Publications by authors named "E M Pilgrim"

19 Publications

  • Page 1 of 1

DNA methylation and expression of estrogen receptor alpha in fathead minnows exposed to 17α-ethynylestradiol.

Aquat Toxicol 2021 Apr 23;233:105788. Epub 2021 Feb 23.

US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, 45268, United States. Electronic address:

The gene expression response thought to underlie the negative apical effects resulting from estrogen exposure have been thoroughly described in fish. Although epigenetics are believed to play a critical role translating environmental exposures into the development of adverse apical effects, they remain poorly characterized in fish species. This study investigated alterations of DNA methylation of estrogen receptor alpha (esr1) in brain and liver tissues from 8 to 10 month old male fathead minnows (Pimephales promelas) after a 2d exposure to either 2.5 ng/L or 10 ng/L 17α-ethynylestradiol (EE2). Changes in the patterns of methylation were evaluated using targeted deep sequencing of bisulfite treated DNA in the 5' region of esr1. Methylation and gene expression were assessed at 2d of exposure and after a 7 and 14d depuration period. After 2d EE2 exposure, males exhibited significant demethylation in the 5' upstream region of esr1 in liver tissue, which was inversely correlated to gene expression. This methylation pattern reflected what was seen in females. No gene body methylation (GBM) was observed for liver of exposed males. Differential methylation was observed for a single upstream CpG site in the liver after the 14d depuration. A less pronounced methylation response was observed in the upstream region in brain tissue, however, several CpGs were necessarily excluded from the analysis. In contrast to the liver, a significant GBM response was observed across the entire gene body, which was sustained until at least 7d post-exposure. No differential expression was observed in the brain, limiting functional interpretation of methylation changes. The identification of EE2-dependent changes in methylation levels strongly suggests the importance of epigenetic mechanisms as a mediator of the organismal response to environmental exposures and the need for further characterization of the epigenome. Further, differential methylation following depuration indicates estrogenic effects persist well after the active exposure, which has implications for the risk posed by repeated exposures..
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http://dx.doi.org/10.1016/j.aquatox.2021.105788DOI Listing
April 2021

Metabarcoding quantifies differences in accumulation of ballast water borne biodiversity among three port systems in the United States.

Sci Total Environ 2020 Dec 3;749:141456. Epub 2020 Aug 3.

Smithsonian Environmental Research Center, Edgewater, MD 21037, USA.

Characterizing biodiversity conveyed in ships' ballast water (BW), a global driver of biological invasions, is critically important for understanding risks posed by this key vector and establishing baselines to evaluate changes associated with BW management. Here we employ high throughput sequence (HTS) metabarcoding of the 18S small subunit rRNA to test for and quantify differences in the accumulation of BW-borne biodiversity among three distinct recipient port systems in the United States. These systems were located on three different coasts (Pacific, Gulf, and Atlantic) and chosen to reflect distinct trade patterns and source port biogeography. Extensive sampling of BW tanks (n = 116) allowed detailed exploration of molecular diversity accumulation. Our results indicate that saturation of introduced zooplankton diversity may be achieved quickly, with fewer than 25 tanks needed to achieve 95% of the total extrapolated diversity, if source biogeography is relatively limited. However, as predicted, port systems with much broader source geographies require more extensive sampling to estimate diversity, which continues to accumulate after sampling >100 discharges. The ability to identify BW sources using molecular indicators was also found to depend on the breadth of source biogeography and the extent to which sources had been sampled. These findings have implications both for the effort required to fully understand introduced diversity and for projecting risks associated with future changes to maritime traffic that may increase source biogeography for many recipient ports. Our data also suggest that molecular diversity may not decline significantly with BW age, indicating either that some organisms survive longer than recognized in previous studies or that nucleic acids from dead organisms persist in BW tanks. We present evidence for detection of potentially invasive species in arriving BW but discuss important caveats that preclude strong inferences regarding the presence of living representatives of these species in BW tanks.
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http://dx.doi.org/10.1016/j.scitotenv.2020.141456DOI Listing
December 2020

DNA metabarcoding effectively quantifies diatom responses to nutrients in streams.

Ecol Appl 2020 12 18;30(8):e02205. Epub 2020 Aug 18.

Office of Research and Development, United States Environmental Protection Agency, Cincinnati, Ohio, 45268, USA.

