Brazilian savanna forest : conservation, medicinal reservoir and bioprospecting

This study aimed to analyse the Brazilian savanna forest from a Legal Reserve (LR) area from a perspective of conservation, reservoir of organic carbon and medicinal biomass for a prospective use of native medicinal plants. An ethnobotanical and ethnopharmacological survey was carried out close to a community settled in the rural area in the south of Tocantins, being selected 9 of the most cited species (cajuí- Anacardium othonianum; inharé-Brosimum gaudichaudii; jatobá-Hymenaeae courbaril; jenipapo-Genipa americana, aroeira-Myracrodruon urundeuva; negramina-Siparuna guianensis; barbatimão- Stryphnodendron obovatum; assa peixe-Vernonia brasiliana, embaúba-Cecropia pachystachya). Crude foliar extracts were subjected to a preliminary phytochemical prospection and triage of secondary metabolites with antimicrobial activity of potential interest in health and familiar agriculture. Phenolic compounds, terpenes and flavonoids were detected in the extracts of most species, which suggests the presence of antimicrobial, antioxidant and anti-insect activities. It was evident the need to better know the LR as a reservoir of medicinal biomass in an area under ecological tension where 35% (610ha) of the property is LR and should be protected by law. Therefore, a forest inventory of live woody species was performed using the allometric or indirect method. This identified a rare remnant of Semidecidual Seasonal Forest amidst the largest world savannah, the Cerrado biome. An analysis of the forest average productivity per basal area (m².ha), aerial live biomass (ton.ha-1) and carbon stock was carried out. The forest fragment was considered relatively rich in species and diversity, although showing signs of disturbance and dominance by a few species. Its horizontal structure suggests biotic regeneration conditions. It is an important reservoir of medicinal plants. Of the families (57.5%) presenting medicinal species, 19 from a total of 33 are represented in the area and contain 44% (27) of the total species (61) and 63% (432) of the total individuals catalogued. Medicinal species have ecological importance for the equilibrium of the local flora and represent 80% of the 10 species with higher Importance Value Index (IVI): Tetragastris altissima, Chrysophyllum marginatum, Oenocarpus distichus, Sclerolobium paniculatum, Simarouba versicolor, Alibertia macrophylla, Siparuna guianensis, Maprounea guianensis, Licania parvifolia e Physocalymma scaberrimum. Medicinal productivity was high for this type of phytophysionomy: 183,2 ton. ha-1 of biomass and 91,51 ton. ha-1 of carbon representing 66% of the total biomass and carbon of this Cerrado forest. From this stage S. guianensis (Siparunaceae) was selected for performing bioassays in order to verify its biological activity against microorganisms of health and agricultural relevance. This is a native aromatic medicinal plant recommended as priority for conservation, with local popular medicinal validation and availability of medicinal feedstock (3300 Kg.ha-1), with the foliar fraction giving 38Kg/ha of crude extract and 5L/ha of essential oil. Foliar crude extracts and essential oil were obtained and tested in vitro using a disk diffusion bioassay. Different concentrations of these natural products were tested against gram-positive bacteria (Staphylococcus aureus ATCC 29213), gram-negative bacteria (Escherichia coli ATCC 25922 and ATCC 35218; Pseudomonas aeruginosa ATCC 10145) and fungi (Candida albicans ATCC 6258 e Fusarium oxysporum). The essential oil inhibited the growth of S. aureus in its crude concentration (380μg.mL-1), as well as diluted to half (190μg.mL-1) and a quarter strength (95μg.mL-1). It’s likely that such action is due to sesquiterpenes major components, such as bisabolol and bisabolene (10.35%), measured by gas chromatography (GC-MS, GC-FID). Extracts did not exhibit any antimicrobial activity against the microorganisms tested. The native medicinal plants prospective market is an alternative that favours the conservation of biodiversity while generating benefits for the development of sustainable family productive activities within local ecosystems instead of the current inappropriate uses. This strengthens conservation policies of Legal Reserve in rural settlements and is in agreement with public policy on global warming and climate changes.

