Role of the Ca-pectates on the accumulation of heavy metals in the root apoplasm

In order to better understand the processes that regulate the accumulation in the apoplasm of heavy metals and their mobilization by the plant metabolites it is essential to study the mechanisms that regulate the interactions between metal ions and pectins. In such a context, the sorption of Cd(II), Zn(II), Cu(II) and Pb(II) from single and multi-metal solutions, by a Ca-polygalacturonate gel with a degree of esterification of 18.0 (PGAM₁) and 65.5% (PGAM₂) was studied in the 3.0–6.0 pH range in the presence of CaCl₂ 2.5 mM. The sorption of Cr(III) from single metal solution was also considered. The results show that the amount of each metal ion sorbed increases with increasing the initial metal ion concentration and pH. The data from the single metal solution tests show that at pH 6.0 the affinity of the metal ions towards the PGAM₁ matrix follows the order: Cr(III) > Cu(II) ? Pb(II) ? Zn(II) ? Cd(II). The simultaneous sorption of the bivalent metal ions by the PGAM₁ gels indicates that Pb(II) is selectively sorbed. The FT-IR spectra show that the carboxylate groups are mainly responsible for the metal ion coordination. The ability of PGAM₂ to accumulate Cr(III), Cu(II), and Pb(II) was lower than that found in the PGAM₁ systems whereas the sorption of Zn(II) and Cd(II) was negligible.     

A ratiometric fluorescent detection of Zn(II) in aqueous solutions using pyrene-appended histidine

A fluorescent chemosensor, Py-His, based on histidine was easily synthesized in solid phase synthesis. Py-His displayed a highly sensitive ratiometric response to Zn(II) with potent binding affinity (K_a = 1.17 × 10¹³ M^?2) in aqueous solutions. The detection limit of Py-His for Zn(II) was calculated as 80.8 nM. Moreover, Py-His distinguished Zn(II) and Hg(II) by different ratiometric response type; the chemosensor showed a more enhanced increase of excimer emission intensity to Zn(II) than Hg(II). Upon addition of Ag(I) and Cu(II), Py-His showed a turn-off response mainly due to the quenching effect of these metal ions. The binding stoichiometry (2:1 or 1:1) of Py-His to target metal ions played a critical role in the fluorescent response type (ratiometric and turn off response) to target metal ions. The role of imidazole group of Py-His for ratiometric detection of Zn(II) was proposed by pH titration experiments.     

Removal of Zn(II) ions from aqueous solution using Moringa oleifera Lam. (horseradish tree) biomass

The removal of Zn(II) ions from aqueous solution using pure and chemically pretreated biomass of Moringa oleifera was investigated at 30 ± 1 °C in this study. The experimental results explored that the maximum pH (pH_max) for efficient sorption of Zn(II) was 7 ± 0.1 at which evaluated biosorbent dosage and biosorbent particle size, were 0.5 g/L, <0.255 mm, respectively. The cellular Zn(II) concentration increased with the concentrations of Zn(II) in solution. Pretreatment of M. oleifera biomass affected the sorption process and the uptake capacity (mg/g) of biomass for Zn(II) uptake was in following order: NaOH (45.76) > H₂SO₄ (45.00) > CTAB (42.80) > Ca(OH)₂ (42.60) > Triton X-100 (42.06) > H₃PO₄ (41.22) > Al(OH)₃ (41.06) > SDS (40.41) > HCl (37.00) > non-treated biomass (36.07). There was significant increase in uptake capacity of M. oleifera biomass, which suggested that affinity between metal and sorbent can be increased after some sort of pretreatment. Both Langmuir and Freundlich isotherm model fitted well to data of Zn(II) biosorption as represented by high value of their correlation coefficient (i.e. R² ≈ 1). Kinetic studies revealed that Zn(II) uptake was fast with 90% or more of uptake occurring with in 40 min of contact time and the equilibrium was reached in 50 min of contact time. The sorption rates were better described by a second order expression than by a more commonly applied Lagergren equation. Finally it was concluded that pretreatment of M. oleifera biomass can achieve superior Zn(II) uptake capacity in comparison to non-pretreated biomass.     

