1
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Yang W, Yuan Y, He L, Fan H. Single-cell analysis reveals microbial spore responses to sodium hypochlorite. JOURNAL OF BIOPHOTONICS 2024; 17:e202400015. [PMID: 38613161 DOI: 10.1002/jbio.202400015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/30/2024] [Accepted: 04/02/2024] [Indexed: 04/14/2024]
Abstract
Pollution from toxic spores has caused us a lot of problems because spores are extremely resistant and can survive most disinfectants. Therefore, the detection of spore response to disinfectant is of great significance for the development of effective decontamination strategies. In this work, we investigated the effect of 0.5% sodium hypochlorite on the molecular and morphological properties of single spores of Bacillus subtilis using single-cell techniques. Laser tweezers Raman spectroscopy showed that sodium hypochlorite resulted in Ca2+-dipicolinic acid release and nucleic acid denaturation. Atomic force microscopy showed that the surface of treated spores changed from rough to smooth, protein shells were degraded at 10 min, and the permeability barrier was destroyed at 15 min. The spore volume decreased gradually over time. Live-cell imaging showed that the germination and growth rates decreased with increasing treatment time. These results provide new insight into the response of spores to sodium hypochlorite.
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Affiliation(s)
- Weiming Yang
- School of Electrical Engineering and Intelligentization, Dongguan University of Technology, Dongguan, Guangdong, China
- School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou, Guangdong, China
| | - Yufeng Yuan
- School of Electrical Engineering and Intelligentization, Dongguan University of Technology, Dongguan, Guangdong, China
| | - Lin He
- School of Electrical Engineering and Intelligentization, Dongguan University of Technology, Dongguan, Guangdong, China
| | - Haihua Fan
- School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou, Guangdong, China
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2
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Öberg R, Sil TB, Ohlin A, Andersson M, Malyshev D. Assessing CaDPA levels, metabolic activity, and spore detection through deuterium labeling. Analyst 2024; 149:1861-1871. [PMID: 38348676 DOI: 10.1039/d3an02162a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Many strains among spore-forming bacteria species are associated with food spoilage, foodborne disease, and hospital-acquired infections. Understanding the impact of environmental conditions and decontamination techniques on the metabolic activity, viability, and biomarkers of these spores is crucial for combatting them. To distinguish and track spores and to understand metabolic mechanisms, spores must be labeled. Staining or genetic modification are current methods for this, however, these methods can be time-consuming, and affect the viability and function of spore samples. In this work, we investigate the use of heavy water for permanent isotope labeling of spores and Raman spectroscopy for tracking sporulation/germination mechanisms. We also discuss the potential of this method in observing decontamination. We find that steady-state deuterium levels in the spore are achieved after only ∼48 h of incubation with 30% D2O-infused broth and sporulation, generating Raman peaks at cell silent region of 2200 and 2300 cm-1. These deuterium levels then decrease rapidly upon spore germination in non-deuterated media. We further find that unlike live spores, spores inactivated using various methods do not lose these Raman peaks upon incubation in growth media, suggesting these peaks may be used to indicate the viability of a spore sample. We further observe several Raman peaks exclusive to deuterated DPA, a spore-specific chemical biomarker, at e.g. 988 and 2300 cm-1, which can be used to track underlying changes in spores involving DPA. In conclusion, permanent spore labeling using deuterium offers a robust and non-invasive way of labeling bacterial spores for marking, viability determination, and characterising spore activity.
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Affiliation(s)
- Rasmus Öberg
- Department of Physics, Umeå University, 901 87, Umeå, Sweden.
- Swedish Defence Research Agency (FOI), Cementvägen 20, 906 21 Umeå, Sweden
| | - Timir Baran Sil
- Department of Physics, Umeå University, 901 87, Umeå, Sweden.
| | - André Ohlin
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden
| | | | - Dmitry Malyshev
- Department of Physics, Umeå University, 901 87, Umeå, Sweden.
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3
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Öberg R, Sil TB, Johansson AC, Malyshev D, Landström L, Johansson S, Andersson M, Andersson PO. UV-Induced Spectral and Morphological Changes in Bacterial Spores for Inactivation Assessment. J Phys Chem B 2024; 128:1638-1646. [PMID: 38326108 PMCID: PMC10895659 DOI: 10.1021/acs.jpcb.3c07062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/09/2024]
Abstract
The ability to detect and inactivate spore-forming bacteria is of significance within, for example, industrial, healthcare, and defense sectors. Not only are stringent protocols necessary for the inactivation of spores but robust procedures are also required to detect viable spores after an inactivation assay to evaluate the procedure's success. UV radiation is a standard procedure to inactivate spores. However, there is limited understanding regarding its impact on spores' spectral and morphological characteristics. A further insight into these UV-induced changes can significantly improve the design of spore decontamination procedures and verification assays. This work investigates the spectral and morphological changes to Bacillus thuringiensis spores after UV exposure. Using absorbance and fluorescence spectroscopy, we observe an exponential decay in the spectral intensity of amino acids and protein structures, as well as a logistic increase in dimerized DPA with increased UV exposure on bulk spore suspensions. Additionally, using micro-Raman spectroscopy, we observe DPA release and protein degradation with increased UV exposure. More specifically, the protein backbone's 1600-1700 cm-1 amide I band decays slower than other amino acid-based structures. Last, using electron microscopy and light scattering measurements, we observe shriveling of the spore bodies with increased UV radiation, alongside the leaking of core content and disruption of proteinaceous coat and exosporium layers. Overall, this work utilized spectroscopy and electron microscopy techniques to gain new understanding of UV-induced spore inactivation relating to spore degradation and CaDPA release. The study also identified spectroscopic indicators that can be used to determine spore viability after inactivation. These findings have practical applications in the development of new spore decontamination and inactivation validation methods.
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Affiliation(s)
- Rasmus Öberg
- Swedish
Defence Research Agency (FOI), Umeå 90621, Sweden
- Department
of Physics, Umeå University, Umeå 90736, Sweden
| | - Timir B. Sil
- Department
of Physics, Umeå University, Umeå 90736, Sweden
| | | | | | - Lars Landström
- Swedish
Defence Research Agency (FOI), Norra Sorunda 13794, Sweden
| | | | - Magnus Andersson
- Department
of Physics, Umeå University, Umeå 90736, Sweden
- Umeå
Centre for Microbial Research (UCMR), Umeå 90736, Sweden
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4
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Coluccelli N, Cichelli G, Laporta P, Cerullo G. Single-shot detection of bacterial spores with Yb-laser-based CARS spectroscopy. OPTICS EXPRESS 2023; 31:23245-23259. [PMID: 37475414 DOI: 10.1364/oe.493869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/12/2023] [Indexed: 07/22/2023]
Abstract
We present a system based on a high-energy femtosecond ytterbium laser seeding an optical parametric amplifier and a photonic crystal hollow core fiber (PCHCF) compressor for coherent anti-Stokes Raman scattering (CARS) spectroscopy. The PCHCF provides spectral broadening of the Stokes pulse which is then compressed to a duration matched to that of the pump pulse. In these conditions, the excitation efficiency of vibrational levels in the target molecules is largely improved, as the time gating effect due to the mismatch between the durations of the pump and Stokes pulses is avoided. Experiments are presented along with a theoretical model to quantify expected improvement of sensitivity. The system is used to detect bacterial spores deposited on a surface with a single laser shot at unprecedented signal-to-noise ratio.
