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El-Gendy AO, Ezzat S, Samad FA, Dabbous OA, Dahm J, Hamblin MR, Mohamed T. Studying the viability and growth kinetics of vancomycin-resistant Enterococcus faecalis V583 following femtosecond laser irradiation (420-465 nm). Lasers Med Sci 2024; 39:144. [PMID: 38809462 PMCID: PMC11136855 DOI: 10.1007/s10103-024-04080-5] [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: 01/02/2024] [Accepted: 05/12/2024] [Indexed: 05/30/2024]
Abstract
Enterococcus faecalis is among the most resistant bacteria found in infected root canals. The demand for cutting-edge disinfection methods has rekindled research on photoinactivation with visible light. This study investigated the bactericidal activity of femtosecond laser irradiation against vancomycin-resistant Enterococcus faecalis V583 (VRE). The effect of parameters such as wavelength and energy density on the viability and growth kinetics of VRE was studied to design an optimized laser-based antimicrobial photoinactivation approach without any prior addition of exogenous photosensitizers. The most effective wavelengths were 430 nm and 435 nm at a fluence of 1000 J/cm2, causing a nearly 2-log reduction (98.6% and 98.3% inhibition, respectively) in viable bacterial counts. The colony-forming units and growth rate of the laser-treated cultures were progressively decreased as energy density or light dose increased at 445 nm but reached a limit at 1250 J/cm2. At a higher fluence of 2000 J/cm2, the efficacy was reduced due to a photobleaching phenomenon. Our results highlight the importance of optimizing laser exposure parameters, such as wavelength and fluence, in bacterial photoinactivation experiments. To our knowledge, this is the first study to report an optimized wavelength for the inactivation of VRE using visible femtosecond laser light.
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Affiliation(s)
- Ahmed O El-Gendy
- Laser Institute for Research and Applications LIRA, Beni-Suef University, Beni-Suef, 62511, Egypt
- Department of Microbiology and Immunology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef, 62514, Egypt
| | - Sarah Ezzat
- Department of Microbiology and Immunology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef, 62514, Egypt
| | - Fatma Abdel Samad
- Department of Microbiology and Immunology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef, 62514, Egypt
| | - Ola Ali Dabbous
- Department of Medical Applications of Lasers, National Institute of Laser Enhanced Science (NILES), Cairo University, Giza, 12611, Egypt
| | | | - Michael R Hamblin
- Laser Research Centre, Faculty of Health Science, University of Johannesburg, Doornfontein, 2028, South Africa
| | - Tarek Mohamed
- Laser Institute for Research and Applications LIRA, Beni-Suef University, Beni-Suef, 62511, Egypt.
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Liang N, Mohamed H, Pung RF, Waite-Cusic J, Dallas DC. Optimized Ultraviolet-C Processing Inactivates Pathogenic and Spoilage-Associated Bacteria while Preserving Bioactive Proteins, Vitamins, and Lipids in Human Milk. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:12198-12208. [PMID: 38752986 DOI: 10.1021/acs.jafc.4c02120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Holder pasteurization (HoP) enhances donor human milk microbiological safety but damages many bioactive milk proteins. Though ultraviolet-C irradiation (UV-C) can enhance safety while better preserving some milk proteins, it has not been optimized for dose or effect on a larger array of bioactive proteins. We determined the minimal UV-C parameters that provide >5-log reductions of relevant bacteria in human milk and how these treatments affect an array of bioactive proteins, vitamin E, and lipid oxidation. Treatment at 6000 and 12 000 J/L of UV-C resulted in >5-log reductions of all vegetative bacteria and bacterial spores, respectively. Both dosages improved retention of immunoglobulin A (IgA), IgG, IgM, lactoferrin, cathepsin D, and elastase and activities of bile-salt-stimulated lipase and lysozyme compared with HoP. These UV-C doses caused minor reductions in α-tocopherol but not γ-tocopherol and no increases in lipid oxidation products. UV-C treatment is a promising approach for donor human milk processing.
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Affiliation(s)
- Ningjian Liang
- Nutrition Program, College of Health, Oregon State University, Corvallis, Oregon 97331, United States
| | - Hussein Mohamed
- Department of Food Science and Technology, Oregon State University, Corvallis, Oregon 97331, United States
| | - Rachel F Pung
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
| | - Joy Waite-Cusic
- Department of Food Science and Technology, Oregon State University, Corvallis, Oregon 97331, United States
| | - David C Dallas
- Nutrition Program, College of Health, Oregon State University, Corvallis, Oregon 97331, United States
- Department of Food Science and Technology, Oregon State University, Corvallis, Oregon 97331, United States
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Muratov E, Rosenbaum FP, Fuchs FM, Ulrich NJ, Awakowicz P, Setlow P, Moeller R. Multifactorial resistance of Bacillus subtilis spores to low-pressure plasma sterilization. Appl Environ Microbiol 2024; 90:e0132923. [PMID: 38112445 PMCID: PMC10807416 DOI: 10.1128/aem.01329-23] [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: 08/04/2023] [Accepted: 11/05/2023] [Indexed: 12/21/2023] Open
Abstract
Common sterilization techniques for labile and sensitive materials have far-reaching applications in medical, pharmaceutical, and industrial fields. Heat inactivation, chemical treatment, and radiation are established methods to inactivate microorganisms, but pose a threat to humans and the environment and can damage susceptible materials or products. Recent studies have demonstrated that cold low-pressure plasma (LPP) treatment is an efficient alternative to common sterilization methods, as LPP's levels of radicals, ions, (V)UV-radiation, and exposure to an electromagnetic field can be modulated using different process gases, such as oxygen, nitrogen, argon, or synthetic (ambient) air. To further investigate the effects of LPP, spores of the Gram-positive model organism Bacillus subtilis were tested for their LPP susceptibility including wild-type spores and isogenic spores lacking DNA-repair mechanisms such as non-homologous end-joining (NHEJ) or abasic endonucleases, and protective proteins like α/β-type small acid-soluble spore proteins (SASP), coat proteins, and catalase. These studies aimed to learn how spores resist LPP damage by examining the roles of key spore proteins and DNA-repair mechanisms. As expected, LPP treatment decreased spore survival, and survival after potential DNA damage generated by LPP involved efficient DNA repair following spore germination, spore DNA protection by α/β-type SASP, and catalase breakdown of hydrogen peroxide that can generate oxygen radicals. Depending on the LPP composition and treatment time, LPP treatment offers another method to efficiently inactivate spore-forming bacteria.IMPORTANCESurface-associated contamination by endospore-forming bacteria poses a major challenge in sterilization, since the omnipresence of these highly resistant spores throughout nature makes contamination unavoidable, especially in unprocessed foods. Common bactericidal agents such as heat, UV and γ radiation, and toxic chemicals such as strong oxidizers: (i) are often not sufficient to completely inactivate spores; (ii) can pose risks to the applicant; or (iii) can cause unintended damage to the materials to be sterilized. Cold low-pressure plasma (LPP) has been proposed as an additional method for spore eradication. However, efficient use of LPP in decontamination requires understanding of spores' mechanisms of resistance to and protection against LPP.
