Synthesis of Dehydrodipeptide and N-ethyl-dehydrodipeptide Derivatives with an α-Aminoisobutyric Acid Residue

Several dipeptides with an N-benzyloxycarbonyl or an N-(tert-butyloxycarbonyl) α-aminoisobutyric acid residue and a β-hydroxyamino acid methyl ester were subjected to dehydration to form dehydrodipeptide derivatives. N-Ethylation of these dipeptides using triethyloxonium tetrafluoroborate with potassium tert-butoxide as auxiliary base led to complex mixtures that failed to render pure products. However, when the 4-nitrophenylsulfonyl protecting group was substituted for the benzyloxycarbonyl or tert-butyloxycarbonyl groups and N,N-diisopropylethylamine was substituted for potassium tert-butoxide, the dehydrodipeptide derivatives were selectively N-alkylated at the amino terminal nitrogen in fair to high yields. Alternatively, N-ethylation can be carried out prior to dehydration. Thus, through a combination of dehydration and N-ethylation procedures, it was possible to obtain dipeptides with α-aminoisobutyric acid and dehydroamino acid residues, which are N-alkylated at the amino terminal nitrogen.Foundation for Science and Technology (FCT) – Portugal and Fundo Europeu de Desenvolvimento Regional (FEDER) for financial support to Chemistry Centre of University of Minho. The NMR spectrometer Bruker Avance II+ 400 is part of the National NMR Network and was purchased in the framework of the National Program for Scientific Re-equipment; contract REDE/1517/RMN/2005, with funds from POCI 2010, FEDER and FCT.info:eu-repo/semantics/publishedVersio

The effect of phosphate-solubilizing rhizobacteria on Zea mays growth on P-deficient soils

P-deficiency in soils is a limiting factor for plant growth. Several phosphate-solubilizing rhizobacteria (PSB) were used to enhance growth of Zea maysgrowing in a P-deficient soil. Strains were screened for their ability to solubilize P and to produce plant growth promoting (PGP) substances. The best-P solubilizing strains Rhodococcus sp. EC35, Pseudomonas sp. EAV and Arthrobacter nicotinovoransEAPAA were inoculated in maize growing in P-deficient soils without P fertilization and amended with soluble (KH2PO4) and insoluble P (Ca3(PO4)2). Results showed that PSB significantly enhanced Z. mays biomass production in all Ptreatments. Without P fertilization, bacterial inoculation increased plant dry biomass by ca. 20%, while under soluble P conditions the enhancement was higher. Pseudomonas sp. EAV was the strain that better performed improving rootand shoot biomass by 104% and 60%, respectively. In soils amended with insoluble P, plant biomass was also positive influenced by bacterial inoculation. Plant growth enhancement seems to be related not only to Psolubilization but also to other PGP traits, such as IAA and ACC-deaminase. This work shows that PSB may be used as bioinoculants and consequently constitute an attractive alternative to the phosphatic fertilizers amendments used to improve crop production

From nose to nuisance: A collaborative approach to assess the odour problem in an oilseed plant

Odour nuisance is an ignored environmental problem, an invisible face of air quality analysis and monitoring in Portugal. Local and governmental authorities have been receiving odour complaints, but only in recent years this issue is seen as a growing concern and not just a matter of licensing and inspection. This fact and the lack of specific ambient air odour regulation in Portugal originated a bottom up approach focused on citizens and their contribution to a more comprehensive analysis. Despite the existence of odour measuring instruments, the human nose is a universal sensor with higher sensitivity that allows to assess the impact of discomfort on sensitive receptors. From this point of view, a sensorial method has been conducted with community neighbours of an odour emission source as an integrative approach to the problem and a complementary vector to a quantitative analysis. The human nose used as a "tool", allows to address the issue instantly and at a local level, which is not always possible with other methodologies, even in situations where the detection limit is reduced and therefore not measurable with certain equipment. It should be noted that this olfactory evaluations are the ones responsible for triggering formal complaints to the authorities whether it is the National Guard, the municipality or the environmental regulators. But the lack of a unified form to register the complaints is a mandatory issue to help addressing the correct odour sources and better understand the problem. So, this sensorial approach also aims to develop a tool to aggregate the needed elements to a valid form, to ensure that the complaints can be verified and validated. This would help to make a comparison and create a record history database, at the odour emitter level or at local and national scale. The results obtained with this approach have led to the application of several actions such as the real knowledge of the problem from an industrial operator perspective, inclusion of public stakeholders, and the design and implementation of an odour management plan with the purpose of the establishment of mitigation measures.publishersversionpublishe

