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Alteration of Key Cytokine Levels by Aflatoxin B<sub>1</sub> and T-2 Toxin in Male CD-1 MiceDugyala, Raviprakash R. 01 May 1995 (has links)
Aflatoxin B1 and T-2 toxin are mycotoxins, which produce their immunotoxic effects by affecting nonspecific and acquired immunity in different species. The mechanisms of their immunotoxicity are still obscure. Cytokines are the key signaling molecules during the immune response. In this study, expression of macrophage-produced cytokines Interleukin-lα (IL-lα), tumor necrosis factor (TNF), and IL-6, and lymphocyte-produced cytokines IL-2, interferon y (IFNy), and IL-3 was measured at the mRNA and protein levels, after in vitro activation with mitogens in AFB1-and T-2-toxin-exposed mice.
Significant changes in the organ weights, especially in the mice exposed to a high dose of T-2 toxin, and no effect in AFB1-exposed mice were observed.
ConA-induced production of IL-2, IFNy, and IL-3 mRNA and protein levels in AFB1-exposed mice showed a decrease in low dose groups (significant for IL-2 mRNA), but no change at other doses. However, in T-2-toxin-treated animals, there was a significant induction of IL-2 and IFNy mRNA in high and low doses and of IL-3 mRNA at the medium dose. The protein levels of IL-2 and IFNy did not follow the mRNA levels in high dose and the protein levels of IL-3 were significantly increased in medium and low doses.
LPS-induced IL-lα and TNF mRNA and protein levels in AFB1-exposed mice were suppressed at the high dose while mRNA levels of both cytokines were increased significantly in the low and medium doses. Low and medium doses of AFB1 also significantly decreased IL-lα protein levels and the high dose decreased IL-6 protein. In T-2 toxin-treated mice, no significant difference in mRNA levels of these cytokines was observed but a general pattern of significant suppression of their protein levels (except IL-lα at medium dose) showed that both toxins regulate the cytokine expression differently.
Based on the above discussed results and others, AFB1 may alter cell-mediated immunity by affecting the communication between macrophages and T lymphocytes through inhibiting the macrophage-producing cytokines. T-2 toxin-induced immunosuppression may be due not only to the inhibition of macrophage-producing cytokines, but also to the lack of effector cells to respond to the cytokines (IL-2, IFNy, and IL-3).
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Chemoprotective action of natural products on cultured human epithelial cells exposed to aflatoxin B1Reddy, Lalini January 2005 (has links)
Thesis (D.Tech.: Biotechnology)-Dept. of Biotechnology, Durban Institute of Technology, 2005 xx, 175, [14] leaves : ill. ; 30 cm / Previous studies indicate that a mutation in the non-oncogenic p53 gene is epidemiologically linked to human HCC (Ozturk, 1991; Chan et al., 2003). Hsu et al. (1991) found this link in Chinese, South African and Asian patients and Hollstein et al. (1993) found the same gene mutation in Taiwanese patients. The incidence of these aberrations is reported to be about 20- 50% in HCC’s (Kishimoto et al., 1997). There is sufficient evidence to indicate that carotenoids in addition to their well known antioxidant properties (Paiva and Russel, 1999), also affect intercellular communication, immune responses, neoplastic transformations and growth control, and cellular levels of enzymes that detoxify carcinogens (Zhang et al., 1991; Brockman et al., 1992; Pryor et al., 2000). To date studies carried out have used the rat (Foote et al., 1970; Gradelet et al., 1998) and the mule duckling model (Cheng et al., 2001) to show the protective effect of these carotenoids against AFB1 exposure. Of the well known carotenoids, lycopene and beta- carotene occur in abundance in fruits and vegetables and are safe for human consumption. Aflatoxin B1 frequently induces mutations of the p53 gene which is linked to HCC. Although there is much evidence from epidemiological studies linking the beneficial aspects of carotenoids to the prevention of cancer, the cellular and molecular mechanisms need to be understood in order to implement large scale intervention strategies to prevent AFB1 induced carcinoma. The use of chemical or dietary interventions to alter the susceptibility of humans to the actions of carcinogens and to block, retard or reverse carcinogenesis is an emerging chemoprotective strategy for disease prevention (Abdulla and Gruber, 2000; Kensler et al., 2003; Bingham and Riboli, 2004). Chemoprotection by natural products involves maintaining cellular integrity, preventing DNA alterations, activation of p53 suppressor protein and apoptosis. The aim of this study was thus to investigate the cellular and molecular mechanisms by which beta-carotene and lycopene may prevent the AFB1-induced toxic changes in human hepatocytes. In order to achieve this aim, the following objectives were set out: i. To optimise an in vitro system for the evaluation of AFB1 damage to cultured hepatocytes. ii. To determine the biochemical protection offered by beta-carotene and lycopene to AFB1-exposed hepatocytes, by measuring the mitochondrial activity, cell viability and ROS levels using appropriate enzyme assays and flow cytometry. iii. To determine the cellular protection offered by beta-carotene and lycopene to AFB1-exposed hepatocytes, by studying the morphological changes at the structural and ultrastructural levels using phase contrast light and electron microscopy respectively. iv. To determine the molecular protection offered by beta-carotene and lycopene to AFB1-exposed hepatocytes, by detecting apoptotic bodies as genomic markers and measuring the levels of p53 protein and AFB1-N7-guanine adducts produced.
