Interaction of Arabidopsis Thaliana with Plasmodiophora Brassicae

Plasmodiophora brassicae is a protistan pathogen that attacks roots of brassicaceous plant species causing devastating disease. Resistance is characterised by restriction of the pathogen and susceptibility by the development of severely malformed roots (&lsquo;clubroots&rsquo;) and stunting of the plant that is associated with alterations in the synthesis of cytokinin and auxin hormones. We are examining the susceptible response in Arabidopsis and whether suppression of key resistance factors by the pathogen contributes to susceptibility. The interaction is being studied using a number of approaches including microscopy of the infection process and development of the pathogen within roots and host gene expression analysis. Quantitative PCR was used to confirm the timing of infection of roots and showed that infection occurred at day four and colonisation increased thereafter to high levels by 23 days after inoculation by which time roots were showing systemic abnormalities. To investigate the basis of this compatible interaction we have conducted a time course experiment following infection of a susceptible ecotype of Arabidopsis (Col-0) to examine whole genome geneexpression changes in the host. Differential gene expression analysis of inoculated versus control roots showed that a higher number of genes had altered expression levels at day four compared to that at day seven and at day ten. At day four the expression levels of several genes known to be important for recognition and signal transduction in resistant interactions and genes involved in the biosynthesis of lignin, phenylpropanoids and ethylene were suppressed. Suppression by P. brassicae of specific plant defence responses appears to be a key component of susceptibility in this system.<br /

Land Settlement Act Amendment Act, 1957, No. 26

In recent years, there has been a widespread interest in the economic development role played by 'Bohemian' occupations and the 'creative class'. It is believed that creative people and occupations generate external effects which foster economic growth. However, the degree to which these externalities affect production and consumption is as yet not clear. As part of this debate, we investigate the ability of creative individuals to internalize the rents accruing from creative occupations in comparison with other types of activities. In order to do this, the paper analyzes the employment opportunities and wages earned by graduates in artistic occupations (Bohemians) and compares them with those of non-Bohemians. Using a uniquely longitudinal dataset of UK university graduates, we examine these issues using a Mincer-type framework, both in the short and in medium term after graduation. Our findings suggest that there is a persistent gap between Bohemian and non-Bohemians in terms of both the wages earned and employment status. This observation sharpens the need to better understanding the nature and extent of the externalities associated with the creative class which remains an unresolved issue

Application of imaging guidelines in patients with foreign body ingestion or inhalation: literature review

Ingestion, inhalation, and insertion of foreign bodies (FBs) are very common clinical occurrences. In any case, early diagnosis and prompt management are mandatory to avoid severe and life-threatening complications. Radiologists have an important role in revealing the presence, dimension, nature, and relationship with anatomical structures of a FB; selecting the most appropriate imaging modality; and enabling the best therapeutic choice. This review article focuses on the most frequent FBs ingested, inhaled, and inserted and presents the different tests and investigations to provide a correct radiological approach

Dynamic and quantitative evaluation of degenerative mitral valve disease: A dedicated framework based on cardiac magnetic resonance imaging

Background: Accurate quantification of mitral valve (MV) morphology and dynamic behavior over the cardiac cycle is crucial to understand the mechanisms of degenerative MV dysfunction and to guide the surgical intervention. Cardiac magnetic resonance (CMR) imaging has progressively been adopted to evaluate MV pathophysiology, although a dedicated framework is required to perform a quantitative assessment of the functional MV anatomy. Methods: We investigated MV dynamic behavior in subjects with normal MV anatomy (n=10) and patients referred to surgery due to degenerative MV prolapse, classified as fibro-elastic deficiency (FED, n=9) and Barlow's disease (BD, n=10). A CMR-dedicated framework was adopted to evaluate prolapse height and volume and quantitatively assess valvular morphology and papillary muscles (PAPs) function over the cardiac cycle. Multiple comparison was used to investigate the hallmarks associated to MV degenerative prolapse and evaluate the feasibility of anatomical and functional distinction between FED and BD phenotypes. Results: On average, annular dimensions were significantly (P < 0.05) larger in BD than in FED and normal subjects while no significant differences were noticed between FED and normal. MV eccentricity progressively decreased passing from normal to FED and BD, with the latter exhibiting a rounder annulus shape. Over the cardiac cycle, we noticed significant differences for BD during systole with an abnormal annular enlargement between mid and late systole (LS) (P < 0.001 vs. normal); the PAPs dynamics remained comparable in the three groups. Prolapse height and volume highlighted significant differences among normal, FED and BD valves. Conclusions: Our CMR-dedicated framework allows for the quantitative and dynamic evaluation of MV apparatus, with quantifiable annular alterations representing the primary hallmark of severe MV degeneration. This may aid surgeons in the evaluation of the severity of MV dysfunction and the selection of the appropriate MV treatment

