Recombination Test Research Articles

Adverse biological effects of ingested polystyrene microplastics using Drosophila melanogaster as a model in vivo organism

ABSTRACT The abundant presence and extensive use of polystyrene microplastics (PSMPs) has recently become a serious environmental concern, as impact of exposure to these substances on human health remains unknown. While in vitro studies yield data on adverse effect of PSMPs, in vivo approaches are more relevant for risk assessment. Drosophila melanogaster is one of the most genetically and experimentally accessible model organisms used in biology as an in vivo model. D. melanogaster was selected as a representative in vivo model organism to examine the genotoxic potential of PSMPs at 5 concentrations of three different sizes namely 4, 10, or 20 µm. In particular, the wing somatic mutation and recombination test (SMART), a scalable, time-efficient in vivo assay developed to study genotoxicity of various compounds in a rapid manner at low costs was used. The third–instar Drosophila larvae were exposed to PSMPs through food at 5 concentrations ranging from 0.01-10 mM. Viability (lethality), larval length, morphological deformations, locomotor activity (climbing behavior), and genotoxic effects were the end-points measured. Exposure to PSMPs at 4, 10, or 20 µm produced significant morphological defects, impaired climbing behavior, and genotoxicity as evidenced by the SMART test demonstrating induction of somatic recombination. Significant increases were observed in the frequency of total spots, suggesting that PSMPs might induce genotoxic activity predominantly via initiation of somatic DNA recombination in a concentration-dependent manner.

Aromatic characterization of traditional Chinese wine Msalais by partial least-square regression analysis based on sensory quantitative descriptive and odor active values, aroma extract dilution analysis, and aroma recombination and omission tests

Msalais is produced from local grape juice in southern Xinjiang (China), by concentration and natural fermentation. In the current study, we combined partial least-square regression analysis based on sensory quantitative descriptive and odor active values (OAVs), aroma extract dilution analysis, and aroma recombination and omission tests to delineate the unique aromatic characteristics of traditional Msalais. Msalais has strong dried fruit, fruit jam, and fruity odors, intermediate-strength caramel and baked odors, and weak floral and herbaceous odors, attributed to 24 key aromatic compounds with OAV ≥1 or flavor dilution ≥4. Furaneol, methionol, and 5-methylfurfural greatly contribute to the dried fruit, fruit jam, and caramel odors, respectively. β-Phenylethyl alcohol mostly contributes to fruit jam odor. β -Damascenone has a complicated effect on dried fruit, fruit jam, and floral odors. Fruity esters contribute to fruity odor. Floral odor is attributed to terpenes. These findings allow precise improvement of the variable quality of traditional Msalais.

Somatic mutations and recombination test in Drosophila melanogaster used for investigating the genotoxicity of some food additives

In the present study, the effects of several food colorings, namely (Ponceau 4R (E 124), Tartrazine (E 102), and Pea green (E 102-E 133), were investigated in vivo using the wing spot test, SMART (somatic mutation and recombination test), in Drosophila melanogaster. Food colorings are the food additives, which are used for improving the appearance of food and beverages. In SMART, multiple wing hair (mwh), flare (flr3), and beaded serrate (BdS) marker genes on the third-largest chromosome of Drosophila are used. The genotoxic effects of the food colorings on the imaginal disc cells that will develop into the wing spot cells during the embryonic development of Drosophila heterozygous larvae and the genotypic changes caused by mutation or recombination in somatic cells also play a role in the formation of mutant spots in the wings. Classes by mutant clones are as follows: small single spots containing 1-2 mwh, large single spots containing ≥3 mwh or ≥4 flr3, and twin spots containing adjacent mwh and flr3 cells (GRAF et al., 1984). Negative control medium was prepared with distilled water, while positive control medium was prepared with 1 mM EMS (ethyl methane sulfonate). According to results obtained from SMART, Ponceau 4R, Tartrazine, and Pea green demonstrated significant results in trans-heterozygous flies (mwh/flr3) for inducing the mutant wing spots compared to control groups at 25 mg/ml, 50 mg/ml, and 75 mg/ml exposure concentrations. On the other hand, Ponceau 4R, Tartrazine, and Pea green yielded significant results for inducing the mutant wing spots in balancer-heterozygous flies (mwh/TM3) at 25 mg/ml, 50 mg/ml, and 75 mg/ml exposure concentrations. The numbers of mutant wing spots were increased by all three colorings depending on the concentration (X2= df=3, P<0.001). It was also determined that these numbers were significantly higher than the flies in the negative control medium and it suggests that these food colorings have genotoxic effects. However, the numbers of mutant wing spot were less than the flies in the positive control medium; this finding indicates that genotoxic effects of the food colorings were not as much as the EMS.

