Search

Lichens are symbiotic associations consisting of a photobiont (algae or cyanobacteria) and a mycobiont (fungus). They are known to produce a variety of unique secondary metabolites. To access this biosynthetic potential for biotechnological applications, deeper insights into the biosynthetic pathways and corresponding gene clusters are necessary. Here we provide a comprehensive view of the biosynthetic gene clusters of all organisms comprising a lichen thallus: fungi, green algae, and bacteria. We present two high-quality PacBio metagenomes, in which we identified a total of 460 biosynthetic gene clusters. Lichen mycobionts yielded 73–114 clusters, other lichen associated ascomycetes 8–40, green algae of the genus Trebouxia 14–19, and lichen-associated bacteria 101–105 clusters. The mycobionts contained mainly T1PKSs, followed by NRPSs, and terpenes; Trebouxia reads harbored mainly clusters linked to terpenes, followed by NRPSs and T3PKSs. Other lichen-associated ascomycetes and bacteria contained a mix of diverse biosynthetic gene clusters. In this study, we identified for the first time the biosynthetic gene clusters of entire lichen holobionts. The yet untapped biosynthetic potential of two species of the genus Hypogymnia is made accessible for further research. [ABSTRACT FROM AUTHOR]

Epiphytic lichens are well-known indicators of air contamination. The chemical composition of lichens is affected by the concentration of pollutants in the environment. Usually, researchers assess long-term variations in trace elements or other pollutants in the study area, or identify spatial features of air contamination. The aim of this study is to create a database of trace element concentrations in the samples of the epiphytic lichen Hypogymnia physodes growing in the Kaliningrad region. The database can be used as a "reference point" for monitoring studies. Another objective is to identify the spatial patterns of iron, manganese, nickel, cadmium, silver, lead, strontium, rubidium, and calcium in the Kaliningrad region. With the help of a regular grid, samples of wild lichens were collected from pine and birch trees, 1.2-1.8 m from their bases, in August 2010. One- to two-year-old thalli were used in the chemical analysis. The metals Ag, Cd, Cu, Pb, Ni, Fe, Mn, and Zn were determined by atomic absorption spectrometry AAS (Mn and Fe by flame atomic absorption FA AAS and the others by electro thermal atomisation ETA AAS); the elements Sr, Rb, and Ca were determined by X-ray fluorescence. The concentration of metals in the western coastal area (the Sambian or Kaliningrad Peninsula) is higher than it is in the central and eastern parts of the region. Principal component factor analysis was carried out to detect and characterise different pollution sources. The authors examined the features of spatial distribution of trace elements. The prevailing wind direction is between south and west; therefore, the highest concentrations of trace elements were found on the Sambian peninsula and on the coasts of the Vistula and Curonian Lagoons. The chemical composition of lichens on the Sambian peninsula may have developed under the impact of both local pollution sources--vehicles, thermal energy facilities, and ports--and such factors as trans-boundary traffic and sea spray. [ABSTRACT FROM AUTHOR]

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