1
|
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.
Collapse
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
| |
Collapse
|
2
|
Vorländer K, Bahlmann L, Kwade A, Henrik Finke J, Kampen I. Influence of compression kinetics during tableting of fluidized bed-granulated microorganisms on microbiological and physical-mechanical tablet properties. Eur J Pharm Biopharm 2023:S0939-6411(23)00134-0. [PMID: 37207944 DOI: 10.1016/j.ejpb.2023.05.012] [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: 03/26/2023] [Revised: 05/12/2023] [Accepted: 05/12/2023] [Indexed: 05/21/2023]
Abstract
As tablets are convenient to administer to patients, ensure safe dosing and allow cost-effective production on a large scale, they are the favored dosage form for numerous active pharmaceutical ingredients but also for the administration of viable probiotic microorganisms. Granules with viable yeast cells (Saccharomyces cerevisiae) formed by fluidized bed granulation with dicalcium phosphate (DCP), lactose (LAC) or microcrystalline cellulose (MCC) as carrier materials were tableted using a compaction simulator. Besides the compression stress, the compression speed was systematically studied by varying consolidation time and dwell time. The microbial survival as well as physical properties of the tablets, e.g., porosity and tensile strength, were determined. Higher compression stresses result in lower porosities. While on the one hand this has a detrimental effect on microbial survival (due to increased pressure and shear stress during particle rearrangement / densification), on the other hand it results in higher tensile strengths. At the same compression stress, a prolonged dwell time resulted in lower porosity and thus in lower survival rates but higher tensile strength. Against that, consolidation time showed no significant influence on the considered tablet quality attributes. Since changes of the tensile strength related survival rate were negligible (due to opposite but balancing dependence on porosity), high production speeds could be used for tableting of these granules without additional loss of viability, as long as tablets with the same tensile strength are produced.
Collapse
Affiliation(s)
- Karl Vorländer
- Technische Universität Braunschweig, Institute for Particle Technology (iPAT), Volkmaroder Straße 5, 38104 Braunschweig, Germany; Technische Universität Braunschweig, Center of Pharmaceutical Engineering (PVZ), Franz-Liszt-Straße 35A, 38106 Braunschweig, Germany.
| | - Lukas Bahlmann
- Technische Universität Braunschweig, Institute for Particle Technology (iPAT), Volkmaroder Straße 5, 38104 Braunschweig, Germany; Technische Universität Braunschweig, Center of Pharmaceutical Engineering (PVZ), Franz-Liszt-Straße 35A, 38106 Braunschweig, Germany
| | - Arno Kwade
- Technische Universität Braunschweig, Institute for Particle Technology (iPAT), Volkmaroder Straße 5, 38104 Braunschweig, Germany; Technische Universität Braunschweig, Center of Pharmaceutical Engineering (PVZ), Franz-Liszt-Straße 35A, 38106 Braunschweig, Germany
| | - Jan Henrik Finke
- Technische Universität Braunschweig, Institute for Particle Technology (iPAT), Volkmaroder Straße 5, 38104 Braunschweig, Germany; Technische Universität Braunschweig, Center of Pharmaceutical Engineering (PVZ), Franz-Liszt-Straße 35A, 38106 Braunschweig, Germany
| | - Ingo Kampen
- Technische Universität Braunschweig, Institute for Particle Technology (iPAT), Volkmaroder Straße 5, 38104 Braunschweig, Germany; Technische Universität Braunschweig, Center of Pharmaceutical Engineering (PVZ), Franz-Liszt-Straße 35A, 38106 Braunschweig, Germany
| |
Collapse
|
3
|
Isawumi A, Ayerakwa EA, Abban MK, Mosi L. Expression profiles of sporulation genes in multidrug-resistant Bacillus species isolated from intensive care units of Ghanaian hospital. Exp Biol Med (Maywood) 2023; 248:501-507. [PMID: 37092757 PMCID: PMC10281534 DOI: 10.1177/15353702231160336] [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: 10/25/2022] [Accepted: 01/24/2023] [Indexed: 04/25/2023] Open
Abstract
Sporulating bacteria such as Bacillus spp. have contributed to severity of opportunistic hospital acquired infections, including postoperative wounds and respiratory tract infections. This study determines the expression profiles of sporulation markers in multidrug-resistant Bacillus spp. isolated from Ghanaian hospital environments. Antimicrobial resistance (AMR) profiles of the bacteria were determined with disk diffusion and broth microdilution. Primer-specific polymerase chain reaction (PCR) amplification was used to profile the sporulation markers, and quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used for the expression of the sporulation markers at different antibiotic concentrations. The strains are multidrug resistant (70-100%) to at least two of the eight classes of the antibiotics tested including cephalosporins, penicillin, aminoglycosides, and glycopeptide. The strains showed different resistance patterns to all the tested antibiotics, which might indicate diverse resistance mechanisms. Common (spoVK spoVE, spoJ, and sigF) and not commonly (sigJ, soJ, yrbC, and yjcE) reported sporulation markers were detected in the strains. The study showed an association of the sporulation markers with AMR as indicated by their expression profiles.
Collapse
Affiliation(s)
- Abiola Isawumi
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Volta Road, P.O. Box LG 54, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Volta Road, P.O. Box LG 54, Legon, Accra, Ghana
| | - Eunice Ampadubea Ayerakwa
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Volta Road, P.O. Box LG 54, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Volta Road, P.O. Box LG 54, Legon, Accra, Ghana
| | - Molly Kukua Abban
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Volta Road, P.O. Box LG 54, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Volta Road, P.O. Box LG 54, Legon, Accra, Ghana
| | - Lydia Mosi
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Volta Road, P.O. Box LG 54, Legon, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Volta Road, P.O. Box LG 54, Legon, Accra, Ghana
| |
Collapse
|
4
|
Liu ZL, Chen X. Water-Content-Dependent Morphologies and Mechanical Properties of Bacillus subtilis Spores' Cortex Peptidoglycan. ACS Biomater Sci Eng 2022; 8:5094-5100. [PMID: 36442506 DOI: 10.1021/acsbiomaterials.2c01209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptidoglycan (PG), bacterial spores' major structural component in their cortex layers, was recently found to regulate the spore's water content and deform in response to relative humidity (RH) changes. Here, we report that the cortex PG dominates the Bacillus subtilis spores' water-content-dependent morphological and mechanical properties. When exposed to an environment having RH varied between 10% and 90%, the spores and their cortex PG reversibly expand and contract by 30.7% and 43.2% in volume, which indicates that the cortex PG contributes to 67.3% of a spore's volume change. The spores' and cortex PG's significant volumetric changes also lead to changes in their Young's moduli from 5.7 and 9.0 GPa at 10% RH to 0.62 and 1.2 GPa at 90% RH, respectively. Interestingly, these significant changes in the spores' and cortex PG's morphological and mechanical properties are only caused by a minute amount of the cortex PG's water exchange that occupies 28.0% of the cortex PG's volume. The cortex PG's capability in sensing and responding to environmental RH and effectively changing its structures and properties could provide insight into spores' high desiccation resistance and dormancy mechanisms.
Collapse
Affiliation(s)
- Zhi-Lun Liu
- Advanced Science Research Center (ASRC), The City University of New York, 85 St. Nicholas Terrace, New York, New York10031, United States.,Department of Chemical Engineering, The City College of New York, 275 Convent Ave., New York, New York10031, United States
| | - Xi Chen
- Advanced Science Research Center (ASRC), The City University of New York, 85 St. Nicholas Terrace, New York, New York10031, United States.,Department of Chemical Engineering, The City College of New York, 275 Convent Ave., New York, New York10031, United States.,Ph.D. Program in Physics, The Graduate Center of the City University of New York, 365 Fifth Ave., New York, New York10016, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Ave., New York, New York10016, United States
| |
Collapse
|
5
|
Mechanisms and Applications of Bacterial Sporulation and Germination in the Intestine. Int J Mol Sci 2022; 23:ijms23063405. [PMID: 35328823 PMCID: PMC8953710 DOI: 10.3390/ijms23063405] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/15/2022] [Accepted: 03/18/2022] [Indexed: 02/04/2023] Open
Abstract
Recent studies have suggested a major role for endospore forming bacteria within the gut microbiota, not only as pathogens but also as commensal and beneficial members contributing to gut homeostasis. In this review the sporulation processes, spore properties, and germination processes will be explained within the scope of the human gut. Within the gut, spore-forming bacteria are known to interact with the host’s immune system, both in vegetative cell and spore form. Together with the resistant nature of the spore, these characteristics offer potential for spores’ use as delivery vehicles for therapeutics. In the last part of the review, the therapeutic potential of spores as probiotics, vaccine vehicles, and drug delivery systems will be discussed.
