Root Meristems Of Allium Cepa Research Articles

Evaluation of Physico-Chemical Parameters of Stream Water and Their Cytotoxic Effects on Allium Cepa Around Ibobo Coalmine, Kogi State, Nigeria

The Ibobo coal mine is an abandoned mine located in the middle belt of Nigeria and lies in the Ajali Formation within the Anambra Basin. The adjoining rivers and streams in this community serve as sources of water for human consumption and plant use. The study was conducted in January 2016 at the peak of the dry season. Major and trace elements were measured in the water samples collected and subjected to the following analysis; conductometry and electro-analytical techniques for physical parameters; titrimetry and spectrophotometry for anions; and flame atomic absorption spectrophotometry for the cations. Further study was carried out to evaluate the cytotoxic effects of the water samples from plants and other living organisms using the root meristems of Allium cepa (onion). This study revealed that the average concentrations of Iron (0.344mg/L), Lead (0.024 mg/L) and Cadmium (0.004 mg/L) are higher than the maximum permissible limits of Standard Organisation of Nigeria (SON) and World Health Organisation (WHO) guidelines for domestic and drinking water qualities. Water from the streams should, therefore, be discouraged for both domestic and agricultural purposes through public health awareness program. Keywords: Physico-chemical analysis, spectrophotometry, TDS, Allium cepa, Mamu Formation, Cytotoxic DOI : 10.7176/JEES/9-6-07 Publication date :June 30 th 2019

Appraisal of immediate and late effects of mobile phone radiations at 2100MHz on mitotic activity and DNA integrity in root meristems of Allium cepa.

The present study evaluated the potential of 2100MHz radiofrequency radiations to act as cytotoxic and genotoxic agent. Fresh onion (Allium cepa L.) roots were exposed to electromagnetic field radiations (EMF-r) for different durations (1h and 4h) and evaluated for mitotic index (MI), phase index, chromosomal aberrations, and DNA damage. DNA damage was investigated with the help of the comet assay by assessing various parameters like % head DNA (HDNA), % tail DNA (TDNA), tail moment (TM), and olive tail moment (OTM). Effects of EMF-r exposure were also compared with that of methyl methanesulfonate (MMS; 90μM), which acted as a positive control. The post-exposure effects of EMF-r after providing the test plants with an acclimatization period of 24h were also evaluated. Compared to the control, a significant increase in the MI and aberration percentage was recorded upon 4h of exposure. However, no specific trend of phase index in response to exposure was detected. EMF-r exposure incited DNA damage with a significant decrease in HDNA accompanied by an increase in TDNA upon exposure of 4h. However, TM and OTM did not change significantly upon exposure as compared to that of control. Analysis of the post-exposure effects of EMF-r did not show any significant change/recovery. Our data, thus, suggest the potential cytotoxic and genotoxic nature of 2100MHz EMF-r. Our study bears great significance in view of the swiftly emergent EMF-r in the surrounding environment and their potential for inciting aberrations at the chromosomal level, thus posing a genetic hazard.

EFECTOS DEL SORBATO DE POTASIO A DIFERENTES CONCENTRACIONES y TIEmPO DE ExPOSICIóN SOBRE EL CICLO CELULAR y EL mATERIAL GENÉTICO EN mERISTEmOS RADICULARES DE AllIuM CEPA l. (CEBOLLA)

