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Hoh D, Froehlich JE, Kramer DM. Redox regulation in chloroplast thylakoid lumen: The pmf changes everything, again. PLANT, CELL & ENVIRONMENT 2024; 47:2749-2765. [PMID: 38111217 DOI: 10.1111/pce.14789] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/28/2023] [Accepted: 12/05/2023] [Indexed: 12/20/2023]
Abstract
Photosynthesis is the foundation of life on Earth. However, if not well regulated, it can also generate excessive reactive oxygen species (ROS), which can cause photodamage. Regulation of photosynthesis is highly dynamic, responding to both environmental and metabolic cues, and occurs at many levels, from light capture to energy storage and metabolic processes. One general mechanism of regulation involves the reversible oxidation and reduction of protein thiol groups, which can affect the activity of enzymes and the stability of proteins. Such redox regulation has been well studied in stromal enzymes, but more recently, evidence has emerged of redox control of thylakoid lumenal enzymes. This review/hypothesis paper summarizes the latest research and discusses several open questions and challenges to achieving effective redox control in the lumen, focusing on the distinct environments and regulatory components of the thylakoid lumen, including the need to transport electrons across the thylakoid membrane, the effects of pH changes by the proton motive force (pmf) in the stromal and lumenal compartments, and the observed differences in redox states. These constraints suggest that activated oxygen species are likely to be major regulatory contributors to lumenal thiol redox regulation, with key components and processes yet to be discovered.
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Affiliation(s)
- Donghee Hoh
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
| | - John E Froehlich
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - David M Kramer
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
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Grebe S, Porcar-Castell A, Riikonen A, Paakkarinen V, Aro EM. Accounting for photosystem I photoinhibition sheds new light on seasonal acclimation strategies of boreal conifers. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3973-3992. [PMID: 38572950 PMCID: PMC11233416 DOI: 10.1093/jxb/erae145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Accepted: 05/30/2024] [Indexed: 04/05/2024]
Abstract
The photosynthetic acclimation of boreal evergreen conifers is controlled by regulatory and photoprotective mechanisms that allow conifers to cope with extreme environmental changes. However, the underlying dynamics of photosystem II (PSII) and photosystem I (PSI) remain unresolved. Here, we investigated the dynamics of PSII and PSI during the spring recovery of photosynthesis in Pinus sylvestris and Picea abies using a combination of chlorophyll a fluorescence, P700 difference absorbance measurements, and quantification of key thylakoid protein abundances. In particular, we derived a new set of PSI quantum yield equations, correcting for the effects of PSI photoinhibition. Using the corrected equations, we found that the seasonal dynamics of PSII and PSI photochemical yields remained largely in balance, despite substantial seasonal changes in the stoichiometry of PSII and PSI core complexes driven by PSI photoinhibition. Similarly, the previously reported seasonal up-regulation of cyclic electron flow was no longer evident, after accounting for PSI photoinhibition. Overall, our results emphasize the importance of considering the dynamics of PSII and PSI to elucidate the seasonal acclimation of photosynthesis in overwintering evergreens. Beyond the scope of conifers, our corrected PSI quantum yields expand the toolkit for future studies aimed at elucidating the dynamic regulation of PSI.
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Affiliation(s)
- Steffen Grebe
- Molecular Plant Biology, Department of Life Technologies, University of Turku, 20014 Turku, Finland
- Optics of Photosynthesis Laboratory, Viikki Plant Science Center, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Albert Porcar-Castell
- Optics of Photosynthesis Laboratory, Viikki Plant Science Center, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Anu Riikonen
- Optics of Photosynthesis Laboratory, Viikki Plant Science Center, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Virpi Paakkarinen
- Molecular Plant Biology, Department of Life Technologies, University of Turku, 20014 Turku, Finland
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Life Technologies, University of Turku, 20014 Turku, Finland
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3
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Tikhonov AN. Electron Transport in Chloroplasts: Regulation and Alternative Pathways of Electron Transfer. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1438-1454. [PMID: 38105016 DOI: 10.1134/s0006297923100036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/09/2023] [Accepted: 07/09/2023] [Indexed: 12/19/2023]
Abstract
This work represents an overview of electron transport regulation in chloroplasts as considered in the context of structure-function organization of photosynthetic apparatus in plants. Main focus of the article is on bifurcated oxidation of plastoquinol by the cytochrome b6f complex, which represents the rate-limiting step of electron transfer between photosystems II and I. Electron transport along the chains of non-cyclic, cyclic, and pseudocyclic electron flow, their relationships to generation of the trans-thylakoid difference in electrochemical potentials of protons in chloroplasts, and pH-dependent mechanisms of regulation of the cytochrome b6f complex are considered. Redox reactions with participation of molecular oxygen and ascorbate, alternative mediators of electron transport in chloroplasts, have also been discussed.
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Subczynski WK, Widomska J, Raguz M, Pasenkiewicz-Gierula M. Molecular oxygen as a probe molecule in EPR spin-labeling studies of membrane structure and dynamics. OXYGEN (BASEL, SWITZERLAND) 2022; 2:295-316. [PMID: 36852103 PMCID: PMC9965258 DOI: 10.3390/oxygen2030021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Molecular oxygen (O2) is the perfect probe molecule for membrane studies carried out using the saturation recovery EPR technique. O2 is a small, paramagnetic, hydrophobic enough molecule that easily partitions into a membrane's different phases and domains. In membrane studies, the saturation recovery EPR method requires two paramagnetic probes: a lipid-analog nitroxide spin label and an oxygen molecule. The experimentally derived parameters of this method are the spin-lattice relaxation times (T 1s) of spin labels and rates of bimolecular collisions between O2 and the nitroxide fragment. Thanks to the long T 1 of lipid spin labels (from 1 to 10 μs), the approach is very sensitive to changes of the local (around the nitroxide fragment) O2 diffusion-concentration product. Small variations in the lipid packing affect O2 solubility and O2 diffusion, which can be detected by the shortening of T 1 of spin labels. Using O2 as a probe molecule and a different lipid spin label inserted into specific phases of the membrane and membrane domains allows data about the lateral arrangement of lipid membranes to be obtained. Moreover, using a lipid spin label with the nitroxide fragment attached to its head group or a hydrocarbon chain at different positions also enables data about molecular dynamics and structure at different membrane depths to be obtained. Thus, the method can be used to investigate not only the lateral organization of the membrane (i.e., the presence of membrane domains and phases), but also the depth-dependent membrane structure and dynamics, and, hence, the membrane properties in three dimensions.
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Affiliation(s)
- Witold K. Subczynski
- Department of Biophysics, Medical College on Wisconsin, Milwaukee, United States
| | - Justyna Widomska
- Department of Biophysics, Medical University of Lublin, Lublin, Poland
| | - Marija Raguz
- Department of Medical Physics and Biophysics, University of Split School of Medicine, Split, Croatia
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Chautrand T, Souak D, Chevalier S, Duclairoir-Poc C. Gram-Negative Bacterial Envelope Homeostasis under Oxidative and Nitrosative Stress. Microorganisms 2022; 10:924. [PMID: 35630368 PMCID: PMC9144841 DOI: 10.3390/microorganisms10050924] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 04/15/2022] [Accepted: 04/21/2022] [Indexed: 12/15/2022] Open
Abstract
Bacteria are frequently exposed to endogenous and exogenous reactive oxygen and nitrogen species which can damage various biomolecules such as DNA, lipids, and proteins. High concentrations of these molecules can induce oxidative and nitrosative stresses in the cell. Reactive oxygen and nitrogen species are notably used as a tool by prokaryotes and eukaryotes to eradicate concurrent species or to protect themselves against pathogens. The main example is mammalian macrophages that liberate high quantities of reactive species to kill internalized bacterial pathogens. As a result, resistance to these stresses is determinant for the survival of bacteria, both in the environment and in a host. The first bacterial component in contact with exogenous molecules is the envelope. In Gram-negative bacteria, this envelope is composed of two membranes and a layer of peptidoglycan lodged between them. Several mechanisms protecting against oxidative and nitrosative stresses are present in the envelope, highlighting the importance for the cell to deal with reactive species in this compartment. This review aims to provide a comprehensive view of the challenges posed by oxidative and nitrosative stresses to the Gram-negative bacterial envelope and the mechanisms put in place in this compartment to prevent and repair the damages they can cause.
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Affiliation(s)
| | | | | | - Cécile Duclairoir-Poc
- Research Unit Bacterial Communication and Anti-infectious Strategies (UR CBSA), Rouen Normandy University, Normandy University, 55 rue Saint-Germain, 27000 Evreux, France; (T.C.); (D.S.); (S.C.)
