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Simple Summary Central nervous system (CNS) diseases, including tumors such as glioblastomas and neurodegenerative diseases, such as Alzheimer’s disease, are some of the greatest challenges of modern medicine. Therefore, our study aimed to evaluate the anticancer and neuroprotective activity of the extract from a common European lichen Hypogymnia physodes and of its compound-physodic acid. The examined substances were cytotoxic against the glioblastoma cell lines A-172, T98G, and U-138 MG. Both substances strongly inhibited hyaluronidase, and diminished cyclooxygenase-2 activity (H. physodes extract), enzymes expressed in patients with malignant glioma. Furthermore, H. physodes extract inhibited tyrosinase activity, the enzyme linked to neurodegenerative diseases. The tested substances exhibited antioxidant activity, however, acetylcholinesterase and butyrylcholinesterase inhibitory activity were not high. We proved that physodic acid can cross the blood–brain barrier. We conclude that physodic acid and H. physodes extract should be regarded as promising agents with anticancer, chemopreventive, and neuroprotective activities, especially concerning CNS. Abstract Lichen secondary metabolites are characterized by huge pharmacological potential. Our research focused on assessing the anticancer and neuroprotective activity of Hypogymnia physodes acetone extract (HP extract) and physodic acid, its major component. The antitumor properties were evaluated by cytotoxicity analysis using A-172, T98G, and U-138 MG glioblastoma cell lines and by hyaluronidase and cyclooxygenase-2 (COX-2) inhibition. The neuroprotective potential was examined using COX-2, tyrosinase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) activity tests. Moreover, the antioxidant potential of the tested substances was examined, and the chemical composition of the extract was analyzed. For physodic acid, the permeability through the blood–brain barrier using Parallel Artificial Membrane Permeability Assay for the Blood–Brain Barrier assay (PAMPA-BBB) was assessed. Our study shows that the tested substances strongly inhibited glioblastoma cell proliferation and hyaluronidase activity. Besides, HP extract diminished COX-2 and tyrosinase activity. However, the AChE and BChE inhibitory activity of HP extract and physodic acid were mild. The examined substances exhibited strong antioxidant activity. Importantly, we proved that physodic acid crosses the blood–brain barrier. We conclude that physodic acid and H. physodes should be regarded as promising agents with anticancer, chemopreventive, and neuroprotective activities, especially regarding the central nervous system diseases.

Objective : to study antibacterial properties of Hypogymnia physodes extract and its combinations with antibiotics against vancomycin-sensitive and vancomycin-resistant strains of enterococci. Material and methods. Minimum inhibitory concentrations (MICs) of the acetone extract of H. physodes for reference and clinical isolates of Enterococcus faecalis were determined by the serial broth dilution method. Evaluation of efficiency of the combined effect of the H. physodes extract in combination with antibiotics was carried out using the modified disc-diffusion method and «chessboard» method. Results. We have revealed marked antibacterial activity (MIC 32-64 mcg/ml) of the acetone extract of H. physodes against vancomycin-sensitive and vancomycin-resistant strains of enterococci and found a synergistic effect (ΣFIC from 0.125 to 0.375) of the combination of the H. physodes extract and aminoglycosides against E. faecalis , including vancomycin-resistant strains. Conclusion. H. physodes is a promising source of compounds with antibacterial activity, further research is required to identify and isolate a secondary metabolite having synergistic activity in combination with aminoglycosides from the lichen extract.

Woodlice are not widely recognized as lichen-feeding invertebrates. We sought to discover whether the woodlouse, Porcellio scaber, could feed on the lichen Hypogymnia physodes and if the lichen carbon-based secondary compounds CBSCs would reduce grazing. We cut lichen thalli in two pieces, one was non-destructively rinsed in acetone to remove CBSCs; the other served as a control. Both pieces were fed to woodlice in a choice experiment. The CBSC concentration of individual thalli ranged from 3 to 19%. The woodlice grazed all pieces, but preferred the acetone-rinsed pieces, depending on the amount of CBSCs present in the non-extracted counterpart. The woodlice were not deterred from feeding on samples with CBSC concentrations ≤5%, which corresponded to natural contents in shade-adapted thalli. This suggested that P. scaber tolerates this amount of compounds at least in the short-term. In conclusion, P. scaber can feed on H. physodes, but CBSCs deter them from feeding.

