Nature Microbiology Zhang Yuzhong's team reveals a new mechanism of marine bacteria's organic sulfur metabolism and defense

Responsibility Editor | xi The predation and defense between predators and prey is one of the important interactions in the field of microbes.
The chemical defense mechanism that bacteria produce biologically toxic substances to resist predation is widely present in the marine system
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Therefore, the analysis of the molecular mechanism of the anti-predator function of toxic substances is essential for a comprehensive understanding of the interactions between organisms in marine micro-ecosystems
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Dimethylmercaptopropionic acid inner salt (DMSP) is one of the most abundant organic sulfur compounds in marine ecosystems.
It is an important participant in the global sulfur cycle and potentially participates in global climate regulation
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In addition, DMSP also performs many important physiological and ecological functions
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Previous studies have shown that when the algae is preyed, the ruptured algae produces high concentrations of toxic acrylic acid through the DMSP released by lysis, which can resist further predation by algae-eating zooplankton.
However, it is still unclear whether there is a similar defense mechanism in bacteria.

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On October 25, 2021, the team of Professor Zhang Yuzhong from Ocean University of China and Shandong University, in cooperation with the University of Warwick, the Yantai Institute of Coastal Zone Research of the Chinese Academy of Sciences, Sun Yat-sen University and other units published an article Acrylate protects a marine bacterium from grazing by Nature Microbiology a ciliate predator, reveals the chemical defense mechanism of marine bacteria cracking the inner salt of dimethylmercaptopropionic acid to produce acrylic acid to resist ciliate predation
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Under the guidance of Professor Zhang Yuzhong, the research team’s doctoral students Teng Zhaojie, Associate Professor Wang Peng, Professor Chen Xiulan and others discovered that marine bacteria can cleave DMSP in the periplasmic space under the action of the DMSP lyase DddL to produce and accumulate acrylic acid to resist ciliary predation.
, And make the ciliates transfer the predation pressure to the bacteria in the community that does not contain the dddL gene, so as to obtain a competitive advantage in resources and space
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The marine bacterium Puniceibacterium antarcticum SM1211 uses DMSP as a precursor for chemical defense strategies.
The researchers selected the marine strain Puniceibacterium antarcticum SM1211 containing the membrane protein DddL as the main research strain, and revealed the mechanism of the bacteria accumulating acrylic acid outside the cell
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On this basis, the researchers established the basic predation system by using the ciliate marine cervix and the strain SM1211 as prey and predator respectively
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Through ecological predation experiments, it is found that in the presence of DMSP, strain SM1211 can produce acrylic acid by cracking DMSP, reducing the short-term predation efficiency and long-term growth rate of marine worms, and at the same time, it can also affect the predation of marine worms.
The selectivity makes the predation pressure transfer to the bacteria that do not contain the dddL gene in the bacterial community, thereby improving the survival rate of strain SM1211 during the predation process, adjusting the composition of the bacterial community and the energy flow between different nutrient levels
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This research system reveals a new mechanism for marine bacteria to use DMSP as a precursor material to play an anti-predator function, laying a foundation for in-depth exploration of the interactions between organisms in marine micro-ecosystems
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Original link: https://doi.
org/10.
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