Differential Complexation between Zn2+ and Cd2+ with Fulvic Acid: A Computational Chemistry Study

Fulvic (FA) and humic acids (HA) from the solubilization of organic matter are significant agents of the complex of metallic ions in soil and water. Cadmium ions are important natural water pollutants which are discharged along with electroplating and zinc metallurgy liquid wastes, zinc and cadmium being always associated with isomorphic substitution. In this paper we study the complexes formed by Zn²⁺ and Cd²⁺ with fulvic acids, using computational chemistry. We carried out relative free energy calculations using a thermodynamic cycle and Free Energy Pertubation (FEP) and Density Functional Theory (DFT-B3LYP/6-31G**) methods. We also computed the interaction energies between orbitals from Natural Bond Order (NBO) calculations. Cd-FA complexes, octahedral with four water molecules in the coordination sphere are more stable than Zn-FA complexes, tetrahedral with two water molecules. This means that FA should be a better ligand for Cd²⁺ bioavailability and toxicity in natural aquatic environments.     

Real-time quantitative PCR detection of genetically modified Maximizer maize and Roundup Ready soybean in some representative foods

A fast and quantitative method was developed to detect transgenic "Maximizer" maize "event 176" (Novartis) and "Roundup Ready" soybean (Monsanto) in food by real-time quantitative PCR. The use of the ABI Prism 7700 sequence detection system allowed the determination of the amplified product accumulation through a fluorogenic probe (TaqMan). Fluorescent dyes were chosen in such a way as to coamplify total and transgenic DNA in the same tube. Using real-time quantitative PCR, 2 pg of transgenic or total DNA per gram of starting sample was detected in 3 h after DNA extraction and the relative amounts of "Maximizer" maize and "Roundup Ready" soybean in some representative food products were quantified.     

Retention of Staphylococci and Total Coliforms During Wastewater Percolation Through Equatorial Soil in Central Africa: The Role of the Soil Column Near Soil Surface and that Closely Above Groundwater Table

Groundwater protection from pollutants depends mostly on retention potentials of soil above groundwater table. Soil separating soil surface from groundwater table is made up of several layers and can be divided into different columns along its vertical transect. Wastewater percolation tests were carried out through one soil column CA, in contact with soil surface and through another CB, closely above groundwater table. The aim of the study was to assess the importance of soil columns CA and CB, in total coliforms and staphylococci retention during wastewater infiltration or groundwater recharge, in equatorial soils in Central African region. The results showed that, the fraction of total coliforms retained through soil column CA varied with respect to wastewater loads applied on top of soil column, from 69.22% to 99.95%, relative to the total coliforms concentration deposited on top. The fraction of total coliforms retained through CB varied with respect to wastewater loads applied, from 96.98 to 99.89% relative to the total coliforms deposited on top. Through both soil columns, fractions of staphylococci retained was in the order of 99.99% relative to the total staphylococci concentration deposited on top. For the whole bacteriological analysis, the fractions of total coliforms retained seems to be greater through deeper soil column than that of upper soil column. The bacterial contaminants retained relative to their concentrations in wastewater poured on soil column surfaces, varied from 6.17 log units to 9.73 log units. An applied load of 100 ml seemed to lead to the bacterial pollutants transported through both soil columns studied. NH₄ ⁺ was retained by fractions varying from 97.37 to 98.74%. Concentrations of various contaminants found in groundwater would be a tiny part, relative to quantities deposited on soil surface. Bacterial retention potentials of soil column separating soil surface from groundwater table during wastewater percolation, varies along its transect. It would be due to numerous and variable physical, chemical and structural properties of soil layers and bacteria on the one hand, and to results of various interactions between soil layer particles and cell bacteria, on the other hand.     

Climatic adaptation of trees: rediscovering provenance tests

Summary Common garden testing of populations of different origin started with forest trees more than two hundred years ago. Since then, so-called provenance tests have been established with most commercially important species. Beyond the strictly silvicultural goals, the tests offer excellent opportunities to study intraspecific genetic variation patterns and represent probably the most powerful available tool for testing hypotheses of climatic adaptation in trees.Analysis of adaptive traits (mostly juvenile height growth) in provenance experiments indicate the existence of very effective constraints on adaptedness. The performance of populations plotted against an ecological-climatic factor exhibits a characteristic pattern and can be described by response functions. The population average of a fitness-related trait for a locally adapted population is often significantly lower than that of populations from other environments; usually the ones from milder climate perform better. The phenomenon is interpreted as adaptation lag. Suboptimal adaptation is compensated by a high level of genetic diversity. Molecular genetic studies confirm the high level of allelic and individual genetic diversity in forest trees. A consequence of individual homeostasis, phenotypic stability of populations is usually also high; the sensitivity to environmental changes is generally moderate. Phenotypically stable populations are valuable not only because of a wider range of potential cultivation but specifically because of a greater ability to adjust to unexpected changes. This trait should receive more attention in the future for obvious reasons.The maintenance of a high within-population genetic variance is favored by the genetic system of the investigated species (effective gene flow, outbreeding, high genetic load, etc.). Random events and long-lasting biotic interactions are further effects impairing the efficiency of natural selection.In view of expected climate instability, genetic adaptability of forest trees causes serious concern due to their long lifespan compared to the rapidity of expected changes in environmental conditions. The potential of provenance tests to interpret long-term adaptational processes should be utilized to analyze, model and predict response of trees to climate change. Although seldomly appreciated, provenance research might be among the most important contributions of forestry to biological sciences.     

