The Estonian Mycological Collections of Heinrich August Dietrich (1820–1897)

Heinrich August Dietrich was a gardener with a deep interest in mycology. He published a two-volume monograph dealing with over 1,000 fungal and fungal-like taxa, the first cryptogamic research of this kind for the Baltic region. Between 1852 and 1857, H. A. Dietrich issued nine volumes of exciccatae named Centuria Plantarum Florae Balticae cryptogamarum. The preserved eight Centuriae and additional collections from Estonia (then the Imperial Russian Baltic province, Estonian Governorate) are revised and their current status in collections is presented. As a result, a new myxomycete species for Estonia, Physarum gyrosum, and the once doubtfully-reported species, Arcyria oerstedii, are recorded, and the earliest vouchers of some endangered ascomycetes, such as Poronia punctata and Sabuloglossum arenarium, are identified in his material. The most remarkable findings among lichenized fungi are Alectoria sarmentosa, Dibaeis baeomyces, Flavoparmelia caperata, Lasallia pustulata, Nephroma laevigatum, Peltigera venosa and Ramalina calicaris, as well as the oldest Estonian specimen of Lobaria pulmonaria.

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.

Accumulation of airborne microplastics in lichens from a landfill dumping site (Italy)

The aim of this study was to assess if lichens (Flavoparmelia caperata) surrounding a landfill dumping site in Italy accumulated higher amounts of microplastics compared with lichens at more distant sites. Lichen samples were collected at three sites along a transect from the landfill: close (directly facing the landfill), intermediate (200 m), and remote (1500 m). Anthropogenic microparticles (fibres and fragments) were determined visually after wet peroxide digestion of the samples, and microplastics were identified based on a hot needle test; the type of plastic was identified by micro-Raman analysis. The results showed that lichens collected in the vicinity of the landfill accumulated the highest number of anthropogenic microfibres and fragments (147 mp/g dw), and consequently microplastics (79 mp/g dw), suggesting that the impact of landfill emissions is spatially limited. The proportion of fibres and fragments identified as microplastics was 40% across all sites and the most abundant polymer type was polyester or polyethylene terephthalate (68%). These results clearly indicated that lichens can effectively be used to monitor the deposition of microplastics.

Host plant specificity of corticolous lichens in urban and suburban New Amsterdam, Berbice, Guyana

In this study, host plant - lichen specificity was investigated. Data was collected from 1000m2 sampling plots at each of four locations with an established 50m x 20m plot at each site. Forty-one trees from across five species were examined using (10cm by 50cm) ladder quadrats on tree trunks (N, S, E, W) at 150cm height. A total of 14978 individual lichens were identified that yielded 10 families, 13 genera and 18 species. Swietenia mahagoni showed the highest average corticolous lichen species composition, followed by Terminalia catappa and Melicoccus bijugales respectively. Cocos nucifera had a higher average species recorded than Mangifera indica. Crustose lichens were the most prominent corticolous lichens observed (61%) with the most individuals in Graphidaceae and Arthoniaceae. Foliose lichens (28%) showed the most abundance in Parmeliaceae, Caliciaceae and Collemataceae. Of the taxa recorded, 22.2% were restricted to specific trees. C. parasitica, H. laevigata, U. cornuta were restricted to S. mahagoni. D. applanata was restricted to C. nucifera. 22.2% of recorded species were found on all of the tree hosts that were examined. Bacidia laurocerasi, Flavoparmelia caperata, Flavoparmelia soredians and Graphina anguina. S. mahagoni hosted 88.9% of all recorded species. Swietenia mahagoni showed the highest average of recorded corticolous lichen species of all host trees with 7.58. Mangifera indica showed the lowest average with 4. The maximum number of species (10) was recorded on one S. mahagoni tree

Diversity of Lichen in Mangrove Forest of Tomoli Village Parigi Moutong Regency

Lichen is an organism resulting from a symbiotic association between fungi and algae in mutualistic symbiosis and eroticism, forming a morphological unity that is different from other species from its constituent components. This study aims to determine the level of lichen species diversity that grows in mangrove forests in Tomoli Village, Parigi Moutong Regency. This research was conducted in July 2019. The method used in this study was a survey method, the sampling technique was purposive sampling, namely by using a 10 cm x 10 cm plot on the mangrove trees in each path at the research location. The research results found ten types of lichen consisting of six genera, five families, seven orders, and four classes divided into two groups based on the kind of thallus, namely lichen crustose and foliose. The crustose lichen group is Aspicilia calcarea, Aspicilia sp, Pyrenula sp, Pyrenula dermatodes, Pyrenula santensis, Cryptothecia striata, Phaeographis sp, Graphis script, Verrucaria sp. Meanwhile, the foliose lichen group is Flavoparmelia caperata. The lichen diversity index value obtained in the mangrove forest in Tomoli Village was 2,225, indicating that the level of diversity is moderate.

