Structure-Dependent Strain Effects.
Ontology highlight
ABSTRACT:
SUBMITTER: Dietze EM
PROVIDER: S-EPMC7702043 | biostudies-literature | 2020 Nov
REPOSITORIES: biostudies-literature
Publications
Structure-Dependent Strain Effects.
Dietze Elisabeth M EM Grönbeck Henrik H
Chemphyschem : a European journal of chemical physics and physical chemistry 20201007 21
Density functional theory calculations of atomic and molecular adsorption on (111) and (100) metal surfaces reveal marked surface and structure dependent effects of strain. Adsorption in three-fold hollow sites is found to be destabilized by compressive strain whereas the reversed trend is commonly valid for adsorption in four-fold sites. The effects, which are qualitatively explained using a simple two-orbital model, provide insights on how to modify chemical properties by strain design. ...[more]
Similar Datasets
Project description:The Mn K edge X-ray absorption near edge structure (XANES) of Pr0.67Sr0.33MnO3 films with different thicknesses on (001) LaAlO3 substrate was measured, and the effects of strain relaxation on film properties were investigated. The films showed in-plane compressive and out-of-plane tensile strains. Strain relaxation occurred with increasing film thickness, affecting both lattice constant and MnO6 octahedral rotation. In polarization dependent XANES measurements using in-plane (parallel) and out-of-plane (perpendicular) geometries, the different values of absorption resonance energy Er confirmed the film anisotropy. The values of Er along these two directions shifted towards each other with increasing film thickness. Correlating with X-ray diffraction (XRD) results it is suggested that the strain relaxation decreased the local anisotropy and corresponding probability of electronic charge transfer between Mn 3d and O 2p orbitals along the in-plane and out-of-plane directions. The XANES results were used to explain the film-thickness dependent magnetic and transport properties.
| S-EPMC4730223 | biostudies-literature
Project description:Prior studies showed nanoparticle clearance was different in C57BL/6 versus BALB/c mice, strains prone to Th1 and Th2 immune responses, respectively. Objective: Assess nanoceria (cerium oxide, CeO2 nanoparticle) uptake time course and organ distribution, cellular and oxidative stress, and bioprocessing as a function of mouse strain. Methods: C57BL/6 and BALB/c female mice were i.p. injected with 10 mg/kg nanoceria or vehicle and terminated 0.5 to 24 h later. Organs were collected for cerium analysis; light and electron microscopy with elemental mapping; and protein carbonyl, IL-1β, and caspase-1 determination. Results: Peripheral organ cerium significantly increased, generally more in C57BL/6 mice. Caspase-1 was significantly elevated in the liver at 6 h, to a greater extent in BALB/c mice, suggesting inflammasome pathway activation. Light microscopy revealed greater liver vacuolation in C57BL/6 mice and a nanoceria-induced decrease in BALB/c but not C57BL/6 mice vacuolation. Nanoceria increased spleen lymphoid white pulp cell density in BALB/c but not C57BL/6 mice. Electron microscopy showed intracellular nanoceria particles bioprocessed to form crystalline cerium phosphate nanoneedles. Ferritin accumulation was greatly increased proximal to the nanoceria, forming core-shell-like structures in C57BL/6 but even distribution in BALB/c mice. Conclusions: BALB/c mice were more responsive to nanoceria-induced effects, e.g. liver caspase-1 activation, reduced liver vacuolation, and increased spleen cell density. Nanoceria uptake, initiation of bioprocessing, and crystalline cerium phosphate nanoneedle formation were rapid. Ferritin greatly increased with a macrophage phenotype-dependent distribution. Further study will be needed to understand the mechanisms underlying the observed differences.
