Search results for " lichens"
showing 7 items of 17 documents
Eukaryotes Are a Holophyletic Group of Polyphyletic Origin.
2020
Because of the polyphyletic origin of the eukaryotic monophylum, eukaryogenesis within prokaryotes is not comparable with mammal origin within paraphyletic reptiles. Both synapomorphies and plesiomorphies represent apomorphies and are indeed suitable for defining monophyletic (holophyletic and paraphyletic) groups. Alphaproteobacteria (Bacteria) and Asgard (Archaea) are the ancestors of LECA (the Last Eukaryotic Common Ancestor). The presence of ESPs in Asgard does not dispute the polyphyletic origin of eukaryotes ; it only further corroborates it. “Candidatus Prometheoarchaeum syntrophicum” is the closest relative to eukaryotes and the only Asgard with available microscopy data. This newly…
The activity concentration of post-Chernobyl Cs in the area of the Opole Anomaly (southern Poland)
2015
During the years 2007 and 2010, the activity concentration of 137Cs accumulated in soil, mosses Pleurozium schreberi and lichens Hypogymnia physodes was measured. The studies covered the areas of the so-called Opole Anomaly. In consequence of the Chernobyl nuclear power plant breakdown in 1986, relatively large amounts of this radionuclide were deposited in this area. In some areas of the Anomaly, over 100 times higher surface activity of 137Cs was detected, compared to the lowest values registered in Poland. Currently, 137Cs is still present in woodlands and wastelands. As at 2 April 2013, the surface activity concentration of 137Cs in soil on the tested area was from 0.34 to 67.5 kBq m−2.…
Background element content in the lichen Pseudevernia furfuracea: a comparative analysis of digestion methods
2019
In bioaccumulation studies, the interpretation of pollutant contents in the target biomonitor has to be performed by assessing a deviation from an unaltered reference condition. A common strategy consists in the comparison with background element content (BEC) values, often built up by uncritically merging methodologically heterogeneous data. In this respect, the acid digestion of samples was identified as a major step affecting BEC data. Here, the analytical outcomes of two acid mixtures were compared on a set of matched paired samples of the lichen Pseudevernia furfuracea, a widely used biomonitor for which BEC values based on partial digestion were previously provided. The standard refer…
Background element content of the lichen Pseudevernia furfuracea: A supra-national state of art implemented by novel field data from Italy
2018
Abstract In biomonitoring, the knowledge of background element content (BEC) values is an essential pre-requisite for the correct assessment of pollution levels. Here, we estimated the BEC values of a highly performing biomonitor, the epiphytic lichen Pseudevernia furfuracea, by means of a careful review of literature data, integrated by an extensive field survey. Methodologically homogeneous element content datasets, reflecting different exposure conditions across European and extra-European countries, were compiled and comparatively analysed. Element content in samples collected in remote areas was compared to that of potentially enriched samples, testing differences between medians for 2…
New Interpretative Scales for Lichen Bioaccumulation Data: The Italian Proposal
2019
The interpretation of lichen bioaccumulation data is of paramount importance in environmental forensics and decision-making processes. By implementing basic ideas underlying previous interpretative scales, new dimensionless, species-independent &ldquo
Presence of multiple group I introns closely related to bacteria and fungi in plastid 23S rRNAs of lichen-forming Trebouxia
2009
The chloroplast-encoded large subunit ribosomal RNA gene of several free-living green algae contains group I introns at Escherichia coli genic positions 1917, 1931, 1951, and 2449. Herein we report the presence of group I introns at these positions within the chloroplast-encoded large subunit ribosomal RNA gene of several lichen-forming green algae belonging to the Trebouxia genus. In contrast to the introns inserted at position 2449, all introns inserted at positions 1917, 1931, and 1951 contained LAGLIDADG homing endonuclease genes. Phylogenetic analyses show that: (i) introns inserted at positions 1917, 1931, and 1951 are closely related to introns located at homologous insertion sites i…
Biological Monitoring Using Lichens as a Source of Information About Contamination of Mountain with Heavy Metals
2022
Abstract The aim of this study was passive biomonitoring of the mountains of southern Poland. Lichens Hypogymnia physodes were used for the study. Concentrations of the heavy metals Ni, Cu, Zn, Cd and Pb were determined in these lichens. The concentrations were measured by atomic absorption spectrometry (AAS). The analysis of the concentrations of the determined heavy metals in the lichen thallus allowed to determine the places with the highest and the lowest contamination with a given heavy metal in the study area. It was shown that the area of Great Czantoria and Big Soszow is the most contaminated with heavy metals among the investigated areas. The study shows that the transport of analy…