The aim of the study was to assess the metal pollution in the vicinity of the Bukowno smelter near Olkusz in southern Poland. Birch and oak leaves, pine needles and a lichen Hypogymnia physodes, overgrowing pine bark were collected at stands at different distances from the smelter and analysed for cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) content. Concentrations of metals in the lichen were usually higher than in the tree leaves/needles and decreased with distance from the smelter, apart from the Cu content. The strongest correlation was noticed between Cd and Pb concentrations, which indicates a common pollution source (the smelter). Our results show that birch leaves can be potentially useful as a bioindicator of Zn air pollution since this species was shown to accumulate high amounts of zinc, related to environmental pollution with that metal, in their leaves.

Cansaran-Duman, Demet/0000-0001-5662-2333; HAMUTOGLU, RASIM/0000-0002-2474-5336 WOS:000530720800020 This work aims to determine the response of Hypogymnia physodes (L.) Nyl. (hooded tube lichen) collected in an unpolluted site (Yenice Forest in Karabiik, Turkey) to stress conditions. In the present study, the effect of exposure to different heavy metals (Cd+2, Pb+2, and Cr+6) for different durations and UV radiations dosages on lichen was examined at the physiological and molecular levels. The effects of stress conditions were determined in the case of different parameters concerning heavy metal, protein, chlorophyll, and carotenoid contents and changes in the DNA profiles. According to the results obtained that exposure to heavy metals and UV radiations leads to a physiological response in a concentration and dose-dependent manner through differences in chlorophyll, protein content in heavy metals and UV treated lichen specimen. Furthermore, changes in RAPD assay and DNA methylation analysis showed that homologous nucleotide sequences in the genome from untreated and stress conditions treated lichen specimen showed different band patterns and methylation under heavy metals and UV stress. The results determined that lichen specimen suggest as a possible bioindicator able to measure the biological effects of heavy metal pollution and damage to UV radiation. TUBITAK (The Scientific and Technical Research Council of Turkey)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [112T004]; Ankara UniversityAnkara University [13L4240004] We thank TUBITAK (The Scientific and Technical Research Council of Turkey), Project no. 112T004 and Ankara University Project Manager, Project no. 13L4240004 for the financial support.

The contribution of C, N and S, as well as the isotopic composition of C and N of atmospheric pollutants, are assumed to be reflected in the organic compounds inbuilt into the lichen thallus. The chemical and isotopic analyses were carried out on lichen Hypogymnia physodes samples gathered from Picea abies and Larix decidua, collected in 13 sampling points located in Karkonoski National Park and its closest vicinity in 2011. The results for %C, %N and %S varied from 43.44 to 46.79%, from 0.86 to 1.85% and from 0.07 to 0.27 %, respectively. The δ13C values ranged from −26.6 to −24.6‰, whereas δ15N values varied from −13.0 to −6.8‰. The ranges in isotope composition suggest different sources of C and N for Karpacz compared to the remaining sampling sites. For Karpacz, the δ13C values suggest (in case the fractionation product-substrate does not exist and Δ=0) that the dominant sources are coal combustion processes, whereas for remaining sampling points, the δ13C values are ambiguous and are masked by many mixed natural and anthropogenic processes. With the same assumption that Δ=0, the δ15N values suggest that transport is not a dominant source of nitrogen within Karpacz city. Moreover, in this study we tested the possible fractionation (Δ) for carbon and nitrogen, assuming that within the investigated area, the source of carbon is probably CO2 and/or DIC (HCO3 −) dissolved in precipitation, while the source of nitrogen is NOx and/or NO3 − ion. The calculated fractionation factors were: (i) for gaseous carbon compounds ΔCO2-Corg value from −13.4 to −11.4‰, whereas for the ions form ΔHCO3 −-Corg value from −16.6 to −14.6‰, (ii) for nitrogen gaseous compounds ΔNOx-Norg value between apx. −17 and −5‰, whereas for the ions form ΔNO3 −-Norg value between −9.9 and −3.7‰.

