BIOREpository (Faculty of Biology, University of Belgrade)
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Targeting Gram-Negative Bacterial Biofilm with Innovative Therapies: Communication Silencing Strategies
No full textBiofilm-associated infections caused by Gram-negative bacteria, especially multidrug-resistant strains, frequently occur in intensive care units and represent a major therapeutic challenge. The economic burden of biofilm-associated infections is considerable, making the search for new treatment approaches a focal point for policymakers and scientific funding bodies. Biofilm formation is regulated by quorum sensing (QS), a population density-dependent communication mechanism between cells mediated by small diffusible signaling molecules. QS modulates various intracellular processes, and some features of QS are common to all Gram-negative bacteria. While there are differences in the QS regulatory networks of different Gram-negative bacterial species, a common feature of most Gram-negative bacteria is the ability of N-acylhomoserine lactones (AHL) as inducers to diffuse across the bacterial membrane and interact with receptors located either in the cytoplasm or on the inner membrane. Targeting QS by inhibiting the synthesis, transport, or perception of signaling molecules using small molecules, quorum quenching enzymes, antibodies, combinatorial therapies, or nanoparticles is a promising strategy to combat virulence. In-depth knowledge of biofilm biology, antibiotic susceptibility, and penetration mechanisms, as well as a deep understanding of anti-QS agents, will contribute to the development of antimicrobial therapies to combat biofilm infections. Advancing antimicrobial therapies against biofilm infections requires a deep understanding of biofilm biology, antibiotic susceptibility, penetration mechanisms, and anti-QS strategies. This can be achieved through in vivo and clinical studies, supported by state-of-the-art tools such as machine learning and artificial intelligence.M222,7355
Screening of phenolics content and antioxidant properties of 27 extracts from traditional pear fruits
No full textBook of abstracts 136M3
Molecular detection od Echinococcus spp. in hunting dogs
No full textEchinococcosis is a zoonotic parasitic disease caused by tapeworms of the genus Echinococcus.Definitive hosts are foxes, jackals, dogs, and less often cats, while intermediate hosts arecommonly rodents. Humans and other mammals are accidental hosts. Wild carnivores play a keyrole in dispersing tapeworm eggs in the environment, yet domestic species can contribute totransmission of tapeworms to humans. Echinococcus multilocularis has been detected in goldenjackals in eastern Serbia, south of the Danube. The larval stage of this species causes alveolarechinococcosis, characterized by invasive, infiltrative growth, akin to malignant neoplasms. In thisstudy, feces of hunting dogs (n=30) from the same region were analyzed for the presence ofEchinococcus spp. A questionnaire was administered to owners to determine husbandry practicesand use of antihelminthics. Taeniid eggs (22-50 μm) were isolated from feces using ZnCl2 flotationcombined with mesh filtration, followed by DNA (deoxyribonucleic acid) isolation and PCR(polymerase chain reaction) analysis for the identification of Echinococcus granulosus,Echinococcus canadensis and Echinococcus multilocularis. No Echinococcus spp. eggs weredetected. Questionnaire results showed that most hunting dogs reside in rural areas, are keptoutdoors and are taken to hunting grounds, but regular deworming is not practiced. These findings,along with the presence of Echinococcus multilocularis in jackals, suggest that there is a risk forinfection of dogs and transmission to humans. Additional research to identify infected dogs isongoing. The role of veterinarians in promoting the importance of regular deworming of huntingdogs is vital, to implement effective prevention, similar to the rabies model.M3
Key findings on large branchiopods from the threatened Bardača Wetland Ramsar site and surrounding areas in Bosnia and Herzegovina
No full textStudies on large branchiopods, crustaceans that inhabit temporary waters in Bosnia and Herzegovina, are relatively rare. Recently published data from the Ramsar site “Bardača Wetland” and the neighboring area of Donja Dolina revealed the presence of nine species. The nine-year study included the investigation of environmental gradients in regularly flooded and non-flooded areas where species occur, including 28 ephemeral sites. The ordination of environmental factors, species and samples on the space defining the first two CCA axes, as well as post-hoc test analyses, confirmed a significant influence of inundation. Conductivity, temperature and oxygen are the most important factors for species distribution. The temperature and oxygen values were independent of each other in the ordination. The position of species on the CCA axes revealed different patterns and in some cases was dominated by a single variable—conductivity (e.g. Lepidurus apus, and Cyzicus sp.), while most of branchiopod taxa occupied a lower portion in the ordination. Cluster analysis of the different taxa and localities revealed a complex pattern. In most cases, there was no clear subdivision between sites and species in terms of flooding. However, some species were clearly dependent on rainfall and groundwater (Eubranchipus. (S.) grubii, Linderiella sp. and Triops cancriformis), others exclusively on flood waters (L. apus).M221.
