Rimantas Daugelavicius

Vytautas Magnus University · Department of Biochemistry

An increased efflux activity is one of the major reasons for bacterial antibiotic resistance. The usage of efflux pump inhibitors could be a promising approach to restoring the activity of inefficient antibiotics. The interaction of the RND family efflux pump inhibitor phenylalanyl-arginyl-β-naphthylamide (PAβN) with Salmonella enterica ser. Typhim...

The phage PRR1 belongs to the Leviviridae family, a group of ssRNA bacteriophages that infect Gram-negative bacteria. The variety of host cells is determined by the specificity of PRR1 to a pilus encoded by a broad host range of IncP-type plasmids that confer multiple types of antibiotic resistance to the host. Using P. aeruginosa strain PAO1 as a...

In the current study, a bi-layered magnetic photocatalyst powder consisting of a Ni layer on one side and carbon-doped TiO2 or ZnO photocatalyst layers on the other side was synthesized by magnetron sputtering technique. SEM, XRD, and XPS analysis of powders revealed that the photocatalytic TiO2 layer had a mixed anatase-rutile structure, was doped...

Photocatalytic treatment of contaminated aqueous solutions makes use of the specific interaction between photocatalysts and ultra-violet or visible light irradiation. This method belongs to the wider class of Advanced Oxidation Processes that generates reactive oxygen species (peroxides, superoxide, hydroxyl radical, singlet oxygen, etc.) and uses...

The beneficial photocatalytic properties of UV light activated TiO2 powder are well-known and have been demonstrated with various pollutants and pathogens. However, traditionally observed photocatalytic activity of visible light activated pristine TiO2 is insignificant but there are a few studies which have reported that under some specific conditi...

A lot of human activities have negative impact on water quality and sometimes result in the biological water contamination. Currently used chemical (chlorine, ozone, and etc.) and physical (UV) water disinfection methods have strong environmental disadvantages or suffers from limited efficiency. To overcome these problems, scientists suggest to use...

Antimicrobial resistance is a global health challenge. Few new antibiotics have been developed for use over the years, and preserving the efficacy of existing compounds is an important step to protect public health. This paper describes a study that examines the effects of exogenously induced oxidative stress on K. pneumoniae

Bacterial resistance to antibiotics due to increased efficiency of the efflux is a serious problem in clinics of infectious diseases. Knowledge of the factors affecting the activity of efflux pumps would help to find the solution. For this, fast and trustful methods for efflux analysis are needed. Here, we analyzed how the assay conditions affect t...

Mitochondria are dynamic organelles as they continuously undergo fission and fusion. These dynamic processes conduct not only mitochondrial network morphology but also activity regulation and quality control. Saccharomyces cerevisiae has a remarkable capacity to resist stress from dehydration/rehydration. Although mitochondria are noted for their r...

Bacterial resistance to antibiotics due to an increased efficiency of the efflux is a serious problem in clinics of infectious diseases. Knowledge of the factors affecting the activity of efflux pumps would help to find the solution. For this, fast and trustful methods for the efflux analysis are needed. Here we analyzed how the assay conditions af...

Hyperactivation of ABC transporter ABCB1 and induction of epithelial–mesenchymal transition (EMT) are the most common mechanism of acquired cancer chemoresistance. This study describes possible mechanisms, that might contribute to upregulation of ABCB1 and synergistically boost the acquisition of doxorubicin (DOX) resistance in breast cancer MX-1 c...

Usually, Euro banknotes are made from cotton substrates and their waste is disposed of in landfill or is incinerated. In order to valorize the end-of-life euro banknotes (ELEBs), the substrates were used in this research for cellulase production via submerged fungal fermentation (SFF), and the resultant fungal cellulase w s used in ELEBs hydrolysis...

Anhydrobiosis is the state of life when cells are exposed to waterless conditions and gradually cease their metabolism. In this study, we determined the sequence of events in Saccharomyces cerevisiae energy metabolism during processes of dehydration and rehydration. The intensities of respiration and acidification of the medium, the amounts of phen...

