Research

19 pages, 5202 KiB

Open AccessArticle

Comprehensive Analysis of Secondary Metabolites in Usnea longissima (Lichenized Ascomycetes, Parmeliaceae) Using UPLC-ESI-QTOF-MS/MS and Pro-Apoptotic Activity of Barbatic Acid

by S. Divya Reddy, Bandi Siva, Katragunta Kumar, V. S. Phani Babu, Vemireddy Sravanthi, Joel Boustie, V. Lakshma Nayak, Ashok K Tiwari, CH. V. Rao, B. Sridhar, P. Shashikala and K. Suresh Babu

Molecules 2019, 24(12), 2270; https://doi.org/10.3390/molecules24122270 - 18 Jun 2019

Cited by 31 | Viewed by 4360

Abstract

Considering the importance of ultra-performance liquid chromatography-electrospray ionization-quadrupole time of flight-tandem mass spectrometry (UPLC-ESI-QTOF-MS/MS) hyphenated techniques for analysis of secondary metabolites from crude extracts, the present study was aimed at identification of secondary metabolites in acetone extract of the lichen Usnea longissima. [...] Read more.

Considering the importance of ultra-performance liquid chromatography-electrospray ionization-quadrupole time of flight-tandem mass spectrometry (UPLC-ESI-QTOF-MS/MS) hyphenated techniques for analysis of secondary metabolites from crude extracts, the present study was aimed at identification of secondary metabolites in acetone extract of the lichen Usnea longissima. From our study, 19 compounds were tentatively identified through comparison of exact molecular masses from their MS/MS spectra, mass fragmentation studies and comparison with literature data. In addition, potent cytotoxic activity of U. longissima extract prompted us to isolate four compounds, 18R-hydroxy-dihydroalloprotolichesterinic acid (19), neuropogolic acid (20), barbatic acid (21), and usnic acid (22) from this extract which were adequately identified through mass spectrometry and NMR spectroscopy. All four compounds displayed cytotoxic activity. Barbatic acid (21) manifested doxorubicin equivalent activity against A549 lung cancer cell line with IC₅₀ of 1.78 µM and strong G0/G1 accumulation of cells. Poly ADP-ribose polymerase (PARP) cleavage confirmed that it induced cytotoxic activity via apoptosis. Finally, our work has discerned the depside, barbatic acid (21) from crude extract as a candidate anti-cancer molecule, which induces cell death by stepping up apoptosis. Full article

(This article belongs to the Special Issue Lichens: Chemistry, Ecological and Biological Activities II)

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17 pages, 2361 KiB

Open AccessArticle

Usnic Acid Potassium Salt: Evaluation of the Acute Toxicity and Antinociceptive Effect in Murine Model

by Hallysson Douglas A. Araújo, José G. Silva Júnior, João R. Saturnino Oliveira, Maria Helena M. L. Ribeiro, Mônica C. Barroso Martins, Marcos A. Cavalcanti Bezerra, André Lima Aires, Mônica C. P. Azevedo Albuquerque, Mário R. Melo-Júnior, Nicodemos T. Pontes Filho, Eugênia C. Pereira, Diego J. Raposo Silva, Janaína V. dos Anjos, Emerson Peter S. Falcão, Nicácio H. Silva and Vera L. Menezes Lima

Molecules 2019, 24(11), 2042; https://doi.org/10.3390/molecules24112042 - 28 May 2019

Cited by 9 | Viewed by 3458

Abstract

To obtain usnic acid potassium salt (PS-UA), the usnic acid (UA) was extracted and purified from the lichen Cladonia substellata, and modified to produce PS-UA. The structure was determined by ¹H-NMR, IR and elemental analysis, ratified through computational models, as well [...] Read more.

