Biflavonoids from Daphne linearifolia Hart.

Two new biflavonoids, 2″-hydroxygenkwanol A (1) and 4′-methylgenkwanol A (2), together with fourteen known compounds were isolated from the aerial parts of Daphne linearifolia Hart. Their chemical structures were elucidated by extensive NMR spectral studies, as well as by ESI-MS analysis. The affinity of all compounds towards Hsp90, one of the most promising targets for the modern anti-cancer therapy, by surface plasmon resonance was tested. Achieved results demonstrated that 1 efficiently interacts with the protein, also allowing some structure–activity relationship evaluations.     

Clusterin activates survival through the phosphatidylinositol 3-kinase/Akt pathway

Clusterin is, in its major form, a secreted heterodimeric disulfide-linked glycoprotein (75-80 kDa). It was first linked to cell death in the rat ventral prostate after androgen deprivation. Recent studies have demonstrated that overexpression of clusterin in prostatic cells protects them against tumor necrosis factor-alpha (TNFalpha)-induced apoptosis. However the details of this survival mechanism remain undefined. Here, we investigate how clusterin prevents cells from undergoing TNFalpha-induced apoptosis. We established a double-stable prostatic cell line for inducible clusterin by using the Tet-On gene expression system. We demonstrated that 50% of the cells overexpressing clusterin escaped from TNFalpha- and actinomycin D-induced cell death. Moreover we demonstrated that the incubation of MLL cells with conditioned medium containing the secreted clusterin or the supplementation of purified clusterin in the extracellular medium decreased the TNFalpha-induced apoptosis significantly. This extracellular action implicates megalin, the putative membrane receptor for clusterin to mediate survival. Indeed clusterin overexpression up-regulated the expression of megalin and induced its phosphorylation in a dose-dependent manner. We interestingly showed that clusterin overexpression is associated with the up-regulation of the phosphorylation of Akt. Activated Akt induced the phosphorylation of Bad and caused a decrease of cytochrome c release. These results enable us to pinpoint one mechanism by which secreted clusterin favors survival in androgen-independent prostate cancer cells, implicating its receptor megalin and Akt survival pathway.     

Coexistence of predominantly nonculturable rhizobia with diverse, endophytic bacterial taxa within nodules of wild legumes

A previous analysis showed that Gammaproteobacteria could be the sole recoverable bacteria from surface-sterilized nodules of three wild species of Hedysarum. In this study we extended the analysis to eight Mediterranean native, uninoculated legumes never previously investigated regarding their root-nodule microsymbionts. The structural organization of the nodules was studied by light and electron microscopy, and their bacterial occupants were assessed by combined cultural and molecular approaches. On examination of 100 field-collected nodules, culturable isolates of rhizobia were hardly ever found, whereas over 24 other bacterial taxa were isolated from nodules. None of these nonrhizobial isolates could nodulate the original host when reinoculated in gnotobiotic culture. Despite the inability to culture rhizobial endosymbionts from within the nodules using standard culture media, a direct 16S rRNA gene PCR analysis revealed that most of these nodules contained rhizobia as the predominant population. The presence of nodular endophytes colocalized with rhizobia was verified by immunofluorescence microscopy of nodule sections using an Enterobacter-specific antibody. Hypotheses to explain the nonculturability of rhizobia are presented, and pertinent literature on legume endophytes is discussed.     

Antioxidative response to cadmium in roots and leaves of tomato plants

Treatment of tomato seedlings (Lycopersicon esculentum Mill. cv. 63/5 F1) with increasing CdCl₂ concentrations in the culture medium resulted in Cd accumulation more important in roots than in leaves. Biomass production was severely inhibited, even at low Cd concentration. Cd reduced chlorophyll content in leaves and enhanced lipid peroxidation. An increase in antioxidative enzyme (superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, glutathione reductase) activities was more pronounced in leaves than in roots, while catalase activity increased only in roots. In addition, changes in isoenzyme composition were observed using the non-denaturing polyacrylamid gel electrophoresis.     

