Antifungal Activity of Newly Formed Polymethylmethacrylate (PMMA) Modification by Zinc Oxide and Zinc Oxide-Silver Hybrid Nanoparticles.

Incorporating nanoparticles into denture materials shows promise for the prevention of denture-associated fungal infections. This study investigates the antifungal properties of acrylic modified with microwave-sintered ZnO-Ag nanoparticles. ZnO-Ag nanoparticles (1% and 2.

Herbal Polyphenols as Selenium Reducers in the Green Synthesis of Selenium Nanoparticles: Antibacterial and Antioxidant Capabilities of the Obtained SeNPs.

Selenium is an essential trace element for the proper functioning of the human body. In recent years, great attention has been paid to selenium nanoparticles (SeNPs) due to their potential for medicinal applications. In this study, herbal extracts were used in the green synthesis of SeNPs.

A Comprehensive Study of the Microbiome, Resistome, and Physical and Chemical Characteristics of Chicken Waste from Intensive Farms.

The application of chicken waste to farmland could be detrimental to public health. It may contribute to the dissemination of antibiotic-resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) from feces and their subsequent entry into the food chain. The present study analyzes the metagenome and resistome of chicken manure and litter obtained from a commercial chicken farm in Poland.

The Effect of Silver Nanoparticles on PCM2191 Peptidoglycan Metabolism and Cell Permeability.

Listeria monocytogenes is Gram-positive bacterial pathogen, a causative agent of food poisoning and systemic disease - listeriosis. This species is still susceptible to several conventionally used antibiotics but an increase in its resistance has been reported. For this reason the search for new, alternative therapies is an urgent task.

The activity of silver nanoparticles against microalgae of the Prototheca genus.

Aim: To investigate the in vitro activity of silver NPs (AgNPs) against pathogenic microalgae of the Prototheca genus.

Materials & Methods: The antialgal potential of AgNPs against Prototheca species of both clinical and environmental origin was assessed from minimum inhibitory (algistatic) and algicidal concentrations. The in vitro cytotoxicity of AgNPs against bovine mammary epithelial cell line was evaluated by means of the standard MTT assay.

Effects of null mutation of the heat-shock gene htpG on the production of virulence factors by Pseudomonas aeruginosa.

Aim: Pseudomonas aeruginosa is one of the most clinically important opportunistic pathogen in humans. The aim of the project was to study effects of HtpG on the selected virulence factors responsible for pathogenesis and biofilm formation of P. aeruginosa.

Preparation and characterization of ZnO-PMMA resin nanocomposites for denture bases.

Purpose: The aim of the paper was to investigate the antifungal activity of zinc oxide nanoparticles (ZnONPs) against Candida albicans. Some attempts have been made to find out the best way to introduce ZnONPs into polymethyl methacrylate (PMMA) resin material and to determine some parameters of a newly formed composite.

Material And Methods: Zinc oxide nanoparticles were manufactured and their basic physical parameters were determined (average particle size, density, specific surface area).

Significance of polymethylmethacrylate (PMMA) modification by zinc oxide nanoparticles for fungal biofilm formation.

The objective of this study was to obtain a material composite with antifungal properties for dentures to be used as an alternative protocol in denture stomatitis treatment and prevention. Denture stomatitis is still a clinical problem in patients particularly vulnerable to this disease. Composites of PMMA and doped ZnO-NPs (weight concentrations, 2.

Chaperone DnaJ Influences the Formation of Biofilm by Escherichia coli.

DnaJ chaperone, a member of the so called DnaK-DnaJ-GrpE chaperone machine plays an important role in cell physiology. The ability of Escherichia coli ΔdnaJ mutant to form biofilm was studied. It was shown that this mutant is impaired in biofilm development when exposed to 42 degrees C for 2 h.

Genetic control of bacterial biofilms.

Nearly all bacterial species, including pathogens, have the ability to form biofilms. Biofilms are defined as structured ecosystems in which microbes are attached to surfaces and embedded in a matrix composed of polysaccharides, eDNA, and proteins, and their development is a multistep process. Bacterial biofilms constitute a large medical problem due to their extremely high resistance to various types of therapeutics, including conventional antibiotics.

Interactions of Escherichia coli molecular chaperone HtpG with DnaA replication initiator DNA.

The bacterial chaperone high-temperature protein G (HtpG), a member of the Hsp90 protein family, is involved in the protection of cells against a variety of environmental stresses. The ability of HtpG to form complexes with other bacterial proteins, especially those involved in fundamental functions, is indicative of its cellular role. An interaction between HtpG and DnaA, the main initiator of DNA replication, was studied both in vivo, using a bacterial two-hybrid system, and in vitro with a modified pull-down assay and by chemical cross-linking.

The effect of oleanolic and ursolic acids on the hemolytic properties and biofilm formation of Listeria monocytogenes.

Oleanolic acid and ursolic acid are pentacyclic triterpenoids isolated from a variety of medicinal plants, which have antibacterial activity. Listeria monocytogenes is a Gram-positive facultative pathogen, being the causative agent of listeriosis. The present study was carried out to evaluate the in vitro effect of sub-inhibitory concentrations of both triterpene acids on the pathogenicity determinants of L.

Modulation of antibiotic resistance and induction of a stress response in Pseudomonas aeruginosa by silver nanoparticles.

