The Distribution of Road Salt in Private Drinking Water Wells in a Southeastern New York Suburban Township.

We used a GIS analysis of sodium and chloride concentrations in private water wells in a southeastern New York township to describe the pattern of distribution of road salt in aquifers tapped for drinking water. The primary source of road salt was sodium chloride, and sodium and chloride concentrations were significantly correlated ( = 0.80, < 0.01). Chloride concentrations in wells increased as the percentage of impervious surface cover (ISC) within a 250-m radius around wells increased ( = 0.87, < 0.01) and declined with increasing distance to the nearest road ( = 0.76, < 0.01). Wells that were located lower in elevation than the nearest road had higher concentrations of chloride than wells that were higher than the nearest road, but this occurred only when the nearest road was >30 m from the wells ( < 0.01). Chloride concentrations were not affected by well depth or adjacent road type (major or minor roads). Surface geology and hydrologic soil class had significant effects ( < 0.01) on chloride concentrations in wells, with porous surface geology types and well-drained soils having higher concentrations; these effects may be confounded by the fact that ISC was more likely to occur on these permeable surface geology and soil types. Hot and cold spot analysis revealed substantial unevenness in chloride concentrations. Results for sodium were similar to those for chloride. Overall, these results indicate that road salt contamination of groundwater is unevenly distributed and is affected by landscape factors that can be used to guide well testing and best management practices of deicing salt distribution.

Trends in atmospheric ammonium concentrations in relation to atmospheric sulfate and local agriculture.

Ammonium (NH(4)(+)) concentrations in air and precipitation at the Institute of Ecosystem Studies (IES) in southeastern New York, USA declined over an 11-year period from 1988 to 1999, but increased from 1999 to 2001. These trends in particulate NH(4)(+) correlated well with trends in particulate SO(4)(2-) over the 1988-2001 period. The NH(4)(+) trends were not as well correlated with local cattle and milk production, which declined continuously throughout the period. This suggests that regional transport of SO(4)(2-) may have a greater impact on concentrations of NH(4)(+) and subsequent deposition than local agricultural emissions of NH(3). Ammonium concentrations in precipitation correlated significantly with precipitation SO(4)(2-) concentrations for the 1984-2001 period although NH(4)(+) in precipitation increased after 1999 and SO(4)(2-) in precipitation continued to decline after 1999. The correlation between NH(4)(+) and SO(4)(2-) was stronger for particulates than for precipitation. Particulate NH(4)(+) concentrations were also correlated with particulate SO(4)(2-) concentrations at 31 of 35 eastern U.S. CASTNet sites that had at least 10 years of data. Air concentrations of NH(4)(+) and SO(4)(2-) were more strongly correlated at the sites that were located within an agricultural landscape than in forested sites. At most of the sites there was either no trend or a decrease in NH(4)(+) dry deposition during the 1988-2001 period. The sites that showed an increasing trend in NH(4)(+) dry deposition were generally located in the southeastern U.S. The results of this study suggest that, in the northeastern U.S., air concentrations of NH(4)(+) and subsequent deposition may be more closely linked to SO(4)(2-) and thus SO(2) emissions than with NH(3) emissions. These results also suggest that reductions in S emissions have reduced NH(4)(+) transport to and NH(4)(+)-N deposition in the Northeast.

Donor verification using Short Tandem Repeat (STR) analysis directly from blood collected in PAXgene RNA tubes.

Biorepository processing includes nucleic acid extractions in batch mode from a large number of blood samples from many different donors. Handling such a large number of biospecimens presents the challenge of ensuring that samples are not switched or mislabeled during processing. One approach for confirming donor identity from DNA samples is the use of multiplexed fluorescent PCR for detecting Short Tandem Repeat (STR) allelic-size polymorphisms for a set of common autosomal loci. While donor identity of DNA extracted directly from blood collected in standard tubes containing anticoagulants can be easily verified by generating STR profiles, RNA from blood collected in PAXgene Blood RNA tubes (PAXgene RNA tubes) is depleted of DNA and is not amenable to STR fingerprinting for donor identity verification. We investigated the feasibility of isolating DNA directly from blood collected in PAXgene RNA tubes for use as template for STR DNA fingerprinting for blood donor identity verification. We determined that DNA extraction can be performed manually with the QIAamp DNA Blood Minikit or on the QIAxtractor instrument with minimal pre-processing protocol additions, and that DNA isolated from blood collected in PAXgene RNA tubes is of sufficient quantity and quality for successful STR fingerprint analysis. Adaptation of quality assurance methods such as the PAXgene RNA tube DNA extraction/STR fingerprinting assay described here is a good practice that ensures that biobanking collections provide scientists with high quality, donor-verified biomaterial.

