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1.
Artigo em Inglês | MEDLINE | ID: mdl-35685734

RESUMO

Background/Aim: Abnormal proliferation and migration of vascular smooth muscle cells is one of the main causes of atherosclerosis (AS). Therefore, the suppression of abnormal proliferation and migration of smooth muscle cells are the important means for the prevention and inhibition of AS. The clinical effects of Guanxinping (GXP) tablets and preliminary clinical research on the topic have proved that GXP can effectively treat coronary heart disease, but its underlying mechanism remains unclear. This study aimed to confirm the inhibitory effect of GXP on the abnormal proliferation of mouse aortic vascular smooth muscle (MOVAS) cells and to explore the underlying mechanism. Methods: MOVAS cells were divided into two major groups: physiological and pathological groups. In the physiological group, MOVAS cells were directly stimulated with GXP, whereas in the pathological group, the cells were stimulated by endothelin-1 (ET-1) before intervention by GXP. At the same time, atorvastatin calcium, which effectively inhibits the abnormal proliferation of MOVAS cells, was used in the negative control group. CCK8 assay, scratch test, ELISA, Western blotting, and immunofluorescence staining were performed to observe the proliferation and migration of MOVAS cells and the expression levels of related factors after drug intervention in each group. Results: In the physiological group, GXP had no significant effect on the proliferation and migration of MOVAS cells and the related factors. In the pathological group, a high dose of GXP reduced the abnormal proliferation and migration of MOVAS cells. Further, it reduced the expression levels of PI3K; inhibited the phosphorylation of Akt (protein kinase B); upregulated IκB-α levels; prevented nuclear factor kappa B (NF-κB) from entering the nucleus; downregulated the expression of interleukin 6 (IL6), IL-1ß, and iNOS; and upregulated the ratio of apoptosis-related factor Bax/Bcl-2. There was no significant difference between the high-dose GXP group and the atorvastatin calcium group (negative control group). Conclusion: Our findings revealed that GXP was able to inhibit the proliferation and migration of MOVAS cells by regulating the PI3K/Akt/NF-κB pathway.

2.
Metabolomics ; 18(6): 38, 2022 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-35687195

RESUMO

Functional gastrointestinal disorders (FGID) such as functional dyspepsia (FD) and irritable bowel syndrome (IBS) are highly prevalent and debilitating attributed to altered gut function and gut-brain interactions. FGID can be reliably diagnosed based upon the symptom pattern; but in the clinical setting FD or IBS a frequent diagnoses of exclusion after relevant structural causes of symptoms have been ruled out by appropriate testing. Thus far, there is no established biomarker for FGIDs. To address this limitation, we utilised multi-omics and chemometrics integration to characterise the blood plasma biochemistry in patients with IBS, FD, an overlap of FD/IBS, and controls using liquid chromatography-mass spectrometry (LC-MS) techniques.Cholesterol metabolism products Cholest-5,24-dien-3ß-ol, 3-O-ß-D-glucopyranoside, energy pathway metabolites, immunoglobulin-γ2 and immunoglobulin-κ, and carbonic anhydrase-1 proteins were particularly elevated in IBS. Furthermore, arginine and proline metabolisms, thyroid hormone synthesis, ferroptosis and, complementary and coagulation cascades were particularly upregulated in patients with IBS. Cer(d18:1/26:1(17Z)) and PI(14:0/22:1(11Z)) lipids were elevated in FD and FD-IBS but were depleted in IBS. Markers of central carbon metabolism and lipidome profiles allowed better discrimination and model predictability than metaproteome profile in healthy and FGID conditions.Overall, the multi-omics integration allowed the discrimination of healthy controls and FGID patients. It also effectively differentiated the biochemistry of FGID subtypes including FD, IBS and FD-IBS co-occurrence. This study points towards the possibility of multi-omics integration for rapid and high throughput analysis of plasma samples to support clinicians screen and diagnose patients with suspected FGIDs.


