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AbstractPeptaibols are fungal peptides that exhibit efficacy against pathogen microorganisms. Trichokonin VI (TK-VI) and trichokonin VIII (TK-VIII) are known peptaibols isolated from the endolichenic fungi Hypocrea sp. Previous investigations reported that trichokonin VI presents antiproliferative effects on tumor cells. This study is pioneering in elucidating the genotoxic effects of TK-VI and TK-VIII, contributing to the thorough assessment of their safety as potential therapeutic agents. The present investigation aimed to evaluate the genotoxicity of TK-VI and TK-VIII on CHO-K1 cells. Cytotoxicity was evaluated using the XTT assay and clonogenic survival assays, followed by evaluation of DNA damage using the comet assay and micronucleus test conducted in vitro. The XTT assay results indicated IC50 values of 10.30 µM and 9.89 µM for TK-VI and TK-VIII, respectively. The clonogenic survival assay indicated that concentrations of 10 µM or higher completely inhibited the cell colony formation. In the comet assay, both TK-VI and TK-VIII increased the DNA damage score and the frequency of comet nuclei in all tested concentrations. In the micronucleus assay, TK-VI and TK-VIII at 10 µM increased the frequency of MN in CHO-K1 cells. Both TK-VI and TK-VIII exhibited genotoxic effects. Our findings underscore the importance of considering the genotoxicological safety of peptaibols, particularly when assessing their potential for other biological activities. [ABSTRACT FROM AUTHOR]

The nucleolar localization of proteins is regulated by specific signals directing their trafficking to nucleus and nucleolus. Here, we elucidate the mechanism underlying the nuclear and nucleolar localization of the nucleomethylin (NML) protein, focusing on its nuclear localization signals (NLSs) and nucleolar localization signal (NoLS). Using a combination of bioinformatic analysis and experimental validation, we identified two monopartite and one bipartite NLS motifs within NML. The combined presence of both monopartite NLSs significantly enhances nuclear localization of the protein, while specific basic amino acid clusters within the bipartite NLS are crucial for their functionality. We also reveal the functional role of the NLS‐coupled NoLS motif in driving nucleolar localization of NML, which contains an arginine‐rich motif essential for its function. The basic residues of the arginine‐rich motif of NoLS of NML interacts with nucleophosmin 1 (NPM1), allowing the possible liquid‐liquid phase separation and retention of NML in the nucleolus. Remarkably, the strong NoLS of NML can direct the nucleolar localization of a cytosolic protein, aldolase, emphasizing its potency. Overall, our findings provide insights into the combinatorial functioning of NLSs and NoLS in regulating the subcellular localization of NML, highlighting the intricate regulatory mechanisms governing its localization within the nucleus and nucleolus. [ABSTRACT FROM AUTHOR]

The transition of chromatin configuration in mammalian oocytes from a non‐surrounded nucleolus (NSN) to a surrounded nucleolus (SN) is critical for acquiring the developmental competence. However, the genomic and epigenomic features underlying this process remain poorly understood. In the present study, we first establish the chromatin accessibility landscape of mouse oocytes from NSN to SN stage. Through the integrative analysis of multi‐omics, we find that the establishment of DNA methylation in oocytes is independent of the dynamics of chromatin accessibility. In contrast, histone H3K4me3 status is closely associated with the dynamics of accessible regions during configuration transition. Furthermore, by focusing on the actively transcribed genes in NSN and SN oocytes, we discover that chromatin accessibility coupled with histone methylation (H3K4me3 and H3K27me3) participates in the transcriptional control during phase transition. In sum, our data provide a comprehensive resource for probing configuration transition in oocytes, and offer insights into the mechanisms determining chromatin dynamics and oocyte quality. [ABSTRACT FROM AUTHOR]

The aviation sector is believed to be responsible for considerable environmental damage attributed to emission of a large number and amount of pollutants. Airports are often surrounded by forest fragments and humid areas that attract birds of prey and hence may potentially serve as useful bioindicators. The aim of the present study was to examine genotoxic potential in raptors exposed to airport pollution using the micronucleus (MN) test and morphological changes as evidenced by bilateral symmetry. This investigation was conducted at Salgado Filho International Airport of Porto Alegre – RS as well as in private and zoological breeding grounds. The presence of metals was measured in the blood cells of the collected birds. Seventeen birds (Caracara (Polyborus) plancus) were used in this study 11 from exposed and 6 from non-exposed group. The nuclear alterations clearly indicate that organisms exposed to airport pollution exhibited a significantly higher frequency of genetic damage compared to non-exposed birds. Further, manganese and chromium were detected exclusively in the blood of the exposed group. In contrast, the analysis of bilateral symmetry did not detect any significant morphologic differences between the two groups. Therefore, data indicate that blood genotoxic stress occurs in birds of prey living in civil aviation areas as evidenced by MN frequency increase and presence of manganese and chromium. [ABSTRACT FROM AUTHOR]

Anthracene (Anth) and pyrene (Pyr), two of the priority polycyclic aromatic hydrocarbons (PAHs), being lipophilic in nature, not only accumulate in animals, but also settle in the sediment of water bodies leading to continuous exposure for animals. Anth and Pyr when exposed to sunlight can be photoactivated and have harmful effects on aquatic organisms. A comparative analysis was carried out to assess the acute, sub-chronic, genetic and biochemical toxicity of Anth and Pyr in F. limnocharis tadpoles following short exposures to sunlight on a daily basis. In the bioaccumulation studies, it was found that both Anth and Pyr accumulated in the tadpole tissues in a concentration and time dependent manner. The LC50 values for Anth (under 15 min of daily sunlight exposure) were found to be 2.87, 2.59, 2.28, 1.80 mg/L at 24, 48, 72 and 96 h of the exposures. The corresponding LC50 values for Pyr were 1.03, 0.80, 0.62, 0.42 mg/L. Sublethal exposure of Anth and Pyr affected the survivality, time to metamorphosis as well as morphometric parameters under sunlight exposure. In the genotoxicity assessment studies, particularly the micronucleus test and comet assay, it was found that Pyr led to a higher incidence of micronucleus formation and DNA damage in comparison to Anth. The exposure to PAHs resulted in significant changes in the activity of antioxidant-mediated protective response, specifically the SOD activity, which varied between the groups treated with Anth and Pyr. On the other hand, Pyr treated group showed a higher level of GSH as compared to Anth treated groups. Moreover, the elevation in MDA level in the Anth and Pyr treated groups suggests an increase in lipid peroxidation. Future research should focus on understanding the ecotoxicological risk faced by anuran amphibia due to PAHs that frequently occur in aquatic environments and developing strategies to mitigate these risks. [ABSTRACT FROM AUTHOR]

The nucleolus, a recognized biomolecular condensate, serves as the hub for ribosome biogenesis within the cell nucleus. Its quantity and morphology are discernible indicators of cellular functional states. However, precise identification and quantification of nucleoli remain challenging without specific labeling, particularly for suspended cells, tissue-level analysis and high-throughput applications. Here we introduce a single-cell laser emitting cytometry (SLEC) for label-free nucleolus differentiation through light-matter interactions within a Fabry–Perot resonator. The separated gain medium enhances the threshold difference by 36-fold between nucleolus and its surroundings, enabling selective laser emissions at nucleolar area while maintaining lower-order mode. The laser emission image provides insights into structural inhomogeneity, temporal fluid-like dynamics, and pathological application. Lasing spectral fingerprint depicts the quantity and size of nucleoli within a single cell, showcasing the label-free flow cytometry for nucleolus. This approach holds promise for nucleolus-guided cell screening and drug evaluation, advancing the study of diseases such as cancer and neurodegenerative disorders. Monitoring the biology of nucleoli remains challenging, particularly in the case of suspended cells and in high-throughput applications. Here, the authors report single-cell laser emitting cytometry, which can profile nucleoli in single cells and tissues in a label-free manner. [ABSTRACT FROM AUTHOR]

