Río Tinto (Huelva, Spain) is located in one of the most important mining regions in the world. Its soils are characterized
by their extreme acidity and elevated concentrations of heavy metals. Due to these characteristics, the Tinto ecosystem is
considered unique and an ideal location to study biological adaptations to this type of habitat. Plant species that present
these adaptations might be useful to mining and other metal pollution restoration programs. This study reports the results
for the screening of Ca, Mg, Na, Mn, Fe, Ni, Cu, Zn, As, and Pb in aerial tissues of 97 plant species from the Tinto basin
flora. In addition, plant–soil relationships were analyzed using the biological absorption coefficient (BAC) to detect the
main plant adaptations in the Tinto flora. The species selected are representative of the biomass of the main dominant edaphophile
and climatophile vegetation communities of the three river sections, forest, and subseral stages. Plant and soil elemental
analyses were performed using inductively coupled plasma–mass spectrometry technique (ICP-MS). The results indicate that in
general, Tinto flora shows a pattern of accumulation of the analyzed elements in aerial tissues which agrees with the nutritional
requirements of vascular plants (macronutrients > micronutrients > indifferent or toxic elements). Among macronutrients, Ca
seems to be an essential element in this habitat. This element accumulates in the aerial plant tissues. Basically, the Río
Tinto flora is made of Fe, Cu, Zn, Ni, As, and Pb excluders, although some analyzed species of Erica, Quercus, Lavandula, Cistus, Genista, and Cytisus genera can be considered Mn accumulators. The results of this study make up a body of fundamental knowledge of the strategies
used by plants to thrive in habitats with high concentrations of toxic heavy metals. This information is vital when it comes
to planning a restoration program. Plants must be selected and used according to the requirements, always respecting the characteristics
of the territory and facilitating the development of suitable vegetation. 相似文献
Inorganic arsenic [iAs, As(III) + As(V)] is considered a human carcinogen. Recent studies show that it has also toxic effects on the intestinal epithelium which might partly explain its systemic toxicity. The aim of this study is to evaluate the protective role of lactic acid bacteria (LAB) against the toxic effects of iAs on the intestinal epithelium. For this purpose, the human colonic cells Caco-2 were exposed to As(III) in the presence of various LAB strains or their conditioned medium. Results showed that some strains and their conditioned media partially revert the oxidative stress, the production of pro-inflammatory cytokines, the alterations of the distribution of tight junction proteins, and the cell permeability increases caused by As(III). These results show that both soluble factors secreted or resulting from LAB metabolism and cell-cell interactions are possibly involved in the beneficial effects. Therefore, some LAB strains have potential as protective agents against iAs intestinal barrier disruption.
Human umbilical endothelial cells in culture retain differentiated morphological and functional characterization in primary culture and even in the early subcultures, after which they begin to degenerate. We have studied the morphological and biochemical characterization (ability to produce prostacyclin, prostaglandin E2 and thromboxane A2 in culture) of endothelial cells in the first seven subcultures. In addition the influence of serum and endothelial cell growth factor added to the culture medium have been evaluated. With 20% normal human serum, cell proliferation is faster than with the same concentration of human fetal or bovine fetal serum.After the 3rd passage, morphological and growth alterations become observable in the endothelial cells. However, prostacyclin, prostaglandin E2 and thromboxane A2 production showed no variations during the study. 相似文献
Circulating endothelial cells and microparticles have prognostic value in cancer, and might be predictors of response to chemotherapy and antiangiogenic treatments. We have investigated the prognostic value of circulating endothelial cells and microparticles in patients treated for advanced non-small cell lung cancer.