Temporal and spatial atmospheric deposition trends of elements to the boreal forest surrounding bitumen production operations in the Athabasca Oil Sands Region (AOSR), Alberta, Canada were investigated as part of a long-term lichen bioindicator study. The study focused on eight elements (sulfur, nitrogen, aluminum, calcium, iron, nickel, strontium, vanadium) that were previously identified as tracers for the major oil sand production sources. Samples of the in situ epiphytic lichen Hypogymnia physodes were collected in 2002, 2004, 2008, 2011, 2014, and 2017 within a ~150 km radius from the center of surface oil sand production operations in the AOSR. Site-specific time series analysis conducted at eight jack pine upland sites that were repeatedly sampled generally showed significant trends of increasing lichen concentrations for fugitive dust linked elements, particularly at near-field (25 km from a major oil sands production operation) sample locations. Multiple regional scale geostatistical models were developed and evaluated to characterize broad-scale changes in atmospheric deposition based on changes in H. physodes elemental concentrations between 2008 and 2014. Empirical Bayesian kriging and cokriging lichen element concentrations with oil sands mining, bitumen upgrading, coke materials handling, and limestone quarry/crushing influence variables produced spatial interpolation estimates with the lowest validation errors. Gridded zonal mean lichen element concentrations were calculated for the two comprehensive sampling years (2008, 2014) and evaluated for spatial and temporal change. Lichen sulfur concentrations significantly increased in every grid cell within the domain with the largest increases (44-88%) in the central valley in close proximity to the major surface oil sand production operations, while a minor nitrogen concentration decrease (-20%) in a single grid cell was observed. The areal extent of fugitive dust element deposition generally increased with significantly higher deposition to lichens restricted to the outer grids of the enhanced deposition field, reflecting new and expanding surface mining activity.

Epiphytic lichens are well-known indicators of air contamination. The chemical composition of lichens is affected by the concentration of pollutants in the environment. Usually, researchers assess long-term variations in trace elements or other pollutants in the study area or identify the spatial features of air contamination. The aim of this study is to create a database of trace element concentrations in the samples of the epiphytic lichen Hypogymnia physodes growing in the Kaliningrad region. The database can be used as a ‘reference point’ for monitoring studies. Another objective is to identify the spatial patterns of iron, manganese, nickel, cadmium, silver, lead, strontium, rubidium, and calcium in the Kaliningrad region. The samples of wild lichens were collected from pine and birch trees 1.2-1.8 m from the bases of the threes, using a regular grid, in August 2010. One-two-year-old thalli were used in the chemical analysis. The metals Ag, Cd, Cu, Pb, Ni, Fe, Mn, and Zn were determined by AAS (Mn, Fe by flame AAS and the others by ETA-AAS) and the elements Sr, Rb, and Ca by X-ray fluorescence. The concentration of metals in the western coastal area (the Sambian or Kaliningrad Peninsula) is higher than it is in the central and eastern parts of the region. Principal component factor analysis was carried out to detect and characterise different pollution sources and to identify the most polluted areas. The factors of metal emission were described. The authors examined the features of the spatial distribution of trace elements. Prevailing winds are form south-west. Therefore, the highest concentrations of trace elements were found on the Sambian peninsula and on the coasts of the Vistula and Curonian Lagoons. The high concentrations of trace elements in the samples of the lichen H.physodes, which were observed in the coastal part of the region, are associated with human impact and subsequent pollution. The chemical composition of lichens on the Sambian peninsula may have developed under the impact of both local pollution sources – vehicles, thermal energy facilities, and ports – and such factors as transboundary traffic and sea spray.

Lichen substances (i.e. lichen-specific carbon-based secondary compounds) are known to be involved in the uptake and immobilization of metal ions, though the biochemical mechanisms of this interaction are largely unexplained. Previous research on potential effects of lichen substances on heavy metal uptake and tolerance mostly focused on lichens in heavily polluted areas with exceptionally high metal concentrations. In the present study, we aimed at gathering information as to whether lichen substances might be involved in the fine-tuning of metal uptake even at not or low-polluted sites. Therefore, we studied lichen substance concentrations in the epiphytic lichen Hypogymnia physodes and metal concentrations in its substratum in a montane spruce forest of Germany. H. physodes produces two depsides and five depsidones, which had been shown to be involved in metal homeostasis, namely in Cu and Mn uptake, in previous laboratory experiments. The amount of lichen substances increased with increasing heavy metal concentration in the substratum, though the latter varied only in the range of a few μmol g−1 between the sample trees. Variability of lichen substance concentrations in H. physodes within the individual trees was low. Among the different lichen substances of H. physodes, the amount of the depsidone physodalic acid relative to the total of lichen substances was most closely correlated to the concentrations of Cu and Mn in the substratum, whereas the amount of the depsidone 3-hydroxyphysodic acid decreased both with increasing concentrations of these two metals and physodalic acid. Thus, our data suggest that lichen substances contribute to metal homeostasis not only in heavy metal-rich habitats, but also at not or low-polluted sites where the lichen substances apparently help to maintain constant intracellular metal concentrations despite of spatially varying availabilities of metal ions.