Background: Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer commonly used in a wide variety of products, including medical devices. It is rapidly metabolized in the liver into various metabolites upon absorption through oral ingestion, dermal absorption, and inhalation. DEHP is classified as a non-genotoxic hepatocarcinogen in rodents, as its chronic exposure has been associated with the development of liver cancer in these animals, but most genotoxicity studies have been negative. Epidemiologic studies in humans suggest that long-term high intakes of DEHP may be a risk factor for liver dysfunction. The repeated-dose liver micronucleus (RDLMN) assay is a well-established method for assessing chromosomal changes caused by hepatic genotoxins and/or carcinogens. It is particularly valuable for detecting substances that undergo metabolic activation, especially when the metabolite has a short half-life or does not reach the bone marrow effectively. Therefore, we investigated whether the RDLMN assay could detect DEHP-induced micronucleus formation in the liver following a 14 or 28-day treatment. Results: We report that the RDLMN assay demonstrated an increased frequency of hepatic micronuclei in rats exposed to DEHP for 14 or 28 days. The increases in micronuclei correlated with hepatomegaly, an established response to phthalates in the liver. Conversely, no such increases were observed in the micronucleus assay using bone marrow from these rats. Conclusion: The detection of DEHP-induced micronuclei by the RDLMN assay suggests that this assay could detect the potential genotoxicity and hepatocarcinogenicity of DEHP. It also demonstrated the utility of the RDLMN assay in identifying metabolically activated hepatic carcinogens. [ABSTRACT FROM AUTHOR]

Neuromelanin-pigmented neurons of the substantia nigra are selectively lost during the progression of Parkinson's disease. These neurons accumulate iron in the disease state, and iron-mediated neuron damage is implicated in cell death. Animal models of Parkinson's have evidenced iron loading inside the nucleoli of nigral neurons, however the nature of intranuclear iron deposition in the melanised neurons of the human substantia nigra is not understood. Here, scanning transmission x-ray microscopy (STXM) is used to probe iron foci in relation to the surrounding ultrastructure in melanised neurons of human substantia nigra from a confirmed Parkinson's case. In addition to the expected neuromelanin-bound iron, iron deposits are also associated with the edge of the cell nucleolus. Speciation analysis confirms these deposits to be ferric (Fe3+) iron. The function of intranuclear iron in these cells remains unresolved, although both damaging and protective mechanisms are considered. This finding shows that STXM is a powerful label-free tool for the in situ, nanoscale chemical characterisation of both organic and inorganic intracellular components. Future applications are likely to shed new light on incompletely understood biochemical mechanisms, such as metal dysregulation and morphological changes to cell nucleoli, that are important in understanding the pathogenesis of Parkinson's. Showcasing the application of scanning transmission x-ray microscopy to study the oxidation state of intranuclear iron in nigral neurons. Implications and potential future applications are discussed. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs), including carbon quantum dots, graphene quantum dots, carbon nanodots, and polymer dots, have gained significant attention due to their unique structural and fluorescence characteristics. This review provides a comprehensive overview of the classification, structural characteristics, and fluorescence properties of CDs, followed by an exploration of various fluorescence sensing mechanisms and their applications in gene detection, nucleolus imaging, and gene delivery. Furthermore, the functionalization of CDs with diverse surface ligand molecules, including dye molecules, nucleic acid probes, and metal derivatives, for sensitive nucleic acid detection is systematically examined. Fluorescence imaging of the cell nucleolus plays a vital role in examining intracellular processes and the dynamics of subcellular structures. By analyzing the mechanism of fluorescence and structure–function relationships inherent in CDs, the nucleolus targeting abilities of CDs in various cell lines have been discussed. Additionally, challenges such as the insufficient organelle specificity of CDs and the inconsistent mechanisms underlying nucleolus targeting have also been highlighted. The unique physical and chemical properties of CDs, particularly their strong affinity toward deoxyribonucleic acid (DNA), have spurred interest in gene delivery applications. The use of nuclear-targeting peptides, polymers, and ligands in conjunction with CDs for improved gene delivery applications have been systematically reviewed. Through a comprehensive analysis, the review aims to contribute to a deeper understanding of the potential and challenges associated with CDs in biomedical applications. [ABSTRACT FROM AUTHOR]

Pathogens need to manipulate plant functions to facilitate the invasion of their hosts. They do this by secreting a cocktail of molecules called effectors. Studies of these molecules have mostly focused on the mechanisms underlying their recognition and the subsequent transcriptional reprogramming of cells, particularly in the case of R gene-dependent resistance. However, the roles of these effectors are complex, as they target all cell compartments and their plant targets remain largely uncharacterized. An understanding of the mechanisms involved would be a considerable asset for plant breeding. The nucleolus is the site of many key cellular functions, such as ribosome biogenesis, cellular stress regulation and many other functions that could be targets for pathogenicity. However, little attention has been paid to effectors targeting nucleolar functions. In this review, we aim to fill this gap by providing recent findings on pathogen effectors that target and manipulate nucleolar functions and dynamics to promote infection. In particular, we look at how some effectors hijack ribosome biogenesis, the modulation of transcription or alternative splicing, all key functions occurring at least partially in the nucleolus. By shedding light on the role of the plant nucleolus in pathogen interactions, this review highlights the importance of understanding nucleolar biology in the context of plant immunity and the mechanisms manipulated by plant pathogens. [ABSTRACT FROM AUTHOR]

Nucleoli are fundamentally essential sites for ribosome biogenesis in cells and formed by liquid-liquid phase separation (LLPS) for a multilayer condensate structure. How the nucleoli integrity is maintained remains poorly understood. Here, we reveal that METTL3/METTL14, the typical methyltransferase complex catalyzing N6-methyladnosine (m6A) on mRNAs maintain nucleoli integrity in human embryonic stem cells (hESCs). METTL3/METTL14 deficiency impairs nucleoli and leads to the complete loss of self-renewal in hESCs. We further show that SUV39H1/H2 protein, the methyltransferases catalyzing H3K9me3 were dramatically elevated in METTL3/METTL14 deficient cells, which causes an accumulation and infiltration of H3K9me3 across the whole nucleolus and impairs the LLPS. Mechanistically, METTL3/METTL14 complex serves as an essential adapter for CRL4 E3 ubiquitin ligase targeting SUV39H1/H2 for polyubiquitination and proteasomal degradation and therefore prevents H3K9me3 accumulation in nucleoli. Together, these findings uncover a previously unknown role of METTL3/METTL14 to maintain nucleoli integrity by facilitating SUV39H1/H2 degradation in human cells. Nucleoli are essential cellular sites for ribosome biogenesis that are formed by liquid-liquid phase separation. Here the authors show that METTL3/METTL14 maintain nucleoli integrity through mediating SUV39H1/2 degradation in human embryonic stem cells. [ABSTRACT FROM AUTHOR]

Heat stress (HS) impacts the nuclear proteome and, subsequently, protein activities in different nuclear compartments. In Arabidopsis thaliana, a short exposure to 37 °C leads to loss of the standard tripartite architecture of the nucleolus, the most prominent nuclear substructure, and, consequently, affects the assembly of ribosomes. Here, we report a quantitative label-free LC‒MS/MS (Liquid Chromatography coupled to tandem Mass Spectrometry) analysis to determine the nuclear proteome of Arabidopsis at 22 °C, HS (37 °C for 4 and 24 h), and a recovery phase. This analysis identified ten distinct groups of proteins based on relative abundance changes in the nucleus before, during and after HS: Early, Late, Transient, Early Persistent, Late Persistent, Recovery, Early-Like, Late-Like, Transient-Like and Continuous Groups (EG, LG, TG, EPG, LPG, RG, ELG, LLG, TLG and CG, respectively). Interestingly, the RNA polymerase I subunit NRPA3 and other main nucleolar proteins, including NUCLEOLIN 1 and FIBRILLARIN 1 and 2, were detected in RG and CG, suggesting that plants require increased nucleolar activity and likely ribosome assembly to restore protein synthesis after HS. [ABSTRACT FROM AUTHOR]

