scholarly journals A New Medicago truncatula Line with Superior in Vitro Regeneration, Transformation, and Symbiotic Properties Isolated Through Cell Culture Selection

1997 ◽  
Vol 10 (3) ◽  
pp. 307-315 ◽  
Author(s):  
Beate Hoffmann ◽  
Toan Hanh Trinh ◽  
Jeffrey Leung ◽  
Adam Kondorosi ◽  
Eva Kondorosi
Keyword(s):  
Medicago Truncatula ◽  
In Vitro Selection ◽  
Rhizobium Meliloti ◽  
In Vitro Regeneration ◽  
Selection Procedure ◽  
Genetic System ◽  
Strain Specificity ◽  
Meliloti Strain ◽  
Symbiotic Properties

The understanding of how leguminous plants establish symbiosis with rhizobia is limited by the lack of genetic system in most legume plants. Here we propose a Medicago truncatula line suitable for genetic analysis of Medicago-Rhizobium meliloti symbiosis because of its high regeneration capacity and broad R. meliloti strain specificity. This line has been isolated by extensive in vitro screening of explants from several ecotypes of M. truncatula that are known to be autogamous and have small diploid genomes. One such derivative identified from ecotype 108-1 has gained the capacity to be readily regenerated in vitro. The derivative, called R108-1, like its parent, can establish effective symbiosis with several widely studied R. meliloti strains (Rm41, Rm2011, Rm1021, F51, and GR4). Importantly, the nodulation characteristics of the R108-1 line were not compromised by the in vitro selection procedure. We have further established the conditions for efficient transformation of R108-1 by co-cultivation with Agrobacterium tumefaciens. Thus, this in vitro-derived plant line has most of the favorable attributes, otherwise rare among legumes, of a complementary model plant system for investigating symbiosis at the genetic and the molecular levels.

scholarly journals Identification of Resistance Determinants for a Promising Antileishmanial Oxaborole Series

2021 ◽  
Vol 9 (7) ◽  
pp. 1408
Author(s):  
Magali Van den Kerkhof ◽  
Philippe Leprohon ◽  
Dorien Mabille ◽  
Sarah Hendrickx ◽  
Lindsay B. Tulloch ◽  
...  
Keyword(s):  
Drug Exposure ◽  
In Vitro Selection ◽  
Selection Procedure ◽  
Cosmid Library ◽  
Neglected Diseases ◽  
Chromosome 2 ◽  
Resistance Determinants ◽  
A Genome

Current treatment options for visceral leishmaniasis have several drawbacks, and clinicians are confronted with an increasing number of treatment failures. To overcome this, the Drugs for Neglected Diseases initiative (DNDi) has invested in the development of novel antileishmanial leads, including a very promising class of oxaboroles. The mode of action/resistance of this series to Leishmania is still unknown and may be important for its further development and implementation. Repeated in vivo drug exposure and an in vitro selection procedure on both extracellular promastigote and intracellular amastigote stages were both unable to select for resistance. The use of specific inhibitors for ABC-transporters could not demonstrate the putative involvement of efflux pumps. Selection experiments and inhibitor studies, therefore, suggest that resistance to oxaboroles may not emerge readily in the field. The selection of a genome-wide cosmid library coupled to next-generation sequencing (Cos-seq) was used to identify resistance determinants and putative targets. This resulted in the identification of a highly enriched cosmid, harboring genes of chromosome 2 that confer a subtly increased resistance to the oxaboroles tested. Moderately enriched cosmids encompassing a region of chromosome 34 contained the cleavage and polyadenylation specificity factor (cpsf) gene, encoding the molecular target of several related benzoxaboroles in other organisms.

scholarly journals High efficacy in vitro selection procedure for generating transgenic parasites of Plasmodium berghei using an antibiotic toxic to rodent hosts

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Akira Soga ◽  
Hironori Bando ◽  
Mami Ko-ketsu ◽  
Hirono Masuda-Suganuma ◽  
Shin-ichiro Kawazu ◽  
...  
Keyword(s):  
Plasmodium Berghei ◽  
In Vitro Selection ◽  
Selection Procedure ◽  
High Efficacy ◽  
Transgenic Parasites

Osmotic shock improves Tnt1 transposition frequency in Medicago truncatula cv Jemalong during in vitro regeneration

2009 ◽  
Vol 28 (10) ◽  
pp. 1563-1572 ◽  
Author(s):  
Anelia Iantcheva ◽  
Mireille Chabaud ◽  
Viviane Cosson ◽  
Marielle Barascud ◽  
Bernadette Schutz ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Osmotic Shock ◽  
In Vitro Regeneration ◽  
Transposition Frequency

Aptamer-based modulation of blood coagulation

2011 ◽  
Vol 31 (04) ◽  
pp. 258-263 ◽  
Author(s):  
F. Rohrbach ◽  
B. Pötzsch ◽  
J. Müller ◽  
G. Mayer
Keyword(s):  
Clinical Trials ◽  
Nucleic Acid ◽  
In Vitro Selection ◽  
Three Dimensional ◽  
Selection Procedure ◽  
Anticoagulant Drugs ◽  
Coagulation Proteins ◽  
Recent Developments ◽  
Target Molecules

SummaryNucleic acid based aptamers are singlestranded oligonucleotide ligands isolated from random libraries by an in-vitro selection procedure. Through the formation of unique three-dimensional structures, aptamers are able to selectively interact with a variety of target molecules and are therefore also promising candidates for the development of anticoagulant drugs. While thrombin represents the most prominent enzymatic target in this field, also aptamers directed against other coagulation proteins and proteases have been identified with some currently being tested in clinical trials.In this review, we summarize recent developments in the design and evaluation of aptamers for anticoagulant therapy and research.

