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Two species new to science, Xanthoria pedersenii and X. wennergrenii in the Xanthoria calcicola complex (Xanthoria , Xanthorioideae, Teloschistaceae), characterized by a complex of morphological, anatomical and molecular characters, are described, illustrated and compared with closely related taxa. [ABSTRACT FROM AUTHOR]

In our work we were interested in the toxicity of fluorine on the various parameters of stress: chlorophyll, proteins, and antioxidant system in the lichen Xanthoria parietina (L.) Th. Fr., and for this purpose, lichen thalli were treated by sodium fluoride (NaF) at concentrations of 0, 0.5, 1.0, 5.0 and 10.0 mM, for time scale 0, 24, 48 and 96 h. The analysis results obtained revealed that all the parameters evaluated showed significant variations compared to those of the controls. From the analysis results obtained, it was noted that chlorophyll a (Ca), chlorophyll b (Cb) and total chlorophyll (Ca+b) decreased correlating with exposure times to NaF (r = -0.785, p < 0.001; r = -0.955, p < 0.001; r = -0.899, p < 0.001, respectively), with a significant increase of Ca/b ratio (p = 0.00572**) showing that Cb was more affected than Ca. However, hydrogen peroxide (H2O2) increased (r = 0.949, p < 0.001). In correlation with NaF concentrations, Glutathione (GSH) increased (r = 0.969, p < 0.001), while proteins decreased (r = -0.872, p < 0.001). Furthermore, results showed that catalase activity (CAT) increased correlating with increasing exposure time of X. parietina to increasing concentrations of NaF. Longterm exposure (48 h -96 h) caused a significant decrease in GSH content (p = 0.02*) followed by total destruction at time 96 h. [ABSTRACT FROM AUTHOR]

Lichenicolous fungi associated with Xanthoria calcicola s. lat. are studied in southernmost Scandinavia, i.e., Skåne, the southernmost province in Sweden and southern Denmark. Two species, Didymocyrtis slaptoensis and Pyrenochaeta xanthoriae, are reported as new for the Nordic countries, whereas three species, Didymocyrtis cf. consimilis, Erythricium aurantiacum, and Illosporiopsis christiansenii are recorded for the first time from Skåne. New localities for rare lichenicolous fungi from southern Scandinavia and southernmost Denmark are also listed. Notes on the taxonomy and ecology of Telogalla olivieri and Pyrenochaeta xanthoriae are provided. [ABSTRACT FROM AUTHOR]

This study presents the biopharmaceutical potential and bioactive composition of Xanthoria lichens (X. candelaria, X. elegans, X. parietina) that wildly grown and traditionally utilized as medicine in North Eastern Anatolia, Turkey, which has specific microclimatic and ecological zones. Chromatographic findings revealed significant levels of parietin compound (35 to 49 mg/g extract), low levels of various fatty acids and a volatile compound; a-terpinene in the extracts. The extracts exhibited pronounced antioxidant potential through reducing and scavenging mechanisms; FCR: 33-38 mg gallic acid equivalent, FRAP: 511-815 µ mol Fe2+, ORAC: 1032-1355 µ mol Trolox equivalent per gram extract, respectively and DPPH: IC50: 1.1-2.7, ABTS: IC50: 2-2.3, CUPRAC: IC50: 0.7-1.2, phosphomolybdenum: IC50: 2-2.9, metal chelation: IC50: 1.3-2.3 mg extract/ml, respectively. Concerning enzyme inhibitory activities, the extracts effectively suppressed the activity of acetylcholinesterase (IC50: 0.5-0.75 mg/ml), butyrylcholinesterase (IC50: 0.7-1.1 mg/ml), tyrosinase (IC50: 0.6-0.7 mg/ml), amylase (IC50: 1.7-2 mg/ml), glucosidase (IC50: 0.6-3 mg/ml) and lipase (IC50: 55-79 µg/ml) enzymes. These findings showed that Xanthoria lichens are dominated by parietin as the major key compound and high-tolerated lichen taxa towards to different ecological and climatic conditions. These lichens might be promising sources of novel antioxidant and enzyme inhibitory activities such as Xanthoria candelaria as antioxidant and antilipase, Xanthoria elegans as anticholinesterase, and Xanthoria parietina as antiamylase and antiglucosidase. [ABSTRACT FROM AUTHOR]

La autora describe las especies de Xanthoria y Teloschistes recolectadas en Tucumán (Argentina).

The accumulating ability of the atmospheric Metal Trace Elements (MTE) of two lichenic species thalli; Xanthoria parietina and Ramalina farinacea were evaluated in the region of Megres. The recorded concentrations of MTE (Fe, Cu, Mn, Cd, and Pb) were determined by atomic absorption spectrophotometry (AASF). The ability to accumulate MTE in X. parietina thalli is considerably greater than that of the fruticulous lichen R. farinacea in all stations studied. The general pattern of the elements accumulated in the thalli of the two species in decreasing order of their concentrations was Fe> Mn> Pb> Cu> Cd. The Fe values are very high in X. parietina thalli with an average of 35237.5 ± 3394.2 mg/kg dry wt. In contrast, the Pb concentrations are high, especially in the southern station of the Megres region. The results showed that X. parietina is a hyper-accumulating species of MTE, compared to R. farinacea. This work highlights the ecological importance of this species as a stable and resistant pioneer in this fragile region. [ABSTRACT FROM AUTHOR]

Molecular analyses of the recently described Xanthoria polessica collected from the type locality and of the Australian species X. coomae were used to determine whether these taxa are distinct species or fall within the wide phenotypic variation of the wellknown and cosmopolitan X. parietina. Our results clearly indicate that both taxa should be considered as synonyms of X. parietina since the infraspecific morphological range is accommodated by the observed variation in the thallus and lobe size, their color, position of apothecia, the shape of ascospores, and width of ascospore septum. [ABSTRACT FROM AUTHOR]

Secondary metabolites are the bioactive compounds of plants which are synthesized during primary metabolism, have no role in the development process but are needed for defense and other special purposes. These secondary metabolites, such as flavonoids, terpenes, alkaloids, anthraquinones and carotenoids, are found in Xanthoria genus lichens. These lichens are known as lichenized fungi in the family Teloschistaceae, which grows on rock and produce bioactive compounds. A lot of secondary compounds in plants are induced by UV (100-400 nm) spectra. The present review showcases the present identified bioactive compounds in Xanthoria elegans and Xanthoria parietina lichens, which are stimulated by different amounts of UV-B light (280-320 nm), as well as the biochemistry of the UV-B absorbing compounds. [ABSTRACT FROM AUTHOR]

