Cytotoxic and genotoxic evaluation of bisphenol S on onion root tips by Allium cepa and comet tests

Cyto-Genotoxic Assessment of Sulfoxaflor in Allium cepa Root Cells and DNA Docking Studies

Sulfoxaflor (SFX) is an insecticide that is commonly used for the control of sap-feeding insects. Since SFX is extensively applied globally, it has been implicated in the substantial induction of environmental toxicity. Therefore, in this study, Allium cepa roots have been employed to elucidate the potential cytogenotoxic effects of SFX in non-target cells by examination of mitotic index (MI), chromosomal aberrations (CAs), and DNA damage. Physiological effects of SFX were evaluated by A. cepa root growth inhibition assay, while cytogenotoxic effects were assessed by A. cepa ana-telophase and comet assay. Moreover, DNA binding affinity and binding mode of SFX were examined using molecular docking simulations to shed light on the genotoxic mechanism of action. The half maximal effective concentration (EC50) on the growth of A. cepa cells calculated for SFX was found as 500 mg/L. Moreover, dose- and time-dependent decrease in MI, increase in CAs (disturbed ana-telophase, chromosomal laggards, stickiness, and anaphase chromosome bridge) and DNA damage were observed by the exposure of A. cepa root tips to SFX after 24-, 48-, 72-, and 96-h treatment periods. A 6-bp double-stranded DNA structure containing two intercalation sites (PDB ID: 1Z3F) was used for docking studies. According to DNA docking results, SFX exhibited an energetically more favorable binding affinity with DNA (ΔG = -5.05 kcal/mol) compared with the experimental mutagen methyl methanesulfonate (MMS) (ΔG = -2.94 kcal/mol), and preferentially snugly fits into the minor groove of DNA possessing an intercalation gap, thus, providing valuable mechanistic data into the formation of chromosome aberrations and DNA fragmentation induced by this pesticide in A. cepa.

Comparative carcinogenic and non-carcinogenic health risks, and cytogenotoxicity of wastewaters from natural and artificial fishponds indiscriminately disposed in Nigeria

As the demand for fish increases, the amount of wastewater generated from fishponds is also increasing with potential environmental and public health effects from their indiscriminate disposal. This study aimed at comparative analyses of the physicochemical and heavy metal constituents and potential DNA damage by wastewaters from natural and artificial fishponds using Allium cepa assay. A. cepa were grown on 3.13, 6.25, 12.5, 25.0, and 50.0% (v/v; wastewater/tap water) concentrations of each wastewater. At 48 and 72 h, respectively, genotoxic and root growth inhibition analyses were carried out on the exposed onions. The onion root tips exposed to wastewaters showed a significant (P < 0.05) inhibition of root growth and cell division in a concentration-dependent manner. Additionally, chromosomal abnormalities like spindle disturbances, sticky chromosomes, micronucleus, bridges, and binucleated cells were observed in the exposed onions and their induction was higher significantly relative to the negative control. Generally, wastewater from the natural fishpond caused higher chromosomal aberrations than the wastewater from artificial fishpond. It is our belief that the cytotoxicity and genotoxicity observed in the onions were primarily caused by heavy metals like Cr, Cd, Fe, Pb, Cu, and Zn found in the wastewaters. These metals also showed a significant carcinogenic and non-carcinogenic risks in children and adults with Cd as the highest contributor to these detrimental risks. Ingestion route was the major exposure route to the toxic metals in these wastewaters. Wastewater from the natural fishpond showed a higher health risk than the wastewater from the artificial fishpond. These findings suggest that the wastewaters from natural and artificial fishpond contain compounds that might induce cytogenotoxicity in exposed organisms.

Ascorbic acid regulates in vitro and in vivo toxicogenetic effects of hydroxyurea on eukaryotic cells

Hydroxyurea (HU) exerts unique and diverse biological effects as an anti-leukemic agent, irradiation sensitizer, and HbS inducer in patients with sickle cell anemia. Herein, we assessed the potential toxicogenic and/or oxidant effects of hydroxyurea associated with ascorbic acid by in vivo examinations in Allium cepa and human cancer cells and systemically on mice tissues. Growing A. cepa roots and HCT-116 colorectal tumor cells were examined after HU and HU plus ascorbic acid exposure. DNA damage and antioxidant enzymatic activity were quantified in peripheral blood mononuclear cells (PBMC), bone marrow leukocytes and livers of mice after 7 day-HU treatment (7.5, 15 and 30 mg/kg/day) and Vitamin C 2 μM. Hydroxyurea presented toxic effects on meristematic Allium cepa cells, causing chromosomal abnormalities and reduction of mitotic index, killed HCT-116 colorectal carcinoma cells and induced DNA injuries upon mice cells (hepatocytes, bone marrow leukocytes and PBMC). Simultaneously, hydroxyurea decreased levels of CAT and GSH activities and expand lipid peroxidation. All these biochemical and physiological changes were ameliorated when associated with ascorbic acid, indicating it restored antioxidant enzymes, decreased MDA levels, removed peroxides and, consequently, presented cytoprotection against HU-provoked cellular damage in normal cells. On the other hand, antioxidants compounds may interfere on effectiveness of HU during anticancer chemotherapies.

