Two-Fermi-surface superconducting state and a nodal d-wave energy gap of the electron-doped Sm1.85Ce0.15CuO(4-δ) cuprate superconductor.

We report on laser-excited angle-resolved photoemission spectroscopy in the electron-doped cuprate Sm1.85Ce0.15CuO(4-δ). The data show the existence of a nodal hole-pocket Fermi surface both in the normal and superconducting states. We prove that its origin is long-range antiferromagnetism by an analysis of the coherence factors in the main and folded bands. This coexistence of long-range antiferrmagnetism and superconductivity implies that electron-doped cuprates are two-Fermi-surface superconductors. The measured superconducting gap in the nodal hole pocket is compatible with a d-wave symmetry.

Structures and antimicrobial activities of pyridoacridine alkaloids isolated from different chromotypes of the ascidian Cystodytes dellechiajei.

Three new pentacyclic alkaloids were isolated from different chromotypes of the western Mediterranean ascidian Cystodytes dellechiajei. The purple color morph collected in Catalonia contained the known compounds kuanoniamine D (1), shermilamine B (2), N-deacetylkuanoniamine D (3), and styelsamine C (4) and a new alkaloid named N-deacetylshermilamine B (5). The green color morph collected in the Balearic Islands contained the known compounds 11-hydroxyascididemin (6) and 8,9-dihydro-11-hydroxyascididemin (7) and two new alkaloids named cystodimine A (8) and cystodimine B (9). The blue color morph collected in Catalonia yielded the known compound ascididemin (10). The structures of all compounds were elucidated on the basis of spectroscopic data, mainly 1D and 2D NMR data. The antimicrobial potential of the pyridoacridine alkaloids isolated from each color morph was evaluated and compared.

Characterisation of the gill mucosal bacterial communities of four butterflyfish species: a reservoir of bacterial diversity in coral reef ecosystems.

While recent studies have suggested that fish mucus microbiota play an important role in homeostasis and prevention of infections, very few studies have investigated the bacterial communities of gill mucus. We characterised the gill mucus bacterial communities of four butterflyfish species and although the bacterial diversity of gill mucus varied significantly between species, Shannon diversities were high (H = 3.7-5.7) in all species. Microbiota composition differed between butterflyfishes, with Chaetodon lunulatus and C. ornatissimus having the most similar bacterial communities, which differed significantly from C. vagabundus and C. reticulatus. The core bacterial community of all species consisted of mainly Proteobacteria followed by Actinobacteria and Firmicutes. Chaetodonlunulatus and C. ornatissimus bacterial communities were mostly dominated by Gammaproteobacteria with Vibrio as the most abundant genus. Chaetodonvagabundus and C. reticulatus presented similar abundances of Gammaproteobacteria and Alphaproteobacteria, which were well represented by Acinetobacter and Paracoccus, respectively. In conclusion, our results indicate that different fish species present specific bacterial assemblages. Finally, as mucus layers are nutrient hotspots for heterotrophic bacteria living in oligotrophic environments, such as coral reef waters, the high bacterial diversity found in butterflyfish gill mucus might indicate external fish mucus surfaces act as a reservoir of coral reef bacterial diversity.

Isolation and bioactivities of epidioxysterol from the tunicate Cynthia savignyi.

From a hexane extract of the tunicate Cynthia savignyi, collected in Morocco, epidioxysterol or 5,8-alpha-epidioxy-5alpha-cholest-6-en-3beta-ol has been isolated. This is the first example of epidioxysterol found in the tunicate C. savignyi. The structure of epidioxysterol has been characterised by NMR data (1H, 13C and 2D). Epidioxysterol possesses antifungal activity against three tomato pathogenic fungi: Botrytis cinerea, Fusarium oxysporum and Verticillium albo atrum and antibacterial activity against Agrobacterium tumefaciens, Escherichia coli, Staphylococcusfaecalis, Staphylococcus aureus and Pseudomonas aeruginosa and cytotoxicity against Artemia salina larvae.

