University of Hohenheim

About: University of Hohenheim is a education organization based out in Stuttgart, Germany. It is known for research contribution in the topics: Population & Soil water. The organization has 8585 authors who have published 16406 publications receiving 567377 citations.

Reduction of nitroaromatic compounds by different Pseudomonas species under aerobic conditions

Abstract: Pseudomonas sp. CBS3 converted various nitro-aromatic compounds under aerobic resting-cell conditions to the corresponding amino compounds. Mononitro-compounds were reduced to anilines. 1-Chloro-2,4-dinitrobenzene was reduced via the two possible chloronitroanilines to 4-chloro-1,3-diaminobenzene. In the case of 2,4,6-trinitrotoluene, two monoaminodinitrotoluenes and one diaminomononitrotoluene were obtained. In addition to the reduction, in most cases the amines were partially acetylated. In experiments under an argon atmosphere conversion of the nitro-compounds was as fast as under aerobic conditions. Cells of Pseudomonas sp. CBS3 cultivated on complex medium showed higher nitro-reducing activity than those cultivated on mineral salts medium with 4-chlorobenzoate as substrate, which is normally used as medium for this strain. Several other Pseudomonas species (ATCC 4359, ATCC 23937, ATCC 15005, ATCC 17933) also showed nitro-reducing activities. In crude cell-free extracts of Pseudomonas sp. CBS3 an enzyme catalysing the reduction of nitro-aromatics was detected. The enzyme was inactivated by dialysis and was reactivated by the addition of NADH or NADPH. NADPH was the more efficient co-substrate.

Resveratrol as a Pan-HDAC Inhibitor Alters the Acetylation Status of Jistone Proteins in Human-Derived Hepatoblastoma Cells

Abstract: The polyphenolic alcohol resveratrol has demonstrated promising activities for the prevention and treatment of cancer. Different modes of action have been described for resveratrol including the activation of sirtuins, which represent the class III histone deacetylases (HDACs). However, little is known about the activity of resveratrol on the classical HDACs of class I, II and IV, although these classes are involved in cancer development or progression and inhibitors of HDACs (HDACi) are currently under investigation as promising novel anticancer drugs. We could show by in silico docking studies that resveratrol has the chemical structure to inhibit the activity of different human HDAC enzymes. In vitro analyses of overall HDAC inhibition and a detailed HDAC profiling showed that resveratrol inhibited all eleven human HDACs of class I, II and IV in a dose-dependent manner. Transferring this molecular mechanism into cancer therapy strategies, resveratrol treatment was analyzed on solid tumor cell lines. Despite the fact that hepatocellular carcinoma (HCC) is known to be particularly resistant against conventional chemotherapeutics, treatment of HCC with established HDACi already has shown promising results. Testing of resveratrol on hepatoma cell lines HepG2, Hep3B and HuH7 revealed a dose-dependent antiproliferative effect on all cell lines. Interestingly, only for HepG2 cells a specific inhibition of HDACs and in turn a histone hyperacetylation caused by resveratrol was detected. Additional testing of human blood samples demonstrated a HDACi activity by resveratrol ex vivo. Concluding toxicity studies showed that primary human hepatocytes tolerated resveratrol, whereas in vivo chicken embryotoxicity assays demonstrated severe toxicity at high concentrations. Taken together, this novel pan-HDACi activity opens up a new perspective of resveratrol for cancer therapy alone or in combination with other chemotherapeutics. Moreover, resveratrol may serve as a lead structure for chemical optimization of bioavailability, pharmacology or HDAC inhibition.

A stage-wise approach for the analysis of multi-environment trials.

Abstract: Plant breeders and variety testing agencies routinely test candidate genotypes (crop varieties, lines, test hybrids) in multiple environments. Such multi-environment trials can be efficiently analysed by mixed models. A single-stage analysis models the entire observed data at the level of individual plots. This kind of analysis is usually considered as the gold standard. In practice, however, it is more convenient to use a two-stage approach, in which experiments are first analysed per environment, yielding adjusted means per genotype, which are then summarised across environments in the second stage. Stage-wise approaches suggested so far are approximate in that they cannot fully reproduce a single-stage analysis, except in very simple cases, because the variance-covariance matrix of adjusted means from individual environments needs to be approximated by a diagonal matrix. This paper proposes a fully efficient stage-wise method, which carries forward the full variance-covariance matrix of adjusted means from the individual environments to the analysis across the series of trials. Provided the variance components are known, this method can fully reproduce the results of a single-stage analysis. Computations are made efficient by a diagonalisation of the residual variance-covariance matrix, which necessitates a corresponding linear transformation of both the first-stage estimates (e.g. adjusted means and regression slopes for plot covariates) and the corresponding design matrices for fixed and random effects. We also exemplify the extension of the general approach to a three-stage analysis. The method is illustrated using two datasets, one real and the other simulated. The proposed approach has close connections with meta-analysis, where environments correspond to centres and genotypes to medical treatments. We therefore compare our theoretical results with recently published results from a meta-analysis.

Functional diversity of soil organisms: a review of recent research activities in Germany

Abstract: The aim of this review is to provide an overview of recent investigations on the functional diversity of soil organisms and to elucidate whether a combination of different phenotypic and genotypic assessment methods can give new insights into the relation of structural (phylogenetic) and functional diversity of soil microbial and faunal communities. The knowledge of functional gene sequences for the major microbial transformations enables studies of their presence and diversity in soils. The concomitant evaluation of phylogenetic identification and functional activity of even individual microbial cells in situ is now possible using such as fluorescence in situ hybridization and microautoradiography. Studies about microbial-faunal interactions clarifies the importance of soil organisms for soil processes. Funktionelle Diversitat von Bodenorganismen Dieser Artikel gibt einen uberblick uber neuere Untersuchungen zur funktionellen Diversitat von Mikroorganismen, einigen Vertretern der Bodenmesofauna, sowie der Bodenmakrofauna. Es wird der Frage nachgegangen, inwieweit die Kombination von phanotypischen und genotypischen Untersuchungsmethoden die Erkenntnisse uber die Beziehung von struktureller (phylogenetischer) und funktioneller Diversitat von tierischen und mikrobiellen Lebensgemeinschaften erweitern kann. Die Detailkenntnis der Gensequenzen der zentralen mikrobiellen Transformationsprozesse erlaubt die Untersuchung der Anwesenheit und Diversitat dieses Genpools in Boden. Eine gleichzeitige phylogenetische Identifizierung und Funktionsanalyse auf Einzelzellniveau ist durch den gleichzeitigen Einsatz von Fluoreszenz in situ Hybridisierung mit Gensonden und Mikroautoradiographie moglich. Studien zu Wechselwirkungen von Bodentieren und Bodenmikroorganismen haben die funktionelle Bedeutung von Bodenorganismen geklart.