A few ruthenium based metal carbonyl complexes, e.g. CORM-2 and CORM-3, have therapeutic activity attributed to their ability to deliver CO to biological targets. In this work, a series of related complexes with the formula [Ru(CO)(3)Cl2L] (L = DMSO (3), L-H3CSO(CH2)(2)CH(NH2)CO2H) (6a); D,L-H3CSO(CH2)(2)CH-(NH2)CO2H (6b); 3-NC5H4(CH2)(2)SO3.Na (7); 4-NC5H4(CH2)(2)SO3Na (8); PTA (9); DAPTA (10); H3CS-(CH2)(2)CH(OH) CO2H (11); CNCMe2CO2Me (12); CNCMeEtCO2Me (13); CN(c-C3H4)CO2Et) (14)) were designed, synthesized and studied. The effects of L on their stability, CO release profile, cytotoxicity and anti-inflammatory properties are described. The stability in aqueous solution depends on the nature of L as shown using HPLC and LC-MS studies. The isocyanide derivatives are the least stable complexes, and the S-bound methionine oxide derivative is the more stable one. The complexes do not release CO gas to the headspace, but release CO2 instead. X-ray diffraction of crystals of the model protein Hen Egg White Lysozyme soaked with 6b (4UWN) and 8 (4UWV) shows the addition of Ru-II(CO)(H2O)(4) at the His15 binding site. Soakings with 7 (4UWU) produced the metallacarboxylate [Ru(COOH)(CO)(H2O)(3)](+) bound to the His15 site. The aqueous chemistry of these complexes is governed by the water-gas shift reaction initiated with the nucleophilic attack of HO- on coordinated CO. DFT calculations show this addition to be essentially barrierless. The complexes have low cytotoxicity and low hemolytic indices. Following i.v. administration of CORM-3, the in vivo bio-distribution of CO differs from that obtained with CO inhalation or with heme oxygenase stimulation. A mechanism for CO transport and delivery from these complexes is proposed.

Gum arabic (GA) is a hydrophilic composite polysaccharide derived from exudates of Acacia senegal and Acacia seyal trees. It is biocompatible, possesses emulsifying and stabilizing properties and has been explored as coating agent of nanomaterials for biomedical applications, namely magnetic nanoparticles (MNPs). Previous studies focused on the adsorption of GA onto MNPs produced by co-precipitation methods. In this work, MNPs produced by a thermal decomposition method, known to produce uniform particles with better crystalline properties, were used for the covalent coupling of GA through its free amine groups, which increases the stability of the coating layer. The MNPs were produced by thermal decomposition of Fe(acac)3 in organic solvent and, after ligand-exchange with meso-2,3-dimercaptosuccinic acid (DMSA), GA coating was achieved by the establishment of a covalent bond between DMSA and GA moieties. Clusters of several magnetic cores entrapped in a shell of GA were obtained, with good colloidal stability and promising magnetic relaxation properties (r2/r1 ratio of 350). HCT116 colorectal carcinoma cell line was used for in vitro cytotoxicity evaluation and cell-labeling efficiency studies. We show that, upon administration at the respective IC50, GA coating enhances MNP cellular uptake by 19 times compared to particles bearing only DMSA moieties. Accordingly, in vitro MR images of cells incubated with increasing concentrations of GA-coated MNP present dose-dependent contrast enhancement. The obtained results suggest that the GA magnetic nanosystem could be used as a MRI contrast agent for cell-labeling applications. Copyright © 2015 John Wiley & Sons, Ltd.

Oleic acid coated iron oxide nanoparticles synthesized by thermal decomposition in organic medium are highly monodisperse but at the same time are unsuitable for biological applications. Ligand-exchange reactions are useful to make their surface hydrophilic. However, these could alter some structural and magnetic properties of the modified particles. Here we present a comprehensive study and comparison of the effects of employing either citric acid (CA) or meso-2,3-dimercaptosuccinic acid (DMSA) ligand-exchange protocols for phase transfer of monodisperse hydrophobic iron oxide nanoparticles produced by thermal decomposition of Fe(acac)3 in benzyl ether. We show the excellent hydrodynamic size distribution and colloidal stability of the hydrophilic particles obtained by the two protocols and confirm that there is a certain degree of oxidation caused by the ligand-exchange. CA revealed to be more aggressive towards the iron oxide surface than DMSA and greatly reduced the saturation magnetization values and initial susceptibility of the resulting particles compared to the native ones. Besides being milder and more straightforward to perform, the DMSA ligand exchange protocol produces MNP chemically more versatile for further functionalization possibilities. This versatility is shown through the covalent linkage of gum Arabic onto MNP-DMSA using carboxyl and thiol based chemical routes and yielding particles with comparable properties.

