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Tandem
Terms modified by Tandem Selected AbstractsRetracted: Determination of scutellarin isomer, a predominant metabolite of scutellarin, in human plasma by HPLC/tandem mass spectrometry and its application to a pharmacokinetic study in Chinese healthy volunteersBIOMEDICAL CHROMATOGRAPHY, Issue 8 2007Chun-hua Xia Retraction: The following article from Biomedical Chromatography, "Determination of scutellarin isomer, a predominant metabolite of scutellarin, in human plasma by HPLC/tandem mass spectrometry and its application to the pharmacokinetic study in Chinese healthy volunteers" by Chun-hua Xia, Yu-qing Xiong, and Guang-ji Wang, published online on 21 June 2007 in Wiley Interscience (www.interscience.wiley.com/journal/bmc), has been retracted at the authors' request. [source] A Tandem, Nitroalkene Conjugate Addition/[3+2] Cycloaddition Approach to the Synthesis of the Pentacyclic Core of (±)-ScandineADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 16-17 2006Scott Abstract The complete pentacyclic core of the melodinus alkaloid scandine has been synthesized. The synthetic strategy features two key steps: (1) a tandem nitroalkene conjugate addition/[3+2] cycloaddition of the resulting silyl nitronate and (2) an intramolecular Heck reaction of an aryl iodide with a ,-disubstituted allylic alcohol which set a highly congested, quaternary stereogenic center with the concomitant formation of an aldehyde. Intramolecular reductive amination with this aldehyde completed the pentacyclic core. [source] MRI Assessment Followed by Successful Mechanical Recanalization of a Complete Tandem (Internal Carotid/Middle Cerebral Artery) Occlusion and Reversal of a 10-Hour Fixed DeficitJOURNAL OF NEUROIMAGING, Issue 1 2008Catalina C. Ionita MD ABSTRACT BACKGROUND Mechanical clot extraction up to 8 hours after stroke onset is an alternative strategy for opening large vessels, especially for patients ineligible for intravenous thrombolysis. Safety beyond this therapeutic window is untested. METHODS An 81-year-old woman presented 8 hours after she developed left-sided weakness and dysarthria with a National Institutes of Health Stroke Scale (NIHSS) score fluctuating between 6 and 13. Neuroimaging revealed a large perfusion deficit with no diffusion abnormalities. An emergent cerebral angiogram revealed a complete internal carotid artery terminus occlusion. RESULTS Successful mechanical thrombectomy was performed without complication and resulted in almost complete reversal of the patient's deficit to an NIHSS score of 1, 10 hours after stroke onset. CONCLUSION Patients with large hypoperfused areas and minimal diffusion abnormalities on the MRI may benefit from mechanical thrombectomy beyond an 8-hour window. [source] Thin-film silicon solar cell technologyPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 2-3 2004A. V. Shah Abstract This paper describes the use, within p,i,n - and n,i,p -type solar cells, of hydrogenated amorphous silicon (a-Si:H) and hydrogenated microcrystalline silicon (,c-Si:H) thin films (layers), both deposited at low temperatures (200°C) by plasma-assisted chemical vapour deposition (PECVD), from a mixture of silane and hydrogen. Optical and electrical properties of the i -layers are described. These properties are linked to the microstructure and hence to the i -layer deposition rate, that in turn, affects throughput in production. The importance of contact and reflection layers in achieving low electrical and optical losses is explained, particularly for the superstrate case. Especially the required properties for the transparent conductive oxide (TCO) need to be well balanced in order to provide, at the same time, for high electrical conductivity (preferably by high electron mobility), low optical absorption and surface texture (for low optical losses and pronounced light trapping). Single-junction amorphous and microcrystalline p,i,n -type solar cells, as fabricated so far, are compared in their key parameters (Jsc, FF, Voc) with the [theoretical] limiting values. Tandem and multijunction cells are introduced; the ,c-Si: H/a-Si: H or [micromorph] tandem solar cell concept is explained in detail, and recent results obtained here are listed and commented. Factors governing the mass-production of thin-film silicon modules are determined both by inherent technical reasons, described in detail, and by economic considerations. The cumulative effect of these factors results in distinct efficiency reductions from values of record laboratory