Methodology/Principal Findings
Peripheral blood samples were obtained from 60 patients before first line, platinum-based chemotherapy +/− bevacizumab, and after the third cycle of treatment. Blood samples from 60 healthy volunteers were also obtained as controls. Circulating endothelial cells were measured by an immunomagnetic technique and immunofluorescence microscopy. Phosphatidylserine-positive microparticles were evaluated by flow cytometry. Microparticle-mediated procoagulant activity was measured by the endogen thrombin generation assay. Results: pre- and posttreatment levels of markers were higher in patients than in controls (p<0.0001). Elevated levels of microparticles were associated with longer survival. Elevated pretreatment levels of circulating endothelial cells were associated with shorter survival.
Conclusions/Significance
Circulating levels of microparticles and circulating endothelial cells correlate with prognosis, and could be useful as prognostic markers in patients with advanced non-small cell lung cancer. 相似文献
Statins may have beneficial effects in atherogenesis given their antithrombotic properties involving non-lipid mechanisms
that modify endothelial function of tissue factor induction by thrombin. In this study, we investigate the effect of atorvastatin
on tissue factor (TF) activity in thrombin-stimulated endothelial cells and its regulation through mevalonate or its derivatives.
First subculture of human umbilical endothelial cells was used for this study. Cells were treated with thrombin and atorvastatin
for different time intervals and dosage. Tissue factor activity was measured as Factor Xa generation induced by Tissue Factor-Factor
VIIa complex on confluent cells. Our results show that atorvastatin prevents the thrombin-induced up-regulation of tissue
factor activity in a concentration-dependent manner. Mevalonate and geranylgeranyl pyrophosphate reversed this inhibitory
effect of atorvastatin on tissue factor activity, while the presence of farnesyl pyrophosphate did not prevent the atorvastatin
effect on thrombin-induced tissue factor activity. Rho-kinase inhibitor did not affect the thrombin stimulation of tissue
factor activity. High amount of hydrophobic isoprenoid groups decreases the thrombin-induced TF activity and may promote endothelial
cell anti-thrombotic action. Rho kinase pathways do not have a major role in the thrombin-mediated TF activity. The inhibitory
effect of atorvastatin on thrombin-induced TF activity was partially reversed by MVA and GGPP but not FPP. 相似文献
A comparative study of the roots, rhizomes and leaves of an iron hyperaccumulator plant, Imperata cylindrica, isolated from the banks of an extreme acidic environment, using complementary techniques: Mösbauer spectroscopy (MS), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled to energy-dispersive X-ray microanalysis (EDAX) and transmission electron microscopy (TEM), has shown that two main biominerals, jarosite and ferrihydrate-ferritin, accumulate in the different tissues. Jarosite accumulates mainly in roots and rhizomes, while ferritin has been detected in all the structures. A model of iron management in I. cylindrica is presented. 相似文献
The nature reserve of Tehuacan-Cuicatlan in central Mexico is known for its diversity and endemism mainly in cactus plants.
Although the xerophytic flora is reasonably documented, the bacterial communities associated with these species have been
largely neglected. We assessed the diversity and composition of bacterial communities in bulk (non-rhizospheric) soil and
the rhizosphere of three cactus plant species: Mammillaria carnea, Opuntia pilifera and Stenocereus stellatus, approached using cultivation and molecular techniques, considering the possible effect of dry and rainy seasons. Cultivation-dependent
methods were focused on putative N2-fixers and heterotrophic aerobic bacteria, in the two media tested the values obtained for dry season samples grouped together
regardless of the sample type (rhizospheric or non-rhizospheric), these groups also included the non-rhizospheric sample for
rainy season, on each medium. These CFU values were smaller and significantly different from those obtained on rhizospheric
samples from rainy season. Genera composition among isolates of the rhizospheric samples was very similar for each season,
the most abundant taxa being α-Proteobacteria, Actinobacteria and Firmicutes. Interestingly, the genus Ochrobactrum was highly represented among rhizospheric samples, when cultured in N-free medium. The structure of the bacterial communities
was approached with molecular techniques targeting partial 16S rRNA sequences such as denaturing gradient gel electrophoresis
and serial analysis of ribosomal sequence tags. Under these approaches, the most represented bacterial phyla were Actinobacteria,
Proteobacteria and Acidobacteria. The first two were also highly represented when using isolation techniques. 相似文献
Serotonin induces fluid secretion from Calliphora salivary glands by the parallel activation of the InsP3/Ca2+ and cAMP signaling pathways. We investigated whether cAMP affects 5-HT-induced Ca2+ signaling and InsP3-induced Ca2+ release from the endoplasmic reticulum (ER).
