Adaptations of cyanobacterium Nostoc commune to environmental stress: Comparison of morphological and physiological markers between European and Antarctic populations after rehydration

Availability of water may influence activities of all living organisms, including cyanobacterial communities. Filamentous cyanobacterium Nostoc commune is well adapted to wide spectrum of ecosystems. For this reason, N. commune had to develop diverse protection strategies due to exposition to regular rewetting and drying processes. Few studies have been conducted on activities, by which cyanobacteria are trying to avoid water deficit. Therefore, the present study using physiological and morphological parameters is focused on comparison between European and Antarctic ecotypes of N. commune during rewetting. Gradual increase of FV/FM ratios, as the markers of active PS II, demonstrated the recovery processes of N. commune colonies from Europe as well as from Antarctica after time dependent rehydration. During the initial hours of rewetting, there was lower content of soluble proteins in colonies from Antarctica in comparison to those from Europe. Total content of nitrogen was higher in European ecotypes of N. commune. Significantly higher frequency of occurrence of heterocysts in Antarctic ecotypes was observed. The heterocyst cells were significantly longer in Antarctic ecotypes rather than European ecotypes of N. commune

Contribution to the bryophyte flora of Antarctica: the James Ross Island moss inventory and the new records

The interest in distribution of bryophytes in Antarctica has increased in view of global climate warming and its effects in Antarctica. The moss flora of Antarctica is relatively rich, since only a small area (up to 1%) of this continent is not covered by ice. An immense space remains completely bryologically under-recorded. In this paper, we present a comprehensive moss list of James Ross Island (37 moss species). Two newly-recorded species are reported in our study: Bryum dichotomum and B. pallescens

Effects of acute NH3 air pollution on N-sensitive and N-tolerant lichen species

Lichens are sensitive to the presence of ammonia (NH3) in the environment. However, in order to use them as reliable indicators in biomonitoring studies, it is necessary to establish unequivocally the occurrence of certain symptoms following the exposure to NH3 in the environment. In this paper, we simulated an episode of acute air pollution due to the release of NH3. The biological effects of acute air pollution by atmospheric NH3 have been investigated using N-sensitive (Flavoparmelia caperata) and N-tolerant (Xanthoria parietina) species. Lichen samples were exposed to ecologically relevant NH3 concentrations for 8 weeks, simulating three areas of impact: a control area (2 μg/m(3)), an area of intermediate impact (2-35 μg/m(3)) and an area of high impact (10-315 μg/m(3)), with a peak of pollution reached between the fourth and fifth week. Ammonia affected both the photobiont and the mycobiont in F. caperata, while in X. parietina only the photosynthetic performance of the photobiont was altered after exposure to the highest concentration. In the photobiont of F. caperata we recorded chlorophyll degradation as indicated by OD435/415 ratio, decrease of the photosynthetic performance (as reflected by the maximum quantum yield of primary photochemistry FV/FM and the performance index PIABS); in the mycobiont, ergosterol reduction, membrane lipid peroxidation (as reflected by the increase of thiobarbituric acid reactive substances), alteration (decrease) of the secondary metabolite usnic acid. No effects were detected on caperatic acid and dehydrogenase activity. In X. parietina, the only signal determined by NH3 was the alteration of FV/FM and the performance index PIABS. The results suggest that physiological parameters in N-sensitive lichens well reflect the effects of NH3 exposure and can be applied as early indicators in monitoring studies

An insight into the variation of the antioxidative and antibacterial activity of extracts from populations of the subalpine and montane lichen Cetraria islandica

Lichens are supra-organismal symbiotic systems found in most environments. Environmental factors, such as temperature, altitude, precipitation, UV irradiation, or pathogens, significantly influence the physiology of lichens, and thus their secondary metabolism. The thalli of the same lichen species from different environments exhibit variation in the production of secondary metabolites and protective pigments. We selected two populations of the lichen Cetraria islandica from habitats differing in altitude, temperature, and precipitation. Then we compared their antioxidative and antibacterial activity. The lichen thalli were divided into two parts: the upper parts were exposed to light and the lower parts hidden from extensive radiation. The results show that the thalli from harsh alpine environments have higher 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging activity suggesting better tolerance to oxidative stress. On the other hand, the individuals from milder montane environments generally produce more secondary metabolites, leading to increased antibacterial activity of the extracts. The extracts of C. islandica containing fumarprotocetraric and paraconic acids exhibit inhibitory effects against gram-positive bacteria (e.g. Staphylococcus aureus) and some lower activity against gram-negative bacteria (e.g. Escherichia coli)

Uptake and toxicity of glyphosate in the lichen Xanthoria parietina (L.) Th. Fr

This study investigated if treatment of the lichen Xanthoria parietina (L.) Th. Fr. with glyphosate caused uptake of this herbicide as well as physiological alterations. Samples were treated with Glifene SL®, a common commercial glyphosate-based herbicide, at the lowest recommended doses (3.6 g/L) as well as with doses slightly higher than the highest suggested (36 g/L). The results clearly showed glyphosate uptake in X. parietina proportionally to the dose provided. Adverse physiological effects were evident on the photosynthetic apparatus (photosynthetic efficiency, chlorophyll a content, chlorophyll degradation) as well as on the fungal respiration rates and cell membrane integrity (ergosterol content, dehydrogenase activity) already after 24 h from treatment, also at the low application dose. It is concluded that lichens are suitable organisms for monitoring unwanted biological effects from the application of glyphosate-based herbicides, as well as for detecting the accumulation of this compound in the biota, thus screening for its environmental fate

Uptake and toxicity of glyphosate in the lichen Xanthoria parietina (L.) Th. Fr

5sireservedThis study investigated if treatment of the lichen Xanthoria parietina (L.) Th. Fr. with glyphosate caused uptake of this herbicide as well as physiological alterations. Samples were treated with Glifene SL®, a common commercial glyphosate-based herbicide, at the lowest recommended doses (3.6 g/L) as well as with doses slightly higher than the highest suggested (36 g/L). The results clearly showed glyphosate uptake in X. parietina proportionally to the dose provided. Adverse physiological effects were evident on the photosynthetic apparatus (photosynthetic efficiency, chlorophyll a content, chlorophyll degradation) as well as on the fungal respiration rates and cell membrane integrity (ergosterol content, dehydrogenase activity) already after 24 h from treatment, also at the low application dose. It is concluded that lichens are suitable organisms for monitoring unwanted biological effects from the application of glyphosate-based herbicides, as well as for detecting the accumulation of this compound in the biota, thus screening for its environmental fate.mixedVannini, Andrea; Guarnieri, Massimo; Bačkor, Martin; Bilová, Ivana; Loppi, StefanoVannini, Andrea; Guarnieri, Massimo; Bačkor, Martin; Bilová, Ivana; Loppi, Stefan