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5
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Nilsson DPG, Jonsmoen UL, Malyshev D, Öberg R, Wiklund K, Andersson M. Physico-chemical characterization of single bacteria and spores using optical tweezers. Res Microbiol 2023; 174:104060. [PMID: 37068697 DOI: 10.1016/j.resmic.2023.104060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 03/23/2023] [Accepted: 04/05/2023] [Indexed: 04/19/2023]
Abstract
Spore-forming pathogenic bacteria are adapted for adhering to surfaces, and their endospores can tolerate strong chemicals making decontamination difficult. Understanding the physico-chemical properties of bacteria and spores is therefore essential in developing antiadhesive surfaces and disinfection techniques. However, measuring physico-chemical properties in bulk does not show the heterogeneity between cells. Characterizing bacteria on a single-cell level can thereby provide mechanistic clues usually hidden in bulk measurements. This paper shows how optical tweezers can be applied to characterize single bacteria and spores, and how physico-chemical properties related to adhesion, fluid dynamics, biochemistry, and metabolic activity can be assessed.
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Affiliation(s)
| | - Unni Lise Jonsmoen
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 1433 Norway.
| | - Dmitry Malyshev
- Department of Physics, Umeå University, Västerbotten 901 87 Sweden.
| | - Rasmus Öberg
- Department of Physics, Umeå University, Västerbotten 901 87 Sweden.
| | - Krister Wiklund
- Department of Physics, Umeå University, Västerbotten 901 87 Sweden.
| | - Magnus Andersson
- Department of Physics, Umeå University, Västerbotten 901 87 Sweden; Umeå Center for Microbial Research (UCMR), 901 87 Sweden.
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6
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Tanaka K, Oketani R, Terada T, Leproux P, Morono Y, Kano H. Label-Free Identification of Spore-Forming Bacteria Using Ultrabroadband Multiplex Coherent Anti-Stokes Raman Scattering Microspectroscopy. J Phys Chem B 2023; 127:1940-1946. [PMID: 36821702 DOI: 10.1021/acs.jpcb.2c07291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Spore-forming bacteria accumulate dipicolinic acid (DPA) to form spores to survive in extreme environments. Vibrational spectroscopy is widely used to detect DPA and elucidate the existence of the bacteria, while vegetative cells, another form of spore-forming bacteria, have not been studied extensively. Herein, we applied coherent anti-Stokes Raman scattering (CARS) microscopy to spectroscopically identify both spores and vegetative cells without staining or molecular tagging. The spores were identified by the strong CARS signals due to DPA. Furthermore, we observed bright spots in the vegetative cells in the CARS image at 1735 cm-1. The vegetative cells contained molecular species with C=O bonds because this vibrational mode was associated with the carbonyl group. One of the candidate molecular species is diketopimelic acid (DKP), a DPA precursor. This hypothesis was verified by comparing the spectrum obtained by the vegetative cells with that of the DKP analogue (ketopimelic acid) and with the result obtained by DFT calculation. The results indicate that the observed vegetative cell is in the sporulation process. CARS spectra can be used to monitor the maturation and preformation of spores.
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Affiliation(s)
- Kyosuke Tanaka
- Department of Chemistry, Faculty of Science, Kyushu University, 744, Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Ryosuke Oketani
- Department of Chemistry, Faculty of Science, Kyushu University, 744, Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Takeshi Terada
- Marine Works Japan, 3-54-1 Oppamahigashi, Yokosuka, Kanagawa 237-0063, Japan
| | - Philippe Leproux
- Institut de Recherche XLIM, UMR CNRS No. 7252, 123 Avenue Albert Thomas, 87060 Limoges CEDEX, France
| | - Yuki Morono
- Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 200 Monobe Otsu, Nankoku City, Kochi 783-8502, Japan
| | - Hideaki Kano
- Department of Chemistry, Faculty of Science, Kyushu University, 744, Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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7
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Malyshev D, Jones IA, McKracken M, Öberg R, Harper GM, Joshi LT, Andersson M. Hypervirulent R20291 Clostridioides difficile spores show disinfection resilience to sodium hypochlorite despite structural changes. BMC Microbiol 2023; 23:59. [PMID: 36879193 PMCID: PMC9986864 DOI: 10.1186/s12866-023-02787-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 02/06/2023] [Indexed: 03/08/2023] Open
Abstract
BACKGROUND Clostridioides difficile is a spore forming bacterial species and the major causative agent of nosocomial gastrointestinal infections. C. difficile spores are highly resilient to disinfection methods and to prevent infection, common cleaning protocols use sodium hypochlorite solutions to decontaminate hospital surfaces and equipment. However, there is a balance between minimising the use of harmful chemicals to the environment and patients as well as the need to eliminate spores, which can have varying resistance properties between strains. In this work, we employ TEM imaging and Raman spectroscopy to analyse changes in spore physiology in response to sodium hypochlorite. We characterize different C. difficile clinical isolates and assess the chemical's impact on spores' biochemical composition. Changes in the biochemical composition can, in turn, change spores' vibrational spectroscopic fingerprints, which can impact the possibility of detecting spores in a hospital using Raman based methods. RESULTS We found that the isolates show significantly different susceptibility to hypochlorite, with the R20291 strain, in particular, showing less than 1 log reduction in viability for a 0.5% hypochlorite treatment, far below typically reported values for C. difficile. While TEM and Raman spectra analysis of hypochlorite-treated spores revealed that some hypochlorite-exposed spores remained intact and not distinguishable from controls, most spores showed structural changes. These changes were prominent in B. thuringiensis spores than C. difficile spores. CONCLUSION This study highlights the ability of certain C. difficile spores to survive practical disinfection exposure and the related changes in spore Raman spectra that can be seen after exposure. These findings are important to consider when designing practical disinfection protocols and vibrational-based detection methods to avoid a false-positive response when screening decontaminated areas.
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Affiliation(s)
| | | | | | - Rasmus Öberg
- Department of Physics, Umeå University, Umeå, Sweden
| | | | | | - Magnus Andersson
- Department of Physics, Umeå University, Umeå, Sweden. .,Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden.
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8
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Valijam S, Nilsson DP, Öberg R, Albertsdóttir Jonsmoen UL, Porch A, Andersson M, Malyshev D. A lab-on-a-chip utilizing microwaves for bacterial spore disruption and detection. Biosens Bioelectron 2023; 231:115284. [PMID: 37031508 DOI: 10.1016/j.bios.2023.115284] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/07/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
Bacterial spores are problematic in agriculture, the food industry, and healthcare, with the fallout costs from spore-related contamination being very high. Spores are difficult to detect since they are resistant to many of the bacterial disruption techniques used to bring out the biomarkers necessary for detection. Because of this, effective and practical spore disruption methods are desirable. In this study, we demonstrate the efficiency of a compact microfluidic lab-on-chip built around a coplanar waveguide (CPW) operating at 2.45 GHz. We show that the CPW generates an electric field hotspot of ∼10 kV/m, comparable to that of a commercial microwave oven, while using only 1.2 W of input power and thus resulting in negligible sample heating. Spores passing through the microfluidic channel are disrupted by the electric field and release calcium dipicolinic acid (CaDPA), a biomarker molecule present alongside DNA in the spore core. We show that it is possible to detect this disruption in a bulk spore suspension using fluorescence spectroscopy. We then use laser tweezers Raman spectroscopy (LTRS) to show the loss of CaDPA on an individual spore level and that the loss increases with irradiation power. Only 22% of the spores contain CaDPA after exposure to 1.2 W input power, compared to 71% of the untreated control spores. Additionally, spores exposed to microwaves appear visibly disrupted when imaged using scanning electron microscopy (SEM). Overall, this study shows the advantages of using a CPW for disrupting spores for biomarker release and detection.
