Improved Magneto-Microfluidic Separation of Nanoparticles through Formation of the ß-Cyclodextrin-Curcumin Inclusion Complex.

Molecular adsorption to the nanoparticle surface may switch the colloidal interactions from repulsive to attractive and promote nanoparticle agglomeration. If the nanoparticles are magnetic, then their agglomerates exhibit a much stronger response to external magnetic fields than individual nanoparticles. Coupling between adsorption, agglomeration, and magnetism allows a synergy between the high specific area of nanoparticles (∼100 m2/g) and their easy guidance or separation by magnetic fields. This yet poorly explored concept is believed to overcome severe restrictions for several biomedical applications of magnetic nanoparticles related to their poor magnetic remote control. In this paper, we test this concept using curcumin (CUR) binding (adsorption) to ß-cyclodextrin (ßCD)-coated iron oxide nanoparticles (IONP). CUR adsorption is governed by host-guest hydrophobic interactions with ßCD through the formation of 1:1 and, possibly, 2:1 ßCD:CUR inclusion complexes on the IONP surface. A 2:1 stoichiometry is supposed to promote IONP primary agglomeration, facilitating the formation of the secondary needle-like agglomerates under external magnetic fields and their magneto-microfluidic separation. The efficiency of these field-induced processes increases with CUR concentration and ßCD surface density, while their relatively short timescale (<5 min) is compatible with magnetic drug delivery application.

Biophysics and protein corona analysis of Janus cyclodextrin-DNA nanocomplexes. Efficient cellular transfection on cancer cells.

The self-assembling processes underlining the capabilities of facially differentiated ("Janus") polycationic amphiphilic cyclodextrins (paCDs) as non-viral gene nanocarriers have been investigated by a pluridisciplinary approach. Three representative Janus paCDs bearing a common tetradecahexanoyl multitail domain at the secondary face and differing in the topology of the cluster of amino groups at the primary side were selected for this study. All of them compact pEGFP-C3 plasmid DNA and promote transfection in HeLa and MCF-7 cells, both in absence and in presence of human serum. The electrochemical and structural characteristics of the paCD-pDNA complexes (CDplexes) have been studied by using zeta potential, DLS, SAXS, and cryo-TEM. paCDs and pDNA, when assembled in CDplexes, render effective charges that are lower than the nominal ones. The CDplexes show a self-assembling pattern corresponding to multilamellar lyotropic liquid crystal phases, characterized by a lamellar stacking of bilayers of the CD-based vectors with anionic pDNA sandwiched among them. When exposed to human serum, either in the absence or in the presence of pDNA, the surface of the cationic CD-based vector becomes coated by a protein corona (PC) whose composition has been analyzed by nanoLC-MS/MS. Some of the CDplexes herein studied showed moderate-to-high transfection levels in HeLa and MCF-7 cancer cells combined with moderate-to-high cell viabilities, as determined by FACS and MTT reduction assays. The ensemble of data provides a detail picture of the paCD-pDNA-PC association processes and a rational base to exploit the protein corona for targeted gene delivery on future in vivo applications.

Conformationally-locked C-glycosides: tuning aglycone interactions for optimal chaperone behaviour in Gaucher fibroblasts.

A series of conformationally locked C-glycosides based on the 3-aminopyrano[3,2-b]pyrrol-2(1H)-one (APP) scaffold has been synthesized. The key step involved a totally stereocontrolled C-Michael addition of a serine-equivalent C-nucleophile to tri-O-benzyl-2-nitro-D-galactal, previously published by the authors. Stereoselective transformations of the Michael adduct allowed us the synthesis of compounds with mono- or diantennated aglycone moieties and different topologies. In vitro screening showed highly selective inhibition of bovine liver ß-glucosidase/ß-galactosidase and specific inhibition of human ß-glucocerebrosidase among lysosomal glycosidases for compounds bearing palmitoyl chains in the aglycone, with a marked dependence of the inhibition potency upon their number and location. Molecular dynamics simulations highlighted the paramount importance of an optimal orientation of the hydrophobic substituent to warrant efficient non-glycone interactions, which are critical for the binding affinity. The results provide a rationale for the strong decrease of the inhibition potency of APP compounds on going from neutral to acidic pH. The best candidate was found to behave as pharmacological chaperone in Gaucher fibroblasts with homozygous N370S and F213I mutations, with enzyme activity enhancements similar to those encountered for the reference compound Ambroxol.