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The effects of fumonisins on sphinganine and sphingosine levels in hepataocyte cultures, experimental animals and humansVan der Westhuizen, Liana 03 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT:
Please see fulltext for abstract / AFRIKAANSE OPSOMMING:
Sien asb volteks vir opsomming
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Mycotoxin levels in subsistence farming systems in South AfricaNcube, Edson 03 1900 (has links)
Thesis (MScAgric (Plant Pathology)--Stellenbosch University, 2008.
Includes bibliography.summary,list of figures and appendices. / ENGLISH ABSTRACT:
Fusarium spp. and Aspergillus spp. are toxin-producing fungi associated with maize and
groundnut. Fusarium verticillioides produces fumonisins in maize, and Aspergillus flavus
produces aflatoxins in maize and groundnut kernels. Both toxins are responsible for
carcinogenesis in humans and animals. Contamination of maize and groundnut with
mycotoxins is often most severe in rural areas where subsistence farmers are unaware of their
existence and follow agricultural practices that might contribute to their production. A
questionnaire was, therefore, compiled to investigate agricultural decisions in rural areas that
may influence mycotoxin contamination of crops. During 2006 and 2007, maize and
groundnut samples were collected in the Eastern Cape, KwaZulu-Natal (KZN), Limpopo, and
Mpumalanga provinces. Mycotoxin levels were quantified using the ELISA technique, and
the incidence of Fusarium spp. in maize grain was determined by plating maize kernels out on
Fusarium selective medium. Fumonisin-producing Fusarium spp. were also quantified using
real-time PCR (TaqMan). The incidence of A. flavus and A. parasiticus in groundnut was
determined by plating out kernels on potato dextrose agar. Fumonisin contamination levels in
maize samples ranged from 0-21.8 parts per million (ppm) and aflatoxin levels ranged from 0-
49 parts per billion (ppb), depending on the region where samples were collected. Aflatoxin
levels in groundnut ranged from 0-160.1 ppb. Fusarium verticillioides was the most common
Fusarium sp. in maize followed by F. subglutinans and F. proliferatum, respectively.
Regression analyses showed a positive correlation between fumonisin-producing Fusarium
species when determined by real-time PCR and fumonisin concentration (r2=0.866).
Regression analyses further showed a highly significant positive correlation between A. flavus
and aflatoxin contamination (r2=0.10235). Samples from northern KZN contained levels of
mycotoxins that were far in excess of the maximum levels set by the Food and Drug
Administration in the USA. In South Africa there are currently no regulations with regard to
the maximum allowable levels of fumonisin in human food. The high incidence of mycotoxin
contamination of human food in subsistence farming systems indicates the need for awareness
programmes and further research. / AFRIKAANSE OPSOMMING:
Fusarium spp. en Aspergillus spp. is toksien-produserende fungi wat met mielies en
grondbone geassosieer word. Fusarium verticillioides produseer fumonisiene in mielies,
terwyl, A. flavus aflatoksiene in mielies en grondbone produseer. Beide toksiene is
karsinogenies vir mens en dier. Die vlakke van toksien-kontaminasie is meestal die ergste in
landelike gebiede waar bestaansboere onbewus is daarvan. Landboupraktyke wat deur die
boere toegepas word vererger dikwels die probleem. ‘n Vraelys is saamgestel om vas te stel
watter landboupraktyke in landelike gebiede toegepas word, en hoe dit toksien-kontaminasie
in mielies en grondbone beinvloed. In die 2006 en 2007 seisoene is mielie- en
grondboonmonsters in Kwa-Zulu-Natal (KZN), die Oos Kaap, Limpopo en die Mpumalanga
provinsie versamel. Toksien-vlakke is gekwantifiseer deur gebruik te maak van die ELISA
tegniek. Die insidensie van Fusarium spp. in mielies was bepaal deur pitte op Fusariumselektiewe
agar uit te plaat. Fumonisien-produserende Fusarium spp. was ook gekwantifiseer
deur van kwantitatiewe PCR (TaqMan) gebruik te maak. Die voorkoms van A. flavus en A.