Collapse
|
6
|
Andryukov BG, Karpenko AA, Lyapun IN. Learning from Nature: Bacterial Spores as a Target for Current Technologies in Medicine (Review). Sovrem Tekhnologii Med 2021; 12:105-122. [PMID: 34795986 PMCID: PMC8596247 DOI: 10.17691/stm2020.12.3.13] [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: 09/14/2019] [Indexed: 01/05/2023] Open
Abstract
The capability of some representatives of Clostridium spp. and Bacillus spp. genera to form spores in extreme external conditions long ago became a subject of medico-biological investigations. Bacterial spores represent dormant cellular forms of gram-positive bacteria possessing a high potential of stability and the capability to endure extreme conditions of their habitat. Owing to these properties, bacterial spores are recognized as the most stable systems on the planet, and spore-forming microorganisms became widely spread in various ecosystems. Spore-forming bacteria have been attracted increased interest for years due to their epidemiological danger. Bacterial spores may be in the quiescent state for dozens or hundreds of years but after they appear in the favorable conditions of a human or animal organism, they turn into vegetative forms causing an infectious process. The greatest threat among the pathogenic spore-forming bacteria is posed by the causative agents of anthrax (B. anthracis), food toxicoinfection (B. cereus), pseudomembranous colitis (C. difficile), botulism (C. botulinum), gas gangrene (C. perfringens). For the effective prevention of severe infectious diseases first of all it is necessary to study the molecular structure of bacterial spores and the biochemical mechanisms of sporulation and to develop innovative methods of detection and disinfection of dormant cells. There is another side of the problem: the necessity to investigate exo- and endospores from the standpoint of obtaining similar artificially synthesized models in order to use them in the latest medical technologies for the development of thermostable vaccines, delivery of biologically active substances to the tissues and intracellular structures. In recent years, bacterial spores have become an interesting object for the exploration from the point of view of a new paradigm of unicellular microbiology in order to study microbial heterogeneity by means of the modern analytical tools.
Collapse
Affiliation(s)
- B G Andryukov
- Leading Researcher, Laboratory of Molecular Microbiology; G.P. Somov Institute of Epidemiology and Microbiology, 1 Selskaya St., Vladivostok, 690087, Russia; Professor, Department of Fundamental Sciences; Far Eastern Federal University, 10 Village Ayaks, Island Russkiy, Vladivostok, 690922, Russia
| | - A A Karpenko
- Senior Researcher, Laboratory of Cell Biophysics; A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences, 17 Palchevskogo St., Vladivostok, 690041, Russia
| | - I N Lyapun
- Researcher, Laboratory of Molecular Microbiology G.P. Somov Institute of Epidemiology and Microbiology, 1 Selskaya St., Vladivostok, 690087, Russia
| |
Collapse
|
7
|
Performance Evaluation of Commercially Available Masks in Korea for Filtering Airborne Droplets Containing Bacteria. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18157909. [PMID: 34360199 PMCID: PMC8345791 DOI: 10.3390/ijerph18157909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 07/21/2021] [Indexed: 12/02/2022]
Abstract
The coronavirus disease (COVID-19) pandemic is a global health threat and has posed a challenge for society and social care services as well as healthcare systems. Due to the risks involved in being exposed to the virus, public health actions such as wearing masks and physical distancing are necessary to reduce its spread. However, using non-validated masks is a serious issue as such masks may provide inadequate protection against airborne bioaerosol transmission, resulting in the spread of the virus. Therefore, it is necessary to evaluate the filtering performances of the masks against bioaerosols as well as particulate matter (PM). Here, we evaluated the filtering performances of sixteen different masks (four brands each of woven, antidroplet, KF80, and KF94 masks) commercially available in Korea with high market shares. As a simulation of being exposed to bioaerosols and to the yellow dust commonly found in Korea, the filtration efficiency levels of the masks were tested against airborne bacteria-containing droplets and against fine dusts of different ranges of particle sizes. Their filtration efficiency levels against the droplets showed strong positive correlations, specifically Pearson correlation coefficient r values of 0.917, 0.905, and 0.894, with their efficiency levels against PM1.0, PM2.5, and PM10, respectively. The results of this study should be useful for choosing appropriate masks, including those that meet filtering performance requirements.
Collapse
|
8
|
Ugwuodo CJ, Nwagu TN. Stabilizing enzymes by immobilization on bacterial spores: A review of literature. Int J Biol Macromol 2020; 166:238-250. [PMID: 33115650 DOI: 10.1016/j.ijbiomac.2020.10.171] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 10/16/2020] [Accepted: 10/21/2020] [Indexed: 10/23/2022]
Abstract
The ever-increasing applications of enzymes are limited by the relatively poor performance in harsh processing conditions. As a result, there are constant innovations in immobilization protocols for improving biocatalyst activity and stability. Bacterial spores are cheap to generate and highly resistant to environmental stress. The spore core is sheathed by an inner membrane, the germ cell wall, the cortex, outer membrane, spore coat and in some species the exosporium. The spore surface is anion-rich, hydrophobic and contains several reactive groups capable of interacting and stabilizing enzyme molecules through electrostatic forces, hydrophobic interactions and covalent bonding. The probiotic nature of spores obtained from non-toxic bacterial species makes them suitable carriers for the enzyme immobilization, especially food-grade enzymes or those intended for therapeutic use. Immobilization on spores is by direct adsorption, covalent attachment or surface display during the sporulation phase. Hindrances to the immobilization on spore matrix include the production rates, operational instability, and reduced catalytic properties due to conformational changes in enzyme. This paper reviews bacterial spore as a heterofunctional support matrix gives reasons why probiotic bacillus spores are better options and the diverse technologies adopted for spore-enzyme immobilization. It further suggests directions for future use and discusses the commercialization prospects.
Collapse
|
9
|
Fu Y, Liang L, Deng S, Wu Y, Yuan Y, Gao M. Novel spore lytic enzyme from a Bacillus phage leading to spore killing. Enzyme Microb Technol 2020; 142:109698. [PMID: 33220860 DOI: 10.1016/j.enzmictec.2020.109698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 01/03/2023]
Abstract
Bacterial spores maintain metabolic dormancy and have high resistance to external pressure. Germination requires degradation of the spore cortex and the participation of germination-specific cortex-lytic enzymes (GSLEs). Previously reported GSLEs have been identified in bacteria and facilitate germination. In this study, we have characterized a novel spore lytic enzyme, Ply67, from Bacillus pumilus phage vB_BpuM_BpSp. Ply67 had a similar cortex-lytic activity to GSLEs but disrupted the inner membranes (IMs) of spores, leading to spore killing rather than germination. The amino acid sequence of the complete protein, Ply67FL, exhibited 40% homology to the GSLE SleB. Domain prediction showed that Ply67FL was composed of three domains: a signal peptide, N-terminal domain protein and C-terminal domain protein. Ply67FL rapidly caused E. coli cells lysis when it was expressed in E. coli. The protein containing the C-terminal domain protein, Ply67C, could kill B. pumilus spores. The protein containing the N-terminal domain protein, Ply67N, could combine with the decoated B. pumilus spores, indicating that N-terminal was the binding domain and C-terminal was the hydrolase domain. The protein lacking the signal peptide but containing the N-terminal and C-terminal domain proteins, Ply67, had activity against spores of various Bacillus species. The surface of spores treated with Ply67 shrank and the permeability barrier was disrupted, and the inner contents leaked out. Immunoelectron microscopic observation showed that Ply67 was mainly acted on the spore cortex. Overall, Ply67 is a novel spore lytic enzyme that differs from other GSLEs not only in amino acid sequence but also in activity against spores, and Ply67 might have the potential to kill spores of pathogenic Bacillus species, e.g., B. cereus and B. anthracis.
Collapse
Affiliation(s)
- Yajuan Fu
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100039, PR China
| | - Leiqin Liang
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100039, PR China
| | - Sangsang Deng
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100039, PR China
| | - Yan Wu
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China
| | - Yihui Yuan
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China
| | - Meiying Gao
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China.
| |
Collapse
|
10
|
Ziegler I, Vollmar P, Knüpfer M, Braun P, Stoecker K. Reevaluating limits of detection of 12 lateral flow immunoassays for the detection of Yersinia pestis, Francisella tularensis, and Bacillus anthracis spores using viable risk group-3 strains. J Appl Microbiol 2020; 130:1173-1180. [PMID: 32970936 DOI: 10.1111/jam.14863] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/28/2020] [Accepted: 09/17/2020] [Indexed: 11/27/2022]
Abstract
AIM Rapid detection of biological agents in biodefense is critical for operational, tactical and strategic levels as well as for medical countermeasures. Yersinia pestis, Francisella tularensis, and Bacillus anthracis are high priority agents of biological warfare or bioterrorism and many response forces use lateral flow assays (LFAs) for their detection. Several companies produce these assays, which offer results in short time and are easy to use. Despite their importance, only few publications on the limits of detection (LOD) for LFAs are available. Most of these studies used inactivated bacteria or risk group-2 strains. As the inactivation process in previous studies might have affected the tests' performances, it was our aim in this study to determine and compare the LOD of several commercially available LFAs using viable risk group-3 strains. METHODS AND RESULTS Lateral flow assays from four different companies for the detection of following bacteria were evaluated: Y. pestis, F. tularensis and B. anthracis spores. Two independent quantification methods for each target organism were applied, in order to ensure high quantification accuracy. LODs varied greatly between tests and organisms and ranged between 104 for Y. pestis-tests and as high as >109 for one B. anthracis-test. CONCLUSION This work precisely determined the LODs of LFAs from four commercial suppliers. The herein determined LODs differed from results of previous studies. This illustrates the need for using accurately quantified viable risk group 3-strains for determining such LODs. SIGNIFICANCE AND IMPACT OF THE STUDY Our work bridges an important knowledge gap with regard to LFA LOD. The LODs determined in this study will facilitate better assessment of LFA-results. They illustrate that a negative LFA result is not suited to exclude the presence of the respective agent in the analyzed sample.