Correlations between changes in intestinal microbiota composition and performance parameters in broiler chickens.

Growing male Cobb broiler chickens were fed on diets supplemented with additives reported as able to influence intestinal microbiota composition. The diets used were a balanced commercial diet (no additive), inulin (20 g/kg), fructose caramel (FC, 20 g/kg) and the garlic derivative PTS-O (propyl propane thiosulfonate, 45 and 90 mg/kg diet). The composition of the intestinal microbiota was analysed by qPCR at different points of the intestinal tract, and a number of nutritional parameters were also determined. The relative amounts of bacteroides (bacteroides/total bacteria) in the ileal contents correlated (p < 0.05) positively with faecal NDF, ADF, hemicellulose and cellulose digestibility. The relative amounts of Escherichia-Shigella (Escherichia-Shigella/total bacteria) in the crop contents correlated (p = 0.05) negatively with weight gain of broilers. Faecal N digestibility correlated (p < 0.05) negatively with total bacteria in the ileal contents of chickens. The relative amounts of Escherichia-Shigella (Escherichia-Shigella/total bacteria) in the caecal contents correlated (p = 0.05) negatively with faecal fat digestibility of broilers. Total bacteria in ileal or caecal contents of growing chickens correlated (p < 0.05) negatively with ileal N digestibility. The results here reported suggest that positive or negative correlations can be found between performance parameters and changes in intestinal microbiota composition of growing broiler chickens.

Regulatory and metabolic adaptations in the nitrogen assimilation of marine picocyanobacteria.

Prochlorococcus and Synechococcus are the two most abundant photosynthetic organisms on Earth, with a strong influence on the biogeochemical carbon and nitrogen cycles. Early reports demonstrated the streamlining of regulatory mechanisms in nitrogen metabolism and the removal of genes not strictly essential. The availability of a large series of genomes, and the utilization of latest generation molecular techniques have allowed elucidating the main mechanisms developed by marine picocyanobacteria to adapt to the environments where they thrive, with a particular interest in the strains inhabiting oligotrophic oceans. Given that nitrogen is often limited in those environments, a series of studies have explored the strategies utilized by Prochlorococcus and Synechococcus to exploit the low concentrations of nitrogen-containing molecules available in large areas of the oceans. These strategies include the reduction in the GC and the cellular protein contents; the utilization of truncated proteins; a reduced average amount of N in the proteome; the development of metabolic mechanisms to perceive and utilize nanomolar nitrate concentrations; and the reduced responsiveness of key molecular regulatory systems such as NtcA to 2-oxoglutarate. These findings are in sharp contrast with the large body of knowledge obtained in freshwater cyanobacteria. We will outline the main discoveries, stressing their relevance to the ecological success of these important microorganisms.

Mixotrophy in marine picocyanobacteria: use of organic compounds by Prochlorococcus and Synechococcus.

Marine picocyanobacteria of the Prochlorococcus and Synechococcus genera have been longtime considered as autotrophic organisms. However, compelling evidence published over the last 15 years shows that these organisms can use different organic compounds containing key elements to survive in oligotrophic oceans, such as N (amino acids, amino sugars), S (dimethylsulfoniopropionate, DMSP), or P (ATP). Furthermore, marine picocyanobacteria can also take up glucose and use it as a source of carbon and energy, despite the fact that this compound is devoid of limiting elements and can also be synthesized by using standard metabolic pathways. This review will outline the main findings suggesting mixotrophy in the marine picocyanobacteria Prochlorococcus and Synechococcus, and its ecological relevance for these important primary producers.

Regulation of the mammalian pineal by non-rod, non-cone, ocular photoreceptors.

In mammals, ocular photoreceptors mediate an acute inhibition of pineal melatonin by light. The effect of rod and cone loss on this response was assessed by combining the rd mutation with a transgenic ablation of cones (cl) to produce mice lacking both photoreceptor classes. Despite the loss of all known retinal photoreceptors, rd/rd cl mice showed normal suppression of pineal melatonin in response to monochromatic light of wavelength 509 nanometers. These data indicate that mammals have additional ocular photoreceptors that they use in the regulation of temporal physiology.

