Purple acid phosphatases (PAPs) are a group of metallohydrolases that contain a dinuclear Fe III M II center (M II = Fe, Mn, Zn) in the active site and are able to catalyze the hydrolysis of a variety of phosphoric acid esters. The dinuclearhas recently been prepared and is found to closely mimic the coordination environment of the Fe III Zn II active site found in red kidney bean PAP (Neves et al. J. Am. Chem. Soc. 2007, 129, 7486). The biomimetic shows significant catalytic activity in hydrolytic reactions. By using a variety of structural, spectroscopic, and computational techniques the electronic structure of the Fe III center of this biomimetic complex was determined. In the solid state the electronic ground state reflects the rhombically distorted Fe III N 2 O 4 octahedron with a dominant tetragonal compression aligned along the μ-OH-Fe-O phenolate direction. To probe the role of the Fe-O phenolate bond, the phenolate moiety was modified to contain electron-donating or -withdrawing groups (-CH 3 , -H, -Br, -NO 2 ) in the 5-position. The effects of the substituents on the electronic properties of the biomimetic complexes were studied with a range of experimental and computational techniques. This study establishes benchmarks against accurate crystallographic structural information using spectroscopic techniques that are not restricted to single crystals. Kinetic studies on the hydrolysis reaction revealed that the phosphodiesterase activity increases in the order -NO 2 rBr rH rCH 3 when 2,4-bis(dinitrophenyl)phosphate (2,4-bdnpp) was used as substrate, and a linear free energy relationship is found when log(k cat /k 0 ) is plotted against the Hammett parameter σ. However, nuclease activity measurements in the cleavage of double stranded DNA showed that the complexes containing the electron-withdrawing -NO 2 and electron-donating -CH 3 groups are the most active while the cytotoxic activity of the biomimetics on leukemia and lung tumoral cells is highest for complexes with electron-donating groups.

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Dietary patterns before pregnancy may be associated with depressive symptomatology during pregnancy. The aim of this study was to identify dietary patterns before pregnancy and to examine the association between these dietary patterns and depressive symptoms during pregnancy. A prospective cohort of 248 healthy pregnant women were followed at 5-13, 20-26, and 30-36 gestational weeks. Dietary intake was obtained by using a food-frequency questionnaire administered between 5 and 13 gestational weeks, which referred to the 6 mo preceding gestation, and factor analysis (principal components) was applied to identify dietary patterns. The Edinburgh Postnatal Depressive Scale (EPDS) was used to evaluate depressive symptoms during 3 follow-up pregnancy points. A multiple linear mixed-effects model was applied to verify the association between dietary patterns and depressive symptoms adjusted for obstetric factors, socioeconomic status, and energy intake. Three prepregnancy dietary patterns were identified: common-Brazilian, healthy, and processed. Together, these patterns explained 36.1% of the total percentage of variance; the eigenvalues were 2.88, 2.12, and 1.86, respectively. Mean depressive symptom scores were 9.0 (95% CI: 8.4, 9.6), 7.2 (95% CI: 6.5, 7.8), and 7.0 (95% CI: 6.4, 7.7) for trimesters 1, 2, and 3, respectively. The rate of decrease in depressive symptoms was -0.088/wk (95% CI: -0.115, -0.061; P < 0.001). In the multiple longitudinal linear regression model, the healthy dietary pattern before pregnancy was inversely associated with depressive symptoms (β:-0.723; 95% CI: -1.277, -0.169; P = 0.011). High adherence to the healthy pattern before pregnancy was associated with lower EPDS scores during pregnancy in women from Rio de Janeiro, Brazil.

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Recebido em 7/8/01; aceito em 2/4/02 SIDEROPHORES: "A MICROORGANISM'S ANSWER". Siderophores (from the Greek: "iron carriers") are defined as relatively low molecular weight, ferric ion specific chelating agents elaborated by microorganisms growing under low iron stress. The role of these compounds is to scavenge iron from the environment and to make this essential chemical element available to the microbial cell. The present paper is a brief presentation of siderophore coordination chemistry with emphasis on those aspects relevant to the transportation of iron (III) complexes across biological membranes. Finally, the role of siderophores in infection and their clinical potential as iron scavenging molecules are reviewed.