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

Antifungal and antiaflatoxigenic properties of Lactobacillus species

Molds play an important role in spoilage of food products. It is estimated that 5 to 10% of the world foods production is lost due to fungal contamination. Further, certain fungal species produce highly toxic metabolites designated as mycotoxins. According to FAO, up to 25% of the worlds food crops have been estimated to be significantly contaminated with mycotoxins. Among all known mycotoxins, aflatoxins are the most relevant ones because they are carcinogenic. Biopreservation, defined as the control of one organism by another, has received much attention by researchers in recent years. In this field, lactic acid bacteria (LAB) are of great interest to be used as natural biopreservatives of food and feed since they have extensive probiotic properties and have been traditionally used in fermentation processes. The aim of this work is to demonstrate the potential of Lactobacillus species to control the occurrence of aflatoxigenic fungi and aflatoxins in agricultural commodities. For that several aflatoxigenic species such as Aspergillus flavus, A. parasiticus, A. nomius, A. tamari, A. arachidicola, and A. minisclerotigenes were inoculated in triplicate in MEA supplemented with 10% of sterile supernatants of different Lactobacillus species obtained from liquid MRS cultures. Supernatants of most active strains inactivated with heat, proteases and NaOH (for pH neutralization) were also tested and compared with untreated ones. The fungal radial growth and the aflatoxin concentration produced in each plate were recorded and compared. L. casei and L. plantarum supernatants were found to be most active. Growth of Aspergillus flavus in MEA after 7 days was reduced approx. by 31% and 25%, respectively for each bacteria. Aflatoxins B1 and B2 production were inhibited approx. by 97 and 87%, respectively. The antifungal and antiaflatoxigenic activity of those strains was reverted when supernatants were treated with proteolytic enzymes or their pH adjusted to 7

Probiotic microcarrier: a continuous folate producer

The recommended daily intake of folate (B-complex vitamin) for an adult varies between 200-400 µg, being the intake of folate inefficient due its extremely unstable chemical forms. The aim of this work is the creation of model to folate in situ production using probiotics. However, three main issues need to be overcome: (a) probiotic bacteria should be protected towards the gastric medium (encapsulation); (b) microcarriers size should be smaller than 100 µm, to avoid modifying food texture; and (c) microcarriers should adhere to gut epithelium in order to increase bacteria residence time. Lactococcus lactis cremoris was grown in milk (30ºC). Alginate-based microcarriers were produced and three layers were built using the layer-by-layer technique in that worder: poly-L-lysine; sodium alginate; chitosan. Confocal microscopy was used to confirm the consequent adhesion of the layers (poly-L-lysine/FITC; chitosan/rhodamine). After production the microcarriers where put into a 10 mL solution of KCl-HCl (pH 2 - 1 hour), at 100 rpm and then into a PBS solution (pH 7.2 - 3 hours) in order to mimic the passage through the gastrointestinal tract. The utilization of free bacteria (LLC) in milk showed an increase of folate content in 4.73 µg/L after 6 h. The average size of the microcarriers from 21.01 ± 0.49 µm to 39.84 ± 0.79 µm when the pH increased from 2 to 7.2. The size averages obtained were smaller than 100 µm and showed a swelling capacity (particles duplicate their size upon passing from pH 2 to pH 7.2), being confirmed by confocal microscopy images the correct adhesion of the different layers after this experiment and the stability of the microcarriers. Microcarriers produced through LbL showed great potential for encapsulation of probiotics, allowing their protection against harsh gastrointestinal conditions, predicting their use as a microcarrier for in situ folate production

