Thesis--Wisconsin. / Includes bibliographical references (leaves 70-76).

Universiẗat, Diss., 2004--Kiel.

Im Gegensatz zu den renalen Transportmechanismen von OTA ist die gastrointestinale Absorption dieses Mykotoxins weitaus weniger untersucht worden. Die bisherigen Untersuchungen deuten darauf hin, dass OTA aus der Nahrung über einfache passive Diffusion der nicht-dissoziiert vorliegenden Form aufgenommen wird. Weitere Informationen zur Absorption von OTA aus dem Verdauungstrakt in vivo, insbesondere zur Beteiligung von Transportsystemen, wie sie in der Niere beobachtet wurden, liegen nicht vor. In der vorliegenden Arbeit sollte daher mittels einer in situ-Perfusionsmethode an Ratten die Aufnahme von OTA aus dem Darmlumen ins Blut untersucht werden. Zunächst konnte, wie es auch schon in früheren Arbeiten beobachtet worden war, gezeigt werden, dass im proximalen Jejunum im Vergleich zum mittleren und distalen Abschnitt des Jejunums eine höhere Aufnahme von OTA stattfand. Des Weiteren trat eine deutliche Abhängigkeit vom luminalen pH-Wert in der OTA-Absorption auf, wobei signifikant mehr OTA aufgenommen wurde, je niedriger der luminale pH-Wert war. Ein saturabler Transportmechanismus konnte in dem untersuchten Konzentrationsbereich nicht beobachtet werden. Weiterhin traten keine signikanten Unterschiede bei einem Zusatz von Glucose im Vergleich zur Kontrollgruppe auf, was den parazellulären Weg für die Absorption von OTA als unwahrscheinlich erscheinen lässt. Auch Substrate verschiedener Transportsysteme (Glycylsarcosin, Aspartam, Phenyalalanin, Leucin und Taurocholat) zeigten keinen statistisch signifikanten Einfluss auf die OTA-Absorption. Die Bindung von OTA an Proteine verhinderte die intestinale OTA-Absorption deutlich. Aufgrund der eigenen Befunde und der Daten aus der Literatur scheint die intestinale OTA-Absorption hauptsächlich transzellulär über einfache Diffusion der nicht-dissoziierten Form zu erfolgen. Es bestehen somit deutlich Unterschiede zur renalen Absorption von OTA.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-08-05T12:02:02Z No. of bitstreams: 1 2010 - Cesar Daniel Kruger.pdf: 4305938 bytes, checksum: b0a2db06d6603a1f3b55d1c934d1f418 (MD5) / Made available in DSpace on 2016-08-05T12:02:02Z (GMT). No. of bitstreams: 1 2010 - Cesar Daniel Kruger.pdf: 4305938 bytes, checksum: b0a2db06d6603a1f3b55d1c934d1f418 (MD5) Previous issue date: 2010-02-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior, CAPES / Interest in fungi and the mycotoxins is enormous, not only from the scientific point of view, but also in the economic outlook. There are many problems arising from the farmer to the consumer. Low yields, deteriorating levels in commercial husbandry of animals and disease in them, changes in food, loss of sensory and nutritional characteristics, increased costs resulting from the prevention and treatment of decontamination are among some of the disorders generated by the presence of fungi and their matab?litos. Ochratoxin A occupies every day a major role in the setting of Mycotoxicology due to its importance. Many efforts have been undertaken to define the global situation of occurrence of this mycotoxin. This study focused on a set in specific areas the occurrence of this mycotoxin, which not long ago was ignored in the setting of contaminants in Brazil as well as putting into practice the methods of detection of OTA in pig serum. We collected 400 samples of blood serum from pig slaughterhouses in four different states. These samples were processed and subjected to techniques for determining liquid chromatography with high efficiency to determine concentrations of the toxin in the study. RESULTS: The mean concentration of ochratoxin A in pig blood serum samples with levels above the limit of detection was 23.729 ?g/L. CONCLUSIONS: Ochratoxin A is present in the pork produced in Brazil. All the samples surveyed were above the limit of detection and quantification. The colder climate favors the development of ochratoxin A, demonstrated the highest level of positive samples with limits above 5 ?g/L in the State of Santa Catarina (52%). The state of Mato Grosso showed the highest number of positive samples for ochratoxin A above the limit detectable by the technique used (69%). The State of Bahia showed the greatest number of samples below the detectable limit (64%). / O interesse pelos fungos e pelas micotoxinas ? enorme, n?o s? do ponto de vista cient?fico, como tamb?m sob a perspectiva econ?mica. S?o muitos os problemas gerados desde o agricultor at? o consumidor final. Baixos rendimentos da colheita, deterioramento de n?veis zoot?cnicos na produ??o comercial de animais e doen?a nos mesmos, altera??es nos alimentos, perdas de caracter?sticas sensoriais e nutricionais, aumento dos custos derivados da preven??o e do tratamento descontaminante est?o entre alguns dos transtornos gerados pela presen?a dos fungos e seus matab?litos. A ocratoxina A ocupa a cada dia um papel de destaque no cen?rio da micotoxicologia devido a sua import?ncia. Muitos esfor?os t?m sido empreendidos para se definir a situa??o mundial da ocorr?ncia desta micotoxina. Este trabalho teve como foco principal definir em algumas ?reas espec?ficas a ocorr?ncia desta micotoxina, que h? pouco tempo atr?s era ignorada dentro do cen?rio dos contaminantes nos produtos brasileiros, al?m de colocar em pr?tica a metodologia de detec??o de OTA em soro su?no. Foram coletadas 400 amostras de soro sangu?neo su?no em diferentes matadouros de quatro estados brasileiros. Estas amostras foram processadas e submetidas a t?cnicas de determina??o por cromatografia l?quida de alta efici?ncia para se determinar suas concentra??es da toxina em estudo. RESULTADOS: A concentra??o m?dia de ocratoxina A no soro sangu?neo su?no das amostras com n?veis acima do limite de detec??o foi de 23,729 ?g/L. CONCLUS?ES: A ocratoxina A est? presente no su?no produzido no Brasil. Todos os Estados pesquisados apresentaram amostras acima do limite de detec??o e quantifica??o. O clima mais frio favorece o aparecimento de ocratoxina A, demonstrado no maior n?vel de amostras positivas com limites acima de 5 ?g/L no Estado de Santa Catarina (52%). O Estado de Mato Grosso apresentou o maior n?mero de amostras positivas para ocratoxina A acima do limite detect?vel pela t?cnica utilizada (69%). O Estado da Bahia foi o que apresentou maior quantidade de amostras abaixo do limite detect?vel (64%).