Evaluation of the diagnostic potential of recombinant leptospiral OMP A-like protein (Loa22) and transmembrane (OmpL37) protein in latex agglutination test for serodiagnosis of leptospirosis in animals.

Leptospirosis is a re-emerging zoonotic disease of animals and humans caused by pathogenic Leptospira, which has major public health concerns. The study is aimed to express the recombinant outer membrane protein (OMP) A-like protein (rLoa22) and transmembrane (rOmpL37) protein of Leptospira interrogans serovar Hardjo in the Escherichia coli and their evaluation as a diagnostic antigen in the latex agglutination test (LAT) to detect anti-leptospiral antibodies in the sera of animals. The Loa22 and OmpL37 genes lacking signal peptide coding sequences were individually amplified (522 and 963bp), by polymerase chain reaction, and directionally cloned into a pETite N-His Kan vector for expression. The expressed purified proteins were characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and immunoblot, which confirmed leptospiral specific reactive protein with a molecular weight of ~19 and 36kDa, respectively. The sensitized latex beads coated with these OM proteins separately were evaluated in LAT using cattle sera of microscopic agglutination test (MAT) confirmed positive (n=53) and negative (n=52) cases of leptospirosis. The rLoa22 LAT and rOmpL37 LAT revealed the relative diagnostic sensitivity of 94·34 and 96·23%, diagnostic specificity of 92·31 and 96·15% and accuracy of 93·33 and 96·19%, with the excellent agreement of Cohen's kappa value of 0·87 and 0·92, respectively. After extensive evaluation, this rapid recombinant protein-based field diagnostic test can be applied as a screening test for the detection of anti-leptospiral antibodies in the sera of animals in the field conditions.

Investigation of The Genotoxicity of Ponceau 4R in Drosophila Melanogaster Using the Smart Test and Effects of Some Plants Extracts Against the DNA Damage

In this study, genotoxic effects of Ponceau 4R (E 124) was investigated in vivo using Drosophila melanogaster Meigen in the laboratory experiments. The food coloring in 25‰, 50‰ and 75‰ concentrations were added to food medium of Drosophila during the larval stage and the mutant wing spot numbers were evaluated using the wing spot test, namely SMART (somatic mutation and recombination test). The food colourings are the food additives which are used for increasing the appearance of food and beverages. In SMART, mwh (multiple wing hair), flr3 (flare) and BdS (beader serrate) marker genes on the third largest chromosome of Drosophila are used. Genotoxic effects of the Ponceau 4R in the imaginal disc cells that will develop into the wing spot cells during the embryonic development of Drosophila heterozygous larvae and the genotypic changes caused by mutation or recombination in somatic cells also play a role in the formation of mutant spots in the wings (GRAF et al., 1984). The food coloring which is daily used in our many types of food induced mutant wing spots depend on the concentration in trans-heterozygous flies (mwh/flr3) and in balancer-heterozygous flies (mwh/TM3) in the medium (Chi-Square test; df=3, P<0.001) and the spots were significantly higher than the flies were fed in the medium prepared with distilled water used as negative control showing that the Ponceau 4R has mutagenic effect. However, the mutant spots were less than the flies were fed in the medium prepared with 1 mM EMS (ethyl methane sulfonate) used as positive control showing that mutagenic effect of the colouring was not as much as the EMS. On the other hand, the concentrations of the colouring were used in the mediums together the different plant extracts to determinate whether they have antigenotoxic effects against the colouring. The following plant extracts were added to mediums in 10% concentration with the colouring were: Hypericum perforatum L., (St John’s wort), Silybum marianum (L.) Gaertn. (milk thistle), and Lavandula stoechas L. (topped lavender). The mutant wing spots were compared to control groups showed that the three plant extracts have no effect to reduce the mutant spots in trans-heterozygous flies (mwh/flr3) and in balancer-heterozygous flies and thus have no antigenotoxic effect against the food colouring used experimental treatments (Kruskal-Wallis test; df=2, P>0.05) Keywords: Challenge Genotoxicity, antigenotoxicity, Ponceau 4R, Hypericum perforatum L., Silybum marianum (L.) Gaertn., Lavandula stoechas L., Drosophila melanogaster Meigen, SMART. DOI: 10.7176/JHMN/87-07 Publication date: March 31 st 2021

