Mutagenic Research Articles

Investigating the effects of colchicine on seed germination and morphological traits in durum wheat (Triticum turgidum subs. durum Desf.)

A broader genetic diversity holds great promise for enhancing the productivity of durum wheat, especially under challenging environmental stressors. Establishing an improved genetic pool through the pre-treatment of durum wheat seeds with antimitotic agents, like colchicine, could play a pivotal role in boosting seed germination, seedling growth, morphological characteristics, and overall yield. This study explored the impact of colchicine on seed germination, growth, and morphological traits in two durum wheat cultivars (PDW-233 and DDW-47). For the experiment, presoaked seeds from each cultivar were exposed to different colchicine concentrations (0.1%, 0.2%, and 0.3%) over an 8-hour period. Quantitative traits such as germination percentage, plant survival rate, plant height, tiller number per plant, seeds per spike, and 1000-grain weight were meticulously measured in the treated plants. The results revealed considerable variability in these quantitative traits across the different colchicine treatments in both wheat varieties in the M1 generation. Significant alterations were observed across various concentrations, indicating colchicine’s potential for inducing genetic diversity within a single generation. These findings underscore the effectiveness of colchicine as a mutagenic agent capable of stimulating notable genetic variation, which, with precise selection, can lead to the identification and development of promising high-yield, stress-tolerant mutants in durum wheat. The results of this study suggest that rigorous selection and further breeding of desirable mutants could result in significantly improved and high-yielding durum wheat lines in subsequent generations. Thus, this approach may offer a viable pathway for enhancing durum wheat’s genetic resilience and productivity.

Genetic and phytochemical evaluation of M2 generation mutants of fenugreek (Trigonella foenum-graecum L.) induced by gamma rays and Ethyl Methane Sulphonate (EMS).

Fenugreek (Trigonella foenum-graecum L.) is highly esteemed for its therapeutic properties and is widely used in traditional medicine and modern pharmacology. Enhancing its genetic traits and phytochemical profile, particularly its trigonelline content, can significantly increase its medicinal and agricultural value. This study aims to investigate the effects of gamma rays and Ethyl Methane Sulphonate (EMS) as mutagenic agents on the genetic and phytochemical characteristics of the M2 generation of fenugreek, focusing on genetic diversity and desirable trait enhancement. To achieve this, various concentrations of EMS and gamma rays were administered to fenugreek seeds, and 27 traits were assessed in the resulting M2 generation. These traits were analyzed for variance, mean values, and correlations. The genetic diversity of 23 M2 offspring was investigated using nine Start Codon Targeted (SCoT) markers. The genetic diversity assessment involved Principal Coordinate Analysis (PCoA) and cluster analysis, utilizing the Dice similarity coefficients and the Unweighted Pair Group Method with Arithmetic Mean (UPGMA). A Bayesian model provided deeper insights into the genetic structure. Results revealed that lower doses of gamma rays (100Gy) and EMS (0.2%) positively impacted specific traits. In comparison, higher doses (200Gy and 0.4% EMS) increased seed trigonelline content to 0.71mg/g dry weight. Among the SCoT markers, SCoT-9 was the most efficient, segregating the populations into three clusters. The first three principal components in the PCoA explained 20% of the total variance, leading to seven subgroup populations distinction. These findings underscore the potential of induced mutagenesis in enhancing desirable traits in fenugreek.

Association of Liver Damage and Quasispecies Maturity in Chronic HCV Patients: The Fate of a Quasispecies.

Viral diversity and disease progression in chronic infections, and particularly how quasispecies structure affects antiviral treatment, remain key unresolved issues. Previous studies show that advanced liver fibrosis in long-term viral infections is linked to higher rates of antiviral treatment failures. Additionally, treatment failure is associated with high quasispecies fitness, which indicates greater viral diversity and adaptability. As a result, resistant variants may emerge, reducing retreatment effectiveness and increasing the chances of viral relapse. Additionally, using a mutagenic agent in monotherapy can accelerate virus evolution towards a flat-like quasispecies structure. This study examines 19 chronic HCV patients who failed direct-acting antiviral (DAA) treatments, using NGS to analyze quasispecies structure in relation to fibrosis as a marker of infection duration. Results show that HCV evolves towards a flat-like quasispecies structure over time, leading also to advanced liver damage (fibrosis F3 and F4/cirrhosis). Based on our findings and previous research, we propose that the flat-like fitness quasispecies structure is the final stage of any quasispecies in chronic infections unless eradicated. The longer the infection persists, the lower the chances of achieving a cure. Interestingly, this finding may also be applicable to other chronic infection and drug resistance in cancer.