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9
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Standoff detection of bacterial spores by field deployable coherent Raman spectroscopy. Sci Rep 2023; 13:2634. [PMID: 36788326 PMCID: PMC9929236 DOI: 10.1038/s41598-023-29589-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/07/2023] [Indexed: 02/16/2023] Open
Abstract
Vibrational spectroscopies offer great potential for standoff detection of chemical and biological warfare agents, avoiding contamination to the operator and equipment. Among them, particularly promising is Coherent anti-Stokes Raman scattering (CARS) spectroscopy, using synchronized pump/Stokes laser pulses to set up a vibrational coherence of target molecules at a laser focus, which is read by further interaction with a probe pulse, resulting in the emission of a coherent beam detectable at a distance. CARS has previously demonstrated the capability to detect bacterial spores based on the Raman spectrum of the characteristic molecule calcium dipicolinate (CaDPA); however, a complex and bulky laser technology, which is only suitable for a laboratory environment, was employed. Here we develop a broadband CARS setup based on a compact, industrial grade ytterbium laser system. We demonstrate high signal-to-noise ratio detection of Bacillus atrophaeus spores at a concentration of 105 cfu/mm2, at a standoff distance of 1 m, and an acquisition time of 1 s. Our system, which combines chemical specificity and sensitivity along with improved ruggedness and portability, paves the way to a new generation of instruments for real-world standoff detection of chemical and biological threats.
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10
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Pacheco M, Dikec J, Winckler P, Coelho C, Perrier-Cornet JM. Spectroscopic and microscopic characterization of dipicolinic acid and its salt photoproducts - A UVc effect study on DPA in solution and in bacterial spores. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 280:121502. [PMID: 35752036 DOI: 10.1016/j.saa.2022.121502] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/10/2022] [Accepted: 06/12/2022] [Indexed: 06/15/2023]
Abstract
Bacterial spores can cause significant problems such as food poisoning (like neurotoxin or emetic toxin) or serious illnesses (like anthrax or botulism). This dormant form of bacteria, made of several layers of barriers which provide extreme resistance to many abiotic stresses (radiation, temperature, pressure, etc.), are difficult to investigate in situ. To better understand the biological and chemical mechanisms involved and specific to spores resistance, the acquisition of environmental parameters is necessary. For that purpose, our research has been focused on the detection and analysis of a unique spore component, dipicolinic acid (DPA), used as the main in situ metabolite for sporulating bacteria detection. In its native form, DPA is only weakly fluorescent but after Ultraviolet irradiation at the wavelength of 254 nm (UVc), DPA photoproducts (DPAp) exhibit a remarkable fluorescence signal. These photoproducts are rarely identified and part of this study gives new insights offered by mass spectrometry (MS) in the determination of DPA photoproducts. Thanks to DPA assay techniques and fluorescence spectrometry, we highlighted the instability of photoproducts and introduced new assumptions on the effects of UVc on DPA. Studies in spectroscopy and microscopy allowed us to better understand these native probes in bacterial spores and will allow the implementation of a new method for studying the physico-chemical parameters of spore resistance.
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Affiliation(s)
- Maxime Pacheco
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - Jonathan Dikec
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - Pascale Winckler
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France
| | - Christian Coelho
- Université Clermont Auvergne, INRAE, VetAgro Sup campus agronomique de Lempdes, UMR F, 15000 Aurillac, France
| | - Jean-Marie Perrier-Cornet
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France.
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11
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Dikec J, Pacheco M, Lavaud M, Winckler P, Perrier-Cornet JM. Uptake of UVc induced photoproducts of dipicolinic acid by Bacillus subtilis spores - Effects on the germination and UVc resistance of the spores. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 236:112569. [PMID: 36152351 DOI: 10.1016/j.jphotobiol.2022.112569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/05/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
Dipicolinic acid (DPA) is a specific molecule of bacterial spores which is essential to their resistance to various stresses such as ultraviolet (UV) exposure and to their germination. DPA has a particular photochemistry that remains imperfectly understood. In particular, due to its ability to absorb UVc radiation, it is likely to form in vitro a wide variety of photoproducts (DPAp) of which only about ten have been recently identified. The photochemical reactions resulting in DPAp, especially those inside the spores, are still poorly understood. Only one of these DPAp, which probably acts as a photosensitizer of DNA upon exposure to UVc, has been identified as having an impact on spores. However, as UVc is required to form DPAp, it is difficult to decouple the overall effect of UVc exposure from the possible effects of DPAp alone. In this study, DPAp were artificially introduced into the spores of the FB122 mutant strain of Bacillus subtilis, one that does not produce DPA. These experiments revealed that some DPAp may play a positive role for the spore. These benefits are visible in an improvement in spore germination rate and kinetics, as well as in an increase in their resistance to UVc exposure.
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Affiliation(s)
- J Dikec
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - M Pacheco
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - M Lavaud
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France
| | - P Winckler
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France
| | - J M Perrier-Cornet
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France.
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12
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Dikec J, Bechoua N, Winckler P, Perrier-Cornet JM. Effects of pulsed near infrared light (NIR) on Bacillus subtilis spores. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 234:112530. [PMID: 35930949 DOI: 10.1016/j.jphotobiol.2022.112530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/13/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
In this study, we develop a characterization of bacterial spore resistance to NIR pulsed light under modalities traditionally used in multiphoton microscopy. Energy dose and laser power are both key parameters in spore and bacterial cell inactivation. Surprisingly, spores and vegetative cells seem to show a similar sensitivity to pulsed NIR, spores being only 2-fold more resistant than their vegetative counterparts. This work enables us to eliminate certain hypotheses concerning the main driver of spore inactivation processes. Our findings suggest that damage leading to inactivation is mainly caused by photochemical reactions characterized by multiple possible pathways, including DNA damage or oxidation processes.
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Affiliation(s)
- J Dikec
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - N Bechoua
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - P Winckler
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France
| | - J M Perrier-Cornet
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France.
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13
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A ratiometric fluorescent nanoprobe based on ZIF-8@AuNCs–Tb for visual detection of 2,6-pyridinedicarboxylic acid. J RARE EARTH 2022. [DOI: 10.1016/j.jre.2021.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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Wu T. A Raman optical activity spectrometer can sensitively detect lanthanide circularly polarized luminescence. Phys Chem Chem Phys 2022; 24:15672-15686. [PMID: 35735101 DOI: 10.1039/d2cp01641a] [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
Recently, many studies have appeared in which the Raman optical activity (ROA) instrument was found to be convenient for measuring circularly polarized luminescence (CPL). Typically, weak lanthanide luminescence including circular polarization could be detected. The new detection scheme is referred to as ROA-CPL spectroscopy. It is particularly useful when also the vibrational (ROA) itself is detectable as the molecule structure can be examined more reliably. In this review, development of this chiroptical approach and its applications in structural studies of biomolecules are summarized.
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Affiliation(s)
- Tao Wu
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo náměstí 2, 16610, Prague, Czech Republic.
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15
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Discrimination of Stressed and Non-Stressed Food-Related Bacteria Using Raman-Microspectroscopy. Foods 2022; 11:foods11101506. [PMID: 35627076 PMCID: PMC9141442 DOI: 10.3390/foods11101506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/16/2022] [Accepted: 05/19/2022] [Indexed: 01/27/2023] Open
Abstract
As the identification of microorganisms becomes more significant in industry, so does the utilization of microspectroscopy and the development of effective chemometric models for data analysis and classification. Since only microorganisms cultivated under laboratory conditions can be identified, but they are exposed to a variety of stress factors, such as temperature differences, there is a demand for a method that can take these stress factors and the associated reactions of the bacteria into account. Therefore, bacterial stress reactions to lifetime conditions (regular treatment, 25 °C, HCl, 2-propanol, NaOH) and sampling conditions (cold sampling, desiccation, heat drying) were induced to explore the effects on Raman spectra in order to improve the chemometric models. As a result, in this study nine food-relevant bacteria were exposed to seven stress conditions in addition to routine cultivation as a control. Spectral alterations in lipids, polysaccharides, nucleic acids, and proteins were observed when compared to normal growth circumstances without stresses. Regardless of the involvement of several stress factors and storage times, a model for differentiating the analyzed microorganisms from genus down to strain level was developed. Classification of the independent training dataset at genus and species level for Escherichia coli and at strain level for the other food relevant microorganisms showed a classification rate of 97.6%.