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6
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When anaerobes encounter oxygen: mechanisms of oxygen toxicity, tolerance and defence. Nat Rev Microbiol 2021; 19:774-785. [PMID: 34183820 PMCID: PMC9191689 DOI: 10.1038/s41579-021-00583-y] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2021] [Indexed: 02/06/2023]
Abstract
The defining trait of obligate anaerobes is that oxygen blocks their growth, yet the underlying mechanisms are unclear. A popular hypothesis was that these microorganisms failed to evolve defences to protect themselves from reactive oxygen species (ROS) such as superoxide and hydrogen peroxide, and that this failure is what prevents their expansion to oxic habitats. However, studies reveal that anaerobes actually wield most of the same defences that aerobes possess, and many of them have the capacity to tolerate substantial levels of oxygen. Therefore, to understand the structures and real-world dynamics of microbial communities, investigators have examined how anaerobes such as Bacteroides, Desulfovibrio, Pyrococcus and Clostridium spp. struggle and cope with oxygen. The hypoxic environments in which these organisms dwell - including the mammalian gut, sulfur vents and deep sediments - experience episodic oxygenation. In this Review, we explore the molecular mechanisms by which oxygen impairs anaerobes and the degree to which bacteria protect their metabolic pathways from it. The emergent view of anaerobiosis is that optimal strategies of anaerobic metabolism depend upon radical chemistry and low-potential metal centres. Such catalytic sites are intrinsically vulnerable to direct poisoning by molecular oxygen and ROS. Observations suggest that anaerobes have evolved tactics that either minimize the extent to which oxygen disrupts their metabolism or restore function shortly after the stress has dissipated.
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Agostini A, Bortolus M, Ferlez B, Walters K, Golbeck JH, van der Est A, Carbonera D. Differential sensitivity to oxygen among the bacteriochlorophylls g in the type-I reaction centers of Heliobacterium modesticaldum. Photochem Photobiol Sci 2021; 20:747-759. [PMID: 34018156 DOI: 10.1007/s43630-021-00049-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/28/2021] [Indexed: 11/27/2022]
Abstract
The type-I, homodimeric photosynthetic reaction center (RC) of Heliobacteria (HbRC) is the only known RC in which bacteriochlorophyll g (BChl g) is found. It is also simpler than other RCs, having the smallest number of protein subunits and bound chromophores of any type-I RC. In the presence of oxygen, BChl g isomerizes to 81-hydroxychlorophyll aF (Chl aF). This naturally occurring process provides a way of altering the chlorophylls and studying the effect of these changes on energy and electron transfer. Transient absorbance difference spectroscopy reveals that triplet-state formation occurs in the antenna chlorophylls of HbRCs but does not provide site-specific information. Here, we report on an extended optically detected magnetic resonance (ODMR) study of the antenna triplet states in HbRCs with differing levels of conversion of BChl g to Chl aF. The data reveal pools of BChl g molecules with different triplet zero-field splitting parameters and different susceptibilities to chemical oxidation. By relating the detailed spectroscopic characteristics derived from the ODMR data to the recently solved crystallographic structure, we have tentatively identified BChl g molecules in which the probability of triplet formation is high and sites at which BChl g conversion is more likely, providing useful information about the fate of the excitation in the complex.
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Affiliation(s)
- Alessandro Agostini
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131, Padua, Italy.,Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branisovska 31, 37005, České Budějovice, Czechia
| | - Marco Bortolus
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131, Padua, Italy
| | - Bryan Ferlez
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.,Department of Biochemistry and Molecular Biology and MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
| | - Karim Walters
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Art van der Est
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock, Way, Saint Catharines, ON, L2S 3A1, Canada.
| | - Donatella Carbonera
- Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131, Padua, Italy.
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Vershubskii AV, Tikhonov AN. Structural and Functional Aspects of Electron Transport Thermoregulation and ATP Synthesis in Chloroplasts. BIOCHEMISTRY (MOSCOW) 2021; 86:92-104. [PMID: 33705285 DOI: 10.1134/s0006297921010090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The review is focused on analysis of the mechanisms of temperature-dependent regulation of electron transport and ATP synthesis in chloroplasts of higher plants. Importance of photosynthesis thermoregulation is determined by the fact that plants are ectothermic organisms, whose own temperature depends on the ambient temperature. The review discusses the effects of temperature on the following processes in thylakoid membranes: (i) photosystem 2 activity and plastoquinone reduction; (ii) electron transfer from plastoquinol (via the cytochrome b6f complex and plastocyanin) to photosystem 1; (iii) transmembrane proton transfer; and (iv) ATP synthesis. The data on the relationship between the functional properties of chloroplasts (photosynthetic transfer of electrons and protons, functioning of ATP synthase) and structural characteristics of membrane lipids (fluidity) obtained by electron paramagnetic resonance studies are presented.
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9
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Nami F, Tian L, Huber M, Croce R, Pandit A. Lipid and protein dynamics of stacked and cation-depletion induced unstacked thylakoid membranes. BBA ADVANCES 2021; 1:100015. [PMID: 37082020 PMCID: PMC10074959 DOI: 10.1016/j.bbadva.2021.100015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Chloroplast thylakoid membranes in plants and green algae form 3D architectures of stacked granal membranes interconnected by unstacked stroma lamellae. They undergo dynamic structural changes as a response to changing light conditions that involve grana unstacking and lateral supramolecular reorganization of the integral membrane protein complexes. We assessed the dynamics of thylakoid membrane components and addressed how they are affected by thylakoid unstacking, which has consequences for protein mobility and the diffusion of small electron carriers. By a combined nuclear and electron paramagnetic-resonance approach the dynamics of thylakoid lipids was assessed in stacked and cation-depletion induced unstacked thylakoids of Chlamydomonas (C.) reinhardtii. We could distinguish between structural, bulk and annular lipids and determine membrane fluidity at two membrane depths: close to the lipid headgroups and in the lipid bilayer center. Thylakoid unstacking significantly increased the dynamics of bulk and annular lipids in both areas and increased the dynamics of protein helices. The unstacking process was associated with membrane reorganization and loss of long-range ordered Photosystem II- Light-Harvesting Complex II (PSII-LHCII) complexes. The fluorescence lifetime characteristics associated with membrane unstacking are similar to those associated with state transitions in intact C. reinhardtii cells. Our findings could be relevant for understanding the structural and functional implications of thylakoid unstacking that is suggested to take place during several light-induced processes, such as state transitions, photoacclimation, photoinhibition and PSII repair.
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Affiliation(s)
- Faezeh Nami
- Institute of Chemistry, Leiden University, 2333 CC, Leiden, The Netherlands
| | - Lijin Tian
- Institute of Chemistry, Leiden University, 2333 CC, Leiden, The Netherlands
| | - Martina Huber
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, 2300 RA, Leiden, The Netherlands
| | - Roberta Croce
- Department of Physics and Astronomy, VU University Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Anjali Pandit
- Institute of Chemistry, Leiden University, 2333 CC, Leiden, The Netherlands
- Corresponding author:
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10
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Tikhonov AN, Vershubskii AV. Temperature-dependent regulation of electron transport and ATP synthesis in chloroplasts in vitro and in silico. PHOTOSYNTHESIS RESEARCH 2020; 146:299-329. [PMID: 32780309 DOI: 10.1007/s11120-020-00777-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
The significance of temperature-dependent regulation of photosynthetic apparatus (PSA) is determined by the fact that plant temperature changes with environmental temperature. In this work, we present a brief overview of temperature-dependent regulation of photosynthetic processes in class B chloroplasts (thylakoids) and analyze these processes using a computer model that takes into account the key stages of electron and proton transport coupled to ATP synthesis. The rate constants of partial reactions were parametrized on the basis of experimental temperature dependences of partial photosynthetic processes: (1) photosystem II (PSII) turnover and plastoquinone (PQ) reduction, (2) the plastoquinol (PQH2) oxidation by the cytochrome (Cyt) b6f complex, (3) the ATP synthase activity, and (4) the proton leak from the thylakoid lumen. We consider that PQH2 oxidation is the rate-limiting step in the intersystem electron transport. The parametrization of the rate constants of these processes is based on earlier experimental data demonstrating strong correlations between the functional and structural properties of thylakoid membranes that were probed with the lipid-soluble spin labels embedded into the membranes. Within the framework of our model, we could adequately describe a number of experimental temperature dependences of photosynthetic reactions in thylakoids. Computer modeling of electron and proton transport coupled to ATP synthesis supports the notion that PQH2 oxidation by the Cyt b6f complex and proton pumping into the lumen are the basic temperature-dependent processes that determine the overall electron flux from PSII to molecular oxygen and the net ATP synthesis upon variations of temperature. The model describes two branches of the temperature dependence of the post-illumination reduction of [Formula: see text] characterized by different activation energies (about 60 and ≤ 3.5 kJ mol-1). The model predicts the bell-like temperature dependence of ATP formation, which arises from the balance of several factors: (1) the thermo-induced acceleration of electron transport through the Cyt b6f complex, (2) deactivation of PSII photochemistry at sufficiently high temperatures, and (3) acceleration of the passive proton outflow from the thylakoid lumen bypassing the ATP synthase complex. The model describes the temperature dependence of experimentally measured parameter P/2e, determined as the ratio between the rates of ATP synthesis and pseudocyclic electron transport (H2O → PSII → PSI → O2).
