Phenolicsandcellwallremodellingin fruits of tomatooverexpressing GGP1gene

Tomato fruit ripening involves complex physiological processes, including the biosynthesis and degradation of cell wall components such as polysaccharides, phenolics, and proteoglycans, leading to fruit softening. In this study, we investigated how the overexpression of GDP-Lgalactose phosphorylase (GGP1)– a key gene in the Lgalactose-dependent ascorbate (Asc) biosynthesis pathway- under the control of two fruit-specific promoters, namely PPC- phosphoenolpyruvate carboxylase and PG– polygalacturonase, influences cell wall properties and phenolic profile. It was shown that GGP1 overexpression increases Asc content in ripening tomato fruit and upregulates genes associated with cell wall remodelling [1]. Here, we demonstrated that PPC-GGP1 and PG-GGP1 transgenic lines exhibited significant structural alterations in the fruit parenchyma compared to wild-type fruits, particularly a disruption of cell wall composition and organisation [2]. These included modifications in spatial distribution and chemical composition of homogalacturonans and arabinogalactans, as well as changes in the pectin methylation degree. Alongside with reduced content of free chalconaringenin, p-coumaric and protocatechuic acids, the amount of cell wall-bound p-coumaric acid and the corresponding monolignol, p-coumaryl alcohol, was higher in the transgenic fruits. These findings highlight a metabolic interplay between Asc biosynthesis and cell wall remodelling, with potential implications for postharvest fruit quality and storage.Programme and Book of Abstracts 25-28 JUNE 2025, Budapes

The role of the Notch signaling pathway in rhabdomyosarcomas

Rhabdomyosarcoma (RMS) is a pediatric soft tissue cancer with poor prognosis in cases of metastasis. Different signal transduction pathways have been studied in RMS cells as to shed some light into the tumorigenesis and metastasis mechanisms of this cancer in the search for new diagnostic and therapeutic strategies. The Notch pathway, which regulates cell survival, is widely studied in different cancers, including sarcomas and its activation has been known to induce cell motility. To this end, the present review explores the role of the Notch signaling pathway in the progression of RMS and in potential therapeutic strategies

Structural Properties of Intrinsically Disordered Dehydrins Underlying Their Protective Role in Desiccation Tolerance

Drought is a major threat to global food security, presenting a critical challenge for agriculture. Resurrection plants exhibit extraordinary desiccation tolerance, surviving the loss of up to 98 % of their water content for extended periods and fully recovering metabolic function upon rehydration. Investigating the molecular mechanisms underlying this adaptation can offer valuable insights for enhancing crop resilience to drought. Dehydrins, a subclass of late embryogenesis abundant (LEA) proteins, accumulate in resurrection plant leaves during desiccation. Although they have been implicated in the protection of proteins, membranes, and nucleic acids, their precise physiological function remains unknown. In this study, we recombinantly produced DHN152, a desiccation-induced dehydrin from Ramonda serbica, an ancient resurrection species, and analysed its structural and functional properties. DHN152 is a highly hydrophilic protein (GRAVY index: –1.29) with a high glycine content (22.6%) and abundant charged residues (lysine, glutamate, and aspartate). In silico analyses of DHN152 revealed high disorder propensity, which was confirmed by circular dichroism (CD) spectroscopy under physiological conditions. Upon exposure to 2,2,2-trifluoroethanol (a desiccation-mimicking agent) and lipid-mimetic detergents, DHN152 partially adopted an α-helical conformation, highlighting its structural plasticity. Given its lysine- rich composition and predicted nuclear localisation, we examined its effect on DNA under desiccation conditions. Additionally, we assessed its protective effects on enzyme activity and Escherichia coli growth under osmotic and salt stress. Taken together, our findings provide novel insights into the structure- function relationship of dehydrins in resurrection plants, laying the groundwork for bioengineering strategies aimed at improving drought resistance in crops.Book of abstract: 15th EBSA Congress in Rome, Italy, from the 30th of June to the 4th of July 2025

Eriodictyol and Diosmetin Protective Potential in Skin Infection: Antimicrobial Action, Gene and Molecular Targets, and Keratinocyte Protection Against Bacteria-Induced Damage

