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Bauda E, Gallet B, Moravcova J, Effantin G, Chan H, Novacek J, Jouneau PH, Rodrigues CDA, Schoehn G, Moriscot C, Morlot C. Ultrastructure of macromolecular assemblies contributing to bacterial spore resistance revealed by in situ cryo-electron tomography. Nat Commun 2024; 15:1376. [PMID: 38355696 PMCID: PMC10867305 DOI: 10.1038/s41467-024-45770-6] [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: 09/06/2023] [Accepted: 02/02/2024] [Indexed: 02/16/2024] Open
Abstract
Bacterial spores owe their incredible resistance capacities to molecular structures that protect the cell content from external aggressions. Among the determinants of resistance are the quaternary structure of the chromosome and an extracellular shell made of proteinaceous layers (the coat), the assembly of which remains poorly understood. Here, in situ cryo-electron tomography on lamellae generated by cryo-focused ion beam micromachining provides insights into the ultrastructural organization of Bacillus subtilis sporangia. The reconstructed tomograms reveal that early during sporulation, the chromosome in the forespore adopts a toroidal structure harboring 5.5-nm thick fibers. At the same stage, coat proteins at the surface of the forespore form a stack of amorphous or structured layers with distinct electron density, dimensions and organization. By analyzing mutant strains using cryo-electron tomography and transmission electron microscopy on resin sections, we distinguish seven nascent coat regions with different molecular properties, and propose a model for the contribution of coat morphogenetic proteins.
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Affiliation(s)
- Elda Bauda
- Univ. Grenoble Alpes, CNRS, CEA, IBS, F-38000, Grenoble, France
| | - Benoit Gallet
- Univ. Grenoble Alpes, CNRS, CEA, IBS, F-38000, Grenoble, France
| | - Jana Moravcova
- CEITEC-Central European Institute of Technology, Masaryk University, 62500, Brno, Czech Republic
| | | | - Helena Chan
- University of Technology Sydney, 2007, Ultimo, NSW, Australia
| | - Jiri Novacek
- CEITEC-Central European Institute of Technology, Masaryk University, 62500, Brno, Czech Republic
| | | | | | - Guy Schoehn
- Univ. Grenoble Alpes, CNRS, CEA, IBS, F-38000, Grenoble, France
| | | | - Cecile Morlot
- Univ. Grenoble Alpes, CNRS, CEA, IBS, F-38000, Grenoble, France.
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2
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Boubsi F, Hoff G, Arguelles Arias A, Steels S, Andrić S, Anckaert A, Roulard R, Rigolet A, van Wuytswinkel O, Ongena M. Pectic homogalacturonan sensed by Bacillus acts as host associated cue to promote establishment and persistence in the rhizosphere. iScience 2023; 26:107925. [PMID: 37790276 PMCID: PMC10543691 DOI: 10.1016/j.isci.2023.107925] [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: 04/07/2023] [Revised: 07/19/2023] [Accepted: 09/12/2023] [Indexed: 10/05/2023] Open
Abstract
Bacillus velezensis isolates are among the most promising plant-associated beneficial bacteria used as biocontrol agents. However, various aspects of the chemical communication between the plant and these beneficials, determining root colonization ability, remain poorly described. Here we investigated the molecular basis of such interkingdom interaction occurring upon contact between Bacillus velezensis and its host via the sensing of pectin backbone homogalacturonan (HG). We showed that B. velezensis stimulates key developmental traits via a dynamic process involving two conserved pectinolytic enzymes. This response integrates transcriptional changes leading to the switch from planktonic to sessile cells, a strong increase in biofilm formation, and an accelerated sporulation dynamics while conserving the potential to efficiently produce specialized secondary metabolites. As a whole, we anticipate that this response of Bacillus to cell wall-derived host cues contributes to its establishment and persistence in the competitive rhizosphere niche and ipso facto to its activity as biocontrol agent.
