Analysis of the hypoxia-induced ADH2 promoter of the respiratory yeast Pichia stipitis reveals a new mechanism for sensing of oxygen limitation in yeast

We introduced a reporter gene system into Pichia stipitis using the gene for the artificial green fluorescent protein (GFP), variant yEGFP. This system was used to analyse hypoxia-dependent PsADH2 regulation. Reporter gene activity was only found under oxygen limitation on a fermentable carbon source. The promoter was not induced by oxygen limitation in the Crabtree-positive yeast Saccharomyces cerevisiae. Promoter deletions revealed that a region of 15 bp contained the essential site for hypoxic induction. This motif was different from the known hypoxia response elements of S. cerevisiae but showed some similarity to the mammalian HIF-1 binding site. Electrophoretic mobility shift assays demonstrated specific protein binding to this region under oxygen limitation. Similar to the S. cerevisiae heme sensor system, the promoter was induced by Co(2+). Cyanide was not able to mimic the effect of oxygen limitation. The activation mechanism of PsADH2 also, in this respect, has similarities to the mammalian HIF-1 system, which is inducible by Co(2+) but not by cyanide. Thus, the very first promoter analysis in P. stipitis revealed a hitherto unknown mechanism of oxygen sensing in yeast.     

Rhizopus oligosporus and yeast co-cultivation during barley tempeh fermentation--nutritional impact and real-time PCR quantification of fungal growth dynamics

Barley tempeh was produced by fermenting barley kernels with Rhizopus oligosporus. The potential of the yeasts Saccharomyces cerevisiae (three strains), S. boulardii (one strain), Pichia anomala (one strain) and Kluyveromyces lactis (one strain) to grow together with R. oligosporus during barley tempeh fermentation was evaluated. All yeast strains grew during the fermentation and even during cold storage of tempeh (P<0.01). The growth of yeasts slightly increased the ergosterol contents, but did not influence amino acid contents and compositions, and did not reduce phytate contents. Slight increases of vitamins B(6) and niacinamide, and slight decreases of B(1) and biotin were observed. Quantification of fungal growth is difficult during mixed species fermentations because ergosterol is found in all fungal species, and colony-forming-unit (cfu) estimations are not reliable for R. oligosporus and other sporulating fungi. Therefore, we developed a quantitative real-time PCR method for individually quantifying S. cerevisiae and R. oligosporus growth in barley tempeh. The PCR results were highly correlated with the ergosterol content of R. oligosporus and with the number of cfu of S. cerevisiae. Thus, real-time PCR is a rapid and selective method to quantify yeasts and R. oligosporus during mixed species fermentation of inhomogenous substrate such as barley tempeh.     

功能性衬料的静电性质

探讨了不同纺织品结构和后整理对用于防风、防水、透气的功能服的衬料静电性质的影响.亲水性整理的功能性衬料不仅能较好地控制汗液的排放,而且可以更好地亲近皮肤,也有附加的有关防静电的性质.只有亲水性的衬料可以避免明显的静电荷,疏水的面料做不到.然而,亲水面料不能自动提供好的静电性质,一些没有达到防静电最小要求的例子已经证明了这一说法.     

Neuromuscular blockade by IgG antibodies from patients with Guillain-Barré syndrome: a macro-patch-clamp study

Guillain-Barré syndrome (GBS) is often associated with serum antibodies to glycoconjugates such as GM1 and GQ1b. The pathogenic role of these antibodies and other serum factors has not yet been clarified. We have investigated the effect of serum, plasma filtrate, and highly purified IgG and IgM from 10 patients with typical GBS on motor nerve terminals in the mouse hemidiaphragm. Quantal endplate currents were recorded by means of a perfused macro-patch-clamp electrode. The plasma filtrate of all GBS patients led to a 5- to 20-fold reduction of evoked quantal release within 7 to 15 minutes of continuous superfusion. In 4 patients, the amplitudes of single quanta were clearly reduced (by 10-66% of control values), indicating an additional postsynaptic action. Blocking effects could be reversed to a variable degree within 15 to 18 minutes after washout. Purified IgG was as effective as native serum, whereas a purified GBS IgM fraction did not block transmission. Sera from convalescent patients and IgG from healthy subjects were without blocking effect. The effects were complement independent and there was no link to the presence (in 6 patients) or absence (in 4 patients) of detectable antibodies to GM1 or GQ1b. In GBS, antibodies to an undetermined antigen depress the presynaptic transmitter release and, in some cases, the activation of postsynaptic channels. We suggest that weakness in the acute stage of GBS may be caused in part by circulating antibodies.     