Cardioplegia and angiotensin II receptor antagonists modulate signal transducers and activators of transcription activation in neonatal rat myocytes.

A crescente necessidade de informação para a tomada de decisões dos gestores do setor do transporte urbano de passageiros obriga a desenvolver sistemas para o cálculo, análise e controle de custos que permitam conhecer de forma acurada os mecanismos de formação dos seus preços internos. Nesse contexto, a medida do rendimento adquire um interesse especial quando é comparada a parâmetros e padrões significativos, que permitam aplicar técnicas de benchmarking para melhorar a gestão econômica do serviço. Com esses fins, entende-se que a geração de medidas representativas de padrões coletivos de comportamento constitui-se em uma ferramenta útil para orientar a ação de gestores e administradores públicos. E, como conseqüência, nós apresentamos à Asociación de Empresas de Transporte Urbano Colectivo (ATUC), na Espanha, um projeto para a criação de um Observatório de Custos que possa constituir-se em um importante ponto de referência para as empresas de transporte urbano de passageiros. Palavras-chave: Custos. Financiamento. Transporte urbano de passageiros. * Trabalho apresentado no XIII Congresso Brasileiro de Custos, realizado em Belo Horizonte – MG, no período de 30 de outubro a 01 de novembro 2006.The possibility of providing more complete and detailed data about passenger transport enterprises management justifies the development of analysis and cost control systems that provide precise and rigorous knowledge about internal price formation mechanisms. In this framework, measurement of performance is especially relevant when compared with some other significant reference parameters that allow the use of benchmarking in order to improve the economic management of the service. To this end, we consider it especially useful for the ATUC (Asociación de Empresas de Transporte Urbano Colectivo, i.e., the Association of Collective Urban Transport Companies) to provide a service that establishes measures which represent actual behaviour patterns, that enhances the knowledge of the reality of the sector and that generates a spirit of self-improvement in their associates. We presented a project to ATUC proposing the establishment of a Costs Observatory that can become a significant reference point for passenger transport companies. Key words: Costs. Funding. Urban Passenger Transport.Las crecientes necesidades de información para la gestión y la toma de decisiones de los agentes que operan en el sector del transporte urbano de pasajeros, obliga a desarrollar sistemas para el cálculo, análisis y control de costes que permitan un conocimiento riguroso de los mecanismos de formación de sus precios internos. En dicho marco, la medida del rendimiento adquiere especial interés cuando entra en comparación con parámetros y estándares significativos, que permitan aplicar técnicas de benchmarking para mejorar la gestión económica del servicio. A tales efectos, entendemos que la generación de medidas representativas de patrones colectivos de comportamiento, constituye una herramienta de gran utilidad para orientar la acción de gestores y administradores públicos. Y, en consecuencia, en España, y en el seno de la Asociación de Empresas de Transporte Urbano Colectivo (ATUC), estamos desarrollando un proyecto para la creación de un Observatorio de Costes que pueda constituirse en significativo punto de referencia para las empresas de transporte urbano de viajeros. Palabras clave: Costes. Financiación.Transporte urbano de viajeros

Efficacy of pulsatile flow perfusion in adult cardiac surgery: Hemodynamic energy and vascular reactivity