scholarly journals DNAmoreDB, a database of DNAzymes

2020 ◽  
Vol 49 (D1) ◽  
pp. D76-D81
Author(s):  
Almudena Ponce-Salvatierra ◽  
Pietro Boccaletto ◽  
Janusz M Bujnicki
Keyword(s):  
In Vitro Selection ◽  
Structural Information ◽  
Selection Procedure ◽  
Living Organisms ◽  
Catalyzed Reactions ◽  
Submission Form ◽  
Types Of Information ◽  
Machine Readable ◽  
Readable Format

Abstract Deoxyribozymes, DNA enzymes or simply DNAzymes are single-stranded oligo-deoxyribonucleotide molecules that, like proteins and ribozymes, possess the ability to perform catalysis. Although DNAzymes have not yet been found in living organisms, they have been isolated in the laboratory through in vitro selection. The selected DNAzyme sequences have the ability to catalyze a broad range of chemical reactions, utilizing DNA, RNA, peptides or small organic compounds as substrates. DNAmoreDB is a comprehensive database resource for DNAzymes that collects and organizes the following types of information: sequences, conditions of the selection procedure, catalyzed reactions, kinetic parameters, substrates, cofactors, structural information whenever available, and literature references. Currently, DNAmoreDB contains information about DNAzymes that catalyze 20 different reactions. We included a submission form for new data, a REST-based API system that allows users to retrieve the database contents in a machine-readable format, and keyword and BLASTN search features. The database is publicly available at https://www.genesilico.pl/DNAmoreDB/.

scholarly journals Current Perspectives on Aptamers as Diagnostic Tools and Therapeutic Agents

Pharmaceutics ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 646 ◽  
Author(s):  
Prabir Kumar Kulabhusan ◽  
Babar Hussain ◽  
Meral Yüce
Keyword(s):  
In Vitro Selection ◽  
Clinical Investigation ◽  
Environmental Pollutants ◽  
Selection Procedure ◽  
Iteration Process ◽  
High Specificity ◽  
Molecular Probes ◽  
Diagnostic Tools ◽  
Vast Number

Aptamers are synthetic single-stranded DNA or RNA sequences selected from combinatorial oligonucleotide libraries through the well-known in vitro selection and iteration process, SELEX. The last three decades have witnessed a sudden boom in aptamer research, owing to their unique characteristics, like high specificity and binding affinity, low immunogenicity and toxicity, and ease in synthesis with negligible batch-to-batch variation. Aptamers can specifically bind to the targets ranging from small molecules to complex structures, making them suitable for a myriad of diagnostic and therapeutic applications. In analytical scenarios, aptamers are used as molecular probes instead of antibodies. They have the potential in the detection of biomarkers, microorganisms, viral agents, environmental pollutants, or pathogens. For therapeutic purposes, aptamers can be further engineered with chemical stabilization and modification techniques, thus expanding their serum half-life and shelf life. A vast number of antagonistic aptamers or aptamer-based conjugates have been discovered so far through the in vitro selection procedure. However, the aptamers face several challenges for its successful clinical translation, and only particular aptamers have reached the marketplace so far. Aptamer research is still in a growing stage, and a deeper understanding of nucleic acid chemistry, target interaction, tissue distribution, and pharmacokinetics is required. In this review, we discussed aptamers in the current diagnostics and theranostics applications, while addressing the challenges associated with them. The report also sheds light on the implementation of aptamer conjugates for diagnostic purposes and, finally, the therapeutic aptamers under clinical investigation, challenges therein, and their future directions.

scholarly journals The effects of β-lactam antibiotics and hygromycin B on de novo shoot organogenesis in apple cv. Golden Delicious

2018 ◽  
Vol 70 (1) ◽  
pp. 179-190 ◽  
Author(s):  
Mariana Stanisic ◽  
Slavica Ninkovic ◽  
Jelena Savic ◽  
Tatjana Cosic ◽  
Nevena Mitic
Keyword(s):  
Shoot Regeneration ◽  
De Novo ◽  
Shoot Organogenesis ◽  
In Vitro Regeneration ◽  
Leaf Explants ◽  
Selection Procedure ◽  
Transformation Process ◽  
Hygromycin B ◽  
Golden Delicious

Since the genetic transformation of the apple is strongly genotype-dependent and generally inefficient, the evaluation of factors affecting shoot regeneration are crucial for the establishment of a successful transformation process. In this report, we evaluated the effects of the ?-lactam antibiotics meropenem and timentin on in vitro regeneration via de novo shoot organogenesis from leaf explants of apple cv. Golden Delicious, as well as on the growth of the Agrobacterium tumefaciens strain EHA 105, and compared them with the commonly used ?-lactam cefotaxime. Also, we report for the first time the effect of hygromycin B as a selective agent in the domesticated apple, as regards shoot regeneration and shoot multiplication efficiency. We observed that cefotaxime and timentin at concentrations higher than 100 mg L-1 were sufficient to prevent Agrobacterium growth during a two-week period, while meropenem exhibited an inhibitory effect on bacterial growth at all tested concentrations (25-150 mg L-1). Cefotaxime at a concentration of 300 mg L-1 increased the number of regenerated shoots per explant (9.39) in comparison with the control (7.67). In contrast to cefotaxime, meropenem and timentin caused a decrease in shoot regeneration efficiency, but larger and more developed shoots were obtained on meropenem (25-125 mg L-1) after the same period of cultivation. Hygromycin B at a concentration of 5 mg L-1 or higher completely inhibited shoot regeneration and induced explant tissue necrosis. Therefore, the selection procedure with a final concentration of 4 mg L-1 throughout organogenesis and 10 mg L-1 for further shoot growth and multiplication is recommended for an efficient transformation process in apple cv. Golden Delicious.

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