[The cytogenetic study of established Syrian hamster cell lines. I. A comparative analysis of the karyotypes of the BHK-21 (C-13) sublines]. / Tsitogeneticheskoe issledovanie postoiannykh kletochnykh linii siriiskogo khomiachka. I. Sravnitel'nyi analiz kariotipov kletochnykh sublinii BHK-21 (C-13).

Karyotypes of eight BHK-21 (C-13) cell sublines, obtained from a variety of sources and available in the cell culture collection of our Institute, have been studied using G- and C-banding, and silver staining of chromosomes. These sublines with similar modal numbers of chromosomes (40-44) are found to vary essentially in composition of both normal chromosomes and markers. In spite of the fact that many markers are constant in several cell sublines, it was impossible to determine the marker chromosomes typical of BHK-21 (C-13) cell by analogy with those typical of HeLa cells. Our studies have shown that BHK-21 (C-13) cells exhibit nonrandom chromosomal alteration involving heterochromatic regions, particularly long arms of X- and Y-chromosomes and centromeric regions of 1, 3, 6 and X-chromosomes. Deletions of Xq, Yq and heterochromatic short arms of autosomes have also been observed. The markers more commonly consist of the material of chromosomes 1, 2, 3, 4, 5, 8, 9, 16, 17, 18, 19, X and Y.

[The cytogenetic study of established Syrian hamster cell lines. II. A comparative analysis of the karyotypes of cell lines HaK, CER and BHK-21 (C-13)]. / Tsitogeneticheskoe issledovanie postoiannykh kletochnykh linii siriiskogo khomiachka. II. Sravnitel'nyi analiz kariotipov kletochnykh linii HaK, CER i BHK-21 (C-13).

A comparative cytogenetic investigation of the Syrian hamster HaK, CER cell lines and BHK-21 (C-13) sublines was undertaken using G- and C-banding, and silver staining of chromosomes. BHK-21 (C-13) cell sublines were found to have diploid associated chromosome sets, whereas HaK and CER cell lines are characterized with triploid and tetraploid associated chromosome sets, resp. In sum, in all the analysed cell lines 100 marker chromosomes were identified, with 85 ones having unique morphology. The finding indicates a nonaccidental appearance of lesions for normal chromosomes in forming markers. Another arrangement of "hot break-points" on chromosomes is more typical of HaK and CER cell lines, than of BHK-21 (C-13) sublines. The localization of "hot break-points" on chromosomes in BHK-21 (C-13) sublines is specific of the Syrian hamster cells transformed with oncogenic viruses.

[The cytogenetic study of established Syrian hamster cell lines. III. An analysis of the NOR-marker chromosomes in Syrian hamster cell cultures by using differential chromosome Ag-->G restaining]. / Tsitogeneticheskoe issledovanie postoiannykh kletochnykh linii siriiskogo khomiachka. III. Analiz iadryshkoobrazuiushchikh markernykh khromosom kul'tur kletok siriiskogo khomiachka s pomoshch'iu differentsial'nogo Ag-->G-pereokrashivaniia khromosom.

Using silver staining --> G-banding restaining procedure it was found that the Syrian hamster chromosomes had nucleolar organizers on subtelocentric chromosomes 2, 6, 9, 10 and 13, and on acrocentric chromosomes 16, 17 and 19. In this case, NORs may be recognized only on one of homologous chromosomes, and no more than 9 NO-chromosomes may be found in one metaphase plate. In HaK, BHK-21 (C-13) BKK and BHK-21 (C-13) C cell lines, chromosomes 6, 9, 16, 17 and 19 have NORs, and in each line there are specific marker chromosomes with NOR. The markers consist of the material of chromosomes 6, 9, 16 and 17, with only chromosomes 16 and 17 being incorporated into rearrangements by their NORs. The silver staining --> G-banding restaining procedure makes possible not only identification of NO-chromosomes, but also refinement of the marker origins.

[Effective synthesis and cloning of the human interleukin-2 gene and its analog: expression of the interleukin-2 gene in E. coli cells]. / Effektivnyi sintez i klonirovanie gena interleikina-2 cheloveka i egoanaloga: ékspressiia v kletkakh E. coli gena interleikina-2.

Artificial DNA fragments encoding human interleukin-2 (133 a.a.) and its analogue (deletion of 14 C-terminal a.a.) were prepared by means of the DNA polymerase I mediated extension of synthetic polynucleotides having short overlapping sequences at their 3'-ends. The fragments were cloned in specially designed pFH-type plasmids and then excised by the FokI and other restriction endonucleases to yield the subfragments with the structurally predetermined 5'-unique cohesive ends. The complete synthetic gene was constructed by one or two-step ligation. The expressed IL-2 was tested by analysing the T-cell proliferation activity of E.coli crude lisates containing the pEXIL2 expression plasmid.

[A karyotype study of the Vero cell line cultured long term in a monolayer by static and roller methods]. / Issledovanie kariotipa kletok linii Vero, dlitel'no kul'tiviruemykh v monosloe staticheskim i rollernym sposobami.

A cytogenetic investigation of Vero cells, before and after adaptation to the medium containing a cattle serum, was carried out by methods of differential chromosome staining. Under these conditions, both the modal number of chromosomes (from 58 to 55) and the karyotype structure, namely the copy number of normal chromosomes and the marker composition were shown to change. The Vero cell karyotype stability was studied in the continued culture by the static (50 passages) and roll-bottle (37 passages) methods. The quantitative changes (the rising percentage of diploid cells, and the change of cell fraction involving the modal number of chromosomes) were shown to occur in spite of the chromosome composition stability, which limits the time of using Vero cells as a substrate for preparation of vaccines.

[Cytogenetic characteristics of the cell line BHK-21 (C-13) and three of its clones]. / Tsitogeneticheskaia kharakteristika kletochnoi linii BHK-21 (C-13) i trekh ee klonov.

Cell clones (C-9, C-24, C-36) of the cell line BHK-21 (C-13) were obtained and characterized. Compared to the original line, cells of these clones are larger in size, display an increased content of nuclear DNA and have more chromosomes. The G-bands were obtained by Giemsa staining following mild trypsin treatment. Marker chromosomes were determined in the original cell line BHK-21 (C-13) and in its large-cell clones. All the clones obtained are polyploid.

[The protein-synthesizing apparatus of a BHK-21 (C-13) cell culture and of its large-cell clone C-9]. / Issledovanie beloksinteziruiushchego apparata kul'tury kletok VNK-21 (C-13) i ee krupnokletochnogo klona C-9.

Cell line BHK-21 (C-13) and its large cell clone C-9 differ in morphology, karyotype and cultural properties. Clone C-9 is polyploid. It has been shown that C-9 clone cells display 2.5-3-fold excess in the nucleolus organizer region (NOR) in chromosomes, and 2-3 times higher intensity of protein synthesis and of ribosomal material content compared to the original line. Data of sedimentation analysis and of protein synthesis activity of the total ribosomal material in the cell-free translational system from rabbit reticulocytes allow to conclude that the quantity and size of polyribosomes in C-9 cells are higher than in cells of the original line. Apparently, the quantity of NOR-chromosomes reflect the activity of protein translation system of investigated cells.