On-line screening of soil VOCs exchange responses to moisture, temperature and root presence

The exchanges of volatile organic compounds (VOCs) between soils and the atmosphere are poorly known. We investigated VOC exchange rates and how they were influenced by soil moisture, temperature and the presence of plant roots in a Mediterranean forest soil. We measured VOC exchange rates along a soil moisture gradient (5%–12.5%–20%–27.5% v/v) and a temperature gradient (10°C–15°C–25°C–35°C) using PTR-MS. Monoterpenes were identified with GC-MS. Soils were a sink rather than a source of VOCs in both soil moisture and temperature treatments (−2.16 ± 0.35 nmol m⁻² s⁻¹ and −4.90 ± 1.24 nmol m⁻² s⁻¹ respectively). Most compounds observed were oxygenated VOCs like alcohols, aldehydes and ketones and aromatic hydrocarbons. Other volatiles such as acetic acid and ethyl acetate were also observed. All those compounds had very low exchange rates (maximum uptake rates from −0.8 nmol m⁻² s⁻¹ to −0.6 nmol m⁻² s⁻¹ for methanol and acetic acid). Monoterpene exchange ranged only from −0.004 nmol m⁻² s⁻¹ to 0.004 nmol m⁻² s⁻¹ and limonene and α-pinene were the most abundant compounds. Increasing soil moisture resulted in higher soil sink activity possibly due to increases in microbial VOCs uptake activity. No general pattern of response was found in the temperature gradient for total VOCs. Roots decreased the emission of many compounds under increasing soil moisture and under increasing soil temperature. While our results showed that emission of some soil VOCs might be enhanced by the increases in soil temperature and that the uptake of most soil VOCs uptake might be reduced by the decreases of soil water availability, the low exchange rates measured indicated that soil-atmosphere VOC exchange in this system are unlikely to play an important role in atmospheric chemistry. Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Calcium dependence of the effects of abscisic acid on RNA synthesis during germination of Cicer arietinum seeds

The effect of abscisic acid (ABA) and CaCl₂ in the medium on RNA synthesis in embryonic axes of seeds of chick-pea (Cicer arietinum L. cv. Castellana) during the first hours of germination has been studied. ABA decreases the incorporation of ³H-uridine in the embryonic axes and modifies the mRNA populations by preventing the disappearance of three polypeptides of 25, 22 and 21.6 kDa and inducing the appearance of two polypeptides of 35 and 27 kDa absent in the control. Calcium increases the effect of ABA on the synthesis of these mRNAs and seems to be involved in the synthesis of at least the polypeptide of 25 kDa, as this polypeptide disappears in the treatments with EGTA and Verapamil. Moreover, cytosolic calcium seems to be necessary for the accumulation of these messengers since treatment with TMB-8 (chelating agent for endogenous calcium) decreases the intensity of the bands corresponding to these 5 polypeptides. The possible synergistic action of ABA and calcium in this process is discussed.     

Functional Characteristics of Pyruvate Transport inPhycomyces blakesleeanus

Jesús A. Marcos, Dolores de Arriaga, Félix Busto, and Joaquín Soler¹1997. Functional Characteristics of Pyruvate Transport inPhycomyces blakesleeanus. Fungal Genetics Biology25, 204-215. A saturable and accumulative transport system for pyruvate has been detected inPhycomyces blakesleeanusNRRL 1555(−) mycelium. It was strongly inhibited by α-cyano-4-hydroxycinnamate. -Lactate and acetate were competitive inhibitors of pyruvate transport. The initial pyruvate uptake velocity and accumulation ratio was dependent on the external pH. TheV_maxof transport greatly decreased with increasing pH, whereas the affinity of the carrier for pyruvate was not affected. The pyruvate transport system mediated its homologous exchange, which was essentially pH independent, and efflux, which increased with increasing external pH. The uptake of pyruvate was energy dependent and was strongly inhibited by inhibitors of oxidative phosphorylation and of the formation of proton gradients. Glucose counteracted the inhibitory effect of the pyruvate transport produced by inhibitors of mitochondrial ATP synthesis. Our results are consistent with a pyruvate/proton cotransport inP. blakesleeanusprobably driven by an electrochemical gradient of H⁺generated by a plasma membrane H⁺-ATPase.     

