52 research outputs found

    Hepatitis B Virus X Protein Drives Multiple Cross-Talk Cascade Loops Involving NF-κB, 5-LOX, OPN and Capn4 to Promote Cell Migration

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    Hepatitis B virus X protein (HBx) plays an important role in the development of hepatocellular carcinoma (HCC). However, the mechanism remains unclear. Recently, we have reported that HBx promotes hepatoma cell migration through the upregulation of calpain small subunit 1 (Capn4). In addition, several reports have revealed that osteopontin (OPN) plays important roles in tumor cell migration. In this study, we investigated the signaling pathways involving the promotion of cell migration mediated by HBx. We report that HBx stimulates several factors in a network manner to promote hepatoma cell migration. We showed that HBx was able to upregulate the expression of osteopontin (OPN) through 5-lipoxygenase (5-LOX) in HepG2-X/H7402-X (stable HBx-transfected cells) cells. Furthermore, we identified that HBx could increase the expression of 5-LOX through nuclear factor-κB (NF-κB). We also found that OPN could upregulate Capn4 through NF-κB. Interestingly, we showed that Capn4 was able to upregulate OPN through NF-κB in a positive feedback manner, suggesting that the OPN and Capn4 proteins involving cell migration affect each other in a network through NF-κB. Importantly, NF-κB plays a crucial role in the regulation of 5-LOX, OPN and Capn4. Thus, we conclude that HBx drives multiple cross-talk cascade loops involving NF-κB, 5-LOX, OPN and Capn4 to promote cell migration. This finding provides new insight into the mechanism involving the promotion of cell migration by HBx

    Do Regulations to Protect Endangered Species on Private Lands Affect Local Employment? Evidence from the Listing of the Lesser Prairie Chicken

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    The U.S. Endangered Species Act is often criticized as “pitting people against wildlife" by conserving habitat at the cost of jobs, but relatively little is known about the labor market effects of listing a species under the Endangered Species Act. We examine changes in employment associated with the lesser prairie chicken, which was listed as threatened in May 2014. Using county-level employment data and variation in suitable prairie chicken habitat, we apply a difference-in-differences strategy to measure the employment effects of the listing decision. We find evidence that employment declined about 1.5% in affected counties. The effect is proportional to habitat, which means counties with relatively more habitat experienced a larger share of employment losses

    The effect of endangered species regulations on local employment: Evidence from the listing of the lesser prairie chicken

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    The U.S. Endangered Species Act is often criticized as pitting people against species by conserving habitat at the cost of jobs. Critics of current conservation policies argue that the protection of species is stripping landowners of their property rights and putting people in industries tied to resource extraction out of jobs. While changes in employment are important measures of the public costs of endangered species protection, relatively little is known about the labor market impacts of listing a species under the Endangered Species Act. We examine changes in employment associated with the lesser prairie chicken, an imperiled bird that was listed as threatened in May 2014. Using monthly county-level employment data and variation in potential prairie chicken habitat, we apply a difference-in-differences strategy to measure the employment impacts of the listing decision. We find evidence that employment declined after the listing by about 1% in counties with habitat relative to non-habitat areas. We also find that the impact is proportional to habitat, so counties with the most prairie-chicken habitat experienced the largest impacts on employment

    Use of transgenic GFP reporter strains of the nematode Caenorhabditis elegans to investigate the patterns of stress responses induced by pesticides and by organic extracts from agricultural soils

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    As a free-living nematode, C. elegans is exposed to various pesticides used in agriculture, as well as to persistent organic residues which may contaminate the soil for long periods. Following on from our previous study of metal effects on 24 GFP-reporter strains representing four different stress-response pathways in C. elegans (Anbalagan et al. 2012), we now present parallel data on the responses of these same strains to several commonly used pesticides. Some of these, like dichlorvos, induced multiple stress genes in a concentration-dependent manner. Unusually, endosulfan induced only one gene (cyp-34A9) to very high levels (8-10-fold) even at the lowest test concentration, with a clear plateau at higher doses. Other pesticides, like diuron, did not alter reporter gene expression detectably even at the highest test concentration attainable, while others (such as glyphosate) did so only at very high concentrations. We have also used five responsive GFP reporters to investigate the toxicity of soil pore water from two agricultural sites in south-east Spain, designated P74 (used for cauliflower production, but significantly metal contaminated) and P73 (used for growing lettuce, but with only background levels of metals). Both soil pore water samples induced all five test genes to varying extents, yet artificial mixtures containing all major metals present had essentially no effect on these same transgenes. Soluble organic contaminants present in the pore water were extracted with acetone and dichloromethane, then after evaporation of the solvents, the organic residues were redissolved in ultrapure water to reconstitute the soluble organic components of the original soil pore water. These organic extracts induced transgene expression at similar or higher levels than the original pore water. Addition of the corresponding metal mixtures had either no effect, or reduced transgene expression towards the levels seen with soil pore water only. We conclude that the main toxicants present in these soil pore water samples are organic rather than metallic in nature. Organic extracts from a control standard soil (Lufa 2.2) had negligible effects on expression of these genes, and similarly several pesticides had little effect on the expression of a constitutive myo-3::GFP transgene. Both the P73 and P74 sites have been treated regularly with (undisclosed) pesticides, as permitted under EU regulations, though other (e.g. industrial) organic residues may also be present
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