43 research outputs found
effect of temperature on production of ochratoxin a by aspergillus niger in orange juice
This challenging study was carried out to evaluate the temporal production of ochratoxin A (OTA) byAspergillus nigerATCC 16404 and wild typeA. nigerAM at different temperatures in fresh squeezed orange juice (Citrus sinensis[L.] Osbeck cv Tarocco). Each strain, inoculated into the filtered orange juice, was incubated at 4°C, 20°C, and 26°C for 28 days. In the juice, at 26°C and 20°C, the concentration ofA. nigerATCC 16404 increased by more than 2 log10up to the 21st day. At 4°C it remained constant. The microbial load ofA. nigerAM decreased at all temperatures. At 26°C, the maximum OTA accumulation found was 3.44 ng/mL on the 21st day forA. nigerATCC 16404 and 8. 44 ng/mL on the 7th day forA. nigerAM. The OTA synthesis seemed to be an intrinsic strain-dependent mechanism.A. nigerATCC 16404 produced OTA in accordance with the higher temperatures and the biomass concentrations, whereasA. nigerAM produced the toxin at all temperatures regardless of its biomass. These results showed that fresh orange juice contaminated withAspergillus nigeraggregate strains may contain OTA levels
Efficacy of a Fixed Combination of Tetracycline, Chloramphenicol, and Colistimethate Sodium for Treatment of Candida albicans Keratitis
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Functionalization of Polyhydroxyalkanoates (PHA)-Based Bioplastic with Phloretin for Active Food Packaging: Characterization of Its Mechanical, Antioxidant, and Antimicrobial Activities
: The formulation of eco-friendly biodegradable packaging has received great attention during the last decades as an alternative to traditional widespread petroleum-based food packaging. With this aim, we designed and tested the properties of polyhydroxyalkanoates (PHA)-based bioplastics functionalized with phloretin as far as antioxidant, antimicrobial, and morpho-mechanic features are concerned. Mechanical and hydrophilicity features investigations revealed a mild influence of phloretin on the novel materials as a function of the concentration utilized (5, 7.5, 10, and 20 mg) with variation in FTIR e RAMAN spectra as well as in mechanical properties. Functionalization of PHA-based polymers resulted in the acquisition of the antioxidant activity (in a dose-dependent manner) tested by DPPH, TEAC, FRAR, and chelating assays, and in a decrease in the growth of food-borne pathogens (Listeria monocytogenes ATCC 13932). Finally, apple samples were packed in the functionalized PHA films for 24, 48, and 72 h, observing remarkable effects on the stabilization of apple samples. The results open the possibility to utilize phloretin as a functionalizing agent for bioplastic formulation, especially in relation to food packaging
Finalised dependability framework and evaluation results
The ambitious aim of CONNECT is to achieve universal interoperability between heterogeneous Networked Systems by means of on-the-fly synthesis of the CONNECTors through which they communicate. The goal of WP5 within CONNECT is to ensure that the non-functional properties required at each side of the connection going to be established are fulfilled, including dependability, performance, security and trust, or, in one overarching term, CONNECTability. To model such properties, we have introduced the CPMM meta-model which establishes the relevant concepts and their relations, and also includes a Complex Event language to express the behaviour associated with the specified properties. Along the four years of project duration, we have developed approaches for assuring CONNECTability both at synthesis time and at run-time. Within CONNECT architecture, these approaches are supported via the following enablers: the Dependability and Performance analysis Enabler, which is implemented in a modular architecture supporting stochastic verification and state-based analysis. Dependability and performance analysis also relies on approaches for incremental verification to adjust CONNECTor parameters at run-time; the Security Enabler, which implements a Security-by-Contract-with-Trust framework to guarantee the expected security policies and enforce them accordingly to the level of trust; the Trust Manager that implements a