Dietary Methionine Deficiency Enhances Genetic Instability in Murine Immune Cells

G-Banding and Molecular Cytogenetics Detect Novel Translocations and Cryptic Aberrations in Human Immortal Endothelial Cells

Endothelial cells (ECs) maintain vessel tone and barrier integrity, regulate blood homeostasis, and prevent the extravasation of leukocytes under normal physiological conditions. Because of the limited lifespans and batch-to-batch differences with respect to the genetic make-up of primary ECs, established immortal EC lines are extensively used for studying endothelial biology. To address this issue, the immortal endothelial cell line EA.hy926 was developed by fusing primary human umbilical vein endothelial cells (HUVECs) with human lung carcinoma A549 cells. EA.hy926 cells share a number of similar endothelial properties with HUVECs and are considered the immortal counterpart to primary HUVECs. However, the cytogenetic integrity of EA.hy926 cells is not fully elucidated. We characterized EA.hy926 cells with conventional G-banding and molecular cytogenetic techniques such as spectral karyotyping and subtelomeric fluorescence in situ hybridization. Cytogenetic analysis revealed an array of numerical and stable structural chromosomal rearrangements including one deletion, one duplication, one isochromosome, seven simple translocations, and five complex translocations in Ea.hy926 cells. These findings will advance comprehension of EA.hy926 cell biology and augment future endothelial studies, specifically in comparison studies between HUVECs and EA.hy926 cells.

Protocol for preparation and staining of chromosomes isolated from mouse and human tissues for conventional and molecular cytogenetic analysis

The study of chromosomes without or with molecular DNA probes provides crucial insight for understanding research findings, as well as refining diagnosis, prognosis, and therapeutics in clinical settings. Here, we present a protocol for chromosome preparation, conventional G-banding, locus-specific fluorescent in situ hybridization, and spectral karyotyping for both mouse and human samples. This protocol optimizes the preparation of chromosomes from mouse and human cells for subsequent conventional and molecular cytogenetic analysis. For complete details on the use and execution of this protocol, please refer to Binz et al.1.

Molecular Cytogenetics Reveals Mosaicism in Human Umbilical Vein Endothelial Cells

Primary human umbilical vein endothelial cells (HUVECs) are consistently the most reliable in vitro model system for studying the inner lining of blood and lymphatic vessels or the endothelium. Primary human cells originate from freshly isolated tissues without genetic manipulation and generally show a modal number of 46 chromosomes with no structural alterations, at least during early passages. We investigated the cytogenetic integrity of HUVECs with conventional (G-banding) and molecular cytogenetic methods (spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH)). Our G-band data shows two X-chromosomes, confirming these HUVECs originate from a female donor. Notably, some cells consistently exhibit an unfamiliar banding pattern on one X chromosome toward the distal end of the long arm (Xq). Our FISH analysis confirms that approximately 50% of these HUVECs have a deletion of the Xq terminal region. SKY analysis indicates that the deleted region is apparently not integrated into any other chromosome. Finally, we demonstrated the presence of a similar Xq deletion in the daughter cell line, EA.hy926, which was generated by fusing HUVECs with A549 (a thioguanine-resistant clone of adenocarcinomic human alveolar basal epithelial cells). These findings will advance comprehension of HUVECs biology and will augment future endothelial studies.

Fish feed can show genotoxic damage

The present study was carried out to evaluate the genotoxic potential of nutritional quality of feed, using erythrocytic nuclear abnormalities assay in Nile tilapia and its correlation with available nutrients and common fish growth biomarkers. For this, ten feeds commercialized in Brazil were assessed on digestibility and performance assays with triplicate groups. Venipuncture of the caudal vein for abnormalities analyzed was performed 102 days after the fish were fed with the commercial feed twice a day, to apparent satiation. Nuclear abnormalities were analyzed in blood smears. Principal component analysis and correlation matrix were used to carry out an exploratory analysis of correlation between frequency of abnormalities and performance parameters or available nutrients. The frequency of abnormalities in erythrocytes of Nile tilapia, fish performance, and digestibility were feed-dependent. It was observed correlations between the frequency of most abnormalities and performance parameters or content of nutrients. The frequency of kidney-shaped (6.23 ± 4.14), bud nuclei (2.99 ± 1.95), bridge nuclei (0.53 ± 0.50), and binuclei (0.43 ± 0.59) was the highest in fish that also presented the worst performance among all treatments and correlated with digestible methionine. Micronucleus frequency (0.33 ± 0.49) was higher in fish from the same group that presented depressed feed intake and lower available zinc. Only one group presented vacuolated nuclei and the frequency of this abnormality was correlated with available phosphorus. The frequency of abnormalities in erythrocytes is a fish sensitive indicator of health and plays an important role as a complementary tool in the assessment of fish feeding. The variation in the frequency of nuclear abnormalities in erythrocytes obtained among fish fed with the different feeds allows the assertion that they contained genotoxic factors.