Lichens: might be considered as a source of gastroprotective molecules?

Indexación: Web of Science; ScieloABSTRACT Lichens are symbiotic relationship between fungi and algae or cyanobacteria. Secondary metabolites from lichens are known as lichen substances. We investigated depsidone and depside from lichens 1-6 in the context of their action to prevent gastric ulcer on the model of HCl/ethanol in mice for the first time. Doses of 30 mg/kg of lichen substances 1-6 and positive control (lansoprazole) significantly diminished the lesion index compared with negative control (treated only with HCl/EtOH). Lobaric acid 1, atranorin 2 and psoromic acid 5 reduced the gastric lesions by 76%, 63% and 65%, while for variolaric acid 3, diffractaic acid 4 and perlatolic acid 6 their values were 32%, 14% and 45%, respectively. Our results suggest that lichens have potential as a suite of gastroprotective molecules. Keywords: Lichens; depside; depsidone; gastric ulcer;http://ref.scielo.org/6949f

Lichens in the nests of European starling Sturnus vulgaris serve a mate attraction rather than insecticidal function

The European starling Sturnus vulgaris is a hole-nesting bird in which the male builds a voluminous nest using a wide variety of materials such as twigs, grass, leaves, feathers, and lichens. The function of lichens in starling nests has not been assessed until now and we hypothesize that this material is related to a mate attraction function or is used to protect nestlings from parasites due to the presence of secondary compounds with insecticidal effects with the lichens. We aimed to identify the lichen species and frequency of lichen use in European starling nests, and to determine if the presence of this material is correlated with mate attraction or with an insecticidal function. We found lichens in 45% of nests, mainly represented by Ramalina celastri. The lichens were added to the nests mainly before the beginning and at the end of nest building and egg-laying started earlier in nests with lichens than those without lichens. No association was found between the presence of lichen and the intensity of Philornis larvae (Diptera), a parasite that infests starling nestlings. Our results suggest that the addition of lichens could be related to mate attraction and a stimulus for the beginning of egg-laying but did not have an antiparasitic function in European starling nests.Fil: Ibañez, Lucía Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico Zoología Vertebrados; ArgentinaFil: García, Renato Andrés. Laboratorio de Entrenamiento Multidisciplinario para la Investigación Tecnológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fiorini, Vanina Dafne. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Montalti, Diego. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico Zoología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Ecology of endolithic lichens colonizing granite in continental Antarctica

In this study, the symbiont cells of several endolithic lichens colonizing granite in continental Antarctica and the relationships they have with the abiotic environment were analyzed in situ, in order to characterize the microecosystems integrating these lichens, from a microecological perspective. Mycobiont and photobiont cells, the majority classified as living by fluorescent vitality testing, were observed distributed through the fissures of the granite. The fact that extracellular polymeric substances were commonly observed close to these cells and the features of these compounds, suggest a certain protective role for these substances against the harsh environmental conditions. Different chemical, physical and biological relationships take place within the endolithic biofilms where the lichens are found, possibly affecting the survival and distribution of these organisms. The alteration of bedrock minerals and synthesis of biominerals in the proximity of these lichens give rise to different chemical microenvironments and suggest their participation in mineral nutrient cycling

Contrasting changes in palatability following senescence of the lichenized fungi Lobaria pulmonaria and L. scrobiculata

Epiphytic lichens can contribute significantly to ecosystem nutrient input because they efficiently accumulate atmospheric mineral nutrients and, in the case of cyanolichens, also fix nitrogen. The rate at which carbon and other nutrients gained by lichens enters the ecosystem is determined by lichen litter decomposability and by invertebrate consumption of lichen litter. In turn, these processes are driven by the secondary compounds present in senesced lichens. Therefore, we explored how lichen palatability and concentrations of secondary compounds change with tissue senescence for Lobaria pulmonaria, a green algal lichen with cyanobacterial cephalodia, and L. scrobiculata, a cyanobacterial lichen. During senescence both lichens lost 38-48% of their stictic acid chemosyndrome, while m-scrobiculin and usnic acid in L. scrobiculata remained unchanged. Snails preferred senesced rather than fresh L. pulmonaria, while senesced L. scrobiculata were avoided. This provides evidence that species with labile secondary compounds will have higher turnover rates, through consumption and decomposition, than those producing more stable secondary compounds

The lichen flora of Hull, with particular reference to zonal distribution and environmental monitoring

