Science Society

In this episode, we're delighted to welcome Abbigail Elms, who has been studying some of the coolest white dwarf stars known to date. Abbigail shares insights into two fascinating celestial bodies, WD J2147−4035 and WD J1922+0233, which are ultra-cool, metal-polluted (DZ) white dwarfs with surprisingly low temperatures. We discuss the intriguing features of these stars, including their unusually blue or red colours, as well as the innovative microphysics techniques Abbigail and her team use to understand them. Abbigail also reveals the extreme age of these white dwarfs - with WD J2147−4035 reaching over 10 billion years - and how they offer valuable information about the age of the Galactic disc in the Milky Way. Tune in to learn about these pivotal celestial objects and their potential impact on our understanding of the universe.

Ultra-cool white dwarfs, metal-polluted, WD J2147−4035, WD J1922+0233, microphysics, model atmosphere code, collision-induced absorption, Galactic kinematics, Gaia EDR3 astrometry, Galactic disc, spectroscopy, sodium, potassium, calcium, lithium, Zeeman splitting, accreted planetary crust debris, Milky Way.

Abbigail K Elms Spectral analysis of ultra-cool white dwarfs polluted by planetary debris, https://doi.org/10.1093/mnras/stac2908

In this episode, we delve into the intricate world of animal memory and decision-making with our esteemed guest, Dr. Clint Sergi. He sheds light on his fascinating research involving the memory capacity of the West black widow spider. Through an innovative experiment, Dr. Sergi and his team triggered search behaviors in these spiders by removing their prey from different areas of their webs, effectively 'stealing' it. This allowed them to infer what information the spiders retained about their prey - such as relative size and location of capture within the web. Join us as we explore this interesting study and the broader implications it has for our understanding of animal ecology, evolution, and memory formation.

Key Words: Animal memories, adaptive decision-making, black widow spiders, searching behavior, prey theft, search effort, the memory of prey, prey size, prey capture location, gum-footed lines, behavioral observations, animal ecology, animal evolution, memory formation.

Black widow spiders (Latrodectus hesperus) remember prey capture location and size but only alter behavior for prey caught at particular sites Clint Sergi, et al. https://doi.org/10.1111/eth.13328

This episode takes us on a journey into the vast world of Earth's microbial life with our distinguished guest, Dr. Averill. Microbes, particularly soil fungi, play an instrumental role in driving essential processes across diverse ecosystems - from our own bodies to vast forests. However, the biodiversity of these microscopic powerhouses is increasingly under threat. Dr. Averill's groundbreaking work advocates for the conservation, restoration, and active incorporation of soil microbes into managed landscapes. By analyzing data from 80 experiments, his team showed that restoring native soil microbiomes could accelerate plant biomass production by an average of 64% across ecosystems. Such restoration not only boosts and stabilizes yields in agriculture and forestry but also plays a critical role in preserving microbial biodiversity. As we navigate the emerging markets of ecosystem microbiome engineering, it's crucial to avoid past mistakes and prevent the creation of microbial monocultures. Join us as we delve into this exciting field of research, which holds the potential to revolutionize ecosystem management and conservation.

Key Words: Microbial life, biodiversity, microbiome, conservation, restoration, soil fungi, plant biomass, ecosystem management, agriculture, forestry, microbial biodiversity, ecosystem vulnerability, pathogens, extreme events, microbial monocultures, ecosystem microbiome engineering.

Averill, C., Anthony, M.A., Baldrian, P. et al. Defending Earth’s terrestrial microbiome. Nat Microbiol (2022). https://doi.org/10.1038/s41564-022-01228-3

Join us in this fascinating episode with Dr. Hawn as we delve into the realm of psychopathology, biological aging, and mortality. Psychopathology is often linked to faster biological aging and premature death. Dr. Hawn and her team's pioneering research have sought to better understand these relationships. They have examined associations between broad dimensions of psychopathology, post-traumatic stress disorder (PTSD), and GrimAge, a DNA methylation biomarker indicative of mortality risk relative to age. The research has also focused on understanding the neurobiological correlates of GrimAge, including neurocognitive functioning, inflammation, neuropathology, metabolic disease, and cortical thickness. Their findings show that externalizing psychopathology significantly predicts GrimAge, while PTSD appears to be linked to GrimAge in younger but not older cohorts. Also, GrimAge is associated with a variety of neurobiological variables, including cognitive disinhibition, memory recall, cardiometabolic pathology, oxidative stress, astrocyte damage, inflammation, and immune function. Tune in as we unpack these intriguing findings, and how they might aid in early disease identification and treatment.