Synthesis,X-ray structures,and magnetic properties of heterometal dinuclear Cr(III)–M(II) complexes

New 3,5-bis(2-pyridyl)pyrazolato (bpypz) bridged heterometal dinuclear complexes [(nta)Cr(μ-bpypz)M^II(picen)]⁺ (M = Mn(II), Ni(II)) and [(acac)₂Cr(μ-bpypz)Ni^II(picen)]²⁺ (nta = nitrilotriacetate, picen = N,N′-bis(2-pyridylmethyl)ethylenediamine, acac = acetylacetate) were synthesized and characterized by the X-ray analysis, ESI-MS and the magnetic measurements, and/or ²H NMR spectra. The molecular structures were compared from a viewpoint of the conformation of the picen depending on M^II ionic radii or different modes of hydrogen bonds. The picen in [(nta)Cr(μ-bpypz)Mn^II(picen)]BF₄ takes an abnormal conformation with intramolecular bifurcated three-center hydrogen bonds between two carboxylate oxygens of nta and an amine proton of the picen as found for the previously reported corresponding Fe(II) complex [K. Ni-iya, A. Fuyuhiro, T. Yagi, S. Nasu, K. Kuzushita, S. Morimoto, S. Kaizaki, Bull. Chem. Soc. Jpn. 74 (2001) 1891]. On the other hand, for both Ni(II)-nta and Ni(II)-acac complexes, the picen takes a normal conformation with only a two-center hydrogen bond between non-bridging ligands. The magneto-structural relation is discussed for the Cr(III)–Ni(II) complexes in connection with the orthogonality or orbital overlap arising from the difference in distortion around Cr(III) moiety.     

Effect of ligand congeniality on energy transfer reaction between photo-excited tris(bipyridine)ruthenium(II) and chromate(III) complexes in aqueous solutions

Energy-transfer rate-constants from photo-excited [Ru(N–N)₃]²⁺ (N–N = 2,2′-bipyridine (bpy), 4,4′-dimethyl-2,2′-bipyridine (4dmb), 5,5′-dimethyl-2,2′-bipyridine (5dmb)) to [Cr(O–O)₃]³⁻ (O–O²⁻ = ox²⁻ ((COO⁻)₂), mal²⁻ (CH₂(COO⁻)₂)) and [Cr(CN)₆]³⁻ in encounter complexes were evaluated in aqueous solutions containing alkali metal ion. The rate constant depends on the molecular size of the ruthenium(II) complex: 1.8 × 10⁸ s⁻¹ for [Ru(bpy)₃]²⁺ (molecular radius, r = 5.8 Å), 1.4 × 10⁸ s⁻¹ for [Ru(5dmb)₃]²⁺ (r = 6.1 Å) and 0.96 × 10⁸ s⁻¹ for [Ru(4dmb)₃]²⁺ (r = 6.7 Å) in the system of [Ru(N–N)₃]²⁺–[Cr(ox)₃]³⁻ in aqueous solution. However, the rate constant is much more sensitive to the chromate(III) complex than to ruthenium(II) complex; 1.8 × 10⁸ s⁻¹ and 0.43 × 10⁸ s⁻¹ for [Cr(ox)₃]³⁻ (r = 4.0 Å) and [Cr(mal)₃]³⁻ (r = 4.2 Å) in the [Ru(bpy)₃]²⁺–[Cr(O–O)₃]³⁻ systems, respectively. We conclude that the congeniality between the donor’s and acceptor’s ligands in encounter complex plays an important role in energy transfer in aqueous solution.     

