Growth and mycotoxin production by Chaetomium globosum
Fogle, Matthew R.
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Sick 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.