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Novel Pyridine-Based Thiazolyl-Hydrazone as a Promising Attenuator of Pseudomonas aeruginosa Pathogenicity by Targeting Quorum Sensing
No full textPseudomonas aeruginosa biofilm-associated infections present higher recalcitrance to antimicrobial treatments, contributing to persistent and difficult-to-treat infections. Quorum sensing (QS) regulates various cellular processes that are important for the establishment and survival of microbial communities on the host. However, QS inhibitors for the treatment of P. aeruginosa biofilms remain under-researched, partly due to the complexity of QS signalling pathways and the challenge of developing non-toxic inhibitors. Herein, the bioactivity of 2-{(2E)-2-[1-(pyridin-2-yl)ethylidene]hydrazinyl}-1,3-thiazole-4-carboxylic acid (TTNF37), a novel pyridine-based thiazolyl-hydrazone (PTH), was investigated. The compound antimicrobial activity was evaluated against a broad spectrum of microorganisms, its antioxidant potential was assessed using different assays, and its QS-inhibitory effect on P. aeruginosa was studied using bioreporter strains. The effect on P. aeruginosa biofilm formation was analysed in terms of biomass, culturability, and metabolic activity, structure, and cell membrane integrity, while virulence factors were evaluated through absorbance measurements. In addition, molecular docking studies were performed to predict the drug’s interactions with essential QS proteins and biological targets. TTNF37 exhibited potent antimicrobial activity with low to moderate minimum inhibitory concentrations against clinically relevant Gram-negative and Gram-positive bacteria, as well as fungi and yeasts. It also showed antioxidant activity, with variable effectiveness across different radicals and systems. TTNF37 inhibited the 3-oxo-C12-HSL-dependent QS system of P. aeruginosa in a dose-dependent manner, with reductions ranging from 26% to 98%. It also impaired the production and detection of 3-oxo-C12-HSL, resulting in a 56% and 65% decrease in bioluminescence, respectively. Molecular docking studies revealed strong binding interactions with LasI and LasR proteins, with affinity values exceeding those of furvina, a known potent QS inhibitor. Molecular dynamics simulations validated stable TTNF37 binding to LasR and LasI. Both experimental and docking data indicate a significant interaction with human serum albumin (HSA). TTNF37 also significantly reduced pyocyanin production and prevented biofilm set-up with a reduction of 50% in biomass with pronounced alterations in biofilm structure. These results indicate the potential of TTNF37 and related PTHs for treating biofilm-associated infections
Виртуелне лабораторије као средство за унапређивање разумевања фундаменталних хемијских концепата код ученика основних школа
No full textPrevious research indicates that laboratory experimentation is considerably
more effective than traditional receptive teaching in promoting the development
of elementary school pupils’ understanding of fundamental chemistry concepts.
Thus, for elementary schools that do not have a chemical laboratory, the use of
virtual laboratories that are freely available from numerous educational websites
was recommended. To compare the impact of virtual laboratory experimentation
and traditional receptive teaching on the development of elementary school pupils’
understanding of fundamental chemistry concepts, a pedagogical experiment
with parallel groups was conducted. The experiment was organized within the
elaboration of the teaching topic Solutions, and it included 137 seventh-grade
pupils (70 pupils in the experimental and 67 pupils in the control group). To assess
the pupils’ understanding of the composition and preparation of solutions, a test
comprised of six open-ended questions was used. The pre-testing showed that none
of the pupils had previous knowledge related to this content. However, on the posttest,
the experimental group archived a significantly higher overall percentage of
correct answers (t (135) = 2.105, p = 0.037), which implies that virtual laboratories
are highly effective in enhancing elementary school pupils’ understanding of
fundamental chemistry concepts.Претходна истраживања указују да je експериментални лаборато-
ријски рад далеко ефективнији од традиционалне рецептивне наставе у
погледу подстицања развоја разумевања фундаменталних хемијских конце-
пата код ученика основних школа. Последично, основним школама које не-
мају хемијску лабораторију препоручено је коришћење виртуелних лабора-
торија, које су бесплатно доступне на бројним образовним веб-сајтовима.
Ради поређења утицаја експерименталног рада у виртуелним лабораторијама
и традиционалне рецептивне наставе на развој разумевања фундаменталних
хемијских концепата код ученика основних школа, спроведен је педагошки
експеримент са паралелним групама. Експеримент је организован у оквиру
обраде наставне теме Раствори и у њему је учествовало 137 ученика седмог
разреда (70 ученика у експерименталној и 67 ученика у контролној групи).
