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1.
Nat Rev Mol Cell Biol ; 21(3): 151-166, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32034394

RESUMO

During division, eukaryotic cells undergo a dramatic, complex and coordinated remodelling of their cytoskeleton and membranes. For cell division to occur, chromosomes must be segregated and new cellular structures, such as the spindle apparatus, must be assembled. Pre-existing organelles, such as the nuclear envelope, endoplasmic reticulum and Golgi apparatus, must be disassembled or remodelled, distributed and reformed. Smaller organelles such as mitochondria as well as cytoplasmic content must also be properly distributed between daughter cells. This mixture of organelles and cytoplasm is bound by a plasma membrane that is itself subject to remodelling as division progresses. The lipids resident in these different membrane compartments play important roles in facilitating the division process. In recent years, we have begun to understand how membrane remodelling is coordinated during division; however, there is still much to learn. In this Review, we discuss recent insights into how these important cellular events are performed and regulated.


Assuntos
Divisão Celular/fisiologia , Membranas/metabolismo , Organelas/fisiologia , Animais , Membrana Celular/metabolismo , Retículo Endoplasmático/metabolismo , Endossomos/metabolismo , Células Eucarióticas/citologia , Complexo de Golgi/metabolismo , Humanos , Membranas/fisiologia , Microtúbulos/metabolismo , Mitocôndrias/metabolismo , Organelas/metabolismo , Fuso Acromático/metabolismo
3.
Biochim Biophys Acta Biomembr ; 1861(12): 183060, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499020

RESUMO

In recent years, hopanoids, a group of pentacyclic compounds found in bacterial membranes, are in the spotlight since it was proposed that they induce order in lipid membranes in a similar way cholesterol do in eukaryotes, despite their structural differences. We studied here whether diplopterol (an abundant hopanoid) promoted similar effects on model membranes as sterols do. We analyzed the compaction, dynamics, phase segregation, permeability and compressibility of model membranes containing diplopterol, and compared with those containing sterols from animals, plants and fungi. We also tested the effect that the incubation with diplopterol had on hopanoid-lacking bacteria. Our results show that diplopterol induces phase segregation, increases lipid compaction, and decreases permeability on phospholipid membranes, while retaining membrane fluidity and compressibility. Furthermore, the exposition to this hopanoid decreases the permeability of the opportunistic pathogen Pseudomonas aeruginosa and increases the resistance to antibiotics. All effects promoted by diplopterol were similar to those generated by the sterols. Our observations add information on the functional significance of hopanoids as molecules that play an important role in membrane organization and dynamics in model membranes and in a bacterial system.


Assuntos
Permeabilidade da Membrana Celular/fisiologia , Membrana Celular/química , Triterpenos/metabolismo , Membrana Celular/fisiologia , Permeabilidade da Membrana Celular/efeitos dos fármacos , Bicamadas Lipídicas/química , Lipídeos de Membrana/química , Lipídeos de Membrana/fisiologia , Membranas/química , Membranas/fisiologia , Modelos Biológicos , Permeabilidade , Fosfolipídeos/química , Fosfolipídeos/fisiologia , Pseudomonadaceae/metabolismo , Esteróis/química , Triterpenos/farmacologia
4.
Health Phys ; 117(5): 532-540, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31211753

RESUMO

The action of free radicals is believed responsible for much or most biological injury resulting from exposure to ionizing radiation. These molecules in solution possess short lifetimes on the order of nanoseconds to microseconds. As a result, the dose-which measures the energy dissipated in tissue due to radiolysis-should not be considered a reliable indicator of the free radical concentration, nor of the chemical effects that follow from it. Rather, the chemical state of affected tissue is properly represented only by the dissipated power, which describes the distribution of energy with time. The present report demonstrates the validity of this assertion using data contained in a report describing a benchtop experiment published in 1972. The experiment used the visible rupture of a model phospholipid membrane as a means to quantify the degree of chemical insult caused by ionizing radiation. The experiment found that beta doses in the range from 1-10 rad were equivalent to x-ray rupture doses of 3,500 rad. This report demonstrates that the experimental results are convincingly explained by reference to the properly calculated time-averaged dissipated power due to beta decay. The theoretical explanation is derived by analogy to a well-understood result from electronic systems known as shot noise. If the result described in this report is demonstrated to extrapolate from the benchtop to living systems, then it is likely that exposure to beta radiation via internal incorporation is far more hazardous than commonly believed. The finding could be revolutionary in the field of health physics.


