bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic resonance imaging of the brain used to detect early post‐partum activation of multiple sclerosis
Authors: Paavilainen T. , Kurki T. , Parkkola R. , Färkkilä M. , Salonen O. , Dastidar P. , Elovaara I. , Airas L.
Published: September 2007

Post‐partum relapses are a frequent phenomenon in multiple sclerosis (MS). The purpose of this study was to evaluate the timing and extent of new or growing T2‐lesions after delivery in a cohort of Finnish MS patients. In addition to serial magnetic resonance imaging (MRI), the patients were followed up clinically with determination of relapse rate and expanded disability status scale. The annualized relapse rate was decreased during the last trimester of pregnancy [mean 0.14, standard deviation (SD) 0.14] when compared with the time before pregnancy (mean 0.64, SD 0.14; P = 0.04) and to time post‐partum (mean 1.50, SD 0.45; P = 0.0002). New or enlarging lesions were detected in the post‐partum images in 14 of 28 patients. Gadolinium‐enhancing lesions in post‐partum MRI were present in eight of 13 patients. There was a significant increase in the number of T2‐lesions (P = 0.0009), in the total volume of MS‐lesions measured from fluid‐attenuated inversion recovery images (P = 0.0126) and in the number of diffusion weighted imaging hyperintense lesions (P = 0.0098) in the post‐partum images. The clinical results support the earlier findings of decreased disease activity in late pregnancy. The clinical and MRI findings indicate that post‐partum activation is an early and common phenomenon amongst mothers with MS.
Distribution and underground habitats of cave‐dwelling bats in China
Authors: Niu H. , Wang N. , Zhao L. , Liu J.
Published: September 2007

To understand the distribution and relative abundance of cave‐dwelling bats and to identify those sites that would be important for conservation of bat species, 25 underground sites that had not been previously surveyed were investigated in this 3‐year study (from December 2003 to April 2006) in Funiu Mountain of Henan province, China. Approximately 80 000 bats were recorded, representing 12 species. The most abundant species were Rhinolophus affinis, Miniopterus schreibersi and Hipposideros pratti. The roosts were evaluated for their conservation importance. The most important sites in the area are Yunhua and Nanzhao caves, which serve as hibernaculums and nursery roosts to c. 13 740 and 11 803 bats, respectively, representing seven species. By means of cluster and correspondence analysis, the distribution of bat species was different between the two sides of the mountain and was highly dependent on the size of the cave. The underground sites in the south region hosted c. 80% of the total bats, representing 11 species. The sites in the north region hosted 20% of the total bats, representing seven species. Presently, none of the caves in the region has adequate protection and some bat populations are under serious threat. Many large caves that contained large bat populations and several species of concern had been developed as tourist sites, and so some advice on protecting the most important local habitats was sought based on the assessment of the conservation status of underground sites. This paper presents basic data concerning the distribution of cave‐dwelling bats and the patterns of cave use on Funiu Mountain. The data will help local governments and policy‐makers develop suitable strategies to promote local tourisms while protecting important habitats of animal species.
Sulcal variability, stereological measurement and asymmetry of Broca's area on MR images
Authors: Keller Simon Sean , Highley John Robin , Garcia‐Finana Marta , Sluming Vanessa , Rezaie Roozbeh , Roberts Neil
Published: September 2007

Leftward volume asymmetry of the pars opercularis and pars triangularis may exist in the human brain, frequently referred to as Broca's area, given the functional asymmetries observed in this region with regard to language expression. However, post‐mortem and magnetic resonance imaging (MRI) studies have failed to consistently identify such a volumetric asymmetry. In the present study, an analysis of the asymmetry of sulco‐gyral anatomy and volume of this anterior speech region was performed in combination with an analysis of the morphology and volume asymmetry of the planum temporale, located within the posterior speech region, in 50 healthy subjects using MRI. Variations in sulcal anatomy were documented according to strict classification schemes and volume estimation of the grey matter within the brain structures was performed using the Cavalieri method of stereology. Results indicated great variation in the morphology of and connectivity between the inferior frontal, inferior precentral and diagonal sulci. There were significant inter‐hemispheric differences in the presence of (1) the diagonal sulcus within the pars opercularis, and (2) horizontal termination of the posterior Sylvian fissure (relative to upward oblique termination), both with an increased leftward incidence. Double parallel inferior precentral sulci and absent anterior rami of the Sylvian fissure prevented stereological measurements in five subjects. Therefore volumes were obtained from 45 subjects. There was a significant leftward volume asymmetry of the pars opercularis (P = 0.02), which was significantly related to the asymmetrical presence of the diagonal sulcus (P < 0.01). Group‐wise pars opercularis volume asymmetry did not exist when a diagonal sulcus was present in both or neither hemispheres. There was no significant volume asymmetry of the pars triangularis. There was a significant leftward volume asymmetry of the planum temporale (P < 0.001), which was significantly associated with the shape of the posterior Sylvian fissure as a unilateral right or left upward oblique termination was always associated with leftward or rightward volume asymmetry respectively (P < 0.01). There was no relationship between volume asymmetries of the anterior and posterior speech regions. Our findings illustrate the extent of morphological variability of the anterior speech region and demonstrate the difficulties encountered when determining volumetric asymmetries of the inferior frontal gyrus, particularly when sulci are discontinuous, absent or bifid. When the intrasulcal grey matter of this region is exhaustively sampled according to strict anatomical landmarks, the volume of the pars opercularis is leftward asymmetrical. This manuscript illustrates the importance of simultaneous consideration of brain morphology and morphometry in studies of cerebral asymmetry.
Soluble oligomers from a non‐disease related protein mimic Aβ‐induced tau hyperphosphorylation and neurodegeneration
Authors: Vieira Marcelo N. N. , Forny‐Germano Letícia , Saraiva Leonardo M. , Sebollela Adriano , Martinez Ana M. Blanco , Houzel Jean‐Christophe , De Felice Fernanda G. , Ferreira Sérgio T.
Published: September 2007

