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1

Induction of genetic variation in vitro

100%
Skucinska B.
Biotechnologia
|
2001
|
issue 3
145-151
EN
The effectiveness of traditional methods for inducing genetic variation has greatly increased with the introduction of various techniques in vitro. The new methods of obtaining generative and somatic hybrids in vitro have resulted in a greater recombinant variation, exceeding the levels delimited hitherto by mating barriers. The potential for producing mutants has expanded due to the use of mutant somatic cells (brought in with the explant) as well as to the application of mutagens to individual cells and protoplasts, the haploid ones in particular. Two specific types of variation, i.e. somaclonal and gametoclonal variation, have proved to arise under the influence of various factors in tissue culture. However, the full application of these two types is inhibited to some extent by the constrains on the regeneration ability of plants in culture, on the possibility to select variants in vitro, and on the continuity of the resulting changes. Cultures in vitro also make it possible to introduce directional genetic changes through the application of molecular techniques.
2

The selection of mosaic (MSC) phenotype after passage of cucumber (Cucumis sativus L.) through cell culture ? a method to obtain plant mitochondrial mutants

100%
Bartoszewski G., Havey M. J., Ziolkowska A., Dlugosz M., Malepszy S.
Journal of Applied Genetics
|
2007
|
vol. 48
|
issue 1
1-9
EN
Mosaic (MSC) mutants of cucumber (Cucumis sativus L.) appear after passage through cell cultures. The MSC phenotype shows paternal transmission and is associated with mitochondrial DNA rearrangements. This review describes the origins and phenotypes of independently produced MSC mutants of cucumber, including current knowledge on their mitochondrial DNA rearrangements, and similarities of MSC with other plant mitochondrial mutants. Finally we propose that passage of cucumber through cell culture can be used as a unique and efficient method to generate mitochondrial mutants of a higher plant in a highly homozygous nuclear background.
3

The selection of mosaic (MSC) phenotype after passage of cucumber (Cucumis sativus L.) through cell culture ? a method to obtain plant mitochondrial mutants

100%
Bartoszewski G., Havey M., Ziolkowska A., Dlugosz M., Malepszy S.
|
EN
Mosaic (MSC) mutants of cucumber (Cucumis sativus L.) appear after passage through cell cultures. The MSC phenotype shows paternal transmission and is associated with mitochondrial DNA rearrangements. This review describes the origins and phenotypes of independently produced MSC mutants of cucumber, including current knowledge on their mitochondrial DNA rearrangements, and similarities of MSC with other plant mitochondrial mutants. Finally we propose that passage of cucumber through cell culture can be used as a unique and efficient method to generate mitochondrial mutants of a higher plant in a highly homozygous nuclear background.
4

Alteration in bovine growth hormone histidine 22 results in transgenic mice with an enhance diabetogenic profile

100%
Parks E., Striker L. J., Striker G. E., Kopchick J. J.
Biotechnologia
|
1998
|
issue 2
161-173
EN
Transgenic mice which overexpress growth hormone (GH) may be used a model system to examine growth, kidney pathology, as well as the medical condition known as acromegaly (hyper-growth hormone secretion). GH is a pleiotropic 22 kDa polypeptide hormone which elicits body growth in jeuvenille animals and also mediates protein, carbohydrate, and lipid metabolism. The structure / function relationships of selected residues of bovine (b) GH a-helix I were approached using site-directed mutagenesis in concert with the production of bGH analog transgenic mice. Phenyalanine (Phe, F) 11 and histidine (His, H) 22 in the amino-terminus of bGH were the targeted amino acids. bGH and the bGH analog transgenic mice all exhibited the enhanced growth phenotype similar to bGH transgenic mice and had elevated IGF-1 serum concentrations. However, bGH-H22R mice demonstrated levels of blood urea nitrogen (BUN) and serum creatinine (SCR) several fold higher than the other transgenic mice. Elevated BUN and SCR are an indication of renal insufficiency in this mouse line. Glucose tolerance testing in the bGH-H22R mice revealed that they possessed a lower tolerance for glucose, or an enhancement of the diabetogenic properties of the hormone as compared to wild-type and other GH analog transgenic mice: In addition to the glomerulosclerosis found in bGH mice, histological examination of the mature bGH-H22R mice demonstrated severe glomerulosclerosis, as well as cystic kidney lesions.
5

Utility of Aureobasidium pullulans and pullulan in food biotechnology

100%
Gniewosz M., Sobczak E.
Biotechnologia
|
1999
|
issue 2
81-93
EN
Fungus Aureobasidium pullulans is the producer of numerous valuable substances (enzymes, melanins, antibiotics). Pullulan - the product of metabolism of A. pullulans strains has a great potential utility in food industry. Since chemical synthesis of pullulan is expensive, a great effort has been made to improve the productivity of A. pullulans strains. The application of mutagenesis (UV light, several chemical mutagenes) allowed to receive mutants with high productivity of that compound. The most promising mutants are those which produce pullulan with
6

