861 resultados para Discourse Markers


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this work was to identify genes that could be used as suitable markers for molecular recognition of phenological stages during coffee (Coffea arabica) fruit development. Four cultivars were evaluated as to their differential expression of genes associated to fruit development and maturation processes. Gene expression was characterized by both semi-quantitative and quantitative RT-PCR, in fruit harvested at seven different developmental stages, during three different seasons. No size polymorphisms or differential expression were observed among the cultivars for the evaluated genes; however, distinct expression profiles along fruit development were determined for each gene. Four out of the 28 evaluated genes exhibited a regular expression profile in all cultivars and harvest seasons, and, therefore, they were validated as candidate phenological markers of coffee fruit. The gene α-galactosidase can be used as a marker of green stage, caffeine synthase as a marker of transition to green and yellowish-green stages, and isocitrate lyase and ethylene receptor 3 as markers of late maturation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this work was to evaluate the efficiency of EST‑SSR markers in the assessment of the genetic diversity of rubber tree genotypes (Hevea brasiliensis) and to verify the transferability of these markers for wild species of Hevea. Forty‑five rubber tree accessions from the Instituto Agronômico (Campinas, SP, Brazil) and six wild species were used. Information provided by modified Roger's genetic distance were used to analyze EST‑SSR data. UPGMA clustering divided the samples into two major groups with high genetic differentiation, while the software Structure distributed the 51 clones into eight groups. A parallel could be established between both clustering analyses. The 30 polymorphic EST‑SSRs showed from two to ten alleles and were efficient in amplifying the six wild species. Functional EST‑SSR microsatellites are efficient in evaluating the genetic diversity among rubber tree clones and can be used to translate the genetic differences among cultivars and to fingerprint closely related materials. The accessions from the Instituto Agronômico show high genetic diversity. The EST‑SSR markers, developed from Hevea brasiliensis, show transferability and are able to amplify other species of Hevea.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this work was to evaluate the diversity and genetic relationships between lines and varieties of the sweet sorghum (Sorghum bicolor) germplasm bank of the National Institute for Forestry, Agriculture and Livestock Research, Mexico, using AFLP and SSR markers. The molecular markers revealed robust amplification profiles and were able to differentiate the 41 genotypes of sweet sorghum evaluated. Analysis of the frequency and distribution of polymorphic fragments allowed for the detection of unique (AFLP) and rare (SSR) alleles in several genotypes (RBSS‑8, RBSS‑9, RBSS‑25, RBSS‑32, and RBSS‑37), indicating that these markers may be associated with a feature that has not yet been determined or may be useful for the identification of these genotypes. The genetic relationships indicated the presence of at least two types of sweet sorghum: a group of modern genotypes used for sugar and biofuel production, and another group consisting of historic and modern genotypes used for the production of syrups. Sweet sorghum genotypes may be used to develop new varieties with higher sugar and juice contents.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this work was to standardize a semiautomated method for genotyping soybean, based on universal tail sequence primers (UTSP), and to compare it with the conventional genotyping method that uses electrophoresis in polyacrylamide gels. Thirty soybean cultivars were genotypically characterized by both methods, using 13 microsatellite loci. For the UTSP method, the number of alleles (NA) was 50 (2-7 per marker) and the polymorphic information content (PIC) ranged from 0.40 to 0.74. For the conventional method, the NA was 38 (2-5 per marker) and the PIC varied from 0.39 to 0.67. The genetic dissimilarity matrices obtained by the two methods were highly correlated with each other (0.8026), and the formed groups were coherent with the phenotypic data used for varietal registration. The 13 markers allowed the distinction of all analyzed cultivars. The low cost of the UTSP method, associated with its high accuracy, makes it ideal for the characterization of soybean cultivars and for the determination of genetic purity.