parasiticus is bepaal deurdat mielie- en grondboonpitte op aartappel dekstrose agar uit te
plaat. Fumonisien-vlakke in die mieliemonsters het gewissel van 0-21.8 dele per miljoen
(dpm), terwyl aflatoksienvlakke gewissel het van 0-49 dele per biljoen (dpb), afhangende van
die omgewing waar monsters versamel is. Aflatoksien vlakke in die grondboonmonsters het
gewissel van 0-160.1 dpb. Fusarium verticillioides is die meeste vanuit mielies geisoleer,
gevolg deur F. subglutinans en F. proliferatum. Regressie analises het ‘n positiewe korrelasie
tussen fumonisien konsentrasie en fumonisien-produserende spp. aangedui waar daar gebruik
gemaak is van die kwantitatiewe PCR (r2= 0.866). Regressie analises het ‘n hoogs
betekenisvolle positiewe korrelasie getoon tussen A. flavus en aflatoksien kontaminasie
(r2=0.10). Monsters van noordelike KZN het toksienvlakke bevat ver bokant die maksimum
toelaatbare vlakke is soos bepaal deur die Food en Drug Administrasie in die Verenigde State
van Amerika. Daar is tans geen regulasies in Suid Afrika wat die maksimum toelaatbare
vlakke van fumonisiene in voedsel vir menslike gebruik bepaal nie. Die hoë voorkoms van
mikotoksien-kontaminasie in bestaansboer-sisteme, dui die belangrikheid van verdere
navorsing en bewusmakings-progamme aan.
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Altered lipid metabolism as a possible mechanism in fumonisin-induced hepatocarcinogenesis in rats and investigations into risk assessment in humansBurger, Hester Maria 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Exposure to food contaminates such as mycotoxins have been associated with a
variety of animal and human diseases worldwide. In South Africa, maize is the most To further refine risk assessment in the socio-demographic heterogeneous
population of South Africa, the development and evaluation of a sensitive and
interactive model the Mycotoxin Risk Assessment Model (MYCORAM) proofed to be
more sensitive compared to the classical probable daily intake (PDI). The
development of the MYCORAM was based on mycotoxin distribution during dry
milling of maize in milling fractions intended for human consumption which was
superimposed on the maize intake profiles of the South African population. Although
dry milling, including a degerming step, is an effective way to reduce mycotoxins, risk
and exposure assessment are influenced by maize dietary intakes, gender and
ethnicity. This became evident when considering FB dietary exposure in rural maize
subsistence farming communities in the Eastern Cape Province, South Africa
confirmed the vulnerability of this subpopulation to risk of fumonisin exposure.
Specific maximum tolerated maximum levels (MTL) to safeguard these communities
fall outside the international regulatory processes and need to be urgently
addressed. With the complex nature of cancer development in mind, integration of
basic science and nutritional epidemiology will be important to contribute to our
understanding of the adverse effects of FB and to define relevant risk assessment
parameters.
important commercial grain crop not just economically but also as a local food
commodity both commercially and in subsistence rural farming communities. In order
to control and manage mycotoxin contamination in food, evidence-based risk
assessment is needed that includes mechanistic and human exposure studies. From
this perspective the current study was conducted and aimed in further unravelling
fumonisin B1 (FB1) mycotoxin induced hepatocarcinogenesis via the disruption of the
lipid metabolism. The study also critically evaluates aspects of human risk
assessment due to its relevance and importance to food safety known to impact on
food security. This entails mycotoxin distribution during maize dry milling and the
assessment of mycotoxin exposure in the South African population and vulnerable
rural communities at risk.