The objective of this study was to characterize the effects of silver nanoparticles on Pseudomonas aeruginosa. Their interactions with several conventional antibiotics and ability to induce a stress response were examined. Interactions between silver nanoparticles (AgNPs) and antibiotics against free-living cells and biofilm of P.

Silver nanoparticles as an alternative strategy against bacterial biofilms.

Biofilms are complex bacterial communities that resist the action of antibiotics and the human immune system. Bacteria within biofilms are the cause of numerous, almost impossible to eradicate, persistent infections. Biofilms can form on many medical devices and implants, and so have an enormous impact on medicine.

Physiological consequences of mutations in the htpG heat shock gene of Escherichia coli.

Mutation of the heat shock gene, htpG, causes severe defects of several cellular functions in Escherichia coli. A null htpG mutant constructed by gene replacement was impaired in the biosynthesis and secretion of several enzymes, and in biofilm formation and proteolysis. A significant decrease in the activity of β-lactamase in the ΔhtpG mutant was observed at 42°C.

New antibacterial therapeutics and strategies.

Studies on new antibacterial therapeutics and strategies are currently being conducted in many microbiological, pharmaceutical and biochemical laboratories. The antibacterial activity of plant-derived compounds as well as silver and gold nanoparticles is the subject of this minireview. The application of photodynamic therapy is also discussed.

Oleanolic and ursolic acids influence affect the expression of the cysteine regulon and the stress response in Escherichia coli.

The pentacyclic triterpenoids, oleanolic, and ursolic acids, affect peptidoglycan metabolism, altering bacterial morphology, and inhibit the growth and survival of several bacterial species, including pathogenic ones. We investigated the effect of subinhibitory concentrations of these compounds on the expression of three operons from the E. coli cysteine regulon, cysPTWA, cysJIH, and cysB, by using transcriptional fusions with the lacZ reporter gene.

Oleanolic acid and ursolic acid affect peptidoglycan metabolism in Listeria monocytogenes.

The plant pentacyclic triterpenoids, oleanolic and ursolic acids, inhibit the growth and survival of many bacteria, particularly Gram-positive species, including pathogenic ones. The effect of these compounds on the facultative human pathogen Listeria monocytogenes was examined. Both acids affected cell morphology and enhanced autolysis of the bacterial cells.

Antibacterial and antiparasitic activity of oleanolic acid and its glycosides isolated from marigold (Calendula officinalis).

The antibacterial and antiparasitic activities of free oleanolic acid and its glucosides and glucuronides isolated from marigold (Calendula officinalis) were investigated. The MIC of oleanolic acid and the effect on bacterial growth were estimated by A600 measurements. Oleanolic acid's influence on bacterial survival and the ability to induce autolysis were measured by counting the number of cfu.

Conjugal transfer of plasmid R6K gamma ori minireplicon derivatives from Escherichia coli to various genera of pathogenic bacteria.

Three R6K-derived gamma ori minireplicons were successfully transferred by conjugation from Escherichia coli to several species of pathogenic bacteria. The pFL129 replicon encodes the wild-type initiation replication protein pi, while plasmids pFL130 and pAG101 encode mutant forms of the pi protein conferring the plasmid copy-up phenotype. Plasmids could be transferred to all recipient species tested, although high efficiency conjugal transfer was only obtained with genera of the Enterobacteriaceae.

Genetic and physiological regulation of bacterial endospore development.

Bacterial endospores are complex structures residing inside endospore-forming, mainly gram-positive bacteria. The process of sporulation is considered a simple example of cell differentiation. Endospores enable the organism to resist environmental stresses.

New methods of pathogenic bacteria elimination.

The growing bacterial resistance to antibiotics calls for the elaboration of new pathogens elimination strategies. Some of these methods are based on the conjugative transfer of recombinant plasmids able to eliminate pathogenic recipients by plasmid run-away replication or by killing activity of plasmid-encoded bacteriocins. Using live bacteria as donors of plasmid vectors carrying killing determinants requires meeting many safety restrictions in order to eliminate potential biohazard.

Role of Escherichia coli DnaK and DnaJ chaperones in spontaneous and induced mutagenesis and their effect on UmuC stability.

The frequency of spontaneous as well as induced reversions of auxotrophic mutations in Escherichia coli AB1157 and its DeltadnaK and DeltadnaKdnaJ derivatives was estimated. The obtained results demonstrate that both mutants tested are characterized by elevated frequency of spontaneous reversions compared to their AB1157 parent. In contrast, the frequency of reversions induced by UV and MMS, i.

Influence of DnaK and DnaJ chaperones on Escherichia coli membrane lipid composition.

The content of fatty acids extracted from the membranes of E. coli MC 1061 harboring the wild-type dnaKdnaJ alleles and its delta dnaJ and delta dnaKdnaJ derivatives was compared. It was demonstrated that dodecanoic acid was missing in NPLs fraction extracted from both mutants grown at 42 degrees C.

Effect of null mutations in dnaK and dnaJ genes on conjugational DNA transfer, proteolysis and novobiocin susceptibility of Escherichia coli.

Escherichia coli null dnaJ and dnaKdnaJ mutants, when introduced to Hfr donor, impair its ability to DNA transfer during conjugation. The additive effect of both mutations was shown. Lack of DnaK and DnaJ chaperones also decrease the extent of proteolysis in mutant strains.