Collapse
Affiliation(s)
- I Ziegler
- Bundeswehr Institute for Microbiology, Munich, Germany
| | - P Vollmar
- Bundeswehr Institute for Microbiology, Munich, Germany
| | - M Knüpfer
- Bundeswehr Institute for Microbiology, Munich, Germany
| | - P Braun
- Bundeswehr Institute for Microbiology, Munich, Germany
| | - K Stoecker
- Bundeswehr Institute for Microbiology, Munich, Germany
| |
Collapse
|
11
|
Guo A, Shieh YC, Wang RR. Features of material surfaces affecting virus adhesion as determined by nanoscopic quantification. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125109] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
12
|
Genes under positive selection in the core genome of pathogenic Bacillus cereus group members. INFECTION GENETICS AND EVOLUTION 2018; 65:55-64. [PMID: 30006047 DOI: 10.1016/j.meegid.2018.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 07/06/2018] [Accepted: 07/07/2018] [Indexed: 11/24/2022]
Abstract
In this comparative genomics study our aim was to unravel genes under positive selection in the core genome of the Bacillus cereus group. Indeed, the members of this group share close genetic relationships but display a rather large phenotypic and ecological diversity, providing a unique opportunity for studying how genomic changes reflect ecological adaptation during the divergence of a bacterial group. For this purpose, we screened ten completely sequenced genomes of four pathogenic Bacillus species, finding that 254 out of 3093 genes have codon sites with dN/dS (ω) values above one. These results remained unchanged after having disentangled the confounding effects of recombination and selection signature in a Bayesian framework. The presumably adaptive nucleotide polymorphisms are distributed over a wide range of biological functions, such as antibiotic resistance, DNA repair, nutrient uptake, metabolism, cell wall assembly and spore structure. Our results indicate that adaptation to animal hosts, whether as pathogens, saprophytes or symbionts, is the major driving force in the evolution of the Bacillus cereus group. Future work should seek to understand the evolutionary dynamics of both core and accessory genes in an integrative framework to ultimately unravel the key networks involved in host adaptation.
Collapse
|
13
|
Abstract
Spores of Clostridiales and Bacillales are encased in a complex series of concentric shells that provide protection, facilitate germination, and mediate interactions with the environment. Analysis of diverse spore-forming species by thin-section transmission electron microscopy reveals that the number and morphology of these encasing shells vary greatly. In some species, they appear to be composed of a small number of discrete layers. In other species, they can comprise multiple, morphologically complex layers. In addition, spore surfaces can possess elaborate appendages. For all their variability, there is a consistent architecture to the layers encasing the spore. A hallmark of all Clostridiales and Bacillales spores is the cortex, a layer made of peptidoglycan. In close association with the cortex, all species examined possess, at a minimum, a series of proteinaceous layers, called the coat. In some species, including Bacillus subtilis, only the coat is present. In other species, including Bacillus anthracis, an additional layer, called the exosporium, surrounds the coat. Our goals here are to review the present understanding of the structure, composition, assembly, and functions of the coat, primarily in the model organism B. subtilis, but also in the small but growing number of other spore-forming species where new data are showing that there is much to be learned beyond the relatively well-developed basis of knowledge in B. subtilis. To help summarize this large field and define future directions for research, we will focus on key findings in recent years.
Collapse
|
14
|
Abstract
To survive adverse conditions, some bacterial species are capable of developing into a cell type, the "spore," which exhibits minimal metabolic activity and remains viable in the presence of multiple environmental challenges. For some pathogenic bacteria, this developmental state serves as a means of survival during transmission from one host to another. Spores are the highly infectious form of these bacteria. Upon entrance into a host, specific signals facilitate germination into metabolically active replicating organisms, resulting in disease pathogenesis. In this article, we will review spore structure and function in well-studied pathogens of two genera, Bacillus and Clostridium, focusing on Bacillus anthracis and Clostridium difficile, and explore current data regarding the lifestyles of these bacteria outside the host and transmission from one host to another.
Collapse
|
15
|
Edlund AF, Zheng Q, Lowe N, Kuseryk S, Ainsworth KL, Lyles RH, Sibener SJ, Preuss D. Pollen from Arabidopsis thaliana and other Brassicaceae are functionally omniaperturate. AMERICAN JOURNAL OF BOTANY 2016; 103:1006-19. [PMID: 27335390 DOI: 10.3732/ajb.1600031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 05/23/2016] [Indexed: 05/06/2023]
Abstract
PREMISE OF THE STUDY Most pollen walls are interrupted by apertures, thin areas providing access to stigmatic fluids and exit points for pollen tubes. Unexpectedly, pollen tubes of Arabidopsis thaliana are not obligated to pass through apertures and can instead take the shortest route into the stigma, passing directly through a nonaperturate wall. METHODS We used stains and confocal microscopy to follow early pollen tube formation in A. thaliana and 200+ other species. We germinated pollen in vitro and in situ (at control and high humidities) and also used atomic force microscopy to assay material properties of nonaperture and aperture walls. KEY RESULTS Pollen tubes of A. thaliana breached nonaperture walls despite these being an order of magnitude stiffer than aperture walls. Breakout was associated with localized swelling of the pectin-rich (alcian blue positive) intine. The precision of pollen tube exit at the pollen-stigma interface was lost at high humidity. Pollen from ∼4% of the species surveyed exhibited breakout germination behavior; all nine breakout species identified so far are in the Brassicaceae family (∼25% of the Brassicaceae sampled) and are scattered across seven tribes. CONCLUSIONS The polarity of pollen germination in A. thaliana is externally induced, not linked to aperture location. The biomechanical force for breaking nonaperture walls is found in localized swelling of intine pectins. As such, the pollen from A. thaliana, and likely many Brassicaceae family members, are functionally omniaperturate. This new mechanism for germination between extant apertures raises questions about exine porosity and the diversity of mechanisms across taxa.
Collapse
Affiliation(s)
- Anna F Edlund
- Biology Department, Lafayette College, Easton, Pennsylvania 18042 USA
| | - Qin Zheng
- The James Franck Institute and Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637 USA
| | - Nancy Lowe
- Biology Department, Spelman College, 350 Spelman Lane, Atlanta, Georgia 30314 USA
| | - Skye Kuseryk
- Biology Department, Lafayette College, Easton, Pennsylvania 18042 USA
| | - Krystle L Ainsworth
- Biology Department, Spelman College, 350 Spelman Lane, Atlanta, Georgia 30314 USA
| | - Robert H Lyles
- Biostatistics Department, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322 USA
| | - Steven J Sibener
- The James Franck Institute and Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637 USA
| | - Daphne Preuss
- Molecular Genetics and Cell Biology Department, University of Chicago, Chicago, Illinois 60637 USA
| |
Collapse
|
16
|
Nanomechanical Characterization of Bacillus anthracis Spores by Atomic Force Microscopy. Appl Environ Microbiol 2016; 82:2988-2999. [PMID: 26969703 DOI: 10.1128/aem.00431-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 03/04/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The study of structures and properties of bacterial spores is important to understanding spore formation and biological responses to environmental stresses. While significant progress has been made over the years in elucidating the multilayer architecture of spores, the mechanical properties of the spore interior are not known. Here, we present a thermal atomic force microscopy (AFM) study of the nanomechanical properties of internal structures of Bacillus anthracis spores. We developed a nanosurgical sectioning method in which a stiff diamond AFM tip was used to cut an individual spore, exposing its internal structure, and a soft AFM tip was used to image and characterize the spore interior on the nanometer scale. We observed that the elastic modulus and adhesion force, including their thermal responses at elevated temperatures, varied significantly in different regions of the spore section. Our AFM images indicated that the peptidoglycan (PG) cortex of Bacillus anthracis spores consisted of rod-like nanometer-sized structures that are oriented in the direction perpendicular to the spore surface. Our findings may shed light on the spore architecture and properties. IMPORTANCE A nanosurgical AFM method was developed that can be used to probe the structure and properties of the spore interior. The previously unknown ultrastructure of the PG cortex of Bacillus anthracis spores was observed to consist of nanometer-sized rod-like structures that are oriented in the direction perpendicular to the spore surface. The variations in the nanomechanical properties of the spore section were largely correlated with its chemical composition. Different components of the spore materials showed different thermal responses at elevated temperatures.