The significance of plant genetic transformation for modern research

88%
Niemirowicz-Szczytt K.
Biotechnologia
|
2006
|
issue 4
164-167
EN
It has been over ten years now since genetically modified plants, obtained due to genetic transformation, started to be cultivated in many countries all over the world. As a rule, a GM plant is characterized by a new trait developed as a result of gene/genes (T-DNA), derived from another organism. It seems that no in sufficient attention has been paid to the fact that genetic transformation has provided a useful tool for functional plant genomics. The identification of genome sequences of a few species (such as Arabidopsis thaliana, Oryza sativa i Medicago truncatula) and significant progress in genome sequencing of some others, including trees (Populus trichocarpa), lead to an inevitable question about the function of genes. It is the knowledge of the function of DNA sequences that allows for their practical applications. Insertional mutagenesis, based on T-DNA incorporation, meant to cause gene modification resulting in the development of new plant phenotypes. Mutant phenotype ensures isolation and identification of the modified gene. In order to identify the function of a gene which does not bring about phenotype changes, it is necessary to supplement an inserted DNA segment with sequences enabling the monitoring of gene expression. Gene silencing technology is another way to get the information about gene function and to control genes. New techniques are being enriched with improved chemical and physical mutation methods. Further studies and new applications are greatly facilitated by the detection of gene functions with the use of insertional mutagenesis, gene silencing strategy and evaluation of gene expression.
7

Induction and characterization of streptomycin-resistant mutants in Capsicum praetermissum

75%
Venkataiah P., Christopher T., Subhash K.
Journal of Applied Genetics
|
2005
|
vol. 46
|
issue 1
19-24
EN
Streptomycin-resistant mutants were isolated from mutagenised cotyledon explants of Capsicum praetermissum Heiser & Smith. The explants were mutagenised with N-ethyl-N-nitrosourea, which resulted in a high frequency of streptomycin-resistant mutants (18.0%) and a low frequency of chlorophyll-deficient (albino) mutants (8.0%). Complete streptomycin-resistant plantlets were obtained after rooting of the regenerated green shoots on rooting medium containing 1.0 mg L?1 IAA and 500 mg L?1 streptomycin sulphate. Leaf-segment assay of these plantlets revealed that they were resistant to streptomycin but sensitive to chloramphenicol, kanamycin, lincomycin, and spectinomycin. Reciprocal crosses between streptomycin-resistant and -sensitive plants showed a non-Mendelian transmission of resistance by female parents.
8

Microspore culture of winter oilseed rape (Brassica napus L.) in conjunction with other in vitro technologies

75%
Cegielska-Taras T., Szala L., Bartkowiak-Broda I.
|
EN
Microspore culture in conjuction with other technologies such as selection, mutagenesis and transformation has been used for the production of novel genotypes of Brassica napus L. for crop improvement. The example of in vitro selection of microspore - derived embryos includes: a) ploidy level, b) seed oil composition (for example: high level of erucic acid), c) genotypes with restorer gene for CMS-ogura system (by means of isozyme marker PGI-2 ), d) herbicide resistant forms. Efficiency of microspore mutagnesis has been tested by the treatment of freshly isolated microspores with UV and MNU. Direct delivery of foreign gene to the microspores (microprojectile bombardment) combined with the use of Agrobacterium tumefaciens to microspore derived embryos seems to be a promising way of oilseed rape transformation.
9

3D domain swapping ? implications for conformational disorders and ways of control

63%
Jaskolski M.
Biotechnologia
|
2011
|
issue 1
34-44
EN
3D Domain swapping is a mechanism of protein aggregation, in which a structural element of a protein fold is replaced by an identical element from another subunit. Some proteins, for instance RNase A, can assume many domain- swapped forms, thus undermining the dogma,'one sequence ? one structure' in a particularly spectacular way. Completed in a mutual fashion, it is a mechanism of protein oligomerization. In an open-ended fashion, 3D domain swapping could be a mechanism of amyloid fibril formation. In another mechanism, possibly operating together with domain swapping, a specific sequence, such as a glutamine expansion, could form a ?-spine of the fibril in a motif called steric zipper. The first connection between 3D domain swapping and amyloidogenicity was established in human cystatin C (HCC), the second - in the prion protein (PrP). In both cases, a disulfide bridge (natural in PrP, engineered in HCC) can be used for redox control of 3D domain swapping and to demonstrate that it is indeed involved in amyloid fibril formation. HCC has a naturally occurring L68Q mutant with drastically increased propensity for aggregation. The L68Q mutation occurs at the closed interface, or protein core. Mutations in other areas, such as the flexible hinge (especially deletions and insertions) can also be used to control 3D domain swapping and aggregation. Paradoxically, 3D domain swapping can also be used by Nature for prevention of nucleation processes that lead to high-order aggregates or crystals. Such a situation exists in the eye lens, where despite astronomical concentration of crystallins, the solution remains clear. One of the Nature's tricks to achieve polydispersity is to use a palindromic sequence for the swapped domain, thereby frustrating the growth of aggregates by constantly changing the interaction topology.
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