Assessment of metal contamination in the biota of four rivers experiencing varying degrees of human impact.

Urbanization, agriculture, and other land transformations can affect water quality, decrease species biodiversity, and increase metal and nutrient concentrations in aquatic systems. Metal pollution, in particular, is a reported consequence of elevated anthropogenic inputs, especially from urbanized areas. The objectives of this study were to quantify metal (Cu, Al, Cd, Ni, and Pb) concentrations in the waters and biota of four streams in South Georgia, USA, and relate metal concentrations to land use and abiotic and biotic stream processes. Additionally, macrophytes, invertebrates, and fish were identified to assess biodiversity at each site. Metal concentrations in the three trophic levels differed among sites and species, correlating to differences in land use surrounding the rivers. The highest metal concentrations (except Al) were found in the streams most impacted by urbanization and development. Al concentrations were highest in streams surrounded by land dominated by forested areas. Metal content in macrophytes reflected metal concentrations in the water and was at least three orders of magnitude higher than any other trophic level. Despite metal concentration differences, all four streams contained similar water quality and were healthy based on macroinvertebrate community structure. This study provides insight into the impact of urbanization and the fate and effects of metals in river ecosystems with varying degrees of anthropogenic impact.

Responses of the sea anemone, Exaiptasia pallida, to ocean acidification conditions and zinc or nickel exposure.

Ocean acidification, caused by increasing atmospheric carbon dioxide (CO2), is a growing concern in marine environments. Land-based sources of pollution, such as metals, have also been a noted problem; however, little research has addressed the combined exposure of both pollutants to coral reef organisms. In this study we examined tissue metal accumulation and physiological effects (activity of anti-oxidant enzymes, catalase and glutathione reductase) in the sea anemone, Exaiptasia pallida after exposure to increased CO2, as well as zinc (Zn) or nickel (Ni). After exposure to four concentrations (nominal values=control, 10, 50, 100µg/L) of Zn or Ni over 7days, both metals accumulated in the tissues of E. pallida in a concentration-dependent manner. Anemones exposed to elevated CO2 (1000ppm) accumulated significant tissue burdens of Zn or Ni faster (by 48h) than those exposed to the same metal concentrations at ambient CO2. No differences were observed in catalase activity due to Zn exposure; however, 50µg/L Ni caused a significant increase in catalase activity at ambient CO2. No significant effect on catalase activity from CO2 exposure alone was observed. Glutathione reductase activity was affected by increased Zn or Ni exposure and those effects were influenced by increased CO2. Results of this study provide insight into the toxic mechanisms and environmental implications of CO2 and Zn or Ni exposure to the cnidarian E. pallida.

Targeted next generation sequencing approach identifies eighteen new candidate genes in normosmic hypogonadotropic hypogonadism and Kallmann syndrome.

The genetic basis is unknown for ∼60% of normosmic hypogonadotropic hypogonadism (nHH)/Kallmann syndrome (KS). DNAs from (17 male and 31 female) nHH/KS patients were analyzed by targeted next generation sequencing (NGS) of 261 genes involved in hypothalamic, pituitary, and/or olfactory pathways, or suggested by chromosome rearrangements. Selected variants were subjected to Sanger DNA sequencing, the gold standard. The frequency of Sanger-confirmed variants was determined using the ExAC database. Variants were classified as likely pathogenic (frameshift, nonsense, and splice site) or predicted pathogenic (nonsynonymous missense). Two novel FGFR1 mutations were identified, as were 18 new candidate genes including: AMN1, CCKBR, CRY1, CXCR4, FGF13, GAP43, GLI3, JAG1, NOS1, MASTL, NOTCH1, NRP2, PALM2, PDE3A, PLEKHA5, RD3, and TRAPPC9, and TSPAN11. Digenic and trigenic variants were found in 8/48 (16.7%) and 1/48 (2.1%) patients, respectively. NGS with confirmation by Sanger sequencing resulted in the identification of new causative FGFR1 gene mutations and suggested 18 new candidate genes in nHH/KS.