Rimantas Daugelavicius - Academia.edu (original) (raw)

Papers by Rimantas Daugelavicius

Background. Multidrug resistance (MDR) is a significant problem that determine failures of chemot... more Background. Multidrug resistance (MDR) is a significant problem that determine failures of chemotherapy of human malignancies. The main mechanism of MDR is ATP-binding cassette (ABC) efflux transporters that exist in all living cells (1). The biggest problem is that ABC efflux pumps such as P-glycoprotein (P-gp/ABCB1), multidrug resistance-associated protein 1 (MRP1/ABCC1) and breast cancer resistance protein (BCRP/ABCG2) are overexpressed in cancer cells. (2). The overexpression of ABC transporters in cancer cells are responsible for drug resistance because they pump a variety of anticancer drugs out of cells at the expense of ATP hydrolysis (3). In this study we explored monensis, valinomicin and nigericin ionophore antibiotics influence to wild-type breast carcinoma cell line (MX-1wt), human gingival fibroblasts (HGFwt) and Chinese hamster ovary epithelial cell line (CHOwt) viability. The aim: to analyse MDR efflux pumps activity on cancer and somatic cells and investigate the influence of ionophore antibiotics on breast cancer and somatic cells viability. Methods. The levels of resistance to monensin, nigericin and valinomycin were rated in MX-1wt, MX-1T128, HGFwt and CHOwt cells lines using MTT viability test. The functional activity of MDR pumps in cell lines was measured by using spectrophotometric method – fluorescence. Results. In this study we derived new cell subline with resistance to 128 μM of tetraphenylphosphonium (MX-1T128). In all cell lines the activity of efflux pumps is different. were sensitive to ionophore antibiotics. Ionophore antibiotics influence the viability of wild-type cell lines. Conclusion. The highest activity of MDR efflux pumps is in MX-1T128 cell subline and the lowest - in HGF wt cells. Ionophore antibiotics does not affect cancer cells specifically and viability significant decrease in both, somatic and cancer cells linesBiochemijos katedraGamtos mokslų fakultetasLietuvos sveikatos mokslų universitetas. Medicinos akademijaVytauto Didžiojo universiteta

Many berry species are known for their excellent flavor and abundance of healthy compounds posses... more Many berry species are known for their excellent flavor and abundance of healthy compounds possessing antioxidant and other beneficial properties. However, due to a rapid decay after harvesting, the majority of berry crops are processed into juices and other products. Pressing of juice results in large quantities of by-products, called pomace, press-cake or marc. These residues contain various valuable compounds such as polyphenolics, vitamins; however, currently they are used rather inefficiently and in many cases wasted, mainly due to a lack of scientific and technological valorization of their processing methods. This study provides examples of biorefining of black currant (Ribes nigrum), chokeberry (Aronia melanocarpa), raspberry (Rubus idaeus) and European cranberry bush berry (Viburnum opulus) pomaces into high-value functional ingredients by using high pressure and enzyme-assisted extraction/fractionation methods. The residues are further extracted by using pressurized liquids, e.g. water or its mixtures with ethanol while remaining nonsoluble substances are treated with various enzymes to obtain additional water soluble products. The composition and antioxidant properties of the fractions obtained were analysed by chromatography and mass spectrometry while antioxidant properties were evaluated by the batch in vitro assays (DPPH, ABTS, FRAP, ORAC, Folin-Ciocalteu values) and the on-line HPLC-UV-DPPH radical scavenging assay. The results indicate that the fractions isolated from berry pomaces contain valuable bioactive compounds, which might find applications in functional foods, nutraceuticals, cosmetics, and other products. Firstly, lipophilic fractions, consisting mainly of triacylglycerols, were extracted with supercritical carbon dioxide. At optimal conditions, the yields of oily extracts from berries were from 3 to 15 %. These extracts were rich in polyunsaturated fatty acids and tocopherols. Higher polarity fractions were extracted from the residues and the total yield of extracts was up to 80 %. These fractions contained various phytochemicals; most of them were strong antioxidants. Conclusion: the concept of biorefining, which is defined as ‚a sustainable processing of biomass into a spectrum of bio-based products (food, feed, chemicals, materials) and bioenergy (biofuels, power, and/or heat)' may be successfully applied to berry pomaces for the development of high added value functional ingredients; technological and economical aspects of upscaling the processes should be in the focus of future research.

Materials research express, Mar 29, 2017

Photocatalytic properties of anatase and other TiO2 polymorphs are widely researched and applied ... more 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 techniques. Photocatalytic properties of the observed crystalline anatase phase were tested by investigating bleaching of the methylene blue (MB) aqueous solution and by testing Escherichia coli (E. coli) viability after incubation under UV-B irradiation. E. coli viability experiments indicated that there are two mechanisms of E. coli bacteria inactivation. UV irradiation alone causes rapid damage to the outer membrane of E. coli bacteria. The second mechanism of E. coli inactivation is invoked only with synergistic combination of TiO2 and UV. Acting as photocatalyst TiO2 generates active radicals who initiate the chain peroxidation of organic molecules and within 45 min reduce E. coli bacteria viability by nearly 90%.

