Nanotechnology with S-layer proteins.

The cross-fertilization of biology, chemistry, material sciences, and solid-state physics is opening up a great variety of new opportunities for innovation in nanosciences. One of the key challenges is the technological utilization of self-assembly systems wherein molecules spontaneously associate under equilibrium conditions into reproducible supramolecular aggregates. The attractiveness of such processes lies in their capability to build uniform, ultrasmall functional units and the possibility of exploiting such structures at meso- and macroscopic scale for life and nonlife science applications.

Reaction of ferrous lactoperoxidase with hydrogen peroxide and dioxygen: an anaerobic stopped-flow study.

Lactoperoxidase (LPO) is found in mucosal surfaces and exocrine secretions including milk, tears, and saliva and has physiological significance in antimicrobial defense which involves (pseudo-)halide oxidation. LPO compound III (a ferrous-dioxygen complex) is known to be formed rapidly by an excess of hydrogen peroxide and could participate in the observed catalase-like activity of LPO. The present anaerobic stopped-flow kinetic analysis was performed in order to elucidate the catalytic mechanism of LPO and the kinetics of compound III formation by probing the reactivity of ferrous LPO with hydrogen peroxide and molecular oxygen.

Kinetics of interconversion of redox intermediates of lactoperoxidase, eosinophil peroxidase and myeloperoxidase.

Myeloperoxidase, eosinophil peroxidase and lactoperoxidase are heme-containing oxidoreductases, which undergo a series of redox reactions. Though sharing functional and structural homology, reflecting their phylogenetic origin, differences are observed regarding their spectral features, substrate specificities, redox properties and kinetics of interconversion of the relevant redox intermediates ferric and ferrous peroxidase, compound I, compound II and compound III. Depending on substrate availability, these heme enzymes path through the halogenation cycle and/or the peroxidase cycle and/or act as poor (pseudo-) catalases.

Behaviour of bisphenol A (BPA), 4-nonylphenol (4-NP) and 4-nonylphenol ethoxylates (4-NP1EO, 4-NP2EO) in oxidative water treatment processes.

Endocrine disrupting chemicals (EDCs) such as natural and synthetic hormones or industrial chemicals can adversely affect the endocrine system at very low concentrations. As such substances can be present in raw water used for drinking-water production, they potentially pose a health risk to humans. In this study laboratory tests were performed to determine removal efficiencies of selected oxidative drinking water treatment processes, namely ozonation (1.

Stress in recombinant protein producing yeasts.

It is well established today that heterologous overexpression of proteins is connected with different stress reactions. The expression of a foreign protein at a high level may either directly limit other cellular processes by competing for their substrates, or indirectly interfere with metabolism, if their manufacture is blocked, thus inducing a stress reaction of the cell. Especially the unfolded protein response (UPR) in Saccharomyces cerevisiae (as well as some other yeasts) is well documented, and its role for the limitation of expression levels is discussed.

Determination of the carbon deficiency in the flame ionization detector response of long-chain fatty acid methyl esters and dicarboxylic acid dimethyl esters.

Carbon deficiencies (CDs) of long-chain fatty acid methyl esters (FAMEs) and dicarboxylic acid dimethyl esters (DDMEs), which lead to decreased response in a flame ionization detection (FID) system, were determined by using full responding hydrocarbons (heptadecane, eicosane and alpha-cholestane) as references. For saturated FAMEs ranging from C12 to C22 and for DDMEs ranging from C4 to C10, CDs between 1.3+/-0.

Influence of the unusual covalent adduct on the kinetics and formation of radical intermediates in synechocystis catalase peroxidase: a stopped-flow and EPR characterization of the MET275, TYR249, and ARG439 variants.

Catalase-peroxidases (KatGs) are heme peroxidases with a catalatic activity comparable to monofunctional catalases. They contain an unusual covalent distal side adduct with the side chains of Trp(122), Tyr(249), and Met(275) (Synechocysis KatG numbering). The known crystal structures suggest that Tyr(249) and Met(275) could be within hydrogen-bonding distance to Arg(439).

Ancestral gene fusion in cellobiose dehydrogenases reflects a specific evolution of GMC oxidoreductases in fungi.

