Browsing by Subject "Mycotoxin"
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Item Growth and mycotoxin production by Chaetomium globosum(Texas Tech University, 2007-05) Fogle, Matthew R.; Straus, David C.; Hamood, Abdul N.; Fralick, Joe A.; Dickerson, Richard L.; Bright, RobertSick building syndrome (SBS) is a term commonly used to describe a set of non-specific symptoms resulting from poor indoor air quality (IAQ). These symptoms include: irritation of the eyes, nose and throat, dry skin, fatigue, headache, nausea, dizziness, increased number of respiratory tract infections, hoarseness, and wheezing. Over the last several years, mounting evidence has shown that fungal contamination within buildings is associated with SBS. The focus of this project is on a filamentous fungus called Chaetomium globosum which produces chaetoglobosins A (Ch-A) and C (Ch-C) when cultured on building material. Both metabolites belong to a group of toxins called the cytochalasins which exert their effects on mammalian cells by binding to actin. The production of Ch-A and Ch-C may contribute to the adverse health effects described by building occupants exposed to C. globosum. Therefore, examination of the growth of C. globosum and its mycotoxin production is important with regard to determining if there is a link between adverse health effects and exposure to Ch-A and Ch-C. This study had four major objectives: (1) to determine the frequency at which Chaetomium species are isolated in water-damaged buildings, (2) to examine the production of Ch-A and Ch-C in isolates of C. globosum obtained from different buildings, (3) to examine heat stability and water solubility of Ch-A and Ch-C, and (4) to examine the effects of ambient pH on growth and mycotoxin production by C. globosum. We found that Chaetomium species were commonly isolated from water-damaged buildings. Out of 30 C. globosum isolates, 16 produced detectable amounts of Ch-A and every isolate produced Ch-C. C. globosum grows best and produces the highest amount of Ch-C at a neutral pH. Ch-A and Ch-A were relatively stable when exposed to 50oC up to 3 days; however, decreased amounts were detected at longer exposure times. Exposure to 75oC and higher temperatures resulted in rapid breakdown of Ch-A and Ch-C. Both compounds were poorly soluble in water.Item The mechanisms of neurotoxicity induced by a Stachybotrys chartarum Trichothecene Mycotoxin in an in vitro model(2005-05) Karunasena, Enusha; Straus, David C.; Bright, Robert K.; McVay, Catherine S.; Hamood, Abdul N.; Strahlendorf, Jean C.Sick-building syndrome (SBS) is a phenomenon in which individuals in buildings with poor indoor air quality (IAQ) experience health problems associated with the environment of the building. Fungal contamination in buildings due to species such as Stachybotrys chartarum and Penicillium chrysogenum has been correlated to poor IAQ. Symptoms experienced by individuals exposed to mycotoxins produced by Stachybotrys species include, headaches, fatigue, nausea, vomiting, bleeding from mucosal membranes, depression, sleep disturbances, anxiety, vertigo, memory-loss and seizures. Although these symptoms have been observed in individuals exposed to Stachybotrys sp. mycotoxins, the mechanisms by which these compounds may contribute to neurotoxicity are unknown. In this study, a series of experiments were conducted on human brain-capillary endothelial cells (HBCEC), astrocytes, and progenitor neuronal cells. The purpose of this study was to evaluate the effects induced by satratoxin H on neural tissues; this includes the HBCEC which forms the blood-brain barrier, followed by the astrocytes which act as immune cells, and the neurons. These cell lines were exposed to satratoxin H at concentrations ranging from 1ng/ml to 5000ng/ml. These data were compared to controls; cells exposed to known inflammatory compounds such as lipopolysaccharide (LPS), cells exposed to oxidative stress induced by hydrogen peroxide (H202), and to both LPS and H202 with satratoxin H. Immunofluorescent examination was used to evaluate apoptosis events, and the expression of cellular receptors including. Supernatants and cellular extracts were examined for inflammatory agents as well as compounds associated with apoptosis. The results of these studies demonstrated that at satratoxin H concentrations (1ng/ml- 10ng/ml), results were similar to control cells, while cells exposed to moderate concentrations of 100ng/ml-1000ng/ml of satratoxin H alone or with LPS or H202, demonstrated high expression of inflammatory and apoptotic events. These experiments demonstrate that the macrocyclic trichothecenes produced by Stachybotrys chartarum are able to induce apoptotic and inflammatory cascades in endothelial cells, astrocytes, and neurons. These studies suggest that exposure to low to moderate doses of satratoxin could activate cellular pathways that induce a series of events leading to neurological tissue damage, which may induce the symptoms observed in individuals exposed to Stachybotrys chartarum.Item The mechanisms of neurotoxicity induced by a stachybotrys chartarum trichothecene mycotoxin in an in vitro model(Texas Tech University, 2005-05) Karunasena, Enusha; Straus, David C.; Bright, Robert K.; McVay, Catherine S.; Hamood, Abdul N.; Strahlendorf, Jean C.Sick-building syndrome (SBS) is a phenomenon in which individuals in buildings with poor indoor air quality (IAQ) experience health problems associated with the environment of the building. Fungal contamination in buildings due to species such as Stachybotrys chartarum and Penicillium chrysogenum has been correlated to poor IAQ. Symptoms experienced by individuals exposed to mycotoxins produced by Stachybotrys species include, headaches, fatigue, nausea, vomiting, bleeding from mucosal membranes, depression, sleep disturbances, anxiety, vertigo, memory-loss and seizures. Although these symptoms have been observed in individuals exposed to Stachybotrys sp. mycotoxins, the mechanisms by which these compounds may contribute to neurotoxicity are unknown. In this study, a series of experiments were conducted on human brain-capillary endothelial cells (HBCEC), astrocytes, and progenitor neuronal cells. The purpose of this study was to evaluate the effects induced by satratoxin H on neural tissues; this includes the HBCEC which forms the blood-brain barrier, followed by the astrocytes which act as immune cells, and the neurons. These cell lines were exposed to satratoxin H at concentrations ranging from 1ng/ml to 5000ng/ml. These data were compared to controls; cells exposed to known inflammatory compounds such as lipopolysaccharide (LPS), cells exposed to oxidative stress induced by hydrogen peroxide (H202), and to both LPS and H202 with satratoxin H. Immunofluorescent examination was used to evaluate apoptosis events, and the expression of cellular receptors including. Supernatants and cellular extracts were examined for inflammatory agents as well as compounds associated with apoptosis. The results of these studies demonstrated that at satratoxin H concentrations (1ng/ml- 10ng/ml), results were similar to control cells, while cells exposed to moderate concentrations of 100ng/ml-1000ng/ml of satratoxin H alone or with LPS or H202, demonstrated high expression of inflammatory and apoptotic events. These experiments demonstrate that the macrocyclic trichothecenes produced by Stachybotrys chartarum are able to induce apoptotic and inflammatory cascades in endothelial cells, astrocytes, and neurons. These studies suggest that exposure to low to moderate doses of satratoxin could activate cellular pathways that induce a series of events leading to neurological tissue damage, which may induce the symptoms observed in individuals exposed to Stachybotrys chartarum.