Dual-Defense Functionality of Temporin-1LS From Dark-Spotted Frogs: Antimicrobial Activity and I

10 Apr 20264 min read0 viewsJournal Feed

GIST

IntroductionThe escalating crisis of antibiotic resistance highlights the urgent need for novel antimicrobial agents. This study aims to identify and characterize temporin-1LS, a temporin-family antimicrobial peptide from the dark-spotted frog (Pelophylax nigromaculatus), and to investigate its biological functions, including antimicrobial and immunomodulatory activities.

MethodsStructural and phylogenetic analyses were conducted to determine the peptide’s conformation and evolutionary relationship. Expression levels of temporin-1LS in various tissues were assessed under basal and pathogen-challenged conditions using Aeromonas hydrophila.

The antimicrobial activity of synthetic temporin-1LS was evaluated by determining minimum inhibitory concentrations (MICs) against bacterial strains. Immunomodulatory functions, including macrophage chemotaxis, phagocytosis, and respiratory burst, were examined in vitro.

ResultTemporin-1LS possesses a conserved amphipathic α-helical structure and shows high phylogenetic homology with temporin-1GY. It was constitutively highly expressed in frog skin and significantly upregulated in the gut (47.4-fold) and liver (24.3-fold) following A.

hydrophila challenge. The synthetic peptide exhibited potent and selective antibacterial activity against Staphylococcus warneri and Vibrio alginolyticus (MIC = 3.125 µg/mL).

Clinical Editorial

Study aim and design

The work identifies and characterizes temporin-1LS, a temporin-family antimicrobial peptide from Pelophylax nigromaculatus, and examines both its antimicrobial activity and immunomodulatory effects.
Methods encompassed structural and phylogenetic analyses to define conformation and evolutionary relationships, tissue expression under basal and pathogen-challenged conditions with Aeromonas hydrophila, MIC determination against bacterial strains for the synthetic peptide, and in vitro assessments of macrophage chemotaxis, phagocytosis, and respiratory burst.

Biophysical and evolutionary context

Temporin-1LS features a conserved amphipathic α-helical structure.
Phylogenetically, it shows notable homology with temporin-1GY.

Expression dynamics and challenge response

hydrophila exposure, expression rises markedly in the gut (approximately 47.4-fold) and liver (approximately 24.3-fold).

In frog skin the peptide is constitutively expressed at high levels.
Following A.

Antimicrobial activity and context

hydrophila, yet administration of temporin-1LS improved survival in a frog infection model, indicating in vivo efficacy beyond direct in vitro activity.

Synthetic temporin-1LS demonstrated potent, selective activity against Staphylococcus warneri and Vibrio alginolyticus, with an MIC of 3.125 µg/mL.
At higher concentrations (50–100 μg/mL), the peptide increased bacterial LDH release relative to a BSA control, suggesting potential membrane-disruptive effects under those conditions.
Notably, it did not show measurable in vitro antibacterial activity against A.

Immunomodulatory effects on macrophages

Temporin-1LS robustly modulates innate immune functions in macrophages.
It enhances chemotaxis by about 2.4-fold, increases phagocytic activity by around 4.4-fold, and augments respiratory burst by approximately 1.6-fold, in a dose-dependent manner.

Context, interpretation, and limitations

hydrophila and reliance on a frog infection model to demonstrate survival benefit; broader in vivo validation and mechanistic dissection of immunomodulation remain open questions.

The findings support a dual-defense mechanism: direct antibacterial effects against specific pathogens and augmentation of macrophage-mediated antimicrobial functions.
Limitations explicitly reported include the lack of in vitro activity against A.