EFECTOS DEL SORBATO DE POTASIO A DIFERENTES CONCENTRACIONES y TIEmPO DE ExPOSICIóN SOBRE EL CICLO CELULAR y EL mATERIAL GENÉTICO EN mERISTEmOS RADICULARES DE AllIuM CEPA l. (CEBOLLA) EFFECT OF POTASSIUm SORBATE AT DIFFERENT CONCENTRATIONS AND ExPOSURE TImE ON THE CELL CyCLE AND THE GENETIC mATERIAL IN ROOT mERISTEmS OF AllIuM CEPA l “ONION” Joselyne Quispe, José Saldaña, Tony Verde y Shirley Valderrama Universidad Nacional de Trujillo, Trujillo,Perú DOI: https://doi.org/10.33017/RevECIPeru2010.0011/ RESUMEN Con el propósito de determinar el efecto del Sorbato de Potasio sobre el ciclo celular en meristemos radiculares de Allium cepa L. “cebolla” se establecieron tres grupos experimentales que se expusieron a las soluciones de Sorbato de Potasio en concentraciones de 0.5, 1 y 2 g/L; por 6, 7 y 8 horas cada una y un grupo control. Luego se realizó la respectiva coloración en Orceína acética al 2% de acuerdo a la técnica de Tjio y Levan, observándose con el microscopio compuesto un total de 1500 células meristemáticas en cada uno de los tratamientos. Los resultados aplicando tratamiento después de 8 horas de exposición a la concentración de 2 g/L mostraron una disminución del índice mitótico de 11.26 %, mientras que se incrementó el índice profásico en 95.57 %. Se produjeron también alteraciones como rupturas cromosómicas, puentes anafásicos y células binucleadas. Las pruebas y análisis de varianza, mostraron diferencias significativas entre los diferentes tratamientos, confirmado mediante la prueba de comparación múltiple de promedios de Duncan. Se evidencia un probable efecto genotóxico en el material genético por el Sorbato de Potasio y una alteración en el ciclo celular de los meristemos de A. cepa L.; así mismo, se comprueba la función de biosensor de A. cepa L. en el estudio de sustancias que puedan afectar el ciclo celular. Palabras clave: Allium cepa, Sorbato de Potasio, Índice Mitótico, Alteración del material genético, Puentes anafásicos, Rupturas cromosómicas, Células binucleadas. ABSTRACT In order to determine the effect of Potassium Sorbate on the cell cycle in root meristems of Allium cepa L. “onion” set three experimental groups were exposed to solutions of Potassium Sorbate at concentrations of 0.5, 1 and 2g /l, for 6, 7 and 8 hours each and a control group. Later the respective color in 2% Acetic orcein according to the technique of Tjio and Levan, observed with the compound microscope a total of 1500 meristematic cells in each of the treatments. The appropriate treatment results after 8 hours of exposure to the concentration of 2 g / L showed a decrease in mitotic index of 11.26%, while it increased the rate at 95.57% prophasic index. There were also alterations as chromosome breaks, anaphasic bridges and binucleated cells. The tests and analysis of variance showed significant differences between the different treatments, as confirmed by multiple comparison test of Duncan averages. It shows a probable genotoxic effect in the genetic material by Potassium Sorbate and an alteration in the cell cycle of meristems of A. cepa L., likewise, is found biosensor function of A. cepa L. in the study of substances that may affect the cell cycle. Keywords: Allium cepa, Potassium Sorbate, Mitotic index, Abnormal genetic material, Chromosomal breaks, Anafasic bridges, Binucleated cells.

Exposure to mobile phone radiations at 2350MHz incites cyto- and genotoxic effects in root meristems of Allium cepa.

The exponential increase of electromagnetic field radiations (EMF-r) in the natural environment has raked up the controversies regarding their biological effects. Concern regarding the putative capacity of EMF-r to affect living beings has been growing due to the ongoing elevation in the use of high frequency EMF-r in communication systems, e.g. Mobile phones. In the present study, we tried to examine the cyto- and genotoxic potential of mobile phone EMF-r at 2350MHz using onions (Allium cepa L.). Fresh adventitious onion roots were exposed to continuous EMF-r at 2350MHz for different time periods (1h, 2h and 4h). The evaluation of cytotoxicity was done in terms of mitotic index (MI), phase index and chromosomal aberrations. Genotoxicity was investigated employing comet assay in terms of changes in % HDNA (head DNA) and % TDNA (tail DNA), TM (tail moment) and OTM (olive tail moment). Data were analyzed using one-way ANOVA and mean values were separated using post hoc Tukey's test. The results manifested a significant increase of MI and chromosomal aberrations (%) upon 4h, and ≥ 2h of exposure, respectively, as compared to the control. No specific changes in phase index in response to EMF-r exposure were observed. The % HDNA and % TDNA values exhibited significant changes in contrast to that of control upon 2h and 4h of exposure, respectively. However, TM and OTM did not change significantly. Our results infer that continuous exposures of radiofrequency EMF-r (2350MHz) for long durations have a potential of inciting cyto- and genotoxic effects in onion root meristems.