| S-EPMC8496957 | biostudies-literature
Project description:EXPERIMENT: Microarray expression profiles derived from the cranial neural folds (headfold) of neurulation-stage mouse embryos 3.0h after maternal alcohol exposure on 8 d.p.c. ANIMAL MODEL: Pregnancies from 2 substrains of C57BL/6 mice that differ in relative risk of Fetal Alcohol Syndrome (FAS): C57BL/6J (B6J) high-risk condition, and C57BL/6NCrl (B6N) low-risk condition. EXPOSURE: Dams dosed with ethanol (EtOH) by intraperitoneal injection at 2.9 g EtOH per kg body weight. Controls received vehicle (saline) alone. A third group of dams received EtOH + 4.0 mg/kg PK11195, a specific high-affinity ligand to the 18 KDa mitochondrial peripheral benzodiazepine receptor site. INTERVAL: High blood alcohol content must be sustained in dams for several hours to invoke FAS and is traditionally accomplished by a double injection of EtOH 4.0h apart. Since these embryos were harvested for genetic analysis 1h before dams would have gotten the second alcohol injection, the interval represents a snapshot of the critical response, prior to the second maternal injection that invokes greater risk. Counter-exposure to PK11195 significantly lowers the adverse response of B6J embryos to EtOH. PLATFORM: Two independent assays run. The first dataset (PE), run April 2002 – January 2003, used samples pooled from 2 litters (PE) and the platform was a two-channel MPS621 array (http://www.lifesciences.perkinelmer.com/). This platform has 4800 sequence-verified gene elements derived from over 50 different human cDNA libraries reflecting a variety of well-annotated cellular processes and disease pathways. The second dataset (AF), run between May 2005 – November 2005, used samples pooled from 1 litter and the platform was Affymetrix GeneChip® Mouse Genome 430A 2.0 Array (http://www.affymetrix.com/). The MG430A 2.0 platform has 45,102 oligonucleotide probe cells representing approximately 14,000 well-characterized genes in the draft mouse genome assembly. The corresponding GEO samples are GSM12218 - GSM12227 for the two-channel PE arrays, and GSM136067 - GSM136078 for the one-channel AF arrays. Keywords = fetal alcohol syndrome Keywords = alcohol-related birth defects Keywords = EtOH Keywords = PK11195 Keywords = embryo Keywords = strain differences Keywords: Ordered
2004-03-11 | GSE1074 | GEO
Project description:EXPERIMENT: Microarray expression profiles derived from the cranial neural folds (headfold) of neurulation-stage mouse embryos 3.0h after maternal alcohol exposure on 8 d.p.c. ANIMAL MODEL: Pregnancies from 2 substrains of C57BL/6 mice that differ in relative risk of Fetal Alcohol Syndrome (FAS): C57BL/6J (B6J) high-risk condition, and C57BL/6NCrl (B6N) low-risk condition. EXPOSURE: Dams dosed with ethanol (EtOH) by intraperitoneal injection at 2.9 g EtOH per kg body weight. Controls received vehicle (saline) alone. A third group of dams received EtOH + 4.0 mg/kg PK11195, a specific high-affinity ligand to the 18 KDa mitochondrial peripheral benzodiazepine receptor site. INTERVAL: High blood alcohol content must be sustained in dams for several hours to invoke FAS and is traditionally accomplished by a double injection of EtOH 4.0h apart. Since these embryos were harvested for genetic analysis 1h before dams would have gotten the second alcohol injection, the interval represents a snapshot of the critical response, prior to the second maternal injection that invokes greater risk. Counter-exposure to PK11195 significantly lowers the adverse response of B6J embryos to EtOH. PLATFORM: Two independent assays run. The first dataset (PE), run April 2002 â January 2003, used samples pooled from 2 litters (PE) and the platform was a two-channel MPS621 array (http://www.lifesciences.perkinelmer.com/). This platform has 4800 sequence-verified gene elements derived from over 50 different human cDNA libraries reflecting a variety of well-annotated cellular processes and disease pathways. The second dataset (AF), run between May 2005 â November 2005, used samples pooled from 1 litter and the platform was Affymetrix GeneChip® Mouse Genome 430A 2.0 Array (http://www.affymetrix.com/). The MG430A 2.0 platform has 45,102 oligonucleotide probe cells representing approximately 14,000 well-characterized genes in the draft mouse genome assembly. The corresponding GEO samples are GSM12218 - GSM12227 for the two-channel PE arrays, and GSM136067 - GSM136078 for the one-channel AF arrays. Keywords = fetal alcohol syndrome Keywords = alcohol-related birth defects Keywords = EtOH Keywords = PK11195 Keywords = embryo Keywords = strain differences Keywords: Ordered Assay of early mouse embryos during pathogenesis of Fetal Alcohol Syndrome (FAS). Replicate RNA samples were arrayed by one-channel oligonucleotide (Affymetrix) or two-channel cDNA (Perkin-Elmer) platforms.
