Molecular docking study of bio-inhibitors extracted from marine macro-alga Ulva fasciata against hemolysin protein of luminescence disease-causing Vibrio harveyi.

Krishnamoorthy Sivakumar,Akshaya Panigrahi,Balakrishnan Vijayakumar,Sudalayandi Kannappan,Karingalakkandy Poochirian Jithendran,Sivamani Balasubramaniam

doi:10.1007/s00203-021-02408-1

Abstract

Shrimp grow-out and hatchery systems are being affected by bacterial disease particularly Vibrios. The use of chemotherapeutic agents in aquaculture practices has to lead to the development of resistance among aquatic bacteria. Thus, health management becomes of major importance in aquaculture. Under this situation, progressing bio-inhibitors from marine resources are most appropriate to be considered against pathogenic bacteria. Molecular docking is an appropriate tool in structural biology and computer-assisted drug design to predict and neutralize a target protein of known diseases. In this study, marine macro-alga Ulva fasciata was aimed at developing inhibitors against luminescence disease-causing pathogenic bacteria Vibrio harveyi. U. fasciata was collected from Thoothukudi, Tamil Nadu, India. Extract of U. fasciata was tested against growth and virulence factors of V. harveyi during Penaeus monodon larviculture. Further U. fasciata extract was subjected to GC-MS analysis to identify the biomolecules. The homology modeling of virulent protein, hemolysin of V. harveyi was designed in this study. Hence, it was aimed for molecular docking against the biomolecules identified from U. fasciata extract. During shrimp larviculture, the extract of U. fasciata (200μgmL-1) exhibited reduction on Cumulative Percentage of Mortality (32.40%) in postlarvaeagainst challenge of V. harveyi infection. Biomolecule Methyl dehydroabietate had showed highest binding affinity among the compounds was evaluated in molecular docking study. Statistical analysis had revealed significant differences (p < 0.05) in trials. Therefore, it was proved that the bio-inhibitors from U. fasciata will be a better option for controlling luminescence disease-causing V. harveyi in shrimp grow-out practices.

Highlights

The grow-out practices under the aquaculture sector are major sources in generating job opportunities and revenue to business sectors
The homology modeling of virulence of hemolysin protein of V. harveyi was designed and used for docking studies against the compounds of U. fasciata as identified by Gas Chromatography and Mass Spectrometry (GC-MS) analysis
The strains were pre-enriched in alkaline peptone water (APW) and serially diluted with normal saline (0.85 % NaCl w/v), 0.1 ml of each sample was surface spread on Thiosulphate citrate bile salt sucrose agar medium (TCBS), Seawater complex agar (SWC) and V. harveyi selective agar medium (VHSA)

Summary

Introduction

The grow-out practices under the aquaculture sector are major sources in generating job opportunities and revenue to business sectors. The shrimp grow-out practices have developed rapidly across the world due to the increased market demand (Harlioglu and Farhadi 2017). While considering bacterial diseases in shrimp culture Vibrio bacteria producing disease is known as Vibriosis a major contributor to other disease-causing agents (Krupesha‐Sharma et al 2016). Among other Vibrio bacteria, V. harveyi a bioluminescent bacterium, is a potent pathogen and resulting in major mortalities in grow-out and hatchery units. During its pathogenesis in host organisms, V. harveyi produces many extra-cellular virulence factors such as bioluminescence, proteases, phospholipases, lipases, siderophores, chitinases, hemolysins, etc (Soto-Rodriguez et al 2012). V. harveyi is associated with other luminescent Vibrios (Raissy et al 2011) to spread diseases during the grow-out practices of shrimp Penaeus monodon and Litopenaeus vannamei. The mass mortalities resulting infections by V. harveyi were reported up to 80-100% in shrimp grow-out and larviculture system (Raissy et al 2011)

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