scholarly journals Survival and ice nucleation activity of bacteria as aerosols in a cloud simulation chamber

2015 ◽  
Vol 15 (11) ◽  
pp. 6455-6465 ◽  
Author(s):  
P. Amato ◽  
M. Joly ◽  
C. Schaupp ◽  
E. Attard ◽  
O. Möhler ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Numerical Models ◽  
Survival Rates ◽  
Total Duration ◽  
Life Time ◽  
Ice Nucleation ◽  
Cloud Formation ◽  
Bacterial Cells ◽  
Lack Of Information ◽  
Simulation Chamber

Abstract. The residence time of bacterial cells in the atmosphere is predictable by numerical models. However, estimations of their aerial dispersion as living entities are limited by a lack of information concerning survival rates and behavior in relation to atmospheric water. Here we investigate the viability and ice nucleation (IN) activity of typical atmospheric ice nucleation active bacteria (Pseudomonas syringae and P. fluorescens) when airborne in a cloud simulation chamber (AIDA, Karlsruhe, Germany). Cell suspensions were sprayed into the chamber and aerosol samples were collected by impingement at designated times over a total duration of up to 18 h, and at some occasions after dissipation of a cloud formed by depressurization. Aerosol concentration was monitored simultaneously by online instruments. The cultivability of airborne cells decreased exponentially over time with a half-life time of 250 ± 30 min (about 3.5 to 4.5 h). In contrast, IN activity remained unchanged for several hours after aerosolization, demonstrating that IN activity was maintained after cell death. Interestingly, the relative abundance of IN active cells still airborne in the chamber was strongly decreased after cloud formation and dissipation. This illustrates the preferential precipitation of IN active cells by wet processes. Our results indicate that from 106 cells aerosolized from a surface, one would survive the average duration of its atmospheric journey estimated at 3.4 days. Statistically, this corresponds to the emission of 1 cell that achieves dissemination every ~ 33 min m−2 of cultivated crops fields, a strong source of airborne bacteria. Based on the observed survival rates, depending on wind speed, the trajectory endpoint could be situated several hundreds to thousands of kilometers from the emission source. These results should improve the representation of the aerial dissemination of bacteria in numeric models.

scholarly journals Survival and ice nucleation activity of bacteria as aerosols in a cloud simulation chamber

2015 ◽  
Vol 15 (3) ◽  
pp. 4055-4082 ◽  
Author(s):  
P. Amato ◽  
M. Joly ◽  
C. Schaupp ◽  
E. Attard ◽  
O. Möhler ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Numerical Models ◽  
Survival Rates ◽  
Total Duration ◽  
Life Time ◽  
Ice Nucleation ◽  
Cloud Formation ◽  
Bacterial Cells ◽  
Strong Source ◽  
Simulation Chamber

Abstract. The residence time of bacterial cells in the atmosphere is predictable by numerical models. However, estimations of their aerial dispersion as living entities are limited by lacks of information concerning survival rates and behavior in relation to atmospheric water. Here we investigate the viability and ice nucleation (IN) activity of typical atmospheric ice nucleation active bacteria (Pseudomonas syringae and P. fluorescens) when airborne in a cloud simulation chamber (AIDA, Karlsruhe, Germany). Cell suspensions were sprayed into the chamber and aerosol samples were collected by impingement at designated times over a total duration of up to 18 h, and at some occasions after dissipation of a cloud formed by depressurization. Aerosol concentration was monitored simultaneously by online instruments. The cultivability of airborne cells decreased exponentially over time with a half-life time of 250 ± 30 min (about 3.5 to 4.5 h). In contrast, IN activity remained unchanged for several hours after aerosolization, demonstrating that IN activity was maintained after cell death. Interestingly, the relative abundance of IN active cells still airborne in the chamber was strongly decreased after cloud formation and dissipation. This illustrates the preferential precipitation of IN active cells by wet processes. Our results indicate that from 106 = cells aerosolized from a surface, one would survive the average duration of its atmospheric journey estimated at 3.4 days. Statistically, this corresponds to the emission of 1 cell that achieves dissemination every ~33 min per m2 of cultivated crops fields, a strong source of airborne bacteria. Based on the observed survival rates, depending on wind speed, the trajectory endpoint could be situated several hundreds to thousands of kilometers from the emission source. These results should improve the representation of the aerial dissemination of bacteria in numeric models.

