Effect of Polymer Crystallinity in P3HT:PCBM Solar Cells on Band Gap Trap States and Apparent Recombination Order

The non‐geminate recombination of charge carriers in polymer‐fullerene solar cells has been modeled in the last few years with a trap‐assisted recombination model, which states that the apparent recombination order depends on the concentration of trapped charges tailing into the band gap. Higher concentrations of trapped charges lead to higher apparent recombination orders. In this work, the mass fraction f of highly crystalline nanofibrillar P3HT to the total P3HT content in P3HT:PCBM solar cells is consistently varied, controlling the temperature of a nanofibers‐P3HT casting dispersion. A systematic study of the apparent recombination order, measured with a transient photovoltage technique, as a function of f is presented. A correlation is shown between the apparent recombination order, the P3HT crystallinity, and the trap concentration in the band gap measured with an admittance spectroscopy technique.     

First Records on Genetic Diversity and Population Structure of Algerian Peanut (Arachis hypogaea) Using Microsatellite Markers

Peanut (Arachis hypogaea L) is one of the wide cultivated plants with a narrow genetic base, hence the interest in prospecting, rescuing, and characterizing germplasm of this species is continuously carried out. In this work, eleven microsatellite markers were used to assess the genetic diversity and population structure of 68 Algerian peanut accessions originated from four geographic regions in the north and south of Algeria. A total of 83 alleles were amplified with a mean number of 7.545 alleles per locus and polymorphic information content (PIC) ranged from 0.625 to 0.874. The observed and expected heterozygosity varied from 0.31 to 1.00 and from 0.61 to 0.84 with a mean of 0.704 and 0.732, respectively. Genetic structure analysis showed a strong population at K?=?2, separating accessions according to their subspecies affiliation (hypogeae ssp. and fastigiata ssp.). It was also able to quantify the genetic correlations between genotypes using principal component analysis (PCA) and the method of groups of unweighted pairings with arithmetic means (UPGMA). Analysis of molecular variance (AMOVA) revealed high genetic variation within individuals (90.7%) and low genetic differentiation between subspecies (10.3%) and among populations (8.9%) from different geographical origin. Genetic diversity analysis in this study provides useful information for the exploration and utilization of these peanut cultivars.

     

Daxx is required for stress-induced cell death and JNK activation

Daxx has been implicated in the modulation of apoptosis in response to various stimuli. In the nucleus, Daxx interacts and colocalizes with the promyelocytic leukemia protein (PML) into the PML-nuclear body. Moreover, overexpressed Daxx positively modulates FAS-ligand and TGFbeta-induced apoptosis. However, recent reports indicate that Daxx can also act as an antiapoptotic factor. As most studies on the role of Daxx in cell death have been conducted using tumour cell lines, we analysed the function of Daxx in physiological settings. We found that Daxx is induced upon exposure to ultraviolet (UV) irradiation and hydrogen peroxide treatment. We employed RNA interference to downregulate Daxx in primary fibroblasts. Remarkably, Daxx-depleted cells are resistant to cell death induced by both UV irradiation and oxidative stress. Furthermore, the downregulation of Daxx results in impaired MKK/c-Jun-N-terminal kinase (JNK) activation. This is the first evidence that Daxx promotes cell death and JNK activation in physiological conditions.     

<Emphasis Type="Italic">Pseudomonas</Emphasis> spp. increases root biomass and tropane alkaloid yields in transgenic hairy roots of <Emphasis Type="Italic">Datura</Emphasis> spp.

Transgenic hairy roots of Datura spp., established using strain A4 of Agrobacterium rhizogenes, are genetically stable and produce high levels of tropane alkaloids. To increase biomass and tropane alkaloid content of this plant tissue, four Pseudomonas strains, Pseudomonas fluorescens P64, P66, C7R12, and Pseudomonas putida PP01 were assayed as biotic elicitors on transgenic hairy roots of Datura stramonium, Datura tatula, and Datura innoxia. Alkaloids were extracted from dried biomass, and hyoscyamine and scopolamine were quantified using liquid chromatography-tandem mass spectrometry analysis. D. stramonium and D. innoxia biomass production was stimulated by all Pseudomonas spp. strains after a 5-d treatment. All strains of P. fluorescens increased hyoscyamine yields compared to untreated cultures after both 5 and 10 d of treatment. Hyoscyamine yields were highest in D. tatula cultures exposed to a 5-d treatment with C7R12 (16.633 + 0.456 mg g^?1 dry weight, a 431% increase) although the highest yield increases compared to the control were observed in D. stramonium cultures exposed to strains P64 (511% increase) and C7R12 (583% increase) for 10 d. D. innoxia showed the highest scopolamine yields after elicitation with P. fluorescens strains P64 for 5 d (0.653 + 0.021 mg g^?1 dry weight, a 265% increase) and P66 for 5 and 10 d (5 d, 0.754 + 0.0.031 mg g^?1 dry weight, a 321% increase; 10 d 0.634 + 0.046 mg g^?1 dry weight, a 277% increase). These results show that the Pseudomonas strains studied here can positively and significantly affect biomass and the yields of hyoscyamine and scopolamine from transgenic roots of the three Datura species.     

