Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen

Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O₃) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O₃ fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O₃ fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O₃, determined from the mRNA levels of the major allergens. We conclude that O₃ can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase.     

Personal Exposure to Fine Particulate Matter in Elderly Subjects: Relation between Personal,Indoor, and Outdoor Concentrations

ABSTRACT

The time-series correlation between ambient levels, indoor levels, and personal exposure to PM_2.5 was assessed in panels of elderly subjects with cardiovascular disease in Amsterdam, the Netherlands, and Helsinki, Finland. Subjects were followed for 6 months with biweekly clinical visits. Each subject's indoor and personal exposure to PM_2.5 was measured biweekly, during the 24-hr period preceding the clinical visits. Outdoor PM_2.5 concentrations were measured at fixed sites. The absorption coefficients of all PM_2.5 filters were measured as a marker for elemental carbon (EC). Regression analyses were conducted for each subject separately, and the distribution of the individual regression and correlation coefficients was investigated. Personal, indoor, and ambient concentrations were highly correlated within subjects over time. Median Pearson's R between personal and outdoor PM_2.5 was 0.79 in Amsterdam and 0.76 in Helsinki. For absorption, these values were 0.93 and 0.81 for Amsterdam and Helsinki, respectively. The findings of this study provide further support for using fixed-site measurements as a measure of exposure to PM_2.5 in epidemiological time-series studies.     

Wintertime Vertical Variations in Particulate Matter (PM) and Precursor Concentrations in the San Joaquin Valley during the California Regional Coarse PM/Fine PM Air Quality Study

Abstract

Air quality monitoring was conducted at a rural site with a tower in the middle of California’s San Joaquin Valley (SJV) and at elevated sites in the foothills and mountains surrounding the SJV for the California Regional PM₁₀/M_2.5 Air Quality Study. Measurements at the surface and on a tower at 90 m were collected in Angiola, CA, from ecember 2000 through February 2001 and included hourly black carbon (BC), particle counts from optical particle counters, nitric oxide, ozone, temperature, relative humidity, wind speed, and direction. Boundary site measurements were made primarily using 24-hr integrated particulate matter (PM) samples. These measurements were used to understand the vertical variations of PM and PM precursors, the effect of stratification in the winter on concentrations and chemistry aloft and at the surface, and the impact of aloft-versus-surface transport on PM concentrations. Vertical variations of concentrations differed among individual species. The stratification may be important to atmospheric chemistry processes, particularly nighttime nitrate formation aloft, because NO₂ appeared to be oxidized by ozone in the stratified aloft layer. Additionally, increases in accumulation-mode particle concentrations in the aloft layer during a fine PM (PM_2.5) episode corresponded with increases in aloft nitrate, demonstrating the likelihood of an aloft nighttime nitrate formation mechanism. Evidence of local transport at the surface and regional transport aloft was found; transport processes also varied among the species. The distribution of BC appeared to be regional, and BC was often uniformly mixed vertically. Overall, the combination of time-resolved tower and surface measurements provided important insight into PM stratification, formation, and transport.     

An assessment of microbial communities associated with surface mining-disturbed overburden

To assess the microbiological changes that occur during the maturation of overburden that has been disturbed by surface mining of coal, a surface mining-disturbed overburden unit in southeastern Ohio, USA was characterized. Overburden from the same unit that had been disturbed for 37 and 16 years were compared to undisturbed soil from the same region. Overburden and soil samples were collected as shallow subsurface cores from each subregion of the mined area (i.e., land 16 years and 37 years post-mining, and unmined land). Chemical and mineralogical characteristics of overburden samples were determined, as were microbial respiration rates. The composition of microbial communities associated with overburden and soil were determined using culture-independent, nucleic acid-based approaches. Chemical and mineralogical evaluation of overburden suggested that weathering of disturbed overburden gave rise to a setting with lower pH and more oxidized chemical constituents. Overburden-associated microbial biomass and respiration rates increased with time after overburden disturbance. Evaluation of 16S rRNA gene libraries that were produced by “next-generation” sequencing technology revealed that recently disturbed overburden contained an abundance of phylotypes attributable to sulfur-oxidizing Limnobacter spp., but with increasing time post-disturbance, overburden-associated microbial communities developed a structure similar to that of undisturbed soil, but retained characteristics of more recently disturbed overburden. Our results indicate that over time, the biogeochemical weathering of disturbed overburden leads to the development of geochemical conditions and microbial communities that approximate those of undisturbed soil, but that this transition is incomplete after 37 years of overburden maturation.     

