Encouraging Revegetation in Australia with a Groundwater Recharge Credit Scheme

This paper describes a comprehensive method to design, test and then implement a Payments for Ecosystem Services (PES) framework to combat the environmental consequences of extensive native vegetation clearance in Australia. Clearing of vegetation, primarily due to the expansion of farming areas, has often resulted in regional dryland and irrigation salinity. The market based approach adopted ? a groundwater recharge credit trading scheme ? was designed using empirical data from a social survey and experimental economics. The objective of the trial is to test the cost effectiveness of an incentive based recharge credit trade scheme designed to engage landholders in establishing and managing deep rooted pasture and woody perennials to reduce these adverse salinity impacts. The scheme, based on a voluntary ?cap and trade? approach, allows farmers to meet recharge obligations by land management actions or by trading credits. Assessment of the scheme so far suggests that an incentive for aggregate group outcome achievement included in the design may have motivated higher enrollment rates than would have otherwise resulted. A schedule has been developed relating land management practices and recharge credits. The audited performance based payment system, has provided increased motivation to manage for environmental outcomes compared to the previous policy.Payments for Ecosystem Services (PES), market based instrument, cap and trade, salinity credit, revegetation, experimental economics

Measuring price elasticities of demand and supply of water entitlements based on stated and revealed preference data

Estimates of price elasticities of water entitlements, known as permanent water or water rights in the United States, are complicated by data limitations and problems of endogeneity. To overcome these issues, we develop an approach to generate stated preference data and combine them with revealed preference data to estimate price elasticities from various types of water entitlement sales in the southern Murray-Darling Basin, Australia. Our results suggest that price elasticities of demand and supply of high security water entitlements are inelastic in the relevant market price range between AUD $1,700 to$2,100 per mega-liter, and that supply is relatively more inelastic than demand. For lower reliability water entitlements, the price elasticity of demand is estimated to be even more inelastic than high security water entitlements. The price elasticity of supply for general security water entitlements is similar to high security water entitlements, while the supply of low reliability water entitlements is extremely inelastic for our data set. The comparison between the stated and revealed preference data provides strong evidence of support for a data fusion approach, nevertheless, some differences in water sale preferences were found for irrigators choosing not to sell all of their water. The consistency of our results signals support for the use of this methodology in other water basins around the world.Alec Zuo, Sarah Ann Wheeler, W.L. (Vic) Adamowicz, Peter C. Boxall and Darla Hatton-MacDonal

The value of Antarctic and Southern Ocean ecosystem services

Antarctica and the Southern Ocean provide numerous ecosystem services that benefit people globally, but many are ‘invisible’ to markets and to some decision makers. A subset of these services — Antarctic tourism, commercial fisheries, and a suite of inter-related regulating services — are conservatively valued at ~US $180 billion annually, highlighting their importance

Heterozygosity for Pten Promotes Tumorigenesis in a Mouse Model of Medulloblastoma

BACKGROUND: Recent publications have described an important role for cross talk between PI-3 kinase and sonic hedgehog signaling pathways in the pathogenesis of medulloblastoma. METHODOLOGY/PRINCIPAL FINDINGS: We crossed mice with constitutive activation of Smoothened, SmoA1, with Pten deficient mice. Both constitutive and conditional Pten deficiency doubled the incidence of mice with symptoms of medulloblastoma and resulted in decreased survival. Analysis revealed a clear separation of gene signatures, with up-regulation of genes in the PI-3 kinase signaling pathway, including downstream activation of angiogenesis in SmoA1+/-; Pten +/- medulloblastomas. Western blotting and immunohistochemistry confirmed reduced or absent Pten, Akt activation, and increased angiogenesis in Pten deficient tumors. Down-regulated genes included genes in the sonic hedgehog pathway and tumor suppressor genes. SmoA1+/-; Pten +/+ medulloblastomas appeared classic in histology with increased proliferation and diffuse staining for apoptosis. In contrast, Pten deficient tumors exhibited extensive nodularity with neuronal differentiation separated by focal areas of intense staining for proliferation and virtually absent apoptosis. Examination of human medulloblastomas revealed low to absent PTEN expression in over half of the tumors. Kaplan-Meier analysis confirmed worse overall survival in patients whose tumor exhibited low to absent PTEN expression. CONCLUSIONS/SIGNIFICANCE: This suggests that PTEN expression is a marker of favorable prognosis and mouse models with activation of PI-3 kinase pathways may be important tools for preclinical evaluation of promising agents for the treatment of medulloblastoma

MicroRNA-199b-5p Impairs Cancer Stem Cells through Negative Regulation of HES1 in Medulloblastoma