Mannose-coated polydiacetylene (PDA)-based nanomicelles: synthesis, interaction with concanavalin A and application in the water solubilization and delivery of hydrophobic molecules.

Carbohydrate-lectin interactions are involved in a number of relevant biological events including fertilization, immune response, cell adhesion, tumour cell metastasis, and pathogen infection. Lectins are also tissue specific, making carbohydrates not only promising drug candidates but also excellent low molecular weight ligands for active drug delivery system decorations. In order for these interactions to be effective multivalency is essential, as the interaction of a lectin with its cognate monovalent carbohydrate epitope usually takes place with low affinity. Unlike the covalent approach, supramolecular self-assembly of glyco-monomers mediated by non-covalent forces allows accessing multivalent systems with diverse topology, composition, and assembly dynamics in a single step. In order to fine-tune the size and sugar adaptability of spherical micelles at the nanoscale for an optimal glycoside cluster effect, herein we report the synthesis of mannose-coated static micelles from diacetylene-based mannopyranosyl glycolipids differing in the length of the poly(ethyleneglycol) (PEG) chains and the oxidation state of the anomeric sulfur atom. The reported shot-gun like synthetic approach for the synthesis of dilution-insensitive micelles is based on the ability of diacetylenic-based neoglycolipids to self-assemble into micelles in water and to undergo an easy photopolymerization by a simple irradiation at 254 nm. The affinity of the obtained 6 nanosystems was assessed by enzyme-linked lectin assay (ELLA) using the mannose-specific concanavalin A lectin as a model receptor. Relative binding potency enhancements, compared to methyl α-d-mannopyranoside used as control, from 20-, to 29- to 300-fold on a sugar molar basis were observed for micelles derived from sulfonyl-, sulfinyl- and thioglycoside monomers with a tatraethyleneglycol spacer, respectively, indicative of a significant cluster glycoside effect. Moreover, pMic1 micelles are able to solubilize and slowly liberate lipophilic clinically relevant drugs, and show the enhanced cytotoxic effect of docetaxel toward prostate cancer cells. These findings highlight the potential of mannose-coated photopolymerized micelles pMic1 as an efficient nanovector for active delivery of cytotoxic hydrophobic molecules.

[Pharmaceutical use of cyclodextrines: perspectives for drug targeting and control of membrane interactions]. / Les cyclodextrines en pharmacie: perspectives pour le ciblage d'actifs thérapeutiques et le contrôle d'interactions membranaires.

Cyclomaltooligosaccharides (cyclodextrins, CDs) comprise a family of biocompatible cage devices which have been developed during the last thirty years in order to improve the solubility, stability and the bioavailability of drugs. Chemical modification usually improves the solubility and solubilisation properties and generally alleviates the renal toxicity of native cyclodextrins. Red cell lysis, which is ascribed to membrane interactions is also monitored. Selective and commercially accessible functionalisation processes are now available which avoid the problems of heterogeneity commonly found with the existing industrial approaches. These allow a convenient access to modular structures which could fit the molecular characteristics of the host ("bouquet" and dimeric CDs). Grafting of saccharide ligands which are recognised by membrane proteins is another promising aspect for the transport and targeting of drugs and the control of cell interactions. Several topological aspects of ligand presentation toward a membrane lectin have been assessed with concanavalin A and mannosyl CD-dendrimers and the results have been extended to molecular targeting to macrophages. Advantage has been taken of the autoassociation properties of amphiphilic derivatives of cyclodextrins for the preparation of stable nanoparticles of interest for the transport and targeting of drugs and macromolecular systems.

The mPer1 clock gene expression in the rd mouse suprachiasmatic nucleus is affected by the retinal degeneration.