Anhydrobiosis is the state of life when cells get into waterless conditions and gradually cease their metabolism. In this study, we determined the sequence of events in Saccharomyces cerevisiae energy metabolism during processes of dehydration and rehydration. The intensities of respiration and acidification of the medium, the amounts of Phenyldica...

Candida albicans-caused local and systemic diseases are a serious health issue worldwide, leading to high mycosis-associated morbidity and mortality. Efficient combinations of novel compounds with commonly used antifungals could be an important tool for fighting infections. The aim of this study was to evaluate the interaction of synthesized 4-(4-c...

Water contamination by various bacteria, viruses and other pathogens is a great threat to human health. Amongst other Advanced Oxidation Processes TiO2 photocatalysis is considered as one of the most efficient treatment for the polluted wastewater disinfection. Usually, the wastewater produced by higher risk objects, such as hospitals, implicates d...

In current study UV light and visible light activated photocatalytic inactivation treatment was applied to the less commonly studied subjects, namely bacteriophages PRD1, T4 and their mixture. By using UV light irradiation and high efficiency P25 TiO2 photocatalyst powders it was demonstrated that individually and in mixture PRD1 bacteriophage is p...

In bacteria, the defense system deployd to counter oxidative stress is orchestrated by three transcriptional factors − SoxS, SoxR, and OxyR. Although the regulon that these factors control is known in many bacteria, similar data is not available for Klebsiella pneumoniae . To address this data gap, oxidative stress was artificially induced in K. pn...

We synthesized a set of 13 new and earlier described styrylpyridinium compounds (N‐alkyl styrylpyridinium salts with bromide or tosylate anions) in order to evaluate antifungal activity against C. albicans cells, to assay the possible synergism with fluconazole, and to estimate cytotoxicity to mammalian cells. All compounds were synthesized accordi...

The incidence of Candida glabrata infections increases every year due to its higher resistance to commonly used antifungal drugs. We characterized the antifungal mechanism of action of eight new styrylpyridinium derivatives, with various N-alkyl chains (-C6H13, -C8H17, -C10H21, -C12H25) and different substituents, on C. glabrata strains differing i...

10H-substituted phenothiazine and 9H-substituted carbazole derivatives are important because of a very wide range of applications and especially in medical chemistry due to their pharmacological activities. In this study, we synthesized 9H-alkylcarbazole and 10H-alkylphenothiazine derivatives with various lengths of alkyl chains and evaluated their...

Background: Xylose transport is one of the bottlenecks in the conversion of lignocellulosic biomass to ethanol. Xylose consumption by the wild-type strains of xylose-utilizing yeasts occurs once glucose is depleted resulting in a long fermentation process and overall slow and incomplete conversion of sugars liberated from lignocellulosic hydrolysa...

Background Xylose transport is one of the bottlenecks in the conversion of lignocellulosic biomass to ethanol. Xylose consumption by the wild-type strains of xylose-utilizing yeasts occurs once glucose is depleted resulting in a long fermentation process and overall slow and incomplete conversion of sugars liberated from lignocellulosic hydrolysate...

Background Xylose transport is one of the bottlenecks in the conversion of lignocellulosic biomass to ethanol. Xylose consumption by the wild-type strains of xylose-utilizing yeasts occurs once glucose is depleted resulting in a long fermentation process and overall slow and incomplete conversion of sugars liberated from lignocellulosic hydrolysate...

The anatase phase TiO2 films with nanocrystalline structure were successfully deposited on a water-floating non-expanded polystyrene (PS) beads via magnetron sputtering. The combination of UVB light and PS beads with TiO2 film was used for decomposition of methylene blue as well as inactivation tests for intact and EDTA-treated Escherichia coli bac...

The possibility of using active dry microbial preparations in biotechnological processes is essential for the development of new modern industrial technologies. In this study, we show the possibility of obtaining such preparations of the genetically engineered yeast strain Ogataea (Hansenula) polymorpha with glutathione overproduction. Special pre-...

Introduction Silver nanoparticles (AgNP) are widely used in consumer products and in medicine, mostly due to their excellent antimicrobial properties. One of the generally accepted antibacterial mechanisms of AgNP is their efficient contact with cells and dissolution in the close vicinity of bacterial cell envelope. Yet, the primary mechanism of ce...