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16
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Malyshev D, Öberg R, Landström L, Andersson PO, Dahlberg T, Andersson M. pH-induced changes in Raman, UV-vis absorbance, and fluorescence spectra of dipicolinic acid (DPA). SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 271:120869. [PMID: 35065519 DOI: 10.1016/j.saa.2022.120869] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 11/29/2021] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
Dipicolinic acid (DPA) is an essential component for the protection of DNA in bacterial endospores and is often used as a biomarker for spore detection. Depending upon the pH of the solution, DPA exists in different ionic forms. Therefore, it is important to understand how these ionic forms influence spectroscopic response. In this work, we characterize Raman and absorption spectra of DPA in a pH range of 2.0-10.5. We show that the ring breathing mode Raman peak of DPA shifts from 1003 cm-1 to 1017 cm-1 and then to 1000 cm-1 as pH increases from 2 to 5. The relative peak intensities related to the different ionic forms of DPA are used to experimentally derive the pKa values (2.3 and 4.8). We observe using UV-vis spectroscopy that the changes in the absorption spectrum of DPA as a function of pH correlate with the changes observed in Raman spectroscopy, and the same pKa values are verified. Lastly, using fluorescence spectroscopy and exciting a DPA solution at between 210-330 nm, we observe a shift in fluorescence emission from 375 nm to 425 nm between pH 2 and pH 6 when exciting at 320 nm. Our work shows that the different spectral responses from the three ionic forms of DPA may have to be taken into account in, e.g., spectral analysis and for detection applications.
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Affiliation(s)
| | - Rasmus Öberg
- Dept of Physics, Umeå University, 901 87 Umeå, Sweden
| | | | - Per Ola Andersson
- Swedish Defence Research Agency (FOI), Umeå, Sweden; Department of Engineering Sciences, Uppsala University, Uppsala, Sweden
| | | | - Magnus Andersson
- Dept of Physics, Umeå University, 901 87 Umeå, Sweden; Umeå Centre for Microbial Research (UCMR), Umeå, Sweden.
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17
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Malyshev D, Öberg R, Dahlberg T, Wiklund K, Landström L, Andersson PO, Andersson M. Laser induced degradation of bacterial spores during micro-Raman spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 265:120381. [PMID: 34562861 DOI: 10.1016/j.saa.2021.120381] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 08/09/2021] [Accepted: 09/06/2021] [Indexed: 06/13/2023]
Abstract
Micro-Raman spectroscopy combined with optical tweezers is a powerful method to analyze how the biochemical composition and molecular structures of individual biological objects change with time. In this work we investigate laser induced effects in the trapped object. Bacillus thuringiensis spores, which are robust organisms known for their resilience to light, heat, and chemicals are used for this study. We trap spores and monitor the Raman peak from CaDPA (calcium dipicolinic acid), which is a chemical protecting the spore core. We see a correlation between the amount of laser power used in the trap and the release of CaDPA from the spore. At a laser power of 5 mW, the CaDPA from spores in water suspension remain intact over the 90 min experiment, however, at higher laser powers an induced effect could be observed. SEM images of laser exposed spores (after loss of CaDPA Raman peak was confirmed) show a notable alteration of the spores' structure. Our Raman data indicates that the median dose exposure to lose the CaDPA peak was ∼60 J at 808 nm. For decontaminated/deactivated spores, i.e., treated in sodium hypochlorite or peracetic acid solutions, the sensitivity on laser power is even more pronounced and different behavior could be observed on spores treated by the two chemicals. Importantly, the observed effect is most likely photochemical since the increase of the spore temperature is in the order of 0.1 K as suggested by our numerical multiphysics model. Our results show that care must be taken when using micro-Raman spectroscopy on biological objects since photoinduced effects may substantially affect the results.
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Affiliation(s)
| | - Rasmus Öberg
- Dept of Physics, Umeå University, 901 87 Umeå, Sweden
| | | | | | | | - Per Ola Andersson
- Swedish Defence Research Agency (FOI), Umeå, Sweden; Department of Engineering Sciences, Uppsala University, Uppsala, Sweden
| | - Magnus Andersson
- Dept of Physics, Umeå University, 901 87 Umeå, Sweden; Umeå Centre for Microbial Research (UCMR), Umeå, Sweden.
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18
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Nguyen MCT, Nguyen HQ, Jang H, Noh S, Lee SY, Jang KS, Lee J, Sohn Y, Yee K, Jung H, Kim J. Sterilization effects of UV laser irradiation on Bacillus atrophaeus spore viability, structure, and proteins. Analyst 2021; 146:7682-7692. [PMID: 34812439 DOI: 10.1039/d1an01717a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Bacillus spores are highly resistant to toxic chemicals and extreme environments. Because some Bacillus species threaten public health, spore inactivation techniques have been intensively investigated. We exposed Bacillus atrophaeus spores to a 266 nm Nd:YVO4 laser at a laser power of 1 W and various numbers of scans. As a result, the UV laser reduced the viability of Bacillus atrophaeus spores. Although the outer coat of spores remained intact after UV laser irradiation of 720 scans, damage inside the spores was observed. Spore proteins were identified by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry during the course of UV laser irradiation. Photochemical and photothermal processes are believed to be involved in the UV laser sterilization of Bacillus spores. Our findings suggest that a UV laser is capable of sterilizing Bacillus atrophaeus spores.
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Affiliation(s)
- My-Chi Thi Nguyen
- Department of Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Huu-Quang Nguyen
- Department of Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Hanbyeol Jang
- Department of Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Sojung Noh
- Department of Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Seong-Yeon Lee
- Department of Physics and Institute of Quantum Systems, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Kyoung-Soon Jang
- Biomedical Omics Center, Korea Basic Science Institute, Cheongju, Republic of Korea
| | - Jaebeom Lee
- Department of Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea.,Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Youngku Sohn
- Department of Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea.,Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Kiju Yee
- Department of Physics and Institute of Quantum Systems, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Heesoo Jung
- Chem-Bio Technology Center, Agency for Defense Development (ADD), Yuseong P.O. Box 35, Daejeon, 34186, Republic of Korea.
| | - Jeongkwon Kim
- Department of Chemistry, Chungnam National University, Daejeon, 34134, Republic of Korea.,Graduate School of New Drug Discovery and Development, Chungnam National University, Daejeon, Republic of Korea.