Protective action of picroliv isolated from Picrorhiza kurroa against radiation clastogenecity on mice and cyclophosphamide-induced cytotoxicity in Allium cepa Root

Objective: Wide-scale cell death, following chemo and radiation therapy, is a major concern in clinical therapy of cancer. The need to identify agents with a potential for chemo and radioprotective potential has assumed great importance. The study aims at the evaluation of the efficacy of picroliv, a potent antioxidant derived from the plant Picrorhiza kurroa, as cyto- and radioprotector. Materials and Methods: Picroliv was fed to mice in a dose of 20 and 30 mg/kg, i.p. daily for 15 days following 4 Gy gamma rays exposure. Body weight, mortality, and hematology were assessed along with endogenous spleen colony-forming unit (CFU) and micronucleus (MN) scoring. In vitro cytoprotective activity was assessed on Allium cepa root meristem growth parameters against cyclophosphamide-induced genotoxicity by determination of mitotic index (MI) and chromosome aberrations (CA). Results: Picroliv treatment resulted in reduced body weight loss, recovery of hematological parameters, increased CFU preservation, and reduced MN expression. Picroliv caused an increase in root length and number of A. cepa simultaneously exposed with cyclophosphamide. Cyclophosphamide-induced cellular damage as measured by MI, and CA was significantly less. Picroliv at 10 mg/ml concentration showed normal dividing cells with few fragments, and sticky chromosome reversing the severe cytotoxicity of cyclophosphamide expressed with chromosome fragmentation, vagrant, sticky, and C-anaphase chromosomes. Conclusion: The results of this study strongly suggest picroliv to be a promising agent for ameliorating injury, following radiation and chemotherapy. The potent antioxidant, hepatoprotective, and immune-modulatory properties of picroliv may be responsible for the apparent cyto- and radioprotective activity.

Genotoxic evaluation of different sizes of iron oxide nanoparticles and ionic form by SMART, Allium and comet assay

In this study, the genotoxic potential of <50 nm, <100 nm iron oxide (Fe2O3) nanoparticles (IONPs) and ionic form were investigated using the wing somatic mutation and recombination test (SMART) and Allium and comet assays. In the SMART assay, different concentrations (1, 2, 5 and 10 mM) of NPs and ionic forms were fed to transheterozygous larvae of Drosophila melanogaster. No significant genotoxic effect was observed in <100 nm NPs and ionic form, while <50 nm IONPs showed genotoxicity at 1 and 10 mM concentrations. Allium cepa root meristems were exposed to five concentrations (0.001, 0.01, 0.1, 1 and 10 mM) of <50 nm and ionic forms for 4 h and three concentrations (2.5, 5 and 10 mM) for <100 nm of IONPs for 24 and 96 h. There was a statistically significant effect at 96 h at all concentrations of <100 nm IONPs. Similarly, <50 nm of IONPs and ionic forms also showed a statistically significant effect on mitotic index frequencies for all concentrations at 4 h. There was a dose-dependent increase in chromosomal abnormalities for IONPs and ionic form. Comet assay results showed time- and concentration-dependent increases in <100 nm NPs. There was a concentration-dependent increase in <50 nm NPs and ionic form ( p < 0.05). Consequently, the <50 nm of Fe2O3 was found toxic compared to 100 nm Fe2O3 and ionic form.

Cytotoxic effect of naphthalene on root meristem of Allium cepa L.