Fumonisin B1 affects the integrity of biological membranes by altering key lipid and
fatty acid parameter in plasma, microsomal, mitochondrial and nuclear subcellular
membrane fractions in rat liver. Changes in the major lipid constituents entailing an
increase in cholesterol (CHOL) and phosphatidylethanolamine (PE) whilst
sphingomyelin (SM) and phosphatidylcholine (PC) tended to decrease. Isolated
plasma membrane lipid rafts, from rat primary hepatocytes exposed to FB1
augments the intricate effects exerted on the lipid metabolism regarding CHOL, SM
and PE. The disruption of lipid and fatty acid constituents, such as arachidonic acid
and ceramide, are likely to be key determinants affecting growth regulatory signaling
pathways relevant to the critical balance between cell proliferation and apoptosis
during cancer promotion. These changes provide further evidence that FB1 induce
cancer promotion by differential inhibition and/or stimulation process whereby a few
resistant “initiated” hepatocytes proliferate in an environment where the growth of
normal cells is inhibited. A specific lipogenic phenotype is effected by FB1 which is
closely associated with cancer development and considered to occur via an
epigenetic-type of mechanism. These effects are not adequately addressed in
defining risk assessment parameters. / AFRIKAANSE OPSOMMING: Die blootstelling aan voedsel-kontaminante soos mikotoksienes word wêreldwyd met
‘n verskeidenheid van dierlike en menslike siektes geassosiseer. In Suid-Afrika word
mielies as ‘n belangrike graanoes beskou, nie net vir die ekonomie nie maar ook as
‘n plaaslike voedselproduk beide kommersieel en vir bestaansboere in landelike
gemeenskappe. Ten einde mikotoksien-kontaminasie van voedsel te kan beheer en
bestuur, vereis bewys-gebaseerde risiko-evaluering wat insluit meganistiese en
menslike blootstelling studies. Vanuit hierdie perspektief is die huidige studie
uitgevoer en gemik op die verdere ontleding van die fumonisin B1 (FB1) mikotoksien
geïnduseerde lewer-karsinogenese deur die ontwrigting van die lipiedmetabolisme.
Die studie ondersoek terselfdetyd aspekte van menslike risiko-evaluering ingevolge
die relevansie en belangrikheid hiervan in voedselveiligheid wat ook ‘n impak op
voedselsekerheid sal maak. Dit sluit in die verspreiding van mikotoksiene gedurende
die droëmaalproses van mielies en mikotoksien blootstelling in Suid-Afrika asook
onder kwesbare landelike gemeenskappe. Fumonisin B1 beïnvloed die integriteit van biologiese membrane deur die modulasie
van die belangrike lipied en vetsuur samestelling van plasma, mikrosomale,
mitochondriale en kern subsellulêre membraan-fraksies in rot lewer. Veranderinge in
die belangrike lipiedbestanddele, insluitende ‘n verhoging in cholesterol (CHOL) en
phosphatidylethanolamine (PE), terwyl sphingomyelin (SM) en phosphatidylcholine
(PC) geneig was om te verlaag. Geïsoleerde plasma membraan lipied vlotte (lipid
rafts), vanaf primêre rot hepatosiete blootgestel aan FB1, versterk die ingewikkelde
gevolge wat uitgeoefen word op die lipiedmetabolisme insluitende die voorgestelde
veranderings in CHOL, SM en PE vlakke. Die versteuring van lipiede en vetsure
soos aragidoonsuur (arachidonic acid) en ceramied kan beskou word as belangrike
determinante wat inmeng in groei-regulerende seinbane verwant aan die kritiese
balans tussen selgroei en seldood. Die versteurings verskaf verdere bewyse dat FB1
kanker bevorder deur ‘n seleksie proses wat onderskeidelike die onderdrukking en\of
die stimulasie van ‘n paar weerstandige of geneties veranderde hepatosiete laat
vermeerder in ‘n omgewing waar die groei van normale selle geïnhibeer word. Die
spesifieke lipogeniese fenotipe wat FB1 versoorsaak hou ten nouste verband met kankerontwikkeling en die voorkoms van epigenetiese-soort meganismes word
voorgestel. Hierdie oorsake word tans nie voldoende aangespreek tydens die
bepaling van risiko-evaluerings limiete nie.