cells to statistical averages of production modules. Finally, applications of thin-film silicon PV modules, especially in building-integrated PV (BIPV) are shown. In this context, the energy yields of thin-film silicon modules emerge as a valuable gauge for module performance, and compare very favourably with those of other PV technologies. Copyright © 2004 John Wiley & Sons, Ltd. [source] Hydrodeoxygenation of Lignin-Derived Phenols into Alkanes by Using Nanoparticle Catalysts Combined with Brønsted Acidic Ionic Liquids,ANGEWANDTE CHEMIE, Issue 32 2010Ning Yan Dr. Wertschöpfung im Tandem: Ein katalytisches System bestehend aus Metall-Nanopartikeln (NPs) und einer funktionalisierten Brønsted-sauren ionischen Flüssigkeit (IL) in einer nichtfunktionalisierten IL wird beschrieben (siehe Bild). Das System ist hoch effizient für die Umsetzung von Lignin abgeleiteter phenolischer Verbindungen zu Alkanen, wobei die Hydrierung und Dehydratisierung als Tandemprozess ablaufen. [source] ChemInform Abstract: Tandem ,-Alkylation,,-Arylation of Amines by Carbolithiation and Rearrangement of N-Carbamoyl Enamines (Vinyl Ureas).CHEMINFORM, Issue 38 2010Jonathan Clayden Abstract Organolithiums add in an umpolung fashion to the ,-carbon of N-carbamoyl enamines. [source] ChemInform Abstract: Stereoselective Tandem [4 + 2]/[3 + 2] Cycloaddition Reactions of 3,3,3-Trichloro(trifluoro)-1-nitropropenes and 2,3-Dihydrofuran.CHEMINFORM, Issue 25 2010Vladislav Yu. Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Tandem ,-Enamino Ester Formation and Cyclization with o-Alkynyl Anilines Catalyzed by InBr3: Efficient Synthesis of ,-(N-Indolyl)-,,,-unsaturated Esters.CHEMINFORM, Issue 24 2009Kenichi Murai Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Sc(OTf)3 -Catalyzed Smooth Tandem [3 + 2] Cycloaddition/Ring Opening of Donor,Acceptor Cyclopropane 1,1-Diesters with Enol Silyl Ethers.CHEMINFORM, Issue 9 2009Jie Fang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Zinc Oxide,Tetrabutylammonium Bromide Tandem as a Highly Efficient, Green, and Reusable Catalyst for the Michael Addition of Pyrimidine and Purine Nucleobases to ,,,-Unsaturated Esters under Solvent-Free Conditions.CHEMINFORM, Issue 39 2008Abdolkarim Zare Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Phosphine-Catalyzed Tandem ,-O-Addition and Transesterification of Oxygen Pronucleophiles on Arylpropiolates: A New Route to Dioxygenated Heterocycles.CHEMINFORM, Issue 25 2007Sandra Gabillet Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] An Efficient Route to Thieno[2,3-d]pyrimidine Derivatives by Tandem [2,3] and [3,3] Sigmatropic Rearrangement.CHEMINFORM, Issue 15 2007Krishna C. Majumdar Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] One-Pot Tandem 1,4,1,2-Addition of Phosphites to ,,,-Unsaturated Imines for the Synthesis of Glutamic Acid Analogues.CHEMINFORM, Issue 12 2006Kristof Moonen Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Synthesis of Postulated Molecular Probes: Stereoselective Free-Radical-Mediated C-Glycosylation in Tandem with Hydrogen Transfer.CHEMINFORM, Issue 24 2005Yvan Guindon Abstract For Abstract see ChemInform Abstract in Full Text. [source] Ruthenium-Catalyzed Cyclization of 3-En-1-ynyl Imines with Nucleophiles via Tandem 5-exo-dig Cyclization and Nucleophilic Addition.CHEMINFORM, Issue 13 2005Hung-Chin Shen Abstract For Abstract see ChemInform Abstract in Full Text. [source] Stereoselective Tandem 1,4-Addition Reactions for Benzenes: A Comparison of Os(II), Re(I), and W(0) Systems.CHEMINFORM, Issue 11 2005Fei Ding Abstract For Abstract see ChemInform Abstract in Full Text. [source] Highly Substituted Enynes via a Palladium-Catalyzed Tandem Three Carbon,Carbon Bonds Forming Reaction Procedure from Benzyl Halides and Alkynyl Tributyltin Reagents.CHEMINFORM, Issue 35 2004Laurent Romain Pottier Abstract For Abstract see ChemInform Abstract in Full Text. [source] Convenient, Tandem and One-Reaction Vessel Synthesis of Mixed Dialkylated 2-Naphthols from 2-TetraloneCHEMINFORM, Issue 40 2003Amitabh Jha Abstract For Abstract see ChemInform Abstract in Full Text. [source] Identification of metabolites of adonifoline, a hepatotoxic pyrrolizidine alkaloid, by liquid chromatography/tandem and high-resolution mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 24 2009Aizhen Xiong Hepatotoxic pyrrolizidine alkaloid (HPA)-containing plants have always been a threat to human and livestock health worldwide. Adonifoline, a main HPA in Senecio scandens Buch.