LRH-1 and Nanog regulate Dax1 transcription in mouse embryonic stem cells.

Dax1, an atypical orphan nuclear receptor expressed in steroidogenic tissues, has recently been shown to be expressed in mouse embryonic stem (mES) cells and is required for pluripotency. While the mechanisms of transcriptional regulation of Dax1 in steroidogenic organs have been well characterized, those in mES cells have not. Here we report that 500 bp of the Dax1 gene promoter sequence are sufficient to drive expression in mES cells. In steroidogenic tissues, NR5A1 (Sf1) binds to nuclear receptor binding sites within this sequence to regulate Dax1 expression. In mES cells, while NR5A1 (Sf1) is not expressed, NR5A2 (LRH-1) expression is robust. Luciferase assays, EMSA and overexpression/knockdown studies demonstrate that LRH-1 binds the -128 site and regulates Dax1 in mES cells. Predicated on recent work indicating that Nanog binds to the Dax1 intron, we have used chromatin immunoprecipitation experiments (ChIP) to define an intronic site that is bound by Nanog. Overexpression and knockdown of Nanog in mES cells result in alteration of Dax1 expression, and luciferase assays reveal that this sequence can enhance transcription of a Dax1 reporter construct. These data indicate that LRH-1 and Nanog cooperate to regulate Dax1 expression in mES cells.

Emerging indirect and long-term road salt effects on ecosystems.

Widespread use of salts as deicing agents on roads has been perceived as a significant source of environmental and economic damage. Early studies focused on near-road and short-term effects where concentrations can exceed several grams per liter. Evidence is accumulating that the use of salts has significant effects over broader areas, longer time frames, and is affecting a range of ecological processes. Concentrations of NaCl can be elevated throughout an ecosystem to >100 mg Cl(-) /L, which may have nonlethal and possibly subtle effects on sensitive life stages of several organisms. NaCl seems subject to retention within terrestrial and aquatic ecosystems, thus prolonging the actual duration of exposure and leading to elevated warm-season concentrations when reproduction may be occurring or other sensitive life stages are present. Many of the alternatives to NaCl reduce some of these negative effects, although are currently cost prohibitive for large-scale use. Some techniques for managing application rates are improvements in technology, while others involve novel mixtures of organic compounds that may have new environmental consequences. The increasing evidence of these widespread and persistent environmental consequences must be brought into decisions on deicing procedures.

Dax1 up-regulates Oct4 expression in mouse embryonic stem cells via LRH-1 and SRA.

Dax1 (Nr0b1) is an atypical orphan nuclear receptor that has recently been shown to play a role in mouse embryonic stem (mES) cell pluripotency. Here we describe a mechanism by which Dax1 maintains pluripotency. In steroidogenic cells, Dax1 protein interacts with the NR5A nuclear receptor steroidogenic factor 1 (Nr5a1) to inhibit transcription of target genes. In mES cells, liver receptor homolog 1 (LRH-1, Nr5a2), the other NR5A family member, is expressed, and LRH-1 has been shown to interact with Dax1. We demonstrate by coimmunoprecipitation that Dax1 is, indeed, able to form a complex with LRH-1 in mES cells. Because Dax1 was historically characterized as an inhibitor of steroidogenic factor 1-mediated transcriptional activation, we hypothesized that Dax1 would inhibit LRH-1 action in mES cells. Therefore, we examined the effect of Dax1 on the LRH-1-mediated activation of the critical ES cell factor Oct4 (Pou5f1). Chromatin immunoprecipitation localized Dax1 to the Oct4 promoter at the LRH-1 binding site, and luciferase assays together with Dax1 overexpression and knockdown experiments revealed that, rather than repress, Dax1 accentuated LRH-1-mediated activation of the Oct4 gene. Similar to our previously published studies that defined the RNA coactivator steroid receptor RNA activator as the critical mediator of Dax1 coactivation function, Dax1 augmentation of LRH-1-mediated Oct4 activation is dependent upon steroid receptor RNA activator. Finally, utilizing published chromatin immunoprecipitation data of whole-genome binding sites of LRH-1 and Dax1, we show that LRH-1 and Dax1 commonly colocalize at 288 genes (43% of LRH-1 target genes), many of which are involved in mES cell pluripotency. Thus, our results indicate that Dax1 plays an important role in the maintenance of pluripotency in mES cells through interaction with LRH-1 and transcriptional activation of Oct4 and other genes.

