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Sample records for affecting plasmid production

  1. Factors affecting plasmid production in Escherichia coli from a resource allocation standpoint

    Directory of Open Access Journals (Sweden)

    Cunningham Drew S

    2009-05-01

    Full Text Available Abstract Background Plasmids are being reconsidered as viable vector alternatives to viruses for gene therapies and vaccines because they are safer, non-toxic, and simpler to produce. Accordingly, there has been renewed interest in the production of plasmid DNA itself as the therapeutic end-product of a bioprocess. Improvement to the best current yields and productivities of such emerging processes would help ensure economic feasibility on the industrial scale. Our goal, therefore, was to develop a stoichiometric model of Escherichia coli metabolism in order to (1 determine its maximum theoretical plasmid-producing capacity, and to (2 identify factors that significantly impact plasmid production. Results Such a model was developed for the production of a high copy plasmid under conditions of batch aerobic growth on glucose minimal medium. The objective of the model was to maximize plasmid production. By employing certain constraints and examining the resulting flux distributions, several factors were determined that significantly impact plasmid yield. Acetate production and constitutive expression of the plasmid's antibiotic resistance marker exert negative effects, while low pyruvate kinase (Pyk flux and the generation of NADPH by transhydrogenase activity offer positive effects. The highest theoretical yield (592 mg/g resulted under conditions of no marker or acetate production, nil Pyk flux, and the maximum allowable transhydrogenase activity. For comparison, when these four fluxes were constrained to wild-type values, yields on the order of tens of mg/g resulted, which are on par with the best experimental yields reported to date. Conclusion These results suggest that specific plasmid yields can theoretically reach 12 times their current experimental maximum (51 mg/g. Moreover, they imply that abolishing Pyk activity and/or transhydrogenase up-regulation would be useful strategies to implement when designing host strains for plasmid

  2. Role of Plasmid in Production of Acetobacter Xylinum Biofilms

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    Abbas Rezaee

    2005-01-01

    Full Text Available Acetobacter xylinum has the ability to produce cellulotic biofilms. Bacterial cellulose is expected to be used in many industrial or biomedical materials for its unique characteristics. A. xylinum contains a complex system of plasmid DNA molecules. A 44 kilobases (kb plasmid was isolated in wild type of A. xylinum. To improve the cellulose producing ability of A. xylinum, role of the plasmid in production of cellulose was studied. The comparisons between wild type and cured cells of A. xylinum showed that there is considerably difference in cellulose production. In order to study the relationship between plasmid and the rate of cellulose production, bacteria were screened for plasmid profile by a modified method for preparation of plasmid. This method yields high levels of pure plasmid DNA that can be used for common molecular techniques, such as digestion and transformation, with high efficiency.

  3. Production and pharmaceutical formulation of plasmid DNA vaccines

    NARCIS (Netherlands)

    van der Heijden, I.

    2013-01-01

    Research leading to the thesis ‘Production and pharmaceutical formulation of plasmid DNA vaccines‘ can be divided into two parts. The first part describes the development of a Good Manufacturing Practice (GMP) compliant plasmid DNA production process of pDNA vaccines for the treatment of Human papil

  4. Inducible Escherichia coli fermentation for increased plasmid DNA production.

    Science.gov (United States)

    Carnes, Aaron E; Hodgson, Clague P; Williams, James A

    2006-11-01

    Bacterial plasmids are the vectors of choice for DNA vaccines and short-term gene therapeutics. Growing plasmid DNA by microbial (Escherichia coli) fermentation is usually combined with alkaline lysis/chromatography methods of purification. To date, typical plasmid fermentation media and processes result in yields of 100-250 mg of plasmid DNA/l of culture medium, using standard high-copy pUC origin-containing plasmids. In order to address this initial and yield-limiting upstream step, we identified novel fermentation control parameters for fed-batch fermentation. The resulting fermentation strategies significantly increased specific plasmid yield with respect to cell mass while enhancing plasmid integrity and maintaining supercoiled DNA content. Fed-batch fermentation yield exceeding 1000 mg of plasmid DNA/l was obtained after reduction of plasmid-mediated metabolic burden during growth, and yields up to 1500 mg of plasmid DNA/l have been achieved with optimized plasmid backbones. Interestingly, by inducing high plasmid levels after sufficient biomass accumulation at low temperature and restricted growth, cells were able to tolerate significantly higher plasmid quantities than cells grown by conventional processes. This 5-10-fold increase in plasmid yield dramatically decreases plasmid manufacturing costs and improves the effectiveness of downstream purification by reducing the fraction of impurities. PMID:16819941

  5. Resveratrol production in bioreactor: Assessment of cell physiological states and plasmid segregational stability

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    Margarida S. Afonso

    2015-03-01

    Full Text Available Resveratrol is a plant secondary metabolite commonly found in peanuts and grapevines with significant health benefits. Recombinant organisms can produce large amounts of resveratrol and, in this work, Escherichia coli BW27784 was used to produce resveratrol in bioreactors while monitoring cell physiology and plasmid stability through flow cytometry and real-time qPCR, respectively. Initially, the influence of culture conditions and precursor addition was evaluated in screening assays and the data gathered was used to perform the bioreactor assays, allowing the production of 160 μg/mL of resveratrol. Cellular physiology and plasmid instability affected the final resveratrol production, with lower viability and plasmid copy numbers associated with lower yields. In sum, this study describes new tools to monitor the bioprocess, evaluating the effect of culture conditions, and its correlation with cell physiology and plasmid segregational stability, in order to define a viable and scalable bioprocess to fulfill the need for larger quantities of resveratrol.

  6. Effects of medium composition on the production of plasmid DNA vector potentially for human gene therapy

    Institute of Scientific and Technical Information of China (English)

    XU Zhi-nan; SHEN Wen-he; CHEN Hao; CEN Pei-lin

    2005-01-01

    Plasmid vector is increasingly applied to gene therapy or gene vaccine. The production of plasmid pCMV-AP3 for cancer gene therapy was conducted in a modified MBL medium using a recombinant E. coli BL21 system. The effects of different MMBL components on plasmid yield, cell mass and specific plasmid DNA productivity were evaluated on shake-flask scale. The results showed that glucose was the optimal carbon source. High plasmid yield (58.3 mg/L) was obtained when 5.0 g/L glucose was added to MMBL. Glycerol could be chosen as a complementary carbon source because of the highest specific plasmid productivity (37.9 mg DNA/g DCW). After tests of different levels of nitrogen source and inorganic phosphate, a modified MMBL medium was formulated for optimal plasmid production. Further study showed that the initial acetate addition (less than 4.0 g/L) in MMBL improved plasmid production significantly, although it inhibited cell growth. The results will be useful for large-scale plasmid production using recombinant E. coli system.

  7. Strategies of plasmid DNA production and their influence on therapeutic applications

    OpenAIRE

    Silva, Filomena Augusta Almeida e

    2011-01-01

    Current developments in gene therapy and DNA vaccination, plasmid DNA vectors are becoming increasingly appealing as therapeutics towards a large number of diseases such as cancer, infectious and cardiovascular diseases. This popularity is creating the demand for high quantities of highly purified plasmid DNA which in turn requires the design of high pDNA yield bioprocesses. However, opposed to recombinant protein production, research on pDNA production is still needed, in order to have...

  8. Large-scale production of endotoxin-free plasmids for transient expression in mammalian cell culture.

    Science.gov (United States)

    Rozkov, Aleksei; Larsson, Bert; Gillström, Stefan; Björnestedt, Robert; Schmidt, Stefan R

    2008-02-15

    Transient expression of recombinant proteins in mammalian cell culture in a 100-L scale requires a large quantity of plasmid that is very labour intensive to achieve with shake flask cultures and commercially available plasmid purification kits. In this paper we describe a process for plasmid production in 100-mg scale. The fermentation is carried out in a 4-L fed-batch culture with a minimal medium. The detection of the end of batch and triggering the exponential (0.1 h(-1)) feed profile was unattended and controlled by Multi-fermenter Control System. A restricted specific growth rate in fed-batch culture increased the specific plasmid yield compared to batch cultures with minimal and rich media. This together with high biomass concentration (68-107 g L(-1) wet weight) achieves high volumetric yields of plasmid (95-277 mg L(-1) depending on the construct). The purification process consisted of alkaline lysis, lysate clarification and ultrafiltration, two-phase extraction with Triton X-114 for endotoxin removal, anion-exchange chromatography as a polishing step, ultrafiltration and sterile filtration. Both fermentation and purification processes were used without optimisation for production of four plasmids yielding from 39 to 163 mg of plasmids with endotoxin content of 2.5 EU mg(-1) or less. PMID:17680665

  9. Plasmid Transfer of Plasminogen K1-5 Reduces Subcutaneous Hepatoma Growth by Affecting Inflammatory Factors

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    Lea A. Koch

    2014-01-01

    Full Text Available There is evidence that plasminogen K1-5 (PlgK1-5 directly affects tumour cells and inflammation. Therefore, we analysed if PlgK1-5 has immediate effects on hepatoma cells and inflammatory factors in vitro and in vivo. In vitro, effects of plasmid encoding PlgK1-5 (pK1-5 on Hepa129, Hepa1-6, and HuH7 cell viability, apoptosis, and proliferation as well as VEGF and TNF-alpha expression and STAT3-phosphorylation were investigated. In vivo, tumour growth, proliferation, vessel density, and effects on vascular endothelial growth factor (VEGF and tumour necrosis factor alpha (TNF-alpha expression were examined following treatment with pK1-5. In vivo, pK1-5 halved cell viability; cell death was increased by up to 15% compared to the corresponding controls. Proliferation was not affected. VEGF, TNF-alpha, and STAT3-phosphorylation were affected following treatment with pK1-5. In vivo, ten days after treatment initiation, pK1-5 reduced subcutaneous tumour growth by 32% and mitosis by up to 77% compared to the controls. Vessel density was reduced by 50%. TNF-alpha levels in tumour and liver tissue were increased, whereas VEGF levels in tumours and livers were reduced after pK1-5 treatment. Taken together, plasmid gene transfer of PlgK1-5 inhibits hepatoma (cell growth not only by reducing vessel density but also by inducing apoptosis, inhibiting proliferation, and triggering inflammation.

  10. ColE1-plasmid production in Escherichia coli: Mathematical Simulation and Experimental Validation

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    Inga eFreudenau

    2015-09-01

    Full Text Available Plasmids have become very important as pharmaceutical gene vectors in the fields of gene therapy and genetic vaccination in the last years. In this study, we present a dynamic model to simulate the ColE1-like plasmid replication control, once for a DH5α-strain carrying a low copy plasmid (DH5α-pSUP 201-3 and once for a DH5α-strain carrying a high copy plasmid (DH5α-pCMV-lacZ by using ordinary differential equations (ODE and the MATLAB software. The model includes the plasmid replication control by two regulatory RNA molecules (RNAI and RNAII as well as the replication control by uncharged tRNA molecules. To validate the model, experimental data like RNAI- and RNAII concentration, plasmid copy number (PCN, and growth rate for three different time points in the exponential phase were determined. Depending on the sampled time point, the measured RNAI and RNAII concentrations for DH5α-pSUP 201-3 reside between 6 ±0.7 to 34 ±7 RNAI molecules per cell and 0.44 ±0.1 to 3 ±0.9 RNAII molecules per cell. The determined plasmid copy numbers (PCN averaged between 46 ±26 to 48 ±30 plasmids per cell. The experimentally determined data for DH5α-pCMV-lacZ reside between 345 ±203 to 1086 ±298 RNAI molecules per cell and 22 ±2 to 75 ±10 RNAII molecules per cell with an averaged PCN of 1514 ±1301 to 5806 ±4828 depending on the measured time point. As the model was shown to be consistent with the experimentally determined data, measured at three different time points within the growth of the same strain, we performed predictive simulations concerning the effect of uncharged tRNA molecules on the ColE1-like plasmid replication control. The hypothesis is that these tRNA molecules would have an enhancing effect on the plasmid production. The in silico analysis predicts that uncharged tRNA molecules would indeed increase the pDNA production.

  11. Plasmid pGA1 from Corynebacterium glutamicum codes for a gene product that positively influences plasmid copy number.

    OpenAIRE

    Nesvera, J; Pátek, M; Hochmannová, J; Abrhámová, Z; Becvárová, V; Jelínkova, M; Vohradský, J

    1997-01-01

    The complete nucleotide sequence (4,826 bp) of the cryptic plasmid pGA1 from Corynebacterium glutamicum was determined. DNA sequence analysis revealed four putative coding regions (open reading frame A [ORFA], ORFA2, ORFB, and ORFC). ORFC was identified as a rep gene coding for an initiator of plasmid replication (Rep) according to the high level of homology of its deduced amino acid sequence with the Rep proteins of plasmids pSR1 (from C. glutamicum) and pNG2 (from Corynebacterium diphtheria...

  12. Developing strategies to increase plasmid DNA production in Escherichia coli DH5α using batch culture.

    Science.gov (United States)

    Islas-Lugo, Fabiola; Vega-Estrada, Jesús; Alvis, Christian Ariel; Ortega-López, Jaime; Del Carmen Montes-Horcasitas, María

    2016-09-10

    Plasmid DNA (pDNA) production has recently increased as a result of advances in DNA vaccines. The practical development of pDNA vaccines requires high yield and productivity of supercoiled plasmid DNA (sc-pDNA). The yield and productivity are influenced by the host strain, the plasmid, the production process, and especially by growth conditions, such as the culture type and medium. We evaluated different strategies to increase pDNA production by Escherichia coli DH5α in batch culture. The strategies were driven by the development of a four single-factor experimental design and were based on the change of culture media composition in terms of carbon and nitrogen and the modification of the pH control by using NaOH or NH4OH. The results revealed the carbon (50g/L of glycerol) and nitrogen (8.34g/L of YESP) concentration in the culture medium and starting pH control with NH4OH when most of the organic nitrogen was consumed. Under these conditions, we obtained a volumetric yield of 213mg pDNA/L, a specific yield of 10mg pDNA/g DCW (dry cell weight), 92% of sc-pDNA and a productivity of 17.6mg pDNA/(Lh). The pDNA productivities reached were 42% higher than the productivities reported by other authors applying similar conditions. PMID:27374404

  13. Selective pressure affects transfer and establishment of a Lactobacillus plantarum resistance plasmid in the gastrointestinal environment

    DEFF Research Database (Denmark)

    Feld, Louise; Schjorring, S.; Hammer, Karin;

    2008-01-01

    Objectives and methods: A Lactobacillus plantarum strain recently isolated from French raw-milk cheese was tested for its ability to transfer a small plasmid pLFE1 harbouring the erythromycin resistance gene erm(B) to Enterococcus faecalis. Mating was studied in vitro and in different gastrointes......Objectives and methods: A Lactobacillus plantarum strain recently isolated from French raw-milk cheese was tested for its ability to transfer a small plasmid pLFE1 harbouring the erythromycin resistance gene erm(B) to Enterococcus faecalis. Mating was studied in vitro and in different...

  14. Construction of plasmid-free Escherichia coli for the production of arabitol-free xylitol from corncob hemicellulosic hydrolysate

    OpenAIRE

    Buli Su; Zhe Zhang; Mianbin Wu; Jianping Lin; Lirong Yang

    2016-01-01

    High costs and low production efficiency are a serious constraint to bio-based xylitol production. For industrial-scale production of xylitol, a plasmid-free Escherichia coli for arabitol-free xylitol production from corncob hemicellulosic hydrolysate has been constructed. Instead of being plasmid and inducer dependent, this strain relied on multiple-copy integration of xylose reductase (XR) genes into the chromosome, where their expression was controlled by the constitutive promoter P43. In ...

  15. Factors that affect transfer of the IncI1 β-lactam resistance plasmid pESBL-283 between E. coli strains.

    Directory of Open Access Journals (Sweden)

    Nadine Händel

    Full Text Available The spread of antibiotic resistant bacteria worldwide presents a major health threat to human health care that results in therapy failure and increasing costs. The transfer of resistance conferring plasmids by conjugation is a major route by which resistance genes disseminate at the intra- and interspecies level. High similarities between resistance genes identified in foodborne and hospital-acquired pathogens suggest transmission of resistance conferring and transferrable mobile elements through the food chain, either as part of intact strains, or through transfer of plasmids from foodborne to human strains. To study the factors that affect the rate of plasmid transfer, the transmission of an extended-spectrum β-lactamase (ESBL plasmid from a foodborne Escherichia coli strain to the β-lactam sensitive E. coli MG1655 strain was documented as a function of simulated environmental factors. The foodborne E. coli isolate used as donor carried a CTX-M-1 harboring IncI1 plasmid that confers resistance to β-lactam antibiotics. Cell density, energy availability and growth rate were identified as factors that affect plasmid transfer efficiency. Transfer rates were highest in the absence of the antibiotic, with almost every acceptor cell picking up the plasmid. Raising the antibiotic concentrations above the minimum inhibitory concentration (MIC resulted in reduced transfer rates, but also selected for the plasmid carrying donor and recombinant strains. Based on the mutational pattern of transconjugant cells, a common mechanism is proposed which compensates for fitness costs due to plasmid carriage by reducing other cell functions. Reducing potential fitness costs due to maintenance and expression of the plasmid could contribute to persistence of resistance genes in the environment even without antibiotic pressure. Taken together, the results identify factors that drive the spread and persistence of resistance conferring plasmids in natural isolates

  16. Plasmid and Host Strain Characteristics of Escherichia coli Resistant to Extended-Spectrum Cephalosporins in the Norwegian Broiler Production.

    Science.gov (United States)

    Mo, Solveig Sølverød; Slettemeås, Jannice Schau; Berg, Einar Sverre; Norström, Madelaine; Sunde, Marianne

    2016-01-01

    Escherichia coli resistant to extended-spectrum cephalosporins have been detected in the Norwegian broiler production, despite the fact that antimicrobial agents are rarely used. The genetic mechanism responsible for cephalosporin resistance is mainly attributed to the presence of the blaCMY-2 gene encoding a plasmid-mediated AmpC-beta-lactamase (pAmpC). The aim of this study was to characterize and compare blaCMY-2 containing Escherichia coli isolated from the intestinal flora of broilers and retail chicken meat (fillets) to identify possible successful clones and/or resistance plasmids widespread in the Norwegian broiler production. Methods used included PCR based phylotyping, conjugation experiments, plasmid replicon typing, pulsed-field gel electrophoresis, multiple locus variable-number tandem-repeats analysis and whole genome sequencing. The nucleotide sequence of an IncK plasmid carrying blaCMY-2 was determined. Intestinal isolates displayed a higher degree of genetic diversity than meat isolates. A cluster of genetically related isolates belonging to ST38, phylogroup D, carrying blaCMY-2 containing IncK plasmids was identified. Furthermore, genes encoding plasmid stability systems (relBE/stbDE and pndAC) were identified on the IncK plasmid. Single nucleotide polymorphism (SNP) analysis of a subset of isolates confirmed a close genetic relationship within the two most prevalent STs. The IncK plasmids within these two STs also shared a high degree of similarity. Cephalosporin-resistant E. coli with the same genetic characteristics have been identified in the broiler production in other European countries, and the IncK plasmid characterized in this study showed close homology to a plasmid isolated from retail chicken meat in the Netherlands. The results indicate that both clonal expansion and horizontal transfer of blaCMY-2 containing plasmids contribute to dissemination of cephalosporin resistant E. coli in the broiler production. The presence of plasmid

  17. Plasmid and Host Strain Characteristics of Escherichia coli Resistant to Extended-Spectrum Cephalosporins in the Norwegian Broiler Production

    Science.gov (United States)

    Mo, Solveig Sølverød; Slettemeås, Jannice Schau; Berg, Einar Sverre; Norström, Madelaine; Sunde, Marianne

    2016-01-01

    Escherichia coli resistant to extended-spectrum cephalosporins have been detected in the Norwegian broiler production, despite the fact that antimicrobial agents are rarely used. The genetic mechanism responsible for cephalosporin resistance is mainly attributed to the presence of the blaCMY-2 gene encoding a plasmid-mediated AmpC-beta-lactamase (pAmpC). The aim of this study was to characterize and compare blaCMY-2 containing Escherichia coli isolated from the intestinal flora of broilers and retail chicken meat (fillets) to identify possible successful clones and/or resistance plasmids widespread in the Norwegian broiler production. Methods used included PCR based phylotyping, conjugation experiments, plasmid replicon typing, pulsed-field gel electrophoresis, multiple locus variable-number tandem-repeats analysis and whole genome sequencing. The nucleotide sequence of an IncK plasmid carrying blaCMY-2 was determined. Intestinal isolates displayed a higher degree of genetic diversity than meat isolates. A cluster of genetically related isolates belonging to ST38, phylogroup D, carrying blaCMY-2 containing IncK plasmids was identified. Furthermore, genes encoding plasmid stability systems (relBE/stbDE and pndAC) were identified on the IncK plasmid. Single nucleotide polymorphism (SNP) analysis of a subset of isolates confirmed a close genetic relationship within the two most prevalent STs. The IncK plasmids within these two STs also shared a high degree of similarity. Cephalosporin-resistant E. coli with the same genetic characteristics have been identified in the broiler production in other European countries, and the IncK plasmid characterized in this study showed close homology to a plasmid isolated from retail chicken meat in the Netherlands. The results indicate that both clonal expansion and horizontal transfer of blaCMY-2 containing plasmids contribute to dissemination of cephalosporin resistant E. coli in the broiler production. The presence of plasmid

  18. Effects of FP2 and a mercury resistance plasmid from Pseudomonas aeruginosa PA103 on exoenzyme production.

    OpenAIRE

    Johnson, J; Warren, R.L.; Branstrom, A A

    1991-01-01

    Plasmids encoding mercury resistance carried by Pseudomonas aeruginosa PAO1161 and PA103 were found to be involved in regulating the secretion of protease, phospholipase C, and alkaline phosphatase. Previously, mutations in Pseudomonas strains that caused pleiotropic effects on the production of extracellular enzymes were mapped to the bacterial chromosome. We show that pleiotropic changes in extracellular enzyme production can also be regulated by plasmids. In this study, the effects on secr...

  19. Construction of plasmid-free Escherichia coli for the production of arabitol-free xylitol from corncob hemicellulosic hydrolysate.

    Science.gov (United States)

    Su, Buli; Zhang, Zhe; Wu, Mianbin; Lin, Jianping; Yang, Lirong

    2016-01-01

    High costs and low production efficiency are a serious constraint to bio-based xylitol production. For industrial-scale production of xylitol, a plasmid-free Escherichia coli for arabitol-free xylitol production from corncob hemicellulosic hydrolysate has been constructed. Instead of being plasmid and inducer dependent, this strain relied on multiple-copy integration of xylose reductase (XR) genes into the chromosome, where their expression was controlled by the constitutive promoter P43. In addition, to minimize the flux from L-arabinose to arabitol, two strategies including low XR total activity and high selectivity of XR has been adopted. Arabitol was significantly decreased using plasmid-free strain which had lower XR total activity and an eight point-mutations of XR with a 27-fold lower enzyme activity toward L-arabinose was achieved. The plasmid-free strain in conjunction with this mutant XR can completely eliminate arabitol formation in xylitol production. In fed-batch fermentation, this plasmid-free strain produced 143.8 g L(-1) xylitol at 1.84 g L(-1) h(-1) from corncob hemicellulosic hydrolysate. From these results, we conclude that this route by plasmid-free E. coli has potential to become a commercially viable process for xylitol production. PMID:27225023

  20. Increasing plasmid-based DNA vaccine construct (16 kb pSVK-HBVA) production in Escherichia coli XL10-Gold through optimization of media component

    OpenAIRE

    Wang, Yu; Zhang, Liang; Zhang, Wei; Wu, Hao; Zhu, Xiao Ming; Xu, Yuan Ji; Yan, Jin Qi; Yu, Ji Yun

    2015-01-01

    At present, there are production processes to produce protein by Escherichia coli (E. coli) fermentation. Research on the design and optimization of the plasmid fermentation medium, however, is less advanced. The fermentation medium that is optimized for plasmid DNA production is different from the medium that is optimized for protein production. So, establishing a scientific and rational method to optimize the fermentation medium used for plasmid production is very important. Previously, our...

  1. A Transient Three-plasmid Expression System for the Production of Hepatocytes Targeting Retroviral Vectors

    Institute of Scientific and Technical Information of China (English)

    Peng QI; Jinxiang HAN; Yanqin LU; Chuanxi WANG; Bo ZHU

    2007-01-01

    Targeting of retroviral vectors to specific cells was attempted through modifying the surface protein of the murine leukemia viruses (MLVs), but in many cases the protein function was affected, and it is difficult to achieve the targeted delivery. In this study, we have tried to engineer ecotropic Moloney murine leukemia viruses (MoMLV)-based retroviral vectors to transduce hepatocytes. A chimeric envelope (Env)expression plasmid was constructed containing the hepatitis B virus PreS2 peptide fused to aa +1 at the Nterminus of Env. Following simultaneous transfection of pgag-pol, pLEGFP and chimeric env plasmids into 293T cells, helper-free retrovirus stocks with the titer of approximately 104 infectious units/ml were achieved at 48 h post-transfection. These pseudotype vectors showed the normal host range of retrovirus, infecting host NIH 3T3 cells, although the efficiency was reduced compared with that of virions carrying wild-type ecotropic MoMLV envelope. In addition, the resultant pseudotype viruses could transduce human hepatoma cells mediated by polymerized human serum albumin with relatively high titers in comparison with those transductions without polymerized human serum albumin. This approach can be used to target hepatocytes selectively.

  2. A cell engineering strategy to enhance supercoiled plasmid DNA production for gene therapy

    OpenAIRE

    Hassan, S.; Keshavarz-Moore, E.; J. Ward

    2016-01-01

    With the recent revival of the promise of plasmid DNA vectors in gene therapy, a novel synthetic biology approach was used to enhance the quantity, (yield), and quality of the plasmid DNA. Quality was measured by percentage supercoiling and supercoiling density, as well as improving segregational stability in fermentation. We examined the hypothesis that adding a Strong Gyrase binding Site (SGS) would increase DNA gyrase-mediated plasmid supercoiling. SGS from 3 different replicons, (the Mu b...

  3. How Employee Turnover Affects Productivity

    DEFF Research Database (Denmark)

    Eriksen, Bo

    Research on employee turnover suggests that turnover results in negative organization-level outcomes. This paper provides a firm-level analysis of the impact of the in- and outflows of human resources on productivity and how the presence of organizational slack resources moderates the effects of...... employee turnover. Drawing on a unique longitudinal dataset of 2,926 Danish manufacturing firms that combine individual-level data with firm-level data, the paper shows that job turnover has a substantial negative effect on total productivity but that the firm’s size, its capital intensity, and its age...... moderate this effect so that the negative consequences of employee turnover are less severe for larger, older and capital intensive firms. These moderating variables indicate the presence of slack resources in the firm, and thus that the accumulation of slack reduces the efficiency losses from employee...

  4. How Employee Turnover Affects Productivity

    DEFF Research Database (Denmark)

    Eriksen, Bo

    employee turnover. Drawing on a unique longitudinal dataset of 2,926 Danish manufacturing firms that combine individual-level data with firm-level data, the paper shows that job turnover has a substantial negative effect on total productivity but that the firm’s size, its capital intensity, and its age...... moderate this effect so that the negative consequences of employee turnover are less severe for larger, older and capital intensive firms. These moderating variables indicate the presence of slack resources in the firm, and thus that the accumulation of slack reduces the efficiency losses from employee...

  5. Production of 2-ketoisocaproate with Corynebacterium glutamicum strains devoid of plasmids and heterologous genes.

    Science.gov (United States)

    Vogt, Michael; Haas, Sabine; Polen, Tino; van Ooyen, Jan; Bott, Michael

    2015-03-01

    2-Ketoisocaproate (KIC), the last intermediate in l-leucine biosynthesis, has various medical and industrial applications. After deletion of the ilvE gene for transaminase B in l-leucine production strains of Corynebacterium glutamicum, KIC became the major product, however, the strains were auxotrophic for l-isoleucine. To avoid auxotrophy, reduction of IlvE activity by exchanging the ATG start codon of ilvE by GTG was tested instead of an ilvE deletion. The resulting strains were indeed able to grow in glucose minimal medium without amino acid supplementation, but at the cost of lowered growth rates and KIC production parameters. The best production performance was obtained with strain MV-KICF1, which carried besides the ilvE start codon exchange three copies of a gene for a feedback-resistant 2-isopropylmalate synthase, one copy of a gene for a feedback-resistant acetohydroxyacid synthase and deletions of ltbR and iolR encoding transcriptional regulators. In the presence of 1 mM l-isoleucine, MV-KICF1 accumulated 47 mM KIC (6.1 g l(-1)) with a yield of 0.20 mol/mol glucose and a volumetric productivity of 1.41 mmol KIC l(-1)  h(-1). Since MV-KICF1 is plasmid free and lacks heterologous genes, it is an interesting strain for industrial application and as platform for the production of KIC-derived compounds, such as 3-methyl-1-butanol. PMID:25488800

  6. Studies on the plasmid stability, plasmid copy number and endo(1, 3)(1, 4) b-glucanase production by free and alginate immobilised recombinant saccharomyces cerevisiae cells

    OpenAIRE

    Canavan, Peter D.

    1994-01-01

    A recombinant yeast strain, Saccharomyces cerevisiae DBY746, containing the plasmid pJG317, was grown in a variety of fermentation modes including batch, serial batch and chemostat culture incorporating a wide range of media types Plasmid pJG317 consists of a 2^-denved yeast episomal plasmid containing the gene which encodes for the bacterial enzyme endo (1,3)(1,4) P-glucanase. The concentration of enzyme produced appears to be proportional to the number of plasmid copies per cell. Specific e...

  7. Production of clinical-grade plasmid DNA for human Phase I clinical trials and large animal clinical studies.

    Science.gov (United States)

    Przybylowski, Mark; Bartido, Shirley; Borquez-Ojeda, Oriana; Sadelain, Michel; Rivière, Isabelle

    2007-06-28

    The use of plasmid DNA as vaccines for the treatment of cancer and infectious diseases is on the rise. In order to facilitate the manufacture of clinical-grade plasmid DNA for Phase I clinical trials, we developed a process whereby >200 mg plasmid could be produced in a single production run under Good Manufacturing Practices. A dedicated cleanroom (Class 10,000 with Class 100 biosafety cabinet) is utilized for production of the bacterial cell bank, fermentation, harvest/lysis of the biomass, and downstream purification. Fermentation requires three 16-18 h runs (approximately 12 L each) in shaker-flasks, yielding approximately 60 g bacterial paste following batch centrifugation. The biomass is alkaline-lysed, pooled, and the resulting flocculent precipitate is separated by a novel vacuum step, followed by depth-filtration. Downstream processing includes anion-exchange chromatography, utilizing Qiagen silica-based resin, and precipitation with isopropanol. Following precipitation, the DNA is harvested by centrifugation, dried, formulated, and sterile-filtered using a Sartorius Sartobran 150 filter prior to Final-Filling. All processing steps utilize sterilized, single-use components. This process results in a product manufactured according to regulatory guidelines. The plasmid DNA is sterile with >or=95% supercoiled DNA, an A260/A280 ratio>or=1.9, undetectable or extremely low residual endotoxin, RNA, genomic DNA, protein, and antibiotic. Residual solvent levels are negligible. The product yields the predicted profile upon restriction-enzyme digestion, is biologically active upon transfection and remains stable for several years at -20 degrees C. We have therefore developed a reproducible and cost effective process to manufacture clinical-grade plasmid DNA. This process can be adapted by other academic centers for human or large animal clinical trials. PMID:17537555

  8. A Transposable Partitioning Locus Used To Stabilize Plasmid-Borne Hydrogen Oxidation and Trifolitoxin Production Genes in a Sinorhizobium Strain

    OpenAIRE

    Kent, Angela D.; Wojtasiak, Michelle L.; Robleto, Eduardo A.; Eric W Triplett

    1998-01-01

    Improved nitrogen-fixing inoculum strains for leguminous crops must be able to effectively compete with indigenous strains for nodulation, enhance legume productivity compared to the productivity obtained with indigenous strains, and maintain stable expression of any added genes in the absence of selection pressure. We constructed a transposable element containing the tfx region for expression of increased nodulation competitiveness and the par locus for plasmid stability. The transposon was ...

  9. Rational plasmid design and bioprocess optimization to enhance recombinant adeno-associated virus (AAV) productivity in mammalian cells.

    Science.gov (United States)

    Emmerling, Verena V; Pegel, Antje; Milian, Ernest G; Venereo-Sanchez, Alina; Kunz, Marion; Wegele, Jessica; Kamen, Amine A; Kochanek, Stefan; Hoerer, Markus

    2016-02-01

    Viral vectors used for gene and oncolytic therapy belong to the most promising biological products for future therapeutics. Clinical success of recombinant adeno-associated virus (rAAV) based therapies raises considerable demand for viral vectors, which cannot be met by current manufacturing strategies. Addressing existing bottlenecks, we improved a plasmid system termed rep/cap split packaging and designed a minimal plasmid encoding adenoviral helper function. Plasmid modifications led to a 12-fold increase in rAAV vector titers compared to the widely used pDG standard system. Evaluation of different production approaches revealed superiority of processes based on anchorage- and serum-dependent HEK293T cells, exhibiting about 15-fold higher specific and volumetric productivity compared to well-established suspension cells cultivated in serum-free medium. As for most other viral vectors, classical stirred-tank bioreactor production is thus still not capable of providing drug product of sufficient amount. We show that manufacturing strategies employing classical surface-providing culture systems can be successfully transferred to the new fully-controlled, single-use bioreactor system Integrity(TM) iCELLis(TM) . In summary, we demonstrate substantial bioprocess optimizations leading to more efficient and scalable production processes suggesting a promising way for flexible large-scale rAAV manufacturing. PMID:26284700

  10. A cell engineering strategy to enhance supercoiled plasmid DNA production for gene therapy.

    Science.gov (United States)

    Hassan, Sally; Keshavarz-Moore, Eli; Ward, John

    2016-09-01

    With the recent revival of the promise of plasmid DNA vectors in gene therapy, a novel synthetic biology approach was used to enhance the quantity, (yield), and quality of the plasmid DNA. Quality was measured by percentage supercoiling and supercoiling density, as well as improving segregational stability in fermentation. We examined the hypothesis that adding a Strong Gyrase binding Site (SGS) would increase DNA gyrase-mediated plasmid supercoiling. SGS from three different replicons, (the Mu bacteriophage and two plasmids, pSC101 and pBR322) were inserted into the plasmid, pUC57. Different sizes of these variants were transformed into E. coli DH5α, and their supercoiling properties and segregational stability measured. A 36% increase in supercoiling density was found in pUC57-SGS, but only when SGS was derived from the Mu phage and was the larger sized version of this fragment. These results were also confirmed at fermentation scale. Total percentage supercoiled monomer was maintained to 85-90%. A twofold increase in plasmid yield was also observed for pUC57-SGS in comparison to pUC57. pUC57-SGS displayed greater segregational stability than pUC57-cer and pUC57, demonstrating a further potential advantage of the SGS site. These findings should augment the potential of plasmid DNA vectors in plasmid DNA manufacture. Biotechnol. Bioeng. 2016;113: 2064-2071. © 2016 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc. PMID:26928284

  11. A transient three-plasmid expression system for the production of high titer retroviral vectors.

    OpenAIRE

    Soneoka, Y; Cannon, P M; Ramsdale, E E; Griffiths, J C; Romano, G.; Kingsman, S M; Kingsman, A J

    1995-01-01

    We have constructed a series of MLV-based retroviral vectors and packaging components expressed from the CMV promoter and carried on plasmids containing SV40 origins of replication. These two features greatly enhanced retroviral gene expression when introduced into cell lines carrying the SV40 large T antigen. The two packaging components, gag-pol and env, were placed on separate plasmids to reduce helper virus formation. Using a highly transfectable human cell line and sodium butyrate to fur...

  12. Plasmid and Host Strain Characteristics of Escherichia coli Resistant to Extended-Spectrum Cephalosporins in the Norwegian Broiler Production

    OpenAIRE

    Solveig Sølverød Mo; Jannice Schau Slettemeås; Einar Sverre Berg; Madelaine Norström; Marianne Sunde

    2016-01-01

    Escherichia coli resistant to extended-spectrum cephalosporins have been detected in the Norwegian broiler production, despite the fact that antimicrobial agents are rarely used. The genetic mechanism responsible for cephalosporin resistance is mainly attributed to the presence of the bla CMY-2 gene encoding a plasmid-mediated AmpC-beta-lactamase (pAmpC). The aim of this study was to characterize and compare bla CMY-2 containing Escherichia coli isolated from the intestinal flora of broilers ...

  13. Turbo cloning: a fast, efficient method for cloning PCR products and other blunt-ended DNA fragments into plasmids.

    OpenAIRE

    Boyd, A C

    1993-01-01

    The method uses a novel plasmid vector, p9lox5, containing a site-specific recombination sequence lox from the lox/Cre recombinase system of bacteriophage P1. There are two distinct stages. Firstly, vector and fragment DNAs are ligated intermolecularly under conditions of macromolecular crowding (15% polyethylene glycol 6000) which accelerate blunt-end joining a thousandfold. Secondly, circular recombinant molecules are efficiently excised from the ligation products by Cre recombinase acting ...

  14. A plasmid in the archaebacterium Sulfolobus acidocaldarius

    OpenAIRE

    Yeats, Siobhán; McWilliam, Peter; Zillig, Wolfram

    1982-01-01

    A plasmid of mol. wt. ∼9 × 106 has been isolated from the archaebacterium Sulfolobus acidocaldarius strain B12. Plasmid production is induced by u.v. radiation. A copy of the plasmid is probably carried by the chromosome, integrated at a specific site. The entire plasmid, and also restriction fragments of it, has been cloned into Escherichia coli plasmid vectors, and the cleavage sites on the plasmid DNA of three restriction endonucleases have been mapped.

  15. Does Labour Diversity affect Firm Productivity?

    DEFF Research Database (Denmark)

    Parrotta, Pierpaolo; Pozzoli, Dario; Pytlikova, Mariola

    that labor diversity in education significantly enhances a firm's value added. Conversely, diversity in ethnicity and demographics induces negative effects on firm productivity. Hence, the negative effects, coming from communication and integration costs connected to a more culturally and demographically......Using a matched employer-employee dataset, we analyze how workforce diversity in cultural background, education and demographic characteristics affects productivity of firms in Denmark. Implementing a structural estimation of the firms' production function (Ackerberg et al., 2006) we find...

  16. A transient three-plasmid expression system for the production of high titer retroviral vectors.

    Science.gov (United States)

    Soneoka, Y; Cannon, P M; Ramsdale, E E; Griffiths, J C; Romano, G; Kingsman, S M; Kingsman, A J

    1995-02-25

    We have constructed a series of MLV-based retroviral vectors and packaging components expressed from the CMV promoter and carried on plasmids containing SV40 origins of replication. These two features greatly enhanced retroviral gene expression when introduced into cell lines carrying the SV40 large T antigen. The two packaging components, gag-pol and env, were placed on separate plasmids to reduce helper virus formation. Using a highly transfectable human cell line and sodium butyrate to further increase expression of each component, we achieved helper-free viral stocks of approximately 10(7) infectious units/ml by 48 h after transient co-transfection with the three plasmid components. This system can be used both for the generation of high titer retroviral stocks for transduction and for the rapid screening of a large number of MLV gag-pol or env mutants. PMID:7899083

  17. Maximizing Plasmid Stability and Production of Released Proteins in Yersinia enterocolitica

    OpenAIRE

    Li, Huaiyu; Bhaduri, Saumya; Magee, Wayne E.

    1998-01-01

    Virulent serotypes of Yersinia enterocolitica carry a plasmid (pYV) encoding a family of proteins that are released into the medium and whose expression is temperature and calcium regulated. The plasmid is easily lost from cells during their growth in the laboratory. We have used sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting with a monoclonal antibody (3.2C) that is specific for a 25-kDa released protein to show that 32°C is the lowest temperature at which pla...

  18. Enhancing functional production of a chaperone-dependent lipase in Escherichia coli using the dual expression cassette plasmid

    Directory of Open Access Journals (Sweden)

    Quyen Thi Dinh

    2012-03-01

    Full Text Available Abstracts Background The lipase subfamilies I.1 and I.2 show more than 33% homology in the amino acid sequences and most members share another common property that their genes are clustered with the secondary genes whose protein products are required for folding the lipase into an active conformation and secretion into the culture medium. In previous studies, the lipase (LipA and its chaperone (LipB from Ralstonia sp. M1 were overexpressed in E. coli and the lipase was successfully refolded in vitro. The purpose of this study was to enhance the production of the active lipase LipA from Ralstonia sp. M1 in the heterologous host E. coli without in vitro refolding process, using two-plasmid co-expression systems and dual expression cassette plasmid systems. Results To produce more active lipase from Ralstonia sp. M1 in E. coli without in vitro refolding process but with the help of overexpression of the chaperone (LipB1 and LipB3 corresponding to 56-aa truncated and 26-aa truncated chaperone LipB, six different expression systems including 2 two-plasmid co-expression systems (E. coli BL21/pELipABa + pELipB1k and BL21/pELipABa + pELipB3k and 4 dual expression cassette plasmid systems (BL21/pELipAB-LipB1a, BL21/pELipAB-LipB3a, BL21/pELipA-LipB1a, and BL21/pELipA-LipB3a were constructed. The two-plasmid co-expression systems (E. coli BL21/pELipABa + pELipB1k and BL21/pELipABa + pELipB3k produced the active lipase at a level of 4 times as high as the single expression cassette plasmid system E. coli BL21/pELipABa did. For the first time, the dual expression cassette plasmid systems BL21/pELipAB-LipB1a and BL21/pELipAB-LipB3a yielded 29- and 19-fold production of the active lipase in comparison with the single expression cassette plasmid system E. coli BL21/pELipABa, respectively. Although the lipase amount was equally expressed in all these expression systems (40% of total cellular protein and only a small fraction of the overexpressed lipase was

  19. The marketing implications of affective product design.

    Science.gov (United States)

    Seva, Rosemary R; Duh, Henry Been-Lirn; Helander, Martin G

    2007-11-01

    Emotions are compelling human experiences and product designers can take advantage of this by conceptualizing emotion-engendering products that sell well in the market. This study hypothesized that product attributes influence users' emotions and that the relationship is moderated by the adherence of these product attributes to purchase criteria. It was further hypothesized that the emotional experience of the user influences purchase intention. A laboratory study was conducted to validate the hypotheses using mobile phones as test products. Sixty-two participants were asked to assess eight phones from a display of 10 phones and indicate their emotional experiences after assessment. Results suggest that some product attributes can cause intense emotional experience. The attributes relate to the phone's dimensions and the relationship between these dimensions. The study validated the notion of integrating affect in designing products that convey users' personalities. PMID:17303064

  20. Integral parametrization of the Kinetics of Crosslink production in plasmid DNA as a function of 8-methoxypsoralen concentration

    International Nuclear Information System (INIS)

    In this paper we present results of crosslink production in pBR322 DNA along a wide range of 8-methoxypsoralen (8-MOP) concentration. Experimental data were obtained as DNA renaturation percentages, from the shift in hyperchromicity after a temperature-dependent denaturation-renaturation process. the experimental results showed a three-stage profile when represented as a function of the natural logarithms of 8-MOP concentration. an integral parametrization which allows a simultaneous fit of the three observed stages is presented here. the theoretical values of crosslink production determined from the fit are useful to asses the genotoxicity of psoralen-induced crosslinks in plasmid DNA. (Author) 24 refs

  1. Integral parametrization of the Kinetics of Crosslink production in plasmid DNA as a function of 8-methoxypsoralen concentration

    Energy Technology Data Exchange (ETDEWEB)

    Vidania, R. de; Paramio, J. M.; Bauluz, C.

    1986-07-01

    In this paper we present results of crosslink production in pBR322 DNA along a wide range of 8-methoxypsoralen (8-MOP) concentration. Experimental data were obtained as DNA renaturation percentages, from the shift in hyperchromicity after a temperature-dependent denaturation-renaturation process. the experimental results showed a three-stage profile when represented as a function of the natural logarithms of 8-MOP concentration. an integral parametrization which allows a simultaneous fit of the three observed stages is presented here. the theoretical values of crosslink production determined from the fit are useful to asses the genotoxicity of psoralen-induced crosslinks in plasmid DNA. (Author) 24 refs.

  2. Integral parametrization of the kinetics of crosslink production in plasmid DNA as a function of 8-methoxypsoralen concentration

    International Nuclear Information System (INIS)

    The results of crosslink production in pBR322 DNA along a wide range of 8-methoxypsoralen (8 MOP) concentration are presented. Experimental data were obtained as DNA renaturation percentages, from the shift in hyperchromicity after a temperature-dependent denaturation-renaturation process. The experimental results showed a three-stage profile when represented as a function of the natural logarithm of 8-MOP concentration. An integral parametrization which allows a simultaneous fit of the three observed stages is presented here. The theoretical values of crosslink production determined from the fit are useful to assess the genotoxicity of psoralen-induced crosslinks in plasmid DNA. (author)

  3. Does Labor Diversity Affect Firm Productivity?

    OpenAIRE

    Parrotta, Pierpaolo; Pozzoli, Dario; Pytlikova, Mariola

    2010-01-01

    Using an employer-employee dataset, we analyze how diversity in cultural background, skills and demographic characteristics affects total factor productivity (TFP) of firms in Denmark. Implementing structural estimation of firms’ production function, we find evidence that labor diversity in skills/education significantly enhances firm performance as measured by firm TFP. Conversely, diversity in demographics and ethnicity brings mixed results – both dimensions of workforce diversity have eith...

  4. Resveratrol production in bioreactor: Assessment of cell physiological states and plasmid segregational stability

    OpenAIRE

    Margarida S. Afonso; Susana Ferreira; Domingues, Fernanda C.; Filomena Silva

    2015-01-01

    Resveratrol is a plant secondary metabolite commonly found in peanuts and grapevines with significant health benefits. Recombinant organisms can produce large amounts of resveratrol and, in this work, Escherichia coli BW27784 was used to produce resveratrol in bioreactors while monitoring cell physiology and plasmid stability through flow cytometry and real-time qPCR, respectively. Initially, the influence of culture conditions and precursor addition was evaluated in screening assays and the ...

  5. Empirical Study on Factors Affecting Biogas Production

    OpenAIRE

    Prasad, Ravita D.

    2012-01-01

    In Fiji, biogas has a huge potential to be one of the energy providers for cooking in rural areas but currently its use is very minimal. Main component of biogas is methane which releases energy when combusted. This paper mainly presents the factors that affect biogas production using experimental study. The first section presents an overview on what is biogas, types of biogas digesters present, and some background on the current use of biogas in Fiji. The second section of the paper describe...

  6. Effects of a recombinant gene expression on ColE1-like plasmid segregation in Escherichia coli

    OpenAIRE

    Ivanov Ivan; Nacheva Genoveva; Petrov Stefan; Popov Mladen; Reichl Udo

    2011-01-01

    Abstract Background Segregation of expression plasmids leads to loss of recombinant DNA from transformed bacterial cells due to the irregular distribution of plasmids between the daughter cells during cell division. Under non-selective conditions this segregational instability results in a heterogeneous population of cells, where the non-productive plasmid-free cells overgrow the plasmid-bearing cells thus decreasing the yield of recombinant protein. Amongst the factors affecting segregationa...

  7. Strain- and plasmid-level deconvolution of a synthetic metagenome by sequencing proximity ligation products.

    Science.gov (United States)

    Beitel, Christopher W; Froenicke, Lutz; Lang, Jenna M; Korf, Ian F; Michelmore, Richard W; Eisen, Jonathan A; Darling, Aaron E

    2014-01-01

    Metagenomics is a valuable tool for the study of microbial communities but has been limited by the difficulty of "binning" the resulting sequences into groups corresponding to the individual species and strains that constitute the community. Moreover, there are presently no methods to track the flow of mobile DNA elements such as plasmids through communities or to determine which of these are co-localized within the same cell. We address these limitations by applying Hi-C, a technology originally designed for the study of three-dimensional genome structure in eukaryotes, to measure the cellular co-localization of DNA sequences. We leveraged Hi-C data generated from a simple synthetic metagenome sample to accurately cluster metagenome assembly contigs into groups that contain nearly complete genomes of each species. The Hi-C data also reliably associated plasmids with the chromosomes of their host and with each other. We further demonstrated that Hi-C data provides a long-range signal of strain-specific genotypes, indicating such data may be useful for high-resolution genotyping of microbial populations. Our work demonstrates that Hi-C sequencing data provide valuable information for metagenome analyses that are not currently obtainable by other methods. This metagenomic Hi-C method could facilitate future studies of the fine-scale population structure of microbes, as well as studies of how antibiotic resistance plasmids (or other genetic elements) mobilize in microbial communities. The method is not limited to microbiology; the genetic architecture of other heterogeneous populations of cells could also be studied with this technique. PMID:24918035

  8. Strain- and plasmid-level deconvolution of a synthetic metagenome by sequencing proximity ligation products

    Directory of Open Access Journals (Sweden)

    Christopher W. Beitel

    2014-05-01

    Full Text Available Metagenomics is a valuable tool for the study of microbial communities but has been limited by the difficulty of “binning” the resulting sequences into groups corresponding to the individual species and strains that constitute the community. Moreover, there are presently no methods to track the flow of mobile DNA elements such as plasmids through communities or to determine which of these are co-localized within the same cell. We address these limitations by applying Hi-C, a technology originally designed for the study of three-dimensional genome structure in eukaryotes, to measure the cellular co-localization of DNA sequences. We leveraged Hi-C data generated from a simple synthetic metagenome sample to accurately cluster metagenome assembly contigs into groups that contain nearly complete genomes of each species. The Hi-C data also reliably associated plasmids with the chromosomes of their host and with each other. We further demonstrated that Hi-C data provides a long-range signal of strain-specific genotypes, indicating such data may be useful for high-resolution genotyping of microbial populations. Our work demonstrates that Hi-C sequencing data provide valuable information for metagenome analyses that are not currently obtainable by other methods. This metagenomic Hi-C method could facilitate future studies of the fine-scale population structure of microbes, as well as studies of how antibiotic resistance plasmids (or other genetic elements mobilize in microbial communities. The method is not limited to microbiology; the genetic architecture of other heterogeneous populations of cells could also be studied with this technique.

  9. Penicillinase plasmid-linked genetic determinants for enterotoxins B and C1 production in Staphylococcus aureus.

    OpenAIRE

    Altboum, Z; Hertman, I; Sarid, S

    1985-01-01

    The genes encoding for beta-lactamase (bla+) and resistance to metallic ions (cadmium, mercury, lead, arsenate, and arsenite) were located in a 56.2-kilobase plasmid, pZA10, isolated from a clinical strain, Staphylococcus aureus 6344. This strain produced enterotoxin B and enterotoxin C1. Elimination of pZA10 by either sodium dodecyl sulfate or heat treatment (43 degrees C) resulted in the loss of the capability of the bacteria to produce both enterotoxin B and enterotoxin C1. A physical map ...

  10. Neonatal intramuscular injection of plasmid encoding glucagon-like peptide-1 affects anxiety behaviour and expression of the hippocampal glucocorticoid receptor in adolescent rats

    Indian Academy of Sciences (India)

    Huitao Fan; Lina Wang; Feng Guo; Shi Wei; Ruqian Zhao

    2010-03-01

    Early-life endocrine intervention may programme hippocampal glucocorticoid receptor (GR) expression and cause psychiatric disorders in later life. Glucagon-like peptide-1 (GLP-1) has been implicated in the regulation of neuroendocrine and behavioural responses, but it is yet to be determined whether and how neonatal GLP-1 overexpression may modify hippocampal GR expression and thus programme adolescent behaviour in rats. Two-dayold pups were injected intramuscularly with vacant plasmid (VP) or plasmid DNA encoding secretory GLP-1 (GP). Anxiety-related behaviour was assessed in the elevated plus maze (EPM) test at 8 weeks of age. Plasma corticosterone levels were measured with enzyme immunoassay (EIA). Protein and mRNA levels were determined by western blot and real-time polymerase chain reaction (PCR), respectively. The DNA methylation status of the GR exon 17 promoter was determined by bisulphate sequencing PCR (BSP). GP rats exhibited anxiolytic behaviour compared with their VP counterparts. Hippocampal GLP-1 receptor (GLP-1R) and GR mRNA expression were significantly elevated in GP rats without a significant difference in plasma corticosterone. Significant reduction in DNA methyltransferase 1 (DNMT1) expression was observed in GP rats disconnected with alterations in DNA methylation of the GR exon 17 promoter. Nevertheless, mRNA expression of nerve growth factor-inducible protein A (NGFI-A) was significantly elevated in GP rats. These results suggest that neonatal intramuscular injection of plasmid DNA encoding GLP-1 affects anxiety behaviour in adolescent rats, probably through NGFI-A-activated upregulation of hippocampal GR expression.

  11. Factors Affecting Sugarcane Production in Pakistan

    Directory of Open Access Journals (Sweden)

    Adnan Nazir

    2013-05-01

    Full Text Available This study was undertaken to identify the factors affecting sugarcane production in Pakistan. Data were collected from 387 sugarcane growers from Sindh, Punjab and NWFP province. Data were collected during the period 2007-08. The study reveals that the costs of inputs of sugarcane i.e. urea, DAP, FYM, land preparation, seed and its application, weeding and cost of irrigation were the important factors which influenced on the returns of sugarcane growers. The effectiveness was examined by using the Cobb-Douglas production function; MVP and allocative efficiency were calculated. The coefficient of multiple determinations R2 was 0.9249, which indicated that 92% variation in the cost of inputs was explained by all explanatory variables and the adjusted R2 was 92%. The F-value was 666.94 and was highly significant at 5% level of significance, indicating that the regression model was well fitted. The high prices of inputs, low price of output, delay in payments and lack of scientific knowledge were the major problems in sugarcane production. In order to enhance the productivity of sugarcane in the country, government should solve the identified problems to increase the income of sugarcane growers.

  12. Persistence Mechanisms of Conjugative Plasmids

    DEFF Research Database (Denmark)

    Bahl, Martin Iain; Hansen, Lars H.; Sørensen, Søren Johannes

    2009-01-01

    maintenance in the host cell. These importantly include the ability to self-mobilize in a process termed conjugative transfer, which may occur across species barriers. Other plasmid stabilizing mechanisms include the multimer resolution system, active partitioning, and post-segregational-killing of plasmid......Are plasmids selfish parasitic DNA molecules or an integrated part of the bacterial genome? This chapter reviews the current understanding of the persistence mechanisms of conjugative plasmids harbored by bacterial cells and populations. The diversity and intricacy of mechanisms affecting the...... successful propagation and long-term continued existence of these extra-chromosomal elements is extensive. Apart from the accessory genetic elements that may provide plasmid-harboring cells a selective advantage, special focus is placed on the mechanisms conjugative plasmids employ to ensure their stable...

  13. Plasmid DNA studies in Lactobacillus plantarum strains isolated from olive fermentations: production of and immunity to plantaricin OL15 is associated to a 9.6 Kb plasmid (pOL15

    Directory of Open Access Journals (Sweden)

    Mourad, Kacem

    2007-06-01

    Full Text Available Previously 12 Lactobacillus plantarum strains were isolated from fermented olives. Among these, only L. plantarum OL15 produced bacteriocin (plantaricin OL15. In this study, the 12 strains were examined for plasmid DNA content. Of these, 9 strains have shown one to three plasmid bands ranging in size from 5.4 to 12.2 kb. L. plantarum OL15 exhibited one plasmid (9.6 kb which was named pOL15. After curing with novobiocin and ethidium bromide, the plasmid profile analysis of non producing derivatives, showed that the 9.6 kb plasmid pOL15 harbored by the parental strain had been lost in all cases and none of them regained the ability to produce plantaricin OL15 suggesting that the production of plantaricin OL15 is plasmid linked. Plantaricin OL15 was not inactived by amylase and lipase suggesting that plantaricin OL15 activity was not dependent on the presence of either a carbohydrate or lipid moiety. Plantaricin OL15 showed activity against lactic acid bacteria of different species and also against olive spoilage and phytopathogenic bacteria, including Pseudomonas and Erwinia.En un estudio previo, se aislaron 12 cepas de Lactobacillus plantarum a partir de aceitunas fermentadas. Entre ellas, solo L. plantarum OL15 produjo bacteriocinas (plantaricin OL15. En este estudio, se examinó el contenido de AND plásmido en las 12 cepas citadas. Entre ellas, 9 cepas han mostrado de una a tres bandas de plásmido con tamaños en el rango de 5.4 a 12.2 kb. L. plantarum OL15 exhibió un plásmido (9.6 kb que se denominó pOL15. Después del curado con novobiocina y bromuro de etidio, la pérdida del plásmido pOL15 asociada a la pérdida de su facultad para producir plantaricin OL15, sugiere que la producción de plantaricina OL15 está ligada al plásmido. La plantaricin OL15 no se inactivó por amilasa ni por lipasa sugiriendo que su actividad no es dependiente de la presencia de carbohidratos o lípidos. La plantaricina OL15 mostró actividad frente a

  14. Use of FabV-Triclosan Plasmid Selection System for Efficient Expression and Production of Recombinant Proteins in Escherichia coli

    OpenAIRE

    Ali, Syed A.; Yik Wei Chew; Tasyriq Che Omar; Nizuwan Azman

    2015-01-01

    Maintenance of recombinant plasmid vectors in host bacteria relies on the presence of selection antibiotics in the growth media to suppress plasmid -free segregants. However, presence of antibiotic resistance genes and antibiotics themselves is not acceptable in several applications of biotechnology. Previously, we have shown that FabV-Triclosan selection system can be used to select high and medium copy number plasmid vectors in E. coli. Here, we have extended our previous work and demonstra...

  15. Telomere-Mediated Plasmid Segregation in Saccharomyces Cerevisiae Involves Gene Products Required for Transcriptional Repression at Silencers and Telomeres

    OpenAIRE

    Longtine, M. S.; Enomoto, S.; Finstad, S L; Berman, J

    1993-01-01

    Plasmids that contain Saccharomyces cerevisiae TG(1-3) telomere repeat sequences (TRS plasmids) segregate efficiently during mitosis. Mutations in histone H4 reduce the efficiency of TRS-mediated plasmid segregation, suggesting that chromatin structure is involved in this process. Sir2, Sir3 and Sir4 are required for the transcriptional repression of genes located at the silent mating type loci (HML and HMR) and at telomeres (telomere position effect) and are also involved in the segregation ...

  16. Electrotransfer of Plasmid Vector DNA into Muscle

    Science.gov (United States)

    Miyazaki, Satsuki; Miyazaki, Jun-Ichi

    Wolff et al. (1990) first reported that plasmid DNA injected into skeletal muscle is taken up by muscle cells and the genes in the plasmid are expressed for more than two months thereafter, although the transfected DNA does not usually undergo chromosomal integration (Wolff et al., 1991, 1992). However, the relatively low expression levels attained by this method have hampered its applications for uses other than as a DNA vaccine (Davis et al., 1995). There are a number of reports analyzing the conditions that affect the efficiency of gene transfer by intramuscular DNA injection and assessing the fine structures of expression plasmid vectors that may affect expression levels (Davis et al., 1993; Liang et al., 1996; Norman et al., 1997). Furthermore, various attempts were done to improve the efficiency of gene transfer by intramus cular DNA injection. Consequently, regenerating muscle was shown to produce 80-fold or more protein than did normal muscle, following injection of an expression plas-mid. Muscle regeneration was induced by treatment with cardiotoxin or bupivacaine (Wells, 1993; Vitadello et al., 1994). We previously demonstrated that by combining a strong promoter and bupivacaine pretreatment intramuscular injection of an IL-5 expression plasmid results in IL-5 production in muscle at a level sufficient to induce marked proliferation of eosinophils in the bone marrow and eosinophil infiltration of various organs (Tokui et al., 1997). It was also reported that a single intramuscular injection of an erythropoietin expression plasmid produced physiologically significant elevations in serum erythropoietin levels and increased hematocrits in adult mice (Tripathy et al., 1996). Hematocrits in these animals remained elevated at >60% for at least 90 days after a single injection. However, improvements to this method have not been sufficient to extend its applications including clinical use.

