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.

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.

Four Molybdenum-Dependent Steroid C-25 Hydroxylases: Heterologous Overproduction, Role in Steroid Degradation, and Application for 25-Hydroxyvitamin D Synthesis.

Side chain-containing steroids are ubiquitous constituents of biological membranes that are persistent to biodegradation. Aerobic, steroid-degrading bacteria employ oxygenases for isoprenoid side chain and tetracyclic steran ring cleavage. In contrast, a Mo-containing steroid C-25 dehydrogenase (S25DH) of the dimethyl sulfoxide (DMSO) reductase family catalyzes the oxygen-independent hydroxylation of tertiary C-25 in the anaerobic, cholesterol-degrading bacterium Its genome contains eight paralogous genes encoding active site α-subunits of putative S25DH-like proteins.

Evolution of a xenobiotic degradation pathway: formation and capture of the labile phthaloyl-CoA intermediate during anaerobic phthalate degradation.

Xenobiotic phthalates are industrially produced on the annual million ton scale. The oxygen-independent enzymatic reactions involved in anaerobic phthalate degradation have only recently been elucidated. In vitro assays suggested that phthalate is first activated to phthaloyl-CoA followed by decarboxylation to benzoyl-CoA.

Reversibility of citrate synthase allows autotrophic growth of a thermophilic bacterium.

Biological inorganic carbon fixation proceeds through a number of fundamentally different autotrophic pathways that are defined by specific key enzymatic reactions. Detection of the enzymatic genes in (meta)genomes is widely used to estimate the contribution of individual organisms or communities to primary production. Here we show that the sulfur-reducing anaerobic deltaproteobacterium is capable of both acetate oxidation and autotrophic carbon fixation, with the tricarboxylic acid cycle operating either in the oxidative or reductive direction, respectively.

Promiscuous Defluorinating Enoyl-CoA Hydratases/Hydrolases Allow for Complete Anaerobic Degradation of 2-Fluorobenzoate.

Biodegradation of the environmentally hazardous fluoroaromatics has mainly been associated with oxygenase-dependent defluorination reactions. Only very recently a novel mode of oxygen-independent defluorination was identified for the complete degradation of -substituted fluoroaromatics in the denitrifying : a promiscuous class I benzoyl-coenzyme A (BzCoA) reductase (BCR) catalyzed the ATP-dependent defluorination of 4-F-BzCoA to BzCoA. Here, we studied the unknown enzymatic defluorination during the complete degradation of 2-F-benzoate to CO and HF.

A patchwork pathway for oxygenase-independent degradation of side chain containing steroids.

The denitrifying betaproteobacterium Sterolibacterium denitrificans serves as model organism for studying the oxygen-independent degradation of cholesterol. Here, we demonstrate its capability of degrading various globally abundant side chain containing zoo-, phyto- and mycosterols. We provide the complete genome that empowered an integrated genomics/proteomics/metabolomics approach, accompanied by the characterization of a characteristic enzyme of steroid side chain degradation.

ATP-Dependent C-F Bond Cleavage Allows the Complete Degradation of 4-Fluoroaromatics without Oxygen.

Unlabelled: Complete biodegradation of the abundant and persistent fluoroaromatics requires enzymatic cleavage of an arylic C-F bond, probably the most stable single bond of a biodegradable organic molecule. While in aerobic microorganisms defluorination of fluoroaromatics is initiated by oxygenases, arylic C-F bond cleavage has never been observed in the absence of oxygen. Here, an oxygen-independent enzymatic aryl fluoride bond cleavage is described during the complete degradation of 4-fluorobenzoate or 4-fluorotoluene to CO2 and HF in the denitrifying Thauera aromatica: the ATP-dependent defluorination of 4-fluorobenzoyl-coenzyme A (4-F-BzCoA) to benzoyl-coenzyme A (BzCoA) and HF, catalyzed by class I BzCoA reductase (BCR).

An unusual strategy for the anoxic biodegradation of phthalate.

In the past two decades, the study of oxygen-independent degradation of widely abundant aromatic compounds in anaerobic bacteria has revealed numerous unprecedented enzymatic principles. Surprisingly, the organisms, metabolites and enzymes involved in the degradation of o-phthalate (1,2-dicarboxybenzene), mainly derived from phthalate esters that are annually produced at the million ton scale, are sparsely known. Here, we demonstrate a previously unknown capacity of complete phthalate degradation in established aromatic compound-degrading, denitrifying model organisms of the genera Thauera, Azoarcus and 'Aromatoleum'.

Enzymes involved in a novel anaerobic cyclohexane carboxylic acid degradation pathway.

The anaerobic degradation of cyclohexane carboxylic acid (CHC) has so far been studied only in Rhodopseudomonas palustris, in which CHC is activated to cyclohexanoyl coenzyme A (cyclohexanoyl-CoA [CHCoA]) and then dehydrogenated to cyclohex-1-ene-1-carboxyl-CoA (CHeneCoA). This intermediate is further degraded by reactions of the R. palustris-specific benzoyl-CoA degradation pathway of aromatic compounds.

Evaluation of an ultrasound-guided technique for central venous access via the internal jugular vein in 493 patients.

Ultrasound guidance for percutaneous puncture of the internal jugular vein provides many advantages over the classic landmark-guided technique, particularly in complicated cases (e.g. thrombocytopenia, obesity, dyspnea).

[A standardized technique for ultrasound controlled placement of a central venous catheter].

To reduce the rate of complications and failures in central venous catheterisation a technique for ultrasonically controlled puncture of the internal jugular vein was standardised. The puncture procedure, including the application of local anaesthesia, is continuously observed and guided by real-time ultrasound. Imaging, control and practising of the puncture are described and discussed.

[Change in liver size caused by antitubercular combination therapy].

In 23 patients undergoing antituberculous combination treatment, an ultrasonographic study of the dimensions of the liver was carried out every two weeks for the first two to three months of treatment. Starting with the fourth to sixth week on the therapeutic regimen, significant increases in the width of the left, and the length of the right liver lobes amounting to an average of 1 cm (11%) were established. Differences in the time course of changes in liver size were not to be found, neither in connection with adverse reactions, nor as a function of sex.

[Reproducibility of sonographic measurements in the follow-up of liver size].

Liver diameters determined in various standardised sonographic section planes are investigated concerning their reproductiveness and validity in controls of liver size. The most reliable parameters proved to be the length in the posterior axillary line, the maximised depths of the right lobe at the portal branching and at the venous confluence, and the maximised length, breadth and thickness of the left lobe. Accuracy is improved by mean values calculated from the diameters of the adjacent longitudinal sections in the axillary lines and of the maximised depth sections of the right lobe.

[Sonographic diagnosis of arterial occlusive disease].

In 32 patients presenting symptoms of arterial occlusive disease, 50 lower limbs were examined both by ultrasonography and angiography (DSA). Sonography was performed using a 5.0 MHz real-time scanner; common femoral, superficial femoral and deep femoral arteries were visualized continuously in whole length.

[Blood flow through different tissues under clonidine in rabbits (author's transl)].

The effect of i.v. administered clonidine on the blood flow through different tissues was investigated in six rabbits which had been anaesthetized with NembutalR.