Publications by authors named "Petra Olejnikova"

Article Synopsis
  • Multidrug-resistant bacterial infections are a growing global health issue, prompting research into new antibacterial compounds.
  • A new class of compounds called 3-substituted benzoazepinedione derivatives shows strong antibacterial activity against both drug-susceptible and drug-resistant bacteria, with the key compound exhibiting a minimum inhibitory concentration (MIC) as low as 2 μg/mL.
  • The thia-Michael adduct 10d has a lower toxicity profile in cell tests compared to its parent compound, suggesting potential for safer drug development, and stability studies indicate these compounds maintain stability under neutral conditions while reacting under mildly basic environments.
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Two In(III) - pyridinecarboxylates ([In(Pic)(NO)(HO)] (InPic; HPic = picolinic acid), [In(HDpic)(Dpic)(HO)]·5HO (InDpic; HDpic = dipicolinic acid), have been synthesized by one-step procedure. The complexes composition was confirmed by physicochemical analyses and X-ray diffraction confirmed molecular structure of both complexes. Moreover, complex species speciation was described in both systems by potentiometry and H NMR spectroscopy and mononuclear complex species were determined; [In(Pic)] (logβ = 6.

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Diseases caused by various microorganisms accompany humans (as well as animals) throughout their whole lives. After germs penetration to the body, the incubation period and infection developing, an infection can cause mild or severe symptoms, not infrequently even death. The immune system naturally defends itself against pathogens with various mechanisms.

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A series of novel Ga(III)-pyridine carboxylates ([Ga(Pic)]·HO (GaPic; HPic = picolinic acid), HO[Ga(Dpic)]·HO (GaDpic; HDpic = dipicolinic acid), [Ga(Chel)(HO)(OH)]·4HO (GaChel; HChel = chelidamic acid) and [Ga(Cldpic)(HO)(OH)] (GaCldpic; HCldpic = 4-chlorodipicolinic acid)) have been synthesized by simple one-step procedure. Vibrational spectroscopy (mid-IR), elemental analysis, thermogravimetric analysis and X-ray diffraction confirmed complexes molecular structure, inter and intramolecular interactions and their influence to spectral and thermal properties. Moreover, complex species speciation was described in Ga(III)-HPic and Ga(III)-HDpic systems by potentiometry and H NMR spectroscopy and mononuclear complex species were determined; [Ga(Pic)] (logβ = 16.

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Two silver(I) complexes with biologically relevant heterocyclic ligands, pyrrole and furan-2- carboxylic acid, were synthesized and their composition was confirmed using elemental, spectral, thermal and structural analyses. The {[Ag(Py2c)]} (AgPy2c, Py2c = pyrrole-2-carboxylate) and {[Ag(Fu2c)]} (AgFu2c, Fu2c = furan-2-carboxylate) solubility and stability in biological test stock solution were confirmed by H NMR spectroscopy. The X-ray analysis has enabled us to determine typical argentophilic interactions and bridging carboxylate coordination mode of both ligands.

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Murine herpesvirus 68 (MHV-68) belongs to the subfamily Gammaherpesvirinae of the family Herpesviridae. This exceptional murine herpesvirus is an excellent model for the study of human gammaherpesvirus infections. Cells infected with MHV-68 under nonpermissive conditions for viral replication produce substances designated as MHV-68 growth factors (MHGF-68), that can cause transformation of the cells, or on the other side, turn transformed cells into normal.

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The presence of antifungal drugs is prompting the fungal microorganisms to react by mechanisms broader than the resistance. The fungi evolved mechanisms, by which they respond to various stress conditions, including the presence of antifungal compounds. In this work, we studied the response of model filamentous fungus Neurospora crassa to azole antifungals in the broader context of the adaptation mechanisms.

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Berkeleylactone A is a potent 16-membered macrolactone antibiotic, recently isolated from a coculture of Berkeley Pit Lake fungi. Although its antimicrobial activity has already been investigated, little is known about the structure-activity relationship. Based on our previous synthetic studies, a series of berkeleylactone A derivatives were synthesized and evaluated for their antimicrobial activities against methicillin-sensitive and methicillin-resistant (MRSA) strains.

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Raw foodstuffs have been marked as a healthier alternative in the context of nutrient content and are becoming more popular with consumers. Thermally untreated foods may represent a microbiological risk connected with the possible presence of antimicrobial resistance. The aim of this study was to prove that popular raw food beverages such as smoothies and raw milk may be a source of antibiotic-resistant coliform bacteria and resistant genes.

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Due to its slow degradation rate, polycaprolactone (PCL) is frequently used in biomedical applications. This study deals with the development of antibacterial nanofibers based on PCL and halloysite nanotubes (HNTs). Thanks to a combination with HNTs, the prepared nanofibers can be used as low-cost nanocontainers for the encapsulation of a wide variety of substances, including drugs, enzymes, and DNA.

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Three silver(I) dipeptide complexes [Ag(GlyGly)](NO) (AgGlyGly), [Ag(GlyAla)(NO)] (AgGlyAla) and [Ag(HGlyAsp)(NO)] (AgGlyAsp) were prepared, investigated and characterized by vibrational spectroscopy (mid-IR), elemental and thermogravimetric analysis and mass spectrometry. For AgGlyGly, X-ray crystallography was also performed. Their stability in biological testing media was verified by time-dependent NMR measurements.

