The fate of steroid estrogens: Partitioning during wastewater treatment and onto river sediments

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 Springer Science+Business Media B.V.The partitioning of steroid estrogens in wastewater treatment and receiving waters is likely to influence their discharge to, and persistence in, the environment. This study investigated the partitioning behaviour of steroid estrogens in both laboratory and field studies. Partitioning onto activated sludge from laboratory-scale Husmann units was rapid with equilibrium achieved after 1 h. Sorption isotherms and Kd values decreased in the order 17α-ethinyl estradiol > 17α-estradiol > estrone > estriol without a sorption limit being achieved (1/n >1). Samples from a wastewater treatment works indicated no accumulation of steroid estrogens in solids from primary or secondary biological treatment, however, a range of steroid estrogens were identified in sediment samples from the River Thames. This would indicate that partitioning in the environment may play a role in the long-term fate of estrogens, with an indication that they will be recalcitrant in anaerobic conditions.EPSR

Enhanced hyporheic exchange flow around woody debris does not increase nitrate reduction in a sandy streambed

Anthropogenic nitrogen pollution is a critical problem in freshwaters. Although riverbeds are known to attenuate nitrate, it is not known if large woody debris (LWD) can increase this ecosystem service through enhanced hyporheic exchange and streambed residence time. Over a year, we monitored the surface water and pore water chemistry at 200 points along a ~50m reach of a lowland sandy stream with three natural LWD structures. We directly injected 15N-nitrate at 108 locations within the top 1.5m of the streambed to quantify in situ denitrification, anammox and dissimilatory nitrate reduction to ammonia, which, on average, contributed 85%, 10% and 5% of total nitrate reduction, respectively. Total nitrate reducing activity ranged from 0-16µM h-1 and was highest in the top 30cm of the stream bed. Depth, ambient nitrate and water residence time explained 44% of the observed variation in nitrate reduction; fastest rates were associated with slow flow and shallow depths. In autumn, when the river was in spate, nitrate reduction (in situ and laboratory measures) was enhanced around the LWD compared with non-woody areas, but this was not seen in the spring and summer. Overall, there was no significant effect of LWD on nitrate reduction rates in surrounding streambed sediments, but higher pore water nitrate concentrations and shorter residence times, close to LWD, indicated enhanced delivery of surface water into the streambed under high flow. When hyporheic exchange is too strong, overall nitrate reduction is inhibited due to short flow-paths and associated high oxygen concentrations

Nitrate Reduction Functional Genes and Nitrate Reduction Potentials Persist in Deeper Estuarine Sediments. Why?

Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are processes occurring simultaneously under oxygen-limited or anaerobic conditions, where both compete for nitrate and organic carbon. Despite their ecological importance, there has been little investigation of how denitrification and DNRA potentials and related functional genes vary vertically with sediment depth. Nitrate reduction potentials measured in sediment depth profiles along the Colne estuary were in the upper range of nitrate reduction rates reported from other sediments and showed the existence of strong decreasing trends both with increasing depth and along the estuary. Denitrification potential decreased along the estuary, decreasing more rapidly with depth towards the estuary mouth. In contrast, DNRA potential increased along the estuary. Significant decreases in copy numbers of 16S rRNA and nitrate reducing genes were observed along the estuary and from surface to deeper sediments. Both metabolic potentials and functional genes persisted at sediment depths where porewater nitrate was absent. Transport of nitrate by bioturbation, based on macrofauna distributions, could only account for the upper 10 cm depth of sediment. A several fold higher combined freeze-lysable KCl-extractable nitrate pool compared to porewater nitrate was detected. We hypothesised that his could be attributed to intracellular nitrate pools from nitrate accumulating microorganisms like Thioploca or Beggiatoa. However, pyrosequencing analysis did not detect any such organisms, leaving other bacteria, microbenthic algae, or foraminiferans which have also been shown to accumulate nitrate, as possible candidates. The importance and bioavailability of a KCl-extractable nitrate sediment pool remains to be tested. The significant variation in the vertical pattern and abundance of the various nitrate reducing genes phylotypes reasonably suggests differences in their activity throughout the sediment column. This raises interesting questions as to what the alternative metabolic roles for the various nitrate reductases could be, analogous to the alternative metabolic roles found for nitrite reductases

Metabolomic study of carotid-femoral pulse-wave velocity in women

Objective: Carotid-femoral pulse-wave velocity (PWV) is a measure of aortic stiffness that is strongly associated with increased risk of cardiovascular morbidity and mortality. The aim of the current study was to identify the molecular markers and the pathways involved in differences in PWV in women, in order to further understand the regulation of arterial stiffening. Methods: A total of 280 known metabolites were measured in 1797 female twins (age range: 18-84 years) not on any antihypertensive medication. Metabolites associated with PWV (after adjustment for age, BMI, metabolite batch, and family relatedness) were entered into a backward linear regression. Transcriptomic analyses were further performed on the top compounds identified. Results: Twelve metabolites were associated with PWV (P<1.8-10-4). One of the most strongly associated metabolites was uridine, which was not associated with blood pressure (BP) and traditional risk factors but correlated significantly with the gene-expression levels of the purinergic receptor P2RY2 (Beta=0.010, SE=0.003, P=0.007), suggesting that it may play a role in regulating endothelial nitric oxide synthase phosphorylation. On the other hand, phenylacetylglutamine was strongly associated with both PWV and BP. Conclusion: Circulating levels of uridine, phenylacetylglutamine, and serine appear strongly correlated with PWV in women