Expression of a gene encoding a ribosomal p40 protein and identification of an active promoter site

The promoter of a gene encoding a ribosome-associated protein of 40 kDa from Arabidopsis thaliana (A-p40) was sequenced and the expression of the gene studied. A-p40 was expressed in the same organs and with the same variations as the eukaryotic elongation factor 1 (eEF1A), another gene coding for a protein involved in translation Arabidopsis plants transformed with a -glucuronidase (GUS) gene driven by the A-p40 promoter confirm that A-p40 is expressed in actively dividing and growing cells. eEF1A promoter-GUS fusions have the same pattern of expression. Comparison of cis-acting elements from A-p40 and eEF1A revealed some common elements. A-p40 promoter deletions and transient gene expression in transfected Arabidopsis protopasts allowed the identification of trap40, a cis-acting element regulating gene expression. Gel retardation experiments indicate that eEF1A and A-p40 are regulated by different cis-acting elements. The role of such elements is discussed.     

Muscular and intraocular pressure responses among ocular-hypertensive subjects: Is there a rationale for biofeedback?

Several animal and human investigations have indicated that intraocular pressure (IOP) levels may be associated with extreme drug-induced changes in the extraocular muscles. Further, recent data suggest that, among individuals with normal IOP level, moderate increases in facial muscle (EMG) activity around the eye while the eye is open are associated with increases in IOP. To investigate further the relationship between facial EMG activity and IOP levels and to examine a group of individuals with elevated IOP levels, subjects were recruited from outpatients at an optometry clinic. Three groups of subjects were selected: a group of ocular hypertensive subjects who showed elevated pressures at the optometry clinic and upon the day of testing, a group of labile ocular hypertensive subjects who evinced elevated pressures during their visit to the optometry clinic but lower pressures on the day of testing, and a group of normal IOP subjects who showed normal pressures both during their optometry clinic visit and on the day of testing. To investigate anxiety differences, subjects were administered the State-Trait Anxiety Inventory, but subsequent analysis revealed no group differences. To evaluate the role of stress upon muscle (EMG) functioning around the eye, subjects were subjected to imagery and standardized mental arithmetic stressors; analyses of these results also revealed no significant group differences. Finally, subjects were given EMG biofeedback for muscle activity around the eye while IOP was assessed during five alternating periods in which they made decreases and increases in EMG activity. Results revealed significant group, period, and group by period interaction effects. The pattern of results is interpreted as implicating EMG activity in IOP fluctuations; the implications of these data for potential biofeedback and stress management treatments are discussed.This research was supported by a Faculty Research Grant of the University of Alabama at Birmingham.     

Functional and Morphological Correlates in the Drosophila LRRK2 loss-of-function Model of Parkinson’s Disease: Drug Effects of Withania somnifera (Dunal) Administration

The common fruit fly Drosophila melanogaster (Dm) is a simple animal species that contributed significantly to the development of neurobiology whose leucine-rich repeat kinase 2 mutants (LRRK2) loss-of-function in the WD40 domain represent a very interesting tool to look into physiopathology of Parkinson’s disease (PD). Accordingly, LRRK2 Dm have also the potential to contribute to reveal innovative therapeutic approaches to its treatment. Withania somnifera Dunal, a plant that grows spontaneously also in Mediterranean regions, is known in folk medicine for its anti-inflammatory and protective properties against neurodegeneration. The aim of this study was to evaluate the neuroprotective effects of its standardized root methanolic extract (Wse) on the LRRK2 loss-of-function Dm model of PD. To this end mutant and wild type (WT) flies were administered Wse, through diet, at different concentrations as larvae and adults (L⁺/A⁺) or as adults (L^-/A⁺) only. LRRK2 mutants have a significantly reduced lifespan and compromised motor function and mitochondrial morphology compared to WT flies 1% Wse-enriched diet, administered to Dm LRRK2 as L^-/A⁺and improved a) locomotor activity b) muscle electrophysiological response to stimuli and also c) protected against mitochondria degeneration. In contrast, the administration of Wse to Dm LRRK2 as L⁺/A⁺, no matter at which concentration, worsened lifespan and determined the appearance of increased endosomal activity in the thoracic ganglia. These results, while confirming that the LRRK2 loss-of-function in the WD40 domain represents a valid model of PD, reveal that under appropriate concentrations Wse can be usefully employed to counteract some deficits associated with the disease. However, a careful assessment of the risks, likely related to the impaired endosomal activity, is required.     

