Hybrid nanofibrous yarns based on N-carboxyethylchitosan and silver nanoparticles with antibacterial activity prepared by self-bundling electrospinning

Hybrid nanofibrous materials with antibacterial activity consisting of yarns from N-carboxyethylchitosan (CECh) and poly(ethylene oxide) (PEO) that contain 5 wt % or 10 wt % silver nanoparticles (AgNPs) were prepared. This was achieved by electrospinning using formic acid as a solvent and as a reducing agent for silver ions. AgNO₃ was used as an Ag⁺-containing salt. Its concentration was selected to be 0.02 mol/L or 0.04 mol/L in order the content of the AgNPs in the electrospun nanofibers to be 5 wt % or 10 wt %, respectively. The self-bundling of the fibers into yarns with a mean diameter of ca. 35 μm was enabled only by using a grounded needle electrode. The reduction of the silver ions to an elemental silver was evidenced by UV-vis spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The transmission electron microscopy (TEM) analyses revealed that AgNPs formed at AgNO₃ concentration of 0.02 mol/L were with a mean diameter of 4 ± 0.5 nm and were distributed uniformly within the fiber. The increase of AgNO₃ concentration to 0.04 mol/L led to the preparation of AgNPs with a higher mean diameter and a broader diameter distribution as well as to aggregate formation. The performed studies on the antibacterial activity of CECh/PEO/AgNPs fibrous materials against Staphylococcus aureus showed that at AgNPs content of 5 wt % the mats had bacteriostatic, and at AgNPs content of 10 wt %—bactericidal activity.     

Micelle formation in the presence of photosystem I

The correlation between membrane protein solubilisation and detergent aggregation in aqueous solution is studied for a series of n-alkyl-β-d-maltosides (C_xG₂ with x = 10, 11, 12 being the number of carbon atoms in the alkyl chain) using the trimeric photosystem I core complex (PSIcc) of oxygenic photosynthesis from Thermosynechococcus elongatus as model protein. While protein solubilisation is monitored via the turbidity of the solution, the aggregation behavior of the detergent is probed via the fluorescence spectrum of the polycyclic aromatic hydrocarbon pyrene. In addition, changes of the fluorescence spectrum of PSIcc in response to formation of the detergent belt surrounding its hydrophobic surface are investigated. Solubilisation of PSIcc and aggregation of detergent into micelles or belts are found to be strictly correlated. Both processes are complete at the critical solubilisation concentration (CSC) of the detergent, at which the belts are formed. The CSC depends on the concentration of the membrane protein, [prot], and is related to the critical micelle concentration (CMC) by the empirical law ln(CSC/CMC) = n¯₀ [prot], where the constant n¯₀ = (2.0 ± 0.3) μM⁻¹ is independent of the alkyl chain length x. Formation of protein-free micelles below the CSC is not observed even for x = 10, where a significant excess of detergent is present at the CSC. This finding indicates an influence of PSIcc on micelle formation that is independent of the binding of detergent to the hydrophobic protein surface. The role of the CSC in the optimisation of membrane protein crystallisation is discussed.     

Acylated flavonol tetraglycosides from Delphinium gracile

An ethanol extract of the aerial parts of Delphinium gracile DC. yielded five flavonol glycosides quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(E-p-caffeoyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (1), quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (2), quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(Z-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (3), kaempferol-3-O-{[β-d-glucopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranoside-7-O-(4-O-acetyl)-α-l-rhamnopyranoside (4) kaempferol-3-O-{[β-d-glucopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranoside-7-O-(4-O-acetyl)-α-l-rhamnopyranoside (5) in addition to 4-(β-d-glucopyranosyloxy)-6-methyl-2H-pyran-2-one (6) and rutin. Structures were elucidated by spectroscopic methods.     

