The relative length of telomeres measured in peripheral blood leukocytes is a commonly used system marker for biological aging and can also be used as a biomarker of cardiovascular aging. However, to what extent the telomere length in peripheral leukocytes reflects telomere length in different organ tissues is still unclear. Therefore, we have measured relative telomere length (rTL) in twelve different human tissues (peripheral blood leukocytes, liver, kidney, heart, spleen, brain, skin, triceps, tongue mucosa, intercostal skeletal muscle, subcutaneous fat, and abdominal fat) from twelve cadavers (age range of 29 week of gestation to 88 years old). The highest rTL variability was observed in peripheral leukocytes, and the lowest variability was found in brain. We found a significant linear correlation between leukocyte rTL and both intercostal muscle (R=0.68, P<0.02) and liver rTL (R=0.60, P<0.05) only. High rTL variability was observed between different organs from one individual. Furthermore, we have shown that even slight DNA degradation (modeled by sonication of genomic DNA) leads to false rTL shortening. We conclude that the rTL in peripheral leukocytes is not strongly correlated with the rTL in different organs., D. Dlouha, J. Maluskova, I. Kralova Lesna, V. Lanska, J. A. Hubacek., and Obsahuje bibliografii
The karyotype of bream Abramis brama was analysed by means of C-banding, replication banding, DAPI fluorescent staining and in situ hybridisation with 18S rDNA and telomeric probes. The use of the in vivo 5-bromodeoxyuridine incorporation technique enabled the induction of replication bands of the RBA type in the karyotype. C-bands corresponded to late replicated chromosome regions. 18S rDNA clusters were found on one chromosome pair. Telomeric sequences were observed only on ends of chromatids. The karyotype morphology and NOR phenotype of A. brama are very similar to those found in other species of the leuciscine cyprinids karyotyped so far.
The present paper reports some cytogenetic peculiarities observed in the Ag-NORs of Pamphagus ortolaniae chromosomes, the unusual behaviour of ribosomal sites after silver staining and the intense Ag-positive reaction of centromeric regions at spermatogonial metaphase and spermatocyte metaphase I and II. Moreover, a conclusive identification and localization of all the ribosomal clusters is provided by using heterologous rDNA FISH on spermatocyte chromosomes. 18S-28S rDNA mapped on a single chromosome pair and resulted multiclustered along the chromosomal body in three distinct serial regions, r1, r2 and r3. Surprisingly, these areas were scarcely (r1) or never (r2 and r3) detectable by silver impregnation. As in other Orthoptera and many groups of arthropods, FISH with the pentamer (TTAGG)n as the probe labelled the telomeres of all chromosomes.