Batch spawner fishes develop successive clutches of oocytes which allows them to participate in many reproductive cycles during their adult life (iteroparous) and spawn in multiple events within each breeding cycle. Here, ovarian follicular development was morpho‐functionally analyzed in females of the iteroparous batch spawner fish Gymnocorymbus ternetzi. To obtain better insights into the reproductive morpho‐physiology in batch spawners, the objective of this research was to analyze the dynamics of the follicular development, with its hormonal regulation between two active reproduction events. We found that over 16 days, follicles progressed asynchronously to chromatin nucleolus, Primary and Secondary growth stages of oogenesis with progressive secretion of 17β‐estradiol (E2). During the end of secondary growth, the increase in 17α,20β‐dihydroxy‐4‐pregnen‐3‐one (17,20β‐p) was measured relative to the maturation process of the ovarian follicles (e.g., nuclear migration and its rupture during the resumption of meiosis). Interestingly, an additional increase in E2 was observed after fish reproduction, probably related to the recruitment of new batch follicles for secondary growth. We also measured the high values of multiple condition factor post‐reproduction measurements, reflecting more energy invested during the pre‐reproductive process. We also quantified high concentrations of 17,20β‐p, probably related to the recruitment of a new batch of oogonia to meiosis, presumably secreted by post‐ovulatory follicles, after fish reproduction. We finally found that fish without exposure to reproductive stimulus developed a regression phase at day 24, characterized by massive follicle atresia, that allow them to recycle energy and constitutive materials of the follicles invested during oogenesis for another reproductive cycle. [ABSTRACT FROM AUTHOR]

Nucleoli form interchromosomal contacts with genes controlling differentiation and carcinogenesis. DUX4 genes specify transcription factor possessing two homeodomains. Previously, using Circular Chromosome Conformation Capture (4С) approach on population of cells, it was demonstrated that DUX4 gene clusters form frequent contacts with nucleoli. It was found also that these contacts are almost completely abolished after heat shock treatment. 4C approach as all ligation-mediated methods is capable to detect rather close interactions between chromatin loops in nuclei. In order to independently confirm the formation and the frequency of the contacts in single cells we used FISH approach. Here, we show that DUX genes in single cells form stable contacts in all tested HEK293T cells. During heat shock, DUX4 genes reversibly move 1–3 µm away from the nuclei. We conclude that interchromosomal contacts formed by nucleoli are strong, dynamic, and reversible, providing both the initiation and maintenance of a differentiated state. [ABSTRACT FROM AUTHOR]

To investigate the morphological features of keratic precipitates (KPs) with in vivo confocal microscopy (IVCM) in vitreoretinal lymphoma (VRL). Patients with biopsy-proven VRL were reviewed, and 12 patients (16 eyes) with KPs examined by IVCM were included. Five distinct KP morphologies on IVCM were observed: dendritic, nibbling, linear, globular, and stippled. Dendritic KPs were discovered in 9 eyes (56.3%), with a hyperreflective core and multiple thin pseudopodia. Nibbling KPs were found in 8 eyes (50.0%), featuring irregularly hyperreflective borders and a mottled reflective interior. Linear, stippled, and globular KPs were self-explanatory and affected nearly all eyes. Globular KPs seem to be formed by hyperreflective cells with large nuclei and prominent nucleoli, similar to atypical lymphocytes in vitreous cytology. IVCM could provide more insight into the morphological traits of KPs than clinical observation, highlighting its potential for identifying VRL involving the anterior segment. [ABSTRACT FROM AUTHOR]

Several scientific themes are reviewed in the context of the 75-year period relevant to this special platinum issue of Radiation Research. Two criteria have been considered in selecting the scientific themes. One is the exposure of the associated research activity in the annual meetings of the Radiation Research Society (RRS) and in the publications of the Society's Journal, thus reflecting the interest of members of RRS. The second criteria is a focus on contributions from Australian members of RRS. The first theme is the contribution of radiobiology to radiation oncology, featuring two prominent Australian radiation oncologists, the late Rod Withers and his younger colleague, Lester Peters. Two other themes are also linked to radiation oncology; preclinical research aimed at developing experimental radiotherapy modalities, namely microbeam radiotherapy (MRT) and Auger endoradiotherapy. The latter has a long history, in contrast to MRT, especially in Australia, given that the associated medical beamline at the Australian Synchrotron in Melbourne only opened in 2011. Another theme is DNA repair, which has a trajectory parallel to the 75-year period of interest, given the birth of molecular biology in the 1950s. The low-dose radiobiology theme has a similar timeline, predominantly prompted by the nuclear era, which is also connected to the radioprotector theme, although radioprotectors also have a long-established potential utility in cancer radiotherapy. Finally, two themes are associated with biodosimetry. One is the micronucleus assay, highlighting the pioneering contribution from Michael Fenech in Adelaide, South Australia, and the other is the γ-H2AX assay and its widespread clinical applications. [ABSTRACT FROM AUTHOR]

Objectives: To determine the genetic effects of panoramic radiography on the epithelial cells of the buccal mucosa by examining the micronucleus formation in these cells. Materials and Methods: In this cross‐sectional study, exfoliative cytology samples were prepared from the buccal mucosa of 36 patients immediately before and 10 days after panoramic radiography. The samples were prepared using liquid‐based cytology with Papanicolaou staining. The slides were simultaneously evaluated by two expert pathologists and the ratio of the number of cells with micronuclei to the total number of cells on the slide was reported as a percentage. Data analysis was done using paired‐samples T test, Pearson's correlation coefficient, and covariance analysis (α = 0.05). Results: The study sample consisted of 24 (66.67%) males and 12 females (33.33%) with a mean (SD) age of 27.36 (8.19) years. The frequency of cells with micronucleus before and after panoramic radiography was not statistically different (p = 0.468). Additionally, the frequency of micronucleated cells was not correlated with age (p = 0.737) and sex (p = 0.211). Conclusion: Panoramic exposure slightly increased the frequency of cells with micronucleus in epithelial cells of the buccal mucosa. However, this increase was not statistically significant. [ABSTRACT FROM AUTHOR]

Familial Mediterranean Fever (FMF) is an inherited autoinflammatory disease. In this study, we aimed to assess chromosomal DNA damage and cell proliferation by using cytokinesis-block micronucleus cytome (CBMN-cyt) assay in the peripheral blood lymphocytes of untreated FMF patients carrying M694V and R202Q mutations, which are the most common MEFV gene mutations in Turkish society. The study included 20 untreated FMF patients with M694V and R202Q mutations and 20 healthy individuals of similar age and sex as the control group. Micronucleus (MN), nucleoplasmic bridges (NPBs), and nuclear buds (NBUDs) were scored in the obtained bi-nucleated (BN) cells. Additionally, the nuclear division index (NDI) was calculated using the scores of mononuclear, binuclear, and multinuclear cells. We found that MN and NPBs frequencies in FMF patients were significantly higher than in controls, and number of metaphases was significantly lower (respectively, p < 0.05, p < 0.01, and p < 0.01). However, there was no significant difference in NBUDs frequencies and NDI values between FMF patients and controls (p > 0.05). Our study is the first to evaluate FMF patients’ lymphocytes using the CBMN-cyt assay, as no previous research has been found in this respect. Increased MN and NPB frequencies may be useful as biomarkers for chromosomal DNA damage, and may indicate a potential for elevated cancer risk in untreated FMF patients. [ABSTRACT FROM AUTHOR]

