Gravitational biology

Geochronology indicates a rapid transition (tens of Myrs) from primary to secondary crust building on the Moon. The processes responsible for initiating secondary magmatism, however, remain in debate. Here we test the hypothesis that the earliest secondary crust (Mg-suite) formed as a direct consequence of density-driven mantle overturn, and advance 3D mantle convection models to quantify the resulting extent of lower mantle melting. Our modeling demonstrates that overturn of thin ilmenite-bearing cumulates ≤ 100 km triggers a rapid and short-lived episode of lower mantle melting which explains the key volume, geochronological, and spatial characteristics of early secondary crust building without contributions from other energy sources, namely KREEP (potassium, rare earth elements, phosphorus, radiogenic U, Th)...

Einstein's theory of general relativity predicts that a clock at a higher gravitational potential will tick faster than an otherwise identical clock at a lower potential, an effect known as the gravitational redshift. Here we perform a laboratory-based, blinded test of the gravitational redshift using differential clock comparisons within an evenly spaced array of 5 atomic ensembles spanning a height difference of 1 cm. We measure a fractional frequency gradient of [ - 12.4 ± 0...

The vaginal microbiome (VMB) is a complex microbial community that is closely tied to reproductive health. Optimal VMB communities have compositions that are commonly defined by the dominance of certain Lactobacillus spp. and can remain stable over time or transition to non-optimal states dominated by anaerobic bacteria and associated with bacterial vaginosis (BV). The ability to remain stable or undergo transitions suggests a system with either single (mono-stable) or multiple (multi-stable) equilibrium states, though factors that contribute to stability have been difficult to determine due to heterogeneity in microbial growth characteristics and inter-species interactions...

When your head tilts laterally, as in sports, reaching, and resting, your eyes counterrotate less than 20%, and thus eye images rotate, over a total range of about 180°. Yet, the world appears stable and vision remains normal. We discovered a neural strategy for rotational stability in anterior inferotemporal cortex (IT), the final stage of object vision in primates. We measured object orientation tuning of IT neurons in macaque monkeys tilted +25 and -25° laterally, producing ~40° difference in retinal image orientation...

UNLABELLED: Root systems anchor plants to the substrate in addition to transporting water and nutrients, playing a fundamental role in plant survival. The LAZY1 gene mediates gravity signal transduction and participates in root and shoot development and auxin flow in many plants. In this study, a regulator, LsLAZY1, was identified from Leymus secalinus based on previous transcriptome data. The conserved domain and evolutionary relationship were further analyzed comprehensively. The role of LsLAZY1 in root development was investigated by genetic transformation and associated gravity response and phototropism assay...

Space colonization represents the most insidious challenge for mankind, as numerous obstacles affect the success of space missions. Specifically, the absence of gravitational forces leads to systemic physiological alterations, with particular emphasis on the musculoskeletal system. Indeed, astronauts exposed to spaceflight are known to report a significant impairment of bone microarchitecture and muscle mass, conditions clinically defined as osteoporosis and sarcopenia. In this context, space medicine assumes a crucial position, as the development of strategies to prevent and/or counteract weightlessness-induced alterations appears to be necessary...

Throughout the Histoire naturelle Buffon was ever aware of epistemological issues involving the reproduction of species, the only beings in nature. By the 1760s he had come to believe that empirical evidence, the source of all human knowledge, revealed that reproduction was a physical process, involving a common living (minute, active, and lively) matter and material forces, all of which he traced to the foundational force of gravitational attraction.

According to Newton's laws, the weight of a body part is equal to its mass times gravitational acceleration. Our experience of body part weight, however, is constructed by the central nervous system. No sensory receptors directly specify the weight of body parts, and the factors influencing perceived weight remain unknown. The perceived weight of held objects has been linked to sensations of the magnitude of central motor commands sent to the muscles, what Helmholtz called the effort of will and has subsequently been called the sense of effort1 ...

The sinking of gravitationally unstable lithosphere beneath high-elevation plateaus is proposed to be a key driver of their uplift. Numerical geodynamic models predict that lithosphere removal can lead to transient, dynamic topographic changes that could be preserved in the surface record, particularly in sedimentary deposits of lakes or playas that are subsequently inverted. However, few such examples have been documented. Here we show that the Miocene Bidahochi Basin, which was partially and intermittently filled by the Hopi Paleolake, preserves a record of the quasi-elliptical surface response to a viscous drip of lithosphere >100 km beneath the Colorado Plateau...

Gravity is a fundamental interaction that permeates throughout our Universe. On Earth, gravity gives weight to physical objects, and has been a constant presence throughout terrestrial biological evolution. Thus, gravity has shaped all biological functions, some examples include the growth of plants (e.g., gravitropism), the structure and morphology of biological parts in multicellular organisms, to its effects on our physiological function when humans travel into space. Moreover, from an evolutionary perspective, gravity has been a constant force on biology, and life, to our understanding, should have no reason to not experience the effects of gravity...

