Mercury biomagnification through food webs is affected by physical and chemical characteristics of lakes.

Mercury (Hg) contamination in aquatic systems remains a global concern because the organic form, methyl Hg (MeHg), can biomagnify to harmful concentrations in fish, fish-eating wildlife, and humans. Food web transfer of MeHg has been explored using models of log MeHg versus relative trophic position (nitrogen isotopes, δ(15)N), but regression slopes vary across systems for unknown reasons. In this study, MeHg biomagnification was determined for 11 lake food webs in Kejimkujik National Park, Nova Scotia, Canada, and compared to physical and chemical lake characteristics using principal component and multiple regression analyses.

Haplotype structure and positive selection at TLR1.

Toll-like receptor 1, when dimerized with Toll-like receptor 2, is a cell surface receptor that, upon recognition of bacterial lipoproteins, activates the innate immune system. Variants in TLR1 associate with the risk of a variety of medical conditions and diseases, including sepsis, leprosy, tuberculosis, and others. The foremost of these is rs5743618 c.

Science and policy on endocrine disrupters must not be mixed: a reply to a "common sense" intervention by toxicology journal editors.

The "common sense" intervention by toxicology journal editors regarding proposed European Union endocrine disrupter regulations ignores scientific evidence and well-established principles of chemical risk assessment. In this commentary, endocrine disrupter experts express their concerns about a recently published, and is in our considered opinion inaccurate and factually incorrect, editorial that has appeared in several journals in toxicology. Some of the shortcomings of the editorial are discussed in detail.

The effect of thinning and clear-cut on changes in the relative abundance of root-feeding beetle (Coleoptera: Curculionidae) in Pinus taeda plantations in central Alabama and Georgia.

Background: Root-feeding beetles, particularly Hylastes spp., Hylobius pales Herbst and Pachylobius picivorus Germar, increase in abundance in stressed forest stands and vector Grosmannia and Leptographium spp. fungi, which contribute to southern pine decline (SPD) in the southeastern United States.

Inference of human continental origin and admixture proportions using a highly discriminative ancestry informative 41-SNP panel.

Background: Accurate determination of genetic ancestry is of high interest for many areas such as biomedical research, personal genomics and forensics. It remains an important topic in genetic association studies, as it has been shown that population stratification, if not appropriately considered, can lead to false-positive and -negative results. While large association studies typically extract ancestry information from available genome-wide SNP genotypes, many important clinical data sets on rare phenotypes and historical collections assembled before the GWAS area are in need of a feasible method (i.

Reproductive health of yellow perch (Perca flavescens) from a biological mercury hotspot in Nova Scotia, Canada.

Methylmercury (MeHg) exposure is known to adversely affect the reproductive health of laboratory fish, but its impacts on the sexual development of wild fishes are not well studied. Kejimkujik National Park and National Historic Site (KNPNHS) region of Nova Scotia, Canada, has been identified as a biological mercury (Hg) hotspot. To determine whether Hg was adversely affecting the reproductive health of wild yellow perch (Perca flavescens), sexually mature male and female perch were collected from 12 lakes within KNPNHS (mean muscle total Hg: 0.

Worldwide population variation and haplotype analysis at the serotonin transporter gene SLC6A4 and implications for association studies.

Background: Variation at the serotonin transporter gene, SLC6A4, has been associated with a variety of neuropsychiatric disorders and could be involved in other health-related phenotypes.

Methods: To determine the extent of variation at SLC6A4, we genotyped 23 markers on approximately 2500 individuals from 47 global populations, including the promoter variable number tandem repeat (VNTR) and 2 single nucleotide polymorphisms (SNPs) immediately flanking its variable region (rs25531 and rs25532), the intron 2 VNTR, and 19 additional SNPs.

Results: We observed several rare alleles at the promoter VNTR (some novel) and population-specific distributions of the reported functional SNPs rs25531, rs25532, and rs6355, as well as two alleles at the intron 2 VNTR.

Food web analysis reveals effects of pH on mercury bioaccumulation at multiple trophic levels in streams.