Environmental factors, clipping and fire: effects on cerrado (Brazilian savanna) native and invasive grasses

The Brazilian Cerrado houses a hugely diverse biota and is considered a conservation hotspot. One of the greatest threats to the integrity of this ecosystem is introduced African grasses, which can competitively exclude native grasses and cause changes in the microclimate and other disturbances. The Cerrado is a mosaic vegetation that provides different combinations, both spatially and temporally, of conditions that can become natural stressors to the herbaceous vegetation (water, nutrient and light availability). These mosaics are reflected in differences in relationships among native and invasive species, affecting competition and creating situations (place/season) that are more, or less, susceptible to invasion. The present study aimed to identify the different biological responses of native (Aristida recurvata, Aristida setifolia, Axonopus barbigerus, Echinolaena inflexa, Gymnopogon spicatus, Paspalum gardnerianum, Paspalum stellatum, Schizachyrium microstachyum, Schizachyrium sanguineum) and invasive (Melinis minutiflora and Andropogon gayanus) grasses to variations in natural stressors and to disturbance (fire and clipping), in order to understand changes in ecosystem functioning and competition processes between the grasses, and to understand invasion dynamics in this ecosystem. The presence of invasive species proved to affect the ecosystem functioning by increasing soil feeding activity. These differences were no longer observed in the dry season or when fires were frequent, showing that water availability and fire are more detrimental to soil feeding activity than is the vegetation. Laboratory experiments showed that both drought and flood simulated scenarios damaged both species, although the invasive species performed better under all watering conditions and responded better to fertilization. Underlying mechanisms such as the efficiency of photosynthesis and antioxidant mechanisms helped to explain this behavior. The invasive species grew faster and showed less cellular damage and a healthier photosystem, reflected in higher assimilation rates under stress. These differences between the native and invasive species were reduced with clipping, especially in dry soil with no fertilization, where the native species recovered better in relation to the pre-clipping levels. Flooding was as stressful as drought, but the invasive species can bypass this issue by growing an extensive root system, especially in the better-drained soils. Fire is more detrimental than clipping, with a slower recovery, while post-fire temperatures affect the germination of both invasive and native seeds and may be an important factor influencing the persistence of a diverse biota. This approach will finally contribute to the choice of the appropriate management techniques to preserve the Cerrado’s biodiversity.

Combined effects of chemical and natural stressors to soil organisms and plants

Nas últimas décadas, a Terra tem experimentado um aquecimento global e mudanças nos padrões de precipitação. Muitos estudos sobre a avaliação de risco de agrotóxicos em organismos não-alvo foram realizados com base em protocolos padronizados, com condições abióticas controladas. Mas, em campo, os organismos são expostos a flutuações de vários fatores ambientais, bem como a poluentes, que podem alterar os limites de tolerância dos organismos aos stressores naturais, bem como alterar a toxicidade ou biodisponibilidade do químico em causa. Considerando isso, o principal objetivo deste trabalho foi o de avaliar de que modo e em que medida os fatores ambientais (temperatura, humidade do solo e radiação UV) podem interagir uns com os outros ou afetar a toxicidade do carbaril para invertebrados do solo e plantas. Para isso, foram utilizadas quatro espécies padrão: Folsomia candida, Eisenia andrei, Triticum aestivum e Brassica rapa, e simulados diferentes cenários climáticos, com vários parâmetros letais e subletais analisados. A exposição combinada foi analisada utilizando, quando possível, a ferramenta MIXTOX, com base no modelo de referência de acção independente (IA) e possíveis desvios, assim como rácios sinergísticos/antagonísticos (a partir de valores de EC50/LC50), quando a dose-resposta de um dos stressores não foi obtida. Todos os fatores de stress aplicados isoladamente causaram efeitos significativos sobre as espécies testadas e sua exposição combinada com carbaril, apresentaram respostas diferenciadas: para as minhocas, a seca e temperaturas elevadas aumentaram os efeitos deletérios do carbaril (sinergismo), enquanto o alagamento e temperaturas baixas diminuíram sua toxicidade (antagonismo). Para os colêmbolos, o modelo IA mostrou ser uma boa ferramenta para prever a toxicidade do carbaril tanto para temperaturas altas como para as baixas. Para as duas espécies de plantas foram encontradas diferenças significativas entre elas: em termos gerais, as interações entre carbaril e os stressores naturais foram observadas, com sinergismo aparecendo como o padrão principal relacionado com a radiação UV, solos secos e temperaturas elevadas, enquanto o padrão principal relacionado com temperaturas baixas e stress de alagamento foi o antagonismo. Quando os efeitos de dois stressores naturais (radiação UV e humidade do solo) em plantas foram avaliados, uma interação significativa foi encontrada: a seca aliviou o efeito deletério da radiação UV em T. aestivum e o alagamento aumentou os seus efeitos, mas para B. rapa a adição de ambos os stresses de água causou um aumento (sinergismo) dos efeitos deletérios da radiação UV para todos os parâmetros avaliados. Portanto é necessário que as diferenças sazonais e latitudinais, bem como as mudanças climáticas globais, sejam integradas na avaliação de risco de contaminantes do solo.

