Validation of a SPE clean-up method for ochratoxin A determination in red wine

ICFC 2017 - International Conference on Food Contaminants (Book of Abstracts)The quality of Portuguese wines has improved considerably during the last decades as modern viticulture and enological practices were adopted. To maintain high quality standards it is also important to control any hazard that may jeopardize wine safety. On e potential hazard for wines is the occurrence of the mycotoxin, ochratoxin A (OTA). This fungal metabolite occurs and exerts its toxic effects in small quantities, thus sensitive and reliable methods are required for monitoring its occurrence in foods. In order to minimize the interfering effect of the matrix and improve the selectivity and sensitivity of the analytical method, a concentration and cleaning step is often necessary. Solid phase extraction (SPE) is a technique with numerous advantages for that purpose. The objective of this work was to optimize and validate an analytical method for the determination of OTA in red wine using the SPE column Strata-X-A (Phenomenex). A not contaminated local red wine was fortified with OTA at concentrations of 0.0 5 to 10 μg/L, samples were clean - up using Strata - X - A columns in triplicate, analyzed by HPLC with fluorescence detection, and method recoveries, selectivity, stability, linearity, limit of detection (LOD), and limit of quantification (LOQ) determined. The method showed a linear response within the concentration range of 0.05 to 10 μg/L with a correlation coefficient of 0.9999. Within this concentration range, recoveries varied between 111% and 87%, respectively. The intra - day RSD was below 8%. The LOD and LO Q of the method was 0.005 and 0.015 μg/L, respectively. Portuguese red wines were analyzed using this method. Four wines did not reveal any OTA, and seven add OTA in concentrations that ranged between 0.02 and 0.441 μg/L. In conclusion, 20 years after the first studies reporting the presence of OTA in wines, levels of this mycotoxin in Portuguese wines are still lowinfo:eu-repo/semantics/publishedVersio

Enzyme production by solid-state fermentation

Solid-state fermentation (SSF) is a fermentation process which uses moist solid supports (mainly, agro-industrial residues) as substrate. This process has many advantages when compared with submerged fermentation (SmF) and is being successfully exploited for the production of enzymes and secondary metabolites. Its advantages include higher fermentation productivity, higher concentration of the products, less catabolic repression, low water and energy demanding, less effluent generation, and requirement of simple fermentation equipments [1]. This research group has been working in the production of fungi enzymes using SSF. Recently, we reported the production, isolation and purification of an ochratoxin A (OTA) hydrolytic enzyme [2]. This enzyme was produced by SSF on wheat germ and purified from the culture filtrate by acetone precipitation and anion exchange chromatography. The isolated enzyme is a metalloenzyme which can degrade OTA at pH 7.5 and 37 ºC, allowing its detoxification. OTA is a mycotoxin produced by several fungi in some agricultural commodities being present in food and feed products. Presently, we are assessing the application of this enzyme on detoxification processes for some agricultural commodities

Solitary practices or social connections? : a comparative study of fathering and health experiences among white and African-Caribbean working class men

This study addresses the following research question: what are the implications of African- Caribbean and White working class men's experiences within social connections (within families, friendships, communities and workplaces), for fathering and health experiences? The purposes of this study were to undertake a primary piece of intensive qualitative research, and also to analyse, critically, the study's findings, in order to identify implications for theory, policy, practice and research. This investigation was critical, interpretative and exploratory, informed by the principles of phenomenology and ethnography. Six African-Caribbean and seven White working class men were recruited, using purposive sampling, for two semi-structured individual interviews. This enabled the exploration of the interactive effects and processes of structure and agency, in relation to social class, gender, and ethnicity. The study did not find major differences between the experiences of these two groups of men, although the assets and constraints related to African-Caribbean men's experiences of ethnicity and racism within social connections were evident. Study findings, for both groups of men, indicated that social connectedness within families, communities and workplaces was highly valued, but social connections, material and structural factors also influenced the health of the men interviewed. Furthermore, findings indicated that men's experiences of social connectedness have limitations. Specifically, men's limited insights into the links between social connectedness and health, men's perceived limitations with their communication skills, their solitary methods of dealing with perceived vulnerability, but also the uncertainty associated with their identities as men were significant findings. Indeed, men's experiences of both solitary discourses and practices and social connectedness, regarding fathering and health, were associated with discourses about masculinities. Implications for existing theory, for example Connell's (1995) work regarding masculinities, and Putnam's (1995) work regarding `social capital', are identified. In addition, implications for research, policy and practice are examined, with specific reference to the opportunities for mental health promotion with working class men who are fathers

