Jatropha curcas and assisted phytoremediation of a mine tailing with biochar and a mycorrhizal fungus

Soil pollution is an important ecological problem worldwide. Phytoremediation is an environmental-friendly option for reducing metal pollution. A greenhouse experiment was conducted to determine the growth and physiological response, metal uptake, and the phytostabilization potential of a nontoxic Jatropha curcas L. genotype when grown in multimetal-polluted conditions. Plants were established on a mine residue (MR) amended or not amended with corn biochar (B) and inoculated or not inoculated with the mycorrhizal fungus Acaulospora sp. (arbuscular mycorrhizal fungus, AMF). J. curcas was highly capable of growing in an MR and showed no phytotoxic symptoms. After J. curcas growth (105 days), B produced high desorption of Cd and Pb from the MR; however, no increases in metal shoot concentrations were observed. Therefore, Jatropha may be useful for phytostabilization of metals in mine tailings. The use of B is recommended because improved MR chemical properties conduced to plant growth (cation-exchange capacity, organic matter content, essential nutrients, electrical conductivity, water-holding capacity) and plant growth development (higher biomass, nutritional and physiological performance). Inoculation with an AMF did not improve any plant growth or physiological plant characteristic. Only higher Zn shoot concentration was observed, but it was not phytotoxic. Future studies of B use and its long-term effect on MR remediation should be conducted under field conditions.     

Protective effects of resveratrol on calcium-induced oxidative stress in rat heart mitochondria

Trans-resveratrol is a nutraceutical with known antioxidant, anti-inflammatory, cardioprotective, and anti-apoptotic properties. The aim of this study was to evaluate the effects of resveratrol on heart mitochondria. Resveratrol significantly decreased Fe²⁺ + ascorbate oxidant system-induced lipid peroxide levels, preserved physiological levels of glutathione, and increased nitric oxide (NO) levels in mitochondria. Under calcium-mediated stress, there was a 2.7-fold increase in the NO levels, and a mild decoupling in the mitochondrial respiratory chain. These results provide a mechanism for and support the beneficial effects of resveratrol under pathological conditions induced by oxidative stress and calcium overload. In addition, these findings underscore the usefulness of resveratrol in the prevention of cardiovascular diseases.     

Understanding the Interaction of Rural People with Ecosystems: A Case Study in a Tropical Dry Forest of Mexico

The aim of this study was to help understand the interaction of rural people with tropical dry forests. It was based on social research conducted in the Chamela-Cuixmala region, on the Pacific coast of Mexico. The analytical tools used in the study included stakeholder identification, environmental history and social perceptions. The two main social groups in the study were ejidatarios, who own most of the territory, and avecindados, who possess no land but have high population numbers. Through an interpretative methodological approach we documented the vision and meaning that rural people give to their natural and social worlds. The agricultural development model promoted by the Mexican government for decades was identified as the main driver of ecosystem transformation. Rural people, who arrived recently in the region, were proud of the pasture-lands that were transformed from tropical forests. Conservation policies implemented during the last two decades were viewed as impositions although people recognized the value of services provided by ecosystems. This case study has helped to unravel the main dimensions of the human system and how it relates to structures of signification. The social panorama unveiled can be used as an initial basis to promote further research on the social-ecological system of the Chamela-Cuixmala region and to develop future participatory management schemes.     

Oxidative/Nitrative Stress and Inflammation Drive Progression of Doxorubicin-Induced Renal Fibrosis in Rats as Revealed by Comparing a Normal and a Fibrosis-Resistant Rat Strain