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Affiliation(s)
- Alexander N Tikhonov
- Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russia.
- N.M. Emanuel Institute of Biochemical Physics of Russian Academy of Sciences, Moscow, Russia.
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Shimizu K, Matsuoka Y. Redox rebalance against genetic perturbations and modulation of central carbon metabolism by the oxidative stress regulation. Biotechnol Adv 2019; 37:107441. [PMID: 31472206 DOI: 10.1016/j.biotechadv.2019.107441] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 08/04/2019] [Accepted: 08/23/2019] [Indexed: 12/11/2022]
Abstract
The micro-aerophilic organisms and aerobes as well as yeast and higher organisms have evolved to gain energy through respiration (via oxidative phosphorylation), thereby enabling them to grow much faster than anaerobes. However, during respiration, reactive oxygen species (ROSs) are inherently (inevitably) generated, and threaten the cell's survival. Therefore, living organisms (or cells) must furnish the potent defense systems to keep such ROSs at harmless level, where the cofactor balance plays crucial roles. Namely, NADH is the source of energy generation (catabolism) in the respiratory chain reactions, through which ROSs are generated, while NADPH plays important roles not only for the cell synthesis (anabolism) but also for detoxifying ROSs. Therefore, the cell must rebalance the redox ratio by modulating the fluxes of the central carbon metabolism (CCM) by regulating the multi-level regulation machinery upon genetic perturbations and the change in the growth conditions. Here, we discuss about how aerobes accomplish such cofactor homeostasis against redox perturbations. In particular, we consider how single-gene mutants (including pgi, pfk, zwf, gnd and pyk mutants) modulate their metabolisms in relation to cofactor rebalance (and also by adaptive laboratory evolution). We also discuss about how the overproduction of NADPH (by the pathway gene mutation) can be utilized for the efficient production of useful value-added chemicals such as medicinal compounds, polyhydroxyalkanoates, and amino acids, all of which require NADPH in their synthetic pathways. We then discuss about the metabolic responses against oxidative stress, where αketoacids play important roles not only for the coordination between catabolism and anabolism, but also for detoxifying ROSs by non-enzymatic reactions, as well as for reducing the production of ROSs by repressing the activities of the TCA cycle and respiration (via carbon catabolite repression). Thus, we discuss about the mechanisms (basic strategies) that modulate the metabolism from respiration to respiro-fermentative metabolism causing overflow, based on the role of Pyk activity, affecting the NADPH production at the oxidative pentose phosphate (PP) pathway, and the roles of αketoacids for the change in the source of energy generation from the oxidative phosphorylation to the substrate level phosphorylation.
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Affiliation(s)
- Kazuyuki Shimizu
- Kyushu institute of Technology, Iizuka, Fukuoka 820-8502, Japan; Institute of Advanced Biosciences, Keio university, Tsuruoka, Yamagata 997-0017, Japan.
| | - Yu Matsuoka
- Kyushu institute of Technology, Iizuka, Fukuoka 820-8502, Japan.
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12
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Lu Z, Imlay JA. A conserved motif liganding the [4Fe-4S] cluster in [4Fe-4S] fumarases prevents irreversible inactivation of the enzyme during hydrogen peroxide stress. Redox Biol 2019; 26:101296. [PMID: 31465957 PMCID: PMC6831887 DOI: 10.1016/j.redox.2019.101296] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 08/04/2019] [Accepted: 08/07/2019] [Indexed: 11/16/2022] Open
Abstract
Organisms have evolved two different classes of the ubiquitous enzyme fumarase: the [4Fe–4S] cluster-containing class I enzymes are oxidant-sensitive, whereas the class II enzymes are iron-free and therefore oxidant-resistant. When hydrogen peroxide (H2O2) attacks the most-studied [4Fe–4S] fumarases, only the cluster is damaged, and thus the cell can rapidly repair the enzyme. However, this study shows that when elevated levels of H2O2 oxidized the class I fumarase of the obligate anaerobe Bacteroides thetaiotaomicron (Bt-Fum), a hydroxyl-like radical species was produced that caused irreversible covalent damage to the polypeptide. Unlike the fumarase of oxygen-tolerant bacteria, Bt-Fum lacks a key cysteine residue in the typical “CXnCX2C″ motif that ligands [4Fe–4S] clusters. Consequently H2O2 can access and oxidize an iron atom other than the catalytic one in its cluster. Phylogenetic analysis showed that certain clades of bacteria may have evolved the full “CXnCX2C″ motif to shield the [4Fe–4S] cluster of fumarase. This effect was reproduced by the construction of a chimeric enzyme. These data demonstrate the irreversible oxidation of Fe–S cluster enzymes and may recapitulate evolutionary steps that occurred when microorganisms originally confronted oxidizing environments. It is also suggested that, if H2O2 is generated within the colon as a consequence of inflammation or the action of lactic acid bacteria, the inactivation of fumarase could potentially impair the central fermentation pathway of Bacteroides species and contribute to gut dysbiosis.
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Affiliation(s)
- Zheng Lu
- Department of Biology, Guangdong Provincial Key Laboratory of Marine Biotechnology, STU-UNIVPM Joint Algal Research Center, Shantou University, Shantou, 515063, China.
| | - James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave., Urbana, IL, 61801, USA
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Oxygenic photosynthesis: EPR study of photosynthetic electron transport and oxygen-exchange, an overview. Cell Biochem Biophys 2018; 77:47-59. [PMID: 30460441 DOI: 10.1007/s12013-018-0861-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 11/01/2018] [Indexed: 12/28/2022]
Abstract
In this review, we consider the applications of electron paramagnetic resonance (EPR) methods to the study of the relationships between the electron transport and oxygen-exchange processes in photosynthetic systems of oxygenic type. One of the purposes of this article is to encourage scientists to use the advantageous EPR oximetry approaches to study oxygen-related electron transport processes in photosynthetic systems. The structural organization of the photosynthetic electron transfer chain and the EPR approaches to the measurements of molecular oxygen (O2) with O2-sensitive species (nitroxide spin labels and solid paramagnetic particles) are briefly reviewed. In solution, the collision of O2 with spin probes causes the broadening of their EPR spectra and the reduction of their spin-lattice relaxation times. Based on these effects, tools for measuring O2 concentration and O2 diffusion in biological systems have been developed. These methods, named "spin-label oximetry," include not only nitroxide spin labels, but also other stable-free radicals with narrow EPR lines, as well as particulate probes with EPR spectra sensitive to molecular oxygen (lithium phthalocyanine, coals, and India ink). Applications of EPR approaches for measuring O2 evolution and consumption are illustrated using examples of photosynthetic systems of oxygenic type, chloroplasts in situ (green leaves), and cyanobacteria.
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Hyde JS. Autobiography of James S. Hyde. APPLIED MAGNETIC RESONANCE 2017; 48:1103-1147. [PMID: 29962662 PMCID: PMC6022859 DOI: 10.1007/s00723-017-0950-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The papers, book chapters, reviews, and patents by James S. Hyde in the bibliography of this document have been separated into EPR and MRI sections, and within each section by topics. Within each topic, publications are listed chronologically. A brief summary is provided for each patent listed. A few publications and patents that do not fit this schema have been omitted. This list of publications is preceded by a scientific autobiography that focuses on selected topics that are judged to have been of most scientific importance. References to many of the publications and patents in the bibliography are made in the autobiography.
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Affiliation(s)
- James S Hyde
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plan Road, Milwaukee, WI 53226; 414-955-4000; ; ORCID: 0000-0002-3023-1243
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15
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Kashef N, Hamblin MR. Can microbial cells develop resistance to oxidative stress in antimicrobial photodynamic inactivation? Drug Resist Updat 2017; 31:31-42. [PMID: 28867242 DOI: 10.1016/j.drup.2017.07.003] [Citation(s) in RCA: 197] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/28/2017] [Accepted: 07/13/2017] [Indexed: 01/08/2023]
Abstract
Infections have been a major cause of disease throughout the history of humans on earth. With the introduction of antibiotics, it was thought that infections had been conquered. However, bacteria have been able to develop resistance to antibiotics at an exponentially increasing rate. The growing threat from multi-drug resistant organisms calls for intensive action to prevent the emergence of totally resistant and untreatable infections. Novel, non-invasive, non-antibiotic strategies are needed that act more efficiently and faster than current antibiotics. One promising alternative is antimicrobial photodynamic inactivation (APDI), an approach that produces reactive oxygen species when dyes and light are combined. So far, it has been questionable if bacteria can develop resistance against APDI. This review paper gives an overview of recent studies concerning the susceptibility of bacteria towards oxidative stress, and suggests possible mechanisms of the development of APDI-resistance that should at least be addressed. Some ways to potentiate APDI and also to overcome future resistance are suggested.