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Objective: To assess the effectiveness of obesity markers to detect high (>5%) 10- year risk of fatal cardiovascular disease (CVD) as estimated using the SCORE function. Methods: Cross-sectional study including 3,047 women and 2,689 men aged 35-75 years (CoLaus study). Body fat percentage was assessed by tetrapolar bioimpedance. CVD risk was assessed using the SCORE risk function and gender and age-specific cut points for body fat were derived. The diagnostic accuracy of each obesity marker was evaluated through receiver operating characteristics (ROC) analysis. Results: Body fat presented a higher correlation with 10-year CVD risk than waist/hip ratio (WHR), waist or BMI: in men, r=0.31, 0.22, 0.19 and 0.12 and for body fat, WHR, waist and BMI, respectively; the corresponding values in women were 0.18, 0.15, 0.11 and 0.05, respectively (all p<0.05). In both genders, body fat showed the highest area under the ROC curve (AUC): in men, the AUC (and 95% confidence interval) were 76.0 (73.8 - 78.2), 67.3 (64.6 - 69.9), 65.8 (63.1 - 68.5) and 60.6 (57.9 - 63.5) for body fat, WHR, waist and BMI, respectively. In women, the corresponding values were 72.3 (69.2 - 75.3), 66.6 (63.1 - 70.2), 64.1 (60.6 - 67.6) and 58.8 (55.2 - 62.4). The use of body fat percentage criterion enabled to capture three times more subjects with high CVD risk than BMI criterion, and almost twice as much as WHR criterion.. Conclusions: Obesity defined by body fat percentage is more accurate to detect high 10-year risk of fatal CVD than obesity markers based on WHR, waist or BMI.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Electroencephalography (EEG) is an easily accessible and low-cost modality that might prove to be a particularly powerful tool for the identification of subtle functional changes preceding structural or metabolic deficits in progressive mild cognitive impairment (PMCI). Most previous contributions in this field assessed quantitative EEG differences between healthy controls, MCI and Alzheimer's disease(AD) cases leading to contradictory data. In terms of MCI conversion to AD, certain longitudinal studies proposed various quantitative EEG parameters for an a priori distinction between PMCI and stable MCI. However, cross-sectional comparisons revealed a substantial overlap in these parameters between MCI patients and elderly controls. Methodological differences including variable clinical definition of MCI cases and substantial interindividual differences within the MCI group could partly explain these discrepancies. Most importantly, EEG measurements without cognitive demand in both cross-sectional and longitudinal designs have demonstrated limited sensitivity and generally do not produce significant group differences in spectral EEG parameters. Since the evolution of AD is characterized by the progressive loss of functional connectivity within neocortical association areas, event-modulated EEG dynamic analysis which makes it possible to investigate the functional activation of neocortical circuits may represent a more sensitive method to identify early alterations of neuronal networks predictive of AD development among MCI cases. The present review summarizes clinically significant results of EEG activation studies in this field and discusses future perspectives of research aiming to reach an early and individual prediction of cognitive decline in healthy elderly controls.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Työn tarkoituksena oli tutkia sisältö- ja diskurssianalyysin avulla kuinka yritykset viestivät asiakasreferenssejä verkkosivuillaan. Työssä keskityttiin tutkimaan yritysten referenssikuvausten teemoja ja diskursseja, sekä sitä kuinka referenssisuhde rakentuu diskursiivisesti referenssikuvauksissa. Tutkimukseen valittiin kolme suomalaista ICT-alan yritystä: Nokia, TietoEnator ja F-Secure. Aineisto koostuu 140:stä yritysten WWW-sivuilta kerätystä referenssikuvauksesta. Sisältöanalyysin tuloksena havaittiin, että referenssikuvaukset keskittyvät kuvaamaan yksittäisiä tuote- tai projektitoimituksia referenssiasiakkaille kyseisten asiakassuhteiden valossa. Analyysin tuloksena tunnistettiin kolme diskurssia: hyötydiskurssi, sitoutumisen diskurssi sekä teknologisen eksperttiyden diskurssi. Diskurssit paljastavat referenssikuvausten retoriset keinot ja konstruoivat referenssisuhteen ja toimittajan subjektiposition eri näkökulmista. Pääpaino referenssikuvauksissa on toimittajan ratkaisun tuomissa hyödyissä. Diskurssit tuottavat referenssisuhteesta kuvan hyötyjä tuovana ja läheisenä asiakassuhteena, joka tarjoaa väylän ulkopuolisiin kyvykkyyksiin ja teknologioihin. Toimittaja esitetään referenssikuvauksissa diskurssista riippuen hyötyjen tuojana, luotettavana partnerina sekä kokeneena eksperttinä. Referenssiasiakas sen sijaan esitetään vain yhdestä näkökulmasta stereotyyppisesti tärkeänä ja tyytyväisenä asiakkaana.