Antifungal effect of organic acids from lactic bacteria on Penicillium nordicum

ICFC 2017 - International Conference on Food Contaminants (Book of Abstracts)Lactic acid bacteria (LAB) have been gaining attention for the antifungal properties of some strains. The control of fungal growth is especially important since moulds are responsible for significant spoilage of food and feed. Additionally, they are able t o produce toxic compounds known as mycotoxins that cause serious health hazards. Some LAB strains have the ability to inhibit fungal growth and also the production of mycotoxins. In this work, cell free supernatants (CFS) of Lactobacillus plantarum UM55 and Lactobacillus buchneri UTAD104 were tested for the inhibition of Penicillium nordicum growth and ochratoxin A (OTA) production. Fungal growth was inhibited in only 18 and 11% by CFS of L. plantarum and L. buchneri, respectively. However, the production o f OTA was reduced approx. in 70% by both strains. In order to determine the nature of compounds responsible for this activity, CFS were subjected to heat, proteases and neutralization of pH. It was observed that CFS retained its inhibitory properties after being autoclaved and treated with proteases. However, when submitted to pH neutralization, CFS lost its activity. Some organic acids produced by these LAB strains were also tested for their inhibitory capacity. Calculation of inhibitory concentrations shown that butyric and propionic acids were the most effective in inhibiting P. nordicum growth and OTA production, followed by indole lactic acid (ILA), phenyllactic acid (PLA), acetic acid, hydroxyphenyllactic acid (OH-PLA) and lactic acid. CFS were analysed by HPLC - PDA for the quantification of those organic acids. For L. plantarum UM55 main differences were found in the levels of lactic acid, PLA, OH-PLA, and ILA. For L. buchneri UTAD104, levels of acetic, lactic and PLA were higher than in the control experiment. In conclusion, ability of LAB to inhibit mycotoxigenic fungi depends of strain capability to produce certain organic acids, and those acids may differ from strain to straininfo:eu-repo/semantics/publishedVersio

Mycotoxin production from fungi isolated from grapes

Aims: In order to assess the potential for producing mycotoxins, fungi were isolated from wine producing grapes. Methods and Results: The isolates were identified and Penicillium expansum, the most well recognized mycotoxin producer, was analysed for mycotoxin production by TLC. Many of the strains produced patulin and/or citrinin, often depending on whether they were grown on a grape or yeast extract sucrose media. Conclusions: Citrinin was produced by all strains grown in the yeast extract sucrose medium, but only one strain (from 51) was able to produce this compound in grape juice medium. Patulin was produced in the yeast extract medium by 20 strains and in grape juice medium by 33 strains. Significance and Impact of the Study: The presence of mycotoxins in wine producing grapes is discussed. Grapes contamination with patulin seems not to contribute to wine contamination, and no ochratoxin producing fungi was identified.The British Council, Conselho de Reitores das Universidades Portuguesas (CRUP) - Windsor Programme - grant no 29/00

Control of Aflatoxigenic fungi and mycotoxins production by lactobacillus species

Molds play an important role in spoilage of food products. It is estimated that 5 to 10% of the world foods production is lost due to fungal contamination. Further, certain fungal species produce highly toxic metabolites designated of mycotoxins. Aflatoxins are the most toxics because they are proven carcinogenic. Biopreservation, defined as the control of one organism by another, has received much attention in recent years. In this field, lactic acid bacteria (LAB) are of great interest to be used as natural biopreservatives since they have broad probiotic properties and have been used traditionally in fermentation processes. The aim of this work was to demonstrate the potential of Lactobacillus species to control the occurrence of aflatoxigenic fungi and their mycotoxins. For that, several aflatoxigenic species such as Aspergillus flavus, A. parasiticus, A. nomius, A. tamari, A. arachidicola and A. minisclerotigenes were cultured on MEA plates supplemented with 10% of sterile supernatant of different Lactobacillus species (obtained from liquid MRS cultures). Supernatants of most active strains inactivated with heat, proteases and NaOH (for pH neutralization) were also tested and compared with untreated ones. The fungal radial growth and the concentration of aflatoxins, cyclopiazonic acid and sterigmatocystin produced in each plate were determined and compared with controls. L. casei LAB55 and L. plantarum LAB7 supernatants were the most active strains. Radial growth of A. flavus after 7 days of incubation at 25 ºC was reduced approx. by 31% and 25%, respectively. Aflatoxins production were inhibited approx. by 97 and 87%, respectively. Those reduction decreased slightly over 24 days of cultivation reaching at the end, about 13% and 70% for both strains and for growth and aflatoxins, respectively. The inhibitory properties of those strains was reverted when supernatants were treated with proteolytic enzymes or their pH adjusted to 7.funded by FEDER through COMPETE and by FCT; Ref. FCOMP-01-0124-FEDER-028029 and PTDC/AGRTEC/3900/2012, grant Incentivo/EQB/LA0023/2014 from ON.2 – O Novo Norte

Enhancing the bioconversion of winery and olive mill waste mixtures into lignocellulolytic enzymes and animal feed by Aspergillus uvarum using a packed-bed bioreactor

