Protist diversity and co-occurrence patterns obtained by metabarcoding of terricolous lichens, coastal cliffs and a microbial mat in the Atacama Desert, northern Chile.

Protists can endure challenging environments sustaining key ecosystem processes of the microbial food webs even under aridic or hypersaline conditions. We studied the diversity of protists at different latitudes of the Atacama Desert by massive sequencing of the hypervariable region V9 of the 18S rRNA gene from soils and microbial mats collected in the Andes. The main protist groups in soils detected in active stage through cDNA were cercozoans, ciliates, and kinetoplastids, while the diversity of protists was higher including diatoms and amoebae in the microbial mat detected solely through DNA. Co-occurrence networks from soils indicated similar assemblages dominated by amplicon sequence variants (ASVs) identified as Rhogostoma, Euplotes, and Neobodo. Microbial mat networks, on the other hand, were structured by ASVs classified as raphid-pennate diatoms and amoebae from the genera Hartmannella and Vannella, mostly negatively correlated to flagellates and microalgae. Additionally, our phylogenetic inferences of ASVs classified as Euplotes, Neobodo, and Rhogostoma were supported by sequence data of strains isolated during this study. Our results represent the first snapshot of the diversity patterns of culturable and unculturable protists and putative keystone taxa detected at remote habitats from the Atacama Desert.

Use of lichens as bioindicators of contamination by agrochemicals and metals.

The presence or absence of lichens serves as an indicator of the condition of an ecosystem and the degree to which it is contaminated by various agents, such as agrochemicals and metals. Evaluating the use of lichens as bioindicators of agrochemical contamination could provide a more comprehensive perspective of current contamination levels. Monitoring was conducted over a 4-month period in two study areas: one was a well-conserved area contaminated by metals, and the other was an area surrounded by agricultural crops contaminated by agrochemicals. Data on the presence and abundance of lichens in each study area were recorded at 10 monitoring points, a procedure that was repeated 16 times (every 15 days), and concentrations of heavy metals and "organophosphate" agrochemicals in the lichens collected were measured by means of Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES) and Gas Chromatography (GC), respectively. Generalized linear mixed models were used to assess abundance and richness, while general linear mixed models were used to attain Shannon diversity and Simpson dominance indices. Moreover, a multivariate analysis was performed in order to compare the lichen communities in both areas. The results indicated differences between the area contaminated by metals and that contaminated by agrochemicals in terms of abundance and Simpson's dominance index, while no differences were found in the case of the richness and diversity models. The PERMANOVA analysis additionally showed differences between the lichen communities in the two areas. The results also demonstrated that Canoparmelia caroliniana bioaccumulated metals in both areas. The levels of barium, cadmium, and sodium were higher in the area contaminated by metals, while concentrations of chromium and copper were higher in the area contaminated by agrochemicals. Finally, the concentrations of agrochemicals were higher in the area contaminated by agrochemicals and included toxic substances such as Methylparathion and Parathion, which are prohibited in Ecuador. In conclusion, this research underscores the importance of lichens as precise indicators of environmental health and contamination by agrochemicals and metals.

Diversity and distribution of the lichen genus Umbilicaria in the Argentine Islands-Kyiv Peninsula region, the maritime Antarctic.

This paper documents the occurrence of the genus Umbilicaria in the Argentine Islands-Kyiv Peninsula region of the Graham Coast in the maritime Antarctic. The presence of seven Umbilicaria species (U. africana, U. antarctica, U. aprina, U. decussata, U. kappenii, U. nylanderiana and U. umbilicarioides) in the ice-free areas of the Argentine Islands-Kyiv Peninsula region were confirmed. The species of U. africana and U. aprina are documented from the studied region for the first time. This study moves the southern distribution limit of U. africana about 300 km to the south: to the Argentine Islands-Kyiv Peninsula region. The distribution maps of Umbilicaria species for the studied region and maritime Antarctica are prepared.

