Tuning the Solution Self-Assembly of a Peptide-PEG (Polyethylene Glycol) Conjugate with α-Cyclodextrin.

Cyclodextrins are saccharide ring molecules which act as host cavities that can encapsulate small guest molecules or thread polymer chains. We investigate the influence of alpha-cyclodextrin (αCD) on the aqueous solution self-assembly of a peptide-polymer conjugate YYKLVFF-PEG3K previously studied by our group [Castelletto et al., Polym. Chem., 2010, 1, 453-459]. This conjugate comprises a designed amyloid-forming peptide YYKLVFF that contains the KLVFF sequence from Amyloid ß peptide, Aß16-20, along with two aromatic tyrosine residues to enhance hydrophobicity, as well as polyethylene glycol PEG with molar mass 3 kg mol-1 . The conjugate self-assembles into ß-sheet fibrils in aqueous solution. Here we show that complexation with αCD instead generates free-floating nanosheets in aqueous solution (with a ß-sheet structure). The nanosheets comprise a bilayer with a hydrophobic peptide core and highly swollen PEG outer layers. The transition from fibrils to nanosheets is driven by an increase in the number of αCD molecules threaded on the PEG chains, as determined by 1 H NMR spectroscopy. These findings point to the use of cyclodextrin additives as a powerful means to tune the solution self-assembly in peptide-polymer conjugates and potentially other polymer/biomolecular hybrids.

Sensing Magnetic Field and Intermolecular Interactions in Diamagnetic Solution Using Residual Dipolar Couplings of Zephycandidine.

An unusual residual dipolar coupling of methylene protons was recorded in NMR spectra because aromatic zephycandidine has preferential orientation at the external magnetic field. The observed splitting contains contribution from the dipole-dipole D-coupling and the anisotropic component of J-coupling. Absolute values of the anisotropy of magnetic susceptibility |Δχax| are larger for protic solvents because of the hydrogen-bonding compared to aprotic solvents for which polar and dispersion forces are more important. The energy barrier for the reorientation due to hydrogen-bonding is 1.22 kJ/mol in methanol-d4, 0.85 kJ/mol in ethanol-d6 and 0.87 kJ/mol in acetic acid-d6. In dimethyl sulfoxide-d6, 1.08 kJ/mol corresponds to the interaction of solvent lone pair electrons with π-electrons of zephycandidine. This energy barrier decreases for acetone-d6 which has smaller electric dipole moment. In acetonitrile-d3, there is no energy barrier which suggests solvent ordering around the solute due to the solvent-solvent interactions. The largest absolute values of the magnetic anisotropy are observed for aromatic benezene-d6 and tolune-d8 which have their own preferential orientation and enhance the order in the solution. The magnetic anisotropy of "isolated" zephycandidine, not hindered by intermolecular interaction could be estimated from the correlation between Δχax and cohesion energy density.

Health-, medication- and dietary supplement-related behaviors and beliefs relatively unchanged during the COVID-19 pandemic lockdown.

BACKGROUND: The lockdown imposed to counter the coronavirus disease 2019 (COVID-19) pandemic has evoked an unprecedented phenomenon that could affect health behaviors and beliefs. OBJECTIVE: To examine how medication-, dietary supplement- and health-related behaviors, beliefs and other psychological constructs changed in Polish online health service users during the COVID-19 pandemic lockdown. METHODS: A one-time online survey accessed through a health service website was completed before and during the pandemic lockdown by separate samples of respondents. The survey examined beliefs about medicines and dietary supplements, consumption of dietary supplements, trust and contact with their advertisements, sources of dietary supplement knowledge as well as perceived health, diet, physical activity and smoking, among other things. RESULTS: The study included 1560 participants. Most examined outcomes remained unchanged over COVID-19 pandemic lockdown. Beliefs that the dietary supplement quality is well controlled became significantly more pronounced during the lockdown (adjusted ratio of estimates 1.16, 95%CI 1.06-1.27, p = 0.001). Fewer people reported having contact with dietary supplement advertisements (adjusted odds ratio 0.59, 95%CI 0.43-0.83, p = 0.002). CONCLUSIONS: The results may help understand some health-related issues associated with COVID-19 pandemic lockdown and may be used to shape aspects of health-related policy.