The acetone soluble fraction of the methanol extracts of Parmeliaceae lichens: Hypogymnia physodes, Evernia prunastri and Parmelia sulcata, growing on the same host tree (Prunus domestica) and at the same locality was analyzed for the first time by GC and GC-MS. The major identified components were olivetol (33.5 % of the H. physodes extract), atraric acid (30.1 % and 30.3 % of the E. prunastri and P. sulcata extracts, respectively), orcinol (25.0 % of the E. prunastri extract), vitamin E (24.7 % of the P. sulcata extract) and olivetonide (15.7 % of the H. physodes extract). Even though all the identified compounds are known, a number of them were found for the first time in the examined lichens, i.e., orcinol monomethylether (H. physodes), orcinol, atranol, lichesterol, ergosterol (H. physodes and P. sulcata), methyl haematomate, atraric acid, olivetol, vitamin E (H. physodes and P. sulcata) and ?-sitosterol (P. sulcata). This article has been corrected. Link to the correction 10.2298/JSC170614067S

Effect of some pollutants on the lichen Hypogymnia physodes is investigated. It is established experimentally that the greatest changes in the chemical composition of the lichen are caused by short-term exposure to 32 and 65% nitric acid and long-term exposure (14–21 days) to low concentrations (3 and 6%) of sulfuric acid.

We have studied the level of atmospheric pollution in different urban recreational areas using analysis of the chemical composition of the lichen Hypogymnia physodes by Fourier transform IR (FTIR) spectroscopy. We have developed a procedure for determining the dominant pollutant, its concentration, and the degree of its impact on the structure of the lichen.

A sequential extraction procedure was used to study localization of heavy metals in thalli of the lichen Hypogymnia physodes (L.) Nyl. growing under conditions of chronic aerotechnogenic pollution in the Middle Urals. Trends in the seasonal dynamics of metal contents in the thalli were revealed. The dynamics of metal accumulation was also studied in the thalli brought to the polluted zone from the background environment. After one year, the extra-and intercellular contents of most metals in these transplants approached those in the aboriginal thalli and in some cases (intracellular content of cadmium) exceeded them.

Micro-PIXE was applied in the study of arsenic metabolism in the lichen Hypogymnia physodes (L.) Nyl. Lichen thalli were laboratory exposed to a solution of an inorganic arsenic compound arsenate and to a control solution. Perpendicular sections that reveal the morphological properties of the lichen thallus were subjected to microbeam measurements to obtain data on the localization of arsenic and its influence on the distribution and concentrations of the selected macro- and microelements P, S, K, Ca, Cl, Mn, Fe and Zn. Five groups of elements were distinguished regarding losses and redistribution due to arsenic exposure: (1) K and Ca were depleted from all lichen layers; (2) Mn was depleted from the algal layer and lower cortex, (3) Fe was decreased in the algal layer and increased in the lower cortex, (4) Zn was decreased both in the algal layer and the medulla, but increased in the lower cortex, and (5) P and S were decreased in the medulla, but increased in the algal layer and the lower cortex.

This study describes elemental distribution in the epiphytic lichen Hypogymnia physodes (L.) Nyl., with emphasis on heavy metals.Micro-PIXE measurements were performed using the nuclear microprobe at the iThemba LABS, South Africa.Detailed information from different thallus layers was obtained by performing true elemental mapping using the dynamic analysis method, complemented by analyses of selected smaller areas and point analyses.Cl and K concentrations were high near the algal layer whilst S concentrated mostly in the algal and lower cortex layers.The highest concentrations of P were found in the lower cortex.Mn and Zn were mostly concentrated in the algal layer and lower cortex while high concentrations of Fe were noted in the lower cortex.The highest concentrations of Ca and Pb were found in the medullary layer.Mapping of lichen samples soaked in Pb(NO 3)2 solution proved that the highest Pb concentration occurred in the upper and lower cortex. 2002 Published by Elsevier Science B.V.

Optimal defence theory (ODT) attempts to explain variation in plant secondary compounds between different species, different growth conditions and different parts of individual plants. The theory is widely applied to vascular plants and more recently also to seaweeds. Surprisingly, ODT has gained little attention as potential explanation on the distribution of lichen secondary metabolites. In the present study, we analysed intrathalline variation in total phenol content and phenol spectra between reproductive and somatic structures of three foliose lichens, Xanthoria parietina, Vulpicida pinastri and Hypogymnia physodes. The results showed that the concentration of phenolic compounds is higher in sorediate than in non-sorediate lobe ends of V. pinastri and H. physodes as well as in apothecia of X. parietina compared to other parts of the thallus. These results were in accordance with ODT predicting higher allocation of phenols in structures that are most important for the fitness of an individual genet or ramet. This pattern was parallel in all species regardless whether the compounds originate from either acetate-mevalonate or shikimic acid pathways. Moreover, both sexual (X. parietina apothecia) and asexual (soralia of V. pinastri and H. physodes) reproductive structures were higher in phenols compared to somatic tissue.