За проверу ученичког разумевања састава и припреме раствора коришћен је
тест који се састојао из шест питања отвореног типа. Иницијално тестирање
је показало да нико од ученика није поседовао предзнања везана за помену-
те наставне садржаје. Међутим, на завршном тесту, ученици из експеримен-
талне групе остварили су статистички значајно већи укупан проценат тачних
одговора (t (135) = 2,105, p = 0,037), што указује да су виртуелне лабораторије
веома ефективне у погледу унапређивања разумевања фундаменталних хе-
мијских концепата код ученика основних школа
Identification and characterization of novel allergen candidates in blood clams (Anadara broughtonii and Tegillarca granosa) using proteomics and immunoinformatics
No full textBlood clams (Anadara broughtonii and Tegillarca granosa) are widely consumed in Southeast Asia and can trigger allergic reactions. Whereas tropomyosin and arginine kinase are established allergens, the broader allergen profile and cross-reactivity with shrimp remain poorly defined. Using gel and LC-MS-based proteomics, a novel immunoinformatic approach combining three algorithms and IgE immunoassays, we examined IgE-reactivity in shrimp-sensitized patients. Among 2580 identified proteins, 35 were from blood clams, while 9 were predicted as allergens. From IgE-reactive 2D gel spots, known allergens tropomyosin and arginine kinase were identified, and 17 novel candidate allergens were predicted, including HSP90, ferritin, and hemoglobin-Hb1. Furthermore, MHC and alpha-actinin from IgE-reactive spots were identified as abundant myofibrillar scaffold proteins lacking IUIS-registered homologues. Overall, 35% of sera reacted to blood clam proteins, with strong ELISA correlations to blue mussels. These findings expand the allergen repertoire of blood clams and highlight new candidates for food allergen risk assessment
E-Book of Abstracts: Environmental Chemistry for Sustainability, 19th International Conference on Chemistry and the Environment, Belgrade, Serbia, June 8-12, 2025
No full textICCE 2025 provides an excellent platform for networking, exchange of ideas, and collaboration. The shared mission is to deepen understanding of pollutant cycling, as well as the fate and effects of pollutants in the environment, while promoting advances in pollution prevention and waste management. The latest developments in environmental analysis, pollution monitoring, and risk assessment shape societal responses to environmental challenges, with a focus on sustainability strategies. These responses rely on robust knowledge-based tools and societal inspiration, both key offerings of ICCE 2025.Supported by Ministry of Science, Technological Development and Innovation
Research data related to blood clams and their SDS-PAGE, Immunoblot and ELISA raw images
No full textThese data set containg several unprocessed and intermediate processed scanned gels and immunoblots related to publication entitled: "Proteomic and immunoinformatic analysis reveals novel allergen candidates in blood clams" planned to be pubiished in Proteins: Structure Function and Bioinformatics. It contains 8 images of 1D, 2D electrophoretic and immunoblot profiles of Anadara borughtonii (AB) and Tegillarca granosa (TG) blood clams extracts, and each contribution is desribed in its revelant window for item description
Evaluating the Influence of Temperature on Metal Concentrations in Bottled Water Contained in PET Packaging
No full textThe safety of bottled water depends not only on the chemical composition of the content but also on the influence of packaging and storage conditions. This study aimed to investigate the effect of temperature on the concentration of metals in bottled water packaged in PET containers. Samples from six commercial brands on the domestic market were analyzed under three temperature conditions: -20 °C, 25 °C, and 40 °C. Quantitative analysis of 18 elements was performed using ICP-MS, with a particular focus on toxic metals: antimony (Sb), cadmium (Cd), and lead (Pb). The highest concentration of antimony was recorded in “Knjaz Miloš” water at 40 °C (15.59 µg/L), significantly exceeding the maximum allowed concentration for drinking water (5 µg/L, EU and EPA standards). Cadmium was detected in most samples, with the highest value observed in Voda “Voda” at -20 °C (0.50 µg/L). In most brands, a decrease in cadmium concentration was observed with increasing temperature, suggesting a possible inverse temperature trend, although inconsistent across all samples. Trace levels of lead were found in multiple samples, with a maximum of 1.76 µg/L. A weak positive correlation between temperature and the concentrations of Sb, Pb, and Cu was observed, indicating a potential temperature-induced migration of certain elements from the packaging. In addition to health-relevant elements, strontium (Sr), lithium (Li), and barium (Ba) stood out due to high variability in concentration across brands. Their stable presence and significant inter-brand differences suggest their potential application as markers of geological origin and water source type. The results emphasize the importance of monitoring the storage conditions of bottled water and the need for further investigation into the chemical stability of PET packaging under varying temperature conditions
Mesto-specifična mutageneza Ω-transaminaze ArRMut11 radi poboljšanja transaminacije dihidrotestosterona
No full textU savremenoj biohemiji i bioinženjeringu, enzimski katalizovani procesi predstavljaju ključan alat za sintezu farmaceutski relevantnih jedinjenja, nudeći ekološki prihvatljive i enantioselektivne alternative tradicionalnim hemijskim metodama. Posebno, ω-transaminaze (ω-TA) su enzimi koji omogućavaju transfer amino grupe na raznovrsne supstrate, uključujući ketone i aldehide, čime se dobijaju hiralni amini sa visokom enantiomernom čistoćom. Ovi enzimi imaju široku primenu u proizvodnji lekova, poput sitagliptina i drugih aktivnih farmaceutskih sastojaka, gde je stereoselektivnost ključna za biološku aktivnost i bezbednost.