2010-06-09 | E-GEOD-1074 | biostudies-arrayexpress
Project description:BackgroundPepino mosaic virus (PepMV) is an emerging plant pathogen that infects tomatoes worldwide. Understanding the factors that influence its evolutionary success is essential for developing new control strategies that may be more robust against the evolution of new viral strains. One of these evolutionary factors is the distribution of mutational fitness effect (DMFE), that is, the fraction of mutations that are lethal, deleterious, neutral, and beneficial on a given viral strain and host species. The goal of this study was to characterize the DMFE of introduced nonsynonymous mutations on a mild isolate of PepMV from the Chilean 2 strain (PepMV-P22). Additionally, we also explored whether the fitness effect of a given mutation depends on the gene where it appears or on epistatic interactions with the genetic background. To address this latter possibility, a subset of mutations were also introduced in a mild isolate of the European strain (PepMV-P11) and the fitness of the resulting clones measured.ResultsA collection of 25 PepMV clones each containing a single nucleotide nonsynonymous substitution was created by site-directed mutagenesis and the fitness of each mutant was determined. PepMV-P22 genome showed a high degree of robustness against point mutations, with 80% of mutations being either neutral or even beneficial and only 20% being deleterious or lethal. We found that the effect of mutations strongly depended on the gene in which they were introduced. Mutations with the largest average beneficial effects were those affecting the RdRp gene, in contrast to mutations affecting TGB1 and CP genes, for which the average effects were deleterious. Moreover, significant epistatic interactions were observed between nonsynonymous mutations and the genetic background, meaning that the effect of a given nucleotide substitution on a particular genomic context cannot be predicted by knowing its effect in a different one.ConclusionsOur results indicated that PepMV genome has a surprisingly high robustness against mutations. We also found that fitness consequences of a given mutation differ between the two strains analyzed. This discovery suggests that the strength of selection, and thus the rates of evolution, vary among PepMV strains.
| S-EPMC5339997 | biostudies-literature
Project description:RNase E is an essential, multifunctional ribonuclease encoded in E. coli by the rne gene. Structural analysis indicates that the ribonucleolytic activity of this enzyme is conferred by rne-encoded polypeptide chains that (1) dimerize to form a catalytic site at the protein-protein interface, and (2) multimerize further to generate a tetrameric quaternary structure consisting of two dimerized Rne-peptide chains. We identify here a mutation in the Rne protein's catalytic region (E429G), as well as a bacterial cell wall peptidoglycan hydrolase (Amidase C [AmiC]), that selectively affect the specific activity of the RNase E enzyme on long RNA substrates, but not on short synthetic oligonucleotides, by enhancing enzyme multimerization. Unlike the increase in specific activity that accompanies concentration-induced multimerization, enhanced multimerization associated with either the E429G mutation or interaction of the Rne protein with AmiC is independent of the substrate's 5' terminus phosphorylation state. Our findings reveal a previously unsuspected substrate length-dependent regulatory role for RNase E quaternary structure and identify cis-acting and trans-acting factors that mediate such regulation.
| S-EPMC7849360 | biostudies-literature
Project description:Multiple animal models have been developed to recapitulate phenotypes of the human disease, schizophrenia. A model that simulates many of the cognitive and sensory deficits of the disorder is the use of random variable prenatal stress (PS) in the rat. These deficits suggest a molecular origin in the hippocampus, a brain region that plays a role in the regulation of stress. To study both hippocampal gene expression changes in offspring of prenatally stressed dams and to address genetic variability, we used a random array of prenatal stressors in three different rat strains with diverse responses to stress: Fischer, Sprague-Dawley, and Lewis rats. Candidate genes involved in stress, schizophrenia, cognition, neurotrophic effects, and immunity were selected for assessment by real-time quantitative PCR under resting conditions and following a brief exposure to restraint stress. PS resulted in significant differences in gene expression in the offspring that were strain dependent. mRNA expression for the N-methyl-D-aspartate receptor subtype 2B (Grin2b) was increased, and tumor necrosis factor-alpha (Tnf?) transcript was decreased in PS Sprague-Dawley and Lewis rats, but not in the Fischer rats. Expression of brain-derived neurotrophic factor (Bdnf) mRNA in the hippocampus was increased after an acute stress in all controls of each strain, yet a decrease was seen after acute stress in the PS Sprague-Dawley and Lewis rats. Expression of the glucocorticoid receptor (Nr3c1) was decreased in the Fischer strain when compared to Lewis or Sprague-Dawley rats, though the Fischer rats had markedly higher ?7 nicotinic receptor (Chrna7) expression. The expression differences seen in these animals may be important elements of the phenotypic differences seen due to PS and genetic background.
