Monitoring the Kinetics of <i>Bacillus subtilis</i> Endospore Germination via Surface-Enhanced Raman Scattering Spectroscopy

Daniels, Jacquitta K.; Caldwell, Thomas P.; Christensen, Kenneth A.; Chumanov, George

doi:10.1021/ac052009v

Cited by 51 publications

(52 citation statements)

References 30 publications

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“…3A shows the particle size distributions measured over a 1-min time period initiated 5 min after the nebulization began. The peaks of these distributions occurred at approximately the same particle size, D p = 0.71 µm, representative of intact endospores [existing literature refers to the aerodynamic diameters of the tested Bacillus spores ranging from 0.7 to 0.9 µm (Li et al, 1999;Aizenberg et al, 2000) and microscopic optical diameter of ~1 µm for non-germinated endospores (Daniels et al, 2006)]. These data suggest that the tested dry dilution flows were sufficient to shrink the nebulizer-generated particles to the spore size as water content evaporated between the aerosolization point (nebulizer) and the chamber's entry point.…”

Section: Characterization Of the Challenge Aerosol And Particle Lossementioning

confidence: 99%

Method for Studying Survival of Airborne Viable Microorganisms in Combustion Environments: Development and Evaluation

Grinshpun

Adhikari

et al. 2010

Aerosol Air Qual. Res.

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Inactivation of airborne microorganisms due to thermal or chemical air treatment has gained considerable attention. Destruction of aerosolized biothreat agents in environments containing combustion products is particularly relevant to military and counterterrorism situations because some pathogens may survive an explosion or fire in a bio-weapon facility and be dispersed in the atmosphere. Energetic materials with biocidal properties are being sought to effectively inactivate stress-resistant aerosolized microorganisms. Consequently, appropriate methods are needed to test these materials. We designed and built a state-of-the-art experimental facility and developed protocols for assessing the survival of aerosolized microorganisms exposed to combustion. The facility uses a continuous-flow design and includes an aerosolization unit, a test (combustion) chamber, and a measurement system for bioaerosol particles exposed to combustion environments for sub-second time intervals. The experimental method was tested with Bacillus endospores. We assessed the inactivation of aerosolized spores exposed to a gaseous hydrocarbon flame and to combustion of aluminum-based energetic composites (including a novel iodine-containing filled nanocomposite material). Two combustion configurations were evaluated -a vertical strand containing a consolidated material and a specially designed burner in which a fuel powder is fed into a gaseous hydrocarbon flame. It was established that the bioaerosol inactivation may be overestimated due to exposure of spores on collection filters to the combustion products throughout the test. The overestimation can be mitigated by reducing the collection time and minimizing the formation of soot. The experimental facility and method developed in this study enables evaluating effects caused by biocidal products during combustion. The present version of the set-up provides the capability of detecting inactivation levels of ~2.2 × 10 5 (over five-log viability reduction) its further design modifications can potentially enable measuring bioaerosol inactivation as high as ~10 7 . The method was utilized for establishing feasibility of the new iodine-containing material for microbial agent defeat applications.

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Section: Characterization Of the Challenge Aerosol And Particle Lossementioning

confidence: 99%

Method for Studying Survival of Airborne Viable Microorganisms in Combustion Environments: Development and Evaluation

Grinshpun

Adhikari

et al. 2010

Aerosol Air Qual. Res.

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“…Thus, they provide the unique advantage of differentiating taxonomic entities at the species or subspecies level on the basis of variations in the spectral features of bacterial cells (41). Since the two groundbreaking publications in Nature about the use of infrared spectroscopy (57) and Raman spectroscopy (61) to study microorganisms, these two techniques have been extensively employed to detect and discriminate different microorganisms and have been shown to be useful as real-time typing methods in bacterial epidemiology (3,7,33,34,36,37,48,49,59,60,65,77). Fourier-transformed infrared (FT-IR) spectroscopy, in combination with multivariate analyses, has been used to identify and discriminate C. jejuni and C. coli (54,55).…”

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confidence: 99%

Comprehensive Detection and Discrimination of Campylobacter Species by Use of Confocal Micro-Raman Spectroscopy and Multilocus Sequence Typing

