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1.
Front Public Health ; 12: 1368178, 2024.
Article En | MEDLINE | ID: mdl-38694975

Background: Shift work can disrupt sleep quality and gut health. Nurses and midwives constitute approximately half of the global healthcare shift-working workforce. Our previous study revealed that most midwives were experiencing suboptimal health conditions, characterized by poor sleep quality and a high prevalence of gastrointestinal diseases. The gut-brain axis theory highlights the potential interplay between sleep quality and gut health. However, limited research focuses on this relationship among midwives. Methods: A cross-sectional survey included 2041 midwives from 87 Chinese hospitals between March and October 2023. Participants completed standardized questionnaires assessing sleep quality, gut health, depression, anxiety, and work stress. Binary logistic regression analyzed factors associated with poor sleep, and multiple linear regression examined the influence of sleep quality on gut health. Results: Over 60% of midwives reported poor sleep, with many experiencing gastrointestinal disorders. We observed a bidirectional relationship between sleep quality and gut health among midwives. After multivariable adjustments, midwives with higher gut health scores were more likely to experience poor sleep quality (odds ratio = 1.042, 95% confidence interval = 1.03-1.054). Conversely, midwives with higher sleep quality scores were also more likely to have poor gut health (ß = 0.222, 95% confidence interval = 0.529-0.797). These associations remained robust across sensitivity analyses. Furthermore, depression, anxiety, and work stress significantly affected both sleep quality and gut health among midwives. Conclusion: This study enhances our understanding of the intricate relationship between sleep quality and gut health among midwives. Poor gut health was associated with a higher risk of poor sleep, and vice versa. To improve the overall wellbeing of midwives, the findings emphasize the importance of addressing poor sleep quality and promoting gut health through maintaining a healthy diet, lifestyle, and good mental health. Further studies are needed to confirm our findings and clarify the underlying mechanisms.


Sleep Quality , Humans , Cross-Sectional Studies , China/epidemiology , Adult , Female , Prevalence , Surveys and Questionnaires , Middle Aged , Midwifery/statistics & numerical data , Gastrointestinal Diseases/epidemiology , Sleep Wake Disorders/epidemiology
2.
Front Psychiatry ; 14: 1213025, 2023.
Article En | MEDLINE | ID: mdl-37779621

Background: Female nurses have been considered as a vulnerable population in the context of mental health, due to the nature of their work, which can be stressful and emotionally taxing. Understanding the relationship between depressive symptoms and quality of work life (QWL) can contribute to improving mental health and job performance. However, limited studies have focused on the effect of depressive symptoms on QWL in female nurses. Objectives: The present study aimed to assess the effect of depressive symptoms on female nurses' QWL using propensity score matching (PSM). Methods: A cross-sectional, online study using convenience sampling was conducted among 1,401 female nurses in China. PSM was used to minimize the impact of potential confounders between no depressive symptoms and depressive symptoms. Stepwise multiple linear regression analyses were performed on the PSM samples to explore the effects of depressive symptoms on the QWL. Results: The results revealed there were 33.5% of the female nurses reported depressive symptoms before PSM. And female nurses in this study had a moderate level of QWL before PSM (122.11 ± 18.15), which remained steady after PSM (118.33 ± 18.04). After PSM, the final sample contained 864 female nurses. Stepwise multiple linear regression results indicated that depressive symptoms were the most strongly associated with QWL (ß = -0.454, p < 0.001). Conclusion: This study highlights the importance of developing mental health plans and psychological interventions for female nurses to maintain mental health and QWL, which is critical to the nursing workforce's sustainability.