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Affiliation(s)
- Farah Boubsi
- Microbial Processes and Interactions, TERRA Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
| | - Grégory Hoff
- Microbial Processes and Interactions, TERRA Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
| | - Anthony Arguelles Arias
- Microbial Processes and Interactions, TERRA Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
| | - Sébastien Steels
- Microbial Processes and Interactions, TERRA Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
| | - Sofija Andrić
- Microbial Processes and Interactions, TERRA Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
| | - Adrien Anckaert
- Microbial Processes and Interactions, TERRA Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
| | - Romain Roulard
- UMRT INRAe 1158 Plant Biology and Innovation, University of Picardie Jules Verne, UFR des Sciences, 80039 Amiens, France
| | - Augustin Rigolet
- Microbial Processes and Interactions, TERRA Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
| | - Olivier van Wuytswinkel
- UMRT INRAe 1158 Plant Biology and Innovation, University of Picardie Jules Verne, UFR des Sciences, 80039 Amiens, France
| | - Marc Ongena
- Microbial Processes and Interactions, TERRA Teaching and Research Center, University of Liège - Gembloux Agro-Bio Tech, 5030 Gembloux, Belgium
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Wahia H, Fakayode OA, Mintah BK, Mustapha AT, Zhou C, Dabbour M. Effect of dual-frequency thermosonication, food matrix, and germinants on Alicyclobacillus acidoterrestris spore germination. Food Res Int 2023; 171:113054. [PMID: 37330854 DOI: 10.1016/j.foodres.2023.113054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/19/2023]
Abstract
The off-odors associated with spoilage of acidic beverages are linked to the germination and growth of Alicyclobacillus acidoterrestris (AAT) spores. As a consequence, we determined the influence of nutrients, non-nutrient germinants, dual-frequency thermosonication (DFTS), and food matrix on spore germination. AAT spores in orange juice (OJ), supplemented by L-alanine (L-ala), had the highest germination rate and lowest DPA content at 10 h of incubation. The formation of microscopic pores in cell membranes during DFTS caused irreversible damage in AAT spores in citrate buffer solution (CBS); however, it stimulated AAT spore germination in CBS containing L-ala. Hence, the germination potential was established in the order: L-ala > Calcium dipicolinate > asparagine, glucose, fructose, and potassium ion mixture (AGFK) > L-valine. The conductivity analysis indicated that membrane damage could be a key factor contributing to the artificial germination in CBS. AFM images revealed that after 2 h of adding L-ala, the protein content increased with increased germinated cells. TEM showed that membrane poration and coat detachment were the main pre-germination morphological changes detected after DFTS treatment. This study provides evidence that germination stimulated with DFTS might be an effective strategy for reducing A. acidoterrestris spores in fruit juices.
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Affiliation(s)
- Hafida Wahia
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China
| | | | | | | | - Cunshan Zhou
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, PR China; School of Biological and Food Engineering, Chuzhou University, Chuzhou, 239000, PR China.
| | - Mokhtar Dabbour
- Department of Agricultural and Biosystems Engineering, Faculty of Agriculture, Benha University, PO Box 13736, Moshtohor, Qaluobia, Egypt
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Harrellson SG, DeLay MS, Chen X, Cavusoglu AH, Dworkin J, Stone HA, Sahin O. Hydration solids. Nature 2023; 619:500-505. [PMID: 37286609 PMCID: PMC10530534 DOI: 10.1038/s41586-023-06144-y] [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: 10/05/2017] [Accepted: 04/27/2023] [Indexed: 06/09/2023]
Abstract
Hygroscopic biological matter in plants, fungi and bacteria make up a large fraction of Earth's biomass1. Although metabolically inert, these water-responsive materials exchange water with the environment and actuate movement2-5 and have inspired technological uses6,7. Despite the variety in chemical composition, hygroscopic biological materials across multiple kingdoms of life exhibit similar mechanical behaviours including changes in size and stiffness with relative humidity8-13. Here we report atomic force microscopy measurements on the hygroscopic spores14,15 of a common soil bacterium and develop a theory that captures the observed equilibrium, non-equilibrium and water-responsive mechanical behaviours, finding that these are controlled by the hydration force16-18. Our theory based on the hydration force explains an extreme slowdown of water transport and successfully predicts a strong nonlinear elasticity and a transition in mechanical properties that differs from glassy and poroelastic behaviours. These results indicate that water not only endows biological matter with fluidity but also can-through the hydration force-control macroscopic properties and give rise to a 'hydration solid' with unusual properties. A large fraction of biological matter could belong to this distinct class of solid matter.
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Affiliation(s)
| | - Michael S DeLay
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Xi Chen
- Department of Biological Sciences, Columbia University, New York, NY, USA
- Advanced Science Research Center (ASRC) at the Graduate Center of the City University of New York, New York, NY, USA
| | - Ahmet-Hamdi Cavusoglu
- Department of Chemical Engineering, Columbia University, New York, NY, USA
- Merck Digital Sciences Studio (MDSS), Newark, NJ, USA
| | - Jonathan Dworkin
- Department of Microbiology and Immunology, Columbia University, New York, NY, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA
| | - Ozgur Sahin
- Department of Physics, Columbia University, New York, NY, USA.
