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SummaryOxygen respiration originated in evolution within the prokaryotic kingdom and was acquired by eukaryotes later via endosymbiosis. Prokaryotes are divided into the domains of Bacteria and Archaea. The latter represent the so called third phylogenetic domain and are not only characterized by their unusual extremophilic life styles, but also by a variety of molecular pecularities including their...
SummaryThe group of Gram-positive bacteria is a major phylum of prokaryotes, including several typical saprophytic aerobes. Their respiratory chains are apparently similar to those of eukaryotic mitochondria, but in several points are different from them. The respiratory chain of Gram-positives, like many bacteria, contains branched electron transfer pathways, usually 1-3 heme-Cu oxidases, but SoxB-type...
SummaryThe microaerophilic, human gastro-intestinal pathogens, Campylobacter jejuni and Helicobacter pylori are closely related phylogentically, yet distinct in some major aspects of their physiology, especially with regard to electron transport. C. jejuni is a more versatile and metabolically active pathogen, with a complete citri-acid cycle, and a complex and highly branched respiratory chain allowing...
SummaryAcetic acid bacteria are obligate aerobes, and well known to have a strong ability to oxidize ethanol, sugars or sugar alcohols to produce the corresponding sugar acids. These oxidation reactions of sugars and alcohols in acetic acid bacteria are uniquely carried out by primary dehydrogenases located in the periplasmic side of the cytoplasmic membrane and linked to the terminal ubiquinol oxidase(s)...
SummaryNitrogen fixation allows a diverse array of bacteria, either free-living in the environment or in symbiosis with plants, to grow in areas where fixed N is deficient. This confers them a large advantage over their non-N2 fixing competitors. Nevertheless, N2 fixation is an energy-demanding process, so that energy-generating respiration is oftentimes closely associated with efficient N2 fixing...
SummaryThis chapter deals with the oxidation of ammonia (NH3 + 1.5 O2→ HNO2+H2O as a source of reducing power in the chemolithrotrophic bacterium Nitrosomonas europaea. Direct knowledge of the enzymes involved together with the sequence of the genome reveal core elements of a redox system unique to oxidation of ammonia to nitrite which feeds into a more traditional bacterial electron transport/terminal...
SummaryMethanotrophs are a unique bacterial group characterized by the ability to utilize methane as a sole carbon and energy source. Methanotrophs oxidize methane to CO2 via a series of two electron steps with methanol, formaldehyde, and formate as intermediates. In addition to the known growth substrates methanotrophs will oxidize a variety of multi-carbon compounds, molecular hydrogen, and ammonia...
SummaryRespiratory reactions involving inorganic nitrogen species provide a rich variety of systems with which to study bacterial bioenergetics and biological chemistry. These respiratory reactions encompass the reduction of nitrate, nitrite, nitric oxide and nitrous oxide; in all cases catalysis involves redox chemistry that takes place at metal centers. These catalytic metal centers include mono-nuclear...
SummaryPossible mechanisms by which energy may be conserved from the aerobic oxidation of ferrous iron byThiobaccillus ferrooxidans are discussed. A rationale based on a consideration of the thermodynamic constraints of the system and an analysis of sequence information of the respiratory cytochrome oxidase is applied. Limitations are imposed on possible models and it is suggested thatTb.ferrooxidans...
SummaryCertain anaerobic prokaryotes grow by oxidative phosphorylation with elemental sulfur as the terminal electron acceptor instead of O2 (sulfur respiration or anaerobic respiration with sulfur). The mechanism of sulfur respiration has been investigated in great detail only inWolinella (W.) succinogenes. This ε-proteobacterium uses, as terminal electron acceptor, polysulfide which is formed abiotically...
SummaryHydrogen respiration can be considered either as (i) the oxidation of H2 to H+, with the electrons released being channeled into a membrane-bound, respiratory electron transport chain or (ii) as the reduction of H+ to H2 in the terminal reaction of an anaerobic, low-potential electron transport system. In both cases, the redox reaction involving H2 is catalyzed by a hydrogenase enzyme (H2ase)...
SummaryCyanobacterial respiration has some unique features. Cyanobacteria contain two independent respiratory chains, one in the cytoplasmic membrane and one in the intracytoplasmic membranes (also called thylakoids). The latter is intimately linked with the photosynthetic electron transport chain and some components, e.g. the quinone pool, the cytochromeb6f complex, and cytochrome...
SummaryThe respiratory and photosynthetic electron transport chains of the two facultative phototrophsRhodobacter(Rb.) sphaeroides andRb.Capsulatus are arranged in such a way to be spatially segregated in separate regions of the internal membrane system (CM and ICM). The CM part contains the majority of the oxidative redox components which are therefore in redox non-equilibrium with most of the photochemical...
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