3.
BMC Nurs ; 22(1): 42, 2023 Feb 15.
Article En | MEDLINE | ID: mdl-36788572

AIMS: To examine the mediating effect of resilience between social support and compassion fatigue among intern nursing and midwifery students during COVID-19. BACKGROUND: Compassion fatigue has become exceedingly common among intern nursing and midwifery students, especially during the COVID-19 pandemic. Social support and resilience can help intern nursing and midwifery students control their negative emotions, reduce compassion fatigue, and increase their well-being. However, the mediating effect of resilience between social support and compassion fatigue remains unclear. DESIGN: A multicentre cross-sectional survey. METHODS: A total of 307 intern nursing and midwifery students were recruited from November 2020 to February 2021 in tertiary grade A hospitals in China. Structural equation modelling was applied to analyse the mediating effects of resilience between social support and compassion fatigue. The Social Support Rating Scale, the 10-item Connor-Davidson Resilience Scale, and the Chinese version of the Compassion Fatigue Short Scale were used to collect data. The hypothetical path model was tested by using IBM SPSS version 26.0 and AMOS version 26.0 software. RESULTS: Intern nursing and midwifery students had moderate compassion fatigue. Social support positively affected resilience (ß = 0.514, p < 0.01). Social support negatively affected compassion fatigue (ß = - 0.310, p < 0.01), while resilience negatively affected compassion fatigue (ß = - 0.283, p < 0.01). Resilience played a mediating role between social support and compassion fatigue. CONCLUSION: Social support can directly affect the compassion fatigue of intern nursing and midwifery students during COVID-19 and indirectly through resilience. Stronger resilience can reduce compassion fatigue. Accordingly, resilience-based interventions should be developed to reduce compassion fatigue.

4.
Zhongguo Zhen Jiu ; 41(6): 671-4, 2021 Jun 12.
Article Zh | MEDLINE | ID: mdl-34085487

In the guidance of qijie (qi street, path of qi ) theory, the thought on diagnosis and treatment with acupuncture and moxibustion for facial spasm is analyzed. Qijie theory is a summary of the horizontal distribution rule of human body and the conclusion of the characteristics of function and indication in a certain area. In terms of spatial location and functional characteristics, facial spasm is related to "head qijie". In treatment with acupuncture and moxibustion, the local acupoints are predominated. Additionally, the distal acupoints are selected based on the characteristics of qijie in pathological condition, "qijie is unblocked even though the obstruction occurs in minor collateral"; and the acupoints for calming the mind are combined based on the relationship between head qijie and the brain function, aiming to regulating the body, qi and spirit. Regarding the techniques of acupuncture and moxibustion, align with the spatial location and hierarchical location of disease, the depth of filiform needle insertion and needling stimulation are specified and the palpation on the local meridians and acupoints are emphasized before acupuncture specially.


Acupuncture Therapy , Acupuncture , Meridians , Moxibustion , Acupuncture Points , Humans , Spasm
5.
Int J Syst Evol Microbiol ; 59(Pt 4): 719-23, 2009 Apr.
Article En | MEDLINE | ID: mdl-19329595

Strain NX02(T), a Gram-negative, non-spore-forming, rod-shaped bacterium, was isolated from soil, and its taxonomic position was investigated using a polyphasic approach. Chemotaxonomic analysis revealed that strain NX02(T) possessed Q-10 as the predominant ubiquinone, sym-homospermidine as the major polyamine and C(18 : 1)omega7c, C(16 : 0) and C(14 : 0) 2-OH as the major fatty acids. The main polar lipids were sphingoglycolipid, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine and an unidentified glycolipid. The DNA G+C content was 66.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain NX02(T) belongs to the alpha-4 subgroup of the Proteobacteria, exhibiting the highest sequence similarity with respect to Sphingomonas azotifigens NBRC 15497(T) (95.9 %), Sphingomonas pituitosa DSM 13101(T) (95.8 %) and Sphingomonas dokdonensis KCTC 12541(T) (95.8 %). On the basis of these results, strain NX02(T) represents a novel species of the genus Sphingomonas sensu stricto, for which the name Sphingomonas sanxanigenens sp. nov. is proposed. The type strain is NX02(T) (=DSM 19645(T) =CGMCC 1.6417(T)).


Soil Microbiology , Sphingomonas/classification , Sphingomonas/isolation & purification , Bacterial Typing Techniques , Base Composition , Cluster Analysis , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Fatty Acids/analysis , Molecular Sequence Data , Phospholipids/analysis , Phylogeny , Polyamines/analysis , Quinones/analysis , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Sequence Homology, Nucleic Acid , Sphingomonas/chemistry , Sphingomonas/genetics
6.
Mar Pollut Bull ; 56(10): 1714-8, 2008 Oct.
Article En | MEDLINE | ID: mdl-18778839

A novel bacterium T7-2 was isolated from the oil-polluted sea-bed mud of Bohai Sea, northern China, which can degrade diesel oil at 15 degrees C. This bacterium was identified as a strain of Rhodococcus erythropolis according to its 16S rDNA gene. In order to enhance degradation efficiency, a five-level, three-factor central composite design was employed to optimize the nutrition supplied to artificial seawater. The results indicate that a supplement of 2.53 g (NH(4))(2)SO(4)L(-1), 2.75 g Na(2)HPO(4)L(-1) and 0.01 g yeast extract L(-1) to artificial seawater increases the degradation rate from 12.61% to 75% within 7d.


