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Mutagenicidade e antimutagenicidade dos principais corantes para alimentos  [cached]
ANTUNES Lusania Maria Greggi,ARAúJO Maria Cristina Paiva
Revista de Nutri??o , 2000,
Abstract: Muitos compostos presentes nos alimentos, tanto naturalmente, como adicionados ou produzidos durante o processamento, já foram testados quanto à mutagenicidade ou antimutagenicidade em diferentes sistemas experimentais. O grande número de corantes para alimentos, naturais ou sintéticos, tem levado os pesquisadores a avaliar a mutagenicidade e/ou antimutagenicidade desses compostos. Alguns corantes sintéticos apresentaram potencial mutagênico e seu uso foi proibido em alguns países. Muitos corantes naturais testados apresentaram potencial antimutagênico em pelo menos um sistema-teste, entretanto, isto n o quer dizer que os corantes naturais s o inócuos. O corante natural curcumina, por exemplo, apresentou potencial antimutagênico nos testes in vivo e foi mutagênico nos testes in vitro. Este paradoxo ressalta a importancia de uma avalia o criteriosa e ampla na avalia o da possível atividade mutagênica e/ou antimutagênica dos corantes.
Peritonitis due to Rhizobium radiobacter  [PDF]
Raquel Marta,Catarina Damaso,José Esteves da Silva,Margarida Almeida
Einstein (S?o Paulo) , 2011,
Abstract: Rhizobium radiobacter (Agrobacterium radiobacter) is an aerobicGram-negative rod belonging to Agrobacterium genus, a groupof phytopathogenic bacteria present in the soil that has beenimplicated in human opportunistic infections. We report a clinicalcase of bacterial peritonitis in a 5-year-old child with chronic renaldisease in peritoneal dialysis, who had a history of direct soilcontact identified. The infection was treated with ceftazidime andpiperaciline+tazobactam without relapses or the need to remove theperitoneal dialysis catheter.
Mutagenicidade e antimutagenicidade dos principais corantes para alimentos
ANTUNES, Lusania Maria Greggi;ARAúJO, Maria Cristina Paiva;
Revista de Nutri??o , 2000, DOI: 10.1590/S1415-52732000000200002
Abstract: many compounds present in foods, whether natural or added or produced during processing, have already been tested for mutagenicity or antimutagenicity in different experimental systems. the great number of food colorings available, both natural and synthetic, has led researchers to assess the mutagenicity and/or antimutagenicity of these compounds. some synthetic colorings have mutagenic potential and their use has been forbidden in some countries. many natural colorings tested have antimutagenic potential in at least one test system, but this does not mean that natural dyes are innocuous. the natural coloring curcumin, for example, showed antimutagenic potential in in vivo tests but was mutagenic in in vitro tests. this paradox emphasizes the importance of careful assessment and wide investigation into the possible mutagenic and/or antimutagenic activity of food colorings.
Catheter associated bloodstream infection caused by R. radiobacter  [cached]
Sood S,Nerurkar V,Malvankar S
Indian Journal of Medical Microbiology , 2010,
Abstract: Rhizobium radiobacter is a gram negative bacillus that is infrequently recognized in clinical specimens but is emerging as an opportunistic human pathogen. Infections due to Rhizobium radiobacter are strongly related to the presence of foreign plastic material and effective treatment often requires removal of the device. We report a case of R. radiobacter bloodstream infection associated with a central venous catheter which was easily controlled by antimicrobial treatment and did not require removal of intravascular device. To the best of our knowledge, this is the first case report from India implicating R. radiobacter as a cause of human infection.
Ausência de mutagenicidade e antimutagenicidade do extrato obtido das flores do ipê roxo [Tabebuia impetiginosa (Mart. ex DC.) Standl.]
Louren?o, J.A.;Pitangui, C.P.;Jord?o, A.A.;Vannucchi, H.;Cecchi, A.O.;
Revista Brasileira de Plantas Medicinais , 2010, DOI: 10.1590/S1516-05722010000400003
Abstract: t. impetiginosa, known as "ipê-roxo", is a plant native to tropical rain forests of central and south americas. chemical compounds obtained from its bark have shown anti-inflammatory, antifungal and antibacterial therapeutic effect. however, due to the lack of data in the literature, little is known about the effects of its flower extract. thus, the aim of this study was to evaluate the mutagenic and antimutagenic potential of the extract obtained from t. impetiginosa flowers at three different concentrations (100, 300 and 500 mg kg-1 p.c.) by the micronucleus test. for the mutagenicity test, doxorubicin (dxr, 90 mg kg-1 p.c.) was used as dna-damage inducer, while for the antimutagenicity test, treatments with the extract were performed simultaneously with this chemical agent. the peripheral blood of animals was collected 24 hours after the treatments. the frequency of polychromatic erythrocytes (pces) in 400 erythrocytes/animal was compared among the different groups and showed no extract cytotoxicity. as regards the frequency of micronuclei in pces (pcemns), there were no significant differences between the groups treated with different concentrations of extract and the negative control. similarly, all groups of animals that received the simultaneous extract treatments (100, 300 or 500 mg kg-1 p.c.) with dxr showed very similar values of pcemns when compared with the data observed for the group of animals that received dxr alone. these results indicate no mutagenic and antimutagenic effect of the extract obtained from t. impetiginosa flowers in the testing system in vivo.
