Status quo of soil petroleum contamination and evolution of bioremediation

Along with the rapid development of oil industries internationally,petroleum prospecting and exploitation activities are growing intensively.Especially in China,with the fastest economic growth in the world and shortage of petroleum resources,we are leading the practices of petroleum deep exploitation.Obviously,the risk of damage to the natural environment from these activities is high.Oil contamination in soils and groundwater is becoming a big issue along with pesticide pollution,which makes organic pollution prevention and control （OPPC） much more complex.In this paper,based on recent research on oil-contaminated soil at home and abroad,we make comments on the remediation technologies for polluted soil,emphasizing bioremediation techniques and degradation mechanisms in order to push forward research into bound organic pollution prevention and control （OPPC）,especially in China.

BIOTRANSFORMATION OF 2α，5α，10β，14β－TETRA－ACETOXY－4（20），11－TAXADIENE BY THE FUNGIJS CUNNINGHAMELLA ECHINULATA

?5α,10β,14β-Tetra-acctoxy-4(20).11-taxadicne (1) could be regioselectively transfonnedinto 6α 10β-dihydroxy-2α,5α,14β-triacetoxy-4(20). 11- taxadiene (2) by Cunninghamella echinnlata infair yield. 6βM.10β-Dihydroxy-2α,5α,14β-triacet 11-taxadienc (3). 10β-hydroxy-2α,5α,14β-triacetoxy-4(20).11-taxadiene (4), 10 β-hyboxy-4β,20-epoxy -2α,5α,14β-triacetoxy- tax - 11- ene (5)asminor prpducts were also isolated

Role of baicalin as a potential therapeutic agent in hepatobiliary and gastrointestinal disorders:A review

Baicalin is a natural bioactive compound derived from Scutellaria baicalensis,which is extensively used in traditional Chinese medicine.A literature survey demonstrated the broad spectrum of health benefits of baicalin such as antioxidant,anticancer,anti-inflammatory,antimicrobial,cardio-protective,hepatoprotective,renal protective,and neuroprotective properties.Baicalin is hydrolyzed to its metabolite baicalein by the action of gut microbiota,which is further reconverted to baicalin via phase 2 metabolism in the liver.Many studies have suggested that baicalin exhibits therapeutic potential against several types of hepatic disorders including hepatic fibrosis,xenobiotic-induced liver injury,fatty liver disease,viral hepatitis,cholestasis,ulcerative colitis,hepatocellular and colorectal cancer.During in vitro and in vivo examinations,it has been observed that baicalin showed a protective role against liver and gut-associated abnormalities by modifying several signaling pathways such as nuclear factor-kappa B,transforming growth factor beta 1/SMAD3,sirtuin 1,p38/mitogen-activated protein kinase/Janus kinase,and calcium/calmodulin-dependent protein kinase kinaseβ/adenosine monophosphate-activated protein kinase/acetyl-coenzyme A carboxylase pathways.Furthermore,baicalin also regulates the expression of fibrotic genes such as smooth muscle actin,connective tissue growth factor,β-catenin,and inflammatory cytokines such as interferon gamma,interleukin-6(IL-6),tumor necrosis factor-alpha,and IL-1β,and attenuates the production of apoptotic proteins such as caspase-3,caspase-9 and B-cell lymphoma 2.However,due to its low solubility and poor bioavailability,widespread therapeutic applications of baicalin still remain a challenge.This review summarized the hepatic and gastrointestinal protective attributes of baicalin with an emphasis on the molecular mechanisms that regulate the interaction of baicalin with the gut microbiota.

One new bufadienolide biotransformed from cinobufagin by Cunninghamella elegans

Cunninghamella elegans has been employed for the biotransformation of cinobufagin （1） to afford one metabolites. The structure of the transformation product has been characterized as 7β,12β-dihydroxylcinobufagin （2）. Product 2 is a new compound. In vitro cytotoxic activities of the biotransformation product and the substrate-cinobufagin have been assayed against HeLa; they all showed cytotoxic activities.

Transformation of berberine to its demethylated metabolites by the CYP51 enzyme in the gut microbiota

Berberine(BBR)is an isoquinoline alkaloid extracted from Coptis chinensis that improves diabetes,hyperlipidemia and inflammation.Due to the low oral bioavailability of BBR,its mechanism of action is closely related to the gut microbiota.This study focused on the CYP51 enzyme of intestinal bacteria to elucidate a new mechanism of BBR transformation by demethylation in the gut microbiota through multiple analytical techniques.First,the docking of BBR and CYP51 was performed;then,the pharmacokinetics of BBR was determined in ICR mice in vivo,and the metabolism of BBR in the liver,kidney,gut microbiota and single bacterial strains was examined in vitro.Moreover,16S rRNA analysis of ICR mouse feces indicated the relationship between BBR and the gut microbiota.Finally,recombinant E.coli containing cyp51 gene was constructed and the CYP51 enzyme lysate was induced to express.The metabolic characteristics of BBR were analyzed in the CYP51 enzyme lysate system.The results showed that CYP51 in the gut microbiota could bind stably with BBR,and the addition of voriconazole(a specific inhibitor of CYP51)slowed down the metabolism of BBR,which prevented the production of the demethylated metabolites thalifendine and berberrubine.This study demonstrated that CYP51 promoted the demethylation of BBR and enhanced its intestinal absorption,providing a new method for studying the metabolic transformation mechanism of isoquinoline alkaloids in vivo.