Bee pollen is one of the most appreciated and oldest natural products, which chemical composition... more Bee pollen is one of the most appreciated and oldest natural products, which chemical composition represents as a source of bioactive compounds that could be used in food industry or medicine [1]. In recent years, biologically active substances of natural origin focused a great interest of fermentation bioprocesses, which have persisted a main possibility in assay to increase a chemical variety or quantity [2]. Most of the bee pollen properties are influenced by considerable amount of phenolic compounds, mainly flavonoids, which is considered as the main reason for its antimicrobial properties [1]. The aim of this research was to determine the effect of fermentation process of bee pollen on its antibacterial and antifungal activity. Previous study shows, that solid-state fermentation of bee pollen increases total flavonoid content [3]. To our knowledge, this is the first study about the evaluation of antibacterial and antifungal activities of fermented bee pollen. Five samples of bee pollen were fermented with L. rhamnosus and L. lactis bacteria for 12 days. Spontaneous fermentation was also performed at the same conditions. Methanolic extracts of fermented and non-fermented bee pollen samples have been tested for antimicrobial activity. The antibacterial activity of bee pollen extracts was evaluated by well diffusion assay against Escherichia coli, Staphylococcus aureus and Micrococcus luteus. The results were expressed as μg of gentamicin equivalent (GEN) per millilitre of extract. The antifungal activity against mould species, namely Penicillium roqueforti and Penicillium camemberti, was also evaluated; results expressed in mm of clear zone radius around the well. The positive effect on antibacterial and antifungal activity of solid-state fermentation was revealed. Antibacterial activity of non-fermented bee pollen samples against M. luteus ranged from 13.46 ± 0.29 μg/ml (GEN) to 27.89 ± 0.29 μg/ml (GEN), against S. aureus-from 11.45 ± 0.29 μg/ml (GEN) to 25.03 ± 0.01 μg/ml (GEN), and against E. coli-from 1.75 ± 0.01 μg/ml (GEN) to 15.88 ± 0.01 μg/ml (GEN). Antifungal activity against different mould species did not show relatively high significant difference in non-fermented samples: against P. camemberti activity varied from 1.50 ± 0.01 mm to 4.50 ± 0.01 mm, against P. Roqueforti-from 3.00 ± 0.01 mm to 6.50 ± 0.01 mm. The antibacterial activity after fermentation increased by 1,6-2 times and the antifungal activity-2-4 times. The results depended on botanical origin of bee pollen, the type of bacteria, which were used for fermentation, and the type of bacteria or fungi, which was used for determination of antimicrobial activity. Acknowledgements: This project was financed by Research Council of Lithuania project No. 09.3.3-LMT-K-712-03-0127.

Many berry species are known for their excellent flavor and abundance of healthy compounds posses... more Many berry species are known for their excellent flavor and abundance of healthy compounds possessing antioxidant and other beneficial properties. However, due to a rapid decay after harvesting, the majority of berry crops are processed into juices and other products. Pressing of juice results in large quantities of by-products, called pomace, press-cake or marc. These residues contain various valuable compounds such as polyphenolics, vitamins; however, currently they are used rather inefficiently and in many cases wasted, mainly due to a lack of scientific and technological valorization of their processing methods. This study provides examples of biorefining of black currant (Ribes nigrum), chokeberry (Aronia melanocarpa), raspberry (Rubus idaeus) and European cranberry bush berry (Viburnum opulus) pomaces into high-value functional ingredients by using high pressure and enzyme-assisted extraction/fractionation methods. The residues are further extracted by using pressurized liquids, e.g. water or its mixtures with ethanol while remaining nonsoluble substances are treated with various enzymes to obtain additional water soluble products. The composition and antioxidant properties of the fractions obtained were analysed by chromatography and mass spectrometry while antioxidant properties were evaluated by the batch in vitro assays (DPPH, ABTS, FRAP, ORAC, Folin-Ciocalteu values) and the on-line HPLC-UV-DPPH radical scavenging assay. The results indicate that the fractions isolated from berry pomaces contain valuable bioactive compounds, which might find applications in functional foods, nutraceuticals, cosmetics, and other products. Firstly, lipophilic fractions, consisting mainly of triacylglycerols, were extracted with supercritical carbon dioxide. At optimal conditions, the yields of oily extracts from berries were from 3 to 15 %. These extracts were rich in polyunsaturated fatty acids and tocopherols. Higher polarity fractions were extracted from the residues and the total yield of extracts was up to 80 %. These fractions contained various phytochemicals; most of them were strong antioxidants. Conclusion: the concept of biorefining, which is defined as ‚a sustainable processing of biomass into a spectrum of bio-based products (food, feed, chemicals, materials) and bioenergy (biofuels, power, and/or heat)' may be successfully applied to berry pomaces for the development of high added value functional ingredients; technological and economical aspects of upscaling the processes should be in the focus of future research.