Results
Increasing intracellular cAMP level by bath application of forskolin, IBMX or cAMP in the continuous presence of threshold 5-HT concentrations converted oscillatory [Ca2+]i changes into a sustained increase. Intraluminal Ca2+ measurements in the ER of β-escin-permeabilized glands with mag-fura-2 revealed that cAMP augmented InsP3-induced Ca2+ release in a concentration-dependent manner. This indicated that cAMP sensitized the InsP3 receptor Ca2+ channel for InsP3. By using cAMP analogs that activated either protein kinase A (PKA) or Epac and the application of PKA-inhibitors, we found that cAMP-induced augmentation of InsP3-induced Ca2+ release was mediated by PKA not by Epac. Recordings of the transepithelial potential of the glands suggested that cAMP sensitized the InsP3/Ca2+ signaling pathway for 5-HT, because IBMX potentiated Ca2+-dependent Cl- transport activated by a threshold 5-HT concentration.
Conclusion
This report shows, for the first time for an insect system, that cAMP can potentiate InsP3-induced Ca2+ release from the ER in a PKA-dependent manner, and that this crosstalk between cAMP and InsP3/Ca2+ signaling pathways enhances transepithelial electrolyte transport. 相似文献
Left ventricular (LV) remodelling after myocardial infarction (MI) is a crucial determinant of the clinical course of heart failure. Matrix metalloproteinase (MMP) activation is strongly associated with LV remodelling after MI. Elucidation of plasma membrane receptors related to the activation of specific MMPs is fundamental for treating adverse cardiac remodelling after MI. The aim of current investigation was to explore the potential association between the low‐density lipoprotein receptor‐related protein 1 (LRP1) and MMP‐9 and MMP‐2 spatiotemporal expression after MI. Real‐time PCR and Western blot analyses showed that LRP1 mRNA and protein expression levels, respectively, were significantly increased in peri‐infarct and infarct zones at 10 and 21 days after MI. Confocal microscopy demonstrated high colocalization between LRP1 and the fibroblast marker vimentin, indicating that LRP1 is mostly expressed by cardiac fibroblasts in peri‐infarct and infarct areas. LRP1 also colocalized with proline‐rich tyrosine kinase 2 (pPyk2) and MMP‐9 in cardiac fibroblasts in ischaemic areas at 10 and 21 days after MI. Cell culture experiments revealed that hypoxia increases LRP1, pPyk2 protein levels and MMP‐9 activity in fibroblasts, without significant changes in MMP‐2 activity. MMP‐9 activation by hypoxia requires LRP1 and Pyk2 phosphorylation in fibroblasts. Collectively, our in vivo and in vitro data support a major role of cardiac fibroblast LRP1 levels on MMP‐9 up‐regulation associated with ventricular remodelling after MI. 相似文献
Silicon concentration, distribution, and ultrastructure of silicon deposits in the Poaceae Imperata cylindrica (L.) P. Beauv. have been studied. This grass, known for its medicinal uses and also for Fe hyperaccumulation and biomineralization capacities, showed a concentration of silicon of 13,705?±?9,607 mg/kg dry weight. Silicon was found as an important constituent of cell walls of the epidermis of the whole plant. Silica deposits were found in silica bodies, endodermis, and different cells with silicon-collapsed lumen as bulliforms, cortical, and sclerenchyma cells. Transmission electron microscope observations of these deposits revealed an amorphous material of an ultrastructure similar to that previously reported in silica bodies of other Poaceae. 相似文献