Reproductive effects in two species of native freshwater gastropod mollusc exposed to 17β-oestradiol or an environmentally relevant mixture of oestrogenic chemicals in outdoor mesocosms

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Recent evidence suggests that molluscs may be sensitive to the effects of endocrine disrupting chemicals (EDCs) in a similar manner to vertebrates, such as fish. Despite this (with the exception of TBT-induced imposex in marine gastropods), molluscs have been largely overlooked in the field of endocrine disruption. Life-cycle studies were conducted in which two species of native UK freshwater gastropod molluscs (the hermaphrodite Planorbarius corneus and the gonochorist Viviparus viviparus) were exposed to either 17β-oestradiol or environmentally relevant mixtures of chemicals known to be oestrogenic to vertebrates and to be present in UK treated sewage effluents (TSE) and rivers. Adult snails were exposed for four months in outdoor mesocosms, fed by river water, over the spring and summer (breeding season) in order to examine effects on reproductive output, growth and mortality. Furthermore, offspring (F1s) were also developmentally exposed over the same period. F1 juvenile snails were then depurated in river water for nine months (over winter) after which time their growth, survival, and reproductive success were measured in further un-dosed river water mesocosm studies in the following spring/summer. Histopathology was used to determine immediate effects of chemical exposure on adult and F1 snails’ reproductive health. Histopathology was also used to determine long lasting effects of chemical exposure on depurated F1s. Exposure to oestrogenic chemicals resulted in a range of effects, including modulated fecundity and growth in F0 adults, to retardation of growth, sexual development and fecundity in developmentally exposed F1s. Exposure to mixtures of oestrogenic chemicals also resulted in possible modulation of the immune system, resulting in increased parasitism and over winter mortality of exposed F1s compared to snails exposed to river water alone. Differences in sensitivity and response to exposure between the two species and the generations were also observed

Reproductive effects in two species of native freshwater gastropod mollusc exposed to 17β-oestradiol or an environmentally relevant mixture of oestrogenic chemicals in outdoor mesocosms

Recent evidence suggests that molluscs may be sensitive to the effects of endocrine disrupting chemicals (EDCs) in a similar manner to vertebrates, such as fish. Despite this (with the exception of TBT-induced imposex in marine gastropods), molluscs have been largely overlooked in the field of endocrine disruption. Life-cycle studies were conducted in which two species of native UK freshwater gastropod molluscs (the hermaphrodite Planorbarius corneus and the gonochorist Viviparus viviparus) were exposed to either 17β-oestradiol or environmentally relevant mixtures of chemicals known to be oestrogenic to vertebrates and to be present in UK treated sewage effluents (TSE) and rivers. Adult snails were exposed for four months in outdoor mesocosms, fed by river water, over the spring and summer (breeding season) in order to examine effects on reproductive output, growth and mortality. Furthermore, offspring (F1s) were also developmentally exposed over the same period. F1 juvenile snails were then depurated in river water for nine months (over winter) after which time their growth, survival, and reproductive success were measured in further un-dosed river water mesocosm studies in the following spring/summer. Histopathology was used to determine immediate effects of chemical exposure on adult and F1 snails’ reproductive health. Histopathology was also used to determine long lasting effects of chemical exposure on depurated F1s. Exposure to oestrogenic chemicals resulted in a range of effects, including modulated fecundity and growth in F0 adults, to retardation of growth, sexual development and fecundity in developmentally exposed F1s. Exposure to mixtures of oestrogenic chemicals also resulted in possible modulation of the immune system, resulting in increased parasitism and over winter mortality of exposed F1s compared to snails exposed to river water alone. Differences in sensitivity and response to exposure between the two species and the generations were also observed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Reproductive effects in two species of native freshwater gastropod mollusc exposed to 17β-oestradiol or an environmentally relevant mixture of oestrogenic chemicals in outdoor mesocosms