Bioactive saponins from Microsechium helleri and Sicyos bulbosus

Eleven oleanane-type saponins (1-11) have been isolated from Microsechium helleri and Sicyos bulbosus roots and were evaluated for their antifeedant, nematicidal and phytotoxic activities. Saponins {3-O-β-d-glucopyranosyl (1 → 3)-β-d-glucopyranosyl-2β,3β,16α,23-tetrahydroxyolean-12-en-28-oic acid 28-O-α-l-rhamnopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-[β-d-xylopyranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranoside} (1), and {3-O-β-d-glucopyranosyl-2β,3β,16α,23-tetrahydroxyolean-12-en-28-oic acid 28-O-α-l-rhamnopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-[β-d-xylopyranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranoside} (2) were also isolated from M. helleri roots together with the two known compounds 3 and 4. Seven known structurally related saponins (5-11) were isolated from S. bulbosus roots. The structures of these compounds were established as bayogenin and polygalacic glycosides using one- and two-dimensional NMR spectroscopy and mass spectrometry. Compounds 7, 10, bayogenin (12) and polygalacic acid (13) showed significant (p < 0.05) postingestive effects on Spodoptera littoralis larvae, compounds 5-11 and 12 showed variable nematicidal effects on Meloydogyne javanica and all tested saponins had variable phytotoxic effects on several plant species (Lycopersicum esculentum, Lolium perenne and Lactuca sativa). These are promising results in the search for natural pesticides from the Cucurbitaceae family.     

Copper(II) complexes with 2-N-(picolinylidene)-n-R-phenols: Solvatochromism, self-assembly and supramolecular structures

A series of copper(II) complexes having the formula [Cu(n-R-pyp)X] with the N,N,O-donor Schiff base system 2-N-(picolinylidene)-n-R-phenol (n-R-Hpyp) (where n = 3, 4, 5 and 6, when R = Me and n = 4 when R = Cl) and halide (X⁻ = Cl⁻ or Br⁻) as an ancillary ligand have been synthesized. The complexes are characterized by microanalytical, magnetic and various spectroscopic measurements. They display solvatochromic behavior. Single crystal X-ray structures of all the complexes are determined. In coordinatively unsaturated species such as a square-planar complex, the metal ion can interact with a fifth atom and if this atom is metal bound, dimeric or polymeric aggregate is formed. In the present series of complexes, the metal ions are square-planar and distorted square-pyramidal when there is an intermolecular Cu···X interaction. In addition to this Cu···X interaction, presence of intermolecular weak non-covalent interactions namely O-H···O, C-H···O, C-H···X and π···π are perceived. The supramolecular architectures formed by the molecules of these complexes via these interactions are scrutinized. The observed supramolecular structural motifs can be classified as staircase, ladder, brick-wall and square-grid. Except for R = Cl the analogous chloride and bromide coordinated complexes show similar structural features.     

Acylated triterpene saponins from the roots of Securidaca longepedunculata

Four triterpene saponins, 3-O-β-d-glucopyranosylpresenegenin 28-O-β-d-apiofuranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-[β-d-apiofuranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-{4-O-[(E)-3,4,5-trimethoxycinnamoyl]}-β-d-fucopyranosyl ester, 3-O-β-d-glucopyranosylpresenegenin 28-O-β-d-apiofuranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-[β-d-apiofuranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-[(6-O-acetyl)-β-d-glucopyranosyl-(1 → 3)]-{4-O-[(E)-3,4,5-trimethoxycinnamoyl]}-β-d-fucopyranosyl ester, 3-O-β-d-glucopyranosylpresenegenin 28-O-β-d-apiofuranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-[β-d-apiofuranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-[β-d-galactopyranosyl-(1 → 3)]-{4-O-[(E)-3,4,5-trimethoxycinnamoyl]}-β-d-fucopyranosyl ester, and 3-O-β-d-glucopyranosylpresenegenin 28-O-β-d-apiofuranosyl-(1 → 3)-[α-l-arabinopyranosyl-(1 → 4)]-β-d-xylopyranosyl-(1 → 4)-[β-d-apiofuranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-{4-O-[(E)-3,4,5-trimethoxycinnamoyl]}-β-d-fucopyranosyl ester, were isolated from the roots of Securidaca longepedunculata, together with three known compounds. Their structures were established mainly by 2D NMR techniques and mass spectrometry.     