Background: The role of pulsatile (PP) versus non-pulsatile (NP) flow during a cardiopulmonary bypass (CPB) is still debated. This study’s aim was to analyze hemodynamic effects, endothelial reactivity and erythrocytes response during a CPB with PP or NP. Methods: Fifty-two patients undergoing an aortic valve replacement were prospectively randomized for surgery with either PP or NP flow. Pulsatility was evaluated in terms of energy equivalent pressure (EEP) and surplus hemodynamic energy (SHE). Systemic (SVRi) and pulmonary (PVRi) vascular resistances, endothelial markers levels and erythrocyte nitric-oxide synthase (eNOS) activity were collected at different perioperative time-points. Results: In the PP group, the resultant EEP was 7.3% higher than the mean arterial pressure (MAP), which corresponded to 5150 ± 2291 ergs/cm3 of SHE. In the NP group, the EEP and MAP were equal; no SHE was produced. The PP group showed lower SVRi during clamp-time (p = 0.06) and lower PVRi after protamine administration and during first postoperative hours (p = 0.02). Lower SVRi required a higher dosage of norepinephrine in the PP group (p = 0.02). Erythrocyte eNOS activity results were higher in the PP patients (p = 0.04). Renal function was better preserved in the PP group (p = 0.001), whereas other perioperative variables were comparable between the groups. Conclusions: A PP flow during a CPB results in significantly lower SVRi, PVRi and increased eNOS production. The clinical impact of increased perioperative vasopressor requirements in the PP group deserves further evaluation

Cardioplegia and angiotensin II receptor antagonists modulate signal transducers and activators of transcription activation in neonatal rat myocytes.

Previous investigations have shown that the signal transducers and activators of transcription (STATs) signaling pathway play an important role in the modulation of apoptosis after ischemia and reperfusion. The mechanism for this enhanced cardioprotection is unknown, but we believe that alterations STATs may play a role. To investigate this hypothesis, we examined the effects of angiotension II type 1 (AT1) and angiotension II type 2 (AT2) receptor antagonist added to cardioplegia on the downstream response of different STATs, connected with proinflammatory pathways (STAT2, STAT5) and prohypertrophic and antiapoptotic pathways (STAT3). Isolated, nonworking hearts (n = 3 per group) from neonatal rats were perfused aerobically (4°C) for 20 min in the Langendorff mode with the modified St. Thomas' Hospital no. 2 (MSTH2) cardioplegic solution (Group 1), the MSTH2 cardioplegic solution + AT1 receptor antagonist (Group 2), and MSTH2 cardioplegic solution + AT2 receptor antagonist (Group 3). Thus, myocytes were isolated by enzymatic digestion, and STAT2, STAT3, and STAT5 were investigated in Western blot studies. Times to arrest after cardioplegia were 8-12 s for all groups. Total cardioplegia delivery volume was about 300 mL for the 20 min. Perfusion with the MSTH2 cardioplegic solution supplemented with AT1 receptor antagonist (Group 2) induced a significant reduction in STAT2 and STAT5 tyrosine phosphorylation (-58 and -63%, respectively, vs. Group 1, P < 0.05). Conversely, STAT2 and STAT5 activation were unaffected by perfusion with the MSTH2 cardioplegic solution supplemented with AT2 receptor antagonist (Group 3). The decreased activation of STAT2 and STAT5 observed in Group 2 was accompanied by reduction of interleukin-1β (-57% in Group 2 vs. Group 1, P < 0.05). There were no significant differences in STAT3 phosphorylation among all groups. Only the addition of AT1 receptor antagonist to MSTH2 cardioplegia significantly decreases the inflammatory response of the neonatal rat cardiomyocytes without affecting antiapoptotic influence provided by tyrosine phosphorylation of STAT3. AT1 receptor antagonist added to cardioplegia represents an additional modality for enhancing myocardial protection during cardiac surgery and could contribute to optimize the ischemia tolerance of the pediatric heart

Investigation of plasmodiophora brassicae (clubroot disease) in vegetable brassica using arabidopsis thaliana as a model system

