Genetic and Biotypic Diversity of Greenbug Schizaphis Graminum (Rondani) Populations on Non-cultivated Hosts

Chapter I of this thesis is an introduction and literature review focusing on the history and biology of Schizaphis graminum. It concentrates on host use and biotypes. Chapters II, III and IV are formal manuscripts of the research I conducted during my M.S. program and are written in compliance with the publication policies and guidelines for manuscript preparation with the appropriate journals

Broccoli (Brassica oleracea) phloem tissue proteome

Background: The transport of sugars, hormones, amino acids, proteins, sugar alcohols, and other organic compounds from the sites of synthesis to the sites of use or storage occurs through the conducting cells of the phloem. To better understand these processes a comprehensive understanding of the proteins involved is required. While a considerable amount of data has been obtained from proteomic analyses of phloem sap, this has mainly served to identify the soluble proteins that are translocated through the phloem network.Results: In order to obtain more comprehensive proteomic data from phloem tissue we developed a simple dissection procedure to isolate phloem tissue from Brassica oleracea. The presence of a high density of phloem sieve elements was confirmed using light microscopy and fluorescently labeled sieve element-specific antibodies. To increase the depth of the proteomic analysis for membrane bound and associated proteins, soluble proteins were extracted first and subsequent extractions were carried out using two different detergents (SDS and CHAPSO). Across all three extractions almost four hundred proteins were identified and each extraction method added to the analysis demonstrating the utility of an approach combining several extraction protocols.Conclusions: The phloem was found to be enriched in proteins associated with biotic and abiotic stress responses and structural proteins. Subsequent expression analysis identified a number of genes that appear to be expressed exclusively or at very high levels in phloem tissue, including genes that are known to express specifically in the phloem as well as novel phloem genes.Peer reviewedBiochemistry and Molecular Biolog

Complexities of Assessing the Disease Burden Attributable to Leishmaniasis

Among parasitic diseases, morbidity and mortality caused by leishmaniasis are surpassed only by malaria and lymphatic filariasis. However, estimation of the leishmaniasis disease burden is challenging, due to clinical and epidemiological diversity, marked geographic clustering, and lack of reliable data on incidence, duration, and impact of the various disease syndromes. Non-health effects such as impoverishment, disfigurement, and stigma add to the burden, and introduce further complexities. Leishmaniasis occurs globally, but has disproportionate impact in the Horn of Africa, South Asia and Brazil (for visceral leishmaniasis), and Latin America, Central Asia, and southwestern Asia (for cutaneous leishmaniasis). Disease characteristics and challenges for control are reviewed for each of these foci. We recommend review of reliable secondary data sources and collection of baseline active survey data to improve current disease burden estimates, plus the improvement or establishment of effective surveillance systems to monitor the impact of control efforts

Circulating microRNAs in sera correlate with soluble biomarkers of immune activation but do not predict mortality in ART treated individuals with HIV-1 infection: A case control study

Introduction: The use of anti-retroviral therapy (ART) has dramatically reduced HIV-1 associated morbidity and mortality. However, HIV-1 infected individuals have increased rates of morbidity and mortality compared to the non-HIV-1 infected population and this appears to be related to end-organ diseases collectively referred to as Serious Non-AIDS Events (SNAEs). Circulating miRNAs are reported as promising biomarkers for a number of human disease conditions including those that constitute SNAEs. Our study sought to investigate the potential of selected miRNAs in predicting mortality in HIV-1 infected ART treated individuals. Materials and Methods: A set of miRNAs was chosen based on published associations with human disease conditions that constitute SNAEs. This case: control study compared 126 cases (individuals who died whilst on therapy), and 247 matched controls (individuals who remained alive). Cases and controls were ART treated participants of two pivotal HIV-1 trials. The relative abundance of each miRNA in serum was measured, by RTqPCR. Associations with mortality (all-cause, cardiovascular and malignancy) were assessed by logistic regression analysis. Correlations between miRNAs and CD4+ T cell count, hs-CRP, IL-6 and D-dimer were also assessed. Results: None of the selected miRNAs was associated with all-cause, cardiovascular or malignancy mortality. The levels of three miRNAs (miRs -21, -122 and -200a) correlated with IL-6 while miR-21 also correlated with D-dimer. Additionally, the abundance of miRs -31, -150 and -223, correlated with baseline CD4+ T cell count while the same three miRNAs plus miR- 145 correlated with nadir CD4+ T cell count. Discussion: No associations with mortality were found with any circulating miRNA studied. These results cast doubt onto the effectiveness of circulating miRNA as early predictors of mortality or the major underlying diseases that contribute to mortality in participants treated for HIV-1 infection

