Ice nucleation activity identified in some phytopathogenic Fusarium species

In order to know which species of Fusarium are ice nucleating and to determine the factors affecting their pathogenicity, ice nucleation activity (INA) was examined in Fusarium oxysporum, F. sporotrichioides, and F. tricinctum. Positive controls (lna+) used were F. acuminatum and F. avenaceum. The test for fungal INA was done with a simple and rapid tube nucleation assay. Twelve out of the 42 F. oxysporum isolates, and 8 out of 14 F. tricinctum isolates were lna+. No INA was detected in F sporotrichioides. In this test the threshold freezing temperature tended to increase with culture age, reaching a peak of -1°C in a few samples, which is as high as the warmest INA reported for bacteria, and higher than the INA detected in pure cultures of free-living fungi, lichen fungi, lichen algae and cyanobacteria. This is the first report of INA for F oxysporum.

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Macromolecular fungal ice nuclei in <i>Fusarium</i>: effects of physical and chemical processing

Biogeosciences ◽

10.5194/bg-16-4647-2019 ◽

2019 ◽

Vol 16 (23) ◽

pp. 4647-4659 ◽

Cited By ~ 3

Author(s):

Anna T. Kunert ◽

Mira L. Pöhlker ◽

Kai Tang ◽

Carola S. Krevert ◽

Carsten Wieder ◽

...

Keyword(s):

Fusarium Species ◽

Ice Nucleation ◽

Cumulative Number ◽

Genus Fusarium ◽

Biological Particles ◽

Ice Nuclei ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

The Impact ◽

Atmospherically Relevant

Abstract. Some biological particles and macromolecules are particularly efficient ice nuclei (IN), triggering ice formation at temperatures close to 0 ∘C. The impact of biological particles on cloud glaciation and the formation of precipitation is still poorly understood and constitutes a large gap in the scientific understanding of the interactions and coevolution of life and climate. Ice nucleation activity in fungi was first discovered in the cosmopolitan genus Fusarium, which is widespread in soil and plants, has been found in atmospheric aerosol and cloud water samples, and can be regarded as the best studied ice-nucleation-active (IN-active) fungus. The frequency and distribution of ice nucleation activity within Fusarium, however, remains elusive. Here, we tested more than 100 strains from 65 different Fusarium species for ice nucleation activity. In total, ∼11 % of all tested species included IN-active strains, and ∼16 % of all tested strains showed ice nucleation activity above −12 ∘C. Besides Fusarium species with known ice nucleation activity, F. armeniacum, F. begoniae, F. concentricum, and F. langsethiae were newly identified as IN-active. The cumulative number of IN per gram of mycelium for all tested Fusarium species was comparable to other biological IN like Sarocladium implicatum, Mortierella alpina, and Snomax®. Filtration experiments indicate that cell-free ice-nucleating macromolecules (INMs) from Fusarium are smaller than 100 kDa and that molecular aggregates can be formed in solution. Long-term storage and freeze–thaw cycle experiments revealed that the fungal IN in aqueous solution remain active over several months and in the course of repeated freezing and thawing. Exposure to ozone and nitrogen dioxide at atmospherically relevant concentration levels also did not affect the ice nucleation activity. Heat treatments at 40 to 98 ∘C, however, strongly reduced the observed IN concentrations, confirming earlier hypotheses that the INM in Fusarium largely consists of a proteinaceous compound. The frequency and the wide distribution of ice nucleation activity within the genus Fusarium, combined with the stability of the IN under atmospherically relevant conditions, suggest a larger implication of fungal IN on Earth’s water cycle and climate than previously assumed.

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Freezing nucleation apparatus puts new slant on study of biological ice nucleators in precipitation

Atmospheric Measurement Techniques ◽

10.5194/amt-7-129-2014 ◽

2014 ◽

Vol 7 (1) ◽

pp. 129-134 ◽

Cited By ~ 40

Author(s):

E. Stopelli ◽

F. Conen ◽

L. Zimmermann ◽

C. Alewell ◽

C. E. Morris

Keyword(s):

Light Transmission ◽

Freezing Temperature ◽

Partial Solution ◽

Ice Nucleation ◽

Precipitation Sample ◽

Ice Nucleators ◽

New Apparatus ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

Scatter Light

Abstract. For decades, drop-freezing instruments have contributed to a better understanding of biological ice nucleation and its likely implications for cloud and precipitation development. Yet, current instruments have limitations. Drops analysed on a cold stage are subject to evaporation and potential contamination. The use of closed tubes provides a partial solution to these problems, but freezing events are still difficult to be clearly detected. Here, we present a new apparatus where freezing in closed tubes is detected automatically by a change in light transmission upon ice development, caused by the formation of air bubbles and crystal facets that scatter light. Risks of contamination and introduction of biases linked to detecting the freezing temperature of a sample are then minimized. To illustrate the performance of the new apparatus we show initial results of two assays with snow samples. In one, we repeatedly analysed the sample (208 tubes) over the course of a month with storage at +4 °C, during which evidence for biological ice nucleation activity emerged through an increase in the number of ice nucleators active around −4 °C. In the second assay, we indicate the possibility of increasingly isolating a single ice nucleator from a precipitation sample, potentially determining the nature of a particle responsible for a nucleation activity measured directly in the sample. These two seminal approaches highlight the relevance of this handy apparatus for providing new points of view in biological ice nucleation research.

