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Category: genetics – Page 421

Dynamic DNA material with emergent locomotion behavior powered by artificial metabolism

Interesting research paper on a new nanobot technology. I’m watching for ways in which suitable substrates for mind uploading can be constructed, and DNA self-guided assembly has potential.

Here are some excerpts and a weblink to the paper:

“…Chemical approaches have opened synthetic routes to build dynamic materials from scratch using chemical reactions, ultimately allowing flexibility in design…”

… As a realization of this concept, we engineered a mechanism termed DASH—DNA-based Assembly and Synthesis of Hierarchical materials—providing a mesoscale approach to create dynamic materials from biomolecular building blocks using artificial metabolism. DASH was developed on the basis of nanotechnology that uses DNA as a generic material ranging from nanostructures to hydrogels, for enzymatic substrates, and as linkers between nanoparticles…”

“…Next, to illustrate the potential uses of self-generated materials, we created various hybrid functional materials from the DASH patterns. The DASH patterns served as a versatile mesoscale scaffold for a diverse range of functional nanomaterials beyond DNA, ranging from proteins to inorganic nanoparticles, such as avidin, quantum dots, and DNA-conjugated gold nanoparticles (AuNPs) (Fig. 4D, figs. S37 and S38, and Supplementary Text). The generated patterns were also rendered functional with catalytic activity when conjugated with enzymes (figs. S39 and S40 and Supplementary Text). We also showed that the DNA molecules within the DASH patterns retained the DNA’s genetic properties and that, in a cell-free fashion, the materials themselves successfully produced green fluorescent proteins (GFPs) by incorporating a reporter gene for sfGFP (Fig. 4E and figs. S9 and S41) (40). The protein production capability of the materials established the foundation for future cell-free production of proteins, including enzymes, in a spatiotemporally controlled manner.

…” Our implementation of the concept, DASH, successfully demonstrated various applications of the material. We succeeded in constructing machines from this novel dynamic biomaterial with emergent regeneration, locomotion, and racing behaviors by programming them as a series of FSAs. Bottom-up design based on bioengineering foundations without restrictions of life fundamentally allowed these active and programmable behaviors. It is not difficult to envision that the material could be integrated as a locomotive ele-ment in biomolecular machines and robots. The DASH patterns could be easily recognized by naked eyes or smartphones, which may lead to better detection technologies that are more feasible in point-of-care settings. DASH may also be used as a template for other materials, for example, to create dynamic waves of protein expression or nanoparticle assemblies. In addition, we envision that further expansion of artificial metabolism may be used for self-sustaining structural components and self-adapting substrates for chemical production pathways. Ultimately, our material may allow the construction of self-reproducing machines through the production of enzymes from generated materials that, in turn, reproduce the material. Our biomaterial powered by artificial metabolism is an important step toward the creation of “artificial” biological systems with dynamic, life-like capabilities.”…

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US$30 Million to Seed Hundreds of Bold, Innovative Ideas for Human Longevity! — Dr. Victor Dzau, President of the U.S. National Academy of Medicine — Healthy Longevity Global Grand Challenge — ideaXme — Ira Pastor

Missing protein in brain causes behaviors mirroring autism

Scientists at Rutgers University-Newark have discovered that when a key protein needed to generate new brain cells during prenatal and early childhood development is missing, part of the brain goes haywire—causing an imbalance in its circuitry that can lead to long-term cognitive and movement behaviors characteristic of autism spectrum disorder.

“During , there is a coordinated series of events that have to occur at the right time and the right place in order to establish the appropriate number of cells with the right connections,” said Juan Pablo Zanin, Rutgers-Newark research associate and lead author on a paper published in the Journal of Neuroscience.” Each of these steps is carefully regulated and if any of these steps are not regulated correctly, this can impact behavior.”

Zanin has been working with Wilma Friedman, professor of cellular neurobiology in the Department of Biological Sciences, studying the p75NTR —needed to regulate —to determine its exact function in brain development, gain a better understanding of how this genetic mutation could cause to die off and discover whether there is a genetic link to autism or like Alzheimer’s.

The connection between ribosomes and telomeres in plants

Findings from a recent research project, conducted by a Marshall University scientist and assistant professor in the Marshall University College of Science, with researchers in Texas, was recently published in the December issue of the prestigious online journal, Nature Communications.

Dr. Eugene Shakirov is studying the connection between ribosomes and telomeres in plants. Telomeres are the physical ends of chromosomes and they shorten with age in most cells. Accelerated shortening of telomeres is linked to age-related diseases and overly long telomeres are often linked to cancer.

Telomere length varies between individuals at birth and is known to predetermine cellular lifespan, but the genes establishing length variations are largely unknown. The research being done by Shakirov, along with collaborators at the University of Texas at Austin, Texas A&M University, HudsonAlpha Institute for Biology and the Kazan Federal University in Russia focused on the study of the genetic and epigenetic causes of natural telomere length variation in Arabidopsis thaliana, a small flowering plant.

