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United States Department of Agriculture

Agricultural Research Service

Research Project: Chemical Approaches to Eliminate Fungal Contamination and Mycotoxin Production in Plant Products

Location: Foodborne Toxin Detection and Prevention Research

2011 Annual Report

4. Accomplishments
1. Improving the efficacy of commercial fungicides with natural products. Human fungal diseases are very difficult to treat and the fungi causing these diseases are often resistant to the antifungal drugs currently available. ARS scientists at Albany, California, are looking for new methods to improve antifungal drugs. A number of safe, natural phenolic compounds were identified that synergize the activity of antifungal drugs against yeast pathogens, such as Candida sp. and Cryptococcus neoformans, two yeast pathogens that are commonly associated with mortality of humans suffering from immunodeficiency diseases. These compounds will be tested on drug resistant strains of these yeast pathogens being identified by Portuguese collaborators. This may have significant impact on the chemotherapy of patients suffering from these diseases.

2. Discovery of new target to control fungal pathogens. Fungi that infect crops are a major problem in agriculture. ARS scientists at Albany, California, are looking for new targets in fungi to improve the ability to kill them with antifungal agents. A new target for control of agricultural fungal pathogens has been identified. This target involves use of compounds that disrupt the mitochondrial respiratory complex. By disrupting this complex, we found the ability to create a vast synergism using antifungal agents. This finding could greatly impact use of agricultural fungicides, reducing dosages and costs, and concomitantly reduce the environmental hazards associated with their use.

3. Degradation of aflatoxin by microbes. Aflatoxin is a potent carcinogen that can contaminate food. ARS scientists at Albany, California, and Russian collaborators are trying to find ways to decontaminate aflatoxin contaminated products. Several culturable fungi have been identified that can completely degrade aflatoxin, when added to the culture media. The potential exists for identifying the aflatoxin degrading enzymes. Development of aflatoxin degrading technology could have some industrial application which would have a major impact on food safety and economic value of food commodities germane to the problem of aflatoxin contamination.

4. Finding the best volatile blend for the navel orangeworm (NOW). NOW feeding damage allows fungal infection of almonds. Control of this insect might be possible by using traps that have chemicals that serve as a lure. Some of these chemicals exist in almond orchards; they only need to be identified. Several candidate blends, based on volatile analyses are currently undergoing intensive field trapping studies for female NOW attractancy efficacy by ARS scientists in Albany, CA. There are combinations of such compounds that show great promise as an effective lure of NOW. These lures will be a significant tool for controlling NOW, the major insect pest of almonds and pistachios.

Review Publications
Beck, J.J., Higbee, B.S., Gee, W.S., Dragull, K.D. 2011. Ambient orchard volatiles from California almonds. Phytochemistry Letters. 4(2):199-202.

Beck, J.J., Mahoney, N.E., Cook, D., Gee, W.S. 2011. Volatile analysis of ground almonds contaminated with naturally occurring fungi. Journal of Agricultural and Food Chemistry. 59(11):6180-6187.

Faria, N.C., Kim, J.H., Goncalves, L., Martins, M., Chan, K.L., Campbell, B.C. 2011. Enhanced activity of antifungal drugs using natural phenolics against yeast strains of Candida and Cryptococcus. Letters in Applied Microbiology. 52:506-513.

Chang, P.-K., Scharfenstein, L.L., Luo, M., Mahoney, N.E., Molyneux, R.J., Yu, J., Brown, R.L., Campbell, B.C. 2011. Loss of msnA, a putative stress regulatory gene, in Aspergillus parasiticus and Aspergillus flavus increased production of conidia, aflatoxins and kojic acid. Toxins. 3:82-104.

Knight, A.L., Light, D.M., Trimble, R.M. 2011. Identifying (E)-4,8-dimethyl-1,3,7-nonatriene plus acetic acid as a new lure for male and female codling moth (Lepidoptera: Tortricidae). Environmental Entomology. 40(2):420-430.

Kim, J.H., Chan, K.L., Mahoney, N.E., Campbell, B.C. 2011. Antifungal activity of redox-active benzaldehydes that target cellular antioxidation. Annals of Clinical Microbiology and Antimicrobials. 10:23.DOI:10.1186/1476-0711-10-23.

Last Modified: 2/23/2016
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