Coping with multiple enemies : pairwise interactions do not predict evolutionary change in complex multitrophic communities

Predicting the ecological and evolutionary trajectories of populations in multispecies communities is one of the fundamental challenges in ecology. Many of these predictions are made by scaling patterns observed from pairwise interactions. Here, we show that the coupling of ecological and evolutionary outcomes is likely to be weaker in increasingly complex communities due to greater chance of life-history trait correlations. Using model microbial communities comprising a focal bacterial species (Bacillus subtilis), a bacterial competitor, protist predator and phage parasite, we found that increasing the number of enemies in a community had an overall negative effect on B. subtilis population growth. However, only the competitor imposed direct selection for B. subtilis trait evolution in pairwise cultures and this effect was weakened in the presence of other antagonists that had a negative effect on the competitor. In contrast, adaptation to parasites was driven indirectly by correlated selection where competitors had a positive and predators a negative effect. For all measured traits, selection in pairwise communities was a poor predictor of B. subtilis evolution in more complex communities. Together, our results suggest that coupling of ecological and evolutionary outcomes is interaction-specific and weakly coupled in more complex communities. We conclude that understanding 2 the ecological and evolutionary mechanisms underpinning trait correlations is crucial to predict species response to global change in complex microbial communitie

Fur : A non-invasive approach to monitor metal exposure in bats

This paper presents a novel assessment of the use of fur as a non-invasive proxy to biomonitor metal contamination in insectivorous bats. Concentrations of metals (cadmium, copper, lead and zinc) were measured using ICP-MS in tissues (kidneys, liver, stomach and stomach content, bones and fur) obtained from 193 Pipistrellus pipistrellus/pygmaeus bats. The bats were collected across a gradient of metal pollution in England and Wales. The utility of small samples of fur as an indicator of metal exposure from the environment was demonstrated with strong relationships obtained between the concentrations of non-essential metals in fur with concentrations in stomach content, kidneys, liver and bones. Stronger relationships were observed for non-essential metals than for essential metals. Fur analyses might therefore be a useful non-invasive proxy for understanding recent, as well as long term and chronic, metal exposure of live animals. The use of fur may provide valuable information on the level of endogenous metal exposure and contamination of bat populations and communities

Affective and perceptual responses during reduced-exertion high-intensity interval training (REHIT)

We have previously demonstrated that reduced-exertion high-intensity interval training (REHIT) is a genuinely time-efficient exercise strategy for improving cardiometabolic health. Here, we examined the affective and perceptual responses to REHIT. Eight young men and women (age 21 ± 1 y, BMI 24.9 ± 2.1 m/kg2, V̇O2max 39 ± 10 ml/kg/min) and 11 men with type 2 diabetes (T2D; age 52 ± 6 y, BMI 29.7 ± 3.1 m/kg2, V̇O2max 29 ± 5 ml/kg/min) took part in three-arm crossover trials with RPE and affective valence measured during, and enjoyment and exercise preferences measured following either: 1) REHIT (2 × 20-s sprints in a 10-min exercise session), 2) HIIT (10 × 1-min efforts) and 3) 30 min MICT. Furthermore, 19 young men and women (age 25 ± 6 y, BMI 24 ± 4 m/kg2, V̇O2max 34 ± 8 ml/kg/min) completed a 6-week REHIT intervention with affective valence during an acute REHIT session measured before and after training. Affect decreases (briefly) during REHIT, but recovers rapidly, and the decline is not significantly different when compared to MICT or HIIT in either healthy participants or T2D patients. Young sedentary participants reported similar levels of enjoyment for REHIT, MICT and HIIT, but 7 out of 8 had a preference for REHIT. Conversely, T2D patients tended to report lower levels of enjoyment with REHIT compared with MICT. The decrease in affective valence observed during an acute REHIT session was significantly attenuated following training. We conclude that affective and perceptual responses to REHIT are no more negative compared to those associated with MICT or HIIT, refuting claims that supramaximal sprint interval training protocols are associated with inherent negative responses

