Radical production by hydrogen peroxide/bicarbonate and copper uptake in mammalian cells: Modulation by Cu(II) complexes

AbstractThe presence of the bicarbonate/carbon dioxide pair is known to accelerate the transition metal ion-catalysed oxidation of various biotargets. It has been shown that stable Cu(II) complexes formed with imine ligands that allow redox cycling between Cu(I) and Cu(II) display diverse apoptotic effects on cell cultures. It is also reported that Cu(II)–tetraglycine can form a stable Cu(III) complex. In the present study, radical generation from H2O2 and H2O2/HCO3− in the presence of these two different classes of Cu(II) complexes was evaluated by monitoring the oxidation of dihydrorhodamine 123 and NADH and by the quantitative determination of thiobarbituric acid reactive substances (TBARs method). Cu(II)–imine complexes produced low levels of reactive species whereas Cu(II)–Gly-derived complexes, as well as the free Cu(II) ion, produced oxygen-derived radicals in significantly larger amounts. The effects of these two classes of complexes on mammalian tumour cell viability were equally distinct, in that Cu(II)–imine complexes caused apoptosis, entered in cell and remained almost unaffected in high levels whilst, at the same concentrations, Cu(II)–Gly peptide complexes and Cu(II) sulphate stimulated cell proliferation, with the cell managing copper efficiently. Taken together, these results highlight the different biological effects of Cu(II) complexes, some of which have been recently studied as anti-tumour drugs and radical system generators, and also update the effects of reactive oxygen species generation on cell cycle control

Purification, characterization and molecular cloning of the major chitinase from Tenebrio molitor larval midgut

Insect chitinases are involved in degradation of chitin from the exoskeleton cuticle or from midgut peritrophic membrane during molts. cDNAs coding for insect cuticular and gut chitinases were cloned, but only chitinases from moulting fluid were purified and characterized. In this study the major digestive chitinase from T. molitor midgut (TmChi) was purified to homogeneity, characterized and sequenced after cDNA cloning. TmChi is secreted by midgut epithelial cells, has a molecular weight of 44 kDa and is unstable in the presence of midgut proteinases. TmChi shows strong substrate inhibition when acting on umbelliferyl-derivatives of chitobio- and chitotriosaccharides, but has normal Michaelis kinetics with the N-acetylglucosamine derivative as substrate. TmChi has very low activity against colloidal chitin, but effectively converts oligosaccharides to shorter fragments. The best substrate for TmChi is chitopentaose, with highest kcat/KM value. Sequence analysis and chemical modification experiments showed that the TmChi active site contains carboxylic groups and a tryptophane, which are known to be important for catalysis in family 18 chitinases. Modification with p-hidroximercuribenzoate of a cysteine residue, which is exposed after substrate binding, leads to complete inactivation of the enzyme. TmChi mRNA encodes a signal peptide plus a protein with 37 kDa and high similarity with other insect chitinases from family 18. Surprisingly, this gene does not encode the C-terminal Ser-Thr-rich connector and chitin-binding domain normally present in chitinases. The special features of TmChi probably result from its adaptation to digest chitin-rich food without damaging the peritrophic membrane. © 2006 Elsevier Ltd. All rights reserved

Resposta do milho a fontes e modos de aplicação de fosforo durante três cultivos sucessivos em solo da região do cerrado.

Objetivou-se comparar fertilizantes fosfatados em diferentes modos de aplicação, durante três cultivos sucessivos de milho, num Argissolo Vermelho já adubado anteriormente. Foi utilizado um fatorial 4 x 2+1, envolvendo quatro fontes de P (superfosfato triplo - ST, termofosfato magnesiano - TM, fosfato reativo de Arad - FR e fosfato natural de Araxá - FA), duas formas de aplicação (a lanço ou no sulco de plantio), e uma testemunha (sem P) como tratamento adicional. Foram fornecidos 180 kg ha-1 de P7O5 no primeiro cultivo, com base nos teores totais das fontes. Para os cultivos seguintes, não foi feito preparo do solo. Determinaram-se os teores de nutrientes no solo e nas folhas de milho e a produção de grãos. As respostas aos tratamentos foram mais discrepantes inicialmente e tenderam à eqüidade com os cultivos sucessivos. Nas duas primeiras safras, as fontes de maior solubilidade (ST e TM) ocasionaram as maiores produções. Os fosfatos naturais (FR e FA) apresentaram aumento de eficiência com o tempo. A aplicação localizada do FR proporcionou alta produtividade na terceira safra. O residual de antigas adubações e as condições climáticas influenciaram os efeitos dos tratamentos

Influence of the body mass and visceral adiposity on glucose metabolism in obese women with Pro12Pro genotype in PPARgamma2 gene.

