Antimicrobial effects of free nitrous acid on Desulfovibrio vulgaris: Implications for sulfide-induced corrosion of concrete

Hydrogen sulfide produced by sulfate reducing bacteria (SRB) in sewers causes odor problems and asset deterioration due to the sulfide induced concrete corrosion. Free nitrous acid (FNA) was recently demonstrated as a promising antimicrobial agent to alleviate hydrogen sulfide production in sewers. However, knowledge of the antimicrobial mechanisms of FNA is largely unknown. Here we report the multiple-targeted antimicrobial effects of FNA on the SRB Desulfovibrio vulgaris Hildenborough by determining growth, physiological and gene expression responses to FNA exposure. The activities of growth, respiration and ATP generation were inhibited when exposed to FNA. These changes were reflected in transcript levels detected during exposure. Removal of FNA was evident by nitrite reduction that likely involved nitrite reductase and the poorly characterised hybrid cluster protein, and the genes coding for these proteins were highly expressed. During FNA exposure lowered ribosome activity and protein production were detected. Additionally, conditions within the cells were more oxidising and there was evidence of oxidative stress. Based on interpretation of the measured responses we present a model depicting the antimicrobial effects of FNA on D. vulgaris. These findings provide new insight for understanding the responses of D. vulgaris to FNA and will provide foundation for optimal application of this antimicrobial agent for improved control of sewer corrosion and odor management

Esophageal perforation caused by external air-blast injury

<p>Abstract</p> <p>Background</p> <p>Esophageal perforation after external air-blast trauma is rarely presented in the emergency room. The diagnosis is often delayed more than 24 hours.</p> <p>Methods</p> <p>We review the literature and report a case of esophageal perforation caused by external air-blast injury.</p> <p>Results</p> <p>Including the present case, a total of 5 cases of esophageal perforation were caused by external air-blast injury in English literature. Of them, the common presentations were chest pain and dyspnea. The treatment methods varied with each case. One patient died before diagnosis of esophageal perforation and the others survived after proper surgical management.</p> <p>Conclusions</p> <p>Early diagnosis and proper surgical management can reduce the morbidity and mortality of patients who suffered from esophageal perforation caused by external air-blast injury.</p

Cathelicidin preserves intestinal barrier function in polymicrobial sepsis.

ObjectivesThe intestinal epithelium compartmentalizes the sterile bloodstream and the commensal bacteria in the gut. Accumulating evidence suggests that this barrier is impaired in sepsis, aggravating systemic inflammation. Previous studies reported that cathelicidin is differentially expressed in various tissues in sepsis. However, its role in sepsis-induced intestinal barrier dysfunction has not been investigated.DesignTo examine the role of cathelicidin in polymicrobial sepsis, cathelicidin wild-(Cnlp+/+) and knockout (Cnlp-/-) mice underwent cecal-ligation and puncture (CLP) followed by the assessment of septic mortality and morbidity as well as histological, biochemical, immunological, and transcriptomic analyses in the ileal tissues. We also evaluated the prophylactic and therapeutic efficacies of vitamin D3 (an inducer of endogenous cathelicidin) in the CLP-induced murine polymicrobial sepsis model.ResultsThe ileal expression of cathelicidin was increased by three-fold after CLP, peaking at 4 h. Knockout of Cnlp significantly increased 7-day mortality and was associated with a higher murine sepsis score. Alcian-blue staining revealed a reduced number of mucin-positive goblet cells, accompanied by reduced mucin expression. Increased number of apoptotic cells and cleavage of caspase-3 were observed. Cnlp deletion increased intestinal permeability to 4kD fluorescein-labeled dextran and reduced the expression of tight junction proteins claudin-1 and occludin. Notably, circulating bacterial DNA load increased more than two-fold. Transcriptome analysis revealed upregulation of cytokine/inflammatory pathway. Depletion of Cnlp induced more M1 macrophages and neutrophils compared with the wild-type mice after CLP. Mice pre-treated with cholecalciferol (an inactive form of vitamin D3) or treated with 1alpha, 25-dihydroxyvitamin D3 (an active form of VD3) had decreased 7-day mortality and significantly less severe symptoms. Intriguingly, the administration of cholecalciferol after CLP led to worsened 7-day mortality and the associated symptoms.ConclusionsEndogenous cathelicidin promotes intestinal barrier integrity accompanied by modulating the infiltration of neutrophils and macrophages in polymicrobial sepsis. Our data suggested that 1alpha, 25-dihydroxyvitamin D3 but not cholecalciferol is a potential therapeutic agent for treating sepsis

Distinct Cytokine Profiles of Neonatal Natural Killer T Cells after Expansion with Subsets of Dendritic Cells

