Altererythrobacter dongtanensis sp. nov., isolated from a tidal flat.

A Gram-negative, rod-shaped and non-spore-forming bacterial strain, JM27(T), was isolated from a tidal flat of Dongtan Wetland, Chongming Island, China. The strain formed smooth yellow colonies on R2A plates. Growth occurred at 10-37 °C (optimum, 30-37 °C), at pH 6.0-10.0 (optimum, pH 7.0-9.0) and in the presence of 0-1 % NaCl (optimum, 0 %). Catalase test was positive and oxidase test was negative. Ubiquinone 10 (Q10) was the major respiratory quinone. C18:0ω7c and C17:1ω6c were the most abundant fatty acids. Diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol were the major polar lipids. The DNA G+C content of strain JM27(T) was 66.4 mol%. The 16S rRNA gene sequence of the isolate showed highest similarity to that of Altererythrobacter marinus H32(T) (96.4 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain belonged to the genus Altererythrobacter of the family Erythrobacteraceae of the class Alphaproteobacteria. On the basis of phylogenetic analysis, whole-cell fatty acids, polar lipid compositions, and biochemical and physiological characteristics, strain JM27(T) is proposed to represent a novel species of the genus Altererythrobacter for which the name Altererythrobacter dongtanensis sp. nov. is proposed. The type strain is JM27(T) ( = KCTC 22672(T)  = CCTCC AB 209199(T)).

Characterization of alpha-nitromethyl ketone as a new zinc-binding group based on structural analysis of its complex with carboxypeptidase A.

Zinc-binding groups (ZBGs) are exhaustively applied in the development of the new inhibitors against a wide variety of physiologically and pathologically important zinc proteases. Here the alpha-nitro ketone was presented as a new ZBG, which is a transition-state analog featured by the unique bifurcated hydrogen bonds at the active site of carboxypeptidase A based on the structural analysis. Introduction of a nitro group at the alpha-position of the ketone could provide more non-covalent interactions without loss of the abilities to form a tetrahedral transition-state analog.

Nitro as a novel zinc-binding group in the inhibition of carboxypeptidase A.

2-Substituted 3-nitropropanoic acids were designed and synthesized as inhibitors against carboxypeptidase A (CPA). (R)-2-Benzyl- 3-nitropropanoic acid showed a potent inhibition against CPA (K(i)=0.15 microM). X-ray crystallography discloses that the nitro group well mimics the transition state occurred in the hydrolysis catalyzed by CPA, that is, an O,O'-bidentate coordination to the zinc ion and the two respective hydrogen bonds with Glu-270 and Arg-127. Because the nitro group is a planar species, we proposed (R)-2-benzyl-3-nitropropanoic acid as a pseudo-transition-state analog inhibitor against CPA.

Synthesis of some quinoline-2(1H)-one and 1, 2, 4 - triazolo [ 4 , 3 -a ] quinoline derivatives as potent anticonvulsants.

PURPOSE: A new series of substituted quinoline-2(1H)-one and 1,2,4-triazolo[4,3-a]-quinoline derivatives were designed and synthesized to meet the structural requirements essential for anticonvulsant properties. METHODS: 4-substituted-phenyl-3,4-dihydro-2(1H)-quinolines, 5-substituted-phenyl-4,5-dihydro-1,2,4-triazolo[4,3a]quinolines and 5-substituted-phenyl-4,5-dihydro-1,2,4-triazolo-[4,3-a]quinoline-1-(2H)-ones derivatives were synthesized using 3-substituted-phenyl-N-phenyl-acrylamide as a starting material. Their anticonvulsant activity were evaluated by maximal electroshock (MES) test, subcutaneous pentylenetetrazol (scPTZ) test, and their neurotoxic effects were determined by the rotarod neurotoxicity test. RESULTS: The compounds 4-substitued-phenyl-3,4-dihydro-2(1H)-quinolines (2a-f) had increased anticonvulsant effects compared to the parental compounds. The compounds 5-substituted-phenyl-4,5-dihydro-1,2,4-triazolo[4,3-a]quinolines (3a-f) had significantly increased anticonvulsant activity compared to 2a-f. However, the compounds 5-substituted-phenyl-4,5-dihydro-1,2,4-triazolo[4,3-a]quinoline-1(2H)-ones(4a-f), exhibited no anticonvulsant effects even under a high dose of 300 mg/kg. CONCLUSIONS: The triazole, but not the triazolone, modified series showed stronger anticonvulsant effects than the parent compounds. Among them, compound (3f), 5-(p-fluorophenyl)-4,5-dihydro-1,2,4-triazolo[4,3-a]quinoline, showed the strongest anticonvulsant effect with ED50 of 27.4mg/kg and 22.0mg/kg in the anti-MES and anti-PTZ test, respectively.