Griseofulvin solvate solid dispersions with synergistic effect against fungal biofilms.

Fungal biofilms are invariably recalcitrant to antifungal drugs and thus can cause recurrent serious infections. The aim of this work was to prepare highly effective form of the antifungal drug griseofulvin using the chloroform solvate embedded into different polymeric matrices. Based on their solid solubility, solvated (chloroform) and non-solvated (methanol and acetone) solid dispersions were prepared using different materials: silica, microcrystalline cellulose, polyvinylpyrrolidone and hydroxypropyl methylcellulose acetate succinate (HPMCAS) by which HPMCAS dispersions showed the highest solubility of about 200 µg/mL compared with ∼30 µg/mL for pure griseofulvin. The anti fungal potential of griseofulvin was assessed against the dermatophytes T. rubrum. Metabolic and protease activity of T. rubrum NCPF 935 with and without the presence of GF:HPMCAS chloroform solvates showed significant reduction compared to the untreated control after 24 h period. Confocal laser scanning microscopy showed thin hyphae compared to Control and GF:HPMCAS (non solvated). Dynamic vapour sorption data showed that HPMCAS formed most stable solvate structure preventing recrystallization and solvate expulsion, which could explain the disruptive effect of the biofilms. This could be explained by the formed hydrogen bonds as revealed by the solid and liquid state NMR data, which was further confirmed via thermal and FTIR analyses.

Knowledge about dietary supplements and trust in advertising them: Development and validation of the questionnaires and preliminary results of the association between the constructs.

BACKGROUND: Despite offering little overall benefit and emerging concerns about their safety, dietary supplements have become increasingly popular. Trust in advertising them may contribute to high confidence in dietary supplements in public opinion. AIM: To develop and validate a screening questionnaire intended for the general public regarding knowledge about dietary supplements and a questionnaire on trust in advertising dietary supplements, and to identify the association between these constructs. MATERIALS AND METHODS: The development and validation of the measures was overseen by the panels of experts. The conceptual frameworks of the constructs were scientifically well grounded. A set of semi-structured interviews and anonymous web-based surveys was performed. The final questionnaire was applied to 220 non-medically educated people and 121 medically educated people. RESULTS: A 17-item questionnaire on knowledge about dietary supplements and eight-item questionnaire on trust in advertising dietary supplements were developed. The measures presented satisfactory proof of validity, however, the psychometric properties of the questionnaire on knowledge were modest. Both the knowledge about dietary supplements in the study group and trust in advertising them were low. A significant negative relationship was found between knowledge about dietary supplements and trust in advertising them among the general public (Pearson's r = -0.42, 95%CI: -0.52 to -0.30, p<0.0001). This association was especially pronounced in people who reported not taking dietary supplements (Pearson's r = -0.61, 95%CI: -0.76 to -0.39, p<0.0001). CONCLUSIONS: The extensive advertising of dietary supplements appears to be in conflict with promoting evidence-based knowledge about them, which raises substantial concerns for the public health. The results of the study are only preliminary and require further confirmation and exploration.

Melanin production by tyrosinase activity on a tyrosine-rich peptide fragment and pH-dependent self-assembly of its lipidated analogue.

We investigate the self-assembly of a palmitoylated (C16-chain at the N terminus) peptide fragment in comparison to the unlipidated peptide EELNRYY, a fragment of the gut hormone peptide PYY3-36. The lipopeptide C16-EELNRYY shows remarkable pH-dependent self-assembly above measured critical aggregation concentrations, forming fibrils at pH 7, but micelles at pH 10. The parent peptide does not show self-assembly behaviour. The lipopeptide forms hydrogels at sufficiently high concentration at pH 7, the dynamic mechanical properties of which were measured. We also show that the tyrosine functionality at the C terminus of EELNRYY can be used to enzymatically produce the pigment melanin. The enzyme tyrosinase oxidises tyrosine into 3,4-dihydroxyphenylalanine (DOPA), DOPA-quinone and further products, eventually forming eumelanin. This is a mechanism of photo-protection in the skin, for this reason controlling tyrosinase activity is a major target for skin care applications and EELNRYY has potential to be developed for such uses.