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Fighting resistance to antibiotics and chemotherapeutics has brought bioactive peptides to the fore. Peptaibols are short α-aminoisobutyric acid-containing peptides produced by species. Here, we studied the production of peptaibols by O1 and evaluated their antibacterial and anticancer activity against drug-sensitive and multidrug-resistant bacterium and cancer cell lines.

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Among the many consumers in Slovakia, smoothies are nowadays gaining popularity. Smoothie drinks are prepared from raw fruits and vegetables. Therefore, their microbiological safety depends on hygiene standards.

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The superfamily of ATP-binding cassette (ABC) transporters is a large family of proteins with a wide substrate repertoire and range of functions. The main role of these proteins is in the transportation of different molecules across biological membranes. Due to the broad range of substrates, ABC transporters can transport not only natural metabolites but also various xenobiotics, including antifungal compounds, which makes some ABC transporters key players in antifungal resistance.

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This work compares the prevalence of antibiotic resistant coliform bacteria in hospital wastewater effluents in Slovak (SR) and Czech Republic (ČR). It also describes selected antibiotic resistant isolates in view of resistance mechanism and virulence factor. The highest number of multidrug resistant bacteria was detected in samples from the hospital in Valašské Meziříčí (ČR).

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The emergence of antifungal resistance is a serious threat in the treatment of mycoses. The primary susceptible fungal cells may evolve a resistance after longer exposure to antifungal agents. The exposure itself causes stress condition, to which the fungus needs to adapt.

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Two silver(I) aminoacidate complexes {[Ag(L-HAla)(NO)]NO} (AgAla, complex 1, Ala = alanine) and {[Ag(L-Phe)]} (AgPhe, complex 2, Phe = phenylalanine) were prepared and characterized by elemental, spectral analysis (FT-IR, NMR techniques) and single crystal X-ray analysis in solid state and their solution stability was measured in biological testing time-scale by H NMR. The bridging coordination modes of the zwitterionic Ala and deprotonated Phe ligands led to the formation of 1D polymeric chains of the complexes. The significant argentophilic interactions are presented in the structure of AgAla.

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We describe the screening of a set of cryptopleurine derivatives, namely thienoquinolizidine derivatives and (epi-)benzo analogs with bioactive phenanthroquinolizidine alkaloids that induce cytotoxic effects in the mouse lymphocytic leukemia cell line L1210. We used three variants of L1210 cells: i) parental cells (S) negative for P-glycoprotein (P-gp) expression; ii) P-glycoprotein positive cells (R), obtained by selection with vincristine; iii) P-glycoprotein positive cells (T), obtained by stable transfection with a human gene encoding P-glycoprotein. We identified the most effective derivative with a median lethal concentration of ≈13 μM in all three L1210 cell variants.

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The first total synthesis of the potent antibiotic berkeleylactone A is described in 10 steps with an overall yield of 9.5%. A key step of our concise route is a late-stage, highly diastereoselective, sulfa-Michael addition.

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Wastewater contains subinhibitory concentrations of different micropollutants such as antibiotics that create selective pressure on bacteria. This phenomenon is also caused by insufficient wastewater treatment technology leading to the development and spread of antibiotic-resistant bacteria and resistance genes into the environment. Therefore, this work focused on monitoring of antibiotic-resistant coliform bacteria and enterococci in influent and effluent wastewaters taken from the second biggest wastewater treatment plant (Petržalka) in the capital of Slovakia during 1 year.

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Pathogenic fungi, as an increasing global threat to human health, represent a sizable risk. However, significant attention should also be paid to the yeast biofilms. One promising strategy for combating resistant microbes, as well as fungal biofilms, is to extend the lifespan and efficacy of our currently employed drugs by using combination therapy.

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Objectives: Urban wastewater contains various micropollutants and a high number of different micro-organisms. Some bacteria in wastewater can attach to surfaces and form biofilm, which gives bacteria an advantage in the fight against environmental stresses. This work focused on analysis of bacterial communities in biofilms isolated from influent and effluent sewerage of a wastewater treatment plant (WWTP) in Bratislava, Slovakia.

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A series of polynitroxide amides possessing 2,2,5,5-tetramethyl-1-pyrrolidinyloxy (PROXYL) and/or 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) units connected through various bridges were synthesized and their properties were analyzed. EPR spectroscopy provided detailed insight into their paramagnetic character and related properties. A thorough examination of the EPR spectra of dinitroxides in organic solvents provided valuable information on the intramolecular motions, thermodynamics, and spin-exchange mechanisms.

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With emerging fungal infections and developing resistance, there is a need for understanding the mechanisms of resistance as well as its clinical impact while planning the treatment strategies. Several approaches could be taken to overcome the problems arising from the management of fungal diseases. Besides the discovery of novel effective agents, one realistic alternative is to enhance the activity of existing agents.

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Isolates of anaerobic fungi from rumen, animal faeces and compost displayed morphological similarity with known anaerobic fungi. According to their ITS sequences, species were related to Neocallimastix and Piromyces. Rumen fungi tolerated exposure to an aerobic atmosphere for at least four days.

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