Physiology and metabolic profile of Moringa olifera and Eucalyptus globulus plants subjected to climate changes

As alterações climáticas emergentes têm um grande impacto no crescimento e desenvolvimento de espécies florestais, nomeadamente em espécies de valor industrial e medicinal, como é o caso do eucalipto (Eucalyptus globulus) e da moringa (Moringa oleifera). Assim, é urgente conhecer as respostas fisiológicas e entender as variações que ocorrem nos perfis metabólicos de espécies vegetais. Neste trabalho, plantas jovens de Eucalyptus globulus foram expostas a radiação UVB (12kJ/m2) e foram avaliadas as respostas fisiológicas e o perfil metabólico, um e onze dias após a aplicação da radiação. A dose de UVB usada não afetou as reações fotoquímicas nem as trocas gasosas, contudo ao nível do metabolismo do carbono (AST e amido) e do conteúdo de pigmentos verificaram-se pequenas alterações (AST e pigmentos). Através da análise do perfil metabólico de E. globulus foram encontrados compostos voláteis e semi-voláteis pertencentes às famílias dos terpenos, sesquiterpenos e aldeídos. Em geral, os sesquiterpenos e os álcoois monoterpénicos apresentaram uma tendência para manter e, em alguns casos, diminuir com o stress, enquanto que o grupos dos aldeídos aumentou e os monoterpenos apresentaram um comportamento mais heterogéneo. O E. globulus mostrou ser uma espécie tolerante à aplicação da dose de UVB usada neste trabalho. Por outro lado, plantas jovens de M. oleifera foram expostas a défice hídrico (DH). Um grupo de plantas foi recolhido um dia após o final da exposição e o outro grupo após onze dias do final da exposição. Foi avaliado o perfil metabólico desta espécie através de GC/MS. Os dados cromatográficos indicaram que em condições de stress (DH(1) e DH(11)), as quantidades de compostos associados a vias primárias e secundárias de defesa (como os alcanos, álcoois, ácidos carboxílicos, esteróis, aminoácidos e açucares) sofreram algumas alterações. As plantas analisadas 11 dias após a remoção do stress mostraram maiores variações do perfil de metabolitos. No entanto, tanto um como onze dias após a remoção do stress, as plantas apresentaram a formação de novos rebentos. Apesar do perfil de metabolitos ter sofrido algumas alterações, por não se registarem casos de morte, conclui-se que as plantas de moringa mostraram ser tolerantes aos tratamentos aplicados.

In vitro propagation of insectivorous plants for phytochemical purposes

Dissertação mest., Engenharia Biológica, Universidade do Algarve, 2009

The role of papyrus plants (Cyperus papyrus) and internal waves in the nutrient balance of Lake Victoria, East Africa

Dissertação mest., Gestão da água e da costa, Universidade do Algarve, 2007

Phytochemical studies and biological activity of carnivorous plants from the Mediterranean region

Tese de doutoramento, Ciências Biotecnológicas (Biotecnologia Vegetal), Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2010

Root ferric chelate reductase is regulated by iron and copper in straberry plants

In the present experiment, we studied the interaction between copper (Cu) and iron (Fe) in strawberry plants grown in nutrient solutions containing different concentrations of Fe. Plants grown in the absence of iron (Fe0) had the characteristic symptoms of Fe deficiency, with smaller chlorotic leaves, less biomass, acidification of the nutrient solution, and roots that were smaller and less ramified, while no symptoms of Fe deficiency were observed in plants grown with Fe. A greater amount of Cu was found in roots of chlorotic plants than in those grown with Fe, while plants grown with 20M of Fe (Fe20) in the nutrient solution had a greater amount of Fe compared with plants from the other treatments. Chlorotic plants (Fe0) and plants grown with the greatest level of Fe (Fe20) had a greater root ferric chelate reductase (FC-R; EC 1.16.1.17) activity compared with the other treatments with 5 or 10M Fe in the nutrient solution. The same pattern was obtained for relative FC-R mRNA concentration and for the sum of Fe and Cu contents in shoots (leaves plus crowns). The DNA obtained from amplification of the FC-R mRNA was cloned and several of the inserts analysed by single strand confirmation polymorphism (SSCP). Although there were different SSCP patterns in the Fe20 treatment, all the inserts that were sequenced were very similar, excluding the hypothesis of more than one FC-R mRNA species being present. The results suggest that Cu as well as Fe is involved in FC-R expression and activity, although the mechanism involved in this regulation is unknown so far. Both small contents of Fe and Cu in plants led to an over-expression of the FC-R gene and enhanced FC-R activity in strawberry roots.