An Evaluation of the Genotoxic Effects of Electromagnetic Radiation at 900 MHz, 1800 MHz, and 2100 MHz Frequencies with a SMART Assay in Drosophila melanogaster

ABSTRACT With the development of today’s technology, the electromagnetic radiation spread by mobile phones and base stations is also rapidly increasing, and this causes serious concerns about the environment and human health. The Drosophila model organism is widely used in genetic toxicology studies because its genome is highly similar to the genes identified in human diseases. In this study, the genotoxic effects of radiofrequency electromagnetic radiation were evaluated by the wing Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster at 900 MHz, 1800 MHz, and 2100 MHz. The SMART method is based on the observation of genetic changes occurring in the trichomes of the Drosophila wings appearing as mutant clones under the microscope. Throughout the study, total clone parameters were evaluated by exposing the Drosophila larvae to electromagnetic fields for two, four, and six hours per day for two days. As a result of the study, it was observed that the number of mutant clones was statistically increased according to the negative control group in all applications except for the six-hour application at 1800 MHz.

A potential new recombinant echovirus 18 strain detected in a 4-year-old child with encephalitis in China in 2019.

The species Enterovirus B includes diverse serotypes that can cause a wide spectrum of human diseases, such as aseptic encephalitis, myocarditis, and paralysis. In this study, a 4-year-old child was diagnosed with viral encephalitis, but the causative agent could not be identified using routine immunological tests. Using metagenomic RNA sequencing, a novel strain of enterovirus B, strain PC06, was identified, and its genome sequence was determined by RT-PCR and Sanger sequencing. The viral genome sequence was most similar to that of echovirus E18 strain E18-HeB15-54498/HeB/CHN/2015 (GenBank accession MG720261), with 87.73% nucleotide sequence identity, while the viral proteins shared 96.98% amino acid sequence identity with those of E18 strain Jena/AN1365/10 (GenBank accession no. KX139452). Phylogenetic analysis based on the VP1 and 3D genes revealed discrepant placement of PC06 in the two trees. In the 3D tree, PC06 formed a separate branch together with other recombinant E18 strains. Further recombination tests revealed that PC06 had possibly undergone recombination at a site between the structural and non-structural regions during its evolutionary history. Based on the analysis of VP1 phylogeny and using online genotyping tools, this potential recombinant is tentatively considered a strain of echovirus 18. This information might contribute to the diagnosis and prevention of related diseases.

Identification, subtyping, and tracking of dairy spoilage-associated Pseudomonas by sequencing the ileS gene

