ORCID Profile
0000-0003-3799-7214
Current Organisations
University of Melbourne
,
University of Oxford
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Publisher: MyJove Corporation
Date: 18-04-2018
DOI: 10.3791/56817
Publisher: Elsevier BV
Date: 2023
DOI: 10.1016/J.MBS.2022.108923
Abstract: Calcium (Ca
Publisher: Cold Spring Harbor Laboratory
Date: 05-08-2022
DOI: 10.1101/2022.08.04.502830
Abstract: Companion cells and sieve elements play an essential role in vascular plants and yet the details of the metabolism that underpins their function remain largely unknown. Here we construct a tissue-scale flux balance analysis (FBA) model to describe the metabolism of phloem loading in a mature Arabidopsis leaf. We explore the potential metabolic interactions between mesophyll cells, companion cells, and sieve elements based on current understanding of the physiology of phloem tissue and through the use of cell-type-specific transcriptome data as a weighting in our model. We find that companion cell chloroplasts likely play a very different role to mesophyll chloroplasts. Our model suggests that, rather than carbon capture, the most crucial function of companion cell chloroplasts is to provide photosynthetically-generated ATP to the cytosol. Additionally, our model predicts that the metabolites imported into the companion cell are not necessarily the same metabolites that are exported in phloem sap phloem loading is more efficient if certain amino acids are synthesised in the phloem tissue. Surprisingly, in our model predictions the H + -PP i ase is the more important contributor than the H + ATPase to the energisation of the companion cell plasma membrane.
Publisher: Elsevier BV
Date: 05-2023
Publisher: Elsevier BV
Date: 09-2020
Publisher: Oxford University Press (OUP)
Date: 11-03-2023
Abstract: Companion cells and sieve elements play an essential role in vascular plants, and yet the details of the metabolism that underpins their function remain largely unknown. Here, we construct a tissue-scale flux balance analysis (FBA) model to describe the metabolism of phloem loading in a mature Arabidopsis (Arabidopsis thaliana) leaf. We explore the potential metabolic interactions between mesophyll cells, companion cells, and sieve elements based on the current understanding of the physiology of phloem tissue and through the use of cell type–specific transcriptome data as a weighting in our model. We find that companion cell chloroplasts likely play a very different role to mesophyll chloroplasts. Our model suggests that, rather than carbon capture, the most crucial function of companion cell chloroplasts is to provide photosynthetically generated ATP to the cytosol. Additionally, our model predicts that the metabolites imported into the companion cell are not necessarily the same metabolites that are exported in phloem sap phloem loading is more efficient if certain amino acids are synthesized in the phloem tissue. Surprisingly, in our model predictions, the proton-pumping pyrophosphatase (H+-PPiase) is a more efficient contributor to the energization of the companion cell plasma membrane than the H+-ATPase.
Publisher: Cold Spring Harbor Laboratory
Date: 14-08-2020
DOI: 10.1101/2020.08.13.249144
Abstract: Calcium (Ca 2+ ) plays a critical role in the excitation contraction coupling (ECC) process that governs the contraction of cardiomyocytes during each heartbeat. While ryanodine receptors (RyRs) are the primary Ca 2+ channels responsible for mediating cell-wide Ca 2+ transients during ECC, Ca 2+ release via inositol 1,4,5-trisphosphate (IP 3 ) receptors (IP 3 Rs) have been reported to elicit ECC-modulating effects. Recent studies suggest that the proximal localization of IP 3 Rs at dyads grants their ability to modify the occurrence of Ca 2+ sparks (elementary Ca 2+ release events that constitute ECC-associated Ca 2+ transients) which may underlie the modulatory effects on ECC. Here, we aim to uncover the mechanism by which IP 3 Rs affect Ca 2+ spark dynamics. To this end, we developed a mathematical model of the dyad that incorporates IP 3 Rs to reveal their impact on local Ca 2+ handling and corresponding Ca 2+ spark formation. Consistent with published experimental data, our model predicts that the propensity for Ca 2+ spark formation increases with IP 3 R activity. Our simulations support the hypothesis that IP 3 R activity elevates Ca 2+ within the dyad, sensitizing proximal RyRs for future release. However, this lowers Ca 2+ in the JSR available for release and thus results in Ca 2+ sparks with the same duration but lower litudes.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Hilary Hunt.