182 resultados para nodule senescence

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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The anatomy and ultrastructure of root nodules of Anadenanthera peregrina var. falcata (Leguminosae-Mimosoideae) were analysed, as was plant growth. To ensure that nodules developed, seedlings were inoculated with a mixture of six strains of rhizobia. Nodules were produced that differed in appearance-and probably also effectiveness-but their structure was similar and they showed characteristics typical of indeterminate nodules, such as persistent meristematic tissue and a gradient of cells at different stages of development. Many starch grains were present in inner cortex cells and interstitial cells of infected tissue. Infected cells were densely packed with bacteroids, which contained many poly-beta-hydroxybutyrate granules. The high incidence of these granules, together with high levels of starch accumulation in interstitial cells, suggested low N-2-fixation efficiency of the rhizobia isolates used for inoculation. In the symbiosomes of early-senescent infected cells, reticulum-like structures, small vesicles and a fibrillar material were observed; these may be related to bacteroid degradation. In the cytoplasm of late-senescent infected cells, many vesicles and membrane-like structures were observed, probably associated with membrane degradation of bacteroids and peribacteroids. The total biomass of plants inoculated with rhizobia was low and their xylopodia and shoots had low levels of N compared with non-inoculated plants fertilized with ammonium nitrate. However, inoculated plants did not show N-deficiency symptoms and grew better than non-inoculated plants without N fertilization. These growth results, together with ultrastructural observations of nodules, suggest that nitrogen fixation of rhizobia isolates associated with Anadenanthera peregrina var. falcata roots is poor. (C) 2002 Annals of Botany Company.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Insects manifest effective immune responses that include both cellular and humoral components. Morphological and quantitative aspects of cellular and Immoral cooperation during nodule formation in Chrysomya megacephala hemolymph against Saccharomyces cerevisae yeast cells were demonstrated for the first time. The analyses were performed in non-injected larvae (NIL), saline-injected larvae (SIL) and yeast-injected larvae (YIL). The hemolymph of injected groups was collected 0.5, 1, 2, 4, 12, 24, 36, or 48-h post-injection. Morphological aspects of YIL nodulation were investigated using transmission electron microscopy (TEM). Quantitative analyses consisted of total (THC) and differential hemocyte counts (DHC) in all the groups and total yeast count (TYC) in YIL, which were performed in an improved Neubauer chamber. Nodule formation was initiated at approximately 2-h post-injection. Twelve hours after the injection, TEM revealed the presence of an amorphous membrane, at the same time that circulating hemocyte number decreased significantly contrasting the increase of yeast number. Our results showed the ability of C megacephala hemolymph to perform humoral encapsulation when hemocyte population is insufficient to eliminate the microorganisms, warranting consideration in future investigations on the relative roles played by cellular and humoral elements of innate immunity of this calliphorid. (c) 2007 Elsevier B.V. All rights reserved.

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Endometrial stromal sarcoma is a rare neoplasm of the uterus. Extrauterine locations of this neoplasm, excluding metastases or local extension, are even more unusual and are usually associated with the presence of endometriosis. The authors report a case of endometrial stromal sarcoma presenting as a vaginal wall nodule, without any sign of primary uterine tumor after extensive evaluation or presence of endometriosis. The morphology, immunohistochemical profile, differential diagnoses, and pathogenesis are discussed, as well as a review of the literature on this issue. © 2004 Elsevier Inc. All rights reserved.

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The Sister Mary Joseph (SMJ) nodule is a clinical sign of metastatic cancer involving the umbilicus. The vast majority of these instances represent adenocarcinomas arising from ovarian or colorectal primaries. We present a patient who presented with ascites and the SMJ lesion that turned out to be a metastatic gastrointestinal stromal tumor after fine needle aspiration biopsy was performed. The lesion was subsequently histologically confirmed. Gastrointestinal stroma tumor involving the umbilicus is exceedingly uncommon and only rarely presents in this fashion. The cytomorphological features, differential diagnosis, and comparison with the tissue specimen are made. © 2006 Elsevier Inc. All rights reserved.

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This letter describes a novel algorithm that is based on autoregressive decomposition and pole tracking used to recognize two patterns of speech data: normal voice and disphonic voice caused by nodules. The presented method relates the poles and the peaks of the signal spectrum which represent the periodic components of the voice. The results show that the perturbation contained in the signal is clearly depicted by pole's positions. Their variability is related to jitter and shimmer. The pole dispersion for pathological voices is about 20% higher than for normal voices, therefore, the proposed approach is a more trustworthy measure than the classical ones. © 2007.