Beitrag zum Seigerungsverhalten des Phosphors in reinen untereutektoidischen Eisen-Kohlenstoff-Legierungen

Erschmelzung von Eisen-Kohlenstoff-Phosphor-Legierungen mit 0,02 bis 0,60% C und 0,02 bis 0,6% P im Vakuum-Induktionsofen. Schnelle Abkühlung der Schmelze in der wassergekühlten Kupferkokille und langsame Abkühlung im Al₂O₃-Tiegel. Mikroskopische Untersuchungen, Messungen mit der Elektronenstrahl-Mikrosonde und Mikrohärte-bestimmungen an Proben im Gußzustand und rd. 85% kaltverformt nach Glühungen bei 800, 900 und 1060 °C von 1 bis 168 h Dauer. Ermittlung der Erstarrungsform und der Phosphorseigerung zwischen Dendriten und Restschmelze in Abhängigkeit von Phosphor- und Kohlenstoffgehalt, der Erstarrungsgeschwindigkeit, der Kaltverformung und der Wärmebehandlung.     

Organelle-targeted nanocarriers: specific delivery of liposomal ceramide to mitochondria enhances its cytotoxicity in vitro and in vivo

To further increase the therapeutic activity of drugs known to act on intracellular target sites, in vivo drug delivery approaches must actively mediate the specific delivery of drug molecules to the subcellular site of action. We show here that surface modification of nanocarriers with mitochondriotropic triphenylphosphonium cations facilitates the efficient subcellular delivery of a model drug to mitochondria of mammalian cells and improves its activity in vitro and in vivo.     

Radon and thoron progeny integrated measurement based on high-voltage sampling

For the purpose of directly measuring radon and thoron progeny concentrations simultaneously, an unattended battery-operated progeny measurement (UBPM) device, which samples aerosol particles in an electric field, was improved by adopting two different thickness aluminum foils for alpha particles discriminating. The equations for the calculation of the results were derived, and a series of calibration experiments and comparison tests were carried out in the potential alpha energy concentration calibration chamber in BfS Berlin and the HMGU experimental thoron house, respectively. Results show that the calibration coefficients are stable in different levels of radon and thoron progeny. The lower level detection limits of the device for radon and thoron progeny concentration are 1.22 and 0.14 Bq m^?3, respectively, for three months exposure. The instrument proved to be independent from environmental conditions in ordinary living room conditions (humidity <65% RH, aerosol particle concentration >1500 cm^?1). Comparison results show that the measurement results of the UBPM device are comparable with the reference instrument and suitable for long-term radon and thoron survey in dwellings.     

Physiological requirements for growth and competitiveness of Dekkera bruxellensis under oxygen-limited or anaerobic conditions

The effect of glucose and oxygen limitation on the growth and fermentation performances of Dekkera bruxellensis was investigated in order to understand which factors favour its propagation in ethanol or wine plants. Although D. bruxellensis has been described as a facultative anaerobe, no growth was observed in mineral medium under complete anaerobiosis while growth was retarded under severe oxygen limitation. In a continuous culture with no gas inflow, glucose was not completely consumed, most probably due to oxygen limitation. When an air/nitrogen mixture (O₂‐content ca. 5%) was sparged to the culture, growth became glucose‐limited. In co‐cultivations with Saccharomyces cerevisiae, ethanol yields/g consumed sugar were not affected by the co‐cultures as compared to the pure cultures. However, different population responses were observed in both systems. In oxygen‐limited cultivation, glucose was depleted within 24 h after challenging with S. cerevisiae and both yeast populations were maintained at a stable level. In contrast, the S. cerevisiae population constantly decreased to about 1% of its initial cell number in the sparged glucose‐limited fermentation, whereas the D. bruxellensis population remained constant. To identify the requirements of D. bruxellensis for anaerobic growth, the yeast was cultivated in several nitrogen sources and with the addition of amino acids. Yeast extract and most of the supplied amino acids supported anaerobic growth, which points towards a higher nutrient demand for D. bruxellensis compared to S. cerevisiae in anaerobic conditions. Copyright © 2012 John Wiley & Sons, Ltd.