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31.
In this work we assessed spatial and temporal variation of leaf pigment content of Clusia hilariana, a dominant CAM tree on the sandy coastal plains of SE Brazil. Chlorophyll a + b concentration, chlorophyll a/b ratio, and total carotenoid concentration were measured three times during the wet season. Chlorophyll a + b and total carotenoids decreased while the chlorophyll a/b ratio increased after a series of dry spells. We discuss our results in the context of Clusia literature, and argue that leaf-level pigmentation changes are an important source of phenotypic flexibility during acclimation
to fluctuating light levels and groundwater availability. 相似文献
32.
Damasceno DC Volpato GT de Mattos Paranhos Calderon I Cunha Rudge MV 《Animal reproduction science》2002,72(3-4):235-244
A considerable amount of clinical and experimental evidence now exists suggesting the involvement of free radical-mediated oxidative processes in the pathogenesis of diabetic complications. If the diabetic state is associated with a generalized increase in oxidative stress, it might well be reflected in the alterations in embryonic and fetal development during pregnancy. In the present study, incidence of the malformed fetuses, biochemical parameters and antioxidant system activity of streptozotocin (STZ)-induced diabetic pregnant rats was investigated and the results obtained were compared with those of the control group (non-diabetic). Virgin female Wistar rats were injected with 40 mg/kg streptozotocin (STZ) before mating. All the females were killed on Day 21 of pregnancy and the fetuses were analyzed. A maternal blood sample was collected by venous puncture and the maternal liver was removed for biochemical measurement. The diabetic dams presented hyperglycemia, hyperlipemia, hypertriglyceridemia, hypercholesterolemia, hyperuricemia, decreased reduced glutathione (GSH), hepatic glycogen and superoxide dismutase (SOD) determinations. There was an increased incidence of skeletal and visceral malformation in fetuses from diabetic rats. Our findings suggest that oxidative stress occurs in the diabetic pregnant state, which might promote maternal homeostasis alterations. These diabetic complications might be a contributory factor to conceptus damage causing embryonic death (abortion/miscarriage) or the appearance of malformations in the fetuses of diabetic dams. Antioxidant treatment of women with diabetes may be important in future attempts to prevent congenital malformations. 相似文献
33.
Cdc25B phosphatase, an important regulator of the cell cycle, forms an intramolecular disulfide bond in response to oxidation leading to reversible inactivation of phosphatase activity. We have obtained a crystallographic time course revealing the structural rearrangements that occur in the P-loop as the enzyme goes from its apo state, through the sulfenic (Cys-SO(-)) intermediate, to the stable disulfide. We have also obtained the structures of the irreversibly oxidized sulfinic (Cys-SO(2)(-)) and sulfonic (Cys-SO(3)(-)) Cdc25B. The active site P-loop is found in three conformations. In the apoenzyme, the P-loop is in the active conformation. In the sulfenic intermediate, the P-loop partially obstructs the active site cysteine, poised to undergo the conformational changes that accompany disulfide bond formation. In the disulfide form, the P-loop is closed over the active site cysteine, resulting in an enzyme that is unable to bind substrate. The structural changes that occur in the sulfenic intermediate of Cdc25B are distinctly different from those seen in protein tyrosine phosphatase 1B where a five-membered sulfenyl amide ring is generated as the stable end product. This work elucidates the mechanism by which chemistry and structure are coupled in the regulation of Cdc25B by reactive oxygen species. 相似文献
34.
Bittar RC Nogueira RS Vieira-Gonçalves R Pinho-Ribeiro V Mattos MS Oliveira-Neto MP Coutinho SG Da-Cruz AM 《Memórias do Instituto Oswaldo Cruz》2007,102(5):625-630
Subclinical or asymptomatic infection is documented in individuals living in endemic areas for leishmaniasis suggesting that the development of an appropriate immune response can control parasite replication and maintain tissue integrity. A low morbidity indicates that intrinsic factors could favor resistance to Leishmania infection. Herein, leishmanial T-cell responses induced in subjects with low susceptibility to leishmaniasis as asymptomatic subjects were compared to those observed in cured cutaneous leishmaniasis (CCL) patients, who controlled the disease after antimonial therapy. All of them have shown maintenance of specific long-term immune responses characterized by expansion of higher proportions of CD4+ as compared to CD8+ Leishmania reactive T-lymphocytes. Asymptomatic subjects had lower indexes of in vitro Leishmania induced lymphoproliferative responses and interferon-gamma (IFN-gamma) production in comparison to CCL patients. On the other hand, interleukin (IL-10) production was much higher in asymptomatics than in CCL, while no differences in IL-5 levels were found. In conclusion, long lived T-cell responses achieved by asymptomatic individuals differed from those who had developed symptomatic leishmaniasis in terms of intensity of lymphocyte activation (proliferation or IFN-gamma) and regulatory mechanisms (IL-10). The absence of the disease in asymptomatics could be explained by their intrinsic ability to create a balance between immunoregulatory (IL-10) and effector cytokines (IFN-gamma), leading to parasite destruction without producing skin tissue damage. The establishment of profiles of cell-mediated immune responses associated with resistance against Leishmania infection is likely to make new inroads into understanding the long-lived immune protection against the disease. 相似文献
35.
