Seasonal changes in eicosanoid metabolism in the brown bear

Polyunsaturated fatty acids (PUFAs) exert several important functions across organ systems. During winter, hibernators divert PUFAs from oxidation, retaining them in their tissues and membranes, to ensure proper body functions at low body temperature. PUFAs are also precursors of eicosanoids with pro- and anti-inflammatory properties. This study investigated seasonal changes in eicosanoid metabolism of free-ranging brown bears (Ursus arctos). By using a lipidomic approach, we assessed (1) levels of specific omega-3 and omega-6 fatty acids involved in the eicosanoid cascade and (2) concentrations of eicosanoids in skeletal muscle and blood plasma of winter hibernating and summer active bears. We observed significant seasonal changes in the specific omega-3 and omega-6 precursors. We also found significant seasonal alterations of eicosanoid levels in both tissues. Concentrations of pro-inflammatory eicosanoids, such as thromboxane B2, 5-hydroxyeicosatetraenoic acid (HETE), and 15-HETE and 18-HETE, were significantly lower in muscle and/or plasma of hibernating bears compared to summer-active animals. Further, plasma and muscle levels of 5,6-epoxyeicosatrienoic acid (EET), as well as muscle concentration of 8,9-EET, tended to be lower in bears during winter hibernation vs. summer. We also found lower plasma levels of anti-inflammatory eicosanoids, such as 15dPGJ₂ and PGE₃, in bears during winter hibernation. Despite of the limited changes in omega-3 and omega-6 precursors, plasma and muscle concentrations of the products of all pathways decreased significantly, or remained unchanged, independent of their pro- or anti-inflammatory properties. These findings suggest that hibernation in bears is associated with a depressed state of the eicosanoid cascade.     

Small queens in the ant Ectatomma tuberculatum: a new case of social parasitism

Social parasites exploit the worker force of colonies of other social insects to rear their own young. Social parasitism occurs in several Hymenoptera and is particularly common in several tribes of the ant subfamilies Myrmicinae and Formicinae. Here, we document the occurrence of miniaturized queens (microgynes) in colonies of Ectatomma tuberculatum, an ant belonging to the subfamily Ectatomminae. Behavioral observations and genetic analyses show that microgynes concentrate their reproductive efforts almost exclusively on the production of sexual offspring (microgynes and males), whereas the regular, large queens (macrogynes) produce workers in addition to sexuals. According to mitochondrial and nuclear markers, gene flow between microgynes and macrogynes is extremely limited. Whereas the co-occurrence of microgynes and macrogynes in the related species Ectatomma ruidum constitutes an intraspecific polymorphism associated with alternative dispersal tactics, microgynes found in colonies of E. tuberculatum appear to be a distinct species and to represent the first case of social parasitism in the poneromorph subfamilies of ants.     

Marine pollution: Let us not forget beach sand

A continuous task of the working group "Environmental Monitoring" is the development of methods and guidelines for a systematic and long-term analytical control of the chemical burden of environmental compartments and biota A new recommendation regarding the substance-related environmental monitoring is published in "Environmental Science and Pollution Research" (Rüdel et al., 2009). The "Chemical and Biological Monitoring Series", published in the same journal, originates from the working group or from its individual members also. Some central points of these articles are picked up and updated in this report. Current topics of major concern are the transformation of pharmaceuticals and its consequences for environmental monitoring and the monitoring of biocides and nanoparticles. Besides other objectives the working group "Soil Chemistry and Soil Ecology" focuses on the development and standardisation of methods for the chemical, physical, and biological characterisation of soil pollution by specific contaminants as well as on the elaboration of methods for the assessment of potential harmful effects on soil, soil ecology, and on other potentially targeted environmental media. Recently the working group has summarized its main outcomes and conclusions in the position paper "Target Orientated Exposition Estimation in Soil Assessment" which is part of this report. Furthermore several other initiatives and activities of the working group are presented.     

