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1

Iron - element of life and death

100%
Strozycki P. M.
Biotechnologia
|
1999
|
issue 3
45-61
EN
Iron is the fourth most abundant element and second, after aluminium, metal in the Earth's crust. It is an essential nutrient for almost all living organisms. Iron is a component of hundreds proteins, enzymes and their cofactors. It is a central part of numerous systems, such as: oxygen transport and storage (hemoglobin), elektron transfer (cytochromes), DNA synthesis (ribonucleotide reduction), symbiotic nitrogen fixation (leghemoglobin, nitrogenase), hormone synthesis (i.e. lipoxygenases)... Due to its chemical properties, iron also poses a threat to living cells. It may catalyse one-electron transfer reactions, which (in the presence of active oxygen) generate radical species. Free radicals are the most potent oxidising agents known thus far. The best known effects of their actions include: oxidative DNA damage and lipid peroxidation. These reactions destroy the cell integrity and may lead to its death. Many of the 20th century diseases, like some cancers or heart problems, are in part caused by free radicals. In order to supply with iron and to protect from iron their components, living organisms have developed specific systems for iron acquisition and maintenance in the cell. Despite the potential risks of iron overload, 15% of the world's population suffers iron-deficiency anemia.
2

Molecular phylogenetics of representative Paramecium species

88%
Maciejewska A.
Folia Biologica
|
2007
|
vol. 55
|
issue 1-2
1-8
EN
The genus Paramecium has been known to science for 250 years and contains some of the most widely studied species of ciliates. At present, the basic research object for phylogenetic studies is the genome of various paramecia. One of the most widely used markers are genes coding for various rRNA's. Comparative analyses of sequences coding rRNA were applied for resolving the systematic position of some paramecia species and also for the establishment of an accurate taxonomy of Paramecium. Paramecia were also model organisms for their systematic group in more general studies in a comparative analysis among ciliates, fungi, plants and multicellular animals, illustrating the evolutionary relationships between Archaebacteria and Eucaryota. A new, revolutionary genealogy proposed the shifting of presumptively advanced groups towards more primitive ones, and traditionally primitive forms were located closer to highly specialized taxa, but rRNA analysis did not unambiguously resolve associations within the studied groups. Because of the aforementioned concerns, the number of molecular markers used for alternative studies is growing, such as genes coding proteins from the Hsp family or histone proteins. Other promising candidate markers may be hemoglobin genes or genes coding ?-tubulins. In case of comparative analyses of nucleotide sequences, the outcome of the research usually depends upon a subjective choice of DNA. One of the directions of research in molecular phylogenetics include indirect methods that allow for an estimation of entire genomes, for example RAPD-PCR-fingerprinting.
3

Production of the human hemoglobin from animals modified by genetic engineering

88%
Grzybowski G.
|
|
issue 1
83-94
EN
Medical and economic arguments for the investigation of methods of producing blood substitutes are presented. The paper presents the current state of investigations aimed at the production of human hemoglobin from animals modified by genetic engineering methods. Certain problems related to medicine and public perception are presented in connection with the use of 'transgenic' hemoglobin as blood substitute. Swine is at present the only species among farm animals which is used in research on the production of human hemoglobin. Animals were obtained in which 'transgenic' hemoglobin accounted for 54% of the total hemoglobin in the organism. When human hemoglobin accounted for 24% of the total, and 30% was hybrid (human/swine), the animals were in perfect health, fit for reproduction and their progeny demonstrated the same transgene expression. It is assumed that human hemoglobin, extracted from the blood of transgenic swine, will be the first commercial product used in medicine and obtained through transgenesis of domestic animals.
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