Dlhawksworthia flavoparmeliae sp. nov., a new endolichenic fungus in Phaeosphaeriaceae

The genus Dlhawksworthia presently includes three species. All the previously described species have been isolated from plants. Besides, none of these three species have ever been recorded in China. We conducted surveys in various regions of China to isolate and identify endolichenic fungi associated with diverse lichen species. During these surveys, we isolated both previously known and undescribed fungi associated with lichens. Among these, there was an isolate of an unknown fungus. The morphological and molecular analyses indicated that this isolate represented a new species from the genus Dlhawksworthia. As a consequence, we described this fungus as Dlhawksworthia flavoparmeliae sp. nov. This is the first report of Dlhawksworthia isolated from a lichen in China and globally.

Bioactive Properties and Metabolite Profiles of Endolichenic Fungi in Mangrove Ecosystem of Negombo Lagoon, Sri Lanka

Endolichenic fungi (ELF) serve as a novel source of natural products with distinctive bioactivities. A total of 58 ELF isolated from 29 lichens collected from mangrove and mangrove-associated plants of Negombo lagoon, Sri Lanka were identified using morphological and DNA barcoding techniques. Ethyl acetate extracts of 18 such identified ELF isolates were subjected to in vitro assays to determine antioxidant, anti-inflammatory, tyrosinase inhibitory and antibacterial potency. Liquid chromatography–mass spectrometry (LC–MS) dereplication was conducted on the crude extracts in order to detect the secondary metabolites present. The extracts of Daldinia eschscholtzii and Hypoxylon lividipigmentum had the highest radical scavenging activity with SC50 values 14.27 ± 0.24 µg/mL and 18.34 ± 1.37 µg/mL, respectively. D. eschscholtzii also exhibited remarkable anti-inflammatory activity (IC50 7.97 ± 0.09 µg/mL). Tyrosinase inhibitory activity was highest in Cytospora xylocarpi (IC50 68.50 ± 0.34 µg/mL), while the highest activity against aerobic bacterial species Escherichia coli, Bacillus subtilis, Staphylococcus aureus and the anaerobic bacterial strain Streptococcus mutans was observed in the extracts of Xylaria feegenesis and Curvularia lunata. After a thorough study of the LC–MS profiles, it was found that the chemical profiles of Neofusicoccum occulatum, H. lividipigmentum and Myramaececium rubricosum were previously poorly explored in the literature.

Phylogenetic and morphological analyses of Coniochaeta isolates recovered from Inner Mongolia and Yunnan revealed three new endolichenic fungal species

Lichens are the result of a symbiotic interaction between fungi (mycobionts) and algae (phycobionts). Aside from mycobionts, lichen thalli can also contain non-lichenised fungal species, such as lichenicolous and endolichenic fungi. For this study, three surveys were conducted in China’s Yunnan Province and Inner Mongolia Autonomous Region between 2017 and 2020. Several samples of four lichen species were collected during these surveys: Candelaria fibrosa, Flavoparmelia caperata, Flavopunctelia flaventior and Ramalina sinensis. Six isolates of Coniochaeta were recovered from these four lichen species. The phylogenetic and morphological analyses revealed that two of these isolates were previously identified species, Coniochaeta velutinosa and C. acaciae. Those remaining were from potentially unknown species. We used molecular and morphological data to describe these previously-unknown species as Coniochaeta fibrosaesp. nov., C. mongoliaesp. nov. and C. sinensissp. nov. The findings of this study significantly improve our understanding of the variety and habitat preferences of Coniochaeta in China and globally.

PHYTOCHEMICAL STUDIES OF ENDOLICHENIC FUNGI ISOLATED FROM HYPOTRACHYNA INFIRMA (KUROK.) HALE

Objective: The aim of this study is to investigate of phytopharmaceutical importance of endolichenic fungi isolated from Hypotrachyna infirma (Kurok.) Hale. Methods: The lichen species were collected from Sholaiyar hills, Coimbatore and identified as Hypotrachyna infirma (Kurok.)Hale. From this lichen, 29 endolichenic fungi were isolated and 13 endolichenic fungi were identified. From the identified endolichenic fungi, 26 extracts were prepared by successive solvent extraction methods using Ethyl acetate and chloroform. Results: The phytochemical study revealed the presence of important constituents like Alkaloids, Tannins, Carbohydrates, Phenols, Protein, Terpenoids, Steroids, Glycosides Flavonoids and Saponins. From the 13 endolichenic fungi, only 5 endolichenic fungi (Nigrospora oryzae (Berkand Broome)Petch, Geotrichum candidum Link, Scytalidium lignicola pesante, Aspergillus oryzae(Ahlb.) cohn, Aspergillus niger Gr.) have more constitutents. These 5 endolichenic fungi have good results in Quantitative analysis also. Conclusion: Compared to ethyl acetate extracts Chloroform extracts showed very less concentration of the phytochemicals. From this study we conclutated Nigrospora oryzae (Berk and Broome) Petch gave the best results in both qualitative and quantitative compared to other endolichenic fungi.