Biomagnification processes and the factors that govern them, including those for mercury (Hg), are poorly understood in streams. Total and methyl Hg concentrations and relative trophic position (using δ(15)N) were analyzed in biofilm and invertebrates from 21 streams in New Brunswick, Canada to assess food web biomagnification leading to the common minnow blacknose dace (Rhinichthys atratulus), a species known to have Hg concentrations that are higher in low pH waters. Biomagnification slopes within stream food webs measured using Hg vs.

Evidence of impaired health in yellow perch (Perca flavescens) from a biological mercury hotspot in northeastern North America.

Few studies have investigated the effects of mercury (Hg) on wild fish from remote areas, even though these fish can have high total Hg concentrations. In Kejimkujik National Park and National Historic Site (KNPNHS), Nova Scotia, Canada, concentrations of total Hg in many yellow perch (Perca flavescens) currently exceed the estimated threshold level for adverse effects in fish (0.2 µg Hg g(-1) (wet wt), whole body).

Biotic interactions in temporal trends (1992-2010) of organochlorine contaminants in the aquatic food web of Lake Laberge, Yukon Territory.

Declines in 6 organochlorine (OC) contaminant groups; chlordane (CHL), DDT, HCH, toxaphene (CHB), PCB and chlorinated benzenes (CBz) were measured in biota of a sub-Arctic lake (Lake Laberge, YT) following the closure of a commercial fishery in 1991. This study examined morphological (length, weight, age), biochemical (lipid content, δ(13)C, δ(15)N), population and OC data for 9 fishes and zooplankton between 1993 and 2003 (2010 for lake trout) to investigate causes for the OC declines. Growth dilution was a major factor influencing the decrease of OCs in lake trout, round whitefish and possibly zooplankton most notably in the early 2000s.

High diversity and no significant selection signal of human ADH1B gene in Tibet.

Background: ADH1B is one of the most studied human genes with many polymorphic sites. One of the single nucleotide polymorphism (SNP), rs1229984, coding for the Arg48His substitution, have been associated with many serious diseases including alcoholism and cancers of the digestive system. The derived allele, ADH1B*48His, reaches high frequency only in East Asia and Southwest Asia, and is highly associated with agriculture.

First all-in-one diagnostic tool for DNA intelligence: genome-wide inference of biogeographic ancestry, appearance, relatedness, and sex with the Identitas v1 Forensic Chip.

When a forensic DNA sample cannot be associated directly with a previously genotyped reference sample by standard short tandem repeat profiling, the investigation required for identifying perpetrators, victims, or missing persons can be both costly and time consuming. Here, we describe the outcome of a collaborative study using the Identitas Version 1 (v1) Forensic Chip, the first commercially available all-in-one tool dedicated to the concept of developing intelligence leads based on DNA. The chip allows parallel interrogation of 201,173 genome-wide autosomal, X-chromosomal, Y-chromosomal, and mitochondrial single nucleotide polymorphisms for inference of biogeographic ancestry, appearance, relatedness, and sex.

Exploring genomic structure differences and similarities between the Greek and European HapMap populations: implications for association studies.

Studies of the genomic structure of the Greek population and Southeastern Europe are limited, despite the central position of the area as a gateway for human migrations into Europe. HapMap has provided a unique tool for the analysis of human genetic variation. Europe is represented by the CEU (Northwestern Europe) and the TSI populations (Tuscan Italians from Southern Europe), which serve as reference for the design of genetic association studies.

Increased mercury and body size and changes in trophic structure of Gambusia puncticulata (Poeciliidae) along the Almendares River, Cuba.

The Almendares River is the largest river draining the area around Havana City, Cuba. The watershed is heavily populated and industrialized, which has had a significant impact on the flow and water quality of the river. The main goal of this study was to analyze the spatial variability in dietary habits, nutrient flow (using stable isotope ratios δ(15)N and δ(13)C), and mercury (Hg) levels along the Almendares River upstream and downstream of point-source discharges using localized fish Gambusia puncticulata.

Biomagnification of mercury through lake trout (Salvelinus namaycush) food webs of lakes with different physical, chemical and biological characteristics.

Mercury (Hg) biomagnification in aquatic ecosystems remains a concern because this pollutant is known to affect the health of fish-eating wildlife and humans, and the fish themselves. The "rate" of mercury biomagnification is being assessed more frequently using stable nitrogen isotope ratios (δ(15)N), a measure of relative trophic position of biota within a food web. Within food webs and across diverse systems, log-transformed Hg concentrations are significantly and positively related to δ(15)N and the slopes of these models vary from one study to another for reasons that are not yet understood.

