Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants, which have received widespread attentions due to their carcinogenic and mutagenic toxicity. The microbial degradation of PAHs are usually started from the hydroxylation, followed by dehydrogenation, ring cleavage and step-by-step removal of branched chains, and finally mineralized by the tricarboxylic acid cycle. Rieske type non-heme iron aromatic ring-hydroxylating dioxygenases (RHOs) or cytochrome P450 oxidases are responsible for the conversion of hydrophobic PAHs into hydrophilic derivatives by the ring hydroxylation. The ring hydroxylation is the first step of PAHs degradation and also one of the rate-limiting steps. Here, we review the distribution, substrate specificity, and substrate recognition mechanisms of RHOs, along with some techniques and methods used for the research of RHOs and PAHs.
Bacteria/metabolism* ; Biodegradation, Environmental ; Dioxygenases/metabolism* ; Iron ; Polycyclic Aromatic Hydrocarbons ; Substrate Specificity

Indigo and indigo-like pigments are widely used in the industry of textile, food and medicine. Now people pays more and more attention to developing an alternative method of indigo production which is "environment-friendy", especially microbial biosynthesis of indigo. Many microorganisms involved in the biosynthesis of indigo have been isolated and characterized, and monooxygenase and dioxygenase have been identified to catalyze indigo biosynthesis. Some genes encoding for these enzymes have been cloned and used to construct "engineering bacteria". With this kind of bacteria, more efficient fermentation systems for indigo production have been exploited. In the meantime, biotransformation of the indigo produced by microorganisms has been under investigation. These progresses will bring us a greener method of indigo and indigo-like pigments production.
Biotechnology ; Coloring Agents ; metabolism ; Dioxygenases ; metabolism ; Fermentation ; Indigo Carmine ; Indoles ; metabolism ; Mixed Function Oxygenases ; metabolism ; Pseudomonas ; metabolism ; Sphingomonas ; metabolism

The aromatic-ring-hydroxylating dioxygenase is a key enzyme that initiates the biodegradation of polycyclic aromatic hydrocarbons in bacteria. In the present study, a novel dioxygenase sequence was cloned from Terrabacter sp. FLO using a genome walking method. The dioxygenase was cloned into pET17 and actively expressed in E.coli BL21 (DE3) in co-expression with electron transfer chain proteins. The recombinant dioxygenase was found to transform phenanthrene, fluorene, pyrene and fluoranthene into the cis-dihydrodiol metabolites.
Actinomycetales ; enzymology ; genetics ; Bacterial Proteins ; genetics ; metabolism ; Biodegradation, Environmental ; Cloning, Molecular ; Dioxygenases ; genetics ; metabolism ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; genetics ; metabolism ; Fluorenes ; metabolism ; Hydroxylation ; Molecular Sequence Data ; Phenanthrenes ; metabolism ; Polycyclic Aromatic Hydrocarbons ; metabolism ; Pyrenes ; metabolism ; Recombinant Proteins ; metabolism

OBJECTIVETo detect the expression of the plateau adaptablity gene(EPAS1, EGLN1 and PPARα) and proteins(HIF-2, PHD2 and PPARα) in rats blood, heart, liver, lung and kidney tissue after the rats exposed to high altitude.

METHODSThe Wistar rats were randomly divided into plain group(Shanghai, 55 m), acute exposure to high altitude 3400 m group, acute exposure to high altitude 4300 m group. Blood and organs of rats were collected in 1, 3, 5 days after arrival. Real time PCR and ELISA were used to compare the expression of plateau adaptablity gene and related protein between plain group and high altitude exposure groups.

RESULTSThe count of red blood cells, hemoglobin and HCT in high altitude 4300 m were higher than those in plain group. Compared with plain group, the expression of EPAS1 gene in blood, heart, liver and kidney tissue of rats at high altitude increased obviously(all P<0.05); the expression of EGLN1 in the heart, liver, brain and kidney increased, and PPARα gene in the heart, liver and kidney increased(all P<0.05). Compared with plain group, the expression of HIF-2 protein increased significantly at high altitudes in the liver, brain and kidney tissues. PHD2 and PPARα increased in the heart, liver and kidney.

CONCLUSIONPlateau adaptive genes(EPAS1, EGLN1 and PPARα) and protein(HIF-2, PHD2 and PPARα) differed in different altitude and different organizations. They might be used as target markers of plateau hypoxia.

Adaptation, Physiological ; Altitude ; Animals ; Basic Helix-Loop-Helix Transcription Factors ; metabolism ; Brain ; China ; Heart ; Hypoxia ; Hypoxia-Inducible Factor-Proline Dioxygenases ; metabolism ; Kidney ; Liver ; Lung ; PPAR alpha ; metabolism ; Procollagen-Proline Dioxygenase ; metabolism ; Rats ; Rats, Wistar

OBJECTIVETo study the acireductone dioxygenase (designated as SmARD) gene of Salvia miltiorrhiza through bioinformatics and characterization of its tissue expression and response expression on stress in shoot.

METHODSmARD gene was obtained by sequencing cDNA library constructed by us. BLAST was used for alignment, ORF finder software was applied to find open reading frame, prosite was used to analyze the protein characterization. Semi-quantitative RT-PCR was used to detect the gene expression level.