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Dimethylarginine and homocysteine metabolism are closely linked and alterations of both were observed in plasma and cerebrospinal fluid (CSF) of patients with Alzheimer's disease (AD). CSF parameters of homocysteine metabolism have recently been found to be associated with the CSF level of the AD biomarker phosphorylated tau (ptau) in AD patients. To investigate possible relationships between homocysteine and dimethylarginine metabolism and the AD CSF biomarkers ptau181 and amyloid-β 1-42 (Aβ42), we assessed parameters of homocysteine metabolism (CSF homocysteine, S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), 5-methyltetrahydrofolate (5-MTHF)) and dimethylarginine metabolism (plasma and CSF asymmetric dimethylarginine (ADMA), symmetric dimethylarginine, L-arginine) as well as CSF Aβ42 and ptau181 in 98 controls and 51 AD patients. Multivariate linear regression analyses were performed to assess associations between the considered parameters. SAH concentrations show significant associations to CSF ADMA levels, and CSF ADMA and L-arginine to ptau181, but not to Aβ42 concentrations in AD patients. When including concentrations of homocysteine, 5-MTHF, SAM, and SAH into the analysis, CSF ADMA concentrations independently predicted ptau181 levels in AD patients but homocysteine-related metabolites were associated with ptau181 only when ADMA was removed from the analysis model. These results suggest that CSF ADMA may interact with CNS homocysteine metabolism and may contribute to neurodegeneration and accumulation of phosphorylated tau in AD. Functional and interventional studies are needed to further proof this hypothesis.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Abstract: The objective of this work was to identify polymorphic simple sequence repeat (SSR) markers for varietal identification of cotton and evaluation of the genetic distance among the varieties. Initially, 92 SSR markers were genotyped in 20 Brazilian cotton cultivars. Of this total, 38 loci were polymorphic, two of which were amplified by one primer pair; the mean number of alleles per locus was 2.2. The values of polymorphic information content (PIC) and discrimination power (DP) were, on average, 0.374 and 0.433, respectively. The mean genetic distance was 0.397 (minimum of 0.092 and maximum of 0.641). A panel of 96 varieties originating from different regions of the world was assessed by 21 polymorphic loci derived from 17 selected primer pairs. Among these varieties, the mean genetic distance was 0.387 (minimum of 0 and maximum of 0.786). The dendrograms generated by the unweighted pair group method with arithmetic average (UPGMA) did not reflect the regions of Brazil (20 genotypes) or around the world (96 genotypes), where the varieties or lines were selected. Bootstrap resampling shows that genotype identification is viable with 19 loci. The polymorphic markers evaluated are useful to perform varietal identification in a large panel of cotton varieties and may be applied in studies of the species diversity.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The low 137Cs activity observed in marine sediments of tropical regions often precludes its use as chronostratigraphic marker. Here we present a study on the use of Pu and Am radioisotopes as alternative markers to constrain the 210Pb ages in a sediment core of the Havana Bay (Cuba). Mean activity ratios of 238Pu/239,240Pu, 241Am/239,240Pu and 241Pu/239,240Pu indicated that the nuclear weapon tests fallout is the main source of the anthropogenic radionuclides. While the inventory of 137Cs in the sediments is lower than the expected fallout inventory, 239,240Pu accumulates in the sediments with inventories higher than the expected fallout inventory. The high fluxes of 239,240Pu are nevertheless corroborated here through use of 210Pb, and confirm that focusing of solid particles is of great importance in the investigated site. 239,240Pu showed to be a useful time tracer in marine sites where the 137Cs signal is very low.