133 research outputs found

    Does Constitutive Expression of Defense-Related Genes and Salicylic Acid Concentrations Correlate with Field Resistance of Potato to Black Scurf Disease?

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    Black scurf disease on potato caused by Rhizoctonia solani AG3 occurs worldwide and is difficult to control. The use of potato cultivars resistant to black scurf disease could be part of an integrated control strategy. Currently, the degree of resistance is based on symptom assessment in the field, but molecular measures could provide a more efficient screening method. We hypothesized that the degree of field resistance to black scurf disease in potato cultivars is associated with defense-related gene expression levels and salicylic acid (SA) concentration. Cultivars with a moderate and severe appearance of disease symptoms on tubers were selected and cultivated in the same field. In addition, experiments were conducted under controlled conditions in an axenic in vitro culture and in a sand culture to analyze the constitutive expression of defense-related genes and SA concentration. The more resistant cultivars did not show significantly higher constitutive expression levels of defense-related genes. Moreover, the level of free SA was increased in the more resistant cultivars only in the roots of the plantlets grown in the sand culture. These results indicate that neither expression levels of defense-related genes nor the amount of SA in potato plants can be used as reliable predictors of the field resistance of potato genotypes to black scurf disease

    Calcium‐dependent protein kinase 5 links calcium signaling with N‐hydroxy‐l‐pipecolic acid‐ and SARD1‐dependent immune memory in systemic acquired resistance

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    Systemic acquired resistance (SAR) prepares infected plants for faster and stronger defense activation upon subsequent attacks. SAR requires an information relay from primary infection to distal tissue and the initiation and maintenance of a self‐maintaining phytohormone salicylic acid (SA)‐defense loop. In spatial and temporal resolution, we show that calcium‐dependent protein kinase CPK5 contributes to immunity and SAR. In local basal resistance, CPK5 functions upstream of SA synthesis, perception, and signaling. In systemic tissue, CPK5 signaling leads to accumulation of SAR‐inducing metabolite N‐hydroxy‐L‐pipecolic acid (NHP) and SAR marker genes, including Systemic Acquired Resistance Deficient 1 (SARD1) Plants of increased CPK5, but not CPK6, signaling display an ‘enhanced SAR’ phenotype towards a secondary bacterial infection. In the sard1‐1 background, CPK5‐mediated basal resistance is still mounted, but NHP concentration is reduced and enhanced SAR is lost. The biochemical analysis estimated CPK5 half maximal kinase activity for calcium, K50 [Ca2+], to be c. 100 nM, close to the cytoplasmic resting level. This low threshold uniquely qualifies CPK5 to decode subtle changes in calcium, a prerequisite to signal relay and onset and maintenance of priming at later time points in distal tissue. Our data explain why CPK5 functions as a hub in basal and systemic plant immunity

    Plant Immune Memory in Systemic Tissue Does Not Involve Changes in Rapid Calcium Signaling

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    Upon pathogen recognition, a transient rise in cytoplasmic calcium levels is one of the earliest events in plants and a prerequisite for defense initiation and signal propagation from a local site to systemic plant tissues. However, it is unclear if calcium signaling differs in the context of priming: Do plants exposed to a first pathogen stimulus and have consequently established systemic acquired resistance (SAR) display altered calcium responses to a second pathogen stimulus? Several calcium indicator systems including aequorin, YC3.6 or R-GECO1 have been used to document local calcium responses to the bacterial flg22 peptide but systemic calcium imaging within a single plant remains a technical challenge. Here, we report on an experimental approach to monitor flg22-induced calcium responses in systemic leaves of primed plants. The calcium-dependent protein kinase CPK5 is a key calcium sensor and regulator of the NADPH oxidase RBOHD and plays a role in the systemic calcium-ROS signal propagation. We therefore compared flg22-induced cytoplasmic calcium changes in Arabidopsis wild-type, cpk5 mutant and CPK5-overexpressing plants (exhibiting constitutive priming) by introgressing the calcium indicator R-GECO1-mTurquoise that allows internal normalization through mTurquoise fluorescence. Aequorin-based analyses were included for comparison. Based on the R-GECO1-mTurquoise data, CPK5-OE appears to reinforce an “oscillatory-like” Ca2+ signature in flg22-treated local tissues. However, no change was observed in the flg22-induced calcium response in the systemic tissues of plants that had been pre-challenged by a priming stimulus – neither in wild-type nor in cpk5 or CPK5-OE-lines. These data indicate that the mechanistic manifestation of a plant immune memory in distal plant parts required for enhanced pathogen resistance does not include changes in rapid calcium signaling upstream of CPK5 but rather relies on downstream defense responses

    Accounting for frailty and multimorbidity when interpreting high-sensitivity troponin I tests in oldest old