Assuntos
Membranas/fisiologia , Modelos Teóricos , Fosfolipídeos/química , Radiometria/instrumentação , Radioisótopos de Sódio/efeitos adversos , Relação Dose-Resposta à Radiação , Humanos , Membranas/efeitos da radiação , Razão Sinal-Ruído , Raios X
5.
Res Vet Sci ; 124: 321-327, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31035220

RESUMO

Enterotoxigenic Escherichia coli (ETEC) is a worrying cause of diarrhoea in calves and the drug multiresistance phenotype concerning various antibiotic families are of concern. Resistance mechanisms associated with envelope changes (porin expression, efflux pump overexpression, lipolysaccahride (LPS) modification) were studied in 14 ETEC isolates selected for their resistance. We performed determinations of (i) antimicrobials Minimal Inhibitory Concentrations with or without the efflux pump inhibitor phenylalanine arginine ß-naphthylamide; (ii) colistin and polymyxin MICs with and without EDTA, (iii) intracellular accumulation of chloramphenicol in presence of an energy uncoupler of pump energy, (iv) and immunodetection of porins and evaluation of porin trimers thermostability. Results indicated that 9 strains presented significant efflux mechanisms overexpression, among them 8 were resistant to colistin and polymyxin B due to a modification of LPS structure as evidenced by EDTA effect and silver staining electrophoresis. The high resistant strains to colistin and polymyxin exhibited identical LPS patterns. Studies of E. coli porins indicated that the majority of strains didn't show modification in their amount, however analysis of porin thermostability showed that porin trimers of some resistant strains were relatively heat-labile, suggesting a misassembly of the functional trimer. The multidrug resistance (MDR) phenotypes detected in these selected ETEC corresponded to association of LPS modifications, abordive assembly of porin trimers and active efflux which drastically alter the antibiotic activity currently used to combat enteric infections caused by this pathogen.


Assuntos
Antibacterianos/farmacologia , Doenças dos Bovinos/microbiologia , Diarreia/veterinária , Farmacorresistência Bacteriana Múltipla , Escherichia coli Enterotoxigênica/efeitos dos fármacos , Infecções por Escherichia coli/veterinária , Lipopolissacarídeos/metabolismo , Animais , Bovinos , Cloranfenicol/farmacologia , Indústria de Laticínios , Diarreia/microbiologia , Escherichia coli Enterotoxigênica/fisiologia , Infecções por Escherichia coli/microbiologia , Fluoroquinolonas/farmacologia , Membranas/efeitos dos fármacos , Membranas/fisiologia , Testes de Sensibilidade Microbiana , Permeabilidade , Polimixinas/farmacologia
6.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1864(6): 763-765, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30769093

RESUMO

The phospholipase A2 (PLA2) family comprises a group of lipolytic enzymes that typically hydrolyze the sn-2 position of (glycerol) phospholipids to give rise to fatty acids and lysophospholipids. The mammalian genome encodes more than 30 (even 50) PLA2s or related enzymes, which are classified into several subfamilies on the basis of their structures and functions. The PLA2 family has been implicated not only in signal transduction by producing lipid mediators, but also in membrane homeostasis, energy production, and barrier function. Disturbance of PLA2-regulated lipid pathways often hampers tissue and cellular homeostasis and can be linked to various diseases. This special issue overviews the current state of understanding of the classification, enzymatic properties, and physiological functions of various enzymes belonging to the PLA2 family. This article is part of a Special Issue entitled Novel functions of phospholipase A2 Guest Editors: Makoto Murakami and Gerard Lambeau.


