Search results for "Concentration."
showing 10 items of 1849 documents
According to the CPLL proteome sheriffs, not all aperitifs are created equal!
2014
Combinatorial peptide ligand libraries (CPLLs) have been adopted for investigating the proteome of a popular aperitif in Northern Italy, called "Amaro Branzi", stated to be an infusion of a secret herbal mixture, of which some ingredients are declared on the label, namely Angelica officinalis, Gentiana lutea and orange peel, sweetened by a final addition of honey. In order to assess the genuineness of this commercial liqueur, we have prepared extracts of the three vegetable ingredients, assessed their proteomes, and compared them to the one found in the aperitif. The amaro's proteome was identified via prior capture with CPLLs at two different pH values (2.2 and 4.8). Via mass spectrometry …
Identification of enolase as a plasminogen-binding protein in excretory-secretory products ofFasciola hepatica
2004
AbstractWe have followed a combined proteomic approach to identify proteins of Fasciola hepatica that could be involved in host–parasite interactions. Using two-dimensional gel electrophoresis, far Western immunoblot and mass spectrometry analyses, we have identified the enolase enzyme, present in the excretory/secretory materials of F. hepatica, as a human plasminogen-binding protein. This enzyme has an apparent molecular weight of 47 kDa with pI ranging from 6.2 to 7.2. These results suggest that enolase could act as a plasminogen receptor.
Identification of Rothia Bacteria as Gluten-Degrading Natural Colonizers of the Upper Gastro-Intestinal Tract
2011
Background Gluten proteins, prominent constituents of barley, wheat and rye, cause celiac disease in genetically predisposed subjects. Gluten is notoriously difficult to digest by mammalian proteolytic enzymes and the protease-resistant domains contain multiple immunogenic epitopes. The aim of this study was to identify novel sources of gluten-digesting microbial enzymes from the upper gastro-intestinal tract with the potential to neutralize gluten epitopes. Methodology/Principal Findings Oral microorganisms with gluten-degrading capacity were obtained by a selective plating strategy using gluten agar. Microbial speciations were carried out by 16S rDNA gene sequencing. Enzyme activities wer…
Missing value imputation in proximity extension assay-based targeted proteomics data
2020
Targeted proteomics utilizing antibody-based proximity extension assays provides sensitive and highly specific quantifications of plasma protein levels. Multivariate analysis of this data is hampered by frequent missing values (random or left censored), calling for imputation approaches. While appropriate missing-value imputation methods exist, benchmarks of their performance in targeted proteomics data are lacking. Here, we assessed the performance of two methods for imputation of values missing completely at random, the previously top-benchmarked ‘missForest’ and the recently published ‘GSimp’ method. Evaluation was accomplished by comparing imputed with remeasured relative concentrations…
Differential proteomic analysis reveals novel links between primary metabolism and antibiotic production in Amycolatopsis balhimycina.
2010
A differential proteomic analysis, based on 2-DE and MS procedures, was performed on Amycolatopsis balhimycina DSM5908, the actinomycete producing the vancomycin-like antibiotic balhimycin. A comparison of proteomic profiles before and during balhimycin production characterized differentially and constitutively expressed protein isoforms, which were associated to 203 ORFs in the A. balhimycina genome. These data, providing insights on the major metabolic pathways/molecular processes operating in this organism, were used to compile 2-DE reference maps covering 3-10, 4-7 and 4.5-5.5 pH gradients available over the World Wide Web as interactive web pages (http://www.unipa.it/ampuglia/Abal-prot…
Bohr-effect and buffering capacity of hemocyanin from the tarantula E. californicum.
2003
A previous report showed that binding of oxygen to the 24-meric hemocyanin from E. californicum does not correlate linearly with the release of protons as known from hemoglobin. However, this unusual complex phenomenological observation could not be explained at that time. Here, I present a full analysis of the thermodynamic coupling between protons and oxygen for the 24-meric tarantula hemocyanin in Ringer-solution based on the Nested-MWC-model. A strategy is presented which allows to reduce the number of free parameters when fitting the model to the data by including explicitly the equilibrium constants for binding of protons to the different conformations. The results show that the Neste…
Charge-Neutral Constant pH Molecular Dynamics Simulations Using a Parsimonious Proton Buffer
2016
In constant pH molecular dynamics simulations, the protonation states of titratable sites can respond to changes of the pH and of their electrostatic environment. Consequently, the number of protons bound to the biomolecule, and therefore the overall charge of the system, fluctuates during the simulation. To avoid artifacts associated with a non-neutral simulation system, we introduce an approach to maintain neutrality of the simulation box in constant pH molecular dynamics simulations, while maintaining an accurate description of all protonation fluctuations. Specifically, we introduce a proton buffer that, like a buffer in experiment, can exchange protons with the biomolecule enabling its…
Pterostilbene-induced tumor cytotoxicity: a lysosomal membrane permeabilization-dependent mechanism.
2012
The phenolic phytoalexin resveratrol is well known for its health-promoting and anticancer properties. Its potential benefits are, however, limited due to its low bioavailability. Pterostilbene, a natural dimethoxylated analog of resveratrol, presents higher anticancer activity than resveratrol. The mechanisms by which this polyphenol acts against cancer cells are, however, unclear. Here, we show that pterostilbene effectively inhibits cancer cell growth and stimulates apoptosis and autophagosome accumulation in cancer cells of various origins. However, these mechanisms are not determinant in cell demise. Pterostilbene promotes cancer cell death via a mechanism involving lysosomal membrane …
Does market concentration affect prices in the urban water industry?
2015
This paper analyzes the relationship between market concentration in the private segment of the water industry and water prices with a sample of municipalities located in the Southern Spanish region of Andalusia. In doing so, several Heckman sample selection models are estimated with the main finding being that market concentration increases the price of water for residential use charged by private companies. The main policy recommendation is that urban water service privatization must be accompanied by the appropriate regulatory and institutional frameworks to promote competition among businesses and monitor water pricing.
Relationship between airway sensitivity to adenosine 5' monophosphate and the shape of the concentration-response curve to methacholine in subjects w…
2001
Abstract The objective of this study was to determine differences in airway sensitivity to adenosine 5′-monophosphate (AMP) between allergic rhinitis subjects with plateau and those without evidence of plateau on the concentration–response curves to methacholine. A total of 51 adults (38 subjects with allergic rhinitis and 13 healthy controls) were challenged with increasing concentrations of methacholine and AMP. The methacholine challenge was terminated when there was a 40% or more decrease in forced expiratory volume in 1 sec (FEV 1 ), whereas the AMP challenge was stopped when FEV 1 had fallen by more than 20%. A plateau for methacholine was detected in all 13 healthy controls and in 27…