Collapse
|
17
|
Ghio S, Insani EM, Piccinni FE, Talia PM, Grasso DH, Campos E. GH10 XynA is the main xylanase identified in the crude enzymatic extract of Paenibacillus sp. A59 when grown on xylan or lignocellulosic biomass. Microbiol Res 2016; 186-187:16-26. [DOI: 10.1016/j.micres.2016.02.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 02/23/2016] [Accepted: 02/29/2016] [Indexed: 12/15/2022]
|
18
|
Headd B, Bradford SA. Use of aerobic spores as a surrogate for cryptosporidium oocysts in drinking water supplies. WATER RESEARCH 2016; 90:185-202. [PMID: 26734779 DOI: 10.1016/j.watres.2015.12.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 12/10/2015] [Accepted: 12/13/2015] [Indexed: 05/06/2023]
Abstract
Waterborne illnesses are a growing concern among health and regulatory agencies worldwide. The United States Environmental Protection Agency has established several rules to combat the contamination of water supplies by cryptosporidium oocysts, however, the detection and study of cryptosporidium oocysts is hampered by methodological and financial constraints. As a result, numerous surrogates for cryptosporidium oocysts have been proposed by the scientific community and efforts are underway to evaluate many of the proposed surrogates. The purpose of this review is to evaluate the suitability of aerobic bacterial spores to serve as a surrogate for cryptosporidium oocysts in identifying contaminated drinking waters. To accomplish this we present a comparison of the biology and life cycles of aerobic spores and oocysts and compare their physical properties. An analysis of their surface properties is presented along with a review of the literature in regards to the transport, survival, and prevalence of aerobic spores and oocysts in the saturated subsurface environment. Aerobic spores and oocysts share many commonalities with regard to biology and survivability, and the environmental prevalence and ease of detection make aerobic spores a promising surrogate for cryptosporidium oocysts in surface and groundwater. However, the long-term transport and release of aerobic spores still needs to be further studied, and compared with available oocyst information. In addition, the surface properties and environmental interactions of spores are known to be highly dependent on the spore taxa and purification procedures, and additional research is needed to address these issues in the context of transport.
Collapse
Affiliation(s)
- Brendan Headd
- U.S. Salinity Lab USDA, ARS, 450 W. Big Springs Road, Riverside, CA 92507-4617, USA
| | - Scott A Bradford
- U.S. Salinity Lab USDA, ARS, 450 W. Big Springs Road, Riverside, CA 92507-4617, USA.
| |
Collapse
|
19
|
WANG CONGZHOU, STANCIU CRISTINA, EHRHARDT CHRISTOPHERJ, YADAVALLI VAMSIK. Morphological and mechanical imaging of Bacillus cereus
spore formation at the nanoscale. J Microsc 2015; 258:49-58. [DOI: 10.1111/jmi.12214] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 12/11/2014] [Indexed: 11/30/2022]
Affiliation(s)
- CONGZHOU WANG
- Department of Chemical and Life Science Engineering; Virginia Commonwealth University; Richmond Virginia 23284 U.S.A
| | - CRISTINA STANCIU
- Department of Forensic Science; Virginia Commonwealth University; Richmond Virginia 23284 U.S.A
| | - CHRISTOPHER J. EHRHARDT
- Department of Forensic Science; Virginia Commonwealth University; Richmond Virginia 23284 U.S.A
| | - VAMSI K. YADAVALLI
- Department of Chemical and Life Science Engineering; Virginia Commonwealth University; Richmond Virginia 23284 U.S.A
| |
Collapse
|
20
|
Rusciano G, Zito G, Isticato R, Sirec T, Ricca E, Bailo E, Sasso A. Nanoscale chemical imaging of Bacillus subtilis spores by combining tip-enhanced Raman scattering and advanced statistical tools. ACS NANO 2014; 8:12300-12309. [PMID: 25415422 DOI: 10.1021/nn504595k] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Tip-enhanced Raman Scattering (TERS) has recently emerged as a powerful spectroscopic technique capable of providing subdiffraction morphological and chemical information on samples. In this work, we apply TERS spectroscopy for surface analysis of the Bacillus subtilis spore, a very attractive biosystem for a wide range of applications regulated by the spore surface properties. The observed spectra reflect the complex and heterogeneous environment explored by the plasmonic tip, therefore exhibiting significant point-to-point variations at the nanoscale. Herein, we demonstrate that TERS data processing via principal component analysis allows handling such spectral changes, thus enabling an unbiased correlative imaging based on TERS. Our experimental outcomes suggest a denser arrangement of both proteins and carbohydrates on specific spore surface regions simultaneously revealed by AFM phase imaging. Successful TERS analysis of spores' surface is useful for bacterial surface-display systems and drug delivery applications.
Collapse
Affiliation(s)
- Giulia Rusciano
- Department of Physics and ‡Department of Biology, University of Naples Federico II , via Cintia, 80126-I Naples, Italy
| | | | | | | | | | | | | |
Collapse
|
21
|
Plomp M, Carroll AM, Setlow P, Malkin AJ. Architecture and assembly of the Bacillus subtilis spore coat. PLoS One 2014; 9:e108560. [PMID: 25259857 PMCID: PMC4178626 DOI: 10.1371/journal.pone.0108560] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 08/28/2014] [Indexed: 11/30/2022] Open
Abstract
Bacillus spores are encased in a multilayer, proteinaceous self-assembled coat structure that assists in protecting the bacterial genome from stresses and consists of at least 70 proteins. The elucidation of Bacillus spore coat assembly, architecture, and function is critical to determining mechanisms of spore pathogenesis, environmental resistance, immune response, and physicochemical properties. Recently, genetic, biochemical and microscopy methods have provided new insight into spore coat architecture, assembly, structure and function. However, detailed spore coat architecture and assembly, comprehensive understanding of the proteomic composition of coat layers, and specific roles of coat proteins in coat assembly and their precise localization within the coat remain in question. In this study, atomic force microscopy was used to probe the coat structure of Bacillus subtilis wild type and cotA, cotB, safA, cotH, cotO, cotE, gerE, and cotE gerE spores. This approach provided high-resolution visualization of the various spore coat structures, new insight into the function of specific coat proteins, and enabled the development of a detailed model of spore coat architecture. This model is consistent with a recently reported four-layer coat assembly and further adds several coat layers not reported previously. The coat is organized starting from the outside into an outermost amorphous (crust) layer, a rodlet layer, a honeycomb layer, a fibrous layer, a layer of “nanodot” particles, a multilayer assembly, and finally the undercoat/basement layer. We propose that the assembly of the previously unreported fibrous layer, which we link to the darkly stained outer coat seen by electron microscopy, and the nanodot layer are cotH- and cotE- dependent and cotE-specific respectively. We further propose that the inner coat multilayer structure is crystalline with its apparent two-dimensional (2D) nuclei being the first example of a non-mineral 2D nucleation crystallization pattern in a biological organism.
Collapse
Affiliation(s)
- Marco Plomp
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Alicia Monroe Carroll
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, United States of America
- * E-mail: (PS); (AJM)
| | - Alexander J. Malkin
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
- * E-mail: (PS); (AJM)
| |
Collapse
|
22
|
Gu J, Yang R, Hua X, Zhang W, Zhao W. Adsorption-based immobilization ofCaldicellulosiruptor saccharolyticuscellobiose 2-epimerase onBacillus subtilisspores. Biotechnol Appl Biochem 2014; 62:237-44. [DOI: 10.1002/bab.1262] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 06/11/2014] [Indexed: 12/20/2022]
Affiliation(s)
- Junyan Gu
- State Key Laboratory of Food Science and Technology; Jiangnan University; Wuxi People's Republic of China
- School of Food Science and Technology; Jiangnan University; Wuxi People's Republic of China
| | - Ruijin Yang
- State Key Laboratory of Food Science and Technology; Jiangnan University; Wuxi People's Republic of China
- School of Food Science and Technology; Jiangnan University; Wuxi People's Republic of China
| | - Xiao Hua
- State Key Laboratory of Food Science and Technology; Jiangnan University; Wuxi People's Republic of China
- School of Food Science and Technology; Jiangnan University; Wuxi People's Republic of China
| | - Wenbin Zhang
- School of Food Science and Technology; Jiangnan University; Wuxi People's Republic of China
| | - Wei Zhao
- School of Food Science and Technology; Jiangnan University; Wuxi People's Republic of China
| |
Collapse
|
23
|
Tan IS, Ramamurthi KS. Spore formation in Bacillus subtilis. ENVIRONMENTAL MICROBIOLOGY REPORTS 2014; 6:212-25. [PMID: 24983526 PMCID: PMC4078662 DOI: 10.1111/1758-2229.12130] [Citation(s) in RCA: 223] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 11/05/2013] [Accepted: 11/19/2013] [Indexed: 05/04/2023]
Abstract
Although prokaryotes ordinarily undergo binary fission to produce two identical daughter cells, some are able to undergo alternative developmental pathways that produce daughter cells of distinct cell morphology and fate. One such example is a developmental programme called sporulation in the bacterium Bacillus subtilis, which occurs under conditions of environmental stress. Sporulation has long been used as a model system to help elucidate basic processes of developmental biology including transcription regulation, intercellular signalling, membrane remodelling, protein localization and cell fate determination. This review highlights some of the recent work that has been done to further understand prokaryotic cell differentiation during sporulation and its potential applications.