Nutrient pollution from human activities remains a common problem facing stream ecosystems. Identifying ecological responses to phosphorus and nitrogen can inform decisions affecting the protection and management of streams and their watersheds. Diatoms are particularly useful because they are a highly diverse group of unicellular algae found in nearly all aquatic environments and are sensitive responders to increased nutrient concentrations. Here, we used DNA metabarcoding of stream diatoms as an approach to quantifying effects of total phosphorus (TP) and total nitrogen (TN). Threshold indicator taxa analysis (TITAN) identified operational taxonomic units (OTUs) that increased or decreased along TP and TN gradients along with nutrient concentrations at which assemblages had substantial changes in the occurrences and relative abundances of OTUs. Boosted regression trees showed that relative abundances of gene sequence reads for OTUs identified by TITAN as low P, high P, low N, or high N diatoms had strong relationships with nutrient concentrations, which provided support for potentially using these groups of diatoms as metrics in monitoring programs. Gradient forest analysis provided complementary information by characterizing multi-taxa assemblage change using multiple predictors and results from random forest models for each OTU. Collectively, these analyses showed that notable changes in diatom assemblage structure and OTUs began around 20 µg TP/L, low P diatoms decreased substantially and community change points occurred from 75 to 150 µg/L, and high P diatoms became increasingly dominant from 150 to 300 µg/L. Diatoms also responded to TN with large decreases in low N diatoms occurring from 280 to 525 µg TN/L and a transition to dominance by high N diatoms from 525-850 µg/L. These diatom responses to TP and TN could be used to inform protection efforts (i.e., anti-degradation) and management goals (i.e., nutrient reduction) in streams and watersheds. Our results add to the growing support for using diatom metabarcoding in monitoring programs.
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http://dx.doi.org/10.1002/eap.2205DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7731896PMC
December 2020

Dreissena veligers in western Lake Superior - inference from new low-density detection.

J Great Lakes Res 2019 ;45(3):691-699

Position at U.S. EPA through Oak Ridge Institute for Science and Education.

The notion that Lake Superior proper is inhospitable to dreissenid mussel survival has been challenged by recent finds on shipwrecks and rocky reefs in the Apostle Islands region. Motivated by concerns surrounding these finds, we conducted an intensive sampling campaign of Apostle Islands waters in 2017 to understand prevalence and distribution. The 100-site effort combined random and targeted sites and collected zooplankton, benthos, video, environmental DNA, and supporting water quality data. We did not find settled in any video footage or benthos samples, and quantitative PCR applied to eDNA samples was negative for veligers were found in almost half the zooplankton samples but at orders of magnitude lower densities than reported from other Laurentian Great Lakes. Veligers were most prevalent around the western islands and associated with shallower depths and slightly higher phosphorus and chlorophyll, but did not spatially match known (still very localized) settled colonies. This is the first study to conduct veliger-targeted sampling in western Lake Superior and the first to report consistent detection of veligers there. We speculate that these Apostle Islands veligers are not a new locally-spawned component of the zooplankton community, but instead are transported from an established population in the St. Louis River estuary (~100 km away) by longshore currents; i.e., low-density propagule pressure that may have been present for years. Small-mesh zooplankton data collected along a gradient from the Apostle Islands to the St. Louis River estuary and enumerated with thorough veliger searching would help elucidate these alternatives.
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http://dx.doi.org/10.1016/j.jglr.2019.03.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6662202PMC
January 2019

High-throughput environmental DNA analysis informs a biological assessment of an urban stream.

Ecol Indic 2019 ;104:378-389

United States Environmental Protection Agency, Office of Research and Development, 26 Martin Luther King Drive, Cincinnati, OH 45268, United States.