Assuntos
Dispepsia , Gastroenteropatias , Síndrome do Intestino Irritável , Arginina , Dispepsia/diagnóstico , Dispepsia/etiologia , Gastroenteropatias/complicações , Gastroenteropatias/diagnóstico , Humanos , Síndrome do Intestino Irritável/diagnóstico , Lipídeos , Metabolômica , Plasma , Prolina
3.
Vector Borne Zoonotic Dis ; 20(8): 580-585, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32301684

RESUMO

Coxiella burnetii is the causative agent of query fever (Q fever), and distributes broadly in environment. Livestock are identified as main reservoirs, which may infect people through their contaminative urine, feces, milk, and birth products. Wild animals can also be the potential carriers and transmitters of C. burnetii. To understand the geographic distribution and host species of C. burnetii in China, we investigated the prevalence of C. burnetii in hedgehogs (Erinaceus amurensis) in Hubei Province. Hedgehogs were tested for C. burnetii with PCR targeting three genes (com1, rrs, and icd) followed by multispacer sequence typing (MST). We found that 12.2% (5/41) hedgehogs were PCR positive for C. burnetii. MST revealed presence of two novel genotypes and phylogenetic analysis revealed that the strains were similar to a group of isolates from chronic Q fever patients and mammals. This study showed that C. burnetii are highly prevalent in hedgehogs in Hubei Province in central China, suggesting that hedgehogs may play an important role in the ecology and transmission of C. burnetii to humans because it is captured and used as traditional medicine in China.


Assuntos
Coxiella burnetii/isolamento & purificação , Ouriços/microbiologia , Febre Q/veterinária , Animais , China/epidemiologia , Coxiella burnetii/classificação , Coxiella burnetii/genética , DNA Bacteriano , Genótipo , Filogenia , Reação em Cadeia da Polimerase , Prevalência , Febre Q/epidemiologia
4.
World J Stem Cells ; 12(12): 1576-1590, 2020 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-33505601

RESUMO

BACKGROUND: Synaptophysin plays a key role in synaptic development and plasticity of neurons and is closely related to the cognitive process of Alzheimer's disease (AD) patients. Exogenous neural stem cells (NSCs) improve the damaged nerve function. The effects of Sanjiao acupuncture on cognitive impairment may be related to the regulation of the NSC microenvironment. AIM: To explore the anti-dementia mechanism of acupuncture by regulating the NSC microenvironment. METHODS: NSCs were isolated from pregnant senescence-accelerated mouse resistant 1 (SAMR1) mice, labeled with BrdU, and injected into the hippocampus of senescence-accelerated mouse prone 8 (SAMP8) mice. Eight-month-old senescence-accelerated mice (SAM) were randomly divided into six groups: SAMR1 (RC), SAMP8 (PC), sham transplantation (PS), NSC transplantation (PT), NSC transplantation with acupuncture (PTA), and NSC transplantation with non-acupoint acupuncture (PTN). Morris water maze test was used to study the learning and memory ability of mice after NSC transplantation. Hematoxylin-eosin staining and immunofluorescence were used to observe the his-topathological changes and NSC proliferation in mice. A co-culture model of hippocampal slices and NSCs was established in vitro, and the synaptophysin expression in the hippocampal microenvironment of mice was observed by flow cytometry after acupuncture treatment. RESULTS: Morris water maze test showed significant cognitive impairment of learning and memory in 8-mo-old SAMP8, which improved in all the NSC transplantation groups. The behavioral change in the PTA group was stronger than those in the other two groups (P < 0.05). Histopathologically, the hippocampal structure was clear, the cell arrangement was dense and orderly, and the necrosis of cells in CA1 and CA3 areas was significantly reduced in the PTA group when compared with the PC group. The BrdU-positive proliferating cells were found in NSC hippocampal transplantation groups, and the number increased significantly in the PTA group than in the PT and PTN groups (P < 0.05). Flow cytometry showed that after co-culture of NSCs with hippocampal slices in vitro, the synaptophysin expression in the PC group decreased in comparison to the RC group, that in PT, PTA, and PTN groups increased as compared to the PC group, and that in the PTA group increased significantly as compared to the PTN group with acupoint-related specificity (P < 0.05). CONCLUSION: Acupuncture may promote nerve regeneration and synaptogenesis in SAMP8 mice by regulating the microenvironment of NSC transplantation to improve the nerve activity and promote the recovery of AD-damaged cells.