Waste Printed Circuit Boards (WPCBs) were classified as one of the most important resources for urban mining containing high purity Copper (Cu) and other valuable materials. Recently, a dissolution recycling approach enhanced by ultrasonic treatment succeeded in the liberation of Cu foils from WPCBs as received. This research aims to synthesize Cop...

Silver nanoparticles (AgNP) are widely used in consumer products, mostly due to their excellent antimicrobial properties. One of the well-established antibacterial mechanisms of AgNP is their efficient contact with bacteria and dissolution on cell membranes. To our knowledge, the primary mechanism of cell wall damage and the event(s) initiating bac...

We show for the first time that a recombinant strain of yeast Ogataea (Hansenula) polymorpha is at least as tolerant to dehydration-rehydration treatment as the wild type strain. It is believed that this unusual characteristic of this recombinant yeast strain is linked with its ability to overproduce glutathione. Based on plasma membrane permeabili...

The aim of this study was to test and analyse the antimicrobial susceptibility of Enterococcus isolates from Lithuanian poultry farms. Investigations were carried out during the years 2008–2009. The sampling sites, located all over the country, included eight poultry farms of large capacity. All samples were collected from broilers. Enterococcus sp...

Background and objective: One of the main causes of bacterial resistance to antimicrobials is multidrug resistance induced by the increased efficiency of the efflux pumps. In this study we analyzed how the conditions of assay affect the efflux of indicator substrates ethidium (Et(+)) and tetraphenylphosphonium (TPP(+)) in Salmonella enterica ser....

Photocatalytic properties of anatase and other TiO2 polymorphs are widely researched and applied in practical application. In current study TiO2 films on the plasma pre-treated expanded polystyrene (EPS) foam were deposited using magnetron sputtering technique. Main properties of the films were characterised using combination of XRD, XPS and SEM te...

Antimicrobial textile is a very important field for new investigations. The two aspects need be taken into account at the time of such investigations into the protection of the textile itself from damage caused by microorganisms, and that of the textile user against pathogenic or odour causing microorganisms. However, it is known that some material...

Background and aim: Resistance to chemotherapy is the key obstacle to the effective treatment of various cancers. Accumulating evidence suggests significant involvement of the epithelial-to-mesenchymal transition (EMT) in the chemoresistance of most cancer types. This study aimed at analyzing the gene expression profile of doxorubicin (DOX)-resist...

The slow rate of adsorption and non-synchronous release of some archaeal viruses have hindered more thorough analyses of the mechanisms of archaeal virus release. To address this deficit, we utilized four viruses that infect Haloarcula hispanica that represent the four virion morphotypes currently known for halophilic euryarchaeal viruses: (1) icos...

Saccharomyces cerevisiae cells produce killer toxins, such as K1, K2 and K28, that can modulate the growth of other yeasts giving advantage for the killer strains. Here we focused on the physiological changes induced by K2 toxin on a non-toxin producing yeast strain as well as K1, K2 and K28 killer strains. Potentiometric measurements were adjusted...

Multidrug efflux pump inhibitors have a great potential as pharmacological agents that increase the drug susceptibility of bacterial pathogens. Our study was focused on the synthesis and evaluation of the efficiency of resistance-nodulation-division (RND) family efflux pump inhibitors. The efficiency of these inhibitors was investigated on Salmonel...

Pseudomonas aeruginosa are known to have a wide physiological potential allowing them to constantly populate diverse environments leading to severe infections of humans such as septicemia, leg ulcers and burn wounds. We set out to probe physiological characteristics of P. aeruginosa isolates from diabetic leg ulcers collected from Helsinki metropol...

In this work we present a refractive index (RI) sensor based on a sub-wavelength holographic diffraction grating. The sensor chip was fabricated by dry etching of the finely spaced (d = 428 nm) diffraction grating in SiOx doped diamond like carbon (DLC) film. It is shown that employing a fabricated sensor chip, and using the proposed method of anal...