Pseudomonas spp. are important spoilage bacteria that negatively affect the quality of refrigerated fluid milk and uncultured cheese by generating unwanted odors, flavors, and pigments. They are frequently found in dairy plant environments and enter dairy products predominantly as postpasteurization contaminants. Current subtyping and characterization methods for dairy-associated Pseudomonas are often labor-intensive and expensive or provide limited and possibly unreliable classification information (e.g., to the species level). Our goal was to identify a single-copy gene that could be analyzed in dairy spoilage-associated Pseudomonas for preliminary species-level identification, subtyping, and phenotype prediction. We tested 7 genes previously targeted in a Pseudomonas fluorescens multilocus sequence typing scheme for their individual suitability in this application using a set of 113 Pseudomonas spp. isolates representing the diversity of typical pasteurized milk contamination. For each of the 7 candidate genes, we determined the success rate of PCR and sequencing for these 113 isolates as well as the level of discrimination for species identification and subtyping that the sequence data provided. Using these metrics, we selected a single gene, isoleucyl tRNA synthetase (ileS), which had the most suitable traits for simple and affordable single-gene Pseudomonas characterization. This was based on the number of isolates successfully sequenced for ileS (113/113), the number of unique allelic types assigned (83, compared with 50 for 16S rDNA), nucleotide and sequence diversity measures (e.g., number of unique SNP and Simpson index), and tests for genetic recombination. The discriminatory ability of ileS sequencing was confirmed by separation of 99 additional dairy Pseudomonas spp. isolates, which were indistinguishable by 16S rDNA sequencing, into 28 different ileS allelic types. Further, we used whole-genome sequencing data to demonstrate the similarities in ileS-based phylogenetic clustering to whole-genome-based clustering for 27 closely related dairy-associated Pseudomonas spp. isolates and for 178 Pseudomonas type strains. We also found that dairy-associated Pseudomonas within an ileS cluster typically shared the same proteolytic and lipolytic activities. Use of ileS sequencing provides a promising strategy for affordable initial characterization of Pseudomonas isolates, which will help the dairy industry identify, characterize, and track Pseudomonas in their facilities and products.

Sensitive Immunoassay Detection of Plasmodium Lactate Dehydrogenase by Inductively Coupled Plasma Mass Spectrometry.

Rapid, reliable, and sensitive detection of Plasmodium infection is central to malaria control and elimination. Many Malaria Rapid Diagnostic Tests (RDTs) developed for this purpose depend upon immunoassays that can be improved by advances in bound antibody sensor technology. In a previous study, immuno-polymerase chain reaction (PCR) was shown to provide highly sensitive detection of Plasmodium falciparum lactate dehydrogenase (PfLDH) in monoclonal antibody (mAb) sandwich assays. Here, we show comparably high immunoassay sensitivity by inductively coupled plasma mass spectrometry (ICP-MS) detection of gold nanoparticles (AuNPs). Following capture of PfLDH with the primary mAb and binding of the AuNP-labeled detection mAb, ICP-MS signals from the AuNPs provided quantitative measures of recombinant PfLDH test dilutions and P. falciparum-infected erythrocytes. A detection limit of 1.5 pg/mL was achieved with the PfLDH protein. Parasitemia in cultures of P. falciparum-infected erythrocytes could be detected to a lower limit of 1.6 parasite/μl (p/μl) for early ring-stage forms and 0.3 p/μl for mixed stages including mature trophozoites and schizont-stages. These results show that ICP-MS detection of AuNPs can support highly sensitive and accurate detection of Plasmodium infection.

Chemical composition, genotoxicity and antigenotoxicity study of Artemisia herba-alba using the eye and wing SMART assay of Drosophila melanogaster

The purpose of this study was to determine the chemical composition and to evaluate the genotoxic and antigentoxic activites of the Moroccan Artemisia herba-alba ethanolic extract. The ethanolic extract of Artemisia herba-alba was analyzed by gas chromatography coupled with mass spectroscopy (GC-MS). The mutagenic and antimutagenic activities were evaluated using thesomatic mutation and recombination test (SMART) on Drosophila melanogaster. Methyl methanesulfonate (MMS) was used as the positive control.Twenty-one compounds of the Artemisia herba-alba ethanol extract were identified; the main monoterpenes identified are camphor, α-thujone and β-thujone. Ethanolic extract of Artemisia herba-alba did not show gentotoxicity at doses used in SMART Assays. In the co-treatment, a dose-dependent decrease in mutation frequency was observed for this plant. Ethanolic extract of Artemisia herba-alba at 1.5% demonstrated a marked decrease in MMS with a strong inhibitory effect (80%). The results demonstrate that the Artemisia herba-alba exerted a significant and potent anti-mutagenic activity in wing and eye-spot of D. melanogaster.