Local and systemic induced responses to cabbage root fly larvae (Delia radicum) in Brassica nigra and B. oleracea

Summary. Feeding by belowground herbivores may induce systemic changes in shoot defence levels that affect the performance of above ground herbivores and higher trophic levels. In this paper two wild Brassica species, B. nigra and B. oleracea were experimentally infested with 10 larvae of the cabbage root fly, Delia radicum. Plant dry masses and glucosinolate levels in shoots, main roots, and fine roots were determined at 3, 7, 12 and 14 days after infestation and compared to those of control plants. The systemic response in the leaves differed between plant species. In B. nigra shoot glucosinolate levels in D. radicum infested plants steadily increased with time until they were almost twice those of controls 14 days after infestation. B. oleracea plants infested with D. radicum did not show significant changes in shoot glucosinolate levels within 14 days, which may be due to the unexpected poorer performance of D. radicum on this species. Both plant species showed a local increase in indole glucosinolates in the main roots, which are the preferred feeding site of D. radicum larvae. B. oleracea plants however showed a stronger (1.9 – 4.7 times) increase in indole glucosinolate levels than B. nigra (1.5 – 2.6 times). The increase in indole glucosinolates in B. nigra main roots, was counterbalanced by a significant decrease in aromatic glucosinolate levels. These differences in local responses to D. radicum feeding between the two species may have contributed to the slower growth rates of the larvae on B. oleracea. D. radicum feeding did not result in altered glucosinolate levels in the fine roots in either plant species. The differences in glucosinolate induction patterns between the summer annual B. nigra and the perennial B. oleracea are discussed in the light of their different life histories.     

Biodegradation of phenol and phenol-related compounds by psychrophilic and cold-tolerant alpine yeasts

We characterized 32 cold-adapted, psychrophilic and cold-tolerant, yeast strains isolated from alpine habitats with regard to their taxonomy, growth temperature profile, and ability to degrade phenol and 18 phenol-related mono-aromatic compounds at 10 degrees C. Twenty of the strains were identified by sequencing of the ribosomal ITS region as seven species of the basidiomycota: Cryptococcus terreus (three strains), Cryptococcus terricola (one strain), Rhodosporidium lusitaniae (two strains), Rhodotorula creatinivora (10 strains), Rhodotorula ingeniosa (one strain), Mastigobasidium intermedium (one strain), and Sporobolomyces roseus (two strains). Twelve strains sharing closely related ITS sequences could not be identified to the species level; according to their ITS sequence they are included in the Microbotryomycetidae. These 12 strains were psychrophilic (no growth at temperatures above 20 degrees C); one-third of these strains did not grow above 15 degrees C. None of the 32 strains utilized any of the highly volatile mono-aromatic compounds (benzene, toluene, ethylbenzene, nitrobenzene, o-xylene, m-xylene, and p-xylene) as the sole carbon source. Non/low volatile aromatic compounds were degraded in the following order: phenol>hydroquinone>resorcinol>benzoate>catechol>salicylate>p-cresol>m-cresol. o-Cresol, guaiacol, p-nitrophenol, or p-nitrotoluene were not utilized for growth. R. creatinivora strains degraded up to seven compounds, whereas C. terricola and S. roseus strains degraded only two compounds. The toxicity of the compounds was determined via growth inhibition in the presence of toxicants and nutrients at 10 degrees C. R. creatinivora strains were characterized by higher IC50 values than other species, S. roseus was the most sensitive species. The most toxic compounds were the xylene isomers, ethylbenzene, p-nitrophenol, and m-cresol. There was a relation between the chemical structure of the compounds and their toxicity, whereas a relation between the toxicity of the compounds and the ability of the yeasts strains to utilize these compounds for growth was only detected in some cases.     

Road traffic injury in sub-Saharan African countries: A systematic review and summary of observational studies

Objective: The aim of this study is to evaluate, through a systematic review of hospital-based studies, the proportion of road traffic injuries and fatalities in sub-Saharan Africa (SSA).

Methods: In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology guidelines, we searched the following electronic databases: PubMed, Embase, Africa-Wide Information, Global Health, and Web of Science. Articles were eligible if they measured proportion of road traffic injuries (RTIs) in SSA by using hospital-based studies. In addition, a reference and citation analysis was conducted as well as a data quality assessment.

Results: Up to 2015, there were a total of 83 hospital-based epidemiologic studies, including 310,660 trauma patients and 99,751 RTI cases, in 13 SSA countries. The median proportion of RTIs among trauma patients was 32% (4 to 91%), of which the median proportion of death for the included articles was 5% (0.3 to 41%).

Conclusion: The number of studies evaluating RTI proportions and fatalities in SSA countries is increasing but without the exponential rise expected from World Health Organization calls for research during the Decade of Action for Road Traffic Injuries. Further research infrastructure including standardization of taxonomy, definitions, and data reporting measures, as well as funding, would allow for improved cross-country comparisons.