Unveiling the genetic basis and metabolic rewiring behind the galactose-positive phenotype in a Streptococcus thermophilus mutant

Streptococcus thermophilus (S. thermophilus) is a widely used starter culture in dairy fermentation, but most strains are galactose-negative and only metabolize glucose from lactose hydrolysis. In this study, we aimed to uncover the mechanisms underlying the acquisition of a stable galactose-positive (Gal+) phenotype in a mutant strain of S. thermophilus IMAU10636. By treating the wild-type strain with the mutagenic agent N-methyl-N-nitro-N-nitrosoguanidine, we successfully isolated a Gal+ mutant, S. thermophilus IMAU10636Y. Comparative enzyme activity assays revealed that the mutant exhibited higher β-galactosidase and galactokinase activities, but lower glucokinase and pyruvate kinase activities compared to the wild-type. High-performance liquid chromatography analysis confirmed the mutant’s enhanced ability to utilize lactose and galactose, leading to increased glucose secretion. Integrated genome and transcriptomics analyses provided deeper insights into the underlying genetic and metabolic mechanisms. We found that the metabolism regulatory network of the glycolysis / Leloir pathway was altered in the mutant, possibly due to the upregulation of the gene expression in the galR-galK intergenic region. This likely led to increased RNA polymerase binding and transcription of the gal operon, ultimately promoting the Gal+ phenotype. Additionally, we identified a mutation in the scrR gene, encoding a LacI family transcriptional repressor, which also contributed to the Gal+ phenotype. These findings offer new perspectives on the metabolic rewiring and regulatory mechanisms that enable S. thermophilus to acquire the ability to metabolize galactose. This knowledge can inform strategies for engineering and selecting Gal+ strains with desirable fermentation characteristics for dairy applications.

Designing and applying a methodology to assess sperm cell viability and DNA damage in a model amphipod

Sperm quality is defined as the sperm cell ability to successfully fertilize eggs and allow normal embryo development⁠. Few studies explore sperm quality using aquatic invertebrates. Parhyale hawaiensis is a marine amphipod with a circumtropical distribution and considered a model for evolution, development, and ecotoxicological studies. We aimed to develop a methodology to collect sperm cells of P. hawaiensis and evaluate their viability and DNA damage (comet assay). We directly exposed the sperm cells to different mutagenic agents to optimize/develop the protocols. Then, as a proof of concept, we exposed the males to mutagenic compounds (EMS, benzo[a]pyrene (BaP), azo and anthraquinone dyes) at non-lethal concentrations verified by the proposed viability test and analyzed their sperm cells for DNA damage (comet assay). Organisms exposed to EMS presented a clear concentration response in the DNA damage response. We also showed that BaP was able to induce a statistically significant increase in DNA damage of the sperm cells. For the two dyes, although DNA damage increased, statistically differences were not observed. We believe we successfully developed a test to detect genotoxicity of chemicals in sperm cells using an invertebrate model. The protocol for sperm cell viability needs to be further explored with different chemicals to verify its utility as a toxicity endpoint. The developed genotoxicity test has the advantages to employ organisms that are easily cultivated in reduced space, use simple laboratory resources and reduced amount of material and reagents. Positive responses with this model could be used to disclose new germ cell mutagen candidates which could be further confirmed in vertebrates' systems.

Comparative analysis of colchicine and bio-catharanthine as mutagenic agents for polyploid generation in wild passion fruit (Passiflora foetida)