A test of the senses: fish select novel habitats by responding to multiple cues

Habitat-specific cues play an important role in orientation for animals that move through a mosaic of habitats. Environmental cues can be imprinted upon during early life stages to guide later return to adult habitats, yet many species must orient toward suitable habitats without previous experience of the habitat. It is hypothesized that multiple sensory cues may enable animals to differentiate between habitats in a sequential order relevant to the spatial scales over which the different types of information are conveyed, but previous research, especially for marine organisms, has mainly focused on the use of single cues in isolation. In this study, we investigated novel habitat selection through the use of three different sensory modalities (hearing, vision, and olfaction). Our model species, the French grunt, Haemulon flavolineatum, is a mangrove/seagrass-associated reef fish species that makes several habitat transitions during early life. Using several in situ and ex situ experiments, we tested the response of fish toward auditory, olfactory, and visual cues from four different habitats (seagrass beds, mangroves, rubble, and coral reef). We identified receptivity to multiple sensory cues during the same life phase, and found that different cues induced different reactions toward the same habitat. For example, early-juvenile fish only responded to sound from coral reefs and to chemical cues from mangroves/seagrass beds, while visual cues of conspecifics overruled olfactory cues from mangrove/seagrass water. Mapping these preferences to the ecology of ontogenetic movements, our results suggest sequential cue use would indeed aid successful orientation to novel key habitats in early life.     

Statistical modeling of crystalline silica exposure by trade in the construction industry using a database compiled from the literature

A quantitative determinants-of-exposure analysis of respirable crystalline silica (RCS) levels in the construction industry was performed using a database compiled from an extensive literature review. Statistical models were developed to predict work-shift exposure levels by trade. Monte Carlo simulation was used to recreate exposures derived from summarized measurements which were combined with single measurements for analysis. Modeling was performed using Tobit models within a multimodel inference framework, with year, sampling duration, type of environment, project purpose, project type, sampling strategy and use of exposure controls as potential predictors. 1346 RCS measurements were included in the analysis, of which 318 were non-detects and 228 were simulated from summary statistics. The model containing all the variables explained 22% of total variability. Apart from trade, sampling duration, year and strategy were the most influential predictors of RCS levels. The use of exposure controls was associated with an average decrease of 19% in exposure levels compared to none, and increased concentrations were found for industrial, demolition and renovation projects. Predicted geometric means for year 1999 were the highest for drilling rig operators (0.238 mg m(-3)) and tunnel construction workers (0.224 mg m(-3)), while the estimated exceedance fraction of the ACGIH TLV by trade ranged from 47% to 91%. The predicted geometric means in this study indicated important overexposure compared to the TLV. However, the low proportion of variability explained by the models suggests that the construction trade is only a moderate predictor of work-shift exposure levels. The impact of the different tasks performed during a work shift should also be assessed to provide better management and control of RCS exposure levels on construction sites.     

Examination of environmental quality of raw and composting de-inking paper sludge

Paper sludges were traditionally landfilled or burned. Over the years, the use of paper sludges on soils has increased, as well as the concerns about their environmental effects. Therefore, the chemical characterization of paper sludges and their young (immature) compost needed to be investigated, and over 150 inorganic and organic chemicals were analyzed in de-inking paper sludge (DPS). In general, nitrogen, phosphorus and potassium contents were low but variable in raw DPS and its young compost. The contents of arsenic, boron, cadmium, cobalt, chromium, manganese, mercury, molybdenum, nickel, lead, selenium, and zinc were also low and showed low variability. However, the copper contents were above the Canadian compost regulation for unrestricted use and required a follow-up. The fatty- and resin acids, and polycyclic aromatic hydrocarbons were the organic chemicals measured at the highest concentrations. For resinic acids, care should be taken to avoid that leachates reach aquatic life. For polycyclic aromatic hydrocarbons, naphthalene should be followed until soil content reaches 0.1 microg g(-1), the maximum allowed for soil use for agricultural purposes according to Canadian Environmental Quality Guidelines. In young compost, the concentration of these chemical families decreased over time and most compounds were below the detection limits after 24 weeks of composting. In raw DPS, among the phenol, halogenated and monoaromatic hydrocarbons, dioxin and furan, and polychlorinated biphenyl families, most compounds were below the detection limits. The raw DPS and its young compost do not represent a major threat for the environment but can require an environmental follow-up.     