Clubroot, caused by Plasmodiophora brassicae, is the most devastating soil-borne disease of vegetable brassicas. It occurs all over the world and is responsible for crop losses of up to 10% every year. In Australia, the disease is being managed effectively with chemicals and cultural practices, but ideally control can be improved in the long term by the introduction of resistant cultivars. The life cycle ofP. brassicae and mode of action of plant resistance has not been fully elucidated because of the technical difficulties of working with an obligate, soil-borne plant pathogen. However, Arabidopsis thaliana, which is a host ofP. brassicae, has great potential as a model system for studying the life cycle, the infection process and development of resistance. We have developed a sand-liquid-culture system for growing Arabidopsis that allows easy observation of all life stages and, most importantly, the primary plasmodial stages within the root hair. The method was first optimised for observations of the lifecycle of the pathogen in a susceptible Arabidopsis ecotype (Col-3) where all stages of the lifecycle have now been observed and characterised. Further screening of Arabidopsis ecotypes for disease resistance has utilised one of the most virulent Australian pathotypes of brassica (ECD number 16/19/31). To date, Arabidopsis ecotype Ta-0 has shown a level of tolerance to the disease even though the roots get infected. It has been reported earlier that resistance toP. brassicae in Arabidopsis is due to one or a small number of genes. To examine changes in gene expression during the early, critical stages of infection, RNA was extracted from the susceptible and resistant ecotypes at two time points, 4 days and 17 days after inoculation. Microarray analysis will be used to investigate genome wide changes in gene expression during infection but also to identify candidate genes that may confer resistance to Australian isolates of the pathogen.<br /

Local hyperactivation of L-type Ca2+ channels increases spontaneous Ca2+ release activity and cellular hypertrophy in right ventricular myocytes from heart failure rats

Right ventricle (RV) dysfunction is an independent predictor of patient survival in heart failure (HF). However, the mechanisms of RV progression towards failing are not well understood. We studied cellular mechanisms of RV remodelling in a rat model of left ventricle myocardial infarction (MI)-caused HF. RV myocytes from HF rats show significant cellular hypertrophy accompanied with a disruption of transverse-axial tubular network and surface flattening. Functionally these cells exhibit higher contractility with lower Ca2+ transients. The structural changes in HF RV myocytes correlate with more frequent spontaneous Ca2+ release activity than in control RV myocytes. This is accompanied by hyperactivated L-type Ca2+ channels (LTCCs) located specifically in the T-tubules of HF RV myocytes. The increased open probability of tubular LTCCs and Ca2+ sparks activation is linked to protein kinase A-mediated channel phosphorylation that occurs locally in T-tubules. Thus, our approach revealed that alterations in RV myocytes in heart failure are specifically localized in microdomains. Our findings may indicate the development of compensatory, though potentially arrhythmogenic, RV remodelling in the setting of LV failure. These data will foster better understanding of mechanisms of heart failure and it could promote an optimized treatment of patients

Local hyperactivation of L-type Ca2+ channels increases spontaneous Ca2+ release activity and cellular hypertrophy in right ventricular myocytes from heart failure rats

Right ventricle (RV) dysfunction is an independent predictor of patient survival in heart failure (HF). However, the mechanisms of RV progression towards failing are not well understood. We studied cellular mechanisms of RV remodelling in a rat model of left ventricle myocardial infarction (MI)-caused HF. RV myocytes from HF rats show significant cellular hypertrophy accompanied with a disruption of transverse-axial tubular network and surface flattening. Functionally these cells exhibit higher contractility with lower Ca2+ transients. The structural changes in HF RV myocytes correlate with more frequent spontaneous Ca2+ release activity than in control RV myocytes. This is accompanied by hyperactivated L-type Ca2+ channels (LTCCs) located specifically in the T-tubules of HF RV myocytes. The increased open probability of tubular LTCCs and Ca2+ sparks activation is linked to protein kinase A-mediated channel phosphorylation that occurs locally in T-tubules. Thus, our approach revealed that alterations in RV myocytes in heart failure are specifically localized in microdomains. Our findings may indicate the development of compensatory, though potentially arrhythmogenic, RV remodelling in the setting of LV failure. These data will foster better understanding of mechanisms of heart failure and it could promote an optimized treatment of patients