  17. Plasmid Copy Number Determination by Quantitative Polymerase Chain Reaction.

    Science.gov (United States)

    Anindyajati; Artarini, A Anita; Riani, Catur; Retnoningrum, Debbie S

    2016-01-01

    Recombinant therapeutic proteins are biopharmaceutical products that develop rapidly for years. Recombinant protein production in certain hosts requires vector expression harboring the gene encoding the corresponding protein. Escherichia coli is the prokaryote organism mostly used in recombinant protein production, commonly using a plasmid as the expression vector. Recombinant protein production is affected by plasmid copy number harboring the encoded gene, hence the determination of plasmid copy number also plays an important role in establishing a recombinant protein production system. On the industrial scale, a low copy number of plasmids are more suitable due to their better stability. In the previous study we constructed pCAD, a plasmid derived from the low copy number pBR322 plasmid. This study was aimed to confirm pCAD's copy number by quantitative polymerase chain reaction (qPCR). Plasmid copy number was determined by comparing the quantification signal from the plasmid to those from the chromosome. Copy number was then calculated by using a known copy number plasmid as a standard. Two pairs of primers, called tdk and ori, were designed for targeting a single gene tdk in the chromosome and a conserved domain in the plasmid's ori, respectively. Primer quality was analyzed in silico using PrimerSelect DNASTAR and PraTo software prior to in vitro evaluation on primer specificity and efficiency as well as optimization of qPCR conditions. Plasmid copy number determination was conducted on E. coli lysates harboring each plasmid, with the number of cells ranging from 10(2)-10(5) cells/μL. Cells were lysed by incubation at 95ºC for 10 minutes, followed by immediate freezing at -4°C. pBR322 plasmid with the copy number of ~19 copies/cell was used as the standard, while pJExpress414-sod plasmid possessing the high copy number pUC ori was also determined to test the method being used. In silico analysis based on primer-primer and primer-template interactions showed

  18. Engineering Escherichia coli to increase plasmid DNA production in high cell-density cultivations in batch mode

    Directory of Open Access Journals (Sweden)

    Borja Gheorghe M

    2012-09-01

    Full Text Available Abstract Background Plasmid DNA (pDNA is a promising molecule for therapeutic applications. pDNA is produced by Escherichia coli in high cell-density cultivations (HCDC using fed-batch mode. The typical limitations of such cultivations, including metabolic deviations like aerobic acetate production due to the existence of substrate gradients in large-scale bioreactors, remain as serious challenges for fast and effective pDNA production. We have previously demonstrated that the substitution of the phosphotransferase system by the over-expressed galactose permease for glucose uptake in E. coli (strain VH33 allows efficient growth, while strongly decreases acetate production. In the present work, additional genetic modifications were made to VH33 to further improve pDNA production. Several genes were deleted from strain VH33: the recA, deoR, nupG and endA genes were inactivated independently and in combination. The performance of the mutant strains was evaluated in shake flasks for the production of a 6.1 kb plasmid bearing an antigen gene against mumps. The best producer strain was cultivated in lab-scale bioreactors using 100 g/L of glucose to achieve HCDC in batch mode. For comparison, the widely used commercial strain DH5α, carrying the same plasmid, was also cultivated under the same conditions. Results The various mutations tested had different effects on the specific growth rate, glucose uptake rate, and pDNA yields (YP/X. The triple mutant VH33 Δ (recA deoR nupG accumulated low amounts of acetate and resulted in the best YP/X (4.22 mg/g, whereas YP/X of strain VH33 only reached 1.16 mg/g. When cultivated at high glucose concentrations, the triple mutant strain produced 186 mg/L of pDNA, 40 g/L of biomass and only 2.2 g/L of acetate. In contrast, DH5α produced only 70 mg/L of pDNA and accumulated 9.5 g/L of acetate. Furthermore, the supercoiled fraction of the pDNA produced by the triple mutant was nearly constant

  19. Pathogenicity of Vibrio anguillarum serogroup O1 strains compared to plasmids, outer membrane protein profiles and siderophore production

    DEFF Research Database (Denmark)

    Pedersen, K.; Gram, Lone; Austin, D.A.;

    1997-01-01

    The virulence of 18 strains of Vibrio anguillarum serogroup 01 was compared to plasmid content, expression of siderophores and outer membrane proteins. All strains, irrespective of plasmid content, produced siderophores and inducible outer membrane proteins under iron-limited conditions. Only str...

  20. Use of FabV-Triclosan Plasmid Selection System for Efficient Expression and Production of Recombinant Proteins in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Syed A Ali

    Full Text Available Maintenance of recombinant plasmid vectors in host bacteria relies on the presence of selection antibiotics in the growth media to suppress plasmid -free segregants. However, presence of antibiotic resistance genes and antibiotics themselves is not acceptable in several applications of biotechnology. Previously, we have shown that FabV-Triclosan selection system can be used to select high and medium copy number plasmid vectors in E. coli. Here, we have extended our previous work and demonstrated that expression vectors containing FabV can be used efficiently to express heterologous recombinant proteins in similar or better amounts in E. coli host when compared with expression vectors containing β-lactamase. Use of small amount of non-antibiotic Triclosan as selection agent in growth medium, enhanced plasmid stability, applicability in various culture media, and compatibility with other selection systems for multiple plasmid maintenance are noteworthy features of FabV-Triclosan selection system.

  1. Use of FabV-Triclosan Plasmid Selection System for Efficient Expression and Production of Recombinant Proteins in Escherichia coli

    Science.gov (United States)

    Ali, Syed A.; Chew, Yik Wei; Omar, Tasyriq Che; Azman, Nizuwan

    2015-01-01

    Maintenance of recombinant plasmid vectors in host bacteria relies on the presence of selection antibiotics in the growth media to suppress plasmid -free segregants. However, presence of antibiotic resistance genes and antibiotics themselves is not acceptable in several applications of biotechnology. Previously, we have shown that FabV-Triclosan selection system can be used to select high and medium copy number plasmid vectors in E. coli. Here, we have extended our previous work and demonstrated that expression vectors containing FabV can be used efficiently to express heterologous recombinant proteins in similar or better amounts in E. coli host when compared with expression vectors containing β-lactamase. Use of small amount of non-antibiotic Triclosan as selection agent in growth medium, enhanced plasmid stability, applicability in various culture media, and compatibility with other selection systems for multiple plasmid maintenance are noteworthy features of FabV-Triclosan selection system. PMID:26642325

  2. Effect of excessive cadmium chloride on the plasmids of E. coli HB 101 in vivo

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    After Escherichia coli HB101 with plasmid pWH58, pWH98, or pTBa5 were cultered respectively in amp LB broth which contained 50 mg/L CdCl2 constantly for 24 h, these plasmids were isolated from E. coli, and the effect of excessive CdCl2 on the E. coli HB101 and plasmid DNA was studied by surveying the growth of E. coli HB101 and plasmid, argarose gel electrophoresis and analysis of restriction fragment length polymorphism (RFLP) of plasmids, and plasmid transformation. The results showed that 50 mg/L CdCl2 treatment lagged the growth of E. coli HB101 for at least 4h, but after grown for 24h there were not significant differences in the growths of E. coli HB101s and the productions of plasmids between the treatment and control. These results implified that E. coli HB101 have induced adaptability to cadmium stress and excessive CdCl2 did not inhibit the replication and amp+ gene's expression of plasmid DNA in vivo of E. coli significantly. 50 mg/L CdCl2 treatment for 24 hours might cause the sequence's change of plasmid DNA, but could not lead to the random breakage of plasmid DNA strands. Moreover, after 50 mg/L of CdCl2 treatment in vivo the transformation activities of plasmid did not altered, implied excessive CdCl2 could not affect the superhelical structure of plasmid and also not break the loop of plasmid DNA evidently.

  3. Identification of beta-exotoxin production, plasmids encoding beta-exotoxin, and a new exotoxin in Bacillus thuringiensis by using high-performance liquid chromatography.

    OpenAIRE

    Levinson, B L; Kasyan, K J; Chiu, S S; Currier, T C; González, J M

    1990-01-01

    An improved high-performance liquid chromatography separation was developed to detect and quantify beta-exotoxin production in Bacillus thuringiensis culture supernatants. Exotoxin production was assigned to a plasmid in five strains, from three subspecies (B. thuringiensis subsp. thuringiensis serotype 1, B. thuringiensis subsp. tolworthi serotype 9, and B. thuringiensis subsp. darmstadiensis serotype 10). A new exotoxin, called type II beta-exotoxin in this report, was discovered in B. thur...

  4. Increased production of aspartase in Escherichia coli K-12 by use of stabilized aspA recombinant plasmid.

    OpenAIRE

    Nishimura, N; Komatsubara, S; Kisumi, M

    1987-01-01

    Recombinant plasmid pYT471, which consists of the aspartase gene (aspA) and the multicopy vector pBR322, was lost from cells of Escherichia coli K-12 at high frequencies in medium in which aspartase was abundantly formed due to release from catabolite repression. This plasmid loss was not completely prevented by the selective pressure of antibiotic addition. To increase the stability of the aspA plasmid, pNK101 (pBR322::aspA-par) was constructed by using the partition locus (par) derived from...

  5. Characterization of the chromosomal integration of Saccharopolyspora plasmid pCM32 and its application to improve production of spinosyn in Saccharopolyspora spinosa.

    Science.gov (United States)

    Chen, Jian; Xia, Haiyang; Dang, Fujun; Xu, Qingyu; Li, Wenjun; Qin, Zhongjun

    2015-12-01

    Saccharopolyspora spinosa produces tetra-cyclic macrolide spinosyns, a group of highly efficient pesticidal agents. However, this species lacks efficient vectors for genetic manipulation. In this study, the circular plasmid pCM32 was newly isolated from Saccharopolyspora endophytica YIM 61095. The complete nucleotide sequence of pCM32 consists of 14,611 bp and is predicted to encode 17 open reading frames (ORFs). Interestingly, a putative int gene in pCM32 was predicted by homologous alignment to encode an integrase belonging to the tyrosine family of integrases/recombinases. Plasmid pCM238 containing this int locus derived from pCM32 could be transferred by conjugation from Escherichia coli into Sa. spinosa at a high frequency. Integration of pCM238 in the host chromosome was demonstrated as site-specific recombination (at the tRNA (Ser) gene) via a 56-bp core sequence within the attP/attB sites. Plasmid pCM265, a shuttle vector containing the int and attP sequences of pCM32, was constructed to introduce foreign genes into Sa. spinosa. The production of spinosad approximately doubled in Sa. spinosa NRRL18395 after introducing pCM265-derived plasmids carrying the genes for phosphofructokinase (PFK) or anthranilate synthase. These results indicate that plasmid pCM32 is an actinomycete integrative and conjugative element (AICE) and that its derived integrative vectors are useful for efficiently introducing foreign DNA into Sa. spinosa. PMID:26260388

  6. Does Labor Diversity Affect Firm Productivity?

    DEFF Research Database (Denmark)

    Parrotta, Pierpaolo; Pozzoli, Dario; Pytlikova, Mariola

    Using an employer-employee dataset, we analyze how diversity in cultural background, skills and demographic characteristics a?ects total factor productivity (TFP) of ?rms in Denmark. Implementing structural estimation of ?rms' production function, we ?nd evidence that labor diversity in skills/education...... and integration costs connected to a more demographically and culturally diverse workforce, counteract the positive e?ects of diversity on ?rm TFP, coming from creativity and knowledge spillovers. However, we ?nd that ethnic diversity is valuable for ?rms operating in industries characterized by above...

  7. Farmer's attitudes affect piglet production parameters

    OpenAIRE

    Kauppinen, T.; Valros, A.; Vesala, K.M.

    2010-01-01

    Our results show that farmers' attitudes count: treating the animals humanely, investing in a favourable environment, and having a positive attitude towards new information and scientific research is associated with an above-average productivity on piglet farms. These attitudes, when implemented and concretized in practice, also benefit the animals through a higher standard of welfare.

  8. Effects of a recombinant gene expression on ColE1-like plasmid segregation in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Ivanov Ivan

    2011-03-01

    Full Text Available Abstract Background Segregation of expression plasmids leads to loss of recombinant DNA from transformed bacterial cells due to the irregular distribution of plasmids between the daughter cells during cell division. Under non-selective conditions this segregational instability results in a heterogeneous population of cells, where the non-productive plasmid-free cells overgrow the plasmid-bearing cells thus decreasing the yield of recombinant protein. Amongst the factors affecting segregational plasmid instability are: the plasmid design, plasmid copy-number, host cell genotype, fermentation conditions etc. This study aims to investigate the influence of transcription and translation on the segregation of recombinant plasmids designed for constitutive gene expression in Escherichia coli LE392 at glucose-limited continuous cultivation. To this end a series of pBR322-based plasmids carrying a synthetic human interferon-gamma (hIFNγ gene placed under the control of different regulatory elements (promoter and ribosome-binding sites were used as a model. Results Bacterial growth and product formation kinetics of transformed E. coli LE392 cells cultivated continuously were described by a structured kinetic model proposed by Lee et al. (1985. The obtained results demonstrated that both transcription and translation efficiency strongly affected plasmid segregation. The segregation of plasmid having a deleted promoter did not exceed 5% after 190 h of cultivation. The observed high plasmid stability was not related with an increase in the plasmid copy-number. A reverse correlation between the yield of recombinant protein (as modulated by using different ribosome binding sites and segregational plasmid stability (determined by the above model was also observed. Conclusions Switching-off transcription of the hIFNγ gene has a stabilising effect on ColE1-like plasmids against segregation, which is not associated with an increase in the plasmid copy

  9. Plasmidic Expression of nemA and yafC* Increased Resistance of Ethanologenic Escherichia coli LY180 to Nonvolatile Side Products from Dilute Acid Treatment of Sugarcane Bagasse and Artificial Hydrolysate.

    Science.gov (United States)

    Shi, Aiqin; Zheng, Huabao; Yomano, Lorraine P; York, Sean W; Shanmugam, Keelnatham T; Ingram, Lonnie O

    2016-01-01

    Hydrolysate-resistant Escherichia coli SL100 was previously isolated from ethanologenic LY180 after sequential transfers in AM1 medium containing a dilute acid hydrolysate of sugarcane bagasse and was used as a source of resistance genes. Many genes that affect tolerance to furfural, the most abundant inhibitor, have been described previously. To identify genes associated with inhibitors other than furfural, plasmid clones were selected in an artificial hydrolysate that had been treated with a vacuum to remove furfural. Two new resistance genes were discovered from Sau3A1 libraries of SL100 genomic DNA: nemA (N-ethylmaleimide reductase) and a putative regulatory gene containing a mutation in the coding region, yafC*. The presence of these mutations in SL100 was confirmed by sequencing. A single mutation was found in the upstream regulatory region of nemR (nemRA operon) in SL100. This mutation increased nemA activity 20-fold over that of the parent organism (LY180) in AM1 medium without hydrolysate and increased nemA mRNA levels >200-fold. Addition of hydrolysates induced nemA expression (mRNA and activity), in agreement with transcriptional control. NemA activity was stable in cell extracts (9 h, 37°C), eliminating a role for proteinase in regulation. LY180 with a plasmid expressing nemA or yafC* was more resistant to a vacuum-treated sugarcane bagasse hydrolysate and to a vacuum-treated artificial hydrolysate than LY180 with an empty-vector control. Neither gene affected furfural tolerance. The vacuum-treated hydrolysates inhibited the reduction of N-ethylmaleimide by NemA while also serving as substrates. Expression of the nemA or yafC* plasmid in LY180 doubled the rate of ethanol production from the vacuum-treated sugarcane bagasse hydrolysate. PMID:26826228

  10. Factors affecting patulin production by Penicillium expansum.

    Science.gov (United States)

    McCallum, J L; Tsao, R; Zhou, T

    2002-12-01

    Patulin, a mycotoxin produced by Penicillium spp. during fruit spoilage, is a major concern with regard to human health because exposure can result in severe acute and chronic toxicity, including carcinogenic, mutagenic, and teratogenic effects. In this study, we investigated the effects of Penicillium expansum isolate, apple cultivar, storage temperature and time, and pH on the production of patulin. Patulin was analyzed by a previously developed micellar electrokinetic capillary electrophoresis method. P. expansum isolates originating from across Ontario produced widely differing levels of patulin, ranging from 0 to >6 mg/g by dry mycelial weight. The highest patulin levels were those for isolates displaying aggressive growth (characterized by rapidly increasing acidity) accompanied by profuse mycelial development. Distinct patterns in fungal growth rates and patulin production were evident among isolates grown in McIntosh, Empire, and Mutsu ciders. Extensive fungal growth and higher patulin levels (538 to 1,822 microg/ml on day 14) in apple ciders were associated with incubation at room temperature (25 degrees C), although potentially toxic patulin levels (75 to 396 microg/ml on day 24) were also found in refrigerated ciders (4 degrees C) inoculated with P. expansum. PMID:12495013

  11. Plasmids spread very fast in heterogeneous bacterial communities.

    OpenAIRE

    Dionisio, Francisco; Matic, Ivan; Radman, Miroslav; Rodrigues, Olivia R; Taddei, François

    2002-01-01

    Conjugative plasmids can mediate gene transfer between bacterial taxa in diverse environments. The ability to donate the F-type conjugative plasmid R1 greatly varies among enteric bacteria due to the interaction of the system that represses sex-pili formations (products of finOP) of plasmids already harbored by a bacterial strain with those of the R1 plasmid. The presence of efficient donors in heterogeneous bacterial populations can accelerate plasmid transfer and can spread by several order...

  12. Uptake of plasmid deoxyribonucleic acid by Haemophilus.

    OpenAIRE

    Gromkova, R; Goodgal, S

    1981-01-01

    The uptake of circular and linear plasmid RSF0885 deoxyribonucleic acids, (DNAs) obtained from Haemophilus parainfluenzae 14, in both homologous and heterologous recipients was studied and compared with that of chromosomal DNA. High concentrations of divalent cations stimulated the uptake of either circular or linear plasmid DNA in H. parainfluenzae 14 competent cells but did not affect the uptake of chromosomal DNA. The biological activity of linear plasmid DNA was similar to that of circula...

  13. Requirements for the formation of plasmid-transducing particles of Bacillus subtilis bacteriophage SPP1.

    OpenAIRE

    Alonso, J.C.; Lüder, G; Trautner, T A

    1986-01-01

    We had previously proposed that the production of concatemeric plasmid DNA in plasmid-transducing SPP1 particles is a consequence of phage-directed rolling-circle-type replication of plasmid DNA. The production of such DNA was greatly enhanced when DNA/DNA homology was provided between phage and plasmid DNAs (facilitation of transduction). Here we present evidence that synthesis of concatemeric plasmid DNA can proceed after phage infection under conditions non-permissive for plasmid replicati...

  14. Behavioral factors affecting exposure potential for household cleaning products.

    Science.gov (United States)

    Kovacs, D C; Small, M J; Davidson, C I; Fischhoff, B

    1997-01-01

    Behavioral experiments were performed on 342 subjects to determine whether behavior, which could affect the level of personal exposure, is exhibited in response to odors and labels which are commonly used for household chemicals. Potential for exposure was assessed by having subjects perform cleaning tasks presented as a product preference test, and noting the amount of cleaning product used, the time taken to complete the cleaning task, the product preference, and the exhibition of avoidance behavior. Product odor was found to affect product preference in the study with the pleasant odored product being preferred to the neutral and unpleasant products. Product odor was also found to influence the amount of product used; less of the odored products was used compared to the neutral product. The experiment also found that very few of the subjects in the study read the product labels, precluding analysis of the effect of such labels on product use. A postexperiment questionnaire on household cleaning product purchasing and use was administered to participants. The results indicate that significant gender differences exist. Women in the sample reported more frequent purchase and use of cleaning products resulting in an estimated potential exposure 40% greater than for the men in the sample. This finding is somewhat countered by the fact that women more frequently reported exposure avoidance behavior, such as using gloves. Additional significant gender differences were found in the stated importance of product qualities, such as odor and environmental quality. This study suggests the need for further research, in a more realistic use setting, on the impact of public education, labels, and product odor on preference, use, and exposure for different types of consumer products. PMID:9306234

  15. Production of Fibronectin Binding Protein A at the surface of Lactococcus lactis increases plasmid transfer in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Daniela Pontes

    Full Text Available Lactococci are noninvasive lactic acid bacteria frequently used as protein delivery vectors and, more recently, as DNA delivery vehicles. We previously showed that Lactococcus lactis (LL expressing the Fibronectin-Binding Protein A of Staphylococcus aureus (LL-FnBPA+ showed higher internalization rates in vitro in Caco-2 cells than the native (wt lactococci and were able to deliver a eukaryotic Green Fluorescent Protein (GFP expression plasmid in 1% of human Caco-2 cells. Here, using the bovine beta-lactoglobulin (BLG, one of the major cow's milk allergen, and GFP we characterized the potential of LL-FnBPA+ as an in vivo DNA vaccine delivery vehicle. We first showed that the invasive strain LL-FnBPA+ carrying the plasmid pValac:BLG (LL-FnBPA+ BLG was more invasive than LL-BLG and showed the same invasivity as LL-FnBPA+. Then we demonstrated that the Caco-2 cells, co-incubated with LL-FnBPA+ BLG produced up to 30 times more BLG than the Caco-2 cells co-incubated with the non invasive LL-BLG. Using two different gene reporters, BLG and GFP, and two different methods of detection, EIA and fluorescence microscopy, we showed in vivo that: i in order to be effective, LL-FnBPA+ required a pre-coating with Fetal Calf Serum before oral administration; ii plasmid transfer occurred in enterocytes without regard to the strains used (invasive or not; iii the use of LL-FnBPA+ increased the number of mice producing BLG, but not the level of BLG produced. We thus confirmed the good potential of invasive recombinant lactic acid bacteria as DNA delivery vector in vivo.

  16. Yeast 2-microns plasmid DNA replication in vitro: purification of the CDC8 gene product by complementation assay.

    OpenAIRE

    Arendes, J; Kim, K. C.; Sugino, A

    1983-01-01

    Extracts of the yeast Saccharomyces cerevisiae support DNA replication on exogenous yeast 2-microns plasmid DNA templates. A crude extract from a S. cerevisiae cell division cycle mutant, cdc8-1, expressed the temperature-sensitive phenotype since it could be inactivated at 42 degrees C in vitro. This heat-inactivated extract was fully complemented by the addition of either wild-type or cdc8-1 single-stranded DNA binding protein (SSB). restoration by SSB of the activity of the mutant cell ext...

  17. Inhibition on the production of collagen type Ⅰ, Ⅲ of activated hepatic stellate cells by antisense TIMP-1 recombinant plasmid

    Institute of Scientific and Technical Information of China (English)

    Wen-Bin Liu; Chang-Qing Yang; Wei Jiang; Yi-Qing Wang; Jing-Sheng Guo; Bo-Ming He; Ji-Yao Wang

    2003-01-01

    AIM: To investigate the inhibition effects on the productionof collagen type I, Ⅲ secreted by activated rat hepatic stellatecells (rHSCs) by antisense tissue inhibitors of metalloproteinase1 (TIMP-1) recombinant plasmid through elevating interstitialcollagenase activity.METHODS: rHSCs were extracted from normal rat liverby pronase and collagenase digestion and purified bycentrifugal elutriation, and were cultured on plastic dishesuntil they were activated to a myofibroblastic phenotypeafter 7-10 days. RT-Nest-PCR and gene recombinanttechniques were used to construct the rat antisense TIMP-1 recombinant plasmids which can express in eucaryoticcells. The recombinant plasmid and the pcDNA3 emptyplasmid were transfected in rHSCs by Effectene (QIAGEN)separately. Cells were selected after growing in DMEMcontaining 400 μg/ml G418 for 2-3 weeks. Expression ofexogenous gene was assessed by Northern blot, andexpression oflIMP-1 in rHSCs was determined by Northernblot and Western blot. We tested the interstitial collagenaseactivity with FITC-labled type I collagen as substrate.Ultimately, we quantified the type Ⅰ, Ⅲ collagen byWestern blot.RESULTS: The exogenous antisense TIMP-1 recombinantplasmid could be expressed in rHSCs well, which couldblock the expression of TIMP-1 greatly, the ratio of TIMP-1/GAPDH was 0.67, 2.41, and 2.97 separately at mRNAlevel (P<0.05); the ratio of TIMP-1/β-actin was 0.31, 0.98and 1.32 separately at protein level (P<0.05); It mightelevate active and latent interstitial collagenase activity,the collagenase activity was 0.3049, 0.1411 and 0.1196respectively. (P<0.05), which led to promotion thedegradation of type Ⅰ, Ⅲ collagen, the ratio of collagen I/β-actin was 0.63, 1.78 and 1.92 separately (P<0.05); andthe ratio of collagen Ⅲ/β-actin was 0.59, 1.81 and 1.98separately (P<0.05).CONCLUSION: These data shows that the antisense TIMP-1 recombinant plasmid has the inhibitory effects on theproduction of type Ⅰ, Ⅲ collagens

  18. Plasmid maintenance and protein overproduction in selective recycle bioreactors.

    Science.gov (United States)

    Ogden, K L; Davis, R H

    1991-02-20

    A new plasmid construct has been used in conjunction with selective recycle to successfully maintain otherwise unstable plasmid-bearing E. coli cells in a continuous bioreactor and to produce significant amounts of the plasmid-encoded protein beta-lactamase. The plasmid is constructed so that pilin expression, which leads to bacterial flocculation, is under control of the tac operon. The plasmid-bearing cells are induced to flocculate in the separator, whereas cell growth and product synthesis occur in the main fermentation vessel without the inhibiting effects of pilin production. Selective recycle allows for the maintenance of the plasmid-bearing cells by separating flocculent, plasmid-bearing cells from nonflocculent, segregant cells in an inclined settler, and recycling only the plasmid-bearing cells to the reactor. As a result, product expression levels are maintained that are more than ten times the level achieved without selective recycle. All experimental data agree well with theoretical predictions. PMID:18597374

  19. The 2 micron plasmid purloins the yeast cohesin complex

    OpenAIRE

    Mehta, Shwetal; Yang, Xian Mei; Chan, Clarence S.; Dobson, Melanie J.; Jayaram, Makkuni; Velmurugan, Soundarapandian

    2002-01-01

    The yeast 2 micron plasmid achieves high fidelity segregation by coupling its partitioning pathway to that of the chromosomes. Mutations affecting distinct steps of chromosome segregation cause the plasmid to missegregate in tandem with the chromosomes. In the absence of the plasmid stability system, consisting of the Rep1 and Rep2 proteins and the STB DNA, plasmid and chromosome segregations are uncoupled. The Rep proteins, acting in concert, recruit the yeast cohesin complex to the STB locu...

  20. The influence of sensory product properties on affective and symbolic product experience

    OpenAIRE

    Fenko, A.; Schifferstein, H.N.J.

    2012-01-01

    Creating pleasurable products requires understanding of the influence of sensory product properties on affective user experience and symbolic meaning of products. This paper gives an overview of a series of studies, in which we investigated the impact of sensory product properties (color, material, sound, smell, and taste) on affective user experiences (pleasure, annoyance, satisfaction, and surprise) and symbolic meanings of products (freshness, warmth, and noisiness). The results demonstrat...

  1. Relations between affective music and speech: Evidence from dynamics of affective piano performance and speech production

    Directory of Open Access Journals (Sweden)

    Xiaoluan eLiu

    2015-07-01

    Full Text Available This study compares affective piano performance with speech production from the perspective of dynamics: unlike previous research, this study uses finger force and articulatory effort as indexes reflecting the dynamics of affective piano performance and speech production respectively. Moreover, for the first time physical constraints such as piano fingerings and speech articulatory distance are included due to their potential contribution to different patterns of dynamics. A piano performance experiment and speech production experiment were conducted in four emotions: anger, fear, happiness and sadness. The results show that in both piano performance and speech production, anger and happiness generally have high dynamics while sadness has the lowest dynamics, with fear in the middle. Fingerings interact with fear in the piano experiment and articulatory distance interacts with anger in the speech experiment, i.e., large physical constraints produce significantly higher dynamics than small physical constraints in piano performance under the condition of fear and in speech production under the condition of anger. Using production experiments, this study firstly supports previous perception studies on relations between affective music and speech. Moreover, this is the first study to show quantitative evidence for the importance of considering motor aspects such as dynamics in comparing music performance and speech production in which motor mechanisms play a crucial role.

  2. Product Meaning, Affective Use Evaluation, and Transfer: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Sacha Helfenstein

    2005-01-01

    Full Text Available The first part of this investigation explored the multidimensional nature of product meaning, referring to the variety of connotations and functions a consumer associates with a particular product category. The subsequent experiment examined the moderation effects of product meaning and other attributes of the user on (a the affective evaluation of an obstructed use interaction, and (b the transfer of emotion between devices presented as being either of the same or a different brand. Although the failure experience essentially caused frustration, this reaction varied substantially among consumers depending on product meaning, age, and gender. The results also showed that the emotion dimensions of pleasure, arousal, and dominance were affected in distinct ways, and that, in addition to the consumer variables, transfer was mainly dependent on the brand relation. Nevertheless, user frustration did not cause general brand aversion, indicating that poor designs do not unconditionally threaten the customer relationship.

  3. Key weather extremes affecting potato production in The Netherlands

    NARCIS (Netherlands)

    Oort, van P.A.J.; Timmermans, B.G.H.; Meinke, H.B.; Ittersum, van M.K.

    2012-01-01

    The possible impact of climate change on frequency and severity of weather extremes is hotly debated among climate scientists. Weather extremes can have a significant impact on agricultural production, but their effect is often unclear; this due to interaction with other factors that affect yield an

  4. Key weather extremes affecting potato production in The Netherlands

    NARCIS (Netherlands)

    Oort, van P.A.J.; Timmermans, B.G.H.

    2012-01-01

    This dataset contains the underlying data for the study: Van Oort, P. A. J., B. G. H. Timmermans, H. Meinke, and M. K. Van Ittersum. "Key weather extremes affecting potato production in The Netherlands." European Journal of Agronomy 37, no. 1 (2012): 11-22. http://dx.doi.org/10.1016/j.eja.2011.09.00

  5. The influence of sensory product properties on affective and symbolic product experience

    NARCIS (Netherlands)

    Fenko, A.; Schifferstein, H.N.J.

    2012-01-01

    Creating pleasurable products requires understanding of the influence of sensory product properties on affective user experience and symbolic meaning of products. This paper gives an overview of a series of studies, in which we investigated the impact of sensory product properties (color, material,

  6. Identification of the pXO1 plasmid in attenuated Bacillus anthracis vaccine strains.

    Science.gov (United States)

    Liang, Xudong; Zhang, Huijuan; Zhang, Enmin; Wei, Jianchun; Li, Wei; Wang, Bingxiang; Dong, Shulin; Zhu, Jin

    2016-07-01

    Anthrax toxins and capsule are the major virulence factors of Bacillus anthracis. They are encoded by genes located on the plasmids pXO1 and pXO2, respectively. The vaccine strain Pasteur II was produced from high temperature subcultures of B. anthracis, which resulted in virulence attenuation through the loss of the plasmid pXO1. However, it is unclear whether the high temperature culture completely abolishes the plasmid DNA or affects the replication of the plasmid pXO1. In this study, we tested 3 B. anthracis vaccine strains, including Pasteur II from France, Qiankefusiji II from Russia, and Rentian II from Japan, which were all generated from subcultures at high temperatures. Surprisingly, we detected the presence of pXO1 plasmid DNA using overlap PCR in all these vaccine strains. DNA sequencing analysis of overlap PCR products further confirmed the presence of pXO1. Moreover, the expression of the protective antigen (PA) encoded on pXO1 was determined by using SDS-PAGE and western blotting. In addition, we mimicked Pasteur's method and exposed the A16R vaccine strain, which lacks the pXO2 plasmid, to high temperature, and identified the pXO1 plasmid in the subcultures at high temperatures. This indicated that the high temperature treatment at 42.5°C was unable to eliminate pXO1 plasmid DNA from B. anthracis. Our results suggest that the attenuation of the Pasteur II vaccine strain is likely due to the impact of high temperature stress on plasmid replication, which in turn limits the copy number of pXO1. Our data provide new insights into the mechanisms of the remaining immunogenicity and toxicity of the vaccine strains. PMID:27029580

  7. Spread of Extended Spectrum Cephalosporinase-Producing Escherichia coli Clones and Plasmids from Parent Animals to Broilers and to Broiler Meat in a Production Without Use of Cephalosporins

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Jensen, Jacob Dyring; Hasman, Henrik;

    2014-01-01

    Objectives: This study investigated the occurrence of extended spectrum cephalosporinase (ESC)–producing Escherichia coli in a broiler production with no cephalosporin use and a low use of antimicrobials in general. Furthermore, it investigated whether the current consumption of aminopenicillins...... selects for ESC-producing E. coli and whether certain clones or plasmids spread from imported parent flocks to the meat. Materials and Methods: ESC-producing E. coli was isolated using MacConkey broth with 1 mg/L of ceftriaxone. ESC genes were identified using polymerase chain reaction and sequencing...... (not flock) level was obtained from VetStat, a database for mandatory registration of veterinary prescriptions in Denmark. Results: ESC-producing E. coli occurred in 93% (27/29) of broiler parent farms in 2011, 27% (53/197) of broiler flocks in 2010, and 3.3% (4/121) of Danish retail broiler meat in...

  8. Plasmid segregation mechanisms

    DEFF Research Database (Denmark)

    Ebersbach, Gitte; Gerdes, Kenn; Charbon, Gitte Ebersbach

    2005-01-01

    Bacterial plasmids encode partitioning (par) loci that ensure ordered plasmid segregation prior to cell division. par loci come in two types: those that encode actin-like ATPases and those that encode deviant Walker-type ATPases. ParM, the actin-like ATPase of plasmid R1, forms dynamic filaments...... that segregate plasmids paired at mid-cell to daughter cells. Like microtubules, ParM filaments exhibit dynamic instability (i.e., catastrophic decay) whose regulation is an important component of the DNA segregation process. The Walker box ParA ATPases are related to MinD and form highly dynamic, oscillating...... filaments that are required for the subcellular movement and positioning of plasmids. The role of the observed ATPase oscillation is not yet understood. However, we propose a simple model that couples plasmid segregation to ParA oscillation. The model is consistent with the observed movement...

  9. The affecting of perceived product quality and perceived risk on perceived product value

    OpenAIRE

    Pisnik Korda, Aleksandra

    2015-01-01

    Perceived value is an extremely important concept in marketing and many authors have dealt with it in the recent years. There are numerous factors affecting perceived product value and we focused on three: perceived product price, perceived product quality and perceived risk. In this paper we present two of them: perceived product quality and perceived risk. Perceived product value is the difference between value in use and price. Value in use is a mix of benefits, which a customer is likely ...

  10. Knowledge Elecitation for Factors Affecting Taskforce Productivity using a Questionnaire

    OpenAIRE

    Sohail, Muhammad; Khan, Abdur Rashid

    2009-01-01

    In this paper we present the process of Knowledge Elicitation through a structured questionnaire technique. This is an effort to depict a problem domain as Investigation of factors affecting taskforce productivity. The problem has to be solved using the expert system technology. This problem is the very first step how to acquire knowledge from the domain experts. Knowledge Elicitation is one of the difficult tasks in knowledge base formation which is a key component of expert system. The ques...

  11. SPP1-mediated plasmid transduction.

    OpenAIRE

    Canosi, U; Lüder, G; Trautner, T A

    1982-01-01

    The virulent Bacillus subtilis phage SPP1 transduces plasmid DNA. Plasmid-transducing phages contain only plasmid DNA. Such DNA represents a concatemer of monomeric plasmid molecules with the molecular weight of mature SPP1 DNA. Biological parameters of plasmid transduction are described.

  12. Plasmid DNA fermentation strategies: influence on plasmid stability and cell physiology.

    Science.gov (United States)

    Silva, Filomena; Queiroz, João A; Domingues, Fernanda C

    2012-03-01

    In order to provide sufficient pharmaceutical-grade plasmid DNA material, it is essential to gain a comprehensive knowledge of the bioprocesses involved; so, the development of protocols and techniques that allow a fast monitoring of process performance is a valuable tool for bioprocess design. Regarding plasmid DNA production, the metabolic stress of the host strain as well as plasmid stability have been identified as two of the key parameters that greatly influence plasmid DNA yields. The present work describes the impact of batch and fed-batch fermentations using different C/N ratios and different feeding profiles on cell physiology and plasmid stability, investigating the potential of these two monitoring techniques as valuable tools for bioprocess development and design. The results obtained in batch fermentations showed that plasmid copy number values suffered a pronounced increase at the end of almost all fermentation conditions tested. Regarding fed-batch fermentations, the strategies with exponential feeding profiles, in contrast with those with constant feeding, showed higher biomass and plasmid yields, the maximum values obtained for these two parameters being 95.64 OD(600) and 344.3 mg plasmid DNA (pDNA)/L, respectively, when using an exponential feed rate of 0.2 h(-1). Despite the results obtained, cell physiology and plasmid stability monitoring revealed that, although higher pDNA overall yields were obtained, this fermentation exhibited lower plasmid stability and percentage of viable cells. In conclusion, this study allowed clarifying the bioprocess performance based on cell physiology and plasmid stability assessment, allowing improvement of the overall process and not only plasmid DNA yield and cell growth. PMID:22089386

  13. Characterization of plasmid burden and copy number in Saccharomyces cerevisiae for optimization of metabolic engineering applications

    OpenAIRE

    Karim, Ashty S.; Curran, Kathleen A.; Alper, Hal S.

    2012-01-01

    Many metabolic engineering and genetic engineering applications in yeast rely on the use of plasmids. Despite their pervasive use and the diverse collections available, there is a fundamental lack of understanding of how commonly used DNA plasmids affect the cell’s ability to grow and how the choice of plasmid components can influence plasmid load and burden. In this study, we characterized the major attributes of the 2μ and centromeric plasmids typically used in yeast by examining the impact...

  14. Do ICTs Affect Workforce Productivity in Egyptian Industrial Organizations?

    Directory of Open Access Journals (Sweden)

    M. Elsaadani

    2014-06-01

    Full Text Available The present study aims to investigate the influence of Information Communication Technologies-ICTs’ dimensions (Information Technology (IT, Management Information System (MIS, Office automation (OA, Intranet and Internet on workforce productivity for a group of industrial organizations in Alexandria - Egypt. The population of the study included managers and staff members working in different areas related to ICTs in selected industrial organizations at various managerial levels. A descriptive-statistical combined research study was conducted. Simple random sampling was used for the selection of the participating industrial organization. A questionnaire was used as the data collection method. Expert comments were used to check the validity of study instrument, and the reliability of questions was calculated as 79% using Cronbach’s Alpha coefficient. Single variable t-test, Friedman and variance analysis tests were used for the analysis. Study findings revealed that the specified dimensions of ICTs positively affect workforce productivity of industrial organizations in Alexandria - Egypt.

  15. Transformation of Bacillus thuringiensis protoplasts by plasmid deoxyribonucleic acid.

    OpenAIRE

    Martin, P A; Lohr, J. R.; Dean, D H

    1981-01-01

    A method has been developed to transform plasmid deoxyribonucleic acid into protoplasts of the insect pathogen Bacillus thuringiensis. Protoplasts were formed by treatment of cells with lysozyme. The efficiency of formation of protoplasts was affected by the strain, the media, and the cell density. Deoxyribonucleic acid uptake was induced by polyethylene glycol. Deoxyribonucleic acid from the Staphylococcus aureus plasmid pC194 was used for transformation. Although this plasmid could not be i...

  16. Knowledge Elecitation for Factors Affecting Taskforce Productivity using a Questionnaire

    CERN Document Server

    Sohail, Muhammad

    2009-01-01

    In this paper we present the process of Knowledge Elicitation through a structured questionnaire technique. This is an effort to depict a problem domain as Investigation of factors affecting taskforce productivity. The problem has to be solved using the expert system technology. This problem is the very first step how to acquire knowledge from the domain experts. Knowledge Elicitation is one of the difficult tasks in knowledge base formation which is a key component of expert system. The questionnaire was distributed among 105 different domain experts of Public and Private Organizations (i.e. Education Institutions, Industries and Research etc) in Pakistan. A total 61 responses from these experts were received. All the experts were well qualified, highly experienced and has been remained the members for selection committees a number of times for different posts. Facts acquired were analyzed from which knowledge was extracted and elicited. A standard shape was given to the questionnaire for further research as...

  17. Production measurements affected by x irradiation of chicken semen

    International Nuclear Information System (INIS)

    Single Comb White Leghorn (S.C.W.L.) and Dark Cornish semen was x-irradiated with 1000 R and introduced into S.C.W.L. hens to produce S.C.W.L. and crossbred chicks. The irradiation reduced the fertilizing capacity of the semen about 25% and the hatchability of the embryos about 38%. Semen of the two breeds was affected differently since there was much less alteration of embryonic development among purebred, S.C.W.L. chicks than among Cornish-sired crossbreds. As is typical, crossbred chicks gained weight faster than purebred S.C.W.L. irrespective of radiation damage. After irradiation, live weight was 4% less at 16 weeks of age for the crossbreds but no substantial effect on growth was evident for the S.C.W.L., although they were significantly heavier at hatching in the irradiated population. The rate of egg production in the first 30 days declined 15% under pressure from the irradiation damage. The distribution, as well as the frequency, of embryonic mortalities changed after parental semen irradiation. The majority of embryonic deaths occurred during the first 6 days of incubation with a coincidental decrease in the proportion of deaths occurring late during incubation. Posthatching mortalities were not affected for S.C.W.L. but were doubled for Cornish up to 16 weeks old

  18. Factors affecting production rates of cosmogenic nuclides in extraterrestrial matter

    Science.gov (United States)

    Reedy, R. C.

    2015-10-01

    Good production rates are needed for cosmic-ray-produced nuclides to interpret their measurements. Rates depend on many factors, especially the pre-atmospheric object's size, the location of the sample in that object (such as near surface or deep inside), and the object's bulk composition. The bulk composition affects rates, especially in objects with very low and very high iron contents. Extraterrestrial materials with high iron contents usually have higher rates for making nuclides made by reactions with energetic particles and lower rates for the capture of thermal neutrons. In small objects and near the surface of objects, the cascade of secondary neutrons is being developed as primary particles are being removed. Deep in large objects, that secondary cascade is fully developed and the fluxes of primary particles are low. Recent work shows that even the shape of an object in space has a small but measureable effect. Work has been done and continues to be done on better understanding those and other factors. More good sets of measurements in meteorites with known exposure geometries in space are needed. With the use of modern Monte Carlo codes for the production and transport of particles, the nature of these effects have been and is being studied. Work needs to be done to improve the results of these calculations, especially the cross sections for making spallogenic nuclides.

  19. Crop production in salt affected soils: A biological approach

    International Nuclear Information System (INIS)

    Plant are susceptible to deleterious effects of various abiotic and biotic stresses, thus grossly affecting the growth and productivity. Amongst the abiotic stresses, soil salinity is most significant and prevalent in both developed and developing countries. As a consequences, good productive lands are being desertified at a very high pace. To combat this problem various approaches involving soil management and drainage are underway but with little success. It seems that a durable solution of the salinity and water-logging problems may take a long time and we may have to learn to live with salinity and to find other ways to utilize the affected lands fruitfully. A possible approach could be to tailor plants to suit the deleterious environment. The saline-sodic soils have excess of sodium, are impermeable, have little or no organic matter and are biologically almost dead. Introduction of a salt tolerant crop will provide a green cover and will improve the environment for biological activity, increase organic matter and will improve the soil fertility. The plant growth will result in higher carbon dioxide levels, and would thus create acidic conditions in the soil which would dissolve the insoluble calcium carbonate and will help exchange sodium with calcium ions on the soil complex. The biomass produced could be used directly as fodder or by the use of biotechnological and other procedures it could be converted into other value added products. However, in order to tailor plants to suit these deleterious environments, acquisition of better understanding of the biochemical and genetic aspects of salt tolerance at the cellular/molecular level is essential. For this purpose model systems have been carefully selected to carry out fundamental basic research that elucidates and identifies the major factors that confer salt tolerance in a living system. With the development of modern biotechnological methods it is now possible to introduce any foreign genetic material known

  20. Deficient sumoylation of yeast 2-micron plasmid proteins Rep1 and Rep2 associated with their loss from the plasmid-partitioning locus and impaired plasmid inheritance.

    Directory of Open Access Journals (Sweden)

    Jordan B Pinder

    Full Text Available The 2-micron plasmid of the budding yeast Saccharomyces cerevisiae encodes copy-number amplification and partitioning systems that enable the plasmid to persist despite conferring no advantage to its host. Plasmid partitioning requires interaction of the plasmid Rep1 and Rep2 proteins with each other and with the plasmid-partitioning locus STB. Here we demonstrate that Rep1 stability is reduced in the absence of Rep2, and that both Rep proteins are sumoylated. Lysine-to-arginine substitutions in Rep1 and Rep2 that inhibited their sumoylation perturbed plasmid inheritance without affecting Rep protein stability or two-hybrid interaction between Rep1 and Rep2. One-hybrid and chromatin immunoprecipitation assays revealed that Rep1 was required for efficient retention of Rep2 at STB and that sumoylation-deficient mutants of Rep1 and Rep2 were impaired for association with STB. The normal co-localization of both Rep proteins with the punctate nuclear plasmid foci was also lost when Rep1 was sumoylation-deficient. The correlation of Rep protein sumoylation status with plasmid-partitioning locus association suggests a theme common to eukaryotic chromosome segregation proteins, sumoylated forms of which are found enriched at centromeres, and between the yeast 2-micron plasmid and viral episomes that depend on sumoylation of their maintenance proteins for persistence in their hosts.

  1. Plasmids encoding therapeutic agents

    Science.gov (United States)

    Keener, William K.

    2007-08-07

    Plasmids encoding anti-HIV and anti-anthrax therapeutic agents are disclosed. Plasmid pWKK-500 encodes a fusion protein containing DP178 as a targeting moiety, the ricin A chain, an HIV protease cleavable linker, and a truncated ricin B chain. N-terminal extensions of the fusion protein include the maltose binding protein and a Factor Xa protease site. C-terminal extensions include a hydrophobic linker, an L domain motif peptide, a KDEL ER retention signal, another Factor Xa protease site, an out-of-frame buforin II coding sequence, the lacZ.alpha. peptide, and a polyhistidine tag. More than twenty derivatives of plasmid pWKK-500 are described. Plasmids pWKK-700 and pWKK-800 are similar to pWKK-500 wherein the DP178-encoding sequence is substituted by RANTES- and SDF-1-encoding sequences, respectively. Plasmid pWKK-900 is similar to pWKK-500 wherein the HIV protease cleavable linker is substituted by a lethal factor (LF) peptide-cleavable linker.

  2. Knowledge of Repetitions Range Affects Force Production in Trained Females

    Directory of Open Access Journals (Sweden)

    Israel Halperin, Saied J. Aboodarda, Fabien A. Basset, David G. Behm

    2014-12-01

    Full Text Available Most studies have examined pacing strategies with cyclical activities (running and cycling. It has been demonstrated that males employ different pacing strategies during repeated maximal voluntary contractions (MVCs dependent upon a known endpoint. Since different fatiguing mechanisms have been identified between the genders, it is not known if females use comparable pacing strategies. The purpose of this study was to examine if informing female subjects regarding the number of MVCs to perform would affect force and electromyography (EMG. Twenty well-trained females completed 3 fatiguing protocols in a randomized order. In the control condition participants were informed they would perform twelve MVCs and then actually completed twelve. In the unknown condition they were not told how many MVCs to perform but were stopped after twelve. In the deception condition they were initially informed to perform 6 MVCs, but after the 6th MVC they were asked to perform a few more MVCs and were stopped after twelve. During the first 6 MVCs, forces in the deception condition were greater compared to the unknown (p = 0.021, ES = 0.65, 5% and control (p = 0.022, ES = 0.42, 3% conditions. No differences were found between conditions in the last 6 MVCs. A main effect for repetitions showed force deficits during the first 6 MVCs (p = 0.000, ES = 1.81, 13% and last 6 MVCs (p = 0.05, ES = 0.34, 3%. No differences were found between conditions in biceps and triceps EMG. However, EMG decreased during the first 6 MVCs for biceps (p = 0.001, ES = 1.0, 14% and triceps (p = 0.001, ES = 0.76, 14% across conditions. No differences were found in the last 6 MVCs. The anticipation of performing fewer MVCs led to increased force, whereas no endpoint led to decreased force production.

  3. Toxin plasmids of Clostridium perfringens.

    Science.gov (United States)

    Li, Jihong; Adams, Vicki; Bannam, Trudi L; Miyamoto, Kazuaki; Garcia, Jorge P; Uzal, Francisco A; Rood, Julian I; McClane, Bruce A

    2013-06-01

    In both humans and animals, Clostridium perfringens is an important cause of histotoxic infections and diseases originating in the intestines, such as enteritis and enterotoxemia. The virulence of this Gram-positive, anaerobic bacterium is heavily dependent upon its prolific toxin-producing ability. Many of the ∼16 toxins produced by C. perfringens are encoded by large plasmids that range in size from ∼45 kb to ∼140 kb. These plasmid-encoded toxins are often closely associated with mobile elements. A C. perfringens strain can carry up to three different toxin plasmids, with a single plasmid carrying up to three distinct toxin genes. Molecular Koch's postulate analyses have established the importance of several plasmid-encoded toxins when C. perfringens disease strains cause enteritis or enterotoxemias. Many toxin plasmids are closely related, suggesting a common evolutionary origin. In particular, most toxin plasmids and some antibiotic resistance plasmids of C. perfringens share an ∼35-kb region containing a Tn916-related conjugation locus named tcp (transfer of clostridial plasmids). This tcp locus can mediate highly efficient conjugative transfer of these toxin or resistance plasmids. For example, conjugative transfer of a toxin plasmid from an infecting strain to C. perfringens normal intestinal flora strains may help to amplify and prolong an infection. Therefore, the presence of toxin genes on conjugative plasmids, particularly in association with insertion sequences that may mobilize these toxin genes, likely provides C. perfringens with considerable virulence plasticity and adaptability when it causes diseases originating in the gastrointestinal tract. PMID:23699255

  4. Factors affecting research productivity of production and operations management groups: An empirical study

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available This paper identifies factors that promote research productivity of production and operations management (POM groups of researchers in US business schools. In this study, research productivity of a POM group is defined as the number of articles published per POM professor in a specific period of time. The paper also examines factors that affect research quality, as measured by the number of articles published per POM professor in journals, which have been recognized in the POM literature as an elite set. The results show that three factors increase both the research productivity and the quality of the articles published by professors of a POM group. These factors are (a the presence of a POM research center, (b funding received from external sources for research purposes, and (c better library facilities. Doctoral students do assist in improving research quality and productivity, but they are not the driving force. These results have important implications for establishing policy guidelines for business schools. For example, real-world problems are funded by external sources and have a higher probability of publication. Furthermore, schools could place more emphasis on external funding, as most engineering schools do, since groups receiving external funding are more productive in terms of research.

  5. Logistic Analysis of Factors Affecting the Productivity of Peanut Farms

    OpenAIRE

    Topcu, Yavuz

    2009-01-01

    Due to low domestic production, the domestic peanut demand cannot be met and therefore, foreign trade always gives deficit in favor of import. Peanut is an important raw material for food industry, and Turkey has potential to increase her peanut production capacity. However, up to now, neglecting this production unit and not taking required incentives and guidance for producers have created current problems. To explore these problems, the effects of ecologic and topographic structures of Osma...

  6. A Content Analysis of Factors Affecting New Product Development Process

    OpenAIRE

    Eda Atilgan-Inan; Aslihan Buyukkupcu; Serkan Akinci

    2010-01-01

    The objective of this study is to review the international marketing literature on new product development process and compare the changes in the important factors in the process with the changes in the management approaches. For this purpose, the articles in three international marketing journals were selected and “new product development” and “new product performance” were searched for in the abstracts. After grouping the variables in the process, they were compared with the perspectives of...

  7. Statistical Frequency in Perception Affects Children’s Lexical Production

    Science.gov (United States)

    Richtsmeier, Peter T.; Gerken, LouAnn; Goffman, Lisa; Hogan, Tiffany

    2009-01-01

    Children’s early word production is influenced by the statistical frequency of speech sounds and combinations. Three experiments asked whether this production effect can be explained by a perceptual learning mechanism that is sensitive to word-token frequency and/or variability. Four-year-olds were exposed to nonwords that were either frequent (presented 10 times) or infrequent (presented once). When the frequent nonwords were spoken by the same talker, children showed no significant effect of perceptual frequency on production. When the frequent nonwords were spoken by different talkers, children produced them with fewer errors and shorter latencies. The results implicate token variability in perceptual learning. PMID:19338981

  8. Statistical frequency in perception affects children's lexical production.

    Science.gov (United States)

    Richtsmeier, Peter T; Gerken, LouAnn; Goffman, Lisa; Hogan, Tiffany

    2009-06-01

    Children's early word production is influenced by the statistical frequency of speech sounds and combinations. Three experiments asked whether this production effect can be explained by a perceptual learning mechanism that is sensitive to word-token frequency and/or variability. Four-year-olds were exposed to nonwords that were either frequent (presented 10 times) or infrequent (presented once). When the frequent nonwords were spoken by the same talker, children showed no significant effect of perceptual frequency on production. When the frequent nonwords were spoken by different talkers, children produced them with fewer errors and shorter latencies. The results implicate token variability in perceptual learning. PMID:19338981

  9. Purification of large plasmids with methacrylate monolithic columns.

    Science.gov (United States)

    Krajnc, Nika Lendero; Smrekar, Franci; Cerne, Jasmina; Raspor, Peter; Modic, Martina; Krgovic, Danijela; Strancar, Ales; Podgornik, Ales

    2009-08-01

    The rapid evolution of gene therapy and DNA vaccines results in an increasing interest in producing large quantities of pharmaceutical grade plasmid DNA. Most current clinical trials involve plasmids of 10 kb or smaller in size, however, future requirements for multigene vectors including extensive control regions may require the production of larger plasmids, e. g., 20 kb and bigger. The objective of this study was to examine certain process conditions for purification of large plasmids with the size of up to 93 kb. Since there is a lack of knowledge about production and purification of bigger plasmid DNA, cell lysis and storage conditions were investigated. The impact of chromatographic system and methacrylate monolithic column on the degradation of plasmid molecules under nonbinding conditions at different flow rates was studied. Furthermore, capacity measurements varying salt concentration in loading buffer were performed and the capacities up to 13 mg of plasmid per mL of the monolithic column were obtained. The capacity flow independence in the range from 130 to 370 cm/h was observed. Using high resolution monolithic column the separation of linear and supercoiled isoforms of large plasmids was obtained. Last but not least, since the baseline separation of RNA and pDNA was achieved, the one step purification on larger CIM DEAE 8 mL tube monolithic column was performed and the fractions were analyzed by CIM analytical monolithic columns. PMID:19598166

  10. Statistical Frequency in Perception Affects Children’s Lexical Production

    OpenAIRE

    Richtsmeier, Peter T.; Gerken, LouAnn; Goffman, Lisa; Hogan, Tiffany

    2009-01-01

    Children’s early word production is influenced by the statistical frequency of speech sounds and combinations. Three experiments asked whether this production effect can be explained by a perceptual learning mechanism that is sensitive to word-token frequency and/or variability. Four-year-olds were exposed to nonwords that were either frequent (presented 10 times) or infrequent (presented once). When the frequent nonwords were spoken by the same talker, children showed no significant effect o...

  11. How does household production affect measured income inequality?

    OpenAIRE

    Frazis, Harley; Stewart, Jay

    2009-01-01

    Although income inequality has been studied extensively, relatively little attention has been paid to the role of household production. Economic theory predicts that households with less money income will produce more goods at home. Thus extended income, which includes the value of household production, should be more equally distributed than money income. Previous studies have found this to be the case and have speculated that the more-equal distribution of extended income is due to the weak...

  12. Unique type of plasmid maintenance function: postsegregational killing of plasmid-free cells.

    OpenAIRE

    Gerdes, K; Rasmussen, P. B.; Molin, S

    1986-01-01

    The stability locus parB+ of plasmid R1 has been found to specify a unique type of plasmid maintenance function. Two genes, hok (host killing) and sok (suppressor of killing), are required for the stabilizing activity. The hok gene encodes a highly toxic gene product, whose overexpression causes a rapid killing and a concomitant dramatic change in morphology of the host cell. The other gene, sok, was found to encode a product that counteracts the hok gene-mediated killing. The parB+ region wa...

  13. Methyl salicylate production in tomato affects biotic interactions

    NARCIS (Netherlands)

    K. Ament; V. Krasikov; S. Allmann; M. Rep; F.L.W. Takken; R.C. Schuurink

    2010-01-01

    The role of methyl salicylate (MeSA) production was studied in indirect and direct defence responses of tomato (Solanum lycopersicum) to the spider mite Tetranychus urticae and the root-invading fungus Fusarium oxysporum f. sp. lycopersici, respectively. To this end, we silenced the tomato gene enco

  14. Affected functional networks associated with sentence production in classic galactosemia.

    Science.gov (United States)

    Timmers, Inge; van den Hurk, Job; Hofman, Paul Am; Zimmermann, Luc Ji; Uludağ, Kâmil; Jansma, Bernadette M; Rubio-Gozalbo, M Estela

    2015-08-01

    Patients with the inherited metabolic disorder classic galactosemia have language production impairments in several planning stages. Here, we assessed potential deviations in recruitment and connectivity across brain areas responsible for language production that may explain these deficits. We used functional magnetic resonance imaging (fMRI) to study neural activity and connectivity while participants carried out a language production task. This study included 13 adolescent patients and 13 age- and gender-matched healthy controls. Participants passively watched or actively described an animated visual scene using two conditions, varying in syntactic complexity (single words versus a sentence). Results showed that patients recruited additional and more extensive brain regions during sentence production. Both groups showed modulations with syntactic complexity in left inferior frontal gyrus (IFG), a region associated with syntactic planning, and in right insula. In addition, patients showed a modulation with syntax in left superior temporal gyrus (STG), whereas the controls did not. Further, patients showed increased activity in right STG and right supplementary motor area (SMA). The functional connectivity data showed similar patterns, with more extensive connectivity with frontal and motor regions, and restricted and weaker connectivity with superior temporal regions. Patients also showed higher baseline cerebral blood flow (CBF) in right IFG and trends towards higher CBF in bilateral STG, SMA and the insula. Taken together, the data demonstrate that language abnormalities in classic galactosemia are associated with specific changes within the language network. These changes point towards impairments related to both syntactic planning and speech motor planning in these patients. PMID:25979518

  15. A Content Analysis of Factors Affecting New Product Development Process

    Directory of Open Access Journals (Sweden)

    Eda Atilgan-Inan

    2010-07-01

    Full Text Available The objective of this study is to review the international marketing literature on new product development process and compare the changes in the important factors in the process with the changes in the management approaches. For this purpose, the articles in three international marketing journals were selected and “new product development” and “new product performance” were searched for in the abstracts. After grouping the variables in the process, they were compared with the perspectives of management in the related periods. The results indicated that organizational factors have always been important for new product development process, which is in line with the nature of the innovation process. But the emphasis on internal factors has increased in the 21st century which is congruent with the change in management perspective foregrounding resource based view. The study differs from the similar literature review studies on the point that it deals with the topic from international marketing perspective. Therefore, R&D and other marketing studies are not included in the review and the study proposes the important factors from international firms’ point of view.

  16. The FRIABLE1 gene product affects cell adhesion in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Lutz Neumetzler

    Full Text Available Cell adhesion in plants is mediated predominantly by pectins, a group of complex cell wall associated polysaccharides. An Arabidopsis mutant, friable1 (frb1, was identified through a screen of T-DNA insertion lines that exhibited defective cell adhesion. Interestingly, the frb1 plants displayed both cell and organ dissociations and also ectopic defects in organ separation. The FRB1 gene encodes a Golgi-localized, plant specific protein with only weak sequence similarities to known proteins (DUF246. Unlike other cell adhesion deficient mutants, frb1 mutants do not have reduced levels of adhesion related cell wall polymers, such as pectins. Instead, FRB1 affects the abundance of galactose- and arabinose-containing oligosaccharides in the Golgi. Furthermore, frb1 mutants displayed alteration in pectin methylesterification, cell wall associated extensins and xyloglucan microstructure. We propose that abnormal FRB1 action has pleiotropic consequences on wall architecture, affecting both the extensin and pectin matrices, with consequent changes to the biomechanical properties of the wall and middle lamella, thereby influencing cell-cell adhesion.

  17. Affecting Factors and Security System of Food Production - A Case Study of Mingshan County

    OpenAIRE

    Lin zheng; Wenxiu Zhang

    2012-01-01

    The Grey Relational Analysis of food production has been established based on the data of grain production in Mingshan County, Sichuan province, collected from 2003 to 2008. According to the Relational Grade, factors that affect the County’s input on grain production and the degree of their influence have been analyzed. The conclusion is that unit grain yield, sown area of grain, and rural labor force is important factors affecting the county’s food production. Thus many advices were proposed...

  18. Soil surface properties affected by organic by-products

    OpenAIRE

    Pachepsky Ya.A.; Rawls W.J.; Fournier L.L.; Filgueira R.R.; Sikora L.J.

    2002-01-01

    The beneficial effects of amending soils with organic by-products include improvement of both chemical and physical factors. Very few studies have investigated changes in the soil specific surface area (SSA) after amendments with manures or composts. Soil samples were taken from plots before and after four years� application of manures, composts or nitrogen fertilizer. A corn-wheat-soybean rotation was grown. Soil samples were tested for changes in water retention at �15 bar, bu...

  19. Chemical factors affecting fission product transport in BWR severe accidents

    International Nuclear Information System (INIS)

    Chemical changes may significantly alter physical properties of fission product materials, and hence their state and transport rate. Thus, it is possible that an appropriate accounting of chemical change could have a large impact on transport model results. This paper will describe how the chemical reactions of Cs, I, and Te are being implemented in the transport model that is used in the Severe Accident Sequence Analysis (SASA) Program at Oak Ridge National Laboratory (ORNL)

  20. Do Personality Traits Affect Productivity? Evidence from the Lab

    OpenAIRE

    Cubel, Maria; Nuevo-Chiquero, Ana; Sanchez-Pages, Santiago; Vidal-Fernández, Marian

    2014-01-01

    While survey data supports a strong relationship between personality and labor market outcomes, the exact mechanisms behind this association remain unexplored. In this paper, we take advantage of a controlled laboratory set-up to test whether this relationship operates through productivity, and isolate this mechanism from other channels such as bargaining ability or self-selection into jobs. Using a gender neutral real-effort task, we analyse the impact of the Big Five personality traits on p...