The use of near ambient air drying for the preservation of wheat stored in granaries is common in Western Canada. Guidelines have been developed to assist farmers in selecting appropriate drying methods. During this process the top layer of wheat can remain at moisture contents (m.c.) greater than the safe storage limit, 14.5% wet bulb (wb), for up to 12 weeks. This study tested the effects of this drying procedure on the development of ochratoxin A (OTA) using 1 m3 bulks of durum wheat at 18% m.c. (wb) contained within steel bins inside a Weather Simulation Lab. In a second study using 20 L volumes of wheat at a m.c. of 20% (wb) within an environmental growth chamber potential development of OTA was also evaluated. The wheat was exposed to two treatments, airflow and no airflow, for a period of 12 weeks under conditions of high relative humidity (greater than 80%) and typical Manitoba fall temperatures. The storage quality parameters of germination, fat acidity value, and presence of OTA were measured weekly. It was found that high moisture wheat stored under all treatment conditions showed a rapid decrease in germination and increase in fat acidity value over time, with no significant difference between the treatments. Under the tested conditions the development of ochratoxin A was not detected in significant quantities in the 1 m3 bulks of grain but was detected in the smaller 20 L bulks.

The use of near ambient air drying for the preservation of wheat stored in granaries is common in Western Canada. Guidelines have been developed to assist farmers in selecting appropriate drying methods. During this process the top layer of wheat can remain at moisture contents (m.c.) greater than the safe storage limit, 14.5% wet bulb (wb), for up to 12 weeks. This study tested the effects of this drying procedure on the development of ochratoxin A (OTA) using 1 m3 bulks of durum wheat at 18% m.c. (wb) contained within steel bins inside a Weather Simulation Lab. In a second study using 20 L volumes of wheat at a m.c. of 20% (wb) within an environmental growth chamber potential development of OTA was also evaluated. The wheat was exposed to two treatments, airflow and no airflow, for a period of 12 weeks under conditions of high relative humidity (greater than 80%) and typical Manitoba fall temperatures. The storage quality parameters of germination, fat acidity value, and presence of OTA were measured weekly. It was found that high moisture wheat stored under all treatment conditions showed a rapid decrease in germination and increase in fat acidity value over time, with no significant difference between the treatments. Under the tested conditions the development of ochratoxin A was not detected in significant quantities in the 1 m3 bulks of grain but was detected in the smaller 20 L bulks.

Konstanz, Univ., Bachelorarb., 2007.