Carbon-13 Cross-Polarization Magic-Angle Spinning Nuclear Magnetic Resonance for Measuring Proanthocyanidin Content and Procyanidin to Prodelphinidin Ratio in Sainfoin ( Onobrychis viciifolia) Tissues.

A procedure based on 13C CPMAS NMR was developed to study procyanidins (PCs) and prodelphinidins (PDs) directly in milled sainfoin plant tissues. Blackcurrant and Tilia samples enabled reference spectra of purified proanthocyanidin (PA) fractions, crude extracts, and milled plant tissues, with characteristic resonances at 155, 144, and 132 ppm. PC/PD ratios were estimated from the I132/I155 intensity ratio and differed by 2.5 to 5.9% compared to thiolysis data. Normalization to the 155 ppm signal intensity from reference spectra enabled analysis of PA contents with an error of ca. 8 g PAs/100 g plant tissue. The procedure estimates the lignin contribution and allows for a correction of the PA content. In six sainfoin accessions, estimated PA contents were 1.6- to 20.8-fold higher than the thiolysis and 1.4- to 2.6-fold higher than the HCl-butanol-acetone results. Method differences may reflect the presence of unextractable, possibly high molecular weight PAs in sainfoin.

Systematic Investigation of FLOWERING LOCUS T-Like Poaceae Gene Families Identifies the Short-Day Expressed Flowering Pathway Gene, TaFT3 in Wheat (Triticum aestivum L.).

To date, a small number of major flowering time loci have been identified in the related Triticeae crops, bread wheat (Triticum aestivum), durum wheat (T. durum), and barley (Hordeum vulgare). Natural genetic variants at these loci result in major phenotypic changes which have adapted crops to the novel environments encountered during the spread of agriculture. The polyploid nature of bread and durum wheat means that major flowering time loci in which recessive alleles confer adaptive advantage in related diploid species have not been readily identified. One such example is the PPD-H2 flowering time locus encoded by FLOWERING LOCUS T 3 (HvFT3) in the diploid crop barley, for which recessive mutant alleles confer delayed flowering under short day (SD) photoperiods. In autumn-sown barley, such alleles aid the repression of flowering over the winter, which help prevent the development of cold-sensitive floral organs until the onset of inductive long day (LD) photoperiods the following spring. While the identification of orthologous loci in wheat could provide breeders with alternative mechanisms to fine tune flowering time, systematic identification of wheat orthologs of HvFT3 has not been reported. Here, we characterize the FT gene families in six Poaceae species, identifying novel members in all taxa investigated, as well as FT3 homoeologs from the A, B and D genomes of hexaploid (TaFT3) and tetraploid wheat. Sequence analysis shows TaFT3 homoeologs display high similarity to the HvFT3 coding region (95-96%) and predicted protein (96-97%), with conservation of intron/exon structure across the five cereal species investigated. Genetic mapping and comparative analyses in hexaploid and tetraploid wheat find TaFT3 homoeologs map to the long arms of the group 1 chromosomes, collinear to HvFT3 in barley and FT3 orthologs in rice, foxtail millet and brachypodium. Genome-specific expression analyses show FT3 homoeologs in tetraploid and hexaploid wheat are upregulated under SD photoperiods, but not under LDs, analogous to the expression of HvFT3. Collectively, these results indicate that functional wheat orthologs of HvFT3 have been identified. The molecular resources generated here provide the foundation for engineering a novel major flowering time locus in wheat using forward or reverse genetics approaches.

Side chain variations radically alter the diffusion of poly(2-alkyl-2-oxazoline) functionalised nanoparticles through a mucosal barrier.

