The binding of cationic surfactants by DNA

Isotherms for the binding of dodecyltrimethylammonium (DTA⁺) and tetradecyltrimethylammonium (TTA⁺) ions by DNA in aqueous solution at 30°C are reported. The binding isotherms were determined using a potentiometric technique with cationic surfactant-selective electrodes. The DNA concentrations used are 5 × 10^?4 and 10^?3 equiv./kg, Surfactant concentrations varying from 3 × 10^?6M to the critical micelle concentration. The influence of added NaCl (0.01 M) on the binding process is studied. The binding process is shown to be highly cooperative. Applying the binding theory of Schwarz and of Satake and Yang, binding constants and cooperativity parameters can be calculated. The binding constant K is found to be 1.2kT larger for TTA⁺ than for DTA⁺ in salt-free solution, and 1.4kT larger for TTA⁺ than for DTA⁺ in 0.01 M NaCl. The cooperativity parameter u is about 1.4kT larger for TTA⁺ in salt-free solution and 1.2kT larger in 0.01 M NaCl. It is concluded that the hydrophobic part of the bound surfactant is not completely immersed in the hydrophobic DNA core, but also interacts with other surfactant molecules. This situation is compared to the case of micelle formation.     

Complete mitochondrial genome of the Eurasian flying squirrel Pteromys volans (Sciuromorpha, Sciuridae) and revision of rodent phylogeny

In this study, the complete mitochondrial genome of the Eurasian flying squirrel Pteromys volans (Rodentia, Sciuromorpha, Sciuridae) was sequenced and characterized in detail. The entire mitochondrial genome of P. volans consisted of 16,513 bp and contained 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and two non-coding regions. Its gene arrangement pattern was consistent with the mammalian ground pattern. The overall base composition and AT contents were similar to those of other rodent mitochondrial genomes. The light-strand origin generally identified between tRNA ^Asn and tRNA ^Cys consisted of a secondary structure with an 11-bp stem and an 11-bp loop. The large control region was constructed of three characteristic domains, ETAS, CD, and CSB without any repeat sequences. Each domain contained ETAS1, subsequences A, B, and C, and CSB1, respectively. In order to examine phylogenetic contentious issues of the monophyly of rodents and phylogenetic relationships among five rodent suborders, here, phylogenetic analyses based on nucleotide sequence data of the 35 rodent and 3 lagomorph mitochondrial genomes were performed using the Bayesian inference and maximum likelihood method. The result strongly supported the rodent monophyly with high node confidence values (BP 100 % in ML and BPP 1.00 in BI) and also monophylies of four rodent suborders (BP 85–100 % in ML and BPP 1.00 in BI), except for Anomalumorpha in which only one species was examined here. Also, phylogenetic relationships among the five rodent suborders were suggested and discussed in detail.     

Function analysis of mesenchymal Bcor in tooth development by using RNA interference

Teeth, an excellent model for studying organogenesis, develop from a series of epithelial–mesenchymal interactions that are mediated by a complex molecular network. Bcor (BCL-6 interacting corepressor) has recently been discovered, but little is known about its function in tooth development. Mutations in BCOR affect humans with oculofaciocardiodental syndrome, which is an X-linked dominant disorder with presumed male lethality and which comprises microphthalmia, congenital cataracts, radiculomegaly, and cardiac and digital abnormalities. In this study, the Bcor expression pattern has been intensively investigated during mouse molar development. Bcor is expressed in both dental epithelium and the mesenchyme at E11.5. To understand the function of Bcor, knockdown of Bcor has been examined by using lentivirus-mediated RNA interference. Silencing of Bcor expression in dental mesenchymal cells at E14.5 causes dentinogenesis defects and retardation of tooth root development. Thus, our results suggest that Bcor expressed in the mesenchyme plays crucial roles during early tooth development. The function of Bcor expressed in the epithelium remains to be elucidated.     

Effect of Recombinant α1-Antitrypsin Fc-Fused (AAT-Fc)Protein on the Inhibition of Inflammatory Cytokine Production and Streptozotocin-Induced Diabetes

α₁-Antitrypsin (AAT) is a member of the serine proteinase inhibitor family that impedes the enzymatic activity of serine proteinases, including human neutrophil elastase, cathepsin G and neutrophil proteinase 3. Here, we expressed recombinant AAT by fusing the intact AAT gene to the constant region of IgG1 to generate soluble recombinant AAT-Fc protein. The recombinant AAT-Fc protein was produced in Chinese hamster ovary (CHO) cells and purified using mini-protein A affinity chromatography. Recombinant AAT-Fc protein was tested for antiinflammatory function and AAT-Fc sufficiently suppressed tumor necrosis factor (TNF)-α–induced interleukin (IL)-6 in human peripheral blood mononuclear cells (PBMCs) and inhibited cytokine-induced TNFα by different cytokines in mouse macrophage Raw 264.7 cells. However, AAT-Fc failed to suppress lipopolysaccharide-induced cytokine production in both PBMCs and macrophages. In addition, our data showed that AAT-Fc blocks the development of hyperglycemia in a streptozotocin-induced mouse model of diabetes. Interestingly, we also found that plasma-derived AAT specifically inhibited the enzymatic activity of elastase but that AAT-Fc had no inhibitory effect on elastase activity.     

