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The use of biodiesel blends with petroleum diesel in vehicular engines demands the evaluation of the possible impacts and effects of the gases emitted from their combustion on the environment. Among studies on these questions, biomonitoring using lichens is a viable alternative, given their interactions with the elements dispersed in the atmosphere, as well as its sensitivity and capacity to retain contaminants. In this study, we analyzed the effects of gas emissions from the combustion of biodiesel mixture with petroleum diesel on Cladonia verticillaris thalli. Samples of the lichen (10 g) were exposed to the gases emitted by the exhaust of the generator engine during the combustion process of biodiesel mixtures to petroleum diesel (7% (B7), 10% (B10), 40% (B40), 50% (B50), and 70% (B70)). At 90 days after exposure, samples were analyzed for n-alkane profiles, thallus morphology, photosynthetic pigment contents, and secondary lichen metabolites (protocetraric and fumarprotocetraric acids). Sets B7 and B10 showed better resistance of the lichen to pollutants. Set B40 showed a high stress evidenced by the chain elongation of n-alkanes structure and high chlorophyll production, presenting high morphological damages when compared to the control sets, B7 and B10. The results showed significant reductions of n-alkanes profiles for mixtures with high concentrations of biodiesel (B50 and B70), as well as decreases in the chlorophyll content. These groups showed an increase in the synthesis of secondary metabolites, corroborating the hypothesis that high concentrations of biodiesel in the mixture with petroleum diesel have greater impacts on the lichen., Depto. de Genética, Fisiología y Microbiología, Fac. de Ciencias Biológicas, TRUE, pub

Lichens are the symbiotic organisms formed by one species of fungus associated to one or more species of green algae and/or cyanobacteria. The relationship between these organisms results in a metabolism that culminates in a production of exclusive compounds, named lichen substances, also known as lichen compounds or lichen acids. These products are known to exhibit several biological properties, and can be effective against several diseases. Several species of lichens found in Brazil have been identified and characterized for their bioactives during the last few decades. Studies have shown that these species possess antimicrobial, antineoplastic, anti-inflammatory, anti-leishmanial, and many more such bioactivities. In most cases, the articles mention different mechanisms of action. In complement, biotechnological studies have been carried out to achieve a continuous production of bioactive compounds, for example, the use of small amounts of thallus, collected directly from the environment, bioconservation processes, nanotechnological assays, nano and microencapsulations for a controlled drug liberation, incorporation in polymer matrix for pharmacological uses, etc. The possibility of extensive use of lichen substances encourages for further studies in this field, including the Brazilian species.

The aim of this paper is related to the modifications of the most usual method for producing USN and others bioactive compounds by the lichen Cladonia substellata to rationalize ecologically the provision of those at large scale. Different cell immobilization systems were assayed, using NaOAc as biosynthetic precursor at different concentrations. The introduced new systems to the most usual, consisting of the static incubation of immobilizates, were bioreactors in rotary movement and in continuous flow of precursor. They clearly enhance the production of USN. In addition, the kind of immobilization system can vary the content of produced metabolites. The occurrence of reduced USN and the occurrence of both NTI and STI acids in the cell washes were correlated. In this way, the modification of immobilization technique leads to highest production of these metabolites, and to a better use of the precursor, but it does not show any significant influence on the production of accessory and/or degraded compounds of the chemical species. On the basis of our results, USN and other compounds from C. substellata were produced in substantial amounts by kaolinite-immobilized continuous flow system and, in a general way, at a concentration of 10.0 mM, using NaOAc as precursor., National Council for Scientific and Technological Development (CNPq, Brazil), Depto. de Genética, Fisiología y Microbiología, Fac. de Ciencias Biológicas, TRUE, pub