Cellobiose dehydrogenases (CDHs) are extracellular hemoflavoenzymes that are thought to be involved in the degradation of two of the most abundant biopolymers in the biosphere, cellulose and lignin. To date, these enzymes, consisting of a cytochrome domain and a flavin domain, have been detected and sequenced exclusively in the kingdom of fungi. Independent phylogenetic analyses of two distinct domains of CDH genes reveal that they evolved in parallel as fused genes.

A fuzzy logic approach to control anaerobic digestion.

One of the goals of the EU-Project AMONCO (Advanced Prediction, Monitoring and Controlling of Anaerobic Digestion Process Behaviour towards Biogas Usage in Fuel Cells) is to create a control tool for the anaerobic digestion process, which predicts the volumetric organic loading rate (Bv) for the next day, to obtain a high biogas quality and production. The biogas should contain a high methane concentration (over 50%) and a low concentration of components toxic for fuel cells, e.g.

Modelling of the production of gaseous by-products in anaerobic digestion.

Goal of the EU-Project AMONCO (Advanced Prediction, Monitoring and Controlling of Anaerobic Digestion Processes Behaviour towards Biogas Usage in Fuel Cells) is demonstration of the practical use of biogas in fuel cells. The right precondition is a biogas quality which fits into the fuel cells tolerances. Therefore the mission of the workgroup Environmental biotechnology is to control anaerobic digestion in a way that production of potential harmful by-products for fuel cells is reduced.

Optimized biogas-fermentation by neural network control.

In this work several feed-forward back-propagation neural networks (FFBP) were trained in order to model, and subsequently control, methane production in anaerobic digesters. To produce data for the training of the neural nets, four anaerobic continuous stirred tank reactors (CSTR) were operated in steady-state conditions at organic loading rates (Br) of about 2 kg x m(-3) x d(-1) chemical oxygen demand (COD), and disturbed by pulse-like increase of the organic loading rate. For the pulses additional carbon sources were added to the basic feed (surplus- and primary sludge) to simulate cofermentation and to increase the COD.

Kinetics of oxygen binding to ferrous myeloperoxidase.

Myeloperoxidase (MPO), which is involved in host defence and inflammation, is a unique peroxidase in having a globin-like standard reduction potential of the ferric/ferrous couple. Intravacuolar and exogenous MPO released from stimulated neutrophils has been shown to exist in the oxyferrous form, called compound III. To investigate the reactivity of ferrous MPO with molecular oxygen, a stopped-flow kinetic analysis was performed.

Purification and characterization of a beta-xylosidase from potatoes (Solanum tuberosum).

Potatoes are a cheap and easily available source for the preparation of beta 1,2-xylosidase. The soluble enzyme was purified from potato tubers by ammonium sulfate precipitation, hydrophobic interaction chromatography, affinity gel blue chromatography, ion exchange and size exclusion chromatography yielding a glycoprotein with a molecular weight of 39-40 kDa, an isoelectric point of 5.1 and a typical plant N-glycosylation pattern.

Adjunct starter properties affect characteristic features of Swiss-type cheeses.

A large number of microorganisms, both starter microorganisms and non-starter lactic acid bacteria originating from the base milk, or from various contamination sources during cheese manufacture, is associated with cheese ripening and the formation of flavour, texture and aroma. Under controlled conditions, Emmental and Bergkäse, a Gruyère-type cheese variety, were produced from pasteurised milk with standard starters and defined strains of facultatively heterofermentative lactobacilli (FHL), and partly with addition of a defined mixture of enterococci. Lactobacillus casei subsp.

Feeding laying hens seal blubber oil: effects on egg yolk incorporation, stereospecific distribution of omega-3 fatty acids, and sensory aspects.

Seventy-two 26-wk-old Single Comb White Leghorn laying hens were randomly assigned to 36 cages (2 per cage) in a 3-orthogonal 4 x 4 latin square, with the fourth row suppressed, to assess the effect of feeding refined seal blubber oil (SBO, containing 22.2% omega-3 fatty acids) on the fatty acid composition and position in the egg yolk lipids. The experiment was conducted over a period of 9 wk.

The plant microtubule-associated protein AtMAP65-3/PLE is essential for cytokinetic phragmoplast function.

Directional cell expansion in interphase and nuclear and cell division in M-phase are mediated by four microtubule arrays, three of which are unique to plants: the interphase array, the preprophase band, and the phragmoplast. The plant microtubule-associated protein MAP65 has been identified as a key structural component in these arrays. The Arabidopsis genome has nine MAP65 genes, and here we show that one, AtMAP65-3/PLE, locates only to the mitotic arrays and is essential for cytokinesis.

