Proliferating cells adjust their cell size depending on the nutritional environment. Cells are large in rich media and small in poor media. This physiological response has been demonstrated in both unicellular and multicellular organisms. Here we show that the greatwall-endosulfine (Ppk18-Igo1 in fission yeast) pathway couples the nutritional environment to the cell-cycle machinery by regulating the activity of PP2A·B55. In the presence of nutrients, greatwall (Ppk18) protein kinase is inhibited by TORC1 and PP2A·B55 is active. High levels of PP2A·B55 prevent the activation of mitotic Cdk1·Cyclin B, and cells increase in size in G2 before they undergo mitosis. When nutrients are limiting, TORC1 activity falls off, and the activation of greatwall (Ppk18) leads to the phosphorylation of endosulfine (Igo1) and inhibition of PP2A·B55, which in turn allows full activation of Cdk1·CyclinB and entry into mitosis with a smaller cell size. Given the conservation of this pathway, it is reasonable to assume that this mechanism operates in higher eukaryotes, as well.
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http://dx.doi.org/10.1016/j.cub.2015.12.035 | DOI Listing |
Tissue Eng Regen Med
January 2025
College of Materials Science and Engineering, Hunan University, Changsha, 410072, People's Republic of China.
Background: Tissue engineering holds promise for vascular repair and regeneration by mimicking the extracellular matrix of blood vessels. However, achieving a functional and thick vascular wall with aligned fiber architecture by electrospinning remains a significant challenge.
Methods: A novel electrospinning setup was developed that utilizes an auxiliary electrode and a spring.
Curr Microbiol
January 2025
Department of Microbiology, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand.
An aerobic, Gram-stain-positive, motile, coccus-shaped actinomycete, designated strain LSe6-4, was isolated from leaves of sea purslane (Sesuvium portulacastrum L.) in Thailand and subjected to a polyphasic taxonomic studies. Growth of the strain occurred at temperatures between 15 and 38 °C, and with NaCl concentrations 0-13%.
View Article and Find Full Text PDFAnal Methods
November 2017
Agricultural and Biological Engineering Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA.
Nitric oxide (NO) is an important signaling molecule that is involved in stress response, homeostasis, host defense, and cell development. In most cells, NO levels are in the femtomolar to micromolar range, with extracellular concentrations being much lower. Thus, real time measurement of spatiotemporal NO dynamics near the surface of living cells/tissues is a major challenge.
View Article and Find Full Text PDFJ Nanobiotechnology
January 2025
School of Medicine, Shanghai University, Shanghai, 200444, China.
Biochips are widely applied to manipulate the geometrical morphology of stem cells in recent years. Patterned antenna-like pseudopodia are also probed to explore the influence of pseudopodia formation on gene delivery and expression on biochips. However, how the antenna-like pseudopodia affect gene transfection is unsettled and the underlying trafficking mechanism of exogenous genes in engineered single cells is not announced.
View Article and Find Full Text PDFJ Orthop Surg Res
January 2025
Xuzhou Medical University Affiliated Stomatology Hospital, Xuzhou, 221002, Jiangsu Province, China.
Purpose: We aimed to explore the mechanism by which Boron-doped nano-hydroxyapatite (B-nHAp) facilitates the proliferation and differentiation of osteoblasts through controlled release of B.
Methods: B-nHAp characterization was accomplished by means of X-ray diffraction, scanning electron microscopy, inductively coupled plasma mass spectrometry, and transmission electron microscopy. Human bone marrow mesenchymal stem cells (hBMSCs) were subjected to flow cytometry, alizarin red S staining, and cell counting kit-8 assay for proliferation and differentiation determination.
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