Development and Validation of a Risk Score for Chronic Kidney Disease in HIV Infection Using Prospective Cohort Data from the D:A:D Study

Ristola M. on työryhmien DAD Study Grp ; Royal Free Hosp Clin Cohort ; INSIGHT Study Grp ; SMART Study Grp ; ESPRIT Study Grp jäsen.Background Chronic kidney disease (CKD) is a major health issue for HIV-positive individuals, associated with increased morbidity and mortality. Development and implementation of a risk score model for CKD would allow comparison of the risks and benefits of adding potentially nephrotoxic antiretrovirals to a treatment regimen and would identify those at greatest risk of CKD. The aims of this study were to develop a simple, externally validated, and widely applicable long-term risk score model for CKD in HIV-positive individuals that can guide decision making in clinical practice. Methods and Findings A total of 17,954 HIV-positive individuals from the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study with >= 3 estimated glomerular filtration rate (eGFR) values after 1 January 2004 were included. Baseline was defined as the first eGFR > 60 ml/min/1.73 m2 after 1 January 2004; individuals with exposure to tenofovir, atazanavir, atazanavir/ritonavir, lopinavir/ritonavir, other boosted protease inhibitors before baseline were excluded. CKD was defined as confirmed (>3 mo apart) eGFR In the D:A:D study, 641 individuals developed CKD during 103,185 person-years of follow-up (PYFU; incidence 6.2/1,000 PYFU, 95% CI 5.7-6.7; median follow-up 6.1 y, range 0.3-9.1 y). Older age, intravenous drug use, hepatitis C coinfection, lower baseline eGFR, female gender, lower CD4 count nadir, hypertension, diabetes, and cardiovascular disease (CVD) predicted CKD. The adjusted incidence rate ratios of these nine categorical variables were scaled and summed to create the risk score. The median risk score at baseline was -2 (interquartile range -4 to 2). There was a 1: 393 chance of developing CKD in the next 5 y in the low risk group (risk score = 5, 505 events), respectively. Number needed to harm (NNTH) at 5 y when starting unboosted atazanavir or lopinavir/ritonavir among those with a low risk score was 1,702 (95% CI 1,166-3,367); NNTH was 202 (95% CI 159-278) and 21 (95% CI 19-23), respectively, for those with a medium and high risk score. NNTH was 739 (95% CI 506-1462), 88 (95% CI 69-121), and 9 (95% CI 8-10) for those with a low, medium, and high risk score, respectively, starting tenofovir, atazanavir/ritonavir, or another boosted protease inhibitor. The Royal Free Hospital Clinic Cohort included 2,548 individuals, of whom 94 individuals developed CKD (3.7%) during 18,376 PYFU (median follow-up 7.4 y, range 0.3-12.7 y). Of 2,013 individuals included from the SMART/ESPRIT control arms, 32 individuals developed CKD (1.6%) during 8,452 PYFU (median follow-up 4.1 y, range 0.6-8.1 y). External validation showed that the risk score predicted well in these cohorts. Limitations of this study included limited data on race and no information on proteinuria. Conclusions Both traditional and HIV-related risk factors were predictive of CKD. These factors were used to develop a risk score for CKD in HIV infection, externally validated, that has direct clinical relevance for patients and clinicians to weigh the benefits of certain antiretrovirals against the risk of CKD and to identify those at greatest risk of CKD.Peer reviewe