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Affiliation(s)
- Nasim Kashef
- Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran; Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, 02114, USA; Department of Dermatology, Harvard Medical School, Boston, MA, 02115, USA.
| | - Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, 02114, USA; Department of Dermatology, Harvard Medical School, Boston, MA, 02115, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, 02139, USA.
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16
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Möller MN, Li Q, Chinnaraj M, Cheung HC, Lancaster JR, Denicola A. Solubility and diffusion of oxygen in phospholipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2923-2930. [PMID: 27614191 DOI: 10.1016/j.bbamem.2016.09.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 07/15/2016] [Accepted: 09/06/2016] [Indexed: 11/16/2022]
Abstract
The transport of oxygen and other nonelectrolytes across lipid membranes is known to depend on both diffusion and solubility in the bilayer, and to be affected by changes in the physical state and by the lipid composition, especially the content of cholesterol and unsaturated fatty acids. However, it is not known how these factors affect diffusion and solubility separately. Herein we measured the partition coefficient of oxygen in liposome membranes of dilauroyl-, dimiristoyl- and dipalmitoylphosphatidylcholine in buffer at different temperatures using the equilibrium-shift method with electrochemical detection. The apparent diffusion coefficient was measured following the fluorescence quenching of 1-pyrenedodecanoate inserted in the liposome bilayers under the same conditions. The partition coefficient varied with the temperature and the physical state of the membrane, from below 1 in the gel state to above 2.8 in the liquid-crystalline state in DMPC and DPPC membranes. The partition coefficient was directly proportional to the partial molar volume and was then associated to the increase in free-volume in the membrane as a function of temperature. The apparent diffusion coefficients were corrected by the partition coefficients and found to be nearly the same, with a null dependence on viscosity and physical state of the membrane, probably because the pyrene is disturbing the surrounding lipids and thus becoming insensitive to changes in membrane viscosity. Combining our results with those of others, it is apparent that both solubility and diffusion increase when increasing the temperature or when comparing a membrane in the gel to one in the fluid state.
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Affiliation(s)
- Matías N Möller
- Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica, Facultad de Ciencias, and Center for Free Radical and Biomedical Research, Universidad de la República, Montevideo, Uruguay.
| | - Qian Li
- Department of Anesthesiology, Center for Free Radical Biology, The University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Mathivanan Chinnaraj
- Department of Biochemistry and Molecular Genetics, The University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Herbert C Cheung
- Department of Biochemistry and Molecular Genetics, The University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Jack R Lancaster
- Departments of Pharmacology and Chemical Biology, Medicine, and Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Ana Denicola
- Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica, Facultad de Ciencias, and Center for Free Radical and Biomedical Research, Universidad de la República, Montevideo, Uruguay.
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17
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Gambino M, Cappitelli F. Mini-review: Biofilm responses to oxidative stress. BIOFOULING 2016; 32:167-178. [PMID: 26901587 DOI: 10.1080/08927014.2015.1134515] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 12/14/2015] [Indexed: 06/05/2023]
Abstract
Biofilms constitute the predominant microbial style of life in natural and engineered ecosystems. Facing harsh environmental conditions, microorganisms accumulate reactive oxygen species (ROS), potentially encountering a dangerous condition called oxidative stress. While high levels of oxidative stress are toxic, low levels act as a cue, triggering bacteria to activate effective scavenging mechanisms or to shift metabolic pathways. Although a complex and fragmentary picture results from current knowledge of the pathways activated in response to oxidative stress, three main responses are shown to be central: the existence of common regulators, the production of extracellular polymeric substances, and biofilm heterogeneity. An investigation into the mechanisms activated by biofilms in response to different oxidative stress levels could have important consequences from ecological and economic points of view, and could be exploited to propose alternative strategies to control microbial virulence and deterioration.
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Affiliation(s)
- Michela Gambino
- a Department of Food, Environmental and Nutrition Sciences , Università degli Studi di Milano , Milan , Italy
| | - Francesca Cappitelli
- a Department of Food, Environmental and Nutrition Sciences , Università degli Studi di Milano , Milan , Italy
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18
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Amounts of phospholipids and cholesterol in lipid domains formed in intact lens membranes: Methodology development and its application to studies of porcine lens membranes. Exp Eye Res 2015; 140:179-186. [PMID: 26384651 DOI: 10.1016/j.exer.2015.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 08/29/2015] [Accepted: 09/14/2015] [Indexed: 11/22/2022]
Abstract
An electron paramagnetic resonance spin-labeling method has been developed that allows quantitative evaluation of the amounts of phospholipids and cholesterol in lipid domains of intact fiber-cell plasma membranes isolated from cortical and nuclear regions of eye lenses. The long term goal of this research is the assessment of organizational changes in human lens fiber cell membranes that occur with age and during cataract development. The measurements needed to be performed on lens membranes prepared from eyes of single donors and from single eyes. For these types of studies it is necessary to separate the age/cataract related changes from preparation/technique related changes. Human lenses differ not only because of age, but also because of the varying health histories of the donors. To solve these problems the sample-to-sample preparation/technique related changes were evaluated for cortical and nuclear lens membranes prepared from single porcine eyes. It was assumed that the differences due to the age (animals were two year old) and environmental conditions for raising these animals were minimal. Mean values and standard deviations from preparation/technique changes for measured amounts of lipids in membrane domains were calculated. Statistical analysis (Student's t-test) of the data also allowed determining the differences of mean values which were statistically significant with P ≤ 0.05. These differences defined for porcine lenses will be used for comparison of amounts of lipids in domains in human lens membranes prepared from eyes of single donors and from single eyes. Greater separations will indicate that differences were statistically significant with (P ≤ 0.05) and that they came from different than preparation/technique sources. Results confirmed that in nuclear porcine membranes the amounts of lipids in domains created due to the presence of membrane proteins were greater than those in cortical membranes and the differences were larger than the differences observed for human intact fiber cell membranes [Raguz, M. Mainali, L., O'Brien, W.J., and Subczynski, W.K. (2015) Exp. Eye Res.]. Lipids in porcine nuclear fiber cell plasma membranes were more rigid and less permeable to oxygen than in human nuclear membranes. Most likely the significant differences in the lipid composition were responsible for the observed differences.
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19
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Hristova-Neeley D, Neshchadin D, Gescheidt G. Time-Resolved EPR as a Tool to Investigate Oxygen Quenching in Photoinitiated Radical Polymerizations. J Phys Chem B 2015. [DOI: 10.1021/acs.jpcb.5b04263] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniela Hristova-Neeley
- Institute of Physical and
Theoretical Chemistry, NAWI Graz, Graz University of Technology, Stremayrgasse
9, 8010 Graz, Austria
| | - Dmytro Neshchadin
- Institute of Physical and
Theoretical Chemistry, NAWI Graz, Graz University of Technology, Stremayrgasse
9, 8010 Graz, Austria
| | - Georg Gescheidt
- Institute of Physical and
Theoretical Chemistry, NAWI Graz, Graz University of Technology, Stremayrgasse
9, 8010 Graz, Austria
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20
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Shabnam N, Sharmila P, Sharma A, Strasser RJ, Pardha-Saradhi P. Mitochondrial electron transport protects floating leaves of long leaf pondweed (Potamogeton nodosus Poir) against photoinhibition: comparison with submerged leaves. PHOTOSYNTHESIS RESEARCH 2015; 125:305-319. [PMID: 25366828 DOI: 10.1007/s11120-014-0051-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 10/16/2014] [Indexed: 06/04/2023]
Abstract
Investigations were carried to unravel mechanism(s) for higher tolerance of floating over submerged leaves of long leaf pondweed (Potamogeton nodosus Poir) against photoinhibition. Chloroplasts from floating leaves showed ~5- and ~6.4-fold higher Photosystem (PS) I (reduced dichlorophenol-indophenol → methyl viologen → O2) and PS II (H2O → parabenzoquine) activities over those from submerged leaves. The saturating rate (V max) of PS II activity of chloroplasts from floating and submerged leaves reached at ~600 and ~230 µmol photons m(-2) s(-1), respectively. Photosynthetic electron transport rate in floating leaves was over 5-fold higher than in submerged leaves. Further, floating leaves, as compared to submerged leaves, showed higher F v/F m (variable to maximum chlorophyll fluorescence, a reflection of PS II efficiency), as well as a higher potential to withstand photoinhibitory damage by high light (1,200 µmol photons m(-2) s(-1)). Cells of floating leaves had not only higher mitochondria to chloroplast ratio, but also showed many mitochondria in close vicinity of chloroplasts. Electron transport (NADH → O2; succinate → O2) in isolated mitochondria of floating leaves was sensitive to both cyanide (CN(-)) and salicylhydroxamic acid (SHAM), whereas those in submerged leaves were sensitive to CN(-), but virtually insensitive to SHAM, revealing the presence of alternative oxidase in mitochondria of floating, but not of submerged, leaves. Further, the potential of floating leaves to withstand photoinhibitory damage was significantly reduced in the presence of CN(-) and SHAM, individually and in combination. Our experimental results establish that floating leaves possess better photosynthetic efficiency and capacity to withstand photoinhibition compared to submerged leaves; and mitochondria play a pivotal role in protecting photosynthetic machinery of floating leaves against photoinhibition, most likely by oxidation of NAD(P)H and reduction of O2.