Recent studies have highlighted the impact of both transcription and transcripts on 3D genome organization, particularly its dynamics. Here, we propose a deep learning framework, called AkitaR, that leverages both genome sequences and genome-wide RNA-DNA interactions to investigate the roles of chromatin-associated RNAs (caRNAs) on genome folding in HFFc6 cells. In order to disentangle the cis- and trans-regulatory roles of caRNAs, we have compared models with nascent transcripts, trans-located caRNAs, open chromatin data, or DNA sequence alone. Both nascent transcripts and trans-located caRNAs improve the models' predictions, especially at cell-type-specific genomic regions. Analyses of feature importance scores reveal the contribution of caRNAs at TAD boundaries, chromatin loops and nuclear sub-structures such as nuclear speckles and nucleoli to the models' predictions. Furthermore, we identify non-coding RNAs (ncRNAs) known to regulate chromatin structures, such as MALAT1 and NEAT1, as well as several new RNAs, RNY5, RPPH1, POLG-DT and THBS1-IT1, that might modulate chromatin architecture through trans-interactions in HFFc6. Our modeling also suggests that transcripts from Alus and other repetitive elements may facilitate chromatin interactions through trans R-loop formation. Our findings provide insights and generate testable hypotheses about the roles of caRNAs in shaping chromatin organization. Here the authors report that chromatin-associated RNAs (caRNAs) could play both cis and trans-regulatory roles in establishing cell-type-specific chromatin architecture by showing their capability to improve the prediction of genome folding. [ABSTRACT FROM AUTHOR]

AbstractNucleolus is the most conspicuous sub-nuclear compartment that is well known as the site of RNA polymerase I-mediated rDNA transcription and assembly of ribosome subunits in eukaryotes. Recent studies on mammalian cells suggest that functions of nucleolus are not limited to ribosome biogenesis, and that nucleolus is involved in a diverse array of nuclear and cellular processes such as DNA repair, stress responses, and protein sequestration. In fungi, knowledge of nucleolus and its functions was primarily gleaned from the budding yeast. However, little is known about nucleolus of the filamentous fungi. Considering that the filamentous fungi are multi-cellular eukaryotes and thus distinct from the yeast in many aspects, researches on nucleoli of filamentous fungi would have the potential to uncover the evolution of nucleolus and its roles in the diverse cellular processes. Here we provide a brief up-to-date overview of nucleolus in general, and evidence suggesting their roles in fungal physiology and development. [ABSTRACT FROM AUTHOR]

The effects of genotoxic agents on DNA and the processes involved in their removal have been thoroughly studied; however, very little is known about the mechanisms governing the reinstatement of cellular activities after DNA repair, despite restoration of the damage‐induced block of transcription being essential for cell survival. In addition to impeding transcription, DNA lesions have the potential to disrupt the precise positioning of chromatin domains within the nucleus and alter the meticulously organized architecture of the nucleolus. Alongside the necessity of resuming transcription mediated by RNA polymerase 1 and 2 transcription, it is crucial to restore the structure of the nucleolus to facilitate optimal ribosome biogenesis and ensure efficient and error‐free translation. Here, we examine the current understanding of how transcriptional activity from RNA polymerase 2 is reinstated following DNA repair completion and explore the mechanisms involved in reassembling the nucleolus to safeguard the correct progression of cellular functions. Given the lack of information on this vital function, this Review seeks to inspire researchers to explore deeper into this specific subject and offers essential suggestions on how to investigate this complex and nearly unexplored process further. [ABSTRACT FROM AUTHOR]

AbstractPsychotria carthagenensis is a shrubby plant, often consumed by traditional populations in religious rituals. Previous studies have shown that this plant’s infusion can inhibit the activity of Acetylcholinesterase (AChE) in rats. Despite the therapeutic potential, there is a lack of research regarding its possible toxicological and genotoxic effects. Hence, this study aimed to analyze the chemical profile of the ethanol extract from P. carthagenensis leaves by LC-DAD-MS and assess its possible toxicity and genotoxicity in zebrafish (Danio rerio). Adult zebrafish (N = 9/group) were exposed at different concentrations and the LC50 was calculated. Frequencies of micronucleus (MN) and nuclear abnormalities (NA) were estimated for genotoxic effects, and degree of tissue changes (DTC) was used to assess the liver and gill histopathology. From the LC-DAD-MS analyses, the identified compounds included N-fructosyl valine, ethyl hexoside, 5-O-E-caffeoylquinic acid, N-feruloylagmatime, roseoside, di-O-deoxyhexoyl-hexosyl quercetin, loiolide, and oleamide. The calculated values of LC50 did not vary significantly during the time of exposure. At the concentrations of 1.25, 2.5, 3.75, 5, 7.5, 10 and 15 mg/L, there was no genotoxicity, and only low to moderate toxicity for the tissues was observed, despite mortality of 100% at doses of 20–100 mg/L of P. carthagenensis ethanolic leaf extract. There were changes in cytoplasm of hepatocytes at 1.25 mg/L, and karyorrhexis, karyolysis and megalocytosis at 10 mg/L. In the gills, the alterations were primary lamellar hyperplasia in all concentrations, and at 10 mg/L, secondary lamellar edema and vascular hyperemia were common. Additionally, the chemical composition of P. carthagenensis was expanded. [ABSTRACT FROM AUTHOR]

The nucleolus is the largest membraneless organelle and nuclear body in mammalian cells. It is primarily involved in the biogenesis of ribosomes, essential macromolecular machines responsible for synthesizing all proteins required by the cell. The assembly of ribosomes is evolutionarily conserved and accounts for the most energy-consuming cellular process needed for cell growth, proliferation, and homeostasis. Despite the significance of this process, the substructural mechanistic principles of the nucleolar function in preribosome biogenesis have only recently begun to emerge. Here, we provide a new perspective using advanced super-resolution microscopy and single-molecule MINFLUX nanoscopy on the mechanistic principles governing ribosomal RNA-seeded nucleolar formation and the resulting tripartite suborganization of the nucleolus driven, in part, by liquid–liquid phase separation. With recent advances in the cryogenic electron microscopy (cryoEM) structural analysis of ribosome biogenesis intermediates, we highlight the current understanding of the step-wise assembly of preribosomal subunits in the nucleolus. Finally, we address how novel anticancer drug candidates target early steps in ribosome biogenesis to exploit these essential dependencies for growth arrest and tumor control. [ABSTRACT FROM AUTHOR]

The human Origin Recognition Complex (ORC) is required not only for the initiation of DNA replication, but is also implicated in diverse cellular functions, including chromatin organization, centrosome biology, and cytokinesis. The smallest subunit of ORC, Orc6, is poorly conserved amongst eukaryotes. Recent studies from our laboratory have suggested that human Orc6 is not required for replication licensing, but is needed for S-phase progression. Further, ATR-dependent phosphorylation of Orc6 at T229 is implicated in DNA damage response during S-phase. In this study, we demonstrate that the CDK-dependent phosphorylation of Orc6 at T195 occurs during mitosis. While the phosphorylation at T195 does not seem to be required to exit mitosis, cells expressing the phosphomimetic T195E mutant of Orc6 impede S-phase progression. Moreover, the phosphorylated form of Orc6 associates with ORC more robustly, and Orc6 shows enhanced association with the ORC outside of G1, supporting the view that Orc6 may prevent the role of Orc1-5 in licensing outside of G1. Finally, Orc6 and the phosphorylated Orc6 localize to the nucleolar organizing centers and regulate ribosome biogenesis. Our results suggest that phosphorylated Orc6 at T195 prevents replication. [ABSTRACT FROM AUTHOR]