Functionalised nanomaterials are gaining popularity for use as drug delivery vehicles and, in particular, mucus penetrating nanoparticles may improve drug bioavailability via the oral route. To date, few polymers have been investigated for their muco-penetration, and the effects of systematic structural changes to polymer architectures on the penetration and diffusion of functionalised nanomaterials through mucosal tissue have not been reported. We investigated the influence of poly(2-oxazoline) alkyl side chain length on nanoparticle diffusion; poly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline), and poly(2-n-propyl-2-oxazoline) were grafted onto the surface of thiolated silica nanoparticles and characterised by FT-IR, Raman and NMR spectroscopy, thermogravimetric analysis, and small angle neutron scattering. Diffusion coefficients were determined in water and in a mucin dispersion (using Nanoparticle Tracking Analysis), and penetration through a mucosal barrier was assessed using an ex vivo fluorescence technique. The addition of a single methylene group in the side chain significantly altered the penetration and diffusion of the materials in both mucin dispersions and mucosal tissue. Nanoparticles functionalised with poly(2-methyl-2-oxazoline) were significantly more diffusive than particles with poly(2-ethyl-2-oxazoline) while particles with poly(2-n-propyl-2-oxazoline) showed no significant increase compared to the unfunctionalised particles. These data show that variations in the polymer structure can radically alter their diffusive properties with clear implications for the future design of mucus penetrating systems.

Self-Assembly of the Toll-Like Receptor Agonist Macrophage-Activating Lipopeptide MALP-2 and of Its Constituent Peptide.

The self-assembly of the macrophage-activating lipopeptide MALP-2 in aqueous solution has been investigated and is compared to that of the constituent peptide GNNDESNISFKEK. MALP-2 is a toll-like receptor agonist lipopeptide with diverse potential biomedical applications and its self-assembly has not previously been examined. It is found to self-assemble, above a critical aggregation concentration (cac), into remarkable "fibre raft" structures, based on lateral aggregation of ß-sheet based bilayer tapes. Peptide GNNDESNISFKEK also forms ß-sheet structures above a cac, although the morphology is distinct, comprising highly extended and twisted tape structures. A detailed insight into the molecular packing within the MALP-2 raft and GNNDESNISFKEK nanotape structures is obtained through X-ray diffraction and small-angle X-ray scattering. These results point to the significant influence of the attached lipid chains on the self-assembly motif, which lead to the raft structure for the lipopeptide assemblies.

Correction: Self-assembly of the anti-fungal polyene amphotericin B into giant helically-twisted nanotapes.

Correction for 'Self-assembly of the anti-fungal polyene amphotericin B into giant helically-twisted nanotapes' by Ian William Hamley et al., Chem. Commun., 2015, 51, 17680-17683.

Self-assembly of the anti-fungal polyene amphotericin B into giant helically-twisted nanotapes.

The amphiphilic polyene amphotericin B, a powerful treatment for systemic fungal infections, is shown to exhibit a critical aggregation concentration, and to form giant helically-twisted nanostructures via self-assembly in basic aqueous solution.

Fine-Mapping the Wheat Snn1 Locus Conferring Sensitivity to the Parastagonospora nodorum Necrotrophic Effector SnTox1 Using an Eight Founder Multiparent Advanced Generation Inter-Cross Population.

The necrotrophic fungus Parastagonospora nodorum is an important pathogen of one of the world's most economically important cereal crops, wheat (Triticum aestivum L.). P. nodorum produces necrotrophic protein effectors that mediate host cell death, providing nutrients for continuation of the infection process. The recent discovery of pathogen effectors has revolutionized disease resistance breeding for necrotrophic diseases in crop species, allowing often complex genetic resistance mechanisms to be broken down into constituent parts. To date, three effectors have been identified in P. nodorum. Here we use the effector, SnTox1, to screen 642 progeny from an eight-parent multiparent advanced generation inter-cross (i.e., MAGIC) population, genotyped with a 90,000-feature single-nucleotide polymorphism array. The MAGIC founders showed a range of sensitivity to SnTox1, with transgressive segregation evident in the progeny. SnTox1 sensitivity showed high heritability, with quantitative trait locus analyses fine-mapping the Snn1 locus to the short arm of chromosome 1B. In addition, a previously undescribed SnTox1 sensitivity locus was identified on the long arm of chromosome 5A, termed here QSnn.niab-5A.1. The peak single-nucleotide polymorphism for the Snn1 locus was converted to the KASP genotyping platform, providing breeders and researchers a simple and cheap diagnostic marker for allelic state at Snn1.