5.
Int J Parasitol Parasites Wildl ; 10: 274-280, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31700790

RESUMO

Snakes are popular as food and traditional medicine in China. However, information about parasitic and bacterial infections in snakes from China is scarce. We investigated the prevalence of selected zoonotic agents including Cryptosporidium, Hepatozoon and Spirometra, in snakes in central China from June to October in 2018 by PCR amplification using parasite-specific primers. PCR amplification and DNA sequencing showed that 10.1% (15/149) of snakes were positive for Cryptosporidium spp., while 2.7% (4/149) were positive for Hepatozoon. Additionally, we found 36.9% (55/149) of snakes were infected with Spirometra erinaceieuropaei. The spargana burden per infected snake ranged from 1 to 26. BLAST and phylogenetic analysis of small subunit ribosomal RNA (SSU rRNA) gene and 60-kDa glycoprotein (gp60) gene showed that the parasites belonged to Cryptosporidium parvum genotype IIdA15G1, C. baileyi, C. serpentis and a Hepatozoon species. We conclude that intensively farmed snakes excrete C. parvum and C. baileyi oocysts due to ingestion of infected feeder animals, and that wild snakes in central China were commonly infected with S. erinaceieuropaei, suggesting that eating improperly cooked snakes could be risky to human health.

6.
Neural Regen Res ; 13(3): 541-548, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29623942

RESUMO

Sanjiao acupuncture and HuangDiSan can promote the proliferation, migration and differentiation of exogenous neural stem cells in senescence-accelerated mouse prone 8 (SAMP8) mice and can improve learning and memory impairment and behavioral function in dementia-model mice. Thus, we sought to determine whether Sanjiao acupuncture and HuangDiSan can elevate the effect of neural stem cell transplantation in Alzheimer's disease model mice. Sanjiao acupuncture was used to stimulate Danzhong (CV17), Zhongwan (CV12), Qihai (CV6), bilateral Xuehai (SP10) and bilateral Zusanli (ST36) 15 days before and after implantation of neural stem cells (5 × 105) into the hippocampal dentate gyrus of SAMP8 mice. Simultaneously, 0.2 mL HuangDiSan, containing Rehmannia Root and Chinese Angelica, was intragastrically administered. Our results demonstrated that compared with mice undergoing neural stem cell transplantation alone, learning ability was significantly improved and synaptophysin mRNA and protein levels were greatly increased in the hippocampus of mice undergoing both Sanjiao acupuncture and intragastric administration of HuangDiSan. We conclude that the combination of Sanjiao acupuncture and HuangDiSan can effectively improve dementia symptoms in mice, and the mechanism of this action might be related to the regulation of synaptophysin expression.

7.
Molecules ; 23(1)2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-29342935

RESUMO

The unprecedented early spring frost that appears as a cold stress adversely affects growth and productivity in tea (Camellia sinensis L.); therefore, it is indispensable to develop approaches to improve the cold tolerance of tea. Here, we investigated the effect of pretreatment with exogenous melatonin on the net photosynthetic rate, the maximum photochemical efficiency of PSII, chlorophyll content, lipid peroxidation, reactive oxygen species (ROS) accumulation, antioxidant potential, and redox homeostasis in leaves of tea plants following cold stress. Our results revealed that cold treatment induced oxidative stress by increasing ROS accumulation, which in turn affected the photosynthetic process in tea leaves. However, treatment with melatonin mitigated cold-induced reductions in photosynthetic capacity by reducing oxidative stress through enhanced antioxidant potential and redox homeostasis. This study provides strong evidence that melatonin could alleviate cold-induced adverse effects in tea plants.


Assuntos
Antioxidantes/farmacologia , Camellia sinensis/fisiologia , Resposta ao Choque Frio/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Melatonina/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Clorofila/metabolismo , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Fotossíntese/efeitos dos fármacos , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio , Chá
8.
Am J Alzheimers Dis Other Demen ; 31(5): 413-21, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-26993489

RESUMO

AIM: The aim of this study is to extend the molecular mechanism of Tong Luo Jiu Nao (TLJN) for Alzheimer's disease (AD), which is a modern Chinese formula that has been used to treat AD. METHODS: The senescence-accelerated mouse prone 8 strain (SAMP8) is one of the most appropriate models to study the mechanism that underlies AD. The levels of plasma amyloid ß (Aß) and the Aß deposits were measured using enzyme-linked immunosorbent assay and immunohistochemistry. Immunoblotting was used to observe the effect of TLJN on inflammatory mediator expression in an senescence-accelerated mouse model of AD. RESULTS: Our data showed that the TLJN-treated groups exhibited a reduction in plasma Aß levels and reduced Aß expression. Moreover, TLJN effectively attenuated Aß-induced activation of extracellular signal-regulated kinase and c-Jun N-terminal kinases and blocked changes in inflammatory mediator expression. CONCLUSION: These data suggest that TLJN might have protective effects and could potentially act to attenuate inflammatory stress in the pathogenesis of AD.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Modelos Animais de Doenças , Medicamentos de Ervas Chinesas/administração & dosagem , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/sangue , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática/métodos , Inflamação , Camundongos
9.
Artigo em Inglês | MEDLINE | ID: mdl-26074994