Collapse
Affiliation(s)
- Irene S Tan
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA; NIH-Johns Hopkins University Graduate Partnerships Program, Baltimore, MD, 21218, USA
| | | |
Collapse
|
24
|
Sella SRBR, Vandenberghe LPS, Soccol CR. Life cycle and spore resistance of spore-forming Bacillus atrophaeus. Microbiol Res 2014; 169:931-9. [PMID: 24880805 DOI: 10.1016/j.micres.2014.05.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Revised: 04/29/2014] [Accepted: 05/04/2014] [Indexed: 12/28/2022]
Abstract
Bacillus endospores have a wide variety of important medical and industrial applications. This is an overview of the fundamental aspects of the life cycle, spore structure and factors that influence the spore resistance of spore-forming Bacillus. Bacillus atrophaeus was used as reference microorganism for this review because their spores are widely used to study spore resistance and morphology. Understanding the mechanisms involved in the cell cycle and spore survival is important for developing strategies for spore killing; producing highly resistant spores for biodefense, food and pharmaceutical applications; and developing new bioactive molecules and methods for spore surface display.
Collapse
Affiliation(s)
- Sandra R B R Sella
- Production and Research Centre of Immunobiological Products, Secretaria de Saúde do Estado do Paraná, Piraquara, PR, Brazil; Bioprocess Engineering and Biotechnology Department, Federal University of Paraná, Curitiba, PR, Brazil.
| | - Luciana P S Vandenberghe
- Bioprocess Engineering and Biotechnology Department, Federal University of Paraná, Curitiba, PR, Brazil
| | - Carlos Ricardo Soccol
- Bioprocess Engineering and Biotechnology Department, Federal University of Paraná, Curitiba, PR, Brazil
| |
Collapse
|
25
|
Xing Y, Li A, Felker DL, Burggraf LW. Nanoscale structural and mechanical analysis of Bacillus anthracis spores inactivated with rapid dry heating. Appl Environ Microbiol 2014; 80:1739-49. [PMID: 24375142 PMCID: PMC3957622 DOI: 10.1128/aem.03483-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 12/21/2013] [Indexed: 11/20/2022] Open
Abstract
Effective killing of Bacillus anthracis spores is of paramount importance to antibioterrorism, food safety, environmental protection, and the medical device industry. Thus, a deeper understanding of the mechanisms of spore resistance and inactivation is highly desired for developing new strategies or improving the known methods for spore destruction. Previous studies have shown that spore inactivation mechanisms differ considerably depending upon the killing agents, such as heat (wet heat, dry heat), UV, ionizing radiation, and chemicals. It is believed that wet heat kills spores by inactivating critical enzymes, while dry heat kills spores by damaging their DNA. Many studies have focused on the biochemical aspects of spore inactivation by dry heat; few have investigated structural damages and changes in spore mechanical properties. In this study, we have inactivated Bacillus anthracis spores with rapid dry heating and performed nanoscale topographical and mechanical analysis of inactivated spores using atomic force microscopy (AFM). Our results revealed significant changes in spore morphology and nanomechanical properties after heat inactivation. In addition, we also found that these changes were different under different heating conditions that produced similar inactivation probabilities (high temperature for short exposure time versus low temperature for long exposure time). We attributed the differences to the differential thermal and mechanical stresses in the spore. The buildup of internal thermal and mechanical stresses may become prominent only in ultrafast, high-temperature heat inactivation when the experimental timescale is too short for heat-generated vapor to efficiently escape from the spore. Our results thus provide direct, visual evidences of the importance of thermal stresses and heat and mass transfer to spore inactivation by very rapid dry heating.
Collapse
Affiliation(s)
- Yun Xing
- Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson Air Force Base (WPAFB), Dayton, Ohio, USA
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, Tennessee, USA
| | - Alex Li
- Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson Air Force Base (WPAFB), Dayton, Ohio, USA
| | - Daniel L. Felker
- Department of Systems Engineering & Management, Air Force Institute of Technology, WPAFB, Dayton, Ohio, USA
| | - Larry W. Burggraf
- Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson Air Force Base (WPAFB), Dayton, Ohio, USA
| |
Collapse
|
26
|
Bouzianas DG. Potential biological targets ofBacillus anthracisin anti-infective approaches against the threat of bioterrorism. Expert Rev Anti Infect Ther 2014; 5:665-84. [PMID: 17678429 DOI: 10.1586/14787210.5.4.665] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The terrorist attacks of 2001 involving anthrax underscore the imperative that safe and effective medical countermeasures should be readily available. Vaccination appears to be the most effective form of mass protection against a biological attack, but the current vaccines have drawbacks that justify the enormous amount of effort currently being put into developing more effective vaccines and other treatment modalities. After providing a comprehensive overview of the organism Bacillus anthracis as a biological weapon and its pathogenicity, this review briefly summarizes the current knowledge vital to the management of anthrax disease. This knowledge has been acquired since 2001 as a result of the progress on anthrax research and focuses on the possible development of improved human anti-infective strategies targeting B. anthracis spore components, as well as strategies based on host-pathogen interactions.
Collapse
Affiliation(s)
- Dimitrios G Bouzianas
- Department of Medical Laboratories, Faculty of Health and Care Professions, University-level Technological Educational Institute of Thessaloniki, Greece.
| |
Collapse
|
27
|
Bacillus thuringiensis as a surrogate for Bacillus anthracis in aerosol research. World J Microbiol Biotechnol 2013; 30:1453-61. [PMID: 24338558 DOI: 10.1007/s11274-013-1576-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 12/03/2013] [Indexed: 10/25/2022]
Abstract
Characterization of candidate surrogate spores prior to experimental use is critical to confirm that the surrogate characteristics are as closely similar as possible to those of the pathogenic agent of interest. This review compares the physical properties inherent to spores of Bacillus anthracis (Ba) and Bacillus thuringiensis (Bt) that impact their movement in air and interaction with surfaces, including size, shape, density, surface morphology, structure and hydrophobicity. Also evaluated is the impact of irradiation on the physical properties of both Bacillus species. Many physical features of Bt and Ba have been found to be similar and, while Bt is considered typically non-pathogenic, it is in the B. cereus group, as is Ba. When cultured and sporulated under similar conditions, both microorganisms share a similar cylindrical pellet shape, an aerodynamic diameter of approximately 1 μm (in the respirable size range), have an exosporium with a hairy nap, and have higher relative hydrophobicities than other Bacillus species. While spore size, morphology, and other physical properties can vary among strains of the same species, the variations can be due to growth/sporulation conditions and may, therefore, be controlled. Growth and sporulation conditions are likely among the most important factors that influence the representativeness of one species, or preparation, to another. All Bt spores may, therefore, not be representative of all Ba spores. Irradiated spores do not appear to be a good surrogate to predict the behavior of non-irradiated spores due to structural damage caused by the irradiation. While the use of Bt as a surrogate for Ba in aerosol testing appears to be well supported, this review does not attempt to narrow selection between Bt strains. Comparative studies should be performed to test the hypothesis that viable Ba and Bt spores will behave similarly when suspended in the air (as an aerosol) and to compare the known microscale characteristics versus the macroscale response.
Collapse
|
28
|
Mundra RV, Mehta KK, Wu X, Paskaleva EE, Kane RS, Dordick JS. Enzyme-drivenbacillusspore coat degradation leading to spore killing. Biotechnol Bioeng 2013; 111:654-63. [DOI: 10.1002/bit.25132] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/30/2013] [Accepted: 10/07/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Ruchir V. Mundra
- Howard P. Isermann Department of Chemical and Biological Engineering; Rensselaer Polytechnic Institute; CBIS 4005E, 110 8th Street Troy New York 12180
- Center for Biotechnology and Interdisciplinary Studies; Rensselaer Polytechnic Institute; Troy New York
| | - Krunal K. Mehta
- Howard P. Isermann Department of Chemical and Biological Engineering; Rensselaer Polytechnic Institute; CBIS 4005E, 110 8th Street Troy New York 12180
- Center for Biotechnology and Interdisciplinary Studies; Rensselaer Polytechnic Institute; Troy New York
| | - Xia Wu
- Howard P. Isermann Department of Chemical and Biological Engineering; Rensselaer Polytechnic Institute; CBIS 4005E, 110 8th Street Troy New York 12180
- Center for Biotechnology and Interdisciplinary Studies; Rensselaer Polytechnic Institute; Troy New York
| | - Elena E. Paskaleva
- Center for Biotechnology and Interdisciplinary Studies; Rensselaer Polytechnic Institute; Troy New York
| | - Ravi S. Kane
- Howard P. Isermann Department of Chemical and Biological Engineering; Rensselaer Polytechnic Institute; CBIS 4005E, 110 8th Street Troy New York 12180
- Center for Biotechnology and Interdisciplinary Studies; Rensselaer Polytechnic Institute; Troy New York
| | - Jonathan S. Dordick
- Howard P. Isermann Department of Chemical and Biological Engineering; Rensselaer Polytechnic Institute; CBIS 4005E, 110 8th Street Troy New York 12180
- Center for Biotechnology and Interdisciplinary Studies; Rensselaer Polytechnic Institute; Troy New York
- Department of Materials Science and Engineering; Rensselaer Polytechnic Institute; Troy New York
- Department of Biology; Rensselaer Polytechnic Institute; Troy New York
- Department of Biomedical Engineering; Rensselaer Polytechnic Institute; Troy New York
| |
Collapse
|
29
|
Gieseck RL, Chan BD, Savran CA. A humidity-sensitive hydrogel-Bacillus spore composite for micropatterning of biomolecular gradients. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:085003. [PMID: 24007098 DOI: 10.1063/1.4817971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A composite material consisting of Bacillus subtilis spores suspended in a humidity sensitive hydrogel can be used to pattern biomolecules in different concentrations directly onto glass surfaces using a mechanical micromanipulator. By altering the relative humidity surrounding the composite gel during deposition, surface concentration of patterned biomolecules can be controlled and varied to create user-defined, biomolecular surface concentrations.
