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Category: chemistry – Page 255

Building on the moon and Mars? You’ll need extraterrestrial cement for that

Sustained space exploration will require infrastructure that doesn’t currently exist: buildings, housing, rocket landing pads.

So, where do you turn for construction materials when they are too big to fit in your carry-on and there’s no Home Depot in outer space?

“If we’re going to live and work on another planet like Mars or the moon, we need to make concrete. But we can’t take bags of concrete with us—we need to use local resources,” said Norman Wagner, Unidel Robert L. Pigford Chair of Chemical and Biomolecular Engineering at the University of Delaware.

MIT researchers discover bacteria’s new antiviral defense system

Specific proteins in prokaryotes detect viruses in unexpectedly direct ways.

Bacteria use a variety of defense strategies to fight off viral infection. STAND ATPases in humans are known to respond to bacterial infections by inducing programmed cell death in infected cells. Scientists predict that many more antiviral weapons will be discovered in the microbial world in the future. Scientists have discovered a new unexplored microbial defense system in bacteria.

Researchers uncovered specific proteins in prokaryotes (bacteria and archaea) that detect viruses in unexpectedly direct ways, recognizing critical parts of the viruses and causing the single-celled organisms to commit suicide to stop the infection within a microbial community, according to a press release published in the official website of the Massachusetts Institute of Technology (MIT) on Thursday.

The discovery was made by a team of scientists led by researchers at the Broad Institute of MIT and Harvard and the McGovern Institute for Brain Research at MIT.

“This work demonstrates a remarkable unity in how pattern recognition occurs across very different organisms,” said Feng Zhang, senior author and James, and Patricia Poitras Professor of Neuroscience at MIT.

“It’s been very exciting to integrate genetics, bioinformatics, biochemistry, and structural biology approaches in one study to understand this fascinating molecular system.”

Bacteria use a variety of defense strategies to fight off viral infection, and some of these systems have led to groundbreaking technologies, such as CRISPR-based gene editing.

Continue reading “MIT researchers discover bacteria’s new antiviral defense system” | >

Meteorites may have helped seed life on Earth

Circa 2017

There are many theories about how life evolved on the planet Earth, from formation under a layer of ice, protected from the UV radiation above, to vents in the deep sea that provided hydrogen-rich molecules. But now one team of scientists has found quantitative results that support a theory that is literally out of this world. Organic molecules from meteorites that landed in small, warm pools of water may have delivered the ingredients necessary for life to form on Earth.

The team reached this conclusion through a mathematical model. They took data about planet formation, geology, biology and chemistry and inputted these factors into a grand quantitative model they had designed. Their results support the theory that RNA polymers formed in small, warm ponds of water. Meteorites contributed to this process by transferring enough organic molecules to these pools to ensure that RNA started self-replicating in at least one pool.

What’s more, the team discovered that, according to their calculations, life may have have begun on Earth rather early. The process may have started just a few hundred million years after the planet cooled sufficiently to support liquid surface water. The results were published in Proceedings of the National Academy of Sciences.

Scientists win 2015 Nobel Prize for Chemistry for work on DNA repair

Circa 2015

“Their work has provided fundamental knowledge of how a living cell functions and is, for instance, used for the development of new cancer treatments,” the Royal Swedish Academy of Sciences said.

Thousands of alterations to a cell’s genome occur every day due to spontaneous changes and damage by radiation, free radicals and carcinogenic substances — yet DNA remains astonishingly intact.

To keep genetic materials from disintegrating, a range of molecular systems monitor and repair DNA, in processes that the three award-winning scientists helped map out.

Researchers create algorithm to help predict cancer risk associated with tumor variants

Vanderbilt researchers have developed an active machine learning approach to predict the effects of tumor variants of unknown significance, or VUS, on sensitivity to chemotherapy. VUS, mutated bits of DNA with unknown impacts on cancer risk, are constantly being identified. The growing number of rare VUS makes it imperative for scientists to analyze them and determine the kind of cancer risk they impart.

Traditional prediction methods display limited power and accuracy for rare VUS. Even machine learning, an artificial intelligence tool that leverages data to “learn” and boost performance, falls short when classifying some VUS. Recent work by the lab of Walter Chazin, Chancellor’s Chair in Medicine and professor of biochemistry and chemistry, led by co-first authors and postdoctoral fellows Alexandra Blee and Bian Li, featured an active machine learning technique.