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Affiliation(s)
- Erika Muratov
- Radiation Biology Department, Aerospace Microbiology, Institute of Aerospace Medicine, German Aerospace Center (DLR e.V.), Cologne, Germany
| | - Florian P. Rosenbaum
- Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt, Germany
| | - Felix M. Fuchs
- Applied Electrodynamics and Plasma Technology, Biomedical Applications of Plasma Technology, Ruhr University Bochum, Bochum, Germany
| | - Nikea J. Ulrich
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Peter Awakowicz
- Applied Electrodynamics and Plasma Technology, Biomedical Applications of Plasma Technology, Ruhr University Bochum, Bochum, Germany
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Ralf Moeller
- Radiation Biology Department, Aerospace Microbiology, Institute of Aerospace Medicine, German Aerospace Center (DLR e.V.), Cologne, Germany
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Kadowaki R, Tanno H, Maeno S, Endo A. Spore-forming properties and enhanced oxygen tolerance of butyrate-producing Anaerostipes spp. Anaerobe 2023; 82:102752. [PMID: 37301503 DOI: 10.1016/j.anaerobe.2023.102752] [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: 04/20/2023] [Revised: 05/25/2023] [Accepted: 06/06/2023] [Indexed: 06/12/2023]
Abstract
OBJECTIVES Butyrate producing bacteria are promising candidates for next-generation probiotics. However, they are extremely sensitive to oxygen, which is a significant obstacle to their inclusion in food matrices in a viable form. The present study characterized the spore-forming properties and stress tolerance of human gut butyrate-producing Anaerostipes spp. METHODS Spore formation properties in six species of Anaerostipes spp. were studied by in vitro and in silico tests. RESULTS Spores were observed from the cells of three species using microscopic analyses, while the remaining three did not form spores under the tested conditions. Spore-forming properties were confirmed by an ethanol treatment. The spores of Anaerostipes caccae were tolerant to oxygen and survived for 15 weeks under atmospheric conditions. Spores tolerated heat stress at 70 °C, but not at 80 °C. An in silico analysis of the conservation of potential sporulation signature genes revealed that the majority of human gut butyrate-producing bacteria were classified as potential spore formers. Comparative genomics revealed that three spore-forming Anaerostipes spp. specifically possessed the spore formation-related genes of bkdR, sodA, and splB, which may be key genes for different sporulation properties in Anaerostipes spp. CONCLUSIONS The present study demonstrated the enhanced stress tolerance of butyrate producing Anaerostipes spp. for future probiotic application. Presence of specific gene(s) are possibly keys for sporulation in Anaerostipes spp.
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Affiliation(s)
- Ren Kadowaki
- Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bioindustry, Tokyo University of Agriculture, 099-2493, Hokkaido, Japan
| | - Hiroki Tanno
- Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bioindustry, Tokyo University of Agriculture, 099-2493, Hokkaido, Japan
| | - Shintaro Maeno
- Graduate School of Medical Sciences, Kyushu University, 812-8582, Fukuoka, Japan
| | - Akihito Endo
- Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bioindustry, Tokyo University of Agriculture, 099-2493, Hokkaido, Japan; Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 156-8502, Tokyo, Japan.
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Setlow P, Christie G. New Thoughts on an Old Topic: Secrets of Bacterial Spore Resistance Slowly Being Revealed. Microbiol Mol Biol Rev 2023; 87:e0008022. [PMID: 36927044 PMCID: PMC10304885 DOI: 10.1128/mmbr.00080-22] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
Abstract
The quest for bacterial survival is exemplified by spores formed by some Firmicutes members. They turn up everywhere one looks, and their ubiquity reflects adaptations to the stresses bacteria face. Spores are impactful in public health, food safety, and biowarfare. Heat resistance is the hallmark of spores and is countered principally by a mineralized gel-like protoplast, termed the spore core, with reduced water which minimizes macromolecular movement/denaturation/aggregation. Dry heat, however, introduces mutations into spore DNA. Spores have countermeasures to extreme conditions that are multifactorial, but the fact that spore DNA is in a crystalline-like nucleoid in the spore core, likely due to DNA saturation with small acid-soluble spore proteins (SASPs), suggests that reduced macromolecular motion is also critical in spore dry heat resistance. SASPs are also central in the radiation resistance characteristic of spores, where the contributions of four spore features-SASP; Ca2+, with pyridine-2,6-dicarboxylic acid (CaDPA); photoproduct lyase; and low water content-minimize DNA damage. Notably, the spore environment steers UV photochemistry toward a product that germinated spores can repair without significant mutagenesis. This resistance extends to chemicals and macromolecules that could damage spores. Macromolecules are excluded by the spore coat which impedes the passage of moieties of ≥10 kDa. Additionally, damaging chemicals may be degraded or neutralized by coat enzymes/proteins. However, the principal protective mechanism here is the inner membrane, a compressed structure lacking lipid fluidity and presenting a barrier to the diffusion of chemicals into the spore core; SASP saturation of DNA also protects against genotoxic chemicals. Spores are also resistant to other stresses, including high pressure and abrasion. Regardless, overarching mechanisms associated with resistance seem to revolve around reduced molecular motion, a fine balance between rigidity and flexibility, and perhaps efficient repair.