Antioxidant and anti-inflammatory activities of N-acetyldopamine dimers from Periostracum Cicadae.

A known N-acetyldopamine dimer, (2R,3S)-2-(3',4'-dihydroxyphenyl)-3-acetylamino-7-(N-acetyl-2''-aminoethyl)-1,4-benzodioxane (1) and a new N-acetyldopamine dimer, (2R,3S)-2-(3',4'-dihydroxyphenyl)-3-acetylamino-7-(N-acetyl-2''-aminoethylene)-1,4-benzodioxane (2) were isolated from the methanolic extracts of Periostracum Cicadae. Compounds 1 and 2 inhibited the Cu2+ -mediated, 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH)-mediated, and 3-morpholinosydnonimine (SIN)-1-mediated LDL oxidation in the thiobarbituric acid-reactive substances (TBARS) assay. The antioxidant activities of 1 and 2 were tested with respect to other parameters, such as lag time of conjugated diene formation, relative electrophoretic mobility (REM), and apoB-100 fragmentation on copper-mediated LDL-oxidation. Compounds 1 and 2 also showed 1,1-diphenyl-2-picrylhydrasyl (DPPH) radical scavenging activity. Compound 2 was more efficient than compound 1 at inhibiting the reactive oxygen species (ROS) generation, nitric oxide (NO) production, and nuclear factor-kappaB (NF-kappaB) activity as well as the expression of pro-inflammatory molecules such as inducible nitric oxide synthase (iNOS), interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and cyclooxygenase (COX)-2 in LPS-induced RAW264.7 cells.

Acyl-CoA: cholesterol acyltransferase inhibitory activities of fatty acid amides isolated from Mylabris phalerate Pallas.

Unsaturated fatty acid amides, 9(Z)-octadecenamide (2) and 9(Z),12(Z)-octadecadienamide (4) as inhibitors of acyl-CoA: cholesterol acyltransferase (ACAT) were isolated from the ethyl acetate extracts of the insect, Mylabris phalerate Pallas, and elucidated by their spectroscopic data analysis. Compounds 2 and 4 inhibited rat liver microsomal ACAT, hACAT-1, and hACAT-2 with IC(50) values of 170, 85, and 63 microM for 2 and of 151, 53, and 45 microM for 4, respectively.

Optically active 2-benzyl-3-methanesulfinylpropanoic acid: Synthesis and evaluation as inhibitors for carboxypeptidase A.

All four possible stereomers of 2-benzyl-3-methanesulfinylpropanoic acid were synthesized and evaluated as inhibitors for carboxypeptidase A to find that the isomer having the (2S,4S)-configuration is most potent followed by isomers of (2R,4S)- and (2S,4R)-configurations. The stereochemical preferences shown by the isomers of the inhibitor in binding to the enzyme suggest that the sulfoxide oxygen in the inhibitor fails to ligate the active site zinc ion but may form a hydrogen bond with the guanidinium moiety of Arg-127 like the carbonyl oxygen of scissile peptide bond of oligopeptide substrate of the enzyme does. It may thus be inferred that a sulfoxide moiety may serve as an isosterer of a carboxamide moiety.