Eight species, new for science, i.e.: Lobothallia gangwondoana S. Y. Kondr., J.-J. Woo et J.-S. Hur and Phyllopsora dodongensis S. Y. Kondr. et J.-S. Hur from South Korea, Eastern Asia, Ioplaca rinodinoides S. Y. Kondr., K. K. Ingle, D. K. Upreti et S. Nayaka, Letrouitia assamana S. Y. Kondr., G. K. Mishra et D. K. Upreti, and Rusavskia indochinensis S. Y. Kondr., D. K. Upreti et S. Nayaka from India and China, South Asia, Caloplaca orloviana S. Y. Kondr. and Rusavskia drevlyanica S. Y. Kondr. et O. O. Orlov from Ukraine, Eastern Europe, as well as Xanthoria ibizaensis S. Y. Kondr. et A. S. Kondr. from Ibiza Island, Spain, Mediterranean Europe, are described, illustrated and compared with closely related taxa. Fominiella tenerifensis S. Y. Kondr., Kärnefelt, A. Thell et Feuerer is for the first time recorded from Mediterranean Europe, Huriella loekoesiana S. Y. Kondr. et Upreti is provided from Russia for the first time, and H. pohangensis S. Y. Kondr., L. Lőkös et J.-S. Hur for the first time from China, Phoma candelariellae Z. Kocakaya et Halıcı is new to Ukraine, and Staurothele frustulenta Vain. is recorded from the Forest Zone of Ukraine for the first time. Twelve new combinations, i.e.: Bryostigma apotheciorum (for Sphaeria apotheciorum A. Massal.), Bryostigma biatoricola (for Arthonia biatoricola Ihlen et Owe-Larss.), Bryostigma dokdoense (for Arthonia dokdoensis S. Y. Kondr., L. Lőkös, B. G. Lee, J.-J. Woo et J.-S. Hur), Bryostigma epiphyscium (for Arthonia epiphyscia Nyl.), Bryostigma lobariellae (for Arthonia lobariellae Etayo), Bryostigma lapidicola (for Lecidea lapidicola Taylor), Bryostigma molendoi (for Tichothecium molendoi Heufl. ex Arnold), Bryostigma neglectulum (for Arthonia neglectula Nyl.), Bryostigma parietinarium (for Arthonia parietinaria Hafellner et Fleischhacker), Bryostigma peltigerinum (for Arthonia vagans var. peltigerina Almq.), Bryostigma phaeophysciae (for Arthonia phaeophysciae Grube et Matzer), Bryostigma stereocaulinum (for Arthonia nephromiaria var. stereocaulina Ohlert), are proposed based on results of combined phylogenetic analysis based on mtSSU and RPB2 gene sequences. Thirty-one new combinations for members of the genus Polyozosia (i.e.: Polyozosia actophila (for Lecanora actophila Wedd.), Polyozosia agardhiana (for Lecanora agardhiana Ach.), Polyozosia altunica (for Myriolecis altunica R. Mamut et A. Abbas), Polyozosia antiqua (for Lecanora antiqua J. R. Laundon), Polyozosia bandolensis (for Lecanora bandolensis B. de Lesd.), Polyozosia behringii (for Lecanora behringii Nyl.), Polyozosia caesioalutacea (for Lecanora caesioalutacea H. Magn.), Polyozosia carlottiana (for Lecanora carlottiana C. J. Lewis et Śliwa), Polyozosia congesta (for Lecanora congesta Clauzade et Vězda), Polyozosia eurycarpa (for Lecanora eurycarpa Poelt, Leuckert et Cl. Roux), Polyozosia expectans (Lecanora expectans Darb.), Polyozosia flowersiana (Lecanora flowersiana H. Magn.), Polyozosia fugiens (for Lecanora fugiens Nyl.), Polyozosia invadens (for Lecanora invadens H. Magn.), Polyozosia juniperina (for Lecanora juniperina Śliwa), Polyozosia latzelii (for Lecanora latzelii Zahlbr.), Polyozosia liguriensis (for Lecanora liguriensis B. de Lesd.), Polyozosia massei (for Myriolecis massei M. Bertrand et J.-Y. Monnat), Polyozosia mons-nivis (for Lecanora mons-nivis Darb.), Polyozosia oyensis (for Lecanora oyensis M.-P. Bertrand et Cl. Roux), Polyozosia percrenata (for Lecanora percrenata H. Magn.), Polyozosia persimilis (for Lecanora hagenii subsp. persimilis Th. Fr.), Polyozosia poeltiana (for Lecanora poeltiana Clauzade et Cl. Roux), Polyozosia prominens (for Lecanora prominens Clauzade et Vězda), Polyozosia prophetae-eliae (for Lecanora prophetae-eliae Sipman), Polyozosia salina (for Lecanora salina H. Magn.), Polyozosia schofieldii (for Lecanora schofieldii Brodo), Polyozosia sverdrupiana (for Lecanora sverdrupiana Øvstedal), Polyozosia torrida (for Lecanora torrida Vain.), Polyozosia wetmorei (for Lecanora wetmorei Śliwa), Polyozosia zosterae (for Lecanora subfusca? zosterae Ach.)) are proposed. [ABSTRACT FROM AUTHOR]

This paper aims to summarize the main characteristics of lichens that make them excellent bioindicators of air pollution with heavy metals. Also, the paper shows other possible uses of lichen species in the future. [ABSTRACT FROM AUTHOR]