Endogenous rhythms of mammals are controlled by the clock located in the suprachiasmatic nucleus (SCN). The molecular mechanism of a clock involves transcription/translation-based feedback loops in which the expression of the so called "clock genes" is suppressed periodically by their protein products. Previous studies reported influence of the eye itself on the circadian oscillation of the SCN, apart from the well-known photic readjustment of the central clock. With this in mind, we decided to analyze the mPer1 clock gene expression in the retinally degenerate (rd) mouse SCN by means of immunohistochemical techniques. Our objective was to detect possible alterations of the daily endogenous oscillation of PER1 protein in the SCN of these rd mice, as well as to make clear whether or not this protein was involved in the resetting of the central clock in a manner similar to wild-type animals. We found that the endogenous levels of PER1 protein were reduced in the SCN of rd mice throughout the 24-h cycle, which suggests that loss of classic photoreceptors influences somehow the main mechanism of the SCN clock. Light stimulation induced a parallel increase of Per1 expression at the subjective night, but not at the subjective day, in both rd and wild-type mice. Therefore, SCN readjustment by light in the rd mice occurs with a pattern similar to wild-type controls, despite the reduced PER1 protein levels detected. The effect of retinal degeneration on the circadian system and the possible interactions between the retinal and the SCN clocks are discussed.

Structure and serological analysis of the Hafnia alvei 481-L O-specific polysaccharide containing phosphate in the backbone chain.

The lipopolysaccharide was extracted from cells of Hafnia alvei 481-L bacterial strain and, after mild acid hydrolysis, the O-specific polysaccharide was isolated and characterised. On the basis of chemical analyses and NMR spectroscopic studies of the polysaccharide and oligosaccharides obtained after Smith degradation, or hydrogen fluoride treatment, it was found that the repeating unit of the O-specific polysaccharide is a phosphorylated hexasaccharide: [see text]. The biological repeating unit of the H. alvei 481-L O-antigen has galactose phosphate at the nonreducing terminus. Serological tests indicate that this strain represents an individual serotype in the H. alvei genus.

Tuning of glyconanomaterial shape and size for selective bacterial cell agglutination.

Multivalent glycosystems are potential candidates for anti-adhesive therapy, a non-lethal approach against the ever increasing antibiotic resistance of pathogenic bacteria. In order to fine-tune the glyconanomaterial size and shape for selective bacterial cell agglutination, herein we report the synthesis of sugar-coated dynamic and polymeric 3D-micelles and 1D-carbon nanotubes. The reported shot-gun like synthetic approach is based on the ability of diacetylenic-based neoglycolipids to self-assemble into micelles in water and hierarchically self-assemble into hemimicelles on a single-walled carbon nanotube surface. The affinity of the nanosystems was preliminarily assessed by enzyme-linked lectin assay (ELLA) using the mannose-specific Concanavalin A lectin as a model receptor. Relative binding potency enhancements, compared to methyl α-d-mannopyranoside used as control, from 10- to 25- to 2340-folds in sugar molar basis were observed when passing from 3D dynamic micelles to static micelles, to 1D-mannose coated carbon nanotubes, respectively, indicative of a significant cluster glycoside effect. Importantly, these results were confirmed in vivo showing that the 1D-glyconanoring-coated carbon nanotubes efficiently and selectively regulate the agglutination and proliferation of the enterobacteria Escherichia coli type 1 fimbriae. These findings highlight the potential of sugar coated nano-materials as novel and effective tools in the control of bacterial pathogenesis.

Trehalose-based Janus cyclooligosaccharides: the "Click" synthesis and DNA-directed assembly into pH-sensitive transfectious nanoparticles.

The convergent preparation of Janus molecular nanoparticles by thiourea-"clicking" of α,α'-trehalose halves has been implemented; the strategy allows access to macrocyclic derivatives with seggregated cationic and lipophilic domains that in the presence of DNA undergo pH-dependent self-assembly into lamellar superstructures, as established by electrochemical, structural (SAXS), microscopical (TEM) and computational techniques, that mediate transfection in vitro and in vivo.

Regulation of glutamine synthetase by metal-catalyzed oxidative modification in the marine oxyphotobacterium Prochlorococcus.

The inactivation of glutamine synthetase (GS; EC 6.3.1.2) by metal-catalyzed oxidation (MCO) systems was studied in several Prochlorococcus strains, including the axenic PCC 9511. GS was inactivated in the presence of various oxidative systems, either enzymatic (as NAD(P)H+NAD(P)H-oxidase+Fe(3+)+O(2)) or non-enzymatic (as ascorbate+Fe(3+)+O(2)). This process required the presence of oxygen and a metal cation, and is prevented under anaerobic conditions. Catalase and peroxidase, but not superoxide dismutase, effectively protected the enzyme against inactivation, suggesting that hydrogen peroxide mediates this mechanism, although it is not directly responsible for the reaction. Addition of azide (an inhibitor of both catalase and peroxidase) to the MCO systems enhanced the inactivation. Different thiols induced the inactivation of the enzyme, even in the absence of added metals. However, this inactivation could not be reverted by addition of strong oxidants, as hydrogen peroxide or oxidized glutathione. After studying the effect of addition of the physiological substrates and products of GS on the inactivation mechanism, we could detect a protective effect in the case of inorganic phosphate and glutamine. Immunochemical determinations showed that the concentration of GS protein significantly decreased by effect of the MCO systems, indicating that inactivation precedes the degradation of the enzyme.