There is growing interest in the use of DNA barcoding and metabarcoding approaches to aid biological assessments and monitoring of waterbodies. While biodiversity measured by morphology and by DNA often has been found correlated, few studies have compared DNA data to established measures of impairment such as multimetric pollution tolerance indices used by many bioassessment programs. We incorporated environmental DNA (eDNA) metabarcoding of seston into a rigorous watershed-scale biological assessment of an urban stream to examine the extent to which eDNA richness and diversity patterns were correlated with multimetric indices and ecological impairment status designations. We also evaluated different filtering approaches and taxonomic classifications to identify best practices for environmental assessments. Seston eDNA revealed a wide diversity of eukaryotic taxa but was dominated by diatoms (36%). Differentiation among sites in alpha and beta diversity was greater when operational taxonomic units (OTUs) were classified taxonomically, but coarse resolution taxonomy (kingdom) was more informative than finer resolution taxonomy (family, genus). Correlations of DNA richness and diversity with multimetric indices for fish and macroinvertebrates were generally weak, possibly because Metazoa were not highly represented in our DNA dataset. Nonetheless, sites could be differentiated based on ecological impairment status, with more impaired sites having lower eDNA diversity as measured by the Shannon index, but higher taxonomic richness. Significant environmental drivers of community structure, as inferred from constrained ordination analyses, differed among kingdoms within the eDNA dataset, as well as from fish and macrobenthos, suggesting that eDNA provides novel environmental information. These results suggest that even a simple seston eDNA filtering protocol can provide biodiversity information of value to stream bioassessment programs. The approach bears further investigation as a potentially useful rapid assessment protocol to supplement more intensive field sampling efforts.
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http://dx.doi.org/10.1016/j.ecolind.2019.04.088DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6605098PMC
January 2019

Ballast Water Exchange and Invasion Risk Posed by Intracoastal Vessel Traffic: An Evaluation Using High Throughput Sequencing.

Environ Sci Technol 2018 09 21;52(17):9926-9936. Epub 2018 Aug 21.

Smithsonian Environmental Research Center , Edgewater , Maryland 21037 United States.

Ballast water remains a potent vector of non-native aquatic species introductions, despite increased global efforts to reduce risk of ballast water mediated invasions. This is particularly true of intracoastal vessel traffic, whose characteristics may limit the feasibility and efficacy of management through ballast water exchange (BWE). Here we utilize high throughput sequencing (HTS) to assess biological communities associated with ballast water being delivered to Valdez, Alaska from multiple source ports along the Pacific Coast of the United States. Our analyses indicate that BWE has a significant but modest effect on ballast water assemblages. Although overall richness was not reduced with exchange, we detected losses of some common benthic coastal taxa (e.g., decapods, mollusks, bryozoans, cnidaria) and gains of open ocean taxa (e.g., certain copepods, diatoms, and dinoflagellates), including some potentially toxic species. HTS-based metabarcoding identified significantly differentiated biodiversity signatures from individual source ports; this signal persisted, though weakened, in vessels undergoing BWE, indicating incomplete faunal turnover associated with management. Our analysis also enabled identification of taxa that may be of particular concern if established in Alaskan waters. While these results reveal a clear effect of BWE on diversity in intracoastal transit, they also indicate continued introduction risk of non-native and harmful taxa.
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http://dx.doi.org/10.1021/acs.est.8b02108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6944436PMC
September 2018

Spatial and temporal dynamics of a freshwater eukaryotic plankton community revealed via 18S rRNA gene metabarcoding.

Hydrobiologia 2018 ;818(1):71-86

US Environmental Protection Agency, Cincinnati, USA.

DNA metabarcoding is a sophisticated molecular tool that can enhance biological surveys of freshwater plankton communities by providing broader taxonomic coverage and, for certain groups, higher taxonomic resolution compared to morphological methods. We conducted 18S rRNA gene metabarcoding analyses on 214 water samples collected over a four-month period from multiple sites within a freshwater reservoir. We detected 1,314 unique operational taxonomic units that included various metazoans, protists, chlorophytes, and fungi. Alpha diversity differed among sites, suggesting local habitat variation linked to differing species responses. Strong temporal variation was detected at both daily and monthly scales. Diversity and relative abundance patterns for several protist groups (including dinoflagellates, ciliates, and cryptophytes) differed from arthropods (e.g., cladocerans and copepods), a traditional focus of plankton surveys. This suggests that the protists respond to different environmental dimensions and may therefore provide additional information regarding ecosystem status. Comparison of the sequence-based population survey data to conventional-based data revealed similar trends for taxa that were ranked among the most abundant in both approaches, although some groups were missing in each data set. These results highlight the potential benefit of supplementing conventional biological survey approaches with metabarcoding to obtain a more comprehensive understanding of freshwater plankton community structure and dynamics.
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http://dx.doi.org/10.1007/s10750-018-3593-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6781235PMC
January 2018

Early detection monitoring for aquatic non-indigenous species: Optimizing surveillance, incorporating advanced technologies, and identifying research needs.

