A species of chlorella lives on the Antarctic continent. It drifted from the temperate zone through the atmospheric laminar flow long ago. When those chlorella from temperate zones reached the cold Antarctic continent that year, why weren't they frozen to death? After more than 10 years of research, researchers in China have uncovered the mystery.
Chlorella is a microalga. Researchers from the Institute of Hydrobiology of the Chinese Academy of Sciences and other institutions have used chlorella NJ-7 isolated from Antarctica and chlorella UTEX259 from temperate zones as research materials, revealing the early adaptation mechanism of microalgae in the Antarctic environment.
According to experts, chlorella NJ-7 and UTEX259 have very similar genetic information. They grow similarly at 20 degrees Celsius, but NJ-7 can grow at 4 degrees Celsius, but UTEX259 cannot. At the same time, NJ-7's anti-freezing ability is much stronger than that of UTEX259, and it can endure the cold of minus 20 degrees Celsius. Fossil calibration analysis evolution time shows that the separation time of NJ-7 and UTEX259 was about 2.6 million years ago, much later than when the Antarctic continent separated from South America.
The Xu Xudong research team of the Institute of Aquatic Sciences of the Chinese Academy of Sciences found that the adaptive evolution of Antarctic chlorella was mainly based on the increase of LEA protein and various enzyme levels, and the positive direction of some enzymes through a systematic in-depth analysis of the genome, transcriptome and quantitative proteome. select. The accumulation of LEA protein keeps it alive under freezing conditions, and systematically increasing the content of key enzymes directly leads to an increase in enzyme activity, which makes Chlorella first-arrival in Antarctica maintain its metabolic activity and gain growth ability under conditions close to zero degrees Celsius. Surprisingly, most of these enzymes and proteins that have increased content in Antarctica strains are not induced by low temperature.
Xu Xudong said that this study for the first time revealed the early adaptation mechanism of microalgae in the Antarctic environment, and initially answered the question of how cells maintain high enzyme activity before the enzyme completes cold adaptation, and how microbes, lower plants and animals adapt to Antarctica. Environmental and other related research has important reference value.
The research results have recently been published online in the internationally renowned journal "Molecular Biology and Evolution" in the field of evolutionary biology.
Article source: Xinhuanet