Designing disordered materials using DNA-coated colloids of bacteriophage fd and gold.

DNA has emerged as an exciting binding agent for programmable colloidal self-assembly. Its popularity derives from its unique properties: it provides highly specific short-ranged interactions and at the same time it acts as a steric stabilizer against non-specific van der Waals and Coulomb interactions. Because complementary DNA strands are linked only via hydrogen bonds, DNA-mediated binding is thermally reversible: it provides an effective attraction that can be switched off by raising the temperature only by a few degrees. In this article we introduce a new binary system made of DNA-functionalized filamentous fd viruses of ∼880 nm length with an aspect ratio of ∼100, and 50 nm gold nanoparticles (gold NPs) coated with the complementary DNA strands. When quenching mixtures below the melt temperature Tm, at which the attraction is switched on, we observe aggregation. Conversely, above Tm the system melts into a homogenous particulate 'gas'. We present the aggregation behavior of three different gold NP to virus ratios and compare them to a gel made solely of gold NPs. In particular, we have investigated the aggregate structures as a function of cooling rate and determine how they evolve as function of time for given quench depths, employing fluorescence microscopy. Structural information was extracted in the form of an effective structure factor and chord length distributions. Rapid cooling rates lead to open aggregates, while slower controlled cooling rates closer to equilibrium DNA hybridization lead to more fine-stranded gels. Despite the different structures we find that for both cooling rates the quench into the two-phase region leads to initial spinodal decomposition, which becomes arrested. Surprisingly, although the fine-stranded gel is disordered, the overall structure and the corresponding length scale distributions in the system are remarkably reproducible. Such highly porous systems can be developed into new functional materials.This work would not have been possible without the financial support of various agencies: EE, CPG and ZR thank the Winton Program for the Physics of Sustainability. CPG and ZR acknowledge support from the EU ERC FP7 programme via an advanced fellowship for CPG. RU and SHN received support from the Engineering and Physical Sciences Research Council (EPSRC) for financial support. Work in the GPCS Lab is funded by the BBSRC, UK. DJ acknowledges the financial support from Udayan Care, NTCU and Schlumberger Foundation's FFTF program.This is the author accepted manuscript. The final version is available from the Royal Society of Chemistry via http://dx.doi.org/10.1039/C5FD00120

In Vivo Delta Opioid Receptor Internalization Controls Behavioral Effects of Agonists

GPCRs regulate a remarkable diversity of biological functions, and are thus often targeted for drug therapies. Stimulation of a GPCR by an extracellular ligand triggers receptor signaling via G proteins, and this process is highly regulated. Receptor activation is typically accompanied by desensitization of receptor signaling, a complex feedback regulatory process of which receptor internalization is postulated as a key event. The in vivo significance of GPCR internalization is poorly understood. In fact, the majority of studies have been performed in transfected cell systems, which do not adequately model physiological environments and the complexity of integrated responses observed in the whole animal.In this study, we used knock-in mice expressing functional fluorescent delta opioid receptors (DOR-eGFP) in place of the native receptor to correlate receptor localization in neurons with behavioral responses. We analyzed the pain-relieving effects of two delta receptor agonists with similar signaling potencies and efficacies, but distinct internalizing properties. An initial treatment with the high (SNC80) or low (AR-M100390) internalizing agonist equally reduced CFA-induced inflammatory pain. However, subsequent drug treatment produced highly distinct responses. Animals initially treated with SNC80 showed no analgesic response to a second dose of either delta receptor agonist. Concomitant receptor internalization and G-protein uncoupling were observed throughout the nervous system. This loss of function was temporary, since full DOR-eGFP receptor responses were restored 24 hours after SNC80 administration. In contrast, treatment with AR-M100390 resulted in retained analgesic response to a subsequent agonist injection, and ex vivo analysis showed that DOR-eGFP receptor remained G protein-coupled on the cell surface. Finally SNC80 but not AR-M100390 produced DOR-eGFP phosphorylation, suggesting that the two agonists produce distinct active receptor conformations in vivo which likely lead to differential receptor trafficking.Together our data show that delta agonists retain full analgesic efficacy when receptors remain on the cell surface. In contrast, delta agonist-induced analgesia is abolished following receptor internalization, and complete behavioral desensitization is observed. Overall these results establish that, in the context of pain control, receptor localization fully controls receptor function in vivo. This finding has both fundamental and therapeutic implications for slow-recycling GPCRs

Hydrolyzed eggshell membrane immobilized on phosphorylcholine polymer supplies extracellular matrix environment for human dermal fibroblasts

We have found that a water-soluble alkaline-digested form of eggshell membrane (ASESM) can provide an extracellular matrix (ECM) environment for human dermal fibroblast cells (HDF) in vitro. Avian eggshell membrane (ESM) has a fibrous-meshwork structure and has long been utilized as a Chinese medicine for recovery from burn injuries and wounds in Asian countries. Therefore, ESM is expected to provide an excellent natural material for biomedical use. However, such applications have been hampered by the insolubility of ESM proteins. We have used a recently developed artificial cell membrane biointerface, 2-methacryloyloxyethyl phosphorylcholine polymer (PMBN) to immobilize ASESM proteins. The surface shows a fibrous structure under the atomic force microscope, and adhesion of HDF to ASESM is ASESM-dose-dependent. Quantitative mRNA analysis has revealed that the expression of type III collagen, matrix metalloproteinase-2, and decorin mRNAs is more than two-fold higher when HDF come into contact with a lower dose ASESM proteins immobilized on PMBN surface. A particle-exclusion assay with fixed erythrocytes has visualized secreted water-binding molecules around the cells. Thus, HDF seems to possess an ECM environment on the newly designed PMBN-ASESM surface, and future applications of the ASESM-PMBN system for biomedical use should be of great interest

