Effects of photosynthate manipulation on biological nitrogen fixation in common bean plants

Em dois experimentos, conduzidos em casa de vegetação, procurou-se verificar o efeito da disponibilidade de carbono para os nódulos na fixação biológica de nitrogênio em feijoeiro (Phaseolus vulgaris L.). A retirada das flores aumentou, inicialmente, a atividade da nitrogenase, a eficiência relativa dos elétrons destinados à nitrogenase (ER) e a taxa de translocação dos compostos nitrogenados na seiva do xilema, mas dentro de dez dias houve uma queda drástica nesses parâmetros, em virtude da aceleração no processo de  senescência dos nódulos. A retirada de 50% das folhas no florescimento provocou um declínio na atividade da nitrogenase, na ER e no transporte de N na seiva do xilema, mas, após dez dias, iniciou-se uma recuperação, atribuída à produção de folhas novas, o que não ocorreu quando a retirada das folhas foi realizada no período médio de enchimento dos grãos. O  anelamento do caule do feijão, impedindo a translocação de  fotossintatos para os nódulos, provocou uma queda na atividade da nitrogenase, na ER e no transporte de N na seiva, mas o decréscimo na atividade da nitrogenase só ocorreu 24 horas após o anelamento, indicando que no sistema radicular de feijão há uma quantidade considerável de substratos de reserva para a fixação de nitrogênio.Two experiments were performed, under greenhouse conditions, to investigate the effect of availability of carbon to the nodules on biological nitrogen fixation in common bean plants. Removal of flowers initially increased nitrogenase activity, relative efficiency of electrons for nitrogenase (RE) and rate of nitrogen translocation in the xylem sap, but within ten days all these parameters decreased due to an acceleration of nodule senescence. The removal of 50% of the leaves at flowering decreased nitrogenase activity, RE and N translocation in the xylem sap, but after ten days the plants began recover in these parameters due to the production of new leaves, which did not happen when the leaves where removed at mid-pod filling stage. The stem ringing, hampering translocation of photosynthates to the nodules, decreased nitrogenase activity, RE, and N transport in xylem sap, but the decrease in nitrogenase activity occurred 24 hours after ringing, indicating that in bean roots there is a considerable quantity of stored substrates for N2 fixation

Interação entre cultivares de Phaseolus vulgaris e estirpes de Rhizobium na fixação e transporte do nitrogênio

One experiment was performed, under greenhouse conditions, using five cultivars of Phaseolus vulgaris L. and six strains of Rhizobium leguminosarum biovar phaseoli to evaluate the nitrogen fixation and transport in the plants. Both cultivars and strains affected significantly the dry weight and total P4 of leaves, stems and pods; nodule dry weight; nodule efficiency (mg N. g nod-1); nitrogenize activity; H2evolution by the nodules; relative efficiency (RE); N concentration and rate of N translocation in the xylem sap and percentage of the N of the xylem sap as ureides. The parameters (estimated at flowering time, 35 days after germination) that showed best correlations with total N of pods at 50 days were: RE (0.872**), rate of N translocation in the xylem sap (0.949**) and percentage of N as ureides in the xylem sap (0.907**). A positive correlation was found between RE and percentage of N as ureides (0.903**), and this can be best explained in terms of a relationship between H2 metabolism and ureide metabolism.Utilizaram-se cinco cultivares de Phaseolus vulgaris L. e seis estirpes de Rhizobium leguminosarum biovar phaseoli em um experimento conduzido sob condições de casa de vegetação. Foram observados efeitos da cultivar e da estirpe nos seguintes parâmetros: peso seco e N total acumulado nas folhas, caules e vagens; peso seco dos nódulos; eficiência dos nódulos (mg N.g nódulo-1); atividade da nitrogenase; evolução do H2 pelos nódulos; eficiência relativa dos elétrons destinados à nitrogenase (ER); concentração de N total na seiva do xilema; taxa de translocação do N na seiva do xilema e percentagem do N total da seiva sob a forma de ureídos. Os parâmetros (avaliados no florescimento, aos 35 dias após a germinação) que apresentaram as melhores correlações com o N total das vagens aos 50 dias foram: ER (0,872**), taxa de translocação do N na seiva do xilema (0,949**) e percentagem do N sob a forma de ureídos (0,907**). Encontrou-se uma correlação positiva entre a ER e a percentagem N-ureído (0,903**), o que pode ser atribuído a uma possível relação entre o metabolismo do H2 e o metabolismo dos ureídos