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Affiliation(s)
- Nisha Shabnam
- Department of Environmental Studies, University of Delhi, Delhi, 110007, India
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21
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Tikhonov AN. Induction events and short-term regulation of electron transport in chloroplasts: an overview. PHOTOSYNTHESIS RESEARCH 2015; 125:65-94. [PMID: 25680580 DOI: 10.1007/s11120-015-0094-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 01/26/2015] [Indexed: 05/03/2023]
Abstract
Regulation of photosynthetic electron transport at different levels of structural and functional organization of photosynthetic apparatus provides efficient performance of oxygenic photosynthesis in plants. This review begins with a brief overview of the chloroplast electron transport chain. Then two noninvasive biophysical methods (measurements of slow induction of chlorophyll a fluorescence and EPR signals of oxidized P700 centers) are exemplified to illustrate the possibility of monitoring induction events in chloroplasts in vivo and in situ. Induction events in chloroplasts are considered and briefly discussed in the context of short-term mechanisms of the following regulatory processes: (i) pH-dependent control of the intersystem electron transport; (ii) the light-induced activation of the Calvin-Benson cycle; (iii) optimization of electron transport due to fitting alternative pathways of electron flow and partitioning light energy between photosystems I and II; and (iv) the light-induced remodeling of photosynthetic apparatus and thylakoid membranes.
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22
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Raguz M, Mainali L, O'Brien WJ, Subczynski WK. Lipid domains in intact fiber-cell plasma membranes isolated from cortical and nuclear regions of human eye lenses of donors from different age groups. Exp Eye Res 2015; 132:78-90. [PMID: 25617680 DOI: 10.1016/j.exer.2015.01.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 01/05/2015] [Accepted: 01/20/2015] [Indexed: 02/02/2023]
Abstract
The results reported here clearly document changes in the properties and the organization of fiber-cell membrane lipids that occur with age, based on electron paramagnetic resonance (EPR) analysis of lens membranes of clear lenses from donors of age groups from 0 to 20, 21 to 40, and 61 to 80 years. The physical properties, including profiles of the alkyl chain order, fluidity, hydrophobicity, and oxygen transport parameter, were investigated using EPR spin-labeling methods, which also provide an opportunity to discriminate coexisting lipid domains and to evaluate the relative amounts of lipids in these domains. Fiber-cell membranes were found to contain three distinct lipid environments: bulk lipid domain, which appears minimally affected by membrane proteins, and two domains that appear due to the presence of membrane proteins, namely boundary and trapped lipid domains. In nuclear membranes the amount of boundary and trapped phospholipids as well as the amount of cholesterol in trapped lipid domains increased with the donors' age and was greater than that in cortical membranes. The difference between the amounts of lipids in domains uniquely formed due to the presence of membrane proteins in nuclear and cortical membranes increased with the donors' age. It was also shown that cholesterol was to a large degree excluded from trapped lipid domains in cortical membranes. It is evident that the rigidity of nuclear membranes was greater than that of cortical membranes for all age groups. The amount of lipids in domains of low oxygen permeability, mainly in trapped lipid domains, were greater in nuclear than cortical membranes and increased with the age of donors. These results indicate that the nuclear fiber cell plasma membranes were less permeable to oxygen than cortical membranes and become less permeable to oxygen with age. In clear lenses, age-related changes in the lens lipid and protein composition and organization appear to occur in ways that increase fiber cell plasma membrane resistance to oxygen permeation.
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Affiliation(s)
- Marija Raguz
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Medical Physics and Biophysics, School of Medicine, University of Split, Split, Croatia
| | - Laxman Mainali
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - William J O'Brien
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Witold K Subczynski
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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23
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Jajić I, Wiśniewska-Becker A, Sarna T, Jemioła-Rzemińska M, Strzałka K. EPR spin labeling measurements of thylakoid membrane fluidity during barley leaf senescence. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:1046-1053. [PMID: 24974331 DOI: 10.1016/j.jplph.2014.03.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 03/26/2014] [Accepted: 03/29/2014] [Indexed: 06/03/2023]
Abstract
Physical properties of thylakoid membranes isolated from barley were investigated by the electron paramagnetic resonance (EPR) spin labeling technique. EPR spectra of stearic acid spin labels 5-SASL and 16-SASL were measured as a function of temperature in secondary barley leaves during natural and dark-induced senescence. Oxygen transport parameter was determined from the power saturation curves of the spin labels obtained in the presence and absence of molecular oxygen at 25°C. Parameters of EPR spectra of both spin labels showed an increase in the thylakoid membrane fluidity during senescence, in the headgroup area of the membrane, as well as in its interior. The oxygen transport parameter also increased with age of barley, indicating easier diffusion of oxygen within the membrane and its higher fluidity. The data are consistent with age-related changes of the spin label parameters obtained directly by EPR spectroscopy. Similar outcome was also observed when senescence was induced in mature secondary barley leaves by dark incubation. Such leaves showed higher membrane fluidity in comparison with leaves of the same age, grown under light conditions. Changes in the membrane fluidity of barley secondary leaves were compared with changes in the levels of carotenoids (car) and proteins, which are known to modify membrane fluidity. Determination of total car and proteins showed linear decrease in their level with senescence. The results indicate that thylakoid membrane fluidity of barley leaves increases with senescence; the changes are accompanied with a decrease in the content of car and proteins, which could be a contributing factor.
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Affiliation(s)
- Ivan Jajić
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University in Krakow, Ul. Gronostajowa, 7, 30-387 Krakow, Poland
| | - Anna Wiśniewska-Becker
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University in Krakow, Ul. Gronostajowa, 7, 30-387 Krakow, Poland
| | - Tadeusz Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University in Krakow, Ul. Gronostajowa, 7, 30-387 Krakow, Poland
| | - Małgorzata Jemioła-Rzemińska
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University in Krakow, Ul. Gronostajowa, 7, 30-387 Krakow, Poland
| | - Kazimierz Strzałka
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University in Krakow, Ul. Gronostajowa, 7, 30-387 Krakow, Poland.
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24
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Kihara S, Hartzler DA, Savikhin S. Oxygen concentration inside a functioning photosynthetic cell. Biophys J 2014; 106:1882-9. [PMID: 24806920 PMCID: PMC4017319 DOI: 10.1016/j.bpj.2014.03.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 02/13/2014] [Accepted: 03/12/2014] [Indexed: 11/23/2022] Open
Abstract
The excess oxygen concentration in the photosynthetic membranes of functioning oxygenic photosynthetic cells was estimated using classical diffusion theory combined with experimental data on oxygen production rates of cyanobacterial cells. The excess oxygen concentration within the plesiomorphic cyanobacterium Gloeobactor violaceus is only 0.025 μM, or four orders of magnitude lower than the oxygen concentration in air-saturated water. Such a low concentration suggests that the first oxygenic photosynthetic bacteria in solitary form could have evolved ∼2.8 billion years ago without special mechanisms to protect them against reactive oxygen species. These mechanisms instead could have been developed during the following ∼500 million years while the oxygen level in the Earth's atmosphere was slowly rising. Excess oxygen concentrations within individual cells of the apomorphic cyanobacteria Synechocystis and Synechococcus are 0.064 and 0.25 μM, respectively. These numbers suggest that intramembrane and intracellular proteins in isolated oxygenic photosynthetic cells are not subjected to excessively high oxygen levels. The situation is different for closely packed colonies of photosynthetic cells. Calculations show that the excess concentration within colonies that are ∼40 μm or larger in diameter can be comparable to the oxygen concentration in air-saturated water, suggesting that species forming colonies require protection against reactive oxygen species even in the absence of oxygen in the surrounding atmosphere.
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Affiliation(s)
- Shigeharu Kihara
- Department of Physics, Purdue University, West Lafayette, Indiana
| | | | - Sergei Savikhin
- Department of Physics, Purdue University, West Lafayette, Indiana.