Carbonic anhydrase inhibitors. Inhibition of the human cytosolic isoforms I and II and transmembrane,tumor-associated isoforms IX and XII with boronic acids

A series of aromatic, arylalkenyl- and arylalkyl boronic acids were assayed as inhibitors of four physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isoforms, the cytosolic human (h) hCA I and II, and the transmembrane, tumor-associated hCA IX and XII. The best hCA I and II inhibitor was biphenyl boronic acid with, a K_I of 3.7–4.5 μM, whereas the remaining derivatives showed inhibition constants in the range of 6.0–1560 μM for hCA I and of 6.0–1050 μM for hCA II, respectively. hCA IX and XII were effectively inhibited by most of the aromatic boronic acids (K_Is of 7.6–12.3 μM) whereas the arylalkenyl and aryl–alkyl derivatives generally showed weaker inhibitory properties (K_Is of 34–531 μM). The nature of the moiety substituting the boronic acid group strongly influenced the CA inhibitory activity, with inhibitors possessing low micromolar to millimolar activity being detected in this small series of investigated compounds. This study proves that the B(OH)₂ moiety represents a new zinc-binding group for the generation of effective CA inhibitors targeting isoforms with medicinal chemistry applications. The boronic acids probably bind to the Zn(II) ion within the CA active site leading to a tetrahedral geometry of the metal ion and of the B(III) derivative.     

Chromium(III) tris(picolinate) is mutagenic at the hypoxanthine (guanine) phosphoribosyltransferase locus in Chinese hamster ovary cells

Chromium trispicolinate (CrPic) is a popular dietary supplement that is not regulated by the Food and Drug Administration. We are using this compound as a bio-available model to explore the role of Cr(III) in Cr(VI)-induced cancers. The ability of CrPic to cause mutations at the hypoxanthine (guanine) phosphoribosyltransferase (hprt) locus of CHO AA8 cells has been measured after a 48 h exposure. The highest dose tested was 80 μg/cm² CrPic, which, if fully soluble, would be equivalent to 1 mM or 0.44 mg/ml CrPic, and would correspond to 1 mM Cr(III) or 52 μg/ml Cr(III). This exposure resulted in 68±16% cell survival based on 48 h cell counts, and 24±11% survival by 7-day colony formation. Exposure of CHO cells to CrPic produced a statistically significant increase in 6-thioguanine (6-TG)-resistant cells over the dose range tested. The 80 μg/cm² CrPic exposure resulted in an average induced mutation frequency (MF) of 58 per 10⁶ surviving cells, or an average 40-fold increase in hprt mutants relative to untreated cells. An equivalent dose of 3 mM Pic was highly cytotoxic and did not yield hprt mutants. The dose range of 0.375–1.5 mM Pic produced a slight increase in hprt mutants, but the increase was not statistically significant. An equivalent dose of 1 mM chromic chloride yielded an induced MF of 9 per 10⁶ surviving cells, or a 10-fold increase in mutants with cell survivals of >100%. The coordination of Cr(III) with picolinic acid may make the metal more genotoxic than other forms of Cr(III). In light of the current results and the known ability of Cr(III) and CrPic to accumulate in tissues, as well as the growing evidence of Cr(III) involvement in Cr(VI)-induced cancers, we caution against ingestion of large doses of CrPic for extended periods.     

Comparative serum albumin interactions and antitumor effects of Au(III) and Ga(III) ions

In the present study, interactions of Au(III) and Ga(III) ions on human serum albumin (HSA) were studied comparatively via spectroscopic and thermal analysis methods: UV–vis absorbance spectroscopy, fluorescence spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and isothermal titration calorimetry (ITC). The potential antitumor effects of these ions were studied on MCF-7 cells via Alamar blue assay. It was found that both Au(III) and Ga(III) ions can interact with HSA, however; Au(III) ions interact with HSA more favorably and with a higher affinity. FT-IR second derivative analysis results demonstrated that, high concentrations of both metal ions led to a considerable decrease in the α-helix content of HSA; while Au(III) led to around 5% of decrease in the α-helix content at 200 μM, it was around 1% for Ga(III) at the same concentration. Calorimetric analysis gave the binding kinetics of metal–HSA interactions; while the binding affinity (K_a) of Au(III)–HSA binding was around 3.87 × 10⁵ M⁻¹, it was around 9.68 × 10³ M⁻¹ for Ga(III)–HSA binding. Spectroscopy studies overall suggest that both metal ions have significant effects on the chemical structure of HSA, including the secondary structure alterations. Antitumor activity studies on MCF7 tumor cell line with both metal ions revealed that, Au(III) ions have a higher antiproliferative activity compared to Ga(III) ions.     