Wineries and olive oil industries are dominant agro-industrial activities in southern European regions. Olive pomace, exhausted grape marc and vine shoot trimmings are lignocellulosic residues generated by these industries, which could be valued biotechnologically. In the present work these residues were used as substrate to produce cellulases and xylanases through solid-state fermentation using Aspergillus uvarum. For that, two factorial designs (32) were first planned to optimize substrate composition, temperature and initial moisture level. Subsequently, the kinectics of cellulolytic enzymes production, fungal growth and fermented solid were characterized, Finally, the process was performed in a packed-bed bioreactor. The results showed that cellulase activity improved with the optimization processes, reaching 33.56 U/g, and with the packed-bed bioreactor aeration of 0.2 L/min, reaching 38.51 U/g. The composition of fermented solids indicated their potential use for animal feed because cellulose, hemicellulose, lignin and phenolic compounds were partially degraded 28.08, 10.78, 13.3 and 28.32% respectively, crude protein was increased from 8.47% to 17.08%, and, the mineral contents meet the requirements of main livestock.J.M.S. was supported by Grant SFRH/BPD/84440/2012 from Fundacao para a Ciencia e Tecnologia (FCT), Portugal. L.A. was supported by Grant Incentivo/EQB/LA0023/2014 from O Novo Norte (ON.2). We thank FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the Project "BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes, Rer. NORTE-07-0124-FEDER-000028" co-funded by the Programa Operacional Regional do Norte (ON.2), QREN, FEDE

Do incarcerated male juvenile recidivists differ from first-time offenders on self-reported psychopathic traits? A retrospective study

The current study analyzed the relation between recidivism and self-reported psychopathic traits, more specifically the callous-unemotional, impulsivity, and narcissism dimensions of the psychopathy construct. The Antisocial Process Screening Device – Self-Report (APSD-SR) and other self- report instruments independently measuring the three different dimensions of psychopathy (that is, Inventory of Callous-Unemotional Traits, Barratt Impulsiveness Scale-11, Narcissistic Personality-13) were completed by a sample of incarcerated male juvenile offenders (N = 244) who were retrospectively classified as recidivists versus non-recidivists. The only statistically significant relation found between recidivism and self-reported psychopathic traits after controlling for age and socioeconomic status was with the impulsivity dimension of the APSD-SR. Additionally, results showed that recidivism was associated with alcohol use but not with drug use or crime seriousness.This study was supported by the Portuguese Foundation for Science and Technology (FCT; Grant SFRH/BPD/86666/2012) with co-financing of the European Social Fund (POPH/FSE), the Portuguese Ministry of Education and Science (MEC), and the PT2020 Partnership Agreement (UID/PSI/01662/2013)

Adaptation of the Basic Empathy Scale among a Portuguese sample of incarcerated juvenile offenders

The main aim of the present study was to examine the psychometric properties of the Basic Empathy Scale (BES) and of its adapted short version among a forensic sample of incarcerated male juvenile offenders (N = 221). The Portuguese validations of the BES and its adapted short version demonstrated good psychometric properties, namely in terms of the two-factor structure, internal consistency, convergent validity, discriminant validity, and concurrent validity that generally justifies its use among this population. Statistically significant associations were found with callous– unemotional traits and social anxiety. Findings are discussed in terms of the use of the BES and its adapted short version with juvenile offenders.This research was supported by the Portuguese Foundation for Science and Technology (FCT) with co-financing of the European Social Fund – POPH/FSE [grant number SFRH/BPD/86666/2012]

Antifungal activity of a novel chromene dimer

The activity on Aspergillus spp. growth and on ochratoxin A production of two novel chromene dimers (3) was evaluated. The results of the bioassays indicate that the chromene dimer 3a inhibited mycelia growth by approximately 50% (EC50) at 140.1 μmol L−1 for A. niger, 384.2 μmol L−1 for A. carbonarius, 69.1 μmol L−1 for A. alliaceus and 559.1 μmol L−1 for A. ochraceus. When applied at concentrations of 2 mmol L−1, 3a totally inhibited the growth of all Aspergillus spp. tested. Furthermore, ochratoxin A production by A. alliaceus was reduced by about 94% with a 200 μmol L−1 solution of this compound. A moderate inhibitory effect was observed for the analogous structure 3b on ochratoxin A production but not in mycelia growth. No inhibition was registered for compounds 2a and 2b, used as synthetic precursors of the dimeric species 3.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/ 11228/2002