Changes in amniotic fluid and umbilical cord serum proteomic profiles of foetuses with intrauterine growth retardation

Foetal growth is a result of a complex net of processes, requiring coordination within the maternal, placental, and foetal compartments, the imbalance or lack of which may lead to intrauterine growth restriction (IUGR). IUGR is the major cause of perinatal morbidity and mortality, and is also related to enhanced morbidity and metabolic abnormalities later in life. In the present study, the protein profiles of umbilical cord serum (UCS) and amniotic fluid (AF) of ten IUGR and ten appropriate for gestational age newborns have been analysed by 2-DE, and nanoHPLC-Chip/MS technology. A total of 18 and 13 spots were found to be differentially expressed (p<0.01) in UCS and AF respectively. The unique differentially expressed proteins identified by MS/MS analysis were 14 in UCS, and 11 in AF samples. Protein gene ontology classification indicate that 21% of proteins are involved in inflammatory response, 20% in immune response, while a smaller proportion are related to transport, blood pressure, and coagulation. These results support the conclusion that the IUGR condition alters the expression of proteins involved in the coagulation process, immune mechanisms, blood pressure and iron and copper homeostasis control, offering a new insight into IUGR pathogenesis.     

Preparation and photophysical studies of a fluorous phase-soluble fullerene derivative

We report the first synthesis of a well-characterized "Teflon ponytail" fullerene adduct (3) via the Hirsch-Bingel reaction with a malonate bearing two perfluorinated alkyl chains. This C3 tris-adduct shows excellent solubility in perfluorinated solvents, such as FC-72 and FC-75. Compound 3 was found to be an efficient sensitizer for singlet oxygen formation in fluorous media, which has potential in biphasic systems and in photobiology.     

Solid State Structures of AsCl5 and SbCl5

Arsenic pentachloride has a trigonal bipyramidal structure in the solid state with As‐Cl_eq = 210.6, 211.9 pm, As‐Cl_ax= 220.7 pm, space group Pmmn, a = 706.2 (1); b = 760.3 (2), c = 623.3 (1) pm. Antimony pentachloride exists in two modifications: above −54.1 °C it is also trigonal bipyramidal with Sb‐Cl_eq = 227.0 and Sb‐Cl_ax = 233.3 pm, space group P6₃/mmc, a = 741.4 (1), c = 799.0(2)pm. Below −54.1 °C it changes reversibly into a double chlorine bridged dimer resulting in an edge shared double octahedral structure, space group P2₁/c, a = 952.4 (1), b = 1189.9 (1), c = 1219.7 (1) pm, β = 108, 27 (1): In presence of water the formation of AsCl₅ is hindered, two salts containing the octahedral anion AsCl₆⁻ have been isolated, [(H₅O₂⁺)₅AsCl₆⁻(Cl⁻)₄], space group C2/c, a= 1416.9 (2), b = 1316.6 (3), c = 1215.3 (2) pm, β; = 94.96 (1)°, and [(H₅O₂⁺)(AsCl₆⁻)·AsOCl₃], space group P2₁/n, a = 771.6 (3), b = 904.5 (3), c = 2140.7(2)pm, β = 100.21(1). The AsOCl₃ moiety in this compound appears as a monomer, in contrast to pure AsOCl₃, which is a doubly oxygen bridged dimer in the solid state.     

New Polymers from Natural Phenols Using Horseradish or Soybean Peroxidase

The flavonol quercetin, its glycoside rutin, the flavanol catechin, the isoflavone daidzein and 5,6,4′‐trihydroxyisoflavone can be oxidatively polymerized via a radical polyrecombination mechanism catalyzed by horseradish or soybean peroxidase in a mixture of phosphate buffer (pH 7) and 1,4‐dioxane. The average molecular weights of the polymers were found to be in the range 4 000–12 000 g/mol. Daidzein derivatives with a methoxy (formononetin) or nitro group or a hydrogen atom at C‐4′ could not be polymerized under these conditions. These results and molecular modeling studies suggest that polymerization preferentially occurs via the electron‐rich ring B of the isoflavonoids. The polymers were characterized by means of FT‐IR and UV spectroscopy, and their redox behavior was analyzed using cyclic voltammetry.     