Highlights • Temporal changes in metal concentrations of Xanthoria parietina thalli were examined. • A pronounced upward trend in Pb concentration over time was observed. • Vegetative parts of the thallus and apothecia differ in element accumulation levels. • Definition of part of thallus designated for elemental analysis is highly desirable. • Certain anatomical characteristics are correlated with concentrations of trace metals. Abstract Certain lichens are widely used in air pollution biomonitoring because the contents of various elements in their thalli accurately reflect the chemical composition of the air. Temporal changes in selected concentrations of trace metals in vegetative and generative parts of Xanthoria parietina thalli exposed to urban-related pollution were analysed and the relationship between anatomical organisation and element accumulation identified. The lichen material included thalli relocated to an urban area of Cracow (southern Poland) along with their host trees, which had previously been cultivated at a site characterised by a lower level of air pollution. The thalli were sampled immediately and 1, 3, 6, and 12 months after planting trees. Concentrations of Zn, Pb, Cd, Cu, Ni, and Cr, as measured by means of flame atomic absorption spectrometry (FAAS), and various anatomical characteristics were determined in vegetative thalli and the corresponding apothecia. Accumulation of Pb over time demonstrated a pronounced upward trend; calculated exposed-to-control (EC) ratios indicate 'severe accumulation' of this element. Diverse levels of accumulation in different parts of thalli – higher, in the cases of Pb, Cd, Cu, Ni, Cr, and lower, in the case of Zn, in vegetative parts compared to apothecia – were observed. Thus sampling uniformity is highly desirable in air biomonitoring studies, along with a determination of which part of the thallus is to be designated for elemental analysis. The results also showed that certain anatomical characteristics are correlated with concentrations of metal elements in the thallus. [ABSTRACT FROM AUTHOR]

The protocols commonly applied in surveys with lichens as biomonitors of airborne trace elements require analyses of samples derived from thalli or parts of thalli grown in the last year before sampling, under the postulation that samples of the same size are of the same age. Unfortunately, the influence of ecological site-specific factors on lichen growth is still largely ignored, so that samples of the same size collected in environmentally and climatically diverse sites might actually differ in age. This work aims at quantifying the influence of climatic conditions on the radial growth rates (RaGRs) of Xanthoria parietina, one of the most popular lichen biomonitors. RaGR was monitored in seven populations distributed along an altitudinal transect of 30 km in the Classical Karst (NE Italy), from 20 to 500 m above sea level. For c. 17 months, lobe growth was measured seasonally with a digital calliper, and site-specific climatic variables were monitored by means of thermo-hygrometric sensors and implemented by meteorological data. Finally, the lobe growth of X. parietina was modelled as a function of 18 environmental variables. Results revealed that thalli of relatively dry sites had significantly lower seasonal RaGR with respect to moister ones. Considering that cumulative precipitations were equally distributed along the transect, it was concluded that RaGR of X. parietina is affected negatively by high air temperatures and positively by high relative humidity. The importance of RaGR variation in lichen bioaccumulation studies is critically discussed. [ABSTRACT FROM AUTHOR]

The physiological and ultrastructural effects induced by acute exposure to ozone (O3) were investigated in the lichen Xanthoria parietina. Our working hypothesis was that parietin content and hydration of the thalli may play a role in the modulation of the effects of O3 exposure. Four batches of X. parietina samples, dry and wet, with (P+) and without (P−) parietin, were fumigated for 1 h with 3 ppm O3. The effects of O3 were assessed immediately after the fumigation and after one week of recovery under controlled conditions. O3 fumigation caused physiological and ultrastructural impairment both to the photobiont and the mycobiont, irrespective if samples were fumigated wet or dry, and P+ or P−. However, one week after fumigation, a recovery was observed in P+ samples for the photobiont and in dry samples for the mycobiont. We suggest that the hydration state may play a major role in determining the severity of the damage, while the presence of parietin may promote the recovery. Our results provide physiological and ultrastructural basis to explain the ecological insensitivity of lichens to high environmental levels of ozone occurring during dry Mediterranean summers. [ABSTRACT FROM AUTHOR]

This study investigated the occurrence of toxicity, expressed as damage to the photosynthetic apparatus, in the aquatic fern Azolla filiculoides and the lichen Xanthoria parietina following treatments with diclofenac at different concentrations (0.1, 1, 10 and 100 mg/L) and different exposure times (24, 48, 72 and 240 h). Measurements of photosynthetic efficiency, chlorophyll content and chlorophyll degradation indicated dose- and time-dependent toxicity, since significant differences with control samples as well as among treatments, emerged mainly for the highest concentration (100 mg/L) and the longest time (240 h). In addition, also the mycobiont of the lichen X. parietina showed similar toxic effects, expressed as ergosterol content. The absence of relevant alterations at the lowest concentration (0.1 mg/L) suggested a very limited susceptibility of these species to environmentally relevant levels of this pharmaceutical. [ABSTRACT FROM AUTHOR]

This study is focused on heavy metals accumulation by Xanthoria parietina (L.) Th. Fr., identified on trees as components of shelterbelts. The fieldwork was performed in three counties - Călărași, Vaslui and Dolj - during June-December 2015. A single shelterbelt was investigated in Vaslui and Dolj, while four shelterbelts were investigated in Călărași. Thus, six sampling units were selected within each of the shelterbelts, with an area of 9 m². In the laboratory, the collected lichen thalli were shifted into two thalline components, i.e. the central and peripheral parts of the thalli. The heavy metals accumulation was analysed both in the central and the peripheral parts of the thalli. The results have indicated that heavy metals were accumulated to a higher extent in the central part of thalli than in peripheral parts. The main source of pollution with heavy metals in the studied sites is car traffic. [ABSTRACT FROM AUTHOR]

The mechanisms of nitrogen (N) tolerance in lichens are not yet fully understood. Here, we investigated how the increase of chitin content is related with N excess at inter- and intra-specific levels, by using species with differing ecological N tolerances (the tolerant Xanthoria parietina and Parmotrema hypoleucinum and the sensitive Evernia prunastri and Usnea sp.) and thalli of X. parietina and P. hypoleucinum from sites with different availabilities of N of agricultural origin (livestock), as confirmed by lichen N content and δN. Nitrogen, chitin (N-containing compound), and ergosterol contents were measured in lichen thalli. Nitrogen and chitin contents were higher in tolerant species than those in sensitive ones (inter-specific level) and in thalli collected from the N-polluted site than in thalli from the clean site (intra-specific level). We suggest that chitin contributes to N stress tolerance in lichens, and that excess N can be partially stored as chitin (non-toxic form) in the cell walls of tolerant species. [ABSTRACT FROM AUTHOR]