- Department of Biological Sciences, Columbia University, New York, NY, USA.
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Xu M, Selvaraj GK, Lu H. Environmental sporobiota: Occurrence, dissemination, and risks. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 869:161809. [PMID: 36702282 DOI: 10.1016/j.scitotenv.2023.161809] [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: 11/22/2022] [Revised: 01/03/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Spore-forming bacteria known as sporobiota are widespread in diverse environments from terrestrial and aquatic habitats to industrial and healthcare systems. Studies on sporobiota have been mainly focused on food processing and clinical fields, while a large amount of sporobiota exist in natural environments. Due to their persistence and capabilities of transmitting virulence factors and antibiotic resistant genes, environmental sporobiota could pose significant health risks to humans. These risks could increase as global warming and environmental pollution has altered the life cycle of sporobiota. This review summarizes the current knowledge of environmental sporobiota, including their occurrence, characteristics, and functions. An interaction network among clinical-, food-related, and environment-related sporobiota is constructed. Recent and effective methods for detecting and disinfecting environmental sporobiota are also discussed. Key problems and future research needs for better understanding and reducing the risks of environmental sporobiota and sporobiome are proposed.
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Affiliation(s)
- Min Xu
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Ganesh-Kumar Selvaraj
- Department of Microbiology, St. Peter's Institute of Higher Education and Research, Chennai 600054, Tamil Nadu, India.
| | - Huijie Lu
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Water Pollution Control and Environmental Safety, Zhejiang, China.
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Corona Ramírez A, Lee KS, Odriozola A, Kaminek M, Stocker R, Zuber B, Junier P. Multiple roads lead to Rome: unique morphology and chemistry of endospores, exospores, myxospores, cysts and akinetes in bacteria. MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 36804869 DOI: 10.1099/mic.0.001299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The production of specialized resting cells is a remarkable survival strategy developed by many organisms to withstand unfavourable environmental factors such as nutrient depletion or other changes in abiotic and/or biotic conditions. Five bacterial taxa are recognized to form specialized resting cells: Firmicutes, forming endospores; Actinobacteria, forming exospores; Cyanobacteria, forming akinetes; the δ-Proteobacterial order Myxococcales, forming myxospores; and Azotobacteraceae, forming cysts. All these specialized resting cells are characterized by low-to-absent metabolic activity and higher resistance to environmental stress (desiccation, heat, starvation, etc.) when compared to vegetative cells. Given their similarity in function, we tested the potential existence of a universal morpho-chemical marker for identifying these specialized resting cells. After the production of endospores, exospores, akinetes and cysts in model organisms, we performed the first cross-species morphological and chemical comparison of bacterial sporulation. Cryo-electron microscopy of vitreous sections (CEMOVIS) was used to describe near-native morphology of the resting cells in comparison to the morphology of their respective vegetative cells. Resting cells shared a thicker cell envelope as their only common morphological feature. The chemical composition of the different specialized resting cells at the single-cell level was investigated using confocal Raman microspectroscopy. Our results show that the different specialized cells do not share a common chemical signature, but rather each group has a unique signature with a variable conservation of the signature of the vegetative cells. Additionally, we present the validation of Raman signatures associated with calcium dipicolinic acid (CaDPA) and their variation across individual cells to develop specific sorting thresholds for the isolation of endospores. This provides a proof of concept of the feasibility of isolating bacterial spores using a Raman-activated cell-sorting platform. This cross-species comparison and the current knowledge of genetic pathways inducing the formation of the resting cells highlights the complexity of this convergent evolutionary strategy promoting bacterial survival.