First Report of Tumorigenic Agrobacterium radiobacter on Raspberry in Serbia
Svetlana Milija?evi?,Veljko Gavrilovi?,Svetlana ?ivkovi?,Nenad Trkulja
Pesticidi i Fitomedicina , 2007,
Abstract: During the spring of 2003, gall symptoms on the roots and crowns of young raspberry plants cv. Vilamette were observed near Valjevo. Phytopathogenic bacteria were isolated from diseased plant samples. Based on the pathogenic, morphological, differential biochemicaland physiological characteristics, the isolated strains were identified as tumorigenic Agrobacterium radiobacter (biovar 1 Agrobacterium). In order to confirm the identity of isolated strains by polymerase chain reaction (PCR) primers complementary to tms2 genelocated on the Ti plasmid were used. In the first PCR protocol using a tms2F1 + tms2R2 primer pair, 617 bp products specific for tumorigenic Agrobacterium strains were amplified. The second PCR protocol, using a tms2F1 + tms2B primer pair, amplified the expected 458 bp products. On the basis of multiplex PCR with primers complementary to chromosomal gene coding for 23S rRNA, the isolated strains were classified as biovar 1 Agrobacterium (A. radiobacter). This is the first report of tumorigenic A. radiobacter on raspberry in Serbia.
In vitro and in vivo toxicity studies of Agrobacterium radiobacter k84 biopolymer (ARB) Estudos in vitro e in vivo de toxicidade de biopolímero de Agrobacterium radiobacter k84 (ARB)  [cached]
Caroline Maria Calliari,Marciane Magnani,Alexandre Ykuio Saito,Pedro Sebasti?o Dionízio Filho
Semina : Ciências Agrárias , 2011,
Abstract: Sugar cane molasses is a cheaper carbon source alternative than glucose traditionally used in fermentation processes. In the present study a biopolymer soluble from Agrobacterium radiobacter k84 (ARB) was obtained by fermentation using sugar cane molasses as a carbon source in a process with yield of 10.0 g.L-1. The ARB is composed by minerals (40%), carbohydrate (35%) and protein (15%). In vitro test of the cytotoxic effect of ARB at concentrations 2.5 mg/mL, 5.0 mg/mL and 10.0 mg/mL in LLC MK2 (Rhesus Monkey Kidney) cells revealed a 50% cytotoxic concentration (CC50) of 9.32 mg/mL. In a 30-day in vivo oral toxicity study, Swiss mice were administered ARB by gavage at 5 mg/mL, 15 mg/mL, 50 mg/mL and 150 mg/mL (approximately 25 mg/kg/day, 75 mg/kg/day, 250 mg/kg/day and 750 mg/kg/day). The results did not present any hematological or histopathological signs of adverse effects, leading us to define the no observed adverse effect level (NOAEL) as 150 mg/mL (approximately 750 mg/kg/day). O mela o de cana-de-a úcar é uma fonte de carbono alternativa de menor custo que a glicose tradicionalmente utilizada em processos fermentativos. No presente estudo, um biopolímero solúvel de Agrobacterium radiobacter k84 (ARB) foi obtido por fermenta o utilizando mela o de cana de a úcar como fonte de carbono em um processo com rendimento de 10,0 g.L-1. O ARB é composto de minerais (40%), carboidratos (35%) e proteínas (15%). O teste do efeito citotóxico do ARB in vitro nas concentra es de 2,5 mg/mL, 5,0 mg/mL e 10,0 mg/mL em células LLC MK2 (Rim de Macaco Rhesus) revelou uma concentra o citotóxica 50% (CC50) de 9,32 mg/mL. Em estudo in vivo de toxicidade oral durante 30 dias, camundongos Swiss receberam por gavagem solu es de ARB nas concentra es de 5 mg/mL, 15 mg/mL, 50 mg/mL e 150 mg/mL (aproximadamente 25 mg/kg/dia, 75 mg/kg/dia, 250 mg/ kg/dia e 750 mg/kg/dia). Os resultados n o apresentaram sinais hematológicos ou histopatológicos de efeitos adversos, levando a definir a dose sem efeito adverso observado (NOAEL) como 150 mg/mL (aproximadamente 750 mg/kg/dia).
