Search results for " Organism"

Instability of Tandem Repetitive DNA in “Natural” and Transgenic Organisms

1996

Genome research of the last 10 years has forced us to re-evaluate our view of DNA as a relatively stable molecule. Unprecedented levels of DNA instability in germline and soma cells have been observed, associated primarily with tandem repetitive (tr) DNA sequences. We will discuss here briefly the structure and possible functions of trDNA in eukaryotes, the putative mechanisms of mutational change in repeat clusters and the evolutionary dimensions of trDNA instability (for other relevant reviews, sec Pardue and Hennig 1990; Vogt 1990; Charlesworth et al. 1994). A special focus will be on the behaviour of trDNA after DNA transfer experiments in transgenic organisms, with reference to our own…

Assessment of Genetically Modified Organisms (GMO) in Meat Products by PCR

2010

Adventitious bud formation on isolated leaves and its significance for mutation breeding

1968

Since a mutation is a unicellular event, irradiation of a multicellular meristem results in the so-called diplontic selection. This competition between the mutated cell and the surrounding non-mutated cells is often lost by the mutated cell, causing a low frequency of mutated plants and a narrow mutation spectrum. When a mutated cell survives, chimeras are automatically formed because most apices consist of a number of fairly independent groups of cell layers. Such an undesirable situation can be improved by growing complete plants from only one cell, resulting in a high frequency of solid, non-chimeral mutants and a wide mutation spectrum. Many plant species can be stimulated to form adven…

A simple DNA extraction method suitable for PCR detection of genetically modified maize.

2010

BACKGROUND: The polymerase chain reaction (PCR) is a powerful tool that is being increasingly used for detection of transgenic DNA. PCR requires only a minute quantity of template, but sensitive and accurate testing requires DNA of sufficient purity and free from inhibitors such as plant polysaccharides. Several standard protocols are available for this purpose, but they usually involve several steps, imply destruction of the maize kernel, or are time-consuming. Our aim was to develop a fast and simple extraction method to isolate a raw DNA-containing solution from maize tissues suitable for use as a template in a PCR-based detection assay with specific oligonucleotides directed to the iden…

Progeria: Model Organisms

2019

The use of whole-mountin situhybridization to illustrate gene expression regulation

2014

In situ hybridization is a widely used technique for studying gene expression. Here, we describe two experiments addressed to postgraduate genetics students in which the effect of transcription factors on gene expression is analyzed in Drosophila embryos of different genotypes by whole-mount in situ hybridization. In one of the experiments, students analyzed the repressive effect of Snail over rhomboid expression using reporter lines containing different constructs of the rhomboid neuroectodermal enhancer fused to the lacZ gene. In the second experiment, the epistatic relationship between the cabut and decapentaplegic genes was analyzed. These simple experiments allowed students to (1) unde…

Bauplan of Urmetazoa: Basis for Genetic Complexity of Metazoa

2004

Sponges were first grouped to the animal-plants or plant-animals then to the Zoophyta or Mesozoa and finally to the Parazoa. Only after the application of molecular biological techniques was it possible to place the Porifera monophyletically with the other metazoan phyla, justifying a unification of all multicellular animals to only one kingdom, the Metazoa. The first strong support came from the discovery that cell-cell and cell-matrix adhesion molecules that were cloned from sponges and were subsequently expressed share a high DNA sequence and protein function similarity with the corresponding molecules of other metazoans. Besides these evolutionary novelties for Metazoa, sponges also hav…

A novel approach for the improvement of stress resistance in wine yeasts

2006

During wine production yeast cells are affected by several stress conditions that could affect their viability and fermentation efficiency. In this work we describe a novel genetic manipulation strategy designed to improve stress resistance in wine yeasts. This strategy involves modifying the expression of the transcription factor MSN2, which plays an important role in yeast stress responses. The promoter in one of the genomic copies of this gene has been replaced by the promoter of the SPI1 gene, encoding for a cell wall protein of unknown function. SPI1 is expressed at late phases of growth and is regulated by Msn2p. This modification allows self-induction of MSN2 expression. MSN2 gene tr…

Evaluation of different genetic procedures for the generation of artificial hybrids in Saccharomyces genus for winemaking

2012

Several methods based on recombinant DNA techniques have been proposed for yeast strain improvement; however, the most relevant oenological traits depend on a multitude of loci, making these techniques difficult to apply. In this way, hybridization techniques involving two complete genomes became interesting. Natural hybrid strains between different Saccharomyces species have been detected in diverse fermented beverages including wine, cider and beer. These hybrids seem to be better adapted to fluctuating situations typically observed in fermentations due to the acquisition of particular physiological properties of both parental strains. In this work we evaluated the usefulness of three dif…

Contaminants of emerging concern in freshwater fish from four Spanish Rivers.

2019

This study investigated the occurrence of 135 contaminants of emerging concern (CECs) – pharmaceuticals, pesticides, a set of endocrine disrupting compounds (EDCs) (parabens, bisphenols, hormones, triazoles, organophosphorus flame retardants and triclosan), UV-filters, perfluoroalkyl substances (PFASs) and halogenated flame retardants (HFRs) – in 59 fish samples, collected in 2010 in 4 Spanish Rivers (Guadalquivir, Júcar, Ebro and Llobregat). Of the 135 CECs, 76 including 8 pharmaceuticals, 25 pesticides, 10 EDCs, 5 UV-filters, 15 PFASs and 13 HFRs were detected. Pharmaceuticals were the less frequently found and at lower concentrations. Pesticides, EDCs, UV-filters, PFASs and HFRs were det…