Cladonia verticillaris (Raddi) Fr. is a lichen species that grows on sandy soil of tablelands coexisting with savannah-like vegetation in Brazil. This species produces different lichen phenolics that are leached to the soil by the rainwater and exhibit several biological activities that could affect the habitat. The effect of soil moisture in the retention and percolation of proteins, protocetraric acid (PRO) and fumarprotocetraric acid (FUM), the main phenolics produced from C. verticillaris, was analyzed in this work. Proteins were retained in dry soil but they percolated when the soil was water-saturated. FUM was strongly retained in this kind of acidic soils and transformed into PRO by spontaneous hydrolysis when the soil moisture increased. This study demonstrates that proteins, PRO and FUM that were effectively leached to the soil, retained, transformed or percolated to deeper soil layers depending on the amount of previous rainfall. This fact must be taken into account in order to consider the biological effects of these substances on the vegetation of coastal tableland Brazil., Universidad Complutense de Madrid, CNPq, Brazil, Programa Especial de CooperaÁao Internaciona, Depto. de Genética, Fisiología y Microbiología, Fac. de Ciencias Biológicas, TRUE, pub

The lichen Cladonia verticillaris can alter the mineralogical composition of the sandy soils that serve as its main substrate. Soils from Mamanguape, the semiarid land of the northeast of Brazil on which C. verticillaris grows, are mainly composed by silica and traces of microcline and muscovite. Sometimes, solid particles from these soils appear inside the thallus but it is not known if their chemical composition is identical to that of the soil from which they come or the lichen has modified them. The lichen produces organic acids (oxalic and malic acids) and several phenolics (atranorin, and protocetraric and fumarprotocetraric acids) that form salts and chelates by extracting some cations (Ca2+, Mg2+, Al3+) from the mineral substrate (silica). In addition, solid soil particles can be involved by the growing thallus and stored in the interhyphal spaces. There is no any previous reference, up to where we know, on the existence of mineral inclusions in thalli of fruticose lichens. The aim of this work is, therefore, to determine if such modifications have really been carried out. Mineral particles inside the thallus consist of silica, wollastonite, and feldspars. We propose that silica and microcline particles were captured from soil by growing thalli of C. verticillaris and then modified inside the thalli by action of lichen metabolites. Formation of monoclinic orthoclase (KAlSi3O8) necessarily requires partial solubilization and re-crystallization of triclinic microcline (KAlSi3O8) in the interhyphal spaces. De novo formation of wollastonite (CaSiO3) requires extraction by lichen phenolics of the calcium for muscovite and the resulting chelates could exchange the cation with the components of the mineral particles, preferably silica, to produce calcium silicates. Moreover, silica intrathalline particles, almost similar to diatom skeleton, also occur and this supports the oceanic origin on these sandy soils., Ministerio de Ciencia e Innovación (MICINN), Coordenadoira de Aperfeçioamento de Pessoal de Ensino Superior (CAPES, Brazil), Conselho Nacional de Desenvolvimento Científico e Tecnológico (VNPq, Brazil), Depto. de Genética, Fisiología y Microbiología, Fac. de Ciencias Biológicas, TRUE, pub

The possibilities for using phenolics, extracted from the lichen Cladonia verticillaris with different organic solvents, as bioherbicides have herein been studied through observation of the ultrastructural changes produced in Lactuca sativa seedlings. The different extracts mainly contain protocetraric and fumarprotocetraric acids and very small amounts of atranorin. It has been observed that the roots of lettuce seedlings grow more rapidly in the presence of the phenols than in their absence. This fact is supported by a minor number of lobes and less indentation of the parenchymatous cells as well as a major appearance of active dictyosomes in their cytoplasm. Nevertheless, seedling leaves developed in the presence of these extracts show drastic degenerative changes. Intergranal lamellae of chloroplasts disappear whereas thylakoids are melted in amorphous masses. In some cases, the number of dictyosomes increases in parenchymatous cells and mitochondria disorganize their internal membranes, though in a minor degree of that observed for chloroplasts., Ministerio de Ciencia e Innovación (España), Coordenadoira de Aperfeçioamento de Pessoal de Ensino Superior (CAPES, Brazil), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil), Depto. de Genética, Fisiología y Microbiología, Fac. de Ciencias Biológicas, TRUE, pub