Cellular functions such as cell division are remarkably conserved across phyla. However, the evolutionary principles of cellular organization that drive them are less well explored. Thus, an essential question remains: to what extent do cellular parameters evolve without altering the basic functions they sustain? Here we have observed six different nematode species for which the mitotic spindle is positioned asymmetrically during the first embryonic division. Whereas the spindle undergoes oscillations during its displacement, the spindle elongates without oscillations in other species. We asked which evolutionary changes in biophysical parameters could explain differences in spindle motion while maintaining a constant output. Using laser microsurgery of the spindle, we revealed that all species are subjected to cortical pulling forces of varying magnitudes. Using a viscoelastic model to fit the recoil trajectories and with an independent measurement of cytoplasmic viscosity, we extracted the values of cytoplasmic drag, cortical pulling forces, and spindle elasticity for all species. We found large variations in cytoplasmic viscosity, whereas cortical pulling forces and elasticity were often more constrained. In agreement with previous simulations, we found that increased viscosity correlates with decreased oscillation speeds across species. However, the absence of oscillations in some species despite low viscosity can only be explained by smaller pulling forces. Consequently, we find that spindle mobility across the species analyzed here is characterized by a tradeoff between cytoplasmic viscosity and pulling forces normalized by the size of the embryo. Our work provides a framework for understanding mechanical constraints on evolutionary diversification of spindle mobility.
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http://dx.doi.org/10.1091/mbc.E21-10-0532 | DOI Listing |
J Tradit Complement Med
January 2025
Chinese Medicine Research Center, China Medical University, Taichung, Taiwan.
The sensation of sng (pronounced/səŋ/, the Romanization form of or soreness in Taiwanese Southern Min) associated with a composite of unique sensations, is a novel phenotype for acupoint stimulation. It is perceived by test participants but also by experienced practitioners as a sensation of "taking the bait" (by fish when fishing), a characteristic heavy and tight sensation from the needle. Here, we propose that sng is a powerful biomarker for associated with successful manual acupuncture.
View Article and Find Full Text PDFJ Thromb Haemost
January 2025
Department of Pathology and Laboratory Medicine; Institute of Reproductive Medicine and Developmental Sciences, The University of Kansas Medical Center, Kansas City, KS 66160. Electronic address:
Background: A loss-of-functional mutation (W1183R) in human complement factor H (CFH) is associated with complement-associated hemolytic uremic syndrome; mice carrying a similar mutation (W1206R) in CFH also develop thrombotic microangiopathy but its plasma von Willebrand factor (VWF) multimer sizes were dramatically reduced. The mechanism underlying such a dramatic change in plasma VWF multimer distribution in these mice is not fully understood.
Objective And Methods: To determine the VWF and CFH interaction and how CFH proteins affect VWF multimer distribution, we employed recombinant protein expression, purification, and various biochemical and biophysical tools.
J Am Vet Med Assoc
January 2025
Objective: To explain design features of scissors and surgical instruments that work against left-handed users and demonstrate how the user can adapt their technique for ambidextrous use of standard instruments.
Animals: Any species.
Methods: Standard instruments are designed for maximal efficiency with the use of a right-handed grip.
Front Bioeng Biotechnol
December 2024
Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China.
Purpose: Spine is the most commonly found fracture site due to osteoporosis. Combined exercise including high-impact and resistance exercise shows the potential to improve bone mineral density (BMD) in the spine. However, the mechanical loading introduced by exercise, which is the mechanism of BMD changes, has not been investigated.
View Article and Find Full Text PDFBiol Sport
January 2025
Department of Training and Movement Science, Institute of Sport Science, Johannes Gutenberg-University Mainz, Mainz, Germany.
Despite the development of various motor learning models over many decades, the question of which model is most effective under which conditions to optimize the acquisition of skills remains a heated and recurring debate. This is particularly important in connection with learning sports movements with a high strength component. This study aims to examine the acute effects of various motor learning models on technical efficiency and force production during the Olympic snatch movement.
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