Eriodictyol and diosmetin are bioactive flavonoids. This study explored their antimicrobial activities and antibiofilm potential along with the effect on pyocyanin and protease production and virulence-linked gene expression, followed by in silico molecular target predictions. Moreover, keratinocytes were used for the evaluation of cytotoxicity and protective antioxidant and anti-inflammatory effects in the infected cells. Both compounds have shown significant antibacterial capacity towards skin pathogens (minimal inhibitory concentrations 0.025–0.2 mg/mL). Their ability to prevent biofilm formation of Pseudomonas aeruginosa was drastic, as well as the impact on other virulence factors, proteases, and pyocyanin production. RT-qPCR determined downregulation of almost all genes examined (lasI, lasR, lasB, rhlI, rhlR, rhlC, pqsH, pqsR, pvdS, pvdF, phzM, and algK), while molecular docking predicted strong binding affinities to the LasI, LasR, PqsR, and QscR quorum-sensing proteins. Moreover, both compounds were not toxic to HaCaT and were able to reduce damage induced by P. aeruginosa in this cell line. Precisely, eriodictyol reduced levels of secreted IL-6 (from 335.32 to 261.76 pg), while both compounds reduced the formation of superoxide. Both eriodictyol and diosmetin displayed remarkable antimicrobial potential while employing a wide array of antimicrobial mechanisms, making them attractive candidates for further assessment and eventual incorporation into novel therapeutic strategies

A Novel ST1 Lactonase Reduces Virulence and Inhibits Biofilm Forma=on and Extends the Lifespan of Caenorhabdi9s elegans Infected with Pseudomonas aeruginosa MMA83

Background: Bacterial biofilms represent a major challenge in clinical seNngs due to their resistance to an3bio3cs and immune responses. Pseudomonas aeruginosa is a significant opportunis3c pathogen responsible for chronic infec3ons, par3cularly in immunocompromised pa3ents. Quorum quenching (QQ) enzymes, such as lactonases, show promise in disrup3ng biofilm forma3on and reducing bacterial virulence. This study examines the effects of ST1-YtnP lactonase from thermophilic Bacillus licheniformis on biofilm forma3on and virulence of P. aeruginosa MMA83. Methods: The an3biofilm effect of recombinant ST1-YtnP lactonase on mul3-drug resistant P. aeruginosa MMA83 was analyzed using fluorescence microscopy. CaenorhabdiLs elegans infec3on model was used to evaluate the enzyme’s effect on virulence and host survival. The liquid killing assay was employed using the C. elegans AU37 mutant strain to quan3ta3vely evaluate host survival in response to ST1-YtnP lactonase treatment. Results: Fluorescence microscopy showed a significant reduc3on in P. aeruginosa MMA83 biofilm forma3on with ST1-YtnP lactonase, leading to a looser, less dense biofilm. Planktonic cell growth remained unaffected. In C. elegans, treatment resulted in an almost 100% survival rate, while untreated infected worms showed 0% survival within 24 hours. ST1-YtnP lactonase exhibited no toxicity, consistent with previous studies on QQ enzyme safety in eukaryo3c models. Conclusion: ST1-YtnP lactonase inhibits P. aeruginosa MMA83 biofilm forma3on and reduces virulence in C. elegans, indica3ng its poten3al as a safe and effec3ve an3virulence agent for biomedical applica3ons.Book of abstract: BIOFILMS 11, 13 – 15 May 2025, Mercure Cardiff Holland House Hotel & Spa, Cardiff, U

Upcycling PET plastic waste into bacterial nanocellulose based electro catalyst efficient in direct methanol fuel cells

Bio-upcycling is an emerging end-of-life strategy for the polymer waste treatment that uses the power of microorganisms to biocatalyticaly convert the pre-treated polymer waste monomers into high-added materials. Poly(ethylene terephthalate) (PET), one of the leading synthetic polyesters in the global polymer market, produced from petrol based feedstock, still has no completely green alternative to meet global demand. Therefore, putting the PET based waste into a circular loop has become one of the major challenges of plastic waste management. In that context, the present study addressed the conversion of PET containing hydrolysates collected after the thermal pretreatment into bacterial nanocellulose (BNC), nowadays one of the most promising biopolymers produced in a sustainable manner. After the optimization of the BNC production cultivated under different conditions in PET hydrolysates, in a static way, the optimal conditions (yield of 3.0 mg/ml) was applied for scaling up. To further open the applicative potential of the BNC produced from PET containing plastic waste, platinum nanoparticles were deposited onto BNC developing new catalyst active in the methanol oxidation reaction. In order to enhance BNC ability to support Pt nanoparticles, it was blended with poly(vinyl alcohol), PVA, producing new PVA/BNC composites, recognized as an improved solid support, rich in hydroxyl groups that serve as an anchor points to Pt deposition. Due to the enrichment of BNC by PVA, it was possible to prepare highly active Pt-based catalyst with only 3 wt% of loaded Pt, which significantly reduce the cost of catalyst production. The cost-effective catalyst was prepared using sodium boron hydride as a reducing agent associated with film casting and fully characterized using FTIR, TGA, XRD, XPS, TEM, SEM-EDX analysis and its potential was confirmed in methanol oxidation reaction. This study explored the circular pathway from PET plastic waste to BNC and further to its potential application in direct methanol fuel cell (DMFC)

