AMP-dependent phosphite dehydrogenase, a phosphorylating enzyme in dissimilatory phosphite oxidation.

Oxidation of phosphite (HPO) to phosphate (HPO) releases electrons at a very low redox potential (E= -690 mV) which renders phosphite an excellent electron donor for microbial energy metabolism. To date, two pure cultures of strictly anaerobic bacteria have been isolated that run their energy metabolism on the basis of phosphite oxidation, the Gram-negative (DSM 13687) and the Gram-positive (DSM 112739). Here, we describe the key enzyme for dissimilatory phosphite oxidation in these bacteria.

Anaerobic dissimilatory phosphite oxidation, an extremely efficient concept of microbial electron economy.

Phosphite is a stable phosphorus compound that, together with phosphate, made up a substantial part of the total phosphorus content of the prebiotic Earth's crust. Oxidation of phosphite to phosphate releases electrons at an unusually low redox potential (-690 mV at pH 7.0).

Isophthalate:coenzyme A ligase initiates anaerobic degradation of xenobiotic isophthalate.

Background: Environmental contamination from synthetic plastics and their additives is a widespread problem. Phthalate esters are a class of refractory synthetic organic compounds which are widely used in plastics, coatings, and for several industrial applications such as packaging, pharmaceuticals, and/or paints. They are released into the environment during production, use and disposal, and some of them are potential mutagens and carcinogens.

Quantification of archaea-driven freshwater nitrification from single cell to ecosystem levels.

Deep oligotrophic lakes sustain large populations of the class Nitrososphaeria (Thaumarchaeota) in their hypolimnion. They are thought to be the key ammonia oxidizers in this habitat, but their impact on N-cycling in lakes has rarely been quantified. We followed this archaeal population in one of Europe's largest lakes, Lake Constance, for two consecutive years using metagenomics and metatranscriptomics combined with stable isotope-based activity measurements.

gen. nov. sp. nov., a new dissimilatory phosphite-oxidizing anaerobic bacterium isolated from anaerobic sewage sludge.

A new strictly anaerobic bacterium, strain DYL19, was enriched and isolated with phosphite as the sole electron donor and CO as a single carbon source and electron acceptor from anaerobic sewage sludge sampled at a sewage treatment plant in Constance, Germany. It is a Gram-positive, spore-forming, slightly curved, rod-shaped bacterium which oxidizes phosphite to phosphate while reducing CO to biomass and small amounts of acetate. Optimal growth is observed at 30 °C, pH 7.

Pelorhabdus rhamnosifermentans gen. nov., sp. nov., a strictly anaerobic rhamnose degrader from freshwater lake sediment.

A rhamnose-degrading bacterium, strain BoRhaA, was isolated from profundal sediment of Lake Constance in agar dilution series with l-rhamnose as substrate and with a background lawn of Methanospirillum hungatei. The isolated strain was a motile rod that stained Gram positive. Growth was observed within a pH range of 4.

Two Marine Desulfotomaculum spp. of Different Origin are Capable of Utilizing Acetone and Higher Ketones.

Degradation of acetone and higher ketones has been described in detail for aerobic and nitrate-reducing bacteria. Among sulfate-reducing bacteria, degradation of acetone and other ketones is still an uncommon ability and has not been understood completely yet. In the present work, we show that Desulfotomaculum arcticum and Desulfotomaculum geothermicum are able to degrade acetone and butanone.

Activation of short-chain ketones and isopropanol in sulfate-reducing bacteria.

Background: Degradation of acetone by aerobic and nitrate-reducing bacteria can proceed via carboxylation to acetoacetate and subsequent thiolytic cleavage to two acetyl residues. A different strategy was identified in the sulfate-reducing bacterium Desulfococcus biacutus that involves formylation of acetone to 2-hydroxyisobutyryl-CoA.

Results: Utilization of short-chain ketones (acetone, butanone, 2-pentanone and 3-pentanone) and isopropanol by the sulfate reducer Desulfosarcina cetonica was investigated by differential proteome analyses and enzyme assays.

Initiates Degradation of Aniline With the Production of Phenylphosphoamidate and 4-Aminobenzoate as Intermediates Through Synthases and Carboxylases From Different Gene Clusters.

The anaerobic degradation of aniline was studied in the sulfate-reducing bacterium . Our aim was to identify the genes and their proteins that are required for the initial activation of aniline as well as to characterize intermediates of this reaction. Aniline-induced genes were revealed by comparison of the proteomes of grown with different substrates (aniline, 4-aminobenzoate, phenol, and benzoate).

Resorcinol Hydroxylase of Azoarcus anaerobius: Molybdenum Dependence, Activity, and Heterologous Expression.

The obligately anaerobic, denitrifying bacterium Azoarcus anaerobius strain LuFRes1 grows with resorcinol (1,3-dihydroxybenzene) as sole carbon and energy source. Resorcinol is oxidized to hydroxyhydroquinone (1,2,4-trihydroxybenzene) by resorcinol hydroxylase (RH), an inducible membrane-bound enzyme. Sequence comparison places resorcinol hydroxylase into the group of anaerobic molybdopterin oxidoreductases and dimethyl sulfoxide reductase-like enzymes.

Desulfolutivibrio sulfoxidireducens gen. nov., sp. nov., isolated from a pyrite-forming enrichment culture and reclassification of Desulfovibrio sulfodismutans as Desulfolutivibrio sulfodismutans comb. nov.

Two strains of sulfate-reducing bacteria (J.5.4.

Further guidelines for the formation of compound specific and subspecific epithets. A proposal to emend Appendix 9 of the International Code of Nomenclature of Prokaryotes.

