scholarly journals Lipid anchoring and electrostatic interactions target the phospholipase NOT-LIKE-DAD to pollen endo-plasma membrane

2020 ◽  
Author(s):  
Laurine M. Gilles ◽  
Veronica La Padula ◽  
Nathanaël M.A. Jacquier ◽  
Jean-Pierre Martinant ◽  
Peter M. Rogowsky ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Electrostatic Interactions ◽  
Membrane Surface ◽  
Male Gamete ◽  
Targeted Mutagenesis ◽  
Major Constituent ◽  
Sperm Cells ◽  
Wild Type Female ◽  
Haploid Embryos ◽  
Membrane Surface Charge

AbstractPhospholipases are ubiquitous enzymes that cleave phospholipids, one major constituent of membranes. They are thus essential for many developmental processes, including male gamete development. In flowering plants, mutation of phospholipase NOT-LIKE-DAD (NLD) leads to peculiar defects in sexual reproduction. Indeed, pollination of a wild-type female with mutant pollen generates haploid embryos containing solely maternal genetic information. Contrary to previous reports NLD does not localize to cytosol and plasma membrane (PM) of sperm cells but to the pollen endo-plasma membrane (endo-PM), a specific membrane derived from the PM of the pollen vegetative cell that encircles the two sperm cells. Pharmacological approaches coupled with targeted mutagenesis revealed that lipid anchoring together with electrostatic interactions between membrane and NLD are involved in the attachment of NLD to this atypical endo-PM. Membrane surface-charge and anionic lipid bio-sensors indicated that phosphatidylinositol-4,5-bisphosphate (PIP(4,5)P2) is enriched in the endo-PM as compared to the PM. Our results uncover a unique example of how membrane electrostatic properties can specify a unique polar domain (i.e. endo-PM), which is critical for plant reproduction and gamete formation.

Lipid anchoring and electrostatic interactions target NOT-LIKE-DAD to pollen endo-plasma membrane

2021 ◽  
Vol 220 (10) ◽  
Author(s):  
Laurine M. Gilles ◽  
Andrea R.M. Calhau ◽  
Veronica La Padula ◽  
Nathanaël M.A. Jacquier ◽  
Claire Lionnet ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Electrostatic Interactions ◽  
Membrane Surface ◽  
Male Gamete ◽  
Targeted Mutagenesis ◽  
Sperm Cells ◽  
Apical Region ◽  
Haploid Embryos ◽  
Membrane Surface Charge ◽  
Specific Membrane

Phospholipases cleave phospholipids, major membrane constituents. They are thus essential for many developmental processes, including male gamete development. In flowering plants, mutation of phospholipase NOT-LIKE-DAD (NLD, also known as MTL or ZmPLA1) leads to peculiar defects in sexual reproduction, notably the induction of maternal haploid embryos. Contrary to previous reports, NLD does not localize to cytosol and plasma membrane of sperm cells but to the pollen endo-plasma membrane (endo-PM), a specific membrane derived from the PM of the pollen vegetative cell that encircles the two sperm cells. After pollen tube burst, NLD localizes at the apical region of the egg apparatus. Pharmacological approaches coupled with targeted mutagenesis revealed that lipid anchoring together with electrostatic interactions are involved in the attachment of NLD to this atypical endo-PM. Membrane surface-charge and lipid biosensors indicated that phosphatidylinositol-4,5-bisphosphate is enriched in the endo-PM, uncovering a unique example of how membrane electrostatic properties can define a specific polar domain (i.e., endo-PM), which is critical for plant reproduction and gamete formation.

scholarly journals Melatonin Effect on Cryopreserved Sperm Cells of Crioulo Stallions

2020 ◽  
Vol 5 (2) ◽  
pp. 1-8
Author(s):  
Eraldo L Zanella
Keyword(s):  
Plasma Membrane ◽  
Sperm Motility ◽  
Membrane Integrity ◽  
Male Gamete ◽  
The Body ◽  
Cellular Damage ◽  
Ros Generation ◽  
Sperm Cells ◽  
Beneficial Effects ◽  
Endogenous Antioxidant

The freezing/thawing process of spermatozoa can cause cellular damage to the male gamete, decreasing the fertilization potential due to the increase in the production of reactive oxygen species (ROS). Melatonin is a potent endogenous antioxidant that protects the body against the damage caused by ROS. This study has evaluated different melatonin concentrations on the sperm viability of cryopreserved semen of Crioulo stallions. For that, three ejaculates were collected from five stallions diluted in a commercial extender followed by centrifugation and resuspension in a commercial freezing extender supplemented with 0; 1.25; 2.5. 5mM of Melatonin before the cryopreservation process. After thawing, the evaluation was performed assessing motility and flow cytometry evaluations: the plasma membrane integrity (PI), the integrity of the acrosomal membrane (FITC-PNA), mitochondrial membrane potential (JC1), and ROS generation (DCF-DA). Our results showed that sperm motility in the group without Melatonin and the 1.25mM group did not show the difference; however, the groups 2.5mM and 5mM presented a reduction in sperm motility. The 1.25 mM concentration was able to protect the plasma membrane during the cryopreservation process, in addition to showing a significant reduction in the production of ROS and increasing the percentage of sperm with integral acrosome. It can also be seen that high concentrations of Melatonin did not show beneficial effects. In conclusion, the addition of 1.25 mM of the Melatonin in Crioulo sperm cells showed to have a protective effect on the sperm cell during cryopreservation.

