Lichen Xanthoria Parietina Research Articles

Biomonitoring of atmospheric heavy metals in native lichen Xanthoria parietina around Salda Lake (Burdur – Turkey), a special environmental protection area

Biomonitoring of atmospheric heavy metals in native lichen Xanthoria parietina around Salda Lake (Burdur – Turkey), a special environmental protection area

Integration of ecological indicators to assess a multitemporal impact of cement industries

The present study evaluated an integrated biomonitoring approach based on three different bioindicators: tree rings, lichens, and beetles in a complex environment (urban-industrial-forest). In Central Italy, four sampling sites were selected to assess the anthropogenic impact of cement plants taking into account (1) long-term exposure (1988–2020) through the analysis of trace elements in tree rings of Quercus pubescens; (2) medium-term exposure (2020–2021) through the analysis of trace elements in thalli (outermost portions) of the lichen Xanthoria parietina; (3) short-term exposure in spring 2021 through the bioaccumulation and evaluation of sample vitality in transplants of the lichen Evernia prunastri and a periodic survey of entomological biodiversity carried out during spring and summer 2021. Trace elements of industrial origin were found in tree rings, with different levels of accumulation between 1988 and 2020 and a maximum in 2012. Native thalli of the lichen X. parietina showed an overall low bioaccumulation of trace elements except for Cr, probably reflecting the influence of national lockdown measures. The transplants of E. prunastri showed a weak stress response in the industrial and urban sites, but not in the forest, and identified Tl and V as the main elements contributing to atmospheric contamination, with peaks at the industrial sites. Concerning the beetles, a significantly lower number of species was found at the Semonte industrial site.

The Roles of the Anthraquinone Parietin in the Tolerance to Desiccation of the Lichen Xanthoria parietina: Physiology and Anatomy of the Pale and Bright-Orange Thalli.

Lichens are symbiotic organisms that effectively survive in harsh environments, including arid regions. Maintaining viability with an almost complete loss of water and the rapid restoration of metabolism during rehydration distinguishes lichens from most eukaryotic organisms. The lichen Xanthoria parietina is known to have high stress tolerance, possessing diverse defense mechanisms, including the presence of the bright-orange pigment parietin. While several studies have demonstrated the photoprotective and antioxidant properties of this anthraquinone, the role of parietin in the tolerance of lichens to desiccation is not clear yet. Thalli, which are exposed to solar radiation and become bright orange, may require enhanced desiccation tolerance. Here, we showed differences in the anatomy of naturally pale and bright-orange thalli of X. parietina and visualized parietin crystals on the surface of the upper cortex. Parietin was extracted from bright-orange thalli by acetone rinsing and quantified using HPLC. Although acetone rinsing did not affect PSII activity, thalli without parietin had higher levels of lipid peroxidation and a lower membrane stability index in response to desiccation. Furthermore, highly pigmented thalli possess thicker cell walls and, according to thermogravimetric analysis, higher water-holding capacities than pale thalli. Thus, parietin may play a role in desiccation tolerance by stabilizing mycobiont membranes, providing an antioxidative defense, and changing the morphology of the upper cortex of X. parietina.

Elemental profile identifies metallurgical pollution in epiphytic lichen Xanthoria parietina and (hypo)xanthine correlates with metals

The accumulation of 55 elements in lichens under the heap of a former nickel smelter (village Dolná Streda, Slovakia) and at eight sites at different distances from the heap plus six sites throughout Slovakia was studied to determine the elemental profile. The major metals in the heap sludge and in the lichens below the heap (Ni, Cr, Fe, Mn, and Co) were surprisingly low in lichens from both the near and far vicinity of the heap (4–25 km), indicating limited airborne spread. However, two different sites with metallurgical activity (another site near the ferroalloy producer in Orava) typically contained the highest amount of individual elements, including rare earth elements, Th, U, Ag, Pd, Bi and Be, and their separation from other sites was confirmed by PCA and HCA analyses. In addition, the amounts of Cd, Ba and Re were highest at sites without a clear source of pollution and further monitoring is needed. It was also an unexpected finding that the enrichment factor calculated using UCC values was increased (often considerably >10) for 12 elements at all 15 sites, indicating eventual anthropogenic contamination with P, Zn, B, As, Sb, Cd, Ag, Bi, Pd, Pt, Te and Re (and other EF values were locally increased). Metabolic analyses showed a negative correlation between some metals and metabolites (ascorbic acid, thiols, phenols and allantoin), but slightly positive (amino acids) or highly positive correlation with purine derivatives hypoxanthine and xanthine. The data suggest that lichens adapt their metabolism to excessive metal loading and that epiphytic lichens are suitable for identifying metal contamination even at apparently clean sites.

