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Biogenic volatile organic compounds (BVOCs) emissions from Abies alba in a French forest.

Air quality studies need to be based on accurate and reliable data, particularly in the field of the emissions. Biogenic emissions from forests, crops, and grasslands are now considered as major compounds in photochemical processes. Unfortunately, depending on the type of vegetation, these emissions are not so often reliably defined. As an example, although the silver fir (Abies alba) is a very widespread conifer tree in the French and European areas, its standard emission rate is not available in the literature. This study investigates the isoprene and monoterpenes emission from A. alba in France measured during the fieldwork organised in the Fossé Rhénan, from May to June 2003. A dynamic cuvette method was used. Limonene was the predominant monoterpene emitted, followed by camphene, alpha-pinene and eucalyptol. No isoprene emission was detected. The four monoterpenes measured showed different behaviours according to micrometeorological conditions. In fact, emissions of limonene, alpha-pinene and camphene were temperature-dependant while eucalyptol emissions were temperature and light dependant. Biogenic volatile organic compounds emissions were modeled using information gathered during the field study. Emissions of the three monoterpenes previously quoted were achieved using the monoterpenes algorithm developed by Tingey et al. (1980) [Tingey D, Manning M, Grothaus L, Burns W. Influence of light and temperature on monoterpene emission rates from slash pine. Plant Physiol 1980;65: 797-801.] and the isoprene algorithm [Guenther, A., Monson, R., Fall, R., 1991. Isoprene and monoterpene emission rate variability: observations with eucalyptus and emission rate algorithm development. J Geophys Res 26A: 10799-10808.]; [Guenther, A., Zimmerman, P., Harley, P., Monson, R., Fall, R., 1993. Isoprene and monoterpene emission rate variability: model evaluation and sensitivity analysis. J Geophys Res 98D: 12609-12617.]) was used for the eucalyptol emission. With these methods, simulation results and observations agreed fairly well. The standard emission rate (303 K) and beta-coefficient averaged for limonene, camphene and alpha-pinene were respectively of 0.63 microg gdw-1 h-1 and 0.06 K-1. For eucalyptol, the standard emission rate (T=303 K and PAR=1000 micromol m-2 s-1) was 0.26 microg gdw-1 h-1. This classified A. alba as a weak monoterpenes emitter.

Abies↗

Genetic diversity and biogeography of Cunninghamia konishii (Cupressaceae), an island species in Taiwan: a comparison with Cunninghamia lanceolata, a mainland species in China.

Luanta-fir (Cunninghamia konishii), an endemic to Taiwan, is an outcrossing, long-lived conifer. Populations of C. konishii are generally fragmented due to a once high intensity of timber exploitation. C. konishii and Cunninghamia lanceolata are two sibling taxa constituting derivative-progenitor species relationship. The amount of genetic variations within and between 11 and 10 populations of C. konishii and C. lanceolata, respectively, were assessed using amplified fragment length polymorphism (AFLP) markers in this report. Three AFLP primer pairs generated a total of 357 and 226 markers for C. konishii and C. lanceolata samples, of which 56.1 and 65.3% are polymorphic, respectively. Analysis of molecular variance indicates a 4.78% variation between C. konishii and C. lanceolata. A relatively high value of genetic variation (24.60%) was apportioned between the populations of C. konishii. In contrast, a lower divergence value (12.21%) between populations was found for C. lanceolata. The population with the highest genetic diversity was found in Nantou County, which concurred with the results of many other tree species investigated in Taiwan. The estimates of the number of migrants between populations (Nm), obtained from population pair-wise PhiST, suggest that gene flow in C. konishii is efficient in some adjacent populations but is restricted in the rest. Individual UPGMA tree, generated based on AFLP markers, suggests six evolutionary lineages for C. konishii. All evolutionary lineages of C. konishii were derived from C. lanceolata. In conclusion, the migration patterns of Cunninghamia from mainland China may have been established following multiple sources, migrant-pools, long-distance dispersal events, and via different directions.