RESUMO

We analyzed the effects of a traditional Chinese medicine, Qizhi Jiangtang Jiaonang (QJJ), on insulin resistance (IR) in vitro. After an in vitro model of IR was established by treating human liver cancer cells (HepG2 cells) with palmitic acid, the cells were then treated with various concentrations of QJJ. Treatment with 400 µM palmitic acid for 24 h induced IR in HepG2 cells. The survival rate for HepG2 cells in the IR group was significantly lower than that of the untreated control group (P < 0.001); however, QJJ restored HepG2 cell survival (P < 0.001). As compared with HepG2 cells in the IR group, QJJ at all doses analyzed significantly increased glucose consumption (all P < 0.05). Moreover, treatment with all the QJJ doses significantly reduced the mean intracellular reactive oxygen species levels as compared with the IR group (all P < 0.05). Furthermore, high-dose QJJ reduced both TNF-α and IL-6 levels as compared to the IR group (all P < 0.05). QJJ ameliorated the altered PI3K, GLUT4, and RAGE expression observed with IR. In conclusion, QJJ can improve IR in HepG2 cells, which may be mediated through the IRS-1/PI3K/GLUT4 signaling pathway as well as regulation of NF-κB-mediated inflammation and oxidative stress.

10.
Zhen Ci Yan Jiu ; 38(4): 297-300, 2013 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-24261300

RESUMO

OBJECTIVE: To observe the influence of different acupuncture manipulations at Zusanli (ST 36) on blood perfusion of skin microcirculation in healthy volunteer subjects. METHODS: A total of 10 healthy volunteers were recruited in the present study. Acupuncture manipulations of lifting-thrusting reinforcing and reducing, uniform reinforcing-reducing, and simple needle insertion were applied to right Zusanli (ST 36) for 2 min. Changes of blood perfusion in the right Zusanli (ST 36) area were detected 1 min, 5 min, 10 min, 15 min, 20 min, 25 min and 30 min after acupuncture stimulation, respectively by using a Pericam Perfusion Speckle Imager. The interval between two detections for different needling manipulations was 2 days at least. RESULTS: In comparison with pre-acupuncture stimulation, the blood perfusion levels of the skin microcirculation around the right Zusanli (ST 36) region were significantly increased from 1 min to 10 min following simple needle insertion, from 5 min to 30 min after uniform reinforcing-reducing manipulation, from 1 min to 30 min after reinforcing manipulation, and from 1 min to 25 min following reducing manipulation, respectively (P < 0.05, P < 0.01), and the effects of reinforcing manipulation were apparently superior to those of the reducing, uniform reinforcing-reducing manipulations and simple needle insertion in upregulating blood perfusion level (P < 0.05, P < 0.01). CONCLUSION: Lifting-thrusting reinforcing, reducing, uniform reinforcing-reducing manipulations of acupuncture needle, and simple needle insertion at Zusanli (ST 36) can obviously increase blood perfusion level in normal volunteer subjects, and the effect of reinforcing manipulation is apparently better.


Assuntos
Pontos de Acupuntura , Microcirculação , Pele/irrigação sanguínea , Terapia por Acupuntura , Adulto , Feminino , Voluntários Saudáveis , Humanos , Masculino , Adulto Jovem
11.
Zhongguo Zhen Jiu ; 31(12): 1097-100, 2011 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-22256646

RESUMO

OBJECTIVE: To establish the digitized visible human with Jiuwei (CV 15) involved. METHODS: With the virtual Chinese human (VCH) datasets and three-dimensional modeling software adopted, the knowledge on acupuncture and moxibustion as well as acupoint anatomy combined and the computer image processing software applied, the visualized browser software of Jiuwei (CV 15) was established. RESULTS: By establishing the interactive three-dimensional visualization browser software of acupoints, the location of Jiuwei (CV 15) was enabled to be expressed directly from all the levels, as well as the main adjacent tissue structure. It was suggested that Jiuwei (CV 15) should be punctured obliquely downward to avoid injuring the vital organs such as the heart and liver, and the safe depth of insertion should be 1.0-1.5 cm. CONCLUSION: The technology of digital visible human enables the three-dimensional expression of acupoint, which can be the platform of the digital teaching pattern. The research on the angle and depth of needling insertion at acupoint can be conducted in combination with teaching materials.