Isostructural M(RL)2(hfac)2 complexes with RL = 5-(4-[N-tert-butyl-N-aminoxyl]phenyl)pyrimidine

5-(4-(N-tert-Butyl-N-aminoxylphenyl))pyrimidine (RL, 4PPN) forms crystallographically isostructural and isomorphic pseudo-octahedral M(RL)₂(hfac)₂ complexes with M(hfac)₂, M = Zn, Cu, Ni, Co, and Mn. Multiple close contacts occur between sites of significant spin density of the organic radical units. Magnetic behavior of the Zn, Cu, Ni, Co complexes appears to involve multiple exchange pathways, with multiple close crystallographic contacts between sites that EPR (of 4PPN) indicates to have observable spin density. Powder EPR spectra at room temperature and low temperature are reported for each complex. Near room temperature, the magnetic moments of the complexes are roughly equal to those expected by a sum of non-interacting moments (two radicals plus ion). As temperature decreases, AFM exchange interactions become evident in all of the complexes. The closest fits to the magnetic data were found for a 1-D Heisenberg AFM chain model in the Zn(II) complex (J/k = (?)7 K), and for three-spin RL—M—RL exchange in the other complexes (J/k = (?)26 K, (?)3 K, (?)6 K, for Cu(II), Ni(II), and Co(II) complexes, respectively).     

Heavy metal bioaccumulation by the organs of Phragmites australis (common reed) and their potential use as contamination indicators

The concentrations of heavy metals in the roots, rhizomes, stems and leaves of the aquatic macrophyte Phragmites australis (common reed), and in the corresponding water and sediment samples from the mouth area of the Imera Meridionale River (Sicily, Italy), were investigated to ascertain whether plant organs are characterized by differential accumulation, and to test the suitability of the various organs for heavy metal biomonitoring of water and soil. Heavy metals considered were Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn. Results showed that belowground organs were the primary areas of metal accumulation. In particular, metal concentrations in plant organs decreased in the order of root > rhizome ≥ leaf > stem. All four organs showed significant differences in concentration for Cr, Hg, Mn, Zn, thus suggesting low mobility from roots to rhizomes and to aboveground organs. Although the organs followed different decreasing trends of metal concentration, the trend Mn > Zn > Pb > Cu was found in each plant organ. Mn showed the highest concentrations in all organs whereas the lowest concentrations regarded Cd and Cr in the belowground and aboveground organs, respectively. The toxic threshold was exceeded by Cr in roots, rhizomes and leaves, Mn in roots and leaves, Ni in roots. The highest average concentrations were found as follows: Cd, Hg, Pb, Zn in root, Cr, Mn, Ni in sediment, Cu in water. Positive linear relationships were found between heavy metal concentrations in all plant organs and those in water and sediment, thus indicating the potential use of such organs for pollution monitoring of water and sediment. Advantages of using plant species as biomonitors, especially Phragmites australis, were also discussed.     

