Steviol Reduces MDCK Cyst Formation and Growth by Inhibiting CFTR Channel Activity and Promoting Proteasome-Mediated CFTR Degradation

Cyst enlargement in polycystic kidney disease (PKD) involves cAMP-activated proliferation of cyst-lining epithelial cells and transepithelial fluid secretion into the cyst lumen via cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. This study aimed to investigate an inhibitory effect and detailed mechanisms of steviol and its derivatives on cyst growth using a cyst model in Madin-Darby canine kidney (MDCK) cells. Among 4 steviol-related compounds tested, steviol was found to be the most potent at inhibiting MDCK cyst growth. Steviol inhibition of cyst growth was dose-dependent; steviol (100 microM) reversibly inhibited cyst formation and cyst growth by 72.53.6% and 38.2±8.5%, respectively. Steviol at doses up to 200 microM had no effect on MDCK cell viability, proliferation and apoptosis. However, steviol acutely inhibited forskolin-stimulated apical chloride current in MDCK epithelia, measured with the Ussing chamber technique, in a dose-dependent manner. Prolonged treatment (24 h) with steviol (100 microM) also strongly inhibited forskolin-stimulated apical chloride current, in part by reducing CFTR protein expression in MDCK cells. Interestingly, proteasome inhibitor, MG-132, abolished the effect of steviol on CFTR protein expression. Immunofluorescence studies demonstrated that prolonged treatment (24 h) with steviol (100 microM) markedly reduced CFTR expression at the plasma membrane. Taken together, the data suggest that steviol retards MDCK cyst progression in two ways: first by directly inhibiting CFTR chloride channel activity and second by reducing CFTR expression, in part, by promoting proteasomal degradation of CFTR. Steviol and related compounds therefore represent drug candidates for treatment of polycystic kidney disease.     

Resource use and improvement strategy analysis of the livestock and feed production supply chain in Thailand

Purpose

The aim of this research is to reveal the overall money flows and physical flows of the livestock and feed production supply chain in Thailand in order to analyze the resource use and cost and assess material use efficiency of the whole supply chain. Another aim is to evaluate the options to improve and evaluate trade-off between economic and environmental performance.

Methods

This research conducted material and monetary flow modeling using material flow analysis (MFA) and input output analysis (IOA). Data collected from the Thai Input-Output Tables 2005 were employed to develop the monetary flow model. Direct and indirect resource consumption (energy, water, and land use) and turnover along the supply chain were assessed using environmentally extended input-output analysis model (EEIOA). Scenario analysis with improvement options was applied to the model to evaluate the effectiveness of the improvement options.

Results and discussion

One third of energy and water consumption were from the animal farm itself. The rest were from feed production and upstream raw material production. Land use in the system was mainly from maize and paddy field. Feed conversion ratio improvement should play an important role in the strategy for resource efficiency and reduce environmental impact in the whole supply chain. Energy intensity reduction, the best option in overall energy reduction, is the policy that the government is pushing to be implemented in all sectors, and it can also easily be applied along with the other options. Therefore, it should be applied with the other options for improvement.

Conclusions

The results from monetary flow and physical material flow can visually show the holistic view of the Thai livestock production supply chain quantitatively and allow the stakeholders to understand the economic structure of the supply chain system. This can enable the decision makers to analyze the interrelation effect and impact of changing one sector demand or changing resource efficiency to impact other sectors in the system.

     

Agrobacterium rhizogenes-mediated transformation of soybean to study root biology

This protocol is used to induce transgenic roots on soybean to study the function of genes required in biological processes of the root. Young seedlings with unfolded cotyledons are infected at the cotyledonary node and/or hypocotyl with Agrobacterium rhizogenes carrying the gene construct to be tested and the infection sites are kept in an environment of high humidity. When the emerged hairy roots can support the plants, the main roots are removed and the transgenic roots can be tested. Using this method, almost 100% of the infected plants form hairy roots within 1 month from the start of the experiments.     