Determination of phytochemical contents by LC/QTOF/MS and evaluation of in-vitro biological activities of 2 Peltigera lichens from Bursa.

Lichens are symbiotic associations of algae and fungi. They are edible as food and have been used in traditional medicine for years. It is aimed to screen Peltigera praetextata (Flörke ex Sommerf.) Zopfand and Peltigera elisabethae Gyeln. phytochemically by LC/QTOF/MS and according to the constituents to evaluate the antioxidant, tyrosinase inhibitory, and antibacterial activities. In total 54 of metabolites detected by LC/QTOF/MS were common in both species. According to LC/QTOF/MS scanning results, alkaloids, iridoid glycosides, phenolics, cyanogenetic glycosides, and terpenic structures were detected. DPPH, ABTS, superoxide radical scavenging activities, and metal chelating capacity IC50 values were 84.55, 9.349; 51.27, 9.127; 95.01, 58.65 and 20.57, 70.08 µg/mL., respectively. The CUPRAC reducing power was determined as 4.69 and 9.57 TEACCUPRAC, respectively. Tyrosinase inhibitor activity were found to be 86.95 and 196.7 µg/mL. Both lichens did not show antimicrobial effects. As a result of the antioxidant and tyrosinase inhibitor activities it was seen that their activities were significant and further in vivo studies could be carried out on this lichens.

Liquid chromatography-electrospray ionization-mass spectrometry/mass spectrometry characterization of depsides and depsidones from the Chilean lichen Parmotrema perlatum.

Lichens are recognized by their unique compounds and diverse applications in food, medicines, and cosmetics. Using ultra-high pressure liquid chromatography, coupled with a high-resolution mass spectrometer, metabolomic profiling of the lichen Parmotrema perlatum, from a methanolic extract, was performed. Based on characteristic fragmentation patterns, twenty-five lichenic substances were tentatively identified including 5 depsides, 12 depsidones, 2 diphenyl ethers, 1 aromatic considered as possible artifact, 1 dibenzofuran, 1 carbohydrate, 1 organic acid, and 2 undefined compounds. To the best of our knowledge, this is a more complete report of their phytochemistry from P perlatum. Our findings of the P perlatum profile may contribute and complement the current data of the Parmotrema genus.

Contribution of Mine-Derived Airborne Particulate Matter to Ca, Fe, Mn and S Content and Distribution in the Lichen Punctelia hypoleucites Transplanted to Bajo de la Alumbrera Mine, Catamarca (Argentina).

The aim of this work was to relate the contribution of mine-derived airborne particulate matter to Ca, Fe, Mn and S content and distribution in Punctelia hypoleucites transplanted to Bajo de la Alumbrera, an important open-pit mine in Catamarca, Argentina. Lichen samples were transplanted to four monitoring sites: two sites inside the mine perimeter and two sites outside the mine. After three months, elemental distribution in samples was analyzed by microparticle-induced X-ray emission (microPIXE), and elemental concentration was determined by specific techniques: Ca and Fe by instrumental neutron activation analysis, Mn by inductively coupled plasma atomic emission spectrometry and S by a turbidimetric method. A differential distribution of S and Ca in thalli transplanted in-mine sites was detected compared to that of samples transplanted outside-mine sites. An overlap of Fe and S in the upper cortex of the apothecium section was observed, leading to infer a mineral association of both elements. Similar association was observed for Ca and S. In addition to these results, the significantly higher concentration detected for S and Mn in in-mine site samples suggests a contribution of Fe, S, Ca and Mn of mining origin to the content and distribution of these elements in P. hypoleucites. MicroPIXE complemented with Mössbauer spectroscopy analysis determined the presence of pyrite particles together with other iron-bearing minerals displaying different degrees of oxidation. These results point to a mining origin of the airborne particulate matter trapped by the lichen thalli transplanted to Bajo de la Alumbrera. These findings indicate that P. Hypoleucites acts as an excellent air quality biomonitor in the Bajo de la Alumbrera mine area.