BACKGROUND: Through negative regulation of gene expression, microRNAs (miRNAs) can function in cancers as oncosuppressors, and they can show altered expression in various tumor types. Here we have investigated medulloblastoma tumors (MBs), which arise from an early impairment of developmental processes in the cerebellum, where Notch signaling is involved in many cell-fate-determining stages. MBs occur bimodally, with the peak incidence seen between 3-4 years and 8-9 years of age, although it can also occur in adults. Notch regulates a subset of the MB cells that have stem-cell-like properties and can promote tumor growth. On the basis of this evidence, we hypothesized that miRNAs targeting the Notch pathway can regulated these phenomena, and can be used in anti-cancer therapies. METHODOLOGY/PRINCIPAL FINDINGS: In a screening of MB cell lines, the miRNA miR-199b-5p was seen to be a regulator of the Notch pathway through its targeting of the transcription factor HES1. Down-regulation of HES1 expression by miR-199b-5p negatively regulates the proliferation rate and anchorage-independent growth of MB cells. MiR-199b-5p over-expression blocks expression of several cancer stem-cell genes, impairs the engrafting potential of MB cells in the cerebellum of athymic/nude mice, and of particular interest, decreases the MB stem-cell-like (CD133+) subpopulation of cells. In our analysis of 61 patients with MB, the expression of miR-199b-5p in the non-metastatic cases was significantly higher than in the metastatic cases (P = 0.001). Correlation with survival for these patients with high levels of miR-199b expression showed a positive trend to better overall survival than for the low-expressing patients. These data showing the down-regulation of miR-199b-5p in metastatic MBs suggest a potential silencing mechanism through epigenetic or genetic alterations. Upon induction of de-methylation using 5-aza-deoxycytidine, lower miR-199b-5p expression was seen in a panel of MB cell lines, supported an epigenetic mechanism of regulation. Furthermore, two cell lines (Med8a and UW228) showed significant up-regulation of miR-199b-5p upon treatment. Infection with MB cells in an induced xenograft model in the mouse cerebellum and the use of an adenovirus carrying miR-199b-5p indicate a clinical benefit through this negative influence of miR-199b-5p on tumor growth and on the subset of MB stem-cell-like cells, providing further proof of concept. CONCLUSIONS/SIGNIFICANCE: Despite advances in our understanding of the pathogenesis of MB, one-third of these patients remain incurable and current treatments can significantly damage long-term survivors. Here we show that miR-199b-5p expression correlates with metastasis spread, identifying a new molecular marker for a poor-risk class in patients with MB. We further show that in a xenograft model, MB tumor burden can be reduced, indicating the use of miR199b-5p as an adjuvant therapy after surgery, in combination with radiation and chemotherapy, for the improvement of anti-cancer MB therapies and patient quality of life. To date, this is the first report that expression of a miRNA can deplete the tumor stem cells, indicating an interesting therapeutic approach for the targeting of these cells in brain tumors

MicroRNAs Dynamically Remodel Gastrointestinal Smooth Muscle Cells

Smooth muscle cells (SMCs) express a unique set of microRNAs (miRNAs) which regulate and maintain the differentiation state of SMCs. The goal of this study was to investigate the role of miRNAs during the development of gastrointestinal (GI) SMCs in a transgenic animal model. We generated SMC-specific Dicer null animals that express the reporter, green fluorescence protein, in a SMC-specific manner. SMC-specific knockout of Dicer prevented SMC miRNA biogenesis, causing dramatic changes in phenotype, function, and global gene expression in SMCs: the mutant mice developed severe dilation of the intestinal tract associated with the thinning and destruction of the smooth muscle (SM) layers; contractile motility in the mutant intestine was dramatically decreased; and SM contractile genes and transcriptional regulators were extensively down-regulated in the mutant SMCs. Profiling and bioinformatic analyses showed that SMC phenotype is regulated by a complex network of positive and negative feedback by SMC miRNAs, serum response factor (SRF), and other transcriptional factors. Taken together, our data suggest that SMC miRNAs are required for the development and survival of SMCs in the GI tract

Enterovirus 71 3C Protease Cleaves a Novel Target CstF-64 and Inhibits Cellular Polyadenylation

Identification of novel cellular proteins as substrates to viral proteases would provide a new insight into the mechanism of cell–virus interplay. Eight nuclear proteins as potential targets for enterovirus 71 (EV71) 3C protease (3Cpro) cleavages were identified by 2D electrophoresis and MALDI-TOF analysis. Of these proteins, CstF-64, which is a critical factor for 3′ pre-mRNA processing in a cell nucleus, was selected for further study. A time-course study to monitor the expression levels of CstF-64 in EV71-infected cells also revealed that the reduction of CstF-64 during virus infection was correlated with the production of viral 3Cpro. CstF-64 was cleaved in vitro by 3Cpro but neither by mutant 3Cpro (in which the catalytic site was inactivated) nor by another EV71 protease 2Apro. Serial mutagenesis was performed in CstF-64, revealing that the 3Cpro cleavage sites are located at position 251 in the N-terminal P/G-rich domain and at multiple positions close to the C-terminus of CstF-64 (around position 500). An accumulation of unprocessed pre-mRNA and the depression of mature mRNA were observed in EV71-infected cells. An in vitro assay revealed the inhibition of the 3′-end pre-mRNA processing and polyadenylation in 3Cpro-treated nuclear extract, and this impairment was rescued by adding purified recombinant CstF-64 protein. In summing up the above results, we suggest that 3Cpro cleavage inactivates CstF-64 and impairs the host cell polyadenylation in vitro, as well as in virus-infected cells. This finding is, to our knowledge, the first to demonstrate that a picornavirus protein affects the polyadenylation of host mRNA