Marine bacteria work together to produce important vitamins

A German-American research team led by microbiologist Dr. Gerrit Wienhausen from the University of Oldenburg, Germany, has taken an important step towards understanding the highly complex interactions between marine microorganisms. The researchers carried out various experiments to analyze the interaction between two species of marine bacteria from the North Sea in the synthesis of vitamin B12 and published their results in the journal. Nature.

Vitamin B12 is essential but scarce in the ocean (and elsewhere). This is essential not only for the metabolism of the two bacteria investigated in this study, but also for many other marine organisms. “Half of all algae cannot survive without this vitamin,” Wienhausen explains. However, like humans, algae cannot produce B12 on their own. So researchers at Oldenburg University and the Scripps Institution of Oceanography in San Diego (USA) were eager to take a closer look at B12 synthesis in marine bacteria.

Although certain bacterial strains are known as vitamin B12 producers, this research project focused on two strains of the genera Roseobarius and Colwellia, each of which produces only one of the two components of vitamin B12. I guessed. other.

“It’s interesting how complex the interactions between bacteria are,” Professor Wienhausen emphasizes regarding this new study. The study was carried out as part of the Roseobacter Collaborative Research Center, headed by Oldenburg microbiologist Dr. Meinhard Simon. Current publications.

Complex interactions between two bacterial strains

Using complex laboratory experiments and cutting-edge analytical tools, the researchers were able to investigate the interaction between the two bacterial strains in detail. According to their findings, bacteria in Colwellia strain M166 synthesize smaller components of vitamin B12 and release them into the surrounding water. The bacteria of the Roseobarius strain M141 not only produce the larger component that is the main component, but also can synthesize the B12 that both bacterial strains require from the combination of their two components.

However, the Roseobarius strain does not release the vitamin on its own, but only when Colwellia activates the virus encoded in its co-producer’s bacterial genome and the virus multiplies. The resulting viral infection causes some of the affected Roseobarius bacteria to rupture, releasing vitamin B12 along with the virus, making it available to Colwellia (and possibly other marine life as well).

“This fine-tuned cross-supply of metabolic components and products may be relevant not only to marine microbial communities but also to other ecosystems,” said Oldenburg Institute of Marine Environmental Chemistry and Biology (ICBM). ) said Scripps researchers. Marine Research Institute report.

“We were able to demonstrate for the first time that two bacteria synthesize B12 only in cooperation with each other,” says Wienhausen. “Such a complex form of interaction between bacteria was previously unknown.”

More than 60 researchers from Oldenburg, Braunschweig, Göttingen and Bonn have investigated bacteria of the Roseobacter group within the Cross-Regional Collaborative Research Center (CRC) Roseobacter over the past 13 years.

These bacteria are present in all marine habitats, from the tropics to the polar oceans, and from the ocean surface to the deep sea. Among other achievements, the researchers discovered many new species and described their distribution and functional biogeography in the world’s oceans for the first time. More than 280 scientific papers based on research conducted within the context of the CRC have been published to date.