First molecular evidence of lichen-inhabiting Acrospermum and new insights into the evolution of lifestyles of Acrospermales (Dothideomycetes).

Acrospermales represent one of the least studied lineages of Dothideomycetes and are characterized by diverse ecological strategies, including saprotrophic, epiphytic, fungicolous, lichenicolous, and bryophilous lifestyles. The order is composed of two teleomorphic genera, Acrospermum and Oomyces, and five anamorphic genera of unclear relationships. The objectives of the study were to establish the phylogenetic position of Acrospermum species collected from lichens in the tropical forest of Bolivia and to infer the evolution of the lichenicolous lifestyle in Acrospermales. Our results reveal that the examined specimens from Bolivia represent a new species, A. bolivianum, which is well characterized by its phylogenetic distinctness, morphological characteristics, and host selection. The new species is the first lichenicolous member of Acrospermum and forms a well-supported clade sister to the bryophilous Acrospermum adeanum. The evolution of lifestyles, concluded by phylogenetic analyses and ancestral state reconstructions, indicated that the saprotrophic lifestyle is ancestral to Acrospermales. This corresponds to their close relationship to other saprotrophic lineages of Dothideomycetes and indicates that the wide spectrum of nutritional strategies, currently observed in Acrospermales, may be a result of more recent shifts in their ecology. Our results also suggest that the lichenicolous lifestyle in Acrospermales appeared independently at least two times. Lichenicolous species are represented in our data set by Acrospermum bolivianum and Gonatophragmium physciae, which evolved from lichenicolous and plant-parasite ancestors, respectively. The genus Oomyces, represented by O. carneoalbus, was included for the first time in the phylogenetic analysis and showed a sister relationship to the remaining taxa of Acrospermales.

Diversity patterns of vascular and non-vascular epiphytes along tropical dry forest / Patrones de diversidad de epífitas vasculares y no vasculares a lo largo del bosque seco tropical

Abstract Introduction: Epiphytes (vascular and non-vascular) are one of the most diverse groups in the Neotropics, but despite their importance in the functioning of many ecosystems, much of their taxonomy and ecology is still unknown in the dry forest of Colombia. Objective: To compare the diversity patterns and species composition of vascular and non-vascular epiphytes along tropical dry forest remnants of Cauca Valley, Colombia. Methods: Ten permanent plots (50 x 20 m2) were established in tropical dry forest remnants. The epiphytes were sampled in 40-50 trees per plot. Alpha and gamma diversity were calculated using the richness (q0) and Shannon index (q1) (alpha was estimated as the average for phorophytes). Beta diversity was measured using the Whitaker index. To evaluate the relationship between diversities and environmental variables, GLM analysis was used. Results: We found 50 morphospecies of vascular epiphytes, 77 of bryophytes and 290 of lichens. The 𝛼 and 𝛾 diversity of bryophytes from each remnant was significantly explained by temperature. The abundance of lichens per tree was significantly related with the DBH and tree height of each remnant. The 𝛼 diversity of vascular epiphytes shown can be explained by temperature and precipitation. The 𝛾 diversity was strongly influenced by the beta diversity in bryophytes and lichens. This pattern is because the sites with high disturbance present a lower diversity, as a consequence of a homogenizing effect, that is, a low turnover of species between sampling units. Conclusions: Precipitation and temperature affected the diversity of bryophytes and vascular epiphytes, while it did not show a relationship with the lichen's diversity, for which there is not a high congruence between the diversity and composition of these epiphytes.