Protein aggregation and amyloid accumulation in different tissues are associated with cellular dysfunction and toxicity in important human pathologies, including Alzheimer’s disease and various forms of systemic amyloidosis. Soluble oligomers formed at the early stages of protein aggregation have been increasingly recognized as the main toxic species in amyloid diseases. To gain insight into the mechanisms of toxicity instigated by soluble protein oligomers, we have investigated the aggregation of hen egg white lysozyme (HEWL), a normally harmless protein. HEWL initially aggregates into β‐sheet rich, roughly spherical oligomers which appear to convert with time into protofibrils and mature amyloid fibrils. HEWL oligomers are potently neurotoxic to rat cortical neurons in culture, while mature amyloid fibrils are little or non‐toxic. Interestingly, when added to cortical neuronal cultures HEWL oligomers induce tau hyperphosphorylation at epitopes that are characteristically phosphorylated in neurons exposed to soluble oligomers of the amyloid‐β peptide. Furthermore, injection of HEWL oligomers in the cerebral cortices of adult rats induces extensive neurodegeneration in different brain areas. These results show that soluble oligomers from a non‐disease related protein can mimic specific neuronal pathologies thought to be induced by soluble amyloid‐β peptide oligomers in Alzheimer’s disease and support the notion that amyloid oligomers from different proteins may share common structural determinants that would explain their generic cytotoxicities.
NMDA‐mediated release of glutamate and GABA in the subthalamic nucleus is mediated by dopamine: an in vivo microdialysis study in rats
Authors: Ampe Ben , Massie Ann , D’Haens Jean , Ebinger Guy , Michotte Yvette , Sarre Sophie
Published: September 2007

The present study investigated the effects of N‐methyl‐D‐aspartic acid·H2O (NMDA) on the dopamine, glutamate and GABA release in the subthalamic nucleus (STN) by using in vivo microdialysis in rats. NMDA (100 μmol/L) perfused through the microdialysis probe evoked an increase in extracellular dopamine in the STN of the intact rat of about 170%. This coincided with significant increases in both extracellular glutamate (350%) and GABA (250%). The effect of NMDA perfusion on neurotransmitter release at the level of the STN was completely abolished by co‐perfusion of the selective NMDA‐receptor antagonist MK‐801 (10 μmol/L), whereas subthalamic perfusion of MK‐801 alone had no effect on extracellular neurotransmitter concentrations. Furthermore, NMDA induced increases in glutamate were abolished by both SCH23390 (8 μmol/L), a selective D1 antagonist, and remoxipride (4 μmol/L), a selective D2 antagonist. The NMDA induced increase in GABA was abolished by remoxipride but not by SCH23390. Perfusion of the STN with SCH23390 or remoxipride alone had no effect on extracellular neurotransmitter concentrations. The observed effects in intact animals depend on the nigral dopaminergic innervation, as dopamine denervation, by means of 6‐hydroxydopamine lesioning of the substantia nigra, clearly abolished the effects of NMDA on neurotransmitter release at the level of the STN. Our work points to a complex interaction between dopamine, glutamate and GABA with a crucial role for dopamine at the level of the STN.
Characterization of the adaptor protein ARH expression in the brain and ARH molecular interactions
Authors: Mameza Marie Germaine , Lockard Jon M. , Zamora Eduardo , Hillefors Mi , Lavina Zeno Scotto , Kaplan Barry B.
Published: September 2007

Previously, pA134 was identified as one of the mRNAs present in the squid giant axon. Comparative sequence analyses revealed that the pA134 gene product manifested significant similarity to the mammalian lipoprotein receptor adaptor protein also known as ARH (autosomal recessive hypercholesterolemia). ARH mRNA and protein displayed very similar pattern of expression throughout the mouse brain. Significant levels of expression were observed in cells with a predominantly neuronal profile in the cerebellum, brainstem, olfactory bulb, hippocampus, and cortex. A yeast two hybrid screen for ARH protein interactions in mouse brain identified the following binders: amyloid precursor‐like protein 1, low density lipoprotein receptor‐related protein (LRP) 1, LRP8, and GABA receptor‐associated protein‐like 1. The interactions of ARH with LRP1 and GABA receptor‐associated protein‐like 1 were subsequently verified by co‐immunoprecipitation of the protein complexes from transfected human embryonic kidney cells. The presence of ARH mRNA in axon of primary sympathetic neurons was established by RT‐PCR analyses and confirmed by in situ hybridization. Taken together, our data suggest that ARH is a multifunctional protein whose spectrum of function in the brain goes beyond the traditionally known metabolism of lipoproteins, and that ARH may be locally synthesized in the axon.
Phosphorylation and activation of tryptophan hydroxylase 2: identification of serine‐19 as the substrate site for calcium, calmodulin‐dependent protein kinase II
Authors: Kuhn Donald M. , Sakowski Stacey A. , Geddes Timothy J. , Wilkerson Curtis , Haycock John W.
Published: September 2007