  1. Does thalidomide affect IL-2 response and production?

    Science.gov (United States)

    Fernandez, L P; Schlegel, P G; Baker, J; Chen, Y; Chao, N J

    1995-08-01

    The exact mechanism of immunosuppression by thalidomide is poorly understood. A common denominator in the pathogenesis of graft-vs.-host disease, graft rejection, reactional lepromatous leprosy, and autoimmune disorders modulated by thalidomide is the activation of T lymphocytes culminating in the synthesis of interleukin-2 (IL-2), the expression of high-affinity IL-2 receptors, and the induction of proliferation. We investigated the effect of thalidomide on the production of IL-2 by the human leukemia cell line Jurkat through induction of IL-2 gene enhancer activity and through the presence of IL-2 in supernatants. beta-galactosidase activity, encoded by a reporter lac z construct and controlled by a transcription factor in thalidomide-treated PMA- and ionomycin-stimulated Jurkat cells, was similar (97 +/- 1.33%; p > 0.1) to non-thalidomide-treated controls at all drug concentrations tested. IL-2 enhancer-driven beta-galactose activity of thalidomide-treated and stimulated cells was also similar to that of untreated controls (p > 0.2). The IL-2 production of activated nontransfected Jurkat cells was gauged by using the IL-2-dependent cell line HT-2 as a readout and by ELISA. Jurkat cells were subcloned by limiting dilution. Bulk cultures and three subclones (J.5.2.5., J.5.2.9., and J.5.3.8.) were assayed at 6, 12, and 24 hours after PHA/PMA-induced stimulation. No inhibitory effect on the IL-2 production by thalidomide could be detected at any of the drug concentrations tested (5-30 micrograms/mL), whereas 10 to 100 ng/mL of cyclosporine inhibited the IL-2 production by 95 to 100%. In addition, we observed neither inhibition of IL-2-dependent proliferation of HT-2 nor inhibition of PHA-induced proliferation of peripheral mononuclear cells by thalidomide at all drug concentrations used (5-30 micrograms/mL). These results do not support the possibility of a modulatory effect on the immune response by thalidomide via IL-2 production and IL-2 response. PMID:7635184

  2. cmp, a cis-acting plasmid locus that increases interaction between replication origin and initiator protein.

    OpenAIRE

    Gennaro, M L; Novick, R P

    1986-01-01

    pT181, a 4.4-kilobase multicopy plasmid of Staphylococcus aureus, encodes a trans-acting initiator protein, RepC, which was rate limiting for replication. Deletions in a 500-base-pair region of the plasmid external to the minimal replicon decreased the ability of the plasmid to compete with a coexisting incompatible plasmid. These deletions, which define a region called cmp (for competition), appeared to affect the interaction of RepC and the plasmid origin of replication. However, in the hom...

  3. Indoor Air Quality (IAQ) as a Parameter Affecting Workplace Productivity

    OpenAIRE

    Stefanovska Ceravolo, Ljubica; Mirakovski, Dejan; Polenakovik, Radmil; Ristova, Emilija; Sovreski, Zlatko

    2012-01-01

    The aim of this paper is to give a review of the effects of indoor air quality (IAQ) upon the productivity and performance within the workplace. IAQ is known to be a factor causing health issues and has been connected with sick-leave among office workers through many studies in developed countries. This is a problem which persists in developed countries, however it has not been given the attention it deserves in developing countries, considering the fact that there is a lack of information an...

  4. Impurities in mixed streams that affect specification products

    International Nuclear Information System (INIS)

    In the 1960's new markets were recognized for natural gas liquids. These new markets, butanes as a gasoline additive and propane as a potential motor fuel, brought with them the problems that high levels of contaminants, chiefly sulfur compounds and unwanted olefins, caused. This paper reports that the Clean Air Act of 1990 will require the gas processing industry to reduce the contaminants in its products. One of the early steps in this quality control program was the industry approval of HD-5 as a propane specification. The use of NGL butanes in the new Methyl Tertiary Butyl Ether (MTBE) market indicates the need for similar butane specifications. While some companies have established specifications for certain situations, the need for acceptable specifications on an industry wide basis is apparent. These should be developed under the guidance and direction of the entire gas processing industry

  5. Factors affecting future crude oil production in South East Asia

    International Nuclear Information System (INIS)

    In the face of booming regional demand, crude oil production in the South East Asian region will decline from a 1996 peak of 5.7 million barrels a day to 3.5 million barrels a day in 2005 unless major new exploration investments are undertaken. The current fiscal terms for such investment will not attract continued significant funds to the region given the low crude price outlook, tough competitive global environment for the upstream industry, and the emergence of more attractive fiscal terms in politically and commercially stable countries with proven prospectivity. There is evidence from the emerging trend toward fiscal terms softening and differentiation around risk in some countries, that the commercial reality is becoming accepted. It remains to be seen if the various national political, bureaucratic and industry constituencies guiding these decisions within the region can respond decisively to mitigate the growing crude import dependency. (author). 2 tabs

  6. In Silico Detection and Typing of Plasmids using PlasmidFinder and Plasmid Multilocus Sequence Typing

    DEFF Research Database (Denmark)

    Carattoli, Alessandra; Zankari, Ea; García-Fernández, Aurora; Larsen, Mette Voldby; Lund, Ole; Villa, Laura; Aarestrup, Frank Møller; Hasman, Henrik

    2014-01-01

    genomes of multidrug-resistant Enterobacteriaceae species by the rapid detection of known plasmid types. Replicon sequences from 559 fully sequenced plasmids associated with the family Enterobacteriaceae in the NCBI nucleotide database were collected to build a consensus database for integration into a...... plasmid sequence types (STs) and new alleles and ST variants. In conclusion, testing of the two Web tools using both fully assembled plasmid sequences and WGS-generated draft genomes showed them to be able to detect a broad variety of plasmids that are often associated with antimicrobial resistance in......In the work presented here, we designed and developed two easy-to-use Web tools for in silico detection and characterization of whole-genome sequence (WGS) and whole-plasmid sequence data from members of the family Enterobacteriaceae. These tools will facilitate bacterial typing based on draft...

  7. OVARIAN HORMONE PRODUCTION AFFECTED BY AMYGDALIN ADDITION IN VITRO

    Directory of Open Access Journals (Sweden)

    Marek Halenár

    2015-02-01

    Full Text Available Amygdalin, a natural substance, is a cyanogenic glycoside occurring in the seeds of apricots and bitter almonds. It is a controversial anti-tumor compound that has been used as an alternative cancer drug for many years. Amygdalin is composed of two molecules of glucose, one of benzaldehyde, which induces an analgesic action, and one of hydrocyanic acid, which is an anti-neoplastic compound. This in vitro study was performed to evaluate the possible impact of amygdalin (1, 10, 100, 1000, 10 000 μg/mL on the secretory activity of granulosa cells (GCs from porcine cyclic ovaries. The release of progesterone and estradiol-17β by GCs were evaluated by ELISA. In our study, the noticeable changes in estradiol-17β release by ovarian GCs were determined after the amygdalin addition. Amygdalin, at the highest dose (10 000 μg/mL, significantly (P≤0.05 stimulated the release of estradiol-17β by GCs, in comparison to the untreated control cells. On the contrary, no significant (P≥0.05 changes in the progesterone release by GCs caused by amygdalin addition were observed. In conclusion, obtained results showed that the amygdalin application (various doses to ovarian GCs caused a dose-dependent stimulation of the estradiol-17β release, but not progesterone, and its possible modulatory impact on the steroid production in porcine ovaries.

  8. Does concrete composition affect photoneutron production inside radiation therapy bunkers?

    International Nuclear Information System (INIS)

    Different types of concretes are used for bunker construction for radiation therapy. As neutron production occurs in high-energy photon beams, the purpose of this study was to investigate the effect of different concretes on photoneutron doses at an isocenter and maze entrance door. The 18-MV photon beam of a Varian 2100 C/D linear accelerator and a radiation therapy bunker were simulated using the MCNPX Monte Carlo code. Different commercially available concretes were used in photoneutron calculations for the simulated bunker. Higher neutron doses of the water phantom were seen for barytes and galena concretes, while there was no significant (less than 1%) difference between the neutron dose of the phantom for all other concretes. Also, the neutron fluence at the inner and outer maze entrance varied up to 36% depending on the concretes' atomic compositions. It can be concluded that application of high-density concretes in order to use limited space or for other purposes may cause higher neutron doses in the maze entrance door and consequently may impose stricter requirements for neutron shielding of maze entrance doors. (author)

  9. Conjugative plasmids of Neisseria gonorrhoeae.

    Directory of Open Access Journals (Sweden)

    Emilia Pachulec

    Full Text Available Many clinical isolates of the human pathogen Neisseria gonorrhoeae contain conjugative plasmids. The host range of these plasmids is limited to Neisseria species, but presence of a tetracycline (tetM determinant inserted in several of these plasmids is an important cause of the rapid spread of tetracycline resistance. Previously plasmids with different backbones (Dutch and American type backbones and with and without different tetM determinants (Dutch and American type tetM determinants have been identified. Within the isolates tested, all plasmids with American or Dutch type tetM determinants contained a Dutch type plasmid backbone. This demonstrated that tetM determinants should not be used to differentiate between conjugal plasmid backbones. The nucleotide sequences of conjugative plasmids with Dutch type plasmid backbones either not containing the tetM determinant (pEP5233 or containing Dutch (pEP5289 or American (pEP5050 type tetM determinants were determined. Analysis of the backbone sequences showed that they belong to a novel IncP1 subfamily divergent from the IncP1alpha, beta, gamma, delta and epsilon subfamilies. The tetM determinants were inserted in a genetic load region found in all these plasmids. Insertion was accompanied by the insertion of a gene with an unknown function, and rearrangement of a toxin/antitoxin gene cluster. The genetic load region contains two toxin/antitoxins of the Zeta/Epsilon toxin/antitoxin family previously only found in Gram positive organisms and the virulence associated protein D of the VapD/VapX toxin/antitoxin family. Remarkably, presence of VapX of pJD1, a small cryptic neisserial plasmid, in the acceptor strain strongly increased the conjugation efficiency, suggesting that it functions as an antitoxin for the conjugative plasmid. The presence of the toxin and antitoxin on different plasmids might explain why the host range of this IncP1 plasmid is limited to Neisseria species. The isolated plasmids

  10. Remarkable stability of an instability-prone lentiviral vector plasmid in Escherichia coli Stbl3

    OpenAIRE

    Al-Allaf, Faisal A.; Tolmachov, Oleg E.; Zambetti, Lia Paola; Tchetchelnitski, Viktoria; Mehmet, Huseyin

    2012-01-01

    Large-scale production of plasmid DNA to prepare therapeutic gene vectors or DNA-based vaccines requires a suitable bacterial host, which can stably maintain the plasmid DNA during industrial cultivation. Plasmid loss during bacterial cell divisions and structural changes in the plasmid DNA can dramatically reduce the yield of the desired recombinant plasmid DNA. While generating an HIV-based gene vector containing a bicistronic expression cassette 5′-Olig2cDNA-IRES-dsRed2-3′, we encountered ...

  11. The interplay between relatedness and horizontal gene transfer drives the evolution of plasmid-carried public goods.

    OpenAIRE

    Mc Ginty S.É.; Lehmann L.; Brown S.P.; Rankin D.J.

    2013-01-01

    Plasmids carry a wide range of genes that are often involved in bacterial social behaviour. The question of why such genes are frequently mobile has received increasing attention. Here, we use an explicit population genetic approach to model the evolution of plasmid-borne bacterial public goods production. Our findings highlight the importance of both transmission and relatedness as factors driving the evolution of plasmid-borne public goods production. We partition the effects of plasmid tra...

  12. Genetic analysis of agrocin 84 production and immunity in Agrobacterium spp.

    OpenAIRE

    Ryder, M H; Slota, J.E.; Scarim, A; Farrand, S K

    1987-01-01

    Mutations affecting agrocin production on the 48-kilobase (kb) plasmid, pAgK84, can be complemented in trans with cloned portions of the plasmid. Five complementation groups ranging in minimum size from 1.2 to 5.6 kb were identified within a 14-kb segment. Plasmid pAgK84-encoded immunity to agrocin 84 was located to two separate regions of the plasmid. Either region alone was sufficient to protect sensitive strains, and both loci mapped to the agrocin 84 biosynthesis region. One region is loc...

  13. Plasmid acquisition in microgravity

    Science.gov (United States)

    Juergensmeyer, Margaret A.; Juergensmeyer, Elizabeth A.; Guikema, James A.

    1995-01-01

    In microgravity, bacteria often show an increased resistance to antibiotics. Bacteria can develop resistance to an antibiotic after transformation, the acquisition of DNA, usually in the form of a plasmid containing a gene for resistance to one or more antibiotics. In order to study the capacity of bacteria to become resistant to antibiotics in microgravity, we have modified the standard protocol for transformation of Escherichia coli for use in the NASA-flight-certified hardware package, The Fluid Processing Apparatus (FPA). Here we report on the ability of E. coli to remain competent for long periods of time at temperatures that are readily available on the Space Shuttle, and present some preliminary flight results.

  14. Evolved plasmid-host interactions reduce plasmid interference cost.

    Science.gov (United States)

    Yano, Hirokazu; Wegrzyn, Katarznya; Loftie-Eaton, Wesley; Johnson, Jenny; Deckert, Gail E; Rogers, Linda M; Konieczny, Igor; Top, Eva M

    2016-09-01

    Antibiotic selection drives adaptation of antibiotic resistance plasmids to new bacterial hosts, but the molecular mechanisms are still poorly understood. We previously showed that a broad-host-range plasmid was poorly maintained in Shewanella oneidensis, but rapidly adapted through mutations in the replication initiation gene trfA1. Here we examined if these mutations reduced the fitness cost of TrfA1, and whether this was due to changes in interaction with the host's DNA helicase DnaB. The strains expressing evolved TrfA1 variants showed a higher growth rate than those expressing ancestral TrfA1. The evolved TrfA1 variants showed a lower affinity to the helicase than ancestral TrfA1 and were no longer able to activate the helicase at the oriV without host DnaA. Moreover, persistence of the ancestral plasmid was increased upon overexpression of DnaB. Finally, the evolved TrfA1 variants generated higher plasmid copy numbers than ancestral TrfA1. The findings suggest that ancestral plasmid instability can at least partly be explained by titration of DnaB by TrfA1. Thus under antibiotic selection resistance plasmids can adapt to a novel bacterial host through partial loss of function mutations that simultaneously increase plasmid copy number and decrease unfavorably high affinity to one of the hosts' essential proteins. PMID:27121483

  15. The stb operon balances the requirements for vegetative stability and conjugative transfer of plasmid R388.

    Directory of Open Access Journals (Sweden)

    Catherine Guynet

    2011-05-01

    Full Text Available The conjugative plasmid R388 and a number of other plasmids carry an operon, stbABC, adjacent to the origin of conjugative transfer. We investigated the role of the stbA, stbB, and stbC genes. Deletion of stbA affected both conjugation and stability. It led to a 50-fold increase in R388 transfer frequency, as well as to high plasmid loss. In contrast, deletion of stbB abolished conjugation but provoked no change in plasmid stability. Deletion of stbC showed no effect, neither in conjugation nor in stability. Deletion of the entire stb operon had no effect on conjugation, which remained as in the wild-type plasmid, but led to a plasmid loss phenotype similar to that of the R388ΔstbA mutant. We concluded that StbA is required for plasmid stability and that StbA and StbB control conjugation. We next observed the intracellular positioning of R388 DNA molecules and showed that they localize as discrete foci evenly distributed in live Escherichia coli cells. Plasmid instability of the R388ΔΔstbA mutant correlated with aberrant localization of the plasmid DNA molecules as clusters, either at one cell pole, at both poles, or at the cell center. In contrast, plasmid molecules in the R388ΔΔstbB mutant were mostly excluded from the cell poles. Thus, results indicate that defects in both plasmid maintenance and transfer are a consequence of variations in the intracellular positioning of plasmid DNA. We propose that StbA and StbB constitute an atypical plasmid stabilization system that reconciles two modes of plasmid R388 physiology: a maintenance mode (replication and segregation and a propagation mode (conjugation. The consequences of this novel concept in plasmid physiology will be discussed.

  16. Plasmid-Chromosome Recombination of Irradiated Shuttle Vector DNA in African Green Monkey Kidney Cells.

    Science.gov (United States)

    Mudgett, John Stuart

    1987-09-01

    An autonomously replicating shuttle vector was used to investigate the enhancement of plasmid-chromosome recombination in mammalian host cells by ultraviolet light and gamma radiation. Sequences homologous to the shuttle vector were stably inserted into the genome of African Green Monkey kidney cells to act as the target substrate for these recombination events. The SV40- and pBR322-derived plasmid DNA was irradiated with various doses of radiation before transfection into the transformed mammalian host cells. The successful homologous transfer of the bacterial ampicillin resistance (amp^{rm r}) gene from the inserted sequences to replace a mutant amp^->=ne on the shuttle vector was identified by plasmid extraction and transformation into E. coli host cells. Ultraviolet light (UV) was found not to induce homologous plasmid-chromosome recombination, while gamma radiation increased the frequency of recombinant plasmids detected. The introduction of specific double -strand breaks in the plasmid or prolonging the time of plasmid residence in the mammalian host cells also enhanced plasmid-chromosome recombination. In contrast, plasmid mutagenesis was found to be increased by plasmid UV irradiation, but not to change with time. Plasmid survival, recombination, and mutagenesis were not affected by treating the mammalian host cells with UV light prior to plasmid transfection. The amp^{rm r} recombinant plasmid molecules analyzed were found to be mostly the result of nonconservative exchanges which appeared to involve both homologous and possibly nonhomologous interactions with the host chromosome. The observation that these recombinant structures were obtained from all of the plasmid alterations investigated suggests a common mechanistic origin for plasmid -chromosome recombination in these mammalian cells.

  17. Extraction of Dengue 2 Plasmid DNA Vaccine (pD2) from Cell Lysates by Aqueous Two-Phase Systems

    OpenAIRE

    Keila Aparecida Moreira; Adilson Castro Chaves; Ernesto Torres Marques; Duarte Miguel Ferreira Prazeres; Walter Mendes de Azevedo; Ana Lucia Figueiredo Porto; Jose Luiz de Lima Filho

    2007-01-01

    This research describes the partitioning in PEG/phosphate systems of the plasmid pD2, a dengue 2 plasmid DNA vaccine, present in a clarified E. coli alkaline lysate. Factors that affect the partition as PEG molecular weight, plasmid concentration and the lysate volume loaded in the system were investigated. Results showed that partition behavior of plasmid DNA depends on the system molecular weight, a considerable amount of protein of the cell lysate was accumulated in the interphase of the s...

  18. Investigation of plasmid-induced growth defect in Pseudomonas putida.

    Science.gov (United States)

    Mi, Jia; Sydow, Anne; Schempp, Florence; Becher, Daniela; Schewe, Hendrik; Schrader, Jens; Buchhaupt, Markus

    2016-08-10

    Genetic engineering in bacteria mainly relies on the use of plasmids. But despite their pervasive use for physiological studies as well as for the design and optimization of industrially used production strains, only limited information about plasmid induced growth defects is available for different replicons and organisms. Here, we present the identification and characterization of such a phenomenon for Pseudomonas putida transformants carrying the pBBR1-derived plasmid pMiS1. We identified the kanamycin resistance gene and the transcription factor encoding rhaR gene to be causal for the growth defect in P. putida. In contrast, this effect was not observed in Escherichia coli. The plasmid-induced growth defect was eliminated after introduction of a mutation in the plasmid-encoded rep gene, thus enabling construction of the non-toxic variant pMiS4. GFP reporters construct analyses and qPCR experiments revealed a distinctly lowered plasmid copy number for pMiS4, which is probably the reason for alleviation of the growth defect by this mutation. Our work expands the knowledge about plasmid-induced growth defects and provides a useful low-copy pBBR1 replicon variant. PMID:27287537

  19. Factors affecting Small-Scale Coffee Production in Githunguri District, Kenya

    OpenAIRE

    Margaret Njeri Gathura

    2013-01-01

    This study was carried out to determine the factors affecting small scale coffee production in Kenya. The establishments under study were small-scale coffee farms in Githunguri District.It was to determine whether marketing factors, finances, government policies and physical and human resources affect coffee production in Githunguri District. Primary sources included use of questionnaires, observation and interviews. Secondary sources included desk research, library research on journals, text...

  20. Conjugation is necessary for a bacterial plasmid to survive under protozoan predation.

    Science.gov (United States)

    Cairns, Johannes; Jalasvuori, Matti; Ojala, Ville; Brockhurst, Michael; Hiltunen, Teppo

    2016-02-01

    Horizontal gene transfer by conjugative plasmids plays a critical role in the evolution of antibiotic resistance. Interactions between bacteria and other organisms can affect the persistence and spread of conjugative plasmids. Here we show that protozoan predation increased the persistence and spread of the antibiotic resistance plasmid RP4 in populations of the opportunist bacterial pathogen Serratia marcescens. A conjugation-defective mutant plasmid was unable to survive under predation, suggesting that conjugative transfer is required for plasmid persistence under the realistic condition of predation. These results indicate that multi-trophic interactions can affect the maintenance of conjugative plasmids with implications for bacterial evolution and the spread of antibiotic resistance genes. PMID:26843557

  1. Introduction of temperature-sensitive helper and donor plasmids into Bac-to-Bac baculovirus expression systems

    Institute of Scientific and Technical Information of China (English)

    Zhihong; Huang; Ao; Li; Mengjia; Pan; Wenbi; Wu; Meijin; Yuan; Kai; Yang

    2015-01-01

    In the baculovirus shuttle vector(bacmid) system, a helper plasmid and a donor plasmid are employed to insert heterologous genes into a cloned baculovirus genome via Tn7 transposition in Escherichia coli. The helper and donor plasmids are usually cotransfected with constructed bacmids into insect cells, which will lead to integration of these plasmids into the viral genome,and hence to the production of defective virions. In this study, to facilitate the preparation of plasmid-free recombinant bacmids, we modified a set of helper and donor plasmids by replacing their replication origins with that of a temperature-sensitive(ts) plasmid, p SIM6. Using the resulting ts helper plasmid p MON7124 ts and the ts donor plasmid p FB1ts-PH-GFP, a recombinant bacmid,b Ac WT-PG(-), was constructed, and the transposition efficiency was found to be 33.1%. The plasmids were then removed by culturing at 37 °C. For b Ac WT-PG(-), the infectious progeny virus titer and the protein expression level under the control of the polyhedrin promoter were similar to those of a bacmid constructed with unmodified helper and donor plasmids. These ts plasmids will be useful for obtaining plasmid-free bacmids for both heterologous protein production and fundamental studies of baculovirus biology.

  2. Use of locked nucleic acid oligonucleotides to add functionality to plasmid DNA

    OpenAIRE

    Hertoghs, Kirsten M. L.; Ellis, Jonathan H.; Catchpole, Ian R.

    2003-01-01

    The available reagents for the attachment of functional moieties to plasmid DNA are limiting. Most reagents bind plasmid DNA in a non-sequence- specific manner, with undefined stoichiometry, and affect DNA charge and delivery properties or involve chemical modifications that abolish gene expression. The design and ability of oligonucleotides (ODNs) containing locked nucleic acids (LNAs) to bind supercoiled, double-stranded plasmid DNA in a sequence-specific manner are described for the first ...

  3. Construction and Identification of Plasmid pTA-TUB2

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    An about 1.40 Kb target gene fragment was yielded by PCR amplification with the plasmid pRB 129,which was identified by restriction enzyme digestion that the PCR product was TU B2 gene.The gene was digested by the restriction enzyme and was linked with pTA plasmid to construct pTA-TU B2 plasmid.The plasmid was transformed into Chaetomium spp.by PEG method and the transformation rate was 27/(2×105) and it is nine times higher than that of pRB 129.The transformants can grow on the PDA containing 1 000 μg*mL-1 carbendazim,which is 1 000 times higher than the original Chaetomium spp.The resistance was stable after 10 times transfer on non-selective medium.

  4. A comparison of the growth responses following intramuscular GHRH plasmid administration versus daily growth hormone injections in young pigs

    Science.gov (United States)

    The efficacy of daily porcine growth hormone (GH) injections versus plasmid-driven porcine GH-releasing hormone (pGHRH) production to promote growth was assessed. Ten-day-old piglets were injected intramuscularly with 0.1, 1, or 3 mg pGHRH, or a control plasmid followed by electroporation. Plasmid c...

  5. The Product-Agnosia Effect: How More Visual Impressions Affect Product Distinctiveness in Comparative Choice

    OpenAIRE

    Jayson Shi Jia; Baba Shiv; Sanjay Rao

    2014-01-01

    Consumer choice is often based on the relative visual appeal of competing products. Lay intuition, common marketing practice, and extant literature all suggest that more visual impressions help consumers distinguish products. This research shows that the opposite can occur. Rather than highlighting differences, seeing more pictures of products being compared can obfuscate perceptions, reduce distinctiveness and attractiveness of products, and increase choice uncertainty. Six experiments demon...

  6. Plasmid-free T7-based Escherichia coli expression systems.

    Science.gov (United States)

    Striedner, Gerald; Pfaffenzeller, Irene; Markus, Luchner; Nemecek, Sabine; Grabherr, Reingard; Bayer, Karl

    2010-03-01

    In order to release host cells from plasmid-mediated increases in metabolic load and high gene dosages, we developed a plasmid-free, T7-based E. coli expression system in which the target gene is site-specifically integrated into the genome of the host. With this system, plasmid-loss, a source of instability for conventional expression systems, was eliminated. At the same time, system leakiness, a challenging problem with recombinant systems, was minimized. The efficiency of the T7 RNA polymerase compensates for low gene dosage and provides high rates of recombinant gene expression without fatal consequences to host metabolism. Relative to conventional pET systems, this system permits improved process stability and increases the host cell's capacity for recombinant gene expression, resulting in higher product yields. The stability of the plasmid-free system was proven in chemostat cultivation for 40 generations in a non-induced and for 10 generations in a fully induced state. For this reason plasmid-free systems benefit the development of continuous production processes with E. coli. However, time and effort of the more complex cloning procedure have to be considered in relation to the advantages of plasmid-free systems in upstream-processing. PMID:19891007

  7. Plasmid-mediated transformation in Bacillus megaterium.

    OpenAIRE

    Brown, B. J.; Carlton, B C

    1980-01-01

    A transformation system was developed for Bacillus megaterium by using antibiotic resistance plasmid deoxyribonucleic acid molecules derived from Staphylococcus aureus and Bacillus cereus. Lysozyme-generated protoplasts of B. megaterium allowed uptake of plasmid deoxyribonucleic acid in the presence of polyethylene glycol. Transformants expressed the antibiotic resistance determinants present on the plasmid deoxyribonucleic acid, and reisolated plasmid deoxyribonucleic acid yielded restrictio...

  8. Factors affecting industrial wood, material production yield in Turkey’s natural beech forests

    Directory of Open Access Journals (Sweden)

    Atilla Atik

    2014-07-01

    Full Text Available The objectives of the present study are to determine the most important factors affecting industrial wood material production yield in natural oriental beech forests in Turkey using a multifaceted approach and to help entrepreneurs consider these factors to develop more sensitive and realistic production plans. In Günye Forest Management in Bartın province of the West Black Sea Region of Turkey, 41 production units were chosen as the study area. The 1277 ha study area was included in the 2007 and 2010 production management plan. The general state of the stand, natural stand structure, and production methods and tools are the factors thought most strongly affect industrial wood material production yield; 26 variables representing these factors were evaluated in the study. Through multidimensional statistical analyses, including main components, factor and regression  analysis, we found that the most important factors affecting production yield were fertility, aspect of land, skidding method, stand structure, skidding distance, growing stock, transportation and harmful abiotic factors. Production units were divided into three groups based on yield rates and the 26 variables, using discriminate analysis. From the results of the study, a sample model can be developed to help forest managers predict and plan annual industrial wood production more sensitively and realistically.

  9. Induced mutagenesis of plasmids and chromosomal genes inserted into plasmid DNA 1. Mutagenic effects of irradiations

    International Nuclear Information System (INIS)

    Effect of two physical agents: UV- and γ-radiation has been considered in comparison. DNA of RSF2124 plasmid, determining colcine synthesis and ampicillin resistance, was used as a model. Mutagenous effect is taken into account according to the appearance of Col--mutants, which are not capable of colicine synthesis. Lethal effect is determined according to ampicillin marker inactivation. After reisolation of plasmid DNA from mutant transformant, new traits and antibiotic resistance are preserved during subsequent transformations and reseedings of transformed colonies, which proves mutational nature of the transformations. Under short-wave UV irradiation (lambda=254 nm) of RSF2124 DNA a clear mutagenous effect is detected: relative amount of Col--mutants at the optimum for mutagenesis doses increased by a factor of 10. Under conditions of W-reactivation (additional UV-irradiation of recipient cells of wild C600 type) of lethal injuries an increase in mutagenous effect was observed, which is reliable for 95%. A distinct increase in mutagenesis (approximately by a factor of 4) is observed during UV-irradiation in small doses of only one recipient cell (a so-called indirect UV-mutagenesis). Thus, according to its ability to W- and indirect UV-mutagenesis plasmid DNA behaves as DNA of moderate phages, which can testify to their evolution relationship. Treatment of plasmid DNA with acridine orange before UV-irradiation protected only from lethal injuries. γ-irradiation of 60Co at inactivation approximately 10-2 increased by an order the yield of Col--mutants. The presence of the plasmid in a cell did not affect its UV-resistance

  10. Ranking factors affecting the productivity of human resources using MADM techniques

    Directory of Open Access Journals (Sweden)

    G. A. Shekari

    2012-12-01

    Full Text Available For improving and efficient uses of various resources such as labor, capital, materials, energy and information, productivity is the purpose of all economic and industrial organizations and service enterprises. The human factor is the main strategic resource and the realization axis of productivity for each type of organization. Therefore the factors affecting the productivity, depends on suitable conditions for labor. This study is performed to identification and prioritization the factors affecting the productivity of human resources in Khorasan Razavi Gas Company. The objective of this research is an applied and the data collection methods and conclusions are descriptive - survey. Statistical sample size by using Cochran's formula is considered equal to 120. To perform this study with the Delphi method, we identify the factors affecting the productivity of human resources in Khorasan Razavi Gas Company and by using MADM techniques, prioritization of these factors has been done. Also Team Expert Choice2000 software have used for analysis. Research results show that factors affecting the productivity of human resources in Khorasan Razavi Gas Company in order of importance are: Health aspects, leadership style, motivational factors, organizational commitment, work experience, general and applied education, demographic characteristics, physical environment within the organization, external environment and competitive spirit.

  11. ASSESMENT OF FACTORS AFFECTING THE PRODUCTIVITY OF AMBER CHARKHA AND ERGONOMIC EVALUATION OF WORKERS

    Directory of Open Access Journals (Sweden)

    G. V. THAKRE

    2011-11-01

    Full Text Available Increasing demands of the cotton fabrics, now a day has made it necessary to increase the production of cotton fabrics. To increase the production it is necessary to study the factors affecting the performance of the women workers working on Amber charkha. Most of the Amber charkha in rural areas are hand operated (i.e. they runwith the help of human energy input. There are various medical, technical and environmental factors which affect the productivity of women workers working on Amber charkha. This paper discusses some of those factors which are responsible for this. The various factors that are affecting the productivity are health factors,sitting posture, working environment, raw material properties, and man machine system. Each of these factors plays an important role in the overall performance of the women workers. Analysis is carried out by comparing the actual readings with the standard norms available in the literature. The detailed project work is carried out to study the different factors affecting the productivity of Amber charkha. The basic necessity of this study is to provide comfortable sitting arrangement and good working environment which would help the workers for achieving better productivity with work satisfaction.

  12. The stb operon balances the requirements for vegetative stability and conjugative transfer of plasmid R388

    OpenAIRE

    Catherine Guynet; Ana Cuevas; Gabriel Moncalián; Fernando de la Cruz

    2011-01-01

    The conjugative plasmid R388 and a number of other plasmids carry an operon, stbABC, adjacent to the origin of conjugative transfer. We investigated the role of the stbA, stbB, and stbC genes. Deletion of stbA affected both conjugation and stability. It led to a 50-fold increase in R388 transfer frequency, as well as to high plasmid loss. In contrast, deletion of stbB abolished conjugation but provoked no change in plasmid stability. Deletion of stbC showed no effect, neither in conjugation n...

  13. Plasmid vector with temperature-controlled gene expression

    International Nuclear Information System (INIS)

    In plasmid pBR327, a fragment 169 b.p. long including promotor p3 of the bla gene has been deleted. The deletional derivative so obtained (pSP2) has been used to construct a recombinant plasmid bearing a fragment of phage λ DNA with the p/sub R/ promotor and the gene of the temperature-sensitive repressor cI. It has been shown that the plasmid vector so constructed (pCE119) with promotor cR performs repressor-cI-controlled transcription of the bla gene, as a result of which induction for an hour at 420C leads to an almost 100-fold increase in the amount of product of the bla gene as compared with that at 320C. The possibility of the use of plasmid cPE119 for the expression of other genes has been demonstrated for the case of the semisynthetic β-galactosidase gene of E. coli. In this case, on induction of the cells with recombinant plasmid pCEZ12 for 3 hours at 420C, a 300-fold increase in the amount of active β-galactosidase, as compared with that at 320C, was observed. It is important to point out that under these conditions (at 420C), at least 99% of the cells containing the plasmid retain the phenotype lacZ+, which indicates the stability of the proposed vector system

  14. Physical characterization of plasmids determining synthesis of a microcin which inhibits methionine synthesis in Escherichia coli.

    OpenAIRE

    Perez-Diaz, J C; Clowes, R C

    1980-01-01

    Plasmid deoxyribonucleic acid (DNA) isolated from each of three antibiotic-resistant clinical strains of Escherichia coli producing the same microcin showed multiple bands upon agarose gel electrophoresis. Transformants selected either for microcin resistance or ampicillin resistance yielded plasmid DNA corresponding in size to only one of the multiple bands. Plasmids, isolated from all three hosts, which determined microcin resistance and microcin production measured about 4 megadaltons by s...

  15. Plasmid transfer between strains of Bacillus thuringiensis infecting Galleria mellonella and Spodoptera littoralis.

    OpenAIRE

    Jarrett, P.; Stephenson, M

    1990-01-01

    To determine the possibility of plasmid transfer occurring between strains of Bacillus thuringiensis in infected lepidopterous larvae, Galleria mellonella and Spodoptera littoralis were infected with two or more strains of B. thuringiensis and the resulting bacteria from the dead insects were examined for plasmid transfer. Transfer rates of plasmids coding for crystal production and tetracycline resistance were high, reaching levels similar to those obtained in laboratory broth cultures. Tran...

  16. A guided search genetic algorithm using mined rules for optimal affective product design

    Science.gov (United States)

    Fung, Chris K. Y.; Kwong, C. K.; Chan, Kit Yan; Jiang, H.

    2014-08-01

    Affective design is an important aspect of new product development, especially for consumer products, to achieve a competitive edge in the marketplace. It can help companies to develop new products that can better satisfy the emotional needs of customers. However, product designers usually encounter difficulties in determining the optimal settings of the design attributes for affective design. In this article, a novel guided search genetic algorithm (GA) approach is proposed to determine the optimal design attribute settings for affective design. The optimization model formulated based on the proposed approach applied constraints and guided search operators, which were formulated based on mined rules, to guide the GA search and to achieve desirable solutions. A case study on the affective design of mobile phones was conducted to illustrate the proposed approach and validate its effectiveness. Validation tests were conducted, and the results show that the guided search GA approach outperforms the GA approach without the guided search strategy in terms of GA convergence and computational time. In addition, the guided search optimization model is capable of improving GA to generate good solutions for affective design.

  17. [Localization of denitrification genes in plasmid DNA of bacteria Azospirillum brasilense].

    Science.gov (United States)

    Petrova, L P; Varshalomidze, O É; Shelud'ko, A V; Katsy, E I

    2010-07-01

    In 85-Mda plasmid (p85) of plant-associated bacteria Azospirillum brasilense Sp245 model strain, the genes encoding copper-containing nitrite reductase (nirK); heterodimeric NO-reductase (norCB); NorQ and NorD proteins affecting synthesis and (or) activation of NirK and (or) NO-reductase (norQD); catalytic subunit I ofcytochrom c oxidase (CccoN); presumable NO sensor carrying two hemeerythrine domains (orf181); and an enzyme required for synthesis of presumable NO antagonist, homocystein (metC) were identified. In the same region of p85, orf293 encoding transcriptional regulator of LysR type, orf208 whose protein product carries a formylmethanofuran dehydrogenase subunit E domain, and an orf164-encoding conservative secretory protein with unknown function were also found. Localization of a set of denitrification genes in the plasmid DNA A. brasilense Sp245 adjacent to IS elements ISAzba1 and ISAzba2 indicates potential mobility of these genes and high probability of their horizontal transfer among populations of rhizospheric bacteria. A site homologous to p85 nirK-orf208-orf181 genes was detected in the 115 kb plasmid of A. brasilense Sp7 type strain. PMID:20795494

  18. Interactions between octopine and nopaline plasmids in Agrobacterium tumefaciens.

    OpenAIRE

    Hooykaas, P J; Den Dulk-Ras, H; Ooms, G.; Schilperoort, R.A.

    1980-01-01

    Transfer of octopine Ti plasmids to strains already carrying an octopine Ti plasmid was found to occur at the same (high) frequency as transfer to Ti plasmid lacking recipients, showing that resident Ti plasmids do not exhibit entry exclusion towards incoming Ti plasmids. The resident octopine Ti plasmid was lost by the recipient after the entrance of the incoming Ti plasmid, which is indicative of the incompatibility between the Ti plasmids. Octopine Ti plasmids were found to become establis...

  19. Market Research: How Different Product Attributes Affect Consumers’ Buying Decision of Medium- haul Flights

    OpenAIRE

    Kalaja, Anna-Emilia

    2015-01-01

    This thesis is a market research of consumers’ buying behaviour. The scope is to find out how distinct product attributes affect consumers’ buying decision when purchasing a flight for a European destination. Flight as a product is a more complex than described in the thesis. The study is outlined further so that the focus in the buying process is on the evaluation of alternatives. The objective of the research is to gain up to date information about consumers’ buying behaviour, how different...

  20. Prizes and Productivity- How Winning the Fields Medal Affects Scientific Output

    OpenAIRE

    Borjas, George J.; Kirk B. Doran

    2013-01-01

    Knowledge generation is key to economic growth, and scientific prizes are designed to encourage it. But how does winning a prestigious prize affect future output? We compare the productivity of Fields medalists (winners of the top mathematics prize) to that of similarly brilliant contenders. The two groups have similar publication rates until the award year, after which the winners' productivity declines. The medalists begin to "play the field," studying unfamiliar topics at the expense of wr...

  1. Factors affecting phaeomelanin production by a melanin-producing (mel) mutant of Vibrio cholerae.

    OpenAIRE

    Ivins, B E; Holmes, R K

    1981-01-01

    In a previous study we isolated melanin-producing (mel) mutants of Vibrio cholerae and demonstrated that production of melanin during growth on solid media was stimulated by L-tyrosine and L-cysteine. In the studies reported here we analyzed factors that affected melanin production in liquid media and determined the abilities of radioactively labeled amino acids to serve as precursors for the formation of melanin by V. cholerae. Radioactivity from L-cysteine and from L-tyrosine was preferenti...

  2. Organizational climate and company productivity: the role of employee affect and employee level

    OpenAIRE

    Patterson, Malcolm; Warr, Peter; West, Michael

    2004-01-01

    Consistent with a growing number of models about affect and behaviour and with a recognition that perception alone provides no impetus for action, it was predicted that associations between company climate and productivity would be mediated by average level of job satisfaction. In a study of 42 manufacturing companies, subsequent productivity was significantly correlated in controlled analyses with eight aspects of organizational climate (e.g. skill development and concern for employee welfar...

  3. An Analysis of the Factors Affecting Dairy Cow Production in the South East of Vietnam

    OpenAIRE

    Loan, Chu Thi Kim; YOKOGAWA, hiroshi; Kawaguchi, Tsunemasa

    2005-01-01

    The paper examines the factors affecting dairy production in Ho Chi Minh and Binh Duong provinces in 2003, based on original data collected from 80 dairy farm households and 40 non-dairy forma households. Descriptive and production function analysis are the principal methods used in the study. The finding indicate that dairy farmers in the region have been faced with limited quality of veterinary and breeding services, and a lack of capital and technical knowledge. In addition, herd manageme...

  4. Effects of genes exerting growth inhibition and plasmid stability on plasmid maintenance.

    OpenAIRE

    Boe, L; Gerdes, K; Molin, S

    1987-01-01

    Plasmid stabilization mediated by the parA+ and parB+ genes of the R1 plasmid and the ccd+ and sop+ genes of the F plasmid was tested on a mini-R1 plasmid and a pBR322 plasmid derivative. The mini-R1 plasmid is thought to be unstably inherited owing to a low copy number and to random segregation of the plasmid at cell division, whereas cells harboring the pBR322 derivative used in this work are lost through competition with plasmid-free cells, mainly as a result of the shorter generation time...

  5. Metaphor priming in sentence production: concrete pictures affect abstract language production.

    Science.gov (United States)

    Sato, Manami; Schafer, Amy J; Bergen, Benjamin K

    2015-03-01

    People speak metaphorically about abstract concepts-for instance, a person can be "full of love" or "have a lot of love to give." Over the past decade, research has begun to focus on how metaphors are processed during language comprehension. Much of this work suggests that understanding a metaphorical expression involves activating brain and body systems involved in perception and motor control. However, no research to date has asked whether the same is true while speakers produce language. We address this gap using a sentence production task. Its results demonstrate that visually activating a concrete source domain can trigger the use of metaphorical language drawn from that same concrete domain, even in sentences that are thematically unrelated to the primes, a metaphorical priming effect. This effect suggests that conceptual metaphors play a part in language production. It also shows that activation in the perceptual system that is not part of an intended message can nevertheless influence sentence formulation. PMID:25443987

  6. How Planting Density Affects Number and Yield of Potato Minitubers in a Commercial Glasshouse Production System

    NARCIS (Netherlands)

    Veeken, van der A.J.H.; Lommen, W.J.M.

    2009-01-01

    Commercial potato minituber production systems aim at high tuber numbers per plant. This study investigated by which mechanisms planting density (25.0, 62.5 and 145.8 plants/m2) of in vitro derived plantlets affected minituber yield and minituber number per plantlet. Lowering planting density result

  7. 40 CFR Table 2 to Subpart Xxxx of... - Emission Limits for Tire Cord Production Affected Sources

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Emission Limits for Tire Cord Production Affected Sources 2 Table 2 to Subpart XXXX of Part 63 Protection of Environment ENVIRONMENTAL... Manufacturing Pt. 63, Subpt. XXXX, Table 2 Table 2 to Subpart XXXX of Part 63—Emission Limits for Tire...

  8. 40 CFR Table 1 to Subpart Xxxx of... - Emission Limits for Tire Production Affected Sources

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Emission Limits for Tire Production Affected Sources 1 Table 1 to Subpart XXXX of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION.... 63, Subpt. XXXX, Table 1 Table 1 to Subpart XXXX of Part 63—Emission Limits for Tire...

  9. A procedure for large-scale plasmid isolation without using ultracentrifugation.

    Science.gov (United States)

    Chakrabarti, A; Sitaric, S; Ohi, S

    1992-10-01

    An expedient procedure for large-scale plasmid isolation from Escherichia coli strains without using ultracentrifugation or special setups or reagents is described. The protocol, which utilizes a modified alkaline extraction procedure as well as differential precipitations by isopropanol and lithium chloride, is simple and rapid and yet produces plasmid DNA with a yield of about 2 mg/liter culture. The isolated plasmids consisted of mostly monomeric and dimeric covalently closed circular DNA. The plasmids could be digested by various restriction endonucleases and were compatible with gene cloning, transfection-gene expression, and viral production. PMID:1333773

  10. Construction of Recombinant Plasmid Containing S. Mutans F-ATPase β Subunit Gene

    Institute of Scientific and Technical Information of China (English)

    YU Dan-ni; JIANG Li

    2005-01-01

    objective: construct a homologous recombinant plasmid which was expected to be transformed into S. mutans Methods: a region at the 5' terminus of the S. mutans F-ATPase β subunit gene was amplified by PCR, the PCR product was inserted into vector pVA891, yielding recombinant plasmid. Results: the DNA sequence of the recombinant plasmid was identified correct in whole by restriction endonuclease and DNA sequence techniques. Conclusion: the recombinant plasmid of S. mutans DNA was cloned in effect ,it may assist in construction of homologues recombinant mutant.

  11. Low-dose plasmid DNA treatment increases plasma vasopressin and regulates blood pressure in experimental endotoxemia

    OpenAIRE

    Malardo Thiago; Batalhão Marcelo E; Panunto-Castelo Ademilson; Almeida Luciana P; Padilha Everton; Fontoura Isabela C; Silva Célio L; Carnio Evelin C; Coelho-Castelo Arlete AM

    2012-01-01

    Abstract Background Although plasmid DNA encoding an antigen from pathogens or tumor cells has been widely studied as vaccine, the use of plasmid vector (without insert) as therapeutic agent requires further investigation. Results Here, we showed that plasmid DNA (pcDNA3) at low doses inhibits the production of IL-6 and TNF-α by lipopolysaccharide (LPS)-stimulated macrophage cell line J774. These findings led us to evaluate whether plasmid DNA could act as an anti-inflammatory agent in a Wist...

  12. Vector insert-targeted integrative antisense expression system for plasmid stabilization.

    Science.gov (United States)

    Luke, Jeremy M; Carnes, Aaron E; Hodgson, Clague P; Williams, James A

    2011-01-01

    Some DNA vaccine and gene therapy vector-encoded transgenes are toxic to the E. coli plasmid production host resulting in poor production yields. For plasmid products undergoing clinical evaluation, sequence modification to eliminate toxicity is undesirable because an altered vector is a new chemical entity. We hypothesized that: (1) insert-encoded toxicity is mediated by unintended expression of a toxic insert-encoded protein from spurious bacterial promoters; and (2) that toxicity could be eliminated with antisense RNA-mediated translation inhibition. We developed the pINT PR PL vector, a chromosomally integrable RNA expression vector, and utilized it to express insert-complementary (anti-insert) RNA from a single defined site in the bacterial chromosome. Anti-insert RNA eliminated leaky fluorescent protein expression from a target plasmid. A toxic retroviral gag pol helper plasmid produced in a gag pol anti-insert strain had fourfold improved plasmid fermentation yields. Plasmid fermentation yields were also fourfold improved when a DNA vaccine plasmid containing a toxic Influenza serotype H1 hemagglutinin transgene was grown in an H1 sense strand anti-insert production strain, suggesting that in this case toxicity was mediated by an antisense alternative reading frame-encoded peptide. This anti-insert chromosomal RNA expression technology is a general approach to improve production yields with plasmid-based vectors that encode toxic transgenes, or toxic alternative frame peptides. PMID:20607625

  13. Enhancing productivity of salt affected soils through crops and cropping system

    International Nuclear Information System (INIS)

    The reclamation of salt affected soils needs the addition of soil amendment and enough water to leach down the soluble salts. The operations may also include other simple agronomic techniques to reclaim soils and to know the crops and varieties that may be grown and other management practices which may be followed on such soils (Khan, 2001). The choice of crops to be grown during reclamation of salt affected soils is very important to obtain acceptable yields. This also decides cropping systems as well as favorable diversification for early reclamation, desirable yield and to meet the other requirements of farm families. In any salt affected soils, the following three measures are adopted for reclamation and sustaining the higher productivity of reclaimed soils. 1. Suitable choice of crops, forestry and tree species; 2. Suitable choice of cropping and agroforestry system; 3. Other measures to sustain the productivity of reclaimed soils. (author)

  14. Effect of the atmospheric pressure nonequilibrium plasmas on the conformational changes of plasmid DNA

    International Nuclear Information System (INIS)

    The cold atmospheric pressure plasma, which has been widely used for biomedical applications, may potentially affect the conformation of DNA. In this letter, an atmospheric pressure plasma plume is used to investigate its effects on the conformational changes of DNA of plasmid pAHC25. It is found that the plasma plume could cause plasmid DNA topology alteration, resulting in the percentage of the supercoiled plasmid DNA form decreased while that of the open circular and linearized form of plasmid DNA increased as detected by agrose gel electrophoresis. On the other hand, further investigation by using polymerase chain reaction method shows that the atmospheric pressure plasma jet treatments under proper conditions does not affect the genes of the plasmid DNA, which may have potential application in increasing the transformation frequency by genetic engineering.

  15. Dcm methylation is detrimental to plasmid transformation in Clostridium thermocellum

    Energy Technology Data Exchange (ETDEWEB)

    Guss, Adam M [ORNL; Olson, Daniel G. [Thayer School of Engineering at Dartmouth; Caiazza, Nicky [Mascoma Corporation; Lynd, Lee R [Thayer School of Engineering at Dartmouth

    2012-01-01

    BACKGROUND: Industrial production of biofuels and other products by cellulolytic microorganisms is of interest but hindered by the nascent state of genetic tools. Although a genetic system for Clostridium thermocellum DSM1313 has recently been developed, available methods achieve relatively low efficiency and similar plasmids can transform C. thermocellum at dramatically different efficiencies. RESULTS: We report an increase in transformation efficiency of C. thermocellum for a variety of plasmids by using DNA that has been methylated by Escherichia coli Dam but not Dcm methylases. When isolated from a dam+ dcm+ E. coli strain, pAMG206 transforms C. thermocellum 100-fold better than the similar plasmid pAMG205, which contains an additional Dcm methylation site in the pyrF gene. Upon removal of Dcm methylation, transformation with pAMG206 showed a four- to seven-fold increase in efficiency; however, transformation efficiency of pAMG205 increased 500-fold. Removal of the Dcm methylation site from the pAM205 pyrF gene via silent mutation resulted in increased transformation efficiencies equivalent to that of pAMG206. Upon proper methylation, transformation efficiency of plasmids bearing the pMK3 and pB6A origins of replication increased ca. three orders of magnitude. CONCLUSION: E. coli Dcm methylation decreases transformation efficiency in C. thermocellum DSM1313. The use of properly methylated plasmid DNA should facilitate genetic manipulation of this industrially relevant bacterium.

  16. Antifungal activity of different natural dyes against traditional products affected fungal pathogens

    Institute of Scientific and Technical Information of China (English)

    R Mari selvam; AJA Ranjit Singh; K Kalirajan

    2012-01-01

    Objective: In the present study to evaluate the anti fungal activity of natural dyes against traditional products affected fungal pathogens. Methods: Many traditional craft products affected fungal pathogens were isolated using potato dextrose agar medium. The isolated fungus were identified by morphological and microscopically characterization using Alexopolus manual. 50μl of Turmeric, Terminalli, Guava and Henna natural dyes were poured into the wells of the culture plates. If antifungal activity was present on the plates, it was indicated by an inhibition zone surrounding the well containing the natural dye. Result: At a dose level of 50μl of terminalli dye was able to inhibit the growth of all the fungi tested. The absorbance rate of natural dyes analyzed by UV Spectrophotometer. The absorbance rate is high in terminalli (2.266) and turmeric (2.255). Conclusions: Natural dyes were bound with traditional products to give good colour and good antimicrobial activity against isolated fungal pathogens.

  17. Persistence of a pKPN3-Like CTX-M-15-Encoding IncFIIK Plasmid in a Klebsiella pneumonia ST17 Host during Two Years of Intestinal Colonization

    OpenAIRE

    Iren Høyland Löhr; Nils Hülter; Eva Bernhoff; Pål Jarle Johnsen; Arnfinn Sundsfjord; Umaer Naseer

    2015-01-01

    Objectives To characterize the CTX-M-15-encoding plasmid in a Klebsiella pneumoniae ST17 strain, responsible for an outbreak at a Norwegian neonatal intensive care unit and subsequent colonization of affected children for up to two years. To identify plasmid-mediated features relevant for the outbreak dynamics, and to investigate the plasmids capability of horizontal transfer, its segregational stability and plasmid-mediated fitness costs. Methods Plasmid profiling was pe...

  18. Persistence of a pKPN3-like CTX-M-15-encoding IncFIIK plasmid in a Klebsiella pneumonia ST17 host during two years of intestinal colonization

    OpenAIRE

    Löhr, Iren Høyland; Hülter, Nils Fredrik; Bernhoff, Eva; Johnsen, Pål Jarle; Sundsfjord, Arnfinn; Naseer, Mohammed Umaer

    2015-01-01

    Objectives To characterize the CTX-M-15-encoding plasmid in a Klebsiella pneumoniae ST17 strain, responsible for an outbreak at a Norwegian neonatal intensive care unit and subsequent colonization of affected children for up to two years. To identify plasmid-mediated features relevant for the outbreak dynamics, and to investigate the plasmids capability of horizontal transfer, its segregational stability and plasmid-mediated fitness costs. Methods Plasmid profiling was pe...

  19. Nucleotide sequence analysis of the lactococcal EPS plasmid pNZ4000

    NARCIS (Netherlands)

    Kranenburg, van R.; Kleerebezem, M.; Vos, de W.M.

    2000-01-01

    The complete 42180-bp nucleotide sequence of the mobilization plasmid pNZ4000, coding for exopolysaccharide (EPS) production in Lactococcus lactis, was determined. This plasmid contains a region involved in EPS biosynthesis, four functional replicons, a region containing mobilization genes, and thre

  20. Antiparallel plasmid-plasmid pairing may control P1 plasmid replication.

    OpenAIRE

    Abeles, A L; Austin, S J

    1991-01-01

    The copy number of the P1 plasmid replicon is stringently controlled, giving only one or two copies per newborn cell. Control is achieved by the action of the copy-control locus incA, which contains nine repeats of the 19-basepair binding site for the plasmid-encoded initiator protein RepA. A set of five similar repeats are present in the replication origin where RepA acts to trigger initiation. Using an in vitro replication system consisting of an Escherichia coli extract, the P1 origin as a...

  1. A plasmid in Legionella pneumophila.

    OpenAIRE

    Knudson, G B; Mikesell, P

    1980-01-01

    Sixteen strains from the six serogroups of Legionella pneumophila were examined for the presence of extrachromosomal genetic elements by a modified cleared lysate procedure, dye-buoyant centrifugation, and agarose gel electrophoresis. Two strains, Atlanta-1 and Atlanta-2 from serogroup II, each contained a plasmid of cryptic function with a molecular weight of ca. 30 megadaltons.

  2. Genetic Factors in Rhizobium Affecting the Symbiotic Carbon Costs of N2 Fixation and Host Plant Biomass Production

    DEFF Research Database (Denmark)

    Skøt, L.; Hirsch, P. R.; Witty, J. F.

    1986-01-01

    The effect of genetic factors in Rhizobium on host plant biomass production and on the carbon costs of N2 fixation in pea root nodules was studied. Nine strains of Rhizobium leguminosarum were constructed, each containing one of three symbiotic plasmids in combination with one of three different...... the lowest carbon costs of N2 fixation (7.10–8.10 μmol C/μmol N2), but shoot dry weight of those plants was also smaller than that of plants nodulated by strains with the background of B151 or JI8400. Nodules formed by these two strain types had carbon costs of N2 fixation varying between 11.26 and 13.......95 μmol C/μmol N2. The effect of symbiotic plasmids on the carbon costs was relatively small. A time-course experiment demonstrated that nodules formed by a strain derived from JI6015 were delayed in the onset of nitrogenase activity and had a lower rate of activity compared to nodules induced by a strain...

  3. Bacterial Plasmids in Antarctic Natural Microbial Assemblages

    OpenAIRE

    Kobori, Hiromi; Sullivan, Cornelius W.; Shizuya, Hiroaki

    1984-01-01

    Samples of psychrophilic and psychrotrophic bacteria were collected from sea ice, seawater, sediments, and benthic or ice-associated animals in McMurdo Sound, Antarctica. A total of 155 strains were isolated and tested for the presence of plasmids by DNA agarose gel electrophoresis. Thirty-one percent of the isolates carried at least one kind of plasmid. Bacterial isolates taken from sediments showed the highest plasmid incidence (42%), and isolates from seawater showed the lowest plasmid inc...

  4. Factors affecting Small-Scale Coffee Production in Githunguri District, Kenya

    Directory of Open Access Journals (Sweden)

    Margaret Njeri Gathura

    2013-09-01

    Full Text Available This study was carried out to determine the factors affecting small scale coffee production in Kenya. The establishments under study were small-scale coffee farms in Githunguri District.It was to determine whether marketing factors, finances, government policies and physical and human resources affect coffee production in Githunguri District. Primary sources included use of questionnaires, observation and interviews. Secondary sources included desk research, library research on journals, text books and factory publications. The target population was over 700,000 small-scale coffee producers in Kenya out of which the accessible population of 10,000 producers drawn from Githunguri District in Kiambu County was selected which a sample size of 120 respondents was sampled. Stratified sampling technique was employed to compare views among coffee producers from the various coffee societies in the area. Data analysis was both qualitative and quantitative using descriptive statistics. Data presentation was in form of tables to help interpret findings and generate conclusions that aided solutions to identified problems. The research established that marketing factors, finances, government policies and physical and human resources greatly affected coffee production. The study recommended that the government should encourage coffee production by formulating favorable marketing factors and other policies and provide finances to small scale coffee producers. Producers on the other hand should strive to provide conducive working environment to their workers so as to sustain them in their farms. This will help to improve coffee yields and quality.

  5. Does Dietary Mitigation of Enteric Methane Production Affect Rumen Function and Animal Productivity in Dairy Cows?

    Science.gov (United States)

    Veneman, Jolien B.; Muetzel, Stefan; Hart, Kenton J.; Faulkner, Catherine L.; Moorby, Jon M.; Perdok, Hink B.; Newbold, Charles J.

    2015-01-01

    It has been suggested that the rumen microbiome and rumen function might be disrupted if methane production in the rumen is decreased. Furthermore concerns have been voiced that geography and management might influence the underlying microbial population and hence the response of the rumen to mitigation strategies. Here we report the effect of the dietary additives: linseed oil and nitrate on methane emissions, rumen fermentation, and the rumen microbiome in two experiments from New Zealand (Dairy 1) and the UK (Dairy 2). Dairy 1 was a randomized block design with 18 multiparous lactating cows. Dairy 2 was a complete replicated 3 x 3 Latin Square using 6 rumen cannulated, lactating dairy cows. Treatments consisted of a control total mixed ration (TMR), supplementation with linseed oil (4% of feed DM) and supplementation with nitrate (2% of feed DM) in both experiments. Methane emissions were measured in open circuit respiration chambers and rumen samples were analyzed for rumen fermentation parameters and microbial population structure using qPCR and next generation sequencing (NGS). Supplementation with nitrate, but not linseed oil, decreased methane yield (g/kg DMI; Pmethane emissions can be significantly decreased with nitrate supplementation with only minor, but consistent, effects on the rumen microbial population and its function, with no evidence that the response to dietary additives differed due to geography and different underlying microbial populations. PMID:26509835

  6. Plasmid profile in oral Fusobacterium nucleatum from humans and Cebus apella monkeys

    Directory of Open Access Journals (Sweden)

    Paula Marcia O.

    2003-01-01

    Full Text Available Fusobacterium nucleatum is a strict anaerobe and is indigenous of the human oral cavity. This organism is commonly recovered from different monomicrobial and mixed infections in humans and animals. In this study, the plasmid profile, the plasmid stability and the penicillin-resistance association in oral F. nucleatum isolated from periodontal patients, healthy subjects and Cebus apella monkeys were evaluated. Forty-five F. nucleatum strains from patients, 38 from healthy subjects and seven from C. apella were identified and analyzed. Plasmid extraction was performed in all the isolated strains. These elements were found in 26.7% strains from patients and one strain from C. apella. Strains from healthy subjects did not show any plasmid. Most of strains showed two plasmid bands ranging from 4 to 16 Kb, but digestions with endonucleases showed that they belonged to a single plasmid. The plasmid profile was similar and stable in human and monkey strains. Also, plasmids were classified into three groups according to size. Two strains were positive to beta-lactamase production and no plasmid DNA-hybridization with a beta-lactamase gene probe was observed, suggesting a chromosomal resistance.

  7. Conjugal transfer and characterization of bacteriocin plasmids in group N (lactic acid) streptococci.

    Science.gov (United States)

    Neve, H; Geis, A; Teuber, M

    1984-01-01

    Thirteen bacteriocin-producing strains of group N (lactic acid) streptococci were screened for their potential to transfer this property by conjugation to Streptococcus lactis subsp. diacetylactis Bu2-60. Bacteriocin production in three strains was plasmid encoded as shown by conjugal transfer and by analysis of cured, bacteriocin-negative derivatives of the donor strains and the transconjugants. With Streptococcus cremoris strains 9B4 and 4G6 and S. lactis subsp. diacetylactis 6F7 as donors, bacteriocin-producing transconjugants were isolated with frequencies ranging from ca. 2 X 10(-2) to 2 X 10(-1) per recipient cell. Bacteriocin-producing transconjugants had acquired a 39.6-megadalton plasmid from the donor strains 9B4 and 4G6, and a 75-megadalton plasmid from the donor strain 6F7. As shown by restriction endonuclease analysis, the plasmids from strains 9B4 and 4G6 were almost identical. The plasmid from strain 6F7 yielded some additional fragments not present in the two other plasmids. In hybridization experiments any of the three plasmids strongly hybridized with each other and with some other bacteriocin but nontransmissible plasmids from other S. cremoris strains. Homology was also detected to a variety of cryptic plasmids in lactic acid streptococci. Images PMID:6321437

  8. Characterization of a large, stable, high-copy-number Streptomyces plasmid that requires stability and transfer functions for heterologous polyketide overproduction.