Natural killer T (NKT) cells are a highly conserved subset of T cells that have been shown to play a critical role in suppressing T helper cell type 1–mediated autoimmune diseases and graft versus host disease in an interleukin (IL)-4–dependent manner. Thus, it is important to understand how the development of IL-4– versus interferon (IFN)-γ–producing NKT cells is regulated. Here, we show that NKT cells from adult blood and those from cord blood undergo massive expansion in cell numbers (500–70,000-fold) during a 4-wk culture with IL-2, IL-7, phytohemagglutinin, anti-CD3, and anti-CD28 mAbs. Unlike adult NKT cells that preferentially produce both IL-4 and IFN-γ, neonatal NKT cells preferentially produce IL-4 after polyclonal activation. Addition of type 2 dendritic cells (DC2) enhances the development of neonatal NKT cells into IL-4+IFN-γ− NKT2 cells, whereas addition of type 1 dendritic cells (DC1) induces polarization towards IL-4−IFN-γ+ NKT1 cells. Adult NKT cells display limited plasticity for polarization induced by DC1 or DC2. Thus, newly generated NKT cells may possess the potent ability to develop into IL-4+IFN-γ− NKT2 cells in response to appropriate stimuli and may thereafter acquire the tendency to produce both IL-4 and IFN-γ

The effects of particle-induced oxidative damage from exposure to airborne fine particulate matter components in the vicinity of landfill sites on Hong Kong

The physical, chemical and bioreactivity characteristics of fine particulate matter (PM2.5) collected near (<1 km) two landfill sites and downwind urban sites were investigated. The PM2.5 concentrations were significantly higher in winter than summer. Diurnal variations of PM2.5 were recorded at both landfill sites. Soot aggregate particles were identified near the landfill sites, which indicated that combustion pollution due to landfill activities was a significant source. High correlation coefficients (r) implied several inorganic elements and water-soluble inorganic ions (vanadium (V), copper (Cu), chloride (Cl−), nitrate (NO3−), sodium (Na) and potassium (K)) were positively associated with wind flow from the landfill sites. Nevertheless, no significant correlations were also identified between these components against DNA damage. Significant associations were observed between DNA damage and some heavy metals such as cadmium (Cd) and lead (Pb), and total Polycyclic Aromatic Hydrocarbons (PAHs) during the summer. The insignificant associations of DNA damage under increased wind frequency from landfills suggested that the PM2.5 loading from sources such as regional sources was possibly an important contributing factor for DNA damage. This outcome warrants the further development of effective and source-specific landfill management regulations for particulate matter production control to the city

Comprehensive methylome map of lineage commitment from haematopoietic progenitors.

Epigenetic modifications must underlie lineage-specific differentiation as terminally differentiated cells express tissue-specific genes, but their DNA sequence is unchanged. Haematopoiesis provides a well-defined model to study epigenetic modifications during cell-fate decisions, as multipotent progenitors (MPPs) differentiate into progressively restricted myeloid or lymphoid progenitors. Although DNA methylation is critical for myeloid versus lymphoid differentiation, as demonstrated by the myeloerythroid bias in Dnmt1 hypomorphs, a comprehensive DNA methylation map of haematopoietic progenitors, or of any multipotent/oligopotent lineage, does not exist. Here we examined 4.6 million CpG sites throughout the genome for MPPs, common lymphoid progenitors (CLPs), common myeloid progenitors (CMPs), granulocyte/macrophage progenitors (GMPs), and thymocyte progenitors (DN1, DN2, DN3). Marked epigenetic plasticity accompanied both lymphoid and myeloid restriction. Myeloid commitment involved less global DNA methylation than lymphoid commitment, supported functionally by myeloid skewing of progenitors following treatment with a DNA methyltransferase inhibitor. Differential DNA methylation correlated with gene expression more strongly at CpG island shores than CpG islands. Many examples of genes and pathways not previously known to be involved in choice between lymphoid/myeloid differentiation have been identified, such as Arl4c and Jdp2. Several transcription factors, including Meis1, were methylated and silenced during differentiation, indicating a role in maintaining an undifferentiated state. Additionally, epigenetic modification of modifiers of the epigenome seems to be important in haematopoietic differentiation. Our results directly demonstrate that modulation of DNA methylation occurs during lineage-specific differentiation and defines a comprehensive map of the methylation and transcriptional changes that accompany myeloid versus lymphoid fate decisions

Carolignans from the Aerial Parts of Euphorbia sikkimensis and Their Anti-HIV Activity

Seven new carolignans, including two pairs of enantiomers (±)-erythro-7′-methylcarolignan E (1a/1b) and (±)-threo-7′-methylcarolignan E (2a/2b), (+)-threo-carolignan E (3a), (+)-erythro-carolignan E (4a), and (−)-erythro-carolignan Z (5), together with four known lignans (3b, 4b, 6, and 7) and six polyphenols (8–13) were isolated from the aerial parts of Euphorbia sikkimensis. The structures of the new compounds were elucidated by spectroscopic analysis, and their absolute configurations were determined by electronic circular dichroism calculations. Seven of the isolates were examined for anti-HIV effects, and compounds 1a and 1b showed moderate anti-HIV activity with EC50 values of 6.3 and 5.3 μM

