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United States Department of Agriculture (USDA) 2019


Bioactive Natural Products Medecine Arid

United States Department of Agriculture (USDA) National Institute of Food and Agriculture


Identification : 1020652

Pays : Etats Unis

Durée : START : 01 OCT 2019 TERM : 30 SEP 2024

Discovery of novel bioactive natural products is necessary for the identification of new pharmaceuticals and agricultural agents (herbicides and pesticides). We will use plants and microorganisms from arid and semiarid environments to identify such natural products ; characterize the enzymes that produce them ; and isolate the genes that encode their biosynthesis. We will use the purified natural products in various biological tests to elucidate their biological activities, and we will determine the chemical structures of the compounds that show interesting activities. We will use the enzymes and their encoding genes to change the chemical structures of these natural products, or to produce completely new "unnatural natural products" using cellular factories in "domesticated" microorganisms. Discovering such novel bioactive chemical compounds, and developing them to practical, useful agents will improve human health, agricultural productivity and safety, and the economic prospects of our State and Nation.Guaranteeing the safety of our produce is important for public health. For example, leafy green vegetables and melons are usually consumed raw, thus pre- or post-harvest decontamination is very important to prevent foodborne illnesses. Interventions currently used by the fresh produce industry include chemical sanitizers, the most common being chlorine. However, studies show that chlorine is not very effective in reducing bacterial populations on fresh produce. Plant-based antimicrobials are well known for their antimicrobial activity and are natural healthy products. Many bacteria produce antibacterial compounds called bacteriocins, which possess killing activities with much higher specificity than commonly used antibiotics. We propose to use plant-based antimicrobials such as plant extracts, essential oils and their active components to treat leafy greens and melons post-harvest and bacteriocins (tailocins) pre-harvest in order to reduce the population of foodborne pathogens such as E. coli O157:H7, Salmonella and L. monocytogenes on these produce. We expect the pathogen population will be largely reduced after the treatments. The results could provide the produce industry with natural alternatives to chemical based sanitizers such as chlorine.

This proposed project involves the following research objectives:Screen arid-land plants and microorganisms for the presence of bioactive compounds ;Conduct bioassay-directed fractionation of extracts with demonstrated biological activity and elucidate the structures of bioactive NPs ;Characterize and manipulate the biosynthesis of selected bioactive NPs ;Further develop alternative agricultural systems, especially aeroponics system for plant cultivation, and for the production and structural diversification of plant-derived NPs of economic importance ;Produce analogues of major NPs by chemical transformations and microbial biotransformations ;Produce novel unnatural natural products (uNPs) by combinatorial synthetic microbiology ;Evaluate promising lead NPs and their analogues with collaborators in other University of Arizona departments and colleges, other academic institutions, government agencies, and private industry ;Evaluate plant-based antimicrobials including plant extracts, essential oils and their active components against E. coli O157:H7, S. enterica, and L. monocytogenes in vitro and on produce ;Test whether application of tailocins to spinach and lettuce prevents colonization by E. coli O157:H7 ;Characterize Pseudomonas strains for the ability to produce tailocins that are effective against E. coli O157:H7, S. enterica and L. monocytogenes.

Performing Institution : UNIVERSITY OF ARIZONA
Investigator : Molnar, I, . ; Gunatilaka, LE, A.. ; Ravishankar, SA, .

Présentation : USDA (NIFA)

Page publiée le 28 novembre 2021