Science Society

In this episode, Dr. Cagan joins us to discuss his intriguing research on the rates and patterns of somatic mutation across a variety of mammalian species. Somatic mutation, the process of change in the DNA of an organism's cells other than sperm or egg cells, plays a key role in cancer and aging. However, the specifics of this process in non-human species have remained largely unknown.

Dr. Cagan and his team have shed light on the landscape of somatic mutation by conducting whole-genome sequencing of 208 intestinal crypts from 56 individuals across 16 mammalian species. They found that mutation is dominated by endogenous processes in all species, such as 5-methylcytosine deamination and oxidative damage. Interestingly, mutational signatures across species closely resemble those found in humans, though the contributions of each signature vary.

A key finding from Dr. Cagan's work is that the somatic mutation rate per year inversely correlates with species lifespan, suggesting an evolutionary constraint on somatic mutation rates. Despite the enormous variation in lifespan and body mass among the studied species, the somatic mutation burden at the end of lifespan only varied by a factor of around 3.

Join us as we delve into this fascinating research with Dr. Cagan, exploring the implications of these findings for our understanding of aging and evolution.

Keywords: Dr. Cagan, Somatic Mutation, Mammalian Species, Whole-Genome Sequencing, Aging, Cancer, Evolution, Lifespan.

https://doi.org/10.1038/s41586-022-04618-z Somatic mutation rates scale with lifespan across mammals

In this enlightening episode, we're joined by Dr. Qi Hu to discuss his impactful research on climate variation in Central Asia. Given that over 60% of Central Asia experiences arid to semi-arid climates, changes in the region's climate patterns can have profound impacts on food production, natural resource availability, and overall societal stability.

Through an innovative approach using climate classification, Dr. Hu and his team have been able to identify specific geographical patterns of climate variation. Since the 1980s, the desert climate in the region has expanded northward by over 100 km, and temperatures have increased across all climate types.

Perhaps most significant are the changes observed in the region's mountainous areas, where previously cold climates have been replaced by warmer, wetter conditions. These shifts are not only leading to the fast retreat of glaciers and a rise in groundwater levels but also have the potential to reshape the region's hydrology and ecology.

As we delve into the complexities of this research with Dr. Hu, we'll explore the implications of these findings for both Central Asia's environment and its societies and how these changes could impact future agricultural practices, economic stability, and ecological systems.

Keywords: Dr. Qi Hu, Climate Variation, Central Asia, Climate Classification, Desert Expansion, Increased Temperatures, Hydrology, Ecosystems, Agriculture, Societal Stability.

Northward Expansion of Desert Climate in Central Asia in Recent Decades Qi Hu,Zihang Han https://doi.org/10.1029/2022GL098895

This episode features a fascinating discussion with Dr. Ryan Chiechi about his groundbreaking research in the field of molecular electronics. His team has achieved a significant milestone in creating digital logic circuits from protein complexes and liquid metal electrodes. This achievement paves the way for a whole new understanding and approach toward electronics at the molecular level.

Dr. Chiechi's protein-based resistors and diodes showcase a unique feature - temperature-independent charge transport across approximately 10 nm distances. Moreover, these circuits don't require special handling or encapsulation, which significantly simplifies their usage.

A key characteristic of these protein complexes is that their function is entirely dependent on self-assembly. The orientation of the dipole moments within these assemblies determines their electrical conductivity, adding dynamic functionality to these protein-based circuits.

Dr. Chiechi further demonstrates the practical applications of these molecular electronic devices by creating pulse modulators based on AND and OR logic gates. These innovative circuits perform almost identically to their simulated counterparts, indicating a significant step forward in the field of molecular electronics.

Join us as we dive into the details of this intriguing research and explore the future possibilities that molecular electronics hold.

Keywords: Dr. Ryan Chiechi, Digital Logic Circuits, Protein Complexes, Liquid Metal Electrodes, Molecular Electronics, Self-assembly, Dipole Moments, AND and OR Logic Gates, Molecular Self-assembly.

https://doi.org/10.1038/s41467-022-30038-8 The fabrication of digital logic circuits comprising resistors and diodes made from protein complexes wired together using printed liquid metal electrodes.

Join us in this fascinating episode where we converse with Dr. Thomas Armbruster on his innovative research in neurobiology. The episode dives deep into the intricacies of astrocyte-neuron interactions and the unique role that astrocytes play in neuronal activity.

Astrocytes, a type of glial cell, are known to interact with neuronal synapses through their distal processes, aiding in the removal of glutamate and potassium (K+) post-neuronal activity. These actions are dependent on astrocyte membrane potential (Vm). Interestingly, while astrocyte Vm has long been considered largely static, Dr. Armbruster’s research paints a different picture.

By utilizing genetically encoded voltage indicators, Dr. Armbruster's team measured Vm at peripheral astrocyte processes (PAPs) in mice. They discovered large, quick, focal, and pathway-specific depolarizations in PAPs during neuronal activity. These depolarizations, driven by presynaptic K+ efflux and electrogenic glutamate transporters in response to neuronal activity, inhibited astrocyte glutamate clearance.