    Science.gov (United States)

    Fong, Ryan; Vroom, Jonathan A; Hu, Zhihao; Hutchinson, C Richard; Huang, Jianqiang; Cohen, Stanley N; Cohen, Stanley; Kao, Camilla M; Kao, Camilla

    2007-02-01

    A major limitation to improving small-molecule pharmaceutical production in streptomycetes is the inability of high-copy-number plasmids to tolerate large biosynthetic gene cluster inserts. A recent finding has overcome this barrier. In 2003, Hu et al. discovered a stable, high-copy-number, 81-kb plasmid that significantly elevated production of the polyketide precursor to the antibiotic erythromycin in a heterologous Streptomyces host (J. Ind. Microbiol. Biotechnol. 30:516-522, 2003). Here, we have identified mechanisms by which this SCP2*-derived plasmid achieves increased levels of metabolite production and examined how the 45-bp deletion mutation in the plasmid replication origin increased plasmid copy number. A plasmid intramycelial transfer gene, spd, and a partition gene, parAB, enhance metabolite production by increasing the stable inheritance of large plasmids containing biosynthetic genes. Additionally, high product titers required both activator (actII-ORF4) and biosynthetic genes (eryA) at high copy numbers. DNA gel shift experiments revealed that the 45-bp deletion abolished replication protein (RepI) binding to a plasmid site which, in part, supports an iteron model for plasmid replication and copy number control. Using the new information, we constructed a large high-copy-number plasmid capable of overproducing the polyketide 6-deoxyerythronolide B. However, this plasmid was unstable over multiple culture generations, suggesting that other SCP2* genes may be required for long-term, stable plasmid inheritance. PMID:17142363

  9. Preliminary Examination of Factors Affecting Manufacture of Value Added Products From Recycled Pallet Parts

    OpenAIRE

    Hosterman, Nathan Scott

    2000-01-01

    A Preliminary Examination of Factors Affecting Manufacture of Value Added Products From Recycled Pallet Parts Nathan S. Hosterman Abstract Pallets are the single largest consumer of hardwood lumber in the United States. While the pallet industry has effectively adopted widespread pallet recycling, many pallets still go into landfills with little or no value gained from their material. Recovered pallet lumber has been proposed as a potential source of material for value added woo...

  10. The effect of affect in advertising: can product preference be conditioned by background music?

    OpenAIRE

    Stone, Katrina

    2007-01-01

    The present experiment provides a recent replication of Gorn’ (1982) affective conditioning study, investigating the role of music-induced mood in advertising and its subsequent effect on product choice. As an extension to Gorn’s original procedure, the experiment has addressed certain procedural concerns and expanded the scope of the study to investigate the effect of ‘mere exposure’. This was achieved by incorporating an additional background colour variable into the procedur...

  11. Plasmid maintenance functions encoded on Dictyostelium discoideum nuclear plasmid Ddp1.

    OpenAIRE

    Hughes, J E; H. Kiyosawa; Welker, D L

    1994-01-01

    All of the plasmid-carried genes expressed during vegetative growth are essential for long-term maintenance of plasmid Ddp1 in the nucleus of Dictyostelium discoideum. Deletion of Ddp1 genes expressed only during development had no detectable effect on plasmid maintenance. Deletion of vegetatively expressed genes, either singly or in pairs, resulted in (i) a rapid loss of plasmid from cells grown in the absence of selection for plasmid retention, (ii) variation in the proportion of monomer to...

  12. Plasmid addiction systems: perspectives and applications in biotechnology

    OpenAIRE

    Kroll, Jens; Klinter, Stefan; Schneider,Cornelia; Voß, Isabella; Steinbüchel, Alexander

    2010-01-01

    Summary Biotechnical production processes often operate with plasmid‐based expression systems in well‐established prokaryotic and eukaryotic hosts such as Escherichia coli or Saccharomyces cerevisiae, respectively. Genetically engineered organisms produce important chemicals, biopolymers, biofuels and high‐value proteins like insulin. In those bioprocesses plasmids in recombinant hosts have an essential impact on productivity. Plasmid‐free cells lead to losses in the entire product recovery a...

  13. Resident enhanced repair: novel repair process action on plasmid DNA transformed into Escherichia coli K-12

    International Nuclear Information System (INIS)

    The survival of UV-irradiated DNA of plasmid NTP16 was monitored after its transformation into recipient cells containing an essentially homologous undamaged plasmid, pLV9. The presence of pLV9 resulted in a substantial increase in the fraction of damaged NTP16 molecules which survived in the recipient cells. This enhanced survival requires the host uvrA+ and uvrB+ gene products, but not the host recA+ gene product. The requirement for both homologous DNA and the uvrA+ gene products suggests that a novel repair process may act on plasmid DNA. Possible mechanisms for this process are considered

  14. Characterization of plasmids in Erwinia stewartii.

    OpenAIRE

    Coplin, D. L.; Rowan, R G; Chisholm, D A; Whitmoyer, R E

    1981-01-01

    Plasmids in 39 strains of Erwinia stewartii were examined by agarose gel electrophoresis. Most virulent strains had from 11 to 13 plasmids ranging in molecular mass from 2.8 to 210 megadaltons and contained plasmids of 210, 70, 49, 43, 29.5, 16.8, 8.8, and 2.8 megadaltons. Plasmids in strains SW2 and SS104 were characterized by both electron microscopy and agarose gel electrophoresis and may be useful as convenient references for sizing plasmids by electrophoresis. Specific size classes of pl...

  15. Quantifying and visualizing the transfer of exogenous plasmids to environmental microbial communities

    DEFF Research Database (Denmark)

    Dechesne, Arnaud

    2015-01-01

    Plasmid transfer is deemed responsible for the rapid spread of antibiotic resistance among microbes. While broad host range plasmids are known to transfer to diverse hosts in pure culture, their transfer potential to complex communities has not been comprehensively studied. The ability of a...... community to take up exogenous plasmid should, however, be an important element affecting the fate of mobile genetic elements released in the environment. We have devised a method to evaluate the permissiveness of a bacterial community towards exogenous plasmids, both quantitatively (how many bacteria can...... range plasmids, with common transfer across the Gram ‘barrier’. We next looked for factors that modulate permissiveness and, in particular, identified a taxon-specific effect imposed by metals when supplemented in concentrations that cause partial inhibition of the community metabolic activity. Overall...

  16. Spatial pattern affects diversity-productivity relationships in experimental meadow communities

    Science.gov (United States)

    Lamošová, Tereza; Doležal, Jiří; Lanta, Vojtěch; Lepš, Jan

    2010-05-01

    Plant species create aggregations of conspecifics as a consequence of limited seed dispersal, clonal growth and heterogeneous environment. Such intraspecific aggregation increases the importance of intraspecific competition relative to interspecific competition which may slow down competitive exclusion and promote species coexistence. To examine how spatial aggregation impacts the functioning of experimental assemblages of varying species richness, eight perennial grassland species of different growth form were grown in random and aggregated patterns in monocultures, two-, four-, and eight-species mixtures. In mixtures with an aggregated pattern, monospecific clumps were interspecifically segregated. Mixed model ANOVA was used to test (i) how the total productivity and productivity of individual species is affected by the number of species in a mixture, and (ii) how these relationships are affected by spatial pattern of sown plants. The main patterns of productivity response to species richness conform to other studies: non-transgressive overyielding is omnipresent (the productivity of mixtures is higher than the average of its constituent species so that the net diversity, selection and complementarity effects are positive), whereas transgressive overyielding is found only in a minority of cases (average of log(overyielding) being close to zero or negative). The theoretical prediction that plants in a random pattern should produce more than in an aggregated pattern (the distances to neighbours are smaller and consequently the competition among neighbours stronger) was confirmed in monocultures of all the eight species. The situation is more complicated in mixtures, probably as a consequence of complicated interplay between interspecific and intraspecific competition. The most productive species ( Achillea, Holcus, Plantago) were competitively superior and increased their relative productivity with mixture richness. The intraspecific competition of these species is

  17. Fermentation Conditions that Affect Clavulanic Acid Production in Streptomyces clavuligerus: A Systematic Review.

    Science.gov (United States)

    Ser, Hooi-Leng; Law, Jodi Woan-Fei; Chaiyakunapruk, Nathorn; Jacob, Sabrina Anne; Palanisamy, Uma Devi; Chan, Kok-Gan; Goh, Bey-Hing; Lee, Learn-Han

    2016-01-01

    The β-lactamase inhibitor, clavulanic acid is frequently used in combination with β-lactam antibiotics to treat a wide spectrum of infectious diseases. Clavulanic acid prevents drug resistance by pathogens against these β-lactam antibiotics by preventing the degradation of the β-lactam ring, thus ensuring eradication of these harmful microorganisms from the host. This systematic review provides an overview on the fermentation conditions that affect the production of clavulanic acid in the firstly described producer, Streptomyces clavuligerus. A thorough search was conducted using predefined terms in several electronic databases (PubMed, Medline, ScienceDirect, EBSCO), from database inception to June 30th 2015. Studies must involve wild-type Streptomyces clavuligerus, and full texts needed to be available. A total of 29 eligible articles were identified. Based on the literature, several factors were identified that could affect the production of clavulanic acid in S. clavuligerus. The addition of glycerol or other vegetable oils (e.g., olive oil, corn oil) could potentially affect clavulanic acid production. Furthermore, some amino acids such as arginine and ornithine, could serve as potential precursors to increase clavulanic acid yield. The comparison of different fermentation systems revealed that fed-batch fermentation yields higher amounts of clavulanic acid as compared to batch fermentation, probably due to the maintenance of substrates and constant monitoring of certain entities (such as pH, oxygen availability, etc.). Overall, these findings provide vital knowledge and insight that could assist media optimization and fermentation design for clavulanic acid production in S. clavuligerus. PMID:27148211

  18. Fermentation Conditions that Affect Clavulanic Acid Production in Streptomyces clavuligerus: A Systematic Review

    Science.gov (United States)

    Ser, Hooi-Leng; Law, Jodi Woan-Fei; Chaiyakunapruk, Nathorn; Jacob, Sabrina Anne; Palanisamy, Uma Devi; Chan, Kok-Gan; Goh, Bey-Hing; Lee, Learn-Han

    2016-01-01

    The β-lactamase inhibitor, clavulanic acid is frequently used in combination with β-lactam antibiotics to treat a wide spectrum of infectious diseases. Clavulanic acid prevents drug resistance by pathogens against these β-lactam antibiotics by preventing the degradation of the β-lactam ring, thus ensuring eradication of these harmful microorganisms from the host. This systematic review provides an overview on the fermentation conditions that affect the production of clavulanic acid in the firstly described producer, Streptomyces clavuligerus. A thorough search was conducted using predefined terms in several electronic databases (PubMed, Medline, ScienceDirect, EBSCO), from database inception to June 30th 2015. Studies must involve wild-type Streptomyces clavuligerus, and full texts needed to be available. A total of 29 eligible articles were identified. Based on the literature, several factors were identified that could affect the production of clavulanic acid in S. clavuligerus. The addition of glycerol or other vegetable oils (e.g., olive oil, corn oil) could potentially affect clavulanic acid production. Furthermore, some amino acids such as arginine and ornithine, could serve as potential precursors to increase clavulanic acid yield. The comparison of different fermentation systems revealed that fed-batch fermentation yields higher amounts of clavulanic acid as compared to batch fermentation, probably due to the maintenance of substrates and constant monitoring of certain entities (such as pH, oxygen availability, etc.). Overall, these findings provide vital knowledge and insight that could assist media optimization and fermentation design for clavulanic acid production in S. clavuligerus. PMID:27148211

  19. Molecular and population analyses of a recombination event in the catabolic plasmid pJP4.

    Science.gov (United States)

    Larraín-Linton, Juanita; De la Iglesia, Rodrigo; Melo, Francisco; González, Bernardo

    2006-10-01

    Cupriavidus necator JMP134(pJP4) harbors a catabolic plasmid, pJP4, which confers the ability to grow on chloroaromatic compounds. Repeated growth on 3-chlorobenzoate (3-CB) results in selection of a recombinant strain, which degrades 3-CB better but no longer grows on 2,4-dichlorophenoxyacetate (2,4-D). We have previously proposed that this phenotype is due to a double homologous recombination event between inverted repeats of the multicopies of this plasmid within the cell. One recombinant form of this plasmid (pJP4-F3) explains this phenotype, since it harbors two copies of the chlorocatechol degradation tfd gene clusters, which are essential to grow on 3-CB, but has lost the tfdA gene, encoding the first step in degradation of 2,4-D. The other recombinant plasmid (pJP4-FM) should harbor two copies of the tfdA gene but no copies of the tfd gene clusters. A molecular analysis using a multiplex PCR approach to distinguish the wild-type plasmid pJP4 from its two recombinant forms, was carried out. Expected PCR products confirming this recombination model were found and sequenced. Few recombinant plasmid forms in cultures grown in several carbon sources were detected. Kinetic studies indicated that cells containing the recombinant plasmid pJP4-FM were not selectable by sole carbon source growth pressure, whereas those cells harboring recombinant plasmid pJP4-F3 were selected upon growth on 3-CB. After 12 days of repeated growth on 3-CB, the complete plasmid population in C. necator JMP134 apparently corresponds to this form. However, wild-type plasmid forms could be recovered after growing this culture on 2,4-D, indicating that different plasmid forms can be found in C. necator JMP134 at the population level. PMID:16980481

  20. Do non-native plant species affect the shape of productivity-diversity relationships?

    Science.gov (United States)

    Drake, J.M.; Cleland, E.E.; Horner-Devine, M. C.; Fleishman, E.; Bowles, C.; Smith, M.D.; Carney, K.; Emery, S.; Gramling, J.; Vandermast, D.B.; Grace, J.B.

    2008-01-01

    The relationship between ecosystem processes and species richness is an active area of research and speculation. Both theoretical and experimental studies have been conducted in numerous ecosystems. One finding of these studies is that the shape of the relationship between productivity and species richness varies considerably among ecosystems and at different spatial scales, though little is known about the relative importance of physical and biological mechanisms causing this variation. Moreover, despite widespread concern about changes in species' global distributions, it remains unclear if and how such large-scale changes may affect this relationship. We present a new conceptual model of how invasive species might modulate relationships between primary production and species richness. We tested this model using long-term data on relationships between aboveground net primary production and species richness in six North American terrestrial ecosystems. We show that primary production and abundance of non-native species are both significant predictors of species richness, though we fail to detect effects of invasion extent on the shapes of the relationship between species richness and primary production.

  1. Nuclear DNA content affects the productivity of conifer forests by altering hydraulic architecture

    Science.gov (United States)

    Alday, Josu; Resco de Dios, Víctor

    2014-05-01

    Predictions of future global climate rely on feedbacks between terrestrial vegetation and the global carbon cycle, but the exact mechanisms underlying this relationship are still being discussed. One of the key knowledge gaps lies on the scaling of cellular processes to the ecosystem level. Here we examine whether an under-explored plant trait, inter-specific variation in the bulk amount of DNA in unreplicated somatic cells (2C DNA content), can explain inter-specific variation in the maximum productivity of conifer forests. We expected 2C DNA content to be negatively related to conifer productivity because: 1) it is positively correlated with cell volume (which, in turn, potentially affects structural features such as leaf mass area, a strong predictor of photosynthetic capacity); 2) it is positively correlated with stomatal size (with larger stomata leading to lower overall stomatal conductance and, by extension, lower CO2 uptake); and 3) larger genome sizes may reduce P availability in RNA (which has been hypothesized to slow growth). We present the results of regression and independent contrasts in different monospecific forests encompassing a 52º latitudinal gradient, each being dominated by 1 of 35 different conifer species. Contrary to expectations, we observed a positive correlation between genome size and maximum Gross Primary Productivity (R2 = 0.47) and also between genome size maximum tree height (R2 = 0.27). This correlation was apparently driven by the effects of genome size on stem hydraulics, since 2C DNA was positively correlated with wood density (R2 = 0.40) and also with resistance to cavitation (P50, R2 = 0.28). That is, increased genome sizes have a positive effect on the productivity of conifer forests by affecting the vascular tissues to increase their capacity for water transport. Our results shed a new light on the evolution of the vascular system of conifer forests and how they affect ecosystem productivity, and indicate the potential to

  2. Virulence Plasmids of Spore-Forming Bacteria.

    Science.gov (United States)

    Adams, Vicki; Li, Jihong; Wisniewski, Jessica A; Uzal, Francisco A; Moore, Robert J; McClane, Bruce A; Rood, Julian I

    2014-12-01

    Plasmid-encoded virulence factors are important in the pathogenesis of diseases caused by spore-forming bacteria. Unlike many other bacteria, the most common virulence factors encoded by plasmids in Clostridium and Bacillus species are protein toxins. Clostridium perfringens causes several histotoxic and enterotoxin diseases in both humans and animals and produces a broad range of toxins, including many pore-forming toxins such as C. perfringens enterotoxin, epsilon-toxin, beta-toxin, and NetB. Genetic studies have led to the determination of the role of these toxins in disease pathogenesis. The genes for these toxins are generally carried on large conjugative plasmids that have common core replication, maintenance, and conjugation regions. There is considerable functional information available about the unique tcp conjugation locus carried by these plasmids, but less is known about plasmid maintenance. The latter is intriguing because many C. perfringens isolates stably maintain up to four different, but closely related, toxin plasmids. Toxin genes may also be plasmid-encoded in the neurotoxic clostridia. The tetanus toxin gene is located on a plasmid in Clostridium tetani, but the botulinum toxin genes may be chromosomal, plasmid-determined, or located on bacteriophages in Clostridium botulinum. In Bacillus anthracis it is well established that virulence is plasmid determined, with anthrax toxin genes located on pXO1 and capsule genes on a separate plasmid, pXO2. Orthologs of these plasmids are also found in other members of the Bacillus cereus group such as B. cereus and Bacillus thuringiensis. In B. thuringiensis these plasmids may carry genes encoding one or more insecticidal toxins. PMID:26104459

  3. Comparative analysis of the replicon regions of eleven ColE2-related plasmids.

    OpenAIRE

    Hiraga, S; Sugiyama, T; Itoh, T.

    1994-01-01

    The incA gene product of ColE2-P9 and ColE3-CA38 plasmids is an antisense RNA that regulates the production of the plasmid-coded Rep protein essential for replication. The Rep protein specifically binds to the origin and synthesizes a unique primer RNA at the origin. The IncB incompatibility is due to competition for the Rep protein among the origins of the same binding specificity. We localized the regions sufficient for autonomous replication of 15 ColE plasmids related to ColE2-P9 and ColE...

  4. TLR-mediated NF-kB-dependent cytokine production is differently affected by HIV therapeutics

    DEFF Research Database (Denmark)

    Melchjorsen, Jesper; Paludan, Søren Riis; Mogensen, Trine; Tolstrup, Martin; Østergaard, Lars Jørgen

      Pathogen-recognizing Toll-like receptors 2 (TLR2) and TLR4 are known to recognize a number of pathogens, including E.Coli, S. Pneumonia and N. Meningococcus. We have studied whether a number of HIV therapeutics affect immediate proinflammatory cytokine responses in cell cultures. Preliminary...... results suggest an opposing effect of the drugs Tenofovir and Retrovir (AZT) on TLR-mediated production of NF-kappaB-dependent proinflammatory cytokines. We present data on the mechanisms behind the drug-mediated remodeling of innate immune activation and how the drugs effect early host...

  5. Does humor in radio advertising affect recognition of novel product brand names?

    Science.gov (United States)

    Berg, E M; Lippman, L G

    2001-04-01

    The authors proposed that item selection during shopping is based on brand name recognition rather than recall. College students rated advertisements and news stories of a simulated radio program for level of amusement (orienting activity) before participating in a surprise recognition test. Humor level of the advertisements was varied systematically, and content was controlled. According to signal detection analysis, humor did not affect the strength of recognition memory for brand names (nonsense units). However, brand names and product types were significantly more likely to be associated when appearing in humorous advertisements than in nonhumorous advertisements. The results are compared with prior findings concerning humor and recall. PMID:11506048

  6. Tn5-induced pBS286 plasmid mutations blocking early stages of napthalene oxidation

    International Nuclear Information System (INIS)

    The authors present data on the further analysis of the structural and functional organization of the nah region of plasmid pBS286 controlling the constitutive oxidation of naphthalene by Pseudomonas putida cells. They have studied Tn5-induced mutations blocking early stages of naphthalene oxidation. They present and discuss data providing evidence that, in contrast to plasmid NAH7, the mechanism of regulation of the nahl operon of plasmid NPL-1, the parent plasmid of plasmid pBS286, with inducible synthesis of naphthalene dioxygenase can include elements of a negative control with participation of the regulatory locus R, located proximal to the structural nah genes and closely linked to or overlapped by the inverted control DNA segment (4.2 kb). They also present data on the possibility of regulation of the activity of the catechol-splitting meta-pathway genes with the participation of products of early stages of naphthalene oxidation

  7. Reconstruction of the yeast 2 micron plasmid partitioning mechanism.

    OpenAIRE

    Dobson, M J; Yull, F E; Molina, M.; Kingsman, S M; Kingsman, A J

    1988-01-01

    The effect of the yeast 2 micron circle encoded REP1 and REP2 gene products on plasmid partitioning and copy number control was analyzed by removing the open reading frames from their normal sequence context and transcriptional control regions and directing their expression using heterologous promoters in [cir0] host strains. Both the REP1 and REP2 gene products are directly required at appropriate levels of expression to reconstitute the 2 microns circle partitioning system in conjunction wi...

  8. Does Mixed Reimbursement Schemes Affect Hospital Activity and Productivity? An Analysis of the Case of Denmark

    DEFF Research Database (Denmark)

    Hansen, Xenia Brun; Bech, Mickael; Jakobsen, Mads Leth;

    2013-01-01

    literature with a deeper understanding of such mixed reimbursement systems as well as empirically by identifying key design factors that determines the incentives embedded in such a mixed model. Furthermore, we describe how incentives vary in different designs of the mixed reimbursement scheme and assess...... whether different incentives affects the performance of hospitals regarding activity and productivity differently. Information on Danish reimbursement schemes has been collected from documents provided by the regional governments and through interviews with regional administrations. The data cover the...... period from 2007-2010. A theoretical framework identified the key factors in an ABF/block grant model to be the proportion of the national Diagnosis-Related Group (DRG) tariff above and below a predefined production target (i.e. the baseline); baseline calculations; the presence of kinks/ceilings; and...

  9. An Affective Prototyping Approach for the User-Satisfying Assistive Products

    DEFF Research Database (Denmark)

    Lai, Yoke Chin

    2013-01-01

    This paper outlines the key concepts of a study whose main aim is to devise an integrated design method for efficiently designing usable assistive products. The study grounds on Affective Design principle formulated for user’s needs, emotions and experience handling in an attempt to outline an...... integrated approach so that the key concept of participatory design could be practiced. Incorporating the maturing Augmented Reality technology is expected to create a design setting that could motivate active end-user involvement from the start throughout the product design process. With the aids of...... ontological modeling approach, the design setting is envisioned suitable for disabled and elderly end users participation and to support capturing the abstract but valuable user’s real needs that are influenced by emotions and experiences. The ontology model will outline the basis of a design knowledge...

  10. Factors Affecting Pheromone Production by the Pepper Weevil, Anthonomus eugenii Cano (Coleoptera: Curculionidae and Collection Efficiency

    Directory of Open Access Journals (Sweden)

    Fred J. Eller

    2014-11-01

    Full Text Available Several factors affecting pheromone production by male pepper weevils, Anthonomus eugenii Cano (Coleoptera: Curculionidae as well as collection efficiency were investigated. Factors studied included: porous polymer adsorbents (Tenax versus Super Q, male age, time of day, male density, and male diet. Super Q was found to be a superior adsorbent for the male-produced alcohols and geranic acid as well as the plant-produced E-β-ocimene. Pheromone production increased with male age up to about age 15 days old and then tapered off. Male pepper weevils produced the highest amount of pheromone between noon and 2 pm (i.e., 4 to 6 h after “lights on” and were producing ca. 800 ng/h during this period. Thereafter, pheromone production decreased and was extremely low during the scotophase (i.e., ca. 12 ng/h. Male pepper weevil density had a significant effect on both release rate and pheromone composition. Pheromone production on a per male basis was highest for individual males and the percentage of geranic acid in the blend was lowest for individual males. Male pepper weevils produced only extremely low amounts of pheromone when feeding on artificial diet; however, they produced very high amounts when on fresh peppers. Together, this information will be useful in designing better attractant lures for pepper weevils.

  11. Factors affecting the milk production of dairy cattle in northern rural areas of Bangladesh

    Directory of Open Access Journals (Sweden)

    M.R. Begum

    2014-12-01

    Full Text Available A cross sectional study was conducted to observe the factors affecting the productive performance of dairy cattle from northern rural areas of Bangladesh during July and September 2013. Data of 105 cows, 85 (80.95% from local and 20 (19.05% cows from cross breed, were randomly selected for the study. A binary logistic regression, expressed by odds ratio with 95% confidence interval, was done to determine the association of daily milk production categorized into ≤ 2 and > 2 liters (L, based on median, with the significant explanatory variables of body weight, age at first calving, lactation period, vitamin use, type of floor and milking person. The result demonstrated that the probability of milk production of >2 L was 6.16, 4.5, 20.65 and 5.7 times higher from the with animal body weight of >140 kg, age at first calving of >36 m, lactation period of >8 m and vitamin use than that of body weight of 140 kg, age at first calving of ≤36 m, lactation period of ≤ 8 m, and not vitamin used respectively. The chance of milk production of > 2 L was 0.25 and 0.22 times lower for mud floor, and owner milking than that of brick floor and gowala (professional milking person respectively.

  12. Homemade Site Directed Mutagenesis of Whole Plasmids

    Science.gov (United States)

    Laible, Mark; Boonrod, Kajohn

    2009-01-01

    Site directed mutagenesis of whole plasmids is a simple way to create slightly different variations of an original plasmid. With this method the cloned target gene can be altered by substitution, deletion or insertion of a few bases directly into a plasmid. It works by simply amplifying the whole plasmid, in a non PCR-based thermocycling reaction. During the reaction mutagenic primers, carrying the desired mutation, are integrated into the newly synthesized plasmid. In this video tutorial we demonstrate an easy and cost effective way to introduce base substitutions into a plasmid. The protocol works with standard reagents and is independent from commercial kits, which often are very expensive. Applying this protocol can reduce the total cost of a reaction to an eighth of what it costs using some of the commercial kits. In this video we also comment on critical steps during the process and give detailed instructions on how to design the mutagenic primers. PMID:19488024

  13. Plasmid and chromosome partitioning: surprises from phylogeny

    DEFF Research Database (Denmark)

    Gerdes, Kenn; Møller-Jensen, Jakob; Bugge Jensen, Rasmus

    2000-01-01

    Plasmids encode partitioning genes (par) that are required for faithful plasmid segregation at cell division. Initially, par loci were identified on plasmids, but more recently they were also found on bacterial chromosomes. We present here a phylogenetic analysis of par loci from plasmids...... and chromosomes from prokaryotic organisms. All known plasmid-encoded par loci specify three components: a cis-acting centromere-like site and two trans-acting proteins that form a nucleoprotein complex at the centromere (i.e. the partition complex). The proteins are encoded by two genes in an operon...... that is autoregulated by the par-encoded proteins. In all cases, the upstream gene encodes an ATPase that is essential for partitioning. Recent cytological analyses indicate that the ATPases function as adaptors between a host-encoded component and the partition complex and thereby tether plasmids and chromosomal...

  14. Factors Affecting sex pheromone production in female cotton leaf worm moth, Spodoptera littoralis (boisd.)

    International Nuclear Information System (INIS)

    Factors influencing sex pheromone production in the cotton leaf worm female moth with emphasis on gamma radiation were investigated. To determine the effect of age on sex pheromone production, ether extracts of the female abdominal tips were prepared from virgin females of various ages in a concentration of 0.01 FE/mu L. Each female extract was tested against 1-2 days-old males. The obtained results indicated that virgin females could secrete sex pheromone early at the beginning of their life. The pheromone production increased rapidly to reach its maximum on the second day. To study the effect of daytime on sex pheromone production, the ether extracts of 1-2 days old virgin female abdominal tips were prepared at 3 hour-intervals, throughout the photo phase and scotophase in a concentration of 0.01 FE/mu L. The obtained results indicated that pheromone production showed a minimum concentration at mid-day during the photo phase. It then increased to a moderate concentration from 7:0 p.m. to 10:0 p.m. and reached its maximum titer at almost mid-night. The obtained data on the effect of gamma irradiation indicated that irradiation of 3 and 6-day-old female pupae with doses of 60 and 120 Gy, respectively caused a reduction of 28.1 and 27.3 % in male response, respectively, to female sex pheromone extracts. When full-grown female pupae were irradiated with 200 and 350 Gy, a reduction of 15.6 and 75% in male response, respectively, was reached. Thus, an irradiation dose of 350 Gy applied to full-grown female pupae could severely affect pheromone production of the emerging female moths

  15. Development and application of automated systems for plasmid-based functional proteomics to improve syntheitc biology of engineered industrial microbes for high level expression of proteases for biofertilizer production

    Science.gov (United States)

    In addition to microarray technology, which provides a robust method to study protein function in a rapid, economical, and proteome-wide fashion, plasmid-based functional proteomics is an important technology for rapidly obtaining large quantities of protein and determining protein function across a...

  16. Soil water repellency affects production and transport of CO2 and CH4 in soil

    Science.gov (United States)

    Urbanek, Emilia; Qassem, Khalid

    2016-04-01

    Soil moisture is known to be vital in controlling both the production and transport of C gases in soil. Water availability regulates the decomposition rates of soil organic matter by the microorganisms, while the proportion of water/air filled pores controls the transport of gases within the soil and at the soil-atmosphere interface. Many experimental studies and process models looking at soil C gas fluxes assume that soil water is uniformly distributed and soil is easily wettable. Most soils, however, exhibit some degree of soil water repellency (i.e. hydrophobicity) and do not wet spontaneously when dry or moderately moist. They have restricted infiltration and conductivity of water, which also results in extremely heterogeneous soil water distribution. This is a world-wide occurring phenomenon which is particularly common under permanent vegetation e.g. forest, grass and shrub vegetation. This study investigates the effect of soil water repellency on microbial respiration, CO2 transport within the soil and C gas fluxes between the soil and the atmosphere. The results from the field monitoring and laboratory experiments show that soil water repellency results in non-uniform water distribution in the soil which affects the CO2 and CH4 gas fluxes. The main conclusion from the study is that water repellency not only affects the water relations in the soil, but has also a great impact on greenhouse gas production and transport and therefore should be included as an important parameter during the sites monitoring and modelling of gas fluxes.

  17. Nocturnal Light Pulses Lower Carbon Dioxide Production Rate without Affecting Feed Intake in Geese.

    Science.gov (United States)

    Huang, De-Jia; Yang, Shyi-Kuen

    2016-03-01

    This study was conducted to investigate the effect of nocturnal light pulses (NLPs) on the feed intake and metabolic rate in geese. Fourteen adult Chinese geese were penned individually, and randomly assigned to either the C (control) or NLP group. The C group was exposed to a 12L:12D photoperiod (12 h light and 12 h darkness per day), whereas the NLP group was exposed to a 12L:12D photoperiod inserted by 15-min lighting at 2-h intervals in the scotophase. The weight of the feed was automatically recorded at 1-min intervals for 1 wk. The fasting carbon dioxide production rate (CO2 PR) was recorded at 1-min intervals for 1 d. The results revealed that neither the daily feed intake nor the feed intakes during both the daytime and nighttime were affected by photoperiodic regimen, and the feed intake during the daytime did not differ from that during the nighttime. The photoperiodic treatment did not affect the time distribution of feed intake. However, NLPs lowered (p<0.05) the mean and minimal CO2 PR during both the daytime and nighttime. Both the mean and minimal CO2 PR during the daytime were significantly higher (p<0.05) than those during the nighttime. We concluded that NLPs lowered metabolic rate of the geese, but did not affect the feed intake; both the mean and minimal CO2 PR were higher during the daytime than during the nighttime. PMID:26950871

  18. pLS010 plasmid vector

    Science.gov (United States)

    Lacks, Sanford A.; Balganesh, Tanjore S.

    1988-01-01

    Disclosed is recombinant plasmid pLS101, consisting essentially of a 2.0 Kb malM gene fragment ligated to a 4.4 Kb T.sub.c r DNA fragment, which is particularly useful for transforming Gram-positive bacteria. This plasmid contains at least four restriction sites suitable for inserting exogeneous gene sequences. Also disclosed is a method for plasmid isolation by penicillin selection, as well as processes for enrichment of recombinant plasmids in Gram-positive bacterial systems.

  19. Chromate resistance plasmid in Pseudomonas fluorescens.

    OpenAIRE

    Bopp, L H; Chakrabarty, A M; Ehrlich, H. L.

    1983-01-01

    Chromate resistance of Pseudomonas fluorescens LB300, isolated from chromium-contaminated sediment in the upper Hudson River, was found to be plasmid specified. Loss of the plasmid (pLHB1) by spontaneous segregation or mitomycin C curing resulted in a simultaneous loss of chromate resistance. Subsequent transformation of such strains with purified pLHB1 plasmid DNA resulted in a simultaneous re-acquisition of the chromate resistance phenotype and the plasmid. When pLHB1 was transferred by con...

  20. ANALYSIS OF A MODEL OF PLASMID-BEARING, PLASMID-FREE COMPETITION IN A PULSED CHEMOSTAT

    OpenAIRE

    XIANGYUN SHI; XINYU SONG; XUEYONG ZHOU

    2006-01-01

    We introduce and study a chemostat model with plasmid-bearing, plasmid-free competition and impulsive effect. According to the stability analysis of the boundary periodic solution, we obtain the invasion threshold of the plasmid-free organism and plasmid-bearing organism. Furthermore, by using standard techniques of bifurcation theory, we prove the system has a positive τ-periodic solution, which shows that the impulsive effect destroys the equilibria of the unforced continuous system and ini...

  1. Plasmid ColVBtrp maintenance in Erwinia carotovora.

    OpenAIRE

    Schukin, N N

    1981-01-01

    Plasmid ColVBtrp maintenance in Erwinia carotovora cells was followed by measuring kinetics of elimination of plasmid genetic markers and loss of plasmid deoxyribonucleic acid. An E. carotovora mutant stably carrying plasmid ColVBtrp was isolated. Besides stable plasmid maintenance, the mutant showed altered sensitivity to male-specific phage MS2, sensitivity to drugs, and colony morphology.

  2. Docosahexaenoic diet supplementation, exercise and temperature affect cytokine production by lipopolysaccharide-stimulated mononuclear cells.

    Science.gov (United States)

    Capó, Xavier; Martorell, Miquel; Sureda, Antoni; Batle, Juan Miguel; Tur, Josep Antoni; Pons, Antoni

    2016-09-01

    Acute exercise induces changes in peripheral mononuclear cells' (PBMCs) capabilities to produce cytokines. The aim was to investigate the effect of docosahexaenoic acid (DHA) diet supplementation on cytokine production, by lipopolysaccharide (LPS)-stimulated PBMCs after exercise, and the in vitro influence of temperature. Fifteen male soccer players were randomly assigned to a placebo or an experimental group. The experimental group consumed an almond-based beverage enriched with DHA (1.16 g DHA/day) for 8 weeks, whereas the placebo group consumed a similar non-enriched beverage. Blood samples were taken before and after the nutritional intervention in basal conditions and 2 h after acute exercise. Nutritional intervention significantly increased the DHA content in erythrocytes only in experimental group (from 34 ± 3.6 to 43 ± 3.6 nmols DHA/10(9) erythrocytes). Exercise significantly increased Toll-like receptor 4 (TLR4) in PBMCs but only in the placebo group (203 %). Exercise also significantly increased IL6, IL8, VEGF, INFγ, TNFα, IL1α, IL1β, MCP1, and EGG production rates by LPS-stimulated PBMCs, and this response was attenuated by DHA supplementation. Temperature but not DHA also affected the pattern of cytokine production increasing IL6, IL8, IL1β, and MCP1 synthesis. The higher change was evidenced in IL1β increasing the production rate at 39.5 °C from 3.19 ± 0.77 to 22.4 ± 6.1 pg/h 10(6) PBMC in placebo and from 2.36 ± 0.11 to 10.6 ± 0.38 pg/h 10(6) PBMC in the supplemented group. The profile of affected cytokines differs between temperature and exercise, suggesting a different PBMC activation pathway. DHA diet supplementation only attenuated cytokine production after exercise and not that induced by temperature. PMID:27139422

  3. The expression of a plasmid-specified exported protein causes structural plasmid instability in Bacillus subtilis

    NARCIS (Netherlands)

    Cordes, C.; Meima, R; Twiest, B; Kazemier, B; Venema, G; vanDijl, JM; Bron, S

    1996-01-01

    The rolling-circle plasmid pGP1 was used to study the effects of the expression of a plasmid-specified exported protein on structural plasmid stability in Bacillus subtilis. pGP1 contains a fusion between the Bacillus licheniformis penP gene, encoding a C-terminally truncated penicillinase, and the

  4. Factors affecting the corrosion of SiC layer by fission product palladium

    International Nuclear Information System (INIS)

    HTR is one of the advanced nuclear reactors which has inherent safety system, graphite moderated and helium gas cooled. In general, these reactors are designed with the TRISO coated particle consist of four coating layers that are porous pyrolytic carbon (PyC). inner dense PyC (IPyC), silicon carbide (SiC), and outer dense PyC (OPyC). Among the four coating layers, the SiC plays an important role beside in retaining metallic fission products, it also provides mechanical strength to fuel particle. However, results of post irradiation examination indicate that fission product palladium can react with and corrode SiC layer, This assessment is conducted to get the comprehension about resistance of SiC layer on irradiation effects, especially in order to increase the fuel bum-up. The result of this shows that the corrosion of SiC layer by fission product palladium is beside depend on the material characteristics of SiC, and also there are other factors that affect on the SiC layer corrosion. Fuel enrichment, bum-up, and irradiation time effect on the palladium flux in fuel kernel. While, the fuel density, vapour pressure of palladium (the degree depend on the irradiation temperature and kernel composition) effect on palladium migration in fuel particle. (author)

  5. New product, familiar taste: Effects of slogans on cognitive and affective responses to an unknown food product among food neophobics and neophilics

    NARCIS (Netherlands)

    Fenko, A.; Leufkens, Jean-Marie; Hoof, van J.J.

    2015-01-01

    Food neophobia is considered a potential barrier for the introduction of new food products. This study investigated how advertising slogans could influence cognitive and affective responses to a new product in food neophobics and food neophilics. An unknown dairy product was used to examine the effe

  6. How the Structure of Mesoscale Precipitation Systems Affects their Production of Transient Luminous Events

    Science.gov (United States)

    Lang, T. J.; Lyons, W.; Rutledge, S. A.; Cummer, S. A.; MacGorman, D. R.

    2011-12-01

    Recently, Lang et al. (2010) analyzed the parent lightning of transient luminous events (TLEs) in the context of the structure and evolution of two mesoscale convective systems (MCSs). These two MCSs were very different - one a giant symmetric leading-line/trailing stratiform storm, and one a small asymmetric MCS that contained a mesoscale convective vortex. These structural differences were associated with substantially different TLE-parent lightning structure as well as TLE production. The results suggested that TLE (especially sprite) production, and TLE-parent positive charge altitude, depend on MCS morphology. Current work is focused on analyzing the structure, evolution, lightning behavior, and TLE production of additional MCSs over various regions of the United States. Several additional TLE-producing MCS cases already have been identified for the years 2008-2010, featuring a variety of organizational modes (symmetric, asymmetric, and other more exotic varieties) in different meteorological regimes (including some cold-season cases). More cases will be incorporated as they occur and are observed. Data sources include geostationary satellite imagery, Doppler radar, three-dimensional lightning mapping networks, ground-strike detection networks, charge moment change measurements, and low-light video observations. The ultimate goal is to further test the hypothesis that MCS structure affects TLE production, and if so to quantify its impact. Research on two Oklahoma case studies, a multicellular system that occurred on 24 March 2009 and a classic bow-echo MCS that occurred on 19 August 2009, is ongoing. Over a 2.5-h period, the March case produced 23 observed TLEs (all sprites) whose parent flashes occurred within 175 km of the Oklahoma Lightning Mapping Array (OKLMA). The median altitude of LMA sources during the TLEs was 5.9 km above Mean Sea Level (MSL), or -19.2 °C. The August storm produced, in 2.5 hours, 34 TLEs (all sprites) with 32 of those having parent

  7. Low-dose plasmid DNA treatment increases plasma vasopressin and regulates blood pressure in experimental endotoxemia

    Directory of Open Access Journals (Sweden)

    Malardo Thiago

    2012-11-01

    Full Text Available Abstract Background Although plasmid DNA encoding an antigen from pathogens or tumor cells has been widely studied as vaccine, the use of plasmid vector (without insert as therapeutic agent requires further investigation. Results Here, we showed that plasmid DNA (pcDNA3 at low doses inhibits the production of IL-6 and TNF-α by lipopolysaccharide (LPS-stimulated macrophage cell line J774. These findings led us to evaluate whether plasmid DNA could act as an anti-inflammatory agent in a Wistar rat endotoxemia model. Rats injected simultaneously with 1.5 mg/kg of LPS and 10 or 20 μg of plasmid DNA had a remarkable attenuation of mean arterial blood pressure (MAP drop at 2 hours after treatment when compared with rats injected with LPS only. The beneficial effect of the plasmid DNA on MAP was associated with decreased expression of IL-6 in liver and increased concentration of plasma vasopressin (AVP, a known vasoconstrictor that has been investigated in hemorrhagic shock management. No difference was observed in relation to nitric oxide (NO production. Conclusion Our results demonstrate for the first time that plasmid DNA vector at low doses presents anti-inflammatory property and constitutes a novel approach with therapeutic potential in inflammatory diseases.

  8. Diversity of plasmids encoding histidine decarboxylase gene in Tetragenococcus spp. isolated from Japanese fish sauce.

    Science.gov (United States)

    Satomi, Masataka; Furushita, Manabu; Oikawa, Hiroshi; Yano, Yutaka

    2011-07-15

    Nineteen isolates of histamine producing halophilic bacteria were isolated from four fish sauce mashes, each mash accumulating over 1000 ppm of histamine. The complete sequences of the plasmids encoding the pyruvoyl dependent histidine decarboxylase gene (hdcA), which is harbored in histamine producing bacteria, were determined. In conjunction, the sequence regions adjacent to hdcA were analyzed to provide information regarding its genetic origin. As reference strains, Tetragenococcus halophilus H and T. muriaticus JCM10006(T) were also studied. Phenotypic and 16S rRNA gene sequence analyses identified all isolates as T. halophilus, a predominant histamine producing bacteria present during fish sauce fermentation. Genetic analyses (PCR, Southern blot, and complete plasmid sequencing) of the histamine producing isolates confirmed that all the isolates harbored approximately 21-37 kbp plasmids encoding a single copy of the hdc cluster consisting of four genes related to histamine production. Analysis of hdc clusters, including spacer regions, indicated >99% sequence similarity among the isolates. All of the plasmids sequenced encoded traA, however genes related to plasmid conjugation, namely mob genes and oriT, were not identified. Two putative mobile genetic elements, ISLP1-like and IS200-like, respectively, were identified in the up- and downstream region of the hdc cluster of all plasmids. Most of the sequences, except hdc cluster and two adjacent IS elements, were diverse among plasmids, suggesting that each histamine producers harbored a different histamine-related plasmid. These results suggested that the hdc cluster was not spread by clonal dissemination depending on the specific plasmid and that the hdc cluster in tetragenococcal plasmid was likely encoded on transformable elements. PMID:21616548

  9. Environmental factors influencing trace house gas production in permafrost-affected soils

    Science.gov (United States)

    Walz, Josefine; Knoblauch, Christian; Böhme, Luisa; Pfeiffer, Eva-Maria

    2016-04-01

    The permafrost-carbon feedback has been identified as a major feedback mechanism to climate change. Soil organic matter (SOM) decomposition in the active layer and thawing permafrost is an important source of atmospheric carbon dioxide (CO2) and methane (CH4). Decomposability and potential CO2 and CH4 production are connected to the quality of SOM. SOM quality varies with vegetation composition, soil type, and soil depth. The regulating factors affecting SOM decomposition in permafrost landscapes are not well understood. Here, we incubated permafrost-affected soils from a polygonal tundra landscape in the Lena Delta, Northeast Siberia, to examine the influence of soil depth, oxygen availability, incubation temperature, and fresh organic matter addition on trace gas production. CO2 production was always highest in topsoil (0 - 10 cm). Subsoil (10 - 50 cm) and permafrost (50 - 90 cm) carbon did not differ significantly in their decomposability. Under anaerobic conditions, less SOM was decomposed than under aerobic conditions. However, in the absence of oxygen, CH4 can also be formed, which has a substantially higher warming potential than CO2. But, within the four-month incubation period (approximate period of thaw), methanogenesis played only a minor role with CH4 contributing 1-30% to the total anaerobic carbon release. Temperature and fresh organic matter addition had a positive effect on SOM decomposition. Across a temperature gradient (1, 4, 8°C) aerobic decomposition in topsoil was less sensitive to temperature than in subsoil or permafrost. The addition of labile plant organic matter (13C-labelled Carex aquatilis, a dominant species in the region) significantly increased overall CO2 production across different depths and temperatures. Partitioning the total amount of CO2 in samples amended with Carex material into SOM-derived CO2 and Carex-derived CO2, however, revealed that most of the additional CO2 could be assigned to the organic carbon from the amendment

  10. Factors affecting remote handling productivity during installation of the ITER-like wall at JET

    International Nuclear Information System (INIS)

    Highlights: ► The paper describes the challenges to achieve the installation of the ILW beryllium sliced wall. ► Examines the factual difference between estimated remote handling in-vessel durations and those achieved, with a view to quantifying the typical disparity between the two. ► The paper will elaborate and highlight the contributing factors. This offers an opportunity to provide provenance for availability estimates of devices such as ITER and DEMO. ► The paper will identify and describe the factors influencing the ratio between estimated versus the actual durations for remote handling operations. -- Abstract: Remote handling operations at JET have encountered many challenges to achieve the installation of the ILW beryllium sliced wall during the Enhanced Performance stage 2 (EP2) shutdown of JET. This was a demanding and challenging activity which was based on the experience gained from a period of over 15 years (20,000 h operations) of JET In-Vessel remote handling operations. This paper describes the difference between estimated remote handling in-vessel durations and those actually achieved with a view to quantifying the typical disparity between them. There are many factors that affect productivity of the remote handling operations and it is important to accommodate these either in the design of the component or within the production of the operational procedures with a view to minimise all impact on the final task duration. Some factors that affect the efficiency are outside the control of the design and operational procedures. These are unforeseen anomalies that were encountered during the removal, naked wall survey and installation of the components. Recoveries from these anomalies are extremely challenging and need to be addressed efficiently in order to minimise the impact on the shutdown duration and prevent optimised panned activities from becoming inefficient by fragmentation

  11. Conservation of plasmids among Escherichia coli K1 isolates of diverse origins.

    OpenAIRE

    Mercer, A. A.; Morelli, G.; Heuzenroeder, M; Kamke, M; Achtman, M.

    1984-01-01

    Escherichia coli K1 isolates of various O types were previously assigned to different clonal groups. Members of the two clones defined by membrane pattern 9 (MP9) and serotypes O18:K1 and O1:K1 had been found to be very similar to each other. The plasmid contents of these bacteria confirmed this conclusion. Both groups carried a self-transmissible plasmid of the FI incompatibility group that coded for colicin production and a major outer membrane protein called the plasmid-coded protein (PCP)...

  12. Regulation of plasmid virulence gene expression in Salmonella dublin involves an unusual operon structure.

    OpenAIRE

    Krause, M.; Fang, F C; Guiney, D G

    1992-01-01

    The 80-kb plasmid pSDL2 of Salmonella dublin Lane is essential for lethal systemic infection in experimental mice. A cluster of five plasmid genes, designated spvR, spvA, spvB, spvC, and spvD, is sufficient to express the plasmid-related virulent phenotype. The spvR gene product has recently been identified as a positive regulator of spvB expression in the stationary phase of bacterial growth (F. C. Fang, M. Krause, C. Roudier, J. Fierer, and D. G. Guiney, J. Bacteriol. 173:6783-6789, 1991). ...

  13. Isolation of Plasmid DNA from Butyrivibrio fibrisolvens†

    OpenAIRE

    Teather, Ronald M.

    1982-01-01

    A procedure based on successive precipitation of cell lysates with sodium dodecyl sulfate-NaCl and polyethylene glycol 6000 was developed which allows the isolation of plasmid DNA from Butyrivibrio fibrisolvens. A survey of B. fibrisolvens strains isolated from the bovine rumen showed that plasmids are a common feature of this species.

  14. Plasmid deoxyribonucleic acid replication in Streptomyces griseus.

    OpenAIRE

    Xue, Y.; Zhuang, Z.; Zhu, Y.; Xu, Y.; Dong, K.

    1981-01-01

    A series of electron micrographs showing the presence of different molecular forms representing various replication stages of plasmid deoxyribonucleic acid from Streptomyces griseus was obtained. Based upon an analysis of these electron micrographs, a tentative model for plasmid deoxyribonucleic acid replication in S. griseus is proposed.

  15. Plasmid Vectors for Xylella fastidiosa Utilizing a Toxin-Antitoxin System for Stability in the Absence of Antibiotic Selection.

    Science.gov (United States)

    Burbank, Lindsey P; Stenger, Drake C

    2016-08-01

    The phytopathogen Xylella fastidiosa causes disease in a variety of important crop and landscape plants. Functional genetic studies have led to a broader understanding of virulence mechanisms used by this pathogen in the grapevine host. Plasmid shuttle vectors are important tools in studies of bacterial genetics but there are only a limited number of plasmid vectors available that replicate in X. fastidiosa, and even fewer that are retained without antibiotic selection. Two plasmids are described here that show stable replication in X. fastidiosa and are effective for gene complementation both in vitro and in planta. Plasmid maintenance is facilitated by incorporation of the PemI/PemK plasmid addiction system, consisting of PemK, an endoribonuclease toxin, and its cognate antitoxin, PemI. Vector pXf20pemIK utilizes a native X. fastidiosa replication origin as well as a high-copy-number pUC origin for propagation in Escherichia coli cloning strains. Broad-host-range vector pBBR5pemIK is a medium- to low-copy-number plasmid based on the pBBR1 backbone. Both plasmids are maintained for extended periods of time in the absence of antibiotic selection, as well as up to 14 weeks in grapevine, without affecting bacterial fitness. These plasmids present an alternative to traditional complementation and expression vectors which rely on antibiotic selection for plasmid retention. PMID:27088393

  16. Factors affecting wild rabbit production in extensive breeding enclosures: how can we optimise efforts?

    Directory of Open Access Journals (Sweden)

    José Guerrero-Casado

    2013-09-01

    Full Text Available The declining rabbit population in the Iberian Peninsula has led hunters and authorities to rear rabbits in captivity systems for their subsequent release. One alternative method to intensive rabbitry systems is the use of extensive breeding enclosures, since they produce animals of greater quality for hunting and conservation purposes. However, some of the factors that affect rabbit production in breeding enclosures are still unknown. The present study used partial least squares regression (PLSR to analyse the effects of plot size, scrub cover, slope, initial rabbit abundance, the resources needed to dig warrens, predation and proximity to other enclosures on rabbit abundance. The results of our study show a positive effect of the number of other fenced plots within a radius of 3 km, a positive relationship with the availability of optimal resources for building warrens and a positive influence of intermediate values of scrub cover. According to our results, to maximise rabbit production in the enclosures it would be advisable to concentrate the restocking effort by ensuring that the restocking plots are close to each other, thus avoiding isolated enclosures. Furthermore, the selection of plots with an appropriate scrub cover and high availability of elements that favour the construction of warrens, such as large stones, sloping land or tall shrubs, may optimise results.

  17. Optimization of factors affecting the production of biodiesel from crude palm kernel oil and ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Kuwornoo, David. K. [Faculty of Chemical and Materials Engineering, Kwame Nkrumah University of Science and Technology (KNUST), Private Mail Bag, Kumasi (Ghana); Ahiekpor, Julius C. [Chemical Engineering Department, Kumasi Polytechnic, P.O. Box 854, Kumasi (Ghana)

    2010-07-01

    Biodiesel, an alternative diesel fuel made from renewable sources such as vegetable oils and animal fats, has been identified by government to play a key role in the socio-economic development of Ghana. The utilization of biodiesel is expected to be about 10% of the total liquid fuel mix of the country by the year 2020. Despite this great potential and the numerous sources from which biodiesel could be developed in Ghana, studies on the sources of biodiesel and their properties as a substitute for fossil diesel have tended to be limited to Jatropha oil. This paper, however, reports the parameters that influences the production of biodiesel from palm kernel oil, one of the vegetable oils obtained from oil palm which is the highest vegetable oil source in Ghana. The parameters studied are; mass ratio of ethanol to oil, reaction temperature, catalyst concentration, and reaction time using completely randomized 24 factorial design. Results indicated that ethanol to oil mass ratio, catalyst concentration and reaction time were the most important factors affecting the ethyl ester yield. There was also an interaction effect between catalyst and time and ethanol- oil ratio and time on the yield. Accordingly, the optimal conditions for the production of ethyl esters from crude palm kernel oil were determined as; 1:5 mass ratio of ethanol to oil, 1% catalyst concentration by weight of oil, 90 minutes reaction time at a temperature of 30 deg C.

  18. Stress responses in pathogenic Yersinia enterocolitica with reference to the stability of the virulence plasmid in food

    Science.gov (United States)

    Yersinia enterocolitica has been associated with food-borne illness, most often due the ingestion of pork products. The pathogenic effects induced by a Y. enterocolitica infection are caused by the interplay of chromosomal genes and a virulence plasmid, pYV. Generally, the plasmid is lost during g...

  19. The sigma factor sigma s affects antibiotic production and biological control activity of Pseudomonas fluorescens Pf-5.

    Science.gov (United States)

    Sarniguet, A; Kraus, J; Henkels, M D; Muehlchen, A M; Loper, J E

    1995-12-19

    Pseudomonas fluorescens Pf-5, a rhizosphere-inhabiting bacterium that suppresses several soilborne pathogens of plants, produces the antibiotics pyrrolnitrin, pyoluteorin, and 2,4-diacetylphloroglucinol. A gene necessary for pyrrolnitrin production by Pf-5 was identified as rpoS, which encodes the stationary-phase sigma factor sigma s. Several pleiotropic effects of an rpoS mutation in Escherichia coli also were observed in an RpoS- mutant of Pf-5. These included sensitivities of stationary-phase cells to stresses imposed by hydrogen peroxide or high salt concentration. A plasmid containing the cloned wild-type rpoS gene restored pyrrolnitrin production and stress tolerance to the RpoS- mutant of Pf-5. The RpoS- mutant overproduced pyoluteorin and 2,4-diacetyl-phloroglucinol, two antibiotics that inhibit growth of the phytopathogenic fungus Pythium ultimum, and was superior to the wild type in suppression of seedling damping-off of cucumber caused by Pythium ultimum. When inoculated onto cucumber seed at high cell densities, the RpoS- mutant did not survive as well as the wild-type strain on surfaces of developing seedlings. Other stationary-phase-specific phenotypes of Pf-5, such as the production of cyanide and extracellular protease(s) were expressed by the RpoS- mutant, suggesting that sigma s is only one of the sigma factors required for the transcription of genes in stationary-phase cells of P. fluorescens. These results indicate that a sigma factor encoded by rpoS influences antibiotic production, biological control activity, and survival of P. fluorescens on plant surfaces. PMID:8618880

  20. Plasmid-mediated horizontal gene transfer is a coevolutionary process

    OpenAIRE

    Harrison, Ellie; Brockhurst, Michael A

    2012-01-01

    Conjugative plasmids are key agents of horizontal gene transfer (HGT) that accelerate bacterial adaptation by vectoring ecologically important traits between strains and species. However, although many conjugative plasmids carry beneficial traits, all plasmids exert physiological costs-of-carriage on bacteria. The existence of conjugative plasmids, therefore, presents a paradox because non-beneficial plasmids should be lost to purifying selection, whereas beneficial genes carried on plasmids ...

  1. Exfoliative toxin plasmids of bacteriophage group 2 Staphylococcus aureus: sequence homology.

    OpenAIRE

    Warren, R. L.

    1980-01-01

    The plasmid contents of seven exfoliative toxin-producing strains of phage group 2 Staphylococcus aureus were analyzed by agarose gel electrophoresis and deoxyribonucleic acid-deoxyribonucleic acid hybridization. All strains were found to contain a large plasmid with a molecular weight of 27 X 10(6) except for strain RW1005. A comparison of the restriction endonuclease cleavage products by agarose gel electrophoresis showed that the number and size distribution of the fragments of all these T...

  2. CpG-free plasmid expression cassettes for cystic fibrosis gene therapy.

    Science.gov (United States)

    Pringle, Ian A; Hyde, Stephen C; Connolly, Mary M; Lawton, Anna E; Xu, Bihui; Nunez-Alonso, Graciela; Davies, Lee A; Sumner-Jones, Stephanie G; Gill, Deborah R

    2012-10-01

    Clinical studies are underway for the aerosol delivery of plasmid DNA complexed with Genzyme Lipid GL67A to the lungs of patients with cystic fibrosis (CF). Plasmid vectors contain several functional elements all of which play a role in determining the efficacy of the final clinical product. To optimise the final plasmid, variations of CpG-free 5' enhancer elements and 3'UTR regions were inserted into a common CpG-free, plasmid backbone containing Luciferase or CFTR transgenes. Plasmids were compared in immortalised cell culture, human airway liquid interface primary cell cultures, and mouse lung models to determine which design directed optimal transgene expression. Following aerosol delivery to mouse lung, plasmids containing the murine CMV enhancer showed higher peak Luciferase activity than the human CMV enhancer, but the human version resulted in persistent expression. In cell culture, the SV40 3'UTR and a novel BGH2 3'UTR exhibited up to 20-fold higher Luciferase activity than the commonly used BGH 3'UTR, but in mouse lung aerosol studies the activity and duration was greater for BGH 3'UTR. Systematic evaluation of each functional component of the plasmid has resulted in an improved design, exhibiting superior levels and duration of lung gene expression. PMID:22727465

  3. Soil hydraulic properties affected by topsoil thickness in cultivated switchgrass and corn-soybean rotation production systems

    Science.gov (United States)

    Loss of productive topsoil by soil erosion over time can reduce the productive capacity of soil and can significantly affect soil hydraulic properties. This study evaluated the effects of reduced topsoil thickness and perennial switchgrass (Panicum virgatum L.) versus corn (Zea mays L.)/soybean [Gly...

  4. Bifurcation Analysis of a Chemostat Model of Plasmid-Bearing and Plasmid-Free Competition with Pulsed Input

    OpenAIRE

    Zhong Zhao; Baozhen Wang; Liuyong Pang; Ying Chen

    2014-01-01

    A chemostat model of plasmid-bearing and plasmid-free competition with pulsed input is proposed. The invasion threshold of the plasmid-bearing and plasmid-free organisms is obtained according to the stability of the boundary periodic solution. By use of standard techniques of bifurcation theory, the periodic oscillations in substrate, plasmid-bearing, and plasmid-free organisms are shown when some conditions are satisfied. Our results can be applied to control bioreactor aimed at producing co...

  5. Characterisation of TNF block haplotypes affecting the production of TNF and LTA.

    Science.gov (United States)

    Tan, J H; Temple, S E L; Kee, C; Waterer, G W; Tan, C R T; Gut, I; Price, P

    2011-02-01

    Polymorphisms in the central major histocompatibility complex (MHC) (particularly TNF and adjacent genes) associate with several immunopathological diseases and with susceptibility to pneumonia. The MHC is characterised by strong linkage disequilibrium (LD), so identification of loci affecting disease must be based on haplotypes. We have defined 31 tumour necrosis factor (TNF) block haplotypes (denoted FV1-31) in Caucasians, Asians and Australian Aboriginals. This study correlates the carriage of TNF block haplotypes with TNF and lymphotoxin alpha (LTA) protein production by peripheral blood mononuclear cells from 205 healthy Caucasian subjects, following in vitro stimulation with Streptococcus pneumoniae (S. pneumoniae; gram-positive bacteria), Escherichia coli (E. coli; gram-negative bacteria) or TNF over 4, 8 and 24 h. Fifteen haplotypes were present at >1%, accounting for 94.5% of the cohort. The haplotypes were grouped into five families based on common alleles. Following stimulation, cells from carriers of the FV10 haplotype (family 2) produced less LTA compared with non-FV10 carriers. Carriers of the FV18 haplotype (family 4) produced more LTA than other donors. Induction of TNF by S. pneumoniae following 24 h stimulation was also greater in donors with FV18. The FV18 haplotype associated with the 44.1 MHC ancestral haplotype (HLA-A2, -C5, -B44, -DRB1*0401 and -DQB1*0301) that has few disease associations. FV16 occurred in the 8.1 MHC haplotype (HLA-A2, B8, DR3) that is associated with multiple immunopathological diseases. FV16 did not affect TNF or LTA levels. The findings suggest that many genetic variations critical in vivo are not effectively modelled by short-term cultures. PMID:21214521

  6. Factors affecting the efficiency of foal production in a commercial oocyte transfer program.

    Science.gov (United States)

    Riera, Fernando L; Roldán, Jaime E; Gomez, José; Hinrichs, Katrin

    2016-04-01

    Transfer of donor oocytes to the oviducts of inseminated recipient mares (oocyte transfer, OT) presents a valuable method for production of foals from otherwise infertile mares. Little information is available, however, on factors affecting success of OT in a clinical setting. We report the findings over three breeding seasons in a commercial OT program developed at an equine embryo transfer center in Argentina. Overall, 25 mares were enrolled, and 197 follicle aspiration procedures were performed. The average mare age was 23 years. Follicle aspiration was performed with a needle placed through the flank; the oocyte recovery rate per follicle aspirated was 149 of 227 (66%). Induction of donor ovulation with deslorelin + hCG resulted in a significantly higher oocyte recovery rate than did induction with deslorelin alone (75% vs. 58%). There was no significant effect of mare age (17-20, 21-24, or 25-27 years) on oocyte recovery rate. Twelve oocytes were degenerating or lost during handling; transfer of the remaining 137 oocytes resulted in 42 pregnancies (31%) at 14 days. Of these, 32 (23% per transfer) went on to produce a foal or ongoing pregnancy. Transfer of oocytes recovered with a compact cumulus, without donor follicle induction, or less than 20 hours after induction was associated with a significantly reduced pregnancy rate (1/16, 6%), as was use of noncycling, hormone-treated recipients (2/22, 9%). To evaluate management factors affecting pregnancy rate, noncycling, hormone-treated recipients were disregarded, and only procedures using mature (expanded cumulus) oocytes recovered and transferred on the standard schedule (n = 99) were included. Mare age did not significantly affect rates of pregnancy or pregnancy loss. Similar pregnancy rates were obtained using recipients inseminated from 1 to 27 hours before transfer. Counterintuitively, insemination of recipients immediately (1-2 hours) after aspiration of the recipient follicle was associated with

  7. Variable Isoflavone Contents of Red Clover Products Affect Intestinal Disposition of Biochanin A, Formononetin, Genistein and Daidzein

    OpenAIRE

    Wang, Stephen W. J.; Chen, Yan; Joseph, Tiby; Ming HU

    2008-01-01

    Marketed red clover products use a wide variety of labels and the isoflavone contents from the lable is ambiguous. In the present study, we analyzed the content of various isoflavone products, and determined a) the content and b) how sample matrix of red clover products affects intestinal disposition of main isoflavones within it using the human intestinal Caco-2 cell model. Analysis using high and ultra-performance liquid chromatography indicates that the isoflavone content varied significan...