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Affiliation(s)
- Andrea Corona Ramírez
- Laboratory of Microbiology, Institute of Biology, University of Neuchatel, Neuchatel, Switzerland
| | - Kang Soo Lee
- Department of Civil, Institute for Environmental Engineering, Environmental and Geomatic Engineering, ETH Zurich, Zurich, Switzerland
| | | | - Marek Kaminek
- Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Roman Stocker
- Department of Civil, Institute for Environmental Engineering, Environmental and Geomatic Engineering, ETH Zurich, Zurich, Switzerland
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Pilar Junier
- Laboratory of Microbiology, Institute of Biology, University of Neuchatel, Neuchatel, Switzerland
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7
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Abstract
Clostridioides difficile spores are the infective form for this endospore-forming organism. The vegetative cells are intolerant to oxygen and poor competitors with a healthy gut microbiota. Therefore, in order for C. difficile to establish infection, the spores have to germinate in an environment that supports vegetative growth. To initiate germination, C. difficile uses Csp-type germinant receptors that consist of the CspC and CspA pseudoproteases as the bile acid and cogerminant receptors, respectively. CspB is a subtilisin-like protease that cleaves the inhibitory propeptide from the pro-SleC cortex lytic enzyme, thereby activating it and initiating cortex degradation. Though several locations have been proposed for where these proteins reside within the spore (i.e., spore coat, outer spore membrane, cortex, and inner spore membrane), these have been based, mostly, on hypotheses or prior data in Clostridium perfringens. In this study, we visualized the germination and outgrowth process using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and used immunogold labeling to visualize key germination regulators. These analyses localize these key regulators to the spore cortex region for the first time. IMPORTANCE Germination by C. difficile spores is the first step in the establishment of potentially life-threatening C. difficile infection (CDI). A deeper understanding of the mechanism by which spores germinate may provide insight for how to either prevent spore germination into a disease-causing vegetative form or trigger germination prematurely when the spore is either in the outside environment or in a host environment that does not support the establishment of colonization/disease.
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8
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Abstract
The DNA-binding protein from starved cells, Dps, is a universally conserved prokaryotic ferritin that, in many species, also binds DNA. Dps homologs have been identified in the vast majority of bacterial species and several archaea. Dps also may play a role in the global regulation of gene expression, likely through chromatin reorganization. Dps has been shown to use both its ferritin and DNA-binding functions to respond to a variety of environmental pressures, including oxidative stress. One mechanism that allows Dps to achieve this is through a global nucleoid restructuring event during stationary phase, resulting in a compact, hexacrystalline nucleoprotein complex called the biocrystal that occludes damaging agents from DNA. Due to its small size, hollow spherical structure, and high stability, Dps is being developed for applications in biotechnology.
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Bandopadhyay S, Liquet Y González JE, Henderson KB, Anunciado MB, Hayes DG, DeBruyn JM. Soil Microbial Communities Associated With Biodegradable Plastic Mulch Films. Front Microbiol 2020; 11:587074. [PMID: 33281783 PMCID: PMC7691482 DOI: 10.3389/fmicb.2020.587074] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/20/2020] [Indexed: 11/13/2022] Open
Abstract
Agricultural plastic mulch films provide a favorable soil microclimate for plant growth, improving crop yields. Biodegradable plastic mulch films (BDMs) have emerged as a sustainable alternative to widely used non-biodegradable polyethylene (PE) films. BDMs are tilled into the soil after use and are expected to biodegrade under field conditions. However, little is known about the microbes involved in biodegradation and the relationships between microbes and plastics in soils. In order to capture the consortium of soil microbes associated with (and thus likely degrading) BDMs, agriculturally-weathered plastics from two locations were studied alongside laboratory enrichment experiments to assess differences in the microbial communities associated with BDMs and PE films. Using a combination of amplicon sequencing and quantitative PCR (qPCR), we observed that agriculturally-weathered plastics hosted an enrichment of fungi and an altered bacterial community composition compared to the surrounding soil. Notably, Methylobacterium, Arthrobacter, and Sphingomonas were enriched on BDMs compared to non-biodegradable PE. In laboratory enrichment cultures, microbial consortia were able to degrade the plastics, and the composition of the microbial communities was influenced by the composition of the BDMs. Our initial characterization of the microbial communities associated with biodegradable plastic mulch films, or the biodegradable "plastisphere," lays the groundwork for understanding biodegradation dynamics of biodegradable plastics in the environment.
