Efficient purification of chromatin architectural proteins:histones, HMGB proteins and FKBP3 (FKBP25) immunophilin

A two-step process of high ionic strength lysis of chicken erythrocyte cell nuclei followed by cation-exchange chromatography has separated at very high yield all the histone and HMGB (high-mobility group B) nuclear proteins, except the less-soluble histone tetramers. Surprisingly high yields of the nuclear immunophilin FKBP3 (FKBP25) and Hsp70 (heat-shock protein 70) co-fractionate with HMGB1 and HMGB3. Furthermore, these proteins can be separated by anion-exchange chromatography. The purified nuclear proteins retain their native, post-translational modification (PTM) marks, including those associated with chromatin-fibre remodelling. These marks are intimately associated with the control of the cell cycle. The methods herein are therefore of value for targeting these and other nuclear proteins for future proteomic studies in healthy and diseased cells. This journal is © 2012 The Royal Society of Chemistry.

Oxygen, pH and calcium dynamics and fluxes at the thallus surface under ambient (8.1) and low (7.8) seawater pH and across a range of irradiances

Presently, an incomplete mechanistic understanding of tropical reef macroalgae photosynthesis and calcification restricts predictions of how these important autotrophs will respond to global change. Therefore, we investigated the mechanistic link between inorganic carbon uptake pathways, photosynthesis and calcification in a tropical crustose coralline alga (CCA) using microsensors. We measured pH, oxygen (O2), and calcium (Ca2+) dynamics and fluxes at the thallus surface under ambient (8.1) and low (7.8) seawater pH (pHSW) and across a range of irradiances. Acetazolamide (AZ) was used to inhibit extracellular carbonic anhydrase (CAext), which mediates hydrolysis of HCO3-, and 4,4' diisothiocyanatostilbene-2,2'-disulphonate (DIDS) that blocks direct HCO3- uptake by anion exchange transport. Both inhibited photosynthesis, suggesting both diffusive uptake of CO2 via HCO3- hydrolysis to CO2 and direct HCO3- ion transport are important in this CCA. Surface pH was raised approximately 0.3 units at saturating irradiance, but less when CAext was inhibited. Surface pH was lower at pHSW 7.8 than pHSW 8.1 in the dark, but not in the light. The Ca2+ fluxes were large, complex and temporally variable, but revealed net Ca2+ uptake under all conditions. The temporal variability in Ca2+ dynamics was potentially related to localized dissolution during epithallial cell sloughing, a strategy of CCA to remove epiphytes. Simultaneous Ca2+ and pH dynamics suggest the presence of Ca2+/H+ exchange. Rapid light-induced H+ surface dynamics that continued after inhibition of photosynthesis revealed the presence of a light-mediated, but photosynthesis-independent, proton pump. Thus, the study indicates metabolic control of surface pH can occur in CCA through photosynthesis and light-inducible H+ pumps. Our results suggest that complex light-induced ion pumps play an important role in biological processes related to inorganic carbon uptake and calcification in CCA.

Obtenção de organovermiculitas utilizando tensoativos e microemulsões e suas aplicações na separação de isômeros do Xileno

