Colony-Forming Ability and Residual Foci of DNA Repair Proteins in Human Lung Fibroblasts Irradiated with Subpicosecond Beams of Accelerated Electrons.

We performed a comparative study of the colony-forming ability and the number of residual foci of DNA repair proteins in cultured human lung fibroblasts (MRC-5 cell line) after exposure to subpicosecond beams of accelerated electrons with an energy of 3.6 MeV and quasi-continuous radiation (accelerated electrons with an energy of 4 MeV and X-rays). The yield of damages causing reproductive cell death after pulsed subpicosecond radiation exposure was higher by ~1.8 times than after quasi-continuous radiation exposure. The quantitative yield of residual γH2AX foci (phosphorylated H2AX histone, a protein marker of DNA double breaks) in cells irradiated with subpicosecond beams of accelerated electrons was shown to be ~2.0- 2.5-fold higher than in cells irradiated with quasi-continuous beams of accelerated electrons.

Proline-rich polypeptide-1 protects the cells in vitro from genotoxic effects of mitomycin C.

A new proline-rich polypeptide (PRP-1) has been earlier shown to possess a broad spectrum of biological activities and seems to be a potential medicine. The potential genotoxic properties of PRP-1 and protective effect of PRP-1 against genotoxic action of Mitomycin C (MMC) were analyzed in details in the present work. DNA and chromosome damages were studied in KCL-22 cell line of human myeloid leukemia by the Comet assay and micronucleus induction test, respectively. The results suggest that DNA damages are, at least partly, transient and reparable. PRP-1 at the doses 0.5-2.0 microg/ml does not possess genotoxic activity. Moreover, this peptide expresses both preventive and therapeutic effects against MMC-induced DNA damage. Pre-treatment of cells with PRP-1 also prevents the appearance of daughter cells bearing as heavy MMC-induced DNA/chromosome damages as MNs. Thus, the polypeptide studied is able to protect the cells from genotoxic action of MMC. This defense includes not only DNA but also heritable chromosome damage in post-mitotic cells. Possible mechanisms of PRP-1 protective action are discussed.

Morpho­functional study of the hypothalamic proline­rich polypeptide apoptotic activity against mouse Ehrlich ascites carcinoma.

A new type of bioactive polypeptides of the neurosecretory hypothalamus called proline­rich peptides (PRPs), which are isolated from bovine neurosecretory granules of the neurohypophysis, are synthesized in the form of a common precursor protein (neurophysin vasopressin­associated glycoprotein). Proline­rich polypetide 1 (PRP­1; also known as galarmin) is comprised of 15 amino acids residues, and has been suggested to possess anti­neurodegenerative, immunoregulatory, hematopoietic, antimicrobial and antitumor properties. The cytostatic, antiproliferative effect of PRP­1 was demonstrated in the human chondrosarcoma JJ012 and triple negative breast carcinoma MDA MB 231 cell lines. PRP­1 action is disease and tissue specific. To further explore the antitumorigenic and possible cytotoxic effects of PRP­1, a morpho­functional study on the effect of PRP­1 on a mouse Ehrlich ascites carcinoma (EAC) model was conducted. The PRP­1­induced morphological features of EAC cells confirmed the apoptotic nature of PRP­1, as manifested by cell shrinkage, membrane blebbing, chromosome condensation (pyknosis) and nuclear fragmentation (karyorrhexis). The effect of PRP­1 on the number of tumor cells incubated for 24 h and their viability in trypan blue­stained samples lead to a 44% reduction in the number of viable cells on day 11 post­inoculation vs. 22% inhibition of viable cells after PRP­1 treatment (0.1 µg/ml) on day 7 post­inoculation. Apoptosis experiments using an Annexin V­cyanine 3 apoptosis detection kit indicated that 24 h incubation with 0.1 µg/ml PRP­1 caused a significant increase in the number of apoptotic cells, reaching 50.33%, compared to 8.33% in the sample control on day 7 post­inoculation.

Clastogenecity evaluation of water of Lake Sevan (Armenia) using Tradescantia micronucleus assay.

The clastogenic effects of water samples in seven locations of Lake Sevan (Armenia) with the application of Trad-MCN (micronuclei) bioassay using Tradescantia (clone 02) were investigated. A significant increase in the frequency of micronuclei in tetrads of pollen microspores and tetrads with micronuclei exposed to the test samples compared to the control has been revealed. A multivariate analysis indicated linkage between the frequencies of occurrence of micronuclei in the cells and Ni and Co ions. The results were compared with the endpoints of another Tradescantia-based test system (stamen hair mutation test) performed on the same water samples and generation of the plant: occurrences of micronuclei in sporogenic cells coincided with that of non-surviving stamen hair.

Assessment of mutagenicity of water from Lake Sevan, Armenia with application of Tradescantia (clone 02).

For many decades water resources in Armenia have been affected by anthropogenic activity, therefore, a regular bioindication of genotoxic effects of the water bodies is desirable. The genotoxicity of water samples collected from different parts of Lake Sevan were assessed by means of Trad-SHM (stamen hair mutation) assay using Tradescantia (clone 02). Here we report a significant increase in the frequency of somatic mutations and morphological changes in the Tradescantia inflorescences exposed to the water samples compared to the control. The somatic mutations (recessive mutation and white mutation events) were mostly linked to the concentration of Al, Ni, As, Co and Pb in Artanish, Tsapatakh and Karchaghbyur, Noradus, Martuni and Litchk, while morphological changes (non-surviving hairs) were related to Co level in Tsapatakh and Karchaghbyur. The results obtained show that Lake Sevan contains substances which may cause genotoxicity and teratogenicity in Tradescantia and probably also in aquatic animals. The results also show that Trad-SHM assay can be used for monitoring natural resources.

Multicolor-FISH applied to resolve complex chromosomal changes in a case of T-ALL (FAB L2).

We report on a patient with a clinically diagnosed acute lymphoblastic leukemia (ALL) with partial unrecorded complex translocation events especially involving chromosomes 5, 9 and 18. At the GTG-band level the karyotype was abnormal in 20% of the analyzed cells. The complex karyotype was studied in more detail by spectral karyotyping (SKY) and multicolor banding (MCB) to characterize it in more detail. Thus, the karyotype could be described very accurately and in summary three different clones were detected, reflecting a high rate of karyotypic evolution in this patient.