Oxidative stress caused by lead in the lichen Xanthoria parietina

The assessment of the air quality is a major concern to the current time. The monitoring and maintenance of air quality necessarily pass by detecting and estimating the overall air pollution. The use of lichens must be an assessmenttool to be studied. In our work we were interested about the toxicity of lead on the various parameters of stress in the lichen Xanthoria parietina. For this purpose, lichen thalli have been incubated at lead concentrations of 0, 0.5, 1.0, 5.0 and 10.0 mM, for time scale of 0, 24, 48 and 96 hours. The obtained results showed that lead has an action on the various studied parameters, and the intensity of oxidative stress observed in lichens thalli depends on the concentration, and time of exposure. Lead induced a decrease in chlorophyll and protein contents, and an increase in the contents of catalase, hydrogen peroxide and reduced glutathione. Furthermore, the results also showed that high concentrations of lead caused total destruction of reduced glutathione.

Oxidative stress induced by fluorine in Xanthoria parietina (L.) Th. Fr.

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. Long-term exposure (48 h -96 h) caused a significant decrease in GSH content (p = 0.02*) followed by total destruction at time 96 h.

Survivability of the lichen Xanthoria parietina in simulated Martian environmental conditions

Xanthoria parietina (L.) Th. Fr. is a widely spread foliose lichen showing high tolerance against UV-radiation thanks to parietin, a secondary lichen substance. We exposed samples of X. parietina under simulated Martian conditions for 30 days to explore its survivability. The lichen’s vitality was monitored via chlorophyll a fluorescence that gives an indication for active light reaction of photosynthesis, performing in situ and after-treatment analyses. Raman spectroscopy and TEM were used to evaluate carotenoid preservation and possible variations in the photobiont’s ultrastructure respectively. Significant differences in the photo-efficiency between UV irradiated samples and dark-kept samples were observed. Fluorescence values correlated with temperature and humidity day-night cycles. The photo-efficiency recovery showed that UV irradiation caused significant effects on the photosynthetic light reaction. Raman spectroscopy showed that the carotenoid signal from UV exposed samples decreased significantly after the exposure. TEM observations confirmed that UV exposed samples were the most affected by the treatment, showing chloroplastidial disorganization in photobionts’ cells. Overall, X. parietina was able to survive the simulated Mars conditions, and for this reason it may be considered as a candidate for space long-term space exposure and evaluations of the parietin photodegradability.

Interaction effect of fungicide and chitosan on non-target lichenized fungi

Excessive use of plant growth stimulants and pesticides is currently a considerable problem, especially in agriculture, horticulture, and arboriculture. Understanding the impacts of these compounds and their combinations on non-target organisms is crucial to minimize unintended consequences, while maintaining their use in plant protection. The aim of this study was to test how long-term spraying with different solutions of natural biostimulator chitosan, synthetic fungicide Switch 62.5 WG, and their combinations affects the physiology of epiphytic lichen Xanthoria parietina naturally occurring in fruit orchards and farmlands. We showed that fungicides composed of fludioxionil and cypronidil, as well as the combined use of such fungicides together with chitosan, can cause the considerable impairment of lichen physiology, and these disturbances relate to both algal and fungal partners of the symbiotic association. This negative effect was especially visible in the loss of cell membrane integrity, the high level of membrane lipid peroxidation, and changes in chlorophyll fluorescence parameters on the last day of the experiment. The combined use of these agents also leads to clear disturbances in the functioning of the mitochondrial respiratory chain, which was manifested by increased NADH dehydrogenase activity, while the use of these compounds separately led to a decrease in the activity of this enzyme. We concluded that the regular use of these agents in fruit tree cultivation may cause serious ecological consequences for epiphytic lichen communities as a result of the death of lichen thalli. This study suggests that the impact of some plant protection agents, both individually and in combinations, merits further attention in terms of their impact on non-target fungi.

