculty of Medicine; University of Ottawa; Ottawa ON Canada
| | - J.-Y. Maillard
- Cardiff School of Pharmacy and Pharmaceutical Sciences; Cardiff University; Cardiff UK
| |
Collapse
|
25
|
Wells-Bennik MH, Eijlander RT, den Besten HM, Berendsen EM, Warda AK, Krawczyk AO, Nierop Groot MN, Xiao Y, Zwietering MH, Kuipers OP, Abee T. Bacterial Spores in Food: Survival, Emergence, and Outgrowth. Annu Rev Food Sci Technol 2016; 7:457-82. [DOI: 10.1146/annurev-food-041715-033144] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Marjon H.J. Wells-Bennik
- TI Food and Nutrition, 6700 AN Wageningen, The Netherlands
- NIZO Food Research, 6718 ZB Ede, The Netherlands;
| | - Robyn T. Eijlander
- TI Food and Nutrition, 6700 AN Wageningen, The Netherlands
- NIZO Food Research, 6718 ZB Ede, The Netherlands;
| | - Heidy M.W. den Besten
- TI Food and Nutrition, 6700 AN Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands
| | - Erwin M. Berendsen
- TI Food and Nutrition, 6700 AN Wageningen, The Netherlands
- NIZO Food Research, 6718 ZB Ede, The Netherlands;
- Molecular Genetics Department, University of Groningen, 9700 AB Groningen, The Netherlands
| | - Alicja K. Warda
- TI Food and Nutrition, 6700 AN Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands
- Wageningen UR Food & Biobased Research, 6700 AA Wageningen, The Netherlands
| | - Antonina O. Krawczyk
- TI Food and Nutrition, 6700 AN Wageningen, The Netherlands
- Molecular Genetics Department, University of Groningen, 9700 AB Groningen, The Netherlands
| | - Masja N. Nierop Groot
- TI Food and Nutrition, 6700 AN Wageningen, The Netherlands
- Wageningen UR Food & Biobased Research, 6700 AA Wageningen, The Netherlands
| | - Yinghua Xiao
- TI Food and Nutrition, 6700 AN Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands
| | - Marcel H. Zwietering
- TI Food and Nutrition, 6700 AN Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands
| | - Oscar P. Kuipers
- TI Food and Nutrition, 6700 AN Wageningen, The Netherlands
- Molecular Genetics Department, University of Groningen, 9700 AB Groningen, The Netherlands
| | - Tjakko Abee
- TI Food and Nutrition, 6700 AN Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University, 6700 AA Wageningen, The Netherlands
| |
Collapse
|
26
|
Lin M, Xu B, Yao H, Shen A, Hu J. An in vivo quantitative Raman-pH sensor of arterial blood based on laser trapping of erythrocytes. Analyst 2016; 141:3027-32. [DOI: 10.1039/c5an02315g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A continuous and noninvasive approach is appliedin vivoto measure the arterial blood pH quantitatively.
Collapse
Affiliation(s)
- Manman Lin
- School of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- China
| | - Bin Xu
- Laboratory of Biophysics
- Guangxi Academy of Sciences
- Nanning 530003
- China
| | - Huilu Yao
- Laboratory of Biophysics
- Guangxi Academy of Sciences
- Nanning 530003
- China
| | - Aiguo Shen
- School of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- China
| | - Jiming Hu
- School of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan 430072
- China
| |
Collapse
|
27
|
Pandey R, Pieper GH, Beek AT, Vischer NO, Smelt JP, Manders EM, Brul S. Quantifying the effect of sorbic acid, heat and combination of both on germination and outgrowth of Bacillus subtilis spores at single cell resolution. Food Microbiol 2015; 52:88-96. [DOI: 10.1016/j.fm.2015.06.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 05/10/2015] [Accepted: 06/19/2015] [Indexed: 11/26/2022]
|
28
|
Redding B, Schwab M, Pan YL. Raman Spectroscopy of Optically Trapped Single Biological Micro-Particles. SENSORS 2015; 15:19021-46. [PMID: 26247952 PMCID: PMC4570358 DOI: 10.3390/s150819021] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 06/30/2015] [Accepted: 07/27/2015] [Indexed: 12/20/2022]
Abstract
The combination of optical trapping with Raman spectroscopy provides a powerful method for the study, characterization, and identification of biological micro-particles. In essence, optical trapping helps to overcome the limitation imposed by the relative inefficiency of the Raman scattering process. This allows Raman spectroscopy to be applied to individual biological particles in air and in liquid, providing the potential for particle identification with high specificity, longitudinal studies of changes in particle composition, and characterization of the heterogeneity of individual particles in a population. In this review, we introduce the techniques used to integrate Raman spectroscopy with optical trapping in order to study individual biological particles in liquid and air. We then provide an overview of some of the most promising applications of this technique, highlighting the unique types of measurements enabled by the combination of Raman spectroscopy with optical trapping. Finally, we present a brief discussion of future research directions in the field.