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19
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Ultraviolet-C inactivation and hydrophobicity of Bacillus subtilis and Bacillus velezensis spores isolated from extended shelf-life milk. Int J Food Microbiol 2021; 349:109231. [PMID: 34022614 DOI: 10.1016/j.ijfoodmicro.2021.109231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 03/31/2021] [Accepted: 04/25/2021] [Indexed: 11/23/2022]
Abstract
Bacterial spores are important in food processing due to their ubiquity, resistance to high temperature and chemical inactivation. This work aims to study the effect of ultraviolet C (UVC) on the spores of Bacillus subtilis and Bacillus velezensis at a molecular and individual level to guide in deciding on the right parameters that must be applied during the processing of liquid foods. The spores were treated with UVC using phosphate buffer saline (PBS) as a suspension medium and their lethality rate was determined for each sample. Purified spore samples of B. velezensis and B. subtilis were treated under one pass in a UVC reactor to inactivate the spores. The resistance pattern of the spores to UVC treatment was determined using dipicolinic acid (Ca-DPA) band of spectral analysis obtained from Raman spectroscopy. Flow cytometry analysis was also done to determine the effect of the UVC treatment on the spore samples at the molecular level. Samples were processed for SEM and the percentage spore surface hydrophobicity was also determined using the Microbial Adhesion to Hydrocarbon (MATH) assay to predict the adhesion strength to a stainless-steel surface. The result shows the maximum lethality rate to be 6.5 for B. subtilis strain SRCM103689 (B47) and highest percentage hydrophobicity was 54.9% from the sample B. velezensis strain LPL-K103 (B44). The difference in surface hydrophobicity for all isolates was statistically significant (P < 0.05). Flow cytometry analysis of UVC treated spore suspensions clarifies them further into sub-populations unaccounted for by plate counting on growth media. The Raman spectroscopy identified B4002 as the isolate possessing the highest concentration of Ca-DPA. The study justifies the critical role of Ca-DPA in spore resistance and the possible sub-populations after UVC treatment that may affect product shelf-life and safety. UVC shows a promising application in the inactivation of resistant spores though there is a need to understand the effects at the molecular level to design the best parameters during processing.
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20
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Ryu Y, Hong M, Kim SB, Lee TK, Park W. Raman spectroscopy reveals alteration of spore compositions under different nutritional conditions in Lysinibacillus boronitolerans YS11. J Microbiol 2021; 59:491-499. [PMID: 33779962 DOI: 10.1007/s12275-021-0679-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/28/2021] [Accepted: 02/08/2021] [Indexed: 01/01/2023]
Abstract
Little is known about final spores components when bacteria undergo sporulation under different nutrient conditions. Different degrees of resistance and germination rates were observed in the three types of spores of Lysinibacillus boronitolerans YS11 (SD, Spores formed in Difco sporulation medium™; SC and SF, Spores formed in an agricultural byproduct medium with 10 mM CaCl2 and with 10 mM FeSO4, respectively). Stronger UV resistance was recorded for SF with 1.8-2.3-fold greater survival than SC and SD under UV treatment. The three spore types showed similar heat resistances at 80°C, but survival rates of SC and SD were much higher (∼1,000 times) than those of SF at 90°C. However, germination capacity of SF was 20% higher than those of SD and SC on Luria-Bertani agar plates for 24 h. SF germinated more rapidly in a liquid medium with high NaCl concentrations than SC and SD, but became slower under alkaline conditions. Raman spectroscopy was used to analyze the heterogeneities in the three types of vegetative cells and their spores under different nutritional conditions. Exponentially grown-each vegetative cells had different overall Raman peak values. Raman peaks of SC, SD, and SF also showed differences in adenine and amide III compositions and nucleic acid contents. Our data along with Raman spectroscopy provided the evidence that spores formed under under different growth conditions possess very different cellular components, which affected their survival and germination rates.
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Affiliation(s)
- Youngung Ryu
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Minyoung Hong
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Soo Bin Kim
- Department of Environmental Engineering, Yonsei University, Wonju, 26493, Republic of Korea
| | - Tae Kwon Lee
- Department of Environmental Engineering, Yonsei University, Wonju, 26493, Republic of Korea
| | - Woojun Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
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21
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Camerlingo C, Di Meo G, Lepore M, Lisitskiy M, Poli A, Portaccio M, Romano I, Di Donato P. Graphene-Based and Surface-Enhanced Raman Spectroscopy for Monitoring the Physio-Chemical Response of Thermophilic Bacterial Spores to Low Temperatures Exposure. SENSORS 2020; 20:s20154150. [PMID: 32722541 PMCID: PMC7435614 DOI: 10.3390/s20154150] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/18/2020] [Accepted: 07/22/2020] [Indexed: 12/25/2022]
Abstract
Monitoring the spore life cycle is one of the main issues in several fields including environmental control, sustainable ecosystems, food security, and healthcare systems. In this framework, the study of the living organism resistance to extreme conditions like those mimicking space environments is particularly interesting. The assessment of the local change of the pH level can be extremely useful for this purpose. An optical physiometer method based on the Raman response of the graphene, which is able to locally sense pH of a fluid on a micrometric scale, has been recently proposed. Due to the presence of π-bonds at the surface, the electronic doping of graphene is determined by the external conditions and can be electrochemically controlled or altered by the contact with an acid or alkaline fluid. The doping level affects the vibrational energies of the graphene that can be monitored by conventional Raman spectroscopy. In addition, Surface-Enhanced Raman Spectroscopy (SERS) can give direct information on the biochemical changes occurring in spore components. In this work, we propose the joint use of Graphene-Based Raman Spectroscopy (GbRS) and SERS for the monitoring of the response of spores to exposure to low temperatures down to 100 K. The spores of the thermophilic bacterium Parageobacillus thermantarcticus isolated from an active volcano of Antarctica (Mt. Melbourne) were investigated. These spores are particularly resistant to several stressing stimuli and able to adapt to extreme conditions like low temperatures, UV irradiation, and γ-rays exposure. The results obtained showed that the joint use of GbRS and SERS represents a valuable tool for monitoring the physio-chemical response of bacterial spores upon exposure to stressing stimuli.
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Affiliation(s)
- Carlo Camerlingo
- CNR-SPIN, Institute for Superconductivity, Innovative Materials and Devices, 80078 Pozzuoli, Italy; (C.C.); (M.L.)
| | - Giuseppe Di Meo
- CNR-ICB, Institute of Biomolecular Chemistry, 80078 Pozzuoli, Italy; (G.D.M.); (A.P.); (I.R.); (P.D.D.)
| | - Maria Lepore
- Dipartimento di Medicina Sperimentale, Università della Campania “L. Vanvitelli”, Via S. Maria di Costantinopoli 16, 80138 Napoli, Italy;
- Correspondence:
| | - Mikhail Lisitskiy
- CNR-SPIN, Institute for Superconductivity, Innovative Materials and Devices, 80078 Pozzuoli, Italy; (C.C.); (M.L.)
| | - Annarita Poli
- CNR-ICB, Institute of Biomolecular Chemistry, 80078 Pozzuoli, Italy; (G.D.M.); (A.P.); (I.R.); (P.D.D.)
| | - Marianna Portaccio
- Dipartimento di Medicina Sperimentale, Università della Campania “L. Vanvitelli”, Via S. Maria di Costantinopoli 16, 80138 Napoli, Italy;
| | - Ida Romano
- CNR-ICB, Institute of Biomolecular Chemistry, 80078 Pozzuoli, Italy; (G.D.M.); (A.P.); (I.R.); (P.D.D.)
| | - Paola Di Donato
- CNR-ICB, Institute of Biomolecular Chemistry, 80078 Pozzuoli, Italy; (G.D.M.); (A.P.); (I.R.); (P.D.D.)