Tryptophan hydroxylase (TPH) is the initial and rate‐limiting enzyme in the biosynthesis of serotonin. TPH was once thought to be a single‐gene product but it is now known to exist in two isoforms. TPH1 is found in the periphery and pineal gland whereas TPH2 is expressed specifically in the CNS. Both TPH isoforms are known to be regulated by protein kinase‐dependent phosphorylation and the sites of modification of TPH1 by protein kinase A have been identified. While TPH2 is activated by calcium, calmodulin‐dependent protein kinase II (CaMKII), the sites at which this isoform is modified are not known. Treatment of wild‐type TPH2 with CaMKII followed by mass spectrometry analysis revealed that the enzyme was activated and phosphorylated at a single site, serine‐19. Mutagenesis of serine‐19 to alanine did not alter the catalytic function of TPH2 but this mutant enzyme was neither activated nor phosphorylated by CaMKII. A phosphopeptide bracketing phosphoserine‐19 in TPH2 was used as an antigen to generate polyclonal antibodies against phosphoserine‐19. The antibodies are highly specific for phosphoserine‐19 in TPH2. The antibodies do not react with wild‐type TPH2 or TPH1 and they do not recognize phophoserine‐58 or phosphoserine‐260 in TPH1. These results establish that activation of TPH2 by CaMKII is mediated by phosphorylation of serine‐19 within the regulatory domain of the enzyme. Production of a specific antibody against the CaMKII phosphorylation site in TPH2 represents a valuable tool to advance the study of the mechanisms regulating the function of this important enzyme.
Single molecule profiling of tau gene expression in Alzheimer’s disease
Authors: Conrad Chris , Zhu Jun , Conrad Cintia , Schoenfeld David , Fang Zhide , Ingelsson Martin , Stamm Stefan , Church George , Hyman Bradley T.
Published: September 2007

Tau is a microtubule‐associated protein that is important for establishing and maintaining neuronal morphology. In addition to its role in normal cells, tau protein is involved in many neurodegenerative diseases, e.g. Alzheimer’s disease (AD) and frontotemporal dementia, as the main component of intraneuronal aggregates. Alternative splicing of tau gene in the brain can give rise to at least six protein variants. A causative role of skewed tau exon 10 inclusion has been defined in frontotemporal dementia; however, no link was established between the aberrant splicing of tau and AD. Here, we applied a single‐molecule‐based technology, polymerase colony or polony, to simultaneously monitor tau splicing variant and haplotype profile in sporadic AD and normal brains. We found that the coordinated expression of tau exons 2 and 10 is altered in AD. Additional investigations of cis and trans mechanisms of this observation revealed a decreased protein expression of a known tau splicing factor, htra2‐beta‐1 in AD, thereby implicating a trans mechanism. Our results demonstrate that dysregulation of combinatorial splicing might serve as a signature for aging‐related diseases, and the polony assay could be widely adapted for the study of other tauopathies. Furthermore, splicing‐based therapeutics is an emerging area of drug development, and a well‐defined and quantitative assay for monitoring single‐gene transcriptome will be relevant for such development.
Nuclear factor‐κB regulates seizure threshold and gene transcription following convulsant stimulation
Authors: Lubin Farah D. , Ren Yajun , Xu Xianghua , Anderson Anne E.
Published: September 2007

We evaluated a role for the nuclear factor‐kappa B (NF‐κB) pathway in the regulation of seizure susceptibility and transcriptional activation during prolonged, continuous seizures (status epilepticus). Using two functionally distinct NF‐κB inhibitors we observed a decrease in latency to onset of kainate‐induced seizures and status epilepticus. To assess NF‐κB transcriptional activation, we evaluated inhibitor kappa B alpha (IκBα) and brain‐derived neurotrophic factor (bdnf) gene targets. Inhibition of the NF‐κB signaling pathway significantly attenuated the increases in IκBα and bdnf mRNA levels that occurred during prolonged seizure activity, suggesting that the NF‐κB pathway was involved in the up‐regulation of these transcripts during status epilepticus. DNA‐binding studies and chromatin immunoprecipitation assays using hippocampal extracts from animals with status epilepticus revealed that NF‐κB subunits were associated with the candidate κB‐binding elements within promoter 1 of the bdnf gene. The pattern of association was different for the p50 and p65 subunits supporting complex NF‐κB modifications within promoter 1. In summary, our findings provide additional insights into the role of NF‐κB transcriptional regulation in hippocampus following status epilepticus and suggest that NF‐κB pathway activation contributes to seizure susceptibility.
Neuroprotection and stroke: time for a compromise
Authors: Young Alan R. , Ali Carine , Duretête Arnaud , Vivien Denis
Published: September 2007

In April 2007, there existed a repertory of 286 trials concerned with acute ischemic stroke on the Stroke Trials Registry (http://www.strokecenter.org/trials/), of which 209 trials were considered as complete (with no evidence of patient benefit unless one considers the much hard fought for and modest results of the tPA studies). Among other questions arising from such failures, one can wonder whether the plethora of pharmacological agents that exhibited neuroprotective properties in pre‐clinical studies were selected for clinical trials entirely based upon their experimental efficacy. This mini‐review will try to point out some of the weaknesses that could underline the failure of both researchers and clinicians involved in the field of stroke to obtain their ultimate goal – brain protection.
Formyl peptide‐receptor like‐1 requires lipid raft and extracellular signal‐regulated protein kinase to activate inhibitor‐κB kinase in human U87 astrocytoma cells
Authors: Kam Angel Y. F. , Liu Andrew M. F. , Wong Yung H.
Published: September 2007