scholarly journals Effects of atmospheric conditions on ice nucleation activity of <i>Pseudomonas</i>

2012 ◽  
Vol 12 (22) ◽  
pp. 10667-10677 ◽  
Author(s):  
E. Attard ◽  
H. Yang ◽  
A.-M. Delort ◽  
P. Amato ◽  
U. Pöschl ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Acidic Ph ◽  
Bacterial Cells ◽  
Atmospheric Conditions ◽  
Ice Nucleation Protein ◽  
Ice Melt ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Although ice nuclei from bacterial origin are known to be efficient at the highest temperatures known for ice catalysts, quantitative data are still needed to assess their role in cloud processes. Here we studied the effects of three typical cloud conditions (i) acidic pH (ii) NO2 and O3 exposure and (iii) UV-A exposure on the ice nucleation activity (INA) of four Pseudomonas strains. Three of the Pseudomonas syringae strains were isolated from cloud water and the phyllosphere and Pseudomonas fluorescens strain CGina-01 was isolated from Antarctic glacier ice melt. Among the three conditions tested, acidic pH caused the most significant effects on INA likely due to denaturation of the ice nucleation protein complex. Exposure to NO2 and O3 gases had no significant or only weak effects on the INA of two P. syringae strains whereas the INA of P. fluorescens CGina-01 was significantly affected. The INA of the third P. syringae strain showed variable responses to NO2 and O3 exposure. These differences in the INA of different Pseudomonas suggest that the response to atmospheric conditions could be strain-specific. After UV-A exposure, a substantial loss of viability of all four strains was observed whereas their INA decreased only slightly. This corroborates the notion that under certain conditions dead bacterial cells can maintain their INA. Overall, the negative effects of the three environmental factors on INA were more significant at the warmer temperatures. Our results suggest that in clouds where temperatures are near 0 °C, the importance of bacterial ice nucleation in precipitation processes could be reduced by some environmental factors.

scholarly journals High-resolution ice nucleation spectra of sea-ice bacteria: implications for cloud formation and life in frozen environments

2008 ◽  
Vol 5 (3) ◽  
pp. 865-873 ◽  
Author(s):  
K. Junge ◽  
B. D. Swanson
Keyword(s):  
High Resolution ◽  
Sea Ice ◽  
Freezing Point ◽  
Free Fall ◽  
Ice Nucleation ◽  
Survival Strategies ◽  
Cloud Formation ◽  
Ice Formation ◽  
Bacterial Cells ◽  
Antarctic Sea Ice

Abstract. Even though studies of Arctic ice forming particles suggest that a bacterial or viral source derived from open leads could be important for ice formation in Arctic clouds (Bigg and Leck, 2001), the ice nucleation potential of most polar marine psychrophiles or viruses has not been examined under conditions more closely resembling those in the atmosphere. In this paper, we examined the ice nucleation activity (INA) of several representative Arctic and Antarctic sea-ice bacterial isolates and a polar Colwellia phage virus. High-resolution ice nucleation spectra were obtained for droplets containing bacterial cells or virus particles using a free-fall freezing tube technique. The fraction of frozen droplets at a particular droplet temperature was determined by measuring the depolarized light scattering intensity from solution droplets in free-fall. Our experiments revealed that all sea-ice isolates and the virus nucleated ice at temperatures very close to the homogeneous nucleation temperature for the nucleation medium – which for artificial seawater was –42.2±0.3°C. Our results suggest that immersion freezing of these marine psychro-active bacteria and viruses would not be important for heterogeneous ice nucleation processes in polar clouds or to the formation of sea ice. These results also suggested that avoidance of ice formation in close proximity to cell surfaces might be one of the cold-adaptation and survival strategies for sea-ice bacteria. The fact that INA occurs at such low temperature could constitute one factor that explains the persistence of metabolic activities at temperatures far below the freezing point of seawater.