Isolation and purification of an enzyme hydrolyzing ochratoxin A from aspergillus niger

Ochratoxin A is a mycotoxin produced by several Aspergillus and some Penicillium species which may be present in food and feed products. It can be enzymatically hydrolyzed into ochratoxin α and l-β-phenylalanine, thereby decreasing its toxicity. The ochratoxin A degradation capacity of Aspergillus niger is well known and here we report the isolation and purification of a novel enzyme from A. niger that hydrolyzes this mycotoxin. A wheat germ medium supplemented with ochratoxin A was used to produce the enzyme, which was purified from culture filtrate by acetone precipitation and anion exchange chromatography. An overall purification of 2.5-fold with a recovery of 68% and a final specific activity of 36 U/mg was obtained. The enzyme is a metalloenzyme as it was inhibited at 10 mM EDTA, whereas PMSF had no effect. The ochratoxin A hydrolytic enzyme presented a V max of 0.44 μM/min and a K m of 0.5 mM when the reaction was carried out at pH 7.5 and 37°C.Fundação para a Ciência e a Tecnologia (FCT

Congenital defects of the middle ear-uncommon cause of pediatric hearing loss

INTRODUCTION: In children, hypoacusis, or conductive hearing loss, is usually acquired; otitis media with effusion is the most common etiology. However, in some cases this condition is congenital, ranging from deformities of the external and middle ear to isolated ossicular chain malformations. The non-ossicular anomalies of the middle ear, for instance, persistent stapedial artery and anomaly of the facial nerve, are uncommon but may accompany the ossicular defects. OBJECTIVE: This study aimed to describe the clinical presentation, diagnostic tests, and therapeutic options of congenital malformations of the middle ear. METHODS: This was a retrospective study of cases followed in otolaryngologic consultations since 2007 with the diagnosis of congenital malformation of the middle ear according to the Teunissen and Cremers classification. A review of the literature regarding the congenital malformation of the middle ear and its treatment is presented. CONCLUSION: Middle ear malformations are rarely responsible for conductive hearing loss in children. As a result, there is often a late diagnosis and treatment of these anomalies, which can lead to delays in the development of language and learnin

Aspectos do controlo da qualidade da fluodesoxiglucose num laboratório de produção

Resumo do poster apresentado ao XII Congresso Nacional de Medicina Nuclear, 12-14 Novembro 2009, Mealhad

Nanoemulsions for enhancement of curcumin bioavailability and their safety evaluation: effect of emulsifier type

