Dissociation of DNA damage and mitochondrial injury caused by hydrogen peroxide in SV-40 transformed lung epithelial cells

Background: Since lung epithelial cells are constantly being exposed to reactive oxygen intermediates (ROIs), the alveolar surface is a major site of oxidative stress, and each cell type may respond differently to oxidative stress. We compared the extent of oxidative DNA damage with that of mitochondrial injury in lung epithelial cells at the single cell level. Result: DNA damage and mitochondrial injury were measured after oxidative stress in the SV-40 transformed lung epithelial cell line challenged with hydrogen peroxide (H2O2). Single cell analysis of DNA damage was determined by assessing the number of 8-oxo-2-deoxyguanosine (8-oxo-dG) positive cells, a marker of DNA modification, and the length of a comet tail. Mitochondrial membrane potential, ΔΨm, was determined using JC-1. A 1 h pulse of H2O2 induced small amounts of apoptosis (3%). 8-oxo-dG-positive cells and the length of the comet tail increased within 1 h of exposure to H2O2. The number of cells with reduced ΔΨm increased after the addition of H2O2 in a concentration-dependent manner. In spite of a continual loss of ΔΨm, DNA fragmentation was reduced 2 h after exposure to H2O2. Conclusion: The data suggest that SV-40 transformed lung epithelial cells are resistant to oxidative stress, showing that DNA damage can be dissociated from mitochondrial injury. © 2002 Fujii et al; licensee BioMed Central Ltd

Temporal trends of sulfur levels in soils of northwest Ohio

Sulfur (S) is an essential nutrient for plant growth. Despite increasing reports of yield responses of crops to S fertilization, there is limited information about changes in the soil test concentrations of S. This study used a soil chemical analysis dataset from 2002 to 2014 to evaluate changes in soil S and other nutrient levels. The soil‐test database comprised 8,428 topsoil samples (0–20 cm depth layer) collected from 143 farm fields located in the northwest (NW) Ohio counties of Defiance, Paulding, and Williams. Except for S, the database showed no significant changes in soil chemical properties from NW Ohio between 2002 and 2014. Soil sulfate (SO42−) levels have linearly decreased by 63% from 2002 to 2014, reaching the range of concentration considered deficient for the main cereal crops. With no changes in soil organic matter (SOM) and pH, this result was attributed primarily to enactment of air quality regulations, since soil SO42− decreases were directly correlated with the reductions of SO2 emissions (−70%), SO42− in rainwater (−66%) and deposited (−52%) in NW Ohio between the years of 2002–2013. Furthermore, combined increasing crop yields and insufficient compensation by fertilization had role on decreasing soil SO42− levels. Current fertilization practices and wet deposition of S have not been sufficient to balance S removals from soil leading to the declines in the soil test S levels. It is imperative to paid more attention to practices that maintain soil S fertility levels to avoid yield penalties associated with soil S deficiencies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/166181/1/ldr3745.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/166181/2/ldr3745_am.pd