Synthesis of sugar-biguanide hybrids to study their potential biological effects

Synthesis of sugar-biguanide hybrids was attempted by starting the approach from dicyanamide salts, by use of acidic medium to activate the dicyanamide for amine addition to create a biguanide compound to be connected to a sugar by a triazole ring. Green Chemistry principles were considered to try and maintain the reaction as “green” as possible and that was partially achieved in the biguanide synthesis pathway. NMR was the primary tool for monitoring the success of the reactions. The reactions with the sugars were already known in literature, Galactose and Mannose derivatives were obtained, dimethyl, β-naphtyl and imidazole cyanoguanidine were obtained as well, the yields obtained varied, between 20-60%. The carbon NMRs allowed for a fast way to know if the guanidine reactions happened, with the appearance of a signal around 160 ppm, this facilitates identification and doesn’t waste as much resources.A síntese de híbridos açúcar-biguanida foi tentada começando a abordagem a partir de sais de dicianamida, pelo uso de meio ácido para ativar a dicianamida adicionando a amina para criar um composto de biguanida, a ser conectado a um açúcar por um anel triazole. Os princípios da Química Verde foram considerados para tentar manter a reação o mais “verde” possível e isso foi parcialmente alcançado na via de síntese da biguanida. RMN foi a principal ferramenta para monitorar o sucesso das reações. As reações com os açúcares já eram conhecidas na literatura, foram obtidos derivados de Galactose e Manose, foram obtidos também dimetil, β-naftil e imidazol cianoguanidinas, os rendimentos obtidos variaram, entre 20-60%. Os RMNs de carbono possibilitaram uma maneira rápida de saber se ocorreram as reações de guanidina, com o aparecimento de um sinal em torno de 160 ppm, o que facilita a identificação e não desperdiça tantos recursos

Responses to water stress in two Eucalyptus globulus clones differing in drought tolerance

We evaluated drought resistance mechanisms in a drought-tolerant clone (CN5) and a drought-sensitive clone (ST51) of Eucalyptus globulus Labill. based on the responses to drought of some physiological, biophysical and morphological characteristics of container-grown plants, with particular emphasis on root growth and hydraulic properties. Water loss in excess of that supplied to the containers led to a general decrease in growth and significant reductions in leaf area ratio, specific leaf area and leaf-to-root area ratio. Root hydraulic conductance and leaf-specific hydraulic conductance decreased aswater stress became more severe. During the experiment, the drought-resistant CN5 clone maintained higher leaf water status (higher predawn and midday leaf water potentials), sustained a higher growth rate (new leaf area expansion and root growth) and displayed greater carbon allocation to the root system and lower leaf-to-root area ratio than the droughtsensitive ST51 clone. Clone CN5 possessed higher stomatal conductances at moderate stress as well as higher hydraulic conductances than Clone ST51. Differences in the response to drought in root biomass, coupled with changes in hydraulic properties, accounted for the clonal differences in drought tolerance, allowing Clone CN5 to balance transpiration andwater absorption during drought treatment and thereby prolong the period of active carbon assimilation

Geographic variation in cork oak and its implications for expected impacts of climate change

Cork oak (Quercus suber L.) is a protected tree species in Portugal, being also the source of raw material for the cork industry, a major player in Portuguese economy (representing 3% of GDP in 2010). The future climatic scenarios for Portugal point to an increase in average summer temperatures from 0.3 to 0.7ºC between 2016 and 2035, and up to 4.6ºC until 2100. In addition, precipitation estimates suggest a reduction of annual rainfall from 20 to 40%, especially in southern Portugal. Water stress will, therefore, be a leading constraint to primary production. The combined effects of drought and high temperatures will lead to decreases in carbon assimilation and increases in tree mortality, and consequently current reforestation efforts will need to account for these expected adverse outcomes through the sustainable use of suitable genetic material. There are several reasons that can be highlighted to emphasize the need for an efficient management of cork oak genetic resources in Portugal, namely: i) to avoid cork import, and thus to increase cork production to meet the industry demands; ii) to overcome a generally poor area of natural regeneration, which does not help to ensure an in situ conservation of genetic resources; iii) to deploy adapted genetic material for afforestation/reforestation; and iv) to develop a gene resources conservation program, as cork oak is a vital component of agro-silvopastoral systems in the Mediterranean region. Given the broad native range of the species, involving significant environmental and geographic gradients, a high level of genetic variation can be expected. It is possible that disruptive selection has caused a large differentiation in adaptive traits among populations, namely in the ability to tolerate different environmental stress events (e.g. drought and frost) and to cope with pests and diseases. Between 1998 and 2011, we have collected data involving survival, growth, phenology and water-use efficiency traits from five common-garden provenance trials (including family structure in two of the trials), that were established in Portugal under a concerted action launched by the EUFORGEN’s network. These multi-site field experiments are based on up to 35 tested provenances covering the entire natural distribution of cork oak, and results obtained from the genetic evaluation of the trials have indicated significant differences among populations for all the measured traits at all observed ages. Four of the tested provenances (Alpujarras – Haza de Lino, Puglia – Lucci - S. Teresa, Landes - Soustons, Rif Occidental – Ain Rami) were then chosen according to their contrasting field performance for growth, phenology and water-use efficiency (WUE), and were further evaluated under controlled-environment conditions where drought stress was induced. In this context, the main drivers of drought adaptation appeared to be early stomatal closure and root investment, which also showed significant differences among the selected provenances. The responses to drought over time also varied among these studied populations, and seemed to be related to their differences in growth rhythm. The Ain Rami population seemed to be most prone population to endure drought conditions. Facing a water deficit scenario this population, with highest growth, showed a higher investment on roots compared to the Haza de Lino population, that even under optimal hydration status, had lower biomass values, more reduced transpiration area (smallest size, with lowest Specific Leaf Area), leading to a lower water consumption. This population showed a delay in onset of stress when compared to other populations, only revealed no stomatal limitations with high stress levels. Furthermore, Ain Rami showed higher WUE under drought conditions both in the field trials and under controlled conditions, but average WUE in wet conditions. The results from the field and controlled-environment experiments were consistent in that geographic origin had an important influence on the performance of fitness surrogates and functional traits, and thus providing a strong indication that seed origin must be considered in cork oak reforestation programs.info:eu-repo/semantics/publishedVersio