The ζε module consists of a labile antitoxin protein, ε, which in dimer form (ε(2)) interferes with the action of the long-living monomeric ζ phosphotransferase toxin through protein complex formation. Toxin ζ, which inhibits cell wall biosynthesis and may be bactericide in nature, at or near physiological concentrations induces reversible cessatio...

Toxin expression leads to the accumulation of a novel compound. (A) xylR-PXylA, (B) lacI-Phsp (xylR-PXylAε), (C) xylR-PXylAζY83C and (D) lacI-Phspζ (xylR-PXylAε) cells were grown in MMS7 at 37°C up to ∼5×106 cells ml−1 and (32P)-KH2PO4 (50 µCi ml−1) was added and the cells were grown up to ∼5×107 cells. At time zero expression of the toxin was indu...

The accumulation of ζ-induced novel metabolite halts upon ε2 antitoxin expression. lacI-Phspζ (xylR-PXylAε) cells were grown in MMS7 at 37°C containing 0.005% Xyl (+Xyl) up to ∼5×106 cells ml−1 and (32P)-KH2PO4 (50 µCi ml−1) was added and the cells were grown up to ∼5×107 cells ml−1. At time zero the culture was divided into two aliquots and expres...

ROS accumulation is not correlated with ζ-induced membrane permeation. (DOCX)

Percentage of PI stained cells and CFUs under low ROS condition. (DOCX)

Experimental systems used. (A) Illustrations showing the structure of the empty cassette (xylR-PXylA, BG687 and its ΔrelA derivative BG1143) or the ζY83C expression cassette (xylR-PXylAζY83C, BG689 and its ΔrelA derivative BG1145) integrated as a unique copy into the B. subtilis chromosome (amy locus). (B) Illustrations showing the structure of the...

Expression of ζY83C and SHX addition increment the PI staining of siblings. xylR-PXylAζY83C cells were incubated for 120 min with Xyl 0.5% (A and B) and 1.5 mg/ml SHX (B), stained with SYTO 9 and PI and analyzed by fluorescence microscopy. White arrows show the PI staining of one sibling in the Xyl+SHX condition. (TIF)

Decreased intracellular GTP does not affect ζ-induced dormancy. (DOCX)

Bacterial strains used. (DOCX)

Gene expression response after 5 and 15 min of ζY83C toxin action. (DOCX)

The mechanism of genome transfer from the virion to the host cytoplasm is critical to understand and control the beginning of viral infection. The initial steps of bacteriophage SPP1 infection of the Gram-positive bacterium Bacillus subtilis were monitored by following changes in permeability of the cytoplasmic membrane (CM). SPP1 leads to a distin...

Entry into the host bacterial cell is one of the least understood steps in the life cycle of bacteriophages. The different envelopes of Gram-negative and Gram-positive bacteria, with a fluid outer membrane and exposing a thick peptidoglycan wall to the environment respectively, impose distinct challenges for bacteriophage binding and (re)distributi...

Marine bacteriophage PM2 infects gram-negative Pseudoalteromonas species and is currently the only assigned member of the Corticoviridae family. The icosahedral protein shell covers an internal protein-rich phage membrane that encloses the highly supercoiled dsDNA genome. In this study we investigated PM2 entry into the host. Our results indicate t...

Multidrug resistance (MDR) pumps are one of the major causes of antibiotic resistance in Pseudomonas aeruginosa. Thus, fast and reliable methods are needed to assay the efficiency of MDR pumps in these bacteria. In this study, it was demonstrated that a membrane voltage (Deltapsi) indicator tetraphenylphosphonium (TPP(+)) in combination with the ef...

The aim of this study was to test and analyse the antimicrobial susceptibility of Enterococcus isolates from Lithuanian poultry farms. Investigations were carried out during the years 2008-2009. The sampling sites, located all over the country, included eight poultry farms of large capacity. All samples were collected from broilers. Enterococcus sp...