Biodegradation, Environmental , Gasoline , Rhodococcus/metabolism , Culture Media/chemistry , Geologic Sediments/microbiology , Oceans and Seas , Rhodococcus/classification , Rhodococcus/isolation & purification , Seawater/chemistry
7.
Huan Jing Ke Xue ; 29(2): 462-8, 2008 Feb.
Article Zh | MEDLINE | ID: mdl-18613521

It is a brand-new method to isolate functional bacteria from high temperature petroleum reservoirs according to the sequence information obtained from PCR-DGGE patterns. Three-set primers of 16S rDNA high variable region, V3, V8, V9, were compared. The results showed that more microbial diversity information could be obtained from the PCR product of V9 region. Sequence analysis indicated that the dominant bacteria in the petroleum reservoir had high sequence similarity with bacteria from alpha, beta, gamma-Proteobacterias and Bacilli from the GenBank database. According to the sequences information, multi-cultivation technology including enrichment cultivation, special cultivation and direct cultivation methods were employed, and finally, five strains (three strains by traditional methods) were isolated from oil-water samples. Among them, three thermophilic hydrocarbon-degrading bacteria, which belonged to Bacillus sp., Geobacillus sp. and Petrobacter sp., respectively, could grow well under 55 degrees C in obligate anaerobic condition. The crude oil could be utilized by these strains with the degradation rate of 56.5%, 70.01% and 31.78% respectively along with the viscosity reduction rate of 40%, 54.55% and 29.09%, meanwhile the solidify points of crude oil were reduced by 3.7, 5.2 and 3.1 degrees C. Therefore, the combination of sequence information from PCR-DGGE and altering cultivation conditions is an available novel method to isolate more functional microorganisms which could be utilized for microbial enhanced oil recovery.


Bacillus/isolation & purification , Geobacter/isolation & purification , Hot Temperature , Petroleum/microbiology , Polymerase Chain Reaction/methods , Bacillus/genetics , Bacillus/metabolism , Bacteria/classification , Bacteria/genetics , Bacteria/metabolism , Electrophoresis, Gel, Pulsed-Field/methods , Geobacter/genetics , Geobacter/metabolism , Petroleum/metabolism , Phylogeny , Proteobacteria/genetics , Proteobacteria/isolation & purification , Proteobacteria/metabolism , RNA, Ribosomal, 16S/genetics , Reproducibility of Results
8.
Neurosci Lett ; 441(1): 50-5, 2008 Aug 15.
Article En | MEDLINE | ID: mdl-18586400

The atypical serine/threonine protein kinase, a mammalian target of rapamycin (mTOR), is believed to be essential to the regulation of cell growth and the functions of the central nervous system. By using calcium imaging and patch-clamping techniques to study the role of this signaling pathway in the activity of cultured hippocampal neurons, we found that rapamycin significantly reduces the spontaneous activities of network neurons as well as the efficacy of synaptic transmission through insulin-mTOR signaling pathway. Our study sheds light on understanding the role of mTOR signaling pathway in controlling the information processing of network neurons.


Action Potentials/drug effects , Calcium Signaling/drug effects , Calcium/metabolism , Enzyme Inhibitors/pharmacology , Hippocampus/cytology , Neurons/drug effects , Sirolimus/pharmacology , Action Potentials/physiology , Animals , Calcium Signaling/physiology , Cells, Cultured , Dose-Response Relationship, Drug , Dose-Response Relationship, Radiation , Electric Stimulation , Embryo, Mammalian , Neurons/physiology , Patch-Clamp Techniques , Rats , Time Factors
9.
Biotechnol Lett ; 30(10): 1759-64, 2008 Oct.
Article En | MEDLINE | ID: mdl-18516503

Substituted benzothiophenes (BTs) and dibenzothiophenes (DBTs) remain in diesel oil following conventional desulfurization by hydrodesulfurization. A mixture of washed cells (13.6 g dry cell wt l(-1)) of Rhodococcus erythropolis DS-3 and Gordonia sp. C-6 were employed to desulfurize hydrodesulfurized diesel oil; its sulfur content was reduced from 1.26 g l(-1) to 180 mg l(-1), approx 86% (w/w) of the total sulfur was removed from diesel oil after three cycles of biodesulfurization. The average desulfurization rate was 0.22 mg sulfur (g dry cell wt)(-1) h(-1). A bacterial mixture is therefore efficient for the practical biodesulfurization of diesel oil.