Pathways that extend lifespan by 500 percent identified

Scientists at the MDI Biological Laboratory, in collaboration with scientists from the Buck Institute for Research on Aging in Novato, Calif., and Nanjing University in China, have identified synergistic cellular pathways for longevity that amplify lifespan fivefold in C. elegans, a nematode worm used as a model in aging research.

The increase in lifespan would be the equivalent of a human living for 400 or 500 years, according to one of the scientists.

The research draws on the discovery of two major pathways governing aging in C. elegans, which is a popular model in aging research because it shares many of its genes with humans and because its short lifespan of only three to four weeks allows scientists to quickly assess the effects of genetic and environmental interventions to extend healthy lifespan.

Biological scientists identify pathways that extend lifespan

Scientists at the MDI Biological Laboratory, in collaboration with scientists from the Buck Institute for Research on Aging in Novato, Calif., and Nanjing University in China, have identified synergistic cellular pathways for longevity that amplify lifespan fivefold in C. elegans, a nematode worm used as a model in aging research.

The increase in would be the equivalent of a human living for 400 or 500 years, according to one of the scientists.

The research draws on the discovery of two major pathways governing aging in C. elegans, which is a popular model in aging research because it shares many of its genes with humans and because its short lifespan of only three to four weeks allows scientists to quickly assess the effects of genetic and environmental interventions to extend healthy lifespan.

Cancer-like metabolism makes brain grow

The size of the human brain increased profoundly during evolution. A certain gene that is only found in humans triggers brain stem cells to form a larger pool of stem cells. As a consequence, more neurons can arise, which paves the way to a bigger brain. This brain size gene is called ARHGAP11B and so far, how it works was completely unknown. Researchers at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden now uncovered its mode of action. They show that the ARHGAP11B protein is located in the powerhouse of the cell—the mitochondria—and induces a metabolic pathway in the brain stem cells that is characteristic of cancer cells.

The research group of Wieland Huttner, a founding director of the Max Planck Institute of Molecular Cell Biology and Genetics, has been investigating the underlying the expansion of the brain during mammalian evolution for many years. In 2015, the group reported a key role for a gene that is only present in humans and in our closest extinct relatives, the Neanderthals and Denisovans. This gene, named ARHGAP11B, causes the so-called basal brain stem to expand in number and to eventually increase the production of neurons, leading to a bigger and more folded brain in the end. How the gene functions within the basal brain stem cells has been unknown so far.

Takashi Namba, a postdoctoral scientist in the research group of Wieland Huttner, wanted to find the answer to this question, together with colleagues from the Max Planck Institute, the University Hospital Carl Gustav Carus Dresden, and the Department of Medical Biochemistry at the Semmelweis University, Budapest. He found that the ARHGAP11B protein is located in mitochondria, the organelles that generate most of the cell’s source of chemical energy and hence are often referred to as the powerhouse of the cell. Takashi Namba explains the results: We found that ARHGAP11B interacts with a protein in the membrane of mitochondria that regulates a membrane pore. As a consequence of this interaction, the pores in the membrane are closing up, preventing calcium leakage from the mitochondria. The resulting higher calcium concentration causes the mitochondria to generate chemical energy by a metabolic pathway called glutaminolysis.

Engrams emerging as the basic unit of memory

Experiments in rodents have revealed that engrams exist as multiscale networks of neurons. An experience becomes stored as a potentially retrievable memory in the brain when excited neurons in a brain region such as the hippocampus or amygdala become recruited into a local ensemble. These ensembles combine with others in other regions, such as the cortex, into an “engram complex.” Crucial to this process of linking engram cells is the ability of neurons to forge new circuit connections, via processes known as “synaptic plasticity” and “dendritic spine formation.” Importantly, experiments show that the memory initially stored across an engram complex can be retrieved by its reactivation but may also persist “silently” even when memories cannot be naturally recalled, for instance in mouse models used to study memory disorders such as early stage Alzheimer’s disease.

“More than 100 years ago Semon put forth a law of engraphy,” wrote Josselyn, Senior Scientist at SickKids, Professor of Psychology and Physiology at the University of Toronto and Senior Fellow in the Brain, Mind & Consciousness Program at the Canadian Institute for Advanced Research, (CIFAR) and Tonegawa, Picower Professor of Biology and Neuroscience at the RIKEN-MIT Laboratory for Neural Circuit Genetics at MIT and Investigator of the Howard Hughes Medical Institute. “Combining these theoretical ideas with the new tools that allow researchers to image and manipulate engrams at the level of cell ensembles facilitated many important insights into memory function.”

“For instance, evidence indicates that both increased intrinsic excitability and synaptic plasticity work hand in hand to form engrams and that these processes may also be important in memory linking, memory retrieval, and memory consolidation.”

For as much as the field has learned, Josselyn and Tonegawa wrote, there are still important unanswered questions and untapped potential applications: How do engrams change over time? How can engrams and memories be studied more directly in humans? And can applying knowledge about biological engrams inspire advances in artificial intelligence, which in turn could feedback new insights into the workings of engrams?

A review in Science traces neuroscientists’ progress in studying the neural substrate for storing memories and raises key future questions for the field.

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