Airborne Pathogens and Virulence Factors in Belgrade Metropolitan Area Metagenomic Insight

Introduction: Air pollution has been recognized as one of the greatest threats to human health. The particulate matter-PM2.5, main air pollution indicator, is found to contain numerous bacterial pathogens. Considering that Serbia is struggling with excessive antibiotics use and misuse, a high percentage of multidrug-resistant (MDR) bacterial isolates, and poor air quality, made Serbian capital Belgrade interesting research model for the effects of air pollution on the abundance and diversity of airborne pathogens. Objective: The presence of MDR pathogens, virulence factors as well as pathogen-host interactions are studied in the airborne metagenome samples from seven locations of Belgrade metropolitan area collected during the summer season of 2024. Method: Air samples were collected from seven Belgrade locations using hydrophobic polypropylene membrane filters (air volume of 30 m³). Total DNA was analysed by shotgun metagenomic sequencing, followed by bioinformatic processing (Novogene, UK). Taxonomic diversity/abundance, virulence factors and pathogen-host interactions were analysed using MEGAN, VFDB, and PHI databases, respectively. Findings: Important human and animal pathogens were found in analysed metagenomes: Acinetobacter schindleri, Streptococcus pneumonie, Streptococcus oralis, Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumoniae, Ewingella americana, Burkholderia multivorans, Legionella pneumophila, Salmonella enterica and Brachybacterium muris. Genes encoding for motility, adherence, immune modulation, exotoxins and biofilm formation were also found. Additionally, PHI analysis revealed the presence of different type of infections caused by pathogenic bacteria – nosocomial and urinary tract infections, pneumonia, salmonellosis, soft rot. Conclusion: This study indicated that Belgrade air could serve as a reservoir for pathogenic bacteria, virulome and numerous types of infections.Book of abstract: FEMS MICRO 2025: Congress & Exhibition, taking place in Milan, Italy, from 14-17 July 2025

Establishing transgenic zebrafish model expressing the A30P α-synuclein mutation for Parkinson’s disease research

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder worldwide. Major characteristic of PD is the pathological aggregation of α-synuclein protein in the brain. Among the inherited α-synuclein mutations, associated with PD, the A30P mutation is known to stimulate the formation of toxic oligomers and fibrils. To better understand the molecular mechanisms underlying PD and to promote the development of novel therapies, animal models, such as zebrafish, expressing human α-synuclein variants are used. Our study aimed to establish a new transgenic zebrafish model expressing mutated the A30P α-synuclein, facilitating in vivo investigation of the mechanisms of early aggregation processes. Here we present a generation of new transgenic zebrafish line stably overexpressing human αsynuclein with amino acid substitution A30P. The plasmid UAS:Dendra2-Hsa.SNCA, myl7:EGFP, coding for human α-synuclein tagged with Dendra2 as well as a transgenesis marker expressing EGFP under a heart-specific promoter, was used as a template for site-directed mutagenesis. Tol2 transgenesis system was composed of the A30P plasmid (UAS:Dendra2Hsa.SNCA_A30P, myl7:EGFP) and Tol2 RNA. They were microinjected into embryos at one-cell stage and embryos were screened three days post fertilization for EGFP-positive signal in the heart. EGFP-positive larvae are raising to adulthood, to identify carriers. Once the animals reach sexual maturity, outcrosses with the pan-neuronal driver line PanN:GAL4, will enable targeted expression of the mutated α-synuclein in the nervous system, facilitating future studies on oligomer-induced neurotoxicity relevant to PD pathogenesis and allowing for testing of potential new treatments.BeCELS 2025: Belgrade Conference for Early-Career Life Scientists, taking place on Friday, September 5, 2025, at the Institute of Molecular Genetics and Genetic Engineering (IMGGE) in Belgrad