Synthesis and Antioxidant Evaluation of O-Methylated Emodacidamides: Starting from Parietin, a Secondary Metabolite of Lichen Xanthoria parietina.

Polyhydroxy-anthraquinones bearing amino acids are found rather seldom in nature. Emodacidamides, isolated from a marine-derived fungus, Penicillium sp. SCSIO sof101 by Luo et al. (2017) are the first natural example of amino acid conjugated anthraquinone. In this study, O-methylated emodacidamides and emodinic acid-anilides were synthesized starting from parietin, extracted from the lichen Xanthoria parietina (L.) Th. Fr. The structural elucidations of prepared compounds were confirmed by 1D and 2D NMR analyses including HSQC and HMBC techniques. In addition, all newly synthesized compounds were evaluated for the antioxidant activities with free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging. The synthesized compounds showed low to moderate antioxidant and DPPH scavenging activities. The antioxidant activities were supported within quantum chemical calculations using the DFT-B3LYP/6-311++G(d,p) level of theory. It is observed that the antioxidant activity of emodacidamides mostly depends on the phenolic groups on anthraquinone ring. The phenolic groups on other substituents help to improve antioxidant activity and also the position of hydroxy group is a decisive factor for antioxidant ability.

Enhanced culturing techniques for the mycobiont isolated from the lichen Xanthoria parietina

Lichens and their isolated symbionts are potentially valuable resources for biotechnological approaches. Especially mycobiont cultures that produce secondary lichen products are receiving increasing attention, but lichen mycobionts are notoriously slow-growing organisms. Sufficient biomass production often represents a limiting factor for scientific and biotechnological investigations, requiring improvement of existing culturing techniques as well as methods for non-invasive assessment of growth. Here, the effects of pH and the supplement of growth media with either D-glucose or three different sugar alcohols that commonly occur in lichens, D-arabitol, D-mannitol and ribitol, on the growth of the axenically cultured mycobiont isolated from the lichen Xanthoria parietina were tested. Either D-glucose or different sugar alcohols were offered to the fungus at different concentrations, and cumulative growth and growth rates were assessed using two-dimensional image analysis over a period of 8 weeks. The mycobiont grew at a pH range from 4.0 to 7.0, whereas no growth was observed at higher pH values. Varying the carbon source in Lilly-Barnett medium (LBM) by replacing 1% D-glucose used in the originally described LBM by either 1%, 2% or 3% of D-mannitol, or 3% of D-glucose increased fungal biomass production by up to 26%, with an exponential growth phase between 2 and 6 weeks after inoculation. In summary, we present protocols for enhanced culture conditions and non-invasive assessment of growth of axenically cultured lichen mycobionts using image analysis, which may be useful for scientific and biotechnological approaches requiring cultured lichen mycobionts.

Effects of wood distillate (pyroligneous acid) on sensitive bioindicators (lichen and moss)

Wood distillate (pyroligneous acid) can be successfully applied in agriculture to increase crop quality and productivity with a lower risk for the environment respect to synthetic chemical herbicides, pesticides or fertilizers. However, the effects of wood distillate on the environment and biota are still under investigation, depending on biological attributes of potentially influenced organisms. The potential toxicological effects of wood distillate on sensitive non-target organisms, lichens and mosses, are studied for the first time. The physiological parameters (chlorophyll a fluorescence emission FV/FM and PI(ABS), chlorophyll content, spectral reflectance, antioxidant power, and dehydrogenase activity) and eventual bioaccumulation of selected elements (As, Ba, Cd, Cr, Cu, Fe, Ni, Pb, Zn) were investigated in the lichen Xanthoria parietina and the moss Hypnum cupressiforme after short-term treatments over a range of wood distillate solutions (1:300, 1:500, 1:700) to detect potential early stress responses. Overall, the lichen did not show changes after the treatments, while in the moss wood distillate caused only modest alterations in FV/FM and PI(ABS) and progressive increasing of antioxidant activity according to the dose supplied. The bioaccumulation of toxic elements was low and did not show any pattern of uptake with increasing concentrations of wood distillate.