Surfactants are versatile organic compounds that have, in a single molecule, double chemical affinity. The surfactant molecule is composed by a hy drophobic tail group, a hydrocarbon chain (linear, branched, or mixed), and by a hydrophilic head group, which contains polar groups that makes it able to be applied in the organophilization process of natural clays. Microemulsions are microheterogeneous b lends composed by: a surfactant, an oily phase (non - polar solvent), an aqueous phase, and, sometimes, a co - surfactant (short - chain alcohol). They are systems with thermodynamic stability, transparent, and have high solubility power. Vermiculite is a clay m ineral with an expandable crystalline structure that has high cation exchange capacity. In this work vermiculite was used to obtain organoclays. The ionic surfactants dodecyl ammonium chlori de (DDAC) and cetyltrimethylammonium bromide (C 16 TAB) were used in the organophilization process. They were used as surfactant aqueous solutions and, for DDAC, as a microemulsion system. The organoclays were used to promote the separation of binary mixtures of xylene isomers (ortho - and meta - xylene). Dif ferent analytical techniques were used to characterize microemulsion systems and also the nanoclays. It was produced a water - rich microemulsion system with 0.92 nm droplet average diameter. The vermiculite used in this work has a cationic exchange capacity of 172 meq/100g and magnesium as main cation (24.25%). The basal spacing of natural vermiculite and organo - vermiculites were obtained by X - ray Diffraction technique. The basal spacing was 1.48nm for natural vermiculite, 4.01nm for CTAB - vermiculite (CTAB 4 ) , and 3.03nm for DDAC - vermiculite (DDAC M1A), that proves the intercalation process. Separation tests were carried out in glass columns using three binary mixtures of xylene (ortho - xylene and meta - xylene). The results showed that the organovermiculite pre sented an enhanced chemical affinity by the mixture of hydrocarbons, when compared with the natural vermiculite, and also its preference by ortho - xylene. A factorial experimental design 2 2 with triplicate at the central point was used to optimize the xylen e separation process. The experimental design revealed that the initial concentration of isomers in the mixture and the mass of organovermiculite were the significant factors for an improved separation of isomers. In the experiments carried out using a bin ary mixture of ortho - xylene and meta - xylene (2:1), after its percolating through the organovermiculite bed (DDAC M1), it was observed the preference of the organoclay by the ortho - xylene isomer, which was retained in greater quantity than the meta - xylene o ne. At the end of the treatment, it was obtained a final concentration in meta - xylene of 47.52%.

Remoção de corantes têxteis em solução aquosa utilizando bentonita natural e organofílica

Searches using organoclays have been the subject of great interest due to its wide application in industry and removal of environmental pollutants. The organoclays were obtained using bentonite (BEN) and cationic surfactants: hexadecyltrimethyl ammonium bromide (HDTMA-Br) and trimethyloctadecyl ammonium bromide (TMOA-Br) in ratios of 50 and 100 % of its ion exchange capacity. The materials were characterized by the techniques of X-ray diffraction (DRX), infrared spectroscopy (IR), X-ray fluorescence (FRX), thermal analysis (TA) and scanning electron microscopy (SEM). The bentonite and organobentonite were used on the adsorption of dyes, Remazol Blue RR (AZ) and Remazol Red RR (VM) in aqueous solution. The adsorption models of Langmuir and Freundlich were used for mathematical description of sorption equilibrium data and obtain the constants of the isotherms. The Freundlich model fit to the data for adsorption equilibrium of bentonite, on the other hand both the model fit to the Langmuir adsorption test of organoclays. The adsorption processes using adsorbents with both dyes interspersed with HDTMA-Br show endothermic and exothermic nature, respectively.

Materiais bionanocompósitos a base de argilominerais e hidróxidos duplos lamelares como sistemas de liberação de fármacos

Bionanocomposites systems clay base (montmorillonite and sepiolite), layered double hidroxides and biopolymers (carboxymethylcellulose and zein) were evaluated as topical delivery systems with antibacterial activity and as oral delivery systems. For this study, neomycin, a topical antibiotic, indicated mainly for open wound infections. The drug amoxicillin, an antibiotic indicated mainly for throat infections, were also used in this study. Both antibiotics were used as model drugs. Initially, drugs were incorporated directly into the biopolymer matrix, comprising the combination of carboxymethylcellulos and zein, being conformed as movies and balls and evaluated for their antibacterial activity and controlled release simulating gastrointestinal fluids. Moreover, hybrids materials have been prepared where the neomycin drug was incorporated into the lamellar inorganic solids, such as montmorillonite by ion exchange reaction, and the fibrous type, such as sepiolite by adsorption in aqueous solution. But the drug amoxicillin was incorporated into layered double hydroxides by anion exchange and montmorillonite by cation exchange. The resulting hybrids were in turn combined with the biopolymer matrix yielding bionanocomposites shaped materials such as films were tested for their antibacterial activity, and the shaped materials beads were tested for their release in the gastrointestinal fluids. Through the analysis of various physico-chemical techniques, we observed the interactions between the studied materials, the formation of hybrids materials, obtaining the bionanocomposites materials and material efficiency when applied in controlled release of drugs both topical and use oral mainly influenced by the presence of zein, are promising as topical delivery systems and oral drugs.