Critical thickness for the two-dimensional electron gas in LaTiO3/SrTiO3 superlattices

Transport dimensionality of Ti d electrons in (LaTiO3)(1)/(SrTiO3)(N) superlattices has been investigated using density functional theory with local spin-density approximation + U method. Different spatial distribution patterns have been found between Ti t(2g) orbital electrons. The d(xy) orbital electrons are highly localized near interfaces due to the potentials by positively charged LaO layers, while the degenerate d(yz) and d(xz) orbital electrons are more distributed inside SrTiO3 insulators. For N >= 3 unit cells (u.c.), the Ti d(xy) densities of state exhibit the staircaselike increments, which appear at the same energy levels as the d(xy) flat bands along the Gamma-Z direction in band structures. The k(z)-independent discrete energy levels indicate that the electrons in d(xy) flat bands are two-dimensional electron gases (2DEGs) which can transport along interfaces, but they cannot transport perpendicularly to interfaces due to the confinements in the potential wells by LaO layers. Unlike the d(xy) orbital electrons, the d(yz) and d(xz) orbital electrons have three-dimensional (3D) transport characteristics, regardless of SrTiO3 thicknesses. The 2DEG formation by d(xy) orbital electrons, when N >= 3 u.c., indicates the existence of critical SrTiO3 thickness where the electron transport dimensionality starts to change from 3D to 2D in (LaTiO3)(1)/(SrTiO3)(N) superlatticesclose

Unconventional Bose-Einstein condensations from spin-orbit coupling

According to the "no-node" theorem, many-body ground state wavefunctions of conventional Bose-Einstein condensations (BEC) are positive-definite, thus time-reversal symmetry cannot be spontaneously broken. We find that multi-component bosons with spin-orbit coupling provide an unconventional type of BECs beyond this paradigm. We focus on the subtle case of isotropic Rashba spin-orbit coupling and the spin-independent interaction. In the limit of the weak confining potential, the condensate wavefunctions are frustrated at the Hartree-Fock level due to the degeneracy of the Rashba ring. Quantum zero-point energy selects the spin-spiral type condensate through the "order-from-disorder" mechanism. In a strong harmonic confining trap, the condensate spontaneously generates a half-quantum vortex combined with the skyrmion type of spin texture. In both cases, time-reversal symmetry is spontaneously broken. These phenomena can be realized in both cold atom systems with artificial spin-orbit couplings generated from atom-laser interactions and exciton condensates in semi-conductor systems

Determinants of personal exposure to fine particulate matter (PM2.5) adult subjects in Hong Kong

Personal monitoring for fine particulate matter (PM2.5) was conducted for adults (48 subjects, 18-63 years of age) in Hong Kong during the summer and winter of 2014-2015. All filters were analyzed for PM2.5 mass and constituents (including carbonaceous aerosols, water-soluble ions, and elements). We found that season (p = 0.02) and occupation (p &lt; 0.001) were significant factors affecting the strength of the personal-ambient PM2.5 associations. We applied mixed-effects models to investigate the determinants of personal exposure to PM2.5 mass and constituents, along with within- and between-individual variance components. Ambient PM2.5 was the dominant predictor of (R-2 = 0.12-0.59, p &lt; 0.01) and the largest contributor (&gt;37.3%) to personal exposures for PM2.5 mass and most components. For all subjects, a one-unit (2.72 mu g/m(3)) increase in ambient PM2.5 was associated with a 0.75 mu g/m(3) (95% CI: 0.59-0.94 mu g/m(3)) increase in personal PM2.5 exposure. The adjusted mixed-effects models included information extracted from individual&#39;s activity diaries as covariates. The results showed that season, occupation, time indoors at home, in transit, and cleaning were significant determinants for PM2.5 components in personal exposure (R-beta(2) = 0.06-0.63, p &lt; 0.05), contributing to 3.0-70.4% of the variability. For onehour extra time spent at home, in transit; and cleaning an average increase of 1.7-3.6% (ammonium, sulfate, nitrate, sulfur), 2.7-12.3% (elemental carbon, ammonium, titanium, iron), and 8.7-19.4% (ammonium, magnesium ions, vanadium) in components of personal PM2.5 were observed, respectively. In this research, the within-individual variance component dominated the total variability for all investigated exposure data except PM2.5 and EC. Results from this study indicate that performing long-term personal monitoring is needed for examining the associations of mass and constituents of personal PM2.5 with health outcomes in epidemiological studies by describing the impacts of individual-specific data on personal exposures. (C) 2018 Elsevier B.V. All rights reserved