Om risiko-bepaling verder te verbeter in die sosio-demografies heterogene populasie
van Suid-Afrika, was die ontwikkeling en evalueering van ‘n sensitiewe en
interaktiewe model, die “Mycotoxin Risk Assessment Model” (MYCORAM) meer
doeltreffend vergeleke met die gewone waarskynlike daaglikse inname. Die
ontwikkeling van die MYCORAM was gebaseer op die mikotoksien verspreiding
tydens die droëmaalproses van mielies in fraksies wat vir menslike verbruik bedoel
was tesame met mielie dieetinnames van die Suid-Afrikaanse populasie. Alhoewel,
die droëmaalproses van mielies, insluitende die verwydering van die kiem
doeltreffende maniere is om mikotoksienes te verminder, word risiko- en
blootstellings evaluering beinvloed deur mielie dieetinnames, geslag en etnieseverbandskap.
Hierdie was veral opmerklik gedurende blootstelling aan FB in die
dieet van landelike mielie bestaansboer gemeenskappe in die Oos-Kaap van Suid-
Afrika en bevestig hoe kwesbaar hierdie populasie is. Spesifieke maksimum
toelaatbare vlakke om hierdie gemeenskappe te beskerm val buite die huidige
internasionale regulatoriese prosesse en benodig dringende aandag. Met die
ingewikkelde aard van kankerontwikkeling in gedagte, sal die integrasie van basiese
wetenskappe en voedingsepidemiologie, ‘n belangrik bydrae lewer tot die kennis van
die negatiewe eienskappe van FB om toepaslike risiko-evaluerings limiete te kan
bepaal.
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Mycotoxicological properties of fusarium verticillioides and the fumonisins : mechanisms and implications for setting risk assessment parameters in humansGelderblom, Wentzel Christoffel Andreas 03 1900 (has links)
Thesis (DSc (Biochemistry))--Stellenbosch University, 2009. / The fumonisin mycotoxins are known to be the causative principle for several animal
diseases and are associated with the development of liver and oesophagus cancer
and neural tube defects in humans. The thesis focuses mainly on the
characterisation of the compounds from maize cultures of the fungus Fusarium
verticillioides, isolated from maize, the toxicological effects in animals, mechanism
involved in hepato- and nephrocarcinogenicity and discussing the major differences
and contradictions in the literature together with their impact on setting relevant risk
assessment parameters to safeguard human health. Controversies include the
importance of non-genotoxicity vs genotoxicity in the development of cancer, the role
of threshold effects in carcinogenesis and the establishment of realistic risk
assessment parameters that will also be applicable in developing countries. Recent
approaches suggest that thresholds should also apply for genotoxic carcinogens as
interaction with the DNA is only one event in the multi-step process of cancer
development and therefore could not be taken as the basis for applying a no-effect
threshold for genotoxins. It would appear that a carcinogen such as fumonisin,
whether it is labeled genotoxic or non-genotoxic per se, exhibits some degree of risk
at any level due to additive or synergistic interactions with other xenobiotics and/or
dietary constituents. The underlying mechanisms of fumonisin-induced
carcinogenicity includes the disruption of sphingolipid, phospholipids and fatty acid
metabolism, which plays a major role in the modulation of apoptotic and cell
proliferative pathways related to cancer development. Interactive responses between
arachidonic acid and ceramide affect downstream cell signal transduction pathways
and depending on the cell type the disruption of these pathways could either
stimulate or inhibit cell proliferation which eventually will determine the induction of
apoptosis and hence affect cell survival. The modulating roles of dietary constituents
such as vitamins, protein and the South African herbal teas are also highlighted as
they affected the outcome of toxicological assays, thus determining thresholds of the
adverse effects in specific target organs that will impact risk assessment parameters.
Regulation of the fumonisins in food and the associated risk are debated from many
perspectives. In developing countries there is a lack of quality control implying that
maize highly contaminated with mycotoxins may directly enter the food chain of
adults and children as control of mycotoxins is difficult or in some cases totally
absent. The interaction of politics, economy and technology will eventually determine
the impact on health as the regulation of fumonisin in food differs between countries.