Biotransformation of 14-Deacetoxy-13-oxo sinenxan A by Ginkgo Cell Cultures

Deacetoxy-13-oxo sinenxan A (1) was converted to 9a-hydroxy-13-oxo-2a, 5a, 10b-triacetoxy-4(20),11-taxadiene (2) and 10b-hydroxy-13-oxo-2a,5a,9a-triacetoxy- 4(20), 11- taxadiene (3) by Ginkgo cell suspension cultures in 45% and 15% yields, respectively.

Two new compounds derived from bufalin

The biotransformation of bufalin by cell suspension cultures of Platycodon grandifiorus was investigated and two new biotransformed products were obtained, which was 3-epi-telocinobufagln and 3-epi-bufalin-3-O-β-D-glucoside.

Rhamnolipids Induced by Glycerol Enhance Dibenzothiophene Biodegradation in Burkholderia sp. C3

In highly urbanized areas,pollution from anthropogenic activities has compromised the integrity of the land,decreasing soil availability for agricultural practices.Dibenzothiophene(DBT)is a heterocyclic aromatic hydrocarbon frequently found in urbanized areas,and is often used as a model chemical to study the microbial transformation of pollutants.The potential for human exposure and its health risk makes DBT a chemical of concern;thus,it needs to be environmentally managed.We utilized glycerol to stimulate Burkholderia sp.C3 in order to degrade DBT in respect to①DBT biodegradation kinetics,②bacterial growth,③rhamnolipid(RL)biosynthesis,and④RL secretion.Under an optimum glycerol-to-DBT molar ratio,the DBT biodegradation rate constants increased up to 18-fold and enhanced DBT biodegradation by 25%–30%at day 1 relative to cultivation with DBT alone.This enhancement was correlated with an increase in bacterial growth and RL biosynthesis.Proteomics studies revealed the enzymes involved in the upper and main steps of RL biosynthesis.The RL congeners Rha-C10-C10,Rha-Rha-C10-C10,Rha-Rha-C10-C12,and Rha-Rha-C12-C12 were identified in the medium supplemented with glycerol and DBT,whereas only Rha-C12-C12 was identified in cultures without glycerol or with RL inhibitors.The studies indicated that glycerol enhances DBT biodegradation via increased RL synthesis and bacterial growth.The results warrant further studies of environmental biostimulation with glycerol to advance bioremediation technologies and increase soil availability for agricultural purposes.

Optimization of Fermentation Medium for Producing α-Hydroxyphenylacetic Acid by Using Plackett-Burman Design and Response Surface Methodology

Plackett-Burman design and response surface methodology were applied in order to optimize the fermentation medium of (R)-α-hydroxyphenylacetic acid ((R)-HPA) producing Bacillus sp. HZG-19. The factors playing important roles in the production of (R)-HPA were selected based on Plackett-Burman design. The path of steepest ascent was undertaken to optimize said fermentation medium. Finally, the optimal levels of the factors with the greatest change in regard to product yield were further optimized using Box-Behnken and response surface analysis. The optimal conditions were found to be as follows: casein peptone 30.49 (g × L-1), glycerol 14.09 (g × L-1), KH2PO4 0.1345 (g × L-1), K2HPO4 0.01 (g × L-1), CaCl2 0.1 (g × L-1), MnSO4 0.01 (g × L-1). Under the optimal conditions described above, the yield of (R)-HPA reached 63.30%, which indicated an increase of 14.9%, as compared to the yield obtained before optimization.

A New Saponin Transformed from Ginsenoside Rh_1 by Bacillus subtilis

A novel saponin was isolated from the transformed products of ginsenoside Rh1 by Bacillus subtilis. It's structure was determined to be 3-O-β-D-glucopyranosyl-6-O-β-D-gluco- pyranosyl-20 (S)-protopanaxatriol on the basis of the spectral data.

Preparation and Crystal Structure of 15α-Hydroxyl-oleanolic Acid

The compound 15α-hydroxyl-oleanolic acid was biotransformed from oleanolic acid with Colletotrichum lini AS3.4486,and its structure was characterized by 1H NMR,13C NMR,HR-ESI-MS and single-crystal X-ray diffraction.The crystal of the title compound belongs to monoclinic,space group R3 with a=34.255（5）,b=34.255（5）,c=6.8671（14）,β=90°,Z=9,V=6978（2）3,Mr=490.70,Dc=1.051 mg/m3,μ=0.069 mm-1,F（000）=2430,R=0.0375 and wR=0.0808.The title compound is stacked into a three-dimensional network through hydrogen bonds.