An insight on the role of photosensitizer nanocarriers for Photodynamic Therapy

Photodynamic therapy (PDT) is a modality of cancer treatment in which tumor cells are destroyed by reactive oxygen species (ROS) produced by photosensitizers following its activation with visible or near infrared light. The PDT success is dependent on different factors namely on the efficiency of the photosensitizer deliver and targeting ability. In this review a special attention will be given to the role of some drug delivery systems to improve the efficiency of tetrapyrrolic photosensitizers to this type of treatment.publishe

Fixação de nitrogênio, tipo de nódulo e ocorrência de ureídos em leguminosas florestais

A study of 36 legume trees was made with the objective of relating nitrogen fixation, morphology of nodules and the utilization of ureides in nitrogen transport. Nodulation and acetylene reduction activity were detected in 35 species and ureides in all 36. The greatest concentrations of ureides were observed in certain species of the tribe Dalbergieae which had nodules of the globular type.Foi feito um levantamento em 36 leguminosas florestais, com o objetivo de relacionar a fixação de nitrogénio com a morfologia dos nódulos e com a utilização de ureídos no transporte de nitrogênio. Foi detectada nodulação da atividade da nitrogenase (redução de acetileno) em 35 e ureídos em todas as 36 espécies estudadas. As maiores concentrações de ureídos foram observadas em algumas espécies da tribo Dalbergieae que possuem nódulos do tipo globoso

The microbial culture collections of the Federal University of Pernambuco (UFPE) and the new consortium towards the establishment of BRC-UFPE

The UFPE from Recife in Brazil hosts a bacterial (UFPEDA) and a fungal (URM) collections since 1951 and 1954, respectively. The UFPEDA was established by Prof. Oswaldo Gonçalves de Lima and is register in WDCM as 114. It is hosted at Antibiotic Department (DA) of UFPE and started out with 200 species mainly of the genus Streptomyces. Nowadays this collection holds 4000 strains of actinomycetes isolated from all the Brazilian places and from the International Streptomyces Project (ISP). The URM – University of Recife Mycology was established by Prof. Augusto Chaves Batista and is register in WDCM as 604. Actual it holds 9000 identified species including 1400 yeasts and 7600 filamentous fungi. All major fungal taxonomic groups are cover by this collection. The collections preserve each strain at least by two different techniques. Water and mineral oil storage were used for long operation time while freeze-drying and freezing at -80 ºC become the main techniques used at this stage. Special care is taken to test whether cultures recovered from preserved material conform to the original deposit. These collections have a range of services which are acceptance of free and confidential deposits, supply strains for academia, industry and services, support research and education (graduate and post-graduate students, as well as advanced training courses), identification services and confidential contracts (e.g. fungal medical diagnosis, starters for agro-industry companies, etc.). The OECD initiative related to guidance for the operation of Biological Resource Centres (BRC) is now a key reference for these collections. The right management of biological resources and their associate information including quality control are perused by these collections. The recent national projects, with reasonable budgets to support their activities, either on networking activities or requalification and management create a new breath and responsibilities to these collections. Taking advantage of good and well equipped premises of LIKA these collections are now open new avenues working in consortium to improve the quality control of their holdings using new tools from molecular biology and spectral analysis (MALDI-TOF) to achieve in the future a certified BRC for the UFPE microbial culture collections

Migration routes and non-breeding areas of Common Terns (Sterna hirundo) from the Azores

We describe the migration routes and non-breeding areas of Common Terns (Sterna hirundo) from the Azores Archipelago, based on ringing (banding) recoveries and tracking of three birds using geolocators. Over 20 years, there have been 55 transatlantic recoveries of Common Terns from the Azores population: six from Argentina and 49 from Brazil. The three tracked birds migrated south in different months (August, September, November), but the northern migration was more synchronous, with all leaving in April. The birds were tracked to three areas of the South American coast: the male spent November–April on the northern Brazilian coast (13°N–2°S), whereas the two females first spent some time off central-eastern Brazil (4–16°S; one for 1 week, the other for 3 months) and then moved south to the coast of south-eastern Brazil, Uruguay and northern Argentina (24–39°S). Although caution is needed given the small sample size and errors associated with geolocation, the three tracked terns potentially travelled a total of ~23 200 km to and returning from their non-breeding areas, representing an average movement of ~500 km day–1. With the exception of Belém, in northern Brazil, and Lagoa do Peixe, in southern Brazil, the coastal areas used by the tracked birds were also those with concentrations of ringing recoveries, confirming their importance as non-breeding areas for birds from the Azores