A ocratoxina (OTA) é uma micotoxina que possui propriedades nefrotóxicas, hepatotóxicas, teratogênicas e carcinogênicas. No Brasil, o limite máximo permitido de OTA em vinhos foi estabelecido em 2011 e é 2 μg/L. A ocorrência desta toxina em vinhos está relacionada principalmente à presença de fungos do gênero Aspergillus nas uvas usadas para a vinificação. Deste modo, o objetivo deste estudo foi verificar a influência das etapas de elaboração de vinho Cabernet Sauvignon sobre os níveis de OTA, através de dois diferentes experimentos: (A) vinho elaborado a partir de uvas inoculadas com fungo ocratoxigênico e (B) vinho elaborado com uvas naturalmente contaminadas com OTA. Para os dois experimentos, amostras das etapas mosto, fermentação/maceração, descuba, pós-fermentação, trasfega e maturação foram coletadas em triplicata, durante um período de 5 meses. A OTA foi detectada através da técnica de cromatografia líquida de alta eficiência com detector de fluorescência (CLAE-FL) e o limite de detecção e quantificação foi de 0,06 μg/L e 0,6 μg/L, respectivamente. Durante a vinificação, as etapas que apresentaram maior percentual de redução da toxina foram descuba, pós-fermentação e trasfega. Reduções significativas nos níveis de OTA foram observadas após a conclusão da vinificação. No vinho elaborado com uvas inoculadas com fungo ocratoxigênico observou-se uma redução de 92,6%. Valor similar (92%) foi verificado no vinho produzido com uvas naturalmente contaminadas por OTA. Considerando todo o processo de vinificação, pode-se sugerir que a diminuição dos níveis de OTA foi observada principalmente, devido à adsorção da toxina à parede celular das leveduras. Além disso, a adsorção da toxina aos sólidos em suspensão presentes no vinho durante a elaboração pode ter ocorrido. / The ochratoxin A (OTA) is a mycotoxin with nephrotoxic, hepatotoxic, teratogenic and carcinogenic properties. In Brazil, the permitted maximum limits for the OTA in wines was established in 2011 and is 2 μg/L. The occurence of this toxin in wines is due mainly for presence of fungi from Aspergillus genera in grapes used for winemaking. In this way, the aim of this study was to check the influence of stages of the winemaking process of Cabernet Sauvignon grape on the OTA levels through two different experiments: (A) wine made from grapes inoculated with ochratoxigenic fungi and (B) wine made from grapes naturally contaminated with OTA. For the two experiments, samples of must, fermentation/maceration, drawn-off wine, after fermentation, racking and maturation stages were collected in triplicate, during 5 months. The OTA was detected using high-performance liquid chromatography with fluorecence detector (HPLC-FL) and the limit of detection and limit of quantitation were 0.06 and 0.6 μg/L, respectively. During the winemaking, the stages that show higher toxin reduction were drawn-off wine, after alcoholic fermentation and racking. Significant reductions in OTA levels were observed when winemaking was finished. A reduction of 92.6% was observed in wine made from grapes inoculated with ochratoxigenic fungi. Similar value (92%) was verified in wine made from grapes naturally contaminated with OTA. Considering all winemaking process, we may suggest that the decreasing of OTA levels was observed mainly due to adsorption of the toxin in cell wall of yeast. Furthermore, the adsorption of the toxin in suspended solids present in wine during the winemaking may be occurred.

A ocratoxina (OTA) é uma micotoxina que possui propriedades nefrotóxicas, hepatotóxicas, teratogênicas e carcinogênicas. No Brasil, o limite máximo permitido de OTA em vinhos foi estabelecido em 2011 e é 2 μg/L. A ocorrência desta toxina em vinhos está relacionada principalmente à presença de fungos do gênero Aspergillus nas uvas usadas para a vinificação. Deste modo, o objetivo deste estudo foi verificar a influência das etapas de elaboração de vinho Cabernet Sauvignon sobre os níveis de OTA, através de dois diferentes experimentos: (A) vinho elaborado a partir de uvas inoculadas com fungo ocratoxigênico e (B) vinho elaborado com uvas naturalmente contaminadas com OTA. Para os dois experimentos, amostras das etapas mosto, fermentação/maceração, descuba, pós-fermentação, trasfega e maturação foram coletadas em triplicata, durante um período de 5 meses. A OTA foi detectada através da técnica de cromatografia líquida de alta eficiência com detector de fluorescência (CLAE-FL) e o limite de detecção e quantificação foi de 0,06 μg/L e 0,6 μg/L, respectivamente. Durante a vinificação, as etapas que apresentaram maior percentual de redução da toxina foram descuba, pós-fermentação e trasfega. Reduções significativas nos níveis de OTA foram observadas após a conclusão da vinificação. No vinho elaborado com uvas inoculadas com fungo ocratoxigênico observou-se uma redução de 92,6%. Valor similar (92%) foi verificado no vinho produzido com uvas naturalmente contaminadas por OTA. Considerando todo o processo de vinificação, pode-se sugerir que a diminuição dos níveis de OTA foi observada principalmente, devido à adsorção da toxina à parede celular das leveduras. Além disso, a adsorção da toxina aos sólidos em suspensão presentes no vinho durante a elaboração pode ter ocorrido. / The ochratoxin A (OTA) is a mycotoxin with nephrotoxic, hepatotoxic, teratogenic and carcinogenic properties. In Brazil, the permitted maximum limits for the OTA in wines was established in 2011 and is 2 μg/L. The occurence of this toxin in wines is due mainly for presence of fungi from Aspergillus genera in grapes used for winemaking. In this way, the aim of this study was to check the influence of stages of the winemaking process of Cabernet Sauvignon grape on the OTA levels through two different experiments: (A) wine made from grapes inoculated with ochratoxigenic fungi and (B) wine made from grapes naturally contaminated with OTA. For the two experiments, samples of must, fermentation/maceration, drawn-off wine, after fermentation, racking and maturation stages were collected in triplicate, during 5 months. The OTA was detected using high-performance liquid chromatography with fluorecence detector (HPLC-FL) and the limit of detection and limit of quantitation were 0.06 and 0.6 μg/L, respectively. During the winemaking, the stages that show higher toxin reduction were drawn-off wine, after alcoholic fermentation and racking. Significant reductions in OTA levels were observed when winemaking was finished. A reduction of 92.6% was observed in wine made from grapes inoculated with ochratoxigenic fungi. Similar value (92%) was verified in wine made from grapes naturally contaminated with OTA. Considering all winemaking process, we may suggest that the decreasing of OTA levels was observed mainly due to adsorption of the toxin in cell wall of yeast. Furthermore, the adsorption of the toxin in suspended solids present in wine during the winemaking may be occurred.