Resumen Introducción: Los epífitos (vasculares y no vasculares) son uno de los más diversos grupos de plantas en el Neotrópico, pero a pesar de su importancia para el funcionamiento de varios ecosistemas, existen grandes vacíos en su conocimiento taxonómico y ecológico en el bosque seco de Colombia. Objetivo: Comparar los patrones de diversidad y composición de especies de epífitas vasculares y no vasculares a lo largo de remanentes de bosque seco tropical del Valle del Cauca, Colombia. Métodos: Se establecieron diez parcelas permanentes (50 x 20 m2) en remanentes de bosque seco tropical. Las epífitas se muestrearon en 40-50 árboles por parcela. La diversidad alfa y gamma se calculó utilizando la riqueza (q0) y el índice de Shannon (q1) (alfa se estimó como el promedio para los forófitos). La diversidad beta se midió utilizando el índice de Whitaker. Para evaluar la relación entre diversidades y variables ambientales se utilizó el análisis GLM. Resultados: Se encontraron 50 morfoespecies de epífitas vasculares, 77 de briófitas y 290 de líquenes. La diversidad de 𝛼 y 𝛾 de briófitas de cada remanente fue explicada significativamente por la temperatura. La abundancia de líquenes por árbol se relacionó significativamente con el DAP y la altura del árbol de cada remanente. La diversidad 𝛼 de epífitas vasculares que se muestra puede explicarse por la temperatura y la precipitación. La diversidad 𝛾 estuvo fuertemente influenciada por la diversidad beta en briófitas y líquenes. Este patrón se debe a que los sitios con alta perturbación presentan una menor diversidad, como consecuencia de un efecto homogeneizador, es decir, un bajo recambio de especies entre unidades de muestreo. Conclusiones: La precipitación y la temperatura afectaron la diversidad de briófitas y epífitas vasculares, mientras que no mostró relación con la diversidad de líquenes, por lo que no existe una alta congruencia entre la diversidad y composición de estas epífitas.

Biomarkers of pollution by glyphosate in the lichens, Parmotrema tinctorium and Usnea barbata.

Glyphosate is a herbicide commonly used in agriculture for weed control. Current agricultural production demands vast amounts of this product, which are applied by ground or aerial spraying. The concomitant aerial currents promote glyphosate drift to vegetated or urban areas. In this context, we hypothesized that the lichens, Parmotrema tinctorum and Usnea barbata, could be sensitive to the action of glyphosate and therefore be used to bio-indicate the presence of this herbicide in areas affected by drift. Since living organisms respond in different ways to the action of herbicides, our interest was also to indicate biological markers responsive to the action of glyphosate, through concentrations and exposure times of the thallus, besides identifying the most sensitive species. We evaluated the effect of different concentrations (0.0, 4.8, 9.6, and 19.2 mg L-1) and exposure times (24, 48, and 72 hours) to glyphosate on the morphoanatomy, photobiont vitality, photosynthetic efficiency, and oxidative metabolism of the thalli. We found that the lichens, P. tinctorum and U. barbata, respond to glyphosate stress, with prospects for use in the biomonitoring of pollutant dispersal from plantation areas. When using P. tinctorum as a bioindicator, lichen morphoanatomy, photobiont vitality, and photosynthetic pigment concentration were efficient biomarkers for the effect of concentration and exposure time. For U. barbata, the lichenic morphoanatomy and the activity of SOD and APX enzymes were essential tools to indicate the herbicide action. Parmotrema tinctotum, however, was characterized as more sensitive in bio-indicating the presence of this herbicide to diagnose the air quality in urban areas or vegetation sectors adjacent to agricultural environments.

Micro-CT imaging in species description: exploring beyond sclerotized structures in lichen moths (Lepidoptera: Erebidae, Arctiinae, Lithosiini).