Wild type Passiflora foetida or a bush passion fruit is unappealing plant with small fruit size (2-3 cm) to be cultivated as a fruit crop. Plant breeding by polyploidization may improve plant production including increase the fruit size. Many researchers have used colchicine as plant chromosome-modifying agent for polyploidization. However, this potent mutagen is very expensive in developing countries and toxic. Hence, an alternative mutagen needs to be considered, such as the natural bio-catharanthine. This study aims to evaluate the effectiveness of colchicine and bio-catharanthine mutagens in polyploidization of P. foetida plants. Experiment was arranged in split-plot design with three replications. Main plot was combination of the mutagens and concentrations, the subplot was soaking durations. Twenty-five seeds each were soaked for 1-, 2- and 3-days in distilled water as control, colchicine (0.05%, 0.1%, 0.15%) and bio-catharanthine (0.5%, 1% and 1.5%) solutions. Result showed, bio-catharanthine concentration of 1% at immersion durations of 3-days and 1.5% at 1-, 2- and 3-days could only produce 89, 56, 74, and 71% grade 1 mixoploid plants accordingly. On the other hand, colchicine succeeded in obtaining tetraploid plants at concentration of 0.15% with 3-days soaking time even though at lower result (5%). Lower colchicine concentrations with shorter or the same soaking period could only produce 5% grade 2 mixoploid plants. Colchicine with one-tenth lower concentration than bio-catharanthine concentration is still more efficient in inducing polyploidy. Further research by involving bio-catharanthine concentration and varying the soaking time must be pursued to obtain higher-level ploidy.

Small Molecule Drugs Targeting Viral Polymerases.

Small molecules that specifically target viral polymerases-crucial enzymes governing viral genome transcription and replication-play a pivotal role in combating viral infections. Presently, approved polymerase inhibitors cover nine human viruses, spanning both DNA and RNA viruses. This review provides a comprehensive analysis of these licensed drugs, encompassing nucleoside/nucleotide inhibitors (NIs), non-nucleoside inhibitors (NNIs), and mutagenic agents. For each compound, we describe the specific targeted virus and related polymerase enzyme, the mechanism of action, and the relevant bioactivity data. This wealth of information serves as a valuable resource for researchers actively engaged in antiviral drug discovery efforts, offering a complete overview of established strategies as well as insights for shaping the development of next-generation antiviral therapeutics.

In-Host Flat-like Quasispecies: Characterization Methods and Clinical Implications.

The repeated failure to treat patients chronically infected with hepatitis E (HEV) and C (HCV) viruses, despite the absence of resistance-associated substitutions (RAS), particularly in response to prolonged treatments with the mutagenic agents of HEV, suggests that quasispecies structure may play a crucial role beyond single point mutations. Quasispecies structured in a flat-like manner (referred to as flat-like) are considered to possess high average fitness, occupy a significant fraction of the functional genetic space of the virus, and exhibit a high capacity to evade specific or mutagenic treatments. In this paper, we studied HEV and HCV samples using high-depth next-generation sequencing (NGS), with indices scoring the different properties describing flat-like quasispecies. The significance of these indices was demonstrated by comparing the values obtained from these samples with those from acute infections caused by respiratory viruses (betacoronaviruses, enterovirus, respiratory syncytial viruses, and metapneumovirus). Our results revealed that flat-like quasispecies in HEV and HCV chronic infections without RAS are characterized by numerous low-frequency haplotypes with no dominant one. Surprisingly, these low-frequency haplotypes (at the nucleotide level) exhibited a high level of synonymity, resulting in much lower diversity at the phenotypic level. Currently, clinical approaches for managing flat-like quasispecies are lacking. Here, we propose methods to identifying flat-like quasispecies, which represents an essential initial step towards exploring alternative treatment protocols for viruses resistant to conventional therapies.

Fine mapping of major QTL qshgd1 for spontaneous haploid genome doubling in maize (Zea mays L.).

A large-effect QTL was fine mapped, which revealed 79 gene models, with 10 promising candidate genes, along with a novel inversion. In commercial maize breeding, doubled haploid (DH) technology is arguably the most efficient resource for rapidly developing novel, completely homozygous lines. However, the DH strategy, using in vivo haploid induction, currently requires the use of mutagenic agents which can be not only hazardous, but laborious. This study focuses on an alternative approach to develop DH lines-spontaneous haploid genome duplication (SHGD) via naturally restored haploid male fertility (HMF). Inbred lines A427 and Wf9, the former with high HMF and the latter with low HMF, were selected to fine-map a large-effect QTL associated with SHGD-qshgd1. SHGD alleles were derived from A427, with novel haploid recombinant groups having varying levels of the A427 chromosomal region recovered. The chromosomal region of interest is composed of 45 megabases (Mb) of genetic information on chromosome 5. Significant differences between haploid recombinant groups for HMF were identified, signaling the possibility of mapping the QTL more closely. Due to suppression of recombination from the proximity of the centromere, and a newly discovered inversion region, the associated QTL was only confined to a 25 Mb region, within which only a single recombinant was observed among ca. 9,000 BC1 individuals. Nevertheless, 79 gene models were identified within this 25 Mb region. Additionally, 10 promising candidate genes, based on RNA-seq data, are described for future evaluation, while the narrowed down genome region is accessible for straightforward introgression into elite germplasm by BC methods.

