A Peroxygenase from Chaetomium globosum Catalyzes the Selective Oxygenation of Testosterone

Unspecific peroxygenases (UPO, EC 1.11.2.1) secreted by fungi open an efficient way to selectively oxyfunctionalize diverse organic substrates, including less‐activated hydrocarbons, by transferring peroxide‐borne oxygen. We investigated a cell‐free approach to incorporate epoxy and hydroxyl functionalities directly into the bulky molecule testosterone by a novel unspecific peroxygenase (UPO) that is produced by the ascomycetous fungus Chaetomium globosum in a complex medium rich in carbon and nitrogen. Purification by fast protein liquid chromatography revealed two enzyme fractions with the same molecular mass (36 kDa) and with specific activity of 4.4 to 12 U mg^?1. Although the well‐known UPOs of Agrocybe aegerita (AaeUPO) and Marasmius rotula (MroUPO) failed to convert testosterone in a comparative study, the UPO of C. globosum (CglUPO) accepted testosterone as substrate and converted it with total turnover number (TTN) of up to 7000 into two oxygenated products: the 4,5‐epoxide of testosterone in β‐configuration and 16α‐hydroxytestosterone. The reaction performed on a 100 mg scale resulted in the formation of about 90 % of the epoxide and 10 % of the hydroxylation product, both of which could be isolated with purities above 96 %. Thus, CglUPO is a promising biocatalyst for the oxyfunctionalization of bulky steroids and it will be a useful tool for the synthesis of pharmaceutically relevant steroidal molecules.     

Measuring process consistency: implications for reducing softwaredefects

In this paper, an empirical study that links software process consistency with product defects is reported. Various measurement issues such as validity, reliability, and other challenges in measuring process consistency at the project level are discussed. A measurement scale for software process consistency is introduced. An empirical study that uses this scale to measure consistency in achieving the CMM goal questions in various key process areas (KPAs) in 45 projects at a leading software vendor is reported. The results of this analysis indicate that consistent adoption of practices specified in the CMM is associated with a lower number of defects. Even a relatively modest improvement in the consistency of implementing these practices is associated with a significant reduction in field defects     

Influence of Ca ions and temperature on the corrosion behavior of WC–Co hardmetals in alkaline solutions

The effect of temperature and Ca ions on the corrosion behavior of hardmetals was investigated in 0.1 M NaOH and 0.05 M Ca(OH)₂ alkaline electrolytes using impedance spectroscopy, potentiodynamic polarization and surface analytical techniques. It was found that calcium containing alkaline solutions efficiently decrease the anodic currents up to 5 times by forming a calcium containing deposit on the top of the WC–Co hardmetal surface, which remains stable even at higher temperatures (40 °C and 60 °C). This positive influence of Ca ions is predominant under polarization in the range from 0 to +0.85 V (Ag/AgCl) but is not apparent under OCP conditions. In NaOH, however, the corrosion resistance strongly decreases at higher temperatures as compared with the room temperature. At the slightly elevated temperature in 0.1 M NaOH the Co binder phase loses its passivity and is almost completely washed out of the compound material. A WC skeleton remains on the surface and hence the ductility in the hardmetal is lost. In the end, the material could completely fail under such operating conditions. Also the Ni alloyed binder loses its strong passivation ability at the elevated temperatures.     

