Abstract
The abuse of antibiotics in aquaculture and livestock no doubt has exacerbated the increase in antibiotic-resistant bacteria, which imposes serious threats to animal and human health. The exploration of substitutes for antibiotics from marine animals has become a promising area of research, and antimicrobial peptides (AMPs) are worth investigating and considering as potential alternatives to antibiotics. In the study, we identified a novel AMP gene from the mud crab Scylla paramamosain and named it Sparanegtin. Sparanegtin transcripts were most abundant in the testis of male crabs and significantly expressed with the challenge of lipopolysaccharide (LPS) or Vibrio alginolyticus. The recombinant Sparanegtin (rSparanegtin) was expressed in Escherichia coli and purified. rSparanegtin exhibited activity against Gram-positive and Gram-negative bacteria and had potent binding affinity with several polysaccharides. In addition, rSparanegtin exerted damaging activity on the cell walls and surfaces of P. aeruginosa with rougher and fragmented appearance. Interestingly, although rSparanegtin did not show activity against V. alginolyticus in vitro, it played an immunoprotective role in S. paramamosain and exerted an immunomodulatory effect by modulating several immune-related genes against V. alginolyticus infection through significantly reducing the bacterial load in the gills and hepatopancreas and increasing the survival rate of crabs.
Highlights
Publisher’s Note: MDPI stays neutralIt is estimated that China accounts for over 60% of the global aquaculture production under the accelerated development of aquaculture industry [1]
In the study, based on the transcriptome database of S. paramamosain established by our laboratory, we identified an uncharacterized gene for the first time and named it Sparanegtin
This study aims to characterize the new antimicrobial peptides (AMPs) Sparanegtin, elucidating its immune-protective effect and the underlying mechanism and developing a potential effective antimicrobial agent that could be substituted for antibiotics to be used in animal husbandry or medicine in the future
Summary
Publisher’s Note: MDPI stays neutralIt is estimated that China accounts for over 60% of the global aquaculture production under the accelerated development of aquaculture industry [1]. Through the consumption of aquatic products tainted by antibiotics, humans may acquire adverse drug reactions [2]. The abuse of antibiotics increased numbers of antibiotic-resistant pathogenic microorganisms in the aquatic environment, which poses a challenge to the development and use of antibiotic strategies to control fish diseases [3,4]. As it is known that antibiotic medications have been widely used in clinical treatment and the prevention of microbial infections, and in feedstuffs [5], the wide spread of antimicrobial resistance (AMR) seriously affects animal and human health [6]. To control the antibiotic-resistant pathogens, a variety of effective first-line drug treatments
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