Plant species of the Brazilian Caatinga experience seasonal wet and dry extremes, requiring seasonally different leaf characteristics for optimizing water availability. We investigated if Croton ...blanchetianus Baill exhibits leaf morphoanatomical traits across seasons and positioning in sunlight/natural shade. Leaves of ten 1-3 m tall plants in full sunlight and ten in natural shade were assessed in May, July (wet season), October and December (dry season) 2015 for gas exchange, leaf size, lamina and midrib cross sections (14 parameters), and chloroplast structure (5 parameters). Net photosynthesis was greater during the wet season (21.6 µm
s
) compared to the dry season (5.8 µm
s
) and was strongly correlated with almost all measured parameters (p < 0.01). Shaded leaves in the wet season had higher specific leaf area (19.9 m
kg
in full-sun and 23.1 m
kg
in shade), but in the dry season they did not differ from those in full sun (7.5 m
kg
and 7.2 m
kg
). In the wet season, the expansion of the adaxial epidermis and mesophyll lead to larger and thicker photosynthetic area of leaves. Furthermore, chloroplast thickness, length and area were also significantly larger in full sunlight (2.1 μm, 5.1 μm, 15.2 μm
; respectively) and shaded plants (2.0 μm, 5.2 μm, 14.8 μm
; respectively) during wetter months. Croton blanchetianus exhibits seasonal plasticity in leaf structure, presumably to optimize water use efficiency during seasons of water abundance and deficit. These results suggest that the species is adaptable to the increased drought stress projected by climate change scenarios.
In Brazil, the snail Biomphalaria glabrata is the most important vector of schistosomiasis due to its wide geographical distribution, high infection rate and efficient disease transmission. Among the ...methods of schistosomiasis control, the World Health Organization recommends the use of synthetic molluscicides, such as niclosamide. However, different substances of natural origin have been tested as alternatives for the control or eradication of mollusks. The literature describes the antitumor, antimicrobial and antiviral properties of usnic acid as well as other important activities of common interest between medicine and the environment. However, usnic acid has a low degree of water solubility, which can be a limiting factor for its use, especially in aquatic environments, since the organic solvents commonly used to solubilize this substance can have toxic effects on aquatic biota. Thus, the aim of the present study was to test the potassium salt of usnic acid (potassium usnate) with regard to molluscicidal activity and toxicity to brine shrimp (Artemia salina). To obtain potassium usnate, usnic acid was extracted with diethyl ether isolated and purified from the lichen Cladonia substellata. Biological assays were performed with embryos and adult snails of B. glabrata exposed for 24 h to the usnate solution solubilized in dechlorinated water at 2.5; 5 and 10 µg/ml for embryos, 0.5; 0.9; 1;5 and 10 µg/ml for mollusks and 0.5; 1; 5; 10 µg/ml for A. salina. The lowest lethal concentration for the embryos and adult snails was 10 and 1 µg/ml, respectively. No toxicity to A. salina was found. The results show that modified usnic acid has increased solubility (100%) without losing its biological activity and may be a viable alternative for the control of B. glabrata.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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.
Graphical abstract
Schematic model for demonstration of using the lichen
Cladonia verticillaris
as biomonitor of effects from gas emissions from the combustion of biodiesel blends with petroleum diesel by a stationary engine.
Display omitted
•Ramalina aspera exhibits toxicity against B. glabrata embryos and adult snails.•Quantitative and morphological changes were observed in hemocytes of B. glabrata.•Ramalina aspera ...showed lethal effects against cercariae of Schistosoma mansoni.•Ramalina aspera was non-toxic to Artemia salina at low concentrations.
In this study, the molluscicidal activities against Biomphalaria glabrata and cercaricidal activities against Schistosoma mansoni of the ether extract of Ramalina aspera were evaluated. Additionally, toxicity parameters were evaluated at sublethal doses in terms of the influence of the extract on the fertility and fecundity of snails, as well as morphological alterations and quantification of their immunological cells. A test with Artemia salina was also carried out, in order to verify the environmental toxicity of the compound. The ether extract of R. aspera, in which divaricatic acid was identified as the major compound, demonstrated molluscicidal activity at low concentrations against both embryos (LC90 of 22.78, 24.23, 16.63 and 16.03 μg mL−1 for the gastrula, blastula, trochophore and veliger, respectively) and against adult snails (LC90 of 8.66 μg mL−1), after 24 h of exposure. At the sublethal doses, it was possible to observe a decrease in fecundity and quantitative and morphological changes in the defense cells of the exposed snails. In addition, the extract of R. aspera showed a cercaricidal effect on S. mansoni from the concentration of 5.0 μg mL−1, while showing low toxicity to Artemia salina. The ether extract of R. aspera demonstrated effective molluscicidal activity on embryos and adult snails of the species B. glabrata, cercariae of S. mansoni, and presenting low toxicity on Artemia salina. In this way, it could be considered a promising compound in the development of future molluscicidal and cercaricidal agents, thus helping to combat schistosomiasis.