Toxoplasma gondii infection in the golden jackal (Canis aureus)
No full textSerbia hosts one of the largest resident populations of golden jackals (Canis aureus) in Europe. This species is known for its adaptability to different habitats, opportunistic feeding behaviour and flexible social organisation, which contribute to its role as a host for a wide range of parasite species. Given its distribution across the entire country, the jackal serves as an excellent sentinel for Toxoplasma gondii in various environments. To explore this potential and the distribution of the parasite, total DNA was extracted from the heart apex of legally hunted jackals, collected during 2023 and 2024. Heart samples from 75 jackals were analysed, of which 36 individuals came from the wider Belgrade (capital) area. Real-time PCR was performed to detect the parasite targeting the 529 bp repetitive element in the T. gondii genome. Overall, 40% of the animals (n=30) examined were found to be infected with T. gondii. Notably, infection prevalence was higher in jackals from the Belgrade area (44.4%) compared to those from other areas (35.9%). These findings suggest greater environmental exposure to the parasite in urban and peri-urban settings, raising potential public health concerns. Ongoing work includes expanding the sample size to cover different habitats within the jackal distribution in Serbia and the processing of archived samples. Genotyping of T. gondii isolates using microsatellite markers will be conducted on positive samples to further investigate the genetic diversity of this parasite among jackals in Serbia.M3
Plant-growth-promoting potential of bacteria from organic and chemically-treated red raspberry roots and rhizosphere
No full textAbstract book, 1439M3
High Level Fluoroquinolone Resistance and Multidrug Resistance in Salmonella Spp. Isolated from Poultry, Turkey Floks and Slaughterhouses in Algeria
No full textIn this work, Salmonella spp. was detected in poultry and turkey farms, slaughterhouses and hatcheries in the Sétif Province in Algeria. Eighty single isolates per farm were analyzed by establishing the resistotype and detected resistance genes underlining the mechanism of resistance. In one case, serotypes S. Virchow and S. Ivory were found in the same sample and both isolates were resistant to nalidixic acid. S. Enteritidis was detected in four broiler breeder flocks, three hatcheries, 12 flocks of layers, 12 broiler flocks while five slaughterhouses yielded 10 isolates. The wide distribution of S. Enteritidis in the primary production and food chain in Algeria requires special measures in the management practice on poultry farms. All isolates except five were resistant to nalidixic acid and pefloxacin which means that these salmonellae phenotypically express reduced sensitivity to ciprofloxacin. Five isolates were multidrug resistant. Two Salmonella Galinarum biotype gallinarum isolates from flocks of laying hens were resistant to quinolones, aminoglycosides and sulfonamides. One of these isolates was also resistant to trimethoprim alone and in combination with sulafmethoxazole. One S. Enteritidis isolate was resistant to ampicillin, nalidixic acid, pefloxacin and colistin. Especially worrying is the high level of resistance to ciprofloxacin in nine isolates (six, Salmonella Galinarum biotype gallinarum, two, S. Kentucky and one Salmonella enterica subsp. enterica isolate) due to mutations in the enzymes DNA gyrase and topoisomerase IV. Resistance genes were identified in 21 isolates. All resistance genes detected are commonly conferring resistance to ampicillin, streptomycin, gentamicin, tetracycline, sulfonamides and trimethoprim antibiotics.M220,830932575
Macerated plant extracts as a sustainable alternative for corrosion protection of aluminium in chloride environment