At 31 sites in Finland the Zn content was determined of the epiphytic lichen Hypogymnia physodes (L.) Nyl. growing on pine and birch, the terricolous lichen Cladina spp. in pine bark, and the inner part of birch bark. The anomalous contents of Zn in H. physodes on pine and Cladina spp. in soil appeared to be strongly related to sulphide ore deposits. Anthropogenic Zn correlated closely with S and Fe in H. physodes on pine and with Fe in Cladina spp. The binding of geogenic Zn was related to iron hydroxides, and was attributed to the different uptake mechanism of S in these lichens. Elevated values of Zn in H. physodes on birch were due to both geogenic and anthropogenic sources. Zinc in pine bark increased with the Zn content in H. physodes and reached a limiting value.

Emissions of mercury from a chlor-alkali plant in central Wisconsin have raised concern about possible effects on biota in the area. Samples of the lichen Hypogymnia physodes, which no longer grows in the area, were transplanted from a site in northeastern Wisconsin and positioned on plastic stands at varying distances up to 1250 m from the plant and sampled for Hg quarterly for one year to test the hypothesis that Hg would be taken up by the lichens and would decline with distance. Average tissue concentrations were elevated when first sampled at three months and continued to increase at the nearest sites until the study ended after one year. Average concentrations after a year of exposure ranged from 4418 ppb at 250 m from the plant to 403 ppb at 1250 m from the plant. The decrease over distance followed a negative exponential pattern. Background concentrations at a control site in northern Wisconsin averaged 155 ppb.

The objective of this study was to examine fluctuations in the production of ethylene by the lichen Hypogymnia physodes indicative of environmental stress caused by air pollutants. In addition, we investigated the accumulation capacity of H. physodes, transplanted in the vicinity of two streets having slow traffic and a highway in the city of Oulu, N. Finland, for a short period (45 d). The amounts of stress ethylene produced by the transplanted lichens was compared with the amounts of airborne elements accumulated in the thallus. H. physodes manifested a high accumulation capacity for Fe and Mg in thalli exposed in either one or both streets with slow traffic in Oulu in comparison with thalli left on the control site in the forest outside of the city. Two of the observed elements, Zn and Fe, exhibited a significant positive correlation with the ethylene concentration detected concomitant with the treatment of lichen thalli with either H2O (pH 6.8) or NaHSO3 (pH 4.0). The concentrations of Pb, Fe, Zn, Mn, and Cu in thalli retrieved from one or both streets with slow traffic (13,600 and 14,290 cars/d) were higher than the concentrations in thalli transplanted in a highway with 25,240 cars/d after 45 d of exposure. Our data thus suggest that the streets with slow traffic and fewer cars are more polluted than the highway.

Three databases on air pollution effects on vegetation were developed by storing bibliographic and abstract data for technical literature on the subject in a free-form database program, ‘askSam’. Approximately 4 000 journal articles have been computerized in three separate database files: BIOLEFF, LICHENS and METALS. BIOLEFF includes over 2 800 articles on the effects of approximately 25 gaseous and particulate pollutants on over 2 000 species of vascular plants. LICHENS includes almost 400 papers on the effects of gaseous and heavy metal pollutants on over 735 species of lichens and mosses. METALS includes over 465 papers on the effects of heavy metals on over 830 species of vascular plants. The combined databases include articles from about 375 different journals spanning 1905 to the present. Picea abies and Phaseolus vulgaris are the most studied vascular plants in BIOLEFF, while Hypogymnia physodes is the most studied lichen species in LICHENS. Ozone and sulfur dioxide are the most studied gaseous pollutants with about two thirds of the records in BIOLEFF. The combined size of the databases is now about 5·5 megabytes.

Hypogymnia physodes was sampled from 179 sites of Scots pine forests regularly distributed throughout Norway. The purpose was to map the nitrogen and sulphur contents of lichen thalli on a large-scale geographical basis, and to relate these values to differences in atmospheric deposition and climate.The lichen nitrogen and sulphur concentrations showed large differences; the highest concentration values being 4-5 times greater than the lowest. The highest nitrogen and sulphur values occurred along the coast of southern Norway and on some sites in the inland of southern Norway. There was a close correlation between the two elements. The lichen N/S ratio decreased with increasing latitude.The nitrogen and sulphur contents ofHypogymnia physodes were both significantly correlated to estimated atmospheric deposition of these two elements in Norway. The degree of explanation improved when climatic variables such as temperature sum, altitude, annual precipitation and temperature were included. Factors promoting growth, such as high bark pH, mild winters, hot summers, high precipitation, high ammonium deposition and high evapotranspiration, were all associated with lower lichen nitrogen and/or sulphur concentrations. Unfavourable growth conditions, such as at high altitude, was related to higher concentrations than expected from deposition models. This indicates that differences in element concentration between nearby localities might be related to local differences in climate and lichen growth conditions. This should be taken into consideration whenever using lichens for biomonitoring.