Present and forecasted xeric climatic limits of beech and sessile oak distribution at low altitudes in Central Europe

• Introduction   

Xeric (trailing) forest range limits are particularly vulnerable to impacts of predicted climate change. Regional modelling studies contribute to the identification of potential local climatic threats and may support appropriate management strategies.     

Ionic interactions and salinity affect monoterpene and phenolic diterpene composition in rosemary (Rosmarinus officinalis)

In this study, we evaluated how increased cation supply can alleviate the toxic effects of NaCl on plants and how it affects essential oils (EOs) and phenolic diterpene composition in leaves of rosemary (Rosmarinus officinalis L.) plants grown in pots. Two concentrations of the chloride salts KCl, CaCl₂, MgCl₂, and FeCl₃ were used together with 100 mM NaCl to study the effects of these nutrients on plant mineral nutrition and leaf monoterpene, phenolic diterpene, and EO composition. The addition of 100 mM NaCl, which decreased K⁺, Ca²⁺, and Mg²⁺ concentrations with increasing Na⁺ in leaves, significantly altered secondary metabolite accumulation. Addition of MgCl₂ and FeCl₃ altered leaf EO composition in 100 mM NaCl–treated rosemary plants while KCl and CaCl₂ did not. Furthermore, addition of CaCl₂ promoted the accumulation of the major phenolic diterpene, carnosic acid, in the leaves. The carnosol concentration was reduced by the addition of KCl to salt‐stressed plants. It is concluded that different salt applications in combination with NaCl treatment may have a pronounced effect on phenolic diterpene and EO composition in rosemary leaves thus indicating that ionic interactions may be carefully considered in the cultivation of these species to achieve the desired concentrations of these secondary metabolites.     

Effects of processing steps on the phenolic content and antioxidant activity of beer

A new analytical method (liquid chromatography-antioxidant, LC-AOx) was used that is intended to separate beer polyphenols and to determine the potential antioxidant activity of these constituents after they were allowed to react online with a buffered solution of the radical cation 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(?+)). Using the LC-AOx method, it was possible to demonstrate that the extent of the antioxidant activity was very much dependent on the phenolic compound considered. The method was also applied to the analysis of beer extracts and allowed the evaluation of their antioxidant activity at different steps of beer processing: brewing, boiling, and fermentation. This study showed that the total antioxidant activity remained unchanged throughout beer processing, as opposed to the polyphenolic content, which showed a 3-fold increase. Hopping and fermentation steps were the main causes of this increase. However, the increase measured after fermentation was attributed to a better extraction of polyphenols due to the presence of ethanol, rather than to a real increase in their content. Moreover, this method allowed the detection of three unknown antioxidant compounds, which accounted for 64 ± 4% of the total antioxidant activity of beer and were individually more efficient than caffeic acid and epicatechin.     

Catabolism of L-ascorbate by Lactobacillus rhamnosus GG

Catabolism of L-ascorbate by enteric bacteria is well documented, but no study has formally proved that bacteria of the Lactobacillus genus ferment this compound. However, some genes analogous to those of yiaK-S operon and ula regulon, which encoded proteins leading to L-ascorbate degradation by Escherichia coli and Klebsiella pneumoniae , have been identified in the recently sequenced Lactobacillus rhamnosus GG genome. Investigations by HPLC and in vivo (13)C NMR using L-[1,6-(13)C]-ascorbate showed that L. rhamnosus GG, a common probiotic strain, has the ability to catabolize L-ascorbate under anaerobiosis. The main products of the ascorbate degradation have been identified as CO(2), acetate, and lactate. These results are in accordance with the metabolic pathway proposed for the fermentation of L-ascorbate by E. coli.     

The Adverse Effect of Phytoestrogens on the Synthesis and Secretion of Ovarian Oxytocin in Cattle

The current investigations were undertaken to study the mechanism of the adverse effect of phytoestrogens on the function of bovine granulosa (follicles >1< cm in diameter) and luteal cells from day 1–5, 6–10, 11–15, 16–19 of the oestrous cycle. The cells were incubated with genistein, daidzein or coumestrol (each at the dose of 1 × 10^?6 m ). The viability and secretion of estradiol (E2), progesterone (P4) and oxytocin (OT) were measured after 72 h of incubation. Moreover, the expression of mRNA for neurophysin‐I/OT (NP‐I/OT; precursor of OT) and peptidyl‐glycine‐α‐amidating monooxygenase (PGA, an enzyme responsible for post‐translational OT synthesis) was determined after 8 h of treatment. None of the phytoestrogens used affected the viability of cells except for coumestrol. The increased secretion of E2 and P4 was only obtained by coumestrol (p < 0.05) from granulosa cells from follicles <1 cm in diameter and decreased from luteal cells on days 11–15 of the oestrous cycle, respectively. All three phytoestrogens stimulated (p < 0.05) OT secretion from granulosa and luteal cells in all stages of the oestrous cycle and the expression of NP‐I/OT mRNA in the both types of cells. The expression of mRNA for PGA was stimulated (p < 0.05) by daidzein and coumestrol in granulosa cells, and by genistein and coumestrol in luteal cells. In conclusion, our results demonstrate that these phytoestrogens can impair the ovary function in cattle by adversely affecting the synthesis of OT in follicles and in corpus luteum. However, their influence on the ovarian steroids secretion was less evident.