Mitotic Aberrations Research Articles

Cyclin-Dependent Kinase-Mediated Phosphorylation of FANCD2 Promotes Mitotic Fidelity.

Fanconi anemia (FA) is a rare genetic disease characterized by increased risk for bone marrow failure and cancer. The FA proteins function together to repair damaged DNA. A central step in the activation of the FA pathway is the monoubiquitination of the FANCD2 and FANCI proteins, which occurs upon exposure to DNA-damaging agents and during the S phase of the cell cycle. The regulatory mechanisms governing S-phase monoubiquitination, in particular, are poorly understood. In this study, we have identified a cyclin-dependent kinase (CDK) regulatory phosphosite (S592) proximal to the site of FANCD2 monoubiquitination. FANCD2 S592 phosphorylation was detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and by immunoblotting with an S592 phospho-specific antibody. Mutation of S592 leads to abrogated monoubiquitination of FANCD2 during the S phase. Furthermore, FA-D2 (FANCD2-/-) patient cells expressing S592 mutants display reduced proliferation under conditions of replication stress and increased mitotic aberrations, including micronuclei and multinucleated cells. Our findings describe a novel cell cycle-specific regulatory mechanism for the FANCD2 protein that promotes mitotic fidelity.

INFLUENCE OF COPPER COMPLEXES [CU(PTA)4 [BF4 ] AND CU(II)2 (3,5-DIPS)4 (H2 O)3 ON THE ORGANISM OF RATS IRRADIATED WITH RADIOISOTOPE TECHNETIUM

One of the priority tasks of modern radiobiology is the search for new, effective radioprotective compounds. In this area, metal-organic complexes with high antioxidant activity are of particular interest. In order to study the possible beneficial radioprotective effect of copper complex compounds [Cu(PTA)4 [BF4 ] and Cu(II)2 (3,5-DIPS)4 (H2 O)3 on an irradiated organism, we studied cytogenetic parameters in 4 groups of experimental animals: intact animals, animals exposed to the radioisotope technetium (Tc) — "pure irradiation", animals with "irradiation + compound [Cu(PTA)4 [BF4 ]", and animals with "irradiation + compound [Cu(II)2 ( 3,5-DIPS)4 (H2 O)3 ". The survival rate and cytogenetic parameters were studied: mitotic index (MI), chromosomal aberrations (CA) and polyploid cells (PC) in the bone marrow cells of the femur. The survival rate in the first and third groups was 100%, in the second group — 40%, and in the fourth — 80%. The dynamics of survival was described by regression curves and equations, which make it possible, using extrapolation, to determine the change in the percentage of survival in the long term of the experiment and to predict the further outcome of the experiment. When analyzing the results in 4 groups of animals, we found a significant difference in cytogenetic parameters between these groups. Thus, for all 3 indicators, a significant difference is observed between intact and irradiated animals, i.e. these parameters can be considered as markers of Tc exposure. In terms of the mitotic index (proliferative activity), a significant difference was found in the irradiated compared with the groups: "irradiation + [Cu(PTA)4 [BF4 ]" and "irradiation + Cu(II)2 (3,5-DIPS)4 (H2 O)3 ", which indicates the radioprotective property of both compounds. By the number of polyploid cells, a significant difference was found between the groups: "pure irradiation" and "irradiation + Cu(II)2 (3,5-DIPS)4 (H2 O)3 ", which also proves the beneficial effect of this compound. Multiregression analysis of cytogenetic parameters along with standard statistical methods confirmed the highest efficiency of [Cu(PTA)4 [BF4] relative to Cu(II)2 (3,5-DIPS)4 (H2 O)3 .