Assuntos
Pontos de Acupuntura , Terapia por Acupuntura/instrumentação , Terapia Assistida por Computador/instrumentação , Interface Usuário-Computador , Corpo Humano , Humanos , Imageamento Tridimensional , Software
12.
Water Sci Technol ; 62(10): 2277-85, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-21076213

RESUMO

Pollution from nonpoint-source (NPS) nitrogen (N) and phosphorus (P) are the main causes of eutrophication in lotic, lentic and coastal systems. The climate of cold regions might play an important role in disturbing environmental behavior of NPS N and P, influencing simulation of watershed scale hydrologic and nonpoint-source pollution models. The losses of NPS N and P increase in regions of cold climate. In cold seasons, accumulations of N and P are accelerated in soil with increasing fine root and aboveground biomass mortality, decreasing plant nutrient uptake, as well as freezing soil. N and P transformation is disturbed by soil frost and snow. Moreover, factors such as physical disruption of soil aggregates, pollutant accumulation in snowpack, and snow melting can all increase the NPS N and P losses to the waterbody. Therefore, NPS N and P in first flush are more serious in cold climate. All these effects, especially frozen soil and snowpack, make great challenges to watershed scale hydrologic and nonpoint-source pollution models simulation in cold climate. Model improvements of snowmelt runoff, nutrient losses in frozen soil, as well as N and P behavior have been initiated and will be continued to evaluate in terms of their performances and suitability with different scale, hydrologic and geologic conditions in the future.


Assuntos
Clima Frio , Nitrogênio/química , Fósforo/química , Poluentes Químicos da Água/química , Água/química , Modelos Teóricos
13.
Biochem J ; 397(3): 501-8, 2006 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-16686603

RESUMO

Bacterial phosphotriesterases are binuclear metalloproteins for which the catalytic mechanism has been studied with a variety of techniques, principally using active sites reconstituted in vitro from apoenzymes. Here, atomic absorption spectroscopy and anomalous X-ray scattering have been used to determine the identity of the metals incorporated into the active site in vivo. We have recombinantly expressed the phosphotriesterase from Agrobacterium radiobacter (OpdA) in Escherichia coli grown in medium supplemented with 1 mM CoCl2 and in unsupplemented medium. Anomalous scattering data, collected from a single crystal at the Fe-K, Co-K and Zn-K edges, indicate that iron and cobalt are the primary constituents of the two metal-binding sites in the catalytic centre (alpha and beta) in the protein expressed in E. coli grown in supplemented medium. Comparison with OpdA expressed in unsupplemented medium demonstrates that the cobalt present in the supplemented medium replaced zinc at the beta-position of the active site, which results in an increase in the catalytic efficiency of the enzyme. These results suggest an essential role for iron in the catalytic mechanism of bacterial phosphotriesterases, and that these phosphotriesterases are natively heterobinuclear iron-zinc enzymes.


Assuntos
Proteínas de Bactérias/química , Ferro/química , Hidrolases de Triester Fosfórico/química , Rhizobium/enzimologia , Sítios de Ligação , Catálise , Cobalto/química , Cristalização , Escherichia coli/enzimologia , Escherichia coli/genética , Proteínas Recombinantes/química , Espectrofotometria Atômica , Difração de Raios X , Zinco/química
14.
Shanghai Kou Qiang Yi Xue ; 15(2): 117-20, 2006 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-16685346

RESUMO

PURPOSE: To evaluate the role of surgical operating microscope and ultrasonic instruments in endodontic treatment of patients who underwent previous resinifying therapy. METHODS: 63 premolars and molars that had been treated with resinifying therapy before were selected for root canal therapy. The coronal portion of resinified root canals were negotiated with ultrasonic instruments under surgical operating microscope, and the apical portion was managed with small size hand files and 15% EDTA. The root canals of all cases were shaped by Nickel-Titanium rotary instruments Hero 642, and obturated with lateral condensation technique. The negotiation of root canal system, instrument fracture, alterations of canal morphology, and operation time were recorded. The efficiency of preparation and obturation was analyzed by radiographs before and after treatment. RESULTS: The root canals of 54 teeth were negotiated, enlarged and obturated, with a success rate of 85.7%. No complications were found, such as vertical fracture, ledge, perforation and instrument separation. Good result of treatment was achieved in the 54 cases. CONCLUSIONS: The use of surgical operating microscope and ultrasonic instruments is proved to be effective in negotiation of coronal portion of the resinified root canals. Nevertheless, the use of ultrasonic instruments in apical or curved portion of root canals is not encouraged.