DNA Encoding an HIV-1 Gag/Human Lysosome-Associated Membrane Protein-1 Chimera Elicits a Broad Cellular and Humoral Immune Response in Rhesus Macaques

Previous studies of HIV-1 p55Gag immunization of mice have demonstrated the usefulness of targeting antigens to the cellular compartment containing the major histocompatibility complex type II (MHC II) complex molecules by use of a DNA antigen formulation encoding Gag as a chimera with the mouse lysosome-associated membrane protein (mLAMP/gag). In the present study, we have analyzed the magnitude and breadth of Gag-specific T-lymphocyte and antibody responses elicited in Rhesus macaques after immunization with DNA encoding a human LAMP/gag (hLAMP/gag) chimera. ELISPOT analyses indicated that the average Gag-specific IFN-γ response elicited by the hLAMP/gag chimera was detectable after only two or three naked DNA immunizations in all five immunized macaques and reached an average of 1000 spot-forming cells (SFC)/10(6) PBMCs. High IFN-γ ELISPOT responses were detected in CD8(+)-depleted cells, indicating that CD4(+) T-cells play a major role in these responses. The T-cell responses of four of the macaques were also tested by use of ELISPOT to 12 overlapping 15-amino acids (aa) peptide pools containing ten peptides each, encompassing the complete Gag protein sequence. The two Mamu 08 immunized macaques responded to eight and twelve of the pools, the Mamu B01 to six, and the other macaque to five pools indicating that the hLAMP/gag DNA antigen formulation elicits a broad T-cell response against Gag. Additionally, there was a strong HIV-1-specific IgG response. The IgG antibody titers increased after each DNA injection, indicating a strong amnestic B-cell response, and were highly elevated in all the macaques after three immunizations. Moreover, the serum of each macaque recognized 13 of the 49 peptides of a 20-aa peptide library covering the complete Gag amino acid sequence. In addition, HIV-1-specific IgA antibodies were present in the plasma and external secretions, including nasal washes. These data support the findings of increased immunogenicity of genetic vaccines encoded as LAMP chimeras, including the response to DNA vaccines by non-human primates

Neurocranium versus Face: A Morphometric Approach with Classical Anthropometric Variables for Characterizing Patterns of Cranial Integration in Extant Hominoids and Extinct Hominins

The relative importance of the two main cranial complexes, the neurocranium and the splanchnocranium, has been examined in the five species of extant hominoids and in a huge sample of extinct hominins using six standard craniometric variables that measure the length, width and height of each cranial module. Factor analysis and two-block partial least squares were used for establishing the major patterns of developmental and evolutionary integration between both cranial modules. The results obtained show that all extant hominoids (including the anatomically modern humans) share a conserved pattern of developmental integration, a result that agrees with previous studies. The pattern of evolutionary integration between both cranial modules in australopiths runs in parallel to developmental integration. In contrast, the pattern of evolutionary and developmental integration of the species of the genus Homo is the opposite, which is probably the consequence of distinctive selective regimes for both hominin groups.JAPC, JMJA and PP received fundings from Ministerio de Ciencia e Innovación, Gobierno de España (http://www.idi.mineco.gob.es), project CGL2011-30334, and Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía, España (http://www.juntadeandalucia.es/organismo​s/economiainnovacioncienciayempleo.html), project P11-HUM-7248 and Research Groups RNM-146 and HUM-607

Are oral health conditions associated with schoolchildren's performance and school attendance in the Kingdom of Bahrain? A life-course perspective

Background The link between oral diseases and school performance and school attendance remains unclear among Middle Eastern children. Aim To investigate the relationship of oral conditions with schoolchildren’s school performance and attendance using the life course approach. Design A cross-sectional study was conducted with 466 schoolchildren aged 7-8 years from Kingdom of Bahrain (KoB) and their parents. Questionnaire data on children’s current and at birth environmental characteristics were completed by their parents. Children’s oral health measures, including ICDAS (International Caries Detection and Assessment System), PUFA (Pulp, Ulcer, Fistula, Abscess), and DDE (Developmental Defects of Enamel) indices, were the exposure variables. School performance and school attendance data obtained from the school register were the outcome variables. The data were analysed using multivariate ordinal logistic regression. Results The odds of Excellent school performance were significantly lower for children with untreated dentine caries (OR = 0.98 CI 95%: 0.96-0.99). Children with caries-treated teeth showed greater odds of Excellent school performance (OR=1.41 CI 95%: 1.15-1.74). A permissive parental style was associated with poor school attendance (OR= 2.63 CI 95%: 1.08-6.42). Conclusion Dental caries was associated with poor school performance but not with school attendance. Treated caries was associated with good school performance