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25
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Raguz M, Mainali L, O'Brien WJ, Subczynski WK. Lipid-protein interactions in plasma membranes of fiber cells isolated from the human eye lens. Exp Eye Res 2014; 120:138-51. [PMID: 24486794 DOI: 10.1016/j.exer.2014.01.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/20/2014] [Accepted: 01/22/2014] [Indexed: 11/19/2022]
Abstract
The protein content in human lens membranes is extremely high, increases with age, and is higher in the nucleus as compared with the cortex, which should strongly affect the organization and properties of the lipid bilayer portion of intact membranes. To assess these effects, the intact cortical and nuclear fiber cell plasma membranes isolated from human lenses from 41- to 60-year-old donors were studied using electron paramagnetic resonance spin-labeling methods. Results were compared with those obtained for lens lipid membranes prepared from total lipid extracts from human eyes of the same age group [Mainali, L., Raguz, M., O'Brien, W. J., and Subczynski, W. K. (2013) Biochim. Biophys. Acta]. Differences were considered to be mainly due to the effect of membrane proteins. The lipid-bilayer portions of intact membranes were significantly less fluid than lipid bilayers of lens lipid membranes, prepared without proteins. The intact membranes were found to contain three distinct lipid environments termed the bulk lipid domain, boundary lipid domain, and trapped lipid domain. However, the cholesterol bilayer domain, which was detected in cortical and nuclear lens lipid membranes, was not detected in intact membranes. The relative amounts of bulk and trapped lipids were evaluated. The amount of lipids in domains uniquely formed due to the presence of membrane proteins was greater in nuclear membranes than in cortical membranes. Thus, it is evident that the rigidity of nuclear membranes is greater than that of cortical membranes. Also the permeability coefficients for oxygen measured in domains of nuclear membranes were significantly lower than appropriate coefficients measured in cortical membranes. Relationships between the organization of lipids into lipid domains in fiber cells plasma membranes and the organization of membrane proteins are discussed.
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Affiliation(s)
- Marija Raguz
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA; Department of Medical Physics and Biophysics, School of Medicine, University of Split, Split, Croatia
| | - Laxman Mainali
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - William J O'Brien
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Witold K Subczynski
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
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26
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Imlay JA. The molecular mechanisms and physiological consequences of oxidative stress: lessons from a model bacterium. Nat Rev Microbiol 2013; 11:443-54. [PMID: 23712352 DOI: 10.1038/nrmicro3032] [Citation(s) in RCA: 983] [Impact Index Per Article: 89.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Oxic environments are hazardous. Molecular oxygen adventitiously abstracts electrons from many redox enzymes, continuously forming intracellular superoxide and hydrogen peroxide. These species can destroy the activities of metalloenzymes and the integrity of DNA, forcing organisms to protect themselves with scavenging enzymes and repair systems. Nevertheless, elevated levels of oxidants quickly poison bacteria, and both microbial competitors and hostile eukaryotic hosts exploit this vulnerability by assaulting these bacteria with peroxides or superoxide-forming antibiotics. In response, bacteria activate elegant adaptive strategies. In this Review, I summarize our current knowledge of oxidative stress in Escherichia coli, the model organism for which our understanding of damage and defence is most well developed.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
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27
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Mainali L, Raguz M, O'Brien WJ, Subczynski WK. Properties of fiber cell plasma membranes isolated from the cortex and nucleus of the porcine eye lens. Exp Eye Res 2012; 97:117-29. [PMID: 22326289 DOI: 10.1016/j.exer.2012.01.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2011] [Revised: 01/21/2012] [Accepted: 01/26/2012] [Indexed: 11/28/2022]
Abstract
The organization and physical properties of the lipid bilayer portion of intact cortical and nuclear fiber cell plasma membranes isolated from the eye lenses of two-year-old pigs were studied using electron paramagnetic resonance (EPR) spin-labeling. Membrane fluidity, hydrophobicity, and the oxygen transport parameter (OTP) were assessed from the EPR spectra of precisely positioned spin labels. Intact cortical and nuclear membranes, which include membrane proteins, were found to contain three distinct lipid environments. These lipid environments were termed the bulk lipid domain, boundary lipid domain, and trapped lipid domain (lipids in protein aggregates). The amount of boundary and trapped lipids was greater in intact nuclear membranes than in cortical membranes. The properties of intact membranes were compared with the organization and properties of lens lipid membranes made of the total lipid extracts from the lens cortex or nucleus. In cortical lens lipid membranes, only one homogenous environment was detected, which was designated as a bulk lipid domain (phospholipid bilayer saturated with cholesterol). Lens lipid membranes prepared from the lens nucleus possessed two domains, assigned as a bulk lipid domain and a cholesterol bilayer domain (CBD). In intact nuclear membranes, it was difficult to discriminate the CBD, which was clearly detected in nuclear lens lipid membranes, because the OTP measured in the CBD is the same as in the domain formed by trapped lipids. The two domains unique to intact membranes-namely, the domain formed by boundary lipids and the domain formed by trapped lipids-were most likely formed due to the presence of membrane proteins. It is concluded that formation of rigid and practically impermeable domains is enhanced in the lens nucleus, indicating changes in membrane composition that may help to maintain low oxygen concentration in this lens region.
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Affiliation(s)
- Laxman Mainali
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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28
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van der Veen S, Abee T. Generation of variants in Listeria monocytogenes continuous-flow biofilms is dependent on radical-induced DNA damage and RecA-mediated repair. PLoS One 2011; 6:e28590. [PMID: 22163039 PMCID: PMC3230620 DOI: 10.1371/journal.pone.0028590] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 11/11/2011] [Indexed: 12/31/2022] Open
Abstract
The food-borne pathogen Listeria monocytogenes is a Gram-positive microaerophilic facultative anaerobic rod and the causative agent of the devastating disease listeriosis. L. monocytogenes is able to form biofilms in the food processing environment. Since biofilms are generally hard to eradicate, they can function as a source for food contamination. In several occasions biofilms have been identified as a source for genetic variability, which potentially can result in adaptation of strains to food processing or clinical conditions. However, nothing is known about mutagenesis in L. monocytogenes biofilms and the possible mechanisms involved. In this study, we showed that the generation of genetic variants was specifically induced in continuous-flow biofilms of L. monocytogenes, but not in static biofilms. Using specific dyes and radical inhibitors, we showed that the formation of superoxide and hydroxyl radicals was induced in continuous-flow biofilms, which was accompanied with in an increase in DNA damage. Promoter reporter studies showed that recA, which is an important component in DNA repair and the activator of the SOS response, is activated in continuous-flow biofilms and that activation was dependent on radical-induced DNA damage. Furthermore, continuous-flow biofilm experiments using an in-frame recA deletion mutant verified that RecA is required for induced generation of genetic variants. Therefore, we can conclude that generation of genetic variants in L. monocytogenes continuous-flow biofilms results from radical-induced DNA damage and RecA-mediated mutagenic repair of the damaged DNA.
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Affiliation(s)
- Stijn van der Veen
- Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Tjakko Abee
- Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University and Research Centre, Wageningen, The Netherlands
- * E-mail:
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Lipids in photosystem II: Multifunctional cofactors. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2011; 104:19-34. [DOI: 10.1016/j.jphotobiol.2011.02.025] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 01/31/2011] [Accepted: 02/01/2011] [Indexed: 11/21/2022]
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Pulmonary surfactant layers accelerate O2 diffusion through the air-water interface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1281-4. [DOI: 10.1016/j.bbamem.2010.03.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Accepted: 03/02/2010] [Indexed: 01/08/2023]
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Tsai AG, Cabrales P, Intaglietta M. The physics of oxygen delivery: facts and controversies. Antioxid Redox Signal 2010; 12:683-91. [PMID: 19757988 PMCID: PMC2834451 DOI: 10.1089/ars.2009.2519] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 09/15/2009] [Accepted: 09/16/2009] [Indexed: 11/13/2022]
Abstract
At the microvascular level, the radial oxygen gradient is greater in arterioles than in any other vascular segment and thus drives the oxygen from the blood (high concentration, source) into the perivascular tissue (low concentration, sink). Thus, arterioles appear to be the main suppliers of oxygen to the tissue, in contrast to the capillaries, where the oxygen gradient is only a few millimeters of mercury. However, longitudinal oxygen loss from arteriolar blood is higher than can be solely accounted for by diffusion. This discrepancy becomes evident when determining how oxygen is distributed in the microvascular network, an approach that requires confirmation of the data in terms of mass balance and thermodynamic considerations. A fundamental difficulty is that measuring tissue Po 2 is complicated by methods, exposure of tissue, interpretation, and resolution. The literature reports mean tissue Po 2 as low as 5 and up to 50 mm Hg. This large variability is due to the differences in techniques, species, tissue, handling, and interpretation of signals used to resolve Po 2 levels. Improving measurement accuracy and physiological interpretation of the emerging Po 2 data is ongoing. We present an analysis of our current understanding of how tissue is supplied by oxygen at the microscopic level in terms of present results from laboratories using differing methods. Antioxid. Redox Signal. 12, 683–691.