RESULTThe full -length cDNA of SmRAD was 688 bp long with a 591 bp ORF (open reading frame) that putatively encoded a polypeptide of 196 amino acids; with a predicted molecular mass of 23.27 kDa. The deduced amino acid sequence of SmRAD of gene shared high homology with other known RADs. Semi-quantitative RT-PCR analysis indicated that SmRAD was constitutively expressed in roots, stems, flower and leaves of S. miltiorrhiza, with the high expression in roots. In addition, SmRAD expression level under different stress condition was also analyzed in root, including signaling components for plant defence responses, such as methyl jasmonate, salicylic acid and ABA, as well as drought, cold and salt abiotic stress. The expression of SmRAD was suppressed by water deficit treatment for 3 d, 150 mmol x L(-1) NaCl, 4 degrees C cold and 100 mmol x L(-1) ABA treatment for 1 d, but induced by 100 mmol x L(-1) MJ and 10 mmol x L(-1) ETH.

CONCLUSIONA novel SmARD gene was cloned from S. miltiorrhiza. This study will enable us to further understand the role of SmARD in the defense response under different abiotic stress and in synthesis of active cmpounds in S. miltiorrhiza at molecular level.

Amino Acid Sequence ; Cloning, Molecular ; Dioxygenases ; genetics ; metabolism ; Gene Expression Regulation, Plant ; Molecular Sequence Data ; Phylogeny ; Plant Roots ; genetics ; metabolism ; Salvia miltiorrhiza ; genetics ; metabolism ; Sequence Alignment ; Sequence Analysis, DNA ; Sequence Homology, Amino Acid ; Stress, Physiological

Prolyl-4-hydroxylase domain (PHDs) family is one of the most important regulatory factors in hypoxic stress. PHD2 plays a critical role in cells and tissues adaptation to the low oxygen environment. Its hydroxylation activity regulates the stability and transcriptional activity of the hypoxia-inducible factor 1 (HIF-1), which is the key factor in response to hypoxic stress. Subsequently, PHD2 acts as an important factor in oxygen homeostasis. Studies have shown that PHD2, through its regulation on HIF-1, plays an important role in the post-ischemic neovascularization. Furthermore, under hypoxic condition, PHD2 also regulates other pathways that positively regulate angiogenesis factors HIF-1 independently. Moreover, recently, several evidences have also shown that PHD2 also affects tumor growth and metastasis in a tumor microenvironment. Based on these facts, PHD2 have been considered as a potential therapeutic target both in treating ischemic diseases and tumors. Here, we review the molecular regulation mechanism of PHD2 and its physiological and pathological functions. We focus on the role of PHD2 in both therapeutic angiogenesis for ischemic disease and tumor angiogenesis, and the current progress in utilizing PHD2 as a therapeutic target.
Animals ; Humans ; Hydroxylation ; Hypoxia-Inducible Factor 1 ; metabolism ; Hypoxia-Inducible Factor-Proline Dioxygenases ; antagonists & inhibitors ; physiology ; Neoplasms ; blood supply ; metabolism ; pathology ; therapy ; Neovascularization, Pathologic ; metabolism ; pathology ; Tumor Microenvironment ; Vascular Diseases ; pathology ; therapy

Humans ; Hypoxia-Inducible Factor-Proline Dioxygenases ; metabolism ; Ki-67 Antigen ; metabolism ; MicroRNAs ; metabolism ; Neoplasm Grading ; Neoplasm Staging ; Neprilysin ; metabolism ; Neuroendocrine Tumors ; classification ; diagnosis ; metabolism ; pathology ; surgery ; PAX8 Transcription Factor ; Paired Box Transcription Factors ; metabolism ; Pancreatic Neoplasms ; classification ; diagnosis ; metabolism ; pathology ; surgery ; Prognosis ; Tumor Suppressor Proteins ; metabolism

OBJECTIVETo investigate the protective effect of Crocin against hypoxia damage of cardiac myocytes of neonatal rats and the regulation of HIF-1 and prolyhydroxylase (PHDs).

METHODSA model of CoCl2 simulated hypoxia damage was established in primary cultural myocardial cell. Expression levels of HIF-1alpha, VEGF, iNOS, as well as PHD1, 2, 3 protein in myocardial cells were detected by Western blot.

RESULTSCompared with CoCl2 group, the viability of myocardial cell was significantly increased after treated 24 h at 10(-5)mol/L Crocin (P < 0.01), HIF-1alpha, VEGF and iNOS were expressed higher than those in Crocin + CoCl2 group (P < 0.01), the expression of PHD2 was significantly increased (P < 0.01), while the expression of PHD3 was remarkably reduced in Crocin + CoCl2 Group (P < 0.01).

CONCLUSIONCrocin has better protective effect on hypoxic damage of myocardial cell. The mechanisms of protective effect of Crocin may be related to the activation of HIF-1-mediated pathway of the hypoxia response. PHDs may be involved in the pathophysiology regulated process of myocardial cells.

Animals ; Carotenoids ; pharmacology ; Cell Hypoxia ; drug effects ; Cells, Cultured ; Homeodomain Proteins ; metabolism ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Hypoxia-Inducible Factor-Proline Dioxygenases ; metabolism ; Myocytes, Cardiac ; drug effects ; metabolism ; Nitric Oxide Synthase Type II ; metabolism ; Procollagen-Proline Dioxygenase ; metabolism ; Rats ; Rats, Sprague-Dawley ; Vascular Endothelial Growth Factor A ; metabolism