This finding unveils a new dimension of astrocyte-neuron interaction, with astrocyte depolarization enhancing neuronal activation by glutamate. Such an intricate form of astrocyte-neuron interaction represents a novel class of subcellular astrocyte membrane dynamics, opening up fresh avenues in our understanding of neurobiology.

Join us as we discuss these intriguing findings and their implications for the future of neuroscience.

Keywords: Dr. Thomas Armbruster, Astrocytes, Neurons, Glutamate Clearance, Membrane Potential, Neurobiology, Peripheral Astrocyte Processes, Depolarization, Glial Cells, Neuronal Activation.

https://doi.org/10.1038/s41593-022-01049-x Neuronal activity drives pathway-specific depolarization of peripheral astrocyte processes

In this episode, we delve into the fascinating world of auditory neuroscience with Dr. Elena Dellaferrera. We explore how our auditory system separates individual sources from mixed sounds - a challenge known as blind source decomposition.

In nature, auditory signals usually originate from multiple sound sources occurring simultaneously. Recognizing these individual sources is a formidable task for the human auditory system, which it handles elegantly by identifying repeating patterns within the acoustic input. However, recreating this behavior through computational models has been a largely unexplored territory.

Dr. Dellaferrera introduces us to her innovative, biologically inspired computational model designed to perform blind source separation on mixed acoustic stimuli sequences. The proposed model, grounded in a somatodendritic neuron model and a Hebbian-like learning rule, was designed to detect recurring spatio-temporal patterns in synaptic inputs.

This computational model effectively segregates sources, echoing the characteristics of human performance across different experimental settings using synthesized sounds with naturalistic properties. Dr. Dellaferrera's work further extends this study to unexplored territories, including natural sounds and images.

Join us as we delve into the implications of this exciting research, its potential to enrich our understanding of auditory neuroscience, and how it can inform predictions in yet-to-be-tested experimental settings.

Keywords: Dr. Elena Dellaferrera, Blind Source Decomposition, Auditory Neuroscience, Computational Models, Sound Source Separation, Somatodendritic Neuron Model, Hebbian Learning Rule, Segregation Capabilities.

Modeling the Repetition-Based Recovering of Acoustic and Visual Sources With Dendritic Neurons https://doi.org/10.3389/fnins.2022.855753

Join us for this summary episode, where we dive into the highlights from our recent guest speaker series. Each week, we had the privilege of hosting exceptional thought leaders and researchers from diverse fields, who shared their pioneering research, intriguing discoveries, and insightful perspectives.

Our lineup featured some of the greatest minds in fields spanning from neuroscience and genomics to environmental science and artificial intelligence. These discussions touched on everything from the intricacies of brain development and the mysteries of the human genome to groundbreaking solutions for environmental challenges and innovative advancements in AI technology.

In this episode, we'll revisit the key takeaways from each speaker, reflect on the questions posed by our audience, and look at how these discussions contribute to our understanding of these complex topics. We will also provide a sneak peek into our upcoming lineup of guest speakers.

This is a fantastic opportunity to catch up on any discussions you may have missed, refresh your memory on those you attended, and gain an overview of the diverse topics we've explored so far in our series. Don't miss out on this comprehensive review of our enriching conversations with these trailblazing guests!

Keywords: guest speaker series, neuroscience, genomics, environmental science, artificial intelligence, recap, summary, research, discovery, advancements.

In this insightful episode, we venture into the universe's depths with Dr. Sedat Ata, exploring the complex structure and evolution of our cosmos. We discuss the vital role of cosmological simulations in studying the universe and how these simulations can align with real observed structures.

Dr. Ata introduces us to a novel approach in cosmic exploration - constrained cosmological simulations. These are specifically designed to match the observed distribution of galaxies, enabling scientists to 'fast-forward' the simulation to our present day and study the evolution of cosmic structures in a self-consistent way.

Based on spectroscopic surveys at a redshift of z ≈ 2.3, approximately 11 Gyr ago, these simulations predict that several protoclusters observed earlier would evolve into massive galaxy clusters today. One such prediction includes the 'Hyperion' structure, which will collapse into a filamentary supercluster spanning 100 Mpc.

Moreover, the constrained simulations reveal previously unknown protoclusters with lower final masses, nearly doubling the number of known protoclusters within this volume. The approach Dr. Ata presents, when applied to future high-redshift datasets, offers a unique opportunity to study early structure formation and match galaxy properties between high and low redshifts.

Tune in as we journey through time and space, understanding the universe's past, present, and future, and learn about the fascinating structures it houses.

Keywords: Dr. Sedat Ata, Cosmological Simulations, Constrained Cosmological Simulations, Universe Structure, Protoclusters, Superclusters, Galaxy Clusters, High-redshift Datasets.