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It is well established that nitrate is a potent inhibitor of nodulation and nitrogen fixation in legumes. The objective of this study was to demonstrate the relative insensitivity of these processes to nitrate with Calopogonium mucunoides, a tropical South American perennial legume, native to the cerrado (savannah) region. It was found that nodule number was reduced by about half in the presence of high levels of nitrate (15 mM) but nodule growth (total nodule mass per plant) and nitrogen fixation (acetylene reduction activity and xylem sap ureide levels) were not affected. Other sources of N (ammonium and urea) were also without effect at these concentrations. At even higher concentrations (30 mM), nitrate did promote significant inhibition (ca. 50%) of acetylene reduction activity, but no significant reduction in xylem sap ureides was found. The extraordinary insensitivity of nodulation and N2 fixation of C. mucunoides to nitrate suggests that this species should be useful in studies aimed at elucidating the mechanisms of nitrate inhibition of these processes. © 2010 Springer Science+Business Media B.V.

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Introduction. Necrotizing sialometaplasia is a benign, self-limiting and rare inflammatory disease which, on clinical and histological examination, mimics malignant neoplasms. Case report. We report the case of a healthy 25-year-old Caucasian woman with a three-week history of a painless lump on her hard palate. Oral examination revealed a nodule consisting of two lobules on the right side that measured 2.5 cm. Her mucosa was normal in color and a fluctuant area was detected in the posterior region upon palpation. Our patient was submitted to incisional biopsy and histopathological examination. The histological diagnosis was necrotizing sialometaplasia. The lesion had healed spontaneously after 30 days, with observed signs of involution of the nodule. Conclusion: Histopathological examination is necessary for the diagnosis of necrotizing sialometaplasia because the clinical features of this condition can mimic other diseases, particularly malignant neoplasms. © 2011 Oliveira Alves et al; licensee BioMed Central Ltd.

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Introduction. Granular cell tumor is an uncommon neoplasm that can occur in any part of the body, including the orofacial region. The tumor is usually benign, but there are reports of cases in which the tumor shows a locally aggressive behavior, malignancy, and distant metastases. The most widely accepted hypothesis is that granular cell tumor arises from the altered metabolism of Schwann cells. The tumor is typically asymptomatic and appears as a nodule that does not exceed 3 cm. Case presentation. In case 1, a 26-year-old Caucasian man was seen at the Oral Medicine out-patient clinic of the São José dos Campos Dental School, Universidade Estadual Paulista, with a 'small blister on the tongue', which he had noted approximately three years ago. The nodule was located on the dorsum of the tongue, measured about 1.5 cm in diameter, and was not tender to palpation. Treatment consisted of an excisional biopsy performed on the basis of the diagnostic hypothesis of granular cell tumor, which was confirmed by microscopic analysis. In case 2, a 31-year-old Caucasian woman attended the out-patient clinic of the São José dos Campos Dental School, Universidade Estadual Paulista, with a five-year history of a 'painful lump on the tongue'. Intra-oral examination revealed the presence of a nodular lesion measuring approximately 0.8 cm in diameter, which was located deep in the submucosa of the right lateral margin of the tongue. Treatment consisted of an excisional biopsy performed on the basis of the differential diagnosis of neurofibroma and granular cell tumor. Microscopic analysis defined the final diagnosis of granular cell tumor. Conclusions: Granular cell tumor is an uncommon tumor that must be carefully diagnosed and treated correctly. © 2012 Sena Costa et al; licensee BioMed Central Ltd.

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We explored the interaction between radiation of different wavelength and jasmonic acid (JA) or brassinosteroids (BR) on leaf senescence-induced oxidative stress. Three approaches were used: 1) jasmonic acid insensitive1-1 (jai1-1) and brassinosteroid-deficient [dumpy (dpy)] mutants were treated with red (R) or far-red (FR) radiation; 2) phytochromedeficient aurea (au) and high pigment-1 (hp-1) (radiation exaggerated response) mutants were treated with methyl jasmonate (MeJA) or epibrassinolide (epiBL); and 3) double mutants au jai1-1 and au dpy were produced. Leaf chlorophyll content, lipid peroxidation, and antioxidant enzyme activities were determined. After senescence induction in detached leaves, we verified that the patterns of chlorophyll degradation of hormonal and photomorphogenic mutants were not significantly different in comparison with original cv. Micro-Tom (MT). Moreover, there was no significant change in lipid peroxidation measured as malondialdehyde (MDA) production, as well as catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities in the hormonal mutants. Exogenous BR increased CAT and APX activities in MT, au, and hp-1. As concerns the double mutants, severe reduction in H2O2 production which was not accompanied by changes in MDA content, and CAT and APX activities was observed during senescence in au dpy. The results suggest that JA and BR do not participate in light signaling pathway during leaf senescence-induced oxidative stress. © 2013 Springer Science+Business Media Dordrecht.

