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Grünhofer P, Schreiber L. Cutinized and suberized barriers in leaves and roots: Similarities and differences. JOURNAL OF PLANT PHYSIOLOGY 2023; 282:153921. [PMID: 36780757 DOI: 10.1016/j.jplph.2023.153921] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 11/18/2022] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
Anatomical, histochemical, chemical, and biosynthetic similarities and differences of cutinized and suberized plant cell walls are presented and reviewed in brief. Based on this, the functional properties of cutinized and suberized plant cell walls acting as transport barriers are compared and discussed in more detail. This is of general importance because fundamental misconceptions about relationships in plant-environment water relations are commonly encountered in the scientific literature. It will be shown here, that cuticles represent highly efficient apoplastic transport barriers significantly reducing the diffusion of water and dissolved compounds. The transport barrier of cuticles is mainly established by the deposition of cuticular waxes. Upon wax extraction, with the cutin polymer remaining, cuticular permeability for water and dissolved non-ionized and lipophilic solutes are increasing by 2-3 orders of magnitude, whereas polar and charged substances (e.g., nutrient ions) are only weakly affected (2- to 3-fold increases in permeability). Suberized apoplastic barriers without the deposition of wax are at least as permeable as the cutin polymer matrix without waxes and hardly offer any resistance to the free movement of water. Only upon the deposition of significant amounts of wax, as it is the case with suberized periderms exposed to the atmosphere, an efficient transport barrier for water can be established by suberized cell walls. Comparing the driving forces (gradients between water potentials inside leaves and roots and the surrounding environment) for water loss acting on leaves and roots, it is shown that leaves must have a genetically pre-defined highly efficient transpiration barrier fairly independent from rapidly changing environmental influences. Roots, in most conditions facing a soil environment with relative humidities very close to 100%, are orders of magnitude more permeable to water than leaf cuticles. Upon desiccation, the permanent wilting point of plants is defined as -1.5 MPa, which still corresponds to nearly 99% relative humidity in soil. Thus, the main reason for plant water stress leading to dehydration is the inability of root tissues to decrease their internal water potential to values more negative than -1.5 MPa and not the lack of a transport barrier for water in roots and leaves. Taken together, the commonly mentioned concepts that a drought-induced increase of cuticular wax or root suberin considerably strengthens the apoplastic leaf or root transport barriers and thus aids in water conservation appears highly questionable.
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Affiliation(s)
- Paul Grünhofer
- Department of Ecophysiology, Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115, Bonn, Germany.
| | - Lukas Schreiber
- Department of Ecophysiology, Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115, Bonn, Germany.
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Boudreault F, Tan JJ, Grygorczyk R. Propidium uptake and ATP release in A549 cells share similar transport mechanisms. Biophys J 2022; 121:1593-1609. [PMID: 35398020 PMCID: PMC9117937 DOI: 10.1016/j.bpj.2022.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 03/03/2022] [Accepted: 04/04/2022] [Indexed: 11/02/2022] Open
Abstract
The lipid bilayer of eukaryotic cells' plasma membrane is almost impermeable to small ions and large polar molecules, but its miniscule basal permeability in intact cells is poorly characterized. This report describes the intrinsic membrane permeability of A549 cells toward the charged molecules propidium (Pr2+) and ATP4-. Under isotonic conditions, we detected with quantitative fluorescence microscopy, a continuous low-rate uptake of Pr (∼150 × 10-21 moles (zmol)/h/cell, [Pr]o = 150 μM, 32°C). It was stimulated transiently but strongly by 66% hypotonic cell swelling reaching an influx amplitude of ∼1500 (zmol/h)/cell. The progressive Pr uptake with increasing [Pr]o (30, 150, and 750 μM) suggested a permeation mechanism by simple diffusion. We quantified separately ATP release with custom wide-field-of-view chemiluminescence imaging. The strong proportionality between ATP efflux and Pr2+ influx during hypotonic challenge, and the absence of stimulation of transmembrane transport following 300% hypertonic shock, indicated that ATP and Pr travel the same conductive pathway. The fluorescence images revealed a homogeneously distributed intracellular uptake of Pr not consistent with high-conductance channels expressed at low density on the plasma membrane. We hypothesized that the pathway consists of transiently formed water pores evenly spread across the plasma membrane. The abolition of cell swelling-induced Pr uptake with 500 μM gadolinium, a known modulator of membrane fluidity, supported the involvement of water pores whose formation depends on the membrane fluidity. Our study suggests an alternative model of a direct permeation of ATP (and other molecules) through the phospholipid bilayer, which may have important physiological implications.