Occurrence of Only One Form of Glutamine Synthetase in the Green Alga Monoraphidium braunii.

Anion-exchange chromatography of crude extracts from the green alga Monoraphidium braunii yielded two glutamine synthetase (GS) activities. The ratio of activities was markedly different when crude extracts were subjected to various processing conditions but was not influenced by environmental factors of cell cultures. However, high performance liquid chromatography anion-exchange chromatograms showed only one GS if the crude extracts were processed immediately after cell disruption. Moreover, standard chromatography of crude extracts obtained in the absence of dithioerythritol, a reductant generally used in disruption buffers, yielded a single activity peak. Enzyme samples from the two activities obtained in the presence of dithioerythritol were purified for physicochemical characterization and antibody production. Both enzyme samples exhibited similar reactions to different inactivating agents and were undistinguishable by size-exclusion chromatography and native polyacrylamide gel electrophoresis. Additionally, the two GS preparations showed absolute antigenic identity as demonstrated by immunodiffusion and immunoblotting experiments. Immunocytochemistry of M. braunii cryosections evidenced a chloroplast-specific distribution of the enzyme, which rules out the existence of a cytoplasmic counterpart. All these results support the proposal that M. braunii possesses only one form of GS.

Darkness during early postnatal development is required for normal circadian patterns in the adult rat.

Early light experience influences the brain during development. Perinatal light exposure has an important effect on the development of the circadian system, although the role of quantity versus quality of light in this process is still unclear. We tested the development of the circadian rhythm of locomotor activity under constant bright light from the day of weaning, of six groups of rats raised under different light conditions during suckling. Results indicated that when rats received daily darkness during suckling (rats reared under constant darkness or light-dark cycles with dim or bright light) became arrhythmic when exposed to continuous bright light after weaning. However, those rats reared in the absence of darkness (constant dim or bright light, or alternating dim and bright light) developed a circadian rhythm, which was stronger and had a shorter period depending on the quantity of light received during suckling. Vasointestinal polypeptide immunoreactivity in the suprachiasmatic nucleus (SCN) was higher in those rats with weaker rhythms. However, no apparent differences among these groups were found in the melanopsin-expressing retinal ganglion cells, which provide the SCN with light input in the photoentrainment process. When bright light was shifted to dim light in three of the groups on day 57 after weaning, all of them generated a circadian rhythm with a longer period in those rats previously arrhythmic. Our results indicate the importance of the amount of light received at the early stages of life in the development of the circadian system and suggest that darkness is needed for the normal development of circadian behaviour.

Effects of feed additives on ileal mucosa-associated microbiota composition of broiler chickens.

The effects of dietary supplementation with 2 recently developed feed additives on the composition of the mucosa-associated microbiota of the ileum were studied in growing broiler chickens. A total of 48 male 1-d-old broiler chickens of the Cobb 500 strain were distributed in 4 treatments with 2 replicates of 6 birds each. The 2 additives tested were a di-d-fructose dianhydride­enriched caramel (FC) and the garlic derivative propyl propane thiosulfonate (PTS-O). Dietary treatments were a control (commercial diet with no additive), INU (20 g inulin/kg diet), CAR (20 g FC/kg diet), and GAR (90 mgPTS-O/kg diet). As a result of this study, inulin supplementation resulted in lower (P < 0.05) and FC feeding resulted in higher (P < 0.05) Blautia coccoides/Eubacterium rectale log10 number of copies respect to controls. Higher (P < 0.05) bifidobacteria log10 number of copies with respect to the controls was determined in the ileal mucosa of birds fed the PTS-O­supplemented diet. Denaturing gradient gel electrophoresis and PCR analysis on Bifidobacterium spp. revealed the presence of Bifidobacterium longum, Bifidobacterium pseudolongum, and Bifidobacterium pseudocatenulatum in samples from chickens fed the control and the PTS-O­supplemented diet. Bifidobacterium longum was exclusively found in poultry fed the control diet, whereas B. pseudocatenulatum was found only in poultry fed the PTS-O­supplemented diet. This study showed that both PTS-O and FC were able to modulate the composition of the ileal mucosa-associated microbiota of growing broiler chickens. Finally, in addition to B. pseudolongum, the presence of B. longum and B. pseudocatenulatum, species not previously described in intestinal samples of broilers, was also demonstrated.

