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.

A comparative cytogenetic study of Hypsibarbus malcolmi and H. wetmorei (Cyprinidae, Poropuntiini)

Cyprininae are a highly diversified but demonstrably monophyletic lineage of cypriniform fishes. Here, the karyotype and chromosomal characteristics of Hypsibarbus malcolmi (Smith, 1945) and H. wetmorei (Smith, 1931) were examined using conventional, nucleolus organizing regions (NORs) and molecular cytogenetic protocols. The diploid chromosome number (2n) of H. malcolmi was 50, the fundamental number (FN) was equal to 62, and the karyotype displayed 8m + 4sm + 38a with NORs located at the centromeric and telomeric positions of the short arms of chromosome pairs 1 and 2, respectively. 2n of H. wetmorei was 50, FN 78, karyotype 14m + 14sm + 22a with the NORs at the telomeric position of the short arm of chromosome pair 2. 2n and FN in males and females were identical. Fluorescence in situ hybridization using different microsatellite motifs as probes also showed substantial genomic divergence between both studied species. In H. wetmorei, (CAG)n and (CAC)n microsatellites accumulated in the telomeric regions of all chromosomes, while in H. malcolmi, they had scattered signals on all chromosomes. Besides, the (GAA)n microsatellites were distributed along all chromosomes of H. malcolmi, but there was a strong hybridization pattern in the centromeric region of a single pair in H. wetmorei. These cytogenomic difference across the genomes of these Hypsibarbus Rainboth, 1996 species are markers for specific evolutionary differentiation within these two species

Cytogenetics, genomics and biodiversity of the South American and African Arapaimidae fish family (Teleostei, Osteoglossiformes)

<div><p>Osteoglossiformes represents one of the most ancestral teleost lineages, currently widespread over almost all continents, except for Antarctica. However, data involving advanced molecular cytogenetics or comparative genomics are yet largely limited for this fish group. Therefore, the present investigations focus on the osteoglossiform family Arapaimidae, studying a unique fish model group with advanced molecular cytogenetic genomic tools. The aim is to better explore and clarify certain events and factors that had impact on evolutionary history of this fish group. For that, both South American and African representatives of Arapaimidae, namely <i>Arapaima gigas</i> and <i>Heterotis niloticus</i>, were examined. Both species differed markedly by diploid chromosome numbers, with 2n = 56 found in <i>A</i>. <i>gigas</i> and 2n = 40 exhibited by <i>H</i>. <i>niloticus</i>. Conventional cytogenetics along with fluorescence <i>in situ</i> hybridization revealed some general trends shared by most osteoglossiform species analyzed thus far, such as the presence of only one chromosome pair bearing 18S and 5S rDNA sites and karyotypes dominated by acrocentric chromosomes, resembling thus the patterns of hypothetical ancestral teleost karyotype. Furthermore, the genomes of <i>A</i>. <i>gigas</i> and <i>H</i>. <i>niloticus</i> display remarkable divergence in terms of repetitive DNA content and distribution, as revealed by comparative genomic hybridization (CGH). On the other hand, genomic diversity of single copy sequences studied through principal component analyses (PCA) based on SNP alleles genotyped by the DArT seq procedure demonstrated a very low genetic distance between the South American and African Arapaimidae species; this pattern contrasts sharply with the scenario found in other osteoglossiform species. Underlying evolutionary mechanisms potentially explaining the obtained data have been suggested and discussed.</p></div

Contribution to the knowledge of Rhaphidophorinae (Orthoptera: Ensifera: Rhaphidophoridae) from Thailand: three genera Neorhaphidophora, Eurhaphidophora and Minirhaphidophora

Dawwrueng, Pattarawich, Gorochov, Andrei V., Tanomtong, Alongklod, Suwannapoom, Chatmongkon (2020): Contribution to the knowledge of Rhaphidophorinae (Orthoptera: Ensifera: Rhaphidophoridae) from Thailand: three genera Neorhaphidophora, Eurhaphidophora and Minirhaphidophora. Zootaxa 4853 (2): 235-253, DOI: https://doi.org/10.11646/zootaxa.4853.2.