Determining the physiological tolerance ranges of species is necessary to comprehend the limits of their responsiveness under strong abiotic pressures. For this purpose, the cosmopolitan moss (Hedw.) Brid.
View Article and Find Full Text PDFAshes from sugarcane by-product incineration were used to synthesize silica powders through alkaline hot extraction, followed by ethanol/acid precipitation or the sol-gel method. Both production methods allowed amorphous spherical silica microparticles with sizes ranging from 1-15 μm and 97% purity to be obtained. Water absorption ranged from 135-155 mL/100 g and 150-250 mL/100 g for precipitated silica and silica gel, respectively, while oil absorption ranged from 305 to 390 and from 250 to 350 mL/100 g.
View Article and Find Full Text PDFPoikilohydric autotrophs are the main colonizers of the permanent ice-free areas in the Antarctic tundra biome. Global climate warming and the small human footprint in this ecosystem make it especially vulnerable to abrupt changes. Elucidating the effects of climate change on the Antarctic ecosystem is challenging because it mainly comprises poikilohydric species, which are greatly influenced by microtopographic factors.
View Article and Find Full Text PDFDe-Man Rogosa and Sharpe (MRS) is a complex medium commonly used to obtain exopolysaccharides (EPS) from lactic acid bacteria. However, the various nutrients (carbon and nitrogen sources) of media and supplements added to enhance the bacterial growth and EPS production, may interfere with the purification of the extracts resulting in an over-estimation of the EPS and erroneous structural assignments. The efficiency of trichloroacetic acid (TCA)/pronase and 5-sulfosalicylic acid - SSA methods was evaluated.
View Article and Find Full Text PDFChronosequences at the forefront of retreating glaciers provide information about colonization rates of bare surfaces. In the northern hemisphere, forest development can take centuries, with rates often limited by low nutrient availability. By contrast, in front of the retreating Pia Glacier (Tierra del Fuego, Chile), a Nothofagus forest is in place after only 34 yr of development, while total soil nitrogen (N) increased from near zero to 1.
View Article and Find Full Text PDFThe majority of plant species are glycophytes and are not salt-tolerant and maintain low sodium levels within their tissues; if high tissue sodium concentrations do occur, it is in response to elevated environmental salt levels. Here we report an apparently novel and taxonomically diverse grouping of plants that continuously maintain high tissue sodium contents and share the rare feature of possessing symbiotic cyanobacteria. Leaves of in Tierra del Fuego always had sodium contents (dry weight basis) of around 4.
View Article and Find Full Text PDFThe Antarctic Peninsula has had a globally large increase in mean annual temperature from the 1951 to 1998 followed by a decline that still continues. The challenge is now to unveil whether these recent, complex and somewhat unexpected climatic changes are biologically relevant. We were able to do this by determining the growth of six lichen species on recently deglaciated surfaces over the last 24 years.
View Article and Find Full Text PDFKitoza refers to a traditional way of preparing beef and pork in Madagascar. However, in order to improve some drawbacks previous identified, the product was submitted to a reengineering process. The acceptance and sensory profiling of improved Kitoza products among Portuguese consumers was investigated.
View Article and Find Full Text PDFHere we report details of the European research initiative "Soil Crust International" (SCIN) focusing on the biodiversity of biological soil crusts (BSC, composed of bacteria, algae, lichens, and bryophytes) and on functional aspects in their specific environment. Known as the so-called "colored soil lichen community" (Bunte Erdflechtengesellschaft), these BSCs occur all over Europe, extending into subtropical and arid regions. Our goal is to study the uniqueness of these BSCs on the regional scale and investigate how this community can cope with large macroclimatic differences.
View Article and Find Full Text PDFBryophyte establishment represents a positive feedback process that enhances soil development in newly exposed terrain. Further, biological nitrogen (N) fixation by cyanobacteria in association with mosses can be an important supply of N to terrestrial ecosystems, however the role of these associations during post-glacial primary succession is not yet fully understood. Here, we analyzed chronosequences in front of two receding glaciers with contrasting climatic conditions (wetter vs drier) at Cordillera Darwin (Tierra del Fuego) and found that most mosses had the capacity to support an epiphytic flora of cyanobacteria and exhibited high rates of N2 fixation.
View Article and Find Full Text PDFExtracts were obtained from molasses, a byproduct of the sugar industry, via a number of chromatographic steps. Their antioxidant capacity was studied, including the inhibitory effect upon DNA oxidative damage; the phenolic compound profile thereof was ascertained as well. Two extracts exhibited significant antioxidant features, expressed by their capacity to decolorize ABTS radical cation and to scavenge hydroxyl free radicals (via deoxyribose assay).
View Article and Find Full Text PDFThis experiment was aimed at establishing, for the first time, the survival capability of lichens exposed to space conditions. In particular, the damaging effect of various wavelengths of extraterrestrial solar UV radiation was studied. The lichens used were the bipolar species Rhizocarpon geographicum and Xanthoria elegans, which were collected above 2000 m in the mountains of central Spain and as endolithic communities inhabiting granites in the Antarctic Dry Valleys.
View Article and Find Full Text PDFShade and irrigation are frequently used to increase the success of Mediterranean Quercus spp. plantations. However, there is controversy about the combined effects of these treatments on plant performance.
View Article and Find Full Text PDFChanges in the microbiological, physicochemical, and biochemical characteristics of Terrincho cheese as represented by native microflora, pH, water activity, soluble nitrogen fractions, free amino acids, and biogenic amines (e.g., ethylamine, dimethylamine, tryptamine, phenylethylamine, putrescine, cadaverine, histamine, tyramine, cystamine, and spermine) during ripening were monitored.
View Article and Find Full Text PDF• The cyanobionts of lichens and free-living Nostoc strains from Livingston Island (maritime Antarctica) were examined to determine both the cyanobiont specificity of lichens and the spatial distribution of Nostoc strains under extreme environmental conditions. • We collected five different lichen species with cyanobacteria as primary or secondary photobiont (Massalongia carnosa, Leptogium puberulum, Psoroma cinnamomeum, Placopsis parellina and Placopsis contortuplicata) and free-living cyanobacteria from different sample sites and analysed them using the tRNA (UAA) intron as a genetic marker to identify the cyanobacterial strains. • Our results showed that the same Nostoc strain was shared by all five lichen species and that an additional strain was present in two of the lichens.
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