CYTOLOGICAL CHARACTERIZATION OF SOME COWPEA (VIGNA UNGUICULATA L.) ACCESSIONS

Studying the cytological behavior of twenty seven cowpea (Vigna unguiculata L.) accessions to select new promising ones which could be used in cowpea breeding programs were carried out in the present investigation. All tested cowpea accessions exhibited the same normal chromosome number 2n = 22. The means of mitotic index (MI) were significantly different among most of studied accessions and some accessions exhibited high variability in the percentage values of mitotic stages. From all tested cowpea accessions, few of them showed high frequency of total mitotic chromosomal aberrations. Various types of mitotic abnormalities such as; lagging chromosomes, chromosomal bridges, outside chromosome, stickiness and micronuclei have been observed in all tested accessions. The cytological findings revealed that most of tested cowpea accessions had a potential cytological stability with normal chromosomal number 2n=22 and could be considered as good basic tools in cowpea breeding programs.Key wards: Cowpea, Mitotic index, Mitotic aberrations, Plant breeding

In Vivo and In Vitro Study of the Genetic Effects of Cabergoline Drug

This study aimed to stand on genetic effects important of cabergoline drug. This toxic effect was evaluated for three different doses (0.05, 0.1, 0.5 mg/ml) in comparison with control (PBS/ phosphate buffer saline) both in vivo and in vitro. In vivo study involved the cytogenetic evaluation of cabergoline in mice by examination of mitotic index percentage (MI), micronucleus formation (MN) and chromosomal aberrations. Result indicated that all the tested doses cause significant reduction in MI percentage, while significant rise was seen with both MN formation and all studied chromosomal aberrations. While in vitro study involved measuring the effect of cabergoline on normal cell line (REF/ Rat embryonic fibroblast) by studing cell viability through MTT assay and a TP53 codon 72 polymorphism (rs1042522) through (PCR-RFLP). Results recorded that cabergoline caused high proliferation of normal cells at all doses and p53 polymorphism showed that the Arg allele yielding two fragments 213 and 140 bp after cleaving with BstuI,, while the Pro allele had a single 353 bp band because it did not cleaved by BstuI. In conclusion and according to the results care should be taken while obtaining cabergoline as a results of its genetic side effects.

MO049FUNCTIONAL IMPORTANCE OF MAPKBP1 PROTEIN DOMAINS IN NEPHRONOPHTHISIS

Abstract Background and Aims Nephronophthisis is an autosomal-recessive kidney disease that accounts for a significant proportion of end-stage renal disease (ESRD) in childhood, adolescence and early adulthood. Biallelic pathogenic variants in MAPKBP1, encoding the c-Jun N-terminale kinase (JNK)-binding protein 1, are associated with development of Nephronophthisis and subsequent chronic kidney disease (CKD) (Macia et al, AJHG, 2017). We recently characterized MAPKBP1 as microtubule-associated protein that is able to localize to centrioles and the base of primary cilia depending on dimerization via its C-terminal coiled-coil domain (Schönauer et al, Kidney Int, 2020). However, the physiological function of its N-terminal WD40 and intermediate JNK-binding domain is still poorly understood. By in vitro comparison of artificial domain deletions with known and novel patient variants, we aim at pinpointing functional consequences of pathogenic MAPKBP1 in cilia and cell cycle control. Method N-terminally GFP-tagged MAPKBP1 constructs with either full-domain deletions or patient-derived variants were expressed in non-ciliated HeLa and ciliated H69 cells for fluorescence microscopy studies. Furthermore, RNA-seq analysis using primary patient cells was conducted to investigate differentially regulated molecular pathways compared to healthy control individuals. Results Immunofluorescence microscopy revealed inappropriate intracellular localization upon single or combined deletion of any MAPKBP1 protein domain. Compared to wild type, all deletion variants showed reduced intensity at the centrosome and ciliary base. Despite preserved dimerization ability, loss of the intermediate JNK-binding domain (JBD) most effectively abolished centrosomal or ciliary targeting, whereas loss of the N-terminal WD40-domain induced strongest mitotic aberrations. Unlike wild type, both, artificial and patient-derived truncating variants were able to enter the nucleus. RNA-seq analysis using primary patient fibroblasts with varying C-terminal truncations will allow important insights into common gene expression profiles unveiling consequences of aberrant intracellular trafficking. Conclusion In the present work, we demonstrate that all protein domains are indispensable for appropriate MAPKBP1 intracellular localization and function. Most of clinically reported patient variants exhibiting C-terminal truncation of varying lengths resulted in comparable intracellular behavior in presence of an intact N-terminal WD40 domain. Surprisingly, deletion of the JNK-binding domain alone aggravated functional disturbances hinting at a prominent regulatory role of this protein part interdepending with dimerization. Further insights into domain-specific functions will explain molecular disease mechanisms of MAPKBP1.