A ocratoxina (OTA) é uma micotoxina que possui propriedades nefrotóxicas, hepatotóxicas, teratogênicas e carcinogênicas. No Brasil, o limite máximo permitido de OTA em vinhos foi estabelecido em 2011 e é 2 μg/L. A ocorrência desta toxina em vinhos está relacionada principalmente à presença de fungos do gênero Aspergillus nas uvas usadas para a vinificação. Deste modo, o objetivo deste estudo foi verificar a influência das etapas de elaboração de vinho Cabernet Sauvignon sobre os níveis de OTA, através de dois diferentes experimentos: (A) vinho elaborado a partir de uvas inoculadas com fungo ocratoxigênico e (B) vinho elaborado com uvas naturalmente contaminadas com OTA. Para os dois experimentos, amostras das etapas mosto, fermentação/maceração, descuba, pós-fermentação, trasfega e maturação foram coletadas em triplicata, durante um período de 5 meses. A OTA foi detectada através da técnica de cromatografia líquida de alta eficiência com detector de fluorescência (CLAE-FL) e o limite de detecção e quantificação foi de 0,06 μg/L e 0,6 μg/L, respectivamente. Durante a vinificação, as etapas que apresentaram maior percentual de redução da toxina foram descuba, pós-fermentação e trasfega. Reduções significativas nos níveis de OTA foram observadas após a conclusão da vinificação. No vinho elaborado com uvas inoculadas com fungo ocratoxigênico observou-se uma redução de 92,6%. Valor similar (92%) foi verificado no vinho produzido com uvas naturalmente contaminadas por OTA. Considerando todo o processo de vinificação, pode-se sugerir que a diminuição dos níveis de OTA foi observada principalmente, devido à adsorção da toxina à parede celular das leveduras. Além disso, a adsorção da toxina aos sólidos em suspensão presentes no vinho durante a elaboração pode ter ocorrido. / The ochratoxin A (OTA) is a mycotoxin with nephrotoxic, hepatotoxic, teratogenic and carcinogenic properties. In Brazil, the permitted maximum limits for the OTA in wines was established in 2011 and is 2 μg/L. The occurence of this toxin in wines is due mainly for presence of fungi from Aspergillus genera in grapes used for winemaking. In this way, the aim of this study was to check the influence of stages of the winemaking process of Cabernet Sauvignon grape on the OTA levels through two different experiments: (A) wine made from grapes inoculated with ochratoxigenic fungi and (B) wine made from grapes naturally contaminated with OTA. For the two experiments, samples of must, fermentation/maceration, drawn-off wine, after fermentation, racking and maturation stages were collected in triplicate, during 5 months. The OTA was detected using high-performance liquid chromatography with fluorecence detector (HPLC-FL) and the limit of detection and limit of quantitation were 0.06 and 0.6 μg/L, respectively. During the winemaking, the stages that show higher toxin reduction were drawn-off wine, after alcoholic fermentation and racking. Significant reductions in OTA levels were observed when winemaking was finished. A reduction of 92.6% was observed in wine made from grapes inoculated with ochratoxigenic fungi. Similar value (92%) was verified in wine made from grapes naturally contaminated with OTA. Considering all winemaking process, we may suggest that the decreasing of OTA levels was observed mainly due to adsorption of the toxin in cell wall of yeast. Furthermore, the adsorption of the toxin in suspended solids present in wine during the winemaking may be occurred.