In this work, accumulation of cosmogenic radionuclide Be in seven species of lichens was determined using HPGe detectors in autumn season. Ramsar city which is located in the north of Iran as one of the high-level natural radiation areas in the world was considered. Lichen species represented good potential in accumulation of Be radionuclide. The foliose species of Xanthoria parietina with the highest activity concentration value of 112.8 ± 1.8 Bq kg was introduced as bioindicator for accumulation of Be radionuclide. Cladonia rangiformis species has got minimum concentration of 64.5 ± 0.8 Bq kg. Also from thallus morphology viewpoint, results showed that Be accumulation in foliose species is higher than in fruticose and crustose lichens species. Also there was relatively large positive correlation between Be and Ra activity concentrations in lichens species. [ABSTRACT FROM AUTHOR]

The paramagnetic properties of lichens were investigated using EPR spectroscopy and Xanthoria parietina (L.) Th. Fr. as a case study. It was found that the concentration of paramagnetic centers in lichen thalli increased as the air-pollution level increased. Possible formation mechanisms of the paramagnetic centers in lichens were discussed. The efficiency of using EPR spectroscopy to study lichens as environmental quality indicators was demonstrated. [ABSTRACT FROM AUTHOR]

The Trebouxia photobiont freshly isolated from Xanthoria parietina (L.) Th. Fr. was used to develop a live cell chondriome (mitochondrial DNA) labelling method. In the initial phase six candidate dyes were tested and compared for mitochondrial labelling utility as assessed by the signal to noise ratio (SNR) of the mitochondrial signal to the adjacent cellular background in standardized confocal images of 30 labelled cells. DIOC7, JC-1 and MitoTracker orange (MTO) dyes showed some labelling ability. MTO had significantly higher utility than the other dyes. In a second phase, MTO concentration was optimized. The final labelling protocol was a 30 minute incubation with 1 μM of MTO. The resultant labelling was suitable for both widefield and confocal microscopy. Both 2D thresholding and 3D volume construction are demonstrated using the resultant data. The protocol can therefore be utilized for both qualitative research and for quantitative measurement of the chondriome in Trebouxia photobionts. This will facilitate a wide range of mitochondrial investigations in lichenology. [ABSTRACT FROM AUTHOR]

Lichen symbioses between fungi and algae represent successful life strategies to colonize the most extreme terrestrial habitats. Consequently, space exposure and simulation experiments have demonstrated lichens' high capacity for survival, and thus, they have become models in astrobiological research with which to discern the limits and limitations of terrestrial life. In a series of ground-based irradiation experiments, the STARLIFE campaign investigated the resistance of astrobiological model organisms to galactic cosmic radiation, which is one of the lethal stressors of extraterrestrial environments. Since previous studies have identified that the alga is the more sensitive lichen symbiont, we chose the isolated photobiont Trebouxia sp. of the astrobiological model Circinaria gyrosa as a subject in the campaign. Therein, γ radiation was used to exemplify the deleterious effects of low linear energy transfer (LET) ionizing radiation at extremely high doses up to 113 kGy in the context of astrobiology. The effects were analyzed by chlorophyll a fluorescence of photosystem II (PSII), cultivation assays, live/dead staining and confocal laser scanning microscopy (CLSM), and Raman laser spectroscopy (RLS). The results demonstrate dose-dependent impairment of photosynthesis, the cessation of cell proliferation, cellular damage, a decrease in metabolic activity, and degradation of photosynthetic pigments. While previous investigations on other extraterrestrial stressors have demonstrated a high potential of resistance, results of this study reveal the limits of photobiont resistance to ionizing radiation and characterize γ radiation-induced damages. This study also supports parallel STARLIFE studies on the lichens Circinaria gyrosa and Xanthoria elegans, both of which harbor a Trebouxia sp. photobiont. Key Words: Astrobiology-Gamma rays-Extremotolerance-Ionizing radiation-Lichens-Photobiont. Astrobiology 17, 154-162. [ABSTRACT FROM AUTHOR]

This study addresses the viability of the lichen Xanthoria elegans after high-dose ionizing irradiation in the frame of the STARLIFE campaign. The first set of experiments was intended to resemble several types of galactic cosmic radiation (GCR) as present beyond the magnetic shield of Earth. In the second set of experiments, γ radiation up to 113 kGy was applied to test the limit of lichen resistance to ionizing radiation. Entire thalli of Xanthoria elegans were irradiated in the anhydrobiotic state. After STARLIFE 1, the metabolic activity of both symbionts was quantified by live/dead staining with confocal laser scanning microscopy. The photosynthetic activity was measured after the respective irradiation to assess the ability of the symbiotic green algae to restore photosynthesis after irradiation. The STARLIFE campaign complements the results of the LIFE experiments at the EXPOSE-E facility on the International Space Station by testing the model organism Xanthoria elegans on its resistance to hazardous radiation that might be accumulated during long-term space exposure. In addition, the photosynthetic activity of metabolically active lichen was investigated after X-ray irradiation up to 100 Gy (3.3 Gy/min). Since previous astrobiological experiments were mostly performed with anhydrobiotic lichen, these experiments will broaden our knowledge on the correlation of physiological state and astrobiological stressors. Key Words: Astrobiology-Extremotolerance-Gamma rays-Ionizing radiation-Lichens-Viability. Astrobiology 17, 136-144. [ABSTRACT FROM AUTHOR]

The photophysical, photoinduced pro-oxidant and antibacterial properties in vitro of the natural occurring parietin (PTN; 1,8-dihydroxy-3-methoxy-6-methyl-9,10-anthraquinone) were evaluated. PTN was extracted from the lichen identified as Teloschistes flavicans (Sw.) Norm. (Telochistaceae). Results indicate that in chloroform solution, PTN presents spectroscopic features corresponding to an excited-state intramolecular proton-transfer (ESIPT) state with partial keto–enol tautomerization. In argon-saturated solutions, the singlet excited state is poorly fluorescent (ΦF = 0.03), decaying by efficient intersystem crossing to an excited triplet state 3PTN*, as detected by laser-flash photolysis experiments. In the presence of triplet molecular oxygen, the 3PTN* was fully quenched producing singlet molecular oxygen (1O2) with a quantum yield of 0.69. In addition, in buffer solutions, PTN has the ability to also generate a superoxide radical anion (O2Ṗ−) in a human leukocyte model and its production was enhanced under UVA-Vis irradiation. Finally, the in vitro antibacterial capability of PTN in the dark and under UVA-Vis illumination was compared in microbial cultures of both Gram positive and negative bacteria. As a result, PTN showed promising photo-induced antibacterial activity through the efficient photosensitized generation of both 1O2 and O2Ṗ− species. Thus, we have demonstrated that PTN, an efficient photo-screening pigment in lichens, is also a good photosensitizer in solution with promising applications in antibacterial photodynamic therapy. [ABSTRACT FROM AUTHOR]