The cytotoxic effect of naphthalene was assessed in the root meristem of Allium cepa L. - a model plant for chromosomal study. The newly emerging roots were treated with 10%, 30%, 50%, 75% and 100% naphthalene solution (v/v). Each treatment was kept for 6, 12, 18, 24 and 48 hours respectively to study their cytotoxic effect. Naphthalene exerted depressive effects on mitosis, including reduced mitotic indices and accumulation of abnormal mitotic phases. The mitotic index showed decreasing tendency with parallel increase in naphthalene concentrations. Sticky metaphase, C- metaphase, diagonal metaphase, nuclear disintegration were found to be in higher frequency in all treatments. Both duration and concentration of the treatment influenced the cell division.

Cytotoxicity of Cheese and Cheddar Cheese food flavorings on Allim cepa L root meristems.

Despite their great importance for the food industry, flavorings, in general, raise a number of questions regarding their cytotoxicity, mutagenicity and carcinogenicity, since, in the literature, there are few studies found evaluating the toxicity on the systemic and cellular level, of these chemical compounds. The root meristems of Allium cepa (onion) are widely used for the assessment of toxicity of chemical compounds of interest. Thus, this study aimed to evaluate, in A. cepa meristematic cells, individually and in combination at the cellular level, the toxicity of synthetic Cheese and Cheddar Cheese food flavorings, identical to the natural, at doses of 1.0 and 2.0 mL, at exposure times of 24 and 48 hours. In combination we used 0.5 mL of Cheese flavor associated with 0.5 mL of Cheddar flavor; and 1.0 mL of Cheese flavor associated with 1.0 mL of Cheddar flavor, at exposure times of 24 and 48 hours. For these evaluations, we used groups of five onion bulbs, which were first embedded in distilled water and then transferred to their respective doses. The root tips were collected and fixed in acetic acid (3:1) for 24 hours. The slides were prepared by crushing and were stained with 2% acetic orcein. Cells were analyzed throughout the cell cycle, totaling 5,000 for each control and exposure time. The mitotic indices calculated and cellular aberrations observed were subjected to statistical analysis using the chi-square test (p <0.05). No chromosomal abnormalities nor those of mitotic spindle were observed for the treatments performed. The results, both individually and in combination, showed that the flavorings under study significantly reduced the cell division rate of the test system cells used. Therefore, under the conditions studied, the two flavorings were cytotoxic.

Evaluation of Cytotoxic Effects of Synthetic Pesticide "Attack" on Root Meristems of &lt;I&gt;Allium cepa&lt;/I&gt; L.

Generally in agriculture farmers use pesticides to increase their yield by reducing crop losses by pests. Some chemical compounds used pesticides are mutagens. Present study evaluated the cytotoxic effect of synthetic pesticide Attack which is used instead of Furadanon root meristems of Allium cepa L. as a test system. The root meristems of A. cepa L. were treated with five concentrations (1%, 2%, 3%, 4% and 5%) of the chemical pesticide Attack for 6 h duration. Exposure to different concentrations of pesticide showed an inhibitory effect on cell division in root tip cells of A. cepa and caused a general decline in Mitotic Index values. Additionally, a wide range of abnormal mitotic stages, were detected in treated cells when compared to control. The total percentage of aberrations generally increased in a dose dependant manner. Among these, frequently observed chromosomal abnormalities were despiralized prophase, disoriented prophase, vagrant prophase, diagonal metaphase, C ‐ metaphase, vagrant metaphase, clumped metaphase, star anaphase, diagonal anaphase, anaphase with two bridges and with multiple bridges, aticky anaphase, telophase stickiness, hyperchromasia, bi‐nucleate and 4 nucleate cells and micronucleus. The results of the present study clearly proved the sensitivity of Allium test and hence substantiate its use as a cytogenetic assay to assess the cytogenetic effect of chemical widely used as pesticides. The cytotoxic pesticides have potential to cause adverse environmental and health effects by inducing chromosomal abnormalities leading to mutations.