- Dipartimento di Scienze e Tecnologie, Università Parthenope di Napoli, Centro Direzionale Isola C/4, 80143 Napoli, Italy
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22
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The molecular dynamics of bacterial spore and the role of calcium dipicolinate in core properties at the sub-nanosecond time-scale. Sci Rep 2020; 10:8265. [PMID: 32427943 PMCID: PMC7237433 DOI: 10.1038/s41598-020-65093-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/21/2020] [Indexed: 11/18/2022] Open
Abstract
Bacterial spores are among the most resistant forms of life on Earth. Their exceptional resistance properties rely on various strategies, among them the core singular structure, organization and hydration. By using elastic incoherent neutron scattering, we probed the dynamics of Bacillus subtilis spores to determine whether core macromolecular motions at the sub-nanosecond timescale could also contribute to their resistance to physical stresses. In addition, in order to better specify the role of the various spore components, we used different mutants lacking essential structure such as the coat (PS4150 mutant), or the calcium dipicolinic acid complex (CaDPA) located in the core (FB122 mutant). PS4150 allows to better probe the core’s dynamics, as proteins of the coat represent an important part of spore proteins, and FB122 gives information about the role of the large CaDPA depot for the mobility of core’s components. We show that core’s macromolecular mobility is not particularly constrained at the sub-nanosecond timescale in spite of its low water content as some dynamical characteristics as force constants are very close to those of vegetative bacteria such as Escherichia coli or to those of fully hydrated proteins. Although the force constants of the coatless mutant are similar to the wild-type’s ones, it has lower mean square displacements (MSDs) at high Q showing that core macromolecules are somewhat more constrained than the rest of spore components. However, no behavior reflecting the glassy state regularly evoked in the literature could be drawn from our data. As hydration and macromolecules’ mobility are highly correlated, the previous assumption, that core low water content might explain spores’ exceptional resistance properties seems unlikely. Thus, we confirm recent theories, suggesting that core water is mostly as free as bulk water and proteins/macromolecules are fully hydrated. The germination of spores leads to a much less stable system with a force constant of 0.1 N/m and MSDs ~2.5 times higher at low Q than in the dormant state. DPA has also an influence on core mobility with a slightly lower force constant for the DPA-less mutant than for the wild-type, and MSDs that are ~ 1.8 times higher on average than for the wild-type at low Q. At high Q, germinated and DPA-less spores were very similar to the wild-type ones, showing that DPA and core compact structure might influence large amplitude motions rather than local dynamics of macromolecules.
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23
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Senthilnathan N, Gaurav K, Venkata Ramana C, Radhakrishnan TP. Zwitterionic small molecule based fluorophores for efficient and selective imaging of bacterial endospores. J Mater Chem B 2020; 8:4601-4608. [PMID: 32391841 DOI: 10.1039/d0tb00470g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In the emerging scenario of increasing antibiotic resistance and pathogen transmission channels, the grave danger posed by bacterial endospores in critical fields like food industry, health and medicine highlights the urgent need to develop efficient probes for their detection; their sturdy and impermeable multilayer coat makes desirable methods like fluorescence imaging extremely difficult. Selective imaging of the endospores in the presence of the bacteria is even more challenging. Furthermore, it is preferable to maintain the dormant state of endospores through the imaging process, if extended monitoring is required; many of the available techniques involve lethal germination or destruction of the endospores. We show that simple zwitterionic diaminodicyanoquinodimethane (DADQ) molecules with selected functionalities are efficient dyes for fluorescence imaging due to their dipolar structure that facilitates the penetration into the endospore system, and the enhanced fluorescence in their rigid/aggregated state. The facile structural tailorability allows DADQs with various appendage moieties to be synthesized; a derivative with ionic substituents (BT2), and another with optimally long alkyl chains and the resultant hydrophobic character (BHADQ) are shown to be excellent fluorescent probes for endospores. Nanomolar amounts of dyes provide effective staining; while BT2 stains bacteria and endospores, most significantly, BHADQ stains endospores selectively. To the best of our knowledge, this is the first example of selective fluorescence imaging of endospores in their dormant state. A range of spectroscopy, microscopy and calorimetry studies provide insight into the molecular level interactions that enable efficient staining and bright images. DADQ fluorophores are photostable and non-cytotoxic, hence useful in practical applications. The versatile structural tailorability of these dye molecules holds great promise for targeted imaging.
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Affiliation(s)
- N Senthilnathan
- School of Chemistry, University of Hyderabad, Hyderabad - 500 046, India.
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24
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Highly accurate classification of biological spores by culture medium for forensic attribution using multiple chemical signature types and machine learning. Anal Bioanal Chem 2020; 412:4287-4299. [PMID: 32328690 DOI: 10.1007/s00216-020-02660-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/01/2020] [Accepted: 04/14/2020] [Indexed: 01/29/2023]
Abstract
Future proliferation of biological expertise and new technology may increasingly lower the difficulty to produce biological organisms for misuse. Rapid attribution of a biological attack is needed to quickly identify the person or lab responsible and prevent additional attacks by enabling the apprehension of suspects. Here, triplicate batches of Bacillus anthracis Sterne strain (BaSt) spores were grown in a total of seven amateur and professional media. Multiple orthogonal analytical signatures (peptides, metabolites, lipids by fatty acid methyl ester (FAME) analysis, bulk organic profile, and trace elements) were collected from the BaSt spores. The proteomics and metabolomics analyses identified promising attribution signature compounds that are unique to each of the seven production methods. In addition, while each of the signature types showed varying degrees of value individually for attributing BaSt spores to the culture medium used to prepare them, fusing results from all five signatures types to increase sourcing robustness and using a random forest sourcing algorithm yielded 100% hold-one-batch-out cross-validation classification accuracy and an average relative source probability for the correct source 5.5× higher than the most probable incorrect source. These preliminary results provide a proof-of-concept for the development of forensic examinations that can attribute biological agents to production methods for use in future investigations.
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25
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Dong W, Setlow P. Fluoride movement into and out of Bacillus spores and growing cells and effects of fluoride accumulation on spore properties. J Appl Microbiol 2018; 126:503-515. [PMID: 30430725 DOI: 10.1111/jam.14155] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/04/2018] [Accepted: 11/05/2018] [Indexed: 12/25/2022]
Abstract
AIMS To investigate effects of fluoride ion (F- ) on, and kinetics of its movement into and out of, spores and growing cells of Bacillus species. METHODS AND RESULTS Effects of F- on Bacillus cell growth, spore germination and outgrowth and heat resistance were investigated, as well as F- movement into and out of spores using 19 F-NMR. F- inhibited Bacillus subtilis spore germination and outgrowth, and YhdU, now named FluC, was crucial to prevent F- accumulation in growing cells and to minimize F- inhibition of spore germination. Dormant wild-type, yhdU and coat defective B. subtilis spores, and Bacillus cereus spores incubated in 40 mmol l-1 NaF for 48 h accumulated 2-2·6 mol l-1 F- and its movement into Bacillus spores was highest at low pH. Bacillus subtilis spores lacking Ca-dipicolinic acid accumulated higher F- levels than wild-type spores. CONCLUSIONS These results are consistent with F- incorporation into the dormant spore core, and as HF and/or NaF, but not CaF2 . YhdU played no significant role in F- uptake or efflux in dormant spores, but assisted in F- export early in spore germination. SIGNIFICANCE AND IMPACT OF STUDY This knowledge provides new insight into effects of F- on Bacillus cells and spores and how this anion moves into, and out of spores.
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Affiliation(s)
- W Dong
- School of Resource and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou, China.,Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
| | - P Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
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26
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Single-cell analysis reveals individual spore responses to simulated space vacuum. NPJ Microgravity 2018; 4:26. [PMID: 30534587 PMCID: PMC6279783 DOI: 10.1038/s41526-018-0059-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 10/23/2018] [Indexed: 02/07/2023] Open
Abstract
Outer space is a challenging environment for all forms of life, and dormant spores of bacteria have been frequently used to study the survival of terrestrial life in a space journey. Previous work showed that outer space vacuum alone can kill bacterial spores. However, the responses and mechanisms of resistance of individual spores to space vacuum are unclear. Here, we examined spores’ molecular changes under simulated space vacuum (~10−5 Pa) using micro-Raman spectroscopy and found that this vacuum did not cause significant denaturation of spore protein. Then, live-cell microscopy was developed to investigate the temporal events during germination, outgrowth, and growth of individual Bacillus spores. The results showed that after exposure to simulated space vacuum for 10 days, viability of spores of two Bacillus species was reduced up to 35%, but all spores retained their large Ca2+-dipicolinic acid depot. Some of the killed spores did not germinate, and the remaining germinated but did not proceed to vegetative growth. The vacuum treatment slowed spore germination, and changed average times of all major germination events. In addition, viable vacuum-treated spores exhibited much greater sensitivity than untreated spores to dry heat and hyperosmotic stress. Among spores’ resistance mechanisms to high vacuum, DNA-protective α/β−type small acid-soluble proteins, and non-homologous end joining and base excision repair of DNA played the most important roles, especially against multiple cycles of vacuum treatment. Overall, these results give new insight into individual spore’s responses to space vacuum and provide new techniques for microorganism analysis at the single-cell level.