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Affiliation(s)
- Amy G. Tsai
- Department of Bioengineering, University of California, San Diego, La Jolla, California
| | | | - Marcos Intaglietta
- Department of Bioengineering, University of California, San Diego, La Jolla, California
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Kern J, Zouni A, Guskov A, Krauß N. Lipids in the Structure of Photosystem I, Photosystem II and the Cytochrome b 6 f Complex. LIPIDS IN PHOTOSYNTHESIS 2009. [DOI: 10.1007/978-90-481-2863-1_10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Nakagawa K. EPR Investigations of Spin-Probe Dynamics in Aqueous Dispersions of a Nonionic Amphiphilic Compound. J AM OIL CHEM SOC 2008. [DOI: 10.1007/s11746-008-1317-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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34
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Abstract
Life evolved in an anaerobic world; therefore, fundamental enzymatic mechanisms and biochemical pathways were refined and integrated into metabolism in the absence of any selective pressure to avoid reactivity with oxygen. After photosystem II appeared, environmental oxygen levels rose very slowly. During this time, microorganisms acquired oxygen tolerance by jettisoning enzymes that use glycyl radicals and exposed low-potential iron-sulfur clusters, which can be directly poisoned by oxygen. They also developed mechanisms to defend themselves against superoxide (O(2)()) and hydrogen peroxide, partially reduced oxygen species that are generated as inadvertent by-products of aerobic metabolism. Contemporary organisms have inherited both the vulnerabilities and the defenses of these ancestral microbes. Current research seeks to identify these, and bacteria comprise an exceptionally accessible experimental system that has provided many of the answers. This manuscript reviews recent developments and identifies remaining puzzles.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA.
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Hillmann F, Fischer RJ, Saint-Prix F, Girbal L, Bahl H. PerR acts as a switch for oxygen tolerance in the strict anaerobe Clostridium acetobutylicum. Mol Microbiol 2008; 68:848-60. [DOI: 10.1111/j.1365-2958.2008.06192.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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36
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Abstract
Life evolved in an anaerobic world; therefore, fundamental enzymatic mechanisms and biochemical pathways were refined and integrated into metabolism in the absence of any selective pressure to avoid reactivity with oxygen. After photosystem II appeared, environmental oxygen levels rose very slowly. During this time, microorganisms acquired oxygen tolerance by jettisoning enzymes that use glycyl radicals and exposed low-potential iron-sulfur clusters, which can be directly poisoned by oxygen. They also developed mechanisms to defend themselves against superoxide (O(2)()) and hydrogen peroxide, partially reduced oxygen species that are generated as inadvertent by-products of aerobic metabolism. Contemporary organisms have inherited both the vulnerabilities and the defenses of these ancestral microbes. Current research seeks to identify these, and bacteria comprise an exceptionally accessible experimental system that has provided many of the answers. This manuscript reviews recent developments and identifies remaining puzzles.
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Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA.
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Kapellos GE, Alexiou TS, Payatakes AC. A multiscale theoretical model for diffusive mass transfer in cellular biological media. Math Biosci 2007; 210:177-237. [PMID: 17572450 DOI: 10.1016/j.mbs.2007.04.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 12/28/2006] [Accepted: 04/25/2007] [Indexed: 11/26/2022]
Abstract
An integrated methodology is developed for the theoretical analysis of solute transport and reaction in cellular biological media, such as tissues, microbial flocs, and biofilms. First, the method of local spatial averaging with a weight function is used to establish the equation which describes solute conservation at the cellular biological medium scale, starting with a continuum-based formulation of solute transport at finer spatial scales. Second, an effective-medium model is developed for the self-consistent calculation of the local diffusion coefficient in the cellular biological medium, including the effects of the structural heterogeneity of the extra-cellular space and the reversible adsorption to extra-cellular polymers. The final expression for the local effective diffusion coefficient is: D(Abeta)=lambda(beta)D(Aupsilon), where D(Aupsilon) is the diffusion coefficient in water, and lambda(beta) is a function of the composition and fundamental geometric and physicochemical system properties, including the size of solute molecules, the size of extra-cellular polymer fibers, and the mass permeability of the cell membrane. Furthermore, the analysis sheds some light on the function of the extra-cellular hydrogel as a diffusive barrier to solute molecules approaching the cell membrane, and its implications on the transport of chemotherapeutic agents within a cellular biological medium. Finally, the model predicts the qualitative trend as well as the quantitative variability of a large number of published experimental data on the diffusion coefficient of oxygen in cell-entrapping gels, microbial flocs, biofilms, and mammalian tissues.
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Affiliation(s)
- George E Kapellos
- Institute of Chemical Engineering and High Temperature Chemical Processes - FORTH, University of Patras, GR-26504 Patras, Greece.
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Ivanov II, Loktyushkin AV, Gus'kova RA, Vasil'ev NS, Fedorov GE, Rubin AB. Oxygen channels of erythrocyte membrane. DOKL BIOCHEM BIOPHYS 2007; 414:137-40. [PMID: 17695321 DOI: 10.1134/s160767290703012x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- I I Ivanov
- Biological Faculty, Moscow State University, Vorob'evy gory, Moscow, 119992 Russia
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Nakagawa K. Spin-Probe Investigations of Head Group Behavior in Aqueous Dispersions of a Nonionic Amphiphilic Compound. Lipids 2007; 42:457-62. [PMID: 17476549 DOI: 10.1007/s11745-007-3048-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Accepted: 02/23/2007] [Indexed: 11/26/2022]
Abstract
Head group behavior of nonionic amphiphilic compound, (poly(oxyethylene) hydrogenated castor oil, HCO), in aqueous dispersions were investigated by EPR (electron paramagnetic resonance) in conjunction with a modern slow-tumbling simulation. The aliphatic spin probes, 5-doxylstearic acid (5-DSA) and 3beta-doxyl-5alpha-cholestane (CHL), were used to obtain fluidity of the surface region of the membrane. The order parameter (S (0)) using the simulation for 5-DSA and CHL in the region were approximately 0.4 and 0.2, respectively. The ordering results suggest that the head group region of the membrane is somewhat fluid. The rotational diffusion coefficients (R ( perpendicular) approximately 1/(6tau(R))) for the probes were 3.4 x 10(7) and 7.1 x 10(7) s(-1), respectively. Activation energies, calculated using the temperature dependence of diffusion coefficients, were 18 and 17 kJ/mol for the probes. The EPR results imply that the CHL probe in the HCO membrane has quite different behavior in comparison with that of PC (phosphatidylcholine) from egg. Thus, the present EPR analyses have provided quantitative insight into the surface region of the amphiphilic membrane.
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Affiliation(s)
- Kouichi Nakagawa
- RI Research Center, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan.
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Garstka M, Nejman P, Rosiak M. The action of oxygen on chlorophyll fluorescence quenching and absorption spectra in pea thylakoid membranes under the steady-state conditions. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2004; 77:79-92. [PMID: 15542365 DOI: 10.1016/j.jphotobiol.2004.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Revised: 08/21/2004] [Accepted: 08/24/2004] [Indexed: 11/23/2022]
Abstract
The effect of oxygen concentration on both absorption and chlorophyll fluorescence spectra was investigated in isolated pea thylakoids at weak actinic light under the steady-state conditions. Upon the rise of oxygen concentration from anaerobiosis up to 412 microM a gradual absorbance increase around both 437 and 670 nm was observed, suggesting the disaggregation of LHCII and destacking of thylakoids. Simultaneously, an increase in oxygen concentration resulted in a decline in the Chl fluorescence at 680 nm to about 60% of the initial value. The plot of normalized Chl fluorescence quenching, F(-O(2))/F(+O(2)), showed discontinuity above 275 microM O(2), revealing two phases of quenching, at both lower and higher oxygen concentrations. The inhibition of photosystem II by DCMU or atrazine as well as that of cyt b(6)f by myxothiazol attenuated the oxygen-induced quenching events observed above 275 microM O(2), but did not modify the first phase of oxygen action. These data imply that the oxygen mediated Chl fluorescence quenching is partially independent on non-cyclic electron flow. The second phase of oxygen-induced decline in Chl fluorescence is diminished in thylakoids with poisoned PSII and cyt b(6)f activities and treated with rotenone or N-ethylmaleimide to inhibit NAD(P)H-plastoquinone dehydrogenase. The data suggest that under weak light and high oxygen concentration the Chl fluorescence quenching results from interactions between oxygen and PSI, cyt b(6)f and Ndh. On the contrary, inhibition of non-cyclic electron flow by antimycin A or uncoupling of thylakoids by carbonyl cyanide m-chlorophenyl hydrazone did not modify the steady-state oxygen effect on Chl fluorescence quenching. The addition of NADH protected thylakoids against oxygen-induced Chl fluorescence quenching, whereas in the presence of exogenic duroquinone the decrease in Chl fluorescence to one half of the initial level did not result from the oxygen effect, probably due to oxygen action as a weak electron acceptor from PQ pool and an insufficient non-photochemical quencher. The data indicate that mechanism of oxygen-induced Chl fluorescence quenching depends significantly on oxygen concentration and is related to both structural rearrangement of thylakoids and the direct oxygen reduction by photosynthetic complexes.
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Affiliation(s)
- Maciej Garstka
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, Warsaw University, Miecznikowa 1, PL-02-096 Warszawa, Poland.