Contamination by atmospheric mercury has been assessed in two different areas from Spain (Las Cuevas, Ciudad Real and Flix, Tarragona) using lichens as biomonitors. The relationship established between mercury contents in the soils and the gaseous mercury (GM) was also observed. It was found that the GM is highest in the vicinity of the source and it is dispersed depending on of the distance to the source and the wind directions. The mercury concentration in the gas phase in Flix was higher than that found in Las Cuevas and also higher than the value that the US EPA recommended. The mercury bioaccumulation in the native lichens from genders Ramalina and Xanthoria were used as biomonitors for absorbing mercury in Las Cuevas and Flix, respectively. The mercury uptake by Ramalina was higher than the amount accumulated by Xanthoria , a difference that was mainly due to the lichen characteristics. The content of mercury in lichens in relation to the mercury in gas was fitted by a Freundlich type equation, indicating that the equilibrium between both phases was established. Besides, transplanted Ramalina lichen in Las Cuevas allowed to obtain the kinetic of mercury uptake. A kinetic model of first order based on the equilibrium was proposed and the mass transfer constants for each sampling station were estimated. As it was expected, these values increased with the predominant wind flow direction. [ABSTRACT FROM AUTHOR]

The new lichenicolous fungus Capronia suijae growing on the thallus of corticolous Xanthoria parietina is described from Belarus and compared with similar species. In addition to its host selection, the species is characterized by comparatively small ascomata, 40–80 μm diam., and (0–1–)3-septate ascospores, 9·5–11·5×4·0–5·0 μm. A key to the lichenicolous fungi growing on Xanthoria s. str. is provided. [ABSTRACT FROM AUTHOR]

This study compared bioaccumulation as well as physiological (content of ergosterol as marker of fungal vitality and photosynthetic efficiency as marker of algal vitality) and ultrastructural effects of glyphosate in the lichen Xanthoria parietina , with the herbicide being provided either by soaking or spraying of the samples. The results showed that bioaccumulation of glyphosate is fast and proportional to the dose supplied, and is independent on the way it is supplied. Toxic effects resulting from glyphosate uptake by both soaking and spraying were evident at physiological and ultrastructural level, both in the algal and fungal partner, with negative effects being generally dose- and time-dependent. Since our results showed that the concentration of glyphosate bioaccumulated in X. parietina remains stable (at least up to 90 days), a perspective is open for using lichens in biomonitoring of atmospheric pollution by glyphosate as a side effect of the application of this herbicide. [ABSTRACT FROM AUTHOR]

Arthonia parietinaria is described as new to science. Host of the type and at the same time the only confirmed host species is the foliose macrolichen Xanthoria parietina . Sequence data of nucLSU rRNA genes reveal a close relationship to Arthonia molendoi . A. parietinaria is recorded for many countries in Europe, western Asia, and northern Africa. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the antimicrobial activity of methanol and chloroform extracts of five lichen species, Melanohalea exasperata, Physcia aipolia, Usnea florida, U. subfloridana and Xanthoria parietina. Antimicrobial activity in culture assays of these foliose and fruticose lichen extracts were examined against two Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli), two Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus), and the yeast Candida albicans using the paper disc method through determination of minimal inhibitory concentrations (MICs). The obtained results indicated the existence of different levels of antibiotic substances in the chloroform and the methanol extracts of the examined lichen species. The chloroform extracts of Usnea subfloridana showed the highest activity against Escherichia coli and Pseudomonas aeruginosa while the methanol extracts of this species were not active against these microorganisms. The chloroform extracts of the examined species exhibited more significant antimicrobial activity than the methanol extracts. None of the species were active against Enterococcus faecalis and Staphylococcus aureus. Most of the lichen extracts indicated a moderate antifungal activity against Candida albicans, except for Physcia aipolia, which was not active. [ABSTRACT FROM AUTHOR]

The isolation of six anthraquinones, erythroglaucin, physcion, xanthorin, emodin, fallacinal and teloschistin, from three species of the lichen genus Xanthoria (X. fallax, X. elegans and X. policarpa) is reported. Physcion is the dominant anthraquinone in all species. the anthraquinones showed broad-spectrum antifingal activity and selective activity against some phytopathogenic bacterial species.

The isolation of six anthraquinones, erythroglaucin, physcion, xanthorin, emodin, fallacinal and teloschistin, from three species of the lichen genus Xanthoria (X. fallax, X. elegáns and A. policarpa) is reported. Physcion is the dominant anthraquinone in all species. The anthraquinones showed broad-spectrum antifungal activity and selective activity against some phytopathogenic bacterial species.

Lichens are sensitive to the presence of ammonia (NH 3 ) in the environment. However, in order to use them as reliable indicators in biomonitoring studies, it is necessary to establish unequivocally the occurrence of certain symptoms following the exposure to NH 3 in the environment. In this paper, we simulated an episode of acute air pollution due to the release of NH 3 . The biological effects of acute air pollution by atmospheric NH 3 have been investigated using N-sensitive ( Flavoparmelia caperata ) and N-tolerant ( Xanthoria parietina ) species. Lichen samples were exposed to ecologically relevant NH 3 concentrations for 8 weeks, simulating three areas of impact: a control area (2 μg/m 3 ), an area of intermediate impact (2–35 μg/m 3 ) and an area of high impact (10–315 μg/m 3 ), with a peak of pollution reached between the fourth and fifth week. Ammonia affected both the photobiont and the mycobiont in F. caperata , while in X. parietina only the photosynthetic performance of the photobiont was altered after exposure to the highest concentration. In the photobiont of F. caperata we recorded chlorophyll degradation as indicated by OD 435/415 ratio, decrease of the photosynthetic performance (as reflected by the maximum quantum yield of primary photochemistry F V / F M and the performance index PI ABS ); in the mycobiont, ergosterol reduction, membrane lipid peroxidation (as reflected by the increase of thiobarbituric acid reactive substances), alteration (decrease) of the secondary metabolite usnic acid. No effects were detected on caperatic acid and dehydrogenase activity. In X. parietina , the only signal determined by NH 3 was the alteration of F V / F M and the performance index PI ABS . The results suggest that physiological parameters in N-sensitive lichens well reflect the effects of NH 3 exposure and can be applied as early indicators in monitoring studies. [ABSTRACT FROM AUTHOR]