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Freire V, Lattanzio G, Orera I, Mañas P, Cebrián G. Component release after exposure of Staphylococcus aureus cells to pulsed electric fields. INNOV FOOD SCI EMERG 2021. [DOI: 10.1016/j.ifset.2021.102838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Galizzi G, Palumbo L, Amato A, Conigliaro A, Nuzzo D, Terzo S, Caruana L, Picone P, Alessandro R, Mulè F, Di Carlo M. Altered insulin pathway compromises mitochondrial function and quality control both in in vitro and in vivo model systems. Mitochondrion 2021; 60:178-188. [PMID: 34454074 DOI: 10.1016/j.mito.2021.08.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/13/2021] [Accepted: 08/23/2021] [Indexed: 11/15/2022]
Abstract
Altered insulin signaling and insulin resistance are considered the link between Alzheimer's disease (AD) and metabolic syndrome. Here, by using an in vitro and an in vivo model, we investigated the relationship between these disorders focusing on neuronal mitochondrial dysfunction and mitophagy. In vitro Aβ insult induced the opening of mitochondrial permeability transition pore (mPTP), mitochondrial membrane potential (ΔΨm) loss, and apoptosis while insulin addition ameliorated these dysfunctions. The same alterations were detected in a 16 weeks of age mouse model of diet-induced obesity and insulin resistance. In addition, we detected an increase of fission related proteins and activation of mitophagy, proved by the rise of PINK1 and Parkin proteins. Nevertheless, in vitro, the increase of p62 and LC3 indicated an alteration in autophagy, while, in vivo decreased expression of p62 and increase of LC3 suggested removing of damaged mitochondria. Finally, in aged mice (28 and 48 weeks), the data indicated impairment of mitophagy and suggested the accumulation of damaged mitochondria. Taken together these outcomes indicate that alteration of the insulin pathway affects mitochondrial integrity, and effective mitophagy is age-dependent.
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Affiliation(s)
- Giacoma Galizzi
- Istituto per la Ricerca e l'Innovazione Biomedica (IRIB), CNR, via U. La Malfa 153, 90146 Palermo, Italy
| | - Laura Palumbo
- Istituto per la Ricerca e l'Innovazione Biomedica (IRIB), CNR, via U. La Malfa 153, 90146 Palermo, Italy
| | - Antonella Amato
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, viale delle Scienze, 90128 Palermo, Italy
| | - Alice Conigliaro
- Dipartimento di Biomedicina, Neuroscienze e Diagnostica Avanzata (Bi.N.D.), Università degli Studi di Palermo, via del Vespro 129, 90127 Palermo, Italy
| | - Domenico Nuzzo
- Istituto per la Ricerca e l'Innovazione Biomedica (IRIB), CNR, via U. La Malfa 153, 90146 Palermo, Italy
| | - Simona Terzo
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, viale delle Scienze, 90128 Palermo, Italy; Dipartimento di Biomedicina, Neuroscienze e Diagnostica Avanzata (Bi.N.D) (sez. Anatomia Umana) Università degli Studi di Palermo, via del Vespro 129, 90127 Palermo, Italy
| | - Luca Caruana
- Istituto per la Ricerca e l'Innovazione Biomedica (IRIB), CNR, via U. La Malfa 153, 90146 Palermo, Italy
| | - Pasquale Picone
- Istituto per la Ricerca e l'Innovazione Biomedica (IRIB), CNR, via U. La Malfa 153, 90146 Palermo, Italy
| | - Riccardo Alessandro
- Istituto per la Ricerca e l'Innovazione Biomedica (IRIB), CNR, via U. La Malfa 153, 90146 Palermo, Italy; Dipartimento di Biomedicina, Neuroscienze e Diagnostica Avanzata (Bi.N.D.), Università degli Studi di Palermo, via del Vespro 129, 90127 Palermo, Italy
| | - Flavia Mulè
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, viale delle Scienze, 90128 Palermo, Italy
| | - Marta Di Carlo
- Istituto per la Ricerca e l'Innovazione Biomedica (IRIB), CNR, via U. La Malfa 153, 90146 Palermo, Italy.
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Malik C, Ghosh S. Regulation of Single-Channel Conductance of Voltage-Dependent Anion Channel by Mercuric Chloride in a Planar Lipid Bilayer. J Membr Biol 2020; 253:357-371. [PMID: 32748041 DOI: 10.1007/s00232-020-00134-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/24/2020] [Indexed: 11/26/2022]
Abstract
The existence of mercury in various forms, e.g., elemental, organic, and inorganic has been known for decades. In any of these forms, it is poisonous to metabolism. In this, an investigation about the effect of the inorganic form of mercury, i.e., mercuric chloride (HgCl2) to the mitochondrial voltage-dependent anion channel (VDAC), has been done after isolation from the cardiac and brain tissues of Wistar rats. In vitro electrophysiology experiments were performed in Cardiolipin planar lipid bilayer membrane (BLM) to study the change in the conductance, selectivity, and gating charge of VDAC post HgCl2 treatment. A reduction in mean conductance of VDAC from 4.3 ± 0.18 to 1.66 ± 0.11 nS was observed. Further, the Gating charge calculated before (± 3.5) and after HgCl2 treatment (± 2.3) showed significant difference. Later, VDAC's behavior was studied at different concentrations of HgCl2 ranging from 0.1 μM to 1 mM. The Inhibitory concentration (IC50) was calculated from the linear regression plot. The IC50 was found to be 488.1 μM. In the asymmetrical HgCl2 (5:1), a permeability ratio of cation to anion was found to be 4.2. It is interpreted that VDAC functioning is affected due to the application of 4 mM HgCl2 and a reduction in the conductance, gating charge, and permeability of VDAC was detected. The results provide clues to HgCl2-induced toxicity mediated through VDAC in the Cardiolipin BLM.