Water temperature, salinity, DOC content and THNS concentration in samples taken during POLARSTERN cruise to the Fram Strait and Greenland Sea

Dissolved organic matter (DOM) was isolated with XAD-2 and 4 resins from different water masses of the Greenland Sea and Fram Strait. The contribution of XAD-extractable dissolved organic carbon (DOC), operationally defined as 'recalcitrant' or humic substances, to total DOC was in the range of 45 ± 9% in surface waters and 60 ± 6% in deep waters. The carbohydrate concentration and composition were determined using the l-tryptophan/sulfuric acid method (for the bulk carbohydrate concentration, TCHO) and high performance anion-exchange chromatography after sulfuric acid hydrolysis (for the distribution of total hydrolysable neutral sugars, THNS). Carbohydrates contributed up to 6.8% to both total and recalcitrant DOC. TCHO contribution to total DOC decreased with depth from on average 4.1 ± 1.2% in surface waters to 2.2 ± 1.0% in deep waters, whereas the THNS contribution was similar in both layers, accounting for 2.5 ± 1.6% (surface) and 2.4 ± 0.2% (at depth). TCHO contribution to XAD-extractable DOC also decreased with depth from 4.5 ± 1.7% to 2.1 ± 1.0%, whereas THNS contribution was almost constant, with yields of 0.5 ± 0.3% for surface samples and 0.6 ± 0.1% at depth. The molecular size distribution of the recalcitrant DOM showed for all fractions a clear trend towards small molecules in the deep sea. More than half of the XAD-extractable carbohydrates of surface samples and more than 70% of deep sea samples were found in the nonpolar fraction from XAD, which was eluted with methanol. Glucose was the dominant carbohydrate in the surface water samples, whereas in the deep sea the composition was more uniform. In the XAD extracts, the compositions were less variable than in the original samples. The neutral sugar composition, in particular glucose and the deoxysugars, is indicative of the diagenetic state of the extracted DOM. The molar ratio (fucose + rhamnose)/(arabinose + xylose) was lowest for deep sea extractable DOM, indicating a high contribution of material modified by microorganisms. The THNS composition and distribution reveal that "recalcitrant" carbohydrates are heteropolysaccharides, carbohydrate units incorporated into a framework of a highly nonpolar structure with a lack of functional groups.

