Synthesis and evaluation of lipophilic BTBP ligands for An/Ln separation in nuclear waste treatment: the effect of alkyl substitution on extraction properties and implications for ligand design

Four new 6,6′-bis(1,2,4-triazin-3-yl)-2,2′-bipyridine (BTBP) ligands, which contain either additional alkyl groups on the pyridine rings or seven-membered aliphatic rings attached to the triazine rings, have been synthesized, and the effects of the additional alkyl substitution in the 4- and 4′-positions of the pyridine rings on their extraction properties with LnIII and AnIII cations in simulated nuclear waste solutions have been studied. The speciation of ligand 13 with some trivalent lanthanide nitrates was elucidated by 1H NMR spectroscopic titrations and ESI-MS. Although 13 formed both 1:1 and 1:2 complexes with LaIII and YIII, only 1:2 complexes were observed with EuIII and CeIII. Quite unexpectedly, both alkyl-substituted ligands 12 and 13 showed lower solubilities in certain diluents than the unsubstituted ligand CyMe4-BTBP. Compared to CyMe4-BTBP, alkyl-substitution was found to decrease the rates of metal-ion extraction of the ligands in both 1-octanol and cyclohexanone. A highly efficient (DAm > 10) and selective (SFAm/Eu > 90) extraction was observed for 12 and 13 in cyclohexanone and for 13 in 1-octanol in the presence of a phase-transfer agent. The implications of these results for the design of improved extractants for radioactive waste treatment are discussed.

Corynebacterium uterequi sp. nov., a non-lipophilic bacterium isolated from urogenital samples from horses

Three strains of a Gram-positive, catalase-positive, fermentative, non-lipophilic, previously unknown bacterium were isolated from urogenital samples taken from mares in Scotland (M401624/00/1) and Sweden (VM 2074 and VM 2298T). All were deposited with the CCUG with tentative identifications as Corynebacterium spp. The strains were characterized using a polyphasic taxonomic approach. Biochemically, the strains were very similar to each other, but phylogenetically distinct from Corynebacterium species with validly published names (≤95% sequence similarity). rpoB gene sequence data confirmed the strains belonged to the same species (>99% sequence similarity) and were distinct from species with validly published names (>13% sequence divergence). On the basis of phenotypic and sequence data, the strains represent a novel species within the genus Corynebacterium, for which the name Corynebacterium uterequi is proposed. The type strain is VM 2298T (=CCUG 61235T = DSM 45634T), isolated from equine uterus.

Polymorphism, crystallinity and hydrophilic-lipophilic balance of stearic acid and stearic acid-capric/caprylic triglyceride matrices for production of stable nanoparticles

There is an increasing interest in lipid nanoparticles because of their suitability for several administration routes. Thus, it becomes even more relevant the physicochemical characterization of lipid materials with respect to their polymorphism, lipid miscibility and stability, as well as the assessment of the effect of surfactant on the type and structure of these nanoparticles. This work focuses on the physicochemical characterization of lipid matrices composed of pure stearic acid or of mixtures of stearic acid-capric/caprylic triglycerides, for drug delivery. The lipids were analyzed by Differential Scanning Calorimetry (DSC), Wide Angle X-ray Diffraction (WAXD), Polarized Light Microscopy (PLM) and hydrophilic-lipophilic balance (HLB) in combination with selected surfactants to determine the best solid-to-liquid ratio. Based on the results obtained by DSC and WAXD, the selected qualitative and quantitative composition contributed for the production of stable nanoparticles, since the melting and the tempering processes provided important information on the thermodynamic stability of solid lipid matrices. The best HLB value obtained for stearic acid-capric/caprylic triglycerides was 13.8, achieved after combining these lipids with accepted surfactants (trioleate sorbitan and polysorbate 80 in the ratio of 10:90). The proposed combinations were shown useful to obtain a stable emulsion to be used as intermediate form for the production of lipid nanoparticles. (C) 2011 Elsevier B.V. All rights reserved.