This study investigated if treatment of the lichen Xanthoria parietina (L.) Th. Fr. with glyphosate caused uptake of this herbicide as well as physiological alterations. Samples were treated with Glifene SL®, a common commercial glyphosate-based herbicide, at the lowest recommended doses (3.6 g/L) as well as with doses slightly higher than the highest suggested (36 g/L). The results clearly showed glyphosate uptake in X. parietina proportionally to the dose provided. Adverse physiological effects were evident on the photosynthetic apparatus (photosynthetic efficiency, chlorophyll a content, chlorophyll degradation) as well as on the fungal respiration rates and cell membrane integrity (ergosterol content, dehydrogenase activity) already after 24 h from treatment, also at the low application dose. It is concluded that lichens are suitable organisms for monitoring unwanted biological effects from the application of glyphosate-based herbicides, as well as for detecting the accumulation of this compound in the biota, thus screening for its environmental fate. [ABSTRACT FROM AUTHOR]

Secondary metabolites of lichens can be involved in production of chelates with heavy metals. We hypothesized that parietin plays important role in protection of photobiont cells in Xanthoria parietina from an excess of cadmium ions. Two types of X. parietina lichen thalli, natural with presence of secondary metabolite parietin (p+) as well as without parietin (p−) were exposed to different doses of cadmium (up to 300 μmol g −1 dw). Based on determination of the total and intracellular Cd-accumulation, ergosterol and thiobarbituric acid reactive substances (TBARS) content did not show statistically significant differences in the response of both types of thalli (p+ and p−). However, a stronger toxic effect of the highest Cd-dose on photosynthetic pigment content and chlorophyll a fluorescence was observed in the parietin-depleted thalli. The protective role of parietin against Cd excess was better supported and concluded from the differences observed in the production of non-protein thiol compounds (cysteine, glutathione and phytochelatins) involved in Cd detoxification. In the p+ thalli Cys content was stable but GSH content slightly decreased in the studied Cd range, while in the p− thalli these compounds were completely absent at high Cd doses. At Cd doses higher than 37.5 μmol Cd g −1 dw, toxic to both types of X. parietina thalli, Cys and GSH contents were significantly higher in p+ than in p− thalli. Also, the photobiont partner in the p+ thalli was better protected of the metal exposition, and able to produce phytochelatins (PCs) over the whole range of metal, while in the p− thalli the production was completely inhibited at 75 μmol Cd g −1 dw and higher concentrations, together with the inhibition of cysteine (Cys) and reduced glutathione (GSH) production. The obtained results indicate that the parietin layer is a natural barrier decreasing Cd access to algal cells in X. parietina . Comparison of PCs production appeared to be the most sensitive marker for estimation of Cd availability to photobiont in the symbiotic system. [ABSTRACT FROM AUTHOR]

The component composition of mycotoxin complexes is characterized in foliose lichens of genera Nephroma, Peltigera, Umbilicaria, and Xanthoria. The interspecies differences in the genus Peltigera are expressed by the number of metabolites detected, from seven in P. aphthosa to three in P. canina, P. didactyla, P. praetextata, and P. rufescens. In Nephroma arcticum eight mycotoxins occurred regularly, with mycophenolic acid in especially high quantities in comparison with other lichens. In Umbilicaria, of six permanent components the content of alternariol is the highest, and in Xanthoria the content of emodin is the highest. Variation of the quantitative content of mycotoxins in general and of species of lichens is discussed, as is expansion of the background spectrum of these metabolites in collections from different territories. [ABSTRACT FROM AUTHOR]

In this investigation the chemistry of the lichens Gondwania regalis, Teloschistes exilis and Xanthoria candelaria ( Teloschistaceae) have been recorded by means of Raman spectroscopy. The non-destructive analysis provided the recognition of parietin and conjugated polyenes, probably belonging to the carotenoid family for all the investigated specimens. Bands at ca. 1370 and 1600 cm−1, respectively, assigned to the ν(C-O) and ν(CO) modes of the phenyl group of the anthraquinone compound, as well the bands at ca. 1005, 1158 and 1527 cm−1, possibly assigned to the β-carotene in the FT-Raman spectra, have provided valuable spectroscopy data for the identification of the biomarkers for these lichen pigments. Thus, this is the first report of parietin and carotenoid in T. exilis and X. candelaria tissues even as the parietin anthraquinone for G. regalis tissues, which are effective pigments against free radicals from UV radiation. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper we investigated whether a different accuracy in sample cleaning prior to the analysis may affect the elemental composition of unwashed samples of the lichen Xanthoria parietina. To this purpose, samples of this lichen were collected from a remote area of Sardinia (Italy) and randomly divided into two aliquots, one cleaned very carefully (ca. 3-4 h to obtain ca. 200 mg of material for analysis) and the other cleaned with a lower efficiency (ca. 1-2 h). Samples were analysed by ICP-MS for the content of Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, V and Zn. The results indicated that an accurate cleaning is effective for reducing the content of Al and Fe, i.e. soil-related elements, but that it has no effect on the concentrations of other elements less represented in the soil. [ABSTRACT FROM AUTHOR]

Environmental cerium (Ce) levels are likely to increase in the near future and monitoring of its biological effects will therefore be necessary. The aim of this study was to test if treatment of the lichen Xanthoria parietina with Ce-containing solutions (0.1mM, 1mM, 10mM and 100mM) causes Ce bioaccumulation (both extra- and intra-cellularly) as well as physiological (sample viability, membrane lipids peroxidation, photosynthetic performance, water-soluble proteins content) and ultrastructural alterations. The results showed that treatment with Ce solutions induces Ce bioaccumulation, both extra-cellularly and intra-cellularly, which in turn causes an acute toxicity, evident as decreased sample viability, marked decrease in the photosynthetic performance and important changes in the ultrastructure. [Copyright &y& Elsevier]

