A sensitive genetic-based detection capability for Didymosphenia geminata

It is now well recognized that the increase in global transportation over the last two decades has brought with it an increased potential for the introduction of unwanted microorganisms (aquatic or terrestrial) that may have drastic effects on human and ecosystem health and agriculture. We have developed and validated a unique genetic fingerprinting tool for D. geminata. In concert, we developed field collection and preservation techniques specific for D. geminata along with genetic-based procedures that can now reliably detect D. geminate from a complex environmental community with a high degree of sensitivity. Recent work (Phase 2) has shown that the described methods will provide detection levels from <1 – 10,000 cells ml-1. We contend that the genetic based detection approaches used in this study offer great promise to meet the increasing demands to monitor the global threat from invasive micro-organisms

The Fecal Coliform/Fecal Streptococci Ratio (FC/FS) And Water Quality in the Bluegrass Region of Kentucky

In the mid 70\u27 s, someone noticed that the ratio of two indicator bacteria in fecal wastes - fecal coliforms (FC) and fecal streptococci (FS) - was characteristic of particular animal wastes. In human wastes, the fecal coliform/fecal streptococci ratio (FC/FS ratio) was greater than 4. In domesticated animals, like cattle, the ratio was between 0.1 and 4.0. In wild animals, the ratio was less than 0.1. Since that time, many attempts have been made to use the ratio to determine the source of fecal bacteria in contaminated ground water

Short-term Response of Soil Iron to Nitrate Addition

The inhibition of soil Fe(III) reduction by fertilizer NO3 − applications is complex and not completely understood. This inhibition is important to study because of the potential impact on soil physicochemical properties. We investigated the effect of adding NO3 − to a moderately well-drained agricultural soil (Sadler silt loam) under Fe(III)-reducing (anoxic) conditions. Stirred-batch experiments were conducted where NO3 − was added (0.05 and 1 mM) to anoxic slurries and changes in dissolved Fe(II) and Fe(III), oxalate-extractable Fe(II), and dissolved NO3 − were monitored as a function of time. Addition of 1 mM NO3 − inhibited Fe(II) production sharply with reaction time, from 10% after 1 h to 85% after 24 h. The duration of inhibition in Fe(II) production was closely related to the presence of available NO3 −, suggesting preferential use of NO3 − by nitrate reductase enzyme. Active nitrate reductase was confirmed by the fivefold decline in NO3 − reduction rates in the presence of tungstate (WO4 2−), a well-known inhibitor of nitrate reductase. In addition, NO3 −–dependent Fe(II) oxidation was observed to contribute to the inhibition in Fe(II) production. This finding was attributed to a combination of chemical reoxidation of Fe(II) by NO2 −– and NO3 −–dependent Fe(II) oxidation by autotrophic bacteria. These two processes became more important at a greater initial oxalate-Fe(II)/NO3 − concentration ratio. The inhibitory effects in Fe(II) production were short-term in the sense that once NO3 − was depleted, Fe(II) production resumed. These results underscore the complexity of the coupled N–Fe redox system in soils

Spectroscopic analyses of Fe and water in clays: A Martian surface weathering study

Martian surface morphology suggests the presence of liquid H2O on Mars in the past. Reflectance spectra of the Martian surface include features which correspond to the crystal field transitions of iron, as well as features supporting the presence of ice and minerals containing structural OH and surface water. Researchers initiated further spectroscopic studies of surface iron and water and structural OH in clays in order to determine what remotely obtained spectra can indicate about the presence of clays on Mars based on a clearer understanding of the factors influencing the spectral features. Current technology allows researchers to better correlate the low frequency fundamental stretching and bending vibrations of O-H bonds with the diagnostic near infrared overtone and combination bands used in mineral characterization and identification

Frequency of MUG Negative Escherichia coli in Kentucky Groundwater Samples

MUG negative Escherichia coli are a small fraction (2.5%) of the total E. coli in Kentucky groundwater samples. It is unlikely that they alone will cause a significant potential to underestimate fecal contamination using MUG as the primary criterion for that assessment. An unresolved question is how effectively MUG-based, defined-substrate tests address false negative water samples containing MUG positive E. coli

Agricultural Impacts on Fecal Contamination of Shallow Groundwaters in the Bluegrass Region of Kentucky

Any farming practices that degrade water quality contribute to agricultural nonpoint source pollution. This is a problem in Kentucky\u27s Bluegrass region where shallow soils and karst geology permit surface contaminants to reach groundwater quickly. Real and perceived threats to public health may make groundwater protection plans a reality if evidence for non-point source pollution in agricultural areas continues to grow

Montreal Protocol

DATE: Signed September 16, 1987; took effect January 1, 1989; amended 1990, 1992, 1995, 1997, and 1999 The Montreal Protocol was created to help preserve the Earth’s ozone layer by severely limiting the production and use of chlorofluorocarbons (CFCs ) and other halogenated compounds