Apoptotic induction via membrane/DNA damage and metabolic inactivation by synthetic food colorants in Allium cepa root meristem

The present study investigates the cytotoxic and genotoxic effects of two frequently employed synthetic food colorants, lemon yellow and orange red, using an Allium cepa assay. Uptake of food colorants by root cells at different concentrations and varied exposures significantly altered the cytogenetic system, membrane integrity, mitochondrial function, root growth, and cell division. The food colorants induced significant DNA damage, micronucleus formation, and other severe chromosomal aberrations at genetic level and inhibited cell division as well as root growth. Severe DNA damage, membrane damage, and metabolic inactivation observed in the result are indicative of apoptotic cell death. These results confirm the possible dose-dependent toxicity of these food colorants in plant systems. The chromosomes of plants and animals are morphologically similar and appear to respond towards mutagens in a similar way like mammals, indicating possible damage to the DNA of humans when these colorants are used indiscriminately.

Genotoxic potential of Cynanchum sarcomedium Meve &amp; Liede coupled with its modulatory action on oxidative-stress–mediatedgenotoxicity by hydrogen peroxide

The present study evaluated the genotoxic effect of aqueous extract of C. sarcomedium Meve and Liede and its protective role in chromosomal aberrations induced by 2% hydrogen peroxide (H2O2) on Allium cepa root meristem. Our results showed that the C. sarcomedium extract induced major chromosomal aberrations, viz., nuclear lesions, chromosome breaks, chromosome laggards, vagrance, stickiness, and bridges. These are irreversible in nature and indicate that the plant is a potent clastogen. Total chromosome aberrations were more frequent with increase in exposure time and concentrations of plant extract. For antigenotoxic screening, three different modes of treatment were used: pretreatment, posttreatment, and simultaneous treatment. The significant induction of a wide spectrum of chromosomal aberrations and the reduction in mitotic index effected by the aqueous extract reinforced the genotoxic potential of the plant. The modulatory effect of plant extract was expressed in terms of inhibition percentage and had an excellent effect in reversing chromosomal aberrations induced by H2O2. Dose-dependent results suggest the genotoxic and antigenotoxic effect of C. sarcomedium on onion root tips. These findings offer a useful basis for further investigations on C. sarcomedium, a shrub with a broad array of prospective therapeutic activities.

Genotoxic effects of bilge water on mitotic activity inAllium cepaL.

Bilge water from oceanic vessels is usually discharged through the bilge wells into the Nigerian marine environment indiscriminately as there is no strong indication of compliance with International Maritime Organization (IMO) regulations relating to its exchange and treatment. In this study, the genotoxic effect of bilge water on root meristems of Allium cepa L. was investigated. Exposure of the onion roots to the wastewater at 1, 5, 10, 25 and 50% (v/v; wastewater/tap water) showed strong concentration-dependent root growth inhibition with an EC50 value of 52.6% at 72 h and induced a variety of chromatid and chromosome structural aberrations at 6, 12, 24 and 48 h. The bilge water was effective in the disturbance of the spindle fibre apparatus at all the concentrations used and this was probably due to the heavy metals (Cu, Mn, Pb, Fe, Cd, Cr, Ag, Ni and Zn) present in the wastewater. In comparison with tap water (negative control), the bilge water was also mitodepressive, causing lower mitotic indices. ...

The effect of the edein complex on the activity of apical root meristems of Allium cepa L.

The effect of a mixture of edeins in water solution on the meristematic activity of &lt;em&gt;Allium cepa&lt;/em&gt; L. root tips was studied during the incubation and postincubation periods. Reduction of the elongation growth of the root tips and a strong decrease in. the number of mitoses was observed what, as cytochemical and autoradiographical studies have shown, is due to the inhibition of DNA synthesis. DNA synthesis is completely inhibited after 24 hrs of incubation. Changes caused by 25 ppm concentration of the solution are reversible during postincubation. The concentration of 50 ppm produces irreversible damage. The main direction of cytochemical changes caused by the action of edeins on the meristematic cells is in good accordance with those recorded for bacterial cells (Kuryło-Borowska 1962, Borowski and Chmara 1968).