Evaluating evolutionary pressures and phylogenetic signal in earthworms: a case study – the number of typhlosole lamellae in Hormogastridae (Annelida,Oligochaeta)

Rarely have phylogenetic comparative methods been used to study the correlation between phenotypic traits and environmental variables in invertebrates. With the widespread convergence and conservativeness of the morphological characters used in earthworms, these comparative methods could be useful to improve our understanding of their evolution and systematics. One of the most prominent morphological characters in the family Hormogastridae, endemic to Mediterranean areas, is their multilamellar typhlosole, traditionally thought to be an adaptation to soils poor in nutrients. We tested the correlation of body size and soil characteristics with the number of typhlosole lamellae through a phylogenetic generalized least squares (PGLS) analysis. An ultrametric phylogenetic hypothesis was built with a 2580‐bp DNA sequence from 90 populations, used in combination with three morphological and 11 soil variables. The best‐supported model, based on the Akaike information criterion, was obtained by optimizing the parameters lambda (λ), kappa (κ), and delta (δ). The phylogenetic signal was strong for the number of typhlosole lamellae and average body weight, and was lower for soil variables. Increasing body weight appeared to be the main evolutionary pressure behind the increase in the number of typhlosole lamellae, with soil texture and soil richness having a weaker but significant effect. Information on the evolutionary rate of the number of typhlosole lamellae suggested that the early evolution of this character could have strongly shaped its variability, as is found in an adaptive radiation. This work highlights the importance of implementing the phylogenetic comparative method to test evolutionary hypotheses in invertebrate taxa.     

Adherence to Mediterranean diet is associated with methylation changes in inflammation-related genes in peripheral blood cells

Epigenetic processes, including DNA methylation, might be modulated by environmental factors such as the diet, which in turn have been associated with the onset of several diseases such as obesity or cardiovascular events. Meanwhile, Mediterranean diet (MedDiet) has demonstrated favourable effects on cardiovascular risk, blood pressure, inflammation and other complications related to excessive adiposity. Some of these effects could be mediated by epigenetic modifications. Therefore, the objective of this study was to investigate whether the adherence to MedDiet is associated with changes in the methylation status from peripheral blood cells. A subset of 36 individuals was selected within the Prevención con Dieta Mediterránea (PREDIMED)-Navarra study, a randomised, controlled, parallel trial with three groups of intervention in high cardiovascular risk volunteers, two with a MedDiet and one low-fat control group. Changes in methylation between baseline and 5 years were studied. DNA methylation arrays were analysed by several robust statistical tests and functional classifications. Eight genes related to inflammation and immunocompetence (EEF2, COL18A1, IL4I1, LEPR, PLAGL1, IFRD1, MAPKAPK2, PPARGC1B) were finally selected as changes in their methylation levels correlated with adherence to MedDiet and because they presented sensitivity related to a high variability in methylation changes. Additionally, EEF2 methylation levels positively correlated with concentrations of TNF-α and CRP. This report is apparently the first showing that adherence to MedDiet is associated with the methylation of the reported genes related to inflammation with a potential regulatory impact.     

Endopolygalacturonase PG1 in Different Formae Speciales of Fusarium oxysporum

PG1, the major endopolygalacturonase of the vascular wilt pathogen Fusarium oxysporum, was secreted during growth on pectin by 10 of 12 isolates belonging to seven formae speciales, as determined with isoelectric focusing zymograms and sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels. A Southern analysis of genomic DNA and PCR performed with gene-specific primers revealed that the pg1 locus was highly conserved structurally in most isolates. Two PG1-deficient isolates were identified; one lacked the encoding gene, and the other carried a pg1 allele disrupted by a 3.2-kb insertion with sequence homology to hAT transposases. The virulence for muskmelon of different F. oxysporum f. sp. melonis isolates was not correlated with PG1 production in vitro. We concluded that PG1 is widely distributed in F. oxysporum and that it is not essential for pathogenicity.