Formyl peptide‐receptor like‐1 (FPRL‐1) may possess critical roles in Alzheimer’s diseases, chemotaxis and release of neurotoxins, possibly through its regulation of nuclear factor‐κB (NFκB). Here we illustrate that activation of FPRL‐1 in human U87 astrocytoma or Chinese hamster ovary cells stably expressing the receptor resulted in the phosphorylations of inhibitor‐κB kinase (IKK), an onset kinase for NFκB signaling cascade. FPRL‐1 selective hexapeptide Trp‐Lys‐Tyr‐Met‐Val‐Met (WKYMVM) promoted IKK phosphorylations in time‐ and dose‐dependent manners while pre‐treatment of pertussis toxin abrogated the Gαi/o‐dependent stimulations. The FPRL‐1‐mediated IKK phosphorylation required extracellular signal‐regulated protein kinase (ERK), phosphatidylinositol 3‐kinase and cellular Src (c‐Src), but not c‐Jun N‐terminal kinase and p38 mitogen‐activated protein kinase. Despite its ability to mobilize Ca2+, WKYMVM did not require Ca2+for the modulation of IKK phosphorylation. Activation of FPRL‐1 also induced NFκB‐driven luciferase expression. Interestingly, cholesterol depletion from plasma membrane by methyl‐β‐cyclodextrin abolished the FPRL‐1‐stimulated IKK phosphorylation, denoting the important role of lipid raft integrity in the FPRL‐1 to IKK signaling. Furthermore, we demonstrated that in U87 cells, several signaling intermediates in the FPRL‐1‐IKK pathway including Gαi2, c‐Src and ERK were constitutively localized at the raft microdomains. WKYMVM administration not only resulted in higher amount of ERK recruitment to the raft region, but also specifically stimulated raft‐associated c‐Src and ERK phosphorylations. Taken together, these results demonstrate that FPRL‐1 is capable of activating NFκB signaling through IKK phosphorylation and this may serve as a useful therapeutical target for FPRL‐1‐related diseases.
Magnetic resonance analysis of the effects of acute ammonia intoxication on rat brain. Role of NMDA receptors
Authors: Cauli Omar , López‐Larrubia Pilar , Rodrigues Tiago B. , Cerdán Sebastián , Felipo Vicente
Published: September 2007

Acute ammonia intoxication leads to rapid death, which is prevented by blocking N‐methyl‐d‐aspartate (NMDA) receptors. The subsequent mechanisms leading to death remain unclear. Brain edema seems an important step. The aim of this work was to study the effects of acute ammonia intoxication on different cerebral parameters in vivo using magnetic resonance and to assess which effects are mediated by NMDA receptors activation. To assess edema induction, we injected rats with ammonium acetate and measured apparent diffusion coefficient (ADC) in 16 brain areas. We also analyzed the effects on T1, T2, and T2* maps and whether these effects are prevented by blocking NMDA receptors. The effects of acute ammonia intoxication are different in different brain areas. T1 relaxation time is reduced in eight areas. T2 relaxation time is reduced only in ventral thalamus and globus pallidus. ADC values increased in hippocampus, caudate‐putamen, substantia nigra and cerebellar cortex, reflecting vasogenic edema. ADC decreased in hypothalamus, reflecting cytotoxic edema. Myo‐inositol increased in cerebellum and substantia nigra, reflecting vasogenic edema. N‐acetyl‐aspartate decreased in cerebellum, reflecting neuronal damage. Changes in N‐acetyl‐aspartate, T1 and T2 are prevented by blocking NMDA receptors with MK‐801 while changes in ADC or myo‐inositol (induction of edema) are not.
Cell death in an ischemic infarct rim model
Authors: Yao Hang , Sun Xiaolu , Gu Xiang , Wang Juan , Haddad Gabriel G.
Published: September 2007

Using an in vitro model that simulates the microenvironment in the ischemic infarct rim, we have examined the temporal profile and possible mechanisms of cell death in the neuropil (an astrocyte‐rich area or ARA) of organotypic hippocampal slice cultures. Two‐photon confocal microscopy, propidium iodide, and GFAP‐GFP transgenic mice were used to confirm cell death in astrocytes. An ‘ischemic solution’ (IS) induced major cell death throughout the hippocampus over 24 h, with the earliest injury starting in ARA. Our studies using IS or ion replacements in IS revealed that cell death in ARA was modest when K+ was increased or pH lowered. High K+ is most effective in reducing cell death when HCO3− is normal or high. When Cl− or HCO3− was reduced, cell injury was worsened. 4,4′‐diisothiocyanatostilbene‐2,2′‐disulfonic acid (DIDS) protected cells from IS‐induced death in a dose‐dependent manner (1–4000 μmol/L). We conclude that (i) various areas of the hippocampal formation respond differently to ionic replacements; (ii) K+ interacts with other ions to protect cells in ARA; and (iii) DIDS has a substantial protective effect in ARA by blocking DIDS‐sensitive membrane exchangers or by interfering with intracellular signaling pathways.
Aldose reductase is implicated in high glucose‐induced oxidative stress in mouse embryonic neural stem cells
Authors: Fu Jiang , Tay S. S. W. , Ling E. A. , Dheen S. T.
Published: September 2007