Collapse
Affiliation(s)
- Brandon Redding
- U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, MD 20783, USA.
| | - Mark Schwab
- U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, MD 20783, USA.
| | - Yong-le Pan
- U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, MD 20783, USA.
| |
Collapse
|
29
|
Huser T, Chan J. Raman spectroscopy for physiological investigations of tissues and cells. Adv Drug Deliv Rev 2015; 89:57-70. [PMID: 26144996 DOI: 10.1016/j.addr.2015.06.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 06/08/2015] [Accepted: 06/26/2015] [Indexed: 12/29/2022]
Abstract
Raman micro-spectroscopy provides a convenient non-destructive and location-specific means of probing cellular physiology and tissue physiology at sub-micron length scales. By probing the vibrational signature of molecules and molecular groups, the distribution and metabolic products of small molecules that cannot be labeled with fluorescent dyes can be analyzed. This method works well for molecular concentrations in the micro-molar range and has been demonstrated as a valuable tool for monitoring drug-cell interactions. If the small molecule of interest does not contain groups that would allow for a discrimination against cytoplasmic background signals, "labeling" of the molecule by isotope substitution or by incorporating other unique small groups, e.g. alkynes provides a stable signal even for time-lapse imaging such compounds in living cells. In this review we highlight recent progress in assessing the physiology of cells and tissue by Raman spectroscopy and imaging.
Collapse
|
30
|
High-precision fitting measurements of the kinetics of size changes during germination of individual Bacillus spores. Appl Environ Microbiol 2015; 80:4606-15. [PMID: 24837375 DOI: 10.1128/aem.01204-14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
High-precision measurements of size changes of individual bacterial spores based on ellipse fitting to bright-field images recorded with a digital camera were employed to monitor the germination of Bacillus spores with a precision of ~5 nm. To characterize the germination of individual spores, we recorded bright-field and phase-contrast images and found that the timing of changes in their normalized intensities coincided, so the bright-field images can be used to characterize spore size and refractility changes during germination. The major conclusions from this work were as follows. (i) The sizes of germinating B. cereus spores were nearly unchanged until Trelease, the time of the completion of CaDPA (a 1:1 chelate of Ca(2+) and dipicolinic acid [DPA]) release after addition of nutrient germinants. (ii) The minor axis of germinating B. cereus spores rapidly increased by ~50 nm in a few seconds right after Trelease, while the major axis was slightly decreased or unchanged. Both the minor and major axes remained unchanged for a further 30 to 45 s and then increased by 100 to 200 nm by Tlys, the time of completion of cortex lysis. (iii) Individual spores in a population showed significant heterogeneity in the timing of germination events, such as Trelease and Tlys, but also variation in size changes during germination. (iv) Bacillus subtilis wild-type spores, B. subtilis spores lacking the cortex-lytic enzyme CwlJ, and wild-type Bacillus megaterium spores showed similar kinetics of size changes during nutrient germination. The size increases in germinating spores probably result from uptake of water and cortex lysis after completion of CaDPA release.