Efeito da idade e da fertilização na qualidade das plantas de sobreiro (Quercus suber L.) em viveiro

Congresso Florestal Nacional: a floresta e as gentes - Actas das ComunicaçõesA plantação tem sido uma técnica muito utilizada em projectos de reflorestação do montado de sobro, uma vez que a sementeira é limitada temporalmente pelo facto de não se dominar a conservação a longo prazo das glandes (sementes recalcitrantes). Consequentemente, a produção das plantas provém exclusivamente de sementes frescas (Novembro - Janeiro) condicionando a sua idade no momento da plantação (10-14 meses). A idade da planta influencia o seu potencial de crescimento após a plantação, estando regulamentada por legislação (Decreto-Lei nº 205/2000, de 12 de Setembro). A aplicação de fertilizantes tem sido sugerida como uma técnica de produção em viveiro destinada a melhorar a qualidade da planta. No âmbito de diversos projectos (CREOAK-QLK5-CT-2002-01594; POCTI/41359/AGG/2001), temos vindo a aprofundar o conhecimento sobre a qualidade das plantas do sobreiro. Produziram-se em viveiro, plantas de idade diferente provenientes de sementes frescas e conservadas (3 e 6 meses), obtendo-se respectivamente plantas de 9, 7 e 5 meses. Nas plantas de 7 meses, foi aplicado um tratamento de fertilização (50 ml da solução NPK, 12-2-12) e de micorrização (Pisolithus tinctorius). Foram avaliados diferentes parâmetros morfológicos e fisiológicos durante a fase de crescimento da planta em viveiro, assim como o potencial de crescimento das raízes no momento de plantação. Os resultados apresentados centram-se no efeito de ambos os factores (idade à plantação e fertilização) na qualidade das plantas

Effects of an extremely dry winter on net ecosystem carbon exchange and tree phenology at cork oak woodland

In seasonally dry climates, such as the Mediterranean, lack of rainfall in the usually wet winter may originate severe droughts which are a main cause of inter-annual variation in carbon sequestration. Leaf phenology variability may alter the seasonal pattern of photosynthetic uptake, which in turn is determined by leaf gas exchange limitations. The current study is based on the monitoring of an extremely dry winter in an evergreen cork oak woodland under the Mediterranean climate of central Portugal. Results are focused on net ecosystem CO2 exchange (NEE), phenology and tree growth measurements during two contrasting years: 2011, a wet year with a typical summer drought pattern and 2012, with an extremely unusual dry winter (only 10mmof total rainfall) that exacerbated the following summer drought effects. Main aims of this study were to assess the effects of an extreme dry winter in (1) annual and seasonal net ecosystem CO2 exchange, and in (2) cork oak phenology. The dry year 2012 was marked by a 45% lower carbon sequestration (−214 vs. −388gCm−2 year−1) and a 63% lower annual tree diameter growth but only a 9% lower leaf area index compared to the wet year 2011. A significant reduction of 15% in yearly carbon sequestration was associated with leaf phenological events of canopy renewal in the early spring. In contrast to male flower production, fruit setting was severely depressed by water stress with a 54% decrease during the dry year. Our results suggest that leaf growth and leaf area maintenance are resilient ecophysiological processes under winter drought and are a priority carbon sink for photoassimilates in contrast to tree diameter growth. Thus, carbon sequestration reductions under low water availabilities in cork oak woodland should be ascribed to stomatal regulation or photosynthetic limitations and to a lesser extent to leaf area reductionsinfo:eu-repo/semantics/publishedVersio

