Search results for " Density Gradient"

Elevated Regulatory T Cell Levels in Glaucoma Patients in Comparison to Healthy Controls.

2016

Many studies analyzing neurodegenerative diseases demonstrate altered frequencies of regulatory T cells (Tregs). Till date, there is hardly any information concerning Tregs in glaucoma. To gather first results concerning Treg levels in glaucoma patients, we aimed to investigate whether the number of CD4(+)CD25(+)T cells vary in the patients suffering from primary open-angle glaucoma (POAG) and healthy controls.Heparinized blood samples were collected from 16 healthy individuals and 16 POAG patients. The groups were age and gender matched. A density gradient centrifugation over Ficoll-Paque was performed to isolate the peripheral blood mononuclear cells. The resulting cells were stained with…

A 66-kilodalton heat shock protein of Salmonella typhimurium is responsible for binding of the bacterium to intestinal mucus

1992

Salmonella typhimurium infections have increased during the last few years. However, the interplay of virulence factors in S. typhimurium pathogenesis is still poorly understood, particularly with regard to the mechanisms and components of the bacterium which are involved in its interaction with the intestinal mucus. We have observed that S. typhimurium is aggregated by incubation with colonic mucus (guinea pig model). To quantify this phenomenon, an aggregation assay was established. By using this assay, it was found that the aggregation profile of S. typhimurium strains freshly isolated from patients (age 9 and older) with salmonellosis correlated with the severity of the disease. An isol…

Synthesis of a New Disulfide Affinity Adsorbent for Purification of Human Uterine Progesterone Receptor

2005

For purification of the human uterine progesterone receptor, an affinity adsorbent was synthesized in which the specific ligand (16 alpha-ethyl-3-oxo-19nor-androst-4-ene 17 beta-carboxylic acid) was bound to derivatized celulose using a disulfide-group-containing spacer. The purified receptor protein, isolated by reductive cleavage of the disulfide bond, bound the synthetic gestagen R5020 with high affinity (Kd 12.2 nmol/l). The affinity gel was highly efficient. A 24000-fold purification of progesterone receptor with a recovery of 40% could be achieved in a single step within 6 h. By means of dodecyl sulphate/polyacrylamide gel electrophoresis two main polypeptides with molecular weights o…

Sedimentation properties of chitosomal chitin synthetase from the wild-type strain and the 'slime' variant of Neurospora crassa.

1989

Marked differences in the pattern of sedimentation of cellular structures were observed after isopycnic centrifugation of crude cell-free preparations from the Neurospora crassa wall-less 'slime' variant and mycelial wild-type strain. Kinetic studies of particle sedimentation showed that the various types of subcellular components, as revealed by turbidity, UV absorption, polypeptide patterns, and chitin synthetase activity determinations, sediment independently of one another. An important feature was the finding that chitin synthetase from 'slime' peaked at a median specific gravity of 1.1201 +/- 0.0036, whereas that from wild-type strain sedimented at a higher buoyant density (specific g…

Comparative lipidomics and proteomics analysis of platelet lipid rafts using different detergents

2016

Lipid rafts play a pivotal role in physiological functions of platelets. Their isolation using nonionic mild detergents is considered as the gold standard method, but there is no consensual detergent for lipid raft studies. We aimed to investigate which detergent is the most suitable for lipid raft isolation from platelet membrane, based on lipidomics and proteomics analysis. Platelets were obtained from healthy donors. Twelve sucrose fractions were extracted by three different detergents, namely Brij 35, Lubrol WX, and Triton X100, at 0.05% and 1%. After lipidomics analysis and determination of fractions enriched in cholesterol (Ch) and sphingomyelin (SM), proteomics analysis was performed…

Evidence for a selective and electroneutral K+/H+-exchange in Saccharomyces cerevisiae using plasma membrane vesicles

1996

The existence of a K+/H+ transport system in plasma membrane vesicles from Saccharomyces cerevisiae is demonstrated using fluorimetric monitoring of proton fluxes across vesicles (ACMA fluorescence quenching). Plasma membrane vesicles used for this study were obtained by a purification/reconstitution protocol based on differential and discontinuous sucrose gradient centrifugations followed by an octylglucoside dilution/gel filtration procedure. This method produces a high percentage of tightly-sealed inside-out plasma membrane vesicles. In these vesicles, the K+/H+ transport system, which is able to catalyse both K+ influx and efflux, is mainly driven by the K+ transmembrane gradient and ca…

Chlorophyll b is involved in long-wavelength spectral properties of light-harvesting complexes LHC I and LHC II.

2001

AbstractChlorophyll (Chl) molecules attached to plant light-harvesting complexes (LHC) differ in their spectral behavior. While most Chl a and Chl b molecules give rise to absorption bands between 645 nm and 670 nm, some special Chls absorb at wavelengths longer than 700 nm. Among the Chl a/b-antennae of higher plants these are found exclusively in LHC I. In order to assign this special spectral property to one chlorophyll species we reconstituted LHC of both photosystem I (Lhca4) and photosystem II (Lhcb1) with carotenoids and only Chl a or Chl b and analyzed the effect on pigment binding, absorption and fluorescence properties. In both LHCs the Chl-binding sites of the omitted Chl species…

IM30 triggers membrane fusion in cyanobacteria and chloroplasts

2015

The thylakoid membrane of chloroplasts and cyanobacteria is a unique internal membrane system harbouring the complexes of the photosynthetic electron transfer chain. Despite their apparent importance, little is known about the biogenesis and maintenance of thylakoid membranes. Although membrane fusion events are essential for the formation of thylakoid membranes, proteins involved in membrane fusion have yet to be identified in photosynthetic cells or organelles. Here we show that IM30, a conserved chloroplast and cyanobacterial protein of approximately 30 kDa binds as an oligomeric ring in a well-defined geometry specifically to membranes containing anionic lipids. Triggered by Mg2+, membr…

Ultrastructure, fractionation and biochemical analysis of Cryptosporidium parvum sporozoites.

1999

Abstract Sporozoites of the apicomplexan parasite Cryptosporidium parvum were subjected to cell disruption and subcellular fractionation using a sucrose density step gradient. With this procedure, highly enriched preparations of the parasite membrane, the micronemes, dense granules and amylopectin granules were produced. No separate fraction containing rhoptries was obtained, however this organelle was found in defined fractions of the gradient, still associated with the apical tip of the sporozoites. Using negative staining, the internal structure of the micronemes was revealed by transmission electron microscopy. Micronemes and dense granules showed characteristic protein compositions by …

The role of cell interactions in the control of RNA synthesis.

1967