Assuntos
Fosfolipases A2/metabolismo , Animais , Humanos , Lipídeos/fisiologia , Membranas/metabolismo , Membranas/fisiologia , Transdução de Sinais/fisiologia
7.
Bioinspir Biomim ; 14(2): 026001, 2019 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-30608055

RESUMO

We examined the form-function relationship of laboratory-constructed artificial lateral line canals. These biomimetic flow sensors consisted of a transparent silicone bar located inside a fluid filled canal equipped with canal pores. The silicone bar guided the light from a LED towards a position- sensitive photodiode. Fluid motion inside the canal deflected the silicone bar which was detected by the photodiode. We found that the resonance frequency of the silicone bar determined the resonance frequency of the artificial lateral line (frequency at which the sensor was most sensitive). The thickness and length of the silicone bar influenced both, the resonance frequency and the sensitivity (across all tested frequencies) of the artificial lateral line sensor. Sensitivity was also influenced by the length and diameter of the artificial lateral line canals. The distance between canal pores determined the spatial resolution of the sensor. The functionality of the sensor in detecting oscillatory fluid motions remained when the canal pores were covered with flexible membranes. Tension, diameter and thickness of the membranes altered the temporal filter properties of the artificial lateral line neuromast. The density and viscosity of the fluid inside the artificial lateral line canals also influenced the sensitivity and temporal filter properties of the artificial lateral line. The acquired knowledge will allow us to optimize artificial lateral line systems for specific technical applications.


Assuntos
Sistema da Linha Lateral/fisiologia , Animais , Biomimética/métodos , Mecanorreceptores/fisiologia , Membranas/fisiologia , Movimento (Física) , Silicones/química
9.
BMC Biol ; 16(1): 119, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30382870

RESUMO

Joel Dacks is an Associate Professor and Canada Research Chair in Evolutionary Cell Biology at the University of Alberta, a Scientific Associate at the Natural History Museum (London), and the current President of the International Society for Evolutionary Protistology. His research group studies the evolution and diversity of the eukaryotic membrane-trafficking system, from origins to potential disease therapeutics. In this interview, Joel shares some perspectives on gaining a balanced view of comparative cell biology and the importance of a constructive peer review process.


Assuntos
Transporte Biológico/fisiologia , Biologia Celular/história , Membranas/fisiologia , Alberta , Eucariotos/fisiologia , História do Século XXI , Londres , Revisão da Pesquisa por Pares
10.
J Chem Phys ; 148(12): 123318, 2018 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-29604873

RESUMO

Kinesin-1 (hereafter referred to as kinesin) is a major microtubule-based motor protein for plus-end-directed intracellular transport in live cells. While the single-molecule functions of kinesin are well characterized, the physiologically relevant transport of membranous cargos by small teams of kinesins remains poorly understood. A key experimental challenge remains in the quantitative control of the number of motors driving transport. Here we utilized "motile fraction" to overcome this challenge and experimentally accessed transport by a single kinesin through the physiologically relevant transport by a small team of kinesins. We used a fluid lipid bilayer to model the cellular membrane in vitro and employed optical trapping to quantify the transport of membrane-enclosed cargos versus traditional membrane-free cargos under identical conditions. We found that coupling motors via a fluid membrane significantly enhances the velocity of cargo transport by small teams of kinesins. Importantly, enclosing a cargo in a fluid lipid membrane did not impact single-kinesin transport, indicating that membrane-dependent velocity enhancement for team-based transport arises from altered interactions between kinesins. Our study demonstrates that membrane-based coupling between motors is a key determinant of kinesin-based transport. Enhanced velocity may be critical for fast delivery of cargos in live cells.


Assuntos
Cinesina/química , Membranas/química , Modelos Biológicos , Transporte Biológico , Hidrodinâmica , Cinesina/fisiologia , Membranas/fisiologia
11.
Biochim Biophys Acta Biomembr ; 1860(10): 1972-1984, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29505769

RESUMO

Demixing of components has long been described in model membranes. It is a consequence of non-ideal lateral interactions between membrane components, and it causes the presence of segregated phases, forming patches (domains) of different properties, thus introducing heterogeneity into the membrane. In the present review we first describe the processes through which domains are generated, how they grow, and why they are rounded, striped or fractal-like, as well as why they get distributed forming defined patterns. Next, we focus on the effect of an additive on a lipid mixture, which usually induces shifts in demixing points, thus stabilizing or destabilizing the phase-segregated state. Results found for different model membranes are summarized, detailing the ways in which phase segregation and the generated patterns may be modulated. We focus on which are, from our viewpoint, the most relevant regulating factors affecting the surface texture observed in model membranes. This article is part of a Special Issue entitled: Emergence of Complex Behavior in Biomembranes edited by Marjorie Longo.