Chronic renal fibrosis is the final common pathway of end stage renal disease caused by glomerular or tubular pathologies. Genetic background has a strong influence on the progression of chronic renal fibrosis. We recently found that Rowett black hooded rats were resistant to renal fibrosis. We aimed to investigate the role of sustained inflammation and oxidative/nitrative stress in renal fibrosis progression using this new model. Our previous data suggested the involvement of podocytes, thus we investigated renal fibrosis initiated by doxorubicin-induced (5 mg/kg) podocyte damage. Doxorubicin induced progressive glomerular sclerosis followed by increasing proteinuria and reduced bodyweight gain in fibrosis-sensitive, Charles Dawley rats during an 8-week long observation period. In comparison, the fibrosis-resistant, Rowett black hooded rats had longer survival, milder proteinuria and reduced tubular damage as assessed by neutrophil gelatinase-associated lipocalin (NGAL) excretion, reduced loss of the slit diaphragm protein, nephrin, less glomerulosclerosis, tubulointerstitial fibrosis and matrix deposition assessed by periodic acid–Schiff, Picro-Sirius-red staining and fibronectin immunostaining. Less fibrosis was associated with reduced profibrotic transforming growth factor-beta, (TGF-β1) connective tissue growth factor (CTGF), and collagen type I alpha 1 (COL-1a1) mRNA levels. Milder inflammation demonstrated by histology was confirmed by less monocyte chemotactic protein 1 (MCP-1) mRNA. As a consequence of less inflammation, less oxidative and nitrative stress was obvious by less neutrophil cytosolic factor 1 (p47^phox) and NADPH oxidase-2 (p91^phox) mRNA. Reduced oxidative enzyme expression was accompanied by less lipid peroxidation as demonstrated by 4-hydroxynonenal (HNE) and less protein nitrosylation demonstrated by nitrotyrosine (NT) immunohistochemistry and quantified by Western blot. Our results demonstrate that mediators of fibrosis, inflammation and oxidative/nitrative stress were suppressed in doxorubicin nephropathy in fibrosis-resistant Rowett black hooded rats underlying the importance of these pathomechanisms in the progression of renal fibrosis initiated by glomerular podocyte damage.     

Genetic corroboration of Engraulis mordax larvae in the upper Gulf of California,a previously undescribed spawning habitat

Ichthyological Research - Larvae of the Californian anchovy (Engraulis mordax) in the upper Gulf of California were identified. The finding was achieved with partial sequences of 16S rRNA...     

Nuclear and chloroplast DNA phylogeography reveals vicariance among European populations of the model species for the study of metal tolerance, Arabidopsis halleri (Brassicaceae)

Arabidopsis halleri is a pseudometallophyte involved in numerous molecular studies of the adaptation to anthropogenic metal stress. In order to test the representativeness of genetic accessions commonly used in these studies, we investigated the A. halleri population genetic structure in Europe. Microsatellite and nucleotide polymorphisms from the nuclear and chloroplast genomes, respectively, were used to genotype 65 populations scattered over Europe. The large-scale population structure was characterized by a significant phylogeographic signal between two major genetic units. The localization of the phylogeographic break was assumed to result from vicariance between large populations isolated in southern and central Europe, on either side of ice sheets covering the Alps during the Quaternary ice ages. Genetic isolation was shown to be maintained in western Europe by the high summits of the Alps, whereas admixture was detected in the Carpathians. Considering the phylogeographic literature, our results suggest a distinct phylogeographic pattern for European species occurring in both mountain and lowland habitats. Considering the evolution of metal adaptation in A. halleri, it appears that recent adaptations to anthropogenic metal stress that have occurred within either phylogeographic unit should be regarded as independent events that potentially have involved the evolution of a variety of genetic mechanisms.     

Toxicity and metabolism of the chloral-derived mammalian alkaloid 1-trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo) in PC12 cells

Chloral-derived beta-carbolines, which are structurally similar to the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 5), are discussed to contribute to neuronal cell death in idiopathic Parkinson's disease. The cytotoxicity of 1-trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo, 4) to neuronal-like clonal pheochromocytoma PC12 cells was examined by the determination of lactate dehydrogenase (LDH) release. After incubation for 48 h, 4 showed a strong dose-dependent cytotoxic activity towards PC12 cells with an ED50 value of 230 microM. In PC12 cells reductive dehalogenation of 4 was observed giving rise to the formation of 1-dichloromethyl-1,2,3,4-tetrahydro-beta-carboline (6) as a main TaClo metabolite exhibiting a cytotoxic potential comparable to that of TaClo. An X-ray structure analysis, performed for the trifluoroacetyl derivative of 6, revealed the N-substituent of such a highly chlorinated agent to be dramatically pushed out of the beta-carboline ring 'plane' due to the high steric demand of the huge dichloromethyl group at C(1).     