To obtain usnic acid potassium salt (PS-UA), the usnic acid (UA) was extracted and purified from the lichen Cladonia substellata, and modified to produce PS-UA. The structure was determined by ¹H-NMR, IR and elemental analysis, ratified through computational models, as well as identification the site of K⁺ insertion in the molecule. Antinociceptive activity was detected through contortions in mice induced by acetic acid and formalin (phases I and II) after treatments with 10 and 20 mg/kg of PS-UA, indicating interference in both non-inflammatory and inflammatory pain. After oral administration at doses of 500, 1000 and 2000 mg/kg, no deaths of mice with treatments below 2000 mg/kg were observed. Except for body weight gain, food and water consumption decreased with treatments of 1000 and 2000 mg/kg, and the number of segmented leukocytes was higher for both treatments. Regarding serum levels, cholesterol and triglycerides decreased, however, there was an increase in hepatic transaminases with both treatments. Liver and kidney histological changes were detected in treatments of 2000 mg/kg, while the spleen was preserved. The PS-UA demonstrated antinociceptive activity while the acute toxicity at the concentration of 2000 mg/kg was the only dose that presented morphological changes in the liver and kidney. Full article

(This article belongs to the Special Issue Lichens: Chemistry, Ecological and Biological Activities II)

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11 pages, 753 KiB

Open AccessArticle

Mycosporine-Like Amino Acids (MAAs) in Time-Series of Lichen Specimens from Natural History Collections

by Marylène Chollet-Krugler, Thi Thu Tram Nguyen, Aurelie Sauvager, Holger Thüs and Joël Boustie

Molecules 2019, 24(6), 1070; https://doi.org/10.3390/molecules24061070 - 19 Mar 2019

Cited by 5 | Viewed by 3404

Abstract

Mycosporine-like amino acids (MAAs) were quantified in fresh and preserved material of the chlorolichen Dermatocarpon luridum var. luridum (Verrucariaceae/Ascomycota). The analyzed samples represented a time-series of over 150 years. An HPLC coupled with a diode array detector (HPLC-DAD) in hydrophilic interaction liquid chromatography [...] Read more.

Mycosporine-like amino acids (MAAs) were quantified in fresh and preserved material of the chlorolichen Dermatocarpon luridum var. luridum (Verrucariaceae/Ascomycota). The analyzed samples represented a time-series of over 150 years. An HPLC coupled with a diode array detector (HPLC-DAD) in hydrophilic interaction liquid chromatography (HILIC) mode method was developed and validated for the quantitative determination of MAAs. We found evidence for substance specific differences in the quality of preservation of two MAAs (mycosporine glutamicol, mycosporine glutaminol) in Natural History Collections. We found no change in average mycosporine glutamicol concentrations over time. Mycosporine glutaminol concentrations instead decreased rapidly with no trace of this substance detectable in collections older than nine years. Our data predict that a screening for MAAs in organism samples from Natural History Collections can deliver results that are comparable to those obtained from fresh collections only for some MAAs (e.g., mycosporine glutamicol). For other MAAs, misleading, biased, or even false negative results will occur as a result of the storage sensitivity of substances such as mycosporine glutaminol. Our study demonstrates the value of pilot studies with time-series based on model taxa with a rich representation in the Natural History Collections. Full article

(This article belongs to the Special Issue Lichens: Chemistry, Ecological and Biological Activities II)

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21 pages, 6026 KiB

Open AccessArticle

Biosynthetic Gene Content of the ‘Perfume Lichens’ Evernia prunastri and Pseudevernia furfuracea

by Anjuli Calchera, Francesco Dal Grande, Helge B. Bode and Imke Schmitt

Molecules 2019, 24(1), 203; https://doi.org/10.3390/molecules24010203 - 08 Jan 2019

Cited by 32 | Viewed by 6543

Abstract

Lichen-forming fungi produce a vast number of unique natural products with a wide variety of biological activities and human uses. Although lichens have remarkable potential in natural product research and industry, the molecular mechanisms underlying the biosynthesis of lichen metabolites are poorly understood. [...] Read more.

Lichen-forming fungi produce a vast number of unique natural products with a wide variety of biological activities and human uses. Although lichens have remarkable potential in natural product research and industry, the molecular mechanisms underlying the biosynthesis of lichen metabolites are poorly understood. Here we use genome mining and comparative genomics to assess biosynthetic gene clusters and their putative regulators in the genomes of two lichen-forming fungi, which have substantial commercial value in the perfume industry, Evernia prunastri and Pseudevernia furfuracea. We report a total of 80 biosynthetic gene clusters (polyketide synthases (PKS), non-ribosomal peptide synthetases and terpene synthases) in E. prunastri and 51 in P. furfuracea. We present an in-depth comparison of 11 clusters, which show high homology between the two species. A ketosynthase (KS) phylogeny shows that biosynthetic gene clusters from E. prunastri and P. furfuracea are widespread across the Fungi. The phylogeny includes 15 genomes of lichenized fungi and all fungal PKSs with known functions from the MIBiG database. Phylogenetically closely related KS domains predict not only similar PKS architecture but also similar cluster architecture. Our study highlights the untapped biosynthetic richness of lichen-forming fungi, provides new insights into lichen biosynthetic pathways and facilitates heterologous expression of lichen biosynthetic gene clusters. Full article

