1a. Objectives (from AD-416):
Assays for detecting low molecular weight toxins rely upon components that can interact with the toxins and facilitate toxin isolation or detection. Because of this, the goal of developing assays with better performance characteristics (such as sensitivity, speed, and robustness) requires the development of improved materials that bind the toxins. To meet this goal, we propose four objectives: Objective 1: Develop novel biologically-based materials that bind foodborne toxicants; Objective 2: Design and develop synthetic-based materials for detection of agricultural and food-related toxins; Objective 3: Develop computational methods for foodborne toxins that enable new strategies to reduce exposure; Objective 4: Develop detection strategies for emerging toxins and toxins of commercial importance.
1b. Approach (from AD-416):
Toxins produced by fungi, mycotoxins, can cause devastating economic effects by affecting the safety and marketability of grain, and by causing disease in livestock. Diagnosis of health problems caused by mycotoxins is often difficult because while certain of the toxins can cause acute disease, most cause sub-acute or chronic effects that are more difficult to discern. For these reasons, attempts are made to detect mycotoxins at the many stages from crop production to finished product. As a result, a vital part of mycotoxin control is the availability of rapid, accurate, sensitive, and cost effective methods for toxin detection and quantitation. Fortunately, many such methods exist and are commercially available. With a few exceptions, most of these methods rely, in some fashion, on components that bind the toxins. Ideally, the binding components are highly specific for the toxins of interest and are capable of performing under their expected conditions of use. As analytical technologies progress, assays are required to perform under increasingly demanding conditions, requiring advances in their component materials. We propose to apply the expertise of the investigators in synthetic chemistry, antibody development, immunoassay and sensor development, and instrumental assay methodology, toward the development of the next generation of toxin binding materials, such materials being the fundamental basis of improved analytical technologies for these toxins. By improving technologies for detecting natural toxins, this project will have a direct impact on the ability of producers, processors, and regulatory agencies to improve monitoring programs for natural toxins, and thereby improve the safety of the U.S. food supply.
3. Progress Report:
The interactions between fungi and plants can yield metabolites that are toxic to animals. Certain fungi that commonly infest grains are known to produce a potent toxin known as T-2 toxin. T-2 is acutely toxic and has been found at low levels in crops such as wheat, corn, barley, oats, and rye and in human food and animal feeds. Plants, animals, and fungi protect themselves from toxins through a variety of mechanisms, including glucosylation, which attaches a sugar to the toxin. In general such products are less hazardous than the parent toxins. Unfortunately they can also serve as a ‘reservoir’, from which the toxin may be regenerated. The glucosylated forms of T-2 toxin have been found in grain and are of interest as potential reservoirs of T-2 toxin that are not detected by many analytical methods. In this research, scientists at the Bacterial Foodborne Pathogens & Mycology Research Unit of the National Center for Agricultural Utilization Research, Peoria, Illinois, generated antibodies directed against the glucoside of T-2 toxin. From 10 such antibodies, one was selected that was able to be used in sensitive assays to detect both T-2 toxin and its glucoside. The antibody provides researchers with a new tool that will be used to develop better ways to detect this heretofore ‘masked’ mycotoxin. Many countries have problems with naturally occurring toxins in grains. One such toxin is deoxynivalenol (DON), which is commonly found in wheat, barley, and corn. When grains are processed, DON does not distribute equally among the fractions. The increasing inclusion of bran into food formulations, as a source of dietary fiber, necessitates increased monitoring for DON in such fractions. As part of efforts to improve monitoring of the toxin, a method for detecting DON in wheat bran and whole-wheat flour using fluorescence polarization immunoassay was developed at the Institute of Sciences of Food Production (ISPA) in Bari, Italy, with help from ARS, Peoria, Illinois. The technique was successfully used to measure DON in samples of naturally contaminated bran and whole-wheat flours, with results that agreed well with a reference method. The result is a rapid method that can be used to monitor DON in wheat bran and whole-wheat flour. Fusaric acid is a mycotoxin and phytotoxin produced by a variety of Fusarium species and can be found in maize. Existing methods to detect fusaric acid are either crude or require very expensive equipment. To aid in the isolation and detection of fusaric acid, ARS scientists in collaboration with researchers at Central Michigan University, synthesized polymers imprinted with picolinic acid. A solid phase extraction method was developed and evaluated as a means to isolate fusaric acid from maize.
Shephard, G.S., Berthiller, F., Burdaspal, P.A., Crews, C., Jonker, M.A., Krska, R., Lattanzio, V., MacDonald, S., Malone, R.J., Maragos, C.M., et al. 2013. Developments in mycotoxin analysis: An update for 2011-2012. World Mycotoxin Journal. 6(1):3-30.