Gasoline , Gordonia Bacterium/metabolism , Rhodococcus/metabolism , Sulfur/metabolism , Substrate Specificity
10.
Appl Environ Microbiol ; 74(4): 971-6, 2008 Feb.
Article En | MEDLINE | ID: mdl-18165370

Dibenzothiophene (DBT) and its derivatives can be microbially desulfurized by enzymes DszC, DszA, and DszB, which are encoded by the operon dszABC and contribute to the conversion in tandem. We investigated the expression characteristics of the dsz operon. Our results revealed that the levels of transcription and translation of dszA, dszB, and dszC decreased according to the positions of the genes in the dsz operon. Furthermore, the translation of dszB was repressed by an overlapping structure in the dsz operon. In order to get better and steady expression of the Dsz enzymes and optimize the metabolic flux of DBT, we rearranged the dsz operon according to the catalytic capabilities of the Dsz enzymes and expressed the rearranged dsz operon, dszBCA, in Rhodococcus erythropolis. After rearrangement, the ratio of dszA, dszB, and dszC mRNAs in the cells was changed, from 11:3.3:1 to 1:16:5. Western blot analysis revealed that the levels of expression of dszB and dszC had been enhanced but that the expression of dszA had decreased. The desulfurization activity of resting cells prepared from R. erythropolis DRB, which carried the rearranged dsz operon, was about 12-fold higher than that of resting cells of R. erythropolis DRA, which carried the original operon in a similarly constructed vector.


Gene Expression Regulation, Enzymologic/physiology , Rhodococcus/metabolism , Sulfur/metabolism , Thiophenes/metabolism , Blotting, Western , Electroporation , Genetic Engineering , Operon/genetics , Oxygenases/genetics , Oxygenases/metabolism , Rhodococcus/genetics
11.
Huan Jing Ke Xue ; 29(11): 3166-71, 2008 Nov.
Article Zh | MEDLINE | ID: mdl-19186822

Gordonia sp. C-6 can desulfurize benzothiophene (BT) as the pathway similar to the "4S" pathway of dibenzothiophene (DBT)-desulfurizing, but the strain can not grow with DBT as the sole sulfur source. At current, there were not related reports on BT-desulfurizing genes at home or abroad. The DBT-desulfurizing genes of Rhodocossus erythropolis DS-3, dszA, dszB, dszC and dszABC were introduced into Gordonia sp. C-6 respectively using a Rhodococcus-E. coli shuttle vector, to construct new recombinant strains Gordonia sp. CRA, Gordonia sp. CRB, Gordonia sp. CRC and Gordonia sp. CRABC, the enzyme activities of which was respectively 76.8 micromol x (g x h)(-1), 51.6 micromol x (g x h)(-1) and 62.4 micromol x (g x h)(-1), increasing by 1.5 times compared with 35.2 micromol x (g x h)(-1), 21.3 micromol x (g x h)(-1) and 25.5 micromol x (g x h)(-1) of wild strain Rhodocossus erythropolis DS-3. Of the recombinant strains, only recombinant strains Gordonia sp. CRC with DszC and Gordonia sp. CRABC with DszABC exhibite significant growth with DBT as the sole sulfur source, Gordonia sp. CRA with DszA and Gordonia sp. CRB with DszB could not live with DBT as the sole sulfur source. The results show that, DBT monoxygenase and BT monoxygenase, catalyzed the first two steps of DBT and BT oxidation, respectively, are the key enzymes responsible for substrate-recognition, however, the enzymes catalyzed the last two steps have the similar substrate specificity. The active sites of the two monoxygenase could be predicted by comparing with the sequence differences of their amino acids.