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Affiliation(s)
- Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Graham Christie
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom
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Thery T, Beney L, Grangeteau C, Dupont S. Sporicidal efficiency of an ultra-high irradiance (UHI) near UV/visible light treatment: An example of application to infected mandarins. Food Control 2023. [DOI: 10.1016/j.foodcont.2022.109568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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7
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Amodeo D, Lucarelli V, De Palma I, Puccio A, Nante N, Cevenini G, Messina G. Efficacy of violet-blue light to inactive microbial growth. Sci Rep 2022; 12:20179. [PMID: 36424450 PMCID: PMC9691702 DOI: 10.1038/s41598-022-24563-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 11/17/2022] [Indexed: 11/26/2022] Open
Abstract
The increase in health care-associated infections and antibiotic resistance has led to a growing interest in the search for innovative technologies to solve these problems. In recent years, the interest of the scientific community has focused on violet-blue light at 405 nm (VBL405). This study aimed to assess the VBL405 efficiency in reducing microbial growth on surfaces and air. This descriptive study run between July and October 2020. Petri dishes were contaminated with P. aeruginosa, E. coli, S. aureus, S. typhimurium, K. pneumoniae and were placed at 2 and 3 m from a LED light source having a wavelength peak at 405 nm and an irradiance respectively of 967 and 497 µW/cm2. Simultaneously, the air in the room was sampled for 5 days with two air samplers (SAS) before and after the exposition to the VBL405 source. The highest microbial reduction was reached 2 m directly under the light source: S. typhimurium (2.93 log10), K. pneumoniae (2.30 log10), S. aureus (3.98 log10), E. coli (3.83 log10), P. aeruginosa (3.86 log10). At a distance of 3 m from the light source, the greatest reduction was observed for S. aureus (3.49 log10), and P. aeruginosa (3.80 log10). An average percent microbial reduction of about 70% was found in the sampled air after 12 h of exposure to VBL405. VBL405 has proven to contrast microbial growth on the plates. Implementing this technology in the environment to provide continuous disinfection and to control microbial presence, even in the presence of people, may be an innovative solution.
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Affiliation(s)
- Davide Amodeo
- grid.9024.f0000 0004 1757 4641Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Valentina Lucarelli
- grid.9024.f0000 0004 1757 4641Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Isa De Palma
- grid.9024.f0000 0004 1757 4641Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Alessandro Puccio
- grid.9024.f0000 0004 1757 4641Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Nicola Nante
- grid.9024.f0000 0004 1757 4641Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Gabriele Cevenini
- grid.9024.f0000 0004 1757 4641Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Gabriele Messina
- grid.9024.f0000 0004 1757 4641Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
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Malyshev D, Robinson NF, Öberg R, Dahlberg T, Andersson M. Reactive oxygen species generated by infrared laser light in optical tweezers inhibits the germination of bacterial spores. JOURNAL OF BIOPHOTONICS 2022; 15:e202200081. [PMID: 35538633 DOI: 10.1002/jbio.202200081] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/28/2022] [Accepted: 05/08/2022] [Indexed: 06/14/2023]
Abstract
Bacterial spores are highly resistant to heat, radiation and various disinfection chemicals. The impact of these on the biophysical and physicochemical properties of spores can be studied on the single-cell level using optical tweezers. However, the effect of the trapping laser on spores' germination rate is not fully understood. In this work, we assess the impact of 1064 nm laser light on the germination of Bacillus thuringiensis spores. The results show that the germination rate of spores after laser exposure follows a sigmoid dose-response relationship, with only 15% of spores germinating after 20 J of laser light. Under anaerobic growth conditions, the percentage of germinating spores at 20 J increased to 65%. The results thereby indicate that molecular oxygen is a major contributor to the germination-inhibiting effect observed. Thus, our study highlights the risk for optical trapping of spores and ways to mitigate it.
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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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Yu X, Zheng P, Zou Y, Ye Z, Wei T, Lin J, Guo L, Yuk HG, Zheng Q. A review on recent advances in LED-based non-thermal technique for food safety: current applications and future trends. Crit Rev Food Sci Nutr 2022; 63:7692-7707. [PMID: 35369810 DOI: 10.1080/10408398.2022.2049201] [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: 11/03/2022]
Abstract
Light-emitting diodes (LEDs) is an eco-friendly light source with broad-spectrum antimicrobial activity. Recent studies have extensively been conducted to evaluate its efficacy in microbiological safety and the potential as a preservation method to extend the shelf-life of foods. This review aims to present the latest update of recent studies on the basics (physical, biochemical and mechanical basics) and antimicrobial activity of LEDs, as well as its application in the food industry. The highlight will be focused on the effects of LEDs on different types (bacteria, yeast/molds, viruses) and forms (planktonic cells, biofilms, endospores, fungal toxin) of microorganisms. The antimicrobial activity of LEDs on various food matrices was also evaluated, together with further analysis on the food-related factors that lead to the differences in LEDs efficiency. Besides, the applications of LEDs on the food-related conditions, packaged food, and equipment that could enhance LEDs efficiency were discussed to explore the future trends of LEDs technology in the food industry. Overall, the present review provides important insights for future research and the application of LEDs in the food industry.
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Affiliation(s)
- Xinpeng Yu
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Peng Zheng
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Yuan Zou
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Zhiwei Ye
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Tao Wei
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Junfang Lin
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Liqiong Guo
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Hyun-Gyun Yuk
- Department of Food Science and Technology, Korea National University of Transportation, Chungbuk, Republic of Korea
| | - Qianwang Zheng
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
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Small Prokaryotic DNA-Binding Proteins Protect Genome Integrity throughout the Life Cycle. Int J Mol Sci 2022; 23:ijms23074008. [PMID: 35409369 PMCID: PMC8999374 DOI: 10.3390/ijms23074008] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 03/27/2022] [Accepted: 04/01/2022] [Indexed: 12/17/2022] Open
Abstract
Genomes of all organisms are persistently threatened by endogenous and exogenous assaults. Bacterial mechanisms of genome maintenance must provide protection throughout the physiologically distinct phases of the life cycle. Spore-forming bacteria must also maintain genome integrity within the dormant endospore. The nucleoid-associated proteins (NAPs) influence nucleoid organization and may alter DNA topology to protect DNA or to alter gene expression patterns. NAPs are characteristically multifunctional; nevertheless, Dps, HU and CbpA are most strongly associated with DNA protection. Archaea display great variety in genome organization and many inhabit extreme environments. As of yet, only MC1, an archaeal NAP, has been shown to protect DNA against thermal denaturation and radiolysis. ssDNA are intermediates in vital cellular processes, such as DNA replication and recombination. Single-stranded binding proteins (SSBs) prevent the formation of secondary structures but also protect the hypersensitive ssDNA against chemical and nuclease degradation. Ionizing radiation upregulates SSBs in the extremophile Deinococcus radiodurans.
