Toposome: Source of antimicrobial molecules in the gonads of the sea urchin Lytechinus variegatus (Lamarck, 1816)

• Published in: Fish & shellfish immunology Vol. 109; pp. 51 - 61
• Main Authors: Figueiredo, DAL, Santos, WS, Montoni, Fabio, Iwai, Leo Kei, Silva Junior, PI
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-02-2021
• Subjects: Amino Acid Sequence; Animals; Anti-Infective Agents - immunology; Antimicrobial protein; Ecological behavior; Female; Gender differences; Gene Expression Profiling; Glycoproteins - chemistry; Glycoproteins - genetics; Glycoproteins - immunology; Immunity, Innate - genetics; Innate immune system; Lytechinus - genetics; Lytechinus - immunology; Male; Marine natural compounds; Ovary - immunology; Ovary - metabolism; Reproduction; Sequence Alignment; Testis - immunology; Testis - metabolism; Reproduction; Innate immune system; Gender differences; Antimicrobial protein; Ecological behavior; Marine natural compounds
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2020.11.023

Sea urchins live in a challenging environment that requires rapid and efficient responses against pathogens and invaders. This response may be also important in reproductive processes once males and females release their gametes into water. In addition, the gonads are organs with dual function: reproductive organ and nutrient reserve, therefore it needs efficient protective mechanisms to preserve the nutrients as well as the reproductive cells. The aim of this study was to evaluate the presence and characterize antimicrobial molecules in the male and female gonads of the sea urchin Lytechinus variegatus. Through HPLC purification, antimicrobial activity test and mass spectrometry several antimicrobial molecules were found in the gonads of both gender. Computational in silico analyses showed that they are fragments of a glycoprotein called toposome, also known as major yolk protein (MYP) which is one of the major proteins found in the gonads. Although different functions have been reported for this protein, this is the first description of a direct antimicrobial activity in Lytechinus variegatus. The results indicate that when undergoing proteolysis the toposome generates different fragments with antimicrobial activity which may indicate the importance of a rapid defense response strategy against invading microorganisms in the gonads used by both males and females sea urchins.
•The presence of antimicrobial molecules were investigated in the gonads of L. varegatus.•Several antimicrobial molecules have been found in both females and males.•Male and female seems to present the same antimicrobial molecules.•The results indicate that toposome fragments have antimicrobial activity in the gonads.•Protein fragments show similarity with other antimicrobial peptides already described.