Collapse
Affiliation(s)
- Richard L Gieseck
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | | | | |
Collapse
|
30
|
Li AG, Xing Y, Burggraf LW. Thermal effects on surface structures and properties of Bacillus anthracis spores on nanometer scales. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:8343-8354. [PMID: 23742662 DOI: 10.1021/la400992q] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Bacterial spores, one of the hardiest forms of life known, can survive severe environmental stresses such as high temperature. Using thermal atomic force microscopy (AFM), we show that the surface structures and properties of Bacillus anthracis spores when exposed to elevated temperatures undergo substantial changes on nanometer scales. Thermal-blister-like nanostructures, which grow in size with increasing temperature, are formed on the spore surface when it is heated by a thermal tip. Although thermal damage to the spore surface is persistent upon cooling heat-treated spores to room temperature, thermal effects on surface properties of the spores are complex. The thermally induced nanostructures show a lower surface-tip adhesion and a higher modulus than the surrounding spore surface. The overall trend is for the adhesion to decrease with increasing temperature. However, the adhesion of heat-treated spores may be smaller than, equal to, or larger than that of untreated spores, depending upon the degree of surface damage induced by heat. Although the overall spore dimensions show few changes during and after heat treatment, the size of the spore substructures decreases significantly. In addition, we demonstrate a nanoscratch AFM method for imaging the subsurface structures of spores.
Collapse
Affiliation(s)
- Alex G Li
- Department of Engineering Physics, Air Force Institute of Technology, 2950 Hobson Way, Wright-Patterson AFB Ohio 45433-7765, United States.
| | | | | |
Collapse
|
31
|
Jenkins SA, Xu Y. Characterization of Bacillus anthracis persistence in vivo. PLoS One 2013; 8:e66177. [PMID: 23750280 PMCID: PMC3672131 DOI: 10.1371/journal.pone.0066177] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 05/07/2013] [Indexed: 02/07/2023] Open
Abstract
Pulmonary exposure to Bacillus anthracis spores initiates inhalational anthrax, a life-threatening infection. It is known that dormant spores can be recovered from the lungs of infected animals months after the initial spore exposure. Consequently, a 60-day course antibiotic treatment is recommended for exposed individuals. However, there has been little information regarding details or mechanisms of spore persistence in vivo. In this study, we investigated spore persistence in a mouse model. The results indicated that weeks after intranasal inoculation with B. anthracis spores, substantial amounts of spores could be recovered from the mouse lung. Moreover, spores of B. anthracis were significantly better at persisting in the lung than spores of a non-pathogenic Bacillus subtilis strain. The majority of B. anthracis spores in the lung were tightly associated with the lung tissue, as they could not be readily removed by lavage. Immunofluorescence staining of lung sections showed that spores associated with the alveolar and airway epithelium. Confocal analysis indicated that some of the spores were inside epithelial cells. This was further confirmed by differential immunofluorescence staining of lung cells harvested from the infected lungs, suggesting that association with lung epithelial cells may provide an advantage to spore persistence in the lung. There was no or very mild inflammation in the infected lungs. Furthermore, spores were present in the lung tissue as single spores rather than in clusters. We also showed that the anthrax toxins did not play a role in persistence. Together, the results suggest that B. anthracis spores have special properties that promote their persistence in the lung, and that there may be multiple mechanisms contributing to spore persistence.
Collapse
Affiliation(s)
- Sarah A. Jenkins
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas, United States of America
| | - Yi Xu
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas, United States of America
- * E-mail:
| |
Collapse
|
32
|
Upadhyayula S, Lam S, Ha A, Malik-Chaudhry HK, Vullev VI. Dynamic staining of Bacillus endospores with Thioflavin T. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:499-502. [PMID: 23365938 DOI: 10.1109/embc.2012.6345977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Rapid detection and identification of endospores presents a range of complex challenges. Dynamic staining approach, developed in our lab, utilizes the time-course fluorescence enhancement of an amyloid-staining dye, Thioflavin T (ThT), after mixing with intact endospores. We examined the kinetics of staining Bacillus atrophaeus and Bacillus thuringiensis endospores, and the rates of staining were different for the two bacilli when intact endospores were treated with ThT. This finding demonstrates an avenue for attaining information about the sporulated bacterial species without lysing, germinating or other pretreatment steps.
Collapse
Affiliation(s)
- Srigokul Upadhyayula
- Department of Biochemistry, Department of Bioengineering and Center for Bioengineering Research, University of California, Riverside, CA 92521, USA.
| | | | | | | | | |
Collapse
|
33
|
Chen SC, Wu PH, Su YC, Wen TN, Wei YS, Wang NC, Hsu CA, Wang AHJ, Shyur LF. Biochemical characterization of a novel laccase from the basidiomycete fungus Cerrena sp. WR1. Protein Eng Des Sel 2012; 25:761-9. [PMID: 23081836 DOI: 10.1093/protein/gzs082] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This study reports a new white-rot fungus Cerrena sp. WR1, identified based on an 18S rDNA sequence, which can secrete extracellular forms of laccase with a maximal activity reaching 202 000 U l⁻¹ in a 5-l fermenter. A laccase protein, designated Lcc3, was purified and shown to be N-linked glycosylated by PNGase F and liquid chromatography tandem mass spectrometry analyses. The respective full-length cDNA gene (lcc3) of the Lcc3 protein was obtained using polymerase chain reaction-based methods. Kinetic studies showed that the K(m) and k(cat) of the native Lcc3 were 3.27 μM and 934.6 s⁻¹ for 2,2'-Azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid), 849.1 μM and 147.9 s⁻¹ for guaiacol, 392.7 μM and 109.2 s⁻¹ for 2,6-dimethoxyphenol, and 881 μM and 115.5 s⁻¹ for catechol, respectively. The T(m) of Lcc3 was determined at 73.9°C and it showed a long t(½) (120 min) at 50°C. The laccase was highly ethanol resistant, with 80% of its original activity was detected when incubated in 25% ethanol for 14 days. Furthermore, crude enzyme broth or Lcc3 could degrade lignin in kraft paper (26.5%), and showed high decoloration efficiency (90%) on synthetic dye Remazol Brilliant Blue R. Together, these data demonstrate that Cerrena sp. WR1 Lcc3 possesses novel biochemical and kinetic properties that may aid its application in industry.
Collapse
Affiliation(s)
- Sheng-Chung Chen
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan, ROC
| | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Effect of pH on the electrophoretic mobility of spores of Bacillus anthracis and its surrogates in aqueous solutions. Appl Environ Microbiol 2012; 78:8470-3. [PMID: 23001659 DOI: 10.1128/aem.01337-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The electrophoretic mobility (EPM) of endospores of Bacillus anthracis and surrogates was measured in aqueous solution across a broad pH range and several ionic strengths. EPM values trended around phylogenetic clustering based on the 16S rRNA gene. Measurements reported here provide new insight for Bacillus anthracis surrogate selection and for attachment/detachment and transport studies.
Collapse
|
35
|
Sahin O, Yong EH, Driks A, Mahadevan L. Physical basis for the adaptive flexibility of Bacillus spore coats. J R Soc Interface 2012; 9:3156-60. [PMID: 22859568 DOI: 10.1098/rsif.2012.0470] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Bacillus spores are highly resistant dormant cells formed in response to starvation. The spore is surrounded by a structurally complex protein shell, the coat, which protects the genetic material. In spite of its dormancy, once nutrient is available (or an appropriate physical stimulus is provided) the spore is able to resume metabolic activity and return to vegetative growth, a process requiring the coat to be shed. Spores dynamically expand and contract in response to humidity, demanding that the coat be flexible. Despite the coat's critical biological functions, essentially nothing is known about the design principles that allow the coat to be tough but also flexible and, when metabolic activity resumes, to be efficiently shed. Here, we investigated the hypothesis that these apparently incompatible characteristics derive from an adaptive mechanical response of the coat. We generated a mechanical model predicting the emergence and dynamics of the folding patterns uniformly seen in Bacillus spore coats. According to this model, spores carefully harness mechanical instabilities to fold into a wrinkled pattern during sporulation. Owing to the inherent nonlinearity in their formation, these wrinkles persist during dormancy and allow the spore to accommodate changes in volume without compromising structural and biochemical integrity. This characteristic of the spore and its coat may inspire design of adaptive materials.