Documenting a thousand years of environmental and anthropogenic changes on mangroves on the Bangkok coast,the upper Gulf of Thailand

Vegetation History and Archaeobotany - Environmental changes and human activities in a mangrove ecosystem in Bang Khun Thian, south of Bangkok, the upper Gulf of Thailand were reconstructed through...     

Sequence variation of avirulence gene AVR-Pita1 in rice blast fungus, Magnaporthe oryzae

The interaction between rice, Oryza sativa, and rice blast fungus, Magnaporthe oryzae, is triggered by an interaction between the protein products of the host resistant gene, and the pathogen avirulence gene. This interaction follows the ‘gene-for-gene' concept. The resistant gene has effectively protected rice plants from rice blast infection. However, the resistant genes usually break down several years after the release of the resistant rice varieties because the fungus has evolved to new races. The objective of this study is to investigate the nucleotide sequence variation of the AVR-Pita1 gene that influences the adaption of rice blast fungus to overcome the resistant gene, Pi-ta. Thirty rice blast fungus isolates were collected in 2005 and 2010 from infected rice plants in northern and northeastern Thailand. The nucleotide sequences of AVR-Pita1 were amplified and analyzed. Phylogenetic analysis was conducted using the MEGA 5.0 program. The results showed a high level of nucleotide sequence polymorphisms and the positive genetic selection pressure in Thai rice blast isolates. The details of sequence variation analysis were described in this article. The information from this study can be used for rice blast resistant breeding program in the future.     

Ultrasensitive determination of absolute mRNA amounts at attomole levels of nearly identical plant genes with high-throughput mass spectrometry (MassARRAY)

Detection of very small amounts of RNA based on microdissection of plant tissue is essential for modern plant biology. Mass spectroscopy technology (MassARRAY) based on Sequenomtrade mark instrumentation was adapted to determine quickly and in a high-throughput fashion (by multiplexing) the absolute amounts of mRNA of closely related soybean genes. A sensitivity of 0.1 amol (10(-19)) was achieved, representing as few as 1,000 mRNA molecules. This methodology eliminates the use of housekeeping genes as reference standards and has multiple applications for plant functional genomics, such as the monitoring of individual expression of paralogous genes at ultra-low expression levels and/or in extremely small tissue samples.     

Hepatocyte nuclear factor 4α regulates the expression of the murine pyruvate carboxylase gene through the HNF4-specific binding motif in its proximal promoter

Pyruvate carboxylase (PC) is the first regulatory enzyme of gluconeogenesis. Here we report that the proximal promoter of the murine PC gene contains three binding sites for hepatocyte nuclear factor 4α (HNF4α). These sites include the classical direct repeat 1 (DR1) (− 386/− 374), non-perfect DR1 (− 118/− 106) and HNF4α-specific binding motif (H4-SBM) (− 26/− 14). Under basal conditions, mutation of the non-perfect DR1 decreased promoter activity by 50%, whereas mutation of neither the DR1 nor the H4-SBM had any effect. In marked contrast, only mutation of the H4-SBM decreased HNF4α-transactivation of the promoter activity by 65%. EMSA revealed that HNF4α binds to the DR1site and H4-SBM with similar affinity while it binds poorly to the non-perfect DR1. Interestingly, this non-perfect DR1 also coincides with two E-boxes. Mutation of the non-perfect DR1 together with the nearby E-box reduced USF1- but not USF2-transactivation of promoter activity, suggesting that USF1 partly contributes to the basal activity of the promoter. Substitution of the H4-SBM with the DR1 marginally reduced the basal promoter activity but did not eliminate HNF4α-transactivation, suggesting that HNF4α can exert its effect via DR1 within this promoter context. ChIP-assay confirmed that HNF4α is associated with the H4-SBM. Suppression of HNF4α expression in AML12 cells down-regulated PC mRNA and PC protein by 60% and 50%, respectively, confirming that PC is a target of HNF4α. We also propose a model for differential regulation of P1 promoter of PC gene in adipose tissue and liver.