The human Pin1 WW domain (hPin1_WW) is a 38 residue protein which specifically recognizes ligands rich in proline and phosphorylated in Ser and Thr residues. This work presents a protocol for the improved chemical synthesis and modification of this protein through automated microwave assisted synthesis combined with the incorporation of pseudoproline units in the protein sequence. After purification{,} the protein was characterized by Mass Spectrometry and Circular Dichroism spectroscopy with results comparable to the same WW domain chemically synthesized by other strategies or biologically expressed. The protein was further immobilized on a matrix and tested for the selective binding and mild elution of phosphorylated sequences at Ser{,} Thr and Tyr residues. These results suggest that hPin1_WW is a useful protein scaffold for the purification of phosphorylated species in pTyr and pSer{,} which can be easily produced and modified by chemical methods.

In this work, a combination of homology modeling and molecular dynamics (MD) simulations was used to investigate the factors that modulate substrate specificity and activity of the mouse AOX isoforms: mAOX1, mAOX2 (previously mAOX3l1), mAOX3 and mAOX4. The results indicate that the AOX isoform structures are highly preserved and even more conserved than the corresponding amino acid sequences. The only differences are at the protein surface and substrate-binding site region. The substrate-binding site of all isoforms consists of two regions: the active site, which is highly conserved among all isoforms, and a isoform-specific region located above. We predict that mAOX1 accepts a broader range of substrates of different shape, size and nature relative to the other isoforms. In contrast, mAOX4 appears to accept a more restricted range of substrates. Its narrow and hydrophobic binding site indicates that it only accepts small hydrophobic substrates. Although mAOX2 and mAOX3 are very similar to each other, we propose the following pairs of overlapping substrate specificities: mAOX2/mAOX4 and mAOX3/mAXO1. Based on these considerations, we propose that the catalytic activity between all isoforms should be similar but the differences observed in the binding site might influence the substrate specificity of each enzyme. These results also suggest that the presence of several AOX isoforms in mouse allows them to oxidize more efficiently a wider range of substrates. This contrasts with the same or other organisms that only express one isoform and are less efficient or incapable of oxidizing the same type of substrates.

Nucleation is a critical step determining the outcome of the entire crystallization process. Finding an effective nucleant for protein crystallization is of utmost importance for structural biology. The latter relies on good-quality crystals to solve the three-dimensional structures of macromolecules. In this study we show that crystalline barium sulfate (BaSO4) with an etched and/or ionic liquid (IL)-functionalized surface (1) can induce protein nucleation at concentrations well below the concentration needed to promote crystal growth under control conditions, (2) can shorten the nucleation time, (3) can increase the growth rate, and finally (4) may help to improve the protein crystal morphology. These effects were shown for lysozyme, RNase A, trypsin, proteinase K, myoglobin, and hemoglobin. Therefore, the use of BaSO4 particles enables us to reduce the amount of protein in crystallization trials and increases the chance of obtaining protein crystals of the desired quality. In the context of the underlying mechanism, it is shown that the protein-solid contact formation is governed by the interaction of the polar compartments of the biomacromolecule with the support. The tendency of a protein to concentrate near the solid surface is enhanced by both the hydrophobicity of the protein and that of the surface (tuned by the functionalizing IL). These mechanisms of interaction of biomacromolecules with inorganic hydrophilic solids correspond to the principles of amphiphilic IL-mineral interactions.

BACKGROUND The emergence of monoclonal antibodies (mAbs) as new biopharmaceutical products requires the development of new purification methods that are not only effective but are able to reduce production costs. To address the problematic recovery of mAbs, gum arabic (GA) coated magnetic particles (MPs) were used for the purification of human antibodies from animal cells supernatants. RESULTS MPs were synthesized via co-precipitation and exhibited a spherical-like physical aspect, with an average hydrodynamic diameter of 473 nm and a zeta potential of –26 mV. The adsorption and elution of IgG on these adsorbents was thoroughly studied. Adsorption of human IgG was enhanced at pH 6, for which a qmax of 244 mg IgG g−1 MPs and Kd of 25 mg L−1 were obtained. Increasing salt concentrations at a basic pH (1 mol L−1 NaCl at pH 11) were found to improve the elution of bound IgG. The MPs were challenged with an artificial protein mixture containing human IgG, albumin, insulin and apo-transferrin. An overall yield of 84% was achieved, retrieving 92% of bound IgG. CONCLUSIONS MPs were successfully used for the capture of monoclonal antibodies from two distinct mammalian cell cultures, a Chinese hamster ovary (CHO) and a hybridoma cell culture supernatants. The elution yields were high, ranging between 84% and 94%, with overall yields ranging from 72% to 88%. Final purities of 85% were reached for hybridoma cell supernatants. © 2014 Society of Chemical Industry