Introducing the Forensic Research/Reference on Genetics knowledge base, FROG-kb.

Background: Online tools and databases based on multi-allelic short tandem repeat polymorphisms (STRPs) are actively used in forensic teaching, research, and investigations. The Fst value of each CODIS marker tends to be low across the populations of the world and most populations typically have all the common STRP alleles present diminishing the ability of these systems to discriminate ethnicity. Recently, considerable research is being conducted on single nucleotide polymorphisms (SNPs) to be considered for human identification and description.

How do aquatic communities respond to contaminants? It depends on the ecological context.

Context dependency refers to variation in ecological patterns and processes across environmental or spatiotemporal gradients. Research on context dependency in basic ecology has focused primarily on variation in the relative importance of species interactions (e.g.

Genome-wide association study of Tourette's syndrome.

Tourette's syndrome (TS) is a developmental disorder that has one of the highest familial recurrence rates among neuropsychiatric diseases with complex inheritance. However, the identification of definitive TS susceptibility genes remains elusive. Here, we report the first genome-wide association study (GWAS) of TS in 1285 cases and 4964 ancestry-matched controls of European ancestry, including two European-derived population isolates, Ashkenazi Jews from North America and Israel and French Canadians from Quebec, Canada.

Exome sequencing identifies recurrent somatic RAC1 mutations in melanoma.

We characterized the mutational landscape of melanoma, the form of skin cancer with the highest mortality rate, by sequencing the exomes of 147 melanomas. Sun-exposed melanomas had markedly more ultraviolet (UV)-like C>T somatic mutations compared to sun-shielded acral, mucosal and uveal melanomas. Among the newly identified cancer genes was PPP6C, encoding a serine/threonine phosphatase, which harbored mutations that clustered in the active site in 12% of sun-exposed melanomas, exclusively in tumors with mutations in BRAF or NRAS.

Reconstructing Native American population history.

The peopling of the Americas has been the subject of extensive genetic, archaeological and linguistic research; however, central questions remain unresolved. One contentious issue is whether the settlement occurred by means of a single migration or multiple streams of migration from Siberia. The pattern of dispersals within the Americas is also poorly understood.

Structural diversity and African origin of the 17q21.31 inversion polymorphism.

The 17q21.31 inversion polymorphism exists either as direct (H1) or inverted (H2) haplotypes with differential predispositions to disease and selection. We investigated its genetic diversity in 2,700 individuals, with an emphasis on African populations.

CDP-diacylglycerol synthetase-controlled phosphoinositide availability limits VEGFA signaling and vascular morphogenesis.

Understanding the mechanisms that regulate angiogenesis and translating these into effective therapies are of enormous scientific and clinical interests. In this report, we demonstrate the central role of CDP-diacylglycerol synthetase (CDS) in the regulation of VEGFA signaling and angiogenesis. CDS activity maintains phosphoinositide 4,5 bisphosphate (PIP2) availability through resynthesis of phosphoinositides, whereas VEGFA, mainly through phospholipase Cγ1, consumes PIP2 for signal transduction.

Aquatic and terrestrial organic matter in the diet of stream consumers: implications for mercury bioaccumulation.

The relative contribution of aquatic vs. terrestrial organic matter to the diet of consumers in fluvial environments and its effects on bioaccumulation of contaminants such as mercury (Hg) remain poorly understood. We used stable isotopes of carbon and nitrogen in a gradient approach (consumer isotope ratio vs.

ApoB-containing lipoproteins regulate angiogenesis by modulating expression of VEGF receptor 1.

Despite the clear major contribution of hyperlipidemia to the prevalence of cardiovascular disease in the developed world, the direct effects of lipoproteins on endothelial cells have remained obscure and are under debate. Here we report a previously uncharacterized mechanism of vessel growth modulation by lipoprotein availability. Using a genetic screen for vascular defects in zebrafish, we initially identified a mutation, stalactite (stl), in the gene encoding microsomal triglyceride transfer protein (mtp), which is involved in the biosynthesis of apolipoprotein B (ApoB)-containing lipoproteins.