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1. MLO ‐mediated Ca ²⁺ influx regulates root hair tip growth in Arabidopsis

   https://doi.org/10.1111/nph.70378  

   Ogawa, Sienna T; Zhang, Weiwei; Staiger, Christopher J; Kessler, Sharon A (December 2025, New Phytologist)

   Summary Root hair tip‐growth involves coordinated Ca²⁺and ROS signaling to promote growth while maintaining tip integrity. MILDEW RESISTANCE LOCUS‐O (MLO) proteins act downstream of FERONIA (FER) receptor‐like kinases in pollen tubes and synergids to regulate calcium dynamics. This study uses a constitutively active MLO (faNTA) to identify a new role for the FER/MLO signaling module in regulating [Ca²⁺]_cytoscillations in growing root hairs.faNTA was used as a tool to manipulate Ca²⁺influx infermutants. Light sheet fluorescence imaging was used to image the reporter R‐GECO1 to observe [Ca²⁺]_cytdynamics during root hair elongation in various genotypes.We show that faNTA is sufficient to restore normal root hair development, [Ca²⁺]_cytoscillations, and ROS levels tofer‐4. MLO15 was identified as a regulator of root hair tip growth based on disrupted root hair growth and [Ca²⁺]_cytsignatures inmlo15‐4. We also link the FER/MLO module to ROS accumulation by showing that faNTA is sufficient to restore ROS levels infer‐4root hairs, but is unable to complement the burst root hairs ofrbohc.We propose that MLOs act downstream of FER to mediate Ca²⁺influx and promote ROS production to regulate root hair tip growth. 

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2. An Extracellular, Ca ²⁺ ‐Activated Nuclease ( EcnA ) Mediates Transformation in a Naturally Competent Archaeon

   https://doi.org/10.1111/mmi.15311  

   Fonseca, Dallas R; Day, Leslie A; Crone, Kathryn K; Costa, Kyle C (October 2024, Molecular Microbiology)

   ABSTRACT Transformation, the uptake of DNA directly from the environment, is a major driver of gene flow in microbial populations. In bacteria, DNA uptake requires a nuclease that processes dsDNA to ssDNA, which is subsequently transferred into the cell and incorporated into the genome. However, the process of DNA uptake in archaea is still unknown. Previously, we cataloged genes essential to natural transformation inMethanococcus maripaludis, but few homologs of bacterial transformation‐associated genes were identified. Here, we characterize one gene, MMJJ_16440 (named here asecnA), to be an extracellular nuclease. We show that EcnA is Ca²⁺‐activated, present on the cell surface, and essential for transformation. While EcnA can degrade several forms of DNA, the highest activity was observed with ssDNA as a substrate. Activity was also observed with circular dsDNA, suggesting that EcnA is an endonuclease. This is the first biochemical characterization of a transformation‐associated protein in a member of the archaeal domain and suggests that both archaeal and bacterial transformation initiate in an analogous fashion. 

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3. Ca ²⁺ release or Ca ²⁺ entry, that is the question: what governs Ca ²⁺ oscillations in pancreatic β cells?

   https://doi.org/10.1152/ajpendo.00030.2023  

   Fletcher, Patrick A.; Thompson, Ben; Liu, Chanté; Bertram, Richard; Satin, Leslie S.; Sherman, Arthur S. (June 2023, American Journal of Physiology-Endocrinology and Metabolism)

   The standard model for Ca 2+ oscillations in insulin-secreting pancreatic β cells centers on Ca 2+ entry through voltage-activated Ca 2+ channels. These work in combination with ATP-dependent K + channels, which are the bridge between the metabolic state of the cells and plasma membrane potential. This partnership underlies the ability of the β cells to secrete insulin appropriately on a minute-to-minute time scale to control whole body plasma glucose. Though this model, developed over more than 40 years through many cycles of experimentation and mathematical modeling, has been very successful, it has been challenged by a hypothesis that calcium-induced calcium release from the endoplasmic reticulum through ryanodine or inositol trisphosphate (IP3) receptors is instead the key driver of islet oscillations. We show here that the alternative model is in fact incompatible with a large body of established experimental data and that the new observations offered in support of it can be better explained by the standard model. 

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4. Molecular and electrophysiological characterization of anion transport in Arabidopsis thaliana pollen reveals regulatory roles for pH , Ca ²⁺ and GABA

   https://doi.org/10.1111/nph.15863  

   Domingos, Patrícia; Dias, Pedro N.; Tavares, Bárbara; Portes, Maria Teresa; Wudick, Michael M.; Konrad, Kai R.; Gilliham, Matthew; Bicho, Ana; Feijó, José A. (May 2019, New Phytologist)
5. A model of cardiac ryanodine receptor gating predicts experimental Ca ²⁺ -dynamics and Ca ²⁺ -triggered arrhythmia in the long QT syndrome

   https://doi.org/10.1063/1.5000711  

   Wilson, Dan; Ermentrout, Bard; Němec, Jan; Salama, Guy (September 2017, Chaos: An Interdisciplinary Journal of Nonlinear Science)