Search Results (72)

Drought is a critical constraint for legume production in semi-arid regions, yet breeding for drought tolerance in faba bean through induced mutagenesis remains largely unexplored. To our knowledge, this is the first EMS-derived mutant population in faba bean specifically developed for drought tolerance, comprising 45 M₂/M₃ lines derived from small-seeded cv. Zina and large-seeded cv. Aguadulce Superlonga), evaluated under two irrigation regimes—100% field capacity (well-watered control) and 40% field capacity (severe stress)—over two consecutive growing seasons in a randomized complete block design with three replications. Drought stress caused severe yield losses, reducing mean seed number per plant by 42.2% and mean seed weight per plant by 47.1%. Analysis of variance revealed highly significant effects of genotype, irrigation, and generation/year on both yield components. The non-significant genotype × irrigation interaction indicated similar proportional drought response across genotypes, while the non-significant three-way interaction suggested relatively consistent genotype rankings across generations/growing seasons. Among the ten drought tolerance indices evaluated, seed-number-based mean productivity (MPn) and stress tolerance index (STIn) were the most discriminating, whereas weight-based indices failed to differentiate genotypes due to the inherent seed-size contrast between botanical backgrounds. Dunnett’s comparisons identified genotype 23 (Zina-derived) as the top performer, significantly exceeding its parent for both MPn and STIn; genotypes 22, 24, 12, 3, and 15 similarly outperformed controls. Cluster analysis broadly distinguished three groups: a tolerant cluster dominated by Zina-derived lines, a moderately tolerant cluster (Zina wild-type), and a sensitive cluster of Aguadulce Superlonga-derived lines. These findings suggest that EMS mutagenesis generated potentially heritable and exploitable variation for drought tolerance, with selected lines representing promising candidates for further multi-environment validation. Full article

Background: Ultraviolet-C (UV-C) radiation is a high-energy physical mutagen capable of inducing DNA damage and oxidative stress, thereby generating genomic variability in photosynthetic organisms. However, its genome-wide effects in unicellular eukaryotic microalgae remain poorly characterized. This study developed a UV-C mutagenesis protocol in Chlamydomonas reinhardtii and evaluated its genomic and physiological impacts. Methods: Axenic cultures of Chlamydomonas reinhardtii (137c+) were exposed to UV-C (100–280 nm) for 12, 48, and 96 min. Viable colonies were analyzed by Random Amplification of Polymorphic DNA PCR (RAPD-PCR) to assess genetic variability, while chlorophyll content and the expression of stress-responsive genes were measured via spectrophotometry and Reverse Transcription quantitative Polymerase Chain Reaction (RT-qPCR), respectively. Results: UV-C treatment induced extensive genomic polymorphism with heterogeneous clustering patterns independent of exposure time, consistent with stochastic mutagenesis. Several mutants exhibited reduced chlorophyll content, indicating impaired photosynthetic efficiency. In contrast, one genotype (pop18) maintained wild-type chlorophyll levels despite marked genetic divergence, coupled with upregulation of antioxidant, DNA repair, and stress-response genes. Conclusions: Overall, UV-C irradiation represents an effective approach to generate non-directional genomic variability in Chlamydomonas reinhardtii, with evidence that random mutagenesis can drive functional reorganization of stress-response pathways, supporting its application in microalgal strain improvement. Full article

Lignocellulose is the most abundant renewable biomass on Earth, and its efficient bioconversion is critical for achieving carbon neutrality, substituting fossil resources, and advancing sustainable biomanufacturing. However, furfural, a dominant inhibitor generated during lignocellulosic pretreatment, severely compromises microbial metabolism and fermentation performance. To date, no systematic review has comprehensively integrated the mechanisms of furfural-induced microbial toxicity with corresponding stress tolerance strategies. This review elaborates on three core themes: the multi-pathway toxic effects of furfural, intrinsic microbial tolerance mechanisms, and advanced strategies for constructing a high-tolerance microbial chassis. Despite considerable progress, several research gaps persist, including poorly understood synergistic or antagonistic interactions between furfural and other hydrolysate inhibitors, insufficient integration of adaptive laboratory evolution, rational design, and random mutagenesis in anti-inhibitor research, and limited understanding of trade-offs between furfural tolerance and industrial fermentation robustness. Future efforts should address these gaps through combinatorial stress simulation, multi-omics profiling, and the “evolve–elucidate–engineer” paradigm, thereby enabling the scalable and stable application of lignocellulosic biomanufacturing. Full article