J Environ Manage 2017 Nov 22;202(Pt 1):299-310. Epub 2017 Jul 22.

U.S. Environmental Protection Agency, Great Lakes National Program Office, Chicago, IL, 60604, USA. Electronic address:

Following decades of ecologic and economic impacts from a growing list of nonindigenous and invasive species, government and management entities are committing to systematic early- detection monitoring (EDM). This has reinvigorated investment in the science underpinning such monitoring, as well as the need to convey that science in practical terms to those tasked with EDM implementation. Using the context of nonindigenous species in the North American Great Lakes, this article summarizes the current scientific tools and knowledge - including limitations, research needs, and likely future developments - relevant to various aspects of planning and conducting comprehensive EDM. We begin with the scope of the effort, contrasting target-species with broad-spectrum monitoring, reviewing information to support prioritization based on species and locations, and exploring the challenge of moving beyond individual surveys towards a coordinated monitoring network. Next, we discuss survey design, including effort to expend and its allocation over space and time. A section on sample collection and analysis overviews the merits of collecting actual organisms versus shed DNA, reviews the capabilities and limitations of identification by morphology, DNA target markers, or DNA barcoding, and examines best practices for sample handling and data verification. We end with a section addressing the analysis of monitoring data, including methods to evaluate survey performance and characterize and communicate uncertainty. Although the body of science supporting EDM implementation is already substantial, research and information needs (many already actively being addressed) include: better data to support risk assessments that guide choice of taxa and locations to monitor; improved understanding of spatiotemporal scales for sample collection; further development of DNA target markers, reference barcodes, genomic workflows, and synergies between DNA-based and morphology-based taxonomy; and tools and information management systems for better evaluating and communicating survey outcomes and uncertainty.
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http://dx.doi.org/10.1016/j.jenvman.2017.07.045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5927374PMC
November 2017

Sensitivity and accuracy of high-throughput metabarcoding methods for early detection of invasive fish species.

Sci Rep 2017 04 13;7:46393. Epub 2017 Apr 13.

Systems Exposure Division, National Exposure Research Laboratory, Office of Research and Development, Environmental Protection Agency, Cincinnati, OH, 45268, United States of America.

High-throughput DNA metabarcoding has gained recognition as a potentially powerful tool for biomonitoring, including early detection of aquatic invasive species (AIS). DNA based techniques are advancing, but our understanding of the limits to detection for metabarcoding complex samples is inadequate. For detecting AIS at an early stage of invasion when the species is rare, accuracy at low detection limits is key. To evaluate the utility of metabarcoding in future fish community monitoring programs, we conducted several experiments to determine the sensitivity and accuracy of routine metabarcoding methods. Experimental mixes used larval fish tissue from multiple "common" species spiked with varying proportions of tissue from an additional "rare" species. Pyrosequencing of genetic marker, COI (cytochrome c oxidase subunit I) and subsequent sequence data analysis provided experimental evidence of low-level detection of the target "rare" species at biomass percentages as low as 0.02% of total sample biomass. Limits to detection varied interspecifically and were susceptible to amplification bias. Moreover, results showed some data processing methods can skew sequence-based biodiversity measurements from corresponding relative biomass abundances and increase false absences. We suggest caution in interpreting presence/absence and relative abundance in larval fish assemblages until metabarcoding methods are optimized for accuracy and precision.
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http://dx.doi.org/10.1038/srep46393DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5390320PMC
April 2017

Phylogenetic relationships of North American Gomphidae and their close relatives.

Syst Entomol 2017 Apr;42(2):347-358

Wautoma, WI, U.S.A.

Intrafamilial relationships among clubtail dragonflies (Gomphidae) have been the subject of many morphological studies, but have not yet been systematically evaluated using molecular data. Here we present the first molecular phylogeny of Gomphidae. We include six of the eight subfamilies previously suggested to be valid, and evaluate generic relationships within them. We have included examples of all genera reported from the Nearctic except . This sample includes all North American species of , which has allowed us to explore intrageneric relationships in that genus. Our particular focus is on the closest relatives of the genus , especially those North American species groups that have been commonly treated as subgenera of . The complex is split into additional genera, supported by molecular and morphological evidence: and are here considered to be valid genera. The genus , in our restricted sense, does not occur in the western hemisphere; in addition, is transferred to .
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http://dx.doi.org/10.1111/syen.12218DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6104399PMC
April 2017

A review of the impacts of degradation threats on soil properties in the UK.