Ata, M., Lee, KG., Vecchia, C.D. et al. Predicted future fate of COSMOS galaxy protoclusters over 11 Gyr with constrained simulations. Nat Astron (2022). https://doi.org/10.1038/s41550-022-01693-0

Aging, a complex process marked by gradual declines in fitness and function, remains a key area of scientific inquiry. Dr. Raj Gill joins us in this episode to shed light on how the aging process impacts cells, leading to reduced function, altered gene expression, and a disrupted epigenome.

Dr. Gill introduces us to an innovative technique known as "Maturation Phase Transient Reprogramming" (MPTR), designed to rejuvenate the epigenome without fully reprogramming cells. This novel method, applied to dermal fibroblasts from middle-aged donors, demonstrates the exciting potential for substantially rejuvenating multiple cellular attributes.

The MPTR method provides a way for cells to temporarily lose their identity and then reacquire it, suggesting an intriguing interplay of epigenetic memory and persistent gene expression. The transcriptome, the epigenome, and H3K9me3 levels were all significantly rejuvenated. Moreover, the fibroblasts rejuvenated through MPTR were observed to produce youthful levels of collagen proteins and demonstrate enhanced migration speed, indicating functional rejuvenation.

In this stimulating conversation, Dr. Gill also hints at the existence of optimal time windows for rejuvenating the transcriptome and the epigenome, thereby setting the stage for further exploration in this area.

Tune in as we delve into the exciting world of cellular aging, and learn how it might be possible to turn back time at the cellular level to discover new anti-aging genes and therapies.

Keywords: Dr. Raj Gill, Aging, Epigenome, Transcriptome, Maturation Phase Transient Reprogramming (MPTR), Cellular Rejuvenation, Dermal Fibroblasts, Anti-aging Therapy.

https://doi.org/10.7554/eLife.71624 Multi-omic rejuvenation of human cells by maturation phase transient reprogramming

In this captivating episode, we're joined by Dr. Autti, a leading physicist who takes us into the mesmerizing world of time crystals - macroscopic quantum systems in periodic motion in their ground state.

The groundbreaking experiments by Dr. Autti and his team provide an in-depth look at two coupled time crystals made of spin-wave quasiparticles, known as magnons. These form a macroscopic two-level system with a fascinating twist: the two levels evolve over time based on an intrinsic nonlinear feedback, creating a form of spontaneous two-level dynamics.

Dr. Autti elucidates the process of a level crossing in these systems, where magnons move from the ground level to the excited level due to the Landau-Zener effect and Rabi population oscillations. This exploration of magnon time crystals reveals a way to access every detail of quantum-coherent interactions in a single experiment.

We also discuss the potential applications and implications of this research. Not only does this study open avenues for the detection of surface-bound Majorana fermions in the underlying superfluid system, but it also prompts the possibility of harnessing coherent magnon phenomena in technological applications - potentially even at room temperature.

Join us as we traverse the fascinating terrains of quantum physics, exploring the concept of time crystals, and uncover the potential they hold in the world of quantum technology.

Keywords: Dr. Autti, Time Crystals, Quantum Systems, Magnons, Quantum Coherent Interactions, Nonlinear Feedback, Landau-Zener Effect, Rabi Population Oscillations, Majorana Fermions, Superfluid Systems.

Autti, S., Heikkinen, P.J., Nissinen, J. et al. Nonlinear two-level dynamics of quantum time crystals. Nat Commun 13, 3090 (2022). https://doi.org/10.1038/s41467-022-30783-w

In this enlightening episode, we welcome Dr. Andrés Cubillos-Ruiz, who takes us into the world of gut health and antibiotics. His pioneering research proposes a compelling solution to antibiotic-induced alterations in the gut microbiota—a problem that contributes to various metabolic and inflammatory diseases, increases the risk of secondary infections, and fuels the emergence of antimicrobial resistance.

Dr. Cubillos-Ruiz introduces us to an engineered strain of Lactococcus lactis that selflessly degrades β-lactams—a widely used class of broad-spectrum antibiotics that disrupt gut flora—through the secretion and extracellular assembly of a heterodimeric β-lactamase. He explains the unique design of this β-lactamase-expression system, which neither confers β-lactam resistance to the producer cell nor is susceptible to dissemination by horizontal gene transfer.

The intriguing part is how this research plays out in vivo. In a mouse model treated with parenteral ampicillin, oral supplementation with this engineered live biotherapeutic minimized gut dysbiosis without affecting the ampicillin concentration in serum. It also prevented the enrichment of antimicrobial resistance genes in the gut microbiome and the loss of colonization resistance against Clostridioides difficile.

Join us as we delve into the potential of engineered live biotherapeutics that safely degrade antibiotics in the gut, a strategy that could revolutionize the prevention of dysbiosis and associated pathologies.

Keywords: Dr. Andrés Cubillos-Ruiz, Gut Microbiota, Antibiotics, β-lactams, Lactococcus lactis, β-lactamase, Dysbiosis, Antimicrobial Resistance, Biotherapeutics, Metabolic Diseases, Inflammatory Diseases.

https://doi.org/10.1038/s41551-022-00871-9 An engineered live biotherapeutic protects the intestinal microbiome.