New Ion Substitution Method to Enhance Electrochemical Reversibility of Co-Rich Layered Materials for Li-Ion Batteries

The recent development of high-energy LiCoO₂ (LCO) and progress in the material recycling technology have brought Co-based materials under the limelight, although their capacity still suffers from structural instability at highly delithiated states. Thus, in this study, a secondary doping ion substitution method is proposed to improve the electrochemical reversibility of LCO materials for Li-ion batteries. To overcome the instability of LCO at highly delithiated states, Na ions are utilized as functional dopants to exert the pillar effect at the Li sites. In addition, Fe-ion substitution (secondary dopant) is performed to provide thermodynamically stable surroundings for the Na-ion doping. Density functional theory calculations reveal that the formation energy for the Na-doped LCO is significantly reduced in the presence of Fe ions. Na and Fe doping improve the capacity retention as well as the average voltage decay at a cutoff voltage of 4.5 V. Furthermore, structural analysis indicates that the improved cycling stability results from the suppressed irreversible phase transition in the Na- and Fe-doped LCO. This paper highlights the fabrication of high-energy Co-rich materials for high voltage operations, via a novel ion substitution method, indicating a new avenue for the manufacturing of layered cathode materials with a long cycle life.     

Extraction of indole alkaloids fromCatharanthus roseus by using supercritical carbon dioxide

Summary Indole alkaloids, particularly vindoline and catharanthine, were extracted from the leaves ofCatharanthus roseus by supercritical extraction with CO₂. The contents of vindoline and catharanthine in the extracts were determined by HPLC and identified by LC/MS. About 52 %(w/w) of the initial vindoline content, 1.5 mg vindoline/g dry wt leaves, was recovered after extracting this material for 10 h with the CO₂ flow rate of 400 ml/min at 40°C and 150 bar. Vindoline concentration in the extract was 67 %(w/w).     

Transgenic cucumber fruits that produce elevated level of an anti-aging superoxide dismutase

Superoxide dismutase (SOD) plays an important role in cellular defense against oxidative stress in aerobic organisms. To generate cucumber (Cucumis sativus L.) fruits producing high yields of SOD for an anti-aging cosmetic material as a plant bioreactor, the CuZnSOD cDNA (mSOD1) from cassava was introduced into cucumber fruits by Agrobacterium-mediated transformation using the ascorbate oxidase promoter with high expression in fruits. The bialaphos-resistant shoots were selected on medium containing MS basal salts, 2 mg l^–1 BA, 0.1 mg l^–1 IAA, 300 mg l^–1 claforan, and 2 mg l^–1 bialaphos. After 6 weeks of culture on the selection medium, the shoots were transferred to MS medium containing 1 mg l^–1 IAA, 300 mg l^–1 claforan, 2 mg l^–1 bialaphos to induce roots. Southern blot analysis confirmed that the mSOD1 gene was properly integrated into the nuclear genomes of three cucumber plants tested. The mSOD1 gene was highly expressed in the transgenic cucumber fruits, whereas it was expressed at a low level in the transgenic leaves. The SOD specific activity (units/mg protein) in transgenic fruits was approximately 3 times higher than in those of non-transgenic plants.     

Neural and social correlates of attitudinal brokerage: using the complete social networks of two entire villages

To avoid polarization and maintain small-worldness in society, people who act as attitudinal brokers are critical. These people maintain social ties with people who have dissimilar and even incompatible attitudes. Based on resting-state functional magnetic resonance imaging (n = 139) and the complete social networks from two Korean villages (n = 1508), we investigated the individual-level neural capacity and social-level structural opportunity for attitudinal brokerage regarding gender role attitudes. First, using a connectome-based predictive model, we successfully identified the brain functional connectivity that predicts attitudinal diversity of respondents'' social network members. Brain regions that contributed most to the prediction included mentalizing regions known to be recruited in reading and understanding others’ belief states. This result was corroborated by leave-one-out cross-validation, fivefold cross-validation and external validation where the brain connectivity identified in one village was used to predict the attitudinal diversity in another independent village. Second, the association between functional connectivity and attitudinal diversity of social network members was contingent on a specific position in a social network, namely, the structural brokerage position where people have ties with two people who are not otherwise connected.