Oxidative stress caused by hyperglycemia is one of the key factors responsible for maternal diabetes‐induced congenital malformations, including neural tube defects in embryos. However, mechanisms by which maternal diabetes induces oxidative stress during neurulation are not clear. The present study was aimed to investigate whether high glucose induces oxidative stress in neural stem cells (NSCs), which compose the neural tube during development. We also investigated the mechanism by which high glucose disturbs the growth and survival of NSCs in vitro. NSCs were exposed to physiological d‐glucose concentration (PG, 5 mmol/L), PG with l‐glucose (25 mmol/L), or high d‐glucose concentration (HG, 30 or 45 mmol/l). HG induced reactive oxygen species production and mRNA expression of aldose reductase (AR), which catalyzes the glucose reduction through polyol pathway, in NSCs. Expression of glucose transporter 1 (Glut1) mRNA and protein which regulates glucose uptake in NSCs was increased at early stage (24 h) and became down‐regulated at late stage (72 h) of exposure to HG. Inhibition of AR by fidarestat, an AR inhibitor, decreased the oxidative stress, restored the cell viability and proliferation, and reduced apoptotic cell death in NSCs exposed to HG. Moreover, inhibition of AR attenuated the down‐regulation of Glut1 expression in NSCs exposed to HG for 72 h. These results suggest that the activation of polyol pathway plays a role in the induction of oxidative stress which alters Glut1 expression and cell cycle in NSCs exposed to HG, thereby resulting in abnormal patterning of the neural tube in embryos of diabetic pregnancy.
PERMANENT GENETIC RESOURCES: Characterization of eight microsatellite loci in the woolly mouse opossum, Micoureus paraguayanus, isolated from Micoureus demerarae
Authors: DIAS I. M. G. , AMATO G. , CARVALHO M. R. S. , CUNHA H. M. , PAGLIA A. P. , DESALLE R. , FONSECA C. G.
Published: September 2007

Eight novel microsatellite markers were isolated from the woolly mouse opossum from the Amazon Forest in Peru, Micoureus demerarae, using a partial genomic DNA library and an enrichment protocol. These loci were polymorphic in M. demerarae and Micoureus paraguayanus populations from the Atlantic Forest in Brazil with the number of alleles ranging from two to 23. Those eight loci plus another five already described for M. paraguayanus will allow for the evaluation of genetic diversity of populations from the ‘Rio Doce’ Park, one of the last Atlantic Forest fragments in Minas Gerais state, Brazil.
PERMANENT GENETIC RESOURCES: A set of 12 microsatellite loci for genetic studies of Leishmania braziliensis
Authors: ROUGERON V. , WALECKX E. , HIDE M. , DE MEEÛS T. , AREVALO J. , LLANOS‐CUENTAS A. , BAÑULS A. L.
Published: September 2007

Twelve microsatellite loci of Leishmania braziliensis were examined, nine of which were developed in this work. Fifty‐six Leishmania braziliensis were genotyped with these microsatellite loci. The 12 loci studied were polymorphic with the number of alleles ranging from five to 19, with a mean of 9.7 ± 4.1 and the observed heterozygosity averaging 0.425 ± 0.202. The important heterozygote deficits we observed (FIS = 0.41, P value = 0.004) appear incompatible with the heterozygote excess expected in clonal diploids. This last result could revive the clonality/sexuality debate regarding Leishmania. This work validates the potential use of these microsatellites for population genetics analysis.
Effects of tillage and reseeding on phosphorus transfers from grassland
Authors: Butler P. J. , Haygarth P. M.
Published: September 2007

Pasture tillage and reseeding is part of the normal rotation cycle of grassland systems in the UK and a process that could increase the rate of phosphorus (P) transfer to water, thus potentially contributing to eutrophication. The effect of tillage and reseeding on P transfer was investigated at two scales: from drained and undrained 1 ha hydrologically isolated pasture plots within the Rowden Drainage Experiment in Devon, during a 6‐month winter drainage period in 1998–1999, and in replicated soil box experiments during simulated rainfall ‘events’. At the plot scale, total P exports of 3.75 kg P ha−1 were determined over a 16‐day period, indicating that soil and P were most vulnerable to detachment and mobilization during rainfall and run‐off in this period. Once the sward had developed, and the vulnerability to soil detachment reduced, reseeded swards with pipe drainage transferred less P (approx. 0.3 kg P ha−1 yr−1) to water than is commonly measured on permanent grassland (approx. 1 kg P ha−1 yr−1). Soil box experiments showed that tilled soil transferred more P > 0.45 μm but P < 0.45 μm was retained. Sward cover is critical to reducing detachment and resulting P transfer from surface soil, and therefore careful consideration should be taken for the need to reseed. The effects of tillage and reseeding on phosphorus transfers from grassland can be potentially significant and ought to be mitigated against using low‐till practices to reduce potential contribution to water quality.
Soil texture effects on the transport of phosphorus from agricultural land in river deltas of Northern Belgium, The Netherlands and North‐West Germany
Authors: Chardon W. J. , Schoumans O. F.
Published: September 2007