scholarly journals Contribution of phosphatidylserine to membrane surface charge and protein targeting during phagosome maturation

2009 ◽  
Vol 185 (5) ◽  
pp. 917-928 ◽  
Author(s):  
Tony Yeung ◽  
Bryan Heit ◽  
Jean-Francois Dubuisson ◽  
Gregory D. Fairn ◽  
Basil Chiu ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Chlamydia Trachomatis ◽  
Surface Charge ◽  
Legionella Pneumophila ◽  
Protein Targeting ◽  
Membrane Surface ◽  
Phagosome Maturation ◽  
Cationic Proteins ◽  
Fluorescent Biosensor ◽  
Membrane Surface Charge

During phagocytosis, the phosphoinositide content of the activated membrane decreases sharply, as does the associated surface charge, which attracts polycationic proteins. The cytosolic leaflet of the plasma membrane is enriched in phosphatidylserine (PS); however, a lack of suitable probes has precluded investigation of the fate of this phospholipid during phagocytosis. We used a recently developed fluorescent biosensor to monitor the distribution and dynamics of PS during phagosome formation and maturation. Unlike the polyphosphoinositides, PS persists on phagosomes after sealing even when other plasmalemmal components have been depleted. High PS levels are maintained through fusion with endosomes and lysosomes and suffice to attract cationic proteins like c-Src to maturing phagosomes. Phagocytic vacuoles containing the pathogens Legionella pneumophila and Chlamydia trachomatis, which divert maturation away from the endolysosomal pathway, are devoid of PS, have little surface charge, and fail to recruit c-Src. These findings highlight a function for PS in phagosome maturation and microbial killing.

scholarly journals A combinatorial lipid code shapes the electrostatic landscape of plant endomembranes

2018 ◽  
Author(s):  
Matthieu Pierre Platre ◽  
Mehdi Doumane ◽  
Vincent Bayle ◽  
Mathilde Laetitia Audrey Simon ◽  
Lilly Maneta-Peyret ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Lipid Composition ◽  
Intracellular Trafficking ◽  
Membrane Surface ◽  
Endocytic Pathway ◽  
Surface Charges ◽  
Membrane Electrostatics ◽  
Phosphatidylinositol 4 ◽  
Membrane Surface Charge ◽  
Cellular Organelles

AbstractMembrane surface charge is critical for the transient, yet specific recruitment of proteins with polybasic regions to certain organelles. In all eukaryotes, the plasma membrane (PM) is the most electronegative compartment of the cell, which specifies its identity. As such, membrane electrostatics is a central parameter in signaling, intracellular trafficking and polarity. Here, we explore which are the lipids that control membrane electrostatics using plants as a model. We show that phosphatidic acidic (PA), phosphatidylserine (PS) and phosphatidylinositol-4-phosphate (PI4P) are separately required to generate the electrostatic signature of the plant PM. In addition, we reveal the existence of an electrostatic territory that is organized as a gradient along the endocytic pathway and is controlled by PS/PI4P combination. Altogether, we propose that combinatorial lipid composition of the cytosolic leaflet of cellular organelles not only defines the plant electrostatic territory but also distinguishes different compartments within this territory by specifying their varying surface charges.

scholarly journals Tau and Membranes: Interactions That Promote Folding and Condensation

2021 ◽  
Vol 9 ◽  
Author(s):  
Chad A. Sallaberry ◽  
Barbie J. Voss ◽  
Jaroslaw Majewski ◽  
Jacek Biernat ◽  
Eckhard Mandelkow ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Phase Separation ◽  
Electrostatic Interactions ◽  
Membrane Surface ◽  
Cellular Functions ◽  
Cell Transport ◽  
Repeat Domain ◽  
A Site ◽  
Β Sheet ◽  
Powerful Mechanism

Tau misfolding and assembly is linked to a number of neurodegenerative diseases collectively described as tauopathies, including Alzheimer’s disease (AD) and Parkinson’s disease. Anionic cellular membranes, such as the cytosolic leaflet of the plasma membrane, are sites that concentrate and neutralize tau, primarily due to electrostatic interactions with tau’s microtubule binding repeat domain (RD). In addition to electrostatic interactions with lipids, tau also has interactions with membrane proteins, which are important for tau’s cellular functions. Tau also interacts with lipid tails to facilitate direct translocation across the membrane and can form stable protein-lipid complexes involved in cell-to-cell transport. Concentrated tau monomers at the membrane surface can form reversible condensates, change secondary structures, and induce oligomers, which may eventually undergo irreversible crosslinking and fibril formation. These β-sheet rich tau structures are capable of disrupting membrane organization and are toxic in cell-based assays. Given the evidence for relevant membrane-based tau assembly, we review the emerging hypothesis that polyanionic membranes may serve as a site for phase-separated tau condensation. Membrane-mediated phase separation may have important implications for regulating tau folding/misfolding, and may be a powerful mechanism to spatially direct tau for native membrane-mediated functions.