Tail regeneration in lizards derives from the formation of a regenerative blastema. Numerous snoRNAs exclusively up-regulated in the regenerating tail but absent in the scarring limb of the lizard Podarcis muralis have been detected suggesting they are key genes for regeneration. While most snord-, snora-and scarna-RNAs are activators of protein synthesis and cell proliferation (oncogenes) some may also be tumour suppressors. A tail blastema of 2-3 mm in length consists of proliferating mesenchymal cells, fibroblasts and keratinocytes with active nucleoli, rosette-patterned ribosomes and few rough endoplasmic cisternae. In few days, the blastema grows into a new tail indicating intense protein synthesis within this short period. A quantitative RT-PCR analysis of snord87, snord26, snord74, snora63, scarna11, U2 and U4 shows that, aside snord87, the other ncRNAs are up-regulated, particularly, U2, U4 and scarna11. These ncRNAs might regulate the rate of production of ribosomes from the nucleolus (snora-and snord-RNAs), the splicing process (snord-and scarna-RNAs, U2 and U4), the speed of protein synthesis (snora-and snord-RNAs) and cell proliferation in the blastema. These non-coding- RNAs are hypothesized to intensify the production of more functional ribosomes that accelerate the rate of protein synthesis and rapid growth of the blastema into a new tail. [ABSTRACT FROM AUTHOR]

This study aimed to investigation the effect of environmental changing associated with the elevation gradient on cytogenetic traits of Taraxacum officinale during its invasion in high altitude areas. We chose common dandelion as the object of research, because representatives of this species are able to inhabit a large range of elevations. The cytogenetic characteristics of the plants growing at altitudes of 200, 600, 1300, 2050, 2700 and 3050 m a.s.l in the Central Caucasus region have been studied. We determined the frequency of micronuclei, chromosomal aberrations, mitotic index and chromosome number in the cells of the apical root meristem using seed progeny of plants growing at different elevations. In the populations of natural habitats studied by us, all individuals were triploid with the exception of single ones. The level of ploidy increased in accordance with the altitude gradient when T. officinale invade in the disturbed highland areas. In the seed progeny of highland plants cell proliferation and the ratio of mitosis phases do not change along the elevation gradient. The frequency of chromosome aberrations increased by 1.3–4.6 times in the highland populations. The main types of mutations were fragments, lost and lagging chromosomes. The reasons for this are the influence of unfavorable conditions of high-altitude areas and high level of ploidy in plants of these populations. Despite the significant increase in the frequency of chromosome aberrations, no similar increase in the frequency of micronuclei resulting from these mutations was found. [ABSTRACT FROM AUTHOR]

Identifying genetic modifiers of familial amyotrophic lateral sclerosis (ALS) may reveal targets for therapeutic modulation with potential application to sporadic ALS. GGGGCC (G4C2) repeat expansions in the C9orf72 gene underlie the most common form of familial ALS, and generate toxic arginine-containing dipeptide repeats (DPRs), which interfere with membraneless organelles, such as the nucleolus. Here we considered senataxin (SETX), the genetic cause of ALS4, as a modifier of C9orf72 ALS, because SETX is a nuclear helicase that may regulate RNA-protein interactions involved in ALS dysfunction. After documenting that decreased SETX expression enhances arginine-containing DPR toxicity and C9orf72 repeat expansion toxicity in HEK293 cells and primary neurons, we generated SETX fly lines and evaluated the effect of SETX in flies expressing either (G4C2)58 repeats or glycine-arginine-50 [GR(50)] DPRs. We observed dramatic suppression of disease phenotypes in (G4C2)58 and GR(50) Drosophila models, and detected a striking relocalization of GR(50) out of the nucleolus in flies co-expressing SETX. Next-generation GR(1000) fly models, that show age-related motor deficits in climbing and movement assays, were similarly rescued with SETX co-expression. We noted that the physical interaction between SETX and arginine-containing DPRs is partially RNA-dependent. Finally, we directly assessed the nucleolus in cells expressing GR-DPRs, confirmed reduced mobility of proteins trafficking to the nucleolus upon GR-DPR expression, and found that SETX dosage modulated nucleolus liquidity in GR-DPR-expressing cells and motor neurons. These findings reveal a hitherto unknown connection between SETX function and cellular processes contributing to neuron demise in the most common form of familial ALS.

Abstract Heat stress (HS) impacts the nuclear proteome and, subsequently, protein activities in different nuclear compartments. In Arabidopsis thaliana, a short exposure to 37 °C leads to loss of the standard tripartite architecture of the nucleolus, the most prominent nuclear substructure, and, consequently, affects the assembly of ribosomes. Here, we report a quantitative label-free LC‒MS/MS (Liquid Chromatography coupled to tandem Mass Spectrometry) analysis to determine the nuclear proteome of Arabidopsis at 22 °C, HS (37 °C for 4 and 24 h), and a recovery phase. This analysis identified ten distinct groups of proteins based on relative abundance changes in the nucleus before, during and after HS: Early, Late, Transient, Early Persistent, Late Persistent, Recovery, Early-Like, Late-Like, Transient-Like and Continuous Groups (EG, LG, TG, EPG, LPG, RG, ELG, LLG, TLG and CG, respectively). Interestingly, the RNA polymerase I subunit NRPA3 and other main nucleolar proteins, including NUCLEOLIN 1 and FIBRILLARIN 1 and 2, were detected in RG and CG, suggesting that plants require increased nucleolar activity and likely ribosome assembly to restore protein synthesis after HS.

Nucleolus is the most conspicuous sub-nuclear compartment that is well known as the site of RNA polymerase I-mediated rDNA transcription and assembly of ribosome subunits in eukaryotes. Recent studies on mammalian cells suggest that functions of nucleolus are not limited to ribosome biogenesis, and that nucleolus is involved in a diverse array of nuclear and cellular processes such as DNA repair, stress responses, and protein sequestration. In fungi, knowledge of nucleolus and its functions was primarily gleaned from the budding yeast. However, little is known about nucleolus of the filamentous fungi. Considering that the filamentous fungi are multi-cellular eukaryotes and thus distinct from the yeast in many aspects, researches on nucleoli of filamentous fungi would have the potential to uncover the evolution of nucleolus and its roles in the diverse cellular processes. Here we provide a brief up-to-date overview of nucleolus in general, and evidence suggesting their roles in fungal physiology and development.

Stem cell loss in aging and disease is associated with nuclear deformation. Yet, how nuclear shape influences stem cell homeostasis is poorly understood. We investigated this connection using Drosophila germline stem cells, as survival of these stem cells is compromised by dysfunction of the nuclear lamina, the extensive protein network that lines the inner nuclear membrane and gives shape to the nucleus. To induce nuclear distortion in germline stem cells, we used the GAL4-UAS system to increase expression of the permanently farnesylated nuclear lamina protein, Kugelkern, a rate limiting factor for nuclear growth. We show that elevated Kugelkern levels cause severe nuclear distortion in germline stem cells, including extensive thickening and lobulation of the nuclear envelope and nuclear lamina, as well as alteration of internal nuclear compartments. Despite these changes, germline stem cell number, proliferation, and female fertility are preserved, even as females age. Collectively, these data demonstrate that disruption of nuclear architecture does not cause a failure of germline stem cell survival or homeostasis, revealing that nuclear deformation does not invariably promote stem cell loss. [Display omitted] • Nuclear lamina (NL) assembly is unaffected by nuclear envelope expansion. • Nuclear envelope (NE) expansion alters structure of internal nuclear compartments. • Excess NE and NL do not interfere with centrosome remodeling in GSC mitosis. • NL distortion is not sufficient to promote a failure of GSC survival or homeostasis. • Functional consequences of nuclear distortion are contextual. [ABSTRACT FROM AUTHOR]

We consider the problem of dividing the cost of a facility when agents can be ordered in terms of the needs they have for it, and accommodating an agent with a certain need allows accommodating all agents with lower needs at no extra cost. This problem is known as the "airport problem", the facility being the runway. We review the literature devoted to its study, and formulate a number of open questions. [ABSTRACT FROM AUTHOR]

Abstract With increasingly used assisted reproductive technology (ART), the acquisition of high-quality oocytes and early embryos has become the focus of much attention. Studies in mice have found that the transition of chromatin conformation from non-surrounded nucleolus (NSN) to surrounded nucleolus (SN) is essential for oocyte maturation and early embryo development, and similar chromatin transition also exists in human oocytes. In this study, we collected human NSN and SN oocytes and investigated their transcriptome. The analysis of differentially expressed genes showed that epigenetic functions, cyclin-dependent kinases and transposable elements may play important roles in chromatin transition during human oocyte maturation. Our findings provide new insights into the molecular mechanism of NSN-to-SN transition of human oocyte and obtained new clues for improvement of oocyte in vitro maturation technique.

