| Budget Amount *help |
¥16,380,000 (Direct Cost: ¥12,600,000、Indirect Cost: ¥3,780,000)
Fiscal Year 2016: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2015: ¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2014: ¥6,890,000 (Direct Cost: ¥5,300,000、Indirect Cost: ¥1,590,000)
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| Outline of Final Research Achievements |
Humic acid (HA) is one of the major components of soil humic substance while little is known about interaction between HA and soil microorganisms. This study indicated that tens of filamentous fungi absorb HA, and metabolize HA to high-molecular weight compounds in laboratory-scale cultures. A culture of the model filamentous fungus Aspergillus nidulans, which we found efficiently metabolizes HA, converted HA to more oxidized compounds with higher content of phenol and carboxy moieties. Transcriptome of the fungus cultured in the presence of HA indicated that HA altered global transcription of the fungus. Biochemical studies indicated that HA switched the fungal respiration mechanism to cyanide-resistant one, and stimulated cell growth under the culture conditions. These results presented novel examples of physiological interaction between HA and soil microorganisms, and impacts homeostasis of terrestrial HA that is mediated by natural microorganisms.
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