27 research outputs found

    Comparison of the transcriptomes of American chestnut (Castanea dentata) and Chinese chestnut (Castanea mollissima) in response to the chestnut blight infection

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    <p>Abstract</p> <p>Background1471-2229-9-51</p> <p>American chestnut (<it>Castanea dentata</it>) was devastated by an exotic pathogen in the beginning of the twentieth century. This chestnut blight is caused by <it>Cryphonectria parasitica</it>, a fungus that infects stem tissues and kills the trees by girdling them. Because of the great economic and ecological value of this species, significant efforts have been made over the century to combat this disease, but it wasn't until recently that a focused genomics approach was initiated. Prior to the Genomic Tool Development for the Fagaceae project, genomic resources available in public databases for this species were limited to a few hundred ESTs. To identify genes involved in resistance to <it>C. parasitica</it>, we have sequenced the transcriptome from fungal infected and healthy stem tissues collected from blight-sensitive American chestnut and blight-resistant Chinese chestnut (<it>Castanea mollissima</it>) trees using ultra high throughput pyrosequencing.</p> <p>Results</p> <p>We produced over a million 454 reads, totaling over 250 million bp, from which we generated 40,039 and 28,890 unigenes in total from <it>C. mollissima </it>and <it>C. dentata </it>respectively.</p> <p>The functions of the unigenes, from GO annotation, cover a diverse set of molecular functions and biological processes, among which we identified a large number of genes associated with resistance to stresses and response to biotic stimuli. <it>In silico </it>expression analyses showed that many of the stress response unigenes were expressed more in canker tissues versus healthy stem tissues in both American and Chinese chestnut. Comparative analysis also identified genes belonging to different pathways of plant defense against biotic stresses that are differentially expressed in either American or Chinese chestnut canker tissues.</p> <p>Conclusion</p> <p>Our study resulted in the identification of a large set of cDNA unigenes from American chestnut and Chinese chestnut. The ESTs and unigenes from this study constitute an important resource to the scientific community interested in the discovery of genes involved in various biological processes in Chestnut and other species. The identification of many defense-related genes differentially expressed in canker vs. healthy stem in chestnuts provides many new candidate genes for developing resistance to the chestnut blight and for studying pathways involved in responses of trees to necrotrophic pathogens. We also identified several candidate genes that may underline the difference in resistance to <it>Cryphonectria parasitica </it>between American chestnut and Chinese chestnut.</p

    A low-cost intervention for cleaner drinking water in Karachi, Pakistan

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    Objective: To pilot test an inexpensive, home-based water decontamination and storage system in a low-income neighborhood of Karachi.Methods: Fifty households received a 20-L plastic water storage vessel with a high-quality spout and a regular supply of diluted hypochlorite solution. Twenty-five control households were recruited. Water samples were collected at baseline and during unannounced follow-up visits 1, 3, 6, and 10 weeks later.Results: Baseline drinking water samples among intervention households were contaminated with a mean 9397 colony-forming units (cfu)/100 mL of thermotolerant coliforms compared with a mean 10,990 cfu/100 mL from controls. After intervention the mean concentration of thermotolerant coliforms decreased by 99.8% among the intervention households compared with an 8% reduction among controls. Two years after vessel distribution, 34 (68%) of the families were still using the vessel. Thirteen of the households had stopped using their vessel because it had broken after more than 6 months of use, a pattern most consistent with ultraviolet radiation-induced degradation of the plastic.CONCLUSIONS: In a highly contaminated environment, a specifically designed water storage container and in-home water chlorination was acceptable and markedly improved water quality. Where plastic water vessels will be exposed to substantial sunlight, ultraviolet light stabilizers should be incorporated into the plastic

    Genome-wide Association Study of Platelet Count Identifies Ancestry-Specific Loci in Hispanic/Latino Americans

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    Platelets play an essential role in hemostasis and thrombosis. We performed a genome-wide association study of platelet count in 12,491 participants of the Hispanic Community Health Study/Study of Latinos by using a mixed-model method that accounts for admixture and family relationships. We discovered and replicated associations with five genes (ACTN1, ETV7, GABBR1-MOG, MEF2C, and ZBTB9-BAK1). Our strongest association was with Amerindian-specific variant rs117672662 (p value = 1.16 × 10−28) in ACTN1, a gene implicated in congenital macrothrombocytopenia. rs117672662 exhibited allelic differences in transcriptional activity and protein binding in hematopoietic cells. Our results underscore the value of diverse populations to extend insights into the allelic architecture of complex traits

    Disparities in preventive procedures: comparisons of self-report and Medicare claims data