Genetic Variation↗

Alteration of product formation by directed mutagenesis and truncation of the multiple-product sesquiterpene synthases delta-selinene synthase and gamma-humulene synthase.

Two recombinant sesquiterpene synthases from grand fir, delta-selinene synthase and gamma-humulene synthase, each produce more than 30 sesquiterpene olefins from the acyclic precursor farnesyl diphosphate. These enzymes contain a pair of DDxxD motifs, on opposite lips of the presumptive active site, which are thought to be involved in substrate binding and could promote multiple orientations of the substrate alkyl chain from which multiple families of cyclic olefins could derive. Mutagenesis of the first aspartate of either DDxxD motif resulted in depressed k(cat), with lesser effect on K(m), for delta-selinene synthase and afforded a much simpler product spectrum composed largely of monocyclic olefins. Identical alterations in gamma-humulene synthase produced similar kinetic effects with a simplified product spectrum of mostly acyclic and monocyclic olefins. Although impaired in product diversity, none of the mutant synthases lost entirely the capacity to generate complex structures. These results confirm the catalytic significance of the DDxxD motifs and imply that they also influence permitted modes of cyclization. Deletion of an N-terminal arginine pair in delta-selinene synthase (an element potentially involved in substrate isomerization) altered kinetics without substantially altering product outcome. Finally, mutation of an active-site tyrosine residue thought to play a role in proton exchange had little influence; however, substitution of a nearby active site aspartate dramatically altered kinetics and product outcome.

Alkyl and Aryl Transferases↗

Geranyl diphosphate synthase from Abies grandis: cDNA isolation, functional expression, and characterization.

Geranyl diphosphate synthase catalyzes the condensation of dimethylallyl diphosphate and isopentenyl diphosphate to generate geranyl diphosphate, the essential precursor of monoterpene biosynthesis. Using geranylgeranyl diphosphate synthase from Taxus canadensis as a hybridization probe, four full length cDNA clones, sharing high sequence identity to each other (>69%) and to the Taxus geranylgeranyl diphosphate synthase (>66%), were isolated from a grand fir (Abies grandis) cDNA library. When expressed in Escherichia coli, three of the recombinant enzymes produced geranyl diphosphate and one produced geranylgeranyl diphosphate as the dominant product when supplied with isopentenyl diphosphate and dimethylallyl diphosphate as cosubstrates. One enzyme (AgGPPS2) was confirmed as a specific geranyl diphosphate synthase, in that it accepted only dimethylallyl diphosphate as the allylic cosubstrate and it produced exclusively geranyl diphosphate as product, with a k(cat) of 1.8s(-1). Gel filtration experiments performed on the recombinant geranyl diphosphate synthases, in which the plastidial targeting sequences had been deleted, revealed that these enzymes are homodimers similar to other short-chain prenyltransferases but different from the heterotetrameric geranyl diphosphate synthase of mint.

Abies↗

Hidden Markov modeling for single channel kinetics with filtering and correlated noise.

Hidden Markov modeling (HMM) can be applied to extract single channel kinetics at signal-to-noise ratios that are too low for conventional analysis. There are two general HMM approaches: traditional Baum's reestimation and direct optimization. The optimization approach has the advantage that it optimizes the rate constants directly. This allows setting constraints on the rate constants, fitting multiple data sets across different experimental conditions, and handling nonstationary channels where the starting probability of the channel depends on the unknown kinetics. We present here an extension of this approach that addresses the additional issues of low-pass filtering and correlated noise. The filtering is modeled using a finite impulse response (FIR) filter applied to the underlying signal, and the noise correlation is accounted for using an autoregressive (AR) process. In addition to correlated background noise, the algorithm allows for excess open channel noise that can be white or correlated. To maximize the efficiency of the algorithm, we derive the analytical derivatives of the likelihood function with respect to all unknown model parameters. The search of the likelihood space is performed using a variable metric method. Extension of the algorithm to data containing multiple channels is described. Examples are presented that demonstrate the applicability and effectiveness of the algorithm. Practical issues such as the selection of appropriate noise AR orders are also discussed through examples.

Algorithms↗

250-GHz electron spin resonance studies of polarity gradients along the aliphatic chains in phospholipid membranes.