Huang

Miller

et al. 2012

J Clin Microbiol

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A novel strategy for the rapid detection and identification of traditional and emerging Campylobacter strains based upon Raman spectroscopy (532 nm) is presented here. A total of 200 reference strains and clinical isolates of 11 different Campylobacter species recovered from infected animals and humans from China and North America were used to establish a global Raman spectroscopy-based dendrogram model for Campylobacter identification to the species level and cross validated for its feasibility to predict Campylobacter -associated food-borne outbreaks. Bayesian probability coupled with Monte Carlo estimation was employed to validate the established Raman classification model on the basis of the selected principal components, mainly protein secondary structures, on the Campylobacter cell membrane. This Raman spectroscopy-based typing technique correlates well with multilocus sequence typing and has an average recognition rate of 97.21%. Discriminatory power for the Raman classification model had a Simpson index of diversity of 0.968. Intra- and interlaboratory reproducibility with different instrumentation yielded differentiation index values of 4.79 to 6.03 for wave numbers between 1,800 and 650 cm −1 and demonstrated the feasibility of using this spectroscopic method at different laboratories. Our Raman spectroscopy-based partial least-squares regression model could precisely discriminate and quantify the actual concentration of a specific Campylobacter strain in a bacterial mixture (regression coefficient, >0.98; residual prediction deviation, >7.88). A standard protocol for sample preparation, spectral collection, model validation, and data analyses was established for the Raman spectroscopic technique. Raman spectroscopy may have advantages over traditional genotyping methods for bacterial epidemiology, such as detection speed and accuracy of identification to the species level.

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“…First, it was verified whether the particles aerosolized by the nebulizer and dried by the endospores [existing literature refers to the aerodynamic diameters of these spores ranging from 0.7 to 0.9 µm (Li et al, 1999;Aizenberg et al, 2000) and microscopic optical diameter of ~1 µm for non-germinated endospores (Daniels et al, 2006)]. These data suggest that the tested dry dilution flows were sufficient to shrink the nebulizer-generated particles to the spore size as water content evaporated between the aerosolization point (nebulizer) and the chamber's entry point.…”

Section: Characterization Of the Challenge Aerosol And Particle Lossementioning

confidence: 99%

Inactivation of Aerosolized Biological Agents using Filled Nanocomposite Materials

Grinshpun¹,

Schoenitz²,

Dreizin³

et al. 2013

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)2. REPORT TYPE 3. DATES COVERED (From -To) Approved for public release; distribution is unlimited.In this multi-institutional grant, a new method for inactivating aerosolized biological agents was developed utilizing a new class of energetic materials: filled nanocomposite materials. The implemented approach enabled a controllable release of iodine-based oxidizing species in the combustion environment to inactivate viable airborne bio-agents, such as stress-resistant bacterial spores and viruses. Composites with adjustable Al/I2 ratios were produced. A state-of-the-art experimental facility was developed for studying how novel energetic formulations and their combustion products affect the viability of aerosolized spores and viruses during a short (< 1 s) exposure times. Controlled bioaerosol dispersal and sample collection protocols were developed and optimized. The dry-heat inactivation of aerosolized spores was quantified separately from chemical effects and linked to DNA repair mechanisms. It was concluded that the iodine-containing powder provided significantly more effective inactivation of airborne spores than non-iodinated powders. The results of this research help to better understand physical, physicochemical, and biological properties associated with inactivation of aerosolized bio-agents in combustion environments.Bioaerosol inactivation, spore, virus, bio-agent defeat, energetic material, iodine 1.000 000 x E -10 1.013 25 x E +2 1.000 000 x E +2 1.000 000 x E -28 1.054 350 x E +3 4.184 000 4.184 000 x E -2 3.700 000 x E +1 1.745 329 x E -2 t k = (t o f + 459.67)/1.8 1.602 19 x E -19 1.000 000 x E -7 1.000 000 x E -7 3.048 000 x E -1 1.355 818 3.785 412 x E -3 2.540 000 x E -2 1.000 000 x E +9 1.000 000 4.183 4.448 222 x E +3 6.894 757 x E +3 1.000 000 x E +2 1.000 000 x E -6 2.540 000 x E -5 1.609 344 x E +3 2.834 952 x E -2 4.448 222 1.129 848 x E -1 1.751 268 x E +2 4.788 026 x E -2 6.894 757 4.535 924 x E -1 4.214 011 x E -2 1.601 846 x E +1 1.000 000 x E -2 2.579 760 x E -4 1.000 000 x E -8 1.459 390 x E +1 1. ABSTRACTIn this multi-institutional grant, a new method for ...

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Monitoring the Kinetics of Bacillus subtilis Endospore Germination via Surface-Enhanced Raman Scattering Spectroscopy

Cited by 51 publications

References 30 publications

Method for Studying Survival of Airborne Viable Microorganisms in Combustion Environments: Development and Evaluation

Method for Studying Survival of Airborne Viable Microorganisms in Combustion Environments: Development and Evaluation

Comprehensive Detection and Discrimination of Campylobacter Species by Use of Confocal Micro-Raman Spectroscopy and Multilocus Sequence Typing

Inactivation of Aerosolized Biological Agents using Filled Nanocomposite Materials

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