Steroidal saponins from the leaves of Beaucarnea recurvata

Thirteen steroidal saponins were isolated from the leaves of Beaucarnea recurvata Lem. Their structures were established using one- and two-dimensional NMR spectroscopy and mass spectrometry. Six of them were identified as: 26-O-β-d-glucopyranosyl (25S)-furosta-5,20(22)-diene 1β,3β,26-triol 1-O-α-l-rhamnopyranosyl-(1 → 2) β-d-fucopyranoside, 26-O-β-d-glucopyranosyl (25S)-furosta-5,20(22)-diene 1β,3β,26-triol 1-O-α-l-rhamnopyranosyl-(1 → 2)-4-O-acetyl-β-d-fucopyranoside, 26-O-β-d-glucopyranosyl (25R)-furosta-5,20(22)-diene-23-one-1β,3β,26-triol 1-O-α-l-rhamnopyranosyl-(1 → 2) β-d-fucopyranoside, 26-O-β-d-glucopyranosyl (25S)-furosta-5-ene-1β,3β,22α,26-tetrol 1-O-α-l-rhamnopyranosyl-(1 → 4)-6-O-acetyl-β-d-glucopyranoside, 26-O-β-d-glucopyranosyl (25S)-furosta-5-ene-1β,3β,22α,26-tetrol 1-O-α-l-rhamnopyranosyl-(1 → 2) β-d-fucopyranoside, and 24-O-β-d-glucopyranosyl (25R)-spirost-5-ene-1β,3β,24-triol 1-O-α-l-rhamnopyranosyl-(1 → 2)-4-O-acetyl-β-d-fucopyranoside. The chemotaxonomic classification of B. recurvata in the family Ruscaceae was discussed.     

The physicochemical properties and chemical composition of trehalose lipids produced by Rhodococcus erythropolis 51T7

This study analyzed the chemical and physical properties of a biosurfactant synthesized by Rhodococcus sp. 51T7. The biosurfactant was a trehalose tetraester (THL) consisting of six components: one major and five minor. The hydrophobic moieties ranged in size from 9 to 11 carbons. The critical micelle concentration (CMC) was 0.037 g L⁻¹ and the interfacial tension against hexadecane was 5 mN m⁻¹. At pH 7.4 the glycolipid CMC/critical aggregation concentration (CAC) was 0.05 g L⁻¹ and at pH 4 it was 0.034 g L⁻¹. A phase diagram revealed effective emulsification with water and paraffin or isopropyl myristate. A composition of 11.3-7.5-81.8 (isopropyl myristate-THL-W) was stable for at least 3 months. The HLB was 11 and the phase behaviour of the glycolipid revealed the formation of lamellar and hexagonal liquid-crystalline textures.     

FCS study of the thermodynamics of membrane protein insertion into the lipid bilayer chaperoned by fluorinated surfactants

Experimental determination of the free energy (ΔG) stabilizing the structure of membrane proteins (MPs) in their native environment has been hampered by the aggregation and precipitation of MPs outside the lipid bilayer. We recently demonstrated that the latter process can be prevented by the use of fluorinated surfactants, FTACs, that act as chaperones for MP insertion without partitioning in the membrane themselves. Here we combine the advantages of the chaperone-like ability of FTACs with the sensitivity of fluorescence correlation spectroscopy measurements to determine ΔG of bilayer insertion of model MPs. First, we calibrate our approach by examining the effects of chaperoned insertion on ΔG of transmembrane insertion of Annexin B12. We find that a shorter-chained surfactant, FTAC-C6, for which the working concentration range of 0.05-0.2 mM falls below CMC = 0.33 mM, has a mild effect on an apparent ΔG. In contrast, additions of a longer-chained FTAC-C8 (CMC = 0.03 mM) result in a steep and nonlinear concentration dependence of ΔG. We then apply the same methodology to the pH-triggered insertion of diphtheria toxin T-domain, which is known to be affected by nonproductive aggregation in solution. We find that the correction of the ΔG value needed to compensate for unchaperoned insertion of the T-domain exceeds 3 kcal/mole. A relatively shallow and linear dependence of the ΔG for Annexin B12 and T-domain insertion on FTAC-C6 concentration is encouraging for future applications of this surfactant in thermodynamic studies of the stability of other MPs.     

