Antibakterijsko i antifungalno djelovanje klorheksidin-diacetata ugrađenog u akrilatne smole koje se upotrebljavaju za privremene nadomjestke

Objective: The surface of provisional restorations applied before conventional or implant- supported fixed restorations may cause bacterial or fungal biofilm formation. The aim of this study was to evaluate the antimicrobial activity of acrylic resins used in provisional restorations modified with chlorhexidine diacetate. Methods: 120 cylindrical, auto-polymerized resin samples modified with chlorhexidine diacetate were prepared at concentrations of 0 (control), 1, 3, 5 wt %. The antimicrobial activity was examined against Streptococcus mutans, Enterococcus faecalis, and Candida albicans using Crystal Violet quantification, MTT assay, and Scanning Electron Microscopy. Data were analyzed by ANOVA and paired sample t-tests (α=0.05). Results: The addition of chlorhexidine diacetate influenced the growth rate and metabolic activity of microorganisms. The antimicrobial effect against C. albicans and S. mutans statistically increased with the percentage of chlorhexidine diacetate. E. faecalis bacteria were less affected by chlorhexidine diacetate compared to other pathogens. Conclusion: It has been shown that the effectiveness of CHDA in inhibiting the proliferation of microorganisms correlated positively with increasing concentration levels. More research is needed to confirm the impact of different chlorhexidine concentrations on the mechanical properties, clinical efficacy, and antimicrobial properties of CDHA.Svrha istraživanja: Površina privremenih nadomjestaka koji se koriste prije trajnih fiksnih nadomjestaka ili nadomjestaka postavljenih na implantate može prouzročiti stvaranje bakterijskoga ili gljivičnoga biofilma. Cilj ovog istraživanja bio je procijeniti antimikrobno djelovanje akrilatnih smola koje se upotrebljavaju u privremenim restauracijama modificiranima klorheksidin-diacetatom. Materijal i metode: Pripremljeno je 120 cilindričnih, autopolimeriziranih uzoraka smole modificirane klorheksidin-diacetatom u koncentracijama od 0 (kontrola), 1, 3, 5 težinskih postotaka. Antimikrobna aktinost ispitivana je za mikroorganizme Streptococcus mutans, Enterococcus faecalis i Candida albicans kvantifikacijom Crystal Violeta, MTT testom i skenirajućom elektronskom mikroskopijom. Podatci su analizirani ANOVA-om i t-testom uparenih uzoraka (α = 0,05). Rezultati: Dodatak klorheksidin-dia-cetata utjecao je na brzinu rasta i metaboličku aktivnost mikroorganizama. Antimikrobni učinak kad je riječ o C. albicans i S. mutans statistički se povećavao s postotkom klorheksidin-diacetata. Bakterija E. faecalis bila je manje pogođena klorheksidin-diacetatom u usporedbi s drugim patogenima. Zaključak: Pokazalo se da učinkovitost CHDA-e u inhibiciji proliferacije mikroorganizama pozitivno korelira s povećanjem razine koncentracije. Potrebna su dodatna istraživanja kako bi se utvrdio utjecaj različitih koncentracija klorheksidina na mehanička svojstva, kliničku učinkovitost i antimikrobna svojstva CDHA-e

Anti-Quorum Sensing Potential of Antioxidant Quercetin and Resveratrol

Quorum sensing system plays an active role in the regulation of pathogenicity of many microorganisms. Inhibition of pathogenicity or virulence factors will increase the success of treatment by preventing the development of antibiotic resistance. In this study, anti-quorum sensing activities of quercetin and resveratrol compounds, which have antioxidant property without damaging to host, have been determined via using biosensor bacteria: Chromobacterium violaceum ATCC 12472 and Chromobacterium violaceum CV026. As quorum sensing inhibitors, quercetin and resveratrol's cutting off the bacterial communication will prevent the treatment failures caused by the development of bacterial resistance. The development of layered drugs with antioxidant compounds such as quercetin and resveratrol will pave the way for new horizons for new therapeutic strategies.Wo

