Martin Luther University of Halle-Wittenberg

About: Martin Luther University of Halle-Wittenberg is a education organization based out in Halle, Germany. It is known for research contribution in the topics: Population & Liquid crystal. The organization has 20232 authors who have published 38773 publications receiving 965004 citations. The organization is also known as: MLU & University of Wittenberg.

Physical carbon-sequestration mechanisms under special consideration of soil wettability

Abstract: The protective impact of aggregation on microbial degradation through separation has been described frequently, especially for biotically formed aggregates. However, to date little information exists on the effects of organic-matter (OM) quantity and OM quality on physical protection, i.e., reduced degradability by microorganisms caused by physical factors. In the present paper, we hypothesize that soil wettability, which is significantly influenced by OM, may act as a key factor for OM stabilization as it controls the microbial accessibility for water, nutrients, and oxygen in three-phase systems like soil. Based on this hypothesis, the first objective is to evaluate new findings on the organization of organo-mineral complexes at the nanoscale as one of the processes creating water-repellent coatings on mineral surfaces. The second objective is to quantify the degree of alteration of coated surfaces with regard to water repellence. We introduce a recently developed trial that combines FTIR spectra with contact-angle data as the link between chemical composition of OM and the physical wetting behavior of soil particles. In addition to characterizing the wetting properties of OM coatings, we discuss the implications of water-repellent surfaces for different physical protection mechanisms of OM. For typical minerals, the OM loading on mineral surfaces is patchy, whereas OM forms nanoscaled micro-aggregates together with metal oxides and hydroxides and with layered clay minerals. Such small aggregates may efficiently stabilize OM against microbial decomposition. However, despite the patchy structure of OM coating, we observed a relation between the chemical composition of OM and wettability. A higher hydrophobicity of the OM appears to stabilize the organic C in soil, either caused by a specific reduced biodegradability of OM or indirectly caused by increased aggregate stability. In partly saturated nonaggregated soil, the specific distribution of the pore water appears to further affect the mineralization of OM as a function of wettability. We conclude that the wettability of OM, quantified by the contact angle, links the chemical structure of OM with a bundle of physical soil properties and that reduced wettability results in the stabilization of OM in soils.

Regulation of the endothelin system by shear stress in human endothelial cells

Abstract: In this study, the effect of shear stress on the expression of genes of the human endothelin-1 system was examined. Primary cultures of human umbilical vein endothelial cells (HUVEC) were exposed to laminar shear stress of 1, 15 or 30 dyn cm-2 (i.e. 0.1, 1.5 or 3 N m-2) (venous and two different arterial levels of shear stress) in a cone-and-plate viscometer. Laminar shear stress transiently upregulates preproendothelin-1 (ppET-1) mRNA, reaching its maximum after 30 min (approx 1.7-fold increase). In contrast, long-term application of shear stress (24 h) causes downregulation of ppET-1 mRNA in a dose-dependent manner. Arterial levels of shear stress result in downregulation of endothelin-converting enzyme-1 isoform ECE-1a (predominating in HUVEC) to 36.2 +/- 8.5 %, and isoform ECE-1b mRNA to 72.3 +/- 1.9 % of static control level. The endothelin-1 (ET-1) release is downregulated by laminar shear stress in a dose-dependent manner. This downregulation of ppET-1 mRNA and ET-1 release is not affected by inhibition of protein kinase C (PKC), or tyrosine kinase. Inhibition of endothelial NO synthase (L-NAME, 500 microm) prevents downregulation of ppET-1 mRNA by shear stress. In contrast, increasing degrees of long-term shear stress upregulate endothelin receptor type B (ETB) mRNA by a NO- and PKC-, but not tyrosine kinase-dependent mechanism. In conclusion, our data suggest the downregulation of human endothelin synthesis, and an upregulation of the ETB receptor by long-term arterial laminar shear stress. These effects might contribute to the vasoprotective and anti-arteriosclerotic potential of arterial laminar shear stress.

VANTED v2: a framework for systems biology applications

Abstract: Background Experimental datasets are becoming larger and increasingly complex, spanning different data domains, thereby expanding the requirements for respective tool support for their analysis. Networks provide a basis for the integration, analysis and visualization of multi-omics experimental datasets.

Student violence against teachers: Teachers' well-being and the belief in a just world.

Abstract: . This paper presents two studies investigating student violence against teachers in Slovakian secondary schools. The studies aimed at gauging the prevalence of student violence (Study 1) and at testing the hypothesis that teacher well-being can be explained by student violence and by teachers' belief in a just world (BJW) (Study 2). Study 1 examined a representative sample of 364 teachers in one of the eight Slovakian provinces, and found that 177 (49%) of them reported at least one experience of violence in the last 30 days. Reports of violence were particularly widespread in vocational schools in the provincial capital. Study 2 investigated a sample of 108 teachers at Slovakian vocational schools, and found that 60 (55%) of them reported at least one experience of violence in the last 15 days. The more violence the teachers reported, the more often they experienced negative affect, the less often they experienced positive affect, and the less satisfied they were with life. Finally, the BJW was ...

Fungal cytochrome P450 sterol 14α-demethylase (CYP51) and azole resistance in plant and human pathogens

Abstract: Azoles have been applied widely to combat pathogenic fungi in medicine and agriculture and, consequently, loss of efficacy has occurred in populations of some species. Often, but not always, resistance was found to result from amino acid substitutions in the molecular target of azoles, 14α-sterol demethylase (CYP51 syn. ERG11). This review summarizes CYP51 function, evolution, and structure. Furthermore, we compare the occurrence and contribution of CYP51 substitutions to azole resistance in clinical and field isolates of important fungal pathogens. Although no crystal structure is available yet for any fungal CYP51, homology modeling using structures from other origins as template allowed deducing models for fungal orthologs. These models served to map amino acid changes known from clinical and field isolates. We conclude with describing the potential consequences of these changes on the topology of the protein to explain CYP51-based azole resistance. Knowledge gained from molecular modeling and resistance research will help to develop novel azole structures.