Lactococcus lactis is one of the most commonly used in the dairy industry lactic acid bacteria [1... more Lactococcus lactis is one of the most commonly used in the dairy industry lactic acid bacteria [1]. Virus infection of these bacteria inhibits lactose conversion to lactic acid. Therefore, quality of the product changes, in some cases the production is stopped. Usually L. lactis is infected by phages belonging to the Siphoviridae family. The aim of this study was to determine the influence of phage c2 and sk1 infection on energetical metabolism of L. lactis cells. It is usual in the dairy industry to inactivate bacteriophages by heat [2], but higher the temperature is, more taste and presentation of the final product is affected. In order to explore the phage inactivation by heat, phage c2 and sk1 suspensions were incubated at 63°C and 90°C for various time periods. The heating considerably affected the courses of infections: after 30 min incubation at 63 °C phage sk1 remained infective, but after 30 min at 90 °C this phage was completely inactivated. The infectivity of phage c2 decreases more than 7 times after 15 min of incubation at 90 °C, and after 60 min the phage c2 was completely inactivated. Also our results shows that these phages do not infect heated L. lactis cells. It is known [3] that the supplement of a medium with divalent cations, such as Ca2+, Mg2+, Mn2+ or Sr2+, is rather often required for the productive infection. Our results indicated that the reproduction of phages c2 and sk1 also does not occur if the growth medium is not supplemented with these ions. Also our results have shown that these phages weakly adsorb on L. lactis cells without Ca2+ supplement. Examination of the respiration process have shown that if cells are uninfected, they actively respire and use all the oxygen from the medium. Once the phages c2 or sk1 begins to disrupt cells, the dissolved oxygen concentration in medium gradually increases. Usually L. lactis starter cultures are freeze-dried or spray-dried.[...]Biochemijos katedraGamtos mokslų fakultetasVytauto Didžiojo universiteta

Background. Multidrug resistance (MDR) is a significant problem that determine failures of chemot... more Background. Multidrug resistance (MDR) is a significant problem that determine failures of chemotherapy of human malignancies. The main mechanism of MDR is ATP-binding cassette (ABC) efflux transporters that exist in all living cells (1). The biggest problem is that ABC efflux pumps such as P-glycoprotein (P-gp/ABCB1), multidrug resistance-associated protein 1 (MRP1/ABCC1) and breast cancer resistance protein (BCRP/ABCG2) are overexpressed in cancer cells. (2). The overexpression of ABC transporters in cancer cells are responsible for drug resistance because they pump a variety of anticancer drugs out of cells at the expense of ATP hydrolysis (3). In this study we explored monensis, valinomicin and nigericin ionophore antibiotics influence to wild-type breast carcinoma cell line (MX-1wt), human gingival fibroblasts (HGFwt) and Chinese hamster ovary epithelial cell line (CHOwt) viability. The aim: to analyse MDR efflux pumps activity on cancer and somatic cells and investigate the influence of ionophore antibiotics on breast cancer and somatic cells viability. Methods. The levels of resistance to monensin, nigericin and valinomycin were rated in MX-1wt, MX-1T128, HGFwt and CHOwt cells lines using MTT viability test. The functional activity of MDR pumps in cell lines was measured by using spectrophotometric method – fluorescence. Results. In this study we derived new cell subline with resistance to 128 μM of tetraphenylphosphonium (MX-1T128). In all cell lines the activity of efflux pumps is different. were sensitive to ionophore antibiotics. Ionophore antibiotics influence the viability of wild-type cell lines. Conclusion. The highest activity of MDR efflux pumps is in MX-1T128 cell subline and the lowest - in HGF wt cells. Ionophore antibiotics does not affect cancer cells specifically and viability significant decrease in both, somatic and cancer cells linesBiochemijos katedraGamtos mokslų fakultetasLietuvos sveikatos mokslų universitetas. Medicinos akademijaVytauto Didžiojo universiteta