Bases fisiológicas para a distribuição de clones de Eucalyptus globulus Labill. por diferentes áreas edafo-climáticas

Congresso Florestal Nacional: a floresta e as gentes - Actas das ComunicaçõesO Eucalyptus globulus Labill., pela sua importância económica, encontra-se distribuído por todos os países de clima favorável, reflectindo o interesse que têm as suas características intrínsecas como sejam um rápido crescimento e uma superior qualidade da madeira para produção de pasta para papel. Em Portugal, a relevância económica desta espécie traduz-se quer em termos de uma contribuição positiva para a balança comercial quer em termos do investimento feito na plantação de novas áreas florestais. No entanto, devido à restrição ao aumento da área de plantações verifica-se uma crescente exigência em aumentar a produtividade das áreas plantadas, garantindo a sustentabilidade económica, social e ambiental dos ecossistemas florestais. Actualmente, a área clonal de E. globulus é de aproximadamente 15000 ha tendo vindo a aumentar nos últimos anos cerca de 2000 ha por ano, como resultado das melhores técnicas de propagação e dos programas de melhoramento. Uma vez que o nº de clones comercialmente interessantes para a produção e que são utilizados em plantações tem tendência a ser reduzido, torna-se necessário deter um conhecimento mais aprofundado das suas respostas fisiológicas de forma a reduzir o risco inerente a uma diminuição da diversidade genética. Particularmente, e porque em Portugal as plantações ocorrem em áreas onde ocorrem défices hídricos sazonais, havendo uma grande variabilidade interanual no stress hídrico e sendo previsível um agravamento da aridez num futuro próximo, é necessário conhecer detalhadamente os mecanismos de resistência ao stress hídrico de forma a sustentar as decisões de distribuição dos clones por diferentes regiões edafo-climáticas. Este trabalho constitui um primeiro passo para o aprofundamento do conhecimento dos processos fisiológicos, de modo a identificar características biológicas que sirvam de referência à selecção de genótipos, permitindo uma consolidação dos resultados obtidos nos ensaios de campo e, portanto, uma mais ajustada distribuição dos clones pelos seus locais de plantação e crescimento futuro. Especificamente, avaliaram-se em condições controladas os mecanismos de resistência à secura em dois clones de Eucalyptus globulus Labill. com diferente sensibilidade à secura no campo, com base em estudos fisiológicos, biofísicos e morfológicos

Metabolic responses to water deficit in two Eucalyptus globulus clones with contrasting drought sensitivity

We compared the metabolic responses of leaves and roots of two Eucalyptus globulus Labill. clones differing in drought sensitivity to a slowly imposed water deficit. Responses measured included changes in concentrations of soluble and insoluble sugars, proline, total protein and several antioxidant enzymes. In addition to the general decrease in growth caused by water deficit, we observed a decrease in osmotic potential when drought stress became severe. In both clones, the decrease was greater in roots than in leaves, consistent with the observed increases in concentrations of soluble sugars and proline in these organs. In roots of both clones, glutathione reductase activity increased significantly in response towater deficit, suggesting that this enzyme plays a protective role in roots during drought stress by catalyzing the catabolism of reactive oxygen species. Clone CN5 has stress avoidance mechanisms that account for its lower sensitivity to drought compared with Clone ST51

Polineuropatia periférica por Hanseníase: Peripheral polyneuropathy due to Leprosy

A hanseníase é uma doença infecciosa, transmitida principalmente pelas vias aéreas, possuindo agente etiológico Mycobacterium leprae, um bacilo tipo BAAR. É uma doença inicialmente assintomática, de evolução crônica e suas manifestações patognomônicas são dermatoneurológicas, sendo uma das suas principais complicações a polineuropatia periférica por hanseníase, a qual é o foco do nosso trabalho. Trata-se de uma revisão sistemática por intervenção de pesquisas bibliográficas que ocorreu por meio de buscas nas bases de dados Google Acadêmico, PubMed e Scielo – cujos descritores são “Hanseníase”, “Neuropatia” e “Complicações neurológicas”. A polineuropatia periférica por hanseníase é uma complicação de mau prognóstico, baixa qualidade de vida e gera muitas incapacidades no paciente. Portanto, visa-se tornar mais rápido o diagnóstico e tratamento dessa patologia, de modo a prevenir essa complicação grave nos pacientes infectados pelo bacilo