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The shell of the cephalopod consists of two layers of fibers that elongate perpendicular to the shell surfaces. Fibers have a high-Mg calcitic core sheathed by thin organic membranes (>100 nm) and configurate a polygonal network in cross section. Their evolution has been studied by serial sectioning with electron microscopy-associated techniques. During growth, fibers with small cross-sectional areas shrink, whereas those with large sections widen. It is proposed that fibers evolve as an emulsion between the fluid precursors of both the mineral and organic phases. When polygons reach big cross-sectional areas, they become subdivided by new membranes. To explain both the continuation of the pattern and the subdivision process, the living cells from the mineralizing tissue must perform contact recognition of the previously formed pattern and subsequent secretion at sub-micron scale. Accordingly, the fabrication of the argonaut shell proceeds by physical self-organization together with direct cellular activity.
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http://dx.doi.org/10.1016/j.isci.2021.103288 | DOI Listing |
Sci Rep
August 2025
Institute of Technical Physics and Materials Science, HUN-REN Centre for Energy Research, P.O. Box 49, 1525, Budapest, Hungary.
The exploration of brain networks has reached an important milestone as relatively large and reliable information has been gathered for connectomes of different species. Analyses of connectome data sets reveal that the structural length follows the exponential rule, the distributions of in- and out-node strengths follow heavy-tailed lognormal statistics, while the functional network properties exhibit powerlaw tails, suggesting that the brain operates close to a critical point where computational capabilities and sensitivity to stimulus is optimal. Because these universal network features emerge from bottom-up (self-)organization, one can pose the question of whether they can be modeled via a common framework, particularly through the lens of criticality of statistical physical systems.
View Article and Find Full Text PDFNat Phys
July 2025
Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA.
Many bacteria inhabit thin water layers on solid surfaces. These thin films occur both naturally - in soils, on hosts, on textiles - and in the lab on agar hydrogels. In these environments, cells the water menisci formed around bacteria lead to capillary attraction between cells while still allowing them to slide past one another.
View Article and Find Full Text PDFFront Neurosci
August 2025
Department of Physics, Missouri University of Science and Technology, Rolla, MO, United States.
Serotonergic axons (fibers) are a universal feature of all vertebrate brains. They form meshworks, typically quantified with regional density measurements, and appear to support neuroplasticity. The self-organization of this system remains poorly understood, partly because of the strong stochasticity of individual fiber trajectories.
View Article and Find Full Text PDFAnnu Rev Cell Dev Biol
August 2025
Laboratory of Experimental Ontogeny, Institute of Biomedical Sciences and Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; email:
The primordial body architecture of vertebrates is established during gastrulation, a critical period of development characterized by the emergence of the three germ layers (ectoderm, mesoderm, and endoderm) and the formation of an embryo with clearly identifiable dorso-ventral and anterior-posterior axes. In zebrafish, gastrulation involves molecular and cellular mechanisms that are broadly conserved among vertebrates, with species-specific features imposed by the deterministic role of maternally deposited determinants, the architecture of extraembryonic structures that create a dynamic and physically constrained environment, and the mesenchymal nature of early cells that underpins the migratory nature of mesendoderm internalization. Significant progress has been made in the genetic networks, signaling pathways, and cell dynamics involved, and the unique features of the zebrafish embryo are helping to elucidate the intricate coordination between gene expression, mechanical forces, self-organization, and morphogenetic movements that shape the early embryo.
View Article and Find Full Text PDFCurr Biol
August 2025
School of Natural Sciences, Macquarie University, Sydney, NSW 2109, Australia. Electronic address:
Teamwork is often assumed to enhance group performance, particularly for physical tasks. However, in both human and non-human animal teams, the effort contributed by each member may, in fact, decrease as team size grows. This counterintuitive phenomenon, known as the Ringelmann effect, is generally ascribed to poor coordination or differences in motivation.
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