RCAAP Repository

Pierce s Disease (PD) of grapevines is caused by the bacterium Xylella fastidiosa (Xf), a xylem-limited gamma-proteobacterium that is responsible for several economically important diseases in many plants. A characteristic symptom of PD is leaf scorching, with regions of chlorosis progressing into necrotic zones at the peripheral margins of infected leaves. The occlusion of xylem elements and interference with water transport by Xf and its associated biofilm have been hypothesized as the main cause of PD symptom development; however, Xf virulence mechanism has not been elucidated. The analysis of Xf Temecula 1 secretome revealed a putative lipase/esterase (PD1703) that was abundantly secreted in the bacterial culture supernatant, and was characterized as a protein ortholog of the cell wall degrading enzyme LipA of Xanthomonas strains. The LipA was secreted and associated with a biofilm filamentous network and additional proteomic analysis revealed its abundant presence in outer membrane vesicles (OMVs). Accumulation of LipA in leaf regions was positively associated with PD symptoms and inversely correlated with bacterial titer. The lipase/esterase was found to elicit a hypersensitive response in grapevine and was regulated by quorum-sensing signaling, which is known to modulate bacterial pathogenesis. We propose that Xff pathogenesis is caused by LipA secretion mediated by OMV cargos, and its release and accumulation in leaf margins leads to the observed PD symptoms development.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Conselho Nacional de Desenvolvimento Científico e Tecnológico

CHAPTER II: Objective: To evaluate the influence of age on the relationships between biochemical and hematological variables and stability of erythrocyte membrane in relation to the sodium dodecyl sulfate (SDS) in population of 105 female volunteers between 20 and 90 years. Methods: The stability of RBC membrane was determined by non-linear regression of the dependency of the absorbance of hemoglobin released as a function of SDS concentration, represented by the half-transition point of the curve (D50) and the variation in the concentration of the detergent to promote lysis (dD). Results: There was an age-dependent increase in the membrane stability in relation to SDS. Analyses by multiple linear regression showed that this stability increase is significantly related to the hematological variable red cell distribution width (RDW) and the biochemical variables blood albumin and cholesterol. Discussion: The positive association between erythrocyte stability and RDW may reflect one possible mechanism involved in the clinical meaning of this hematological index. CHAPTER III: Objective: To associate the morphological characteristics of erythrocytes obtained by atomic force microscopy (AFM) with its membrane stability and biochemical and hematological parameters in volunteers between 20 and 90 years. Methods: Contact-mode AFM provided arithmetic mean roughness (Ra), maximum height (Rz), average height (Rp) and average depth (Rv) of the cell membrane, as well as width, height and depth of the erythrocyte image. The sigmoidal curve of hemolysis by sodium dodecyl sulfate (SDS) was used to obtain the stability variables given by the half-transition point (D50) and the variation in the SDS (dD) concentration necessary to promote complete hemolysis of the blood samples. The microscopy and stability data were correlated with hematological and biochemical variables and antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) of each volunteer. Results: The values of Ra were lower in the group of older volunteers and presented inverse correlations with D50 and non-HDL- and total cholesterol. The Cat activity presented an inverse correlation with Amax, triglycerides and VLDL-cholesterol, while the SOD activity exhibited a direct correlation with the erythrocyte width. Discussion: The smaller values of Ra found in the older volunteers erythrocytes may be related to the membrane changes caused by high values of blood cholesterol and decreased activities of antioxidant enzymes.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

In the present study, five analogue herbicides, namely Imazapyr (IMZR), Imazapic (IMZC), Imazethapyr (IMZT), Imazamox (IMZX) and Imazaquin (IMZQ), were evaluated for genotoxicity (mutagenic and recombinagenic activity) in the wing somatic mutation and recombination test (SMART) of Drosophila melanogaster. They are classified as imidazolinone (IMI) pesticides and their mode of action is to inhibit acetohydroxyacid synthesis (AHAS) an enzyme involved with the biosynthesis of the amino acids leucine, isoleucine and valine. For this purpose, two crosses were used: the standard (ST) cross and the high-bioactivation (HB) cross. The latter is characterized by high CYP450-dependent activation capacity awarding increased sensitivity to promutagens and procarcinogens. Three-day-old larvae were exposed to chronic feeding (48 h) to four different concentrations of these herbicides (2.5; 5.0; 10.0 and 20.0 mM). For the evaluation of genotoxic effects, the frequencies of spots per individual in the treated series were compared to the concurrent negative control series (ultra pure water). In the ST-cross, imazamox showed positive result only for large single spots (20.0 mM IMZX) and weak positive results for total spots (10.0 and 20.0 mM IMZX), while Imazaquin showed positive results only for large single spots (5.0 and 20.0 mM IMZQ) and a weak positive result for total spots (20.0 mM IMZQ). In the HB-cross, only Imazamox (5.0 mM IMZX) showed a weak positive result for small single spots, what suggest the involvement of CH2OCH3 radical and quinolinic ring in the genotoxicity, respectively, of Imazamox and Imazaquin herbicides. Imazapyr, Imazapic and Imazethapyr gave negative results with both crosses of the wing spot test. The positive control urethane caused an increase in the number of all types of spots in both ST- and HB- crosses. In conclusion, the results of chronic treatments performed at high doses (toxicity was observed at higher doses) indicate that, under these experimental conditions, the few positive results observed suggest the involvement of CH2OCH3 radical and quinolinic ring in the genotoxicity, respectively, of Imazamox and Imazaquin herbicides and the involvement of CYP450 enzymes in IMI herbicide detoxification. Nevertheless, further research is needed to discern the genotoxic potential of IMI herbicides active ingredients and their formulations and the involvement of CH2OCH3 radical and quinolinic ring in the genotoxicity of Imazamox and Imazaquin herbicides.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

