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31.
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. 相似文献
32.
Neves SR Machado CR Pinto AM Borges AH Cunha FQ Camargos ER 《Histology and histopathology》2006,21(8):803-812
The rat model of hypertension induced by prolonged treatment with Nomega-nitro-L-arginine methyl ester (L-NAME) has been extensively used. However, the effects on cardiac autonomic innervation are unknown. Here, the cardiac sympathetic innervation is analyzed in parallel with myocardial lesions and leukocyte infiltration during L-NAME (40 mg/Kg body weight/day, orally) treatment. The occurrence of cardiomyocyte hypertrophy, a controversial matter, is also addressed. Degenerating cardiomyocytes and focal inflammation occurred one day after treatment. Inflammatory lesions became gradually more frequent until day 7. At day 14 fibroblast-like cells were outstanding. Interstitial and perivascular connective tissue increased from day 28 on. In the left ventricle, cardiomyocyte hypertrophy occurred only around the damaged area during the first 14 days. After 28 days, it became more widespread. In the right ventricle, the hypertrophic cardiomyocytes were restricted to damaged areas. Significant reduction of the noradrenergic nerve terminals occurred from day 3 to 28. The area occupied by ED1+ (hematogenous) macrophages increased until day 7, and dropped to control levels by day 10. ED2+ (resident) macrophages increased from day 3 to 7 and remained higher than control values up to day 77. Animals receiving both L- NAME and aminoguanidine (AG), an inducible nitric oxide synthase (iNOS) inhibitor (65 mg/Kg body weight/day, orally), showed significant decrease in the nitrite serum levels, sympathetic denervation and macrophage infiltration at day 7. No denervation was detectable at day 14 of double treatment, using subcutaneous AG. Our findings favor a role for ED1+ macrophages and iNOS in the hypertension-induced denervation process. 相似文献
33.
Moura SB Almeida LR Guerra JB Rocha GA Camargos Rocha AM Melo FF Corrêa-Oliveira R Bittencourt P Carvalho SD Magalhães Queiroz DM 《Microbes and infection / Institut Pasteur》2008,10(14-15):1477-1483
Helicobacter pylori infection is mainly acquired in childhood, and polymorphisms in the host genes coding for Toll-like receptors (TLRs) may influence the innate and adaptive immune response to the infection, affecting the susceptibility to H. pylori or the disease outcomes. Our aim was to investigate whether TLR4, TLR2, and TLR5 polymorphisms were associated with H. pylori susceptibility and risk for duodenal ulcer in children. Gastric biopsy specimens were obtained at endoscopy for evaluation of H. pylori status, TLR4, TLR2 and TLR5 polymorphisms from 486 children (254 H. pylori-negative and 232 H. pylori-positive: 72 with and 160 without duodenal ulcer). cagA status of H. pylori infection was investigated by PCR. The levels of gastric cytokines were detected by ELISA. H. pylori-positivity or duodenal ulcer were not associated with TLR2, TLR4 or TLR5 polymorphisms. Otherwise, the presence of TLR4 polymorphic allele was associated with infection by cagA-positive strains and with increased gastric levels of interleukin-8 and interleukin-10. TLR4 polymorphism might ultimately contribute to more severe consequences of the infection in adulthood since it was associated with susceptibility to cagA-positive H. pylori infection early in life. 相似文献
34.
Oliveira Flavia R. Casalechi Maíra Carneiro Márcia M. de Ávila Ivete Dela Cruz Cynthia Del Puerto Helen L. Camargos Aroldo F. Abrão Maurício S. Reis Fernando M. 《Molecular biology reports》2021,48(10):6863-6870
Molecular Biology Reports - Human endometrium harbors stem/progenitor cells (SPCs) that may contribute to the establishment of endometriosis when seeded outside the uterus. Oct-4, C-kit and... 相似文献
35.
Soil nitrogen recovery and seasonal changes of xylem sap amino acids of Amazonian tree species following pasture abandonment 总被引:1,自引:0,他引:1
de Araújo Vanderlei Borboni Ferreira Justino Gilberto Costa da Silva Carlos Eduardo Moura Vera Saul Alfredo Antezzana Lins Lays Sodek Ladaslav de Camargos Liliane Santos Pereira Luis Octávio Vieira de Carvalho Gonçalves José Francisco 《Plant Ecology》2019,220(6):633-648
Plant Ecology - We conducted this study to understand the dynamics of revegetation by examining the levels of mineral nitrogen (NO3? and NH4+) in soil and the capacity of nitrogen use by the... 相似文献
36.