Rigid-limit 250-GHz electron spin resonance (FIR-ESR) spectra have been studied for a series of phosphatidylcholine spin labels (n-PC, where n = 5, 7, 10, 12, 16) in pure lipid dispersions of dipalmitoylphosphatidylcholine (DPPC) and 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), as well as dispersions of DPPC containing the peptide gramicidin A (GA) in a 1:1 molar ratio. The enhanced g-tensor resolution of 250-GHz ESR for these spin labels permitted a careful study of the nitroxide g-tensor as a function of spin probe location and membrane composition. In particular, as the spin label is displaced from the polar head group, Azz decreases and gxx increases as they assume values typical of a nonpolar environment, appropriate for the hydrophobic alkyl chains in the case of pure lipid dispersions. The field shifts of spectral features due to changes in gxx are an order of magnitude larger than those from changes in Azz. The magnetic tensor parameters measured in the presence of GA were characteristic of a polar environment and showed only a very weak dependence of Azz and gxx on label position. These results demonstrate the significant influence of GA on the local polarity along the lipid molecule, and may reflect increased penetration of water into the alkyl chain region of the lipid in the presence of GA. The spectra from the pure lipid dispersions also exhibit a broad background signal that is most significant for 7-, 10-, and 12-PC, and is more pronounced in DPPC than in POPC. It is attributed to spin probe aggregation yielding spin exchange narrowing. The addition of GA to DPPC essentially suppressed the broad background signal observed in pure DPPC dispersions.

1,2-Dipalmitoylphosphatidylcholine↗

DMPA use above the age of 35 in Thai women.

A prospective study of depot-medroxyprogesterone acetate (DMPA) use in women aged above 35 years was conducted in Bangkok, Thailand. The objectives of the study were to evaluate efficacy, continuation rate, and side effects of DMPA use in these women. A total of 60 women were enrolled in a one-year clinical trial. Their mean age was 38 years. Most of them had completed primary school. No accidental pregnancies occurred throughout the 1-year use in this study. The continuation rate was 20%. Irregular bleeding was the major cause of termination. The major side effect was also irregular bleeding. Nevertheless, DMPA in older women is a safe and effective contraceptive. DMPA is a contraceptive akterbatuve fir women aged above 35 with contraindications to combination oral contraceptives.

Adult↗

Nonlinear eye movement detection method for drowsiness studies.

Automatic long-term vigilance analysis systems require information about the occurrence and type of eye movements, in addition to information about other physiological signals. This paper presents a method to detect different types of eye movements in ambulatory recordings. The method is based on the application of a weighted FIR-median-hybrid filter in the preprocessing of the signal and on the novel use of linear correlation between two EOG signals which are obtained using a new, improved electrode montage. The evaluation of the method showed that it performed well in detecting isolated unambiguous eye movements, but differences were observed in comparison to visual scoring in borderline cases. The method was found to be suitable for use as part of a signal analysis system for drowsiness studies.

Electrooculography↗

Discrete wavelet transform: a tool in smoothing kinematic data.

Motion analysis systems typically introduce noise to the displacement data recorded. Butterworth digital filters have been used to smooth the displacement data in order to obtain smoothed velocities and accelerations. However, this technique does not yield satisfactory results, especially when dealing with complex kinematic motions that occupy the low- and high-frequency bands. The use of the discrete wavelet transform, as an alternative to digital filters, is presented in this paper. The transform passes the original signal through two complementary low- and high-pass FIR filters and decomposes the signal into an approximation function and a detail function. Further decomposition of the signal results in transforming the signal into a hierarchy set of orthogonal approximation and detail functions. A reverse process is employed to perfectly reconstruct the signal (inverse transform) back from its approximation and detail functions. The discrete wavelet transform was applied to the displacement data recorded by Pezzack et al., 1977. The smoothed displacement data were twice differentiated and compared to Pezzack et al.'s acceleration data in order to choose the most appropriate filter coefficients and decomposition level on the basis of maximizing the percentage of retained energy (PRE) and minimizing the root mean square error (RMSE). Daubechies wavelet of the fourth order (Db4) at the second decomposition level showed better results than both the biorthogonal and Coiflet wavelets (PRE = 97.5%, RMSE = 4.7 rad s-2). The Db4 wavelet was then used to compress complex displacement data obtained from a noisy mathematically generated function. Results clearly indicate superiority of this new smoothing approach over traditional filters.

