Directed electron transfer in Langmuir-Schäfer layers of porphyrin-fullerene and phthalocyanine-fullerene dyads in inverted organic solar cells.

In this study double linked porphyrin-fullerene and phthalocyanine-fullerene dyads and a single linked phthalocyanine-fullerene dyad were studied as components in inverted organic solar cells (OSCs) equipped with the well known P3HT:PCBM bulk heterojunction as the photoactive layer. The dyad monolayers were deposited onto a surface of P3HT:PCBM by using the Langmuir-Schäfer method, therefore forming oriented monolayers in which the electron donor (D) and the acceptor (A) exist as a close proximity pair in a 1:1 molar ratio. As a result of this structure short circuit current density (J(sc)), open circuit voltage (V(oc)), and power conversion efficiency (η) increased, while the fill factor (FF) remained the same. The devices which contained dyads with double linkage produced higher efficiencies than the one with a single linked dyad. This result can be explained in terms of molecular orientation. It was also verified that the prepared OSC devices have promising long term air stability.

Hev b 6.01 and Hev b 5 induce pro-inflammatory cytokines and chemokines from peripheral blood mononuclear cells in latex allergy.

BACKGROUND: Hev b 6.01 (prohevein) and Hev b 5 [acidic natural rubber latex (NRL) protein] are major IgE-binding allergens in NRL allergy. OBJECTIVE: To examine allergen-specific cytokine and chemokine responses in NRL-allergic patients. METHODS: Fourteen NRL-allergic patients and 10 healthy controls participated in the study. Hev b 6.01 and Hev b 5 were purified under non-denaturating conditions by chromatographic methods. Specific IgE antibodies were measured by ELISA and proliferation of peripheral blood mononuclear cells (PBMC) by (3)H-thymidine incorporation assay. Allergen-specific induction of cytokine and chemokine mRNA in PBMC was measured by real-time PCR and protein levels by ELISA. Surface expression of chemokine receptors was analysed by flow cytometry. RESULTS: Twelve (86%) NRL-allergic patients had positive skin prick test reactions and IgE antibodies against Hev b 6.01, but less than 30% responded to Hev b 5. Cell proliferation against Hev b 6.01, but not against Hev b 5, was significantly increased. Both allergens elicited significantly higher expression of pro-inflammatory and T-helper type 2 cytokines (TNF, IL-12p40, IL-13) and chemokines (CCL3, CCL4, CCL20) in the NRL-allergic patients than in controls. Interestingly, mRNA expression of the regulatory cytokine TGF-beta1 was reduced, whereas IL-10 expression was enhanced after allergen stimulations in patients with NRL allergy. Finally, the NRL-allergic patients showed increased CCR4 expression on CD3(+)CD8(-) T cells and decreased CXCR3 expression on CD3(+)CD8(+) T cells. CONCLUSION: Allergen-specific induction of cytokines and chemokines in PBMC and chemokine receptor expression on circulating T cells may contribute to the pathogenesis of NRL allergy.

Characterization of the hrp pathogenicity cluster of Erwinia carotovora subsp. carotovora: high basal level expression in a mutant is associated with reduced virulence.

Extracellularly targeted proteins are crucial for virulence of gram-negative phytopathogenic bacteria. Erwinia carotovora subsp. carotovora employs the so-called type II (GSP) pathway to secrete a number of pectinases and cellulases, which cause the typical tissue maceration symptoms of soft-rot disease. The type III (hrp) pathway is the major virulence determinant in the genera Pseudomonas, Ralstonia and Xanthomonas, and in non-macerating species of Erwinia. The hrp cluster was recently partially characterized from E. carotovora sp. carotovora, and shown to affect virulence during early stages of infection. Here we have isolated and characterized 15 hrp genes comprising the remaining part of the cluster. The genes hrpL, hrpXY and hrpS were deduced to be transcribed as separate units, whereas the 11 remaining genes from hrpJ to hrcU form a single large operon. The hrpX gene, which codes for the sensory kinase of the two-component regulatory locus hrpXY was insertionally inactivated by placing a transposon (entranceposon) in the gene. The resulting mutant bacterium expresses the hrp genes at high basal level even in a non-inducing medium. This relative overexpression was shown to be due to the hrpX::entranceposon insertion causing enhanced transcription of the downstream hrpY gene. The hrpX(-)-hrpYC mutant bacterium exhibited a slower growth rate and the appearance of disease symptoms in infected Arabidopsis plants was delayed, as compared to the wild-type strain. The need for hrp gene expression for virulence has been documented in both non-macerating plant pathogens and in soft-rotting Erwinia sp. but this is the first demonstration that high basal-level expression of hrp -regulated genes may actually have a negative impact on disease progress in a susceptible host plant.