Triterpenoid saponins from a cytotoxic root extract of Sideroxylonfoetidissimum subsp. gaumeri

Evaluation of the cytotoxicity of an ethanolic root extract of Sideroxylonfoetidissimum subsp. gaumeri (Sapotaceae) revealed activity against the murine macrophage-like cell line RAW 264.7. Systematic bioassay-guided fractionation of this extract gave an active saponin-containing fraction from which four saponins were isolated. Use of 1D (¹H, ¹³C, DEPT135) and 2D (COSY, TOCSY, HSQC, and HMBC) NMR, mass spectrometry and sugar analysis gave their structures as 3-O-(β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl)-28-O-(α-l-rhamnopyranosyl-(1 → 3)[β-d-xylopyranosyl-(1 → 4)]-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-16α-hydroxyprotobassic acid, 3-O-β-d-glucopyranosyl-28-O-(α-l-rhamnopyranosyl-(1 → 3)[β-d-xylopyranosyl-(1 → 4)]-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-16α-hydroxyprotobassic acid, 3-O-(β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl)-28-O-(α-l-rhamnopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)[β-d-apiofuranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-16α-hydroxyprotobassic acid, and the known compound, 3-O-β-d-glucopyranosyl-28-O-(α-l-rhamnopyranosyl-(1 → 3)[β-d-xylopyranosyl-(1 → 4)]-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-protobassic acid. Two further saponins were obtained from the same fraction, but as a 5:4 mixture comprising 3-O-(β-d-glucopyranosyl)-28-O-(α-l-rhamnopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)[β-d-apiofuranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-16α-hydroxyprotobassic acid and 3-O-(β-d-apiofuranosyl-(1 → 3)-β-d-glucopyranosyl)-28-O-(α-l-rhamnopyranosyl-(1 → 3)[β-d-xylopyranosyl-(1 → 4)]-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl)-16α-hydroxyprotobassic acid, respectively. This showed greater cytotoxicity (IC₅₀ = 11.9 ± 1.5 μg/ml) towards RAW 264.7 cells than the original extract (IC₅₀ = 39.5 ± 4.1 μg/ml), and the saponin-containing fraction derived from it (IC₅₀ = 33.7 ± 6.2 μg/ml).     

Stereospecific ligands and their complexes. V. Synthesis, characterization and antimicrobial activity of palladium(II) complexes with some alkyl esters of (S,S)-ethylenediamine-N,N′-di-2-propanoic acid

Three new ligands and their palladium(II) complexes of general formula [PdCl₂(R₂-S,S-eddp)] (R = n-propyl, n-butyl and n-pentyl) have been synthesized and characterized by microanalysis, infrared and ¹H and ¹³C NMR spectroscopy. Antimicrobial activity of these ligands and complexes was tested by microdilution method and both minimal inhibitory and microbicidal concentration were determined. These tested complexes demonstrated the significant antifungal activity against pathogenic fungi Aspergillus flavus and Aspergillus fumigatus. On the other hand, these complexes demonstrated moderate antibacterial activity.     

Influence of viscous Rhodella grisea (Rhodophyceae) proteoglycan on chemically induced cough reflex

An algal extracellular biopolymer (over 8.5 × 10⁵ Da) composed of carbohydrates (52%) and protein (∼13%) has been isolated from a red alga Rhodella grisea growing in natural conditions by concentration of water medium, alcohol precipitation, dialysis and freeze-drying. This mucilagineous biopolymer contained xylose and its 3-O- and 4-O-methyl derivatives (∼63%), galactose (∼12%), glucuronic acid (11-12%), glucose (∼5%), rhamnose (∼4%), fucose (∼3-4%) and low content of others accompaning sugars. When tested on the citric acid-induced cough and reactivity of airways smooth muscle in vivo in the test system guinea pigs, this biopolymer assigned a significant cough suppressing effect. The reactivity of airways smooth muscle was not affected indicating that expectoration effect was not suppressed by biopolymer application, which is important from the pharmacological point of view.     