Exploring the links between SOS response, mutagenesis, and resistance during the recovery period.

Although the mechanistic connections between SOS-induced mutagenesis and antibiotic resistance are well established, our current understanding of the impact of SOS response levels, recovery durations, and transcription/translation activities on mutagenesis remains relatively limited. In this study, when bacterial cells were exposed to mutagens like ultraviolet light for defined time intervals, a compelling connection between the rate of mutagenesis and the RecA-mediated SOS response levels became evident. Our observations also indicate that mutagenesis primarily occurs during the subsequent recovery phase following the removal of the mutagenic agent. When transcription/translation was inhibited or energy molecules were depleted at the onset of treatment or during the early recovery phase, there was a noticeable decrease in SOS response activation and mutagenesis. However, targeting these processes later in the recovery phase does not have the same effect in reducing mutagenesis, suggesting that the timing of inhibiting transcription/translation or depleting energy molecules is crucial for their efficacy in reducing mutagenesis. Active transcription, translation, and energy availability within the framework of SOS response and DNA repair mechanisms appear to be conserved attributes, supported by their consistent manifestation across diverse conditions, including the use of distinct mutagens such as fluoroquinolones and various bacterial strains.

Abstract 6613: Understanding the causes of head and neck cancer using mutational signature analysis

Abstract The geographical incidence of head and neck cancer (HNC) is heterogeneous, reflecting the prevalence of its main risk factors. Tobacco, either alone or combined with alcohol, is the predominant cause of HNC, while the potential of alcohol as an independent carcinogen is uncertain. Moreover, the etiology remains unknown for ~28% of cases. In this study, we used mutational signature analysis to 1) track the exposure to known and putative risk factors for HNC across multiple geographical regions and subsites, 2) evaluate whether an alcohol signature is present in HNC, and 3) assess its interaction with tobacco or other risk factors. Whole-genome sequencing data was generated from 265 HNC cases from retrospective HNC studies in Europe and South America with available lifestyle and environmental exposure data. Mutational and copy number (CN) signatures were extracted with SigProfilerExtractor and decomposed into COSMIC reference signatures. Associations between the mutational signatures and epidemiological or molecular data were assessed using multivariate regression analysis. The analysis revealed known and previously unreported signatures of endogenous and exogenous exposures. APOBEC-driven signatures (SBS2, SBS13) were identified in 97% (258/265) of cases. We observed differences in tobacco-related mutagenesis across anatomical subsites. While known tobacco signatures (SBS4, SBS92, DBS2, and ID3) were found in larynx cases, the novel signature SBS1536I was enriched in oral cavity cases from ever-smokers, which suggests a site-specific mutagenic effect from different tobacco carcinogens. Furthermore, we demonstrate that signatures associated with alcohol consumption (SBS16, DBS4, and ID11) were enriched in cases exposed to both tobacco and alcohol, indicating an interaction between the two. We also extracted signatures indicative of ultraviolet (UV) light exposure (SBS7a-c, DBS1, and ID13) in cases from the inner lip, tongue, and floor of the mouth, implying a role of UV exposure in oral cavity carcinogenesis. Finally, hierarchical clustering analysis revealed three distinct CN profiles in HNC, each linked to different risk factors and driver mutations: 1) A CN-rich polyploid cluster associated with tobacco smoking and CN signatures of chromosomal instability, including one novel signature (CN48G) enriched in samples from South America, 2) a CN-rich diploid cluster comprising cases related to both tobacco and human papillomavirus infection; and 3) a CN-neutral cluster enriched in samples with unknown etiology. This study uncovers APOBEC signaling, tobacco, alcohol, and potentially UV light exposure, as potent mutagenic agents in HNC. Our findings suggest that the mutational impact of tobacco in HNC is tissue-specific, and that tobacco may enhance the oncogenic effects of alcohol. Finally, the CN profile in HNC is strongly influenced by exposure to risk factors and driver mutations in the tumors. Citation Format: Laura Torrens, Sarah Moody, Carol De Carvalho, Sergey Senkin, Saamin Cheema, Mariya Kazachkova, Valerie Gaborieau, Behnoush Abedi-Ardekani, Ricardo Cortez Cardoso Penha, Joshua Atkins, Priscilia Chopard, Jingwei Wang, Stephen Fitzgerald, Calli Latimer, Christine Carreira, Thomas Cattiaux, Marcos Diaz-Gay, Laura Humphreys, Ludmil B. Alexandrov, Michael R. Stratton, Sandra Perdomo, Paul Brennan, HEADSpAcE consortium. Understanding the causes of head and neck cancer using mutational signature analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6613.

