Phytochemical power against AHPND: new hope for the shrimp breeding

Phytochemical power against AHPND: new hope for the shrimp breeding

Garnel production in Southeast Asia is currently being threatened by a new illness: the acute Hepato-Pancreatic necrosis (AHPND). This bacterial disease particularly affects the Pacific white shrimp, Litopenaeus Vannamei, an economically very important way. A dangerous pathogen, Vibrio Parahaemolyticus, was identified as a central sick maker. This pathogen can carry a gene that encodes toxic proteins that destroy the cells by triggering their death.

The current research has examined paths to make these toxic proteins harmless. Four plant substances were discovered as promising: Myrictine, (+)-Taxifolin, (-)-Epigallocatechin-3-Gallate (EGCG) and Strychnin. In particular (+)-taxifolin and EGCG showed good effectiveness in laboratory tests by impairing the stability of the protein structures of the pathogen and thus contaminating their destructive effects.

The researchers also tested the antibacterial effectiveness of these substances against the pathogen. Here EGCG proved to be particularly effective at a concentration of 1 mg/ml and was able to eliminate almost all pathogens within 24 hours.

Possible future applications could be to use these substances as an addition to feed for shrimp to prevent or contaminate outbreaks from AHPND. This could significantly reduce losses in shrimp production and set new standards in disease management in aquaculture.

basic terms and concepts

• aquaculture: the breeding and keeping of aquatic animals or plants in controlled environments for commercial purposes.
• pathogen: a microorganism that causes diseases.
• virulence plasmid: A DNA fragment in bacteria that bears genes that can cause the disease.
• phytocompounds: chemical compounds that occur in plants, often with health advantages.
• in silico: computer -aided analysis or simulations of biological processes.
• docking score: a measure of the binding strength and affinity of a molecule of a target protein in biochemistry.
• molecular dynamics: A technology that simulates the physical movements of atoms and molecules.
• RMSD (Root Mean Square Deviation): A statistical measure for the differences between observed and calculated positions of molecules.
• Mic (minimal inhibition concentration): The lowest concentration of an antimicrobial agent that prevents the growth of microorganism.
• MBC (minimal bactericide concentration): The lowest concentration of a means that kills 99.9 % of the bacterial population.

abbreviations

• ahpnd: acute hepatopancreatic necrosis disease
• myr: MyricTin
• TF: (+)-Taxifolin
• EGCG: (-)-Epigallocatechin-3-gallate
• Stn: Strychnin
• RMSD: Root Mean Square Deviation
• Mic: minimal inhibition concentration
• MBC: Minimal bactericidal concentration

Effective phytocompounds against Vibrio Parahaemolyticus in the garnish breeding

In the Southeast Asian shrimp breeding, the disease "Acute Hepatopancreatic Necrosis Disease" (AHPND) is a significant threat. The main cause, the bacterium vibrio parahaemolyticus , is particularly devastating for the highly sought -after pacifier white shrimp ( litopenaeus Vannamei ). This research identifies the mechanisms and potential biochemical inhibitors against the pathogenicity of v. Parahaemolyticus .

Pathogenetic mechanism

The pathogenicity path of v. Parahaemolyticus is based on a virulence plasmid that encodes binary protein toxins (Pira/B). These toxins are responsible for the destruction of the cells and can be conjugatively transferred to other vibrio -species by means of a system for post-segregational killing.

in silico analysis and molecular dynamic studies

Four phytocompounds-Myrictin (MYR), (+)-Taxifolin (TF), (-)-Epigallocatechingallat (EGCG) and Strychnin (STN)-selected, selected, based on docking scores and affinity. The analysis with the Discovery Studio Software identified critical amino acid interior interactions that are necessary for the binding. Molecular dynamic simulations showed that in particular (+) taxifoline and (-)-Epigallocatechingallat with lower root mean Square deviation (RMSD) values ​​and improved stability against protein toxins.

antibacterial effectiveness

The antibacterial effectiveness of the selected phytocompounds was determined by determining the minimal inhibition concentration (MIC) and the minimal bactericidal concentration (MBC) against pathogenic tribes of v. parahaemolyticus tested. The best MBC results were recorded with 1 mg/ml for EGCG and 1.25 mg/ml for TF. After 24 hours of incubation, a complete reduction in the viable cell numbers in these concentrations could be observed.

FAZIT

This study provides valuable insights into the use of phytocompounds as potentially efficient inhibitors against vibrio parahaemolyticus , especially with regard to their application in aquaculture to combat AHPND. Further studies could lead to the development of new treatment strategies based on phytocompounds.

Further information on research can be found in the original study at: https://pubmed.nlm.nih.gov/3698845 .