(This article belongs to the Special Issue Lichens: Chemistry, Ecological and Biological Activities II)

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16 pages, 4519 KiB

Open AccessArticle

Nitrogen-Fixing Bacteria Associated with Peltigera Cyanolichens and Cladonia Chlorolichens

by Katerin Almendras, Jaime García, Margarita Carú and Julieta Orlando

Molecules 2018, 23(12), 3077; https://doi.org/10.3390/molecules23123077 - 25 Nov 2018

Cited by 22 | Viewed by 4400

Abstract

Lichens have been extensively studied and described; however, recent evidence suggests that members of the bacterial community associated with them could contribute new functions to the symbiotic interaction. In this work, we compare the nitrogen-fixing guild associated with bipartite terricolous lichens with different [...] Read more.

Lichens have been extensively studied and described; however, recent evidence suggests that members of the bacterial community associated with them could contribute new functions to the symbiotic interaction. In this work, we compare the nitrogen-fixing guild associated with bipartite terricolous lichens with different types of photobiont: Peltigera cyanolichens and Cladonia chlorolichens. Since cyanobacteria contribute nitrogen to the symbiosis, we propose that chlorolichens have more diverse bacteria with the ability to fix nitrogen compared to cyanolichens. In addition, since part of these bacteria could be recruited from the substrate where lichens grow, we propose that thalli and substrates share some bacteria in common. The structure of the nitrogen-fixing guild in the lichen and substrate bacterial communities of both lichens was determined by terminal restriction fragment length polymorphism (TRFLP) of the nifH gene. Multivariate analyses showed that the nitrogen-fixing bacteria associated with both types of lichen were distinguishable from those present in their substrates. Likewise, the structure of the nitrogen-fixing bacteria present in the cyanolichens was different from that of chlorolichens. Finally, the diversity of this bacterial guild calculated using the Shannon index confirms the hypothesis that chlorolichens have a higher diversity of nitrogen-fixing bacteria than cyanolichens. Full article

(This article belongs to the Special Issue Lichens: Chemistry, Ecological and Biological Activities II)

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18 pages, 2301 KiB

Open AccessArticle

Carbon Consumption Patterns of Microbial Communities Associated with Peltigera Lichens from a Chilean Temperate Forest

by Katerin Almendras, Diego Leiva, Margarita Carú and Julieta Orlando

Molecules 2018, 23(11), 2746; https://doi.org/10.3390/molecules23112746 - 24 Oct 2018

Cited by 10 | Viewed by 3676

Abstract

Lichens are a symbiotic association between a fungus and a green alga or a cyanobacterium, or both. They can grow in practically any terrestrial environment and play crucial roles in ecosystems, such as assisting in soil formation and degrading soil organic matter. In [...] Read more.

Lichens are a symbiotic association between a fungus and a green alga or a cyanobacterium, or both. They can grow in practically any terrestrial environment and play crucial roles in ecosystems, such as assisting in soil formation and degrading soil organic matter. In their thalli, they can host a wide diversity of non-photoautotrophic microorganisms, including bacteria, which play important functions and are considered key components of the lichens. In this work, using the BioLog^® EcoPlate system, we studied the consumption kinetics of different carbon-sources by microbial communities associated with the thallus and the substrate of Peltigera lichens growing in a Chilean temperate rain forest dominated by Nothofagus pumilio. Based on the similarity of the consumption of 31 carbon-sources, three groups were formed. Among them, one group clustered the microbial metabolic profiles of almost all the substrates from one of the sampling sites, which exhibited the highest levels of consumption of the carbon-sources, and another group gathered the microbial metabolic profiles from the lichen thalli with the most abundant mycobiont haplotypes. These results suggest that the lichen thallus has a higher impact on the metabolism of its microbiome than on the microbial community of its substrate, with the latter being more diverse in terms of the metabolized sources and whose activity level is probably related to the availability of soil nutrients. However, although significant differences were detected in the microbial consumption of several carbon-sources when comparing the lichen thallus and the underlying substrate, d-mannitol, l-asparagine, and l-serine were intensively metabolized by both communities, suggesting that they share some microbial groups. Likewise, some communities showed high consumption of 2-hydroxybenzoic acid, d-galacturonic acid, and itaconic acid; these could serve as suitable sources of microorganisms as bioresources of novel bioactive compounds with biotechnological applications. Full article