Antimicrobial resistance is a constantly growing worldwide problem. A key part of antimicrobial r... more Antimicrobial resistance is a constantly growing worldwide problem. A key part of antimicrobial resistance is multidrug resistance efflux pumps. Because of these pumps Listeria monocytogenes is a multidrug resistant pathogen, not sensitive to many antimicrobial compounds. It is very important to understand the mechanisms how could we regulate the activity of efflux pumps, because L. monocytogenes is an opportunistic foodborne Gram-positive pathogen causing serious human infections. It is not easy to develop new antimicrobial compounds which would not be a substrate of efflux pumps in addition the sides effects of new compounds are unknown so the knowledge about the inhibition of antibiotics efflux out of cells could increase the effectiveness of treatment. Materials and methods. We used potentiometric and fluorescence methods to assay the inhibition of L. monocytogenes efflux pumps. We used tetraphenylphosphonium, which is a substrate of these pumps, selective electrode to register the inhibition of efflux. In parallel, the intensity of ethidium fluorescence was determined. We used inhibitors of different families of efflux pumps, such as chlorpromazine, verapamil, reserpine. Also we explored the effect of Phe-Arg-β-naphthylamide (PAβN) and 1-(1-Naphthylmethyl)piperazine which have not yet been used against gram-positive bacteria. The aim. The aim of our studies was to determine the specificities of tetraphenylphosphonium and ethidium interaction with L. monocytogenes cells and to evaluate the efficiency of efflux pumps inhibition. Conclusions. TPP+ strongly inhibits the intensity of respiration of L. monocytogenes cells while ethidium – not. We determined that all of used inhibitors increase the accumulation of efflux pumps substrate. In addition, we observed that PAβN and NMP inhibit the efflux of tetraphenylphosphonium but not ethidium. [...]Biochemijos katedraGamtos mokslų fakultetasVytauto Didžiojo universiteta

Chemia i Inżynieria Ekologiczna, 2002

Veterinarija Ir Zootechnika, 2009

Veterinarski Arhiv, Oct 26, 2009

105 isolates of 105 isolates of Enterococcus Enterococcus spp. were selected as representative sa... more 105 isolates of 105 isolates of Enterococcus Enterococcus spp. were selected as representative samples from different herds of pigs (n=25), 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 cattle (n=46) and poultry (n=34). Antimicrobial susceptibility was determined according to epidemiological cutoff values. The highest number of strains demonstrated epidemiological resistance to lincomycin (78%), cutoff values. The highest number of strains demonstrated epidemiological resistance to lincomycin (78%), tetracycline, (65%), fl avomycin (59%) and erythromycin (55%). The smallest number of strains was resistant tetracycline, (65%), fl avomycin (59%) and erythromycin (55%). The smallest number of strains was resistant to linezolid (1%) and tigecycline (2%). Six percent of all tested strains were epidemiologically resistant to to linezolid (1%) and tigecycline (2%). Six percent of all tested strains were epidemiologically resistant to ciprofl oxacin, vancomycin and daptomycin. ciprofl oxacin, vancomycin and daptomycin. Cattle isolates showed the most frequent resistance to fl avomycin (71%), lincomycin (54%), tetracycline (45%), streptomycin (40%) and erythromycin (40%). Enterococci isolated from pigs showed the highest resistance to tetracycline and lincomycin (92%), erythromycin (76%), kanamycin (56%) and streptomycin (52%). All strains isolated from poultry were epidemiologically resistant to lincomycin. The most frequent resistance of poultry strains was also demonstrated to tetracycline (72%), erythromycin (63%), streptomycin (50%), fl avomycin (48%) and tylosin (47%). However all strains isolated from poultry were susceptible to chloramphenicol, quinupristin/dalfopristin, linezolid and bacitracin.

Biochimica Et Biophysica Acta - Bioenergetics, Oct 1, 2012

Inorganics (Basel), Jan 26, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

The study aimed to test laser speckle contrast imaging for fast and non-invasive assessment of ul... more The study aimed to test laser speckle contrast imaging for fast and non-invasive assessment of ultrasound induced bactericidal effect on C. albicans biofilm. Low frequency sonication applied at 1.1 MPa peak negative pressure for 1 min reduced the number of viable C. albicans cells. The bactericidal effect was related to the spectral contrast decrease resulting from the standard deviation decrease within the speckle pattern as compared to the unchanged mean intensity. C. albicans biofilm recovered completely within 41 h after sonication. The recovery of biofilm was represented by increase of speckle contrast parameter. We foresee that speckle-based technique would be helpful for the efficacy assay of microbial biofilm inactivation.

Environmental and Climate Technologies, 2021

A lot of human activities have negative impact on water quality and sometimes result in the biolo... more 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 photocatalyst activated advanced oxidation processes. One of the most studied photocatalysts which attracts a lot of research interest is titanium dioxide. TiO2 application for the disinfection of water, air or surfaces is increasingly encouraged by researchers. However, to unlock its full potential it is highly desirable to make it suitable for the visible light activation. In the current study the effect of visible light assisted photocatalytic treatment to the outer membrane permeability of Salmonella enterica bacteria and how it changes under different titanium dioxide concentrations was analysed. The results from the treatment of rel...