Assuntos
Bicamadas Lipídicas/química , Lipídeos de Membrana/química , Membranas/química , Membrana Celular/química , Lipídeos/química , Proteínas de Membrana/química , Membranas/fisiologia , Modelos Biológicos , Transição de Fase
13.
Biochim Biophys Acta Biomembr ; 1860(5): 1114-1124, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29317198

RESUMO

Particularly in Asia medicinal plants with antimicrobial activity are used for therapeutic purpose. One such plant-derived antibiotic is rhodomyrtone (Rom) isolated from Rhodomyrtus tomentosa leaves. Rom shows high antibacterial activity against a wide range of Gram-positive bacteria, however, its mode of action is still unclear. Reporter gene assays and proteomic profiling experiments in Bacillus subtilis indicate that Rom does not address classical antibiotic targets like translation, transcription or DNA replication, but acts at the cytoplasmic membrane. In Staphylococcus aureus, Rom decreases the membrane potential within seconds and at low doses, causes release of ATP and even the excretion of cytoplasmic proteins (ECP), but does not induce pore-formation as for example nisin. Lipid staining revealed that Rom induces local membrane damage. Rom's antimicrobial activity can be antagonized in the presence of a very narrow spectrum of saturated fatty acids (C15:0, C16:0, or C18:0) that most likely contribute to counteract the membrane damage. Gram-negative bacteria are resistant to Rom, presumably due to reduced penetration through the outer membrane and its neutralization by LPS. Rom is cytotoxic for many eukaryotic cells and studies with human erythrocytes showed that Rom induces eryptosis accompanied by erythrocyte shrinkage, cell membrane blebbing, and membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Rom's distinctive interaction with the cytoplasmic membrane reminds on the amphipathic, alpha-helical peptides, the phenol-soluble modulins (PSMs), and renders Rom an important tool for the investigation of membrane physiology.


Assuntos
Anti-Infecciosos/farmacologia , Membranas/efeitos dos fármacos , Xantonas/farmacologia , Animais , Células 3T3 BALB , Bacillus subtilis , Células Cultivadas , Células HeLa , Hemólise/efeitos dos fármacos , Humanos , Potenciais da Membrana/efeitos dos fármacos , Membranas/fisiologia , Camundongos , Testes de Sensibilidade Microbiana , Staphylococcus aureus
14.
J Vis Exp ; (128)2017 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-28994799

RESUMO

Multicellular tubes, fundamental units of all internal organs, are composed of polarized epithelial or endothelial cells, with apical membranes lining the lumen and basolateral membranes contacting each other and/or the extracellular matrix. How this distinctive membrane asymmetry is established and maintained during organ morphogenesis is still an unresolved question of cell biology. This protocol describes the C. elegans intestine as a model for the analysis of polarized membrane biogenesis during tube morphogenesis, with emphasis on apical membrane and lumen biogenesis. The C. elegans twenty-cell single-layered intestinal epithelium is arranged into a simple bilaterally symmetrical tube, permitting analysis on a single-cell level. Membrane polarization occurs concomitantly with polarized cell division and migration during early embryogenesis, but de novo polarized membrane biogenesis continues throughout larval growth, when cells no longer proliferate and move. The latter setting allows one to separate subcellular changes that simultaneously mediate these different polarizing processes, difficult to distinguish in most polarity models. Apical-, basolateral membrane-, junctional-, cytoskeletal- and endomembrane components can be labeled and tracked throughout development by GFP fusion proteins, or assessed by in situ antibody staining. Together with the organism's genetic versatility, the C. elegans intestine thus provides a unique in vivo model for the visual, developmental, and molecular genetic analysis of polarized membrane and tube biogenesis. The specific methods (all standard) described here include how to: label intestinal subcellular components by antibody staining; analyze genes involved in polarized membrane biogenesis by loss-of-function studies adapted to the typically essential tubulogenesis genes; assess polarity defects during different developmental stages; interpret phenotypes by epifluorescence, differential interference contrast (DIC) and confocal microscopy; quantify visual defects. This protocol can be adapted to analyze any of the often highly conserved molecules involved in epithelial polarity, membrane biogenesis, tube and lumen morphogenesis.