X-ray micro-computed tomography imaging (micro-CT) is valuable for systematic research since it permits the non-destructive scanning and imaging of internal structures of very rare species and/or type specimens. Additionally, micro-CT allows to view the morphology and the functional anatomy of structures in their natural anatomical position, without deformations that typically occur using classical dissection protocols. In this study we provide the description of two new species of lichen moths (Lepidoptera: Erebidae, Lithosiini) from the Atlantic Forest in eastern Brazil: Nodozana heliae Moraes sp. nov. from Rio de Janeiro state and Epeiromulona pataxo Moraes & Aguiar sp. nov. from Bahia state. The male and female genitalia as well as the wing morphology were examined by means of non-destructive micro-CT, subsequent 3D model reconstruction, 360 degree spinning animations, 2D images from different angles, and those were compared against classical genitalia dissections from the same specimens. We conclude that techniques complement each other, micro-CT being particularly useful to study wing venation, sclerotized internal structures and muscles, while classical dissection is useful to study membranous structures, particularly in the female genitalia, abdominal skin and specialised scales on the male 8th sternite.

Vitality of mycobionts and photobionts after passing through the digestive tract of Constrictotermes cyphergaster (Isoptera) workers.

Termites are among the insects that consume lichens and may be potential dispersers of these symbionts. This study evaluated the vitality of photobionts and mycobionts after passing through the digestive tract of Constrictotermes cyphergaster. The percentage of live and dead algae was verified throughout the alimentary canal of 450 workers, originating from five sampled colonies in the Caatinga Dry Forest, NE, Brazil. A progressive growth in algae mortality was observed in the crop, paunch and rectum, however more than 40% of the algae found in faeces presented signs of vitality. Photobiont morphology was different between cells extracted from thallus in natura and algae present in termite faeces. The photobiont cells presented more shrunken cytoplasms after passing through the alimentary canal of C. cyphergaster. There was also an increase between the cell wall space and the cytoplasm membrane of algae found in the termite faecal pellets. Only four broken spores were found in the intestine, which made the vitality analysis unfeasible for these cells. The record of photobiont vitality in termite faecal pellets is indicative of endozoochoric dispersal, suggesting that this relationship between insects and lichens extends beyond a trophic interaction.

Assessment of Cytotoxic/Antitumour Potential and in silico Study of Salazinic Acid Isolated from Parmotrema concurrens.

INTRODUCTION: Despite numerous scientific advances, cancer continues to be one of the main causes of death in the world. This situation has driven the search for promising molecules. Lichen substances have been widely described for their pharmacological potential. OBJECTIVE: The present study evaluated the antitumour potential of a depsidone isolated from Parmotrema concurrens- salazinic acid (SAL) - through in vitro, in vivo and in silico studies. METHODS: The molecule was isolated from the acetonic extract of the lichen and recrystallized in acetone. The macrophage J774, sarcoma-180 and MDA-MB-231 cell lines were used for the MTT cytotoxicity assay. The antitumor assay used a murine model (Swiss albino mice) with sarcoma-180. The animals were treated for seven consecutive days with doses of SAL (25 and 50 mg/kg) and 5-fluorouracil (20 mg/kg). RESULTS: Its purity was determined using high-performance liquid chromatography (94%), and its structure was confirmed by H1 and C13 nuclear magnetic resonance. SAL was not considered toxic to cancer cell lines, showing cell viability rates of 79.49 ± 4.15% and 86.88 ± 1.02% for sarcoma-180 and MDA-MB-231, respectively. The tumour inhibition rate was greater than 80% in the animals treated with SAL and 65% for those that received 5-fluorouracil. Simulations of molecular dynamics to estimate the flexibility of the interactions between human thymidylate synthase and derivatives of SAL and 5-fluorouracil revealed that SAL exhibited greater enzymatic interaction capacity, with highly favourable energy, compared to 5-fluorouracil. CONCLUSION: The present results demonstrate the potential of salazinic acid as a tumour inhibition agent.

Antioxidant activity and enzymatic of lichen substances: A study based on cyclic voltammetry and theoretical.

