Novel cellular factors involved in regulation of BRCA2-driven homologous recombination in Ustilago maydis

Maintaining genome integrity is critical for all organisms, requiring efficient DNA repair mechanisms to counteract damage from both internal and external sources. Homologous recombination (HR) is a conserved and accurate pathway for repairing DNA double-strand breaks (DSBs). While yeast uses Rad52 as a central HR mediator, higher eukaryotes, including humans, rely on BRCA2. The phytopathogenic fungus Ustilago maydis possesses a BRCA2 homolog, Brh2, and an HR system strikingly similar to that of humans, making it an excellent model for studying recombination. To uncover novel HR regulators, we conducted a genetic screen for suppressors of hydroxyurea (HU) sensitivity in blm mutants. Blm encodes a RecQ-family helicase, and its loss causes defects in replication-associated repair. The screen identified eight suppressor genes: three known HR factors (rad51, dna2, and mph), paraplegin (nuclear-encoded metalloprotease protein that is a member of the AAA protein family, that is located to the inner mitochondrial membrane) and four novel genes—rec3, zdr1, bls9, and bls2. • Rec3 is a Rad51-family ATPase essential for allelic recombination and meiosis, and shows a strong functional connection with Brh2. • Zdr1 is a C2H2-type zinc finger protein; although its deletion does not overtly affect HR, it contributes to general DNA repair processes. • Bls9 and Bls2 are uncharacterized proteins, but Bls9 is involved in HR between chromosome homologs, while Bls2 shows a slow-growth phenotype. Importantly, deletions of rec3, zdr1, bls2, and paraplegin also suppress HU sensitivity in Δgen1 and Δmus81 mutants, suggesting broader roles in recombination-associated repair. In contrast, bls9 deletion does not rescue HU sensitivity in Δgen1, indicating functional specificity. These newly identified factors expand our understanding of HR regulation and provide insights into the complexity and coordination of DNA repair pathways in eukaryotic cells.Book of abstract: 8th EU-US Conference on endogenous DNA damage and repair, TRONDHEIM, NTNU October 5th—8th | 202

Gut Microbiota as a Potential Target for Improving Immunotherapy

Immune-mediated diseases, including cancer and autoimmune disorders, are a growing global health burden. While immune checkpoint inhibitors (ICI)s and immunogenic cells have achieved significant success in oncology, approaches involving immunosuppressive immune cells are under investigation for autoimmune diseases. Increasing evidence highlights the gut microbiota as an important factor influencing immunotherapy outcomes. Clinical and preclinical data show that greater microbial diversity and enrichment of beneficial taxa correlate with improved therapeutic responses and fewer immune-related adverse events in ICI-treated patients. Our findings demonstrated that specific members of gut microbiota associate with the differentiation of dendritic cells (DC) with more pronounced immunogenic properties, which could be leveraged to improve the efficacy of DC-based anti-cancer vaccines. On the other hand, by using the animal model of multiple sclerosis, we demonstrated that the efficacy of myeloid-derived suppressor cells (MDSC) in attenuation of the disease symptoms is followed by preservation of gut microbiota with an immunosuppressive metabolic profile. These data support the idea that interventions based on specific probiotics, dietary fibres, and faecal microbiota transplantation (FMT) could be used to improve the antitumor and anti-inflammatory effects of therapies.Imunski posredovane bolesti, uključujući kancer i autoimunske bolesti, predstavljaju sve veći globalni zdravstveni izazov. Dok su terapije sa inhibitorima imunskih kontrolnih tačaka (eng. immune checkpoint inhibitors, ICI) i imunogenim ćelijama postigle značajan uspeh u onkologiji, pristupi zasnovani na imunosupresivnim ćelijama istražuju se u terapiji autoimunskih bolesti. Sve veći broj studija ukazuje da je mikrobiota creva važan faktor koji utiče na ishod imunoterapije. Klinički i preklinički podaci pokazuju da veći diverzitet mikrobiote creva i prisustvo “korisnih” taksona koreliraju sa boljim terapijskim odgovorima i manjim brojem neželjenih efekata kod pacijenata lečenih ICI terapijom. Naša istraživanja pokazala su da pojedini predstavnici mikrobiote creva utiču na diferencijaciju dendritskih ćelija sa izraženijim imunogenim svojstvima, što se može iskoristiti za unapređenje efikasnosti vakcina protiv tumora. S druge strane, korišćenjem životinjskog modela multiple skleroze pokazali smo da je terapijska efikasnost supresorskih ćelija mijeloidnog porekla u ublažavanju simptoma bolesti praćena očuvanjem mikrobiote sa imunosupresivnim metaboličkim profilom. Ovi podaci podržavaju ideju da bi intervencije zasnovane na specifičnim probioticima, dijetetskim vlaknima ili transplantaciji fekalne mikrobiote mogle doprineti jačanju antitumorskih i antiinflamatornih efekata terapija