Eribulin (ERI), clinically utilized for locally advanced or metastatic breast tumors, has shown potential links to the immune system. Notably, the cGAS-STING pathway, a key component of innate immunity, has gained prominence. Yet, limited reports explore ERI's effects on the cGAS-STING pathway. Additionally, the nuclear presence of cGAS remains poorly understood. This study uniquely delves into ERI's impact on both the cytosolic cGAS-STING pathway and nuclear cGAS. ERI enhances nuclear localization of cGAS, resulting in hyper-activation of the cGAS-STING pathway in triple-negative breast cancer cells. Reduction of cGAS heightened both cell proliferation and ERI sensitivity. In clinical data using ERI in a neo-adjuvant setting, patients with low cGAS cases exhibited reduced likelihood of achieving pathological complete response after ERI treatment. These findings illuminate the potential of cGAS and IFNβ as predictive biomarkers for ERI sensitivity, providing valuable insights for personalized breast cancer treatment strategies. [ABSTRACT FROM AUTHOR]

Different developmental genes shape frequent dynamic inter-chromosomal contacts with rDNA units in human and Drosophila cells. In the course of differentiation, changes in these contacts occur, coupled with changes in the expression of hundreds of rDNA-contacting genes. The data suggest a possible role of nucleoli in the global regulation of gene expression. However, the mechanism behind the specificity of these inter-chromosomal contacts, which are rebuilt in every cell cycle, is not yet known. Here, we describe the strong association of rDNA-contacting genes with numerous long intergenic non-coding RNAs (lincRNAs) in HEK293T cells and in initial and differentiated K562 cells. We observed that up to 600 different lincRNAs were preferentially co-expressed with multiple overlapping sets of rDNA-contacting developmental genes, and there was a strong correlation between the genomic positions of rDNA-contacting genes and lincRNA mappings. These two findings suggest that lincRNAs might guide the corresponding developmental genes toward rDNA clusters. We conclude that the inter-chromosomal interactions of rDNA-contacting genes with nucleoli might be guided by lincRNAs, which might physically link particular genomic regions with rDNA clusters. [ABSTRACT FROM AUTHOR]

Ribosome biogenesis is initiated in the nucleolus, a multiphase biomolecular condensate formed by liquid-liquid phase separation. The nucleolus is a powerful disease biomarker and stress biosensor whose morphology reflects function. Here we have used digital holographic microscopy (DHM), a label-free quantitative phase contrast microscopy technique, to detect nucleoli in adherent and suspension human cells. We trained convolutional neural networks to detect and quantify nucleoli automatically on DHM images. Holograms containing cell optical thickness information allowed us to define a novel index which we used to distinguish nucleoli whose material state had been modulated optogenetically by blue-light-induced protein aggregation. Nucleoli whose function had been impacted by drug treatment or depletion of ribosomal proteins could also be distinguished. We explored the potential of the technology to detect other natural and pathological condensates, such as those formed upon overexpression of a mutant form of huntingtin, ataxin-3, or TDP-43, and also other cell assemblies (lipid droplets). We conclude that DHM is a powerful tool for quantitatively characterizing nucleoli and other cell assemblies, including their material state, without any staining. Synopsis: Digital Holographic Microscopy (DHM) detects membraneless biomolecular condensates and membrane-bound organelles without staining. Correlative Fluorescence - Digital Holographic Microscopy (DHM), a label-free quantitative interferometric technique, detects nucleoli, a biomolecular condensate, and membrane-bound organelles without staining. Convolutional neural networks automatically segment holograms and quantify the nucleolus. Definition of the nucleolar optical thickness as a novel index for characterizing the material state of the nucleolus. Digital Holographic Microscopy (DHM) detects membraneless biomolecular condensates and membrane-bound organelles without staining. [ABSTRACT FROM AUTHOR]

Introduction: Gas station employees may be exposed to dangerous compounds that could cause cancer. This study aimed to analyze the effect of benzene exposure on the frequency of micronuclei in exfoliated buccal mucosa cells of Yogyakarta, Indonesia petrol station employees. Materials and methods: The exposed group included 15 gas station attendants, and the control group included 15 individuals who had never been exposed to benzene in gasoline. A cytobrush was used to collect buccal epithelial cells, which were subsequently spread onto slides. The specimens were subjected to Feulgen--Rosenbeck staining. Then, 1,000 cells were counted to determine the presence of micronuclei using a light microscope, and the results were statistically analyzed using an independent t-test (p < 0.05). Results: The mean frequencies of micronuclei were significantly greater in the exposed group than in the control group (p 0.001). The frequency of buccal mucosal micronuclei did not correlate with the length of exposure (working hours) or sex. Conclusion: Gas station attendants in Yogyakarta who are exposed to benzene from petrol vapors had more micronuclei than normal, which puts them at risk of substantial cytogenetic damage. [ABSTRACT FROM AUTHOR]

The RNA tailing machinery adds nucleotides to the 3'-end of RNA molecules that are implicated in various biochemical functions, including protein synthesis and RNA stability. Here, we report a role for the RNA tailing machinery as enzymatic modifiers of intracellular amyloidogenesis. A targeted RNA interference screen identified Terminal Nucleotidyl-transferase 4b (TENT4b/Papd5) as an essential participant in the amyloidogenic phase transition of nucleoli into solid-like Amyloid bodies. Full-length-and-mRNA sequencing uncovered starRNA, a class of unusually long untemplated RNA molecules synthesized by TENT4b. StarRNA consists of short rRNA fragments linked to long, linear mixed tails that operate as polyanionic stimulators of amyloidogenesis in cells and in vitro. Ribosomal intergenic spacer noncoding RNA (rIGSRNA) recruit TENT4b in intranucleolar foci to coordinate starRNA synthesis driving their amyloidogenic phase transition. The exoribonuclease RNA Exosome degrades starRNA and functions as a general suppressor of cellular amyloidogenesis. We propose that amyloidogenic phase transition is under tight enzymatic control by the RNA tailing and exosome axis. [ABSTRACT FROM AUTHOR]

Glufosinate-ammonium (GLA), an organophosphate herbicide, is released at high concentrations in the environment, leading to concerns over its potential genotoxic effects. However, few articles are available in the literature reporting the possible cellular and nuclear effects of this compound. We assessed, by in vitro and in vivo micronucleus assays, the genotoxicity of GLA on cultured human lymphocytes and Lymnaea stagnalis hemocytes at six concentrations: 0.010 (the established acceptable daily intake value), 0.020, 0.050, 0.100, 0.200, and 0.500 µg/mL. In human lymphocytes, our results reveal a significant and concentration-dependent increase in micronuclei frequency at concentrations from 0.100 to 0.500 μg/mL, while in L. stagnalis hemocytes, significant differences were found at 0.200 and 0.500 μg/mL. A significant reduction in the proliferation index was observed at all tested concentrations, with the only exception of 0.010 μg/mL, indicating that the exposure to GLA could lead to increased cytotoxic effects. In L. stagnalis, a significant reduction in laid eggs and body growth was also observed at all concentrations. In conclusion, we provided evidence of the genomic and cellular damage induced by GLA on both cultured human lymphocytes and a model organism's hemocytes; in addition, we also demonstrated its effects on cell proliferation and reproductive health in L. stagnalis. [ABSTRACT FROM AUTHOR]