Gordonia Bacterium/genetics , Oxidoreductases/metabolism , Rhodococcus/genetics , Thiophenes/metabolism , Biodegradation, Environmental , Gordonia Bacterium/enzymology , Oxygenases/metabolism , Rhodococcus/enzymology , Transformation, Bacterial
12.
Huan Jing Ke Xue ; 29(12): 3554-60, 2008 Dec.
Article Zh | MEDLINE | ID: mdl-19256400

A thermophilic Geobacillus strain DM-2 from a deep-subsurface oil reservoir was investigated on its capability of degrading crude oil under various conditions as well as its characters on degrading hydrocarbons in optimal conditions. The results showed that Geobacillus strain DM-2 was able to degrade crude oil under anoxic wide-range conditions with pH ranging from 4.0 to 10.0, high temperature in the range of 45-70 degrees C and saline concentration ranging from 0.2% to 3.0%. Furthermore, the optimal temperature and pH value for utilizing hydrocarbons by the strain were 60 degrees C and 7.0, respectively. Under such optimal conditions, the strain utilized liquid paraffine emulsified by itself as its carbon source for growth; further analysis by gas chromatography (GC) and infrared absorption spectroscopy demonstrated that it was able to degrade n-alkanes (C14-C30), branched-chain alkanes and aromatic hydrocarbons in crude oil and could also utilize long-chain n-alkanes from C16 to C36, among of which the degradation efficiency of C28 was the highest, up to 88.95%. One metabolite of the strain oxidizing alkanes is fatty acid.While utilizing C16 as carbon source for 5 d, only one fatty acid-acetic acid was detected by HPLC and MS as the product, with the amount of 0.312 g/L, which indicated that it degraded n-alkanes with pathway of inferior terminal oxidation,and then followed by a beta-oxidation pathway. Due to its characters of efficient emulsification, high-performance degradation of hydrocarbons and fatty-acid production under high temperature and anoxic condition, the strain DM-2 may be potentially applied to oil-waste treatment and microbial enhanced heavy oil recovery in extreme conditions.


Alkanes/metabolism , Bacillaceae/metabolism , Hydrocarbons/metabolism , Bacillaceae/classification , Bacillaceae/isolation & purification , Biodegradation, Environmental
13.
Huan Jing Ke Xue ; 28(9): 2101-5, 2007 Sep.
Article Zh | MEDLINE | ID: mdl-17990565

A low-temperature hydrocarbon-degrading strain T7-2 was isolated from sea-mud of Bohai polluted area and identified as Rhodococcus erythropolis, which could use diesel oil as carbon source. The optimal temperature and pH for the strain utilizing ethanol was 15 degrees C and 7.8, and the optimal concentration of ethanol and the seed culture was 0.5% and 10(8) CFU/mL, respectively. Inoculated to artificial seawater which was added (NH4)2SO5 2.64 g/L, Na2HPO4 2.5 g/L and yeast extract 0.015 g/L after 7 days of culture at the temperature of 15 degrees C, the rate of degradation was 73.2%. The strain could degrade a large range of n-alkane from C12 to C36.


Carbon/metabolism , Gasoline , Hydrocarbons/metabolism , Rhodococcus/isolation & purification , Biodegradation, Environmental , Cold Temperature , Hydrocarbons/chemistry , Hydrogen-Ion Concentration , Rhodococcus/metabolism , Seawater/microbiology
14.
Biosci Biotechnol Biochem ; 71(4): 849-54, 2007 Apr.
Article En | MEDLINE | ID: mdl-17420595

Dibenzothiophene (DBT) and its derivatives can be microbially desulfurized by Dsz enzymes. We investigated the expressional characteristics of the dsz operon. The result revealed that the ratio of mRNA quantity of dszA, dszB, and dszC was 11:3.3:1; however, western blot analysis indicated that the expression level of dszB is far lower than that of dszC. Gene analysis revealed that the termination codon of dszA and the initiation codon of dszB overlapped, whereas there was a 13-bp gap between dszB and dszC. In order to get a better, steady expression of DszB, we removed this structure by overlap polymerase chain reaction (PCR) and expressed the redesigned dsz operon in Rhodococcus erythropolis. The desulfurization activity of resting cells prepared from R. erythropolis DR-2, which held the redesigned dsz operon, was about five-fold higher than that of R. erythropolis DR-1, which held the original dsz operon.