Co-composting of oil exhausted olive-cake, poultry manure and industrial residues of agro-food activity for soil amendment

The co-composting of exhausted olive-cake with poultry manure and sesame shells was investigated. These organic solid wastes were watered by the confectionary wastewater which is characterized by its high content of residual sugars raising its COD. Four aerated windrows were performed to establish the effects of confectionary by-products on the compost process. Different mixtures of the agro-industrial wastes were used. During the composting process, physico-chemical parameters (temperature, moisture, pH, electrical conductivity, total carbon and total nitrogen) were studied. The stability of the biological system was noticed after 70 days. The final products were characterized by their relatively high organic matter content, and low C/N ratio of 14-17. The humidification of the windrows with the wastewater seemed to have accelerated the composting process in comparison to a windrow humidified with water. In addition, the organic matter degradation was enhanced to reach 55-70%. The application of the obtained composts to soil appeared to significantly improve the soil fertility. Indeed, field experiments showed an increase in potato yield; the production was 30.5-37.5 tons ha(-1), compared to 30.5 tons ha(-1) with farm manure.     

Maturity assessment of composted olive mill wastes using UV spectra and humification parameters

In this study, two olive mill wastes - exhausted olive cake (EOC) and paste of olive mill wastewater naturally dehydrated (POMW) - were co-composted and mixed with 25% sesame bark (SB). The humification process was evidenced by quantifying the humic substances and the generally accepted humification indices: (i) the ratio of humic acid (HA) carbon to fulvic acid (FA) carbon (CHA/CFA), (ii) the ratio of water soluble organic carbon (CW) to total organic nitrogen (Cw/Norg), (iii) and the ratio of humic acid carbon to total organic carbon CHA/Corg and by determining the absorbance ratios: E2/E4, E2/E6 and E4/E6. The results showed that the time required to reach maturity was dependant on the chemical properties of the initial raw materials used. The compost including EOC had more nitrogen and synthesised more polymerised HA, the POMW compost also had acceptable degrees of stability and maturity at the end of the process. Maturation was confirmed by a decline in Cw below 1.7, an increase in nitrogen, in HA, in CHA/CFA and an elimination of phytotoxicity. Composts produced with olive mill wastes, experimented on potato culture in the field, can be considered beneficial to soils because of their humification indexes and no toxicity.     

Effect of Environmental Conditions on Hydrophobicity of Marine Bacteria Adapted to Textile Effluent Treatment

Summary Bioflocculation of bacteria isolated from the marine biomass acclimatized to textile wastewater has been achieved. Pseudomonas was the main genus found in the marine biomass. This bacterium showed an important hydrophobicity but slightly weaker than that of pilot plant genera adapted to the conventional sewage. This hydrophobicity provided the bacteria with hydrophobic characters, especially those of the polymeric extracellular substances (ECS) released in the sewage. Whereas some factors such as the divalent cations, calcium and magnesium had an effect on this bacterial hydrophobicity, glucose concentration did not have any impact. Furthermore, the physiological state of the cells hatched in the sewage had an impact on the hydrophobicity. Indeed, during the logarithmic growth phase, cell hydrophobicity increase enhanced floc formation, thus improving wastewater treatment.     

Some properties of levansucrase of Bacillus natto stabilized with periodate oxidized yeast glucomannan

It was observed that levansucrase from Bacillus natto became unstable and was easily inactivated when the salts were removed from the enzyme solution, while the enzyme was stable for long time in a buffered saline. After modification with periodate oxidized yeast glucomannan, the enzyme increased thermal stability up to 45°C, in which it conserved more than 90% of its activity after 15 min treatement. The optimum temperature was also shifted from 40°C in the case of original enzyme to 50°C for the modified enzyme after 10 min reaction time. The half-life time increased significantly from 9 min to 55 min at 50°C, however it increased from 30 min and 22 min respectively at 40°C and 45°C to more than 1 h at the same temperature. The content of carbohydrates of modified enzyme was 25% that increases the molecular weight from 57 KDa to 80 KDa. The products from sucrose by the modified enzyme were the same as the case using original enzyme. Namely, the products confirmed were levan and 3 kestoses (6-, 1-, and neo-kestose).