model-based approach to mediate between different trust models and ensure interoperable trust management. The enablers have been integrated within the CONNECT architecture, and in particular can interact with the CONNECT event-based monitoring enabler (GLIMPSE Enabler released within WP4) for run-time analysis and verification. To support a Model-driven approach in the interaction with the monitor, we have developed a CPMM editor and a translator from CPMM to the GLIMPSE native language (Drools). In this document that is the final deliverable from WP5 we first present the latest advances in the fourth year concerning CPMM, Dependability&Performance Analysis, Incremental Verification and Security. Then, we make an overall summary of main achievements for the whole project lifecycle. In appendix we also include some relevant articles specifically focussing on CONNECTability that have been prepared in the last period
Avaliação do efeito do eucaliptol nas convulsões induzidas por pentilenotetrazol em camundongos
The developmental process of epilepsies involves diverse mechanisms that culminate in the hyperactivity of a population of neurons, resulting in a pattern of repeated and rhythmic depolarizations. Antiepileptic drugs act by increasing GABAergic neurotransmission, reducing the effects of glutamate, or blocking ion channels, and are endowed with serious adverse effects that make it difficult for patients to adhere to treatment. This fact has encouraged the search for compounds of natural origin with potential anticonvulsant effect. Thus, the present study aimed to evaluate the effect of eucalyptol in seizures induced by pentylenetetrazole (PTZ). For this, male Swiss mice, orally treated with monotrepene, were used. The first protocol evaluated the toxicity and the estimated LD50 of the compound. Based on the value of LD50, the doses of terpene used in the behavioral and neurochemical tests were selected. For the behavioral tests, groups of mice were pretreated with saline (10 mL/kg, vol), diazepam (2 mg/kg, ip) and eucalyptol (100, 200 and 400 mg/kg, vol) and then with pentylenetetrazole 80 mg/kg, ip) and evaluated for the following parameters: seizure intensity, latency for first seizure and time of death. For neurochemical tests, groups of mice were pretreated with saline (10 mL/kg, v.o.) and eucalyptol (400 mg/kg, i.p.) and subsequently with pentylenetetrazole (80 mg/kg, i.p.); The determination of the concentration of neurotransmitters (monoamines - dopamine, noradrenaline and serotonin) and oxidative stress markers (nitrite and thiobarbituric acid reactive substances - TBARs) were the parameters evaluated. The results were analyzed by ANOVA or Kruskal-Wallis, followed by Student-Newman-Keuls, and Dunns, respectively. Values of p <0.05 were considered significant. The results showed that oral administration of eucalyptol had low toxicity and the estimated LD50 was greater than 2000 mg / kg. In the PTZ-induced seizure test, only the higher dose of monoterpene (400 mg/kg) significantly reduced seizure intensity by 60%, increased latency for onset of the first seizure by 85% and time of death of the animals in 75% in relation to the control. Similarly, treatment with eucalyptol (400 mg/kg) significantly reduced the concentration of noradrenaline, dopamine and serotonin by 50%, 33% and 70%, respectively, in relation to the PTZ-treated group (80 mg/kg). In addition, treatment with eucalyptol (400 mg/kg) significantly reduced the concentration of TBARs by 33%, but not nitrite, relative to the PTZ treated group (80 mg/kg). Taken together, the results show that the monoterpene studied has low oral toxicity and an important anticonvulsant effect, since its administration is capable of attenuating the convulsions chemically induced by pentylenetetrazol with consequent reduction of the concentration of monoamines and the reactive substances of thiobarbituric acid, elements whose increase is associated with the epileptogenesis phenomenon.O processo de desenvolvimento das epilepsias envolve mecanismos diversos que culminam na hiperatividade de uma população de neurônios, resultando em um padrão de despolarizações repetidas e rítmicas. Os fármacos antiepilépticos agem através do aumento da neurotransmissão GABAérgica, da redução dos efeitos do