Recombinogenic, genotoxic, and cytotoxic effects of azathioprine using in vivo assays

ABSTRACT Azathioprine (Aza) is a purine antimetabolite immunosuppressant that is widely employed for immunosuppressive therapy in post-transplant recipients or patients with autoimmune diseases. Chronic use of immunosuppressants might produce several side effects, including a high rate of neoplasms in these patients. Considering that genotoxic effects are associated with an increased risk of developing cancer, the aim of this study was to examine the recombinogenic, genotoxic, and cytotoxic effects of Aza using Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster, as well as comet and micronucleus assays in mouse bone marrow cells. Further, the adverse effects of Aza were determined in mouse hepatic and renal tissues using histopathological analysis. Data demonstrated that Aza induced significant increased genotoxicity in D. melanogaster and mouse bone marrow cells at all concentrations tested. Homologous recombination was the predominant genotoxic event noted for the first time to be initiated by Aza in SMART. In histopathological analysis, Aza did not show any marked toxic activity in mouse hepatic and renal tissues. Therefore, the high rate of neoplasms reported in patients with long-term use of Aza may be attributed, at least partially, to the genotoxic action of this drug.

Recombinant human thyrotropin stimulation test in 114 dogs with suspected hypothyroidism: a cross-sectional study.

To evaluate the performance and define cut-offs for the interpretation of a thyroid-stimulating hormone (TSH) stimulation test with a recombinant human TSH dose of 75 μg/dog administered intravenously in dogs with suspected hypothyroidism. Cross-sectional study. Medical records of dogs presented for suspected hypothyroidism were retrospectively reviewed. Animals were included if a TSH stimulation test with a recombinant human TSH dose of 75 μg/dog was performed and follow-up was available. Dogs with a post-TSH serum total thyroxine (T4) level of ≥2.2μg/dL were considered euthyroid. Dogs with a post-TSH T4 level of <2.2μg/dL were classified as hypothyroid or euthyroid based on follow-up, including response to levothyroxine supplementation. A receiver operating characteristic curve analysis was used to define the performance of the test. One hundred and fourteen dogs were included. Forty were classified as hypothyroid and 74 as euthyroid. Post-TSH T4 cut-offs of 1.3 and 1.7μg/dL showed sensitivities of 92.5 and 100% and specificities of 97.3 and 93.2%, respectively. Post-TSH T4 levels of >1.7μg/dL had a negative predictive value of 100%. Post-TSH T4 levels of <1.3μg/dL showed a positive predictive value of 94.9%. Area under the ROC curve for post-TSH T4 was 0.99. A TSH stimulation test performed with a recombinant human TSH dose of 75 μg/dog is highly reliable to discriminate between hypothyroid and euthyroid dogs, even in cases of concurrent non-thyroidal illness or administration of medications. A post-stimulation T4 concentration of >1.7μg/dL is suggestive of normal thyroid function.

Molecular epidemiology and phylogenetic analyses of environmental and clinical isolates of Cryptococcus gattii sensu lato in Taiwan.

The rare occurrence of cryptococcosis caused by Cryptococcus gattii sensu lato (C. gattii s.l.) leads to the difficulties in studying the molecular epidemiology of this globally emerging disease. To establish the molecular epidemiological profile of C. gattii s.l. in Taiwan, and understand the genetic relationship between locally endemic and global isolates. A nationwide survey on environmental C. gattii s.l. in Taiwan was conducted from 2017 to 2019. The geographic distribution and molecular epidemiology based on multilocus sequence typing (MLST) data of the environmental isolates were compared with 18 previously collected clinical isolates. Phylogenetic analysis was performed to elucidate the genetic relationship between the global isolates and the isolates endemic to Taiwan. From a total of 622 environmental samples, 104 (16.7%) were positive for C. gattii s.l.. Seven sequence types were identified among the environmental isolates. The genetic population structure showed that the environmental and clinical isolates were closely linked by sequence types and geographical locations. Phylogenetic analysis revealed the association between the C. gattii s.l. isolates in Taiwan and those from South America and South Asia. The recombination test suggested that, in Taiwan, the C. gattii sensu stricto (C. gattii s.s). isolates undergo clonal reproduction and sexual recombination, whereas C. deuterogattii isolates were clonal. The molecular epidemiology of environmental C. gattii s.l. isolates is closely linked to the clinical isolates. Phylogenetic analysis of the environmental isolates provides an insight into the mechanisms underlying reproduction and dispersal of C. gattii s.l. in Taiwan.