Introduction: Glucose metabolism may be altered in obesity and genotype for PPAR 2 can influence this variable. Objective: To evaluate the influence of body mass (BM) and visceral adiposity (VA) in glucose metabolism in morbid obese women with Pro12Pro genotype. Methods: Were selected 25 morbidly obese women. Groups were formed according to body mass index (BMI) [G1: 40-45 kg/m2 (n = 17); G2: > 45 kg/m2 (n = 8)]. Anthropometric, glycemia and insulinemia assessments (fasting, 60 and 120 minutes after high polyunsaturated fatty acids meal) were carried out. The insulin resistance (IR) and insulin sensitivity (IS) were assessed by HOMA-IR and QUICKI respectively. Results: G2 had higher BMI and waist circumference, compared to G1, impaired fasting glucose, low IS and higher IR. The postprandial glucose was normal, but there was a higher insulin peak one hour after the meal in G2. Conclusion: Increased BM and VA were associated with worse glucose metabolism suggesting metabolic differences between morbid obese with Pro12Pro genotype

Genetic characterization of Indubrasil cattle breed population.

Abstract The Indubrasil breed was developed in the Brazilian region called Triângulo Mineiro as a result of a cross between zebu cattle. Initially, it was used as a terminal cross and currently it represents approximately 4.45% of all the Brazilian zebu cattle. Studies were conducted to estimate genetic parameters in the Indubrasil using pedigree information, however, until now, no study has been developed using large-scale genomic markers in this breed. Pedigree information are widely used to investigate population parameters; however, they can neglect some estimates when compared to the use of genomic markers. Therefore, the objective of this study was to investigate the population structure and the genetic diversity of Indubrasil cattle using a high-density Single Nucleotide Polymorphism (SNP) panel (Illumina BovineHD BeadChip 700k). Levels of genomic homozygosity were evaluated using three different approaches: Runs of homozygosity (FROH), % of homozygosis (FSNP), and inbreeding coefficient (Fx). Further, Runs of Homozygosity (ROH) segments conserved among the animals were investigated to identify possible regions associated with the breed characteristics. Our results indicate that even the Indubrasil breed having a small effective population size, the levels of homozygosity (FROH = 0.046) are still small. This was possibly caused by the cross conducted among different breeds for its development. It suggests no immediate risks associated with loss of genetic variation. This information might be used in breeding programs, for the breed conservation and for the expansion of the Indubrasil breed

Variation at the NFATC2 Locus Increases the Risk of Thiazolidinedione-Induced Edema in the Diabetes REduction Assessment with ramipril and rosiglitazone Medication (DREAM) Study

Objective: Thiazolidinediones are used to treat type 2 diabetes. Their use has been associated with peripheral edema and congestive heart failure - outcomes that may have a genetic etiology. Research Design and Methods: We genotyped 4,197 participants of the multiethnic DREAM (Diabetes Reduction Assessment with ramipril and rosiglitazone Medication) trial with a 50k single nucleotide polymorphisms (SNP) array, which captures ∼2000 cardiovascular, inflammatory, and metabolic genes. We tested 32,088 SNPs for an association with edema among Europeans who received rosiglitazone (n = 965). Results: One SNP, rs6123045, in NFATC2 was significantly associated with edema (odds ratio 1.89 [95% CI 1.47-2.42]; P = 5.32 × 10-7, corrected P = 0.017). Homozygous individuals had the highest edema rate (hazard ratio 2.89, P = 4.22 × 10-4) when compared with individuals homozygous for the protective allele, with heterozygous individuals having an intermediate risk. The interaction between the SNP and rosiglitazone for edema was significant (P = 7.68 × 10-3). Six SNPs in NFATC2 were significant in both Europeans and Latin Americans (P < 0.05). Conclusions: Genetic variation at the NFATC2 locus contributes to edema among individuals who receive rosiglitazone