Intracellular appearance of nitrite and nitrate in nitrogen-starved cells of Ankistrodesmus braunii

Summary The occurrence of heterotrophic nitrification in nitrogen-starved cells of Ankistrodesmus braunii was confirmed. The levels of nitrate and nitrite were measured over a period of four weeks. The validity of quantitative determinations in the presence of highly active nitrate and nitrite reductases is discussed. Whereas free hydroxylamine as an intermediate could not be detected, increased hydroxylamine oxidase activity was found in nitrogen-starved cultures. Nitrite reductase and hydroxylamine oxidase can be assigned to particles by sucrose density gradient centrifugation. The possible involvement of microbodies, which were found to be present in Ankistrodesmus, in metabolic processes during nitrogen starvation is discussed.Abbreviations NR nitrate reductase - NiR nitrite reductase - NNEDA N-(1-naphthyl)ethylenediaminedihydrochloride - DCPIP 2,6-dichlorophenolindophenol - EDTA ethylenediaminetetraacetic acid - TCA trichloroacetic acid - DAB 3,3-diaminobenzidine - AT 3-amino-1H-1,2,4-triazole - AMP 2-amino-2-methyl-1,3-propanediol     

Interference by lipids in the determination of protein using bicinchoninic acid

Bicinchoninic acid forms the basis of an analytical method for the determination of protein. The reagent produces a purple complex with cuprous ion (Cu+) in an alkaline environment and is the basis for the monitoring of cuprous ions produced in the reactions of proteins with alkaline Cu2+. This method of protein determination was reported to have greater tolerance to many commonly encountered interfering compounds, when compared to the Lowry technique. However, we have found the bicinchoninic acid technique to produce erroneously high values for protein when common membrane phospholipids were included in the assay. Phospholipids in the presence of bicinchoninic acid produced an absorbance peak similar to that produced by protein. This absorbance was linear with concentration, however, the slope varied for individual phospholipids. The combined absorption of phospholipid and protein was not strictly additive. The results indicate that the presence of appreciable quantities of lipid in samples can cause significant error in the analysis of protein by the bicinchoninic acid procedure.     

Changes in the miRNA-mRNA Regulatory Network Precede Motor Symptoms in a Mouse Model of Multiple System Atrophy: Clinical Implications

Multiple system atrophy (MSA) is a fatal rapidly progressive α-synucleinopathy, characterized by α-synuclein accumulation in oligodendrocytes. It is accepted that the pathological α-synuclein accumulation in the brain of MSA patients plays a leading role in the disease process, but little is known about the events in the early stages of the disease. In this study we aimed to define potential roles of the miRNA-mRNA regulatory network in the early pre-motor stages of the disease, i.e., downstream of α-synuclein accumulation in oligodendroglia, as assessed in a transgenic mouse model of MSA. We investigated the expression patterns of miRNAs and their mRNA targets in substantia nigra (SN) and striatum, two brain regions that undergo neurodegeneration at a later stage in the MSA model, by microarray and RNA-seq analysis, respectively. Analysis was performed at a time point when α-synuclein accumulation was already present in oligodendrocytes at neuropathological examination, but no neuronal loss nor deficits of motor function had yet occurred. Our data provide a first evidence for the leading role of gene dysregulation associated with deficits in immune and inflammatory responses in the very early, non-symptomatic disease stages of MSA. While dysfunctional homeostasis and oxidative stress were prominent in SN in the early stages of MSA, in striatum differential gene expression in the non-symptomatic phase was linked to oligodendroglial dysfunction, disturbed protein handling, lipid metabolism, transmembrane transport and altered cell death control, respectively. A large number of putative miRNA-mRNAs interaction partners were identified in relation to the control of these processes in the MSA model. Our results support the role of early changes in the miRNA-mRNA regulatory network in the pathogenesis of MSA preceding the clinical onset of the disease. The findings thus contribute to understanding the disease process and are likely to pave the way towards identifying disease biomarkers for early diagnosis of MSA.     

A QTL with major effect on milk yield and composition maps to bovine Chromosome 14

A whole genome scan was undertaken in a granddaughter design comprising 1158 progeny-tested bulls in order to map QTL influencing milk yield and composition. In this paper we report the identification of a locus on the centromeric end of bovine Chromosome (Chr) 14, with major effect on fat and protein percentage as well as milk yield. The genuine nature of this QTL was verified using the grand²-daughter design, that is, by tracing the segregating QTL alleles from heterozygous grandsires to their maternal grandsons and confirming the predicted QTL allele substitution effect. Received: 30 December 1997 / Accepted: 21 February 1998     

NMR assignments of the C-terminal domain of human galectin-8

Galectins recognize β-galectosides to promote a variety of cellular functions. Despite their sequence variations, all galectins share the same carbohydrate recognition domains (CRD) and their modes of ligand recognition at a structural level are essentially identical. Human galectin 8 plays an important role in numerous cancer and immune responses. It consists of two CRDs that are connected via a flexible linker. The substrate affinities and specificities of the N- and C-terminal domains are quite different. In order to investigate the structural basis of their substrate specificities, we complete the NMR ¹H, ¹³C, and ¹⁵N chemical shift assignments of C-terminal domain of human galectin-8 (hG8C).     

Weitere Untersuchungen über die inneren Ursachen der Kälteresistenz

Ohne ZusammenfassungMit 17 Textabbildungen.     

Reproductive performance, population dynamics and anthropometrics of the free-ranging Cayo Santiago rhesus macaques

This report summarizes demographic data collected on the Cayo Santiago colony of rhesus monkeys from 1976-1983 and compares the results with those from 1959-1964 [8,9]. For males and nonpregnant/nonlactating, pregnant, and lactating females mean (+/- 1 SD), body weights, crown-rump lengths, and ponderal indices are tabulated for each age on a large (n = 586) single sampling of this free-ranging population of macaques.     

A multishear microfluidic device for quantitative analysis of calcium dynamics in osteoblasts

Reactive oxygen species (ROS) are an important factor in the development of skin lesions in diabetes. A new antioxidant, hydrogen, can selectively neutralize hydroxyl radicals (OH) and peroxynitrite (ONOO⁻) in cell-free systems, whereas it seldom reacts with other ROS. Fibroblasts are a key component of skin. In the present study, we investigated the protective effects of hydrogen-rich medium on human skin fibroblasts (HSFs) under oxidative stress. Confocal microscopy was used to assay both the intracellular superoxide anion () concentration and the mitochondrial membrane potential (ΔΨ). Cell viability was determined using the Cell Counting Kit-8 (CCK-8). The concentrations of cellular malonaldehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), 8-hydroxy-2′-deoxyguanosine (8-OHdG) and 3-nitrotyrosine (3-NT) were also measured. The results revealed that both mannitol and high glucose could cause oxidative stress in HSFs. Interestingly, the use of a hydrogen-rich medium significantly reduced the level of intracellular , stabilized the ΔΨ and attenuated production of MDA, 8-OHdG and 3-NT which efficiently enhanced the antioxidative defense system and protected the HSFs from subsequent oxidative stress damage. In other words, hydrogen decreased the excessive generation of intracellular and elevated the cellular antioxidative defense. Based on our results, hydrogen may have applications in the treatment of skin diseases caused by diabetes.