A simple method to measure sulfonation in man using paracetamol as probe drug

Sulfotransferase enzymes (SULT) catalyse sulfoconjugation of drugs, as well as endogenous mediators, gut microbiota metabolites and environmental xenobiotics. To address the limited evidence on sulfonation activity from clinical research, we developed a clinical metabolic phenotyping method using paracetamol as a probe substrate. Our aim was to estimate sulfonation capability of phenolic compounds and study its intraindividual variability in man. A total of 36 healthy adult volunteers (12 men, 12 women and 12 women on oral contraceptives) received paracetamol in a 1 g-tablet formulation on three separate occasions. Paracetamol and its metabolites were measured in plasma and spot urine samples using liquid chromatography-high resolution mass spectrometry. A metabolic ratio (Paracetamol Sulfonation Index-PSI) was used to estimate phenol SULT activity. PSI showed low intraindividual variability, with a good correlation between values in plasma and spot urine samples. Urinary PSI was independent of factors not related to SULT activity, such as urine pH or eGFR. Gender and oral contraceptive intake had no impact on PSI. Our SULT phenotyping method is a simple non-invasive procedure requiring urine spot samples, using the safe and convenient drug paracetamol as a probe substrate, and with low intraindividual coefficient of variation. Although it will not give us mechanistic information, it will provide us an empirical measure of an individual's sulfonator status. To the best of our knowledge, our method provides the first standardised in vivo empirical measure of an individual's phenol sulfonation capability and of its intraindividual variability. EUDRA-CT 2016-001395-29, NCT03182595 June 9, 2017.publishersversionpublishe

Synthesis of N-alkyl-C α, α-dimethylglycine derivatives

The application of trialkyloxonium tetrafluoroborates for N-alkylation of the nonnatural amino acid Cα, α-dimethylglycine is described. Several methyl esters of dimethylglycine protected with different amine protecting groups were subject to N-ethylation or N-methylation with triethyloxonium tetrafluoroborate or trimethyloxonium tetrafluoroborate, respectively. The corresponding N-akyl-Cα, α-dimethylglycine derivatives were obtained in good to high yields. Removal of the methyl ester rendered amino acid derivatives ready for application in peptide synthesis.Foundation for Science and Technology (FCT) – Portugal and Fundo Europeu de Desenvolvimento Regional (FEDER) for financial support to Chemistry Centre of University of Minho. The NMR spectrometer Bruker Avance II+ 400 is part of the National NMR Network and was purchased in the framework of the National Program for Scientific Re-equipment; contract REDE/1517/RMN/2005, with funds from POCI 2010, FEDER and FCT.info:eu-repo/semantics/publishedVersio

Current challenges and future perspectives

: The research group was funded by IPOLFG EPE and by iNOVA4Health (UID/Multi/04462/2019) a program financially supported by Fundação para a Ciência e Tecnologia (FCT)/Ministério da Educação e Ciência, through national funds. We also acknowledge funding from FCT-MCTES through Filipa Lopes-Coelho PhD (PD/BD/128337/2017).Anti-angiogenic therapy is an old method to fight cancer that aims to abolish the nutrient and oxygen supply to the tumor cells through the decrease of the vascular network and the avoidance of new blood vessels formation. Most of the anti-angiogenic agents approved for cancer treatment rely on targeting vascular endothelial growth factor (VEGF) actions, as VEGF signaling is considered the main angiogenesis promotor. In addition to the control of angiogenesis, these drugs can potentiate immune therapy as VEGF also exhibits immunosuppressive functions. Despite the mechanistic rational that strongly supports the benefit of drugs to stop cancer progression, they revealed to be insufficient in most cases. We hypothesize that the rehabilitation of old drugs that interfere with mechanisms of angiogenesis related to tumor microenvironment might represent a promising strategy. In this review, we deepened research on the molecular mechanisms underlying anti-angiogenic strategies and their failure and went further into the alternative mechanisms that impact angiogenesis. We concluded that the combinatory targeting of alternative effectors of angiogenic pathways might be a putative solution for anti-angiogenic therapies.publishersversionpublishe

