Fungal aerobic reductive dechlorination of ethyl 2-chloroacetoacetate by Saccharomyces cerevisiae: mechanism of a novel type of microbial dehalogenation

Saccharomyces cerevisiae reduces the beta-keto ester ethyl 2-chloroacetoacetate to the respective chiral cis- and trans-beta-hydroxy esters. In the course of chiral reduction, competing dehalogenation of the xenobiotic substrate to ethyl acetoacetate occurs, in a reaction mediated by cytosolic glutathione (GSH). Mechanistically, the dechlorination is a novel type of glutathione-dependent dehalogenation catalysed by an as yet unidentified glutathione-dependent dehalogenase. The first step consists of a nucleophilic replacement of the chloride substituent by glutathione. In the subsequent enzyme-catalysed step, a second glutathione molecule liberates the dehalogenation product by thiolytic attack at the thioether bridge, resulting in a net transfer of two electrons to the substrate and in the formation of glutathione disulfide (GSSG). Being effective under aerobic conditions and catalysed by a fungus, this reductive dechlorination of an aliphatic substrate is an outstanding example of a novel, glutathione-mediated microbial dehalogenation.     

Comparison of SeaWiFS measurements of the Moon with the U.S. Geological Survey lunar model

The Sea-Viewing Wide-Field-of-View Sensor (SeaWiFS) has made monthly observations of the Moon since 1997. Using 66 monthly measurements, the SeaWiFS calibration team has developed a correction for the instrument's on-orbit response changes. Concurrently, a lunar irradiance model has been developed by the U.S. Geological Survey (USGS) from extensive Earth-based observations of the Moon. The lunar irradiances measured by SeaWiFS are compared with the USGS model. The comparison shows essentially identical response histories for SeaWiFS, with differences from the model of less than 0.05% per thousand days in the long-term trends. From the SeaWiFS experience we have learned that it is important to view the entire lunar image at a constant phase angle from measurement to measurement and to understand, as best as possible, the size of each lunar image. However, a constant phase angle is not required for using the USGS model. With a long-term satellite lunar data set it is possible to determine instrument changes at a quality level approximating that from the USGS lunar model. However, early in a mission, when the dependence on factors such as phase and libration cannot be adequately determined from satellite measurements alone, the USGS model is critical to an understanding of trends in instruments that use the Moon for calibration. This is the case for SeaWiFS.     

Unter welchen Voraussetzungen bewähren sich Korrosionsschutzauskleidungen aus Fluorkunststoff-Folien

Under what conditions are anticorrosion liners made from fluorinated plastic film effective ? Equipment lined with fluorinated plastics is nowadays making a major contribution to the solution of difficult materials problems. If such equipment is to be used successfully, it is essential that its manufacturer is familiar with the specific properties of the lining materials and takes them into account in the design and production of the equipment. However, it is just as important for the operator to adjust to the material when operating the plant. On the basis of many years of experience, the most important problems associated with loose liners made from polytetrafluoroethylene (PTFE) – viz. leakproofness and permeability of the liner, flange system, dimensional stability towards vacuum, handling, and installation – are indicated and possible solutions stated.     

Verfahrenstechnik für den Umweltschutz

Industrial process engineering and environmental protection . Industrial process engineering involves not only the realization of chemical-physical processes but also the optimization of the economics of a plant and the minimization of environment pollution. Since the incorporation of additional facilities in a process for the reduction of emission has been brought to a high technical standard in recent years, more and more attention will now be directed to achieving a high selectivity in favor of the product in the chemical reaction by suitable process control. It is shown with the aid of schematically represented mass balances and cost diagrams that emission can be reduced by process engineering optimization of a process, leading to a decrease in both the costs incurred from environmental pollution and the costs for the preventative measures taken.     

Entschwefelung von Eisenschmelzen über die Schlackenphase unter oxidierenden Bedingungen

Darstellung und Eigenschaften der festen Oxidsulfide. Das Oxid-Sulfid-System Fe–FeO_n–CaO–CaS–FeS. Schwefelverteilung zwischen dicalciumsilicatgesättigten Schlacken und der Eisenphase. Sulfide und Oxidsulfide in erstarrten dicalciumsilicatgesättigten Schlacken. Metallurgische Schlußfolgerungen.     

Planung von Korrosionsschutzarbeiten bei Neubauten

Planning of Works Involving Prevention of Corrosion in New Buildings Like all other constructional procedures the works involving prevention of corrosion must also be carefully planned within the constructional programme. This is possible if during planning, the specialist for the prevention of corrosion obtains an insight of the plan along with all the individual objects. Consequently, the specialist determines the preventive measures like derusting, coating or metallizing for each of the objects. Choice of the systems for the prevention of corrosion is dependent on the amount of stresses which the object concerned has to endure later. In his orders and contracts the customer should exactly specify the services required.     

Classification of rheumatoid joint inflammation based on laser imaging

We describe a classification system for a novel imaging method for arthritic finger joints. The basis of this system is a laser imaging technique which is sensitive to the optical characteristics of finger joint tissue. From the laser images acquired at baseline and follow-up, finger joints can automatically be classified according to whether the inflammatory status has improved or worsened. To perform the classification task, various linear and kernel-based systems were implemented and their performances were compared. Based on the results presented in this paper, we conclude that the laser-based imaging permits a reliable classification of pathological finger joints, making it a sensitive method for detecting arthritic changes.