Properties of lipophilic nucleoside monolayers at the air-water interface

The capability of self-assembly and molecular recognition of biomolecules is essential for many nanotechnological applications, as in the use of alkyl-modified nucleosides and oligonucleotides to increase the cellular uptake of DNA and RNA. In this study, we show that a lipophilic nucleoside, which is an isomer mixture of 2`-palmitoyluridin und 3`-palmitoyluridin, forms Langmuir monolayers and Langmuir-Blodgett films as a typical amphiphile, though with a smaller elasticity. The nucleoside may be incorporated into dipalmitoyl phosphatidyl choline (DPPC) monolayers that serve as a simplified cell membrane model. The molecular-level interactions between the nucleoside and DPPC led to a remarkable condensation of the mixed monolayer, which affected both surface pressure and surface potential isotherms. The morphology of the mixed monolayers was dominated by the small domains of the nucleoside. The mixed monolayers could be deposited onto solid substrates as a one-layer Langmuir Blodgett film that displayed UV-vis absorption spectra typical of aggregated nucleosides owing to the interaction between the nucleoside and DPPC. The formation of solid films with DNA building blocks in the polar heads may open the way for devices and sensors be produced to exploit their molecular recognition properties. (C) 2010 Elsevier B.V. All rights reserved.

The isatin-Schiff base copper(II) complex Cu(isaepy)(2) acts as delocalized lipophilic cation, yields widespread mitochondrial oxidative damage and induces AMP-activated protein kinase-dependent apoptosis

We previously demonstrated that Bis[(2-oxindol-3-ylimino)-2-(2-aminoethyl) pyridine-N, N`] copper(II) [Cu(isaepy)(2)] was an efficient inducer of the apoptotic mitochondrial pathway. Here, we deeply dissect the mechanisms underlying the ability of Cu(isaepy)(2) to cause mitochondriotoxicity. In particular, we demonstrate that Cu(isaepy)(2) increases NADH-dependent oxygen consumption of isolated mitochondria and that this phenomenon is associated with oxy-radical production and insensitive to adenosine diphosphate. These data indicate that Cu(isaepy)(2) behaves as an uncoupler and this property is also confirmed in cell systems. Particularly, SH-SY5Y cells show: (i) an early loss of mitochondrial transmembrane potential; (ii) a decrease in the expression levels of respiratory complex components and (iii) a significant adenosine triphosphate (ATP) decrement. The causative energetic impairment mediated by Cu(isaepy)(2) in apoptosis is confirmed by experiments carried out with rho(0) cells, or by glucose supplementation, where cell death is significantly inhibited. Moreover, gastric and cervix carcinoma AGS and HeLa cells, which rely most of their ATP production on oxidative phosphorylation, show a marked sensitivity toward Cu(isaepy)(2). Adenosine monophosphate-activated protein kinase (AMPK), which is activated by events increasing the adenosine monophosphate: ATP ratio, is deeply involved in the apoptotic process because the overexpression of its dominant/negative form completely abolishes cell death. Upon glucose supplementation, AMPK is not activated, confirming its role as fuel-sensing enzyme that positively responds to Cu(isaepy)(2)-mediated energetic impairment by committing cells to apoptosis. Overall, data obtained indicate that Cu(isaepy)(2) behaves as delocalized lipophilic cation and induces mitochondrial-sited reactive oxygen species production. This event results in mitochondrial dysfunction and ATP decrease, which in turn triggers AMPK-dependent apoptosis.

