Computational models in plant-pathogen interactions: the case of Phytophthora infestans

<p>Abstract</p> <p>Background</p> <p><it>Phytophthora infestans </it>is a devastating oomycete pathogen of potato production worldwide. This review explores the use of computational models for studying the molecular interactions between <it>P. infestans </it>and one of its hosts, <it>Solanum tuberosum</it>.</p> <p>Modeling and conclusion</p> <p>Deterministic logistics models have been widely used to study pathogenicity mechanisms since the early 1950s, and have focused on processes at higher biological resolution levels. In recent years, owing to the availability of high throughput biological data and computational resources, interest in stochastic modeling of plant-pathogen interactions has grown. Stochastic models better reflect the behavior of biological systems. Most modern approaches to plant pathology modeling require molecular kinetics information. Unfortunately, this information is not available for many plant pathogens, including <it>P. infestans</it>. Boolean formalism has compensated for the lack of kinetics; this is especially the case where comparative genomics, protein-protein interactions and differential gene expression are the most common data resources.</p

A holistic framework of corporate website favourability

This paper extends the current knowledge of corporate website favourability (CWF) by developing a comprehensive conceptual model of its influence on corporate image, corporate reputation, loyalty and identification. The paper reviews previous studies on corporate websites from the perspectives of marketing, management, corporate identity and corporate visual identity in order to inform our understanding of the antecedents and consequences of CWF. The propositions and the conceptual framework present an approach by which a corporation can design and manage a favourable corporate website. A number of important contributions are offered: First, the paper adds to the understanding of CWF; second, it discusses the antecedents of CWF by drawing upon the existing literature; third, it is beneficial for practitioners in shaping CWF strategies, and fourth, it offers possible consequences of CWF and provides a framework for future testing

Urinary incontinence in the elderly: attitudes and experiences of general practitioners. A focus group study.

Contains fulltext : 50429.pdf (publisher's version ) (Open Access)OBJECTIVE: To assess general practitioners' (GPs') attitudes to urinary incontinence in elderly patients and their experiences in the application of the Dutch College of General Practitioners' guideline in daily practice. DESIGN: Two existed groups of six GPs working in villages and seven GPs working in urban practices. METHOD: Two focus-group discussions with recording of discussions and transcription. Transcripts were analysed by two independent researchers. RESULTS: During the discussions three main themes of attitudes came forward: (1) therapeutic nihilism of GPs and low motivation of patients, (2): GPs experienced lack of time because of difficulties in explaining the therapy and because of impaired mobility of older patients, (3) because of the complexity of the problem and co-morbidity, GPs as well as patients were reluctant to treat the UI. The most remarkable findings in the application of the guideline were: (1) because of the barriers mentioned above, physical examination did not take place in spite of GPs' conviction as to the benefit of it; (2) GPs' knowledge of treatment options in the elderly with UI is substandard. CONCLUSION: Several patient (comorbidity, impaired mobility, low motivation, and acceptance of the problem) and GP factors (therapeutic nihilism, lack of time and knowledge) interfere with good management of UI in the elderly

"It can always happen": the impact of urinary incontinence on elderly men and women.

Contains fulltext : 50950.pdf (publisher's version ) (Open Access

Changes in the pattern of service utilisation and health problems of women, men and various age groups following a destructive disaster: a matched cohort study with a pre-disaster assessment.

Contains fulltext : 69779.pdf (publisher's version ) (Open Access)OBJECTIVES: Female gender and young age are known risk factors for psychological morbidity after a disaster, but this conclusion is based on studies without a pre-disaster assessment. The aim of this study in family practice was to investigate if these supposed risk factors would still occur in a study design with a pre-disaster measurement. METHODS: A matched cohort study with pre-disaster (one year) and post-disaster (five years) data. Community controls (N = 3164) were matched with affected residents (N = 3164) on gender, age and socioeconomic status. Main outcome measures were utilization rates measured by family practice attendances and psychological, musculoskeletal and digestive health problems as registered by the family practitioner using the International Classification of Primary Care (ICPC). RESULTS: Affected residents of female and male gender and in five age groups all showed increases in utilization rates in the first post-disaster year and in psychological problems when compared to their pre-disaster baseline levels. The increases showed no statistically significant changes, however, between women and men and between all age groups. CONCLUSION: Gender and age did not appear to be disaster-related risk factors in this study in family practice with a pre-disaster base line assessment, a comparison group and using existing registries. Family practitioners should not focus specifically on these risk groups

Phase Variation in the Helicobacter pylori Phospholipase A Gene and Its Role in Acid Adaptation

Previously, we have shown that Helicobacter pylori can spontaneously and reversibly change its membrane lipid composition, producing variants with low or high content of lysophospholipids. The “lyso” variant contains a high percentage of lysophospholipids, adheres better to epithelial cells, and releases more proteins such as urease and VacA, compared to the “normal” variant, which has a low content of lysophospholipids. Prolonged growth of the normal variant at pH 3.5, but not under neutral conditions, leads to enrichment of lyso variant colonies, suggesting that the colony switch is relevant to acid adaptation. In this study we show that the change in membrane lipid composition is due to phase variation in the pldA gene. A change in the (C) tract length of this gene results in reversible frameshifts, translation of a full-length or truncated pldA, and the production of active or inactive outer membrane phospholipase A (OMPLA). The role of OMPLA in determining the colony morphology was confirmed by the construction of an OMPLA-negative mutant. Furthermore, variants with an active OMPLA were able to survive acidic conditions better than variants with the inactive form. This explains why the lyso variant is selected at low pH. Our studies demonstrate that phase variation in the pldA gene, resulting in an active form of OMPLA, is important for survival under acidic conditions. We also demonstrated the active OMPLA genotype in fresh isolates of H. pylori from patients referred to gastroscopy for dyspepsia