Biomedical subjects

Xiangdong Meng

Publications and source records attributed to Xiangdong Meng.

5 recordsLinked to original sources

PubMed2006

A pilot project for the effective delivery of HAART in rural China.

The purpose of this pilot study, conducted in rural Jilin Province in northeastern China, was to develop and test an infrastructure for the delivery of highly active antiretroviral therapy (HAART) that might be applicable to other such areas across the country. Earlier attempts to provide antiretroviral therapy in rural areas met with mixed success in large measure because of social stigma, a lack of adequate physician training, and problems with patient retention. In response to these problems, a highly integrated and family-centered approach was developed that placed emphasis on the primary care level for regimen delivery. Using this structure, a treatment naïve cohort of 22 male and 20 female (n = 42) volunteers with HIV/acquired immune deficiency syndrome (AIDS) was given government-provided HAART. After 12 months, all volunteers remained in the cohort, and there were significant changes in both CD4 levels and ability to return to work. Per patient cost for the 12-month study was Dollars 1,259.00, with Dollars 1,149 being spent on treatment and Dollars 110.00 on educational and administrative costs. This project demonstrated that HAART can be delivered successfully in resource-poor rural areas in China.

Acquired Immunodeficiency Syndrome↗

PubMed2006

Apple proteins that interact with DspA/E, a pathogenicity effector of Erwinia amylovora, the fire blight pathogen.

The disease-specific (dsp) gene dspA/E of Erwinia amylovora encodes an essential pathogenicity effector of 198 kDa, which is critical to the development of the devastating plant disease fire blight. A yeast two-hybrid assay and in vitro protein pull-down assay demonstrated that DspA/E interacts physically and specifically with four similar putative leucine-rich repeat (LRR) receptor-like serine/threonine kinases (RLK) from apple, an important host of E. amylovora. The genes encoding these four DspA/E-interacting proteins of Malus xdomestica (DIPM1 to 4) are conserved in all genera of hosts of E. amylovora tested. They also are conserved in all cultivars of apple tested that range in susceptibility to fire blight from highly susceptible to highly resistant. The four DIPMs have been characterized, and they are expressed constitutively in host plants. In silico analysis indicated that the DIPMs have similar sequence structure and resemble LRR RLKs from other organisms. Evidence is presented for direct physical interaction between DspA/E and the apple proteins encoded by the four identified clones, which may act as susceptibility factors and be essential to disease development. Knowledge of DIPMs and the interaction with DspA/E thus may facilitate understanding of fire blight development and lead to new approaches to control of disease.

Amino Acid Sequence↗

PubMed2006

Counter-selectable marker for bacterial-based interaction trap systems.

Counter-selectable markers can be used in two-hybrid systems to search libraries for a protein or compound that interferes with a macromolecular interaction or to identify macromolecules from a population that cannot mediate a particular interaction. In this report, we describe the adaptation of the yeast URA3/5-FOA counter-selection system for use in bacterial interaction trap experiments. Two different URA3 reporter systems were developed that allow robust counter-selection: (i) a single copy F' episome reporter and (ii) a co-cistronic HIS3-URA3 reporter vector. The HIS3-URA3 reporter can be used for either positive or negative selections in appropriate bacterial strains. These reagents extend the utility of the bacterial two-hybrid system as an alternative to its yeast-based counterpart.

Escherichia coli↗

PubMed2005

A bacterial one-hybrid system for determining the DNA-binding specificity of transcription factors.

The DNA-binding specificities of transcription factors can be used to computationally predict cis-regulatory modules (CRMs) that regulate gene expression. However, the absence of specificity data for the majority of transcription factors limits the widespread implementation of this approach. We have developed a bacterial one-hybrid system that provides a simple and rapid method to determine the DNA-binding specificity of a transcription factor. Using this technology, we successfully determined the DNA-binding specificity of seven previously characterized transcription factors and one novel transcription factor, the Drosophila melanogaster factor Odd-skipped. Regulatory targets of Odd-skipped were successfully predicted using this information, demonstrating that the data produced by the bacterial one-hybrid system are relevant to in vivo function.

Animals↗

PubMed2004

Downstream divergence of the ethylene signaling pathway for harpin-stimulated Arabidopsis growth and insect defense.

Ethylene (ET) signal transduction may regulate plant growth and defense, depending on which components are recruited into the pathway in response to different stimuli. We report here that the ET pathway controls both insect resistance (IR) and plant growth enhancement (PGE) in Arabidopsis (Arabidopsis thaliana) plants responding to harpin, a protein produced by a plant pathogenic bacterium. PGE may result from spraying plant tops with harpin or by soaking seeds in harpin solution; the latter especially enhances root growth. Plants treated similarly develop resistance to the green peach aphid (Myzus persicae). The salicylic acid pathway, although activated by harpin, does not lead to PGE and IR. By contrast, PGE and IR are induced in both wild-type plants and genotypes that have defects in salicylic acid signaling. In response to harpin, levels of jasmonic acid (JA) decrease, and the COI1 gene, which is indispensable for JA signal transduction, is not expressed in wild-type plants. However, PGE and IR are stimulated in the JA-resistant mutant jar1-1. In the wild type, PGE and IR develop coincidently with increases in ET levels and the expression of several genes essential for ET signaling. The ET receptor gene ETR1 is required because both phenotypes are arrested in the etr1-1 mutant. Consistently, inhibition of ET perception nullifies the induction of both PGE and IR. The signal transducer EIN2 is required for IR, and EIN5 is required for PGE because IR and PGE are impaired correspondingly in the ein2-1 and ein5-1 mutants. Therefore, harpin activates ET signaling while conscribing EIN2 and EIN5 to confer IR and PGE, respectively.

Animals↗