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Bauer R, Hoenes K, Meurle T, Hessling M, Spellerberg B. The effects of violet and blue light irradiation on ESKAPE pathogens and human cells in presence of cell culture media. Sci Rep 2021; 11:24473. [PMID: 34963696 PMCID: PMC8714816 DOI: 10.1038/s41598-021-04202-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 12/16/2021] [Indexed: 12/18/2022] Open
Abstract
Bacteria belonging to the group of ESKAPE pathogens are responsible for the majority of nosocomial infections. Due to the increase of antibiotic resistance, alternative treatment strategies are of high clinical relevance. In this context visible light as disinfection technique represents an interesting option as microbial pathogens can be inactivated without adjuvants. However cytotoxic effects of visible light on host cells have also been reported. We compared the cytotoxicity of violet and blue light irradiation on monocytic THP-1 and alveolar epithelium A549 cells with the inactivation effect on ESKAPE pathogens. THP-1 cells displayed a higher susceptibility to irradiation than A549 cells with first cytotoxic effects occurring at 300 J cm−2 (405 nm) and 400 J cm−2 (450 nm) in comparison to 300 J cm−2 and 1000 J cm−2, respectively. We could define conditions in which a significant reduction of colony forming units for all ESKAPE pathogens, except Enterococcus faecium, was achieved at 405 nm while avoiding cytotoxicity. Irradiation at 450 nm demonstrated a more variable effect which was species and medium dependent. In summary a significant reduction of viable bacteria could be achieved at subtoxic irradiation doses, supporting a potential use of visible light as an antimicrobial agent in clinical settings.
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Affiliation(s)
- Richard Bauer
- Institute of Medical Microbiology and Hygiene, University Hospital Ulm, 89081, Ulm, Germany
| | - Katharina Hoenes
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, 89081, Ulm, Germany
| | - Tobias Meurle
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, 89081, Ulm, Germany
| | - Martin Hessling
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, 89081, Ulm, Germany
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University Hospital Ulm, 89081, Ulm, Germany.
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12
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Lv R, Liu D, Wang W, Xu E, Ding T, Ye X, Zhou J. Proteomic response and molecular regulatory mechanisms of Bacillus cereus spores under ultrasound treatment. ULTRASONICS SONOCHEMISTRY 2021; 78:105732. [PMID: 34474268 PMCID: PMC8411229 DOI: 10.1016/j.ultsonch.2021.105732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 08/03/2021] [Accepted: 08/17/2021] [Indexed: 05/03/2023]
Abstract
This study was aimed at providing new insights on the proteomic response of bacterial spores to ultrasound. Data-independent-acquisition method was used to quantify the proteome change of Bacillus cereus spores after ultrasound treatment (200 W). This study revealed that 2485 proteins were extracted from Bacillus cereus spores, most of them were related to metabolism. After ultrasound treatment, the expression of 340 proteins were significantly changed (the fold change ≥ 2 and p < 0.05), of which 207 proteins were significantly down-regulated. KEGG pathway analysis showed that differentially expressed proteins mainly distributed in metabolism pathway, cell process pathway and genetic information processing pathway after ultrasound treatment. Furthermore, this study analyzed the differentially expressed proteins in significant enrichment pathways. In particular, the expression of key proteins in the phosphorylation reaction of spores was significantly decreased after ultrasound treatment. Thus, ATP synthesis rate decreased and the phosphorylation reaction inhibited. Also, the decrease of the expression of key proteins related to the tricarboxylic acid cycle led to the decrease of nutrients metabolism of spores. Ultrasound treatment induced the down-regulation of fatty acid synthetase expression and promoted fatty acid metabolism at the same time. The content of fatty acids decreased in spores consequently.
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Affiliation(s)
- Ruiling Lv
- NingboTech University, Ningbo 315100, China; Ningbo Research Institute, Zhejiang University, Ningbo 315100, China; College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou 310058, China
| | - Donghong Liu
- Ningbo Research Institute, Zhejiang University, Ningbo 315100, China; College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou 310058, China
| | - Wenjun Wang
- Ningbo Research Institute, Zhejiang University, Ningbo 315100, China; College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou 310058, China
| | - Enbo Xu
- Ningbo Research Institute, Zhejiang University, Ningbo 315100, China; College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou 310058, China
| | - Tian Ding
- Ningbo Research Institute, Zhejiang University, Ningbo 315100, China; College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou 310058, China
| | - Xingqian Ye
- Ningbo Research Institute, Zhejiang University, Ningbo 315100, China; College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou 310058, China
| | - Jianwei Zhou
- NingboTech University, Ningbo 315100, China; Ningbo Research Institute, Zhejiang University, Ningbo 315100, China.
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Genetic Factors Affect the Survival and Behaviors of Selected Bacteria during Antimicrobial Blue Light Treatment. Int J Mol Sci 2021; 22:ijms221910452. [PMID: 34638788 PMCID: PMC8508746 DOI: 10.3390/ijms221910452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 12/26/2022] Open
Abstract
Antimicrobial resistance is a global, mounting and dynamic issue that poses an immediate threat to human, animal, and environmental health. Among the alternative antimicrobial treatments proposed to reduce the external use of antibiotics is electromagnetic radiation, such as blue light. The prevailing mechanistic model is that blue light can be absorbed by endogenous porphyrins within the bacterial cell, inducing the production of reactive oxygen species, which subsequently inflict oxidative damages upon different cellular components. Nevertheless, it is unclear whether other mechanisms are involved, particularly those that can affect the efficacy of antimicrobial blue light treatments. In this review, we summarize evidence of inherent factors that may confer protection to a selected group of bacteria against blue light-induced oxidative damages or modulate the physiological characteristics of the treated bacteria, such as virulence and motility. These include descriptions of three major photoreceptors in bacteria, chemoreceptors, SOS-dependent DNA repair and non-SOS protective mechanisms. Future directions are also provided to assist with research efforts to increase the efficacy of antimicrobial blue light and to minimize the development of blue light-tolerant phenotypes.