The antioxidant activity of nine lichen substances, including methylatrarate (1), methyl haematommate (2), lobaric acid (3), fumarprotocetraric acid (4), sphaerophorin (5), subsphaeric acid (6), diffractaic acid (7), barbatolic acid (8) and salazinic acid (9) has been determined through cyclic voltammetry. The compounds 1-4 presented slopes close to the Nernst constant of 0.059 V, indicating a 2H+/2e- relation between protons and electrons, as long as the compounds 5, 6, 7, 8, and 9 present slopes between 0.037 V and 0.032 V, indicating a 1H+/2e- relation between protons and electrons. These results show a high free radical scavenging activity by means of the release of H+, suggesting an important antioxidant capacity of these molecules. Theoretical calculations of hydrogen bond dissociation enthalpies (BDE), proton affinities (PA), and Proton Transfer (PT) mechanisms, at M06-2x/6-311+G(d,p) level complement the experimental results. Computations support that the best antioxidant activity is obtained for the molecules (3, 4, 5, 6, 7 and 8), that have a carboxylic acid group close to a phenolic hydroxyl group, through hydrogen atomic transfer (HAT) and sequential proton loss electron transfer (SPLET) mechanisms. Additional computations were performed for modelling binding affinity of the lichen substances with CYPs enzymes, mainly CYP1A2, CYP51, and CYP2C9*2 isoforms, showing strong affinity for all the compounds described in this study.

Green ultrasound-assisted extraction of lichen substances from Hypotrachyna cirrhata. Ethyl lactate, a better extracting agent than methanol toxic organic solvent?

For the first time, we report a green extraction of lichen substances assisted by high power ultrasounds from Hypotrachyna cirrhata using ethyl lactate. This sustainable alternative was comparable, both in isolation and detection of lichen substances, to methanol. In the metabolomic analysis, a total of 77 lichen substances were detected comprising depsides, depsidones, dibenzofurans, organic acids, and lipids. Although the UHPLC/ESI/MS profiles were similar, the antioxidant activity was higher for the ethyl lactate extract. Ethyl lactate can replace toxic organic solvents, such as methanol, in order to provide more sustainable green chemistry methods.

A sustainable application for the extraction of lichen metabolites from Usnea cornuta: nontargeted metabolomics and antioxidant activity.

In this study, isolation and purification of lichen substances from Usnea cornuta were performed using conventional solvents, green solvents and green technologies. In addition, several lichen compounds were tentatively identified by UHPLC/ESI/MS/MS and usnic acid, diffractaic and galbinic acids were quantified as well. Limonene, ethyl lactate and methanol, were compared regarding their extraction properties and antioxidant capacities, determined by DPPH, ORAC, and FRAP assays. In the ethyl lactate, methanol and limonene extracts, 28 compounds in all, were detected for the first time by high resolution UHPLC-MS/MS fingerprinting. Untargeted metabolomics tentatively identified 14 compounds from the methanolic extract, 4 from limonene extract, and 20 metabolites from ethyl lactate extract. The green extract of ethyl lactate showed a similar antioxidant capacity to toxic methanol extract, except at ORAC assay where it was higher. Therefore, ethyl lactate can replace methanol, to provide more sustainable green chemistry methods.

Morpho-anatomical variations of Parmotrema pilosum (Parmeliaceae, Ascomycota) in fragmented forests of central Argentina: relationship between forest cover and distance to crops.

Forest vegetation is key for buffering microclimatic factors and regulating atmospheric deposition. Epiphytic lichens are sensitive to these factors and can indicate the overall health status of the ecosystem. Specifically, the analysis of morpho-anatomical variations allows us to understand the degree of tolerance or sensitivity of these organisms exposed to agricultural crops and how vegetation might buffer this response. We analyzed variations in vegetative and reproductive characters and injuries in thalli of Parmotrema pilosum as a response to distance to crops and forest cover. The study was conducted in forest patches of the Espinal in central Argentina, an ecosystem threatened by agricultural activity. We selected 10 sites with different forest cover areas and two collection points differing in distance to crops: sites adjacent to (0 m) and far from (150 m) crops. We collected five thalli from each collection point and analyzed variations in morpho-anatomical characters at macro- and microscopic levels. We found a lower number of algae and a higher proportion of simple cilia in individuals at points adjacent to crops. At points with low forest cover, a thinner upper cortex was observed, whereas at points with greater forest cover, an increase of necrosis and greater presence of apothecia were detected. Bleaching was the most frequent injury at sites adjacent to crops, decreasing with increasing forest cover. Conservation and reforestation of Espinal forest patches would promote the propagation of lichens affected by agricultural practices.