Arabidopsis P-protein filament formation requires both AtSEOR1 and AtSEOR2

The structure-function relationship of proteinaceous filaments in sieve elements has long been a source of investigation in order to understand their role in the biology of the phloem. Two phloem filament proteins AtSEOR1 (At3g01680.1) and AtSEOR2 (At3g01670.1) in Arabidopsis have been identified that are required for filament formation. Immunolocalization experiments using a phloem filament-specific monoclonal antibody in the respective T-DNA insertion mutants provided an initial indication that both proteins are necessary to form phloem filaments. To investigate the relationship between these two proteins further, green fluorescent protein (GFP)-AtSEO fusion proteins were expressed in Columbia wild-type and T-DNA insertion mutants. Analysis of these mutants by confocal microscopy confirmed that phloem filaments could only be detected in the presence of both proteins, indicating that despite significant sequence homology the proteins are not functionally redundant. Individual phloem filament protein subunits of AtSEOR1 and AtSEOR2 were capable of forming homodimers, but not heterodimers in a yeast two-hybrid system. The absence of phloem filaments in phloem sieve elements did not result in gross alterations of plant phenotype or affect basal resistance to green peach aphid (Myzus persicae)

Insecticide resistance: from science to practice.

Williamson M.S., Anstead J.A., Devine G.J., Devonshire A.L., Field L.M., Foster S.P., Moores G.D., Denholm A., (2003), Insecticide resistance: from science to practice, Paper presented at the British Crop Production Council (BCPC) Conference, Glasgow, UK, 10-12 November, 2003, ISBN 1 901396 63 0, published by BCPC

Expression of Small RNA in <i>Aphis gossypii</i> and Its Potential Role in the Resistance Interaction with Melon

<div><p>Background</p><p>The regulatory role of small RNAs (sRNAs) in various biological processes is an active area of investigation; however, there has been limited information available on the role of sRNAs in plant-insect interactions. This study was designed to identify sRNAs in cotton-melon aphid (<i>Aphis gossypii</i>) during the <i>Vat</i>-mediated resistance interaction with melon (<i>Cucumis melo</i>).</p><p>Methodology/Principal Findings</p><p>The role of miRNAs was investigated in response to aphid herbivory, during both resistant and susceptible interactions. sRNA libraries made from <i>A. gossypii</i> tissues feeding on <i>Vat⁺</i> and <i>Vat⁻</i> plants revealed an unexpected abundance of 27 nt long sRNA sequences in the aphids feeding on <i>Vat⁺</i> plants. Eighty-one conserved microRNAs (miRNAs), twelve aphid-specific miRNAs, and nine novel candidate miRNAs were also identified. Plant miRNAs found in the aphid libraries were most likely ingested during phloem feeding. The presence of novel miRNAs was verified by qPCR experiments in both resistant <i>Vat⁺</i> and susceptible <i>Vat⁻</i> interactions. The comparative analyses revealed that novel miRNAs were differentially regulated during the resistant and susceptible interactions. Gene targets predicted for the miRNAs identified in this study by <i>in silico</i> analyses revealed their involvement in morphogenesis and anatomical structure determination, signal transduction pathways, cell differentiation and catabolic processes.</p><p>Conclusion/Significance</p><p>In this study, conserved and novel miRNAs were reported in <i>A. gossypii</i>. Deep sequencing data showed differences in the abundance of miRNAs and piRNA-like sequences in <i>A. gossypii</i>. Quantitative RT-PCR revealed that <i>A. gossypii</i> miRNAs were differentially regulated during resistant and susceptible interactions. Aphids can also ingest plant miRNAs during phloem feeding that are stable in the insect.</p></div