Sunday, 5 March 2017

Vitamin B12 and microbial growth

Scientists have found more evidence that vitamin B12, a substance produced by only a few organisms but needed by nearly all of them, wields great power in the microbial world. The findings lend credence to the idea that B12 helps shape microbial communities -- ubiquitous structures that affect energy and food production, the environment, human health, and many other processes.

A microbial research group made the findings in a bacterium known as Halomonas sp. HL-48, a rare supplier of the vitamin in its microbial community. The sample in the study hails from a microbial mat -- a community in which microbes band together in layers -- in Hot Lake in northern Washington state. The Hot Lake microbial mat has dozens of community members, living together and trading nutrients like carbon and oxygen in hot, salty water, thick with growth of algae and other micro-organisms.

Scientists have known that vitamin B12 controls crucial genes and enzymes in microbes involved in building DNA and proteins. But several scientists, including Andrew Goodman at Yale and Michiko Taga at University of California at Berkeley, have found indications that B12 wields even broader influence.

The researchers found that B12 interacts with 41 different proteins in the bacterium. They found that B12 is central to the regulation of folate, ubiquinone, and methionine -- substances crucial to the ability of microbial cells to create energy, build proteins, repair DNA, and to grow. The findings about methionine show an expanded influence of B12 compared to what has been known. The vitamin also changes the instructions it sends to genes depending on whether it's day or night -- not a surprise in a community of organisms for which light is a central driver.


Margaret F. Romine, Dmitry A. Rodionov, Yukari Maezato, Lindsey N. Anderson, Premchendar Nandhikonda, Irina A. Rodionova, Alexandre Carre, Xiaoqing Li, Chengdong Xu, Therese R. W. Clauss, Young-Mo Kim, Thomas O. Metz, Aaron T. Wright. Elucidation of roles for vitamin B 12 in regulation of folate, ubiquinone, and methionine metabolism. Proceedings of the National Academy of Sciences, 2017; 201612360 DOI: 10.1073/pnas.1612360114
Posted by Dr. Tim Sandle

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