43 research outputs found
Keratinocyte and Fibroblast Wound Healing In Vitro Is Repressed by Non-Optimal Conditions but the Reparative Potential Can Be Improved by Water-Filtered Infrared A
It is a general goal to improve wound healing, especially of chronic wounds. As light therapy has gained increasing attention, the positive influence on healing progression of water-filtered infrared A (wIRA), a special form of thermal radiation, has been investigated and compared to the detrimental effects of UV-B irradiation on wound closure in vitro. Models of keratinocyte and fibroblast scratches help to elucidate effects on epithelial and dermal healing. This study further used the simulation of non-optimal settings such as S. aureus infection, chronic inflammation, and anti-inflammatory conditions to determine how these affect scratch wound progression and whether wIRA treatment can improve healing. Gene expression analysis for cytokines ( IL1A , IL6 , CXCL8 ), growth ( TGFB1 , PDGFC ) and transcription factors ( NFKB1 , TP53 ), heat shock proteins ( HSP90AA1 , HSPA1A , HSPD1 ), keratinocyte desmogleins ( DSG1 , DSG3 ), and fibroblast collagen ( COL1A1 , COL3A1 ) was performed. Keratinocyte and fibroblast wound healing under non-optimal conditions was found to be distinctly reduced in vitro. wIRA treatment could counteract the inflammatory response in infected keratinocytes as well as under chronic inflammatory conditions by decreasing pro-inflammatory cytokine gene expression and improve wound healing. In contrast, in the anti-inflammatory setting, wIRA radiation could re-initiate the acute inflammatory response necessary after injury to stimulate the regenerative processes and advance scratch closure
Biophysical Characterization of Pro-apoptotic BimBH3 Peptides Reveals an Unexpected Capacity for Self-Association
Bcl-2 proteins orchestrate the mitochondrial pathway of apoptosis, pivotal for cell death. Yet, the structural details of the conformational changes of pro- and antiapoptotic proteins and their interactions remain unclear. Pulse dipolar spectroscopy (double electron-electron resonance [DEER], also known as PELDOR) in combination with spin-labeled apoptotic Bcl-2 proteins unveils conformational changes and interactions of each protein player via detection of intra- and inter-protein distances. Here, we present the synthesis and characterization of pro-apoptotic BimBH3 peptides of different lengths carrying cysteines for labeling with nitroxide or gadolinium spin probes. We show by DEER that the length of the peptides modulates their homo-interactions in the absence of other Bcl-2 proteins and solve by X-ray crystallography the structure of a BimBH3 tetramer, revealing the molecular details of the inter-peptide interactions. Finally, we prove that using orthogonal labels and three-channel DEER we can disentangle the Bim-Bim, Bcl-xL-Bcl-xL, and Bim-Bcl-xL interactions in a simplified interactome.This work was funded by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germanyâs Excellence StrategyâEXC-2033âProjektnummer 390677874, the DFG Priority Program SPP1601 âNew Frontiers in Sensitivity in EPR Spectroscopyâ (to E.B.), DFG BO 3000/5-1 (to E.B.), SFB958 â Z04 (to E.B.), DFG grant INST 130/972-1 FUGG (to E.B.). P.E.C. is supported by an Australian NHMRC fellowship (1079700
Hurricanes and Climate: the U.S. CLIVAR Working Group on Hurricanes
While a quantitative climate theory of tropical cyclone formation remains elusive, considerable progress has been made recently in our ability to simulate tropical cyclone climatologies and understand the relationship between climate and tropical cyclone formation. Climate models are now able to simulate a realistic rate of global tropical cyclone formation, although simulation of the Atlantic tropical cyclone climatology remains challenging unless horizontal resolutions finer than 50 km are employed. The idealized experiments of the Hurricane Working Group of U.S. CLIVAR, combined with results from other model simulations, have suggested relationships between tropical cyclone formation rates and climate variables such as mid-tropospheric vertical velocity. Systematic differences are shown between experiments in which only sea surface temperature is increases versus experiments where only atmospheric carbon dioxide is increased, with the carbon dioxide experiments more likely to demonstrate a decrease in numbers. Further experiments are proposed that may improve our understanding of the relationship between climate and tropical cyclone formation, including experiments with two-way interaction between the ocean and the atmosphere and variations in atmospheric aerosols
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Hurricanes and Climate: The U.S. CLIVAR Working Group on Hurricanes
While a quantitative climate theory of tropical cyclone formation remains elusive, considerable progress has been made recently in our ability to simulate tropical cyclone climatologies and to understand the relationship between climate and tropical cyclone formation. Climate models are now able to simulate a realistic rate of global tropical cyclone formation, although simulation of the Atlantic tropical cyclone climatology remains challenging unless horizontal resolutions finer than 50 km are employed. This article summarizes published research from the idealized experiments of the Hurricane Working Group of U.S. Climate and Ocean: Variability, Predictability and Change (CLIVAR). This work, combined with results from other model simulations, has strengthened relationships between tropical cyclone formation rates and climate variables such as midtropospheric vertical velocity, with decreased climatological vertical velocities