Knowledge about the biological effects of the fumonisins is currently playing an
important role in the development of simple and inexpensive methods to reduce the
levels of the fumonisin in maize by targeting specific populations at risk.
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Rôle des enzymes du métabolisme des xénobiotiques dans la toxicité pulmonaire de deux mycotoxines d’Aspergillus versicolor et d’Aspergillus nidulans / Role of xenobiotics metabolism enzymes in the pulmonary toxicity of two Aspergillus versicolor and Aspergillus nidulans mycotoxinsCabaret, Odile 04 November 2011 (has links)
Les connaissances sur les risques liés à l'inhalation de mycotoxines restent limitées, alors que ces toxines, présentes au niveau des spores fongiques, peuvent atteindre directement les épithéliums respiratoires. Les enzymes du métabolisme des xéniobiotiques pulmonaires peuvent moduler la toxicité de ces mycotoxines en les détoxifiant ou en formant des métabolites plus réactifs. Notre objectif était d'étudier in vitro le métabolisme pulmonaire de la stérigmatocystine et de la méthoxy-stérigmatocystine, deux mycotoxines présentes dans les environnements contaminés par les moisissures, et de prédire les éventuelles conséquences toxiques. L'étude du métabolisme en présence de cytochromes P450 exprimés dans des systèmes hétérologues, puis dans un modèle de culture primaire de cellules épithéliales trachéales porcines, a montré que ces mycotoxines étaient oxydées, principalement par les cytochromes P450 1A, et conjuguées par glucucoridation et sulfo-conjugaison. Ces deux toxines semblent principalement détoxifiées au niveau pulmonaire. Si une activation métabolique de la stérigmatocystine est possible, celle-ci semble limitée / Human health effects of inhaled mycotoxins remains poorly documented, despite these toxins are present in fungal spores et can directly reach the airway epithelia. Xenobiotic metabolozing enzymes can modulate lung toxicity of these mycotoxins through detoxification or reactive metabolite formation. Our aim was to study in vitro the metabolism and the cellular toxic consequences of two mycotoxins present in mold-contaminated environments, e.g. sterigmatocystin and methoxy-sterigmatocystin. The metabolism studies using recombinant cytochromes P450 enzymes and porcine tracheal epithelial cell primary cultures, showed that these mycotoxins could be oxidized by cytochrome P450 1A and conjugated by glucucoridation and sulfo-conjugation. Sterigmatocystin and methoxysterigmatocystin seem mainly detoxified in respiratory cells. If a metabolic activation of sterigmatocystin is possible, it seems limited
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Využití plazmových technologií ke zlepšení kvality krmiv / The Usage of Plasma Technologies to Improve the Quality of FeedstuffsHAVELKA, Zbyněk January 2019 (has links)
The dissertation thesis deals with the problems of the use of plasma technologies in agriculture for the purpose of improving the quality of feedstuffs for agricultural animals. The attention is focused above all on the use of low-temperature gliding arc plasma discharge generated by the atmospheric pressure for the elimination of model fungal pathogens (T. virens) and for the testing of the possibility of the use of plasma for the decreasing of mycotoxin load (DON and D3G). The professional orientation of the dissertation thesis is strongly interdisciplinary with the overlap to the area of the physics of plasma, microbiology, zootechnics and the proposal and construction of technical facilities. With that corresponds also the division of thesis into individual chapters. In the research part, there is a summary of actual pieces of knowledge from the area of fungal microorganisms and mycotoxins produced by these with the view on their presence in feedstuffs. There follows a research of pieces of knowledge of low-temperature plasma and its applications in the food industry and feeding. In the chapter Material and Methodology, the applicated methods of work, employed instruments and biological material are described. The resulting part is, for its clear arrangement, divided into five subchapters ? stating of selected parameters of plasma device, influence of plasma on nutritional parameters, influence of plasma on the model fungus Trichoderma virens and possibilities of the use of plasma discharge for the decreasing of concentration of mycotoxins in feedstuffs. The final part is dedicated to the description of system which enables the treatment of samples in continuous regime. The treatment of mycelial discs by plasma discharge lead to the decrease of germination capacity of spores of fungi, while there was experimentally proven the synergic effect of the influence of individual mechanisms by which the plasma interacts with the surface of biological material. At the same time, there was not observed a more significant change in the composition of feedstuffs, more significant is only the change of humidity of sample. In the laboratory conditions, the decreasing of concentration of mycotoxins spread on laboratory glass was proven. At the samples of feedstuffs contaminated by natural way, it was not successful to reliably provedecreasing of concentration of mycotoxins in a sample as a result of plasma activity.