Phytochemical Profile and Evaluation of the Antioxidant, Cyto-Genotoxic, and Antigenotoxic Potential of Salvia verticillata Hydromethanolic Extract.

This study comprises the phytochemical characterization, the evaluation of the total phenolic content (TPC) and antioxidant activity (AA), and the investigation of the cyto-genotoxic and antigenotoxic potential of hydromethanolic extract derived from Salvia verticillata L. leaves. HPLC-DAD-ESI-MS and HPLC-DAD were used for the characterization of the extract and determination of the major ingredients. Afterwards, the TPC and AA were determined. The cytotoxic and genotoxic effect of the extract on cultured human lymphocytes at concentrations of 10, 25, and 50 μg mL-1 was investigated via the Cytokinesis Block MicroNucleus (CBMN) assay. Moreover, its antigenotoxic potential against the mutagenic agent mitomycin C (MMC) was assessed using the same assay. The hydromethanolic extract comprises numerous metabolites, with rosmarinic acid being the major compound. It had a high value of TPC and exerted significant AA as shown by the results of the Ferric Reducing Antioxidant Power (FRAP) and Radical Scavenging Activity by DPPH• assays. A dose-dependent cytotoxic potential was recorded, with the highest dose (50 μg mL-1) exhibiting statistically significant cytotoxicity. None of the tested concentrations induced significant micronuclei (MN) frequencies, indicating a lack of genotoxicity. All tested concentrations reduced the MMC-mediated genotoxic effects, with the two lowest showing statistically significant antigenotoxic potential.

Systematic assessment on the remediation of Bisphenol A in the global environments: a mixed method analysis of research outputs

Bisphenol A (BPA) is an endocrine-disrupting compound and a mutagenic agent that poses health hazards to living organisms, making it a global contaminant. Several remediation techniques have been reported in the literature, however, a mixed-method science mapping analysis of research trends on BPA is still lacking. The present study aimed to investigate global research trends in BPA remediation. Published research papers on BPA remediation indexed in Web of Science, PubMed, and Scopus between 1992 and 2021 were analysed qualitatively and quantitatively using science mapping algorithms including Rstudio, bibliometrix package and R Version 4.2.1. The thematic areas were determined using k-means clustering of the author-keywords while Porter’s stemming algorithm was used to stemmed inflectional terms to their roots. Overall, 640 documents were published by 1903 authors with 2.07 authors/article and 0.336 article/author, 4.31 co-authors/article, an annual growth rate of 17.35% and a collaboration index of 2.99. Research productivity increased from 1 article in 1992 to 93 articles in 2021. The citations of the topmost 23 articles ranged from 365 to 109 and the total citation per year ranged from 45.6 to 27.3. China (n = 267, 41.7%), Japan (n = 53, 8.3%), USA (n = 33, 5.2%) and Korea (n = 28, 4.4%) were respectively the top four countries based on the total of published articles and overall citation. There were 48 relevant keywords dominated by Bisphenol A, adsorption, biodegradation, and peroximonosulphate. The present analysis identifies research accomplishment, focus and gaps on Bisphenol A remediation and offer the researchers the information needed to forecast future research priorities that can help policymakers and governments to internationalize collaborations and create research curricula that can remediate BPA on a global scale.

Response surface methodology for optimization of biodiesel production by the Penicillium commune NRC 2016 and its mutants