Background. Multidrug resistance (MDR) is a significant problem that determine failures of chemot... more Background. Multidrug resistance (MDR) is a significant problem that determine failures of chemotherapy of human malignancies. The main mechanism of MDR is ATP-binding cassette (ABC) efflux transporters that exist in all living cells (1). The biggest problem is that ABC efflux pumps such as P-glycoprotein (P-gp/ABCB1), multidrug resistance-associated protein 1 (MRP1/ABCC1) and breast cancer resistance protein (BCRP/ABCG2) are overexpressed in cancer cells. (2). The overexpression of ABC transporters in cancer cells are responsible for drug resistance because they pump a variety of anticancer drugs out of cells at the expense of ATP hydrolysis (3). In this study we explored monensis, valinomicin and nigericin ionophore antibiotics influence to wild-type breast carcinoma cell line (MX-1wt), human gingival fibroblasts (HGFwt) and Chinese hamster ovary epithelial cell line (CHOwt) viability. The aim: to analyse MDR efflux pumps activity on cancer and somatic cells and investigate the influence of ionophore antibiotics on breast cancer and somatic cells viability. Methods. The levels of resistance to monensin, nigericin and valinomycin were rated in MX-1wt, MX-1T128, HGFwt and CHOwt cells lines using MTT viability test. The functional activity of MDR pumps in cell lines was measured by using spectrophotometric method – fluorescence. Results. In this study we derived new cell subline with resistance to 128 μM of tetraphenylphosphonium (MX-1T128). In all cell lines the activity of efflux pumps is different. were sensitive to ionophore antibiotics. Ionophore antibiotics influence the viability of wild-type cell lines. Conclusion. The highest activity of MDR efflux pumps is in MX-1T128 cell subline and the lowest - in HGF wt cells. Ionophore antibiotics does not affect cancer cells specifically and viability significant decrease in both, somatic and cancer cells linesBiochemijos katedraGamtos mokslų fakultetasLietuvos sveikatos mokslų universitetas. Medicinos akademijaVytauto Didžiojo universiteta

Many berry species are known for their excellent flavor and abundance of healthy compounds posses... more Many berry species are known for their excellent flavor and abundance of healthy compounds possessing antioxidant and other beneficial properties. However, due to a rapid decay after harvesting, the majority of berry crops are processed into juices and other products. Pressing of juice results in large quantities of by-products, called pomace, press-cake or marc. These residues contain various valuable compounds such as polyphenolics, vitamins; however, currently they are used rather inefficiently and in many cases wasted, mainly due to a lack of scientific and technological valorization of their processing methods. This study provides examples of biorefining of black currant (Ribes nigrum), chokeberry (Aronia melanocarpa), raspberry (Rubus idaeus) and European cranberry bush berry (Viburnum opulus) pomaces into high-value functional ingredients by using high pressure and enzyme-assisted extraction/fractionation methods. The residues are further extracted by using pressurized liquids, e.g. water or its mixtures with ethanol while remaining nonsoluble substances are treated with various enzymes to obtain additional water soluble products. The composition and antioxidant properties of the fractions obtained were analysed by chromatography and mass spectrometry while antioxidant properties were evaluated by the batch in vitro assays (DPPH, ABTS, FRAP, ORAC, Folin-Ciocalteu values) and the on-line HPLC-UV-DPPH radical scavenging assay. The results indicate that the fractions isolated from berry pomaces contain valuable bioactive compounds, which might find applications in functional foods, nutraceuticals, cosmetics, and other products. Firstly, lipophilic fractions, consisting mainly of triacylglycerols, were extracted with supercritical carbon dioxide. At optimal conditions, the yields of oily extracts from berries were from 3 to 15 %. These extracts were rich in polyunsaturated fatty acids and tocopherols. Higher polarity fractions were extracted from the residues and the total yield of extracts was up to 80 %. These fractions contained various phytochemicals; most of them were strong antioxidants. Conclusion: the concept of biorefining, which is defined as ‚a sustainable processing of biomass into a spectrum of bio-based products (food, feed, chemicals, materials) and bioenergy (biofuels, power, and/or heat)' may be successfully applied to berry pomaces for the development of high added value functional ingredients; technological and economical aspects of upscaling the processes should be in the focus of future research.

Materials research express, Mar 29, 2017

Photocatalytic properties of anatase and other TiO2 polymorphs are widely researched and applied ... more 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 techniques. Photocatalytic properties of the observed crystalline anatase phase were tested by investigating bleaching of the methylene blue (MB) aqueous solution and by testing Escherichia coli (E. coli) viability after incubation under UV-B irradiation. E. coli viability experiments indicated that there are two mechanisms of E. coli bacteria inactivation. UV irradiation alone causes rapid damage to the outer membrane of E. coli bacteria. The second mechanism of E. coli inactivation is invoked only with synergistic combination of TiO2 and UV. Acting as photocatalyst TiO2 generates active radicals who initiate the chain peroxidation of organic molecules and within 45 min reduce E. coli bacteria viability by nearly 90%.