Effect of partial replacement of concentrates with jackfruit (Artocarpus heterophyllus) leaves on growth performance of kids grazing on native pasture of Tripura,India

Fifteen Black Bengal kids of about 3 months of age and body weight ranging from 3.8 to 4.9 kg were randomly distributed into three groups of five. Kids grazed native pasture 8 h/d. The kids in group I received supplementary concentrate (maize 35%, mustard cake 32%, rice bran 30%, mineral mixture 2% and common salt 1%) at approximately 2% of BW. However, 25 and 50% of the concentrate was replaced with jackfruit leaves for groups II and III, respectively. Total dry matter intake (DMI) was significantly higher in groups II and III than for group I due to greater forage consumption. Digestibility of CP (P < 0.05) decreased and that of NDF increased (P < 0.01) with increasing level of jackfruit leaves in the diet. Digestibility of ADF (P < 0.01), hemi cellulose (P < 0.05) and cellulose (P < 0.01) was higher in groups II and III in comparison to group I. Ruminal pH and TVFA concentration were not significantly different among the groups; however, rumen ammonia-N concentration decreased (P < 0.01) with increased level of jackfruit leaves in the diet. Similarly, plasma urea nitrogen and blood glucose levels were also reduced (P < 0.05) with increasing level of jackfruit leaves in the diet Average daily gain (ADG) was 47.33, 45.11 and 35.56 g/d in groups I, II and III, respectively. ADG and DMI/kg gain were not adversely affected when the level of replacement was restricted to 25%; however, at the 50% of replacement both parameters were adversely affected (P < 0.05). From the results of this experiment, it was concluded that jackfruit leaves might replace 25% of the supplemental concentrate for growing kids grazing in native pasture of northeast India.     

Comparative efficiency of algal biofilters in the removal of chromium and copper from wastewater

The performance of a macroalgae (Sargassum sp.), a laboratory-cultivated microalgae (Chlorococcum sp.) and a commercially available granulated activated carbon (GAC) for the removal of copper (Cu) and chromium (Cr) from aqueous solutions was evaluated using batch experiments. Kinetic and isotherm experiments were done at the optimal pH of 4.5 ± 0.1 for Cu (II) and 2.0 ± 0.1 for Cr (total). The equilibrium isotherms were determined and the results were analyzed using the Langmuir and Freundlich models. The best Cu removal performance was observed on Sargassum at a maximum removal of 87.3% obtained for an initial concentration of 20 mg L^?1 Cu. The maximum uptake capacities for Cu (II) were 71.4, 19.3 and 11.4 mg g^?1 of Sargassum, Chlorococcum and GAC, respectively. The biosorbents were also able to remove appreciable amounts of Cr, again with Sargassum showing maximum uptake capacity over the other materials. Kinetic studies also reveal that the removal rate is faster for both metals in Sargassum. Tests with an actual wastewater confirm the maximum uptake capacity of Cu by Sargassum. In all experiments the Sargassum biofilter outperformed GAC, which makes it a promising low-cost alternative to conventional filtration materials for wastewater treatment.     

Calorimetric and spectroscopic investigations of the binding of metallated porphyrins to G-quadruplex DNA

BackgroundThe human telomere contains tandem repeat of (TTAGG) capable of forming a higher order DNA structure known as G-quadruplex. Porphyrin molecules such as TMPyP4 bind and stabilize G-quadruplex structure.MethodsIsothermal titration calorimetry (ITC), circular dichroism (CD), and mass spectroscopy (ESI/MS), were used to investigate the interactions between TMPyP4 and the Co(III), Ni(II), Cu(II), and Zn(II) complexes of TMPyP4 (e.g. Co(III)-TMPyP4) and a model human telomere G-quadruplex (hTel22) at or near physiologic ionic strength ([Na⁺] or [K⁺] ≈ 0.15 M).ResultsThe apo-TMPyP4, Ni(II)-TMPyP4, and Cu(II)-TMPyP4 all formed complexes having a saturation stoichiometry of 4:1, moles of ligand per mole of DNA. Binding of apo-TMPyP4, Ni(II)-TMPyP4, and Cu(II)-TMPyP4 is described by a “four-independent-sites model”. The two highest-affinity sites exhibit a K in the range of 10⁸ to 10¹⁰ M^− 1 with the two lower-affinity sites exhibiting a K in the range of 10⁴ to 10⁵ M^− 1. Binding of Co(III)-TMPyP4, and Zn(II)-TMPyP4, is best described by a “two-independent-sites model” in which only the end-stacking binding mode is observed with a K in the range of 10⁴ to 10⁵ M^− 1.ConclusionsIn the case of apo-TMPyP4, Ni(II)-TMPyP4, and Cu(II)-TMPyP4, the thermodynamic signatures for the two binding modes are consistent with an “end stacking” mechanism for the higher affinity binding mode and an “intercalation” mechanism for the lower affinity binding mode. In the case of Co(III)-TMPyP4 and Zn(II)-TMPyP4, both the lower affinity for the “end-stacking” mode and the loss of the intercalative mode for forming the 2:1 complexes with hTel22 are attributed to the preferred metal coordination geometry and the presence of axial ligands.General significanceThe preferred coordination geometry around the metal center strongly influences the energetics of the interactions between the metallated-TMPyP4 and the model human telomeric G-quadruplex. This article is part of a Special Issue entitled Microcalorimetry in the BioSciences — Principles and Applications, edited by Fadi Bou-Abdallah.     

