Selection of hammerhead ribozymes for optimum cleavage of interleukin 6 mRNA.

in Biochemical Journal (1996), 314 ( Pt 2)

Four GUC triplets in the coding region of the MRNA of interleukin 6 (IL-6) were examined for their suitabilty to serve as a target for hammerhead ribozome-mediated cleavage. This selection procedure was ... [more ▼]

Four GUC triplets in the coding region of the MRNA of interleukin 6 (IL-6) were examined for their suitabilty to serve as a target for hammerhead ribozome-mediated cleavage. This selection procedure was performed with the intention to downregulate IL-6 production as a potential treatment of those diseases in which IL-6 overexpression is involved. Hammerhead ribozymes and their respective short synthetic substrates (19-mers) were synthesized for these four GUC triplets. Notwithstanding the identical catalytic core sequences, the difference in base composition of the helices involved in substrate binding caused substantial variation in cleavage activity. The cleavage reactions on the 1035 nucleotide IL-6 mRNA transcript revealed that two ribozymes were able to cleave this substrate, showing a decrease in catalytic efficiency to 1/30 and 1/300 of the short substrate. This study indicates that the GUC triplet located at nucleotide 510 of the mRNA of IL-6 is the best site for hammerhead ribozyme-mediated cleavage. We suggest that in future targeting of chemically modified hammerhead ribosomes for cleavage of IL-6 RNA should be directed at this location. [less ▲]

Selection of hydrocarbon degrading bacteria with drought resistance characteristics

in Mededelingen van de Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen (Rijksuniversiteit te Gent) (1996), 61/4b

Selection of new over-producing derivatives for the improvement of extracellular lipase production by the non-conventional yeast Yarrowia lipolytica

in Journal of Biotechnology (2005), 115(4), 379-386

The non-conventional yeast Yarrowia lipolytica produces an extracellular lipase encoded by the LIP2 gene. Mutant strains with enhanced productivity were previously obtained either by chemical mutagenesis ... [more ▼]

The non-conventional yeast Yarrowia lipolytica produces an extracellular lipase encoded by the LIP2 gene. Mutant strains with enhanced productivity were previously obtained either by chemical mutagenesis or genetic engineering. In this work, we used one of these mutants, named LgX64.81 to select new overproducing strains following by amplification of the LIP2 gene. We also developed a process for lipase production in bioreactors and compared lipase production levels in batch and fed-batch cultures. Batch culture led to a lipase production of 26 450 U ml(-1) in a media containing olive oil and tryptone as carbon and nitrogen sources. Feeding of a combination of tryptone and olive oil at the end of the exponential growth phase yielded to lipase activity of 158 246 U ml(-1) after 80 h of cultivation. In addition this production system developed for the extracellular lipase could also be applied for other heterologous protein production since we have demonstrated that LgX64.81 is an interesting alternative host strain. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

Selection of resistance during sequential use of preferential antibiotic classes

in Intensive Care Medicine (2006), 32

OBJECTIVE: To determine the effect of antibiotic class pressure on the susceptibility of bacteria during sequential periods of antibiotic homogeneity. DESIGN AND SETTING: Prospective study in a mixed ICU ... [more ▼]

OBJECTIVE: To determine the effect of antibiotic class pressure on the susceptibility of bacteria during sequential periods of antibiotic homogeneity. DESIGN AND SETTING: Prospective study in a mixed ICU with three separated subunits of eight, eight, and ten beds. PATIENTS AND PARTICIPANTS: The study examined the 1,721 patients with a length of stay longer than 2 days. INTERVENTIONS: Three different antibiotic regimens were used sequentially over 2 years as first-choice empirical treatment: cephalosporins, fluoroquinolone, or a penicillin-beta-lactamase inhibitor combination. Each regimen was applied for 8 months in each subunits of the ICU, using "latin square" design. RESULTS: We treated 731 infections in 546 patients (32% of patients staying more than 48 h). There were 25.5 ICU-acquired infections per 1,000 patient-days. Infecting pathogens and colonizing bacteria were found in 2,739 samples from 1,666 patients (96.8%). No significant change in global antibiotic susceptibility was observed over time. However, a decrease in the susceptibility of several species was observed for antibiotics used as the first-line therapy in the unit. Selection pressure of antibiotics and occurrence of resistance during treatment was documented within an 8-month rotation period. CONCLUSIONS: Antibiotic use for periods of several months induces bacterial resistance in common pathogens [less ▲]

Selection of the most efficient wavelength bands for discriminating weeds from crop

in Computers & Electronics in Agriculture (2008), 62(2), 141-148

The aim of this study was to select the best combination of filters for detecting various weed species located within carrot rows. In-field images were taken under artificial lighting with a multispectral ... [more ▼]