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41
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Ivanov II, Fedorov GE, Gus'kova RA, Ivanov KI, Rubin AB. Permeability of lipid membranes to dioxygen. Biochem Biophys Res Commun 2004; 322:746-50. [PMID: 15336527 DOI: 10.1016/j.bbrc.2004.07.187] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2004] [Indexed: 11/20/2022]
Abstract
It is commonly supposed that dioxygen (O(2)) transport through biomembranes is ensured by the high permeability of a lipid bilayer in which O(2) diffusion mobility is close to that in water. However, the fact that microviscosity of lipid membranes is higher than that of water by two to three orders of magnitude speaks against this concept. Therefore, in this work we investigated the influence of surface lipid monolayers on oxygen diffusion flow directed from air to aqueous phase. We show that for lipid monolayers, the O(2) permeability coefficients are within the range of 10(-4) to 10(-5)m/s. These values are three to four orders of magnitude lower than has been previously thought, indicating that lipid membranes constitute a considerable barrier to O(2) diffusion. From this, we suggest that membranes of aerobic organisms contain O(2) channels to ensure the high-volume transmembrane O(2) flows.
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Affiliation(s)
- Ilya I Ivanov
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia.
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42
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Shinoda W, Mikami M, Baba T, Hato M. Molecular Dynamics Study on the Effects of Chain Branching on the Physical Properties of Lipid Bilayers: 2. Permeability. J Phys Chem B 2004. [DOI: 10.1021/jp035998+] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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43
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Nedeianu S, Páli T, Marsh D. Membrane penetration of nitric oxide and its donor S-nitroso-N-acetylpenicillamine: a spin-label electron paramagnetic resonance spectroscopic study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004; 1661:135-43. [PMID: 15003876 DOI: 10.1016/j.bbamem.2003.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2003] [Revised: 12/12/2003] [Accepted: 12/15/2003] [Indexed: 11/18/2022]
Abstract
S-nitroso-N-acetylpenicillamine (SNAP) is a pharmacological agent with diverse biological effects that are mainly attributable to its favorable characteristics as a nitric oxide (NO)-evolving agent. It is found that SNAP incorporates readily into dimyristoyl phosphatidylcholine (DMPC) bilayer membranes; and an approximate penetration profile was obtained from the depth dependence of the perturbation that it exerts on spin-labeled lipid chains. The profile of SNAP locates it deep in the hydrophobic core of both fluid- and gel-phase membranes. The spin relaxation enhancement of spin-labeled phospholipids with nitroxide group located at different depths in DMPC membranes was determined for nitric oxide (NO) and molecular oxygen (O(2)), at close to atomic spatial resolution. The relaxation enhancement, which is proportional to the corresponding vertical membrane profile of the concentration-diffusion product, was measured in the gel and fluid phases of the lipid bilayer. No significant membrane penetration was observed in the gel phase for the two water-dissolved gases. In the fluid phase, the transmembrane profiles of NO and O(2) are similar and could be well described by a sigmoidal function with a maximum in the center of the bilayer, but that of NO is less steep and is shifted toward the center of the membrane, relative to that of O(2). These differences can be attributed mainly to the difference in hydrophobicity between the two gases and the presence of the donor in the NO experiments. The biological implications of the above results are discussed.
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Affiliation(s)
- Saviana Nedeianu
- Institute of Biophysics, Biological Research Centre Szeged, P.O. Box 521, H-6701 Szeged, Hungary
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Nakagawa K. ESR Spin Probe Investigation of Chain Ordering of a Triglycerol Membrane. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2004. [DOI: 10.1246/bcsj.77.269] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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45
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Trubitsin BV, Tikhonov AN. Determination of a transmembrane pH difference in chloroplasts with a spin label tempamine. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2003; 163:257-269. [PMID: 12914841 DOI: 10.1016/s1090-7807(03)00110-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present a method for measuring the transmembrane pH difference (deltapH=pHin-pHout) in chloroplasts with a spin label TEMPAMINE (4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl) accumulating inside the thylakoids in response to generation of deltapH. Experiments with chloroplasts suspended in the media of different osmolarity demonstrated that most of TEMPAMINE (TA) molecules taken up by chloroplasts were localized in the bulk of the thylakoid lumen. The DeltapH value was determined from the relationship deltapH=lg([H+]in/[H+]out) approximately equal to lg(Cin/Cout), where Cin and Cout are the concentrations of TA inside and outside the thylakoids, respectively. To quantify the internal concentration Cin, we used the threshold nature of the concentration-dependent broadening of the EPR signal from TA. It was demonstrated that spin-exchange interactions between TA molecules caused an observable broadening of the signal only when the concentration of TA exceeded the threshold level, [TA]theta approximately 2.0-2.2mM. The concentration dependencies of the signal parameters (the peak-to-peak amplitude, App, and the linewidth, deltaHpp) were described within a model of the non-homogeneous broadening of an unresolved hyperfine multiplet from the protons of TA molecule. If the concentration of TA inside the thylakoids went beyond the threshold level, the spin-exchange broadening of the EPR signal was accompanied by a reversible decrease in the signal height (parameter deltaA). By measuring the signal behavior at different levels of microwave power, we were able to discriminate between the line broadening effects caused by concentrating TA molecules inside the thylakoids or the light-induced changes in the concentration of oxygen. We developed a general algorithm for determination of the deltapH value and the internal volume of thylakoids, Vin, from the non-linear dependence of parameter deltaA on the concentration C0 of TA in a chloroplast suspension. Advantages of this method are: (i) it avoids the use of a broadening agent; (ii) it allows the internal volume of thylakoids to be evaluated; and (iii) the concentrations of TA used to measure the deltapH are below the range of concentrations that could cause the uncoupling electron transport to ATP synthesis in chloroplasts. Results of our measurements are consistent with the literature data on deltapH determinations by other methods.
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Affiliation(s)
- Boris V Trubitsin
- Department of Biophysics, Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119992, Russia
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46
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Nakagawa K. Diffusion Coefficient and Relaxation Time of Aliphatic Spin Probes in a Unique Triglyceride Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2003; 19:5078-5082. [PMID: 27676262 DOI: 10.1021/la026813d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The molecular dynamics of aliphatic spin probes in a unique triglyceride membrane were investigated by continuous wave electron paramagnetic resonance (CW EPR) and saturation recovery spectroscopic methods. Rotational diffusion coefficients (R⊥ and R∥) obtained by a slow-motional EPR spectral simulation for 7-doxylstearic acid (7-DSA), 12-doxylstearic acid (12-DSA), and 16-doxylstearic acid (16-DSA) in the membrane at various temperatures were obtained. The activation energies calculated using R⊥ values for 7-, 12-, and 16-DSA in the membrane were 19 ± 0.9, 24 ± 1.2, and 37 ± 1.8 kJ/mol, respectively. The higher activation energy implies that the perpendicular motion of 16-DSA is more sensitive to temperature. As the nitroxide group of the spin probe was moved further down the stearic chain, electron spin-lattice relaxation times (T1e) became shorter. The shorter T1e indicates more flexibility around the probe moiety. Also, T1e for the DSAs became shorter when the temperature increased. The values of T1e obtained were consistent with perpendicular diffusion coefficients. In addition, no significant difference in T1e between the H2O and the D2O solutions was observed for the different DSAs. Therefore, it is concluded that steric effects and the local rotational mobility of the nitroxide moiety influence the T1e's obtained.
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Affiliation(s)
- Kouichi Nakagawa
- RI Research Center, Fukushima Medical University, 1 Hikarigaoka, Fukushima 960-1295, Japan
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47
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Yruela I, Alfonso M, García-Rubio I, Martínez JI, Picorel R, Alonso PJ. Spin label electron paramagnetic resonance study in thylakoid membranes from a new herbicide-resistant D1 mutant from soybean cell cultures deficient in fatty acid desaturation. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1515:55-63. [PMID: 11597352 DOI: 10.1016/s0005-2736(01)00393-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The effect of fatty acid desaturation on lipid fluidity in thylakoid membranes isolated from the STR7 mutant was investigated by electron paramagnetic resonance (EPR) using spin label probes. The spectra of both 5- and 16-n-doxylstearic acid probes were measured as a function of the temperature between 10 and 305 K and compared to those of the wild type. This complete thermal evolution provides a wider picture of the dynamics. The spectra of the 5-n-doxylstearic acid probe as well as their temperature evolution were identical in both STR7 mutant and wild type thylakoids. However, differences were found with the 16-n-doxylstearic acid probe at temperatures between 230 and 305 K. The differences in the thermal evolution of the EPR spectra can be interpreted as a 5-10 K shift toward higher temperatures of the probe motional rates in the STR7 mutant as compared with that in the wild type. At temperatures below 230 K no differences were observed. The results indicated that the lipid motion in the outermost region of the thylakoids is the same in the STR7 mutant as in the wild type while the fluidity in the inner region of the STR7 mutant membrane decreases. Our data point out a picture of the STR7 thylakoid membrane in which the lipid motion is slower most probably as a consequence of fatty acid desaturation deficiency.
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Affiliation(s)
- I Yruela
- Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas, Zaragoza, Spain.
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