Collapse
|
31
|
Alzahrani OM, Moir A. Spore germination and germinant receptor genes in wild strains of Bacillus subtilis. J Appl Microbiol 2014; 117:741-9. [PMID: 24916603 DOI: 10.1111/jam.12566] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 06/03/2014] [Accepted: 06/04/2014] [Indexed: 11/25/2022]
Abstract
AIMS To compare the germination of laboratory and wild strains of Bacillus subtilis. METHODS AND RESULTS The spore germination of B. subtilis 168 (subsp. subtilis) was compared with that of the laboratory strain W23 (subsp. spizizenii) and desert-sourced isolates, including one member of subsp. subtilis (RO-NN-1), strains TU-B-10, RO-E-2, N10 and DV1-B-1, (all subsp. spizizenii), the B. mojavensis strain RO-H-1 and a B. subtilis natto strain. All germinated in L-alanine, although some were slower, and some 10-fold less sensitive to germinant. All germinated in calcium dipicolinate (CaDPA). Germination in asparagine, glucose, fructose + KCl was slow and incomplete in many of the strains, and decoating RO-NN-1 and W23 spores did not restore germination rates. Comparing the sequences of B. subtilis strains 168, RO-NN-1, W23, TU-B-10 and DV1-B-1, the operons encoding GerA, B and K germinant receptors were intact, although the two additional operons yndDEF and yfkQRST had suffered deletions or were absent in several spizizenii strains. CONCLUSIONS Wild strains possess an efficient germination machinery for L-alanine germination. AGFK germination is often less efficient, the gerB genes more diverged, and the two germinant receptor operons of unknown function have been lost from the genome in many subsp. spizizenii strains. SIGNIFICANCE AND IMPACT OF THE STUDY The two major subspecies of B. subtilis have conserved GerA receptor function, confirming its importance, at least in the natural environments of these strains.
Collapse
Affiliation(s)
- O M Alzahrani
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK; Department of Biotechnology, Taif University, Taif, Saudi Arabia
| | | |
Collapse
|
32
|
Kong L, Chan J. A Rapidly Modulated Multifocal Detection Scheme for Parallel Acquisition of Raman Spectra from a 2-D Focal Array. Anal Chem 2014; 86:6604-9. [DOI: 10.1021/ac5012188] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lingbo Kong
- Center
for Biophotonics, University of California, Davis, Sacramento, California 95817, United States
| | - James Chan
- Center
for Biophotonics, University of California, Davis, Sacramento, California 95817, United States
- Department
of Pathology and Laboratory Medicine, University of California, Davis, Sacramento, California 95817, United States
| |
Collapse
|
33
|
|
34
|
Chen Y, Ray WK, Helm RF, Melville SB, Popham DL. Levels of germination proteins in Bacillus subtilis dormant, superdormant, and germinating spores. PLoS One 2014; 9:e95781. [PMID: 24752279 PMCID: PMC3994143 DOI: 10.1371/journal.pone.0095781] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 03/31/2014] [Indexed: 12/24/2022] Open
Abstract
Bacterial endospores exhibit extreme resistance to most conditions that rapidly kill other life forms, remaining viable in this dormant state for centuries or longer. While the majority of Bacillus subtilis dormant spores germinate rapidly in response to nutrient germinants, a small subpopulation termed superdormant spores are resistant to germination, potentially evading antibiotic and/or decontamination strategies. In an effort to better understand the underlying mechanisms of superdormancy, membrane-associated proteins were isolated from populations of B. subtilis dormant, superdormant, and germinated spores, and the relative abundance of 11 germination-related proteins was determined using multiple-reaction-monitoring liquid chromatography-mass spectrometry assays. GerAC, GerKC, and GerD were significantly less abundant in the membrane fractions obtained from superdormant spores than those derived from dormant spores. The amounts of YpeB, GerD, PrkC, GerAC, and GerKC recovered in membrane fractions decreased significantly during germination. Lipoproteins, as a protein class, decreased during spore germination, while YpeB appeared to be specifically degraded. Some protein abundance differences between membrane fractions of dormant and superdormant spores resemble protein changes that take place during germination, suggesting that the superdormant spore isolation procedure may have resulted in early, non-committal germination-associated changes. In addition to low levels of germinant receptor proteins, a deficiency in the GerD lipoprotein may contribute to heterogeneity of spore germination rates. Understanding the reasons for superdormancy may allow for better spore decontamination procedures.