We propose emending section A(1)(b) of Appendix 9 of the International Code of Nomenclature of Prokaryotes with further guidelines for the formation of compound specific or subspecific epithets based on localities and epithets based on binomial names of plants or animals.

Use of Greek in the prokaryotic nomenclature: proposal to change Principle 3, Recommendation 6, Rule 7, Rule 65 and Appendix 9 of the International Code of Nomenclature of Prokaryotes.

Principle 3 of the International Code of Nomenclature of Prokaryotes (ICNP) states that the scientific names of all taxa are Latin or latinized words treated as Latin regardless of their origin. They are usually taken from Latin or Greek. Recently we encountered cases where newly proposed names were based on words from Modern Greek that are not derived from words found in the dictionaries of Classical Greek.

Physiological limits to life in anoxic subseafloor sediment.

In subseafloor sediment, microbial cell densities exponentially decrease with depth into the fermentation zone. Here, we address the classical question of 'why are cells dying faster than they are growing?' from the standpoint of physiology. The stoichiometries of fermentative ATP production and consumption in the fermentation zone place bounds on the conversion of old cell biomass into new.

Energy-Conserving Enzyme Systems Active During Syntrophic Acetate Oxidation in the Thermophilic Bacterium .

The thermophilic acetogen uses the Wood-Ljungdahl pathway (WLP) in both directions, either for the production of acetate from various compounds or for the oxidation of acetate in syntrophic cooperation with methanogens. In this study, energy-conserving enzyme systems in were investigated in both metabolic directions. A gene cluster containing a membrane-bound periplasmically oriented formate dehydrogenase directly adjacent to putative menaquinone synthesis genes was identified in the genome.

Microbial degradation of phthalates: biochemistry and environmental implications.

The environmentally relevant xenobiotic esters of phthalic acid (PA), isophthalic acid (IPA) and terephthalic acid (TPA) are produced on a million ton scale annually and are predominantly used as plastic polymers or plasticizers. Degradation by microorganisms is considered as the most effective means of their elimination from the environment and proceeds via hydrolysis to the corresponding PA isomers and alcohols under oxic and anoxic conditions. Further degradation of PA, IPA and TPA differs fundamentally between anaerobic and aerobic microorganisms.

Enzymes involved in phthalate degradation in sulphate-reducing bacteria.

The complete degradation of the xenobiotic and environmentally harmful phthalate esters is initiated by hydrolysis to alcohols and o-phthalate (phthalate) by esterases. While further catabolism of phthalate has been studied in aerobic and denitrifying microorganisms, the degradation in obligately anaerobic bacteria has remained obscure. Here, we demonstrate a previously overseen growth of the δ-proteobacterium Desulfosarcina cetonica with phthalate/sulphate as only carbon and energy sources.

The use of Greek and Latin prepositions and prefixes in compound names: proposed emendation of Appendix 9 of the International Code of Nomenclature of Prokaryotes.

Part A of Appendix 9 - Orthography of the International Code of Nomenclature of Prokaryotes regulates the formation of compound generic names and specific epithets derived by combining two or more words or word elements of Latin and/or Greek origin, using the word stems and connecting vowels (-o- or -i-) following word elements derived from Greek and Latin, respectively. The rules given and the exceptions listed are suitable for substantives (nouns) and adjectives used as word elements, but not for prepositions and prefixes. Therefore, we propose a non-retroactive modification of Appendix 9 so that the guidelines given in Part A apply only to compound names that include a noun or an adjective in a non-final position.

Alternative Pathways of Acetogenic Ethanol and Methanol Degradation in the Thermophilic Anaerobe .

Growth of the anaerobic thermophile with methanol, ethanol, ethanolamine, and acetate was investigated in axenic cultures and in syntrophic cultures with . Microcompartment genes were identified in the genome, and presence of microcompartments was confirmed by transmission electron microscopy and proteome analysis. These genes were expressed only during growth with ethanolamine.

Pyrite formation from FeS and HS is mediated through microbial redox activity.

The exergonic reaction of FeS with HS to form FeS (pyrite) and H was postulated to have operated as an early form of energy metabolism on primordial Earth. Since the Archean, sedimentary pyrite formation has played a major role in the global iron and sulfur cycles, with direct impact on the redox chemistry of the atmosphere. However, the mechanism of sedimentary pyrite formation is still being debated.

Naming classes of prokaryotes based on the rules of Latin grammar.

Recently a proposal was published to unify Rules 7, 8 and 9 of the International Code of Nomenclature of Prokaryotes. Based on this proposal, all names of taxa above the rank of genus must be in the feminine gender, the plural number. For the rank of class, this proposal contravenes Principle 3 of the Code, which states that the scientific names of all taxa are treated as Latin.

Anaerobic degradation of xenobiotic isophthalate by the fermenting bacterium Syntrophorhabdus aromaticivorans.

Syntrophorhabdus aromaticivorans is a syntrophically fermenting bacterium that can degrade isophthalate (3-carboxybenzoate). It is a xenobiotic compound which has accumulated in the environment for more than 50 years due to its global industrial usage and can cause negative effects on the environment. Isophthalate degradation by the strictly anaerobic S.

Formate and Hydrogen as Electron Shuttles in Terminal Fermentations in an Oligotrophic Freshwater Lake Sediment.

The energetic situation of terminal fermentations in methanogenesis was analyzed by pool size determinations in sediment cores taken in the oligotrophic Lake Constance, Germany. Distribution profiles of fermentation intermediates and products were measured at three different water depths (2, 10, and 80 m). Methane concentrations were constant below 10 cm of sediment depth.