-Ham. ex D. Don (Qianli guang), was used officially as an infusion in cases of oral and pharyngeal infections in China. In this study in vivo metabolism of adonifoline was studied for the first time by identifying the metabolites of adonifoline present in bile, urine and feces of rats using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MSn) (ion trap) as well as liquid chromatography/electrospray ionization high-resolution mass spectrometry (LC/ESI-HRMS) (quadrupole-time of flight). In total 19 metabolites were identified and, among them, retronecine- N -oxides were confirmed by matching their fragmentation patterns with their fully characterized synthetic compounds. These metabolites are all involved in both phase I and phase II metabolic processes and the principal in vivo metabolism pathways of adonifoline were proposed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Irritants in combination with a synergistic or additive effect on the skin response: an overview of tandem irritation studiesCONTACT DERMATITIS, Issue 6 2006Francisca Kartono Sodium lauryl sulfate (SLS) has often been chosen as a model for irritant contact dermatitis (ICD) to study the effect of irritants in combination (1,14). Recently ,tandem', or sequential, exposures with SLS have been performed to study the mechanism of skin barrier impairment in ICD (1,6, 15). The assessment of reactions have been documented with visual scoring, transepidermal water loss (TEWL), skin colour reflectance measurements, skin blood flow; among which TEWL has been noted as the most sensitive value (16). The matched control groups were treated with either a single exposure to a single irritant or in tandem with the same irritant repeatedly. Synergistic and additive effects have been reported for various tandem pairs of irritants, however, the mechanism for both remains unclear. The results of tandem irritation studies were evaluated to define and investigate the responses produced and deduce a possible mechanism of action. Clinical ramifications, albeit complex, are discussed. [source] A Delphi survey of the views of adult male patients with personality disorders on psychoeducation and social problem-solving therapyCRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 5 2007Mary McMurran Background,Psychoeducation and social problem-solving therapy are treatment components that work well in tandem for offenders with personality disorders, hence it is worthwhile to maintain and improve their effectiveness. Aim,The aim was to seek patients' views of these therapies to contribute to their development. Method,A Delphi survey was conducted with all 12 male inpatients of a personality disorder hospital treatment unit. Results,Round 1 produced 30 statements for psychoeducation and 59 for social problem-solving therapy to be rated in Round 2. There was consensus at a level of 70% for all items. Both psychoeducation and social problem-solving therapies were viewed as useful by these patients. The men also suggested improvements in psychoeducation, including minimizing the delay between assessment and feedback, provision of reference material, preparation for the work and support afterwards. Areas identified for improvement in social problem-solving therapy included more frequent review of progress, greater consistency of delivery, eliciting problems more effectively, providing reference material, supporting patients in group work, and the development of an advanced therapy. Discussion,A Delphi approach to evaluation of therapies with the people receiving them is not only feasible but seems to offer a practical way of making useful clinical adjustments to the work. Further research with larger samples might usefully focus on whether such an approach enhances treatment compliance. Copyright © 2007 John Wiley & Sons, Ltd. [source] AN ASSESSMENT OF RECENT TRENDS IN GIRLS' VIOLENCE USING DIVERSE LONGITUDINAL SOURCES: IS THE GENDER GAP CLOSING?CRIMINOLOGY, Issue 2 2005DARRELL STEFFENSMEIER Applying Dickey-Fuller time series techniques in tandem with intuitive plot-displays, we examine recent trends in girls' violence and the gender gap as reported in four major sources of longitudinal data on youth violence. These sources are arrest statistics of the Uniform Crime Reports, victimization data of the National Crime Victimization Survey (where the victim identifies sex of offender) and self-reported violent behavior of Monitoring the Future and National Youth Risk Behavior Survey. We find that the rise in girls' violence over the past one to two decades as counted in police arrest data from the Uniform Crime Reports is not borne out in