1,264 research outputs found
Antioxidant,antimicrobial and toxicological properties of Schinus molle L. essential oils
Ethnopharmacological relevance: Schinus molle L. has been used in folk medicine as antibacterial, antiviral, topical antiseptic, antifungal, antioxidant, anti-inflammatory, anti-tumoural as well as antispasmodic and analgesic; however, there are few studies of pharmacological and toxicological properties of S. molle essential oils.
Aim of the study: The aim of this study was to evaluate the antioxidant and antimicrobial activities of S. molle leaf and fruit essential oils, correlated with their chemical composition and evaluate their acute toxicity.
Materials and methods: The chemical composition of S. molle leaf and fruit essential oils were evaluated by GC-FID and GC-MS. Antioxidant properties were determined using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical and β-carotene/linoleic acid methods. Antimicrobial properties were evaluated by the agar disc diffusion method and minimal inhibitory concentration assay. Toxicity in Artemia salina and acute toxicity with behavioural screening in mice were evaluated.
Results: The dominant compounds found in leaf and fruit essential oils (EOs) were monoterpene hydrocarbons, namely -phellandrene, β-phellandrene, β-myrcene, limonene and α-pinene. EOs showed low scavenging antioxidant activity by the DPPH free radical method and a higher activity by the β-carotene/linoleic acid method. Antimicrobial activity of EOs was observed for Gram+, Gram– pathogenic bacteria and food spoilage fungi. EOs showed cytotoxicity for Artemia salina and lower toxicity in Swiss mice.
Conclusions: The result showed that EOs of leaves and fruits of S. molle demonstrated antioxidant and antimicrobial properties, suggesting their potential use in food or pharmaceutical industries
Micropropagation of a recalcitrant pine (Pinus pinea L.): An overview of the effects of ectomycorrhizal inoculation
Stone pine (Pinus pinea L.) is an economically important forest species in some regions of Iberian Peninsula. Portugal and Spain have nearly 500,000 ha of stone pine stands, representing 85% of worldwide distribution. The main use of this species is for the production of seeds (pinion) for food industry. In addition to its enormous profitability as a producer of seeds, it has beneficial impact on soil protection, dunes fixation and is a pioneer species particularly for cork and holm oaks degraded ecosystems. Stone pine plantations are today a major source of income for forestry holdings. Investments have targeted breeding, reforestation, forest management and harvesting. The maternal inheritance of desirable characteristics such as cone weight, number of seeds per cone and seed length is considerably high in this species thus encouraging the selection of seeds from “plus” trees. The selected trees have been propagated by grafting and micropropagation. However, grafting generates high variability due to scion-rootstock interaction that varies production levels. The production of clonal plants from selected seeds by micropropagation techniques has advanced very slowly due to the recalcitrance of this species in tissue culture and particularly to adventitious rooting of microshoots. Due to the tremendous importance of developing a reproducible tissue culture method for clonal propagation, a study has been carried out for over a decade to enhance rooting and acclimation. During this period of time, continuous increments in the multiplication rate and rooting frequency were achieved by introducing variations in culture media composition and conditions. Auxins, carbohydrates, light quality and duration, temperature at different concentrations and levels as well as compounds such as coumarin; salicylic acid, polyamines, etc. were tested for induction and expression phases of adventitious rooting. Despite these efforts, microshoots regenerated through organogenesis from mature embryo cotyledons failed to root or to have sustained root growth. At this point, an in vitro co-culture technique of stone pine microshoots with ectomycorrhizal-fungi was introduced to overcome the adventitious root growth cessation in vitro and improve root development during acclimation phase. An overview of the results showing the positive effect of fungal inoculation in promoting root growth in vitro and on plantlet survival during acclimation will be presented. Preliminary results of biochemical signals between Pinus pinea/Pisolithus arhizus during early steps of in vitro culture detected by liquid chromatography-mass spectrometry that might be responsible for the positive effect on root growth will be also presented
The role of acetylcholinesterase in Alzheimer’s disease: Enzymatic inhibition studies
Alzheimer’s disease (AD) is the most common form of dementia and causes a progressive and irreversible neurodegeneration. It is related
with loss of cholinergic function, which affects memory, learning and behavior [1]. Neurophathologically, AD is characterized by the presence
of beta-amyloid plaques (A ) and neurofibrillary tangles (NFT) [2] and consequent degeneration of the basal forebrain cholinergic neurons
[3]. The loss of cholinergic neurons leads to the progressive reduction of acetylcholine (ACh) in the brain and resulting cognitive impairment
in AD [3]. As such, the enzyme acetylcholinesterase (AChE) has been one of the prime targets in search for a treatment for AD, which uses
reversible inhibitors of AChE, in order to increase levels of acetylcholine (ACh) in the brain [4].
