Influence of glutamic acid enantiomers on C-mineralization.

Seasonal dynamics in the mineralization of glutamic acid enantiomers in soils from selected ecosystems was determined and subjected to a range of treatments: ambient x elevated CO2 level and meadow x dense x thinned forest environment. Mineralization of glutamic acid was determined by incubation of the soil with 2 mg L- or D-glutamic acid g(-1) of dry soil to induce the maximum respiration rate. Mineralization of glutamic acid enantiomers in soils fluctuates over the course of a vegetation season, following a similar trend across a range of ecosystems. Mineralization is affected by environmental changes and management practices, including elevated CO2 level and thinning intensity. L-glutamic acid metabolism is more dependent on soil type as compared to metabolism of its D-enantiomer. The results support the hypothesis that the slower rate of D- compared to L- amino acid mineralization is due to different roles in anabolism and catabolism of the soil microbial community.

Effect of elevated CO2, O3, and UV radiation on soils.

In this work, we have attempted to review the current knowledge on the impact of elevated CO2, O3, and UV on soils. Elevated CO2 increases labile and stabile soil C pool as well as efficiency of organic pollutants rhizoremediation and phytoextraction of heavy metals. Conversely, both elevated O3 and UV radiation decrease inputs of assimilates to the rhizosphere being accompanied by inhibitory effects on decomposition processes, rhizoremediation, and heavy metals phytoextraction efficiency. Contrary to elevated CO2, O3, or UV-B decreases soil microbial biomass, metabolisable C, and soil N t content leading to higher C/N of soil organic matter. Elevated UV-B radiation shifts soil microbial community and decreases populations of soil meso- and macrofauna via direct effect rather than by induced changes of litter quality and root exudation as in case of elevated CO2 or O3. CO2 enrichment or increased UV-B is hypothesised to stimulate or inhibit both plant and microbial competitiveness for soluble soil N, respectively, whereas O3 favours only microbial competitive efficiency. Understanding the consequences of elevated CO2, O3, and UV radiation for soils, especially those related to fertility, phytotoxins inputs, elements cycling, plant-microbe interactions, and decontamination of polluted sites, presents a knowledge gap for future research.

Natural occurrence of enantiomers of organic compounds versus phytoremediations: should research on phytoremediations be revisited? A mini-review.

Decontamination of polluted soils using plants is based on the ability of plant species (including transgenic plants) to enhance bioavailability of pollutants in the rhizosphere and support growth of pollutant-degrading microorganisms via root exudation and plant species-specific composition of the exudates. In this work, we review current knowledge of enantiomers of low-molecular-weight (LMW) organic compounds with emphasis on their use in phytoremediation. Many research studies have been performed to search for plants suitable for decontamination of polluted soils. Nevertheless, the natural occurrence of L- versus D-enantiomers of dominant compounds of plant root exudates which play different roles in the complexation of heavy metals, chemoattraction, and support of pollutant-degrading microorganisms were not included in these studies. D-enantiomers of aliphatic organic acids and amino acids or L-enantiomers of carbohydrates occur in high concentrations in root exudates of some plant species, especially under stress, and are less stimulatory for plants to extract heavy metals or for rhizosphere microflora to degrade pollutants compared with L-enantiomers (organic acids and amino acids) or D-carbohydrates. Determining the ratio of L- versus D-enantiomers of organic compounds as a criterion of plant suitability for decontamination of polluted soils and development of other types of bioremediation technologies need to be subjects of future research.

Aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil: a review.

Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic) and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research.

Significance of the natural occurrence of L- versus D-pipecolic acid: a review.

Pipecolic acid naturally occurs in microorganisms, plants, and animals, where it plays many roles, including the interactions between these organisms, and is a key constituent of many natural and synthetic bioactive molecules. This article provides a review of current knowledge on the natural occurrence of pipecolic acid and the known and potential significance of its L- and D-enantiomers in different scientific disciplines. Knowledge gaps with perspectives for future research identified within this article include the roles of the L- versus the D-enantiomer of pipecolic acid in plant resistance, nutrient acquisition, and decontamination of polluted soils, as well as rhizosphere ecology and medical issues.

Correlation of lipoprotein (a) concentration with the extent of coronary artery disease in patients on lipid lowering therapy.