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A comparison of the farnesyl pyrophosphate and B-cyclopiazonic acid synthases from penicillium cyclopiumHarrison, Duncan 26 January 2015 (has links)
No description available.
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Ocorrência de aflatoxinas e fumonisinas em sistema de produção de frangos de corte no Estado de São Paulo. / Occurrence of aflatoxin and fumonisin in a poultry productive system in the state of São Paulo.Kobashigawa, Estela 21 December 2010 (has links)
O objetivo deste estudo foi verificar a ocorrência de aflatoxina e fumonisina no sistema de produção de frango de corte e o impacto destas micotoxinas nos índices produtivos em uma empresa integradora localizada no Estado de São Paulo. Adicionalmente, foram identificados os principais fatores para a produção de micotoxinas em rações e a ocorrência de resíduos de aflatoxinas e fumonisinas em tecidos comestíveis de frango (músculo peitoral, fígado e moela). Foram realizadas as contagens de fungos e leveduras totais, de fungos dos gêneros Aspergillus ssp. e Fusarium ssp. e quantificação de aflatoxina e fumonisina nas principais matérias-primas da ração (milho e farelo de soja), na ração de abate e na cama de frango. O isolamento de fungos nas amostras de milho, farelo de soja e ração foi realizado em ágar DG18, enquanto que, para as amostras de cama de frango, utilizou-se o ágar PDA. Para a extração de aflatoxinas e fumonisinas, foram utilizadas colunas de imunoafinidade (Neogen®) e colunas SAX de troca iônica, respectivamente. A quantificação das aflatoxinas e fumonisinas foi realizada através de cromatografia líquida de alta eficiência (CLAE). O milho foi o alimento onde foi observada a maior frequência de Aspergillus ssp. e Fusarium ssp., e também maior positividade para aflatoxinas e fumonisinas, sendo que uma das amostras ultrapassou o limite de aflatoxinas recomendado pelo Ministério da Agricultura Pecuária e Abastecimento (MAPA). As quantidades de aflatoxinas e fumonisinas encontradas na ração não influenciaram significativamente os índices produtivos. Não foram encontrados níveis detectáveis de resíduos de aflatoxinas e fumonisinas nos tecidos analisados. Embora não tenham sido observadas lesões macroscópicas no fígado e bursa das aves, foram constatadas alterações histopatológicas nessas vísceras, as quais são compatíveis com lesões causadas pela ingestão de aflatoxinas e fumonisinas. / The objective of this study was to verify the occurrence of aflatoxin and fumonisin in poultry feed and their influence on poultry productivity at company located in São Paulo State. Supplementary, were identified the main factors that cause mycotoxin production in poultry feed and determine the occurrence of aflatoxins and fumonisins residues in edible parts of poultry (breast, liver and gizzard). The total mold and yeast counting of Aspergillus ssp. and Fusarium ssp. genus and quantification of aflatoxin and fumonisin were determined in the main feed ingredients (corn and soybean meal), in finishing diets and bedding. The fungi from corn, soybean meal and feed were isolated in DG18 agar, whereas, the fungi from bedding was used PDA agar. Aflatoxins and fumonisins, were extracted using an immunoaffinity column (Neogen®) and a SAX column, respectively. Aflatoxins and fumonisins were quantified by high performance liquid chromatografy (HPLC). The corn showed the highest frequency of Aspergillus ssp. and Fusarium ssp. and also the highest positivity for aflatoxins and fumonisins, there was one corn sample that exceeded the recommendations of the Brazilian Ministry of Agriculture. The levels of aflatoxins and fumonisins in the feed did not significantly influence productivity. There were not detectable levels of aflatoxins and fumonisins on analysed tissues. Although macroscopic lesions were not observed in liver and bursa, histopathological changes were observed in these organs, which are consistent with injuries caused by the aflatoxin and fumonisin consumption.
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