APPLE-Tree (Active Prevention in People at risk of dementia: Lifestyle, bEhaviour change and Technology to REducE cognitive and functional decline) programme: protocol

Background: Observational studies indicate that approximately a third of dementia cases are attributable to modifiable cardiometabolic, physical and mental health, and social and lifestyle risk factors. There is evidence that intensive behaviour change interventions targeting these factors can reduce cognitive decline. / Methods and analysis: We will design and test a low intensity, secondary dementia‐prevention programme (Active Prevention in People at risk of dementia: Lifestyle, bEhaviour change and Technology to REducE cognitive and functional decline, “APPLE‐Tree”) to slow cognitive decline in people with subjective cognitive decline with or without objective cognitive impairment. We will embed our work within social science research to understand how dementia prevention is currently delivered and structured. We will carry out systematic reviews and around 50 qualitative interviews with stakeholders, using findings to coproduce the APPLE‐Tree intervention. We plan a 10‐session group intervention, involving personalised goal‐setting, with individual sessions for those unable or unwilling to attend groups, delivered by psychology assistants who will be trained and supervised by clinical psychologists. The coproduction group (including public and patient involvement [PPI], academic and clinical/third‐sector professional representatives) will use the Behaviour Change Wheel theoretical framework to develop it. We will recruit and randomly allocate 704 participants, 1:1 to the intervention: informational control group. This sample size is sufficient to detect a between‐group difference at 2 years of 0.15 on the primary outcome (cognition: modified neuropsychological test battery; 90% power, 5% significance, effect size 0.25, SD 0.6). / Dissemination: We will work with Public Health England and third‐sector partners to produce an effective national implementation approach, so that if our intervention works, it is used in practice

Extreme drought pushes stream invertebrate communities over functional thresholds

Functional traits are increasingly being used to predict extinction risks and range shifts under long‐term climate change scenarios, but have rarely been used to study vulnerability to extreme climatic events, such as supraseasonal droughts. In streams, drought intensification can cross thresholds of habitat loss, where marginal changes in environmental conditions trigger disproportionate biotic responses. However, these thresholds have been studied only from a structural perspective, and the existence of functional nonlinearity remains unknown. We explored trends in invertebrate community functional traits along a gradient of drought intensity, simulated over 18 months, using mesocosms analogous to lowland headwater streams. We modelled the responses of 16 traits based on a priori predictions of trait filtering by drought, and also examined the responses of trait profile groups (TPGs) identified via hierarchical cluster analysis. As responses to drought intensification were both linear and nonlinear, generalized additive models (GAMs) were chosen to model response curves, with the slopes of fitted splines used to detect functional thresholds during drought. Drought triggered significant responses in 12 (75%) of the a priori‐selected traits. Behavioural traits describing movement (dispersal, locomotion) and diet were sensitive to moderate‐intensity drought, as channels fragmented into isolated pools. By comparison, morphological and physiological traits showed little response until surface water was lost, at which point we observed sudden shifts in body size, respiration mode and thermal tolerance. Responses varied widely among TPGs, ranging from population collapses of non‐aerial dispersers as channels fragmented to irruptions of small, eurythermic dietary generalists upon extreme dewatering. Our study demonstrates for the first time that relatively small changes in drought intensity can trigger disproportionately large functional shifts in stream communities, suggesting that traits‐based approaches could be particularly useful for diagnosing catastrophic ecological responses to global change

Metabolomic Identification of a Novel Pathway of Blood Pressure Regulation Involving Hexadecanedioate

High blood pressure is a major contributor to the global burden of disease and discovering novel causal pathways of blood pressure regulation has been challenging. We tested blood pressure associations with 280 fasting blood metabolites in 3980 TwinsUK females. Survival analysis for all-cause mortality was performed on significant independent metabolites (P<8.9x10(-5)). Replication was conducted in 2 independent cohorts KORA (n=1494) and Hertfordshire (n=1515). Three independent animal experiments were performed to establish causality: (1) blood pressure change after increasing circulating metabolite levels in Wistar-Kyoto rats; (2) circulating metabolite change after salt-induced blood pressure elevation in spontaneously hypertensive stroke-prone rats; and (3) mesenteric artery response to noradrenaline and carbachol in metabolite treated and control rats. Of the15 metabolites that showed an independent significant association with blood pressure, only hexadecanedioate, a dicarboxylic acid, showed concordant association with blood pressure (systolic BP: [95% confidence interval], 1.31 [0.83-1.78], P=6.81x10(-8); diastolic BP: 0.81 [0.5-1.11], P=2.96x10(-7)) and mortality (hazard ratio [95% confidence interval], 1.49 [1.08-2.05]; P=0.02) in TwinsUK. The blood pressure association was replicated in KORA and Hertfordshire. In the animal experiments, we showed that oral hexadecanedioate increased both circulating hexadecanedioate and blood pressure in Wistar-Kyoto rats, whereas blood pressure elevation with oral sodium chloride in hypertensive rats did not affect hexadecanedioate levels. Vascular reactivity to noradrenaline was significantly increased in mesenteric resistance arteries from hexadecanedioate-treated rats compared with controls, indicated by the shift to the left of the concentration-response curve (P=0.013). Relaxation to carbachol did not show any difference. Our findings indicate that hexadecanedioate is causally associated with blood pressure regulation through a novel pathway that merits further investigation