Determination of lipophilic and hydrophilic antioxidants in Solanum Lycopersicum L. tomato from Gordal variety by LL-USAE combined with UHPLC-PDA/FLR

Tomato (Lycopersicon esculentum L.) is one of the main constituents of the Mediterranean diet. Its consumption has been proposed to reduce the risk of cardiovascular diseases and certain types of cancer. It is therefore one of the most popular and extensively consumed vegetable crop worldwide. To gain insights on the potential of Lycopersicon esculentum L. as bioactive food, two analytical methodologies were developed to determine the levels of the lipophilic -tocopherol, α-tocopherol, β-carotene, lycopene; and hydrophilic antioxidants ascorbic acid. The quantification of total carotenoids (β-carotene and lycopene) was assessed through a liquid–liquid ultrasound assisted extraction (LL-USAE) in combination with ultraviolet-visible spectroscopy (UV-Vis), according to method of mean, for total carotenoids (λmáx = 450 nm. The ultra-high performance liquid chromatographic using both photodiode array and fluorescence detection (UHPLC-PDA/FLR), allows the identification and quantification of the target lipophilic and hydrophilic antioxidants. This methodology UHPLC-PDA/FLR is fast, simple and revealed a high sensitivity for the compounds under study. The limits of detection (LODs) and quantification (LOQs) obtained were much lower (about 10 times) than the reported in literature. The method LL-USAE/UV-Vis was validated and applied to different tomato foodstuffs. The results reveal a small increase of carotenoids content during maturation, reaching the maximum level when ripe. These results complement those obtained by the ORAC and TBARS assays that show an increase of antioxidant capacity during maturation. The LODs ans LOQs obtained were also about 10 times lower than reported in literature. The carotenoid content was also evaluated by LL-USAE/UV-Vis in different tomatoes varieties. Regional variety present the high carotenoid level, followed by campari and gordal, and at last grape. This methodology was also applied to different processed food samples containing tomatoes derivatives. Highest carotenoids content were obtained in concentrated tomato foodstuffs.

Influence of the Lipophilic External Phase Composition on the Preparation and Characterization of Xylan Microcapsules-A Technical Note

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Electrochemical evaluation of lipophilic antioxidants from Iryanthera juruensis fruits (Myristicaceae)

Testes em placas de CCDC reveladas com solução de beta-caroteno mostraram a presença de duas substâncias com propriedades antioxidantes no extrato hexânico. Elas foram isoladas e identificadas como 3-metil-sargacromenol (1) and sargacromenol (2). O extrato hexânico forneceu ainda o ácido 3-metil-sargaquinóico (3) e o ácido sargaquinóico (4). O comportamento eletroquímico destas substâncias foi investigado em CH2Cl2/Bu4NBF4 sobre eletrodo de carbono vítreo. A oxidação do grupo fenólico nos tocotrienóis 1 and 2 é responsável por um pico anódico em potenciais de +0.23V e +0.32V, os quais são correlacionados com sua atividade antioxidante. O mecanismo de oxidação é comparado com o comportamento eletroquímico do antioxidante alfa-tocopherol.

RELATIONSHIP AMONG EXTRACTIVES, LIGNIN AND HOLOCELLULOSE CONTENTS WITH PERFORMANCE INDEX OF SEVEN WOOD SPECIES USED FOR BOWS OF STRING INSTRUMENTS

In this paper we investigate the influence of extractives, lignin and holocellulose contents on performance index (PI) of seven woods used or tested for violin bows. Woods with higher values of this index (PI = root MOE/rho, where MOE is modulus of elasticity and rho is density) have a higher bending stiffness at a given mass, which can be related to bow wood quality. Extractive content was negatively correlated with PI in Caesalpinia echinata, Hanclroanthus sp. and Astronium lecointei. In C. echinata holocellulose was positively correlated with PI. These results need to be further explored with more samples and by testing additional wood properties. Although the chemical constituents could provide an indication of quality, it is not possible to establish appropriate woods for bows solely by examining their chemical constituents.