Soil Use Manag 2015 Oct 12;31(Suppl Suppl 1):1-15. Epub 2015 Oct 12.

Department of Sustainable Soils and Grassland Systems Rothamsted Research Harpenden Hertfordshire AL5 2JQ UK.

National governments are becoming increasingly aware of the importance of their soil resources and are shaping strategies accordingly. Implicit in any such strategy is that degradation threats and their potential effect on important soil properties and functions are defined and understood. In this paper, we aimed to review the principal degradation threats on important soil properties in the UK, seeking quantitative data where possible. Soil erosion results in the removal of important topsoil and, with it, nutrients, C and porosity. A decline in soil organic matter principally affects soil biological and microbiological properties, but also impacts on soil physical properties because of the link with soil structure. Soil contamination affects soil chemical properties, affecting nutrient availability and degrading microbial properties, whilst soil compaction degrades the soil pore network. Soil sealing removes the link between the soil and most of the 'spheres', significantly affecting hydrological and microbial functions, and soils on re-developed brownfield sites are typically degraded in most soil properties. Having synthesized the literature on the impact on soil properties, we discuss potential subsequent impacts on the important soil functions, including food and fibre production, storage of water and C, support for biodiversity, and protection of cultural and archaeological heritage. Looking forward, we suggest a twin approach of field-based monitoring supported by controlled laboratory experimentation to improve our mechanistic understanding of soils. This would enable us to better predict future impacts of degradation processes, including climate change, on soil properties and functions so that we may manage soil resources sustainably.
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http://dx.doi.org/10.1111/sum.12212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5014291PMC
October 2015

Potential for DNA-based identification of Great Lakes fauna: match and mismatch between taxa inventories and DNA barcode libraries.

Sci Rep 2015 Jul 22;5:12162. Epub 2015 Jul 22.

U.S. Environmental Protection Agency, National Exposure Research Laboratory, Cincinnati Ohio, USA.

DNA-based identification of mixed-organism samples offers the potential to greatly reduce the need for resource-intensive morphological identification, which would be of value both to bioassessment and non-native species monitoring. The ability to assign species identities to DNA sequences found depends on the availability of comprehensive DNA reference libraries. Here, we compile inventories for aquatic metazoans extant in or threatening to invade the Laurentian Great Lakes and examine the availability of reference mitochondrial COI DNA sequences (barcodes) in the Barcode of Life Data System for them. We found barcode libraries largely complete for extant and threatening-to-invade vertebrates (100% of reptile, 99% of fish, and 92% of amphibian species had barcodes). In contrast, barcode libraries remain poorly developed for precisely those organisms where morphological identification is most challenging; 46% of extant invertebrates lacked reference barcodes with rates especially high among rotifers, oligochaetes, and mites. Lack of species-level identification for many aquatic invertebrates also is a barrier to matching DNA sequences with physical specimens. Attaining the potential for DNA-based identification of mixed-organism samples covering the breadth of aquatic fauna requires a concerted effort to build supporting barcode libraries and voucher collections.
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http://dx.doi.org/10.1038/srep12162DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510495PMC
July 2015

Evaluating ethanol-based sample preservation to facilitate use of DNA barcoding in routine freshwater biomonitoring programs using benthic macroinvertebrates.

PLoS One 2013 4;8(1):e51273. Epub 2013 Jan 4.

Southern California Coastal Water Research Project, Costa Mesa, CA, USA.