Highly robust lipid membranes on crystalline S-layer supports investigated by electrochemical impedance spectroscopy.

In the present work, S-layer supported lipid membranes formed by a modified Langmuir-Blodgett technique were investigated by electrochemical impedance spectroscopy (EIS). Basically two intermediate hydrophilic supports for phospholipid- (DPhyPC) and bipolar tetraetherlipid- (MPL from Thermoplasma acidophilum) membranes have been applied: first, the S-layer protein SbpA isolated from Bacillus sphaericus CCM 2177 recrystallized onto a gold electrode; and second, as a reference support, an S-layer ultrafiltration membrane (SUM), which consists of a microfiltration membrane (MFM) with deposited S-layer carrying cell wall fragments. The electrochemical properties and the stability of DPhyPC and MPL membranes were found to depend on the used support.

Monitoring of a paper mill wastewater treatment plant using UV/VIS spectroscopy.

A submersible UV/VIS spectrometer was used to monitor a paper mill wastewater treatment plant. It utilises the UV/VIS range (200-750 nm) for simultaneous measurement of COD, filtered COD, TSS and nitrate with just a single instrument. The instrument measures in-situ, directly in the process.

Effects of gene dosage, promoters, and substrates on unfolded protein stress of recombinant Pichia pastoris.

The expression of heterologous proteins may exert severe stress on the host cells at different levels. Depending on the specific features of the product, different steps may be rate-limiting. For the secretion of recombinant proteins from yeast cells, folding and disulfide bond formation were identified as rate-limiting in several cases and the induction of the chaperone BiP (binding protein) is described.

Wolbachia transfer from Rhagoletis cerasi to Drosophila simulans: investigating the outcomes of host-symbiont coevolution.

Wolbachia is an endosymbiont of diverse arthropod lineages that can induce various alterations of host reproduction for its own benefice. Cytoplasmic incompatibility (CI) is the most common phenomenon, which results in embryonic lethality when males that bear Wolbachia are mated with females that do not. In the cherry fruit fly, Rhagoletis cerasi, Wolbachia seems to be responsible for previously reported patterns of incompatibility between populations.

Characterisation of cellobiose dehydrogenases from the white-rot fungi Trametes pubescens and Trametes villosa.

Cellobiose dehydrogenase (CDH) is an extracellular haemoflavoenzyme that is produced by a number of wood-degrading and phytopathogenic fungi and it has a proposed role in the early events of lignocellulose degradation and wood colonisation. In the presence of a suitable electron acceptor, e.g.

Direct conversion of ferrous myeloperoxidase to compound II by hydrogen peroxide: an anaerobic stopped-flow study.

Myeloperoxidase (MPO) is one of the essential components of the antimicrobial systems of polymorphonuclear neutrophils. It is unique in having a globin-like standard reduction potential of the ferric/ferrous couple. Here, it is shown that ferrous MPO heterolytically cleaves hydrogen peroxide forming water and oxyferryl MPO (compound II).

Simulation of subsurface flow constructed wetlands--results and further research needs.

Simulation of constructed wetlands has two main tasks: to obtain a better understanding of the processes in constructed wetlands, and to check and optimise existing design criteria. This paper shows simulation results for two indoor pilot-scale constructed wetlands for wastewater and surface water treatment respectively. The results presented and discussed are mainly focussed on the hydraulic behaviour of the constructed wetland systems.

Evaluation of substrate clogging processes in vertical flow constructed wetlands.

Substrate clogging is by far the biggest operational problem of vertical flow constructed wetlands. The term "substrate clogging" summarises several processes which lead to reduction of the infiltration capacity at the substrate surface. The lower infiltration rate causes a reduced oxygen supply and further leads to a rapid failure of the treatment performance.

Rhizosphere characteristics of the arsenic hyperaccumulator Pteris vittata L. and monitoring of phytoremoval efficiency.

Recently discovered As-hyperaccumulator ferns hold promise for phytoremediation of As-polluted soils. We investigated changes in the rhizosphere characteristics of Pteris vittata (Chinese Brake fern) relevant for its use in phytoextraction. Plants were grown in rhizoboxes filled with soil containing 2270 mg kg(-1) As.