Detection and molecular characterization of enteric viruses in environmental samples in Monastir,Tunisia between January 2003 and April 2007

Aims: A prospective study was performed to characterize the main human enteric viruses able to persist in sewage samples and in shellfish tissues, and to establish the correlation between environmental strains and viral infantile diarrhoea observed in the same area during the same period. Methods and Results: A total of 250 sewage (raw and treated) and 60 shellfish samples were collected between January 2003 and April 2007 in Monastir region, Tunisia. Group A rotavirus (RVA) was detected in 80 (32%) sewage samples, norovirus (NoV) in 11 (4·4%) and enteric adenovirus (AdV) in 1 (0·4%). Among 60 shellfish samples collected near sewage effluents, one was contaminated by NoV (1·6%). Conclusion: Our data represent the first documentation in Tunisia, combining gastroenteritis viruses circulating in the environment and in clinical isolates. We observed a correlation between environmental strains and those found in children suffering from gastroenteritis during the same period study. This suggests the existence of a relationship between water contamination and paediatric diarrhoea. Significance and Impact of the Study: Our results address the potential health risks associated with transmission of human enteric viruses through water‐related environmental routes. The research findings will aid in elucidating the molecular epidemiology and circulation of enteric viruses in Tunisia and in Africa, where data are rare.     

The noncoding and surface envelope coding sequences of myeloblastosis-associated virus are respectively responsible for nephroblastoma development and renal hyperplasia.

The use of chimeric viruses allowed us to establish that myeloblastosis-associated virus long terminal repeat sequences are necessary and sufficient for induction of nephroblastoma in chickens and that the blastemal hyperplasia induced by env SU is not a prerequisite for tumor development but rather constitutes a predisposing stage.     

Daxx: death or survival protein?

The death domain-associated protein (Daxx) was originally cloned as a CD95 (FAS)-interacting protein and modulator of FAS-induced cell death. Daxx accumulates in both the nucleus and the cytoplasm; in the nucleus, Daxx is found associated with the promyelocytic leukaemia (PML) nuclear body and with alpha-thalassemia/mental retardation syndrome protein (ATRX)-positive heterochromatic regions. In the cytoplasm, Daxx has been reported to interact with various proteins involved in cell death regulation. Despite a significant number of studies attempting to determine Daxx function in apoptotic and non-apoptotic cell death, its precise role in this process is only partially understood. Here, we critically review the current understanding of Daxx function and shed new light on this interesting field.     

Bacterial monitoring by molecular tools of a continuous stirred tank reactor treating textile wastewater

This study was performed to examine the effect of the bacterial diversity changes on the performances of a continuously stirred tank reactor (CSTR) treating textile wastewater. The molecular fingerprint established using polymerase chain reaction-single stranded conformation polymorphism (PCR-SSCP) methods showed that bacterial community profiles changed simultaneously with the increase of the wastewater loading rates (WLR). For the two WLR of 0.28 g l(-1)d(-1) and 0.37 g l(-1)d(-1), the reactor maintained good performances, suggesting that the large bacterial community present a high specific activity. The increase of the WLR from 0.37 to 1.12 g l(-1)d(-1) decreased the colour and the chemical oxygen demand (COD) removal efficiencies from 90% to 55% and from 85% to 30%, respectively, explained by the decrease of the bacterial diversity and activity. The changes of the bacterial dominance had no affect on the reactor performances. However, the decrease of the bacterial diversity significantly affected the colour and the COD removal efficiencies. It should conclude that indigo dye-containing textile wastewater treatment required the concerted activity of multiple bacterial populations.     

<Emphasis Type="Italic">Desulfovibrio legallis</Emphasis> sp. nov.: A Moderately Halophilic,Sulfate-Reducing Bacterium Isolated from a Wastewater Digestor in Tunisia

A new moderately halophilic sulfate-reducing bacterium (strain H₁^T) was enriched and isolated from a wastewater digestor in Tunisia. Cells were curved, motile rods (2–3 x 0.5 μm). Strain H₁^T grew at temperatures between 22 and 43°C (optimum 35°C), and at pH between 5.0 and 9.2 (optimum 7.3–7.5). Strain H₁^T required salt for growth (1–45 g of NaCl/l), with an optimum at 20–30 g/l. Sulfate, sulfite, thiosulfate, and elemental sulfur were used as terminal electron acceptors but not nitrate and nitrite. Strain H₁^T utilized lactate, pyruvate, succinate, fumarate, ethanol, and hydrogen (in the presence of acetate and CO₂) as electron donors in the presence of sulfate as electron acceptor. The main end-products from lactate oxidation were acetate with H₂ and CO₂. The G + C content of the genomic DNA was 55%. The predominant fatty acids of strain H₁^T were C_15:0 iso (38.8%), C_16:0 (19%), and C_14:0 iso 3OH (12.2%), and menaquinone MK-6 was the major respiratory quinone. Phylogenetic analysis of the small-subunit (SSU) ribosomal RNA (rRNA) gene sequence indicated that strain H₁^T was affiliated to the genus Desulfovibrio. On the basis of SSU rRNA gene sequence comparisons and physiological characteristics, strain H₁^T is proposed to be assigned to a novel species of sulfate reducers of the genus Desulfovibrio, Desulfovibrio legallis sp. nov. (= DSM 19129^T = CCUG 54389^T).