Assuntos
Caenorhabditis elegans/anatomia & histologia , Caenorhabditis elegans/fisiologia , Intestinos/anatomia & histologia , Intestinos/fisiologia , Morfogênese/fisiologia , Biogênese de Organelas , Interferência de RNA/fisiologia , Animais , Anticorpos/química , Caenorhabditis elegans/crescimento & desenvolvimento , Intestinos/diagnóstico por imagem , Membranas/anatomia & histologia , Membranas/crescimento & desenvolvimento , Membranas/fisiologia , Coloração e Rotulagem/métodos
16.
Hand Surg Rehabil ; 36(5): 314-321, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28751170

RESUMO

Distal radioulnar joint (DRUJ) instabilities are common and often combined with other injuries of the interosseous membrane and/or the proximal radioulnar joint. Once they are diagnosed and the treatment is chosen, physiotherapists have limited choices due to the lack of validated protocols. The benefits of proprioception and neuromuscular rehabilitation have been brought to light for the shoulder, knee and ankle joints, among others. However, no program has been described for the DRUJ. The purpose of this article is to study the muscular elements responsible for active DRUJ stability, and to propose a proprioceptive rehabilitation program suited to this condition.


Assuntos
Instabilidade Articular/reabilitação , Modalidades de Fisioterapia , Articulação do Punho/fisiopatologia , Braquetes , Humanos , Instabilidade Articular/fisiopatologia , Ligamentos Articulares/anatomia & histologia , Ligamentos Articulares/fisiologia , Membranas/anatomia & histologia , Membranas/fisiologia , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/fisiologia , Fibrocartilagem Triangular/anatomia & histologia , Fibrocartilagem Triangular/fisiologia , Articulação do Punho/anatomia & histologia
17.
Mol Biol Cell ; 28(1): 152-160, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-28035046

RESUMO

Classical dynamins bind the plasma membrane-localized phosphatidylinositol-4,5-bisphosphate using the pleckstrin-homology domain (PHD) and engage in rapid membrane fission during synaptic vesicle recycling. This domain is conspicuously absent among extant bacterial and mitochondrial dynamins, however, where loop regions manage membrane recruitment. Inspired by the core design of bacterial and mitochondrial dynamins, we reengineered the classical dynamin by replacing its PHD with a polyhistidine or polylysine linker. Remarkably, when recruited via chelator or anionic lipids, respectively, the reengineered dynamin displayed the capacity to constrict and sever membrane tubes. However, when analyzed at single-event resolution, the tube-severing process displayed long-lived, highly constricted prefission intermediates that contributed to 10-fold reduction in bulk rates of membrane fission. Our results indicate that the PHD acts as a catalyst in dynamin-induced membrane fission and rationalize its adoption to meet the physiologic requirement of a fast-acting membrane fission apparatus.


Assuntos
Dinaminas/metabolismo , Dinaminas/ultraestrutura , Dinâmica Mitocondrial/fisiologia , Membrana Celular/metabolismo , Constrição , Dinaminas/genética , Endocitose/fisiologia , GTP Fosfo-Hidrolases/metabolismo , Guanosina Trifosfato/metabolismo , Humanos , Membranas/metabolismo , Membranas/fisiologia , Mitocôndrias/metabolismo , Dinâmica Mitocondrial/genética , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatidilinositóis/metabolismo , Domínios de Homologia à Plecstrina/genética , Domínios de Homologia à Plecstrina/fisiologia , Domínios Proteicos , Estrutura Terciária de Proteína
18.
J Cell Sci ; 130(17): 2775-2779, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29360626

