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| Registros recuperados: 978 | |
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| Wang,Qinglong; ding,Yi; Liu,Li; Shi,Jiping; Sun,Junsong; Xue,Yongchang. |
| Background Escherichia coli does not produce n-butanol naturally, but can be butanologenic when related enzymes were expressed using inducible elements on plasmids. In this study we attempted to confer E. coli strain capability of automatic excretion of the chemical by employing a native anaerobic promoter. Also, a novel DNA kit was designed for PCR preparation of linear DNA fragments to perform strain modification. The kit is primarily composed of two mother vectors, co-transformation of linear DNAs into E. coli can simultaneously introduce two butanol synthetic operons into the chromosome and create two in-frame gene deletions at targeted native loci. Results E. coli strain Bw2V carries plasmid pCNA-PHC and pENA-TA, both utilizes native anaerobic... |
| Tipo: Journal article |
Palavras-chave: Anaerobic promoter; Escherichia coli; Metabolic engineering; N-Butanol; Recombination. |
| Ano: 2015 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582015000200013 |
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| Hussein,Hany; Ibrahim,Soha Farag; Kandeel,Kamal; Moawad,Hassan. |
| Biosorption experiments for Cr(VI), Cu(II), Cd(II) and Ni(II) were investigated in this study using nonliving biomass of different Pseudomonas species. The applicability of the Langmuir and Freundlich models for the different biosorbent was tested. The coefficient of determination (R²) of both models were mostly greater than 0.9. In case of Ni(II) and Cu(II), their coefficients were found to be close to one. This indicates that both models adequately describe the experimental data of the biosorption of these metals. The maximum adsorption capacity was found to be the highest for Ni followed by Cd(II), Cu(II) and Cr(VI). Whereas the Freundlich constant k in case of Cd(II) was found to be greater than the other metals. Maximum Cr(VI) removal reached around... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000100006 |
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| Vergara-Fernández,Alberto O; Quiroz,Erich F; Aroca,Germán E; Alarcón Pulido,Nelson A. |
| In this work the variation in the toluene elimination capacity of an airlift bioreactor as a function of the toluene inlet load, using compost as the support material for the microorganisms was studied. In order to evaluate the flexibility of the reactor under changing toluene load, the toluene biodegradation was measured for flows from 2.4 x 10-2 to 0.132 m³ h-1, and a concentration range from 1.4 to 0.8 g m-3. Results show a 100% removal efficiency (RE) for minor flows, however, for a flow increase of 450% the RE decreased 40%, reflecting the equipments weak flexibility in varying flows. Meanwhile the maximum elimination capacity obtained was 230 g m-3 h-1, for toluene loads of 550 g m-3 h-1, corresponding to a flow of 0.132 m³ h-1. It was found that a... |
| Tipo: Journal article |
Palavras-chave: Airlift bioreactors; Biofiltration; Bioscrubbers; Toluene. |
| Ano: 2008 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582008000400003 |
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| García-Baldenegro,Claudia Vanessa; Vargas-Arispuro,Irasema; Islas-Osuna,María; Rivera-Domínguez,Marisela; Aispuro-Hernández,Emmanuel; Martínez-Téllez,Miguel Ángel. |
| Background Plant tissues must be preserved in their collection state, especially for genome-wide expression profile studies. Lyophilization is a feasible, affordable tool when fresh tissues cannot be shipped at ultralow temperatures from their origin to the place of analysis. In this study, the total RNA quality of dormant grapevine buds (Vitis vinifera L. cv. Flame Seedless) of freeze-dried samples stored at room temperature conditions was evaluated and compared to that of cryopreserved (-80°C) grapevine buds. Results Good yield and quality of RNA were obtained from freeze-dried dormant buds stored at room temperature for 0, 3 and 6 weeks after they were lyophilized. Further experiments confirmed that the extracted total RNA could be used for actin and... |
| Tipo: Journal article |
Palavras-chave: Freeze-dried; RNA integrity number; RT-qPCR; Vitis vinifera L; Woody tissue. |
| Ano: 2015 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582015000200012 |
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| Solano Solis,Jaime; Morales Ulloa,Daniza; Anabalón Rodríguez,Leonardo. |
| Chile is considered to be a sub-center of origin for the cultivated potato, with native and introduced genetic material coexisting in the country. Thus, the different varieties present in Chiloe Island are characterized by a rich diversity of forms, sizes, colours and phenological characteristics. In the present work, the level of polymorphism and the genetic relationship were studied by means of molecular markers using the amplified fragment length polymorphism (AFLP) technique and twenty-seven morphological characters. Twenty varieties of potatoes from the Chiloe Island were analyzed. The commercial variety Desirée and one specie from the Etuberosa series, Solanum fernandezianum, collected in the Juan Fernandez Island were included as controls. A... |
| Tipo: Journal article |
Palavras-chave: Cluster analysis; Molecular markers; Solanum tuberosum ssp. tuberosum. |
| Ano: 2007 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582007000300011 |
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| Felmer D,Ricardo; Arias,María Elena. |