Oxygenases/genetics , Rhodococcus/enzymology , Rhodococcus/genetics , Sulfur/metabolism , Thiophenes/metabolism , Blotting, Western , Operon/genetics , Plasmids/genetics , Protein Engineering , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Reverse Transcriptase Polymerase Chain Reaction
15.
Huan Jing Ke Xue ; 27(6): 1181-5, 2006 Jun.
Article Zh | MEDLINE | ID: mdl-16921958

A benzothiophene-desulfurizing strain was isolated and identified as Gordonia sp. C-6, which could degrade benzothiophene (BT) in a way analogous to the 4S pathway. It was found strain C-6 had the ability to grow in KT-BT medium whose sole source of sulfur was BT or its derivatives, whereas it couldn't grow well in a medium with DBT and its derivatives as the sole source of sulfur, the desulfurized product was identified as 2-(2'-hydroxyphenyl) ethan-1-al or its isomer benzofuran by GC-MS analysis. Desulfurization activity of strain C-6 was investigated. About 0.15mmol/L(50%) BT was desulfurized by strain C-6 after it was incubated in KT-BT medium at 30 degrees C for 48h, the residual BT has volatilized during aerobic fermentation. The quantitative detection of the benzothiophene-desulfurizing products was established with o-hydroxyphenylacetic acid as standard compound, the standard curve was fitted by Matlab.


Gordonia Bacterium/isolation & purification , Gordonia Bacterium/metabolism , Sulfur/metabolism , Thiophenes/metabolism , Gordonia Bacterium/classification , Phylogeny , RNA, Ribosomal, 16S/genetics , Soil Microbiology
16.
Huan Jing Ke Xue ; 27(6): 1191-6, 2006 Jun.
Article Zh | MEDLINE | ID: mdl-16921960

Rhodococcus sp. PR-1 with high capability of demulsification on a surfactant-stabilized kerosene-water model emulsion was isolated from sewage of Dagang oil field. It could demulsify the model emulsion completely in 8 hours at 55 degrees C and had better demulsifying capability than chemical demulsifier DGF-01. The freezing-thawing and autoclaving had no effect on the process of demulsification, yet ultrasonic disposal and deal with organic solvent could inhibit its activity. A linear relationship, not the first order reaction that was used in some references, was observed between the percentage of demulsification and reaction time. The demulsifying capability of PR-1 was mainly resulted from the hydrophobic surfaces of microbial cells, which were characterized by the mycolic acids with the carbon-chain-length from 27 to 54. These results provide foundation for biological application on demulsifying crude oil emulsions in produced water of oil field.


Emulsifying Agents/metabolism , Petroleum/metabolism , Rhodococcus/isolation & purification , Rhodococcus/metabolism , Biodegradation, Environmental , Emulsions , Petroleum/microbiology , Sewage/microbiology
17.
Wei Sheng Wu Xue Bao ; 46(2): 275-9, 2006 Apr.
Article Zh | MEDLINE | ID: mdl-16736591

Biological dusulfurizaion of petroleum feedstocks and products may offer an attractive alternative to reduce sulfur oxide emissions that cause serious environmental pollution. Dibenzothiophene (DBT), a model of organic sulfur compound in petroleum, can be microbially desulfurized without degradation of the organic structure by 4S pathway. Three desulfurization enzymes (DszA, DszB and DszC) and flavin reductase (DszD) are involved in sulfur-specific DBT desulfurization. DszA and DszC are FMNH2-dependent monoxygenases, FMNH2 is provided from the freely diffusible FMNH2 pool in the cell, and is replenished by DszD. So, co-expression of the desulfurization enzymes and flavin reductase can enhance the rate of sulfur removal. In the present work two incompatible plasmids: pBADD and paN2 were constructed. The paN2 allows Escherichia coli to liberate the sulfur of DBT and DBTs and pBADD produces a flavin reductase. They were co-expressed in Escherichia coli B121 (DE3). The soluble products of DszA, DszB, DszC and DszD accounted for 7.6%, 3.5%, 3.1% and 18% of the total proteins in co-expressed system. The desulfurization rate of lysate of E. coli BL21- pBADD + paN2 is 12.03 micromol/(h x mg) Dsz protein and about 5.4-fold of that of E. coli BL2-paN2. Experiment were also conducted using resting cell with the 0.6 wt% DBT in n-hexadecane as model diesel oil. After 24 hours reaction, 0.42 mmol/L (about 84%) DBT was converted to 2-HBP by E. coli BL21- pBADD + paN2, however, there was only 0.08 mmol/L (about 16%) DBT was desulfurized by E. coli BL2-paN2. The maximum desulfurization rate of E.coli BL21-pBADD + paN2 is about 67 micromol/h. The result shows that DszD enhances the rate of 2-HBP production when co-expressed in vivo with the desulfurization enzymes.