Background/Objectives: The rapid emergence of antimicrobial resistance (AMR) is driven not only by antibiotic selective pressure but also by bacterial adaptive responses that enhance genetic diversification under stress. The SOS response, regulated by the RecA-LexA axis, plays a central role in coordinating DNA repair, mutagenesis, and phenotypic adaptation. Targeting this pathway represents a promising strategy to limit bacterial adaptability without directly affecting viability. This study aimed to evaluate benzoxaborole-based compounds as potential inhibitors of the LexA regulatory pathway. Methods: A drug repurposing approach was employed to investigate the benzoxaborole scaffold and the clinically approved derivatives tavaborole and crisaborole. Biochemical assays were used to assess LexA autocleavage in a RecA-dependent co-protease system. Molecular docking analyses were performed to evaluate compound binding within the LexA catalytic site. Microbiological assays were conducted to examine the effects on antibiotic-induced filamentation and biofilm formation under different growth conditions. Results: Selected benzoxaboroles inhibited LexA autocleavage, with tavaborole showing the strongest inhibitory profile in the biochemical assay. Docking analyses supported these findings, indicating stable binding within the LexA catalytic site near the catalytic serine residue. At the cellular level, tavaborole and benzoxaborole significantly reduced levofloxacin-induced filamentation at sub-inhibitory concentrations. Both compounds also decreased biofilm formation under nutrient-limited conditions, while no significant effects were observed on preformed biofilms. Crisaborole showed limited cellular activity despite measurable biochemical effects. Conclusions: These findings identify benzoxaboroles as modulators of the LexA-dependent SOS response and support the potential repurposing of clinically approved compounds as adjuvants to limit bacterial adaptive responses associated with antimicrobial resistance. Full article

Soybean (Glycine max L.) is an important agricultural crop for human food and animal feed. Soybean yield is severely constrained by abiotic stresses such as salinity and drought, which affect large proportions of arable and irrigated lands worldwide. This necessitates the development of new soybean varieties tolerant to these stress factors. Mutation breeding is an effective approach to improve the stress tolerance of plants due to increased genetic diversity. In this study, two gamma-induced salinity and drought-tolerant soybean mutants (SM1 and SM3-1) were compared with the parental line S04-05 using GO and KEGG pathway enrichment analyses. GO enrichment analyses revealed extensive differential gene expression in the mutant lines under stress conditions, with significant enrichment of pathways related to photosynthesis, hormone signaling, carbohydrate metabolism, and flavonoid and isoflavonoid biosynthesis. Genotype-specific analyses indicated that the SM3-1 mutant exhibited a dynamic regulatory response associated with maintaining the photosynthetic apparatus and chloroplast homeostasis under stress, whereas the SM1 mutant showed an adaptation strategy based on metabolite-mediated osmotic adjustment and ROS scavenging. Compared to the parental variety S04-05, the mutants showed distinct metabolic regulation in phenylpropanoid/isoflavone metabolism, with upregulation of many isoflavone biosynthesis genes under salinity, drought, and untreated conditions, indicating a key and sustained role of this pathway in stress tolerance. Most SNPs identified in the isoflavone biosynthesis pathway consist of moderate-impact and modifier variations. These findings suggest that gamma mutagenesis and subsequent selection processes allow for the development of novel genetic variants that operate through different physiological and metabolic mechanisms but exhibit similar levels of tolerance. In this respect, the study reveals that mutation breeding is a potentially sustainable and effective breeding strategy for increasing abiotic stress tolerance in soybeans. Full article

Pseudomonas aeruginosa is a major opportunistic pathogen whose adaptive capacity limits the long-term efficacy of antibiotic therapy. Beyond classical resistance mechanisms, antibiotics may also act as stress signals that alter bacterial physiology and evolutionary trajectories. A central element of this response is the SOS regulatory network, controlled by the RecA–LexA system. Although well studied in Escherichia coli, SOS signaling in P. aeruginosa shows distinct regulatory features that remain incompletely understood. This review summarizes experimental and clinical evidence on antibiotic-induced SOS responses in P. aeruginosa, focusing on fluoroquinolones and other genotoxic agents. Fluoroquinolone exposure consistently induces SOS activation and RecA-dependent signaling, affecting short-term antibiotic susceptibility. However, the available evidence does not support a universal role for SOS activation as a major driver of long-term resistance evolution under most tested conditions. Its relationship with antibiotic-induced mutagenesis remains variable: some studies implicate low-fidelity DNA polymerases, whereas others report mutagenesis independent of canonical RecA–LexA control. Beyond mutagenesis, SOS activation may affect integron dynamics, virulence, and biofilm-associated phenotypes. Overall, in P. aeruginosa, the SOS response appears to be a context-dependent modulator of stress adaptation rather than a universal determinant of resistance evolution. Full article