In this study, we investigated whether ammonia emissions from industrial composting of organic waste may influence the surrounding environment, using lichens as bioindicators. To this purpose, samples of N-tolerant and N-sensitive lichens, namely Xanthoria parietina and Evernia prunastri, were transplanted for 1-3 months along transects at increasing distance (0-400 m) from a composting facility in Tuscany, Italy. Atmospheric concentrations of ammonia were measured using passive samplers. The physiological response of lichen transplants was investigated by means of the photosynthetic efficiency (measured as chlorophyll a fluorescence emission), the integrity of cell membranes (measured as electrolyte leakage), and sample viability (measured as enzymatic activity of dehydrogenase). Epiphytic lichen communities were investigated using biodiversity indices. The results showed decreasing concentrations of ammonia, from 48.7 μg/m at the composting facility to 2.7 μg/m at 400 m. The N-tolerant X. parietina was not affected and some physiological parameters even showed a higher performance, while the N-sensitive E. prunastri showed a reduced performance with increasing atmospheric concentrations approaching the source. A shift from lichen communities composed by meso-acidophilous species (actual condition) to more nitrophilous communities in the near future, approaching the composting facility is suggested. It is concluded that lichens can provide useful data for decision-makers to establish correct science-based environmentally sustainable waste management policies. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) empirical critical levels for Europe were re-evaluated in 2009, based mainly on the ecological responses of lichen communities without acknowledging the physiological differences between oligotrophic and nitrophytic species. Here, we compare a nitrogen sensitive lichen (Evernia prunastri) with a nitrogen tolerant one (Xanthoria parietina), focussing on their physiological response (Fv/Fm) to short-term NH3 exposure and their frequency of occurrence along an NH3 field gradient. Both frequency and Fv/Fm of E. prunastri decreased abruptly above 3 μg m−3 NH3 suggesting direct adverse effects of NH3 on its photosynthetic performance. By contrast, X. parietina increased its frequency with NH3, despite showing decreased capacity of photosystem II above 50 μg m−3 NH3, suggesting that the ecological success of X. parietina at ammonia-rich sites might be related to indirect effects of increased nitrogen (NH3) availability. These results highlight the need to establish NH3 critical levels based on oligotrophic lichen species. [Copyright &y& Elsevier]

The green algal photobionts of 12 Xanthoria, seven Xanthomendoza, two Teloschistes species and Josefpoeltia parva (all Teloschistaceae) were analyzed. Xanthoria parietina was sampled on four continents. More than 300 photobiont isolates were brought into sterile culture. The nuclear ribosomal internal transcribed spacer region (nrITS; 101 sequences) and the large subunit of the RuBiSco gene (rbcL; 54 sequences) of either whole lichen DNA or photobiont isolates were phylogenetically analyzed. ITS and rbcL phylogenies were congruent, although some subclades had low bootstrap support. Trebouxia arboricola,T. decolorans and closely related, unnamed Trebouxia species, all belonging to clade A, were found as photobionts of Xanthoria species. Xanthomendoza species associated with either T. decolorans (clade A), T. impressa, T. gelatinosa (clade I) or with an unnamed Trebouxia species. Trebouxia gelatinosa genotypes (clade I) were the photobionts of Teloschistes chrysophthalmus,T. hosseusianus and Josefpoeltia parva. Only weak correlations between distribution patterns of algal genotypes and environmental conditions or geographical location were observed. [ABSTRACT FROM PUBLISHER]

Highlights: [•] Effects of external Spd on the lichen Xanthoria parietina under Al stress were investigated. [•] Increased GR activity and psbA mRNA transcript levels were observed in the X. parietina thalli. [•] Application of Spd could mitigate aluminium-induced oxidative damage on lichen X. parietina. [Copyright &y& Elsevier]

We studied group I introns in sterile cultures of selected groups of lichen photobionts, focusing on Trebouxia species associated with Xanthoria s. lat. (including Xanthomendoza spp.; lichen-forming ascomycetes). Group I introns were found inserted after position 798 ( Escherichia coli numbering) in the large subunit ( LSU) r RNA in representatives of the green algal genera Trebouxia and Asterochloris. The 798 intron was found in about 25% of Xanthoria photobionts including several reference strains obtained from algal culture collections. An alignment of LSU-encoded r DNA intron sequences revealed high similarity of these sequences allowing their phylogenetic analysis. The 798 group I intron phylogeny was largely congruent with a phylogeny of the internal transcribed spacer region, indicating that the insertion of the intron most likely occurred in the common ancestor of the genera Trebouxia and Asterochloris. The intron was vertically inherited in some taxa, but lost in others. The high-sequence similarity of this intron to one found in Chlorella angustoellipsoidea suggests that the 798 intron was either present in the common ancestor of Trebouxiophyceae, or that its present distribution results from more recent horizontal transfers, followed by vertical inheritance and loss. Analysis of another group I intron shared by these photobionts at small subunit position 1512 supports the hypothesis of repeated lateral transfers of this intron among some taxa, but loss among others. Our data confirm that the history of group I introns is characterized by repeated horizontal transfers, and suggests that some of these introns have ancient origins within Chlorophyta. [ABSTRACT FROM AUTHOR]

To investigate the mechanisms of nitrogen (N) tolerance in lichens, we examined the physiological responses to increased N availability in different functional groups. Thalli of the nitrophytic Xanthoria parietina (L.) Th.Fr. previously grown both in an N-poor environment (~2kgNha[sup -1] year[sup -1]) and in an N-rich environment (~52 kg Nha[sup -1] year[sup -1]) were compared with the oligotrophic species Evernia prunastri (L.) Ach. and Usnea sp. Lichens were submitted to ammonium treatments. Maximum PSII efficiency, redistribution of the ions between the intra- and extracellular compartments and potassium and magnesium concentrations were the parameters used to check for the effects of N supply. The buffering capacity of the lichen extracts was also determined in untreated lichen thalli to check if different lichen behaviours were due to their ability to maintain the pH. The results showed a more similar response between X. parietina from the N-poor environment and the N-sensitive species than between X. parietina from the N-poor and N-rich environments, suggesting that X. parietina achieved N-tolerance after long-term exposure to N-rich environment. These results are important in understanding the effects of chronic ammonium pollution on one of the most sensitive components of the ecosystem, linking physiological response and ecological consequences. [ABSTRACT FROM AUTHOR]