Collapse
Affiliation(s)
- Yan Chen
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - W. Keith Ray
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Richard F. Helm
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Stephen B. Melville
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - David L. Popham
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
| |
Collapse
|
35
|
Zhou T, Dong Z, Setlow P, Li YQ. Kinetics of germination of individual spores of Geobacillus stearothermophilus as measured by raman spectroscopy and differential interference contrast microscopy. PLoS One 2013; 8:e74987. [PMID: 24058645 PMCID: PMC3772816 DOI: 10.1371/journal.pone.0074987] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 08/07/2013] [Indexed: 11/19/2022] Open
Abstract
Geobacillus stearothermophilus is a gram-positive, thermophilic bacterium, spores of which are very heat resistant. Raman spectroscopy and differential interference contrast microscopy were used to monitor the kinetics of germination of individual spores of G. stearothermophilus at different temperatures, and major conclusions from this work were as follows. 1) The CaDPA level of individual G. stearothermophilus spores was similar to that of Bacillus spores. However, the Raman spectra of protein amide bands suggested there are differences in protein structure in spores of G. stearothermophilus and Bacillus species. 2) During nutrient germination of G. stearothermophilus spores, CaDPA was released beginning after a lag time (Tlag) between addition of nutrient germinants and initiation of CaDPA release. CaDPA release was complete at Trelease, and ΔTrelease (Trelease – Tlag) was 1–2 min. 3) Activation by heat or sodium nitrite was essential for efficient nutrient germination of G. stearothermophilus spores, primarily by decreasing Tlag values. 4) Values of Tlag and Trelease were heterogeneous among individual spores, but ΔTrelease values were relatively constant. 5) Temperature had major effects on nutrient germination of G. stearothermophilus spores, as at temperatures below 65°C, average Tlag values increased significantly. 6) G. stearothermophilus spore germination with exogenous CaDPA or dodecylamine was fastest at 65°C, with longer Tlag values at lower temperatures. 7) Decoating of G. stearothermophilus spores slowed nutrient germination slightly and CaDPA germination significantly, but increased dodecylamine germination markedly. These results indicate that the dynamics and heterogeneity of the germination of individual G. stearothermophilus spores are generally similar to that of Bacillus species.
Collapse
Affiliation(s)
- Tingting Zhou
- Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Department of Physics, East Carolina University, Greenville, North Carolina, United States of America
| | - Zhiyang Dong
- Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Peter Setlow
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Yong-qing Li
- Department of Physics, East Carolina University, Greenville, North Carolina, United States of America
- * E-mail:
| |
Collapse
|
36
|
Optical tweezers for medical diagnostics. Anal Bioanal Chem 2013; 405:5671-7. [DOI: 10.1007/s00216-013-6919-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Revised: 03/11/2013] [Accepted: 03/14/2013] [Indexed: 12/18/2022]
|
37
|
Expression level of Bacillus subtilis germinant receptors determines the average rate but not the heterogeneity of spore germination. J Bacteriol 2013; 195:1735-40. [PMID: 23396907 DOI: 10.1128/jb.02212-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Germination of Bacillus subtilis spores can be triggered by the binding of specific nutrients, called germinants, to germinant receptors (GRs) in the spore's inner membrane. This interaction eventually initiates, with variable time delays, the release of dipicolinic acid and cations from the spore core--a key step in spore germination. The kinetics of this process are highly heterogeneous for individual spores. In this work, we sought to investigate how the germination heterogeneity was controlled. In particular, we tested whether the rates of germination were determined by GR levels, which vary from spore to spore due to stochastic gene expression. Both the expression levels of GRs and the germination rate were measured in single spores, and the experimental results were compared to theoretical predictions. Our results indicated that the variation in the expression levels of GRs was not the primary factor that controls spore germination heterogeneity. Two alternative hypotheses are discussed in light of this experimental discovery.
Collapse
|
38
|
Chan JW. Recent advances in laser tweezers Raman spectroscopy (LTRS) for label-free analysis of single cells. JOURNAL OF BIOPHOTONICS 2013; 6:36-48. [PMID: 23175434 DOI: 10.1002/jbio.201200143] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 10/15/2012] [Accepted: 10/28/2012] [Indexed: 05/19/2023]
Abstract
Laser tweezers Raman spectroscopy (LTRS), a technique that integrates optical tweezers with confocal Raman spectroscopy, is a variation of micro-Raman spectroscopy that enables the manipulation and biochemical analysis of single biological particles in suspension. This article provides an overview of the LTRS method, with an emphasis on highlighting recent advances over the past several years in the development of the technology and several new biological and biomedical applications that have been demonstrated. A perspective on the future developments of this powerful cytometric technology will also be presented.
