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In this study, we examined the effect of polychlorinated biphenyls (PCBs) in the presence of natural and synthetic terpenes and biphenyl on biomass production, lipid accumulation, and membrane adaptation mechanisms of two PCB-degrading bacterial strains Pseudomonas stutzeri and Burkholderia xenovorans LB400. According to the results obtained, it could be concluded that natural terpenes, mainly those contained in ivy leaves and pine needles, decreased adaptation responses induced by PCBs in these strains. The adaptation processes under investigation included growth inhibition, lipid accumulation, composition of fatty acids, cis/trans isomerization, and membrane saturation. Growth inhibition effect decreased upon addition of these natural compounds to the medium. The amount of unsaturated fatty acids that can lead to elevated membrane fluidity increased in both strains after the addition of the two natural terpene sources. The cells adaptation changes were more prominent in the presence of carvone, limonene, and biphenyl than in the presence of natural terpenes, as indicated by growth inhibition, lipid accumulation, and cis/trans isomerization. Addition of biphenyl and carvone simultaneously with PCBs increased the trans/cis ratio of fatty acids in membrane fractions probably as a result of fluidizing effects of PCBs. This stimulation is more pronounced in the presence of PCBs as a sole carbon source. This suggests that PCBs alone have a stronger effect on bacterial membrane adaptation mechanisms than when added together with biphenyl or natural or synthetic terpenes.

This study was focused on the characterization of 15 bacterial strains isolated from long-term PCB-contaminated sediment located at the Strážsky canal in eastern part of Slovakia, in the surroundings of a former PCB producer. PCB-degrading strains were isolated and identified as Microbacterium oleivorans, Stenotrophomonas maltophilia, Brevibacterium sp., Ochrobactrum anthropi, Pseudomonas mandelii, Rhodococcus sp., Achromobacter xylosoxidans, Stenotrophomonas sp., Ochrobactrum sp., Pseudomonas aeruginosa, and Starkeya novella by the 16S rRNA gene sequence phylogenetic analysis. This study presents a newly isolated bacterial strain S. novella with PCB-degrading ability in liquid medium as well as in sediment. For A. xylosoxidans, the bphA gene was identified. The best growth ability in the presence of all sole carbon sources (biphenyl and PCBs vapor) was obtained for Ochrobactrum sp. and Rhodococcus sp. Uncultured Achromobacter sp. showed the highest potential for bioaugmentation of PCB-contaminated sediment.

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The paper deals with the application of two perspective and promising bioremediation approaches, bioaugmentation and biostimulation, applied to sediment contaminated with polychlorinated biphenyls (PCBs) with the aim to enhance biodegradation of PCBs. Sediments were sampled from Strážsky canal, an industrial waste canal that flows from a former PCB-factory through the Laborec river into the Zemplínska šírava water reservoir, all located in the eastern part of Slovakia. Bioaugmentation of sediments was performed in microcosms using two bacterial isolates with PCB-degradation ability obtained from the contaminated sediment:

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Th e aim of our study was to examine adolescent personality in relation to the adolescent school-related self-concept, in particular to its cognitive aspect according to W.U. Meyer's conception. In addition to selected personality dimensions, our paper focuses also on gender relations of the adolescent school-related self-concept. Th e research sample was made up of grammar school and university students (N = 100). Th e fi ve-factor model of personality NEO-FFI (P.T. Costa, R.R. McCrae) and SCEA-M questionnaire (U. Engler, W.U. Meyer) were used as research tools. Th e results show a statistically significant relationship between neuroticism and fear of social consequences. Th ere is also a statistically signifi cant relationship between conscientiousness and the self-concept of ability. Statistically signifi cant gender diff erences in favour of women appear in the dimension of fear of social consequences.