University of Konstanz

About: University of Konstanz is a education organization based out in Konstanz, Baden-Württemberg, Germany. It is known for research contribution in the topics: Population & Visualization. The organization has 12115 authors who have published 27401 publications receiving 951162 citations. The organization is also known as: University of Constance & Universität Konstanz.

Characterization of SAF-A, a novel nuclear DNA binding protein from HeLa cells with high affinity for nuclear matrix/scaffold attachment DNA elements.

Abstract: We identified four proteins in nuclear extracts from HeLa cells which specifically bind to a scaffold attachment region (SAR) element from the human genome. Of these four proteins, SAF-A (scaffold attachment factor A), shows the highest affinity for several homologous and heterologous SAR elements from vertebrate cells. SAF-A is an abundant nuclear protein and a constituent of the nuclear matrix and scaffold. The homogeneously purified protein is a novel double stranded DNA binding protein with an apparent molecular weight of 120 kDa. SAF-A binds at multiple sites to the human SAR element; competition studies with synthetic polynucleotides indicate that these sites most probably reside in the multitude of A/T-stretches which are distributed throughout this element. In addition we show by electron microscopy that the protein forms large aggregates and mediates the formation of looped DNA structures.

Identification of reggie-1 and reggie-2 as plasmamembrane-associated proteins which cocluster with activated GPI-anchored cell adhesion molecules in non-caveolar micropatches in neurons.

Abstract: Neurons are believed to possess plasmalemmal microdomains and proteins analogous to the caveolae and caveolin of nonneuronal cells. Caveolae are plasmalemmal invaginations where activated glycosyl-phosphatidylinositol (GPI)-anchored proteins preferentially assemble and where transmembrane signaling may occur. Molecular cloning of rat reggie-1 and -2 (80% identical to goldfish reggie proteins) shows that reggie-2 is practically identical to mouse flotillin-1. Flotillin-1 and epidermal surface antigen (ESA) (flotillin-2) are suggested to represent possible membrane proteins in caveolae. Rat reggie-1 is 99% homologous to ESA in overlapping sequences but has a 49-amino-acid N-terminus not present in ESA. Antibodies (ABs) which recognize reggie-1 or -2 reveal that both proteins cluster at the plasmamembrane and occur in micropatches in neurons [dorsal root ganglia (DRGs), retinal ganglion, and PC-12 cells] and in nonneuronal cells. In neurons, reggie micropatches occur along the axon and in lamellipodia and filopodia of growth cones, but they do not occur in caveolae. By quantitative electronmicroscopic analysis we demonstrate the absence of caveolae in (anti-caveolin negative) neurons and show anti-reggie-1 immunogold-labeled clusters at the plasmamembrane of DRGs. When ABs against the GPI-anchored cell adhesion molecules (CAMs) F3 and Thy-1 are applied to live DRGs, the GPI-linked CAMs sequester into micropatches. Double immunofluorescence shows a colocalization of the CAMs with micropatches of anti-reggie antibodies. Thus, reggie-1 and reggie-2 identify sites where activated GPI-linked CAMs preferentially accumulate and which may represent noncaveolar micropatches (domains).

Anaerobic naphthalene degradation by a sulfate-reducing enrichment culture.

Abstract: Anaerobic naphthalene degradation by a sulfate-reducing enrichment culture was studied by substrate utilization tests and identification of metabolites by gas chromatography-mass spectrometry. In substrate utilization tests, the culture was able to oxidize naphthalene, 2-methylnaphthalene, 1- and 2-naphthoic acids, phenylacetic acid, benzoic acid, cyclohexanecarboxylic acid, and cyclohex-1-ene-carboxylic acid with sulfate as the electron acceptor. Neither hydroxylated 1- or 2-naphthoic acid derivatives and 1- or 2-naphthol nor the monoaromatic compounds ortho-phthalic acid, 2-carboxy-1-phenylacetic acid, and salicylic acid were utilized by the culture within 100 days. 2-Naphthoic acid accumulated in all naphthalene-grown cultures. Reduced 2-naphthoic acid derivatives could be identified by comparison of mass spectra and coelution with commercial reference compounds such as 1,2,3,4-tetrahydro-2-naphthoic acid and chemically synthesized decahydro-2-naphthoic acid. 5,6,7,8-Tetrahydro-2-naphthoic acid and octahydro-2-naphthoic acid were tentatively identified by their mass spectra. The metabolites identified suggest a stepwise reduction of the aromatic ring system before ring cleavage. In degradation experiments with [1-13C]naphthalene or deuterated D8-naphthalene, all metabolites mentioned derived from the introduced labeled naphthalene. When a [13C]bicarbonate-buffered growth medium was used in conjunction with unlabeled naphthalene, 13C incorporation into the carboxylic group of 2-naphthoic acid was shown, indicating that activation of naphthalene by carboxylation was the initial degradation step. No ring fission products were identified.