glutamato, ou do bloqueio de canais iônicos, sendo dotados de efeitos adversos sérios que dificultam a adesão do paciente ao tratamento. Este fato tem incentivado a busca por compostos de origem natural com potencial efeito anticonvulsivante. Desta forma, o presente trabalho teve como objetivo avaliar o efeito do eucaliptol nas convulsões induzidas por pentilenotetrazol (PTZ). Para tanto, foram utilizados camundongos Swiss machos, tratados oralmente com o monotrepeno. O primeiro protocolo realizado avaliou a toxicidade e a DL50 estimada do composto. Com base no valor da DL50, foram selecionadas as doses do terpeno utilizadas nos testes comportamentais e neuroqímicos. Para os testes comportamentais, grupos de camundongos foram previamente tratados com salina (10 mL/kg, v.o.), diazepam (2 mg/kg, i.p.) e eucaliptol (100, 200 e 400 mg/kg, v.o.) e posteriormente com pentilenotetrazol (80 mg/kg, i.p.) e avaliados quanto aos seguintes parâmetros: intensidade das convulsões, latência para primeira convulsão e tempo de morte. Para os testes neuroquímicos, grupos de camundongos foram previamente tratados com salina (10 mL/kg, v.o.) e eucaliptol (400 mg/kg, i.p.) e posteriormente com pentilenotetrazol (80 mg/kg, i.p.); a determinação da concentração de neurotransmissores (monoaminas – dopamina, noradrenalina e serotonina) e dos marcadores de estresse oxidativo (nitrito e substâncias reativas do ácido tiobarbitúrico – TBARs) foram os parâmetros avaliados. Os resultados foram analisados por ANOVA ou Kruskal-Wallis, seguido dos testes de Student-Newman-Keuls, e Dunns, respectivamente. Foram considerados significativos os valores de p < 0,05. Os resultados mostraram que a administração oral do eucaliptol apresentou baixa toxicidade e a DL50 estimada foi superior a 2000 mg/kg. No teste das convulsões induzidas por PTZ apenas a dose maior do monoterpeno (400 mg/kg) reduziu de forma significativa a intensidade das convulsões em 60%, aumentou a latência para aparecimento da primeira convulsão em 85% e o tempo de morte dos animais em 75% em relação ao controle. De forma semelhante, o tratamento com eucaliptol (400 mg/kg) reduziu de forma significativa a concentração de noradrenalina, dopamina e serotonina, em 50%, 33% e 70%, respectivamente, em relação ao grupo tratado com PTZ (80 mg/kg). Além disso, o tratamento com eucaliptol (400 mg/kg) reduziu de forma significativa a concentração de TBARs em 33%, mas não de nitrito, em relação ao grupo tratado com PTZ (80 mg/kg). Tomados em conjunto, os resultados mostram que o monoterpeno estudado apresenta baixa toxicidade oral e importante efeito anticonvulsivante, visto que sua administração é capaz de atenuar as convulsões quimicamente induzidas por pentilenotetrazol com consequente redução da concentração de monoaminas e das substâncias reativas do ácido tiobarbitúrico, elementos cujo aumento está associado ao fenômeno da epileptogênese
Consolidated dependability framework
The aim of CONNECT is to achieve universal interoperability between heterogeneous Networked Systems. For this, the non-functional properties required at each side of the connection going to be established, which we refer to by the one inclusive term "CONNECTability", must be fulfilled. In Deliverable D5.1 we conceived the conceptual models at the foundation of CONNECTability. In D5.2 we then presented a first version of the approaches and of their respective enablers that we developed for assuring CONNECTability both at synthesis time and at run-time. In this deliverables, we present the advancements and contributions achieved in the third year, which include: - a refinement of the CONNECT Property Meta-Model, with a preliminary implementation of a Model-to-Code translator; - an enhanced implementation of the Dependability&Performance analysis Enabler, supporting stochastic verification and state-based analysis, that is enriched with mechanisms for providing feedback to the Synthesis enabler based on monitor's run-time observations; - a fully running version of the Security Enabler, following the Security-by-Contract-with-Trust methodology, for the monitoring and enforcement of CONNECT related security policies; - a complete (XML) definition of the Trust Model Description Language, an editor and the corresponding implementation of supporting tools to be integrated into the Trust Management Enabler
