Growth-independent inhibition of aflatoxin biosynthesis with selected nanoparticles
Inventors
Assignees
Publication Number
US-12108764-B2
Publication Date
2024-10-08
Expiration Date
2038-03-05
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
Methods for inhibiting fungal secondary metabolisms are described. Secondary metabolisms inhibited by the methods can include those responsible for expression of mycotoxins such as aflatoxin. Methods can include inhibition of aflatoxin production without inhibiting fungal growth by contacting a fungus with a suspension including silver nanoparticles that can include a surface coating. The methods can be utilized in preventing fungal-caused destruction of plant species (e.g., crop species). Disclosed methods encompass utilization of silver nanoparticles at low concentrations of from about 10 picograms per liter to about 1 microgram per liter.
Core Innovation
The invention describes methods for inhibiting fungal secondary metabolism, specifically targeting the production of mycotoxins such as aflatoxin, without inhibiting fungal growth. The approach involves contacting a fungus with a suspension containing silver nanoparticles, which may possess a surface coating and are provided at low concentrations, specifically from about 10 picograms per liter to about 1 microgram per liter. These methods are particularly suited for use against fungal plant pathogens, including mycotoxin-producing filamentous fungi.
A significant problem addressed by this invention is that past studies on silver nanoparticles have focused primarily on growth-dependent repression of secondary metabolism in fungi, often leading to growth inhibition. There is a need for methods that utilize nanoparticles at doses that repress undesirable secondary metabolism, such as production of aflatoxin, while not inhibiting the growth of the fungi themselves. Such approaches can prevent fungal-caused destruction of important plant species, like crop species, without negative consequences to plant health or environmental disruption caused by complete elimination of the fungal presence.
The disclosed invention demonstrates that silver nanoparticles, especially with a surface coating such as citrate or polyvinyl pyrrolidone and sized between about 15 to 30 nanometers, can inhibit aflatoxin production in fungi such as Aspergillus parasiticus at concentrations that do not significantly affect fungal growth rates. The inhibition of aflatoxin biosynthesis occurs at the level of transcriptional activation of biosynthetic gene clusters and global regulators (e.g., laeA and veA), with an associated reduction in intracellular reactive oxygen species. Importantly, upon depletion of the nanoparticles from the growth medium, the fungi regain normal aflatoxin production capabilities, confirming the specificity and temporary nature of the inhibition.
Claims Coverage
The patent contains a single independent claim, which establishes the inventive features of the method for inhibiting aflatoxin production in fungi using specifically processed silver nanoparticles.
Method for inhibiting aflatoxin production using specific silver nanoparticles
The invention provides a method comprising: 1. Forming a first suspension of silver nanoparticles that have a surface coating and an average size of 15 to 30 nanometers as determined by transmission electron microscopy. 2. Separating these coated silver nanoparticles by ultrafiltration in a diafiltration mode. 3. Redispersing the coated silver nanoparticles in a second suspension so that the coated nanoparticles are present at a concentration of 25 to 60 nanograms per milliliter. 4. Contacting the fungus with the second suspension, resulting in inhibition of aflatoxin production during the period of contact, without significantly decreasing the fungal growth rate as measured by dry weight accumulation per unit time. These features allow for the selective inhibition of secondary metabolite production, specifically aflatoxins, in fungi such as mycotoxin-producing filamentous fungi and Aspergillus parasiticus, using nanoparticles of defined size, coating, purification, and concentration.
The inventive feature centers on a defined process for inhibiting aflatoxin production in fungi through the use of surface-coated silver nanoparticles of specific size and in precise concentration ranges, resulting in temporary, growth-independent suppression of mycotoxin biosynthesis.
Stated Advantages
Provides inhibition of fungal secondary metabolism, such as aflatoxin production, without inhibiting fungal growth.
Enables prevention of fungal-caused destruction of plant species (e.g., crop species) without negative impacts on plant health or the local environment caused by complete destruction of fungal growth.
Functions at lower concentrations of silver nanoparticles than those typically used in toxicological and ecotoxicological studies, minimizing risk to human health and the environment.
Allows for temporary and non-lethal inhibition of aflatoxin production, with fungi regaining normal function after nanoparticle depletion.
Demonstrates feasibility for application to various mycotoxin-producing filamentous fungi.
Documented Applications
Preventing fungal-caused destruction of plant species, such as crop species, by inhibiting mycotoxin production.
Use with fungal plant pathogens, specifically mycotoxin-producing filamentous fungi including Aspergillus parasiticus.
Interested in licensing this patent?