HEAT‐ACTIVATION OF BACTERIAL SPORES<sup>a,</sup><sup>b,</sup>

Desrosier, N. W.; Heiligman, F.

doi:10.1111/j.1365-2621.1956.tb16892.x

Cited by 20 publications

(10 citation statements)

References 15 publications

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“…All colonies from spore-specific cultivation plates were isolated, whereas only a representative selection was isolated from total cultivation plates. In addition, the germination efficiencies could be different for bacterial spores that were activated by heat shocking prior to cultivation and those that were not (16,37).…”

Section: Discussionmentioning

confidence: 99%

Characterization of Airborne Bacteria at an Underground Subway Station

Dybwad

Granum

Bruheim

et al. 2012

Appl Environ Microbiol

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The reliable detection of airborne biological threat agents depends on several factors, including the performance criteria of the detector and its operational environment. One step in improving the detector's performance is to increase our knowledge of the biological aerosol background in potential operational environments. Subway stations are enclosed public environments, which may be regarded as potential targets for incidents involving biological threat agents. In this study, the airborne bacterial community at a subway station in Norway was characterized (concentration level, diversity, and virulence-and survival-associated properties). In addition, a SASS 3100 high-volume air sampler and a matrix-assisted laser desorption ionization-time of flight mass spectrometry-based isolate screening procedure was used for these studies. The daytime level of airborne bacteria at the station was higher than the nighttime and outdoor levels, and the relative bacterial spore number was higher in outdoor air than at the station. The bacterial content, particle concentration, and size distribution were stable within each environment throughout the study (May to September 2010). The majority of the airborne bacteria belonged to the genera Bacillus, Micrococcus, and Staphylococcus, but a total of 37 different genera were identified in the air. These results suggest that anthropogenic sources are major contributors to airborne bacteria at subway stations and that such airborne communities could harbor virulence-and survival-associated properties of potential relevance for biological detection and surveillance, as well as for public health. Our findings also contribute to the development of realistic testing and evaluation schemes for biological detection/surveillance systems by providing information that can be used to mimic real-life operational airborne environments in controlled aerosol test chambers.

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Section: Discussionmentioning

confidence: 99%

Characterization of Airborne Bacteria at an Underground Subway Station

Dybwad

Granum

Bruheim

et al. 2012

Appl Environ Microbiol

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“…Changes in light diffraction during spore germination (optical density at 580 nm [OD 580 ]) were monitored using a Tecan Infinite M200 96-well plate reader set at 580 nm (Tecan Group, Männedorf, Switzerland). C. difficile spores were heat activated at 65°C for 30 min (13). After heat activation, spores were cooled to room temperature and resuspended in germination buffer (100 mM sodium phosphate buffer, pH 6.0, 0.5% NaHCO 3 ) to an OD 580 of 1.…”

Section: Methodsmentioning

confidence: 99%

Kinetic Evidence for the Presence of Putative Germination Receptors in C lostridium difficile Spores

2010

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Clostridium difficile is a spore-forming bacterium that causes Clostridium difficile-associated disease (CDAD). Intestinal microflora keeps C. difficile in the spore state and prevents colonization. Following antimicrobial treatment, the microflora is disrupted, and C. difficile spores germinate in the intestines. The resulting vegetative cells are believed to fill empty niches left by the depleted microbial community and establish infection. Thus, germination of C. difficile spores is the first required step in CDAD. Interestingly, C. difficile genes encode most known spore-specific protein necessary for germination, except for germination (Ger) receptors. Even though C. difficile Ger receptors have not been identified, taurocholate (a bile salt) and glycine (an amino acid) have been shown to be required for spore germination. Furthermore, chenodeoxycholate, another bile salt, can inhibit taurocholate-induced C. difficile spore germination. In the present study, we examined C. difficile spore germination kinetics to determine whether taurocholate acts as a specific germinant that activates unknown germination receptors or acts nonspecifically by disrupting spores' membranes. Kinetic analysis of C. difficile spore germination suggested the presence of distinct receptors for taurocholate and glycine. Furthermore, taurocholate, glycine, and chenodeoxycholate seem to bind to C. difficile spores through a complex mechanism, where both receptor homo-and heterocomplexes are formed. The kinetic data also point to an ordered sequential progression of binding where taurocholate must be recognized first before detection of glycine can take place. Finally, comparing calculated kinetic parameters with intestinal concentrations of the two germinants suggests a mechanism for the preferential germination of C. difficile spores in antibiotic-treated individuals.

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“…Changes in light diffraction during spore germination were monitored at an optical density of 580 nm (OD 580 ) on a Biomate 5 spectrophotometer (ThermoElectron Corporation, Waltham, MA). C. sordellii spores were heat activated at 70°C for 30 min (17). After heat activation, spores were cooled to room temperature and resuspended in germination buffer (100 mM sodium phosphate buffer, pH 6.0) to an OD 580 of 1, as done previously (2).…”

Section: Methodsmentioning

confidence: 99%

Requirements for Germination ofClostridium sordelliiSporesIn Vitro

Ramírez

Abel-Santos

2010

J Bacteriol

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Clostridium sordellii is a spore-forming, obligately anaerobic, Gram-positive bacterium that can cause toxic shock syndrome after gynecological procedures. Although the incidence of C. sordellii infection is low, it is fatal in most cases. Since spore germination is believed to be the first step in the establishment of Bacilli and Clostridia infections, we analyzed the requirements for C. sordellii spore germination in vitro. Our data showed that C. sordellii spores require three structurally different amino acids and bicarbonate for maximum germination. Unlike the case for Bacilli species, D-alanine had no effect on C. sordellii spore germination. C. sordellii spores germinated only in a narrow pH range between 5.7 and 6.5. In contrast, C. sordellii spore germination was significantly less sensitive to temperature changes than that of the Bacilli. The analysis of the kinetics of C. sordellii spore germination showed strong allosteric behavior in the binding of L-phenylalanine and L-alanine but not in that of bicarbonate or L-arginine. By comparing germinant apparent binding affinities to their known in vivo concentrations, we postulated a mechanism for differential C. sordellii spore activation in the female reproductive tract.

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HEAT‐ACTIVATION OF BACTERIAL SPORES^a,^b,

Cited by 20 publications

References 15 publications

Characterization of Airborne Bacteria at an Underground Subway Station

Characterization of Airborne Bacteria at an Underground Subway Station

Kinetic Evidence for the Presence of Putative Germination Receptors in C lostridium difficile Spores

Requirements for Germination ofClostridium sordelliiSporesIn Vitro

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HEAT‐ACTIVATION OF BACTERIAL SPORESa,b,

Cited by 20 publications

References 15 publications

Characterization of Airborne Bacteria at an Underground Subway Station

Characterization of Airborne Bacteria at an Underground Subway Station

Kinetic Evidence for the Presence of Putative Germination Receptors in C lostridium difficile Spores

Requirements for Germination ofClostridium sordelliiSporesIn Vitro

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HEAT‐ACTIVATION OF BACTERIAL SPORES^a,^b,