Exposure to flame retardant chemicals on commercial airplanes

Background: Flame retardant chemicals are used in materials on airplanes to slow the propagation of fire. These chemicals migrate from their source products and can be found in the dust of airplanes, creating the potential for exposure. Methods: To characterize exposure to flame retardant chemicals in airplane dust, we collected dust samples from locations inside 19 commercial airplanes parked overnight at airport gates. In addition, hand-wipe samples were also collected from 9 flight attendants and 1 passenger who had just taken a cross-country (USA) flight. The samples were analyzed for a suite of flame retardant chemicals. To identify the possible sources for the brominated flame retardants, we used a portable XRF analyzer to quantify bromine concentrations in materials inside the airplanes. Results: A wide range of flame retardant compounds were detected in 100% of the dust samples collected from airplanes, including BDEs 47, 99, 153, 183 and 209, tris(1,3-dichloro-isopropyl)phosphate (TDCPP), hexabromocyclododecane (HBCD) and bis-(2-ethylhexyl)-tetrabromo-phthalate (TBPH). Airplane dust contained elevated concentrations of BDE 209 (GM: 500 ug/g; range: 2,600 ug/g) relative to other indoor environments, such as residential and commercial buildings, and the hands of participants after a cross-country flight contained elevated BDE 209 concentrations relative to the general population. TDCPP, a known carcinogen that was removed from use in children’s pajamas in the 1970’s although still used today in other consumer products, was detected on 100% of airplanes in concentrations similar to those found in residential and commercial locations. Conclusion: This study adds to the limited body of knowledge regarding exposure to flame retardants on commercial aircraft, an environment long hypothesized to be at risk for maximum exposures due to strict flame retardant standards for aircraft materials. Our findings indicate that flame retardants are widely used in many airplane components and all airplane types, as expected. Most flame retardants, including TDCPP, were detected in 100% of dust samples collected from the airplanes. The concentrations of BDE 209 were elevated by orders of magnitude relative to residential and office environments

Role of liraglutide in Alzheimer's disease pathology

Background The described relationship between Alzheimer's disease (AD) and type 2 diabetes (T2D) and the fact that AD has no succesful treatment has led to the study of antidiabetic drugs that may limit or slow down AD pathology. Main body Although T2D treatment has evident limitations, options are increasing including glucagon-like peptide 1 analogs. Among these, liraglutide (LRGT) is commonly used by T2D patients to improve beta cell function and suppress glucagon to restore normoglycaemia. Interestingly, LRGT also counterbalances altered brain metabolism and has anti-inflammatory properties. Previous studies have reported its capacity to reduce AD pathology, including amyloid production and deposition, tau hyperphosphorylation, or neuronal and synaptic loss in animal models of AD, accompanied by cognitive improvement. Given the beneficial effects of LRGT at central level, studies in patients have been carried out, showing modest beneficial effects. At present, the ELAD trial (Evaluating Liraglutide in Alzheimer's Disease NCT01843075) is an ongoing phase IIb study in patients with mild AD. In this minireview, we resume the outcomes of LRGT treatment in preclinical models of AD as well as the available results in patients up to date. Conclusion The effects of LRGT on animal models show significant benefits in AD pathology and cognitive impairment. While studies in patients are limited, ongoing clinical trials will probably provide more definitive conclusions on the role of LRGT in AD patients

Gac two-component system in Pseudomonas syringae pv. tabaci is required for virulence but not for hypersensitive reaction

Pseudomonas syringae pv. tabaci 6605 causes wildfire disease on host tobacco plants. To investigate the regulatory mechanism of the expression of virulence, Gac two-Component system-defective mutants, Delta gacA and Delta gacS, and a double mutant, Delta gacA Delta gacS, were generated. These mutants produced smaller amounts of N-acyl homoserine lactones required for quorum sensing, had lost swarming motility, and had reduced expression of virulence-related hrp genes and the algT gene required for exopolysaccharide production. The ability of the mutants to cause disease symptoms in their host tobacco plant was remarkably reduced, while they retained the ability to induce hypersensitive reaction (HR) in the nonhost plants. These results indicated that the Gac two-component system of P. syringae pv. tabaci 6605 is indispensable for virulence on the host plant, but not for HR induction in the nonhost plants.</p

Saskatchewan Northern Health Authorities, Saskatchewan Correspondence and reprints: Dr James Irvine, Population Health Unit, Athabasca Health Authority, Keewatin Yatthé Health Region and Mamawetan Churchill River Health Region, Box 6000, LaRonge, Saskatch