A personalized method for estimating centre of mass location of the whole body based on differentiation of tissues of a multi-divided trunk.

There are several methods for obtaining location of the centre of mass of the whole body. They are based on cadaver data, using volume and density of body parts, using radiation and image techniques. Some researchers treated the trunk as a one part only, while others divided the trunk into few parts. In addition some researchers divided the trunk with planes perpendicular to the longitudinal trunk's axis, although the best approach is to obtain trunk parts as anatomical and functional elements. This procedure was used by Dempster and Erdmann. The latter elaborated personalized estimating of inertial quantities of the trunk, while Clauser et al. gave similar approach for extremities. The aim of the investigation was to merge both indirect methods in order to obtain accurate location of the centre of mass of the whole body. As a reference location a direct method based on reaction board procedure, i.e. with a body lying on a board supported on a scale was used. The location of the centre of mass using Clauser's and Erdmann's method appeared almost identical with the location obtained with a direct method. This approach can be used for several situations, especially for people of different morphology, for the bent trunk, and for asymmetrical movements.

Correlating particle deformation with water concentration profiles during latex film formation: reasons that softer latex films take longer to dry.

During the past two decades, an improved understanding of the operative particle deformation mechanisms during latex film formation has been gained. For a particular colloidal dispersion, the Routh-Russel deformation maps predict the dominant mechanism for particle deformation under a particular set of conditions (evaporation rate, temperature, and initial film thickness). Although qualitative tests of the Routh-Russel model have been reported previously, a systematic study of the relationship between the film-formation conditions and the resulting water concentration profiles is lacking. Here, the water distributions during the film formation of a series of acrylic copolymer latexes with varying glass-transition temperatures, Tg (values of -22, -11, 4, and 19 °C), have been obtained using GARField nuclear magnetic resonance profiling. A significant reduction in the rate of water loss from the latex copolymer with the lowest Tg was found, which is explained by its relatively low polymer viscosity enabling the growth of a coalesced skin layer. The set of processing parameters where the drying first becomes impeded occurs at the boundary between the capillary deformation and the wet sintering regimes of the Routh-Russel model, which provides strong confirmation of the model's validity. An inverse correlation between the model's dimensionless control parameter and the dimensionless drying time is discovered, which is useful for the design of fast-drying waterborne films.

A variable temperature solid-state nuclear magnetic resonance, electron paramagnetic resonance and Raman scattering study of molecular dynamics in ferroelectric fluorides.

The local nuclear and electronic structures and molecular dynamics of the ferroelectric lattice in selected geometric fluorides (BaMgF(4), BaZnF(4), BaMg(1 - x)Mn(x)F(4) and BaMg(1 - x)Ni(x)F(4); x = 0.001 and 0.005) have been investigated. The (19)F and (25)Mg isotropic chemical shift δ(iso), (25)Mg quadrupolar coupling constants (C(q)) and asymmetry parameters (η) reflect the geometry of the coordination spheres. The zero-field splitting parameters |D| and |E| are consistent with distorted axial symmetry (low temperatures) and nearly rhombic symmetry (high temperatures) of octahedral Mn(2+) coordination. The high resolution of the nuclear magnetic resonance, electron paramagnetic resonance and phonon spectra are consistent with the highly ordered crystallographic structure. Combined multi-technique data evidence the subtle discontinuous changes in the temperature dependences of |D| and |E|, isotropic chemical shifts δ(iso) and signature parameters of Raman bands and suggest a discontinuous structural distortion of the fluoride octahedra. The temperature at which this change occurs depends on the ionic radius of the central ion of the octahedral site and is estimated to be ∼ 300 K for Zn(2+) fluorides and ∼ 240 K for Mg(2+) fluorides. This geometrical distortion modifies the lattice dynamics and originates from the rotation of the fluoride octahedra around a new direction approximately perpendicular to that related to the paraelectric-ferroelectric phase transition.