SUMMARY Three species of lichen: Hypogymnia physodes (L.) Nyl., Pseudevernia furfuracea (L.) Zopf and Usnea filipendula Stirt. with differing sensitivities to SO2 were examined for differences in their ability to carry out sulphite oxidation. The factor responsible for sulphite oxidation is not connected with the metabolic activity of thalli and probably the oxidation does not take place in reaction with O2− The rate of sulphite oxidation may well depend on the content of heavy metals in the thalli.

Lichens have been widely used in biomonitoring studies. In this study, Cd, Cu, Pb and Zn concentrations in some foliose and fruticose lichens which are found in Samsun were investigated and the differences among the species in terms of trace element concentrations and possible interactions among heavy metals were also examined. The results of the present study show that the study area is polluted by Pb and Cd. The cadmium contamination levels were also higher than those of the other elements. The highest Pb (101.39 ppm), Cu (43 ppm) and Zn (67.60 ppm) levels were found in Physcia adscendes. In addition to this, Hypogymnia physodes is one of the foliose species and the best accumulator of Cd (245.73 ppm) as compared to the other species. Likenler biyomonitör çalışmalarında yaygın olarak kullanılırlar. Bu çalışmada, Samsun ilinde yaygın gösteren bazı yapraksı (foliose) ve dalsı (fruticose) likenlerde Cd, Cu, Pb ve Zn konsantrasyonları ve iz element konsantrasyonları açısından türler arasındaki farklılıklar ve ağır metaller arası muhtemel etkileşimler incelendi. Mevcut çalışmanın sonuçları çalışma alanınınn Pb ve Cd tarafından kirlendiğini gösterdi. Kadmiyum kirliliği seviyeleri diğer elemetlerinkinden yüksektir. En yüksek Pb (101.39 ppm), Cu (43 ppm) ve Zn (67.60 ppm) seviyeleri Physcia adscendes'de bulundu. Buna ilave olarak, yapraksı türlerden birisi olan Hypogymnia physodes diğer türler ile karşılaştırıldığında en iyi Cd (245.73 ppm) biriktiren türdür.

The main objective of the present study is to determine the type of environmental contamination in lichens in Gokceada Island in the Northern Aegean Sea in Turkey. We used two different lichen species Cladonia foliacea and Ramalina pollinaria. In the first part of the investigation, the beta activities of lichens have been measured by using a TENNELEC LB 1000-PW detector. The range of beta activity values was between 607 ± 30 and 308 ± 12 Bq/kg for C. foliacea lichens collected from around Tuz Lake and values for R. pollinaria lichens were found to be 740 ± 25 and 541 ± 17 Bq/kg. The second part of the study was concerned with the gamma spectra of the lichen samples measured by using HpGe detector. 137Cs, 134Cs, 40K, 232Th, 226Ra radionuclides were found in C. foliacea collected from around Tepekoy and in R. pollinaria from around Tuz Lake. When these two types of lichens were compared, it was found that R. pollinaria contain more radionuclides. In order to compare and determine which of these lichens act as a better bioaccumulator, K, Mn, Zn, Rb, Sr, Ba and Pb metal content were determined by using Energy Dispersive X-ray fluorescence spectrometry. It was found that C. foliacea collected more Mn and Sr when compared to R. pollinaria.

In laboratory conditions, the ionic equilibriums between a solution and a cation-active layer of epiphytic lichens Hypogymnia physodes immersed in the solution were examined. It was found that such equilibriums, due to exchange of mobile cations: H, Na, K, Ca, and Mg, are established in natural conditions between a lichen and atmospheric water.

A field experiment was carried out in the urban environment of the Grenoble area using two epiphytic lichens: the nitrophytic Physcia adscendens and the acidiphytic Hypogymnia physodes. Two complementary studies characterized this experiment. Firstly, a sampling of the two lichens in 48 sites randomly located throughout the Grenoble area indicated that roads (size and proximity to sampling sites) influenced the nitrogen concentrations of P. adscendens, but not those of H. physodes. Secondly, to study more accurately the influence of roads, a traffic index was calculated and applied along two transects located perpendicularly to urban motorways. Significant positive correlations were found between this traffic index and the total nitrogen concentration of P. adscendens.