Biomarkers of pollution by glyphosate in the lichens, Parmotrema tinctorium and Usnea barbata / Biomarcadores da poluição por glifosato nos líquens Parmotrema tinctorium e Usnea barbata

Glyphosate is a herbicide commonly used in agriculture for weed control. Current agricultural production demands vast amounts of this product, which are applied by ground or aerial spraying. The concomitant aerial currents promote glyphosate drift to vegetated or urban areas. In this context, we hypothesized that the lichens, Parmotrema tinctorum and Usnea barbata, could be sensitive to the action of glyphosate and therefore be used to bio-indicate the presence of this herbicide in areas affected by drift. Since living organisms respond in different ways to the action of herbicides, our interest was also to indicate biological markers responsive to the action of glyphosate, through concentrations and exposure times of the thallus, besides identifying the most sensitive species. We evaluated the effect of different concentrations (0.0, 4.8, 9.6, and 19.2 mg L-1) and exposure times (24, 48, and 72 hours) to glyphosate on the morphoanatomy, photobiont vitality, photosynthetic efficiency, and oxidative metabolism of the thalli. We found that the lichens, P. tinctorum and U. barbata, respond to glyphosate stress, with prospects for use in the biomonitoring of pollutant dispersal from plantation areas. When using P. tinctorum as a bioindicator, lichen morphoanatomy, photobiont vitality, and photosynthetic pigment concentration were efficient biomarkers for the effect of concentration and exposure time. For U. barbata, the lichenic morphoanatomy and the activity of SOD and APX enzymes were essential tools to indicate the herbicide action. Parmotrema tinctotum, however, was characterized as more sensitive in bio-indicating the presence of this herbicide to diagnose the air quality in urban areas or vegetation sectors adjacent to agricultural environments.

O glifosato é um herbicida comumente utilizado na agricultura para o controle de ervas daninhas, contudo, a produção agrícola atual demanda quantidades gigantescas deste produto, que são aplicadas por pulverizações terrestres ou aéreas, que acompanhadas de correntes aéreas, promovem a deriva do glifosato para áreas vegetacionais ou urbanas. Neste contexto, nós levantamos a hipótese de que os líquens Parmotrema tinctorum e Usnea barbata pudessem ser sensíveis à ação do glifosato e, portanto, bioindicar a presença deste herbicida em áreas afetadas por deriva. Como os organismos vivos respondem de diferentes formas à ação dos herbicidas, nosso interesse foi também de indicar marcadores biológicos responsivos à ação do glifosato, por meio de concentrações e tempos de exposição dos talos, além de identificar a espécie mais sensível. Para isso, nós avaliamos o efeito de diferentes concentrações (0.0, 4.8, 9.6 e 19.2 mg L-1) e tempos de aexposição (24, 48 e 72 horas) ao glifosato, sobre a morfoanatomia, vitalidade do fotobionte, eficiência fotossintética e metabolismo oxidativo dos talos. Nós verificamos que os liquens P. tinctorum e U. barbata respondem ao estresse por glifosato, com perspectivas para serem utilizados no biomonitoramento da dispersão de poluentes a partir de áreas de plantio. Contudo, para o uso de P. tinctorum como bioindicador, a morfoanatomia liquênica, a vitalidade do fotobionte e a concentração de pigmentos fotossintéticos consistiram em biomarcadores eficientes para o efeito de concentração e tempo de exposição. Para U. barbata, a morfoanatomia liquênica, bem como a atividade das enzimas SOD e APX constituíram ferramentas importantes para evidenciar a ação do herbicida. A espécie P. tinctotum, contudo, foi caracterizada como mais sensível, sendo indicada para bioindicar a presença deste herbicida e para diagnosticar a qualidade do ar em áreas urbanas ou fragmentos vegetacionais imersos em matrizes agrícolas.