How dry is dry? Molecular mobility in relation to thallus water content in a lichen

Lichens can withstand extreme desiccation to water contents of ≤ 0.1 g H2O g–1 DW, and in the desiccated state are among the most extremotolerant organisms known. Desiccation-tolerant life-forms such as seeds, mosses and lichens survive ‘vitrification’, that is the transition of their cytoplasm to a ‘glassy’ state, which causes metabolism to cease. However, our understanding of the mechanisms of desiccation tolerance is hindered by poor knowledge of what reactions occur in the desiccated state. Using Flavoparmelia caperata as a model lichen, we determined at what water contents vitrification occurred upon desiccation. Molecular mobility was assessed by dynamic mechanical thermal analysis, and the de- and re-epoxidation of the xanthophyll cycle pigments (measured by HPLC) was used as a proxy to assess enzyme activity. At 20 °C vitrification occurred between 0.12–0.08 g H2O g−1 DW and enzymes were active in a ‘rubbery’ state (0.17 g H2O g−1 DW) but not in a glassy state (0.03 g H2O g−1 DW). Therefore, desiccated tissues may appear to be ‘dry’ in the conventional sense, but subtle differences in water content will have substantial consequences on the types of (bio)chemical reactions that can occur, with downstream effects on longevity in the desiccated state.

Depigmenting potential of lichen extracts evaluated by in vitro and in vivo tests

Melanin is the main pigment of human skin, playing the primary role of protection from ultraviolet radiation. Alteration of the melanin production may lead to hyperpigmentation diseases, with both aesthetic and health consequences. Thus, suppressors of melanogenesis are considered useful tools for medical and cosmetic treatments. A great interest is focused on natural sources, aimed at finding safe and quantitatively available depigmenting substances. Lichens are thought to be possible sources of this kind of compounds, as the occurrence of many phenolic molecules suggests possible effects on phenolase enzymes involved in melanin synthesis, like tyrosinase. In this work, we used four lichen species, Cetraria islandica Ach., Flavoparmelia caperata Hale, Letharia vulpina (L.) Hue, and Parmotrema perlatum (Hudson) M. Choisy, to obtain extracts in solvents of increasing polarity, viz. chloroform, chloroform-methanol, methanol, and water. Cell-free, tyrosinase inhibition experiments showed highest inhibition for L. vulpina methanol extract, followed by C. islandica chloroform-methanol one. Comparable results for depigmenting activities were observed by means of in vitro and in vivo systems, such as MeWo melanoma cells and zebrafish larvae. Our study provides first evidence of depigmenting effects of lichen extracts, from tyrosinase inhibition to cell and in vivo models, suggesting that L. vulpina and C. islandica extracts deserve to be further studied for developing skin-whitening products.

Monitoring of Airborne Mercury: Comparison of Different Techniques in the Monte Amiata District, Southern Tuscany, Italy

In the present study, mercury (Hg) concentrations were investigated in lichens (Flavoparmelia caperata (L.) Hale, Parmelia saxatilis (L.) Ach., and Xanthoria parietina (L.) Th.Fr.) collected in the surrounding of the dismissed Abbadia San Salvatore Hg mine (Monte Amiata district, Italy). Results were integrated with Hg concentrations in tree barks and literature data of gaseous Hg levels determined by passive air samplers (PASs) in the same area. The ultimate goal was to compare results obtained by the three monitoring techniques to evaluate potential mismatches. Lichens displayed 180–3600 ng/g Hg, and Hg concentrations decreased exponentially with distance from the mine. Mercury concentration was lower than in Pinus nigra barks at the same site. There was a moderate correlation between Hg in lichen and Hg in bark, suggesting similar mechanisms of Hg uptake and residence times. However, correlation with published gaseous Hg concentrations (PASs) was moderate at best (Kendall Tau = 0.4–0.5, p > 0.05). The differences occurred because a) PASs collected gaseous Hg, whereas lichens and barks also picked up particulate Hg, and b) lichens and bark had a dynamic exchange with the atmosphere. Lichen, bark, and PAS outline different and complementary aspects of airborne Hg content and efficient monitoring programs in contaminated areas would benefit from the integration of data from different techniques.