New nitroindazole-porphyrin conjugates: synthesis, characterization and antibacterial properties

The synthesis of new porphyrin-indazole hybrids by a Knoevenagel condensation of 2-formyl-5,10,15,20-tetraphenylporphyrin and N-methyl-nitroindazolylacetonitrile derivatives is reported. The target compounds were isolated in moderate to good yields (32-57%) and some of the isolated porphyrin-indazole conjugates showed good performance in the generation of singlet oxygen when irradiated with visible light. Their efficiency as photosensitizers in the photoinactivation of methicillin resistant Staphylococcus aureus-MRSA was evaluated. All derivatives showed to be able to photoinactivate the MRSA bacteria. Compound 3a appears to be the most promising photosensitiser (PS) in the photoinactivation of these bacteria, despite being the least efficient in singlet oxygen generation. The addition of potassium iodide (KI) significantly potentiated the antimicrobial Photodynamic Therapy (aPDT) process mediated by all the analysed porphyrin-indazole conjugates. The combined action of nitroindazole-porphyrins with potassium iodide (KI) action appears to be promising in the photoinactivation of MRSA.publishe

Psicologia da Educação no Instituto Superior de Engenharia do Porto: Projecto Caminhos de Bolonha

Este artigo apresenta a síntese da intervenção em Psicologia da Educação no Instituto Superior de Engenharia do Porto, no âmbito do Projecto Caminhos de Bolonha. O objectivo que norteia as actividades deste Projecto tem sido, desde o seu início, o apoio do Conselho Científico do ISEP na operacionalização do projecto de modernização e inovação do processo ensino aprendizagem no ISEP, induzido pela adesão ao processo de Bolonha.info:eu-repo/semantics/publishedVersio

Echinacea purpurea fractions represent promising plant-based anti-inflammatory formulations

Echinacea purpurea is traditionally used in the treatment of inflammatory diseases. Therefore, we investigated the anti-inflammatory capacity of E. purpurea dichloromethanolic (DE) and ethanolic extracts obtained from flowers and roots (R). To identify the class of compounds responsible for the strongest bioactivity, the extracts were fractionated into phenol/carboxylic acid (F1) and alkylamide fraction (F2). The chemical fingerprint of bioactive compounds in the fractions was evaluated by LC-HRMS. E. purpurea extracts and fractions significantly reduced pro-inflammatory cytokines (interleukin 6 and/or tumor necrosis factor) and reactive oxygen and nitrogen species (ROS/RNS) production by lipopolysaccharide-stimulated primary human monocyte-derived macrophages. Dichloromethanolic extract obtained from roots (DE-R) demonstrated the strongest anti-inflammatory activity. Moreover, fractions exhibited greater anti-inflammatory activity than whole extract. Indeed, alkylamides must be the main compounds responsible for the anti-inflammatory activity of extracts; thus, the fractions presenting high content of these compounds presented greater bioactivity. It was demonstrated that alkylamides exert their anti-inflammatory activity through the downregulation of the phosphorylation of p38, ERK 1/2, STAT 3, and/or NF-κB signaling pathways, and/or downregulation of cyclooxygenase 2 expression. E. purpurea extracts and fractions, mainly DE-R-F2, are promising and powerful plant-based anti-inflammatory formulations that can be further used as a basis for the treatment of inflammatory diseases.This work was financially supported by the FCT to the Ph.D. grants of S.F.V. (PD/BD/135246/2017 and COVID/BD/152012/2021), S.M.G. (SFRH/BD/136814/2018), and C.C. (CEECIND/04058/2018), and the projects PATH (PD/00169/2013), HEALTH-UNORTE (NORTE-01- 0145-FEDER-000039) and the NORTE 2020 Structured Project, co-funded by Norte2020 (NORTE-01- 0145-FEDER-000021