On the crystal structures and magnetism of some hybrid organic–inorganic metal organophosphonates

We review our recent work in the field of molecule-based magnets showing the structural and magnetic properties of a special class of hybrid organic–inorganic compounds, i.e. metal(II) organophosphonates. The synthesis, the crystal structures and, in particular, the magnetic studies of selected examples of compounds of formulas M(II)[(R–PO₃)(H₂O)], and M₂[(O₃P–R′–PO₃)(2H₂O)] M = Cr, Fe, Co; R = C_nH_2n+1, n = 1, 2, 3… and C₆H₅, R′ = (CH₂)₂ prepared in our laboratory are presented and discussed. Metal alkylphosphonates, except those of Co(II), are weak ferromagnets at low temperatures. The observed magnetic ordering temperature T_N varies from 4.2 to 25 K, depending on the transition metal ions and on crystal and molecular structure. Moreover, in the case of a bifunctional molecule like aminoethylphosphonic acid, NH₂(CH₂)₂PO₃H₂, or the carboxyethylphosphonic acid, HO₂C(CH₂)₂PO₃H₂, is used as a ligand, then a novel Cr(II) compound of formula Cr[NH₃(CH₂)₂PO₃(Cl)(H₂O)] and a microporous Fe(III) salt (NH₄)[Fe₂(OH){O₃P(CH₂)₂CO₂}₂] are isolated. The latter are both polar and, more interesting, Cr(II) ammoniumethylphosphonate chloride results to be a weak ferromagnet below T_N = 5.0 K.     

Continuous Cr(VI) removal by Scenedesmus incrassatulus in an airlift photobioreactor

Cr(VI) removal by Scenedesmus incrassatulus was characterized in a continuous culture system using a split-cylinder internal-loop airlift photobioreactor fed continuously with a synthetic effluent containing 1.0 mg Cr(VI) l^?1 at dilution rate (D) of 0.3 d^?1. At steady state, there was a small increase (6%) on the dry biomass (DB) concentration of Cr(VI)-treated cultures compared with the control culture. 1.0 mg Cr(VI) l^?1 reduced the photosynthetic pigments content and altered the cellular morphology, the gain in dry weight was not affected. At steady state, Cr(VI) removal efficiency was 43.5 ± 1.0% and Cr(VI) uptake was 1.7 ± 0.1 mg Cr(VI) g^?1 DB. The system reached a specific metal removal rate of 458 μg Cr(VI) g^?1 DB d^?1, and a volumetric removal rate of 132 μg Cr(VI) l^?1 d^?1.     