Background: Sperm motility is an essential factor in ensuring the fertility of males. Sperm mitochondria play a significant role in the generation of energy as well as the metabolism of sperm. The mitochondria nucleolus is essential for several sperm activities, such as sperm capping, hyperactivation, acrosome reactions, and oocyte fusion. Therefore, as the mitochondria are the basic regulators of sperm motility, mitochondrial membrane potential (MMP) is used to assess the mitochondrial activity and integrity of sperm. This is evaluated by examination of MMP, which may be achieved by using fluorescent dyes like the JC-1 probe. Objectives: To examine the correlation between MMP and sperm motility. Materials and methods: This study included semen samples of 60 males that were separated into two groups: 30 normomozoospermic and 30 asthenozoospermic. The samples were collected in the infertility clinic at the High Institute for Infertility Diagnosis and Assisted Reproductive Technologies, Al-Nahrain University and Um Al-Banin Center for management and in vitro fertilization. The collected samples were processed for seminal fluid analysis and evaluated according to the recommendations of WHO 2021 using an MMP-Assay kit with JC-1 dye and examined by fluorescent microscope for evaluation. Results: A positive significant correlation between subjects’ sperms motility percentage and active red-fluorescence MMP intensity (Red MMP) (P-value, 0.05, r = 0.406; P-value = 0.008). The MMP or activity plays an essential role in sperm motility and male fertility. The red MMP values in subjects with normal sperm motility were 10.22 ± 1.54 and showed a relatively higher reading in comparison to those readings of subjects group with low sperms motility (4.70 ± 0.91). Subjects with normal sperm motility showed a high MMP intensity (P-value = 0.004). Conclusion: Normal MMP is crucial for normal sperm motility. The sperm motility is proportionate to the MMP, or activity. [ABSTRACT FROM AUTHOR]

Micronuclei, detected through the cytokinesis-block micronucleus assay, are valuable indicators of ionizing radiation exposure, especially in short-term lymphocyte cultures. The peripheral human blood lymphocyte assay is recognized as a prime candidate for automated biodosimetry. In a prior project at the Columbia University Center for Radiological Research, we automated this assay using the 96-well ANSI/SLAS microplate standard format and relied on established biotech robotic systems named Rapid Automated Biodosimetry Tool (RABiT). In this study, we present the application of a similar automated biotech setup at an external high-throughput facility (RABiT-III) to implement the same automated cytokinesis-block micronucleus assay. Specifically, we employed the Agilent BRAVO liquid-handling system and GE IN Cell Analyzer 6000 imaging system in conjunction with the PerkinElmer Columbus image data storage and analysis system. Notably, this analysis system features an embedded PhenoLOGIC machine learning module, simplifying the creation of cell classification algorithms for CBMN assay image analysis and enabling the generation of radiation dose-response curves. This investigation underscores the adaptability of the RABiT-II CBMN protocol to diverse RABiT-III biotech robotic platforms in non-specialized biodosimetry centers. Furthermore, it highlights the advantages of machine learning in rapidly developing algorithms crucial for the high-throughput automated analysis of RABiT-III images. [ABSTRACT FROM AUTHOR]

Two endemic Anatolian nemacheilids were studied cytogenetically for the first time. Diploid chromosome numbers, chromosome morphologies in the karyotypes and also C-band and Ag-NOR banding properties were recorded for the two species of Oxynoemacheilus. The diploid chromosome number is 50 and karyotypes contained 34 biarmed and 16 monoarmed chromosomes in Oxynoemacheilus axylos Yoğurtçuoğlu et al. 2022. In O. nasreddini Yoğurtçuoğlu et al. 2021, there are 30 biarmed and 20 monoarmed chromosomes. No heteromorphic sex chromosomes were determined. C-band patterns and the number of Ag-NORs were different between the two studied species. [ABSTRACT FROM AUTHOR]

Recently, nuclear abnormalities in avian erythrocytes have been used as biomarkers of genotoxicity in several species. Anomalous shapes are usually detected in the nuclei by means of microscopy inspection. However, due to inter- and intra-observer variability, the classification of these blood cell abnormalities could be problematic for replicating research. Deep learning, as a powerful image analysis technique, can be used in this context to improve standardization in identifying the biological configurations of medical and veterinary importance. In this study, we present a standardized deep learning model for identifying and classifying abnormal shapes in erythrocyte nuclei in blood smears of the hemispheric and synanthropic Kelp Gull (Larus dominicanus). We trained three convolutional backbones (ResNet34 and ResNet50 architectures) to obtain models capable of detecting and classifying these abnormalities in blood cells. The analysis was performed at three discrimination levels of classification, with broad categories subdivided into increasingly specific subcategories (level 1: "normal", "abnormal", "other"; level 2: "normal", "ENAs", "micronucleus", "other"; level 3: "normal", "irregular", "displaced", "enucleated", "micronucleus", "other"). The results were more than adequate and very similar in levels 1 and 2 (F1-score 84.6% and 83.6%, and accuracy 83.9% and 82.6%). In level 3, performance was lower (F1-score 65.9% and accuracy 80.8%). It can be concluded that the level 2 analysis should be considered the most appropriate as it is more specific than level 1, with similar quality of performance. This method has proven to be a fast, efficient, and standardized approach that reduces the dependence on human supervision in the classification of nuclear abnormalities in avian erythrocytes, and can be adapted to be used in similar contexts with reduced effort. [ABSTRACT FROM AUTHOR]

DNA topoisomerase I can contribute to cancer genome instability. During catalytic activity, topoisomerase I forms a (cc BY). transient intermediate, topoisomerase I-DNA cleavage complex (Top1cc) to allow strand rotation and duplex relaxation, which can lead to elevated levels of DNA-RNA hybrids and micronuclei. To comprehend the underlying mechanisms, we have integrated genomic data of Top1cc-triggered hybrids and DNA double-strand breaks (DSBs) shortly after Top1cc induction, revealing that Top1ccs increase hybrid levels with different mechanisms. DSBs are at highly transcribed genes in early replicating initiation zones and overlap with hybrids downstream of accumulated RNA polymerase II (RNAPII) at gene 5'-ends. A transcription factor IIS mutant impairing transcription elongation further increased RNAPII accumulation likely due to backtracking. Moreover, Top1ccs can trigger micronuclei when occurring during late G1 or early/mid S, but not during late S. As micronuclei and transcription-replication conflicts are attenuated by transcription factor IIS, our results support a role of RNAPII arrest in Top1cc-induced transcriptionreplication conflicts leading to DSBs and micronuclei. [ABSTRACT FROM AUTHOR]

We have previously shown that unconventional myosin VI (MVI), a unique actin- based motor protein, shuttles between the cytoplasm and nucleus in neurosecretory PC12 cells in a stimulation-dependent manner and interacts with numerous proteins involved in nuclear processes. Among the identified potential MVI partners was nucleolin, a major nucleolar protein implicated in rRNA processing and ribosome assembly. Several other nucleolar proteins such as fibrillarin, UBF (upstream binding factor), and B23 (also termed nucleophosmin) have been shown to interact with MVI. A bioinformatics tool predicted the presence of the nucleolar localization signal (NoLS) within the MVI globular tail domain, and immunostaining confirmed the presence of MVI within the nucleolus. Depletion of MVI, previously shown to impair PC12 cell proliferation and motility, caused disorganization of the nucleolus and rough endoplasmic reticulum (rER). However, lack of MVI does not affect nucleolar transcription. In light of these data, we propose that MVI is important for nucleolar and ribosome maintenance but not for RNA polymerase 1-related transcription. [ABSTRACT FROM AUTHOR]

