A Novel Antimicrobial Peptide Sparamosin26–54 From the Mud Crab Scylla paramamosain Showing Potent Antifungal Activity Against Cryptococcus neoformans

Abstract

Due to the increasing prevalence of drug-resistant fungi and the limitations of current treatment strategies to fungal infections, exploration and development of new antifungal drugs or substituents are necessary. In the study, a novel antimicrobial peptide, named Sparamosin, was identified in the mud crab Scylla paramamosain, which contains a signal peptide of 22 amino acids and a mature peptide of 54 amino acids. The antimicrobial activity of its synthetic mature peptide and two truncated peptides (Sparamosin1–25 and Sparamosin26–54) were determined. The results showed that Sparamosin26–54 had the strongest activity against a variety of Gram-negative bacteria, Gram-positive bacteria and fungi, in particular had rapid fungicidal kinetics (killed 99% Cryptococcus neoformans within 10 min) and had potent anti-biofilm activity against C. neoformans, but had no cytotoxic effect on mammalian cells. The RNA-seq results showed that after Sparamosin26–54 treatment, the expression of genes involved in cell wall component biosynthesis, cell wall integrity signaling pathway, anti-oxidative stress, apoptosis and DNA repair were significantly up-regulated, indicating that Sparamosin26–54 might disrupt the cell wall of C. neoformans, causing oxidative stress, DNA damage and cell apoptosis. The underlying mechanism was further confirmed. Sparamosin26–54 could bind to several phospholipids in the cell membrane and effectively killed C. neoformans through disrupting the integrity of the cell wall and cell membrane observed by electron microscope and staining assay. In addition, it was found that the accumulation of reactive oxygen species (ROS) increased, the mitochondrial membrane potential (MMP) was disrupted, and DNA fragmentation was induced after Sparamosin26–54 treatment, which are all hallmarks of apoptosis. Taken together, Sparamosin26–54 has a good application prospect as an effective antimicrobial agent, especially for C. neoformans infections.

Truncated Pleurocidin Derivative with High Pepsin Hydrolysis Resistance to Combat Multidrug-Resistant Pathogens

“…In addition, GK-4 can also cause the loss of bacterial membrane potential and the production of ROS. This is also consistent with a series of previous research results [ 49 , 50 , 51 ], that is, the loss of membrane potential and the production of ROS are the key factors for the bactericidal activity of many antibiotics.…”

Comparative study on antibacterial characteristics of the multiple liver expressed antimicrobial peptides (LEAPs) in teleost fish

“…In addition to their broad-spectrum antibacterial activities, AMPs can also inhibit fungi, viruses and parasites ( 6 ). Compared with other species, some AMPs derived from fish, shrimp, crabs and other aquatic animals have unique structures and functions ( 7 , 8 ).…”

A Novel Antimicrobial Peptide Spampcin56–86 from Scylla paramamosain Exerting Rapid Bactericidal and Anti-Biofilm Activity In Vitro and Anti-Infection In Vivo

“…Further studies are needed to obtain its recombinant protein and confirm its immune-related functions in vitro and in vivo. Other novel AMPs, such as Sparamosin 26–54 [ 17 ], Sphistin [ 7 , 18 ], SpHyastatin [ 19 ], Sp-NPFin [ 20 ], etc., including the above AMPs as mentioned, all play an important role in the innate immunity of S. paramamosin and have good prospects for future applications in aquaculture and medicine. Here, in this study, another novel functional gene with high AMP potential, named Spampcin, was characterized from S. paramamosain and its derived truncated peptide Spa31 had been confirmed to exhibit broad-spectrum and potent antibacterial and antifungal activity, and several shortened Spa31-derived peptides (Spa20, Spa22, and Spa14) also had certain antimicrobial activity.…”

“…The effects of Spa31 on S. aureus and P. aeruginosa were observed using SEM. The steps to prepare SEM samples refer to a previous study [ 17 ]. Briefly, 6 μM of Spa31 was incubated with the bacteria (1 × 10 7 CFU mL −1 ) first.…”