The paper appears in the journal New Phytologist.

The scientists reviewed research on the photosynthetic amoeba Paulinella, which is a model to explore a fundamental question about eukaryote evolution: why was there a single origin of algae and plants? That is, why did photosynthesis by primary plastid endosymbiosis not originate multiple times in the tree of life?

Photosynthesis is the process by which plants and other organisms use sunlight to synthesize foods from carbon dioxide and water, which generates oxygen as a byproduct.

Endosymbiosis is a relationship between two organisms wherein one cell resides inside the other. This interaction, when stable and beneficial for the “host” cell, can result in massive genetic innovation. Despite its critical evolutionary role, there is limited knowledge about how endosymbiosis is initially established.

Primary plastid endosymbiosis, which evolved about 1.5 billion years ago, is the process in which a eukaryote — which are organisms such as plants and algae whose cells have a membrane-bound nucleus and tiny organs called organelles — engulfs a prokaryote, which are organisms such as bacteria that lack a membrane-enclosed nucleus. The plastid is a membrane-bound organelle within the cells of plants and algae.

“It turns out that photosynthesis results in enormous risks because it produces harmful chemicals and heat as byproducts that can damage the host cell,” said senior author Debashish Bhattacharya, a Distinguished Professor in the Department of Biochemistry and Microbiology at Rutgers University-New Brunswick. “Therefore, creating a novel organelle is a highly complex process that makes it fleetingly rare in evolution. Paulinella, which is the only known case of an independent plastid primary endosymbiosis other than in algae and plants, offers many clues to this process that helps explain why it is so rare.”

The origin of photosynthesis in algae and plants changed our planet by providing a major source of oxygen and supporting many ecosystems, due to their primary production, of fixed carbon (sugars and lipids). Understanding how this critical process happened will help us potentially engineer it in synthetic systems as well as to improve crop production.

“Because Paulinella is an independent origin of photosynthesis, it provides key clues to how this process occurs and what costs it imposes on the host cell,” said lead author Timothy G. Stephens, a postdoctoral researcher at Rutgers. “The genome of Paulinella contains many independently evolved genes involved in photosynthesis and dealing with the associated stresses that can potentially be engineered in algae and plants could help to improve their ability to withstand stresses such as high light levels or salt stress.”

The study included researchers from the Carnegie Institution.

Video: https://www.youtube.com/watch?v=Pbosfj1oV6I

Video: https://www.youtube.com/watch?v=nJ9ApL9Mq6w&t=3s

Story Source:

Materials provided by Rutgers University. Note: Content may be edited for style and length.

Now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Harvard Graduate School of Design have developed a deployable system that is light, compact, inexpensive, easy to manufacture, and, most importantly, easy to deploy. By harnessing the mechanical instabilities in curved beams, the system can transform objects into elaborate and customizable 3D configurations on a range of scales, from large-scale furniture to small medical devices.

“Most buckling-induced deployable structures, like folding chairs, are activated by compressive forces that are created through the linear displacement of elements,” said Saurabh Mhatre, a research associate at GSD and first author of the paper. “Our approach is different in that the compression force is generated through a rotational movement, which in turn induces buckling as the trigger for the 2D-to-3D transformation.”

The interdisciplinary research team of designers and engineers used a combination of experiments and numerical analyses to understand the geometry of curved, slender beams and what happens when those beams rotate and buckle. By harnessing buckling — a normally undesirable phenomenon in design and engineering — the researchers were able to design deployable structures with a simple rotational motion.

To demonstrate the system, the team built a lampshade that can be rotated to let in more or less light and a coffee table that can fold flat and pop-up in one simple motion.

“This new platform can be extended to realize functional structures and devices from the millimeter to meter scale using a variety of different materials,” said Katia Bertoldi, the William and Ami Kuan Danoff Professor of Applied Mechanics at SEAS and senior author of the study. “These structures could be used as medical devices, optical devices like camera focusing mechanisms, deployable wheels and turbines, furniture, or deployable shelters.”

The research was published recently in Advanced Materials. It was co-authored by Elisa Boatti, David Melancon, Ahmad Zareei, Maxime Dupont and Martin Bechthold. It was supported in part by the National Science Foundation through the Harvard University Materials Research Science and Engineering Center under grants DMR2011754 and DMR-1922321.

The UC-led study, conducted in collaboration with the Karolinska Institute in Sweden, claims that the treatment of Alzheimer’s disease might lie in normalizing the levels of a specific brain protein called amyloid-beta peptide. This protein is needed in its original, soluble form to keep the brain healthy, but sometimes it hardens into “brain stones” or clumps, called amyloid plaques.

The study, which appears in the journal EClinicalMedicine (published by the Lancet), comes on the heels of the FDA’s conditional approval of a new medicine, aducanumab, that treats the amyloid plaques.

“It’s not the plaques that are causing impaired cognition,” says Alberto Espay, the new study’s senior author and professor of neurology at UC. “Amyloid plaques are a consequence, not a cause,” of Alzheimer’s disease, says Espay, who is also a member of the UC Gardner Neuroscience Institute.

Alzheimer’s disease became widely known as “the long goodbye” in the late 20th century due to the disease’s slow deterioration of brain function and memory. It was over 100 years ago, however, that scientist Alois Alzheimer first identified plaques in the brain of patients suffering from the disease.

Since then, Espay says that scientists have focused on treatments to eliminate the plaques. But the UC team, he says, saw it differently: Cognitive impairment could be due to a decline in soluble amyloid-beta peptide instead of the corresponding accumulation of amyloid plaques. To test their hypothesis, they analyzed the brain scans and spinal fluid from 600 individuals enrolled in the Alzheimer’s Disease Neuroimaging Initiative study, who all had amyloid plaques. From there, they compared the amount of plaques and levels of the peptide in the individuals with normal cognition to those with cognitive impairment. They found that, regardless of the amount of plaques in the brain, the individuals with high levels of the peptide were cognitively normal.

They also found that higher levels of soluble amyloid-beta peptide were associated with a larger hippocampus, the area of the brain most important for memory.

According to the authors, as we age most people develop amyloid plaques, but few people develop dementia. In fact, by the age of 85, 60% of people will have these plaques, but only 10% develop dementia, they say.

“The key discovery from our analysis is that Alzheimer’s disease symptoms seem dependent on the depletion of the normal protein, which is in a soluble state, instead of when it aggregates into plaques,” says co-author Kariem Ezzat from the Karolinska Institute.

The most relevant future therapeutic approach for the Alzheimer’s program will be replenishing these brain soluble proteins to their normal levels, says Espay.

The research team is now working to test their findings in animal models. If successful, future treatments may be very different from those tried over the last two decades. Treatment, says Espay, may consist of increasing the soluble version of the protein in a manner that keeps the brain healthy while preventing the protein from hardening into plaques.

Co-authors include: Andrea Sturchio, University of Cincinnati, and Samir EL Andaloussi, Karolinska Institute.

The research was funded by the UC Gardner Neuroscience Institute.

The authors disclose that they have recently cofounded REGAIN Therapeutics, owner of a patent application that covers synthetic soluble non-aggregating peptide analogues as replacement treatment in proteinopathies.

Story Source:

Materials provided by University of Cincinnati. Original written by Angela Koenig. Note: Content may be edited for style and length.