Cyclic Voltammetric Study of Some Anti‐Chagas‐Active 1,4‐Dioxidoquinoxalin‐2‐yl Ketone Derivatives

The electrochemical properties of 24 1,4‐dioxidoquinoxalin‐2‐yl ketone derivatives with varying degrees of anti‐Chagas activity were investigated in the aprotic solvent dimethylformamide (DMF) by cyclic voltammetry and first‐derivative cyclic voltammetry. For this group of compounds, the first reduction in DMF was either reversible or quasireversible and consistent with reduction of the N‐oxide functionality to form the radical anion. The second reduction process for these compounds was irreversible under the conditions used. The reduction potentials correlated well with molecular structure. Substitution in the 3‐, 6‐, and 7‐ positions of the quinoxaline ring by electron‐withdrawing substituents directly affected the ease of reduction and improved the biological activities of these compounds, whereas substitution by electron‐donating groups had the opposite effect. The electrochemical results, when combined with previous work on their mechanism of action against Chagas disease and their measured anti‐Chagas activities, indicated that the quinoxaline 1,4‐dioxide system serves as a promising starting point for chemical modifications aimed at improving the T. cruzi activity via a possible bioreduction mechanism.     

Hybrid iodoperfluoroalkane-ferrocene supramolecular arrays: the shortest contacts iodine forms with nitrogen atoms and unsaturated moieties

α,ω-Diiodoperfluoralkanes self-assemble in solution and in the solid phase with (S)-(−)-N,N-dimethyl-1-ferrocenylethylamine. The formed adducts have been characterized by DSC, IR, Raman, and NMR techniques. Single crystal X-ray analysis of one of the obtained adducts shows that perfluorinated and organometallic modules alternate giving rise to infinite one-dimensional (1D) chains. The interacting modules are connected through strong n-type halogen bondings, involving nitrogen and iodine atoms, and weak π-type halogen bondings, involving Cp rings and iodine atoms. Both interactions are the shortest reported to now in their respective classes. Theoretical calculations have been performed to quantify the observed π-type halogen bonding. For the first time a metallocene-perfluorocarbon (PFC) hybrid material is described.     

Kinetics and mechanism of the reaction of CF3 radicals with NO2

The reaction of CF₃ with NO₂ was studied at 296 ± 2K using two different absolute techniques. Absolute rate constants of (1.6 ± 0.3) × 10⁻¹¹ and (2.1 _−0.3⁺⁰⁷) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ were derived by IR fluorescence and UV absorption spectroscopy, respectively. The reaction proceeds via two reaction channels: CF₃ + NO₂ → CF₂O + FNO, (70 ± 12)% and CF₃ + NO₂ → CF₃O + NO, (30 ± 12)%. An upper limit of 11% for formation of other reaction products was determined. The overall rate constant was within the uncertainty independent of total pressure between 0.4 to 760 torr. © 1996 John Wiley & Sons, Inc.     

Biosynthesis of poly-β-hydroxybutyrate and exopolysaccharides on azotobacter chroococcum strain 6B utilizing simple and complex carbon sources