Collapse
Affiliation(s)
- James W Chan
- Department of Pathology and Laboratory Medicine, University of California, Davis, Sacramento, CA 95817, USA.
| |
Collapse
|
39
|
Activation of Bacillus spores at moderately elevated temperatures (30–33 °C). Antonie van Leeuwenhoek 2012; 103:693-700. [DOI: 10.1007/s10482-012-9839-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Accepted: 10/20/2012] [Indexed: 10/27/2022]
|
40
|
Butzin XY, Troiano AJ, Coleman WH, Griffiths KK, Doona CJ, Feeherry FE, Wang G, Li YQ, Setlow P. Analysis of the effects of a gerP mutation on the germination of spores of Bacillus subtilis. J Bacteriol 2012; 194:5749-58. [PMID: 22904285 PMCID: PMC3486119 DOI: 10.1128/jb.01276-12] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 08/08/2012] [Indexed: 12/28/2022] Open
Abstract
As previously reported, gerP Bacillus subtilis spores were defective in nutrient germination triggered via various germinant receptors (GRs), and the defect was eliminated by severe spore coat defects. The gerP spores' GR-dependent germination had a longer lag time between addition of germinants and initiation of rapid release of spores' dipicolinic acid (DPA), but times for release of >90% of DPA from individual spores were identical for wild-type and gerP spores. The gerP spores were also defective in GR-independent germination by DPA with its associated Ca(2+) divalent cation (CaDPA) but germinated better than wild-type spores with the GR-independent germinant dodecylamine. The gerP spores exhibited no increased sensitivity to hypochlorite, suggesting that these spores have no significant coat defect. Overexpression of GRs in gerP spores did lead to faster germination via the overexpressed GR, but this was still slower than germination of comparable gerP(+) spores. Unlike wild-type spores, for which maximal nutrient germinant concentrations were between 500 μM and 2 mM for l-alanine and ≤10 mM for l-valine, rates of gerP spore germination increased up to between 200 mM and 1 M l-alanine and 100 mM l-valine, and at 1 M l-alanine, the rates of germination of wild-type and gerP spores with or without all alanine racemases were almost identical. A high pressure of 150 MPa that triggers spore germination by activating GRs also triggered germination of wild-type and gerP spores identically. All these results support the suggestion that GerP proteins facilitate access of nutrient germinants to their cognate GRs in spores' inner membrane.
Collapse
Affiliation(s)
- Xuan Yi Butzin
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Anthony J. Troiano
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - William H. Coleman
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Keren K. Griffiths
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Christopher J. Doona
- U.S. Army—Natick Soldier RD&E Center, Warfighter Directorate, Natick, Massachusetts, USA
| | - Florence E. Feeherry
- U.S. Army—Natick Soldier RD&E Center, Warfighter Directorate, Natick, Massachusetts, USA
| | - Guiwen Wang
- Department of Physics, East Carolina University, Greenville, North Carolina, USA
| | - Yong-qing Li
- Department of Physics, East Carolina University, Greenville, North Carolina, USA
| | - Peter Setlow
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut, USA
| |
Collapse
|
41
|
Løvdal IS, From C, Madslien EH, Romundset KCS, Klufterud E, Rosnes JT, Granum PE. Role of the gerA operon in L-alanine germination of Bacillus licheniformis spores. BMC Microbiol 2012; 12:34. [PMID: 22420404 PMCID: PMC3359204 DOI: 10.1186/1471-2180-12-34] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 03/15/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The genome of Bacillus licheniformis DSM 13 harbours three neighbouring open reading frames showing protein sequence similarities to the proteins encoded from the Bacillus subtilis subsp. subtilis 168 gerA operon, GerAA, GerAB and GerAC. In B. subtilis, these proteins are assumed to form a germinant receptor involved in spore germination induced by the amino acid L-alanine. RESULTS In this study we show that disruption of the gerAA gene in B. licheniformis MW3 hamper L-alanine and casein hydrolysate-triggered spore germination, measured by absorbance at 600 nm and confirmed by phase contrast microscopy. This ability was restored by complementation with a plasmid-borne copy of the gerA locus. Addition of D-alanine in the casein hydrolysate germination assay abolished germination of both B. licheniformis MW3 and the complementation mutant. Germination of both B. licheniformis MW3 and the gerA disruption mutant was induced by the non-nutrient germinant Ca2+-Dipicolinic acid. CONCLUSIONS These results demonstrate that the B. licheniformis MW3 gerA locus is involved in germination induced by L-alanine and potentially other components present in casein hydrolysate.