Assessment of the genotoxicity of sediment elutriates from an aquatic ecosystem on Allium cepa: Limache stream in central Chile.

The aim of this study was to assess the genotoxic effects of sediment elutriates of an aquatic ecosystem. Sediment samples were taken from Limache stream, located in central Chile. The tests were carried out on sediment elutriates. Genotoxicity was determined by bioassay with Allium cepa. The percentage of germination, root growth, mitotic index, and frequency of chromosome aberrations were determined. The results show a significant increase in chromosome aberrations and decrease of the mitotic index in Allium cepa in all the sediment elutriates compared to the control. No significant differences were observed in the percentages of germination or root growth among the sediment elutriates. A negative correlation was found between the mitotic index and chromosomal aberrations. In conclusion, genotoxic variables are more sensitive than growth variables. The sediments contain chemical agents in bioavailable concentrations that produce genotoxic effects. Allium cepa test proved to be a sensitive indicator of genotoxic contaminants in sediment elutriates of the Limache stream in central Chile.

Shaping the BRCAness mutational landscape by alternative double-strand break repair, replication stress and mitotic aberrancies.

Tumours with mutations in the BRCA1/BRCA2 genes have impaired double-stranded DNA break repair, compromised replication fork protection and increased sensitivity to replication blocking agents, a phenotype collectively known as ‘BRCAness’. Tumours with a BRCAness phenotype become dependent on alternative repair pathways that are error-prone and introduce specific patterns of somatic mutations across the genome. The increasing availability of next-generation sequencing data of tumour samples has enabled identification of distinct mutational signatures associated with BRCAness. These signatures reveal that alternative repair pathways, including Polymerase θ-mediated alternative end-joining and RAD52-mediated single strand annealing are active in BRCA1/2-deficient tumours, pointing towards potential therapeutic targets in these tumours. Additionally, insight into the mutations and consequences of unrepaired DNA lesions may also aid in the identification of BRCA-like tumours lacking BRCA1/BRCA2 gene inactivation. This is clinically relevant, as these tumours respond favourably to treatment with DNA-damaging agents, including PARP inhibitors or cisplatin, which have been successfully used to treat patients with BRCA1/2-defective tumours. In this review, we aim to provide insight in the origins of the mutational landscape associated with BRCAness by exploring the molecular biology of alternative DNA repair pathways, which may represent actionable therapeutic targets in in these cells.

Differential sensitivity of Allium cepa L. and Vicia faba L. to aqueous extracts of Cascabela thevetia (L.) Lippold

Cascabela thevetia (L.) Lippold, a well-known plant of family Apocynaceae is used as traditional medicine, has pharmacologically active constituents, yet is highly toxic, due to high glycoside content in seeds, leaves and fruits. So, an assessment of cytotoxicity/mutagenicity becomes prerequisite for its therapeutic efficacy. Two in vivo test systems -Allium cepa test and Vicia faba assay were used for genotoxicity monitoring; with the macroscopic parameter of root growth and the microscopic parameters of Mitotic Index (MI), chromosomal aberrations (CA) and Micronuclei (MN) of meristematic cells as reliable indicators of toxicity. The aqueous leaf and fruit extract of the plant were found to be significantly cytotoxic at 3mg/ml with all sorts of CA. Significant reduction in MI, abundance of CA, presence of MN after recovery, supported by statistical analyses indicated high/ sub lethal genotoxicity. However, the sensitivity of the two systems varied, with A. cepa being more sensitive to reduction in MI and V. faba being more sensitive for CA specially MN. Thus cautious, appropriate and minimum requisite of the plant should be used in therapeutic applications.

Cytogenetic Study on Mitotic Cell Division in Allium cepa by Lead (Pb) and Chromium (Cr) Containing Bacterial Strain Isolated from Tannery Effluents of Bangladesh

In the present study, a bacterial strain capable of Pb and Cr detoxification was isolated from tannery effluents which was identified as Myroides sp. through 16S rRNA gene sequencing. In the cytogenetic experiment, 100 and 600 µg/ml of lead and chromium were used as treatment for the root tips of Allium cepa and caused many chromosomal abnormalities such as abnormal chromosome position, damaged nucleus, breaks of chromosome bridges and fragments also occurred. Notably, sticky metaphase was found where sticky chromosomes indicated highly toxic, usually irreversible consequences leading to cell death. However, Myroides sp. treated supernatant, collected after day 7, used to treat Allium cepa tips showed less mitotic aberrations, nuclear degeneration and observed normal anaphase and telophase stage indicating possible metal detoxifying ability of the isolated strain. Furthermore, LC50 value was 64.63 μl/ml for Myroides sp.