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    Background Older patients evaluated in Emergency Departments (ED) for suspect Myocardial Infarction (MI) frequently exhibit unspecific elevations of serum high-sensitivity troponin I (hs-TnI), making interpretation particularly challenging for emergency physicians. The aim of this longitudinal study was to identify the interaction of multimorbidity and frailty with hs-TnI levels in older patients seeking emergency care. Methods A group of patients aged≥75 with suspected MI was enrolled in our acute geriatric ward immediately after ED visit. Multimorbidity and frailty were measured with Cumulative Illness Rating Scale (CIRS) and Clinical Frailty Scale (CFS), respectively. The association of hs-TnI with MI (main endpoint) was assessed by calculation of the Area Under the Receiver-Operating Characteristic Curve (AUROC), deriving population-specific cut-offs with Youden test. The factors associated with hs-TnI categories, including MI, CFS and CIRS, were determined with stepwise multinomial logistic regression. The association of hs-TnI with 3-month mortality (secondary endpoint) was also investigated with stepwise logistic regression. Results Among 268 participants (147 F, median age 85, IQR 80–89), hs-TnI elevation was found in 191 cases (71%, median 23 ng/L, IQR 11–65), but MI was present in only 12 cases (4.5%). hs-TnI was significantly associated with MI (AUROC 0.751, 95% CI 0.580–0.922, p = 0.003), with an optimal cut-off of 141 ng/L. hs-TnI levels ≥141 ng/L were significantly associated with CFS (OR 1.58, 95% CI 1.15–2.18, p = 0.005), while levels <141 ng/L were associated with the cardiac subscore of CIRS (OR 1.36, 95% CI 1.07–1.71, p = 0.011). CFS, but not hs-TnI levels, predicted 3-month mortality. Conclusions In geriatric patients with suspected MI, frailty and cardiovascular multimorbidity should be carefully considered when interpreting emergency hs-TnI testing

    Synchrotron Emission from Hot Accretion Flows and the Cosmic Microwave Background Anisotropy

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    Current estimates of number counts of radio sources in the frequency range where the most sensitive Cosmic Microwave Background (CMB) experiments are carried out significantly under-represent sources with strongly inverted spectra. Hot accretion flows around supermassive black holes in the nuclei of nearby galaxies are expected to produce inverted radio spectra by thermal synchrotron emission. We calculate the temperature fluctuations and power spectra of these sources in the Planck Surveyor 30 GHz energy channel, where their emission is expected to peak. We find that their potential contribution is generally comparable to the instrumental noise, and approaches the CMB anisotropy level at small angular scales. Forthcoming CMB missions, which will provide a large statistical sample of inverted-spectra sources, will be crucial for determining the distribution of hot accretion flows in nearby quiescent galactic nuclei. Detection of these sources in different frequency channels will help constrain their spectral characteristics, hence their physical properties.Comment: 10 pages, 4 figures, accepted for publication in Ap

    Implementing a multidisciplinary rapid geriatric observation unit for non-critical older patients referred to hospital: observational study on real-world data

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    Background: Geriatric rapid observation units may represent an alternative to hospitalization in older patients with non-critical acute illness. Aims: To describe the characteristics and outcomes of patients admitted to a geriatric observation unit called URGe (UnitĂ  Geriatrica Rapida), implemented in an Italian hospital and characterized by multidisciplinary medical staff with geriatric expertise, fast-track access to diagnostic resources, regular use of point-of-care ultrasound and predicted length of stay (LOS) < 72 h. Methods: The medical records of patients admitted to URGe during a 3-month period (452 subjects, 247 F and 205 M, median age 82 years, IQR 77-87) were retrospectively examined. The primary study endpoint was transferral from URGe to regular wards. Baseline covariates included demographics, comprehensive geriatric assessment, acute illnesses, comorbidities, vital signs and routine laboratory tests. Results: Despite elevated burden of multimorbidity (median number of chronic diseases 4, IQR 2-5) and frailty (median Rockwood Clinical Frailty Scale score 4, IQR 3-6), only 137 patients (30.3%) required transferral from URGe to regular wards. The main factors positively associated with this outcome were Rockwood score, fever, cancer and red cell distribution width (P < 0.05 on multivariate logistic regression model). The rate of complications (mortality, delirium, and falls) during URGe stay was low (0.5%, 7% and 2%, respectively). Overall duration of hospital stay was lower than that of a group of historical controls matched by age, sex, main diagnosis, multimorbidity and frailty. Conclusions: The URGe model of acute geriatric care is feasible, safe and has the potential of reducing unnecessary hospitalizations of older patients

    Dietary habits in women with recurrent idiopathic calcium nephrolithiasis

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    Nutrition has been widely recognized to influence the risk of kidney stone formation. Therefore the aim of our study was to assess: a) whether usual diet of women with idiopathic calcium nephrolithiasis (ICN) living in Parma (Northern-Italy) is different compared to healthy controls, b) how their diet differs from Italian National guidelines and c) whether it is related to nephrolithiasis clinical course
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