Collapse
Affiliation(s)
- Irene S Løvdal
- Nofima AS, Department of Process Technology, Måltidets hus, Richard Johnsens gate 4, P Box 8034, N-4068 Stavanger, Norway
| | | | | | | | | | | | | |
Collapse
|
42
|
Levels of germination proteins in dormant and superdormant spores of Bacillus subtilis. J Bacteriol 2012; 194:2221-7. [PMID: 22343299 DOI: 10.1128/jb.00151-12] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Bacillus subtilis spores that germinated poorly with saturating levels of nutrient germinants, termed superdormant spores, were separated from the great majority of dormant spore populations that germinated more rapidly. These purified superdormant spores (1.5 to 3% of spore populations) germinated extremely poorly with the germinants used to isolate them but better with germinants targeting germinant receptors not activated in superdormant spore isolation although not as well as the initial dormant spores. The level of β-galactosidase from a gerA-lacZ fusion in superdormant spores isolated by germination via the GerA germinant receptor was identical to that in the initial dormant spores. Levels of the germination proteins GerD and SpoVAD were also identical in dormant and superdormant spores. However, levels of subunits of a germinant receptor or germinant receptors activated in superdormant spore isolation were 6- to 10-fold lower than those in dormant spores, while levels of subunits of germinant receptors not activated in superdormant spore isolation were only ≤ 2-fold lower. These results indicate that (i) levels of β-galactosidase from lacZ fusions to operons encoding germinant receptors may not be an accurate reflection of actual germinant receptor levels in spores and (ii) a low level of a specific germinant receptor or germinant receptors is a major cause of spore superdormancy.
Collapse
|
43
|
Zhang P, Kong L, Wang G, Scotland M, Ghosh S, Setlow B, Setlow P, Li YQ. Analysis of the slow germination of multiple individual superdormant Bacillus subtilis spores using multifocus Raman microspectroscopy and differential interference contrast microscopy. J Appl Microbiol 2012; 112:526-36. [DOI: 10.1111/j.1365-2672.2011.05230.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
44
|
Kong L, Setlow P, Li YQ. Analysis of the Raman spectra of Ca2+-dipicolinic acid alone and in the bacterial spore core in both aqueous and dehydrated environments. Analyst 2012; 137:3683-9. [DOI: 10.1039/c2an35468c] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
45
|
Kong L, Zhang P, Setlow P, Li YQ. Multifocus confocal Raman microspectroscopy for rapid single-particle analysis. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:120503. [PMID: 22191908 DOI: 10.1117/1.3662456] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have developed a multifocus confocal Raman microspectroscopy system that allows simultaneous analyses of ≈ 80 individual biological or airborne microparticles based on a precise image-guided technique. Multiple individual particles adhered in random positions on a coverslip were illuminated by a multifocus excitation pattern formed by rapidly steering a single laser beam with a pair of galvo-mirrors, and their Raman scatterings were synchronously projected with another galvo-mirror to different rows of a CCD chip for parallel spectroscopic analyses. We show that this technique can be used to rapidly identify single airborne particles or bacteria collected on a slide and to monitor germination dynamics of multiple bacterial spores in real-time.
Collapse
|
46
|
Abstract
Bacterial endospores are some of the most resilient forms of life known to us, with their persistent survival capability resulting from a complex and effective structural organization. The outer membrane of endospores is surrounded by the densely packed endospore coat and exosporium, containing amyloid or amyloid-like proteins. In fact, it is the impenetrable composition of the endospore coat and the exosporium that makes staining methodologies for endospore detection complex and challenging. Therefore, a plausible strategy for facile and expedient staining would be to target components of the protective surface layers of the endospores. Instead of targeting endogenous markers encapsulated in the spores, here we demonstrated staining of these dormant life entities that targets the amyloid domains, i.e., the very surface components that make the coats of these species impenetrable. Using an amyloid staining dye, thioflavin T (ThT), we examined this strategy. A short incubation of bacillus endospore suspensions with ThT, under ambient conditions, resulted in (i) an enhancement of the fluorescence of ThT and (ii) the accumulation of ThT in the endospores, affording fluorescence images with excellent contrast ratios. Fluorescence images revealed that ThT tends to accumulate in the surface regions of the endospores. The observed fluorescence enhancement and dye accumulation, coupled with the sensitivity of emission techniques, provide an effective and rapid means of staining endospores without the inconvenience of pre- or posttreatment of samples.
