Propolis components accountable for bactericidal accomplishment and antibiofilm activity

This study aimed at evaluating antimicrobial and antibiofilm activity of phenolic compounds present in propolis ethanol extracts (PEE). Seventy per cent ethanol extracts from seven types of propolis, one Green, two Red and four Brown collected in four Brazilian States were prepared and total phenolics, flavonoids, tannins and anthocyanins were assessed by high-performance liquid chromatography (HPLC). Minimum bactericidal concentration (MBC) and inhibitor effect on Staphylococcus aureus biofilm formation and capacity to disrupt established biofilms were assessed towards eight S. aureus isolates from milk of small ruminants with mastitis, one methicillin-resistant S. aureus (MRSA) and S. aureus ATCC 25923. To evaluate different propolis components accountability for bactericidal accomplishment and antibiofilm activity, the results were analysed by the non-parametric Spearman coefficient. Results of phenolic compounds were 216,21 to 312,08 gallic acid milligram equivalent per extract gram (mg EGA/g) of total phenolics, 55,08 to 140,6 quercetin milligram equivalent per extract gram (mg EQ/g) of flavonoids, 118,51 to 3766,16 catechin milligram equivalent per extract gram (mg EC/g) of tannins and 1,03 to 8,39 milligram per extract gram (mg/g) of anthocyanins. Red1 and Red2 showed higher tannin contents, while Red2 exhibited superior amount of anthocyanins and total phenolics. Brown3 presented higher flavonoid quantity. Green, Red1 and Red2 PEE showed the lowest levels of flavonoids, but the higher antimicrobial activity. Most PEE exhibit bactericidal activity at a concentration of 1.6 mg/mL. Brown4 PEE showed the worst capacity to inhibit S. aureus. Green PEE showed to be the most efficient in both preventing and disrupting biofilm. All PEE studied exhibited a better inhibitory activity prior-to than post-biofilm formation. According to non-parametric Spearman correlation analysis, there seems to be a significant negative correlation between the ability to disrupt biofilm and both tannins and anthocyanins contents.

Effects of nitrogen level on purslane antioxidant activity.

The high antioxidant activity of purslane, Portulaca oleracea L., gives it a high nutritional and functional value. The commercial production of purslane has increased in Portugal, making it necessary to know the effects of inputs, mainly nitrogen, on the antioxidant activity. The main goal of this study was to evaluate the influence of nitrogen application on purslane antioxidant activity. The experiment was carried out with for treatments: 30, 60 and 90 kg/ha of nitrogen. Plants of golden-leaf purslane were grown in Styrofoam-boxes filled with substrate and fertigated two times per week, over four weeks with ammonium nitrate solution (16.9% NO3-N and 16.7 NH4+-N). The increase in the nitrogen level decreased the water-soluble proteins content. However the ascorbate, phenols content as well as antioxidant activity measured by FRAP method was not affected by nitrogen level. Plants shoot antioxidant activity, measured by DPPH method decreased significantly in the treatment with 90 kg N/ha (26.20 g/g gallic acid). On the other hand, plant shoot antioxidant activity mediated by peroxidases was higher in treatment 30 kg N/ha (0.459 µmol min-1/mg prot.). Application of 60 kg N/ha allowed a vigorous plant growth without disturb its antioxidants and conservation properties.

The Branches of Large Electricity Companies in Portugal: From Trade to the Transfer and Adaptation of Technology (20th Century)

In the last decade of the 19th and first decades of the 20th century there was a movement of capital and engineers from the central and northern Europe to the countries of southern Europe and other continents. Large companies sought to obtain concessions and establish branches in Portugal, favouring the circulation of technical knowledge and transfer of technology for Portuguese industry. Among the various examples of the representatives of foreign companies in Portugal we find Jayme da Costa Ltd. established in 1916 in Lisbon, which was a branch of the Swedish company ASEA, as well as STAAL, ATLAS DIESEL (Sweden), Landis & GYR (Switzerland), Electro Helios, etc.. Another example is EFACEC a company founded in 1948 in Porto, that was a partnership between the Portuguese company CUF – Companhia União Fabril, and ACEC – Ateliers de Constructions Électriques de Charleroi and a small entreprise Electro-Moderna Ldª. This enterprise started the industrial production of electric motors and transformers, and later on acquired a substantial share of the national production of electrical equipment. Using Estatística das Instalações Elétricas em Portugal (Statistics on Electrical Installations in Portugal) from 1928 until 1950 we can identify the foreign enterprises acting in the Portuguese market: Siemens, B.B.C, ASEA, Oerlikon, etc. We can also establish a relationship between the development of the electric network and the growth of production and consumption of electricity in the principal urban centres. Finally we see how foreign firms were a stimulus to the creation of national enterprises, especially those of small scale, in Portugal.