Aromatic plants, spices and volatiles in food and beverages

The use of spices, common nowadays, was once a sign of high position, luxury and wealth. The value of food ingredients is thus determined by the time in which one lives, that is, it is a product of fashion, since they are always used in a social context. Many plants used as spices enjoyed fame and undeniable importance in the past but their reign was more or less ephemeral, as they were rejected in favour of others for food seasoning, or simply upstaged and/or used for other purposes.

Metal cycling in salt marshes and intertidal mudflats : influence of plants, invertebrates and fishes

Tese de doutoramento, Biologia (Ecologia), Universidade de Lisboa, Faculdade de Ciências, 2015

Animism in Rainforest and Tundra: Personhood, Animals, Plants and Things in Contemporary Amazonia and Siberia (Book Review)

Animism is a form of traditional spiritual belief that receives welcome treatment here. The observations of Victorian ethnologist travellers on the local peoples they regarded as primitive was analysed by Sir Edward (E. B.) Tylor, in Primitive Culture (1871) which established the working definition of animism followed by later generations of scholars. This came from the observation that non-scientific people did not always draw sharp distinctions between human persons and other entities such as animals, trees and even rocks but imbued these with soul. The latin anima, ‘soul, spirit’ provided the title of what was assumed to be a primitive religion, animism. The study being reviewed recognizes apparent connections within deep history between Siberia and the Amazon, and uses contemporary social anthropology to clarify assumptions about animism. This book on animism in two shamanic cultures explores personhood and the relations in pre-scientific human thought between humans and non-humans, in contexts where non-humans can be regarded as social persons (p.2).

A thin-layer chromatography-bioautographic method for detecting dipeptidyl peptidase IV inhibitors in plants

A thin-layer chromatography (TLC)-bioautographic method was developed with the aim to detect dipeptidyl peptidase IV (DPP IV) inhibitors from plant extracts. The basic principle of the method is that the enzyme (DPP IV) hydrolyzes substrate (Gly-Pro-p-nitroaniline) into p-nitroaniline (pNA), which diazotizes with sodium nitrite, and then reacts with N-(1-naphthyl) ethylenediamine dihydrochloride in turn to form a rose-red azo dye which provides a rose-red background on the TLC plates. The DPP IV inhibitors showed white spots on the background as they blocked enzymolysis of the substrate to produce pNA. The method was validated with respect to selectivity, sensitivity, linearity, precision, recovery, and stability after optimizing key parameters including plate type, time and temperature of incubation, concentration of substrate, enzyme and derivatization reagents, and absorption wavelength. The results showed good lineary within amounts over 0.01–0.1 μg range for the positive control, diprotin A, with the coefficient of determination (r2) = 0.9668. The limits of detection (LOD) and quantification (LOQ) were 5 and 10 ng, respectively. The recoveries ranged from 98.9% to 107.5%. The averages of the intra- and inter-plate reproducibility were in the range of 4.1–9.7% and 7.6–14.7%, respectively. Among the nine methanolic extracts of medicinal herbs screened for DPP IV inhibitors by the newly developed method, Peganum nigellastrum Bunge was found to have one white active spot, which was then isolated and identified as harmine. By spectrophotometric method, harmine hydrochloride was found to have DPP-IV inhibitory activity of 32.4% at 10 mM comparing to that of 54.8% at 50 μM for diprotin A.

Electromagnetic transients analysis of lightning overvoltages on wind power plants

As wind power generation undergoes rapid growth, lightning and overvoltage incidents involving wind power plants have come to be regarded as a serious problem. Firstly, lightning location systems are discussed, as well as important parameters regarding lightning protection. Also, this paper presents a case study, based on a wind turbine with an interconnecting transformer, for the study of adequate lightning and overvoltage protection measures. The electromagnetic transients circuit under study is described, and computational results are presented.