K. Čiurlionio g. 21, LT-03101 Vilnius, Lithuania 3 Jakovo veterinarijos centras, Gerosios vilties g. Summary. The aim of this study was to determine minimal inhibitory concentration (MIC) values of Escherichia coli and Salmonella enterica as the most important bacteria family Enterobacteriaceae and to evaluate their clinical and epidemiological res...

105 isolates of Enterococcus spp. were selected as representative samples from different herds of pigs (n=25), cattle (n=46) and poultry (n=34). Antimicrobial susceptibility was determined according to epidemiological cut-off values. The highest number of strains demonstrated epidemiological resistance to lincomycin (78%), tetracycline, (65%), flav...

Antimicrobial susceptibility of Escherichia coli isolated from humans, cattle, pigs and poultry was investigated by a micro-dilution test. Epidemiological cut-off values and clinical breakpoints were determined in the course of investigations. One hundred and thirty seven isolates from cattle, pigs and poultry and 38 isolates from humans were obtai...

105 isolates of Enterococcus spp. were selected as representative samples from different herds of pigs (n=25), cattle (n=46) and poultry (n=34). Antimicrobial susceptibility was determined according to epidemiological cut-off values. The highest number of strains demonstrated epidemiological resistance to lincomycin (78%), tetracycline, (65%), flav...

We have analysed the photodynamic action of the cationic photosensitiser tetrakis(N-ethyl-pyridinium-4-yl)porphyrin tetratosylate (TN-Et-PyP) on the integrity and functions of E. coli AN 180 cell membranes. Photosensitisation of bacterial cells with photobactericidal concentrations of TN-Et-PyP resulted in abolition of plasma membrane (PM) voltage...

The aim of this study was to investigate situation of antimicrobial resistance of enterococci isolated from animal origin and to identify possible differences between enterococci isolated from healthy and sick animals in the context of resistance. During this study 83 representative strains of Enterococcus spp. isolated from cattle, pigs and poultr...

In this study we investigated the lysis system of the lipid-containing double-stranded DNA bacteriophage PM2 infecting Gram-negative marine Pseudoalteromonas species. We analysed wt and lysis-deficient phage-induced changes in the host physiology and ascribed functions to two PM2 gene products (gp) involved in lysis. We show that bacteriophage PM2...

In this study an on-line electrochemical method was developed to examine the one-step growth cycle (OSGC) of the bacteriophage Bam35. The on-line conditions for monitoring the OSGC and the effect of aeration on the duration of the OSGC were defined. The data indicate that binding of phenyldicarbaundecaborane anions to Bacillus thuringiensis cells i...

The aim of this study to isolate E. coli from animal origin and to determine resistance to antimicrobials. Clinical and pathological material from sick and dead animals was collected from different regions of Lithuania. Cattle, pigs and poultry were included in this study. As control E coli isolated from healthy animals was also tested. Disc diffus...

Polymyxin B (PMB) is a cationic antibiotic that interacts with the envelopes of gram-negative bacterial cells. The therapeutic use of PMB was abandoned for a long time due to its undesirable side effects; however, the spread of resistance to currently used antibiotics has forced the reevaluation of PMB for clinical use. Previous studies have used e...

Gp7 is a minor capsid protein of the Bacillus subtilis bacteriophage SPP1. Homologous proteins are found in numerous phages but their function remained unknown. Deletion of gene 7 from the SPP1 genome yielded a mutant phage (SPP1del7) with reduced burst-size. SPP1del7 infections led to normal assembly of virus particles whose morphology, DNA and pr...

The temperate double-stranded DNA bacteriophage Bam35 infects gram-positive Bacillus thuringiensis cells. Bam35 has an icosahedral protein coat surrounding the viral membrane that encloses the linear 15-kbp DNA genome. The protein coat of Bam35 uses the same assembly principle as that of PRD1, a lytic bacteriophage infecting gram-negative hosts. In...

Bam35, a temperate double-stranded DNA bacteriophage with a 15-kb linear genome, infects gram-positive Bacillus thuringiensis cells. Bam35 morphology and genome organization resemble those of PRD1, a lytic phage infecting gram-negative bacteria. Bam35 and PRD1 have an outer protein coat surrounding a membrane that encloses the viral DNA. We used el...