Effects of zinc deficiency and zinc supplementation on homocysteine levels and related enzyme expression in rats

Methionine synthase (MS) and betaine-homocysteine methyltransferase (BHMT) are both zinc (Zn)-dependent methyltransferases and involved in the methylation of homocysteine. The objective of this study was to investigate the effects of dietary Zn supply on homocysteine levels and expression of the two enzymes in growing rats. Male weanling Sprague-Dawley rats were assigned randomly to four dietary groups (n = 8/group) for 3 weeks: Zn deficient (ZD; <1 mg Zn/kg); Zn control (ZC; 30 mg Zn/kg); Zn supplemented (ZS; 300 mg Zn/kg); pair fed (PF; 30 mg Zn/kg) to the ZD group. Serum and femur Zn concentrations were 83% and 58% lower in ZD, and 49% and 62% higher in ZS compared to ZC (P < 0.001), respectively. The ZD rats had lower feed intake (37%), body weight gains (45%), liver (43%) and kidney (31%) weights than those of ZC (P < 0.001), but these parameters in ZD were not significantly different from the PF controls. Serum homocysteine concentrations were 65% higher in ZD compared to PF (P < 0.05), and there was no significant difference in serum folate levels between ZD and PF groups. The mRNA expression of liver and kidney MS was 57% and 38% lower in ZD than PF (P < 0.001), respectively. Hepatic and renal BHMT mRNA levels were not altered in ZD compared to controls. The aforementioned measurements were not significantly different between ZS and ZC groups, except Zn levels. These results demonstrated that homocysteine homeostasis appeared to be disturbed by Zn deficiency but not Zn supplementation, and elevated serum homocysteine might be due to reduced expression of MS during Zn deficiency.     

Embryo production and progesterone profiles in ewes superovulated with different hormonal treatments

The superovulatory response and embryo yield following hormonal treatments of Merino ewes during late spring and their estrous cycle were evaluated. Ewes (n=17) were treated with progestagen-impregnated sponges and assigned to Group I (800 IU PMSG plus 11.5 mg FSH-p); Group II (1200 IU PMSG); Group III (1600 IU PMSG). Ewes were naturally mated and followed by laparotomy 6 days later. After laparotomy, ewes were injected with a prostaglandin analogue (PGF) and serum samples were obtained prior to surgery and then for 25 days to measure progesterone (P4) by radioimmunoassay. There were no differences among groups neither for estrous incidence (Group I: 83.3%; Group II: 83.3%; Group III: 100%), nor for the time interval to estrous onset (Group I: 26.4±2.4 h; Group II: 28.8±2.9 h; Group III: 24.0±3.8 h). Group I had more corpora lutea than Group II (14.2±1.2 and 6.2±0.8; P<0.05), and Group III was intermediate (11.0±3.0). There was a low incidence of persistent follicles in all treatments (Group I: 0.5±0.5; Group II: 0.6±0.4; Group III: 1.8±1.2). Number of collected ova were 9.0±2.6, 3.8±0.6 and 6.5±0.9 for Groups I, II and III, respectively. Significant differences in number of ova were detected between Groups I and II. Unfertilized ova did not differ among groups (Group I: 3.5±1.0; Group II: 2.8±0.8; Group III: 5.2±1.4; P>0.05). Embryos and high viability embryos were higher (P<0.05) in Group I (5.2±1.9 and 4.8±2.0) than in Group II (1.0±0.5 and 1.0±0.5) or Group III (1.2±0.6 and 1.0±0.5). Total plasma progesterone (P4) and P4 per corpus luteum before PGF administration did not vary (P>0.05) among groups (Group I: 71.0±14.7 and 4.9±0.7 nmol/l; Group II: 50.6±13.3 and 7.9±1.6 nmol/l; Group III: 90.4±42.6 and 6.8±1.8 nmol/l). There was a significant and positive correlation between P4 before PGF administration and number of corpora lutea (r=0.76). No significant differences were detected among groups for: interval PGF to P4 <3.18 nmol/l (Group I: 2.7±0.3 days; Group II: 1.8±0.6 days; Group III: 2.2±0.5 days), cycle length (Group I: 18.3±1.4 days; Group II: 17.9±0.5 days; Group III: 16.8±0.9 days), duration of P4 levels <3.18 nmol/l (Group I: 11.3±1.9 days; Group II: 7.1±1.0 days; Group III: 7.2±2.4 days), duration of P4 levels ≥3.18 nmol/l (Group I: 7.0±1.3 days; Group II: 10.8±0.8 days; Group III: 9.5±1.7 days) and peak of P4 (Group I: 7.4±0.4 nmol/l; Group II: 10.8±1.6 nmol/l; Group III: 9.2±1.9 nmol/l). It was concluded that PMSG–FSH-p treatment was more efficient than PMSG alone for superovulation and embryo production in ewes while P4 profiles were similar among groups.     