Characterization of the key aroma compounds in Yunnan goat milk cake using a sensory-directed flavor analysis.

To identify the key aroma compounds in Yunnan goat milk cake, seven varieties of milk cake samples were subjected to sensory analysis and gas chromatography-mass spectrometry (GC-MS), gas chromatography-olfactometry (GC-O), aroma recombination, omission, and addition tests. The GC-MS results revealed 53 compounds with aroma characteristics in all the samples. A further comparison of odor activity values and aroma intensities (AI) revealed 25 of these compounds as the initial key aroma compounds. The contributions of these key aroma compounds to the sensory attributes were determined using a partial least squares regression. Of these compounds, 2-heptanone and 2-nonanone were closely related to the "milky" and "cheesy" attributes and were highly abundant in the samples from Kunming. Fatty acids, including butanoic acid, hexanoic acid, octanoic acid, and decanoic acid, were the most abundant compounds detected in the milk cakes. These fatty acids were closely related to the "rancid" and "animalic (goat)" attributes and were largely detected in the samples from Dali Dengchuan and Dali Xiaguan. Sensory-directed aroma recombination, omission, and addition tests further validated the important contributions of ethyl butyrate, benzaldehyde, 3-methyl-1-butanol, 2-heptanone, hexanoic acid, and octanoic acid to the overall sensory properties. Moreover, ethyl butyrate, benzaldehyde, and 2-heptanone, when added, had evident inhibitory or masking effects on the AI of "sour," "rancid," and "animalic (goat)" attributes. PRACTICAL APPLICATION: Goat milk cake is a popular acid-curd cheese in Yunnan, China, however, our limited knowledge to its key aroma compounds restricts its development and industrial production. In this study, a sensory-directed flavor analysis was used to characterized the key aroma compounds of Yunnan goat milk cake, which will help to enhance our understanding on the flavor profile of Yunnan goat milk cake and provide a reference for optimizing the flavor feature and organoleptic quality of this fresh goat cheese.

Induration or erythema diameter not less than 5\u2009mm as results of recombinant fusion protein ESAT6-CFP10 skin test for detecting M. tuberculosis infection

BackgroundRecombinant fusion protein ESAT6-CFP10 (EC) is a newly developed skin test reagent for detecting Mycobacterium tuberculosis (M. tuberculosis) infection. In this study, we evaluated whether induration and erythema could be used as diagnostic indicators for EC skin test to detect M. tuberculosis infection.MethodsA total of 743 tuberculosis patients and 1514 healthy volunteers underwent an EC skin test. The diameters of induration and erythema were measured with Vernier caliper, 24 h, 48 h, and 72 h after skin testing. Related indicators of EC reagent diagnostic test were tested, and the diagnostic effects of the four diagnostic indicators for EC skin test were compared.ResultsThe sensitivity of induration / erythema measurement was lower at 24 h after EC skin test than at 48 h or 72 h (P<0.01). There was no difference in consistency (P = 0.16) between induration with clinical diagnosis, and erythema with clinical diagnosis at 48 h (88.88 and 90.16%, Kappa value was 0.75 and 0.78, respectively). In patients, the sensitivity of erythema measurement was higher than induration measurement (P<0.01). In healthy volunteers, the specificity of erythema measurement was lower than induration at 24 h after skin test, but there was no difference at 48 h after skin test (P = 0.22). In BCG vaccination volunteers, the specificity of induration and erythema were higher than 90%. In addition, there was a high consistency of induration and erythema. When induration or erythema was used as a positive diagnostic indicator, the sensitivity of the EC skin test was improved, and was no different from the other three indicators in terms of specificity and consistency with clinical diagnosis.ConclusionsInduration or erythema diameter not less than 5 mm could be used as a diagnostic indicator for detecting M. tuberculosis infection.Trial registrationPhase III clinical trial of recombinant Mycobacterium tuberculosis ESAT6-CFP10 allergen; CTR20150695; registered in December 16, 2015.