Identification of vertebrate deep brain photoreceptors.

Since the beginning of this century evidence has accumulated which demonstrates that nonmammalian vertebrates possess photoreceptors situated deep within the brain. These photoreceptors have been implicated in several different areas of physiology, but in all species examined, they play a critical role in the regulation of circadian and reproductive responses to light. Many attempts have been made to localize these sensory cells over the past 50 years, but until recently all attempts have failed. As a result, this important sensory system remains largely unexplored. Recent attempts to localize these photoreceptors, in a range of vertebrates, using combined antibody and biochemical approaches has met with some success. However, inconsistencies have emerged. Published and preliminary data raise the possibility of several types of encephalic photoreceptor photopigment (cone-like, rod-like or different from both), and depending on species at least two types of photoreceptor cell: CSF-contacting neurons (larval lamprey, reptiles and birds) and classical neurosecretory neurons within the nucleus magnocellularis preopticus (NMPO)(fish and amphibians).

Age-related morphometric changes in the pineal gland. A comparative study between C57BL/6J and CBA mice.

Relatively little is known about the effects of melatonin on the aging of the pineal, the organ which is the main place for synthesis of this hormone. Using simple morphometric methods, some parameters of the pineal gland, such as total volume, number of pinealocytes and pinealocyte volume were estimated in two mice strains: normal CBA and melatonin-deficient C57BL/6J. Two age groups, 6 weeks and 10 months, were studied in order to evaluate possible differential age-related changes between both strains. Pineals of both strains have similar morphometric and morphological features at 6 weeks of age. This suggests that pineal development, which has already concluded at 6 weeks of age, is not affected by the absence of melatonin synthesis in the pinealocytes. Later on, CBA pineal showed an increase in size caused by cellular hypertrophy. In contrast, the C57BL/6J pineal volume decreased by loss of pinealocytes in the same period of time. Semithin sections analysed by light microscopy did not show that this cell death was evident in the C57BL/6J strain at any of the ages studied. Thus, a gradual loss of pinealocytes could be hypothesised in these pineals. These results suggest that pineal melatonin could have a role in the maintenance of pinealocyte viability and the increase of pineal size which takes place after development. The abnormal pattern observed in the C57BL/6J pineal should be taken into account in future studies on this gland.

The distribution of corticotropin-releasing factor immunoreactive neurons and nerve fibres in the brain of Gambusia affinis and Salmo trutta.

The study was carried out on the distribution of neurons and fibres which contain the Corticotropin releasing factor-like (CRF) immunoreactivity in the encephalon of two species of teleosts, Gambusia affinis and Salmo trutta. The peroxidase-antiperoxidase (PAP) immunocytochemical technique was employed. The present study has shown differences between both species. In Gambusia affinis, positive neurons were observed in the area ventralis telencephali pars lateralis (VLT), in the nucleus praeopticus (NPO) and in the nucleus lateralis tuberis (NLT). The immunoreactive fibres were in the area ventralis telencephali, in the preoptic hypophyseal tract and in the hypophysis. In Salmo trutta the immunoreactive cells were seen in the pars magnocellularis and pars parvocellularis of the NPO and in cerebrospinal fluid (CSF) contacting neurons of the NLT. The pattern of distribution of immunoreactive fibres in Salmo trutta was different from that in Gambusia affinis. In addition to the distribution of perikarya in Gambusia affinis (in the VLT and in the preoptic hypophyseal tract), fibres were also observed in the tubero-hypophyseal tract and in the posterior hypothalamus. The hypophysis of Salmo trutta also presents an extensive labelling. The interspecific differences shown in the present study should be due to the different degree of evolution in the two species studied and to other causes, such as environmental ones.