ENGINEERING MICROBIAL PLATFORMS FOR SIMULTANEOUS BIODEGRADATION AND UPCYCLING OF PCL

Nowadays, the accumulation of plastic waste in the environment has become a significant global concern, with long-lasting ecological and health impacts. This has driven the urgent need for novel strategies, particularly those targeting the degradation of polyesters, which are widely used but poorly degraded in natural environments [1]. Biological approaches, particularly those utilizing microorganisms, offer a sustainable alternative for addressing plastic waste [2]. In this study, we evaluated the ability of various microbial strains to metabolize polycaprolactone monomers. These included Ralstonia eutropha H16, newly isolated pigmented Streptomyces isolates, Streptomyces albus wild-type strain, as well as a strain evolved via adaptive laboratory evolution, which was selected to better utilize the PCL monomer as a sole carbon source. Initial screening revealed variable growth across the studied microorganisms, which are known to produce valuable bioproducts, such as bioplastics, biopigments, and antibiotics [3] [4]. Additionally, aiming to construct strains that achieve polymer degradation and further metabolize the monomers, plasmids harboring selected polyesterase genes, Se1JFR [5] or DmPETase [6], were introduced into R. eutropha and Streptomyces species. Transformed strains were identified and further analyzed for their polyester-degrading abilities by growth assessment as well as the determination of esterase activity in culture supernatants. Overall, this work contributes to the broader field of microbial upcycling by combining metabolic screening, genetic engineering, and synthetic biology to construct bacterial strains capable of degrading and isolating synthetic polymers.Book of abstract: MikroBioKosmos Society & The Central and East Europe Symposium of Microbial Ecology (#mbkceesme2025), in Thessaloniki, Greece, between 22 and 24 September 2025

Outer membrane vesicles (OMVs) secreted by Paraburkholderia phytofirmans PsJN: characterization of associated RNA content and interaction with plant cells

Plant growth-promoting bacteria (PGPB) support plant development, increase productivity, and improve resilience to stress. These benefits arise from complex interactions between species, involving the exchange of various signaling and effector molecules. Extracellular vesicles (EVs) are an important means of signaling between cells, organisms, and even across biological kingdoms. Among EVs, outer membrane vesicles (OMVs)—produced by Gram-negative bacteria—can elicit both immune-activating and immune-suppressing responses in plants. However, direct interaction between OMVs and plant cell membranes has been shown for only a single phytopathogenic bacterial strain. Even less is known about the role of OMVs in symbiotic relationships between plants and beneficial bacteria, with existing data mostly limited to rhizobia-legume systems. To explore OMV-mediated interactions between non-rhizobial plant-beneficial bacteria and plant cells, we isolated and characterized OMVs from Paraburkholderia phytofirmans PsJN—a wellknown plant growth-promoting and stress-mitigating strain effective across various plant species. Using OMVs labeled with the fluorescent lipid-binding dye Vybrant™ DiD and visualization via confocal laser scanning microscopy, we demonstrated that PsJN-OMVs directly interact with the root hairs and epidermal cells of Arabidopsis thaliana and tomato. Using the membrane fusion probe octadecyl-rhodamine B chloride (R18), we confirmed that PsJN-OMVs can fuse with plant cell membranes. We examined the RNA content of PsJN-OMVs. The OMV-associated RNA, which was mostly sized up to 200 nt, was sequenced using the DNBSEQ Sequencing Platform. Prior to library synthesis, samples were separated into two subsamples: one up to 40 nt and the other from 40 to 200 nt. These were then sequenced using the SE50 and PE100 approaches, respectively. The same procedure was used for small RNA isolated from PsJN cells. Comparison of RNA sequences from PsJN OMVs and cells showed substantial differences in their size distribution, biotypes, and genome regions of origin. The results indicate that the packaging of RNA into PsJN-OMVs is not random, but involves the selective enrichment of certain RNA species in OMVs, while others are predominantly retained within the cells. Previous studies suggested that EVs may both remove unnecessary cellular RNAs and transfer RNAs to other cells, as signaling functions. The molecular mechanisms for selective loading of eukaryotic EVs are only partially described, while those responsible for bacterial vesicles are poorly understood. The data on RNA associated with OMVs secreted by plant beneficial bacteria are even more scarce. Our results make a significant step toward understanding the role of OMVs in the initial phases of root colonization and symbiosis establishment. Advancing knowledge in this field may lead to the development of innovative, environmentally friendly strategies to address agricultural challenges and promote sustainable crop production.Book of abstract: Arturo Falaschi Conference “Cell-cell communication in bacteria: new insights and future trends”, 28-30 October 2025 | Trieste, ITAL