This paper describes the use of epiphytic lichens as bioindicators for spatial monitoring of mercury and other elements in air near the natural gas treatment facilities at Molve, Croatia. It is well known that at this location the concentration of mercury in natural gas is very high and therefore it has to be removed from natural gas before further processing in order to prevent technological and environmental problems. In order to monitor the efficiency of an industrial facility for removal of mercury from natural gas, mercury measurements in air and lichens were performed during 9 months in 1997/1998. In situ lichens Parmelia sulcata, Xantoria parientina and Hypogymnia physodes and transplanted lichen species Hypogymnia physodes were used. A good correlation between mercury concentrations in air and lichens was found. The concentrations of barium and bromium were also significantly elevated in transplanted lichens, most probably related to technological process at the gas treatment plant and/or other geological factors. It was confirmed that lichens can successfully be used as bioindicators, provided a careful experiment is designed, particularly the amount of lichens transplanted, the duration of exposure and the initial levels and homogeneity of transplanted lichens.

Mannitol-1-phosphate dehydrogenase [EC 1.1.1.17] activity was demonstrated in extracts of Pseudevernia furfuracea and Hypogymnia physodes. The reaction was found to be highly substrate specific for fructose-6-phosphate/NADH or mannitol-1-phosphate/NAD+. The pH optimum for fructose-6-phosphate reduction was 7.1, and apparent Km values were 1.2 mM for fructose-6-phosphate and 20 μM for NADH. The reaction did not require Mg++ or Ca++. For conversion of mannitol-1-phosphate into mannitol, the occurrence of mannitol-1-phosphatase in Pseudevernia furfuracea is postulated.

A total of 2385 samples of Hypogymnia physodes were collected systematically from sites distributed over the whole country and analysed for Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, N, Na, Ni, Pb, S, Ti and Zn, chiefly for the purpose of tracing areal variations in the deposition of airborne metal elements.

Hypogymnia physodes (L.) Nyl. andDicranoweisia cirrata (Hedw.) Lindb. were transplanted to 12 stations in the vicinity of the steelworks in Frederiksvaerk, Denmark. The transplants were exposed for 7 mo, and samples were taken after 31, 64, 104, 154, 184, and 214 days. Bulk precipitation was collected simultaneously. The concentrations of the metals Cd, Cr, Cu, Fe, Mn, Ni, Ph, V, and Zn were analyzed by atomic absorption spectrophotometry in both transplants and bulk precipitation. The amounts of accumulated metals in the transplants were linearly correlated with fallout from the atmosphere, the bryophytes accumulating the metals slightly faster than the lichens. The metal concentrations in the transplants, as well as the bulk precipitation, followed a decreasing power curve when the distance to the steelworks was increased. It was concluded that transplanted lichens and bryophytes can be applied as monitor organisms of heavy metal pollution from the air.

SUMMARY A simple three-compartment model is used to test the assertion that lichens show low incorporation of assimilate into structural material. Changing specific activities of three fractions equated with the compartments of the model are followed using carbon-14. It is concluded that lichens show tight control over the synthesis of structural material.

Summary Thalli of the lichens Cladonia incrassata and Hypogymnia physodes were incubated with 14 CO 2 At different times after incubation the thalli were prepared for electronmicruscopical autoradiographs by chemical fixation and freeze drying. The 14 CO 2 was assimilated by the phycobionts. After several hours the bulk of radioactivity appeared in the starch of the phycobiont chromatophor. Within a few days 14 C was metabolized into cytoplasmic storage bodies of the phycobionts. Significant labelling in the pyrenoid of the phycobiont chromatophor did not occur until 30 days of culture. A small transfer of 14 C-metabolites to the mycobionts was observed already some hours after incubation. The labelled metabolites seem to pass the plasmalemma and the cell wall without preferring a special area.

A method, including treatment with an enzyme/detergent mixture, of revealing features of the cortical hyphal arrangement in lichen thalli is described. The cortex structure of Parmelia saxatilis, Xanthoria parietina, Hypogymnia physodes and Lecanora muralis is illustrated and described.

In an investigation of Hypogymnia physodes (L.) Nyl. a new depsidone Physodol has been isolated. UV, IR and HrMS studies were used in the investigation. The structure of the component is given in Scheme 1.