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Balotf S, Wilson R, Tegg RS, Nichols DS, Wilson CR. In Planta Transcriptome and Proteome Profiles of Spongospora subterranea in Resistant and Susceptible Host Environments Illuminates Regulatory Principles Underlying Host-Pathogen Interaction. BIOLOGY 2021; 10:biology10090840. [PMID: 34571717 PMCID: PMC8471823 DOI: 10.3390/biology10090840] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 01/13/2023]
Abstract
Simple Summary Infections of potato tubers and roots by Spongospora subterranea result in powdery scab and root diseases. Losses due to infections with S. subterranea are substantial in most potato-growing regions of the world with no fully effective treatments available. Understanding the gene regulation of pathogens in their host is dependent on multidimensional datasets. In this study, we profiled the transcriptome and proteome of S. subterranea within the susceptible and resistant host. Enzyme activity and nucleic acid metabolism appear to be important to the virulence of S. subterranea. Our results provide a good resource for future functional studies of powdery scab and might be useful in S. subterranea inoculum management. Abstract Spongospora subterranea is an obligate biotrophic pathogen, causing substantial economic loss to potato industries globally. Currently, there are no fully effective management strategies for the control of potato diseases caused by S. subterranea. To further our understanding of S. subterranea biology during infection, we characterized the transcriptome and proteome of the pathogen during the invasion of roots of a susceptible and a resistant potato cultivar. A total of 7650 transcripts from S. subterranea were identified in the transcriptome analysis in which 1377 transcripts were differentially expressed between two cultivars. In proteome analysis, we identified 117 proteins with 42 proteins significantly changed in comparisons between resistant and susceptible cultivars. The functional annotation of transcriptome data indicated that the gene ontology terms related to the transportation and actin processes were induced in the resistant cultivar. The downregulation of enzyme activity and nucleic acid metabolism in the resistant cultivar suggests a probable influence of these processes in the virulence of S. subterranea. The protein analysis results indicated that the majority of differentially expressed proteins were related to the metabolic processes and transporter activity. The present study provides a comprehensive molecular insight into the multiple layers of gene regulation that contribute to S. subterranea infection and development in planta and illuminates the role of host immunity in affecting pathogen responses.
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Affiliation(s)
- Sadegh Balotf
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, New Town, TAS 7008, Australia; (S.B.); (R.S.T.)
| | - Richard Wilson
- Central Science Laboratory, University of Tasmania, Hobart, TAS 7001, Australia; (R.W.); (D.S.N.)
| | - Robert S. Tegg
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, New Town, TAS 7008, Australia; (S.B.); (R.S.T.)
| | - David S. Nichols
- Central Science Laboratory, University of Tasmania, Hobart, TAS 7001, Australia; (R.W.); (D.S.N.)
| | - Calum R. Wilson
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, New Town, TAS 7008, Australia; (S.B.); (R.S.T.)
- Correspondence:
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What's new and notable in bacterial spore killing! World J Microbiol Biotechnol 2021; 37:144. [PMID: 34351499 PMCID: PMC8342367 DOI: 10.1007/s11274-021-03108-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/05/2021] [Indexed: 02/08/2023]
Abstract
Spores of many species of the orders Bacillales and Clostridiales can be vectors for food spoilage, human diseases and intoxications, and biological warfare. Many agents are used for spore killing, including moist heat in an autoclave, dry heat at elevated temperatures, UV radiation at 254 and more recently 222 and 400 nm, ionizing radiation of various types, high hydrostatic pressures and a host of chemical decontaminants. An alternative strategy is to trigger spore germination, as germinated spores are much easier to kill than the highly resistant dormant spores—the so called “germinate to eradicate” strategy. Factors important to consider in choosing methods for spore killing include the: (1) cost; (2) killing efficacy and kinetics; (3) ability to decontaminate large areas in buildings or outside; and (4) compatibility of killing regimens with the: (i) presence of people; (ii) food quality; (iii) presence of significant amounts of organic matter; and (iv) minimal damage to equipment in the decontamination zone. This review will summarize research on spore killing and point out some common flaws which can make results from spore killing research questionable.
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Hoenes K, Bauer R, Spellerberg B, Hessling M. Microbial Photoinactivation by Visible Light Results in Limited Loss of Membrane Integrity. Antibiotics (Basel) 2021; 10:341. [PMID: 33807025 PMCID: PMC8005082 DOI: 10.3390/antibiotics10030341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 01/07/2023] Open
Abstract
Interest in visible light irradiation as a microbial inactivation method has widely increased due to multiple possible applications. Resistance development is considered unlikely, because of the multi-target mechanism, based on the induction of reactive oxygen species by wavelength specific photosensitizers. However, the affected targets are still not completely identified. We investigated membrane integrity with the fluorescence staining kit LIVE/DEAD® BacLight™ on a Gram positive and a Gram negative bacterial species, irradiating Staphylococcus carnosus and Pseudomonas fluorescens with 405 nm and 450 nm. To exclude the generation of viable but nonculturable (VBNC) bacterial cells, we applied an ATP test, measuring the loss of vitality. Pronounced uptake of propidium iodide was only observed in Pseudomonas fluorescens at 405 nm. Transmission electron micrographs revealed no obvious differences between irradiated samples and controls, especially no indication of an increased bacterial cell lysis could be observed. Based on our results and previous literature, we suggest that visible light photoinactivation does not lead to rapid bacterial cell lysis or disruption. However, functional loss of membrane integrity due to depolarization or inactivation of membrane proteins may occur. Decomposition of the bacterial envelope following cell death might be responsible for observations of intracellular component leakage.