This paper introduces the new class of two-bound core games, where the core can be described by a lower bound and an upper bound on the payoffs of the players. Many classes of games turn out to be two-bound core games. We show that the core of each two-bound core game can be described equivalently by the pair of exact core bounds, and study to what extent the exact core bounds can be stretched while retaining the core description. We provide explicit expressions of the nucleolus for two-bound core games in terms of all pairs of bounds describing the core, using the Talmud rule for bankruptcy problems, and study to what extent these expressions are robust against game changes. [ABSTRACT FROM AUTHOR]

With increasingly used assisted reproductive technology (ART), the acquisition of high-quality oocytes and early embryos has become the focus of much attention. Studies in mice have found that the transition of chromatin conformation from non-surrounded nucleolus (NSN) to surrounded nucleolus (SN) is essential for oocyte maturation and early embryo development, and similar chromatin transition also exists in human oocytes. In this study, we collected human NSN and SN oocytes and investigated their transcriptome. The analysis of differentially expressed genes showed that epigenetic functions, cyclin-dependent kinases and transposable elements may play important roles in chromatin transition during human oocyte maturation. Our findings provide new insights into the molecular mechanism of NSN-to-SN transition of human oocyte and obtained new clues for improvement of oocyte in vitro maturation technique. [ABSTRACT FROM AUTHOR]

Although studies have demonstrated that genome instability is accumulated in patients with Alzheimer's disease (AD), the specific types of genome instability linked to AD pathogenesis remain poorly understood. Here, we report the first characterization of the age‐ and sex‐related trajectories of telomere length (TL) and micronuclei in APP/PS1 mice model and wild‐type (WT) controls (C57BL/6). TL was measured in brain (prefrontal cortex, cerebellum, pituitary gland, and hippocampus), colon and skin, and MN was measured in bone marrow in 6‐ to 14‐month‐old mice. Variation in TL was attributable to tissue type, age, genotype and, to a lesser extent, sex. Compared to WT, APP/PS1 had a significantly shorter baseline TL across all examined tissues. TL was inversely associated with age in both genotypes and TL shortening was accelerated in brain of APP/PS1. Age‐related increase of micronuclei was observed in both genotypes but was accelerated in APP/PS1. We integrated TL and micronuclei data with data on cognition performance and brain amyloidosis. TL and micronuclei were linearly correlated with cognition performance or Aβ40 and Aβ42 levels in both genotypes but to a greater extent in APP/PS1. These associations in APP/PS1 mice were dominantly driven by females. Together, our findings provide foundational knowledge to infer the TL and micronuclei trajectories in APP/PS1 mice during disease progression, and strongly support that TL attrition and micronucleation are tightly associated with AD pathogenesis in a female‐biased manner. [ABSTRACT FROM AUTHOR]

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate the safety of 2‐methyl‐1‐(2‐(5‐(p‐tolyl)‐1H‐imidazol‐2‐yl)piperidin‐1‐yl)butan‐1‐one [FL‐no: 16.134] as a new flavouring substance, in accordance with Regulation (EC) No 1331/2008. The substance has not been reported to occur naturally and is chemically synthesised. In food, it is intended to be used as a flavouring substance only in chewing gum. The chronic dietary exposure to [FL‐no: 16.134] was estimated to be 45 μg/person per day for a 60‐kg adult and 28.4 μg/person per day for a 15‐kg 3‐year‐old child. [FL‐no: 16.134] did not show genotoxicity in a bacterial reverse mutation test and an in vitro mammalian cell micronucleus assay. Based on the submitted toxicokinetic and metabolism data, it can be predicted that the flavouring substance is metabolised to innocuous products only. The Panel derived a lower confidence limit of the benchmark dose (BMDL) of 0.71 mg/kg bw per day for a 20% increase in the relative thyroid (including parathyroid) weight observed in a 90‐day toxicity study in rats. Based on this BMDL, adequate margins of exposure of 887 and 374 could be calculated for adults and children, respectively. The Panel concluded that there is no safety concern for [FL‐no: 16.134], when used as a flavouring substance at the estimated level of dietary exposure, based on the intended use and use levels as specified in Appendix B. The Panel further concluded that the combined exposure to [FL‐no: 16.134] from its use as a food flavouring substance and from its presence in toothpaste and mouthwash is also not of safety concern. [ABSTRACT FROM AUTHOR]

The current Organisation for Economic Co-Operation and Development test guideline number 487 (OECD TG No. 487) provides instruction on how to conduct the in vitro micronucleus assay. This assay is one of the gold standard approaches for measuring the mutagenicity of test items; however, it is directed at testing low molecular weight molecules and may not be appropriate for particulate materials (e.g. engineered nanoparticles [ENPs]). This study aimed to adapt the in vitro micronucleus assay for ENP testing and underpins the development of an OECD guidance document. A harmonized, nano-specific protocol was generated and evaluated by two independent laboratories. Cell lines utilized were human lymphoblastoid (TK6) cells, human liver hepatocytes (HepG2) cells, Chinese hamster lung fibroblast (V79) cells, whole blood, and buffy coat cells from healthy human volunteers. These cells were exposed to reference ENPs from the Joint Research Council (JRC): SiO2 (RLS-0102), Au5nm and Au30nm (RLS-03, RLS-010), CeO2 (NM212), and BaSO4 (NM220). Tungsten carbide-cobalt (WC/Co) was used as a trial particulate positive control. The chemical controls were positive in all cell cultures, but WC/Co was only positive in TK6 and buffy coat cells. In TK6 cells, mutagenicity was observed for SiO2- and both Au types. In HepG2 cells, Au5nm and SiO2 showed sub-two-fold increases in micronuclei. In V79 cells, whole blood, and buffy coat cells, no genotoxicity was detected with the test materials. The data confirmed that ENPs could be tested with the harmonized protocol, additionally, concordant data were observed across the two laboratories with V79 cells. WC/Co may be a suitable particulate positive control in the in vitro micronucleus assay when using TK6 and buffy coat cells. Detailed recommendations are therefore provided to adapt OECD TG No. 487 for testing ENP. [ABSTRACT FROM AUTHOR]

The present study was carried out during 2019-2023 seasons to produce the breeder’s seed of Super Giza 94 cultivar. At the end of the 2019 season, fifty-six plants representing Giza 94 cultivar type were selected from the nursery to form the increase lines A. In 2020 season, the selfed seeds of the progenies of the 56 selected type plants were grown in number of rows as the amount of seeds allowed conveniently named increased lineA. According to the determination values of both agronomic and fiber characteristics on bulked families of increaseA, 17 families were selected from increaseA to form increase B in 2021. The 17 selected families as well as the three latest strains of Super Giza 94 cultivar were evaluated for yield, yield components and fiber properties. In 2022 season, according to the results of yield trail, the best six families representing the type of Super Giza 94 cultivar were selected from increase B and their selfed seeds were carefully massed together to form increase C. It was planted in an area of about 35 feddans. In 2023 season, it was also propagated as new nucleolus (breeder’s seed) under the name of season (Super Giza 94 nucleolus/2023) in about 332 feddans.The results showed that performing the process of self-pollination with continuous selection, which takes place every season, is considered necessary to maintain genetic purity and eliminate any off-type plants from Super Giza 94 breeding population as a result of highly homozygous in minor genes or recombination among themselves. [ABSTRACT FROM AUTHOR]