Mineralogy and petrology of Black Sea Basin sediments

The origin and modes of transportation and deposition of inorganic sedimentary material of the Black Sea were studied in approximately 60 piston, gravity, and Kasten cores. The investigation showed that the sediment derived from the north and northwest (especially from the Danube) has a low calcite-dolomite ratio and a high quartz-feldspar ratio. Rock fragments are generally not abundant; garnet is the principal heavy mineral and illite is the predominant clay mineral. This sedimentary material differs markedly from that carried by Anatolian rivers, which is characterized by a high calcite-dolomite ratio and a low quartz-feldspar ratio. Rock fragments are abundant; pyroxene is the principal heavy mineral and montmorillonite is the predominant clay mineral. In generel, the clay fraction is large in all sediments (27.6-86.9 percent), and the lateral distributian indicates an increase in clay consent from the coasts toward two centers in the western and eastern Black Sea basin. Illite is the most common clay mineral in the Black Sea sediments. The lateral changes in composition of the clay mineral can easily be traced to the petrologic character of northern (rich in illite) and southern (rich in montmorillonite) source areas. In almost all cores, a rhythmic change of the montmorillonite-illite ratio with depth was observed. These changes may be related to the changing influence of the two provinces during the Holocene and late Pleistocene. Higher montmorillonite content seems to indicate climctic changes, probably stages of glaciation end permafrost in the northern area, at which time the illite supply was diminished to a large extent. The composition of the sand fraction is relatad to the different petrologic and morphologic characteristics of two major source provimces: (1) a northern province (rich in quartz, feldspars, and garnet) characterized by a low elevation, comprising the Danube basin area and the rivers draining the Russian platform; and (2) a southern province (rich in pyroxene and volcanic and metamorphic rocks) in the mountainous region of Anatolia and the Caucasus, characterized by small but extremely erosive rivers. The textural properties (graded bedding) of the deep-sea send layers clearly suggest deposition from turbidity currents. The carbonate content of the contemporary sediments ranges from 5 to 65 percent. It increases from the coast to a maximum in two centers in the western and eastern basin. This pattern reflects the distribution of the <2-µm fraction. The contemporary mud sedimentation is governed by two important factors: (1) the deposition of terrigenous allochthonous material of low carbonate content originating from the surrounding hinterland (northern and southern source areas), and (2) the autochthonous production of large quantities of biogenic calcite by coccolithophores during the last period of about 3,000-4,000 years.

Ex situ sulphate reduction and methane oxidation rates of sediment at the rim of a vesicomyd clam colony in the Japan Deep Sea Trench (dive 956)

Sediment samples were collected from the rim of a large vesicomyid clam colony in the Japan Deep Sea Trench. Immediately after sample recovery onboard, the sediment core was sub-sampled for ex situ rate measurements. Sulfate reduction and anaerobic oxidation of methane were measured ex situ by the whole core injection method with three replicate measurements for each method. We incubated the samples at in situ temperature (1.5°C) for 48 hours with either 14C-methane (dissolved in water, 2.5 kBq) or carrier-free 35S-sulfate (dissolved in water, 50 kBq). Sediment was fixed in 25 ml sodium hydroxide (NaOH) solution (2.5%, w/v) or 20 ml ZnAc solution (20%, w/v) for AOM or SR, respectively. Turnover rates were measured as previously described (Kallmeyer et al., 2004; Treude et al., 2003).

Preparação de catalisadores para reações de esterificação do ácido oleico baseados em matrizes polímericas sulfonadas POLI(1- FENILETILENO) (PS) e POLI(1-CLOROETILENO) (PVC)

Chemical modification of polymer matrices is an alternative way to change its surface properties. The introduction of sulfonic acid groups in polymer matrices alter properties such as adhesion, wettability, biocampatibility, catalytic activity, among others. This paper describes the preparation of polymeric solid acid based on the chemical modification of poly (1-fenietileno) (PS) and Poly (1-chloroethylene) (PVC) by the introduction of sulfonic acid groups and the application of these polymers as catalysts in the esterification reaction of oleic acid with methanol. The modified materials were characterized by Infrared Spectroscopy, Elemental Analysis and titration acid-base of the acid groups. All techniques confirmed the chemical changes and the presence of sulfur associated with sulfonic acid groups or sulfates. The modified polymers excellent performance in the esterification reaction of oleic acid with methanol a degree of conversion higher than 90% for all investigated polymers (modified PS and PVC (5% w / w)), with a mass ratio of oleic acid: methanol 1:10 to 100 ° C. The best performance was observed for the modified PVC catalyst (PVCS) which showed low degree of swelling during the reactions is recovered by filtration different from that observed for polystyrene sulfonate (PSS). Given these facts, the PVCS was employed as a catalyst in the esterification reaction of oleic acid in different times and different temperatures to obtain the kinetic parameters of the reaction. Experimental data show a great fit for pseudo-homogeneous model of second order and activation energy value of 41.12 kJ mol -1, below that found in the literature for the uncatalyzed reaction, 68.65 kJ mol -1 .The PVCS exhibits good catalytic activity for 3 times of reuse, with a slight decrease in the third cycle, but with a conversion of about 78%. The results show that solid polymeric acid has good chemical stability for the application in esterification reaction of commercial importance with possible application in the biodiesel production. The advantages in use of this system are the increased reaction rate at about 150 times, at these test conditions, the replacement of sulfuric acid as a catalyst for this being the most corrosive and the possibility of reuse of the polymer for several cycles.