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Affiliation(s)
- Katharina Hoenes
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, 89081 Ulm, Germany;
| | - Richard Bauer
- Institute of Medical Microbiology and Hygiene, University Hospital Ulm, 89081 Ulm, Germany; (R.B.); (B.S.)
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University Hospital Ulm, 89081 Ulm, Germany; (R.B.); (B.S.)
| | - Martin Hessling
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, 89081 Ulm, Germany;
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17
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Hoenes K, Bauer R, Meurle T, Spellerberg B, Hessling M. Inactivation Effect of Violet and Blue Light on ESKAPE Pathogens and Closely Related Non-pathogenic Bacterial Species - A Promising Tool Against Antibiotic-Sensitive and Antibiotic-Resistant Microorganisms. Front Microbiol 2021; 11:612367. [PMID: 33519770 PMCID: PMC7838345 DOI: 10.3389/fmicb.2020.612367] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/11/2020] [Indexed: 01/20/2023] Open
Abstract
Due to the globally observed increase in antibiotic resistance of bacterial pathogens and the simultaneous decline in new antibiotic developments, the need for alternative inactivation approaches is growing. This is especially true for the treatment of infections with the problematic ESKAPE pathogens, which include Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species, and often exhibit multiple antibiotic resistances. Irradiation with visible light from the violet and blue spectral range is an inactivation approach that does not require any additional supplements. Multiple bacterial and fungal species were demonstrated to be sensitive to this disinfection technique. In the present study, pathogenic ESKAPE organisms and non-pathogenic relatives are irradiated with visible blue and violet light with wavelengths of 450 and 405 nm, respectively. The irradiation experiments are performed at 37°C to test a potential application for medical treatment. For all investigated microorganisms and both wavelengths, a decrease in colony forming units is observed with increasing irradiation dose, although there are differences between the examined bacterial species. A pronounced difference can be observed between Acinetobacter, which prove to be particularly light sensitive, and enterococci, which need higher irradiation doses for inactivation. Differences between pathogenic and non-pathogenic bacteria of one genus are comparatively small, with the tendency of non-pathogenic representatives being less susceptible. Visible light irradiation is therefore a promising approach to inactivate ESKAPE pathogens with future fields of application in prevention and therapy.
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Affiliation(s)
- Katharina Hoenes
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
| | - Richard Bauer
- Institute of Medical Microbiology and Hygiene, University Hospital Ulm, Ulm, Germany
| | - Tobias Meurle
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
| | - Barbara Spellerberg
- Institute of Medical Microbiology and Hygiene, University Hospital Ulm, Ulm, Germany
| | - Martin Hessling
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
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Francés-Monerris A, Hognon C, Douki T, Monari A. Photoinduced DNA Lesions in Dormant Bacteria: The Peculiar Route Leading to Spore Photoproducts Characterized by Multiscale Molecular Dynamics*. Chemistry 2020; 26:14236-14241. [PMID: 32597544 DOI: 10.1002/chem.202002484] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Indexed: 11/07/2022]
Abstract
Some bacterial species enter a dormant state in the form of spores to resist to unfavorable external conditions. Spores are resistant to a wide series of stress agents, including UV radiation, and can last for tens to hundreds of years. Due to the suspension of biological functions, such as DNA repair, they accumulate DNA damage upon exposure to UV radiation. Differently from active organisms, the most common DNA photoproducts in spores are not cyclobutane pyrimidine dimers, but rather the so-called spore photoproducts. This noncanonical photochemistry results from the dry state of DNA and its binding to small, acid-soluble proteins that drastically modify the structure and photoreactivity of the nucleic acid. Herein, multiscale molecular dynamics simulations, including extended classical molecular dynamics and quantum mechanics/molecular mechanics based dynamics, are used to elucidate the coupling of electronic and structural factors that lead to this photochemical outcome. In particular, the well-described impact of the peculiar DNA environment found in spores on the favored formation of the spore photoproduct, given the small free energy barrier found for this path, is rationalized. Meanwhile, the specific organization of spore DNA precludes the photochemical path that leads to cyclobutane pyrimidine dimer formation.
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Affiliation(s)
- Antonio Francés-Monerris
- Université de Lorraine and CNRS, LPCT UMR 7019, 54000, Nancy, France
- Departament de Química Física, Universitat de València, 46100, Burjassot, Spain
| | - Cécilia Hognon
- Université de Lorraine and CNRS, LPCT UMR 7019, 54000, Nancy, France
- Université de Lorraine and CNRS, CRAN UMR 7039, 54000, Nancy, France
| | - Thierry Douki
- SyMMES, CEA, CNRS, IRIG, University Grenoble Alpes, 38000, Grenoble, France
| | - Antonio Monari
- Université de Lorraine and CNRS, LPCT UMR 7019, 54000, Nancy, France
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19
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Zhang Y, Huber N, Moeller R, Stülke J, Dubovcova B, Akepsimaidis G, Meneses N, Drissner D, Mathys A. Role of DNA repair in Bacillus subtilis spore resistance to high energy and low energy electron beam treatments. Food Microbiol 2020; 87:103353. [DOI: 10.1016/j.fm.2019.103353] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 09/04/2019] [Accepted: 10/23/2019] [Indexed: 10/25/2022]
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20
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Taylor W, Camilleri E, Craft DL, Korza G, Granados MR, Peterson J, Szczpaniak R, Weller SK, Moeller R, Douki T, Mok WWK, Setlow P. DNA Damage Kills Bacterial Spores and Cells Exposed to 222-Nanometer UV Radiation. Appl Environ Microbiol 2020; 86:AEM.03039-19. [PMID: 32033948 PMCID: PMC7117916 DOI: 10.1128/aem.03039-19] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 02/03/2020] [Indexed: 01/16/2023] Open
Abstract
This study examined the microbicidal activity of 222-nm UV radiation (UV222), which is potentially a safer alternative to the 254-nm UV radiation (UV254) that is often used for surface decontamination. Spores and/or growing and stationary-phase cells of Bacillus cereus, Bacillus subtilis, Bacillus thuringiensis, Staphylococcus aureus, and Clostridioides difficile and a herpesvirus were all killed or inactivated by UV222 and at lower fluences than with UV254B. subtilis spores and cells lacking the major DNA repair protein RecA were more sensitive to UV222, as were spores lacking their DNA-protective proteins, the α/β-type small, acid-soluble spore proteins. The spore cores' large amount of Ca2+-dipicolinic acid (∼25% of the core dry weight) also protected B. subtilis and C. difficile spores against UV222, while spores' proteinaceous coat may have given some slight protection against UV222 Survivors among B. subtilis spores treated with UV222 acquired a large number of mutations, and this radiation generated known mutagenic photoproducts in spore and cell DNA, primarily cyclobutane-type pyrimidine dimers in growing cells and an α-thyminyl-thymine adduct termed the spore photoproduct (SP) in spores. Notably, the loss of a key SP repair protein markedly decreased spore UV222 resistance. UV222-treated B. subtilis spores germinated relatively normally, and the generation of colonies from these germinated spores was not salt sensitive. The latter two findings suggest that UV222 does not kill spores by general protein damage, and thus, the new results are consistent with the notion that DNA damage is responsible for the killing of spores and cells by UV222IMPORTANCE Spores of a variety of bacteria are resistant to common decontamination agents, and many of them are major causes of food spoilage and some serious human diseases, including anthrax caused by spores of Bacillus anthracis Consequently, there is an ongoing need for efficient methods for spore eradication, in particular methods that have minimal deleterious effects on people or the environment. UV radiation at 254 nm (UV254) is sporicidal and commonly used for surface decontamination but can cause deleterious effects in humans. Recent work, however, suggests that 222-nm UV (UV222) may be less harmful to people than UV254 yet may still kill bacteria and at lower fluences than UV254 The present work has identified the damage by UV222 that leads to the killing of growing cells and spores of some bacteria, many of which are human pathogens, and UV222 also inactivates a herpesvirus.