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Summary: Particulate air pollution is associated with increased cardiovascular risk. The induction of systemic inflammation following particle inhalation represents a plausible mechanistic pathway. The purpose of this study was to assess the associations of short-term exposure to ambient particulate matters of aerodynamic diameter less than 10 μm (PM10) with circulating inflammatory markers in 6183 adults in Lausanne, Switzerland. The results show that short-term exposure to PM10 was associated with higher levels of circulating IL-6 and TNF-α. The positive association of PM10 with markers of systemic inflammation materializes the link between air pollution and cardiovascular risk. Background: Variations in short-term exposure to particulate matters (PM) have been repeatedly associated with daily all-cause mortality. Particle-induced inflammation has been postulated to be one of the important mechanisms for increased cardiovascular risk. Experimental in-vitro, in-vivo and controlled human studies suggest that interleukin 6 (IL-6) and tumor-necrosis-factor alpha (TNF-α) could represent key mediators of the inflammatory response to PM. The associations of short-term exposure to ambient PM with circulating inflammatory markers have been inconsistent in studies including specific subgroups so far. The epidemiological evidence linking short-term exposure to ambient PM and systemic inflammation in the general population is scarce. So far, large-scale population-based studies have not explored important inflammatory markers such as IL-6, IL-1β or TNF-α. We therefore analyzed the associations between short-term exposure to ambient PM10 and circulating levels of high-sensitive CRP (hs-CRP), IL-6, IL-1β and TNF-α in the population-based CoLaus study. Objectives: To assess the associations of short-term exposure to ambient particulate matters of aerodynamic diameter less than 10 μm (PM10) with circulating inflammatory markers, including hs-CRP, IL-6, IL-1β and TNF-α, in adults aged 35 to 75 years from the general population. Methodology: All study subjects were participants to the CoLaus study (www.colaus.ch) and the baseline examination was carried out from 2003 to 2006. Overall, 6184 participants were included. For the present analysis, 6183 participants had data on at least one of the four measured circulating inflammatory markers. The monitoring data was obtained from the website of Swiss National Air Pollution Monitoring Network (NABEL). We analyzed data on PM10 as well as outside air temperature, pressure and humidity. Hourly concentrations of PM10 were collected from 1 January 2003 to 31 December 2006. Robust linear regression (PROC ROBUSTREG) was used to evaluate the relationship between cytokine inflammatory and PM10. We adjusted all analyses for age, sex, body mass index, smoking status, alcohol consumption, diabetes status, hypertension status, education levels, zip code, and statin intake. All data were adjusted for the effects of weather by including temperature, barometric pressure, and season as covariates in the adjusted models. We performed simple and multiple logistic regression analyses. Descriptive statistical analysis used the Wilcoxon rank sum test (for medians). All data analyses were performed using SAS software (version 9.2; SAS Institute Inc., Cary, NC, USA), and a two-sided significance level of 5% was used. Results: PM10 levels averaged over 24 hours were significantly and positively associated with continuous IL-6 and TNF-α levels, in the whole study population both in unadjusted and adjusted analyses. For each cytokine, there was a similar seasonal pattern, with wider confidence intervals in summer than during the other seasons, which might partly be due to the smaller number of participants examined in summer. The associations of PM10 with IL-6 and TNF-α were also found after having dichotomized these cytokines into high versus low levels, which suggests that the associations of PM10 with the continuous cytokine levels are very robust to any distributional assumption and to potential outlier values. In contrast with what we observed for continuous IL-1β levels, high PM10 levels were significantly associated with high IL-1β. PM10 was significantly associated with IL-6 and TNF-α in men, but with TNF-α only in women. However, there was no significant statistical interaction between PM10 and sex. For IL-6 and TNF-α, the associations tended to be stronger in younger people, with a significant interaction between PM10 and age groups for IL-6. PM10 was significantly associated with IL-6 and TNF-α in the healthy group and also in the "non-healthy" group, although the statistical interaction between healthy status and PM10 was not significant. Conclusion: In summary, we found significant independent positive associations of short-term exposure to PM10 with circulating levels of IL-6 and TNF-α in the adult population of Lausanne. Our findings strongly support the idea that short-term exposure to PM10 is sufficient to induce systemic inflammation on a broad scale in the general population. From a public health perspective, the reported association of elevated inflammatory cytokines with short-term exposure to PM10 in a city with relatively clean air such as Lausanne supports the importance of limiting urban air pollution levels.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

