Global DNA methylation profile at LINE-1 repeats and promoter methylation of genes involved in DNA damage response and repair pathways in human peripheral blood mononuclear cells in response to γ-radiation

Molecular and Cellular Biochemistry - DNA methylation is an epigenetic mechanism, which plays an important role in gene regulation. The present study evaluated DNA methylation profile of LINE1...     

Metal ion mediated imprinting for electrochemical enantioselective sensing of L-histidine at trace level

Enantioselective trace level sensing of l-histidine (limit of detection, 1.980 ngm L(-1), S/N=3) was feasible with the use of a typical, reproducible, and rugged complex imprinted polymer-based pencil graphite electrode, in aqueous samples. In the present instance, the Cu(2+) ion-mediated imprinting of l-histidine in an molecularly imprinted polymer motif actually helped upbringing electrocatalytic activity to respond an enhanced differential pulse anodic stripping voltammetric oxidation peak of l-histidine, without any cross-reactivity and false-positive, in real samples. The proposed sensor could be considered suitable for the practical applications in biomarking histedinemia, a disease associated with L-histidine metabolic disorders, in clinical settings.     

Blue-light-mediated shade avoidance requires combined auxin and brassinosteroid action in Arabidopsis seedlings

Plant growth in dense vegetation can be strongly affected by competition for light between neighbours. These neighbours can not only be detected through phytochrome-mediated perception of a reduced red:far-red ratio, but also through altered blue light fluence rates. A reduction in blue light (low blue) induces a set of phenotypic traits, such as shoot elongation, to consolidate light capture; these are called shade avoidance responses. Here we show that both auxin and brassinosteroids (BR) play an important role in the regulation of enhanced hypocotyl elongation of Arabidopsis seedlings in response to blue light depletion. Only when both hormones are experimentally blocked simultaneously, using mutants and chemical inhibitors, will the response be fully inhibited. Upon exposure to low blue several members of the cell wall modifying XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE (XTH) protein family are regulated as well. Interestingly, auxin and BR each regulate a subset of these XTHs, by which they could regulate cell elongation. We hypothesize that auxin and BR regulate specific XTH genes in a non-redundant and non-synergistic manner during low-blue-induced shade avoidance responses of Arabidopsis seedlings, which explains why both hormones are required for an intact low-blue response.     

Next generation genome-wide association tool: design and coverage of a high-throughput European-optimized SNP array

The success of genome-wide association studies has paralleled the development of efficient genotyping technologies. We describe the development of a next-generation microarray based on the new highly-efficient Affymetrix Axiom genotyping technology that we are using to genotype individuals of European ancestry from the Kaiser Permanente Research Program on Genes, Environment and Health (RPGEH). The array contains 674,517 SNPs, and provides excellent genome-wide as well as gene-based and candidate-SNP coverage. Coverage was calculated using an approach based on imputation and cross validation. Preliminary results for the first 80,301 saliva-derived DNA samples from the RPGEH demonstrate very high quality genotypes, with sample success rates above 94% and over 98% of successful samples having SNP call rates exceeding 98%. At steady state, we have produced 462 million genotypes per week for each Axiom system. The new array provides a valuable addition to the repertoire of tools for large scale genome-wide association studies.     

The proteolipid protein promoter drives expression outside of the oligodendrocyte lineage during embryonic and early postnatal development

The proteolipid protein (Plp) gene promoter is responsible for driving expression of one of the major components of myelin--PLP and its splice variant DM-20. Both products are classically thought to express predominantly in oligodendrocytes. However, accumulating evidence suggests Plp expression is more widespread than previously thought. In an attempt to create a mouse model for inducing oligodendrocyte-specific gene deletions, we have generated transgenic mice expressing a Cre recombinase cDNA under control of the mouse Plp promoter. We demonstrate Plp promoter driven Cre expression is restricted predominantly to mature oligodendrocytes of the central nervous system (CNS) at postnatal day 28. However, crosses into the Rosa26(LacZ) and mT/mG reporter mouse lines reveal robust and widespread Cre activity in neuronal tissues at E15.5 and E10.5 that is not strictly oligodendrocyte lineage specific. By P28, all CNS tissues examined displayed high levels of reporter gene expression well outside of defined white matter zones. Importantly, our study reinforces the emerging idea that Plp promoter activity is not restricted to the myelinating cell lineage, but rather, has widespread activity both during embryonic and early postnatal development in the CNS. Specificity of the promoter to the oligodendrocyte cell lineage, as shown through the use of a tamoxifen inducible Plp-CreER(t) line, occurs only at later postnatal stages. Understanding the temporal shift in Plp driven expression is of consequence when designing experimental models to study oligodendrocyte biology.     

Insect feeding deterrent and growth inhibitory activities of scopoletin isolated from Artemisia annua against Spilarctia obliqua (Lepidoptera: Noctuidae)

Abstract Artemisia annua (Asteraceae) is well known for its antimalarial activities due to presence of the compound artemisinin. We isolated a methoxy coumarin from the stem part of A. annua and confirmed its identity as scopoletin through mass spectral data. The structure was established from ¹H‐nuclear magnetic resonance (NMR), ¹³C‐NMR. The compound scopoletin was evaluated for its feeding deterrence and growth inhibitory potential against a noxious lepidopteran insect, Spilartctia obliqua Walker. Scopoletin gave FD₅₀ (feeding deterrence of 50%) value of 96.7 μg/g diet when mixed into artificial diet. S. obliqua larvae (12‐day‐old) exposed to the highest concentration (250 μg/g diet) of scopoletin showed 77.1% feeding‐deterrence. In a growth inhibitory assay, scopoletin provided 116.9% growth inhibition at the highest dose of 250 μg/g diet with a GI₅₀ (growth inhibition of 50%) value of 20.9 μg/g diet. Statistical analysis showed a concentration‐dependent dose response relationship toward both feeding deterrent and growth inhibitory activities. Artemisinin is found mainly in the leaves of A. annua and not in the stems, which are typically discarded as waste. Therefore identification of scopoletin in stems of A. annua may be important as a source of this material for pest control.     

Early dysregulation of the mitochondrial proteome in a mouse model of Alzheimer's disease

Mitochondrial structural and functional alterations appear to play to an important role in the pathogenesis of Alzheimer's disease (AD). In the present study, we used a quantitative comparative proteomic profiling approach to analyze changes in the mitochondrial proteome in AD. A triple transgenic mouse model of AD (3xTg-AD) which harbors mutations in three human transgenes, APP(Swe), PS1(M146V) and Tau(P301L), was used in these experiments. Quantitative differences in the mitochondrial proteome between the cerebral cortices of 6-month-old male 3xTg-AD and non-transgenic mice were determined by using two-dimensional difference gel electrophoresis (2D-DIGE) and tandem mass spectrometry. We identified 23 different proteins whose expression levels differed significantly between triple transgenic and non-transgenic mitochondria. Both down-regulated and up-regulated mitochondrial proteins were observed in transgenic AD cortices. Proteins which were dysregulated in 3xTg-AD cortices functioned in a wide variety of metabolic pathways, including the citric acid cycle, oxidative phosphorylation, pyruvate metabolism, glycolysis, oxidative stress, fatty acid oxidation, ketone body metabolism, ion transport, apoptosis, and mitochondrial protein synthesis. These alterations in the mitochondrial proteome of the cerebral cortices of triple transgenic AD mice occurred before the development of significant amyloid plaque and neurofibrillary tangles, indicating that mitochondrial dysregulation is an early event in AD.