In the present study a small library of quinolinone and indole derivatives was screened for their eeAChE inhibitory activity using the Ellman
method
Differentially expressed genes involved in lipid metabolism in the muscle tissue of Alentejano and Bísaro pig breeds
The Alentejano (AL) and Bísaro (BI) pigs stand as the predominant local breeds raised in Portugal. AL pigs are characterized by lower growth rates and precocious and higher lipid deposition, particularly of monounsaturated fatty acids, when compared to BI pigs. Lipid and fatty acids composition of meat and meat products are important features for consumers health, and gene expression is a decisive process determining fatty acid composition and deposition rates in the muscle tissue of every mammal. This study investigates the transcriptomic fundamentals associated to the phenotypical differences through a real-time qPCR approach on a set of candidate genes responsible for regulating lipid metabolism processes. Longissimus lumborum samples were collected at slaughter from five animals of each breed raised under similar conditions until ~150kg BW. Total RNA was extracted, and target cDNA was amplified to estimate expression levels when compared to endogenous control genes. Several lipogenic related genes were found to be overexpressed in the AL breed including ACLY (log2FC=0.50, p<0.05), ELOVL6 (log2FC=0.67, p<0.01), ME1 (log2FC=0.78, p<0.05), while other major lipogenic markers, such as FASN (log2FC=0.45, p=0.09) and ACACA (log2FC=0.28, p=0.17) did not attain statistical significancy, but indicate a tendency towards AL. The gene coding for the central appetite regulation hormone (LEP) was detected as significantly overexpressed in AL (log2FC=1.60, p<0.05), which may suggest the occurrence of leptin resistance in this breed, comparable to what happens with the genetically similar Iberian pig, failing to decrease feeding and increase stored energy expenditure. Similarly, adiponectin resistance is predicted to have developed in AL pigs since higher ADIPOQ levels (log2FC=0.90, p<0.01) are associated with leaner animals due to the activation of fatty acid oxidation pathways by this regulator. These results agree with the previously described high intramuscular fat content profile of the AL breed, essential in enhancing the overall sensory quality of its meat and meat products
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Bilingualism Is Associated with a Delayed Onset of Dementia but Not with a Lower Risk of Developing it: a Systematic Review with Meta-Analyses.
Some studies have linked bilingualism with a later onset of dementia, Alzheimer's disease (AD), and mild cognitive impairment (MCI). Not all studies have observed such relationships, however. Differences in study outcomes may be due to methodological limitations and the presence of confounding factors within studies such as immigration status and level of education. We conducted the first systematic review with meta-analysis combining cross-sectional studies to explore if bilingualism might delay symptom onset and diagnosis of dementia, AD, and MCI. Primary outcomes included the age of symptom onset, the age at diagnosis of MCI or dementia, and the risk of developing MCI or dementia. A secondary outcome included the degree of disease severity at dementia diagnosis. There was no difference in the age of MCI diagnosis between monolinguals and bilinguals [mean difference: 3.2; 95% confidence intervals (CI): -3.4, 9.7]. Bilinguals vs. monolinguals reported experiencing AD symptoms 4.7 years (95% CI: 3.3, 6.1) later. Bilinguals vs. monolinguals were diagnosed with dementia 3.3 years (95% CI: 1.7, 4.9) later. Here, 95% prediction intervals showed a large dispersion of effect sizes (-1.9 to 8.5). We investigated this dispersion with a subgroup meta-analysis comparing studies that had recruited participants with dementia to studies that had recruited participants with AD on the age of dementia and AD diagnosis between mono- and bilinguals. Results showed that bilinguals vs. monolinguals were 1.9 years (95% CI: -0.9, 4.7) and 4.2 (95% CI: 2.0, 6.4) older than monolinguals at the time of dementia and AD diagnosis, respectively. The mean difference between the two subgroups was not significant. There was no significant risk reduction (odds ratio: 0.89; 95% CI: 0.68-1.16) in developing dementia among bilinguals vs. monolinguals. Also, there was no significant difference (Hedges' g = 0.05; 95% CI: -0.13, 0.24) in disease severity at dementia diagnosis between bilinguals and monolinguals, despite bilinguals being significantly older. The majority of studies had adjusted for level of education suggesting that education might not have played a role in the observed delay in dementia among bilinguals vs. monolinguals. Although findings indicated that bilingualism was on average related to a delayed onset of dementia, the magnitude of this relationship varied across different settings. This variation may be due to unexplained heterogeneity and different sources of bias in the included studies. Registration: PROSPERO CRD42015019100
Eléctrodo de terra em serpentina
Este artigo tem como principal objectivo a divulgação de uma aplicação informática para calcular a resistência de difusão de eléctrodos de terra em serpentina, a qual é representada analiticamente por uma sinusóide.