Molecular methods, such as DNA barcoding, have the potential to enhance biomonitoring programs worldwide. Altering routinely used sample preservation methods to protect DNA from degradation may pose a potential impediment to application of DNA barcoding and metagenomics for biomonitoring using benthic macroinvertebrates. Using higher volumes or concentrations of ethanol, requirements for shorter holding times, or the need to include additional filtering may increase cost and logistical constraints to existing biomonitoring programs. To address this issue we evaluated the efficacy of various ethanol-based sample preservation methods at maintaining DNA integrity. We evaluated a series of methods that were minimally modified from typical field protocols in order to identify an approach that can be readily incorporated into existing monitoring programs. Benthic macroinvertebrates were collected from a minimally disturbed stream in southern California, USA and subjected to one of six preservation treatments. Ten individuals from five taxa were selected from each treatment and processed to produce DNA barcodes from the mitochondrial gene cytochrome c oxidase I (COI). On average, we obtained successful COI sequences (i.e. either full or partial barcodes) for between 93-99% of all specimens across all six treatments. As long as samples were initially preserved in 95% ethanol, successful sequencing of COI barcodes was not affected by a low dilution ratio of 2∶1, transfer to 70% ethanol, presence of abundant organic matter, or holding times of up to six months. Barcoding success varied by taxa, with Leptohyphidae (Ephemeroptera) producing the lowest barcode success rate, most likely due to poor PCR primer efficiency. Differential barcoding success rates have the potential to introduce spurious results. However, routine preservation methods can largely be used without adverse effects on DNA integrity.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0051273PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3537618PMC
July 2013

Abiotic drivers and plant traits explain landscape-scale patterns in soil microbial communities.

Ecol Lett 2012 Nov 7;15(11):1230-1239. Epub 2012 Aug 7.

Soil and Ecosystem Ecology Laboratory, Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK.

The controls on aboveground community composition and diversity have been extensively studied, but our understanding of the drivers of belowground microbial communities is relatively lacking, despite their importance for ecosystem functioning. In this study, we fitted statistical models to explain landscape-scale variation in soil microbial community composition using data from 180 sites covering a broad range of grassland types, soil and climatic conditions in England. We found that variation in soil microbial communities was explained by abiotic factors like climate, pH and soil properties. Biotic factors, namely community-weighted means (CWM) of plant functional traits, also explained variation in soil microbial communities. In particular, more bacterial-dominated microbial communities were associated with exploitative plant traits versus fungal-dominated communities with resource-conservative traits, showing that plant functional traits and soil microbial communities are closely related at the landscape scale.
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http://dx.doi.org/10.1111/j.1461-0248.2012.01844.xDOI Listing
November 2012

Seasonal changes in children's physical activity: an examination of group changes, intra-individual variability and consistency in activity pattern across season.

Ann Hum Biol 2009 Jul-Aug;36(4):363-78. Epub 2009 May 9.

School of Sport and Health Sciences, University of Exeter, St Luke's Campus, Exeter, UK.

Background: Components of activity that are more variable over time may be more susceptible to manipulation in activity interventions.

Aim: The present study examined variability and consistency of components of children's activity across season.

Subjects And Methods: Sixty-four 9-11-year-old children wore an accelerometer for 6 days during winter and summer. Activity bouts (>or=4 s) greater than light (>or=LIGHT), moderate (>or=MOD) and vigorous (>or=VIG) intensity were recorded.

Results: Intra-individual variability of the activity components across season was greater for bout frequency (CV: >or=LIGHT = 6.6-9.9%, >or=MOD = 10.7-16.1%, >or=VIG = 17.0-26.8%) than bout intensity or duration (CV: >or=LIGHT = 3.4-7.4%, >or=MOD = 3.6-7.8%, >or=VIG = 4.2-10.0%, p<0.05) and for the frequency of >or=VIG bouts compared to the frequency of >or=LIGHT and >or=MOD bouts (p<0.05). All components of the activity pattern tended to track consistently when assessing >or=LIGHT and >or=MOD bouts (intra-class correlations (ICC) = 0.47-83, p<0.05), >or=VIG bouts in boys (ICC = 0.69-0.77, p<0.01) and frequency of >or=VIG bouts in girls (ICC = 0.82, p<0.01).

Conclusions: Bout frequency was the most variable component of activity across season. However, children tended to maintain their rank for bout frequency. It would be of interest to investigate whether bout frequency can be manipulated in an activity intervention.
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http://dx.doi.org/10.1080/03014460902824220DOI Listing
August 2009

Patterns of habitual activity across weekdays and weekend days in 9-11-year-old children.

Prev Med 2008 Apr 21;46(4):317-24. Epub 2007 Nov 21.

School of Sport and Health Sciences, University of Exeter, St. Luke's Campus, Heavitree, Exeter EX1 2LU, England, UK.