Algorithms↗

Developmental expression and stress induction of glutathione S-transferase in the spruce budworm, Choristoneura fumiferana.

Developmental and stress-induced expression of Choristoneura fumiferana glutathione S-transferase (CfGST) mRNA and protein were examined using Northern blots and Western blots. High levels of CfGST mRNA and protein were detected in 1st instar larvae and diapausing 2nd instar larvae. Expression of CfGST gradually decreased during larval development from 3rd to 5th instar, after which the expression increased once again, reaching peak levels in 6th instar larvae. CfGST mRNA and protein were undetectable in the pupal stage. Exposure to low temperature did not induce an increase in CfGST expression. Feeding on balsam fir foliage resulted in an increase in the expression of CfGST as compared to larvae that fed on artificial diet. The bacterial insecticide, Bacillus thuringiensis delta-endotoxin (Bt), the non-steroidal ecdysone analog, tebufenozide, and the synthetic pyrethroid, permethrin, induced the expression of CfGST mRNA in 5th instar larvae, whereas the chitin synthesis inhibitor, diflubenzuron, did not have any such effect. These results suggest that CfGST plays an important role in detoxifying various allelochemicals and insecticides in the spruce budworm. The developmental expression pattern strongly suggests that in addition to detoxification, CfGST might be involved in other functions.

Journal Article↗

Mercury levels in lichens from different host trees around a chlor-alkali plant in New Brunswick, Canada.

Mercury concentrations were determined in the epiphytic lichen Hypogymnia physodes along five transects starting from a chlor-alkali plant located at Dalhousie, New Brunswick, a landfill site and a nearby electricity generating station. Lichen samples were collected from white birch (Betula papyrifera) and spruce (Picea sp.) or balsam fir (Abies balsamea). Average lichen background mercury values were 0.088+/-0.005 microg/g from white birch and 0.148+/-0.046 microg/g from spruce trees, with a detection limit of 0.05 microg/g. The chlor-alkali plant and a power plant were identified, respectively, as a major source and a minor source of elevated mercury levels in lichens. At 125 m north-west of the New Brunswick Power plant, 0.28 microg/g Hg were found in Hypogymnia physodes from spruce trees, while at 250 m west (downwind) of the chlor-alkali plant, 3.66 microg/g of mercury were determined. High values, 0.98 microg/g in lichens from spruce trees and 0.79 microg/g in lichen samples from white birch were also measured at 125 m south of the chlor-alkali plant and decreased exponentially with distance. The sphere of influence of the chlor-alkali plant with respect to mercury deposition was estimated to extend 2.4-3.4 km from the plant. The mercury concentrations in Hypogymnia physodes collected from white birch were significantly lower than the concentrations in the same lichen from spruce trees in areas with elevated levels of mercury, but not in areas with low mercury levels. The magnitude of this difference dropped with distance from the source.

Air Pollutants↗

Monitoring historical changes in soil and atmospheric trace metal levels by dendrochemical analysis.

The use of dendrochemistry for monitoring historical changes in trace metal deposition and mobilisation of metals in soils is evaluated. In experimental studies, mobilisation of trace metals in surface soil following deliberate acidification was recorded in sugar maple (Acer saccharum) tree-rings with minimal lateral movement between rings. Furthermore, positive correlations between wood (3 year section 1993-95) and foliar chemistry (mean concentration 1993-95) were found for Cd and Zn, but not for Cu and Ni, showing that mobility up the tree bole differs between metals. Even so, substantial lateral movement of elements between rings occurs in some species. Stable Pb isotope ratios in tree-rings were used to show that sacred fir (Abies religeosa) is not a useful monitor of Pb deposition because Pb accumulates in the heartwood. Numerous sophisticated analytical techniques are now used in dendrochemical studies, including laser ablation sampling in conjunction with inductively coupled plasma mass spectrometry that enable the multi-element analysis of extremely small tree-rings with low detection limits. Clearly, not all tree species are suitable for dendrochemical studies, but if careful sampling strategies are used and suitable tree species are chosen, the chemical analysis of tree-rings can provide information concerning historical changes in soil and atmospheric trace metal levels unavailable from any other source.

