New discovery sheds light on key photosynthetic substance

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A latest study on methane-forming archaea led by Virginia Tech and University of California, Berkeley have discovered that a process that triggers photosynthesis in plants likely developed on Earth in ancient microbes 2.5 billion years ago.

The research offers new outlook on evolutionary microbiology, biology, and the production of natural gas, and may shed light on climate change, agriculture, and human health.

Archaea, are simple, single-celled organisms that can live in extreme environments. They are separate from prokaryotes and eukaryotes. Archaea is a group of microbes called methanogens, which reside in oxygen-deprived areas.

“By looking at this one mechanism that was not previously studied, we will be able to develop new basic information that potentially has broad impact on contemporary issues ranging from climate change to obesity,” senior author Biswarup Mukhopadhyay, an associate professor of biochemistry at the Virginia Tech College of Agriculture and Life Sciences, in a statement. He is also a faculty member at the Virginia Bioinformatics Institute. Plant and microbial biology professor emeritus Bob B. Buchanan co-led the research and co-authored the paper.

The study’s findings were described this week in an early online edition of the Proceedings of the National Academy of Sciences.

“This innovative work demonstrates the importance of a new global regulatory system in methanogens,” said William Whitman, a professor of microbiology at the University of Georgia. “Understanding this system will provide the tools to use these economically important microorganisms better.”

The study focused at Methanocaldococcus jannaschii, which lives in conditions that impersonate ancient earth, such as hydrothermal vents or volcanoes.

The microbe has been found containing protein thioredoxin. Thioredoxin plays a significant role in photosynthesis, and helps the organism repair the damage caused by oxygen.

The researchers said thioredoxin-based metabolic regulation can aid anaerobes (living without oxygen) endure tough conditions on earth before the arrival of oxygen.

Methanogens play a key role in carbon cycling. The process in which plants die and a part of their biomass gets trapped in oxygen deprived areas. Methanogens help transform the leftover biological material to methane, which other organisms change to carbon dioxide. Methanogens are also found in the digestive systems of cattle and sheep where they support digestion.

A previous study published in The American Journal of Gastroenterology Supplements in 2012 suggested that methanogens oxidize hydrogen to produce methane and supply more complete fermentation of carbohydrate substrates whose outcome is higher generation and absorption of short-chain fatty acids, which may cause obesity.

This natural process for producing methane is the foundation for treating municipal and industrial wastes, helps trim down pollution, and provides methane for fuel. The same process allows natural gas production from agricultural residues, a renewable resource.