druggable targets in cancer

Funding: iNOVA4Health—UID/Multi/04462/, a programme financially supported by Fundação para a Ciência e a Tecnologia-Ministério da Educação e Ciência (FCT-MCTES) through national funds.To enable survival in adverse conditions, cancer cells undergo global metabolic adaptations. The amino acid cysteine actively contributes to cancer metabolic remodelling on three different levels: first, in its free form, in redox control, as a component of the antioxidant glutathione or its involvement in protein s-cysteinylation, a reversible post-translational modification; second, as a substrate for the production of hydrogen sulphide (H2S), which feeds the mitochondrial electron transfer chain and mediates per-sulphidation of ATPase and glycolytic enzymes, thereby stimulating cellular bioenergetics; and, finally, as a carbon source for epigenetic regulation, biomass production and energy production. This review will provide a systematic portrayal of the role of cysteine in cancer biology as a source of carbon and sulphur atoms, the pivotal role of cysteine in different metabolic pathways and the importance of H2S as an energetic substrate and signalling molecule. The different pools of cysteine in the cell and within the body, and their putative use as prognostic cancer markers will be also addressed. Finally, we will discuss the pharmacological means and potential of targeting cysteine metabolism for the treatment of cancer.publishersversionpublishe

Induction of stress tolerance in Lactobacillus delbrueckii ssp. bulgaricus by the addition of sucrose to the growth medium

The lactic acid bacteria (LAS) play an important role in the production of fermented foods. The development of concentrated cultures of LAS, for inoculating the production vat directly (bulk starters), has eliminated many problems traditionally involved in their preparation and maintenance by the food industry. For industrial use, LAS are often preserved in a frozen or dried form, the latter preparations having lower transport and storage costs (Kets et aI. 1996). Dried cultures, however, lose viability/activity during storage, especially when kept at room temperature (Champagne et aI. 1991; Teixeira et aI. 1995a, b; Castro et aI. 1996). Attempts to improve the survival of LAS during drying have already been tried (Linders et aI. 1997b; Gardiner et aI. 2000). Previous results indicated a direct relationship between the presence of compatible solutes in LAS and their ability to survive drying conditions. Such solutes include amino acids, amino acid derivatives, quaternary amines, sugars and tetrahydropyrimidines (Kets & De Sont, 1994; Kets et aI. 1994, 1996). It has been reported for severa I strains of lactobacilli that these organisms are probably unable to accumulate compatible solutes during the very short period of the drying process, and therefore they should be accumulated prior to the drying process (Kets & De Sont, 1994; Leslie et aI. 1995; Kets et aI. 1996; Linders et aI. 1997b). The aim of the present work was to investigate the effect of adding sucrose to the growth medium of Lactobacil/us delbrueckii ssp. bulgaricus on its survival during heating, spray drying and during the time of storage.info:eu-repo/semantics/publishedVersio

Development of new analytical tools for monitoring of cardiovascular disease markers – towards the detection of homocysteine-thiolactone

Poster presented at the 4th International Conference on Bio-Sensing Technology, 10-13 May 2015, Lisbon, Portuga

A Comparative Genomic Analysis of Energy Metabolism in Sulfate Reducing Bacteria and Archaea

The number of sequenced genomes of sulfate reducing organisms (SRO) has increased significantly in the recent years, providing an opportunity for a broader perspective into their energy metabolism. In this work we carried out a comparative survey of energy metabolism genes found in 25 available genomes of SRO. This analysis revealed a higher diversity of possible energy conserving pathways than classically considered to be present in these organisms, and permitted the identification of new proteins not known to be present in this group. The Deltaproteobacteria (and Thermodesulfovibrio yellowstonii) are characterized by a large number of cytochromes c and cytochrome c-associated membrane redox complexes, indicating that periplasmic electron transfer pathways are important in these bacteria. The Archaea and Clostridia groups contain practically no cytochromes c or associated membrane complexes. However, despite the absence of a periplasmic space, a few extracytoplasmic membrane redox proteins were detected in the Gram-positive bacteria. Several ion-translocating complexes were detected in SRO including H+-pyrophosphatases, complex I homologs, Rnf, and Ech/Coo hydrogenases. Furthermore, we found evidence that cytoplasmic electron bifurcating mechanisms, recently described for other anaerobes, are also likely to play an important role in energy metabolism of SRO. A number of cytoplasmic [NiFe] and [FeFe] hydrogenases, formate dehydrogenases, and heterodisulfide reductase-related proteins are likely candidates to be involved in energy coupling through electron bifurcation, from diverse electron donors such as H2, formate, pyruvate, NAD(P)H, β-oxidation, and others. In conclusion, this analysis indicates that energy metabolism of SRO is far more versatile than previously considered, and that both chemiosmotic and flavin-based electron bifurcating mechanisms provide alternative strategies for energy conservation