Modulating effect of Poincianella bracteosa (Tul.) L.P. Queiroz bark (Leguminosae) on DNA damage induced by doxorubicin on the somatic cells of Drosophila melanogaster wings

The aim of this study was to assess the genotoxic and antigenotoxic effects of Poincianella bracteosa bark aqueous extract on DNA damage induced by doxorubicin (DXR) a chemotherapeutic agent using SMART (Somatic Mutation and Recombination Test). The analysis was performed using the somatic mutation and recombination test in Drosophila melanogaster. Larvae from the standard and high-bioactivity crosses were chronically treated with four concentrations of P. bracteosa bark tea, alone and in association with DXR. The results revealed no mutagenic effect of bark extract for any of the concentrations tested. A modulating effect of aqueous extract in reducing the genotoxic action of DXR was observed for all concentrations tested in descendants of both crosses, but inhibition was more effective in those from the high-bioactive cross. The modulating effect observed may be associated with the presence of tannins and reducing sugars, as observed in phytochemical studies, since they are capable of capturing and stabilizing free radicals. Given the widespread use of P. bracteosa bark in folk medicine, further studies to elucidate the mechanism of action of these cellular compounds and with other experimental models would be useful to confirm that P. bracteosa extract is beneficial to human health.

EVALUATION OF GENOTOXICITY OF THREE FOOD PRESERVATIVES IN DROSOPHILA MELANOGASTER USING SMART AND COMET ASSAYS

The continuously growing food and beverage industry relies on food additives as a main component in their products. Such increased reliance on processed food, lead to neglectance of the harmful effects of the food additives on human health; among these are hypersensitivity, allergic reactions, genotoxicity, mutagenicity and more. This study investigates genotoxic effects of three food preservatives commonly consumed in daily meals; sodium sulphite, boric acid, and benzoic acid using the somatic mutation and recombination test (SMART) and comet assay in Drosophila melanogaster system. All of the tested compounds showed significantly high levels of tumor induction and frequency compared to a negative control in SMART assay. They also showed high amount of DNA damage in the comet assay indicating their high potential of being genotoxic materials.

Modulating effect of vitamin D3 on the mutagenicity and carcinogenicity of doxorubicin in Drosophila melanogaster and in silico studies

Vitamin D3 (VD3) deficiency increases DNA damage, while supplementation may exert a pro-oxidant activity, prevent viral infections and formation of tumors. The aim of this study was to investigate the mutagenicity and carcinogenicity of VD3 alone or in combination with doxorubicin (DXR) using the Somatic Mutation and Recombination Test and the Epithelial Tumor Test, both in Drosophila melanogaster. For better understanding of the molecular interactions of VD3 and receptors, in silico analysis were performed with molecular docking associated with molecular dynamics. Findings revealed that VD3 alone did not increase the frequency of mutant spots, but reduced the frequency of mutant spots when co-administered with DXR. In addition, VD3 did not alter the recombinogenic effect of DXR in both ST and HB crosses. VD3 alone did not increase the total frequency of tumor, but significantly reduced the total frequency of tumor when co-administered with DXR. Molecular modeling and molecular dynamics between calcitriol and Ecdysone Receptor (EcR) showed a stable interaction, indicating the possibility of signal transduction between VD3 and EcR. In conclusion, under these experimental conditions, VD3 has modulatory effects on the mutagenicity and carcinogenicity induced by DXR in somatic cells of D. melanogaster and exhibited satisfactory interactions with the EcR.