OBJECTIVES: Lipoprotein (a) [Lp(a)], together with other serum lipoproteins have an important role in the pathogenesis of coronary heart disease. The objective of the study was to assess the association between plasma levels of Lp(a) with the extent of angiographically defined coronary artery disease (CAD). PATIENTS AND METHODS: A total of 518 consecutive patients (66 % males) underwent coronary angiography in connection with lipids and lipoprotein determinations between 1st January and 31st May 2010. Most of the patients were treated with lipid lowering therapy (77 % statins). Modified angiographic Gensini Score (GS) and adjusted angiographic score (AS) were used to reflect the extent of coronary atherosclerosis. RESULTS: Both GS and AS angiographic scores correlated significantly with age, male gender, statin therapy and inversely with left ventricular ejection fraction (p<0.05-0.01 for all). The results showed significant inverse correlation of HDL cholesterol levels with GS and AS (r=-0.16, p<0.001), and apolipoprotein A levels with GS and AS (r=-0.20, p<0.0001) and a positive correlation of Lp(a) levels with angiographic score (r=0.13, p<0.01) and with adjusted angiographic score (r=0.16, p<0.01). Regression analysis showed only Lp(a) concentration was an independent lipid factor that correlated with the extent of CAD. CONCLUSION: Only Lp(a) levels correlated with the extent of coronary artery disease as assessed with coronary angiography in patients treated with lipid lowering therapy.

Determination of the proportion of total soil extracellular acid phosphomonoesterase (E.C. 3.1.3.2) activity represented by roots in the soil of different forest ecosystems.

The aim of this study is to present a new method for determining the root-derived extracellular acid phosphomonoesterase (EAPM) activity fraction within the total EAPM activity of soil. EAPM activity was determined for roots, organic and mineral soil. Samples were collected using paired PVC cylinders, inserted to a depth of 15 cm, within seven selected forest stands. Root-derived EAPM formed between 4 and18% of the total EAPM activity of soil from forests of differing maturity. A new approach, presented in this work, enables separation of root-derived EAPM activity from total soil EAPM. Separation of root-derived EAPM from soil provides a better understanding of its role in P-cycling in terrestrial ecosystems. The method presented in this work is a first step towards the separation of root- and microbe-derived EAPM in soils, which are thought to possess different kinetic properties and different sensitivity to environmental change.

Contribution of Miscanthus x giganteus root exudates to the biostimulation of PAH degradation: an in vitro study.

Phytoremediation is considered as a promising and cost-effective method to enhance bioremediation of polluted soils. Exudation of plant root secondary metabolites similar to organic pollutants may induce the expression of microbial degradative enzymes and favour cometabolism of xenobiotics. We investigated the contribution of Miscanthus x giganteus root exudates in the biostimulation of PAH-degradation. This perennial grass was chosen because of its capability to grow on polluted soils and its high biomass production for non-food purposes. First, the impact of cometabolism phenomena was evaluated on the selective enrichment of pyrene-degrading bacterial consortia. The identification of each isolated strains following incubation with pyrene only, "pyrene+phenanthrene", "pyrene+salycilate" or "pyrene+diesel fuel" showed a varying bacterial diversity and pyrene-degrading ability, depending on the co-substrate used. Then, a microplate assay was designed, based on the simultaneous measurement of bacterial consortia growth and degradation activity, in the presence of PAH and total root exudates. Results showed that i) the addition of root exudates was efficient for promoting bacterial growth, ii) but a selective enrichment of PAH-degraders compared to aliphatic ones could be clearly demonstrated, thereby conducing to an enhanced PAH catabolism. The identification of plant secondary metabolites showed the presence of a broad range of flavonoid-derived compounds that could play a role in cometabolic processes. Microplate assays with the two major molecules, quercetin and rutin, suggested a partial involvement of these compounds in biostimulation processes. Further investigations with the other identified secondary metabolites (apigenin, isovitexin, catechin, gallic and caffeic acid) should provide more information on the exudate-PAH cometabolic degradation phenomenon.

Use of intracardiac echocardiography to guide implantation of a left atrial appendage occlusion device (PLAATO).