Mononuclear iron(III) complexes supported by tripodal N3O ligands: Synthesis, structure and reactivity towards DNA cleavage

A new synthetic route to the known tripodal tetradentate N₃O ligand L¹ (HL¹ = [N-(3,5-di-tert-butyl-2-hydroxybenzyl)-N,N-di-(2-pyridylmethyl)]amine) is reported. The related compounds HLⁿ (n = 2, 3) were prepared by a similar procedure. Treatment of HLⁿ (n = 1-3) with FeCl₃·6H₂O in hot methanol led to the mononuclear iron(III) complexes [Fe(Lⁿ)Cl₂] (1: n = 1, 2: n = 2, 3: n = 3). The solid-state structures of complexes 1 and 2 were determined by X-ray crystallography. [Fe(L¹)Cl₂] (1) showed effective nuclease activity in the presence of hydrogen peroxide, converting supercoiled plasmid DNA to its linear form.     

First report of an anti-tumor, anti-fungal, anti-yeast and anti-bacterial hemolysin from Albizia lebbeck seeds

A monomeric 5.5-kDa protein with hemolytic activity toward rabbit erythrocytes was isolated from seeds of Albizia lebbeck by using a protocol that involved ion-exchange chromatography on Q-Sepharose and SP-Sepharose, hydrophobic interaction chromatography on Phenyl-Sepharose, and gel filtration on Superdex 75. It was unadsorbed on both Q-Sepharose and SP-Sepharose, but adsorbed on Phenyl-Sepharose. Its hemolytic activity was fully preserved in the pH range 0-14 and in the temperature range 0-100 °C, and unaffected in the presence of a variety of metal ions and carbohydrates. The hemolysin reduced viability of murine splenocytes and inhibited proliferation of MCF-7 breast cancer cells and HepG2 hepatoma cells with an IC₅₀ of 0.21, 0.97, and 1.37 μM, respectively. It impeded mycelial growth in the fungi Rhizoctonia solani with an IC₅₀ of 39 μM but there was no effect on a variety of other filamentous fungi, including Fusarium oxysporum, Helminthosporium maydis, Valsa mali and Mycosphaerella arachidicola. Lebbeckalysin inhibited growth of Escherichia coli with an IC₅₀ of 0.52 μM.     

Flavonol tetraglycosides from fruits of Styphnolobium japonicum (Leguminosae) and the authentication of Fructus Sophorae and Flos Sophorae

The dried fruits and seeds of Styphnolobium japonicum (L.) Schott (syn. Sophora japonica L.) are used in traditional Chinese medicine and known as Fructus Sophorae or Huai Jiao. The major flavonoids in these fruits and seeds were studied by LC-MS and other spectroscopic techniques to aid the chemical authentication of Fructus Sophorae. Among the flavonoids were two previously unreported kaempferol glycosides: kaempferol 3-O-β-glucopyranosyl(1 → 2)-β-galactopyranoside-7-O-α-rhamnopyranoside and kaempferol 3-O-β-xylopyranosyl(1 → 3)-α-rhamnopyranosyl(1 → 6)[β-glucopyranosyl(1 → 2)]-β-glucopyranoside, the structures of which were determined by NMR. Two further tetraglycosides were identified for the first time in S. japonicum as kaempferol 3-O-β-glucopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-glucopyranoside-7-O-α-rhamnopyranoside and kaempferol 3-O-β-glucopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-galactopyranoside-7-O-α-rhamnopyranoside; the latter was the main flavonoid in mature seeds. The chromatographic profiles of 27 recorded flavonoids were relatively consistent among fruits of similar ages collected from five trees of S. japonicum, and those of maturing unripe and ripe fruits were similar to a market sample of Fructus Sophorae, and thus provide useful markers for authentication of this herbal ingredient. The flower buds (Huai Mi) and flowers (Huai Hua) of S. japonicum (collectively Flos Sophorae) contained rutin as the main flavonoid and lacked the flavone glycosides that were present in flower buds and flowers of Sophora flavescens Ait., reported to be occasional substitutes for Flos Sophorae. The single major flavonoid in fruits of S. flavescens was determined as 3′-hydroxydaidzein.     