Synthesis and Supramolecular Architectures of Lipophilic Derivatives of Guanine

Self-assembly relies on the association of pre-programmed building blocks through non-covalent interactions to give complex supramolecular architectures. Previous studies provided evidence for the unique self-assembly properties of semi-synthetic lipophilic guanosine derivatives which can sequestrate ions from an aqueous phase, carry them into an organic phase where they promote the generation of well-defined supramolecular assemblies. In the presence of cations lipophilic guanosines form columnar aggregates while in their absence they generate supramolecular ribbons. The aim of this thesis has been the synthesis of guanine derivatives, in particular N9-alkylated guanines and a guanosine functionalized as a perchlorotriphenylmetil moiety (Gace-a-HPTM) in order to observe their supramolecular behaviour in the absence of sugar (ribose or deoxyribose) and in the presence of a bulky and chiral substituent respectively. By using guanine instead of guanosine, while maintaining all the hydrogen bond acceptor and donor groups required for supramolecular aggregation, the steric hindrance to supramolecular aggregation is notably reduced because (i.e. guanines with groups in N9 different from sugar are expected to have a greatest conformational freedom even in presence of bulky groups in C8). Supramolecular self-assembly of these derivatives has been accomplished in solutions by NMR and CD spectroscopy and on surface by STM technique. In analogy with other guanosine derivatives, also N9-substituted guanines and GAceHPTM form either ribbon-like aggregates or cation-templated G-quartet based columnar structures.

Lipophilic nucleosides: studies toward self-assembled functional materials

Molecular self-assembly takes advantage of supramolecular non-covalent interactions (ionic, hydrophobic, van der Waals, hydrogen and coordination bonds) for the construction of organized and tunable systems. In this field, lipophilic guanosines can represent powerful building blocks thanks to their aggregation proprieties in organic solvents, which can be controlled by addition or removal of cations. For example, potassium ion can template the formation of piled G-quartets structures, while in its absence ribbon-like G aggregates are generated in solution. In this thesis we explored the possibility of using guanosines as scaffolds to direct the construction of ordered and self-assembled architectures, one of the main goals of bottom-up approach in nanotechnology. In Chapter III we will describe Langmuir-Blodgett films obtained from guanosines and other lipophilic nucleosides, revealing the “special” behavior of guanine in comparison with the other nucleobases. In Chapter IV we will report the synthesis of several thiophene-functionalized guanosines and the studies towards their possible use in organic electronics: the pre-programmed organization of terthiophene residues in ribbon aggregates could allow charge conduction through π-π stacked oligothiophene functionalities. The construction and the behavior of some simple electronic nanodevices based on these organized thiopehene-guanosine hybrids has been explored.

Post-mortem angiography after vascular perfusion with diesel oil and a lipophilic contrast agent

OBJECTIVE: The objective of our study was to establish optimal perfusion conditions for high-resolution postmortem angiography that would permit dynamic visualization of the arterial and venous systems. MATERIALS AND METHODS: Cadavers of two dogs and one cat were perfused with diesel oil through a peristaltic pump. The lipophilic contrast agent Lipiodol Ultra Fluide was then injected, and angiography was performed. The efficiency of perfusion was evaluated in the chick chorioallantoic membrane. RESULTS: Vessels could be seen up to the level of the smaller supplying and draining vessels. Hence, both the arterial and the venous sides of the vascular system could be distinguished. The chorioallantoic membrane assay revealed that diesel oil enters microvessels up to 50 microm in diameter and that it does not penetrate the capillary network. CONCLUSION: After establishing a postmortem circulation by diesel oil perfusion, angiography can be performed by injection of Lipiodol Ultra Fluide. The resolution of the images obtained up to 3 days after death is comparable to that achieved in clinical angiography.