Light-generated paramagnetic intermediates in BLUF domains.

Blue-light sensitive photoreceptory BLUF domains are flavoproteins, which regulate various, mostly stress-related processes in bacteria and eukaryotes. The photoreactivity of the flavin adenine dinucleotide (FAD) cofactor in three BLUF domains from Rhodobacter sphaeroides, Synechocystis sp. PCC 6803 and Escherichia coli have been studied at low temperature using time-resolved electron paramagnetic resonance. Photoinduced flavin triplet states and radical-pair species have been detected on a microsecond time scale. Differences in the electronic structures of the FAD cofactors as reflected by altered zero-field splitting parameters of the triplet states could be correlated with changes in the amino-acid composition of the various BLUF domains' cofactor binding pockets. For the generation of the light-induced, spin-correlated radical-pair species in the BLUF domain from Synechocystis sp. PCC 6803, a tyrosine residue near the flavin's isoalloxazine moiety plays a critical role.

DNP enhanced NMR using a high-power 94 GHz microwave source: a study of the TEMPOL radical in toluene.

DNP enhanced (1)H NMR at 143 MHz in toluene is investigated using an NMR spectrometer coupled with a modified EPR spectrometer operating at 94 GHz and TEMPOL as the polarisation agent. A 100 W microwave amplifier was incorporated into the output stage of the EPR instrument so that high microwave powers could be delivered to the probe in either CW or pulsed mode. The maximum enhancement for the ring protons increases from approximately -16 for a 5 mM TEMPOL solution to approximately -50 for a 20 mM solution at a microwave power of approximately 480 mW. The temperature dependence of the enhancement, the NMR relaxation rates and the ESR spectrum of TEMPOL were also studied in an effort to obtain information on the dynamics of the system.

The role of isolated active centres in high-performance bioinspired selective oxidation catalysts.

Transition-metal complexes containing amino acids encapsulated within solid supports generate isolated active centres that function as effective selective oxidation catalysts using benign oxidants such as air and display high turnovers and selectivity in industrially significant oxidation reactions.

Fluorescent copper(II) bis(thiosemicarbazonates): synthesis, structures, electron paramagnetic resonance, radiolabeling, in vitro cytotoxicity and confocal fluorescence microscopy studies.

Copper bis(4-ethyl-3-thiosemicarbazonato) acenaphthenequinone (1) and copper bis(4-methyl-3-thiosemicarbazonato) acenaphthenequinone (2) are synthesized and characterized in solution, in the solid state, and radiolabeled. Serum-protein binding radioassays show good stability in solution and about 25 % binding to protein over 1 h, which is comparable with the hypoxia selective tracer [(64)Cu(ATSM)]. Cyclic voltammetry shows fast and reversible reduction at redox potentials similar to the values known for hypoxia-selective copper compounds. However, despite this, complex 1 does not show any hypoxic-selective uptake in HeLa cells over 1-h standard assays. Possible reasons for this are studied by using the intrinsic fluorescence of the Cu(II) complexes to determine the cellular distributions and uptake mechanism by confocal microscopy. The complexes are found to bind to the external cell membrane and disperse evenly in the cytoplasm only after a very slow cell internalization (>1 h). No significant changes in distribution are observed by fluorescence imaging under hypoxic conditions. The rate of localization in the cytoplasm contrasts with their Zn(II) analogues, which are known to have fast cell uptake (up to 20 min) and a clear localization in lysosomes and mitochondria. The cytotoxicity mechanism of 1 over 24 h against a number of adherent cell lines is seen to be by membrane disruption and is of a comparable magnitude to that of [Cu(ATSM)], as demonstrated by methyl tetrazolium (MTT) and lactate dehydrogenase (LDH) assays.