Coproduction of poly-β-hydroxybutyrate (PHB) and exopolysaccharides (EPS) was investigated with Azotobacter chroococcum strain 6B isolated from soil samples. The bacterium was cultured using various carbon sources solely or with 0.1 g/L of ammonium sulfate. Ammonium addition resulted in reduced PHB and EPS production with glucose, fructose, and sucrose media, but cellular mass remained constant except for sucrose. Protein was nearly twofold higher in ammonium-grown cultures. Glucose and fructose alone biosynthesized high amounts of EPS (maximum 2.1 and 1.1 g/L, respectively, at 72 h), whereas PHB was accumulated only in glucose-grown cells. Sucrose almost did not produce EPS. Conversely, PHB content was the highest obtained from all experimented conditions (1.1 g/L at 48 h, 40% cell dry wt). When a complex carbon source such as sugar cane molasses was utilized, PHB was accumulated concomitant with EPS production from the initial time to 48 h (0.75 g/L, 37% cell dry wt and 0.6 g/L, respectively), and then PHB decayed at 72 h (0.2 g/L). On the other hand, EPS continued to be biosynthesized (1.1 g/L, 72 h). PHB fractions of total intra- and extracellular biopolymers were calculated. Sucrose-modified Burk’s medium without ammonium addition is suggested as a medium capable of diverting the carbon source for the production of intracellular PHB rather than EPS with A. chroococcum 6B.     

THE KINETICS OF THE EARLY STAGES OF THE PHYTOCHROME PHOTOTRANSFORMATION Pr→ Pfr. A COMPARATIVE STUDY OF SMALL (60 kDalton) and NATIVE (124 kDalton) PHYTOCHROMES FROM OAT

A comparative study of the decay kinetics of photogenerated transients from small (60 kDalton) and native (124 kDalton) oat phytochrome in the red-absorbing form (P_r) in phosphate buffer containing 5 mM ethylenediamine tetraacetic acid, pH 7.8, (PB) and in PB containing 20% ethylene glycol, has been carried out in the temperature range 275–298 K. The analysis confirmed that at least two primary photoproducts, intermediates Iⁱ₇₀₀s and Iⁱ_7oo are formed from P_r. The kinetic parameters, as observed in PB at 695 nm and 275 K, are similar for the I₇₀₀ intermediates of both small and native phytochrome. Namely, the lifetimes are about 21 μs (component percentages 38%) for the I Iⁱ₇₀₀s and about 200 μ.s (62%) for the Iⁱ₇₀₀S- Arrhenius preexponential factors (A) of about 10¹⁶ and 10¹⁵ s-¹and activation energies of about 61 and 56 kJ/mol were measured for the absorbance decays of the I₇₀₀S of small and native phytochrome, respectively. The kinetic data favour parallel paths for the formation of the Iⁱ₇₀₀s from P_r, and the activation parameters indicate that the primary photoreactions of the transformation from P_r to the far-red-absorbing form are restricted to the chromophore within the protein. Moreover, the relatively modest temperature dependence of the lifetimes of the Iⁱ₇₀₀^S from small and native P_r supports the working hypothesis that the ground state reactions to the Iⁱ_bl, intermediates–although somewhat influenced by the polypeptide fragment that is removed upon degradation of native to small P_r–are localized to the chromophore, as is most probably the case also for the primary photoreactions. The effect of the addition of 20% ethylene glycol on the pre-exponential factors of the time-dependent decay functions is discussed in similar terms of the early stages of the phototransformation.     

H2S Dosimetry by CuO: Towards Stable Sensors by Unravelling the Underlying Solid-State Chemistry

The precise detection of the toxic gas H₂S requires reliable sensitivity and specificity of sensors even at minute concentrations of as low as 10 ppm, the value corresponding to typical exposure limits. CuO can be used for H₂S dosimetry, based on the formation of conductive CuS and the concomitant significant increase in conductance. In theory, at elevated temperature the reaction is reversed and CuO is formed, ideally enabling repeated and long-term use of one sensor. Yet, the performance of CuO tends to drop upon cycling. Utilizing defined CuO nanorods we thoroughly elucidated the associated detrimental chemical changes directly on the sensors, by Raman and electron microscopy analysis of each step during sensing (CuO→CuS) and regeneration (CuS→CuO) cycles. We find the decrease in the sensing performance is mainly caused by the irreversible formation of CuSO₄ during regeneration. The findings allowed us to develop strategies to reduce CuSO₄ formation and thus to substantially maintain the sensing stability even for repeated cycles. We achieved CuO-based dosimeters possessing a response time of a few minutes only, even for 10 ppm H₂S, and prolonged life-time.