Cytotoxic Evaluation of Eurycoma longifolia Jack Root Extract on Chromosome Aberrations in Human Lymphocytes In vitro

This study aimed to investigate chromosomal aberrations of Eurycoma longifolia Jack (EL) root extract in human lymphocytes in vitro. Human whole blood was cultured in medium solution that treated with distilled water, 20% DMSO, extract of EL roots at the concentration of 2.5, 5, 10, 20, 40, 80 µg/mL (extracted with distilled water and ethanol), and nontreated (blank: only culture medium and whole blood). All experiments were cultured for 72 hours in the 37°C incubator. The effects of EL roots extract on cytotoxicity were compared with the control groups including the blank, distilled water, and 20% DMSO. This study found that EL root extract significantly decreased metaphase cell number and increased chromosome aberrations dose dependent manner (p<0.01). The 7 types of chromosome aberration that were observed consisted of dicentric chromosome, single chromatid breaks, isochromatid break, isochromatid gap, single chromatid gap, fragmentation, and deletion. The dicentric chromosome was the most common chromosomal aberrations type that was treated with EL root extract both distilled water and ethanol. Moreover, the ethanolic extract of EL root was more effective to stimulate chromosome aberrations compared to the water extract of EL root (the deletion and fragmentation were not found in the water extract of EL root). This study demonstrated that the phytochemicals of EL root extract had cytotoxicity effect (decreased metaphase cells and increase cells death) and genotoxic effect (increased chromosomal aberrations. The use of EL root crude extract with distilled water is therefore safer for cells. However, when EL is used at high levels, it may lead to the inhibition of cell division process and cause side effects (toxicity). EL extracts consist of various phytochemicals with different properties and dosages, thus more studies should be conducted on the effect of those substances on cytotoxicity, especially their effects on genotoxicity humans.

Comparative study of four Mystus species (Bagridae, Siluriformes) from Thailand: insights into their karyotypic diversity

Karyotypes of four catfishes of the genus Mystus Scopoli, 1777 (family Bagridae), M. atrifasciatus Fowler, 1937, M. mysticetus Roberts, 1992, M. singaringan (Bleeker, 1846) and M. wolffii (Bleeker, 1851), were analysed by conventional and Ag-NOR banding as well as fluorescence in situ hybridization (FISH) techniques. Microsatellite d(GC)15, d(CAA)10, d(CAT)10 and d(GAA)10 repeat probes were applied in FISH. The obtained data revealed that the four studied species have different chromosome complements. The diploid chromosome numbers (2n) and the fundamental numbers (NF) range between 52 and 102, 54 and 104, 56 and 98, or 58 and 108 in M. mysticetus, M. atrifasciatus, M. singaringan or M. wolffii, respectively. Karyotype formulae of M. mysticetus, M. atrifasciatus, M. singaringan and M. wolffii are 24m+26sm+4a, 26m+24sm+2a, 24m+18sm+14a and 30m+22sm+6a, respectively. A single pair of NORs was identified adjacent to the telomeres of the short arm of chromosome pairs 3 (metacentric) in M. atrifasciatus, 20 (submetacentric) in M. mysticetus, 15 (submetacentric) in M. singaringan, and 5 (metacentric) in M. wolffii. The d(GC)15, d(CAA)10, d(CAT)10 and d(GAA)10 repeats were abundantly distributed in species-specific patterns. Overall, we present a comparison of cytogenetic and molecular cytogenetic patterns of four species from genus Mystus providing insights into their karyotype diversity in the genus

Genomic Organization of Repetitive DNA Elements and Extensive Karyotype Diversity of Silurid Catfishes (Teleostei: Siluriformes): A Comparative Cytogenetic Approach

International audienceThe catfish family Siluridae contains 107 described species distributed in Asia, but with some distributed in Europe. In this study, karyotypes and other chromosomal characteristics of 15 species from eight genera were examined using conventional and molecular cytogenetic protocols. Our results showed the diploid number (2n) to be highly divergent among species, ranging from 2n = 40 to 92, with the modal frequency comprising 56 to 64 chromosomes. Accordingly, the ratio of uni- and bi-armed chromosomes is also highly variable, thus suggesting extensive chromosomal rearrangements. Only one chromosome pair bearing major rDNA sites occurs in most species, except for Wallago micropogon, Ompok siluroides, and Kryptoterus giminus with two; and Silurichthys phaiosoma with five such pairs. In contrast, chromosomes bearing 5S rDNA sites range from one to as high as nine pairs among the species. Comparative genomic hybridization (CGH) experiments evidenced large genomic divergence, even between congeneric species. As a whole, we conclude that karyotype features and chromosomal diversity of the silurid catfishes are unusually extensive, but parallel some other catfish lineages and primary freshwater fish groups, thus making silurids an important model for investigating the evolutionary dynamics of fish chromosomes