Since long ago cellulosic lyotropic liquid crystals were thought as potential materials to produce fibers competitive with spidersilk or Kevlar, yet the processing of high modulus materials from cellulose-based precursors was hampered by their complex rheological behavior. In this work, by using the Rheo-NMR technique, which combines deuterium NMR with rheology, we investigate the high shear rate regimes that may be of interest to the industrial processing of these materials. Whereas the low shear rate regimes were already investigated by this technique in different works [1-4], the high shear rates range is still lacking a detailed study. This work focuses on the orientational order in the system both under shear and subsequent relaxation process arising after shear cessation through the analysis of deuterium spectra from the deuterated solvent water. At the analyzed shear rates the cholesteric order is suppressed and a flow-aligned nematic is observed which for the higher shear rates develops after certain time periodic perturbations that transiently annihilate the order in the system. During relaxation the flow aligned nematic starts losing order due to the onset of the cholesteric helices leading to a period of very low order where cholesteric helices with different orientations are forming from the aligned nematic, followed in the final stage by an increase in order at long relaxation times corresponding to the development of aligned cholesteric domains. This study sheds light on the complex rheological behavior of chiral nematic cellulose-based systems and opens ways to improve its processing. (C) 2015 Elsevier Ltd. All rights reserved.

Fucopol, a fucose-containing exopolysaccharide (EPS) produced by the bacterium Enterobacter A47 DSM 23139 using glycerol as a carbon source, was employed as a new coating material for iron oxide magnetic nanoparticles (MNPs). The coated particles were assessed as nanoprobes for cell labeling by Magnetic Resonance Imaging (MRI). The MNPs were synthesized by a thermal decomposition method and transferred to an aqueous medium by a ligand-exchange reaction with meso-2,3-dimercaptosuccinic acid (DMSA). Covalent binding of EPS to DMSA-stabilized nanoparticles (MNP-DMSA) resulted in a hybrid magnetic-biopolymeric nanosystem (MNP-DMSA-EPS) with a hydrodynamic size of 170 nm, a negative surface charge under physiological conditions and transverse to longitudinal relaxivity ratio, r2/r1, of 148. In vitro studies with two human cell lines (colorectal carcinoma - HCT116 - and neural stem/progenitor cells - ReNcell VM) showed that EPS promotes internalization of nanoparticles in both cell lines. In vitro MRI cell phantoms showed a superior performance of MNP-DMSA-EPS in ReNcell VM, for which the iron dose-dependent MRI signal drop was obtained at relatively low iron concentrations (12-20 mug Fe per ml) and short incubation times. Furthermore, ReNcell VM multipotency was not affected by culture in the presence of MNP-DMSA or MNP-DMSA-EPS for 14 days. Our study suggests that Fucopol-coated MNPs represent useful cell labeling nanoprobes for MRI.

8-β-d-Glucopyranosylgenistein (1), the major component of Genista tenera, was synthesized and showed an extensive therapeutical impact in the treatment of STZ-induced diabetic rats, producing normalization of fasting hyperglycemia and amelioration of excessive postprandial glucose excursions and and increasing β-cell sensitivity, insulin secretion, and circulating insulin within 7 days at a dose of 4 (mg/kg bw)/day. Suppression of islet amyloid polypeptide (IAPP) fibril formation by compound 1 was demonstrated by thioflavin T fluorescence and atomic force microscopy. Molecular recognition studies with IAPP and Aβ1-42 employing saturation transfer difference (STD) confirmed the same binding mode for both amyloid peptides as suggested by their deduced epitope. Insights into the preferred conformation in the bound state and conformers' geometry resulting from interaction with Aβ1-42 were also given by STD, trNOESY, and MM calculations. These studies strongly support 8-β-d-glucopyranosylgenistein as a promising molecular entity for intervention in amyloid events of both diabetes and the frequently associated Alzheimer's disease.

