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281.
Summary. Although peroxynitrite is believed to be one of the most efficient tyrosine-nitrating species of biological relevance so far identified, its nitration efficiency is nevertheless limited. In fact, the nitrating species formed through peroxynitrite decay are caged radicals (OH/NO2 or, in the presence of carbon dioxide, CO3
–/NO2) and the fraction that escapes from the solvent cage does not exceed 30–35%. One exception may be represented by metal-containing compounds that can enhance the formation of nitrotyrosine through a bimolecular reaction with peroxynitrite. Moreover, if the metal is also regenerated in the reaction, the compound is considered a nitration catalysts and the yield of tyrosine nitration enhanced several fold. Examples of peroxynitrite-dependent nitration catalysts are the Mn-superoxide dismutase, some cytochromes and several metalloporphyrins. On the contrary, it has been claimed that some hemoproteins are scavengers of peroxynitrite and play a role in limiting its biodamaging and bioregulatory activity. In this review, we discuss the case of hemoglobin, which is probably the major target of peroxynitrite in blood. This protein has been reported to protect intracellular and extracellular targets from peroxynitrite-mediated tyrosine nitration. This property is shared with myoglobin and cytochrome c. The possible mechanisms conferring to these proteins a peroxynitrite scavenging role are discussed.Present address: Laboratorio di Tossicologia Applicata ed Ecotossicologia, Istituto Superiore di Sanità, Rome, Italy. 相似文献
282.
Dornelles CL Bonatto SL De Freitas LB Salzano FM 《American journal of physical anthropology》2005,127(4):439-448
A total of 1,159 mitochondrial DNA samples from two Mongolian, two Siberian, and 25 South Native American populations was surveyed for the presence of the C16278T mutation, frequently found in haplogroup X. Material from 25 carriers of that mutation was then sequenced for the hypervariable segment I (HVS-I) control region, and those that still were not classifiable in classical Amerindian haplogroups were further studied. The tests involved all the control region, as well as the presence of characteristic mutations in seven coding fragments, totalling 5,760 base pairs. The results indicate that haplogroup X is not present in these samples. 相似文献
283.
Lima-Rosa CA Canal CW Streck AF Freitas LB Delgado-Cañedo A Bonatto SL Salzano FM 《Animal genetics》2004,35(4):278-284
A total of 100 chickens from the Brazilian (blue-egg Caipira) native breed were studied in relation to exon 2 of the B-F genes of the major histocompatibility complex (MHC) region. After a first screening on 100 birds, 22 animals were selected for amplification, cloning and sequencing experiments of exons 2-4 (a total of 1048 bp) of their DNA. Twenty-three sequences were obtained, of which at least 10 appear novel. Inferred protein sequences were compared with those previously described, totalling 41 different sequences with amino acid changes in 33 of the 88 sites in alpha1, and 34 of the 91 sites in alpha2 domains. Allele expression was investigated in these animals through cloning experiments. The blue-egg Caipira chickens may provide a source of novel B-F alleles for genetic improvement programmes. 相似文献
284.
Rafael Bisso‐Machado Claudio Bravi Michael D. Coble Francisco M. Salzano Tábita Hünemeier Maria Cátira Bortolini 《American journal of physical anthropology》2013,150(3):453-463
Native Americans are characterized by specific and unique patterns of genetic and cultural/linguistic diversities, and this information has been used to understand patterns of geographic dispersion, and the relationship between these peoples. Particularly interesting are the Tupi and Je speaker dispersions. At present, a large number of individuals speak languages of these two stocks; for instance, Tupi‐Guarani is one of the official languages in Paraguay, Bolivia, and the Mercosul economic block. Although the Tupi expansion can be compared in importance to the Bantu migration in Africa, little is known about this event relative to others. Equal and even deeper gaps exist concerning the Je‐speakers' expansion. This study aims to elucidate some aspects of these successful expansions. To meet this purpose, we analyzed Native American mtDNA complete control region from nine different populations and included HVS‐I sequences available in the literature, resulting in a total of 1,176 samples investigated. Evolutionary relationships were explored through median‐joining networks and genetic/geographic/linguistic correlations with Mantel tests and spatial autocorrelation analyses. Both Tupi and Je showed general traces of ancient or more recent fission – fusion processes, but a very different pattern of demographic expansion. Tupi populations displayed a classical isolation‐by‐distance pattern, while Je groups presented an intricate and nonlinear mode of dispersion. We suggest that the collective memory and other cultural processes could be important factors influencing the fission – fusion events, which likely contributed to the genetic structure, evolution, and dispersion of Native American populations. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
285.