Recent evidence suggests that molluscs may be sensitive to the effects of endocrine disrupting chemicals (EDCs) in a similar manner to vertebrates, such as fish. Despite this (with the exception of TBT-induced imposex in marine gastropods), molluscs have been largely overlooked in the field of endocrine disruption. Life-cycle studies were conducted in which two species of native UK freshwater gastropod molluscs (the hermaphrodite Planorbarius corneus and the gonochorist Viviparus viviparus) were exposed to either 17β-oestradiol or environmentally relevant mixtures of chemicals known to be oestrogenic to vertebrates and to be present in UK treated sewage effluents (TSE) and rivers. Adult snails were exposed for four months in outdoor mesocosms, fed by river water, over the spring and summer (breeding season) in order to examine effects on reproductive output, growth and mortality. Furthermore, offspring (F1s) were also developmentally exposed over the same period. F1 juvenile snails were then depurated in river water for nine months (over winter) after which time their growth, survival, and reproductive success were measured in further un-dosed river water mesocosm studies in the following spring/summer. Histopathology was used to determine immediate effects of chemical exposure on adult and F1 snails’ reproductive health. Histopathology was also used to determine long lasting effects of chemical exposure on depurated F1s. Exposure to oestrogenic chemicals resulted in a range of effects, including modulated fecundity and growth in F0 adults, to retardation of growth, sexual development and fecundity in developmentally exposed F1s. Exposure to mixtures of oestrogenic chemicals also resulted in possible modulation of the immune system, resulting in increased parasitism and over winter mortality of exposed F1s compared to snails exposed to river water alone. Differences in sensitivity and response to exposure between the two species and the generations were also observed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Genome-wide association analysis of more than 120,000 individuals identifies 15 new susceptibility loci for breast cancer.

Genome-wide association studies (GWAS) and large-scale replication studies have identified common variants in 79 loci associated with breast cancer, explaining ∼14% of the familial risk of the disease. To identify new susceptibility loci, we performed a meta-analysis of 11 GWAS, comprising 15,748 breast cancer cases and 18,084 controls together with 46,785 cases and 42,892 controls from 41 studies genotyped on a 211,155-marker custom array (iCOGS). Analyses were restricted to women of European ancestry. We generated genotypes for more than 11 million SNPs by imputation using the 1000 Genomes Project reference panel, and we identified 15 new loci associated with breast cancer at P < 5 × 10(-8). Combining association analysis with ChIP-seq chromatin binding data in mammary cell lines and ChIA-PET chromatin interaction data from ENCODE, we identified likely target genes in two regions: SETBP1 at 18q12.3 and RNF115 and PDZK1 at 1q21.1. One association appears to be driven by an amino acid substitution encoded in EXO1.BCAC is funded by Cancer Research UK (C1287/A10118, C1287/A12014) and by the European Community's Seventh Framework Programme under grant agreement 223175 (HEALTH-F2-2009-223175) (COGS). Meetings of the BCAC have been funded by the European Union COST programme (BM0606). Genotyping on the iCOGS array was funded by the European Union (HEALTH-F2-2009-223175), Cancer Research UK (C1287/A10710, C8197/A16565), the Canadian Institutes of Health Research (CIHR) for the CIHR Team in Familial Risks of Breast Cancer program and the Ministry of Economic Development, Innovation and Export Trade of Quebec, grant PSR-SIIRI-701. Combination of the GWAS data was supported in part by the US National Institutes of Health (NIH) Cancer Post-Cancer GWAS initiative, grant 1 U19 CA148065-01 (DRIVE, part of the GAME-ON initiative). For a full description of funding and acknowledgments, see the Supplementary Note.This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/ng.324

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Association of ESR1 gene tagging SNPs with breast cancer risk

We have conducted a three-stage, comprehensive single nucleotide polymorphism (SNP)-tagging association study of ESR1 gene variants (SNPs) in more than 55 000 breast cancer cases and controls from studies within the Breast Cancer Association Consortium (BCAC). No large risks or highly significant associations were revealed. SNP rs3020314, tagging a region of ESR1 intron 4, is associated with an increase in breast cancer susceptibility with a dominant mode of action in European populations. Carriers of the c-allele have an odds ratio (OR) of 1.05 [95% Confidence Intervals (CI) 1.02–1.09] relative to t-allele homozygotes, P = 0.004. There is significant heterogeneity between studies, P = 0.002. The increased risk appears largely confined to oestrogen receptor-positive tumour risk. The region tagged by SNP rs3020314 contains sequence that is more highly conserved across mammalian species than the rest of intron 4, and it may subtly alter the ratio of two mRNA splice forms

Association of ESR1 gene tagging SNPs with breast cancer risk.