The loss of phosphorus (P) from agricultural soils can lead to serious eutrophication of surface water. Within the large river delta areas in Northern Belgium, The Netherlands and North‐West Germany, a number of representative soil textures are found (sandy, peaty and clayey soils), each with its own specific combination of pathways for P loss. Based on a literature review, this paper describes for these areas the main eutrophication issues and the factors affecting P loss from these agricultural soils. Aspects of P input, legislation and water quality are discussed. On sandy soils, intensive animal production systems have led to the localized build‐up of P in the soil profile with subsequent leaching to shallow groundwaters, and seepage into surface waters. Regulations for production and application of manure on these soils have led to improvements in surface water quality in the last decade, but P concentrations are still too high to maintain satisfactory ecological standards in water. On peat soils, the mineralization of organic matter in the topsoil or in the subsoil can release large amounts of P, leading to high concentrations of P in surface water. However, large P losses can also occur in seepage water from peat deposits in marine sediments containing easily‐soluble calcareous P minerals. On clays, incidental losses of P are dominant: surface runoff or preferential flow can lead to loss of freshly applied P, even from soils that are known to have a large retention capacity for P.
Agriculture as a source of phosphorus causing eutrophication in Central and Eastern Europe
Authors: Csathó P. , Sisák I. , Radimszky L. , Lushaj S. , Spiegel H. , Nikolova M. T. , Nikolov N. , ČErmák P. , Klir J. , Astover A. , Karklins A. , Lazauskas S. , Kopiński J. , Hera C. , Dumitru E. , Manojlovic M. , Bogdanović D. , Torma S. , Leskošek M. , Khristenko A.
Published: September 2007

There are considerable differences between the EU‐15 countries and Central and Eastern European (CEE) countries in the application rate of phosphorus (P) fertilizer and manure as well as in the climate and erosion patterns, but the eutrophication of surface waters is a common problem. The availability of information on the contribution of the CEE countries to European surveys on eutrophication is not adequate, because the amount of data available from these countries is small. There is thus a need to compile more comprehensive data sets for better assessment. Recent changes in agricultural practices, and their impact on the trophic status of surface waters in CEE countries, have been evaluated using a few selected pressure and state indicators (phosphorus balance, phosphorus status and erosion of agricultural land, P loss risk index, chlorophyll a, total and orthophosphate content of water) by compiling and analysing data from the literature. In the CEE countries, small annual P balances (−7 to +6 kg P ha−1) and declining levels of soil available P (proportion of soils adequately supplied with P dropped to between 10 and 50% of total area) may lead to low yields and economic difficulties. Only 11% of the variation in total phosphorus (TP) in rivers studied could be attributed to the calculated P loss risk index, and thus to the impact of differences in the agricultural diffuse source P load. The generation of more consistent data sets should be pursued for the whole of Europe in order to derive more powerful indicators. A refined P index could be one of the best indicators of eutrophication. Recent changes in the trophic level of surface waters could be attributed to a large extent to the change in point source P loads, i.e. to the diminishing amount of P load from municipal and industrial wastewater. The short‐term improvement of water quality in the CEE countries will require further improvements in wastewater treatment, but long‐term improvement will only be achieved by reducing diffuse P losses from agriculture, possibly involving changes in the land use pattern and in farming practices.
Linking phosphorus sources to impacts in different types of water body
Authors: Edwards A. C. , Withers P. J. A.
Published: September 2007

The inherent variability in type, composition and modes of transport/delivery of the various sources of phosphorus (P) contribute to the complex temporal and spatial patterns of P concentrations and loads reaching freshwaters. One particularly useful and common distinction is made between diffuse sources that are hydrologically driven and therefore episodic and seasonal, compared with the more bioavailable, concentrated and continuous P discharges from discrete point sources. In terms of ecological impacts, well‐distributed rural point sources (village wastewater, septic tank overflows and farmyards) that discharge into smaller tributaries may be further separated from the more isolated large urban wastewater and industrial effluent discharges to larger waters. Impacts of diffuse sources may be similarly broken down into near‐surface and base flow (groundwater) contributions. These differences in mechanisms of delivery, when coupled with differences in chemical form (and therefore availability) of P, combine to influence in‐stream processes, kinetics of downstream transport and potential impacts. A greater understanding of the specific attributes that are responsible for controlling the dynamics of a particular P source together with some idea of its environmental relevance would help prioritize and target remedial actions. In particular, the extent to which periods of P supply overlap with those of biological demand help determine the relative significance of individual P sources and could inform programmes of measures to control P loss from these sources more effectively. The lack of any provision for interpreting P supply within an ecological context might result in poor relationships between reductions in P loading and environmental benefit.
Variation in the reactive phosphorus concentrations in rivers of northwest Europe with respect to their potential to cause eutrophication
Authors: Foy R. H.
Published: September 2007

By 2002, there had been a variable implementation of phosphorus (P) removal at waste water treatment works in a set of countries in northwest Europe; ranging from close to 100% of the urban populations in Austria, Denmark, Finland, Germany, the Netherlands and Sweden to between 2% and 56% of the inland urban populations in Belgium, France, Ireland and the UK. This variable application has resulted in a proportional lowering of reactive phosphorus (RP) concentrations in rivers. Thus, although the inland urban population density of Germany exceeds that of the UK (207 vs. 148 persons km−2), mean RP in 2004 was lower in German rivers (75 vs. 265 μg P L−1). By adjusting urban populations downwards by the P equivalent populations removed through tertiary treatment, the resulting effective urban population density was strongly and positively correlated with mean river RP concentration (r = 0.99) and the percentage of rivers with average RP >100 μg P L−1 (r = 0.98). Two agricultural variables, the agricultural area as a percentage of total area and the application of P in manures and fertilizers to the national land area were uncorrelated with either mean or median RP concentrations but were negatively correlated with the proportion of rivers with low mean concentrations of RP (<25 μg P L−1). Phosphorus discharges associated with urban populations remains the strongest driver of a time‐weighted variable such as average RP concentration, although agricultural variables may exert a stronger influence on flow‐weighted concentrations or loadings of RP.
Sourcing, transport and control of phosphorus loss in two English headwater catchments
Authors: Hodgkinson R. A. , Withers P. J. A.
Published: September 2007