Jedan od izazova u primeni ω-TA je njihova ograničena aktivnost prema strukturno kompleksnijim supstratima, poput steroidnih jedinjenja kao što je dihidrotestosteron (DHT). DHT je derivat testosterona sa potencijalnim farmaceutskim primenama, uključujući modifikacije za razvoj novih lekova protiv raka, hormonalnih poremećaja ili za poboljšanje anaboličkih efekata. Međutim, prirodne ω-TA često pokazuju nizak afinitet ili aktivnost prema takvim supstratima zbog sternih ograničenja u aktivnom mestu enzima. Da bi se prevazišao ovaj problem, koriste se tehnike usmerene evolucije i racionalnog dizajna, poput mesto-dirigovane mutageneze (site-directed mutagenesis), koja omogućavaju precizne izmene aminokiselinskih ostataka na tačno određenom mestu u peptidnom lancu kako bi se poboljšala katalitička efikasnost i specifičnost enzima
In vitro uvijanje rekombinantno proizvedenog proteina
No full textUvijanje proteina nije proces karakterističan samo za in vivo uslove, odnosno za ćeliju, već se može sprovesti i u laboratorijskim, in vitro uslovima. Ovu mogućnost je nagovestio i Anfinsen zaključcima svog eksperimenta.
Danas se veliki broj različitih proteina može dobiti primenom DNK rekombinantne tehnologije. Usled niske cene i brzog rasta, bakterije su često odabrani proizvodni sistem i to uglavnom Escherichia coli. Međutim, upravo se zbog brze i prekomerne ekspesije proteini pakuju u inkluziona tela tokom proizvodnje. Proteini se u inkluzionim telima nalaze u neaktivnom, neuvijenom obliku, te je neophodno izolovati inkluziona tela, a potom obezbediti uslove za ponovno uvijanje proteina u nativnu strukturu kako bi se povratila biološka aktivnost.
Kao model sistem u ovom radu je korišćena laktonaza Y2-aiiA, ekstracelularni protein koji pripada superfamiliji proteina metalo-β-laktamaza. Ova laktonaza katalizuje otvaranje laktonskog prstena u molekulu N-acil-homoserin laktona i pokazuje potencijal za utišavanje međućelijske komunikacije bakterija.
Nakon izolovanja i solubilizovanja inkluzionih tela, ispitivane su i upoređivane dve metode za in vitro uvijanje proteina: dijaliza i uvijanje na čvrstoj fazi, odnosno metal afinitetna hromatografija. Kako biološka aktivnost proteina zavisi od njegove strukture, sporvedena je strukturna analiza proteina infracrvenom spektroskopijom sa Furijerovom transformacijom (FTIR). U ovom radu je spovedena i in silico analiza strukturnih karakteristika proteina različitim bioinformatičkim alatima, u cilju utvrđivanja obrasca uvijanja
Liquid chromatography in determination of pharmacokinetic properties of compounds in drug discovery process
No full textLiquid chromatography plays a pivotal role in the determination of pharmacokinetic properties during drug discovery, particularly through the evaluation of lipophilicity. This parameter is essential in drug development, significantly influencing pharmacokinetic and pharmacodynamic behavior of potential drugs. It affects membrane permeability, solubility, distribution, and interaction with biological targets, making it a central focus in the early stages of drug design. Poor lipophilicity-related characteristics are often associated with drug failures, inefficacy, toxicity, and increased development costs. Experimental and computational methods, such as chromatographic techniques and theoretical calculations, are vital for accurately determining lipophilicity. These approaches enable the simulation of biological processes, providing insights into how lipophilicity impacts ADME (absorption, distribution, metabolism, and excretion) properties and supporting the optimization of drug candidates. In silico tools further enhance the efficiency of ADME evaluations, reducing the risk of pharmacokinetic-related failures and streamlining the drug discovery process
Novel polygalacturonase PG-BG31 prevents biofilm formation and increases antibiotic efficacy against catheter-associated Escherichia coli
No full textEscherichia coli is a leading cause of urinary tract infections, which are particularly problematic in catheterized patients due to the formation of biofilms that are resistant to standard treatments. Here we investigated a novel polygalacturonase (PG-BG31) from Pedobacter sp. BG31 and its anti-biofilm properties against E. coli isolates originating from the urine of UTI patients. The enzyme was heterologously expressed and biochemically characterized using polygalacturonic acid as substrate. The enzyme showed strong biofilm inhibition with BIC50 values between 2 and 5 µg/mL, which varied depending on the E. coli strain. It outperformed enzymes commonly used in E. coli biofilm studies, including proteinase K, DNase and cellulase. When used as a pretreatment, it significantly improved the efficacy of ciprofloxacin and trimethoprim by reducing biofilm formation by 4 log (99.99 %) at lower antibiotic concentrations. Polygalacturonase PG-BG31 works optimally at temperatures of 25 °C - 42 °C and a slightly acidic pH value (pH 5.0 – 6.0), which corresponds to the environment in urine. In addition, the enzyme showed no toxicity to cells in culture or C. elegans. These results suggest that polygalacturonase has the potential for the development of anti-biofilm strategies for catheter-related urinary tract infections