Investigation of genotoxic potential of various sizes Fe2O3 nanoparticles with comet assay

Event Abstract Back to Event Investigation of genotoxic potential of various sizes Fe2O3 nanoparticles with comet assay İbrahim H. Ciğerci1* and Şöhret Yüksek Kaygisiz1 1 Afyon Kocatepe University, Molecular Biology and Genetics, Türkiye Nanoparticles are found very common in nature. For instance, proteins exist in almost all biological systems and metal-oxide nanoparticles are easily produced etc. Iron oxide nanoparticles with unique magnetic properties have a high potential to use in several biomedical, bioengineering and in vivo applications, including tissue repair, magnetic resonance imaging, immunoassay, drug delivery, detoxification of biologic fluids, cell sorting, and hyperthermia. Although various surface modifications are being done for making these nonbiodegradable nanoparticles more biocompatible . But their toxic potential is still a major concern. Therefore, it is necessary to use further examination assay systems in order to check nanoparticle effects. In this study, genotoxic potential of <50 nm and <100 nm Fe2O3 nanoparticles were investigated by using Comet Assay. Allium cepa root meristems were exposed with five doses (0.001, 0.01, 0.1, 1, 10 mM) of <50 nm for 4 hour and three doses (2.5, 5 (EC50), 10 mM) for <100 nm of Fe2O3 nanoparticle for 24 and 96 h. Methyl methanesulfonate -MMS (10 ppm) was used as a positive control. The results were also analyzed statistically by using SPSS by Windows, 18.0. It was determined that different doses of <50 nm Fe2O3 nanoparticle have no genotoxic effect of DNA. Different doses of <100 nm Fe2O3 have no genotoxic but only 10 mM dose have genotoxic effect on DNA. When compared <50 nm with <100 nm of Fe2O3 nanoparticle; <50 nm have more effects than <100 nm of Fe2O3 on DNA damage. Keywords: Nanoparticles, Fe2O3, Comet Assay, Allium cepa, Genotoxic Conference: ICAW 2015 - 11th International Comet Assay Workshop, Antwerpen, Belgium, 1 Sep - 4 Sep, 2015. Presentation Type: Poster Presentation Topic: Genotoxicity testing of chemicals and nanomaterials Citation: Ciğerci İH and Yüksek Kaygisiz Ş (2015). Investigation of genotoxic potential of various sizes Fe2O3 nanoparticles with comet assay. Front. Genet. Conference Abstract: ICAW 2015 - 11th International Comet Assay Workshop. doi: 10.3389/conf.fgene.2015.01.00017 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Jun 2015; Published Online: 23 Jun 2015. * Correspondence: PhD. İbrahim H Ciğerci, Afyon Kocatepe University, Molecular Biology and Genetics, Afyonkarahisar, Türkiye, cigerci@aku.edu.tr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers İbrahim H Ciğerci Şöhret Yüksek Kaygisiz Google İbrahim H Ciğerci Şöhret Yüksek Kaygisiz Google Scholar İbrahim H Ciğerci Şöhret Yüksek Kaygisiz PubMed İbrahim H Ciğerci Şöhret Yüksek Kaygisiz Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Cytological Effects of Sediment Elutriate from Tambis River System, Barobo,Surigao Del Sur in Allium cepa Root Meristem

The water resources pollution is a worldwide problem. In this manuscript, sediment elutriate (SE) from Tambis River, Barobo, Surigao Del Sur was evaluated for possible cytotoxic effect in actively dividing cells of Allium cepa root meristems. Result shows that at higher concentrations (1000 g/L and500 g/L) can exert mitodepressive effect, Cmitoses as a result of spindle damage, and chromosomal anomalies in actively dividing A. cepa root meristems with P<0.05. This effect was dose dependent and irreversible. Exposure of Allium cepa root to sediment elutriate for 72 hr produced significant atypical changes of chromosomes, sticky metaphases and anaphase bridges. The study suggests that cytotoxic and mutagenic effects of sediment elutriate from Tambis River was significantly higher from negative control (P<0.05).