  8. Assessment of cultivation factors that affect biomass and geraniol production in transgenic tobacco cell suspension cultures.

    Directory of Open Access Journals (Sweden)

    Nikolay Vasilev

    Full Text Available A large-scale statistical experimental design was used to determine essential cultivation parameters that affect biomass accumulation and geraniol production in transgenic tobacco (Nicotiana tabacum cv. Samsun NN cell suspension cultures. The carbohydrate source played a major role in determining the geraniol yield and factors such as filling volume, inoculum size and light were less important. Sucrose, filling volume and inoculum size had a positive effect on geraniol yield by boosting growth of plant cell cultures whereas illumination of the cultures stimulated the geraniol biosynthesis. We also found that the carbohydrates sucrose and mannitol showed polarizing effects on biomass and geraniol accumulation. Factors such as shaking frequency, the presence of conditioned medium and solubilizers had minor influence on both plant cell growth and geraniol content. When cells were cultivated under the screened conditions for all the investigated factors, the cultures produced ∼ 5.2 mg/l geraniol after 12 days of cultivation in shaking flasks which is comparable to the yield obtained in microbial expression systems. Our data suggest that industrial experimental designs based on orthogonal arrays are suitable for the selection of initial cultivation parameters prior to the essential medium optimization steps. Such designs are particularly beneficial in the early optimization steps when many factors must be screened, increasing the statistical power of the experiments without increasing the demand on time and resources.

  9. Predicting the Affects of Climate Change on Evapotranspiration and Agricultural Productivity of Semi-arid Basins

    Science.gov (United States)

    Peri, L.; Tyler, S. W.; Zheng, C.; Pohll, G. M.; Yao, Y.

    2013-12-01

    Many arid and semi-arid regions around the world are experiencing water shortages that have become increasingly problematic. Since the late 1800s, upstream diversions in Nevada's Walker River have delivered irrigation supply to the surrounding agricultural fields resulting in a dramatic water level decline of the terminal Walker Lake. Salinity has also increased because the only outflow from the lake is evaporation from the lake surface. The Heihe River basin of northwestern China, a similar semi-arid catchment, is also facing losses from evaporation of terminal locations, agricultural diversions and evapotranspiration (ET) of crops. Irrigated agriculture is now experiencing increased competition for use of diminishing water resources while a demand for ecological conservation continues to grow. It is important to understand how the existing agriculture in these regions will respond as climate changes. Predicting the affects of climate change on groundwater flow, surface water flow, ET and agricultural productivity of the Walker and Heihe River basins is essential for future conservation of water resources. ET estimates from remote sensing techniques can provide estimates of crop water consumption. By determining similarities of both hydrologic cycles, critical components missing in both systems can be determined and predictions of impacts of climate change and human management strategies can be assessed.

  10. Could Crop Height Affect the Wind Resource at Agriculturally Productive Wind Farm Sites?

    Science.gov (United States)

    Vanderwende, Brian; Lundquist, Julie K.

    2016-03-01

    The collocation of cropland and wind turbines in the US Midwest region introduces complex meteorological interactions that could influence both agriculture and wind-power production. Crop management practices may affect the wind resource through alterations of land-surface properties. We use the weather research and forecasting (WRF) model to estimate the impact of crop height variations on the wind resource in the presence of a large turbine array. A hypothetical wind farm consisting of 121 1.8-MW turbines is represented using the WRF model wind-farm parametrization. We represent the impact of selecting soybeans rather than maize by altering the aerodynamic roughness length in a region approximately 65 times larger than that occupied by the turbine array. Roughness lengths of 0.1 and 0.25 m represent the mature soy crop and a mature maize crop, respectively. In all but the most stable atmospheric conditions, statistically significant hub-height wind-speed increases and rotor-layer wind-shear reductions result from switching from maize to soybeans. Based on simulations for the entire month of August 2013, wind-farm energy output increases by 14 %, which would yield a significant monetary gain. Further investigation is required to determine the optimal size, shape, and crop height of the roughness modification to maximize the economic benefit and minimize the cost of such crop-management practices. These considerations must be balanced by other influences on crop choice such as soil requirements and commodity prices.

  11. Cowpea production as affected by dry spells in no-tillage and conventional crop systems

    Directory of Open Access Journals (Sweden)

    Rômulo Magno Oliveira de Freitas

    2013-12-01

    Full Text Available The objective of this study was to evaluate the effect of different periods of water shortage in no-tillage and conventional crop systems on cowpea yield components and grain yield in the Mossoró-RN region. For this, an experiment was conducted using two tillage systems (conventional and no-tillage subjected to periods of irrigation suspension (2; 6; 10; 14; 18 end 22 days, started at flowering (34 days after sowing. Plants were harvested 70 days after sowing, and the studied variables were: Pods length (CV, number of grains per pod (NGV, number of pods per plant (NPP, the hundred grains weight (PCG and grain yield (kg ha-1. The no-tillage system is more productive than the conventional under both irrigation and water stress treatments. The water stress length affected grain yield and all yield components studied in a negative way, except for the hundred grains weight. Among the systems studied, the no-tillage provides higher values for the yield components, except the hundred grains weight.

  12. PcrA function in plasmid replication

    OpenAIRE

    Chisty, L. T.

    2014-01-01

    PcrA is a DNA helicase involved in unwinding plasmi ds as a part of a complex in asymmetric rolling - circle replication of certain plasmids carrying antibiotic resistance genes. PcrA translocates on single stranded DNA by coupling ATP hydrolysis to movement on DNA. Initiator protein, RepD is required to nick supercoiled plasmid site - specifically and open an ssDNA stretch that PcrA can bind. The presence of RepD is needed throughout plasmid unwinding to maintain processivity. Using fluo...

  13. Isolation, sequence analysis, and comparison of two plasmids (28 and 29 kilobases) from the biomining bacterium Leptospirillum ferrooxidans ATCC 49879.

    Science.gov (United States)

    Coram, Nicolette J; van Zyl, Leonardo J; Rawlings, Douglas E

    2005-11-01

    Two plasmids, of 28,878 bp and 28,012 bp, were isolated from Leptospirillum ferrooxidans ATCC 49879. Altogether, a total of 67 open reading frames (ORFs) were identified on both plasmids, of which 32 had predicted products with high homology to proteins of known function, while 11 ORFs had predicted products with homology to previously identified proteins of unknown function. Twenty-four ORFs had products with no homologues in the GenBank/NCBI database. An analysis of the ORFs and other features of the two plasmids, the first to be isolated from a bacterium of the genus Leptospirillum, is presented. PMID:16269793

  14. Development of a Novel Reference Plasmid for Accurate Quantification of Genetically Modified Kefeng6 Rice DNA in Food and Feed Samples

    OpenAIRE

    Liang Li; Xiujie Zhang; Yusong Wan; Wujun Jin

    2013-01-01

    Reference plasmids are an essential tool for the quantification of genetically modified (GM) events. Quantitative real-time PCR (qPCR) is the most commonly used method to characterize and quantify reference plasmids. However, the precision of this method is often limited by calibration curves, and qPCR data can be affected by matrix differences between the standards and samples. Here, we describe a digital PCR (dPCR) approach that can be used to accurately measure the novel reference plasmid ...

  15. Marker-free plasmids for gene therapeutic applications--lack of antibiotic resistance gene substantially improves the manufacturing process.

    Science.gov (United States)

    Mairhofer, Jürgen; Cserjan-Puschmann, Monika; Striedner, Gerald; Nöbauer, Katharina; Razzazi-Fazeli, Ebrahim; Grabherr, Reingard

    2010-04-01

    Plasmid DNA is being considered as a promising alternative to traditional protein vaccines or viral delivery methods for gene therapeutic applications. DNA-based products are highly flexible, stable, are easily stored and can be manufactured on a large scale. Although, much safer than viral approaches, issues have been raised with regard to safety due to possible integration of plasmid DNA into cellular DNA or spread of antibiotic resistance genes to intestinal bacteria by horizontal gene transfer. Accordingly, there is interest in methods for the production of plasmid DNA that lacks the antibiotic resistance gene to further improve their safety profile. Here, we report for the first time the gram-scale manufacturing of a minimized plasmid that is devoid of any additional sequence elements on the plasmid backbone, and merely consists of the target expression cassette and the bacterial origin of replication. Three different host/vector combinations were cultivated in a fed-batch fermentation process, comparing the progenitor strain JM108 to modified strains JM108murselect, hosting a plasmid either containing the aminoglycoside phosphotransferase which provides kanamycin resistance, or a marker-free variant of the same plasmid. The metabolic load exerted by expression of the aminoglycoside phosphotransferase was monitored by measuring ppGpp- and cAMP-levels. Moreover, we revealed that JM108 is deficient of the Lon protease and thereby refined the genotype of JM108. The main consequences of Lon-deficiency with regard to plasmid DNA production are discussed herein. Additionally, we found that the expression of the aminoglycoside phosphotransferase, conferring resistance to kanamycin, was very high in plasmid DNA producing processes that actually inclusion bodies were formed. Thereby, a severe metabolic load on the host cell was imposed, detrimental for overall plasmid yield. Hence, deleting the antibiotic resistance gene from the vector backbone is not only beneficial

  16. TOL plasmid carriage enhances biofilm formation and increases extracellular DNA content in Pseudomonas putida KT2440

    DEFF Research Database (Denmark)

    D'Alvise, Paul; Sjoholm, O.R.; Yankelevich, T.;

    2010-01-01

    Adherent growth of Pseudomonas putida KT2440 with and without the TOL plasmid (pWWO) at the solid-liquid and air-liquid interface was examined. We compared biofilm formation on glass in flow cells, and assayed pellicle (air-liquid interface biofilm) formation in stagnant liquid cultures by confocal...... laser scanning microscopy. The TOL-carrying strains formed pellicles and thick biofilms, whereas the same strains without the plasmid displayed little adherent growth. Microscopy using fluorescent nucleic acid-specific stains revealed differences in the production of extracellular polymeric substances......: TOL carriage leads to more extracellular DNA (eDNA) in pellicles and biofilms. Pellicles were dissolved by DNase I treatment. Enhanced cell lysis due to plasmid carriage was ruled out as the mechanism for eDNA release. We report, for the first time, that carriage of a conjugative plasmid leads to...

  17. TOL Plasmid Carriage Enhances Biofilm Formation and Increases Extracellular DNA Content in Pseudomonas Putida KT2440

    DEFF Research Database (Denmark)

    Smets, Barth F.; D'Alvise, Paul; Yankelovich, T.;

    Adherent growth of Pseudomonas putida KT2440 with and without the TOL plasmid (pWWO) at the solid-liquid and air-liquid interface was examined. We compared biofilm formation on glass in flow cells, and assayed pellicle (air-liquid interface biofilm) formation in stagnant liquid cultures by confocal...... laser scanning microscopy. The TOL-carrying strains formed pellicles and thick biofilms, whereas the same strains without the plasmid displayed little adherent growth. Microscopy using fluorescent nucleic acid- specific stains (cytox orange, propidium iodide) revealed differences in production...... combined with specific cytostains; release of cytoplasmic material was assayed by a β-glucosidase assay. Enhanced cell lysis due to plasmid carriage was ruled out as the mechanism for eDNA release. We report, for the first time, that carriage of a conjugative plasmid leads to increased biofilm formation...

  18. Overlap extension PCR cloning: a simple and reliable way to create recombinant plasmids.

    Science.gov (United States)

    Bryksin, Anton V; Matsumura, Ichiro

    2010-06-01

    Here we describe a straightforward, efficient, and reliable way to clone an insert of choice into a plasmid of choice without restriction endonucleases or T4 DNA ligase. Chimeric primers containing plasmid sequence at the 5' ends and insert sequence at the 3' ends were used to PCR-amplify insertion sequences of various sizes, namely the genes for GFP (gfp), beta-d-glucuronidase (gusA), and beta-galactosidase (lacZ), as well as the entire luxABCDE operon. These inserts were employed as mega-primers in a second PCR with a circular plasmid template. The original plasmid templates were then destroyed in restriction digests with DpnI, and the overlap extension PCR products were used to transform competent Escherichia coli cells. Phusion DNA polymerase was used for the amplification and fusion reactions, so both reactions were easy to monitor and optimize. PMID:20569222

  19. 40 CFR 63.5795 - How do I know if my reinforced plastic composites production facility is a new affected source or...

    Science.gov (United States)

    2010-07-01

    ... composites production facility is a new affected source or an existing affected source? 63.5795 Section 63... for Hazardous Air Pollutants: Reinforced Plastic Composites Production What This Subpart Covers § 63.5795 How do I know if my reinforced plastic composites production facility is a new affected source...

  20. Long-term affected energy production of waste to energy technologies identified by use of energy system analysis

    DEFF Research Database (Denmark)

    Münster, Marie; Meibom, Peter

    2010-01-01

    Affected energy production is often decisive for the outcome of consequential life-cycle assessments when comparing the potential environmental impact of products or services. Affected energy production is however difficult to determine. In this article the future long-term affected energy produc...... such as storage of heat and waste as well as expansion of district heating networks. Finally, inflexible technologies such as nuclear power plants are shown to be affected....... production is identified by use of energy system analysis. The focus is on different uses of waste for energy production. The Waste-to-Energy technologies analysed include co-combustion of coal and waste, anaerobic digestion and thermal gasification. The analysis is based on optimization of both investments...... and production of electricity, district heating and bio-fuel in a future possible energy system in 2025 in the countries of the Northern European electricity market (Denmark, Norway, Sweden, Finland and Germany). Scenarios with different CO2 quota costs are analysed. It is demonstrated that the waste...

  1. Plasmids as Tools for Containment.

    Science.gov (United States)

    García, José L; Díaz, Eduardo

    2014-10-01

    Active containment systems are a major tool for reducing the uncertainty associated with the introduction of monocultures, genetically engineered or not, into target habitats for a large number of biotechnological applications (e.g., bioremediation, bioleaching, biopesticides, biofuels, biotransformations, live vaccines, etc.). While biological containment reduces the survival of the introduced organism outside the target habitat and/or upon completion of the projected task, gene containment strategies reduce the lateral spread of the key genetic determinants to indigenous microorganisms. In fundamental research, suicide circuits become relevant tools to address the role of gene transfer, mainly plasmid transfer, in evolution and how this transfer contributes to genome plasticity and to the rapid adaptation of microbial communities to environmental changes. Many lethal functions and regulatory circuits have been used and combined to design efficient containment systems. As many new genomes are being sequenced, novel lethal genes and regulatory elements are available, e.g., new toxin-antitoxin modules, and they could be used to increase further the current containment efficiencies and to expand containment to other organisms. Although the current containment systems can increase the predictability of genetically modified organisms in the environment, containment will never be absolute, due to the existence of mutations that lead to the appearance of surviving subpopulations. In this sense, orthogonal systems (xenobiology) appear to be the solution for setting a functional genetic firewall that will allow absolute containment of recombinant organisms. PMID:26104372

  2. Enhancement of plasmid-mediated gene therapy for muscular dystrophy by directed plasmid integration

    OpenAIRE

    Bertoni, Carmen; Jarrahian, Sohail; Wheeler, Thurman M.; LI, YINING; Olivares, Eric C.; Michele P Calos; Rando, Thomas A.

    2005-01-01

    Plasmid-mediated gene therapy can restore dystrophin expression in skeletal muscle in the mdx mouse, a model of Duchenne muscular dystrophy. However, sufficient long-term expression and distribution of dystrophin remain a hurdle for translating this technology into a viable treatment for Duchenne muscular dystrophy. To improve plasmid-mediated gene therapy for muscle diseases, we studied the effects of targeted plasmid integration using a phage integrase (φC31) that can mediate the integratio...

  3. Policies Affecting Production Practices and Adoption of Integrated Pest Management for Jamaican Farmers in Ebony Park, Clarendon

    OpenAIRE

    Ogrodowczyk, Joseph Daniel

    1998-01-01

    Farmers' decisions to adopt Integrated Pest Management (IPM) technologies depend on the profitability of IPM systems relative to the traditional production methods. Government policies may affect the profitability of the IPM technologies. A linear programming model was developed and used to evaluate the economic incentives for adoption of Integrated Pest Mangement (IPM) practices by Jamaican farmers in Ebony Park, Clarendon. Further analysis was completed to determine the affect of policy ...

  4. Elimination of multicopy plasmid R6K by bleomycin.

    OpenAIRE

    Attfield, P V; Pinney, R. J.

    1985-01-01

    Bleomycin eliminated multicopy plasmid R6K from growing cells of Escherichia coli AB1157 but failed to cure either of the low-copy plasmids R1 or R46. Measurements of R6K-encoded beta-lactamase and of covalently closed plasmid DNA indicated that the drug causes a progressive reduction in plasmid copy number.

  5. Behavior of IncQ Plasmids in Agrobacterium tumefaciens

    NARCIS (Netherlands)

    Hille, Jacques; Schilperoort, Rob

    1981-01-01

    Inc-Q plasmids were introduced into Agrobacterium tumefuciens, by mobilization from Escherichia coli with an Inc-P plasmid, or by transformation with purified plasmid DNA. It was found that they were stably maintained. The presence of an Inc-Q plasmid did not influence tumorigenicity. These results

  6. Curing of plasmid pXO1 from Bacillus anthracis using plasmid incompatibility.

    Directory of Open Access Journals (Sweden)

    Xiankai Liu

    Full Text Available The large plasmid pXO1 encoding the anthrax toxin is important for the virulence of Bacillus anthracis. It is essential to cure pXO1 from B. anthracis to evaluate its role in the pathogenesis of anthrax infection. Because conventional methods for curing plasmids (e.g., curing agents or growth at elevated temperatures can induce mutations in the host chromosomal DNA, we developed a specific and reliable method to eliminate pXO1 from B. anthracis using plasmid incompatibility. Three putative replication origins of pXO1 were inserted into a temperature-sensitive plasmid to generate three incompatible plasmids. One of the three plasmids successfully eliminated the large plasmid pXO1 from B. anthracis vaccine strain A16R and wild type strain A16. These findings provided additional information about the replication/partitioning of pXO1 and demonstrated that introducing a small incompatible plasmid can generate plasmid-cured strains of B. anthracis without inducing spontaneous mutations in the host chromosome.

  7. Positive epistasis between co-infecting plasmids promotes plasmid survival in bacterial populations

    OpenAIRE

    San Millan, Alvaro; Heilbron, Karl; MacLean, R. Craig

    2014-01-01

    Plasmids have a key role in the horizontal transfer of genes among bacteria. Although plasmids are catalysts for bacterial evolution, it is challenging to understand how they can persist in bacterial populations over the long term because of the burden they impose on their hosts (the ‘plasmid paradox'). This paradox is especially perplexing in the case of ‘small' plasmids, which are unable to self-transfer by conjugation. Here, for the first time, we investigate how interactions between co-in...

  8. Mini-F plasmid genes that couple host cell division to plasmid proliferation.

    OpenAIRE

    Ogura, T; Hiraga, S

    1983-01-01

    A mechanism for stable maintenance of plasmids, besides the replication and partition mechanisms, has been found to be specified by genes of a mini-F plasmid. An oriC plasmid carrying both a mini-F segment necessary for partition [coordinates 46.4-49.4 kilobase pairs (kb) on the F map] and another segment (42.9-43.6 kb), designated ccd (coupled cell division), is more stably maintained than are oriC plasmids carrying only the partition segment; the stability is comparable to that of the paren...

  9. Adaptive Plasmid Evolution Results in Host-Range Expansion of a Broad-Host-Range Plasmid

    OpenAIRE

    De Gelder, Leen; Williams, Julia J.; Ponciano, José M; Sota, Masahiro; Eva M. Top

    2008-01-01

    Little is known about the range of hosts in which broad-host-range (BHR) plasmids can persist in the absence of selection for plasmid-encoded traits, and whether this “long-term host range” can evolve over time. Previously, the BHR multidrug resistance plasmid pB10 was shown to be highly unstable in Stenotrophomonas maltophilia P21 and Pseudomonas putida H2. To investigate whether this plasmid can adapt to such unfavorable hosts, we performed evolution experiments wherein pB10 was maintained ...

  10. Long-term affected energy production of waste to energy technologies identified by use of energy system analysis.

    Science.gov (United States)

    Münster, M; Meibom, P

    2010-12-01

    Affected energy production is often decisive for the outcome of consequential life-cycle assessments when comparing the potential environmental impact of products or services. Affected energy production is however difficult to determine. In this article the future long-term affected energy production is identified by use of energy system analysis. The focus is on different uses of waste for energy production. The Waste-to-Energy technologies analysed include co-combustion of coal and waste, anaerobic digestion and thermal gasification. The analysis is based on optimization of both investments and production of electricity, district heating and bio-fuel in a future possible energy system in 2025 in the countries of the Northern European electricity market (Denmark, Norway, Sweden, Finland and Germany). Scenarios with different CO(2) quota costs are analysed. It is demonstrated that the waste incineration continues to treat the largest amount of waste. Investments in new waste incineration capacity may, however, be superseded by investments in new Waste-to-Energy technologies, particularly those utilising sorted fractions such as organic waste and refuse derived fuel. The changed use of waste proves to always affect a combination of technologies. What is affected varies among the different Waste-to-Energy technologies and is furthermore dependent on the CO(2) quota costs and on the geographical scope. The necessity for investments in flexibility measures varies with the different technologies such as storage of heat and waste as well as expansion of district heating networks. Finally, inflexible technologies such as nuclear power plants are shown to be affected. PMID:20471819

  11. Long-term affected energy production of waste to energy technologies identified by use of energy system analysis

    International Nuclear Information System (INIS)

    Affected energy production is often decisive for the outcome of consequential life-cycle assessments when comparing the potential environmental impact of products or services. Affected energy production is however difficult to determine. In this article the future long-term affected energy production is identified by use of energy system analysis. The focus is on different uses of waste for energy production. The Waste-to-Energy technologies analysed include co-combustion of coal and waste, anaerobic digestion and thermal gasification. The analysis is based on optimization of both investments and production of electricity, district heating and bio-fuel in a future possible energy system in 2025 in the countries of the Northern European electricity market (Denmark, Norway, Sweden, Finland and Germany). Scenarios with different CO2 quota costs are analysed. It is demonstrated that the waste incineration continues to treat the largest amount of waste. Investments in new waste incineration capacity may, however, be superseded by investments in new Waste-to-Energy technologies, particularly those utilising sorted fractions such as organic waste and refuse derived fuel. The changed use of waste proves to always affect a combination of technologies. What is affected varies among the different Waste-to-Energy technologies and is furthermore dependent on the CO2 quota costs and on the geographical scope. The necessity for investments in flexibility measures varies with the different technologies such as storage of heat and waste as well as expansion of district heating networks. Finally, inflexible technologies such as nuclear power plants are shown to be affected.

  12. Advanced Glycation End-Products affect transcription factors regulating insulin gene expression

    International Nuclear Information System (INIS)

    Advanced Glycation End-Products (AGEs) are generated by the covalent interaction of reducing sugars with proteins, lipids or nucleic acids. AGEs are implicated in diabetic complications and pancreatic β-cell dysfunction. We previously demonstrated that exposure of the pancreatic islet cell line HIT-T15 to high concentrations of AGEs leads to a significant decrease of insulin secretion and content. Insulin gene transcription is positively regulated by the beta cell specific transcription factor PDX-1 (Pancreatic and Duodenal Homeobox-1). On the contrary, the forkhead transcription factor FoxO1 inhibits PDX-1 gene transcription. Activity of FoxO1 is regulated by post-translational modifications: phosphorylation deactivates FoxO1, and acetylation prevents FoxO1 ubiquitination. In this work we investigated whether AGEs affect expression and subcellular localization of PDX-1 and FoxO1. HIT-T15 cells were cultured for 5 days in presence of AGEs. Cells were then lysed and processed for subcellular fractionation. We determined intracellular insulin content, then we assessed the expression and subcellular localization of PDX-1, FoxO1, phosphoFoxO1 and acetylFoxO1. As expected intracellular insulin content was lower in HIT-T15 cells cultured with AGEs. The results showed that AGEs decreased expression and nuclear localization of PDX-1, reduced phosphorylation of FoxO1, and increased expression and acetylation of FoxO1. These results suggest that AGEs decrease insulin content unbalancing transcription factors regulating insulin gene expression.

  13. Population dynamics of dechlorinators and factors affecting the level and products of PCB dechlorination in sediments

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.S.; Sokol, R.C.; Liu, X.; Bethoney, C.M.; Rhee, G.Y. [State Univ. of New York and New York State Department of Health, Albany, NY (United States)

    1996-12-31

    Microbial dechlorination of polychlorinated biphenyls (PCBs) often stops although a significant number of removable chlorines remain. To determine the reason for the cessation, we investigated the limitation of organic carbon, PCB bioavailability, and inhibition by metabolic products. Enrichment with carbon sources did not induce additional chlorination, indicating the plateau was not due to depletion of organic carbon. The bioavailability was not limiting, since a subcritical micelle concentration of the surfactant, which enhanced desorption without inhibiting dechlorinating microorganisms, failed to lower the plateau. Neither was it due to accumulation of metabolites, since no additional dechlorination was detected when plateau sediments were incubated with fresh medium. Similarly, dechlorination was not inhibited in freshly spiked sediment slurries. Dechlorination ended up at the same level with nearly identical congener profiles, regardless of treatment. These results indicate that cessation of dechlorination was due to the accumulation of daughter congeners, which cannot be used as electron acceptors by microbes. To determine whether the decreasing availability affected the microorganisms, we determined the population dynamics of dechlorinators using the most probable number technique. The growth dynamics of the dechlorinators mirrored the time course of dechlorination. It started when the population increased by two orders of magnitude. Once dechlorination stopped the dechlorinating population also began to decrease. When dechlorinators were inoculated into PCB-free sediments, the population decreased over time. The decrease of the population as dechlorination ceased confirms that the diminishing availability of congeners was the reason for the incomplete dechlorination. Recent findings have shown that a second phase of dechlorination of certain congeners can occur after a long lag. 45 refs., 8 figs.

  14. Characterization of a Haemophilus ducreyi mobilizing plasmid.

    OpenAIRE

    McNicol, P J; Albritton, W L; Ronald, A R

    1986-01-01

    The OriV site of Haemophilus ducreyi mobilizing plasmid pHD147, determined by replication in Escherichia coli polA, is located close to the OriT site. The OriT site, located by recombination-proficient and -deficient cells, and the OriV site map in a region of pHD147 homologous to the beta-lactamase-specifying plasmids of H. ducreyi and Neisseria gonorrhoeae.

  15. Plasmid and chromosome segregation in prokaryotes

    DEFF Research Database (Denmark)

    Møller-Jensen, Jakob; Bugge Jensen, Rasmus; Gerdes, Kenn

    2000-01-01

    Recent major advances in the understanding of prokaryotic DNA segregation have been achieved by using fluorescence microscopy to visualize the localization of cellular components. Plasmids and bacterial chromosomes are partitioned in a highly dynamic fashion, suggesting the presence of a mitotic......-like apparatus in prokaryotes. The identification of chromosomal homologues of the well-characterized plasmid partitioning genes indicates that there could be a general mechanism of bacterial DNA partitioning. Udgivelsesdato: July 1...

  16. Plasmid Evolution and Interaction between the Plasmid Addiction Stability Systems of Two Related Broad-Host-Range IncQ-Like Plasmids

    OpenAIRE

    Deane, Shelly M.; Rawlings, Douglas E

    2004-01-01

    Plasmid pTC-F14 contains a plasmid stability system called pas (plasmid addiction system), which consists of two proteins, a PasA antitoxin and a PasB toxin. This system is closely related to the pas of plasmid pTF-FC2 (81 and 72% amino acid identity for PasA and PasB, respectively) except that the pas of pTF-FC2 contains a third protein, PasC. As both pTC-F14 and pTF-FC2 are highly promiscuous broad-host-range plasmids isolated from bacteria that share a similar ecological niche, the plasmid...

  17. Relationship between plasmid content and auxotype in Neisseria gonorrhoeae isolates.

    OpenAIRE

    Dillon, J R; Pauzé, M

    1981-01-01

    One hundred and forty strains of Neisseria gonorrhoeae, representing 12 different auxotype groups, were examined for differences in plasmid content. Most auxotype groups harbored a phenotypically cryptic 2,6-megadalton plasmid; a few groups also carried a 24.5-megadalton plasmid which has been previously characterized as a transfer plasmid. However, isolates of the proline-, citrulline-, and uracil-requiring (PCU-) auxotype were consistently free of plasmids. The correlation between auxotype ...

  18. Plasmid stability and maintenance of copy number using natural marker

    OpenAIRE

    Hamzah Basil Mohammed; Sudhakar Malla

    2015-01-01

    Present study was conducted to study the plasmid stability with the help of natural plasmid isolated from the bacteria which lodges the ink gland of the sea squid and emits bioluminescence. Isolated bacterial strain was identified by using 16srRNA sequencing and its plasmid DNA was used for the experimental studies. The plasmid is found to be responsible for the bioluminescence. The stability of this plasmid was studied in shake flask method using the different sugar sources (Gluc...

  19. Plasmid Segregation: Spatial Awareness at the Molecular Level

    DEFF Research Database (Denmark)

    Møller-Jensen, Jakob; Gerdes, Kenn

    2007-01-01

    In bacteria, low-copy number plasmids ensure their stable inheritance by partition loci (par), which actively distribute plasmid replicates to each side of the cell division plane. Using time-lapse fluorescence microscopic tracking of segregating plasmid molecules, a new study provides novel...... insight into the workings of the par system from Escherichia coli plasmid R1. Despite its relative simplicity, the plasmid partition spindle shares characteristics with the mitotic machinery of eukaryotic cells....

  20. Mobilization of Thiobacillus ferrooxidans plasmids among Escherichia coli strains.

    OpenAIRE

    Rawlings, D. E.; Woods, D R

    1985-01-01

    Nonconjugative Thiobacillus ferrooxidans plasmids were mobilized at high frequencies among Escherichia coli strains by the IncP plasmid RP4 and at low frequencies by the IncN plasmid R46, but not by the IncW plasmid pSa. The mobilization region of a nonconjugative T. ferrooxidans plasmid was located on a 5.3-kilobase T. ferrooxidans DNA fragment.

  1. Critical Factors Affecting the Success of Cloning, Expression, and Mass Production of Enzymes by Recombinant E. coli

    OpenAIRE

    Md. Fakruddin; Reaz Mohammad Mazumdar; Khanjada Shahnewaj Bin Mannan; Abhijit Chowdhury; Md. Nur Hossain

    2012-01-01

    E. coli is the most frequently used host for production of enzymes and other proteins by recombinant DNA technology. E. coli is preferable for its relative simplicity, inexpensive and fast high-density cultivation, well-known genetics, and large number of compatible molecular tools available. Despite all these advantages, expression and production of recombinant enzymes are not always successful and often result in insoluble and nonfunctional proteins. There are many factors that affect the s...

  2. Functionalized tetrapod-like ZnO nanostructures for plasmid DNA purification, polymerase chain reaction and delivery

    International Nuclear Information System (INIS)

    Functionalized tetrapodal ZnO nanostructures are tested in plasmid DNA experiments (1) as a solid-phase adsorbent for plasmid DNA purification (2) as improving reagents in a polymerase chain reaction (PCR) and (3) as novel carriers for gene delivery. The amino-modification, the tetrapod-like shape of the nanostructure and its high biocompatibility all contribute to measurements showing promise for applications. A sol-gel method is used for silica coating and amino-modification. Plasmid DNA is purified through reversible conjugations of amino-modified ZnO tetrapods with DNA. Also, as additional reagents, functionalized tetrapods are shown to improve the amount of PCR product. For transfection, ZnO tetrapods provide some protection against deoxyribonuclease cleavage of plasmid DNA and deliver plasmid DNA into cells with little cytotoxicity

  3. Factors affecting productivity and the role of customer relationship management: A case study of home appliance manufacturing

    Directory of Open Access Journals (Sweden)

    Saeed Mirzamohammadi

    2012-01-01

    Full Text Available In today's competitive world, productivity- as a core source of production - is the most important target of the organization. Experimental studies in developed industrial countries prove that productivity improvements resulted from development of management systems play a more important role in production than physical increases in labor and capital factors. This paper, while focusing on productivity from a CRM perspective, employs a European Organizational Excellence Model framework to identify factors affecting productivity and the role of CRM systems. We perform an empirical study for a case study of home appliance manufacturing and using a questionnaire computed present status and compared with desired status of CRM components such as customer leadership, strategy, skill and motivation of labor work, effective use of information technology and process management.

  4. Factors affecting the production of eremofortin C and PR toxin in Penicillium roqueforti.

    OpenAIRE

    Chang, S. C.; Wei, Y H; Wei, D L; Chen, Y. Y.; Jong, S C

    1991-01-01

    Eremofortin C (EC) and PR toxin are secondary metabolites of Penicillium roqueforti. Of 17 strains from the American Type Culture Collection that were studied for their ability to produce EC and PR toxin, 13 produced these metabolites. Toxin production by strains grown in solid media (10 cereals and 8 other agricultural products) was also investigated. Production of EC and PR toxin by fungi grown on cereals was greater than production of EC and PR toxin by fungi grown on legumes; fungi grown ...

  5. PRODUCT CHARACTERISTICS AFFECTING CONSUMERS' FRESH BEEF CUT PURCHASING DECISIONS IN THE UNITED STATES, JAPAN, AND AUSTRALIA

    OpenAIRE

    Erikson, Glade R.; Wahl, Thomas I.; Jussaume, Raymond A., Jr.; SHI, HONGQI

    1998-01-01

    The effects of product and economic characteristics on consumers who purchase six cuts of fresh beef (blocks/parts, steak, thinly sliced, diced, chopped, and ground) in urban areas of the United States, Japan, and Australia will be examined in this paper. Certain product characteristics (such as product freshness and display case cleanliness) were important to consumers of beef in all three countries while other product characteristics (such as price considerations for ground beef consumers) ...

  6. Plasmid selection in Escherichia coli using an endogenous essential gene marker

    Directory of Open Access Journals (Sweden)

    Good Liam

    2008-08-01

    Full Text Available Abstract Background Antibiotic resistance genes are widely used for selection of recombinant bacteria, but their use risks contributing to the spread of antibiotic resistance. In particular, the practice is inappropriate for some intrinsically resistant bacteria and in vaccine production, and costly for industrial scale production. Non-antibiotic systems are available, but require mutant host strains, defined media or expensive reagents. An unexplored concept is over-expression of a host essential gene to enable selection in the presence of a chemical inhibitor of the gene product. To test this idea in E. coli, we used the growth essential target gene fabI as the plasmid-borne marker and the biocide triclosan as the selective agent. Results The new cloning vector, pFab, enabled selection by triclosan at 1 μM. Interestingly, pFab out-performed the parent pUC19-ampicillin system in cell growth, plasmid stability and plasmid yield. Also, pFab was toxic to host cells in a way that was reversed by triclosan. Therefore, pFab and triclosan are toxic when used alone but in combination they enhance growth and plasmid production through a gene-inhibitor interaction. Conclusion The fabI-triclosan model system provides an alternative plasmid selection method based on essential gene over-expression, without the use of antibiotic-resistance genes and conventional antibiotics.

  7. Terroir et vignoble: how the farming management can affect the production of a quality wine

    Science.gov (United States)

    Gallo, Alba; Bini, Claudio

    2016-04-01

    Italian wine is one of the most exported wine in the world. The particular climate, the soil characteristics and other several factors have contributed to this success. Italy is located in the temperate belt, with a suitable climate for grapevine cultivation. For this reason, all regions in Italy produce wine, first of all the Veneto region, with 8.569.000 hl of wine in 2011. Wine quality derives from the perfect interaction among climate, morphology, soil and plant, i.e. the terroir. So, knowledge of the land characteristics, together with cultivation techniques and management, is essential to understand this interaction and the typicality of the wine. For example, large utilization of fertilizers and pesticides may determine accumulation of toxic substances in soil and possible translocation to the food chain. For this reason, metal contamination of soils and plants becomes a main issue in agricultural production. Therefore, our attention was focused on the determination of soil quality of the Prosecco DOCG (controlled and guaranteed denomination of origin) area, particularly in Conegliano. Conegliano is a town located in Veneto, in the province of Treviso, known for its wine. This wine variety is regulated by the Conegliano-Valdobbiadene production Consortium, to protect both consumers and producers. The goals of this research are: evaluation of trace metal content (Al ,Cd, Cr, Cu, Fe, Mg, Mn, Ni, P, Pb, V and Zn) in soils and possible uptake by grape leaves; estimation of biological soil quality (QBS-ar index); analysis of oxidative stress in dandelion (Taraxacum officinale) and grape leaves, by the Lipid peroxidation test (LPO test). Results concerning trace metal concentration show: i) a high content of Al, Mg and P in soils, and ii) high concentration of Al, Cu, Fe and Zn in grape leaves. High contents of Al in topsoil are consistent with the high concentration of organic matter. Instead, high Al contents in subsoil are related to clay. Mg and P are usually

  8. Changing nutrient stoichiometry affects phytoplankton production, DOP accumulation and dinitrogen fixation - A mesocosm experiment in the eastern tropical North Atlantic

    DEFF Research Database (Denmark)

    Meyer, J.; Löscher, C. R.; Neulinger, S. C.;

    2016-01-01

    Ocean deoxygenation due to climate change may alter redox-sensitive nutrient cycles in the marine environment. The productive eastern tropical North Atlantic (ETNA) upwelling region may be particularly affected when the relatively moderate oxygen minimum zone (OMZ) deoxygenates further and...

  9. 40 CFR Table 6 to Subpart Xxxx of... - Initial Compliance With the Emission Limits for Tire Production Affected Sources

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Initial Compliance With the Emission Limits for Tire Production Affected Sources 6 Table 6 to Subpart XXXX of Part 63 Protection of... Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX, Table 6 Table 6 to Subpart XXXX of Part...

  10. 40 CFR Table 10 to Subpart Xxxx of... - Continuous Compliance With the Emission Limits for Tire Production Affected Sources

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Continuous Compliance With the Emission Limits for Tire Production Affected Sources 10 Table 10 to Subpart XXXX of Part 63 Protection of... Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX, Table 10 Table 10 to Subpart XXXX of Part...

  11. 40 CFR Table 12 to Subpart Xxxx of... - Continuous Compliance With the Emission Limits for Tire Cord Production Affected Sources

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Continuous Compliance With the Emission Limits for Tire Cord Production Affected Sources 12 Table 12 to Subpart XXXX of Part 63 Protection of... Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX, Table 12 Table 12 to Subpart XXXX of Part...

  12. 40 CFR Table 7 to Subpart Xxxx of... - Initial Compliance With the Emission Limits for Tire Cord Production Affected Sources

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Initial Compliance With the Emission Limits for Tire Cord Production Affected Sources 7 Table 7 to Subpart XXXX of Part 63 Protection of... Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX, Table 7 Table 7 to Subpart XXXX of Part...

  13. Diversity and stability of plasmids from glycopeptide resistant Enterococcus faecium isolated from pigs in Denmark

    DEFF Research Database (Denmark)

    Hasman, H.; Villadsen, A. G.; Aarestrup, Frank Møller

    2005-01-01

    was seen at the end of the 7-year period, coinciding with the ban in 1998 of the macrolide tylosin as growth promoter for pig production. The stability of the plasmid in its original host was compared with stability of the same plasmid in BM4105RF, when both strains were maintained in liquid cultures......In this paper, we examine the plasmid variation between a subset of unrelated GRE isolated from pigs in Denmark between 1995 and 2001 (five from each of the years). The isolates were tested with PFGE, plasmid RFLP, and subsequently Southern blotting with an IS1216V probe. Of the 35 isolates, 31...... belonged to the same PFGE type (type 1), and the last four belonged to a completely different PFGE type (type II). All 35 isolates contained the same type of large plasmid (approximate size of 150-200 kb), which could be divided into eight different variant types (V0 to V7). Most variance among the plasmid...

  14. Investigation of diversity of plasmids carrying the blaTEM-52 gene

    DEFF Research Database (Denmark)

    Bielak, Eliza Maria; Bergenholtz, Rikke D.; Jørgensen, Mikael Skaanning; Sørensen, Søren J.; Hansen, Lars H.; Hasman, Henrik

    2011-01-01

    OBJECTIVES: To investigate the diversity of plasmids that carry blaTEM-52 genes among Escherichia coli and Salmonella enterica originating from animals, meat products and humans. METHODS: A collection of 22 blaTEM-52-encoding plasmids was characterized by restriction fragment length polymorphism...... demonstrated dissemination of blaTEM-52 in Denmark (imported meat from Germany), France, Belgium and the Netherlands from 2000 to 2006 by mainly two different plasmids, one encoding blaTEM-52b (IncX1A, 45 kb) and the other blaTEM-52c (IncI1, 80 kb). In addition, blaTEM-52b was also found to be located on...... various other plasmids belonging to IncA/C and IncL/M, while blaTEM-52c was found on IncN-like as well as on IncR plasmids. In the majority of cases (n = 21) the blaTEM-52 gene was located on a Tn3 transposon. Seven out of 10 blaTEM-52 plasmids tested in conjugation experiments were shown to be capable of...

  15. Conservation of Salmonella typhimurium virulence plasmid maintenance regions among Salmonella serovars as a basis for plasmid curing.

    OpenAIRE

    Tinge, S A; Curtiss, R

    1990-01-01

    The association of large plasmids with virulence in invasive Salmonella serovars has led to a number of studies designed to uncover the role of these plasmids in virulence. This study addresses two aspects of virulence-associated plasmids. The first is the distribution of the replication and maintenance regions among the plasmids of different Salmonella serovars, and the second is the use of the conserved virulence plasmid par region to provide a rapid method for eliminating the virulence pla...

  16. High-throughput screening of cellulase F mutants from multiplexed plasmid sets using an automated plate assay on a functional proteomic robotic workcell

    OpenAIRE

    Qureshi Nasib; Bischoff Kenneth M; Li Xin-Liang; Riedmuller Steven B; Mertens Jeffrey A; Hughes Stephen R; Cotta Michael A; Farrelly Philip J

    2006-01-01

    Abstract Background The field of plasmid-based functional proteomics requires the rapid assay of proteins expressed from plasmid libraries. Automation is essential since large sets of mutant open reading frames are being cloned for evaluation. To date no integrated automated platform is available to carry out the entire process including production of plasmid libraries, expression of cloned genes, and functional testing of expressed proteins. Results We used a functional proteomic assay in a ...

  17. Plasmids of Xylella fastidiosa Mulberry-Infecting Strains Share Extensive Sequence Identity and Gene Complement with pVEIS01 From the Earthworm Symbiont Verminephrobacter Eiseniae

    Science.gov (United States)

    A ~25 kbp plasmid was present in each of four Californian strains of Xylella fastidiosa from mulberry affected with leaf scorch disease. Fragments of each plasmid were cloned into E. coli, sequenced, and assembled into circular contigs of 25,105 bp (pXF-RIV11 and pXF-RIV16) or 24,372 bp (pXF-RIV19 a...

  18. Factors affecting the relative competitiveness of cassava production in southwestern Trinidad

    OpenAIRE

    Patterson-Andrews, Hazel; Pemberton, Carlisle

    2010-01-01

    This study sought to determine the factors affecting the relative competitiveness (RC) measured as the normalized profit per acre, of cassava farmers in South Western Trinidad through a determination of the factors affecting the mean and variance of the RC inefficiency term of the farmers. A sample of 112 small farmers growing cassava as their main crop provided the data for the study. A normalized translog stochastic RC frontier model was estimated. The model also determined the factors affe...

  19. Effects of different replicons in conjugative plasmids on transformation efficiency, plasmid stability, gene expression and n-butanol biosynthesis in Clostridium tyrobutyricum

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Mingrui; Du, Yinming; Jiang, Wenyan; Chang, Wei-Lun; Yang, Shang-Tian [Ohio State Univ., Columbus, OH (United States). William G. Lowrie Dept. of Chemical and Biomolecular Engineering; Tang, I-Ching [Bioprocessing Innovative Company, Dublin, OH (United States)

    2012-01-15

    Clostridium tyrobutyricum ATCC 25755 can produce butyric acid, acetic acid, and hydrogen as the main products from various carbon sources. In this study, C. tyrobutyricum was used as a host to produce n-butanol by expressing adhE2 gene under the control of a native thiolase promoter using four different conjugative plasmids (pMTL82151, 83151, 84151, and 85151) each with a different replicon (pBP1 from C. botulinum NCTC2916, pCB102 from C. butyricum, pCD6 from Clostridium difficile, and pIM13 from Bacillus subtilis). The effects of different replicons on transformation efficiency, plasmid stability, adhE2 expression and aldehyde/alcohol dehydrogenase activities, and butanol production by different mutants of C. tyrobutyricum were investigated. Among the four plasmids and replicons studied, pMTL82151 with pBP1 gave the highest transformation efficiency, plasmid stability, gene expression, and butanol biosynthesis. Butanol production from various substrates, including glucose, xylose, mannose, and mannitol were then investigated with the best mutant strain harboring adhE2 in pMTL82151. A high butanol titer of 20.5 g/L with 0.33 g/g yield and 0.32 g/L h productivity was obtained with mannitol as the substrate in batch fermentation with pH controlled at {proportional_to}6.0. (orig.)

  20. How Multi-Tasking Job Designs Affect Productivity: Evidence from Australian Coal Mining Industry

    OpenAIRE

    Shingo Takahashi

    2011-01-01

    The author studies how the Australian coal mining industry adopted multitasking job designs by eliminating two types of task demarcations: (a) the demarcation between production and maintenance stream tasks and (b) the demarcation within the production stream. Using an original data set of Australian open-cut coal mines covering the period 1985-2005, he estimates the effect of multi-tasking on productivity and explains its effects. Results indicate that the elimination of between-demarcation ...

  1. Analyzing factors Affecting Consumers’ Attitude & Intention to Purchase Counterfeit products of luxury Brands In clothing Industry

    Directory of Open Access Journals (Sweden)

    Abdolhamid Ebrahimi

    2012-01-01

    Full Text Available One of the world trends growing alarmingly is Producing, distributing & Consuming counterfeit goods of Credible & luxury brands & one of the industries facing this crisis increasingly is clothing industry. Based on this, the present study aims to analyze & identify factors influencing Consumers’ attitude toward counterfeit products & intention to purchase such products in clothing industry that has been done in Sari, Mazandaran. And in it, these Factors effect on attitude toward counterfeit products & then the impact of attitude toward counterfeit products on intention to buy such products have been measured. The study method is a Survey type & in order to collect study data, a questionnaire designed with a combination of different available resources in literature has been used. To achieve the study goals, 384 individuals who purchased counterfeit products intentionally were chosen from Sari. To analyze data & test hypotheses, Study model & questionnaire, Cronbach's alpha coefficient tests, Structural Equations Modeling (SEM, Confirmatory Factorial Analysis (CFA & one-way Variance analysis (ANONA have been applied & two Software Packages SPSS & LISREL were used. Through reviewing the literature available & analyzing experts’ views, generally, 11 variables have been identified: Personal gratification, Value consciousness, Price–quality inference, Social Effect, Brand prestige, Brand Loyalty, Ethical Issues, Risk averseness, Subjective norm, perceived risk, Brand consciousness, as the influencing factors on attitude toward counterfeit products. Study Findings have indicated that the factors as Personal gratification, Value consciousness, Price–quality inference, Social Effect, Ethical Issues, Subjective norm, perceived risk, Brand consciousness, have meaningful effect on attitude to counterfeit products & the impact of Brand prestige, Brand Loyalty, Risk averseness, was not meaningfull on view about counterfeit products. Besides, the

  2. Analyzing factors Affecting Consumers’ Attitude & Intention to Purchase Counterfeit products of luxury Brands In clothing Industry

    Directory of Open Access Journals (Sweden)

    abdolhamid ebrahimi

    2012-12-01

    Full Text Available One of the world trends growing alarmingly is Producing, distributing & Consuming counterfeit goods of Credible & luxury brands & one of the industries facing this crisis increasingly is clothing industry. Based on this, the present study aims to analyze & identify factors influencing Consumers’ attitude toward counterfeit products & intention to purchase such products in clothing industry that has been done in Sari, Mazandaran. And in it, these Factors effect on attitude toward counterfeit products & then the impact of attitude toward counterfeit products on intention to buy such products have been measured. The study method is a Survey type & in order to collect study data, a questionnaire designed with a combination of different available resources in literature has been used. To achieve the study goals, 384 individuals who purchased counterfeit products intentionally were chosen from Sari. To analyze data & test hypotheses, Study model & questionnaire, Cronbach's alpha coefficient tests, Structural Equations Modeling (SEM, Confirmatory Factorial Analysis (CFA & one-way Variance analysis (ANONA have been applied & two Software Packages SPSS & LISREL were used. Through reviewing the literature available & analyzing experts’ views, generally, 11 variables have been identified: Personal gratification, Value consciousness, Price–quality inference, Social Effect, Brand prestige, Brand Loyalty, Ethical Issues, Risk averseness, Subjective norm, perceived risk, Brand consciousness, as the influencing factors on attitude toward counterfeit products. Study Findings have indicated that the factors as Personal gratification, Value consciousness, Price–quality inference, Social Effect, Ethical Issues, Subjective norm, perceived risk, Brand consciousness, have meaningful effect on attitude to counterfeit products & the impact of Brand prestige, Brand Loyalty, Risk averseness, was not meaningfull on view about counterfeit products. Besides, the

  3. Genetic, Physiological, and Environmental Factors Affecting Acrylamide Concentration in Fried Potato Products

    Science.gov (United States)

    The discovery of acrylamide in processed potato products has brought increased interest in the controlling Maillard reaction precursors (reducing sugars and amino acids) in potato tubers. Because of their effects on nonenzymatic browning of fried potato products, reducing sugars and amino acids have...

  4. Phenolic compounds affect production of pyocyanin, swarming motility and biofilm formation of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Aylin Ugurlu

    2016-08-01

    Conclusions: We may suggest that if swarming and consecutive biofilm formation could be inhibited by the natural products as shown in our study, the bacteria could not attach to the surfaces and produce chronic infections. Antimicrobials and natural products could be combined and the dosage of antimicrobials could be reduced to overcome antimicrobial resistance and drug side effects.

  5. Extrusion and Extruded Products: Changes in Quality Attributes as Affected by Extrusion Process Parameters: A Review.

    Science.gov (United States)

    Alam, M S; Kaur, Jasmeen; Khaira, Harjot; Gupta, Kalika

    2016-01-01

    Extrusion of foods is an emerging technology for the food industries to process and market a large number of products of varying size, shape, texture, and taste. Extrusion cooking technology has led to production of wide variety of products like pasta, breakfast cereals, bread crumbs, biscuits, crackers, croutons, baby foods, snack foods, confectionery items, chewing gum, texturized vegetable protein (TVP), modified starch, pet foods, dried soups, dry beverage mixes etc. The functional properties of extruded foods plays an important role for their acceptability which include water absorption, water solubility, oil absorption indexes, expansion index, bulk density and viscosity of the dough. The aim of this review is to give the detailed outlines about the potential of extrusion technology in development of different types of products and the role of extrusion-operating conditions and their effect on product development resulting in quality changes i.e physical, chemical, and nutritional, experienced during the extrusion process. PMID:25574813

  6. Does species richness affect fine root biomass and production in young forest plantations?

    DEFF Research Database (Denmark)

    Domisch, Timo; Finér, Leena; Dawud, Seid Muhie; Vesterdal, Lars; Raulund-Rasmussen, Karsten

    2015-01-01

    Tree species diversity has been reported to increase forest ecosystem above-ground biomass and productivity, but little is known about below-ground biomass and production in diverse mixed forests compared to single-species forests. For testing whether species richness increases below-ground biomass...... and production and thus complementarity between forest tree species in young stands, we determined fine root biomass and production of trees and ground vegetation in two experimental plantations representing gradients in tree species richness. Additionally, we measured tree fine root length and...... determined species composition from fine root biomass samples with the near-infrared reflectance spectroscopy method. We did not observe higher biomass or production in mixed stands compared to monocultures. Neither did we observe any differences in tree root length or fine root turnover. One reason for this...

  7. In vitro replication of mitochondrial plasmid mp1 from the higher plant Chenopodium album (L.): a remnant of bacterial rolling circle and conjugative plasmids?

    Science.gov (United States)

    Backert, S; Kunnimalaiyaan, M; Börner, T; Nielsen, B L

    1998-12-11

    According to the endosymbiotic theory, mitochondrial genomes evolved from the chromosome of an alpha-proteobacterium-like ancestor and developed during evolution an extraordinary variation in size, structure and replication. We studied in vitro DNA replication of the mitochondrial circular plasmid mp1 (1309 bp) from the higher plant Chenopodium album (L.) as a model system that replicates in a manner reminiscent of bacterial rolling circle plasmids. Several mp1 subclones were tested for their ability to support DNA replication using a newly developed in vitro system. Neutral/neutral two-dimensional gel electrophoresis of the in vitro products revealed typical simple Y patterns of intermediates consistent with a rolling circle type of replication. Replication activity was very high for a BamHI-restricted total plasmid DNA clone, a 464 bp BamHI/KpnI fragment and a 363 bp BamHI/SmaI fragment. Further subcloning of a 148 bp BamHI/EcoRI fragment resulted in the strongest in vitro DNA replication activity, while a 1161 bp-template outside of this region resulted in a substantial loss of activity. Electron microscopic studies of in vitro DNA replication products from the highly active clones also revealed sigma-shaped molecules. These results support our in vivo data for the presence of a predominant replication origin between positions 628 and 776 on the plasmid map. This sequence shares homology with double-stranded rolling circle origin (dso) or transfer origin (oriT) nicking motifs from bacterial plasmids. mp1 is the first described rolling circle plasmid in eukaryotes. PMID:9837722

  8. How can farming intensification affect the environmental impact of milk production?

    Science.gov (United States)

    Bava, L; Sandrucci, A; Zucali, M; Guerci, M; Tamburini, A

    2014-07-01

    The intensification process of the livestock sector has been characterized in recent decades by increasing output of product per hectare, increasing stocking rate, including more concentrated feed in the diet, and improving the genetic merit of the breeds. In dairy farming, the effects of intensification on the environmental impact of milk production are not completely clarified. The aim of the current study was to assess the environmental impacts of dairy production by a life cycle approach and to identify relations between farming intensity and environmental performances expressed on milk and land units. A group of 28 dairy farms located in northern Italy was involved in the study; data collected during personal interviews of farmers were analyzed to estimate emissions (global warming potential, acidification, and eutrophication potentials) and nonrenewable source consumption (energy and land use). The environmental impacts of milk production obtained from the life cycle assessment were similar to those of other recent studies and showed high variability among the farms. From a cluster analysis, 3 groups of farms were identified, characterized by different levels of production intensity. Clusters of farms showed similar environmental performances on product basis, despite important differences in terms of intensification level, management, and structural characteristics. Our study pointed out that, from a product perspective, the most environmentally friendly way to produce milk is not clearly identifiable. However, the principal component analysis showed that some characteristics related to farming intensification, such as milk production per cow, dairy efficiency, and stocking density, were negatively related to the impacts per kilogram of product, suggesting a role of these factors in the mitigation strategy of environmental burden of milk production on a global scale. Considering the environmental burden on a local perspective, the impacts per hectare were

  9. The Number of Loci That Affect Milk Production Traits in Dairy Cattle

    OpenAIRE

    Chamberlain, Amanda Jane; McPartlan, Helen Clare; Goddard, Michael Edward

    2007-01-01

    We have used the results of an experiment mapping quantitative trait loci (QTL) affecting milk yield and composition to estimate the total number of QTL affecting these traits. We did this by estimating the number of segregating QTL within a half-sib daughter design using logic similar to that used to estimate the “false discovery rate” (FDR). In a half-sib daughter design with six sire families we estimate that the average sire was heterozygous for ∼5 QTL per trait. Also, in most cases only ...

  10. BioShuttle-mediated Plasmid Transfer

    Directory of Open Access Journals (Sweden)

    Klaus Braun, Leonie von Brasch, Ruediger Pipkorn, Volker Ehemann, Juergen Jenne, Herbert Spring, Juergen Debus, Bernd Didinger, Werner Rittgen, Waldemar Waldeck

    2007-01-01

    Full Text Available An efficient gene transfer into target tissues and cells is needed for safe and effective treatment of genetic diseases like cancer. In this paper, we describe the development of a transport system and show its ability for transporting plasmids. This non-viral peptide-based BioShuttle-mediated transfer system consists of a nuclear localization address sequence realizing the delivery of the plasmid phNIS-IRES-EGFP coding for two independent reporter genes into nuclei of HeLa cells. The quantification of the transfer efficiency was achieved by measurements of the sodium iodide symporter activity. EGFP gene expression was measured with Confocal Laser Scanning Microscopy and quantified with biostatistical methods by analysis of the frequency of the amplitude distribution in the CLSM images. The results demonstrate that the “BioShuttle”-Technology is an appropriate tool for an effective transfer of genetic material carried by a plasmid.

  11. BioShuttle-mediated Plasmid Transfer

    Science.gov (United States)

    Braun, Klaus; von Brasch, Leonie; Pipkorn, Ruediger; Ehemann, Volker; Jenne, Juergen; Spring, Herbert; Debus, Juergen; Didinger, Bernd; Rittgen, Werner; Waldeck, Waldemar

    2007-01-01

    An efficient gene transfer into target tissues and cells is needed for safe and effective treatment of genetic diseases like cancer. In this paper, we describe the development of a transport system and show its ability for transporting plasmids. This non-viral peptide-based BioShuttle-mediated transfer system consists of a nuclear localization address sequence realizing the delivery of the plasmid phNIS-IRES-EGFP coding for two independent reporter genes into nuclei of HeLa cells. The quantification of the transfer efficiency was achieved by measurements of the sodium iodide symporter activity. EGFP gene expression was measured with Confocal Laser Scanning Microscopy and quantified with biostatistical methods by analysis of the frequency of the amplitude distribution in the CLSM images. The results demonstrate that the “BioShuttle”-Technology is an appropriate tool for an effective transfer of genetic material carried by a plasmid. PMID:18026568

  12. Upgrading of citric acid production from cheap carbohydrate sources as affected by aspergillus

    International Nuclear Information System (INIS)

    Five strains of aspergillus niger (EMCC 102, EMCC 104, EMCC 111, EMCC 132 and EMCC 147) were for citric acid production at different incubation period using different cheap carbohydrate substrates, such as beet, cane and citrus molasses and milk whey. A. niger EMCC 111 was found to be the most potent strain for citric acid production from beet molasses after 11 days of incubation at 30 degree. The studies concerning molasses concentration and nitrogen sources (inorganic and organic sources with different concentration, revealed that 30 g% beet molasses and ammonium sulfate with 0.05 g% as N2 content, gave the highest production of citric acid. Gamma irradiated inocula of A. niger EMCC 111 at doses (0.05-0.8 KGy), showed that the dose 0.4 KGy was the optimum for maximum citric acid production. 8 tabs

  13. Production and characterization of chicken origin Shigella dysenteriae ghosts with double bacteriolysis plasmids%双重溶菌质粒制备鸡痢疾志贺菌菌壳的研究

    Institute of Scientific and Technical Information of China (English)

    蒋大伟; 刘军; 张瑞安; 夏力亮; 孙洋; 祝令伟; 冯书章; 许兰菊

    2013-01-01

    In order to improve lysis rate and stability of chicken origin Shigella dysenteriae ghosts,recombinant strain of Shigella with double bacteriolytic plasmids was constructed and its characteristics was studied. Two recombinant bacteriolysis plasmid pBV220: :E and pBBR IMCS-E were co-transformed into the Shigella strain isolated from chicken to produce recombinant strain Sd(pBV220::E /pBBRIMCS-E). The recombinant strain Sd(pBV220::E /pBBRIMCS-E) was grown at 28℃ with shaking until mid log-phase,followed by incubation at 42℃ to induce the expression of gene E and produce Shigella dysenteriae ghosts. The D600 value of bacterial cultures was monitored over 20 h at 30 min intervals. The morphology of chicken origin Shigella dysenteriae ghosts was observed by electron microscope. The recombinant strains Sd(pBV220 : : E/pB-BRIMCS-E) generated chicken origin Shigella dysenteriae ghosts after inducing at 42℃. The ghosts retained basic cell morphology,with the lysis rate of 99. 999 9%. The chicken origin Shigella dysenteriae ghosts were generated successfully with double bacteriolysis plasmids, which laid foundation for future development of bacterial ghost vaccine against Shigella infection in chicken.%通过将2种不同的重组溶菌质粒转化至鸡痢疾志贺菌中,构建含有双重溶菌质粒的志贺菌重组菌株,以提高该菌菌壳制备的裂解率和稳定性,并对其特性进行研究.用重组溶菌质粒pBV220::E和pBBRIMCS-E共同转化到鸡痢疾志贺菌,构建志贺菌重组菌株Sd(pBV220::E/pBBRI MCS-E),重组菌株于28 C培养至D600值为0.5时升至42℃继续培养,间隔30 min检测菌液D600值,进行重组菌株的溶菌裂解动力学比较试验,绘制裂解曲线图并计算出裂解率,制备菌壳并对其形态进行电镜观察.重组菌株Sd(pBV220::E/pBBRIMCS-E)经42℃诱导后可形成菌壳且保留了基本的细胞形态,裂解率达到了99.999 9%.本研究成功制备出鸡痢疾志贺菌菌壳,为研究利用该

  14. Dirhinus giffardii (Hymenoptera: Chalcididae), parasitoid affecting Black Soldier Fly production systems in West Africa

    OpenAIRE

    Emilie Devic; Pierre-Olivier Maquart

    2015-01-01

    Interest for insect farming is currently growing globally. Conditions in West Africa appear suitable for developing such farming systems that can benefit communities by improving livelihoods, food and feed security or sanitation. In Ghana and Mali, the Black Soldier Fly (Hermetia illucens Linnaeus, 1758) is being produced for waste recycling and animal feed. In a two stages process (egg and larvae production), egg production was hampered by a pupal parasitoid, Dirhinus giffardii Silvestri, 19...

