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In English
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In a scientific breakthrough, researchers from Inha University, led by Prof. Jang-Cheon Cho, have successfully cultured and identified the elusive bacteria known as SAR202 in the Yellow Sea. The research was published on August 22 in Nature Communications.
This enigmatic SAR202 bacteria, first identified in the Sargosso Sea in the early 1990s by Prof. Steve Giovannoni (Oregon State University), are ubiquitously distributed in the ocean, comprising up to 30% of the deep-sea microbial community. However, they have not yet been cultivated in the lab.
The successful cultivation was achieved by preparing a specialized growth medium using natural seawater from Garolim Bay. Notably, the cultured cells exhibited an unusually slow growth rate, dividing only once every three days, and they could not grow when exposed to light. The research team also uncovered another intriguing aspect of SAR202 bacteria—they are the first known bacterial group to possess the ability to synthesize an archaellar motor, a feature previously thought to be exclusive to archaea. Moreover, SAR202 cells contain paralog expansions, including 80 enolase superfamily genes, and actively grew on substrates suitable for these enzymes. The team named the bacteria "Lucifugimonas marina," signifying their preference for darkness.
Prof. Cho remarked, “The significance of our achievement lies in successfully cultivating bacteria that have intrigued microbiologists worldwide for decades. This discovery opens doors for further exploration, particularly in unraveling the roles of the numerous catabolic enzyme paralogous for organic compounds degrdation.“
(left) SAR202 bacteria, which grow very slowly, are inhibited by light exposure.
(right) Donut-shaped bacteria photographed by scanning electron microscopy.
[Reference] Lim Y. et al., (2023) “Cultivation of marine bacteria of the SAR202 clade.” Nature Communications 14:5098.
[Main Author] Yeonjung Lim (Inha University), Ilnam Kang (Inha University), Jang-Cheon Cho (Inha University)
* Contact email : Prof. Jang-Cheon Cho (chojc@inha.ac.kr)