BACKGROUND: Over 90% of thrombi in atrial fibrillation (AF) originate from the left atrial appendage (LAA). Patients with contraindications to anticoagulation are potential candidates for LAA occlusion using the Percutaneous Left Atrial Appendage Transcatheter Occlusion system (PLAATO, ev3 Inc., Plymouth, MN). Transesophageal echocardiography (TEE) is typically used to guide implantation. OBJECTIVE: This study sought to examine the utility of intracardiac echocardiography (ICE) in providing adequate imaging guidance as an alternative to TEE during PLAATO implantation. METHODS: The study group consisted of 10 patients who underwent PLAATO implantation with simultaneous TEE and ICE imaging guidance. ICE was used to perform the following tasks typically fulfilled by TEE: (1) verification of the absence of LAA thrombus, (2) identification of the LAA ostial dimension for device sizing, (3) guidance of transseptal puncture, (4) verification of the delivery sheath position, and (5) confirmation of location and stability of device before its irrecoverable release. The ability of ICE to perform these tasks was assessed from three separate positions: the standard right atrial (RA) position, within the coronary sinus (CS), and the right ventricular outflow tract. RESULTS: ICE imaging of the LAA was optimal from within the CS, although imaging from the proximal pulmonary artery provided better visualization of the distal LAA in cross-section. The LAA dimensions, confirmation of the absence of LAA thrombus, proper positioning of the delivery sheath, verification of location and stability of the device obtained by ICE were consistent with findings from TEE. CONCLUSION: Using nonconventional imaging planes, ICE imaging was able to perform the intraprocedural functions provided by TEE during implantation of the PLAATO left atrial appendage occlusion device.

Supercritical fluid extraction of bioavailable amino acids from soils and their liquid chromatographic determination with fluorometric detection.

A new procedure with supercritical CO2 modified with 0.5 mL of water and 0.75 mL of 0.1 M HCl in situ and 0.75 mL of water on-line at 15 MPa and 50 degrees C for 45 min was applied for the extraction of bioavailable amino acids from soil samples. Total extraction time was 60 min, but more favorable conditions are even possible for selected groups of amino acids. All analytes were trapped into 20 mL of methanol with satisfactory recovery (94-104%) and determined using high-performance liquid chromatography with fluorometric detection on a Zorbax Eclipse column (4.6 x 75 mm, 3.5 microm) with Na2HPO4 and acetonitrile/methanol/water as a mobile phase. Linear calibration curves were obtained (r > 0.999 except 0.99823 for Ile) with lower limits of detection (S/N = 3) in the range from 1.54 pg (Gly) to 13.5 pg (Cy2) or from 18.6 fmol (Ser) to 64.8 fmol (Lys). Validation and repeatability data are also given. Comparable results were obtained with a robust, commonly used extraction method (0.5 M ammonium acetate, 60 min in shaker, followed by filtration and lyophilization). Limiting values of artificial release of amino acids were also determined for each soil sample to eliminate any false results to ensure that all extracted amino acids originate from soil solution and exchangeable bound positions of soil samples.

Three-dimensional morphology of the palate in subjects with unilateral complete cleft lip and palate at the stage of permanent dentition.

OBJECTIVE: Three-dimensional analysis of palate size and shape in patients with complete unilateral cleft lip and palate (UCLP) at the stage of permanent dentition. SUBJECTS: Thirty randomly selected dental casts of boys approximately 15 years old with complete UCLP and 28 dental casts of normal boys of the same age. INTERVENTIONS: All patients underwent lip repair according to Tennison with primary periosteoplasty (mean age 8.5 months) and palate repair by pushback and pharyngeal flap surgery (mean age 4.9 years). MAIN OUTCOME MEASURES: Data on the palate height in 210 defined locations. RESULTS: The palate in patients with UCLP was narrower throughout its whole extent, more anteriorly than posteriorly. From the canines posteriorly, it was also lower, and the difference as compared with controls increased in a posterior direction up to the level of second premolars (up to 30%) and then slightly diminished (to 21% between the first molars). The reduction of area of transverse sections reached 45% between premolars and 39% between first molars. The palate in the anterior portion was highest on the cleft side and in a posterior direction the maximum height of the palate shifted toward the midline and even beyond that line toward the noncleft side. Palatal height did not depend on dentoalveolar arch width. CONCLUSION: The smaller width and height of the palate confirm the substantially reduced space for the tongue in patients with UCLP. The reduction is only slightly larger than in previously examined patients with isolated cleft palate. Palatal vault is asymmetrical, highest anteriorly on the cleft side and posteriorly on the noncleft side.

Assessing the use of delta(13)C natural abundance in separation of root and microbial respiration in a Danish beech (Fagus sylvatica L.) forest.

