In Vitro Selection of Imazethapyr-Tolerant Tomato (Lycopersicon esculentumMill.)

Effectiveness of cyclical in vitro selection for imazethapyr tolerance in tomato was studied. Cotyledons and leaf explants from shoots regenerated on media containing imazethapyr were used to initiate three successive cycles of selection. Increases in tissue viability, callus initiation, and callus proliferation were observed following three cycles of selection on 10−7M imazethapyr. Dry matter accumulation of unselected tomato seedlings was reduced by 50% when imazethapyr was applied postemergence at a rate of 28 g ae ha−1. Progeny of eight tomato lines selected after one cycle of selection had greater tolerance to imazethapyr than control plants (60 to 70% dry matter accumulation versus 50%, respectively). Variability was also generated for imazethapyr tolerance among progeny of the same tomato line.

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Riboswitch identification using Ligase-Assisted Selection for the Enrichment of Responsive Ribozymes (LigASERR)

Synthetic Biology ◽

10.1093/synbio/ysz019 ◽

2019 ◽

Vol 4 (1) ◽

Cited By ~ 1

Author(s):

Matthew C Haines ◽

Marko Storch ◽

Diego A Oyarzún ◽

Guy-Bart Stan ◽

Geoff S Baldwin

Keyword(s):

In Vitro Selection ◽

Selection Process ◽

Alternative Methods ◽

Target Sequence ◽

Selection Methods ◽

Generating Functional ◽

Selection For ◽

Selection Of

Abstract In vitro selection of ligand-responsive ribozymes can identify rare, functional sequences from large libraries. While powerful, key caveats of this approach include lengthy and demanding experimental workflows; unpredictable experimental outcomes and unknown functionality of enriched sequences in vivo. To address the first of these limitations, we developed Ligase-Assisted Selection for the Enrichment of Responsive Ribozymes (LigASERR). LigASERR is scalable, amenable to automation and requires less time to implement compared to alternative methods. To improve the predictability of experiments, we modeled the underlying selection process, predicting experimental outcomes based on sequence and population parameters. We applied this new methodology and model to the enrichment of a known, in vitro-selected sequence from a bespoke library. Prior to implementing selection, conditions were optimized and target sequence dynamics accurately predicted for the majority of the experiment. In addition to enriching the target sequence, we identified two new, theophylline-activated ribozymes. Notably, all three sequences yielded riboswitches functional in Escherichia coli, suggesting LigASERR and similar in vitro selection methods can be utilized for generating functional riboswitches in this organism.

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Selection of valine-resistance in callus culture of Arabidopsis thaliana (L.) Heynh. derived from leaf explants

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1999.028 ◽

2014 ◽

Vol 68 (3) ◽

pp. 211-215

Author(s):

Małgorzata D. Gaj ◽

Grzegorz Czaja ◽

Małgorzata Nawrot

Keyword(s):

Arabidopsis Thaliana ◽

In Vitro Selection ◽

Callus Formation ◽

Leaf Explants ◽

Average Frequency ◽

Leaf Explant ◽

Regeneration Ability ◽

Valine Resistance ◽

Selection Of

The selection of valine-resistant mutants was carried out in leaf explant cultures of three <em>Arabidopsis thaliana</em> (L.) Heynh. ecotypes: C-24, RLD and Columbia. The valine concentration used for in vitro selection, lethal for seed-growing plants, has not affected callus formation and growth. However, strong inhibition of shoot regeneration ability of calli growing under selection pressure was noticed. In total, 1043 explants were cultured on valine medium and 18 shoots were regenerated with an average frequency of 1.7 shoots per 100 calli. Most R<sub>1</sub> shoots were sterile and seeds were collected from 3 plants. The transmission of valine-resistance to the sexual progeny of these plants was scored and the increased level of valine-resistance was found in progeny of one line - 61 C. This line originated from the culture of Columbia leaf explant and displayed tetraploid chromosome number.

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Faculty Opinions recommendation of In vitro selection of a deoxyribozyme that can utilize multiple substrates.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1004319.49956 ◽

2002 ◽

Author(s):

Niles Lehman

Keyword(s):

In Vitro Selection ◽

Multiple Substrates ◽

Selection Of

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Faculty Opinions recommendation of CIS display: In vitro selection of peptides from libraries of protein-DNA complexes.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1017658.206556 ◽

2004 ◽

Author(s):

Sachdev Sidhu

Keyword(s):

In Vitro Selection ◽

Dna Complexes ◽

Selection Of

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The Effects of Shock Vancomycin Concentrations on the Formation of Heteroresistance in Staphylococcus aureus

Antibiotics and Chemotherapy ◽

10.37489/0235-2990-2020-65-9-10-3-7 ◽

2020 ◽

Vol 65 (9-10) ◽

pp. 3-7

Author(s):

V. V. Gostev ◽

Yu. V. Sopova ◽

O. S. Kalinogorskaya ◽

M. E. Velizhanina ◽

I. V. Lazareva ◽

...

Keyword(s):

Staphylococcus Aureus ◽

In Vitro Selection ◽

Methicillin Resistant Staphylococcus Aureus ◽

High Concentration ◽

Short Term ◽

High Concentrations ◽

Selection Of ◽

Selection Of Resistance ◽

Test Cultures

Glycopeptides are the basis of the treatment of infections caused by MRSA (Methicillin-Resistant Staphylococcus aureus). Previously, it was demonstrated that antibiotic tolerant phenotypes are formed during selection of resistance under the influence of high concentrations of antibiotics. The present study uses a similar in vitro selection model with vancomycin. Clinical isolates of MRSA belonging to genetic lines ST8 and ST239, as well as the MSSA (ATCC29213) strain, were included in the experiment. Test isolates were incubated for five hours in a medium with a high concentration of vancomycin (50 μg/ml). Test cultures were grown on the medium without antibiotic for 18 hours after each exposure. A total of ten exposure cycles were performed. Vancomycin was characterized by bacteriostatic action; the proportion of surviving cells after exposure was 70–100%. After selection, there was a slight increase in the MIC to vancomycin (MIC 2 μg/ml), teicoplanin (MIC 1.5–3 μg/ml) and daptomycin (MIC 0.25–2 μg/ml). According to the results of PAP analysis, all strains showed an increase in the area under curve depending on the concentration of vancomycin after selection, while a heteroresistant phenotype (with PAP/AUC 0.9) was detected in three isolates. All isolates showed walK mutations (T188S, D235N, E261V, V380I, and G223D). Exposure to short-term shock concentrations of vancomycin promotes the formation of heteroresistance in both MRSA and MSSA. Formation of VISA phenotypes is possible during therapy with vancomycin.

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