Biological transformation,kinetics and dose-response assessments of bound musk ketone hemoglobin adducts in rainbow trout as biomarkers of environmental exposure

Low levels (ng/g) of musk ketone (MK),used as a fragrance additive in the formulation of personal care products,are frequently detected in the water and other environment.Thus,aquatic organisms can be continuously exposed to MK.In this study,kinetics and dose-response assessments of 2-amino-MK (AMK) metabolite,bound to cysteine-hemoglobin (Hb) in rainbow trout,formed by enzymatic nitro-reduction of MK have been demonstrated.Trout were exposed to a single exposure of 0.010,0.030,0.10,and 0.30 mg MK/g fish.Tw...

Glucuronidation is the dominating in-vivo metabolism pathway of herbacetin:elucidation of herbacetin pharmacokinetics after intravenous and oral administration in rats

OBJECTIVE To map a comprehensive metabolic pathway of herbacetin in rats,specifically,to elucidate the biotransformation of herbacetin in vivo and to simultaneously monitor the pharmacokinetic process of both parent drug and its major metabolites.METHODS liquid chromatography/ion trap mass spectrometry(LC/MS n) and ultra-liquid chromatography coupled with mass spectrometry(UPLC/MS) were combined in the current study for qualitative and quantitative determinations of herbacetin and its metabolites in bile,urine and feces after both oral and intravenous administration of herbacetin to rats.Enzyme kinetic studies on the intestinal and hepatic metabolism of herbacetin were further conducted to elucidate metabolic profiles of herbacetin in rat tissues and organs.Additionally,plasma concentration profiles of herbacetin and its metabolites in rats were obtained to characterize the overall pharmacokinetic behavior of herbacetin.RESULTS It was found that herbacetin was excreted primarily from rat urine in the form of glucuronide-conjugations.Subsequent in vitro enzyme kinetic studies and in vivo pharmacokinetic investigations suggested an extensive hepatic metabolism of herbacetin and the high exposure of herbacetin-glucuronides in systemic circulation.The clearance,half-life and bioavailability of herbacetin in rats were determined as(16.4±1.92)mL·kg^(-1)·min^(-1),(11.9±2.7)min,and 1.32%,respectively.On basis of these findings,a comprehensive metabolic pathway of herbacetin in rats was composed.In addition,a physiology based pharmacokinetic(PBPK) model was successfully developed with the aid of the Gastro Plus to simulate the pharmacokinetic process of herbacetin in rats.Application of the PBPK modeling can provide a useful starting point to understand and extrapolate pharmacokinetic parameters among different species,populations,and disease states.CONCLUSION After oral administration,herbacetin was subjected to colonic degradation and extensive first pass metabolism,with glucuronidation as its dominating in vivo metabolic pathway.

Reduction of 4-nitrophenol catalyzed by nitroreductase

The reduction of 4-nitrophenol catalyzed by nitroreductase in the presence of NADH was investigated in this paper. 4-Amino- phenol and 4-hydroxylamino-phenol were found in the reductive products. The relationship between reaction time and the reductive ratio were studied. The similar reducing ratios of 4-nitrophenol were obtained under aerobic and anaerobic conditions. The results indicated that an oxygen-insensitive reaction was proceeded in the reduction of 4-nitrophenol and nitroreductase was an oxygeninsensitive enzyme. The reductive products of 4-nitrophenol were determined by HPLC and MS.

Time-course monitoring of in vitro biotransformation reaction via solid-phase microextraction-ambient mass spectrometry approaches

The solid-phase microextraction technique quantifies analytes without considerably affecting the sample composition.Herein,a proof-of-concept study was conducted to demonstrate the use of coated probe electrospray ionization(coated-PESI)and coated blade spray(CBS)as ambient mass spectrometry approaches for monitoring drug biotransformation.The ability of these methods was investigated for monitoring the dephosphorylation of a prodrug,combretastatin A4 phosphate(CA4P),into its active form,combretastatin A4(CA4),in a cell culture medium supplemented with fetal bovine serum.The CBS spot analysis was modified to achieve the same extraction efficiency as protein precipitation and obtained results in 7 min.Because coated-PESI performs extraction without consuming any samples,it is the preferred technique in the case of a limited sample volume.Although coated-PESI only extracts small quantities of analytes,it uses the desorption solvent volume of 5-10 pL,resulting in high sensitivity,thus allowing the detection of compounds after only 1 min of extraction.The biotransformation of CA4P into CA4 via phosphatases occurs within the simple matrix,and the proposed sample preparation techniques are suitable for monitoring the biotransformation.

Synthesis of 17-OH-Isosteviol

Stevioside（1）, an ent-kaurene glycoside commercially extracted from Stevia rebaudiana Bertoni is used as a non-caloric sweetener for food in many countries. The increasing demand for low calory and natural food contributes to the increasing popularity of that glycoside. It has recently been demonstrated that stevioside and its derivatives have inhibitory effects on the inflammatory ear edema of mice and suppress the tumor-promoting effect in mouse skin.