Double Bond-Transferring Novel Hydroxylation Reaction Involved in Microbial Metabolism of Plant Essential Oil Eugenol

We isolated a eugenol-degrading bacterium Pseudomonas fluorescens E 118.This strain produced a novel enzyme,eugenol dehydrogenase which catalyzes the formation of coniferyl alcohol from eugenol.The enzyme required an electron acceptor such as phenazione methosulface(PMS).The enzyme was purified 242-fold with a 22.4% overall recovery from the eugenol-induced cells of P.fluorescens E118.The purified enzyme appeared to be homogeneous,judging from the analysis of polyacrylamide gel electrophoresis.The enzyme was a 68.6 kDa protein composed of two different subunits (α　subunit 10.4kDa and βsubunit 58.2kda).The enzyme exhibited a cytochrome c-like absorption.The α subunit containing heme c seemed to play an important role for the dehydrogenation reaction.The enzyme also catalyzes the dehydrogenation of 4-alkylphenol into the corresponding alkyl 1-(4-hydroxyphenyl)-alcohol,and vanillyl alchol into vanillin,respectively.The reaction products were isolated and identified.These reaction seemed to proceed through the same mechanisms.植物精油eugenolは自然界に広く存在し、安価な農業余剰産物である。オイゲノールはPseudomonas属やCorynebacterium属細菌によってFig.1に示したように代謝されることが知られている。この中でオイゲノールからコニフェルアルコールへの変換は二重結合が移動すると同時に酸化されるユニークな反応が予想されるが、この変換に関する酵素化学的知見は全く得られていない。オイゲノール代謝における中間体フェルラ酸は抗酸化剤、医薬品出発原料となり、また、コニフェリルアルコールは高価な香料として知られている。本報ではP.fluorescensE118のオイゲノール代謝について、酵素レベルでの検討を試みた

13C-NMR Spectroscopic Study on Chemical Species in Piperazine−Amine−CO2−H2O System before and after Heating

AbstractChemical reactions associated with the absorption of CO2 into aqueous solutions of blends of piperazine (PZ) with N- methyldiethanolamine (MDEA), etc. were studied by 13C-NMR spectroscopy. The coexistence of PZ and MDEA enhanced the initial apparent rate of HCO3−/CO2−3 formation. This result can be explained by considering that PZ−monocarbamate rapidly formed works as an organocatalyst in the formation reaction of HCO−3. Concentration changes of chemical species in CO2-absorbed aqueous amine solutions upon heating (80°C, 30min) were studied by 13C-NMR spectroscopy. Carbon dioxide regeneration originates mainly from HCO3−/CO3, and not form carbamate and carbonate

Targeting of MAPK-associated molecules identifies SON as a prime target to attenuate the proliferation and tumorigenicity of pancreatic cancer cells

Abstract Background Pancreatic cancer is characterized by constitutive activation of mitogen-activated protein kinase (MAPK). Activation of MAPK is associated with the upregulation of genes implicated in the proliferation and survival of pancreatic cancer cells. We hypothesized that knockdown of these MAPK-associated molecules could produce notable anticancer phenotypes. Methods A RNA interference-mediated knockdown screening of 78 MAPK-associated molecules previously identified was performed to find molecules specifically associated with proliferation of pancreatic cancer cells in vitro. Expression of an identified molecule in pancreatic cancer tissues was examined by immunohistochemistry. In vivo tumorigenicity of cancer cells with stable knockdown of the molecule was assayed by using xenograft models. Flow cytometry and live cell imaging were employed to assess an association of the molecule with cell cycle. Results The knockdown screening revealed that knockdown of SON, the gene encoding SON, which is a large serine/arginine-rich protein involved in RNA processing, substantially suppressed pancreatic cancer cell proliferation and survival in vitro and tumorigenicity in vivo. SON expression was higher in ductal adenocarcinomas than in cells of normal ducts and precursor lesions in pancreatic cancer tissues. Knockdown of SON induced G2/M arrest and apoptosis in cultured cancer cells. The suppressive effect of SON knockdown on proliferation was less pronounced in cultured normal duct epithelial cells. SON formed nuclear speckles in the interphase of the cell cycle and dispersed in the cytoplasm during mitosis. Live cell imaging showed that SON diffusely dispersed in the early mitotic phase, accumulated in some foci in the cytoplasm in the late mitotic phase, and gradually reassembled into speckles after mitosis. Conclusion These results indicate that SON plays a critical role in the proliferation, survival, and tumorigenicity of pancreatic cancer cells, suggesting that SON is a novel therapeutic molecular target for pancreatic cancer.</p

Expression of a fungal laccase fused with a bacterial cellulose-binding module improves the enzymatic saccharification efficiency of lignocellulose biomass in transgenic Arabidopsis thaliana

Delignification is effective for improving the saccharification efficiency of lignocellulosic biomass materials. We previously identified that the expression of a fungal laccase (Lac) fused with a bacterial cellulose-binding module domain (CBD) improved the enzymatic saccharification efficiency of rice plants. In this work, to evaluate the ability of the Lac-CBD fused chimeric enzyme to improve saccharification efficiency in a dicot plant, we introduced the chimeric gene into a dicot model plant, Arabidopsis thaliana. Transgenic plants expressing the Lac-CBD chimeric gene showed normal morphology and growth, and showed a significant increase of enzymatic saccharification efficiency compared to control plants. The transgenic plants with the largest improvement of enzymatic saccharification efficiency also showed an increase of crystalline cellulose in their cell wall fractions. These results indicated that expression of the Lac-CBD chimeric protein in dicotyledonous plants improved the enzymatic saccharification of plant biomass by increasing the crystallinity of cellulose in the cell wall