Air quality assessment in different environmental scenarios by the determination of typical heavy metals and Persistent Organic Pollutants in native lichen Xanthoria parietina

The study was aimed to evaluate the ability of native lichen Xanthoria (X.) parietina to biomonitor and bioaccumulate some heavy metals (As, Cd, Co, Cr, Ni, Pb), PAHs, PCDDs, PCDFs, PCBs and PBDEs and to evaluate the use of the native X. parietina as a multi-tracer tool for scenarios characterized by different anthropogenic pressures. Samples of native X. parietina were collected in six different sites (two green, two residential and two industrial areas, respectively) and analyzed for the target compounds.The results show that X. parietina was a useful tool for the biomonitoring of air quality in the selected areas, and was able to bioaccumulate all the studied metals and POPs. In particular, the total concentrations dry weight (dw) ranged between 8.1 and 103.4 mg kg−1 for metals, from 113 × 103 to 183 × 103 ng kg−1 for PAHs, from 868 to 7685 ng kg−1 for PCBs, from 14.3 to 113.8 ng kg−1 for PCDDs/Fs (∑TEq = 0.9–7.1), and from 194 to 554 ng kg−1 for PBDEs.Besides, in general, the levels of analytes recovered in the different samples of lichen show an increasing trend from green to industrial sites, especially for PCBs (mean values equal to 1218, 4253 and 7192 ng kg−1 respectively for green, residential and industrial areas).The statistical approach, based on Pearson's correlation and principal component analysis tests, showed that one of the industrial sites was well-separated from the others, that resulted grouped due to some similarities.

Efficiency of Lichenicolous Fungi in Controlling Citrus Lichen Xanthoria parietina

Lichenicolous fungi are not the same as the fungi that is the component of the lichen, which are known as lichenized fungi. This study was carried out to investigate the parasitic fungi which colonizing and attacking thalli and apothecia of citrus lichen Xanthoria parietina and the efficiency of using these fungias lichenicolouss in its control. Several fungi were isolated from decayed thalli and apothecia and identified as Xanthoriicola physciae, Cladosporium sp., Alternaria sp., Drechslera sp., Botryodiplodia sp., Mucor sp., Aspergillus sp., Pestalotiopsis sp., Epicoccum nigrum, Fusarium sp. , and Tellogalla oliveri. Xanthoriicola physciae was the most frequent and aggressive fungus in all collected decayed samples, anatomical investigation of decayed thalli and apothecia caused by Xanthoriicola physciae showed destruction and lytic symptoms on the tissue and formation of black mass production of hypha and conidiospores in the infected thalli and apothecia. All lichenicolous fungi were isolated and cultivated on PDA and Malt yeast extract media, parasitism of lichenicolous fungi was done by spore suspension of lichenicolous fungi to fresh healthy thalli and apothecia and the results of decay and damage were recorded.

Polysaccharides from lichen Xanthoria parietina: 1,4/1,6-α-d-glucans and a highly branched galactomannan with macrophage stimulating activity via Dectin-2 activation

Hot-water soluble polysaccharides H-1-3 and H-2-1 were isolated from the thalli of the lichen Xanthoria parietina (L.) Th. Fr. and purified by ion exchange and gel permeation chromatography. Structure elucidation was mainly based on 2D-NMR and nano-ESI-Q-TOF MS/MS experiments.H-1-3 (13.7 kDa) was shown to be linear α-glucan with α-d-Glcp-(1 → [→[4)-α-d-Glcp-(1]2 → [6)-α-d-Glcp-(1]3 → 4)]n core backbone. The (1,4)- and (1,6)-α-d-Glcp linkages were in a 2:3 M ratio.H-2-1 (525 kDa) was characterized as a complex branched β-galacto-α-mannan with →[6)-α-d-Manp-(1 → [2,6)-α-d-Manp-(1]2 → [2)-α-d-Manp-(1]2→]n core units and main side chains of (1,3)-β-d-Galf linked at O-6 to →2)-α-d-Manp-(1→, together with minor terminal units of 1,4/1,6-α-D -Glcp units attached to the core chain at O-6 position and α-L-Rhap linked to Galf side chain at O-2 position (Manp: Galf: Glcp: Rhap linkage ratio = 9:3:2:1).H-2-1 exerted strong immunoactivity in vitro and activated murine RAW macrophages 264.7 towards significantly increased phagocytosis, TNF-α and IL-1β secretion. These effects are due to an interaction of the galactomannan with the transmembrane pattern-recognition protein Dectin-2 of the macrophages.