Health-promoting properties of bioactive peptides derived from milk proteins in infant food : a review

Peer reviewed

Iron assimilation by the clam Laternula elliptica from Potter Cove, King Georg Island, Antarctica

Iron stable isotope signatures (d56Fe) in hemolymph (bivalve blood) of the Antarctic bivalve Laternula elliptica were analyzed by Multiple Collector-Inductively Coupled Plasma-Mass Spectrometry (MC-ICP-MS) to test whether the isotopic fingerprint can be tracked back to the predominant sources of the assimilated Fe. An earlier investigation of Fe concentrations in L. elliptica hemolymph suggested that an assimilation of reactive and bioavailable Fe (oxyhydr)oxide particles (i.e. ferrihydrite), precipitated from pore water Fe around the benthic boundary, is responsible for the high Fe concentration in L. elliptica (Poigner et al., 2013, doi:10.1016/j.ecss.2013.10.027). At two stations in Potter Cove (King George Island, Antarctica) bivalve hemolymph showed mean d56Fe values of -1.19 ± 0.34 per mil and -1.04 ± 0.39 per mil, respectively, which is between 0.5 per mil and 0.85 per mil lighter than the pool of easily reducible Fe (oxyhydr)oxides of the surface sediments (-0.3 per mil to -0.6 per mil). This is in agreement with the enrichment of lighter Fe isotopes at higher trophic levels, resulting from the preferential assimilation of light isotopes from nutrition. Nevertheless, d56Fe hemolymph values from both stations showed a high variability, ranging between -0.21 per mil (value close to unaltered/primary Fe(oxyhydr)oxide minerals) and -1.91 per mil (typical for pore water Fe or diagenetic Fe precipitates), which we interpret as a "mixed" d56Fe signature caused by Fe assimilation from different sources with varying Fe contents and d56Fe values. Furthermore, mass dependent Fe fractionation related to physiological processes within the bivalve cannot be ruled out. This is the first study addressing the potential of Fe isotopes for tracing back food sources of bivalves.

Microwave Synthesis of Short-Chained Fluorinated Ionic Liquids and Their Surface Properties

Microwave synthesis is shown to be a valuable route to novel fluorinated ionic liquid surfactants. 1-Methyl-3-(3,3,4,4,5,5,6,6,6-nonafluorohexyl)imidazolium iodide was prepared by treatment of 1-methylimidazole with 1-iodo-1H,1H,2H,2H-perfluorohexane in a microwave reactor, and this product underwent anion exchange to yield 1-methyl-3-(3,3,4,4,5,5,6,6,6-nonafluorohexyl)imidazolium nonafluoro-1-butanesulfonate. This catanionic surfactant showed intriguing phase behavior and low surface tension.

Isolation and structural characterization of fucoidans from the brown algae Fucus vesiculosus