The Antibacterial and Antifungal Activity of Chlorhexidine Diacetate Incorporated into Acrylic Resins Used in Provisional Restorations

Objective: The surface of provisional restorations applied before conventional or implant- supported fixed restorations may cause bacterial or fungal biofilm formation. The aim of this study was to evaluate the antimicrobial activity of acrylic resins used in provisional restorations modified with chlorhexidine diacetate. Methods: 120 cylindrical, auto-polymerized resin samples modified with chlorhexidine diacetate were prepared at concentrations of 0 (control), 1, 3, 5 wt %. The antimicrobial activity was examined against Streptococcus mutans, Enterococcus faecalis, and Candida albicans using Crystal Violet quantification, MTT assay, and Scanning Electron Microscopy. Data were analyzed by ANOVA and paired sample t-tests (α=0.05). Results: The addition of chlorhexidine diacetate influenced the growth rate and metabolic activity of microorganisms. The antimicrobial effect against C. albicans and S. mutans statistically increased with the percentage of chlorhexidine diacetate. E. faecalis bacteria were less affected by chlorhexidine diacetate compared to other pathogens. Conclusion: It has been shown that the effectiveness of CHDA in inhibiting the proliferation of microorganisms correlated positively with increasing concentration levels. More research is needed to confirm the impact of different chlorhexidine concentrations on the mechanical properties, clinical efficacy, and antimicrobial properties of CDHA

Comparative Study of Inhibitory Potential of Dietary Phytochemicals Against Quorum Sensing Activity of and Biofilm Formation by Chromobacterium violaceum 12472, and Swimming and Swarming Behaviour of Pseudomonas aeruginosa PAO1

Quorum sensing (QS) and biofilm formation are important mechanisms related to antibiotic resistance of many pathogens. Alternative treatments are needed to prevent recurrent or chronic infections caused by multi-resistant pathogens. Therefore, the aim of this study is to investigate and compare the inhibitory potential of the dietary phytochemicals: curcumin, quercetin, apigenin, pyrogallol, gallic acid and luteolin against QS of and biofilm formation by Chromobacterium violaceum ATCC 12472 and the swimming and swarming abilities of Pseudomonas aeruginosa PAO1. Anti-QS potential of the phytochemicals was evaluated qualitatively and quantitatively using C. violaceum via the disk diffusion assay based on violacein pigment inhibition at the subminimal inhibitory concentrations ranging from 46.87 to 750 mu g/mL. The results of anti-QS and antibiofilm activities on C. violaceum demonstrated that all the phytochemicals except pyrogallol and gallic acid inhibited violacein production (from (11.0 +/- 0.1) to (88.2 +/- 0.1) \%) in a concentration-dependent manner. In addition, the biofilm formation was also significantly inhibited (p<0.05) in the presence of all the phytochemicals ((1.38 +/- 0.08)-(84.2 +/- 0.2) \%). In the present study, the results revealed that quercetin, curcumin, apigenin and luteolin could be promising QS and biofilm inhibitory agents against the C. violaceum 12472 biosensor system. Our findings also suggest that all the phytochemicals, especially curcumin, quercetin and pyrogallol, might be anti-pathogenic agents against P. aeruginosa PAO1 infections due to the ability to control QS. However, more comprehensive studies at the molecular level, explaining their anti-QS mechanisms, need to be conducted to confirm these results and identify the genes involved

Synthesis and characterization of silver nanoparticles integrated in polyvinyl alcohol nanofibers for bionanotechnological applications

