Structures of bioactive carexanes from the roots of Carex distachya Desf

Four metabolites, named carexanes I-L, have been isolated from the roots of Carex distachya Desf, an herbaceous plant living in the Mediterranean maquis, together with three known compounds, already isolated from the aerial part of the plant. All the compounds have been characterized on the basis of their spectroscopic properties. Carexane I derived from the lose of a proton from the C-18 carbon of an intermediate isopropyl cation. Its stereostructure has been elucidated by Mosher's method, NOESY/ROESY experiments and computational calculations. The bioactivity on seed germination and root/shoot growth of Lactuca sativa L. of all the isolated compounds is also reported.     

Capillary Regeneration in Scleroderma: Stem Cell Therapy Reverses Phenotype?

Background

Scleroderma is an autoimmune disease with a characteristic vascular pathology. The vasculopathy associated with scleroderma is one of the major contributors to the clinical manifestations of the disease.

Methodology/Principal Findings

We used immunohistochemical and mRNA in situ hybridization techniques to characterize this vasculopathy and showed with morphometry that scleroderma has true capillary rarefaction. We compared skin biopsies from 23 scleroderma patients and 24 normal controls and 7 scleroderma patients who had undergone high dose immunosuppressive therapy followed by autologous hematopoietic cell transplant. Along with the loss of capillaries there was a dramatic change in endothelial phenotype in the residual vessels. The molecules defining this phenotype are: vascular endothelial cadherin, a supposedly universal endothelial marker required for tube formation (lost in the scleroderma tissue), antiangiogenic interferon α (overexpressed in the scleroderma dermis) and RGS5, a signaling molecule whose expression coincides with the end of branching morphogenesis during development and tumor angiogenesis (also overexpressed in scleroderma skin. Following high dose immunosuppressive therapy, patients experienced clinical improvement and 5 of the 7 patients with scleroderma had increased capillary counts. It was also observed in the same 5 patients, that the interferon α and vascular endothelial cadherin had returned to normal as other clinical signs in the skin regressed, and in all 7 patients, RGS5 had returned to normal.

Conclusion/Significance

These data provide the first objective evidence for loss of vessels in scleroderma and show that this phenomenon is reversible. Coordinate changes in expression of three molecules already implicated in angiogenesis or anti-angiogenesis suggest that control of expression of these three molecules may be the underlying mechanism for at least the vascular component of this disease. Since rarefaction has been little studied, these data may have implications for other diseases characterized by loss of capillaries including hypertension, congestive heart failure and scar formation.     

The role of alien fish (the centrarchid Micropterus salmoides) in lake food webs highlighted by stable isotope analysis

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Microarray analysis of replicate populations selected against a wing-shape correlation in Drosophila melanogaster

We selected bidirectionally to change the phenotypic correlation between two wing dimensions in Drosophila melanogaster and measured gene expression differences in late third instar wing disks, using microarrays. We tested an array of 12 selected lines, including 10 from a Massachusetts population (5 divergently selected pairs) and 2 from a California population (1 divergently selected pair). In the Massachusetts replicates, 29 loci showed consistent, significant expression differences in all 5 line-pair comparisons. However, the significant loci in the California lines were almost completely different from these. The disparity between responding genes in different gene pools confirms recent evidence that surprisingly large numbers of loci can affect wing shape. Our results also show that with well-replicated selection lines, of large effective size, the numbers of candidate genes in microarray-based searches can be reduced to realistic levels.     

Potential allelopathic effect of neo-clerodane diterpenes from Teucrium chamaedrys (L.) on stenomediterranean and weed cosmopolitan species

The allelopathic effects of neo-clerodane diterpenes, isolated from Teucrium chamaedrys (L.), have been evaluated on the seed germination and seedling growth of four coexisting Mediterranean species (Dactylis hispanica, Petrorhagia velutina, Phleum subulatum and Petrorhagia saxifraga) and two cosmopolitan weeds (Amaranthus retroflexus and Avena fatua). All of the structures have been elucidated on the basis of their spectroscopic features. The bioassays data, analyzed by principal component analysis, showed more negative effects on weeds respect to coexisting species. Moreover D. hispanica, P. velutina, P. subulatum showed both stimulating or inhibiting effects depending on the type of metabolite and the concentration used in the test.     

Inhibition of net nitrification activity in a Mediterranean woodland: possible role of chemicals produced by Arbutus unedo

Nitrification is a key biological process for the control of soil NO₃ ^? availability and N losses from terrestrial ecosystems. The study investigates the causes for the absence of net nitrification activity in the soil of a Mediterranean monospecific woodland of Arbutus unedo, focusing in particular on the possible role of chemicals produced by this plant. The mineral N pool, net rates of mineralization and nitrification were measured in the soil top 10 cm over 18 months. Raw extracts of leaves and roots of Arbutus unedo and soil underneath Arbutus plant canopy were purified using chromatographic techniques and the structure of chemicals was defined using spectroscopic and spectrometric methods. Leaf extracts (raw, aqueous and organic fractions) were tested for their toxicity on net nitrification, using a test soil. Field and laboratory incubations showed soil NO₃ ^? concentration below the detection limit over the whole study period, despite the significant NH₄ ⁺ availability. Toxicity tests indicated that more than 400 μg of extract g^?1 dry soil were needed to have more than 50% reduction of net NO₃ ^? production. Gallocatechin and catechin were among the most abundant chemicals in the extracts of leaves, roots and soil. Their soil concentration was significantly higher than the annual calculated input via leaf litter, and it was in the range of toxic concentrations, as deduced from the dose-response curve of the toxicity test. Data support the hypothesis that plant produced chemicals might be involved in the limited net nitrate production in this Mediterranean woodland.

     

The Anopheles gambiae salivary protein gSG6: An anopheline-specific protein with a blood-feeding role

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Structure elucidation and hepatotoxicity evaluation against HepG2 human cells of neo-clerodane diterpenes from Teucrium polium L

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