The response of lichens inhabiting exposed wood of spruce logs to post-hurricane disturbances in Western Carpathian forests

We investigated which of the following environmental factors: the number of years since the windthrow of the tree (the age of dead wood), the phytocenosis (the type of forest community), altitude, exposure, wood hardness and the spatial scale of forest disturbances (small gaps with a few fallen spruces vs large-area windthrows) contributed to the diversity and abundance of lichens inhabiting the exposed wood of windthrown spruce trees in Polish Western Carpathian forests. Both Shannon H index and sum of coverage coefficients rose with increasing age of the wood, levelling off after 11–14 y (diversity) and 14–17 y (abundance). This factor appeared to be the most important for this group of lichens, but the significant positive impact of large-area windthrows on the lichen abundance was also demonstrated by using a GLM model. The age of the wood we precisely determined on the basis of data on Norway spruce mortality collected annually in permanent plots of the Gorce National Park since 2000. Using the Shore durometer we linked the course of the wood-inhabiting lichen succession with wood decay more precisely than before. The largest number of species was associated with medium hard wood, i.e., 51 < x ≤ 80 on the Shore scale. Based on the NMDS analysis, we distinguished four age groups of logs, differing in lichen abundance and defined by the dominance of distinctive species. A large number of usually corticolous lichen species used the wood of windthrown spruce logs as an optional habitat to survive large-scale, post-hurricane forest disturbances.     

Effect of low-humidity treatment on growth of the lichenParmotrema tinctorum in a growth cabinet

Low-humidity treatment triggered an increase of the thallus area and the chlorophyll content in the following high-humidity condition. When low-humidity treatment for 4 days was intercalated in high-humidity conditions every 16 days, the thallus area increased 40% in 76 days.     

Cultivation of the lichenParmotrema tinctorum in growth cabinets

The growth of lichens in the field is slow and their cultivation is generally thought to be difficult. We studied the effects of environmental conditions and culture solutions on the growth of a lichen, and found that growth ofParmotrema tinctorum (Nyl.) Hale in growth cabinets was possible. The thallus area increased by about 20% monthly when the lichen was soaked in a culture solution for 90 min every four days and then grown at 100% relative humidity when the temperature in the growth cabinet was 20C and illumination was at 12 W/m² for 16 hr daily.     

Studies on epiphytic flora of a tropical rain forest in Southwestern Nigeria

Bark microflora of 12 rainforest trees were examined. Crustose, foliose, and fruticose forms of lichens were observed. Bacillus sp., Erwinia sp., Micrococcus sp., Proteus sp., and Pseudomonas sp. were the five genera of bacteria recorded while three genera of Cyanobacteria; Entophysalis, Gleocapsa and Stigonema were observed. In the algal division, three genera of Chlorophyta found are Chlorococcum, Pleurococcus and Physolinum. Only one diatom, Cocconeis sp. was present on just one tree. Most of the epiphytic microflora found are mainly terrestrial and their spores might have been deposited on the barks by air, or dust-currents. While moisture is regarded as the most critical factor in growth of bark microflora, other factors like texture of the bark, insolation and especially chemical characteristics of the barks may play a key role in occurrence and distribution of micro-organisms on them.     

Hyphal walls of isolated lichen fungi

The hyphal walls of three mycobionts, isolated from the lichens Xanthoria parietina, Tornabenia intricata and Sarcogyne sp. were investigated by two techniques: microautoradiography of fungal colonies exposed to radioactive carbohydrate precursors; and binding, in vivo, of fluorescein conjugated lectins to hyphal walls of such colonies.N-[³H] acetylglucosamine was readily incorporated into tips, young hyphal walls and septa of the three mycobionts and the free-living fungus Trichoderma viride, but not into Phytophthora citrophthora, indicating that chitin is a major component of the mycobionts' hyphal walls. All three mycobionts, but neither of the free-living fungi, incorporated [³H] mannose and [³H] mannitol into their hyphal walls.Fluorescein-conjugated wheat germ agglutinin was bound to the hyphal walls of the three mycobionts and T. viride, but not to the walls of P. citrophthora; the binding pattern was similar to the grain pattern obtained in autoradiographs after short N-[³H] acetylglucosamine labelling. As wheat germ agglutinin binds specifically to chitin oligomers, the lectin binding tests further confirmed that chitin is a mycobiont hyphal wall component.Binding characteristics of several fluorescein-conjugated lectins to the three mycobionts indicated that this technique can yield useful information concerning the chemical composition of hyphal wall surfaces.List of abbreviations FITC fluorescein isothiocyanate - WGA wheat germ agglutinin - TCA trichloroacetic acid - PNA peanut agglutinin - LA lotus agglutinin - Glc NAc N-acetylglucosamine - ConA concanavalin A - SBA soybean agglutinin - WBA waxbean agglutinin Part of an M.Sc. thesis submitted by A. Braun to the Department of Botany, Tel Aviv University.     