| Since the first successful somatic cell nuclear transfer (SCNT) experiments were carried out, a number of domestic and agriculture species have been cloned using donor cells derived from different sources and origin. However, differences in nuclear transfer efficiency both in vitro and in vivo have been generally observed. These differences may be accentuated when transgenic cell lines are used as nuclear donors in an attempt to generate transgenic cloned offspring. The present study examined the suitability of cell lines derived from 3 different fetal sources and the effects of genetic manipulation of donor fetal fibroblasts with a red fluorescent plasmid, on the in vitro developmental potential and quality of nuclear transfer derived bovine embryos. We... |
| Tipo: Journal article |
Palavras-chave: Bovine embryos; Fetal fibroblasts; Nuclear transfer; Transfected cells. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582011000300005 |
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| Petrova,Ventsislava Yankova; Rasheva,Tanya Vassileva; Kujumdzieva,Anna V.. |
| Catalase and superoxide dismutase activities have been explored in the yeast Saccharomyces cerevisiae during batchwise growth experiment. During the diauxic growth in YPD medium high Ys values were obtained (0.415 - 0.423) and correlation between the total activities of both enzymes has been found. A mitochondrial fraction from three type strains of Saccharomyces cerevisiae has been isolated. The purity of this fraction was proved through different enzyme assays: hexokinase, glucose-6-phosphate dehydrogenase, D-amino acid oxidase, isocitric lyase, succinate dehydrogenase. Then the catalase, peroxidase, Mn and Cu/Zn superoxide dismutase activities were evaluated in the mitochondrial fraction. Polyacrylamide gel electrophoresis separations allowed to... |
| Tipo: Journal article |
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| Ano: 2002 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582002000100010 |
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| Reyes-Contreras,Carolina; Vidal,Gladys. |
| Background Anaerobic digestion is a technology applied successfully to converting organic matter into biogas. However, the presence of inhibitory compounds such as antibiotics can adversely affect methane production. The aim of this study is to evaluate the toxic effect of chlortetracycline hydrochloride (CLOR) on the methanogenic bacteria. In order to study the methanogenic toxicity of CLOR, different concentrations of CLOR (10, 50, 100, 200 mg L- 1) were evaluated by methanogenic toxicity assays using three feedings. Results Maximum methane production was obtained for the assays with 10 mg CLOR L- 1, the values obtained were 277 ± 4.07; 193 ± 11.31 and 166 ± 7.07 mL for the first, second and third feedings, respectively. The average values for acetic,... |
| Tipo: Journal article |
Palavras-chave: Antibiotics; Anaerobic batch assay; Bacterial inhibition; Volatile fatty acids. |
| Ano: 2015 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582015000600010 |
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| Schiappacasse,MarÃa Cristina; Palma,Juan; Poirrier,Paola; Ruiz-Filippi,Gonzalo; Chamy,Rolando. |
| In Latin Americ a, the most accepted disposal systems for Municipal Solid Waste (MSW) are landfills, which nowadays have low rates of stabilization. The objective of this study was to develop design criteria for sanitary landfills which lead to a reduction in the stabilization times of MSW, based on experiment results obtain from a pre-pilot scale operation of two sanitary landfills (0.5 Ton), one with recirculation of leachates treated in an anaerobic digester and the other with recirculation of untreated leachates. This was complemented by another pilot scale sanitary landfill (1440 Ton) with recirculation of leaches treated in an anaerobic filter, and additionally by a computer simulation of leachate generation through the water balance of a theoretical... |
| Tipo: Journal article |
Palavras-chave: Hydrological balance; Landfill; Leachate recycle; Municipal solid waste; Stabilization. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582010000300009 |
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| Yavuz,Izzet; Aydin,Haluk; Ulku,Refik; Kaya,Sadullah; Tumen,Caner. |
| This study investigates the feasibility of a different new approach to determining the microleakage volume associated with dental restorations (Class V cavity restorated with glass ionomer cement + high copper amalgam) and the relative marginal adaptation deficiency of dog, bovine and human permanent teeth in in vitro conditions. Also researched is the appropriateness of using dog and bovine teeth in in vitro studies rather than human teeth. Our method utilizes the molecular adsorption characteristics of methylene blue. Within the framework of this study, 60 permanent teeth (20 human, 20 dogs and 20 bovine) were used. These groups were evaluated statistically, of which indicated no statistically significant differences (p > 0.05). It was also concluded... |
| Tipo: Journal article |
Palavras-chave: Dye adsorption test; Microleakage; Tooth. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582006000100003 |
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| Kalalou,Ichraq; Faid,Mohamed; Touhami Ahami,Ahmed. |
| Studies were conducted to stabilize minced meat by fermentation using mixed lactic acid bacteria cultures isolated from natural fermented foodstuffs and selected for their antimicrobial activity against some hazardous microorganisms. Fresh meat of camel purchased from the slaughterhouse of Rabat (Morocco) was minced separately with a meat mincer and supplied with 5% glucose, then inoculated with lactic acid bacteria. Microbiological analyses were carried out to determine standard plate count (SPC), staphylococci, coliforms, enterococci, and lactic acid bacteria. All analyses were determined after 1, 2, 3, 4 and 7 days during the storage. Results showed that a low pH of 4.0-4.2 can be achieved (within 3 days at 22ºC), with a drastic reduction in... |