Bee pollen is one of the most appreciated and oldest natural products, which chemical composition... more Bee pollen is one of the most appreciated and oldest natural products, which chemical composition represents as a source of bioactive compounds that could be used in food industry or medicine [1]. In recent years, biologically active substances of natural origin focused a great interest of fermentation bioprocesses, which have persisted a main possibility in assay to increase a chemical variety or quantity [2]. Most of the bee pollen properties are influenced by considerable amount of phenolic compounds, mainly flavonoids, which is considered as the main reason for its antimicrobial properties [1]. The aim of this research was to determine the effect of fermentation process of bee pollen on its antibacterial and antifungal activity. Previous study shows, that solid-state fermentation of bee pollen increases total flavonoid content [3]. To our knowledge, this is the first study about the evaluation of antibacterial and antifungal activities of fermented bee pollen. Five samples of bee pollen were fermented with L. rhamnosus and L. lactis bacteria for 12 days. Spontaneous fermentation was also performed at the same conditions. Methanolic extracts of fermented and non-fermented bee pollen samples have been tested for antimicrobial activity. The antibacterial activity of bee pollen extracts was evaluated by well diffusion assay against Escherichia coli, Staphylococcus aureus and Micrococcus luteus. The results were expressed as μg of gentamicin equivalent (GEN) per millilitre of extract. The antifungal activity against mould species, namely Penicillium roqueforti and Penicillium camemberti, was also evaluated; results expressed in mm of clear zone radius around the well. The positive effect on antibacterial and antifungal activity of solid-state fermentation was revealed. Antibacterial activity of non-fermented bee pollen samples against M. luteus ranged from 13.46 ± 0.29 μg/ml (GEN) to 27.89 ± 0.29 μg/ml (GEN), against S. aureus-from 11.45 ± 0.29 μg/ml (GEN) to 25.03 ± 0.01 μg/ml (GEN), and against E. coli-from 1.75 ± 0.01 μg/ml (GEN) to 15.88 ± 0.01 μg/ml (GEN). Antifungal activity against different mould species did not show relatively high significant difference in non-fermented samples: against P. camemberti activity varied from 1.50 ± 0.01 mm to 4.50 ± 0.01 mm, against P. Roqueforti-from 3.00 ± 0.01 mm to 6.50 ± 0.01 mm. The antibacterial activity after fermentation increased by 1,6-2 times and the antifungal activity-2-4 times. The results depended on botanical origin of bee pollen, the type of bacteria, which were used for fermentation, and the type of bacteria or fungi, which was used for determination of antimicrobial activity. Acknowledgements: This project was financed by Research Council of Lithuania project No. 09.3.3-LMT-K-712-03-0127.

Many berry species are known for their excellent flavor and abundance of healthy compounds posses... more Many berry species are known for their excellent flavor and abundance of healthy compounds possessing antioxidant and other beneficial properties. However, due to a rapid decay after harvesting, the majority of berry crops are processed into juices and other products. Pressing of juice results in large quantities of by-products, called pomace, press-cake or marc. These residues contain various valuable compounds such as polyphenolics, vitamins; however, currently they are used rather inefficiently and in many cases wasted, mainly due to a lack of scientific and technological valorization of their processing methods. This study provides examples of biorefining of black currant (Ribes nigrum), chokeberry (Aronia melanocarpa), raspberry (Rubus idaeus) and European cranberry bush berry (Viburnum opulus) pomaces into high-value functional ingredients by using high pressure and enzyme-assisted extraction/fractionation methods. The residues are further extracted by using pressurized liquids, e.g. water or its mixtures with ethanol while remaining nonsoluble substances are treated with various enzymes to obtain additional water soluble products. The composition and antioxidant properties of the fractions obtained were analysed by chromatography and mass spectrometry while antioxidant properties were evaluated by the batch in vitro assays (DPPH, ABTS, FRAP, ORAC, Folin-Ciocalteu values) and the on-line HPLC-UV-DPPH radical scavenging assay. The results indicate that the fractions isolated from berry pomaces contain valuable bioactive compounds, which might find applications in functional foods, nutraceuticals, cosmetics, and other products. Firstly, lipophilic fractions, consisting mainly of triacylglycerols, were extracted with supercritical carbon dioxide. At optimal conditions, the yields of oily extracts from berries were from 3 to 15 %. These extracts were rich in polyunsaturated fatty acids and tocopherols. Higher polarity fractions were extracted from the residues and the total yield of extracts was up to 80 %. These fractions contained various phytochemicals; most of them were strong antioxidants. Conclusion: the concept of biorefining, which is defined as ‚a sustainable processing of biomass into a spectrum of bio-based products (food, feed, chemicals, materials) and bioenergy (biofuels, power, and/or heat)' may be successfully applied to berry pomaces for the development of high added value functional ingredients; technological and economical aspects of upscaling the processes should be in the focus of future research.

