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- Dzhambazov, Balik, et al.
(författare)
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Morphological, genetic and functional variability of a T-cell hybridoma line.
- 2003
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Ingår i: Folia Biologica. - 0015-5500. ; 49:2, s. 87-94
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Tidskriftsartikel (refereegranskat)abstract
- The variability in the morphology, modal number of chromosomes, TCR expression and functional reactivity of a CII-specific T-cell hybridoma at continuous subcultivation have been investigated. As the number of passages increased, besides the oval semiadherent cells (normal phenotype), fibroblast-like cells (transformed phenotype) were also observed. The two cell subpopulations differed in their karyotype characteristic, as well as in their functional reactivity. The cell population with a normal phenotype was characterized by a tetramodal number of chromosomes (30, 40, 48 and 70) and trisomies of chromosomes 6 and 14, while the cell population with a transformed phenotype was characterized by a trimodal number of chromosomes (11, 68 and 74) and trisomy of chromosome 12. A nullisomy of sex chromosomes was established in both types of cells. In the initial passages of subcultivation, 73.04% of the cells with a normal morphological phenotype expressed TCR-CD3 complexes on their surface and possessed high functional reactivity. After a two-week subcultivation, the values of these indices went down considerably: 46.11% of the cells expressed functional TCR-CD3 complexes, as a result of which their functional reactivity decreased. Only 2.71% of the cells with a transformed morphological phenotype expressed functional TCR-CD3 complexes on their surface. In these cells, a total loss of reactivity towards the specific antigens was established. The achieved results show that at continuous subcultivation the T-cell hybridomas are unstable, and with the increase in the number of passages there appear chromosome rearrangements, leading to loss of their functional reactivity.
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| 5. |
- Liska, F, et al.
(författare)
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Chromosome assignment of Cd36 transgenes in two rat SHR lines by FISH and linkage mapping of transgenic insert in the SHR-TG19 line.
- 2002
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Ingår i: Folia biologica. - 0015-5500. ; 48:4, s. 139-44
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Tidskriftsartikel (refereegranskat)abstract
- The chromosome position of the Cd36 insert was determined by FISH in two rat transgenic lines (SHR/Ola-TgN(EF1aCd36)10Ipcv (SHR-TG10) and SHR/Ola-TgN(EF1aCd36)19Ipcv (SHR-TG19). The Cd36 transgene construct labelled with digoxigenin-11-dNTP was used as a probe in the FISH analysis. In accord with the previous finding that the SHR-TG10 harbours 6-8 copies of the transgene, the signals from both metaphase and interphase nuclei of SHR-TG10 preparations were rather strong and the probe hybridized to both copies of chromosome 1 at band q55. The probe hybridization to SHR-TG19 metaphase preparations also showed homozygosity of the transgene with localization of both copies to chromosome 11 at band q11. The signals were distinct but much weaker compared to the SHR-TG10, which again is in accord with the fact that the SHR-TG19 line harbours only a single copy of the transgene. In order to look for a possible impact of the insertion site neighbourhood upon the transgene phenotypic effect, we performed linkage mapping of the transgene in the SHR-TG19 line. By linkage mapping, the placement of the transgene to the proximal part of RNO11 was confirmed, the critical interval being 4 cM between D11Rat20 and D11Rat21, in good agreement with the RH map. Within the close neighbourhood of the inserted Cd36 transgene, there are several genes known to be expressed in kidney, and so the influence of some regulatory sequences enhancing kidney expression of the Cd36 transgene can be envisaged.
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| 8. |
- Teneva, I, et al.
(författare)
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Cytotoxicity and apoptotic effects of microcystin-LR and anatoxin-a in mouse lymphocytes
- 2005
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Ingår i: Folia Biologica. - 0015-5500. ; 51:3, s. 62-67
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Tidskriftsartikel (refereegranskat)abstract
- There is an increasing amount of knowledge on the cytotoxic properties of cyanotoxins, but relatively little is known regarding their fine specificity and mechanisms of action. In this study, we investigated the influence of microcystin-LR and AnTx-a on mouse B- and T-lymphocyte subpopulations in vitro. Cyanotoxins significantly decreased the cell viability after 4 and 24 h, compared to the untreated control. After 24 h exposure to microcystin-LR and anatoxin-a, the viability of splenocytes dropped to 23% and 57%, respectively. Our data demonstrate that microcystin-LR induced apoptosis specifically in mouse B cells, probably via the B-cell antigen receptor and mitochondrial pathway, while the T cells were not affected. AnTx-a showed cytotoxic effects on both lymphocyte subpopulations, but the effects were driven by mechanisms different from apoptosis. These findings demonstrate that the cyanotoxins could cause cytotoxic alterations in a variety of cell types different from the major targets, operating via distinct mechanisms.
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