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Utilization of 4-n-nonylphenol by Metarhizium sp. isolates

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Różalska S., Pawłowska J., Wrzosek M., Tkaczuk C., Długoński J.
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2013
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vol. 60
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issue 4
677-682
EN
Nonylphenol (4-NP) is a xenobiotic classified as an endocrine disrupting compound with an ability to interfere with hormonal systems of numerous organisms including humans. It is widely distributed not only in aquatic but also in terrestrial systems. The aim of this study was to evaluate the ability of cosmopolitan fungus Metarhizium (commonly persistent in soil as a facultative insect pathogen, controlling populations of arthropods in natural environment) to degrade 4-n-nonylphenol. All isolates examined in this work were identified to a species rank based on five, independent genetic markers. Among eight Metarhizium strains; six of them have been identified as M. robertsii, and two others as M. brunneum and M. lepidiotae. All investigated Metarhzium isolates were found to eliminate 4-n-NP with significant efficiency (initial xenobiotic concentration 50 mg L-1). The degradation process was very effective and at 24h of incubation 50-90% of 4-n-NP was eliminated by certain strains, while extended incubation resulted in further utilization of this compound. At the end of the experiments 64-99% of 4-n-NP was removed from the culture medium. Additionally, in all tested cultures three major metabolites were detected: 4-hydroxybenzoic acid; 2-(4-hydroxyphenyl)acetic acid and 4-hydroxyphenylpentanoic acid. The obtained results indicate that Metarhizium sp. possesses an ability to degrade NP and can serve as a potential candidate for further biodegradation studies.
2
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Effect of nutrient and stress factors on polysaccharides synthesis in Proteus mirabilis biofilm

100%
Moryl M., Kaleta A., Strzelecki K., Różalska S., Różalski A.
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2014
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vol. 61
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issue 1
133-139
EN
The extracellular matrix in biofilm consists of water, proteins, polysaccharides, nucleic acids and phospholipids. Synthesis of these components is influenced by many factors, e.g. environment conditions or carbon source. The aim of the study was to analyse polysaccharides levels in Proteus mirabilis biofilms after exposure to stress and nutritional conditions. Biofilms of 22 P. mirabilis strains were cultivated for 24, 48, 72 hours, 1 and 2 weeks in tryptone soya broth or in modified media containing an additional amount of nutrients (glucose, albumin) or stress factors (cefotaxime, pH 4, nutrient depletion). Proteins and total polysaccharides levels were studied by Lowry and the phenol-sulphuric acid methods, respectively. Glycoproteins levels were calculated by ELLA with the use of selected lectins (WGA and HPA). For CLSM analysis dual fluorescent staining was applied with SYTO 13 and WGA-TRITC. In optimal conditions the levels of polysaccharides were from 0 to 442 μg/mg of protein and differed depending on the strains and cultivation time. The agents used in this study had a significant impact on the polysaccharides synthesis in the P. mirabilis biofilm. Among all studied components (depending on tested methods), glucose and cefotaxime stimulated the greatest production of polysaccharides by P. mirabilis strains (more than a twofold increase). For most tested strains the highest amounts of sugars were detected after one week of incubation. CLSM analysis confirmed the overproduction of N-acetyloglucosamine in biofilms after cultivation in nutrient and stress conditions, with the level 111-1134%, which varied depending on the P. mirabilis strain and the test factor.
3
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Comparative study of metal induced phospholipid modifications in the heavy metal tolerant filamentous fungus Paecilomyces marquandii and implications for the fungal membrane integrity

100%
Słaba M., Bernat P., Różalska S., Nykiel J., Długoński J.
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2013
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vol. 60
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issue 4
695-700
EN
In this work we compared the effect of five heavy metals: Zn, Pb, Cd, Ni and Cu on phospholipid composition of the ubiquitous soil fungus Paecilomyces marquandii, originating from a strongly metal polluted area and characterized by high tolerance to these elements. Cd, Ni and Cu caused an increase in phosphatidylcholine (PC). Only Pb decreased PC content, which was accompanied by a significant rise in the phosphatidic acids (PA) level, probably due to activation of phospholipase D which hydrolyzes PC to PA. This could result in membrane fluidity disturbance, and thus affect its integrity. The assessment of propidium iodide influx showed strong disturbance of membrane integrity for Cu and Pb stressed mycelia, whereas mycelia treated with Ni were impermeable to this dye. The results obtained revealed a strong Cu and Pb toxicity involving disruption of membrane integrity. Pb action was reflected by lipid composition, whereas changes in Cu treated mycelia did not completely elucidate its harmful effect on the membrane, which was most probably caused by Cu induced lipid peroxidation. Zn did not induce quantitative changes in PC and phosphatidylethanolamine (PE) but caused changes in phospholipid lipid saturation, which appears to be important for fungus adaptation to the presence of metals. The enhanced PC content balanced by higher PC saturation can help in the maintenance of proper membrane fluidity and result in alleviating the Cd and Ni induced stress. These results will allow to clarify the mechanism of Pb toxicity and help to elucidate the cellular basis of fungal membrane adaptation to heavy metals.
4
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Antimicrobial, antiadhesive and antibiofilm potential of lipopeptides synthesised by Bacillus subtilis, on uropathogenic bacteria

86%
Moryl M., Spętana M., Dziubek K., Paraszkiewicz K., Różalska S., Płaza G., Różalski A.
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2015
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vol. 62
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issue 4
725-732
EN
The aim of this study was to investigate the antimicrobial effect of lipopeptide biosurfactants from surfactin, iturin and fengycin families, synthesised by the Bacillus subtilis I'1a strain, on uropathogenic bacteria, including the effects on planktonic growth, processes of biofilm formation and dislodging. Antimicrobial activity was tested against 32 uropathogenic strains belonging to 12 different species of Gram-negative and Gram-positive bacteria. The sensitivity of 25 tested bacterial strains to the B. subtilis I'1a filtrate was confirmed by an agar diffusion assay. None of the strains seemed to be sensitive to pure surfactin at concentrations ranging from 0.1 mg × ml-1 to 0.4 mg ml-1. After the treatment of uropathogens with B. subtilis lipopeptides, the metabolic activity of planktonic cells was inhibited by 88.05±3.96% in the case of 21 studied uropathogens, the process of biofilm formation was reduced by 88.15±4.77% in the case of 24 uropathogens and mature biofilms of 18 strains were dislodged by about 81.20±4.72%. Ten strains of uropathogenic bacteria were selected to study the antimicrobial activity of surfactin (concentrations 0.1, 0.2 and 0.4 mg × ml-1). Surfactin had no influence on the metabolic activity of planktonic forms of uropathogens, however, biofilms of 5 tested strains were reduced by 64.77±9.05% in the presence of this biosurfactant at the concentration 0.1 mg × ml-1. The negative effect of the compound on the biofilm formation process was observed at all concentrations used. The above-described results were fully confirmed by CLSM. It could suggest that synergistic application of biosurfactants could be efficient in uropathogen eradication.
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