Collapse
Affiliation(s)
- Ozgur Sahin
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA.
| | | | | | | |
Collapse
|
36
|
Sella SRBR, Guizelini BP, Gouvea PM, Figueiredo LFM, Ribeiro CAO, Vandenberghe LPS, Minozzo JC, Soccol CR. Relations between phenotypic changes of spores and biofilm production by Bacillus atrophaeus ATCC 9372 growing in solid-state fermentation. Arch Microbiol 2012; 194:815-25. [DOI: 10.1007/s00203-012-0815-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 03/11/2012] [Accepted: 04/06/2012] [Indexed: 11/30/2022]
|
37
|
Fiester SE, Helfinstine SL, Redfearn JC, Uribe RM, Woolverton CJ. Electron beam irradiation dose dependently damages the bacillus spore coat and spore membrane. Int J Microbiol 2012; 2012:579593. [PMID: 22319535 PMCID: PMC3272845 DOI: 10.1155/2012/579593] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 10/13/2011] [Accepted: 10/14/2011] [Indexed: 12/30/2022] Open
Abstract
Effective control of spore-forming bacilli begs suitable physical or chemical methods. While many spore inactivation techniques have been proven effective, electron beam (EB) irradiation has been frequently chosen to eradicate Bacillus spores. Despite its widespread use, there are limited data evaluating the effects of EB irradiation on Bacillus spores. To study this, B. atrophaeus spores were purified, suspended in sterile, distilled water, and irradiated with EB (up to 20 kGy). Irradiated spores were found (1) to contain structural damage as observed by electron microscopy, (2) to have spilled cytoplasmic contents as measured by spectroscopy, (3) to have reduced membrane integrity as determined by fluorescence cytometry, and (4) to have fragmented genomic DNA as measured by gel electrophoresis, all in a dose-dependent manner. Additionally, cytometry data reveal decreased spore size, increased surface alterations, and increased uptake of propidium iodide, with increasing EB dose, suggesting spore coat alterations with membrane damage, prior to loss of spore viability. The present study suggests that EB irradiation of spores in water results in substantial structural damage of the spore coat and inner membrane, and that, along with DNA fragmentation, results in dose-dependent spore inactivation.
Collapse
Affiliation(s)
- S. E. Fiester
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - S. L. Helfinstine
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - J. C. Redfearn
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - R. M. Uribe
- College of Technology, Kent State University, Kent, OH 44242, USA
| | - C. J. Woolverton
- College of Public Health, Kent State University, Kent, OH 44242, USA
| |
Collapse
|
38
|
Qiao H, Krajcikova D, Liu C, Li Y, Wang H, Barak I, Tang J. The Interactions of Spore-Coat Morphogenetic Proteins Studied by Single-Molecule Recognition Force Spectroscopy. Chem Asian J 2012; 7:725-31. [DOI: 10.1002/asia.201100795] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Indexed: 11/08/2022]
|
39
|
|
40
|
Tomasula PM, Mukhopadhyay S, Datta N, Porto-Fett A, Call JE, Luchansky JB, Renye J, Tunick M. Pilot-scale crossflow-microfiltration and pasteurization to remove spores of Bacillus anthracis (Sterne) from milk. J Dairy Sci 2011; 94:4277-91. [PMID: 21854901 DOI: 10.3168/jds.2010-3879] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 04/18/2011] [Indexed: 11/19/2022]
Abstract
High-temperature, short-time pasteurization of milk is ineffective against spore-forming bacteria such as Bacillus anthracis (BA), but is lethal to its vegetative cells. Crossflow microfiltration (MF) using ceramic membranes with a pore size of 1.4 μm has been shown to reject most microorganisms from skim milk; and, in combination with pasteurization, has been shown to extend its shelf life. The objectives of this study were to evaluate MF for its efficiency in removing spores of the attenuated Sterne strain of BA from milk; to evaluate the combined efficiency of MF using a 0.8-μm ceramic membrane, followed by pasteurization (72°C, 18.6s); and to monitor any residual BA in the permeates when stored at temperatures of 4, 10, and 25°C for up to 28 d. In each trial, 95 L of raw skim milk was inoculated with about 6.5 log(10) BA spores/mL of milk. It was then microfiltered in total recycle mode at 50°C using ceramic membranes with pore sizes of either 0.8 μm or 1.4 μm, at crossflow velocity of 6.2 m/s and transmembrane pressure of 127.6 kPa, conditions selected to exploit the selectivity of the membrane. Microfiltration using the 0.8-μm membrane removed 5.91±0.05 log(10) BA spores/mL of milk and the 1.4-μm membrane removed 4.50±0.35 log(10) BA spores/mL of milk. The 0.8-μm membrane showed efficient removal of the native microflora and both membranes showed near complete transmission of the casein proteins. Spore germination was evident in the permeates obtained at 10, 30, and 120 min of MF time (0.8-μm membrane) but when stored at 4 or 10°C, spore levels were decreased to below detection levels (≤0.3 log(10) spores/mL) by d 7 or 3 of storage, respectively. Permeates stored at 25°C showed coagulation and were not evaluated further. Pasteurization of the permeate samples immediately after MF resulted in additional spore germination that was related to the length of MF time. Pasteurized permeates obtained at 10 min of MF and stored at 4 or 10°C showed no growth of BA by d 7 and 3, respectively. Pasteurization of permeates obtained at 30 and 120 min of MF resulted in spore germination of up to 2.42 log(10) BA spores/mL. Spore levels decreased over the length of the storage period at 4 or 10°C for the samples obtained at 30 min of MF but not for the samples obtained at 120 min of MF. This study confirms that MF using a 0.8-μm membrane before high-temperature, short-time pasteurization may improve the safety and quality of the fluid milk supply; however, the duration of MF should be limited to prevent spore germination following pasteurization.
Collapse
Affiliation(s)
- P M Tomasula
- Dairy and Functional Foods Research Unit, USDA, ARS, Eastern Regional Research Center, Wyndmoor, PA 19038, USA.
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Lee I, Chung E, Kweon H, Yiacoumi S, Tsouris C. Scanning surface potential microscopy of spore adhesion on surfaces. Colloids Surf B Biointerfaces 2011; 92:271-6. [PMID: 22196463 DOI: 10.1016/j.colsurfb.2011.11.052] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 10/05/2011] [Accepted: 11/30/2011] [Indexed: 11/30/2022]
Abstract
The adhesion of spores of Bacillus anthracis - the cause of anthrax and a likely biological threat - to solid surfaces is an important consideration in cleanup after an accidental or deliberate release. However, because of safety concerns, directly studying B. anthracis spores with advanced instrumentation is problematic. As a first step, we are examining the electrostatic potential of Bacillus thuringiensis (Bt), which is a closely related species that is often used as a simulant to study B. anthracis. Scanning surface potential microscopy (SSPM), also known as Kelvin probe force microscopy (KPFM), was used to investigate the influence of relative humidity (RH) on the surface electrostatic potential of Bt that had adhered to silica, mica, or gold substrates. AFM/SSPM side-by-side images were obtained separately in air, at various values of RH, after an aqueous droplet with spores was applied on each surface and allowed to dry before measurements. In the SSPM images, a negative potential on the surface of the spores was observed compared with that of the substrates. The surface potential decreased as the humidity increased. Spores were unable to adhere to a surface with an extremely negative potential, such as mica.
Collapse
Affiliation(s)
- I Lee
- Department of Electrical Engineering & Computer Science, University of Tennessee, Knoxville, TN 37996, United States.
| | | | | | | | | |
Collapse
|
42
|
Surface architecture of endospores of the Bacillus cereus/anthracis/thuringiensis family at the subnanometer scale. Proc Natl Acad Sci U S A 2011; 108:16014-9. [PMID: 21896762 DOI: 10.1073/pnas.1109419108] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bacteria of the Bacillus cereus family form highly resistant spores, which in the case of the pathogen B. anthracis act as the agents of infection. The outermost layer, the exosporium, enveloping spores of the B. cereus family as well as a number of Clostridia, plays roles in spore adhesion, dissemination, targeting, and germination control. We have analyzed two naturally crystalline layers associated with the exosporium, one representing the "basal" layer to which the outermost spore layer ("hairy nap") is attached, and the other likely representing a subsurface ("parasporal") layer. We have used electron cryomicroscopy at a resolution of 0.8-0.6 nm and circular dichroism spectroscopic measurements to reveal a highly α-helical structure for both layers. The helices are assembled into 2D arrays of "cups" or "crowns." High-resolution atomic force microscopy of the outermost layer showed that the open ends of these cups face the external environment and the highly immunogenic collagen-like fibrils of the hairy nap (BclA) are attached to this surface. Based on our findings, we present a molecular model for the spore surface and propose how this surface can act as a semipermeable barrier and a matrix for binding of molecules involved in defense, germination control, and other interactions of the spore with the environment.