Abstract: Airborne metal deposition in the major urban and the industrial districts of Kocaeli was monitored using Xanthoria parietina lichen specimen as a biomonitoring organism. Lichen samples were analyzed for Al, As, Co, Cd, Cu, Fe, Hg, Mn, Ni, Pb, Ti, Tl, V and Zn contents to determine the relationship between the potential pollutant sources in the region and the degree of airborne metal deposition. Results showed that airborne metal deposition in the Kocaeli province was widespread and environmental alteration was serious near the industrial facilities. Mean metal concentrations of lichen samples in the industrial district (Dilovası) of Kocaeli were two to seven folds higher than those in the urban districts of Kocaeli: Mn (7), Pb–Cd–Zn (6), Fe–Ni–Cu (3) and Al–Co–Ti–Hg–As–V (2). Environmental alteration in Dilovası region was severe in terms of all metals analyzed. Cluster analysis showed that metal industry (iron–steel, aluminum, zinc) in Dilovası, fossil fuel combustion processes related to the industry and power plant and heavy traffic contributed significantly to the metal emission in Dilovası region. Airborne metal deposition in the urban districts of Kocaeli was high especially around the coal-fired cement plant in Hereke and petroleum refinery in Körfez. Fossil fuel combustion and traffic emission were among the important sources of airborne metals in the urban–suburban districts. [Copyright &y& Elsevier]

Abstract: Atmospheric mercury (Hg) deposition around a mercury cell chlor-alkali plant located near Grenoble, south-east France, was assessed using Hg concentrations in lichens and soils. Hg content in the epiphytic Xanthoria parietina lichen ranged from ∼0.07 to ∼2.51μgg−1, and concentrations decreased with increasing distance to the plant, with a contamination radius of ∼2km. Soil Hg concentration profiles were consistent with an atmospheric origin, with higher concentrations in the upper part of the profiles. Concentration of Hg in lichens and top soils (0–10cm depth) as a function of the distance to the chlor-alkali plant exhibited highly similar variations. Using a simple first-order deposition model, mean Hg fallouts for the whole history of chlor-alkali plant are estimated to ∼36gHgday−1 in this area, compatible with values reported for reactive gaseous mercury (RGM) emissions of similar industrial plants. Using literature data on RGM to total Hg emission ratio, we estimate that the plant emitted ∼650kgHgyear−1. Two kilometres away from the plant, Hg content in top soils falls to values of (0.13±0.07)μgg−1 Hg, which is the local anthropogenic geochemical background level, but higher than unperturbed geochemical background found at the bottom of soil profiles (below 40cm depth) estimated to (0.04±0.01)μgg−1 Hg. The present study evidences that lichens are a pertinent proxy for soil Hg contamination around chlor-alkali plants. They are attractive biomonitoring tools since sampling and preparations protocols for lichens are less time consuming than those used for soils. [Copyright &y& Elsevier]

Abstract: The sensitivity of three foliose lichen species to urban environments with different air pollution loads and climatic conditions was tested using chlorophyll a fluorescence (Chl a F) PAM measurements. Transplants of Xanthoria parietina (L.) Th. Fr., Flavoparmelia caperata (L.) Hale and Parmotrema perlatum (Huds.) M. Choisy collected in a pristine site of the Classic Karst (Trieste, NE Italy) were exposed for 12 weeks (August–December 2008) at that site (control, A), and in two urban sites with heavy traffic in Trieste (B) and Udine (C). Concentrations of the main gaseous pollutants were monitored by passive samplers in A (NO2, O3), and by pollution monitoring stations in B and C (NOX, NO2, SO2, O3). In the laboratory, Kautsky curves were induced under standardized conditions at species-specific PPFD values before exposure, after 6 weeks and at the end of the exposure. Significant decrease in F v/F m was only observed in P. perlatum transplants exposed in B, possibly as a consequence of the dry conditions of that site. Non-photochemical quenching (NPQ) was negatively affected in all three species, although with different intensity, in both urban sites, but more intensively in C than in B. Chl a F data shows clearly that (i) the decrease of NPQ was modulated by time exposure to NOX as well as by NOX concentration, and (ii) the species response to pollutants was related to species ecology: X. parietina, which is more nitro- and xerophytic than the other two species, tolerated better the transplant environmental conditions, confirming recent floristic observations carried out in several urban areas of Central Europe. [Copyright &y& Elsevier]

In this study, epiphytic lichen Xanthoria parietina was applied as the biomonitor of air pollution to determine the environmental influence in the vicinity of Soma coal-fired power plant. Thalli of lichen Xanthoria parietina growing on olive, oak and poplar trees were collected with their substrate in 2004–2006. They were taken from 44 different stations located in 3×3 km grids within an area of 30 km in diameter around the Soma power plant near the town of Soma. Lichen samples were analyzed by using the ICP-MS for As, Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb, Se, Th, U, V and Zn elements and their concentrations were mapped. The sample analyses results were evaluated by using the statistical software (SPSS 11). Average element contents of samples were, in descending order, Fe > Zn > V > Pb > Cr > Cu > Ni > As > Co > U > Th > Se > Cd > Hg. Results obtained in the current study were generally found to be higher than the data reported in literature although some lower values exist for Cd, Co, Hg, Ni, Pb elements. The most polluted areas were found to be those in the vicinity of the coal-fired power plant, particularly along the direction of predominant wind and in the corridor which runs from west to southeast direction due to topographic conditions. We believe that this research which is conducted around a coal-fired power plant will shed light on future research on pollution. [ABSTRACT FROM PUBLISHER]

Lichens are compound entities of a fungal partner ('mycobiont') and one or more photosynthetically active algae or cyanobacteria ('photobionts'). The organisms live in an intimate, symbiotic association which has been classified as a mutualistic or controlled parasitic relationship. Several metabolites from lichens display unique structures with unknown functions, and only a few model species have been analysed comprehensively. The complex metabolic interplay between the organisms in lichens is also incompletely understood. Earlier experiments with C-labelled precursors indicated that the photobionts produce from CO glucose or sugar alcohols (e.g. ribitol and arabitol) which are then transferred to the mycobionts. In the fungi, these compounds are believed to be converted into mannitol serving as the carbon and energy source in the downstream metabolic processes. Recent methodological developments in spectroscopy and 'systems biology' now enable a concise analysis of the metabolite profiles, networks and fluxes by non-targeted quantitative approaches. In this review, we summarize the current knowledge about lichen metabolism and report on the potential of the advanced methods to reinvestigate lichen chemistry and metabolism on a quantitative basis. [ABSTRACT FROM AUTHOR]