The bioenergetic role of dioxygen and the terminal oxidase(s) in cyanobacteria

AbstractOwing to the release of 13 largely or totally sequenced cyanobacterial genomes (see http://www.kazusa.or.jp/cyano and www.jgi.doe.gov/), it is now possible to critically assess and compare the most neglected aspect of cyanobacterial physiology, i.e., cyanobacterial respiration, also on the grounds of pure molecular biology (gene sequences). While there is little doubt that cyanobacteria (blue-green algae) do form the largest, most diversified and in both evolutionary and ecological respects most significant group of (micro)organisms on our earth, and that what renders our blue planet earth to what it is, viz. the O2-containing atmosphere, dates back to the oxygenic photosynthetic activity of primordial cyanobacteria about 3.2×109 years ago, there is still an amazing lack of knowledge on the second half of bioenergetic oxygen metabolism in cyanobacteria, on (aerobic) respiration. Thus, the purpose of this review is threefold: (1) to point out the unprecedented role of the cyanobacteria for maintaining the delicate steady state of our terrestrial biosphere and atmosphere through a major contribution to the poising of oxygenic photosynthesis against aerobic respiration (“the global biological oxygen cycle”); (2) to briefly highlight the membrane-bound electron-transport assemblies of respiration and photosynthesis in the unique two-membrane system of cyanobacteria (comprising cytoplasmic membrane and intracytoplasmic or thylakoid membranes, without obvious anastomoses between them); and (3) to critically compare the (deduced) amino acid sequences of the multitude of hypothetical terminal oxidases in the nine fully sequenced cyanobacterial species plus four additional species where at least the terminal oxidases were sequenced. These will then be compared with sequences of other proton-pumping haem–copper oxidases, with special emphasis on possible mechanisms of electron and proton transfer

Ceruloplasmin is an endogenous inhibitor of myeloperoxidase

Myeloperoxidase is a neutrophil enzyme that promotes oxidative stress in numerous inflammatory pathologies. It uses hydrogen peroxide to catalyze the production of strong oxidants including chlorine bleach and free radicals. A physiological defense against the inappropriate action of this enzyme has yet to be identified. We found that myeloperoxidase oxidized 75% of the ascorbate in plasma from ceruloplasmin knock-out mice, but there was no significant loss in plasma from wild type animals. When myeloperoxidase was added to human plasma it became bound to other proteins and was reversibly inhibited. Ceruloplasmin was the predominant protein associated with myeloperoxidase. When the purified proteins were mixed, they became strongly but reversibly associated. Ceruloplasmin was a potent inhibitor of purified myeloperoxidase, inhibiting production of hypochlorous acid by 50% at 25 nM

Peroxidasin protein expression and enzymatic activity in metastatic melanoma cell lines are associated with invasive potential

Peroxidasin, a heme peroxidase, has been shown to play a role in cancer progression. mRNA expression has been reported to be upregulated in metastatic melanoma cell lines and connected to the invasive phenotype, but little is known about how peroxidasin acts in cancer cells. We have analyzed peroxidasin protein expression and activity in eight metastatic melanoma cell lines using an ELISA developed with an in-house peroxidasin binding protein. RNAseq data analysis confirmed high peroxidasin mRNA expression in the five cell lines classified as invasive and low expression in the three non-invasive cell lines. Protein levels of peroxidasin were higher in the cell lines with an invasive phenotype. Active peroxidasin was secreted to the cell culture medium, where it accumulated over time, and peroxidasin protein levels in the medium were also much higher in invasive than non-invasive cell lines. The only well-established physiological role of peroxidasin is in the formation of a sulfilimine bond, which cross-links collagen IV in basement membranes via catalyzed oxidation of bromide to hypobromous acid. We found that peroxidasin secreted from melanoma cells formed sulfilimine bonds in uncross-linked collagen IV, confirming peroxidasin activity and hypobromous acid formation. Moreover, 3-bromotyrosine, a stable product of hypobromous acid reacting with tyrosine residues, was detected in invasive melanoma cells, substantiating that their expression of peroxidasin generates hypobromous acid, and showing that it does not exclusively react with collagen IV, but also with other biomolecules