Antimicrobial additives for poly(lactic acid) materials and their applications: current state and perspectives
Poly(lactic acid)-based antimicrobial materials received considerable attention as promising systems to control microbial growth. The remarkable physicochemical properties of PLA such as renewability, biodegradability, and US Food and Drug Administration (FDA) approval for clinical use open up interesting perspectives for application in food packaging and biomedical materials. Nowadays, there is an increasing consumer demands for fresh, high-quality, and natural foods packaged with environmentally friendly materials that prolong the shelf life. The incorporation of antimicrobial agents into PLA-based polymers is likely to lead to the next generation of packaging materials. The development of antimicrobial PLA materials as a delivery system or coating for biomedical devices is also advantageous in order to reduce possible dose-dependent side effects and limit the phenomena of antibiotic resistance. This mini-review summarizes the most recent advances made in antimicrobial PLA-based polymers including their preparation, biocidal action, and applications. It also highlights the potential of PLA systems as efficient stabilizers-carriers of various kinds of antimicrobial additives including essential oils and other natural compounds, active particles and nanoparticles, and conventional and synthetic molecules
Activity of Colloidal Silver Solution against Microorganisms Implicated in Ocular Infections
Endophthalmitis most likely originates from both planktonic bacteria suspended in the tear film and bacteria adherent to the conjunctiva and the eyelid. This study aimed to expand the research on the effectiveness of a colloidal silver solution (Silverix®) against ocular microorganisms. The activity of Silverix® was evaluated against methicillin-resistant Staphylococcus aureus, S. epidermidis, ofloxacin-resistant Pseudomonas aeruginosa, and Candida albicans strains, previously characterized for their antibiotic resistance and biofilm-forming capabilities. The microbial killing was estimated at various times in the presence and absence of colloidal silver solution against planktonic and biofilm-embedded cells. The results documented the efficacy of Silverix® on planktonic cells of S. aureus and S. epidermidis (2.49–2.87 Log CFU/mL reduction) and P. aeruginosa strains (3–4.35 Log CFU/mL reduction). On the contrary, C. albicans showed mild susceptibility. Regarding early biofilm, the ocular isolates were harder to kill (2–2.6 Log CFU/mL reduction) than the reference strains, whereas a similar decrease (3.1 Log CFU/mL reduction) was estimated for P. aeruginosa strains. The light microscope images of biofilms treated with colloidal solution confirmed the ability of Silverix® to destroy the biofilm
Activity of Colloidal Silver Solution against Microorganisms Implicated in Ocular Infections
Endophthalmitis most likely originates from both planktonic bacteria suspended in the tear film and bacteria adherent to the conjunctiva and the eyelid. This study aimed to expand the research on the effectiveness of a colloidal silver solution (Silverix®) against ocular microorganisms. The activity of Silverix® was evaluated against methicillin-resistant Staphylococcus aureus, S. epidermidis, ofloxacin-resistant Pseudomonas aeruginosa, and Candida albicans strains, previously characterized for their antibiotic resistance and biofilm-forming capabilities. The microbial killing was estimated at various times in the presence and absence of colloidal silver solution against planktonic and biofilm-embedded cells. The results documented the efficacy of Silverix® on planktonic cells of S. aureus and S. epidermidis (2.49–2.87 Log CFU/mL reduction) and P. aeruginosa strains (3–4.35 Log CFU/mL reduction). On the contrary, C. albicans showed mild susceptibility. Regarding early biofilm, the ocular isolates were harder to kill (2–2.6 Log CFU/mL reduction) than the reference strains, whereas a similar decrease (3.1 Log CFU/mL reduction) was estimated for P. aeruginosa strains. The light microscope images of biofilms treated with colloidal solution confirmed the ability of Silverix® to destroy the biofilm