Effects of Lipophilic Extract of Viscum album L. and Oleanolic Acid on Migratory Activity of NIH/3T3 Fibroblasts and on HaCat Keratinocytes

Viscum album L. lipophilic extract (VALE) contains pharmacologically active pentacyclic triterpenes that are known to exhibit immunomodulatory, antitumor, and wound healing activity. Preliminary clinical observations indicate that VALE was able to influence cutaneous wound healing in vivo. The objective of this study was to investigate wound closure related properties of VALE in vitro. As measured in a wound healing assay, VALE and its predominant triterpene oleanolic acid (OA) significantly and dose dependently promoted the migration of NIH/3T3 fibroblasts in vitro, thereby leading to an enhanced wound closure. Compared to the negative control, maximal stimulation by 26.1% and 26.2%, respectively, was attained with 10 μg/mL VALE and 1 μg/mL OA. Stimulation of proliferation in NIH/3T3 fibroblasts by VALE and OA could be excluded. At higher concentrations both substances affected proliferation and viability of NIH/3T3 fibroblasts and HaCat keratinocytes. In the toxic range of concentrations of VALE and OA, migration of NIH/3T3 fibroblasts was suppressed. The extent of the stimulatory effect on cell migration of VALE quite closely corresponded to the effect expected by the concentrations of OA contained in the crude extract VALE. These data support the casual observation that Viscum album L. lipophilic extract might modulate wound healing related processes in vivo.

Targeting peptide nucleic acid (PNA) oligomers to mitochondria within cells by conjugation to lipophilic cations: implications for mitochondrial DNA replication, expression and disease

The selective manipulation of mitochondrial DNA (mtDNA) replication and expression within mammalian cells has proven difficult. One promising approach is to use peptide nucleic acid (PNA) oligomers, nucleic acid analogues that bind selectively to complementary DNA or RNA sequences inhibiting replication and translation. However, the potential of PNAs is restricted by the difficulties of delivering them to mitochondria within cells. To overcome this problem we conjugated a PNA 11mer to a lipophilic phosphonium cation. Such cations are taken up by mitochondria through the lipid bilayer driven by the membrane potential across the inner membrane. As anticipated, phosphonium–PNA (ph–PNA) conjugates of 3.4–4 kDa were imported into both isolated mitochondria and mitochondria within human cells in culture. This was confirmed by using an ion-selective electrode to measure uptake of the ph–PNA conjugates; by cell fractionation in conjunction with immunoblotting; by confocal microscopy; by immunogold-electron microscopy; and by crosslinking ph–PNA conjugates to mitochondrial matrix proteins. In all cases dissipating the mitochondrial membrane potential with an uncoupler prevented ph–PNA uptake. The ph–PNA conjugate selectively inhibited the in vitro replication of DNA containing the A8344G point mutation that causes the human mtDNA disease ‘myoclonic epilepsy and ragged red fibres’ (MERRF) but not the wild-type sequence that differs at a single nucleotide position. Therefore these modified PNA oligomers retain their selective binding to DNA and the lipophilic cation delivers them to mitochondria within cells. When MERRF cells were incubated with the ph–PNA conjugate the ratio of MERRF to wild-type mtDNA was unaffected, even though the ph–PNA content of the mitochondria was sufficient to inhibit MERRF mtDNA replication in a cell-free system. This unexpected finding suggests that nucleic acid derivatives cannot bind their complementary sequences during mtDNA replication. In summary, we have developed a new strategy for targeting PNA oligomers to mitochondria and used it to determine the effects of PNA on mutated mtDNA replication in cells. This work presents new approaches for the manipulation of mtDNA replication and expression, and will assist in the development of therapies for mtDNA diseases.

Polycationic lipophilic-core dendrons as penetration enhancers for the oral administration of low molecular weight heparin

Two polycationic lipophilic-core carbohydrate-based dendrons 2a-b and five polycationic lipophilic-core peptide dendrons 3-6, containing four arginine or lysine terminal residues, were synthesized and then tested in rats as penetration enhancers for the oral delivery of low molecular weight heparin. Better results were obtained with dendrons containing terminal lysine residues than terminal arginine. A significant anti-factor Xa activity was obtained when low molecular weight heparin was coadministered with dendron 5. (c) 2005 Elsevier Ltd. All rights reserved.