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Aging is known in all organisms that have different somatic and reproductive cells or in unicellular organisms that divide asymmetrically. Bacteria that divide symmetrically were believed to be immune to natural aging. The demonstration of functionally asymmetric division and aging in Escherichia coli recently has challenged this belief and led to the suggestion that aging might be inevitable for all life forms. We modeled the effects of symmetric and asymmetric division in bacteria to examine selective advantages of the alternative strategies of division. Aging of cell components was modeled by using a modified Leslie matrix framework. The model suggests that asymmetric division accompanied by aging and death of some cells results in a higher growth rate but a reduced growth yield. Symmetric division with or without gradual replacement of the old components, on the other hand, slows down the growth rate but may increase growth yield over a wide range of conditions. Thus, aging and immortality can be selected under different sets of conditions, and this selection may also lead to a tradeoff between growth rate and growth yield.
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http://dx.doi.org/10.1073/pnas.0606499103 | DOI Listing |
Nat Commun
September 2025
State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, 100875, China.
Rising atmospheric vapor pressure deficit (VPD)-a measure of atmospheric dryness, defined as the difference between saturated vapor pressure (SVP) and actual vapor pressure (AVP)-has been linked to increasing daily mean near-surface air temperatures since the 1980s. However, it remains unclear whether the faster increases in daily maximum temperature (T) relative to daily minimum temperature (T) have contributed to rising VPD. Here, we show that the faster rise in T compared with T over land has intensified VPD from 1980 to 2023.
View Article and Find Full Text PDFAdv Mater
September 2025
Center for Renewable Energy and Storage Technologies (CREST), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
The orientation of MXene flakes has received increasing research attention as it plays a critical role in determining the performance of MXene-based assemblies. Engineering MXene flakes into horizontal or vertical orientations can offer distinct advantages such as higher electrical conductivity, higher mechanical strength, and more efficient ion/molecule transport across the flakes. However, the benefits of horizontal and vertical orientations are mutually exclusive, and both of them possess structural symmetry that restricts their ability for stimuli-responsive deformation.
View Article and Find Full Text PDFJ Craniofac Surg
September 2025
Department of Neurological Sciences, Division of Maxillofacial Surgery, Marche University Hospital, Ancona.
Orthognathic surgery has undergone considerable evolution, marked by increasing prevalence and improved patient experience. Key advancements include shifting aesthetic ideals, the integration of digital technologies for surgical planning, and a growing emphasis on minimally invasive techniques. This study aimed to promote single-maxillary orthognathic surgery by implementing a novel, fully digital workflow protocol to reduce invasiveness.
View Article and Find Full Text PDFCell Death Differ
September 2025
Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan.
Nucleotide metabolism is essential for fundamental cellular functions such as growth, repair and proliferation. Emerging evidence suggests that metabolic pathways also influence programmed cell death (PCD), though the underlying mechanisms remain poorly understood. One model organism that has provided key insights into the regulation of PCD is Caenorhabditis elegans (C.
View Article and Find Full Text PDFMol Cell Endocrinol
September 2025
Reproductive Medicine Center, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China.
RNA-binding proteins (RBPs) are critical regulators of post-transcriptional gene expression and RNA processing during mammalian oocyte development. SERPINE1 mRNA-binding protein 1 (SERBP1), a conserved RNA-binding protein (RBP), exhibits prominent expression in the female reproductive system and throughout oogenesis. Conditional deletion of Serbp1 using oocyte-specific Zp3/Gdf9-Cre drivers resulted in arrested oocyte growth, female infertility, and failure of blastocyst formation from two-cell embryos.
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