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.(AU)

Vitality of mycobionts and photobionts after passing through the digestive tract of Constrictotermes cyphergaster (Isoptera) workers / Vitalidade de micobiontes e fotobiontes após passagem pelo trato digestivo de operários de Constrictotermes cyphergaster (Isoptera)

Termites are among the insects that consume lichens and may be potential dispersers of these symbionts. This study evaluated the vitality of photobionts and mycobionts after passing through the digestive tract of Constrictotermes cyphergaster. The percentage of live and dead algae was verified throughout the alimentary canal of 450 workers, originating from five sampled colonies in the Caatinga Dry Forest, NE, Brazil. A progressive growth in algae mortality was observed in the crop, paunch and rectum, however more than 40% of the algae found in faeces presented signs of vitality. Photobiont morphology was different between cells extracted from thallus in natura and algae present in termite faeces. The photobiont cells presented more shrunken cytoplasms after passing through the alimentary canal of C. cyphergaster. There was also an increase between the cell wall space and the cytoplasm membrane of algae found in the termite faecal pellets. Only four broken spores were found in the intestine, which made the vitality analysis unfeasible for these cells. The record of photobiont vitality in termite faecal pellets is indicative of endozoochoric dispersal, suggesting that this relationship between insects and lichens extends beyond a trophic interaction.

Os térmitas estão entre os insetos consumidores de liquens e representam um potencial dispersor desses simbiontes. Este estudo avaliou a vitalidade de fotobiontes e micobiontes depois de terem passado pelo trato digestivo de Constrictotermes cyphergaster. O percentual de algas vivas e mortas foi verificado ao longo do canal alimentar de 450 operários, oriundos de cinco colônias amostradas em Caatinga Dry Forest, NE, Brazil. Um crescimento progressivo na mortalidade das algas foi observado no sentido papo, pança e reto, porém mais de 40% das algas presentes nas fezes apresentaram sinais de vitalidade. A morfologia dos fotobiontes foi diferente entre células extraídas de talos in natura e algas presentes nas fezes dos térmitas. As células do fotobionte apresentaram seu citoplasma mais encolhido, após a passagem pelo canal alimentar de C. cyphergaster. Também houve um aumento entre o espaço da parede celular e a membrana do citoplasma das algas encontradas nas pelotas fecais dos térmitas. Apenas quatro esporos quebrados foram encontrados no intestino dos cupins, o que inviabilizou a análise de vitalidade dessas células. O registro da vitalidade de fotobiontes nas pelotas fecais dos térmitas é um indicativo de dispersão endozoocórica, remetendo que a relação entre esses insetos e os liquens pode ir além de uma interação trófica.

Metabolomic Profiling, Antioxidant and Enzyme Inhibition Properties and Molecular Docking Analysis of Antarctic Lichens.

The lichen species Lecania brialmontii, Pseudephebe pubescens, and Sphaerophorus globosus are part of the prominent lichenoflora of the Antarctic territory. In this work, we report the metabolomic identification of ethanolic extracts of these species, their antioxidant and cholinesterase enzyme inhibitory activity, and conduct a molecular docking analysis with typical compounds. Eighteen compounds were identified by UHPLC-ESI-QTOF-MS in L. brialmontii, 18 compounds in P. pubescens, and 14 compounds in S. globosus. The content of phenolic compounds was variable among the species, ranging from 0.279 to 2.821 mg AG/g, and all three species showed high inhibition potential on the cholinesterase enzymes. Molecular docking showed important interactions between AChE and BChE with the selected compounds. This study evidences the chemical fingerprint of three species of the order Lecanorales that support the continuation of the study of other biological activities and their potential for medical research.