Jagiellonian University

About: Jagiellonian University is a education organization based out in Krakow, Poland. It is known for research contribution in the topics: Population & Catalysis. The organization has 17438 authors who have published 44092 publications receiving 862633 citations. The organization is also known as: Academia Cracoviensis & Akademia Krakowska.

Identification of arbuscular mycorrhizal fungi in soils and roots of plants colonizing zinc wastes in southern Poland

Abstract: Analysis of the community of arbuscular mycorrhizal (AM) fungi in roots of Fragaria vesca growing in a heavy metal contaminated site was carried out on a Zn waste site near Chrzanow (southern Poland). The waste substratum was characterized by high contents of Pb, Zn, Cd, Cu and As, and by low levels of N, P and organic matter. Spores of Glomales were isolated by wet sieving and DNA was isolated from individual spores. Nested polymerase chain reaction (PCR) with taxon-specific primers was used to identify the species Glomus mosseae, Glomus intraradices and Glomus claroideum. Spores of other fungi were morphologically characterized and new taxon-discriminating molecular probes were developed for two of them (Glomus sp. HM-CL4 and HM-CL5) based on variations in the large ribosomal subunit (25S rDNA). High sequence similarities were found between Glomus sp. HM-CL4 and Glomus gerdemanii, and between Glomus sp. HM-CL5 and Glomus occultum. The designed primers were used to characterize the population of AM fungi colonizing the roots of F. vesca collected from the Zn waste site. The analysis, carried out on roots stained with trypan blue, showed that the most effective colonizer was closely related to G. gerdemannii. G. claroideum and the G. occultum-like fungus were slightly less common whilst frequencies of G. intraradices and G. mosseae in roots were much lower. The analysis of mycorrhiza stained with rhodizoniate to localize heavy metal accumulation showed that the stain does not influence the PCR reaction. Seventy percent of the root samples containing positively stained fungal hyphae were found to be colonized by G. mosseae. The data obtained demonstrate the usefulness of nested PCR for studies carried out in polluted areas. It will enable selection of AM fungi which are able to colonize plant roots under heavy metal stress conditions, as well as the identification of fungi showing high in situ accumulation of potentially toxic elements.

The content of phenolic compounds and radical scavenging activity varies with carrot origin and root color

Abstract: The contents of phenolic compounds and radical scavenging activities were assessed in a carrot collection comprising 35 cultivars, landraces and breeding populations. The accessions originated from various world regions and they represented Eastern and Western carrot gene pools. In two-year field trial carrot roots of orange, red, yellow, white and purple color were cultivated, freeze-dried and analyzed for phenolic content by Folin-Ciocalteu assay and UV/Vis assay. Radical scavenging activity in the extracts was determined with a stable DPPH radical. Carrots developing purple roots possessed on average 9 times more phenolics than roots of other colors. Furthermore, they were rich in anthocyanins that caused very high antiradical activity. Red carrots showed higher antioxidant activity than orange, yellow and white carrots and in the season of lower rainfall they accumulated higher amounts of phenolic compounds. Carrots of Asian origin belonging to Eastern gene pool were more often purple or red and richer in phenolics and had higher antiradical activity than those from the Western gene pool with mainly orange roots.

Carotenoids and environmental stress in plants : Significance of carotenoid-mediated modulation of membrane physical properties

Abstract: Carotenoids, apart of their antenna function in photosynthesis, play an important role in the mechanisms protecting the photosynthetic apparatus against various harmful environmental factors. They protect plants against overexcitation in strong light and dissipate the excess of absorbed energy, they scavenge reactive oxygen species formed during photooxidative stress and moderate the effect of extreme temperatures. One of the important factors involved in the protective action of carotenoids is their influence on the molecular dynamics of membranes. To obtain complex information about interactions between carotenoids and lipids in a membrane, different techniques were used. In this review, the data resulting from EPR–spin label spectrometry, 31P- and 13C-NMR, differential scanning calorimetry, and computer simulation of the membrane molecular dynamics are presented. The effects of selected, structurally different carotenoid species on various physical parameters of model and natural membranes are described and their relevance to protection against some environmental stresses are discussed.

Novel TiO2/C3N4 Photocatalysts for Photocatalytic Reduction of CO2 and for Photocatalytic Decomposition of N2O

Abstract: TiO2/g-C3N4 photocatalysts with the ratio of TiO2 to g-C3N4 ranging from 0.3/1 to 2/1 were prepared by simple mechanical mixing of pure g-C3N4 and commercial TiO2 Evonik P25. All the nanocomposites were characterized by X-ray powder diffraction, UV–vis diffuse reflectance spectroscopy, photoluminescence, X-ray photoelectron spectroscopy, Raman spectroscopy, infrared spectroscopy, transmission electron microscopy, photoelectrochemical measurements, and nitrogen physisorption. The prepared mixtures along with pure TiO2 and g-C3N4 were tested for the photocatalytic reduction of carbon dioxide and photocatalytic decomposition of nitrous oxide. The pure g-C3N4 exhibited the lowest photocatalytic activity in both cases, pointing to a very high recombination rate of charge carriers. On the other hand, the most active photocatalyst toward all the products was (0.3/1)TiO2/g-C3N4. The highest activity is achieved by combination of a number of factors: (i) specific surface area, (ii) adsorption edge energy, (iii) cr...