2018 Fiscal Year Research-status Report
Microbial Communities in the Sea Surface Microlayer as a Potential Source of Biogenic Ice Nuclei in Oceanic Regions
| Project/Area Number |
18K14787
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
WONG SHUKUAN 東京大学, 大気海洋研究所, 特任研究員 (60808400)
|
|---|
| Project Period (FY) |
2018-04-01 – 2020-03-31
|
| Keywords | Ice nucleation activity / Sea Surface Microlayer |
|---|
| Outline of Annual Research Achievements |
Ice-nucleating bacteria have the ability to freeze at warmer temperatures with some as warm as -2 Celcius. We had isolated 157 bacterial strains from the sea surface microlayer,seawater and seafoam. The ice nucleation activity of the isolated bacterial strains were tested using the drop-down freezing assay. A total of 67 bacterial isolates had been tested for their ice nucleating activities using the freeze-drop test. 57 isolates showed no ice-nucleation potential; 54 isolates froze at -20 Celcius, the temperatures where the negative control started to freeze while three isolates froze at temperatures lower than the negative control. Three isolates were ice-nucleation positive at temperatures of -10to-11 Celcius.
|
| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
We will continue to test the ice nucleating ability of the remaining 90 isolates.
Once, we have identified and obtained positive ice nucleating bacterial strains from our environmental samples, we will be able to proceed with the next step in streamlining the PCR primers and conditions for use with environmental DNA samples.
|
| Strategy for Future Research Activity |
In the next fiscal year, we will continue to test the ice nucleating ability of the remaining 90 isolates. We will then conduct PCR on the INA positive strains using P.agglomerans and P.syringae as positive control. The PCR conditions will be optimized and further tested using environmental samples (sea surface microlayer, seawater and seafoam). If we succeed in amplifying the environmental samples using the PCR primers and conditions tested above, the amplified environmental samples will be sequenced using next generation sequencer to identify the INA bacteria more efficiently at a larger scale.
|