Cynthichlorine: a bioactive alkaloid from the tunicate Cynthia savignyi.

From ether extracts of the tunicate Cynthia savignyi, collected in Morocco, a new alkaloid-cynthichlorine-has been isolated. The structure of cynthichlorine has been characterized by extensive 2D-NMR data. Cynthichlorine possesses antifungal activity against two tomato pathogenic fungi: Botrytis cinerea and Verticillium albo atrum and antibacterial activity against Agrobacterium radiobacter, Escherichia coli and Pseudomonas aeruginosa and cytotoxicity against Artemia salina larvae.

Rapid resolution liquid chromatography-mass spectrometry determination of SAR97276 in monkey matrices. Pharmacokinetics in rhesus monkey infected by Plasmodium cynomolgi.

Since several years, we developed a new class of antimalarial drugs targeting the phospholipid metabolism of the Plasmodium falciparum malaria parasite. The bis-thiazolium compound, SAR97276, is the lead compound and is now in clinical development. In this paper, we applied the fast rapid resolution liquid chromatography-mass spectrometry technique to the analysis of SAR97276 in monkey matrices. The sample pre-treatment procedure involved an acidic precipitation of proteins followed by solid-phase extraction. The monocationic compound, T2, was used as internal standard. A good separation was achieved on a Zorbax eclipse XDB C8 column (1.8 microm, 50 mm x 4.6mm) with a mobile phase consisting of acetonitrile-trimethylamine-formate buffer (pH 3) gradient elution. The total run time was 8 min. Inter-assay precisions were <10% in plasma, and 85% in plasma, and >75% in blood. The lower limits of quantitation were 3.3 microg/l in plasma and 3.3 microg/kg in blood. No matrix effect was observed. This newly developed method is sensitive, selective, reproducible, and stability indicating. It was used to analyse samples taken during a pharmacokinetic/pharmacodynamic study carried out in infected Rhesus monkey by Plasmodium cynomolgi as part of the ongoing development of SAR97276.

Absence of a loss of in-plane infrared spectral weight in the pseudogap regime of Bi(2)Sr(2)CaCu(2)O(8+delta).

The ab-plane reflectance of Bi(2)Sr(2)CaCu(2)O(8+delta) (Bi-2212) thin films was measured in the 30-25 000 cm(-1) range for one underdoped ( T(c) = 70 K), and one overdoped sample ( T(c) = 63 K) down to 10 K. We find similar behaviors in the temperature dependence of the normal-state infrared response of both samples. Above T(c), the effective spectral weight, obtained from the integrated conductivity, does not decrease when T decreases, so that no opening of an optical pseudogap is seen. We suggest that these are consequences of the pseudogap opening in the k = (0,pi) direction and of the in-plane infrared conductivity being mostly sensitive to the k = (pi,pi) direction.

Binding to DNA and cytotoxic evaluation of ascididemin, the major alkaloid from the Mediterranean ascidian Cystodytes dellechiajei.

The isolation of ascididemin from the Mediterranean ascidian Cystodytes dellechiajei is described. This alkaloid consists of a planar pentacyclic chromophore which was investigated for its DNA-binding and cytotoxic properties. Spectroscopic measurements provided evidence that the drug intercalates into DNA. DNase I footprinting assays indicated that the binding of ascididemin to GC-rich sequences is favoured over binding to AT-rich and mixed sequences. Chemical probes were used to detect ligand-induced structural changes in DNA. The alkaloid induces a hyper-reactivity of the DNA towards potassium permanganate, but not towards diethylpyrocarbonate, just as is the case with ethidium bromide; it has little effect on the catalytic activities of topoisomerases I and II. Ascididemin exhibits marked cytotoxicity towards human leukaemic cells in vitro and appears to be practically equally toxic for drug-sensitive and multidrug-resistant cell lines. The results suggest that DNA, but not topoisomerases, may represent the critical cellular target at which this marine alkaloid exhibits its potent cytotoxic properties in vitro.