| S-EPMC3118943 | biostudies-literature
Project description:Secondary bacterial coinfections following influenza virus pose a serious threat to human health. Therefore, it is of significant clinical relevance to understand the immunological causes of this increased susceptibility. Influenza-induced alterations in alveolar macrophages (AMs) have been shown to be a major underlying cause of the increased susceptibility to bacterial superinfection. However, the mechanisms responsible for this remain under debate, specifically in terms of whether AMs are depleted in response to influenza infection or are maintained postinfection, but with disrupted phagocytic activity. The data presented in this article resolves this issue by showing that either mechanism can differentially occur in individual mouse strains. BALB/c mice exhibited a dramatic IFN-?-dependent reduction in levels of AMs following infection with influenza A, whereas AM levels in C57BL/6 mice were maintained throughout the course of influenza infection, although the cells displayed an altered phenotype, namely an upregulation in CD11b expression. These strain differences were observed regardless of whether infection was performed with low or high doses of influenza virus. Furthermore, infection with either the H1N1 A/California/04/2009 (CA04) or H1N1 A/PR8/1934 (PR8) virus strain yielded similar results. Regardless of AM viability, both BALB/c and C57BL/6 mice showed a high level of susceptibility to postinfluenza bacterial infection. These findings resolve the apparent inconsistencies in the literature, identify mouse strain-dependent differences in the AM response to influenza infection, and ultimately may facilitate translation of the mouse model to clinical application.
| S-EPMC6008236 | biostudies-literature
Project description:BACKGROUND: Molecular genotyping methods have shown infection with more than one Mycobacterium tuberculosis strain genotype in a single sputum culture, indicating mixed infection. AIM: This study aimed to develop a PCR-based genotyping tool to determine the population structure of M. tuberculosis strain genotypes in primary Mycobacterial Growth Indicator Tubes (MGIT) and Löwenstein-Jensen (LJ) cultures to identify mixed infections and to establish whether the growth media influenced the recovery of certain strain genotypes. METHOD: A convenience sample of 206 paired MGIT and LJ M. tuberculosis cultures from pulmonary tuberculosis patients resident in Khayelitsha, South Africa were genotyped using an in-house PCR-based method to detect defined M. tuberculosis strain genotypes. RESULTS: The sensitivity and specificity of the PCR-based method for detecting Beijing, Haarlem, S-family, and LAM genotypes was 100%, and 75% and 50% for detecting the Low Copy Clade, respectively. Thirty-one (15%) of the 206 cases showed the presence of more than one M. tuberculosis strain genotype. Strains of the Beijing and Haarlem genotypes were significantly more associated with a mixed infection (on both media) when compared to infections with a single strain (Beijing MGIT p = 0.02; LJ, p<0.01) and (Haarlem: MGIT p<0.01; LJ, p = 0.01). Strains with the Beijing genotype were less likely to be with "other genotype" strains (p<0.01) while LAM, Haarlem, S-family and LCC occurred independently with the Beijing genotype. CONCLUSION: The PCR-based method was able to identify mixed infection in at least 15% of the cases. LJ media was more sensitive in detecting mixed infections than MGIT media, implying that the growth characteristics of M. tuberculosis on different media may influence our ability to detect mixed infections. The Beijing and Haarlem genotypes were more likely to occur in a mixed infection than any of the other genotypes tested suggesting pathogen-pathogen compatibility.
| S-EPMC3728311 | biostudies-other
Project description:Surface-attached microbial communities consist of different cell types that, at least to some degree, organize themselves non-randomly across space (referred to as spatial self-organization). While spatial self-organization can have important effects on the functioning, ecology and evolution of communities, the underlying determinants of spatial self-organization remain unclear. Here, we hypothesize that the presence of physical objects across a surface can have important effects on spatial self-organization. Using pairs of isogenic strains of Pseudomonas stutzeri, we performed range expansion experiments in the absence or presence of physical objects and quantified the effects on spatial self-organization. We demonstrate that physical objects create local deformities along the expansion frontier, and these deformities increase in magnitude during range expansion. The deformities affect the densities of interspecific boundaries and diversity along the expansion frontier, and thus affect spatial self-organization, but the effects are interaction-dependent. For competitive interactions that promote sectorized patterns of spatial self-organization, physical objects increase the density of interspecific boundaries and diversity. By contrast, for cross-feeding interactions that promote dendritic patterns, they decrease the density of interspecific boundaries and diversity. These qualitatively different outcomes are probably caused by fundamental differences in the orientations of the interspecific boundaries. Thus, in order to predict the effects of physical objects on spatial self-organization, information is needed regarding the interactions present within a community and the general geometric shapes of spatial self-organization that emerge from those interactions. This article is part of the theme issue 'Conceptual challenges in microbial community ecology'.
| S-EPMC7133532 | biostudies-literature