Cytogenetic toxicity from pesticide and trace element mixtures in soils used for conventional and organic crops of Allium cepa L.

Pesticides and trace elements occur in complex mixtures in agroecosystems, affecting soil health and food security. Hence, it is necessary to determine their toxicity in field conditions and to develop monitoring approaches to assess conventional and organic agriculture. The aim of this research was to evaluate the associations between Allium cepa L. cytogenetic biomarkers and the realistic mixture of pesticides and trace elements found in soils of conventional, conversion, and organic crops in an intensive agricultural region in Colombia. Pesticide screening was conducted using GC-MS/MS and LC-MS/MS methods. Arsenic, cadmium, lead, and zinc were analyzed by ICP-MS; chromium, copper, nickel, and selenium by ICP-OES; and mercury by a direct analyzer. The meristematic cells in roots of Allium cepa L. were analyzed through microscopic observations to quantify cytogenetic effects. In conventional crops, 26 pesticides were detected in the soil samples, and those were below the limit of quantification in organic crops. The mean levels of As, Cd, Cr, Ni, Pb, and Se were also greater in soils of conventional crops compared to the organics. In addition, the biomarkers of cytotoxicity and genotoxicity appeared augmented in conventional samples, and those were correlated with pesticide and trace element concentrations, pollution indices, and hazard quotients. Subsequently, a discriminant function based on the mitotic index, chromosomal aberrations, and nuclear abnormalities was suitable to classify the samples by crop type. These results demonstrate the sensitivity of Allium cepa L. to the toxicity of complex mixtures in field crops and its potential as an in-situ approach for soil health monitoring in organic and conventional crop systems.

DNA-PKcs inhibition impairs HDAC6-mediated HSP90 chaperone function on Aurora A and enhances HDACs inhibitor-induced cell killing by increasing mitotic aberrant spindle assembly

ABSTRACT Combining targeted therapeutic agents is an attractive cancer treatment strategy associated with high efficacy and low toxicity. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is an essential factor in DNA damage repair. Studies from us and others have revealed that DNA-PKcs also plays an important role in normal mitosis progression. Histone deacetylase (HDACs) inhibitors commonly lead to mitotic aberration and have been approved for treating various cancers in the clinic. We showed that DNA-PKcs depletion or kinase activity inhibition increases cancer cells’ sensitivity to HDACs inhibitors in vitro and in vivo. DNA-PKcs deficiency significantly enhances HDACs inhibitors (HDACi)-induced mitotic arrest and is followed by apoptotic cell death. Mechanistically, we found that DNA-PKcs binds to HDAC6 and facilitates its acetylase activity. HDACi is more likely to impair HDAC6-induced deacetylation of HSP90 and abrogate HSP90’s chaperone function on Aurora A, a critical mitotic kinase that regulates centrosome separation and mitotic spindle assembly in DNA-PKcs-deficient cells. Our current work indicates crosstalk between DNA-PKcs and HDACs signaling pathways, and highlights that the combined targeting of DNA-PKcs and HDACs can be used in cancer therapy. Abbreviations: DNA-PKcs, DNA-dependent protein kinase catalytic subunit, HDACs, Histone deacetylases, DSBs, DNA double-strand breaks, ATM, ataxia telangiectasia mutated, ATR, ATM-Rad3-related

Chromosomal aberrations induced by cassava industrial effluent using Allium Cepa assay