Long‐term data on annual phosphorus (P) transfers from an intensively under‐drained largely arable catchment (Rosemaund) and a less intensively drained mixed arable/dairy catchment (Cliftonthorpe) are presented and compared. The range in stream loads of total P (TP) from both catchments was very similar (0.1–4.2 kg ha−1 year−1) and dominated by the particulate (PP) form. At Rosemaund, the majority (approx. 55%) of the P was transferred through pipe drains. The PP transfers in overland flow from arable fields at Rosemaund were estimated to be three times those from extensive grassland and the contribution of hopyards was over 10 times that of arable land. Changing land use from arable to grass at Rosemaund reduced flow and P loss through pipe drains, especially in the third year after establishment. By contrast, at Cliftonthorpe, only 33% of the TP transfer was through pipe drains and PP transfers in overland flow from grassland were estimated to be twice that from arable land. The increased P transfer from grassland was related to livestock poaching mobilizing P on wet riparian fields. However, establishment of a 6‐m riparian grass buffer strip at Cliftonthorpe had no beneficial effect on TP transfer over a 3‐year period and tended to increase the proportion of P transferred in soluble form. Our data highlight the large variability in P loss risk due to land management rather than land use per se, and the potential for PP transfer to occur from grassland as well as from arable land. More long‐term research is needed to fully evaluate the effectiveness of control options in catchments.
An environmental soil test to estimate the intrinsic risk of sediment and phosphorus mobilization from European soils
Authors: Withers P. J. A. , Hodgkinson R. A. , Barberis E. , Presta M. , Hartikainen H. , Quinton J. , Miller N. , Sisák I. , Strauss P. , Mentler A.
Published: September 2007

Methodologies are required to help identify soils that are vulnerable to both suspended sediment (SS) and phosphorus (P) transfer in land run‐off to combat the adverse impacts of agriculture on water quality. A laboratory test that quantifies dispersed particles and associated P in the same suspension was developed to estimate the potential mobilization of SS and P due to rainfall impact from 26 European soils with varied soil physical and chemical properties and P inputs. The test recovers an aliquot of the clay and fine silt (<20 μm) fraction of soils after gently shaking in distilled water for 1 min at a 1:50 soil‐to‐solution ratio and measures the dry residue, total P and dissolved (<0.45 μm) P content. The results of the test correlated well (r2 = 0.7–0.8) with the amounts of SS, total P and dissolved P in overland flow generated by indoor simulated rainfall (intensity 60 mm h−1 for 30 min and a 5° slope). Variation in SS and particulate P mobilization was linked to soil pH, organic matter (or clay) and sesquioxide content, although a multiple regression analysis showed these factors accounted for no more than 55% of this variation. Ranking showed that the soils generating the most sediment did not necessarily generate the most P loss due to variable degrees of P enrichment of the particulate fraction and variable contributions of dissolved P. Particulate P enrichment was related weakly (r2 = 0.5) to soil total P, while dissolved P fractions were predicted well (r2 = 0.8–0.9) by conventional soil P tests (water and Olsen). The environmental soil test has a potential role in identifying the comparative risk of sediment and P mobilization from critical source areas connected via both surface and subsurface pathways, and in providing data for incorporation into models predicting sediment and P transfer at the field and catchment scale.
Using critical source areas for targeting cost‐effective best management practices to mitigate phosphorus and sediment transfer at the watershed scale
Authors: Strauss P. , Leone A. , Ripa M. N. , Turpin N. , Lescot J.‐M. , Laplana R.
Published: September 2007

The impact of implementing different best management practices (BMPs) at the small watershed scale were examined for the Petzenkirchen catchment in Austria and Lake Vico in Italy, in terms of data needs, hydrological processes, tools and models involved. Identification of critical source areas for targeting soil and phosphorus losses turned out to be crucial for correct allocation of BMPs. Comparison of environmental effectiveness and costs, both calculated using various modelling approaches, enabled us to compare different levels of introducing BMPs ecologically and economically. Within each catchment, small areas of land tended to be the source of disproportionately large amounts of pollution. Therefore, confining mitigation to these areas costs less than targeting wider areas. This suggests that a policy for environmental programmes should be focussed on hydrological units and critical source areas within these units instead of introducing universal controls – the ‘watering can’ principle – as practised today.
Appraisal of phosphorus and sediment transfer in three pilot areas identified for the catchment sensitive farming initiative in England: application of the prototype PSYCHIC model
Authors: Collins A. L. , Strőmqvist J. , Davison P. S. , Lord E. I.
Published: September 2007