Modulating effect of a hydroxychalcone and a novel coumarin–chalcone hybrid against mitomycin-induced genotoxicity in somatic cells of Drosophila melanogaster

Chalcones are aromatic compounds found in plants or obtained by synthetic methods. These compounds and their derivatives have been proven to be responsible for a variety of pharmacological properties, including anti-inflammatory and anticancer activities. A second interesting class of compound are coumarins which comprises a large class of molecules derived from phenolic compounds found mainly in plants, exhibiting multiple biological activities such as antioxidant and anti-tumoral properties. Due to the relevance of these compounds, this study aimed to investigate the genotoxic/antigenotoxic effects of the chalcone (E)-1-(2-hydroxyphenyl)-3-(4-methylphenyl)-prop-2-en-1-one (2HMC) and the coumarin–chalcone hybrid [7-methoxy-3-(E)-3-(3,4,5-trimethoxyphenyl)acryloyl-2H-cromen-2-one] (4-MET) using the somatic mutation and recombination test (SMART) in Drosophila melanogaster. To assess the mutagenic and recombinogenic activities, larvae derived from standard and high bioactivation crosses were treated with different concentrations of 2HMC (10, 50, 100 and 400 µg/mL) or 4-MET (5, 50, 100 and 400 µg/mL) for 48 h. Dimethylsulfoxide (DMSO, 0.5%) was the negative control group. The anti-recombinogenic and antimutagenic activities were assessed using larvae from both crosses co-treated with the same concentrations of 2HMC or 4-MET and mitomycin C (MMC, 0.05 mM). SMART revealed no mutagenic or recombinogenic effects since no significant increase of any category of mutant spots was observed (p > 0.05). However, both compounds reduced the frequency of all spots induced by MMC showing antimutagenic and anti-recombinogenic activities in D. melanogaster cells from both crosses. We suggest that the antimutagenic and anti-recombinogenic activities observed in our study may have been a result of the antioxidant activity of 2HMC and 4-MET.

Assessment of the antioxidant activity and genotoxicity of the extracts and isolated glycosides with a new flavonoid from Lotus aegaeus (Gris.) Boiss

Chemical composition and genotoxic properties of L. aegaeus (Griseb.) Boiss. which is a member of legumes and used as a cover crop, an antimicrobial agent for animal wounds and forage in Central Anatolia were detected for the first time. Nine secondary metabolites together with a new compound for nature were isolated from the n-butanol extract of Lotus aegaeus (Griseb.) Boiss aerial parts. The structures of the isolated compounds were clarified as a known cyanogenic glucoside, linamarin (1), 2 known saponins: wistariasaponin C (8) and wistariasaponin D (9), 5 known flavonoids: quercetin-3-O-β-d-glucopyranoside-7-O-α-l-rhamnopyranoside (2), quercetin-3-O-β-d-galactopyranoside-7-O-α-l-rhamnopyranoside (3), kaempferol-3-O-β-d-galactopyranosyl-7-O-α-l-rhamnopyranoside (4), kaempferol-3-O-β-xylopyranosyl-(1→2)-α--l-rhamnopyranosyl-7-O-α-l-rhamnopyranoside (5), kaempferol 3-O-(5′'-acetyl) apiofuranoside 7-O-rhamnopyranoside(6) and a new flavonoid, kaempferol 3-O-(3′',5′'-diacetyl) apiofuranoside 7-O-rhamnopyranoside (7) by using 1D-2D Nuclear Magnetic Resonance (NMR) and Mass Spectroscopy (MS) methods. Antioxidant effects of the L. aegaeus (Griseb.) Boiss extracts and all isolated compounds were investigated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and superoxide (SO) radical scavenging tests. Quercetin glycosides (2/3) exhibited the strongest antioxidant ability. The genotoxicity of the extracts and some isolated compounds (1,4,6/7,9) were determined in Drosophila melanogaster by the in vivo wing somatic mutation and recombination test (SMART). All genotoxicity test results revealed that L. aegaeus is a reliable source for drug development researches.