Characterization and microbial growth activity of polyvinyl alcohol (PVA) nanofibers (NFs) produced by an electrospinning technique containing different amounts of silver nanoparticles (AgNPs) was investigated. AgNPs were synthesized by chemical reduction of silver nitrate (AgNO3) (in different weight ratios) in PVA solution followed by electrospinning to produce PVA/AgNPs NFs. The properties of PVA/AgNPs NFs were studied as a function of the silver content. The morphology and distribution of NFs and AgNPs were characterized by transmission and scanning electron microscopy. The size of NFs was 135-160 nm, and the size of AgNPs was 15-27 nm. TEM images clearly showed that spherical AgNPs were homogeneously integrated in PVA NFs. The microbial activity of NFs containing different amounts of AgNPs was examined against both Gram-negative (Pseudomonas aeruginosa and Escherichia coli) and Gram-positive (Bacillus megaterium and Staphylococcus aureus) bacteria and against Candida albicans. PVA NFs containing AgNPs exhibited increasing inhibitory effects against microbial pathogenic strains with increasing AgNPs amounts. The results suggest that PVA/AgNPs NFs could be used for wound dressing components, protective coatings, biomedical devices, and water purification

DNA interaction, antitumor and antimicrobial activities of three-dimensional chitosan ring produced from the body segments of a diplopod

Commercially available chitins and the chitin isolated from mushrooms, insect cuticles, shells of shrimp, crab and crayfish reported in the literature are in forms of powder, flake or granule. Threedimensional chitins have been only known from the sponges but still threedimensional chitosan has not been reported yet. In this study, we produced threedimensional chitin and chitosan rings from the body segments of a diplopod species (Julus terrestris). Obtained chitin and chitosan rings were characterized (by FTIR, SEM, TGA, XRD, dilute solution viscometry and EA) and compared with commercial chitin and chitosan. The interactions with plasmid DNA was studied at varying concentrations of chitosan (0.04, 0.4 and 4 mg/mL). Antitumor activity tests were conducted (L929 and HeLa), low cytotoxicity and high antiproliferative activity was observed. Antimicrobial activities of J. terrestris chitosan were investigated on twelve microorganisms and maximum inhibition (15.6 ± 1.154 mm) was recorded for common human pathogen Staphylococcus aureusBiologijos katedraFizikos katedraGamtos mokslų fakultetasVytauto Didžiojo universiteta

Biological, mechanical, optical and physicochemical properties of natural chitin films obtained from the dorsal pronotum and the wing of cockroach

In previous studies, chitin-based films were produced from chitin nanofibers in dust form and fully characterized. However, chitin films naturally present in many organisms have not been isolated and characterized. Herein, structurally intact chitin films were successfully extracted from the dorsal pronotum and the wing of cockroach. Despite using the same extraction procedure, important differences were observed. Especially, hydrophobicity, transparency, antifungal and antibacterial biofilm activities of wing chitin film were recorded notably higher than those of chitin film from the dorsal pronotum. However, better mechanical properties were observed for chitin film from the dorsal pronotum. Notably, among the tested bacteria, two common pathogens could not form biofilms on the surface of the films. This study clearly demonstrated natural chitin films obtained from an insect can provide a new perspective to chitin-based applications where chitin films with high thermal stability, transparency, resistance to bacterial biofilm formation and antifungal activity are neededBiologijos katedraGamtos mokslų fakultetasVytauto Didžiojo universiteta

Conversion of waste parasite insect (Hylobius Abietis L.) into antioxidative, antimicrobial, biodegradable and edible films

Hylobius abietis is a plant parasitic insect belonging to the order Coleoptera and causes severe damages to coniferous forests in Northern and Eastern Europe. This current study aimed to provide a new viewpoint to waste of this insect by producing chitosan. Dry insect corpses consisted of 27.9% chitin, and 86.2% of chitin was converted into chitosan. FT-IR spectra analyses confirmed the purity and deacetylation degree of the produced chitosan (molecular weight of chitosan; 7.3 kDa). This chitosan exhibited antimicrobial activity against 18 bacterial strains. Further, biodegradable chitosan composite films with β-carotene were produced. Antioxidant activity of chitosan films were found to be higher than chitosan gels; and β-carotene incorporation further increased the antioxidative properties of the chitosan films. This study demonstrated that the waste of parasitic insect like H. abietis can be evaluated as a source for production of biodegradable and edible chitosan-based films for applications in food coatingBiologijos katedraVytauto Didžiojo universitetasŽemės ūkio akademij