AbstractWith increasing energy requirements and limited fuel resources, finding cheap renewable sources is essential. The objective of our current economic study is to enhance biodiesel production from the Penicillium commune, NRC 2016. Four mutagenic agents were used to improve the lipid production from P. commune NRC 2016: gamma radiation, ethyl methanesulfonate (EMS), ethidium bromide (Et Br), and sodium azide (NaN3). The Inter-Simple-Simplece Repeats molecular (ISSR) marker was used to compare the wild type of P. commune NRC 2016 and the resulting mutants. The results showed a major difference between the wild type and its mutants. Response surface methodology was used to optimize the culture conditions for lipid production by P. commune NRC 2016, and the induced mutants used hydrolysate that was produced from bagasse using Bacillus cereus 3SME. The maximum lipid content (g/l) for P. commune NRC 2016, P. commune NRC 2016–1, P. commune NRC 2016–2, and P. commune NRC 2016–3 were 2.01, 2.55, 1.71, and 2.27, respectively. Gas chromatographic analysis was used for biodiesel produced from P. commune NRC 2016 wild type, and its mutants were mainly C16–C18, which is suitable for transesterification. The physical properties, such as density, viscosity, cloud point, pour point, and cetane number, of the biodiesel from P. commune NRC 2016 and its mutants were similar to those of standard biodiesel and could be applied on a large scale. The biodiesels produced through P. commune NRC 2016 and its mutants can be utilized on a broad scale as eco-friendly products obtained from a low-cost carbon source.

Genotoxic effects and mitosis aberrations of chromium (VI) on root cells of Vicia faba and its molecular docking analysis

Like other heavy metals, Cr (VI) is a powerful carcinogen and mutagen agent. Its toxic effects on plants are well considered. In order to elucidate its adverse effects, the present work aims to study the mitosis aberrations of Cr (VI) on the Vicia faba root-cells and its molecular docking analysis to understand the genotoxicity mechanisms. In-vivo, Vicia faba plants were exposed to 50 and 100 μM Cr (VI) for 48 h. In-silico, molecular docking and molecular dynamics simulation were used to study the interactions between dichromate and tubulin tyrosine ligase T2R-TTL (PDBID: 5XIW) with reference to Colchicine (microtubule inhibitor). According to our results, Cr (VI) affects growth and cell division and also induces many mitosis aberrations such as chromosome sticking, anaphase/telophase bridges, lagging chromosomes and fragmentation during all phases of mitosis. On the one hand, Cr (VI) reduces mitotic index and promotes micronuclei induction. The in-silico results showed that dichromate establishes very strong bonds at the binding site of the tubulin tyrosine ligase T2R-TTL, with a binding affinity of −5.17 Kcal/Mol and an inhibition constant of 163.59 μM. These interactions are similar to those of colchicine with this protein, so dichromate could be a very potent inhibitor of this protein's activity. TTL plays a fundamental role in the tyrosination/detyrosination of tubulin, which is crucial to the regulation of the microtubule cytoskeleton. Its inhibition leads to the appearance of many morphogenic abnormalities such as mitosis aberrations. In conclusion, our data confirm the highest genotoxicity effects of Cr (VI) on Vicia faba root-cells.

CORRELATION COEFFICIENT AND REGRESSION ANALYSIS OF SOME ECONOMIC TRAITS IN GARDEN PEAS AFFECTED BY CHEMICAL AND PHYSICAL MUTAGENS

Garden pea (Pisum sativum L.) is one of the most vegetable legume crops grown in Egypt through the winter season. In order to develop high-yieldinggenotypes in this legume crop available genetic wealth is very essential. Therefore, genetic variability induced by mutagenic agents in plant growth traits and their contribution towards seed yield may be used as a criterion for yield improvement in garden peas. The overall objective of this study was to estimate the extent of association between plant growth traits with the doses of mutagenic agents through correlation and regression analysis. One germplasm of garden pea, as well as seven doses of mutagenic agents in addition to the control, were used in this study. The experiment was carried out in a randomized complete block design with three replications in the Agri-Farm of Genetic Department inside the campus of Mansoura University. Analysis of the correlation coefficient revealed that the amount of correlation coefficients appeared very close between plant fresh weight, chlorophyll b with the mutagenic doses. Meanwhile, plant dry weight, leaf area developed per plant andtotal chlorophyll concentration exhibited a positive correlation with mutagenic doses that induced new genotypes in garden peas. Therefore, these traits may be considered the most reliable traits that respond to mutagenic agents which can be used as indicators for new genotypes induced which related to effective improvement in the growth and yield of garden peas through mutation breeding.

The Organotypic Culture of Mouse Seminiferous Tubules as a Reliable Methodology for the Study of Meiosis In Vitro.