This study assessed the heavy metal compositions and chromosome aberrations induced by cassava industrial effluent using Allium cepa meristem assay. Effluent collected at the point of discharge from the cassava processing factory located at Lokoja, Kogi State Nigeria was analyzed for quantity of Cadmium (Cd), Chromium (Cr), Copper (Cu), Manganese (Mn), Iron (Fe), Nickel Ni, Cobalt (Co) and Lead (Pb) using Atomic Absorption Spectrophotometer method. Onion (Allium cepa) roots were allowed to grow in beakers containing different concentrations of cassava industrial effluent (i.e. 25%, 50%, 75% and 100%) and the control for 24 hours. Harvesting of the tips for chromosome observations was carried out between 8:00 to 9:00am West Africa Time. Data pooled under X400 magnification of the light microscope for mitotic phases and chromosome aberrations were analyzed using Analysis of Variance (ANOVA) while means with significant difference across concentrations were separated using Duncan Multiple Range Test (DMRT). The results revealed that only Cadmium (Cd) and Lead (Pb) concentrations in the effluent were higher than the minimum values recommended by World Health Organization. The effluent also produce binucleate cells, variant chromosomes, C-mitosis, vacuolated cells, tripolar anaphase and anaphase bridge which suggests the mutagenic and cytotoxic activities of the industrial effluent. The decrease in the Mitotic Indices (MI) of effluent-treated root cells compared to the control indicates mito-depressive ability of the effluent at every concentration. Regular monitoring of industries for compliance to treatment of effluent before releasing them into the environment is recommended.

Evaluation of Cyto-genotoxicity of Perfluorooctane Sulfonate (PFOS) to Allium cepa.

Per- and polyfluoroalkyl substances (PFAS) have emerged as contaminants of global concern. Among several PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are persistent and bioaccumulative compounds. We investigated the cyto-genotoxic potential of PFOS to Allium cepa root meristem cells. The A. cepa root tips were exposed to 6 different concentrations (1-100 mg L-1 ) of PFOS for 48 h. Reduction in mitotic index and chromosomal aberrations was measured as genotoxic endpoints in meristematic root cells. Exposure to PFOS significantly affected cell division by reducing the miotic index at higher concentrations (>10 mg L-1 ). The median effect concentration of PFOS to elicit cytotoxicity based on the mitotic index was 43.2 mg L-1 . Exposure to PFOS significantly increased chromosomal aberrations at concentrations >25 mg L-1 . The common aberrations were micronuclei, vagrant cells, and multipolar anaphase. The alkaline comet assay revealed a genotoxic potential of PFOS with increased tail DNA percentage at concentrations >25 mg L-1 . To our knowledge, this is the first study to report the cyto-genotoxic potential of PFOS in higher plants. Environ Toxicol Chem 2021;40:792-798. © 2020 SETAC.

Protective Effects of Ginger extract against Methotrexate induced cytotoxicity in mice

Ginger (Zingiber officinalis) is one of the frequently used spices in the world and medicinal plant, which has been used all over the world. This study was designed to investigate the role of aqueous ginger extract to inhibit the genotoxicity of methotrexate (MTX) in female albino mice by using these parameters: mitotic index (MI), chromosome aberrations (CA) and micronuclei formation (MNPCE) in somatic cells (bone marrow). The cytological protection of aqueous ginger extract (AGE) was performed at doses (25, 50) mg \\ kg against MTX effects (0.5) mg/kg for three weeks exposure. The results revealed the high inhibitory effects of MTX for cell division in addition to induction of chromosome aberration with micronuclei formation, the absence of cytotoxicity for AGE at tested doses, and the inhibitory efficiency of AGE against the toxicity and mutagenicity of MTX, specially at the dose 50 mg\\kg. From the results we can concluded that the AGE has a promising role in the protection of somatic cells from cytotoxic effects of methotrexate.

Potent aneugenicity of 1-methylpyrene in human cells dependent on metabolic activation by endogenous enzymes.