Glucosylation of the flavonoid, astragalin by Leuconostoc mesenteroides B-512FMCM dextransucrase acceptor reactions and characterization of the products

Astragalin (kaempferol-3-O-β-d-glucopyranoside, Ast) glucosides were synthesized by the acceptor reaction of a dextransucrase produced by Leuconostoc mesenteroides B-512FMCM with astragalin and sucrose. Each glucoside was purified and their structures were assigned as kaempferol-3-O-β-d-glucopyranosyl-(1 → 3)-O-α-d-glucopyranoside (or kaempferol-3-O-β-d-nigeroside, Ast-G1′) and kaempferol-3-O-β-d-glucopyranosyl-(1 → 6)-O-α-d-glucopyranoside (or kaempferol-3-O-β-d-isomaltoside, Ast-G1) for one glucose transferred, and kaempferol-3-O-β-d-isomaltooligosacharide (Ast-IMO or Ast-Gn; n = 2-8). The astragalin glucosides exhibited 8.3-60.6% higher inhibitory effects on matrix metalloproteinase-1 expression, 18.8-20.3% increased antioxidant effects, and 3.8-18.8% increased inhibition activity of melanin synthesis compared to control (without the addition of compound), depending on the number of glucosyl residues linked to astragalin. These novel compounds could be used to further expand the industrial applications of astragalin glucosides, in particular in the cosmetics industry.     

X-ray structure of a sodium salt of digeneaside isolated from red alga Ceramium botryocarpum

X-ray diffraction analysis has been recently used to determine the crystal structure of the floridoside (2-O-α-d-galactopyranosylglycerol) isolated from red alga Palmaria palmata and Dilsea carnosa, respectively [Simon-Colin, C.; Michaud, F.; Léger, J.-M.; Deslandes, E. Carbohydr. Res.2003, 338, 2413-2416; Vonthron-Senechau, C.; Sopkova-de Oliveira Santos. J.; Mussio, I.; Rusig, A. M. Carbohydr. Res. 2008, 343, 2697-2698]. In this present study, a similar analysis was performed on another compound belonging to the glycopyranosyl-glycerols family present in red algae, digeneaside. The crystal structure of a hydrated sodium salt of digeneaside (sodium 2-O-α-d-mannopyranosyl-d-glycerate monohydrate) was determined by single-crystal X-ray diffraction analysis at 110 ± 3 K. The space group is C2 with Z = 4, a = 17.9315(12), b = 6.2693(4), c = 10.7805(7) Å, beta = 90.746(7)°.     

Effects of two acanthocephalan species on the reproduction of Hyalella patagonica (Amphipoda, Hyalellidae) in an Andean Patagonian Lake (Argentina)