This work evaluated the reaction of 140 corn hybrids from double-haploid inbred derived from a crossing of a resistant inbred line with and susceptible inbred line. Being that, crossed with a conventional susceptible line which were inoculated with Stenocarpella maydis and Stenocarpella macrospora .The hybrids were assessed in three locations in the Miner Triangle and three locations in Southern Brazil to evaluate the difference of hybrids reaction to S. macrospora and S. maydis. Two analysis were performed, one of the three locations in the Miner Triangle and one of the three locations in the South for the separation of five resistant hybrids, five average resistance and five susceptible to rot grain for the two locations. About the incidence of rot grain obtained from the hybrids, the quantification of S. macrospora, S.maydis and other fungi were done in the laboratory for the Miner Triangle and South of Brazil. In a joint analysis in the Miner Triangle it was found a frequency of 60% S. macrospora, 10% S.maydis and 30% other fungi. And in a joint analysis of South Brazil found 20% S. macrospora, 11% S.maydis and 69% of other fungi. The pathogen hybrid interaction showed the prevalence of S. macrospora in incidence of infected grains, with 60% in the Miner Triangle and 20% in the South, against S. maydis with 10% in the Miner Triangle and 11% in south of Brazil. These results showed that there were differences between the two places regarding the rotten grain caused by S. macrospora and S. maydis. Thus, positioning breeding programs in the pathosystem Stenocarpella-corn.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The Epstein Barr virus (EBV) is studied in this project to establish a latency compared with the infected organism and to a number of pathophysiologies. Its oncogenic potential associated with serological evidence of the presence of the viral agent for cancer and also for autoimmune diseases such as rheumatoid arthritis and lupus erythematosus. Detection processes are necessary and have attracted scientific interest in recent decades, and they are important analytical tools used for clinical diagnosis, disease control, physiological changes, among others. Through the above two genosensors were developed to the specific recognition of EBV by electrochemistry. The peak oxidation of ethidium bromide (EB) in graphite electrodes modified with poly (4-ATP) and the peak tetramethylbenzindine (TMB) reduction, as a new indicator of hybridization oligonucleides, in graphite electrodes modified with poly (AP-4) were designed and evaluated these platforms. Analysis of Surface Plasmon Resonance (SPR) and Atomic Force Microscopy (AFM) were used to complement the study to theoretical and practical application. The prospect of this project is the application in the diagnosis of infection caused by the Epstein-Barr virus (in serum samples, saliva and urine) non-invasively in rapid tests evaluating their sensitivity, selectivity, specificity, speed and low cost.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

The population with obesity has grown in Brazil in the last few decades, including adolescents. Among the most successful strategies for its treatment is multidisciplinary intervention. Thus, the objective of this thesis was to try and understand the effects of multidisciplinary treatment on markers of inflammation and oxidative stress in obese adolescents. Were selected obese adolescents to participate in a multidisciplinary treatment which was attended by doctors, nutritionists, physiotherapists, psychologists and physical educators. The program has a duration of 10 months and were evaluated, in addition to anthropometric parameters and physical performance, the markers of inflammation and oxidative stress. Were produced, with the data collection, two studies. The first a longitudinal study, where were observed improvements in inflammatory parameters and reduction of oxidative stress with the multidisciplinary treatment, in addition to a reduction in the anthropometric parameters related to obesity. The second, a cross-sectional study has identified the association between inflammatory state and cardiorespiratory fitness in obese adolescents, indicating that a good cardiorespiratory capacity reduces, regardless of the level of obesity, the consequences caused by chronic inflammation. These two studies can be read in detail in the chapters of this thesis. In general, we conclude that the multiprofessional treatment is able to promote positive changes in markers of inflammation and oxidative stress in obese adolescents.