unofficial longitudinal sources. Several net-widening policy shifts have apparently escalated girls' arrest-proneness: first, stretching definitions of violence to include more minor incidents that girls in relative terms are more likely to commit; second, increased policing of violence between intimates and in private settings (for example, home, school) where girls' violence is more widespread; and, third, less tolerant family and societal attitudes toward juvenile females. These developments reflect both a growing intolerance of violence in the law and among the citizenry and an expanded application of preventive punishment and risk management strategies that emphasize early identification and enhanced formal control of problem individuals or groups, particularly problem youth. [source] Near-infrared dyes for six-color immunophenotyping by laser scanning cytometryCYTOMETRY, Issue 3 2002Andreas O.H. Gerstner Abstract Background To adequately analyze the complexity of the immune system and reduce the required sample volume for immunophenotyping in general, more measurable colors for the discrimination of leukocyte subsets are necessary. Immunophenotyping by the laser scanning cytometer (LSC), a slide-based cytometric technology, combines cell detection based on multiple colors with their subsequent visualization without the need for physical cell sorting. In the present study, the filter setting of the LSC was adapted for the measurement of the far-red emitting dye cyanine 7 (Cy7), thereby increasing the number of measurable commercially available fluorochromes. Methods The optical filters of the LSC were replaced,photomultiplier (PMT) 3/allophycocyanin (APC): 740-nm dichroic long pass, and 670-/55-nm bandpass; PMT 4/Cy7: 810-/90-nm bandpass. Peripheral blood leukocytes were stained directly by fluorochrome-labeled antibodies or by indirect staining. The tandem dyes of Cy7 (phycoerythrin [PE]-Cy7, APC-Cy7) and the fluorochromes fluorescein isothiocyanate (FITC), PE, PE-Cy5, and APC were tested alone and in different combinations. Results With the new filter combination and tandem fluorochromes, Cy7 was measurable at 488-nm (argon laser) or 633-nm (helium-neon laser) excitation. Resolution was in the range of FITC for PE-Cy7 but approximately 30% lower for APC-Cy7; spillover into the respective donor fluorochrome channel for both tandem dyes was prominent. A six-color panel for leukocyte subtyping was designed. Conclusions With this adaptation, it is possible to measure the tandem conjugates PE-Cy7 and APC-Cy7. This new setup opens the way for six-color immunophenotyping by LSC. Cytometry 48:115,123, 2002. © 2002 Wiley-Liss, Inc. [source] How adhesion, migration, and cytoplasmic calcium transients influence interleukin-1, mRNA stabilization in human monocytesCYTOSKELETON, Issue 3 2004P. Pomorski Abstract We investigated the mechanisms by which primary human monocyte migration and the production of important cytokines are co-regulated. Motile monocytes underwent cyclic morphologic and adhesive changes that were associated with intracellular free calcium changes; in such cells, cytokine transcripts were unstable and translationally repressed. Agents that activate monocytes, including lipopolysacharrides (LPS), cytomegalovirus (CMV), and tumor necrosis factor (TNF,), have been shown to de-repress translation and these agents stabilize adhesion-induced transcripts for IL-l, and IL-8 and markedly diminish cell migration in the presence of autologous serum. LPS suppressed Rho A activity and either this agent or C3 transferase elevated intracellular free calcium, stabilized transcripts, and, in tandem, inhibited cell migration by preventing tail retraction, a prerequisite for cell translocation. These results, therefore, suggest that monocyte activating agents inhibit the RhoA pathway and continuously elevate intracellular calcium leading to a concomitant decrease in monocyte migration and stabilization of cytokine transcripts prior to translation. Cell Motil. Cytoskeleton 57:143,157, 2004. © 2004 Wiley-Liss, Inc. [source] Developmental profiles for multiple object tracking and spatial memory: typically developing preschoolers and people with Williams syndromeDEVELOPMENTAL SCIENCE, Issue 3 2010Kirsten O'Hearn The ability to track moving objects, a crucial skill for mature performance on everyday spatial tasks, has been hypothesized to require a specialized mechanism that may be available in infancy (i.e. indexes). Consistent with the idea of specialization, our previous work showed that object tracking was more