A 51-year-old Aboriginal woman from northern Saskatchewan presented to a local family medical clinic in early October 2006 with a three-day history of left knee pain. Her vital signs included a blood pressure of 114/70 mmHg, a heart rate of 100 beats/min and a respiratory rate of 20 breaths/min. Her temperature was not documented. On examination, her knee was warm and painful, and an effusion was noted. Approximately six weeks prior, she had fallen on her right knee while walking. This injury was complicated by hemarthrosis and effusion, requiring needle drainage on two occasions. In addition, she had a history of pain, swelling and erythema involving her shoulder joint. Her past history was significant for alcohol abuse and unstable social and housing conditions. The laboratory results showed the followingwhite blood cell (WBC) count 9.8×10 9 /L (normal 0.2×10 9 /L to 10×10 9 /L); granulocyte count 8.8×10 9 /L (normal 2×10 9 /L to 7.8×10 9 /L); hemoglobin (Hb) level 102 g/L (normal 120 g/L to 180 g/L) and platelet count 68×10 9 /L (normal 150×10 9 /L to 450×10 9 /L). A presumptive diagnosis of inflammatory arthritis was made, and she was given indomethacin 50 mg three times a day for her symptoms. Two days later, the patient became progressively more confused, disoriented and unresponsive to questions. She was brought by ambulance to the local emergency department where her temperature was 38.8°C, pulse 98 beats/min, blood pressure 140/83 mmHg and respiratory rate 32 breaths/min. Her Glasgow coma scale score was 6. She was unresponsive to verbal commands but responsive to painful stimuli. Bruising was noted on both legs, and a large area of erythema was noted around the left knee. Her respiratory examination was unremarkable. Laboratory results showed the following -WBC count 3. 135 U/L) and creatine kinase isoenzyme -MB level 28 U/L (normal 0 U/L to 16 U/L). An evolving neurological condition was thought to be the primary diagnosis. Initial management included intravenous fluid (200 mL/h), cefotaxime 2 g administered intravenously, and blood cultures. She was transferred by air to the Royal University Hospital in Saskatoon, Saskatchewan. During the 1 h flight to Saskatoon, the area of erythema on her left leg tripled in size, and 3 L of intravenous fluids and dopamine were required to stabilize her blood pressure. On arrival, she was noted to be diffusely rigid with no response to painful stimuli. Her temperature was 39°C. She had rigors, peripheral mottling, absence of peripheral pulses, bronchial breath sounds over the right middle lobe, and erythema and target-like lesions over her left knee. Laboratory evaluation on admission showed the following -WBC count 3.

Testing the paradox of enrichment along a land use gradient in a multitrophic aboveground and belowground community

In the light of ongoing land use changes, it is important to understand how multitrophic communities perform at different land use intensities. The paradox of enrichment predicts that fertilization leads to destabilization and extinction of predator-prey systems. We tested this prediction for a land use intensity gradient from natural to highly fertilized agricultural ecosystems. We included multiple aboveground and belowground trophic levels and land use-dependent searching efficiencies of insects. To overcome logistic constraints of field experiments, we used a successfully validated simulation model to investigate plant responses to removal of herbivores and their enemies. Consistent with our predictions, instability measured by herbivore-induced plant mortality increased with increasing land use intensity. Simultaneously, the balance between herbivores and natural enemies turned increasingly towards herbivore dominance and natural enemy failure. Under natural conditions, there were more frequently significant effects of belowground herbivores and their natural enemies on plant performance, whereas there were more aboveground effects in agroecosystems. This result was partly due to the “boom-bust” behavior of the shoot herbivore population. Plant responses to herbivore or natural enemy removal were much more abrupt than the imposed smooth land use intensity gradient. This may be due to the presence of multiple trophic levels aboveground and belowground. Our model suggests that destabilization and extinction are more likely to occur in agroecosystems than in natural communities, but the shape of the relationship is nonlinear under the influence of multiple trophic interactions.

Mapping Fusarium solani and Aphanomyces euteiches Root Rot Resistance and Root Architecture Quantitative Trait Loci in Common Bean

Root rot diseases of bean (Phaseolus vulgaris L.) are a constraint to dry and snap bean production. We developed the RR138 RI mapping population from the cross of OSU5446, a susceptible line that meets current snap bean processing industry standards, and RR6950, a root rot resistant dry bean with small brown seeds. We evaluated the RR138 RI population beginning in the F₆ generation for resistance to Fusarium solani f. sp. phaseoli (Burk.) root rot in Oregon and Aphanomyces euteiches (Drechsler) root rot in Wisconsin. The population was evaluated for a set of root architecture traits at the Oregon location. Fusarium solani root rot resistance was evaluated in three seasons, whereas A. euteiches resistance was evaluated in two seasons. For each disease, RR6950 was resistant and OSU 5446 was susceptible. The recombinant inbred (RI) population was normally distributed for reaction to both diseases. We assembled a high-density linkage map using 1689 single-nucleotide polymorphisms (SNPs) from an Illumina 6000-SNP BARCbean6K_3 Beadchip. The map spanned 1196 cM over 11 linkage groups at a density of one SNP per 1.4 cM. Three quantitative trait loci (QTL) associated with A. euteiches were identified, each accounting for 5 to 15% of the total genetic variation, and two QTL associated with F. solani resistance accounted for 9 and 22% of the total genetic variation. A QTL for taproot diameter (TD) and one QTL for basal root angle were identified. The QTL for resistance to the two diseases mapped to different genome locations indicating a different genetic control