The biphasic interphase-mitotic polarity of cell nuclei induced under DNA replication stress seems to be correlated with Pin2 localization in root meristems of Allium cepa

Long-term treatment of Allium cepa seedlings with low concentration of hydroxyurea (HU) results in a disruption of cell cycle checkpoints, leading root apex meristem (RAM) cells to an abnormal organization of nuclear structures forming interphase (I) and mitotic (M) domains of chromatin at opposite poles of the nucleus. Thus far, both critical cell length and an uneven distribution of cyclin B-like proteins along the nuclear axis have been recognized as essential factors needed to facilitate the formation of biphasic interphase-mitotic (IM) cells. Two new aspects with respect to their emergence are investigated in this study. The first concerns a relationship between the polarity of increasing chromatin condensation (IM orientation) and the acropetal (base→apex) alignment of RAM cell files. The second problem involves the effects of auxin (IAA), on the frequency of IM cells. We provide evidence that there is an association between the advanced M-poles of the IM cell nuclei and the polarized accumulation sites of auxin efflux carriers (PIN2 proteins) and IAA. Furthermore, our observations reveal exclusion regions for PIN2 proteins in the microtubule-rich structures, such as preprophase bands (PPBs) and phragmoplast. The current and previous studies have prompted us to formulate a hypothetical mechanism linking PIN2-mediated unilateral localization of IAA and the induction of bipolar IM cells in HU-treated RAMs of A. cepa.

Pb-inhibited mitotic activity in onion roots involves DNA damage and disruption of oxidative metabolism.

Plant responses to abiotic stress significantly affect the development of cells, tissues and organs. However, no studies correlating Pb-induced mitotic inhibition and DNA damage and the alterations in redox homeostasis during root division per se were found in the literature. Therefore, an experiment was conducted to evaluate the impact of Pb on mitotic activity and the associated changes in the oxidative metabolism in onion roots. The cytotoxic effect of Pb on cell division was assessed in the root meristems of Allium cepa (onion). The mitotic index (MI) was calculated and chromosomal abnormalities were sought. Pb-treatment induced a dose-dependent decrease in MI in the onion root tips and caused mitotic abnormalities such as distorted metaphase, fragments, sticky chromosomes, laggards, vagrant chromosomes and bridges. Single Cell Gel Electrophoresis was also performed to evaluate Pb induced genotoxicity. It was accompanied by altered oxidative metabolism in the onion root tips suggesting the interference of Pb with the redox homeostasis during cell division. There was a higher accumulation of malondialdehyde, conjugated dienes and hydrogen peroxide, and a significant increase in the activities of superoxide dismutases, ascorbate peroxidases, guaiacol peroxidases and glutathione reductases in Pb-treated onion roots, whereas catalases activity exhibited a decreasing pattern upon Pb exposure. The study concludes that Pb-induced cytotoxicity and genotoxicity in the onion roots is mediated through ROS and is also tightly linked to the cell cycle. The exposure to higher concentrations arrested cell cycle leading to cell death, whereas different repair responses are generated at lower concentrations, thereby allowing the cell to complete the cell cycle.

CYTOGENOTOXICITY EVALUATION OF WATER CONTAMINATED WITH SOME TEXTILE AZO DYES USING RAPD MARKERS AND CHROMOSOMAL ABERRATIONS OF ONION (Allium cepa) ROOT CELLS

The Allium cepa assay is an efficient test for chemical screening and in situ monitoring for genotoxicity of environmental contaminants. This test has been used widely to study genotoxicity of many chemicals pollutions revealing that these compounds can induce chromosomal aberrations in root meristems of Allium cepa. In this study, we aimed to determine genotoxic effects of some textile azo dyes by using the Allium cepa chromosome aberrations test and random amplification of polymorphic DNA (RAPD) analyses. The onion (Allium cepa L.) roots were exposed to different concentrations of three textile azo dyes. The mitotic index of samples exposed to EC50 (500 μg/ml) of selected azo dyes for RLB, RN and SGL was 10.8, 10.3 and 8.8, respectively. The results indicated that the root length of Allium cepa reduced with an increasing azo dye concentration. A random amplification of polymorphic DNA (RAPD) analysis from the extracted DNA was carried out using ten 10-base pair random primers. Ten primers produced 54 bands between 100-1600 base pairs in gel electrophoresis. The number of disappearing bands in profiles was differenced from one to five bands of azo dyes treatment compared to total bands in control and new bands were appeared in treatments. Obtained results from this study revealed that the total chromosomal aberrations and RAPD profiles were performed as useful tool for detection and biomarker assays for the evaluation of genotoxic effects on textile azo dyes polluted plants.

