Gene cloning and characterization of a novel esterase from activated sludge metagenome

A metagenomic library was prepared using pCC2FOS vector containing about 3.0 Gbp of community DNA from the microbial assemblage of activated sludge. Screening of a part of the un-amplified library resulted in the finding of 1 unique lipolytic clone capable of hydrolyzing tributyrin, in which an esterase gene was identified. This esterase/lipase gene consists of 834 bp and encodes a polypeptide (designated EstAS) of 277 amino acid residuals with a molecular mass of 31 kDa. Sequence analysis indicated that it showed 33% and 31% amino acid identity to esterase/lipase from Gemmata obscuriglobus UQM 2246 (ZP_02733109) and Yarrowia lipolytica CLIB122 (XP_504639), respectively; and several conserved regions were identified, including the putative active site, HSMGG, a catalytic triad (Ser92, His125 and Asp216) and a LHYFRG conserved motif. The EstAS was overexpressed, purified and shown to hydrolyse p-nitrophenyl (NP) esters of fatty acids with short chain lengths (≤ C8). This EstAS had optimal temperature and pH at 35°C and 9.0, respectively, by hydrolysis of p-NP hexanoate. It also exhibited the same level of stability over wide temperature and pH ranges and in the presence of metal ions or detergents. The high level of stability of esterase EstAS with its unique substrate specificities make itself highly useful for biotechnological applications

Separation and Purification of Two Flavone Glucuronides from Erigeron multiradiatus (Lindl.) Benth with Macroporous Resins

Scutellarein-7-O-β-D-glucuronide (SG) and apigenin-7-O-β-D-glucuronide (AG) are two major bioactive constituents with known pharmacological effects in Erigeron multiradiatus. In this study, a simple method for preparative separation of the two flavone glucuronides was established with macroporous resins. The performance and adsorption characteristics of eight macroporous resins including AB-8, HPD100, HPD450, HPD600, D100, D101, D141, and D160 have been evaluated. The results confirmed that D141 resin offered the best adsorption and desorption capacities and the highest desorption ratio for the two glucuronides among the tested resins. Sorption isotherms were constructed for D141 resin under optimal ethanol conditions and fitted well to the Freundlich and Langmuir models (R2 > 0.95). Dynamic adsorption and desorption tests was performed on column packed with D141 resin. After one-run treatment with D141 resin, the two-constituent content in the final product was increased from 2.14% and 1.34% in the crude extract of Erigeron multiradiatus to 24.63% and 18.42% in the final products with the recoveries of 82.5% and 85.4%, respectively. The preparative separation of SG and AG can be easily and effectively achieved via adsorption and desorption on D141 resin, and the method developed can be referenced for large-scale separation and purification of flavone glucuronides from herbal raw materials

Separation and purification of two flavone glucuronides from Erigeron multiradiatus (Lindl.) Benth with macroporous resins

Scutellarein-7-O-β-D-glucuronide (SG) and apigenin-7-O-β-D-glucuronide (AG) are two major bioactive constituents in Erigeron multiradiatus. In this study, a simple method for preparative separation of the two flavone glucuronides was established with macroporous resins. The performance and adsorption characteristics of eight macroporous resins including AB-8, HPD100, HPD450, HPD600, D100, D101, D141 and D160 had been evaluated. The results confirmed that D141 resin was preferred choice, which offered the best adsorption and desorption capacities for the two glucuronides among the tested resins. Sorption isotherms were constructed for D141 resin and fitted well to the Freundlich and Langmuir models (R 2 > 0.95). After one run treatment with D141 resin, the two constituents' content was increased from 2.14% and 1.34% in the crude extract of E. multiradiatus to 24.63% and 18.42% in the final products with the recoveries of 82.5% and 85.4%, respectively. The enrichment of SG and AG can be easily and effectively achieved via adsorption and desorption on D141 resin, and the method can be referenced for large-scale separation and purification of flavone glucuronides from herbal raw materials

catena-Poly[[aqua­[3-(3-pyrid­yl)acrylato]gadolinium(III)]-bis­[μ-3-(3-pyrid­yl)acrylato]]

In the title compound, [Gd(C8H6NO2)3(H2O)]n, the gadolinium(III) ion is coordinated by eight carboxyl­ate O atoms and one water mol­ecule. The carboxyl­ate ligands bridge pairs of gadolinium(III) ions, forming a zigzag chain along [100]. Hydrogen bonds link the chains into sheets parallel to (001)

2-Methyl-1-phenyl-1H-indole-3-carbo­nitrile

In the title compound, C16H12N2, the dihedral angle between the indole ring system and the pendant phenyl ring is 64.92 (5)°. The crystal packing features aromatic π–π stacking [centroid–centroid separation = 3.9504 (9) Å] and C—H⋯π inter­actions