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Resistance and Raman spectroscopy analysis of Parageobacillus thermantarcticus spores after γ-ray exposure. Extremophiles 2018; 22:931-941. [PMID: 30120597 DOI: 10.1007/s00792-018-1049-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/08/2018] [Indexed: 01/17/2023]
Abstract
Spores of the genus Bacillus are able to resist ionizing radiations and therefore they are a suitable biological model for studies in Astrobiology, i.e. the multidisciplinary approach to the study of the origin and evolution of life on Earth and in the universe. The resistance to γ-radiation is an important issue in Astrobiology in relation to the search for bacterial species that could adapt to life in space. This study investigates the resistance of spores of the thermophilic bacteria Parageobacillus thermantarcticus to γ-rays. The analysis of spores' response to irradiation at a molecular level is performed by means of Raman spectroscopy that allows to get insights in the sequence of events taking place during inactivation. The role of the γ-rays' dose in the inactivation of spores is also investigated, allowing to highlight the mechanism(s) of inactivation including DNA damage, protein denaturation and calcium dipicolinate levels.
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Germination, Outgrowth, and Vegetative-Growth Kinetics of Dry-Heat-Treated Individual Spores of Bacillus Species. Appl Environ Microbiol 2018; 84:AEM.02618-17. [PMID: 29330188 DOI: 10.1128/aem.02618-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 01/08/2018] [Indexed: 11/20/2022] Open
Abstract
DNA damage kills dry-heated spores of Bacillus subtilis, but dry-heat-treatment effects on spore germination and outgrowth have not been studied. This is important, since if dry-heat-killed spores germinate and undergo outgrowth, toxic proteins could be synthesized. Here, Raman spectroscopy and differential interference contrast microscopy were used to study germination and outgrowth of individual dry-heat-treated B. subtilis and Bacillus megaterium spores. The major findings in this work were as follows: (i) spores dry-heat-treated at 140°C for 20 min lost nearly all viability but retained their Ca2+-dipicolinic acid (CaDPA) depot; (ii) in most cases, dry-heat treatment increased the average times and variability of all major germination events in B. subtilis spore germination with nutrient germinants or CaDPA, and in one nutrient germination event with B. megaterium spores; (iii) B. subtilis spore germination with dodecylamine, which activates the spore CaDPA release channel, was unaffected by dry-heat treatment; (iv) these results indicate that dry-heat treatment likely damages spore proteins important in nutrient germinant recognition and cortex peptidoglycan hydrolysis, but not CaDPA release itself; and (v) analysis of single spores incubated on nutrient-rich agar showed that while dry-heat-treated spores that are dead can complete germination, they cannot proceed into outgrowth and thus not to vegetative growth. The results of this study provide new information on the effects of dry heat on bacterial spores and indicate that dry-heat sterilization regimens should produce spores that cannot outgrow and thus cannot synthesize potentially dangerous proteins.IMPORTANCE Much research has shown that high-temperature dry heat is a promising means for the inactivation of spores on medical devices and spacecraft decontamination. Dry heat is known to kill Bacillus subtilis spores by DNA damage. However, knowledge about the effects of dry-heat treatment on spore germination and outgrowth is limited, especially at the single spore level. In the current work, Raman spectroscopy and differential interference contrast microscopy were used to analyze CaDPA levels in and kinetics of nutrient- and non-nutrient germination of multiple individual dry-heat-treated B. subtilis and Bacillus megaterium spores that were largely dead. The outgrowth and subsequent cell division of these germinated but dead dry-heat-treated spores were also examined. The knowledge obtained in this study will help understand the effects of dry heat on spores both on Earth and in space, and indicates that dry heat can be safely used for sterilization purposes.
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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.
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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
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30
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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.
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31
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Wu T, Kapitán J, Andrushchenko V, Bouř P. Identification of Lanthanide(III) Luminophores in Magnetic Circularly Polarized Luminescence Using Raman Optical Activity Instrumentation. Anal Chem 2017; 89:5043-5049. [DOI: 10.1021/acs.analchem.7b00435] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Tao Wu
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo
náměstí 2, 16610 Prague 6, Czech Republic
| | - Josef Kapitán
- Department
of Optics, Palacký University, 17. listopadu 12, 77146 Olomouc, Czech Republic
| | - Valery Andrushchenko
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo
náměstí 2, 16610 Prague 6, Czech Republic
| | - Petr Bouř
- Institute
of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo
náměstí 2, 16610 Prague 6, Czech Republic
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32
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Rao L, Liao X, Setlow P. Bacillus spore wet heat resistance and evidence for the role of an expanded osmoregulatory spore cortex. Lett Appl Microbiol 2016; 63:247-53. [PMID: 27424522 DOI: 10.1111/lam.12615] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 07/11/2016] [Accepted: 07/12/2016] [Indexed: 11/28/2022]
Abstract
UNLABELLED Previous work reported that decoated Bacillus cereus spores incubated in 4 mol l(-1) CaCl2 are killed at lower temperatures than spores in water. This wet heat sensitization was suggested to support a role for an osmoregulatory peptidoglycan cortex in spore cores' low water content, and their wet heat resistance. Current work has replicated this finding with spores of B. cereus, Bacillus megaterium and Bacillus subtilis. However, this work found that decoated spores apparently killed at 80°C in 4 mol l(-1) CaCl2 : (i) were recovered on plates containing lysozyme; (ii) lost no dipicolinic acid (DPA) and their inner membrane remained impermeable; (iii) released no DPA upon stimulation with nutrient germinants and could not complete germination; and (iv) released DPA relatively normally upon stimulation with dodecylamine. These results indicate that decoated spores treated with 80°C- 4 mol l(-1) CaCl2 are not dead, but some protein(s) essential for spore germination, most likely germinant receptors, are inactivated by this treatment. Thus, the original finding does not support a role for an osmoregulatory cortex in spore wet heat resistance. SIGNIFICANCE AND IMPACT OF THE STUDY Bacillus spores' low core water content is a major factor in their wet heat resistance. One suggested mechanism for achieving low spore core water content is osmoregulated expansion of spores' peptidoglycan cortex. Evidence for this mechanism includes a report that decoated Bacillus cereus spores incubated in 4 mol l(-1) CaCl2 exhibit drastically reduced heat resistance. The current work shows that this heat sensitization of decoated spores of three Bacillus species is most likely due to inactivation of some crucial spore germination protein(s), since while treated spores appear dead, their apparent low viability is rescued by triggering spore germination with lysozyme.
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Affiliation(s)
- L Rao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,National Engineering Research Center for Fruit and Vegetable Processing, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture, Beijing, China.,Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
| | - X Liao
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.,National Engineering Research Center for Fruit and Vegetable Processing, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture, Beijing, China
| | - P Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA.
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33
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Wu T, Kessler J, Bouř P. Chiral sensing of amino acids and proteins chelating with EuIII complexes by Raman optical activity spectroscopy. Phys Chem Chem Phys 2016; 18:23803-11. [DOI: 10.1039/c6cp03968e] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chiroptical spectroscopy of lanthanides sensitively reflects their environment and finds various applications including probing protein structures.