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Affiliation(s)
- Willie Taylor
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Emily Camilleri
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - D Levi Craft
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - George Korza
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Maria Rocha Granados
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Jaliyah Peterson
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Renata Szczpaniak
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Sandra K Weller
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Ralf Moeller
- Space Microbiology Research Group, Radiation Biology Department, Institute for Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Thierry Douki
- Universite Grenoble Alpes, CEA, CNRS, INAC-SYMMBEST, Grenoble, France
| | - Wendy W K Mok
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
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21
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Clair G, Esbelin J, Malléa S, Bornard I, Carlin F. The spore coat is essential for Bacillus subtilis spore resistance to pulsed light, and pulsed light treatment eliminates some spore coat proteins. Int J Food Microbiol 2020; 323:108592. [PMID: 32315871 DOI: 10.1016/j.ijfoodmicro.2020.108592] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 12/11/2019] [Accepted: 03/15/2020] [Indexed: 01/26/2023]
Abstract
Microbial surface contamination of equipment or of food contact material is a recurring problem in the food industry. Spore-forming bacteria are far more resistant to a wide variety of treatments than their vegetative forms. Understanding the mechanisms underlying decontamination processes is needed to improve surface decontamination strategies against endospores potentially at the source of foodborne diseases or food-spoilage. Pulsed light (PL) with xenon lamps delivers high-energy short-time pulses of light with wavelengths in the range 200 nm-1100 nm and a high UV-C fraction. Bacillus subtilis spores were exposed to either PL or to continuous UV-C. Gel electrophoresis and western blotting revealed elimination of various proteins of the spore coat, an essential outer structure that protects spores from a wide variety of environmental conditions and inactivation treatments. Proteomic analysis confirmed the elimination of some spore coat proteins after PL treatment. Transmission electron microscopy of PL treated spores revealed a gap between the lamellar inner spore coat and the outer spore coat. Overall, spores of mutant strains with defects in genes coding for spore coat proteins were more sensitive to PL than to continuous UV-C. This study demonstrates that radiations delivered by PL contribute to specific damage to the spore coat, and overall to spore inactivation.
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Affiliation(s)
- Gérémy Clair
- INRAE, Avignon Université, UMR SQPOV, F-84000, Avignon, France; Integrative Omics, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352, USA
| | - Julia Esbelin
- INRAE, Avignon Université, UMR SQPOV, F-84000, Avignon, France
| | - Sabine Malléa
- INRAE, Avignon Université, UMR SQPOV, F-84000, Avignon, France
| | | | - Frédéric Carlin
- INRAE, Avignon Université, UMR SQPOV, F-84000, Avignon, France.
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22
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Accumulation and Release of Rare Earth Ions by Spores of Bacillus Species and the Location of These Ions in Spores. Appl Environ Microbiol 2019; 85:AEM.00956-19. [PMID: 31253678 DOI: 10.1128/aem.00956-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 06/20/2019] [Indexed: 12/28/2022] Open
Abstract
Two rare earth ions, Tb3+ and Dy3+, were incorporated into spores of Bacillus species in ≤5 min at neutral pH to 100 to 200 nmol per mg of dry spores, which is equivalent to 2 to 3% of the spore dry weight. The uptake of these ions had, at most, minimal effects on spore wet heat resistance or germination, and the ions were all released upon germination, probably by complex formation with the huge depot of dipicolinic acid (DPA) released when spores germinate. Adsorbed Tb3+/Dy3+ were also released by exogenous DPA within a few minutes and faster than in spore germination. The accumulation of Tb3+/Dy3+ was not reduced in Bacillus subtilis spores by several types of coat defects, significant modification of the spore cortex peptidoglycan structure, specific loss of components of the outer spore crust layer, or the absence of DPA in the spore core. All of these findings are consistent with Tb3+/Dy3+ being accumulated in spores' outer layers, and this was confirmed by transmission electron microscopy. However, the identity of the outer spore components binding the Tb3+/Dy3+ is not clear. These findings provide new information on the adsorption of rare earth ions by Bacillus spores and suggest this adsorption might have applications in capturing rare earth ions from the environment.IMPORTANCE Biosorption of rare earth ions by growing cells of Bacillus species has been well studied and has attracted attention for possible hydrometallurgy applications. However, the interaction of spores from Bacillus species with rare earth ions has not been well studied. We investigated here the adsorption and/or desorption of two rare earth ions, Tb3+ and Dy3+, by Bacillus spores, the location of the adsorbed ions, and the spore properties after ion accumulation. The significant adsorption of rare earth ions on the surfaces of Bacillus spores and the ions' rapid release by a chelator could allow the development of these spores as a biosorbent to recover rare earth ions from the environment.