agricultural, pharmaceutical, cosmetic or bioenergy applications. They contain bioactive compounds, namely, polysaccharides Fucoidan. These polysaccharides are mainly constituted by fucose residues and sulfate esters, and have been reported to possess a broad variety of bioactivities, such as anticoagulant, anti-thrombotic, anti-inflammatory, anti-tumor, antiviral and antioxidant. In this work, the fucoidans from brown seaweed Fucus vesiculosus from “Ria de Aveiro” were isolated and characterized in order to add value to this natural resource of the region. The polysaccharides from the algae were extracted with hot water and fractioned by ethanol precipitation and calcium chloride salts. They were further purified by using anion-exchange chromatography, allowing to separate the neutral polysaccharides (laminaranas) from those negatively charged (sulfated fucoidans and alginate). The purified polysaccharides showed high content of fucose (41 mol%) and sulfates (50 mol%), having also galactose residues (6 mol%), which confirm the presence of only sulfated fucoidans. Glycosidic linkages analysis show the presence of high amounts of terminal fucose (25%) and (1→3,4)-Fuc (26%), allowing to infer that the fucoidans were highly branched. These fucoidans are composed also by (1→2)-Fuc (14%) and (1→3)-Fuc linkages (10-16%). In this work it was also tested an alternative extraction technology, the microwave hydrodiffusion and gravity system, where it was possible to extract sugars, although in low yields. However, this methodology allowed to extract polysaccharides, constituted mainly by fucose and uronic acids, as well as mannitol, without the need to add any solvent, obtaining at the end the dry alga. The current work allowed to characterize the structure of the fucoidans isolated from “Ria de Aveiro” F. vesiculosus. The presence of high content of sulfate residues and the high branch degree of the purified fucoidans allow to infer that these polysaccharides could have potential to be studied for biomedical applications, according to their biological activities.

Isomérisation du lactose en lactulose en solution modèle de lactose et dans du perméat de lactosérum par électro-activation supportée par échange ionique sur résine

L’isomérisation alcaline du lactose en lactulose a été effectuée électro-chimiquement à l’aide d’un réacteur d’électro-activation en combinaison avec des résines échangeuses d’anions de polystyrène de trois types; à savoir Lewatit VP-OC-1065 faible-acide, Lewatit MP-64 moyenne-acide et Lewatit Monoplus M500 forte-acide. Les paramètres opératoires qui ont fait l’objet de cette étude ont été étudiés sur trois blocs expérimentaux pour optimiser le système. Dans le Premier bloc, les paramètres étudiés sont : (1) ratio lactose-5%(p/v) : résine échangeuse d’anions (1:0.5, 1:1 et 1:2), (2) intensité du champ électrique : 50 mA, 100 mA et 200 mA et (3) type de résines : faible, moyenne et forte. Dans le Deuxième bloc, les paramètres mis à l’étude comprenaient : (1) l’intensité du champ électrique : 300 mA, 450 mA et 550 mA, (2) le débit de la solution traitée : 25 ml / min, 50 ml/ min et 100 ml/min et (3) la surface active de la membrane adjacente au compartiment cathodique : 0.78 cm2, 7.06 cm2 et 18.1 cm2. Le Troisième bloc expérimental a été effectué sur la base de la distance entre la membrane et l’électrode : 3.1 cm, 5.6 cm et 9 cm. Le même modèle expérimental a était également réalisé avec du perméat du lactosérum d’une concentration de 7% (p/v). Les résultats obtenus ont révélé que le meilleur rendement de l’isomérisation du lactose en lactulose était obtenu après 30 minutes d’électroactivation en utilisant une solution modèle de lactose-5% avec une valeur d’environ 20.1%. Les conditions opératoires qui ont permis d’avoir ce taux de conversion sont une intensité du courant de 550 mA, un débit de la solution de 25 ml/min, une surface active de la membrane de 7.06 cm2 et une distance de 9 cm entre la cathode et la membrane qui lui y est adjacente. En utilisant le perméat de lactosérum-7%, un taux de conversion de lactose en lactulose de 8.34% a était obtenu avec une intensité du courant de 200 mA, un débit de 120 ml/min, une surface active de de 18.1cm2 et une distance de 9 cm entre la membrane et l’électrode dans le compartiment cathodique. Les analyses de variance ont indiqué un effet catalytique significatif du type de la résine. En effet, la résine-forte a permis d’avoir les plus hauts rendements de la réaction d’isomérisation par électro-activation. La résistance électrique globale du système d’électroactivation dépendait de la valeur de l’intensité du courant. Le produit final était d’une grande pureté, car il ne présentait que quelques traces de galactose (< 4%).