Hypochlorous acid inactivates myeloperoxidase inside phagocytosing neutrophils

When neutrophils phagocytose bacteria, they release myeloperoxidase (MPO) into phagosomes to catalyse the conversion of superoxide to the potent antimicrobial oxidant hypochlorous acid (HOCl). Here we show that within neutrophils, MPO is inactivated by HOCl. In this study, we aimed to identify the effects of HOCl on the structure and function of MPO, and determine the enzyme’s susceptibility to oxidative inactivation during phagocytosis. When hydrogen peroxide was added to a neutrophil granule extract containing chloride, MPO activity was rapidly lost in a HOCl-dependent reaction. With high concentrations of hydrogen peroxide, western blotting demonstrated that MPO was both fragmented and converted to high molecular weight aggregates. Using the purified enzyme, we showed that HOCl generated by MPO inactivated the enzyme by destroying its prosthetic heme groups and releasing iron. MPO protein was additionally modified by forming high molecular weight aggregates. Before inactivation occurred, MPO chlorinated itself to convert most of its amine groups to dichloramines. When human neutrophils phagocytosed Staphylococcus aureus, they released MPO that was largely inactivated in a process that required production of superoxide. Enzyme inactivation occurred inside neutrophils because it was not blocked when extracellular HOCl was scavenged with methionine. The inactivated enzyme contained a chlorinated tyrosine residue, establishing that it had reacted with HOCl. Our results demonstrate that MPO will substantially inactivate itself during phagocytosis, which may limit oxidant production inside phagosomes. Other neutrophil proteins are also likely to be inactivated. The chloramines formed on neutrophil proteins may contribute to the bactericidal milieu of the phagosome

Sustainability in production and logistics : from product design to product recovery

Die Verschmutzung von Luft, Boden und der Meere nimmt aufgrund der steigenden Schadstoffemissionen, des zunehmenden Energie- und Ressourcenverbrauchs sowie Mülls stetig zu. Um diesen Negativtrend zu stoppen, ist eine Änderung der derzeitigen Produktionsphilosophie notwendig. Bei einer solchen werden erstens umweltfreundlichere Produkte erzeugt und zweitens ein Product-Recovery betrieben. Um diese Entwicklung zu unterstützen, werden in dieser Arbeit alle Phasen eines Green Supply Chain Managements vorgestellt. Das Management einer „grünen“ Lieferkette berücksichtigt den Umweltfaktor während eines gesamten Produktlebenszyklus. Es beginnt beim Produktdesign, wobei auf eine umweltverträgliche Materialauswahl, Ressourcen- und Müllminimierung sowie auf Demontage- und Recoveryfähigkeit geachtet wird. Ressourcen, die zugekauft werden, müssen von möglichst „grünen“ Zulieferern bezogen werden. Im Produktionsprozess ist auf umweltschonende Verfahren, insbesondere auf die Reduktion von Schadstoffemissionen zu achten. In Folge sind die Produkte umweltschonend zu den Konsumenten zu transportieren. Da die Green Supply Chain eine geschlossene Lieferkette ist, werden die gebrauchten Produkte eingesammelt und einem Product-Recovery unterzogen. Es ist darauf zu achten, dass der Rücktransport der gebrauchten Produkte die Umweltvorteile des Recovery nicht kompensiert. Im Product-Recovery stehen die Möglichkeiten der Reparatur, des Refurbishings, Remanufacturings, der Kannibalisierung und des Recyclings zur Verfügung. Nur Teile, die keinesfalls wieder verwendet werden können, werden schlussendlich entsorgt. Zu jeder Phase der „grünen“ Lieferkette werden entweder Guidelines, hierarchische Entscheidungsmodelle oder Optimierungsmodelle präsentiert, welche als Anregungen zur Umsetzung eines Green-SCM dienen sollen. Zusätzlich wird durch Beispiele gezeigt, wie etablierte Unternehmen „grüne“ Praktiken umsetzen.The pollution of air, soil, and oceans increases due to rising levels of greenhouse gas emissions, energy and resource consumption, and waste. Changing the current production philosophy is necessary to stop this negative trend. Hence, eco-friendly products should be produced and product recovery pursued. In order to support this development all stages of a Green Supply Chain Management are introduced in this thesis. The management of a “green” supply chain incorporates the environmental factor during the entire product life cycle. It starts with the product design. A “green” design aims for an ecologically sensitive selection of materials, the minimization of resources and waste, and the ability to disassemble and recover the used product. External resources must be purchased from environmentally benign suppliers. Within the production process, pollution emissions must be minimized. Subsequently, the end-product must be delivered to the consumers in an eco-friendly way, which means minimal fuel consumption and emissions. As the Green Supply Chain is a closed-loop supply chain, used products have to be collected and recovered. Thereby it is important that the backhauling does not compensate the positive effects of the product recovery. Repair, refurbishing, remanufacturing, cannibalization, and recycling are possibilities within the product recovery management. Only those parts, which do not fit into any recovery category, are finally disposed. For each stage of the “green” supply chain guidelines, hierarchic decision models, or optimization models are presented in the thesis to encourage an implementation of Green-SCM. Additionally, examples are shown to demonstrate how well established companies realize “green” practices.Sabrina PaumannAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassungen in engl. und dt. SpracheGraz, Univ., Masterarb., 2015 D1008

