The nematode worm Caenorhabditis elegans has produced a wellspring of insights into mechanisms that govern cellular symmetry breaking during animal development. Here we focus on two highly conserved systems that underlie many of the key symmetry-breaking events that occur during embryonic and larval development in the worm. One involves the interplay between Par proteins, Rho GTPases, and the actomyosin cytoskeleton and mediates asymmetric cell divisions that establish the germline. The other uses elements of the Wnt signaling pathway and a highly reiterative mechanism that distinguishes anterior from posterior daughter cell fates. Much of what we know about these systems comes from intensive study of a few key events-Par/Rho/actomyosin-mediated polarization of the zygote in response to a sperm-derived cue and the Wnt-mediated induction of endoderm at the four-cell stage. However, a growing body of work is revealing how C. elegans exploits elements/variants of these systems to accomplish a diversity of symmetry-breaking tasks throughout embryonic and larval development.
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http://dx.doi.org/10.1101/cshperspect.a003400 | DOI Listing |
Nature
January 2025
Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia, Canada.
In a dilute two-dimensional electron gas, Coulomb interactions can stabilize the formation of a Wigner crystal. Although Wigner crystals are topologically trivial, it has been predicted that electrons in a partially filled band can break continuous translational symmetry and time-reversal symmetry spontaneously, resulting in a type of topological electron crystal known as an anomalous Hall crystal. Here we report signatures of a generalized version of the anomalous Hall crystal in twisted bilayer-trilayer graphene, whose formation is driven by the moiré potential.
View Article and Find Full Text PDFPLoS One
January 2025
School of Sport Medicine and Rehabilitation, Beijing Sport University, Beijing, China.
Motor dysfunction and muscle atrophy are typical symptoms of patients with spinal cord injury (SCI). Exercise training is a conventional physical therapy after SCI, but exercise intervention alone may have limited efficacy in reducing secondary injury and promoting nerve regeneration and functional remodeling. Our previous research found that intramedullary pressure after SCI is one of the key factors affecting functional prognosis.
View Article and Find Full Text PDFACS Chem Neurosci
January 2025
Unconventional Computing Laboratory, University of the West of England, Bristol BS16 1QY, U.K.
This study examines the effects of incorporating serotonin (5-HT) into proteinoid microspheres. It looks at the microspheres' structure and electrochemical properties. Proteinoid-serotonin assemblies have better symmetry and membrane organization than pristine proteinoids.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Biozentrum, University of Basel, Spitalstrasse 41, Basel, Basel-Stadt, 4056, SWITZERLAND.
Activity and autonomous motion are fundamental aspects of many living and engineering systems. Here, the scale of biological agents covers a wide range, from nanomotors, cytoskeleton, and cells, to insects, fish, birds, and people. Inspired by biological active systems, various types of autonomous synthetic nano- and micromachines have been designed, which provide the basis for multifunctional, highly responsive, intelligent active materials.
View Article and Find Full Text PDFBMC Plant Biol
January 2025
Jiangxi Provincial Key Laboratory of Subtropical Forest Resources Cultivation, 2011 Collaboration Innovation Center of Jiangxi Typical Trees Cultivation and Utilization, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, China.
Background: Frequent interspecific hybridization, unclear genetic backgrounds, and ambiguous evolutionary relationships within the genus Lycoris pose significant challenges to the identification and classification of hybrids, thereby impacting the application and development of Lycoris. This study utilizes karyotype structure, genome size, and fluorescent in situ hybridization (FISH) technology to explore the chromosomal evolution and hybrid identification of Lycoris employing three approaches at the cytogenetic level.
Results: The findings indicate that species with a smaller basic chromosome number exhibit less asymmetry than those with a larger basic chromosome number, suggesting that species with different basic chromosome numbers may have followed different evolutionary pathways.
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