This study evaluated the biological activity of an ether extract and barbatic acid (BAR) from
on embryos and adult mollusks of
, cercariae of
and the microcrustacean
. The ether extract and BAR were ...obtained by successive extractions with diethyl ether. The obtained extracts were analyzed using thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), proton nuclear magnetic resonance (¹H-NMR) and infrared (IR) spectroscopy. The results demonstrated that the ether extract exerted embryotoxic effects at 50 and 100 µg/mL and molluscicidal effects at 20 and 25 µg/mL. BAR exhibited no embryotoxicity, and its molluscicidal concentration was equal to that of the ether extract. However, after 60 min of exposure, 1 µg/mL BAR presented cercaricidal activity against the parasite
at the second larval stage. Neither substance induced toxicity against
. These results indicate the potential molluscicidal activities of the ether extract and BAR against
and
cercariae. In addition to these effects, there was a lack of toxicity against the aquatic environment and no damage to the biota, indicating the potential of these products for large-scale control and/or eradication of schistosomiasis.
To obtain usnic acid potassium salt (PS-UA), the usnic acid (UA) was extracted and purified from the lichen
, and modified to produce PS-UA. The structure was determined by
H-NMR, IR and elemental ...analysis, ratified through computational models, as well as identification the site of K
insertion in the molecule. Antinociceptive activity was detected through contortions in mice induced by acetic acid and formalin (phases I and II) after treatments with 10 and 20 mg/kg of PS-UA, indicating interference in both non-inflammatory and inflammatory pain. After oral administration at doses of 500, 1000 and 2000 mg/kg, no deaths of mice with treatments below 2000 mg/kg were observed. Except for body weight gain, food and water consumption decreased with treatments of 1000 and 2000 mg/kg, and the number of segmented leukocytes was higher for both treatments. Regarding serum levels, cholesterol and triglycerides decreased, however, there was an increase in hepatic transaminases with both treatments. Liver and kidney histological changes were detected in treatments of 2000 mg/kg, while the spleen was preserved. The PS-UA demonstrated antinociceptive activity while the acute toxicity at the concentration of 2000 mg/kg was the only dose that presented morphological changes in the liver and kidney.
This study aimed to evaluate the effects of the Rn-222 progeny on the lichen
Cladonia verticillaris
under controlled conditions. The results showed resistance of the species, and few changes in the ...level of photosynthetic pigments. Blockage in the biosynthetic route of the major phenolic compound fumarprotocetraric acid was also identified, and accumulation of protocetraric acid, as defense mechanism against external pollutants, to maintain thallus vitality. The accumulation of the
210
Pb and
226
Ra, radioisotopes estimated from the daughter of
214
Bi and
214
Pb, was incipient.
C. verticillaris
showed resistance to
222
Rn, with accumulation of intermediary phenolic only at the begining of experiments.
Graphical Abstract Schematic model of exposure of
Cladonia verticillaris
(lichen) to
222
Rn under controlled conditions.
Highlights
Cladonia verticillaris
was resistant to high doses of radiation, showing stability in the production of chlorophyll.
Blockage in the biosynthesis of fumarprotocetraric acid was identified, causing accumulation of protocetraric acid, as a form of protection against the activity of Rn-222.
Daughters of Rn-222 were determined, but the species reported low accumulation, and ability of self-protection.
Abstract In the 1970s, the social impacts of protected areas (PAs) began to be widely recognized as conservationist thinking and human rights evolved to an acceptance that conservation can be ...achieved in collaboration with traditional communities. However, such a 'human face' given to conservation is still not present in some 21st century PAs: Catimbau National Park - CNP (Northeast Brazil) is a strict protection park which does not allow people residing inside its borders. Thirteen years after its creation, people are still confused about the monetary compensations and displacements strategies. In this study, a review of the bibliography concerning the CNP is performed and a proposal is made to change the current park classification from National Park to Natural Monument, allowing for private areas and their residents, providing that their use of its natural resources is compatible with the conservation objectives stipulated.
Resumen En los años 70, los impactos sociales de las áreas protegidas comenzó a ser reconocido como el pensamiento conservacionista y los derechos humanos han evolucionado a la comprensión de que la conservación se puede lograr con la colaboración de las comunidades tradicionales. Este "rostro humano" permanece ausente en algunas áreas protegidas en el siglo 21: el Parque Nacional Catimbau (PNC - noreste de Brasil), es un parque estrictamente protegido, lo que significa que la residencia de población en su límites no está permitido. Trece años después de su creación, la gente continúa confundidos acerca de la compensación monetaria y las estrategias de desplazamiento. Este estudio, realizó una revisión de la literatura en la PNC y propone cambiar la actual clasificación de Parque Nacional para Monumento Natural, lo que permite la existencia de áreas particulares asegurando que es posible conciliar los objetivos de unidad con el uso de los recursos naturales.