Control of antioxidant beer activity by the mashing process

Beer is considered to be a good source of antioxidants. The composition and the quantity of the antioxidant compounds depend not only on the qualities of the raw materials, but also on the technology processes. Barley and malt represent the main source of antioxidant compounds in beer and the contribution of the hop antioxidants is lower. The influence of the mashing process on the antioxidant activity and polyphenol concentration is crucial. The antioxidant state of the sweet wort and the hopped wort are dependent on the technology processes and the raw materials used. The spontaneous sorption of polyphenols onto wort dregs and the polymerization of catechin and epicatechin lead to decreasing concentrations of individual polyphenols in the final beer. Two methods, based on electron spin resonance were used to determine antioxidant activity. These were the DPPH (2,2‐diphenyl‐1‐picryl‐hydrazyl) assay and the ‘lag time’ assay using free radical spin‐trapping agent PBN (N‐tert‐butyl‐α‐phenylnitrone). HPLC with CoulArray detection was used to measure the concentration of the individual polyphenols. This study focused on the antioxidant compounds and on the correlation of their concentrations with the values of total antioxidant activity depending on the mashing process. A good correlation was found between the decline in the concentrations of DPPH (expressed as ARA2) and concentrations of catechin and epicatechin (in sweet wort samples R² = 0.970, R² = 0.961, respectively, and in hopped wort samples R² = 0.949, R² = 0.956 respectively). Copyright © 2012 The Institute of Brewing & Distilling     

Impact of breakfast on daily energy intake - an analysis of absolute versus relative breakfast calories

Objective  

The role of breakfast energy in total daily energy intake is a matter of debate. Acute feeding experiments demonstrated that high breakfast energy leads to greater overall intake supported by cross-sectional data of a free-living population. On the other hand, a large intraindividual analysis has indicated that a high proportion of breakfast to overall intake is associated with lower daily energy intake. To evaluate these apparently contradictory results in greater detail both ways of analysis were applied to the same data set of dietary records.     

Synthesis and Metabolic Fate of 4-Methylthiouridine in Bacterial tRNA

Ribonucleic acid (RNA) is central to many life processes and, to fulfill its function, it has a substantial chemical variety in its building blocks. Enzymatic thiolation of uridine introduces 4-thiouridine (s⁴U) into many bacterial transfer RNAs (tRNAs), which is used as a sensor for UV radiation. A similar modified nucleoside, 2-thiocytidine, was recently found to be sulfur-methylated especially in bacteria exposed to antibiotics and simple methylating reagents. Herein, we report the synthesis of 4-methylthiouridine (ms⁴U) and confirm its presence and additional formation under stress in Escherichia coli. We used the synthetic ms⁴U for isotope dilution mass spectrometry and compared its abundance to other reported tRNA damage products. In addition, we applied sophisticated stable-isotope pulse chase studies (NAIL-MS) and showed its AlkB-independent removal in vivo. Our findings reveal the complex nature of bacterial RNA damage repair.     

Use of proximity effect in iridium-gold superconducting phase transition thermometers

We have studied the proximity effect in bilayers of thin films of iridium covered by gold. These structures were evaporated onto sapphire single crystals for use as phase transition thermometers in cryogenic particle detectors. By varying the thicknesses of the iridium and gold layers, we achieved critical temperatures as low as 33 mK. The critical temperature of the bilayers is lower than predicted by the theory of de Gennes-Werthamer, but adding a free parameter to the theory allows good agreement. The transitions of the bilayers typically had widths of a few mK, with the narrowest reaching 0.2 mK, and were always sharper than those of pure iridium films evaporated simultaneously.     

RDS/peripherin gene mutations are frequent causes of central retinal dystrophies

Patients from 76 independent families with various forms of mostly central retinal dystrophies were screened for mutations in the RDS/peripherin gene by means of SSCP analysis and direct DNA sequencing. Two nonsense mutations (Gln239ter, Tyr285ter), five missense mutations (Arg172Trp, Lys197Glu, Gly208Asp, Trp246Arg, Ser289Leu), and one single base insertion (Gly208insG), heterozygous in all cases, were detected. Only one of these mutations, Arg172Trp, has been reported previously. Cosegregation of the mutation with the disease phenotype could be established in selected families. Other missense mutations were excluded from a panel of 55-75 control subjects. The patients showed remarkable variation in phenotype and disease expression not only between cases with different mutations but also between affected members of the same family. This study indicates that RDS/peripherin mutations are a frequent cause of various types of central retinal dystrophies and that the RDS/peripherin gene exhibits a broad spectrum of allelic mutations. Comparative analysis of known mutations allowed us to hypothesise that the deleterious effect of RDS/peripherin gene mutations is the result of different molecular mechanisms.