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    BACKGROUND: Racial/ethnic disparities are assessed using either self-report or claims data. We compared these two data sources and examined contributors to discrepancies in estimates of disparities. METHODS: We analyzed self-report and matching claims data from Medicare Beneficiaries 65 and older who participated in the Medicare Current Beneficiary Survey, 1999–2002. Six preventive procedures were included: PSA testing, influenza vaccination, Pap smear testing, cholesterol testing, mammography, and colorectal cancer testing. We examined predictors of self-reports in the absence of claims and claims in the absence of self-reports. RESULTS: With the exception of PSA testing, racial/ethnic disparities in preventive procedures are generally larger when using Medicare claims than when using patients' self-report. Analyses adjusting for age, gender, income, educational level, health status, proxy response and supplemental insurance showed that minorities were more likely to self-report preventive procedures in the absence of claims. Adjusted odds ratios ranged from 1.07 (95% CI: 0.88 – 1.30) for PSA testing to 1.83 (95% CI: 1.46 – 2.30) for Pap smear testing. Rates of claims in the absence of self-report were low. Minorities were more likely to have PSA test claims in the absence of self-reports (1.55 95% CI: 1.17 – 2.06), but were less likely to have influenza vaccination claims in the absence of self-reports (0.69 95% CI: 0.51 – 0.93). CONCLUSION: These findings are consistent with either racial/ethnic reporting biases in receipt of preventive procedures or less efficient Medicare billing among providers with large minority practices

    Chestnut resistance to the blight disease: insights from transcriptome analysis

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    Abstract Background A century ago, Chestnut Blight Disease (CBD) devastated the American chestnut. Backcross breeding has been underway to introgress resistance from Chinese chestnut into surviving American chestnut genotypes. Development of genomic resources for the family Fagaceae, has focused in this project on Castanea mollissima Blume (Chinese chestnut) and Castanea dentata (Marsh.) Borkh (American chestnut) to aid in the backcross breeding effort and in the eventual identification of blight resistance genes through genomic sequencing and map based cloning. A previous study reported partial characterization of the transcriptomes from these two species. Here, further analyses of a larger dataset and assemblies including both 454 and capillary sequences were performed and defense related genes with differential transcript abundance (GDTA) in canker versus healthy stem tissues were identified. Results Over one and a half million cDNA reads were assembled into 34,800 transcript contigs from American chestnut and 48,335 transcript contigs from Chinese chestnut. Chestnut cDNA showed higher coding sequence similarity to genes in other woody plants than in herbaceous species. The number of genes tagged, the length of coding sequences, and the numbers of tagged members within gene families showed that the cDNA dataset provides a good resource for studying the American and Chinese chestnut transcriptomes. In silico analysis of transcript abundance identified hundreds of GDTA in canker versus healthy stem tissues. A significant number of additional DTA genes involved in the defense-response not reported in a previous study were identified here. These DTA genes belong to various pathways involving cell wall biosynthesis, reactive oxygen species (ROS), salicylic acid (SA), ethylene, jasmonic acid (JA), abscissic acid (ABA), and hormone signalling. DTA genes were also identified in the hypersensitive response and programmed cell death (PCD) pathways. These DTA genes are candidates for host resistance to the chestnut blight fungus, Cryphonectria parasitica. Conclusions Our data allowed the identification of many genes and gene network candidates for host resistance to the chestnut blight fungus, Cryphonectria parasitica. The similar set of GDTAs in American chestnut and Chinese chestnut suggests that the variation in sensitivity to this pathogen between these species may be the result of different timing and amplitude of the response of the two to the pathogen infection. Resources developed in this study are useful for functional genomics, comparative genomics, resistance breeding and phylogenetics in the Fagaceae.</p

    A Randomized Trial to Increase Colonoscopy Screening in Members of High-Risk Families in the Colorectal Cancer Family Registry and Cancer Genetics Network

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    BACKGROUND: Individuals with a strong family history of colorectal cancer (CRC) have significant risk for CRC, though adherence to colonoscopy screening in these groups remains low. This study assessed whether a tailored, telephone counseling intervention can increase adherence to colonoscopy in members of high risk families in a randomized, controlled trial. METHODS: Eligible participants were recruited from two national cancer registries if they had a first-degree relative with CRC under age 60 or multiple affected family members, which included families that met Amsterdam criteria for Hereditary Non-Polyposis Colon Cancer, and if they were due for colonoscopy within 24-months. Participants were randomized to receive a tailored, telephone intervention grounded in behavioral theory or a mailed packet with general information about screening. Colonoscopy status was assessed through follow-up surveys and endoscopy reports. Cox-proportional hazards models were used to assess intervention effect. RESULTS: Of the 632 participants (aged 25–80), 60% were female, the majority were White, non-Hispanic, educated and had health insurance. Colonoscopy adherence increased 11 percentage points in the tailored, telephone intervention group, compared to no significant change in the mailed group. The telephone intervention was associated with a 32% increase in screening adherence compared to the mailed intervention (Hazard Ratio=1.32; p=0.01). CONCLUSIONS: A tailored, telephone intervention can effectively increase colonoscopy adherence in high risk persons. This intervention has the potential for broad dissemination to health-care organizations or other high risk populations. IMPACT: Increasing adherence to colonoscopy among persons with increased CRC risk could effectively reduce incidence and mortality from this disease
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