Antimicrobial resistance (AMR) is one of the most pressing global public health challenges, compromising the effectiveness of standard antibiotic therapies and increasing morbidity, mortality, and healthcare costs. The scarcity of new antibiotics has driven research into alternative strategies to restore or enhance the effectiveness of existing drugs. Natural compounds, including polyphenols, alkaloids, terpenes and terpenoids, antimicrobial peptides, and microbial secondary metabolites, exhibit multitarget activities such as membrane disruption, efflux pump inhibition, biofilm suppression, and quorum sensing interference. In parallel, synthetic and semi-synthetic small-molecule inhibitors have been rationally designed to target specific resistance determinants, including β-lactamases, efflux systems, quorum sensing pathways, and stress-induced mutagenesis mechanisms such as the SOS response and DNA repair processes. These agents act as adjuvants, restoring susceptibility or reducing bacterial virulence without exerting strong selective pressure. The integration of natural bioactive compounds and targeted small-molecule inhibitors represents a promising complementary strategy for conventional antibiotics. Further pharmacological and clinical investigations are required to translate these approaches into effective tools within antimicrobial stewardship programs and broader public health strategies aimed at mitigating the global burden of AMR. This narrative review analyses the recent literature on natural compounds and synthetic or semi-synthetic small-molecule inhibitors with documented activity against antimicrobial resistance mechanisms. Full article

This study systematically investigated the genomic alterations in Saccharomyces cerevisiae driven by Replication Factor A (RFA) dosage insufficiency using a promoter-replacement strategy combined with mutation accumulation and whole-genome sequencing. Our findings reveal that transcriptional suppression of RFA2 or RFA3 leads to severe growth inhibition. RFA deficiency induces a distinct mutational spectrum characterized by a high frequency of monosomy and terminal deletions, indicative of severe replication stress. Furthermore, loss of heterozygosity is significantly enriched at centromeres and high-GC regions, underscoring the role of RFA in stabilizing intrinsic genomic barriers. Utilizing an APOBEC3B-induced mutagenesis assay, we demonstrate that RFA insufficiency leads to the extensive accumulation of exposed ssDNA with a distinct bias towards the lagging strand template. Notably, we observed that cells spontaneously inactivate Mismatch Repair (MMR) genes, such as MSH2 and PMS1, to survive RFA-induced stress. This hypermutant phenotype grants a certain degree of growth recovery on Low Galactose (LG) medium. Overall, these findings demonstrate that RFA dosage is a key determinant of genomic integrity and elucidate how repair pathway modulation drives adaptive evolution under replication stress. Full article

DNA is continuously exposed to endogenous and exogenous factors that induce oxidative modifications leading to mutations and genomic instability. Oxidative DNA damage plays a dual role, contributing to physiological signaling at low levels while promoting mutagenesis, carcinogenesis and degenerative diseases when unpaired. Among various lesions, an oxidized base, such as 8-oxo-2′-deoxyguanosine (8-oxodG), is one of the major biomarkers of oxidative stress and genomic damage. Cells have evolved sophisticated repair processes, including base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR), to maintain genomic integrity. Dysregulation or polymorphism of these repair genes has been linked with cancer, neurologic, and cardiovascular disorders. This review discusses an overview of what is presently known concerning oxidative DNA damage and repair mechanisms, particularly emphasizing their molecular players, signaling routes, and human disease implications. It further refers to the latest advances in CRISPR-based technologies and multi-omics approaches that are redefining our understanding of DNA damage response (DDR) networks and creating new frontiers for therapeutic interventions. Full article

Background/Objectives: Induced mutagenesis is vital in genetic enhancement and trait discovery, for genetic analysis and breeding of novel crop varieties with desirable product profiles. Understanding the genetic relationships among newly developed mutant genotypes enables targeted selection and genetic recombination. Therefore, the objective of the current study was to assess the genetic diversity among mutant bread wheat genotypes developed through ethyl methanesulfonate (EMS) mutagenesis using phenotypic traits and diagnostic simple sequence repeat (SSR) markers to identify novel mutants and traits for breeding. Methods: Sixteen advanced (M6) mutant lines, one parental genotype, and three check varieties were genetically profiled using ten diagnostic SSR markers. The genotypes were evaluated for agronomic traits under drought-stressed (DS) and non-stressed (NS) conditions using a 10 × 2 alpha lattice design with two replications. Results: The SSR markers revealed a total of 21 alleles, with an average of 2.10 alleles per locus. An average polymorphic information content (PIC) of 0.51 was computed, revealing moderate informativeness of the genetic markers. Significant (p < 0.05) differences were observed among the test genotypes for key agronomic traits under NS and DS conditions. Grain yield positively and significantly (p < 0.001) correlated with plant height (r = 0.79), number of productive tillers (r = 0.82), root biomass (r = 0.77), shoot biomass (r = 0.74), spike length (r = 0.74), total biomass (r = 0.74), and thousand-seed weight (r = 0.64), under DS conditions. Principal component analysis explained 78.03 and 87.14% genotype variation for assessed agronomic traits under DS and NS conditions, with total biomass, shoot biomass, root biomass, productive tiller, plant height and grain yield as key traits contributing the most variation in the test genotypes. Conclusions: Wheat mutants LMA16, LMA44, and LMA53 were identified as genetically distinct and high yielders under drought stress conditions and recommended for production in rain-fed environments. The selected mutants are a valuable source of genes for wheat improvement programs. Full article

