2D and Trap‐Assisted 2D Langevin Recombination in Polymer:Fullerene Blends

The impact of trapping on the recombination dynamics in polymer:fullerene blends is clarified using the highly ordered bulk heterojunction (BHJ) blend poly[2,5‐bis(3‐tetradecylthiophen‐2‐yl)thieno[3,2‐b]thiophene] (PBTTT) and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) at different weight ratios as a model system. The recombination dynamics are determined using both transient charge extraction and steady‐state techniques. The results show that both the decay of photogenerated charge and the light ideality factor at a polymer:fullerene weight ratio of 1:4 are fully consistent with 2D Langevin recombination; in the 1:1 case the recombination is seen to be affected by electron trapping. The theory of 2D Langevin recombination is extended to the case with high trap density in agreement with the observations in the 1:1 case. The recombination capture coefficients are derived both for trap‐assisted and band‐to‐band recombination and it can be seen that anisotropic charge transport reduces the capture coefficients in both cases resulting in a reduced overall recombination.     

The effect of convulsions induced by flurothyl on ribonucleic acid synthesis in rat cerebral cortex during the recovery phase.

The effect of convulsions, induced by flurothyl, on RNA synthesis in purified unfractionated nuclei and the cytoplasm of rat cerebral cortex was studied by using a double-label technique involving injection of [3H]- and [14C]-orotate intracisternally. 2. Intact RNA was extracted in 80% yield by an enzymic method by using a proteinase in the presence of sodium dodecyl sulphate followed by deoxyribonuclease. Electrophoresis on 1.5% polyacrylamide-0.5% agarose gels revealed the presence of giant nuclear RNA of size up to approx. 300X 10(6) daltons and mRNA of maximal mol.wt. 9 X 10(6)-16 X 10(6). 3. Nuclear RNA synthesis was decreased to 27% in the first 15 min after convulsions but rapidly increased, so that at 1 1/2 h it was 124% of the control, and at 6 h 147%. 4. Labelling of cytoplasmic RNA was decreased to 15% at 15 min after convulsions but had not recovered to control values by 6 h. 5. Analysis of radioactive gel patterns and the 3H/14C ratio at six time-points (15 min-6h) showed that the major effect was inhibition of the processing of heterogeneous nuclear RNA resulting in a sharp decline in the export of newly synthesized RNA from the nucleus. 6. Cytoplasmic RNA patterns indicated that specific messengers were synthesized at different times during the recovery of the cell after convulsions.     

Updating the proteome of the uncultivable hemotrophic Mycoplasma suis in experimentally infected pigs

Mycoplasma suis belongs to the hemotrophic mycoplasmas that are associated with acute and chronic anemia in a wide range of livestock and wild animals. The inability to culture M. suis in vitro has hindered its characterization at the molecular level. Since the publication of M. suis genome sequences in 2011 only one proteome study has been published. Aim of the presented study was to significantly extend the proteome coverage of M. suis strain KI_3806 during acute infection by applying three different protein extraction methods followed by 1D SDS‐PAGE and LC‐MS/MS. A total of 404 of 795 M. suis KI_3806 proteins (50.8%) were identified. Data analysis revealed the expression of 83.7% of the predicted ORFs with assigned functions but also highlights the expression of 179 of 523 (34.2%) hypothetical proteins with unknown functions. Computational analyses identified expressed membrane‐associated hypothetical proteins that might be involved in adhesion or host–pathogen interaction. Furthermore, analyses of the expressed proteins indicated the existence of a hexose‐6‐phosphate‐transporter and an ECF transporter. In conclusion, our proteome study provides a further step toward the elucidation of the unique life cycle of M. suis and the establishment of an in vitro culture. All MS data have been deposited in the ProteomeXchange with identifier PXD002294 ( http://proteomecentral.proteomexchange.org/dataset/PXD002294 ).     

Neighboring Parenchyma Cells Contribute to Arabidopsis Xylem Lignification,while Lignification of Interfascicular Fibers Is Cell Autonomous

Lignin is a critical structural component of plants, providing vascular integrity and mechanical strength. Lignin precursors (monolignols) must be exported to the extracellular matrix where random oxidative coupling produces a complex lignin polymer. The objectives of this study were twofold: to determine the timing of lignification with respect to programmed cell death and to test if nonlignifying xylary parenchyma cells can contribute to the lignification of tracheary elements and fibers. This study demonstrates that lignin deposition is not exclusively a postmortem event, but also occurs prior to programmed cell death. Radiolabeled monolignols were not detected in the cytoplasm or vacuoles of tracheary elements or neighbors. To experimentally define which cells in lignifying tissues contribute to lignification in intact plants, a microRNA against CINNAMOYL CoA-REDUCTASE1 driven by the promoter from CELLULOSE SYNTHASE7 (ProCESA7:miRNA CCR1) was used to silence monolignol biosynthesis specifically in cells developing lignified secondary cell walls. When monolignol biosynthesis in ProCESA7:miRNA CCR1 lines was silenced in the lignifying cells themselves, but not in the neighboring cells, lignin was still deposited in the xylem secondary cell walls. Surprisingly, a dramatic reduction in cell wall lignification of extraxylary fiber cells demonstrates that extraxylary fibers undergo cell autonomous lignification.     