Antisense therapy is a powerful tool for post-transcriptional gene silencing suitable for down-regulating target genes associated to disease. Gold nanoparticles have been described as effective intracellular delivery vehicles for antisense oligonucleotides providing increased protection against nucleases and targeting capability via simple surface modification. We constructed an antisense gold-nanobeacon consisting of a stem-looped oligonucleotide double-labelled with 3′-Cy3 and 5′-Thiol-C6 and tested for the effective blocking of gene expression in colorectal cancer cells. Due to the beacon conformation, gene silencing was directly detected as fluorescence increases with hybridisation to target, which can be used to assess the level of silencing. Moreover, this system was extensively evaluated for the genotoxic, cytotoxic and proteomic effects of gold-nanobeacon exposure to cancer cells. The exposure was evaluated by two-dimensional protein electrophoresis followed by mass spectrometry to perform a proteomic profile and 3-(4,5-Dimethylthiazol-2- Yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay, glutathione-S-transferase assay, micronucleus test and comet assay to assess the genotoxicity. This integrated toxicology evaluation showed that the proposed nanotheranostics strategy does not exhibit significant toxicity, which is extremely relevant when translating into in vivo systems.

Hypertrophic cardiomyopathy (HCM) is a primary disease of the cardiac muscle that occurs mainly due to mutations (>1,400 variants) in genes encoding for the cardiac sarcomere. HCM, the most common familial form of cardiomyopathy, affecting one in every 500 people in the general population, is typically inherited in an autosomal dominant pattern, and presents variable expressivity and age-related penetrance. Due to the morphological and pathological heterogeneity of the disease, the appearance and progression of symptoms is not straightforward. Most HCM patients are asymptomatic, but up to 25% develop significant symptoms, including chest pain and sudden cardiac death. Sudden cardiac death is a dramatic event, since it occurs without warning and mainly in younger people, including trained athletes. Molecular diagnosis of HCM is of the outmost importance, since it may allow detection of subjects carrying mutations on HCM-associated genes before development of clinical symptoms of HCM. However, due to the genetic heterogeneity of HCM, molecular diagnosis is difficult. Currently, there are mainly four techniques used for molecular diagnosis of HCM, including Sanger sequencing, high resolution melting, mutation detection using DNA arrays, and next-generation sequencing techniques. Application of these methods has proven successful for identification of mutations on HCM-related genes. This review summarizes the features of these technologies, highlighting their strengths and weaknesses. Furthermore, current therapeutics for HCM patients are correlated with clinically observed phenotypes and are based on the alleviation of symptoms. This is mainly due to insufficient knowledge on the mechanisms involved in the onset of HCM. Tissue engineering alongside regenerative medicine coupled with nanotherapeutics may allow fulfillment of those gaps, together with screening of novel therapeutic drugs and target delivery systems.

The TupABC system is involved in the cellular uptake of tungsten and belongs to the ABC (ATP binding cassette)-type transporter systems. The TupA component is a periplasmic protein that binds tungstate anions, which are then transported through the membrane by the TupB component using ATP hydrolysis as the energy source (the reaction catalyzed by the ModC component). We report the heterologous expression, purification, determination of affinity binding constants and crystallization of the Desulfovibrio alaskensis G20 TupA. The tupA gene (locus tag Dde_0234) was cloned in the pET46 Enterokinase/Ligation-Independent Cloning (LIC) expression vector, and the construct was used to transform BL21 (DE3) cells. TupA expression and purification were optimized to a final yield of 10 mg of soluble pure protein per liter of culture medium. Native polyacrylamide gel electrophoresis was carried out showing that TupA binds both tungstate and molybdate ions and has no significant interaction with sulfate, phosphate or perchlorate. Quantitative analysis of metal binding by isothermal titration calorimetry was in agreement with these results, but in addition, shows that TupA has higher affinity to tungstate than molybdate. The protein crystallizes in the presence of 30% (w/v) polyethylene glycol 3350 using the hanging-drop vapor diffusion method. The crystals diffract X-rays beyond 1.4 Å resolution and belong to the P2(1) space group, with cell parameters a = 52.25 Å, b = 42.50 Å, c = 54.71 Å, β = 95.43°. A molecular replacement solution was found, and the structure is currently under refinement.