Antibiotic resistance remains one of the most formidable challenges to modern medicine, threatening to outpace therapeutic innovation and undermine decades of clinical progress. While resistance was once viewed narrowly as a clinical phenomenon, it is now understood as the outcome of complex ecological and molecular interactions that span soil, water, agriculture, animals, and humans. Environmental reservoirs act as silent incubators of resistance genes, with horizontal gene transfer and stress-induced mutagenesis fueling their evolution and dissemination. At the molecular level, advances in genomics, structural biology, and systems microbiology have revealed intricate networks involving plasmid-mediated resistance, efflux pump regulation, integron dynamics, and CRISPR-Cas interactions, providing new insights into the adaptability of pathogens. Simultaneously, the environmental dimensions of resistance, from wastewater treatment plants and aquaculture to airborne dissemination, highlight the urgency of adopting a One Health framework. Yet, alongside this growing threat, novel therapeutic avenues are emerging. Innovative β-lactamase inhibitors, bacteriophage-based therapies, engineered lysins, antimicrobial peptides, and CRISPR-driven antimicrobials are redefining what constitutes an “antibiotic” in the twenty-first century. Furthermore, artificial intelligence and machine learning now accelerate drug discovery and resistance prediction, raising the possibility of precision-guided antimicrobial stewardship. This review synthesizes molecular insights, environmental drivers, and therapeutic innovations to present a comprehensive landscape of antibiotic resistance. By bridging ecological microbiology, molecular biology, and translational medicine, it outlines a roadmap for surveillance, prevention, and drug development while emphasizing the need for integrative policies to safeguard global health. Full article

Bacillus subtilis DinG/XPD-like paralogues, DinG and YpvA, have been implicated in overcoming replication stress. DinG possesses a DEDD exonuclease and DNA helicase domains, whereas YpvA lacks the DEDD exonuclease domain. We report that DinG·Mg²⁺ (hereafter referred to as DinG) degrades linear single-stranded (lss) DNA with 3′→5′ polarity and binds lssDNA with higher affinity than its exonuclease-deficient mutant DinG D10A E12A. DinG’s ssDNA-dependent ATPase activity neither stimulates nor inhibits DNA degradation. When bound to the 3′-end of forked DNA, DinG destabilises and degrades the substrate; however, in the presence of ATP, DinG dissociates before reaching the duplex junction. DinG degrades the RNA strand within RNA–DNA hybrids but does not cleave lssRNA unless complexed with Mn²⁺. DinG removes genomic R-loops, as RnhC and PcrA do. DinG physically interacts with RecA and PolA and functions in the same pathway as translesion synthesis (TLS) DNA polymerases (DNAPs) to respond to both spontaneous and methyl methanesulphonate (MMS)-induced mutagenesis. DinG-mGold forms spontaneous foci at or near replication forks, which become enriched following MMS or rifampicin treatment. We propose that DinG contributes to mitigating replication stress by degrading R-loop barriers and facilitating TLS, potentially via RecA-linked mechanisms. Full article