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Background: The problem of diagnosing whether a solitary pulmonary nodule is benign or malignant is even greater in developing countries due to a higher prevalence of infectious diseases. These infections generate a large number of patients who are generally asymptomatic and with a pulmonary nodule that cannot be accurately defined as having benign or malignant etiology.Purpose: To verify the percentages of benign versus malignant non-calcified nodules, the length of time after contrast agent injection is spiral computed tomography (CT) most sensitive and specific, and whether three postcontrast phases are necessary.Material and Methods: We studied 23 patients with solitary pulmonary nodules identified on chest radiographs or CT. Spiral scans were obtained with Swensen protocol, but at 3, 4, and 5 min after contrast injection onset. Nodules were classified as benign or malignant by histopathological examination or by an absence or presence of growth after 2 years of follow-up CT.Results: Of the 23 patients studied, 18 (78.2%) showed a final diagnosis of benign and five (21.7%) malignant nodules. Despite the small sample size, we obtained results similar to those of Swensen et al., with 80.0% sensitivity, 55.5% specificity, and 60.8% accuracy. Four minutes gave the greatest mean enhancement in both malignant and benign lesions.Conclusion: Small non-calcified benign nodules were much more frequent than malignant nodules. The best time for dynamic contrast-enhanced CT density analysis was 4 min postcontrast. As well as saving time and money, this simplified Swensen protocol with only precontrast and 4 min postcontrast phases also reduces patient exposure to ionizing radiation.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Alterations in the hypothalamic-pituitary-gonadal axis in females determine the transition from regular to irregular reproductive cycles, with loss of fertility. Stimulation of noradrenergic neurons of the anteroventral periventricular neurons (AVPV) is essential for regular reproductive cycles. Therefore, we examined the activity of neurons of the AVPV and measure the noradrenaline (NE) of acyclic rats, in constant estrus, and compared it with that of cyclic rats in estrus. Female cyclic (4-5months) and acyclic (17-18months) rats were euthanized at 10, 14, and 18h in estrus. Brains were processed for immunoreactivity to antigens related to Fos (FRA) in AVPV, and the NE was determined by HPLC-ED. Plasma concentrations of LH, FSH, E2 and P4 were determined. In the acyclic animals, plasma LH was higher but the FSH was lower. There was decreasing P4 at different times, while the E2 was constant and lower in acyclic rats. FRA-ir expression in AVPV neurons of acyclic rats as well as turnover of NE was higher when compared with cyclic group. The preliminary findings showed increased activity in AVPV neurons in aging contribute to changes in the temporal pattern of neuroendocrine signaling, compromising the accuracy of inhibitory and stimulatory effects, causing irregularity in the estrous cycle and determining reproductive senescence.

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O objetivo deste trabalho foi identificar e quantificar os açúcares em frutos de pessegueiro da variedade 'Biuti', armazenados sob condições de ambiente (27,3ºC; 70% UR) e sob refrigeração (4ºC; 90%), comparar as diferenças entre os teores de açúcares nas duas condições de armazenamento. A identificação e a quantificação precisa dos açúcares (glicose, frutose e sacarose) foi realizada por cromatografia em fase líquida HPLC. Verificou-se que a sacarose foi o açúcar encontrado em maior quantidade, sendo verificado apenas traços de glicose e frutose em alguns frutos. Sob condições ambientais, os teores de sacarose do 3º até o 9º dia de armazenamento não diferiram significativamente entre si; entretanto, no 12º dia, os frutos obtiveram baixos teores de sacarose, pois os mesmos já estavam em processo de senescência. Sob refrigeração, o aumento nos teores de açúcares dos frutos ocorreu gradativamente durante todo o armazenamento, e ao final do mesmo, verificaram-se os maiores teores de sacarose, frutose e glicose, os quais eram mais elevados do que os encontrados nos frutos armazenados sob condições ambientais.