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Affiliation(s)
- Sreejata Bandopadhyay
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, United States
| | - José E Liquet Y González
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, United States
| | - Kelsey B Henderson
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, United States
| | - Marife B Anunciado
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, United States
| | - Douglas G Hayes
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, United States
| | - Jennifer M DeBruyn
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, United States
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10
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Suzina NE, Polivtseva VN, Shorokhova AP, Ross DV, Abashina TN, Machulin AV, El’-Registan GI, Solyanikova IP. Ultrastructural Organization and Enzymes of the Antioxidant Defense System in the Dormant Cells of Gram-Negative Bacteria Stenotrophomonas sp. Strain FM3 and Morganella morganii subsp. sibonii Strain FF1. Microbiology (Reading) 2019. [DOI: 10.1134/s0026261719020115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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11
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Cross AR, Baldwin VM, Roy S, Essex-Lopresti AE, Prior JL, Harmer NJ. Zoonoses under our noses. Microbes Infect 2019; 21:10-19. [PMID: 29913297 PMCID: PMC6386771 DOI: 10.1016/j.micinf.2018.06.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 11/22/2022]
Abstract
One Health is an effective approach for the management of zoonotic disease in humans, animals and environments. Examples of the management of bacterial zoonoses in Europe and across the globe demonstrate that One Health approaches of international surveillance, information-sharing and appropriate intervention methods are required to successfully prevent and control disease outbreaks in both endemic and non-endemic regions. Additionally, a One Health approach enables effective preparation and response to bioterrorism threats.
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Affiliation(s)
- Alice R Cross
- Living Systems Institute, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD United Kingdom.
| | - Victoria M Baldwin
- Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ United Kingdom
| | - Sumita Roy
- Living Systems Institute, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD United Kingdom
| | | | - Joann L Prior
- Living Systems Institute, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD United Kingdom; Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ United Kingdom; London School of Hygiene & Tropical Medicine, Kepple Street, London WC1E 7HT United Kingdom
| | - Nicholas J Harmer
- Living Systems Institute, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD United Kingdom
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Krupyanskii YF, Loiko NG, Sinitsyn DO, Tereshkina KB, Tereshkin EV, Frolov IA, Chulichkov AL, Bokareva DA, Mysyakina IS, Nikolaev YA, El’-Registan GI, Popov VO, Sokolova OS, Shaitan KV, Popov AN. Biocrystallization in Bacterial and Fungal Cells and Spores. CRYSTALLOGR REP+ 2018. [DOI: 10.1134/s1063774518040144] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Intracellular membranes of bacterial endospores are reservoirs for spore core membrane expansion during spore germination. Sci Rep 2018; 8:11388. [PMID: 30061638 PMCID: PMC6065386 DOI: 10.1038/s41598-018-29879-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/16/2018] [Indexed: 11/08/2022] Open
Abstract
Bacterial endospores are formed by certain bacteria, such as Bacillus subtilis or the pathogenic Bacillus anthracis and Clostridioides difficile, to allow survival in environmental conditions which are lethal to vegetative bacteria. The spores possess a particular architecture and molecular inventory which endow them with a remarkable resistance against desiccation, heat and radiation. Another remarkable spore feature is their rapid return to vegetative growth during spore germination and outgrowth. The underlying processes of this latter physiological and morphological transformation involve a number of different events, some of which are mechanistically not entirely understood. One of these events is the expansion of the central spore core, which contains the DNA, RNA and most spore enzymes. To date, it has been unclear how the ~1.3- to 1.6-fold expansion of the core membrane surface area that accompanies core expansion takes place, since this occurs in the absence of significant if any ATP synthesis. In the current work, we demonstrate the presence of intracellular membrane structures in spores located just below the core membrane. During spore germination these internal core membranes disappear when the core size increases, suggesting that they are integrated into the core membrane to allow core expansion. These intracellular membranes are most probably present as more or less compressed vesicles or tubules within the dormant spore core. Investigations of spores from different species suggest that these intracellular membrane structures below the core membrane are a general feature of endospore forming bacteria.