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23
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Ghosh S, Joseph G, Korza G, He L, Yuan J, Dong W, Setlow B, Li Y, Savage P, Setlow P. Effects of the microbicide ceragenin CSA‐13 on and properties ofBacillus subtilisspores prepared on two very different media. J Appl Microbiol 2019; 127:109-120. [DOI: 10.1111/jam.14300] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 03/23/2019] [Accepted: 04/30/2019] [Indexed: 12/25/2022]
Affiliation(s)
- S. Ghosh
- Department of Molecular Biology and Biophysics UConn Health Farmington CT USA
- Department of Science and Mathematics Capital Community College Hartford CT USA
| | - G. Joseph
- Department of Molecular Biology and Biophysics UConn Health Farmington CT USA
| | - G. Korza
- Department of Molecular Biology and Biophysics UConn Health Farmington CT USA
| | - L. He
- Department of Physics East Carolina University Greenville NC USA
- School of Electronic Engineering Dongguan University of Technology Dongguan People’s Republic of China
| | - J.‐H. Yuan
- Department of Physics East Carolina University Greenville NC USA
| | - W. Dong
- Department of Molecular Biology and Biophysics UConn Health Farmington CT USA
- School of Resource and Environmental Engineering Jiangxi University of Science and Technology Ganzhou China
| | - B. Setlow
- Department of Molecular Biology and Biophysics UConn Health Farmington CT USA
| | - Y.‐Q. Li
- Department of Physics East Carolina University Greenville NC USA
- School of Electronic Engineering Dongguan University of Technology Dongguan People’s Republic of China
| | - P.B. Savage
- Department of Chemistry and Biochemistry Brigham Young University Provo UT USA
| | - P. Setlow
- Department of Molecular Biology and Biophysics UConn Health Farmington CT USA
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Cortesão M, Fuchs FM, Commichau FM, Eichenberger P, Schuerger AC, Nicholson WL, Setlow P, Moeller R. Bacillus subtilis Spore Resistance to Simulated Mars Surface Conditions. Front Microbiol 2019; 10:333. [PMID: 30863384 PMCID: PMC6399134 DOI: 10.3389/fmicb.2019.00333] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/08/2019] [Indexed: 11/13/2022] Open
Abstract
In a Mars exploration scenario, knowing if and how highly resistant Bacillus subtilis spores would survive on the Martian surface is crucial to design planetary protection measures and avoid false positives in life-detection experiments. Therefore, in this study a systematic screening was performed to determine whether B. subtilis spores could survive an average day on Mars. For that, spores from two comprehensive sets of isogenic B. subtilis mutant strains, defective in DNA protection or repair genes, were exposed to 24 h of simulated Martian atmospheric environment with or without 8 h of Martian UV radiation [M(+)UV and M(-)UV, respectively]. When exposed to M(+)UV, spore survival was dependent on: (1) core dehydration maintenance, (2) protection of DNA by α/β-type small acid soluble proteins (SASP), and (3) removal and repair of the major UV photoproduct (SP) in spore DNA. In turn, when exposed to M(-)UV, spore survival was mainly dependent on protection by the multilayered spore coat, and DNA double-strand breaks represent the main lesion accumulated. Bacillus subtilis spores were able to survive for at least a limited time in a simulated Martian environment, both with or without solar UV radiation. Moreover, M(-)UV-treated spores exhibited survival rates significantly higher than the M(+)UV-treated spores. This suggests that on a real Martian surface, radiation shielding of spores (e.g., by dust, rocks, or spacecraft surface irregularities) might significantly extend survival rates. Mutagenesis were strongly dependent on the functionality of all structural components with small acid-soluble spore proteins, coat layers and dipicolinic acid as key protectants and efficiency DNA damage removal by AP endonucleases (ExoA and Nfo), non-homologous end joining (NHEJ), mismatch repair (MMR) and error-prone translesion synthesis (TLS). Thus, future efforts should focus on: (1) determining the DNA damage in wild-type spores exposed to M(+/-)UV and (2) assessing spore survival and viability with shielding of spores via Mars regolith and other relevant materials.
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Affiliation(s)
- Marta Cortesão
- Space Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Felix M Fuchs
- Space Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Fabian M Commichau
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Patrick Eichenberger
- Department of Biology, Center for Genomics and Systems Biology, New York University, New York, NY, United States
| | - Andrew C Schuerger
- Department of Plant Pathology, Space Life Sciences Laboratory, University of Florida, Merritt Island, FL, United States
| | - Wayne L Nicholson
- Department of Microbiology and Cell Science, Space Life Sciences Laboratory, University of Florida, Merritt Island, FL, United States
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, United States
| | - Ralf Moeller
- Space Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
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25
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Setlow P. Observations on research with spores of Bacillales and Clostridiales species. J Appl Microbiol 2019; 126:348-358. [PMID: 30106202 PMCID: PMC6329651 DOI: 10.1111/jam.14067] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 08/03/2018] [Accepted: 08/07/2018] [Indexed: 01/06/2023]
Abstract
The purpose of this article is to highlight some areas of research with spores of bacteria of Firmicute species in which the methodology too commonly used is not optimal and generates misleading results. As a consequence, conclusions drawn from data obtained are often flawed or not appropriate. Topics covered in the article include the following: (i) the importance of using well-purified bacterial spores in studies on spore resistance, composition, killing, disinfection and germination; (ii) methods for obtaining good purification of spores of various species; (iii) appropriate experimental approaches to determine mechanisms of spore resistance and spore killing by a variety of agents, as well as known mechanisms of spore resistance and killing; (iv) common errors made in drawing conclusions about spore killing by various agents, including failure to neutralize chemical agents before plating for viable spore enumeration, and equating correlations between changes in spore properties accompanying spore killing with causation. It is hoped that a consideration of these topics will improve the quality of spore research going forward.
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Affiliation(s)
- Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030-3305 USA
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