24 Correlation between the expression of proinflammatory cytokine genes and immunomodulatory microRNAs miR-27a, miR-222 and miR-340 in peripheral blood mononuclear cells of women with gestational diabetes

Continuous low-level inflammation (IFM) is a major contributory factor to development of severe pregnancy complications associated with gestational diabetes mellitus (GDM). Presence of IFM throughout the hyperglycemic pregnancy associates with disturbances in microRNA-related mechanisms, while inflammatory pathway-related genes are known targets of microRNAs dysregulated in GDM. Our aim was to evaluate the correlation between the expression of GDMrelated microRNAs (miR-27a, miR-222 and miR-340) and mRNA encoding proinflammatory cytokines IL-1β, IL-8, TNFα and IL6 in peripheral blood mononuclear cells (PBMCs) from women with GDM and healthy controls. PBMCs were isolated from blood samples during pregnancy weeks 24-30 (n=50 per group). Relative quantification of relevant microRNAs and mRNAs was conducted by quantitative real-time PCR, while Pearson correlation test was used for statistical evaluation of the obtained results. The expression of all three selected microRNAs showed negative correlation with the level of IL-8 and TNFα mRNA in PBMCs of GDM patients (negative r ranging 0.318–0.375), while such findings lacked for the control group. Additionally, miR-340 demonstrated correlation with the expression of IL-1β (r=-0.333). None of the microRNAs correlated with the expression of IL-6, which was the only mRNA with a statistically significant upregulation in GDM, compared to controls. The presented results illustrate the relation between the dysregulation of GDM-associated microRNAs and the expression of immune system modulators in GDM. The direction of correlation was negative and in accordance with the hypothesised regulatory mechanisms. Additional findings on circulatory levels of proinflammatory cytokines are required for further interpretation of IFM-related properties of selected microRNAs.BeCELS 2025: Belgrade Conference for Early-Career Life Scientists, taking place on Friday, September 5, 2025, at the Institute of Molecular Genetics and Genetic Engineering (IMGGE) in Belgrad

The K77 capsular polysaccharides as determinants of virulence and resistance in hypermucoid clinical isolate Acinetobacter baumannii 10593

Acinetobacter baumannii is an opportunistic pathogen and a major cause of hospital-acquired infections worldwide, with intrinsic antibiotic resistance and remarkable desiccation tolerance. Important virulence factor is the polysaccharide capsule which protects the bacteria from environmental stressors, including antimicrobials and the host immune response. With limited treatment options, capsular polysaccharides have become promising vaccine targets. To investigate the biological role and function of the capsule, the clinical isolate A. baumannii 10593, characterized by a hypermucoid phenotype, was selected from the laboratory’s collection. The capsule biosynthesis genes are clustered in the K locus. Following whole genome sequencing of the selected isolate, the KAPTIVE tool was used to analyse the K locus type, which was identified as KL77. Subsequently, the galU gene, involved in the biosynthesis of simple sugars, was selected for mutagenesis, and a corresponding knockout strain was successfully generated. The outcome of the selected gene deletion was assessed by comparing biofilm production between the wild type and the mutant strain using fluorescence microscopy, with the mutant showing a higher ability to form biofilm. The constructed deletion mutant was further employed to investigate the role of the capsule in several key aspects of A. baumannii pathogenicity, including antimicrobial resistance and tolerance to disinfectants. The knockout strain showed increased susceptibility to all tested disinfectants (benzalkonium chloride, benzethonium chloride, and chlorhexidine digluconate) and most antibiotics used in this study (meropenem, ciprofloxacin, gentamicin, amikacin, tobramycin, and colistin). Adhesion to extracellular matrix proteins (collagen type I and fibronectin) was examined and it was demonstrated that the mutant was able to adhere more strongly to these proteins compared to the wild type. Furthermore, LDH cytotoxicity assay using human keratinocyte line (HaCaT) showed that the mutant strain was less cytotoxic and therefore less virulent towards host cells than the wild type strain. Based on these findings, the K77 capsular polysaccharides play a significant role in the pathogenicity of A. baumannii 10593, as they enhance resistance to antimicrobials and disinfectants as well as cytotoxicity, whereas their disruption promotes bacterial adhesion.Book of abstract:6 BALKAN CONFERENCE ON BIOSCIENCES 30-31 OCT 2025 PLOVDIV, BULGARI