No cálculo da resistência utilizou-se o chamado método da matriz, desenvolvido por S. Meliopoulos. Como a distribuição de potencial no solo obedece à equação de Laplace, o eléctrodo de terra é previamente discretizado em pontos-fonte de corrente eléctrica, situados no eixo dos condutores. O modelo discreto é representável por um sistema de equações lineares que permite calcular as correntes dos pontos-fonte, arbitrando uma tensão no eléctrodo. A corrente deste é a soma das correntes pontuais, e a lei de Ohm permite calcular facilmente a resistência de terra. Os resultados permitem observar que a resistência da serpentina diminui com o aumento do número de máximos, com o aumento da profundidade de enterramento e com o aumento da largura da vala. Conclui-se da utilidade da serpentina, comparada com o simples cabo horizontal, já que possui resistência de terra menor
Differential role of entorhinal and hippocampal nerve growth factor in short- and long-term memory modulation
Afghanistan - Primitive wellColorVolume 33, Page
UV Spectroscopy of Metal-Poor Massive Stars in the Small Magellanic Cloud
The Hubble Space Telescope has provided the first clear evidence for weaker
winds of metal-poor massive stars in the Small Magellanic Cloud, confirming
theoretical predictions of the metallicity dependence of mass-loss rates and
wind terminal velocities. For lower luminosity O-type stars however, derived
mass-loss rates are orders of magnitude lower than predicted, and are at
present unexplained.Comment: 4 pages, 3 figures. To appear in 'The Impact of HST on European
Astronomy', Eds., G. De Marchi & F.D. Macchetto, Astrophysics & Space
Science, Springe
In vitro cultivation of Brosimum gaudichaudii Tréc. (Moraceae)
O objetivo desta pesquisa foi avaliar o potencial organogenético de entrenós, discos foliares, e raízes de Brosimum gaudichaudii utilizando 12 diferentes combinações dos fitorreguladores 6-benzilaminopurina e ácido naftaleno acético, em meio MS (diluído à metade), sólido (6,5 g de ágar), e com 20 g.L-1 de sacarose. Independentemente das combinações hormonais testadas verificou-se a formação de calos friáveis (2 a 20 mm de diâmetro) em 90% dos entrenós usados como explantes. No entanto, os tratamentos testados não foram capazes induzir calos ou gemas em raízes e em discos foliares. O estudo anatômico revelou a formação de meristemóides nas regiões mais externa e mais interna dos calos. Os resultados obtidos poderão servir de base para novos testes de indução de calos na espécie.The objective of this research was to evaluate the organogenic potential of internodes, leaf discs and roots of Brosimum gaudichaudii using 12 different combinations of the plant growth regulators 6-benzylaminopurine and naphthalene acetic acid in MS medium (half strength), solid medium (6.5 g agar) and sucrose medium (20 g.L-1). Regardless the hormonal combination tested, we observed the formation of friable calluses (2 - 20 mm wide) in 90% of the internode explants. However, the treatments were not able to induce callus or buds on roots and leaf discs. The anatomical analysis revealed meristemoid formation in the outer and inner regions of the calluses. The results may serve as the basis for further testing of callus induction in this species
Sr-Nd isotope signatures of surficial sediments from the Portuguese continental shelf
This study focus on the Sr-Nd isotope signatures of detrital and carbonate fractions of seven samples from surficial sediments deposited in the Portuguese continental shelf. 87Sr/86Sr and 143Nd/144Nd isotope compositions of the lithic component are used to constrain potential endmember contributions and determine sediment provenance. The 87Sr/86Sr ratios measured in the acid leachates of the seven sediment samples (carbonate fraction) lie within the range 0.7088 – 0.7092, close to the value for modern seawater (0.7091 – 0.7092), suggesting a dominant biogenic origin for this component. In contrast, the Sr isotope signatures for acid-leached silicate residues (lithic fraction) from the same samples are widely variable (87Sr/86Sr = 0.7179 to 0.7346) reflecting the input of terrigenous particles from three distinct sources (northern Iberian Variscan crust, southern Iberian Variscan crust and North African aerosols). The narrow range of ƐNd(0) values displayed by these samples (-8.5 to -10.6) does not allow effective discrimination between the different endmembers
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