Guilt, fear, stigma and knowledge gaps: ethical issues in public health communication interventions

Public health communication campaigns have been credited with helping raise awareness of risk from chronic illness and new infectious diseases and with helping promote the adoption of recommended treatment regimens. Yet many aspects of public health communication interventions have escaped the scrutiny of ethical discussions. With the transference of successful commercial marketing communication tactics to the realm of public health, consideration of ethical issues becomes an essential component in the development and application of public health strategies. Ethical issues in public health communication are explored as they relate to eight topics: 'targeting' and 'tailoring' public health messages to particular population segments; obtaining the equivalence of informed consent; the use of persuasive communication tactics; messages on responsibility and culpability; messages that apply to harm reduction; and three types of unintended adverse effects associated with public health communication activities that may label and stigmatise, expand social gaps, and promote health as a value. We suggest that an ethical analysis should be applied to each phase of the public health communication process in order to identify ethical dilemmas that may appear subtle, yet reflect important concerns regarding potential effects of public health communication interventions on individuals and society as a whole.     

REST and its corepressors mediate plasticity of neuronal gene chromatin throughout neurogenesis

Regulation of neuronal gene expression is critical to central nervous system development. Here, we show that REST regulates the transitions from pluripotent to neural stem/progenitor cell and from progenitor to mature neuron. In the transition to progenitor cell, REST is degraded to levels just sufficient to maintain neuronal gene chromatin in an inactive state that is nonetheless poised for expression. As progenitors differentiate into neurons, REST and its co-repressors dissociate from the RE1 site, triggering activation of neuronal genes. In some genes, the level of expression is adjusted further in neurons by CoREST/MeCP2 repressor complexes that remain bound to a site of methylated DNA distinct from the RE1 site. Expression profiling based on this mechanism indicates that REST defines a gene set subject to plasticity in mature neurons. Thus, a multistage repressor mechanism controls the orderly expression of genes during development while still permitting fine tuning in response to specific stimuli.     

Ultrahigh-Density Linkage Map for Cultivated Cucumber (Cucumis sativus L.) Using a Single-Nucleotide Polymorphism Genotyping Array

Genotyping arrays are tools for high-throughput genotyping, which is beneficial in constructing saturated genetic maps and therefore high-resolution mapping of complex traits. Since the report of the first cucumber genome draft, genetic maps have been constructed mainly based on simple-sequence repeats (SSRs) or on combinations of SSRs and sequence-related amplified polymorphism (SRAP). In this study, we developed the first cucumber genotyping array consisting of 32,864 single-nucleotide polymorphisms (SNPs). These markers cover the cucumber genome with a median interval of ~2 Kb and have expected genotype calls in parents/F₁ hybridizations as a training set. The training set was validated with Fluidigm technology and showed 96% concordance with the genotype calls in the parents/F₁ hybridizations. Application of the genotyping array was illustrated by constructing a 598.7 cM genetic map based on a ‘9930’ × ‘Gy14’ recombinant inbred line (RIL) population comprised of 11,156 SNPs. Marker collinearity between the genetic map and reference genomes of the two parents was estimated at R² = 0.97. We also used the array-derived genetic map to investigate chromosomal rearrangements, regional recombination rate, and specific regions with segregation distortions. Finally, 82% of the linkage-map bins were polymorphic in other cucumber variants, suggesting that the array can be applied for genotyping in other lines. The genotyping array presented here, together with the genotype calls of the parents/F₁ hybridizations as a training set, should be a powerful tool in future studies with high-throughput cucumber genotyping. An ultrahigh-density linkage map constructed by this genotyping array on RIL population may be invaluable for assembly improvement, and for mapping important cucumber QTLs.     

Rapid Kill—Novel Endodontic Sealer and Enterococcus faecalis

With growing concern over bacterial resistance, the identification of new antimicrobial means is paramount. In the oral cavity microorganisms are essential to the development of periradicular diseases and are the major causative factors associated with endodontic treatment failure. As quaternary ammonium compounds have the ability to kill a wide array of bacteria through electrostatic interactions with multiple anionic targets on the bacterial surface, it is likely that they can overcome bacterial resistance. Melding these ideas, we investigated the potency of a novel endodontic sealer in limiting Enterococcus faecalis growth. We used a polyethyleneimine scaffold to synthesize nano-sized particles, optimized for incorporation into an epoxy-based endodontic sealer. The novel endodontic sealer was tested for its antimicrobial efficacy and evaluated for biocompatibility and physical eligibility. Our results show that the novel sealer foundation affixes the nanoparticles, achieving surface bactericidal properties, but at the same time impeding nanoparticle penetration into eukaryotic cells and thereby mitigating a possible toxic effect. Moreover, adequate physical properties are maintained. The nanosized quaternary amine particles interact within minutes with bacteria, triggering cell death across wide pH values. Throughout this study we demonstrate a new antibacterial perspective for endodontic sealers; a novel antibacterial, effective and safe antimicrobial means.     