BACKGROUND: Data regarding immunomodulatory effects of parenteral n-3 fatty acids in sepsis are conflicting. In this study, the effect of administration of parenteral n-3 fatty acids on markers of brain injury, incidence of sepsis-associated delirium, and inflammatory mediators in septic patients was investigated. METHODS: Fifty patients with sepsis were randomized to receive either 2 ml/kg/day of a lipid emulsion containing highly refined fish oil (equivalent to n-3 fatty acids 0.12 mg/kg/day) during 7 days after admission to the intensive care unit or standard treatment. Markers of brain injury and inflammatory mediators were measured on days 1, 2, 3 and 7. Assessment for sepsis-associated delirium was performed daily. The primary outcome was the difference in S-100β from baseline to peak level between both the intervention and the control group, compared by t-test. Changes of all markers over time were explored in both groups, fitting a generalized estimating equations model. RESULTS: Mean difference in change of S-100β from baseline to peak level was 0.34 (95% CI: -0.18-0.85) between the intervention and control group, respectively (P = 0.19). We found no difference in plasma levels of S-100β, neuron-specific enolase, interleukin (IL)-6, IL-8, IL-10, and C-reactive protein between groups over time. Incidence of sepsis-associated delirium was 75% in the intervention and 71% in the control groups (risk difference 4%, 95% CI -24-31%, P = 0.796). CONCLUSION: Administration of n-3 fatty acids did not affect markers of brain injury, incidence of sepsis-associated delirium, and inflammatory mediators in septic patients.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Polyploidization, which is expected to trigger major genomic reorganizations, occurs much less commonly in animals than in plants, possibly because of constraints imposed by sex-determination systems. We investigated the origins and consequences of allopolyploidization in Palearctic green toads (Bufo viridis subgroup) from Central Asia, with three ploidy levels and different modes of genome transmission (sexual versus clonal), to (i) establish a topology for the reticulate phylogeny in a species-rich radiation involving several closely related lineages and (ii) explore processes of genomic reorganization that may follow polyploidization. Sibship analyses based on 30 cross-amplifying microsatellite markers substantiated the maternal origins and revealed the paternal origins and relationships of subgenomes in allopolyploids. Analyses of the synteny of linkage groups identified three markers affected by translocation events, which occurred only within the paternally inherited subgenomes of allopolyploid toads and exclusively affected the linkage group that determines sex in several diploid species of the green toad radiation. Recombination rates did not differ between diploid and polyploid toad species, and were overall much reduced in males, independent of linkage group and ploidy levels. Clonally transmitted subgenomes in allotriploid toads provided support for strong genetic drift, presumably resulting from recombination arrest. The Palearctic green toad radiation seems to offer unique opportunities to investigate the consequences of polyploidization and clonal transmission on the dynamics of genomes in vertebrates.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

It has been evaluated the genetic variability through the use of RAPD molecular markers on the following passionflower species: Passiflora amethystina, P. caerulea, P. cincinnata, P. coccinea, P. serrato digitata, P. foetida, P. maliformis, P. alata, P. giberti, P. laurifolia, P. macrocarpa, P. nitida, P. setacea, P. suberosa, P. ligularis, P. capsularis, P. edulis Sims and its botanical variety P. edulis Sims f. flavicarpa Deg. In this research work, the analyses of the random amplified polymorphic DNA products (RAPD) were employed to estimate the genetic diversity and the taxonomic linkage within the species above. The total of 21 primers were used in this study which generated 270 different polymorphic products. It was possible to detect that the Passiflora species had shown a similarity of 17,3%, and between Passiflora edulis Sims and Passiflora edulis Sims f. flavicarpa a similarity of 34,35% has been found. The rate of similarity within edulis specie is low, making it clear that a large variability between the yellow and the purple forms exists.