Katherine A. Mattos Viviane C. G. Oliveira Marcia Berrêdo‐Pinho Julio J. Amaral Luis Caetano M. Antunes Rossana C. N. Melo Chyntia C. D. Acosta Danielle F. Moura Roberta Olmo Jun Han Patricia S. Rosa Patrícia E. Almeida B. Brett Finlay Christoph H. Borchers Euzenir N. Sarno Patricia T. Bozza Georgia C. Atella Maria Cristina V. Pessolani 《Cellular microbiology》2014,16(6):797-815
36.
37.
Lack of association of the G22A polymorphism of the ADA gene in patients with ankylosing spondylitis
Camargo U Toledo RA Cintra JR Nunes DP Acayaba de Toledo R Brandão de Mattos CC Mattos LC 《Genetics and molecular research : GMR》2012,11(2):1178-1184
Genes located outside the HLA region (6p21) have been considered as candidates for susceptibility to ankylosing spondylitis. We tested the hypothesis that the G22A polymorphism of the adenosine deaminase gene (ADA; 20q13.11) is associated with ankylosing spondylitis in 166 Brazilian subjects genotyped for the HLA*27 gene (47 patients and 119 controls matched for gender, age and geographic origin). The HLA-B*27 gene and the G22A ADA polymorphism were identified by PCR with sequence-specific oligonucleotide probes and PCR-RFLP, respectively. There were no significant differences in frequencies of ADA genotypes [odds ratio (OR) = 1.200, 95% confidence interval (CI) = 0.3102-4.643, P > 0.8] and ADA*01 and ADA*02 alleles (OR = 1.192, 95%CI = 0.3155-4.505, P > 0.8) in patients versus controls. We conclude that the G22A polymorphism is not associated with ankylosing spondylitis. 相似文献
38.
D C Damasceno G T Volpato I de Mattos Paranhos Calderon R Aguilar M V Cunha Rudge 《Phytomedicine》2004,11(2-3):196-201
Bauhinia forficata, commonly known as "paw-of-cow", is widely used in Brazil folk medicine for the treatment of Diabetes mellitus. The purposes of present study were to determine the repercussions of diabetes on the defense system against oxidative stress in pregnant female rats and to characterize the influence of the treatment with Bauhinia forficata extract on the antioxidant system, glycemic control, hepatic glycogen, cholesterol, triglycerides, total proteins and lipids. Virgin female Wistar rats were injected with 40 mg/kg streptozotocin (STZ) before mating. Oral administration of an aqueous extract of Bauhinia forficata leaves was given to non-diabetic and diabetic pregnant rats in 3 doses: 500 mg/kg from 0 to 4th day of pregnancy, 600 mg/kg from 5th to 14th day and 1000 mg/kg from 15th to 20th day. All the females were killed on the day 21 of pregnancy. A maternal blood sample was collected by venous puncture and the maternal liver was removed for biochemical measurement. The diabetic pregnant rats presented hyperglycemia, hyperlipemia, hypertriglyceridemia, hypercholesterolemia, hyperuricemia, decreased determinations of reduced glutathione (GSH) and superoxide dismutase (SOD). Treatment with B. forficata extract did not interfere in the albumin, total protein and lipid, triglyceride, cholesterol and SOD determinations. Increased hepatic glycogen, decreased uric acid concentration and increased GSH activity was observed. This last fact suggests that the plant may have some action on antioxidant defense system. However, the demonstration of the active component present in B. forficata responsible for its antioxidant effect and the increase in hepatic glycogen deserve further investigation. 相似文献
39.
Consuelo Latorre Fortes-Dias Roberta Márcia Marques dos Santos Angelo José Magro Marcos Roberto de Mattos Fontes Carlos Chávez-Olórtegui Claude Granier 《Biochimie》2009,91(11-12):1482-1492
Crotoxin (CA.CB) is a β-neurotoxin from Crotalus durissus terrificus snake venom that is responsible for main envenomation effects upon biting by this snake. It is a heterodimer of an acidic protein (CA) devoid of any biological activity per se and a basic, enzymatically active, PLA2 counterpart (CB). Both lethal and enzymatic activities of crotoxin have been shown to be inhibited by CNF, a protein from the blood of C. d. terrificus snakes. CNF replaces CA in the CA.CB complex, forming a stable, non-toxic complex CNF.CB. The molecular sites involved in the tight interfacial protein–protein interactions in these PLA2-based complexes have not been clearly determined. To help address this question, we used the peptide arrays approach to map possible interfacial interaction sites in CA.CB and CNF.CB. Amino acid stretches putatively involved in these interactions were firstly identified in the primary structure of CB. Further analysis of the interfacial availability of these stretches in the presumed biologically active structure of CB, suggested two interaction main sites, located at the amino-terminus and β-wing regions. Peptide segments at the carboxyl-terminus of CB were also suggested to play a secondary role in the binding of both CA and CNF. 相似文献