Search Results - (Author, Cooperation:E. Wolf)

2012-01-10

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Cocaine/*pharmacology

2018-04-20

Institute of Physics (IOP)

1367-2630

Physics

2018-09-12

Institute of Physics (IOP)

1367-2630

Physics

2014-07-22

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Binding Sites ; Cell Line, Tumor ; Down-Regulation/*genetics ; E-Box Elements/genetics ; Gene Expression Regulation, Neoplastic/*genetics ; Genes, myc/*genetics ; Humans ; Kruppel-Like Transcription Factors/metabolism ; Mice ; Neoplasms/*genetics ; Nuclear Proteins/metabolism ; Promoter Regions, Genetic/genetics ; Protein Inhibitors of Activated STAT/metabolism ; Proto-Oncogene Proteins c-myc/genetics/metabolism ; RNA Polymerase II/metabolism ; *Transcriptome ; Up-Regulation/*genetics

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

In Escherichia coli, SoxS, MarA and Rob form a closely related subset of the AraC/XylS family of positive regulators, sharing ∼42% amino acid sequence identity over the length of SoxS and the ability to activate transcription of a common set of target genes that provide resistance to redox-cycling compounds and antibiotics. On the basis of its ∼43% amino acid sequence identity with SoxS, MarA and Rob, TetD, encoded by transposon Tn10, appears to be a fourth member of the subset. However, although its expression has been shown to be negatively regulated by TetC and not inducible by tetracycline, the physiological function of TetD is unknown. Accordingly, in the work presented here, we initiate a molecular characterization of TetD. We show that expression of TetD activates transcription of a subset of the SoxS/MarA/Rob regulon genes and confers resistance to redox-cycling compounds and antibiotics. We show that mutations in the putative TetD binding site of a TetD-activatable promoter and a mutation in the protein's N-terminal DNA recognition helix interfere with transcription activation, thereby indicating that TetD directly activates target gene transcription. Finally, we show that TetD, like SoxS and MarA, is intrinsically unstable; however, unlike SoxS and MarA, TetD is not degraded by Lon or any of the cell's known cytoplasmic ATP-dependent proteases. Thus, we conclude that TetD is a bona fide member of the SoxS/MarA/Rob subfamily of positive regulators.

Electronic Resource

1365-2958

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

In Escherichia coli, the SoxRS regulon confers resistance to redox-cycling compounds, and the Mar regulon provides a defence against multiple antibiotics. The response regulators, SoxS and MarA, are synthesized de novo in response to their inducing signals and directly activate transcription of a common set of target genes. Although the mechanisms of transcription activation by SoxS and MarA have been well studied, little is known about how the systems are shut-off once the inducing stress has subsided, except that de novo synthesis of the regulators is known to cease almost immediately. Here, we induced the SoxRS regulon and determined that, upon removal of the inducer, expression of the regulon's genes quickly returns to the preinduced level. This rapid shut-off indicates that the system is reset by an active process. We found that SoxS is unstable and infer that SoxS degradation is responsible for the rapid return of the system to the ground state upon removal of the inducing signal. We also found that MarA is unstable and that the instability of both proteins is intrinsic and unregulated. We used null mutations of protease genes to identify the proteases involved in the degradation of SoxS and MarA. Among single protease mutations, only lon mutations increased the half-life of SoxS and MarA. In addition, SoxS appeared to be nearly completely stable in a lon ftsH double mutant. Using hexahistidine tags placed at the respective ends of the activators, we found that access to the amino-terminus is essential for the proteolytic degradation.

Electronic Resource

article

2006

Test ; Sekundarstufe I ; Fischer-Technik ; Unterrichtsmaterial ; Arbeitslehre ; Modellversuch ; Technikunterricht ; Batterie ; Baukasten ; Herstellung

Unterricht Arbeit + Technik, Bd. 8 (2006) H. 29, S. 20-23, 0941-536X

1438-8987

German

Literaturangaben

article

1991

Didaktische Grundlageninformation ; Unterrichtsziel ; Unterrichtsmaterial ; Technikunterricht ; Bewertung

Zeitschrift für Technik im Unterricht, (1991) H. 60, S. 5-9, 0342-6254

German

Literaturangaben

article

1983

Bildung ; Einstellung (Psy) ; Automatisierung ; Ingenieurwissenschaft ; Technikunterricht ; Technik

Schule - Wirtschaft, (1983) H. 21, S. 67-78

German

article

1989

Hauptschule ; Schüler ; Lernen ; Erfahrungsorientiertes Lernen ; Handlungsorientierung ; Sachinformation ; Unterrichtsmaterial ; Fachdidaktik ; Technikunterricht ; Berufsorientierung ; Berufsvorbereitung ; Berufswahl ; Konzeption

Didaktik der Berufs- und Arbeitswelt, Bd. 8 (1989) H. 2-3, S. 32-36, 0721-5932

German

article

1995

Sekundarstufe I ; Gesamtschule ; Gruppenunterricht ; Kursunterricht ; Fächerübergreifender Unterricht ; Fachunterricht ; Erfahrungsbericht