A new depsidone of Lobaria pulmonaria with acetylcholinesterase inhibition activity

The phytochemical investigation conducted on a foliose lichen, Lobaria pulmonaria(L.) Hoffm. (Lobariaceae), led to the isolation of a new depsidone in the form of its diacetate derivative which showed a moderate acetylcholinesterase inhibition activity (1 µg) in vitro. This is the first record of identified depsidone structure in searching for these inhibitors.     

中国石蕊科地衣多样性与区系研究

通过实地调查我国华北、西南等地区的石蕊科地衣多样性,结合前人的研究资料,从物种多样性、生境、区系成分等多方面对我国石蕊科地衣进行研究。结果显示,我国石蕊科地衣共有5属107种,其中石蕊属(Cladonia)占优势,有94种,占石蕊科地衣总种数的87.9%。共鉴定出山西省新记录8种,云南省新记录种3种。石蕊科地衣生境共分为5种:藓丛生、树生、草地生、石生和多生境,其中多生境占比最高(49.5%)。我国石蕊科地衣区系成分多样共分为7种,包括:世界广布成分(除外)、环北极成分(37.8%)、泛热带成分(12.2%)、欧亚成分(6.1%)、东亚-北美成分(9.8%)、东亚成分(24.3%)和中国特有成分(9.8%)。     

PTP1B inhibitory effects of tridepside and related metabolites isolated from the Antarctic lichen Umbilicaria antarctica

The selective inhibition of PTP1B has been widely recognized as a potential drug target for the treatment of type 2 diabetes and obesity. In the course of screening for PTP1B inhibitory natural products, the MeOH extract of the dried sample of the Antarctic lichen Umbilicaria antarctica was found to exhibit significant inhibitory effect, and the bioassay-guided fractionation and purification afforded three related lichen metabolites 1-3. Compounds 1-3 were identified as gyrophoric acid (1), lecanoric acid (2), and methyl orsellinate (3) mainly by analysis of NMR and MS data. These compounds inhibited PTP1B activity with 50% inhibitory concentration values of 3.6 ± 0.04 μM, 31 ± 2.7 μM, and 277 ± 8.6 μM, respectively. Furthermore, the kinetic analysis of PTP1B inhibition by compound 1 suggested that the compound inhibited PTP1B activity in a non-competitive manner.     

Desiccation tolerance of the epilithic lichen Lecanora muralis (Schreb.) Rabenh. in the temperate climate

Lecanora muralis (Schreb.) Rabenh. is a ubiquitous epilithic crustose lichen of the temperate climate. It is well studied in terms of diel and annual carbon budget and productivity with continuous long-term observations in the field in 1995/96 by Otto L. Lange, Würzburg, and collaborators. However, these earlier studies left open the question to which extent the lichen is desiccation tolerant and if desiccation tolerance might possibly limit photosynthetic activity. In present study measurements of chlorophyll fluorescence parameters were performed to assess photosynthetic activity under various daily weather conditions throughout the year and recovery from desiccation after various periods of dryness in ambient air. Under any weather conditions, including strong frost for several days with night-temperatures around −15 °C and strong heat of several days with day-temperatures around 35 °C, the lichen was fully photosynthetically competent after wetting the samples for 15 min by submersion in water when they were dry in the field in the absence of actual incident precipitation. Chlorophyll fluorescence parameters were identical under all weather conditions sampled. A sample kept dry in ambient air for 37 days showed full recovery of chlorophyll fluorescence parameters after wetting for 30 min. Samples desiccated for longer periods up to 155 days took longer wetting times of about 300 min and recovered only partially but nevertheless showed active photosynthetic electron transport. Of 17 samples desiccated for 177–178 days only three recovered after rewetting for several days. It is concluded that the desiccation tolerance of L. muralis is sufficient to overcome dry spells of duration as it normally occurs in its natural environment. Desiccation tolerance is not likely to limit carbon budget and productivity.