Synthesis of 5-arylidine amino-1,3,4-thiadiazol-2-[(N-substituted benzyol)]sulphonamides endowed with potent antioxidants and anticancer activity induces growth inhibition in HEK293, BT474 and NCI-H226 cells

A series of imines 5-amino-1,3,4-thiadiazol-2-[(N-substituted benzyol)]sulphonamide derivatives were synthesized from various aromatic aldehydes and substituted with benzoyl acetazolamides under different reaction conditions and were evaluated for their antioxidant and free radical scavenging, antimitotic activity by Allium cepa meristem root model and cytotoxicity activity against HEK 293 (human epidermal kidney cell line), BT474 (breast cancer cell line) and NCI-H226 (lung cancer cell line) by MTT assay. Some of the synthesized compounds showed moderately potent cytotoxicity compared to indisulam. Graphical abstractA series of imines 5-amino-1,3,4-thiadiazol-2-[(N-substituted benzyol)]sulphonamide derivatives (9a–j); 5-amino-1,3,4-thiadiazol-2-[N-(substituted benzoyl)]sulphonamide (4a–g); 5-(4-acetamido phenyl sulphonamido)-1,3,4-thiadiazol-2-[N-(substituted benzoyl)]sulphonamide (6a–g); and 5-(4-amino phenyl sulphonamido)-1,3,4-thiadiazol-2-[N-(substituted benzoyl)]sulphonamide (7a–g) were synthesized from acetazolamide and were investigated for the in vitro anticancer by MTT assay, free radical scavenging and antimitotic activity by Allium cepa root meristem model. Experimental observations indicate that synthesized compounds were moderately potent anticancer agents.

Evaluation of antioxidant, antimutagenic, and lipid peroxidation inhibitory activities of selected fractions of Holarrhena floribunda (G. Don) leaves.

Exposure to environmental pollutants often leads to an upsurge in the production of reactive oxygen species (ROS). ROS oxidize cellular fatty acids to produce lipid peroxyl radicals, subsequently transformed into lipid peroxides, which decrease membrane fluidity and increase the activity of various enzymes implicated in degenerative diseases and cancer formation. Edible plants that contain exogenous compounds like curcumeroid, β-carotene, turmeric, and so on, protect the aerobic cells from oxidation of free radicals. This study thus evaluates antioxidant and antimutagenic activities of ethyl acetate, aqueous and methanolic fractions of Holarrhena floribunda leaves. Inhibitory activities of the ethyl acetate fraction on Fe(2+)-induced lipid peroxidation in hen egg yolk; rat liver and brain tissues were also evaluated. The Allium cepa root assay was used to evaluate antimutagenic activity. Results showed that the ethyl acetate scavenged DPPH, OH•, and •O2(-) much stronger than other fractions, as evidenced by its lowest respective IC50 values. All the fractions displayed antimutagenic activities against cyclophosphamide-induced chromosomal aberrations. Likewise, all the fractions induced a reduction in mitotic index, a hallmark of cytotoxicity in the root meristem of Allium cepa. The decrease in mitotic index was most profound for the ethyl acetate fraction, which also demonstrated a significant lipid peroxidation inhibitory activity in the liver and brain homogenates, but not in egg yolk, compared with the ascorbic acid standard. In general, the results suggest that the ethyl acetate fraction might contain beneficial phytochemicals that should be explored as novel candidates for preclinical drug development.