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14
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Huebinger J, Grabenbauer M. Self-Pressurized Rapid Freezing as Cryo-Fixation Method for Electron Microscopy and Cryopreservation of Living Cells. ACTA ACUST UNITED AC 2018; 79:e47. [PMID: 29924483 DOI: 10.1002/cpcb.47] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Reduction or complete prevention of ice crystal formation during freezing of biological specimens is mandatory for two important biological applications: (1) cryopreservation of living cells or tissues for long-term storage, and (2) cryo-fixation for ultrastructural investigations by electron microscopy. Here, a protocol that is fast, easy-to-use, and suitable for both cryo-fixation and cryopreservation is described. Samples are rapidly cooled in tightly sealed metal tubes of high thermal diffusivity and then plunged into a liquid cryogen. Due to the fast cooling speed and high-pressure buildup internally in the confined volume of the metal tubes, ice crystal formation is reduced or completely prevented, resulting in vitrification of the sample. For cryopreservation, however, a similar principle applies to prevent ice crystal formation during re-warming. A detailed description of procedures for cooling (and re-warming) of biological samples using this technique is provided. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Jan Huebinger
- Department of Systemic Cell Biology, Max-Planck-Institute of Molecular Physiology, Dortmund, Germany
| | - Markus Grabenbauer
- Institute for Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany
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15
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Loiko NG, Suzina NE, Soina VS, Smirnova TA, Zubasheva MV, Azizbekyan RR, Sinitsyn DO, Tereshkina KB, Nikolaev YA, Krupyanskii YF, El’-Registan GI. Biocrystalline structures in the nucleoids of the stationary and dormant prokaryotic cells. Microbiology (Reading) 2017. [DOI: 10.1134/s002626171706011x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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16
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Jamroskovic J, Chromikova Z, List C, Bartova B, Barak I, Bernier-Latmani R. Variability in DPA and Calcium Content in the Spores of Clostridium Species. Front Microbiol 2016; 7:1791. [PMID: 27891119 PMCID: PMC5104732 DOI: 10.3389/fmicb.2016.01791] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/25/2016] [Indexed: 01/31/2023] Open
Abstract
Spores of a number of clostridial species, and their resistance to thermal treatment is a major concern for the food industry. Spore resistance to wet heat is related to the level of spore hydration, which is inversely correlated with the content of calcium and dipicolinic acid (DPA) in the spore core. It is widely believed that the accumulation of DPA and calcium in the spore core is a fundamental component of the sporulation process for all endospore forming species. We have noticed heterogeneity in the heat resistance capacity and overall DPA/calcium content among the spores of several species belonging to Clostridium sensu stricto group: two C. acetobutylicum strains (DSM 792 and 1731), two C. beijerinckii strains (DSM 791 and NCIMB 8052), and a C. collagenovorans strain (DSM 3089). A C. beijerinckii strain (DSM 791) and a C. acetobutylicum strain (DSM 792) display low Ca and DPA levels. In addition, these two species, with the lowest average Ca/DPA content amongst the strains considered, also exhibit minimal heat resistance. There appears to be no correlation between the Ca/DPA content and the phylogenetic distribution of the C. acetobutylicum and C. beijerinckii species based either on the 16S rRNA or the spoVA gene. This finding suggests that a subset of Clostridium sensu stricto species produce spores with low resistance to wet heat. Additionally, analysis of individual spores using STEM-EDS and STXM revealed that DPA and calcium levels can also vary amongst individual spores in a single spore population.
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Affiliation(s)
- Jan Jamroskovic
- Swiss Federal Institute of Technology in Lausanne (EPFL)Lausanne, Switzerland; Institute of Molecular Biology, Slovak Academy of SciencesBratislava, Slovakia
| | - Zuzana Chromikova
- Institute of Molecular Biology, Slovak Academy of Sciences Bratislava, Slovakia
| | - Cornelia List
- Swiss Federal Institute of Technology in Lausanne (EPFL) Lausanne, Switzerland
| | - Barbora Bartova
- Swiss Federal Institute of Technology in Lausanne (EPFL) Lausanne, Switzerland
| | - Imrich Barak
- Institute of Molecular Biology, Slovak Academy of Sciences Bratislava, Slovakia
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Irobalieva RN, Martins B, Medalia O. Cellular structural biology as revealed by cryo-electron tomography. J Cell Sci 2016; 129:469-76. [DOI: 10.1242/jcs.171967] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
ABSTRACT
Understanding the function of cellular machines requires a thorough analysis of the structural elements that underline their function. Electron microscopy (EM) has been pivotal in providing information about cellular ultrastructure, as well as macromolecular organization. Biological materials can be physically fixed by vitrification and imaged with cryo-electron tomography (cryo-ET) in a close-to-native condition. Using this technique, one can acquire three-dimensional (3D) information about the macromolecular architecture of cells, depict unique cellular states and reconstruct molecular networks. Technical advances over the last few years, such as improved sample preparation and electron detection methods, have been instrumental in obtaining data with unprecedented structural details. This presents an exciting opportunity to explore the molecular architecture of both individual cells and multicellular organisms at nanometer to subnanometer resolution. In this Commentary, we focus on the recent developments and in situ applications of cryo-ET to cell and structural biology.
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Affiliation(s)
- Rossitza N. Irobalieva
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Bruno Martins
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University, Beer-Sheva 84105, Israel
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