Yoony YJ Gent Karin Weijers Carla FM Molthoff Albert D Windhorst Marc C Huisman Desirée EC Smith Sumith A Kularatne Gerrit Jansen Philip S Low Adriaan A Lammertsma Conny J van der Laken 《Arthritis research & therapy》2013,15(2):R37
Introduction
Detection of (subclinical) synovitis is relevant for both early diagnosis and monitoring of therapy of rheumatoid arthritis (RA). Previously, the potential of imaging (sub)clinical arthritis was demonstrated by targeting the translocator protein in activated macrophages using (R)-[11C]PK11195 and positron emission tomography (PET). Images, however, also showed significant peri-articular background activity. The folate receptor (FR)-β is a potential alternative target for imaging activated macrophages. Therefore, the PET tracer [18F]fluoro-PEG-folate was synthesized and evaluated in both in vitro and ex vivo studies using a methylated BSA induced arthritis model.Methods
[18F]fluoro-PEG-folate was synthesized in a two-step procedure. Relative binding affinities of non-radioactive fluoro-PEG-folate, folic acid and naturally circulating 5-methyltetrahydrofolate (5-Me-THF) to FR were determined using KB cells with high expression of FR. Both in vivo [18F]fluoro-PEG-folate PET and ex vivo tissue distribution studies were performed in arthritic and normal rats and results were compared with those of the established macrophage tracer (R)-[11C]PK11195.Results
[18F]fluoro-PEG-folate was synthesized with a purity >97%, a yield of 300 to 1,700 MBq and a specific activity between 40 and 70 GBq/µmol. Relative in vitro binding affinity for FR of F-PEG-folate was 1.8-fold lower than that of folic acid, but 3-fold higher than that of 5-Me-THF. In the rat model, [18F]fluoro-PEG-folate uptake in arthritic knees was increased compared with both contralateral knees and knees of normal rats. Uptake in arthritic knees could be blocked by an excess of glucosamine-folate, consistent with [18F]fluoro-PEG-folate being specifically bound to FR. Arthritic knee-to-bone and arthritic knee-to-blood ratios of [18F]fluoro-PEG-folate were increased compared with those of (R)-[11C]PK11195. Reduction of 5-Me-THF levels in rat plasma to those mimicking human levels increased absolute [18F]fluoro-PEG-folate uptake in arthritic joints, but without improving target-to-background ratios.Conclusions
The novel PET tracer [18F]fluoro-PEG-folate, designed to target FR on activated macrophages provided improved contrast in a rat model of arthritis compared with the accepted macrophage tracer (R)-[11C]PK11195. These results warrant further exploration of [18F]fluoro-PEG-folate as a putative PET tracer for imaging (sub)clinical arthritis in RA patients. 相似文献286.
287.
Marrero AR Silva-Junior WA Bravi CM Hutz MH Petzl-Erler ML Ruiz-Linares A Salzano FM Bortolini MC 《American journal of physical anthropology》2007,132(2):301-310
A total of 278 individuals from two Brazilian Indian tribes (Guarani and Kaingang) living in five different localities had their mitochondrial DNA sequenced for the first hypervariable segment (HVS-I), and a fraction of them was also studied for seven biallelic Y-chromosome polymorphisms. Nineteen HVS-I lineages were detected, which showed distinct distributions in the two tribes. The G(ST) value obtained with the mtDNA data is about 5 times higher for the Guarani as compared to the Kaingang, suggesting a higher level of differentiation between the three Guarani partialities than between the two Kaingang villages. Non-Amerindian admixture varied with sex and in the Guarani was only observed through the paternal line. Using these data and those of other Tupian and Jêan tribes, it was possible to make inferences about past migratory movements and the genetic differentiation of these populations. 相似文献
288.
The glycolytic proteins in plants are coded by small multigene families, which provide an interesting contrast to the high copy number of gene families studied to date. The alcohol dehydrogenase (Adh) genes encode glycolytic enzymes that have been characterized in some plant families. Although the amino acid sequences of zinc-containing long-chain ADHs are highly conserved, the metabolic function of this enzyme is variable. They also have different patterns of expression and are submitted to differences in nonsynonymous substitution rates between gene copies. It is possible that the Adh copies have been retained as a consequence of adaptative amino acid replacements which have conferred subtle changes in function. Phylogenetic analysis indicates that there have been a number of separate duplication events within angiosperms, and that genes labeled Adh1, Adh2 and Adh3 in different groups may not be homologous. Nonsynonymous/synonymous ratios yielded no signs of positive selection. However, the coefficients of functional divergence (theta) estimated between the Adh1 and Adh2 gene groups indicate statistically significant site-specific shift of evolutionary rates between them, as well as between those of different botanical families, suggesting that altered functional constraints may have taken place at some amino acid residues after their diversification. The theoretical three-dimensional structure of the alcohol dehydrogenase from Arabis blepharophylla was constructed and verified to be stereochemically valid. 相似文献
289.
290.
Job FM van Boven Eline Tommelein Koen Boussery Els Mehuys Stefan Vegter Guy GO Brusselle Maureen PMH Rutten-van M?lken Maarten J Postma 《Respiratory research》2014,15(1):66