Effects of Indigo Carmine on Growth, Cell Division, and Morphology of Allium cepa L. Root Tip

Indigo carmine has a variety of uses in foods, textiles, medicine, pharmaceuticals, and cosmetics. There are studies reporting the toxic potential of indigo carmine on human health and the environment. In this study, we investigated the cytogenotoxic effects of indigo carmine using apical root cells of Allium cepa. Allium cepa bulbs were subjected to four treatments with indigo carmine (0.0032, 0.0064, 0.0125, and 0.2 mg/mL) and to ultrapure water as a control. After 5 days, root growth, root length, mitotic index, mitotic inhibition, chromosomal anomalies, and cell morphology were analyzed. According to our results, a decrease in root length and mitotic index was observed at all concentrations of indigo carmine. Additionally, several types of chromosomal abnormalities were observed, such as disturbed metaphase, sticky chain metaphase, anaphase bridge, and laggard chromosomes. Moreover, histological observation indicated that indigo carmine induces alterations in various components of root tip tissue, such as deformation and alteration of the cell wall, progressive condensation of chromatin, shrinkage of the nuclei, and an increase in the number of irregularly shaped nuclei and nuclear fragments. Our results indicate that the tested concentrations of indigo carmine may have toxic effects and raise concerns about its intensive use in many fields.

Effect of Melissa officinalis L. leaf extract on manganese-induced cyto-genotoxicity on Allium cepa L

Although the antioxidant properties of Melissa officinalis extract (Mox) are widely known, little work has focused on its protective capacity against heavy metal stress. The primary objective of this study was to determine the potential of Mox to mitigate manganese (II) chloride (MnCI2)-induced cyto-genotoxicity using the Allium and comet assays. Physiological, genotoxic, biochemical and anatomical parameters as well as the phenolic composition of Mox were examined in Allium cepa (L.). Application of 1000 µM MnCl2 reduced the rooting percentage, root elongation, weight gain, mitotic index and levels of chlorophyll a and chlorophyll b pigments compared to the control group. However, it increased micronuclei formation, chromosomal abnormality frequencies, tail DNA percentage, proline amount, lipid peroxidation level and meristematic damage severity. The activities of superoxide dismutase and catalase also increased. Chromosomal aberrations induced by MnCl2 were fragment, sticky chromosome, vagrant chromosome, unequal distribution of chromatin and bridge. Application of 250 mg/L Mox and 500 mg/L Mox along with MnCl2 significantly alleviated adverse effects dose dependently. The antioxidant activity bestowed by the phenolic compounds in Mox assisted the organism to combat MnCl2 toxicity. Consequently, Mox exerted remarkable protection against MnCl2 toxicity and it needs to be investigated further as a potential therapeutic option.

Sodium Alginate-Based MgO Nanoparticles Coupled Antibiotics as Safe and Effective Antimicrobial Candidates against Staphylococcus aureus of Houbara Bustard Birds

Alternative and modified therapeutic approaches are key elements in culminating antibiotic resistance. To this end, an experimental trial was conducted to determine the cytotoxicity and antibacterial potential of composites of magnesium oxide (MgO) nanoparticles and antibiotics stabilized in sodium alginate gel against multi-drug-resistant Staphylococcus aureus isolated from a houbara bustard. The characterization of preparations was carried out using X-ray diffraction (XRD), scanning transmissible electron microscopy (STEM), and Fourier-transform infrared spectroscopy (FTIR). The preparations used in this trial consisted of gel-stabilized MgO nanoparticles (MG), gel-stabilized tylosin (GT), gel-stabilized ampicillin (GA), gel-stabilized cefoxitin (GC), gel-stabilized MgO and tylosin (GMT), gel-stabilized MgO and cefoxitin (GMC), and gel-stabilized MgO and ampicillin (GMA). The study presents composites that cause a lesser extent of damage to DNA while significantly enhancing mitotic indices/phases compared to the other single component preparations with respect to the positive control (methyl methanesulphonate). It was also noted that there was a non-significant difference (p > 0.05) between the concentrations of composites and the negative control in the toxicity trial. Studying in parallel trials showed an increased prevalence, potential risk factors, and antibiotic resistance in S. aureus. The composites in a well diffusion trial showed the highest percentage increase in the zone of inhibition in the case of GT (58.42%), followed by GMT (46.15%), GC (40.65%), GMC (40%), GMA (28.72%), and GA (21.75%) compared to the antibiotics alone. A broth microdilution assay showed the lowest minimum inhibitory concentration (MIC) in the case of GMA (9.766 ± 00 µg/mL), followed by that of GT (13.02 ± 5.64 µg/mL), GMC (19.53 ± 0.00 µg/mL), GA (26.04 ± 11.28 µg/mL), GMT (26.04 ± 11.28 µg/mL), MG (39.06 ± 0.00 µg/mL), and GC (39.06 ± 0.00 µg/mL). The study thus concludes the effective tackling of multiple-drug-resistant S. aureus with sodium-alginate-stabilized MgO nanoparticles and antibiotics, whereas toxicity proved to be negligible for these composites.