Comparison between the effects of diallyl tetrasulfide on human retina pigment epithelial cells (ARPE-19) and HCT116 cells

Background

Diallyl mono- and polysulfanes from garlic are known to induce an adaptive cell response and the formation of antioxidants in cancer cells. In the case of a severe ER stress and a failure in the response, cancer cells eventually go into apoptosis. Only little is known about the response of normal cells upon treatment.

Methods

Normal ARPE-19 cells were treated with diallyl tetrasulfide to study their cellular response and the results were compared with those of HCT116 cancer cells. Cell viability was checked by an MTT assay and cytofluorimetry. The formation of superoxide radicals, H₂O₂ and thiols were determined and proteins involved in the ER stress response were also detected by Western blot analysis.

Results

We found that diallyl tetrasulfide induced reactive oxygen species (ROS) in normal cells similar to cancer cells in a time (0 to 60 min) and dose dependent manner (0 to 50 μM). The level of heme oxigenase-1 (HO-1) was up-regulated in both cell types. Initially, we found a decrease in the total thiol level in both cell types but in contrast to cancer cells, normal cells recovered from the decrease in the total thiol concentration within 60 min of treatment.

Conclusions

The recovery of the thiol concentration in normal cells treated with diallyl tetrasulfide seems to be responsible for the failure to induce the ER stress signalling pathway and finally apoptosis in normal cells.

General Significance

The difference in the recovery of the thiol status might be an explanation for the anti-carcinogenic effects of garlic compounds.     

Identification, replication, and fine-mapping of Loci associated with adult height in individuals of african ancestry

Adult height is a classic polygenic trait of high heritability (h ² ∼0.8). More than 180 single nucleotide polymorphisms (SNPs), identified mostly in populations of European descent, are associated with height. These variants convey modest effects and explain ∼10% of the variance in height. Discovery efforts in other populations, while limited, have revealed loci for height not previously implicated in individuals of European ancestry. Here, we performed a meta-analysis of genome-wide association (GWA) results for adult height in 20,427 individuals of African ancestry with replication in up to 16,436 African Americans. We found two novel height loci (Xp22-rs12393627, P = 3.4×10⁻¹² and 2p14-rs4315565, P = 1.2×10⁻⁸). As a group, height associations discovered in European-ancestry samples replicate in individuals of African ancestry (P = 1.7×10⁻⁴ for overall replication). Fine-mapping of the European height loci in African-ancestry individuals showed an enrichment of SNPs that are associated with expression of nearby genes when compared to the index European height SNPs (P<0.01). Our results highlight the utility of genetic studies in non-European populations to understand the etiology of complex human diseases and traits.     

Radiative forcing of natural forest disturbances

Forest disturbances are major sources of carbon dioxide to the atmosphere, and therefore impact global climate. Biogeophysical attributes, such as surface albedo (reflectivity), further control the climate‐regulating properties of forests. Using both tower‐based and remotely sensed data sets, we show that natural disturbances from wildfire, beetle outbreaks, and hurricane wind throw can significantly alter surface albedo, and the associated radiative forcing either offsets or enhances the CO₂ forcing caused by reducing ecosystem carbon sequestration over multiple years. In the examined cases, the radiative forcing from albedo change is on the same order of magnitude as the CO₂ forcing. The net radiative forcing resulting from these two factors leads to a local heating effect in a hurricane‐damaged mangrove forest in the subtropics, and a cooling effect following wildfire and mountain pine beetle attack in boreal forests with winter snow. Although natural forest disturbances currently represent less than half of gross forest cover loss, that area will probably increase in the future under climate change, making it imperative to represent these processes accurately in global climate models.     

HIV Entry and Envelope Glycoprotein-mediated Fusion

HIV entry involves binding of the trimeric viral envelope glycoprotein (Env) gp120/gp41 to cell surface receptors, which triggers conformational changes in Env that drive the membrane fusion reaction. The conformational landscape that the lipids and Env navigate en route to fusion has been examined by biophysical measurements on the microscale, whereas electron tomography, x-rays, and NMR have provided insights into the process on the nanoscale and atomic scale. However, the coupling between the lipid and protein pathways that give rise to fusion has not been resolved. Here, we discuss the known and unknown about the overall HIV Env-mediated fusion process.