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Category: biotech/medical – Page 102

Glassed-in DNA makes the ultimate time capsule

Year 2015 face_with_colon_three

IF YOU must preserve messages for people in the far future to read, Blu-ray discs and USB sticks are no good. For real long-term storage, you want a DNA time capsule.

Just 1 gram of DNA is theoretically capable of holding 455 exabytes – enough for all the data held by Google, Facebook and every other major tech company, with room to spare. It’s also incredibly durable: DNA has been extracted and sequenced from 700,000-year-old horse bones. But conditions have to be right for it to last.

A rhythmically pulsing leaf-spring DNA-origami nanoengine that drives a passive follower

DNA nano machine year 2023.

An autonomous DNA-origami nanomachine powered by the chemical energy of DNA-templated RNA-transcription-consuming nucleoside triphosphates as fuel performs rhythmic pulsations is demonstrated. In combination with a passive follower, the nanomachine acts as a mechanical driver with molecular precision.

P-Rex1 limits the agonist-induced internalization of GPCRs independently of its Rac-GEF activity

P-Rex1 activates Rac downstream of GPCRs to regulate processes ranging from innate immunity to neuronal plasticity, its deregulation contributing to cancer. Here, Baker et al. show that P-Rex1 also controls GPCR trafficking, limiting agonist-induced GPCR internalization through an adapter function. Thus, P-Rex1 promotes GPCR responses in a dual manner.

Genetics of Aging and Life Span: Molecular Mechanisms and Intervention Prospects

Abstract The review examines modern advances in the genetics of aging and life span. The key molecular mechanisms regulating aging processes at the genetic level are analyzed, including signaling pathways and longevity genes identified in studies on model organisms and through genome analysis of long-lived species. Special attention is given to the insulin/IGF-1 signaling pathway, the role of the FOXO transcription factor, DNA repair systems, epigenetic regulation, and modulation of mTOR and AMPK kinase activity. Results of experimental studies on increasing the life span of model organisms through genetic manipulations and combined approaches are presented.

Man unexpectedly cured of HIV after stem cell transplant

A man has become the seventh person to be left HIV-free after receiving a stem cell transplant to treat blood cancer. Significantly, he is also the second of the seven who received stem cells that were not actually resistant to the virus, strengthening the case that HIV-resistant cells may not be necessary for an HIV cure.

“Seeing that a cure is possible without this resistance gives us more options for curing HIV,” says Christian Gaebler at the Free University of Berlin.

Image: STEVE GSCHMEISSNER/SCIENCE PHOTO LIBRARY

A handful of people with HIV have been cured after receiving HIV-resistant stem cells – but a man who received non-resistant stem cells is also now HIV-free.

By Carissa Wong

Scientists Discover a Way to ‘Recharge’ Aging Human Cells

New research shows how human cells can be effectively ‘recharged’ by replacing their internal batteries – microscopic power stations called mitochondria – and the discovery could have wide-ranging benefits across healthcare and medical treatments.

The stacks of mitochondria in most of our cells naturally decline in numbers, slow down, and wear out with age. Once they start operating below peak capacity, they can contribute to multiple diseases everywhere from the heart to the brain.

In this latest study, researchers from Texas A&M University used special flower-shaped particles called nanoflowers to scavenge damaging oxygen molecules, triggering genes that increase the number of mitochondria in human stem cells.

Epigenetic changes regulate gene expression, but what regulates epigenetics?

A chromosome pulled from the flowers of Arabidopsis thaliana (green and white) unspools to reveal DNA (blue) coiled around packaging-proteins called histones (purple). The direction of epigenetic changes by genetic features begins as the RIM transcription factor (pink) docks on a corresponding DNA sequence (pink). Once docked, the RIM transcription factor directs methylation machinery to tack methyl groups (orange) onto specific nearby cytosines (orange). Click here for a high-resolution image. Credit: Salk Institute.

All the cells in an organism have the exact same genetic sequence. What differs across cell types is their epigenetics—meticulously placed chemical tags that influence which genes are expressed in each cell. Mistakes or failures in epigenetic regulation can lead to severe developmental defects in plants and animals alike. This creates a puzzling question: If epigenetic changes regulate our genetics, what is regulating them?

Scientists at the Salk Institute have now used plant cells to discover that a type of epigenetic tag, called DNA methylation, can be regulated by genetic mechanisms. This new mode of plant DNA methylation targeting uses specific DNA sequences to tell the methylation machinery where to dock. Prior to this study, scientists had understood only how DNA methylation was regulated by other epigenetic features, so the discovery that genetic features can also guide DNA methylation patterns is a major paradigm shift.

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