Bacterial Proteins/genetics , Escherichia coli/genetics , Gene Expression , Oxidoreductases/genetics , Oxygenases/genetics , Plasmids/genetics , Rhodococcus/enzymology , Bacterial Proteins/metabolism , Biodegradation, Environmental , Escherichia coli/metabolism , Oxidoreductases/metabolism , Oxygenases/metabolism , Thiophenes/metabolism
18.
Extremophiles ; 10(4): 347-56, 2006 Aug.
Article En | MEDLINE | ID: mdl-16604274

A thermophilic Bacillus strain NG80-2 growing within the temperature range of 45-73 degrees C (optimum at 65 degrees C) was isolated from a deep subterranean oil-reservoir in northern China. The strain was able to utilize crude oil and liquid paraffin as the sole carbon sources for growth, and the growth with crude oil was accompanied by the production of an unknown emulsifying agent. Further examination showed that NG80-2 degraded and utilized only long-chain (C15-C36) n-alkanes, but not short-chain (C8-C14) n-alkanes and those longer than C40. Based on phenotypic and phylogenic analyses, NG80-2 was identified as Geobacillus thermodenitrificans. The strain NG80-2 may be potentially used for oily-waste treatment at elevated temperature, a condition which greatly accelerates the biodegradation rate, and for microbial enhancing oil recovery process.


Alkanes/chemistry , Alkanes/metabolism , Bacillus/classification , Bacillus/isolation & purification , Bacillus/genetics , Mineral Oil/metabolism , Petroleum/metabolism , Phylogeny , Time Factors
19.
Wei Sheng Wu Xue Bao ; 46(1): 104-10, 2006 Feb.
Article Zh | MEDLINE | ID: mdl-16579475

A strain Fds-1, which can specially break the C-S bond of dibenzothiophene (DBT) and convert DBT into 2-hydrobenzophene (2-HBP), was screened out from soil soaked with crude oil and identified as Bacillus subtilis. Both Gibb's reaction and GC-MS analysis proved that this bacterium could remove sulfur of DBT by "4S" pathway. The optimal temperature of desulfurization is 30 degrees C. At this temperature, Fds-1 could remove 0.5mmol/L organ sulfur of DBT in 72h, so it is suitable to decrease the sulfur content of diesel oil. The final product named 2-HBP is a water-soluble compound. This research focused on the desulfurization methods of diesel oil using Fds-1 resting cells. The results showed Fds-1 exhibited strong degradation capacity of DBT and alkyl-DBT in diesel oil. Experiments of two diesel oil samples for desulfurization proved that Fds-1 did not break the carbon-carbon backbone and the calorific value of diesel oil was reserved. Therefore strain Fds-1 is significant to deep biodesulfurisation comparing the hydro-desulfurization of diesel oil.


Bacillus subtilis/genetics , Soil Microbiology , Thiophenes/metabolism , Bacillus subtilis/isolation & purification , Bacillus subtilis/metabolism , Biodegradation, Environmental , Petroleum/metabolism , Polymerase Chain Reaction , RNA, Ribosomal, 16S
20.
Wei Sheng Wu Xue Bao ; 46(6): 1023-7, 2006 Dec.
Article Zh | MEDLINE | ID: mdl-17302175

The amount of organic nitrides contained in fuel oil is smaller than the one of organic sulfur compounds, but the existence of them is enough to affect the invariability of oil product greatly , and has a big effect on the color of oil. They also contribute to catalyst poisoning during the refining of crude oil, thus reducing the catalyzing rate of the catalyst and increasing process costs. Further more, some nitrogen organic compounds possess mutagenic and toxic activities. The combustion of these contaminants form nitrogen oxides (NOx), releasing of which to the air will cause the formation of acid rain and hence to air pollution. The classical hydroprocessing methods of nitrogen removal are costly and complicated, so the scientists are more and more interested in microbial denitrogenation. The aspects as follows are introduced, including the aromatic nitrogen compounds of fuel oil, the varieties of denitrogenation techincs, the classes of microbial denitrogenation and its biochemical pathways, molecular genetics developments of carbazole-degradative genes, and our opinion of the research direction in the future.


Carbazoles/metabolism , Fuel Oils , Nitrogen/metabolism , Pseudomonas/metabolism , Biodegradation, Environmental
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