Bacterial diversity analysis of glyphosate-exposed and pristine soil samples

Glyphosate is the active ingredient in widely used broad-spectrum herbicides, and its extensive application raises increasing concerns about environmental accumulation and ecological impact. It is known to be toxic to aquatic organisms, while numerous studies have also reported adverse effects on plant growth, insect gut microbiota, and human health. Therefore, research on soil bacterial communities can significantly contribute to the discovery of novel and effective strategies for the bioremediation of glyphosate-contaminated sites. In this study, metagenomic analysis based on 16S rRNA gene amplicons was performed on soil samples from an agricultural site with prolonged glyphosate exposure and a reference forest soil with no history of herbicide application. The bacterial composition of each sample was evaluated, revealing high overall microbial diversity. Actinobacteria and proteobacteria were the dominant phyla across all samples, while the relative abundance of other phyla varied depending on the sampling site. Marked differences were observed at the genus level, distinguishing the forest microbiome from those exposed to glyphosate. The presence of species and genera previously reported to degrade glyphosate was also examined. Functional profiling based on 16S rRNA amplicons predicted ABC transporters, glutathione S-transferases, and ECF RNA polymerase sigma-70 factors—proteins typically associated with stress response—as differentially abundant between samples. These findings provide insight into how chronic glyphosate exposure shapes soil microbial communities and their potential functional adaptations, highlighting microbial diversity as a valuable resource for developing sustainable bioremediation strategies for glyphosate-polluted environments.Book of abstract: 75th Panhellenic Conference of the Hellenic Society of Biochemistry and Molecular Biology (EEBMB Athens, December 5-7, 202

Salivary microbiome signatures of Poles and Serbians and its potential for prediction of biogeographic ancestry

Biogeographical ancestry analysis is valuable in forensic investigations, especially in missing person cases or crimes without eyewitnesses, as it helps to infer geographic origins from genetic markers. This approach enhances forensic efforts by providing essential clues for identifying individuals with limited direct evidence. Slavic-speaking populations are poorly distinguishable based on human genome variability. However, recent studies show that even populations with close biogeographic origin could be differentiated based on salivary microbiomes. Nevertheless, the salivary microbiomes of Slavs have not been characterized yet. Therefore, this study aimed to compare the composition of the salivary microbiomes of Western and Southern Slavs’ representatives. 16S rRNA libraries from salivary microbiomes of 40 Poles (Western Slavs) and 40 Serbians (Southern Slavs) were prepared via PCR and sequenced on the MiSeq FGx platform (Illumina), giving approximately 100,000 reads per sample. Bioinformatic and statistical analyses were performed to assess the alpha and beta diversity of microbiomes and determine the differences in the abundance of bacterial genera between the groups studied. Analyses of alpha (ACE, Chao1, Shannon, and Simpson) and beta (Jaccard and Bray-Curtis dissimilarity) diversities in the salivary microbiomes clearly distinguished between Poles and Serbians. Alpha and beta diversity metrics were significantly higher in the Serbian population. Fusobacterium, Lautropia, Porphyromonas, Actinobacillus, Capnocytophaga, and Kingella were the most significantly increased genera in Serbians, whereas Veillonella, Selenomonas, Megasphaera, and Atopobium were more prevalent in Poles. In summary, our study identified significant differences in the salivary microbiomes of Poles and Serbians, with distinct microbial signatures associated with each population. These findings highlight the potential of salivary microbiome analysis as a tool for predicting biogeographic ancestry. Nevertheless, further analysis extended to other Slavicspeaking populations is necessary to clarify this issue