Journal Article↗

Indices of antioxidant status in rats subjected to wood smoke inhalation and/or thermal injury.

The present study investigated antioxidant status in lavage fluid, lung, liver, heart and kidney in a rat model to simulate an inhalation injury as might be encountered by firefighters and burn victims. Anesthetized rats received either a 20% total body surface area (TBSA) full thickness scald or a sham burn. After a 5 h recovery period, half of the animals in the burn or sham burn groups were exposed to cooled western bark (fir and pine) smoke for 16.25 min. The remaining rats in each group breathed room air. At 1, 12, 24, 48 and 96 h after exposure to the smoke, five rats from each of the four groups were euthanatized and lungs were lavaged by infusing three 5 ml aliquots of normal saline for evaluation of airway cellular content and lung wet to dry weight ratios to estimate lung water content. A second series of five rats/group per time point were euthanatized at the above times and lung, liver, kidney and heart were removed for evaluation of tissue antioxidant enzyme activities and for thiobarbituric acid reactive substances (TBARS) concentrations, as well as for lung histology. Smoke exposure resulted in average plasma carboxyhemoglobin (COHb) of 19+/-2% in the two smoke exposed groups and produced areas of erosion of the tracheal surface, resulting in loss of epithelium and exposed basement membrane. Lung water content was not significantly different among the four groups during the 96-h experimental period. Lung TBARS levels were 2-3-fold higher at 12 h in smoke exposed rats compared with controls. These levels peaked at 24 h and remained significantly elevated at 48 h compared to controls. TBARS were also elevated in liver, but not in heart or kidney in response to burn or combined injury. Minor effects on lung antioxidant enzyme activities were observed after smoke inhalation. These data suggest that smoke inhalation, independent of burn injury, induces an oxidant stress that persists for at least the first 48 h after smoke exposure.

Animals↗

Application of standardized mistletoe extracts augment immune response and down regulates metastatic organ colonization in murine models.

The immunomodulatory and antimetastatic activity of standardized aqueous mistletoe extracts from plants grown on fir trees (ME-A) and pine trees (ME-P) were evaluated in BALB/c-mice. Regular subcutaneous (s.c.) and intraperitoneal (i.p.) applications (three times per week for 14 consecutive days; 5 and 50 microg per injection and mouse) upregulated thymus weight and peripheral blood leukocyte counts in tumor bearing mice. To check the influence of ME-A and ME-P treatment on growth of experimental metastases, RAW 117 H 10 lymphosarcoma cells and L-1 sarcoma cells were intravenously inoculated into BALB/c-mice to establish liver and lung colonization. ME-A and ME-P were regularly administered starting 24 h after tumor cell challenge. Organ colonization was investigated on day 14 after tumor cell inoculation and demonstrated statistically significant (P<0.05) reductions of experimental liver and lung metastases for ME-A and ME-P treated mice.

Adjuvants, Immunologic↗

Effect of an external resistance to airflow on the inspiratory flow curve.

Inhalation is a convenient way to deliver drugs to the respiratory tract in the treatment of respiratory diseases. For dry powder inhalers (DPI's), the principle of operation is to use the patient-generated inspiratory flow as energy source for emptying of the dose system and the delivery of fine drug particles into the respiratory tract. Resistance to airflow of the inhaler device is a major determinant for the inspiratory flow profile through the dry powder inhaler that can be generated by the patient. Therefore, resistance to airflow is one of the design parameters for DPI's, that could be used to control the inspiratory flow profile, and is one of the parameters to optimise particle deposition in the airways. In this study the effect of resistance to airflow on different parameters of the inspiratory flow curves as generated by healthy subjects, asthmatics and COPD patients was determined. As a result of increased resistance to airflow, the peak inspiratory flow (PIF), the flow increase rate (FIR) and the inhaled volume to reach PIF is decreased. On the other hand, the total inhalation time as well as the 80% dwell time is increased. In general, tuning of the resistance to airflow in the design of a dry powder inhaler may improve the drug deposition in the respiratory tract.