scholarly journals Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions

2008 ◽  
Vol 5 (2) ◽  
pp. 1445-1468 ◽  
Author(s):  
O. Möhler ◽  
D. G. Georgakopoulos ◽  
C. E. Morris ◽  
S. Benz ◽  
V. Ebert ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Cloud Condensation Nuclei ◽  
Bacterial Species ◽  
Ice Nucleation ◽  
Cloud Chamber ◽  
Bacterial Cells ◽  
Spray Formation ◽  
Temperature Range ◽  
Expansion Cooling ◽  
Activation Conditions

Abstract. The ice nucleation activities of five different Pseudomonas syringae, Pseudomonas viridiflava and Erwinia herbicola bacterial species and of SnomaxTM were investigated in the temperature range between −5 and −15°C. Water suspensions of these bacteria were directly spray into the cloud chamber of the AIDA facility of Forschungszentrum Karlsruhe at a temperature of −5.7°. At this temperature, about 1% of the SnomaxTM cells induced freezing of the spray droplets before they evaporated in the cloud chamber. The other suspensions of living cells didn't induce any measurable ice concentration during spray formation at −5.7°. The remaining aerosol was exposed to typical cloud activation conditions in subsequent experiments with expansion cooling to about −11°C. During these experiments, the bacterial cells first acted as cloud condensation nuclei to form cloud droplets and then eventually acted as ice nuclei to freeze the droplets. The results indicate that the bacteria investigated in the present study are mainly ice active in the temperature range between −7 and −11°C with an INA fraction of the order of 10−4. The ice nucleation efficiency of SnomaxTM cells was much larger with an INA fraction of 0.2 at temperatures around −8°C.

scholarly journals Effects of atmospheric conditions on ice nucleation activity of <i>Pseudomonas</i>

2012 ◽  
Vol 12 (4) ◽  
pp. 9491-9516 ◽  
Author(s):  
E. Attard ◽  
H. Yang ◽  
A.-M. Delort ◽  
P. Amato ◽  
U. Pöschl ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Acidic Ph ◽  
Bacterial Cells ◽  
Atmospheric Conditions ◽  
Ice Nucleation Protein ◽  
Ice Melt ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Although ice nuclei from bacterial origin are known to be efficient at the highest temperatures known for ice catalysts, quantitative data are still needed to assess their role in cloud processes. Here we studied the effects of three typical cloud conditions (i) acidic pH (ii) NO2 and O3 exposure and (iii) UV-A exposure on the ice nucleation activity (INA) of four Pseudomonas strains. Three of the Pseudomonas syringae strains were isolated from cloud water and the phyllosphere and Pseudomonas fluorescens strain CGina-01 was isolated from Antarctic glacier ice melt. Among the three conditions tested, acidic pH caused the most significant effects on INA likely due to denaturation of the ice nucleation protein complex. Exposure to NO2 and O3 gases had no significant or only weak effects on the INA of two P. syringae strains whereas the INA of P. fluorescens CGina-01 was significantly affected. The INA of the third P. syringae strain showed variable responses to NO2 and O3 exposure. These differences in the INA of different Pseudomonas suggest that the response to atmospheric conditions could be strain-specific. After UV-A exposure, a substantial loss of viability of all four strains was observed whereas their INA decreased only slightly. This corroborates the notion that under certain conditions dead bacterial cells can maintain their INA. Overall, the negative effects of the three environmental factors on INA were more significant at the warmer temperatures. Our results suggest that in clouds where temperatures are near 0 °C, the importance of bacterial ice nucleation in precipitation processes could be reduced by some environmental factors.

scholarly journals High-resolution ice nucleation spectra of sea-ice bacteria: implications for cloud formation and life in frozen environments

2007 ◽  
Vol 4 (6) ◽  
pp. 4261-4282 ◽  
Author(s):  
K. Junge ◽  
B. D. Swanson
Keyword(s):  
High Resolution ◽  
Sea Ice ◽  
Freezing Point ◽  
Free Fall ◽  
Ice Nucleation ◽  
Survival Strategies ◽  
Cloud Formation ◽  
The Arctic ◽  
Bacterial Cells ◽  
Antarctic Sea Ice