Avalia??o de mutagenicidade e antimutagenicidade de diferentes fra??es de Pterogyne nitens (Leguminosae), utilizando ensaio de micronúcleo em Tradescantia pallida
Ferreira, Fernanda G.;Regasini, Luis O.;Oliveira, Aline M. de;Campos, Juliana A. D. B.;Silva, Dulce H. S.;Cavalheiro, Alberto J.;Santos, Raquel A. dos;Bassi, Carmen L.;Bolzani, Vanderlan da S.;Soares, Christiane P.;
Revista Brasileira de Farmacognosia , 2009, DOI: 10.1590/S0102-695X2009000100014
Abstract: pterogyne nitens (fabaceae-caesalpinioideae) is a tree native to south american, where it is used in folk treatment of ascaridiasis. recently, we have been describing the mutagenic effect of the ethanol extract of leaves of p. nitens. thus, the present study aimed at evaluating the mutagenic potential of the ethyl acetate (etoac), n- butanol (buoh) and hydroalcoholic (ha) fractions. when the mutagenic effect was observed only in the highest tested concentrations, the antimutagenic activity was also evaluated. both mutagenic and antimutagenic assays were performed using t. pallida micronuclei assay. mutagenicity was observed between different concentrations of the p nitens fractions, etoac (0.460 mg/ml), buoh (0.142, 0.285, 0.570 and 1.14 mg/ml) and ha (0.050, 0.100, 0.200 and 0.400 mg/ml). whereas the mutagenic effect of the etoac fraction was observed in the highest concentration (0.460 mg/ml), its antimutagenic potential was evaluated. the 0.115 and 0.230 mg/ml concentrations of the etoac fraction demonstrated antimutagenic activity. based on the results of the present study we can conclude that some p. nitens fractions (buoh and ha) demonstrated mutagenic effects whereas the etoac fraction shown low mutagenicity and amtimutagenicity in the two higher concentrations. those results stimulate the studies with p. nitens, which possess spread geographic distribution and it is still low studied.
Modeling of D-Hydantoinase Production by Agrobacterium radiobacter in a Batch System  [PDF]
M. Annamalai,Mukesh Doble
Journal of Applied Sciences , 2007,
Abstract: Mathematical modeling of hydantoinase production system from microbial sources, which would help to understand the mechanism of the process, has not been attempted earlier. This paper tries to model five state variables (biomass, substrate, product (D-hydantoinase), Oxygen Uptake Rate (OUR) and carbon dioxide production rate (CPR)) for three carbon sources namely glucose, glycerol and maltose in the production of D-hydantoinase using Agrobacterium radiobacter as source. Several models were tested to fit the aerobic batch experimental data from a 3 L bioreactor. The best fitting model consisted of (a) biomass growth non-linearly dependent on substrate concentration, (b) product formation rate following exponential form of product inhibition and (c) OUR following positive regulation by substrate. D-hydantoinase production in maltose experiences minimal lag phase and stronger product inhibition when compared to glycerol. Maltose showed higher biomass yield (0.25) and specific D-hydantoinase production (27.44 U mg-1) compared to glycerol whose values are 0.18 and 21.97 U mg-1, respectively.
Patogénesis de Listeria monocytogenes, microorganismo zoonotico emergente
Kirvis Torres,Sara Sierra,Raúl Poutou,Ana Carrascal
Revista MVZ Córdoba , 2005,
Abstract: Listeria monocytogenes además de ser un paradigma para la investigación inmunológica se ha convertidoen sistema modelo apropiado para el análisis de los mecanismos moleculares del parasitismo intracelularde otras bacterias. Investigadores en el área de la inmunología se interesaron en este microorganismocuando se reconoció el riesgo que representaba para la salud pública y la seguridad en la industria dealimentos. Desde mediados de los a os 80’s se ha investigado la biología molecular de los marcadores devirulencia de este microorganismo, la biología celular de las interacciones de los marcadores de virulenciacon los receptores de la célula hospedero, el citoesqueleto, las vías de transducción de se ales y losmecanismos de inmunidad mediada por células del hospedero. El propósito de esta revisión es describiralgunas características taxonómicas y filogenéticas de Listeria monocytogenes , la incidencia humana yanimal de varios serotipos, la fisiopatología de la infección , modelos animales y de cultivo celular utilizadospara estudios de virulencia, las poblaciones de riesgo, manifestaciones clínicas de listeriosis humana yanimal, el tratamiento, la organización genética y evolución de los determinantes de virulencia, losmecanismos empleados para interactuar con la célula hospedera, y los mecanismos para escapar de losprocesos de muerte celular y pasar de una célula infectada a otra. La información recopilada resulta degran importancia para el personal de salud, industria, consumidores y población de riesgo; razón por lacual Listeria monocytogenes es un patógeno que representa una amenaza para la salud pública mundial.
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