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Genetically modified animals as models of pulmonary disease.

Improvements in biological research and the development of new techniques for human health protection require animal experimentation of various species. In particular, animal models are always necessary to test new therapies for the treatment of various human diseases. The latest advances in molecular biology involving genetic modification are aimed at developing new animal models of human diseases that are not present in spontaneous murine broods or obtainable with other experimental manipulations. Transgenic techniques and, in particular, the possibility to directly modify specific genetic information in the experimental animal have led to the acquisition of important knowledge on the physiologic functions of many proteins and their function in the course of various diseases. The advent of new transgenic animals is opening up new and interesting frontiers, full of hope and opportunity, for the research into pulmonary diseases. New advances in cystic fibrosis, emphysema, and pulmonary fibrosis have been made through the study of a large number of proteins implicated in the complex of acute and chronic inflammatory processes of lung parenchyma, which are responsible for permanent changes in organ structure and function. Recent studies carried out on murine inbred strains have yielded significant new data on the multifactor origin of pulmonary disease, because of their correlation with the major histocompatibility complex (H2 in mice) or through the different genetic map of the strains. Today it is possible to outweigh or potentiate the function and expression of some genes, obtaining a deficit or abundance, respectively, of specific proteins. These techniques have permitted and will continue to permit the development of new models of human disease, leading to further therapeutic advances as a consequence.

Animals↗

Transgene introgression from genetically modified crops to their wild relatives.

Transgenes engineered into annual crops could be unintentionally introduced into the genomes of their free-living wild relatives. The fear is that these transgenes might persist in the environment and have negative ecological consequences. Are some crops or transgenic traits of more concern than others? Are there natural genetic barriers to minimize gene escape? Can the genetic transformation process be exploited to produce new barriers to gene flow? Questions abound, but luckily so do answers.

Crops, Agricultural↗

Transgene elimination in genetically modified dry bean and soybean lines.

Transgene elimination is a poorly studied phenomenon in plants. We made genetic and molecular studies of a transgenic dry bean line immune to bean golden mosaic geminivirus and a soybean line. In both lines, the transgenes were stable during the vegetative phase but were eliminated during meiosis. Due to its potential biotechnological value, this transgenic line was micropropagated by grafting and the vegetative copies were studied for more than two years. More than 300 plants of progeny were obtained during this period, demonstrating that the phenomenon of elimination was consistently repeated and offering an opportunity for detailed study of transgene elimination, including the characterization of the integration sites. Cloning and sequencing of the transgenic loci, reciprocal crosses to untransformed plants, genomic DNA blots, and GUS assays were performed in the transgenic lines. Based on the molecular and genetic characterization, possible mechanisms involved in transgene elimination include intrachromosomal recombination, genetic instability resulting from the tissue culture manipulations, and co-elimination of transgenes, triggered by a process of genome defense.

DNA, Plant↗

Increased digestibility of two products in genetically modified food (CP4-EPSPS and Cry1Ab) after preheating.

We performed experiments on in vitro digestion of newly expressed proteins by SGF (simulated gastric fluid) and SIF (simulated intestinal fluid) to assess the allergenicity of food components derived from biotechnological modification. For newly expressed proteins, we chose CP4-EPSPS (5-enolpyruvylshikimate-3-phosphate synthase from Agrobacterium sp. strain CP4) and Cry1Ab derived from Bacillus thuringiensis subsp. kurstaki strain HD-1. The former is expressed in GM-soybeans and the latter is expressed in GM-corns. Firstly, we examined the digestibility of purified CP4-EPSPS and Cry1Ab by SGF. Both proteins were rapidly digested within 60 sec. After preheating, the digestibility by SGF was slightly increased. Secondly, CP4-EPSPS in GM-soybean extracts and Cry1Ab in GM-corn extracts were digested by SGF. The digestion time of both proteins by SGF was almost the same as that of the purified proteins. Thirdly, the digestibility of CP4-EPSPS and Cry1Ab by SIF was examined. The digestion time of these proteins was 240 min or more. However, digestibility of these proteins by SIF was dramatically increased by preheating, and the digestion time was less than 5 sec. Fourthly, CP4-EPSPS in GM-soybean extracts and Cry1Ab in GM-corn extracts were digested by SIF. Digestion time of both proteins by SIF was almost the same as that of the purified proteins. From these results, we concluded that the digestibility of both CP4-EPSPS and Cry1Ab by SGF and SIF was increased by preheating. Therefore, we suggest that the allergenicity of both proteins should be extremely low because of the easy digestibility of these proteins by SGF and also by SIF with preheating.

Allergens↗

Scoring in genetically modified organism proficiency tests based on log-transformed results.

The study considers data from 2 UK-based proficiency schemes and includes data from a total of 29 rounds and 43 test materials over a period of 3 years. The results from the 2 schemes are similar and reinforce each other. The amplification process used in quantitative polymerase chain reaction determinations predicts a mixture of normal, binomial, and lognormal distributions dominated by the latter 2. As predicted, the study results consistently follow a positively skewed distribution. Log-transformation prior to calculating z-scores is effective in establishing near-symmetric distributions that are sufficiently close to normal to justify interpretation on the basis of the normal distribution.

Data Interpretation, Statistical↗