Abstract. Even though studies of Arctic ice forming particles suggest that a bacterial or viral source derived from open leads could be important for cloud formation in the Arctic (Bigg and Leck, 2001), the ice nucleation potential of most polar marine psychrophiles or viruses has not been examined under conditions more closely resembling those in the atmosphere. In this paper, we examined the ice nucleation activity (INA) of several representative Arctic and Antarctic sea-ice bacterial isolates and a polar Colwellia phage virus. High-resolution ice nucleation spectra were obtained for droplets containing bacterial cells or virus particles using a free-fall freezing tube technique. The fraction of frozen droplets at a particular droplet temperature was determined by measuring the depolarized light scattering intensity from solution droplets in free-fall. Our experiments revealed that all sea-ice isolates and the virus nucleated ice at temperatures very close to the homogeneous nucleation temperature for the nucleation medium – which for artificial seawater was −42.2±0.3°C. Our results indicated that these marine psychro-active bacteria and viruses are not important for heterogeneous ice nucleation processes in sea ice or polar clouds. These results also suggested that avoidance of ice formation in close proximity to cell surfaces might be one of the cold-adaptation and survival strategies for sea-ice bacteria. The fact that INA occurs at such low temperature could constitute one factor that explains the persistence of metabolic activities at temperatures far below the freezing point of seawater.

scholarly journals Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions

2008 ◽  
Vol 5 (5) ◽  
pp. 1425-1435 ◽  
Author(s):  
O. Möhler ◽  
D. G. Georgakopoulos ◽  
C. E. Morris ◽  
S. Benz ◽  
V. Ebert ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Cloud Condensation Nuclei ◽  
Bacterial Species ◽  
Ice Nucleation ◽  
Cloud Chamber ◽  
Bacterial Cells ◽  
Active Fraction ◽  
Temperature Range ◽  
Spray Droplets ◽  
Immersion Freezing

Abstract. The ice nucleation activities of five different Pseudomonas syringae, Pseudomonas viridiflava and Erwinia herbicola bacterial species and of Snomax™ were investigated in the temperature range between −5 and −15°C. Water suspensions of these bacteria were directly sprayed into the cloud chamber of the AIDA facility of Forschungszentrum Karlsruhe at a temperature of −5.7°C. At this temperature, about 1% of the Snomax™ cells induced immersion freezing of the spray droplets before the droplets evaporated in the cloud chamber. The living cells didn't induce any detectable immersion freezing in the spray droplets at −5.7°C. After evaporation of the spray droplets the bacterial cells remained as aerosol particles in the cloud chamber and were exposed to typical cloud formation conditions in experiments with expansion cooling to about −11°C. During these experiments, the bacterial cells first acted as cloud condensation nuclei to form cloud droplets. Then, only a minor fraction of the cells acted as heterogeneous ice nuclei either in the condensation or the immersion mode. The results indicate that the bacteria investigated in the present study are mainly ice active in the temperature range between −7 and −11°C with an ice nucleation (IN) active fraction of the order of 10−4. In agreement to previous literature results, the ice nucleation efficiency of Snomax™ cells was much larger with an IN active fraction of 0.2 at temperatures around −8°C.

scholarly journals Microbiology and atmospheric processes: the role of biological particles in cloud physics

2007 ◽  
Vol 4 (6) ◽  
pp. 1059-1071 ◽  
Author(s):  
O. Möhler ◽  
P. J. DeMott ◽  
G. Vali ◽  
Z. Levin
Keyword(s):  
Cloud Condensation Nuclei ◽  
Diffusion Chamber ◽  
Ice Nucleation ◽  
Cloud Formation ◽  
Bacterial Cells ◽  
Biological Particles ◽  
Ice Nuclei ◽  
Potential Impact ◽  
The Impact