Key Words: Psychopathology, biological aging, mortality risk, GrimAge, PTSD, neurobiological correlates, neurocognitive functioning, inflammation, neuropathology, metabolic disease, cortical thickness, cardiometabolic pathology, oxidative stress, astrocyte damage, immune functioning, emotion regulation, facial recognition, disease identification, disease treatment.

Hawn, et al. For whom the bell tolls: psychopathological and neurobiological correlates of a DNA methylation index of time-to-death. Transl Psychiatry(2022). https://doi.org/10.1038/s41398-022-02164-w

In this enlightening episode, we sit down with Dr. Longo to explore the intriguing role of fasting-mimicking diet (FMD) cycles in reducing Alzheimer's Disease (AD) symptoms and cognitive decline. The FMD cycles have demonstrated considerable potential in decreasing various aging and disease risk factors. As discussed by Dr. Longo, recent studies reveal that these diet cycles can reduce cognitive decline and AD pathology in mouse models more effectively than protein restriction cycles. Furthermore, long-term FMD cycles have demonstrated significant potential in reducing hippocampal Aβ load and hyperphosphorylated tau, enhancing neural stem cell genesis, decreasing the number of microglia, and reducing the expression of neuroinflammatory genes, including NADPH oxidase (Nox2). The deletion of Nox2 in mice or treatment with an NADPH oxidase inhibitor also leads to improved cognition and reduced microglia activation. Preliminary clinical data suggest the feasibility and general safety of FMD cycles in a small group of AD patients. Join us as Dr. Longo takes us through these fascinating findings that indicate FMD cycles' potential to delay cognitive decline in AD models by reducing neuroinflammation and superoxide production in the brain.

Key Words: Fasting-Mimicking Diet (FMD), Alzheimer's Disease, Cognitive Decline, Aging, Disease Risk Factors, Protein Restriction, Neuroinflammation, Superoxide Production, NADPH Oxidase, Neural Stem Cells, Microglia, Aβ Load, Hyperphosphorylated Tau.

Fasting-mimicking diet cycles reduce neuroinflammation to attenuate cognitive decline in Alzheimer’s models https://doi.org/10.1016/j.celrep.2022.111417

Join us in this episode as we engage with Dr. Budson in discussing the evolution and complex roles of consciousness and memory. There is often a mix-up between why consciousness developed and the additional roles it has adopted over continued evolution. Dr. Budson proposes that consciousness originally evolved as part of the episodic memory system, likely to enable the flexible combination and rearrangement of past events to plan for the future. Over time, consciousness has been co-opted to fulfill other non-memory-related functions such as problem-solving, abstract thinking, and language. This theory, Dr. Budson argues, aligns with several phenomena, like the slow speed and the retrospective nature of consciousness, that other theories struggle to explain. Understanding this could have profound implications for our comprehension of intentional action and consciousness in general. Furthermore, Dr. Budson suggests that the systems of episodic, sensory, working, and semantic memory should collectively be viewed as the conscious memory system since they jointly contribute to the phenomenon of consciousness. He also contends that every cortical region of the brain contributes to this conscious memory system. Tune in as we dissect these intriguing perspectives and their potential impact on our understanding of consciousness.

Key Words: Consciousness, memory, episodic memory, evolution, flexible recombination of information, problem-solving, abstract thinking, language, intentional action, sensory memory, working memory, semantic memory, conscious memory system, cerebral cortex.

Consciousness as a Memory System Budson, Andrew E. MD*, Richman, Kenneth A. PhD; Kensinger, Elizabeth A. PhD Cognitive and Behavioral Neurology: doi: 10.1097/WNN.0000000000000319

In this insightful episode, we delve into the complex realm of epigenetics with Dr. Kaneshiro, exploring how parental epigenomes can significantly influence offspring development and health. Utilizing the model organism, Caenorhabditis elegans, Dr. Kaneshiro elaborates on the role of sperm-inherited histone marking in shaping offspring gene expression. Remarkably, the absence of the repressive mark H3K27me3 from the sperm genome leads to up-regulation from sperm alleles in offspring somatic and germline tissues. The research reveals that tissue context determines which genes are prone to up-regulation. Intriguingly, the findings mirror those in mammalian cells, suggesting a conserved mechanism for chromatin-based regulation. Furthermore, Dr. Kaneshiro reveals that the sperm-inherited pattern of gene marking and gene up-regulation are transmitted to grandoffspring, indicating that H3K27me3 marking can act as a bona fide transgenerational epigenetic carrier in C. elegans. Join us for this fascinating journey into the world of transgenerational epigenetics.