  15. How will conversion to organic cereal production affect carbon stocks in Swedish agricultural soils?

    OpenAIRE

    Andrén, Olof; Kätterer, Thomas; Kirchmann, Holger

    2008-01-01

    Soil carbon changes were modelled over 30 years with the focus on cereal crops, since leys are often managed similarly in organic and conventional agriculture. Other crops were not considered due to difficulties in large-scale cropping of oilseed rape and potatoes organically because of pest problems. Four scenarios were used: 0%, 8% (current), 20% and 100% organic cereal production. Conversion to organic cereal crop production was found to reduce the amount of carbon stored as organic matter...

  16. The Inventive, the Educated, and the Creative: How Do They Affect Metropolitan Productivity?

    OpenAIRE

    Lobo, José; Mellander, Charlotta; Stolarick, Kevin; Strumsky, Deborah

    2012-01-01

    A longstanding research tradition assumes that endogenous technological development increases regional productivity. It has been assumed that measures of regional patenting activity or human capital are an adequate way to capture the endogenous creation of new ideas that result in productivity improvements. This process has been conceived as occurring in two stages. First, an invention or innovation is generated, and then it is developed and commercialized to create benefits for the individua...

  17. Analyzing factors Affecting Consumers’ Attitude & Intention to Purchase Counterfeit products of luxury Brands In clothing Industry

    OpenAIRE

    abdolhamid ebrahimi; mehdi jafarzadeh; saber bozorgi

    2012-01-01

    One of the world trends growing alarmingly is Producing, distributing & Consuming counterfeit goods of Credible & luxury brands & one of the industries facing this crisis increasingly is clothing industry. Based on this, the present study aims to analyze & identify factors influencing Consumers’ attitude toward counterfeit products & intention to purchase such products in clothing industry that has been done in Sari, Mazandaran. And in it, these Factors effect on attitude toward counterfeit p...

  18. Counterfeiters: Foes or Friends? How Do Counterfeits Affect Different Product Quality Tiers?

    OpenAIRE

    Yi Qian

    2011-01-01

    A key concern about counterfeits and weak intellectual property protection is that they may hamper innovation by displacing legitimate sales. This paper combines a natural policy experiment with randomized lab experiments to estimate the heterogeneous impacts of counterfeiting on the sales and consumer purchase intent related to branded products of various quality levels. I collect new product-line-level panel data (1993-2004) on Chinese shoe companies. I identify heterogeneous effects of cou...

  19. Corn Production as Affected by Phosphorus Enhancers, Phosphorus Source and Lime

    OpenAIRE

    Christopher J. Dudenhoeffer; Kelly A. Nelson; Motavalli, Peter P.; David Dunn; Stevens, William E.; Goyne, Keith W.; Manjula Nathan; Peter Scharf

    2012-01-01

    Prompted by high cost of fertilizer, farmers are investigating ways to enhance the efficiency of phosphorus (P) fertilizers. This study examined the effects of liming application (0 Mg ha-1 and recommended rate), P source [non-treated control and a broadcast application of diammonium phosphate (DAP) or triple superphosphate (TSP)], and the presence or absence of two commercial enhanced efficiency P products (Avail? and P2O5-Max?) on corn (Zea mays L.) production. The study was conducted at No...

  20. Optimization of key factors affecting hydrogen production from sugarcane bagasse by a thermophilic anaerobic pure culture

    OpenAIRE

    Lai, Zhicheng; Zhu, Muzi; Yang, Xiaofeng; Wang, JuFang; Li, Shuang

    2014-01-01

    Background Hydrogen is regarded as an attractive future energy carrier for its high energy content and zero CO2 emission. Currently, the majority of hydrogen is generated from fossil fuels. However, from an environmental perspective, sustainable hydrogen production from low-cost lignocellulosic biomass should be considered. Thermophilic hydrogen production is attractive, since it can potentially convert a variety of biomass-based substrates into hydrogen at high yields. Results Sugarcane baga...

  1. BioShuttle-mediated Plasmid Transfer

    OpenAIRE

    Braun, Klaus; von Brasch, Leonie; Pipkorn, Ruediger; Ehemann, Volker; Jenne, Juergen; Spring, Herbert; Debus, Juergen; Didinger, Bernd; Rittgen, Werner; Waldeck, Waldemar

    2007-01-01

    An efficient gene transfer into target tissues and cells is needed for safe and effective treatment of genetic diseases like cancer. In this paper, we describe the development of a transport system and show its ability for transporting plasmids. This non-viral peptide-based BioShuttle-mediated transfer system consists of a nuclear localization address sequence realizing the delivery of the plasmid phNIS-IRES-EGFP coding for two independent reporter genes into nuclei of HeLa cells. The quantif...

  2. Nonselective Persistence of a Rickettsia conorii Extrachromosomal Plasmid during Mammalian Infection.

    Science.gov (United States)

    Riley, Sean P; Fish, Abigail I; Garza, Daniel A; Banajee, Kaikhushroo H; Harris, Emma K; del Piero, Fabio; Martinez, Juan J

    2016-03-01

    Scientific analysis of the genus Rickettsia is undergoing a rapid period of change with the emergence of viable genetic tools. The development of these tools for the mutagenesis of pathogenic bacteria will permit forward genetic analysis of Rickettsia pathogenesis. Despite these advances, uncertainty still remains regarding the use of plasmids to study these bacteria in in vivo mammalian models of infection, namely, the potential for virulence changes associated with the presence of extrachromosomal DNA and nonselective persistence of plasmids in mammalian models of infection. Here, we describe the transformation of Rickettsia conorii Malish 7 with the plasmid pRam18dRGA[AmTrCh]. Transformed R. conorii stably maintains this plasmid in infected cell cultures, expresses the encoded fluorescent proteins, and exhibits growth kinetics in cell culture similar to those of nontransformed R. conorii. Using a well-established murine model of fatal Mediterranean spotted fever, we demonstrate that R. conorii(pRam18dRGA[AmTrCh]) elicits the same fatal outcomes in animals as its untransformed counterpart and, importantly, maintains the plasmid throughout infection in the absence of selective antibiotic pressure. Interestingly, plasmid-transformed R. conorii was readily observed both in endothelial cells and within circulating leukocytes. Together, our data demonstrate that the presence of an extrachromosomal DNA element in a pathogenic rickettsial species does not affect either in vitro proliferation or in vivo infectivity in models of disease and that plasmids such as pRam18dRGA[AmTrCh] are valuable tools for the further genetic manipulation of pathogenic rickettsiae. PMID:26755154

  3. DID THE 2004 CAP REFORM AFFECT PRODUCTION PRACTICES OF CEREALS? INSIGHTS FROM THE AGRICULTURAL INPUT SUPPLIERS

    Directory of Open Access Journals (Sweden)

    Theodoros MARKOPOULOS

    2015-10-01

    Full Text Available The Mid-term review of the Common Agricultural Policy in 2003/2004 has strengthened the multifunctional role of agriculture by implementing “decoupling”, “modulation” and “cross-compliance” and created a number of significant changes in agricultural production in all EU member states. Specifically, the reform shifted emphasis away from commodity support towards environmental contracts, diversified production practices and rural development. In the case of cereals, a full decoupling was applied in subsidies and integration through rights in the Single Payment Scheme, except rice, which was one of the few crop cases in which part of the subsidy remained coupled, particular in countries with significant production like Greece. Within this context, the present study aims to analyze the impact that the reformed CAP measures had on agricultural production and more specifically variations in production diversification. The novelty of this study is that instead of focusing on the producers, it targeted the agricultural input stores, so as to get better insights of the CAP reform impacts on a larger scale of the regional economy. Accordingly, primary data were collected through personal interviews (structured questionnaire from 209 owners of agricultural input stores in the region of Anatoliki Makedonia and Thraki and were analyzed through multivariate data analysis. The results identify important antecedents for the regional economy and the viability of agricultural input stores, which include factors of the reformed CAP, environmental issues, financial measures and CAP effects on cereal production and marketing.

  4. Effect of ionizing radition on conjugative R plasmid in Escherichia coli

    International Nuclear Information System (INIS)

    Five-fold cyclic gamma irradiation of E. coli strain No. 214 with conjugative R plasmid with doses of 150 Gy, with the exception of chloramphenicol, did not essentially affect the expression of the examined determinants of resistance to antimicrobial substances (tetracycline, streptomycin, chloramphenicol, canamycin, ampicillin, sulfamethoxidine). The dose of 150 Gy from the first irradiation of the strain reduced the transfer frequency of the R plasmid approximately hundred-fold. After the second up to the fourth irradiation of the strain the transfer frequency went back to approximately its original value. (author)

  5. Characterization of Tn904 insertions in octopine Ti plasmid mutants of Agrobacterium tumefaciens.

    OpenAIRE

    Ooms, G.; Klapwijk, P M; Poulis, J A; Schilperoort, R A

    1980-01-01

    Seven Tn904 insertion mutants of pTi Ach5 affecting Agrobacterium tumefaciens virulence were studied. The mutant character was shown to be plasmid borne. Four of these mutants were avirulent and carried an insertion in restriction endonuclease HpaI fragment 12, a 3.3-megadalton fragment, which therefore appears to be a Ti plasmid region essential for virulence. Two mutants were attenuated in virulence. The inserts mapped close to HpaI fragment 12. One mutant giving rise to small tumors with e...

  6. Reactive oxygen species controllable non-thermal helium plasmas for evaluation of plasmid DNA strand breaks

    Science.gov (United States)

    Young Kim, Jae; Lee, Dong-Hoon; Ballato, John; Cao, Weiguo; Kim, Sung-O.

    2012-11-01

    Non-thermal, oxygen-rich helium plasmas were investigated to achieve an enhanced reactive oxygen species concentration at low voltage driving conditions. A non-thermal plasma device was fabricated based on a theta-shaped tube, and its potential was investigated for use in topological alteration of plasmid DNA. The optical emission spectra of the plasma showed that the oxygen flow affected the plasma properties, even though an oxygen plasma was not produced. The plasmid DNA strand breaks became more significant with the addition of oxygen flow to the helium in a single hollow, theta-shaped tube with other experimental conditions being unchanged.

  7. Construction of a recombinant plasmid pSH-G containing the rabies-virus glycoprotein G gene

    OpenAIRE

    P. Carnieli JR; A. M. Ventura; Durigon, E L

    2007-01-01

    A plasmid named pSH-G was constructed with the rabies-virus G-gene insert. This plasmid was transfected into eukaryotic BHK-21 cells and its stability tested. The presence of the pSH-G plasmid was confirmed by means of polymerase chain reaction (PCR) after each of ten cell passages, and the results were positive. The stable BHK-21/pSH-G+ clone obtained can be used in the study of rabies as well as in the production of vaccines.

  8. Construction of a recombinant plasmid pSH-G containing the rabies-virus glycoprotein G gene

    Directory of Open Access Journals (Sweden)

    P. Carnieli JR

    2007-01-01

    Full Text Available A plasmid named pSH-G was constructed with the rabies-virus G-gene insert. This plasmid was transfected into eukaryotic BHK-21 cells and its stability tested. The presence of the pSH-G plasmid was confirmed by means of polymerase chain reaction (PCR after each of ten cell passages, and the results were positive. The stable BHK-21/pSH-G+ clone obtained can be used in the study of rabies as well as in the production of vaccines.

  9. A Comparison of the Growth Responses Following Intramuscular GHRH Plasmid Administration Versus Daily Growth Hormone Injections in Young Pigs

    OpenAIRE

    Khan, Amir S.; Draghia-Akli, Ruxandra; Shypailo, Roman J; Ellis, Kenneth I; Mersmann, Harry; Fiorotto, Marta L.

    2009-01-01

    The efficacy of daily porcine growth hormone (GH) injections versus plasmid-driven porcine GH-releasing hormone (pGHRH) production to promote growth was assessed. Ten-day-old piglets were injected intramuscularly with 0.1, 1, or 3 mg pGHRH, or a control plasmid followed by electroporation. Plasmid constructs were driven by a synthetic muscle-specific promoter. A fifth group received daily injections of GH [0.15 mg/(kg·day)]. Control and pGHRH-treated pigs were pair-fed to GH-treated pigs. Bod...

  10. Competition between Plasmid-Bearing and Plasmid-Free Organisms in a Chemostat with Pulsed Input and Washout

    Directory of Open Access Journals (Sweden)

    Sanling Yuan

    2009-01-01

    Full Text Available We consider a model of competition between plasmid-bearing and plasmid-free organisms in the chemostat with pulsed input and washout. We investigate the subsystem with nutrient and plasmid-free organism and study the stability of the boundary periodic solutions, which are the boundary periodic solutions of the system. The stability analysis of the boundary periodic solution yields the invasion threshold of the plasmid-bearing organism. By using the standard techniques of bifurcation theory, we prove that above this threshold there are periodic oscillations in substrate, plasmid-free, and plasmid-bearing organisms. Numerical simulations are carried out to illustrate our results.

  11. Plasmid maintenance functions of the large virulence plasmid of Shigella flexneri.

    OpenAIRE

    Radnedge, L; Davis, M. A.; Youngren, B; Austin, S. J.

    1997-01-01

    The large virulence plasmid pMYSH6000 of Shigella flexneri contains a replicon and a plasmid maintenance stability determinant (Stb) on adjacent SalI fragments. The presence of a RepFIIA replicon on the SalI C fragment was confirmed, and the complete sequence of the adjacent SalI O fragment was determined. It shows homology to part of the transfer (tra) operon of the F plasmid. Stb stabilizes a partition-defective P1 miniplasmid in Escherichia coli. A 1.1-kb region containing a homolog of the...

  12. Plasmid transfer and plasmid-mediated genetic exchange in Brucella abortus.

    OpenAIRE

    Rigby, C E; Fraser, A.D.

    1989-01-01

    Naturally-occurring plasmids and gene transfer mechanisms have not yet been reported in brucellae. Here we show that Brucella abortus is capable of maintaining and transferring the broad-host-range plasmids pTH10 (IncP), pSa (IncW) and R751 (IncP), and describe pTH10-mediated transfer of B. abortus chromosomal genes to Escherichia coli. All three plasmids transferred by conjugation from E. coli to B. abortus S19, and from B. abortus S19 to B. abortus 292 (biovar 4). They were stably maintaine...

  13. Plasmid transduction by Bacillus subtilis bacteriophage SPP1: effects of DNA homology between plasmid and bacteriophage.

    OpenAIRE

    Deichelbohrer, I; Alonso, J.C.; Lüder, G; Trautner, T A

    1985-01-01

    Any SPP1 DNA restriction fragment cloned into Bacillus subtilis plasmid pC194 or pUB110 increased the transduction frequency of the plasmid by SPP1 100- to 1,000-fold over the transduction level of the plasmid alone. This increment was observed irrespective of whether a fragment contained the SPP1 packaging origin (pac). Furthermore, an SPP1 derivative into whose genome pC194 DNA had been integrated transduced pC194 DNA with a greatly enhanced frequency. Transduction enhancement mediated by D...

  14. Productive love promotion via affective technology : An approach based on social psychology and philosophy

    OpenAIRE

    Ramon Solves Pujol; Hiroyuki Umemuro

    2010-01-01

    A recent development in the technology acceptance literature is the inclusion of gender as a moderator of the relationships between intention and its antecedents, such that some are stronger for men than women, and vice versa. While the effects have been well established, the mechanisms by which they operate, that is, which specific gender differences are in operation and how they affect intention to adopt, have not been thoroughly explored. In this research, psychological cons...

  15. How does increased corn-ethanol production affect US natural gas prices?

    International Nuclear Information System (INIS)

    In recent years, there has been a push to increase biofuel production in the United States. The biofuel of choice, so far, has been ethanol produced from corn. The effects of increased corn-ethanol production on the consumer prices of food and energy continue to be studied and debated. This study examines, in particular, the effects of increased corn-ethanol production on US natural gas prices. A structural model of the natural gas market is developed and estimated using two stage least squares. A baseline projection for the period 2007-2018 is determined, and two scenarios are simulated. In the first scenario, current biofuel policies including EISA mandates, tariffs, and tax credits are removed. In the second scenario, we hold ethanol production to the level required only for largely obligatory additive use. The results indicate that the increased level of corn-ethanol production occurring as a result of the current US biofuel policies may lead to natural gas prices that are as much as 0.25% higher, on average, than if no biofuel policies were in place. A similar comparison between the baseline and second scenario indicates natural gas prices could be as much as 0.5% higher, on average, for the same period. (author)

  16. How does increased corn-ethanol production affect US natural gas prices?

    International Nuclear Information System (INIS)

    In recent years, there has been a push to increase biofuel production in the United States. The biofuel of choice, so far, has been ethanol produced from corn. The effects of increased corn-ethanol production on the consumer prices of food and energy continue to be studied and debated. This study examines, in particular, the effects of increased corn-ethanol production on US natural gas prices. A structural model of the natural gas market is developed and estimated using two stage least squares. A baseline projection for the period 2007-2018 is determined, and two scenarios are simulated. In the first scenario, current biofuel policies including EISA mandates, tariffs, and tax credits are removed. In the second scenario, we hold ethanol production to the level required only for largely obligatory additive use. The results indicate that the increased level of corn-ethanol production occurring as a result of the current US biofuel policies may lead to natural gas prices that are as much as 0.25% higher, on average, than if no biofuel policies were in place. A similar comparison between the baseline and second scenario indicates natural gas prices could be as much as 0.5% higher, on average, for the same period.

  17. Analysis of the Factors Affecting Consumer’s Some Traditional Food Products Preferences by Multidimensional Scaling Method

    OpenAIRE

    Y. Oraman G. Unakıtan E. Yılmaz B. Başaran

    2011-01-01

    The aim of this study is to evaluate consumer behaviour towards factors affecting purchase decision of some traditional food products and grouping those consumer attitudes. The original data was obtained from results of a survey conducted in 14 different districts in Tekirdag. The survey consisted of face-to-face interviews conducted within a total sample of 166 households randomly. In the study, multidimensional scaling analysis is used for evaluating the effective factors of consumer prefer...

  18. Evaluation of factors affecting cucumber- and- tomato greenhouse farmers\\\\\\' attitudes toward healthy crops production in Isfahan Township

    OpenAIRE

    A. Sandoghi; Yousefi, A.; A.M AMINI

    2015-01-01

    The aim of this study was to evaluate the factors affecting the attitude of cucumber and tomato greenhouse farmers toward production of healthy crops in Isfahan County. Data were collected on a sample of 110 farmers through face-to-face interviews based on a comprehensive structured questionnaire. Validity and reliability of the questionnaire was initially evaluated on a pre-test study respectively by using Kaiser-Meyer-Olkin (KMO) criteria and Cronbach’s alpha coefficient. Factors influencin...

  19. Detection of genetic variants affecting cattle behaviour and their impact on milk production: a genome-wide association study.

    Science.gov (United States)

    Friedrich, Juliane; Brand, Bodo; Ponsuksili, Siriluck; Graunke, Katharina L; Langbein, Jan; Knaust, Jacqueline; Kühn, Christa; Schwerin, Manfred

    2016-02-01

    Behaviour traits of cattle have been reported to affect important production traits, such as meat quality and milk performance as well as reproduction and health. Genetic predisposition is, together with environmental stimuli, undoubtedly involved in the development of behaviour phenotypes. Underlying molecular mechanisms affecting behaviour in general and behaviour and productions traits in particular still have to be studied in detail. Therefore, we performed a genome-wide association study in an F2 Charolais × German Holstein cross-breed population to identify genetic variants that affect behaviour-related traits assessed in an open-field and novel-object test and analysed their putative impact on milk performance. Of 37,201 tested single nucleotide polymorphism (SNPs), four showed a genome-wide and 37 a chromosome-wide significant association with behaviour traits assessed in both tests. Nine of the SNPs that were associated with behaviour traits likewise showed a nominal significant association with milk performance traits. On chromosomes 14 and 29, six SNPs were identified to be associated with exploratory behaviour and inactivity during the novel-object test as well as with milk yield traits. Least squares means for behaviour and milk performance traits for these SNPs revealed that genotypes associated with higher inactivity and less exploratory behaviour promote higher milk yields. Whether these results are due to molecular mechanisms simultaneously affecting behaviour and milk performance or due to a behaviour predisposition, which causes indirect effects on milk performance by influencing individual reactivity, needs further investigation. PMID:26515756

  20. Dirhinus giffardii (Hymenoptera: Chalcididae, parasitoid affecting Black Soldier Fly production systems in West Africa

    Directory of Open Access Journals (Sweden)

    Emilie Devic

    2015-12-01

    Full Text Available Interest for insect farming is currently growing globally. Conditions in West Africa appear suitable for developing such farming systems that can benefit communities by improving livelihoods, food and feed security or sanitation. In Ghana and Mali, the Black Soldier Fly (Hermetia illucens Linnaeus, 1758 is being produced for waste recycling and animal feed. In a two stages process (egg and larvae production, egg production was hampered by a pupal parasitoid, Dirhinus giffardii Silvestri, 1913 (Hymenoptera: Chalcididae, which reduced future broodstock by almost 72%. This is the first time D. giffardii is reported as a parasitoid of H. illucens pupae and one of the first reports of parasitism in this commercially important fly species. The introduction of precautionary measures is highly recommended for the success of H. illucens production systems in West Africa.

  1. PREDICTING OF THE FACTORS AFFECTING CONSUMER BEHAVIOR THE CHOICE OF ORGANIC PRODUCTS BY LOGIT REGRESSION ANALYSIS

    Directory of Open Access Journals (Sweden)

    Selma KARABAŞ

    2012-06-01

    Full Text Available The purpose of this study is to determine consumer behavior towards organic products in Samsun city center and to determine the factors affacting their preferences of organic products. The study was interviewed with 478 consumers living the city center of Samsun. According of the findings, ease of accesibility of organic products, spouse’s educational level, paying extra for the organic produce, aware of food health benefits, considering the harmful effects of conventional produce, having complete knowledge of organic farming and one unit increase household number income to result increase consumption of organic produce. Consumers were not aware of the certification and control process. As a result, easy of accesibility of organic produces in the supermarkets need to be improved.

  2. Process parameters affecting the sustainability of fermentative hydrogen production: A short-review

    Directory of Open Access Journals (Sweden)

    Carlos Dinamarca, Rune Bakke

    2011-11-01

    Full Text Available Anaerobic fermentation is regarded as the least energy intensive method for H2 production. Extensive literature on experimental attempts to achieve the highest possible theoretical yield (e.g. 4 mol H2/mol glucose is available. All published steady state, mixed culture studies show yields much lower than the theoretical maximums for the substrates applied. This article summarizes the influence of key process parameters (pH and buffer systems, temperature, H2 partial pressure, feed stock, and reactor configuration on fermentative hydrogen production. The following three requirements for successful Bio-H2 fermentation in mixed cultures are identified: (1 Maintain environmental conditions for the formation of oxidized products; (2 Optimize the relationship between biomass and hydrogen yields; and (3 Maintain unfavorable conditions for hydrogen consuming organisms. Fulfilling these requirements has not yet been achieved in stable continuous cultures, and it may not be achievable do to some fundamental limitation.

  3. Mixed populations of marine microalgae in continuous culture: Factors affecting species dominance and biomass productivity.

    Science.gov (United States)

    Regan, D L; Ivancic, N

    1984-11-01

    Marine microalgae were grown in multispecies continuous cultures. Under carbon dioxide limitation, blue-green algae dominated. Under nitrate and light limitation, species dominance depended on the initial conditions. When the inoculum consisted primarily of blue-green algae with smaller amounts of other species, blue-green algae and pennate diatoms dominated. When the inoculum consisted of equal amounts of all species, green flagellates and pennate diatoms dominated. Green flagellates and blue-green algae were incompatible and never shared dominance. When nutrient limitations were overcome, the productivity of seawater was increased 100-fold before light limitation occurred. The productivity could be further increased by reducing photorespiration in the culture. The dilution rates studied (0.1, 0.2, and 0.4 day(-1)) had no effect on species dominance, nor did the higher dilution rates select for smaller cells. The maximum productivity occurred at a dilution rate of 0.2 day(-1). Temperature had the greatest effect on species dominance, with green flagellates, pennate diatoms, and blue-green algae dominating at 20 degrees C and only blue-green algae dominating at 35 degrees C. The productivity at 35 degrees C was lower than that at 20 degrees C because of the lower solubility of carbon dioxide at higher temperatures. At 10% salinity, green flagellates and pennate diatoms dominated. The productivity at this salinity was 50% that obtained at the salinity of seawater (3.5%). At 25% salinity, only the green flagellate, Dunaliella salina, survived at a productivity of 1% that obtained at the salinity of seawater. PMID:18551649

  4. Biological short-chain fatty acids (SCFAs) production from waste-activated sludge affected by surfactant.

    Science.gov (United States)

    Jiang, Su; Chen, Yinguang; Zhou, Qi; Gu, Guowei

    2007-07-01

    Short-chain fatty acids (SCFAs), the preferred carbon sources for biological nutrient removal, are the important intermediate products in sludge anaerobic fermentation. Sodium dodecylbenzene sulfonate (SDBS) is a widespread used surfactant, which can be easily found in waste-activated sludge (WAS). In this investigation, the effect of SDBS on SCFAs production from WAS was investigated, and the potential of using fermentative SCFAs to promote enhanced biological phosphorus removal (EBPR) was tested. Results showed that the total SCFAs production increased significantly in the presence of SDBS at room temperature. At fermentation time of 6 days, the maximum SCFAs was 2599.1mg chemical oxygen demand (COD)/L in the presence of SDBS 0.02g/g, whereas it was only 339.1mg (COD)/L in the absence of SDBS. The SCFAs produced in the case of SDBS 0.02g/g and fermentation time 6 days consisted of acetic acid (27.1%), propionic acid (22.8%), iso-valeric acid (20.1%), iso-butyric acid (11.9%), n-butyric acid (10.4%) and n-valeric acid (7.7%). It was found that during sludge anaerobic fermentation, the solubilization of sludge particulate organic-carbon and hydrolysis of solubilized substrate as well as acidification of hydrolyzed products were all increased in the presence of SDBS, while the methane formation was decreased, the SCFAs production was therefore remarkably improved. Further investigation showed that the production of SCFAs enhanced by SDBS was caused mainly by biological effects, rather than by chemical effects and SDBS decomposition. With the fermentative SCFAs as the main carbon source, the EBPR maintained high phosphorus removal efficiency ( approximately 97%). PMID:17499838

  5. Cheese liking and consumer willingness to pay as affected by information about organic production.

    Science.gov (United States)

    Napolitano, Fabio; Braghieri, Ada; Piasentier, Edi; Favotto, Saida; Naspetti, Simona; Zanoli, Raffaele

    2010-08-01

    The present study aimed to assess the effect of information about organic production on Pecorino cheese liking and consumer willingness to pay. Mean scores of perceived liking were similar for organic cheese (OC) and conventional cheese (CC). Expected liking scores were higher for OC than for CC (Pconventional (1.90 euro/100 g) and even organic cheese (3.00 euro/100 g). We conclude that the information about organic farming can be a major determinant of cheese liking and consumer willingness to pay, thus providing a potential tool for product differentiation, particularly for small scale and traditional farms. PMID:20196900

  6. Compost amendment of sandy soil affects soil properties and greenhouse tomato productivity

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Cornelis, W.; Razzaghi, Fatemeh

    2012-01-01

    Sandy soils, with low productivity, could be improved by compost application to sustain crop production. This study aimed to examine the effect of three compost types (vegetable, fruit and yard waste compost, garden waste compost, and spent mushroom compost) on basic properties of a loamy sand...... and significantly decreased bulk density, with no effect on plant available water compared to the control. Fresh and dry fruit weights were significantly increased after compost addition. Plant height, leaf number, stem diameter, and total biomass did not significantly improve after compost addition. Spent mushroom...

  7. Engaged or exhausted—How does it affect dentists’ clinical productivity?

    Directory of Open Access Journals (Sweden)

    Jari J. Hakanen

    2014-06-01

    Full Text Available This cross-sectional study examines whether job burnout (exhaustion and work engagement are associated with the clinical productivity of dentists measured by the amount of paid procedure fees in a single month. We conducted an OLS regression analyses of data on dentists working at municipal health centers in Finland (N = 269; response rate 37%. The results indicated that work engagement was positively associated with the amount of procedure fees and consequently with dentists’ pay level after several work-related and demographic background variables were controlled for. However, exhaustion was not related to productivity after controlling for the impact of other factors.

  8. Bioaugmentation of DDT-contaminated soil by dissemination of the catabolic plasmid pDOD

    Institute of Scientific and Technical Information of China (English)

    Chunming Gao; Xiangxiang Jin; Jingbei Ren; Hua Fang; Yunlong Yu

    2015-01-01

    A plasmid transfer-mediated bioaugmentation method for the enhancement of dichlorodiphenyltrichloroethane (DDT) degradation in soil was developed using the catabolic plasmid pDOD from Sphingobacterium sp.D-6.The pDOD plasmid could be transferred to soil bacteria,such as members of Cellulomonas,to form DDT degraders and thus accelerate DDT degradation.The transfer efficiency of pDOD was affected by the donor,temperature,moisture,and soil type.Approximately 50.7% of the DDT in the contaminated field was removed 210 days after the application of Escherichia coli TG Ⅰ (pDOD-gfp).The results suggested that seeding pDOD into soil is an effective bioaugmentation method for enhancing the degradation of DDT.

  9. Effect of degradative plasmid CAM-OCT on responses of Pseudomonas bacteria to UV light

    International Nuclear Information System (INIS)

    The effect of plasmid CAM-OCT on responses to UV irradiation was compared in Pseudomonas aeruginosa, in Pseudomonas putida, and in Pseudomonas putida mutants carrying mutations in UV response genes. CAM-OCT substantially increased both survival and mutagenesis in the two species. P. aeruginosa strains without CAM-OCT exhibited much higher UV sensitivity than did P. putida strains. UV-induced mutagenesis of plasmid-free P. putida was easily detected in three different assays (two reversion assays and one forward mutation assay), whereas UV mutagenesis of P. aeruginosa without CAM-OCT was seen only in the forward mutation assay. These results suggest major differences in DNA repair between the two species and highlight the presence of error-prone repair functions on CAM-OCT. A number of P. putida mutants carrying chromosomal mutations affecting either survival or mutagenesis after UV irradiation were isolated, and the effect of CAM-OCT on these mutants was determined. All mutations producing a UV-sensitive phenotype in P. putida were fully suppressed by the plasmid, whereas the plasmid had a more variable effect on mutagenesis mutations, suppressing some and producing no suppression of others. On the basis of the results reported here and results obtained by others with plasmids carrying UV response genes, it appears that CAM-OCT may differ either in regulation or in the number and functions of UV response genes encoded

  10. Chromosomal genes essential for stable maintenance of the mini-F plasmid in Escherichia coli.

    Science.gov (United States)

    Niki, H; Ichinose, C; Ogura, T; Mori, H; Morita, M; Hasegawa, M; Kusukawa, N; Hiraga, S

    1988-01-01

    We have isolated mutants of Escherichia coli which do not support stable maintenance of mini-F plasmids (delta ccd rep+ sop+). These host mutations, named hop, were classified into five linkage groups on the E. coli chromosome. Genetic analyses of these hop mutations by Hfr mating and P1 transduction showed their loci on the E. coli genetic map to be as follows: hopA in the gyrB-tnaA region, hopB in the bglB-oriC region, hopD between 8 and 15 min, and hopE in the argA-thyA region. Kinetics of stability of the sop+ and delta sop mini-F plasmids in these hop mutants suggest that the hopA mutants are defective in partitioning of mini-F rather than in plasmid replication. The hopB, hopC, and hopD mutants were partially defective in replication of mini-F. The physical structure of the plasmid DNA was normal in hopA, B, C, and D mutants. Large amounts of linear multimers of plasmid DNA accumulated in mutants of the fifth linkage group (hopE). None of the hop mutations in any linkage group affected the normal growth of cells. Images PMID:3053654

  11. Adsorption of plasmid DNA to mineral surfaces and protection against DNase I

    International Nuclear Information System (INIS)

    The adsorption of [3H]thymidine-labeled plasmid DNA (pHC314; 2.4 kb) of different conformations to chemically pure sand was studied in a flowthrough microenvironment. The extent of adsorption was affected by the concentration and valency of cations, indicating a charge-dependent process. Bivalent cations (Mg2+, Ca2+) were 100-fold more effective than monovalent cations (Na+, K+, NH4+). Quantitative adsorption of up to 1 μg of negatively supercoiled or linearized plasmid DNA to 0.7 g of sand was observed in the presence of 5 mm MgCl2 at pH 7. Under these conditions, more than 85% of DNA adsorbed within 60 s. Maximum adsorption was 4 μg of DNA to 0.7 g of sand. Supercoil molecules adsorbed slightly less than linearized or open circular plasmids. An increase of the pH from 5 to 9 decreased adsorption at 0.5 mM MgCl2 about eightfold. It is concluded that adsorption of plasmid DNA to sand depends on the neutralization of negative charges on the DNA molecules and the mineral surfaces by cations. The results are discussed on the grounds of the polyelectrolyte adsorption model. Sand-adsorbed DNA was 100 times more resistant against DNase I than was DNA free in solution. The data support the idea that plasmid DNA can enter the extracellular bacterial gene pool which is located at mineral surfaces in natural bacterial habitats

  12. Simple method for identification of plasmid-coded proteins

    International Nuclear Information System (INIS)

    Proteins encoded by plasmid DNA are specifically labeled in uv-irradiated cells of Escherichia coli carrying recA and uvrA mutations because extensive degradation of the chromosome DNA occurs concurrently with amplification of plasmid DNA

  13. Lipid hydrolysis products affect the composition of infant gut microbial communities in vitro

    DEFF Research Database (Denmark)

    Bennike, Rikke Mette Guldhammer; Bahl, Martin Iain; Vigsnæs, Louise Kristine;

    2015-01-01

    14 : 0 and MAG 12 : 0) or long-chained NEFA (LC-NEFA; 16 : 0 to 18 : 1 and MAG 16 : 0) with and without sphingosine, representing lipid hydrolysis products characteristic for intestinal hydrolysis of breast milk lipids. Ion Torrent sequencing of the bacterial 16S ribosomal RNA gene revealed that the...

  14. Colostrum and milk production of sows is affected by dietary conjugated linoleic acid

    DEFF Research Database (Denmark)

    Krogh, Uffe; Flummer, Christine; Jensen, Søren Krogh;

    2012-01-01

    The present experiment was conducted to investigate dietary effects of conjugated linoleic acid (CLA) on sow traits related to piglet survival and growth performance. A total of 23 gestating sows were fed either a standard lactation diet (control diet [CON]) or the CON supplemented with 1.3% CLA...... productivity may be improved by using different fatty acids for transition and lactating sows....

  15. Pseudomonas aeruginosa PAO1 Pyocin Production Affects Population Dynamics within Mixed-Culture Biofilms▿ †

    OpenAIRE

    Waite, Richard D.; Curtis, Michael A.

    2008-01-01

    Transcriptomic and phenotypic studies showed that pyocins are produced in Pseudomonas aeruginosa PAO1 aerobic and anaerobic biofilms. Pyocin activity was found to be high in slow-growing anaerobic biofilms but transient in aerobic biofilms. Biofilm coculture of strain PAO1 and a pyocin-sensitive isolate showed that pyocin production had a significant impact on bacterial population dynamics, particularly under anaerobic conditions.

  16. Intestinal microbial affects of yeast products on weaned and transport stressed pigs

    Science.gov (United States)

    Study objectives were to determine effects of a commercially available yeast product (XPC, Diamond-V Mills) and stress of transportation on total Enterobacteriaceae, Escherichia coli, coliforms, and Lactobacilli populations in the intestine of weaning pigs. In a RCB design with a 2 x 2 factorial ar...

  17. Pig slurry characteristics, nutrient balance and biogas production as affected by separation and acidification

    DEFF Research Database (Denmark)

    Sommer, S. G.; Hjorth, M.; Leahy, J. J.;

    2015-01-01

    Animal slurry is separated in order to avoid excessive nitrogen, phosphorus and potassium (NPK) fertilization of crops in the field. To enhance fertilizer efficiency further, slurry and its separation products may be acidified, for instance in animal houses. The current study quantified the effec...

  18. Do new cellulolytic enzyme preparations affect the industrial strategies for high solids lignocellulosic ethanol production?

    DEFF Research Database (Denmark)

    Cannella, David; Jørgensen, Henning

    2014-01-01

    Production of ethanol from lignocellulosic materials has a promising market potential, but the process is still only at pilot/demonstration scale due to the technical and economical difficulties of the process. Operating the process at very high solids concentrations (above 20% dry matter—DM) has...

  19. Statistical analysis of factors affecting crop production in Navrongo, Tono irrigation dam a case study

    Directory of Open Access Journals (Sweden)

    D. JAKPERIK

    2013-02-01

    Full Text Available This study identified the essential factors of production in the Tono irrigation dam of the Upper East Region. The accessibility and patronage of these factors by farmers in this area was studied and how they influence crop production in the Region. A total of two hundred questionnaires designed by the Ministry of Food and Agriculture for farmers in Navrongo were administered. A snowball sampling design was employed to identify farmers on these facilities in the study area. Pearson correlation coefficient, principal component analysis, and subset regression analysis were used to unveil the relevant information in the study. The results revealed a high correlation between the factors of production being studied with each pair having a probability level less than 0.0001. The full general linear model was highly significant (F=662.50, psmaller tahn 0.0001 with only two factors (Farm size and Fertilizer accounting for 98.86% of the total variation in yield. This is a clear indication of multicollinearity and a subset regression analysis was used to identify the best subset that improves yield in the irrigation dam. The best subset comprised of Age, Farm size, seed, and Fertilizer accounting for 97.75% of the total variation in crop production in Navrongo. To enhance yield in Navrongo therefore, high yielding seeds, timely granting of fertilizer credit to farmers who mature enough and responsible with reasonable farm sizes should be encouraged.

  20. Milk production traits of beef cows as affected by horn fly numbers and breed type

    Science.gov (United States)

    Pesticide resistance in horn flies indicates the need for more sustainable production systems. Cows sired by Bonsmara (BONS;n=7), Brangus (BRAN;n=13), Charolais (CHAR;n=8), Gelbvieh (GELV;n=5), Hereford (HERF;n=12), and Romosinuano (ROMO;n=8) from Brangus dams were used to determine breed difference...

  1. Phosphoribosyl pyrophosphate synthetase activity affects growth and riboflavin production in Ashbya gossypii

    Directory of Open Access Journals (Sweden)

    Revuelta José L

    2008-09-01

    Full Text Available Abstract Background Phosphoribosyl pyrophosphate (PRPP is a central compound for cellular metabolism and may be considered as a link between carbon and nitrogen metabolism. PRPP is directly involved in the de novo and salvage biosynthesis of GTP, which is the immediate precursor of riboflavin. The industrial production of this vitamin using the fungus Ashbya gossypii is an important biotechnological process that is strongly influenced by substrate availability. Results Here we describe the characterization and manipulation of two genes of A. gossypii encoding PRPP synthetase (AGR371C and AGL080C. We show that the AGR371C and AGL080C gene products participate in PRPP synthesis and exhibit inhibition by ADP. We also observed a major contribution of AGL080C to total PRPP synthetase activity, which was confirmed by an evident growth defect of the Δagl080c strain. Moreover, we report the overexpression of wild-type and mutant deregulated isoforms of Agr371cp and Agl080cp that significantly enhanced the production of riboflavin in the engineered A. gossypii strains. Conclusion It is shown that alterations in PRPP synthetase activity have pleiotropic effects on the fungal growth pattern and that an increase in PRPP synthetase enzymatic activity can be used to enhance riboflavin production in A. gossypii.

  2. Milk production traits of beef cows as affected by horn fly count and sire breed type

    Science.gov (United States)

    Horn fly infestations on beef cattle results in decreased productivity and challenges enterprise sustainability. Objective of this experiment was to determine the relationships among, cattle breed, heat shock protein 70 (Hsp70) genotype, and horn fly density. Angus (n = 20), Brahman (n = 17), and ...

  3. DISTRIBUTION OF PLASMIDS IN GROUNDWATER BACTERIA

    Science.gov (United States)

    Bacteria isolated from groundwater aquifer core materials of pristine aquifers at Lula and Pickett, Oklahoma, and from a site with a history of aromatic hydrocarbon contamination and natural renovation located at Conroe, Texas, were screened for the presence of plasmid Deoxyribon...

  4. Plasmid mediated quinolone resistance in Enterobacteriaceae

    NARCIS (Netherlands)

    Veldman, K.T.

    2014-01-01

    This thesis describes the occurrence of Plasmid Mediated Quinolone Resistance (PMQR) in Salmonella and E. coli from The Netherlands and other European countries. Furthermore, the genetic background of these genes was characterized. Fluoroquinolones are widely used antibiotics in both human and veter

  5. The influence of biofilms in the biology of plasmids

    OpenAIRE

    Cook, Laura C.C.; Dunny, Gary M.

    2014-01-01

    The field of plasmid biology has historically focused on bacteria growing in liquid culture. Surface attached communities of bacterial biofilms have recently been understood to be the normal environment of bacteria in the natural world. Thus, studies examining plasmid replication, maintenance, and transfer in biofilms are essential for a true understanding of bacterial plasmid biology. This chapter reviews the current knowledge of the interplay between bacterial biofilms and plasmids, focusin...

  6. Linear and Circular Plasmid Content in Borrelia burgdorferi Clinical Isolates

    OpenAIRE

    Iyer, Radha; Kalu, Ogori; Purser, Joye; Norris, Steven; Stevenson, Brian; Schwartz, Ira

    2003-01-01

    The genome of Borrelia burgdorferi, the etiologic agent of Lyme disease, is composed of a linear chromosome and more than 20 linear and circular plasmids. Typically, plasmid content analysis has been carried out by pulsed-field gel electrophoresis and confirmed by Southern hybridization. However, multiple plasmids of virtually identical sizes (e.g., lp28 and cp32) complicate the interpretation of such data. The present study was undertaken to investigate the complete plasmid complements of B....

  7. Plasmid DNA entry into postmitotic nuclei of primary rat myotubes.

    OpenAIRE

    Dowty, M E; Williams, P; Zhang, G.; Hagstrom, J E; Wolff, J A

    1995-01-01

    These studies were initiated to elucidate the mechanism of DNA nuclear transport in mammalian cells. Biotin- or gold-labeled plasmid and plasmid DNA expression vectors for Escherichia coli beta-galactosidase or firefly luciferase were microinjected into the cytoplasm of primary rat myotubes in culture. Plasmid DNA was expressed in up to 70% of the injected myotubes, which indicates that it entered intact, postmitotic nuclei. The nuclear transport of plasmid DNA occurred through the nuclear po...

  8. Chemical composition of tomato seeds affected by conventional and organic production systems

    International Nuclear Information System (INIS)

    Tomato is amongst the most consumed vegetables in the world, not only for its culinary versatility but also for its high nutritional value. In the last years, consumers have shown an increased concern regarding food origin and safety. The organic tomato production has been a promising alternative for the consumer offering a safer food in relation to environmental, social and nutritional aspects. This study assessed the chemical composition of tomato seeds produced in both conventional and organic systems by INAA. The results showed significant differences (p≤0.05) in the mass fractions of Br, Cs, Eu, Fe, K, Mo, Na, Rb and Sm between both systems, indicating influence of the crop management adopted in the different tomato production systems. (author)

  9. Analysis of the Factors Affecting Consumer’s Some Traditional Food Products Preferences by Multidimensional Scaling Method

    Directory of Open Access Journals (Sweden)

    Y. Oraman G. Unakıtan E. Yılmaz B. Başaran

    2011-01-01

    Full Text Available The aim of this study is to evaluate consumer behaviour towards factors affecting purchase decision of some traditional food products and grouping those consumer attitudes. The original data was obtained from results of a survey conducted in 14 different districts in Tekirdag. The survey consisted of face-to-face interviews conducted within a total sample of 166 households randomly. In the study, multidimensional scaling analysis is used for evaluating the effective factors of consumer preferences for traditional products and grouping their preferences. It is found that taste, food safety and freshness have similar effects on consumer preferences for yogurt, molasses and noodles. Price has an important and positive loaded effect on other variables for the three products.

  10. Factors affecting process temperature and biogas production in small-scale rural biogas digesters in winter in northern Vietnam

    DEFF Research Database (Denmark)

    Cuong, Pham Hung; Vu, C.C.; Sommer, Sven G.;

    2014-01-01

    and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily...... and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the...... season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry...

  11. Milk production of rabbit doe and kit mortality as affected by dietary katuk leaf meal (Sauropus androgynus L. Merr

    Directory of Open Access Journals (Sweden)

    Mubarak Akbar

    2013-12-01

    Full Text Available This study was aimed as to determining the effect of katuk (Sauropus androgynus L. Merr leaf on influence rabbit doe milk production and kits mortality during 3 weeks weeks of age. Twenty four does aged 6-12 months, divided into three blocks, of four treatment diets, were used in our replicity. The diet treatments used katuk leaf meal: 0% (P0, 1% (P1, 2% (P2, and 3% (P3. The parameters observed were: doe’s milk production, kits mortality, kit as level: body weight gain, and immune response. The results showed that supplementation of katuk leaf meal increased (P < 0,05 doe milk production and body weight gain of kits during 3 weeks experiment, whereas mortality and immune responses were not affected by katuk leaf meal supplementation.

  12. Microorganisms and dietary factors affecting biohydrogenation and conjugated linoleic acid production in the rumen ecosystem

    OpenAIRE

    Maia, Margarida Rosa Garcez

    2010-01-01

    Tese de Doutoramento em Ciências Veterinárias, especialidade de Produção Animal Consumption of animal fat has been associated with an increased incidence of chronic diseases, as cardiovascular disease, obesity and diabetes. Ruminant products, milk and meat, have high saturated fatty acids (FA) content as a result of biohydrogenation by microbial metabolic activity in the rumen. Biohydrogenation also originates FA with health promoting or disease preventing properties, including...

  13. Descriptive study of production factors affecting performance traits in growing-finishing pigs in Spain

    Directory of Open Access Journals (Sweden)

    P. S. Agostini

    2013-04-01

    Full Text Available The objective of this study was to build up a data set including productive performance and production factors data of growing-finishing (GF pigs in Spain in order to perform a representative and reliable description of the traits of Spanish growing-finishing pig industry. Data from 764 batches from 452 farms belonging to nine companies (1,157,212 pigs were collected between 2008 and 2010 through a survey including five parts: general, facilities, feeding, health status and performance. Most studied farms had only GF pigs on their facilities (94.7%, produced ‘industrial’ pigs (86.7%, had entire male and female (59.5% and Pietrain-sired pigs (70.0%, housed between 13-20 pigs per pen (87.2%, had  50% of slatted floor (70%, single-space dry feeder (54.0%, nipple drinker (88.7% and automatic ventilation systems (71.2%. A 75.0% of the farms used three feeding phases using mainly pelleted diets (91.0%, 61.3% performed three or more antibiotic treatments and 36.5% obtained water from the public supply. Continuous variables studied had the following average values: number of pigs placed per batch, 1,515 pigs; initial and final body weight, 19.0 and 108 kg; length of GF period, 136 days; culling rate, 1.4%; barn occupation, 99.7%; feed intake per pig and fattening cycle, 244 kg; daily gain, 0.657 kg; feed conversion ratio, 2.77 kg kg-1 and mortality rate, 4.3%. Data reflecting the practical situation of the Spanish growing and finishing pig production and it may contribute to develop new strategies in order to improve the productive and economic efficiency of GF pig units.

  14. Phenolic compounds affect production of pyocyanin, swarming motility and biofilm formation of Pseudomonas aeruginosa

    OpenAIRE

    Aylin Ugurlu; Aysegul Karahasan Yagci; Seyhan Ulusoy; Burak Aksu; Gulgun Bosgelmez-Tinaz

    2016-01-01

    Objective: To investigate the effects of plant-derived phenolic compounds (i.e. caffeic acid, cinnamic acid, ferulic acid and vanillic acid) on the production of quorum sensing regulated virulence factors such as pyocyanin, biofilm formation and swarming motility of Pseudomonas aeruginosa (P. aeruginosa) isolates. Methods: Fourteen clinical P. aeruginosa isolates obtained from urine samples and P. aeruginosa PA01 strain were included in the study. The antibacterial effects of phenolic comp...

  15. PRODUCTION ECONOMICS OF EGYPTIAN COTTON IN THE SALT-AFFECTED LAND

    OpenAIRE

    El-Shahat, Ali Ahmed Ibrahim Ali

    2015-01-01

    Water is the natural resource that exerts the greatest constraint on Egypt's agricultural production system. Most of Egypt's cultivated lands depend on irrigation from Nile. However, Egypt’s agriculture is under pressure to justify its use of water resource, which is scarce due to increased competition for water resources. The water management problem is currently increasing in the context of the ongoing national transition from a government-controlled market with government intervention i...

  16. Phosphoribosyl pyrophosphate synthetase activity affects growth and riboflavin production in Ashbya gossypii

    OpenAIRE

    Revuelta José L; Santos María A; Jiménez Alberto

    2008-01-01

    Abstract Background Phosphoribosyl pyrophosphate (PRPP) is a central compound for cellular metabolism and may be considered as a link between carbon and nitrogen metabolism. PRPP is directly involved in the de novo and salvage biosynthesis of GTP, which is the immediate precursor of riboflavin. The industrial production of this vitamin using the fungus Ashbya gossypii is an important biotechnological process that is strongly influenced by substrate availability. Results Here we describe the c...

  17. Genetic diversity affects productivity in early but not late stages of stand development

    Czech Academy of Sciences Publication Activity Database

    Münzbergová, Zuzana; Skálová, Hana; Hadincová, Věroslava

    2009-01-01

    Roč. 10, č. 5 (2009), s. 411-419. ISSN 1439-1791 R&D Projects: GA AV ČR IAA600050820; GA AV ČR(CZ) IAA600050623; GA ČR GA206/06/0098 Institutional research plan: CEZ:AV0Z60050516 Keywords : clonal grass * complementarity * diversity-productivity relationships Subject RIV: EF - Botanics Impact factor: 2.422, year: 2009

  18. Postsegregational killing does not increase plasmid stability but acts to mediate the exclusion of competing plasmids

    OpenAIRE

    Cooper, Tim F; Heinemann, Jack A.

    2000-01-01

    Postsegregational killing (PSK) systems consist of a tightly linked toxin–antitoxin pair. Antitoxin must be continually produced to prevent the longer lived toxin from killing the cell. PSK systems on plasmids are widely believed to benefit the plasmid by ensuring its stable vertical inheritance. However, experimental tests of this “stability” hypothesis were not consistent with its predictions. We suggest an alternative hypothesis to explain the evolution of PSK: ...

  19. Plasmid Capture by the Bacillus thuringiensis Conjugative Plasmid pXO16▿

    OpenAIRE

    Timmery, Sophie; Modrie, Pauline; Minet, Olivier; Mahillon, Jacques

    2009-01-01

    Conjugation, mobilization, and retromobilization are three related mechanisms of horizontal gene transfer in bacteria. They have been extensively studied in gram-negative species, where retromobilization, the capture of DNA from a recipient by a donor cell, was shown to result from two successive steps: the transfer of the conjugative plasmid from the donor to the recipient followed by the retrotransfer of the mobilizable plasmid to the donor. This successive model was established for gram-ne...

  20. The interactive effects of affect and shopping goal on information search and product evaluations.

    Science.gov (United States)

    Chen, Fangyuan; Wyer, Robert S; Shen, Hao

    2015-12-01

    Although shoppers often want to evaluate products to make a purchase decision, they can also shop for enjoyment. In each case, the amount of time they spend on shopping and the number of options they consider can depend on the mood they happen to be in. We predicted that mood can signal whether the goal has been attained and when people should stop processing information. When people are primarily motivated to purchase a particular type of product, positive mood signals that they have done enough. Thus, they consider less information if they are happy than if they are unhappy. When people shop for enjoyment, however, positive mood signals that they are still having fun. Thus, they consider more information when they are happy than when they are not. Four experiments among university students (N = 827) examined these possibilities. Experiment 1 provided initial evidence for the interactive effects of mood and goals on search behavior and product evaluation. Other studies examined the implications of this conceptualization for different domains: (a) the relative impact of brand and attribute information on judgments (Experiment 2), (b) gender differences in shopping behavior (Experiment 3), and (c) the number of options that people review in an actual online shopping website (Experiment 4). PMID:26460676

  1. Methyl jasmonate and miconazole differently affect arteminisin production and gene expression in Artemisia annua suspension cultures.

    Science.gov (United States)

    Caretto, S; Quarta, A; Durante, M; Nisi, R; De Paolis, A; Blando, F; Mita, G

    2011-01-01

    Artemisia annua L. is a herb traditionally used for treatment of fevers. The glandular trichomes of this plant accumulate, although at low levels, artemisinin, which is highly effective against malaria. Due to the great importance of this compound, many efforts have been made to improve knowledge on artemisinin production both in plants and in cell cultures. In this study, A. annua suspension cultures were established in order to investigate the effects of methyl jasmonate (MeJA) and miconazole on artemisinin biosynthesis. Twenty-two micro molar MeJA induced a three-fold increase of artemisinin production in around 30 min; while 200 μm miconazole induced a 2.5-fold increase of artemisinin production after 24 h, but had severe effects on cell viability. The influence of these treatments on expression of biosynthetic genes was also investigated. MeJA induced up-regulation of CYP71AV1, while miconazole induced up-regulation of CPR and DBR2. PMID:21143725

  2. Conjugative plasmids: Vessels of the communal gene pool

    DEFF Research Database (Denmark)

    Norman, Anders; Hansen, Lars H.; Sørensen, Søren Johannes

    2009-01-01

    over large taxonomic distances. These plasmids are collections of discrete regions of genes that function as ‘backbone modules' to undertake different aspects of overall plasmid maintenance and propagation. Conjugative plasmids often carry suites of ‘accessory elements' that contribute adaptive traits...

  3. Compositional discordance between prokaryotic plasmids and host chromosomes

    Directory of Open Access Journals (Sweden)

    van Kampen Antoine HC

    2006-02-01

    Full Text Available Abstract Background Most plasmids depend on the host replication machinery and possess partitioning genes. These properties confine plasmids to a limited range of hosts, yielding a close and presumably stable relationship between plasmid and host. Hence, it is anticipated that due to amelioration the dinucleotide composition of plasmids is similar to that of the genome of their hosts. However, plasmids are also thought to play a major role in horizontal gene transfer and thus are frequently exchanged between hosts, suggesting dinucleotide composition dissimilarity between plasmid and host genome. We compared the dinucleotide composition of a large collection of plasmids with that of their host genomes to shed more light on this enigma. Results The dinucleotide frequency, coined the genome signature, facilitates the identification of putative horizontally transferred DNA in complete genome sequences, since it was found to be typical for a certain genome, and similar between related species. By comparison of the genome signature of 230 plasmid sequences with that of the genome of each respective host, we found that in general the genome signature of plasmids is dissimilar from that of their host genome. Conclusion Our results show that the genome signature of plasmids does not resemble that of their host genome. This indicates either absence of amelioration or a less stable relationship between plasmids and their host. We propose an indiscriminate lifestyle for plasmids preserving the genome signature discordance between these episomes and host chromosomes.

  4. Identification of significant medium components that affect docosahexaenoic acid production by Schizochytrium sp. SW1

    Science.gov (United States)

    Manikan, Vidyah; Hamid, Aidil A.

    2013-11-01

    Central composite design (CCD) was employed to investigate the significance of glucose, yeast extract, MSG and sea salt in affecting the amount of docosahexaenoic acid (DHA) accumulated by a locally isolated strain of Schizochytrium. Design Expert software was used to construct a set of experiments where each medium component mentioned above was varied over three levels. Cultivation was carried out in 250mL flasks containing 50mL of medium, incubated at 30°C with 200 rpm agitation for 96 hours. ANOVA was conducted to identify the influential factors and the level of their significance where factors that scored a probability value of less than 0.05 were considered significant. The level of influence for each independent variable was also interpreted using perturbation whereas pattern of interaction between the factors were interpreted using interaction plots. This experiment revealed that yeast extract and monosodium glutamate have significant influence on DHA accumulation process by Schizochytrium sp. SW1.

  5. Social Factors Affecting Wetlands Utilization for Agriculture in Nigeria: A case study of sawah rice production

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Wetlands have immense poverty-fighting potentials and in Nigeria,more and more people are dependent on wetlands for their livelihoods.To examine the social factors affecting the current status of the wetlands utilization for agriculture in Nigeria,a simple random sampling technique was used to select 200 farmers cultivating wetlands and a structured questionnaire was applied to elicit the information on the social factors.Data collected were described using frequency and percentage and a multiple regression analysis was used to identify significant variables that are determinants of wetland utilization.The results of the analysis showed that significant variables included crop preferences,farming system,culture,taste,land tenure,knowledge of wetland cultivation,perceived suitability,farmers' tribe,location of wetland,and farmers' age.It was concluded with suggestions for the right combination of policies,public awareness,and appropriate farming methods in order to improve wetland utilization in Nigeria.

  6. Carnosine inhibits KRAS-mediated HCT116 proliferation by affecting ATP and ROS production.

    Science.gov (United States)

    Iovine, Barbara; Iannella, Maria Luigia; Nocella, Francesca; Pricolo, Maria Rosaria; Bevilacqua, Maria Assunta

    2012-02-28

    Carnosine is a natural dipeptide that has generated particular interest for its antioxidant, anti-aging and especially for its antiproliferative properties. In this study, we demonstrate that carnosine inhibits the proliferation of human HCT116 colon cancer cells. In this cell line, the activating KRAS mutation induces mitochondrial ROS, the signaling molecules for cell proliferation. We observed that 50-100 mM carnosine decreases ATP and ROS concentration and induces cell cycle arrest in G1 phase. In HCT116 cells these effects are related to decreased ERK1/2 phosphorylation and increased p21waf1 protein. Our findings support the concept that carnosine could inhibit HCT116 cell growth via its antioxidant activity and its ability to affect glycolysis. PMID:22137144

  7. Comparative genomics of multidrug resistance-encoding IncA/C plasmids from commensal and pathogenic Escherichia coli from multiple animal sources.

    Directory of Open Access Journals (Sweden)

    Claudia Fernández-Alarcón

    Full Text Available Incompatibility group A/C (IncA/C plasmids have received recent attention for their broad host range and ability to confer resistance to multiple antimicrobial agents. Due to the potential spread of multidrug resistance (MDR phenotypes from foodborne pathogens to human pathogens, the dissemination of these plasmids represents a public health risk. In this study, four animal-source IncA/C plasmids isolated from Escherichia coli were sequenced and analyzed, including isolates from commercial dairy cows, pigs and turkeys in the U.S. and Chile. These plasmids were initially selected because they either contained the floR and tetA genes encoding for florfenicol and tetracycline resistance, respectively, and/or the bla(CMY-2 gene encoding for extended spectrum β-lactamase resistance. Overall, sequence analysis revealed that each of the four plasmids retained a remarkably stable and conserved backbone sequence, with differences observed primarily within their accessory regions, which presumably have evolved via horizontal gene transfer events involving multiple modules. Comparison of these plasmids with other available IncA/C plasmid sequences further defined the core and accessory elements of these plasmids in E. coli and Salmonella. Our results suggest that the bla(CMY-2 plasmid lineage appears to have derived from an ancestral IncA/C plasmid type harboring floR-tetAR-strAB and Tn21-like accessory modules. Evidence is mounting that IncA/C plasmids are widespread among enteric bacteria of production animals and these emergent plasmids have flexibility in their acquisition of MDR-encoding modules, necessitating further study to understand the evolutionary mechanisms involved in their dissemination and stability in bacterial populations.

  8. Competition between Plasmid-Bearing and Plasmid-Free Organisms in a Chemostat with Pulsed Input and Washout

    OpenAIRE

    Sanling Yuan; Yu Zhao; Anfeng Xiao

    2009-01-01

    We consider a model of competition between plasmid-bearing and plasmid-free organisms in the chemostat with pulsed input and washout. We investigate the subsystem with nutrient and plasmid-free organism and study the stability of the boundary periodic solutions, which are the boundary periodic solutions of the system. The stability analysis of the boundary periodic solution yields the invasion threshold of the plasmid-bearing organism. By using the standard techniques of bifurcation theory, w...