To study processes related to weightlessness in ground-based cell biological research, a theoretically assumed microgravity environment is typically simulated using a clinostat - a small laboratory device that rotates cell culture vessels with the aim of averaging out the vector of gravitational forces. Here, we report that the rotational movement during fast clinorotation induces complex fluid motions in the cell culture vessel, which can trigger unintended cellular responses. Specifically, we demonstrate that suppression of myotube formation by 2D-clinorotation at 60 rpm is not an effect of the assumed microgravity but instead is a consequence of fluid motion...

Hawking radiation is one of the quantum features of a black hole that can be understood as a quantum tunneling across the event horizon of the black hole, but it is quite difficult to directly observe the Hawking radiation of an astrophysical black hole. Here, we report a fermionic lattice-model-type realization of an analogue black hole by using a chain of 10 superconducting transmon qubits with interactions mediated by 9 transmon-type tunable couplers. The quantum walks of quasi-particle in the curved spacetime reflect the gravitational effect near the black hole, resulting in the behaviour of stimulated Hawking radiation, which is verified by the state tomography measurement of all 7 qubits outside the horizon...

HYPOTHESIS: Droplets of yield stress fluids (YSFs), i.e. fluids that can flow only if they are subjected to a stress above a critical value and otherwise deform like solids, hardly move on solid surfaces due to their high viscosity. The use of highly slippery lubricated surfaces can shed light on the mobility of YSF droplets, which include everyday soft materials, such as toothpaste or mayonnaise, and biological fluids, such as mucus. EXPERIMENTS: The spreading and mobility of droplets of aqueous solutions of swollen Carbopol microgels were studied on lubricant infused surfaces...

Multicellular spheroids are useful models for drug testing or studying tumor biology, but their production requires specialized approaches. Here, we present a protocol to produce viable spheroids by slow rotation around a horizontal axis using standard culture tubes. We describe steps for both seed and starter culture, and maintenance and expansion of spheroids. We detail assessment of spheroid size, count, viability, and immunohistochemistry. This protocol reduces gravitational forces that lead to cell clumping and is amenable to high-throughput use...

Viral vector-based gene therapies and vaccines require accurate characterization of capsid species. The current gold standard for assessing capsid loading of adeno-associated virus (AAV) is sedimentation velocity analytical ultracentrifugation (SV-AUC). However, routine SV-AUC analysis is often size-limited, especially without the use of advanced techniques (e.g., gravitational-sweep) or when acquiring the multiwavelength data needed for assessing the loading fraction of viral vectors, and requires analysis by specialized software packages...

Life on Earth has evolved to thrive in the Earth's natural gravitational field; however, as space technology advances, we must revisit and investigate the effects of unnatural conditions on human health, such as gravitational change. Studies have shown that microgravity has a negative impact on various systemic parts of humans, with the effects being more severe in the human immune system. Increasing costs, limited experimental time, and sample handling issues hampered our understanding of this field. To address the existing knowledge gap and provide confidence in modelling the phenomena, in this review, we highlight experimental works in mechano-immunology under microgravity and different computational modelling approaches that can be used to address the existing problems...

Skeletal muscle is sensitive to gravitational alterations. We recently developed a multiple artificial-gravity research system (MARS), which can generate gravity ranging from microgravity to Earth gravity (1 g) in space. Using the MARS, we studied the effects of three different gravitational levels (microgravity, lunar gravity [1/6 g], and 1 g) on the skeletal muscle mass and myofiber constitution in mice. All mice survived and returned to Earth, and skeletal muscle was collected two days after landing...

Microgravity (μg) is among the major stressors in space causing immune cell dysregulations. These are frequently expressed as increased pro-inflammatory states of monocytes and reduced activation capacities in T cells. Hypergravity (as artificial gravity) has shown to have beneficial effects on the musculoskeletal and cardiovascular system both as a countermeasure option for μg-related deconditioning and as "gravitational therapy" on Earth. Since the impact of hypergravity on immune cells is sparsely explored, we investigated if an application of "mild" mechanical loading of 2...

This review is about Dr. Luiz Rodolpho Raja Gabaglia Travassos' scientific contributions to paracoccidioidomycosis as told by myself, Rosana Puccia, but co-written with Dr. Carlos P. Taborda, my younger scientific brother, collaborator, and dear friend. Dr. Travassos' pioneer papers and scientific insights covering biochemistry, immunology, cell biology, and molecular biology in the paracoccidiodomycosis area are key contributions that we acknowledge here, with focus on the Paracoccidioides antigen gp43. Importantly, we tell some personal stories behind the scene...

Water/ethyl acetate/ethanol is widely used as a "green" extractant system. We show that 2 different types of phase separation can be induced upon centrifugation in this ternary system using ethanol as a cosolvent of water and ethyl acetate: centrifuge-induced criticality and centrifuge-induced emulsification. The expected composition profiles of samples after centrifugation can be represented by bent lines in a ternary phase diagram when gravitational energy is added to the free energy of mixing. The experimental equilibrium composition profiles behave qualitatively as expected and can be predicted using a phenomenological theory of mixing...