A late quaternary pollen record from Cedarburg Bog, Wisconsin

Late Quaternary (from the last glaciation to present) forest history is inferred from the Cedarburg Bog fossil pollen record. Analysis of fossil pollen samples extend over 4 meters of continuous core recovered from near the center of the bog. The deepest and oldest of the fossil pollen assemblages (ca. 12,000 years ago) suggest open spruce woodlands unlike any in the contemporary boreal ecosystem. Pollen from the Pleistocene-Holocene transition (11,000 years ago) is marked by a number of abrupt changes in forest composition related to rapid climate change, species immigration, and progressive soils and ecosystem maturation. By 9,000 years ago most of the modern forest plant species were established. These mixed deciduous forests persisted until the historical deforestation

History of Inuit Community Exposure to Lead, Cadmium, and Mercury in Sewage Lake Sediments

Exposure to lead, cadmium, and mercury is known to be high in many arctic Inuit communities. These metals are emitted from industrial and urban sources, are distributed by long-range atmospheric transport to remote regions, and are found in Inuit country foods. Current community exposure to these metals can be measured in food, but feces and urine are also excellent indicators of total exposure from ingestion and inhalation because a high percentage of each metal is excreted. Bulk domestic sewage or its residue in a waste treatment system is a good substitute measure. Domestic waste treatment systems that accumulate metals in sediment provide an accurate historical record of changes in ingestion or inhalation. We collected sediment cores from an arctic lake used for facultative domestic sewage treatment to identify the history of community exposure to Pb, Cd, and Hg. Cores were dated and fluxes were measured for each metal. A nearby lake was sampled to measure combined background and atmospheric inputs, which were subtracted from sewage lake data. Pb, Cd, and Hg inputs from sewage grew rapidly after the onset of waste disposal in the late 1960s and exceeded the rate of population growth in the contributing community from 1970 to 1990. The daily per-person Pb input in 1990 (720,000 ng/person per day) exceeded the tolerable daily intake level. The Cd input (48,000 ng/person per day) and Hg input (19,000 ng/person per day) were below the respective TDI levels at the time

Aged G Protein-Coupled Receptor Kinase 3 (Grk3)-Deficient Mice Exhibit Enhanced Osteoclastogenesis and Develop Bone Lesions Analogous to Human Paget’s Disease of Bone

Paget’s Disease of Bone (PDB) is a metabolic bone disease that is characterized by dysregulated osteoclast function leading to focal abnormalities of bone remodeling. It can lead to pain, fracture, and bone deformity. G protein-coupled receptor kinase 3 (GRK3) is an important negative regulator of G protein-coupled receptor (GPCR) signaling. GRK3 is known to regulate GPCR function in osteoblasts and preosteoblasts, but its regulatory function in osteoclasts is not well defined. Here, we report that Grk3 expression increases during osteoclast differentiation in both human and mouse primary cells and established cell lines. We also show that aged mice deficient in Grk3 develop bone lesions similar to those seen in human PDB and other Paget’s Disease mouse models. We show that a deficiency in Grk3 expression enhances osteoclastogenesis in vitro and proliferation of hematopoietic osteoclast precursors in vivo but does not affect the osteoclast-mediated bone resorption function or cellular senescence pathway. Notably, we also observe decreased Grk3 expression in peripheral blood mononuclear cells of patients with PDB compared with age- and gender-matched healthy controls. Our data suggest that GRK3 has relevance to the regulation of osteoclast differentiation and that it may have relevance to the pathogenesis of PDB and other metabolic bone diseases associated with osteoclast activation

A late quaternary pollen record from Cedarburg Bog, Wisconsin

Late Quaternary (from the last glaciation to present) forest history is inferred from the Cedarburg Bog fossil pollen record. Analysis of fossil pollen samples extend over 4 meters of continuous core recovered from near the center of the bog. The deepest and oldest of the fossil pollen assemblages (ca. 12,000 years ago) suggest open spruce woodlands unlike any in the contemporary boreal ecosystem. Pollen from the Pleistocene-Holocene transition (11,000 years ago) is marked by a number of abrupt changes in forest composition related to rapid climate change, species immigration, and progressive soils and ecosystem maturation. By 9,000 years ago most of the modern forest plant species were established. These mixed deciduous forests persisted until the historical deforestation

Mutations of γ-aminobutyric acid and glycine receptors change alcohol cutoff: Evidence for an alcohol receptor?

Alcohols in the homologous series of n -alcohols increase in central nervous system depressant potency with increasing chain length until a “cutoff” is reached, after which further increases in molecular size no longer increase alcohol potency. A similar phenomenon has been observed in the regulation of ligand-gated ion channels by alcohols. Different ligand-gated ion channels exhibit radically different cutoff points, suggesting the existence of discrete alcohol binding pockets of variable size on these membrane proteins. The identification of amino acid residues that determine the alcohol cutoff may, therefore, provide information about the location of alcohol binding sites. Alcohol regulation of the glycine receptor is critically dependent on specific amino acid residues in transmembrane domains 2 and 3 of the α subunit. We now demonstrate that these residues in the glycine α1 and the γ-aminobutyric acid ρ1 receptors also control alcohol cutoff. By mutation of Ser-267 to Gln, it was possible to decrease the cutoff in the glycine α1 receptor, whereas mutation of Ile-307 and/or Trp-328 in the γ-aminobutyric acid ρ1 receptor to smaller residues increased the cutoff. These results support the existence of alcohol binding pockets in these membrane proteins and suggest that the amino acid residues present at these positions can control the size of the alcohol binding cavity. </jats:p