Abstract. As part of a series of papers on the sources, distribution and potential impact of biological particles in the atmosphere, this paper introduces and summarizes the potential role of biological particles in atmospheric clouds. Biological particles like bacteria or pollen may be active as both cloud condensation nuclei (CCN) and heterogeneous ice nuclei (IN) and thereby can contribute to the initial cloud formation stages and the development of precipitation through giant CCN and IN processes. The paper gives an introduction to aerosol-cloud processes involving CCN and IN in general and provides a short summary of previous laboratory, field and modelling work which investigated the CCN and IN activity of bacterial cells and pollen. Recent measurements of atmospheric ice nuclei with a continuous flow diffusion chamber (CFDC) and of the heterogeneous ice nucleation efficiency of bacterial cells are also briefly discussed. As a main result of this overview paper we conclude that a proper assessment of the impact of biological particles on tropospheric clouds needs new laboratory, field and modelling work on the abundance of biological particles in the atmosphere and their CCN and heterogeneous IN properties.

scholarly journals Freezing from the inside. Ice nucleation in <i>Escherichia coli</i> and <i>Escherichia coli</i> ghosts by inner membrane bound ice nucleation protein InaZ

2019 ◽  
Author(s):  
Johannes Kassmannhuber ◽  
Sergio Mauri ◽  
Mascha Rauscher ◽  
Nadja Brait ◽  
Lea Schöner ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Pseudomonas Syringae ◽  
Survival Rates ◽  
Ice Nucleation ◽  
Free Access ◽  
Ice Nucleation Protein ◽  
Inner Membrane ◽  
E Coli ◽  
Subzero Temperatures

Abstract. An N-terminal truncated form of the ice nucleation protein (INP) of Pseudomonas syringae lacking the transport sequence for the localization of InaZ in the outer membrane was fused to N- and C- terminal inner membrane (IM) anchors and expressed in Escherichia coli C41. The ice nucleation (IN) activity of the corresponding living recombinant E. coli catalyzing heterogeneous ice formation of super-cooled water at high subzero temperatures was tested by droplet freezing assay. Median freezing temperature (T50) of the parental living E. coli C41 cells without INP was detected at −20.1 °C and with inner membrane anchored INPs at T50 value between −7 °C and −9 °C demonstrating that IM anchored INPs facing the luminal IM site are able to induce IN from the inside of the bacterium almost similar to bacterial INPs located at the outer membrane. Bacterial Ghosts (BGs) derived from the different constructs showed first droplet freezing values between −6 °C and −8 °C whereas C41 BGs alone without carrying IM anchored INPs exhibit a T50 of −18.9 °C. The more efficient IN of INP-BGs compared to their living parental strains can be explained by the free access of IM anchored INP constructs to ultrapure water filling the inner space of the BGs. The cell killing rate of -NINP carrying E. coli at subzero temperatures is higher when compared to survival rates of the parental C41 strain.

scholarly journals Microbiology and atmospheric processes: the role of biological particles in cloud physics

2007 ◽  
Vol 4 (4) ◽  
pp. 2559-2591 ◽  
Author(s):  
O. Möhler ◽  
P. J. DeMott ◽  
G. Vali ◽  
Z. Levin
Keyword(s):  
Cloud Condensation Nuclei ◽  
Diffusion Chamber ◽  
Ice Nucleation ◽  
Cloud Formation ◽  
Bacterial Cells ◽  
Biological Particles ◽  
Ice Nuclei ◽  
Potential Impact ◽  
The Impact

Abstract. As part of a series of papers on the sources, distribution and potential impact of biological particles in the atmosphere, this paper introduces and summarizes the potential role of biological particles in atmospheric clouds. Biological particles like bacteria or pollen may be active as both cloud condensation nuclei (CCN) and heterogeneous ice nuclei (IN) and thereby can contribute to the initial cloud formation stages and the development of precipitation through giant CCN and IN processes. The paper gives an introduction to aerosol-cloud processes like CCN and IN in general and provides a short summary of previous laboratory, field and modelling work investigating the CCN and IN activity of bacterial cells and pollen. Recent measurements of atmospheric ice nuclei with a continuous flow diffusion chamber (CFDC) and of the heterogeneous ice nucleation efficiency of bacterial cells are also briefly discussed. As a main result of this overview paper we conclude that a proper assessment of the impact of biological particles on tropospheric clouds needs new laboratory, field and modelling work investigating the abundance of biological particles in the atmosphere and their CCN and heterogeneous IN properties.

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