YesThe role of lichens as environmental monitors is widely recognised. Not only are they valuable as indicators of habitat stability and enyironmental continuity, but they are also effectiye in monitoring environmental quality. more particularly air and soil (and more recently water) pollution. In the past. the main role of lichens in this context has been to monitor sulphur dioxide air pollution. especially stable and rising levels (Seaward 1993). Howeyer, it has also been shown that lichens arc effective monitors of falling levels of gaseous sulphur dioxide and indeed of other pollutants. some of which are manifesting themselves as a consequence of the reduction in the former; of particular interest in this respect is the use of lichens to detect and determine the extent of qualitative changes in air pollution such as the impact of acid rain and hypertrophication (Seaward 1997: Seaward & Coppins 2(04)

Lichens and their importance for the monitoring of environmental changes in Southern Africa : with special reference to soil-inhabiting lichens.

Lichens are the object of investigation within the framework of the BIOTA Southern Africa project, subproject S04 (http://www.biota-africa.org). This interdisciplinary research project, installed in 2000, focuses on the analysis of biodiversity and its changes along climatic and vegetation gradients (transects) in Namibia and in the Republic of South Africa. In the context of this project, studies on the diversity of lichens are carriedout. Special reference is given to the monitoring of lichens growing on soil, which form the so called biological soil crusts.Lichen diversity is assessed and analysed with respect to its spatial and temporal changes. These are related to various abioticand biotic factors such as climate, soil features and land use. The indicator value of certain terricolouslichen taxaand/or lichen groups (communities) is investigated for the study area, and it is intended to use itin a future long-term monitoring programme in the region. In this brochure, we whish to explain what lichens are, how do they live and where do they grow, and why they are so important as bioindicatorsin arid and semi-arid areas of the world. The activities of the S04 subproject along the BIOTA transect are described, as well as the methods used for monitoring environmental changes in Southern Africa using soil-inhabiting lichens

Lichens in Forest Park and Nitrogenous Air Pollution

Lichens have been shown to be useful bioindicators for determining levels of nitrogen deposition related to air pollution. Preliminary lichen surveys in Forest Park in 2011 and 2012 revealed the presence of lichen species associated with high levels of nitrogenous pollution. The summer of 2013, we conducted lichen surveys at 25 permanent research sites that had been set up in Forest Park and the Ancient Forest Preserve in 1993. The majority of the lichens we collected at every site were classified as indicative of worst, poor, or fair air quality, with few lichens found that would indicate good or best air quality. Lobaria is a lichen common in Oregon and is important in the normal nitrogen cycle in forests. However, Lobaria is very sensitive to nitrogenous air pollution and is associated with the best air quality category. We only collected Lobaria at one site in the middle of the park. We found no significant differences in lichens in the different air quality variables in the various sections of the park, indicating that all of Forest Park is subjected to poor air quality

100 years of tropical bryophyte and lichen ecology : a bibliographic guide to the literature from 1901 - 2000

A list of 401 citations pertaining to the ecology of tropical bryophytes and lichens is presented. The bibliography includes publications addressing the biology, ecology, natural history, and physiology of bryophytes and lichens, but generally eschews taxonomic and floristic papers. All citations have been verified, unless denoted with an asterisk (*). An appendix that groups citations by category is provided

Isolation and characterization of microsatellites in the lichen Buellia frigida (Physciaceae), an Antarctic endemic

Premise of the study: Microsatellite markers were characterized for an Antarctic endemic, Buellia frigida, to investigate population structure and origin of Antarctic lichens. Methods and Results: Five primer sets were characterized. All loci were polymorphic with eight to 16 alleles per locus in a sample of 59 lichens. Conclusions: The microsatellite markers potentially provide insight into population structure and gene flow of B. frigida

Lichens of six vernal pools in Acadia National Park, ME, USA

Whereas lichen-habitat relations have been well-documented globally, literature on lichens of vernal pools is scant. We surveyed six vernal pools at Acadia National Park on Mount Desert Island, Maine, USA for their lichen diversity. Sixty-seven species were identified, including seven species that are new reports for Acadia National Park: Fuscidea arboricola, Hypogymnia incurvoides, Lepraria finkii, Phaeographis inusta, Ropalospora viridis, Usnea flammea, and Violella fucata. Five species are considered uncommon or only locally common in New England: Everniastrum catawbiense, Hypogymnia krogiae, Pseudevernia cladonia, Usnea flammea, and Usnea merrillii. This work represents the first survey of lichens from vernal pools in Acadia National Park and strongly suggests that previous efforts at documenting species at the Park have underestimated its species diversity. More work should be conducted to determine whether a unique assemblage of lichens occurs in association with this unique habitat type