Our understanding of forest biosphere-atmosphere interactions is fundamental for predicting forest ecosystem responses to climatic changes. Currently, however, our knowledge is incomplete partly due to inability to separate the major components of soil CO(2) effluxes, viz. root respiration, microbial decomposition of soil organic matter and microbial decomposition of litter material. In this study we examined whether the delta(13)C characteristics of solid organic matter and respired CO(2) from different soil-C components and root respiration in a Danish beech forest were useful to provide information on the root respiration contribution to total CO(2) effluxes. The delta(13)C isotopic analyses of CO(2) were performed using a FinniganMAT Delta(PLUS) isotope-ratio mass spectrometer coupled in continuous flow mode to a trace gas preparation-concentration unit (PreCon). Gas samples in 2-mL crimp seal vials were analysed in a fully automatic mode with an experimental standard error +/-0.11 per thousand. We observed that the CO(2) derived from root-free mineral soil horizons (A, B(W)) was more enriched in (13)C (delta(13)C range -21.6 to -21.2 per thousand ) compared with CO(2) derived from root-free humus layers (delta(13)C range -23.6 to -23.4 per thousand ). The CO(2) evolved from root respiration in isolated young beech plants revealed a value intermediate between those for the soil humus and mineral horizons, delta(13)C(root) = -22.2 per thousand, but was associated with great variability (SE +/- 1.0 per thousand ) due to plant-specific differences. delta(13)C of CO(2) from in situ below-ground respiration averaged -22.8 per thousand, intermediate between the values for the humus layer and root respiration, but variability was great (SE +/- 0.4 per thousand ) due to pronounced spatial patterns. Overall, we were unable to statistically separate the CO(2) of root respiration vs. soil organic matter decomposition based solely on delta(13)C signatures, yet the trend in the data suggests that root respiration contributed approximately 43% to total respiration. The vertical gradient in delta(13)C, however, might be a useful tool in partitioning respiration in different soil layers. The experiment also showed an unexpected (13)C-enrichment of CO(2) (>3.5 per thousand ) compared with the total-C signatures in the individual soil-C components. This may suggest that analyses of bulk samples are not representative for the C-pools actively undergoing decomposition.

Three-dimensional analysis of maxillary dental casts using Fourier transform profilometry: precision and reliability of the measurement.

OBJECTIVE: Fourier transform profilometry was used for the three-dimensional measurement of maxillary dental casts to analyze the size and shape of the palate. The objective of this study was to test the accuracy of the measuring system and determine the precision and reliability of the measurement METHODS: Images of dental casts were analyzed using newly developed measuring software. Based on five landmarks located on the alveolar ridge, the measuring software constructed 10 transversal sections of the palate. In each section profile, the width, area, and 23 height variables were assessed. SUBJECTS: Maxillary dental stone casts of 25 healthy girls, 14.1 to 15.3 years of age, were studied. RESULTS: The technical error of measurement exceeded 5% of the size of the measurement only in variables with means less than approximately 3 mm. In fact, such small absolute dimensions were exhibited only by the palate height in anterior profile 2 and the palate height at the margins of other profiles. Reliability of the measurements was found to be very high for the width and area of the profiles. For height measurements, the coefficient of reliability was slightly lower at the profile margins than near the midline. Nevertheless, only three height variables showed a coefficient of reliability lower than 0.90. The coefficients of reliability of other height measurements of profiles 3 through 10 were only sporadically lower than 0.97. CONCLUSION: With regard to the accuracy of the measuring system as well as the precision and reliability of the measurement, this method proved to be a suitable tool for studying palatal morphology.

Three-dimensional morphology of the palate in subjects with isolated cleft palate at the stage of permanent dentition.

OBJECTIVE: Three-dimensional analysis of palate size and shape in patients with isolated cleft palate at the stage of permanent dentition. DESIGN: Cross-sectional study using Fourier transform profilometry. SUBJECTS: Twenty-nine randomly selected dental casts of approximately 15-year-old boys with isolated cleft palate and 28 dental casts of normal boys of the same age. INTERVENTIONS: All patients were operated on by the same method (pushback and pharyngeal flap surgery) at a mean age of 4.5 years. MAIN OUTCOME MEASURES: Data on the palate height in 210 defined locations (pixels). RESULTS: The palate in isolated clefts is narrower throughout its whole extent and lower from the level of the first premolars. The difference, as compared with controls, increases in a posterior direction. At the level of the first molars, palatal height is reduced by one-quarter, the area of the transversal section by more than one-third. The shaping of the palate vault is, on average, symmetrical with a marked interindividual variability. Palatal height does not depend on the width of the dentoalveolar arch, and the height of the primary palate is not reduced. CONCLUSION: The smaller width and reduced height from the level of the first premolars posteriorly confirm the substantially reduced space available for the tongue in patients with isolated cleft palate. Deviations are on the average symmetrical, and the anterior part of the palate is not shallower.