Rollover injury: effects of near- and far-seating position, belt use, and number of quarter rolls

PURPOSE: Vehicle and occupant responses in rollovers are complex since many factors influence both. This study analyzes the following factors: 1) belt use, 2) seated position with respect to the lead side in the rollover, 3) another front occupant in the crash, and 4) number of quarter rolls. The aim was to improve our understanding of rollover injury mechanisms. METHOD: Rollover accidents were analyzed using 1992-2004 NASS-CDS data. The sample included adult drivers and right-front passengers. All occupants were evaluated and then a subset of non-ejected occupants was analyzed. Using roll direction and seating position, the sample was divided into near- and far-seated occupants. Injury and fatality risks were determined by seatbelt use, occupancy, rollover direction, and number of quarter rolls. Risk was defined as the number of injured (e.g., MAIS 3+) divided by the number of exposed occupants (MAIS 0-6). Significance in differences was determined. A matched-pair analysis was used to determine the risk of serious injury for near- and far-seated occupants who were either belted or unbelted in the same crash. RESULTS: For all occupants, serious injury risks were highest for far-seated, unbelted occupants at 18.1% +/- 4.8%, followed by near-seated unbelted occupants at 12.0% +/- 3.5%. However, the difference was not statistically significant. Belted near- and far-seated occupants had a similar injury risk of 4.3% +/- 1.2% and 4.0% +/- 1.2%, respectively. For non-ejected occupants, serious injury risk was 9.5% +/- 3.2% for far-seated unbelted occupants and 4.9% +/- 2.1% for near-seated unbelted occupants, not a statistically significant difference. Serious injury risk was similar for belted near- and far-seated non-ejected occupants, at 3.6% +/- 1.1%. Seatbelts were 64.2%-77.9% effective in preventing serious injury for all occupants and 62.1%-26.5% for far- and near-seated, non-ejected occupants, respectively. Based on the matched pairs, seatbelts were less effective for near-seated (5.0%) compared to far-seated (2.8%) occupant MAIS 3+F risks. This was similar for non-ejected occupants. An unbelted near-seated occupant increased the risk for a belted far-seated occupant by 2.2 times, whereas an unbelted far-seated occupant increased the risk for a belted near-seated occupant by 10.2 times. For all occupants, the risk of serious injury increased with the number of quarter rolls, irrespective of seated position. For near-seated occupants, seatbelt effectiveness was higher in < or =1 roll than 1+ roll, at 72.3% compared to 28.3%. For far-seated occupants, seatbelt effectiveness was similar in < or =1 and 1+ roll samples at 78.3% and 76.8%, respectively. Near-seated occupants had the lowest serious injury risk when they were the sole occupant in the vehicle. This was also true for non-ejected occupants. However, far-seated occupants had a lower injury risk when another occupant was involved in the crash. CONCLUSIONS: The effect of carrying another occupant appears to reduce the risk of serious injury to far-seated occupants. However, near-seated occupants are better off being the sole occupant in the vehicle. Seatbelt effectiveness was lowest at 28.3% for non-ejected, near-seated occupants in 1+ rolls. This finding deserves further evaluation in an effort to improve seatbelt effectiveness in rollovers. For belted drivers alone in a rollover, fatality risks are 2.24 times higher for the far- versus near-seated position. Analysis of rollovers by quarter turns indicates that occupants are both far-side and near-side in rollovers. The extent to which this confounds the relationship between roll direction, seating position, and injury risk is unknown.