The aim of the present study was to evaluate alterations in the reproduction induced by acanthellae and cystacanths of the acanthocephalans Acanthocephalus tumescens and Corynosoma sp. in the amphipod Hyalella patagonica from Lake Mascardi. Specimens of H. patagonica were separated in two categories: paired amphipods (joined specimens during precopulatory mate guarding period until fertilization) and unpaired amphipods (alone specimens). Different analyses were performed: first with paired (n = 406) and unpaired (n = 375) amphipods, and second only with female amphipods (n = 1949), that were classified into three categories (without internal oocytes and eggs, only with internal oocytes, and with eggs). Also, carotenoid extraction was performed of amphipods uninfected (n = 75) and infected (n = 105) by cystacanths of Corynosoma sp. Unpaired amphipods had significantly higher prevalence of cystacanths of both acanthocephalan species than paired ones; but such differences were not found in prevalence of acanthellae. Female amphipods without internal oocytes and eggs showed significantly higher prevalence of cystacanths of both acanthocephalan species than the two other female categories; while females with eggs had significantly higher prevalence of A. tumescens acanthellae. Amphipods infected by Corynosoma sp. showed lower carotenoid concentration than uninfected ones. In Lake Mascardi, there is indirect evidence of both reduced mating success and female fecundity of H. patagonica provoked by both cystacanths species (A. tumescens and Corynosoma sp.). However, infections by acanthellae seem to have no effects.     

Resistance of the Manila clam (Venerupis philippinarum) to infection with Mikrocytos mackini

Manila clams (Venerupis philippinarum) challenged in laboratory trials via bath exposure proved to be resistant to infections with Mikrocytos mackini (protistan parasite of unknown taxonomic affiliation), while Pacific oysters (Crassostrea gigas) challenged simultaneously using identical conditions developed infections. Although M. mackini was detected by a nucleic acid pathogen specific (PCR) assay in 10-30% of the challenged V. philippinarum that were sampled soon after exposure (0-48 h, n = 40), all of the subsequent V. philippinarum (n = 62) sampled 9-17 weeks post-exposure tested negative for M. mackini by PCR assay. Prevalence of infection for the exposed C. gigas (n = 100) during this same period ranged from 50% to 100% by PCR assay. Infection was confirmed in the oysters (58%, n = 60) by a digoxigenin-labelled DNA probe designed to detect M. mackini by in situ hybridization, but M. mackini was not found in any of the exposed Manila clams (n = 63) using this technique.     

In vitro and in vivo biological activity screening of Ru(III) complexes involving 6-benzylaminopurine derivatives with higher pro-apoptotic activity than NAMI-A

A series of novel octahedral ruthenium(III) complexes involving 6-benzylaminopurine (L) derivatives as N-donor ligands has been prepared by the reaction of [(DMSO)₂H][trans-RuCl₄(DMSO)₂] with the corresponding L derivative. The complexes 1-12 have the general compositions trans-[RuCl₄(DMSO)(n-Cl-LH)] ⋅ xSol (1-3), trans-[RuCl₄(DMSO)(n-Br-LH)] · xSol (4-6), trans-[RuCl₄(DMSO)(n-OMe-LH)] · xSol (7-9) and trans-[RuCl₄(DMSO)(n-OH-LH)] · xSol (10-12); n = 2, 3, and 4, x = 0-1.5; and Sol = H₂O, DMSO, EtOH and/or (Me)₂CO. The complexes have been thoroughly characterized by elemental analysis, UV-visible, FTIR, Raman, and EPR spectroscopy, ES + (positive ionization electrospray) mass spectrometry, thermal analysis, cyclic voltammetry, magnetic and conductivity measurements. The X-ray molecular structure of trans-[RuCl₄(DMSO)(3-Br-LH)] ⋅ (Me)₂CO (5) revealed the distorted octahedral coordination in the vicinity of the central atom, and also confirmed that the 3-Br-L ligand is present as the N3-protonated N7-H tautomer and is coordinated to Ru(III) through the N9 atom of the purine moiety. The tested complexes have been found to be in vitro non-cytotoxic against K562, G361, HOS and MCF7 human cancer cell lines with IC₅₀ > 100 μM in contrast to the moderate results regarding the antiradical activity with IC₅₀ ≈ 10^− 3 M. On the contrary, in vivo antitumor activity screening showed that the prepared Ru(III) complexes possess higher pro-apoptotic activity than NAMI-A. The reduction of Ru(III) to Ru(II) and Ru(II)-species formation in tumor tissues was confirmed by means of a simple method of detection and visualization of intracellular Ru(II) by fluorescence microscopy. The originality of this method is based on the preparation of a Ru(II)-bipyridine complex in situ.