Objective: To characterize the pattern of activity in boys and girls across weekdays and weekend days.

Methods: Physical activity was recorded every 2 s by uniaxial accelerometry in 84 children, aged 9-11 years, for up to four weekdays and two weekend days. Activity bouts (>or= 4 s and >or= 5 min) greater than light (>or= LIGHT), moderate (>or= MOD) and vigorous (>or= VIG) intensity were recorded. The study took place in the South-West of England in 2007.

Results: The mean duration of activity bouts decreased as intensity increased from 11.0+/-1.3 s for >or= LIGHT activity to 6.1+/-1.0 s for >or= VIG activity. The frequency, duration and intensity of bouts were greater in boys than girls, and the frequency and duration of bouts were greater on weekdays than weekend days. Girls accumulated more activity sporadically than boys, whereas boys accumulated more activity in >or= 5-min bouts.

Conclusion: Sex differences and weekday/weekend differences in activity were largely due to the intensity of the most frequent bouts of activity and frequency of the most intense bouts. Information regarding the pattern of children's habitual activity can be used to inform activity interventions and assess the aspects of the activity pattern that are related to health.
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http://dx.doi.org/10.1016/j.ypmed.2007.11.004DOI Listing
April 2008

Combining DNA sequences and morphology in systematics: testing the validity of the dragonfly species Cordulegaster bilineata.

Heredity (Edinb) 2002 Sep;89(3):184-90

Department of Biological Sciences, Wright State University, Dayton, OH 45435, USA.

Morphological and molecular techniques are rarely combined when answering questions of taxonomic validity. In this study, we combine morphological techniques with DNA sequences to determine the validity of the dragonfly species Cordulegaster bilineata. The two dragonfly species C. bilineata and C. diastatops are very similar in size, body color, and morphological characters, and due to these similarities, the status of C. bilineata as a valid species is in question. In this study we compare morphological measurements of males and internal transcribed spacer 1 (ITS-1) sequences of rDNA between the two taxa. The hamule measurements (where copulation occurs) of males show little difference between the taxa in question, but the anal appendage measurements (where the male first contacts the female) show marked divergence between the two taxa. Cluster analysis with these anal appendage measurements correctly assigns almost all individuals measured into their respective taxon. PCR amplification products of ITS-1 display a approximately 50 bp size difference between C. bilineata (n = 4) and C. diastatops (n = 5) regardless of collection site. Sequence data for these amplifications show 51 bp missing in one locus in the ITS-1 of C. bilineatarelative to C. diastatops. A lone population of C. diastatops from Wisconsin has three individuals with ITS-1 products that match the size of both C. bilineata and C. diastatops. One individual from this population appears to yield two ITS-1 amplification products that match both C. bilineata and C. diastatops. Although this population may be evidence for hybridization between the two taxa, such hybridization is not necessarily sufficient to disqualify the validity of a separate species designation for C. bilineata. Morphology and ITS-1 sequences depict a high degree of divergence that is consistent with species-level differences.
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http://dx.doi.org/10.1038/sj.hdy.6800112DOI Listing
September 2002

Nosocomial Salmonella epidemic.

Arch Intern Med 1976 Sep;136(9):968-73

A patient admitted to the hospital with diarrhea due to Salmonella heidelberg subsequently developed fatal disseminated salmonellosis, despite vigorous antimicrobial treatment. Beginning five weeks after the initial patient's death, nine patients developed hospital-acquired S heidelberg infections characterized by diarrhea (in seven) and bacteremia (in two). A careful search for salmonellosis among patients and hospital staff revealed two asymptomatic excretors. Extensive culturing of samples from the environment did not show any contaminated objects or reservoirs. The epidemic ended after initiation of an energetic handwashing campaign and isolation procedures. The strain of S heidelberg isolated was resistant to chloramphenicol, ampicillin, and gentamicin. Especially interesting in the epidemic were the prolonged time between death of the index case and the appearance of nosocomial cases, the high fatality rate, and the marked antibiotic resistance.
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September 1976

Oiled seabirds in the west.

Authors:
E G Pilgrim

Vet Rec 1967 Jul;81(1):24-5

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http://dx.doi.org/10.1136/vr.81.1.24DOI Listing
July 1967