Active machine learning relies on training an algorithm with existing data, as with machine learning, and feeding it new information between rounds of training. Chazin and his lab identified VUS for which predictions were least certain, performed biochemical experiments on those VUS and incorporated the resulting data into subsequent rounds of algorithm training. This allowed the model to continuously improve its VUS classification.

New Molecule Discovered That Strongly Stimulates Hair Growth

A team at the University of California, Irvine, has identified a signaling molecule that potently stimulates hair growth.

A signaling molecule known as SCUBE3, which was discovered by researchers at the University of California, Irvine, has the potential to cure androgenetic alopecia, a prevalent type of hair loss in both women and men.

The research, which was recently published in the journal Developmental Cell, uncovered the precise mechanism by which the dermal papilla cells, specialized signal-producing fibroblasts found at the bottom of each hair follicle, encourage new development. Although the critical role dermal papilla cells play in regulating hair growth is widely established, the genetic basis of the activating chemicals involved is little understood.

Researchers develop artificial synapse that works with living cells

In 2017, Stanford University researchers presented a new device that mimics the brain’s efficient and low-energy neural learning process. It was an artificial version of a synapse—the gap across which neurotransmitters travel to communicate between neurons—made from organic materials. In 2019, the researchers assembled nine of their artificial synapses together in an array, showing that they could be simultaneously programmed to mimic the parallel operation of the brain.

Now, in a paper published June 15 in Nature Materials, they have tested the first biohybrid version of their artificial synapse and demonstrated that it can communicate with living cells. Future technologies stemming from this device could function by responding directly to chemical signals from the brain. The research was conducted in collaboration with researchers at Istituto Italiano di Tecnologia (Italian Institute of Technology—IIT) in Italy and at Eindhoven University of Technology (Netherlands).

“This paper really highlights the unique strength of the materials that we use in being able to interact with living matter,” said Alberto Salleo, professor of materials science and engineering at Stanford and co-senior author of the paper. “The cells are happy sitting on the soft polymer. But the compatibility goes deeper: These materials work with the same molecules neurons use naturally.”

An artificial neuron that can receive and release dopamine

A team of researchers from Nanjing University of Posts and Telecommunications and the Chinese Academy of Sciences in China and Nanyang Technological University and the Agency for Science Technology and Research in Singapore developed an artificial neuron that is able to communicate using the neurotransmitter dopamine. They published their creation and expected uses for it in the journal Nature Electronics.

As the researchers note, most machine-brain interfaces rely on as a communications medium, and those signals are generally one-way. Electrical signals generated by the brain are read and interpreted; signals are not sent to the brain. In this new effort, the researchers have taken a step toward making a that can communicate in both directions, and it is not based on electrical signals. Instead, it is chemically mediated.

The work involved building an artificial neuron that could both detect the presence of dopamine and also produce dopamine as a response mechanism. The neuron is made of graphene (a single sheet of carbon atoms) and a carbon nanotube electrode (a single sheet of carbon atoms rolled up into a tube). They then added a sensor capable of detecting the presence of dopamine and a device called a memristor that is capable of releasing dopamine using a heat-activated hydrogel, attached to another part of their artificial neuron.

Scientists hid encryption key for Wizard of Oz text in plastic molecules

It’s “a revolutionary scientific advance in molecular data storage and cryptography.”

Scientists from the University of Texas at Austin sent a letter to colleagues in Massachusetts with a secret message: an encryption key to unlock a text file of L. Frank Baum’s classic novel The Wonderful Wizard of Oz. The twist: The encryption key was hidden in a special ink laced with polymers, They described their work in a recent paper published in the journal ACS Central Science.

When it comes to alternative means for data storage and retrieval, the goal is to store data in the smallest amount of space in a durable and readable format. Among polymers, DNA has long been the front runner in that regard. As we’ve reported previously, DNA has four chemical building blocks—adenine (A), thymine (T), guanine (G), and cytosine ©—which constitute a type of code. Information can be stored in DNA by converting the data from binary code to a base-4 code and assigning it one of the four letters. A single gram of DNA can represent nearly 1 billion terabytes (1 zettabyte) of data. And the stored data can be preserved for long periods—decades, or even centuries.

There have been some inventive twists on the basic method for DNA storage in recent years. For instance, in 2019, scientists successfully fabricated a 3D-printed version of the Stanford bunny—a common test model in 3D computer graphics—that stored the printing instructions to reproduce the bunny. The bunny holds about 100 kilobytes of data, thanks to the addition of DNA-containing nanobeads to the plastic used to 3D print it. And scientists at the University of Washington recently recorded K-Pop lyrics directly onto living cells using a “DNA typewriter.”