Publications by authors named "Davis W Cheng"

Xylella fastidiosa, the causal agent of Pierce's disease of grapevine, possesses several two-component signal transduction systems that allow the bacterium to sense and respond to changes in its environment. Signals are perceived by sensor kinases that autophosphorylate and transfer the phosphate to response regulators (RRs), which direct an output response, usually by acting as transcriptional regulators. In the X.

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DNA synthesis is the cornerstone of all life forms and is required to replicate and restore the genetic information. Usually, DNA synthesis is carried out only by DNA polymerases semiconservatively to copy preexisting DNA templates. We report here that DNA strands were synthesized ab initio in the absence of any DNA or RNA template by thermophilic DNA polymerases at (a) a constant high temperature (74°C), (b) alternating temperatures (94°C/60°C/74°C), or (c) physiological temperatures (37°C).

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The field of Synthetic Biology seeks to apply engineering principles to biology in order to produce novel biological systems. One approach to accomplish this goal is the genome-driven cell engineering approach, which searches for functioning minimal genomes in naturally occurring microorganisms, which can then be used as a template for future systems. Currently a prototypical minimal genome has not been discovered.

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Background: Plant cytochrome P450 monooxygenases (CYP) mediate synthesis and metabolism of many physiologically important primary and secondary compounds that are related to plant defense against a range of pathogenic microbes and insects. To determine if cytochrome P450 monooxygenases are involved in defense response to Xylella fastidiosa (Xf) infection, we investigated expression and regulatory mechanisms of the cytochrome P450 monooxygenase CYP736B gene in both disease resistant and susceptible grapevines.

Results: Cloning of genomic DNA and cDNA revealed that the CYP736B gene was composed of two exons and one intron with GT as a donor site and AG as an acceptor site.

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Recently we demonstrated that IGF-1 expression is increased in the diabetic kidney and that it may involve in renal hypertrophy and extracellular matrix protein (ECM) accumulation in mesangial cells as seen in diabetic glomerulopathy. The present study investigates the molecular mechanism(s) of IGF-1 and Akt/glycogen synthase kinase-3beta (GSK-3beta) signaling pathway in the regulation of fibronectin and cyclin D1 expression and survival of renal mesangial cells. A proteomic approach is also employed to identify protein targets of IGF-1 signaling via GSK-3beta inhibition in mesangial cells.

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Renal mesangial cells play an important role in the development of diabetic kidney disease. We have previously demonstrated that some of the effects of high glucose on mesangial extracellular matrix (ECM) protein expression are mediated by the hexosamine biosynthesis pathway (HBP) in which fructose-6-phosphate is converted to glucosamine-6-phosphate by the rate-limiting enzyme glutamine:fructose-6-phosphate amidotransferase (GFAT). Using Affymetrix murine expression U430 2.

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We have previously shown that one of the potential mediators of the deleterious effects of high glucose on extracellular matrix protein (ECM) expression in renal mesangial cells is its metabolic flux through the hexosamine biosynthesis pathway (HBP). Here, we investigate further whether the hexosamines induce oxidative stress, cell-cycle arrest and ECM expression using SV-40-transformed rat mesangial (MES) cells and whether the anti-oxidant alpha-lipoic acid will reverse some of these effects. Culturing renal MES cells with high glucose (HG, 25 mM) or glucosamine (GlcN, 1.

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Insulin-like growth factor (IGF)-1 is accumulated in the diabetic kidney and is considered to be involved in the development of glomerular sclerosis. Here, we investigate IGF-1 regulation of laminin, an extracellular matrix (ECM) component, and cyclin D1 and p21Cip1, cell-cycle progression factor, expressions in glomerular mesangial cells. We show that IGF-1 increases the level of laminin gamma1 and beta1 subunits approximately 1.

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The transforming growth factor-beta (TGF-beta) 1 is a mediator of extracellular matrix (ECM) gene expression in mesangial cells and the development of diabetic glomerulopathy. Here, we investigate the effects of TGF-beta1 on laminin gamma1 and fibronectin polypeptide expression and cell survival in mouse mesangial cells (MES-13). TGF-beta1 (10 ng/ml) stimulates laminin-gamma1 and fibronectin expression approximately two-fold in a time-dependent manner (0-48 h).

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A direct DNA capture and cloning procedure with magnetic bead separation was used to isolate receptor kinase like and peroxidase genes from oat (Avena sativa) and wheat (Triticum aestivum L.) genomic DNA, respectively. In this procedure, the digoxigenin-labeled probe DNA and target genomic DNA fragments were mixed, denatured, and hybridized.

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Oat receptor-like kinase gene sequences, homologous to the Lrk10 gene from wheat (Triticum aestivum L.), were mapped in oat (Avena sativa L.).

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