We have conducted a three-stage, comprehensive single nucleotide polymorphism (SNP)-tagging association study of ESR1 gene variants (SNPs) in more than 55,000 breast cancer cases and controls from studies within the Breast Cancer Association Consortium (BCAC). No large risks or highly significant associations were revealed. SNP rs3020314, tagging a region of ESR1 intron 4, is associated with an increase in breast cancer susceptibility with a dominant mode of action in European populations. Carriers of the c-allele have an odds ratio (OR) of 1.05 [95% Confidence Intervals (CI) 1.02-1.09] relative to t-allele homozygotes, P = 0.004. There is significant heterogeneity between studies, P = 0.002. The increased risk appears largely confined to oestrogen receptor-positive tumour risk. The region tagged by SNP rs3020314 contains sequence that is more highly conserved across mammalian species than the rest of intron 4, and it may subtly alter the ratio of two mRNA splice forms

A common coding variant in CASP8 is associated with breast cancer risk

The Breast Cancer Association Consortium (BCAC) has been established to conduct combined case-control analyses with augmented statistical power to try to confirm putative genetic associations with breast cancer. We genotyped nine SNPs for which there was some prior evidence of an association with breast cancer: CASP8 D302H (rs1045485), IGFBP3 -202 C --> A (rs2854744), SOD2 V16A (rs1799725), TGFB1 L10P (rs1982073), ATM S49C (rs1800054), ADH1B 3' UTR A --> G (rs1042026), CDKN1A S31R (rs1801270), ICAM5 V301I (rs1056538) and NUMA1 A794G (rs3750913). We included data from 9-15 studies, comprising 11,391-18,290 cases and 14,753-22,670 controls. We found evidence of an association with breast cancer for CASP8 D302H (with odds ratios (OR) of 0.89 (95% confidence interval (c.i.): 0.85-0.94) and 0.74 (95% c.i.: 0.62-0.87) for heterozygotes and rare homozygotes, respectively, compared with common homozygotes; P(trend) = 1.1 x 10(-7)) and weaker evidence for TGFB1 L10P (OR = 1.07 (95% c.i.: 1.02-1.13) and 1.16 (95% c.i.: 1.08-1.25), respectively; P(trend) = 2.8 x 10(-5)). These results demonstrate that common breast cancer susceptibility alleles with small effects on risk can be identified, given sufficiently powerful studies

Five polymorphisms and breast cancer risk: results from the Breast Cancer Association Consortium.

Previous studies have suggested that minor alleles for ERCC4 rs744154, TNF rs361525, CASP10 rs13010627, PGR rs1042838, and BID rs8190315 may influence breast cancer risk, but the evidence is inconclusive due to their small sample size. These polymorphisms were genotyped in more than 30,000 breast cancer cases and 30,000 controls, primarily of European descent, from 30 studies in the Breast Cancer Association Consortium. We calculated odds ratios (OR) and 95% confidence intervals (95% CI) as a measure of association. We found that the minor alleles for these polymorphisms were not related to invasive breast cancer risk overall in women of European descent: ECCR4 per-allele OR (95% CI) = 0.99 (0.97-1.02), minor allele frequency = 27.5%; TNF 1.00 (0.95-1.06), 5.0%; CASP10 1.02 (0.98-1.07), 6.5%; PGR 1.02 (0.99-1.06), 15.3%; and BID 0.98 (0.86-1.12), 1.7%. However, we observed significant between-study heterogeneity for associations with risk for single-nucleotide polymorphisms (SNP) in CASP10, PGR, and BID. Estimates were imprecise for women of Asian and African descent due to small numbers and lower minor allele frequencies (with the exception of BID SNP). The ORs for each copy of the minor allele were not significantly different by estrogen or progesterone receptor status, nor were any significant interactions found between the polymorphisms and age or family history of breast cancer. In conclusion, our data provide persuasive evidence against an overall association between invasive breast cancer risk and ERCC4 rs744154, TNF rs361525, CASP10 rs13010627, PGR rs1042838, and BID rs8190315 genotypes among women of European descent