Anschub : das Forum für schulische Umweltbildung in Berlin, (1995) H. 1, S. 8-10

German

article

1994

Allgemein bildende Schule ; Sekundarstufe I ; CIM (Computer Integrated Manufacturing) ; Projekt ; Computergestützte Numerische Steuerung ; Steuerungs- und Regelungstechnik ; Technikunterricht ; Qualifikation ; Schlüsselqualifikation ; Berufsschule ; Definition

Zeitschrift für Technik im Unterricht, Bd. 19 (1994) H. 71, S. 41-46, 0342-6254

German

Literaturangaben

article

1981

Unterrichtseinheit ; Unterrichtsmaterial ; Arbeitslehre ; Maschinenbau ; Technikunterricht ; Unfallverhütung ; Arbeitssicherheit

Arbeiten + lernen, Bd. 3 (1981) H. 13, S. 35-39, 0172-7338

German

article

1981

Kind ; Schule ; Didaktische Grundlageninformation ; Arbeitslehre ; Technikunterricht ; Sicherheitserziehung ; Unfall ; Unfallverhütung ; Arbeitsrecht ; Arbeit ; Arbeitssicherheit ; Didaktische Erörterung

Arbeiten + lernen, Bd. 3 (1981) H. 13, S. 6-11, 0172-7338

German

article

1990

Biologie ; Meer ; Wasser ; Meeresströmung ; Ozean ; Temperatur ; Ökologie ; Wirkung ; Pazifischer Ozean

Biologie in unserer Zeit, Bd. 20 (1990) H. 6, S. 289-296, 0045-205X

German

Literaturangaben

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

Scanning tunneling spectroscopy (STS) capable of measuring the local density of states dI/dV=G(V,x,y) correlated with the topography z(x,y) is implemented on a PC/AT computer system. An algorithm using dimensional decoupling and recursive linking is incorporated in a compact C-language code to achieve flexible and sophisticated STS control. Data acquisition and processing methods which provide the local density of states G(V,x,y,s) at different tip heights s in registry with z(x,y) are described. Examples of novel low-temperature experiments are given to show the capabilities of this implementation of STS.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We report on the spatially dependent enhanced etch rate of SiO2 in a CF4 planar reactive ion etcher due to the presence of the compounds GaAs or InP, or the single elements Ti, V, Nb, Ta, Cr, Mo, W, Ni, Pd, Pt, Cu, Ag, Au, Al, Ga, In, or Ge. The etch rate enhancement is maximum immediately adjacent to the source of the material and decreases nonlinearly with increasing distance away from the source of the material. Of the materials studied, the largest local etch rate increase was due to the element Ni (65% increase), followed closely by the elements In (57%) and Ga (43%) and the compounds InP (55%) and GaAs (40%). The lateral range of the effect extends 5 to 30 mm away from the material depending on the element or compound. Material interaction, possibly a catalized reaction, with the CF4 plasma reactants and lateral transport to provide an increased local concentration of fluorine at the SiO2 surface is a preliminary suggestion for the observed etch rate increase.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Electromigration failure of a series-parallel configuration of aluminum interconnects overlayed on tungsten contacts was measured using a novel multiple lognormal analysis. The analysis examined early failure mechanisms and allowed rapid determination of electromigration parameters on a statistically large number of junctions. The primary failure mode of these stuctures was complete migration of Al off of the W pads. This work suggested that Al/W metallizations, with a large number of series contacts, are prone to short mean time to failures.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The proximity-Josephson effect (PJE) is a powerful general method of determining the symmetry of the pair wave function in exotic superconductors. The method is simple and relatively insensitive to the surface condition of the sample. A superconducting probe (S) of known pairing symmetry (typically Nb or Ta) is brought into contact with the sample (N). Observations and arguments based on the de Gennes boundary condition at the NS interface both indicate formation of a local, proximity-induced superconducting region of depth ξ in the sample (N) under the probe. The induced pairs have the same symmetry as those of S. The expected pair-phase dependence of the coupling energy between the pairs in N and S leads to a Josephson current Ic(T), which may be observed up to a junction critical temperature T* which is typically ∼0.8 of the Tc of S. When the measurement temperature falls below the bulk Tc of N (the exotic superconductor), a pair wave function of possibly different symmetry forms in the bulk of N and overlaps the induced pair wave function near the probe. Weak interactions between the induced and bulk pairs occur. In the case of UBe13 contacted with a Ta tip, the interaction weakly suppresses the induced pairs [which determine Ic(T)] leading to a reduction of the Josephson current at T〈Tc. This observation of a negative S-wave proximity effect in superconducting UBe13, in good agreement with a Ginzburg–Landau analysis, is strong evidence for triplet pairing in this heavy fermion compound.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

We describe a compact scanning tunneling microscope using piezoelectric bimorph elements to achieve a large scanning area of 20 μm2 at 4.2 K. This instrument provides inherent temperature compensation, compatibility with a high magnetic field environment, and a novel means of rough sample–tip (z) adjustment.

Electronic Resource