Sustainability in production and logistics : from product design to product recovery

Die Verschmutzung von Luft, Boden und der Meere nimmt aufgrund der steigenden Schadstoffemissionen, des zunehmenden Energie- und Ressourcenverbrauchs sowie Mülls stetig zu. Um diesen Negativtrend zu stoppen, ist eine Änderung der derzeitigen Produktionsphilosophie notwendig. Bei einer solchen werden erstens umweltfreundlichere Produkte erzeugt und zweitens ein Product-Recovery betrieben. Um diese Entwicklung zu unterstützen, werden in dieser Arbeit alle Phasen eines Green Supply Chain Managements vorgestellt. Das Management einer „grünen“ Lieferkette berücksichtigt den Umweltfaktor während eines gesamten Produktlebenszyklus. Es beginnt beim Produktdesign, wobei auf eine umweltverträgliche Materialauswahl, Ressourcen- und Müllminimierung sowie auf Demontage- und Recoveryfähigkeit geachtet wird. Ressourcen, die zugekauft werden, müssen von möglichst „grünen“ Zulieferern bezogen werden. Im Produktionsprozess ist auf umweltschonende Verfahren, insbesondere auf die Reduktion von Schadstoffemissionen zu achten. In Folge sind die Produkte umweltschonend zu den Konsumenten zu transportieren. Da die Green Supply Chain eine geschlossene Lieferkette ist, werden die gebrauchten Produkte eingesammelt und einem Product-Recovery unterzogen. Es ist darauf zu achten, dass der Rücktransport der gebrauchten Produkte die Umweltvorteile des Recovery nicht kompensiert. Im Product-Recovery stehen die Möglichkeiten der Reparatur, des Refurbishings, Remanufacturings, der Kannibalisierung und des Recyclings zur Verfügung. Nur Teile, die keinesfalls wieder verwendet werden können, werden schlussendlich entsorgt. Zu jeder Phase der „grünen“ Lieferkette werden entweder Guidelines, hierarchische Entscheidungsmodelle oder Optimierungsmodelle präsentiert, welche als Anregungen zur Umsetzung eines Green-SCM dienen sollen. Zusätzlich wird durch Beispiele gezeigt, wie etablierte Unternehmen „grüne“ Praktiken umsetzen.The pollution of air, soil, and oceans increases due to rising levels of greenhouse gas emissions, energy and resource consumption, and waste. Changing the current production philosophy is necessary to stop this negative trend. Hence, eco-friendly products should be produced and product recovery pursued. In order to support this development all stages of a Green Supply Chain Management are introduced in this thesis. The management of a “green” supply chain incorporates the environmental factor during the entire product life cycle. It starts with the product design. A “green” design aims for an ecologically sensitive selection of materials, the minimization of resources and waste, and the ability to disassemble and recover the used product. External resources must be purchased from environmentally benign suppliers. Within the production process, pollution emissions must be minimized. Subsequently, the end-product must be delivered to the consumers in an eco-friendly way, which means minimal fuel consumption and emissions. As the Green Supply Chain is a closed-loop supply chain, used products have to be collected and recovered. Thereby it is important that the backhauling does not compensate the positive effects of the product recovery. Repair, refurbishing, remanufacturing, cannibalization, and recycling are possibilities within the product recovery management. Only those parts, which do not fit into any recovery category, are finally disposed. For each stage of the “green” supply chain guidelines, hierarchic decision models, or optimization models are presented in the thesis to encourage an implementation of Green-SCM. Additionally, examples are shown to demonstrate how well established companies realize “green” practices.Sabrina PaumannAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassungen in engl. und dt. SpracheGraz, Univ., Masterarb., 2015 D1008