(This article belongs to the Special Issue Lichens: Chemistry, Ecological and Biological Activities II)

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12 pages, 2965 KiB

Open AccessFeature PaperArticle

tert-Butylphenolic Derivatives from Paenibacillus odorifer—A Case of Bioconversion

by Thi-Bach-Le Nguyen, Olivier Delalande, Isabelle Rouaud, Solenn Ferron, Laura Chaillot, Rémy Pedeux and Sophie Tomasi

Molecules 2018, 23(8), 1951; https://doi.org/10.3390/molecules23081951 - 05 Aug 2018

Cited by 5 | Viewed by 4656

Abstract

Two compounds (1) and (2) containing tert-butylphenol groups were, for the first time, produced during the culture of Paenibacillus odorifer, a bacterial strain associated with the crustose lichen, Rhizocarpon geographicum. Their entire structures were identified by [...] Read more.

Two compounds (1) and (2) containing tert-butylphenol groups were, for the first time, produced during the culture of Paenibacillus odorifer, a bacterial strain associated with the crustose lichen, Rhizocarpon geographicum. Their entire structures were identified by one-dimensional (1D) and two-dimensional (2D) NMR and high-resolution electrospray ionisation mass spectrometry (HRESIMS) spectroscopic analyses. Among them, Compound 1 exhibited significant cytotoxicity against B16 murine melanoma and HaCaT human keratinocyte cell lines with micromolar half maximal inhibitory concentration (IC₅₀) values. Furthermore, after supplementation studies, a putative biosynthesis pathway was proposed for Compound 1 throughout a bioconversion by this bacterial strain of butylated hydroxyanisole (BHA), an antioxidant polymer additive. Full article

(This article belongs to the Special Issue Lichens: Chemistry, Ecological and Biological Activities II)

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8 pages, 1112 KiB

Open AccessCommunication

Can Parietin Transfer Energy Radiatively to Photosynthetic Pigments?

by Beatriz Fernández-Marín, Unai Artetxe, José María Becerril, Javier Martínez-Abaigar, Encarnación Núñez-Olivera and José Ignacio García-Plazaola

Molecules 2018, 23(7), 1741; https://doi.org/10.3390/molecules23071741 - 17 Jul 2018

Cited by 4 | Viewed by 4010

Abstract

The main role of lichen anthraquinones is in protection against biotic and abiotic stresses, such as UV radiation. These compounds are frequently deposited as crystals outside the fungal hyphae and most of them emit visible fluorescence when excited by UV. We wondered whether [...] Read more.

The main role of lichen anthraquinones is in protection against biotic and abiotic stresses, such as UV radiation. These compounds are frequently deposited as crystals outside the fungal hyphae and most of them emit visible fluorescence when excited by UV. We wondered whether the conversion of UV into visible fluorescence might be photosynthetically used by the photobiont, thereby converting UV into useful energy. To address this question, thalli of Xanthoria parietina were used as a model system. In this species the anthraquinone parietin accumulates in the outer upper cortex, conferring the species its characteristic yellow-orange colouration. In ethanol, parietin absorbed strongly in the blue and UV-B and emitted fluorescence in the range 480–540 nm, which partially matches with the absorption spectra of photosynthetic pigments. In intact thalli, it was determined by confocal microscopy that fluorescence emission spectra shifted 90 nm towards longer wavelengths. Then, to study energy transfer from parietin, we compared the response to UV of untreated and parietin-free thalli (removed with acetone). A chlorophyll fluorescence kinetic assessment provided evidence of UV-induced electron transport, though independently of the presence of parietin. Thus, a role for anthraquinones in energy harvesting is not supported for X. parietina under presented experimental conditions. Full article

(This article belongs to the Special Issue Lichens: Chemistry, Ecological and Biological Activities II)

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