Sustainable eco-friendly active packaging from food processing waste: Recycled starch and pomegranate peel extract for biodegradable solutions

Reducing plastic usage and improving food preservation are critical steps toward a more sustainable future, and converting food waste into eco-friendly food packaging offers a promising solution to both challenges [1]. Food packaging is essential for safeguarding food from spoilage and microbial growth, with active packaging technologies providing an effective means of extending shelf life. While plastic packaging is commonly chosen for its affordability and strong mechanical and barrier properties, its environmental persistence and limited biodegradability pose significant sustainability issues. In response, there has been growing interest in biopolymers as an alternative to synthetic plastics, offering both environmental benefits and the potential to retain desirable packaging qualities. This study focuses on developing advanced, sustainable food packaging materials derived from food processing waste. Specifically, recycled starch from potato chip factory waste and poly(vinyl alcohol) (PVA) were combined to create an active food packaging material. To enhance the packaging's functionality, pomegranate peel extract (PPE), typically discarded during fruit juice production, was incorporated for its natural antioxidant and antimicrobial properties. Additionally, in a fermentation process conducted in an 8-channel bioreactor, recycled starch served as a growth medium for Streptomyces anulatus BV365 producing actinomycin D (ActD)2, a bioactive compound with antimicrobial effects, to further boost the material’s effectiveness. The study produced several novel packaging materials with varying PPE concentrations (5% and 10%), along with a control sample without PPE, using glycerol as a plasticizer. The incorporation of PPE and ActD enhanced the packaging’s ability to extend food shelf life by imparting antioxidant and antimicrobial properties. Meanwhile, the starch-PVA blend, contributes to the biodegradability of the packaging. The materials were characterized using a range of analytical techniques, including Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), wettability and water contact angle (WCA) measurements. FTIR analysis confirmed the successful incorporation of PPE and ActD, while the addition of PPE improved the mechanical strength and swelling behavior of the starch-PVA based materials at both 5 and 10 wt% concentration. These findings demonstrate that the combination of enhanced functionality with environmental sustainability makes these bio-based packaging materials a promising alternative for reducing plastic waste while still preserving food quality.E-book: 19th International Conference on Chemistry and the Environment ICCE 2025 Belgrade 8-12 June 202

Development of Bioactive Cotton, Wool, and Silk Fabrics Functionalized with Origanum vulgare L. for Healthcare and Medical Applications: An In Vivo Study

Background: This study presents an innovative approach to developing bioactive natural fabrics for healthcare and medical applications. Methods: An ethanol extract of Origanum vulgare L. (in further text: OE), exhibiting exceptional antioxidant (100%) and antibacterial activity (>99% against E.coli and S.aureus), was employed to biofunctionalize cotton, wool, and silk fabrics. Results: All biofunctionalized fabrics demonstrated strong antioxidant activity (>99%), while antibacterial efficacy varied by fabric: cotton > 54%, wool > 99%, and silk > 89%. OE-biofunctionalized wool possessed the highest release of OE’s bioactive compounds, followed by silk and cotton, indicating substrate-dependent release behavior. This tunable fabrics’ OE release profile, along with their unique bioactivity, supports targeted applications: OE-functionalized silk for luxury or prolonged therapeutic use (skin-care textiles, post-surgical dressings, anti-aging products), cotton for disposable or short-term use (protective wipes, minor wound coverings), and wool for wound dressings. The biocompatibility and cytotoxicity of OE-biofunctionalized wool were evaluated via in vitro assays using healthy human keratinocytes and in vivo testing in Wistar albino male rats. The obtained results revealed that OE-functionalized wool significantly accelerated wound closure (97.8% by day 14), enhanced collagen synthesis (6.92 µg/mg hydroxyproline), and improved tissue and systemic antioxidant defense while reducing oxidative stress markers in skin and blood samples of rats treated with OE-biofunctionalized wool. Conclusions: OE-biofunctionalized wool demonstrates strong potential as an advanced natural solution for managing chronic wounds. Further clinical validation is recommended to confirm its performance in real-world healthcare settings. This work introduces an entirely new application of OE in textile biofunctionalization, offering alternatives for healthcare and medical textiles