leading to decreased tropical cyclone formation. Systematic differences are shown between experiments in which only sea surface temperature is increased compared with experiments where only atmospheric carbon dioxide is increased. Experiments where only carbon dioxide is increased are more likely to demonstrate a decrease in tropical cyclone numbers, similar to the decreases simulated by many climate models for a future, warmer climate. Experiments where the two effects are combined also show decreases in numbers, but these tend to be less for models that demonstrate a strong tropical cyclone response to increased sea surface temperatures. Further experiments are proposed that may improve our understanding of the relationship between climate and tropical cyclone formation, including experiments with two-way interaction between the ocean and the atmosphere and variations in atmospheric aerosols
The Imaging X-ray Polarimetry Explorer (IXPE): Technical Overview
The Imaging X-ray Polarimetry Explorer (IXPE) will expand the information space for study of cosmic sources, by adding linear polarization to the properties (time, energy, and position) observed in x-ray astronomy. Selected in 2017 January as a NASA Astrophysics Small Explorer (SMEX) mission, IXPE will be launched into an equatorial orbit in 2021. The IXPE mission will provide scientifically meaningful measurements of the x-ray polarization of a few dozen sources in the 2-8 keV band, including polarization maps of several x-ray-bright extended sources and phase-resolved polarimetry of many bright pulsating x-ray sources
In Vitro Lipophilic Antioxidant Capacity, Antidiabetic and Antibacterial Activity of Citrus Fruits Extracts from Aceh, Indonesia
This study reports in vitro lipophilic antioxidant, inhibition of α-amylase and antibacterial activities of extracts of peel and pulp of citrus samples from Aceh, Indonesia. HPLC (high-performance liquid chromatography), phytochemical, and FTIR (fourier transform infrared) analysis detected carotenoids, flavonoids, phenolic acids and terpenoids, contributing to the biological potencies. Most peel and pulp extracts contained lutein and lower concentrations of zeaxanthin, α-carotene, ÎČ-carotene and ÎČ-cryptoxanthin. The extracts also contained flavanone glycosides (hesperidin, naringin and neohesperidin), flavonol (quercetin) and polymethoxylated flavones (sinensetin, tangeretin). L-TEAC (lipophilic trolox equivalent antioxidant capacity) test determined for peel extracts higher antioxidant capacity compared to pulp extracts. All extracts presented α-amylase inhibitory activity, pulp extracts showing stronger inhibitory activity compared to peel extracts. All extracts inhibited the growth of both gram (+) and gram (â) bacteria, with peel and pulp extracts of makin showing the strongest inhibitory activity. Therefore, local citrus species from Aceh are potential sources of beneficial compounds with possible health preventive effects
ÎŽ<sup>13</sup>C and ÎŽ<sup>37</sup>Cl Isotope Fractionation To Characterize Aerobic vs Anaerobic Degradation of Trichloroethylene
Trichloroethylene
(TCE) is a carcinogenic organic chemical impacting
water resources worldwide. Its breakdown by reductive vs oxidative
degradation involves different types of chemical bonds. Hence, if
distinct isotope effects are reflected in dual element (carbon and
chlorine) isotope values, such trends could help distinguishing both
processes in the environment. This work explored dual element isotope
trends associated with TCE oxidation by two pure bacterial cultures: Pseudomonas putida F1 and Methylosinus
trichosporium OB3b, where the latter expresses either
soluble methane-monooxygenase (sMMO) or particulate methane-monooxygenase
(pMMO). Carbon and chlorine isotope enrichment factors of TCE (Δ<sup>13</sup>C = â11.5, â2.4, and â4.2â°; Δ<sup>37</sup>Cl = 0.3, â1.3, and â2.4â°, respectively)
differed strongly between the strains. The dual element isotope trend
for strain F1 (Δ<sup>13</sup>C/Δ<sup>37</sup>Cl = â38)
reflected, as expected, primary carbon and negligible chlorine isotope
effects, whereas unexpectedly large chlorine isotope effects became
apparent in the trend obtained with strain OB3b (Δ<sup>13</sup>C/Δ<sup>37</sup>Cl = +1.7 for sMMO and pMMO). Therefore, although
dual element isotope analysis partly reflects predicted differences
in oxidative vs reductive (Δ<sup>13</sup>C/Δ<sup>37</sup>Cl = 3.4â5.7) degradation, the unexpected OB3b fractionation
data may challenge field interpretation
gemâDiethyl Pyrroline Nitroxide Spin Labels: Synthesis, EPR Characterization, Rotamer Libraries and Biocompatibility
The availability of bioresistant spin labels is crucial for the optimization of siteâdirected spin labeling protocols for EPR structural studies of biomolecules in a cellular context. As labeling can affect proteinsâ fold and/or function, having the possibility to choose between different spin labels will increase the probability to produce spinâlabeled functional proteins. Here, we report the synthesis and characterization of iodoacetamideâ and maleimideâfunctionalized spin labels based on the gemâdiethyl pyrroline structure. The two nitroxide labels are compared to conventional gemâdimethyl analogs by siteâdirected spin labeling (SDSL) electron paramagnetic resonance (EPR) spectroscopy, using two water soluble proteins: T4 lysozyme and Bid. To foster their use for structural studies, we also present rotamer libraries for these labels, compatible with the MMM software. Finally, we investigate the âtrueâ biocompatibility of the gemâdiethyl probes comparing the resistance towards chemical reduction of the NO group in ascorbate solutions and E. coli cytosol at different spin concentrations