A scoping review of recent advances in the application of comet assay to Allium cepa roots

The comet assay is a sensitive method for the evaluation of DNA damages and DNA repair capacity at single-cell level. Allium cepa is a well-established plant model for toxicological studies. The aim of this scoping review was to investigate the recent application of the comet assay in Allium cepa root cells to assess the genotoxicity. To explore the literature a search was performed selecting articles published between January 2015 and February 2023 from Web of Science, PubMed, and Scopus databases using the combined search terms "Comet assay" and "Allium cepa". All the original articles that applied the comet assay to Allium cepa root cells were included. Of the 334 records initially found, 79 articles were identified as meeting the inclusion criteria. Some studies reported results for two or more toxicants. In these cases, the data for each toxicant were treated separately. Thus, the number of analyzed toxicants (such as chemicals, new materials, and environmental matrices) was higher than the number of selected papers and reached 90. The current use of the Allium-comet assay seems to be directed towards two types of approach: the direct study of the genotoxicity of compounds, mainly biocides (20% of analyzed compounds) and nano- and microparticles (17%), and assessing a treatment's ability to reduce or eliminate genotoxicity of known genotoxicants (19%). Although the genotoxicity identified by the Allium-comet assay is only one piece of a larger puzzle, this method could be considered a useful tool for screening the genotoxic potential of compounds released into the environment.

Modification of the drug resistance of emerging milk-borne pathogens through sodium alginate-based antibiotics and nanoparticles

Streptococcus agalactiae and Klebsiella pneumoniae are emerging as major milk-borne pathogens. Additionally, resistance to antibiotics of pathogens is of concern. Therefore, this study investigated the prevalence and drug resistance of S. agalactiae and K. pneumoniae in mastitis milk samples and assessed the antimicrobial potential of sodium alginate (G)-stabilized MgO nanoparticles (M) and antibiotics (tylosin [T] and ampicillin [A]) against both of these pathogens. A total of n = 200 milk samples from cattle were collected using purposive sampling, and standard microbiological approaches were adopted to isolate target bacteria. Parametric and non-parametric statistical tests were used to analyze the obtained data. Four preparations, GT (gel-stabilized tylosin), GA (gel-stabilized ampicillin), GTM (tylosin and MgO nanoparticles stabilized in gel), and GAM (ampicillin and MgO nanoparticles stabilized in gel), were evaluated against both bacteria through well diffusion and broth microdilution method. The analysis revealed that 45.24% (95/210) of the milk samples were positive for mastitis, of which 11.58% (11/95) were positive for S. agalactiae and 9.47% (9/95) were positive for K. pneumoniae. S. agalactiae had a significantly higher zone of inhibition (ZOI) than K. pneumoniae against penicillin, tetracycline, and amoxicillin, whereas the opposite was observed against imipenem and erythromycin. All gel (G)-based preparations showed an increase in the percentage of ZOI compared with antibiotics alone, with GTM presenting the highest of all, i.e., 59.09 and 56.25% ZOI compared with tylosin alone against S. agalactiae and K. pneumoniae, respectively. Similarly, in a broth microdilution assay, the lowest MIC was found for K. pneumoniae (9.766 ± 0.0 μg/mL) against GTM, followed by GT, GAM, and GA after incubation for 24 h. A similar response was noted for preparations against S. agalactiae but with a comparatively higher MIC. A significant reduction in MIC with respect to incubation time was found at 8 h and remained until at 20 h against both pathogens. The cytotoxicity of the MgO nanoparticles used in this study was significantly lower than that of the positive control. Overall, this study found that K. pneumoniae and S. agalactiae appeared higher in prevalence and antimicrobial resistance, and sodium alginate-based antibiotics and MgO nanoparticles were effective alternative approaches for tackling antimicrobial resistance.