  9. Co-segregation of yeast plasmid sisters under monopolin-directed mitosis suggests association of plasmid sisters with sister chromatids

    OpenAIRE

    Liu, Yen-Ting; Ma, Chien-Hui; Jayaram, Makkuni

    2013-01-01

    The 2-micron plasmid, a high copy extrachromosomal element in Saccharomyces cerevisiae, propagates itself with nearly the same stability as the chromosomes of its host. Plasmid stability is conferred by a partitioning system consisting of the plasmid-coded proteins Rep1 and Rep2 and a cis-acting locus STB. Circumstantial evidence suggests that the partitioning system couples plasmid segregation to chromosome segregation during mitosis. However, the coupling mechanism has not been elucidated. ...

  10. Transfer from long to short photoperiods affects production efficiency of day-neutral rice

    Science.gov (United States)

    Goldman, K. R.; Mitchell, C. A.

    1999-01-01

    The day-neutral, semidwarf rice (Oryza sativa L.) cultivar Ai-Nan-Tsao was grown in a greenhouse under summer conditions using high-pressure sodium lamps to extend the natural photoperiod. After allowing 2 weeks for germination, stand establishment, and thinning to a consistent planting density of 212 plants/m2, stands were maintained under continuous lighting for 35 or 49 days before shifting to 8- or 12-h photoperiods until harvest 76 days after planting. Non-shifted control treatments consisting of 8-, 12-, or 24-h photoperiods also were maintained throughout production. Tiller number increased as duration of exposure to continuous light increased before shifting to shorter photoperiods. However, shoot harvest index and yield efficiency rate were lower for all plants receiving continuous light than for those under the 8- or 12-h photoperiods. Stands receiving 12-h photoperiods throughout production had the highest grain yield per plant and equaled the 8-h-photoperiod control plants for the lowest tiller number per plant. As long as stands were exposed to continuous light, tiller formation continued. Shifting to shorter photoperiods late in the cropping cycle resulted in newly formed tillers that were either sterile or unable to mature grain before harvest. Late-forming tillers also suppressed yield of grain in early-forming tillers, presumably by competing for photosynthate or for remobilized assimilate during senescence. Stands receiving 12-h photoperiods throughout production not only produced the highest grain yield at harvest but had the highest shoot harvest index, which is important for resource-recovery strategies in advanced life-support systems proposed for space.

  11. Evaluation of Factors Affecting Polyhydroxyalkanoates Production by Comamonas sp. EB172 Using Central Composite Design

    Directory of Open Access Journals (Sweden)

    Noor Azman Mohd Johar

    2012-09-01

    Full Text Available Aims: Statistical approach, central composite design (CCD was used to investigate the complex interaction among temperature (25-37 °C, initial medium pH (5-9, inoculum size (4-10 % (v/v, concentration of (NH42SO4 (0-1 g/L and concentration of mixed organic acids (5-10 g/L in the production of polyhydroxyalkanoates by Comamonas sp. EB172.Methodology and Results: Mixed organic acids derived from anaerobically treated palm oil mill effluent (POME containing acetic:propionic:butyric (ratio of 3:1:1 were used as carbon source in the batch culture of Comamonas sp. EB172 to produce polyhydoxyalkanoates (PHAs. The analysis of variance (ANOVA showed that all five factors were significantly important in the batch fermentation by shake flask with a P value of less than 0.001. The optimal temperature, initial medium pH, inoculum size, concentration of (NH42SO4 and concentration of mixed organic acids were 30 °C, 7.04, 4.0 % (v/v, 0.01 g/L and 5.05 g/L respectively.Conclusion, significance and impact of study: Optimization of the production medium containing mixed organic acids has improved the PHA production for more than 2 folds. Under optimal condition in the shake flask fermentation, the predicted growth is 2.98 g/L of dry cell weight (DCW with 47.07 wt % of PHA content. The highest yield of PHA was 0.28 g of PHA per g mixed organic acids.

  12. Productivity of taggar goats as affected by sex of kids and litter size

    Directory of Open Access Journals (Sweden)

    Bushara I

    2013-06-01

    Full Text Available The study was conducted in Taggar goats to evaluate the effect of two different levels of protein and energy in the rations on some reproductive and productive traits. Sixty two (62 kids of Taggar goats were allocated to sex and birth type in a complete randomized design according to live body weight. The results indicated that supplemented does secured higher litter size 1.50 and 1.33 compared to control group 1.2. Kidding rate was high in supplemented groups 100% compared with control group 93.8%. Body weight was heavier at time of kidding and weaning for supplemented does compared with control does. These results indicated that supplementation reduced body weight losses throughout the lactation period. The kidding interval for the supplemented does was shorter 247.81±8.38 and 242.60±7.88 days for does in groups B and C respectively compared to does in control group, 288.94±6.84 days. Similarly, the service period had been reduced in supplemented does than those in control group. Results from milk analysis indicated that higher protein, lactose and total solid content in supplemented does whereby fat content was higher in control group. The supplementation had reduced the incidence of abortion and mortality rates compared to the un supplemented does. In conclusion the investigated environmental factors showed an impact on both reproductive and productive traits of the Taggar goats under rangeland farming system. Keywords: Taggar goats, production, reproduction, concentrate ration, dry land.

  13. Nutrient availability affects pigment production but not growth in lichens of biological soil crusts

    Science.gov (United States)

    Bowker, M.A.; Koch, G.W.; Belnap, J.; Johnson, N.C.

    2008-01-01

    Recent research suggests that micronutrients such as Mn may limit growth of slow-growing biological soil crusts (BSCs) in some of the drylands of the world. These soil surface communities contribute strongly to arid ecosystem function and are easily degraded, creating a need for new restoration tools. The possibility that Mn fertilization could be used as a restoration tool for BSCs has not been tested previously. We used microcosms in a controlled greenhouse setting to investigate the hypothesis that Mn may limit photosynthesis and consequently growth in Collema tenax, a dominant N-fixing lichen found in BSCs worldwide. We found no evidence to support our hypothesis; furthermore, addition of other nutrients (primarily P, K, and Zn) had a suppressive effect on gross photosynthesis (P = 0.05). We also monitored the growth and physiological status of our microcosms and found that other nutrients increased the production of scytonemin, an important sunscreen pigment, but only when not added with Mn (P = 0.01). A structural equation model indicated that this effect was independent of any photosynthesis-related variable. We propose two alternative hypotheses to account for this pattern: (1) Mn suppresses processes needed to produce scytonemin; and (2) Mn is required to suppress scytonemin production at low light, when it is an unnecessary photosynthate sink. Although Mn fertilization does not appear likely to increase photosynthesis or growth of Collema, it could have a role in survivorship during environmentally stressful periods due to modification of scytonemin production. Thus, Mn enrichment should be studied further for its potential to facilitate BSC rehabilitation. ?? 2008 Elsevier Ltd.

  14. Magnetic nanowires and hyperthermia: How geometry and material affect heat production efficiency

    KAUST Repository

    Contreras, M. F.

    2015-05-01

    Magnetic hyperthermia, which refers to the production of heat by magnetic nanostructures under an alternating magnetic field (AMF), has been previously investigated with superparamagnetic nanobeads as a cancer therapy method. Magnetic nanowires (NWs) used in hyperthermia can be very promising, as it has been shown that they have a larger magnetic moment per unit of volume compared to the nanobeads. Moreover, Fe NWs proved to have a higher heating efficiency compared to Fe nanobeads, when exposed to an AMF at the same concentration [1].

  15. How Does A Decrease In Oil Production Affect The World Economy?

    OpenAIRE

    Naohiko Yahaba

    2010-01-01

    The world's oil consumption has been increasing for more than a century with a few exceptions. However, there would be a possibility that the recent increase in oil consumption in developing countries such as China and India tighten the long term oil market. Since the exact amount of oil reserves is unknown, it is difficult to predict when the ultimate decrease in oil production will come. However, for the last two decades, the amount of oil consumption per year has surpassed the amount of oi...

  16. How does a decrease in oil production affect the world's economy?

    OpenAIRE

    Naohiko Yahaba

    2010-01-01

    The world's oil consumption has been increasing for more than a century with a few exceptions. However, there would be a possibility that the recent increase in oil consumption in developing countries such as China and India tighten the long term oil market. Since the exact amount of oil reserves is unknown, it is difficult to predict when the ultimate decrease in oil production will come. However, for the last two decades, the amount of oil consumption per year has surpassed the amount of oi...

  17. Market oriented new product development: How can a means-end chain approach affect the process?

    DEFF Research Database (Denmark)

    Søndergaard, Helle Alsted

    Few disagree on the advantage of market oriented product development. However, can a well-known theory on consumer behaviour be used as a catalyst for achieving it? This paper describes a case study where means-end chain (MEC) approach was introduced to a cross-functional development team at two...... different stages of the development process. Results show that MEC data is perceived as a good way of gaining knowledge about consumers; that the information serves well as the basis of discussions and for keeping project goals fixed. The results also indicate that MEC data are most valuable to the team in...... the early stages of development process....

  18. Conservation of plasmid DNA sequences in coronatine-producing pathovars of Pseudomonas syringae

    Energy Technology Data Exchange (ETDEWEB)

    Bender, C.L.; Young, S.A. (Oklahoma State Univ., Stillwater (United States)); Mitchell, R.E. (Dept. of Scientific and Industrial Research, Auckland (New Zealand))

    1991-04-01

    In Pseudomonas syringae pv. tomato PT23.2, plasmid pPT23A (101 kb) is involved in synthesis of the phytotoxin coronatine. The physical characterization of mutations that abolished coronatine production indicated that at least 30 kb of pPT23A DNA are required for toxin synthesis. In the present study, {sup 32}P-labeled DNA fragments from the 30-kb region of pPT23A hybridized to plasmid DNAs from several coronatine-producing pathovars of P. syringae under conditions of high stringency. These experiments indicated that this region of pPT23A was strongly conserved in large plasmids (90 to 105 kb) that reside in P. syringae pv. atropurpurea, glycinea, and morsprunorum. The functional significance of the observed homology was demonstrated in marker-exchange experiments in which Tn5-inactivated sequences from the 30-kb region of pPT23A were used to mutate coronatine synthesis genes in the three heterologous pathovars. Physical characterization of the Tn5 insertions generated by marker exchange indicated that genes controlling coronatine synthesis in P. syringae pv. atropurpurea 1304, glycinea 4180, and morsprunorum 567 and 3714 were located on the large indigenous plasmids where homology was originally detected. Therefore, coronatine biosynthesis genes are strongly conserved in the plasmid DNAs of four producing pathovars, despite their disparate origins (California, Japan, New Zealand, Great Britain, and Italy).

  19. Inducible expression of photoacoustic reporter gene tyrosinase in cells using a single plasmid

    Science.gov (United States)

    Paproski, Robert J.; Zemp, Roger J.

    2012-02-01

    We have previously demonstrated that tyrosinase is a reporter gene for photoacoustic imaging since tyrosinase is the rate-limiting step in the synthesis of melanin, a pigment capable of producing strong photoacoustic signals. We previously created a cell line capable of inducible tyrosinase expression (important due to toxicity of melanin) by stably transfecting tyrosinase in MCF-7 Tet-OnR cell line (Clontech) which expresses a doxycycline-controlled transactivator. Unfortunately, Clontech provides few Tet-On Advanced cell lines making it difficult to have inducible tyrosinase expression in cell lines not provided by Clontech. In order to simplify the creation of cell lines with inducible expression of tyrosinase, we created a single plasmid that encodes both the transactivator as well as tyrosinase. PCR was used to amplify both the transactivator and tyrosinase from the Tet-OnR Advanced and pTRE-Tight-TYR plasmids, respectively. Both PCR products were cloned into the pEGFP-N1 plasmid and the newly created plasmid was transfected into ZR-75-1, MCF-7, and MIA PaCa-1 cells using lipofectamine. After several days, brown melanin was only observed in cells incubated with doxycycline, suggesting that the newly created single plasmid allowed inducible tyrosinase expression in many different cells lines.

  20. Conservation of plasmid DNA sequences in coronatine-producing pathovars of Pseudomonas syringae

    International Nuclear Information System (INIS)

    In Pseudomonas syringae pv. tomato PT23.2, plasmid pPT23A (101 kb) is involved in synthesis of the phytotoxin coronatine. The physical characterization of mutations that abolished coronatine production indicated that at least 30 kb of pPT23A DNA are required for toxin synthesis. In the present study, 32P-labeled DNA fragments from the 30-kb region of pPT23A hybridized to plasmid DNAs from several coronatine-producing pathovars of P. syringae under conditions of high stringency. These experiments indicated that this region of pPT23A was strongly conserved in large plasmids (90 to 105 kb) that reside in P. syringae pv. atropurpurea, glycinea, and morsprunorum. The functional significance of the observed homology was demonstrated in marker-exchange experiments in which Tn5-inactivated sequences from the 30-kb region of pPT23A were used to mutate coronatine synthesis genes in the three heterologous pathovars. Physical characterization of the Tn5 insertions generated by marker exchange indicated that genes controlling coronatine synthesis in P. syringae pv. atropurpurea 1304, glycinea 4180, and morsprunorum 567 and 3714 were located on the large indigenous plasmids where homology was originally detected. Therefore, coronatine biosynthesis genes are strongly conserved in the plasmid DNAs of four producing pathovars, despite their disparate origins (California, Japan, New Zealand, Great Britain, and Italy)

  1. Characterization of an IncA/C Multidrug Resistance Plasmid in Vibrio alginolyticus.

    Science.gov (United States)

    Ye, Lianwei; Li, Ruichao; Lin, Dachuan; Zhou, Yuanjie; Fu, Aisi; Ding, Qiong; Chan, Edward Wai Chi; Yao, Wen; Chen, Sheng

    2016-05-01

    Cephalosporin-resistant Vibrio alginolyticus was first isolated from food products, with β-lactamases encoded by blaPER-1, blaVEB-1, and blaCMY-2 being the major mechanisms mediating their cephalosporin resistance. The complete sequence of a multidrug resistance plasmid, pVAS3-1, harboring the blaCMY-2 and qnrVC4 genes was decoded in this study. Its backbone exhibited genetic homology to known IncA/C plasmids recoverable from members of the family Enterobacteriaceae, suggesting its possible origin in Enterobacteriaceae. PMID:26976864

  2. TOL Plasmid Carriage Enhances Biofilm Formation and Increases Extracellular DNA Content in Pseudomonas Putida KT2440

    DEFF Research Database (Denmark)

    Smets, Barth F.; D'Alvise, Paul; Yankelovich, T.; Sjøholm, O.; Jin, Y.; Wuertz, S.

    Adherent growth of Pseudomonas putida KT2440 with and without the TOL plasmid (pWWO) at the solid-liquid and air-liquid interface was examined. We compared biofilm formation on glass in flow cells, and assayed pellicle (air-liquid interface biofilm) formation in stagnant liquid cultures by confocal...... laser scanning microscopy. The TOL-carrying strains formed pellicles and thick biofilms, whereas the same strains without the plasmid displayed little adherent growth. Microscopy using fluorescent nucleic acid- specific stains (cytox orange, propidium iodide) revealed differences in production of...

  3. Bioaugmentation of Hydrogenispora ethanolica LX-B affects hydrogen production through altering indigenous bacterial community structure.

    Science.gov (United States)

    Yang, Zhiman; Guo, Rongbo; Shi, Xiaoshuang; He, Shuai; Wang, Lin; Dai, Meng; Qiu, Yanling; Dang, Xiaoxiao

    2016-07-01

    Bioaugmentation can facilitate hydrogen production from complex organic substrates, but it still is unknown how indigenous microbial communities respond to the added bacteria. Here, using a Hydrogenispora ethanolica LX-B (named as LX-B) bioaugmentation experiments, the distribution of metabolites and the responses of indigenous bacterial communities were investigated via batch cultivation (BC) and repeated batch cultivation (RBC). In BC the LX-B/sludge ratio of 0.12 achieved substantial high hydrogen yield, which was over twice that of control. In RBC one-time bioaugmentation and repeated batch bioaugmentation of LX-B resulted in the hydrogen yield that was average 1.2-fold and 0.8-fold higher than that in control, respectively. This improved hydrogen production performance mainly benefited from a shift in composition of the indigenous bacterial community caused by LX-B bioaugmentation. The findings represented an important step in understanding the relationship between bioaugmentation, a shift in bacterial communities, and altered bioreactor performance. PMID:27023388

  4. Egg-laying "intermorphs" in the ant Crematogaster smithi neither affect sexual production nor male parentage.

    Science.gov (United States)

    Oettler, Jan; Dijkstra, Michiel B; Heinze, Jürgen

    2013-01-01

    We study male parentage and between-colony variation in sex allocation and sexual production in the desert ant Crematogaster smithi, which usually has only one singly-mated queen per nest. Colonies of this species are known to temporarily store nutrients in the large fat body of intermorphs, a specialized female caste intermediate in morphology between queens and workers. Intermorphs repackage at least part of this fat into consumable but viable male-destined eggs. If these eggs sometimes develop instead of being eaten, intermorphs will be reproductive competitors of the queen but--due to relatedness asymmetries--allies of their sister worker. Using genetic markers we found a considerable proportion of non-queen sons in some, but not all, colonies. Even though intermorphs produce ∼1.7× more eggs than workers, their share in the parentage of adult males is estimated to be negligible due to their small number compared to workers. Furthermore, neither colony-level sex allocation nor overall sexual production was correlated with intermorph occurrence or number. We conclude that intermorph-laid eggs typically do not survive and that the storage of nutrients and their redistribution as eggs by intermorphs is effectively altruistic. PMID:24130699

  5. Do interactions of land use and climate affect productivity of waterbirds and prairie-pothole wetlands?

    Science.gov (United States)

    Anteau, Michael J.

    2012-01-01

    Availability of aquatic invertebrates on migration and breeding areas influences recruitment of ducks and shorebirds. In wetlands of Prairie Pothole Region (PPR), aquatic invertebrate production primarily is driven by interannual fluctuations of water levels in response to wet-dry cycles in climate. However, this understanding comes from studying basins that are minimally impacted by agricultural landscape modifications. In the past 100–150 years, a large proportion of wetlands within the PPR have been altered; often water was drained from smaller to larger wetlands at lower elevations creating consolidated, interconnected basins. Here I present a case study and I hypothesize that large basins receiving inflow from consolidation drainage have reduced water-level fluctuations in response to climate cycles than those in undrained landscapes, resulting in relatively stable wetlands that have lower densities of invertebrate forage for ducks and shorebirds and also less foraging habitat, especially for shorebirds. Furthermore, stable water-levels and interconnected basins may favor introduced or invasive species (e.g., cattail [Typha spp.] or fish) because native communities "evolved" in a dynamic and isolated system. Accordingly, understanding interactions between water-level fluctuations and landscape modifications is a prerequisite step to modeling effects of climate change on wetland hydrology and productivity and concomitant recruitment of waterbirds.

  6. THE INTEGRATED STATE OF THE ROLLING-CIRCLE PLASMID PTB913 IN THE COMPOSITE BACILLUS PLASMID PTB19

    NARCIS (Netherlands)

    OSKAM, L; HILLENGA, DJ; VENEMA, G; BRON, S

    1992-01-01

    pTB19, a 27 kb plasmid originating from a thermophilic Bacillus species, contains integrated copies of two rolling-circle type plasmids on a 10.6 kb DNA fragment. In the present study we analysed the part of pTB19 that contains the rolling-circle plasmid pTB913 and the region in between the two roll

  7. Diversity and epidemiology of plasmids from Enterobacteriaceae from human and non-human reservoirs

    DEFF Research Database (Denmark)

    Bielak, Eliza Maria

    The family of Enterobacteriaceae is comprised of Gram negative bacteria found in a variety of natural environments as well as in the gastrointestinal (GI) tracts of humans and many animals including diverse mammals, birds and reptiles. Three species of the enteric bacteria are largely responsible...... also Gram positive bacteria. In particular, aminopenicillins, cephalosporins and carbapenems found broad application in treatment of infections caused by the aforementioned enteric species. Recently however, increasing levels of resistance to ß-lactams is observed in these key infectious agents as well...... plasmids can circulate between enteric bacteria from humans and food production animals; and if so, then which of these plasmid species are specifically associated with the epidemic types of blaTEM genes in Enterobacteriaceae. Furthermore, the association of the plasmid encoded blaTEM genes with...

  8. Breaks in plasmid DNA strand induced by laser radiation at a wavelength of 193 nm

    International Nuclear Information System (INIS)

    DNA of plasmid pB322 irradiated with laser at a wavelength of 193 nm was treated with an extract containing proteins from E.coli K12 AB1157 (wild-type). The enzymes were found to produce single- and double-strand DNA breaks, which was interpreted as a transformation of a portion of cyclobutane pyrimidine dimers and (6-4) photoproducts into nonrepairable single-strand DNA breaks. The products resulted from ionization of DNA, in particular, single-strand breaks, transform to double-strand breaks. A comparison of these data with the data on survival of plasmid upon transformation of E.coli K12 AB1157 enables one to assess the biological significance of single- and double-strand breaks. The inactivation of the plasmid is mainly determined by the number of directly formed laser-induced single-strand breaks. 26 refs.; 2 figs

  9. Potato Production as Affected by Crop Parameters and Meteoro Logical Elements

    Science.gov (United States)

    Pereira, André B.; Villa Nova, Nilson A.; Pereira, Antonio R.

    Meteorological elements directly influence crop potential productivity, regulating its transpiration, photosynthesis, and respiration processes in such a way as to control the growth and development of the plants throughout their physiological mechanisms at a given site. The interaction of the meteorological factors with crop responses is complex and has been the target of attention of many researchers from all over the world. There is currently a great deal of interest in estimating crop productivity as a function of climate by means of different crop weather models in order to help growers choose planting locations and timing to produce high yields with good tuber quality under site-specific atmospheric conditions. In this manuscript an agrometeorological model based on maximum carbon dioxide assimilation rates for C3 plants, fraction of photosynthetically active radiation, air temperature, photoperiod duration, and crop parameters is assessed as to its performance under tropical conditions. Crop parameters include leaf areaand harvest indexes, dry matter content of potato tubers, and crop cycles to estimate potato potential yields. Productivity obtained with the cultivar Itararé, grown with adequate soil water supply conditions at four different sites in the State of São Paulo (Itararé, Piracicaba, TatuÍ, and São Manuel), Brazil, were used to test the model. The results showed thatthe agrometeorological model tested under the climatic conditions of the State of São Paulo in general underestimated irrigated potato yield by less than 10%.This justifies the recommendation to test the performance of the model in study in other climaticregions for different crops and genotypes under optimal irrigationconditions in further scientific investigations. We reached the conclusion that the agrometeorological model taking into account information on leaf area index, photoperiod duration, photosynthetically active radiation and air temperature is feasible to estimate

  10. Interval between first dose and booster affected antibody production in cattle vaccinated against rabies

    Directory of Open Access Journals (Sweden)

    A. Albas

    2006-01-01

    Full Text Available In this study, we compared the levels of neutralizing antibodies induced by inactivated rabies vaccine in cattle by using three alternative immunization procedures. Forty-five bovines (breed nelore were then organized in three groups (A, B and C, with 15 animals/group. Group A received only one vaccine dose at day zero and Group B received the first dose at day zero and then another dose at day 30 (early booster. Group C was also immunized with two doses; however, the booster was postponed until day 180 after the first dose (delayed booster. Blood samples were withdrawn at days zero (before the first dose and 30, 210, 390, and 540 after the beginning of immunization and the antibody titers were evaluated by mouse neutralization test. The protocol used to immunize Group C (booster at day 180 was clearly more efficient. In this group, antibody levels were higher and also remained higher for longer periods in comparison with the other two groups. These results show that booster timing significantly affected antibody levels. Therefore, programs addressed to control this disease in cattle should consider not only the use of a booster but also its administration time.

  11. Alginate production affects Pseudomonas aeruginosa biofilm development and architecture, but is not essential for biofilm formation

    DEFF Research Database (Denmark)

    Stapper, A.P.; Narasimhan, G.; Oman, D.E.;

    2004-01-01

    Extracellular polymers can facilitate the non-specific attachment of bacteria to surfaces and hold together developing biofilms. This study was undertaken to qualitatively and quantitatively compare the architecture of biofilms produced by Pseudomonas aeruginosa strain PAO1 and its alginate...... biofilm formation using confocal laser scanning microscopy. Biofilm Image Processing (BIP) and Community Statistics (COMSTAT) software programs were used to provide quantitative measurements of the two-dimensional biofilm images. All three strains formed distinguishable biofilm architectures, indicating...... that the production of alginate is not critical for biofilm formation. Observation over a period of 5 days indicated a three-stage development pattern consisting of initiation, establishment and maturation. Furthermore, this study showed that phenotypically distinguishable biofilms can be...

  12. How forest management affects ecosystem services, including timber production and economic return

    DEFF Research Database (Denmark)

    Duncker, Philipp S.; Raulund-Rasmussen, Karsten; Gundersen, Per;

    2012-01-01

    processes. However, forests provide further services, including carbon sequestration, water quantity and quality, and preservation of biodiversity. In order to develop and implement strategies for sustainable forest management, it is important to anticipate the long-term effects of different forest......Forest ecosystems deliver multiple goods and services and, traditionally, forest owners tend to have a high interest in goods in the form of merchantable wood. As a consequence, forest management often aims to increase timber production and economic returns through intervention into natural...... management alternatives on the ability of the forest to provide ecosystem goods and services. Management objectives might emphasize economic interests at the expense of other services. Very few attempts have been made to illustrate and evaluate quantitatively the relationship between forest goods and...

  13. Using Saline Water in Salt Affected Soils to Enhance Food Productivity and Farmer Incomes in Bangladesh

    International Nuclear Information System (INIS)

    Bangladesh is a deltaic country with a total area of 147,570 km2, agriculture accounting for a major sector of the national economy. The coastal regions that occupy about 20% of the country's land area are very fertile and are used primarily to grow rice. During the rice season from April to the harvest in August river water as well as monsoon rainwater, harvested in large ponds and natural depressions, is used to flood the rice. During the subsequent months of dry season the intrusion of tidal water from the coast causes the soil and water salinity to increase from around 1 ppt (parts of salt per thousand grams of soil or water) in August to 8 ppt or more in April. This natural salinization is a major threat to crop production, so that about 90% of these potentially arable lands remain unused during the dry season. Key challenges to increasing the cropping intensity of these fertile lands are to use the collected pond water, consisting during the dry season of a mixture of rainwater and saline ground- and tidal waters, for crop irrigation without aggravating the natural soil and groundwater salinity, and to identify crops that will thrive in these saline conditions. In order to meet these challenges, irrigation must be applied at the right time and in the optimal amount for each type of crop so as to minimise the use of groundwater that would otherwise cause a further ingress of saline seawater and a resultant increase in soil salinity. Through an IAEA technical cooperation project, the Bangladesh Institute of Nuclear Agriculture identified and assessed crop varieties for their tolerance to salinity and evaluated the use of water from ponds and natural depressions for drip irrigation during the fallow period from August to April at pilot sites in the Noakhali and Satkhira coastal regions. Saline-tolerant varieties of wheat, mung bean, mustard, sesame, chickpea, tomato and groundnuts were identified using the carbon isotope discrimination methodology and made

  14. Seedling quality of common sage (Salvia officinalis L. as affected by seedling production methods

    Directory of Open Access Journals (Sweden)

    Ömer Çalişkan

    2006-09-01

    Full Text Available The study was conducted to determine the effects of four different seedling production methods (i.e., open seedbed, greenhouse seedbed, float system and modified float system on the seedling growth and quality of common sage. Sowing rates were 1 g per m2 in an open seedbed and a greenhouse seedbed system, whereas the sowing rate was one seed per cell in the float and modified float systems. Emergence period, seedling growth period, the fresh and dry weights of aerial parts of seedlings, the fresh and dry weights of roots, seedling height, root height and stem diameter were determined as agronomical observations and measurements. The greenhouse seedling method was found to be superior over the other methods

  15. Ownership options, financing structures, and regulatory considerations affecting independent power production projects

    International Nuclear Information System (INIS)

    In this paper is a framework for analysis of the legal, financing, and policy differences between independent power production projects (IPPs) and projects with qualifying facility status (QFs) under the Public Utility Regulatory Policies Act (PURPA). At a basic level, there is no fundamental difference in types of ownership and financing structures available to IPPs and QFS. The key consideration, though, is the regulatory and legal implications to project participants. Significant issues arise for equity participants, lenders, developers, and project operators that are considering IPP projects. Of course, many of these same issues apply to certain types of QF projects that are not fully exempt from the Public Utility Holding Company Act (PUHCA) and the Federal Power Act (FPA)

  16. Microvesicle formulations used in topical drugs and cosmetics affect product efficiency, performance and allergenicity

    DEFF Research Database (Denmark)

    Madsen, Jakob Torp; Ejner Andersen, Klaus

    2010-01-01

    Attempts to improve the formulations of topical products are continuing processes (ie, to increase cosmetic performance, enhance effects, and protect ingredients from degradation). The development of micro- and nanovesicular systems has led to the marketing of topical drugs and cosmetics that use...... these technologies. Several articles have reported improved clinical efficacy by the encapsulation of pharmaceuticals in vesicular systems, and the numbers of publications and patents are rising. Some vesicular systems may deliver the drug deeper in the skin as compared to conventional vehicles, or even make...... transdermal delivery more efficient for a number of drugs. Vesicular systems may also allow a more precise drug delivery to the site of action (ie, the hair follicles) and thereby minimize the applied drug concentration, reducing potential side effects. On the other hand, this may increase the risk of other...

  17. The factors affecting the green brand equity of electronic products: Green marketing

    Directory of Open Access Journals (Sweden)

    Narges Delafrooz

    2015-12-01

    Full Text Available This study is intentionally functional, and, from the data collection aspect, is a descriptive survey. The statistical data for the present study includes low-power electronic and electric products in Guilan Province. A total of 384 consumers were chosen using the random cluster sampling method. We have used confirmatory factor analysis and structural equation modeling to analyze the given data. The findings show that there is a significant relationship among brand-perceived quality, green brand image, (GBI and brand value, but not with the green brand-perceived value (GBPV. In addition, the results of the study show that brand credibility has a significant relationship with the GBPV and GBI, but not with the GBPV and GBI, each of which are associated with the green brand in a different way. At the end of this survey, you will read about the intermediate variables, all of which are acceptable, except the intermediate variables of brand credibility and GBI.

  18. How wing kinematics affect power requirements and aerodynamic force production in a robotic bat wing

    International Nuclear Information System (INIS)

    Bats display a wide variety of behaviors that require different amounts of aerodynamic force. To control and modulate aerodynamic force, bats change wing kinematics, which, in turn, may change the power required for wing motion. There are many kinematic mechanisms that bats, and other flapping animals, can use to increase aerodynamic force, e.g. increasing wingbeat frequency or amplitude. However, we do not know if there is a difference in energetic cost between these different kinematic mechanisms. To assess the relationship between mechanical power input and aerodynamic force output across different isolated kinematic parameters, we programmed a robotic bat wing to flap over a range of kinematic parameters and measured aerodynamic force and mechanical power. We systematically varied five kinematic parameters: wingbeat frequency, wingbeat amplitude, stroke plane angle, downstroke ratio, and wing folding. Kinematic values were based on observed values from free flying Cynopterus brachyotis, the species on which the robot was based. We describe how lift, thrust, and power change with increases in each kinematic variable. We compare the power costs associated with generating additional force through the four kinematic mechanisms controlled at the shoulder, and show that all four mechanisms require approximately the same power to generate a given force. This result suggests that no single parameter offers an energetic advantage over the others. Finally, we show that retracting the wing during upstroke reduces power requirements for flapping and increases net lift production, but decreases net thrust production. These results compare well with studies performed on C. brachyotis, offering insight into natural flight kinematics. (paper)

  19. Factors Affecting Embryogenic Callus Production and Plant Regeneration in Anther Culture of Bupleurum chinense

    Institute of Scientific and Technical Information of China (English)

    YANG Cheng-min; ZHAO Yu-kai; WEI Jian-he; ZHAO Li-zi; SUI Chun; ZHANG Zheng; CUI Lu-ying

    2011-01-01

    Objective To evaluate the influences of the genotypes,anther developmental stages,and cultural conditions on the efficiency of embryogenic callus induction and plant regeneration in the anthers culture of Bupleurum chinense.Methods The different effects such as four genotypes,plant growth regulators,and temperature condition were compared in the experiments.The histological study was performed with the process of the anther culture.Results The highest inducing rate of embryogenic calli were achieved for the genotypes Zhongcaiyihao(ZCYH),Z4,and Z5 at the early-to middle-uninucleate stages,except for genotype ZPM1 at the tetrad stage.Cold pretreatment increased the production of the embryogenic callus,in which 4-day cold pretreatment improved the production of embryogenic callus from 0% to 2.2% and 5.0% for genotypes ZPM1 and ZCYH,respectively.No embryogenic callus was induced in the medium containing less than 0.75 mg/L 2,4-dichlorophenoxyacetic acid(2,4-D).The highest regeneration rate (34.6%)was obtained in 1/2 MS salts regeneration medium supplemented with 0.1 mg/L 6-benzylmaminopurine (BA).The low concentration of BA was able to promote the embryogenic callus formation and subsequent plantlet regeneration via somatic embryogenesis.Chromosome counting of regenerated plantlets showed mostly diploid plant (2n = 12)with only one haploid plant(n = 6).Because of the low rate of microspore embryo formation,we only tracked the process of embryogenesis from the connective tissue,instead of microspore by histological observations.Conclusion This study establishes an efficient system for embryogenic callus induction and plant regeneration system.This is the first report on the haploid plantlet through the anther culture orB.chinense.

  20. Stable inheritance of plasmid R1 requires two different loci.

    OpenAIRE

    Gerdes, K; Larsen, J E; Molin, S

    1985-01-01

    The largest EcoRI fragment from plasmid R1 mediates a stability phenotype which is required to ensure the stable inheritance of this low-copy-number plasmid. When covalently linked to small, unstable R1 derivatives, this fragment makes the plasmids as stable as the wild-type R1 plasmid. A genetic analysis showed that two independently acting stabilization functions are encoded by this EcoRI fragment, both of which have the potential of partial stabilization of mini-R1 plasmids. The two loci a...

  1. DNA restriction-modification systems mediate plasmid maintenance.

    OpenAIRE

    Kulakauskas, S; Lubys, A; Ehrlich, S. D.

    1995-01-01

    Two plasmid-carried restriction-modification (R-M) systems, EcoRI (from pMB1 of Escherichia coli) and Bsp6I (from pXH13 of Bacillus sp. strain RFL6), enhance plasmid segregational stability in E. coli and Bacillus subtilis, respectively. Inactivation of the endonuclease or the presence of the methylase in trans abolish the stabilizing activity of the R-M systems. We propose that R-M systems mediate plasmid segregational stability by postsegregational killing of plasmid-free cells. Plasmid-enc...

  2. Blastocyst rate of in vitro embryo production in sheep is affected by season.

    Science.gov (United States)

    Mara, L; Sanna, D; Casu, S; Dattena, M; Muñoz, I M Mayorga

    2014-08-01

    It has been reported that the number and quality of in vitro produced embryos is season related. This study was conducted to assess the effect of season on cleavage, blastocyst and lambing rates of in vitro produced ovine embryos during 3 years of collection data. Ovaries of Sarda sheep were collected from a slaughterhouse. In total, 5035 oocytes were recovered and matured in TCM-199 with 4 mg/ml bovine serum albumin (BSA), 100 μM cysteamine, 0.3 mM Na pyruvate, 0.1 UI/ml recombinant follicle-stimulating hormone (r-FSH), 0.1 UI/ml recombinant luteinising hormone (r-LH), and 1 μg/ml estradiol-17β. Matured oocytes were fertilized with fresh semen in synthetic oviductal fluid (SOF) with 20% heat inactivated estrous sheep serum. The presumptive zygotes were cultured for 6-7 days (blastocyst stage) in SOF medium supplemented with 1% Basel Medium Eagle (BME), 1% Minimum Essential Medium, 1 mM glutamine and 8 mg/ml fatty acid-free BSA. The embryos produced were vitrified and a total of 165 blastocysts (80 from the breeding season and 85 from the anoestrous season) were transferred in pairs into recipient ewes during the reproductive period. There were no significant differences in cleavage rates between seasons in any of the 3 years examined (84% versus 83%, 81% versus 80% and 80% versus 79%, respectively). The blastocyst rate varied significantly between seasons in 2005 and 2007 (P < 0.05), and in 2006 (P < 0.001). There were no differences in pregnancy and lambing rates between embryos during anoestrous versus during the breeding season. In conclusion, only the blastocyst rate appeared to have been affected by season, possibly due to variation in the number of developmentally competent oocytes. PMID:23458093

  3. UV-B affects photosynthesis, ROS production and motility of the freshwater flagellate, Euglena agilis Carter

    International Nuclear Information System (INIS)

    Highlights: ► We proposed a hypothesis for the UV-B protective/adaptive mechanism in Euglena agilis. After moderate levels of UV-B radiation, ROS plays a signaling role to shut down photosynthetic system for protection against harmful UV radiation. ► E. agilis exposed to excessive UV appears to become animal-like, investing all its stored energy into movement rather than into sustaining its photosynthetic machinery. ► This adaptation allows E. agilis to avoid harmful UV and seek a safe place where the organism may regain its photosynthetic capacity for survival. - Abstract: The effects of ultraviolet B (UV-B; 295–320 nm) radiation on certain vital physiological (photosynthesis), biochemical (production of reactive oxygen species – ROS) and behavioral (motility and orientation) characteristics were investigated in the unicellular photoautotroph, Euglena agilis Carter. The photosynthetic performance of E. agilis was recorded after exposure of between 15 and 60 min followed by a period of recovery lasting 6–24 h under dim light (5–10 μmol photons m−2 s−1). The maximum quantum yield of PS II (Fv/Fm) was reduced to 65% and 14% of initial values immediately following 15 and 30 min UV-B exposure, but recovered to 100 and 86% of the initials, respectively. Values of rETRmax in E. agilis exposed to 15 min UV-B were similar to those of the initials, but a 30 min UV exposure resulted in 75% reduction of rETRmax with only a 43% recovery as compared with the initial after 24 h recovery. After a 60 min UV-B exposure, there were no Chl a fluorescence signals, and hence no Fv/Fm or rETRmax. A UV dose-dependent increase in DCFH-DA fluorescence was found in E. agilis cells, reflecting an increase in ROS production. After exposures to UV-B for between 15 and 60 min, the percentages of motile cells in the population decreased to 76, 39 and 15%, respectively. Following 24 h in dim light, the percentage of motile cells increased to between 66% and 95% of the initial

  4. Maize production as affected by sowing date, plant density and row spacing in the Bolivian Amazon

    Directory of Open Access Journals (Sweden)

    Paolo Casini

    2012-12-01

    Full Text Available The traditional cropping system widespread in the Department of Pando (Bolivian Amazon is the slash and burn methodology. The main crops sowed soon after the slash are maize, rice, cassava and common beans. Two separate field experiments (carried out in 2008-2009 were carried out to determine the agronomic responses of maize to sowing date, plant population and row width. For the first experiment a split-plot design was used. Maize cultivar (Bayo Blando and Perla Pandino was considered as main plots and the date of sowing as subplots. For the second experiment a split-split-plot design was used. Row spacing (0.5, 0.7 and 0.9 m was considered as main plot, maize cultivar (Cubano Amrarillo and Perla Pandino as subplots, and plant density (5.0, 7.5 and 10 plant m-2 as sub-subplots. A significant reduction of grain yield was observed as the date of sowing (DS delayied. Yield reduction of the second DS compared to the first, was 85 and 45% for Perla Pandino and Bayo Blando. The importance of plant density as a function of the correct row spacing is clearly shown. With the row spacing in use in the considered area (0.9 m and with the narrowest (0.5 m, the best yields were obtained with 10 plants m-2 (5.5 t ha-1. The following conclusions can be drawn from the present study: 1. A delay in the sowing date for maize by 15-20 days (compared to sowing ??immediately after the cutting of the virgin forest or the secondary forest strongly reduces grain production. The cultivar Perla Pandino was the most susceptible with a reduction of 85%. Late sowing of maize (mais de socorro, is suitable only if intercropped with other crops in order to protect the soil from erosion. Traditionally, rice and cassava are intercropped with maize, even if common beans or a legume cover crop would be more advisable. 2. The density of maize may be increased up until 10 m-2 in order to achieve the most productive results by using row spacings of 0.5 e 0.9 m, respectively

  5. Hydrodynamic Shear Stress Affects Cell Growth and Metabolite Production by Medicinal Mushroom Ganoderma lucidum

    Institute of Scientific and Technical Information of China (English)

    龚海刚; 钟建江

    2005-01-01

    By investigating the shear effect on submerged cultivation of a traditional Chinese medicinal herb Ganoderma lucidum, a relatively high cell concentration of 13.8 g·L-1 by dry mass was obtained in bioreactor at an impeller tip speed (ITS) of 0.51m·s-1. At an ITS of 0.51,1.02 and 1.53m·s-1, a maximal production titer of intracellular polysaccharide was 2.64, 2.20 and 2.28g·L-1 and that of ganoderic acid was 306, 299 and 273g·L-1, respectively. Under these ITSs, the maximal mean projected area of dispersed hypheue was 3.70, 2.54 and 2.13 × 104μm2, and that of pellets was 0.91, 0.67 and 0.55 mm2, respectively. The information obtained is useful for efficient submerged cultivation of mushrooms on a large scale.

  6. Radio-transmitters do not affect seasonal productivity of female Golden-winged Warblers

    Science.gov (United States)

    Streby, Henry M.; Peterson, Sean M.; Gesmundo, Callie; Johnson, Michael K.; Fish, Alexander C.; Lehman, Justin A.; Andersen, David E.

    2013-01-01

    Investigating the potential effects of handling and marking techniques on study animals is important for correct interpretation of research results and to effect progress in data-collection methods. Few investigators have compared the reproductive output of radio-tagged and non-radio-tagged songbirds, and no one to date has examined the possible effect of radio-tagging adult songbirds on the survival of their fledglings. In 2011 and 2012, we compared several parameters of reproductive output of two groups of female Golden-winged Warblers (Vermivora chrysoptera) breeding in Minnesota, including 45 females with radio-transmitters and 73 females we did not capture, handle, or mark. We found no difference between groups in clutch sizes, hatching success, brood sizes, length of incubation and nestling stages, fledging success, number of fledglings, or survival of fledglings to independence. Thus, radio-tags had no measurable impact on the productivity of female Golden-winged Warblers. Our results build upon previous studies where investigators have reported no effects of radio-tagging on the breeding parameters of songbirds by also demonstrating no effect of radio-tagging through the post-fledging period and, therefore, the entire breeding season.

  7. Elevated Atmospheric CO2 Affects Ectomycorrhizal Species Abundance and Increases Sporocarp Production under Field Conditions

    Directory of Open Access Journals (Sweden)

    Douglas L. Godbold

    2015-04-01

    Full Text Available Anthropogenic activities during the last century have increased levels of atmospheric CO2. Forest net primary productivity increases in response to elevated CO2, altering the quantity and quality of carbon supplied to the rhizosphere. Ectomycorrhizal fungi form obligate symbiotic associations with the fine roots of trees that mediate improved scavenging for nutrients in exchange for a carbohydrate supply. Understanding how the community structure of ectomycorrhizal fungi is altered by climate change is important to further our understanding of ecosystem function. Betula pendula and Fagus sylvatica were grown in an elevated CO2 atmosphere delivered using free air carbon dioxide enrichment (FACE under field conditions in the U.K., and Picea abies was grown under elevated CO2 in glass domes in the Czech Republic. We used morphotyping and sequencing of the internal transcribed spacer region of the fungal ribosomal operon to study ectomycorrhizal community structure. Under FACE, un-colonised roots tips increased in abundance for Fagus sylvatica, and during 2006, sporocarp biomass of Peziza badia significantly increased. In domes, ectomycorrhizal community composition shifted from short-distance and smooth medium-distance to contact exploration types. Supply and competition for carbon belowground can influence ectomycorrhizal community structure with the potential to alter ecosystem function.

  8. Plasmid-borne cadmium resistant determinants are associated with the susceptibility of Listeria monocytogenes to bacteriophage.

    Science.gov (United States)

    Zhang, Hui; Zhou, Yan; Bao, Hongduo; Zhang, Lili; Wang, Ran; Zhou, Xiaohui

    2015-03-01

    Listeria monocytogenes is an intracellular pathogen causing gastroenteritis, central nervous system infections and abortions. Chromosomal virulence determinants have been extensively investigated. However, the function of genes encoded by plasmids in L. monocytogenes has not been fully understood. In this study, we determined the prevalence and molecular profile of plasmids in food isolates of L. monocytogenes and examined the contribution of four plasmid-borne cadmium-resistant genes to the susceptibility of L. monocytogenes to bacteriophage infection. The results showed that plasmids were isolated from 55% (11/20) of the isolates and the plasmids exhibited 10 molecular types as determined by restriction enzyme digestion. Furthermore, 65% and 15% of the isolates were tolerant to cadmium and benzalkonium chloride (BC), respectively. All the BC-resistant isolates were resistant to cadmium. The prevalence of predicted cadmium resistance determinants (cadA1, cadA2, cadA3 and cadC) was determined and the results showed that cadA1 (35%) in isolates of serotypes 1/2a and 1/2b was much more prevalent than cadC (15%). As expected, both cadA and cadC mutants had reduced resistance to cadmium, while the resistance to BC was not significantly affected. Interestingly, both cadA and cadC mutants showed significantly higher susceptibility against L. monocytogenes phage LipG2-5 and FWLLm3 compared with the wide-type strain. Based on these results, we concluded that plasmids from L. monocytogenes encoded important functional determinants that are not only associated with cadmium resistance, but also phage susceptibility. PMID:25721472

  9. Rapid and inexpensive method for isolating plasmid DNA

    International Nuclear Information System (INIS)

    A small-scale and economical method for isolating plasmid DNA from bacteria is described. The method provides DNA of suitable quality for most DNA manipulation techniques. This DNA can be used for restriction endonuclease digestion, southern blot hybridization, nick translation and end labeling of DNA probes, Polymerase Chain Reaction (PCR) -based techniques, transformation, DNA cycle-sequencing, and Chain-termination method for DNA sequencing. The entire procedure is adapted to 1.5 ml microfuge tubes and takes approximately 30 mins. The DNA isolated by this method has the same purity produced by CTAB and cesium chloride precipitation and purification procedures respectively. The two previous methods require many hours to obtain the final product and require the use of very expensive equipment as ultracentrifuge. This method is well suited for the isolation of plasmid DNA from a large number of bacterial samples and in a very short time and low cost in laboratories where chemicals, expensive equipment and finance are limited factors in conducting molecular research. (authors). 11refs. 11refs

  10. Nucleotide sequences of Herpes Simplex Virus type 1 (HSV-1) affecting virus entry, cell fusion, and production of glycoprotein gB (VP7)

    Energy Technology Data Exchange (ETDEWEB)

    DeLuca, N.; Bzik, D.J.; Bond, V.C.; Person, S.; Snipes, W.

    1982-10-30

    The tsB5 strain of Herpes Simplex Virus type 1 (HSV-1) contains at least two mutations; one mutation specifies the syncytial phenotype and the other confers temperature sensitivity for virus growth. These functions are known to be located between the prototypic map coordinates 0.30 and 0.42. In this study it was demonstrated that tsB5 enters human embryonic lung (HEL) cells more rapidly than KOS, another strain of HSV-1. The EcoRI restriction fragment F from the KOS strain (map coordinates 0.315 to 0.421) was mapped with eight restriction endonucleases, and 16 recombinant plasmids were constructed which contained varying portions of the KOS genome. Recombinant viruses were generated by marker-rescue and marker-transfer cotransfection procedures, using intact DNA from one strain and a recombinant plasmid containing DNA from the other strain. The region of the crossover between the two nonisogenic strains was inferred by the identification of restriction sites in the recombinants that were characteristic of the parental strains. The recombinants were subjected to phenotypic analysis. Syncytium formation, rate of virus entry, and the production of gB were all separable by the crossovers that produced the recombinants. The KOS sequences which rescue the syncytial phenotype of tsB5 were localized to 1.5 kb (map coordinates 0.345 to 0.355), and the temperature-sensitive mutation was localized to 1.2 kb (0.360 to 0.368), giving an average separation between the mutations of 2.5 kb on the 150-kb genome. DNA sequences that specify a functional domain for virus entry were localized to the nucleotide sequences between the two mutations. All three functions could be encoded by the virus gene specifying the gB glycoprotein.

  11. Mapping QTLs on BTA6 affecting milk production traits in a Chinese Holstein population

    Institute of Scientific and Technical Information of China (English)

    CHEN Huiyong; LI Hejun; QIU Xiaotian; ZHANG Qin; WANG Chunkao; SHU Juan; MEI Gui; YIN Cengceng; HU Fang; XU Jingjing; GONG Weijia

    2005-01-01

    A Chinese Holstein population with daughter design was analyzed using 14 microsatellites covering a map distance of 55.7 cM on chromosome 6 to fine map QTL for five milk production traits. 26 paternal half-sib families with 2356 daughters were involved. Two different approaches, linear regression approach and variance component approach, were employed, with a one-QTL model and two-QTL model fitted. With a one-QTL model, the linear regression approach revealed a QTL near BMS470 with effects on milk yield, fat yield, protein yield, and fat percentage, and another QTL near BMS2460 for protein percentage. The variance component approach confirmed the results of linear regression approach for the three yield traits, with the exception that the QTL for fat yield was mapped to a different position near BMS1242. The 95% confidence intervals resulted from linear regression, obtained by bootstrapping, were generally large, ranging from 31 to 53 cM, whereas the variance component approach revealed very small confidence intervals, calculated by LOD drop-off method, for the three yield traits, only 4―5 cM. With a two-QTL model, both approaches provided strong evidence for the existence of two QTLs for the three yield traits. Along with the QTLs identified in one-QTL model analyses, the linear regression approach revealed a second QTL near BP7 with effects on all the three yield traits, whereas the variance component approach located the second QTL near ILSS035, BMS470, and BP7 for the three traits, respectively.

  12. Modeling sRNA-regulated Plasmid Maintenance

    CERN Document Server

    Gong, Chen Chris

    2016-01-01

    We study a theoretical model for the toxin-antitoxin (hok/sok) mechanism for plasmid maintenance in bacteria. Toxin-antitoxin systems enforce the maintenance of a plasmid through post-segregational killing of cells that have lost the plasmid. Key to their function is the tight regulation of expression of a protein toxin by an sRNA antitoxin. Here, we focus on the nonlinear nature of the regulatory circuit dynamics of the toxin-antitoxin mechanism. The mechanism relies on a transient increase in protein concentration rather than on the steady state of the genetic circuit. Through a systematic analysis of the parameter dependence of this transient increase, we confirm some known design features of this system and identify new ones: for an efficient toxin-antitoxin mechanism, the synthesis rate of the toxin's mRNA template should be lower that of the sRNA antitoxin, the mRNA template should be more stable than the sRNA antitoxin, and the mRNA-sRNA complex should be more stable than the sRNA antitoxin. Moreover, ...

  13. Identification of a splicing coactivator gene that affects the production of ochratoxin a in Aspergillus carbonarius

    Directory of Open Access Journals (Sweden)

    Lígia Uno Lunardi

    2009-11-01

    Full Text Available Ochratoxin A is a mycotoxin produced by some fungi species. Among them, Aspergillus carbonarius is considered a powerful producer. Genes involved in the ochratoxin A biosynthesis pathway have been identified in some producer species. However, there are few studies that purpose to identify these genes in A. carbonarius. The use of insertion mutants to identify genes associated with certain properties has been increased in the literature. In this work, the region of T-DNA integration was investigated in one A. carbonarius ochratoxin-defective mutant previously obtained by Agrobacterium tumefaciens-mediated transformation, in order to find an association between interrupted gene and the biosynthesis of ochratoxin A. The integration occurred in a gene that possibly encodes a splicing coactivator protein. The analysis of the relative expression of the splicing coativator gene from A. carbonarius wild type strain in four different media showed high correlation between the transcript levels and the ochratoxin A production.A ocratoxina A é uma micotoxina frequentemente encontrada em uma grande variedade de produtos alimentares e apresenta efeitos nefrotóxicos e potencial carcinogênico para animais e humanos. É naturalmente produzida por algumas espécies fúngicas, como Aspergillus carbonarius, que é considerado um potente produtor. Apesar disso, o número de estudos que visam identificar genes que são essenciais para a biossíntese de ocratoxina em A. carbonarius é ainda reduzido. Um mutante de A. carbonarius com baixa produção de ocratoxina A previamente obtido por transformação mediada por Agrobacterium tumefaciens foi investigado com o objetivo de encontrar uma associação entre o gene interrompido e a biossíntese desta micotoxina. Os resultados mostraram a ocorrência de uma junção não exata entre o T-DNA e o DNA genômico do fungo durante o evento de integração. A integração do T-DNA no genoma do mutante T188 provocou dele

  14. Milk production traits of beef cows as affected by horn fly count and sire breed type.

    Science.gov (United States)

    Mays, A R; Brown, M A; von Tunglen, D L; Rosenkrans, C F

    2014-03-01

    Horn fly infestations negatively impact economic traits of beef cattle. Our objective was to determine the impact of horn flies on beef cattle milk yield and quality. Cows (n = 53) were derived from Brangus dams and sired by Bonsmara (n = 7), Brangus (n = 13), Charolais (n = 8), Gelbvieh (n = 5), Hereford (n = 12), and Romosinuano (n = 8) bulls. Horn fly counts and estimates of milk yield and quality were recorded monthly from May through October on individual cows. Data for milk yield and quality and horn fly count were analyzed by mixed model least squares using a linear model including sire breed, cow in sire breed, month, and month × sire breed. Effects of horn fly count on milk yield and quality were estimated by analysis of covariance using log horn fly count and log horn fly count × sire breed. Horn fly counts varied by month (P Brangus sired cows was intermediate (7.28, 7.00, and 7.06 kg/d, respectively). Regression of milk yield on fly count differed (P Brangus, Charolais, Hereford, and Romosinuano sired cows, and coefficients for Bonsmara sired cows were reduced (P Brangus sired cows. Increases in log fly count were associated with decreases (P < 0.05) in milk fat, solids-not-fat, and milk urea nitrogen. Milk yield was reduced (P < 0.05) by increased fly numbers depending on month of lactation and interaction with log horn fly count. In May, June, and July milk yield was reduced 0.72, 0.68, and 0.71 kg/d per unit increase in log horn fly count. Our results indicate that horn fly infestations reduce milk yield and quality of spring-calving beef cows depending on sire breed and month of lactation. Development of sustainable beef production systems may include selecting breed types whose milk yield and quality is less influenced by horn flies, allowing for better expression of genetic potential for milk yield in nutritionally challenging environments. PMID:24492544

  15. Changing nutrient stoichiometry affects phytoplankton production, DOP accumulation and dinitrogen fixation - a mesocosm experiment in the eastern tropical North Atlantic

    Science.gov (United States)

    Meyer, J.; Löscher, C. R.; Neulinger, S. C.; Reichel, A. F.; Loginova, A.; Borchard, C.; Schmitz, R. A.; Hauss, H.; Kiko, R.; Riebesell, U.

    2016-02-01

    Ocean deoxygenation due to climate change may alter redox-sensitive nutrient cycles in the marine environment. The productive eastern tropical North Atlantic (ETNA) upwelling region may be particularly affected when the relatively moderate oxygen minimum zone (OMZ) deoxygenates further and microbially driven nitrogen (N) loss processes are promoted. Consequently, water masses with a low nitrogen to phosphorus (N : P) ratio could reach the euphotic layer, possibly influencing primary production in those waters. Previous mesocosm studies in the oligotrophic Atlantic Ocean identified nitrate availability as a control of primary production, while a possible co-limitation of nitrate and phosphate could not be ruled out. To better understand the impact of changing N : P ratios on primary production and N2 fixation in the ETNA surface ocean, we conducted land-based mesocosm experiments with natural plankton communities and applied a broad range of N : P ratios (2.67-48). Silicic acid was supplied at 15 µmol L-1 in all mesocosms. We monitored nutrient drawdown, biomass accumulation and nitrogen fixation in response to variable nutrient stoichiometry. Our results confirmed nitrate to be the key factor determining primary production. We found that excess phosphate was channeled through particulate organic matter (POP) into the dissolved organic matter (DOP) pool. In mesocosms with low inorganic phosphate availability, DOP was utilized while N2 fixation increased, suggesting a link between those two processes. Interestingly this observation was most pronounced in mesocosms where nitrate was still available, indicating that bioavailable N does not necessarily suppress N2 fixation. We observed a shift from a mixed cyanobacteria-proteobacteria dominated active diazotrophic community towards a diatom-diazotrophic association of the Richelia-Rhizosolenia symbiosis. We hypothesize that a potential change in nutrient stoichiometry in the ETNA might lead to a general shift within

  16. Phenotypes and gene expression profiles of Saccharopolyspora erythraea rifampicin-resistant (rif mutants affected in erythromycin production

    Directory of Open Access Journals (Sweden)

    Bicciato Silvio

    2009-03-01

    Full Text Available Abstract Background There is evidence from previous works that bacterial secondary metabolism may be stimulated by genetic manipulation of RNA polymerase (RNAP. In this study we have used rifampicin selection as a strategy to genetically improve the erythromycin producer Saccharopolyspora erythraea. Results Spontaneous rifampicin-resistant (rif mutants were isolated from the parental strain NRRL2338 and two rif mutations mapping within rpoB, S444F and Q426R, were characterized. With respect to the parental strain, S444F mutants exhibited higher respiratory performance and up to four-fold higher final erythromycin yields; in contrast, Q426R mutants were slow-growing, developmental-defective and severely impaired in erythromycin production. DNA microarray analysis demonstrated that these rif mutations deeply changed the transcriptional profile of S. erythraea. The expression of genes coding for key enzymes of carbon (and energy and nitrogen central metabolism was dramatically altered in turn affecting the flux of metabolites through erythromycin feeder pathways. In particular, the valine catabolic pathway that supplies propionyl-CoA for biosynthesis of the erythromycin precursor 6-deoxyerythronolide B was strongly up-regulated in the S444F mutants, while the expression of the biosynthetic gene cluster of erythromycin (ery was not significantly affected. In contrast, the ery cluster was down-regulated ( Conclusion Rifampicin selection is a simple and reliable tool to investigate novel links between primary and secondary metabolism and morphological differentiation in S. erythraea and to improve erythromycin production. At the same time genome-wide analysis of expression profiles using DNA microarrays allowed information to be gained about the mechanisms underlying the stimulatory/inhibitory effects of the rif mutations on erythromycin production.

  17. Determination of Plasmid Segregational Stability in a Growing Bacterial Population.

    Science.gov (United States)

    Kramer, M Gabriela

    2016-01-01

    Bacterial plasmids are extensively used as cloning vectors for a number of genes for academic and commercial purposes. Moreover, attenuated bacteria carrying recombinant plasmids expressing genes with anti-tumor activity have shown promising therapeutic results in animal models of cancer. Equitable plasmid distribution between daughter cells during cell division, i.e., plasmid segregational stability, depends on many factors, including the plasmid copy number, its replication mechanism, the levels of recombinant gene expression, the type of bacterial host, and the metabolic burden associated with all these factors. Plasmid vectors usually code for antibiotic-resistant functions, and, in order to enrich the culture with bacteria containing plasmids, antibiotic selective pressure is commonly used to eliminate plasmid-free segregants from the growing population. However, administration of antibiotics can be inconvenient for many industrial and therapeutic applications. Extensive ongoing research is being carried out to develop stably-inherited plasmid vectors. Here, I present an easy and precise method for determining the kinetics of plasmid loss or maintenance for every ten generations of bacterial growth in culture. PMID:26846807

  18. Plasmid transfer between bacteria in soil microcosms and the field

    Directory of Open Access Journals (Sweden)

    Eric Smit

    1997-01-01

    Full Text Available In ibis review factors influencing conjugal plasmid transfer between bacteria and the possible role of naturally occurring selftransmissible plasmide for the dissemination of recombinant DNA in soil will be discussed. In microcosm studies, plasmid transfer between various species of introduced bacteria has been detected. Moreover, plamid transfer to indigenous soil micoorganisms was observed. Soil is an oligotrophic environment and plasmid transfer occurred mainly under conditions which were nutritionally favourable for bacteria, such as in the plant rhizosphere and in the presence of clay minerais or added nutrients. Mobilizable plasmids, lacking the ability to transfer themselves, have been reported to be transferred in the presence of selftransmissible plasmids. A study comparing conjugal transfer in microcosme with those in the field revealed that the transfer rates found in microcosme and in the field were similar. Transfer of chromosomal DNA by plasmid RP4 could only be shown on filters and was not observed in soil. Transfer of plasmids carrying biodegradative genes appeared to be favoured in the presence of the compound that can be degraded. Evidence was found for the presence of naturally-occurring selftransmissible plasmids in bacteria in the rhizosphere which could mobilize recombinant plasmids.

  19. Isolation, Sequence Analysis, and Comparison of Two Plasmids (28 and 29 Kilobases) from the Biomining Bacterium Leptospirillum ferrooxidans ATCC 49879

    OpenAIRE

    Coram, Nicolette J.; van Zyl, Leonardo J.; Rawlings, Douglas E.

    2005-01-01

    Two plasmids, of 28,878 bp and 28,012 bp, were isolated from Leptospirillum ferrooxidans ATCC 49879. Altogether, a total of 67 open reading frames (ORFs) were identified on both plasmids, of which 32 had predicted products with high homology to proteins of known function, while 11 ORFs had predicted products with homology to previously identified proteins of unknown function. Twenty-four ORFs had products with no homologues in the GenBank/NCBI database. An analysis of the ORFs and other featu...