1-Methylpyrene (1-MP) is a common environmental pollutant and animal carcinogen. After sequential activation by cytochromes P450 and sulfotransferases, it induced gene mutations and micronuclei in mammalian cells. The type of micronuclei formed, entire chromosomes or fragments, was not analysed. In this study, 1-MP and its primary metabolite, 1-hydroxymethylpyrene (1-HMP), were investigated for the induction of centromere-positive and -negative micronuclei in the human hepatoma cell line HepG2 and its derivative C3A, expressing relevant enzymes at higher levels. Under a short-exposure (9h)/long-recovery regime (2 cell cycles in total), 1-MP and 1-HMP provided negative test results in HepG2 cells. However, they induced micronuclei in C3A cells, the effect being blocked by 1-aminobenzotriazole (inhibitor of cytochromes P450s) and reduced by pentachlorophenol (inhibitor of sulfotransferases). Immunofluorescence staining of centromere protein B in the micronuclei revealed purely clastogenic effects under this regime. Unexpectedly, 1-MP and 1-HMP at concentrations 1/5-1/4 of that required for micronuclei formation led to mitotic arrest and spindle aberrations, as detected by immunofluorescence staining of β- and γ-tubulin. Following extended exposure (72h, 2 cell cycles, no recovery), damage to the spindle apparatus and centrosomes was detected at even lower concentrations, with concurrent formation of micronuclei. At low concentrations (1-8µM 1-MP, 0.25-0.5µM 1-HMP), the micronuclei induced were unexceptionally centromere-positive. Thus, the chromosome-damaging mechanism of 1-MP was regime and concentration dependent: potently aneugenic under persistent exposure, while clastogenic at higher concentrations following a short-exposure/long-recovery regime. This is a convincing evidence for the existence of metabolic activation-dependent aneugens.

Overexpression of Cyclin E1 or Cdc25A leads to replication stress, mitotic aberrancies, and increased sensitivity to replication checkpoint inhibitors

Oncogene-induced replication stress, for instance as a result of Cyclin E1 overexpression, causes genomic instability and has been linked to tumorigenesis. To survive high levels of replication stress, tumors depend on pathways to deal with these DNA lesions, which represent a therapeutically actionable vulnerability. We aimed to uncover the consequences of Cyclin E1 or Cdc25A overexpression on replication kinetics, mitotic progression, and the sensitivity to inhibitors of the WEE1 and ATR replication checkpoint kinases. We modeled oncogene-induced replication stress using inducible expression of Cyclin E1 or Cdc25A in non-transformed RPE-1 cells, either in a TP53 wild-type or TP53-mutant background. DNA fiber analysis showed Cyclin E1 or Cdc25A overexpression to slow replication speed. The resulting replication-derived DNA lesions were transmitted into mitosis causing chromosome segregation defects. Single cell sequencing revealed that replication stress and mitotic defects upon Cyclin E1 or Cdc25A overexpression resulted in genomic instability. ATR or WEE1 inhibition exacerbated the mitotic aberrancies induced by Cyclin E1 or Cdc25A overexpression, and caused cytotoxicity. Both these phenotypes were exacerbated upon p53 inactivation. Conversely, downregulation of Cyclin E1 rescued both replication kinetics, as well as sensitivity to ATR and WEE1 inhibitors. Taken together, Cyclin E1 or Cdc25A-induced replication stress leads to mitotic segregation defects and genomic instability. These mitotic defects are exacerbated by inhibition of ATR or WEE1 and therefore point to mitotic catastrophe as an underlying mechanism. Importantly, our data suggest that Cyclin E1 overexpression can be used to select patients for treatment with replication checkpoint inhibitors.

Cytogenetic in Vivo Effects of The Aqueous Extract of Raphanus Sativus L. Leaves in Mitosis of the Meristematic Cells of \Onion Roots

The current study included the preparation of the aqueous extract of Raphanus sativus (Brassicaceae), commonly known as radish which is widely available throughout the world and has been used in folk medicine as a natural drug against many toxicants. The study was designed to evaluate the in vivo cytogenetic activity of the crude aqueous extract of R. sativus on mitosis on Allium cepa root tips as a plant test system. Root tips of A. cepa were tested for four hours with four concentrations of the crude aqueous extract (0.00, 5, 10, 20, 40 mg/ml). The study included a number of cytogenetic analyses such as mitotic index, phase index, and chromosomal aberration. The data showed that this extract led to reducing the mitotic index (MI) to less than 50%. Specifically, when treated with 10 and 40 mg/ml the mitotic index reached 23.72 % and 41.89 %, respectively. This reduction is considered to have toxic and sublethal effects. The extract caused an arrest of the cells at metaphase (c-metaphase) with a high percentage of 80.76% at 5 mg/ml, along with chromosomal aberrations including sticky metaphase, polar deviation, and bridges in anaphase.

Safe natural bio-pigment production by Monascus purpureus using mixed carbon sources with cytotoxicity evaluation on root tips of Allium cepa L.