The aim of this study was to select the best combination of filters for detecting various weed species located within carrot rows. In-field images were taken under artificial lighting with a multispectral device consisting of a black and white camera coupled with a rotating wheel holding 22 interference filters in the VIS-NIR domain. Measurements were performed over a period of 19 days, starting 1 week after crop emergence (early weeding can increase yields) and seven different weeds species were considered. The selection of the best filter combination was based on a quadratic discriminant analysis. The best combination of filters included three interference filters, respectively centred on 450, 550 and 700 nm. With this combination, the overall classification accuracy (CA) was 72%. When using only two filters, a slight degradation of the CA was noticed. When the classification results were reported on field images, a systematic misclassification of carrot cotyledons appears. Better results were obtained with a more advanced growth stage. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

La sélection porcine

Speech (2011)

Selection, efficacy, ecological characterization and formulation of fungal control agents against water hyacinth [Eichhornia crassipes (Martius) Solms] in Mali

Doctoral thesis (2011)

Rice and irrigated orchards are considered as the most important food and economical sources in Mali, which watered from Niger River. However, stable productions of rice and orchards products have been ... [more ▼]

Rice and irrigated orchards are considered as the most important food and economical sources in Mali, which watered from Niger River. However, stable productions of rice and orchards products have been limited by many disease, insects, and weeds. Recently, water hyacinth infestation in river of Niger has increased drastically and as affected by the decrease of water flow due to clogging dams and irrigation work. Biological control of weeds is an alternative approach to chemical herbicide use, focusing on the use of native fungal to control or reduce the population of water hyacinth. From 2006 to 2007, 1000 samples consisting of infected parts of water hyacinth were collected from the River Niger (District of Bamako, Segou and Niono with GPS coordinates “12° 40’ N, 7° 59’ W” ; “13° 26’ N, 6° 15’ W” and “14° 15’ N, 5° 59’ W” respectively) in Mali. Fungal belonging to seven genera (116 isolates in all) were recovered from surface-sterilized water hyacinth parts with pronounced blight symptoms. On the basis of in vivo pathogenicity tests in which the diseased leaf area percentage was estimated visually and disease severity was estimated (by calculating a disease severity index), three isolates emerged as causing severe disease: Fusarium sp. isolate Mln799 (DS = 70%), Cadophora sp. isolate Mln715 (70%), and Alternaria sp. isolate Mlb684 (71%), identified respectively as Gibberella sacchari (Anamorph. Fusarium sacchari), Cadophora malorum, and Alternaria sp. This is the first report to highlight C. malorum as a candidate biocontrol agent for water hyacinth. Influence of ecological parameter, water activity (0.880 - 0.960aw modified par glycerol) and temperature (15-35°C) on viable conidia and mycelial growth rate of Alternaria sp. (isolate Mlb684), F. sacchari (isolate Mln799) and C. malorum (isolate Mln715) were evaluated. Germination and mycelial growth dropped as aw of the medium decreased. Results showed a significant effect of aw, temperature and their interaction on mycelial growth (P < 0.0001). Growth models for F. sacchari (isolate Mln799), C. malorum (isolate Mln715) and Alternaria sp. (isolate Mlb684) differed slightly, with R2 values of 93.40, 85.89 and 77.31% respectively. Mycelial growth models, no different between predicted and experimental values was observed. Results confirm the previous finding that aw has greater influence on growth of F. sacchari (isolate Mln799), C. malorum (isolate Mln715) and Alternaria sp. (isolate Mlb684) than temperature. Analyse of 5 target regions of isolate Mlb684 genome (18 and 28S ribosomal RNA genes, Elongation factor-1 alpha gene, calmodulin gene and actin gene) allowed identifying this isolate as new specie in Alternaria genus. The strain has been deposited under accession number MUCL 53159 in the Industrial Fungal & Yeast Collection (BCCMTM/MUCL, Belgium) and DNA sequences have been deposited in GenBank. We have named it “Alternaria jacinthicola Dagno & M.H. Jijakli”. It was the first sequenced of calmodulin gene reported in Alternaria genus. Water hyacinth, paddy and wheat substrates for mass production of these biocontrol agents were evaluated. Greater sporulation of C. malorum (isolate Mln715) was observed on water hyacinth substrate (4.08 x 107 spores ml-1) following by wheat (1.06 x 107 spores ml-1). Biocontrol efficacy of fungal isolates found to be enhanced with unrefined Carapa procera (L) oil and refined palm oil supplemented with soybean lecithin in greenhouse. Applying C. malorum (isolate Mln715) and A. jacinthicola (MUCL 53159 strain) in vegetable oil emulsion [Carapa procera (L) and palm oils] caused 87.02 to 93.13% of damage severity on water hyacinth 6 weeks after treatment. Field trials showed lower efficacy control than greenhouse tests. In host specificity tests, neither C. malorum isolate Mln715 nor Alternaria sp. isolate Mlb684 showed any pathogenicity towards any member of a panel of 17 crop plants of economic importance in Mali. [less ▲]

Sélectionner les enseignants

in Perspectives : Revue Trimestrielle de l'Education (1980), 10(3), 350-356

Selective adsorption of dioxins and PCBs from marine oils on activated carbon

in Organohalogen Compounds (2003)

Selective and persistent measles virus infection of mouse neurons in vitro

in Journal of Neuropathology and Experimental Neurology (1980), 39(3), 185-185