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Affiliation(s)
- Tao Wu
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences
- 16610 Prague 6
- Czech Republic
| | - Jiří Kessler
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences
- 16610 Prague 6
- Czech Republic
| | - Petr Bouř
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences
- 16610 Prague 6
- Czech Republic
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34
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Setlow P, Li L. Photochemistry and Photobiology of the Spore Photoproduct: A 50-Year Journey. Photochem Photobiol 2015; 91:1263-90. [PMID: 26265564 PMCID: PMC4631623 DOI: 10.1111/php.12506] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 07/21/2015] [Indexed: 02/06/2023]
Abstract
Fifty years ago, a new thymine dimer was discovered as the dominant DNA photolesion in UV-irradiated bacterial spores [Donnellan, J. E. & Setlow R. B. (1965) Science, 149, 308-310], which was later named the spore photoproduct (SP). Formation of SP is due to the unique environment in the spore core that features low hydration levels favoring an A-DNA conformation, high levels of calcium dipicolinate that acts as a photosensitizer, and DNA saturation with small, acid-soluble proteins that alters DNA structure and reduces side reactions. In vitro studies reveal that any of these factors alone can promote SP formation; however, SP formation is usually accompanied by the production of other DNA photolesions. Therefore, the nearly exclusive SP formation in spores is due to the combined effects of these three factors. Spore photoproduct photoreaction is proved to occur via a unique H-atom transfer mechanism between the two involved thymine residues. Successful incorporation of SP into an oligonucleotide has been achieved via organic synthesis, which enables structural studies that reveal minor conformational changes in the SP-containing DNA. Here, we review the progress on SP photochemistry and photobiology in the past 50 years, which indicates a very rich SP photobiology that may exist beyond endospores.
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Affiliation(s)
- Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, Indiana, 46202
- Department of Biochemistry and Molecular Biology & Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana 46202
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35
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Friedline AW, Zachariah MM, Middaugh AN, Garimella R, Vaishampayan PA, Rice CV. Sterilization Resistance of Bacterial Spores Explained with Water Chemistry. J Phys Chem B 2015; 119:14033-44. [DOI: 10.1021/acs.jpcb.5b07437] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anthony W. Friedline
- Department of Chemistry and Biochemistry, Stephenson
Life Sciences Research Center, University of Oklahoma, 101 Stephenson
Parkway, Norman, Oklahoma 73019, United States
| | - Malcolm M. Zachariah
- Department of Chemistry and Biochemistry, Stephenson
Life Sciences Research Center, University of Oklahoma, 101 Stephenson
Parkway, Norman, Oklahoma 73019, United States
| | - Amy N. Middaugh
- Department of Chemistry and Biochemistry, Stephenson
Life Sciences Research Center, University of Oklahoma, 101 Stephenson
Parkway, Norman, Oklahoma 73019, United States
| | - Ravindranath Garimella
- Department of Chemistry and Biochemistry, Stephenson
Life Sciences Research Center, University of Oklahoma, 101 Stephenson
Parkway, Norman, Oklahoma 73019, United States
| | - Parag A. Vaishampayan
- Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, M/S 89-108, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Charles V. Rice
- Department of Chemistry and Biochemistry, Stephenson
Life Sciences Research Center, University of Oklahoma, 101 Stephenson
Parkway, Norman, Oklahoma 73019, United States
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36
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Noue ACDL, Peters J, Gervais P, Martinez N, Perrier-Cornet JM, Natali F. Proton dynamics in bacterial spores, a neutron scattering investigation. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158302003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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37
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Friedline AW, Zachariah MM, Johnson K, Thomas KJ, Middaugh AN, Garimella R, Powell DR, Vaishampayan PA, Rice CV. Water behavior in bacterial spores by deuterium NMR spectroscopy. J Phys Chem B 2014; 118:8945-55. [PMID: 24950158 PMCID: PMC4216197 DOI: 10.1021/jp5025119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Dormant bacterial spores are able
to survive long periods of time
without nutrients, withstand harsh environmental conditions, and germinate
into metabolically active bacteria when conditions are favorable.
Numerous factors influence this hardiness, including the spore structure
and the presence of compounds to protect DNA from damage. It is known
that the water content of the spore core plays a role in resistance
to degradation, but the exact state of water inside the core is a
subject of discussion. Two main theories present themselves: either
the water in the spore core is mostly immobile and the core and its
components are in a glassy state, or the core is a gel with mobile
water around components which themselves have limited mobility. Using
deuterium solid-state NMR experiments, we examine the nature of the
water in the spore core. Our data show the presence of unbound water,
bound water, and deuterated biomolecules that also contain labile
deuterons. Deuterium–hydrogen exchange experiments show that
most of these deuterons are inaccessible by external water. We believe
that these unreachable deuterons are in a chemical bonding state that
prevents exchange. Variable-temperature NMR results suggest that the
spore core is more rigid than would be expected for a gel-like state.
However, our rigid core interpretation may only apply to dried spores
whereas a gel core may exist in aqueous suspension. Nonetheless, the
gel core, if present, is inaccessible to external water.
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Affiliation(s)
- Anthony W Friedline
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma , 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
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38
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Analysis of the loss in heat and acid resistance during germination of spores of Bacillus species. J Bacteriol 2014; 196:1733-40. [PMID: 24563034 DOI: 10.1128/jb.01555-14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A major event in the nutrient germination of spores of Bacillus species is release of the spores' large depot of dipicolinic acid (DPA). This event is preceded by both commitment, in which spores continue through germination even if germinants are removed, and loss of spore heat resistance. The latter event is puzzling, since spore heat resistance is due largely to core water content, which does not change until DPA is released during germination. We now find that for spores of two Bacillus species, the early loss in heat resistance during germination is most likely due to release of committed spores' DPA at temperatures not lethal for dormant spores. Loss in spore acid resistance during germination also paralleled commitment and was also associated with the release of DPA from committed spores at acid concentrations not lethal for dormant spores. These observations plus previous findings that DPA release during germination is preceded by a significant release of spore core cations suggest that there is a significant change in spore inner membrane permeability at commitment. Presumably, this altered membrane cannot retain DPA during heat or acid treatments innocuous for dormant spores, resulting in DPA-less spores that are rapidly killed.
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39
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Kong L, Setlow P, Li YQ. Direct analysis of water content and movement in single dormant bacterial spores using confocal Raman microspectroscopy and Raman imaging. Anal Chem 2013; 85:7094-101. [PMID: 23815288 DOI: 10.1021/ac400516p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Heavy water (D2O) has a distinct molecular vibration spectrum, and this has been used to analyze the water content, distribution, and movement in single dormant Bacillus cereus spores using confocal Raman microspectroscopy and Raman imaging. These methods have been used to measure the kinetics of D2O release from spores suspended in H2O, the spatial distribution of D2O in spores, and the kinetics of D2O release from spores during dehydration in air at room temperature. The results obtained were as follows. (1) The Raman spectrum of single D2O-loaded dormant spores suggests that D2O in spores is in a relatively weak hydrogen-bonded mode, compared to the strong hydrogen-bonded mode in pure D2O. (2) The D2O content of individual spores in a population was somewhat heterogeneous. (3) The spatial distribution of D2O in single dormant spores is uneven, and is less dense in the central core region. Raman images of different molecular components indicate that the water distribution is somewhat different from those of proteins and Ca-dipicolinic acid. (4) Exchange of spore D2O with external H2O took place in less than 1 s. (5) However, release of spore D2O during air dehydration at room temperature was slow and heterogeneous and took 2-3 h for complete D2O release.
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Affiliation(s)
- Lingbo Kong
- Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353, United States
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