Methodological investigations were undertaken to ascertain the appropriate length of exposure in a Scottish industrial town for the transplanted low technology samplers selected for use—spherical moss bags, the lichen Hypogymnia physodes and tak samplers. The appropriate length of exposure for the accumulation of most metals was determined by the following criteria: detectable accumulated concentrations, reliable values (i.e. high replicability) and an exposure time within the limits of practical considerations. Because samplers gave concentrations of most metals which were high and most replicable when exposures were between 8 and 9 weeks, an exposure of 2 months was selected for the main monitoring survey.

Methodological investigations were undertaken to determine the optimal sizes of three types of transplanted low technology sampler—the spherical moss bag, the lichen Hypogymnia physodes and the tak sampler (a synthetic fabric). The optimal sizes were qualified as those providing, for most metals, a combination of high concentrations, reliable values and dimensions which take into account practical considerations. Various sizes of these samplers were exposed for a period of 2 months near a source of atmospheric metal pollution. An analysis of the results allowed optimal sizes of these samplers to be recommended for future surveys: for the spherical moss bags, a dry weight of 0·1 to 0·2 g; for Hypogymnia, a thallus diameter of 0·8 to 1·2 cm and, for the tak samplers, a surface area of 70 cm2.

In order to determine the influence of the hydrogen-ion concentration on the damage exerted to lichens by sulfur dioxide gas, thalli of the species Hypogymnia physodes and Xanthoria parietina were submerged in buffer solutions of pH 2 to pH 8 and subsequently exposed to SO2 gas. Net photosynthesis was employed as a criterion of vitality.

An unusual dip (compared to higher plant behaviour under comparable light conditions) in chlorophyll fluorescence induction (FI) at about 0.2-2 s was observed for thalli of several lichen species having Trebouxia species (the most common symbiotic green algae) as their native photobionts and for Trebouxia species cultured separately in nutrient solution. This dip appears after the usual O(J)IP transient at a wide range of excitation light intensities (100-1800 micromol photons m(-2) s(-1)). Simultaneous measurements of FI and 820-nm transmission kinetics (I(820)) with lichen thalli showed that the decreasing part of the fluorescence dip (0.2-0.4 s) is accompanied by a decrease of I(820), i.e., by a reoxidation of electron carriers at photosystem I (PSI), while the subsequent increasing part (0.4-2 s) of the dip is not paralleled by the change in I(820). These results were compared with that measured with pea leaves-representatives of higher plants. In pea, PSI started to reoxidize after 2-s excitation. The simultaneous measurements performed with thalli treated with methylviologen (MV), an efficient electron acceptor from PSI, revealed that the narrow P peak in FI of Trebouxia-possessing lichens (i.e., the I-P-dip phase) gradually disappeared with prolonged MV treatment. Thus, the P peak behaves in a similar way as in higher plants where it reflects a traffic jam of electrons induced by a transient block at the acceptor side of PSI. The increasing part of the dip in FI remained unaffected by the addition of MV. We have found that the fluorescence dip is insensitive to antimycin A, rotenone (inhibitors of cyclic electron flow around PSI), and propyl gallate (an inhibitor of plastid terminal oxidase). The 2-h treatment with 5 microM nigericin, an ionophore effectively dissipating the pH-gradient across the thylakoid membrane, did not lead to significant changes either in FI nor I(820) kinetics. On the basis of the presented results, we suggest that the decreasing part of the fluorescence dip in FI of Trebouxia-lichens reflects the activation of ferredoxin-NADP(+)-oxidoreductase or Mehler-peroxidase reaction leading to the fast reoxidation of electron carriers in thylakoid membranes. The increasing part of the dip probably reflects a transient reduction of plastoquinone (PQ) pool that is not associated with cyclic electron flow around PSI. Possible causes of this MV-insensitive PQ reduction are discussed.

The epiphytic lichen Hypogymnia physodes was analysed for its content of cadmium, iron and zinc in a suburb of Helsinki. The metal contents were slightly higher than those from unpolluted areas in central Finland. Elevated concentrations were found in the vicinity of a big shipyard.

The background concentrations of lead and cadmium in the epiphytic lichen Hypogymnia physodes were determined and found to depend on altitude. The lead content increases linearly with increasing altitude, whereas the cadmium content increases up to altitudes of 900–1100 m, and then decreases above this height.

Continuous water saturation in Hypogymnia physodes (L.) W. Wats. leads to an increase in the concentration of atranorin. This is taken as an indication that lichen substances are metabolic by-products. Different illumination and SO/sub 2/-fumigation had no significant influence on the content of atranorin. 12 references, 1 figure, 2 tables.