Lactococcus lactis is one of the most commonly used in the dairy industry lactic acid bacteria [1... more Lactococcus lactis is one of the most commonly used in the dairy industry lactic acid bacteria [1]. Virus infection of these bacteria inhibits lactose conversion to lactic acid. Therefore, quality of the product changes, in some cases the production is stopped. Usually L. lactis is infected by phages belonging to the Siphoviridae family. The aim of this study was to determine the influence of phage c2 and sk1 infection on energetical metabolism of L. lactis cells. It is usual in the dairy industry to inactivate bacteriophages by heat [2], but higher the temperature is, more taste and presentation of the final product is affected. In order to explore the phage inactivation by heat, phage c2 and sk1 suspensions were incubated at 63°C and 90°C for various time periods. The heating considerably affected the courses of infections: after 30 min incubation at 63 °C phage sk1 remained infective, but after 30 min at 90 °C this phage was completely inactivated. The infectivity of phage c2 decreases more than 7 times after 15 min of incubation at 90 °C, and after 60 min the phage c2 was completely inactivated. Also our results shows that these phages do not infect heated L. lactis cells. It is known [3] that the supplement of a medium with divalent cations, such as Ca2+, Mg2+, Mn2+ or Sr2+, is rather often required for the productive infection. Our results indicated that the reproduction of phages c2 and sk1 also does not occur if the growth medium is not supplemented with these ions. Also our results have shown that these phages weakly adsorb on L. lactis cells without Ca2+ supplement. Examination of the respiration process have shown that if cells are uninfected, they actively respire and use all the oxygen from the medium. Once the phages c2 or sk1 begins to disrupt cells, the dissolved oxygen concentration in medium gradually increases. Usually L. lactis starter cultures are freeze-dried or spray-dried.[...]Biochemijos katedraGamtos mokslų fakultetasVytauto Didžiojo universiteta

Background. Multidrug resistance (MDR) is a significant problem that determine failures of chemot... more Background. Multidrug resistance (MDR) is a significant problem that determine failures of chemotherapy of human malignancies. The main mechanism of MDR is ATP-binding cassette (ABC) efflux transporters that exist in all living cells (1). The biggest problem is that ABC efflux pumps such as P-glycoprotein (P-gp/ABCB1), multidrug resistance-associated protein 1 (MRP1/ABCC1) and breast cancer resistance protein (BCRP/ABCG2) are overexpressed in cancer cells. (2). The overexpression of ABC transporters in cancer cells are responsible for drug resistance because they pump a variety of anticancer drugs out of cells at the expense of ATP hydrolysis (3). In this study we explored monensis, valinomicin and nigericin ionophore antibiotics influence to wild-type breast carcinoma cell line (MX-1wt), human gingival fibroblasts (HGFwt) and Chinese hamster ovary epithelial cell line (CHOwt) viability. The aim: to analyse MDR efflux pumps activity on cancer and somatic cells and investigate the influence of ionophore antibiotics on breast cancer and somatic cells viability. Methods. The levels of resistance to monensin, nigericin and valinomycin were rated in MX-1wt, MX-1T128, HGFwt and CHOwt cells lines using MTT viability test. The functional activity of MDR pumps in cell lines was measured by using spectrophotometric method – fluorescence. Results. In this study we derived new cell subline with resistance to 128 μM of tetraphenylphosphonium (MX-1T128). In all cell lines the activity of efflux pumps is different. were sensitive to ionophore antibiotics. Ionophore antibiotics influence the viability of wild-type cell lines. Conclusion. The highest activity of MDR efflux pumps is in MX-1T128 cell subline and the lowest - in HGF wt cells. Ionophore antibiotics does not affect cancer cells specifically and viability significant decrease in both, somatic and cancer cells linesBiochemijos katedraGamtos mokslų fakultetasLietuvos sveikatos mokslų universitetas. Medicinos akademijaVytauto Didžiojo universiteta