Souza ET Maia PJ Azevedo EM Kaiser CR Resende JA Pinheiro CB Heinrich TA da Silva RS Scarpellini M 《Journal of inorganic biochemistry》2011,105(12):1767-1773
Continuing our interest in tridentate ligands to develop new prototypes of cobalt-based metallodrugs for combating cancer, modifications in the backbone of HL1, [(2-hydroxybenzyl)(2-(pyridil-2-yl)ethyl]amine) were proposed in order to modulate the redox potential of new Co(III) complexes. Three ligands with electron withdrawing groups were synthesized: HL2: [(2-hydroxy-5-nitrobenzyl)(2-(pyridil-2-yl)ethyl]amine); HL3: [(2-hydroxybenzyl)(2-(pyridil-2-yl)ethyl]imine) and HL4: [(2-hydroxy-5-nitrobenzyl)(2-(pyridil-2-yl)ethyl]imine). They were used to obtain the respective mononuclear complexes 2, 3 and 4, which are discussed compared to the previous reported complex 1 (obtained from HL1). The new complexes were characterized and studied by several techniques including X-ray crystallography, elemental and conductimetric analysis, IR, UV-vis and 1H NMR spectroscopies, and electrochemistry. The substitutions of the group in the para position of the phenol (HL1 and HL2) and the imine instead of the amine (HL3 and HL4), promote anodic shifts in the complexes reduction potentials. The influence of these substitutions in the biological activities of the Co(III) complexes against the murine melanoma cell line (B16F10) was also evaluated. Little effect was observed on cellular viability decrease for all free ligands, however the coordination to Co(III) enhances their activities in the following range: 1 > 4 ≈ 2 > 3. The data suggest that no straight correlation can be addressed between the reduction potential of the Co(III) center and the cell viability. 相似文献
37.
Freire de Melo F Rocha AM Rocha GA Pedroso SH de Assis Batista S Fonseca de Castro LP Carvalho SD Bittencourt PF de Oliveira CA Corrêa-Oliveira R Magalhães Queiroz DM 《Microbes and infection / Institut Pasteur》2012,14(4):341-347
Th17 cells seem to have an important role in the efficacy of vaccines against Helicobacter pylori. Because children are a target group for human vaccination and Th17/T(reg) cells have intrinsically linked and antagonic commitments, we compared the gastric levels of Th17- and T(reg)-associated cytokines of children and adults. IL-6, IL-10 and TGF-β1 levels and Foxp3(+) cell numbers were higher, but IL-1β, IL-17A and IL-23 were lower in infected children than in infected adults. In conclusion T(reg) instead of Th17 cell response to H. pylori-infection predominates in children. 相似文献
38.
Pereira Fde A Tavares RL Camargos AF da Silva Filho AL 《Cell biology international》2012,36(8):755-757
Telomerase is associated with cell proliferation capacity, protection and stabilization of chromosomes. TA (telomerase activity) can be detected in highly replicative cells, e.g. stem and cancer cells. Most available mESC (mouse embryonic stem cell) research is done with a few cell lines. The purpose of this study has been to evaluate the TA in different passages of newly isolated mESC. TRAP (Telomeric Repeat Amplification Protocol)-ELISA method was used in a semi-quantitative evaluation of TA. Three mESC lineages were investigated (CT2, CT3 and CT4) at three different passages (P13, P15 and P19). In contrast with previous studies, these mESC lines did not show the same TA throughout their passages, having initially low TA values, followed by a subsequent rise and stabilization. 相似文献
39.
Gomes RT Camargos RP Viotti AP Tavares AP Revelo MP Freitas TV 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2002,131(3):295-301
The local absorption rate, clearance and tissue distribution of Crotalus durissus terrificus venom, (Cdt) were examined using a two-antibody sandwich ELISA assay. We compared the biodistribution of both free or encapsulated Cdt in mice. Following subcutaneous injection of 10 microg/mouse of free Cdt (0.8 LD50), venom was detected in serum after 15 min, showed its highest level at 30 min (45+/-5 ng/ml) and was cleared from the circulation after 6 h. After 2 h of inoculation, venom was detected in the kidney (57+/-9 ng/g of tissue), spleen (18+/-4 ng/g of tissue) and brain (14+/-6 ng/g of tissue). For both subcutaneous or intravenous injection of free Cdt, venom was firstly detected in the kidney. No Cdt appeared either in the kidney, spleen, brain, or other tissues after subcutaneous inoculation of encapsulated venom even though a higher dose was used, 25 microg/mouse (2 LD50). Venom remained at the site of injection for a period of 1 week. Following intravenous injection of encapsulated venom (5 microg/mouse, 2 LD50), venom was detected in liver and spleen tissues. The biodistribution of encapsulated venom is discussed in relation to the effects of reduction of toxicity and increase of adjuvanticity. 相似文献
40.
Camargos Simone M. Valente Soares Lucia M. Sawazaki Eduardo Bolonhezi Denizart Castro Jairo L. Bortolleto Nelson 《Mycopathologia》2003,155(4):219-228
Fifty-six Brazilian commercial maize cultivars were examined for FB1 and FB2 accumulation after two non-consecutive growing seasons. During the 94/95 growing season 35 cultivars were planted at three locations in the state of São Paulo, Brazil. All samples (total of 105) were contaminated (0.10 g/g–6.58 g/g FB1 and 0.04 g/g–2.15 g/g FB2). During the 97/98 growing season, 8 of the cultivars used during 94/95 and 21 others were replanted at the same locations. All 87 samples were contaminated (1.15 g/g–43.80 g/g FB1 and 0.08 g/g–11.65 g/g FB2). One cultivar accumulated significantly less fumonisins in all locations during both growing seasons, indicating that some degree of selection may be possible even in climates that favor F. moniliforme (verticillioides) infection of maize. The presence of water surplus in soil from kernel maturity to harvest correlated with concentrations of FB1 in the grain for the 8 cultivars planted during both seasons at three locations. Observed trends indicated that water excesses and deficits from silking to harvest increased fumonisin levels. The difference in the incidence of FB1, FB2, and FB1 + FB2 was significant between growing seasons, planting locations and between cultivars. Neither the level of hybridization, nor the type of endosperm, nor the length of the vegetative cycle showed any effect on the FB1 contamination.This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献