The Chemistry and Pharmacology of Fungal Genus Periconia: A Review

Periconia is filamentous fungi belonging to the Periconiaceae family, and over the last 50 years, the genus has shown interest in natural product exploration for pharmacological purposes. Therefore, this study aims to analyze the different species of Periconia containing natural products such as terpenoids, polyketides, cytochalasan, macrosphelides, cyclopentenes, aromatic compounds, and carbohydrates carbasugar derivates. The isolated compound of this kind, which was reported in 1969, consisted of polyketide derivatives and their structures and was determined by chemical reaction and spectroscopic methods. After some years, 77 compounds isolated from endophytic fungus Periconia were associated with eight plant species, 28 compounds from sea hare Aplysia kurodai, and ten from endolichenic fungi Parmelia sp. The potent pharmacological agents from this genus are periconicin A, which acts as an antimicrobial, pericochlorosin B as an anti-human immunodeficiency virus (HIV), peribysin D, and pericosine A as cytotoxic agents, and periconianone A as an anti-inflammatory agent. Furthermore, information about taxol and piperine from Periconia producing species was also provided. Therefore, this study supports discovering new drugs produced by the Periconia species and compares them for future drug development.

Antimicrobial Compounds Isolated from Endolichenic Fungi: A Review

A lichen is a symbiotic relationship between a fungus and a photosynthetic organism, which is algae or cyanobacteria. Endolichenic fungi are a group of microfungi that resides asymptomatically within the thalli of lichens. Endolichenic fungi can be recognized as luxuriant metabolic artists that produce propitious bioactive secondary metabolites. More than any other time, there is a worldwide search for new antibiotics due to the alarming increase in microbial resistance against the currently available therapeutics. Even though a few antimicrobial compounds have been isolated from endolichenic fungi, most of them have moderate activities, implying the need for further structural optimizations. Recognizing this timely need and the significance of endolichenic fungi as a promising source of antimicrobial compounds, the activity, sources and the structures of 31 antibacterial compounds, 58 antifungal compounds, two antiviral compounds and one antiplasmodial (antimalarial) compound are summarized in this review. In addition, an overview of the common scaffolds and structural features leading to the corresponding antimicrobial properties is provided as an aid for future studies. The current challenges and major drawbacks of research related to endolichenic fungi and the remedies for them have been suggested.

Effect of Isolation Conditions on Diversity of Endolichenic Fungal Communities from a Foliose Lichen, Parmotrema tinctorum

Endolichenic fungi (ELF) are emerging novel bioresources because their diverse secondary metabolites have a wide range of biological activities. Metagenomic analysis of lichen thalli demonstrated that the conventional isolation method of ELF covers a very limited range of ELF, and the development of an advanced isolation method is needed. The influence of four variables were investigated in this study to determine the suitable conditions for the isolation of more diverse ELF from a radially growing foliose lichen, Parmotrema tinctorum. Four variables were tested: age of the thallus, severity of surface-sterilization of the thallus, size of a thallus fragment for the inoculation, and nutrient requirement. In total, 104 species (1885 strains) of ELF were isolated from the five individual thalli of P. tinctorum collected at five different places. Most of the ELF isolates belong to Sordariomycetes. Because each part of lichen thallus (of different age) has unique ELF species, the whole thallus of the foliose lichen is needed to isolate diverse ELF. Moderate sterilization is appropriate for the isolation of diverse ELF. Inoculation of small fragment (1 mm2) of lichen thallus resulted in the isolation of highest diversity of ELF species compared to larger fragments (100 and 25 mm2). Moreover, ELF species isolated from the small thallus fragments covered all ELF taxa detected from the medium and the large fragments in this study. The use of two media—Bold’s basal medium (nutrient poor) and potato dextrose agar (nutrient rich)—supported the isolation of diverse ELF. Among the tested variables, size of thallus fragment more significantly influenced the isolation of diverse ELF than other three factors. Species composition and richness of ELF communities from different lichen thalli differed from each other in this study.

Biodiscovery of Potential Antibacterial Diagnostic Metabolites from the Endolichenic Fungus Xylaria venustula Using LC–MS-Based Metabolomics

Three species of the lichen Usnea (U. baileyi (Stirt.) Zahlbr., U. bismolliuscula Zahlbr. and U. pectinata Stirt.) and nine associated endolichenic fungi (ELF) were evaluated using a metabolomics approach. All investigated lichen crude extracts afforded antibacterial activity against Staphylococcus aureus (minimum inhibitory concentration (MIC): 0.0625 mg/mL), but none was observed against Escherichia coli, while the ELF extract Xylaria venustula was found to be the most active against S. aureus (MIC: 2.5 mg/mL) and E. coli (MIC: 5 mg/mL). X. venustula was fractionated and tested for to determine its antibacterial activity. Fractions XvFr1 to 5 displayed bioactivities against both test bacteria. Selected crude extracts and fractions were subjected to metabolomics analyses using high-resolution LC–MS. Multivariate analyses showed the presence of five secondary metabolites unique to bioactive fractions XvFr1 to 3, which were identified as responsible for the antibacterial activity of X. venustula. The p-values of these metabolites were at the margin of significance level, with methyl xylariate C (P_60) being the most significant. However, their high variable importance of projection (VIP) scores (>5) suggest these metabolites are potential diagnostic metabolites for X. venustula for “dual” bioactivity against S. aureus and E. coli. The statistical models also showed the distinctiveness of metabolites produced by lichens and ELF, thus supporting our hypotheses of ELF functionality similar to plant endophytes.