Antimicrobial resistance is a constantly growing worldwide problem. A key part of antimicrobial r... more Antimicrobial resistance is a constantly growing worldwide problem. A key part of antimicrobial resistance is multidrug resistance efflux pumps. Because of these pumps Listeria monocytogenes is a multidrug resistant pathogen, not sensitive to many antimicrobial compounds. It is very important to understand the mechanisms how could we regulate the activity of efflux pumps, because L. monocytogenes is an opportunistic foodborne Gram-positive pathogen causing serious human infections. It is not easy to develop new antimicrobial compounds which would not be a substrate of efflux pumps in addition the sides effects of new compounds are unknown so the knowledge about the inhibition of antibiotics efflux out of cells could increase the effectiveness of treatment. Materials and methods. We used potentiometric and fluorescence methods to assay the inhibition of L. monocytogenes efflux pumps. We used tetraphenylphosphonium, which is a substrate of these pumps, selective electrode to register the inhibition of efflux. In parallel, the intensity of ethidium fluorescence was determined. We used inhibitors of different families of efflux pumps, such as chlorpromazine, verapamil, reserpine. Also we explored the effect of Phe-Arg-β-naphthylamide (PAβN) and 1-(1-Naphthylmethyl)piperazine which have not yet been used against gram-positive bacteria. The aim. The aim of our studies was to determine the specificities of tetraphenylphosphonium and ethidium interaction with L. monocytogenes cells and to evaluate the efficiency of efflux pumps inhibition. Conclusions. TPP+ strongly inhibits the intensity of respiration of L. monocytogenes cells while ethidium – not. We determined that all of used inhibitors increase the accumulation of efflux pumps substrate. In addition, we observed that PAβN and NMP inhibit the efflux of tetraphenylphosphonium but not ethidium. [...]Biochemijos katedraGamtos mokslų fakultetasVytauto Didžiojo universiteta

Chemia i Inżynieria Ekologiczna, 2002

Veterinarija Ir Zootechnika, 2009

Veterinarski Arhiv, Oct 26, 2009

105 isolates of 105 isolates of Enterococcus Enterococcus spp. were selected as representative sa... more 105 isolates of 105 isolates of Enterococcus Enterococcus spp. were selected as representative samples from different herds of pigs (n=25), 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 cattle (n=46) and poultry (n=34). Antimicrobial susceptibility was determined according to epidemiological cutoff values. The highest number of strains demonstrated epidemiological resistance to lincomycin (78%), cutoff values. The highest number of strains demonstrated epidemiological resistance to lincomycin (78%), tetracycline, (65%), fl avomycin (59%) and erythromycin (55%). The smallest number of strains was resistant tetracycline, (65%), fl avomycin (59%) and erythromycin (55%). The smallest number of strains was resistant to linezolid (1%) and tigecycline (2%). Six percent of all tested strains were epidemiologically resistant to to linezolid (1%) and tigecycline (2%). Six percent of all tested strains were epidemiologically resistant to ciprofl oxacin, vancomycin and daptomycin. ciprofl oxacin, vancomycin and daptomycin. Cattle isolates showed the most frequent resistance to fl avomycin (71%), lincomycin (54%), tetracycline (45%), streptomycin (40%) and erythromycin (40%). Enterococci isolated from pigs showed the highest resistance to tetracycline and lincomycin (92%), erythromycin (76%), kanamycin (56%) and streptomycin (52%). All strains isolated from poultry were epidemiologically resistant to lincomycin. The most frequent resistance of poultry strains was also demonstrated to tetracycline (72%), erythromycin (63%), streptomycin (50%), fl avomycin (48%) and tylosin (47%). However all strains isolated from poultry were susceptible to chloramphenicol, quinupristin/dalfopristin, linezolid and bacitracin.

Biochimica Et Biophysica Acta - Bioenergetics, Oct 1, 2012

Inorganics (Basel), Jan 26, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

The study aimed to test laser speckle contrast imaging for fast and non-invasive assessment of ul... more The study aimed to test laser speckle contrast imaging for fast and non-invasive assessment of ultrasound induced bactericidal effect on C. albicans biofilm. Low frequency sonication applied at 1.1 MPa peak negative pressure for 1 min reduced the number of viable C. albicans cells. The bactericidal effect was related to the spectral contrast decrease resulting from the standard deviation decrease within the speckle pattern as compared to the unchanged mean intensity. C. albicans biofilm recovered completely within 41 h after sonication. The recovery of biofilm was represented by increase of speckle contrast parameter. We foresee that speckle-based technique would be helpful for the efficacy assay of microbial biofilm inactivation.

Environmental and Climate Technologies, 2021

A lot of human activities have negative impact on water quality and sometimes result in the biolo... more 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 photocatalyst activated advanced oxidation processes. One of the most studied photocatalysts which attracts a lot of research interest is titanium dioxide. TiO2 application for the disinfection of water, air or surfaces is increasingly encouraged by researchers. However, to unlock its full potential it is highly desirable to make it suitable for the visible light activation. In the current study the effect of visible light assisted photocatalytic treatment to the outer membrane permeability of Salmonella enterica bacteria and how it changes under different titanium dioxide concentrations was analysed. The results from the treatment of rel...