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IMPROVING ICE FORMATION BY ADDITIVE FOR COLD ENERGY STORAGE

International Journal of Air-Conditioning and Refrigeration ◽

10.1142/s2010132514500126 ◽

2014 ◽

Vol 22 (03) ◽

pp. 1450012 ◽

Cited By ~ 2

Author(s):

JIN HU ◽

OSMANN SARI ◽

CYRIL MAHMED

Keyword(s):

Heat Release ◽

Pseudomonas Syringae ◽

Freezing Temperature ◽

Ice Nucleation ◽

Ice Formation ◽

Nucleation Agent ◽

Cold Energy ◽

Nucleation Activity ◽

Effective Use ◽

Ice Nucleation Activity

Ice storage is one technique for effective use of thermal energy. Application of bionucleant (a protein from the bacterium Pseudomonas syringae) as a snow inducer in ski field has shown great potential to enhance the quantity of snow and increase freezing temperature. In this study, differential scanning calorimeter (DSC) and lab-built ice formation reactor were employed to study experimentally the heterogeneous ice nucleation under super-cooled conditions at different dissolved bionucleant concentrations. It was found the degree of supercooling is reduced by addition of bionucleant. However, ice nucleation-activity of bionucleant will drop down when bionucleant solution is saturated/supersaturated. In our DSC measured heat release study, when bionucleant acts as ice nucleation agent in aqueous solution, prior to reaching its saturation/supersaturation, there is an increase in latent heat release during freezing/melting as the amount of dissolved bionucleant increases. In another test, the supercooling does not occur in 0.5% bionucleant solution, it began to freeze around 0°C. Our results suggest that, the addition of bionucleant may help induce ice nucleation and increase freezing temperature thereby reduces the energy consumption of ice formation for cold storage.

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Freezing nucleation apparatus puts new slant on study of biological ice nucleators in precipitation

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-6-9163-2013 ◽

2013 ◽

Vol 6 (5) ◽

pp. 9163-9180 ◽

Cited By ~ 1

Author(s):

E. Stopelli ◽

F. Conen ◽

L. Zimmermann ◽

C. Alewell ◽

C. E. Morris

Keyword(s):

Light Transmission ◽

Freezing Temperature ◽

Partial Solution ◽

Ice Nucleation ◽

Precipitation Sample ◽

Ice Nucleators ◽

New Apparatus ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

Scatter Light

Abstract. Since decades, drop-freezing instruments have contributed to a better understanding of biological ice nucleation and its likely implications on cloud and precipitation development. Yet, current instruments have limitations. Drops analysed on a cold stage are subject to evaporation and potential contamination. The use of closed tubes provides a partial solution to these problems, but freezing events are still difficult to be clearly detected. Here, we present a new apparatus where freezing in closed tubes is detected automatically by a change in light transmission upon ice development, caused by the formation of air bubbles and crystal facets that scatter light. Risks of contamination and introduction of biases linked to detecting the freezing temperature of a sample are then minimized. To illustrate the performance of the new apparatus we show initial results of two assays with snow samples. In one, we repeatedly analysed the sample (208 tubes) over the course of a month with storage at +4 °C, during which evidence for biological ice nucleation activity emerged through an increase in the number of ice nucleators active around −4 °C. In the second assay, we indicate the possibility to increasingly isolate a single ice nucleator from a precipitation sample, potentially determining the nature of a particle responsible for a nucleation activity measured directly in the sample. These two seminal approaches highlight the relevance of this handy apparatus to provide new points of view in biological ice nucleation research.

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Seasonal ice nucleation activity of water samples from alpine rivers and lakes in Obergurgl, Austria

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.149442 ◽

2021 ◽

pp. 149442

Author(s):

Philipp Baloh ◽

Regina Hanlon ◽

Christopher Anderson ◽

Eoin Dolan ◽

Gernot Pacholik ◽

...

Keyword(s):

Water Samples ◽

Ice Nucleation ◽

Rivers And Lakes ◽

Nucleation Activity ◽

Alpine Rivers ◽

Ice Nucleation Activity

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Ice nucleation activity of iron oxides via immersion freezing and an examination of the high ice nucleation activity of FeO

Physical Chemistry Chemical Physics ◽

10.1039/d0cp04220j ◽

2021 ◽

Vol 23 (5) ◽

pp. 3565-3573

Author(s):

Esther Chong ◽

Katherine E. Marak ◽

Yang Li ◽

Miriam Arak Freedman

Keyword(s):

Iron Oxides ◽

Functional Groups ◽

Ice Nucleation ◽

Mechanical Processing ◽

Immersion Freezing ◽

Nucleation Activity ◽

Ice Nucleation Activity

FeO has enhanced ice nucleation activity due to functional groups that are exposed upon mechanical processing.

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The occurrence of ice nucleation activity in pathogenic bacterial species

Archives of Phytopathology and Plant Protection ◽

10.1080/03235408.2012.724970 ◽

2012 ◽

Vol 45 (18) ◽

pp. 2202-2212

Author(s):

Horst Mittelstädt

Keyword(s):

Bacterial Species ◽

Ice Nucleation ◽

Nucleation Activity ◽

Ice Nucleation Activity

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-10667-2012 ◽

2012 ◽

Vol 12 (22) ◽

pp. 10667-10677 ◽

Cited By ~ 66

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.

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