O manejo inadequado de técnicas de irrigação tem causado a salinização de solos da região semiárida de Pernambuco. Com base neste postulado, o objetivo principal deste estudo foi avaliar a capacidade ...do líquen Cladonia substellata, associado a uma fonte de nitrogênio ou radiação gama, como possível remediador de Neossolos Flúvicos, salinizados por irrigação não supervisionada, na ilha de Assunção, Cabrobó, Pernambuco. Coletas de líquen e solo foram realizadas para montagem de experimentos sob condições laboratoriais. Um controle de laboratório foi designado e cinco tratamentos foram desenvolvidos, por submissão à radiação gama ou fonte de nitrogênio (ureia), a diferentes concentrações, em três grupos amostrais em triplicata. Foram usadas cúpulas de vidro transparente (15) contendo amostras de solo (500 g) sobrepostas pelo talo liquênico (8 g). A cada 60 dias, por 11 meses, coletaram-se amostras das cúpulas. Foram desenvolvidas análises químicas para quantificação de fenóis produzidos pelo líquen e percolados ao solo, através de espectrofotometria e reação com FeCl.sub.3. Ao início e final dos experimentos, avaliou-se a fertilidade química dos solos dos diferentes tratamentos. Foi evidenciado que a radiação gama causou mais efeitos no líquen isoladamente, do que quando em associação com ureia. Foi constatada a hiperprodução de fenóis liquênicos, com percolação ao substrato, o que causou modificação química do solo, como o aumento dos teores de Ca, Mg, P e Na, bem como do pH. Foi possível afirmar que C substellata, associada ou não a uma fonte exógena de nitrogênio, é capaz de, a curto prazo, de alterar quimicamente solos degradados pela salinização, aumentando a biodisponibilidade de elementos essenciais às plantas e organismos do solo. Palavras-chave: Solos degradados, degradação ambiental, desertificação, ácido úsnico, substâncias liquênicas Inadequate management of irrigation techniques has caused salinization of soils in the semiarid region of Pernambuco. With this in mind, the main objective of this study was to evaluate the capacity of the lichen Cladonia substellata, associated with a nitrogen source or gamma radiation, as a possible bioremediator of Fluvic Neosols, salinized by unsupervised irrigation on Assunção Island, Cabrobó County, Pernambuco. Collections of the lichen and soil were carried out to elaborate the experiments, under laboratory conditions. A laboratory control was designed and five treatments, submitted to gamma radiation, or a nitrogen source (urea) at different concentrations, in three sampling groups, in triplicate. Fifteen, transparent glass domes were used, where soil samples (500 g) were placed and lichen thalli (8 g) superimposed. Sample collections were performed every 60 days, for 11 months. Chemical analyses for the quantification of phenolics produced by the lichen and percolated into the soil were developed through spectrophotometry and reaction with FeCl.sub.3. At the beginning and end of experiments, the chemical fertility of soils from different treatments was evaluated. It was evidenced that gamma radiation causes more effects on the lichen, singly, than in association with urea. Hyperproduction of lichen phenolics, with percolation to the substrate was achieved, which caused chemical modification of the soil, such as an increase of Ca, Mg, P and Na content, as well as pH. It is possible to affirm that C. substellata, in association or not with an exogenous nitrogen source, is capable of, in the short term, chemically altering soils degraded by salinization, increasing the bioavailability of elements essential to plants and soil organisms. Keywords: Degraded soils, environmental degradation, desertification, usnic acid, lichen substances
Usnic acid has been progressively reported in the literature as one of the most important lichen metabolites characterized by a rich diversity of applications such as antifungal, antimicrobial, ...antiprotozoal and antiviral agent. Particularly, antimicrobial activity of usnic acid can be improved by encapsulation of active molecules in enteric electrospun fibers, allowing the controlled release of active molecule at specific pH. Few relevant patents to the topic have been reviewed and cited.
Bactericidal activity of usnic acid-loaded electrospun fibers of Eudragit L-100 and polyvinylpyrrolidone was examined against Staphylococcus aureus using inhibition hales methodology.
The controlled release of active material at high pH is established after 10 minutes of interaction with media and results in reasonable activity against S. aureus, as detected by inhibition hales.
The strong biological activity of usnic acid-loaded electrospun fibers provides a promising application for corresponding material as a bactericidal agent for wound healing treatment.
PDF
