The Diatom Flora of Phosphorus-Enriched And Unenriched Sites in an Everglades Marsh

Diatoms are used as environmental indicators in the Florida Everglades, a large subtropical wetland highly impacted by phosphorus pollution. However, the taxonomy of the diatom flora, a mix of temperate and tropical diatoms, is understudied. Therefore, we analyzed the taxonomy of 71 diatom taxa collected in Water Conservation Area 2A (WCA-2A). Diatoms were analyzed from sediment cores and from floating algal mats collected in phosphorus-enriched northern WCA-2A and in relatively unenriched southern WCA-2A. In addition, diatoms were analyzed from experimental mesocosms in southern WCA- 2A dosed with 0-126 µgL-1 P-PO4. Total phosphorus optima were calculated for dominant taxa. Average percent abundances in phosphorus-enriched and unenriched conditions are given for all taxa. Eleven taxa were dominant (\u3e5% abundance in at least one sample) in unenriched conditions, 17 taxa were observed only in phosphorus-enriched conditions, and 9 taxa were observed only below 2 cm in sediment cores. We compared the flora to taxonomical accounts of diatoms from temperate and tropical regions, with a special focus on nearby Antillean islands (Cuba, Jamaica, and Puerto Rico). Light microscope images of each taxon and SEM images of selected taxa are presented. Taxonomical measurements are given for each taxon, and differences from descriptions in other taxonomical accounts are discussed. A new combination, Achnanthes caledonica Lange-Bertalot = Achnanthidium caledonicum (Lange-Bertalot) comb nov. is proposed

Impact of Pre-Columbian Agriculture, Climate Change, and Tectonic Activity Inferred From a 5,700-Year Paleolimnological Record from Lake Nicaragua

Lake Nicaragua, the largest lake in Central America, is a promising site for paleolimnological study of past climate change, tectonic and volcanic activity, and pre-Columbian agriculture in the region. It is near the northern limit of the Intertropical Convergence Zone (ITCZ), which brings the rainy season to the tropics, so effects of decreasing precipitation due to southern migration of the ITCZ through the Holocene should be observable. Because fault zones and an active volcano lie within the lake, the long-term impact of tectonic and volcanic activity can also be examined. Finally, the fertile volcanic soils near the lake may have encouraged early agriculture. We analyzed diatoms, biogenic silica (BSi), total organic carbon (TOC), water content, volcanic glass, and magnetic susceptibility in a sediment core from Lake Nicaragua with eleven accelerator mass spectroscopy radiocarbon dates, spanning ~5,700 years. Sediment accumulation rates decreased from the bottom to the top of the core, indicating a general drying trend through the Holocene. An increase in eutrophic diatom abundance suggests that pre-Columbian agriculture impacted the lake as early as ~5,400 cal yr BP. Above a horizon of coarser grains deposited sometime between ~5,200 and 1,600 cal yr BP, planktonic diatoms increased and remained dominant to the top of the core, indicating that water depth permanently increased. Although magnetic susceptibility peaked and water content dipped at the coarse horizon, volcanic glass fragments did not increase, suggesting that the coarse horizon and subsequent increase in water depth were caused by tectonic rather than by volcanic activity. Decreased accumulation rates of BSi and TOC indicate that water became clearer when depth increased

Epithelial-Mesenchymal Transition (EMT) Gene Variants and Epithelial Ovarian Cancer (EOC) Risk

Epithelial-mesenchymal transition (EMT) is a process whereby epithelial cells assume mesenchymal characteristics to facilitate cancer metastasis. However, EMT also contributes to the initiation and development of primary tumors. Prior studies that explored the hypothesis that EMT gene variants contribute to epithelial ovarian carcinoma (EOC) risk have been based on small sample sizes and none have sought replication in an independent population. We screened 15,816 single-nucleotide polymorphisms (SNPs) in 296 genes in a discovery phase using data from a genome-wide association study of EOC among women of European ancestry (1,947 cases and 2,009 controls) and identified 793 variants in 278 EMT-related genes that were nominally (P < 0.05) associated with invasive EOC. These SNPs were then genotyped in a larger study of 14,525 invasive-cancer patients and 23,447 controls. A P-value <0.05 and a false discovery rate (FDR) <0.2 were considered statistically significant. In the larger dataset, GPC6/GPC5 rs17702471 was associated with the endometrioid subtype among Caucasians (odds ratio (OR) = 1.16, 95% CI = 1.07-1.25, P = 0.0003, FDR = 0.19), whereas F8 rs7053448 (OR = 1.69, 95% CI = 1.27-2.24, P = 0.0003, FDR = 0.12), F8 rs7058826 (OR = 1.69, 95% CI = 1.27-2.24, P = 0.0003, FDR = 0.12), and CAPN13 rs1983383 (OR = 0.79, 95% CI = 0.69-0.90, P = 0.0005, FDR = 0.12) were associated with combined invasive EOC among Asians. In silico functional analyses revealed that GPC6/GPC5 rs17702471 coincided with DNA regulatory elements. These results suggest that EMT gene variants do not appear to play a significant role in the susceptibility to EOC.Other Research Uni

Appendix A. A table of 14C dates from Chatsworth Bog and Nelson Lake.

A table of 14C dates from Chatsworth Bog and Nelson Lake

A genome-wide association study identifies a new ovarian cancer susceptibility locus on 9p22.2

Epithelial ovarian cancer has a major heritable component, but the known susceptibility genes explain less than half the excess familial risk1. We performed a genome wide association study (GWAS) to identify common ovarian cancer susceptibility alleles. We evaluated 507,094 SNPs genotyped in 1,817 cases and 2,353 controls from the UK and ~2 million imputed SNPs. We genotyped the 22,790 top ranked SNPs in 4,274 cases and 4,809 controls of European ancestry from Europe, USA and Australia. We identified 12 SNPs at 9p22 associated with disease risk (P<10−8). The most significant SNP (rs3814113; P = 2.5 × 10−17) was genotyped in a further 2,670 ovarian cancer cases and 4,668 controls confirming its association (combined data odds ratio = 0.82 95% CI 0.79 – 0.86, P-trend = 5.1 × 10−19). The association differs by histological subtype, being strongest for serous ovarian cancers (OR 0.77 95% CI 0.73 – 0.81, Ptrend = 4.1 × 10−21)