The [2Fe-2S] transcription activator SoxR, a member of the MerR family, functions as a bacterial stress response sensor. The response governed by SoxR is activated by the oxidation of the [2Fe-2S]. In this review, I describe functional differences between Escherichia coli SoxR (EcSoxR) and Pseudomonas aeruginosa SoxR (PaSoxR). Pulse radiolysis demonstrated that the reduced form of EcSoxR reacts directly with O₂⁻ with a second-order rate constant of 5.0 × 10⁸ M⁻¹s⁻¹. PaSoxR was found to undergo a similar reaction, although with a 10-fold smaller rate constant (4.0 × 10⁷ M⁻¹s⁻¹). This difference in rate constants may reflect distinct regulatory features of EcSoxR and PaSoxR. Specifically, mutagenesis studies have shown that Lysine residues―which are located close to [2Fe-2S] clusters, in EcSoxR, but are not conserved in PaSoxR―are essential for EcSoxR activation. In contrast, both EcSoxR and PaSoxR were found to react with various redox-active compounds (RACs), including viologens, phenazines, and quinones, with no apparent differences in the kinetic behavior or specificity of the two proteins. Importantly, both O₂⁻ and RACs oxidize SoxR with the same rate constants. soxR regulon may be induced through multiple pathways, and the activation may depend on the cellular concentration of O₂⁻ and RACs. Full article

Background: Protein kinase R (PKR) inhibits general mRNA translation by phosphorylating the alpha subunit of eukaryotic translation initiation factor 2 (eIF2). PKR also modulates NF-κB signaling during viral infections, but comparative studies of PKR-mediated NF-κB responses across mammalian species and their regulation by viral inhibitors remain largely unexplored. This study aimed to characterize the conserved antiviral and inflammatory roles of mammalian PKR orthologs and investigate their modulation by poxviral inhibitors. Methods: Using reporter gene assays and quantitative RT-PCR, we assessed the impact of 17 mammalian PKR orthologs on general translation inhibition, stress-responsive translation, and NF-κB-dependent induction of target genes. Congenic human and rabbit cell lines infected with a myxoma virus strain lacking PKR inhibitors were used to compare the effects of human and rabbit PKR on viral replication and inflammatory responses. Site-directed mutagenesis was employed to determine key residues responsible for differential sensitivity to the viral inhibitor M156. Results: All 17 mammalian PKR orthologs significantly inhibited general translation, strongly activated stress-responsive ATF4 translation, and robustly induced NF-κB target genes. Inhibition of these responses was specifically mediated by poxviral K3 orthologs that effectively suppressed PKR activation. Comparative analyses showed human and rabbit PKRs similarly inhibited virus replication and induced cytokine transcripts. Amino acid swaps between rabbit PKRs reversed their sensitivity to viral inhibitor M156 and NF-κB activation. Conclusions: Our data show that the tested PKR orthologs exhibit conserved dual antiviral and inflammatory regulatory roles, which can be antagonized by poxviral K3 orthologs that exploit eIF2α mimicry to modulate the PKR-NF-κB axis. Full article

TSGA10, a multifunctional protein critical for mitochondrial coupling and metabolic regulation, plays a paradoxical role in cancer progression and carcinogenesis. Here, we outline a potential mechanism by which TSGA10 mediates metabolism in oncogenesis and thermal modulation. Initially identified in spermatogenesis, TSGA10 interacts with mitochondrial Complex III: it directly binds cytochrome c1 (CytC1). In our model, TSGA10 optimizes electron transport to minimize reactive oxygen species (ROS) and heat production while enhancing Adenosine Triphosphate (ATP) synthesis. In cancer, TSGA10’s expression is context-dependent: Its downregulation in tumors like glioblastoma might disrupt mitochondrial coupling, promoting electron leakage, ROS accumulation, and genomic instability. This dysfunction would be predicted to contribute to a glycolytic shift, facilitating tumor survival under hypoxia. Conversely, TSGA10 overexpression in certain cancers suppresses HIF-1$\alpha$, inhibiting glycolysis and metastasis. TSGA10 and HIF-1$\alpha$ engage in mutual counter-regulation—TSGA10 represses HIF-1$\alpha$ to sustain oxidative phosphorylation (OXPHOS), while HIF-1$\alpha$ suppression of TSGA10 under hypoxia or thermal stress amplifies glycolytic dependency. This interplay is pivotal in tumors adapting to microenvironmental stressors, such as cold-induced mitochondrial uncoupling, which mimics brown adipose tissue thermogenesis to reduce ROS and sustain proliferation. Tissue-specific TSGA10 expression further modulates cancer susceptibility: high levels in the testes and brain may protect against thermal and oxidative damage, whereas low expression in the liver permits HIF-1$\alpha$-driven metabolic plasticity. Altogether, our model suggests that TSGA10 plays a central role in mitochondrial fidelity. We suggest that its crosstalk with oncogenic pathways position it as a metabolic rheostat, whose dysregulation fosters tumorigenesis through ROS-mediated mutagenesis, metabolic reprogramming, and microenvironmental remodeling. Targeting the hypothesized TSGA10-mediated mitochondrial coupling may offer therapeutic potential to disrupt cancer’s adaptive energetics and restore metabolic homeostasis. Full article