The role of pre-symbiotic auxin signaling in ectendomycorrhiza formation between the desert truffle <Emphasis Type="Italic">Terfezia boudieri</Emphasis> and <Emphasis Type="Italic">Helianthemum sessiliflorum</Emphasis>

The ectendomycorrhizal fungus Terfezia boudieri is known to secrete auxin. While some of the effects of fungal auxin on the plant root system have been described, a comprehensive understanding is still lacking. A dual culture system to study pre mycorrhizal signal exchange revealed previously unrecognized root–fungus interaction mediated by the fungal auxin. The secreted fungal auxin induced negative taproot gravitropism, attenuated taproot growth rate, and inhibited initial host development. Auxin also induced expression of Arabidopsis carriers AUX1 and PIN1, both of which are involved in the gravitropic response. Exogenous application of auxin led to a root phenotype, which fully mimicked that induced by ectomycorrhizal fungi. Co-cultivation of Arabidopsis auxin receptor mutants tir1-1, tir1-1 afb2-3, tir1-1 afb1-3 afb2-3, and tir1-1 afb2-3 afb3-4 with Terfezia confirmed that auxin induces the observed root phenotype. The finding that auxin both induces taproot deviation from the gravity axis and coordinates growth rate is new. We propose a model in which the fungal auxin induces horizontal root development, as well as the coordination of growth rates between partners, along with the known auxin effect on lateral root induction that increases the availability of accessible sites for colonization at the soil plane of fungal spore abundance. Thus, the newly observed responses described here of the root to Terfezia contribute to a successful encounter between symbionts.     

Changing the charge distribution of beta-helical-based nanostructures can provide the conditions for charge transfer

In this work we present a computational approach to the design of nanostructures made of structural motifs taken from left-handed beta-helical proteins. Previously, we suggested a structural model based on the self-assembly of motifs taken from Escherichia coli galactoside acetyltransferase (Protein Data Bank 1krr, chain A, residues 131-165, denoted krr1), which produced a very stable nanotube in molecular dynamics simulations. Here we modify this model by changing the charge distribution in the inner core of the system and testing the effect of this change on the structural arrangement of the construct. Our results demonstrate that it is possible to generate the proper conditions for charge transfer inside nanotubes based on assemblies of krr1 segment. The electronic transfer would be achieved by introducing different histidine ionization states in selected positions of the internal core of the construct, in addition to specific mutations with charged amino acids that altogether will allow the formation of coherent networks of aromatic ring stacking, salt-bridges, and hydrogen bonds.     

Biohybrid Polymer-Antimicrobial Peptide Medium against Enterococcus faecalis

Antimicrobial peptides (AMPs) are conserved evolutionary components of the innate immune system that are being tested as alternatives to antibiotics. Slow release of AMPs using biodegradable polymers can be advantageous in maintaining high peptide levels for topical treatment, especially in the oral environment in which dosage retention is challenged by drug dilution with saliva flow and by drug inactivation by salivary enzymatic activity. Enterococcus faecalis is a multidrug resistant nosocomial pathogen and a persistent pathogen in root canal infections. In this study, four ultra-short lipopeptides (C16-KGGK, C16-KLLK, C16-KAAK and C16-KKK) and an amphipathic α-helical antimicrobial peptide (Amp-1D) were tested against E. faecalis. The antibacterial effect was determined against planktonic bacteria and bacteria grown in biofilm. Of the five tested AMPs, C16-KGGK was the most effective. Next C16-KGGK was formulated with one of two polymers poly (lactic acid co castor oil) (DLLA) or ricinoleic acid-based poly (ester-anhydride) P(SA-RA). Peptide-synthetic polymer conjugates, also referred to as biohybrid mediums were tested for antibacterial activity against E. faecalis grown in suspension and in biofilms. The new formulations exhibited strong and improved anti- E. faecalis activity.     

High resolution X-ray crystallographic structure of bovine heart cytochrome c and its application to the design of an electron transfer biosensor

Cytochrome c is one of the most studied proteins probably due to its electron-transfer properties in aerobic and anaerobic respiration. Particularly, cytochrome c from bovine heart is a small protein, M(r) 12,230 Da, globular (hydrodynamic diameter of 3.4 nm), soluble in different buffer solutions, and commercially available. Despite being a quite well-studied protein and relatively easy to manipulate from the biochemical and electrochemical viewpoint, its 3D structure has never been published. In this work, the purification, crystallization and 3D structure of one of the cytochrome c isoforms is presented to 1.5 A resolution. It is also shown how the presence of isoforms made both the purification and crystallization steps difficult. Finally, a new approach for protein electrocrystallization and design of biosensors is presented.