impaired than a matched spatial memory task in individuals with Williams syndrome (WS), a genetic disorder characterized by severe visuo-spatial impairment. We now ask whether this unusual pattern of performance is a reflection of general immaturity or of true abnormality, possibly reflecting the atypical brain development in WS. To examine these two possibilities, we tested typically developing 3- and 4-year-olds and people with WS on multiple object tracking (MOT) and memory for static spatial location. The maximum number of objects that could be correctly tracked or remembered (estimated from the k -statistic) showed similar developmental profiles in typically developing 3- and 4-year-old children, but the WS profile differed from either age group. People with WS could track more objects than 3-year-olds, and the same number as 4-year-olds, but they could remember the locations of more static objects than both 3- and 4-year-olds. Combining these data with those from our previous studies, we found that typically developing children show increases in the number of objects they can track or remember between the ages of 3 and 6, and these increases grow in parallel across the two tasks. In contrast, object tracking in older children and adults with WS remains at the level of 4-year-olds, whereas the ability to remember multiple locations of static objects develops further. As a whole, the evidence suggests that MOT and memory for static location develop in tandem typically, but not in WS. Atypical development of the parietal lobe in people with WS could play a causal role in the abnormal, uneven pattern of performance in WS. This interpretation is consistent with the idea that multiple object tracking engages different mechanisms from those involved in memory for static object location, and that the former can be particularly disrupted by atypical development. [source] Moving Beyond Postdevelopment: Facilitating Indigenous Alternatives for "Development"ECONOMIC GEOGRAPHY, Issue 4 2003George N. Curry Using the example of smallholder oil-palm production in Papua New Guinea, this article illustrates how elements of a market economy and modernity become enmeshed and partly transformed by local place-based nonmarket practices. The persistence, even efflorescence, of indigenous gift exchange, in tandem with greater participation in the market economy, challenges conventional notions about the structures and meanings of development. The introduced market economy can be inflected to serve indigenous sociocultural and economic goals by place-based processes that transform market relations and practices into nonmarket social relationships. These kinds of inflections of the market economy are common and widespread and therefore worthy of consideration for their theoretical insights into processes of social and economic change and the meanings of development. The article concludes by outlining some preliminary thoughts on how development practice could be modified to provide more scope for this process of inflection, so that development strategies accord better with indigenous sociocultural meanings of development. [source] TWIN SONS OF DIFFERENT MOTHERS: THE LONG AND THE SHORT OF THE TWIN DEFICITS DEBATEECONOMIC INQUIRY, Issue 4 2009KEVIN GRIER Interest in the twin deficits hypothesis fluctuates in tandem with the U.S. current account deficit. Surprisingly though, a statistically robust relationship between budget and trade deficits has been difficult to pin down. We argue that a big part of this difficulty is due to the failure to allow for structural breaks in the series when (either explicitly or implicitly) modeling their time series properties. We show that both series are break stationary (and conditionally heteroskedastic) and argue that while there is no common pattern in the long run, the short-run dynamics reveal a sizeable and fairly persistent positive relationship between budget deficit shocks and current account deficit shocks. (JEL F41, E6, H6) [source] Can Growth Ease Class Conflict?ECONOMICS & POLITICS, Issue 1 2002E. Somanathan This paper proposes a theory that links labor supply to wage growth and economic growth, and the conflict of interest between capital and labor. During the early stages of industrialization of a country, "surplus" labor drawn from the traditional sector of the economy is available to the modern capitalist sector at a constant or only slowly rising wage. As industrialization proceeds, this labor surplus vanishes, leading to wages rising in tandem with the growth of output. As long