Key Words: Epigenetics, Offspring Development, Parental Epigenomes, Caenorhabditis Elegans, Sperm-Inherited Histone Marking, Gene Expression, H3K27me3, Somatic Tissues, Germline Tissues, Transgenerational Epigenetic Carrier, Up-regulation, Chromatin-Based Regulation.

Sperm-inherited H3K27me3 epialleles are transmitted transgenerationally in cis

https://doi.org/10.1073/pnas.2209471119

Dr. Sudimac joins us in this episode to unravel the intriguing relationship between urban living, natural environments, and mental health. As city living is often associated with an increased risk for mental disorders such as anxiety, depression, and schizophrenia, understanding how exposure to different environments influences mental health is crucial. Dr. Sudimac presents an intervention study exploring the changes in stress-related brain regions resulting from a one-hour walk in an urban or natural environment. Interestingly, amygdala activation, known to be associated with stress, decreases after a walk in nature but remains stable after an urban walk. This suggests that nature walks can have salutogenic effects on stress-related brain regions, potentially acting as a preventive measure against mental strain and disease. As we navigate the rapid urbanization of our world, this knowledge may significantly impact urban planning, emphasizing the creation of more accessible green spaces to support the mental well-being of citizens.

Key Words: Mental Health, Urban Environments, Natural Environments, Anxiety, Depression, Schizophrenia, Amygdala Activation, Stress-Related Brain Regions, Intervention Study, Salutogenic Effects, Urban Planning, Green Spaces.

Sudimac, S., Sale, V. & Kühn, S. How nature nurtures: Amygdala activity decreases as the result of a one-hour walk in nature. Mol Psychiatry (2022). https://doi.org/10.1038/s41380-022-01720-6

In this captivating episode, Dr. Tarduno delves into the mysteries of Earth's inner core, its structure, and how it began to crystallize. Through the lens of paleomagnetism, we explore the evolution of Earth's magnetic field, deciphering changes in its strength and understanding how these shifts provide clues about the core's history. Dr. Tarduno presents intriguing findings from single crystal paleointensity studies of early Cambrian anorthosites, which reveal a rapid resurgence of the magnetic field following a period of ultralow field strength in the Ediacaran Era. This dramatic shift pinpoints the inner core nucleation to around 550 million years ago. Further thermal modeling based on this age suggests the inner core had grown to half its present size by approximately 450 million years ago. Delving deeper, we discuss how seismic anisotropy within the inner core might reflect the development of global deep mantle structures, leaving an indelible imprint on our planet. Join us as we journey to the center of the Earth and back.

Key Words: Inner Core, Paleomagnetism, Earth's Magnetic Field, Core Crystallization, Anorthosites, Inner Core Nucleation, Thermal Modeling, Seismic Anisotropy, Deep Mantle Structure, Earth's Geodynamo, Ediacaran Period, Cambrian Period.

Zhou, T., Tarduno, J.A., Nimmo, F. et al. Early Cambrian renewal of the geodynamo and the origin of inner core structure. Nat Commun 13, 4161 (2022). https://doi.org/10.1038/s41467-022-31677-7

Delve into the intriguing world of prebiotic chemistry with Dr. Krishnamurthy as we explore the origins of α-amino acids and the evolutionary shift from the Strecker reaction to modern biological pathways. We discuss how α-ketoacids, through the Bucherer–Bergs pathway, react with cyanide and ammonia to form corresponding α-amino acids, highlighting the prebiotic transformation of oxaloacetate to aspartate. This transformation enables the formation of dihydroorotate, mirroring the biochemical synthesis of orotate—a precursor to pyrimidine nucleobases. We also examine how glyoxylate forms both glycine and orotate and reacts with malonate and urea to produce aspartate and dihydroorotate. Our conversation extends to the previously demonstrated protometabolic analogues of the Krebs cycle, underscoring the possibility of a natural emergence of biological pathways from prebiotic chemistry. This insightful discussion with Dr. Krishnamurthy illuminates the seamless transition from the primordial world of chemistry to the complexity of contemporary metabolism.

Key Words: Prebiotic Chemistry, α-Amino Acids, Strecker Reaction, Bucherer–Bergs Pathway, α-Ketoacids, Oxaloacetate, Aspartate, Dihydroorotate, Orotate, Pyrimidine Nucleobases, Glyoxylate, Glycine, Malonate, Urea, Protometabolic Analogues, Krebs Cycle, Metabolic Evolution.

Pulletikurti et al. Prebiotic synthesis of α-amino acids and orotate from α-ketoacids potentiates transition to extant metabolic pathways. Nat. Chem. (2022). https://doi.org/10.1038/s41557-022-00999-w