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1.
Colloids Surf B Biointerfaces ; 183: 110284, 2019 Nov 01.
Article in English | MEDLINE | ID: mdl-31421406

ABSTRACT

Bacterial surface layer proteins (S-layer) possess unique binding properties for metal ions. By combining the binding capability of S-layer proteins with the optical properties of gold nanoparticles (AuNP), namely plasmonic resonance, a colorimetric detection system for metal and metalloid ions in water was developed. Eight S-layer proteins from different bacteria species were used for the functionalization of AuNP. The thus developed biohybrid systems, AuNP functionalized with S-layer proteins, were tested with different metal salt solutions, e.g. Indium(III)-chloride, Yttrium(III)-chloride or Nickel(II)-chloride, to determine their selective and sensitive binding to ionic analytes. All tested S-layer proteins displayed unique binding affinities for the different metal ions. For each S-layer and metal ion combination markedly different reaction patterns and differences in concentration range and absorption spectra were detected by UV/vis spectroscopy. In this way, the selective detection of tested metal ions was achieved by differentiated analysis of a colorimetric screening assay of these biohybrid systems. A highly selective and sensitive detection of yttrium ions down to a concentration of 1.67 × 10-5 mol/l was achieved with S-layer protein SslA functionalized AuNP. The presented biohybrid systems can thus be used as a sensitive and fast sensor system for metal and metalloid ions in aqueous systems.


Subject(s)
Colorimetry/methods , Indium/isolation & purification , Nickel/isolation & purification , Water Pollutants, Chemical/isolation & purification , Yttrium/isolation & purification , Bacillaceae/chemistry , Gold/chemistry , Humans , Membrane Glycoproteins/chemistry , Metal Nanoparticles/chemistry , Protein Binding , Sporosarcina/chemistry , Surface Plasmon Resonance/methods , Water/chemistry
2.
Neuropathol Appl Neurobiol ; 43(4): 299-314, 2017 Jun.
Article in English | MEDLINE | ID: mdl-26918424

ABSTRACT

AIMS: Mesenchymal stem cells (MSC) have recently attracted interest as a potential basis for a cell-based therapy of AD. We investigated the putative immune-modulatory effects in neuroinflammation of systemic transplantation of MSC into APP/PS1 transgenic mice. METHODS: 106 MSC were injected into APP/PS1 mice via the tail vein and histological analysis was performed for microglia and amyloid (pE3-Aß) plaque numbers, glial distribution and pE3-Aß plaque size. In addition, a biochemical analysis by qPCR for pro-inflammatory, chemoattractant and neurotrophic factors was performed. RESULTS: MSC are associated with pE3-Aß plaques. The effects of transplantation on microglia-associated pathology could be observed after 28 days. Animals showed a reduction in microglial numbers in the cortex and in microglia size. Gene expression was reduced for TNF-α, IL-6, MCP-1, and for NGF, in MSC recipients. Also, we investigated for the first time and found no changes in expression of IL-10, CCR5, BDNF, VEGF and IFNγ. PTGER2 expression levels were increased in the hippocampus but were reduced in the cortex of MSC recipients. While there were no transplant-related changes in pE3-Aß plaque numbers, a reduction in the size of pE3-Aß plaques was observed in the hippocampus of transplant recipients. CONCLUSION: This is the first study to show reduction in pE3-Aß plaque size. pE3-Aß plaques have gained attention as potential key participants in AD due to their increased aggregation propensity, the possibility for the initial seeding event, resistance against degradation and neurotoxicity. These findings support the hypothesis that MSC-transplants may affect AD pathology via an immune-modulatory function that includes an effect on microglial cells.


Subject(s)
Alzheimer Disease/pathology , Brain/pathology , Mesenchymal Stem Cell Transplantation/methods , Plaque, Amyloid/pathology , Animals , Mice , Mice, Transgenic
3.
Eur J Neurol ; 22(11): 1488-91, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26333310

ABSTRACT

BACKGROUND AND PURPOSE: Although the genetic contribution to stroke risk is well known, it remains unclear if young-onset stroke has a stronger genetic contribution than old-onset stroke. This study aims to compare the heritability of ischaemic stroke risk between young and old, using common genetic variants from whole-genome array data in population-based samples. METHODS: This analysis included 4050 ischaemic stroke cases and 5765 controls from six study populations of European ancestry; 47% of cases were young-onset stroke (age < 55 years). To quantify the heritability for stroke risk in these unrelated individuals, the pairwise genetic relatedness was estimated between individuals based on their whole-genome array data using a mixed linear model. Heritability was estimated separately for young-onset stroke and old-onset stroke (age ≥ 55 years). RESULTS: Heritabilities for young-onset stroke and old-onset stroke were estimated at 42% (±8%, P < 0.001) and 34% (±10%, P < 0.001), respectively. CONCLUSIONS: Our data suggest that the genetic contribution to the risk of stroke may be higher in young-onset ischaemic stroke, although the difference was not statistically significant.


Subject(s)
Brain Ischemia/genetics , Genetic Predisposition to Disease , Stroke/genetics , Adult , Age of Onset , Aged , Aged, 80 and over , Brain Ischemia/epidemiology , Female , Genotype , Humans , Male , Middle Aged , Risk , Stroke/epidemiology , White People/genetics
4.
J Phys Chem B ; 114(24): 8284-9, 2010 Jun 24.
Article in English | MEDLINE | ID: mdl-20518510

ABSTRACT

Bacterial surface layer protein sheets (S layer) coated with an ultrathin cobalt or silver film were studied by means of laterally resolved near-edge X-ray absorption fine structure spectroscopy performed by photoemission electron microscopy. Comparison with results obtained on pristine S layers allowed us to characterize both chemical interaction and X-ray damage in these protein-metal hybrid systems. In particular, we found that besides direct damage upon exposure to X-ray radiation the biomolecules experience additional contribution of the deposited metals, by low-energy electron generation in the metal particles.


Subject(s)
Cobalt/chemistry , Proteins/chemistry , Silver/chemistry , X-Ray Absorption Spectroscopy , X-Rays
5.
Phys Rev Lett ; 102(9): 098101, 2009 Mar 06.
Article in English | MEDLINE | ID: mdl-19392567

ABSTRACT

The degrees of charge localization in the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of the bacterial surface layer protein of Bacillus sphaericus NCTC 9602 were studied by resonant photoemission. In agreement with a charge transport hopping mechanism that involves torsional motions of the peptide backbone, the lifetime of electrons excited into the LUMO was found to be approximately 100 fs.


Subject(s)
Bacterial Proteins/chemistry , Membrane Glycoproteins/chemistry , Bacillus/chemistry , Bacillus/metabolism , Bacterial Proteins/metabolism , Membrane Glycoproteins/metabolism , Models, Molecular , Spectrometry, X-Ray Emission/methods
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