Collapse
|
47
|
Quantitative analysis of spatial-temporal correlations during germination of spores of Bacillus Species. J Bacteriol 2011; 193:3765-72. [PMID: 21622756 DOI: 10.1128/jb.05154-11] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Bacteria of Bacillus species sporulate upon starvation, and the resultant dormant spores germinate when the environment appears likely to allow the resumption of vegetative growth. Normally, the rates of germination of individual spores in populations are very heterogeneous, and the current work has investigated whether spore-to-spore communication enhances the synchronicity of germination. In order to do this work, time-lapse optical images of thousands of individual spores were captured during germination, and an image analysis algorithm was developed to do the following: (i) measure the positions and germination rates of many thousands of individual spores and (ii) compute pairwise correlations of their germination. This analysis showed that an individual spore's germination rate was dependent on its distance from other spores, especially at short distances. Thus, spores that were within a few micrometers exhibited an increased synchronicity in germination, suggesting that there is a mechanism for short-range communication between such spores during germination. However, two molecules known to be germinants that are released during germination, l-alanine and the 1:1 chelate of Ca²⁺ and dipicolinic acid, did not mediate spore-to-spore communication during germination.
Collapse
|
48
|
Characterization of bacterial spore germination using phase-contrast and fluorescence microscopy, Raman spectroscopy and optical tweezers. Nat Protoc 2011; 6:625-39. [PMID: 21527920 DOI: 10.1038/nprot.2011.307] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This protocol describes a method combining phase-contrast and fluorescence microscopy, Raman spectroscopy and optical tweezers to characterize the germination of single bacterial spores. The characterization consists of the following steps: (i) loading heat-activated dormant spores into a temperature-controlled microscope sample holder containing a germinant solution plus a nucleic acid stain; (ii) capturing a single spore with optical tweezers; (iii) simultaneously measuring phase-contrast images, Raman spectra and fluorescence images of the optically captured spore at 2- to 10-s intervals; and (iv) analyzing the acquired data for the loss of spore refractility, changes in spore-specific molecules (in particular, dipicolinic acid) and uptake of the nucleic acid stain. This information leads to precise correlations between various germination events, and takes 1-2 h to complete. The method can also be adapted to use multi-trap Raman spectroscopy or phase-contrast microscopy of spores adhered on a cover slip to simultaneously obtain germination parameters for multiple individual spores.
Collapse
|
49
|
Bacterial spores in food: how phenotypic variability complicates prediction of spore properties and bacterial behavior. Curr Opin Biotechnol 2011; 22:180-6. [DOI: 10.1016/j.copbio.2010.11.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 11/12/2010] [Accepted: 11/15/2010] [Indexed: 11/21/2022]
|
50
|
Kinetics of germination of wet-heat-treated individual spores of Bacillus species, monitored by Raman spectroscopy and differential interference contrast microscopy. Appl Environ Microbiol 2011; 77:3368-79. [PMID: 21441336 DOI: 10.1128/aem.00046-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Raman spectroscopy and differential interference contrast (DIC) microscopy were used to monitor the kinetics of nutrient and nonnutrient germination of multiple individual untreated and wet-heat-treated spores of Bacillus cereus and Bacillus megaterium, as well as of several isogenic Bacillus subtilis strains. Major conclusions from this work were as follows. (i) More than 90% of these spores were nonculturable but retained their 1:1 chelate of Ca²+ and dipicolinic acid (CaDPA) when incubated in water at 80 to 95°C for 5 to 30 min. (ii) Wet-heat treatment significantly increased the time, T(lag), at which spores began release of the great majority of their CaDPA during the germination of B. subtilis spores with different nutrient germinants and also increased the variability of T(lag) values. (iii) The time period, ΔT(release), between T(lag) and the time, T(release), at which a spore germinating with nutrients completed the release of the great majority of its CaDPA, was also increased in wet-heat-treated spores. (iv) Wet-heat-treated spores germinating with nutrients had higher values of I(release), the intensity of a spore's DIC image at T(release), than did untreated spores and had much longer time periods, ΔT(lys), for the reduction in I(release) intensities to the basal value due to hydrolysis of the spore's peptidoglycan cortex, probably due at least in part to damage to the cortex-lytic enzyme CwlJ. (v) Increases in T(lag) and ΔT(release) were also observed when wet-heat-treated B. subtilis spores were germinated with the nonnutrient dodecylamine, while the change in I(release) was less significant. (vi) The effects of wet-heat treatment on nutrient germination of B. cereus and B. megaterium spores were generally similar to those on B. subtilis spores. These results indicate that (i) some proteins important in spore germination are damaged by wet-heat treatment, (ii) the cortex-lytic enzyme CwlJ is one germination protein damaged by wet heat, and (iii) the CaDPA release process itself seems likely to be the target of wet-heat damage which has the greatest effect on spore germination.
Collapse
|