| Tipo: Journal article |
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| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582004000300005 |
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| Donoso-Bravo,Andrés; Carballa,Marta; Ruiz- Filippi,Gonzalo; Chamy,Rolando. |
| In this work, an anaerobic sequencing batch reactor (ASBR) was operated for 8 months to treat low strength sewage with high suspended organic matter content. Three phases of operation with increasing organic loading rates (OLR) were performed: 0.4 kg COD/m³ x d (phase I), 0 .8 kg COD/m³ x d (phase II) and 1.2 kg COD/m³ x d (phase III). Adequate stability parameters (pH, total alkalinity) were obtained through all three experimental phases. During phases I and II, the removal efficiencies of organic matter (expressed as total chemical oxygen demand (COD) and total suspended solids ranged between 50-60%. However, these values decreased to 15-25% in phase III. In addition, a non-complex model, including hydrolysis, acidogenesis and methanogenesis, was applied... |
| Tipo: Journal article |
Palavras-chave: Acidogenesis; Anaerobic treatment; Hydrolysis; Low strength wastewater; Modeling. |
| Ano: 2009 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582009000300013 |
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| Oboh,Ganiyu. |
| Cassava pulp was fermented with pure strains of Saccharomyces cerevisae and two bacteria namely Lactobacillus delbruckii and Lactobacillus coryneformis for 3 days. The squeezed liquid from the fermented pulp was used to ferment cassava peels for 7 days. Analysis of the dried fermented peels revealed that there was a significant (P < 0.05) increase in the protein content of the cassava peels fermented with squeezed liquid from the inoculated cassava pulp (21.5%) when compared with the unfermented cassava peel (8.2%). Moreover, the treatment equally brought about a significant (P < 0.05) decrease in the cyanide (6.2 mg/kg) and phytate content (789.7 mg/100g) when compared with the unfermented cassava peels, which had 44.6 mg/kg cyanide and 1043.6... |
| Tipo: Journal article |
Palavras-chave: Cassava peels; Cyanide; Fermentatio; Protein. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582006000100007 |
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| Pesqueira,Julieta; García,Maria Dina; Staltari,Sebastian; Molina,Maria del Carmen. |
| High salt concentrations in soils negatively affect maize growth. Techniques such as remote hybridization and in vitro selection have been extensively used to accelerate breeding processes. In order to determine the usefulness of Tripsacum to improve salt tolerance in maize, the effects of NaCl, in vitro and in vivo, were evaluated in an intergeneric hybrid (MT) obtained from crossing Zea mays with Tripsacum dactyloides. Organogenic calli, induced from immature MT hybrid embryos, were exposed to different NaCl concentrations and the survival and regeneration percentages were calculated. Plants of the MT hybrid, obtained from the organogenic calli, were exposed to NaCl concentrations considered harmful for maize. The shoot dry weights of plants exposed to... |
| Tipo: Journal article |
Palavras-chave: Intergeneric hybrid; Plant regeneration; Organogenesis; Salinity tolerance. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582006000300022 |
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| Rekha,Rani; Alam Rizvi,Moshahid; Jaishree,Paul. |
| The aim of this study, was to design and validate 16S rRNA targeted oligonucleotide genus specific primers for amplifying the predominant members of gut flora using polymerase chain reaction. Primers were validated against human faecal samples. Gut flora of a normal individual was compared with that of two diseased individuals. Our observations showed that the genera Lactobacillus, Bacteroides, Peptococcus, Bifidobacterium, and E. coli were invariably present in all studied subjects however, the absence of butyrate producing bacteria Ruminococcus and Peptostreptococcus were significant. Presence of the members of the genus, Campylobacter in both the diseased samples were also unusual. |
| Tipo: Journal article |
Palavras-chave: 16S rRNA based primers; Anaerobic bacteria; Diarrhoea patient; Polymerase chain reaction. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582006000500005 |
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| Mahmood,Tariq; Zar,Tamkina; Saqlan Naqvi,S.M. |
| Electroporation entails brief, high intensity pulse to create transient pores in the cell membrane to facilitate the entry of exogenous macromolecules, which may otherwise be excluded. Removal of the external field leads to the resealing of the membrane electropores permitting the survival of the electrically stimulated recipient cells. Using this technique foreign deoxyribonucleic acid (DNA) has been successfully introduced into many cell types both from prokaryotes and eukaryotes. Increase in pulse voltage and length beyond a critical limit has been reported to decrease transformation efficiency, hence in this study we have investigated another strategy i.e. increase in the number of pulses at constant high voltage and pulse duration. Commonly used... |
| Tipo: Journal article |
Palavras-chave: Agrobacterium; Electroporation; Pulse number; Transformation efficiency. |
| Ano: 2008 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582008000100015 |
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| Registros recuperados: 978 | |
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