Degradation of Synthetic and Natural Textile Materials Using Streptomyces Strains: Model Compost and Genome Exploration for Potential Plastic-Degrading Enzymes

Given the environmental significance of the textile industry, especially the accumulation of nondegradable materials, there is extensive development of greener approaches to fabric waste management. Here, we investigated the biodegradation potential of three Streptomyces strains in model compost on polyamide (PA) and polyamide-elastane (PA-EA) as synthetic, and on cotton (CO) as natural textile materials. Weight change of the materials was followed, while Fourier-Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were used to analyze surface changes of the materials upon biodegradation. The bioluminescence-based toxicity test employing Aliivibrio fischeri confirmed the ecological safety of the tested textiles. After 12 months, the increase of 10 and 16% weight loss, of PA-EA and PA, respectively, was observed in compost augmented with Streptomyces sp. BPS43. Additionally, a 14% increase in cotton degradation was recorded after 2 months in compost augmented with Streptomyces sp. NP10. Genome exploration of the strains was carried out for potential plastic-degrading enzymes. It highlighted BPS43 as the most versatile strain with specific amidases that show sequence identity to UMG-SP-1, UMG-SP-2, and UMG-SP-3 (polyurethane degrading enzymes identified from compost metagenome). Our results showcase the behavior of Streptomyces sp. BPS43 in the degradation of PA and PA-EA textiles in composting conditions, with enzymatic potential that could be further characterized and optimized for increased synthetic textile degradation

Diversity and biotechnological potential of cultivable alkaline aquatic microbiomes

Water samples, originating from the mildly alkaline (pH 7.4) brackish groundwater spring (MAGW), moderately alkaline (pH 8.1) hypersaline sea (SW), and fresh lake (LW), as well as from the hyperalkaline (pH 11.7) fresh groundwater well (HAGW), were selected to examine the diversity of cultivable bacteria and to assess their plastolytic and lignocellulolytic potential. The most represented aquatic genera after cultivation were Aeromonas in LW and MAGW sample, Bacillus in HAGW sample, and Vibrio in SW sample. Over 60% of 128 screened aquatic isolates had the ability to grow on plastic substrates Impranil® DLN-SD (SD) and DL 2077, polycaprolactone diol, and bis(2-hydroxyethyl) terephthalate as sole carbon source, while 8.6% of screened isolates showed signs of polyurethane degradation. Majority (>90%) of all screened isolates grew on lignocellulosic substrates carboxymethyl cellulose, xylan, and lignin, respectively, while 12.5% of screened isolates, all originating from the examined groundwater samples, demonstrated complete degradation of cellulose. Potential applications of polyurethane- and cellulose-degrading microbial isolates for the management and valorization of plastic and biomass waste in aquatic environments should be further explored. Practitioner Points Vibrio, Aeromonas, and Bacillus were the most represented genera after seawater, lakewater, and groundwater cultivation. Over 60% of all screened aquatic isolates grew on four tested plastic substrates, with 8.6% showing signs of polyurethane degradation. Majority of screened aquatic isolates grew on three tested lignocellulosic substrates, with 12.5% completely degrading carboxymethyl cellulose. Biotechnological potential of polyurethane- and cellulose-degrading isolates for plastic and biomass waste management in aquatic environments should be further explored