Green synthesis of a novel biodegradable copolymer base on cellulose and poly(p-dioxanone) in ionic liquid

A new cellulose graft copolymer was synthesized in 1-N-butyl-3-methylimidazolium chloride ([Bmim]Cl) by the ring opening graft polymerization (ROGP) of p-dioxanone (PDO) onto cellulose. The structure of the copolymer was characterized by ¹³C and ¹H NMR, WAXD, DSC as well as SEM. Cellulose graft copolymers with a molar substitution (MS) in the range of 2.08–4.60 were obtained with 24 h at 80 °C in a completely homogeneous procedure. The obtained copolymers exhibited the clear glass transition temperatures (T_g) indicating the inter-molecular and intra-molecular hydrogen bonds in cellulose molecules had been destroyed. The reaction media applied can be easily recycled and reused.     

Home environment and cord blood levels of lead,arsenic, and zinc on neurodevelopment of 24 months children living in Chitwan Valley,Nepal

In a birth cohort living in Chitwan Valley, lowland Nepal, we have previously reported inverse associations between in utero levels of lead (Pb), arsenic (As) and neurodevelopment at birth measured by the Brazelton Neonatal Behavioral Assessment Scale, third edition (NBAS III). In the present paper, a follow-up of the same cohort was made on 24-month-old infants regarding the neurodevelopmental effects of these metals, taking the postnatal environment into account. In total, the same100 mother-infant pairs as the previous study, whose Pb, As, and Zn concentrations in cord blood were known, were recruited. Postnatal raising environment was evaluated using the Home Observation for Measurement of Environment (HOME) scale. Neurodevelopment of children at 24 months of age (n = 74) was assessed using the Bayley Scale of Infant Development, Second Edition (BSID II). Multivariable regression adjusting for covariates was performed to determine the associations of in utero levels of toxic and essential elements and the home environment with neurodevelopment scores. Unlike the NBAS III conducted for newborns, none of the BSID II cluster scores in 24-month-old infants were associated with cord blood levels of Pb, As, and Zn. The total HOME score was positively associated with the mental development scale (MDI) score (coefficient = 0.67, at 95% CI = 0.03 to 1.31). In this cohort, a detrimental effect of in utero Pb and As on neurodevelopmental indicators observed at birth disappeared at 24 months, while an association between neurodevelopment and home environment continued.     

Graft polymers of eucalyptus lignosulfonate calcium with acrylic acid: Synthesis and characterization

The graft copolymerization of eucalyptus lignosulfonate calcium (HLS-Ca) from hardwood and acrylic acid (AA) was investigated by using Fenton agent as a coinitiator. The influences of reaction conditions on grafting parameters i.e. product yield (Y%), AA conversion (C%), grafting ratio (G%) and grafting efficiency (GE%) were carefully studied. The effects of the phenolic hydroxyl (Ph-OH) group on the polymerization of AA and grafting reaction were researched. Graft copolymers were identified by the new absorption at 1727 cm^?1, more homogenized morphology and higher decomposition temperature after grafted with AA, as illustrated in FTIR, SEM and TG spectra. The optimum synthesis conditions are as follows: H₂O₂ = 25.2 mol/L, FeCl₂ = 63.0 mol/L, T = 50 °C and t = 2 h and the optimum percentages of Y, C, G and GE are 97.61%, 95.23%, 71.29% and 78.85%, respectively. The Ph-OH group of HLS-Ca cannot inhibit the polymerization of AA and is involved in the grafting reaction as an active center.