Collapse
|
43
|
Kramer MA, Gieseck RL, Andrews B, Ivanisevic A. Spore-Terminated Cantilevers for Chemical Patterning on Complex Architectures. J Am Chem Soc 2011; 133:9627-9. [PMID: 21619041 DOI: 10.1021/ja201331j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marcus A. Kramer
- Weldon School of Biomedical Engineering, ‡Department of Biochemistry, and §Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Richard L. Gieseck
- Weldon School of Biomedical Engineering, ‡Department of Biochemistry, and §Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Benjamin Andrews
- Weldon School of Biomedical Engineering, ‡Department of Biochemistry, and §Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Albena Ivanisevic
- Weldon School of Biomedical Engineering, ‡Department of Biochemistry, and §Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| |
Collapse
|
44
|
Adsorption immobilization of Escherichia coli phytase on probiotic Bacillus polyfermenticus spores. Enzyme Microb Technol 2011; 49:66-71. [DOI: 10.1016/j.enzmictec.2011.03.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 01/13/2011] [Accepted: 03/17/2011] [Indexed: 11/22/2022]
|
45
|
Nguyen Thi Minh H, Durand A, Loison P, Perrier-Cornet JM, Gervais P. Effect of sporulation conditions on the resistance of Bacillus subtilis spores to heat and high pressure. Appl Microbiol Biotechnol 2011; 90:1409-17. [DOI: 10.1007/s00253-011-3183-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 02/14/2011] [Accepted: 02/14/2011] [Indexed: 10/18/2022]
|
46
|
Sun W, Romagnoli JA, Palazoglu A, Stroeve P. Characterization of Surface Coats of Bacterial Spores with Atomic Force Microscopy and Wavelets. Ind Eng Chem Res 2011. [DOI: 10.1021/ie101153y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wei Sun
- College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jose A. Romagnoli
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803-7303, United States
| | - Ahmet Palazoglu
- Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616, United States
| | - Pieter Stroeve
- Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616, United States
| |
Collapse
|
47
|
Seale RB, Bremer PJ, Flint SH, McQuillan AJ. Characterization of spore surfaces from a Geobacillus sp. isolate by pH dependence of surface charge and infrared spectra. J Appl Microbiol 2010; 109:1339-48. [PMID: 20522147 DOI: 10.1111/j.1365-2672.2010.04760.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS The surfaces of spores from a Geobacillus sp. isolated from a milk powder production line were examined to obtain fundamental information relevant to bacterial spore adhesion to materials. MATERIALS AND RESULTS The surfaces of spores were characterized using transmission electron microscopy and infrared spectroscopy. Thin sections of spores stained with ruthenium red revealed an exosporium with a hair-like nap around the spores. Attenuated total reflection infrared spectra of the spores exposed to different pH solutions on a ZnSe prism revealed that pH-sensitive carboxyl and phosphodiester groups associated with proteins and polysaccharides contributed to the spore's negative charge which was revealed by our previous zeta potential measurements on the spores. Lowering the pH to the isoelectric point of spores resulted in an increase in intensity of all spectral bands, indicating that the spores moved closer to the zinc selenide (ZnSe) surface as the charged surface groups were neutralized and the spore surface polymers compressed. The attachment of spores to stainless steel was threefold higher at pH 3 compared with pH 7. CONCLUSIONS This research showed that spore attachment to surfaces is influenced by electrostatic interactions, surface polymer conformation and associated steric interactions. SIGNIFICANCE AND IMPACT OF THE STUDY The adhesion of thermophilic spores is largely controlled by functional groups of surface polymers and polymer conformation.
Collapse
Affiliation(s)
- R B Seale
- Department of Food Science, University of Otago, Dunedin, New Zealand
| | | | | | | |
Collapse
|
48
|
Alsteens D, Dague E, Verbelen C, Andre G, Dupres V, Dufrêne YF. Nanoscale imaging of microbial pathogens using atomic force microscopy. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2010; 1:168-80. [PMID: 20049788 DOI: 10.1002/wnan.18] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The nanoscale exploration of microbes using atomic force microscopy (AFM) is an exciting research field that has expanded rapidly in the past years. Using AFM topographic imaging, investigators can visualize the surface structure of live cells under physiological conditions and with unprecedented resolution. In doing so, the effect of drugs and chemicals on the fine cell surface architecture can be monitored. Real-time imaging offers a means to follow dynamic events such as cell growth and division. In parallel, chemical force microscopy (CFM), in which AFM tips are modified with specific functional groups, allows researchers to measure interaction forces, such as hydrophobic forces, and to resolve nanoscale chemical heterogeneities on cells, on a scale of only approximately 25 functional groups. Lastly, molecular recognition imaging using spatially resolved force spectroscopy, dynamic recognition imaging or immunogold detection, enables microscopists to localize specific receptors, such as cell adhesion proteins or antibiotic binding sites. These noninvasive nanoscale analyses provide new avenues in pathogenesis research, particularly for investigating the action mode of antimicrobial drugs, and for elucidating the molecular basis of pathogen-host interactions.
Collapse
Affiliation(s)
- David Alsteens
- Unité de Chimie des Interfaces, Université Catholique de Louvain, Croix du Sud 2/18, B-1348 Louvain-la-Neuve, Belgium
| | | | | | | | | | | |
Collapse
|
49
|
Ferencko L, Rotman B. Constructing fluorogenic Bacillus spores (F-spores) via hydrophobic decoration of coat proteins. PLoS One 2010; 5:e9283. [PMID: 20174569 PMCID: PMC2824812 DOI: 10.1371/journal.pone.0009283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 01/29/2010] [Indexed: 11/24/2022] Open
Abstract
Background Bacterial spores are protected by a coat consisting of about 60 different proteins assembled as a biochemically complex structure with intriguing morphological and mechanical properties. Historically, the coat has been considered a static structure providing rigidity and mainly acting as a sieve to exclude exogenous large toxic molecules, such as lytic enzymes. Over recent years, however, new information about the coat's architecture and function have emerged from experiments using innovative tools such as automated scanning microscopy, and high resolution atomic force microscopy. Principal Findings Using thin-section electron microscopy, we found that the coat of Bacillus spores has topologically specific proteins forming a layer that is identifiable because it spontaneously becomes decorated with hydrophobic fluorogenic probes from the milieu. Moreover, spores with decorated coat proteins (termed F-spores) have the unexpected attribute of responding to external germination signals by generating intense fluorescence. Fluorescence data from diverse experimental designs, including F-spores constructed from five different Bacilli species, indicated that the fluorogenic ability of F-spores is under control of a putative germination-dependent mechanism. Conclusions This work uncovers a novel attribute of spore-coat proteins that we exploited to decorate a specific layer imparting germination-dependent fluorogenicity to F-spores. We expect that F-spores will provide a model system to gain new insights into structure/function dynamics of spore-coat proteins.
Collapse
Affiliation(s)
- Linda Ferencko
- BCR Diagnostics, Jamestown, Rhode Island, United States of America
| | - Boris Rotman
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, United States of America
- BCR Diagnostics, Jamestown, Rhode Island, United States of America
- * E-mail:
| |
Collapse
|
50
|
Mato Rodriguez L, Alatossava T. Effects of copper on germination, growth and sporulation of Clostridium tyrobutyricum. Food Microbiol 2010; 27:434-7. [PMID: 20227610 DOI: 10.1016/j.fm.2010.01.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 01/12/2010] [Accepted: 01/17/2010] [Indexed: 01/11/2023]
Abstract
The effects of copper (Cu(2+)) on spore germination, vegetative growth and sporulation of Clostridium tyrobutyricum, which is capable to causing texture and flavour defects in Emmental cheese, were studied. Spore suspensions of three different strains were used as starting material for two experimental set-ups. The first studied the effects of supplemented (0-30 ppm) copper in RCM medium during spore germination and vegetative growth of C. tyrobutyricum measured by plating. The second set-up studied the effects of copper (0-30 ppm) in RCM medium during growth and sporulation of C. tyrobutyricum as measured by optical density at 550 nm and by platings after heat treatment of the samples respectively. Inhibition of germination, vegetative growth and sporulation processes by copper was strain-dependent. Both sporulation and germination were more sensitive than vegetative growth of C. tyrobutyricum to the inhibitory effects of copper. Copper, at the concentrations investigated in this study, inhibits spore germination of C. tyrobutyricum strains. Consequently copper may reduce the risk of late blowing spoilage from in the germination of C. tyrobutyricum spores during the ripening period of Emmental cheese.
Collapse
Affiliation(s)
- L Mato Rodriguez
- Department of Food and Environmental Sciences/Division of Food Technology, Viikki campus, University of Helsinki, Helsinki, Finland
| | | |
Collapse
|