as there is surplus labor, workers in the modern capitalist sector, who are organized, have little interest in growth as it does not raise wages. The effect of growth is external to them, simply drawing more workers into the capitalist sector and enabling the entrants to receive rents. So capitalist-sector workers would like to redistribute income regardless of the adverse effect on growth. Once the economy grows enough for the subsistence sector to vanish, further growth raises wages. Hence, this change in the structure of the economy leads to a reduction in the intensity of the labor,capital conflict. The dual economy model implies that growth rates rise over time and fall after the exhaustion of the labor surplus which is consistent with the stylized fact of economic growth. [source] Improved workup for glycosaminoglycan disaccharide analysis using CE with LIF detectionELECTROPHORESIS, Issue 22 2008Alicia M. Hitchcock Abstract This work describes improved workup and instrumental conditions to enable robust, sensitive glycosaminoglycan (GAG) disaccharide analysis from complex biological samples. In the process of applying CE with LIF to GAG disaccharide analysis in biological samples, we have made improvements to existing methods. These include (i) optimization of reductive amination conditions, (ii) improvement in sensitivity through the use of a cellulose cleanup procedure for the derivatization, and (iii) optimization of separation conditions for robustness and reproducibility. The improved method enables analysis of disaccharide quantities as low as 1,pmol prior to derivatization. Biological GAG samples were exhaustively digested using lyase enzymes, the disaccharide products and standards were derivatized with the fluorophore 2-aminoacridone and subjected to reversed polarity CE-LIF detection. These conditions resolved all known chondroitin sulfate (CS) disaccharides or 11 of 12 standard heparin/heparan sulfate disaccharides, using 50,mM phosphate buffer, pH 3.5, and reversed polarity at 30,kV with 0.3,psi pressure. Relative standard deviation in migration times of CS ranged from 0.1 to 2.0% over 60 days, and the relative standard deviations of peak areas were less than 3.2%, suggesting that the method is reproducible and precise. The CS disaccharide compositions are similar to those obtained by our group using tandem MS. The reversed polarity CE-LIF disaccharide analysis protocol yields baseline resolution and quantification of heparin/heparan sulfate and CS/dermatan sulfate disaccharides from both standard preparations and biologically relevant proteoglycan samples. The improved CE-LIF method enables disaccharide quantification of biologically relevant proteoglycans from small samples of intact tissue. [source] Isolation and characterization of Tn -Dha1, a transposon containing the tetrachloroethene reductive dehalogenase of Desulfitobacterium hafniense strain TCE1ENVIRONMENTAL MICROBIOLOGY, Issue 1 2005Julien Maillard Summary A new 9.9 kb catabolic transposon, Tn -Dha1, containing the gene responsible for tetrachloroethene (PCE) reductive dechlorination activity, was isolated from Desulfitobacterium hafniense strain TCE1. Two fully identical copies of the insertion sequence ISDha1, a new member of the IS256 family, surround the gene cluster pceABCT, a truncated gene for another transposase and a short open reading frame with homology to a member of the twin-arginine transport system (tatA). Evidence was obtained by Southern blot for an alternative form of the transposon element as a circular molecule containing only one copy of ISDha1. This latter structure most probably represents a dead-end product of the transposition of Tn -Dha1. Strong indications for the transposition activity of ISDha1 were given by polymerase chain reaction (PCR) amplification and sequencing of the intervening sequence located between both inverted repeats (IR) of ISDha1 (IR junction). A stable genomic ISDha1 tandem was excluded by quantitative real-time PCR. Promoter mapping of the pceA gene, encoding the reductive dehalogenase, revealed the presence of a strong promoter partially encoded in the right inverted repeat of ISDha1. A sequence comparison with pce gene clusters from Desulfitobacterium sp. strains PCE-S and Y51 and from Dehalobacter restrictus, all of which show 100% identity for the pceAB genes, indicated that both Desulfitobacterium strains seem to possess the same transposon structure, whereas only the pceABCT gene cluster is conserved in D. restrictus. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||