An atlas of genetic influences on human blood metabolites

Genome-wide association scans with high-throughput metabolic profiling provide unprecedented insights into how genetic variation influences metabolism and complex disease. Here we report the most comprehensive exploration of genetic loci influencing human metabolism thus far, comprising 7,824 adult individuals from 2 European population studies. We report genome-wide significant associations at 145 metabolic loci and their biochemical connectivity with more than 400 metabolites in human blood. We extensively characterize the resulting in vivo blueprint of metabolism in human blood by integrating it with information on gene expression, heritability and overlap with known loci for complex disorders, inborn errors of metabolism and pharmacological targets. We further developed a database and web-based resources for data mining and results visualization. Our findings provide new insights into the role of inherited variation in blood metabolic diversity and identify potential new opportunities for drug development and for understanding disease

APPLE-Tree (Active Prevention in People at risk of dementia: Lifestyle, bEhaviour change and Technology to REducE cognitive and functional decline) programme: protocol

Background: Observational studies indicate that approximately a third of dementia cases are attributable to modifiable cardiometabolic, physical and mental health, and social and lifestyle risk factors. There is evidence that intensive behaviour change interventions targeting these factors can reduce cognitive decline. (Figure presented.) Our planned intervention [Colour figure can be viewed at wileyonlinelibrary.com]. Methods and analysis: We will design and test a low intensity, secondary dementia-prevention programme (Active Prevention in People at risk of dementia: Lifestyle, bEhaviour change and Technology to REducE cognitive and functional decline, “APPLE-Tree”) to slow cognitive decline in people with subjective cognitive decline with or without objective cognitive impairment. We will embed our work within social science research to understand how dementia prevention is currently delivered and structured. We will carry out systematic reviews and around 50 qualitative interviews with stakeholders, using findings to coproduce the APPLE-Tree intervention. We plan a 10-session group intervention, involving personalised goal-setting, with individual sessions for those unable or unwilling to attend groups, delivered by psychology assistants who will be trained and supervised by clinical psychologists. The coproduction group (including public and patient involvement [PPI], academic and clinical/third-sector professional representatives) will use the Behaviour Change Wheel theoretical framework to develop it. We will recruit and randomly allocate 704 participants, 1:1 to the intervention: informational control group. This sample size is sufficient to detect a between-group difference at 2 years of 0.15 on the primary outcome (cognition: modified neuropsychological test battery; 90% power, 5% significance, effect size 0.25, SD 0.6). Dissemination: We will work with Public Health England and third-sector partners to produce an effective national implementation approach, so that if our intervention works, it is used in practice

Isolation and Maintenance-Free Culture of Contractile Myotubes from Manduca sexta Embryos

Skeletal muscle tissue engineering has the potential to treat tissue loss and degenerative diseases. However, these systems are also applicable for a variety of devices where actuation is needed, such as microelectromechanical systems (MEMS) and robotics. Most current efforts to generate muscle bioactuators are focused on using mammalian cells, which require exacting conditions for survival and function. In contrast, invertebrate cells are more environmentally robust, metabolically adaptable and relatively autonomous. Our hypothesis is that the use of invertebrate muscle cells will obviate many of the limitations encountered when mammalian cells are used for bioactuation. We focus on the tobacco hornworm, Manduca sexta, due to its easy availability, large size and well-characterized muscle contractile properties. Using isolated embryonic cells, we have developed culture conditions to grow and characterize contractile M. sexta muscles. The insect hormone 20-hydroxyecdysone was used to induce differentiation in the system, resulting in cells that stained positive for myosin, contract spontaneously for the duration of the culture, and do not require media changes over periods of more than a month. These cells proliferate under normal conditions, but the application of juvenile hormone induced further proliferation and inhibited differentiation. Cellular metabolism under normal and low glucose conditions was compared for C2C12 mouse and M. sexta myoblast cells. While differentiated C2C12 cells consumed glucose and produced lactate over one week as expected, M. sexta muscle did not consume significant glucose, and lactate production exceeded mammalian muscle production on a per cell basis. Contractile properties were evaluated using index of movement analysis, which demonstrated the potential of these cells to perform mechanical work. The ability of cultured M. sexta muscle to continuously function at ambient conditions without medium replenishment, combined with the interesting metabolic properties, suggests that this cell source is a promising candidate for further investigation toward bioactuator applications