Charge Characteristics of Nanofiltration Membrane by Streaming Potential Method

2011 ◽  
Vol 396-398 ◽  
pp. 547-551 ◽  
Author(s):  
Bao Wei Su ◽  
Xiao Jie Duan ◽  
Mao Wei Dou ◽  
Xue Li Gao ◽  
Cong Jie Gao
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Surface Charge Density ◽  
Electrostatic Interactions ◽  
Membrane Surface ◽  
Streaming Potential ◽  
Freundlich Isotherm ◽  
Potential Method ◽  
Nanofiltration Membrane ◽  
Membrane Surface Charge

Surface charge properties of DL nanofiltration membrane were studied using streaming potential method. The results indicate that in the experimental concentration range, the relationship between NF membrane surface charge density and electrolyte solution concentration is in good agreement with Freundlich-isotherm adsorption, which indicates that the membrane surface charge comes from the adsorption of ions of the solution. In addition, the analysis of anion and cation adsorption on nanofiltration membrane surface showed that adsorption of common ions to the Inner Helmholtz Plane through specific adsorption increases the charge density, while adsorption of counter ions to the Outer Helmholtz Plane through electrostatic interactions leads to electric double-layer contracting inward, decreasing the membrane surface charge density.

scholarly journals Nanometals-Containing Polymeric Membranes for Purification Processes

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 513
Author(s):  
Anna Rabajczyk ◽  
Maria Zielecka ◽  
Krzysztof Cygańczuk ◽  
Łukasz Pastuszka ◽  
Leszek Jurecki
Keyword(s):  
Synergistic Effects ◽  
Membrane Surface ◽  
Antibacterial Properties ◽  
Polymeric Membranes ◽  
Treatment Processes ◽  
Wide Range ◽  
Different Types ◽  
Type Size ◽  
Titanium Zinc ◽  
Membrane Surface Charge

A recent trend in the field of membrane research is the incorporation of nanoparticles into polymeric membranes, which could produce synergistic effects when using different types of materials. This paper discusses the effect of the introduction of different nanometals such as silver, iron, silica, aluminum, titanium, zinc, and copper and their oxides on the permeability, selectivity, hydrophilicity, conductivity, mechanical strength, thermal stability, and antiviral and antibacterial properties of polymeric membranes. The effects of nanoparticle physicochemical properties, type, size, and concentration on a membrane’s intrinsic properties such as pore morphology, porosity, pore size, hydrophilicity/hydrophobicity, membrane surface charge, and roughness are discussed, and the performance of nanocomposite membranes in terms of flux permeation, contaminant rejection, and antifouling capability are reviewed. The wide range of nanocomposite membrane applications including desalination and removal of various contaminants in water-treatment processes are discussed.

scholarly journals Vacuolar-type H+-ATPase regulates cytoplasmic pH in Toxoplasma gondii tachyzoites

1998 ◽  
Vol 330 (2) ◽  
pp. 853-860 ◽  
Author(s):  
N. J. Silvia MORENO ◽  
Li ZHONG ◽  
Hong-Gang LU ◽  
Wanderley DE SOUZA ◽  
Marlene BENCHIMOL
Keyword(s):  
Plasma Membrane ◽  
Toxoplasma Gondii ◽  
Laser Scanning ◽  
Membrane Surface ◽  
Surface Proteins ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Dependent Manner ◽  
Cytoplasmic Ph ◽  
Bafilomycin A1

Cytoplasmic pH (pHi) regulation was studied in Toxoplasma gondii tachyzoites by using the fluorescent dye 2ʹ,7ʹ-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein. Their mean baseline pHi (7.07±0.06; n = 5) was not significantly affected in the absence of extracellular Na+, K+ or HCO3- but was significantly decreased in a dose-dependent manner by low concentrations of N,Nʹ-dicyclohexylcarbodi-imide (DCCD), N-ethylmaleimide (NEM) or bafilomycin A1. Bafilomycin A1 also inhibited the recovery of tachyzoite pHi after an acid load with sodium propionate. Similar concentrations of DCCD, NEM and bafilomycin A1 produced depolarization of the plasma membrane potential as measured with bis-(1,3-diethylthiobarbituric)trimethineoxonol (bisoxonol), and DCCD prevented the hyperpolarization that accompanies acid extrusion after the addition of propionate, in agreement with the electrogenic nature of this pump. Confocal laser scanning microscopy indicated that, in addition to being located in cytoplasmic vacuoles, the vacuolar (V)-H+-ATPase of T. gondii tachyzoites is also located in the plasma membrane. Surface localization of the V-H+-ATPase was confirmed by experiments using biotinylation of cell surface proteins and immunoprecipitation with antibodies against V-H+-ATPases. Taken together, the results are consistent with the presence of a functional V-H+-ATPase in the plasma membrane of these intracellular parasites and with an important role of this enzyme in the regulation of pHi homoeostasis in these cells.

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