The England Catchment Sensitive Farming Delivery Initiative has recently identified 40 priority catchments where stakeholders require assistance with tackling harmful diffuse pollution, including that associated with phosphorus (P) and sediment. Newly appointed Catchment Sensitive Farming Officers require appropriate means of targeting P and sediment mitigation methods. In this context, the prototype PSYCHIC (Phosphorus and Sediment Yield CHaracterization In Catchments) model was used to characterize three pilot catchments in England, namely: the Derwent‐Cocker (626 km2), Teme (1623 km2) and Wensum (689 km2). Modelled annual total P export from the Derwent‐Cocker catchment is 1.2 kg ha−1 year−1, compared with 0.6 kg ha−1 year−1from the Teme catchment and 0.9 kg ha−1 year−1from the Wensum catchment. Corresponding sediment export is predicted at 271 kg ha−1 year−1, 124 kg ha−1 year−1and 70 kg ha−1 year−1, respectively. The findings highlight the importance of factors including P application rates, soil types and the increased connectivity provided by assisted drainage in determining pollution ‘hotspots’. Model output is being used to engage stakeholders and devise abatement strategies.
Land use scenarios for England and Wales: evaluation of management options to support ‘good ecological status’ in surface freshwaters
Authors: Johnes P. J. , Foy R. , Butterfield D. , Haygarth P. M.
Published: September 2007

This paper analyses historic records of agricultural land use and management for England and Wales from 1931 and 1991 and uses export coefficient modelling to hindcast the impact of these practices on the rates of diffuse nitrogen (N) and phosphorus (P) export to water bodies for each of the major geoclimatic regions of England and Wales. Key trends indicate the importance of animal agriculture as a contributor to the total diffuse agricultural nutrient loading on waters, and the need to bring these sources under control if conditions suitable for sustaining ‘Good Ecological Status’ under the Water Framework Directive are to be generated. The analysis highlights the importance of measuring changes in nutrient loading in relation to the catchment‐specific baseline state for different water bodies. The approach is also used to forecast the likely impact of broad regional scale scenarios on nutrient export to waters and highlights the need to take sensitive land out of production, introduce ceilings on fertilizer use and stocking densities, and controls on agricultural practice in higher risk areas where intensive agriculture is combined with a low intrinsic nutrient retention capacity, although the uncertainties associated with the modelling applied at this scale should be taken into account in the interpretation of model output. The paper advocates the need for a two‐tiered approach to nutrient management, combining broad regional policies with targeted management in high risk areas at the catchment and farm scale.
Evaluation of contrasting buffer features within an agricultural landscape for reducing sediment and sediment‐associated phosphorus delivery to surface waters
Authors: Owens P. N. , Duzant J. H. , Deeks L. K. , Wood G. A. , Morgan R. P. C. , Collins A. J.
Published: September 2007

There are a variety of buffering features within the landscape that can be used to trap sediment and associated contaminants such as phosphorus (P), thereby helping to reduce sediment and P delivery to watercourses. Astroturf mats (n = 136) were placed within contrasting buffer features at nine sites [mid‐field hedges (two sites), edge‐of‐field grass strips (six sites) and channel wetlands (one site)] within the River Parrett basin in England. Sediment was recorded on the mats at seven of the sites during the 18‐month sampling period. At the other two sites either there was insufficient erosion or sediment by‐passed the mats. At the seven sites where mats collected sediment, there was a considerable range in sediment deposition over the 18‐month sampling period with site‐average values (based on all mats at a site) ranging from 0.02 ± 0.06 to 1.15 ± 1.88 g cm−2; the average for all 136 mats was 0.41 ± 1.08 g cm−2, or approximately 0.27 g cm−2 year−1. Most of the sediment collected on the mats (n = 60) was sand‐sized (>63 μm) material. The site‐average total‐P content of the <63 μm fraction of the deposited sediment ranged between 616 and 1938 mg kg−1 (average 890 mg kg−1). About half of all the mats that collected sediment were from the front of the buffers. Comparison of the sediment in the buffer features with topsoil from the contributing upslope fields suggests that the buffers trap coarser sediment with lower P concentrations, than the contributing topsoil. This suggests that the finer fraction, enriched in total‐P, may be passing through the buffers towards river channels. Comparison between sites indicates that sediment deposition within buffers is greater at sites with steeper slopes, erodible soils and certain types of land use, such as maize for silage, reflecting the greater soil erosion and sediment transfers in these fields. The location and careful design of buffer features is a key factor in their effectiveness.
Agriculture as a source of phosphorus for eutrophication in southern Europe
Authors: Torrent J. , Barberis E. , Gil‐Sotres F.
Published: September 2007

Large areas of the southern European countries possess a Mediterranean climate, which influences soil properties, land use, fertilizer application practices and pathways of phosphorus (P) loss from agricultural soils. On average, inputs of fertilizer P exceed P exports from the agricultural areas in these countries; however, large differences in P surplus/deficit and soil P test values exist among regions. Losses of P in drainage water are modest except in some irrigated areas and in those regions where intensive animal production is concentrated. Losses of P in runoff water, whether as dissolved reactive or particulate P, can be substantial as a result of the significance of erosive processes under the land uses typical of the Mediterranean region, where extreme rainfall events contribute disproportionately to such losses. Eutrophication due sensu lato to agricultural P sources affects a relatively high proportion of rivers, lakes and reservoirs. The typical Mediterranean climate and patterns of land use result in marked seasonality in the concentration of P in surface waters. Despite the growing number of studies conducted, the contribution of agricultural P to eutrophication in southern European countries remains largely unassessed and thus warrants pertinent research at the soil, field and catchment scales.