The Antioxidant Effect of Natural Antimicrobials in Shrimp Primary Intestinal Cells Infected with Nematopsis messor

Abstract

Nematopsis messor infections severely impact on shrimp’s health with devastating economic consequences on shrimp farming. In a shrimp primary intestinal cells (SGP) model of infection, a sub-inhibitory concentration (0.5%) of natural antimicrobials (Aq) was able to reduce the ability of N. messor to infect (p < 0.0001). To prevent N. messor infection of SGP cells, Aq inhibits host actin polymerization and restores tight junction integrity (TEER) and the expression of Zo-1 and occluding. The oxidative burst, caused by N. messor infection, is attenuated by Aq through the inhibition of NADPH-produced H2O2. Simultaneous to the reduction in H2O2 released, the activity of catalase (CAT) and superoxide dismutase (SOD) were also significantly increase (p < 0.0001). The antimicrobial mixture inactivates the ERK signal transduction pathway by tyrosine dephosphorylation and reduces the expression of DCR2, ALF-A, and ALF-C antimicrobial peptides. The observed in vitro results were also translated in vivo, whereby the use of a shrimp challenge test, we show that in N. messor infected shrimp the mortality rate was 68% compared to the Aq-treated group where the mortality rate was maintained at 14%. The significant increase in CAT and SOD activity in treated and infected shrimp suggested an in vivo antioxidant role for Aq. In conclusion, our study shows that Aq can efficiently reduce N. messor colonization of shrimp’s intestinal cells in vitro and in vivo and the oxidative induced cellular damage, repairs epithelial integrity, and enhances gut immunity.

Natural Antimicrobials Promote the Anti-Oxidative Inhibition of COX-2 Mediated Inflammatory Response in Primary Oral Cells Infected with Staphylococcus aureus, Streptococcus pyogenes and Enterococcus faecalis

“…The plates were gently centrifuged at 250× g for 5 min and incubated for a further 3 h. The cell-associated bacteria were estimated by washing the infected monolayers (3×) with PBS followed by exposure to 0.1% Triton X-100 in PBS for 15 min at 41.5 • C and 37 • C. Dilutions (10-fold) of infected or control wells were plated onto TSAYE agar and incubated for 2 days prior to enumeration, at 37 • C. All assays were performed in triplicate and on three separate days. Cytotoxicity of Auraguard was determined as previously described [34] by utilizing the MTT assay (Sigma-Aldrich, Gillingham, England, UK).…”

Natural Antimicrobials Block the Host NF-κB Pathway and Reduce Enterocytozoon hepatopenaei Infection Both In Vitro and In Vivo

“…The current antimicrobial mixture using (Aq) was earlier shown to reduce N. messor virulence by avoiding actin polymerization and improving cell-membrane integrity. The antipathogenic mechanism includes increased SOD and CAT activity, lower H 2 O 2 levels and inactivation of the ERK signal transduction pathway [ 14 ]. Our study shows that, in the case of EHP infection, we have also observed increased CAT and SOD activity; however, the regulatory mechanism involves the inactivation of the NF-κB pathway by Aq, an effect caused by the reduction in H 2 O 2 production.…”

“…The SGP cells were prepared [ 14 ] and characterised [ 18 ] as previously described. Briefly, the SGP cells were grown in 24 plastic well plates (Analab, Lisburn, UK) in the presence of 0.1% DMSO (Thermo-Fischer, Gloucester, UK) media supplemented with 20% fetal bovine serum (FBS), 100 µg penicillin, 8% shrimp head extract, 6% salt solution, 20 ng epidermal growth factor (Sigma-Aldrich, Gillingham, UK), and 10 U/mL human recombinant interleukin 2 (Sigma-Aldrich, Gillingham, UK).…”

“…In the absence of scientific data explaining how organic acids (natural antimicrobials) may influence the virulence of EHP and the downstream impact on host oxidative stress, such research is vital. Mixtures of natural antimicrobials, such as AuraAqua (Aq), were previously shown to reduce oxidative stress, prevent infection, and enhance the immune response in Nematopsis messor -infected shrimp epithelial cells [ 14 ]. Also, Aq was instrumental in improving the gut health of Vibrio parahaemolyticus -infected shrimp gut primary cells (SGP) by stimulating the growth and development of host probiotics such as Faecalibacterium prausnitzii [ 15 ].…”

The Effect Citrox BCL on Legionella pneumophila Mechanisms of Biofilm Formation, Oxidative Stress and Virulence

“…The supernatant was finally harvested and diluted appropriately with sterile distilled water and subsequently cultured on BCYE-α agar. The cytotoxicity of Citrox BCL was determined as previously described [ 20 ] using the MTT assay (Sigma-Aldrich, Gillingham, England, UK).…”