Male mouse meiosis has been traditionally studied using descriptive methods like histological sections and spreading or squashing techniques, which allow the observation of fixed meiocytes in either wildtype or genetically modified mice. For these studies, the sacrifice of the males and the extraction of the testicles are required to obtain the material of study. Other functional in vivo studies include the administration of intravenous or intraperitoneal drugs, or the exposure to mutagenic agents or generators of DNA damage, in order to study their impact on meiosis progression. However, in these studies, the exposure times or drug concentration are important limitations to consider when acknowledging animal welfare. Recently, several approaches have been proposed to offer alternative methodologies that allow the in vitro study of spermatocytes with a considerable reduction in the use of animals. Here we revisit and validate an optimal technique of organotypic culture of fragments of seminiferous tubules for meiotic studies. This technique is a trustable methodology to develop functional studies that preserve the histological configuration of the seminiferous tubule, aim homogeneity of the procedures (the use of the same animal for different study conditions), and allow procedures that would compromise the animal welfare. Therefore, this methodology is highly recommendable for the study of meiosis and spermatogenesis, while it supports the principle of 3R's for animal research.

Mutagenic activity of water samples from Kaskelen River (Kazakhstan) on plant test systems

Rivers are pivotal in the life processes of all living organisms, including humans. The engagement of rivers in daily human economic endeavours has precipitated and continues to precipitate disturbances in the ecological equilibrium, long-established by the forces of evolution. Consequently, providing clean, high-quality water is paramount for sustaining all life forms. This investigation aimed to examine the mutagenic potential of water samples from the Kaskelen River, which is subjected to anthropogenic influences, employing plant-based test subjects. The water’s mutagenic properties were assessed through an assay for chromosomal aberrations (utilizing the metaphase approach) on Hordeum vulgare L. The results demonstrated a statistically significant decline in the mitotic index under all experimental conditions compared to the negative control (p<0.05), indicating the cytotoxic effects of the water samples under study. Further analysis of the water’s mutagenic activity elucidated its capacity to induce structural mutations within the root meristem cells of barley, manifesting a significant uptick in the frequency of chromosomal aberrations relative to the negative control (p<0.05). The extensive array of observed chromosomal rearrangements underscores the existence of mutagenic agents in the river’s water, possessing a broad spectrum of effects.

WINTER WHEAT MUTATION VARIABILITY UNDER LOW-DAMAGE ABILITY MUTAGEN ACTION

The purpose of our study was to show the possibilities of a chemical supermutagen in the regular induction of certain types of mutations. Winter wheat dry seeds of eight varieties were acted with water (control) and DAB (1.4-bisdiazoacetylbutane) action in concentrations of 0.1%, 0.1%, 0.3%. Studies have shown that the use of this mutagen is expedient from the point of view of obtaining valuable forms of low-growing, earlyripening, late-ripening, high-yielding lines, forms with high productive tillering. The mutagen by its nature has a rather low affinity, at least for this group of genotypes, however, this factor still affects the frequency of some types of mutations. Even extreme concentrations of this mutagenic agent did not lead to a significant decrease in the number of mutations; however, they reached a maximum in the spectrum of possible changes. Further studies are needed on changes in photosynthetic activity and associated persistence.

In-Host HEV Quasispecies Evolution Shows the Limits of Mutagenic Antiviral Treatments.

Here, we report the in-host hepatitis E virus (HEV) quasispecies evolution in a chronically infected patient who was treated with three different regimens of ribavirin (RBV) for nearly 6 years. Sequential plasma samples were collected at different time points and subjected to RNA extraction and deep sequencing using the MiSeq Illumina platforms. Specifically, we RT-PCR amplified a single amplicon from the core region located in the open-reading frame 2 (ORF2). At the nucleotide level (genotype), our analysis showed an increase in the number of rare haplotypes and a drastic reduction in the frequency of the master (most represented) sequence during the period when the virus was found to be insensitive to RBV treatment. Contrarily, at the amino acid level (phenotype), our study revealed conservation of the amino acids, which is represented by a high prevalence of the master sequence. Our findings suggest that using mutagenic antivirals concomitant with high viral loads can lead to the selection and proliferation of a rich set of synonymous haplotypes that express the same phenotype. This can also lead to the selection and proliferation of conservative substitutions that express fitness-enhanced phenotypes. These results have important clinical implications, as they suggest that using mutagenic agents as a monotherapy treatment regimen in the absence of sufficiently effective viral inhibitors can result in diversification and proliferation of a highly diverse quasispecies resistant to further treatment. Therefore, such approaches should be avoided whenever possible.