From Paulson: “Cellular division strategy shared across all domains of life”

Harvard School of Engineering and Applied Sciences
John A Paulson School of Engineering and Applied Sciences

December 18, 2017
Leah Burrows
lburrows@seas.harvard.edu
(617) 496-1351

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SEAS researchers have found that these pink-hued archaea — called Halobacterium salinarum — use the same mechanisms to maintain size as bacteria and eukaryotic life, indicting that cellular division strategy may be shared across all domains of life. (Image courtesy of Alexandre Bison/Harvard University)

The three domains of life — archaea, bacteria, and eukarya — may have more in common than previously thought.

Over the past several years, Ariel Amir, Assistant Professor in Applied Mathematics at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has been studying how cells regulate size. In previous research, he and his collaborators found that E. coli (bacteria) and budding yeast (eukaryote) use the same cellular mechanisms to ensure uniform cell sizes within a population.

Now, with a team of collaborators including Ethan Garner, the John L. Loeb Associate Professor of the Natural Sciences at Harvard, and Amy Schmid, Assistant Professor of biology at Duke University, Amir found that archaea use the very same mechanism.

The research is published in Nature Microbiology.

“These findings raise really interesting questions about how cellular mechanics evolved independently across all three domains of life,” said Amir. “Our results will serve as a useful foundation for, ultimately, understanding the molecular mechanisms and evolution of cell cycle control.”

Archaea are single-celled microorganisms that inhabit some of Earth’s most extreme environments, such as volcanic hot springs, oil wells and salt lakes. They are notoriously difficult to cultivate in a lab and, as such, are relatively understudied.

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Archaea inhabit some of Earth’s most extreme environments, such as this salt lake in Bolivia (Image courtesy of Ariel Amir/Havard SEAS)

“Archaea are unique because they blend a lot of the characteristics of both bacteria and eukaryotes,” said Dr. Yejin Eun, first author of the paper. “Archaea resemble bacterial cells in size and shape but their cell cycle events — such as division and DNA replication — are a hybrid between eukaryotes and bacteria.”

The researchers studied Halobacterium salinarum, an extremophile that lives in high-salt environments. They found that like bacteria and budding yeast, H. salinarum controls its size by adding a constant volume between two events in the cell cycle. However, the researchers found that H. salinarum are not as precise as E.coli and there was more variability in cell division and growth than in bacterial cells.

“This research is the first to quantify the cellular mechanics of size regulation in archaea,” said Amir. “This allows us to quantitatively explore how these mechanisms work, and build a model that explains the variability within the data and the correlations between key properties of the cell cycle. Eventually, we hope to understand just what makes this cellular mechanism so popular across all domains of life.”

This research was also coauthored by Po-Yi Ho, Minjeong Kim, Lars Renner, Salvatore LaRussa, and Lydia Robert.

This research was supported in part by the National Institute of Health and the National Science Foundation.

See the full article here .

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Through research and scholarship, the Harvard School of Engineering and Applied Sciences (SEAS) will create collaborative bridges across Harvard and educate the next generation of global leaders. By harnessing the power of engineering and applied sciences we will address the greatest challenges facing our society.

Specifically, that means that SEAS will provide to all Harvard College students an introduction to and familiarity with engineering and technology as this is essential knowledge in the 21st century.

Moreover, our concentrators will be immersed in the liberal arts environment and be able to understand the societal context for their problem solving, capable of working seamlessly withothers, including those in the arts, the sciences, and the professional schools. They will focus on the fundamental engineering and applied science disciplines for the 21st century; as we will not teach legacy 20th century engineering disciplines.

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To address current and future societal challenges, knowledge from fundamental science, art, and the humanities must all be linked through the application of engineering principles with the professions of law, medicine, public policy, design and business practice.

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Ultimately, we will provide to our graduates a rigorous quantitative liberal arts education that is an excellent launching point for any career and profession.