By increasing the undesirable side effects of synthetic food pigments on human health, using safe natural food pigment become an urgent issue. Incorporate corn starch with oils conducted a high impact on red pigment production by Monascus purpureus. Fortification the medium with sesame oil raised the pigment production by 80% and the dry mass by 63% compared with free oil medium. Response surface methodology maximizes the production with 114.6% (12.8 A500) using medium constituents (g/l); Sesame oil 5; Corn starch 30; Yeast extract 1.5; KH2PO4 2.5 and MgSO4.7H2O 0.1. After evaluating red pigment stability in three common food components, citric acid showed a great effect on residual stability percentage compared with ascorbic and salicylic acid which decrease slightly the residual stability percentage at light and dark conditions. The mitotic index of red pigment was lower than the negative control at all tested concentrations. Different types of mitotic chromosomal abnormalities e.g. lagging chromosome, chromosomal bridge, chromosome and chromatin fragments, outside chromosome, chromosomal stickiness and micro nuclei were recorded. Insignificant increase in total mitotic aberrations percentage in all tested root tips treated with all concentrations of red pigment (1.23, 1.58, 1.63, 2.32 and 2.40%) compared with negative control (0.91%). There was a significant increase in total aberrations percentage after treatment with all concentrations (10, 15, 20 and 25%) of positive control (2.93, 3.00, 3.55 and 6.53 respectively) except (5%) which was insignificant (2.71%). From the previous data, this red pigment can be used as an alternative safe pigment in the food industry.

Evaluation of the genotoxicity of mineral water in polyethylene terephthalate bottles exposed to solar radiation and temperature at variable timescale

AbstractMost bottling companies in Ethiopia use polyethylene terephthalate bottles to package. However, less attention is given to toxic chemicals that could migrate from packaging material into the water. This study aims to assess leaching and toxicological conditions in PET bottled water due to prolonged storage and exposure to direct sunlight. Allium cepa test was used to determine mitotic index (MI) and chromosomal aberrations (CAs). One‐way analysis of variance (ANOVA) and Dunnet’s multiple comparison test were used. P < 0.05 considered statistically significant. The higher chromosomal aberrations and the lowest mitotic index were significantly observed at high temperature (35°C) for one month at P < 0.000. The lower mitotic index was correlated with growth cycle disturbance leading to cell growth reduction. Further investigation is recommended to describe the mechanism and rate of migration of chemicals from water samples supplied in PET bottle.

DHA Affects Microtubule Dynamics Through Reduction of Phospho-TCTP Levels and Enhances the Antiproliferative Effect of T-DM1 in Trastuzumab-Resistant HER2-Positive Breast Cancer Cell Lines.

Trastuzumab emtansine (T-DM1) is an anti-human epidermal growth factor receptor 2 (HER2) antibody-drug conjugated to the microtubule-targeting agent emtansine (DM1). T-DM1 is an effective agent in the treatment of patients with HER2-positive breast cancer whose disease has progressed on the first-line trastuzumab containing chemotherapy. However, both primary and acquired tumour resistance limit its efficacy. Increased levels of the phosphorylated form of Translationally Controlled Tumour Protein (phospho-TCTP) have been shown to be associated with a poor clinical response to trastuzumab therapy in HER2-positive breast cancer. Here we show that phospho-TCTP is essential for correct mitosis in human mammary epithelial cells. Reduction of phospho-TCTP levels by dihydroartemisinin (DHA) causes mitotic aberration and increases microtubule density in the trastuzumab-resistant breast cancer cells HCC1954 and HCC1569. Combinatorial studies show that T-DM1 when combined with DHA is more effective in killing breast cells compared to the effect induced by any single agent. In an orthotopic breast cancer xenograft model (HCC1954), the growth of the tumour cells resumes after having achieved a complete response to T-DM1 treatment. Conversely, DHA and T-DM1 treatment induces a severe and irreversible cytotoxic effect, even after treatment interruption, thus, improving the long-term efficacy of T-DM1. These results suggest that DHA increases the effect of T-DM1 as poison for microtubules and supports the clinical development of the combination of DHA and T-DM1 for the treatment of aggressive HER2-overexpressing breast cancer.