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Affiliation(s)
- Chetan Malik
- Department of Biophysics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Subhendu Ghosh
- Department of Biophysics, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
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Dawid C, Weber D, Musiol E, Janas V, Baur S, Lang R, Fromme T. Comparative assessment of purified saponins as permeabilization agents during respirometry. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148251. [PMID: 32598881 DOI: 10.1016/j.bbabio.2020.148251] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/26/2020] [Accepted: 06/12/2020] [Indexed: 01/15/2023]
Abstract
Saponins are a diverse group of secondary plant metabolites, some of which display hemolytic toxicity due to plasma membrane permeabilization. This feature is employed in biological applications for transferring hydrophilic molecules through cell membranes. Widely used commercial saponins include digitonin and saponins from soap tree bark, both of which constitute complex mixtures of little definition. We assessed the permeabilization power of pure saponins towards cellular membranes in an effort to detect novel properties and to improve existing applications. In a respirometric assay, we characterized half-maximal permeabilization of the plasma membrane for different metabolites, of the mitochondrial outer membrane for cytochrome C and the full solubilization of mitochondrial inner membrane protein complexes. Beyond the complete list as repository for the field, we highlight several findings with direct applicability. First, we identified and validated α-chaconine as alternative permeabilization agent in respirometric assays of cultured cells and isolated synaptosomes, superior to digitonin in its tolerability for mitochondria. Second, we identified glycyrrhizic acid to form exceptionally small pores impermeable for adenosine diphosphate. Third, in a concentration dependent manner, tomatine proved to be able to selectively permeabilize the mitochondrial outer, but not inner membrane, allowing for novel states in which to determine cytochrome C oxidase activity. In summary, we provide a list of the permeabilization properties of 18 pure saponins. The identification of two saponins, namely tomatine and chaconine, with direct usability in improved or novel cell biological applications within this small subgroup demonstrates the tremendous potential for further functional screening of pure saponins.
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Affiliation(s)
- Corinna Dawid
- Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich, Freising, Germany
| | - Daniela Weber
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Eva Musiol
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Vanessa Janas
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Sebastian Baur
- Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich, Freising, Germany
| | - Roman Lang
- Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich, Freising, Germany
| | - Tobias Fromme
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Freising, Germany; EKFZ - Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Freising, Germany.
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Gupta R, Ghosh S. Phosphorylation of voltage-dependent anion channel by c-Jun N-terminal Kinase-3 leads to closure of the channel. Biochem Biophys Res Commun 2015; 459:100-6. [PMID: 25721670 DOI: 10.1016/j.bbrc.2015.02.077] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 02/15/2015] [Indexed: 01/30/2023]
Abstract
Stress activated c-Jun N-terminal Kinase-3 (JNK3) has been reported to act on mitochondrion to promote neuronal cell death. Phosphorylation of mitochondrial Voltage-Dependent Anion Channel (VDAC) plays an important role in mitochondria-mediated cell death. Keeping these in view phosphorylation of rat brain VDAC by JNK3 has been studied in vitro. Pro Q Diamond phospho-protein staining experiment demonstrates VDAC is phosphorylated by JNK3. Bilayer electrophysiological experiments show that single-channel conductance of VDAC phosphorylated by JNK3 is significantly lower than that of the native VDAC at a membrane potential. The opening probability of VDAC undergoes massive reduction due to phosphorylation by JNK3. These indicate closure of VDAC due to phosphorylation by JNK3. Treatment of phosphorylated VDAC with alkaline phosphatase reversed the VDAC functional activity as shown by single-channel current and opening probability. The physiological consequence of closure of VDAC as a result of phosphorylation has been attributed to JNK3 dependent mitochondria-mediated apoptosis.
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Affiliation(s)
- Rajeev Gupta
- Department of Biophysics, University of Delhi South Campus, New Delhi, India
| | - Subhendu Ghosh
- Department of Biophysics, University of Delhi South Campus, New Delhi, India.
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