Administration, Inhalation↗

A complex-valued nonlinear neural adaptive filter with a gradient adaptive amplitude of the activation function.

A complex-valued nonlinear gradient descent (CNGD) learning algorithm for a simple finite impulse response (FIR) nonlinear neural adaptive filter with an adaptive amplitude of the complex activation function is proposed. This way the amplitude of the complex-valued analytic nonlinear activation function of a neuron in the learning algorithm is made gradient adaptive to give the complex-valued adaptive amplitude nonlinear gradient descent (CAANGD). Such an algorithm is beneficial when dealing with signals that have rich dynamical behavior. Simulations on the prediction of complex-valued coloured and nonlinear input signals show the gradient adaptive amplitude, CAANGD, outperforming the standard CNGD algorithm.

Algorithms↗

In vivo photodynamic therapy with the new near-IR absorbing water soluble photosensitizer lutetium texaphyrin and a high intensity pulsed light delivery system.

An in vivo fluorescence monitoring and photodynamic therapy (PDT) study was performed using the new photosensitizer lutetium texaphyrin (Lu-Tex). This photosensitizer is water soluble and has the additional advantage of strong absorption near 730 nm. C26 colon carcinoma was transplanted in the foot of BALB/c mice. In vivo fluorescence spectroscopy was applied to study Lu-Tex tissue distribution kinetics. For this purpose, fluorescence intensity both in the foot with the tumor and in the normal foot was measured in vivo by the laser-induced fluorescence (LIF) system. For PDT, both feet of the mice were irradiated simultaneously with the use of a new high intensity pulsed light delivery system, the Photodyne. The results of the LIF measurements showed that the maximal fluorescence intensity ratio between the normal and tumor bearing foot (FIR) was observed 24-48 h after the agent injection. Photoirradiation with doses from 90 to 240 J cm-2 (0.6 J cm-2 per 2 ms pulse, 1 Hz) 24 h after injection of Lu-Tex at a dose of 10 mg kg-1 caused significant tumor necrosis and delay in the tumor growth rate. The antitumor effect was enhanced with increasing light doses. Normal tissue response to PDT with Lu-Tex was determined as the damage index of the normal foot, which was irradiated simultaneously with the tumor bearing foot. The normal tissue response after PDT with Lu-Tex was compared with 5-aminolevulinic acid (ALA) induced protoporphyrin IX (PP), chlorin e6 (Chl) and Photofrin (PII) at the same values of antitumor effect. The results showed that at 50, 80 and 100% inhibition of tumor growth the orders of the values of normal foot damage indexes were as follows: ALA > Lu-Tex > or = PII > Chl, PII > ALA > Lu-Tex > Chl and PII > Lu-Tex > ALA > Chl respectively.

Animals↗

Resin-based defenses in conifers.

Bark beetle infestation and associated fungal infection are a serious disease problem in conifer species. Conifers have evolved elaborate, constitutive and inducible, terpene-based defense mechanisms to deter insect pests and their symbiotic fungal pathogens. This process involves the secretion of oleoresin, a complex mixture of monoterpenes, sesquiterpenes and diterpenoid acids. Induced oleoresinosis in grand fir (Abies grandis) provides a model system for studying the regulation of defensive terpene biosynthesis and for identifying relevant genes. The ecological relationships between conifers, beetle pests, beetle predators and fungal pathogens present several possible avenues for manipulating oleoresin composition to improve tree resistance. Possible examples include chemically disguising the host, adding toxins and altering the levels of pheromone precursors, attractants for predators or hormone mimics to disrupt insect development. Strategies and prospects for generating transgenic conifers with increased defense capability are discussed.

Journal Article↗