Assuntos
Preparo de Canal Radicular/instrumentação , Tratamento do Canal Radicular/métodos , Procedimentos Cirúrgicos Ultrassônicos/métodos , Terapia por Ultrassom , Idoso , Dente Pré-Molar , Humanos , Microscopia , Dente Molar , Níquel , Titânio , Resultado do Tratamento , Procedimentos Cirúrgicos Ultrassônicos/instrumentação , Ultrassom
15.
Food Chem Toxicol ; 44(7): 1131-7, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16510229

RESUMO

In order to determine the fluoride content of various products of black tea and to make safety evaluations, 37 commodities in the different manufactured forms of tea were assessed by means of ion-selective electrode and spectrophotometric methods. The results showed wide differences in fluoride levels. The fluoride content was found 0.95-1.41 mg/L in black tea sticks, 0.70-2.44 mg/L in black tea granules and 1.15-6.01 mg/L in black tea bags. Of the products tested, the fluoride content was greatest in black tea bags, presumably because black tea bags are made of low cost, and older tea leaves. According to WHO's recommendation, fluoride exposure threshold for children is 2mg of daily intake and for adult, 4 mg. Assuming that children's daily intake of black tea was 800 ml and adult's 1500 ml, 56% of black tea bags should be considered unsafe for children and 44% should be considered unsafe for adults. At average rates of consumption, 24% of the black tea bags could result in an increasing risk of osteofluorosis and fractures (WHO). In the areas with drinking water fluoridation or other fluoride supplements, excessive fluoride exposure can become even more severe with even lower intake tea made from black tea bags. The potential hazards of fluoride arising from consumption of black tea has not aroused due public attention. Therefore, it is necessary to establish reliable fluoride surveillance in food and beverage commodities and conduct additional epidemiological research on fluoride hazards. In addition, it is urgent that governmental and international agencies adopt safe standards of fluoride content in tea commodities.


Assuntos
Fluoretos/análise , Chá/química , Eletroquímica , Eletrodos , Fluoretos/efeitos adversos , Controle de Qualidade , Padrões de Referência
16.
Appl Environ Microbiol ; 70(1): 404-12, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14711669

RESUMO

Phosphotriesterases catalyze the hydrolytic detoxification of phosphotriester pesticides and chemical warfare nerve agents with various efficiencies. The directed evolution of phosphotriesterases to enhance the breakdown of poor substrates is desirable for the purposes of bioremediation. A limiting factor in the identification of phosphotriesterase mutants with increased activity is the ability to effectively screen large mutant libraries. To this end, we have investigated the possibility of coupling phosphotriesterase activity to cell growth by using methyl paraoxon as the sole phosphorus source. The catabolism of paraoxon to phosphate would occur via the stepwise enzymatic hydrolysis of paraoxon to dimethyl phosphate, methyl phosphate, and then phosphate. The Escherichia coli strain DH10B expressing the phosphotriesterase from Agrobacterium radiobacter P230 (OpdA) is unable to grow when paraoxon is used as the sole phosphorus source. Enterobacter aerogenes is an organism capable of growing when dimethyl phosphate is the sole phosphorus source. The enzyme responsible for hydrolyzing dimethyl phosphate has been previously characterized as a nonspecific phosphohydrolase. We isolated and characterized the genes encoding the phosphohydrolase operon. The operon was identified from a shotgun clone that enabled E. coli to grow when dimethyl phosphate is the sole phosphorus source. E. coli coexpressing the phosphohydrolase and OpdA grew when paraoxon was the sole phosphorus source. By constructing a short degradative pathway, we have enabled E. coli to use phosphotriesters as a sole source of phosphorus.


Assuntos
Escherichia coli/crescimento & desenvolvimento , Inseticidas/metabolismo , Paraoxon/metabolismo , Diester Fosfórico Hidrolases/metabolismo , Hidrolases de Triester Fosfórico/metabolismo , Fósforo/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , Meios de Cultura , Enterobacter aerogenes/enzimologia , Enterobacter aerogenes/genética , Escherichia coli/enzimologia , Escherichia coli/genética , Dados de Sequência Molecular , Óperon , Compostos Organofosforados/metabolismo , Diester Fosfórico Hidrolases/genética , Hidrolases de Triester Fosfórico/genética
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