No full textThis study comprises the extraction and characterisation of plant extracts derived from (i) Thymus serpyllum, (ii) Ocimum basilicum, and (iii) Satureja montana. Extracts were prepared by a maceration process using three solvents: distilled water, ethanol, and a water-ethanol mixture. Phytochemical analysis revealed significant variations in total phenolic, flavonoid, triterpenoid, and coumarin contents, with optimal extraction conditions differing among plant species and solvents used for extraction. First, the antimicrobial activity of extracts was investigated. Extracts selectively inhibited Staphylococcus aureus growth but not Pseudomonas aeruginosa. Then, an electrochemical investigation was conducted to assess the potential of plant extracts as corrosion inhibitors for aluminium in 0.1 M NaCl solution. S. montana water extract exhibited the most promising corrosion protection. Long-term immersion tests measured by electrochemical impedance spectroscopy and potentiodynamic polarisation showed that S. montana extracts enhanced aluminium’s resistance to corrosion over time, seen as an increase in impedance magnitude and a broader passivity region. Surface characterisation via scanning electron microscopy and Fourier-transform infrared spectroscopy confirmed the adsorption of phytochemicals and formation of a protective layer on the aluminium surface. This study is the first to demonstrate the significant corrosion inhibition effect of S. montana extracts on aluminium, highlighting its potential as a sustainable
alternative for corrosion protection.M215.614758554
Disentangling the Effects of Suicide Attempts and Psychiatric Diagnosis Based on a Genotype-Informed Dynamic Model of the Serotonin Presynapse
No full textBackground: Suicide attempts often co-occur with bipolar disorder (BD), major depressive disorder (MDD), and schizophrenia (SCH). Although impairments of the serotonin (5-HT) system have been associated with suicide attempts, it remains unclear whether these alterations reflect suicidal behavior or are confounded by underlying psychiatric diagnosis. This study used a genotype-informed dynamic model of the 5-HT presynapse to disentangle the effects of suicide attempts and psychiatric diagnosis. Methods: We applied a personalized dynamic model of the 5-HT presynapse to 392 psychiatric patients (with BD, MDD, or SCH), categorized by suicide attempt status, and 140 unaffected individuals. The model incorporated five variants across TPH2, SLC6A4, and MAOA genes simulating individual-specific concentration changes of five 5-HT-related molecular species. Model outputs were summarized by six statistical measures (mean, median, maximum, standard deviation, skewness, and kurtosis) and compared across groups. Results: No significant differences were found across groups defined by suicide attempt status and unaffected individuals. However, diagnosis significantly influenced 5-hydroxyindoleacetic acid (5-HIAA) mean, median, maximum, and standard deviation (all p < 0.05). BD patients had lower 5-HIAA levels than SCH patients (mean: p = 0.013; median: p = 0.013; maximum: p = 0.014; standard deviation: p = 0.014). MDD patients also showed lower 5-HIAA levels than SCH patients for the same measures, with differences approaching significance. No significant difference was observed between BD and MDD patients. A diagnosis-by-suicide attempt status interaction was observed for 5-HIAA skewness (p = 0.013). Conclusions: Model-derived 5-HT profiles were shaped primarily by diagnosis, while temporal dynamics of 5-HIAA, rather than its absolute levels, was associated with suicide attempt status. Thus, personalized dynamic modeling incorporating genetic variants may aid in detecting subtle molecular signatures across diagnoses and suicidal behavior.M223.31141161