Competition between heavy metal ions for binding sites in lichens: Implications for biomonitoring studies

The competitive behavior of divalent heavy metals (Cd, Cr, Pb, Zn) during cation uptake was investigated in the foliose lichen Xanthoria parietina. Lichen thalli were incubated with solutions containing 10 and 100 μM of CdCl2, CuCl2, and ZnCl2 as well as 5 and 50 μM of Pb(NO3)2, tested individually and in combination (Cd2++Cu2++Pb2++Zn2+). The analysis of molar concentrations suggests that a competition between cations for binding sites in X. parietina does exist. The decrease in net uptake between single and mixed solutions ranged between 14 and 29% at the lowest concentration and between 38 and 68% at the highest concentration. Furthermore, the uptake was proportionally lower for richer solutions. Each metal may behave differently when uptook: some (toxic elements) are preferentially stored at extracellular level (Cd, Pb), while others (micro-nutrients) are also present at intracellular level (Cu and Zn). The proportion between extracellular and total content changed for those elements accumulated also at intracellular level (Cu and Zn), while for Cd and Pb almost all the uptake occurred by passive mechanisms mainly at extracellular binding sites. The competition between metals for binding sites in the lichen surface entails that bioaccumulation data might result in an underestimation of some element levels measured in biomonitoring studies.

Toxicity of Diclofenac in the Fern Azolla filiculoides and the Lichen Xanthoria parietina.

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 100mg/L) and different exposure times (24, 48, 72 and 240h). 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 (100mg/L) and the longest time (240h). 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 (0.1mg/L) suggested a very limited susceptibility of these species to environmentally relevant levels of this pharmaceutical.

Short-term influence of Cu, Zn, Ni and Cd excess on metabolism, ultrastructure and distribution of elements in lichen Xanthoria parietina (L.) Th. Fr.

Lichens are symbiotic organisms that are very sensitive to heavy metal pollution. However, there is little evidence of how heavy metal pollution affects the physiological status, ultrastructural changes and distribution of elements in the layers of lichen thalli. For this purpose we simulated metal pollution to lichens and studied its impact on Xanthoria parietina. Thalli were treated with the heavy metals Cu, Zn, Ni, Cd in the form of sulfates at concentrations of 100µM and 500µM during 24, 48 and 72h. Untreated lichens served as controls. We assessed the status of physiological parameters (fluorescence and integrity of chlorophyll a, content of soluble proteins and ergosterol), ultrastructural changes, especially to the photobiont, and the distribution of elements in the layers of thalli in relation to treatment with heavy metals. We found positive correlations between the content of all tested heavy metals and the physiological response. We assessed the toxicity of the selected metals as follows: Cd >= Cu >= Ni > Zn, based on the effects on the photobiont layer in the lichen thallus and physiological measurements.

Physiological and ultrastructural effects of acute ozone fumigation in the lichen Xanthoria parietina: the role of parietin and hydration state.

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 1h with 3ppm 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.

Study of transplanted lichens with the use of physical methods: the case of Xanthoria parietina (L.) Th. Fr.

Electron paramagnetic resonance spectroscopy and inductively coupled plasma optical emission spectrometry were used to study the epiphytic lichen Xanthoria parietina (L.) Th. Fr. transplanted to natural and urbanized zones in the Moscow region. The combination of physical and lichenindication methods allowed us to determine periods as well as the magnitude of changes in the biophysical characteristics of the transplanted lichen in different environmental conditions. Electron paramagnetic resonance spectroscopy demonstrated that the number of paramagnetic centers in lichens transplanted to the natural zone did not change in comparison with initial value (2.6 ± 0.4)·1017 spin/mg) and remained stable after four weeks after transplantation. The number of paramagnetic centers in lichens transplanted to the urbanized zone increased by 1.1·1017 spin/mg by the end of the third week as compared with its initial value ((2.6 ± 0.4)·1017 spin/mg). Inductively coupled plasma optical emission spectrometry was used to measure concentration of iron, copper, manganese, magnesium, and zinc. We detected substantial changes in concentration of these elements during first four weeks after transplantation. For instance, concentration of copper in lichens transplanted to the urbanized zone increased from 7.5 ± 2.7 μg/g to 56.4 ± 8.6 μg/g by the end of the third week of the experiment.

Bioaccumulation, physiological and ultrastructural effects of glyphosate in the lichen Xanthoria parietina (L.) Th. Fr.

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.