Effect of climate change between 1984 and 2007 on precipitation chemistry at a site in northeastern U.S.A.

Climate change predictions for the northeastern US call for an increase in tropical storms and a decrease in extra tropical cyclones including continental storms. We ran 24-h back trajectories for each precipitation event that occurred at the Cary Institute of Ecosystem Studies in southeastern New York, U.S.A. from 1984 to 2007 and analyzed precipitation chemistry as well as air mass position 24 h prior to the onset of each precipitation event. The results showed an increase in marine precipitation and a slight but statistically insignificant decrease in continental precipitation during the 1984-2007 period. The chemistry of precipitation from the two directions was quite different marine storms were higher in Na4 and Cl- but lower in solutes associated with acid precipitation (H+, SO4(2-), NO3-, and NH4+). Annual mean concentrations of acid precipitation solutes declined for storms from both directions during the period. We used a simple mixing model based on the current rates of increase and decrease of marine and continental precipitation respectively to show that chemical changes in precipitation resulting from the shift in storm tracks are small compared to chemical changes due to emissions reductions.

In search of adrenocortical stem and progenitor cells.

Scientists have long hypothesized the existence of tissue-specific (somatic) stem cells and have searched for their location in different organs. The theory that adrenocortical organ homeostasis is maintained by undifferentiated stem or progenitor cells can be traced back nearly a century. Similar to other organ systems, it is widely believed that these rare cells of the adrenal cortex remain relatively undifferentiated and quiescent until needed to replenish the organ, at which time they undergo proliferation and terminal differentiation. Historical studies examining cell cycle activation by label retention assays and regenerative potential by organ transplantation experiments suggested that the adrenocortical progenitors reside in the outer periphery of the adrenal gland. Over the past decade, the Hammer laboratory, building on this hypothesis and these observations, has endeavored to understand the mechanisms of adrenocortical development and organ maintenance. In this review, we summarize the current knowledge of adrenal organogenesis. We present evidence for the existence and location of adrenocortical stem/progenitor cells and their potential contribution to adrenocortical carcinomas. Data described herein come primarily from studies conducted in the Hammer laboratory with incorporation of important related studies from other investigators. Together, the work provides a framework for the emerging somatic stem cell field as it relates to the adrenal gland.

Long-term sodium chloride retention in a rural watershed: legacy effects of road salt on streamwater concentration.

Sodium and chloride concentrations and export increased from 1986 to 2005 in a rural stream in southeastern New York. Concentrations increased 1.5 mg/L per year (chloride) and 0.9 mg/L per year (sodium), and export increased 33,000 kg/year (chloride) and 20,000 kg/year (sodium) during this period. We estimate that salt used for deicing accounted for 91% of the sodium chloride input to the watershed, while sewage and water softeners accounted for less than 10% of the input. Road salt use in the watershed did not increase during the study, but sodium and chloride from sewage and water softeners is likely to have increased slightly due to a small increase in population. Increased input from sewage and water softeners cannot account for the increase in concentration and export from the watershed. Model results suggest that the increase in streamwater concentration and export was likely due to a lag effect of long-term road salt use and subsurface buildup.

Increased salinization of fresh water in the northeastern United States.

Chloride concentrations are increasing at a rate that threatens the availability of fresh water in the northeastern United States. Increases in roadways and deicer use are now salinizing fresh waters, degrading habitat for aquatic organisms, and impacting large supplies of drinking water for humans throughout the region. We observed chloride concentrations of up to 25% of the concentration of seawater in streams of Maryland, New York, and New Hampshire during winters, and chloride concentrations remaining up to 100 times greater than unimpacted forest streams during summers. Mean annual chloride concentration increased as a function of impervious surface and exceeded tolerance for freshwater life in suburban and urban watersheds. Our analysis shows that if salinity were to continue to increase at its present rate due to changes in impervious surface coverage and current management practices, many surface waters in the northeastern United States would not be potable for human consumption and would become toxic to freshwater life within the next century.