  20. Characterization of toxin plasmids in Clostridium perfringens type C isolates.

    Science.gov (United States)

    Gurjar, Abhijit; Li, Jihong; McClane, Bruce A

    2010-11-01

    Clostridium perfringens type C isolates cause enteritis necroticans in humans or necrotizing enteritis and enterotoxemia in domestic animals. Type C isolates always produce alpha toxin and beta toxin but often produce additional toxins, e.g., beta2 toxin or enterotoxin. Since plasmid carriage of toxin-encoding genes has not been systematically investigated for type C isolates, the current study used Southern blot hybridization of pulsed-field gels to test whether several toxin genes are plasmid borne among a collection of type C isolates. Those analyses revealed that the surveyed type C isolates carry their beta toxin-encoding gene (cpb) on plasmids ranging in size from ∼65 to ∼110 kb. When present in these type C isolates, the beta2 toxin gene localized to plasmids distinct from the cpb plasmid. However, some enterotoxin-positive type C isolates appeared to carry their enterotoxin-encoding cpe gene on a cpb plasmid. The tpeL gene encoding the large clostridial cytotoxin was localized to the cpb plasmids of some cpe-negative type C isolates. The cpb plasmids in most surveyed isolates were found to carry both IS1151 sequences and the tcp genes, which can mediate conjugative C. perfringens plasmid transfer. A dcm gene, which is often present near C. perfringens plasmid-borne toxin genes, was identified upstream of the cpb gene in many type C isolates. Overlapping PCR analyses suggested that the toxin-encoding plasmids of the surveyed type C isolates differ from the cpe plasmids of type A isolates. These findings provide new insight into plasmids of proven or potential importance for type C virulence. PMID:20823204

  1. Translational control and differential RNA decay are key elements regulating postsegregational expression of the killer protein encoded by the parB locus of plasmid R1

    DEFF Research Database (Denmark)

    Gerdes, K; Helin, K; Christensen, O W;

    1988-01-01

    The parB locus of plasmid R1, which mediates plasmid stability via postsegregational killing of plasmid-free cells, encodes two genes, hok and sok. The hok gene product is a potent cell-killing protein. The hok gene is regulated at the translational level by the sok gene-encoded repressor, a small...... anti-sense RNA complementary to the hok mRNA. The hok mRNA is extraordinarily stable, while the sok RNA decays rapidly. The mechanism of postsegregational killing is explained by the following model; the sok RNA molecule rapidly disappears in cells that have lost a parB-carrying plasmid, leading to...... translation of the stable hok mRNA. Consequently, the Hok protein is synthesized and killing of the plasmid-free cell follows....

  2. Chloride stress triggers maturation and negatively affects the postharvest quality of persimmon fruit. Involvement of calyx ethylene production.

    Science.gov (United States)

    Besada, Cristina; Gil, Rebeca; Bonet, Luis; Quiñones, Ana; Intrigliolo, Diego; Salvador, Alejandra

    2016-03-01

    In recent years many hectares planted with persimmon trees in E Spain have been diagnosed with chloride toxicity. An effect of this abiotic stress on fruit quality has been reported in different crops. However, the impact of chloride stress on persimmon fruit quality is unknown. The harvest and postharvest quality of persimmons harvested from trees that manifest different intensities of chloride toxicity foliar symptoms was evaluated herein. Our results revealed that fruits from trees under chloride stress conditions underwent chloride accumulation in the calyx, which was more marked the greater the salt stress intensity trees were exposed to. Increased chloride concentrations in the calyx stimulated ethylene production in this tissue. In the fruits affected by slight and moderate chloride stress, calyx ethylene production accelerated the maturity process, as reflected by increased fruit colour and diminished fruit firmness. In the fruits under severe chloride stress, the high ethylene levels in the calyx triggered autocatalytic ethylene production in other fruit tissues, which led fruit maturity to drastically advance. In these fruits effectiveness of CO2 deastringency treatment was not complete and fruit softening enhanced during the postharvest period. Moreover, chloride stress conditions had a marked effect on reducing fruit weight, even in slightly stressed trees. PMID:26807935

  3. Evaluation of factors affecting cucumber- and- tomato greenhouse farmers\\\\\\' attitudes toward healthy crops production in Isfahan Township

    Directory of Open Access Journals (Sweden)

    A. Sandoghi

    2015-08-01

    Full Text Available The aim of this study was to evaluate the factors affecting the attitude of cucumber and tomato greenhouse farmers toward production of healthy crops in Isfahan County. Data were collected on a sample of 110 farmers through face-to-face interviews based on a comprehensive structured questionnaire. Validity and reliability of the questionnaire was initially evaluated on a pre-test study respectively by using Kaiser-Meyer-Olkin (KMO criteria and Cronbach’s alpha coefficient. Factors influencing farmers' attitudes were assessed by using linear regression model and ordinary least squares (OLS estimation. Results indicated that most greenhouse farmers (85% had moderate and positive attitudes about production of healthy crops and only 15% had negative attitudes. In addition, economic and technical supports by the government, awareness of the related organizations, marketing and media have a positive effect on the farmers' attitudes toward production of healthy crops and there is a less positive attitude with increasing the age of farmers.

  4. Molecular characterization of "plasmid-free" antibiotic-resistant Haemophilus influenzae.

    OpenAIRE

    Roberts, M C; Smith, A. L.

    1980-01-01

    We examined 14 multiresistant and 8 ampicillin- or tetracycline-resistant Haemophilus influenzae isolates and 4 ampicillin-resistant H. parainfluenzae isolates for plasmid deoxyribonucleic acid. Sixteen strains carried plasmids. Both "plasmid-free" and plasmid-carrying isolates transferred the antibiotic resistance by conjugation. All transconjugants carried plasmid deoxyribonucleic acid, suggesting that the apparent plasmid-free strains contained R plasmids encoding for antibiotic resistance.

  5. Diversity and stability of Plasmids from glycopeptide-resistant Enterococcus faecium (GRE) isolated from pigs in Denmark

    DEFF Research Database (Denmark)

    Hasman, Henrik; Villadsen, A.G.; Aarestrup, Frank Møller

    2005-01-01

    was seen at the end of the 7-year period, coinciding with the ban in 1998 of the macrolide tylosin as growth promoter for pig production. The stability of the plasmid in its original host was compared with stability of the same plasmid in BM4105RF, when both strains were maintained in liquid cultures......In this paper, we examine the plasmid variation between a subset of unrelated GRE isolated from pigs in Denmark between 1995 and 2001 (five from each of the years). The isolates were tested with PFGE, plasmid RFLP, and subsequently Southern blotting with an IS1216V probe. Of the 35 isolates, 31...... belonged to the same PFGE type (type 1), and the last four belonged to a completely different PFGE type (type II). All 35 isolates contained the same type of large plasmid (approximate size of 150-200 kb), which could be divided into eight different variant types (V0 to V7). Most variance among the plasmid...

  6. Damage to plasmid DNA induced by low energy carbon ions

    International Nuclear Information System (INIS)

    The damage induced in supercoiled plasmid DNA molecules by 1-6 keV carbon ions has been investigated as a function of ion exposure, energy and charge state. The production of short linear fragments through multiple double strand breaks has been demonstrated and exponential exposure responses for each of the topoisomers have been found. The cross section for the loss of supercoiling was calculated to be (2.2 ± 0.5) x 10-14 cm2 for 2 keV C+ ions. For singly charged carbon ions, increased damage was observed with increasing ion energy. In the case of 2 keV doubly charged ions, the damage was greater than for singly charged ions of the same energy. These observations demonstrate that ion induced damage is a function of both the kinetic and potential energies of the ion

  7. Regional Algal Biofuel Production Potential in the Coterminous United States as Affected by Resource Availability Trade-offs

    Energy Technology Data Exchange (ETDEWEB)

    Venteris, Erik R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Skaggs, Richard [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wigmosta, Mark S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Coleman, Andre M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-03-15

    The warm sunny climate and unoccupied arid lands in the American southwest are favorable factors for algae cultivation. However, additional resources affect the overall viability of specific sites and regions. We investigated the tradeoffs between growth rate, water, and CO2 availability and costs for two strains: N. salina and Chlorella sp. We conducted site selection exercises (~88,000 US sites) to produce 21 billion gallons yr-1 (BGY) of renewable diesel (RD). Experimental trials from the National Alliance for Advanced Biofuels and Bio-Products (NAABB) team informed the growth model of our Biomass Assessment Tool (BAT). We simulated RD production by both lipid extraction and hydrothermal liquefaction. Sites were prioritized by the net value of biofuel minus water and flue gas costs. Water cost models for N. salina were based on seawater and high salinity groundwater and for Chlorella, fresh and brackish groundwater. CO2 costs were based on a flue gas delivery model. Selections constrained by production and water were concentrated along the Gulf of Mexico and southeast Atlantic coasts due to high growth rates and low water costs. Adding flue gas constraints increased the spatial distribution, but the majority of sites remained in the southeast. The 21 BGY target required ~3.8 million hectares of mainly forest (41.3%) and pasture (35.7%). Exclusion in favor of barren and scrub lands forced most production to the southwestern US, but with increased water consumption (5.7 times) and decreased economic efficiency (-38%).

  8. Remote sensing for assessing the zone of benefit where deep drains improve productivity of land affected by shallow saline groundwater.

    Science.gov (United States)

    Kobryn, H T; Lantzke, R; Bell, R; Admiraal, R

    2015-03-01

    The installation of deep drains is an engineering approach to remediate land salinised by the influence of shallow groundwater. It is a costly treatment and its economic viability is, in part, dependent on the lateral extent to which the drain increases biological productivity by lowering water tables and soil salinity (referred to as the drains' zone of benefit). Such zones may be determined by assessing the biological productivity response of adjacent vegetation over time. We tested a multi-temporal satellite remote sensing method to analyse temporal and spatial changes in vegetation condition surrounding deep drainage sites at five locations in the Western Australian wheatbelt affected by dryland salinity-Morawa, Pithara, Beacon, Narembeen and Dumbleyung. Vegetation condition as a surrogate for biological productivity was assessed by Normalised Difference Vegetation Index (NDVI) during the peak growing season. Analysis was at the site scale within a 1000 m buffer zone from the drains. There was clear evidence of NDVI increasing with elevation, slope and distance from the drain. After accounting for elevation, slope and distance from the drain, there was a significant increase in NDVI across the five locations after installation of deep drains. Changes in NDVI after drainage were broadly consistent with measured changes at each site in groundwater levels after installation of the deep drains. However, this study assessed the lateral extent of benefit for biological productivity and gave a measure of the area of benefit along the entire length of the drain. The method demonstrated the utility of spring NDVI images for rapid and relatively simple assessment of the change in site condition after implementation of drainage, but approaches for further improvement of the procedure were identified. PMID:25481499

  9. Fertilization Affects Biomass Production of Suaeda salsa and Soil Organic Carbon Pool in East Coastal Region of China

    Institute of Scientific and Technical Information of China (English)

    MENG Qing-feng; YANG Jing-song; YAO Rong-jiang; LIU Guang-ming; YU Shi-peng

    2013-01-01

    Land use practice significantly affects soil properties. Soil is a major sink for atmospheric carbon, and soil organic carbon (SOC) is considered as an essential indicator of soil quality. The objective of this study was to assess the effects of N and P applied to Suaeda salsa on biomass production, SOC concentration, labile organic carbon (LOC) concentration, SOC pool and carbon management index (CMI) as well as the effect of the land use practice on soil quality of coastal tidal lands in east coastal region of China. The study provided relevant references for coastal exploitation, tidal land management and related study in other countries and regions. The field experiment was laid out in a randomized complete block design, consisting of four N-fertilization rates (0 (N0), 60 (N1), 120 (N2) and 180 kg ha-1 (N3)), three P-fertilization rates (0 (P0), 70 (P1) and 105 kg ha-1 (P2)) and bare land without vegetation. N and P applied to S. salsa on coastal tidal lands significantly affected biomass production (above-ground biomass and roots), bulk density (ρb), available N and P, SOC, LOC, SOC pool and CMI. Using statistical analysis, significantly interactions in N and P were observed for biomass production and the dominant factor for S. salsa production was N in continuous 2-yr experiments. There were no significant interactions between N and P for SOC concentration, LOC concentration and SOC pool. However, significant interaction was obtained for CMI at the 0-20 cm depth and N played a dominant role in the variation of CMI. There were significant improvements for soil measured attributes and parameters, which suggested that increasing the rates of N and P significantly decreasedρb at the 0-20 cm depth and increased available N and P, SOC, LOC, SOC pool as well as CMI at both the 0-20 and 20-40 cm depth, respectively. By correlation analysis, there were significantly positive correlations between biomass (above-ground biomass and roots) and SOC as well as LOC in

  10. Characterization of a Large, Stable, High-Copy-Number Streptomyces Plasmid That Requires Stability and Transfer Functions for Heterologous Polyketide Overproduction▿

    OpenAIRE

    Fong, Ryan; Hu, Zhihao; Hutchinson, C. Richard; Huang, Jianqiang; Cohen, Stanley; Kao, Camilla

    2006-01-01

    A major limitation to improving small-molecule pharmaceutical production in streptomycetes is the inability of high-copy-number plasmids to tolerate large biosynthetic gene cluster inserts. A recent finding has overcome this barrier. In 2003, Hu et al. discovered a stable, high-copy-number, 81-kb plasmid that significantly elevated production of the polyketide precursor to the antibiotic erythromycin in a heterologous Streptomyces host (J. Ind. Microbiol. Biotechnol. 30:516-522, 2003). Here, ...

  11. Production of biochar out of organic urban waste to amend salt affected soils in the basin of Mexico

    Science.gov (United States)

    Chavez Garcia, Elizabeth; Siebe, Christina

    2016-04-01

    Biochar is widely recognized as an efficient tool for carbon sequestration and soil fertility. The understanding of its chemical and physical properties, strongly related to the biomass and production conditions, is central to identify the most suitable application of biochar. On the other hand, salt affected soils reduce the value and productivity of extensive areas worldwide. One feasible option to recover them is to add organic amendments, which improve water holding capacity and increase sorption sites for cations as sodium. The former lake Texcoco in the basin of Mexico has been a key area for the control of surface run-off and air quality of Mexico City. However, the high concentrations of soluble salts in their soils do not allow the development of a vegetation cover that protects the soil from wind erosion, being the latter the main cause of poor air quality in the metropolitan area during the dry season. On the other hand, the population of the city produces daily 2000 t of organic urban wastes, which are currently composted. Thus, we tested if either compost or biochar made out of urban organic waste can improve the salt affected soils of former lake Texcoco to grow grass and avoid wind erosion. We examined the physico-chemical properties of biochar produced from urban organic waste under pyrolysis conditions. We also set up a field experiment to evaluate the addition of these amendments into the saline soils of Texcoco. Our preliminary analyses show biochar yield was ca. 40%, it was mainly alkaline (pH: 8-10), with a moderate salt content (electrical conductivity: 0.5-3 mS/cm). We show also results of the initial phase of the field experiment in which we monitor the electrical conductivity, pH, water content, water tension and soil GHG fluxes on small plots amended with either biochar or compost in three different doses.

  12. Soil organic carbon fractions in a Vertisol under irrigated cotton production as affected by burning and incorporating cotton stubble

    International Nuclear Information System (INIS)

    The contribution of cotton stubble to the soil organic matter content of Vertisols under cotton production is not well understood. A 3-year experiment was conducted at the Australian Cotton Research Institute to study the effects of burning and incorporating cotton stubble on the recovery of fertiliser nitrogen (N), lint yield, and organic matter levels. This study reports on the changes in soil organic matter fractions as affected by burning and incorporating cotton stubble into the soil. Soil samples collected at the start and end of the 3-year experiment were analysed for total carbon (CT), total N (NT), and δ13C (a measure of 13C/12C isotopic ratios). Labile carbon (CL) was determined by ease of oxidation and non-labile carbon (CNL) was calculated as the difference between CT and CL. Based on the changes in CT, CL, and CNL, a carbon management index (CMI) was calculated. Further analyses were made for total polysaccharides (PT), labile polysaccharides (PL), and light fraction C (LF-C). Stubble management did not significantly affect the NT content of the soil. After 3 years, the stubble-incorporated plots had a significantly higher content of CT, CL, and polysaccharides. Incorporation of stubble into the soil increased the CMI by 41%, whereas burning decreased the CMI by 6%. The amount of LF-C obtained after 3 years in the stubble-incorporated soil was almost double that obtained in the stubble-burnt soil. It was concluded that for sustainable management of soil organic matter in the Vertisols used for cotton production, stubble produced in the system should be incorporated instead of burnt. Copyright (1998) CSIRO Publishing

  13. Safety and efficacy of DNA vaccines: Plasmids vs. minicircles

    OpenAIRE

    Stenler, Sofia; Blomberg, Pontus; Smith, Ci Edvard

    2014-01-01

    While DNA vaccination using plasmid vectors is highly attractive, there is a need for further vector optimization regarding safety, stability, and efficiency. In this commentary, we review the minicircle vector (MC), which is an entity devoid of plasmid bacterial sequences, as an alternative to the traditional plasmid construct. The commentary highlights the recent discovery by Stenler et al. (2014) that the small size of an MC enables improved resistance to the shearing forces associated wit...

  14. Pathogenomics of the Virulence Plasmids of Escherichia coli

    OpenAIRE

    Johnson, Timothy J.; Lisa K. Nolan

    2009-01-01

    Summary: Bacterial plasmids are self-replicating, extrachromosomal elements that are key agents of change in microbial populations. They promote the dissemination of a variety of traits, including virulence, enhanced fitness, resistance to antimicrobial agents, and metabolism of rare substances. Escherichia coli, perhaps the most studied of microorganisms, has been found to possess a variety of plasmid types. Included among these are plasmids associated with virulence. Several types of E. col...

  15. Identification of plasmid partition function in coryneform bacteria.

    OpenAIRE

    Kurusu, Y; Satoh, Y.; Inui, M.; Kohama, K; Kobayashi, M.; Terasawa, M.; Yukawa, H

    1991-01-01

    We have identified and characterized a partition function that is required for stable maintenance of plasmids in the coryneform bacteria Brevibacterium flavum MJ233 and Corynebacterium glutamicum ATCC 31831. This function is localized to a HindIII-NspV fragment (673 bp) adjacent to the replication region of the plasmid, named pBY503, from Brevibacterium stationis IFO 12144. The function was independent of copy number control and was not associated directly with plasmid replication functions. ...

  16. Streamlined Purification of Plasmid DNA From Prokaryotic Cultures

    OpenAIRE

    Pueschel, Laura; Li, Hongshan; Hymes, Matthew

    2011-01-01

    We describe the complete process of AcroPrep Advance Filter Plates for 96 plasmid preparations, starting from prokaryotic culture and ending with high purity DNA. Based on multi-well filtration for bacterial lysate clearance and DNA purification, this method creates a streamlined process for plasmid preparation. Filter plates containing silica-based media can easily be processed by vacuum filtration or centrifuge to yield appreciable quantities of plasmid DNA. Quantitative analyses determine ...

  17. Comparative genetic organization of incompatibility group P degradative plasmids.

    OpenAIRE

    Burlage, R S; Bemis, L A; Layton, A C; Sayler, G. S.; Larimer, F

    1990-01-01

    Plasmids that encode genes for the degradation of recalcitrant compounds are often examined only for characteristics of the degradative pathways and ignore regions that are necessary for plasmid replication, incompatibility, and conjugation. If these characteristics were known, then the mobility of the catabolic genes between species could be predicted and different catabolic pathways might be combined to alter substrate range. Two catabolic plasmids, pSS50 and pSS60, isolated from chlorobiph...

  18. Effects of Halides on Plasmid-Mediated Silver Resistance in Escherichia coli

    OpenAIRE

    Gupta, Amit; Maynes, Maria; Silver, Simon

    1998-01-01

    Silver resistance of sensitive Escherichia coli J53 and resistance plasmid-containing J53(pMG101) was affected by halides in the growth medium. The effects of halides on Ag+ resistance were measured with AgNO3 and silver sulfadiazine, both on agar and in liquid. Low concentrations of chloride made the differences in MICs between sensitive and resistant strains larger. High concentrations of halides increased the sensitivities of both strains to Ag+.

  19. Bacteriologic and plasmid analysis of etiologic agents of conjunctivitis in Lagos, Nigeria

    OpenAIRE

    Iwalokun, Bamidele Abiodun; Oluwadun, Afolabi; Akinsinde, Kehinde Adewale; Niemogha, Mary Theressa; Nwaokorie, Fransisca Obiageri

    2011-01-01

    Background Conjunctivitis, an inflammation of the conjunctiva, is one of the most common eye problems affecting all age groups in Nigeria. A better understanding of its epidemiology and the antibiotic susceptibility of etiologic bacterial agents is crucial for the initiation of preventive and therapeutic measures. This study determined the distribution and patterns of bacterial infections in Nigerian patients with conjunctivitis. Antibiotic resistance patterns and the plasmid profiles of thes...

  20. Expression of the Salmonella virulence plasmid gene spvB in cultured macrophages and nonphagocytic cells.

    OpenAIRE

    Fierer, J.; Eckmann, L; Fang, F.; Pfeifer, C; Finlay, B B; Guiney, D

    1993-01-01

    Certain serotypes of salmonellae carry virulence plasmids that greatly enhance the pathogenicity of these bacteria in experimentally infected mice. This phenotype is largely attributable to the 8-kb spv regulon. However, spv genes are not expressed while bacteria grow in vitro. We now show that spvB, which is required for virulence, is expressed rapidly after Salmonella dublin is ingested by cultured J774 and murine peritoneal macrophages and that expression is not affected by the alkalinizat...

  1. The economics of research and development : how research and development capital affects production and markets and is affected by tax incentives

    OpenAIRE

    Shah, Anwar; DEC

    1994-01-01

    Certain themes and findings emerge from the authors analysis of key relationships between research and development (R&D) and other factors. Among them: (1) R&D capital and the structure of production: (a) R&D capital facilitates the mapping of technological possibilities into economic opportunities. (b) R&D takes time to accumulate and uses up scarce resources. The adjustment process from project initiation to product and process development typically takes three to five years. (c) The margin...

  2. Construction of a eukaryotic expression plasmid of Humanin*

    OpenAIRE

    Luo, Ben-yan; Chen, Xiang-ming; Tang, Min; Chen, Feng; Chen, Zhi

    2004-01-01

    Objective: To construct a eukaryotic expression plasmid pcDNA3.1(-)-Humanin. Methods: The recombinant plasmid pGEMEX-1-Humanin was digested with restriction endonucleases BamH I and Hind III and the Humanin gene fragments, about 100 bp length, were obtained. Then the Humanin gene fragments were inserted into eukaryotic expression vector pcDNA3.1(-) and the recombinant plasmids pcDNA3.1(-)-Humanin were identified by sequencing. Results: Recombinant plasmid DNA successfully produced a band whic...

  3. Characterization of a plasmid from moderately halophilic eubacteria

    OpenAIRE

    Fernández Castillo, Rosario; Vargas, C.; Nieto Gutiérrez, Joaquín José; Ventosa Ucero, Antonio; Ruiz Berraquero, Francisco

    1992-01-01

    A plasmid has been isolated for the first time from moderately halophilic eubacteria. Halomonas elongata, Halomonrrs halmphila, Deleya halophila and Vibrio costkola were found to harbour an 11.5 kbp plasmid (pMH1). The plasmid was isolated and characterized after transformation into Escherichia coh'JM101 cells. A restriction map was constructed, and unique restriction sites for EcoRI, EcoRV and ClaI were detected. The occurrence of such a plasmid in the original halophilic strains was confirm...

  4. Characterization of Chlamydia trachomatis Plasmid-Encoded Open Reading Frames

    OpenAIRE

    Gong, Siqi; Yang, Zhangsheng; Lei, Lei; Shen, Li; Zhong, Guangming

    2013-01-01

    The recent success in transformation of Chlamydia trachomatis represents a major advancement in Chlamydia research. Plasmid-free C. trachomatis serovar L2 organisms can be transformed with chlamydial plasmid-based shuttle vectors pGFP::SW2 and pBRCT. Deletion of plasmid genes coding for Pgp1 to Pgp8 in pBRCT led to the identification of Pgp1, -2, -6, and -8 as plasmid maintenance factors; Pgp4 as a transcriptional regulator of chlamydial virulence-associated gene expression; and Pgp3, -5, and...

  5. Plasmid P1 replication: negative control by repeated DNA sequences.

    OpenAIRE

    Chattoraj, D; Cordes, K.; Abeles, A

    1984-01-01

    The incompatibility locus, incA, of the unit-copy plasmid P1 is contained within a fragment that is essentially a set of nine 19-base-pair repeats. One or more copies of the fragment destabilizes the plasmid when present in trans. Here we show that extra copies of incA interfere with plasmid DNA replication and that a deletion of most of incA increases plasmid copy number. Thus, incA is not essential for replication but is required for its control. When cloned in a high-copy-number vector, pi...

  6. Identification of plasmid partition function in coryneform bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Kurusu, Yasurou; Satoh, Yukie; Inui, Masayuki; Kohama, Keiko; Kobayashi, Miki; Terasawa, Masato; Yukawa, Hideaki (Mitsubishi Petrochemical Co., Ltd., Ibaraki (Japan))

    1991-03-01

    The authors have identified and characterized a partition function that is required for stable maintenance of plasmids in the coryneform bacteria Brevibacterium flavum MJ233 and Corynebacterium glutamicum ATCC 31831. This function is localized to a HindIII-NspV fragment (673 bp) adjacent to the replication region of the plasmid, named pBY503, from Brevibacterium stationis IFO 12144. The function was independent of copy number control and was not associated directly with plasmid replication functions. This fragment was able to stabilize the unstable plasmids in cis but not in trans.

  7. Degradative Plasmid and Heavy Metal Resistance Plasmid Naturally Coexist in Phenol and Cyanide Assimilating Bacteria

    OpenAIRE

    Bahig E.  Deeb; Abdullah D. Altalhi

    2009-01-01

    Problem statement: Heavy metals are known to be powerful inhibitors of xenobiotics biodegradation activities. Alleviation the inhibitory effect of these metals on the phenol biodegradation activities in presence of heavy metals resistant plasmid was investigated. Approach: Combination of genetic systems of degradation of xenobiotic compound and heavy metal resistance was one of the approaches to the creation of polyfunctional strains for bioremediation of s...

  8. Photonic plasmid stability of transformed Salmonella Typhimurium: A comparison of three unique plasmids

    Directory of Open Access Journals (Sweden)

    Lay Donald

    2009-07-01

    Full Text Available Abstract Background Acquiring a highly stable photonic plasmid in transformed Salmonella Typhimurium for use in biophotonic studies of bacterial tracking in vivo is critical to experimental paradigm development. The objective of this study was to determine stability of transformed Salmonella Typhimurium (S. typh-lux using three different plasmids and characterize their respective photonic properties. Results In presence of ampicillin (AMP, S. typh-lux with pCGLS-1, pAK1-lux and pXEN-1 plasmids exhibited 100% photon-emitting colonies over a 10-d study period. Photon emitters of S. typh-lux with pCGLS-1, pAK1-lux and pXEN-1 without AMP selection decreased over time (P 7 to 1 × 109 CFU, P 0.05; although photonic emissions across a range of bacterial concentrations were not different (1 × 104 to 1 × 106 CFU, P > 0.05. For very low density bacterial concentrations imaged in 96 well plates photonic emissions were positively correlated with bacterial concentration (P 3 to 1 × 105 CFU low to high were different in the 96-well plate format (P Conclusion These data characterize photon stability properties for S. typh-lux transformed with three different photon generating plasmids that may facilitate real-time Salmonella tracking using in vivo or in situ biophotonic paradigms.

  9. Photonic Plasmid Stability of Transformed Salmonella Typhimurium: A Comparison of Three Unique Plasmids

    Science.gov (United States)

    Background: Acquiring a highly stable photonic plasmid in transformed Salmonella Typhimurium for use in biophotonic studies of bacterial tracking in vivo is critical to experimental paradigm development. The objective of this study was to determine stability of transformed Salmonella Typhimurium (S....

  10. Photonic plasmid stability of transformed Salmonella typhimurium: A comparison of three unique plasmids

    Science.gov (United States)

    Acquiring a highly stable photonic plasmid in transformed Salmonella typhimurium for use in biophotonic studies of bacterial tracking in vivo is critical to experimental paradigm development. The objective of this study was to determine stability of transformed Salmonella typhimurium (S. typh-lux) u...

  11. Bacterial Mitosis: ParM of Plasmid R1 Moves Plasmid DNA by an Actin-like Insertional Polymerization Mechanism

    DEFF Research Database (Denmark)

    Møller-Jensen, Jakob; Borch, Jonas; Dam, Mette;

    2003-01-01

    Bacterial DNA segregation takes place in an active and ordered fashion. In the case of Escherichia coli plasmid R1, the partitioning system (par) separates paired plasmid copies and moves them to opposite cell poles. Here we address the mechanism by which the three components of the R1 par system...... act together to generate the force required for plasmid movement during segregation. ParR protein binds cooperatively to the centromeric parC DNA region, thereby forming a complex that interacts with the filament-forming actin-like ParM protein in an ATP-dependent manner, suggesting that plasmid...... movement is powered by insertional polymerization of ParM. Consistently, we find that segregating plasmids are positioned at the ends of extending ParM filaments. Thus, the process of R1 plasmid segregation in E. coli appears to be mechanistically analogous to the actin-based motility operating...

  12. Culture Conditions affect the Category and Production of Ubiquinones in a Recombinant Escherichia Coli with an Exogenous Decaprenyl Diphosphate Synthase

    Directory of Open Access Journals (Sweden)

    Jiazhou Li

    2013-06-01

    Full Text Available Ubiquinones (UQ are important electron transporters and play lot of important roles in most organisms. In different species, UQ was classified to be UQ-6, 7, 8, 9, 10 according to their polyprenyl side chain length. The side chain’s length is determined by the enzyme named Poly-Prenyl diphosphate synthases (PPPS. Bacteria are usually reconstructed to producing UQ-10 used in human’s food additive, medicine or cosmetics, such as using decaprenyl Diphosphate Synthase (DPS gene from R. radiobacter to substitute E.coli’s octaprenyl diphosphate synthase gene , just like E. coli BL21 (△ispB::ddsA used in this study. It is interesting that not only in these reconstructed bacteria, but in human-being, DPS can synthesize UQ-9 besides UQ-10. The mechanism of this phenomenon is still unknown. In this study, the effects of culture conditions, including the temperature, dissolved oxygen, pH and culture medium, on the DPS characteristics in E. coli BL21 (△ispB::ddsA were examined. Results show that temperature greatly affects the ratio of UQ-9/UQ-10, but not the total ubiquinone’s production. Increasing dissolved oxygen and protein concentration in culture medium can promote total ubiquinone’s production, but not the ratio of UQ-9/UQ-10. These results may give reference for UQ-10’s industrial produce and the mechanism of these conditions’ effect on DPS will be discussed.

  13. Culture Conditions Affect the Category and Production of Ubiquinones in a Recombinant Escherichia Coli with an Exogenous Decaprenyl Diphosphate Synthase

    Directory of Open Access Journals (Sweden)

    Jiazhou Li

    2013-09-01

    Full Text Available Ubiquinones (UQ are important electron transporters and play lot of important roles in most organisms. In different species, UQ was classified to be UQ-6, 7, 8, 9, 10 according to their polyprenyl side chain length. The side chain’s length is determined by the enzyme named Poly-Prenyl diphosphate Synthases (PPPS. Bacteria are usually reconstructed to producing UQ-10 used in human’s food additive, medicine or cosmetics, such as using decaprenyl Diphosphate Synthase (DPS gene from R. radiobacter to substitute E. coli’s octaprenyl diphosphate synthase gene, just like BL21 (∆ispB::ddsA used in this study. It is interesting that not only in these reconstructed bacteria, but in human-being, DPS can synthesize UQ-9 besides UQ-10. The mechanism of this phenomenon is still unknown. In this study, the effects of culture conditions, including the temperature, dissolved oxygen, pH and culture medium, on the DPS characteristics in BL21 (∆ispB::ddsA were examined. Results show that temperature greatly affects the ratio of UQ-9/UQ-10, but not the total ubiquinone’s production. Increasing dissolved oxygen and protein concentration in culture medium can promote total ubiquinone’s production, but not the ratio of UQ-9/UQ-10. These results may give reference for UQ-10’s industrial produce and the mechanism of these conditions’ effect on DPS will be discussed.

  14. Nodulation, dry matter production and N2 fixation by fababean and chickpea as affected by soil moisture and potassium fertilizer

    International Nuclear Information System (INIS)

    The impact of three rates of K-fertilizer (0, 75, and 150 kg K2O/ha)on nodulation, dry matter production and N2 fixation by fababean (Vicia faba L.) and chickpea (Cirer arietinum L.) was evaluated in a pot experiment. The plants were subjected to three soil moisture regimes (low, 45-50%; moderate, 55-60% and high 75-80% of field capacity). 15N-isotope dilution method was employed to evaluate N2 fixation using a non-fixing chickpea genotype as a reference crop. Water restriction drastically affected dry matter production, nodulation and N2 fixation by both plant species. The negative effect of water stress on %N2 fixed was more prominent in chickpea (11-58%) than in fababean (68-81%) under low and high % of field capacity, respectively. Plant species differed in their response to K-fertilizer as a mean to enhance growth and overcome the stress conditions. The higher level of K fertilizer increased both dry matter production and total N2 fixed in fababean, but did not have any impact on chickpea. %N2 fixed, however, appeared to be unaffected by K fertilizer as a mean of alleviating drought stress in both plant species. Therefore, it appears that, under the experimental conditions, the beneficial effect of potassium on water-stressed fababean resulted from stimulation the growth rather than improving the N2-fixation efficiency. However, under well-watered plants, a high requirement of the symbiotic system to potassium is needed to ensure and optimal growth and N2-fixation. (author)

  15. Yield and nutritional quality of greenhouse lettuce (Lactuca sativa L. as affected by genotype and production methods

    Directory of Open Access Journals (Sweden)

    Govedarica-Lučić Aleksandra

    2014-01-01

    Full Text Available Greenhouse experiments were conducted in winter growing seasons in order to evaluate the effects of genotype and production methods on yield and nutritional quality of lettuce (Lactuca sativa L.. A three-year (2009-2011 study was conducted by randomized block system in a greenhouse without additional heating. The trial included three genotypes of lettuce (Archimedes RZ, Santoro RZ, Kibou RZ. Each row with these genotypes was exposed to the following variants of covering: control-planting on bare soil, mulching before sowing with PE-black foil, agro textile-covering plants after planting with agro textile (17 g, a combination of mulching + agro textile. Throughout of all the three years of the trial, it was continuously evidenced that the genotype “Santoro RZ” had the biggest heads and the highest yield (15.33 kg 10 m-2, which leads to conclusion that the yield of lettuce is a genotype characteristics. Moreover, the nutritional value (ascorbic acid concentration has shown that, depending on the method of production, in average, the combination of mulching + agro textile (26.77 mg 100 g-1 had the highest content while the control variant had significantly lower vitamin C content (21.10 mg 100 g-1. The three-year researches have shown that the production method and genotype significantly affect the nitrate content. An average nitrate content was 2196.33 mg kg-1 on the control variant, and 2526.24 mg kg-1 on agro textile. Leafy lettuce of genotyp „Kibou RZ“ had lower nitrate content (2176.85 mg kg-1 compared to „Archimedes RZ“ (2843.05 mg kg-1 and „Santoro RZ“ (2221.37 mg kg-1. However nitrate concentration in all treatments remained within the European Union’s permissible levels.

  16. Degradative Plasmid and Heavy Metal Resistance Plasmid Naturally Coexist in Phenol and Cyanide Assimilating Bacteria

    Directory of Open Access Journals (Sweden)

    Bahig E.  Deeb

    2009-01-01

    Full Text Available Problem statement: Heavy metals are known to be powerful inhibitors of xenobiotics biodegradation activities. Alleviation the inhibitory effect of these metals on the phenol biodegradation activities in presence of heavy metals resistant plasmid was investigated. Approach: Combination of genetic systems of degradation of xenobiotic compound and heavy metal resistance was one of the approaches to the creation of polyfunctional strains for bioremediation of soil after co-contamination with organic pollutants and heavy metals. Results: A bacterial strain Pseudomonas putida PhCN (pPhCN1, pPhCN2 had been obtained. This bacterium contained two plasmids, a 120 Kb catabolic plasmid that encode for breakdown of phenol (pPhCN1 and pPhCN2 plasmid (100 Kb that code for cadmium and copper resistant. Cyanide assimilation by this bacterium was encoded by chromosomal genes. The inhibitory effect of cadmium (Cd2+ or copper (Cu2+ on the degradation of phenol and cyanide by P. putida strains PhCN and PhCN1 (contained pPhCN1 were investigated. The resistant strain PhCN showed high ability to degrade phenol and cyanide in presence of Cd2+ or Cu2+ comparing with the sensitive strain PhCN1. In addition, Cd2+ or Cu2+ was also found to exert a strong inhibitory effect on the C23O dioxygenase enzyme activity in the presence of cyanide as a nitrogen source. Conclusion: The presence of heavy metal resistance plasmid alleviated the inhibitory effect of metals on the phenol and cyanide assimilation by resistant strain.

  17. Construction of a recombinant bacterial plasmid containing DNA sequences for a mouse embryonic globin chain.

    Science.gov (United States)

    Fantoni, A; Bozzoni, I; Ullu, E; Farace, M G

    1979-01-01

    Messenger RNAs for mouse embryonic globins were purified from yolk sac derived eyrthroid cells in mouse fetuses. Double stranded DNAs complementary to these messengers were synthesized and blunt end ligated to a EcoRI digested and DNA polymerase I repaired pBR322 plasmid. Of the ampicillin resistant transformants, one contained a plasmid with globin-specific cDNA. The inserted sequence is about 350 base pairs long. It contains one restriction site for EcoRI and one restriction site for HinfI about 170 and 80 base pairs from one end. The insert is not cleaved by HindIII, HindII, BamHI, PstI, SalI, AvaI, TaqI, HpaII, BglI. A mixture of purified messengers coding for alpha chains and for x, y and z embryonic chains was incubated with the recombinant plasmid and the hybridized messenger was translated in a mRNA depleted reticulocyte lysate protein synthesizing system. The product of translation was identified as a z chain by carboxymethylcellulose cromatography. The recombinant plasmid is named "pBR322-egz" after embryonic globin z. Images PMID:493112

  18. Construction of a recombinant bacterial plasmid containing DNA sequences for a mouse embryonic globin chain.

    Science.gov (United States)

    Fantoni, A; Bozzoni, I; Ullu, E; Farace, M G

    1979-08-10

    Messenger RNAs for mouse embryonic globins were purified from yolk sac derived eyrthroid cells in mouse fetuses. Double stranded DNAs complementary to these messengers were synthesized and blunt end ligated to a EcoRI digested and DNA polymerase I repaired pBR322 plasmid. Of the ampicillin resistant transformants, one contained a plasmid with globin-specific cDNA. The inserted sequence is about 350 base pairs long. It contains one restriction site for EcoRI and one restriction site for HinfI about 170 and 80 base pairs from one end. The insert is not cleaved by HindIII, HindII, BamHI, PstI, SalI, AvaI, TaqI, HpaII, BglI. A mixture of purified messengers coding for alpha chains and for x, y and z embryonic chains was incubated with the recombinant plasmid and the hybridized messenger was translated in a mRNA depleted reticulocyte lysate protein synthesizing system. The product of translation was identified as a z chain by carboxymethylcellulose cromatography. The recombinant plasmid is named "pBR322-egz" after embryonic globin z. PMID:493112

  19. Mutations in an antisense RNA, involved in the replication control of a repABC plasmid, that disrupt plasmid incompatibility and mediate plasmid speciation.

    Science.gov (United States)

    Rivera-Urbalejo, América; Pérez-Oseguera, Ángeles; Carreón-Rodríguez, Ofelia E; Cevallos, Miguel A

    2015-03-01

    The maintenance of large plasmid in a wide variety of alpha-proteobacteria depends on the repABC replication/segregation unit. The intergenic repB-repC region of these plasmids encodes a countertranscribed RNA (ctRNA) that modulates the transcription/translation rate of RepC, the initiator protein. The ctRNA acts as a strong incompatibility factor when expressed in trans. We followed a site directed mutagenesis approach to map those sequences of the ctRNA that are required for plasmid incompatibility and for plasmid replication control. We found that the first three nucleotides of the 5'-end of the ctRNA are essential for interactions with its target RNA. We also found that stretches of 4-5 nucleotides of non-complementarity within the first 10 nucleotides of the left arm of the ctRNA and the target RNA are sufficient to avoid plasmid incompatibility. Additionally, miniplasmid derivatives expressing ctRNAs with mutations in the 5' end or small deletions in the ctRNA are capable of controlling their own replication and coexisting with the parental plasmid. We suggest that a mechanism that could have a crucial role in the speciation process of repABC plasmids is to accumulate enough changes in this small region of the ctRNA gene to disrupt heteroduplex formation between the target RNA of one plasmid and the ctRNA of the other. Plasmids carrying these changes will not have defects in their maintenance. PMID:25644116

  20. Foot-and-Mouth Disease Virus neutralizing antibodies production induced by pcDNA3 and Sindbis virus based plasmid encoding FMDV P1-2A3C3D in swine.

    OpenAIRE

    Dory, Daniel; Rémond, Michelle; Béven, Véronique; Cariolet, Roland; Zientara, Stephan; Jestin, André

    2009-01-01

    International audience DNA vaccination against Foot-and-Mouth Disease Virus (FMDV) is an attractive and alternative strategy to the use of classical inactivated viral vaccines. The injection of a pcDNA3.1-based DNA vaccine encoding for FMDV P1-2A3C3D and GM-CSF proteins had previously been shown to induce the production of neutralizing antibodies against FMDV and partially protect swine against an experimental challenge. Based on the induction of FMDV humoral immune responses, the aim of t...

  1. Two Different Tetracycline Resistance Mechanisms, Plasmid-Carried tet(L) and Chromosomally Located Transposon-Associated tet(M), Coexist in Lactobacillus sakei Rits 9▿

    Science.gov (United States)

    Ammor, Mohammed Salim; Gueimonde, Miguel; Danielsen, Morten; Zagorec, Monique; van Hoek, Angela H. A. M.; de los Reyes-Gavilán, Clara G.; Mayo, Baltasar; Margolles, Abelardo

    2008-01-01

    Lactobacillus sakei is extensively used as functional starter culture in fermented meat products. One of the safety criteria of a starter culture is the absence of potentially transferable antibiotic resistance determinants. However, tetracycline-resistant L. sakei strains have already been observed. In this paper, we show that tetracycline resistance in L. sakei Rits 9, a strain isolated from Italian Sola cheese made from raw milk, is mediated by a transposon-associated tet(M) gene coding for a ribosomal protection protein and a plasmid-carried tet(L) gene coding for a tetracycline efflux pump. pLS55, the 5-kb plasmid carrying the tet(L) gene, is highly similar to the pMA67 plasmid recently described for Paenibacillus larvae, a species pathogenic to honeybees. pLS55 could be transferred by electroporation into the laboratory strain L. sakei 23K. While the L. sakei 23K transformant containing pLS55 displayed an intermediate tetracycline resistance level (MIC, <32 μg/ml), L. sakei Rits 9, containing both tetracycline-resistant determinants, had a MIC of <256 μg/ml, suggesting that Tet L and Tet M confer different levels of resistance in L. sakei. Remarkably, in the absence of tetracycline, a basal expression of both genes was detected for L. sakei Rits 9. In addition, subinhibitory concentrations of tetracycline affected the expression patterns of tet(M) and tet(L) in different ways: the expression of tet(M) was induced only at high tetracycline concentrations, whereas the expression of tet(L) was up-regulated at lower concentrations. This is the first time that two different mechanisms conferring resistance to tetracycline are characterized for the same strain of a lactic acid bacterium. PMID:18192429

  2. Factors affecting production of an antilisterial bacteriocin by Carnobacterium piscicola strain A9b in laboratory media and model fish systems

    DEFF Research Database (Denmark)

    Himelbloom, B.; Nilsson, Lilian; Gram, Lone

    2001-01-01

    supernatant fluid of a stationary-phase culture. Increasing concentrations of NaCl (2-7%) reduced bacteriocin production and maximum cell density of C. piscicola A9b when grown in cooked fish juice at VC. Conclusions: Media composition, inoculum level and sodium chloride concentration affected production...

  3. Environmental factors affecting productivity, indican content, and indigo yield in Polygonum tinctorium Ait., a subtropical crop grown under temperate conditions.

    Science.gov (United States)

    Angelini, Luciana G; Tozzi, Sabrina; Nassi o Di Nasso, Nicoletta

    2004-12-15

    Polygonum tinctorium Ait. is a herbaceous subtropical annual plant, belonging to the family Polygonaceae. Within the cells of its leaves P. tinctorium accumulates large amounts of a colorless glycoside, indican (indoxyl beta-d-glucoside), from which the blue dye indigo is synthesized. P. tinctorium is well-known in Japan, where it had been cultivated to produce natural indigo for textile dyeing, whereas it represents a potentially interesting new crop in Europe. To better understand the effects of environmental parameters on P. tinctorium crop production and indigo yield, field experiments were carried out in central Italy under temperate climate. Three lines were tested during the 2001 and 2002 growing seasons, and plant/leaf yields as well as indican contents were evaluated. The results showed that P. tinctorium grown in temperate climate conditions can be harvested three times a year. Yields of 82 and 120 t ha(-1) of fresh plant yield were obtained in 2001 and 2002, respectively. The contrasting weather conditions between the two years significantly affected biomass production, which was higher in the 2002 season, characterized by wet weather conditions. The cycle length from sowing to the last harvest was accomplished in 229-238 days when plants had accumulated 2017-2018 degrees C. Green leaves accounted for 40-45% by weight of fresh plant tissue and contained 11-20 g kg(-1) indican. The three lines did not significantly differ in the main productive parameters or in fresh leaf indican content (14.1 g kg(-1) mean value). Photosynthetic active radiation influences indican leaf production according to the model y = 0.0004x + 8.566 (P < 0.01, correlation coefficient = 0.818). Indican content ranged from 12 to 25 g kg(-1) of fresh leaves with PAR daily values from 10000 to 40000 mEinstein m(-2) (recorded in May and at the end of July-beginning of August, respectively). The results indicate that in nonlimiting rainfall conditions a very high indican content and a

  4. Plasmid-Encoded Tetracycline Efflux Pump Protein Alters Bacterial Stress Responses and Ecological Fitness of Acinetobacter oleivorans

    OpenAIRE

    Hong, Hyerim; Jung, Jaejoon; Park, Woojun

    2014-01-01

    Acquisition of the extracellular tetracycline (TC) resistance plasmid pAST2 affected host gene expression and phenotype in the oil-degrading soil bacterium, Acinetobacter oleivorans DR1. Whole-transcriptome profiling of DR1 cells harboring pAST2 revealed that all the plasmid genes were highly expressed under TC conditions, and the expression levels of many host chromosomal genes were modulated by the presence of pAST2. The host energy burden imposed by replication of pAST2 led to (i) lowered ...

  5. Genotypic and Phenotypic Diversity Does Not Affect Productivity and Drought Response in Competitive Stands of Trifolium repens.

    Science.gov (United States)

    Huber, Heidrun; During, Heinjo J; Bruine de Bruin, Fabienne; Vermeulen, Peter J; Anten, Niels P R

    2016-01-01

    Clonal plants can form dense canopies in which plants of different genetic origin are competing for the uptake of essential resources. The competitive relationships among these clones are likely to be affected by extreme environmental conditions, such as prolonged drought spells, which are predicted to occur more frequently due to global climate change. This, in turn, may alter characteristics of the ecological system and its associated functioning. We hypothesized that the relative success of individual clones will depend on the size of the ramets as ramets with larger leaves and longer petioles (large ramets) were predicted to have a competitive advantage in terms of increased light interception over smaller-sized ramets. Under drier conditions the relative performances of genotypes were expected to change leading to a change in genotype ranking. We also hypothesized that increased genotypic and phenotypic diversity will increase stand performance and resistance to drought. These hypotheses and the mechanisms responsible for shifts in competitive relationships were investigated by subjecting genotypes of the important pasture legume Trifolium repens to competition with either genetically identical clones, genetically different but similarly sized clones, or genetically as well as morphologically different clones under well-watered and dry conditions. Competitive relationships were affected by ramet size with large genotypes outperforming small genotypes in diverse stands in terms of biomass production. However, large genotypes also produced relatively fewer ramets than small genotypes and could not benefit in terms of clonal reproduction from competing with smaller genotypes, indicating that evolutionary shifts in genotype composition will depend on whether ramet size or ramet number is under selection. In contrast to our hypotheses, diversity did not increase stand performance under different selection regimes and genotype ranking was hardly affected by soil

  6. Genotypic and phenotypic diversity does not affect productivity and drought response in competitive stands of Trifolium repens

    Directory of Open Access Journals (Sweden)

    Heidrun eHuber

    2016-03-01

    Full Text Available Clonal plants can form dense canopies in which plants of different genetic origin are competing for the uptake of essential resources. The competitive relationships among these clones are likely to be affected by extreme environmental conditions, such as prolonged drought spells, which are predicted to occur more frequently due to global climate change. This, in turn, may alter characteristics of the ecological system and its associated functioning.We hypothesized that the relative success of individual clones will depend on the size of the ramets as ramets with larger leaves and longer petioles (large ramets were predicted to have a competitive advantage in terms of increased light interception over smaller-sized ramets. Under drier conditions the relative performances of genotypes were expected to change leading to a change in genotype ranking. We also hypothesized that increased genotypic and phenotypic diversity will increase stand performance and resistance to drought. These hypotheses and the mechanisms responsible for shifts in competitive relationships were investigated by subjecting genotypes of the important pasture legume Trifolium repens to competition with either genetically identical clones, genetically different but similarly sized clones, or genetically as well as morphologically different clones under well-watered and dry conditions.Competitive relationships were affected by ramet size with large genotypes outperforming small genotypes in diverse stands in terms of biomass production. However, large genotypes also produced relatively fewer ramets than small genotypes and could not benefit in terms of clonal reproduction from competing with smaller genotypes, indicating that evolutionary shifts in genotype composition will depend on whether ramet size or ramet number is under selection. In contrast to our hypotheses, diversity did not increase stand performance under different selection regimes and genotype ranking was hardly

  7. Construction and Application of R Prime Plasmids, Carrying Different Segments of an Octopine Ti Plasmid from Agrobacterium tumefaciens, for Complementation of vir Genes

    NARCIS (Netherlands)

    Hille, Jacques; Klasen, Ina; Schilperoort, Rob

    1982-01-01

    Several R prime plasmids have been obtained with high efficiency, by enclosing the R plasmid replicator, in an R::Ti cointegrate plasmid, between two copies of the transposon Tn1831, in the same orientation. These R primes carry different segments of an octopine Ti plasmid, and are compatible with T

  8. Exhaustive in vivo labelling of plasmid DNA with BrdU for intracellular detection in non-viral transfection of mammalian cells

    OpenAIRE

    Jérôme, Valérie; Heider, Andreas; Schallon, Anja; Freitag, Ruth

    2009-01-01

    Abstract The study of the non-viral gene delivery process at the molecular level, e.g. during the trans-fection of mammalian cells, is currently limited by difficulties to specifically detect the trans-fected plasmid DNA within the cells. Herein we describe the in vivo production of 5-bromodeoxyuridine- (5-BrdU) labelled plasmid DNA by a thymine-requiring Escherichia coli strain leading to 92 ? 15 % BrdU incorporation while minimizing plasmid structure alteration. The labelled plas...

  9. Persistence of a pKPN3-like CTX-M-15-encoding IncFIIK plasmid in a Klebsiella pneumonia ST17 host during two years of intestinal colonization.

    Directory of Open Access Journals (Sweden)

    Iren Høyland Löhr

    Full Text Available To characterize the CTX-M-15-encoding plasmid in a Klebsiella pneumoniae ST17 strain, responsible for an outbreak at a Norwegian neonatal intensive care unit and subsequent colonization of affected children for up to two years. To identify plasmid-mediated features relevant for the outbreak dynamics, and to investigate the plasmids capability of horizontal transfer, its segregational stability and plasmid-mediated fitness costs.Plasmid profiling was performed by S1-nuclease PFGE, PCR-based replicon typing and Southern blot-hybridization. The complete sequence of the CTX-M-15-encoding plasmid was obtained by 454 sequencing. Plasmid self-transferability was investigated by broth- and filter mating, segregational stability was explored by serial passage, and plasmid-conferred fitness costs were examined in pairwise head-to-head competitions and by growth rate comparisons.CTX-M-15 was encoded by a ~180 kb IncFIIK plasmid in K. pneumoniae ST17. S1-nuclease PFGE profiles of the first and the last CTX-M-15-producing K. pneumoniae isolates, recovered from the four children colonized the longest, suggested that the plasmid was stably maintained during intestinal carriage of up to two years. The DNA sequence of the pKPN3-like plasmid, pKp848CTX, uncovered a Tn3-like antibiotic resistance region and multiple heavy metal- and thermoresistance determinants. Plasmid pKp848CTX could not be transferred to Escherichia coli in vitro and we found no evidence to support horizontal plasmid transfer in vivo. Segregational plasmid loss ranging from 0.83% to 17.5% was demonstrated in evolved populations in vitro, but only minor fitness costs were associated with plasmid-carriage.Plasmid pKp848CTX encodes phenotypic traits, which may have had an impact on the fitness and survival of the K. pneumoniae ST17 strain in the outbreak setting. The antibiotic resistance plasmid pKp848CTX was stably maintained during two years of intestinal colonization, conferring negligible

  10. Homology of plasmids in strains of unicellular cyanobacteria

    NARCIS (Netherlands)

    Hondel, C.A.M.J.J. van den; Keegstra, W.; Borrias, W.E.; Arkel, G.A. van

    1979-01-01

    Six strains of unicellular cyanobacteria were examined for the presence of plasmids. Analysis of lysates of these strains by CsCl-ethidium bromide density centrifugation yielded a major chromosomal DNA band and a minor band containing covalently closed circular plasmid DNA, as shown by electron micr

  11. Plasmid-encoded copper resistance and precipitation by Mycobacterium scrofulaceum.

    OpenAIRE

    Erardi, F X; Failla, M L; Falkinham, J. O.

    1987-01-01

    A copper-tolerant Mycobacterium scrofulaceum strain was able to remove copper from culture medium by sulfate-dependent precipitation as copper sulfide. Such precipitation of copper sulfide was not observed in a derivative that lacks a 173-kilobase plasmid. In addition, the plasmid-carrying strain has a sulfate-independent copper resistance mechanism.

  12. Two novel conjugative plasmids from a single strain of Sulfolobus

    NARCIS (Netherlands)

    Erauso, G.; Stedman, K.M.; Werken, van de H.J.G.; Zillig, W.; Oost, van der J.

    2006-01-01

    Two conjugative plasmids (CPs) were isolated and characterized from the same 'Sulfolobus islandicus' strain, SOG2/4, The plasmids were separated from each other and transferred into Sulfolobus soltataricus. One has a high copy number and is not stable (pSOG1) whereas the other has a low copy number

  13. Inc A/C Plasmids in Multidrug resistant Salmonella enterica

    Science.gov (United States)

    Bacteria plasmids are fragments of extra-chromosomal double stranded deoxyribonucleic acid (DNA) that can contain a variety of genes beneficial to the survival of the host bacteria. Classification and tracking of plasmids is beneficial because they are potentially a medium of horizontal gene transf...

  14. Transformation of Bacillus subtilis by single-stranded plasmid DNA.

    OpenAIRE

    Rudolph, C F; Schmidt, B J; Saunders, C W

    1986-01-01

    The single-stranded form of a pE194-based plasmid transformed Bacillus subtilis protoplasts at least as efficiently as did the double-stranded plasmid, but the single-stranded form did not detectably transform B. subtilis competent cells.

  15. Curing of the 2 mu DNA plasmid from Saccharomyces cerevisiae.

    OpenAIRE

    Toh-e, A; Wickner, R B

    1981-01-01

    The 2 mu DNA plasmid is often eliminated from yeast cells when they are transformed with the 2 mu DNA-LEU2-pMB9 composite plasmid pJDB219. Since pJDB219 is subsequently lost with high frequency, derivatives lacking all 2 mu DNA can be prepared from any strain.

  16. Plasmid DNA induces dodecyl triethyl ammonium bromide to aggregate into vesicle

    Institute of Scientific and Technical Information of China (English)

    Xiang Mei Ran; Xia Guo; Jia Tong Ding

    2012-01-01

    Single-chained cationic surfactant dodecyl triethyl ammonium bromide and plasmid DNA together can form vesicles once the concentration of plasmid DNA reaches a critical value (Ccvc).Bigger the size of plasmid DNA,higher the value of Ccvc.

  17. Affective Urbanism

    DEFF Research Database (Denmark)

    Samson, Kristine

    , experience and consumption are all strategic design tools applied by planners and architects. Whereas urban design in former modernist planning served merely functional or political means, urban design has increasingly become an aesthetical mediator of ideologies embedded in the urban field of life forces...... capitalism not only changes urban life and its means of production, it specifically influences the way the city is designed and how it unfolds as events (Anderson & Harrison 2010) and affective, emotional production (Pile 2009). Through examples of urban design and events in the Carlsberg City in Copenhagen...... and The High Line in Chelsea, New York, the paper sets out to define and question these affective modes of production. Whether these productions are socio-material practices consisting of ludic designs (Stevens 2007), temporary architecture or art installations or evental practices consisting of...

  18. Interplay between pathogenicity island carriage, resistance profile and plasmid acquisition in uropathogenic Escherichia coli.

    Science.gov (United States)

    Calhau, Vera; Domingues, Sara; Ribeiro, Graça; Mendonça, Nuno; Da Silva, Gabriela Jorge

    2015-08-01

    This study aimed to characterize the relationship between pathogenicity islands (PAIs), single virulence genes and resistance among uropathogenic Escherichia coli, evaluating the resistance plasmid carriage fitness cost related to PAIs. For 65 urinary E. coli, antimicrobial susceptibility and extended-spectrum β-lactamase production were determined with the Vitek 2 Advanced Expert system. Phylogroup determination, detection of PAIs and virulence genes papAH, papC, sfa/foc, afa/dra, iutA, kpsMII, cnf1, eaeA, hlyA, stx1 and stx2, plasmid replicon typing and screening for plasmidic resistance determinants qnr, aac(6')-Ib-cr, qepA and bla(CTX-M) were carried out by PCR. Conjugation was performed between a donor carrying IncF, IncK and bla(CTX-M-15), and receptors carrying one to six PAIs. The relative fitness of transconjugants was estimated by pairwise competition experiments. PAI IV(536) (68 %), gene iutA (57 %) and resistance to ampicillin were the most prevalent traits. PAI I(536), PAI II(536), PAI III(536) and PAI II(J96) were exclusively associated with susceptibility to amoxicillin/clavulanic acid, cefotaxime, ceftazidime, ciprofloxacin, gentamicin and trimethoprim/sulfamethoxazole, and were more prevalent in strains susceptible to ampicillin and cefalotin. PAI IV(536), PAI II(CFT073) and PAI I(CFT073) were more prevalent among isolates showing resistance to amoxicillin/clavulanic acid, cefalotin, cefotaxime, ceftazidime and gentamicin. An inverse relationship was observed between the number of plasmids and the number of PAIs carried. Transconjugants were obtained for receptors carrying three or fewer PAIs. The mean relative fitness rates of these transconjugants were 0.87 (two PAIs), 1.00 (one PAI) and 1.09 (three PAI). The interplay between resistance, PAI carriage and fitness cost of plasmid acquisition could be considered PAI specific, and not necessarily associated with the number of PAIs. PMID:26293926

  19. Construction of a eukaryotic expression plasmid of Humanin

    Institute of Scientific and Technical Information of China (English)

    LUO Ben-yan; CHEN Xiang-ming; TANG Min; CHEN Feng; CHEN Zhi

    2005-01-01

    Objective: To construct a eukaryotic expression plasmid pcDNA3.1 (-)-Humanin. Methods: The recombinant plasm pGEMEX- 1-Humanin was digested with restriction endonucleases BamH I and Hind Ⅲ and the Humanin gene fragments, abo 100 bp length, were obtained. Then the Humanin gene fragments were inserted into eukaryotic expression vector pcDNA3.1 (-) and the recombinant plasmids pcDNA3. l(-)-Humanin were identified by sequencing. Results: Recombinant plasmid DNA succesfully produced a band which had the same size as that of the Humanin positive control. The sequence of recombinant plasmids accorded with the Humnain gene sequence. Conclusions: A eukaryotic expression plasmid of Humanin was successfully constructed.

  20. Permissiveness of soil microbial communities towards broad host range plasmids

    DEFF Research Database (Denmark)

    Klümper, Uli

    of fluorescently tagged conjugative plasmids into a soil microbial community in solid-surface filter matings under maximized cell-to-cell contact, followed by quantification of transfer events through advanced fluorescent microscopy, isolation of transconjugants through triple-gated fluorescent activated cell...... using model BHR plasmid pKJK5 introduced through the γ-proteobacterial donor E. coli. I found that the permissiveness towards plasmids was modified through stress on a taxon specific basis and cannot be generally predicted for the whole community. The response of the phylogenetic group was specific...... between phylogenetically distant groups. Finally, I extended the high-throughput method to quantify the potential of a microbial community to actively mobilize and transfer exogenous mobilizable plasmids to its indigenous members. I evaluated the transfer frequency of model plasmid RSF1010 by comparing...