This work aimed at evaluating the effects of different emulsifiers on curcumin-loaded nanoemulsions behavior during digestion, its safety and absorption, to develop nanoemulsions that provide safety and improved curcumin functionality. Nanoemulsions (NEs) were produced using two bio-based (lecithin (LEC) and rhamnolipids (RHAM)) and one synthetic (Tween®80 (TWE)) emulsifier at similar concentrations. Different NEs were subjected to in vitro digestion. The cytotoxicity and permeability tests were performed in Caco-2 cells. NE_TWE were stable during all phases of in vitro digestion, whereas NE_LEC and NE_RHAM were found to be unstable from the gastric phase. NE_TWE showed 100% of free fatty acids released, followed by NE_RHAM and NE_LEC. Curcumins bioaccessibility and stability increased in the following order: NE_LEC > NE_RHAM > NE_TWE. NE_LEC and NE_TWE did not show cytotoxic effects in any of the concentrations tested, while NE_RHAM presented high cytotoxicity in all concentrations tested. The apparent permeability coefficients were determined for NE_LEC and NE_TWE; however, the results were not statistically different. These results showed that the emulsifier used has a high impact on nanoemulsions behavior under the digestion process and on their cytotoxicity. This work contributed to the state-of-the-arts progress on the development of safer curcumin delivery systems with improved functionality, particularly regarding the proper selection of ingredients to produce said systems.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and under the scope of project PTDC/AGR-TEC/5215/2014.info:eu-repo/semantics/publishedVersio

Anti-aflatoxigenic effect of organic acids produced by Lactobacillus plantarum

ICFC 2017 - International Conference on Food Contaminants (Book of Abstracts)Molds play an important role in food spoilage, being estimated that 5 to 10% of the world food’s production is lost due to fungal contamination. Further, certain fungal species produce highly toxic metabolites, designated as mycotoxins. Biopreservation, de fined as the control of one organism by another, has received much attention in recent years. Also, some strains of lactic acid bacteria (LAB) that demonstrated antifungal and antimycotoxin properties gained interest to be used as natural biopreservatives. In this work, it is shown that the cell free supernatant (CFS) of Lactobacillus plantarum UM55 inhibited the growth of aflatoxigenic fungi, Aspergillus flavus , by 32% and the production of aflatoxins (AFs) by 91%. These inhibitions were lost when the CFS pH was neutralized. Additionally, it was observed an increase of the inhibitions with increasing concentration of CFS. Other aflatoxigenic strains, such as A. parasiticus , A. arachidicola , A. nomius and A. minisclerotigenes were inhibited by the CFS of the bacterium in different extents. Organic acids present in CFS were quantified, with main differences between CFS and control found in the levels of lactic acid, phenyllactic acid (PLA), hydroxyphenyllactic acid (OH - PLA) and indole lactic acid (ILA). When t ested, individually against A. flavus , all the compounds were able to inhibit fungal growth and AFs production. PLA showed the stronger effects and the 90% inhibitory concentration (IC90) for fungal growth and AFs was of 11.9 and 0.87 mg/mL, respectively. AFLs IC90 for ILA, OH - PLA and lactic acid were of 1.47, 1.80, and 3.92 mg/mL, respectively. Inhibitory effects of L. plantarum UM55 seems to be related to the production of lactic acid, PLA, OH-PLA and ILASFRH/BD/103245/2014 from the Portuguese Foundation for Science and Technology (FCT). Luís Abrunhosa was supported by grant UMINHO/BPD/51/2015 from project UID/BIO/04469/2013 financed by FCT/MEC (OE). This study was supported by FCT under the s cope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684); of BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 -Programa Operacional Regional do Norte; and under the scope of the projects RECI/BBB-EBI/0179/2012 (FCOMP - 01 - 0124 - FEDER - 027462)info:eu-repo/semantics/publishedVersio

Radiosynthesis and in vivo evaluation of a 18F-labelled styryl-benzoxazole derivative for β-amyloid targeting

The formation of β-amyloid deposits is considered a histopathological feature of Alzheimer′s disease (AD). In vivo molecular imaging by means of amyloid-avid radiotracers will allow for an early and conclusive diagnostic of AD. Herein, we describe the radiosynthesis of the radiofluorinated styryl benzoxazole derivative [18F]-[2-[N-methyl-N-(2′-fluoroethyl)-4′-aminostyryl]benzoxazole] ([18F]-1) and its pre-clinical evaluation, including metabolic and biodistribution studies in male Wistar rats. The in vivo biological evaluation of [18F]-1 showed that this new radiotracer has a moderate brain uptake with a slow brain washout and a poor in vivo stability