Tyrosine 39 of GH13 <Emphasis Type="Italic">α</Emphasis>-amylase from <Emphasis Type="Italic">Thermococcus hydrothermalis</Emphasis> contributes to its thermostability

The presented work is focused on the naturally thermostable α-amylase from the archaebacterium Thermococcus hydrothermalis. From the evolutionary point of view, the archaeal α-amylases are most closely related to plant α-amylases. In a wider sense, especially when the evolutionary trees are based on the less conserved part of their amino acid sequences (e.g. domain C succeeding the catalytic TIM-barrel), also the representatives of bacterial liquefying (Bacillus licheniformis) and saccharifying (Bacillus subtilis) α-amylases as well as the one from Thermotoga maritima should be included into the relatedness with the archaeal and plant α-amylases. Based on the bioinformatics analysis of the α-amylase from T. hydrothermalis, the position of tyrosine 39 (Y16 if the putative 23-residue long signal peptide is considered) was mutated to isoleucine (present in the α-amylase from T. maritima) by the in vitro mutagenesis. The biochemical characterization of the wild-type α-amylase and its Y39I mutant revealed that: (i) the specific activity of both enzymes was approximately equivalent (0.55 ± 0.13 U/mg for the wild-type and 0.52 ± 0.15 U/mg for the Y39I); (ii) the mutant exhibited decreased temperature optimum (from 85°C for the wild-type to 80°C for the Y39I); and (iii) the pH optimum remained the same (pH 5.5 for both enzymes). The remaining activity of the α-amylases was also tested by one-hour incubation at 80°C, 85°C, 90°C and 100°C. Since the wild-type α-amylase lost only 13% of its activity after one-hour incubation at the highest tested temperature (100°C), whereas 27% decrease was seen for the mutant Y39I under the same conditions, it is possible to conclude that the position of tyrosine 39 could contribute to the thermostability of the α-amylase from T. hydrothermalis.     

1-Trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo) and related derivatives: chemistry and biochemical effects on catecholamine biosynthesis

1-Trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo, 2) is a mammalian alkaloid that readily originates in the human organism, by Pictet-Spengler condensation of endogenously present tryptamine (Ta) and the non-natural hypnotic agent trichloroacetaldehyde (chloral, Clo). Due to its structural analogy to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 1), TaClo is discussed to possibly contribute to the pathogenesis of Parkinson's disease acting as an environmental toxin. Previous investigations on rats and neuronal cell cultures revealed 2 to be capable of inducing severe disturbances on the dopamine metabolism. In this paper, we report on the effects of 2 on the activity of tyrosine hydroxylase [L-tyrosine, tetrayhydropteridine/oxygen oxidoreductase (3-hydroxylating), EC 1.14,16.2; TH] in vitro using rat brain homogenates prepared from the TH-rich nucleus accumbens. TaClo (2) dose-dependently inhibited basal TH activity (IC(50)=3 microM), and after enzyme activation by pituitary adenylate cyclase-activating polypeptide (PACAP-27), it also reduced L-DOPA formation (IC(50)=15 microM). Moreover, two presumable TaClo metabolites, 2-methyl-TaClo (N-Me-TaClo, 3) and 1-dichloromethylene-1,2,3,4-tetrahydro-beta-carboline (1-CCl(2)-TH beta C, 4), which were synthesized in good yields, also proved to be potent inhibitors of TH, with the strongest effect on basal activity (similar to TaClo) being observed for 3 (IC(50)=3 microM). In contrast to TaClo, however, 3 and 4 showed biphasic effects after TH activation with PACAP-27, inducing a marked increase of enzyme activity in the nanomolar range (<0.1 microM), while TH activity was nearly completely blocked at high concentrations (IC(100)=0.1mM). An X-ray diffraction investigation on the 3-dimensional structure of the 1-CCl(2)-TH beta C-derived trifluoroacetamide 7 revealed the voluminous and quite rigid dichloromethylene substituent to be only moderately twisted out of the beta-carboline ring 'plane', thus resulting in an increased ring strain of the partially hydrogenated pyrido moiety accompanied by a strong steric hindrance of Cl(1), Cl(2), C(13), and N(2), which pushes the N-trifluoroacetyl group upwards to an even higher extent than for the TaClo-related trifluoroacetamide 8.