RESUMO

The first ever 'Cellular Dynamics' meeting on the membrane-cytoskeleton interface took place in Southbridge, MA on May 21-24, 2017 and was co-organized by Michael Way, Elizabeth Chen, Margaret Gardel and Jennifer Lippincott-Schwarz. Investigators from around the world studying a broad range of related topics shared their insights into the function and regulation of the cytoskeleton and membrane compartments. This provided great opportunities to learn about key questions in various cellular processes, from the basic organization and operation of the cell to higher-order interactions in adhesion, migration, metastasis, division and immune cell interactions in different model organisms. This unique and diverse mix of research interests created a stimulating and educational meeting that will hopefully continue to be a successful meeting for years to come.


Assuntos
Fenômenos Fisiológicos Celulares/fisiologia , Congressos como Assunto , Citoesqueleto/fisiologia , Humanos , Membranas/fisiologia
19.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1862(2): 156-166, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27815222

RESUMO

Neurospora crassa, a filamentous fungus, in the unicellular conidial stage has ideal features to study sphingolipid (SL)-enriched domains, which are implicated in fundamental cellular processes ranging from antifungal resistance to apoptosis. Several changes in lipid metabolism and in the membrane composition of N. crassa occur during spore germination. However, the biophysical impact of those changes is unknown. Thus, a biophysical study of N. crassa plasma membrane, particularly SL-enriched domains, and their dynamics along conidial germination is prompted. Two N. crassa strains, wild-type (WT) and slime, which is devoid of cell wall, were studied. Conidial growth of N. crassa WT from a dormancy state to an exponential phase was accompanied by membrane reorganization, namely an increase of membrane fluidity, occurring faster in a supplemented medium than in Vogel's minimal medium. Gel-like domains, likely enriched in SLs, were found in both N. crassa strains, but were particularly compact, rigid and abundant in the case of slime cells, even more than in budding yeast Saccharomyces cerevisiae. In N. crassa, our results suggest that the melting of SL-enriched domains occurs near growth temperature (30°C) for WT, but at higher temperatures for slime. Regarding biophysical properties strongly affected by ergosterol, the plasma membrane of slime conidia lays in between those of N. crassa WT and S. cerevisiae cells. The differences in biophysical properties found in this work, and the relationships established between membrane lipid composition and dynamics, give new insights about the plasma membrane organization and structure of N. crassa strains during conidial growth.


Assuntos
Membrana Celular/metabolismo , Membrana Celular/fisiologia , Lipídeos de Membrana/metabolismo , Neurospora crassa/crescimento & desenvolvimento , Neurospora crassa/metabolismo , Esfingolipídeos/metabolismo , Esporos/metabolismo , Parede Celular/metabolismo , Parede Celular/fisiologia , Proteínas Fúngicas/metabolismo , Fluidez de Membrana/fisiologia , Membranas/metabolismo , Membranas/fisiologia , Neurospora crassa/fisiologia , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiologia , Esporos/crescimento & desenvolvimento , Esporos/fisiologia , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo , Esporos Fúngicos/fisiologia
20.
J Mol Evol ; 83(5-6): 159-168, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27913841

RESUMO

Cells are the units of all life today, and are defined by their membranous boundaries. The membranes have multiple functions; the most obvious being that, in the absence of a boundary, the systems of functional macromolecular components of the cytosol would spill into the environment and disperse. Membranes also contain the pigments essential for photosynthesis, electron transport enzymes that pump and maintain proton gradients, the ATP synthase that uses proton gradients to produce energy for the cell, and enzymes that use ATP to maintain ion gradients essential for life. But what about the function of membranes in the first forms of cellular life? Could life have begun in the absence of membranous boundaries? In order to answer that question, this review presents a history of the key research observations that began over a century ago.


Assuntos
Membranas/anatomia & histologia , Membranas/metabolismo , Membranas/fisiologia , Transporte de Elétrons , Origem da Vida , Fotossíntese , Prótons , Tensoativos
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